Multiple power supply apparatus with improved installability

In a multiple power supply apparatus installed in a vehicle, a first power supply system includes a generator and a first battery. The generator is driven by an operation of the engine. The first battery is chargeable by an electrical output of the generator. A second power supply system includes a second battery. The second battery works to supply electrical power to an electrical load installed in the vehicle. A power transfer module is operative to transfer electrical power supplied from the first power supply system based on at least one of the electrical output of the generator and a charged level of the first battery to the second power supply system. The power transfer module is integrally joined to the first battery to constitute a battery module.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is based on Japanese Patent Applications 2006-077598, 2006-077606, 2006-077613, and 2006-077618 filed on Mar. 20, 2006, respectively. This application claims the benefit of priority from these applications, so that the descriptions of which are all incorporated herein by reference.

FIELD OF THE INVENTION

The present invention relates to multiple power supply apparatuses having improved installability. The present invention also relates to air-cooled power systems with a simplified structure.

BACKGROUND OF THE INVENTION

Recently, power supply apparatuses with two different voltage batteries have been installed in hybrid vehicles and engine vehicles. The power supply systems with two different voltage batteries will be referred to as “dual voltage apparatuses” hereinafter.

A dual voltage apparatus is normally equipped with a first power supply system including an engine-driven generator and a higher battery. The higher battery is chargeable by the engine-driven generator and has a first nominal voltage level. The dual voltage apparatus is normally equipped with a second power supply system including a lower battery with a second nominal voltage level lower than the first nominal voltage level. The second power supply system works to supply power to in-vehicle electrical loads.

The dual voltage apparatus is normally equipped with a power transfer unit electrically coupled to the first and second power supply systems. The power transfer unit is operative to convert a level of an output voltage of the first power supply system into a target level required for the second power supply system, and to transfer the output voltage, whose level has been converted, to the second power supply system.

Specifically, in the dual voltage apparatus, transfer of the output voltage from the first power supply system to the second power supply system via the power transfer unit allows level variation in a power supply voltage for the electrical loads to be reduced.

In the dual voltage apparatus, because power can be securely supplied to the electrical loads from the second power supply system, it is possible to change the state of charge (SOC) of the first higher battery when:

the higher battery voltage is output for driving torque generation; the higher battery is charged by regenerative electric power generated by the generator when braking; or the higher battery voltage is output for torque assist of the engine.

Especially, when the engine is not moving, power supply can be carried out from the higher battery to the electrical loads, making it possible to reduce level variation in an output voltage of the second power supply system.

Note that the electrical loads for example include lighting equipment, sound devices, and control units, which are susceptible to decrease in power supply voltage.

An example of the dual voltage apparatuses is disclosed in U.S. Patent Publication No. 6,583,602 corresponding to Japanese Unexamined Patent Publication No. 2002-345161, which was assigned to the same assignee.

In a dual voltage apparatus described above, power transfer can be carried out from the lower battery to the higher battery in order to make up for a shortage of the higher battery in capacity. As the higher battery, lithium secondary batteries, secondary batteries using a hydrogen storing alloy, and electric double layer capacitors can be used. As the lower battery, lead secondary batteries with high cost efficiency can be preferably used. Especially, the lithium secondary batteries have high charging capacity per weight, which can enhance fuel economy based on reduction in vehicle weight.

On the other hand, cooling systems for in-vehicle power devices through which a large amount of current is passed normally use a liquid or air cooling medium to be contacted onto a heatsink. For example, Japanese Unexamined Patent Publications No. H04-275492, H06-303704, and 2004-82940 disclose in-vehicle power devices equipped with corresponding air-cooling systems, respectively. Japanese Unexamined Patent Publication No. H09-126617 discloses an in-vehicle power device equipped with both air-cooling and liquid-cooling systems.

In addition, Japanese Unexamined Patent Publication No. 2004-39641 discloses a charging system with an air-cooling system in which airflow generated by a fan allows a battery and a charging device to be cooled.

Such liquid-cooling systems essentially include issues in which the more the system scale increases with the system structure complicated, the more the weight and a space required for installation of liquid-cooling systems increase. This makes it difficult to install such a liquid-cooling system in in-vehicle power devices.

Especially, in a liquid-cooling system, the heat transfer area between a heating element and a heat transfer medium can be reduced. However, it is difficult to reduce a heat transfer area of an indirect heat exchange unit required to dissipate heat absorbed by the heat transfer medium into the atmosphere.

For these reasons set forth above, in view of reduction in size and weight, an air-cooling system that subjects a heating element, a heat transfer medium stably contacted onto the heating element, or a heat pipe to cooling air can be preferably used. This air-cooling system has an advantage over a liquid-cooling system in reduction in size and weight, which makes it possible to increase the reliability of the air-cooling system.

Returning to the dual voltage apparatuses, as compared with power supply apparatuses with a single battery, the dual voltage apparatuses require, in addition to a first battery for supplying power to electrical loads, at least a second battery chargeable by a generator, and a power transfer unit for transferring power between the first and second batteries.

When install of the first and second batteries and the power transfer unit in a comparatively small-sized engine compartment located in front of a vehicle, they may be randomly arranged in the engine compartment, and thereafter, the first and second batteries and the power transfer unit may be electrically connected to each other by cables.

In this case, however, the cables may be routed for comparatively long distances in the engine compartment, causing the routing of the cables to be complicated.

The long and complicated routings of the cables may make it difficult to locate some of the cables away from high-temperature devices and/or rotating members located in the engine compartment. The former may result in malfunction in some of the cables, and the latter may interfere with the rotation of the rotating members.

The long and complicated routings of the cables may make it difficult to prevent some of the cables from being located close to the front (forward end) of the vehicle. This may cause brakes in some of the cables to be unavoidable in the event of a frontal crash.

In order to address the problems, the first battery and the power transfer unit may be installed in a trunk located at the rear of the vehicle. This way however may cause substantially identical problems due to the long and complicated routings of the cables by which the first and second batteries and the power transfer unit are connected to each other.

The long and complicated routings of the cables may increase:power loss due to increase in resistance of the cables; andweight of the dual voltage apparatus.

In addition, there are various types of vehicles, such as engine vehicles driven by drive torque imparted by internal combustion engines, hybrid vehicles driven by drive torque and motor torque, and electric vehicle driven by motor torque. These various types of vehicles normally use a plurality of control units including inverters for motor control and/or DC to DC converters.

The control units installed in the various vehicles are operative to switch on and off power semiconductor devices that operate at high values of power, which may cause the power semiconductor devices, such as power transistors, to generate heat. For this reason, it is important to cool the power semiconductor devices installed in the control units.

Similarly, because in-vehicle batteries containing electric double layer capacitors repeatedly are frequently charged and discharged depending on variations in power required for in-vehicle electrical loads, they may internally generate a large amount of heat. Thus, it is also important to cool the in-vehicle batteries.

On the other hand, in the Unexamined Patent Publication No. 2004-39641, the air-cooling system, which is composed of a cooling fan, a motor that drives the cooling fan, and a motor controller that controls the motor, needs to be installed in the charging system integrated with the battery. This may cause the charging system to increase in size and weight, and cause the charging system structure to be complicated. In addition, the charging system structure may increase power consumption of the whole of the components (the cooling fan, motor, and motor controller), which may cause the battery to be exhausted.

This may not be avoided even if the cooling fan is separately arranged from the charging system, which is disclosed in the Publication No. 2004-39641.

As described above, installation of the air-cooling system in the charging system may cause the cost and/or the fuel consumption of the vehicle to deteriorate.

SUMMARY OF THE INVENTION

In view of the background, an object of at least one aspect of the present invention is to provide multiple voltage supply apparatuses installed in a vehicle, each of which has improved installability.

In view of the background, another object of at least one aspect of the present invention is to provide air-cooled power systems each installed in a vehicle, each of which is capable of effectively cooling a power device with a simplified structure; this power device generates heat when energized.

According to one aspect of the present invention, there is provided a multiple power supply apparatus installed in a vehicle including an engine. The multiple power supply apparatus includes a first power supply system. The first power supply system includes a generator and a first battery. The generator is driven by an operation of the engine. The first battery is chargeable by an electrical output of the generator. The multiple power supply apparatus also includes a second power supply system. The second power supply system includes a second battery. The second battery works to supply electrical power to an electrical load installed in the vehicle. The multiple power supply apparatus further includes a power transfer module operative to transfer, to the second power supply system, electrical power supplied from the first power supply system based on at least one of the electrical output of the generator and a charged level of the first battery. The power transfer module is integrally joined to the first battery to constitute a battery module.

According to another aspect of the present invention, there is provided a multiple power supply apparatus installed in a vehicle including an engine. The multiple power supply apparatus includes a first power supply system including a generator and a first battery. The generator is operatively connected to the engine and driven by an operation of the engine. The first battery is electrically connected to the generator and chargeable by an electrical output of the generator. The multiple power supply apparatus includes a second power supply system including a second battery. The second battery works to supply electrical power to an electrical load installed in the vehicle. The multiple power supply apparatus includes a power transfer module operative to transfer electrical power supplied from the first power supply system to the second power supply system. The electrical power supplied from the first power supply system is determined depending on at least one of the electrical output of the generator and a charged level of the first battery. The first battery and the power transfer module are arranged closer to the generator than the second battery is.

According to a further aspect of the present invention, there is provided a multiple power supply apparatus installed in a vehicle including an engine. The multiple power supply apparatus includes a first power supply system. The first supply system includes a generator and a first battery. The generator is driven by an operation of the engine. The first battery is chargeable by an electrical output of the generator. The multiple power supply apparatus includes a second power supply system including a second battery. The second battery works to supply electrical power to an electrical load installed in the vehicle. The multiple power supply apparatus includes a power transfer module operative to transfer, to the second power supply system, electrical power supplied from the first power supply system based on at least one of the electrical output of the generator and a charged level of the first battery. The multiple power supply apparatus includes a shared duct disposed in an engine compartment of the vehicle and operative to allow air to be guided toward both the first battery and the power transfer module. The air is caused by the vehicle running.

According to a still further aspect of the present invention, there is provided an air-cooled power system installed in a vehicle having a cooling fan communicated with a first airflow passage located upstream of the cooling fan and with a second airflow passage located downstream thereof. The cooling fan is operative to suck airflow through the first airflow passage and to blow out the sucked airflow to the second airflow passage so as to cool a heating element installed in the vehicle. The air-cooled power system includes a power device. The power device includes a cooling-air inlet port, a cooling-air passage, and a cooling-air outlet discharge port. The cooling-air passage is communicated with the cooling-air inlet port and the cooling-air outlet port. The power device generates heat when energized. The air-cooled power system includes a suction duct having an upstream inlet and a downstream outlet. The downstream outlet of the suction duct is located at one of the first and second airflow passages so that the airflow flowing via one of the first and second airflow passages forming a negative pressure. The negative pressure acts on the downstream outlet of the suction duct. The upstream inlet of the suction duct is located to be communicated with the cooling-air outlet port. The downstream outlet of the suction duct is arranged such that a longitudinal direction of the suction duct is undirected toward an upstream of the airflow through one of the first airflow passage and the second airflow passage.

DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION

First Embodiment

An example of the circuit structure of a multiple power supply apparatus PA installed in a vehicle according to a first embodiment of the invention is schematically illustrated inFIG. 1.

Referring toFIG. 1, the multiple power supply apparatus PA includes a generator1incorporating a rectifier. The multiple power supply apparatus PA includes a first battery2with positive and negative terminals, the positive terminal of which is electrically coupled to the generator1via a first power supply line3, and the negative terminal of which is electrically connected to a ground line.

The multiple power supply apparatus PA includes a second battery4with positive and negative terminals, the positive terminal of which is electrically coupled to a plurality of electrical loads5via a second power supply line6, and the negative terminal of which is electrically connected to the ground line.

The multiple power supply apparatus PA includes a power transfer unit7electrically coupled between the first and second power supply lines3and6, and a controller8electrically coupled to the first battery2, the second power supply line6, and the power transfer unit7.

The generator1is designed as a normal alternator. Specifically, a rotor of the generator1is coupled to a crankshaft of the engine through, for example, a belt to be rotatable therewith. When a field current is applied to field windings of the rotor that is rotating, the rotating field windings create magnetic fluxes. The created magnetic fluxes by the field windings induce a three-phase alternating current (AC) voltage in stator windings of a stator surrounding the rotor.

The three-phase AC voltage induced in the stator windings is rectified by the rectifier to a direct current (DC) voltage.

The first battery2is configured to be chargeable by the output (output DC voltage) of the generator1via the first power supply line3.

For example, as the first battery2, a lithium secondary battery with a rated voltage of 14.8 V can be preferably used. The first battery2consists essentially of a number of, for example, four series-connected cells. As the first battery2, one of other types of secondary batteries, such as secondary batteries using a hydrogen storing alloy, and electric double layer capacitors can be used. The lithium secondary batteries have high charging capacity per weight, which can enhance fuel economy based on reduction in vehicle weight.

In the first embodiment, note that the multiple power supply apparatus PA requires various protection circuits for protecting the lithium secondary cells against temperature variations, overcharging, and/or overdischarging. Thus, the multiple power supply apparatus PA can use at least some of the various types of protection circuits for protect of the lithium secondary cells against temperature variations, overcharging, and/or overdischarging. It is also to be noted that, because the structures and functions of the various types of protection circuits have been known in skilled persons in the art, the descriptions of which are omitted.

In the first embodiment, the generator1, the first battery2, and the first power supply line3constitute a first power supply system S1.

The second battery4is operative to supply power to the electrical loads5via the second power supply line6.

For example, as the second battery4, a lead secondary battery with a rated voltage of 12.7 V, which has been widely sold for automotive batteries can be preferably used. Lead secondary batteries normally have higher cost efficiency than other types of secondary batteries.

In the first embodiment, the second battery4, the electrical loads5, and the second power supply line6constitute a second power supply system S2.

The power transfer unit7is operative to transfer a DC voltage at the first power supply line3to the second power supply line6while converting a level of the DC voltage into a target level required for the second power supply system S2.

For example, the power transfer unit7is composed of a DC to DC converter with one of various types of converting circuits, such as a DC chopper. As another example, the power transfer unit7is composed of a series regulator for stepping down an input voltage by a given level equivalent to a potential difference between the first and second power supply lines3and6. As a further example, the power transfer unit7can be equipped with a switching element, such as a MOS transistor, disposed between the positive terminal of the first battery2and the first power supply line3, and/or between the negative terminal of the first battery2and the ground line. Open of the switching element allows the first battery2to be separated from the first power supply system S1as need arises.

The controller8is integrated with a microcomputer and an analog to digital converter (A/D converter) and operative to control the power transfer unit7and the like. The power transfer unit7and the controller8serve as a system-to-system power-transfer circuit module10. Specifically, at least one IC chip implementing the power transfer unit7and at least one IC chip implementing the microcomputer8are packaged with each other to provide the power-transfer circuit module10.

Specifically, the controller8is operative to carry out negative feedback control by:

reading a current voltage level Vpb at the second power supply line6depending on the output voltage level of the second battery4;

computing a deviation ΔV between the current voltage level Vpb and a target voltage level Vth that has been determined depending on, for example, operating conditions of the engine EN; and

sending control signals to the power transfer unit7based on the computed deviation.

These control signals allow the power transfer unit7to regulate the level of the DC voltage to be transferred from the first power supply line3to the second power supply line6such that the deviation ΔV becomes zero, in other words, the current voltage level Vpb at the second power supply line6is matched with the target voltage Vth.

Thus, the current voltage level Vpb at the second power supply line6depending on the output voltage level of the second battery4can be securely maintained at the target voltage level Vth during normal operating conditions of the engine EN. This makes it possible to stably supply the voltage at the second power supply line6to the electrical loads5.

When power supply of the first power supply system S1to the second power supply system S2via the power transfer unit7is interrupted, the output voltage of the second battery4can be supplied to the electrical loads5via the second power supply line6.

Note that the electrical loads5can be connected to the first power supply line3of the first power supply system S1, and the power transfer unit7can perform reverse power transfer from the second battery4to the first power supply system S1.

During vehicle deceleration or braking, regenerative power is generated by the generator1so that the output voltage of the generator1is increased. When the output voltage is greater than the voltage of the first battery2, the increased output voltage of the generator1allows a current to flow into the first battery2. The flow of the current into the first battery2allows the first battery2to be charged up to an upper limit; this upper limit is determined by a current SOC level of the battery2.

Specifically, while the output voltage of the generator1is increased to be greater than the voltage of the first battery2, the increased output voltage can be consumed in the charge of the first battery2.

After return of the vehicle running condition from the deceleration or braking, the controller8controls the power transfer unit7to discharge the regenerative power charged in the first battery2therethrough to the second power supply system6. This allows the SOC level of the first battery2to be returned to a predetermined SOC level. The predetermined SOC level is preferably determined within the range from 50% to 60%.

The voltage charged in the first battery2can be used, under the controller8, for power supply to the electrical loads5during engine starting, during torque assist of the engine G, or during idling stop operation that can automatically stop the engine G when the vehicle is not running.

As described above, the multiple power supply apparatus PA requires frequent charging and discharging of the first battery2. For this reason, as the first battery2, a lithium secondary battery is preferably adopted, which has little deterioration against repeated cycles of charging and discharging. In contrast, as the second battery4, a lead battery is preferably adopted because it has a minimum function of reducing variations in the voltage to be supplied to the electrical loads5.

FIG. 2schematically illustrates an example of the structure of the multiple power supply apparatus PA installed on, for example, a bottom11of the vehicle body constituting the bottom of an engine compartment150of the vehicle.

As illustrated inFIG. 2, the first battery2, the power-transfer circuit module10, and the second battery4are integrally mounted on the bottom11of the vehicle body with the use of at least one of various known manners to provide an integrated battery assembly100.

Specifically, the first battery2has, for example, a substantially box shaped frame, and is mounted on, for example, the rear side of the bottom11of the engine compartment150. The power-transfer circuit module10has, for example, a substantially box shaped appearance, and is fixedly mounted on the top of the first battery2, which provides a substantially box shaped battery module101.

In the installation state of the first battery2and the circuit module10on the bottom11of the vehicle body, the size of the first battery frame in its lateral cross section orthogonal to the top and bottom direction is substantially identical to the size of the appearance of the circuit module10in its lateral cross section.

The integrated battery assembly100is equipped with a battery cover15made of, for example, a suitable resin. The battery cover15has, for example, a substantially box shape with one opening, and is so mounted at the edge of its opening on the bottom11of the vehicle body as to cover the battery module101(the first battery2and the power-transfer circuit module10).

The second battery4has, for example, a substantially box shaped frame, and is mounted at one outer wall surface (outer bottom wall surface) of the frame on the battery cover15over the top of the power-transfer circuit module10, which provides the integrated battery assembly100.

In the installation state of the second battery4on the battery cover15over the top of the battery module101, the size of the second battery frame in its lateral cross section is larger than the size of the appearance of the battery module101in its lateral cross section.

A battery holding plate12has an area larger than that of an outer top wall surface of the second battery4, and is coaxially mounted on the outer top wall surface of the second battery4such that an edge portion of the battery hold plate12projects from the second battery4.

At least a pair of long bolts13is fit to penetrate through a corresponding pair of through holes formed at the edge portion of the battery holding plate12. For example, one of the through holes is located opposing the other in the front and rear (longitudinal) direction of the vehicle. One end of each long bolt13is fixed to the bottom11of the vehicle body, and, into the other projecting end thereof, a nut14is screwed. Thus, screw of the nut14toward the bottom11of the vehicle body allows the battery holding plate12to clamp the integrated battery assembly100on the bottom11of the vehicle body.

The electrically isolated battery cover15allows the battery module101to be protected electrically and mechanically. The battery cover15can prevent the weight of the second battery4from being directly applied onto the battery module101.

The second battery4has a pair of positive and negative terminals41and42; the positive terminal41is electrically connected to the second power supply line6and to one end of a first bus bar16. Similarly, the negative terminal42is electrically connected to a ground, and to one end of a second bus bar17. The first and second bus bars16and17extend in a horizontal direction orthogonal to the top and bottom direction, and thereafter, further extend toward the power-transfer circuit module10so as to be electrically connected to high-side and low-side output terminals of the power-transfer circuit module10.

FIG. 3schematically illustrates an example of the structure of the power-transfer circuit module10, which is viewed from the front side of the vehicle toward the rear side.

As illustrated inFIG. 3, the power-transfer circuit module10includes a metal base plate71, double-sided electrode first and second card modules72and73each integrated with a power MOS transistor, a controller8designed as a semiconductor module (an IC chip), heatsinks74and75, a resin mold package76, and an insulating sheet77. The controller8has a plurality of pins, and the first and second card modules72and73have lead electrodes78corresponding to control electrodes, such as gate electrodes of the MOS transistors, respectively. The lead electrodes78of the first and second card modules72and73are electrically connected to corresponding pins of the controller8, respectively.

The power-transfer circuit module10includes a metal gas duct79for guiding high-pressure gas generated by electrode active materials and/or an electrolyte inside the first battery2.

The gas duct79has, for example, a substantially half-cylindrical shape, and is fixed at its outer peripheral surface to the center of an outer surface (bottom surface inFIG. 3) of the resin mold76such that a gas guiding passage formed inside the gas duct79is parallel to the front and rear direction (longitudinal direction) of the vehicle.

For example, the controller chip8is fixedly mounted on the center of one surface of the base plate71via the insulating sheet77. Similarly, the first and second card modules72and73are fixedly mounted at their one surfaces721and731on the one surface of the base plate71at both sides of the controller chip8via the insulating sheet77.

The heatsinks74and75have a substantially rectangular parallelepiped shape. The heatsinks74and75are fixedly mounted at its one surfaces on the other surfaces720and730of the first and second card modules72and73opposite to the one surfaces721and731, respectively. The controller chip8, the card modules72and73, and the heatsinks74and75are encapsulated by the resin mold package76on the base plate71with the other surfaces of the heatsinks74and75opposing the one surfaces exposed. The resin mold package76allows the IC components72,73and8to be insulated from each other except for electrical wiring thereamong.

Both surfaces720and721of the first card module72constitute main electrodes, such as drain and source electrodes, of the MOS transistor integrated therein, respectively.

In the first embodiment, the other surface720of the first card module72is contacted onto the heatsink74, and the heatsink74is electrically connected to the first power supply line3. This allows one of the main electrodes of the MOS transistor of the first card module72to be electrically connected to the first power supply line3. Similarly, the other surface730of the second card module73is contacted onto the heatsink75, and the heatsink75is electrically connected to the ground line. Specifically, for example, the heatsink75of the power-transfer circuit module10serves as a low-side output terminal thereof so that the other of the main electrodes of the MOS transistor of the second card module73to be grounded. For example, the second bus bar17of the second battery4is electrically connected to the heatsink75to be grounded.

The one surface721of the first card module72serves as the other of the main electrodes of the MOS transistor thereof, and the one surface731of the second card module73serves as the other of the main electrodes of the MOS transistor thereof. The first and second card modules72and73are electrically connected to each other by, for example, wires to serve as a DC to DC converter. The base plate71is electrically connected to the controller8and the first and second card modules72and73through the insulating layer77to serve as a high-side output terminal that is electrically connected to the second power supply line6and to the first bus bar16of the second battery4.

The other surface of the base plate71is formed with a plurality of metal plate-like fins710projecting therefrom upward at regular intervals in the side to side direction (width direction) of the vehicle orthogonal to the longitudinal direction thereof. The fins710extend in parallel to the longitudinal direction of the vehicle. Spaces formed between the individually adjacent fins710provide cooling-air passages in the longitudinal direction of the vehicle.

Similarly, the other surfaces of the heatsinks74and75are formed with a plurality of metal plate-like cooling fins741and751, respectively. For example, the heatsinks74and75(cooling fins741and751) are made of a metallic material having high heat capacity and a good thermal conductivity so as to be formed to have a wide radiating surface.

The cooling fins741and751project from the respective other surfaces of the heatsinks74and75downward at regular intervals in the side to side direction of the vehicle. The cooling fins741and751extend in parallel to the front and rear direction of the vehicle. Spaces formed between the individually adjacent cooling fins741and751provide cooling-air passages in the front and rear direction of the vehicle.

The power-transfer circuit module10includes a metal gas duct79for guiding high-pressure gas generated by electrode active materials and/or an electrolyte inside the first battery2. The gas duct79is fixed to the center of an outer surface (bottom surface inFIG. 3) of the resin mold76such that the gas guiding direction is parallel to the longitudinal direction of the vehicle.

Note that the structure of the power-transfer circuit module10schematically shows an example of circuit modules adopting one of various types of DC to DC converter circuits serving as the power transfer unit7. Specifically, the base plate71, and the heatsinks74and75can be individually provided in a power-transfer circuit module independently of electrodes of a DC to DC converter of the power-transfer circuit module. As the power transfer unit7, one of various types of series regulators can be adopted.

FIG. 4schematically illustrates an example of the structure of the battery module101constructed by the power-transfer circuit module10and the first battery2, which is viewed from the front side of the vehicle toward the rear side.FIG. 5schematically illustrates the structure of the battery module101illustrated inFIG. 4, which is viewed from one side (left side) of the vehicle toward the other side (right side).

Note that the left side and right side are determined with reference to the forward travel direction of the vehicle.

As illustrated inFIGS. 4 and 5, the box-shaped frame of the first battery2has an outer bottom wall surface mounted on the bottom11, and an outer top wall surface opposing the outer bottom wall surface. The first battery2is provided at its top wall of the frame with a gas vent (through hole) V communicated with the inside of the first battery2and located opposing the gas guiding passage of the gas duct79. The first battery2is also provided with a safety valve20so mounted on the outer top wall surface as to normally close the gas vent V. The safety valve20has a discharge port opposing the gas guiding passage of the gas duct79.

When the pressure in the first battery2increases to exceed a predetermined threshold pressure, the safety valve20opens the gas vent V, so that high pressure gas with a high temperature of, for example, 500° C. inside the first battery2issues upward from the gas vent V and the discharge port toward the gas duct79.

At that time, because the high pressure gas issuing from the discharge port is guided by the gas duct79, the flow of the high pressure gas is deflected in the front and rear direction. This can prevent, even if the pressure in the first battery2increases so that high pressure gas issues from the discharge port, the issuing high pressure gas from contacting to the resin mold package76.

The first battery2is provided at its top wall of the frame with metal positive and negative terminals21and22symmetrically arranged thereon with respect to the safety valve20in the longitudinal direction. These terminals21and22project outward from the top wall toward the power-transfer circuit module10.

The positive terminal21is fixedly and closely contacted onto the cooling fins741of the heatsink74, which allows good electrical conduction between the positive terminal21and the heatsink74. Similarly, the negative terminal22is fixedly and closely contacted onto the cooling fins751of the heatsink75, which allows good electrical conduction between the negative terminal22and the heatsink75. This makes it possible to establish electrical connection between the first battery2and the power-transfer circuit module10.

The heatsinks74and75(cooling fins741and751) are made of a metallic material having high heat capacity and a good thermal conductivity so as to be formed to have a wide radiating surface.

For this reason, even if high pressure gas issuing from the discharge port of the safely valve20, the high pressure gas collies with each of the heatsinks74and75so as to be cooled thereby. This can prevent the first and second card modules72and73and the controller chip8from being thermally affected.

Let us assume that the power-transfer circuit module10is mounted on the top of the first battery2so that the fins710are fixedly and closely contacted onto each of a positive terminal21and a negative terminal22.

In this assumption, high pressure gas issuing from the discharge port of the safely valve20collies with the base plate71, whose heat capacity is grater than that of each of the heatsinks74and75, so as to be more cooled thereby. In this assumption, therefore, the gas duct79can be omitted.

In this assumption, however, it will be necessary to add:

a first bus bar for connecting between the positive terminal21of the first battery2and the heatsink74serving as an electrode of the circuit module10; and

a second bus bar for connecting between the negative terminal22of the first battery2and the heatsink75serving as an electrode of the circuit module10.

In the structure of the battery module101, the heatsinks74and75serve as heatsinks for cooling the first battery2.

Note that a first metal member with a plurality of fins for cooling the power-transfer circuit module10can be individually provided in a space between the power-transfer circuit module10and the outer top wall surface of the first battery2such that the first metal member is closely contacted onto the power-transfer circuit module10. Similarly, a second metal member with a plurality of fins for cooling the first battery2can be individually provided in the space between the power-transfer circuit module10and the outer top wall surface of the first battery2such that the second metal member is closely contacted onto the outer top wall surface of the first battery2. In this case, the first and second metal members are set to have an identical potential, or they can be electrically separated to be isolated from each other.

The box-shaped frame of the first battery2has a pair of first and second sidewalls in the width direction of the vehicle, and the box-shaped battery cover15has a pair of corresponding first and second sidewalls in the width direction of the vehicle. The outer surfaces of the first and second sidewalls of the first battery's frame are nearly or closely contacted on the inner surfaces of the corresponding first and second side walls of the battery cover15, respectively (seeFIG. 4).

The box-shaped frame of the first battery2also has a pair of third and fourth sidewalls in the front and rear direction of the vehicle, and the box-shaped battery cover15has a pair of corresponding third and fourth sidewalls in the front and rear direction of the vehicle. The outer surfaces of the third and fourth sidewalls of the first battery's frame are located to face the inner surfaces of the corresponding paired sidewalls of the battery cover15with spaces C1and C2, respectively (seeFIG. 5).

As illustrated inFIG. 5, the spaces provide cooling-air passages that allow flow of wind caused by the running vehicle and/or forced cooling air therethrough.

The third sidewall of the battery cover15is formed at its lower portion with a cooling-air inlet port121airtightly coupled to a downstream end of a cooling-air guiding duct33made of, for example, a suitable resin to be communicated therewith. The fourth sidewall of the battery cover15is formed at its lower portion with a cooling-air discharge port122communicably coupled to the inside of the engine compartment150. The cooling-air discharge port122is substantially arranged opposing the cooling-air inlet port121, and permits cooling-air to be discharged therethrough into the inside of the engine compartment150.

An upstream end of the cooling-air guiding duct33is so located at the front side in the engine compartment150as to be directed toward the forward direction of the vehicle. This allows wind caused by the running vehicle to be taken into the cooling-air guiding duct33via its upstream end. A cooling-fan unit200is attached to the cooling-air guiding duct33so as to be airtightly communicated with the duct33.

FIG. 6schematically illustrates an example of the structure of the cooling-fan unit200.

As illustrated inFIG. 6, the cooling-fan unit200is equipped with a centrifugal fan114with an air inlet port and an air outlet port. The cooling-air guiding duct33is composed of an upstream portion131and a downstream portion132. A downstream end of the upstream portion131is airtightly coupled to the inlet port of the centrifugal fan114to be communicated therewith. An upstream end of the downstream portion132is airtightly coupled to the centrifugal fan114to be communicated therewith.

The air-cooling fan unit200is equipped with a bypass duct115is airtightly coupled between the upstream portion131and the downstream portion132to bypass the centrifugal fan114. The air-cooling fan unit200is equipped with a motor M operative to drive the centrifugal fan114.

The air-cooling fan unit200is equipped with a check damper116consisting of a plurality of, for example, two valve elements116aand116brotatably attached to the inlet of the bypass duct115in an axial direction of the inlet of the bypass duct115by means of, for example, resin hinges, respectively. The valve elements116aand116bare so designed in size and location that, when fully closed, the inlet of the bypass duct115can be fully closed.

Specifically, when the upstream portion131of the cooling-air guiding duct33has a positive pressure with respect to the downstream portion132thereof, the differential pressure permits the valve elements116aand116bto open. In contrast, when the upstream portion131of the cooling-air guiding duct33has a negative pressure with respect to the downstream portion132thereof, the differential pressure permits the valve elements116aand116bto close.

The motor M is electrically connected to the controller8. At least one temperature sensor (not shown) is provided for measuring a temperature of the first battery2and/or the power-transfer circuit module10and for sending measurement data indicative of the measurement of the temperature to the controller8.

Specifically, when determining that the temperature of the first battery2and/or the circuit module10is higher than a predetermined threshold temperature, the controller8drives the centrifugal fan114. The driven centrifugal fan114allows forced cooling air to flow into the downstream portion132of the cooling-air guiding duct33so as to enter into the battery cover15via the cooling-air inlet port121.

When determining that the temperature of the first battery2and/or the circuit module10is equal to or lower than the predetermined threshold temperature, the controller8does not drive the centrifugal fan114. This allows, when strong wind is caused by the vehicle running, the wind to flow into the downstream portion132of the cooling-air guiding duct33via the upstream portion131so as to enter into the battery cover15via the cooling-air inlet port121.

As described above, the simple structure of the air-cooling fan unit200allows, if need arises, the wind caused by the vehicle running and/or the forced cooling air to flow into the battery cover15. The wind/forced cooling air flows upward via the space C1while cooling the third sidewall of the first battery2, and flows via the spaces of each of the cooling fins710,741, and751the metal gas duct79while cooling the base plate71, and the heatsinks74and75with little pressure loss. This allows both the first battery2and the power-transfer circuit module10to be effectively cooled.

In other words, the spaces between the cooling fins741and751provide a common cooling passage for both of the first battery2and the power-transfer circuit module10, making it possible to reduce the battery module101in size.

Then, the wind/forced cooling air flows via the space C2while cooling the fourth sidewall of the first battery2, and thereafter, is discharged into the engine compartment150via the air discharge port122. The transfer of the wind/forced cooling air in the battery cover15allows the first battery2and the power-transfer circuit module10to be cooled.

Note that the valve elements116aand116bof the check damper116can be fixedly supported by metal shafts rotatably attached to the inlet of the bypass duct115in the axial direction of the inlet. In addition, note that, as the air-cooling fan unit200, an air-cooling fan unit having another structure can be adopted, and that the cooling air issued from the air-cooling fan unit200can be used for cooling another in-vehicle device.

In order to more increase cooling effect on the first battery2, the outer wall surfaces of the third and fourth sidewalls of the first battery's frame can be formed with cooling fins projecting in the corresponding spaces (cooling-air passages) C1and C2therefrom.

As described above, the multiple power supply apparatus PA according to the first embodiment includes the integrated battery assembly100configured such that:

the second battery4is arranged closely adjacent to the battery module101; and

the battery module101is composed of the first battery2on which the power-transfer module100is integrally mounted.

The configuration of the integrated battery assembly100allows the total size of the integrated battery assembly100to be compact as compared with a configuration in which a first battery, a second battery, and a power-transfer circuit module are distributedly arranged from each other.

In addition, the configuration of the integrated battery assembly100can simplify wiring between the second battery4and the battery module101and between the first battery2and the power-transfer circuit module10. This makes it possible to reduce wiring length between the second battery4and the battery module101and between the first battery2and the power-transfer circuit module10.

Preferably, as described in the first embodiment, the second battery4and the battery module101are integrally coupled to each other with the first and second bus bars16and17without using cables. This is because, for example, bus bars normally have a bar shape in its lateral cross section, so they are lower in resistance than cables having a circular shape in its lateral cross section.

Accordingly, in the first embodiment, it is possible to reduce power loss in resistance of the wiring between the second battery4and the battery module101and between the first battery2and the power-transfer circuit module10. In the first embodiment, electrical insulation of the wiring can be easily ensured.

In the first embodiment, the second battery4is mounted on the top of the battery cover15covering the battery module101. For this reason, it is easy to carry out visual check of the second battery4and replace it; this second battery4has a comparatively short lifetime and easily reduces the battery electrolyte.

In the first embodiment, the power-transfer circuit module10is fixedly mounted on the top of the first battery2. For this reason, it is possible to couple the power-transfer module10and the first battery2by the most direct way as compared with cases where the power-transfer circuit and the first battery are separately arranged from each other.

For example, as described above, the positive and negative terminals21and22are directly contacted onto the heatsinks74and75of the power-transfer circuit module10, which allow good electrical conduction between the positive and negative terminals21and22and the first and second card modules72and73via the heatsinks74and75, respectively. This electrical connection between the power-transfer circuit module10and the first battery2can eliminate cables for connection therebetween as much as possible.

Thus, in the first embodiment, it is possible to reduce, in weight and size, wiring members for electrical connections between the power transfer circuit module10and the first battery2, thereby reducing them in cost.

In the first embodiment, the integrated battery assembly100can be installed in the engine compartment150of the vehicle while reducing the number and length of routings of cables for electrical connections among the first battery2, the second battery4, and the power-transfer circuit module10. This can reduce, as much as possible, the number of cables located close to high-temperature devices and/or rotating members located in the engine compartment150, thereby reducing the amount of protective layers of the cables.

The reduction of the number and length of routings of cables for electrical connections among the first battery2, the second battery4, and the power-transfer circuit module10allows reduction of the burden required to address brakes in some of the cables to be unavoidable in the event of a collision.

These effects set forth above allow the multiple power supply apparatus PA to be easily installed in compact vehicles that are subjected to restriction on increase in weight and space.

Particularly, in the multiple power supply apparatus PA, the first battery2, the second battery4, and the power-transfer circuit module10can be electrically connected to each other using bus bars containing heatsinks while they are integrally clamped to each other without relative movement thereamong. This can contribute the effects obtained by the multiple power supply apparatus PA described hereinbefore.

In the first embodiment, the first battery2is capable of storing high electrical energy as compared with conventional lead batteries. For this reason, it is necessary to improve impact resistance of the first battery2in order to guard the first battery2from destruction in the event of a crash.

From this viewpoint, in the first embodiment, the second battery4is mounted on the power-transfer circuit module10below which the first battery2is arranged. Therefore, in the event of a frontal crash, the impact due to the frontal crash can be absorbed by deformation of the second battery4whose stored electrical energy is lower than that of the first battery2. Thereafter, the remaining impact can be absorbed by deformation of the power-transfer circuit module10before it acts on the first battery2.

Thus, in the first embodiment, it is possible to improve impact resistance of the first battery2, thereby reducing the possibility of the first-battery destruction occurring even in the even of a crash.

In particular, in the first embodiment, even if the safety valve20opens the gas vent V so that high pressure gas inside the first battery2issues upward from the gas vent V and the discharge port, the power-transfer circuit module10mounted on the top of the first battery2can prevent the high pressure gas from issuing upward therethrough.

Specifically, because the gas duct79of the power-transfer circuit module10can deflect the flow of the high-pressure gas in the longitudinal direction, the safety of the multiple power supply apparatus PA can be improved.

In the first embodiment, the second battery4, the power-transfer circuit module10, and the first battery2are layered in this order from highest to lowest to constitute the integrated battery assembly100. For this reason, upon installation of the layered battery assembly100on the bottom of the vehicle body in the engine compartment150, a horizontal space required to install the assembly100on the bottom of the vehicle body in the engine compartment150can be considerably reduced.

Therefore, even if the layered battery assembly100is installed on the bottom of the vehicle body in the engine compartment150, it is possible to secure the freedom of arrangement of other in-vehicle components required to be installed in the engine compartment150.

The power-transfer circuit module10is fixedly mounted on the top wall of the first battery2outside the vehicle to constitute the battery module101, and thereafter, the battery module101is installed on the bottom of the vehicle body in the engine compartment150. This makes it easy to install the battery module101in the engine compartment150as compared with random installation of the first battery2and the power-transfer circuit module10in the engine compartment150.

The metal heatsinks74and75are arranged between the first battery2and the first and second card modules72and73, respectively. This arrangement can prevent heat caused by the first and second card modules72and73from being transferred to the first battery2. Specifically, each of the heatsinks74and75can cool a corresponding one of the card modules72and73and the first battery2.

Therefore, it is possible for the heatsinks74and75to thermally isolate the first battery2, which is required to limit an increase in temperature, from the power-transfer circuit module10. This can prevent heat caused by the power-transfer circuit module10from adversely affecting on the first battery2.

In the first embodiment, the heatsinks74and75are designed to serve as bus bars for establishing electrical connection between the first battery2and the power-transfer circuit module10. This can simplify the structure of the power-transfer circuit module10, and reduce in weight of the power-transfer circuit module10.

The battery cover15of the first embodiment provides a plurality of cooling passages between the battery module101and the cover15, and can electrically and mechanically protect the battery module101. The battery cover15can be individually mounted on the bottom of the vehicle body in the engine compartment150independently of the battery module101.

As illustrated inFIG. 2, in the installation state of the integrated battery assembly100on the bottom11of the vehicle body, the widths of the second battery4in the respective side to side direction and longitudinal direction are longer than those of the battery module101in the respective side to side direction and longitudinal direction. This makes it possible to prevent the horizontal impact caused by a crash from being applied on the power-transfer circuit module10and the first battery2.

FIG. 7schematically illustrates an example of the structure of an integrated battery assembly100A according to a first modification of the first embodiment.

As illustrated inFIG. 7, the integrated battery assembly100A is installed in the engine compartment150such that the second battery4and the battery module101are both located adjacent to a left side panel18of the engine compartment150. This allows the battery module101to be arranged at the back of the second battery4.

InFIG. 7, the second battery4is directly mounted on one outer wall surface of the first battery2corresponding to the outer top wall surface in the first embodiment, but it can be mounted on the battery cover15with which the battery module101is covered. The integrated battery assembly100A is fixed to the vehicle body with the use of, for example, the clamping members13and14in the same manner as the first embodiment, but it can be fixed to the vehicle body with the use of another fixing mechanism.

In the first modification, the second battery4is arranged at the front side of the battery module101. This allows, in the event of a frontal collision, the second battery4to protect the battery module101. Thus, it is possible to improve the safety of the first battery2against a frontal crash.

As well as the first embodiment, the width of the second battery4in the width direction is longer than that of the battery module101in the width direction. This makes it possible to prevent the horizontal impact caused by a crash from being applied on the power-transfer circuit module10and the first battery2, thereby more improving the safety of the first battery2against a lateral collision.

Note that the first battery2has a predetermined allowable maximum operation temperature lower than that of the second battery4. For this reason, as illustrated between parentheses in FIG.,7, when the engine EN is located at the rear side of the engine compartment150, the second battery4can be arranged closer to the engine EN than the first battery2. This allows the first battery2to be thermally protected against heat generated by the engine EN.

FIG. 8schematically illustrates an example of the structure of an integrated battery assembly100B according to a second modification of the first embodiment.

As illustrated inFIG. 8, the integrated battery assembly100B is installed in the engine compartment150such that the second battery4is located adjacent to the left side panel18of the engine compartment150, and the battery module101is located at the inner side of the second battery4in the width direction.

InFIG. 8, the second battery4is directly mounted on one outer wall surface of the first battery2corresponding to the outer top wall surface, but it can be mounted on the battery cover15with which the battery module101is covered. The integrated battery assembly100B is fixed to the vehicle body with the use of, for example, the clamping members13and14in the same manner as the first embodiment, but it can be fixed to the vehicle body with the use of another fixing mechanism.

In the second modification, the second battery4is arranged at the outer side of the battery module101in the side to side direction. This allows, in the event of a lateral collision, the second battery4to protect the battery module101. Thus, it is possible to improve the safety of the first battery2against a lateral crash.

As well as the first embodiment, the length of the second battery4in the longitudinal direction is longer than that of the battery module101in the longitudinal direction. This makes it possible to prevent the impact caused by a frontal crash from being applied on the power-transfer circuit module10and the first battery2, thereby more improving the safety of the first battery2against a frontal collision.

In the first embodiment, the power-transfer circuit module10is fixedly mounted on the top of the first battery2, but it can be fixedly mounted on the bottom11of the vehicle body with the use of any one of supporting members.

FIGS. 9 and 10schematically illustrate an example of the structure of a battery module101A according to a third modification of the first embodiment.

As illustrated inFIG. 9, a battery cover15A is made of metal. A power-transfer circuit module10A of the battery module101A is directly mounted on the top of the first battery2so that the fins710are fixedly and closely contacted onto each of the positive terminal21and negative terminal22.

The cooling fins741and751of the heatsinks74and75are contacted to an inner surface of a top wall of the battery cover15A via an insulating seat (not shown). This allows the battery cover15A to be closely adjacent to the heatsinks74and75while keeping electrical insulating between the battery cover15A and each of the heatsinks74and75.

The power-transfer circuit module10A has widths in the respective width direction and longitudinal direction that are longer than those of the first battery2in the respective width direction and longitudinal direction.

The power-transfer circuit module10A is formed at, for example, its base plate71with a slit29that ensures a space that surrounds the safety valve20.

Other parts of the battery module101A of the third modification are substantially identical to those of the battery module101.

In the configuration of the battery module101A, even though high pressure gas inside the first battery2issues upward from the gas vent V and the discharge port of the safety valve20, the battery cover15A can prevent the high pressure gas from flowing toward the second battery4via the battery cover15A.

The battery cover15A serves as a cooling metal member together with the heatsinks74and75for cooling the power-transfer circuit module10A, making it possible to improve the cooling efficiency of the power-transfer circuit module10A.

The widths of the power-transfer circuit module10A in the respective width direction and longitudinal direction are longer than those of the first battery2in the respective width direction and longitudinal direction. For this reason, it is possible to prevent the impact caused by a frontal or horizontal crash from being applied on the first battery2.

In the third modification, the metal battery cover15A can serve as a ground bus bar electrically connected to a ground terminal of the first battery2or the power-transfer circuit module10A. Either the metal members74,75, or71can be selectively connected to the battery cover15A or contacted thereto via an insulating sheet with high thermal conductivity.

FIG. 11schematically illustrate an example of the structure of a battery module101B according to a fourth modification of the first embodiment.

As illustrated inFIG. 11, a power-transfer circuit module10B is provided with a power-transfer circuit module10′ substantially equivalent to the power-transfer circuit module10, and a plurality of first cooling fins400fixedly mounted on the heatsinks74and75(cooling fins741and751). The first cooling fins400project from the heatsinks74and75downward at regular intervals in the side to side direction of the vehicle. First spaces S1formed between the individually adjacent first cooling fins400provide lower cooling-air passages in the longitudinal direction of the vehicle.

The first cooling fins400are mounted onto the positive and negative terminals21and22of the first battery21for cooling the first battery21.

The power-transfer circuit module10B is also provided with a plurality of second cooling fins500fixedly mounted on the base plate71(cooling fins710). The second cooling fins500are operative to cool components inside the power-transfer circuit module10B.

The second cooling fins500project from the base plate71upward at regular intervals in the width direction of the vehicle. Second spaces S2formed between the individually adjacent second cooling fins500provide upper cooling-air passages in the longitudinal direction of the vehicle.

A battery cover15B made of metal covers the top portion of the first battery2and the power-transfer circuit module10B such that an inner top wall surface of the battery cover15B is contacted to the second cooling fins500via, for example, an insulating sheet. The battery cover15B is arranged to keep a space S3between one sidewall thereof and the power-transfer circuit module15B. The space S3is communicated with the first and second spaces S1and S2, which provides a circulating cooling air passage in the battery cover15B.

In the fourth modification, the other sidewall of the battery cover15B opposing the one sidewall is formed at its lower end with a cooling-air inlet port121A airtightly coupled to a downstream end of a cooling-air guiding duct33A made of, for example, a suitable resin to be communicated therewith. Specifically, in the fourth modification, the cooling-air guiding duct33A is located to face the first spaces S1and the first cooling fins400.

Other parts of the battery module101B of the fourth modification are substantially identical to those of the battery module101.

When cooling air caused by the vehicle running or the air-cooling fan unit200enters into the battery cover15B via the cooling-air inlet port121A, the cooling air entirely flows through the first spaces S1toward the rear side while cooling the first cooling fins400. Thereafter, the cooling air further flows upward through the third space S3, and reversely flows toward the front side through the second spaces S2while cooling the second cooling fins500.

Specifically, in the fourth modification, the battery cover15B can provide the circulating cooling passage surrounding the power-transfer circuit module10′ in the vertical direction. This allows:

the first cooling fins400to be located between the circuit module10′ and the first battery2to cool both of them; and

the second cooling fins500to be located between the battery cover15B and the circuit module10′ to cool mainly the circuit module10′.

Thus, the number and the area of the first cooling fins400can be different from those of the second cooling fins500. This allows the cooling capacity of the first cooling fins400to be higher than that of the second cooling fins500, making it possible to reduce in size the second cooling fins500while keeping high heating capacity of the first cooling fins400.

The circulating cooling passage allows cooling air caused by the vehicle running or the air-cooling fan unit200to be entirely used to cool both the first battery2and the circuit module10B.

The battery cover15B can mechanically protect the circuit module10B.

The battery cover15B and the circuit module10B can protect the first battery2against an impact applied to the battery module101B from the upper side thereof. Even though high pressure gas inside the first battery2issues upward from the gas vent V and the discharge port of the safety valve20, the battery cover15B and the circuit module10B can prevent the high pressure gas from flowing toward the second battery4via the battery cover15B.

Note that, in the fourth modification, the widths of the power-transfer circuit module10A in the respective width direction and longitudinal direction can be set to be longer than those of the first battery2in the respective width direction and longitudinal direction. This structure can block, onto the first battery2, the application of the impact caused by a frontal or horizontal crash.

The cooling-air guiding duct33and the battery cover15(15A,15B) can be designed at least partly by a plate-like metal member coupled in good heat transfer relation to at least one of the base plate71, and the heatsinks74and75. This modification allows cooling effect on the first battery2and/or the circuit module10(10A,10B) to be improved.

For example, part of the cooling-air guiding duct33, which is located close to the circuit module10(10A,10B) or the first battery2so that the temperature sensitively increases, can be formed using a plate-like metal member.

Part of the cooling-air guiding duct33, which is located close to the circuit module10(10A,10B) or the first battery2, can serve as part of the battery cover15(15A,15B). The part of the cooling-air guiding duct33serving as part of the battery cover can be integrally formed to the heatsinks74and75, or can be contacted thereonto, which makes it possible to improve the cooling capacity of the heatsinks74and75.

At least part of the cooling-air guiding duct33can be configured by part of the metal vehicle body. For example, part of the metal vehicle body to which no solar radiation is directly received can be used as the part of the cooling-air guiding duct33.

For example, a gutter like metal member is mounted on part of the metal vehicle body to provide a cooling-air guiding duct. Cables and/or wires for electrical connections between the battery module101(101A,101B) and the generator1and/or the electrical loads5can be routed in the cooling-air guiding duct33.

Second Embodiment FIG.12schematically illustrates an example of the arrangement of a multiple power supply apparatus PA1according to a second embodiment of the present invention.

Similarly to the first embodiment, the multiple power supply apparatus PA1includes an integrated battery assembly. The structure of the multiple power supply apparatus PA1is substantially identical to that of the multiple power supply apparatus PA according to the first embodiment.

Thus, like reference characters are assigned to like parts in the multiple power supply apparatuses according to the first and second embodiments, and therefore, descriptions of the structure of multiple power supply apparatus PA1are omitted.

As illustrated inFIG. 12, the multiple power supply apparatus PA1is installed beforehand in an engine compartment150of a vehicle. In the engine compartment150, the engine EN and the generator1are also installed beforehand. Some of the electrical loads5are located in a vehicle compartment800of the vehicle located at the rear side of the engine compartment150.

As illustrated inFIG. 12, the engine EN is located close to the frond end of the vehicle body, and the generator1is located at the left rear side of the engine EN.

In the front and left direction, the integrated battery assembly100is located between the generator1and some of the electrical loads5.

Specifically, the first battery2, the power-transfer circuit module10, and the second battery4are so fixedly adjacent to the left rear corner of the engine compartment150as to align with each other parallel to the left side panel of the engine compartment150in this order from the front side to the rear side.

One sidewall of the second battery4opposing the left side panel of the engine compartment150projects toward the left side panel as compared with a corresponding one sidewall of each of the first battery2and the power-transfer circuit module10opposing the left side panel.

Note that the power-transfer circuit module10and the second battery4can be so fixedly located at one of the remaining corners of the engine compartment150as to align with each other substantially parallel to a corresponding side panel of the engine compartment150.

The generator1and the first battery2are electrically connected with cables400, and the second battery4and the electrical loads4are electrically connected to cables500.

Input terminals of the first battery2(see reference characters21and22inFIG. 4) are electrically connected to corresponding main electrodes of the power-transfer circuit module10(see reference characters720and730inFIG. 3) with bus bars600(see heatsinks74and75serving the bus bars inFIG. 3).

A high-side output terminal (see reference character71inFIG. 4) and a low side output terminal are electrically connected to positive and negative terminals of the second battery4(see reference characters41and42inFIG. 2) with bus bars700(see reference characters16and17inFIG. 2).

FIG. 13schematically illustrates electrical connections among the first battery2, the power-transfer circuit module10, and the second battery4with the use of the cables400and500, and the bus bars600and700.

Specifically, the cable500corresponding to the second power supply line6is electrically connected to some of the electrical loads5located in a vehicle compartment800. This allows power to be supplied from the multiple power supply apparatus PA1to some of the electrical loads5located in the vehicle compartment800.

As described above, in the second embodiment, the first battery2required to connect to the generator1is arranged closer to the generator1than other components10and4of the apparatus PA1. Between the generator1and some of the engine loads5, the first battery2, the power-transfer circuit module10, and the second battery4are arranged in this order from the front side to the rear side. The second battery4required to connected to some of the electrical loads5is arranged closer to some of the electrical loads5than other components2and10of the apparatus PA1.

The length of wiring members required for electrical connections among the components1,2,10,4, and5can be therefore reduced.

Accordingly, it is possible to reduce, in weight, the wiring members and reduce spaces required to route the wiring members. This results in that resistance loss of the wiring members are reduced, thereby improving fuel consumption of the vehicle.

In addition, one sidewall of the second battery4opposing the side panel of the left side panel of the engine compartment150projects toward the left side panel as compared with one sidewall of each of the first battery2and the power-transfer circuit module10opposing the left side panel. Thus, it is possible to, in the event of a left-side crash, reduce the damage caused by the left-side crash to the first battery2. Note that, as described above, the circuit module10can be mounted on the top of the first battery2.

FIG. 14schematically illustrates an example of the arrangement of a multiple power supply apparatus PA2according to a first modification of the second embodiment of the present invention.

As illustrated inFIG. 14, the multiple power supply apparatus PA2is installed beforehand in an engine compartment150of a vehicle. In the engine compartment150, the engine EN and the generator1are also installed beforehand. Some of the electrical loads5are located in a vehicle compartment800of the vehicle.

As illustrated inFIG. 14, the engine EN is located close to the frond end of the vehicle body, and the generator1is located at the left rear side of the engine EN.

In the front and rear direction, the integrated battery assembly100is located between the generator1and some of the electrical loads5.

Specifically, the second battery4, the power-transfer circuit module10, and the first battery2are so fixedly adjacent to the left rear corner of the engine compartment150as to align with each other substantially parallel to the side to side direction in this order from the leftmost side to the right side.

One sidewall of the second battery4opposing the frond end of the vehicle body projects toward the front end as compared with a corresponding one sidewall of each of the first battery2and the power-transfer circuit module10opposing the front end.

Other parts of the multiple power supply apparatus PA2are substantially identical to those of the multiple power supply apparatus PA1.

As described above, in the first modification of the second embodiment, the first battery2required to connect to the generator1is arranged closer to the generator1than other components10and4of the apparatus PA2. Between the generator1and some of the engine loads5, the second battery4, the power-transfer circuit module10, and the first battery2are arranged in this order from the leftmost side to the right side.

The length of wiring members required for electrical connections among the components1,2,10,4, and5can be therefore reduced. This makes it possible to reduce, in weight, the wiring members and reduce spaces required to route the wiring members. This results in that resistance loss of the wiring members are reduced, thereby improving fuel consumption of the vehicle.

In addition, one sidewall of the second battery4opposing the front side of the vehicle body projects toward the front end as compared with a corresponding one sidewall of each of the first battery2and the power-transfer circuit module10opposing the front end. Thus, it is possible to, in the event of a frontal crash, reduce the damage caused by the frontal crash to the first battery2. Note that, as described above, the circuit module10can be mounted on the top of the first battery2.

As described above, the multiple power supply apparatuses PA1and PA2according to the second embodiment and its first modification can obtain substantially the same effects as the first embodiment.

Especially, the multiple power supply apparatuses PA1and PA2can be easily installed in compact vehicles that are subjected to restriction on increase in weight and space.

In the second embodiment and its first modification, the circuit module10and the first battery2can be separately arranged from each other in a vehicle.

Third Embodiment

FIG. 15schematically illustrates an example of the structure of the power-transfer circuit module10C of a multiple power supply apparatus PA3.

The circuit configuration of the multiple power supply apparatus PA3is substantially identical to that of the multiple power supply apparatus PA according to the first embodiment (seeFIG. 1).

Thus, like reference characters are assigned to like parts in the multiple power supply apparatuses according to the first and third embodiments, and therefore, descriptions of the structure of multiple power supply apparatus PA3are omitted.

As illustrated inFIG. 15, the power-transfer circuit module10C includes the metal base plate71, the double-sided electrode first and second card modules72and73each integrated with a power MOS transistor, the controller8, the heatsinks74and75, the resin mold package76, and the insulating sheet77. The lead electrodes (control electrodes) of the first and second card modules72and73are electrically connected to corresponding pins of the controller8, respectively.

Specifically, as compared with the structure of the power-transfer circuit module10, the gas duct79is removed from the power-transfer circuit module10C.

FIG. 16schematically illustrates an example of the structure of a battery module101C constructed by the power-transfer circuit module10C and the first battery2before installation on the bottom of the vehicle body, which is viewed from the bottom side of the vehicle toward the top side.FIG. 17schematically illustrates the structure of the battery module101C illustrated inFIG. 16, which is viewed from one side (left side) of the vehicle toward the other side (right side).

Note that the left side and right side are determined with reference to the forward travel direction of the vehicle.

In the first embodiment, the forth sidewall of the battery cover15extends toward the bottom11of the vehicle body.

In contrast, in the third embodiment, a corresponding fourth sidewall of a resin battery cover15C covers only the top portion of the first battery2with a space C2A between the fourth sidewall of the battery cover15C and the corresponding fourth sidewall of the first battery2.

Like the first embodiment, the outer surface of the third sidewall of the first battery's frame is located to face the inner surface of the third sidewall of the battery cover15C with a space C1A, which is larger than the space C1(seeFIG. 17).

The third sidewall of the battery cover15C is formed at its lower portion with a cooling-air inlet port121airtightly coupled to the downstream end of the cooling-air guiding duct33.

The space C1A allows the power-transfer circuit module10C to be located between the third sidewall of the battery cover15C and the corresponding third sidewall of the first battery2above the cooling-air inlet port121. Specifically, the power-transfer circuit module10C is arranged such that:

the cooling fins710of the base plate71are contacted onto the inner surface of the third sidewall of the battery cover15C;

the cooling fins741and751are contacted onto the third sidewall of the first battery2;

top end surfaces of the cooling fins741and751are flush with the outer top wall surface of the first battery2;

the cooling fins710,741, and751project upward at regular intervals in the width direction of the vehicle; and

the spaces formed between the cooling fins710,741, and751extend in parallel to the vertical direction (top and bottom direction) of the vehicle.

The arrangement of the power-transfer circuit module10C allows the cooling air passages (spaces between the cooling fins710,741, and751) to extend in the top and bottom direction so as to communicate at their bottom ends with the cooling-air inlet port121.

The top wall portion of the battery cover15C is so arranged as to provide a space C3between the inner surface of the top wall portion of the battery cover15C and the outer top wall surface of the first battery2. The space C3is communicated with the space C1A via the spaces between the cooling fins710,741, and751. The space C3is also communicated with the space C2A.

As illustrated inFIG. 17, the first battery2is provided with the safety valve20so mounted on the outer top wall surface of the first battery2as to normally close the gas vent V. The battery module101C has a gas duct79A with, for example, a substantially half-cylindrical shape. The gas duct79A is fixed at its outer peripheral surface to the inner top wall surface of the battery cover15C such that a gas guiding passage formed inside the gas duct79A is parallel to the front and rear direction of the vehicle. The safety valve20has a discharge port opposing the gas guiding passage of the gas duct79A.

The first battery2is provided at its top wall of the frame with metal positive and negative terminals21A and22A. The positive and negative terminals21A and22A are symmetrically arranged on the top wall with respect to the safety valve20in the longitudinal direction.

For example, each of the positive and negative terminals21A and21B has a heatsink and an inner surface opposing an inner surface of the other thereof. The inner surface of each of the positive and negative terminals21A and21B is formed with a plurality of cooling fins projecting therefrom toward the other thereof. The positive terminal21A is electrically connected to the cooling fins741via a bus bar, and the negative terminal21B is electrically connected to the cooling fins751of the heatsink75via bus bars1000. This allows electrical connection between the first battery2and the circuit module10C.

Note that, the heatsink of the positive terminal21A and the heatsink74can be integrated with each other in the form of L, and the heatsink of the positive terminal21B and the heatsink75can be integrated with each other in the form of L. This can eliminate bus bars for respective electrical connections between the positive and negative terminals21A and22A and the heatsinks74and75. The battery cover15C can be designed as a metal battery cover, and in this case, the negative terminal22A and the heatsink75can be contacted to the vehicle body via the metal battery cover so as to be grounded.

In the third embodiment, even if the safety valve20opens the gas vent V so that high pressure gas inside the first battery20issues upward from the gas vent V and the discharge port, the gas duct79A can deflect the flow of the high pressure gas in the longitudinal direction. This allows the battery cover15C to have little influence on the high pressure gas.

As described above, the battery cover15C provides a plurality of cooling passages at the spaces of each of the cooling fins741,751, and710through which cooling air can flow.

The space C2A formed between the fourth sidewall of the battery cover15C and the top portion of the corresponding fourth side wall of the first battery2serves as a cooling-air discharge port122A.

Like the first embodiment, the cooling-fan unit200is attached to the cooling-air guiding duct33so as to be airtightly communicated with the duct33.

In the third embodiment, when cooling air is caused by the vehicle running or the air-cooling fan unit200, the cooling air enters into the space C1A inside the battery cover15C via the cooling-air inlet port121.

Then, the cooling air flows upward through the spaces (cooling-air passages) of the cooling fins710,714, and715while cooling the corresponding base plate71and the heatsinks74and75. Thereafter, the cooling air further flows toward the rear side through the space C3while cooling the positive and negative terminals21A and22A, and thereafter, the cooling air is discharged via the cooling-air discharge port122A downward along the fourth side wall of the first battery2.

Note that the power-transfer circuit module10C is located between the third sidewall of the battery cover15C and the corresponding third sidewall of the first battery2, but it can be fixedly mounted on the bottom11of the vehicle body with the use of any one of supporting members.

The power-transfer circuit module10C can be located between the first or second sidewall of the battery cover15C and the corresponding first or second sidewalls of the first battery2. This structure allows, in the event of one side collision corresponding to the first or second sidewall, the power-transfer circuit module10C to protect the first battery2.

In the third embodiment, when the battery cover15C is designed as a metal cover, the metal battery cover15C can serve as a ground bus bar electrically connected to a ground terminal of the first battery2or the power-transfer circuit module10C. At least one of the metal members74,75, and71can be selectively connected to the battery cover15C or contacted thereto via an insulating sheet with high thermal conductivity.

In the third embodiment, the cooling-air guiding duct33and the battery cover15C can be formed using a plate-like metal member coupled in good heat transfer relation to at least one of the metal members71,74and75. This modification allows cooling effect on the first battery2and/or the circuit module10C to be improved.

At least part of the cooling-air guiding duct33can be configured by part of the metal vehicle body. For example, a gutter like metal member is mounted on part of the metal vehicle body to provide a cooling-air guiding duct. Cables and/or wires for electrical connections between the battery module101C and the generator1and/or the electrical loads5can be routed in the cooling-air guiding duct33.

As described above, in the third embodiment and its modifications, the power-transfer circuit module10C is fixedly mounted on one of the sidewalls of the first battery2. For this reason, it is possible to couple the power-transfer circuit module10C and the first battery2by the most direct way as compared with cases where the power-transfer circuit and the first battery are separately arranged from each other.

This electrical connection between the power-transfer circuit module10C and the first battery2can eliminate cables for connection therebetween as much as possible.

Thus, it is possible to reduce, in weight and size, wiring members for electrical connections between the circuit module10C and the first battery2, thereby reducing them in cost.

In the third embodiment and its modifications, the power-transfer circuit module10C is mounted on the third sidewall of the first battery2facing the front side of the vehicle. In the event of a frontal crash, the impact due to the frontal crash can be therefore absorbed by deformation of the power-transfer circuit module10C before it acts on the first battery2. Thus, it is possible to improve impact resistance of the first battery2, thereby reducing the possibility of the first-battery destruction occurring even in the even of a crash.

In particular, in the third embodiment and its modifications, even if the safety valve20opens the gas vent V so that high pressure gas inside the first battery20issues upward from the gas vent V and the discharge port, the gas duct79can deflect the flow of the high pressure gas in the longitudinal direction.

The metal heatsinks74and75are arranged between the first battery2and the first and second card modules72and73, respectively. This arrangement can prevent heat caused by the first and second card modules72and73from being transferred to the first battery2. Specifically, each of the heatsinks74and75can cool a corresponding one of the card modules72and73and the first battery2.

Therefore, it is possible for the heatsinks74and75to thermally isolate the first battery2, which is required to limit an increase in temperature, from the power-transfer circuit module10C. This can prevent heat caused by the power-transfer circuit module10C from adversely affecting on the first battery2.

In the third embodiment and its modifications, the heatsinks74and75are designed to serve as bus bars for establishing electrical connection between the first battery2and the power-transfer circuit module10C. This can simplify the structure of the power-transfer circuit module10C, and reduce in weight of the power-transfer circuit module10C.

The battery cover15C of the third embodiment and its modifications provides a plurality of cooling passages, and can electrically and mechanically protect the first battery2. The battery cover15C can be individually mounted on the bottom of the vehicle body in the engine compartment150independently of the first battery2.

Fourth Embodiment

FIG. 18schematically illustrates an example of the structure of an air-cooled power system810installed in a vehicle according to a fourth embodiment of the present invention.

As illustrated inFIG. 18, the. air-cooled power system810is installed on, for example, the bottom of the vehicle body in the engine compartment150in the same manner as the first embodiment.

The air-cooled power system810includes a radiator fan820located at the front side of an engine EN installed on the bottom of the vehicle body in the engine compartment150. The air-cooled power system810also includes a motor830, a radiator840, a condenser850, an in-vehicle power device860, and a suction duct870.

For example, the radiator fan820has two or more blades BL attached to a shaft of the motor830, and the shaft of the motor830is arranged in parallel to the longitudinal direction of the vehicle. When the motor830is energized to rotate the shaft, the blades BL of the radiator fan820are rotated together with the motor shaft in a predetermined direction so as to suck air at the upstream of the fan820toward the engine EN for cooling it.

The radiator840is arranged at the front side of the radiator fan820and close thereto. The radiator840has a plate like radiating portion extending in orthogonal to the front and rear direction of the vehicle.

The condenser850is located at the front side of the radiator840. The condenser850is arranged such that a plate like condensing portion thereof is in parallel to the radiating portion of the radiator840. When air enters thereinto, the condenser850is operative to absorb heat from the air, thereby transferring it to the radiator840.

The radiator840works to cool the air transferred from the condenser850to output it toward the engine EN.

The in-vehicle power device860is arranged away from the radiator fan820.

In the fourth embodiment, as the in-vehicle power device860, the integrated battery assembly100according to one of the first to third embodiments and their modifications can be applied. Moreover, as the in-vehicle power device860, an integrated battery assembly having a single battery and a power-transfer circuit module operative to control charging current and discharging current to and from the single battery can be applied. Furthermore, an electric device that generates heat when energized can be applied as the in-vehicle power device860.

For example, the in-vehicle power device860has a first outer wall surface formed with a cooling-air inlet port860aairtightly coupled to a downstream end of a cooling-air guiding duct33A. The inlet port860ais directed toward the front end of the vehicle.

An upstream end of the cooling-air guiding duct33A is so located at the front side in the engine compartment150as to be directed toward the forward direction of the vehicle. This allows wind caused by the running vehicle to be taken into the cooling-air guiding duct33A via its upstream end.

The in-vehicle power device860has a cooling-air passage860bcommunicated with the cooling-air inlet port860a. For example, as described in each of the first to third embodiments, the cooling-air passage860bcan be configured as spaces formed by a plurality of cooling fins of a heatsink arranged to be contacted onto a battery and a power semiconductor element for cooling them. As the cooling structure of the in-vehicle power device860, one of the cooling structures described in the first to third embodiment and their modifications can be used.

The in-vehicle power device860also has a second outer wall surface opposing the first outer wall surface formed with a cooling-air discharge port860c. The cooling-air discharge port860cis communicated with the cooling-air passage860b.

The suction duct870is made of, for example, a suitable resin or a suitable metal plate, and has a substantially air hose. Specifically, the suction duct870has an upstream inlet871airtightly communicated with the cooling-air discharge port860c, a downstream outlet872located between the radiator840and the radiator fan820, and a duct portion873connecting between the inlet871and outlet872.

The suction duct870is operative to suck cooling air via the upstream inlet871into the duct portion873, and to transfer the sucked cooling air via the duct portion873toward the outlet872.

InFIG. 18, a reference character890shows a duct extending in the front and rear direction and containing the condenser850, the radiator840, the radiator fan820, and the motor830. The duct890works to guide airflow into the engine EN via the condenser850, the radiator840, and the radiator fan820.

A reference character880shows an upstream cooling-air passage formed among the condenser850, the radiator840, and the radiator fan820and extending in the longitudinal direction. The downstream outlet872of the suction duct870is for example directed toward the one side (left side or right side) or the rear side of the vehicle.

In other words, the downstream outlet872of the suction duct870is arranged such that the longitudinal direction of the suction duct870is undirected toward the front direction of the vehicle. This is because the downstream outlet872has little influence on dynamic pressure of airflow via the upstream cooling-air passage880.

Note that cooling air flowing out from the discharge port860cis entirely sucked into the suction duct870, but part of the cooling air flowing out from the discharge port860ccan be sucked into the suction duct870.

Operations of the air-cooled power system810will be described hereinafter.

When the motor830is energized to rotate the shaft, the blades BL of the radiator fan820are rotated together with the motor shaft. The rotation of the blades BL of the radiator fan820allows air located at the upstream cooling-air passage880to be rapidly sucked toward the engine EN for cooling it.

This allows strong airflow to be generated from the front side to the engine side, and the strong airflow causes a static pressure at the upstream cooling-air passage880to become a negative pressure.

Because the downstream outlet872of the suction duct870is located at the upstream cooling-air passage880, the negative pressure acts on the downstream outlet872of the suction duct870. Because the upstream inlet871of the suction duct870, the inlet port860a, and the cooling-air passage860bare directed toward the front end of the vehicle, the negative pressure permits air to be sucked via the inlet port860ainto the in-vehicle power device860.

The sucked air flows through the cooling-air passage860bwhile cooling the heatsink inside the device860to enter into the suction duct870, and the air entered into the suction duct870flows therethrough to be discharged into the upstream cooling-air passage880via the downstream outlet872of the suction duct870.

Moreover, even if the motor M is stopped so that the radiator fan820does not rotate, strong wind caused by the running vehicle is taken into the duct890and into the in-vehicle power device860via the inlet port860a.

The strong wind caused by the running vehicle flows through the condenser850, the radiator840, and the radiator fan820toward the engine EN.

This allows strong airflow to be generated from the front side to the engine side, and the airflow causes a static pressure at the upstream cooling-air passage880to become a negative pressure.

Accordingly, the negative pressure of the upstream cooling-air passage880allows air to be sucked via the inlet port860ainto the in-vehicle power device860. The sucked air flows through the cooling-air passage860bwhile cooling the heatsink. Thereafter, the sucked air flows through the suction duct870to be discharged into the upstream cooling-air passage880via the downstream outlet872of the suction duct870.

As described above, airflow forcibly caused by the radiator fan820and the motor830or by the vehicle running allows a static pressure at the upstream cooling-air passage880to become a negative pressure. The negative pressure permits air to be sucked into the in-vehicle power device860, making it possible for the sucked air to cool the heatsink of the in-vehicle power device860.

As a comparative example, the in-vehicle power device860may be located downstream of the radiator fan820in order to cool the in-vehicle power device860by air forcibly sucked by the radiator fan820.

In the comparative example, however, location of the in-vehicle power device860may be limited, and the presence of the in-vehicle power device860downstream of the radiator fan820may block the sucked air to be supplied to the engine EN. This may cause the engine EN to be insufficiently cooled. In particular, the location of the in-vehicle power device860downstream of the radiator fan820may make it difficult to prevent the in-vehicle power device860from increasing in temperature and to arrange the engine EN and the radiator fan820close to each other for increasing cooling performance.

In contrast, in the air-cooled power system810according to the fourth embodiment, it is possible to effectively cool the in-vehicle power device860without locating it downstream of the radiator fan820. It can be therefore clear of worry about the problems caused by the comparative example.

As another comparative example, a bypass duct may be provided for bypassing part of cooling air, which is forcibly sucked by the radiator fan820and blown out therefrom toward the downstream of the fan820, and for feeding the bypassed air into the in-vehicle power device860.

In another comparative example, in order to effectively catch the cooling air forcibly blown out from the fan820toward the downstream thereof and enter the caught air into the bypass duct, the bypass duct need to have an inlet with a wide opening to be arranged opposing the downstream surface of the fan820.

The wide opening of the inlet of the bypass duct however may cause a region downstream of the inlet through which no cooling air forcibly blown out from the fan820flows, which may reduce an effective cross-section area of a cooling-air passage through which the forcibly blowout cooling air flows. This may deteriorate the cooling of the engine EN.

In contrast, in the fourth embodiment, it is possible to cool the heatsink of the in-vehicle power device860without bypassing airflow blown out from the radiator fan820toward the engine EN. This can prevent cooling performance of the radiator fan820for cooling the engine EN and its peripheries from deteriorating.

As a first modification of the air-cooled power system810, the downstream outlet872of the suction duct870can be located upstream of the condenser850in the duct890.

FIG. 19schematically illustrates an example of the structure of an air-cooled power system810A according to a second modification of the fourth embodiment.

A main different point of the air-cooled power system810A from the air-cooled power system810is that the downstream outlet872of the suction duct870is located close to the radiator fan820at a downstream cooling-air passage895formed downstream of the fan820.

In addition, the cooling-air discharge port860cis entirely formed at the second outer wall surface of the in-vehicle power device860. The upstream end of the suction duct870is attached to the second outer wall surface such that the discharge port860cis airtightly communicated with the upstream inlet871of the suction duct870.

Because the radiator fan820can create high-velocity airflow toward the engine EN at the downstream cooling-air passage895, a static pressure at the downstream cooling-air passage895becomes a negative pressure. The negative pressure of the downstream cooling-air passage890acts on the he downstream outlet872of the suction duct870, which allows air to be sucked via the inlet port860ainto the in-vehicle power device860.

Accordingly, the heatsink inside the in-vehicle power device860can be effectively cooled by the sucked air flowing through the cooling-air passage860b.

FIG. 20schematically illustrates an example of the structure of an air-cooled power system810B according to a third modification of the fourth embodiment.

A first main different point of the air-cooled power system810B from the air-cooled power system810is that a cooling-air inlet port860ais formed at the second outer wall surface of the in-vehicle power device860A, and a cooling-air discharge port860cis formed at the first outer wall surface thereof.

The upstream end of the suction duct870is attached to the first outer wall surface of the in-vehicle power device such that the discharge port860cis airtightly communicated with the upstream inlet871of the suction duct870. The downstream outlet872of the suction duct870is located close to the radiator fan820at the upstream cooling-air passage880formed upstream of the fan820.

A second main different point of the air-cooled power system810B from the air-cooled power system810is to have a blowout duct910.

The blowout duct910is made of, for example, a suitable resin or a suitable metal plate, and has a substantially air hose. Specifically, the blowout duct910has an upstream inlet911located close to the radiator fan820at the downstream cooling-air passage895formed downstream of the fan820, a downstream outlet912airtightly communicated with the cooling-air inlet port860a, and a duct portion913connecting between the inlet911and outlet912.

Specifically, the upstream inlet911of the blowout duct910is so opened at the downstream cooling-air passage895as to be subjected to a dynamic pressure of airflow blown out from the fan820. This allows, when the radiator fan820is driven or wind caused by vehicle running is sucked by the radiator fan820so that cooling air is blown out from the radiator fan820, the blowout cooling air to enter into the blowout duct via the upstream inlet911. The cooling air flows through the duct portion913to enter into the cooling-air passage860bvia the outlet912and the inlet port860a. The cooling air flows through the cooling-air passage860bwhile cooling the heatsink inside the device860A to enter into the suction duct870via the discharge port860cand the inlet871.

The cooling air flows through the duct portion873to be discharged into the upstream cooling-air passage880via the downstream outlet872of the suction duct870.

As described above, in the air-cooled power system810B, cooling air (airflow) forcibly caused by the radiator fan820and the motor830or by the vehicle running is sucked into the blowout duct910so that the sucked cooling air flows into the in-vehicle power device860. This makes it possible to cool the heatsink of the in-vehicle power device860.

In the third modification, the downstream outlet872of the suction duct870is located close to the radiator fan820at the upstream cooling-air passage880formed upstream of the fan820. The upstream inlet911of the blowout duct910is located close to the radiator fan820at the downstream cooling-air passage895formed downstream of the fan820. The present invention is not limited to the arrangement. Specifically, the downstream outlet872of the suction duct870can be located close to the radiator fan820at the downstream cooling-air passage895, and the upstream inlet911of the blowout duct910can be located close to the radiator fan820at the downstream cooling-air passage895.

In the fourth embodiment and its first to third modifications, cooling air for cooling the in-vehicle power device860is formed by the suction duct870whose downstream outlet872is located at the upstream cooling-air passage880upstream of the radiator fan820or the downstream cooling-air passage895downstream of the radiator fan820. The present invention is not limited to the structure.

Specifically, in place of the radiator fan820, another fan for cooling a heating element except for the in-vehicle power device860can be used. For example, in place of the radiator fan820, an air-conditioning fan can be used. In this case, the downstream outlet872of the suction duct870can be located close to the air-conditioning fan in an air-conditioning duct in which the air-conditioning fan is disposed. Moreover, in place of the radiator fan820, a cooling fan of an alternator rotor that allows cooling air to be delivered into a frame in which the alternator rotor is rotatably supported can be used. In this case, the downstream outlet872of the suction duct870can be located close to the cooling fan in a cooling-air passage through which cooling air to be sucked or blown out by the cooling fan flows. Because those skilled in the art can easily understand the change of the radiator fan820to another fan for cooling a heating element, the descriptions of which are therefore omitted.

FIG. 21schematically illustrates an example of the structure of a downstream outlet872A of a suction duct870A of an air-cooled power system81C according to a fourth modification of the fourth embodiment. Note that other parts of the air-cooling power system810C of the fourth modification are substantially identical to those of the air-cooling power system810, and therefore, descriptions of which are simplified or omitted.

As illustrated inFIG. 21, the downstream outlet872A has an ejector configuration.

Specifically, a downstream end of the duct portion873of the suction duct870A is formed with an ejector874as the downstream outlet872A thereof. The ejector874is provided with an outer tubular wall741, a nozzle portion742, and a diffuser portion743.

The outer tubular wall741is located in the upstream cooling-air passage880in the longitudinal direction of the vehicle and opposing open ends7410and7411. The open end7410of the outer tubular wall741is directed toward the front end of the vehicle, and the open end7411thereof is directed toward the rear end of the vehicle.

The nozzle portion742has a substantially tubular cone shape and disposed in the outer tubular wall741.

Specifically, the nozzle portion742has a first open end airtightly communicated with the open end7410of the outer tubular wall741, and has a side wall tapered toward the open end7411. The nozzle portion742also is provided at its tapered tip end with a second open end opposing the first open end.

The diffuser portion743has a substantially venturi tubular shape and disposed in the outer tubular wall741.

Specifically, the diffuser portion743has opposing wider openings and a narrow opening between the wider openings. One of the wider opening is airtightly communicated with the open end7411, and the other wider opening744is located to surround the second open end of the nozzle portion742. This allows the second open end of the nozzle portion742to face the narrow opening of the diffuser portion743.

The downstream end of the duct portion873of the suction duct870A is communicated with one front-side end of the outer tubular wall741such that the downstream end of the duct portion873faces the tapered side wall of the nozzle portion742.

In the structure of the downstream outlet872A of the suction duct870A, when the radiator fan820is driven or wind is caused by the vehicle running, airflow enters via the open end7410of the outer tubular wall741into the nozzle portion742. At that time, because the nozzle portion742has a tapered structure toward the open end7411of the outer tube wall741, the airflow flows through the nozzle portion742while increasing in velocity and dropping in pressure.

In addition, because the diffuser portion743has a substantially venturi tubular shape, and the narrow opening faces the second open end of the nozzle portion742, when the low-pressure and high-velocity airflow at the downstream of the nozzle portion742passes through the narrow opening of the diffuser portion743, the low-pressure and high-velocity airflow further increases in velocity and drops in pressure.

Accordingly, air inside the suction duct870A is strongly sucked into the downstream outlet872A (ejector874), so that cooling air is strongly sucked into the in-vehicle power device860via the inlet port860a.

The low-pressure and high-velocity airflow output from the nozzle portion742and the cooling air sucked from the suction duct870A are mixed to each other by the diffuser portion743. After passing through the narrow opening of the diffuser portion743, the mixed airflow flows via the remaining diffuser portion743while kinetic energy of the mixed airflow is collected by the remaining diffuser portion743as pressure energy. For this reason, it is possible to reduce the pressure loss (fluid loss) in the upstream cooling-air passage880, thereby reducing the power to be supplied to the radiator fan820. The ejector874is preferably formed using resin molding, but can be formed using sheet metal processing.

FIGS. 22 to 24schematically illustrate a modification of the ejector874.

Specifically, a tubular wall1013is attached to the downstream end of a duct portion873B of a suction duct870B as a downstream outlet872B thereof. The tubular wall1013is so located at the upstream cooling-air passage880as to extend in the top and bottom direction of the vehicle. The tubular wall1013has a substantially C shape in its lateral cross section orthogonal to the top and bottom direction and has opposing open ends in the to and bottom direction.]

The tubular wall1013is formed at its rear end with a slit1131. As illustrated inFIG. 24, the downstream end of a duct portion873B is communicably joined to the center of a left side portion of the tubular wall1013.

Specifically, as illustrated inFIG. 22, in order to reduce the fluid loss of airflow in the upstream cooling-air passage880, the C-shaped tubular wall1013has a half-cycle wall1013aextending in the top and bottom direction and its outer surface is directed to the front side of the vehicle. The C-shaped tubular wall1013also has a taper wall1013bextending from both ends of the half-cycle wall1013ain the longitudinal direction so as to be tapered toward the rear side of the vehicle. The slit1131is formed at the tapered tip end of the taper wall1013b.

In the structure of the downstream outlet872B of the suction duct870B, when the radiator fan820is driven or wind is caused by the vehicle running, airflow enters via the open ends of the tubular wall1013thereinto. At that time, because the taper wall1013bis tapered toward the rear side of the vehicle, the airflow flows through the taper wall1013band the slit1131while increasing in velocity and dropping in pressure.

Accordingly, the negative pressure generated at the taper wall1013ballows air inside the suction duct870B to be strongly sucked into the downstream outlet872B, so that cooling air is strongly sucked into the in-vehicle power device860via the inlet port860a.

As described above, in the modification of the ejector874, use of the tubular wall1013with the simplified structure allows the ejector effect to be obtained while preventing the pressure loss (fluid loss) in the upstream cooling-air passage880from increasing.

In the first to fourth embodiments and their modifications, multiple power supply systems include a first battery and a second battery, but can be designed to include three or more batteries.

In the first to fourth embodiments and their modifications, multiple power supply systems are installed beforehand in engine vehicles, respectively, but they can be installed in hybrid vehicles. In these cases, the same effects as the embodiments can be obtained.

In the first to forth embodiments and their modifications, multiple power supply systems are installed beforehand in engine vehicles, respectively, but they can be installed in hybrid vehicles. In these cases, the same effects as the embodiments can be obtained.

While there has been described what is at present considered to be these embodiments and modifications of the present invention, it will be understood that various modifications which are not described yet may be made therein, and it is intended to cover in the appended claims all such modifications as fall within the true spirit and scope of the invention.