Battery device

A battery device includes a battery pack, a circuit substrate which acquires battery information on the battery pack or controls charge and discharge of the battery pack, a switch including a first power element or a second power element, and a heat radiator. The switch is a device controlling input and output of electric power to and from the battery pack, and an exterior part of the switch is arranged away from the circuit substrate. The heat radiator is a member made of a material having thermal conductivity, and is in direct contact with or indirect contact via a heat conductor with the exterior part of the switch so that heat of the switch can be transferred.

TECHNICAL FIELD

The present disclosure relates to a battery device.

BACKGROUND

A battery unit includes a power element for controlling input and output of electric power to and from a battery pack. The power element is mounted on a part of a control substrate at a position not overlapping with the battery pack.

SUMMARY

According to at least one embodiment of the present disclosure, a battery device includes a battery, a circuit substrate electrically connected to the battery, a switch configured to control input and output of electric power to and from the battery, and having an exterior part forming an outer surface of the switch and being away from the circuit substrate, and a heat radiator made of a material having thermal conductivity and being in contact directly or indirectly through a heat conductor with the exterior part of the switch so that heat of the switch transfers to the heat radiator.

DETAILED DESCRIPTION

Hereinafter, embodiments for implementing the present disclosure will be described referring to drawings. In each embodiment, portions corresponding to the elements described in the preceding embodiments are denoted by the same reference numerals, and redundant explanation may be omitted. In each of the embodiments, when only a part of the configuration is described, the other parts of the configuration can be applied to the other embodiments described above. The parts may be combined even if it is not explicitly described that the parts can be combined. The embodiments may be partially combined even if it is not explicitly described that the embodiments can be combined, provided there is no harm in the combination.

First Embodiment

A battery device10according to a first embodiment will be described with reference toFIGS.1to8. The battery device10can be applied to various kinds of electric devices on which a secondary battery is mounted. Such various electric devices are, for example, a device having a storage battery, a computer, a vehicle, and the like. In the first embodiment, as an example thereof, a case will be described, in which the battery device10is used for a vehicle such as a hybrid vehicle using a combination of an internal combustion engine and a battery-driven motor as a traveling drive source, or an electric vehicle traveling with a battery-driven motor.

Next, a configuration of the battery device10will be described referring toFIG.1. The battery device10includes a battery pack13having a configuration where a plurality of unit cells are stacked, a circuit substrate2that performs charge-discharge control of the battery pack13, a restraining plate12that restrains the battery pack13from above, and a case for accommodating the battery pack13. The battery device10is installed, for example, under a seat of an automobile, a space between a rear seat and a trunk compartment, or a space between a driver's seat and a passenger seat. The case has a rectangular parallelepiped shape, and includes a base case15fixed via a bracket70to a place where the battery device10is mounted, and a cover11attached to the base case15so as to cover the base case15from above. The base case15and the cover11are formed of metal, for example, aluminum, copper, alloys thereof, or formed of a resin material. When the base case15is formed of a resin material, it is preferable to use a resin material having thermal conductivity, or to mix a material having thermal conductivity with the resin material.

The battery pack13and the circuit substrate2are disposed to vertically face each other so that the battery pack13is lower than the circuit substrate2, and are individually fixed to the base case15by, for example, screws. The cover11is attached to the base case15from above, whereby the battery pack13and the circuit substrate2are accommodated in the case.

The battery device10includes a terminal block unit14for inputting and outputting power, and a connector electrically connected to, for example, a vehicle ECU. The terminal block unit14includes a terminal block unit14A for connection to a Pb storage battery, and a terminal block unit14B for connection to an ISG. The terminal block unit14A includes a first input-output terminal140connected to an external battery17inFIG.2, and a terminal block supporting the first input-output terminal140. The terminal block unit14B includes a second input-output terminal141connected to a rotary machine19inFIG.2, and a terminal block supporting the second input-output terminal141. Each terminal block is formed of an insulating resin material. The terminal block unit14A and the terminal block unit14B are individually fixed to the base case15at positions side by side.

The external battery17and an electric load18are connected to a first input-output terminal140of the terminal block unit14A through a harness. The rotary machine19is connected to a second input-output terminal141of the terminal block unit14B through a harness. The connector is connected to the vehicle ECU capable of communicating with the controller100, and is also configured to be connectable to various electric loads which are to be supplied with electric power from the battery device10. The terminal block unit14and the connector are provided on an outer peripheral portion of the case and are provided in a state of being exposed to an outside of the battery device10.

The controller100is a device that manages at least an amount of electricity stored in the battery pack, and may be a battery management unit. Further, the battery management unit may be a device that monitors current, voltage and temperature relating to the battery pack and manages, for example, abnormality of the unit cell and abnormality of electric leakage. The battery management unit is configured to be capable of communicating with various electronic control devices mounted in the vehicle. A signal related to a current value detected by a current sensor may be input to the battery management unit, or the battery management unit may be a control device that controls operations of a main relay or a pre-charge relay. The battery management unit may function as a device for controlling an operation of a motor of an air blower that drives cooling fluid in order to cool a heating element such as a unit cell. The battery management unit is configured to be capable of communicating with various electronic control devices (e.g. vehicle ECU) mounted in the vehicle.

FIG.3shows a state in which the cover11has been removed from the battery device10. The base case15includes a base15a, a fixing boss15berecting on the base15a, and a lateral wall15cerecting on the base15a. The base15ahas a rectangular shape, and the lateral wall15cis formed at a peripheral edge of the base15a. The base15ais a battery placing portion on which the battery pack13is placed. The circuit substrate2and the restraining plate12are fixed by screws or the like to the upper end portions of the lateral wall15cand the boss15b.

The base case15is integrally formed with a heat radiator6for dissipating heat generated in a first power element3and a second power element4, which are power-control semiconductor elements, to the outside. The heat radiator6forms a part of the base case15. The heat radiator6can be formed of, for example, aluminum, copper, or an alloy thereof. The first power element3and the second power element4are semiconductor switching elements, and are an example of a switch that controls input and output of power to and from the battery. The heat radiator6is provided at a position adjacent to the battery pack13, and a flat portion on an upper surface of the heat radiator6faces exterior portions of the first power element3and the second power element4across a heat conductor5. The circuit substrate2is electrically and individually connected to the battery pack13and the switch.

The exterior part corresponds to an exterior case for protecting the heart of the device, and is made of various materials capable of releasing heat generated inside to outside. The exterior part is in the shape of a flattened rectangular parallelepiped and made of, for example, resin. The heat conductor5is a member having thermal conductivity and electrical insulating properties, and for example, a member made of a silicon based material can be used. The heat conductor5is preferably deformable by an external force so as to be in close contact with the heat radiator6or the exterior part forming the outer surface of the switch, and may be made of an elastically deformable sheet, gel or grease, for example. The heat conductor5transfers heat and electrically insulates between each power element and the heat radiator6.

The heat radiator6is connected to a vehicle member7which is a part of a vehicle through the bracket70such that heat is allowed to be transferred from the heat radiator6to the vehicle member7. The vehicle member7is, for example, a frame member through which a predetermined device is fixed to the vehicle, a member coupled to a chassis, or a member supporting an interior material forming an interior of the vehicle compartment. The bracket70is made of a material having thermal conductivity, and is an attachment connecting the base15aand the vehicle member7. The heat radiator6has a rectangular box body whose inside is a hollow. As indicated by arrows inFIG.3, the heat generated by each power element moves from its exterior part through the heat conductor5to a contact part with the heat radiator6, and moves downward from a flat part of the heat radiator6to a lateral wall of the box body. Further, the heat is transferred from a lower end of the lateral wall to the base15aand is released to the vehicle member7via the bracket70. The heat radiator6may be directly connected to the vehicle member7without through the bracket70.

As shown inFIG.2, a circuit configuration related to the battery device10includes the external battery17, the battery pack13, the rotary machine19that is a motor generator, the electric load18, the first power element3, the second power element4and the controller100. The battery pack13is an internal battery installed inside a case that houses the battery device10, and includes, for example, a lithium ion secondary battery. The battery pack13is preferably a secondary battery having low resistance and excellent regenerative performance. The external battery17is a secondary battery installed outside the case that houses the battery device10, and includes, for example, a lead storage battery. The external battery17is preferably a secondary battery having a large capacity.

The components constituting the controller100are mounted on the circuit substrate2. The controller100performs switching between ON (closing) and OFF (opening) of each of the power elements, thereby controlling charging and discharging of each of the external battery17and the battery pack13. As shown inFIG.4, in the battery device10, the switches such as the first power element3and the second power element4are connected to the circuit substrate2in a state where signal communication is possible through a signal line31in which current for power supply does not flow. Furthermore, in the switch, a power line32through which a large current for power supply flows is not connected to the circuit substrate2. Therefore, in the switch, a large current flowing through a switch body and the power line32is not transmitted to the circuit substrate2.

In the battery device10, the first input-output terminal140and a second input-output terminal141are provided as external terminals. The external battery17and the electric load18are connected in parallel to the first input-output terminal140. The first power element3and the second input-output terminal141are connected in series to a side of the first input-output terminal140opposite from the external battery17. Further, the external battery17is connected to the electric load18so as to be capable of supplying electric power. The electric load18is a general electrical load other than an electric load requiring constant voltage. The electric load18is, for example, a headlight, a wiper for a front windshield or the like, a blower fan of an air conditioner, or a heater for defogging of a rear windshield.

The second power element4and the battery pack13are connected in series to a connection part between the first power element3and the second input-output terminal141. The rotary machine19is connected to a side of the second input-output terminal141opposite from the first power element3. The first power element3and the second power element4are connected in parallel to the rotary machine19. The first power element3as a first switch functions as a switch that switches between a power supply state and a non-power supply state. In the power supply state, power supply can be performed between the rotary machine19and each of the external battery17and the electric load18. In the non-power supply state, such power supply cannot be performed. The second power element4as a second switch functions as a switch that switches between a power supply state and a non-power supply state. In the power supply state, power supply can be performed between the rotary machine19and the battery pack13. In the non-power supply state, such power supply cannot be performed.

The rotary machine19has a power generating function of generating power by rotation of a crankshaft of an engine, i.e. regenerative electric power, and a power output function of imparting rotational force to the crankshaft, thereby constituting an ISG (Integrated Starter Generator). The external battery17and the battery pack13are electrically connected in parallel to the rotary machine19. When the first power element3is turned on, the external battery17becomes ready for being supplied with electric power from the rotary machine19, and the regenerative electric power can be charged. When the second power element4is turned on, the battery pack13becomes ready for being supplied with electric power from the rotary machine19, and the regenerative electric power can be charged. Therefore, each of the first power element3and the second power element4forms a part of a large current path in which a relatively large current flows between the rotary machine19and each battery.

Next, with reference toFIG.4andFIG.5, a relation of arrangement of the circuit substrate2, each power element, the heat conductor5and the heat radiator6will be described. Since the first power element3and the second power element4have similar configurations with respect to the relation of arrangement with the circuit substrate2, the first power element3will be described as a representative in the following descriptions. Therefore, in the following descriptions, it is possible to explain the relation of arrangement of the second power element4and the circuit substrate2and the like by replacing the first power element3with the second power element4.

As shown inFIG.4andFIG.5, the first power element3is disposed below and away from the circuit substrate2, and has a thickness direction that is orthogonal to the main surface of the circuit substrate2. Thus, the first power element3is transversely placed and is in contact indirectly with the heat radiator6via the heat conductor5. Therefore, the first power element3and the heat radiator6are disposed at positions below the circuit substrate2. In the first power element3, a direction in which the signal line31and the power line32protrude from the exterior part30is parallel to a direction along the main surface of the circuit substrate2. A direction along an element width that is a length between ends from which the signal line31and the power line32protrude is parallel to the direction along the main surface of the circuit substrate2. The first power element3has an outer shape in which the width of the exterior part30is longer than its thickness.

The signal line31extends laterally from the exterior part30and then extends so as to be bent in a direction orthogonal to the main surface of the circuit substrate2. The signal line31is connected to the circuit substrate2or connected to electronic components mounted on the circuit substrate2. The power line32of the first power element3is not connected to the circuit substrate2, and is connected to the first input-output terminal140and the second input-output terminal141via a bus bar33. The power line32is a conductive terminal joined to the bus bar33by welding, for example. The bus bar33is supported by a bus-bar support16which is accommodated in the base case15together with the battery pack13and others. The bus bar33is a conductive plate member coupled to the first input-output terminal140and the second input-output terminal141. The bus-bar support16is also a bus-bar casing that houses the bus bar33in a stable state. The bus-bar support16is formed of a material having electrical insulation properties to insulate the bus bar33from surrounding members.

The heat radiator6has a thermal connection portion with the first power element3on a surface extending in the lateral direction. In addition, the exterior part30may be configured to be in direct contact with the heat radiator6. Means for fixing the first power element3to the heat conductor5or the heat radiator6may include fastening with an insulating adhesive, for example, a silicon-based adhesive, a bolt or a screw. The heat radiator6is disposed on the base15aof the base case15accommodating the battery pack13in such a configuration that heat can be transferred from the heat radiator6to the base15a. According to the above configuration, the heat transferred from the exterior part30of the power element3to the heat radiator6through the heat conductor5transfers to the base15a, and further transfers to the vehicle member7via the bracket70, thereby the heat being released.

As shown inFIG.5, an end portion20, which is a part of an outer peripheral edge of the circuit substrate2, is located at a position overlapping with the first power element3that exists at a position lower than the circuit substrate2. In other words, a first end portion30a, which is a part of an outer peripheral edge of the first power element3facing the substrate, is provided at a position directly below the circuit substrate2. A second end portion30bopposite to the first end portion30ais provided at a position below and outside the circuit substrate2. Therefore, when the first power element3and the circuit substrate2are viewed from above, the first power element3positioned below the circuit substrate2has an overlapping portion30cthat overlaps the circuit substrate2, and a remaining portion30dthat does not overlap the circuit substrate2. Further, it is preferable, from the viewpoints of heat dissipation and ease of connection with the bus bar33, that the first power element3and the circuit substrate2have a positional relationship that the volume of the remaining portion30dis equal to or larger than the volume of the overlapping portion30c.

The battery pack13includes a plurality of unit cells connected in series to each other, and these unit cells are accommodated in a battery case in a predetermined arrangement. In this embodiment, as shown inFIG.1, a first battery stack13aincluding two unit cells vertically stacked each other and a second battery stack13bincluding three unit cells vertically stacked each other are arranged side by side in two rows. Each of the five unit cells is a thin rectangular parallelepiped lithium ion secondary battery, and is installed horizontally with its thickness direction becoming parallel to the vertical direction. Since all of the unit cells constituting the battery stacks are connected in series, the battery stacks are electrically connected. All the battery stacks are electrically connected and are integrated to each other, thereby functioning as the battery pack13of the battery device10.

Next, in the battery device10, the positional relationship between the battery pack13and the switches will be described with reference toFIGS.6to8. The battery pack13of an example shown inFIG.6is composed of one battery stack. In this case, a part or whole of the element group including the first power element3and the second power element4is in a predetermined area AR1which is, in top view, adjacent to the battery stack inside the battery device10and has a length same as the width of the battery stack. It is preferable that at least a part of elements that are the first power element3and the second power element4is in the area AR1which is adjacent to electrode terminals130of the battery stack in the protruding direction of the electrode terminals130. According to the battery pack13having such configuration, it is possible to shorten the distance between the battery, the power element, and the input-output terminal. Although the battery pack13shown inFIG.6is constituted by the plurality of unit cells stacked in the vertical direction, it may be constituted by a plurality of unit cells stacked in the transverse direction.

The battery pack13of an example shown inFIG.7is composed of two battery stacks having the same number of stacked unit cells. In this case, a part or whole of the element group including the first power element3and the second power element4is in a predetermined area AR2which is, in top view, adjacent to the two battery stacks inside the battery device10and has a length same as a length of the two battery stack in its alignment direction. It is preferable that at least a part of elements that are the first power element3and the second power element4is in the area AR2which is adjacent to electrode terminals130of the battery stack in the protruding direction of the electrode terminals130. Although the battery pack13shown inFIG.7is constituted by the plurality of unit cells stacked in the vertical direction, it may be constituted by a plurality of unit cells stacked in the transverse direction.

The battery pack13of an example shown inFIG.8is composed of two battery stacks13a,13bhaving different number of stacked unit cells. In this case, a part or whole of the element group including the first power element3and the second power element4is in a predetermined area AR3which is, in top view, adjacent to the first battery stack13ahaving smaller number of stacked unit cells inside the battery device10and has a length same as the width of the first battery stack13a. According to the battery pack13having such configuration, since the power element is installed in a place close to the first battery stack13awhich has a smaller number of stacked unit cells and a smaller heat generation among the multiple battery stacks, thermal heterogeneity in the battery device10can be reduced.

It is preferable that at least a part of elements that are the first power element3and the second power element4is in the area AR3which is adjacent to electrode terminals130of the battery stack13ain the protruding direction of the electrode terminals130. Although the battery pack13shown inFIG.8is constituted by the plurality of unit cells stacked in the vertical direction, it may be constituted by a plurality of unit cells stacked in the transverse direction. In addition, each of the battery packs13shown inFIGS.6to8may be configured such that the protruding direction of the electrode terminals130is not in the lateral direction but in the upward direction or the downward direction.

Next, effects obtained by the battery device10of the first embodiment will be described. The battery device10includes the battery pack13, the circuit substrate2which acquires battery information on the battery pack13or controls charge and discharge of the battery pack13, the switch including the first power element3and the second power element4, and the heat radiator6. The switch is a device controlling input and output of electric power to and from the battery pack13, and the exterior part30of the switch is arranged in a state of being separated from the circuit substrate2. The heat radiator6is a member made of a material having thermal conductivity, and is in direct contact with or indirect contact via the heat conductor5with the exterior part30of the switch so that heat of the switch can be transferred.

According to this battery device10, the switch is in a state where the exterior part30is away from the circuit substrate2, and the exterior part30is in contact directly or indirectly through the heat conductor5with the heat radiator6. As a result, the heat of the switch can be quickly transferred to the heat radiator6rather than to the circuit substrate2. Therefore, it is possible to realize the battery device10, in which it is unnecessary to take measures to suppress heat generation of the switch for preventing the circuit substrate2from being greatly increased in temperature due to heat generation of the switch. In addition, it is possible to avoid situations where the heat resistant temperature of the circuit substrate2becomes a bottleneck and the performance of the switch cannot be fully delivered. Therefore, a high output battery device10can be realized. Therefore, it is possible to provide the battery device10capable of delivering the performance of the switch without restriction of the heat resistant temperature of the circuit substrate2.

The switch includes the signal line31transmitting an electric signal, and a power line32transmitting electric power. The power line32is not connected to the circuit substrate2, but is connected to the input-output terminals140,141of the battery via the bus bar33. The signal line31is a lead terminal protruding outward from the inside of the switch and is connected to the circuit substrate2. The signal line31is connected to the circuit substrate2by extending the signal line31through the hole of the substrate and soldering it to one side or both sides of the substrate. According to this configuration, since no large current flows through the signal line31, large heat transfer from the signal line31to the circuit substrate2does not occur. Since the power line32is not connected to the circuit substrate2, heat generated in the power line32is prevented from transferring to the circuit substrate2. Therefore, the heat generated in the power line32can be transferred to the heat radiator6through the switch and release the heat, and thereby released.

The heat radiator6is connected to the vehicle member7which is a part of a vehicle directly or indirectly through the bracket70having thermal conductivity such that heat is allowed to be transferred from the heat radiator6to the vehicle member7. According to this configuration, since heat of the switch can be transferred to the vehicle member7having a large heat capacity through the heat radiator6, the heat of the switch can be promptly discharged to the outside of the battery device10. Further, heat can be dissipated in a simple manner by using the vehicle member7without using a dedicated cooler.

The heat radiator6is disposed on the base15aof the base case15accommodating the battery in such a configuration that heat can be transferred from the heat radiator6to the base15ahaving thermal conductivity. According to this configuration, since heat of the switch can be transferred to the outside of the battery device10through a whole of the bottom of the case housing the battery, the heat of the switch can be promptly discharged to the outside.

The switch and the heat radiator6are positioned away from and below the circuit substrate2. According to this configuration, the heat of the switch can be quickly transferred downward from the circuit substrate2. Thus, heat radiation toward the upper circuit substrate2can be reduced, and thermal influence on electronic components mounted on the circuit substrate2can be reduced.

The switch and the heat radiator may be positioned away from and above the circuit substrate2. According to this configuration, the heat of the switch can be quickly transferred upward above the circuit substrate2by utilizing heat upward rise. Accordingly, heat radiation downward to the circuit board2can be reduced, and thermal influence on the electronic components mounted on the circuit substrate2can be reduced.

When the switch and the circuit substrate2are viewed from above, the switch has the overlapping portion30cthat overlaps the circuit substrate2, and the remaining portion30dthat does not overlap the circuit substrate2. The switch is positioned such that the volume of the remaining portion30dis larger than or equal to the volume of the overlapping portion30c. According to this configuration, it is possible to provide a configuration in which heat radiation from the surface of the exterior part30of the switch to the circuit substrate2is reduced.

The battery pack13is arranged in such a manner that the electrode terminals130are exposed in the lateral direction. The switch is positioned closer to the electrode terminals130with respect to the battery pack13. According to such configuration, it is possible to provide the battery device10capable of shortening a length of electric path between the battery, the switch, and the input-output terminal.

The switch is positioned closer to the battery stack13ahaving a smaller number of stacked unit cells among the multiple battery stacks. According to this configuration, the switch can be placed close to the battery stack13ahaving a small number of stacks and a small heat generation amount. Thus, it is possible to provide the battery device10can reduce heterogeneity of heat generation areas in the entire battery device10.

The switch includes the first switch that controls input and output of electric power to and from the external battery17provided outside the battery device10, and the second switch that controls input and output of electric power to and from the battery included in the battery device10. According to this configuration, the heat of the first switch that controls the input and output of electric power to and from the external battery17and the heat of the second switch that controls input and output of electric power to and from the battery included in the battery device10can be quickly transferred to the heat radiator6to be released. Therefore, it is possible to provide the battery device10capable of delivering the performance of both the first switch and the second switch without restriction of the heat resistant temperature of the circuit substrate2.

Second Embodiment

In a second embodiment, a battery device including a heat radiator106which is another embodiment of the first embodiment will be described with reference toFIG.9. InFIG.9, components denoted by the same reference numerals as those in the drawings of the first embodiment are the same components and exert similar operational effects. The heat radiator106exerts the same effect as that of the heat radiator6of the first embodiment. Hereinafter, contents different from the first embodiment will be described.

As shown inFIG.9, the heat radiator106is indirectly in contact with the exterior part30of the first power element3through the heat conductor5so that heat of the first power element3can be transferred to the heat radiator106. In addition, the heat radiator106may be directly in contact with the exterior part30. The heat radiator106has a heat release path for releasing the heat transferred from the exterior part30of the first power element3through the heat conductor5, for example, a path through which the heat is released from a plurality of fin portions to ambient air. Similar to the heat radiator6, the heat radiator106is made of a material having thermal conductivity, for example, various metals such as aluminum, copper, and alloys thereof.

Third Embodiment

In a third embodiment, a configuration related to a thermal connection between a first power element3and a heat radiator206, which is another embodiment of the first embodiment, will be described with reference toFIG.10. InFIG.10, components denoted by the same reference numerals as those in the drawings of the first embodiment are the same components and exert similar operational effects. The heat radiator206exerts the same effect as that of the heat radiator6of the first embodiment. Hereinafter, contents different from the first embodiment will be described.

As shown inFIG.10, the first power element3is disposed such that its thickness direction is along the main surface of the circuit substrate2, and the first power element3is in contact indirectly with the heat radiator206via the heat conductor5. The first power element3is in contact with the heat radiator206such that heat can be transferred therebetween, and first power element3is vertically arranged such that an extending direction of the signal line31from the exterior part30is orthogonal to the main surface of the circuit substrate2. Thus, the heat radiator206has a thermal connection portion with the first power element3on a surface extending in the vertical direction. In addition, the exterior part30may be configured to be in direct contact with the heat radiator206. The heat radiator206is, similar to the heat radiator6, disposed on the base15aof the base case15accommodating the battery pack13in such a configuration that heat can be transferred from the heat radiator206to the base15a.

According to the above configuration, the heat transferred from the exterior part30of the first power element3to the heat radiator206through the heat conductor5transfers to the base15a, and further transfers to the vehicle member7through the bracket70, thereby the heat being released. Further, the heat radiator206in the third embodiment can be replaced with the heat radiator106of the second embodiment. This replacement provides a heat release path for radiating the heat emitted from the exterior part30of the first power element3to the ambient air from the plurality of fin portions.

According to the third embodiment, the first power element3, the heat conductor5, and the heat radiator206can be disposed directly below or directly above the circuit substrate2. Therefore, the size of the battery device10in the lateral direction can be reduced. Further, according to the third embodiment, the power line32extending from an end portion of the exterior part30opposite from the end portion from which the signal line31extends can be positioned away from the circuit substrate2. Thus, it is possible to reduce influence of noise on the circuit substrate2.

Fourth Embodiment

In a fourth embodiment, a configuration related to a thermal connection between a first power element3and a heat radiator206, which is another embodiment of the third embodiment, will be described with reference toFIG.11. InFIG.11, components denoted by the same reference numerals as those in the drawings of the above embodiments are the same components and exert similar operational effects. The heat radiator306exerts the same effect as that of the heat radiator6or the heat radiator206. Hereinafter, contents different from the third embodiment will be described.

As shown inFIG.11, the first power element3is disposed such that its thickness direction is oblique to the main surface of the circuit substrate2, and the first power element3is in contact indirectly with the heat radiator306via the heat conductor5. The first power element3is in contact with the heat radiator306such that heat can be transferred therebetween, and the first power element3is oblique to the main surface of the circuit board2. Thus, the heat radiator306has a thermal connection portion with the first power element3on a surface extending in a direction oblique to the vertical direction. In addition, the exterior part30may be configured to be in direct contact with the heat radiator306. The heat radiator306is, similar to the heat radiator206, disposed on the base15aof the base case15accommodating the battery pack13in such a configuration that heat can be transferred from the heat radiator306to the base15a.

According to the fourth embodiment, the first power element3, the heat conductor5, and the heat radiator306can be disposed directly below or directly above the circuit substrate2. Therefore, the size of the battery device10in the lateral direction can be reduced. Further, similar to the third embodiment, since the power line32can be positioned away from the circuit substrate2, the influence of noise on the circuit substrate2can be reduced.

Fifth Embodiment

In a fifth embodiment, a battery device110which is another embodiment of the first embodiment will be described with reference toFIG.12. InFIG.12, components denoted by the same reference numerals as those in the drawings of the first embodiment are the same components and exert similar operational effects. The heat release path from the first power element3to the vehicle member7in the battery device110is similar to that of the battery device10of the first embodiment. The battery device110exhibits the same operational effects as those of the battery device10described in the first embodiment. Hereinafter, contents different from the first embodiment will be described.

As shown inFIG.12, the first power element3is disposed directly below the circuit substrate2. Therefore, the circuit substrate2extends directly above the first power element3. The power line32of the first power element3is not connected to the circuit substrate2, and is connected to the first input-output terminal140and the second input-output terminal141via a bus bar33. The signal line31of the first power element3is connected to the circuit substrate2.

According to the battery device110of the fifth embodiment, since the highest position of the first power element3is below the circuit board2, the heat release path from the first power element3to the base15acan be shortened. Therefore, the heat release path of the battery device110can be shortened and contribute to improvement of a heat release performance.

Sixth Embodiment

In a sixth embodiment, a battery device210which is another embodiment of the first embodiment will be described with reference toFIG.13. InFIGS.13and14, components denoted by the same reference numerals as those in the drawings of the first embodiment are the same components and exert similar operational effects. The heat release path from the first power element3to the vehicle member7in the battery device210is different from that of the battery device10of the first embodiment. Hereinafter, contents different from the first embodiment will be described.

As shown inFIG.13, the first power element3is disposed directly above the circuit substrate2. Therefore, the circuit substrate2exists directly below the first power element3. The first power element3is in contact indirectly with the heat radiator406through the heat conductor5. The heat radiator406is provided on an inner surface of the top wall of the cover11such that heat can be transferred from the heat radiator406to the cover11. The cover11is made of a material having thermal conductivity and is mounted on the base15aof the base case15such that heat can be transferred from the cover11to the base15a. The heat transferred from the exterior part30of the first power element3to the heat radiator406through the heat conductor5transfers to the top wall of the cover11, the lateral wall extending downward, the base15a, and then the vehicle member7through the bracket70, thereby the heat being released.

As shown inFIG.14, the power line32of the first power element3is not connected to the circuit substrate2, and is connected to the first input-output terminal140and the second input-output terminal141through a harness133. The signal line31is connected to the circuit substrate2. As shown by a dash line inFIG.14, the end portion20, which is a part of the outer peripheral edge of the circuit substrate, is located at a position overlapping with the first power element3that exists at a position higher than the circuit substrate2. In other words, the first end portion30a, which is a part of the outer peripheral edge of the first power element3facing the substrate, is provided at a position directly above the circuit substrate2. The second end portion30bopposite to the first end portion30ais provided at a position above and outside the circuit substrate2. Therefore, when the first power element3and the circuit substrate2are viewed from above, the first power element3includes the overlapping portion30cthat overlaps the circuit substrate2, and the remaining portion30dthat does not overlap the circuit substrate2. Further, it is preferable that the first power element3and the circuit substrate2have a positional relationship that the volume of the remaining portion30dis equal to or larger than the volume of the overlapping portion30c.

According to the sixth embodiment, the distance between the power line32and the circuit substrate2to which the signal line31is connected can be secured. Thus, the influence of noise on the circuit substrate2can be reduced, and the existence of the overlapping portion30ccontributes to miniaturization of the battery device210. In addition, since the power line32protrudes outward of the circuit substrate2, it is possible to provide a structure that facilitates coupling between the power line32and the harness133. Since the heat of the first power element3is more easily transmitted to the upper side than the lower side, a capability of releasing the heat of the first power element3can be enhanced.

Seventh Embodiment

In the seventh embodiment, the battery device210of the sixth embodiment is placed vertically with respect to the vehicle member7and will be described with reference toFIG.15. InFIG.15, components denoted by the same reference numerals as those in the drawings of the above embodiments are the same components and exert similar operational effects. The heat release path from the first power element3to the vehicle member7in the battery device210placed as in the seventh embodiment is similar to that of the sixth embodiment. The battery device210of the seventh embodiment exhibits the same operational effects as the operational effects described in the sixth embodiment.

Eighth Embodiment

In an eighth embodiment, a battery device310which is another embodiment of the first embodiment will be described with reference toFIG.16. InFIG.16, components denoted by the same reference numerals as those in the drawings of the first embodiment are the same components and exert similar operational effects. The heat release path from the first power element3or the second power element4to the vehicle member7in the battery device310is similar to that of the battery device10of the first embodiment. The battery device310exhibits the same operational effects as those of the battery device of the first embodiment or the fifth embodiment. Points different from the first embodiment and the fifth embodiment will be described below.

As shown inFIG.16, the heat radiator6of the battery device310forms a part of a base case115. The heat radiator6forms a standing wall standing from the base15awhich is the bottom of the base case115. The heat radiator6is made of the same material as the base case115, for example, aluminum, copper, or an alloy thereof. The first power element3and the second power element4are disposed such that their exterior parts are in contact directly or indirectly through the heat conductor5with the standing wall erecting from the base15a. In addition, the first power element3, the second power element4, and the heat radiator are positioned below and away from the circuit substrate2as shown inFIG.16, but may be, alternatively, positioned above and away from the circuit substrate2.

According to the battery device310of the eighth embodiment, the heat radiator6is a part of the base case115and is the standing wall formed so as to erect from the base15a. According to this configuration, since the heat radiator6is a part of the base case115, resistance of heat transfer from the heat radiator6to the base case115can be reduced, and the capability of releasing heat of the switch can be improved. Since the heat radiator6is a part of the base case115and is the standing wall standing upright from the base15a, the standing wall can prevent the switch from being wet or submerged. In addition, the standing wall for protecting the battery pack13from being wet or immersed can be utilized as the heat radiator6, and thereby the battery device310can be downsized and the number of components can be reduced.

The exterior part of the switch is in contact directly or indirectly through the heat conductor5with the upper surface of the standing wall which is the heat radiator6. According to this configuration, the switch can be placed at a high position by utilizing the standing wall. Thus, it is possible to provide the battery device310in which the switch is hardly brought into a state of being wet or submerged.

Ninth Embodiment

In a ninth embodiment, a battery device410which is another embodiment of the first embodiment will be described with reference toFIG.17. InFIG.17, components denoted by the same reference numerals as those in the drawings of the first embodiment are the same components and exert similar operational effects. The heat release path from the first power element3or the second power element4to the vehicle member7in the battery device410is similar to that of the battery device10of the first embodiment. The battery device410exhibits the same operational effects as those of the battery device of the first embodiment or the eighth embodiment. Points different from the first embodiment and the eighth embodiment will be described below.

As shown inFIG.10, the first power element3and the second power element4are disposed such that their thickness direction are along the main surface of the circuit substrate2, and the first power element3and the second power element4are in contact indirectly through the heat conductor5with the heat radiator6forming the standing wall erecting from the base15a. The first power element3and the second power element4are in contact with the heat radiator6such that heat can be transferred therebetween, and first power element3and the second power element4are vertically arranged such that an extending direction of the signal line from the exterior part is orthogonal to the main surface of the circuit substrate2. The first power element3and the second power element4are disposed on a lateral surface60of the standing wall erecting from the base15a. Thus, the standing wall as the heat radiator6has the lateral surface60spreading in the vertical direction in a thermal connection portion with the first power element3and facing inward the battery pack13.

In addition, the exterior part30of the first power element3and the exterior part of the second power element4may be in direct contact with the standing wall. Further, the first power element3, the second power element4, and the heat radiator are positioned below and away from the circuit substrate2as shown inFIG.17, but may be, alternatively, positioned above and away from the circuit substrate2.

According to the above configuration, the heat transferred from the exterior part of each power element through the heat conductor5to the standing wall of the heat radiator6is transferred in the lateral direction to an outer lateral surface to be released to ambient air and also transferred to the base15aand then to the vehicle member7through the bracket70.

According to the ninth embodiment, the exterior part of the switch is in contact directly or indirectly through the heat conductor5with the lateral surface60of the standing wall which is the heat radiator6. According to this configuration, heat generated from the switch can be released to the outside atmosphere through the standing wall, and also can be released to the vehicle member7through the base15a. These two heat release paths enhance the heat radiation performance, and each heat release path can be short.

According to the battery device410of the ninth embodiment, the thickness direction of the switch set parallel to the width direction or the lateral direction of the battery device410. Thus, the size of the battery device410in its width direction can be reduced.

The exterior part of the switch is in contact directly or indirectly through the heat conductor5with the lateral surface60that faces the battery pack13on the standing wall which is the heat radiator6. According to this configuration, the switch can be protected from external force. Further, the standing wall serves as a barrier against water from the outside or water immersion, and thus the waterproof effect of the switch can be enhanced.

The exterior part of the switch may be in contact directly or indirectly through the heat conductor5with the lateral surface that is on an outer side of the standing wall which is the heat radiator6.

The disclosure of this specification is not limited to the illustrated embodiment. The disclosure encompasses the illustrated embodiments and modifications by those skilled in the art based thereon. The present disclosure is not limited to combinations disclosed in the above-described embodiment but can be implemented in various modifications. The present disclosure can be implemented in various combinations. The disclosure may have additional parts that may be added to the embodiment. The disclosure encompasses omissions of parts and/or elements of the embodiments. The disclosure encompasses replacement or combination of parts and/or elements between one embodiment and another. The disclosed technical scope is not limited to the description of the embodiment.

The power element in the above embodiments can be replaced with a mechanical relay that does not have a semiconductor element and controls input and output of electric power to and from the battery. The mechanical relay is, for example, a switch having a coil and a contact and controlling the input and output of electric power by closing the contact and allowing current to flow therethrough. In the case of a mechanical relay, its exterior part forms a rectangular parallelepiped case made of resin, for example. As described above, the signal line31and the power line32individually protrude outside the case. As described above, an example of the switch of the present disclosure includes the power element and the mechanical relay.

In the above embodiment, the unit cells constituting the external battery17and the assembled battery13are not limited to the lead storage battery and the lithium ion secondary battery described in the first embodiment, and may be, for example, a nickel hydrogen secondary battery or an organic radical battery.

In the above embodiments, the power element and the circuit substrate2partially overlap each other when viewed from above. However, the power element and the circuit substrate2may entirely overlap each other. In addition, the power element and the circuit substrate2may not overlap at all.

In the above-described embodiment, the unit cell included in the battery device may have a configuration in which an exterior case has a thin flat plate shape and the exterior case is formed of a laminate sheet, for example. The laminate sheet is made of a highly insulating material. In this case, the unit cell has an internal space of a flat container that is hermetically sealed by sealing the end portions of the laminate sheet, for example, by heat-sealing the end portions of the laminate sheet. The internal space houses therein a battery main body including an electrode assembly, an electrolyte, a terminal connector, a part of a positive electrode terminal, and a part of a negative electrode terminal. Therefore, in the unit cell, the peripheral edge of the flat container is sealed, and thus the battery main body is hermetically housed in the flat container. The unit cell has a pair of electrode terminals drawn outward from the flat container.

In the above-described embodiments, the unit cell included in the battery device may employ, for example, a unit cell having a columnar outer shape.

In the above-described embodiments, the battery provided in the battery device can be composed of one or more unit cells. The multiple unit cells may be stacked in the vertical direction or may be stacked side by side in the horizontal direction.

A comparative example will be described. In a battery unit of the comparative example, a power element for power control is mounted on a control substrate. Therefore, there is a restriction of heat resistant temperature of the control substrate which is lower in heat resistant temperature than the power element. Due to the restriction of the heat resistance temperature, heat generation of a switch is required to be reduced, and it may be difficult to deliver a necessary switching performance.

In contrast, according to the present disclosure, the battery device is capable of improving a performance of a switch which controls input and output of power to and from a battery.

According to an embodiment of the present disclosure, the battery device includes a battery, a circuit substrate, a switch and a heat radiator. The circuit substrate is electrically connected to the battery. The switch is configured to control input and output of electric power to and from the battery, and has an exterior part forming an outer surface of the switch and being away from the circuit substrate. The heat radiator is made of a material having thermal conductivity and is in contact directly or indirectly through a heat conductor with the exterior part of the switch so that heat of the switch transfers to the heat radiator.

According to the battery device of the present disclosure, the switch is in a state where the exterior part is away from the circuit substrate, and the exterior part is in contact directly or indirectly through the heat conductor with the heat radiator. Thus, the heat of the switch quickly transfers to the heat radiator rather than to the circuit substrate. Therefore, the battery device can be obtained, in which it is unnecessary to take measures for suppressing heat generation of the switch in order to reduce a thermal influence on the circuit substrate. In addition, it is possible to avoid situations where the heat resistant temperature of the circuit substrate becomes a bottleneck and the performance of the switch cannot be fully delivered. Therefore, it is possible to provide the battery device capable of delivering the performance of the switch without restriction of the heat resistant temperature of the circuit substrate.

While the present disclosure has been described with reference to embodiments thereof, it is to be understood that the disclosure is not limited to the embodiments and constructions. To the contrary, the present disclosure is intended to cover various modification and equivalent arrangements. In addition, while the various elements are shown in various combinations and configurations, which are exemplary, other combinations and configurations, including more, less or only a single element, are also within the spirit and scope of the present disclosure.