Vehicle

A vehicle includes a power receiving portion that is mounted below a floor panel and that receives electric power in a contactless manner from a power transmitting portion provided outside the vehicle, an electromagnetic shield that prevents an electromagnetic field from passing through, a power receiving portion cover that allows the electromagnetic field to pass through and covers the power receiving portion, and an undercover that allows the electromagnetic field to pass through and covers the power receiving portion cover.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to a vehicle.

2. Description of Related Art

In recent years, hybrid vehicles and electric vehicles and the like in which the driving wheels are driven using electric power from a battery or the like are receiving a lot of attention in consideration of the environment.

In particular, in recent years, with electric vehicles provided with this kind of battery, wireless charging that enables the battery to be charged in a contactless manner without using a plug or the like is gaining attention. Recently, a variety of contactless charging methods have even been proposed.

For example, International Publication No. 2011/108403, Japanese Patent Application Publication No. 2010-268660 (JP 2010-268660 A), and Japanese Patent Application Publication No. 2011-204836 (JP 2011-204836 A) describe power transfer systems using a contactless charging method.

With these power transfer systems, a power receiving apparatus that includes a power receiving portion is mounted in a vehicle. To actually mount the power receiving portion in the vehicle, the power receiving portion is arranged below a floor panel of the vehicle. In this case, the power receiving portion must be protected from objects such as mud, rocks, and water that fly in all directions from outside the vehicle.

The patent documents above describe structures in which a power receiving apparatus that includes a power receiving portion is mounted below a floor panel of a vehicle, or near the floor panel. However, there is no mention of a specific structure for protecting the power receiving portion from objects such as mud, rocks, and water that fly in all directions from outside the vehicle.

SUMMARY OF THE INVENTION

The invention this provides a vehicle having a specific protective structure for a power receiving portion that receives electric power in a contactless manner from a power transmitting portion provided outside the vehicle, when such a power receiving portion is mounted in the vehicle.

One aspect of the invention relates to a vehicle that includes a power receiving portion that receives electric power in a contactless manner from a power transmitting portion provided outside the vehicle, an electromagnetic shield that prevents an electromagnetic field from passing through, a first cover that allows the electromagnetic field to pass through and covers the power receiving portion, and a second cover that allows the electromagnetic field to pass through and covers the first cover.

In the vehicle of one aspect of the invention, the electromagnetic shield may be provided in a position on an opposite side of the power receiving portion from the power transmitting portion side.

In the vehicle of one aspect of the invention, the power receiving portion may be mounted below a floor panel of the vehicle.

In the vehicle of one aspect of the invention, the electromagnetic shield may be open on a lower side where the power receiving portion is located, and surround the power receiving portion from above and a side in a horizontal direction, the first cover may be positioned below the power receiving portion and cover the power receiving portion, and the second cover may be positioned below the first cover and cover the first cover.

In the vehicle of one aspect of the invention, the electromagnetic shield may include a base portion positioned on the floor panel side, and a side wall portion that surrounds the base portion at an edge portion of the base portion, and extends downward from the base portion. Also, the first cover may be fixed to the electromagnetic shield so as to cover the power receiving portion, and the second cover may be fixed to the floor panel so as to cover the electromagnetic shield.

In the vehicle of one aspect of the invention, the first cover may be fixed to the base portion, in a position toward an inside, which is the power receiving portion side, of the side wall portion of the electromagnetic shield, so as to cover the power receiving portion.

In the vehicle of one aspect of the invention, the first cover may be fixed to the side wall portion of the electromagnetic shield.

In the vehicle of one aspect of the invention, the first cover may be fixed to the electromagnetic shield with a seal member disposed between the first cover and the electromagnetic shield.

In the vehicle of one aspect of the invention, the electromagnetic shield may include a base portion positioned on the floor panel side, and a side wall portion that surrounds the base portion at an edge portion of the base portion, and extends downward from the base portion. Also, the first cover portion may be fixed to the floor panel at a position on a side opposite of the side wall portion of the electromagnetic shield from the power receiving portion so that the first cover portion covers the power receiving portion, and the second cover may be fixed to the floor panel so as to cover the electromagnetic shield.

In the vehicle of one aspect of the invention, the first cover may be fixed to the floor panel with a seal member disposed between the first cover and the floor panel.

In the vehicle of one aspect of the invention, a difference between a natural frequency of the power transmitting portion and a natural frequency of the power receiving portion may be equal to or less than 10% of the natural frequency of the power receiving portion.

In the vehicle of one aspect of the invention, a coupling coefficient of the power receiving portion and the power transmitting portion may be equal to or less than 0.1.

In the vehicle of one aspect of the invention, the power receiving portion may receive electric power from the power transmitting portion through at least one of a magnetic field that is formed between the power receiving portion and the power transmitting portion and that oscillates at a specific frequency, and an electric field that is formed between the power receiving portion and the power transmitting portion and that oscillates at a specific frequency.

According to the invention, a vehicle is able to be provided that has a specific protective structure for a power receiving portion that receives electric power in a contactless manner from a power transmitting portion provided outside the vehicle, when such a power receiving portion is mounted in the vehicle.

DETAILED DESCRIPTION OF EMBODIMENTS

A vehicle provided with a power transmitting apparatus, a power receiving apparatus, and a power transfer system according to example embodiments of the invention will hereinafter be described with reference to the accompanying drawings. Also, the scope of the invention is not necessarily limited to the numbers and amounts and the like referred to in these example embodiments unless otherwise specifically stated. Further, like parts and corresponding parts will be denoted by like reference characters and redundant descriptions may not be repeated. Also, the use of the structures in the example embodiments in appropriate combinations is initially intended.

The vehicle provided with the power transfer system according to one example embodiment will be described with reference toFIG. 1.FIG. 1is a view showing a frame format of the vehicle provided with a power transmitting apparatus, a power receiving apparatus, and a power transfer system according to this example embodiment.

The power transfer system according to this example embodiment includes an electric vehicle10having a power receiving apparatus40, and an external power supply apparatus20having a power transmitting apparatus41. The power receiving apparatus40of the electric vehicle10mainly receives electric power from the power transmitting apparatus41when the electric vehicle10is stopped in a predetermined position in a parking space42provided with the power transmitting apparatus41.

A chock block, or a line indicating the parking position and the parking area is provided in the parking space42so that the electric vehicle10will stop in the predetermined position.

The external power supply apparatus20includes an alternating current (AC) power supply21, a high frequency power driver22, a control portion26, and the power transmitting apparatus41. The high frequency power driver22is connected to the AC power supply21. The control portion26controls the driving of the high frequency power driver22and the like. The power transmitting apparatus41is connected to the high frequency power driver22. The power transmitting apparatus41includes a power transmitting portion28and an electromagnetic inductive coil23. The power transmitting portion28includes a resonance coil24(also referred to as “primary coil24”), and a capacitor25that is connected to this resonance coil24. The electromagnetic inductive coil23is electrically connected to the high frequency power driver22. In the example shown inFIG. 1, the capacitor25is provided, but the capacitor25may also be omitted.

The power transmitting portion28includes an electric circuit formed from the inductance of the resonance coil24, the floating capacitance of the resonance coil24, and the capacitance of the capacitor25.

The electric vehicle10is provided with the power receiving apparatus40, a rectifier13, a DC/DC converter14, a battery15, a PCU (Power Control Unit)16, a motor unit17, and an vehicle ECU (Electronic Control Unit)18. The rectifier13is connected to the power receiving apparatus40. The DC/DC converter14is connected to the rectifier13. The battery15is connected to the DC/DC converter14. The motor unit17is connected to the PCU16. The vehicle ECU18controls the driving of the DC/DC converter14and the PCU16and the like. The electric vehicle10according to this example embodiment is a hybrid vehicle that is provided with an engine, not shown, but the vehicle of the invention may also be an electric vehicle or a fuel cell vehicle, as long as it is driven by an electric motor.

The rectifier13is connected to an electromagnetic inductive coil12. The rectifier13converts alternating current (AC current) supplied from the electromagnetic inductive coil12to direct current (DC current), which is supplied to the DC/DC converter14.

The DC/DC converter14regulates the voltage of the DC current supplied from the rectifier13, and then supplies it to the battery15. The DC/DC converter14may also be omitted. In this case, the DC/DC converter14can be substituted out by providing a matching unit for matching the impedance to the external power supply apparatus20between the power transmitting apparatus41and the high frequency power driver22.

The PCU16includes a converter that is connected to the battery15, and an inverter that is connected to the converter. The converter regulates (i.e., steps up) the DC current supplied from the battery15and supplies it to the inverter. The inverter converts the DC current supplied from the converter to AC current, then supplies it to the motor unit17.

A three-phase alternating current motor or the like may be used for the motor unit17, for example. The motor unit17is driven by AC current supplied from the inverter of the PCU16.

When the electric vehicle10is a hybrid vehicle, the electric vehicle10also includes an engine. The motor unit17includes a motor-generator that functions mainly as a generator, and a motor-generator that functions mainly as an electric motor.

The power receiving apparatus40includes a power receiving portion27and the electromagnetic inductive coil12. The power receiving portion27includes a resonance coil11(also referred to as “secondary coil11”) and a capacitor19. The resonance coil11has a floating capacitance. Therefore, the power receiving portion27has an electric circuit formed by the inductance of the resonance coil11, and the capacitance of the resonance coil11and the capacitor19. The capacitor19may also be omitted.

In the power transfer system according to this example embodiment, a difference between a natural frequency of the power transmitting portion28and a natural frequency of the power receiving portion27is equal to or less than 10% of the natural frequency of the power receiving portion27or the power transmitting portion28. Setting the natural frequencies of the power transmitting portion28and the power receiving portion27within this range enables the power transfer efficiency to be increased. However, if the difference between the natural frequencies becomes greater than 10% of the natural frequency of the power receiving portion27or the power transmitting portion28, it will result in adverse effects such as the power transfer efficiency dropping below 10% and the charging time of the battery15increasing.

Here, the natural frequency of the power transmitting portion28when the capacitor25is not provided is the oscillation frequency when an electric circuit formed by the inductance of the resonance coil24and the capacitance of the resonance coil24oscillates freely. When the capacitor25is provided, the natural frequency of the power transmitting portion28is the oscillation frequency when an electric circuit formed by the capacitance of the resonance coil24and the capacitor25, and the inductance of the resonance coil24oscillates freely. In the electric circuit, the natural frequency when braking force and electrical resistance is zero or substantially zero may also be referred to as the resonance frequency of the power transmitting portion28.

Similarly, the natural frequency of the power receiving portion27when the capacitor19is not provided is the oscillation frequency when an electric circuit formed by the inductance of the resonance coil11and the capacitance of the resonance coil11oscillates freely. When the capacitor19is provided, the natural frequency of the power receiving portion27is the oscillation frequency when an electric circuit formed by the capacitance of the resonance coil11and the capacitor19, and the inductance of the resonance coil11oscillates freely. In the electric circuit, the natural frequency when braking force and electrical resistance is zero or substantially zero may also be referred to as the resonance frequency of the power receiving portion27.

Next, simulation results from analyzing the relationship between the power transfer efficiency and the difference between the natural frequencies will be described with reference toFIGS. 2 and 3.FIG. 2is a view of a simulation model of a power transfer system. The power transfer system89includes a power transmitting apparatus90and a power receiving apparatus91. The power transmitting apparatus90includes an electromagnetic inductive coil92and a power transmitting portion93. The power transmitting portion93includes a resonance coil94and a capacitor95. The capacitor95is provided with the resonance coil94.

The power receiving apparatus91includes a power transmitting portion96and an electromagnetic inductive coil97. The power transmitting portion96includes a resonance coil99and a capacitor98. The capacitor98is connected, to the resonance coil99.

The inductance of the resonance coil94will be referred to as inductance Lt. The capacitance of the capacitor95will be referred to as capacitance C1. The inductance of the resonance coil99will be referred to as inductance Lr. The capacitance of the capacitor98will be referred to as capacitance C2. When the parameters are set in this way, the natural frequency f1 of the power transmitting portion93can be expressed by Expression (1) below. Also, the natural frequency f2 of the power transmitting portion96can be expressed by Expression (2) below.
f1=1/{2π(Lt×C1)1/2}  (1)
f2=1/{2π(Lr×C2)1/2}  (2)

Here,FIG. 3shows the relationship between the power transfer efficiency and the deviation in the natural frequencies of the power transmitting portion93and the power transmitting portion96when the inductance Lr and the capacitances C1 and C2 are fixed and only the inductance Lt is changed. In this simulation, the relative positional relationship between the resonance coil94and the resonance coil99is fixed, and the frequency of the current supplied to the power transmitting portion93is constant.

In the graph shown inFIG. 3, the horizontal axis represents the deviation (%) in the natural frequencies and the vertical axis represents the transfer efficiency (%) at a constant frequency. The deviation (%) in the natural frequencies can be expressed by Expression (3) below.
(Deviation in natural frequencies)={(f1−f2)/f2}×100(%)  (3)

As is evident fromFIG. 3, when the deviation (%) in the natural frequencies is ±0%, the power transfer efficiency is close to 100%. When the deviation (%) in the natural frequencies is ±5%, the power transfer efficiency is 40%. When the deviation (%) in the natural frequencies is ±10%, the power transfer efficiency is 10%. When the deviation (%) in the natural frequencies is ±15%, the power transfer efficiency is 5%. In other words, it is evident that the power transfer efficiency is able to be increased by setting the natural frequencies of the power transmitting portion and the power receiving portion such that the absolute value of the deviation (%) in the natural frequencies (i.e., the difference between the natural frequencies) is in a range of equal to or less than 10% of the natural frequency of the power transmitting portion96. Furthermore, it, is evident that the power transfer efficiency can be further increased by setting the natural frequencies of the power transmitting portion and the power receiving portion such that the absolute value of the deviation (%) in the natural frequencies is equal to or less than 5% of the natural frequency of the power transmitting portion96. Electromagnetic field analysis software (JMAG (registered trademark) by JSOL Corporation) was used for the simulation software.

Next, operation of the power transfer system according to the example embodiment will be described. InFIG. 1, AC current is supplied from the high frequency power driver22to the electromagnetic inductive coil23. When a predetermined AC current flows to the electromagnetic inductive coil23, AC current also flows to the resonance coil24by electromagnetic induction. At this time, power is supplied to the electromagnetic inductive coil23such that the frequency of the AC current flowing through the resonance coil24becomes a specific frequency.

When current of a predetermined frequency flows to the resonance coil24, an electromagnetic field that oscillates at a specific frequency is formed around the resonance coil24.

The resonance coil11is arranged within a predetermined distance from the resonance coil24, and receives power from the electromagnetic field formed around the resonance coil24.

In this example embodiment, a helical coil is employed for both, the resonance coil11and the resonance coil24. Therefore, a magnetic field that oscillates at a specific frequency is mainly formed around the resonance coil24, and the resonance coil11receives power from this magnetic field.

Here, the magnetic field of a specific frequency that is formed around the resonance coil24will be described. With the magnetic field of a specific frequency, there is typically a connection between the power transfer efficiency and the frequency of the current supplied to the resonance coil24. Therefore, first the relationship between the power transfer efficiency and the frequency of the current supplied to the resonance coil24will be described. The power transfer efficiency when transferring power from the resonance coil24to the resonance coil11changes due to various factors, such as the distance between the resonance coil24and the resonance coil11. For example, the natural frequency (resonance frequency) of the power transmitting portion28and the power receiving portion27will be referred to as natural frequency fit, the frequency of the current supplied to the resonance coil24will be referred to as frequency f3, and an air gap between the resonance coil11and the resonance coil24will be referred to as air gap AG.

FIG. 4is a graph showing the relationship between the power transfer efficiency when the air gap AG is changed, and the frequency f3 of the current supplied to the resonance coil24, when the natural frequency f0 is fixed.

In the graph shown inFIG. 4, the horizontal axis represents the frequency f3 of the current supplied to the resonance coil24, and the vertical axis represents the power transfer efficiency (%). The efficiency curve L1 shows a frame format of the relationship between the power transfer efficiency when the air gap AG is small, and the frequency f3 of the current supplied to the resonance coil24. As shown by this efficiency curve L1, when the air gap AG is small, the peak of the power transfer efficiency occurs at frequencies f4 and f5 (f4<f5). When the air gap AG is increased, the two peaks when the power transfer efficiency increases change so as to become closer together. Also, as shown by the efficiency curve L2, when the air gap AG becomes greater than a predetermined distance, the peak of the power transfer efficiency becomes a single peak. The power transfer efficiency peaks when the frequency of the current supplied to the resonance coil24is a frequency f6. When the air gap AG is increased so that it is even greater than it is with the efficiency curve L2, the peak of the power transfer efficiency becomes smaller, as shown by the efficiency curve L3.

For example, a first method described below is conceivable as a method for improving the power transfer efficiency. This first method involves keeping the frequency of the current supplied to the resonance coil24shown inFIG. 1constant and changing the capacitance of the capacitor25and the capacitor19to match the air gap AG. Accordingly, a method that involves changing the characteristic of the power transfer efficiency between the power transmitting portion28and the power receiving portion27is possible. More specifically, the capacitance of the capacitor25and the capacitor19is adjusted such that the power transfer efficiency peaks while the frequency of the current supplied to the resonance coil24is kept constant. With this method, the frequency of the current that flows to the resonance coil24and the resonance coil11is constant regardless of the size of the air gap AG A method that involves using the matching unit provided between the power transmitting apparatus41and the high frequency power driver22, or a method that involves using the DC/DC converter14, or the like may also be employed as a method for changing the characteristic of the power transfer efficiency.

Also, a second method involves adjusting the frequency of the current supplied to the resonance coil24based on the size of the air gap AG. For example, when the power transfer characteristic is that of the efficiency curve L1 inFIG. 4, current in which the frequency is the frequency f4 or the frequency f5 is supplied to the resonance coil24. Also, when the frequency characteristic is that of the efficiency curves L2 and L3, current in which the frequency is the frequency f6 is supplied to the resonance coil24. In this case, the frequency of the current that flows to the resonance coil24and the resonance coil11is changed to match the size of the air gap AG.

In the first method, the frequency of the current that flows through the resonance coil24is a constant frequency that is fixed. In the second method, the frequency of the current that flows through the resonance coil24is a frequency that changes appropriately according to the air gap AG. Current of a specific frequency set so that the power transfer efficiency increases is supplied to the resonance coil24according to the first method and the second method or the like. A magnetic field (electromagnetic field) that oscillates at a specific frequency is formed around the resonance coil24by current of the specific frequency flowing to the resonance coil24. The power receiving portion27receives power from the power transmitting portion28via this magnetic field. The magnetic field is formed between the power receiving portion27and the power transmitting portion28, and oscillates at a specific frequency. Therefore, the magnetic field that oscillates at a specific frequency is not limited to a magnetic field of a fixed frequency. In the example described above, the frequency of the current supplied to the resonance coil24is set focusing on the air gap AG. However, the power transfer efficiency may also change according to other factors such as a deviation in the horizontal direction of the resonance coil24and the resonance coil11, and the frequency of the current supplied to the resonance coil24may be adjusted based on these other factors.

In this example embodiment, an example in which a helical coil is used as the resonance coil is described. However, if an antenna such as a meander line antenna is used as the resonance coil, an electric field of a specific frequency will be formed around the resonance coil24by current of a specific frequency flowing to the resonance coil24. Also, power transfer is performed between the power transmitting portion28and the power receiving portion27via this electric field.

In the power transfer system according to this example embodiment, power transmitting efficiency and power receiving efficiency are improved by using a near field (evanescent field) where the static electromagnetic field of the electromagnetic field is dominant.FIG. 5is a graph showing the relationship between the strength of the electromagnetic field and the distance from the current source or the magnetic current source. Referring toFIG. 5, the electromagnetic field is formed of three components. Curve k1 is a component that is inversely proportional to the distance from the wave source, and will be referred to as a radiated electromagnetic field. Curve k2 is a component that is inversely proportional to the square of the distance from the wave source, and will be referred to as an induction electromagnetic field. Also, curve k3 is a component that is inversely proportional to the cube of the distance from the wave source, and will be referred to as a static electromagnetic field. If the wavelength of the electromagnetic field is λ, the distance at which the strengths of the radiated electromagnetic field, the induction electromagnetic field, and the static electromagnetic field are substantially equal can be expressed as λ/2π.

The static electromagnetic field is a region where the strength of the electromagnetic waves sharply decreases with distance from the wave source. With the power transfer system (resonance method) according to the example embodiment, the power transfer of energy (electric power) is performed by using near-field (evanescent field) where this static electromagnetic field that is dominant. In other words, in the near filed in which the electrostatic field is dominant, the power transmitting portion28and the power receiving portion27(e.g., a pair of LC resonance coils) having the natural frequencies that are close together are resonated to transfers energy (electric power) from the power transmitting portion28to the other power receiving portion27. This static electromagnetic field does not propagate energy far away, the resonance method achieves less energy loss in electric power transmission as compared with the case of an electromagnetic waves that transfer energy (electric power) using the radiated electromagnetic field, which propagates energy, far away.

In this way, in this power transfer method, power is transferred in a contactless manner between the power transmitting portion and the power receiving portion by resonating the power transmitting portion and the power receiving portion by the electromagnetic field. This electromagnetic field formed between the power receiving portion and the power transmitting portion may be referred to as a near field resonance coupling field. Also, a coupling coefficient k between the power transmitting portion and the power receiving portion is approximately equal to or less than 0.3, and preferably equal to or less than 0.1, for example. Naturally, a coupling coefficient k within a range of approximately 0.1 to 0.3 may also be used. The coupling coefficient k is not limited to such a value. That is, the coupling coefficient k may be any of a variety of values that yield good power transfer.

The coupling of the power transmitting portion28and the power receiving portion27in the power transfer in this example embodiment is referred to as magnetic resonance coupling, near field resonance coupling, electromagnetic resonance coupling, or electric field resonance coupling, for example.

Electromagnetic resonance coupling is coupling that includes both magnetic resonance coupling and electric field resonance coupling.

A coil-shaped antenna is used for both the resonance coil24of the power transmitting portion28and the resonance coil11of the power receiving portion27described in this specification, so the power transmitting portion28and the power receiving portion27are mainly coupled by a magnetic field. At this time, the power transmitting portion28and the power receiving portion27are coupled by magnetic resonance coupling.

An antenna such as a meander line antenna may be used for each of the resonance coils24and11, for example. In this case, the power transmitting portion28and the power receiving portion27are mainly coupled by an electric field. At this time, the power transmitting portion28and the power receiving portion27are coupled by electric field resonance coupling.

Next, the specific structure of a power receiving, unit1000mounted in the electric vehicle10in the example embodiment will be described with reference toFIGS. 6 to 10.FIG. 6is a bottom view of the electric vehicle10in the example embodiment,FIG. 7is an exploded perspective view of the power receiving unit1000in the example embodiment,FIG. 8is a sectional view of the power receiving unit1000in the example embodiment,FIG. 9is a partial enlarged sectional view of the region encircled by IX inFIG. 8, andFIG. 10is a plan view of a seal structure employed in the power receiving unit1000in the example embodiment.

As shown inFIG. 6, a region from a front end of the electric vehicle10to a rear end of a front tire160F will be referred to as a “front portion”, a region from the rear end of the front tire160F to a front end of a rear tire160R will be referred to as a “center portion”, and a region from the front end of the rear tire160R to a rear end of the electric vehicle10will be referred to as a “rear portion”.

The same applies to the description below. Also, when the electric vehicle10is stopped on a horizontal surface (plane), upward in the vertical direction will be referred to as “upper side”, “upper”, or “above”, and downward in the vertical direction will be referred to as “lower side”, “lower”, or “below”. Also, the direction of the arrows pointing in a direction parallel to the horizontal surface will be referred to as “horizontal direction”.

Referring toFIG. 6, in the electric vehicle10in this example embodiment, the power receiving unit1000is mounted below a rear floor panel510at the rear portion of the electric vehicle10. The mounting position of the power receiving unit1000is not limited to being at the rear portion of the electric vehicle10. That is, the power receiving unit1000may also be mounted below a center floor panel520of the center portion, or below an engine under floor panel530of the front portion.

Referring now toFIG. 7, the power receiving unit1000includes the power receiving apparatus40, an electromagnetic shield200, a power receiving portion cover100(a first cover), and an undercover300(a second cover). The power receiving unit1000is mounted below the rear floor panel510provided in the electric vehicle10. The power receiving apparatus40includes the power receiving portion27that receives power in a contactless manner from the power transmitting portion28that is externally provided. The electromagnetic shield200prevents the electromagnetic field from passing through. The power receiving portion cover100covers the power receiving portion27and allows the electromagnetic field to pass through. The undercover300covers the power receiving portion cover100and allows the electromagnetic field to pass through.

In the example of the structure shown inFIG. 7, the electromagnetic shield200is open from below (i.e., on a lower side) where the power receiving portion27is located, and surrounds the power receiving portion27from above and the side in the horizontal direction, when the power receiving portion27is viewed from above. That is, the electromagnetic shield200surrounds the upper side and the side, in the horizontal direction, of the power receiving portion27. The power receiving portion cover100is provided covering the power receiving portion27, in a position below the power receiving portion27. The undercover300is provided covering the power receiving portion cover100, in a position below the power receiving portion cover100.

The power receiving apparatus40includes the power receiving portion27and the electromagnetic inductive coil12that is octagonal. The power receiving portion27includes the resonance coil11that is octagonal and the capacitor19. The resonance coil11and the electromagnetic inductive coil12are fixed to the electromagnetic shield200using a resin support member110.

The shapes of the resonance coil11and the electromagnetic inductive coil12are not limited to being octagonal. Alternatively, they may be circular, square, rectangular, or another shape. Similarly, the shape of the electromagnetic shield200is not limited to the shape shown in the drawing.

Also, the positional relationship of the resonance coil11and the electromagnetic inductive coil12shown in the drawing is one in which the resonance coil11and the electromagnetic inductive coil12are stacked in the vertical direction, but the positional relationship of these is not limited to this. That is, a structure in which the electromagnetic inductive coil12is arranged to the outside of the resonance coil11in the radial direction of the coil may be employed, or a structure in which the resonance coil11is arranged to the outside of the electromagnetic inductive coil12may be employed. Also, a structure in which the electromagnetic inductive coil12is not provided may also be employed.

In this example embodiment, the rectifier13and the capacitor19are arranged to the inside of the resonance coil11and the electromagnetic inductive coil12. The positional relationship of the rectifier13and the DC/DC capacitor19is not limited to this, however.

Next, the specific shapes of the electromagnetic shield200, the power receiving portion cover100, and the undercover300will be described with reference to bothFIG. 7andFIG. 8, but mainlyFIG. 8.

The electromagnetic shield200includes a base portion202and a side wall portion201. The base portion202is positioned on the rear floor panel510side, which is the upper side when viewed from the resonance coil11. The side wall portion201surrounds the resonance coil11from the side in the horizontal direction when viewed from the resonance coil11, and surrounds the base portion202at an edge portion of the base portion202, and extends downward from the base portion202.

The rectifier13and the capacitor19are fixed to the base portion202. Also, the resonance coil11and the electromagnetic inductive coil12are fixed to the base portion202using the support member110. An inlet203for taking in cooling air and an outlet204for discharging cooling air are provided in the base portion202.

An inlet opening501and an outlet opening502are provided beforehand in the rear floor panel510. The inlet203protrudes from the inlet opening501, and the outlet204protrudes from the outlet opening502. A cooling system, not shown, that is mounted in the electric vehicle10is connected to the inlet203and the outlet204.

The electromagnetic shield200surrounds the power receiving portion27from above and the side in the horizontal direction, when viewed from the power receiving portion27. The electromagnetic shield200is made of metal material such as steel, aluminum, or copper in order to prevent the electromagnetic field from passing through. When the electromagnetic field reaches the electromagnetic shield200, the electromagnetic field is converted into an eddy current, so an electromagnetic shielding effect is displayed. In order to efficiently convert the electromagnetic waves that have reached the electromagnetic shield200into an eddy current and improve the shielding effect, the electromagnetic shield200is preferably made of material having low impedance. That is, the electromagnetic shield200is preferably made of copper.

A shielding process may also be applied to the surface of the material to give the material a shielding effect. Examples of such a shielding process include a plating process, an application process, and a thin film adhesion process and the like.

The power receiving portion cover100is fixed to the electromagnetic shield200so as to cover the resonance coil11. More specifically, the power receiving portion cover100has a bottom portion101, a side wall portion102, and a flange portion103. The bottom portion101is positioned below the resonance coil11. The side wall portion102surrounds the bottom portion101at an edge portion of the bottom portion101and extends upward from the bottom portion101. The flange portion103extends toward the outside that is the side opposite the resonance coil11, at an upper end of the side wall portion102.

In this example embodiment, the side wall portion102and the flange portion103are positioned to the inside, i.e., the resonance coil11side, of the side wall portion201of the electromagnetic shield200so as to cover the resonance coil11. Also, the flange portion103is fixed to the base portion202of the electromagnetic shield200using bolts B.

Referring now toFIGS. 9 and 10, bolt holes103hare provided in the flange portion103at predetermined intervals. Also, a seal member120is arranged on the flange portion103. This seal member120is used so that there will not be a gap between the flange portion103and the base portion202when bolting the flange portion103to the base portion202. Some examples of the material of which this seal member120is formed include flexible resin material and elastic rubber material.

Interposing this seal member120between the flange portion103and the base portion202make it possible to inhibit gas and liquid from getting in from the outside. Also, the resonance coil11, the electromagnetic inductive coil12, the rectifier13, and the capacitor19are able to be housed in a highly airtight space A by the power receiving portion cover100and the electromagnetic shield200. Moreover, the cooling effect using the inlet203and the outlet204is also able to be increased.

The power receiving portion cover100may be made of resin material because it is all right to allow the electromagnetic field to pass through. Therefore, the power receiving portion cover100may be integrally formed by a molded article made of resin material. As a result, the degree of freedom in design, such as the shape, of the power receiving portion cover100is able to be increased.

The power receiving portion cover100is positioned inside the undercover300that will be described later. The resonance coil11, the electromagnetic inductive coil12, the rectifier13, and the capacitor19are thus doubly covered by the power receiving portion cover100and the undercover300. Therefore, liquid and gas are able to be more reliably inhibited from getting into the power receiving portion cover100from the outside, even if the seal member120is not provided on the undercover300. Accordingly, it can be expected that even better performance in terms of inhibiting gas and liquid from getting in from the outside will be obtained by providing the seal member120.

Referring back toFIG. 8again, the undercover300is fixed to the rear floor panel510so as to cover the electromagnetic shield200and the power receiving portion cover100. More specifically, the undercover300includes an outermost bottom portion301, an outermost side wall portion302, and an outermost flange portion303. The outermost bottom portion301is positioned below the bottom portion101of the power receiving portion cover100. The outermost side wall portion302surrounds the outermost bottom portion301at an edge portion of the outermost bottom portion301, and extends upward from the outermost bottom portion301. The outermost flange portion303extends toward the outside that is the side opposite the resonance coil11, at an upper end of the outermost side wall portion302.

In this example embodiment, although not shown, the outermost flange portion303of the outermost side wall portion302is fixed to the rear floor panel510using bolts or the like. A molded article made of resin material may be used for the undercover300, because it is all right to allow the electromagnetic field to pass through.

The resonance coil11, the electromagnetic inductive coil12, the rectifier13, and the capacitor19can be expected to be waterproof and airtight by the power receiving portion cover100that is positioned to the inside of the undercover300. Therefore, the undercover300may function to prevent those components, i.e., the resonance coil11, the electromagnetic inductive coil12, the rectifier13, and the capacitor19, from deforming when subjected to a high pressure car wash, and from being damaged as a result of being struck by flying stones, and in addition, may have an exterior design function, unlike the power receiving portion cover100.

Also, using the bolts B to attach the power receiving portion cover100and the undercover300facilitates the work of attaching and detaching the power receiving portion cover100and the undercover300. As a result, even after the power receiving portion cover100and the undercover300have been attached, they (i.e., the power receiving portion cover100and the undercover300) can easily be removed, which makes it easy to adjust the resonance coil11and the electromagnetic inductive coil12and the like.

In this, way, the example embodiment makes it possible to provide the electric vehicle10that has a specific structure for protecting the power receiving portion27, i.e., has the structure that includes the electromagnetic shield200that prevents the electromagnetic field from passing through, the power receiving portion cover100that allows the magnetic field to pass through and is positioned below the power receiving portion27that includes the resonance coil11, and covers the power receiving portion27, and the undercover300that allows the electromagnetic field to pass through and is positioned below the power receiving portion cover100, and covers the power receiving portion cover100.

In the example embodiment described above, a structure in which the base portion202of the electromagnetic shield200directly contacts the lower surface of the rear floor panel510is employed, but the invention is not limited to this structure. For example, as shown inFIG. 11, a structure in which a space S is provided between the lower surface of the rear floor panel510and the upper surface of the base portion202of the electromagnetic shield200may also be employed.

Also, the structures of the power receiving portion cover100shown inFIGS. 8 and 11are structures in which the side wall portion102and the flange portion103are provided, but the invention is not limited to this. For example, as shown inFIG. 12, a structure in which the power receiving portion cover100formed only of the bottom portion101is used, and an outer peripheral edge portion of the bottom portion101is fixed to the side wall portion201of the electromagnetic shield200via the seal member120, may be employed.

Furthermore, as another structure, as shown inFIG. 13, a structure may be employed in which the side wall portion102of the power receiving portion cover100is fixed to the rear floor panel510at an outer position at a side opposite, with respect to the side wall portion201of the electromagnetic shield200, to the power receiving portion27, such that the side wall portion201is sandwiched between the power receiving portion27and the side wall portion102.

Also, in the example embodiment described above, a case is described in which the base portion202is provided on the electromagnetic shield200. Alternatively, however, a structure may be employed in which the rear floor panel510is used as the base portion202, and the side wall portion201that extends downward from the rear floor panel510is provided on the rear floor panel510.

The example embodiments disclosed herein are in all respects merely examples and are not limiting. The scope of the invention is indicated not by the foregoing description but by the scope of the claims for patent, and includes all modifications that are within the scope and meanings equivalent to the scope of the claims for patent.