Vehicle power source system

Abstract

A vehicle power source system includes a plurality of module groups each including a plurality of battery modules and disposed separately from each other, and a cooling circuit including a plurality of module group cooling units which are configured to respectively cool the plurality of module groups. The plurality of module group cooling units are connected in series. Each of the plurality of module group cooling units includes a plurality of module cooling units, each of which is configured to cool one or more of the battery modules. In each of the plurality of module group cooling units, the plurality of module cooling units are connected in parallel.

Claims

1. A vehicle power source system comprising: a first module group including a plurality of battery modules; a second module group including a plurality of battery modules and disposed separately from the first module group; a third module group including a plurality of battery modules; a high-voltage equipment; and a cooling circuit including: a first module group cooling unit which is configured to cool the first module group; a second module group cooling unit which is configured to cool the second module group; a third module group cooling unit which is configured to cool the third module group; a high-voltage equipment cooling unit which is disposed at a downstream side of the first module group cooling unit and the second module group cooling unit and is configured to cool the high-voltage equipment; and a bypass flow path which is configured to connect an upstream side of the first module group cooling unit and the second module group cooling unit to an upstream side of the high-voltage equipment cooling unit and the downstream side of the first module group cooling unit and the second module group cooling unit, wherein the third module group cooling unit, the second module group cooling unit, and the first module group cooling unit are connected in series in this order from an upstream side thereof, wherein each of the first module group cooling unit, the second module group cooling unit, and the third module group cooling unit includes a plurality of module cooling units, each of which is configured to cool one or more of the battery modules, wherein the plurality of module cooling units of the first module group cooling unit are connected in parallel, wherein the plurality of module cooling units of the second module group cooling unit are connected in parallel, and wherein the first to third module groups and the first to third module group cooling units are disposed below a floor panel.

2. The vehicle power source system according to claim 1, wherein the cooling circuit includes a flow path switching device provided at the upstream side of the first module group cooling unit and the second module group cooling unit.

3. The vehicle power source system according to claim 1, wherein the high-voltage equipment includes a first high-voltage equipment and a second high-voltage equipment having a greater heat value than that of the first high-voltage equipment, wherein the cooling circuit further includes a first high-voltage equipment cooling unit which is configured to cool the first high-voltage equipment and a second high-voltage equipment cooling unit which is configured to cool the second high-voltage equipment, and wherein the first high-voltage equipment cooling unit and the second high-voltage equipment cooling unit are connected in series in this order from an upstream side thereof.

4. The vehicle power source system according to claim 1, wherein a first battery unit includes the first module group and the second module group, wherein a second battery unit includes the third module group, and wherein the first battery unit and the second battery unit are independently fixed to a framework member of a vehicle.

5. The vehicle power source system according to claim 4, wherein the cooling circuit further includes a cooling internal piping provided inside the first battery unit and the second battery unit, and a cooling external piping provided outside the first battery unit and the second battery unit, wherein at least a part of the cooling external piping is disposed at one vehicle width side of the first battery unit, and wherein the cooling external piping is not provided at another vehicle width side of the first battery unit.

6. The vehicle power source system according to claim 5, wherein an exhaust pipe is provided at the other vehicle width side of the first battery unit.

7. The vehicle power source system according to claim 5, wherein the high-voltage equipment is disposed inside the first battery unit.

8. The vehicle power source system according to claim 7, wherein the high-voltage equipment and a high-voltage wiring for connecting the high-voltage equipment to the first module group and the second module group are disposed at a vehicle width center of the first battery unit.

9. The vehicle power source system according to claim 4, wherein the first module group is a front module group disposed below a front seat, wherein the second module group is a middle module group disposed below a rear seat, and wherein the third module group is a rear module group disposed rear of the vehicle.

10. The vehicle power source system according to claim 1, wherein the plurality of battery modules of the third module group include a plurality of down-stage battery modules located at a lower stage and a plurality of upper-stage battery modules located at an upper stage, wherein the plurality of module cooling units for cooling the third module group include a plurality of down-stage module cooling units which are configured to respectively cool the plurality of down-stage battery modules and a plurality of upper-stage module cooling units which are configured to respectively cool the plurality of upper-stage battery modules, wherein the plurality of down-stage module cooling units are connected in parallel, wherein the plurality of upper-stage module cooling units are connected in parallel, and wherein the plurality of down-stage module cooling units and the plurality of upper-stage module cooling units are connected in series.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a schematic side view of a vehicle on which a vehicle power source system according to an embodiment of the present invention is mounted.

(2) FIG. 2 is an exploded perspective view schematically showing a first battery unit of the vehicle power source system shown in FIG. 1.

(3) FIG. 3 is an exploded perspective view schematically showing a second battery unit of the vehicle power source system shown in FIG. 1.

(4) FIG. 4 is a circuit diagram showing a configuration of a cooling circuit of the vehicle power source system according to the embodiment of the present invention.

(5) FIG. 5 is a schematic block diagram of the cooling circuit of the vehicle power source system according to the embodiment of the present invention.

(6) FIG. 6 is a schematic block diagram showing a flow of a refrigerant when a three-way solenoid valve is off in the cooling circuit shown in FIG. 5.

(7) FIG. 7 is a schematic block diagram showing a flow of the refrigerant when the three-way solenoid valve is on in the cooling circuit shown in FIG. 5.

(8) FIG. 8 is a circuit diagram showing a configuration of a cooling circuit of a vehicle power source system according to a modification.

DETAILED DESCRIPTION OF EMBODIMENT

(9) Hereinafter, a vehicle power source system according to an embodiment of the present invention will be described based on the accompanying drawings. The drawings should be seen in a direction in which reference numerals appear normal.

(10) [Vehicle Power Source System]

(11) As shown in FIG. 1, a vehicle power source system 1 according to an embodiment of the present invention mainly includes a battery 30, a high-voltage equipment 20, and a cooling circuit 100 for cooling these constituent components and is mounted on a vehicle V such as a hybrid vehicle, an electric vehicle and a fuel cell vehicle.

(12) [Battery]

(13) The battery 30 includes a front module group 31, a middle module group 32, and a rear module group 33 which are disposed separately from each other. A plurality of battery modules 30a in which a plurality of battery cells are stacked in a cuboid shape are disposed collectively in each of the module groups 31 to 33.

(14) Specifically, as shown in FIG. 2, the front module group 31 includes a total of six battery modules 30a which are arranged two in a left-right direction and three in a front-rear direction, while a longitudinal direction of each battery module 30a is directed in the left-right direction (vehicle width direction). As shown in FIG. 2, the middle module group 32 includes a total of eight battery modules 30a in which six battery modules 30a are arranged two in the left-right direction and three in the front-rear direction, and additional two battery modules 30a are respectively arranged on the two battery modules 30a in a frontmost row in the left-right direction, while a longitudinal direction of each battery module 30a is directed in the left-right direction (vehicle width direction). As shown in FIG. 3, the rear module group 33 includes a total of eight battery modules 30a in which four battery modules 30a are arranged in the left-right direction, and additional four battery modules 30a are respectively arranged on the four battery modules 30a, while a longitudinal direction of each battery module 30a is directed in the front-rear direction.

(15) [High-Voltage Equipment]

(16) The high-voltage equipment 20 includes a charger 21 and a DC-DC converter 22. The charger 21 is a high-voltage equipment which charges the battery 30 with electric power supplied from an external power source, and the DC-DC converter 22 is a high-voltage equipment which converts direct current power. The charger 21 and the DC-DC converter 22 are more heat-resistant than the battery 30, and control temperatures thereof are set higher than that of the battery 30. For example, an upper limit temperature of the high-voltage battery 30 is set at 60 C., upper limit temperatures of the charger 21 and the DC-DC converter 22 are set at 80 C., and therefore, under a high-temperature environment, the battery 30 needs to be cooled in higher priority than the charger 21 and the DC-DC converter 22. Incidentally, the charger 21 becomes higher temperature in charging, there may be a situation where the battery 30 does not need to be cooled, and only the charger 21 and the DC-DC converter 22 need to be cooled.

(17) [First Battery Unit]

(18) As shown in FIGS. 1 and 2, the front module group 31, the middle module group 32, the DC-DC converter 22, a part of the cooling circuit 100 (hereinafter, also referred to as an interior cooling circuit 100A), and a case 50 for accommodating those constituent components are unitized to configure a first battery unit 10, which is disposed below a floor panel 3 forming a floor surface of a passenger compartment 2. The interior cooling circuit 100A is shown in FIG. 4.

(19) The case 50 includes a bottom plate 51 on which the front module group 31, the middle module group 32, the DC-DC converter 22 are mounted, and a cover 52 which covers those constituent components from above. A plurality of brackets 53 which extend in the left-right direction below the bottom plate 51 are fastened to bottom faces of a pair of floor frames (not shown) from below which are provided parallel to an inner of side sills provided on both sides of the vehicle V, so that the first battery unit 10 is installed below the floor panel 3.

(20) Accordingly, the first battery unit 10 is fixed to the floor frames (not shown), so that the front module group 31 is disposed below a front seat 4 and the middle module group 32 is disposed below a rear seat 5. The battery modules 30a in the frontmost row of the middle module group 32 in which two battery modules 30a are disposed to be overlapped are located under a front portion of a seat cushion of the rear seat 5. The DC-DC converter 22 is disposed between the front module group 31 and the middle module group 32 at a vehicle width center of the first battery unit 10. A high-voltage wiring (not shown) for connecting the front module group 31 and the middle module group 32 to the DC-DC converter 22 is also disposed at the vehicle width center of the first battery unit 10. Left and right battery ECUs 40 are disposed on the battery modules 30a in a second row and a third row from the front of the middle module group 32. The battery ECUs 40 are battery controllers which control the charging, discharging and temperatures of the front module group 31 and the middle module group 32.

(21) [Second Battery Unit]

(22) As shown in FIGS. 1 and 3, the rear module group 33, a part of the cooling circuit 100 (hereinafter, also referred to as an interior cooling circuit 100B), and a case 55 for accommodating those constituent components are unitized to configure a second battery unit 60, which is disposed below the floor panel 3 forming the floor surface of a luggage compartment 6. The internal cooling circuit 100B is shown in FIG. 4.

(23) The case 55 includes a bottom plate 56 on which the rear module group 33 is mounted, and a cover 57 which covers the rear module group 33 from above. A plurality of brackets 58 which extend in the left-right direction below the bottom plate 56 are fastened to rear frames (not shown) which are formed to surround the second battery unit 60, and the rear frames are fastened to rear side members (not shown), so that the second battery unit 60 is installed below the floor panel 3.

(24) Accordingly, the second battery unit 60 is fixed to the rear side members (not shown), so that the rear module group 33 is disposed below the luggage compartment 6. A battery ECU 41 is disposed on the battery modules 30a of the rear module group 33. The battery ECU 41 is a battery controller which controls the charging, discharging and temperature of the rear module group 33.

(25) [Configuration of Cooling Circuit]

(26) A radiator 101 and a cooling pump 102 which configure the cooling circuit 100 are disposed in a so-called engine room 7 at the front of the first battery unit 10 along with a motor for driving the vehicle (not shown) and the charger 21 which are connected to the battery 30. The cooling circuit 100 is divided into the interior cooling circuit 100A disposed inside the first battery unit 10, the interior cooling circuit 100B disposed inside the second battery unit 60, and an exterior cooling circuit 1000 disposed outside the first battery unit 10 and the second battery unit 60.

(27) As shown in FIGS. 4 and 5, in the cooling circuit 100, the radiator 101, the cooling pump 102, a battery cooling unit 130, a DC-DC converter cooling unit 122, and a charger cooling unit 121 are connected in series by an external piping 103 which is disposed outside the first battery unit 10 and the second battery unit 60, and an internal piping 104 which is disposed inside the first battery unit 10 and the second battery unit 60, so that a refrigerant circulation path is formed.

(28) As shown in FIG. 4, the radiator 101 radiates heat of a refrigerant which flows in from an inlet port 101a and discharges the refrigerant which is cooled by the heat radiation from an outlet port 101b. The inlet port 101a of the radiator 101 is connected to an outlet port 121b of the charger cooling unit 121 via a first external piping 103a. The outlet port 101b of the radiator 101 is connected to a suction port 102a of the cooling pump 102 via a second external piping 103b.

(29) The cooling pump 102 discharges the refrigerant suctioned in from the suction port 102a from a discharge port 102b according to a driving of an electric motor (not shown). The discharge port 102b of the cooling pump 102 is connected to an inlet port 133b of the rear module group 133 described later, which is an inlet port of the battery cooling unit 130, via a third external piping 103c and a fourth external piping 103d.

(30) The battery cooling unit 130 includes a plurality of module group cooling units 131 to 133 for respectively cooling the plurality of module groups 31 to 33. A front module group cooling unit 131 for cooling the front module group 31 is configured such that cooling jackets 131a for cooling each set of two battery modules 30a arranged in the left-right direction are arranged three in the front-rear direction, upstream sides of these cooling jackets 131a are connected in parallel via a first internal piping 104a, and downstream sides of these cooling jackets 131a are connected in parallel via a second internal piping 104b.

(31) A middle module group cooling unit 132 for cooling the middle module group 32 is configured such that cooling jackets 132a for cooling each set of two battery modules 30a arranged in the left-right direction are arranged three in the front-rear direction, and a cooling jacket 132a for cooling a set of two battery modules 30a at a second stage is disposed above the frontmost row cooling jackets 132a. Upstream sides of these four cooling jackets 132a are connected in parallel via a third internal piping 104c, and downstream sides of these cooling jackets 132a are connected in parallel via a fourth internal piping 104d. Incidentally, the cooling jacket 132a in the second stage and the three cooling jackets 132a in a first stage are described to be arranged together in FIG. 4.

(32) A rear module group cooling unit 133 for cooling the rear module group 33 is configured such that cooling jackets 133a for cooling each battery module 30a in a first stage are arranged four in the left-right direction, and cooling jackets 133a for cooling each battery module 30a in a second stage thereon are arranged four in the left-right direction. Upstream sides of these eight cooling jackets 133a are connected in parallel via a fifth internal piping 104c, and downstream sides of these cooling jackets 133a are connected in parallel via a sixth internal piping 104f. Incidentally, the four cooling jackets 133a in the second stage and the four cooling jackets 133a in the first stage are described to be arranged together in FIG. 4.

(33) In the battery cooling unit 130, the plurality of module group cooling units 131 to 133 are disposed in series. Specifically, an outlet port 133c of the rear module group cooling unit 133 is connected to an inlet port 132b of the middle module group cooling unit 132 via a seventh internal piping 104g and a fifth external piping 103e, and an outlet port 132c of the middle module group cooling unit 132 is connected to an inlet port 131b of the front module group cooling unit 131 vi an eighth internal piping 104h.

(34) The DC-DC converter cooling unit 122 is a cooling jacket which is incorporated in the DC-DC converter 22 or a cooling jacket which is disposed adjacent to the DC-DC converter 22, and the charger cooling unit 121 is a cooling jacket which is incorporated in the charger 21 or a cooling jacket which is disposed adjacent to the charger 21. The DC-DC converter cooling unit 122 and the charger cooling unit 121 are connected to each other in series and are disposed at a downstream side of the battery cooling unit 130.

(35) Specifically, an inlet port 122a of the DC-DC converter cooling unit 122 is connected to an outlet port 131c of the front module group cooling unit 131 which is an outlet port of the battery cooling unit 130 via a ninth inner piping 104i, and an outlet port 122b of the DC-DC converter cooling unit 122 is connected to an inlet port 121a of the charger cooling unit 121 via a tenth internal piping 104j and a sixth external piping 103f.

(36) In the cooling circuit 100, in connecting the DC-DC converter cooling unit 122 and the charger cooling unit 121 in series, the charger cooling unit 121 for cooling the charger 21 which has a greater heat value than that of the DC-DC converter 22 is disposed at a downstream side of the DC-DC converter cooling unit 122 for cooling the DC-DC converter 22. In general, since a heat value of a charger is greater than that of a DC-DC converter, the DC-DC converter cooling unit 122 and the charger cooling unit 121 are connected in series in this order from the upstream side thereof, so that the DC-DC converter 22 having a smaller heat value is firstly cooled. Accordingly, the cooling efficiency can be enhanced.

(37) Further, in the cooling circuit 100, a bypass flow path 105 is provided which connects an upstream side of the battery cooling unit 130 to an upstream side of the high-voltage equipment cooling unit 120 (the DC-DC converter cooling unit 122 and the charger cooling unit 121) and the downstream side of the battery cooling unit 130. Specifically, a connecting portion between the third external piping 103c and the fourth external piping 103d is referred to as a branch portion 114, and the branch portion 114 is connected to the outlet port 131c of the front module group cooling unit 131 which is the outlet port of the battery cooling unit 130 via a seventh external piping 103g which configures the bypass flow path 105. Then, a three-way solenoid valve 106, which functions as a flow path switching device, is provided at the branch portion 114.

(38) When the three-way solenoid valve 106 is off, the third external piping 103c and the fourth external piping 103d are connected such that the refrigerant discharged from the cooling pump 102 is supplied to the battery cooling unit 130, while the third external piping 103c is disconnected from the bypass flow path 105 (the seventh external piping 103g) such that the direct supply of the refrigerant to the high-voltage equipment cooling unit 120 (the DC-DC converter cooling unit 122 and the charger cooling unit 121) is cut off. When the three-way solenoid valve 106 is on, the third external piping 103c and the bypass flow path 105 (the seventh external piping 103g) are connected such that the refrigerant discharged from the cooling pump 102 is directly supplied to the high-voltage equipment cooling unit 120 (the DC-DC converter cooling unit 122 and the charger cooling unit 121), while the third external piping 103c is disconnected from the fourth external piping 103d such that the supply of the refrigerant to the battery cooling unit 130 is cut off. Incidentally, in FIG. 4, arrows denote flows of the refrigerant, and there is no such situation where both the fourth external piping 103d and the bypass flow path 105 (the seventh external piping 103g) are connected to the third external piping 103c.

(39) As shown in FIG. 4, among the external pipings 103 disposed outside the first battery unit 10 and the second battery unit 60, the fourth external piping 103d, the fifth external piping 103e, the sixth external piping 103f, and the seventh external piping 103g are disposed at one vehicle width side of the first battery unit 10 (in FIG. 4, a left side in the vehicle width direction). In other words, the external pipings 103 are not provided at another vehicle width side of the first battery unit 10 (in FIG. 4, a right side in the vehicle width direction). For example, in the hybrid vehicle or the like, an exhaust pipe extending from an engine disposed in the engine room 7 at the front of the vehicle to the rear of the vehicle is preferably arranged at the other vehicle width side of the first battery unit 10 (in FIG. 4, the right side in the vehicle width direction). Therefore, the external pipings 103 in the cooling circuit 100 can be prevented from being heated up by heat caused by the exhaust pipe.

(40) FIG. 5 is a schematic block diagram of the cooling circuit 100 which is described in detail by using FIG. 4, In FIG. 5, CHG denotes the charger cooling unit 121, DCDC denotes the DC-DC converter cooling unit 122, and BATT denote the module group cooling units 131 to 133 (the same in FIGS. 6 to 9 described below).

(41) As shown in FIG. 5, in the cooling circuit 100 of this embodiment, the radiator 101, the cooling pump 102, the battery cooling unit 130, and the high-voltage equipment cooling unit 120 configured by the charger cooling unit 121 and the DC-DC cooling unit 122 are connected in series, and the high-voltage equipment cooling unit 120 is disposed at the downstream side of the battery cooling unit 130. In addition, the upstream side of the battery cooling unit 130 is connected to the upstream side of the high-voltage equipment cooling unit 120 and the downstream side of the battery cooling unit 130 by the bypass flow path 105, and the three-way solenoid valve 106 is provided at the branch portion 114 where the bypass flow path 105 branches off from an upstream-side flow path of the battery cooling unit 130. Further, the battery cooling unit 130 includes the three module group cooling units 131 to 133 which are connected in series, and the high-voltage equipment cooling unit 120 includes the DC-DC converter cooling unit 122 and the charger cooling unit 121 which are connected in series.

(42) [Operation of Cooling Circuit]

(43) Next, the operation of the cooling circuit 100 will be described mainly by reference to FIGS. 6 and 7. In FIGS. 6 and 7, the flow paths through which the refrigerant flows are denoted by solid lines, whereas the flow paths through which no refrigerant flows are denoted by broken lines.

(44) <Three-Way Solenoid Valve [OFF]>

(45) In the above-described cooling circuit 100, when the cooling pump 102 is driven, the cooling pump 102 suctions the refrigerant of which a temperature is lower from the radiator 101 side and discharges the refrigerant towards the battery cooling unit 130. In a normal state, since the three-way solenoid valve 106 is off, as shown in FIG. 6, the refrigerant discharged from the cooling pump 102 does not flow to the bypass flow path 105 and is supplied to the battery cooling unit 130.

(46) The refrigerant supplied to the battery cooling unit 130 flows to the rear module group cooling unit 133, the middle module group cooling unit 132, and the front module group cooling unit 131 in this order. As described above in FIG. 4, in the module group cooling units 131 to 133, the cooling jackets 131a to 133a are connected in parallel respectively. That is, since the plurality of cooling jackets 131a are connected in parallel in the front module group cooling unit 131, the refrigerant supplied to the front module group cooling unit 131 is distributed to each cooling jacket 131a at the inlet port 131b of the front module group cooling unit 131, and flows of the refrigerant merge, together at the outlet port 131c after passing through each cooling jacket 131a. Similarly, the refrigerant supplied to the middle module group cooling unit 132 is distributed to each cooling jacket 132a at the inlet port 132b of the middle module group cooling unit 132, and flows of the refrigerant merge together in the outlet port 132c after passing through each cooling jacket 132a. The refrigerant supplied to the rear module group cooling unit 133 is distributed to each cooling jacket 133a at the inlet port 133b of the rear module group cooling unit 133, and flows of the refrigerant merge together in the outlet port 133c after passing through each cooling jacket 133a.

(47) Returning to FIG. 6, the refrigerant having passed through the three module group cooling units 131 to 133 flows to the DC-DC converter cooling unit 122 and the charger cooling unit 121 in this order, and returns to the radiator 101 where the refrigerant is cooled.

(48) <Three-Way Solenoid Valve [ON]>

(49) In the cooling circuit 100, when the battery 30 does not need to be cooled or when the DC-DC converter 22 acid the charger 21 need to be cooled although the temperature of the refrigerant is not suitable for the required temperature of the battery 30, the three-way solenoid valve 106 is controlled to be on, so that as shown in FIG. 7, the supply of the refrigerant to the battery cooling unit 130 is cut off, and only the DC-DC converter 22 and the charger 21 can be cooled. That is, when the three-way, solenoid valve 106 is on, the refrigerant discharged from the cooling pump 102 does not flow to the battery cooling unit 130 and is supplied to the bypass flow path 105. After the refrigerant supplied to the bypass flow path 105 bypasses the battery cooling unit 130 and flows to the DC-DC converter cooling unit 122 and the charger cooling unit 121 in this order, the refrigerant returns to the radiator 101 where the refrigerant is cooled.

(50) [Summary]

(51) As has been described above, according to the vehicle power source system 1 of this embodiment, since the module group cooling unit 131 (132, 133) includes the plurality of cooling jackets 131a (132a, 133a), the cooling efficiency is higher compared with a case where one cooling jacket is arranged at the center of the module group 31 (32, 33). In addition, since the cooling jackets 131a (132a, 133a) are connected in parallel, the pressure loss can be reduced compared with a case where the cooling jackets 131a (132a, 133a) are connected in series, and further the temperature variation can be reduced in the module group cooling unit 131 (132, 133). Further, the module group cooling units 131, 132, and 133 in which the cooling jackets 131a, 132a, and 133a are connected in parallel are connected in series, so that freedom of the vehicle mountability is improved, while the temperature variation can be reduced in the module group cooling units 131, 132, and 133 and the cooling efficiency of the cooling circuit 100 can be enhanced.

(52) Since the high-voltage equipment cooling unit 120 is disposed at the downstream side of the battery cooling unit 130 (module group cooling units 131 to 133), the battery 30 with low control temperature (poor heat resistance) can be reliably cooled without being affected by the temperature of the high-voltage equipment 20 even when both the battery 30 and the high-voltage equipment 20 are cooled.

(53) The battery cooling unit 130 (module group cooling units 131, 132, and 133) is bypassed by the bypass flow path 105, which connects the upstream side of the battery cooling unit 130 (module group cooling units 131, 132, and 133) to the upstream side of the high-voltage equipment cooling unit 120 and the downstream side of the battery cooling unit 130 (module group cooling units 131, 132, and 133), so that it is possible to only cool the high-voltage equipment 20 as necessary.

(54) Based on the flow path switching control corresponding to states of the battery 30, the temperature of the battery 30 can be controlled appropriately by the three-way solenoid valve 106 which is provided at the upstream side of the battery cooling unit 130 (module group cooling units 131, 132, and 133).

(55) Since the DC-DC converter cooling unit 122 and the charger cooling unit 121 are connected in series in this order from the upstream side thereof, a flow rate necessary for the charger 21 and the DC-DC converter 22 can be ensured. Further, the DC-DC converter cooling unit 122 for cooling the DC-DC converter having the smaller heat value is disposed at the upstream side of the charger cooling unit 121 for cooling the charger 21 having the greater heat value, so that the cooling efficiency can be enhanced.

(56) By dividing battery 30 into the front module group 31, the middle module group 32, and the rear module group 33, which are arranged in the front-rear direction of the vehicle, weight balance in the front-rear direction of the vehicle can be distributed properly.

(57) Since the module groups 31 to 33 and the module group cooling units 131, 132, and 133 are disposed below the floor panel 3, a wide space in the passenger compartment can be ensured. Further, since the cooling circuit 100 is independent of the passenger compartment 2, the design suitable for respective function can be made.

(58) The module groups 31 to 33 configuring different battery units 10 and 60 can be cooled by the same cooling circuit 100 although the first battery unit 10 including the front module group 31 and the middle module group 32 and the second battery unit 60 including the rear module group 33 are independently fixed to the floor frame, and therefore, the number of components and manufacturing cost can be reduced.

(59) Since the DC-DC converter 22 is disposed inside the first battery unit 10, the front module group cooling unit 131, the middle module group cooling unit 132, and the DC-DC converter cooling unit 122 can be aggregated inside the first battery unit 10. Since a waterproof measure is provided in the first battery unit 10, a waterproof function of the DC-DC converter 22 can be improved by a waterproof function of the first battery unit 10 in addition to the waterproof function of the DC-DC converter 22.

(60) Since the fourth external piping 103d, the fifth external piping 103e, the sixth external piping 103f, and the seventh external piping 103g are only disposed at the one vehicle width side of the first battery unit 10, the pipings can be assembled easily.

(61) The DC-DC converter 22, and the high-voltage wiring (not shown) for connecting the front module group 31 and the middle module group 32 to the DC-DC converter 22 are disposed at the vehicle width center of the first battery unit 10, so that the DC-DC converter 22 and high-voltage wiring can be protected from an impact at a side collision. Since the DC-DC converter 22 and high-voltage wiring are away from the fourth external piping 103d, the fifth external piping 103e, the sixth external piping 103f, and the seventh external piping 103g, the DC-DC converter 22 and high-voltage wiring can also be protected from being wet.

(62) Since the rear module group cooling unit 133, the middle module group cooling unit 132, and the front module group cooling unit 131 are connected in series in this order from the upstream side thereof, the cooling circuit 100 can be simply configured by allowing the refrigerant flow from the rear of the vehicle to the front of the vehicle.

(63) [Modification]

(64) The present invention is not limited to the embodiment described above and can be modified or improved as required.

(65) For example, in the above-described embodiment, the battery 30 is divided into the front module group 31, the middle module group 32, and the rear module group 33, the front module group 31 and the middle module group 32 are disposed in the first battery unit 10, the rear module group 33 is disposed in the second battery unit 60, and the module groups 31 to 33 are all cooled by the cooling circuit 100. However, other cooling circuits may be provided for the battery units 10 and 60, respectively.

(66) In the interior cooling circuit 100A of the first battery unit 10, the cooling jackets 131a and 132a of the module group cooling units 131 and 132 are connected in parallel, and the module group cooling unit 131 and the module group cooling unit 132 may be connected in series. FIG. 8 is a vehicle power source system according to a modification, wherein an interior cooling circuit 100B of a second battery unit 60 is different from that of the vehicle power source system in the above-described embodiment.

(67) In the interior cooling circuit 100B of the modification, a rear module group cooling unit 133 for cooling the rear module group 33 includes a plurality of down-stage module cooling units 133d for respectively cooling a plurality of battery modules 30a located at a lower stage (hereinafter, the battery module 30a located at the lower stage is referred to as a battery module 30ad), and a plurality of upper-stage module cooling units 133u for respectively cooling a plurality of battery modules 30a located at an upper stage (hereinafter, the battery module 30a located at the upper stage is referred to as a battery module 30au). The down-stage module cooling unit 133d includes four cooling jackets 133a for respectively cooling the battery modules 30a at the first stage, and the higher-stage module cooling unit 133u includes four cooling jackets 133a for respectively cooling the battery modules 30a at the second stage.

(68) In the above-described embodiment, the cooling jackets 133a of the down-stage module cooling unit 133d are connected in parallel, the cooling jackets 133a of the upper-stage module cooling unit 133u are connected in parallel, and the down-stage module cooling unit 133d and the upper-stage module cooling units 133u are connected in parallel. However, in the modification, the cooling jackets 133a of the down-stage module cooling units 133d are connected in parallel, the cooling jackets 133a of the upper-stage module cooling units 133u are connected in parallel, and the down-stage module cooling units 133d and the upper-stage module cooling units 133u are connected in series.

(69) According to the modification, in the interior cooling circuit 100B, the plurality of down-stage module cooling units 133d which are connected in parallel and the plurality of upper-stage module cooling units 133u which are connected in parallel are connected in series, so that pressure loss can be reduced while a flow rate can be suppressed.

(70) In the above-described embodiment, examples of the high-voltage equipment include the DC-DC converter 22 and the charger 21. However, the high-voltage equipment may include any one of the DC-DC converter 22 and the charger 21, or other high-voltage equipment such as an inverter, or a plurality of the above equipment may be included.

(71) Further, the cooling circuit 100 of the above-described embodiment may be a water-cooled cooling circuit which utilizes water as a refrigerant or an oil-cooled cooling circuit which utilizes oil as a refrigerant.