On-board battery for a vehicle

Abstract

On-board battery (1) for a vehicle, with: battery modules (3), each comprising battery cells (11) arranged therein; a receiving housing (2) that accommodates the battery modules (3); and at least one inlet channel (19, 30) through which cooling air is supplied to the battery modules (3), wherein the cooling air is supplied to the battery modules (3) from the rear via the at least one inlet channel (19, 30), wherein the onboard battery (1) comprises at least four battery modules (3D, 3E, 3B, 3C), wherein at least two of the battery modules (3) are arranged in an upper and a lower plane, wherein at least two of the battery modules (3D, 3E, 3B, 3C) are arranged along a longitudinal direction, wherein the onboard battery (1) further comprises a battery module (3A) which is arranged at a front, wherein the at least two battery modules (3D, 3E, 3B, 3C) arranged in the upper and lower planes are arranged behind the battery module (3A) arranged at the front, and wherein one of the battery modules (3A) which is located at the front is arranged in a middle plane with respect to the at least two battery modules which are arranged in the upper and lower planes.

Description

Cross-reference to related applications

[0001] The present application claims priority to JP 2016 - 134243 A filed on January 16, 2015, the entire contents of which are incorporated herein by reference Background of the invention 1. Technical field

[0002] The present invention relates to the technical field of on-board batteries installed in vehicles such as automobiles and usable even in cold areas. 2. State of the art

[0003] On-board batteries are installed in various vehicles, such as automobiles, to supply electrical energy to electric motors and various other electrical components.

[0004] In recent years, vehicles such as electric vehicles (EVs), hybrid electric vehicles (HEVs), and plug-in hybrid electric vehicles (PHEVs) have become particularly widespread. These electrically powered vehicles feature on-board batteries with high electrical energy storage capacity.

[0005] An on-board battery comprises a housing and a battery module housed in the housing. The battery module is configured, for example, by arranging multiple battery cells (secondary batteries), such as nickel-hydrogen batteries or lithium-ion batteries. In an on-board battery to be installed in an electric vehicle or the like, to achieve high electrical energy storage capacity, multiple battery modules are arranged in the housing, and battery cells of each of the battery modules are connected in series or parallel.

[0006] An example of an on-board battery is a type in which the battery modules are arranged in two levels, an upper and a lower level, within the housing as a structure for providing high electrical energy storage capacity (see JP 5 206 110 B2). Other on-board batteries are described in US 2013 / 0122338 A1, US 2012 / 0031695 A1, US 2013 / 0298586 A1, and US 2013 / 0330587 A1.

[0007] The on-board battery shown in JP 5 206 110 B2 is arranged in a rear trunk, with the lower level battery module being inserted into a recessed section with an upper opening in a floor panel, thus ensuring a large volume for the trunk.

[0008] It should be noted that a battery cell generates heat during operation, so the temperature rise caused by this heat must be suppressed by cooling the battery cell in order to ensure favorable performance of the battery cell and various other control devices arranged in the housing. The above-described on-board battery, in which multiple battery modules are arranged, generates a particularly large amount of heat. Therefore, it is desirable to increase the cooling efficiency of the multiple battery modules. Brief description of the invention

[0009] Therefore, it is an object of the present invention to increase the cooling efficiency of the battery cells in order to suppress a temperature rise caused by the heat generated by the battery cells.

[0010] According to one aspect of the present invention, an on-board battery for a vehicle is an on-board battery comprising: battery modules each having battery cells arranged therein, a receiving housing that accommodates the battery modules, and at least one inlet duct through which cooling air is supplied to the battery modules. The cooling air is supplied to the battery modules from the rear via the inlet duct. The on-board battery has at least four battery modules, wherein at least two of the battery modules are arranged in an upper and a lower plane. At least two of the battery modules are arranged along a longitudinal direction. Furthermore, one battery module is arranged at a front side.

[0011] The battery module arranged at the front may be arranged in a middle plane with respect to the two battery modules arranged in the upper and lower planes.

[0012] The on-board battery may include a fan connected to the at least one intake duct. The fan may be arranged on the left and / or right side of a rear end portion of the housing.

[0013] The inlet duct may include a first inlet duct and a second inlet duct. The first inlet duct may cause the cooling air to be supplied to at least one of the battery modules, and the second inlet duct may cause the cooling air to be supplied to at least one other of the battery modules.

[0014] The cooling air supplied via the first inlet duct and having cooled the at least one battery module can be discharged from the at least one battery module to the inside of the receiving case, and the cooling air supplied via the second inlet duct and having cooled the at least one other battery module can be discharged from the at least one other battery module to the inside of the receiving case. The cooling air supplied via the first inlet duct and the cooling air supplied via the second inlet duct can be discharged from positions spaced apart from each other in the transverse direction.

[0015] The inlet duct may have inflow sections, via which the cooling air is supplied to a corresponding one of the battery modules, and an alignment fin may be arranged in the inflow section, via which the cooling air is supplied to the rearmost battery module.

[0016] The battery cells may be arranged uniformly, and the battery modules may be arranged inside the receiving housing such that the battery cells are arranged along a transverse direction. Short description of the drawings Fig. Figure 1 shows a perspective view of an embodiment of an on-board battery according to the invention in conjunction with the Fig. 2 to 14; Fig. 2 shows a perspective view of the on-board battery with a part thereof omitted; Fig. 3 is a schematic diagram showing a state or the like of the arrangement of the battery modules in the on-board battery; Fig. 4 shows a schematic perspective view of a battery module and a distribution channel in a disassembled state; Fig. 5 shows a perspective view of a first inlet unit; Fig. 6 shows a perspective view of a second inlet unit; Fig. 7 is an enlarged cross-sectional view showing a state in which alignment blades are arranged; Fig. 8 shows battery modules and distribution channels in connection with the Fig. 9 to 12, and shows a perspective view of a first battery module and a first distribution channel; Fig. 9 shows a perspective view of a second battery module and a second distribution channel; Fig. 10 shows a perspective view of a third battery module and a third distribution channel; Fig. 11 shows a perspective view of a fourth battery module and a fourth distribution channel; Fig. 12 shows a perspective view of a fifth battery module and a fifth distribution channel; Fig. 13 shows a graph for illustrating a relationship or the like between a battery cell and temperature; and Fig. 14 shows a schematic rear view of part of a second inlet channel. Detailed description

[0017] A preferred embodiment of the present invention will be described in more detail below with reference to the accompanying drawings. It should be noted that in this description and the accompanying drawings, structural elements having substantially the same function and structure are denoted by the same reference numerals and will not be described repeatedly.

[0018] An embodiment of an on-board battery according to the invention will be described below with reference to the accompanying drawings.

[0019] An on-board battery 1 has a housing 2 and battery modules 3 (cf. Fig. 1 to 3). The on-board battery 1 is arranged, for example, in a trunk of a vehicle.

[0020] The receiving housing 2 has a receiving housing part 4 and a cover part 5, wherein the receiving housing part 4 has an upper opening and the cover part 5 has the shape of a plate in order to close the opening of the receiving housing part 4 from above.

[0021] The receiving housing part 4 has a front wall 6, a rear wall 7, two side walls 8, and a bottom wall 9. The front wall 6 faces the longitudinal direction, the rear wall 7 is arranged behind the front wall 6 and faces the longitudinal direction, the side walls 8 are arranged spaced apart from each other in the transverse direction, and the bottom wall 9 faces the vertical direction. Each wall below the front wall 6, the rear wall 7, the side walls 8, and the bottom wall 9 is formed, for example, by extruding aluminum and has a hollow cross-section.

[0022] For example, although not shown, a plurality of cavities extending from one side to the other side and arranged in the vertical direction are formed in the front wall 6 and the rear wall 7, a plurality of cavities extending in the longitudinal direction and arranged in the vertical direction are formed in each of the side walls 8, and a plurality of cavities extending from one side to the other side and arranged in the longitudinal direction are formed in the bottom wall 9.

[0023] Almost the entire upper half of the front wall 6 is an inclined portion 6a which is inclined rearward in the upward direction.

[0024] The bottom wall 9 has a front end portion as an upper platform portion 9a, which is arranged one level higher than other portions of the bottom wall 9 (cf. Fig. 3). The bottom wall 9 has a rear portion as a lower platform portion 9c, and a bridge portion disposed between the upper platform portion 9a and the lower platform portion 9c is a platform connecting portion 9b facing substantially the longitudinal direction.

[0025] For example, five battery modules 3 are arranged in the longitudinal and vertical directions and accommodated in the receiving case 2. The battery modules 3 include a first battery module 3A arranged at the front, a second battery module 3B arranged behind the first battery module 3A, a third battery module 3C arranged behind the second battery module 3B, a fourth battery module 3D arranged behind the first battery module 3A and directly above the second battery module 3B, and a fifth battery module 3E arranged behind the fourth battery module 3D and directly above the third battery module 3C.

[0026] The first battery module 3A, the second battery module 3B, the third battery module 3C, the fourth battery module 3D and the fifth battery module 3E are connected in series by electrical wiring.

[0027] Each of the battery modules 3 has a housing body 10 and a plurality of battery cells 11 accommodated within the housing body 10 (cf. Fig. 4).

[0028] The housing body 10 is shaped like a rectangular box with a top and a rear opening. The housing body 10 has a wide front surface part 12, two side surface parts 13, and a wide bottom surface part 14. The front surface part 12 faces the longitudinal direction, the side surface parts 13 face the transverse direction and are spaced apart from each other in the transverse direction, and the bottom surface part 14 faces the vertical direction. The interior of the housing body 10 serves as a receiving space.

[0029] The front surface part 12 has an outlet hole 12a extending longitudinally through the front surface part 12 at any one of a right end portion, a left end portion, and a center portion in the transverse direction. Specifically, the first battery module 3A has the outlet hole 12a at the right end portion of the front surface part 12, the second battery module 3B has the outlet hole 12a at the left end portion of the front surface part 12, the third battery module 3C has the outlet hole 12a at the center portion of the front surface part 12 in the transverse direction, the fourth battery module 3D has the outlet hole 12a at the right end portion of the front surface part 12, and the fifth battery module 3E has the outlet hole 12a at the center portion of the front surface part 12 in the transverse direction. Fig. 4 shows an example in which the outlet hole 12a is formed at the right end portion of the front surface part 12.

[0030] The battery cells 11 are arranged, for example, from one side to the other at regular intervals such that the thickness direction of the battery cells corresponds to the transverse direction, and are arranged in the receiving space such that they are held in the case body 10. For example, 19 battery cells 11 are held in the case body 10. In the state in which the battery cells 11 are held in the case body 10, constant gaps are formed between each of the adjacent battery cells 11. Furthermore, the battery cells 11 are connected in series.

[0031] As described above, the battery modules 3 of the on-board battery 1 are arranged within the receiving case 2 such that the battery cells 11 are arranged along the transverse direction.

[0032] Therefore, the battery modules 3 become wider and the length of the on-board battery 1 is shortened in the longitudinal direction; moreover, the housing 2 can accommodate a larger number of battery cells 11. This allows the on-board battery 1 to be downsized while simultaneously increasing its performance.

[0033] The housing body 10 has a gas outlet pipe 15 extending in the transverse direction. The gas outlet pipe 15 has a base plate portion 15a facing the vertical direction and a tubular portion 15b arranged on top of the base plate portion 15a. The tubular portion 15b is arranged at a central portion of the base plate portion 15a in the longitudinal direction. The gas outlet pipe 15 is fixed to the housing body 10 such that the base plate portion 15a closes the upper opening of the housing body 10.

[0034] Although not shown, gas flow holes are arranged at regular intervals from side to side on the underside of the gas outlet pipe 15. The gas flow holes of the gas outlet pipe 15 are arranged directly above the respective battery cells 11.

[0035] Two wide plates 16 are fixed to both end portions of the base plate portion 15a of the gas outlet pipe 15 in the longitudinal direction. Each of the plates 16 is connected to an electrical wiring described later, so that the battery cells 11 can be electrically controlled via, for example, the electrical wiring and the plates 16.

[0036] Although not shown, each of the battery cells 11 has a valve capable of establishing a communicating state. Each valve communicates with a corresponding gas flow hole of the gas outlet pipe 15. In the event of a malfunction, gas may be generated inside a battery cell 11. However, the generation of gas increases the internal pressure of the battery cell 11, causing the valve to open, and the generated gas to flow to the gas outlet pipe 15 via the valve and the gas flow hole.

[0037] Although not shown, each of the battery modules 3 is mounted on the receiving case 2 by a mounting plate and arranged at a predetermined position (see FIG. Fig. 3). The second battery module 3B and the third battery module 3C are arranged in the lower layer, the fourth battery module 3D and the fifth battery module 3E are arranged in the upper layer, and the first battery module 3A is arranged in a middle layer with respect to the second battery module 3B, the third battery module 3C, the fourth battery module 3D, and the fifth battery module 3E. Note that the first battery module 3A may be arranged in the lower layer together with the second battery module 3B and the third battery module 3C, or the first battery module may be arranged in the upper layer together with the fourth battery module 3D and the fifth battery module 3E.

[0038] During operation of the battery modules 3, cooling air is introduced into the battery modules 3 from a first inlet unit 17 and a second inlet unit 18 (cf. Fig. 1, Fig. 3, Fig. 5 and Fig. 6).

[0039] The first inlet unit 17 has a first inlet channel 19, a first intake fan 20, a first intake pipe 21 and three distribution channels 22 (cf. Fig. 1 and Fig. 5).

[0040] The cooling air is supplied to the first battery module 3A, the second battery module 3B, and the third battery module 3C via the first inlet channel 19. The first inlet channel 19 has an inlet section 23, an intermediate section 24, a first inflow section 25, a second inflow section 26, and a third inflow section 27.

[0041] The inlet section 23 is located on the right side and is substantially V-shaped. Approximately half of the inlet section 23 extends substantially in the vertical direction, and the other half extends substantially in the transverse direction. The intermediate section 24 extends in the transverse direction, and a right end portion thereof further extends to a left end portion of the inlet section 23.

[0042] A front end portion of the first inflow portion 25 is bent upward with respect to other portions of the first inflow portion 25 extending in the longitudinal direction. Furthermore, a rear end portion of the first inflow portion 25 further extends to a left end portion of the intermediate portion 24. A front end portion of the second inflow portion 26 is bent upward with respect to other portions of the second inflow portion 26 extending in the longitudinal direction. Furthermore, a rear end portion of the second inflow portion 26 further extends to the right end portion of the intermediate portion 24. The third inflow portion 27 extends in the longitudinal direction, and a rear end portion of the third inflow portion 27 further extends to a substantially central portion of the intermediate portion 24 in the transverse direction.The lengths of the first inflow section 25, the second inflow section 26 and the third inflow section 27 in the longitudinal direction decrease in this order.

[0043] The first intake fan 20 is connected to an upper end portion of the inlet portion 23.

[0044] A lower end portion of the first intake pipe 21 is connected to the first intake fan 20. Therefore, when the first intake fan 20 rotates, the cooling air is sucked in by the first intake pipe 21 and flows toward the first intake duct 19.

[0045] The distribution channels 22 consist of a first distribution channel 22A, a second distribution channel 22B, and a third distribution channel 22C. Cooling air is supplied to the first battery module 3A via the first distribution channel 22A, cooling air is supplied to the second battery module 3B via the second distribution channel 22B, and cooling air is supplied to the third battery module 3C via the third distribution channel 22C. The first distribution channel 22A, the second distribution channel 22B, and the third distribution channel 22C are arranged in this order from front to rear.

[0046] Each of the distribution channels 22 includes a main body portion 28 and a connecting portion 29. The main body portion 28 has a wide, substantially rectangular shape, and the connecting portion 29 protrudes from the main body portion 28. The distribution channel 22 has a cavity. The main body portion 28 includes outlet projections 28a that protrude forward and are spaced at regular intervals in the transverse direction. Each of the outlet projections 28a has an opening at the end.

[0047] The connecting portion 29 of the first distribution channel 22A projects downward from a left end portion of the main body portion 28, the connecting portion 29 of the second distribution channel 22B projects downward from a right end portion of the main body portion 28, and the connecting portion 29 of the third distribution channel 22C projects rearward from a central portion of the main body portion 28 in the transverse direction.

[0048] The second inlet unit 18 has a second inlet channel 30, a second intake fan 31, a second intake pipe 32 and two distribution channels 22 (cf. Fig. 1 and Fig. 6).

[0049] The cooling air is supplied to the fourth battery module 3D and the fifth battery module 3E via the second inlet duct 30. The second inlet duct 30 has an inlet section 33, an intermediate section 34, a fourth inflow section 35, and a fifth inflow section 36.

[0050] The inlet section 33 is located on the left side and has a substantially V-shape. Approximately half of the inlet section 33 extends substantially in the vertical direction, and the other half extends substantially in the transverse direction. The intermediate section 34 extends in the transverse direction, and a left end portion thereof further extends to a right end portion of the inlet section 33.

[0051] A front end portion of the fourth inflow portion 35 is bent to the right with respect to other portions of the fourth inflow portion 35 extending in the longitudinal direction. Furthermore, a rear end portion of the fourth inflow portion 35 further extends to the left end portion of the intermediate portion 34. The fifth inflow portion 36 extends in the longitudinal direction, and a rear end portion of the fifth inflow portion 36 further extends to a right end portion of the intermediate portion 34. The length of the fourth inflow portion 35 is greater than the length of the fifth inflow portion 36 in the longitudinal direction.

[0052] The second intake fan 31 is connected to an upper end portion of the inlet portion 33.

[0053] A lower end portion of the second intake pipe 32 is connected to the second intake fan 31. Therefore, when the second intake fan 31 rotates, the cooling air is sucked in from the second intake pipe 32 and flows toward the second intake duct 30.

[0054] The distribution channels 22 consist of a fourth distribution channel 22D and a fifth distribution channel 22E. The fourth distribution channel 22D supplies the cooling air to the fourth battery module 3D, and the fifth distribution channel 22E supplies the cooling air to the fifth battery module 3E. The fourth distribution channel 22D is arranged in front of the fifth distribution channel 22E.

[0055] A connecting portion 29 of the fourth distribution channel 22D protrudes leftward from a left end portion of the main body portion 28 of the fourth distribution channel 22D, and a connecting portion 29 of the fifth distribution channel 22E protrudes rearward from a central portion of a main body portion 28 of the fifth distribution channel 22E in the transverse direction.

[0056] Three alignment fins 37 are arranged inside the connecting portion 29 of the third distribution channel 22C, which is arranged closest to the first inlet unit 17, and inside the connecting portion 29 of the fifth distribution channel 22E, which is arranged closest to the second inlet unit 18 (cf. Fig. 7). The alignment blades 37 are arranged spaced apart from each other in the transverse direction. The center alignment blade 37 faces the transverse direction, the left alignment blade 37 is arranged at an inclination such that its front end is farther away from the center alignment blade 37, and the right alignment blade 37 is arranged at an inclination such that its front end is farther away from the center alignment blade 37.

[0057] As in Fig. 1, the first intake unit 17 is arranged with respect to the receiving case 2 such that the first intake fan 20 is arranged on the right side of a rear end portion of the receiving case 2, and the intermediate portion 24 of the first intake duct 19 is arranged to face the rear wall 7 of the receiving case 2.

[0058] In the state where the first inlet unit 17 is arranged with respect to the accommodating case 2, the rear end portion of the first inflow portion 25 extends through the rear wall 7, and the main body portion 28 of the first distribution channel 22A is arranged to face the rear surfaces of the battery cells 11 of the first battery module 3A (see FIG. Fig. 8). The first inflow section 25 is arranged below the second battery module 3B and the third battery module 3C within the receiving housing 2.

[0059] The rear end portion of the first inflow portion 25 is connected to the rear wall 7 in such a way that it protrudes rearwardly from the rear wall 7 (cf. Fig. 2). The opening in the rear of the first inflow section 25 serves as a first air inlet hole 38 for supplying the cooling air to the first battery module 3A.

[0060] In the state in which the first inlet unit 17 is arranged with respect to the receiving housing 2, the rear end portion of the second inflow portion 26 extends through the rear wall 7 (cf. Fig. 1) and the main body portion 28 of the second distribution channel 22B is arranged such that it faces the rear surfaces of the battery cells 11 of the second battery module 3B (cf. Fig. 9). The second inflow section 26 is arranged below the third battery module 3C inside the receiving housing 2.

[0061] The rear end portion of the second inflow portion 26 is connected to the rear wall 7 in such a way that it projects rearwardly from the rear wall 7 (cf. Fig. 2). The opening at the rear of the second inflow section 26 serves as a second air inlet hole 39 for supplying cooling air to the second battery module 3B.

[0062] In the state in which the first inlet unit 17 is arranged with respect to the receiving housing 2, the third inflow section 27 extends through the rear wall 7 (cf. Fig. 1) and the main body portion 28 of the third distribution channel 22C is arranged such that it faces the rear surfaces of the battery cells 11 of the third battery module 3C (cf. Fig. 10).

[0063] The third inflow section 27 is connected to the rear wall 7 in such a way that it protrudes rearward from the rear wall 7 (cf. Fig. 2). The opening at the rear of the third inflow section 27 serves as a third air inlet hole 40 for supplying cooling air to the third battery module 3C.

[0064] As in Fig. 1, the second intake unit 18 is arranged with respect to the accommodation case 2 such that the second intake fan 31 is located on the left side of the rear end portion of the accommodation case 2, and the intermediate portion 34 of the second intake duct 30 is arranged to face the rear side of the rear wall 7 of the accommodation case 2. The intermediate portion 34 is located above the intermediate portion 24 of the first intake unit 17. Therefore, the intermediate portion 24 and the intermediate portion 34 do not overlap in the longitudinal direction, so that the on-board battery 1 can be downsized in the longitudinal direction.

[0065] In the state in which the second inlet unit 18 is arranged with respect to the receiving housing 2, the rear end portion of the fourth inflow portion 35 extends through the rear wall 7 (see Fig. 1) and the main body portion 28 of the fourth distribution channel 22D is arranged to face the rear surfaces of the battery cells 11 of the fourth battery module 3D (cf. Fig. 11). The fourth inflow section 35 is arranged on the left side of the fifth battery module 3E within the receiving housing 2.

[0066] The rear end portion of the fourth inflow portion 35 is connected to the rear wall 7 in such a way that it protrudes rearward from the rear wall 7 (cf. Fig. 2). The opening at the rear of the fourth inflow portion 35 serves as a fourth air inlet hole 41 for supplying the cooling air to the fourth battery module 3D.

[0067] In the state in which the second inlet unit 18 is arranged with respect to the receiving housing 2, the fifth inflow section 36 extends through the rear wall 7 (cf. Fig. 1) and the main body portion 28 of the fifth distribution channel 22E is arranged such that it faces the rear surfaces of the battery cells 11 of the fifth battery module 3E (cf. Fig. 12).

[0068] The fifth inflow section 36 is connected to the rear wall 7 in such a way that it protrudes rearwardly from the rear wall 7 (cf. Fig. 2). The opening at the rear of the fifth inflow section 36 serves as a fifth air inlet hole 42 for supplying the cooling air to the fifth battery module 3E.

[0069] As described above, the distribution channels 22 are arranged such that the respective main body sections 28 face the rear surfaces of the battery cells 11 (cf. Fig. 8 to 12). In this case, one of the outlet projections 28a of the main body section 28 is arranged between the battery cells 11 (cf. Fig. 7). Therefore, the cooling air discharged from each of the outlet projections 28a flows forward through gaps formed between the battery cells 11.

[0070] A flow path of the cooling air is described below.

[0071] When the first intake fan 20 and the second intake fan 31 rotate, air outside the receiving housing 2 is sucked into the first inlet duct 19 and the second inlet duct 30 as cooling air via the first intake pipe 21 and the second intake pipe 32, respectively.

[0072] The cooling air drawn into the first intake duct 19 flows from the intake unit 23 to the intermediate section 24 and is distributed into the first inflow section 25, the second inflow section 26, and the third inflow section 27. The divided cooling air flows toward the first distribution duct 22A, the second distribution duct 22B, and the third distribution duct 22C and is discharged to the first battery module 3A, the second battery module 3B, and the third battery module 3C, respectively.

[0073] Because the alignment fins 37 are arranged in the connecting portion 29 of the third distribution channel 22C, which is closest to the first inlet unit 17, the alignment fins 37 cause a pressure loss.

[0074] Therefore, the cooling air that has flowed to the intermediate section 24 will also easily flow into the first inflow section 25 and the second inflow section 26. Therefore, the flow rates of the cooling air supplied to the first battery module 3A, the second battery module 3B, and the third battery module 3C are averaged, resulting in an increase in cooling efficiency.

[0075] The alignment blades 37 are arranged as follows: the left alignment blade 37 has an inclination such that its front end is further spaced from the middle alignment blade 37, and the right alignment blade 37 has an inclination such that its front end is further spaced from the middle alignment blade 37.

[0076] Therefore, the cooling air supplied from a central portion of the third distribution duct 22C in the transverse direction flows slightly to the left and right, and uniform cooling air is easily supplied to the third battery module 3C in the transverse direction, thereby increasing the cooling efficiency of the battery cells 11 of the third battery module 3C.

[0077] The cooling air supplied to the first battery module 3A, the second battery module 3B, and the third battery module 3C flows forward through the spaces between the battery cells 11, thereby cooling the battery cells 11. The cooling air flowing forward through the spaces between the battery cells 11 is discharged from the outlet hole 12a of the front surface part 12 into the interior of the receiving case 2.

[0078] On the other hand, the cooling air drawn into the second intake passage 30 flows from the intake section 33 to the intermediate section 34 and is distributed to the fourth inflow section 35 and the fifth inflow section 36. The divided cooling air flows toward the fourth distribution passage 22D and the fifth distribution passage 22E to be supplied to the fourth battery module 3D and the fifth battery module 3E, respectively.

[0079] Because three alignment fins 37 are arranged in the connecting portion 29 of the fifth distribution channel 22E arranged behind the second inlet unit 18, the alignment fins 37 cause a pressure loss.

[0080] Therefore, the cooling air that has flowed to the intermediate section 34 will also easily flow into the fourth inflow section 35 and the fifth inflow section 36. Therefore, the flow rates of the cooling air flowing into the fourth battery module 3D and the fifth battery module 3E are averaged, thereby increasing the cooling efficiency.

[0081] The alignment blades 37 are arranged as follows: the left alignment blade 37 has an inclination such that its front end is further away from the middle alignment blade 37, and the right alignment blade 37 has an inclination such that its front end is further away from the middle alignment blade 37.

[0082] Therefore, the cooling air supplied from a central portion of the fifth distribution duct 22E in the transverse direction flows slightly to the left and right, so that uniform cooling air is easily supplied to the fifth battery module 3E in the transverse direction, thereby increasing the cooling efficiency of the battery cells 11 of the fifth battery module 3E.

[0083] The cooling air supplied to the fourth battery module 3D and the fifth battery module 3E flows forward through gaps between the battery cells 11, thereby cooling the battery cells 11. The cooling air flowing forward through the gaps between the battery cells 11 is discharged from the outlet hole 12a of the front surface part 12 into the interior of the receiving case 2.

[0084] As described above, in the on-board battery 1, the first intake fan 20 and the second intake fan 31 are arranged to the right and left of the rear end portion of the housing case 2, respectively. Therefore, the paths of the first intake duct 19 and the second intake duct 30 are short, thereby simplifying the structure of the on-board battery 1 and increasing space efficiency.

[0085] In particular, because the first intake fan 20 and the second intake fan 31 are arranged to the right and left of the rear end portion of the accommodation case 2, rather than behind the accommodation case 2, a large space can be secured behind the accommodation case 2. As described later, the onboard battery 1 is arranged, for example, above a floor panel of a trunk behind the rear seats of the vehicle. Therefore, a spacious trunk space can be ensured, and in addition, sufficient space for a crash cushion can be secured at a rear end portion of the vehicle in the event of a collision, thereby improving impact performance.

[0086] In addition, since the first suction fan 20 and the second suction fan 31 are arranged to the right and left of the rear end portion of the receiving case 2, respectively, the intermediate portion 24 of the first inlet portion 19 and the intermediate portion 34 of the second inlet portion 30 can each be formed as a substantially straight line extending from one side to the other side.

[0087] Therefore, the on-board battery 1 can be downsized in the longitudinal direction, and also the cooling performance can be increased by using cooling air because pressure loss is unlikely to occur in the intermediate section 24 and the intermediate section 34.

[0088] Furthermore, the first inlet duct 19 and the second inlet duct 30 are provided such that the cooling air is supplied to the first battery module 3A, the second battery module 3B and the third battery module 3C via the first inlet duct 19, and also the cooling air is supplied to the fourth battery module 3D and the fifth battery module 3E via the second inlet duct 30.

[0089] Because the cooling air is supplied to the battery modules 3 via two inlet channels, the first inlet channel 19 and the second inlet channel 30, the cooling capacity of the on-board battery 1 can be increased.

[0090] As described above, in the on-board battery 1, the cooling air supplied via the first intake duct 19 and having cooled the battery cells 11 and the cooling air supplied via the second intake duct 30 and having cooled the battery cells 11 are discharged into the accommodation case 2. Therefore, the temperature of each battery module 3 arranged in the accommodation case 2 tends to rise due to the cooling air having performed a cooling operation; in particular, the temperature of the second battery module 3B arranged between the first battery module 3A and the third battery module 3C and below the fourth battery module 3D slightly rises.

[0091] Fig. 13 is a graph illustrating the temperature state during operation of the first battery module 3A and the second battery module 3B. In the graph, (A) represents the temperatures of the battery cells 11 in the first battery module 3A, and (B) represents the temperatures of the battery cells 11 in the second battery module 3B. In addition, cell No. 1 denotes the leftmost battery cell 11, and cell No. 19 denotes the rightmost battery cell 11.

[0092] Regarding the first distribution channel 22A for the first battery module 3A, its connecting portion 29 is arranged at the left end, and the outlet hole 12a of the first battery module 3A is arranged at the right end. Therefore, the cooling air discharged forward from the outlet projections 28a flows from left to right through the interior of the first battery module 3A. Therefore, the temperature of the cooling air becomes higher on the right side where the cooling air flows. That is, the battery cells 11 arranged closer to the right side tend to have higher temperatures, as shown by (A) in Fig. 13 is shown.

[0093] In contrast, with respect to the second distribution channel 22B for the second battery module 3B, its connecting portion 29 is arranged at the right end, and the outlet hole 12a of the second battery module 3B is arranged at the left end. Therefore, the cooling air discharged forward from the outlet projections 28a flows from right to left through the interior of the second battery module 3B. Therefore, the temperature of the cooling air becomes higher on the left side where the cooling air flows. That is, the battery cells 11 arranged closer to the left side tend to have higher temperatures, as shown by (B) in Fig. 13 is shown.

[0094] In this way, in the on-board battery 1, the temperature of the cooling air discharged from the first battery module 3A into the receiving case 2 gradually increases from left to right, and the temperature of the cooling air discharged from the second battery module 3B into the receiving case 2 gradually increases from right to left.

[0095] Therefore, the temperature gradient between the first battery module 3A and the second battery module 3B is inverted. As a result, the internal temperature of the housing 2 is averaged in the transverse direction (see (T) in Fig. 13).

[0096] As described above, in the on-board battery 1, the flow direction of the cooling air in the first battery module 3A is opposite to the flow direction of the cooling air in the second battery module 3B, and the cooling air from the first battery module 3A and the second battery module 3B is discharged to positions spaced apart from each other in the transverse direction.

[0097] Therefore, the temperature gradient between the first battery module 3A and the second battery module 3B is inverted. Therefore, the internal temperature of the housing 2 is averaged in the transverse direction. Furthermore, any component within the housing 2 is unlikely to be locally affected by heat, ensuring proper functions of the individual components arranged within the housing 2.

[0098] As described above, because the second battery module 3B is arranged between the first battery module 3A and the third battery module 3C and below the fourth battery module 3D, its temperature may increase slightly. However, in the first intake unit 17, the length of the second inflow section 26 toward the second battery module 3B is shorter than the length of the first inflow section 25 toward the first battery module 3A.

[0099] Since a flow path of the cooling air flowing through the second inflow portion 26 is short, the cooling air is less influenced by the internal temperature of the receiving case 2 or the like during the flow, thereby ensuring a high cooling performance of the battery cells 11 of the second battery module 3B.

[0100] In the on-board battery 1, the first inflow portion 25 and the second inflow portion 26 are arranged at the left and right end portions, and the third inflow portion 27 is arranged at a center portion in the transverse direction in the first intake unit 17, and the fourth inflow portion 35 and the fifth inflow portion 36 are arranged at the left and right end portions in the second intake unit 18. Therefore, the first intake unit 17 and the second intake unit 18 have substantially symmetrical structures.

[0101] Therefore, when heaters intended to heat the battery modules 3 in cold areas are arranged on the bottom of the battery modules 3, it becomes easy to arrange the heaters symmetrically, thereby homogenizing the heating power for the battery modules 3.

[0102] Furthermore, the first inflow section 25, the second inflow section 26, and the third inflow section 27 are arranged spaced apart from each other in the transverse direction, and the fourth inflow section 35 and the fifth inflow section 36 are arranged spaced apart from each other in the transverse direction. Therefore, the first inflow section 25, the second inflow section 26, and the third inflow section 27 do not overlap in the vertical direction, and the fourth inflow section 35 and the fifth inflow section 36 do not overlap in the vertical direction, thereby downsizing the onboard battery 1 in the vertical direction.

[0103] In order to arrange the second suction fan 31 at a predetermined position, the inlet portion 33 of the second inlet unit 18 has, as a part thereof, a curved portion 33a having a curvature in the transverse direction (see FIG. Fig. 14). Therefore, a pressure loss occurs in the second inlet unit 18 due to the curved section 33a, and the flow characteristics of the cooling air may be slightly worse than in the first inlet unit 17.

[0104] Therefore, the on-board battery 1 is configured to ensure sufficient cooling performance for the fourth battery module 3D and the fifth battery module 3E by reducing the number of battery modules 3 to be cooled by the second inlet unit 18 to two, thereby shortening the flow path of the cooling air.

[0105] A gas outlet channel 43 is arranged on the left side of the battery modules 3 (cf. Fig. 2). The gas outlet channel 43 has two connecting portions 44 (only one of the connecting portions 44 is shown) connected to the gas outlet pipes 15 arranged above the battery modules 3, a protrusion portion 45, and an outlet portion 46. The connecting portions 44 are connected to each other at a distance from each other in the vertical direction, the protrusion portion 45 protrudes to the left from one of the connecting portions 44, and the outlet portion 46 is connected to the protrusion portion 45.

[0106] The connecting portions 44 are arranged in the interior of the receiving housing 2. The connecting portion 44 has three coupling projections 44a projecting to the right, and each of the coupling projections 44a is connected to a left end portion of the corresponding one of the gas outlet pipes 15.

[0107] The projection portion 45 extends through the side wall 8 of the receiving housing 2.

[0108] The outlet portion 46 is arranged along the side wall 8 outside the side wall 8, and one end thereof has an outlet hole 46a.

[0109] When the battery cells 11 malfunction, gas flows from the gas outlet pipes 15 to the connecting portions 44, the protrusion portion 45, and the outlet portion 46, in this order, and is discharged to the outside of the receiving case 2 via the outlet hole 46a.

[0110] In the interior of the receiving housing 2, a first connection box 47 and a second connection box 48 for a control unit are arranged, which serve to control the battery modules 3 (cf. Fig. 1). The first terminal box 47 and the second terminal box 48 are arranged side by side in the transverse direction and above the first battery module 3A in front of the fourth battery module 3D.

[0111] Each of the first junction box 47 and the second junction box 48 contains control components 49 that control power or the like. Examples of the control components 49 include a relay, a fuse, and connection terminals. The first junction box 47 and the second junction box 48 are connected to a power supply circuit (inverter) (not shown) installed in the underbody of the vehicle via power lines described later.

[0112] The cooling air that has been discharged from the distribution channels 22 and has cooled the battery cells 11 of the battery modules 3 is introduced into the area in which the first terminal box 47 and the second terminal box 48 are arranged in the interior of the receiving case 2, and the cooling air cools the first terminal box 47 and the second terminal box 48.

[0113] Generally, from a temperature management perspective, it is desirable to set the temperatures of the battery modules 3 to 60°C or less, and to set the temperatures of the first terminal box 47 and the second terminal box 48 to 100°C or less. Therefore, even when the first terminal box 47 and the second terminal box 48 are cooled by the cooling air having an elevated temperature due to the cooling of the battery cells 11, sufficient cooling performance is ensured using the cooling air for the first terminal box 47 and the second terminal box 48.

[0114] An auxiliary device 50 and a control unit (not shown) are arranged vertically in a right-end portion of the interior of the receiving case 2. The auxiliary device 50 charges the vehicle when the vehicle is at rest, for example, at night, and the control unit controls the entire on-board battery 1.

[0115] The cooling air that has cooled the battery cells 11 is also introduced into the area in which the additional device 50 is arranged in the interior of the receiving housing 2, thereby cooling the additional device 50 and the control unit.

[0116] As described above, in the on-board battery 1, the cooling air is supplied to the battery modules 3 via the first intake duct 19 and the second intake duct 30 from the rear, and five battery modules 3 are provided, wherein the second battery module 3B and the fourth battery module 3D are arranged in an upper and a lower plane, the third battery module 3C and the fifth battery module 3E are arranged in the upper and lower planes, and the first battery module 3A is arranged at the front.

[0117] Therefore, the first battery module 3A, which is located at the front and easily heated, is less affected by the heat generated in the other battery modules 3. This can increase the cooling efficiency of the battery modules 3 and suppress a temperature rise due to heat generation of the battery cells 11.

[0118] Furthermore, the first battery module 3A located at the front is arranged in the middle plane with respect to the battery modules 3 located at the upper and lower planes. This further reduces the influence of heat generated in the rear battery modules 3 and can further suppress a temperature rise due to heat generation of the battery cells 11.

[0119] Although an example in which the number of battery modules 3 arranged within the receiving case 2 is five has been described above, the number of battery modules 3 arranged within the receiving case 2 is at least three. At least two battery modules 3 are arranged in the upper and lower levels, and one battery module 3 is arranged at the front.

[0120] Although a preferred embodiment of the present invention has been described in detail with reference to the accompanying drawings, the present invention is not limited thereto. It will be apparent to those skilled in the art that various modifications or changes are possible within the technical scope of the appended claims or their equivalents. It should be understood that these modifications or changes are also within the technical scope of the present invention.

Claims

[1] On-board battery (1) for a vehicle, comprising: Battery modules (3) each having battery cells (11) arranged therein; a receiving housing (2) which accommodates the battery modules (3); and at least one inlet channel (19, 30) through which cooling air is supplied to the battery modules (3), wherein the cooling air is supplied to the battery modules (3) from the rear via the at least one inlet channel (19, 30), wherein the on-board battery (1) comprises at least four battery modules (3D, 3E, 3B, 3C), wherein at least two of the battery modules (3) are arranged in an upper and a lower level, wherein at least two of the battery modules (3D, 3E, 3B, 3C) are arranged along a longitudinal direction, wherein the on-board battery (1) further comprises a battery module (3A) arranged on a front side, wherein the at least two battery modules (3D, 3E, 3B, 3C) arranged in the upper and lower levels are arranged behind the battery module (3A) arranged at the front, and wherein the one of the battery modules (3A) arranged at the front is arranged in a middle plane with respect to the at least two battery modules arranged in the upper and lower planes. [2] On-board battery (1) according to claim 1, further comprising: a fan (20, 31) connected to the at least one inlet channel (19, 30), wherein the fan (20, 31) is arranged on the left and / or right side in a rear end portion of the receiving housing (2). [3] On-board battery (1) according to one of claims 1 to 2, wherein the at least one inlet channel (19, 30) has a first inlet channel (19) and a second inlet channel (30), wherein the first inlet channel (19) causes the cooling air to be supplied to at least one of the battery modules (3, 3A, 3B, 3C), and wherein the second inlet channel (30) causes the cooling air to be supplied to at least one other of the battery modules (3, 3D, 3E). [4] On-board battery (1) according to claim 3, wherein the on-board battery (1) is arranged so that the cooling air which has been supplied via the first inlet channel (19) and has cooled the at least one battery module (3, 3A, 3B, 3C) is discharged from the at least one battery module (3, 3A, 3B, 3C) into the interior of the receiving housing (2), and the cooling air which has been supplied via the second inlet channel (30) and has cooled the at least one other battery module (3, 3D, 3E) is discharged from the at least one other battery module (3, 3D, 3E) into the interior of the receiving housing (2), and the cooling air supplied via the first inlet duct (19) and the cooling air supplied via the second inlet duct (30) are discharged at positions spaced apart from each other in the transverse direction. [5] On-board battery (1) according to one of claims 1 to 4, wherein the inlet channel (19, 30) has inflow sections (25, 26, 27, 35, 36) via which the cooling air is supplied to a corresponding one of the battery modules (3), and wherein an alignment louvre (37) is arranged in the inflow section (27) which supplies the cooling air to the rearmost battery module (3). [6] On-board battery (1) according to one of claims 1 to 5, wherein the battery cells (11) are aligned, and wherein the battery modules (3) are arranged inside the receiving housing (2) such that the battery cells (11) are arranged along a transverse direction.

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