Power storage device

Abstract

This power storage device has one or more power storage units. The power storage units have a first cell group composed of a plurality of cylindrical cells, and a second cell group composed of a plurality of cylindrical cells. The power storage units have a cooling plate disposed between the first cell group and the second cell group, and comprising a first flow path and a second flow path that pass through in the longitudinal direction. The power storage units have a first end component provided at a first end section of the cooling plate, and comprising a cooling liquid inflow chamber communicating with the first flow path, and a cooling liquid outflow chamber communicating with the second flow path. The power storage units have a second end component provided at a second end section of the cooling plate, and comprising a connection chamber that communicates with both the first flow path and the second flow path.

Description

Power storage device

[0001] The present disclosure relates to an electricity storage device.

[0002] Electric vehicles, hybrid vehicles, and the like have a battery pack as an electricity storage device including a battery module, a controller, etc. Furthermore, cylindrical cells are used as the multiple battery cells that make up the battery module (see Patent Document 1).

[0003] Japanese Patent Application Laid-Open No. 2024-618

[0004] For a battery pack to function properly, it is important not only to keep the temperature of each cylindrical cell within a predetermined temperature range, but also to control the temperature of multiple cylindrical cells to be approximately uniform, i.e., to suppress the temperature difference between the cylindrical cells.

[0005] According to the present disclosure, an energy storage device includes one or more energy storage units. The energy storage units include a first cell group consisting of a plurality of cylindrical cells and a second cell group consisting of a plurality of cylindrical cells. The energy storage units include a cooling plate disposed between the first cell group and the second cell group and having first and second flow paths extending therethrough in the longitudinal direction. The energy storage units include a first end piece provided at a first end of the cooling plate and having a coolant inlet chamber communicating with the first flow paths and a coolant outlet chamber communicating with the second flow paths. The energy storage units include a second end piece provided at a second end of the cooling plate and having a connecting chamber communicating with both the first flow paths and the second flow paths.

[0006] According to the present disclosure, the temperature difference between cylindrical cells can be suppressed.

[0007] FIG. 1 is a diagram showing an example of a vehicle. FIG. 2 is a diagram showing an example of the configuration of a battery pack. FIG. 3 is an exploded perspective view showing a battery module. FIG. 4 is an exploded perspective view showing a portion of a cell assembly. FIG. 5 is an exploded perspective view showing a cell unit constituting a portion of the cell assembly. FIG. 6 is a plan view showing a portion of the cell assembly from the upper cover side. FIG. 7 is a cross-sectional view showing a manifold plate, an inlet hose, and an outlet hose along line F7-F7 in FIG. 6. FIG. 8 is a cross-sectional view showing a manifold plate, a cooling plate, and an end plate along line F8-F8 in FIG. 6. FIG. 9 is a plan view showing a portion of a cell assembly included in an energy storage device according to a second embodiment of the present disclosure. FIG. 10 is a cross-sectional view showing a manifold block and an adapter along line F10-F10 in FIG. 9. FIG. 11 is a cross-sectional view showing a manifold block, an adapter, a cooling plate, and an end plate along line F11-F11 in FIG. 9. FIG. 12 is a plan view showing a portion of a cell assembly included in an energy storage device according to a third embodiment of the present disclosure. FIG. 13 is a cross-sectional view showing the inlet manifold, the outlet manifold, and the adapter along line F13-F13 in FIG. 12. FIG. 14 is a cross-sectional view showing the inlet manifold, the outlet manifold, the adapter, the cooling plate, and the end plate along line F14-F14 in FIG. 12. FIG. 15 is a plan view showing a portion of a cell assembly included in an energy storage device that is a third embodiment of the present disclosure. FIG. 16 is a cross-sectional view showing the inlet manifold, the outlet manifold, and the adapter along line F16-F16 in FIG. 15. FIG. 17 is a cross-sectional view showing the inlet manifold, the outlet manifold, the adapter, the cooling plate, and the end plate along line F17-F17 in FIG. 15. FIG. 18 is a perspective view showing a modified example of the cooling plate.

[0008] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to the accompanying drawings. In the following description, identical or substantially identical configurations and elements are designated by the same reference numerals and will not be described repeatedly.

[0009] <First Embodiment> <Vehicle> Fig. 1 is a diagram showing an example of a vehicle 10. The vehicle 10 shown in Fig. 1 is equipped with a power storage device according to a first embodiment of the present disclosure. As shown in Fig. 1, the vehicle 10 has an electric axle 13 including an electric motor 11 and a differential mechanism 12, and a battery pack (power storage device) 14 provided under the vehicle body. The battery pack 14 is connected to the electric motor 11 of the electric axle 13 via an inverter 15. The battery pack 14 is also connected to a cooling system 18 including a water pump 16 and a radiator 17. The differential mechanism 12 of the electric axle 13 is coupled to wheels 20 via axles 19.

[0010] <Battery Pack> Fig. 2 is a diagram showing an example of the configuration of the battery pack 14. As shown in Fig. 2, the battery pack 14 includes a battery case 21, a plurality of battery modules 22, 23 housed in the battery case 21, and a junction box 24 provided in the battery case 21. The junction box 24 is provided with a terminal block 25, high-voltage connectors 26, 27, an electronic control unit 28, and the like. The inverter 15 is connected to the high-voltage connectors 26, 27 of the junction box 24 via high-voltage cables 29, 30.

[0011] The positive terminal 22a of the battery module 22 is connected to the terminal block 25 via a module bus bar 31, and the negative terminal 23b of the battery module 23 is connected to the terminal block 25 via a module bus bar 32. The negative terminal 22b of the battery module 22 and the positive terminal 23a of the battery module 23 are connected to each other via a module bus bar 33. In the illustrated example, the battery pack 14 is provided with two battery modules 22, 23, but this is not limited thereto. The battery pack 14 may be provided with one battery module, or three or more battery modules. In the illustrated example, the battery modules 22, 23 are connected in series to each other, but this is not limited thereto. The battery modules 22, 23 may be connected in parallel to each other.

[0012] The cooling system 18 includes a water pump (cooling pump) 16 that pumps coolant and a radiator 17 that serves as a heat exchanger. A discharge pipe 34 is connected to a discharge port 16a of the water pump 16, and a suction pipe 36 is connected to a suction port 16b of the water pump 16 via a connection pipe 35 and the radiator 17. The discharge pipe 34a branching from the discharge pipe 34 is connected to an elbow joint 37 of the battery module 22, and the discharge pipe 34b branching from the discharge pipe 34 is connected to an elbow joint 38 of the battery module 23. The suction pipe 36a branching from the suction pipe 36 is connected to an elbow joint 39 of the battery module 22, and the suction pipe 36b branching from the suction pipe 36 is connected to an elbow joint 40 of the battery module 23.

[0013] The coolant discharged from the water pump 16 is supplied from the discharge pipe 34 to the battery module 22 via the discharge pipe 34a, and is also supplied from the discharge pipe 34 to the battery module 23 via the discharge pipe 34b. The coolant that has flowed through the battery module 22 is supplied to the radiator 17 via the intake pipe 36a to the intake pipe 36, and the coolant that has flowed through the battery module 23 is supplied to the radiator 17 via the intake pipe 36b to the intake pipe 36. The coolant that has passed through the radiator 17 and cooled is then sucked back into the water pump 16 via the connection pipe 35, and is again pumped from the water pump 16 toward the battery modules 22, 23.

[0014] In this way, in the cooling system 18, by driving the water pump 16, the coolant can be circulated between the battery modules 22, 23 and the radiator 17, thereby cooling the battery modules 22, 23. The cooling path 41, which circulates the coolant, is made up of the discharge pipes 34, 34a, 34b, the suction pipes 36, 36a, 36b, and the connection pipe 35.

[0015] <Battery Module> In the above description, the battery modules are denoted by the reference numerals 22 and 23, the positive terminals are denoted by the reference numerals 22a and 23a, and the negative terminals are denoted by the reference numerals 22b and 23b. However, in the following description, the battery module is denoted by the reference numeral 50, the positive terminal is denoted by the reference numeral 50a, and the negative terminal is denoted by the reference numeral 50b.

[0016] FIG. 3 is an exploded perspective view showing the battery module 50. Because the battery module 50 has an elongated shape, FIG. 3 shows both ends of the battery module 50 and their vicinity. FIG. 4 is an exploded perspective view showing a portion of the cell assembly 56, and FIG. 5 is an exploded perspective view showing a cell unit 62 that constitutes part of the cell assembly 56. FIG. 6 is a plan view showing part of the cell assembly 56 from the upper cover 51 side. As with FIG. 3, FIGS. 4, 5, and 6 also show both ends of the cell assembly 56 and the cell unit 62 and their vicinity.

[0017] As shown in FIG. 3 , the battery module 50 has a housing 54 consisting of an upper cover 51, a lower cover 52, and a side cover 53. The housing 54 contains a cell assembly 56 consisting of a number of cylindrical cells 55, as well as an insulating plate 57 attached to an electrode surface 56a at the lower end of the cell assembly 56. The housing 54 also contains a plurality of bus bars 58, 59, 60, and 61 disposed between the insulating plate 57 and the lower cover 52. The bus bar 60 is integrally provided with a positive terminal 50a, and the bus bar 61 is integrally provided with a negative terminal 50b. The bus bars 58, 59, 60, and 61 are connected to the positive and negative electrodes of the cylindrical cells 55.

[0018] As shown in Fig. 4, the cell assembly 56 includes a plurality of cell units (energy storage units) 62 and a plurality of separators 63 arranged between the cell units 62. As shown in Fig. 5, each cell unit 62 includes a first cell group 64 consisting of a plurality of cylindrical cells 55 arranged in a row, a second cell group 65 consisting of a plurality of cylindrical cells 55 arranged in a row, and a cooling plate 66 arranged between the first cell group 64 and the second cell group 65. A manifold plate (first end part) 67 is provided at a first end 66a of the cooling plate 66, and an end plate (second end part) 68 is provided at a second end 66b of the cooling plate 66.

[0019] As shown in the enlarged portion of Figure 5, the cooling plate 66 has a hollow structure with a partition wall 70 located in the vertical center. The cooling plate 66 is an extruded material manufactured by extruding a billet made of an aluminum alloy or the like. The extruded cooling plate 66 thus has a pair of flow paths defined by the partition wall 70, that is, a feed flow path (first flow path) 71 and a return flow path (second flow path) 72 that penetrate the cooling plate in the longitudinal direction D1.

[0020] As shown by arrow X1 in Figure 6, the cylindrical cells 55 constituting the first cell group 64 and the cylindrical cells 55 constituting the second cell group 65 are arranged offset from each other in the longitudinal direction D1 of the cooling plate 66. This allows a large number of cylindrical cells 55 to be efficiently accommodated within the housing 54, thereby increasing the power storage capacity of the battery module 50. In addition, to ensure a sufficient contact area between the cooling plate 66 and the cylindrical cells 55, the side surface of the cooling plate 66 is formed with multiple curved surfaces in a serpentine shape. Note that a potting material (not shown) is injected into the gaps between the cylindrical cells 55 provided in the cell assembly 56.

[0021] <Cooling Channel Structure> Figure 7 is a cross-sectional view taken along line F7-F7 in Figure 6, showing the manifold plate 67, the inlet hose 80, and the outlet hose 81. Figure 8 is a cross-sectional view taken along line F8-F8 in Figure 6, showing the manifold plate 67, the cooling plate 66, and the end plate 68.

[0022] 6, 7, and 8, the manifold plate 67 provided at the first end 66a of the cooling plate 66 is composed of a pair of plate pieces 73, 74. As shown in Fig. 7, the plate piece 73 has joints 73a, 73b and a partition wall 73c, and the plate piece 74 has joints 74a, 74b and a partition wall 74c. The manifold plate 67 is attached to the first end 66a of the cooling plate 66 by combining the pair of plate pieces 73, 74 so as to sandwich the first end 66a of the cooling plate 66.

[0023] The manifold plate 67 is partitioned by partition walls 73c, 74c into an inlet chamber (coolant inlet chamber) 75 and an outlet chamber (coolant outlet chamber) 76. That is, the manifold plate 67 has the inlet chamber 75 that communicates with the feed flow path 71 and the outlet chamber 76 that communicates with the return flow path 72. The joints 73a, 74a of the manifold plate 67 communicate with the inlet chamber 75, and the joints 73b, 74b of the manifold plate 67 communicate with the outlet chamber 76.

[0024] 6 and 8, the end plate 68 provided at the second end 66b of the cooling plate 66 is composed of a pair of plate pieces 77, 78. The end plate 68 is attached to the second end 66b of the cooling plate 66 by combining the pair of plate pieces 77, 78 so as to sandwich the second end 66b of the cooling plate 66. Also, as shown in FIG. 8, the end plate 68 has a connecting chamber 79 that communicates with both the feed channel 71 and the return channel 72. In other words, the feed channel 71 and the return channel 72 of the cooling plate 66 communicate with each other via the connecting chamber 79 of the end plate 68.

[0025] The manifold plate 67 and the cooling plate 66 are joined to each other by brazing or another joining method. Similarly, the end plate 68 and the cooling plate 66 are joined to each other by brazing or another joining method. In the illustrated example, the manifold plate 67 is formed by a pair of plate pieces 73, 74, but this is not limited thereto and the manifold plate 67 may be integrally formed. Similarly, in the illustrated example, the end plate 68 is formed by a pair of plate pieces 77, 78, but this is not limited thereto and the end plate 68 may be integrally formed.

[0026] As shown in Figure 7, in a pair of adjacent manifold plates 67, the joint 73a of one manifold plate 67 and the joint 74a of the other manifold plate 67 face each other. The joints 73a and 74a are connected to each other via an inlet hose 80. Similarly, in a pair of adjacent manifold plates 67, the joint 73b of one manifold plate 67 and the joint 74b of the other manifold plate 67 face each other. The joints 73b and 74b are connected to each other via an outlet hose 81. In this way, the inlet hose 80 that connects the pair of adjacent inlet chambers 75 and the outlet hose 81 that connects the pair of adjacent outlet chambers 76 are arranged between the pair of adjacent manifold plates 67.

[0027] 7, elbow joints 37, 38 connected to the discharge pipes 34a, 34b are attached to joint 73a of the manifold plate 67, of the plurality of manifold plates 67, that is arranged at the end of the cell assembly 56. Furthermore, elbow joints 39, 40 connected to the suction pipes 36a, 36b are attached to joint 73b of the manifold plate 67, of the plurality of manifold plates 67, that is arranged at the end of the cell assembly 56.

[0028] In this way, elbow fittings 37, 38 are attached to fitting 73a, and elbow fittings 39, 40 are attached to fitting 73b. As a result, the inlet chamber 75 and the outlet chamber 76 of the manifold plate 67 are connected to each other via a cooling path 41 including the radiator 17 and the water pump 16, i.e., the cooling path 41 shown in Figure 2. Furthermore, as indicated by arrow α2 in Figure 7, plugs 82, 83 that close fittings 74a, 74b are attached to the fittings 74a, 74b of the manifold plate 67 that is arranged at the end of the cell assembly 56, out of the multiple manifold plates 67.

[0029] <Coolant Flow> As described above, the coolant discharged from the water pump 16 is supplied to the battery module 50 from the discharge pipe 34 via the discharge pipes 34a and 34b. That is, as shown by arrow FL1 in FIG. 7 , the coolant that flows into the elbow joints 37 and 38 is distributed from each inlet chamber 75 to the feed channels 71 of each cooling plate 66. Next, as shown by arrow FL2 in FIG. 8 , the coolant that flows into the feed channels 71 flows toward the end plate 68 while cooling the cylindrical cells 55. Furthermore, as shown by arrow FL3, the coolant that reaches the connecting chamber 79 of the end plate 68 from the feed channels 71 reverses its flow direction and is guided to the return channels 72 of the cooling plate 66. Furthermore, as shown by arrow FL4, the coolant that flows into the return channels 72 flows toward the manifold plate 67 while cooling the cylindrical cells 55. As shown by arrow FL5 in FIG. 7, the coolant that has reached the outflow chamber 76 of the manifold plate 67 from the return flow passage 72 flows toward the elbow joints 39, 40 to which the intake pipes 36a, 36b are connected.

[0030] As described above, the cooling plate 66 is provided with the feed flow path 71 and the return flow path 72, which reduces the temperature difference between the cylindrical cells 55 cooled by the cooling plate 66. In other words, the temperature of the coolant passing through the cooling plate 66 gradually increases, so that the temperature is lowest immediately after it flows into the feed flow path 71, as indicated by symbol β1, and the temperature is highest immediately before it flows out of the return flow path 72, as indicated by symbol β2. In other words, the sum of the temperature of the coolant cooling the upper and lower cylindrical cells can be made closer to each other for each cylindrical cell 55, thereby reducing the temperature difference between the cylindrical cells 55. This allows the temperatures of the multiple cylindrical cells 55 to be controlled to be approximately uniform, ensuring proper functioning of the battery pack 14.

[0031] Second Embodiment Fig. 9 is a plan view showing a portion of a cell assembly 90 included in a battery pack (power storage device) according to a second embodiment of the present disclosure. Fig. 10 is a cross-sectional view showing a manifold block 92 and an adapter 91 taken along line F10-F10 in Fig. 9. Fig. 11 is a cross-sectional view showing the manifold block 92, the adapter 91, the cooling plate 66, and the end plate 68 taken along line F11-F11 in Fig. 9. In Figs. 9, 10, and 11, parts and portions similar to those shown in Figs. 6, 7, and 8 are designated by the same reference numerals, and descriptions thereof will be omitted.

[0032] As shown in Fig. 9, an adapter (first end part) 91 is provided at the first end 66a of each cooling plate 66, and a manifold block 92 is attached to the multiple adapters 91. In other words, the cell assembly 90 has multiple cell units (power storage units) 90a configured with the adapters 91. As shown in Figs. 10 and 11, the adapter 91 has a partition wall 94 that faces the partition wall 70 of the cooling plate 66. The adapter 91 is partitioned by the partition wall 94 into an inlet chamber (coolant inlet chamber) 95 that communicates with the feed flow path 71 and an outlet chamber (coolant outlet chamber) 96 that communicates with the return flow path 72.

[0033] 10 , discharge pipes 34a and 34b that guide the coolant from the water pump 16 are connected to the manifold block 92 via joints 97. In addition, suction pipes 36a and 36b that guide the coolant toward the water pump 16 are connected to the manifold block 92 via joints 98.

[0034] The manifold block 92 has a main inlet flow passage (inlet flow passage) 100 that communicates with the discharge pipes 34a and 34b, and branch inlet flow passages (inlet flow passages) 101 that branch off from the main inlet flow passage 100. As shown in Figures 10 and 11 , the branch inlet flow passage 101 of the manifold block 92 is connected to the inlet chamber 95 of the adapter 91. In other words, the inlet chambers 95 provided in the adapters 91 are connected to each other via the main inlet flow passage 100 and the branch inlet flow passages 101 of the manifold block 92.

[0035] Similarly, the manifold block 92 has a main outlet flow passage (outlet flow passage) 102 that communicates with the suction pipes 36a, 36b, and branch outlet flow passages (outlet flow passages) 103 that branch off from the main outlet flow passage 102. The branch outlet flow passage 103 of the manifold block 92 is connected to the outlet chamber 96 of the adapter 91. In other words, the outlet chambers 96 provided in each adapter 91 are connected to each other via the main outlet flow passage 102 and the branch outlet flow passages 103 of the manifold block 92.

[0036] As explained above, even when the manifold block 92 and the adapter 91 are used, the coolant can be supplied to the feed flow path 71 of each cooling plate 66 and can be collected from the return flow path 72 of each cooling plate 66. This allows the coolant to flow from the feed flow path 71 to the return flow path 72 of the cooling plate 66, thereby suppressing the temperature difference between the cylindrical cells 55 cooled by the cooling plate 66. Moreover, by attaching one manifold block 92 to multiple adapters 91, multiple flow paths can be connected, which greatly facilitates the assembly of the battery module.

[0037] Third Embodiment Fig. 12 is a plan view showing a portion of a cell assembly 110 included in a battery pack (power storage device) according to a third embodiment of the present disclosure. Fig. 13 is a cross-sectional view showing the inlet manifold 112, the outlet manifold 122, and the adapter 111 taken along line F13-F13 in Fig. 12. Fig. 14 is a cross-sectional view showing the inlet manifold 112, the outlet manifold 122, the adapter 111, the cooling plate 66, and the end plate 68 taken along line F14-F14 in Fig. 12. In Figs. 12, 13, and 14, parts and portions similar to those shown in Figs. 6, 7, and 8 are designated by the same reference numerals, and their description will be omitted.

[0038] 12 , 13 , and 14 , an adapter (first end part) 111 is provided at the first end 66 a of each cooling plate 66, and an inlet manifold (inlet piping) 112 and an outlet manifold (outlet piping) 122 are attached to the multiple adapters 111. That is, the cell assembly 110 has multiple cell units (power storage units) 110 a configured with the adapters 111. Also, as shown in FIGS. 13 and 14 , the adapter 111 has a partition wall 130 facing the partition wall 70 of the cooling plate 66. The adapter 111 is partitioned by the partition wall 130 into an inlet chamber (coolant inlet chamber) 131 that communicates with the feed flow path 71 and an outlet chamber (coolant outlet chamber) 132 that communicates with the return flow path 72.

[0039] 12 and 14 , the inlet manifold 112 is connected to the discharge pipes 34a and 34b via joints 114, which guide the coolant from the water pump 16. The inlet manifold 112 has a main inlet pipe (main inlet pipe section) 115 that communicates with the discharge pipes 34a and 34b, and a branch inlet pipe (branch inlet pipe section) 116 that branches off from the main inlet pipe 115. As indicated by the dashed-dotted line L1, the branch inlet pipe 116 extends in the longitudinal direction D1 of the cooling plate 66 and is connected to the inlet chambers 131 of the adapters 111. In this way, the inlet chambers 131 provided in the adapters 111 are connected to each other via the inlet manifold 112.

[0040] Similarly, the outlet manifold 122 is connected to the suction pipes 36a, 36b via joints 124, which guide the coolant toward the water pump 16. The outlet manifold 122 has a main outlet pipe (main outlet pipe section) 125 that communicates with the suction pipes 36a, 36b, and a branch outlet pipe (branch outlet pipe section) 126 that branches off from the main outlet pipe 125. As shown by the dashed-dotted line L2 in FIG. 14 , the branch outlet pipe 126 extends in the longitudinal direction D1 of the cooling plate 66 and is connected to the outlet chamber 132 of the adapter 111. In this way, the outlet chambers 132 provided in each adapter 111 are connected to each other via the outlet manifold 122.

[0041] As explained above, even when the inlet manifold 112, the outlet manifold 122, and the adapter 111 are used, the coolant can be supplied to the feed flow path 71 of each cooling plate 66 and can be recovered from the return flow path 72 of each cooling plate 66. This allows the coolant to flow from the feed flow path 71 to the return flow path 72 of the cooling plate 66, thereby suppressing the temperature difference between the cylindrical cells 55 cooled by the cooling plate 66. Moreover, by attaching the inlet manifold 112 and the outlet manifold 122 to multiple adapters 111, multiple flow paths can be connected, which greatly facilitates the assembly of the battery module.

[0042] Fourth Embodiment Fig. 15 is a plan view showing a portion of a cell assembly 140 included in a battery pack (power storage device) according to a third embodiment of the present disclosure. Fig. 16 is a cross-sectional view showing the inlet manifold 142, the outlet manifold 152, and the adapter 141 taken along line F16-F16 in Fig. 15. Fig. 17 is a cross-sectional view showing the inlet manifold 142, the outlet manifold 152, the adapter 141, the cooling plate 66, and the end plate 68 taken along line F17-F17 in Fig. 15. In Figs. 15, 16, and 17, parts and portions similar to those shown in Figs. 6, 7, and 8 are designated by the same reference numerals, and their description will be omitted.

[0043] 15 , 16 , and 17 , an adapter (first end part) 141 is provided at the first end 66 a of each cooling plate 66, and an inlet manifold (inlet piping) 142 and an outlet manifold (outlet piping) 152 are attached to the multiple adapters 141. That is, the cell assembly 140 has multiple cell units (power storage units) 140 a configured with the adapters 141. Also, as shown in FIGS. 16 and 17 , the adapter 141 has a partition wall 160 facing the partition wall 70 of the cooling plate 66. The adapter 141 is partitioned by the partition wall 160 into an inlet chamber (coolant inlet chamber) 161 that communicates with the feed flow path 71 and an outlet chamber (coolant outlet chamber) 162 that communicates with the return flow path 72.

[0044] As shown in Figures 15 and 17, the inlet manifold 142 is connected to the discharge pipes 34a and 34b via joints 143, which guide the coolant from the water pump 16. The inlet manifold 142 has a main inlet pipe (main inlet pipe section) 144 that communicates with the discharge pipes 34a and 34b, and a branch inlet pipe (branch inlet pipe section) 145 that branches off from the main inlet pipe 144. As shown by the dashed-dotted line L3 in Figure 15, the branch inlet pipe 145 extends in a direction inclined with respect to the longitudinal direction D1 of the cooling plate 66, and is connected to the inlet chambers 161 of the adapters 141 via hoses 146 and joints 147. In this way, the inlet chambers 161 provided in each adapter 141 are connected to each other via the inlet manifold 142.

[0045] Similarly, the suction pipes 36a, 36b that guide coolant toward the water pump 16 are connected to the outlet manifold 152 via joints 153. The outlet manifold 152 has a main outlet pipe (main outlet pipe section) 154 that communicates with the suction pipes 36a, 36b and a branch outlet pipe (branch outlet pipe section) 155 that branches off from the main outlet pipe 154. As shown by the dashed-dotted line L4 in FIG. 15 , the branch outlet pipe 155 extends in a direction inclined with respect to the longitudinal direction D1 of the cooling plate 66, and is connected to the outlet chamber 162 of the adapter 141 via a hose 156 and a joint 157. In this way, the outlet chambers 162 provided in each adapter 141 are connected to each other via the outlet manifold 152.

[0046] As described above, even when the inlet manifold 142, the outlet manifold 152, and the adapter 141 are used, the coolant can be supplied to the feed channel 71 of each cooling plate 66 and collected from the return channel 72 of each cooling plate 66. This allows the coolant to flow from the feed channel 71 to the return channel 72 of the cooling plate 66, thereby suppressing the temperature difference between the cylindrical cells 55 cooled by the cooling plate 66. Moreover, by attaching the inlet manifold 142 and the outlet manifold 152 to multiple adapters 141, multiple flow channels can be connected, greatly facilitating the assembly of the battery module. Furthermore, by tilting the branch inlet pipe 145 and the branch outlet pipe 155 with respect to the longitudinal direction D1 of the cooling plate 66, the piping space for the coolant can be shortened in the longitudinal direction D1.

[0047] <Modifications> The present disclosure is not limited to the above-described embodiment and may be modified in various ways without departing from the spirit and scope of the present disclosure. FIG. 18 is a perspective view showing a modification of a cooling plate. As shown in FIG. 18, the cooling plate 170 has a hollow structure with three partition walls 171, 172, and 173. That is, the cooling plate 170 has two feed channels (first channels) 174 and 175 and two return channels (second channels) 176 and 177 that penetrate the cooling plate 170 in the longitudinal direction. Even when the cooling plate 170 is provided with multiple feed channels 174 and 175 and multiple return channels 176 and 177, it can function in the same manner as the cooling plate 66 described above. Note that a single cooling plate may have three or more feed channels and three or more return channels.

[0048] In the example shown in Figure 6, seven cell units 62 are provided in the cell assembly 56, but this is not limited thereto, and one cell unit 62 may be provided in the cell assembly 56. Note that six or fewer cell units 62 may be provided in the cell assembly 56, or eight or more cell units 62 may be provided in the cell assembly 56. In the example shown in the figure, the battery pack 14 is provided in an electric vehicle, but this is not limited thereto, and the battery pack 14 may also be used in other devices. Furthermore, as the cylindrical cells 55, not only batteries such as lithium-ion batteries but also storage cells such as capacitors may be used.

[0049] 14...battery pack (electricity storage device), 16...water pump (cooling pump), 17...radiator, 22, 23...battery module, 41...cooling path, 50...battery module, 55...cylindrical cell, 62...cell unit (electricity storage unit), 64...first cell group, 65...second cell group, 66...cooling plate, 66a...first end, 66b...second end, 67...manifold plate (first end part), 68...end plate (second end part), 71...feed channel (first channel), 72...return channel (second flow path), 75...inlet chamber (coolant inlet chamber), 76...outlet chamber (coolant outlet chamber), 79...connection chamber, 80...inlet hose, 81...outlet hose, 90a...cell unit (electricity storage unit), 91...adapter (first end part), 92...manifold block, 95...inlet chamber (coolant inlet chamber), 96...outlet chamber (coolant outlet chamber), 100...main inlet flow path (inlet flow path), 101...branch inlet flow path (inlet flow path), 102...main outlet flow path (outlet flow path), 103...branch outlet flow path (outlet flow path), 110a... Cell unit (electricity storage unit), 111... adapter (first end part), 112... inlet manifold (inlet piping), 115... main inlet pipe (main inlet pipe section), 116... branch inlet pipe (branch inlet pipe section), 122... outlet manifold (outlet piping), 125... main outlet pipe (main outlet pipe section), 126... branch outlet pipe (branch outlet pipe section), 131... inlet chamber (coolant inlet chamber), 132... outlet chamber (coolant outlet chamber), 140a... cell unit (electricity storage unit), 141... adapter (first end part), 1 end part), 142... inlet manifold (inlet piping), 144... main inlet pipe (main inlet pipe section), 145... branch inlet pipe (branch inlet pipe section), 152... outlet manifold (outlet piping), 154... main outlet pipe (main outlet pipe section), 155... branch outlet pipe (branch outlet pipe section), 161... inlet chamber (coolant inlet chamber), 162... outlet chamber (coolant outlet chamber), 170... cooling plate, 174, 175... feed flow path (first flow path), 176, 177... return flow path (second flow path), D1... longitudinal direction

Claims

1. An electricity storage device having one or more electricity storage units, each of the electricity storage units comprising: a first cell group consisting of a plurality of cylindrical cells; a second cell group consisting of a plurality of cylindrical cells; a cooling plate disposed between the first cell group and the second cell group and having first and second flow paths penetrating the longitudinal direction; a first end piece provided at a first end of the cooling plate and having a coolant inlet chamber communicating with the first flow paths and a coolant outlet chamber communicating with the second flow paths; and a second end piece provided at a second end of the cooling plate and having a connection chamber communicating with both the first flow path and the second flow path.

2. The electricity storage device according to claim 1, wherein the cooling plate is an extruded material.

3. The electric storage device according to claim 1, wherein the cooling plate comprises a plurality of the first flow paths and a plurality of the second flow paths.

4. The electric storage device according to claim 1, wherein the coolant inlet chamber and the coolant outlet chamber are connected to each other via a cooling path equipped with a radiator and a cooling pump.

5. An electric storage device according to claim 1, wherein a plurality of the electric storage units are provided, and an inlet hose connecting the pair of adjacent cooling liquid inlet chambers and an outlet hose connecting the pair of adjacent cooling liquid outlet chambers are arranged between the pair of adjacent first end parts.

6. An electric storage device according to claim 1, wherein a plurality of said electric storage units are provided, said plurality of cooling liquid inlet chambers are connected to one another via inlet flow paths of manifold blocks attached to said plurality of first end components, and said plurality of cooling liquid outlet chambers are connected to one another via outlet flow paths of said manifold blocks.

7. An electric storage device according to claim 1, wherein a plurality of the electric storage units are provided, the plurality of coolant inlet chambers are connected to one another via inlet pipes attached to the plurality of first end parts, the plurality of coolant outlet chambers are connected to one another via outlet pipes attached to the plurality of first end parts, the inlet pipe comprises a main inlet pipe section and a plurality of branch inlet pipe sections branching from the main inlet pipe section and connected to each of the plurality of coolant inlet chambers, and the outlet pipe comprises a main outlet pipe section and a plurality of branch outlet pipe sections branching from the main outlet pipe section and connected to each of the plurality of coolant outlet chambers.

8. An electric storage device according to claim 7, wherein the branched inlet pipe section extends in the longitudinal direction of the cooling plate, and the branched outlet pipe section extends in the longitudinal direction of the cooling plate.

9. An electric storage device according to claim 7, wherein the branched inlet pipe section extends in a direction inclined relative to the longitudinal direction of the cooling plate, and the branched outlet pipe section extends in a direction inclined relative to the longitudinal direction of the cooling plate.

Images