Cooling Structure of Secondary Battery

Abstract

To provide a secondary battery cooling structure capable of quickly cooling a secondary battery by making it possible to push gas generated in a space through a resin layer to the outside of an exterior body along with the flow of fluid.SOLUTION: A secondary battery cooling structure according to the present invention includes: a circulation circuit 10 that circulates a fluid; an exterior body 3 having a connection port 7 communicating with the circulation circuit 10; and a flat plate-like electrode laminate 4 that is housed in the exterior body 3 and sealed with a resin film. The exterior body 3 and the electrode laminate 4 are provided apart from each other, and the fluid flows between the exterior body 3 and the electrode laminate 4.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a cooling structure for secondary batteries.

Background Art

[0002] In recent years, electric vehicles powered by electricity and hybrid cars that run by combining an engine and a motor have attracted attention, and various battery modules to be mounted on them have been proposed.

[0003] For example, Patent Document 1 discloses a battery module (secondary battery) including an exterior material for a battery element made of a laminate film having a structure in which two or more resin film layers are laminated. The battery module described in Patent Document 1 has an exterior body that houses a resin layer having gas permeability, and gas generated in the space through the resin layer is discharged to the outside through a safety valve mechanism.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In the cooling structure of the battery module described in Patent Document 1, gas may accumulate at the corners inside the exterior body or between the inner wall inside the exterior body and the resin layer, and gas removal may not be sufficient. And when gas removal is not sufficient, it may hinder the flow of a fluid such as a refrigerant, and it may take time to cool the battery module.

[0006] Therefore, an object of the present invention is to provide a cooling structure for a secondary battery that can quickly cool the secondary battery while sufficiently removing gas generated inside the secondary battery.

Means for Solving the Problems

[0007] [1] The cooling structure of a secondary battery according to one aspect of the present invention includes a circulation circuit for circulating a fluid, an exterior body having a connection port communicating with the circulation circuit, and a flat electrode laminate housed in the exterior body and sealed with a resin film, and is characterized in that the exterior body and the electrode laminate are provided separately from each other, and the fluid circulates between the exterior body and the electrode laminate.

[0008] [2] In the cooling structure of the secondary battery of [1] above, the connection port has a first connection port and a second connection port, the exterior body has a substantially rectangular shape formed by a pair of first exterior body sides and a pair of second exterior body sides orthogonal to the first exterior body sides in plan view, the first connection port and the second connection port are provided on the first exterior body side, the electrode laminate has, in plan view, a first electrode laminate side facing the pair of first exterior body sides and a second electrode laminate side facing the pair of second exterior body sides, and has a substantially rectangular shape smaller than the exterior body, a first cooling flow path is provided between the first exterior body side and the first electrode laminate side, a second cooling flow path is provided between the second exterior body side and the second electrode laminate side, and the cross-sectional area of the first cooling flow path may be smaller than the cross-sectional area of the second cooling flow path.

[0009] [3] In the cooling structure of the secondary battery of [2] above, the first connection port and the second connection port may be provided in a region where the first cooling flow path and the second cooling flow path intersect.

[0010] [4] In the cooling structure of the secondary battery of [2] above, the first connection port and the second connection port may be provided at positions overlapping the first cooling flow path. [Effect of the Invention]

[0011] According to the aspect of [1] above, a fluid circulates between the exterior body and the electrode laminate. Therefore, it is possible to provide a cooling structure for a secondary battery that can quickly cool the secondary battery while sufficiently removing the gas generated inside the secondary battery.

[0012] In the aspect of [2] above, the cross-sectional area of the first cooling channel is smaller than that of the second cooling channel. Therefore, by increasing the flow velocity of the fluid flowing through the first cooling channel and suppressing the flow velocity of the fluid flowing through the second cooling channel, it is possible to equalize the flow rate distribution of the fluid while enhancing the exhaustibility of the gas generated in the fluid.

[0013] In the aspect of [3] above, the first connection port and the second connection port are respectively provided in the region where the first cooling channel and the second cooling channel intersect. Therefore, it becomes possible to more efficiently remove the gas staying in the region where the first cooling channel and the second cooling channel intersect by utilizing the flow velocity of the fluid flowing through the first cooling channel.

[0014] In the aspect of [4] above, the first connection port and the second connection port are provided at positions overlapping with the first cooling channel 51. Therefore, the flow velocity of the fluid flowing through the first cooling channel can be made faster. Thus, it becomes possible to more efficiently remove the gas staying in the region where the first cooling channel and the second cooling channel intersect by utilizing the flow velocity of the fluid flowing through the first cooling channel.

Brief Description of the Drawings

[0015]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Modes for Carrying Out the Invention

[0016] Hereinafter, embodiments of the present invention will be described with reference to the drawings. The drawings used in the following description may, for the sake of clarity of features, show enlarged portions of the features for convenience, and the shapes, dimensional ratios, etc. of each component are not limited to those shown.

[0017] [First Embodiment] FIG. 1 is a flowchart schematically showing a cooling structure 100 of a secondary battery 1 according to an embodiment of the present invention. As shown in FIG. 1, the cooling structure 100 of the secondary battery 1 includes a circulation circuit 10 for circulating a fluid, and a power storage module pack 20 including a plurality of secondary batteries 1.

[0018] A fluid, which is a cooling solvent (refrigerant), circulates in the circulation circuit 10 and the power storage module pack 20. As the fluid, a gas or a liquid can be used. For example, the fluid is an insulating liquid such as a fluorine-based inert liquid. Since the fluid is an insulating liquid, it can directly cool the internal bus bar 14 described later, and the cooling performance can be enhanced.

[0019] The circulation circuit 10 includes a liquid separation tank ST, a radiator RAD, a thermo valve SV, a pump P, and a heater H. In the present embodiment, the circulation circuit 10 includes the heater H, but the heater H may not be provided. In the following description, when a fluid is circulated through the circulation circuit 10, with reference to the power storage module pack 20, the direction in which the liquid flows out from the power storage module pack 20 is referred to as the "upstream side", and the direction in which the fluid flows into the power storage module pack 20 is referred to as the "downstream side" for explanation.

[0020] The gas-liquid separation tank ST separates the gas and liquid of the fluid flowing in from the power storage module pack 20. On the downstream side of the gas-liquid separation tank ST, the liquid separated by the gas-liquid separation tank ST circulates as the fluid. The upstream side of the gas-liquid separation tank ST is connected to the power storage module pack 20. The downstream side of the gas-liquid separation tank ST is connected to the upstream side of the radiator RAD and the upstream side of the thermo valve SV.

[0021] The radiator RAD performs heat exchange between the fluid and the outside air. The downstream side of the radiator RAD is connected to the upstream side of the thermovalve SV. The thermovalve SV is a three-way valve that switches according to the temperature of the fluid. The downstream side of the thermovalve SV is connected to the upstream side of the pump P. The pump P supplies the fluid to the circulation circuit 10 via the power storage module pack 20 according to the required output of the power storage module pack 20. The downstream side of the pump P is connected to the upstream side of the heater H.

[0022] The heater H has a function of adjusting the temperature of the fluid. The downstream side of the heater H is connected to the power storage module pack 20. When the heater H is not provided, the downstream side of the pump P is connected to the power storage module pack 20.

[0023] FIG. 2 is a plan view schematically showing the secondary battery 1 included in the cooling structure 100 according to an embodiment of the present invention. FIG. 3 is a cross-sectional view taken along line III-III of FIG. 2. FIG. 4 is a cross-sectional view taken along line IV-IV of FIG. 2. FIG. 5 is a cross-sectional view taken along line V-V of FIG. 2.

[0024] The secondary battery 1 is a rectangular plate-like member in plan view. The secondary battery 1 is, for example, a pouch-type lithium-ion secondary battery. In FIGS. 2 to 5, the direction D1 indicates the longitudinal direction of the secondary battery 1 in plan view. The direction D2 indicates the width direction of the secondary battery 1 in plan view. The direction D3 is the depth direction of the secondary battery 1 in plan view. As shown in FIGS. 2 to 5, the secondary battery 1 includes an exterior body 3, a flat electrode laminate 4 housed in the exterior body 3, and an external terminal 11.

[0025] The exterior body 3 forms the outer wall of the secondary battery 1. The exterior body 3 has a substantially rectangular shape formed by side walls 35 (see FIGS. 3 to 5), a pair of first exterior body sides 31, and a pair of second exterior body sides 32. The exterior body 3 has a connection port 7 that communicates with the circulation circuit 10.

[0026] The side wall 35 is a rectangular plate-shaped member in plan view. The side wall 35 has a longitudinal direction in the D1 direction in plan view. The first exterior body side 31 stands up from the side wall 35 in plan view (when viewed from the D3 direction). The first exterior body side 31 is along the D1 direction which is the longitudinal direction of the secondary battery 1. The second exterior body side 32 stands up from the side wall 35 in the same direction as the first exterior body side 31 and is orthogonal to the first exterior body side 31. The four corners of the exterior body 3 formed by the first exterior body side 31 and the second exterior body side 32 are chamfered. The exterior body 3 is sealed by a lid body 36 (see FIGS. 3 to 5) from the side opposite to the side wall 35 in the D3 direction, and is configured such that the fluid filled inside the exterior body 3 does not leak. In FIG. 2, the lid body 36 is omitted for convenience of explanation.

[0027] The electrode laminate 4 is formed in plan view by a first electrode laminate side 43 facing a pair of first exterior body sides 31 and a second electrode laminate side 44 facing a pair of second exterior body sides 32, and has a substantially rectangular shape smaller than the exterior body 3. The electrode laminate 4 is a rectangular plate-shaped member in plan view.

[0028] The electrode laminate 4 is formed by sealing an electrode body 41 with a resin film 42. The electrode body 41 is composed of a positive electrode, a negative electrode, and an electrolyte layer disposed between the positive electrode and the negative electrode. The center of the electrode body 41 is located at the center of the resin film 42 in plan view.

[0029] The resin film 42 sandwiches the electrode body 41 toward the inside in the D3 direction. The resin film 42 is formed of an insulating resin having gas permeability (not containing metal). In the following description, the portion of the resin film 42 that sandwiches the electrode body 41 is referred to as the resin film main body portion 42A, and the portion surrounding the resin film main body portion 42A when viewed from the D1 direction is referred to as the resin film peripheral portion 42B.

[0030] As shown in FIGS. 3 and 4, the resin film main body 42A is provided without a gap between the side wall 35 and the lid 36. The outer surface of the resin film main body 42A forms a first electrode laminate side 43 along the D1 direction and a second electrode laminate side 44 along the D2 direction. The resin film peripheral portion 42B overlaps in the D3 direction without sandwiching the electrode body 41. The thickness of the resin film peripheral portion 42B in the D3 direction is thinner than the thickness of the resin film main body 42A in the D3 direction. As shown in FIGS. 3 to 5, the exterior body 3 and the electrode laminate 4 are provided spaced apart at positions corresponding to the resin film peripheral portion 42B. The space provided between the resin film peripheral portion 42B, the side wall 35, and the lid 36 is filled with a fluid.

[0031] A first cooling channel 51 is provided between the first exterior body side 31 and the first electrode laminate side 43. Specifically, the first cooling channel 51 is a portion surrounded by the first exterior body side 31, the first electrode laminate side 43, the side wall 35, and the lid 36.

[0032] A second cooling channel 52 is provided between the second exterior body side 32 and the second electrode laminate side 44. Specifically, the second cooling channel 52 is a portion surrounded by the second exterior body side 32, the second electrode laminate side 44, the side wall 35, and the lid 36.

[0033] As shown in FIG. 2, in a plan view, the first width H1 from the first exterior body side 31 to the first electrode laminate side 43 is narrower than the second width H2 from the second exterior body side 32 to the second electrode laminate side 44. As shown in FIGS. 3 to 4, since the third width H3 from the side wall 35 to the lid 36 is uniform, the cross-sectional area of the D1-D2 cross-section of the first cooling channel 51 is smaller than the cross-sectional area of the D2-D3 cross-section of the second cooling channel 52. The region where the first cooling channel 51 and the second cooling channel 52 intersect has a third cooling channel 53. The third cooling channel 53 is located outside the four corners of the electrode laminate 4.

[0034] The connection port 7 has a first connection port 71 and a second connection port 72. The first connection port 71 and the second connection port 72 are provided on the first outer body side 31. The first connection port 71 and the second connection port 72 are provided at positions corresponding to the third cooling channel 53 on the first outer body side 31 respectively. The first connection port 71 and the second connection port 72 communicate with the third cooling channel 53 respectively.

[0035] The external terminal 11 protrudes from the second outer body side 32. The external terminal 11 has a positive terminal 12 and a negative terminal 13. As shown in FIG. 1, the cooling structure 100 of the secondary battery 1 includes a plurality of secondary batteries 1. The plurality of secondary batteries 1 are arranged adjacent to each other. The positive terminal 12 of the secondary battery 1 and the negative terminal 13 of the adjacent secondary battery 1 are electrically connected by an internal bus bar 14. The internal bus bar 14 is connected to the resin film 42 (resin film peripheral portion 42B). Also, the positive terminal 12 and the negative terminal 13 of the secondary battery 1 are electrically connected to an external device (not shown) by a harness (not shown). The space around the internal bus bar 14 is filled with a fluid.

[0036] In this embodiment, the positive terminal 12 is made of, for example, an aluminum alloy. Therefore, it has excellent thermal conductivity. In this embodiment, the negative terminal 13 is made of, for example, a copper alloy. Therefore, it has excellent thermal conductivity.

[0037] The plurality of secondary batteries 1 included in the power storage module pack 20 are connected by a refrigerant flow path 21. The plurality of secondary batteries 1 (unit cells) may have a structure sealed by a metal mold packaging material (not shown), but the structure of the power storage module pack 20 is not particularly limited.

[0038] [Function and Effect of the Cooling Structure 100 of the Secondary Battery 1] Hereinafter, the function of the cooling structure 100 of the secondary battery 1 will be described. When the secondary battery 1 starts charging and discharging, the secondary battery 1 generates heat and becomes hot, and gas is generated from the electrode body 41. The generated gas permeates through the resin film 42 and flows out into the space provided between the resin film 42 and the exterior body 3.

[0039] When the pump P of the circulation circuit 10 is driven, fluid flows into the secondary battery 1 at a high temperature toward the first connection port 71 of the secondary battery 1. The fluid flows into the first cooling channel 51 and the second cooling channel 52 from the third cooling channel 53. The flow rates of the fluid flowing into the first cooling channel 51 and the second cooling channel 52 are a fixed amount and the same amount. Since the cross-sectional area of the D1-D3 cross-section of the first cooling channel 51 is smaller than the cross-sectional area of the D2-D3 cross-section of the second cooling channel 52, the flow velocity v1 of the fluid flowing through the first cooling channel 51 is faster than the flow velocity v2 of the fluid flowing through the second cooling channel 52.

[0040] Heat exchange occurs between the secondary battery 1 and the fluid, whereby the secondary battery 1 is cooled. The fluid in the secondary battery 1 is discharged from the second connection port 72 to the gas-liquid separation tank ST.

[0041] Hereinafter, the effects of the cooling structure 100 of the secondary battery 1 will be described. In the configuration of the present embodiment, fluid circulates between the exterior body 3 and the electrode laminate 4. Therefore, it is possible to provide a cooling structure 100 for the secondary battery 1 that can quickly cool the secondary battery 1 while sufficiently removing the gas generated inside the secondary battery 1.

[0042] In the configuration of the present embodiment, the cross-sectional area of the D1-D3 cross-section of the first cooling channel 51 is smaller than the cross-sectional area of the D2-D3 cross-section of the second cooling channel 52. Therefore, by increasing the flow velocity v1 of the fluid flowing through the first cooling channel 51 and suppressing the flow velocity v2 of the fluid flowing through the second cooling channel 52, it is possible to equalize the flow rate distribution of the fluid and enhance the gas discharge performance of the fluid.

[0043] In the configuration of the present embodiment, the first connection port 71 and the second connection port 72 are respectively provided in the region (the third cooling channel 53) where the first cooling channel 51 and the second cooling channel 52 intersect, and each communicates with the third cooling channel 53. Therefore, by utilizing the flow velocity v1 of the fluid flowing through the first cooling channel 51, it is possible to more efficiently remove the gas staying in the region (the third cooling channel 53) where the first cooling channel 51 and the second cooling channel 52 intersect.

[0044] [Second Embodiment] Hereinafter, the second embodiment will be described. The difference between the first embodiment and the second embodiment is the position where the first connection port 71 and the second connection port 72 are provided. In the cooling structure 100 of the secondary battery 1 according to the second embodiment, the first connection port 71 and the second connection port 72 are provided at positions overlapping the first cooling channel 51. The first connection port 71 and the second connection port 72 communicate with the first cooling channel 51.

[0045] In the configuration of the second embodiment, the flow velocity v1 of the fluid flowing through the first cooling channel 51 can be increased. Therefore, by utilizing the flow velocity v1 of the fluid flowing through the first cooling channel 51, it is possible to more efficiently remove the gas staying in the region (the third cooling channel 53) where the first cooling channel 51 and the second cooling channel 52 intersect.

[0046] [Modification Example] In the present embodiment, although the configuration in which the first connection port 71 and the second connection port 72 are provided only on one of the pair of first outer body sides 31 has been described, it is not limited thereto. The first connection port 71 and the second connection port 72 may be provided on each of the pair of first outer body sides 31. Specifically, the first connection port 71 may be provided on one of the pair of first outer body sides 31, and the second connection port 72 may be provided on the other of the pair of first outer body sides 31.

[0047] The preferred embodiments of the present invention have been described above. However, the present invention is not limited to these, and additions, omissions, substitutions, and other changes to the configuration are possible without departing from the spirit of the present invention. It is also possible to appropriately combine the above-described modified examples.

Explanation of Reference Numerals

[0048] 1... secondary battery, 3... exterior body, 4... electrode laminate, 7... connection port, 10... circulation circuit, 31... first exterior body side, 32... second exterior body side, 42... resin film, 43... first electrode laminate side, 44... second electrode laminate side, 51... first cooling flow path, 52... second cooling flow path, 71... first connection port, 72... second connection port, 100... cooling structure

Claims

1. A circulation circuit for circulating a fluid, An exterior body having a connection port communicating with the circulation circuit, A flat electrode laminate housed in the exterior body and sealed with a resin film having gas permeability, provided with, The exterior body and the electrode laminate are provided separately from each other, The fluid flows between the exterior body and the electrode laminate, The connection port has a first connection port and a second connection port, The exterior body has a substantially rectangular shape formed by a pair of first exterior body sides and a pair of second exterior body sides orthogonal to the first exterior body sides in plan view, The first connection port and the second connection port are provided on the first exterior body side, In plan view, the electrode laminate is formed by a first electrode laminate side facing the pair of first exterior body sides and a second electrode laminate side facing the pair of second exterior body sides, and has a substantially rectangular shape smaller than the exterior body, A first cooling flow path is provided between the first exterior body side and the first electrode laminate side, A second cooling flow path is provided between the second exterior body side and the second electrode laminate side, A cooling structure for a secondary battery, characterized in that the cross-sectional area of the first cooling flow path is smaller than the cross-sectional area of the second cooling flow path.

2. The cooling structure for a secondary battery according to claim 1, characterized in that the first connection port and the second connection port are respectively provided in a region where the first cooling flow path and the second cooling flow path intersect.

3. The cooling structure for a secondary battery according to claim 1, characterized in that the first connection port and the second connection port are provided at positions overlapping the first cooling flow path.

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