Cooling structure of secondary battery

Abstract

The present invention provides a cooling structure for a secondary battery that can fully remove gas generated inside the secondary battery and quickly cool the secondary battery. The cooling structure for a secondary battery according to an embodiment of the present invention comprises a circulation circuit (10) for circulating a fluid; an outer body (3) having a connection port (7) communicating with the circulation circuit (10); and a flat-plate electrode stack (4) housed in the outer body (3) and sealed with a resin film, wherein the outer body (3) and the electrode stack (4) are separated and arranged, and the fluid flows between the outer body (3) and the electrode stack (4).

Description

Technical Field

[0001] The present invention relates to a cooling structure for a secondary battery. Background Art

[0002] In recent years, electric vehicles using electricity as a power source and hybrid vehicles using a combination of an engine and a motor for propulsion have attracted much attention, and various proposals have been made regarding battery modules to be installed in these vehicles.

[0003] For example, Japanese Patent Application Laid-Open No. 2007-273149 discloses a battery module (secondary battery) including a battery element exterior member composed of a laminate film having a structure in which two or more resin film layers are laminated.

[0004] The battery module described in Japanese Patent Application Laid-Open No. 2007-273149 includes an exterior body that houses a gas-permeable resin layer. The battery module discharges gas generated in a space through the resin layer to the outside through a safety valve mechanism. Summary of the Invention

[0005] In the battery module cooling structure described in Japanese Patent Application Laid-Open No. 2007-273149, gas may accumulate at corners within the exterior housing or between the interior wall and the resin layer, resulting in insufficient gas removal. Furthermore, insufficient gas removal can hinder the flow of fluids such as refrigerant, potentially delaying battery module cooling.

[0006] An object of the present invention is to provide a cooling structure for a secondary battery that can sufficiently remove gas generated inside the secondary battery and quickly cool the secondary battery.

[0007] The cooling structure of a secondary battery of the first embodiment of the present invention comprises: a circulation circuit that circulates a fluid; an outer casing having a connection port connected to the circulation circuit; and a flat electrode stack housed in the outer casing and sealed by a resin film, wherein the outer casing is separated from the electrode stack and the fluid flows between the outer casing and the electrode stack.

[0008] The second scheme may also be based on the cooling structure of the secondary battery of the above-mentioned first scheme, wherein the connection port has a first connection port and a second connection port, the outer casing has a generally quadrilateral shape formed by a pair of first outer casing sides and a pair of second outer casing sides orthogonal to the first outer casing sides when viewed from above, the first connection port and the second connection port are arranged on the first outer casing side, the electrode stack has a generally quadrilateral shape formed by a first electrode stack side opposite to the pair of first outer casing sides and a second electrode stack side opposite to the pair of second outer casing sides when viewed from above, and is smaller than the outer casing, a first cooling flow path is provided between the first outer casing side and the first electrode stack side, and a second cooling flow path is provided between the second outer casing side and the second electrode stack side, and the cross-sectional area of the first cooling flow path is smaller than the cross-sectional area of the second cooling flow path.

[0009] A third embodiment may be the cooling structure for the secondary battery according to the second embodiment, wherein the first connection port and the second connection port are respectively provided at a region where the first cooling flow path intersects the second cooling flow path.

[0010] A fourth aspect may be the cooling structure for a secondary battery according to the second aspect, wherein the first connection port and the second connection port are provided at positions overlapping with the first cooling flow path.

[0011] According to the first aspect, the fluid flows between the outer casing and the electrode stack, thereby providing a secondary battery cooling structure capable of sufficiently removing gas generated inside the secondary battery and rapidly cooling the secondary battery.

[0012] In the second embodiment, the cross-sectional area of the first cooling channel is smaller than that of the second cooling channel. This increases the flow rate of the fluid flowing through the first cooling channel while suppressing the flow rate of the fluid flowing through the second cooling channel. This evens out the flow distribution of the fluids and improves the discharge efficiency of gases generated in the fluids.

[0013] In the third embodiment, the first and second connecting ports are respectively provided at the intersection of the first and second cooling channels. Therefore, the flow rate of the fluid flowing through the first cooling channel can be utilized to more efficiently remove gas trapped in the intersection of the first and second cooling channels.

[0014] In the fourth embodiment, the first and second connection ports are positioned overlapping the first cooling channel. This allows for a higher velocity of the fluid flowing through the first cooling channel. Consequently, the velocity of the fluid flowing through the first cooling channel can be utilized to more efficiently remove gas trapped in the intersection of the first and second cooling channels. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is a flowchart schematically showing a cooling structure of a secondary battery according to an embodiment of the present invention.

[0016] Figure 2 This is a plan view schematically showing a secondary battery included in the cooling structure for a secondary battery according to an embodiment of the present invention.

[0017] Figure 3 yes Figure 2 Sectional view III-III.

[0018] Figure 4 yes Figure 2 IV-IV sectional view of FIG.

[0019] Figure 5 yes Figure 2 VV cross-sectional view of. DETAILED DESCRIPTION

[0020] The following describes embodiments of the present invention with reference to the accompanying drawings. The drawings used in the following description may sometimes show enlarged portions of features for ease of understanding, and the shapes, dimensional ratios, etc. of the components are not limited to those shown.

[0021] [First embodiment]

[0022] Figure 1 This is a flowchart schematically showing the cooling structure 100 of the secondary battery 1 according to the embodiment of the present invention.

[0023] like Figure 1 As shown, a cooling structure 100 for a secondary battery 1 includes a circulation circuit 10 for circulating a fluid, and a power storage module package 20 including a plurality of secondary batteries 1 .

[0024] A fluid, serving as a cooling medium (refrigerant), circulates through the circulation loop 10 and the battery module package 20. The fluid can be either a gas or a liquid. For example, the fluid can be an insulating liquid such as a fluorine-based inert liquid. Because the fluid is an insulating liquid, it can directly cool the internal busbar 14, described later, improving cooling performance.

[0025] The circulation circuit 10 includes a gas-liquid separation tank ST, a radiator RAD, a thermostatic valve SV (thermostatic valve), 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 included.

[0026] In the following description, when the fluid is flowing through the circulation circuit 10 , the direction in which the liquid flows out of the storage module package 20 is referred to as the “upstream side,” and the direction in which the fluid flows into the storage module package 20 is referred to as the “downstream side.”

[0027] The gas-liquid separator tank ST separates gas and liquid from the fluid flowing in from the electricity storage module package 20. The liquid separated by the gas-liquid separator tank ST circulates as fluid on the downstream side of the gas-liquid separator tank ST.

[0028] The upstream side of the gas-liquid separation tank ST is connected to the power storage module package 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 thermostatic valve SV.

[0029] 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 thermostatic valve SV.

[0030] The thermostatic valve SV is a three-way valve that switches according to the temperature of the fluid. The downstream side of the thermostatic valve SV is connected to the upstream side of the pump P.

[0031] The pump P supplies the fluid to the circulation circuit 10 via the storage module package 20 in response to a requested output from the storage module package 20. The downstream side of the pump P is connected to the upstream side of the heater H.

[0032] The heater H has a function of adjusting the temperature of the fluid. The downstream side of the heater H is connected to the storage module package 20. When the heater H is not provided, the downstream side of the pump P is connected to the storage module package 20.

[0033] Figure 2 1 is a plan view schematically showing the secondary battery 1 provided with the cooling structure 100 of the secondary battery 1 according to the embodiment of the present invention. Figure 3 yes Figure 2 Sectional view III-III. Figure 4 yes Figure 2 IV-IV sectional view of FIG. Figure 5 yes Figure 2 VV cross-sectional view of.

[0034] The secondary battery 1 is a rectangular plate-shaped member in a plan view and is, for example, a pouch-type lithium-ion secondary battery.

[0035] Figures 2 to 5 In FIG. 1 , direction D1 indicates the length direction of the secondary battery 1 in a plan view. Direction D2 indicates the width direction of the secondary battery 1 in a plan view. Direction D3 indicates the depth direction of the secondary battery 1 in a plan view.

[0036] like Figures 2 to 5As shown, the secondary battery 1 includes an exterior body 3 , a flat-plate-shaped electrode stack 4 housed in the exterior body 3 , and an external terminal 11 .

[0037] The outer casing 3 forms the outer wall of the secondary battery 1. The outer casing 3 has a side wall 35 (see Figures 3 to 5 ), a pair of first outer body sides 31 and a pair of second outer body sides 32 formed into a substantially quadrilateral shape. The outer body 3 has a connection port 7 that communicates with the circulation circuit 10.

[0038] The side wall 35 is a rectangular plate-shaped member in a plan view. The side wall 35 has a longitudinal direction in the D1 direction in a plan view.

[0039] The first exterior body side 31 stands upright from the side wall 35 in a plan view (as viewed from the direction D3 ).

[0040] The first outer casing side 31 extends along the longitudinal direction of the secondary battery 1 , that is, along the direction D1 .

[0041] The second outer casing side 32 rises from the side wall 35 in the same direction as the first outer casing side 31 and is perpendicular to the first outer casing side 31 .

[0042] The four corners of the exterior body 3 formed by the first exterior body side 31 and the second exterior body side 32 are rounded.

[0043] The outer body 3 is formed by the cover 36 (see Figures 3 to 5 ) is sealed from the side opposite to the side wall 35 in the D3 direction, and the fluid filled in the interior of the outer body 3 does not leak out. Figure 2 In the figure, the cover 36 is omitted for convenience of description.

[0044] The electrode stack 4 has a generally quadrilateral shape, smaller than the exterior body 3, when viewed from above, formed by a first electrode stack side 43 opposing the pair of first exterior body sides 31 and a second electrode stack side 44 opposing the pair of second exterior body sides 32. The electrode stack 4 is a rectangular plate-like member when viewed from above.

[0045] The electrode stack 4 is formed by sealing an electrode body 41 with a resin film 42 .

[0046] 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 a plan view.

[0047] The resin film 42 sandwiches the electrode body 41 inward in the direction D3. The resin film 42 is formed of an insulating resin that is air-permeable (does not contain 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 portion 42A. When viewed from the direction D1, the portion of the resin film 42 surrounding the resin film main portion 42A is referred to as the resin film peripheral portion 42B.

[0048] The resin film main body 42A is as follows Figure 3 and Figure 4 As shown, the resin film main body 42A is provided without a gap between the side wall 35 and the cover 36. The outer side surface of the resin film main body 42A forms a first electrode stack side 43 along the D1 direction and a second electrode stack side 44 along the D2 direction.

[0049] The resin film peripheral portion 42B does not sandwich the electrode body 41 and overlaps in the D3 direction. The thickness of the resin film peripheral portion 42B in the D3 direction is thinner than the thickness of the resin film main body portion 42A in the D3 direction. Figures 3 to 5 As shown, the outer casing 3 and the electrode stack 4 are spaced apart at positions corresponding to the resin film peripheral portion 42B. The spaces between the resin film peripheral portion 42B and the side wall 35 and between the resin film peripheral portion 42B and the lid 36 are filled with a fluid.

[0050] A first cooling channel 51 is provided between the first exterior body side 31 and the first electrode stack side 43 . Specifically, the first cooling channel 51 is a portion surrounded by the first exterior body side 31 , the first electrode stack side 43 , the side wall 35 , and the lid 36 .

[0051] A second cooling channel 52 is provided between the second exterior package side 32 and the second electrode stack side 44 . Specifically, the second cooling channel 52 is a portion surrounded by the second exterior package side 32 , the second electrode stack side 44 , the side wall 35 , and the lid 36 .

[0052] like Figure 2 As shown, in a plan view, the first width H1 from the first outer casing side 31 to the first electrode stack side 43 is narrower than the second width H2 from the second outer casing side 32 to the second electrode stack side 44. Figures 3 and 4 As shown, the third width H3 from the side wall 35 to the cover 36 is the same, so the cross-sectional area of the D2 - D3 section of the first cooling flow path 51 is smaller than the cross-sectional area of the D1 - D3 section of the second cooling flow path 52 .

[0053] The third cooling channels 53 are provided in the region where the first cooling channels 51 and the second cooling channels 52 intersect. The third cooling channels 53 are located outside the four corners of the electrode stack 4 .

[0054] The connection port 7 includes 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 casing side 31. The first connection port 71 and the second connection port 72 are provided on the first outer casing side 31 at positions corresponding to the third cooling flow path 53. The first connection port 71 and the second connection port 72 are respectively connected to the third cooling flow path 53.

[0055] The external terminal 11 protrudes from the second outer casing side 32. The external terminal 11 includes a positive electrode terminal 12 and a negative electrode terminal 13.

[0056] like Figure 1 As shown, the cooling structure 100 for the secondary battery 1 includes a plurality of secondary batteries 1 .

[0057] A plurality of secondary batteries 1 are arranged adjacent to each other. A positive electrode terminal 12 of a secondary battery 1 and a negative electrode terminal 13 of an adjacent secondary battery 1 are electrically connected by an internal bus bar 14 .

[0058] Internal busbar 14 is connected to resin film 42 (resin film peripheral portion 42B). Positive electrode terminal 12 and negative electrode terminal 13 of secondary battery 1 are electrically connected to external equipment (not shown) via a wiring harness (not shown). The space around internal busbar 14 is filled with fluid.

[0059] In this embodiment, the positive electrode terminal 12 is made of, for example, an aluminum alloy. Therefore, it has excellent thermal conductivity. In this embodiment, the negative electrode terminal 13 is made of, for example, a copper alloy. Therefore, it has excellent thermal conductivity.

[0060] The plurality of secondary batteries 1 included in the power storage module package 20 are connected to each other via a coolant flow path 21. The plurality of secondary batteries 1 (unit cells) may be sealed by a metal mold package (not shown), and the structure of the power storage module package 20 is not particularly limited.

[0061] [Functions and Effects of Cooling Structure 100 for Secondary Battery 1]

[0062] Next, the function of the cooling structure 100 for the secondary battery 1 will be described.

[0063] When secondary battery 1 starts charging and discharging, secondary battery 1 generates heat to a high temperature, and gas is generated from electrode body 41. The generated gas permeates resin film 42 and flows into the space provided between resin film 42 and exterior body 3.

[0064] When pump P of circulation circuit 10 is driven, fluid flows toward first connection port 71 of secondary battery 1 relative to the high-temperature secondary battery 1. Fluid flows from third cooling channel 53 into first cooling channel 51 and second cooling channel 52. The flow rate of fluid flowing into first cooling channel 51 and second cooling channel 52 is constant and equal. The cross-sectional area of the D2-D3 section of first cooling channel 51 is smaller than the cross-sectional area of the D1-D3 section of second cooling channel 52. Therefore, the flow velocity v1 of the fluid flowing in first cooling channel 51 is faster than the flow velocity v2 of the fluid flowing in second cooling channel 52.

[0065] The secondary battery 1 is cooled by heat exchange between the secondary battery 1 and the fluid. The fluid in the secondary battery 1 is discharged from the second connection port 72 to the gas-liquid separator tank ST.

[0066] Next, the effects of the cooling structure 100 for the secondary battery 1 will be described.

[0067] In the structure of this embodiment, fluid flows between exterior body 3 and electrode stack 4. Therefore, it is possible to provide cooling structure 100 for secondary battery 1 that can sufficiently remove gas generated inside secondary battery 1 and quickly cool secondary battery 1.

[0068] In the structure of this embodiment, the cross-sectional area of the D2-D3 section of the first cooling channel 51 is smaller than the cross-sectional area of the D1-D3 section of the second cooling channel 52. Therefore, the flow velocity v1 of the fluid flowing through the first cooling channel 51 is increased, while the flow velocity v2 of the fluid flowing through the second cooling channel 52 is suppressed. This makes it possible to even out the flow distribution of the fluid and improve the discharge efficiency of gas generated in the fluid.

[0069] In the structure of this embodiment, the first connection port 71 and the second connection port 72 are respectively provided in the region (third cooling flow path 53) where the first cooling flow path 51 and the second cooling flow path 52 intersect, and are respectively connected to the third cooling flow path 53. Therefore, by utilizing the flow velocity v1 of the fluid flowing in the first cooling flow path 51, the gas accumulated in the region (third cooling flow path 53) where the first cooling flow path 51 and the second cooling flow path 52 intersect can be removed more efficiently.

[0070] [Second embodiment]

[0071] The second embodiment will be described below. The first embodiment differs from the second embodiment in the positions of the first connection port 71 and the second connection port 72 .

[0072] 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 with the first cooling flow path 51. The first connection port 71 and the second connection port 72 communicate with the first cooling flow path 51.

[0073] In the structure 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, the gas accumulated in the region (third cooling channel 53) where the first cooling channel 51 and the second cooling channel 52 intersect can be removed more efficiently.

[0074] [Modification]

[0075] In this embodiment, the first connection port 71 and the second connection port 72 are provided only on one of the pair of first exterior body sides 31, but the present invention is not limited thereto. The first connection port 71 and the second connection port 72 may also be provided on each of the pair of first exterior body sides 31. Specifically, the first connection port 71 may be provided on one of the pair of first exterior body sides 31, and the second connection port 72 may be provided on the other of the pair of first exterior body sides 31.

[0076] Preferred embodiments of the present invention have been described above, but the present invention is not limited thereto. Additions, omissions, substitutions, and other modifications of the structure can be made without departing from the spirit of the present invention, and the above-described modifications can be appropriately combined.

Claims

1. A cooling structure for a secondary battery, comprising: a circulation loop, which circulates a fluid; an outer body having a connection port communicating with the circulation circuit; and The flat plate-shaped electrode stack is housed in the outer casing and sealed with a gas-permeable resin film, wherein: The outer body is provided separately from the electrode stack. The fluid flows between the outer body and the electrode stack. The connection port includes a first connection port and a second connection port, The outer casing has a substantially quadrilateral shape formed by a pair of first outer casing sides and a pair of second outer casing sides perpendicular to the first outer casing sides in a plan view. The first connection port and the second connection port are provided on the side of the first outer body. The electrode stack has a generally quadrilateral shape smaller than the outer casings when viewed from above, formed by a first electrode stack side facing the pair of first outer casing sides and a second electrode stack side facing the pair of second outer casing sides. A first cooling channel is provided between the first outer casing side and the first electrode stack side. A second cooling channel is provided between the second outer casing side and the second electrode stack side. The first cooling channel and the second cooling channel form a substantially quadrilateral annular channel such that the intersection region is located outside the four corners of the substantially quadrilateral electrode stack. The cross-sectional area of the first cooling flow path is smaller than the cross-sectional area of the second cooling flow path, The fluid is discharged from the second connection port to the gas-liquid separation tank provided in the circulation circuit. The secondary battery cooling structure includes a plurality of secondary batteries. The plurality of secondary batteries are connected to each other via a coolant flow path.

2. The cooling structure for a secondary battery according to claim 1, wherein: The first connection port and the second connection port are respectively provided at a region where the first cooling flow path intersects the second cooling flow path.

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

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