Battery cell

Abstract

This battery cell (100A) comprises a battery element (110), a terminal (120) electrically connected to the battery element (110), and a flow path (160A) for cooling the terminal (120).

Description

Battery cell

[0001] The present invention relates to a battery cell.

[0002] In recent years, various types of battery cells have been developed. Each battery cell includes a battery element and a terminal electrically connected to the battery element.

[0003] Patent Document 1 describes a connecting conductor for storage batteries. The connecting conductor includes a connecting portion connected to each pole portion of two storage batteries and a heat dissipation rib provided on the connecting portion.

[0004] Patent Document 2 describes a secondary battery that includes an electrode coil, electrode terminals extending from the electrode coil, a laminate exterior that covers the electrode coil and the electrode terminals, and a coolant flow path that intersects with the electrode terminals.

[0005] Patent Document 3 describes a battery cell. The battery cell includes two battery elements and a passage-forming member positioned between the two battery elements. The passage-forming member defines a cooling air passage.

[0006] Patent Document 4 describes a vehicle power storage device, which includes a wound body and a heat pipe in contact with the wound body.

[0007] Japanese Utility Model Application Publication No. 5-6687 Japanese Patent Application Publication No. 2014-78471 Japanese Patent Application Publication No. 2006-351373 Japanese Patent Application Publication No. 2019-192381

[0008] In a battery cell, heat may be generated from the battery elements, and therefore it may be necessary to efficiently cool the battery cell.

[0009] One object of the present invention is to efficiently cool battery cells. Other objects of the present invention will become apparent from the description of this specification.

[0010] An aspect of the present invention is as follows: 1. A battery cell comprising: a battery element; a terminal electrically connected to the battery element; and a structure for cooling the terminal. 2. The battery cell according to 1., further comprising a thermal conductor thermally coupled to the battery element and the terminal. 3. The battery cell according to 2., in which the thermal conductor is located at least partially between a plurality of the battery elements. 4. The battery cell according to any one of 1. to 3., in which the structure has a flow path for flowing a coolant. 5. The battery cell according to any one of 1. to 4., in which the structure has a heat sink provided on the terminal. 6. The battery cell according to any one of 1. to 5., in which the structure is provided on a bus bar electrically connected to the terminal.

[0011] According to the above aspect of the present invention, the battery cells can be cooled efficiently.

[0012] 16 is a perspective view of a battery cell according to embodiment 1. FIG. 17 is a cross-sectional view of a first imaginary plane α shown in FIG. 1. FIG. 18 is a cross-sectional view of a second imaginary plane β shown in FIG. 1. FIG. 19 is a view showing a first modified example of FIG. 3. FIG. 20 is a view showing a second modified example of FIG. 3. FIG. 21 is a view showing a third modified example of FIG. 3. FIG. 22 is a perspective view of a terminal of a battery cell according to embodiment 2. FIG. 23 is a view showing a first modified example of FIG. 7. FIG. 24 is a view showing a second modified example of FIG. 7. FIG. 25 is a view showing a third modified example of FIG. 7. FIG. 26 is a view showing a fourth modified example of FIG. 7. FIG. 27 is a view showing a fifth modified example of FIG. 7. FIG. 28 is a perspective view of a terminal of a battery cell according to embodiment 3. FIG. 29 is a view showing a modified example of FIG. 13. FIG. 20 is a perspective view showing a portion of a plurality of battery cells according to embodiment 4. FIG. 21 is a perspective view showing a portion of a plurality of battery cells according to embodiment 5. FIG. 22 is a view showing a first modified example of FIG. 16. FIG. 23 is a view showing a second modified example of FIG. 16.

[0013] Hereinafter, embodiments and modifications of the present invention will be described with reference to the drawings. In all the drawings, similar components are designated by similar reference numerals, and descriptions thereof will be omitted as appropriate.

[0014] Fig. 1 is a perspective view of a battery cell 100A according to embodiment 1. Fig. 2 is a cross-sectional view of a first imaginary plane α shown in Fig. 1. Fig. 3 is a cross-sectional view of a second imaginary plane β shown in Fig. 1.

[0015] For the purpose of explanation, the X, Y, and Z directions are shown in each figure. The X direction indicates the front-rear direction of the battery cell 100A. The Y direction is perpendicular to the X direction. The Y direction indicates the left-right direction of the battery cell 100A. The Z direction is perpendicular to both the X and Y directions. The Z direction indicates the up-down direction of the battery cell 100A. The arrows pointing to the X direction, the Y direction, and the Z direction indicate the rear, right, and up directions of the battery cell 100A, respectively. In FIG. 2, the white circle with an X indicating the Y direction indicates that the arrow pointing to the Y direction extends from the front to the back of the page. In FIG. 3, the white circle with an X indicating the X direction indicates that the arrow pointing to the X direction extends from the front to the back of the page. The relationships between the X direction, Y direction, and Z direction and the front-rear direction, left-right direction, and up-down direction of the battery cell 100A are not limited to the example described in the first embodiment.

[0016] Hereinafter, as needed, the side indicated by the arrow indicating the X direction will be referred to as the +X side, and the side opposite the side indicated by the arrow indicating the X direction will be referred to as the -X side. Hereinafter, as needed, the side indicated by the arrow indicating the Y direction will be referred to as the +Y side, and the side opposite the side indicated by the arrow indicating the Y direction will be referred to as the -Y side. Hereinafter, as needed, the side indicated by the arrow indicating the Z direction will be referred to as the +Z side, and the side opposite the side indicated by the arrow indicating the Z direction will be referred to as the -Z side.

[0017] The first imaginary plane α shown in Figures 1 and 2 is a plane perpendicular to the Y direction at approximately the center in the Y direction of the battery cell 100A according to the first embodiment. For the sake of explanation, each battery element 110 shown in Figure 3 is illustrated by a dashed line in Figure 2. The second imaginary plane β shown in Figures 1 and 3 is a plane perpendicular to the X direction at approximately the center in the X direction of the battery cell 100A according to the first embodiment. For the sake of explanation, the dimensional ratio in the Y direction to the Z direction of the battery cell 100A shown in Figure 3 is larger than the dimensional ratio in the Y direction to the Z direction of the battery cell 100A shown in Figure 1. For the sake of explanation, the exterior film 150 shown in Figure 1 has been removed in Figures 2 and 3.

[0018] As shown in Figures 1 to 3, the battery cell 100A according to the first embodiment includes a plurality of battery elements 110, a pair of terminals 120, a thermal conductor 130, a pair of lid members 140, an exterior film 150, and a flow path 160A.

[0019] In the example shown in FIG. 3 , two battery elements 110 overlap each other in the Y direction. Each battery element 110 has a substantially rectangular parallelepiped shape. The dimension of each battery element 110 in the X direction is the dimension in the longitudinal direction of each battery element 110. The dimension of each battery element 110 in the Z direction is the dimension in the lateral direction of each battery element 110. The dimension of each battery element 110 in the Y direction is the dimension in the thickness direction of each battery element 110. The shape of each battery element 110 is not limited to this example.

[0020] As shown in FIG. 3 , each battery element 110 includes multiple positive electrodes 112, multiple negative electrodes 114, and separators 116. In each battery element 110, the multiple positive electrodes 112 and multiple negative electrodes 114 are alternately stacked in the Y direction. Each positive electrode 112 includes a positive electrode current collector (not shown) having a thickness in the Y direction and a positive electrode active material layer (not shown) located on both sides of the positive electrode current collector in the Y direction and having a thickness in the Y direction. The positive electrode current collector is, for example, aluminum foil having a thickness in the Y direction. Each negative electrode 114 includes a negative electrode current collector (not shown) having a thickness in the Y direction and a negative electrode active material layer (not shown) located on both sides of the negative electrode current collector in the Y direction and having a thickness in the Y direction. The negative electrode current collector is, for example, copper foil having a thickness in the Y direction. The area of ​​each negative electrode 114 perpendicular to the Y direction is larger than the area of ​​each positive electrode 112 perpendicular to the Y direction. In the example shown in FIG. 3 , the dimension of each negative electrode 114 in the Z direction is larger than the dimension of each positive electrode 112 in the Z direction. When viewed from the X direction, the separator 116 has a generally zigzag shape. Specifically, in the example shown in FIG. 3 , the separator 116 includes one folded portion covering the +Z side end of each positive electrode 112, the other folded portion covering the −Z side end of each negative electrode 114, and an extending portion extending from one folded portion to the other folded portion between the positive electrodes 112 and negative electrodes 114 adjacent to each other in the Y direction. The separator 116 may include one folded portion covering the −Z side end of each positive electrode 112, the other folded portion covering the +Z side end of each negative electrode 114, and an extending portion extending from one folded portion to the other folded portion between the positive electrodes 112 and negative electrodes 114 adjacent to each other in the Y direction.

[0021] As shown in FIG. 2 , a pair of terminals 120 are located on both sides of the battery element 110 in the X direction. Each terminal 120 is, for example, a conductive block such as a metal block or a conductive plate such as an embossed metal plate. One of the pair of terminals 120 and the multiple positive electrodes 112 of each battery element 110 are electrically connected to each other. For example, one of the pair of terminals 120 and the multiple positive electrodes 112 of each battery element 110 are electrically connected to each other via a positive electrode current collector (not shown in FIG. 2 ) that extends from each battery element 110 toward one of the pair of terminals 120. The other of the pair of terminals 120 and the multiple negative electrodes 114 of each battery element 110 are electrically connected to each other. For example, the other of the pair of terminals 120 and the multiple negative electrodes 114 of each battery element 110 are electrically connected to each other via a negative electrode current collector (not shown in FIG. 2 ) that extends from each battery element 110 toward the other of the pair of terminals 120. In one example, the −X side terminal 120 and the multiple positive electrodes 112 of each battery element 110 are electrically connected to each other, and the +X side terminal 120 and the multiple negative electrodes 114 of each battery element 110 are electrically connected to each other. Alternatively, the −X side terminal 120 and the multiple negative electrodes 114 of each battery element 110 may be electrically connected to each other, and the +X side terminal 120 and the multiple positive electrodes 112 of each battery element 110 may be electrically connected to each other.

[0022] As shown in FIG. 3 , the thermal conductor 130 is at least partially located between the two battery elements 110. The thermal conductor 130 is, for example, a conductive plate such as a metal plate. In the example shown in FIG. 2 , when viewed from the Y direction, the thermal conductor 130 has a substantially rectangular shape with a pair of long sides parallel to the X direction and a pair of short sides parallel to the Z direction. From the viewpoint of thermal conductivity of the thermal conductor 130, the dimension of the thermal conductor 130 in the Y direction is relatively large. For example, the dimension of the thermal conductor 130 in the Y direction is preferably equal to or greater than at least one of the dimension of the positive electrode current collector of the positive electrode 112 in the Y direction and the dimension of the negative electrode current collector of the negative electrode 114 in the Y direction. More preferably, the dimension of the thermal conductor 130 in the Y direction is greater than at least one of the dimension of the positive electrode current collector of the positive electrode 112 in the Y direction and the dimension of the negative electrode current collector of the negative electrode 114 in the Y direction. The dimension of the thermal conductor 130 in the Y direction is, for example, 0.1 μm or more and 2 mm or less. The larger the dimension of the thermal conductor 130 in the Y direction, the more efficiently it can cool the battery element 110. However, the shape of the thermal conductor 130 is not limited to the shape shown in FIG.

[0023] As shown in FIG. 2 , the +X side end of the −X side terminal 120 and the −X side end of the thermal conductor 130 are physically connected to each other. For example, the −X side terminal 120 and the thermal conductor 130 are integrated with each other. Therefore, the −X side terminal 120 and the thermal conductor 130 are thermally coupled to each other. The method for thermally coupling the −X side terminal 120 and the thermal conductor 130 to each other is not limited to this example. For example, the +X side end of the −X side terminal 120 and the −X side end of the thermal conductor 130 may be joined to each other via a thermally conductive adhesive.

[0024] The −X side terminal 120 and the thermal conductor 130 may be electrically connected to each other by a physical connection between the +X side end of the −X side terminal 120 and the −X side end of the thermal conductor 130. When the −X side terminal 120 and the thermal conductor 130 are electrically connected to each other, each positive electrode 112 or each negative electrode 114 of each battery element 110 may be electrically connected to the −X side terminal 120 via the thermal conductor 130. When the positive electrode 112 and the −X side terminal 120 are electrically connected to each other via the thermal conductor 130, it is preferable that the material of the positive electrode current collector of the positive electrode 112 and the material of the thermal conductor 130 are the same, from the viewpoint of matching the electrical characteristics, such as the electrical resistivity, of both the positive electrode current collector of the positive electrode 112 and the thermal conductor 130. When the negative electrode 114 and the −X side terminal 120 are electrically connected to each other via the thermal conductor 130, it is preferable that the material of the negative electrode current collector of the negative electrode 114 and the material of the thermal conductor 130 are the same, from the viewpoint of matching the electrical characteristics, such as the electrical resistivity, of both the negative electrode current collector of the negative electrode 114 and the thermal conductor 130. As shown in FIG. 2 , the −X side end of the +X side terminal 120 and the +X side end of the thermal conductor 130 are spaced apart from each other in the X direction. Therefore, the +X side terminal 120 and the thermal conductor 130 are electrically insulated from each other. Therefore, it is possible to prevent the +X side terminal 120 and the −X side terminal 120 from being short-circuited via the thermal conductor 130.

[0025] As shown in FIG. 3 , the −Y side surface of the negative electrode 114 located at the −Y side end of the +Y side battery element 110 and the +Y side surface of the thermal conductor 130 are in close proximity to or in contact with each other. Therefore, the +Y side battery element 110 and the thermal conductor 130 are thermally coupled to each other. The method of thermally coupling the +Y side battery element 110 and the thermal conductor 130 to each other is not limited to this example. For example, the −Y side surface of the negative electrode 114 located at the −Y side end of the +Y side battery element 110 and the +Y side surface of the thermal conductor 130 may be joined to each other via a thermally conductive adhesive.

[0026] As shown in FIG. 3 , the +Y-side surface of the negative electrode 114 located at the +Y-side end of the -Y-side battery element 110 and the -Y-side surface of the thermal conductor 130 are in close proximity to or in contact with each other. Therefore, the -Y-side battery element 110 and the thermal conductor 130 are thermally coupled to each other. The method for thermally coupling the -Y-side battery element 110 and the thermal conductor 130 to each other is not limited to this example. For example, the +Y-side surface of the negative electrode 114 located at the +Y-side end of the -Y-side battery element 110 and the -Y-side surface of the thermal conductor 130 may be joined to each other via a thermally conductive adhesive.

[0027] As shown in FIG. 2 , a pair of lid members 140 cover both end faces of the battery element 110 in the X direction. Each lid member 140 is, for example, a resin body. When viewed from the X direction, each lid member 140 has a substantially rectangular shape with a pair of short sides parallel to the Y direction and a pair of long sides parallel to the Z direction. The +X-side terminal 120 at least partially protrudes toward the +X side from the +X-side surface of the +X-side lid member 140 when the +X-side lid member 140 covers the +X-side end face of the battery element 110. The −X-side terminal 120 at least partially protrudes toward the −X side from the −X-side surface of the −X-side lid member 140 when the −X-side lid member 140 covers the −X-side end face of the battery element 110.

[0028] As shown in FIG. 1 , the exterior film 150 is wrapped around the battery element 110 and the pair of lid members 140 in the X direction. The outer peripheral surface around the X direction of the lid member 140 on the +X side and the inner peripheral surface around the X direction of the end of the +X side of the exterior film 150 are joined to each other by a joining method such as heat fusion. The outer peripheral surface around the X direction of the lid member 140 on the -X side and the inner peripheral surface around the X direction of the end of the -X side of the exterior film 150 are joined to each other by a joining method such as heat fusion. Portions of the exterior film 150 are joined to each other by a joining method such as heat fusion at least in part around the X direction of the battery element 110. Thus, the battery element 110 is sealed by the exterior film 150.

[0029] The battery cell 100A according to the first embodiment contains an electrolyte solution inside an area sealed by the exterior film 150. However, the battery cell 100A may be an all-solid-state battery. In an all-solid-state battery, a solid electrolyte layer is provided in a portion corresponding to the separator 116. An all-solid-state battery does not contain an electrolyte solution. Hereinafter, unless otherwise specified, the battery cell 100A will be described as a battery cell containing an electrolyte solution.

[0030] As shown in FIGS. 1 and 2 , when viewed from the X direction, the flow path 160A at least partially surrounds the -X-side thermal conductor 130 in the X direction. The flow path 160A is a flow path for flowing a refrigerant such as water. The terminal 120 and the flow path 160A are thermally coupled to each other. Thus, the flow path 160A is configured to cool the terminal 120 by flowing a refrigerant through the flow path 160A. As described above, the two battery elements 110 and the -X-side terminal 120 are thermally coupled to each other via the thermal conductor 130. Therefore, in the first embodiment, even if heat is generated from the battery elements 110 on both sides of the thermal conductor 130 in the Y direction, the -X-side terminal 120 is cooled by the refrigerant flowing through the flow path 160A, thereby efficiently cooling the battery cell 100A via the thermal conductor 130.

[0031] During charging and discharging of the battery cell 100A, current concentrates on the positive electrode 112, the negative electrode 114, or the positive or negative electrode current collector drawn from the battery element 110 toward the +X side terminal 120 or the −X side terminal 120 near the −X side terminal 120. Therefore, during charging and discharging of the battery cell 100A, heat is more likely to be generated at both ends of each battery element 110 in the X direction than at the approximate center of each battery element 110 in the X direction. In the first embodiment, even if current concentrates on the positive electrode 112, the negative electrode 114, or the positive or negative electrode current collector drawn from the battery element 110 toward the −X side terminal 120 near the −X side terminal 120, the −X side terminal 120 is cooled by the refrigerant flowing through the flow path 160A, thereby enabling efficient cooling of the battery cell 100A.

[0032] In the first embodiment, the dimensions of the -X side terminal 120 can be relatively large compared to when the -X side terminal 120 is simply a plate-shaped terminal perpendicular to the Y direction. For example, the Y direction dimension of the -X side terminal 120 may be larger than the Y direction dimension of the thermal conductor 130. As shown in FIG. 2 , the Z direction dimension of the -X side terminal 120 may be larger than the Z direction dimension of the thermal conductor 130. However, the Z direction dimension of the -X side terminal 120 may be equal to or smaller than the Z direction dimension of the thermal conductor 130. The larger the dimension of the -X side terminal 120, the more easily the refrigerant flowing through the flow path 160A can cool the thermal conductor 130 and the battery element 110 surrounding the thermal conductor 130 in the Y direction via the -X side terminal 120. Therefore, in the first embodiment, the battery cell 100A can be cooled more efficiently compared to when the -X side terminal 120 is simply a plate-shaped terminal perpendicular to the Y direction.

[0033] In the first embodiment, the −X side terminal 120 and the thermal conductor 130 are thermally coupled. However, the +X side terminal 120 and the thermal conductor 130 may also be thermally coupled to each other. When the +X side terminal 120 and the thermal conductor 130 are thermally coupled to each other, the flow path 160A may at least partially surround the +X side terminal 120 when viewed from the X direction. Even when the +X side terminal 120 and the thermal conductor 130 are thermally coupled to each other, the battery cell 100A can be efficiently cooled by cooling the +X side terminal 120 with the refrigerant flowing through the flow path 160A.

[0034] Fig. 4 is a diagram showing a first modified example of Fig. 3. The first modified example shown in Fig. 4 is similar to the first embodiment shown in Fig. 3 except for the following points.

[0035] As shown in FIG. 4 , three battery elements 110 may overlap one another in the Y direction. A thermal conductor 130 is at least partially located between adjacent battery elements 110 in the Y direction. The +Y-side thermal conductor 130 may be thermally coupled to one of the +X-side terminal 120 and the −X-side terminal 120, and the −Y-side thermal conductor 130 may be thermally coupled to the other of the +X-side terminal 120 and the −X-side terminal 120. In the first modified example shown in FIG. 4 , by cooling at least one of the +X-side terminal 120 and the −X-side terminal 120, each battery element 110 can be cooled on both sides of each thermal conductor 130 in the Y direction.

[0036] 3 and the first modified example shown in Fig. 4, the battery cell 100A may include four or more battery elements 110 stacked one on top of the other in the Y direction. When the battery cell 100A includes four or more battery elements 110, the thermal conductor 130 may be at least partially located between the battery elements 110 adjacent to each other in the Y direction.

[0037] Fig. 5 is a diagram showing a second modified example of Fig. 3. The second modified example shown in Fig. 5 is similar to the first embodiment shown in Fig. 3 except for the following points.

[0038] As shown in Fig. 5, each battery element 110 may include a plurality of separators 116. In each battery element 110, each separator 116 is located between a positive electrode 112 and a negative electrode 114 adjacent to each other in the Y direction. In the second modified example shown in Fig. 5, too, by cooling the terminal 120 on the +X side, each battery element 110 can be cooled on both sides of the thermal conductor 130 in the Y direction.

[0039] Fig. 6 is a diagram showing a third modified example of Fig. 3. The third modified example shown in Fig. 6 is similar to the second modified example shown in Fig. 5 except for the following points.

[0040] As shown in FIG. 6 , similar to the first modification shown in FIG. 4 , three battery elements 110 may be stacked one on top of the other in the Y direction. As shown in FIG. 6 , similar to the second modification shown in FIG. 5 , in each battery element 110, each of the multiple separators 116 is located between adjacent positive electrodes 112 and negative electrodes 114 in the Y direction. As shown in FIG. 6 , a thermal conductor 130 is at least partially located between adjacent battery elements 110 in the Y direction. The +Y-side thermal conductor 130 may be thermally coupled to one of the +X-side terminal 120 and the −X-side terminal 120, and the −Y-side thermal conductor 130 may be thermally coupled to the other of the +X-side terminal 120 and the −X-side terminal 120. In the third modification shown in FIG. 6 , by cooling at least one of the +X-side terminal 120 and the −X-side terminal 120, each battery element 110 can be cooled on both sides of each thermal conductor 130 in the Y direction.

[0041] Fig. 7 is a perspective view of the terminal 120 of the battery cell 100B according to embodiment 2. The battery cell 100B according to embodiment 2 is similar to the battery cell 100A according to embodiment 1 except for the following points: The terminal 120 shown in Fig. 7 is the terminal 120 located on the -X side of the battery cell 100B.

[0042] The battery cell 100B according to the second embodiment includes a flow path 160B. The flow path 160B is a flow path for flowing a coolant such as water. The flow path 160B passes at least partially through the interior of the terminal 120. Thus, the terminal 120 and the flow path 160B are thermally coupled to each other. In the example shown in FIG. 7 , as viewed from the X direction, the flow path 160B includes a pair of straight flow path portions 162B that pass through the interior of the +Y side portion of the terminal 120 and the interior of the −Y side portion of the terminal 120 in the Z direction, and a return flow path portion 164B that returns from one of the pair of straight flow path portions 162B to the other on the +Z side of the +Z side end face of the terminal 120. In the second embodiment, as in the first embodiment, the terminal 120 and the thermal conductor 130 (not shown in FIG. 7 ) are thermally coupled to each other. Therefore, in the second embodiment, as in the first embodiment, the terminal 120 is cooled by the refrigerant flowing through the flow path 160B, thereby efficiently cooling the battery cell 100B.

[0043] Fig. 8 is a diagram showing a first modified example of Fig. 7. The first modified example shown in Fig. 8 is similar to the second embodiment shown in Fig. 7 except for the following points.

[0044] As shown in Fig. 8 , when viewed from the X direction, the folded flow path portion 164B is folded back from one of the pair of straight flow path portions 162B to the other inside the end portion on the +Z side of the terminal 120. In the first modified example shown in Fig. 8 , as in the second embodiment shown in Fig. 7 , the terminal 120 is cooled by the refrigerant flowing through the flow path 160B, thereby efficiently cooling the battery cell 100B.

[0045] Fig. 9 is a diagram showing a second modified example of Fig. 7. The second modified example shown in Fig. 9 is similar to the second embodiment shown in Fig. 7 except for the following points.

[0046] As shown in Fig. 9 , when viewed from the Y direction, the pair of straight flow path portions 162B extend in the X direction, and when viewed from the Y direction, the turning flow path portion 164B turns back from one of the pair of straight flow path portions 162B to the other inside the terminal 120. In the second modified example shown in Fig. 9 , as in the second embodiment shown in Fig. 7 , the terminal 120 is cooled by the refrigerant flowing through the flow path 160B, thereby efficiently cooling the battery cell 100B.

[0047] Fig. 10 is a diagram showing a third modified example of Fig. 7. The third modified example shown in Fig. 10 is similar to the second embodiment shown in Fig. 7 except for the following points.

[0048] 10 , as viewed from the X direction, a pair of straight flow path portions 162B of +Z-side flow path 160B pass the +Z-side end of terminal 120 in the Y direction, and as viewed from the X direction, a turning flow path portion 164B of +Z-side flow path 160B is folded back from one of the pair of straight flow path portions 162B of +Z-side flow path 160B to the other on the -Y side with respect to the -Y side end face of terminal 120. As shown in FIG. 10 , as viewed from the X direction, a pair of straight flow path portions 162B of -Z-side flow path 160B pass the -Z-side end of terminal 120 in the Y direction, and as viewed from the X direction, a turning flow path portion 164B of -Z-side flow path 160B is folded back from one of the pair of straight flow path portions 162B of -Z-side flow path 160B to the other on the -Y side with respect to the -Y side end face of terminal 120. In the third modified example shown in Figure 10, as in embodiment 2 shown in Figure 7, the terminals 120 are cooled by the refrigerant flowing through each flow path 160B, thereby efficiently cooling the battery cell 100B.

[0049] Fig. 11 is a diagram showing a fourth modified example of Fig. 7. The fourth modified example shown in Fig. 11 is similar to the third modified example shown in Fig. 10 except for the following points.

[0050] As shown in Fig. 11 , when viewed from the X direction, the turning flow path portion 164B of the +Z side flow path 160B is turned back from one of the pair of straight flow path portions 162B of the +Z side flow path 160B to the other inside the terminal 120. As shown in Fig. 11 , when viewed from the X direction, the turning flow path portion 164B of the -Z side flow path 160B is turned back from one of the pair of straight flow path portions 162B of the -Z side flow path 160B to the other inside the terminal 120. In the fourth modified example shown in Fig. 11 , similar to the second embodiment shown in Fig. 7 , the terminal 120 is cooled by the refrigerant flowing through each flow path 160B, thereby efficiently cooling the battery cell 100B.

[0051] Fig. 12 is a diagram showing a fifth modified example of Fig. 7. The fifth modified example shown in Fig. 12 is similar to the third modified example shown in Fig. 10 except for the following points.

[0052] As shown in Fig. 12, when viewed from the X direction, flow path 160B may be alternately folded back between the +Y side with respect to the +Y side surface of terminal 120 and the -Y side with respect to the -Y side surface of terminal 120. Specifically, in the example shown in Fig. 12, folded back flow path portion 164B located on the -Y side with respect to the -Y side end face of the +Z side end of terminal 120 is folded back from the first straight flow path portion 162B from the +Z side to the second straight flow path portion 162B from the +Z side. Also, folded back flow path portion 164B located on the +Y side with respect to the +Y side end face of terminal 120 between the +Z side end and the -Z side end of terminal 120 is folded back from the second straight flow path portion 162B from the +Z side to the third straight flow path portion 162B from the +Z side. 7, the terminal 120 is cooled by the refrigerant flowing through the flow path 160B, and the battery cell 100B can be efficiently cooled by cooling the terminal 120 with the refrigerant flowing through the flow path 160B.

[0053] Fig. 13 is a perspective view of the terminal 120 of the battery cell 100C according to Embodiment 3. The battery cell 100C according to Embodiment 3 is similar to the battery cell 100A according to Embodiment 1 except for the following points: The terminal 120 shown in Fig. 13 is the terminal 120 located on the -X side of the battery cell 100C.

[0054] The terminal 120 according to the third embodiment has two heat sinks 160C. Each heat sink 160C is configured to cool the terminal 120. Specifically, the two heat sinks 160C are located on both sides of the approximate center of the terminal 120 in the Y direction. Therefore, the approximate center of the terminal 120 in the Y direction can be joined to a bus bar (not shown in FIG. 13 ) by a joining method such as laser welding. When viewed from the X direction, each heat sink 160C includes a plurality of fins 162C extending in the Z direction. In the second embodiment, similar to the first embodiment, the terminal 120 and the thermal conductor 130 (not shown in FIG. 13 ) are thermally coupled to each other. Therefore, in the third embodiment, similar to the first embodiment, the terminal 120 is cooled by each heat sink 160C, thereby efficiently cooling the battery cell 100C.

[0055] Fig. 14 is a diagram showing a modification of Fig. 13. The modification shown in Fig. 14 is similar to the third embodiment shown in Fig. 13 except for the following points.

[0056] As shown in Fig. 14 , two heat sinks 160C are located on either side of the approximate center of the terminal 120 in the Z direction. This allows the approximate center of the terminal 120 in the Z direction to be joined to a bus bar (not shown in Fig. 14 ) by a joining method such as laser welding. When viewed from the X direction, each heat sink 160C includes multiple fins 162C extending in the Y direction. In the modified example shown in Fig. 14 , the terminal 120 is cooled by each heat sink 160C, as in the third embodiment shown in Fig. 13 , and thus the battery cell 100C can be efficiently cooled.

[0057] 15 is a perspective view showing a portion of a plurality of battery cells 100D according to embodiment 4. The battery cell 100D according to embodiment 4 is similar to the battery cell 100B according to embodiment 2 except for the following points.

[0058] As shown in FIG. 15 , the plurality of battery cells 100D are provided with flow paths 160D. Similar to the flow path 160B according to the second embodiment, the flow path 160D according to the fourth embodiment is a flow path for flowing a coolant such as water. The flow path 160D passes at least partially through the interiors of the terminals 120 of the plurality of battery cells 100D. Therefore, the terminals 120 and the flow paths 160D are thermally coupled to each other. In the example shown in FIG. 15 , the flow path 160D includes four straight flow path portions 162D and three folded flow path portions 164D. The first straight flow path portion 162D from the +Z side and the second straight flow path portion 162D from the +Z side pass through the interiors of the +Z-side ends of the two terminals 120 of the two battery cells 100D adjacent in the Y direction in the Y direction. The third straight flow path portion 162D from the +Z side and the fourth straight flow path portion 162D from the +Z side pass in the Y direction inside the -Z-side ends of the two terminals 120 of two battery cells 100D adjacent in the Y direction. The first folded flow path portion 164D from the +Z side is folded back from the first straight flow path portion 162D from the +Z side to the second straight flow path portion 162D from the +Z side on the -Y side with respect to the -Y-side end face of the terminal 120 of the -Y-side battery cell 100D. The second folded flow path portion 164D from the +Z side is folded back from the second straight flow path portion 162D from the +Z side to the third straight flow path portion 162D from the +Z side on the +Y side with respect to the +Y-side end face of the terminal 120 of the +Y-side battery cell 100D. The third folded flow path portion 164D from the +Z side is folded back from the third straight flow path portion 162D from the +Z side to the fourth straight flow path portion 162D from the +Z side, on the -Y side with respect to the -Y side end face of the terminal 120 of the -Y side battery cell 100D. In the fourth embodiment, as in the first embodiment, the terminal 120 of each battery cell 100D and the thermal conductor 130 (not shown in FIG. 15 ) of each battery cell 100D are thermally coupled to each other. Therefore, in the fourth embodiment, as in the second embodiment, the terminal 120 of each battery cell 100D is cooled by the refrigerant flowing through the flow path 160D, thereby enabling efficient cooling of each battery cell 100D.

[0059] 16 is a perspective view showing a portion of a plurality of battery cells 100E according to embodiment 5. The battery cell 100E according to embodiment 5 is similar to the battery cell 100A according to embodiment 1 except for the following points.

[0060] A bus bar 200E is electrically connected to the terminals 120 of the battery cells 100E. The terminals 120 and the bus bar 200E are also thermally coupled to each other. In the example shown in Fig. 16, the terminals 120 on the -X side of two battery cells 100E adjacent in the Y direction are electrically connected to each other via the bus bar 200E. The bus bar 200E is located on the -X side of the terminals 120 of each battery cell 100E.

[0061] The bus bar 200E has flow paths 210E. The flow paths 210E are flow paths for flowing a refrigerant such as water. Therefore, the flow paths 210E are configured to cool the terminals 120 of each battery cell 100E. The flow paths 210E are located on the -X side of the bus bar 200E and extend in the Y direction at approximately the center of the bus bar 200E in the Z direction when viewed from the X direction. In the fourth embodiment, similar to the first embodiment, the terminals 120 of each battery cell 100E and the thermal conductors 130 (not shown in FIG. 16 ) of each battery cell 100E are thermally coupled to each other. Therefore, in the fifth embodiment, similar to the second embodiment, the terminals 120 of each battery cell 100E are cooled by the refrigerant flowing through the flow paths 210E, thereby efficiently cooling each battery cell 100E.

[0062] Fig. 17 is a diagram showing a first modified example of Fig. 16. The first modified example shown in Fig. 17 is similar to the fifth embodiment shown in Fig. 16 except for the following points.

[0063] As shown in FIG. 17 , two heat sinks 220E are located on either side of the approximate center of the bus bar 200E in the Z direction. Therefore, the approximate center of the bus bar 200E in the Z direction and the terminals 120 of each battery cell 100E can be joined to each other by a joining method such as laser welding. When viewed from the X direction, each heat sink 220E includes multiple fins 222E extending in the Y direction. Each heat sink 220E is configured to cool the terminals 120 of each battery cell 100E. Therefore, in the modified example shown in FIG. 17 , similar to the fifth embodiment shown in FIG. 16 , each battery cell 100E can be efficiently cooled by cooling each terminal 120 with each heat sink 220E.

[0064] Fig. 18 is a diagram showing a second modified example of Fig. 16. The second modified example shown in Fig. 18 is similar to the fifth embodiment shown in Fig. 16 except for the following points.

[0065] As shown in FIG. 18 , a heat sink 220E is located between the portions of the bus bar 200E that overlap with terminals 120 adjacent in the Y direction in the X direction. Therefore, the portions of the heat sink 220E that overlap with each terminal 120 in the X direction can be joined to each terminal 120 using a joining method such as laser welding. When viewed from the X direction, the heat sink 220E includes multiple fins 222E that extend in the Z direction. The heat sink 220E is configured to cool the terminals 120 of each battery cell 100E. Therefore, in the modified example shown in FIG. 18 , similar to the fifth embodiment shown in FIG. 16 , each battery cell 100E can be efficiently cooled by cooling each terminal 120 with the heat sink 220E.

[0066] Although the embodiments and modifications of the present invention have been described above with reference to the drawings, these are merely examples of the present invention, and various other configurations can also be adopted.

[0067] For example, in the first embodiment, the battery cell 100A includes a thermal conductor 130 thermally coupled to the battery element 110 and the terminal 120. However, the battery cell 100A does not necessarily need to include the thermal conductor 130. Even if the battery cell 100A does not include the thermal conductor 130, the battery cell 100A can be efficiently cooled by cooling the terminal 120, thereby cooling the area around the terminal 120. Furthermore, the terminal 120 and the positive electrode current collector or the negative electrode current collector drawn from the battery element 110 are connected to each other and thermally coupled to each other. Therefore, by cooling the terminal 120, the battery element 110 can be efficiently cooled via the positive electrode current collector or the negative electrode current collector. In particular, heat is more likely to be generated at both ends of the battery element 110 in the X direction than at the approximate center of the battery element 110 in the X direction. Therefore, the battery cell 100A can be efficiently cooled by cooling the terminal 120 located at at least one of the ends of the battery element 110 in the X direction. The same applies to the other embodiments and modifications.

[0068] This application claims priority based on Japanese Patent Application No. 2023-160057, filed September 25, 2023, the disclosure of which is incorporated herein by reference in its entirety.

[0069] 100A, 100B, 100C, 100D, 100E Battery cell, 110 Battery element, 112 Positive electrode, 114 Negative electrode, 116 Separator, 120 Terminal, 130 Thermal conductor, 140 Lid material, 150 Exterior film, 160A, 160B, 160D Flow path, 160C Heat sink, 162B, 162D Straight flow path portion, 162C Fin, 164B, 164D Turned flow path portion, 200E Bus bar, 210E Flow path, 220E Heat sink, 222E Fin

Claims

1. A battery cell comprising: a battery element; a terminal electrically connected to the battery element; and a structure for cooling the terminal.

2. The battery cell of claim 1, further comprising a thermal conductor thermally coupled to said battery element and said terminals.

3. The battery cell of claim 2, wherein the thermal conductor is located at least partially between a plurality of the battery elements.

4. A battery cell according to any one of claims 1 to 3, wherein the structure has a flow path for flowing a coolant.

5. A battery cell as claimed in any one of claims 1 to 4, wherein the structure includes a heat sink provided on the terminal.

6. The battery cell according to any one of claims 1 to 5, wherein the structure is provided on a bus bar electrically connected to the terminal.

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