Battery

Abstract

A battery (10) comprises an electrode body (14) provided with a positive electrode current collector and a negative electrode current collector, a case (12) that accommodates the electrode body (14), a first current collector terminal (20) that is joined to the positive electrode current collector, a second current collector terminal (22) that is joined to the negative electrode current collector, a first insulating member (24) that insulates the case (12) and the first current collector terminal (20) from each other, a first insulating member (24) that insulates the case (12) and the first current collector terminal (20) from each other, a second insulating member (26) that insulates the case (12) and the second collector terminal (22) from each other, a plurality of first external terminals (28) inserted into the case (12) and electrically connected to the first current collector terminal (20), and a second external terminal (30) inserted into the case (12) and electrically connected to the second current collector terminal (22).

Description

battery

[0001] The present disclosure relates to batteries.

[0002] Japanese Patent Laid-Open Publication No. 2023-61187 discloses a battery in which an electrode body is housed in a case. The battery disclosed in Japanese Patent Laid-Open Publication No. 2023-61187 has a positive electrode current collector terminal and a negative electrode current collector terminal provided in the case, the positive electrode current collector terminal being connected to the positive electrode of the electrode body via a plurality of positive electrode current collector tabs, and the negative electrode current collector terminal being connected to the negative electrode of the electrode body via a plurality of negative electrode current collector tabs.

[0003] However, in a structure in which one external terminal is provided on each of the positive and negative electrodes, such as the battery disclosed in JP 2023-61187 A, it is difficult to sufficiently dissipate the heat generated in the electrode body to the outside of the battery, and there is room for improvement in terms of improving heat dissipation performance.

[0004] In consideration of the above, the present disclosure aims to obtain a battery with improved heat dissipation performance.

[0005] a first insulating member provided between the case and the first current collecting terminal to insulate them from each other; a second insulating member provided between the case and the second current collecting terminal to insulate them from each other; a first external terminal that is inserted into the case and has one end exposed to the outside of the case and the other end electrically connected to the first current collecting terminal; and a second external terminal that is inserted into the case and has one end exposed to the outside of the case and the other end electrically connected to the second current collecting terminal, and at least one of the first external terminal and the second external terminal is provided in plurality.

[0006] In the battery according to the first aspect, an electrode assembly is housed in a case, and the electrode assembly includes a positive electrode current collector and a negative electrode current collector. A first current collector terminal and a second current collector terminal are provided inside the case, with the first current collector terminal joined to the positive electrode current collector and the second current collector terminal joined to the negative electrode current collector. A first insulating member is provided between the case and the first current collector terminal to insulate them, and a second insulating member is provided between the case and the second current collector terminal to insulate them. A first external terminal is inserted into the case, with one end of the first external terminal exposed to the outside of the case and the other end electrically connected to the first current collector terminal. A second external terminal is inserted into the case, with one end of the second external terminal exposed to the outside of the case and the other end electrically connected to the second current collector terminal. This allows power to be output from the battery to the outside.

[0007] In addition, at least one of the first external terminal and the second external terminal is provided in plurality, which increases the number of heat dissipation paths compared to a configuration in which one first external terminal and one second external terminal are provided, thereby enabling more heat generated in the electrode body to be dissipated.

[0008] In the battery of the second aspect, in the first aspect, the positive electrode current collector is joined to the first current collecting terminal on both sides of the first external terminal when viewed from the stacking direction of the electrode body, and the negative electrode current collector is joined to the second current collecting terminal on both sides of the second external terminal when viewed from the stacking direction of the electrode body.

[0009] In the battery according to the second aspect, the first external terminal is joined to the first current collecting terminals on both sides of the electrode assembly when viewed from the stacking direction, so that heat generated in the electrode assembly is dispersed and transferred to both sides of the first external terminal. Similarly, the second external terminal is joined to the second current collecting terminals on both sides of the electrode assembly when viewed from the stacking direction, so that heat generated in the electrode assembly is dispersed and transferred to both sides of the second external terminal. This makes it possible to suppress localized heat generation in the first current collecting terminal and the second current collecting terminal.

[0010] In the battery of the third aspect, in the first aspect, the electrode body has a longitudinal direction and a transverse direction when viewed from the stacking direction, and the first external terminal is provided at one longitudinal end of the electrode body, and the second external terminal is provided at the other longitudinal end of the electrode body.

[0011] In the battery according to the third aspect, the first external terminal is provided at one longitudinal end of the electrode body, and the second external terminal is provided at the other longitudinal end of the electrode body, so that heat can be dissipated from both longitudinal sides of the electrode body.

[0012] A fourth aspect of the present invention relates to the battery of the first aspect, wherein a plurality of the first external terminals and a plurality of the second external terminals are provided.

[0013] In the battery according to the fourth aspect, since a plurality of both the first external terminals and the second external terminals are provided, heat can be dissipated in a balanced manner from both the first external terminals and the second external terminals.

[0014] A fifth aspect of the battery is the fourth aspect, wherein the plurality of first external terminals are disposed adjacent to each other without sandwiching the positive electrode current collector therebetween, and the plurality of second external terminals are disposed adjacent to each other without sandwiching the negative electrode current collector therebetween.

[0015] In the battery according to the fifth aspect, the gap between adjacent first external terminals and the gap between adjacent second external terminals can be made smaller than in a configuration in which a positive electrode current collector is provided between adjacent first external terminals or a configuration in which a negative electrode current collector is provided between adjacent second external terminals, thereby enabling space saving.

[0016] In the battery of the sixth aspect, in the first aspect, the first external terminal is fixed with the first insulating member sandwiched between the case and the first collector terminal, and the second external terminal is fixed with the second insulating member sandwiched between the case and the second collector terminal.

[0017] In the battery according to the sixth aspect, the first external terminal is fixed between the case and the first current collector terminal with the first insulating member sandwiched therebetween, thereby preventing electrical conduction between the case and the first current collector terminal with a simple structure. Similarly, the second external terminal is fixed between the case and the second current collector terminal with the second insulating member sandwiched therebetween, thereby preventing electrical conduction between the case and the second current collector terminal with a simple structure.

[0018] A seventh aspect of the battery is the first aspect, wherein the first external terminal and the second external terminal are provided at positions opposite the widthwise center of the electrode body when viewed from the stacking direction of the electrode body.

[0019] In the battery according to the seventh aspect, heat can be effectively dissipated from the widthwise central portion of the electrode body, which is more likely to generate heat than the widthwise end portions.

[0020] In the battery of the eighth aspect, in the first aspect, the first external terminal is provided at a position opposite one widthwise end of the electrode body when viewed from the stacking direction of the electrode body, and the second external terminal is provided at a position opposite the other widthwise end of the electrode body when viewed from the stacking direction of the electrode body.

[0021] In the battery according to the eighth aspect, the first external terminal and the second external terminal are disposed diagonally when viewed from the stacking direction of the electrode assembly, thereby ensuring a long heat dissipation path and preventing heat from building up inside the case.

[0022] In the battery of the ninth aspect, in the first aspect, the first current collecting terminal and the second current collecting terminal are formed in an elongated shape along the width direction of the electrode body when viewed from the stacking direction of the electrode body, the positive electrode current collector is joined to the first current collecting terminal at a length that is at least half the length of the first current collecting terminal when viewed from the stacking direction of the electrode body, and the negative electrode current collector is joined to the second current collecting terminal at a length that is at least half the length of the second current collecting terminal when viewed from the stacking direction of the electrode body.

[0023] In the battery according to the ninth aspect, the positive electrode current collector is joined to the first current collecting terminal by at least half of its length, and the negative electrode current collector is joined to the second current collecting terminal by at least half of its length, which improves heat dissipation performance compared to a configuration in which the positive electrode current collector is joined to the first current collecting terminal by less than half of its length, or a configuration in which the negative electrode current collector is joined to the second current collecting terminal by less than half of its length.

[0024] A tenth aspect of the present invention relates to the battery of the first aspect, wherein the surface of the first current collector terminal facing the first insulating member and the surface of the second current collector terminal facing the second insulating member are formed in an uneven shape.

[0025] In the battery according to the tenth aspect, the surface of the first current collector terminal facing the first insulating member is formed unevenly, which prevents the first current collector terminal from slipping relative to the first insulating member and thereby breaking the insulating state. Similarly, the surface of the second current collector terminal facing the second insulating member is formed unevenly, which prevents the second current collector terminal from slipping relative to the second insulating member and thus breaking the insulating state.

[0026] As described above, the battery according to the present disclosure can improve heat dissipation performance.

[0027] FIG. 1 is a schematic cross-sectional view of a battery cell according to an embodiment. FIG. 2 is a cross-sectional view showing a state cut along line 2-2 in FIG. 1. FIG. 3 is an enlarged cross-sectional view showing a main part of FIG. 1. FIG. 4 is a cross-sectional view showing a state cut along line 4-4 in FIG. 3. FIG. 5 is a cross-sectional view illustrating a step of joining a positive electrode current collector to a first current collector terminal. FIG. 6 is a cross-sectional view showing a state in which a positive electrode current collector is joined to a first current collector terminal. FIG. 7 is a schematic cross-sectional view of a battery cell according to a first modified example. FIG. 8 is a schematic cross-sectional view of a battery cell according to a second modified example. FIG. 9 is a schematic cross-sectional view of a battery cell according to a third modified example.

[0028] 1 is a schematic cross-sectional view of a battery cell 10 according to an embodiment. For example, the battery cell 10 of this embodiment constitutes a battery pack mounted under the floor of an electric vehicle, and is configured to store electric power to be supplied to a drive motor (not shown).

[0029] The battery cell 10 of this embodiment can be widely applied to vehicles that use power supplied from a secondary battery as at least part of their driving source, such as hybrid vehicles (HVs) and plug-in hybrid electric vehicles (PHEVs), in addition to battery electric vehicles (BEVs).

[0030] The battery cell 10 according to the embodiment includes a case 12 and an electrode assembly 14. The case 12 forms the outer shell of the battery cell 10 and is formed in a substantially rectangular parallelepiped shape. As an example, the case 12 according to the embodiment includes a substantially cylindrical peripheral wall portion 12A, a positive electrode side cover portion 12B that closes an opening on one side of the peripheral wall portion 12A, and a negative electrode side cover portion 12C that closes an opening on the other side of the peripheral wall portion 12A.

[0031] The peripheral wall portion 12A is formed of metal in a generally rectangular cylindrical shape with both ends open, and is sized to accommodate the electrode assembly 14. The positive electrode side lid portion 12B is a metal member that is fixed to one opening of the peripheral wall portion 12A by fitting, welding, or other means, and closes the opening on one side of the peripheral wall portion 12A. The negative electrode side lid portion 12C is a metal member that is fixed to the other opening of the peripheral wall portion 12A by fitting, welding, or other means, and closes the opening on the other side of the peripheral wall portion 12A.

[0032] 2 is a cross-sectional view taken along line 2-2 in FIG. 1. As shown in FIG. 2, the electrode assembly 14 includes a positive electrode current collector 40 and a negative electrode current collector 48. Specifically, the electrode assembly 14 is configured by stacking the positive electrode current collector 40, a positive electrode composite 42, a solid electrolyte 44, a negative electrode composite 46, and a negative electrode current collector 48 in this order. For ease of explanation, FIG. 2 illustrates two layers of positive electrode current collectors 40 and one layer of negative electrode current collector 48, but in reality, many more positive electrode current collectors 40 and negative electrode current collectors 48 are stacked.

[0033] The negative electrode current collector 48 is disposed at the center in the stacking direction and is made of metal foil, for example, copper foil.

[0034] A negative electrode composite 46 is applied to both surfaces of the negative electrode current collector 48. The negative electrode composite 46 is a mixture of a negative electrode active material, a conductive additive, a binder, and the like. The negative electrode active material may be, for example, at least one selected from the group consisting of natural graphite, artificial graphite, hard carbon (non-graphitizable carbon), soft carbon (easily graphitizable carbon), Si, SiOx (0<x<2), Si-based alloys, Sn, SnOx (0<x<2), Li, Li-based alloys, and Li4Ti5O12. Examples of artificial graphite include highly oriented graphite and mesocarbon microbeads. Artificial graphite is preferred as the negative electrode active material.

[0035] A solid electrolyte 44 is laminated on the side of the negative electrode composite 46 opposite the negative electrode current collector 48. A positive electrode composite 42 is laminated on the side of the solid electrolyte 44 opposite the negative electrode composite 46. The positive electrode composite 42 is a mixture of a positive electrode active material, a conductive additive, a binder, and the like, and is applied to the positive electrode current collector 40. The positive electrode active material is not particularly limited, and conventionally known materials can be used as appropriate. Examples of positive electrode active materials include LiCoO2, LiNiO2, LiMnO2, LiMn2O4, Li(NiCoMn)O2, Li(NiCoAl)O2, and LiFePO4. The positive electrode active material particles may be Hi-Nickel (a positive electrode active material with a high Ni content), a Li-Ni-Co-Mn-based composite oxide, or a ternary positive electrode active material.

[0036] The positive electrode current collector 40 is formed of a metal foil, and aluminum foil is preferable as the positive electrode current collector 40. As such, as an example, the electrode body 14 of the present embodiment has a structure in which the negative electrode current collector 48 is arranged in the center in the stacking direction and the positive electrode current collectors 40 are arranged on both sides of this negative electrode current collector 48, so that the number of positive electrode current collectors 40 is greater than the number of negative electrode current collectors 48.

[0037] 1, the electrode body 14 has a longitudinal direction and a lateral direction when viewed from the stacking direction, and a positive electrode tab 16 extends from one longitudinal end of the electrode body 14, and a negative electrode tab 18 extends from the other longitudinal end. In the following description, the lateral direction of the electrode body 14 may be referred to as the width direction.

[0038] The positive electrode tab 16 is formed by collecting positive electrode foils extending from multiple positive electrode current collectors 40 that make up the electrode body 14, and in this embodiment, as an example, it is divided into three: a first positive electrode tab 16A, a second positive electrode tab 16B, and a third positive electrode tab 16C.

[0039] The first positive electrode tab 16A extends from a corner on one widthwise end side (upper right side on the paper) of the electrode body 14 toward the positive electrode side lid portion 12B side and is joined to a first current collecting terminal 20 described later. The second positive electrode tab 16B extends from the widthwise center part of the electrode body 14 toward the positive electrode side lid portion 12B side and is joined to a first current collecting terminal 20 described later. The third positive electrode tab 16C extends from a corner on the other widthwise end side (lower right side on the paper) of the electrode body 14 toward the positive electrode side lid portion 12B side and is joined to a first current collecting terminal 20 described later.

[0040] On the other hand, the negative electrode tab 18 is formed by collecting negative electrode foils extending from a plurality of negative electrode current collectors 48 that constitute the electrode body 14, and in the present embodiment, as an example, it is divided into three: a first negative electrode tab 18A, a second negative electrode tab 18B, and a third negative electrode tab 18C.

[0041] The first negative electrode tab 18A extends from a corner on one widthwise end side (upper left side on the paper) of the electrode body 14 toward the negative electrode side lid portion 12C side and is joined to a second current collector terminal 22 described later. The second negative electrode tab 18B extends from the widthwise center part of the electrode body 14 toward the negative electrode side lid portion 12C side and is joined to a second current collector terminal 22 described later. The third negative electrode tab 18C extends from a corner on the other widthwise end side (lower left side on the paper) of the electrode body 14 toward the negative electrode side lid portion 12C side and is joined to a second current collector terminal 22 described later.

[0042] The first current collecting terminal 20 is an elongated metal member provided inside the case 12 and extending along the width direction of the electrode body 14. Specifically, the first current collecting terminal 20 is attached to the positive electrode side lid portion 12B of the case 12 with a first insulating member 24 sandwiched therebetween, and extends from one end to the other end of the positive electrode side lid portion 12B. The first insulating member 24 is formed of an insulating material, and the case 12 and the first current collecting terminal 20 are insulated by this first insulating member 24.

[0043] The second current collecting terminal 22 is an elongated metal member provided inside the case 12 and extending along the width direction of the electrode body 14. Specifically, the second current collecting terminal 22 is attached to the negative electrode side lid portion 12C of the case 12 with a second insulating member 26 sandwiched therebetween, and extends from one end to the other end of the negative electrode side lid portion 12C. The second insulating member 26 is formed of an insulating material, and this second insulating member 26 insulates the case 12 and the second current collecting terminal 22.

[0044] Here, a plurality of first external terminals 28 are provided on the positive electrode side lid portion 12B of the case 12, and a plurality of second external terminals 30 are provided on the negative electrode side lid portion 12C. In the present embodiment, as an example, two first external terminals 28 and two second external terminals 30 are provided.

[0045] The first external terminal 28 is provided at a position that divides the positive electrode side lid portion 12B into approximately three equal parts, and the second external terminal 30 is provided at a position that divides the negative electrode side lid portion 12C into approximately three equal parts. Therefore, in the present embodiment, as an example, the first external terminal 28 and the second external terminal 30 are provided at positions that face each other. Details of the first external terminal 28 will be described below, but the second external terminal 30 has a similar configuration.

[0046] Fig. 3 is an enlarged cross-sectional view showing a main portion of Fig. 1. As shown in Fig. 3, the first external terminal 28 includes a shaft portion 28A, an outer flange portion 28B, and an inner flange portion 28C. The shaft portion 28A extends along the longitudinal direction of the electrode body 14 and is inserted into the positive electrode side lid portion 12B of the case 12.

[0047] The external flange portion 28B has a larger diameter than the shaft portion 28A and is located outside the positive electrode side cover portion 12B. The internal flange portion 28C has a larger diameter than the shaft portion 28A and is located inside the case 12. Therefore, one end of the first external terminal 28 is exposed to the outside of the case 12.

[0048] A resin part 32 is interposed between the first external terminal 28 and the positive electrode side lid part 12B. The resin part 32 is provided on the wall and edge of the insertion hole formed in the positive electrode side lid part 12B, and further covers the peripheral surface of the external flange part 28B of the first external terminal 28. Therefore, the resin part 32 insulates the first external terminal 28 from the positive electrode side lid part 12B.

[0049] The internal flange portion 28C of the first external terminal 28 bites into the first current collector terminal 20, and the first current collector terminal 20, the first insulating member 24, and the positive electrode side lid portion 12B are sandwiched by the first external terminal 28. That is, the first external terminal 28 is fixed in a state in which the first insulating member 24 is sandwiched between the case 12 and the first current collector terminal 20. Note that the first external terminal 28 of this embodiment is made of a crimping member, and is formed by crushing and crimping the external flange portion 28B and the internal flange portion 28C while the first external terminal 28 is inserted into the positive electrode side lid portion 12B.

[0050] Furthermore, since the first external terminal 28 is electrically connected to the first collector terminal 20, the first positive electrode tab 16A, the second positive electrode tab 16B, and the third positive electrode tab 16C of the electrode body 14 are electrically connected to the first external terminal 28 via this first collector terminal 20.

[0051] 1 , the second external terminal 30, like the first external terminal 28, is made of a crimping member and is formed by crimping the second external terminal 30 while it is inserted into the negative electrode side lid portion 12C. That is, the second external terminal 30 is fixed with the second insulating member 26 sandwiched between the case 12 and the second current collector terminal 22. The second external terminal 30 is insulated from the negative electrode side lid portion 12C and is conductive with the second current collector terminal 22. Therefore, the first negative electrode tab 18A, the second negative electrode tab 18B, and the third negative electrode tab 18C of the electrode body 14 are electrically connected to the second external terminal 30 via the second current collector terminal 22.

[0052] Furthermore, the electrode body 14 of this embodiment is joined to the first current collector terminals 20 on both sides of the first external terminal 28 when viewed from the stacking direction, and is joined to the second current collector terminals 22 on both sides of the second external terminal 30. Specifically, the first positive electrode tab 16A and the second positive electrode tab 16B are arranged to sandwich one first external terminal 28, and the second positive electrode tab 16B and the third positive electrode tab 16C are arranged to sandwich the other first external terminal 28.

[0053] In addition, the first negative electrode tab 18A and the second negative electrode tab 18B are arranged on either side of one second external terminal 30, and the second negative electrode tab 18B and the third negative electrode tab 18C are arranged on either side of the other second external terminal 30.

[0054] In this embodiment, the length of the region where the first positive electrode tab 16A, the second positive electrode tab 16B, and the third positive electrode tab 16C are joined to the first current collector terminal 20 is at least half the length of the first current collector terminal 20 when viewed from the stacking direction of the electrode body 14. Specifically, the positive electrode tab 16 and the first current collector terminal 20 are joined in most of the region except for the portion where the first external terminal 28 is provided.

[0055] Furthermore, the length of the region where the first negative electrode tab 18A, the second negative electrode tab 18B, and the third negative electrode tab 18C are joined to the second current collector terminal 22 is at least half the length of the second current collector terminal 22 when viewed from the stacking direction of the electrode body 14. Specifically, the negative electrode tab 18 and the second current collector terminal 22 are joined in most of the region except for the portion where the second external terminal 30 is provided.

[0056] Fig. 4 is a cross-sectional view taken along line 4-4 in Fig. 3. As shown in Fig. 4, the positive electrode tab 16 is joined to the first current collector terminal 20 in a state in which the positive electrode foil is collected and folded. The process of joining the positive electrode tab 16 to the first current collector terminal 20 will be described below with reference to Figs. 5 and 6.

[0057] Fig. 5 is a cross-sectional view illustrating a step of joining the positive electrode tab 16 of the positive electrode current collector to the first current collector terminal 20, and Fig. 6 is a cross-sectional view showing the state in which the positive electrode tab 16 has been joined to the first current collector terminal 20. As shown in Fig. 5, the positive electrode tab 16 is bent and placed over the first current collector terminal 20, and an anvil 100 serving as a receiving jig is placed on one surface of the first current collector terminal 20.

[0058] An ultrasonic horn 102 is placed on the other surface of the first current collecting terminal 20, and ultrasonic waves are generated to vibrate the ultrasonic horn 102 while the ultrasonic horn 102 is pressed against the positive electrode tab 16, thereby joining the positive electrode tab 16 to the first current collecting terminal 20. At this time, the surface of the anvil 100 is formed unevenly, and protrusions are formed on the ultrasonic horn 102. Then, the protrusions of the ultrasonic horn 102 are pressed against the positive electrode tab 16 to perform ultrasonic joining.

[0059] As shown in Fig. 6 , when the positive electrode tab 16 is joined to the first current collector terminal 20, the surface of the first current collector terminal 20 facing the anvil 100 is uneven. Also, grooves are formed in the positive electrode tab 16 at the portions where the ultrasonic horn 102 is pressed. Note that the unevenness and grooves are exaggerated in Fig. 6 for ease of explanation.

[0060] 1, the first insulating member 24 is sandwiched between the first current collector terminal 20 and the positive electrode side lid portion 12B, so that the uneven surface of the first current collector terminal 20 comes into contact with the first insulating member 24. The second current collector terminal 22 is ultrasonically bonded in the same manner as the first current collector terminal 20, so that the surface of the second current collector terminal 22 facing the second insulating member 26 is uneven. (Function) Next, the function of the battery cell 10 according to this embodiment will be described.

[0061] In the battery cell 10 according to this embodiment, an electrode assembly 14 is housed in a case 12, and the electrode assembly 14 includes a positive electrode current collector 40 and a negative electrode current collector 48 (see FIG. 2 ). A first current collector terminal 20 and a second current collector terminal 22 are provided inside the case 12, with the first current collector terminal 20 joined to the positive electrode current collector 40 and the second current collector terminal 22 joined to the negative electrode current collector 48.

[0062] Furthermore, a first insulating member 24 is provided between the positive electrode side lid portion 12B (case 12) and the first current collecting terminal 20 to insulate them, and a second insulating member 26 is provided between the negative electrode side lid portion 12C (case 12) and the second current collecting terminal 22 to insulate them. Furthermore, a first external terminal 28 is inserted into the positive electrode side lid portion 12B, one end of this first external terminal 28 is exposed to the outside of the case 12, and the other end is electrically connected to the first current collecting terminal 20. Furthermore, a second external terminal 30 is inserted into the negative electrode side lid portion 12C, one end of this second external terminal 30 is exposed to the outside of the case 12, and the other end is electrically connected to the second current collecting terminal 22. This allows power to be output from the battery cell 10 to the outside.

[0063] Furthermore, a plurality of at least one of the first external terminals 28 and the second external terminals 30 are provided. This increases the number of heat dissipation paths compared to a configuration in which one first external terminal 28 and one second external terminal 30 are provided, and therefore more heat generated in the electrode body 14 can be dissipated. In particular, in this embodiment, a plurality of both the first external terminals 28 and the second external terminals 30 are provided, so heat can be dissipated in a balanced manner from both the first external terminals 28 and the second external terminals 30.

[0064] Furthermore, in the battery cell 10 of this embodiment, the positive electrode tabs 16 are joined to the first current collector terminals 20 on both sides of the first external terminal 28 when viewed in the stacking direction of the electrode body 14, so that heat generated in the electrode body 14 is dispersed and transferred to both sides of the first external terminal 28. Similarly, the negative electrode tabs 18 are joined to the second current collector terminals 22 on both sides of the second external terminal 30 when viewed in the stacking direction of the electrode body 14, so that heat generated in the electrode body 14 is dispersed and transferred to both sides of the second external terminal 30. This makes it possible to suppress localized heat generation in the first current collector terminal 20 and the second current collector terminal 22.

[0065] Furthermore, in the battery cell 10 of this embodiment, the positive electrode tab 16 is joined to more than half of the length of the first current collector terminal 20, and the negative electrode tab 18 is joined to more than half of the length of the second current collector terminal 22. This improves heat dissipation performance compared to a configuration in which the positive electrode tab 16 is joined to less than half of the length of the first current collector terminal 20, or a configuration in which the negative electrode tab 18 is joined to less than half of the length of the second current collector terminal 22.

[0066] Furthermore, in the battery cell 10 of this embodiment, the first external terminal 28 is provided at one longitudinal end of the electrode body 14, and the second external terminal 30 is provided at the other longitudinal end of the electrode body 14, so heat can be dissipated from both longitudinal sides of the electrode body 14. Furthermore, the distance between the first external terminal 28 and the second external terminal 30 is increased, so heat can be dispersed.

[0067] 3, the first external terminal 28 is fixed with the first insulating member 24 sandwiched between the case 12 and the first current collector terminal 20. This makes it possible to suppress electrical conduction between the case 12 and the first current collector terminal 20 with a simple structure. Similarly, the second external terminal 30 is fixed with the second insulating member 26 sandwiched between the case 12 and the second current collector terminal 22 with a simple structure making it possible to suppress electrical conduction between the case 12 and the second current collector terminal 22.

[0068] Furthermore, in this embodiment, as shown in Fig. 6, the surface of the first current collecting terminal 20 facing the first insulating member 24 is formed unevenly. Therefore, as shown in Fig. 1, when the first current collecting terminal 20 is assembled, it is possible to prevent the first current collecting terminal 20 from slipping relative to the first insulating member 24 and losing its insulating state. Similarly, since the surface of the second current collecting terminal 22 facing the second insulating member 26 is formed unevenly, it is possible to prevent the second current collecting terminal 22 from slipping relative to the second insulating member 26 and losing its insulating state.

[0069] In the above embodiment, the first external terminal 28 is provided at a position that divides the positive electrode side lid portion 12B into approximately three equal parts, and the second external terminal 30 is provided at a position that divides the negative electrode side lid portion 12C into approximately three equal parts, as shown in Fig. 1 . However, the present invention is not limited to this. For example, the number and positions of the first external terminals 28 and the number and positions of the second external terminals 30 may be changed, as in first to third modified examples shown in Figs. 7 to 9 .

[0070] (First Modification) Fig. 7 is a schematic cross-sectional view of a battery cell 50 according to a first modification. As shown in Fig. 7, the battery cell 50 of this modification has three first external terminals 28 and two second external terminals 30.

[0071] The three first external terminals 28 are provided at positions facing the widthwise center of the electrode body 14 when viewed from the stacking direction of the electrode body 14. Specifically, the first external terminals 28 are provided coaxially with the center line passing through the widthwise center of the electrode body 14. Furthermore, the other first external terminals 28 are provided on both sides of this central first external terminal 28 with a small gap between them.

[0072] In this modified example, the three first external terminals 28 are arranged with a small gap between them, and therefore no positive electrode tab is provided in the widthwise center of the electrode body 14. Specifically, the first positive electrode tab 16A extends from a corner on one widthwise end side (upper right side on the paper) of the electrode body 14 toward the positive electrode side lid 12B side and is joined to the first current collector terminal 20. Furthermore, the third positive electrode tab 16C extends from a corner on the other widthwise end side (lower right side on the paper) of the electrode body 14 toward the positive electrode side lid 12B side and is joined to the first current collector terminal 20.

[0073] Therefore, the three first external terminals 28 are disposed at positions between the first positive electrode tab 16A and the third positive electrode tab 16C.

[0074] On the other hand, the two second external terminals 30 are provided at positions facing the widthwise center of the electrode body 14 when viewed from the stacking direction of the electrode body 14. Specifically, the second external terminals 30 are provided on both sides of a center line passing through the widthwise center of the electrode body 14, and the two second external terminals 30 are arranged with a small gap between them.

[0075] In this modified example, the two second external terminals 30 are arranged with a small gap between them, and therefore no negative electrode tab is provided in the widthwise center of the electrode body 14. Specifically, the first negative electrode tab 18A extends from a corner on one widthwise end side (upper left side on the paper) of the electrode body 14 toward the negative electrode side lid portion 12C and is joined to the second current collector terminal 22. The third negative electrode tab 18C extends from a corner on the other widthwise end side (lower left side on the paper) of the electrode body 14 toward the negative electrode side lid portion 12C and is joined to the second current collector terminal 22.

[0076] In the battery cell 50 of this modification, no positive electrode tabs are provided between adjacent first external terminals 28, and no negative electrode tabs are provided between adjacent second external terminals 30. Therefore, compared to a configuration in which positive electrode tabs are provided between adjacent first external terminals 28 or a configuration in which negative electrode tabs are provided between adjacent second external terminals 30, the gaps between adjacent first external terminals 28 and the gaps between adjacent second external terminals 30 can be made smaller, thereby enabling space savings.

[0077] Furthermore, in the battery cell 50 of this modified example, the number of first external terminals 28 is greater than the number of second external terminals 30. Therefore, even if the positive electrode tab 16 generates a large amount of heat, such as when the number of foil collections in the positive electrode tab 16 is greater than the number of foil collections in the negative electrode tab 18, it is possible to suppress an increase in temperature on the positive electrode side.

[0078] (Second Modification) Fig. 8 is a schematic cross-sectional view of a battery cell 60 according to a second modification. As shown in Fig. 8, the battery cell 60 according to this modification includes two first external terminals 28 and two second external terminals 30, similar to the embodiment, but the positions of the first external terminals 28 and the second external terminals 30 are different.

[0079] The two first external terminals 28 are inserted through the positive electrode side lid portion 12B, and one of the first external terminals 28 is provided in a position on the positive electrode side lid portion 12B facing one widthwise end of the electrode body 14. The other first external terminal 28 is provided in a position on the positive electrode side lid portion 12B facing the other widthwise end of the electrode body 14.

[0080] The positive electrode tab 16 is disposed between the two first external terminals 28, and is formed to be wider than the first positive electrode tab 16A, the second positive electrode tab 16B, and the third positive electrode tab 16C of the embodiment. In this modified example, only one positive electrode tab 16 is provided.

[0081] The two second external terminals 30 are inserted through the negative electrode side lid portion 12C, and one second external terminal 30 is provided in a position on the negative electrode side lid portion 12C facing one widthwise end of the electrode body 14. The other second external terminal 30 is provided in a position on the negative electrode side lid portion 12C facing the other widthwise end of the electrode body 14.

[0082] The negative electrode tab 18 is disposed between the two second external terminals 30, and is formed to be wider than the first negative electrode tab 18A, the second negative electrode tab 18B, and the third negative electrode tab 18C of the embodiment. In addition, in this modified example, only one negative electrode tab 18 is provided.

[0083] In the battery cell 60 of this modified example, in the widthwise central portion of the electrode body 14 where the temperature is likely to rise, the positive electrode tab 16 is joined over a wide area to the first current collector terminal 20, and the negative electrode tab 18 is joined over a wide area to the second current collector terminal 22. This allows for effective heat dissipation.

[0084] 9 is a schematic cross-sectional view of a battery cell 70 according to a third modification. As shown in Fig. 9, the battery cell 70 according to this modification has three first external terminals 28 and two second external terminals 30, similar to the first modification, but the positions of the first external terminals 28 and the second external terminals 30 are different.

[0085] The three first external terminals 28 are inserted through the positive electrode side lid portion 12B and are provided adjacent to positions on the positive electrode side lid portion 12B that face one widthwise end of the electrode body 14. Therefore, no first external terminals 28 are provided at a position that faces the other widthwise end of the electrode body 14.

[0086] The positive electrode tab 16 extends from the other widthwise end of the electrode body 14 toward the positive electrode-side lid portion 12B side, and is joined to the first current collector terminal 20. The positive electrode tab 16 is formed to be wider than the first positive electrode tab 16A, the second positive electrode tab 16B, and the third positive electrode tab 16C of the embodiment, and only one positive electrode tab 16 is provided.

[0087] The two second external terminals 30 are inserted through the negative electrode side lid portion 12C and are provided adjacent to the negative electrode side lid portion 12C at positions facing the other widthwise end of the electrode body 14. Therefore, no second external terminals 30 are provided at a position facing one widthwise end of the electrode body 14.

[0088] The negative electrode tab 18 extends from one widthwise end of the electrode body 14 toward the negative electrode side lid portion 12C side, and is joined to the second current collecting terminal 22. The negative electrode tab 18 is formed wider than the first negative electrode tab 18A, the second negative electrode tab 18B, and the third negative electrode tab 18C of the embodiment, and only one negative electrode tab 18 is provided.

[0089] In the battery cell 70 of this modified example, the first external terminal 28 and the second external terminal 30 are arranged diagonally when viewed from the stacking direction of the electrode body 14. This ensures a long heat dissipation path and prevents heat from building up inside the case 12.

[0090] The battery cells 10, 50, 60, and 70 according to the embodiments and modifications have been described above, but are not limited thereto and can of course be embodied in various forms without departing from the spirit and scope of the present disclosure. For example, in the above embodiments and modifications, the first current collector terminal 20 and the positive electrode tab 16 are provided at one longitudinal end of the electrode body 14, and the second current collector terminal 22 and the negative electrode tab 18 are provided at the other longitudinal end. However, this is not limited thereto, and the first current collector terminal and the second current collector terminal may be provided at one longitudinal end of the electrode body 14. Furthermore, the first current collector terminal and the second current collector terminal may be provided at one lateral end of the electrode body 14.

[0091] Furthermore, in the above embodiment and modified examples, the first external terminal 28 and the second external terminal 30 are fixed by crimping, but this is not limited to this and other methods of fixation may also be used. The disclosure of Japanese Patent Application No. 2024-134645 is incorporated herein by reference in its entirety. All documents, patent applications, and technical standards described herein are incorporated herein by reference to the same extent as if each individual document, patent application, and technical standard were specifically and individually indicated to be incorporated by reference.

[0092] The following notes are provided regarding the above embodiment.

[0093] a first insulating member provided between the case and the first current collecting terminal to insulate them from each other; a second insulating member provided between the case and the second current collecting terminal to insulate them from each other; a first external terminal that is inserted into the case, one end side of which is exposed to the outside of the case, and the other end side of which is electrically connected to the first current collecting terminal; and a second external terminal that is inserted into the case, one end side of which is exposed to the outside of the case, and the other end side of which is electrically connected to the second current collecting terminal, wherein at least one of the first external terminal and the second external terminal is provided in plurality. (Supplementary Note 2) The battery according to Supplementary Note 1, wherein the positive electrode current collector is joined to the first current collecting terminal on both sides of the first external terminal when viewed from the stacking direction of the electrode body, and the negative electrode current collector is joined to the second current collecting terminal on both sides of the second external terminal when viewed from the stacking direction of the electrode body. (Supplementary Note 3) The battery according to Supplementary Note 1 or Supplementary Note 2, wherein the electrode body has a longitudinal direction and a lateral direction when viewed from the stacking direction, and the first external terminal is provided at one longitudinal end of the electrode body, and the second external terminal is provided at the other longitudinal end of the electrode body. (Supplementary Note 4) The battery according to any one of Supplementary Notes 1 to 3, wherein a plurality of the first external terminals and a plurality of the second external terminals are provided. (Supplementary Note 5) The battery according to Supplementary Note 4, wherein a plurality of the first external terminals are provided adjacent to each other without the positive electrode current collector therebetween, and a plurality of the second external terminals are provided adjacent to each other without the negative electrode current collector therebetween. (Appendix 6) The battery according to any one of appendices 1 to 5, wherein the first external terminal is fixed with the first insulating member sandwiched between the case and the first current collector terminal, and the second external terminal is fixed with the second insulating member sandwiched between the case and the second current collector terminal.(Supplementary Note 7) The battery according to any one of Supplementary Notes 1 to 6, wherein the first external terminal and the second external terminal are provided at positions facing a widthwise center portion of the electrode body when viewed from the stacking direction of the electrode body. (Supplementary Note 8) The battery according to any one of Supplementary Notes 1 to 6, wherein the first external terminal is provided at a position facing one widthwise end portion of the electrode body when viewed from the stacking direction of the electrode body, and the second external terminal is provided at a position facing the other widthwise end portion of the electrode body when viewed from the stacking direction of the electrode body. (Supplementary Note 9) The battery according to any one of Supplementary Notes 1 to 8, wherein the first current collecting terminal and the second current collecting terminal are formed in an elongated shape along the width direction of the electrode body as viewed in the stacking direction of the electrode body, the positive electrode current collector is joined to the first current collecting terminal at a length that is at least half of the first current collecting terminal as viewed in the stacking direction of the electrode body, and the negative electrode current collector is joined to the second current collecting terminal at a length that is at least half of the second current collecting terminal as viewed in the stacking direction of the electrode body. (Supplementary Note 10) The battery according to any one of Supplementary Notes 1 to 9, wherein a surface of the first current collecting terminal facing the first insulating member and a surface of the second current collecting terminal facing the second insulating member are formed unevenly.

Claims

a first current collecting terminal provided inside the case and joined to the positive current collector; a second current collecting terminal provided inside the case and joined to the negative current collector; a first insulating member provided between the case and the first current collecting terminal to insulate them from each other; a second insulating member provided between the case and the second current collecting terminal to insulate them from each other; a first external terminal that is inserted into the case and has one end exposed to the outside of the case and the other end electrically connected to the first current collecting terminal; and a second external terminal that is inserted into the case and has one end exposed to the outside of the case and the other end electrically connected to the second current collecting terminal, wherein at least one of the first external terminal and the second external terminal is provided in plurality.

2. The battery described in claim 1, wherein the positive electrode current collector is joined to the first current collecting terminal on both sides of the first external terminal when viewed from the stacking direction of the electrode body, and the negative electrode current collector is joined to the second current collecting terminal on both sides of the second external terminal when viewed from the stacking direction of the electrode body.

3. A battery as described in claim 1, wherein the electrode body has a longitudinal direction and a lateral direction when viewed from the stacking direction, the first external terminal is provided at one longitudinal end of the electrode body, and the second external terminal is provided at the other longitudinal end of the electrode body.

4. The battery according to claim 1, wherein a plurality of the first external terminals and a plurality of the second external terminals are provided.

5. The battery according to claim 4, wherein the plurality of first external terminals are adjacently disposed without sandwiching the positive electrode current collector therebetween, and the plurality of second external terminals are adjacently disposed without sandwiching the negative electrode current collector therebetween.

6. The battery described in claim 1, wherein the first external terminal is fixed with the first insulating member sandwiched between the case and the first current collecting terminal, and the second external terminal is fixed with the second insulating member sandwiched between the case and the second current collecting terminal.

7. The battery according to claim 1, wherein the first external terminal and the second external terminal are provided at positions facing the widthwise center of the electrode body when viewed from the stacking direction of the electrode body.

8. A battery as described in claim 1, wherein the first external terminal is provided at a position facing one end of the electrode body in the width direction when viewed from the stacking direction of the electrode body, and the second external terminal is provided at a position facing the other end of the electrode body in the width direction when viewed from the stacking direction of the electrode body.

9. The battery described in claim 1, wherein the first current collecting terminal and the second current collecting terminal are formed in an elongated shape along the width direction of the electrode body when viewed from the stacking direction of the electrode body, the positive electrode current collector is joined to the first current collecting terminal at a length that is at least half the length of the first current collecting terminal when viewed from the stacking direction of the electrode body, and the negative electrode current collector is joined to the second current collecting terminal at a length that is at least half the length of the second current collecting terminal when viewed from the stacking direction of the electrode body.

10. The battery according to claim 1, wherein the surface of the first current collecting terminal facing the first insulating member and the surface of the second current collecting terminal facing the second insulating member are formed unevenly.

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