Battery

Abstract

To provide a battery with improved heat radiation performance.SOLUTION: The battery 10 includes an electrode assembly 14 including a positive electrode collector and a negative electrode collector, a case 12 housing the electrode assembly 14, a first collector terminal 20 joined to the positive electrode collector, a second collector terminal 22 joined to the negative electrode collector, a first insulating member 24 insulating the case 12 and the first collector terminal 20 from each other, a second insulating member 26 insulating the case 12 and the second collector terminal 22 from each other, and a plurality of first external terminals 28 inserted through the case 12 and electrically connected to the first collector terminal 20. And a second external terminal 30 inserted into the case 12 and electrically connected to the second collector terminal 22.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a battery. [Background technology]

[0002] Patent Document 1 discloses a battery in which an electrode body is housed in a case. The battery disclosed in Patent Document 1 has a positive electrode current collector terminal and a negative electrode current collector terminal provided in the case, and the positive electrode current collector terminal is connected to the positive electrode of the electrode body via multiple positive electrode current collector tabs, and the negative electrode current collector terminal is connected to the negative electrode of the electrode body via multiple negative electrode current collector tabs. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2023-61187 Summary of the Invention [Problem to be solved by the invention]

[0004] 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 Patent Document 1, 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.

[0005] In consideration of the above, an object of the present invention is to provide a battery with improved heat dissipation performance. [Means for solving the problem]

[0006] 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.

[0007] In the battery according to claim 1, 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.

[0008] 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, allowing more heat generated in the electrode assembly to be dissipated.

[0009] The battery according to claim 2 is the battery according to 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.

[0010] In the battery according to claim 2, the first external terminal is joined to the first current collecting terminals on both sides when viewed from the stacking direction of the electrode assembly, so 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 when viewed from the stacking direction of the electrode assembly, so heat generated in the electrode assembly is dispersed and transferred to both sides of the second external terminal. This makes it possible to prevent localized heat generation in the first current collecting terminal and the second current collecting terminal.

[0011] The battery of claim 3 is the same as claim 1, wherein the electrode body has a longitudinal direction and a transverse 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.

[0012] In the battery of claim 3, 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.

[0013] A battery according to a fourth aspect of the present invention is the battery according to the first aspect, wherein a plurality of the first external terminals and a plurality of the second external terminals are provided.

[0014] In the battery according to claim 4, 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.

[0015] The battery according to claim 5 is the battery according to claim 4, wherein the plurality of first external terminals are provided adjacent to each other without sandwiching the positive electrode current collector therebetween, and the plurality of second external terminals are provided adjacent to each other without sandwiching the negative electrode current collector therebetween.

[0016] In the battery according to claim 5, 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.

[0017] The battery of claim 6 is the same as claim 1, wherein 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.

[0018] In the battery according to claim 6, the first external terminal is fixed with the first insulating member sandwiched between the case and the first current collector terminal, thereby preventing electrical conduction between the case and the first current collector terminal with a simple structure. Similarly, the second external terminal is fixed with the second insulating member sandwiched between the case and the second current collector terminal with a simple structure, thereby preventing electrical conduction between the case and the second current collector terminal with a simple structure.

[0019] A battery according to a seventh aspect of the present invention is the battery according to the first aspect, wherein the first external terminal and the second external terminal are provided at positions facing the widthwise center of the electrode assembly when viewed from the stacking direction of the electrode assembly.

[0020] In the battery according to claim 7, 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.

[0021] The battery of claim 8 is the same as claim 1, wherein 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.

[0022] In the battery according to claim 8, the first external terminal and the second external terminal are arranged diagonally when viewed in the stacking direction of the electrode assembly, thereby ensuring a long heat dissipation path and preventing heat from building up inside the case.

[0023] The battery of claim 9 is the battery of 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.

[0024] In the battery according to claim 9, the positive electrode current collector is joined to the first current collecting terminal at least half its length, and the negative electrode current collector is joined to the second current collecting terminal at least half 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 at less than half its length, or a configuration in which the negative electrode current collector is joined to the second current collecting terminal at less than half its length.

[0025] The battery according to claim 10 is the battery according to claim 1, 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.

[0026] In the battery according to claim 10, 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 against the first insulating member and losing its 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 against the second insulating member and losing its insulating state. [Effects of the Invention]

[0027] As described above, the battery according to the present invention can improve heat dissipation performance. [Brief explanation of the drawings]

[0028] [Figure 1] FIG. 2 is a schematic cross-sectional view of a battery cell according to an embodiment. [Figure 2] FIG. 2 is a cross-sectional view showing a state cut along line 2-2 in FIG. [Figure 3] FIG. 2 is an enlarged cross-sectional view showing a main part of FIG. 1. [Figure 4] FIG. 4 is a cross-sectional view taken along line 4-4 in FIG. 3. [Figure 5] FIG. 4 is a cross-sectional view illustrating a step of joining a positive electrode current collector to a first current collecting terminal. [Figure 6] FIG. 3 is a cross-sectional view showing a state in which a positive electrode current collector is joined to a first current collector terminal. [Figure 7] FIG. 10 is a schematic cross-sectional view of a battery cell according to a first modified example. [Figure 8] FIG. 10 is a schematic cross-sectional view of a battery cell according to a second modified example. [Figure 9] FIG. 10 is a schematic cross-sectional view of a battery cell according to a third modified example. DETAILED DESCRIPTION OF THE INVENTION

[0029] 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 be able to store power to be supplied to a drive motor (not shown).

[0030] 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 the driving source, such as hybrid vehicles (HVs) and plug-in hybrid electric vehicles (PHEVs), in addition to BEVs (Battery Electric Vehicles).

[0031] A 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 lid portion 12B that closes an opening on one side of the peripheral wall portion 12A, and a negative electrode side lid portion 12C that closes an opening on the other side of the peripheral wall portion 12A.

[0032] The peripheral wall 12A is formed of metal in a generally rectangular cylindrical shape with both ends open, and is large enough to accommodate the electrode assembly 14. The positive electrode side lid 12B is a metal member that is fixed to one opening of the peripheral wall 12A by fitting, welding, or other means, and closes the opening on one side of the peripheral wall 12A. The negative electrode side lid 12C is a metal member that is fixed to the other opening of the peripheral wall 12A by fitting, welding, or other means, and closes the opening on the other side of the peripheral wall 12A.

[0033] 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 formed 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.

[0034] 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 is preferable as the negative electrode current collector 48.

[0035] The negative electrode composite material 46 is coated on both sides of the negative electrode current collector 48. The negative electrode composite material 46 is a mixture of a negative electrode active material, a conductive auxiliary material, a binder, etc. Examples of the negative electrode active material include at least one selected from the group consisting of natural graphite, artificial graphite, hard carbon (carbon with low graphitization property), soft carbon (carbon with high graphitization property), 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, mesocarbon microbeads, etc. As the negative electrode active material, artificial graphite is preferred.

[0036] The solid electrolyte 44 is laminated on the side of the negative electrode composite material 46 opposite to the negative electrode current collector 48. Further, the positive electrode composite material 42 is laminated on the side of the solid electrolyte 44 opposite to the negative electrode composite material 46. The positive electrode composite material 42 is a mixture of a positive electrode active material, a conductive auxiliary material, a binder, etc., and is coated on the positive electrode current collector 40. The positive electrode active material is not particularly limited, and conventionally known materials can be appropriately used. For example, LiCoO2, LiNiO2, LiMnO2, LiMn2O4, Li(NiCoMn)O2, Li(NiCoAl)O2, and LiFePO4 can be mentioned as the positive electrode active material. Note that the positive electrode active material particles may be Hi-Nickel (a positive electrode active material with a high Ni ratio) or a Li-Ni-Co-Mn-based composite oxide or a ternary positive electrode active material.

[0037] The positive electrode current collector 40 is formed of a metal foil, and as the positive electrode current collector 40, an aluminum foil is preferred. Thus, as an example, in the electrode body 14 of this embodiment, the negative electrode current collector 48 is disposed at the center in the stacking direction, and the positive electrode current collectors 40 are disposed on both sides of the negative electrode current collector 48. Therefore, the number of positive electrode current collectors 40 is larger than that of the negative electrode current collector 48.

[0038] 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.

[0039] 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, is divided into three: a first positive electrode tab 16A, a second positive electrode tab 16B, and a third positive electrode tab 16C.

[0040] 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.

[0041] On the other hand, the negative electrode tab 18 is formed by collecting negative electrode foils extending from multiple negative electrode current collectors 48 that make up the electrode body 14, and in this embodiment, as an example, it is divided into three tabs: a first negative electrode tab 18A, a second negative electrode tab 18B, and a third negative electrode tab 18C.

[0042] 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 collecting 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 collecting 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 collecting terminal 22 described later.

[0043] The first current collecting terminal 20 is provided inside the case 12 and is an elongated metal member extending along the width direction of the electrode assembly 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.

[0044] The second current collecting terminal 22 is provided inside the case 12 and is an elongated metal member extending along the width direction of the electrode assembly 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.

[0045] 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.

[0046] 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 this 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.

[0047] 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.

[0048] The outer flange portion 28B has a larger diameter than the shaft portion 28A and is located outside the positive electrode side lid portion 12B. The inner 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 outer terminal 28 is exposed to the outside of the case 12.

[0049] 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.

[0050] 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 with the first insulating member 24 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.

[0051] Furthermore, since the first external terminal 28 is electrically connected to the first current collecting 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 current collecting terminal 20.

[0052] 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.

[0053] Furthermore, the electrode body 14 of this embodiment is joined to first current collector terminals 20 on both sides of the first external terminal 28 when viewed from the stacking direction, and is joined to 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.

[0054] 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.

[0055] 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.

[0056] 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.

[0057] 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. Hereinafter, the process of joining the positive electrode tab 16 to the first current collector terminal 20 will be described with reference to Figs. 5 and 6.

[0058] 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 collecting 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 collecting terminal 20. As shown in Fig. 5, the positive electrode tab 16 is bent and placed on top of the first current collecting terminal 20, and an anvil 100 serving as a receiving jig is placed on one side of the first current collecting terminal 20.

[0059] An ultrasonic horn 102 is placed on the other surface of the first current collecting terminal 20, and while the ultrasonic horn 102 is pressed against the positive electrode tab 16, ultrasonic waves are generated to vibrate the ultrasonic horn 102, 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.

[0060] 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 where the ultrasonic horn 102 is pressed. Note that the unevenness and grooves are exaggerated in Fig. 6 for ease of explanation.

[0061] 1, the first insulating member 24 is sandwiched between the first current collecting terminal 20 and the positive electrode side lid portion 12B, so that the uneven surface of the first current collecting terminal 20 comes into contact with the first insulating member 24. The second current collecting terminal 22 is ultrasonically bonded in the same manner as the first current collecting terminal 20, so that the surface of the second current collecting terminal 22 facing the second insulating member 26 is formed unevenly. (action) Next, the operation of the battery cell 10 according to this embodiment will be described.

[0062] 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.

[0063] 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.

[0064] 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, and therefore heat can be dissipated in a balanced manner from both the first external terminals 28 and the second external terminals 30.

[0065] Furthermore, in the battery cell 10 of this embodiment, the positive electrode tabs 16 are joined to the first current collecting terminals 20 on both sides of the first external terminal 28 when viewed from 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 collecting terminals 22 on both sides of the second external terminal 30 when viewed from 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 prevent localized heat generation in the first current collecting terminal 20 and the second current collecting terminal 22.

[0066] Furthermore, in the battery cell 10 of this embodiment, the positive electrode tab 16 is joined to the first current collector terminal 20 at a length equal to or greater than half of its length, and the negative electrode tab 18 is joined to the second current collector terminal 22 at a length equal to or greater than half of its length. This improves heat dissipation performance compared to a configuration in which the positive electrode tab 16 is joined to the first current collector terminal 20 at a length less than half, or a configuration in which the negative electrode tab 18 is joined to the second current collector terminal 22 at a length less than half.

[0067] 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.

[0068] 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 prevent 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 prevent electrical conduction between the case 12 and the second current collector terminal 22.

[0069] Furthermore, in this embodiment, the surface of the first current collecting terminal 20 facing the first insulating member 24 is formed unevenly, as shown in Fig. 6. 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, the surface of the second current collecting terminal 22 facing the second insulating member 26 is formed unevenly, so 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.

[0070] 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.

[0071] (First Modification) 7 is a schematic cross-sectional view of a battery cell 50 according to a first modified example. As shown in this Fig. 7, the battery cell 50 according to this modified example has three first external terminals 28 and two second external terminals 30.

[0072] 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 a 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.

[0073] 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 collecting terminal 20. 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 collecting terminal 20.

[0074] 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.

[0075] 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.

[0076] 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 part 12C and is joined to the second current collecting 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 part 12C and is joined to the second current collecting terminal 22.

[0077] 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. This allows for space savings.

[0078] 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.

[0079] (Second Modification) Fig. 8 is a schematic cross-sectional view of a battery cell 60 according to a second modified example. As shown in Fig. 8, the battery cell 60 according to this modified example has 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.

[0080] 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.

[0081] 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.

[0082] 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.

[0083] 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 this modified example, only one negative electrode tab 18 is provided.

[0084] In the battery cell 60 of this modification, 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.

[0085] (Third Modification) Fig. 9 is a schematic cross-sectional view of a battery cell 70 according to a third modified example. As shown in Fig. 9, the battery cell 70 according to this modified example has three first external terminals 28 and two second external terminals 30, similar to the first modified example, but the positions of the first external terminals 28 and the second external terminals 30 are different.

[0086] 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.

[0087] 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 collecting terminal 20. The positive electrode tab 16 is formed 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.

[0088] 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.

[0089] 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.

[0090] 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.

[0091] The battery cells 10, 50, 60, and 70 according to the embodiments and modifications have been described above, but the present invention is not limited thereto and can be embodied in various forms without departing from the spirit of the present invention. 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, the present invention 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.

[0092] Furthermore, in the above embodiment and modified example, the first external terminal 28 and the second external terminal 30 are fixed by crimping, but this is not limitative and they may be fixed by other methods.

[0093] The following notes are provided regarding the above embodiment.

[0094] (Appendix 1) an electrode assembly including a positive electrode current collector and a negative electrode current collector; a case for accommodating the electrode assembly; a first current collecting terminal provided inside the case and joined to the positive electrode current collector; a second current collecting terminal provided inside the case and joined to the negative electrode 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, one end of which is exposed to the outside of the case, and the other end of which is electrically connected to the first current collecting terminal; a second external terminal that is inserted into the case, one end of which is exposed to the outside of the case, and the other end of which is electrically connected to the second current collecting terminal; and The battery includes a plurality of first external terminals and a plurality of second external terminals. (Appendix 2) the positive electrode current collector is joined to the first current collecting terminal on both sides thereof, sandwiching the first external terminal when viewed from the stacking direction of the electrode body; 2. The battery according to claim 1, wherein 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 assembly. (Appendix 3) The electrode body has a longitudinal direction and a lateral direction when viewed from the stacking direction, The battery according to claim 1 or 2, wherein 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. (Appendix 4) 4. The battery according to claim 1, wherein the first external terminal and the second external terminal are each provided in plural. (Appendix 5) the plurality of first external terminals are provided adjacent to each other without sandwiching the positive electrode current collector therebetween, 5. The battery according to claim 4, wherein the second external terminals are adjacent to each other without sandwiching the negative electrode current collector therebetween. (Appendix 6) the first external terminal is fixed in a state in which the first insulating member is sandwiched between the case and the first current collecting terminal, 6. The battery according to claim 1, wherein the second external terminal is fixed with the second insulating member sandwiched between the case and the second current collector terminal. (Appendix 7) The battery according to any one of claims 1 to 6, 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. (Appendix 8) 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, 7. The battery according to any one of claims 1 to 6, wherein the second external terminal is provided at a position facing the other end of the electrode assembly in the width direction when viewed from the stacking direction of the electrode assembly. (Appendix 9) 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 collector terminal over a length that is half or more of the length of the first current collector terminal when viewed in the stacking direction of the electrode assembly, The battery according to any one of claims 1 to 8, wherein the negative electrode current collector is joined to the second current collector terminal over a length that is at least half the length of the second current collector terminal when viewed in the stacking direction of the electrode assembly. (Appendix 10) The battery according to any one of claims 1 to 9, wherein a surface of the first current collector terminal facing the first insulating member and a surface of the second current collector terminal facing the second insulating member are formed unevenly. [Explanation of symbols]

[0095] 10, 50, 60, 70 battery cells (batteries) 12 cases 14 Electrode body 20 1st current collector terminal 22 2nd current collector terminal 24 First insulating member 26 Second insulating member 28 1st external terminal 30 2nd external terminal 40 Positive current collector 48 Negative current collector

Claims

1. an electrode assembly including a positive electrode current collector and a negative electrode current collector; a case for accommodating the electrode assembly; a first current collecting terminal provided inside the case and joined to the positive electrode current collector; a second current collecting terminal provided inside the case and joined to the negative electrode 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, one end of which is exposed to the outside of the case, and the other end of which is electrically connected to the first current collecting terminal; a second external terminal that is inserted into the case, one end of which is exposed to the outside of the case, and the other end of which is electrically connected to the second current collecting terminal; and The battery includes a plurality of first external terminals and a plurality of second external terminals.

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

3. The electrode body has a longitudinal direction and a lateral direction when viewed from the stacking direction, The battery according to claim 1 , wherein 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 plurality of first external terminals are provided adjacent to each other without sandwiching the positive electrode current collector therebetween, The battery according to claim 4 , wherein the plurality of second external terminals are provided adjacent to each other without sandwiching the negative electrode current collector therebetween.

6. the first external terminal is fixed in a state in which the first insulating member is sandwiched between the case and the first current collecting terminal, The battery according to claim 1 , wherein the second external terminal is fixed with the second insulating member sandwiched between the case and the second current collector terminal.

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

8. 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, The battery according to claim 1 , wherein the second external terminal is provided at a position facing the other end of the electrode assembly in the width direction when viewed from the stacking direction of the electrode assembly.

9. 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 collector terminal over a length that is at least half the length of the first current collector terminal when viewed in the stacking direction of the electrode assembly, The battery according to claim 1 , wherein the negative electrode current collector is joined to the second current collector terminal over a length that is at least half the length of the second current collector terminal when viewed in the stacking direction of the electrode assembly.

10. The battery according to claim 1 , wherein a surface of the first current collector terminal facing the first insulating member and a surface of the second current collector terminal facing the second insulating member are formed with an uneven shape.

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