Connect the leads and battery

Abstract

According to an embodiment, a connecting lead is provided, which connects a collector sheet of an electrode group to an electrode terminal in a battery. The connecting lead includes a top plate portion and a leg portion, the leg portion is bent toward one side in the thickness direction of the top plate portion relative to the top plate portion, and a bending line at a bending position relative to the top plate portion is along the width direction of the top plate portion. The leg portion includes an extended portion located away from the bending position relative to the top plate portion, and the extended portion includes a side surface, which is relayed between a pair of main surfaces on the outer surface and faces one side in the width direction of the top plate portion. The side surface is bonded to the collector sheet.

Description

Technical Field

[0001] Embodiments of the present invention relate to connecting leads and batteries. Background Art

[0002] With the progress of electronic devices such as mobile phones and personal computers, batteries such as secondary batteries used in these electronic devices require miniaturization and lightweight. As a secondary battery that has achieved miniaturization and lightweight and has a higher energy density, a lithium-ion secondary battery can be cited. On the other hand, as a large and large-capacity power source carried in vehicles such as electric vehicles, hybrid vehicles, electric motorcycles and forklifts, secondary batteries such as lead-acid batteries and nickel-metal hydride batteries can be used. In addition, as a large and large-capacity power source carried in a vehicle, a lithium-ion secondary battery with a higher energy density has been developed for practical use in recent years. For the development of lithium-ion secondary batteries carried by vehicles, it is required to realize the high life of the battery and improve safety, etc., and it is required to realize the large-scale and large-capacity of the battery.

[0003] As a battery such as a lithium-ion secondary battery, there is a case where an electrode group having a positive electrode and a negative electrode is housed in the internal cavity of an outer container. In this battery, the outer container has a bottom wall and a peripheral wall, and the internal cavity of the outer container opens to the side opposite to the bottom wall in the height direction. In addition, a cover member is installed on the peripheral wall of the outer container, and the opening of the internal cavity is closed by the cover member. In addition, for the battery, an electrode terminal is installed on the outer surface of the cover member, and in the internal cavity, a collector sheet protrudes from the electrode group to the outer peripheral side. In addition, the collector sheet is electrically connected to the electrode terminal via a connecting lead (lead).

[0004] In the above-mentioned battery, when the device equipped with the battery vibrates, impact or the like may be applied to the connecting lead from the outside. Therefore, it is required to ensure that the connecting lead has high impact resistance to impact or the like. In addition, the connecting lead forms a current path between the electrode group and the electrode terminal. Therefore, it is required to ensure that the resistance of the connecting lead is low.

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: Japanese Patent Application Publication No. 2011-71109 Summary of the invention

[0008] 1. Technical issues to be resolved

[0009] The technical problem to be solved by the present invention is to provide a connecting lead that can ensure high impact resistance and low electrical resistance, and a battery including the connecting lead.

[0010] (II) Technical solution

[0011] According to an embodiment, a connecting lead for connecting a collector sheet of an electrode group to an electrode terminal in a battery is provided. The connecting lead includes a top plate portion and a leg portion, the leg portion is bent toward one side in the thickness direction of the top plate portion relative to the top plate portion, and a bending line at a bending position relative to the top plate portion is along the width direction of the top plate portion. The leg portion includes an extended portion located away from the bending position relative to the top plate portion. The extended portion includes: a first main surface, which faces a side of an intersecting direction intersecting both the width direction of the top plate portion and the thickness direction of the top plate portion on the outer surface; a second main surface, which faces a side opposite to the first main surface on the outer surface; and a side surface, which is relayed between the first main surface and the second main surface on the outer surface and faces one side in the width direction of the top plate portion. The side surface is bonded to the collector sheet.

[0012] According to an embodiment, a battery comprises: the above-mentioned connecting lead, an outer container, an electrode group, a cover member, and an electrode terminal. The outer container comprises a bottom wall and a peripheral wall, and an internal cavity for arranging the connecting lead is defined by the bottom wall and the peripheral wall. The electrode group comprises a positive electrode and a negative electrode, and comprises a collector sheet joined to the connecting lead on the side of the extended portion of the foot. The cover member is mounted on the peripheral wall at the end on the side opposite to the bottom wall, and the opening of the internal cavity of the outer container is closed. The electrode terminal is mounted on the outer surface of the cover member and is connected to the top plate portion of the connecting lead. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a perspective view schematically showing the battery according to the first embodiment.

[0014] Figure 2 This is a perspective view schematically showing the battery of the first embodiment in a state where the components are exploded.

[0015] Figure 3 It is a perspective view showing the structure of the connecting lead according to the first embodiment.

[0016] Figure 4 This is a cross-sectional view schematically showing a portion of a connection lead joined to a current collector tab and its vicinity according to the first embodiment.

[0017] Figure 5 This is a schematic diagram for explaining an example of the method for manufacturing the connecting lead according to the first embodiment.

[0018] Figure 6 It is a perspective view showing the structure of a connecting lead according to a modified example. DETAILED DESCRIPTION

[0019] Hereinafter, embodiments will be described with reference to the drawings.

[0020] (First Embodiment)

[0021] Figure 1 and Figure 2 1 shows a battery 1 according to a first embodiment. Figure 1 and Figure 2 As shown in FIG. 1 , the battery 1 includes an electrode group 2, an outer container 3, and a cover member 5. The outer container 3 and the cover member 6 are each formed of a metal such as aluminum, an aluminum alloy, iron, copper, or stainless steel. Here, the battery 1 is defined as follows: a longitudinal direction (directions indicated by arrows X1 and X2), a transverse direction (directions indicated by arrows Y1 and Y2) intersecting (perpendicular or substantially perpendicular) the longitudinal direction, and a height direction (directions indicated by arrows Z1 and Z2) intersecting (perpendicular or substantially perpendicular) the longitudinal and transverse directions. For the battery 1 and the outer container 3, the longitudinal dimension is smaller than the transverse dimension and the height dimension.

[0022] The outer container 3 includes a bottom wall 6 and a peripheral wall 7. The internal cavity 8 for accommodating the electrode group 2 is defined by the bottom wall 6 and the peripheral wall 7. In the outer container 3, the internal cavity 8 is open in the height direction toward the side opposite to the side where the bottom wall 6 is located. The peripheral wall 7 includes two pairs of side walls 11 and 12. The pair of side walls 11 are opposed to each other across the internal cavity 8 in the lateral direction. The pair of side walls 12 are opposed to each other across the internal cavity 8 in the longitudinal direction. The side walls 11 are respectively extended continuously in the longitudinal direction between the side walls 12. The side walls 12 are respectively extended continuously in the lateral direction between the side walls 11. The cover member 5 is attached to the peripheral wall 7 at the end on the side opposite to the bottom wall 6. Therefore, the cover member 5 closes the opening of the internal cavity 8 of the outer container 3. The cover member 5 and the bottom wall 6 are opposed to each other across the internal cavity 8 in the height direction.

[0023] The electrode group 2 includes a positive electrode 13 and a negative electrode 14. In the electrode group 2, a separator (not shown) is interposed between the positive electrode 13 and the negative electrode 14. The separator is formed of a material having electrical insulation properties, and electrically insulates the positive electrode 13 from the negative electrode 14.

[0024] The positive electrode 13 comprises: a positive electrode collector 13A such as a positive electrode collector foil, and a positive electrode active material-containing layer (not shown) carried on the surface of the positive electrode collector 13A. The positive electrode collector 13A is not limited thereto, and may be, for example, an aluminum foil or an aluminum alloy foil, and may have a thickness of about 10 μm to 20 μm. The positive electrode active material-containing layer comprises a positive electrode active material, and may arbitrarily contain a binder and a conductive agent. The positive electrode active material is not limited thereto, and examples thereof include oxides, sulfides, and polymers that can absorb and release lithium ions. The positive electrode collector 13A comprises a positive electrode collector sheet 13B as a portion that does not carry the positive electrode active material layer.

[0025] The negative electrode 14 comprises: a negative electrode collector 14A such as a negative electrode collector foil, and a negative electrode active material-containing layer (not shown) carried on the surface of the negative electrode collector 14A. The negative electrode collector 14A is not limited thereto, and may be, for example, aluminum foil, aluminum alloy foil or copper foil, and may have a thickness of about 10 μm to 20 μm. The negative electrode active material-containing layer comprises a negative electrode active material, and may arbitrarily contain a binder and a conductive agent. The negative electrode active material is not particularly limited, and examples thereof include metal oxides, metal sulfides, metal nitrides and carbon materials that can absorb and release lithium ions. The negative electrode collector 14A comprises a negative electrode collector sheet 14B as a portion that does not carry the negative electrode active material layer.

[0026] exist Figure 2 In an electrode group 2 of an example of the present invention, the positive electrode 13, the negative electrode 14 and the separator are wound around the winding axis in a state where the separator is sandwiched between the positive electrode active material layer and the negative electrode active material layer. In another example, the electrode group 2 has a stacked structure in which a plurality of positive electrodes 13 and a plurality of negative electrodes 14 are alternately stacked, and a separator is provided between the positive electrode 13 and the negative electrode 14. In the electrode group 2, the positive electrode collector sheet 13B protrudes relative to the negative electrode 14 and the separator. In addition, the negative electrode collector sheet 14B protrudes to the side opposite to the protruding direction of the positive electrode collector sheet 13B relative to the positive electrode 13 and the separator.

[0027] The electrode group 2 is defined as follows: a width direction (direction indicated by arrows Z3 and Z4) intersecting (perpendicular or substantially perpendicular) with the protruding direction (direction indicated by arrows Y3 and Y4) of the collector sheets 13B and 14B, and a thickness direction (direction indicated by arrows X3 and X4) intersecting with both the protruding direction and the width direction of the collector sheets 13B and 14B. In addition, for the electrode group 2, the dimension in the thickness direction is smaller than the dimension in the protruding direction and the dimension in the width direction of the collector sheets 13B and 14B. Therefore, the electrode group 2 is formed into a flat shape. In addition, the positive electrode collector sheet 13B and the negative electrode collector sheet 14B are each provided with a bundle 15 in which a plurality of strip-shaped portions are bundled.

[0028] In the present embodiment, the electrode group 2 is arranged in the internal cavity 8 in a state where the width direction is consistent or substantially consistent with the height direction of the battery 1, and the thickness direction is consistent or substantially consistent with the longitudinal direction of the battery 1. In addition, in the internal cavity 8 of the outer container 3, the positive electrode collector tab 13B protrudes to one side in the lateral direction relative to the negative electrode 14 and the separator. In addition, the negative electrode collector tab 14B protrudes to the side opposite to the side where the positive electrode collector tab 13B protrudes in the lateral direction relative to the positive electrode 13 and the separator.

[0029] In addition, in the internal cavity 8, an electrolyte (not shown) is retained (impregnated) in the electrode group 2. The electrolyte may be a non-aqueous electrolyte obtained by dissolving an electrolyte in an organic solvent, or an aqueous electrolyte such as an aqueous solution. A gel electrolyte may be used instead of the electrolyte, or a solid electrolyte may be used. When a solid electrolyte is used as the electrolyte, the solid electrolyte is placed between the positive electrode 13 and the negative electrode 14 in the electrode group instead of the separator. At this time, the positive electrode 13 is electrically insulated from the negative electrode 14 by the solid electrolyte.

[0030] In the battery 1, a pair of electrode terminals 16 are installed on the outer surface (upper surface) of the cover member 5. The electrode terminal 16 is formed of a conductive material such as metal. One of the electrode terminals 16 is the positive terminal of the battery 1, and the other of the electrode terminals 16 is the negative terminal of the battery 1. In addition, a pair of through holes 17 are provided on the cover member 5, and the through holes 17 penetrate the cover member 5 in the height direction of the battery 1. An insulating member 18 is provided between each electrode terminal 16 and the cover member 5. In addition, an insulating gasket 19 is arranged in each through hole 17. Each electrode terminal 16 is electrically insulated from the cover member 5 and the outer container 3 by the insulating member 18 and the insulating gasket 19.

[0031] A pair of connecting leads 20 are arranged in the internal cavity 8 of the outer container 3. The positive electrode collector sheet 13B of the electrode group 2 is electrically connected to the corresponding one of the electrode terminals 16, that is, the positive terminal, via the corresponding one of the connecting leads (leads) 20, that is, the positive electrode side connecting lead (positive electrode lead). In addition, the negative electrode collector sheet 14B of the electrode group 2 is electrically connected to the corresponding one of the electrode terminals 16, that is, the negative terminal, via the corresponding one of the connecting leads 20, that is, the negative electrode side connecting lead (negative electrode lead). The connecting leads 20 are each formed of a conductive material such as a metal. As the conductive material forming the connecting lead 20, aluminum, stainless steel, copper, iron, etc. can be cited.

[0032] In the present embodiment, the current collector tabs 13B and 14B are respectively joined to the corresponding one of the connection leads 20 via the backup leads 22. The binding portion 15 of each of the current collector tabs 13B and 14B is sandwiched by the backup leads 22. The current collector tabs 13B and 14B are respectively joined to the corresponding one of the connection leads 20 via the binding portion 15 sandwiched by the backup leads 22.

[0033] In addition, a pair of insulating protective members 21 and an electrode pressing member 23 are arranged in the internal cavity 8 of the outer container 3. Each insulating protective member 21 is formed of a material having electrical insulation. One of the connecting leads 20, namely the positive electrode side connecting lead, and the positive electrode collector sheet 13B are respectively prevented from contacting the outer container 3 by using a corresponding one of the insulating protective members 21, and are electrically insulated from the outer container 3. In addition, one of the connecting leads 20, namely the negative electrode side connecting lead, and the negative electrode collector sheet 14B are respectively prevented from contacting the outer container 3 by using a corresponding one of the insulating protective members 21, and are electrically insulated from the outer container 3. The insulating protective members 21 are fixed to the electrode group 2 by insulating tapes 25. The insulating tapes 25 are formed of a material having electrical insulation.

[0034] In addition, the electrode pressing member 23 is arranged between the electrode group 2 and the cover member 5 in the height direction of the battery 1. The electrode pressing member (internal insulating member) 23 is formed of a material having electrical insulation. The positive electrode collector tab 13B, the negative electrode collector tab 14B and the pair of connecting leads 20 are prevented from contacting the cover member 5 by the electrode pressing member 23 and are electrically insulated from the cover member 5.

[0035] In addition, Figure 1 and Figure 2 In one example, a gas release valve 26 and a liquid injection port 27 are formed on the cover member 5. A sealing plate 28 for closing the liquid injection port 27 is welded to the outer surface of the cover member 5. In addition, the gas release valve 26 and the liquid injection port 27 may not be provided on the battery 1.

[0036] Figure 3 20 shows the structure of the connecting lead wire 20. Figure 4 The connecting lead 20 and the current collector (13B or 14B) and its vicinity are shown. Figure 3 and Figure 4 As shown, the connecting lead 20 each includes a top plate portion 31 and a leg portion 32. The top plate portion 31 has extension ends E1 and E2, and the top plate portion 31 extends from the extension end (first extension end) E1 to the extension end (second extension end) E2 along the extension direction (the direction indicated by the arrow Y5 and the arrow Y6). In addition, for the top plate portion 31, there are defined: a width direction (the direction indicated by the arrow X5 and the arrow X6) that intersects (perpendicularly or substantially perpendicularly) with the extension direction (length direction), and a thickness direction (the direction indicated by the arrow Z5 and the arrow Z6) that intersects with both the extension direction (length direction) and the width direction. In addition, for the connecting lead 20, the extension direction of the top plate portion 31 is defined as an intersecting direction that intersects with both the width direction and the thickness direction of the top plate portion 31. In addition, a through hole 33 is formed on the top plate portion 31, and the through hole 33 penetrates the top plate portion 31 in the thickness direction.

[0037] For each of the connecting leads 20 of the present embodiment, only one leg portion 32 is formed. The leg portion 32 includes a leg connection portion 35 connected to the extended end E2 of the top plate portion 31. The leg portion 32 is bent relative to the top plate portion 31 with the leg connection portion 35 (extended end E2) as a bending position. The leg portion 32 is bent toward one side in the thickness direction of the top plate portion 31 relative to the top plate portion 31. Therefore, the leg portion 32 protrudes toward one side in the thickness direction of the top plate portion 31 relative to the top plate portion 31. The bending line at the bending position of the leg portion 32 relative to the top plate portion 31 is along the width direction of the top plate portion 31. In the present embodiment, the bending angle of the leg portion 32 relative to the top plate portion 31 at the leg connection portion 35 (bending position) is 90 degrees or approximately 90 degrees.

[0038] The foot portion 32 extends straight or approximately straight from a bending position (foot connection portion 35) relative to the top plate portion 31 to a protruding end protruding from the top plate portion 31. That is, the foot portion 32 is not bent except for the foot connection portion 35, and is extended to the protruding end. Furthermore, the foot portion 32 is extended to the protruding end along the thickness direction of the top plate portion 31. In addition, the width direction (board width direction) of the foot portion 32 is consistent with or approximately consistent with the width direction (board width direction) of the top plate portion 31. Furthermore, the thickness direction (board thickness direction) of the foot portion 32 intersects (perpendicularly or approximately perpendicularly) with both the width direction of the top plate portion 31 and the thickness direction of the top plate portion 31. Therefore, the thickness direction of the foot portion 32 is consistent with or approximately consistent with the extension direction (length direction) of the top plate portion 31, and is consistent with or approximately consistent with the intersection direction of the connecting lead 20.

[0039] The leg portion 32 includes an extension portion 36, which is located at a position away from the leg connection portion 35 on the side opposite to the top plate portion 31. The extension portion 36 is provided away from the bending position of the leg portion 32 relative to the top plate portion 31, and is provided at a position farther from the top plate portion 31 than the leg connection portion 35. In addition, in the present embodiment, the extension portion 36 forms a protruding end of the leg portion 32 protruding from the top plate portion 31.

[0040] In the leg 32, a cross-sectional shape changing portion 37 is formed in the intermediate portion between the leg connection portion 35 (bending position) and the extension portion 36. In the present embodiment, the cross-sectional shape changing portion 37 is adjacent to the extension portion 36 on the side where the top plate portion 31 is located. Here, the extension direction of the leg 32 from the leg connection portion 35 to the protruding end is defined. The extension direction of the leg 32 intersects (perpendicularly or substantially perpendicularly) with both the width direction of the leg 32 and the thickness direction of the leg 32. In the cross-sectional shape changing portion 37, the cross-sectional shape of the leg 32 perpendicular or substantially perpendicular to the extension direction changes along the extension direction of the leg 32. Furthermore, in the cross-sectional shape changing portion 37, the size (width) of the leg 32 in the width direction of the leg 32 and the size (thickness) of the leg 32 in the thickness direction of the leg 32 change along the extension direction of the leg 32.

[0041] In addition, the outer surface of the extension portion 36 includes: a pair of main surfaces 41, 42 and a pair of side surfaces 43, 44. The main surface (first main surface) 41 faces one side in the direction of intersection of the connection lead 20, that is, one side in the thickness direction of the leg portion 32. The main surface (second main surface) 42 faces the side opposite to the main surface 41 in the direction of intersection of the connection lead 20. In addition, the main surface 42 is arranged away from the main surface 41 in the direction of intersection of the connection lead 20. The distance between the main surfaces 41, 42 is the dimension of the extension portion 36 in the thickness direction of the leg portion 32 (the direction of intersection of the connection lead 20).

[0042] The side surfaces 43 and 44 are respectively extended continuously from the main surface 41 to the main surface 42 along the thickness direction of the leg portion 32. Therefore, the side surfaces 43 and 44 are respectively relayed between the main surfaces 41 and 42. The side surface (first side surface) 43 is connected to one of the two edges of the main surface 41, and is connected to one of the two edges of the main surface 42. In addition, the side surface (second side surface) 44 is connected to the edge of the main surface 41 on the side opposite to the side connected to the side surface 43, and is connected to the edge of the main surface 42 on the side opposite to the side connected to the side surface 43. The side surface 43 faces one side in the width direction of the leg portion 32, that is, one side in the width direction of the top plate portion 31. The side surface 44 faces the side opposite to the side surface 43 in the width direction of the leg portion 32. And the side surface 44 is arranged away from the side surface 43 in the width direction of the leg portion 32. The distance between the side surfaces 43 and 44 is the dimension of the extended portion 36 in the width direction of the leg portion 32 (the width direction of the top plate portion 31).

[0043] The outer surface of the cross-sectional shape changing portion 37 includes: a pair of relay main surfaces 45, 46 and a pair of relay side surfaces 47, 48. The relay main surface (first relay main surface) 45 is adjacent to the main surface 41 on the side where the top plate portion 31 (leg connecting portion 35) is located. The relay main surface 45 faces the side that the main surface 41 faces in the intersecting direction of the connecting lead 20. The relay main surface (second relay main surface) 46 is adjacent to the main surface 42 on the side where the top plate portion 31 is located. The relay main surface 46 faces the side opposite to the relay main surface 45 in the intersecting direction of the connecting lead 20. And, the relay main surface 46 is arranged away from the relay main surface 45 in the intersecting direction of the connecting lead 20. For the cross-sectional shape changing portion 37, the dimension between the relay main surfaces 45, 46 is defined as the dimension in the thickness direction of the leg portion 32 (the intersecting direction of the connecting lead 20).

[0044] The relay side surface (first relay side surface) 47 is adjacent to the side surface 43 on the side where the top plate portion 31 (leg connection portion 35) is located. The relay side surface 47 faces the side to which the side surface 43 faces in the width direction of the leg portion 32. The relay side surface (second relay side surface) 48 is adjacent to the side surface 44 on the side where the top plate portion 31 is located. The relay side surface 48 faces the side opposite to the relay side surface 47 in the width direction of the leg portion 32. And, the relay side surface 48 is arranged away from the relay side surface 47 in the width direction of the leg portion 32. For the cross-sectional shape changing portion 37, the dimension between the relay side surfaces 47 and 48 is defined as the dimension in the width direction of the leg portion 32 (the width direction of the top plate portion 31).

[0045] Here, for the top plate portion 31, the dimension (width) in the width direction is uniform or substantially uniform at the dimension (first dimension) W1 from the extension end E1 to the extension end E2. Furthermore, for the leg portion 32, the dimension (width) in the width direction (the width direction of the top plate portion 31) is uniform or substantially uniform at the dimension W1 between the leg connection portion 35 and the cross-sectional shape changing portion 37. Therefore, the dimension of the leg portion 32 in the width direction between the leg connection portion 35 and the cross-sectional shape changing portion 37 is consistent or substantially consistent with the dimension of the top plate portion 31 in the width direction. Furthermore, at the bending position of the leg portion 32 relative to the top plate portion 31, the leg portion 32 is the same or substantially the same size as the dimension (first dimension) W1 in the width direction of the top plate portion 31 (the width direction of the leg portion 32).

[0046] In addition, for the extended portion 36, the size (width) of the foot 32 in the width direction (the width direction of the top plate portion 31) is uniformly or approximately uniformly a size (second size) W2 that is smaller than the size (first size) W1. Therefore, for the extended portion 36, the distance between the side surfaces 43 and 44 is the same or approximately the same size as the size W2. For the cross-sectional shape changing portion 37, the closer to the extended portion 36, the smaller the size of the foot 32 in the width direction (the width direction of the top plate portion 31). That is, for the cross-sectional shape changing portion 37 as the width changing portion, the closer to the extended portion 36, the more the size of the foot 32 in the width direction decreases from the size W1 to the size W2. Therefore, for the cross-sectional shape changing portion 37, the closer to the extended portion 36, the smaller the size (distance) between the relay side surfaces 47 and 48.

[0047] For the top plate portion 31, the dimension (thickness) in the thickness direction is uniform or substantially uniform at the dimension (third dimension) T1 from the extended end E1 to the extended end E2. Furthermore, for the leg portion 32, the dimension (thickness) in the thickness direction (the intersecting direction of the connecting lead 20) is uniform or substantially uniform at the dimension T1 between the leg connection portion 35 and the cross-sectional shape changing portion 37. Therefore, the dimension of the leg portion 32 in the intersecting direction of the connecting lead 20 between the leg connection portion 35 and the cross-sectional shape changing portion 37 is consistent or substantially consistent with the dimension of the top plate portion 31 in the thickness direction. Furthermore, at the bending position of the leg portion 32 relative to the top plate portion 31, the leg portion 32 is the same or substantially the same size as the dimension (third dimension) T1 in the thickness direction of the leg portion 32.

[0048] In addition, for the extended portion 36, the size (thickness) of the foot 32 in the thickness direction (the direction intersecting the connecting lead 20) is uniform or substantially uniform, and is a size (fourth size) T2 that is larger than the size (third size) T1. Therefore, for the extended portion 36, the distance between the main surfaces 41 and 42 is the same or substantially the same as the size T2. For the cross-sectional shape changing portion 37, the closer to the extended portion 36, the larger the size of the foot 32 in the thickness direction (the direction intersecting the connecting lead 20). That is, for the cross-sectional shape changing portion 37 as the size changing portion (thickness changing portion), the closer to the extended portion 36, the more the size of the foot 32 in the thickness direction increases from the size T1 to the size T2. Therefore, for the cross-sectional shape changing portion 37, the closer to the extended portion 36, the larger the size (distance) between the relay main surfaces 45 and 46.

[0049] In one example, the dimension W1 is 4.0 mm to 10.0 mm. Moreover, the dimension W2 is -1.0 mm to -7.0 mm relative to the dimension W1. In one example, the dimension T1 is 0.5 mm to 5.0 mm. Moreover, the dimension T2 is +1.0 mm to +5.0 mm relative to the dimension T1.

[0050] In the present embodiment, the main surfaces 41, 42 and the side surfaces 43, 44 are respectively extended in parallel or substantially in parallel with the thickness direction of the top plate portion 31. Furthermore, the relay main surface 45 is extended in a state inclined with respect to the thickness direction of the top plate portion 31, that is, in a state inclined with respect to the main surface 41. The relay main surface 45 is inclined with respect to the main surface 41 in a state that the closer the portion to the extended portion 36 (main surface 41), the farther the relay main surface 46 is from. In addition, the relay main surface 46 is extended in a state inclined with respect to the thickness direction of the top plate portion 31, that is, in a state inclined with respect to the main surface 42. The relay main surface 46 is inclined with respect to the main surface 42 in a state that the closer the portion to the extended portion 36 (main surface 42), the farther the relay main surface 45 is from. Since the relay main surfaces 45, 46 are formed as described above, the size of the leg portion 32 in the thickness direction (the intersecting direction of the connection lead 20) is larger at the portion closer to the extended portion 36 in the cross-sectional shape changing portion 37.

[0051] In addition, the relay side surface 47 is extended in a state of being inclined relative to the thickness direction of the top plate portion 31, that is, in a state of being inclined relative to the side surface 43. The relay side surface 47 is inclined relative to the side surface 43 in a state where the closer the portion is to the extended portion 36 (side surface 43), the closer it is to the relay side surface 48. In addition, the relay side surface 48 is formed parallel or approximately parallel to the thickness direction of the top plate portion 31. Furthermore, no step difference is formed between the relay side surface 48 and the side surface 44, and the relay side surface 48 and the side surface 44 are arranged on the same or approximately the same plane. Since the relay side surfaces 47 and 48 are formed as described above, for the cross-sectional shape change portion 37, the closer the portion is to the extended portion 36, the smaller the size of the foot portion 32 in the width direction (the width direction of the top plate portion 31) is.

[0052] In addition, for the top plate portion 31 of the present embodiment, the hardness is uniform or substantially uniform at the hardness (first hardness) C1 from the extension end E1 to the extension end E2. And, for the leg portion 32, the hardness is uniform or substantially uniform at the hardness C1 between the leg connection portion 35 and the cross-sectional shape changing portion 37. Therefore, the hardness of the leg portion 32 between the leg connection portion 35 and the cross-sectional shape changing portion 37 is consistent or substantially consistent with the hardness of the top plate portion 31. In addition, for the extension portion 36, the hardness of the leg portion 32 is uniform or substantially uniform at the hardness (second hardness) C2 which is harder than the hardness (first hardness) C1. For the cross-sectional shape changing portion 37, the closer to the extension portion 36, the harder the hardness of the leg portion 32. That is, for the cross-sectional shape changing portion 37 as the hardness changing portion, the closer to the extension portion 36, the harder the hardness of the leg portion 32 increases from the hardness C1 to the hardness C2.

[0053] Figure 6 2 is a diagram for explaining an example of a method for manufacturing the connecting lead 20. Figure 6 In one example, the connection lead 20 is formed by one plate member 60. For the plate member 60, the overall dimension (width) in the width direction (plate width direction) is uniform or substantially uniform, which is the dimension W1 described above. Furthermore, for the plate member 60, the overall dimension (thickness) in the thickness direction (plate thickness direction) is uniform or substantially uniform, which is the dimension T1 described above. Furthermore, for the plate member 60, the overall hardness is uniform or substantially uniform, which is the hardness C1 described above.

[0054] The plate member 60 includes portions 61 and 62. In addition, the portion 62 includes regions 63 and 64. When forming the connecting lead 20, the regions 63 and 64 are punched. At this time, the regions 63 and 64 are punched from one side in the width direction of the plate member 60. By the punching process, in the region 63, the dimension (width) in the width direction (plate width direction) is made uniform or substantially uniform to the above-mentioned dimension W2 which is smaller than the dimension W1. Furthermore, in the region 64, the closer to the region 63, the more the dimension of the plate member 60 in the width direction decreases from the dimension W1 to the dimension W2. Furthermore, by the punching process, in the region 63, the dimension (thickness) in the thickness direction (plate thickness direction) is made uniform or substantially uniform to the above-mentioned dimension T2 which is larger than the dimension T1. Furthermore, in the region 64, the closer to the region 63, the more the dimension of the plate member 60 in the thickness direction increases from the dimension T1 to the dimension T2. ​​Therefore, by the punching process, the plate member 60 is made uniform or substantially uniform to the above-mentioned dimension T2 which is larger than the dimension T1. Figure 5 The shape shown by the solid line is deformed into Figure 5 The shape shown by the dotted line.

[0055] In addition, the stamping process of the regions 63 and 64 causes the regions 63 and 64 to be work-hardened. In the region 63, the hardness is uniformly or substantially uniformly the hardness C2 mentioned above, which is harder than the hardness C1. In the region 64, the hardness increases from the hardness C1 to the hardness C2 as it approaches the region 63. In addition, due to the stamping process of the regions 63 and 64, shear surfaces and fracture surfaces may sometimes be generated inside the region 63.

[0056] When the stamping process of the regions 63 and 64 is performed, the portion 62 is bent relative to the portion 61 at the bending position 65 by the bending process. At this time, the portion 62 is bent relative to the portion 61 in a state where the bending line at the bending position 65 is along the width direction of the plate member 60. In addition, the portion 62 is bent relative to the portion 61 toward one side in the thickness direction of the portion 61. In this way, the top plate portion 31 is formed by the portion 61, and the leg portion 32 is formed by the portion 62. In addition, in the portion 62, the region 63 forms the extended portion 36, and the region 64 forms the cross-sectional shape change portion 37.

[0057] In another example, the top plate portion 31 and the leg portion 32 are formed of different members, and the two members are integrated by welding or the like to form the connection lead 20 .

[0058] like Figure 2 and Figure 4 As shown in FIG. 1 , in the internal cavity 8 of the battery 1, the top plate portion 31 of each of the pair of connecting leads 20 is arranged between the electrode group 2 and the electrode pressing member 25 in the height direction of the battery 1, and is clamped between the electrode group 2 and the electrode pressing member 25. For each connecting lead 20, the extending direction (length direction) of the top plate portion 31 is consistent with or substantially consistent with the horizontal direction of the battery 1, and the width direction (plate width direction) of the top plate portion 31 is consistent with or substantially consistent with the longitudinal direction of the battery 1. In addition, for each connecting lead 20, the thickness direction (plate thickness direction) of the top plate portion 31 is consistent with or substantially consistent with the height direction of the battery 1. In the battery 1, the top plate portion 31 of each of the pair of connecting leads 20 is connected to a corresponding one of the electrode terminals 16, that is, a corresponding one of the positive terminal and the negative terminal. For each connecting lead 20, a corresponding one of the electrode terminals 16 is inserted into the through hole 33 of the top plate portion 31. Then, the connection leads 20 are connected to corresponding ones of the electrode terminals 16 by caulking or the like in the through holes 33 .

[0059] In addition, in the internal cavity 8 of the battery 1, the leg portion 32 of each of the pair of connecting leads 20 is arranged between the corresponding one of the side walls 11 and the electrode group 2 in the lateral direction of the battery 1. For each connecting lead 20, the width direction of the leg portion 32 is consistent or substantially consistent with the longitudinal direction of the battery 1, and the thickness direction of the leg portion 32 (the cross direction of the connecting lead 20) is consistent or substantially consistent with the lateral direction of the battery 1. In addition, for each connecting lead 20, the leg portion 32 is arranged outside the through hole 33, that is, the connection position of the corresponding one of the electrode terminals 16 in the lateral direction of the battery 1. Therefore, the top plate portion 31 of each connecting lead 20 is extended toward the outside of the lateral direction of the battery 1 from the corresponding one of the electrode terminals 16 to the connection position (extended end E2) of the leg portion 32.

[0060] In addition, for each connection lead 20, the leg portion 32 is bent relative to the top plate portion 31 toward the side where the bottom wall 6 is located in the height direction of the battery 1. In addition, the bending line of the leg portion 32 relative to the top plate portion 31 is along the longitudinal direction of the battery 1.

[0061] In addition, for each connection lead 20, the corresponding one of the current collector tabs 13B and 14B is connected to the extension portion 36 of the leg portion 32. That is, for each connection lead 20, the joint portion 50 with the corresponding one of the current collector tabs 13B and 14B is formed in the extension portion 36. In the present embodiment, the joint portion 50 is formed on the side surface 43 of the extension portion 36 of each connection lead 20. For each connection lead 20, the side surface 43 of the extension portion 36 faces the corresponding one of the current collector tabs 13B and 14B from one side in the longitudinal direction of the battery 1. In addition, in the present embodiment, the current collector tabs 13B and 14B are connected to the side surface 43 via the backup lead 22, respectively. That is, the current collector tabs 13B and 14B are joined to the side surface 43 in a state where the binding portion 15 is clamped by the backup lead 22, respectively.

[0062] For the connection lead 20 of the present embodiment, the leg 32 is bent relative to the top plate 31 in a state where the bending line at the bending position relative to the top plate 31 is along the width direction of the top plate 31. In addition, the width direction of the leg 32 is consistent or substantially consistent with the width direction of the top plate 31. Therefore, unlike the structure in which the leg is bent relative to the top plate 31 in a state where the bending line is along the extension direction (length direction) of the top plate 31, it is not necessary to form a cutout or the like at the connection position with the leg 32 and its vicinity on the top plate 31. Thus, it is possible to ensure that the cross-sectional area of ​​the top plate 31 is large in the portion connected to the leg 32 and its vicinity, that is, the extension end E2 and its vicinity. Since the cross-sectional area of ​​the top plate 31 is ensured to be large as described above, the resistance of the connection lead 20 can be ensured to be low. Thus, in the current path between each of the collector sheets 13B, 14B and the corresponding one of the electrode terminals 16, it is possible to ensure that the resistance is low.

[0063] In addition, for the connecting lead 20 of the present embodiment, as described above, the bending line of the leg 32 relative to the top plate 31 is along the width direction of the top plate 31. And, for each connecting lead 20 arranged in the internal cavity 8, the bending line of the leg 32 relative to the top plate 31 is along the longitudinal direction of the battery 1. Therefore, even if the electrode group 2 vibrates in the longitudinal direction of the battery 1 (the thickness direction of the electrode group 2) due to the vibration of the battery device mounted on the vehicle, etc., the bending line of the leg 32 relative to the top plate 31 is parallel or approximately parallel to the vibration direction of the electrode group 2. Therefore, even if the electrode group 2 vibrates, each connecting lead 20 is not easily damaged. Therefore, for the connecting lead 20, it is possible to ensure high impact resistance against impacts, etc.

[0064] In addition, in the present embodiment, the extension portion 36 is provided at a position away from the bending position relative to the top plate portion 31 for the leg portion 32. And, for each connection lead 20, a corresponding one of the current collector tabs 13B and 14B is connected to the side surface 43 on one side in the width direction of the top plate portion 31 on the outer surface of the extension portion 36. Therefore, even if the leg portion 32 is bent relative to the top plate portion 31 as described above, the workability of joining the corresponding one of the current collector tabs 13B and 14B to each leg portion 32 of the connection lead 20 can be ensured.

[0065] In addition, for each connection lead 20, a corresponding one of the current collector tabs 13B and 14B is joined to the side surface 43. Therefore, when the electrode group 2 vibrates in the longitudinal direction of the battery 1 (the thickness direction of the electrode group 2), the direction of the force from the electrode group 2 to the connection lead 20 is consistent or substantially consistent with the longitudinal direction of the battery 1. Therefore, the force from the electrode group 2 to the connection lead 20 is applied in the direction along the bending line of the leg portion 32 relative to the top plate portion 31. As a result, the impact resistance of the connection lead 20 to the force from the electrode group 2 is further improved.

[0066] In addition, in the present embodiment, the dimension W2 of the leg portion 32 in the width direction of the extension portion 36 is smaller than the dimension W1 of the leg portion 32 in the width direction of the connection position with the top plate portion 31. Since the dimension W2 of the leg portion 32 in the width direction of the extension portion 36 is reduced, it is easier to join the leg portion 32 of each connection lead 20 to the corresponding one of the current collector tabs 13B and 14B.

[0067] In addition, in the present embodiment, the dimension T2 of the foot portion 32 in the thickness direction of the extension portion 36 is larger than the dimension T1 of the foot portion 32 in the thickness direction of the connection position with the top plate portion 31. Since the dimension T2 of the foot portion 32 in the thickness direction of the extension portion 36 is increased, the surface area of ​​the side surface 43 where each connection lead 20 is joined to the corresponding one of the collector tabs 13B and 14B is increased. Therefore, for the joint 50, the contact area between each connection lead 20 and the corresponding one of the collector tabs 13B and 14B is increased. Therefore, in the current path between each collector tab 13B, 14B and the corresponding one of the electrode terminals 16, it is possible to further appropriately ensure that the resistance is low.

[0068] In addition, in this modification, the cross-sectional shape changing portion 37 gradually decreases in size of the leg portion 32 in the width direction as it approaches the extended portion 36. Therefore, the size of the leg portion 32 in the width direction does not decrease sharply from the size W1 to the size W2. Thus, in the current path between each collector tab 13B, 14B and the corresponding one of the electrode terminals 16, the resistance can be further appropriately ensured to be low.

[0069] (Variation Example)

[0070] In addition, Figure 6 In the variation shown, the dimension (thickness) of the entire connecting lead 20 in the thickness direction is uniform or approximately uniform at dimension T1. Therefore, the dimension of the foot portion 32 in the thickness direction (crossing direction of the connecting lead 20) at the extension portion 36 is the same or approximately the same as the dimension in the thickness direction of the top plate portion 31. In addition, in this variation, the hardness of the entire connecting lead 20 is uniform or approximately uniform at hardness C1. Therefore, the hardness of the foot portion 32 at the extension portion 36 is the same or approximately the same as the hardness of the top plate portion 31.

[0071] In this modification, for the leg 32 of the connection lead 20, the leg connection portion 35 and the extension portion 36 are relayed by the relay portion 52. In addition, in this modification, a step surface 51 is formed at the connection position of the extension portion 36 and the relay portion 52, that is, the boundary position of the extension portion 36 and the relay portion 52. The relay portion 52 has a pair of relay side surfaces 53 and 54. The relay side surface (first relay side surface) 53 faces the side facing the side surface 43 in the width direction of the leg 32. The relay side surface (second relay side surface) 54 is adjacent to the side surface 44 on the side where the top plate portion 31 is located. The relay side surface 54 faces the side opposite to the relay side surface 53 in the width direction of the leg 32. And, the relay side surface 54 is arranged away from the relay side surface 53 in the width direction of the leg 32. In addition, the relay side surfaces 53 and 54 are respectively extended in parallel or substantially parallel to the thickness direction of the top plate portion 31.

[0072] One end of the step surface 51 is connected to the intermediate side surface 53 of the intermediate portion 52, and the other end of the step surface 51 is connected to the side surface 43 of the extended portion 36. The step surface 51 extends from the intermediate side surface 53 to the side surface 43 along the width direction of the foot portion 32 (the width direction of the top plate portion 31). The step surface 51 forms a step difference between the intermediate side surface 53 and the side surface 43. Due to the step difference at the step surface 51, the side surface 43 is arranged on the side where the intermediate side surface 54 and the side surface 44 are located compared to the intermediate side surface 53 in the width direction of the foot portion 32. In addition, no step difference is formed between the intermediate side surface 54 and the side surface 44, and the intermediate side surface 54 and the side surface 44 are arranged on the same or substantially the same plane.

[0073] In this modified example as well, the dimension (width) of the top plate portion 31 in the width direction is uniform or substantially uniform at the dimension (first dimension) W1. Furthermore, for the leg portion 32, the dimension (width) in the width direction (the width direction of the top plate portion 31) is uniform or substantially uniform at the dimension W1 between the leg connecting portion 35 and the stepped surface 51. Therefore, at the bending position of the leg portion 32 relative to the top plate portion 31, the leg portion 32 is the same or substantially the same size as the dimension (first dimension) W1 in the width direction of the top plate portion 31 (the width direction of the leg portion 32). Furthermore, for the extended portion 36, the dimension (width) of the leg portion 32 in the width direction (the width direction of the top plate portion 31) is uniform or substantially uniform at the dimension (second dimension) W2 that is smaller than the dimension (first dimension) W1.

[0074] In this modified example, no press working is performed when forming the extension portion 36 of the connection lead 20. Therefore, the portion forming the extension portion 36 does not undergo work hardening when manufacturing the connection lead 20. In another example, a plate member whose portion forming the extension portion 36 has a smaller width than other portions may be formed by forging.

[0075] In addition, in the above-mentioned embodiments, the outer surface of the leg portion 32 is parallel or substantially parallel to the thickness direction of the top plate portion 31 for the side surface (44, 48 in the first embodiment) on the opposite side of the side where the joint 50 with the collector sheet (13B or 14B) is formed, from the leg connection portion 35 to the protruding end, but is not limited thereto. In a modified example, an inclined surface may be formed on the side surface on the opposite side of the side where the joint 50 with the collector sheet (13B or 14B) is formed in the intermediate portion between the leg connection portion 35 and the extension portion 36. In this case, the inclined surface is inclined relative to the thickness direction of the top plate portion 31 in a state where the closer the portion to the extension portion 36 is, the closer it is to the side surface on the side where the joint 50 is formed.

[0076] In another modified example, a step surface similar to the step surface 51 may be formed on the side opposite to the side where the joint 50 with the collector sheet (13B or 14B) is formed in the intermediate portion between the leg connecting portion 35 and the extended portion 36. In this case, due to the step difference at the step surface, the portion closer to the extended portion 36 is closer to the side where the joint 50 is formed than the portion farther from the extended portion 36.

[0077] In each of the above-mentioned variations, as in the first embodiment, the connection lead 20 includes: a top plate portion 31, and a leg portion 32 bent toward one side of the thickness direction of the top plate portion 31 relative to the top plate portion 31. In addition, the width direction of the leg portion 32 is consistent or substantially consistent with the width direction of the top plate portion 31. Therefore, it is not necessary to form a cutout or the like at the connection position with the leg portion 32 and its vicinity on the top plate portion 31. As a result, it is possible to ensure that the cross-sectional area of ​​the top plate portion 31 is large at the portion connected to the leg portion 32 and its vicinity, that is, at the extended end E2 and its vicinity. Therefore, in each of the variations, it is also possible to ensure that the resistance of the connection lead 20 is low, and it is possible to ensure that the resistance is low in the current path between each of the collector sheets 13B, 14B and the corresponding one of the electrode terminals 16.

[0078] In addition, in each of the above-mentioned modified examples, the bending line of the leg 32 relative to the top plate 31 is along the width direction of the top plate 31. And, for each connecting lead 20 arranged in the internal cavity 8, the bending line of the leg 32 relative to the top plate 31 is along the longitudinal direction of the battery 1. Therefore, in each of the modified examples, even if the electrode group 2 vibrates in the longitudinal direction of the battery 1 (the thickness direction of the electrode group 2), the bending line of the leg 32 relative to the top plate 31 is parallel or approximately parallel to the vibration direction of the electrode group 2. Therefore, even if the electrode group 2 vibrates, each connecting lead 20 is not easily damaged. Therefore, in each of the modified examples, as in the first embodiment, etc., for the connecting lead 20, a high impact resistance against impacts, etc. can be ensured.

[0079] In addition, it is not necessary to make both the positive electrode side connection lead between the positive electrode collector tab 13B and the positive electrode terminal and the negative electrode side connection lead between the negative electrode collector tab 14B and the negative electrode terminal have the same structure as the connection lead 20 in any of the above-mentioned embodiments and modified examples. In other words, it is sufficient that at least one of the positive electrode side connection lead and the negative electrode side connection lead has the same structure as the connection lead 20 in any of the above-mentioned embodiments and modified examples.

[0080] According to at least one of the embodiments or examples, for the connecting lead, the bending line at the bending position relative to the top plate portion is along the width direction of the top plate portion. The leg portion includes an extended portion located away from the bending position relative to the top plate portion, and the extended portion includes a side surface, which faces one side in the width direction of the top plate portion. The side surface of the extended portion is bonded to the collector sheet. Thus, a connecting lead that can ensure high impact resistance and low resistance can be provided.

[0081] Several embodiments of the present invention have been described above, but these embodiments are presented as examples and do not limit the scope of the invention. These new embodiments can be implemented in various other ways, and various omissions, substitutions, and changes can be made without departing from the scope of the invention. These embodiments or their modifications are included in the scope or gist of the invention, and are included in the invention described in the claims and their equivalents.

Claims

1. A connecting lead, which connects a current collector of an electrode group to an electrode terminal in a battery, and comprises: a top plate portion; and a foot portion extending relative to the top plate portion toward one side in the thickness direction of the top plate portion, The foot has: a foot connection portion connected to the top plate portion; An extended portion located away from the top plate portion; and A cross-sectional shape changing portion provided between the leg connecting portion and the extending portion, The leg portion is not bent except for the leg connecting portion, The connecting lead is bent at the leg connecting portion along a bending line along the width direction of the top plate portion, The extension portion comprises: a first main surface, which faces one side of a direction intersecting both the width direction of the top plate portion and the thickness direction of the top plate portion on an outer surface; a second main surface, which faces a side opposite to the first main surface on the outer surface; a first side surface which is intermediate between the first main surface and the second main surface on the outer surface, faces one side in the width direction of the top plate portion, and is joined to the current collector tab; as well as a second side surface which is intermediate between the first main surface and the second main surface on the outer surface and faces the other side in the width direction of the top plate portion, The outer surface of the cross-sectional shape changing portion has: a first relay main surface, which faces the same side as the first main surface; a second relay main surface, which faces the same side as the second main surface; a first relay side surface, which faces the same side as the first side surface; as well as a second intermediate side surface, which faces the same side as the second side surface, The closer the first relay main surface is to the extended portion, the farther it is from the second relay main surface. The closer the first relay side surface is to the extended portion, the closer it is to the second relay side surface.

2. The connecting lead according to claim 1, characterized in that: At the foot connection portion, the foot portion has a first dimension in the width direction of the top plate portion, In the extended portion, the leg portion has a second dimension smaller than the first dimension in the width direction of the top plate portion.

3. The connecting lead according to claim 2, characterized in that: The top plate portion has a third dimension in the thickness direction, In the extended portion, the leg portion has a fourth dimension larger than the third dimension between the first main surface and the second main surface.

4. The connecting lead according to claim 2 or 3, characterized in that: The top plate portion has a first hardness, In the extended portion, the leg portion has a second hardness that is harder than the first hardness.

5. The connecting lead according to any one of claims 1 to 3, characterized in that: The leg portion is provided to extend straightly from the leg connecting portion to a protruding end protruding from the top plate portion.

6. A battery having: The connecting lead according to any one of claims 1 to 5; An outer container having a bottom wall and a peripheral wall, wherein the bottom wall and the peripheral wall define an internal cavity in which the connecting lead is disposed; an electrode group including a positive electrode and a negative electrode, and including a current collector joined to the connecting lead on the side surface of the extending portion of the leg; a cover member mounted on the peripheral wall at an end portion on the side opposite to the bottom wall to close an opening of the internal cavity of the outer container; and An electrode terminal is mounted on the outer surface of the cover member and connected to the top plate portion of the connection lead.

7. The battery according to claim 6, characterized in that The current collector sheet includes: a positive electrode current collector sheet protruding from the electrode group; and a negative electrode current collector sheet protruding in the electrode group to a side opposite to a side where the positive electrode current collector sheet protrudes. The electrode terminal includes a positive terminal and a negative terminal. It is at least one of the following situations, namely: the connecting lead connects the positive electrode collector sheet and the positive electrode terminal; and the connecting lead connects the negative electrode collector sheet and the negative electrode terminal.

Images