JP2014154291A - Battery - Google Patents

Abstract

A battery that can be manufactured at a lower cost than the prior art by devising the arrangement of an electrode body with respect to a battery case.
A battery case includes a battery case from a joining position of a positive electrode internal terminal (11) to an electrode body (position of a welded portion) to a fastening position (position of a fastening portion (19)) of a positive electrode external terminal to a battery case. The distance x along the longitudinal direction of the battery case is from the joining position of the negative electrode internal terminal 61 to the electrode body (position of the weld portion 68) to the fastening position of the negative electrode external terminal 70 to the battery case (position of the fastening portion 69). It is larger than the distance y along the longitudinal direction. Further, the distance a between the positive electrode active material layer non-forming portion 151a (positive electrode end) of the electrode body and the battery case is equal to the separation between the negative electrode active material layer non-forming portion 154a (negative electrode end) of the electrode body and the battery case. It is smaller than the distance b. Thereby, since the copper negative electrode internal terminal can be made smaller than the positive electrode internal terminal, the battery can be manufactured at a low cost while suppressing the material cost.
[Selection] Figure 1

Description

  The present invention relates to a battery in which an electrode body is accommodated in a battery case.

  In recent years, batteries such as lithium ion secondary batteries have been used in various fields such as electronic devices such as mobile phones and personal computers, vehicles such as hybrid cars and electric cars. In particular, a lithium ion secondary battery has a high energy density and is suitable for mounting in various devices.

  As a structure of such a battery, for example, one described in Patent Document 1 below is known. The battery described in Patent Document 1 has a configuration in which an electrode body is accommodated in a flat rectangular battery case (Case 20 of Patent Document 1). The electrode body includes a positive electrode plate (positive electrode sheet 82 of Patent Document 1) having a positive electrode active material layer containing a positive electrode active material, and a negative electrode plate (negative electrode sheet of Patent Document 1) having a negative electrode active material layer containing a negative electrode active material. 84) and a separator are laminated and wound. In this electrode body, one end portion in the winding axis direction is a positive electrode active material layer non-formation portion where no positive electrode active material layer is formed (active material layer non-formation portion of Patent Document 1). The other end is a negative electrode active material layer non-formation part (active material layer non-formation part of patent documents 1) in which the negative electrode active material layer is not formed. A positive electrode terminal is bonded to the positive electrode active material layer non-forming portion, and a negative electrode terminal is bonded to the negative electrode active material layer non-forming portion.

  The positive electrode terminal is provided at one end (inner end) of the electrode body and connected to the positive electrode active material layer non-formation portion of the electrode body by welding, and provided at the other end (outer end). An “exposed portion 68” exposed to the outside of the battery case and a “lead portion 64” extending in the longitudinal direction of the battery case and connecting the connecting portion 62 and the exposed portion 68 (Patent Document) 1 (see FIG. 1). That is, in the positive electrode terminal, the connecting portion 62 is located closer to the end of the battery case than the exposed portion 68 when viewed in the longitudinal direction of the battery case. The negative electrode terminal has the same structure as the positive electrode terminal. The positive electrode terminal and the negative electrode terminal are arranged symmetrically with respect to the center position in the longitudinal direction of the battery case (that is, separated from each other by the same distance).

JP 2008-311014 A

  By the way, depending on the performance required for the battery to be manufactured, the length dimension along the winding axis direction of the electrode body may be small. In particular, with the advancement of technology, it is considered that even an electrode body having the same rated capacity can be manufactured smaller. Thus, even when a battery is manufactured using a small electrode body (an electrode body having a small length along the winding axis direction), from the viewpoint of manufacturing cost reduction, parts such as a battery case are sized. It is desirable to use a conventional one without changing. Therefore, in such a case, there is room for improvement as to how the electrode body is arranged with respect to the battery case. This is because the cost can be cut depending on the arrangement. However, in Patent Document 1, the positive electrode terminal and the negative electrode terminal have the same shape, and are assembled to the battery case so as to be symmetrical with respect to the center position in the longitudinal direction, so that the electrode body is not displaced from the battery case. Only the configuration to be arranged is described.

  The present invention has been made in view of the above circumstances. That is, the problem is to provide a battery that can be manufactured at a lower cost than before by devising the arrangement of the electrode body with respect to the battery case.

  The battery of the present invention, which has been made for the purpose of solving this problem, has an electrode body formed by winding a positive electrode plate and a negative electrode plate with a separator interposed therebetween, and a flat rectangular battery that accommodates the electrode body therein. The case, the aluminum positive electrode internal terminal joined to the positive electrode end of the electrode body, and the electrical connection to the positive electrode internal terminal, and the fastening to the battery case to the outside of the battery case The positive electrode external terminal arranged, the copper negative electrode internal terminal joined to the negative electrode end of the electrode body, and the electric connection to the negative electrode internal terminal and the fastening to the battery case A negative electrode external terminal disposed outside the battery case, and the positive electrode external terminal and the negative electrode external terminal are disposed symmetrically with respect to a central position along the longitudinal direction of the battery case. Further, in this battery, the distance along the longitudinal direction of the battery case from the joining position of the positive electrode internal terminal to the electrode body to the fastening position of the positive electrode external terminal to the battery case is determined from the joining position of the negative electrode internal terminal to the electrode body. The distance along the longitudinal direction of the battery case between the positive electrode end of the electrode body and the battery case is greater than the distance along the longitudinal direction of the battery case to the fastening position of the negative electrode external terminal with respect to the negative electrode external terminal. It is smaller than the separation distance along the longitudinal direction of the battery case with the battery case. Here, “made of aluminum” means substantially composed of aluminum or an alloy mainly composed of aluminum (aluminum alloy). “Copper” means substantially composed of copper or an alloy mainly composed of copper (copper alloy).

  In the battery of the present invention, the positive external terminal and the negative external terminal are arranged symmetrically with respect to the center position in the longitudinal direction of the battery case. Then, the electrode body is arranged in the battery case so that the separation distance between the positive electrode end of the electrode body and the battery case along the longitudinal direction of the battery case is smaller than the separation distance between the negative electrode end of the electrode body and the battery case. Is housed inside. When such an electrode body is accommodated, the shapes of the positive electrode internal terminal and the negative electrode internal terminal are differentiated as follows. That is, the amount of deviation between the joining position of the positive electrode internal terminal with respect to the electrode body and the fastening position of the positive electrode external terminal with respect to the battery case when viewed in the longitudinal direction of the battery case, It is configured to be larger than the deviation amount when viewed in the longitudinal direction of the battery case from the fastening position of the negative electrode external terminal with respect to the case. In other words, as compared with the copper negative electrode internal terminal, the aluminum positive electrode internal terminal extends to a position closer to the end of the battery case than the fastening position of the external terminal. Therefore, the amount of material (copper amount) required to form the negative electrode internal terminal is smaller than the configuration of the negative electrode internal terminal in the same shape as the positive electrode internal terminal. Copper constituting the negative electrode internal terminal is a higher cost material than aluminum forming the positive electrode internal terminal. Therefore, according to the present invention, it is possible to reduce the material cost necessary for manufacturing the negative electrode internal terminal which is more expensive than the positive electrode internal terminal, and thus it is possible to manufacture a battery at a low cost.

  Here, the battery of the present invention includes an insulating film that is interposed between the electrode body and the battery case and insulates the electrode body and the battery case from the one end surface on the positive electrode end side of the electrode body to the one end surface. The distance to the inner surface of the opposing insulating film is preferably smaller than the distance from the other end surface on the negative electrode end side of the electrode body to the inner surface of the insulating film facing the other end surface.

  If comprised in this way, the clearance gap between the negative electrode edge part of an electrode body and an insulating film will become larger than the clearance gap between the positive electrode edge part of an electrode body, and an insulation film. Therefore, compared with the case where the gap between the negative electrode end of the electrode body and the insulating film is configured to have the same size as the positive electrode side, the negative electrode internal terminal and the negative electrode end of the electrode body are prevented from contacting the insulating film. Can do. Therefore, even if the battery is exposed to a high temperature or deteriorates over time, it is possible to prevent copper ions from entering the insulating film from the negative electrode internal terminal or the negative electrode end of the electrode body. Therefore, the insulation by an insulating film can be maintained.

  Further, in the battery of the present invention, the battery case is provided with a liquid injection port for injecting the electrolyte into the battery case at a position offset from the center position along the longitudinal direction to the positive electrode external terminal side. It is desirable.

  In the battery configured as described above, since the liquid injection port is offset toward the positive electrode external terminal side, the negative electrode end of the electrode body and the negative electrode internal terminal are far from the liquid injection port, and the electrolyte penetrates accordingly. It becomes difficult to do. However, in the present invention, the separation distance between the negative electrode end of the electrode body and the battery case is longer than the separation distance between the positive electrode end of the electrode body and the battery case. That is, the gap between the negative electrode end and the battery case is wider than the positive electrode side. Therefore, the electrolyte injected into the battery case tends to spread to the negative electrode end side. Therefore, the electrolyte can be sufficiently permeated into the negative electrode end portion side of the electrode body.

  According to the present invention, there is provided a battery that can be manufactured at a lower cost than before by devising the arrangement of the electrode body with respect to the battery case.

It is sectional drawing which shows the battery which concerns on embodiment. It is a figure which shows the structure of the electrode body with which the battery is equipped. It is a disassembled perspective view which shows the positive electrode terminal member with which the battery is equipped. It is a disassembled perspective view which shows the negative electrode terminal member with which the battery is equipped. It is a perspective view which shows the insulator with which a positive electrode terminal member and a negative electrode terminal member are provided. It is a perspective view which shows the state which assembled | attached the positive electrode terminal member provided with the insulator which concerns on a prior art to a sealing lid. It is sectional drawing which shows the battery which concerns on a prior art. It is an end view which shows typically the electrode body seen from the positive electrode active material layer non-formation part side.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. As shown in FIG. 1, the battery 100 according to the present embodiment includes a flat rectangular parallelepiped (that is, rectangular) battery case 110 and an electrode body 150 accommodated in the battery case 110. It is. The battery 100 is mounted on a vehicle such as a hybrid car or an electric vehicle, or a battery using device such as a hammer drill. In this specification, unless otherwise specified, the top, bottom, left, and right refer to FIG. 1, and the front side of the page in FIG. 1 is the front and the back side of the page is the back.

The electrode body 150 is a wound electrode body 150 in which a belt-like positive electrode plate 151 and a negative electrode plate 154 are wound with a belt-like separator 157 interposed therebetween and crushed into a flat shape. The electrode body 150 is housed inside the battery case 110 in a posture in which the winding shaft is laid down (that is, in a state where the winding shaft is aligned in the horizontal direction). The electrode body 150 is impregnated with an electrolytic solution. The electrolytic solution is, for example, ethylene carbonate (EC), dimethyl carbonate (DMC), and ethyl methyl carbonate (EMC) in a volume ratio of EC: DMC: EM.
This is a nonaqueous electrolytic solution in which lithium hexafluorophosphate (LiPF ₆ ) is added as a solute to a mixed organic solvent adjusted to C = 30: 40: 30, and the lithium ion concentration is 1 mol / l.

  FIG. 2 is a diagram showing the structure of the electrode body 150. As shown in FIG. 2, the positive electrode plate 151 has a positive electrode active material layer 153 disposed on a belt-like positive electrode base material (positive electrode foil) 152 made of an aluminum foil extending along the longitudinal direction DA (vertical direction in FIG. 2). Is. The positive electrode active material layer 153 includes a positive electrode active material (for example, lithium cobaltate), a conductive material (for example, acetylene black), and a binder (for example, PVDF).

  The negative electrode plate 154 is obtained by disposing a negative electrode active material layer 156 on a strip-shaped negative electrode substrate (negative electrode foil) 155 made of a copper foil extending along a longitudinal direction DA (vertical direction in FIG. 2). The negative electrode active material layer 156 includes a negative electrode active material (for example, natural graphite), a binder (for example, SBR), and a thickener (for example, CMC). The separator 157 is made of a porous polyolefin resin. The separator 157 is interposed between the positive electrode plate 151 and the negative electrode plate 154 to insulate them.

  Here, in the electrode body 150, the positive electrode plate 151 and the negative electrode plate 154 are shifted along the width direction (winding axis direction), and one end of the positive electrode plate 151 protrudes from one end in the width direction of the separator 157. The other end of the negative electrode plate 154 is wound so as to protrude from the other end in the width direction. The protruding portion of the positive electrode plate 151 is a positive electrode active material layer non-forming portion 151a (corresponding to the positive electrode end portion) where the positive electrode active material layer 153 is not formed. The positive electrode active material layer non-forming portion 151a is located at an end portion (left end portion in FIG. 2) in the width direction DB (left and right direction in FIG. 2) of the positive electrode base material 152 (positive electrode plate 151). Further, the protruding portion of the negative electrode plate 154 is a negative electrode active material layer non-forming portion 154a (corresponding to the negative electrode end portion) where the negative electrode active material layer 156 is not formed. The negative electrode active material layer non-forming portion 154a is located at the end portion (right end portion in FIG. 2) of the negative electrode base material 155 (negative electrode plate 154) in the width direction DB.

  As shown in FIG. 1, the battery case 110 includes a case main body member (battery case main body) 111 and a sealing lid (battery case lid) 113. The battery case 110 is made of metal (specifically, pure aluminum). The case body member 111 has a bottomed rectangular box shape having an opening 111d at the top. More specifically, the case main body member 111 includes a rectangular plate-like case bottom wall portion 111b facing the sealing lid 113, and four case side wall portions 111c erected upward from the periphery of the case bottom wall portion 111b. ing. Further, the case body member 111 has a flat shape with a long left-right direction and a short front-back direction.

  The sealing lid 113 is formed in a rectangular plate shape that fits into the opening 111 d of the case body member 111. The sealing lid 113 is welded to the case main body member 111 on the entire circumference in a state where the opening 111 d of the case main body member 111 is closed. At both ends in the longitudinal direction (left-right direction) of the sealing lid 113, circular through holes 113h and 113k penetrating the sealing lid 113 are formed. The through hole 113h is a terminal lead hole through which a part of a positive electrode terminal member 10 described later is inserted, and the through hole 113k is a terminal lead hole through which a part of a negative electrode terminal member 60 described later is inserted.

  In addition, a safety valve 113j is provided at the center of the sealing lid 113 in the longitudinal direction. The safety valve 113j is formed integrally with the sealing lid 113 and forms a part of the sealing lid 113. The safety valve 113j is formed thinner than the other part of the sealing lid 113, and a groove 113jv is formed on the upper surface thereof. As a result, the safety valve 113j operates when the internal pressure inside the battery case 110 reaches a predetermined pressure. That is, when the internal pressure reaches a predetermined pressure, the groove 113jv breaks, and the gas inside the battery case 110 is released to the outside.

  In addition, a liquid injection port 113n for injecting the electrolytic solution into the battery case 110 is formed between the safety valve 113j of the sealing lid 113 and the through hole 113h. The liquid injection port 113n is sealed with a liquid injection plug 113m.

  The positive electrode terminal member 10 is joined to the positive electrode active material layer non-forming portion 151a by ultrasonic welding. Moreover, the negative electrode terminal member 60 is joined to the negative electrode active material layer non-forming portion 154a by resistance welding. The positive electrode terminal member 10 and the negative electrode terminal member 60 are connected to the electrode body 150 inside the case main body member 111 and extend to the outside through the through holes 113 h and 113 k of the sealing lid 113.

  The positive electrode terminal member 10 includes a positive electrode internal terminal 11, a positive electrode external terminal 20, a positive electrode fastening bolt 30, a gasket 34, and an insulator 36. The positive electrode internal terminal 11 is made of metal (pure aluminum) and is mainly located inside the battery case 110. The positive electrode internal terminal 11 passes through the through hole 113 h of the sealing lid 113, and the positive electrode external terminal 20, the insulator 36 and the gasket 34 are caulked to the sealing lid 113. Thereby, the positive electrode internal terminal 11 is electrically connected to the positive electrode external terminal 20.

  Specifically, as shown in FIGS. 1 and 3, the positive electrode internal terminal 11 has a rectangular plate-like pedestal portion 12 extending in the horizontal direction and a cylindrical shape protruding from the upper surface of the pedestal portion 12, and is inserted into the through hole 113h. The battery case 110 is connected to the battery case 110 from the insertion part 13, the upper part of the insertion part 13, and the caulking part 14 that is caulked (deformed so as to expand in diameter) to form a disk shape, and the lower surface of the pedestal part 12. And an electrode body connection portion 17 that extends toward the case bottom wall portion 111b and is welded to the positive electrode active material layer non-forming portion 151a.

The electrode body connecting portion 17 includes a first lead portion 17a extending along the vertical direction and a second lead portion extending obliquely to the right from the bottom to the top and connecting the upper end of the first lead portion 17a and the pedestal portion 12. 17b. A lower portion of the first lead portion 17a is a welded portion 18 joined to the positive electrode active material layer non-formed portion 151a by ultrasonic welding. Since the electrode body connecting portion 17 has the second lead portion 17b, the positive electrode terminal member 10 includes a welded portion 18 to the electrode body 150, a fastening portion 19 (location of the insertion portion 13) to the sealing lid 113, and However, they are separated by a distance x when viewed in the left-right direction (longitudinal direction of the battery case 110).

  The caulking portion 14 before caulking deformation has a cylindrical shape as shown in FIG. When the battery is manufactured, the gasket 34, the sealing lid 113, the insulator 36, and the positive electrode external terminal 20 are inserted in this order together with the insertion portion 13, and the tip portion (the portion that becomes the caulking portion 14) is inserted from the positive electrode external terminal 20. The battery case 110 is protruded outside. Then, the caulking portion 14 is plastically deformed by expanding the diameter so as to push it wide. As a result, the positive external terminal 20 is caulked and fixed to the sealing lid 113 via the insulator 36.

  The positive electrode external terminal 20 is made of metal (aluminum) and is located on the sealing lid 113 (outside of the battery case 110). The positive external terminal 20 has a substantially Z shape when viewed from the front. The positive electrode external terminal 20 includes a fixing portion 21 fixed by the caulking portion 14, a connecting portion 22 that connects to the positive electrode fastening bolt 30, and a connecting portion 23 that connects the fixing portion 21 and the connecting portion 22. Yes. The fixing portion 21 is formed with a through hole 21a penetrating therethrough. The insertion portion 13 of the positive electrode internal terminal 11 is inserted into the through hole 21a. Further, the connecting portion 22 is also formed with a through hole 22a penetrating therethrough.

  The positive electrode fastening bolt 30 is for fastening a bus bar for connecting a plurality of batteries 100 when a plurality of batteries 100 are used to form an assembled battery. Specifically, the positive electrode fastening bolt 30 is made of metal, and has a rectangular plate-shaped head portion 31 and a columnar shaft portion 32. A portion on the tip side of the shaft portion 32 is a screw portion 32a. The shaft portion 32 of the positive electrode fastening bolt 30 is inserted into the through hole 22 a of the positive electrode external terminal 20. When manufacturing the assembled battery, the bus bar can be fixed to the positive electrode external terminal 20 by further inserting the bus bar into the shaft portion 32 inserted into the positive electrode external terminal 20 and tightening the nut.

  The gasket 34 is made of an electrically insulating resin (for example, PFA) and is interposed between the negative electrode internal terminal 11 and the sealing lid 113 to electrically insulate them. The insulator 36 is made of an electrically insulating resin (for example, 100% PPS), and is interposed between the negative electrode external terminal 20 and the sealing lid 113 to electrically insulate them.

  Specifically, as shown in FIG. 5, the insulator 36 includes a bolt holding portion 37 that holds the head portion 31 of the positive fastening bolt 30, and an external terminal holding portion 38 that holds the fixing portion 21 of the negative external terminal 20. Have The external terminal holding portion 38 includes a seat portion 39 on which the fixing portion 21 of the negative electrode external terminal 20 is placed, and in contact with the lower surface of the fixing portion 21, and a peripheral wall portion 40 erected upward from the periphery of the seat portion 39. Two notches 42 are provided in both the wall portions 40a and 40b in the longitudinal direction of the peripheral wall portion 40, respectively. The notch 42 has a shape in which the peripheral wall 40 is thinned along the inner and outer directions. The bottom surface of the notch 42 and the seat surface of the seat 39 are flush with each other. The seat portion 39 is provided with a through hole 39a for inserting the insertion shaft 13 of the positive electrode internal terminal 11.

  The reason why the notch 42 is formed in the insulator 36 is as follows. FIG. 6 shows a sealing lid 113 assembled with an insulator 36A according to the prior art. The insulator 36A according to the related art does not have the notch portion 42 (see FIG. 5). In FIG. 6, the configuration is the same as that of the battery 100 of this embodiment except for the insulator 36A. When the positive electrode terminal member 10A is assembled to the sealing lid 113, the cylindrical caulking portion 14 of the positive electrode internal terminal 11 is caulked so as to be expanded in diameter using a rotary caulking machine. The rotary caulking machine expands the caulking portion 14 of the positive electrode internal terminal 11 by rotating a jig having a rotation axis (see axis n shown in FIG. 6) along the vertical direction (see arrow m in FIG. 6). . At this time, the rotational force applied to the caulking portion 14 by the rotary caulking machine (moment with the axis n shown in FIG. 6 as the rotation axis) is also applied to the positive external terminal 20 in contact with the caulking portion 14. That is, when the positive electrode internal terminal 11 is caulked, a moment in the same direction as the rotation direction of the jig of the rotary caulking machine is applied to the positive electrode external terminal 20.

  Here, the insulator 36 </ b> A disposed between the positive electrode external terminal 20 and the sealing lid 113 is provided with a peripheral wall portion 40 </ b> A that surrounds the fixing portion 21 of the positive electrode external terminal 20. Therefore, when a moment is applied to the positive electrode external terminal 20 as described above, the insulator 36A that holds the positive electrode external terminal 20 by the peripheral wall portion 40A (the insulator 36A that restricts the rotation of the positive electrode external terminal 20 by the peripheral wall portion 40A). ) Stress occurs. As a result, the insulator 36A may break. The insulator 36A is a component that requires a certain rigidity because it is caulked between the positive electrode external terminal 20 and the sealing lid 113. Therefore, it is weak against stress in the rotational direction.

  In order to prevent this problem, in the embodiment, the insulator 36 is provided with a notch 42 (see FIG. 5). According to such a configuration, the stress generated in the insulator 36 due to the moment during caulking of the positive electrode internal terminal 11 is dispersed. Therefore, the insulator 36 can be prevented from cracking. In the embodiment, four cutout portions 42 are provided, but at least one cutout portion 42 may be provided.

  As shown in FIGS. 1 and 4, the negative electrode terminal member 60 includes a negative electrode internal terminal 61, a negative electrode external terminal 70, a negative electrode fastening bolt 80, a gasket 84, and an insulator 86. The negative external terminal 70, the negative fastening bolt 80, the gasket 84, and the insulator 86 are substantially the same as the positive external terminal 20, the positive fastening bolt 30, the gasket 34, and the insulator 36, and thus description thereof is omitted. . However, the negative electrode external terminal 70 is not made of aluminum but made of copper. The gasket 84 is interposed between the negative electrode internal terminal 61 and the sealing lid 113 and electrically insulates them. Further, the insulator 86 is interposed between the negative electrode external terminal 70 and the sealing lid 113 and electrically insulates them.

  The negative electrode internal terminal 61 is made of metal (pure copper) and is mainly located inside the battery case 110. The negative electrode internal terminal 61 passes through the through hole 113 k of the sealing lid 113, and the negative electrode external terminal 70, the insulator 86 and the gasket 84 are caulked to the sealing lid 113. Thereby, the negative electrode internal terminal 61 is electrically connected to the negative electrode external terminal 70.

  Specifically, the negative electrode internal terminal 61 includes a rectangular plate-like pedestal portion 62 extending in the horizontal direction, a columnar shape protruding from the upper surface of the pedestal portion 62, an insertion portion 63 inserted through the through hole 113 k, and an insertion portion 63 is connected to the upper end of 63, and is caulked (deformed so as to expand in diameter) to form a disk shape, and extends from the lower surface of the pedestal 62 to the case bottom wall 111b side of the battery case 110, And an electrode body connection portion 67 welded to the negative electrode active material layer non-forming portion 154a.

  The electrode body connection portion 67 extends vertically downward from the pedestal portion 62 along the vertical direction. The lower part of the electrode body connection part 67 is a welded part 68 welded to the negative electrode active material layer non-forming part 154a. In the negative electrode terminal member 60, the welded portion 68 to the electrode body 150 and the fastening portion 69 (location of the insertion portion 63) to the sealing lid 113 are hardly separated in the left-right direction (longitudinal direction of the battery case 110). (At approximately the same position). In this embodiment, if the distance between the welded portion 68 of the negative electrode terminal member 60 to the electrode body 150 and the fastening portion 69 (location of the insertion portion 63) to the sealing lid 113 is y, x> y in this embodiment. The positive terminal member 10 and the negative terminal member 60 are configured so as to hold.

  The caulking portion 64 before caulking deformation has a cylindrical shape as shown in FIG. When the battery is manufactured, the gasket 84, the sealing lid 113, the insulator 86, and the negative electrode external terminal 70 are inserted in this order together with the insertion portion 63, and the tip portion (the portion that becomes the caulking portion 64) is inserted from the negative electrode external terminal 70. The battery case 110 is protruded outside. Then, the caulking portion 64 is plastically deformed by expanding the diameter so as to push it wide. As a result, the negative external terminal 70 is caulked and fixed to the sealing lid 113 via the insulator 86. The insulator 86 is the same as the insulator 36 (having a notch). Therefore, when the negative electrode internal terminal 61 is caulked to the sealing lid 113, unlike the conventional insulator 36A (see FIG. 6), it does not break.

  In the present embodiment, the positive terminal member 10 and the negative terminal member 60, the gaskets 34 and 84, and the insulators 36 and 86 are assembled to the sealing cover 113, whereby the terminal cover member 115 (see FIG. 1) is obtained. It is configured. Specifically, the positive electrode external terminal 20, the insulator 36, the sealing lid 113, and the gasket 34 are sandwiched and fixed between the caulking portion 14 provided on the positive electrode terminal member 10 and the pedestal portion 12, and the negative electrode terminal By attaching and fixing the negative electrode external terminal 70, the insulator 86, the sealing lid 113, and the gasket 84 between the caulking portion 64 provided on the member 60 and the pedestal portion 62, the terminal is integrated. A lid member 115 is formed. In the terminal cover member 115, the positive external terminal 20 and the negative external terminal 70 are arranged symmetrically with respect to the longitudinal center position O (see FIG. 1) of the sealing cover 113.

  As shown in FIG. 1, the battery 100 includes an insulating film 170 for insulating the electrode body 150 and the battery case 110. The insulating film 170 is made of an olefin resin, specifically, polypropylene in the embodiment. The insulating film 170 may be made of a resin such as polyimide, aromatic polyamide, phenol resin, polyethylene terephthalate, fluorine resin, polyamide resin, or paper.

  In the manufacturing process of the battery 100, the insulating film 170 is attached so as to wrap the electrode body 150 with respect to the positive electrode terminal member 10 and the negative electrode terminal member 60 assembled to the sealing lid 113 and the electrode body 150 joined thereto. In a state where the electrode body 150 is housed in the battery case 110, the insulating film 170 is interposed between the electrode body 150 and the battery case 110. In this state, the distance between the insulating film 170 and the battery case 110 is substantially the same on the positive electrode side (left side in FIG. 1) and on the negative electrode side (right side in FIG. 1). More specifically, the insulating film 170 has a bottom wall portion 171 and four side wall portions 172, has a bottomed box shape with only the upper side opened, and the electrode body 150 is removed except for the upper side. Surrounds the whole.

  Here, in the present embodiment, the electrode body 150 is located offset to the positive electrode side. Specifically, as shown in FIG. 1, the positive electrode side end surface 150a of the electrode body 150 (the end surface orthogonal to the winding axis, which corresponds to “one end surface”) and the battery case 110 facing the positive electrode side end surface 150a. The distance a between the left inner surface 110a and the right side of the battery case 110 facing the negative electrode side end surface 150b and the negative electrode side end surface 150b of the electrode body 150 (the end surface orthogonal to the winding axis, corresponding to the “other end surface”). The electrode body 150 is disposed in the battery case 110 so as to be smaller than the separation distance b from the inner surface 110b (in other words, a <b). Therefore, the separation distance c between the positive electrode side end surface 150a of the electrode body 150 and the left inner surface 170a of the insulating film 170 facing the positive electrode side end surface 150a is opposite to the negative electrode side end surface 150b of the electrode body 150 and the negative electrode side end surface 150b. It is smaller than the separation distance d from the right inner surface 170b of the insulating film 170 (in other words, c <d).

  Such a displacement of the electrode body 150 is such that the welded portion 18 of the positive electrode internal terminal 11 with respect to the electrode body 150 is more along the longitudinal direction of the battery case 110 than the welded portion 68 of the negative electrode internal terminal 61 with respect to the electrode body 150. This is realized by being provided at a position closer to the outside of the battery case 110. As shown in FIG. 7, the negative electrode internal terminal 61A is also configured similarly to the positive electrode internal terminal 11 (that is, the negative electrode internal terminal 61A of the negative electrode terminal member 60A is the first lead portion having the same shape as the first lead portion 17a). 67Aa and the second lead portion 67Ab having the same shape as the second lead portion 17b), and the electrode body 150 is arranged in the center of the battery case 110 without being offset from the battery case 110 (In other words, when arranged so that x = y), the relationship between the electrode body 150 and the battery case 110 is as follows. That is, as shown in FIG. 7, the separation distance e between the positive electrode side end surface 150a of the electrode body 150 and the left inner surface 110a of the battery case 110 facing the positive electrode side end surface 150a is equal to the negative electrode side end surface 150b of the electrode body 150. , It is the same as the separation distance f between the negative inner side surface 150b and the right inner surface 110b of the battery case 110 facing (in other words, e = f). Therefore, the separation distance g between the positive electrode side end surface 150a of the electrode body 150 and the left inner surface 170a of the insulating film 170 facing the positive electrode side end surface 150a is also opposed to the negative electrode side end surface 150b and the negative electrode side end surface 150b of the electrode body 150. It becomes the same as the separation distance h from the right inner surface 170b of the insulating film 170 to be performed (in other words, g = h).

  When the electrode assembly 150 is disposed as shown in FIG. 7, the negative electrode internal terminal 61A is located outside the battery case 110 in the longitudinal direction (closer to the end of the battery case) than the battery 100 (see FIG. 1) of the present embodiment. ). Therefore, the amount of material necessary to make the negative electrode internal terminal 61A is increased accordingly. However, in the battery 100 of the present embodiment, the negative electrode internal terminal 61 is not located outside the longitudinal direction of the battery case 110 (see FIG. 1). In other words, the electrode body connecting portion 67 is not curved to the outside of the battery case 110 and extends straight from the pedestal portion 62 along the vertical direction. Therefore, according to the battery 100 of the embodiment, the negative electrode internal terminal 61 can be manufactured with less copper than when the battery is manufactured with the configuration shown in FIG. As a result, the battery 100 can be manufactured at a low cost.

  When the electrode body 150 is arranged as shown in FIG. 7, the negative electrode side end surface 150b of the electrode body 150 is closer to the right inner surface 170b of the insulating film 170 than the battery 100 (see FIG. 1) of this embodiment. Be placed. In such an arrangement, when the battery is exposed to a high temperature as it is used or deteriorates over time, the negative electrode internal terminal 61A made of copper and the negative electrode base material 155 are in contact with the insulating film 170, Copper ions sometimes entered the insulating film 170. When copper ions permeate into the insulating film 170, the insulating properties of the insulating film 170 deteriorate. In particular, when the insulating film 170 is an olefin-based resin (particularly polypropylene), the insulating properties are remarkably lowered due to the penetration of copper ions.

  However, if configured like the battery 100 of this embodiment, the negative electrode side end surface 150b of the electrode body 150 can be disposed sufficiently away from the right inner surface 170b of the insulating film 170. Therefore, in the battery 100 of the embodiment, copper ions are difficult to penetrate into the insulating film 170. As a result, the insulating property of the insulating film 170 can be maintained. That is, it is possible to prevent the occurrence of a problem that the insulating property of the insulating film 170 is lowered.

  Further, as in the embodiment, when the separation distance from the battery case 110 to the insulating film 170 is the same on both the positive electrode side and the negative electrode side, the negative electrode side end surface 150b of the electrode body 150 and the right inner surface 170b of the insulating film 170 The separation distance d (see FIG. 1) is preferably larger than twice the separation distance between the insulating film 170 and the battery case 110. This is because the insulating film 170 does not contact the negative electrode side end face 150b of the electrode body 150 even when the insulating film 170 moves to the positive electrode side.

  Further, in the present embodiment, the position of the liquid injection port 113n provided in the sealing lid 113 is more positive than the central position along the winding axis direction (left-right direction) in the wound electrode body 150, as shown in FIG. The terminal member 10 is offset toward the welded portion 18 side. In other words, the welded portion 18 of the positive electrode terminal member 10 is closer to the liquid injection port 113 n than the welded portion 68 of the negative electrode terminal member 60, and the welded portion 68 of the negative electrode terminal member 60 is closer to the welded portion 18 of the positive electrode terminal member 10. It is located far from the liquid injection port 113n.

  As described above, when the position of the liquid injection port 113n is offset from the welded portion 18 of the positive electrode terminal member 10, the positive electrode active material layer non-forming portion 151a is easily impregnated with the electrolyte, and the negative electrode active material layer non-forming portion is formed. It becomes difficult for 154a to be impregnated with the electrolytic solution. However, in the present embodiment, the distance between the electrode body 150 and the battery case 110 is larger on the negative electrode side far from the liquid injection port 113n than on the positive electrode side near the liquid injection port 113n (a <b). . That is, the negative electrode side end surface 150b of the electrode body 150 is located closer to the liquid injection port 113n than when the electrode body 150 is disposed symmetrically at the center position of the battery case 110 (see FIG. 7). Therefore, the impregnation property of the electrolytic solution into the negative electrode active material layer non-forming portion 154a of the electrode body 150 is improved. Therefore, the electrode body 150 can be sufficiently impregnated with the electrolytic solution.

  In the embodiment, the positive electrode active material layer non-forming portion 151a near the liquid injection port 113n is obtained by winding the positive electrode base material 152 that is an aluminum foil, and the negative electrode active material layer non-forming portion far from the liquid injection port 113n. 154a is obtained by winding a negative electrode substrate 155 which is a copper foil. Here, of aluminum and copper, copper has higher conductivity. Therefore, the negative electrode base material 155 that is a copper foil can be manufactured thinner than the positive electrode base material 152 that is an aluminum foil. Thus, when the negative electrode base material 155 is manufactured to be thinner than the positive electrode base material 152, the positive electrode active material layer non-forming portion 151 a of the electrode body 150 is thicker than the positive electrode base material 152. The gap (see FIG. 8) becomes denser than the negative electrode active material layer non-forming portion 154a. On the other hand, the negative electrode active material layer non-forming portion 154a of the electrode body 150 has a thinner gap between the negative electrode internal terminals 61 after welding (see FIG. 8) than the positive electrode active material layer non-forming portion 151a because the negative electrode base material 155 is thin. become. The dense positive electrode active material layer non-forming portion 151a has a lower electrolyte impregnation property than the negative electrode active material layer non-forming portion 154a. However, in the battery 100 of the present embodiment, since the liquid injection port 113n is located closer to the positive electrode active material layer non-forming portion 151a, the impregnation property of the electrolyte into the positive electrode active material layer non-forming portion 151a is improved. Can be made. Therefore, the electrode body 150 can be sufficiently impregnated with the electrolytic solution. FIG. 8 is an end view schematically showing the electrode body 150 as viewed from the positive electrode active material layer non-forming portion 151a side, but also shows components on the negative electrode side with parentheses.

  Next, the manufacturing process of the battery 100 of this embodiment will be briefly described. First, the electrode body 150, the case main body member 111, and the terminal cover member 115 configured as described above are prepared (manufactured).

  Next, as shown in FIG. 1, the positive electrode terminal member 10 is joined to the positive electrode active material layer non-forming portion 151a of the electrode body 150 by ultrasonic welding. Furthermore, the negative electrode terminal member 60 is joined to the negative electrode active material layer non-forming portion 154a of the electrode body 150 by resistance welding. Thereby, the terminal cover member 115 and the electrode body 150 are integrated.

  Subsequently, the insulating film 170 is assembled so as to cover the periphery of the electrode body 150. Then, the electrode body 150 is housed in the case body member 111 together with the insulating film 170, and the case body member 111 is closed by the sealing lid 113. At this time, the positional relationship among the electrode body 150, the insulating film 170, and the battery case 110 is as shown in FIG. That is, the electrode body 150 is arranged in the battery case 110 so as to be offset toward the positive electrode side. Thereafter, the sealing lid 113 and the case body member 111 are joined by laser welding.

  After the sealing lid 113 and the case body member 111 are joined by laser welding, the electrolytic solution is injected into the case body member 111 through the liquid inlet 113n and impregnated in the electrode body 150. Then, the liquid injection port 113n is sealed by inserting the liquid injection plug 113m into the liquid injection port 113n. Thereafter, the battery 100 of this embodiment (see FIG. 1) is completed by performing predetermined processing.

  The battery 100 according to the embodiment can be mounted on a vehicle that uses the electric energy generated by the battery 100 for all or part of a power source. Examples of the “vehicle” include an electric vehicle, a hybrid vehicle, a plug-in hybrid vehicle, a hybrid railway vehicle, a forklift, an electric wheelchair, an electric assist bicycle, and an electric scooter.

  As described above, the battery 100 according to this embodiment includes the electrode body 150 in which the positive electrode plate 151 and the negative electrode plate 154 are wound with the separator 157 interposed therebetween, and the flat body that houses the electrode body 150 therein. Electrical connection to the positive electrode internal terminal 11 made of aluminum joined to the rectangular battery case 110, the positive electrode active material layer non-forming portion 151a (positive electrode end) of the electrode body 150, and the positive electrode internal terminal 11 In addition, the positive electrode external terminal 20 that is fastened to the battery case 110 and disposed outside the battery case 110 and the negative electrode active material layer non-forming portion 154a (negative electrode end portion) of the electrode body 150 are joined. The copper negative electrode internal terminal 61 is electrically connected to the negative electrode internal terminal 61, and is fastened to the battery case 110 so as to be external to the battery case 110. The negative electrode external terminal 70 is disposed, and the positive electrode external terminal 20 and the negative electrode external terminal 70 are arranged symmetrically with respect to a central position O (see FIG. 1) along the longitudinal direction of the battery case 110. . Further, the battery 100 includes the battery case 110 from the joining position of the positive electrode internal terminal 11 to the electrode body 150 (position of the welded portion 18) to the fastening position of the positive electrode external terminal 20 to the battery case 110 (position of the fastening portion 19). The battery case in which the distance x along the longitudinal direction is from the joining position of the negative electrode internal terminal 61 to the electrode body 150 (position of the welded portion 68) to the fastening position of the negative electrode external terminal 70 to the battery case 110 (position of the fastening portion 69). 110, the distance a along the longitudinal direction of the battery case 110 between the positive electrode active material layer non-forming portion 151a of the electrode body 150 and the battery case 110 is greater than the distance y along the longitudinal direction of the electrode body 150. It is smaller than the separation distance b along the longitudinal direction of the battery case 110 between the layer non-forming portion 154a and the battery case 110.

  In the electrode body 150 of this embodiment, the positive electrode plate 151 in which the positive electrode active material layer 153 is formed on the surface of the foil-like positive electrode base material 152 and the negative electrode active material layer 156 are formed on the surface of the foil-like negative electrode base material 155. The negative electrode plate 154 and the separator 157 that insulates the positive electrode plate 151 and the negative electrode plate 154 are wound. In addition, the electrode body 150 includes a positive electrode active material layer non-forming portion 151a that is wound in a state where a portion of the positive electrode plate 151 where the positive electrode active material layer 153 is not formed protrudes from the negative electrode plate 154. A negative electrode active material layer non-forming portion 154a that is wound on the negative electrode plate 154 in a state where a portion of the negative electrode plate 154 where the negative electrode active material layer 156 is not formed protrudes from the positive electrode plate 151 is provided in the winding axis direction. It is on the other end side.

  In the battery 100 of the present embodiment, the positive electrode external terminal 20 and the negative electrode external terminal 70 are arranged symmetrically with respect to the center position in the longitudinal direction of the battery case 110. The separation distance a between the positive electrode active material layer non-forming portion 151a of the electrode body 150 and the battery case 110 along the longitudinal direction of the battery case 110 is equal to the negative electrode active material layer non-forming portion 154a of the electrode body 150 and the battery case 110. The electrode body 150 is accommodated in the battery case 110 so as to be smaller than the separation distance b. When such an electrode body 150 is accommodated, the shapes of the positive electrode internal terminal 11 and the negative electrode internal terminal 61 are differentiated as follows. That is, in the longitudinal direction of the battery case 110, the joining position of the positive electrode internal terminal 11 with respect to the electrode body 150 (position of the welded portion 18) and the fastening position of the positive electrode external terminal 20 with respect to the battery case 110 (position of the fastening portion 19). The amount of displacement x when viewed is the battery between the joining position of the negative electrode internal terminal 61 with respect to the electrode body 150 (position of the weld portion 68) and the fastening position of the negative electrode external terminal 70 with respect to the battery case 110 (position of the fastening portion 69). The case 110 is configured to be larger than the amount of deviation y when viewed in the longitudinal direction. In other words, the distance from the center position O along the longitudinal direction of the battery case 110 to the welded portion 18 on the positive electrode side is longer than the distance from the center position O along the longitudinal direction of the battery case 110 to the welded portion 68 on the negative electrode side. It is comprised so that it may become. That is, as compared with the copper negative electrode internal terminal 61, the aluminum positive electrode internal terminal 11 extends from the fastening position of the external terminal to a position closer to the end of the battery case 110.

  Therefore, the amount of material (copper amount) required to form the negative electrode internal terminal 61 is smaller than the configuration of the negative electrode internal terminal 61 in the same shape as the positive electrode internal terminal 11. The copper constituting the negative electrode internal terminal 61 is a higher cost material than the aluminum constituting the positive electrode internal terminal 11. Therefore, according to the present embodiment, the material cost necessary to manufacture the negative electrode internal terminal 61 that is more expensive than the positive electrode internal terminal 11 can be reduced, and thus the battery 100 can be manufactured at a low cost. In addition, the size of the battery case 110 and the arrangement positions of the positive electrode external terminal 20 and the negative electrode external terminal 70 with respect to the battery case 110 do not need to be changed from the conventional products. That is, according to the present embodiment, even when it is possible to form an electrode body having the same capacity as the conventional one with a smaller size than the conventional one, the size of the battery case 110 and the batteries of the positive external terminal 20 and the negative external terminal 70 are the same. Since it is not necessary to change the arrangement position with respect to the case 110, it is possible to manufacture a battery at a lower cost than in the case where the design of these parts is changed.

  Even if the positive electrode internal terminal 11 is formed in a straight shape like the negative electrode internal terminal 61, the amount of the aluminum material can be reduced as compared with the curved shape shown in FIG. However, since copper is a more expensive material than aluminum, it is possible to reduce the size of the electrode body, and when either one of the positive electrode internal terminal 11 or the negative electrode internal terminal 61 is made straight. From the viewpoint of cost reduction, it is desirable that the negative electrode internal terminal 61 has a straight shape.

  In addition, the battery 100 of the present embodiment includes an insulating film 170 that is interposed between the electrode body 150 and the battery case 110 and insulates the electrode body 150 and the battery case 110, and does not form a positive electrode active material layer in the electrode body 150. The distance c from the positive electrode side end surface 150a (one end surface) on the part 151a (positive electrode end) side to the left inner surface 170a of the insulating film 170 facing the positive electrode side end surface 150a is the negative electrode active material layer non-formation in the electrode body 150 The distance d from the negative electrode side end surface 150b (the other end surface) on the side of the portion 154a (negative electrode end portion) to the right inner surface 170b of the insulating film 170 facing the negative electrode side end surface 150b is smaller.

  Therefore, the gap between the negative electrode active material layer non-forming portion 154a of the electrode body 150 and the insulating film 170 is larger than the gap between the positive electrode active material layer non-forming portion 151a of the electrode body 150 and the insulating film 170. Therefore, as compared with the case where the gap between the negative electrode active material layer non-forming portion 154a of the electrode body 150 and the insulating film 170 is configured to have the same size as the positive electrode side, the negative electrode internal terminal 61 and the negative electrode active material of the electrode body 150 It can suppress that the layer non-formation part 154a contact | connects the insulating film 170. FIG. Here, when the battery 100 is exposed to a high temperature or deteriorates over time, if the negative electrode internal terminal 61 or the negative electrode active material layer non-forming portion 154a of the electrode body 150 comes into contact with the insulating film 170, the insulating film 170 Copper ions may enter and cause insulation failure. In particular, when the insulating film 170 is an olefin resin as in the embodiment, a poor insulation can occur remarkably. However, in the present embodiment, as described above, the negative electrode internal terminal 61 and the negative electrode active material layer non-forming portion 154a of the electrode body 150 can be prevented from coming into contact with the insulating film 170. Infiltration can be suppressed. Therefore, the insulation by the insulating film 170 can be maintained.

  Further, in the battery 100 of the present embodiment, the insulating film 170 is provided in the left inner side of the battery case 110 facing the positive electrode side end surface 150a (one end surface) of the electrode body 150 on the positive electrode active material layer non-forming portion 151a (positive electrode end) side. Also from the surface 110a, the same distance from the right inner surface 110b of the battery case 110 facing the negative electrode side end surface 150b (other end surface) on the negative electrode active material layer non-forming portion 154a (negative electrode end portion) side of the electrode body 150, The distance b (see FIG. 1) from the negative electrode side end surface 150b of the electrode body 150 to the right inner surface 110b of the battery case 110 facing the negative electrode side end surface 150b is arranged in the battery case 110. It is larger than twice the distance from 110 to the insulating film 170.

  Therefore, even when the insulating film 170 moves so as to approach the negative electrode active material layer non-forming portion 154a of the electrode body 150, the insulating film 170 and the negative electrode active material layer non-forming portion 154a of the electrode body 150 are in contact with each other. There is no. Therefore, it is possible to prevent copper ions from entering the insulating film 170 from the negative electrode active material layer non-forming portion 154a of the electrode body 150.

  Further, in the battery 100 of the present embodiment, the electrolytic solution is injected into the battery case 110 at a position that is offset toward the positive electrode external terminal 20 side from the center position O (see FIG. 1) along the longitudinal direction. A liquid injection port 113n is provided.

  In the battery 100 having such a configuration, since the liquid injection port 113n is located closer to the positive electrode external terminal 20 side, the negative electrode active material layer non-forming portion 154a and the negative electrode internal terminal 61 of the electrode body 150 are Compared to the case where the liquid injection port 113n is provided at the center position O in the longitudinal direction of the battery case 110, the liquid injection port 113n is farther from the liquid injection port 113n, and the electrolyte does not easily permeate. However, in the present embodiment, the separation distance b between the negative electrode active material layer non-forming portion 154a of the electrode body 150 and the battery case 110 is equal to the separation distance a between the positive electrode active material layer non-forming portion 151a of the electrode body 150 and the battery case 110. Longer than. That is, the gap between the negative electrode active material layer non-forming portion 154a and the battery case 110 is wider than the positive electrode side. Therefore, the electrolyte injected into the battery case 110 tends to spread to the negative electrode active material layer non-forming part 154a side. Accordingly, the electrolytic solution can be sufficiently permeated also into the negative electrode active material layer non-forming part 154a side of the electrode body 150.

  Moreover, in the battery 100 of this embodiment, the insulators 36 and 86 are provided with the notch part 42 (refer FIG. 5). Therefore, when the caulking portion 14 of the positive electrode internal terminal 11 and the caulking portion 64 of the negative electrode internal terminal 61 are caulked, the stress generated by the moment received by the insulators 36 and 86 is dispersed. Therefore, the insulators 36 and 86 can be prevented from cracking.

  As mentioned above, although this invention was demonstrated according to embodiment, it cannot be overemphasized that this invention is not limited to the above-mentioned embodiment, It can change suitably and apply in the range which does not deviate from the summary. For example, in the above embodiment, a lithium secondary battery is exemplified as the battery, but the technical idea of the present invention can be applied to other types of batteries.

  Moreover, in the said embodiment, although the positive electrode internal terminal 11 and the positive electrode external terminal 20 were comprised with aluminum, you may comprise with the alloy (aluminum alloy) which has aluminum as a main component. Moreover, although the negative electrode internal terminal 61 and the negative electrode external terminal 70 were comprised with copper, you may comprise with the alloy (copper alloy) which has copper as a main component.

  Moreover, in the said embodiment, although the positive electrode internal terminal 11 and the positive electrode external terminal 20 were comprised separately, you may comprise integrally. Moreover, although the negative electrode internal terminal 61 and the negative electrode external terminal 70 are comprised separately, you may comprise integrally.

DESCRIPTION OF SYMBOLS 10 ... Positive electrode member 11 ... Positive electrode internal terminal 20 ... Positive electrode external terminal 60 ... Negative electrode terminal member 61 ... Negative electrode internal terminal 70 ... Negative electrode external terminal 100 ... Battery 110 ... Battery case 110a ... Left inner surface (inner surface) of battery case
110b ... Right inner surface (inner surface) of battery case
113n ... Liquid injection port 150 ... Electrode body 150a ... Positive electrode side end surface (one end surface)
150b ... Negative electrode side end surface (other end surface)
151: Positive electrode plate 151a: Positive electrode active material layer non-formation part (positive electrode end part)
154 ... Negative electrode plate 154a ... Negative electrode active material layer non-formation part (negative electrode end part)
157 ... Separator 170 ... Insulating film 170a ... Left inner surface (inner surface) of insulating film
170b ... Inner film right inner surface (inner surface)

Claims (3)

An electrode body formed by winding a positive electrode plate and a negative electrode plate with a separator interposed therebetween,
A flat rectangular battery case that accommodates the electrode body therein;
An aluminum positive electrode internal terminal joined to the positive electrode end of the electrode body;
A positive external terminal electrically connected to the positive internal terminal and fastened to the battery case and disposed outside the battery case;
A copper negative electrode internal terminal joined to the negative electrode end of the electrode body;
A negative electrode external terminal that is electrically connected to the negative electrode internal terminal and that is fastened to the battery case and disposed outside the battery case;
The positive electrode external terminal and the negative electrode external terminal are arranged symmetrically with respect to a central position along the longitudinal direction of the battery case,
The distance along the longitudinal direction of the battery case from the joining position of the positive electrode internal terminal to the electrode body to the fastening position of the positive electrode external terminal to the battery case is from the joining position of the negative electrode internal terminal to the electrode body, Greater than the distance along the longitudinal direction of the battery case to the fastening position of the negative external terminal with respect to the battery case;
The separation distance along the longitudinal direction of the battery case between the positive electrode end portion of the electrode body and the battery case is larger than the separation distance along the longitudinal direction of the battery case between the negative electrode end portion of the electrode body and the battery case. A battery characterized by being small. The battery according to claim 1,
An insulating film interposed between the electrode body and the battery case to insulate the electrode body and the battery case;
The distance from the one end face on the positive electrode end side in the electrode body to the inner surface of the insulating film facing the one end face is opposite to the other end face from the other end face on the negative electrode end side in the electrode body. A battery characterized by being smaller than the distance to the inner surface of the insulating film. A battery according to claim 1 or claim 2,
The battery case is provided with a liquid injection port for injecting an electrolytic solution into the battery case at a position offset toward the positive electrode external terminal side from a center position along a longitudinal direction thereof. Battery to play.

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