JP2011076787A - Secondary battery and method of manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce internal resistance and to facilitate assembly for a battery pack. <P>SOLUTION: In a lithium ion secondary battery, an electric power generation element group 6 is housed inside a flat rectangular solid vessel 10, and external terminals 4A and 4B respectively connected to positive and negative electrode current collection parts 6A and 6B of the electric power generation element group are fixed to the vessel. The positive and negative electrode external terminals are attached to a short band-shaped side wall 110B, and the positive and negative electrode current collection parts of the electric power generation element group are disposed close to the positive and negative electrode external terminals respectively. Since the positive and negative electrode current collection parts are placed across the overall width along the short band-shaped side wall 110B, positive and negative electrode connection members 5A and 5B can be formed to have wide width. Since the positive and negative electrode current collection parts and the positive and negative electrode external terminals are close to each other, the positive and negative electrode connection members can be shortened. Therefore, electric resistance of the positive and negative electrode connection members and the internal resistance of the secondary battery can be reduced, and battery characteristics such as charging and discharging performance can be improved. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a secondary battery in which a power generation element group is housed in a shallow battery can and the opening of the battery can is sealed with a battery lid, and a method for manufacturing the same.

  In response to social trends in local environmental protection, there is an urgent need to commercialize and popularize secondary batteries for driving vehicles such as hybrid cars and electric cars. The structure of the secondary battery for driving a vehicle is that a sheet for both positive and negative electrodes (positive and negative electrode plates), a separator for insulation between the positive and negative electrode plates, and an electrolytic solution are sealed with metal or resin. It is well known to provide an external terminal that is housed in a container and joined to both electrodes of the power generation element.

  Most of the secondary batteries that have been put to practical use so far have a cylindrical shape. However, in the case of a secondary battery for driving a vehicle, it is several dozens to increase the output and capacity. More than a hundred secondary batteries need to be assembled into a battery pack and mounted on a single vehicle. From the viewpoint of improving mounting density, square-shaped secondary batteries are actively put into practical use. It has become.

  A conventionally known prismatic secondary battery has a metal deep bottom battery can formed by a deep drawing method, and the cross section of the battery can is formed in a flat rectangular shape. Here, the bipolar direction of the power generation element is referred to as the WH direction, the extension direction of the power generation element group both poles is referred to as the HH direction, and the power generation element group thickness direction is referred to as the DH direction. In the prismatic secondary battery, the HH direction, WH direction, and DH direction correspond to the depth direction of the battery can, the long side direction of the flat cross section, and the short side direction of the flat cross section, respectively.

  A power generation element group is accommodated in the battery can via an insulating case. In the power generation element group, positive and negative electrode plates each having a current collector are wound or stacked, and uncoated portions of the positive and negative electrode active material mixture are respectively formed at both ends arranged in the WH direction. A connection plate (connection member) is bonded to the uncoated portion at the bonded portion by an ultrasonic bonding method or the like. The opening of the battery can is sealed by welding a metal battery lid with a laser beam welding method, etc. The battery lid has positive and negative electrodes for connection to the outside to avoid electrical contact with the battery lid. And it fixes through the sealing member for keeping airtight inside a battery. The battery lid is provided with a liquid injection port, and an electrolytic solution is injected into the battery can from the liquid injection port. The inlet is hermetically sealed by laser beam welding.

  In such a secondary battery, the connection plate extends to the battery lid along the WH direction end of the power generation element group, that is, the short side of the battery can, and is connected to the positive and negative electrode parts. For this reason, the shape of the connection plate is limited by the shape of the power generation element group and the battery can, and the current path width becomes narrow, and the battery internal resistance may increase.

  Therefore, in the secondary battery of Patent Document 1, four flat side surfaces, a wide bottom surface defined by these four side surfaces and an opening facing the bottom surface are provided, and the opening is sealed with a battery lid. is doing. And the positive / negative electrode part is provided in the battery cover, the connecting plate (connecting member) is extended in the DH direction, the distance is shortened, and the internal resistance is reduced.

Japanese Patent No. 3997369

  In a vehicular secondary battery system, when a large number of secondary batteries are connected, the secondary batteries are generally densely arranged in the DH direction. In the secondary battery of Patent Document 1, the positive and negative terminals are hidden between adjacent secondary batteries. Therefore, connection work is not easy. Therefore, the secondary battery of Patent Document 1 is difficult to be assembled.

In order to avoid such a problem, if the positive and negative terminals are provided in the WH direction or the HH direction, the beam will pass in the vicinity of the positive and negative terminals when the battery cover is welded to the battery can. The welding operation is virtually impossible. Although it is conceivable to irradiate the beam from the bottom surface, the bottom surface is highly likely to interfere with the beam source.
That is, the secondary battery of Patent Document 1 is difficult to be assembled.

(1) A secondary battery according to the invention of claim 1 includes a flat bottomed battery can having an opening at the top and a side wall at the side, and a battery lid for sealing the opening. A container, a power generation element group having a positive electrode, a negative electrode, a positive electrode current collector, and a negative electrode current collector housed in the battery container; and mounted on the side wall of the battery can; A positive electrode external terminal and a negative electrode external terminal on which a current collector connection surface to which the current collector and the negative electrode current collector are connected is formed; a positive electrode connection member that connects the positive electrode current collector and the positive electrode external terminal; and A negative electrode connection member that connects a negative electrode current collector and a negative electrode external terminal, the positive electrode external terminal and the positive electrode connection member, and the negative electrode external terminal and the negative electrode connection member from the outside of each external terminal or the opening It is fixed by welding from the part side And butterflies.
(2) A secondary battery according to a second aspect of the present invention is the secondary battery according to the first aspect, wherein the side wall has a rectangular frame shape in which a pair of long belt-shaped side walls and a pair of short belt-shaped side walls are continuously formed, and the external terminals Are fixed to the pair of short belt-like side walls, respectively, and each connection member extends along the current collector connection surface while continuing to the base and the base extending in parallel with the bottom wall of the battery can. A contact end portion formed on the contact member, and a contact surface between the connection member and the contact end portion is fixed by welding.
(3) The invention of claim 3 is the secondary battery according to any one of claims 1 to 3, further comprising a horizontal direction positioning means for positioning the power generation element group in the direction of the positive and negative electrode current collector. It is characterized by that.
(4) The invention of claim 4 is the secondary battery according to claim 3, wherein the horizontal positioning means is provided on the connection member and the external terminal, and the connection member and the external terminal are connected to each other. Contact surfaces that abut in the direction of the positive and negative current collectors are formed, respectively, and the power generation element group is positioned in the direction of the positive and negative current collectors.
(5) The invention of claim 5 is the secondary battery according to any one of claims 1 to 3, further comprising a depth direction positioning means for positioning the power generation element group in the depth direction of the battery can. It is characterized by.
(6) In the secondary battery according to claim 5, the battery can depth direction positioning means is provided in the connection member and the external terminal, and the connection member and the external terminal include Contact surfaces that contact each other in the battery depth direction are formed, and the power generation element group is positioned in the battery depth direction.
(7) The invention of claim 7 includes a battery can having a flat side wall, a bottom wall defined by the side wall and wider than the side wall, and an opening facing the bottom wall, and the opening. A battery lid attached to the battery can, a power generation element group accommodated in the battery can and provided with a positive electrode and a negative electrode part, and the power generation element group accommodated in the battery can The positive electrode current collector and the negative electrode current collector in the vicinity of each of the side walls penetrating the side wall and being sealed and fixed to the side wall and supported inside the battery can A method of manufacturing a secondary battery comprising a positive electrode and a negative electrode external terminal, wherein the external terminal is attached and fixed to the side wall of the battery can via a sealing material, and the power generation Connected to each of the positive current collector and negative current collector of the element group A step of positioning the power generating element group in the battery can by supporting the connection member by the support portion of the external terminal, and a contact surface between the external terminal and the connection member. And a step of welding from the opening or from the outside of the external terminal, and a step of attaching the battery lid to the opening.

  According to the present invention, it is possible to provide a secondary battery and a manufacturing method that have a low internal resistance and can be easily assembled.

1 is a partial longitudinal sectional view showing a first embodiment of a secondary battery according to the present invention. The disassembled perspective view which shows the structure of the electric power generation element group of the secondary battery of FIG. The perspective view which shows the other structure of the electric power generation element group of the secondary battery of FIG. The partially broken perspective view which shows the battery can and battery cover of the secondary battery of FIG. The fragmentary longitudinal cross-sectional view which follows the VV arrow line of FIG. The fragmentary longitudinal cross-section which shows 2nd Embodiment of the secondary battery by this invention. The fragmentary longitudinal cross-section which shows 2nd Embodiment of the secondary battery by this invention. The fragmentary longitudinal cross-section which shows 3rd Embodiment of the secondary battery by this invention. FIG. 8 is a partial vertical cross-sectional view illustrating a manufacturing process of the secondary battery in FIG. 7. FIG. 8 is a partial vertical cross-sectional view illustrating a manufacturing process of the secondary battery in FIG. 7. FIG. 8 is a partial vertical cross-sectional view illustrating a manufacturing process of the secondary battery in FIG. 7. FIG. 8 is a partial vertical cross-sectional view illustrating a manufacturing process of the secondary battery in FIG. 7. FIG. 8 is a partial vertical cross-sectional view illustrating a manufacturing process of the secondary battery in FIG. 7. FIG. 8 is a partial vertical cross-sectional view illustrating a manufacturing process of the secondary battery in FIG. 7. FIG. 8 is a partial vertical cross-sectional view illustrating a manufacturing process of the secondary battery in FIG. 7. The fragmentary longitudinal cross-section which shows 4th Embodiment of the secondary battery by this invention. The other partial longitudinal cross-sectional view which shows 4th Embodiment of the secondary battery by this invention. The fragmentary longitudinal cross-section which shows 5th Embodiment of the secondary battery by this invention. The fragmentary longitudinal cross-section which shows 6th Embodiment of the secondary battery by this invention.

Hereinafter, embodiments of a secondary battery according to the present invention will be described in detail with reference to the accompanying drawings.
[First Embodiment]

  As shown in FIGS. 1 and 4, the lithium ion secondary battery 30 includes a flat rectangular parallelepiped container 10 and a power generation element group 6 accommodated in the container 10. The power generation element group 6 is immersed in an electrolytic solution (not shown) and insulated from the container 10 by a flexible insulating case 7 (FIG. 4). The power generation element group 6 includes a positive electrode current collector 6A and a negative electrode current collector 6B. The positive electrode current collector 6A and the negative electrode current collector 6B are connected to the container 10 via the positive electrode connection member 5A and the negative electrode connection member 5B, respectively. Are connected to a positive external terminal 4A and a negative external terminal 4B. The positive and negative external terminals 4A and 4B are exposed to the outside and can be connected to each other or to other electrical devices.

  In addition, in order to simplify illustration and description, the insulating case 7 is omitted in drawings other than FIG.

  Hereinafter, in order to simplify the description, the three-dimensional three directions in the secondary battery 30 are defined as follows. That is, the direction connecting the positive electrode external terminal 4A and the negative electrode external terminal 4B of the container 10 (left-right direction in FIG. 1) is the WH direction (positive and negative electrode part direction), the thickness direction of the container 10, that is, the bottom wall 111 of the battery can 11 The direction connecting the battery lid 12 (the vertical direction in FIG. 1) is the DH direction (battery can depth direction), and the WH direction and the direction orthogonal to the DH direction are HH directions. That is, the container 10 is thin in the DH direction (side surface height direction), and the bottom wall 111 is long in the WH direction and short in the HH direction.

  As shown in FIG. 2, the power generation element group 6 is formed by winding a belt-like positive electrode plate 6P1 and a negative electrode plate 6P2 via two belt-like separators 6C, and the HH direction is larger than the DH direction. It is formed in a long flat coil shape.

  The positive electrode plate 6P1 is applied, for example, to a positive electrode current collector foil made of aluminum with a positive electrode active material mixture containing a positive electrode active material such as lithium manganate or a lithium-containing transition metal composite oxide substantially evenly and substantially uniformly. It is formed by wearing. In addition to the positive electrode active material, the positive electrode active material mixture is blended with a conductive agent such as a carbon material and a binder (binder) such as polyvinylidene fluoride (hereinafter abbreviated as PVDF). When the material mixture is applied, the viscosity of the positive electrode active material mixture is adjusted with a dispersion solvent such as N-methylpyrrolidone (hereinafter abbreviated as NMP). When the positive electrode active material mixture is applied, an uncoated portion 6RA is formed on the side edge on one side in the width direction of the positive electrode current collector foil. That is, aluminum is exposed in the uncoated portion 6RA. Then, it is dried and the density is adjusted with a roll press.

  For example, the negative electrode plate 6P2 is formed by coating a negative electrode active material mixture containing a carbon material such as graphite capable of reversibly occluding and releasing lithium ions on both surfaces of a copper negative electrode current collector foil. Formed. In addition to the negative electrode active material, the negative electrode active material mixture contains a conductive material such as acetylene black and a binder such as PVDF. When the negative electrode active material mixture is applied to the copper foil, the viscosity of the negative electrode active material mixture is adjusted with a dispersion solvent such as NMP. When the negative electrode active material mixture is applied, an uncoated portion 6RB where the negative electrode active material mixture is not applied is formed on the side edge on one side in the longitudinal direction of the copper foil. That is, the copper foil is exposed in the uncoated portion 6RB. Then, it is dried and the density is adjusted with a roll press.

  The length of the negative electrode plate 6P2 is such that when the positive electrode plate 6P1 and the negative electrode plate 6P2 are wound, the positive electrode plate 6P1 does not protrude from the negative electrode plate 6P2 in the winding direction at the innermost winding and outermost winding. And longer than the length of the positive electrode plate 6P1. In addition, the width (length in the WH direction) of the coating portion of the negative electrode active material mixture is such that the coating portion of the positive electrode active material mixture is in the negative electrode active portion direction (WH direction) of the power generation element group 6. The width is set to be longer than the width of the coated portion of the positive electrode active material mixture so as not to protrude from the coated portion of the material mixture.

  The uncoated portions 6RA and 6RB where the active material mixture at the end portions in the width direction of the positive electrode plate 6P1 and the negative electrode plate 6P2 is not applied are pressed into a flat shape in the DH direction after winding, An electric part 6A and a negative electrode current collector 6B are formed.

  Since the power generation element group 6 is thicker by the amount of the active material mixture in the other portions (coated portion 6C) compared to the uncoated portions 6RA and 6RB, the positive current collecting portion 6A and the negative current collecting portion In the part 6B, an inclination in which the thickness increases toward the central part in the WH direction is generated.

  The battery can 11 is formed, for example, by processing a thin aluminum plate by a shallow drawing method into a flat shape with a bottom, and an opening 113 is provided at the top. The battery can 11 has a rectangular frame-shaped side wall 110 and a bottom wall 111, and the upper opening 113 is sealed by welding the battery lid 12 by laser beam welding or the like (the welded portion is indicated by W2). .

  The side wall 110 of the battery can 11 is formed by four surfaces, ie, a pair of opposed long belt-like side walls 110A and a pair of opposed short belt-like side walls 110B. A laterally long terminal mounting opening 115 is provided at substantially the center of the short belt-shaped side wall 110B, the positive electrode external terminal 4A is provided in the terminal mounting opening 115 of one short belt-shaped side wall 110B, and the other short belt-shaped side wall 110B. The negative electrode external terminal 4B is attached to the terminal attachment opening 115.

  The sealing material 13 is formed by transfer molding around the periphery of the positive external terminal 4A and the negative external terminal 4B, and the positive external terminal 4A and the negative external terminal 4B are attached to the terminal mounting opening 115 via the sealing material 13. The terminal mounting opening 115 is sealed. The sealing material 13 insulates the positive electrode external terminal 4A and the negative electrode external terminal 4B from the battery can 11 and fixes the positive electrode external terminal 4A and the negative electrode external terminal 4B to the battery can 11.

  In the battery can 11, the power generation element group 6 described above is disposed in a direction in which the positive electrode current collector 6 </ b> A and the negative electrode current collector 6 </ b> B face the positive electrode external terminal 4 </ b> A and the negative electrode external terminal 4 </ b> B, respectively. The connecting member 5B connects the positive current collector 6A and the negative current collector 6B to the positive external terminal 4A and the negative external terminal 4B, respectively.

  As shown in FIGS. 1 and 4, the positive external terminal 4A attached to the terminal attachment opening 115 of the short belt-like side wall 110B is made of a metal member having a predetermined thickness that is thicker than the thickness of the battery can 11, and is entirely The cross-sectional shape is a substantially hat shape. The positive electrode external terminal 4A has a through hole 20 that communicates the inside of the battery can 11 with the outside, and a counterbore 41 is provided around the through hole 20 as shown in FIG. The counterbore 41 has a size and depth to accommodate the collar portion of the plug member of the through hole.

  The negative external terminal 4B is also formed in the same manner as the positive external terminal 4A. That is, the negative electrode external terminal 4B is made of a metal member having a predetermined thickness that is thicker than the thickness of the battery can 11, and the cross-sectional shape as a whole is a substantially hat shape. The negative electrode external terminal 4B has a through hole 20 that communicates the inside of the battery can 11 with the outside, and a counterbore 41 is provided around the through hole 20 as shown in FIG. The counterbore 41 has a size and depth to accommodate the collar portion of the plug member of the through hole.

  The container inner surface of the support portion 4AS protruding inside the container 10 of the positive electrode external terminal 4A is a positive electrode current collector contact surface 4AT, and the container inner surface of the support portion 4BS protruding inside the container 10 of the negative electrode external terminal 4B is the negative electrode current collector portion. The contact surface is 4BT.

  In each of the positive electrode current collector 6A and the negative electrode current collector 6B, the positive electrode connecting member 5A and the negative electrode connecting member 5B are electrically and mechanically bonded in advance by ultrasonic bonding to produce a current collector assembly. The substantially L-shaped positive electrode connecting member 5A extends in parallel with the bottom wall 111, and has a horizontal base portion 5AA formed to have substantially the same width as the width of the external terminal, and the support portion 4AS while continuing to the horizontal base portion 5AA. A vertical contact end 5AS bent in the direction of the container opening 113 (a direction orthogonal to the bottom wall 111) is provided. The negative electrode connecting member 5B also includes a horizontal base portion 5BA similar to the positive electrode connecting member 5A and a vertical contact end portion 5BS.

  A positive electrode current collector 6A is fixed to the horizontal base 5AA of the positive electrode connection member 5A, and a contact surface 5AT of the vertical contact end 5AS is brought into contact with a current collector contact surface 4AT of the positive electrode external terminal 4A and is laser beam welded. (The weld is indicated by W1). Laser beam welding of the positive electrode connection member 5A and the positive electrode external terminal 4A is performed from the outside of the positive electrode external terminal 4A to the mutual contact surfaces 5AT and 4AT.

  The negative electrode current collector 6B is fixed to the horizontal base 5BA of the negative electrode connection member 5B, and the contact surface 5BT of the vertical contact end 5BS is brought into contact with the current collector contact surface 4BT of the negative electrode external terminal 4B and is laser beam welded. . Laser beam welding of the negative electrode connection member 5B and the negative electrode external terminal 4B is performed from the outside of the negative electrode external terminal 4B to the mutual contact surfaces 5BT and 4BT.

  Here, the contact surface 5AT of the vertical contact end 5AS of the positive electrode connection member 5A is on the contact surface 4AT of the positive electrode external terminal 4A, and the contact surface of the vertical contact end 5BS of the negative electrode connection member 5B is on the contact surface 4BT of the negative electrode external terminal 4B. When the 5BT comes into surface contact with each other, the power generating element group 6 is positioned in the positive and negative current collector direction (WH direction).

  As shown in FIG. 5, one or both of the positive electrode external terminal 4 </ b> A and the negative electrode external terminal 4 </ b> B (in this embodiment, the positive electrode external terminal 4 </ b> A) is provided with a through hole 20 that communicates the inside and outside of the battery can 11. 41 is drilled in the bottom wall. The through hole 20 serves as a liquid injection port for injecting the electrolytic solution into the container 10. The liquid injection stopper 22 is provided with a collar portion 26. The collar portion 26 is fixed by laser beam welding after being fitted into the counterbore 41.

  The electrolytic solution is injected from a liquid injection port (through hole) 20 provided in the positive electrode external terminal 4A. After injecting the electrolyte, a stopper member (injection stopper) 22 is inserted into the injection hole 20 to seal the inside of the container.

  As shown in FIG. 5, the vertical contact end 5AS of the positive electrode connecting member 5A is formed with a notch 5AR at a position corresponding to the liquid injection port 20, so that there is no hindrance to the injection of the electrolytic solution.

  When assembling the assembled battery, the positive external terminals 4A and the negative external terminals 4B are connected by a bus bar (not shown) or the like. The bus bar used for connecting the positive external terminals 4A is made of, for example, aluminum. In addition, for example, an aluminum / copper composite material (clad material) is used for the bus bar used for the mutual connection of the negative electrode external terminals 4B. A composite material in which aluminum and copper are electrically and mechanically joined by ultrasonic joining or caulking may be used.

  In general, the material of the battery can 11 is, for example, aluminum, the material of the positive electrode external terminal 4A is, for example, aluminum, the material of the negative electrode external terminal 4B is, for example, copper, the material of the battery lid 12 is, for example, aluminum, and the material of the sealing material 13 is, for example, polyphenylene sulfide. (Hereinafter abbreviated as PPS) and polybutylene terephthalate (hereinafter abbreviated as PBT). The unevenness in the thickness direction of the battery lid 12 is set to be smaller than the unevenness amount of the battery can 11.

  According to the battery of the first embodiment described above, the following operational effects can be obtained.

(1) The positive electrode external terminal 4A and the negative electrode external terminal 4B which are thicker than the plate thickness of the battery can material and the plate thickness of the battery lid material are provided in the terminal attachment opening 115 provided in the short belt-like side wall 110B of the battery can 11. . Further, a container internal / external communication through hole 20 that penetrates the inside and outside of the battery container was provided in the positive electrode external terminal 4A, and the container internal / external communication through hole 20 was sealed with a plug 22. Therefore, when an opening is provided in a battery can or a battery lid as in the conventional example, a certain plate thickness is required to ensure the mounting strength and reliability of the plug, which has hindered weight reduction of the battery. However, according to the present invention, the thick positive electrode external terminal 4A is provided on the short belt-like side wall 110B, and the container internal / external communication through hole 20 is provided in the external terminal 4A. The plate thickness can be made thinner than the conventional example, which contributes to the weight reduction of the battery.
Thereby, for example, even if an iron plate having a relatively large specific gravity is adopted as the material of the battery can 11 and the battery lid 12, the container 10 can be reduced in weight. When an iron plate is used, the welded portion W2 between the battery container 11 and the battery lid 12 can be formed firmly.

(2) A counterbore 41 is provided around the inner and outer communication through holes 20 in the external terminal 4A. Therefore, since the flange portion 26 of the stopper that seals the inside / outside communication through-hole 20 is accommodated in the counterbore 41, the weld bead does not rise on the surface of the battery case. Further, as described in (1), it contributes to weight reduction. When a through hole for connecting the inside and outside of a container is provided in a battery can or a battery lid as in the prior art, the plate thickness is increased in order to provide a counterbore, which hinders weight reduction of the battery.

(3) Since the positive electrode current collector 6A and the negative electrode current collector 6B are arranged along the longitudinal direction of the short belt-like side wall 110B, the positive electrode connection member 5A and the negative electrode connection member 5B can be formed wide. Moreover, since the positive electrode current collector 6A and the positive electrode external terminal 4A and the negative electrode current collector 6B and the negative electrode external terminal 4B are close to each other, the positive electrode connecting member 5A and the negative electrode connecting member 5B can be shortened.
Therefore, the electrical resistance of the positive electrode connecting member 5A and the negative electrode connecting member 5B, and thus the internal resistance of the secondary battery can be reduced, and battery performance such as charge / discharge performance can be improved.

(4) The positive electrode current collector 6A, the negative electrode current collector 6B, the positive electrode external terminal 4A, and the negative electrode external terminal 4B are arranged close to each other, thereby being influenced by the size of the power generation element group 6, the shape of the container 10, and the like. Current paths can be optimized.

(5) Since the positive electrode connecting member 5A, the negative electrode connecting member 5B, the positive electrode external terminal 4A, and the negative electrode external terminal 4B extend in the longitudinal direction of the short belt-shaped side wall 110B and can be set to a relatively large size, the mutual contact surface 5AT 5BT can also be set sufficiently large, the welded portion W1 can be made a sufficient size, and the welding strength can be ensured.

(6) The positive electrode current collector 6A and the negative electrode current collector 6B were brought close to the container side wall 110B and connected to the positive electrode external terminal 4A and the negative electrode external terminal 4B by the positive electrode connecting member 5A and the negative electrode connecting member 5B. Therefore, it is not necessary to route the positive electrode connecting member 5A and the negative electrode connecting member 5B in the WH direction or the HH direction in the container 10 as in the conventional case, the container dimensions in the WH direction and the HH direction can be reduced, and the battery size can be reduced. Can do.

(7) The vertical wall 5AS of the positive electrode connection member 5A is in contact with and welded to the contact surface 4AT of the support portion 4AS of the positive electrode external terminal 4A, and the vertical wall 5BS of the negative electrode connection member 5B is connected to the support portion 4BS of the negative electrode external terminal 4B. The contact surface 4BT was contacted and welded. The power generation element group 6 before welding can be positioned in the WH direction to facilitate welding work.

(8) Since the positive electrode external terminal 4A and the negative electrode external terminal 4B are exposed on the side wall 110B of the container 10, when the secondary battery 30 is stacked in the DH direction, the positive electrode external terminal 4A and the negative electrode external terminal 4B are orthogonal to the stacking direction (DH direction). The positive external terminal 4A and the negative external terminal 4B are arranged adjacently in series. For this reason, the positive electrode external terminals 4A and the negative electrode external terminals 4B of the plurality of secondary batteries can be easily connected without causing interference with the laser beam. Thereby, the assembly cost of the assembled battery can be reduced.

(9) The vertical contact end 5AS of the positive electrode connection member 5A has a notch 5AR at a position corresponding to the liquid injection port 20, and the vertical contact end after the positive electrode connection member 5A is welded to the positive electrode external terminal 4A. The portion 5AS is prevented from becoming an obstacle to the injection of the electrolyte from the liquid injection port 20.

(10) When sealing the battery can 11 with the battery lid 12, there is no need to consider interference with the positive external terminal 4A and the negative external terminal 4B, so the battery can 11 and the battery cover 12 are laser beam welded. be able to. Thereby, the material of the aluminum main material can be adopted for the battery can 11 and the battery lid 12, and the entire secondary battery 30 can be reduced in weight.

(11) The positive and negative external terminals 4A and 4B are exposed to the outside of the battery can 11, and the outer surfaces of the contact surfaces 5AT and 5BT in the positive and negative external terminals 4A and 4B (the surfaces on the back of the contact surfaces 5AT and 5BT) are Since it is exposed to the outside of the battery can 11 with a sufficient size, the welding operation is easy.

(12) The sealing performance can be enhanced by sealing the liquid injection port 20 while firmly fixing the liquid injection plug 22 to the liquid injection port 20.

(13) The battery can 11 has a flat rectangular parallelepiped shape having the opening 113, and when viewed from the opening 113, the dimension (opening size) in the WH direction and the HH direction is large, and the dimension (depth) in the DH direction is small. . For this reason, it is easy to insert the power generation element group 6 into the battery can 11, and the possibility of damaging the power generation element group 6 at the edge of the opening 113 at the time of insertion is low. Therefore, the number of steps for assembling the secondary battery can be reduced and the yield can be improved.

(14) Since the battery can 11 does not require a conventional deep drawing process, its manufacturing cost is low.

  The power generation element group 6 is not limited to the configuration shown in FIG. 2, and can be formed by stacking positive and negative electrode plates 6P1 and 6P2 as shown in FIG.

The stacked power generation element group 6 is configured by alternately stacking rectangular positive electrode plates 6P1 and rectangular negative electrode plates 6P2 via rectangular separators 6C. At this time, the front and back of the positive electrode plate 6P1 and the negative electrode plate 6P2 are set so that the uncoated portions 6RA and 6RB are positioned on the opposite surfaces (reverse to each other).
The laminated power generation element group 6 configured as described above can achieve the same effects as when the power generation element group 6 of FIG. 2 is used.

[Second Embodiment]
Next, based on FIG. 6, FIG. 7, 2nd Embodiment of the secondary battery by this invention is described. In the figure, the same or corresponding parts as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted.

  In the second embodiment, the shapes of the vertical contact end portions 5AS and 5BS of the positive electrode connection member 5A and the negative electrode external terminal 5B are changed. 6 and 7 typically show only the positive electrode connection member 5A on the positive electrode terminal (external terminal) 4A side.

  The positive electrode connecting member 5A includes a horizontal base portion 5AA extending in parallel with the bottom wall 111, and a vertical contact end portion 5AS that is continuous with the base portion 5AA and bent along the support portion 4AS. The vertical contact end portion 5AS is bent along the contact surface 4AT while facing the support portion 5AS1 facing the support portion 4AS and the side surface 4ASS on the opening 113 side of the support portion 4AS. And it has load supporting part 5AS2 which supports power generation element group 6 in the state before welding. The contact surface 5AT is formed in the facing portion 5AS1, and the contact surface 5AT is laser beam welded to the contact surface 4AT. Laser beam welding is performed from the direction of the opening 113.

  The positive electrode connecting member 5A not only positions the power generating element group 6 in a state before welding in the WH direction by the facing portion 5AS1 in the vertical contact end portion 5AS, but also in the depth direction of the battery can 11 in the load support portion 5AS2 ( DH direction). The contact surfaces 4AT and 4BT and the facing portions 5AS1 and 5BS1 have a function of positioning the direction of the positive and negative current collecting portions of the power generation element group 6, and the side surfaces 4ASS and 4BSS and the load support portions 5AS2 and 5BS2 are the power generation element group 6 The battery can has a function of positioning in the depth direction.

  As shown in FIG. 7, as in the first embodiment, the positive electrode external terminal 4A is provided with a liquid injection port 20 having a counterbore 41, and the liquid injection port 20 is welded and sealed by a liquid injection plug 22. ing. Further, a notch 5AR is formed in the vertical contact end portion 5AS of the positive electrode connecting member 5A at a position corresponding to the liquid injection port 20 to prevent an obstacle to electrolyte injection.

  In the second embodiment, in addition to the effects of the first embodiment, it is possible to perform a welding operation after more reliably setting the position of the power generation element group portion 6, thereby improving work efficiency and positioning accuracy. it can.

[Third Embodiment]
Next, a third embodiment of the secondary battery according to the present invention will be described with reference to FIG. In the figure, the same or corresponding parts as those in the second embodiment are denoted by the same reference numerals and description thereof is omitted.

  The third embodiment employs the same positive electrode connecting member 5A and negative electrode external terminal 5B as those of the second embodiment, while the contact surfaces 5AT and 5BT to be laser welded are formed on the load support portions 5AS2 and 5BS2. It is a thing. FIG. 8 representatively shows only the positive electrode connecting member 5A on the positive electrode external terminal 4A side.

  The positive electrode connecting member 5A includes a base portion 5AA extending in parallel to the bottom wall 111, and a vertical contact end portion 5AS that is continuous with the base portion 5AA and bent along the support portion 4AS. The opposite part 5AS1 and load support part 5AS2 similar to the form are provided.

  The positive electrode connecting member 5A not only positions the power generating element group 6 in a state before welding in the WH direction by the facing portion 5AS1 in the vertical contact end portion 5AS, but also in the depth direction of the battery can 11 in the load support portion 5AS2 ( DH direction).

  The contact surfaces 4AT and 4BT and the facing portions 5AS1 and 5BS1 have a function of positioning the direction of the positive and negative current collecting portions of the power generation element group 6, and the side surfaces 4ASS and 4BSS and the load support portions 5AS2 and 5BS2 are the power generation element group 6 The battery can has a function of positioning in the depth direction.

On the other hand, unlike the second embodiment, the contact surface 5AT is formed on the load support portion 5AS2, and the contact surface 4AT1 is formed on the periphery of the support portion 4AS, and is welded to the contact surfaces 4AT1 and 5AT.
As in the second embodiment, laser beam welding is performed from the direction of the opening 113.

  As in the first and second embodiments, the position of the welded portion W2 can be changed, and is determined in consideration of the manufacturing efficiency, the battery environment resistance (temperature change) reliability, the influence on the internal resistance of the battery, and the like. Is done.

  As in the first and second embodiments, the positive electrode external terminal 4A is provided with a liquid injection port 20 and a liquid injection plug 22 (see FIG. 16), and the liquid injection port 20 is sealed by the liquid injection plug 22. .

[Production method]
Next, a method for manufacturing a secondary battery according to the third embodiment will be described with reference to FIGS.
The manufacturing process of the lithium ion secondary battery 30 includes a preparation process, a fixing process, a connection process, and a joining process.
In the preparation step, the positive and negative electrode plates 6P1 and 6P2 are wound to form the power generation element group 6, and then the positive electrode connection member 5A and the negative electrode connection member 5B are connected to the uncoated portions 6RA and 6RB, respectively.
In the fixing step, the positive and negative external terminals 4A and 4B are fixed to the terminal mounting openings 115 on the side wall 110B of the battery can 11 through the sealing member 13, respectively.
In the connecting step, the power generation element group 6 is inserted and installed in the battery can 11, and the positive and negative external terminals 4A and 4B are electrically and mechanically connected to the positive electrode connecting member 5A and the negative electrode connecting member 5B, respectively.
In the joining step, the battery can 11 is sealed with the battery lid 12.

The preparation process will be described in more detail. First, a positive electrode plate 6P1 and 6P2 prepared in advance are wound through a separator 6C. At this time, the separator 6C, the negative electrode plate 6P2, the separator 6C, and the positive electrode plate 6P1 are arranged in this order so that the uncoated part 6RA of the positive electrode plate 6P1 and the uncoated part 6RB of the negative electrode plate 6P2 are arranged on the opposite sides. They are laminated and wound so as to have a substantially rectangular cross section from one end in the longitudinal direction.
Only the separator 6C is wound around the winding start portion and the winding end portion about 2 to 3 times.
Further, the uncoated portions 6RA and 6RB are pressed to form the positive electrode current collector 6A and the negative electrode current collector 6B.

  A positive electrode connection member 5A and a negative electrode connection member 5B are arranged in the positive electrode current collector 6A and the negative electrode current collector 6B of the power generation element group 6 formed in this way, respectively, and as shown in FIG. The negative electrode connection member 5B (not shown) is subjected to ultrasonic treatment, and the positive electrode connection member 5A and the positive electrode current collector 6A, and the negative electrode connection member 5B and the negative electrode current collector 6B are joined together.

The fixing process will be described in more detail. The positive electrode external terminal 4A and the negative electrode external terminal 4B are fixed to the terminal mounting opening 115 of the battery can 11 through the seal member 13, respectively.
As shown in FIG. 9, the positive electrode external terminal 4A and the negative electrode external terminal 4B (not shown) are inserted into the terminal mounting opening 115 of the battery can 11, and as shown in FIG. Then, the positive electrode external terminal 4A and the negative electrode external terminal 4B (not shown) are held at a constant interval, and the sealing member 13 is formed by transfer molding a resin material such as PPS or PBT in the gap.
By the transfer mold, the relative positions of the battery can 11 and the positive external terminal 4A and the negative external terminal 4B are fixed, insulation between them is ensured, and airtightness is established.

  The connection process will be described in further detail. The power generation element group 6 to which the positive electrode connection member 5A and the negative electrode connection member 5B are obtained in the preparation process, and the positive and negative electrode exterior integrated in the battery can 11 obtained in the fixing process. The terminals 4A and 4B are electrically and mechanically connected.

As shown in FIGS. 12 and 13, the power generation element group 6 created in the preparation process is placed in the battery can 11 together with the positive electrode connection member 5 </ b> A and the negative electrode connection member 5 </ b> B via the insulating case 7 (not shown). The element group 6 and the positive electrode connecting member 5A and the negative electrode connecting member 5B are inserted and installed.
The positive electrode connecting member 5A, the negative electrode connecting member 5B, and the positive and negative electrode external terminals 4A and 4B are electrically and mechanically connected by laser beam welding from the direction of the opening 113 of the battery can 11, respectively.
As described above, since the positive electrode connecting member 5A and the negative electrode connecting member 5B can be formed wide, the internal resistance can be reduced.

In the first embodiment, only the welding positions and welding directions of the positive electrode connecting member 5A, the negative electrode connecting member 5B, and the positive and negative electrode external terminals 4A, 4B are different, and the other processes are the same.
In the second embodiment, only the welding positions of the positive electrode connecting member 5A and the negative electrode connecting member 5B and the positive and negative electrode external terminals 4A and 4B are different, and the other processes are the same.

  The joining process will be described in more detail. As shown in FIG. 14, the outer peripheral edge of the battery lid 12 is aligned with the opening 113, and pressurization is performed so that no gap is generated on the mating surface. A laser beam is irradiated and scanned from above the battery lid 12 toward the outer peripheral edge of the battery lid 12, and the battery can 11 and the battery lid 12 are welded.

  As shown in FIG. 15, after injecting the electrolyte from the injection port 20, the injection port 20 is sealed with an injection plug 22, and the outer periphery is laser beam welded to complete the lithium ion secondary battery 30. . As the electrolytic solution, a non-aqueous electrolytic solution in which a lithium salt such as lithium hexafluorophosphate (LiPF6) is dissolved in a carbonic acid ester-based organic solvent such as ethylene carbonate is used.

The secondary battery manufacturing method described above includes a flat side wall 110, a bottom wall 111 defined by the side wall 110 and wider than the side wall 110, and an opening 113 facing the bottom wall 111. In order to seal the can 11 and the opening 113, a battery lid 12 attached to the battery can 11, a power generation element group 6 housed in the battery can and provided with a positive electrode and a negative electrode, and a power generation element group 6 Is housed in the battery can 11, the side wall 110B located in the vicinity of each of the positive electrode current collector 6A and the negative electrode current collector 6B is fixed to the side wall 110B while penetrating and sealing the side wall 110B. A method of manufacturing a secondary battery including a positive electrode having a support portion formed inside a battery can 11 and negative external terminals 4A and 4B,
(A) attaching and fixing the external terminals 4A and 4B to the side wall 110B of the battery can 11 via the sealing material 13;
(B) fixing the connection members 5A and 5B to the positive electrode current collector 6A and the negative electrode current collector 6B of the power generation element group 6;
(C) the step of positioning the power generating element group 6 in the battery can 11 by supporting the connecting members 5A, 5B by the support portions 4AS of the external terminals 4A, 4B;
(D) welding the contact surfaces of the external terminals 4A, 4B and the connection members 5A, 5B from the opening 113 or from the outside of the external terminals 4A, 4B;
(E) attaching the battery lid 12 to the opening 113.

[Fourth Embodiment]
Next, based on FIG. 16, FIG. 17, 4th Embodiment of the secondary battery by this invention is described. In the figure, the same or corresponding parts as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted.

In the fourth embodiment, the shapes of the vertical contact end portions 5AS, 5BS in the support portions 4AS, 4BS, the positive electrode connection member 5A, and the negative electrode connection member 5B in the positive and negative external terminals 4A, 4B of the first embodiment are changed. It is a thing.
16 and 17 representatively show only the positive external terminal 4A side.

  The positive external terminal 4A has a substantially L-shaped cross section. The positive external terminal 4A has a support portion 4AS formed inside the container 10. The support portion 4AS includes a support surface 4AS1 along the depth direction (DH direction), and a projecting piece (load support portion) extending from the bottom side end of the support surface 4AS1 in the direction along the container bottom wall 111 (HH direction). 4AS2. The contact surface 4AT is formed on the support surface 4AS1. The positive external terminal 4 </ b> A has a counterbore 41 and a through hole 20.

  The positive electrode connecting member 5A includes a base portion 5AA extending parallel to the bottom wall 111, a rising portion 5AS1 that is continuous with the base portion 5AA and bent toward the bottom wall 111 along the DH direction, and a bent portion. A load support portion 5AS2 extending from the end portion on the bottom wall 111 side of 5AS1 along the surface on the opening portion 113 side of the projecting piece 4AS2, and a direction of the opening portion 113 along the support surface 4AS1 from the end portion on the side wall 110B side of the load support portion 5AS2 And an opposing portion 5AS3 extending in the direction.

  The support portion 4AS supports the positive electrode connection member 5A on the support surface 4AS1 (contact surface 4AT), thereby positioning the power generating element group 6 before welding in the WH direction and supporting the load support portion 5AS2 by the projecting piece 4AS2. Then, the battery can 11 is positioned in the depth direction (DH direction).

The support surfaces 4AS1, 4BS1 and the opposing portions 5AS3, 5BS3 have a function of positioning the positive and negative current collector portions of the power generation element group 6, and the projecting pieces 4AS2, 4BS2 and the load support portions 5AS2, 5BS2 are power generation element groups 6. The battery can has a function of positioning in the depth direction.
The contact surface 5AT is formed long along the support surface 4AS1 in the facing portion 5AS3, and the contact surface 5AT is laser beam welded to the contact surface 4AT at two locations. Laser beam welding is performed from the outside of the positive electrode external terminal 4A.
As a result, the welding operation can be performed after the position of the power generating element group 6 is reliably set, and the work efficiency and the positioning accuracy can be improved.

In the fourth embodiment, since the contact lengths of the contact surfaces 4AT and 5AT are long, welding can be performed at a plurality of locations, and the welding strength can be increased.
Further, the positive and negative external terminals 4A and 4B are simpler than the third embodiment, and the manufacturing cost can be reduced.
Further, as shown in FIG. 17, since the collar portion 26 of the plug member 22 is accommodated in the counterbore 41, the collar portion 26 does not protrude from the surface of the external terminal 4A, and the weld bead does not bulge from the surface of the external terminal. .

[Fifth Embodiment]
Next, a fifth embodiment of the secondary battery according to the present invention will be described with reference to FIG. In the figure, the same or corresponding parts as those in the fourth embodiment are denoted by the same reference numerals, and description thereof is omitted.

In the fifth embodiment, the facing portion 5AS3 in the fourth embodiment is formed short, while the contact surfaces 5AT, 5BT are formed on the bottom wall 111 side surface of the load support portions 5AS2, 5BS2, The contact surfaces 4AT and 4BT are formed on the surface of the protrusions 4AS2 and 4AS2 on the opening 113 side.
FIG. 18 representatively shows only the positive electrode terminal (external terminal) 4A side.

In the fifth embodiment, laser beam welding can be performed between the contact surfaces 4AT, 5AT, 4BT, 5BT from the opening 113 side. As in the fourth embodiment, the external terminals 4A, 4B It should be used when welding from the outside is not appropriate.
Other configurations and effects are the same as those of the fourth embodiment.

  The support surfaces 4AS1, 4BS1 and the facing portions 5AS3, 5BS3 have a function of positioning the power generation element group 6 in the positive and negative current collector direction, and the projecting pieces 4AS2, 4BS2 and the load support portions 5AS2, 5BS2 are power generation element groups. 6 has a function of positioning in the depth direction of the battery can.

[Sixth Embodiment]
Next, a sixth embodiment of the secondary battery according to the present invention will be described with reference to FIG. In the figure, the same or corresponding parts as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted.

In the sixth embodiment, the configuration of the external terminals 4A and 4B in the first embodiment is changed, and the welding position is changed.
FIG. 19 representatively shows only the positive electrode terminal (external terminal) 4A side.

  The external terminal 4A is formed thick, and a support portion 4AS protruding inside the container 10 is formed. The support portion 4AS has a substantially rectangular cross-sectional shape along the depth direction (DH direction) of the battery can 1. A caulking portion 4AD is formed in a portion of the external terminal 4A outside the container 10, and a sealing member 132 is inserted between the terminal mounting opening 115 and the external terminal 4A. The external terminal 4A is inserted into the terminal mounting opening 115 in a state where the sealing member 132 is fitted to the periphery, and then the caulking portion 4AD is caulked to pressurize the sealing member 132 while surrounding the external terminal 4A. Is sealed.

  The sealing performance by the sealing member 132 thus pressurized and fixed is stronger than the sealing by the transfer mold (first to fourth embodiments), and the external terminal 4A by caulking. The fixing strength is also higher than that of the above embodiment.

  Laser beam welding of the connecting members 5A and 5B and the positive and negative terminals 4A and 4B is performed from the opening 113 side to the mutual contact surfaces 5AT and 4AT and the contact surfaces 5BT and 4BT.

  In addition to the effects of the first embodiment, the sixth embodiment has an effect that the fixing strength and sealing performance of the external terminals 4A and 4B are high. Further, laser beam welding can be performed from the opening 113 side. The contact surfaces 4AT and 4BT and the contact end portions 5AS and 5BS have a function of positioning the power generation element group 6 in the direction between the external terminals.

  In this embodiment, although the lithium ion secondary battery 30 was illustrated as a secondary battery, this invention is not limited to this, It can apply to a secondary battery generally. Moreover, although lithium manganate was illustrated as a positive electrode active material and graphite was illustrated as a negative electrode active material, respectively, this invention is not restrict | limited to this, The active material normally used for a lithium ion secondary battery can also be used. The positive electrode active material is a material capable of inserting and removing lithium ions, and a lithium transition metal composite oxide in which a sufficient amount of lithium ions has been inserted in advance may be used. A material in which a part of lithium or a transition metal is substituted or doped with an element other than those may be used. Furthermore, there is no restriction | limiting in particular also about crystal structure, You may have any crystal structure of a spinel system, a layer system, and an olivine system.

  On the other hand, as the negative electrode active material other than graphite, for example, carbon materials such as coke and amorphous carbon can be mentioned, and the particle shape is also particularly limited such as scaly, spherical, fibrous, and massive. It is not a thing.

  Furthermore, the present invention is not particularly limited with respect to the conductive material and binder exemplified in the present embodiment, and any of those normally used in lithium ion secondary batteries can be used. Examples of binders that can be used in other embodiments include polytetrafluoroethylene, polyethylene, polybutadiene, butyl rubber, nitrile rubber, styrene-butadiene rubber, polysulfide rubber, nitrocellulose, cyanoethyl cellulose, various latexes, acrylonitrile, and vinyl fluoride. , Polymers such as vinylidene fluoride, propylene fluoride, and chloroprene fluoride, and mixtures thereof.

Furthermore, in the present embodiment, a non-aqueous electrolyte solution in which LiPF ₆ is dissolved in an ethylene carbonate-based organic solvent such as ethylene carbonate is exemplified, but a non-aqueous electrolyte in which a general lithium salt is used as an electrolyte and this is dissolved in an organic solvent. An electrolytic solution may be used, and the present invention is not particularly limited to the lithium salt or organic solvent used. For example, as the electrolyte, LiClO ₄ , LiAsF ₆ , LiBF ₄ , LiB (C ₆ H ₅ ) ₄ , CH ₃ SO ₃ Li, CF ₃ SO ₃ Li, or a mixture thereof can be used. As the organic solvent, diethyl carbonate, propylene carbonate, 1,2-diethoxyethane, γ-butyrolactone, sulfolane, propionitrile, or a mixed solvent in which two or more of these are mixed can be used.
Since the present invention provides a secondary battery that reduces internal resistance and can be easily assembled, and contributes to the manufacture and sale of secondary batteries, it has industrial applicability.

4A Positive external terminal 4B Negative external terminal 4AT, 4BT Contact surface 4AS, 4BS Support part
5A Positive connection member 5B Negative connection member 5AT, 5BT Contact surface 5AS, 5BS Vertical contact end
6 Power generation element group 6A Cathode current collector
6B Negative electrode current collector 6RA Positive electrode uncoated part 6RB Negative electrode uncoated part 10 Container
11 Battery can 12 Battery cover
20 Injection port 22 Injection plug (plug member)
26 Collar part 41 Counterbore 110B Short belt side wall 111 Bottom wall 113 Opening part 115 Terminal mounting opening

Claims (7)

A battery container comprising a flat bottomed battery can having an opening at the top and a side wall at the side, and a battery lid for sealing the opening;
A power generation element group housed in the battery container and having a positive electrode, a negative electrode, a positive electrode current collector, and a negative electrode current collector,
A positive electrode external terminal and a negative electrode external terminal that are attached to the side wall of the battery can, and on the inside of the battery container, a current collector connection surface to which the positive electrode current collector and the negative electrode current collector are connected, and
A positive electrode connecting member that connects the positive electrode current collector and the positive electrode external terminal; and a negative electrode connecting member that connects the negative electrode current collector and the negative electrode external terminal;
The secondary battery, wherein the positive electrode external terminal and the positive electrode connecting member, and the negative electrode external terminal and the negative electrode connecting member are fixed by welding from the outside of each external terminal or from the opening side. The secondary battery according to claim 1,
The side wall has a rectangular frame shape in which a pair of long belt-shaped side walls and a pair of short belt-shaped side walls are continuously formed, and the external terminals are respectively fixed to the pair of short belt-shaped side walls,
Each connection member includes a base extending in parallel with the bottom wall of the battery can, and a contact end formed along the current collector connection surface while continuing to the base.
A secondary battery, wherein a contact surface between the connection member and the contact end is fixed by welding. The secondary battery according to any one of claims 1 to 3,
The secondary battery further comprising a horizontal positioning means for positioning the power generation element group in the direction of the positive and negative current collector. The secondary battery according to claim 3,
The horizontal positioning means is provided on the connection member and the external terminal,
The connecting member and the external terminal are respectively formed with contact surfaces that contact each other in the direction of the positive / negative current collector, and position the power generation element group in the direction of the positive / negative current collector. Secondary battery. The secondary battery according to any one of claims 1 to 3,
A secondary battery further comprising depth direction positioning means for positioning the power generation element group in the depth direction of the battery can. The secondary battery according to claim 5,
The battery can depth direction positioning means is provided on the connection member and the external terminal,
2. The secondary battery according to claim 1, wherein the connecting member and the external terminal are respectively formed with contact surfaces that contact each other in the battery depth direction to position the power generation element group in the battery depth direction. A battery can having a flat side wall, a bottom wall defined by the side wall and wider than the side wall, and an opening facing the bottom wall, and the battery can for sealing the opening A battery lid attached to the battery can, a power generation element group housed in the battery can and provided with a positive electrode and a negative electrode, and when the power generation element group is housed in the battery can, A positive electrode having a support portion formed inside the battery can and a negative electrode external terminal connected to the side wall located in the vicinity of each of the current collector portions of the negative electrode, being fixed to the side wall while being sealed through the side wall. A method for manufacturing a secondary battery comprising:
Attaching and fixing the external terminal to the side wall of the battery can via a sealing material;
Fixing a connection member to each of the positive electrode current collector and the negative electrode current collector of the power generation element group;
Positioning the power generation element group in the battery can by supporting the connection member by the support portion of the external terminal;
Welding the contact surface between the external terminal and the connecting member from the opening or from the outside of the external terminal;
And a step of attaching the battery lid to the opening.

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