JP2016001561A - Method and device for manufacturing power storage device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method and a device for manufacturing a power storage device, capable of simply and electrically connecting a conductive member and a conductive part group.SOLUTION: Disclosed is a method of manufacturing a secondary battery, in which a conductive member 22 and a negative electrode tab group 14d of an electrode assembly are electrically connected. In a formation process of the manufacturing method, every time one layer is stacked on a negative electrode 14, a negative electrode tab 14c of the stacked negative electrode 14 is welded to the conductive member 22 and the negative electrode tab 14 adjacent to each other.

Description

  The present invention relates to a method for manufacturing a power storage device and a device for manufacturing a power storage device.

  Conventionally, vehicles such as EVs (Electric Vehicles) and PHVs (Plug in Hybrid Vehicles) have been mounted with lithium-ion secondary batteries or nickel-hydrogen secondary batteries as power storage devices that store power supplied to electric motors and the like. . This type of secondary battery has an electrode assembly in which electrodes having tab-shaped current collectors are stacked in layers over a plurality of layers.

  For example, as shown in Patent Document 1, a current collecting portion group in which current collecting portions of each electrode overlap each other and a conductive member such as an electrode terminal are joined by laser welding or resistance welding. In patent document 1, while dividing a current collection part group into plurality and welding each to a conductive member, welding strength is improved compared with the case where all the current collection parts are welded to a conductive member collectively. ing.

JP 2008-66170 A

  However, in Patent Document 1, the electrode assembly is formed by stacking electrodes in layers, and then the current collecting unit group is further divided into a plurality of parts, and the manufacturing process of the secondary battery becomes complicated, or the current collecting unit group There is a possibility that the structure as a manufacturing apparatus may be complicated, such as requiring a jig or apparatus for dividing the structure.

  The present invention has been made paying attention to the problems existing in the above-described prior art, and an object of the present invention is to provide a method of manufacturing a power storage device capable of easily electrically connecting a conductive member and a current collector unit, and a power storage The object is to provide a device manufacturing apparatus.

  A method of manufacturing a power storage device that solves the above problem includes an electrode assembly in which electrodes are stacked in layers, and a conductive member, and the electrode assembly includes a current collector portion of the electrodes stacked in layers and an edge. A method of manufacturing a power storage device in which the conductive member and the current collector portion group are electrically connected to each other, each time the electrode is stacked one layer. Alternatively, every time a plurality of layers of the electrodes are stacked, the current collector portion of the stacked electrodes is welded.

  According to this configuration, each time one electrode is stacked, or each time a plurality of electrodes are stacked, the current collecting part of the stacked electrodes is welded. The member can be electrically connected. For this reason, the conductive member and the current collecting unit group can be electrically connected more easily than the conventional structure in which the current collecting unit group is further divided into a plurality of parts and welded to the conductive member after the electrode assembly is formed. Can connect.

  About the method for manufacturing the power storage device, each time the electrode is stacked one layer or each time the electrode is stacked a plurality of layers, the tip of the current collector is shifted in a predetermined direction in order and the tip of the current collector is It is preferable to weld.

  According to this configuration, since the tip end portion of the current collecting part arranged in a shifted manner is welded, the energy required for welding is increased as compared with the case where all the current collecting parts are repeatedly welded at the same part. It is possible to easily connect the conductive member and the current collecting unit group.

  About the manufacturing method of the said electrical storage apparatus, every time the said electrode is piled up one layer, or every time the said electrode is laminated | stacked several layers, the front-end | tip of the said current collection part is shifted and arranged in order toward the base end of the said current collection part. At the same time, it is preferable to laser weld the tip of the current collector.

  According to this configuration, since the tip of the current collecting part arranged in a shifted manner is laser-welded, the laser intensity required for welding is compared with the case where all the current collecting parts are repeatedly laser-welded at the same part. Can be suppressed, and the conductive member and the current collecting portion group can be electrically connected easily.

  According to this configuration, the electrode assembly includes an electrode assembly in which the electrodes overlap each other in layers, and the conductive member. The electrode assembly includes a collector in which the current collecting portions of the electrodes overlap in layers and protrudes from the edges. A power storage device manufacturing apparatus having a power unit group, wherein the conductive member and the current collector unit group are electrically connected, wherein the electrodes are stacked in layers to form an electrode assembly And a welding device that welds the current collecting portions of the stacked electrodes each time one layer of the electrodes is stacked by the forming device or each time a plurality of layers of the electrodes are stacked. And

  According to this configuration, since the current collecting part of the stacked electrodes can be welded each time one electrode is stacked or a plurality of electrodes are stacked, the current collecting part group and the conductive member are formed while forming the electrode assembly. Can be electrically connected. For this reason, the conductive member and the current collecting unit group can be electrically connected more easily than the conventional structure in which the current collecting unit group is further divided into a plurality of parts and welded to the conductive member after the electrode assembly is formed. Can connect.

  According to the present invention, the conductive member and the current collecting unit group can be electrically connected easily.

The perspective view which shows a secondary battery typically. The perspective view which shows typically the decomposed | disassembled electrode assembly. FIG. 1 is a sectional view taken along line 1-1 shown in FIG. (A) is sectional drawing which shows typically the welding part of a negative electrode tab group and an electroconductive member, (b) is sectional drawing which expands and shows a part of (a), (c) is a top view of (a). . The front view which shows the manufacturing apparatus of a secondary battery typically. (A) is a front view schematically showing an adsorption pad, (b) is also a bottom view, and (c) is a plan view showing a laminated body on a laminated table. (A) And (b) is a schematic diagram for demonstrating a formation process. (A) And (b) is a schematic diagram for demonstrating a formation process. (A) And (b) is a schematic diagram for demonstrating a formation process. (A) And (b) is a schematic diagram for demonstrating a formation process. (A) And (b) is a schematic diagram for demonstrating the formation process in another embodiment. (A) And (b) is a schematic diagram for demonstrating the formation process in another embodiment.

Hereinafter, an embodiment of a secondary battery manufacturing method and a secondary battery manufacturing apparatus will be described.
As shown in FIG. 1, a secondary battery 10 as a power storage device has a rectangular parallelepiped case 11 made of metal. The case 11 is made of, for example, aluminum or aluminum alloy. The case 11 includes a bottomed square cylindrical case main body 11a and a lid 11b that closes an opening of the case main body 11a. An electrode assembly 12 is accommodated in the case 11. The electrode assembly 12 is impregnated with an electrolyte (electrolytic solution) not shown. The secondary battery 10 of this embodiment is a lithium ion secondary battery.

  The electrode assembly 12 has a substantially rectangular parallelepiped shape as a whole, and is a stacked electrode assembly in which a positive electrode 13 and a negative electrode 14 are alternately stacked over a plurality of layers with a separator 15 interposed therebetween. is there. The positive electrode 13 and the negative electrode 14 have a substantially rectangular sheet shape. The positive electrode 13 and the negative electrode 14 are insulated from each other by the separator 15. In the following description, the direction in which the electrodes 13 and 14 overlap in the electrode assembly 12 is simply referred to as “stacking direction DS”.

  As shown in FIG. 2, the positive electrode 13 includes a substantially rectangular metal foil 13a for a positive electrode, an active material layer 13b that covers a part of both surfaces thereof and includes a positive electrode active material, and a metal foil 13a. And a positive electrode tab 13c as a current collector protruding from one edge (one side). The metal foil 13a is, for example, an aluminum foil. The positive electrode tab 13c of this embodiment is a part of the metal foil 13a that is not covered with the active material layer 13b. All the positive electrodes 13 constituting the electrode assembly 12 have the same shape and the same configuration. That is, the length of the positive electrode tab 13c of each positive electrode 13 along the protruding direction D1 is the same (or substantially the same).

  The negative electrode 14 includes a substantially rectangular metal foil 14 a, an active material layer 14 b that covers a part of both surfaces of the metal foil 14 a and contains an active material for the negative electrode, and one edge (one side) of the metal foil 14 a. And a negative electrode tab 14c as a protruding current collector. The metal foil 14a is, for example, a copper foil. The negative electrode tab 14c of the present embodiment is a part of the metal foil 14a that is not covered with the active material layer 14b. All the negative electrodes 14 constituting the electrode assembly 12 have the same shape and the same configuration. That is, the negative electrode tab 14c of each negative electrode 14 has the same (or substantially the same) length along the protruding direction D1.

  The separator 15 is a bag-like separator in which the edges of the rectangular sheet-like separators 15a and 15b are joined together, and the positive electrode 13 is accommodated in the separator 15 with the positive electrode tab 13c protruding. .

  As shown in FIG. 1, the electrode assembly 12 protrudes from the edge portion 12 a of the electrode assembly 12 by laminating the plurality of positive electrodes 13, and the positive electrode tabs 13 c of the positive electrode 13 overlap each other in layers. A positive electrode tab group 13d as a current collecting unit group. In addition, the electrode assembly 12 has a plurality of negative electrodes 14 stacked so that the electrode assembly 12 protrudes from the edge 12a of the electrode assembly 12 and the negative electrode tabs 14c of the negative electrode 14 overlap each other in layers. As a negative electrode tab group 14d.

  Further, the secondary battery 10 includes a positive electrode terminal 17 fixed to the lid 11 b so as to protrude outside the case 11 and a negative electrode terminal 18 fixed to the lid 11 b so as to protrude outside the case 11. The positive electrode terminal 17 and the negative electrode terminal 18 are insulated from the lid 11b by an annular insulating member 19.

  As shown in FIG. 3, the secondary battery 10 includes a metal conductive member 22 that electrically connects the electrode assembly 12 (negative electrode tab group 14 d) and the negative electrode terminal 18. The conductive member 22 is made of, for example, copper. The negative electrode terminal 18 and the conductive member 22 are electrically connected at the base end portion of the conductive member 22. The negative electrode tab group 14d is in a state in which all the negative electrode tabs 14c are gathered to one end surface 12b side of both end surfaces of the electrode assembly 12 in the stacking direction DS and is bent so as to extend along the edge portion 12a. In this state, it is welded to the tip of the conductive member 22.

  In addition, the secondary battery 10 includes a metal conductive member 21 that electrically connects the electrode assembly 12 (positive electrode tab group 13 d) and the positive electrode terminal 17. The conductive member 21 is made of, for example, aluminum. The positive electrode terminal 17 and the conductive member 21 are electrically connected at the base end portion of the conductive member 21. Further, the positive electrode tab group 13d is a state in which all the positive electrode tabs 13c are gathered to the end surface 12b side of the electrode assembly 12 and is bent so as to extend along the edge portion 12a. It is welded to the tip.

  Hereinafter, the joint structure between the negative electrode tab group 14d and the conductive member 22 will be described in detail. Note that the bonding structure between the positive electrode tab group 13d and the conductive member 21 is the same as that of the negative electrode tab group 14d and the conductive member 22, and thus detailed description thereof is omitted.

  As shown in FIGS. 4A to 4C, in the negative electrode tab group 14d, each negative electrode tab 14c has a sloped shape at the tip of the negative electrode tab group 14d, and a stepped shape in an enlarged cross section. Are stacked. That is, the shape of the negative electrode tab group 14d is a stepped shape because the tip of the negative electrode tab 14c is sequentially shifted in the protruding direction D1 for each layer. In other words, with respect to the tip of the negative electrode tab 14c that protrudes most in the protruding direction D1, the tip of the negative electrode tab 14c is sequentially shifted in the direction opposite to the protruding direction D1 (direction toward the edge 12a) for each layer. It can also be grasped. In the present embodiment, the direction opposite to the protruding direction D1 is the predetermined direction. In addition, that the shape of a front-end | tip part is a slope shape (inclined surface) means that the virtual plane which contacts each negative electrode tab 14c turns into an inclined surface.

  And each negative electrode tab 14c is welded by the front-end | tip part, respectively. More specifically, the negative electrode tab 14c adjacent to the conductive member 22 is welded to the conductive member 22 at the tip. The other negative electrode tab 14c is welded to the adjacent negative electrode tab 14c at the tip. As will be described later, in the present embodiment, each negative electrode tab 14c is welded (laser welding) using a welding laser. In the following description, in each negative electrode tab 14c, a portion welded to the adjacent negative electrode tab 14c or the conductive member 22 is referred to as a welded portion 14e.

  Next, the manufacturing apparatus 30 for the secondary battery 10 will be described with reference to FIG. The manufacturing apparatus 30 according to this embodiment includes a forming apparatus 60 that forms the electrode assembly 12 by stacking the electrodes 13 and 14 in layers, and each time the electrodes 13 and 14 are stacked by the forming apparatus 60, the stacking is performed. A welding device 70 for welding the tabs of the electrodes, and a control device 80 for controlling the manufacturing device 30. Details will be described below.

  The forming apparatus 60 includes a box-shaped positive electrode storage unit 31 that stores a plurality of positive electrodes 13 stored in the separator 15 in a state where the positive electrode tabs 13c are aligned in the same direction. In addition, the manufacturing apparatus 30 includes a box-shaped negative electrode storage portion 32 that stores a plurality of negative electrodes 14 in a stacked state with the negative electrode tabs 14c aligned in the same direction.

  The forming apparatus 60 includes a stacked table 33 on which the positive electrode 13 and the negative electrode 14 accommodated in the separator 15 are placed. The laminated table 33 is disposed between the positive electrode storage unit 31 and the negative electrode storage unit 32. The laminated table 33 is supported on a support base 39.

  As shown in FIG. 6C, in the present embodiment, the positive electrode 13 and the negative electrode 14 are arranged such that the positive electrode tabs 13c are arranged in a line along the stacking direction DS and do not overlap with the positive electrode tabs 13c. The negative electrode tabs 14c are stacked on the stacking table 33 so as to be arranged in a row along the stacking direction DS. And in the lamination | stacking table 33, the positive electrode 13 accommodated in the separator 15 and the negative electrode 14 are laminated | stacked alternately, and the laminated body 23 is formed.

  In addition, a first fixing portion 33 a that fixes the conductive member 21 is provided on the upper surface of the stacking table 33 so as to correspond to the position where the positive electrode tabs 13 c are stacked. In addition, a second fixing portion 33b for fixing the conductive member 22 is provided on the upper surface of the stacking table 33 so as to correspond to the position where the negative electrode tab 14c is stacked. Each fixing | fixed part 33a, 33b is a clamp mechanism etc. which fix each electroconductive member immovably, for example, the recessed part into which an electroconductive member is each fitted, for example.

  Moreover, as shown in FIG. 5, the positive electrode accommodating part 31, the negative electrode accommodating part 32, and the lamination | stacking table 33 are located in a line with the same line. The forming apparatus 60 includes a guide rail 35 disposed above the positive electrode storage unit 31, the negative electrode storage unit 32, and the laminated table 33.

  The forming device 60 includes a positive electrode transfer device 40 that can move along the guide rail 35. The positive electrode transfer device 40 includes a positive electrode adsorption device 41 that adsorbs the positive electrode 13 together with the separator 15, and a first positive electrode elevation device 44 a that raises and lowers the positive electrode adsorption device 41. The first positive / lower lift device 44a is, for example, an air cylinder. In the forming device 60, the positive electrode adsorption device 41 is moved up and down by controlling the operation of the first positive electrode lifting device 44a. The positive electrode adsorption device 41 includes a positive electrode adsorption pad 42 and a positive electrode pump 43 that generates a suction force to the positive electrode adsorption pad 42.

  As shown in FIGS. 6A and 6B, the positive electrode adsorption surface 42a of the positive electrode adsorption pad 42 has a rectangular shape, and suction holes 47a to 47e are provided in the positive electrode adsorption surface 42a. . In the positive electrode adsorption device 41, by driving the positive electrode pump 43, the suction holes 47a to 47e can be depressurized to generate an adsorption force.

  Further, as indicated by a two-dot chain line in the drawing, a positive electrode tab pressing device 45 for pressing the positive electrode tab 13 c is disposed at the edge of the positive electrode suction pad 42. The positive electrode tab pressing device 45 includes a tab pressing portion 46 that presses the positive electrode tab 13 c and a second positive electrode lifting device 44 b that lifts and lowers the tab pressing portion 46 relative to the positive electrode suction pad 42. The second positive electrode lifting device 44b is, for example, a solenoid.

  The tab presser portion 46 has a base end connected to the second positive electrode lifting device 44b and an arm portion 46a having a reverse L-shape when viewed from the front, and a presser connected to the distal end of the arm portion 46a. Part 46b. In a plan view, the shape of the pressing portion 46b is a rectangular frame shape having a rectangular weld hole 46c extending along the protruding direction D1 of the positive electrode tab 13c.

  In a plan view, the pressing portion 46b is larger than the positive electrode tab 13c in both the protruding direction D1 and the width direction D2 orthogonal to the directions D1 and DS. Moreover, the welding hole 46c is smaller than the positive electrode tab 13c in the width direction D2 by planar view.

  As shown in FIG. 5, the forming device 60 includes a negative electrode transfer device 50 that can move along the guide rail 35. The negative electrode transfer device 50 includes a negative electrode adsorption device 51 that adsorbs the negative electrode 14, and a first negative electrode elevating device 54 a that raises and lowers the negative electrode adsorption device 51. The first negative electrode elevating device 54a is, for example, an air cylinder. In the forming device 60, the negative electrode adsorption device 51 is moved up and down by controlling the operation of the first negative electrode lifting device 54a. The negative electrode adsorption device 51 includes a negative electrode adsorption pad 52 and a negative electrode pump 53 that generates a suction force on the negative electrode adsorption pad 52.

  As shown in FIGS. 6A and 6B, similarly to the positive electrode suction pad 42, the negative electrode suction pad 52a has a rectangular shape, and the negative electrode suction surface 52a has a suction hole 57a. -57e are arranged. In the negative electrode adsorption device 51, by driving the negative electrode pump 53, the suction holes 57a to 57e can be depressurized to generate an adsorption force.

  In addition, a negative electrode tab pressing device 55 for pressing the negative electrode tab 14 c is disposed at the edge of the negative electrode adsorption pad 52. The negative electrode tab pressing device 55 includes a tab pressing portion 56 that presses the negative electrode tab 14 c, and a second negative electrode lifting device 54 b that lifts and lowers the tab pressing portion 56 relative to the negative electrode suction pad 52. The second negative electrode elevating device 54b is, for example, a solenoid.

  The tab holding portion 56 has a base end connected to the second negative electrode lifting device 54b and an arm portion 56a having a reverse L-shape when viewed from the side, and a presser connected to the distal end of the arm portion 56a. Part 56b. In plan view, the shape of the presser portion 56b is a rectangular frame shape having a rectangular weld hole 56c extending along the protruding direction D1 of the negative electrode tab 14c.

  In a plan view, the pressing portion 56b is larger than the negative electrode tab 14c in both the protruding direction D1 and the width direction D2. Further, the weld hole 56c is smaller than the negative electrode tab 14c in the width direction D2 in plan view.

  As shown in FIG. 5, the welding apparatus 70 is a laser welding machine capable of welding by irradiating a laser beam 71 to the positive electrode tab 13 c and the negative electrode tab 14 c. The welding apparatus 70 can change the irradiation position of the laser beam 71 by driving a built-in mirror, for example.

  The control device 80 controls operations of the positive electrode pump 43, the positive electrode lifting devices 44 a and 44 b, the negative electrode pump 53, the negative electrode lifting devices 54 a and 54 b, and the welding device 70. The positive electrode pump 43, the positive electrode lifting devices 44 a and 44 b, the negative electrode pump 53, the negative electrode lifting devices 54 a and 54 b, and the welding device 70 are signal-connected to the control device 80. The control device 80 includes a storage unit (not shown). In this storage unit, control programs for the positive electrode pump 43, the positive electrode lifting devices 44a and 44b, the negative electrode pump 53, the negative electrode lifting devices 54a and 54b, and the welding device 70 are stored.

  Next, a method for manufacturing the secondary battery 10 (electrode assembly 12) using the manufacturing apparatus 30 will be described together with its operation. The manufacturing method of the secondary battery 10 includes a forming step of forming the electrode assembly 12 by laminating and welding a plurality of positive electrodes 13 (encased in a separator 15) and a plurality of negative electrodes 14. In the forming step, the control device 80 executes the control program stored in the storage unit, thereby causing the positive electrode pump 43, the positive electrode lifting devices 44a and 44b, the negative electrode pump 53, the negative electrode lifting devices 54a and 54b, and The welding apparatus 70 is operated. In performing the forming process, conductive members are fixed to the fixing portions 33a and 33b of the stacking table 33, respectively.

  In the forming step, the negative electrode transfer device 50 is moved onto the negative electrode storage portion 32, and the negative electrode suction pad 52 is lowered by the first negative electrode lifting device 54 a and moved into the negative electrode storage portion 32. Then, the negative electrode pump 53 is driven to generate a suction force on the negative electrode suction pads 52 (suction holes 57 a to 57 e), thereby adsorbing the uppermost negative electrode 14 of the negative electrode storage portion 32.

  Next, the negative electrode suction pad 52 is raised by the first negative electrode lifting / lowering device 54 a, and the negative electrode transfer device 50 is moved along the guide rail 35 onto the stacking table 33 as it is. Next, the negative electrode suction pad 52 is lowered toward the laminated table 33 by the first negative electrode lifting device 54 a.

  As shown in FIGS. 7A and 7B, the first negative electrode 14 is laminated on the lamination table 33. Then, the negative electrode tab 14 c is pressed and fixed to the conductive member 22 by lowering the tab pressing portion 56 toward the laminated table 33 by the second negative electrode lifting device 54 b. Next, as shown in black in the drawing, a laser beam 71 is irradiated from the weld hole 56c to the tip of the negative electrode tab 14c to melt and solidify to form a weld 14e, and the negative electrode tab 14c. And the conductive member 22 are welded. Thereafter, the negative electrode suction pad 52 is raised by the first negative electrode lifting / lowering device 54 a, and the negative electrode transfer device 50 is moved from the stacking table 33.

  Next, as shown in FIG. 5, the positive electrode 13 accommodated in the separator 15 is laminated on the lamination table 33 (lamination body 23). In the positive electrode transfer device 40, the positive electrode suction pad 42 is lowered by the first positive electrode lifting device 44 a and moved into the positive electrode storage portion 31. Then, the positive electrode pump 43 is driven to generate a suction force at the positive electrode suction pads 42 (suction holes 47 a to 47 e), thereby adsorbing the positive electrode 13 accommodated in the separator 15.

  Next, the positive electrode suction pad 42 is raised by the first positive electrode lifting / lowering device 44 a, and the positive electrode transfer device 40 is moved along the guide rail 35 onto the stacking table 33 as it is. Next, the positive electrode suction pad 42 is lowered toward the stacking table 33 by the first positive electrode lifting device 44 a.

  Then, as shown in FIGS. 8A and 8B, the first positive electrode 13 housed in the separator 15 is stacked on the stacked body 23 on the stacking table 33. Then, the positive electrode tab 13 c is pressed and fixed to the conductive member 21 by lowering the tab pressing portion 46 toward the laminated table 33 by the second positive electrode lifting device 44 b. Next, the laser beam 71 is irradiated from the welding hole 46c to the tip of the positive electrode tab 13c to melt and solidify to form a welded portion, and the positive electrode tab 13c and the conductive member 21 are welded. Thereafter, the positive electrode suction pad 42 is raised by the first positive electrode lifting device 44 a and the positive electrode transfer device 40 is moved from the stacking table 33.

  Next, similarly to the first negative electrode 14, the second negative electrode 14 is laminated on the laminate 23 by the negative electrode transfer device 50. And the negative electrode tab 14c is pressed by making the tab holding part 56 descend | fall toward the lamination | stacking table 33 by the raising / lowering apparatus 54b for 2nd negative electrodes, and it fixes with respect to the 1st negative electrode tab 14c.

  Here, in the laminated body 23, the base end portion of the negative electrode tab 14 c is formed by stacking the positive electrode 13 between the negative electrodes 14 or the thickness of the active material layer 14 b. It is located above the negative electrode tab 14c. For this reason, when the second negative electrode tab 14c is pressed by the tab pressing portion 56, the leading end of the second negative electrode tab 14c is shifted to the proximal side from the leading end of the first negative electrode tab 14c. Be placed.

  Next, as shown in black in the drawing, a laser beam 71 is applied to the tip of the newly stacked negative electrode tab 14c to form a welded portion 14e, and the first negative electrode tab 14c and Weld. That is, the welded portion 14e in the second negative electrode tab 14c is shifted to the proximal end side of the negative electrode tab 14c with respect to the welded portion 14e in the first negative electrode tab 14c. Thereafter, the negative electrode suction pad 52 is raised by the first negative electrode lifting / lowering device 54 a, and the negative electrode transfer device 50 is moved from the stacking table 33.

  Next, similarly to the first positive electrode 13, the second positive electrode 13 is stacked on the stacked body 23 by the positive electrode transfer device 40. And the positive electrode 13 is pressed by lowering the tab holding part 46 toward the lamination | stacking table 33 by the raising / lowering apparatus 44b for 2nd positive electrodes, and it fixes with respect to the 1st positive electrode tab 13c. Next, in the same manner as the second negative electrode tab 14c, the front end portion of the newly stacked positive electrode tab 13c is irradiated with laser light 71, and the proximal end side of the welded portion of the first positive electrode tab 13c. A welded portion is formed at a position shifted to, and welded to the first positive electrode tab 13c.

  Thereafter, as shown in FIGS. 9A and 9B and FIGS. 10A and 10B, the negative electrode 14 and the positive electrode 13 wrapped in the separator 15 are attached to the laminate 23. Laminate alternately. At this time, each time the electrodes 13 and 14 are stacked, the thickness of the stacked body 23 becomes gradually thicker than the thickness of the negative electrode tab group 14 d, so that the negative electrode tab 14 c is pressed by the tab pressing portion 56. As a result, the negative electrode tabs 14c are sequentially displaced toward the base end side. In the forming process, each time the negative electrode tab 14c is newly laminated, that is, every time one negative electrode 14 is stacked, the laser beam 71 is irradiated, and the tip of the negative electrode tab 14c of the negative electrode 14 stacked immediately before is irradiated. Weld the parts. For this reason, the newly formed welded portion 14e is sequentially shifted toward the base end side of the negative electrode tab 14c.

  Here, for example, when the negative electrode tabs 14c are collectively welded using spot welding, an increase in the number of stacked negative electrode tabs 14c can be accommodated by an increase in current. However, the thermal load is proportional to the square of the current. For this reason, the bad influence by the heat at the time of welding increases more than the increase in the number of laminated layers. Laser welding has the same problem. On the other hand, in the manufacturing apparatus 30 of the present embodiment, the intensity necessary for welding one negative electrode tab 14 c can be set as the intensity (output) of the laser beam 71. That is, for example, the intensity of the laser light 71 can be set smaller than in the case where all the negative electrode tabs 14c are collectively welded to the conductive member 22. For this reason, the heat_generation | fever by irradiation of the laser beam 71 can be reduced and it can suppress having a bad influence on the active material layers 13b and 14b by the heat_generation | fever by laser welding.

  In addition, when a large number of negative electrode tabs 14c are collectively laser-welded, the state in which the negative electrode tabs 14c melt differs between the surface side and the opposite side, and variations in conductivity (electrical resistance) tend to occur between the tabs. On the other hand, in the manufacturing apparatus 30 of this embodiment, since the negative electrode tabs 14c are welded one by one with the laser beam 71, the state of the welded portion is less likely to vary, and the risk of variation in electrical resistance is reduced. I can do it.

  In the manufacturing apparatus 30, the negative electrode tab 14 c is welded every time one (one layer) of the negative electrode 14 is overlapped, so that the negative electrode tab group 14 d is divided into a plurality of parts after the electrode assembly 12 is completed. Compared with the configuration, it is possible to prevent the manufacturing process from becoming complicated and the configuration as the manufacturing apparatus 30 from becoming complicated. Since the same applies to the lamination and welding of the positive electrode tab 13c, the detailed description thereof is omitted.

  Then, when a predetermined number of the positive electrodes 13 and the negative electrodes 14 are laminated and the formation process is completed, the electrode assembly 12 is completed. Thereafter, the positive electrode tab group 13d and the negative electrode tab group 14d are bent along the edge 12a of the electrode assembly 12 to be in the state shown in FIGS. The conductive members 21 and 22 are electrically connected to the terminals 17 and 18, respectively. And the electrode assembly 12 is accommodated in the case 11 with the electrolyte, and the secondary battery 10 is completed.

Therefore, according to the above embodiment, the following effects can be obtained.
(1) Every time one layer of the negative electrode 14 is stacked, the negative electrode tab 14c of the stacked negative electrode 14 is welded, so that the negative electrode tab group 14d and the conductive member 22 are electrically connected while forming the electrode assembly 12. Can connect. For this reason, the conductive member 22 and the negative electrode tab group 14d can be easily combined with the conventional structure in which the negative electrode tab group 14d is further divided into a plurality of parts and welded to the conductive member 22 after the electrode assembly 12 is formed. Can be connected electrically. The same applies to the connection between the conductive member 21 and the positive electrode tab group 13d.

  (2) In the present embodiment, since the tip portions of the negative electrode tabs 14c arranged in a shifted manner are welded, the energy required for welding is increased compared to the case where all the negative electrode tabs 14c are repeatedly welded at the same portion. Thus, the conductive member 22 and the negative electrode tab group 14d can be electrically connected easily. The same applies to the connection between the conductive member 21 and the positive electrode tab group 13d.

  (3) In particular, in this embodiment, since the tip of the negative electrode tab 14c arranged in a shifted manner is laser-welded, compared to the case where all the negative electrode tabs 14c are repeatedly laser-welded at the same portion, welding is performed. It is possible to suppress the increase in the intensity of the required laser beam 71 and to electrically connect the conductive member 22 and the negative electrode tab group 14d easily. The same applies to the connection between the conductive member 21 and the positive electrode tab group 13d.

  (4) According to the manufacturing apparatus 30, since the negative electrode tab 14c of the stacked negative electrode 14 can be welded each time the negative electrode 14 is stacked, the negative electrode tab group 14d and the conductive member are formed while forming the electrode assembly 12. 22 can be electrically connected. For this reason, the conductive member 22 and the negative electrode tab group 14d can be easily combined with the conventional structure in which the negative electrode tab group 14d is further divided into a plurality of parts and welded to the conductive member 22 after the electrode assembly 12 is formed. Can be connected electrically. The same applies to the connection between the conductive member 21 and the positive electrode tab group 13d.

  (5) Then, according to the manufacturing apparatus 30, one apparatus includes an apparatus for stacking the electrodes 13 and 14 to form the electrode assembly 12, and an apparatus for welding the tab groups 13d and 14d to the current collecting member. It can be. Further, a device for dividing the tab groups 13d and 14d is not necessary. Therefore, an area required for installing the manufacturing apparatus for the secondary battery 10 can be reduced.

The embodiment is not limited to the above, and may be changed to another embodiment as follows, for example.
As shown in FIGS. 11 (a) and 11 (b) and FIGS. 12 (a) and 12 (b), the direction of the tip of the negative electrode tab 14c toward the tip of the negative electrode tab 14c every time one layer of the negative electrode 14 is stacked. The tip of the negative electrode tab 14c may be welded while being shifted in order in the (projection direction D1). In this case, the newly formed welded portion 14e is sequentially shifted toward the tip end side of the negative electrode tab 14c. Further, the negative electrode tab 14 c is gathered together on the end surface side opposite to the end surface 12 b of the electrode assembly 12. The connection between the conductive member 21 and the positive electrode tab group 13d can be similarly changed. Even if comprised in this way, the electrically-conductive member 22 and the negative electrode tab group 14d can be electrically connected simply.

  Further, as shown in FIGS. 11A and 11B and FIGS. 12A and 12B, the welding apparatus 70 may be a resistance welder (spot welder). In this case, each time one layer of the negative electrode 14 is overlapped, the tip of the negative electrode tab 14 c of the newly stacked negative electrode 14 and the conductive member 22 are sandwiched between the pair of welding electrode rods 72, and the welding electrode rod It is good to energize between 72. The laminated table 33 may be provided with a welding hole 33 c for inserting the welding electrode rod 72 into contact with the conductive member 22. The connection between the conductive member 21 and the positive electrode tab group 13d can be similarly changed. According to this configuration, since the current flowing between the welding electrode rods 72 can be reduced, consumption of the welding electrode rods 72 can be suppressed. Accordingly, the running cost can be reduced as the life of the welding electrode rod 72 can be extended.

  (Circle) about the said embodiment, the ultrasonic welding machine may be sufficient as the welding apparatus 70. FIG. Even if it is such a structure, the energy required for one welding can be reduced and the lifetime of the welding jig (horn) of an ultrasonic welding machine can be extended.

  In the above embodiment, in the forming step, the negative electrode tab 14c may be welded each time a plurality of layers of the negative electrode 14 are stacked. That is, the control device 80 controls the welding device 70 so that the negative electrode 14 is welded each time a plurality of layers are stacked, and the negative electrode tab 14c (negative electrode tab group 14d) is welded by a plurality of times of welding. The connection between the conductive member 21 and the positive electrode tab group 13d can be similarly changed.

  ○ In the forming step, every time a plurality of layers of the negative electrode 14 are stacked, the tip of the negative electrode tab 14c may be shifted in the direction toward the tip of the negative electrode tab 14c, and conversely, the tip is shifted in the direction toward the base end. May be. It can change similarly about the positive electrode tab group 13d.

In the forming step, the tip of the negative electrode tab 14c may be shifted in order in the width direction D2 each time one layer of the negative electrode 14 is stacked or each time a plurality of layers of the negative electrode 14 are stacked.
In the forming step, the tip of the negative electrode tab 14c may be welded by moving the lamination table 33 while fixing the irradiation position of the laser beam 71, that is, the position to be welded by the welding device 70.

  (Circle) the front-end | tip of the negative electrode tab 14c may be sequentially shifted to a predetermined direction by laminating | stacking the negative electrode 14 from which the length of the negative electrode tab 14c along the protrusion direction D1 differs. It can change similarly about the positive electrode tab group 13d.

  Only one of the negative electrode tab group 14d and the positive electrode tab group 13d may be welded each time one electrode is stacked or each electrode is stacked, and the other may be collectively welded.

The electrode assembly 12 may be a wound electrode assembly obtained by winding a belt-like positive electrode 13 and a belt-like negative electrode 14.
The negative electrode 14 may have the active material layer 14b only on one side. The positive electrode 13 can be similarly changed.

The negative electrode tab 14c may be provided by bonding another metal foil to the metal foil 14a. It can change similarly about the positive electrode tab 13c.
The secondary battery 10 is not limited to a lithium ion secondary battery, and may be another secondary battery such as a nickel hydrogen secondary battery or a nickel cadmium secondary battery.

O Not only the secondary battery 10, but also a power storage device such as an electric double layer capacitor or a lithium ion capacitor may be used.
The technical idea that can be grasped from the above embodiment will be added below.

  (A) Each time the electrode is stacked one layer or each time the electrode is stacked a plurality of layers, the tip of the current collector is shifted in the direction toward the tip of the current collector and the tip of the current collector It is preferable to weld the part.

  DESCRIPTION OF SYMBOLS 10 ... Secondary battery (electric storage apparatus), 12 ... Electrode assembly, 12a ... Edge, 13 ... Positive electrode (electrode), 13c ... Positive electrode tab (current collection part), 13d ... Positive electrode tab group (current collection part group) , 14 ... negative electrode (electrode), 14c ... negative electrode tab (current collector), 14d ... negative electrode tab group (current collector part), 21, 22 ... conductive member, 30 ... manufacturing device, 60 ... forming device, 70 ... Welding equipment.

Claims (4)

An electrode assembly having electrodes stacked in layers, and a conductive member, wherein the electrode assembly has a current collecting portion group in which current collecting portions of the electrodes are layered and projecting from an edge And the conductive member and the current collecting unit group are electrically connected power storage device manufacturing method,
A method of manufacturing a power storage device, comprising: welding a current collecting portion of the stacked electrodes each time one layer of the electrodes is stacked or each time a plurality of layers of the electrodes are stacked.   The electrode according to claim 1, wherein each time the electrode is stacked one layer or each time the electrode is stacked a plurality of layers, the tip of the current collector is sequentially shifted in a predetermined direction and the tip of the current collector is welded. A method for manufacturing a power storage device.   Each time the electrode is stacked one layer or each time the electrode is stacked a plurality of layers, the tip of the current collector is sequentially shifted in the direction toward the base of the current collector and the tip of the current collector is The manufacturing method of the electrical storage apparatus of Claim 1 or 2 which carries out laser welding. An electrode assembly having electrodes stacked in layers, and a conductive member, wherein the electrode assembly has a current collecting portion group in which current collecting portions of the electrodes are layered and projecting from an edge The conductive member and the current collecting unit group are electrically connected storage device manufacturing apparatuses,
A forming apparatus for stacking the electrodes in layers to form an electrode assembly;
And a welding device that welds a current collector of the stacked electrodes each time one layer of the electrodes is stacked by the forming device or each time a plurality of layers of the electrodes are stacked. Equipment manufacturing equipment.