JP2018129280A - Secondary battery and method of manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a secondary battery having a configuration that allows a collector terminal to be installed on an electrode body easily and joined to the electrode body easily and stably.SOLUTION: A secondary battery includes: an electrode body 30 including an electrode body portion 31, a collector foil protrusion portion 32, and a collector foil connection portion 33; a first collector terminal 10 including an extension portion 11 that is welded to the collector foil connection portion 33; and a second collector terminal 20 that is a member separate from the first collector terminal 10 and includes an extension portion 21 welded to the collector foil connection portion 33. The extension portions 11, 21 are located on the opposite sides of the collector foil connection portion 33. A welded portion where the extension portions 11, 21 and the collector foil connection portion 33 are united is formed by welding both the extension portions 11, 21 to the collector foil connection portion 33. The first collector terminal 10 and the second collector terminal 20 are united through the welded portion.SELECTED DRAWING: Figure 6

Description

  The present disclosure relates to a secondary battery and a manufacturing method thereof.

  In the secondary battery, an electrode body is configured by laminating or winding a plurality of electrode foils in order to realize high-efficiency discharge and high capacity. The electrode body is housed inside the case body together with a current collecting terminal (also referred to as a current collector), and the external terminal is disposed outside the case body (on the lid). The current collecting terminal attached to the electrode body electrically connects the electrode body and the external terminal.

  As disclosed in Japanese Patent Laid-Open No. 10-106536 (Patent Document 1), the ends of a plurality of current collecting foils constituting an electrode body are bundled inside slits provided in current collecting terminals. The two are welded together by laser welding. A similar technique is also disclosed in JP2013-179015A (Patent Document 2).

Japanese Patent Laid-Open No. 10-106536 JP 2013-179015 A

  A current collector terminal used in a conventional secondary battery and its manufacturing method has a plurality of extending portions, and a slit is formed between two adjacent extending portions (see Patent Documents 1 and 2). ).

  However, when inserting the ends of a plurality of current collector foils into the slit in a bundled state, if the slit width is narrow, it is difficult to insert the ends of the plurality of current collector foils into the slits. It may be difficult to assemble to the body. On the other hand, when joining the current collecting terminals by laser welding in a state where the ends of the current collecting foils are bundled, if the slit width is wide, that is, if the interval between the two extending portions is wide, It is difficult to bring the end of the current collector foil and the extended portion of the current collector terminal into contact with each other, or the current collector foil or separator is positioned inside the current collector terminal through the slit of the welding laser (So-called laser dropout) may result, making it difficult to perform appropriate welding.

  The present disclosure relates to a secondary battery having a configuration in which a current collecting terminal can be easily assembled to an electrode body, and the current collecting terminal can be easily and stably joined to the electrode body, and a method for manufacturing the secondary battery. The purpose is to provide.

  The secondary battery according to the present disclosure includes an electrode body portion in which current collector foils for a positive electrode and a negative electrode are laminated via a separator, and the current collector foils for the positive electrode and the negative electrode are respectively connected to the electrode body portion. A current collector foil extension formed on the outside of the current collector foil, and a plurality of the current collector foils constituting the current collector foil extension formed at the outer tip of the current collector foil extension. An electrode body including a current collector foil connection portion; and a first extension portion having a shape extending along a longitudinal direction of the current collector foil connection portion, wherein the first extension portion is the current collector foil connection portion. The first current collecting terminal welded to the first current collecting terminal and the second extending portion having a shape extending along the longitudinal direction, and the second extending portion is welded to the current collecting foil connecting portion. A current collecting terminal and a second current collecting terminal that is a separate member, and the first extending portion and the second extending portion are connected to the current collecting foil. Are located on opposite sides of each other, and both the first extension portion and the second extension portion are welded to the current collector foil connection portion, whereby the first extension portion and the second extension portion A welded portion that integrates the current portion and the current collector foil connection portion is formed, and the first current collector terminal and the second current collector terminal are integrated via the weld portion.

  In the secondary battery configured as described above, since the first current collecting terminal and the second current collecting terminal are configured as separate members, the first current collecting terminal and the second current collecting terminal in the manufacturing process thereof. Can be moved relative to each other to change the width of the slit, which is the portion into which the current collector foil connection portion is inserted. For example, when the current collector foil connection portion is inserted into the slit, the current collector foil connection portion is arranged with the first current collector terminal and the second current collector terminal arranged so that the slit width is maximized within the movable range. Can be inserted into the slit, and the first current collecting terminal and the second current collecting terminal can be easily assembled to the electrode body. Further, when laser welding is performed, the first current collecting terminal and the second current collecting terminal can be arranged so that the slit width becomes narrow, so that the current collecting foil connecting portion, the first current collecting terminal and the second current collecting terminal are arranged. The electrical terminals can be easily brought into contact with each other, and even if laser welding is performed, so-called laser missing does not occur, appropriate welding can be performed, and a high-quality secondary battery can be obtained. it can.

  In the above configuration, the first current collecting terminals are formed so as to be adjacent to each other with a gap therebetween, and the current collector foil connection portion is disposed so as to pass through the gap from the inside toward the outside. One first extending portion and a second first extending portion, wherein the first extending portion includes a flat plate portion extending along the longitudinal direction, and the flat plate portion. A convex portion having a shape projecting outward from an end portion on the side where the current collector foil connection portion is disposed, and the second extending portion of the second current collecting terminal is the second It arrange | positions so that the outer surface of a 1st extension part may overlap, and the said welding part is the edge part by which the said current collection foil connection part is located among the said 2nd extension parts, and the said current collection foil connection part And the said convex part provided in the 1st said 1st extension part may be integrated.

  According to said structure, compared with the case where a 2nd extension part is arrange | positioned between a 1st 1st extension part and a 2nd 1st extension part, a 1st 1st extension part Between the first and second extending portions can be reduced, the first current collecting terminal and the second current collecting terminal can be reduced in size, and the entire secondary battery can be obtained. It is also possible to achieve downsizing.

  Said structure WHEREIN: The said edge part by which the said current collection foil connection part is located among the said 2nd extension parts, and the said convex part provided in the said 1st 1st extension part are respectively The outer surface of each may have a substantially flush relationship.

  According to said structure, since a 1st current collection terminal and a 2nd current collection terminal are contacted or press-contacted equally from both sides with respect to the current collection foil connection part at the time of welding, a current collection foil connection part curves or The first current collecting terminal and the second current collecting terminal can be stably and easily welded to the current collector foil connecting portion without being bent.

  Said structure WHEREIN: The said welding part is a part other than the both ends in the said longitudinal direction among the said convex parts, the said current collection foil connection part, and the said current collection foil connection part of the said 2nd extension part. You may be provided so that the said edge part of the position side may be welded.

  With regard to the above configuration, in the process of welding, the current collector foil connection part to be welded changes from solid to liquid and returns to the solid again, so the current collector foil connection part is inserted. The width of the gap, which is a part, also changes during the welding process. According to said structure, the variation | change_quantity of the width | variety of a clearance gap can be made small and it becomes possible to reduce the influence which acts on the state of the welding part after welding. In addition, since the separator existing near the welded portion is vulnerable to heat, it is possible to reduce the thermal effect on the separator by shortening the weld length of the welded portion.

  A manufacturing method of a secondary battery based on the present disclosure includes an electrode main body portion in which current collector foils for positive electrodes and negative electrodes are laminated via a separator, and the current collector foils for positive electrodes and negative electrodes are respectively the electrode main bodies. Current collector foil extending part extending to the outside of the current collector, and a plurality of the current collector foils constituting the current collector foil extending part at the outer tip of the current collector foil extending part A step of preparing an electrode body including a formed current collector foil connection portion; and a shape including a first extension portion, wherein the first extension portion extends along a longitudinal direction of the current collector foil connection portion. A first current collecting terminal having a second extending portion, and the second extending portion has a shape extending along the longitudinal direction. The second current collecting terminal is a separate member from the first current collecting terminal. A step of preparing a terminal, and the first extending portion and the second extending portion are opposite to each other with respect to the current collector foil connecting portion. The first current collector terminal and the second current collector terminal are disposed so that the first extension part and the second extension part are close to each other. A step of bringing both the first extension part and the second extension part into contact with the current collector foil connection part by relatively moving the terminal and the second current collection terminal; and the first extension part In addition, laser welding is performed in a state where both of the second extension portions are in contact with the current collector foil connection portion, and the first extension portion, the second extension portion, and the current collector foil connection portion are A welding step of integrating the first current collecting terminal and the second current collecting terminal via the welded portion by forming a welded portion to be integrated.

  According to said structure, since the 1st current collection terminal and the 2nd current collection terminal are comprised as a mutually different member, the 1st current collection terminal and the 2nd current collection terminal are relatively moved in the manufacture process. By this, the width | variety of the slit which is a part into which a current collection foil connection part is inserted can be changed. For example, when the current collector foil connection portion is inserted into the slit, the current collector foil connection portion is arranged with the first current collector terminal and the second current collector terminal arranged so that the slit width is maximized within the movable range. Can be inserted into the slit, and the first current collecting terminal and the second current collecting terminal can be easily assembled to the electrode body. Further, when laser welding is performed, the first current collecting terminal and the second current collecting terminal can be arranged so that the slit width becomes narrow, so that the current collecting foil connecting portion, the first current collecting terminal and the second current collecting terminal are arranged. The electrical terminals can be easily brought into contact with each other, and even if laser welding is performed, so-called laser dropout does not occur, appropriate welding can be performed, and a high-quality secondary battery is produced. Is possible.

  In the above configuration, the first current collecting terminals are formed so as to be adjacent to each other with a gap therebetween, and the current collector foil connection portion is disposed so as to pass through the gap from the inside toward the outside. One first extending portion and a second first extending portion, wherein the first extending portion includes a flat plate portion extending along the longitudinal direction, and the flat plate portion. A convex portion having a shape protruding outward from an end portion on the side where the current collector foil connection portion is arranged, and the arranging step includes the second extending portion of the second current collecting terminal. The step of forming a slit between the second extending portion and the convex portion by disposing the second extending portion so as to overlap the outer surface of the first extending portion; Arranging the first current collecting terminal and the second current collecting terminal so as to pass through the slit from the inside toward the outside; And in the welding step, both of the end portion of the second extending portion on the side where the current collector foil connecting portion is located and the convex portion provided on the first extending portion. The laser welding is performed in a state where the current collector foil contact portion is in contact with the current collector foil connection portion, and the end of the second extension portion on the side where the current collector foil connection portion is located by forming the weld portion. Part, the said current collector foil connection part, and the said convex part provided in the 1st said 1st extension part may be integrated.

  According to said structure, compared with the case where a 2nd extension part is arrange | positioned between a 1st 1st extension part and a 2nd 1st extension part, a 1st 1st extension part Between the first and second extending portions can be reduced, the first current collecting terminal and the second current collecting terminal can be reduced in size, and the entire secondary battery can be obtained. It is also possible to achieve downsizing.

  In said structure, when the said laser welding is implemented, it provides in the said edge part of the side in which the said collector foil connection part is located among the said 2nd extension parts, and the said 1st said 1st extension part. The above-mentioned convex part has a relationship in which each outer surface is substantially flush.

  According to said structure, since a 1st current collection terminal and a 2nd current collection terminal are contacted or press-contacted equally from both sides with respect to the current collection foil connection part at the time of welding, a current collection foil connection part curves or The first current collecting terminal and the second current collecting terminal can be stably and easily welded to the current collector foil connecting portion without being bent.

  Said structure WHEREIN: The said welding part is a part other than the both ends in the said longitudinal direction among the said convex parts, the said current collection foil connection part, and the said current collection foil connection part of the said 2nd extension part. You may be provided so that the said edge part of the position side may be welded.

  With regard to the above configuration, in the process of welding, the current collector foil connection part to be welded changes from solid to liquid and returns to the solid again, so the current collector foil connection part is inserted. The width of the gap, which is a part, also changes during the welding process. According to said structure, the variation | change_quantity of the width | variety of a clearance gap can be made small and it becomes possible to reduce the influence which acts on the state of the welding part after welding. In addition, since the separator existing near the welded portion is vulnerable to heat, it is possible to reduce the thermal effect on the separator by shortening the weld length of the welded portion.

  According to the present disclosure, a secondary battery having a configuration in which the current collector terminal can be easily assembled to the electrode body and the current collector terminal can be easily and stably joined to the electrode body, and the manufacture thereof You can get the method.

4 is a cross-sectional view showing secondary battery 100 in the first embodiment. FIG. 3 is a perspective view showing an electrode body 30, a first current collecting terminal 10, and a second current collecting terminal 20 provided in the secondary battery 100 according to Embodiment 1. FIG. It is a figure (side view) which shows a mode when the 1st current collection terminal 10, the 2nd current collection terminal 20, etc. are seen along the arrow III line in FIG. It is a figure (plan view) which shows a mode when the 1st current collection terminal 10, the 2nd current collection terminal 20, etc. are seen along arrow IV line in FIG. It is arrow sectional drawing along the VV line in FIG. FIG. 3 is a perspective view showing an exploded state of the first current collecting terminal 10 and the second current collecting terminal 20 provided in the secondary battery 100 in the first embodiment. 3 is a diagram for illustrating a preparation process of a method for manufacturing secondary battery 100 in the first embodiment. FIG. 3 is a diagram for illustrating an arrangement process (first stage) of the method for manufacturing secondary battery 100 in the first embodiment. FIG. FIG. 6 is a diagram for explaining an arrangement step (second stage) of the method for manufacturing secondary battery 100 in the first embodiment. FIG. 4 is a diagram for explaining an arrangement process (third stage) of the method for manufacturing secondary battery 100 in the first embodiment. 3 is a diagram for illustrating a welding process of the method for manufacturing secondary battery 100 in the first embodiment. FIG. It is a perspective view which shows the secondary battery in a comparative example, and the current collection terminal 50 used for the manufacturing method. It is a figure for demonstrating the arrangement | positioning process of the manufacturing method of the secondary battery in a comparative example. It is a figure for demonstrating the welding process of the manufacturing method of the secondary battery in a comparative example. It is a figure for demonstrating the experiment regarding the comparative examples 1 and 2 based on a comparative example, and the Example based on Embodiment 1, and its result. 10 is a cross-sectional view for illustrating the method for manufacturing the secondary battery in the second embodiment. FIG. It is a perspective view which shows the 1st current collection terminal 10 and 2nd current collection terminal 20A used for the secondary battery in Embodiment 3, and its manufacturing method. It is sectional drawing which shows the 1st current collection terminal 10 and 20A of 2nd current collection terminals used for the secondary battery in Embodiment 3, and its manufacturing method. It is a perspective view which shows the 1st current collection terminal 10B and the 2nd current collection terminal 20B used for the secondary battery in Embodiment 4, and its manufacturing method. It is sectional drawing which shows the 1st current collection terminal 10B and the 2nd current collection terminal 20B which are used for the secondary battery in Embodiment 4, and its manufacturing method.

  Hereinafter, embodiments will be described with reference to the drawings. The same parts and corresponding parts are denoted by the same reference numerals, and redundant description may not be repeated.

[Embodiment 1]
(Secondary battery 100)
FIG. 1 is a cross-sectional view showing secondary battery 100 in the first embodiment. Secondary battery 100 is a non-aqueous electrolyte secondary battery, and can be used as, for example, a lithium ion battery. The secondary battery 100 is used to drive a vehicle, for example, and is a hybrid vehicle that uses an internal combustion engine such as a gasoline engine or a diesel engine and a motor powered by a chargeable / dischargeable battery as a power source, or external charging. It will be installed in plug-in hybrid vehicles and electric vehicles.

  The secondary battery 100 includes an electrode body 30, a case body 40, a positive electrode external terminal 37P, a negative electrode external terminal 37N, positive electrode current collector terminals 10P and 20P, and negative electrode current collector terminals 10N and 20N. Hereinafter, when there is no particular distinction between the positive electrode external terminal 37P and the negative electrode external terminal 37N (in other words, the same applies to the configuration common to these terminals), the positive electrode external terminal 37P is simply expressed as “external terminal 37”. When the electrical terminal 10P and the negative current collecting terminal 10N are not particularly distinguished, they are simply expressed as “first current collecting terminal 10”, and when the positive current collecting terminal 20P and the negative current collecting terminal 20N are not particularly distinguished. It is simply expressed as “second current collecting terminal 20”.

(Case body 40)
The case body 40 includes a main body portion 41 and a lid portion 42, and configures the appearance of the secondary battery 100. The main body 41 and the lid 42 are made of a metal such as aluminum. The main body 41 has a bottomed rectangular tube shape, and the lid 42 is provided so as to close the opening of the main body 41. External terminals 37 (positive electrode external terminal 37P and negative electrode external terminal 37N) are attached to the lid portion 42.

(Electrode body 30)
FIG. 2 is a perspective view showing the electrode body 30, the first current collecting terminal 10, and the second current collecting terminal 20 provided in the secondary battery 100. FIG. 3 is a diagram (side view) showing a state when the first current collecting terminal 10 and the second current collecting terminal 20 are viewed along the arrow III line in FIG. 2, and FIG. FIG. 5 is a diagram (plan view) illustrating a state when the first current collecting terminal 10 and the second current collecting terminal 20 are viewed along the arrow IV line in FIG. 5, and FIG. 5 is a view taken along the line VV in FIG. FIG. FIG. 6 is a perspective view showing the disassembled state of the first current collecting terminal 10 and the second current collecting terminal 20.

  2-6, the electrode body 30 is accommodated in the case body 40 (refer also FIG. 1). The electrode body 30 is composed of a laminate of a plurality of positive electrode current collector foils 31P, a plurality of separators 31S, and a plurality of negative electrode current collector foils 31N. The electrode body 30 may be composed of these wound bodies. The positive electrode current collector foil 31P is formed of, for example, an aluminum foil, and a paste containing a positive electrode active material is applied to both surfaces of the positive electrode current collector foil 31P. The negative electrode current collector foil 31N is formed of, for example, a copper foil, and a paste containing a negative electrode active material is applied to both surfaces of the negative electrode current collector foil 31N.

  The separator 31S has a substantially rectangular shape and is composed of a porous polypropylene resin sheet or the like. A region of the positive electrode current collector foil 31P coated with the positive electrode active material and a region of the negative electrode current collector foil 31N coated with the negative electrode active material face each other via the separator 31S. The region where the positive electrode active material of the positive electrode current collector foil 31P is not applied is exposed from one end in the longitudinal direction of the separator 31S, and the negative electrode active material of the negative electrode current collector foil 31N is applied. The region that is not exposed is exposed from the other end of the separator 31S in the longitudinal direction.

  The electrode body 30 is configured by laminating a plurality of positive electrode current collector foils 31P, a plurality of separators 31S, and a plurality of negative electrode current collector foils 31N as described above. The electrode body 30 configured in this manner (see FIG. 1) includes, as its constituent parts, an electrode main body 31, a positive current collector foil extension 32P, and a negative current collector extension 32N. Hereinafter, when the current collector foil extending portion 32P for the positive electrode and the current collector foil extending portion 32N for the negative electrode are not particularly distinguished, they are simply expressed as the “current collector foil extending portion 32”.

  The electrode main body 31 is a part where a positive electrode current collector foil 31P and a negative electrode current collector foil 31N are laminated via a separator 31S. The positive electrode current collector foil extension portion 32P is a portion where the positive electrode current collector foil 31P extends from the electrode main body portion 31 to one side, and the negative electrode current collector foil extension portion 32N is a negative electrode current collector foil 32N. This is a portion where the foil 31N extends from the electrode body 31 to the other side (FIG. 1). The positive electrode current collector foil extension portion 32 </ b> P and the negative electrode current collector foil extension portion 32 </ b> N extend to both outer sides of the electrode main body portion 31. The positive electrode current collector foil extending portion 32P and the negative electrode current collector foil extending portion 32N may be configured to extend only on one side (one side) of the electrode main body portion 31. Good.

  In the positive electrode current collector foil extending portion 32 </ b> P, a plurality of positive electrode current collector foils 31 </ b> P are stacked in the thickness direction of the electrode body 30. The plurality of positive electrode current collector foils 31P constituting the positive electrode current collector foil extension portion 32P are gathered together so that the positive electrode current collector foil extension portion 32P has a positive electrode A current collector foil connecting portion 33P is formed.

  In the negative electrode current collector foil extending portion 32 </ b> N, a plurality of negative electrode current collector foils 31 </ b> N are stacked in the thickness direction of the electrode body 30. The plurality of negative electrode current collector foils 31N constituting the negative electrode current collector foil extension part 32N are gathered together so that the negative electrode current collector foil extension part 32N has a negative electrode A current collector foil connecting portion 33N is formed. Hereinafter, when the current collector foil connecting portion 33P for positive electrode and the current collector foil connecting portion 33N for negative electrode are not particularly distinguished, they are simply expressed as “current collector foil connecting portion 33” (see FIGS. 2 to 6).

(First current collecting terminal 10 and second current collecting terminal 20)
As shown in FIG. 6, the external terminal 37 is disposed outside the case body 40 (FIG. 1) and is superimposed on the outer surface (upper surface) of the lid portion 42 via the insulator 36. The 1st current collection terminal 10 and the 2nd current collection terminal 20 are arranged in case body 40 (Drawing 1), and connect electrode body 30 and external terminal 37 electrically.

  Specifically, the positive current collecting terminals 10P and 20P electrically connect the positive external terminal 37P (FIG. 1) and the positive current collecting foil extending portion 32P (positive current collecting foil connecting portion 33P). Connecting. The positive electrode current collector terminals 10P, 20P are formed of the same type of metal (for example, aluminum, pure aluminum, or aluminum alloy) as the metal forming the positive electrode current collector foil 31P.

  The negative electrode current collector terminals 10N and 20N electrically connect the negative electrode external terminal 37N (FIG. 1) and the negative electrode current collector foil extending portion 32N (negative electrode current collector foil connecting portion 33N). The negative electrode current collector terminals 10N and 20N are formed of the same type of metal (for example, copper, pure copper, copper alloy) as the metal forming the negative electrode current collector foil 31N.

  The first current collecting terminal 10 is superimposed on the inner surface (lower surface) of the lid portion 42 via the insulator 35. It is electrically connected to the external terminal 37 through the conductive pin member 34. The first current collecting terminal 10 and the pin member 34 may be integrally molded. The 1st current collection terminal 10 has the base 16 and the extension parts 11-14 as the structure part. The base portion 16 has a portion formed in a flat plate shape, and is overlapped on the inner surface of the lid portion 42 via the insulator 35.

  The extending parts 11 to 14 extend in a direction away from the base part 16. Each of the extending portions 11 to 14 has a shape extending in parallel along the longitudinal direction of the current collector foil connecting portion 33, and a slit S <b> 1 (FIG. 8) is formed between the extending portions 11 to 14. . The extending portions 11 to 14 are formed so as to be adjacent to each other with a slit S1 (gap) therebetween, and are disposed so as to pass through the slit S1 (gap) from the inside toward the outside. (Fig. 5).

  Each of the extending portions 11 to 14 includes a flat plate portion 17 extending along the longitudinal direction of the current collector foil connecting portion 33 and an end portion 19 on the side where the current collector foil connecting portion 33 of the flat plate portion 17 is disposed ( 5 and 8) and a convex portion 18 having a shape protruding outward (FIGS. 3 and 4). The outer surface 18S of the convex portion 18 (a region where the weld 38 is not formed) has a flat planar shape (see FIG. 8). In a state before the current collector foil connecting portion 33 is welded to the extending portions 11 to 14, the end surface located on the end portion 19 side of the flat plate portion 17 and the end portion 19 side of the convex portion 18 are located. The end surface is smoothly continuous so as to form a single plane, and is parallel to the extending direction of the current collector foil connecting portion 33 (vertical direction in the plane of FIG. 5) (see FIG. 8).

  The 2nd current collection terminal 20 is a member mutually different from the 1st current collection terminal 10, and the 2nd current collection terminal 20 has base 26 and extension parts 21-24 as the component. The base portion 26 has a portion formed in a flat plate shape and is superimposed on the upper surface of the base portion 16. The extending portions 21 to 24 extend in a direction away from the base portion 26. Each of the extending portions 21 to 24 has a shape extending along the longitudinal direction of the current collector foil connecting portion 33, and the outer surface 28 of the extending portions 21 to 24 (region where the welded portion 38 is not formed) And has a flat planar shape (see FIG. 8).

  A slit S2 (FIG. 8) is formed between the extending portions 21 to 24. The extending portions 21 to 24 are formed so as to be adjacent to each other with the slit S2 (gap) therebetween, and are disposed so as to pass through the slit S2 (gap) from the inside toward the outside. (Fig. 5). In the state before the current collector foil connection portion 33 is welded to the extension portions 21 to 24, the end portion 29 on the side where the current collector foil connection portion 33 of each of the extension portions 21 to 24 is located, It is parallel to the extending direction of the current collector foil connecting portion 33 (vertical direction in FIG. 5) (see FIG. 8).

  Here, the extending portion 11 (first extending portion) of the first current collecting terminal 10 and the extending portion 21 (second extending portion) of the second current collecting terminal 20 are connected to one current collector foil. They are located on opposite sides of the portion 33 (with respect to one current collector foil connecting portion 33) (FIG. 5). Both the extension part 11 and the extension part 21 are welded to the current collector foil connection part 33 located between them, so that the extension part 11, the extension part 21, and the current collector located between these parts are welded. A welded portion 38 that integrates the electric foil connecting portion 33 is formed. The first current collecting terminal 10 and the second current collecting terminal 20 are integrated through a welded portion 38.

  In the present embodiment, the first current collecting terminal 10 includes an extending portion 11 (first first extending portion) and an extending portion 12 (second first extending portion), The extension part 21 (second extension part) of the second current collecting terminal 20 is arranged so as to overlap the outer surface of the flat plate part 17 of the extension part 12 (second first extension part). The welded portion 38 is connected to the end portion 29 on the side where the current collector foil connecting portion 33 is located in the extending portion 21 (second extending portion) and the extending portion 11 (first first extending portion). The provided convex part 18 and the current collector foil connection part 33 located between these are integrated.

  As shown in FIG. 5, the relationship between the extending portions 12 and 22 and the current collector foil connecting portion 33 positioned therebetween, and the relationship between the extending portions 13 and 23 and the current collector foil connecting portion 33 positioned therebetween. In addition, the relationship between the extending portions 14 and 24 and the current collector foil connecting portion 33 positioned therebetween is the same as the relationship between the extending portions 11 and 21 and the current collector foil connecting portion 33 positioned therebetween. It is the same. In the present embodiment, the first current collecting terminal 10 and the second current collecting terminal 20 are configured as separate members, and are integrated with each other via four welds 38.

(Production method)
Hereinafter, a method for manufacturing the secondary battery 100 will be described with reference to FIGS. Referring to FIG. 7, an electrode body 30 is first prepared. Specifically, a plurality of positive electrode current collector foils 31P, a plurality of separators 31S, and a plurality of negative electrode current collector foils 31N are stacked. Thereby, the electrode main body 31 in which the positive electrode current collector foil 31P and the negative electrode current collector foil 31N are laminated via the separator 31S, and the positive electrode current collector foil 31P and the negative electrode current collector foil 31N are respectively electrode main body portions. Current collector foil extension part 32 (positive electrode current collector foil extension part 32P and negative electrode current collector foil extension part 32N), which extends to both outer sides with respect to 31, a laminate (electrode body 30) ) Is obtained. In the laminate, both the current collector foil 31P for the positive electrode and the current collector foil 31N for the negative electrode are respectively extended to the outer side of the electrode main body portion 31 (current collector foil extension portion 32). The foil extending portion 32P and the negative electrode current collector foil extending portion 32N) may be included.

  Thereafter, the plurality of current collector foils (the positive electrode current collector foil 31P and the negative electrode current collector foil 31N) constituting the current collector foil extending portion 32 are converged by the jig 60 having an inclined surface. Collected. A current collector foil connection portion 33 (current collector for positive electrode) having a width W1 (FIG. 8) at the outer end of the current collector foil extension portion 32 by a plurality of current collector foils constituting the current collector foil extension portion 32. The foil connection part 33P and the negative electrode current collector foil connection part 33N) are formed. As described above, the electrode body 30 including the electrode main body 31, the current collector foil extension 32, and the current collector connection 33 is prepared.

  Referring to FIG. 8, next, a first current collecting terminal 10 and a second current collecting terminal 20 are prepared. As described above, the first current collecting terminal 10 includes the extending portions 11 to 14 formed so as to be adjacent to each other with a gap (slit S1) therebetween, and the extending portions 11 to 14 are the current collecting foil connecting portions. 33 has a shape extending along the longitudinal direction. Each of the extending portions 11 to 14 includes a flat plate portion 17 extending along the longitudinal direction of the current collector foil connecting portion 33 and an end portion 19 on the side where the current collector foil connecting portion 33 of the flat plate portion 17 is disposed ( 5 and 8) and a convex portion 18 having a shape protruding outward (FIGS. 3 and 4). The extension part 11 corresponds to a first first extension part, and the extension part 12 corresponds to a second first extension part.

  The second current collecting terminal 20 includes extending portions 21 to 24 formed so as to be adjacent to each other with a gap (slit S <b> 2) therebetween, and the extending portions 21 to 24 are also in the longitudinal direction of the current collector foil connecting portion 33. It has the shape extended along. The extending portion 21 corresponds to a second extending portion, and the second current collecting terminal 20 is a separate member from the first current collecting terminal 10 as described above. The first current collecting terminal 10 having such a configuration is formed by forming three slits (slits S1, S2) having a predetermined width in a metal plate material by laser processing, press processing, or the like, and then a portion corresponding to the base portion 16 is formed. It can be easily manufactured by bending the metal plate into an L shape.

(Arrangement process)
Thereafter, the second current collecting terminal 20 is superimposed on the outside of the first current collecting terminal 10. At this time, each convex portion 18 of the extending portions 12 to 14 is inserted into a slit S <b> 2 provided in the second current collecting terminal 20. The extension of the second current collecting terminal 20 between the protrusion 18 of the extension 11 (first first extension) and the protrusion 18 of the extension 12 (second first extension). The existing portion 21 (second extending portion) is arranged. The extension part 21 (second extension part) of the second current collecting terminal 20 is disposed so as to overlap the outer surface of the flat plate part 17 of the extension part 12 (second first extension part). The extending portions 21 to 23 of the second current collecting terminal 20 are arranged so as to overlap the outer surfaces of the extending portions 12 to 14 of the first current collecting terminal 10, respectively. A slit is formed between each of the convex portions 18 of the existing portions 11 to 14.

  Referring to FIG. 9, in the present embodiment, extension portion 21 (the first current collecting terminal 10 and the second current collecting terminal 20 are arranged so as to overlap each other as described above. End portion 29 on the side where the current collector foil connecting portion 33 is located, and the convex portion 18 provided in the extending portion 11 (first first extending portion) The outer surfaces 18S and 28 have a substantially flush relationship. The same applies to the extending portions 12 to 14 and the extending portions 22 to 24.

  As shown in FIGS. 9 and 10, the slits (the gap between the extending portions 11 to 14 (slit S1) and the gap between the extending portions 21 to 24 (slit S2)) are connected to the current collector foil connecting portion 33. Are arranged such that the first current collecting terminal 10 and the second current collecting terminal 20 pass from the inside toward the outside. By completing the arrangement process as described above, for example, the extending portion 11 (first extending portion) and the extending portion 21 (second extending portion) are mutually connected to one current collector foil connecting portion 33. The 1st current collection terminal 10 and the 2nd current collection terminal 20 are arranged so that it may be located on the opposite side (the state shown in Drawing 10 is obtained). The same applies to the extending portions 12 to 14 and the extending portions 22 to 24.

  Thereafter, the first current collecting terminal 10 and the second current collecting terminal 20 are relatively moved so that the extending portion 11 (first extending portion) and the extending portion 21 (second extending portion) are close to each other ( Here, it is slid). The same applies to the extending portions 12 to 14 and the extending portions 22 to 24. The width W2 (FIG. 9) is uniformly reduced in the longitudinal direction of the current collector foil connection portion 33, so that the extension portions 11 to 14 and the extension portions 21 to 24 are all located between them. The contact portion 33 can be evenly contacted.

(Welding process)
Referring to FIG. 11, the protruding portions 18 of the extending portions 11 to 14 and the end portion 29 on the side where the current collector foil connecting portion 33 of each of the extending portions 21 to 24 is located are Laser welding using the laser L is performed in a state where it is in contact with the current collector foil connecting portion 33 located between the two. At this time, in order to make the gap between the convex portion 18 and the end portion 29 constant (or less than a certain value), the first current collecting terminal 10 and the second current collecting terminal 20 are connected so that the gap becomes small. Laser welding is performed under pressure.

  When laser welding is performed, the outer surface 18S of the convex portion 18 and the outer surface 28 of each of the extending portions 21 to 24 have a substantially flush relationship. A welded portion 38 (FIG. 5) is formed to integrate each of the extending portions 11 to 14, each of the extending portions 21 to 24, and the current collector foil connecting portion 33 positioned therebetween. The 1st current collection terminal 10 and the 2nd current collection terminal 20 are integrated via welding part 38 (four welding parts 38 in this embodiment).

  In the present embodiment (see FIG. 3), the welded portion 38 includes a portion 18H other than both ends 18A and 18B in the longitudinal direction of the convex portion 18 of the extending portion 11 (first first extending portion). The current collector foil connecting portion 33 and the end portion 29 (FIG. 5) on the side where the current collector foil connecting portion 33 of the extending portion 21 (second extending portion) is positioned are welded. Yes. The same applies to the extending portions 12 to 14 and the extending portions 22 to 24.

  A pin member 34, an insulator 35, a lid 42, an insulator 36 and an external terminal 37 shown in FIG. 6 are assembled to the first current collecting terminal 10 integrated with the electrode body 30. The electrode body 30 integrated with the external terminal 37 and the lid portion 42 (FIG. 1) is accommodated in the main body portion 41 of the case body 40 (FIG. 1), and the lid portion 42 is welded to the main body portion 41. An electrolyte is injected into the case body 41 through a liquid injection hole provided in the lid portion 42, and then the liquid injection hole is closed. Through the above steps, the secondary battery 100 in FIG. 1 is completed.

(Function and effect)
Hereinafter, the operation and effect of the first embodiment will be described in comparison with the comparative examples shown in FIGS.

  In the case of the comparative example shown in FIG. 12, the current collecting terminal 50 has a base portion 56 and a plurality of extending portions 51 to 55, and a slit S3 (FIG. 13) is provided between two adjacent extending portions. It is formed. As shown in FIG. 13, when the current collector foil connecting portion 33 is inserted into the slit S3, if the width W3 of the slit S3 is narrow, it is difficult to insert the current collector foil connecting portion 33 into the slit S3. As a result, the current collecting terminal 50 Is difficult to assemble to the electrode body 30.

  Referring to FIG. 14, on the other hand, when the current collector foil connecting portion 33 is joined to the extending portions 51 to 55 of the current collecting terminal 50 by laser welding, if the slit S3 is wide, that is, two adjacent extensions. When the interval between the existing portions is wide, it becomes difficult to join the current collector foil connecting portion 33 and the extending portions 51 to 55 of the current collecting terminal 50 to each other. In this case, the welding laser L passes through the slit S3 and reaches the current collector foil or the separator located inside the current collector terminal (so-called laser missing), and as a result, it is difficult to perform appropriate welding. There is also a possibility of becoming.

  On the other hand, according to the secondary battery 100 in the present embodiment, the portion corresponding to the slit is constituted by the first current collecting terminal 10 and the second current collecting terminal 20 which are separate members. . According to the secondary battery 100 having such a configuration, when inserting the ends of the current collector foils (current collector foil connection portions 33) into a slit in a bundled state, the slit width is the largest in the movable range. With the first current collecting terminal 10 and the second current collecting terminal 20 disposed so as to be limited, the current collecting foil connecting portion 33 can be inserted into the slit, and the first current collecting terminal 10 and the second current collecting terminal can be inserted. The terminal 20 can be easily assembled to the electrode body 30.

  When joining the first current collecting terminal 10 and the second current collecting terminal 20 by laser welding in a state where the ends of the current collecting foils (current collecting foil connecting portions 33) are bundled, the slit width becomes narrow. The first current collecting terminal 10 and the second current collecting terminal 20 can be arranged as described above (for example, the first current collecting terminal 10 and / or the second current collecting terminal 20 can be slid and moved). The current collector foil connecting portion 33 and the extending portions 11 to 14 and 21 to 24 can be easily brought into contact with each other. Since the current collector foil connecting portion 33 and the extending portions 11 to 14 and 21 to 24 are in contact with each other, the welding laser passes through the slit and the first current collecting terminal 10 and the second current collecting terminal 20 are connected. Appropriate welding can be performed without causing a so-called laser drop-out that reaches the electrode body 30 (current collector foil) located on the inner side.

  In the present embodiment, the extending portions 21 to 23 of the second current collecting terminal 20 are arranged so as to overlap the outer surfaces of the extending portions 12 to 14 of the first current collecting terminal 10, respectively. The welded portion 38 is connected to the end portion 29 on the side where the current collector foil connecting portion 33 is located in the extending portion 21 (second extending portion) and the extending portion 11 (first first extending portion). The provided convex part 18 and the current collector foil connection part 33 located between these are integrated. The same applies to the extending portions 12 to 14 and the extending portions 22 to 24.

  In relation to the above configuration, the width of the slit S1 between the extending portions 11 to 14 is made wider than that in the first embodiment, and the extending portions 21 to 21 of the second current collecting terminal 20 are placed in the slit S1. 24 can also be arranged. In this case, the extending portions 11 to 14 and the extending portions 21 to 24 are alternately arranged in the thickness direction of the electrode body 30 (direction perpendicular to the paper surface of FIG. 1) on the same plane. Even in this case, it is possible to increase or decrease the width of the slit formed between the extending portions 11 to 14 and 21 to 24 by the relative movement of the first current collecting terminal 10 and the second current collecting terminal 20. Yes, substantially the same operations and effects as described above can be obtained.

  On the other hand, in the above-described first embodiment, the extending portions 21 to 23 of the second current collecting terminal 20 are arranged so as to overlap the outer surfaces of the extending portions 12 to 14 of the first current collecting terminal 10, respectively. The Although the said structure is not essential, when the said structure is employ | adopted, compared with the case where it is comprised so that the extension parts 11-14 and the extension parts 21-24 may be located in a line by turns, it is the extension part 11 , The width of the slit formed between the first current collecting terminal 10 and the second current collecting terminal 20 as a whole can be reduced. As a result, the secondary battery 100 can be made smaller. It becomes possible to achieve downsizing. Moreover, the welding part 38 has each edge part 29 of the extension parts 21-24, the convex part 18 provided in each of the extension parts 11-14, and the current collector foil connection part 33 located among these. Therefore, it is possible to perform necessary and sufficient welding.

  As described above, in the first embodiment, the end portion 29 on the side where the current collector foil connecting portion 33 is located in the extending portion 21 (second extending portion) and the extending portion 11 (first first portion). The projecting portion 18 provided in the (one extending portion) has a relationship in which the outer surfaces 18S and 28 are substantially flush with each other. The same applies to the extending portions 12 to 14 and the extending portions 22 to 24. Although the said structure is not essential, according to the said structure, each edge part 29 of the extension parts 21-24 and the convex part 18 provided in each of the extension parts 11-14 gather at the time of welding. Since the current collector foil connection portion 33 is uniformly contacted or pressed from both sides, the current collector foil connection portion 33 is not bent or bent, and the end portion 29 and the convex portion 18 are connected to the current collector foil connection. It becomes possible to stably and easily weld the portion 33.

  As described above, in the present embodiment (see FIG. 3), the welded portion 38 is other than both ends 18 </ b> A and 18 </ b> B in the longitudinal direction of the convex portion 18 of the extending portion 11 (first first extending portion). Part 18H, current collector foil connection portion 33, and end portion 29 (FIG. 5) on the side where current collector foil connection portion 33 of extension portion 21 (second extension portion) is located are welded. Is provided. The same applies to the extending portions 12 to 14 and the extending portions 22 to 24.

  In order to stably weld the extending portions 11 to 14, the extending portions 21 to 24, and the current collector foil connecting portion 33 between them, the extending portions 11 to 14 (implementation) In the first embodiment, the gap between the projecting portion 18) and the extending portions 21 to 24 (end portion 29) is made constant (or less than a certain value), and the first current collecting terminal 10 Laser welding is performed in a state where the second current collecting terminal 20 is pressurized. In the welding process, the current collector foil connection portion 33 to be welded changes from a solid to a liquid and then returns to the solid, so that the gap width also changes during the welding process. It becomes.

  Here, if it is going to weld all the area | regions where the current collection foil connection part 33 is pinched | interposed by the convex part 18 and the edge part 29, the volume of the welding object to fuse | melt will increase that much, and the variation | change_quantity of the width | variety of a gap | interval growing. Changing the gap width to increase and decrease again during the welding process also affects the state of the welded portion 38 after welding. Therefore, the gap width change amount is preferably as small as possible.

  Therefore, in the present embodiment, the welded portion 38 includes portions 18H other than both ends 18A and 18B in the longitudinal direction of the projecting portions 18 of the extending portions 11 to 14, the current collector foil connecting portion 33, and the extended portion. By being provided so as to weld the end portions 29 (FIG. 5) of the existing portions 21 to 24, it is possible to form a good and stable welded portion 38. Although the separator 31S present near the welded portion is vulnerable to heat, it is also possible to reduce the thermal effect on the separator 31S by shortening the weld length of the welded portion 38. Depending on the specifications of the secondary battery 100 and the like, the weld length of the weld 38 necessary for electrical connection can be determined. Therefore, it is preferable that the weld length of the welded portion 38 is set to a necessary and sufficient value (for example, 10 mm) including the portion 18H other than the both ends 18A and 18B in consideration of the specifications of the secondary battery 100 and the like.

[Experimental example]
With reference to FIG. 15, experiments and results regarding Comparative Examples 1 to 3 based on the above-described comparative example and Examples based on the above-described first embodiment will be described.

  As conditions common to Comparative Examples 1 to 3 and Examples, the thickness of the positive electrode current collector foil 31P (aluminum alloy foil) was set to 15 μm, and the thickness of the negative electrode current collector foil 31N (copper foil) was set to 10 μm. . The width W1 (FIG. 8) of the current collector foil connecting portion 33 was 0.5 mm. The positive electrode current collector terminal 10P, the positive electrode current collector terminal 20P, and the current collector terminal 50 on the positive electrode side were made of aluminum and had a thickness of 0.8 mm. The negative electrode current collector terminal 10N, the negative electrode current collector terminal 20N, and the current collector terminal 50 on the negative electrode side were made of copper and had a thickness of 0.8 mm.

  As welding conditions on the positive electrode side, a fiber laser having an output of 2000 W and a speed of 20 mm / SEC was used, and the scanning distance was set to 10 mm. As welding conditions on the negative electrode side, a fiber laser having an output of 3000 W and a speed of 30 mm / SEC was used, and the scanning distance was set to 10 mm. About the other, based on the conditions shown by FIG. 15, ten samples of the secondary battery were produced for each of Comparative Examples 1 to 3 and Examples. As an evaluation 1, the appearance of the state of being inserted into the slit of the current collector foil connecting portion 33 was observed, and as an evaluation 2, an appearance of the disassembled welded portion (welded portion 38) was observed.

(Comparative Example 1)
In Comparative Example 1, the width W3 of the slit S3 (FIG. 13) was set to 0.6 mm. Regarding evaluation 1, when the current collector foil connection portion 33 was inserted into the slit S3, the current collector foil connection portion 33 collided with the extending portions 51 to 55 constituting the slit S3 for the two samples, Since it was confirmed that damage (fracture of the foil) occurred in the electric foil connecting portion 33, a result of 8/10 was obtained for the evaluation 1. Regarding the evaluation 2, it is not confirmed that a laser drop occurs in the gap between the current collector foil connecting portion 33 and the extending portions 51 to 55, and a result of 8/8 is obtained for the evaluation 2. It was. From these results, it can be said that Comparative Example 1 may cause damage to the current collector foil connecting portion 33.

(Comparative Example 2)
In Comparative Example 2, the width S3 of the slit S3 (FIG. 13) was set to be 0.9 mm. Regarding evaluation 1, when the current collector foil connection portion 33 is inserted into the slit S3, the current collector foil connection portion 33 does not collide with the extending portions 51 to 55, and the current collector foil connection portion 33 is damaged (foil As a result, a result of 10/10 was obtained for evaluation 1. Regarding evaluation 2, since it was confirmed in four samples that laser dropout occurred in the gap between the current collector foil connecting portion 33 and the extending portions 51 to 55, the result of evaluation 2 was 6/10. was gotten. In Comparative Example 2, since the width W3 of the slit S3 is wider than that in Comparative Example 1, it is easy to insert the current collector foil connection portion 33. However, when the current collector foil connection portion 33 is sandwiched between the extending portions 51 to 55, It is inferred that laser dropout occurred frequently.

(Example)
In the embodiment, unlike the cases of Comparative Examples 1 and 2, the part functioning as the current collecting terminal is composed of two parts, the first current collecting terminal 10 and the second current collecting terminal 20 which are separate members. The As a result, good results of 10/10 were obtained in both evaluations 1 and 2. Therefore, according to the configuration based on the first embodiment, the secondary battery having a configuration in which the current collecting terminal can be easily assembled to the electrode body and the current collecting terminal can be easily joined to the electrode body, and It can be said that the manufacturing method is possible.

[Embodiment 2]
With reference to FIG. 16, the manufacturing method of the secondary battery in Embodiment 2 will be described. In the arrangement process in the first embodiment described above (FIGS. 8 to 10), the second current collecting terminal 20 is superimposed on the outside of the first current collecting terminal 10, and then the first current collecting terminal 10 and the second current collecting terminal are overlapped. The current collector foil connecting portion 33 is inserted inside a slit formed between the electric terminals 20.

  As shown in FIG. 16, as the arranging step, after the current collector foil connecting portion 33 is inserted into the slit S <b> 1 of the first current collector terminal 10, the second current collector terminal 20 is overlapped on the first current collector terminal 10. Also good. Also with this configuration, the same operations and effects as those of the first embodiment can be obtained.

[Embodiment 3]
With reference to FIG. 17 and FIG. 18, the secondary battery and the manufacturing method thereof in Embodiment 3 will be described. In the first embodiment, the second current collecting terminal 20 includes the base portion 26 (FIG. 6), and the extending portions 21 to 24 are formed to extend from the L-shaped base portion 26. 20 A of 2nd current collection terminals of this Embodiment are provided with the flat base part 27 and the extension parts 21-24 formed so that it might hang down from the base part 27. As shown in FIG.

  In the case of the first embodiment, it is possible to easily position the second current collecting terminal 20 with respect to the first current collecting terminal 10 using the base portion 26, but the second current collector as in the present embodiment is used. Even with the configuration of the electric terminal 20A, welding can be easily performed by appropriately providing a member for supporting or positioning the second current collecting terminal 20A at the time of welding. Similar actions and effects can be obtained.

[Embodiment 4]
With reference to FIG. 19 and FIG. 20, the secondary battery and the manufacturing method thereof in the fourth embodiment will be described. In this Embodiment, the flat plate part 17 which comprises the extension parts 11-13 of the 1st current collection terminal 10B is curving in the middle part in a longitudinal direction, and is on the upper end of the extension parts 11-13. Compared with the lower end, it has a configuration closer to the inside.

  Similarly, the extending portions 21 to 23 of the second current collecting terminal 20B are curved in the middle in the longitudinal direction, and the lower ends of the extending portions 21 to 23 (on the base 27 side). Compared to (part), the upper end is closer to the inside. Even when the welding location is arranged so as to be embedded inside the current collector foil connection portion 33, the same operation and effect as those of the first embodiment can be obtained.

  Although the embodiment has been described above, the above disclosure is illustrative in all respects and is not restrictive. The technical scope of the present disclosure is defined by the terms of the claims, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  10, 10B 1st current collection terminal, 10N, 10P, 20N, 20P, 50 Current collection terminal, 11, 12, 13, 14, 21, 22, 23, 24, 51, 55 Extension part, 16, 26, 27 , 56 Base part, 17 Flat part, 18 Convex part, 18A, 18B Both ends, 18H part, 18S, 28 Outer surface, 19, 29 End part, 20, 20A, 20B Second current collecting terminal, 30 Electrode body, 31 Electrode body Part, 31N negative electrode current collector foil, 31P positive electrode current collector foil, 31S separator, 32 current collector foil extension part, 32P positive electrode current collector foil extension part, 32N negative electrode current collector foil extension part, 33 current collector Foil connection part, 33N current collector foil connection part for negative electrode, 33P current collector foil connection part for positive electrode, 34 pin member, 35, 36 insulator, 37 external terminal, 37N external terminal for negative electrode, 37P external terminal for positive electrode, 38 welding Part, 40 cases S body, 41 body portion, 42 lid portion, 60 jig, 100 secondary battery, L laser, S1, S2, S3 slit, W1, W2, W3 width.

Claims (8)

A current collector foil in which positive and negative current collector foils are laminated via a separator, and a current collector foil in which positive current and negative current collector foils extend outward from the electrode main body, respectively. Including a current collector foil extending portion and a current collector foil connecting portion formed at the outer front end of the current collector foil extending portion by the plurality of current collector foils constituting the current collector foil extending portion, An electrode body;
A first current collecting terminal including a first extending portion having a shape extending along a longitudinal direction of the current collecting foil connecting portion, wherein the first extending portion is welded to the current collecting foil connecting portion;
A second extension part including a second extension part extending along the longitudinal direction, wherein the second extension part is welded to the current collector foil connection part and is a member separate from the first current collector terminal. A current collecting terminal,
The first extension part and the second extension part are located on opposite sides of the current collector foil connection part,
Both the first extension part and the second extension part are welded to the current collector foil connection part, so that the first extension part, the second extension part, and the current collector foil connection part are A welded part to be integrated is formed, and the first current collecting terminal and the second current collecting terminal are integrated via the welded part,
Secondary battery. The first current collecting terminals are formed so as to be adjacent to each other with a gap therebetween, and the current collector foil connection portion is disposed so as to pass through the gap from the inside toward the outside. An extension portion and a second first extension portion,
The first first extending portion has a flat plate portion extending along the longitudinal direction and a shape protruding outward from an end portion of the flat plate portion on the side where the current collector foil connecting portion is disposed. And a convex portion having
The second extending portion of the second current collecting terminal is disposed so as to overlap the outer surface of the second first extending portion,
The welded portion is provided at an end of the second extending portion on the side where the current collector foil connecting portion is located, the current collector foil connecting portion, and the first first extending portion. Integrating the convex part,
The secondary battery according to claim 1. Of the second extending portion, the end portion on the side where the current collector foil connecting portion is located, and the convex portion provided on the first extending portion of the first, each outer surface is substantially Have a flush relationship,
The secondary battery according to claim 2. The welded portion is a portion of the convex portion other than both ends in the longitudinal direction, the current collector foil connecting portion, and the side of the second extending portion where the current collector foil connecting portion is located. Provided to weld the end,
The secondary battery according to claim 2 or 3. A current collector foil in which positive and negative current collector foils are laminated via a separator, and a current collector foil in which positive current and negative current collector foils extend outward from the electrode main body, respectively. Including a current collector foil extending portion and a current collector foil connecting portion formed at the outer front end of the current collector foil extending portion by the plurality of current collector foils constituting the current collector foil extending portion, Preparing an electrode body;
1st extension part is included, the 1st extension part contains the 1st current collection terminal which has the shape extended along the longitudinal direction of the current collection foil connection part, and the 2nd extension part, and the 2nd extension Preparing a first current collecting terminal and a second current collecting terminal which are separate members from each other, wherein the existing part has a shape extending along the longitudinal direction;
Arrangement for disposing the first current collecting terminal and the second current collecting terminal so that the first extending portion and the second extending portion are located on opposite sides of the current collector foil connecting portion. Process,
By relatively moving the first current collecting terminal and the second current collecting terminal so that the first extending part and the second extending part are close to each other, the first extending part and the second extending part are moved. A step of bringing both the extending portions into contact with the current collector foil connecting portion;
Laser welding is performed in a state where both the first extension part and the second extension part are in contact with the current collector foil connection part, and the first extension part, the second extension part, and the A welding step of integrating the first current collecting terminal and the second current collecting terminal via the welded portion by forming a welded portion that integrates the current collector foil connecting portion,
A method for manufacturing a secondary battery. The first current collecting terminals are formed so as to be adjacent to each other with a gap therebetween, and the current collector foil connection portion is disposed so as to pass through the gap from the inside toward the outside. An extension portion and a second first extension portion,
The first first extending portion has a flat plate portion extending along the longitudinal direction and a shape protruding outward from an end portion of the flat plate portion on the side where the current collector foil connecting portion is disposed. And a convex portion having
The arrangement step includes
By arranging the second extending portion of the second current collecting terminal so as to overlap the outer surface of the second extending first portion, a slit is formed between the second extending portion and the convex portion. Forming a step;
Disposing the first current collector terminal and the second current collector terminal so that the current collector foil connection portion passes through the slit from the inside toward the outside,
In the welding step, both the end portion on the side where the current collector foil connection portion is located in the second extending portion and the convex portion provided on the first extending portion are both The laser welding is performed in a state where it is in contact with the current collector foil connection portion, and the end portion on the side where the current collector foil connection portion is located in the second extension portion by forming the weld portion; The current collector foil connecting portion and the convex portion provided on the first extending portion are integrated.
The method for manufacturing a secondary battery according to claim 5. When the laser welding is performed, the end portion on the side where the current collector foil connecting portion is located in the second extending portion, and the convex portion provided on the first extending portion. And each outer surface has a substantially flush relationship,
The manufacturing method of the secondary battery of Claim 6. The welded portion is a portion of the convex portion other than both ends in the longitudinal direction, the current collector foil connecting portion, and the side of the second extending portion where the current collector foil connecting portion is located. Provided to weld the end,
The manufacturing method of the secondary battery of Claim 6 or 7.

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