JP6885121B2 - Secondary battery and its manufacturing method - Google Patents

Description

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

In a secondary battery, in order to realize high-efficiency discharge and high capacity, a plurality of electrode foils are laminated or wound to form an electrode body. The electrode body is housed inside the case body together with the current collector terminal (also referred to as a current collector), and the external terminal is arranged 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 Application Laid-Open No. 10-106536 (Patent Document 1), the ends of a plurality of current collector foils constituting the electrode body are bundled inside a slit provided in the current collector terminal. It is inserted in a state of being inserted, and both are welded by laser welding. A technique similar to this is also disclosed in Japanese Patent Application Laid-Open No. 2013-179015 (Patent Document 2) and the like.

Japanese Unexamined Patent Publication No. 10-106536 Japanese Unexamined Patent Publication No. 2013-179015

The current collecting terminal used in the 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 slit, and as a result, the current collector terminals are electrodeed. It may be difficult to attach it to the body. On the other hand, when the ends of a plurality of current collector foils are bundled and joined to the current collector terminals by laser welding, if the slit width is wide, that is, if the distance between the two extending portions is wide, the plurality of sheets are present. It becomes difficult to make the end of the current collector foil and the extending part of the current collector terminal contact each other, or the laser for welding passes through the slit and is located inside the current collector terminal. (So-called laser omission) may be reached, and as a result, it may be difficult to perform proper welding.

The present disclosure describes a 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 and stably bonded to the electrode body, and a method for manufacturing the secondary battery. The purpose is to provide.

In the secondary battery based on the present disclosure, the electrode main body portion in which the current collector foils for the positive electrode and the negative electrode are laminated via the separator, and the current collector foils for the positive electrode and the negative electrode are respectively attached to the electrode main body portion. A current collecting foil extending portion extending to the outside of the current collecting foil and a plurality of the current collecting foils constituting the current collecting foil extending portion are formed at the outer tip of the current collecting foil extending portion. The electrode body including the current collecting foil connecting portion and the first extending portion having a shape extending along the longitudinal direction of the collecting foil connecting portion are included, and the first extending portion is the collecting foil connecting portion. A first current collecting terminal welded to the above, and a second extending portion having a shape extending along the longitudinal direction are included, and the second extending portion is welded to the current collecting foil connecting portion. The current collecting terminal and the second current collecting terminal which are separate members are provided, and the first extending portion and the second extending portion are located on opposite sides of the current collecting foil connecting portion. By welding both the first extending portion and the second extending portion to the current collecting foil connecting portion, the first extending portion, the second extending portion, and the current collecting foil connecting portion can be formed. A welded portion to be integrated is formed, and the first current collecting terminal and the second current collecting terminal are integrated via the welded 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 from each other, the first current collecting terminal and the second current collecting terminal are formed in the manufacturing process. By moving and relative to each other, the width of the slit, which is the portion where the current collector foil connecting portion is inserted, can be changed. For example, when inserting the current collector foil connection portion 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 as wide as possible 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 performing laser welding, the first current collector terminal and the second current collector terminal can be arranged so that the slit width becomes narrower, so that the current collector foil connection portion, the first current collector terminal, and the second current collector terminal can be arranged. The electric terminals can be easily brought into contact with each other, and even if laser welding is performed, so-called laser omission 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 collector terminals are formed so as to be adjacent to each other with a gap between them, and the current collector foil connection portion is arranged so as to pass through the gap from the inside to the outside. 1. The first extending portion and the second extending portion of the first extending portion are included, and the first extending portion of the first extending portion includes a flat plate portion extending along the longitudinal direction and a flat plate portion of the flat plate portion. The second extending portion of the second current collecting terminal has a convex portion having a shape protruding outward from the end portion on the side where the current collecting foil connecting portion is arranged, and the second extending portion of the second current collecting terminal is the second one. The welded portion is arranged so as to overlap the outer surface of the first extending portion, and the welded portion is the end portion of the second extending portion on the side where the current collecting foil connecting portion is located and the current collecting foil connecting portion. And the convex portion provided in the first extending portion may be integrated.

According to the above configuration, the first extending portion is compared with the case where the second extending portion is arranged between the first extending portion and the second first extending portion. The gap formed between the first and the second extending portion can be reduced, the first current collecting terminal and the second current collecting terminal can be miniaturized, and the entire secondary battery can be reduced in size. It is also possible to reduce the size of the battery.

In the above configuration, the end portion of the second extending portion on the side where the current collecting foil connecting portion is located and the convex portion provided on the first extending portion are respectively. The outer surface of the surface may be substantially flush with each other.

According to the above configuration, since the first current collecting terminal and the second current collecting terminal are evenly contacted or pressed against the current collecting foil connecting portion from both sides at the time of welding, the current collecting foil connecting portion may be curved. The first current collector terminal and the second current collector terminal can be stably and easily welded to the current collector foil connection portion without bending.

In the above configuration, the welded portion includes a portion of the convex portion other than both ends in the longitudinal direction, the current collector foil connecting portion, and the current collecting foil connecting portion of the second extending portion. It may be provided so as to weld the end portion on the side to be located.

Regarding the above configuration, in the welding process, a state transition is performed in which the current collector foil connection portion to be welded changes from a solid to a liquid and then returns to a solid state, so that the current collector foil connection portion is inserted. The width of the above-mentioned gap, which is a portion, also changes during the welding process. According to the above configuration, the amount of change in the width of the gap can be reduced, and the influence on the state of the welded portion after welding can be reduced. Further, since the separator existing near the welded portion is vulnerable to heat, it is possible to reduce the influence of heat on the separator by shortening the welding length of the welded portion.

In the method for manufacturing a secondary battery based on the present disclosure, an electrode main 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 a positive electrode and a negative electrode are the electrode main bodies, respectively. The current collecting foil extending portion extending to the outside of the portion and the plurality of current collecting foils constituting the current collecting foil extending portion are attached to the outer tip of the current collecting foil extending portion. A step of preparing the electrode body including the formed current collector foil connecting portion and a shape including the first extending portion and the first extending portion extending along the longitudinal direction of the current collecting foil connecting portion. A second current collector that includes a first current collector terminal and a second extending portion, and has a shape in which the second extending portion extends along the longitudinal direction, and is a separate member from the first current collecting terminal. The first current collecting terminal and the first current collecting terminal so that the step of preparing the terminal and the first extending portion and the second extending portion are located on opposite sides of the current collecting foil connecting portion. (2) The first current collecting terminal and the second current collecting terminal are relatively moved so that the first extending portion and the second extending portion are close to each other in the arrangement step of arranging the current collecting terminals. As a result, both the first extending portion and the second extending portion are brought into contact with the current collecting foil connecting portion, and both the first extending portion and the second extending portion are made of the current collecting foil. By performing laser welding in contact with the connecting portion to form a welded portion that integrates the first extending portion, the second extending portion, and the current collecting foil connecting portion, the first extending portion is formed. A welding step of integrating the current collecting terminal and the second current collecting terminal via the welded portion is provided.

According to the above configuration, since the first current collecting terminal and the second current collecting terminal are configured as separate members from each other, the first current collecting terminal and the second current collecting terminal are relatively moved in the manufacturing process. Thereby, the width of the slit, which is the portion where the current collecting foil connecting portion is inserted, can be changed. For example, when inserting the current collector foil connection portion 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 as wide as possible 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 performing laser welding, the first current collector terminal and the second current collector terminal can be arranged so that the slit width becomes narrower, so that the current collector foil connection portion, the first current collector terminal, and the second current collector terminal can be arranged. It is possible to easily bring the electric terminals into contact with each other, and even if laser welding is performed, so-called laser omission does not occur, appropriate welding can be performed, and a high-quality secondary battery can be manufactured. Is possible.

In the above configuration, the first current collector terminals are formed so as to be adjacent to each other with a gap between them, and the current collector foil connecting portion is arranged so as to pass through the gap from the inside to the outside. 1. The first extending portion and the second extending portion of the first extending portion are included, and the first extending portion of the first extending portion includes a flat plate portion extending along the longitudinal direction and a flat plate portion of the flat plate portion. It has a convex portion having a shape protruding outward from the end portion on the side where the current collector foil connection portion is arranged, and the arrangement step involves the second extending portion of the second current collector terminal. The step of forming a slit between the second extending portion and the convex portion by arranging the second extending portion so as to overlap the outer surface of the first extending portion, and the current collecting foil connecting portion are described above. The step of arranging the first current collecting terminal and the second current collecting terminal so as to pass through the slit from the inside to the outside is included, and in the welding step, of the second extending portion. Laser welding in a state where both the end portion on the side where the current collector foil connection portion is located and the convex portion provided on the first first extension portion are in contact with the current collector foil connection portion. Is carried out, and by forming the welded portion, the end portion of the second extending portion on the side where the current collecting foil connecting portion is located, the current collecting foil connecting portion, and the first first The convex portion provided on the extending portion may be integrated with the convex portion.

According to the above configuration, the first extending portion is compared with the case where the second extending portion is arranged between the first extending portion and the second first extending portion. The gap formed between the first and the second extending portion can be reduced, the first current collecting terminal and the second current collecting terminal can be miniaturized, and the entire secondary battery can be reduced in size. It is also possible to reduce the size of the battery.

In the above configuration, when the laser welding is performed, the end portion of the second extending portion on the side where the current collecting foil connecting portion is located and the first extending portion are provided. The convex portions have a relationship in which their outer surfaces are substantially flush with each other.

According to the above configuration, since the first current collecting terminal and the second current collecting terminal are evenly contacted or pressed against the current collecting foil connecting portion from both sides at the time of welding, the current collecting foil connecting portion may be curved. The first current collector terminal and the second current collector terminal can be stably and easily welded to the current collector foil connection portion without bending.

In the above configuration, the welded portion includes a portion of the convex portion other than both ends in the longitudinal direction, the current collector foil connecting portion, and the current collecting foil connecting portion of the second extending portion. It may be provided so as to weld the end portion on the side to be located.

Regarding the above configuration, in the welding process, a state transition is performed in which the current collector foil connection portion to be welded changes from a solid to a liquid and then returns to a solid state, so that the current collector foil connection portion is inserted. The width of the above-mentioned gap, which is a portion, also changes during the welding process. According to the above configuration, the amount of change in the width of the gap can be reduced, and the influence on the state of the welded portion after welding can be reduced. Further, since the separator existing near the welded portion is vulnerable to heat, it is possible to reduce the influence of heat on the separator by shortening the welding length of the welded portion.

According to the present disclosure, a secondary battery and its manufacture 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 bonded to the electrode body. You can get the method.

It is sectional drawing which shows the secondary battery 100 in Embodiment 1. FIG. It is a perspective view which shows the electrode body 30, the 1st current collecting terminal 10 and the 2nd current collecting terminal 20 provided in the secondary battery 100 in Embodiment 1. FIG. It is a figure (side view) which shows the state when the 1st current collector terminal 10 and the 2nd current collector terminal 20 are seen along the arrow III line in FIG. It is a figure (plan view) which shows the state when the 1st current collecting terminal 10 and the 2nd current collecting terminal 20 and the like are seen along the arrow IV line in FIG. It is a cross-sectional view taken along the line VV in FIG. It is a perspective view which shows the disassembled state of the 1st current collecting terminal 10 and the 2nd current collecting terminal 20 provided in the secondary battery 100 in Embodiment 1. FIG. It is a figure for demonstrating the preparation process of the manufacturing method of the secondary battery 100 in Embodiment 1. FIG. It is a figure for demonstrating the arrangement process (first stage) of the manufacturing method of the secondary battery 100 in Embodiment 1. FIG. It is a figure for demonstrating the arrangement process (second stage) of the manufacturing method of the secondary battery 100 in Embodiment 1. FIG. It is a figure for demonstrating the arrangement process (third stage) of the manufacturing method of the secondary battery 100 in Embodiment 1. FIG. It is a figure for demonstrating the welding process of the manufacturing method of the secondary battery 100 in Embodiment 1. FIG. It is a perspective view which shows the secondary battery in the comparative example, the current collector terminal 50 used in the manufacturing method thereof, and the like. It is a figure for demonstrating the arrangement process of the manufacturing method of the secondary battery in the comparative example. It is a figure for demonstrating the welding process of the manufacturing method of the secondary battery in the comparative example. It is a figure for demonstrating the experiment and the result about the comparative example 1 and 2 based on the comparative example, and the example based on Embodiment 1. FIG. It is sectional drawing for demonstrating the manufacturing method of the secondary battery in Embodiment 2. FIG. It is a perspective view which shows the 1st current collector terminal 10 and the 2nd current collector terminal 20A used for the secondary battery in Embodiment 3 and the manufacturing method thereof. It is sectional drawing which shows the 1st current collector terminal 10 and the 2nd current collector terminal 20A used for the secondary battery in Embodiment 3 and the manufacturing method thereof. It is a perspective view which shows the 1st current collector terminal 10B and the 2nd current collector terminal 20B used for the secondary battery in Embodiment 4 and the manufacturing method thereof. It is sectional drawing which shows the 1st current collector terminal 10B and the 2nd current collector terminal 20B used for the secondary battery in Embodiment 4 and the manufacturing method thereof.

The embodiment will be described below with reference to the drawings. The same parts and equivalent parts may be given the same reference number and duplicate explanations may not be repeated.

[Embodiment 1]
(Secondary battery 100)
FIG. 1 is a cross-sectional view showing the secondary battery 100 according to the first embodiment. The 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 for driving a vehicle, for example, and is used for a hybrid vehicle powered by an internal combustion engine such as a gasoline engine or a diesel engine and a motor powered by a rechargeable battery, or an external charge. It will be installed in plug-in hybrid vehicles and electric vehicles that can be used.

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, a positive electrode current collecting terminal 10P, 20P, and a negative electrode current collecting terminal 10N, 20N. Hereinafter, when the positive electrode external terminal 37P and the negative electrode external terminal 37N are not particularly distinguished (in other words, when the configuration common to these is described, the same applies hereinafter), it is simply expressed as "external terminal 37" and is a collection for the positive electrode. When the current collecting terminal 10P and the negative electrode current collecting terminal 10N are not particularly distinguished, they are simply expressed as "first current collecting terminal 10", and when the positive electrode current collecting terminal 20P and the negative electrode current collecting terminal 20N are not particularly distinguished, they are simply expressed. 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 constitutes 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 square tube shape, and the lid 42 is provided so as to close the opening of the main body 41. External terminals 37 (external positive electrode terminal 37P and external negative electrode terminal 37N) are attached to the lid portion 42.

(Electrode body 30)
FIG. 2 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. FIG. 3 is a view (side view) showing a state when the first current collector terminal 10 and the second current collector terminal 20 are viewed along the arrow III line in FIG. 2, and FIG. 4 is a view (side view). FIG. 5 is a view (plan view) showing a state when the first current collector terminal 10 and the second current collector terminal 20 are viewed along the arrow IV line in the middle, and FIG. 5 is a VV line in FIG. It is a cross-sectional view taken along the arrow. FIG. 6 is a perspective view showing a disassembled state of the first current collector terminal 10 and the second current collector terminal 20.

With reference to FIGS. 2 to 6, the electrode body 30 is housed in the case body 40 (see also FIG. 1). The electrode body 30 is composed of a laminate of a plurality of positive electrode current collecting foils 31P, a plurality of separators 31S, and a plurality of negative electrode current collecting 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 made of a porous polypropylene resin sheet or the like. The region of the positive electrode current collector foil 31P coated with the positive electrode active material and the 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 of the positive electrode current collecting foil 31P to which the positive electrode active material is not applied is exposed from one end of the separator 31S in the longitudinal direction, and the negative electrode active material of the negative electrode current collecting foil 31N is applied. The unexposed region is exposed from the other end of the separator 31S in the longitudinal direction.

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

The electrode main body 31 is a portion where the positive electrode current collecting foil 31P and the negative electrode current collecting foil 31N are laminated via the separator 31S. The positive electrode current collecting foil extending portion 32P is a portion where the positive electrode current collecting foil 31P extends from the electrode main body 31 to one side, and the negative electrode current collecting foil extending portion 32N is a negative electrode current collecting foil extending portion 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 collecting foil extending portion 32P and the negative electrode current collecting foil extending portion 32N extend to both outer sides of the electrode main body portion 31. Even if the positive electrode current collecting foil extending portion 32P and the negative electrode current collecting foil extending portion 32N are configured to extend only to the outside (one side) of the electrode main body 31. Good.

In the positive electrode current collecting foil extending portion 32P, a plurality of positive electrode current collecting foils 31P are laminated in the thickness direction of the electrode body 30. By gathering the plurality of positive electrode current collecting foils 31P constituting the positive electrode current collecting foil extending portion 32P so as to converge, a positive electrode is attached to the outer tip of the positive electrode current collecting foil extending portion 32P. A current collector foil connecting portion 33P is formed.

In the negative electrode current collecting foil extending portion 32N, a plurality of negative electrode current collecting foils 31N are laminated in the thickness direction of the electrode body 30. A plurality of negative electrode current collector foils 31N constituting the negative electrode current collector foil extension portion 32N are gathered together so as to converge, so that the negative electrode is attached to the outer tip of the negative electrode current collector foil extension portion 32N. A current collector foil connecting portion 33N is formed. Hereinafter, when the positive electrode current collecting foil connecting portion 33P and the negative electrode current collecting foil connecting portion 33N are not particularly distinguished, they are simply referred to as “current collecting foil connecting portion 33” (see FIGS. 2 to 6).

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

Specifically, the positive electrode current collecting terminals 10P and 20P electrically connect the positive electrode external terminal 37P (FIG. 1) and the positive electrode current collecting foil extending portion 32P (positive electrode current collecting foil connecting portion 33P). Connecting. The positive electrode current collecting terminals 10P and 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 collecting foil 31P.

The negative electrode current collecting terminals 10N and 20N electrically connect the negative electrode external terminal 37N (FIG. 1) and the negative electrode current collecting foil extending portion 32N (negative electrode current collecting 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 superposed on the inner surface (lower surface) of the lid portion 42 via the insulator 35. It is electrically connected to the external terminal 37 via the conductive pin member 34. The first current collecting terminal 10 and the pin member 34 may be integrally molded. The first current collecting terminal 10 has a base portion 16 and extending portions 11 to 14 as constituent portions thereof. The base portion 16 has a portion formed in a flat plate shape, and is superposed on the inner surface of the lid portion 42 via an insulator 35.

The extending portions 11 to 14 extend in a direction away from the base portion 16. Each of the extending portions 11 to 14 has a shape extending in parallel along the longitudinal direction of the current collecting foil connecting portion 33, and a slit S1 (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 across the slit S1 (gap), and are arranged so as to pass through the slit S1 (gap) from the inside to the outside. Is welded to (Fig. 5).

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

The second current collecting terminal 20 is a separate member from the first current collecting terminal 10, and the second current collecting terminal 20 has a base portion 26 and extending portions 21 to 24 as constituent portions thereof. The base portion 26 has a portion formed in a flat plate shape and is superposed on the upper surface of the base portion 16. The extending portions 21 to 24 extend in a direction away from the base 26. Each of the extending portions 21 to 24 has a shape extending along the longitudinal direction of the current collecting foil connecting portion 33, and the outer surface 28 (the region where the welded portion 38 is not formed) of the extending portions 21 to 24 is formed. , 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 across the slit S2 (gap), and are arranged so as to pass through the slit S2 (gap) from the inside to the outside. It is welded to (Fig. 5). In the state before the current collector foil connecting portion 33 is welded to the extending portions 21 to 24, the end portion 29 of each of the extending portions 21 to 24 on the side where the current collecting foil connecting portion 33 is located is. It is parallel to the extending direction (vertical direction in the paper surface of FIG. 5) of the current collecting foil connecting portion 33 (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 by one current collecting foil. The portions 33 are located on opposite sides of each other (with respect to one current collector foil connecting portion 33) (FIG. 5). By welding both the extending portion 11 and the extending portion 21 to the current collecting foil connecting portion 33 located between them, the extending portion 11 and the extending portion 21 and the collecting located between them are welded to each other. 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 via a welded portion 38.

In the present embodiment, the first collector terminal 10 includes a an extending portion 1 1 and the extending portion 1 2, extending portion 21 of the second collector terminal 20 (second extending portion) Is arranged so as to overlap the outer surface of the flat plate portion 17 of the extending portion 12. Weld 38, the end portion 29 of the side where the collector foils connecting portion 33 is located out of the extending portion 21 (second extending portion), a convex portion 18 provided on the extending portion 1 1, these The current collector foil connecting portion 33 located between the two is integrated.

As shown in FIG. 5, the relationship between the extending portions 12 and 22 and the current collecting foil connecting portion 33 located between them, and the relationship between the extending portions 13 and 23 and the collecting foil connecting portion 33 located between them. , And the relationship between the extending portions 14, 24 and the current collecting foil connecting portion 33 located between them is the relationship between the extending portions 11 and 21 and the collecting foil connecting portion 33 located between them. The same is true. In the present embodiment, the first current collecting terminal 10 and the second current collecting terminal 20 are configured as separate members from each other, and are integrated with each other via four welded portions 38.

(Production method)
A method for manufacturing the secondary battery 100 will be described below with reference to FIGS. 7 to 11. With reference to FIG. 7, the electrode body 30 is first prepared. Specifically, a plurality of positive electrode current collecting foils 31P, a plurality of separators 31S, and a plurality of negative electrode current collecting foils 31N are laminated. As a result, the electrode main body 31 in which the positive electrode current collecting foil 31P and the negative electrode current collecting foil 31N are laminated via the separator 31S, and the positive electrode current collecting foil 31P and the negative electrode current collecting foil 31N are respectively electrode main body portions. A laminated body (electrode body 30) including a current collecting foil extending portion 32 extending to both outer sides of 31 (a positive electrode collecting foil extending portion 32P and a negative electrode collecting foil extending portion 32N). Forehead) is obtained. In the laminated body, both the positive electrode current collecting foil 31P and the negative electrode current collecting foil 31N extend to the outside of one of the electrode main body 31, respectively (current collecting foil extending portion 32 for the positive electrode (current collecting for the positive electrode)). The foil extending portion 32P and the current collecting foil extending portion 32N for the negative electrode) may be included.

After that, a jig 60 having an inclined surface brings together a plurality of current collector foils (current collector foil 31P for positive electrode and current collector foil 31N for negative electrode) constituting the current collector foil extending portion 32 so as to converge. Collected. A current collector foil connecting portion 33 (current collector for a positive electrode) having a width W1 (FIG. 8) at the outer tip of the current collector foil extending portion 32 by a plurality of current collecting foils constituting the current collecting foil extending portion 32. The foil connecting portion 33P and the current collecting foil connecting portion 33N for the negative electrode are formed. As described above, the electrode body 30 including the electrode main body portion 31, the current collecting foil extending portion 32, and the current collecting foil connecting portion 33 is prepared.

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

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

(Placement process)
After that, the second current collector terminal 20 is superposed on the outside of the first current collector terminal 10. At this time, each of the convex portions 18 of the extending portions 12 to 14 is inserted into the slit S2 provided in the second current collecting terminal 20. A second current collecting terminal 20 extends between the convex portion 18 of the extending portion 11 (first extending portion) and the convex portion 18 of the extending portion 12 (second first extending portion). The existing portion 21 (second extending portion) is arranged. The extending portion 21 (second extending portion) of the second current collecting terminal 20 is arranged so as to overlap the outer surface of the flat plate portion 17 of the extending portion 12 (second first extending portion). By arranging the extending portions 21 to 23 of the second current collecting terminal 20 so as to overlap the outer surfaces of the extending portions 12 to 14 of the first current collecting terminal 10, they extend to the extending portions 21 to 24, respectively. A slit is formed between each of the convex portions 18 of the existing portions 11 to 14.

With reference to FIG. 9, in the present embodiment, the extending portion 21 (the second) is in a state where the first current collecting terminal 10 and the second current collecting terminal 20 are arranged so as to overlap each other as described above. The end 29 on the side where the current collecting foil connecting portion 33 is located and the convex portion 18 provided on the extending portion 11 (first extending portion) of the two extending portions) are respectively. 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 slit (the gap between the extending portions 11 to 14 (slit S1) and the gap between the extending portions 21 to 24 (slit S2)) is formed in the current collecting foil connecting portion 33. The first current collecting terminal 10 and the second current collecting terminal 20 are arranged so that the first current collector terminal 10 and the second current collector terminal 20 pass from the inside to 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 connected to each other with respect to one current collecting foil connecting portion 33. The first current collecting terminal 10 and the second current collecting terminal 20 are arranged so as to be located on opposite sides (the state shown in FIG. 10 can be obtained). The same applies to the extending portions 12 to 14 and the extending portions 22 to 24.

After that, the first current collecting terminal 10 and the second current collecting terminal 20 move relative to each other so that the extending portion 11 (first extending portion) and the extending portion 21 (second extending portion) approach each other. Here, the slide is moved). The same applies to the extending portions 12 to 14 and the extending portions 22 to 24. By reducing the width W2 (FIG. 9) evenly in the longitudinal direction of the current collecting foil connecting portion 33, all of the extending portions 11 to 14 and the extending portions 21 to 24 are located between them. The connection portion 33 can be evenly contacted.

(Welding process)
With reference to FIG. 11, each of the convex portions 18 of the extending portions 11 to 14 and the end portion 29 of each of the extending portions 21 to 24 on the side where the current collecting foil connecting portion 33 is located are these. Laser welding using the laser L is performed in a state of being in contact with the current collecting 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 a constant value or less), the first current collecting terminal 10 and the second current collecting terminal 20 are arranged 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. Welded portions 38 (FIG. 5) are formed that integrate each of the extending portions 11 to 14, each of the extending portions 21 to 24, and the current collecting foil connecting portion 33 located between them. The first current collecting terminal 10 and the second current collecting terminal 20 are integrated via welded portions 38 (four welded portions 38 in the present embodiment).

In the present embodiment (see FIG. 3), the welded portion 38 is formed with 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 extending portion). , The current collecting foil connecting portion 33 and the end portion 29 (FIG. 5) of the extending portion 21 (second extending portion) on the side where the current collecting foil connecting portion 33 is located are provided so as to be welded. There is. The same applies to the extending portions 12 to 14 and the extending portions 22 to 24.

The pin member 34, the insulator 35, the lid 42, the insulator 36, and the 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 housed 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. The electrolytic solution is injected into the case body 41 through the 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.

(Action and effect)
Hereinafter, the actions and effects of the first embodiment will be described in comparison with the comparative examples shown in FIGS. 12 to 14.

In the case of the comparative example shown in FIG. 12, the current collecting terminal 50 has a base 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 collecting 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 collecting foil connecting portion 33 into the slit S3, and as a result, the current collecting terminal 50 Is difficult to assemble to the electrode body 30.

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, the width of the slit S3 is wide, that is, two adjacent portions. If the distance between the existing portions is wide, it becomes difficult to join the current collecting foil connecting portion 33 and the extending portions 51 to 55 of the current collecting terminal 50 to each other. In this case, the laser L for welding passes through the slit S3 and reaches the current collecting foil or separator located inside the current collecting terminal (so-called laser removal), and as a result, it is difficult to perform proper welding. There is also the possibility of becoming.

On the other hand, according to the secondary battery 100 in the present embodiment, the portion corresponding to the slit is composed of the first current collecting terminal 10 and the second current collecting terminal 20 which are separate members from each other. .. According to the secondary battery 100 having this configuration, when the ends of a plurality of current collector foils (current collector foil connection portions 33) are inserted into the slit in a bundled state, the slit width is the maximum in the movable range. With the first current collector terminal 10 and the second current collector terminal 20 arranged so as to be as wide as possible, the current collector foil connection portion 33 can be inserted into the slit, and the first current collector terminal 10 and the second current collector can be inserted. The terminal 20 can be easily assembled to the electrode body 30.

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

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 attached to the end portion 29 of the extending portion 21 (second extending portion) on the side where the current collecting foil connecting portion 33 is located and the extending portion 11 (first extending portion). The provided convex portion 18 and the current collecting foil connecting portion 33 located between them 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 case of the first embodiment, and the extending portion 21 to the second current collecting terminal 20 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 (the direction perpendicular to the paper surface in FIG. 1) on the same plane. Even in this case, the width of the slit formed between the extending portions 11 to 14, 21 to 24 can be increased or decreased by the relative movement between the first current collecting terminal 10 and the second current collecting terminal 20. Yes, it is possible to obtain substantially the same actions and effects as described above.

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. To. The configuration is not essential, but when the configuration is adopted, the extending portions 11 are compared with the case where the extending portions 11 to 14 and the extending portions 21 to 24 are alternately arranged on the same plane. The width of the slit formed between ~ 14 can be narrowed, and as a result, the width of the first current collecting terminal 10 and the second current collecting terminal 20 as a whole can be reduced, and the secondary battery 100 It is possible to reduce the size of the battery. Further, the welded portion 38 includes an end portion 29 of each of the extending portions 21 to 24, a convex portion 18 provided on each of the extending portions 11 to 14, and a current collecting foil connecting portion 33 located between them. It is possible to carry out necessary and sufficient welding in order to integrate the above.

As described above, in the first embodiment, the end portion 29 of the extending portion 21 (second extending portion) on the side where the current collecting foil connecting portion 33 is located and the extending portion 11 (first first extending portion) are located. The convex portions 18 provided on the 1 extending portion) have 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. The configuration is not essential, but according to the configuration, the respective end portions 29 of the extending portions 21 to 24 and the convex portions 18 provided on each of the extending portions 11 to 14 are collected at the time of welding. Since the current collector foil connection portion 33 is evenly contacted or pressure-welded from both sides to the current collector foil connection portion 33, the current collector foil connection portion 33 does not bend or bend, and the end portion 29 and the convex portion 18 are connected by the current collector foil. It is possible to stably and easily weld to the portion 33.

As described above, in the present embodiment (see FIG. 3), the welded portion 38 includes both ends 18A and 18B in the longitudinal direction of the convex portion 18 of the extending portion 11 (first extending portion). 18H, the current collecting foil connecting portion 33, and the end portion 29 (FIG. 5) of the extending portion 21 (second extending portion) on the side where the current collecting foil connecting portion 33 is located are welded. It is provided in. The same applies to the extending portions 12 to 14 and the extending portions 22 to 24.

Regarding the above configuration, in order to stably weld the extending portions 11 to 14, the extending portions 21 to 24, and the current collecting foil connecting portion 33 between them, the extending portions 11 to 14 (implemented). In the first embodiment, the gap between the convex portion 18) and the extending portions 21 to 24 (end portion 29) is made constant (or a constant value or less), and the first current collecting terminal 10 and the first current collecting terminal 10 are arranged so that the gap becomes small. Laser welding is performed with the second current collector terminal 20 pressurized. In the welding process, the state transition is performed in which the current collecting foil connection portion 33, which is the object of welding, changes from solid to liquid and then returns to solid, so the width of the above gap also changes during the welding process. It becomes.

Here, if an attempt is made to weld the entire region where the current collecting foil connecting portion 33 is sandwiched between the convex portion 18 and the end portion 29, the volume of the welded object to be melted increases by that amount, and the amount of change in the width of the gap also increases. growing. The change in the width of the gap so that it increases and decreases again in the process of welding affects the state of the welded portion 38 after welding, so it is preferable that the amount of change in the width of the gap is as small as possible.

Therefore, in the present embodiment, the welded portion 38 extends from each of the convex portions 18 of the extending portions 11 to 14 to the portions 18H other than the both ends 18A and 18B in the longitudinal direction, and the current collecting foil connecting portion 33. By providing the existing portions 21 to 24 so as to be welded to each end portion 29 (FIG. 5), it is possible to form a good and stable welded portion 38. The separator 31S existing near the welded portion is vulnerable to heat, but by shortening the welding length of the welded portion 38, it is possible to reduce the heat effect on the separator 31S. The welding length of the welded portion 38 required for electrical connection can be determined according to the specifications of the secondary battery 100 and the like. Therefore, the welding length of the welded portion 38 is preferably set to a necessary and sufficient value (for example, 10 mm) including the portions 18H other than 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 relating to Comparative Examples 1 to 3 based on the above-mentioned Comparative Examples and Examples based on the above-mentioned Embodiment 1 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 set to 0.5 mm. The positive electrode current collecting terminal 10P, the positive electrode current collecting terminal 20P, and the current collecting terminal 50 on the positive electrode side were made of aluminum and had a thickness of 0.8 mm. The negative electrode current collecting terminal 10N, the negative electrode current collecting terminal 20N, and the current collecting terminal 50 on the negative electrode side were made of copper and had a thickness of 0.8 mm.

As the 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 the 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. For the others, 10 secondary battery samples were prepared for each of Comparative Examples 1 to 3 and Examples based on the conditions shown in FIG. As evaluation 1, the state of being inserted into the slit of the current collecting foil connecting portion 33 was visually observed, and as evaluation 2, the disassembled welded portion (welded portion 38) was visually observed.

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

(Comparative Example 2)
In Comparative Example 2, the width W3 of the slit S3 (FIG. 13) was set to be 0.9 mm. Regarding evaluation 1, when the current collecting foil connecting portion 33 was inserted into the slit S3, the current collecting foil connecting portion 33 did not collide with the extending portions 51 to 55, and the current collecting foil connecting portion 33 was damaged (foil). Since we did not confirm the occurrence of tearing), the result of evaluation 1 was 10/10. Regarding evaluation 2, it was confirmed in four samples that laser omission occurred in the gap between the current collector foil connecting portion 33 and the extending portions 51 to 55, so 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, the current collecting foil connecting portion 33 can be easily inserted, but when the current collecting foil connecting portion 33 is sandwiched between the extending portions 51 to 55. It is presumed that laser omission occurred frequently.

(Example)
In the embodiment, unlike the cases of Comparative Examples 1 and 2, the component functioning as the current collecting terminal is composed of two components, the first current collecting terminal 10 and the second current collecting terminal 20, which are separate members from each other. To. As a result, a good result of 10/10 was obtained in both evaluations 1 and 2. Therefore, according to the configuration based on the first embodiment, the secondary battery and 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. It can be said that the manufacturing method can be used.

[Embodiment 2]
The method for manufacturing the secondary battery according to the second embodiment will be described with reference to FIG. In the arrangement step according to the first embodiment (FIGS. 8 to 10), the second current collector terminal 20 is superposed on the outside of the first current collector terminal 10, and then the first current collector terminal 10 and the second current collector terminal 10 and the second current collector terminal 20 The current collector foil connecting portion 33 is inserted inside the slit formed between the current terminal 20 and the current collector terminal 20.

As shown in FIG. 16, in the arrangement step, after the current collecting foil connecting portion 33 is inserted into the slit S1 of the first current collecting terminal 10, the second current collecting terminal 20 is superposed on the first current collecting terminal 10. May be good. With this configuration, the same actions and effects as those in the first embodiment can be obtained.

[Embodiment 3]
The secondary battery and the method for manufacturing the secondary battery according to the third embodiment will be described with reference to FIGS. 17 and 18. In the first embodiment described above, the second current collecting terminal 20 is provided with a base portion 26 (FIG. 6), and the extending portions 21 to 24 are formed so as to extend from the L-shaped base portion 26. The second current collecting terminal 20A of the present embodiment includes a flat plate-shaped base portion 27 and extending portions 21 to 24 formed so as to hang down from the base portion 27.

In the case of the first embodiment, it is possible to easily position the second current collector terminal 20 with respect to the first current collector terminal 10 by using the base 26, but the second current collector as in the present embodiment. 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]
The secondary battery and the method for manufacturing the secondary battery according to the fourth embodiment will be described with reference to FIGS. 19 and 20. In the present embodiment, the flat plate portions 17 constituting the extending portions 11 to 13 of the first current collecting terminal 10B are curved in the middle portion in the longitudinal direction, and are formed at the upper ends of the extending portions 11 to 13. Compared to this, the lower end has a structure closer to the inside.

Similarly, regarding the extending portions 21 to 23 of the second current collecting terminal 20B, the extending portions 21 to 23 are curved in the middle portion in the longitudinal direction, and the lower end of the extending portions 21 to 23 (on the base 27 side). It has a structure in which the upper end is closer to the inside than the part). Even when the welded portion is arranged so as to sneak inside the current collector foil connecting portion 33, the same operation and effect as in the first embodiment can be obtained.

Although the embodiments have been described above, the above disclosure contents are examples in all respects and are not restrictive. The technical scope of the present disclosure is indicated by the scope of claims, and is intended to include all modifications within the meaning and scope equivalent to the scope of 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 Extended part, 16,26,27 , 56 base, 17 flat plate, 18 convex, 18A, 18B both ends, 18H part, 18S, 28 outer surface, 19,29 end, 20, 20A, 20B second current collecting terminal, 30 electrode body, 31 electrode body Unit, 31N negative electrode current collector foil, 31P positive electrode current collector foil, 31S separator, 32 current collector foil extension section, 32P positive electrode current collector foil extension section, 32N negative electrode current collector foil extension section, 33 current collector Foil connection part, 33N negative electrode collector foil connection part, 33P positive electrode collector foil connection part, 34 pin member, 35, 36 insulator, 37 external terminal, 37N negative electrode external terminal, 37P positive electrode external terminal, 38 welding Part, 40 case body, 41 main body part, 42 lid part, 60 jigs, 100 secondary batteries, L laser, S1, S2, S3 slits, W1, W2, W3 width.

Claims (8)

An electrode main body portion in which current collector foils for a positive electrode and a negative electrode are laminated via a separator, and a collection in which the current collector foils for a positive electrode and a negative electrode extend outward from the electrode main body portion, respectively. A current collector foil extending portion and a current collecting foil connecting portion formed at an outer tip of the current collecting foil extending portion by a plurality of the current collecting foils constituting the current collecting foil extending portion are included. With the electrode body,
A first current collecting terminal including a first extending portion having a shape extending along the longitudinal direction of the current collecting foil connecting portion, and the first extending portion being welded to the current collecting foil connecting portion.
A second member that includes a 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, and is a member separate from the first current collecting terminal. Equipped with a current collector terminal
The first collector terminal before Symbol is at a first gap is formed so as to be adjacent to each other, the collector foil connecting portion is arranged to pass outwardly of said first gap from the inside The first extending portion and the second extending portion of the first extending portion are included.
The second current collecting terminal is formed so as to be adjacent to each other across the second gap, and the current collecting foil connecting portion is arranged so as to pass through the second gap from the inside to the outside. Including the first said second extending part and the second said second extending part,
The first extending portion and the first extending portion 2 face each other, and the first extending portion and the first extending portion face each other.
The second first extending portion and the second second extending portion face each other,
In a state where the first extending portion and the second second extending portion sandwich the current collecting foil connecting portion between them, the first extending portion and the second extending portion integrated the second extending portion and the collector foil connecting portion are integrated through a welding unit, wherein the first collector terminal and the second collector terminal via the weld Has been
Secondary battery. The first extending portion has a shape that projects outward from a flat plate portion extending along the longitudinal direction and an end portion of the flat plate portion on the side where the current collecting foil connecting portion is arranged. Has a convex part and has
The second extending portion is arranged so as to overlap the outer surface of the second extending portion.
The welded portion is formed on the end of the second second extending portion on the side where the current collecting foil connecting portion is located, the current collecting foil connecting portion, and the first first extending portion. It is integrated with the provided convex portion,
The secondary battery according to claim 1. The end of the second extending portion on the side where the current collecting foil connecting portion is located and the convex portion provided on the first extending portion are outside of each. The surface has a substantially flush relationship,
The secondary battery according to claim 2. The welded portion is located at a portion of the convex portion other than both ends in the longitudinal direction, the current collecting foil connecting portion, and the current collecting foil connecting portion of the second extending portion. Provided to weld the end on the side,
The secondary battery according to claim 2 or 3. It is a method of manufacturing secondary batteries.
An electrode main body portion in which current collector foils for a positive electrode and a negative electrode are laminated via a separator, and a collection in which the current collector foils for a positive electrode and a negative electrode extend outward from the electrode main body portion, respectively. A current collector foil extending portion and a current collecting foil connecting portion formed at an outer tip of the current collecting foil extending portion by a plurality of the current collecting foils constituting the current collecting foil extending portion are included. The process of preparing the electrode body and
A first current collecting terminal including a first extending portion and having a shape in which the first extending portion extends along the longitudinal direction of the collecting foil connecting portion, and a second extending portion including the second extending portion. A step of preparing the first current collecting terminal and the second current collecting terminal, which are separate members from each other, having a shape in which the existing portion extends along the longitudinal direction is provided.
The first current collecting terminal includes a first extending portion and a second extending portion formed so as to be adjacent to each other with a first gap.
The second current collecting terminal includes a first second extending portion and a second second extending portion formed so as to be adjacent to each other with a second gap in between.
The method for manufacturing the secondary battery further
The first extending portion and the first second extending portion face each other, and the second first extending portion and the second second extending portion face each other. Then, the current collector foil connecting portion passes through the first gap and the second gap from the inside to the outside, and becomes the first extending portion and the second extending portion. The first current collector terminal and the second current collector terminal are arranged so that the current collector terminals are located on opposite sides of the current collector foil connection portion.
The first by moving the first current collecting terminal and the second current collecting terminal relative to each other so that the first extending portion and the second extending portion come close to each other. A step of bringing both the first extending portion and the second second extending portion into contact with the current collector foil connecting portion, and
Laser welding is performed in a state where both the first extending portion and the second extending portion are in contact with the current collector foil connecting portion, and the first extending portion is formed. By forming a welded portion that integrates the second extending portion and the current collecting foil connecting portion, the first current collecting terminal and the second current collecting terminal are connected to each other via the welded portion. It is equipped with a welding process to integrate.
How to manufacture a secondary battery. The first extending portion has a shape that projects outward from a flat plate portion extending along the longitudinal direction and an end portion of the flat plate portion on the side where the current collecting foil connecting portion is arranged. Has a convex part and has
The placement step is
By arranging the second extending portion so as to overlap the outer surface of the second extending portion, a slit is formed between the second extending portion and the convex portion. The process of forming and
The step of arranging the first current collecting terminal and the second current collecting terminal so that the current collecting foil connecting portion passes through the slit from the inside to the outside is included.
In the welding step, the end portion of the second extending portion on the side where the current collecting foil connecting portion is located and the convex portion provided on the first extending portion. The laser welding is performed in a state where both are in contact with the current collecting foil connecting portion, and the formation of the welded portion positions the current collecting foil connecting portion of the second extending portion. The end portion on the side, the current collecting 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 of the second extending portion on the side where the current collecting foil connecting portion is located and the first extending portion are provided. The convex portions have a relationship in which their outer surfaces are substantially flush with each other.
The method for manufacturing a secondary battery according to claim 6. The welded portion is located at a portion of the convex portion other than both ends in the longitudinal direction, the current collecting foil connecting portion, and the current collecting foil connecting portion of the second extending portion. Provided to weld the end on the side,
The method for manufacturing a secondary battery according to claim 6 or 7.

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