JP2017084653A - Electrode assembly manufacturing method and electrode assembly - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable the welding state of stacked tabs to be checked.SOLUTION: A method for manufacturing an electrode assembly 3 having a plurality of electrodes (positive electrode 11, negative electrode 12) including tabs 14b, 17b, respectively, comprises a step of preparing tab laminates 21 and 25 which are arranged on conductive members (current collecting plates 16 and 19, protective plates 23 and 27) and have a plurality of stacked tabs 14b and 17b, and a step of welding end faces 21a, 21b, 25a, 25b of tab laminates 21, 25 extending along the lamination direction of the tab laminates 21, 25 to form welded portions at the inside of the end faces 21a, 21b, 25a, 25b of the tab laminates 21, 25. In the preparing step, at least ones of the conductive members (current collecting plates 16, 19, protective plates 23, 27) and the tab laminates 21, 25 have cut-out portions c located at a portion (region R) for forming the welded portions in the tab laminates 21, 25 when viewed from the lamination direction of the tab laminates 21, 25.SELECTED DRAWING: Figure 5

Description

  The present invention relates to a method for manufacturing an electrode assembly and an electrode assembly.

  Patent Document 1 discloses a technique in which an opening is formed in a metal member located on the heat source side among the stacked metal members and welding is performed. According to Patent Document 1, the welding state is confirmed by visual observation of the opening.

JP 2010-94730 A

  For example, a power storage device such as a lithium ion battery includes an electrode assembly in which a plurality of electrodes are stacked. Each electrode has a tab, and when manufacturing the electrode assembly, the tabs of the stacked electrodes are welded. Japanese Patent Application Laid-Open No. 2004-133867 does not discuss any such welding of stacked electrode tabs.

  An object of one aspect of the present invention is to provide an electrode assembly manufacturing method and an electrode assembly capable of confirming a welded state of stacked tabs.

  A method for manufacturing an electrode assembly according to one aspect of the present invention is a method for manufacturing an electrode assembly having a plurality of electrodes each including a tab, the tab having a plurality of tabs arranged on a conductive member and stacked. Preparing a laminate, and forming a welded portion from the end surface of the tab laminate by welding the end surface of the tab laminate extending along the lamination direction of the tab laminate, and In the step of preparing, at least one of the conductive member and the tab laminate has a notch portion positioned at a portion for forming a welded portion in the tab laminate when viewed from the lamination direction of the tab laminate.

  In the method for manufacturing the electrode assembly, a welded portion is formed on the inner side from the end surface of the tab laminate by welding the end surfaces of the tab laminate. Here, at least one of the conductive member and the tab laminate has a notch portion positioned at a portion for forming a welded portion in the tab laminate when viewed from the lamination direction of the tab laminate. Therefore, when the welded portion is formed, the molten tab flows into the cutout portion. For example, as the welded portion is formed over a wider area, the amount of molten tab that flows into the cutout portion increases, and a larger portion of the cutout portion is filled. Therefore, it is possible to confirm the welded state of the stacked tabs based on the state of the cutout portion, which is how much the cutout portion is filled with the melted tab.

  The cutout portion may be provided in a portion of the conductive member adjacent to the portion for forming the welded portion. Moreover, a notch part may be provided in the end surface of a tab laminated body. For example, by providing the cutout portion in this way, the melted tab can flow into the cutout portion when the welded portion is formed.

  When the notch is provided in the portion of the conductive member adjacent to the portion for forming the welded portion, in the preparing step, when the tab laminate and the conductive member are viewed from the stacking direction of the tab laminate, the cutout portion is cut. A part of the notch portion may be located outside the end face of the tab laminate. If a notch is provided in a portion of the conductive member adjacent to the portion for forming the weld, the notch may be covered with the tab laminate. When the cutout portion is completely covered, it is difficult for air to be discharged from the cutout portion when the molten tab flows into the cutout portion, and there is a possibility that the molten tab does not flow into the cutout portion. Here, according to the said structure, when seeing a tab laminated body and an electrically-conductive member from the lamination direction of a tab laminated body, a part of notch part is located in the outer side of the end surface of a tab laminated body. For this reason, a part of notch part is exposed without being covered with a tab laminated body, and air is reliably discharged | emitted from the part. Therefore, it becomes easy for the melted tab to flow into the notch.

  The notch may be provided so as to extend in the direction from the end face of the tab laminate to the inside. The welded portion formed on the end face of the tab laminate becomes longer in the direction from the end face toward the inside as the welding is sufficiently performed. If the notch is provided so as to extend in such a direction, the more the welding is performed, the larger the amount of the molten tab that flows into the notch. Based on the state of such a notch, the welding state of the stacked tabs can be confirmed more appropriately.

  In the step of preparing, the length of the notch part may be equal to the length of the part for forming the welded part in the direction from the end face of the tab laminate to the inside. Thereby, it can prevent that the length of a notch becomes longer than needed.

  An electrode assembly according to an aspect of the present invention is an electrode assembly including a plurality of electrodes each including a tab, and a tab laminate including a conductive member and a plurality of tabs stacked on the conductive member. The tab laminate includes a welded portion located on the inner side from the end surface of the tab laminate extending in the stacking direction of the tab laminate, and at least one of the conductive member and the tab laminate is a tab A notch having a first portion located in the welded portion when viewed from the stacking direction of the laminate, and a second portion adjacent to the first portion in the direction from the end face of the tab laminate to the inside. The first part is filled with the same material as the material of the welded part, and the second part is a gap.

  In the above electrode assembly, the first portion located in the welded portion of the cutout portion when viewed from the stacking direction of the tab laminate is buried with the same material as the material of the welded portion. The second part adjacent to the first part in the direction from the end face of the body toward the inside is a gap. In this case, since the first portion corresponds to a portion into which the melted tab flows in the notch portion, for example, based on the state of the notch portion such as how much the first portion occupies in the notch portion. Thus, the welded state of the stacked tabs can be confirmed. Further, since the second portion corresponds to a portion where the melted tab does not flow in the cutout portion, for example, based on the state of the cutout portion such as how much the second portion occupies in the cutout portion. Thus, the welded state of the stacked tabs can also be confirmed.

  In the direction from the end surface of the tab laminate to the inside, the tip of the notch may be located inside the tip of the weld. In this case, since the melted tab does not easily flow into a portion of the cutout portion located inside the tip of the welded portion, the above-described second portion can be easily secured.

  According to one aspect of the present invention, a method for manufacturing an electrode assembly and an electrode assembly capable of confirming a welded state of stacked tabs are provided.

It is sectional drawing of an electrical storage apparatus provided with the electrode assembly which concerns on embodiment. It is sectional drawing of the electrical storage apparatus along the II-II line | wire of FIG. It is a perspective view of the electrode assembly concerning an embodiment. It is a figure which shows typically a part of electrode assembly of FIG. It is a 1st figure which shows 1 process of the manufacturing method of the electrode assembly which concerns on embodiment. It is a 2nd figure which shows 1 process of the manufacturing method of the electrode assembly which concerns on embodiment. It is a 3rd figure which shows 1 process of the manufacturing method of the electrode assembly which concerns on embodiment. It is a 1st figure showing typically a part of electrode assembly concerning the 1st modification. It is the 2nd figure showing typically a part of electrode assembly concerning the 1st modification. It is the 1st figure showing typically a part of electrode assembly concerning the 2nd modification. It is the 2nd figure showing typically a part of electrode assembly concerning the 2nd modification. It is a 1st figure showing typically a part of electrode assembly concerning the 3rd modification. It is the 2nd figure showing typically a part of electrode assembly concerning the 3rd modification. It is a figure which shows typically a part of electrode assembly which concerns on a 4th modification.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the description of the drawings, the same reference numerals are used for the same or equivalent elements, and redundant descriptions are omitted. In the drawing, an XYZ coordinate system is shown as necessary. The Z-axis direction is, for example, the vertical direction, and the X-axis direction and the Y-axis direction are, for example, horizontal directions.

  FIG. 1 is a cross-sectional view of a power storage device including the electrode assembly according to the embodiment. FIG. 2 is a cross-sectional view of the power storage device taken along line II-II in FIG. 1 and 2 is a nonaqueous electrolyte secondary battery such as a lithium ion secondary battery or an electric double layer capacitor.

  As shown in FIGS. 1 and 2, the power storage device 1 includes a hollow case 2 having, for example, a substantially rectangular parallelepiped shape, and an electrode assembly 3 accommodated in the case 2. Case 2 is made of a metal such as aluminum. The case 2 has a main body 2a that is open on one side and a lid 2b that closes the opening of the main body 2a. On the inner wall surface of the case 2, an insulating film (not shown) is provided. For example, a non-aqueous (organic solvent) electrolytic solution is injected into the case 2. In the electrode assembly 3, the positive electrode active material layer 15 of the positive electrode 11, the negative electrode active material layer 18 of the negative electrode 12, and the separator 13 described later are porous, and the electrolyte is impregnated in the pores. A positive electrode terminal 5 and a negative electrode terminal 6 are spaced apart from each other on the lid 2 b of the case 2. The positive electrode terminal 5 is fixed to the case 2 via an insulating ring 7, and the negative electrode terminal 6 is fixed to the case 2 via an insulating ring 8.

  The electrode assembly 3 is a stacked electrode assembly. The electrode assembly 3 includes a plurality of positive electrodes 11 (electrodes), a plurality of negative electrodes 12 (electrodes), and a bag-shaped separator 13 disposed between the positive electrodes 11 and the negative electrodes 12. For example, the positive electrode 11 is accommodated in the separator 13. In a state where the positive electrode 11 is accommodated in the separator 13, the plurality of positive electrodes 11 and the plurality of negative electrodes 12 are alternately stacked via the separators 13.

  The positive electrode 11 includes, for example, a metal foil 14 made of an aluminum foil and a positive electrode active material layer 15 formed on both surfaces of the metal foil 14. The metal foil 14 of the positive electrode 11 includes a rectangular main body 14a and a rectangular tab 14b protruding from one end of the main body 14a. The positive electrode active material layer 15 is a porous layer formed including a positive electrode active material and a binder. The positive electrode active material layer 15 is formed by supporting a positive electrode active material on at least the central portion of the main body 14a on both surfaces of the main body 14a.

  The tab 14b extends upward from the upper edge portion of the main body 14a, and is connected to the positive electrode terminal 5 via a current collector plate 16 (conductive member). The current collector plate 16 is disposed between the tab 14 b and the positive electrode terminal 5. For example, the current collector plate 16 is formed in the shape of a rectangular flat plate from the same material as the metal foil 14 of the positive electrode 11. The plurality of stacked tabs 14b are disposed between the current collector plate 16 and a protective plate 23 (conductive member) thinner than the current collector plate 16 (see FIG. 3). The protection plate 23 is configured in a rectangular flat plate shape from the same material as the metal foil 14 of the positive electrode 11, for example.

  The negative electrode 12 includes a metal foil 17 made of, for example, copper foil, and a negative electrode active material layer 18 formed on both surfaces of the metal foil 17. Similar to the metal foil 14 of the positive electrode 11, the metal foil 17 of the negative electrode 12 includes a rectangular main body 17a and a rectangular tab 17b protruding from one end of the main body 17a. The negative electrode active material layer 18 is formed by supporting a negative electrode active material on at least a central portion of the main body 17a on both surfaces of the main body 17a. The negative electrode active material layer 18 is a porous layer formed including a negative electrode active material and a binder.

  Examples of the negative electrode active material include graphite, highly oriented graphite, carbon such as mesocarbon microbeads, hard carbon, and soft carbon, alkali metals such as lithium and sodium, metal compounds, SiOx (0.5 ≦ x ≦ 1.5 ) And the like, and boron-added carbon. Here, as an example, the tab 17b does not carry a negative electrode active material. However, an active material may be carried on the base end portion of the tab 17b on the main body 17a side.

  The tab 17b extends upward from the upper edge of the main body 17a and is connected to the negative electrode terminal 6 via a current collector plate 19 (conductive member). The current collector plate 19 is disposed between the tab 17 b and the negative electrode terminal 6. For example, the current collector plate 19 is formed in a rectangular flat plate shape from the same material as the metal foil 17 of the negative electrode 12. The plurality of stacked tabs 17b are disposed between the current collector plate 19 and a protective plate 27 (conductive member) thinner than the current collector plate 19 (see FIG. 3). For example, the protection plate 27 is formed in a rectangular flat plate shape from the same material as the metal foil 17 of the negative electrode 12.

  The separator 13 houses the positive electrode 11. The separator 13 has a rectangular shape when viewed from the stacking direction of the positive electrode 11 and the negative electrode 12. For example, the separator 13 is formed in a bag shape by welding a pair of long sheet-like separator members to each other. Examples of the material of the separator 13 include a porous film made of a polyolefin resin such as polyethylene (PE) and polypropylene (PP), a woven fabric or a non-woven fabric made of polypropylene, polyethylene terephthalate (PET), methylcellulose and the like.

  FIG. 3 is a perspective view of the electrode assembly according to the embodiment. FIG. 4 is a diagram schematically showing a part of the electrode assembly of FIG. 3 as viewed from the Z-axis direction. The electrode assembly 3 shown in FIG. 3 includes a plurality of positive electrodes 11 and a plurality of negative electrodes 12 that are stacked on each other with a separator 13 interposed therebetween. Each of the plurality of positive electrodes 11 includes a main body 14a extending in the XY plane and a tab 14b protruding from one end of the main body 14a in the X-axis direction. Each of the plurality of negative electrodes 12 includes a main body 17a extending in the XY plane and a tab 17b protruding from one end of the main body 17a in the X-axis direction. The tabs 14b and 17b are laminated with each other to form tab laminated bodies 21 and 25, respectively. That is, the electrode assembly 3 includes a tab laminate 21 having a plurality of tabs 14b laminated in the Z-axis direction and a tab laminate 25 having a plurality of tabs 17b laminated in the Z-axis direction. The tab laminates 21 and 25 are arranged apart from each other in the Y-axis direction.

  First, the tab laminate 21 and the surrounding structure will be described. The tab laminated body 21 includes end surfaces 21a, 21b, and 21c of the tab laminated body 21 that extend along the lamination direction (Z-axis direction) of the tab laminated body 21. The end surfaces 21a and 21b are surfaces that sandwich the tab laminate 21, and the end surface 21c is a surface that connects the end surfaces 21a and 21b. That is, the end faces 21a and 21b are arranged to face each other with the tab laminate 21 interposed therebetween. The end faces 21a and 21b are faces along the XZ plane. Further, the end surface 21c is a surface that is inclined with respect to the XY plane so that the thickness of the tab laminated body 21 becomes smaller toward the tip of the tab laminated body 21.

  The tab laminate 21 is disposed between the current collector plate 16 and the protection plate 23 in the Z-axis direction. The tab laminate 21 is disposed on the current collector plate 16 in the Z-axis direction. It can be said that the tab laminate 21 is disposed on the protective plate 23 in the Z-axis direction. The protection plate 23 and the current collector plate 16 are not in contact with each other and are separated with the tab laminate 21 sandwiched in the stacking direction. The tab laminate 21 is thicker than the protective plate 23, and the current collector plate 16 is thicker than the protective plate 23.

  The length of the current collector plate 16 in the Y-axis direction is larger than the length of the tab laminate 21 in the Y-axis direction (the distance between the end faces 21a and 21b). In the Y-axis direction, the position of the outer end portion of the current collector plate 16 in the Y-axis direction coincides with the position of the end portion of the main body 14a in the Y-axis direction. The length of the protective plate 23 in the Y-axis direction is substantially the same as the length of the tab laminate 21 in the Y-axis direction.

  The tab laminated body 21 has welded portions W located on the inner sides from the end faces 21 a and 21 b of the tab laminated body 21. The welded portion W extends to the inside of the current collector plate 16 and the protective plate 23 adjacent to the end surfaces 21a and 21b. In the end faces 21a and 21b, the length of the welded portion W in the X-axis direction is preferably substantially equal to the length of the protective plate 23 in the X-axis direction or shorter than the length of the protective plate 23 in the X-axis direction. Thereby, even if the tab 14b of the tab laminated body 21 is displaced in the X-axis direction (for example, when there is a displacement due to tolerance), the welded portion W can be stably formed. If the length of the welded portion W in the X-axis direction is substantially equal to the length of the protective plate 23 in the X-axis direction, the welded portion W may protrude outside the protective plate 23 in the X-axis direction due to positional displacement. Further, when the length of the welded portion W in the X-axis direction is longer than the length of the protective plate 23 in the X-axis direction, the welded portion W protrudes outside the protective plate 23 in the X-axis direction. Even in those cases, the welded portion W can be formed.

  In the electrode assembly 3, at least one of the conductive member (here, the current collector plate 16 or the protective plate 23) and the tab laminate 21 has a notch. In the example shown in FIG. 4, the current collector plate 16 has a notch C. The notch C is formed by processing a part of the current collector plate 16. As a processing method, for example, punching, pressing, or the like may be used. The notch C is provided so as to extend inward from the end faces 21a and 21b of the tab laminate 21 (in the Y axis negative direction in the case of the end face 21a and in the Y axis positive direction in the case of the end face 21b). In the direction, the front end of the notch C is located inside the front end of the weld W. For example, when the cutout portion C extends inward from the same position as the end surfaces 21 a and 21 b of the tab laminate 21, the length of the cutout portion C is longer than the length of the welded portion W. In the direction from the end surface 21a toward the inside, the distance between the end surface 21a and the tip of the notch C may be about 2 mm to 5 mm, for example. In the direction from the end surface 21b toward the inside, the distance between the end surface 21b and the tip of the notch C may be about 2 mm to 5 mm, for example. The notch C has, for example, a substantially rectangular shape when viewed from the Z-axis direction. Further, the notch C has, for example, a substantially rectangular cross-sectional shape when viewed from the extending direction (Y-axis direction) (see FIG. 5 and the like).

  The notch C has a first portion C1 and a second portion C2. The first portion C <b> 1 is a portion located in the welded portion W when viewed from the stacking direction (Z-axis direction) of the tab stacked body 21. The first portion C1 is also a portion adjacent to the welded portion W in the Z-axis direction. The second portion C2 is a portion adjacent to the first portion C1 in the direction from the end surfaces 21a and 21b of the tab laminate 21 to the inside.

  In the example shown in FIG. 4, three cutout portions C having a first portion C1 located at the welded portion W located on the inner side from the end surface 21a of the tab laminate 21 are arranged side by side in the X-axis direction. . The notches C are located at both end portions and the center portion of the welded portion W in the X-axis direction. Each notch C is located on the inner side (Y-axis negative direction side) than the end surface 21 a of the tab laminate 21. Similarly, three notches C having a first portion C1 located in the welded portion W located on the inner side from the end surface 21b of the tab laminated body 21 are arranged side by side in the X-axis direction. Each notch C is located on the inner side (Y-axis positive direction side) than the end surface 21 b of the tab laminate 21. The notches C are located at both ends and the center of the weld W in the X-axis direction. However, the shape and number of the notches C are not limited to the example shown in FIG.

  The first portion C <b> 1 is filled with the same material as the material of the welded portion W included in the tab laminate 21. The first portion C1 is formed by the melted tab 14b (melted tab) flowing into the notch C when the welded portion W is formed. That is, the first portion C1 is a portion of the cutout portion C into which the molten tab has flowed. On the other hand, the second portion C2 is not filled with the same material as the material of the welded portion W and is a gap. The second portion C2 is a portion of the cutout portion C where the molten tab did not flow.

  Next, the tab laminate 25 and the surrounding structure will be described. Similar to the tab laminated body 21, the tab laminated body 25 includes end surfaces 25 a, 25 b, and 25 c of the tab laminated body 25 extending along the lamination direction (Z-axis direction) of the tab laminated body 25. The end surfaces 25a and 25b are surfaces that sandwich the tab laminate 25, and the end surface 25c is a surface that connects the end surfaces 25a and 25b. In other words, the end faces 25a and 25b are arranged to face each other with the tab laminate 25 interposed therebetween. The end surfaces 25a and 25b are surfaces along the XZ plane. Further, the end surface 25c is a surface that is inclined with respect to the XY plane so that the thickness of the tab laminated body 25 becomes smaller toward the tip of the tab laminated body 25.

  The tab laminate 25 is disposed between the current collector plate 19 and the protection plate 27 in the Z-axis direction. The tab laminate 25 is disposed on the current collector plate 19 in the Z-axis direction. It can be said that the tab laminate 25 is disposed on the protective plate 27 in the Z-axis direction. The protection plate 27 and the current collector plate 19 are not in contact with each other and are separated with the tab laminate 25 sandwiched in the stacking direction. The tab laminate 25 is thicker than the protective plate 27, and the current collector plate 19 is thicker than the protective plate 27.

  The length of the current collector plate 19 in the Y-axis direction is larger than the length of the tab laminate 25 in the Y-axis direction (the distance between the end faces 25a and 25b). In the Y-axis direction, the position of the outer end portion of the current collector plate 19 in the Y-axis direction matches the position of the end portion of the main body 17a in the Y-axis direction. The length of the protection plate 27 in the Y-axis direction is substantially the same as the length of the tab laminate 25 in the Y-axis direction.

  The tab laminated body 25 has welded portions W located on the inner side from the end faces 25a and 25b of the tab laminated body 25, respectively. The end surface 25 b of the tab laminated body 25 faces the end surface 21 b of the tab laminated body 21. Therefore, the end faces 21a, 21b, 25a, and 25b of the tab laminates 21 and 25 are arranged along the Y-axis direction. The welded portion W extends to the inside of the current collector plate 19 and the protection plate 27 adjacent to the end surfaces 25a and 25b. In the end surfaces 25a and 25b, the length of the welded portion W in the X-axis direction is preferably substantially equal to the length of the protective plate 27 in the X-axis direction or shorter than the length of the protective plate 27 in the X-axis direction. Thereby, even if the tab 17b of the tab laminated body 25 is displaced in the X-axis direction (for example, when there is a displacement due to tolerance), the welded portion W can be stably formed. When the length of the welded portion W in the X-axis direction is substantially equal to the length of the protective plate 27 in the X-axis direction, the welded portion W may protrude outside the protective plate 27 in the X-axis direction due to positional displacement. When the length of the welded portion W in the X-axis direction is longer than the length of the protective plate 27 in the X-axis direction, the welded portion W protrudes outside the protective plate 27 in the X-axis direction. Even in those cases, the welded portion W can be formed.

  The current collector plate 19 has a notch C as with the current collector plate 16. The notch C is formed by processing a part of the current collector plate 19. The processing method may be the same as that of the current collector plate 16. The notch C is provided so as to extend inward from the end faces 25a and 25b of the tab laminate 25 (in the Y axis positive direction in the case of the end face 25a and in the Y axis negative direction in the case of the end face 25b). In the direction, the front end of the notch C is located inside the front end of the weld W. For example, when the cutout portion C extends inward from the same position as the end faces 25a and 25b of the tab laminate 25, the length of the cutout portion C is longer than the length of the welded portion W. In the direction from the end surface 25a toward the inside, the distance between the end surface 25a and the tip of the notch C may be about 2 to 5 mm, for example. In the direction from the end face 25b toward the inside, the distance between the end face 25b and the tip of the notch C may be about 2 to 5 mm, for example.

  The first portion C1 of the cutout portion C is a portion located at the welded portion W when viewed from the stacking direction (Z-axis direction) of the tab stacked body 25. The first portion C1 is also a portion adjacent to the welded portion W in the Z-axis direction. The second portion C2 is a portion adjacent to the first portion C1 in the direction from the end surfaces 25a and 25b of the tab laminate 25 toward the inside.

  In the example shown in FIG. 4, three cutout portions C having a first portion C1 located at the welded portion W located on the inner side from the end surface 25a of the tab laminate 25 are arranged side by side in the X-axis direction. . The notches C are located at both end portions and the center portion of the welded portion W in the X-axis direction. Each notch C is located on the inner side (Y-axis positive direction side) than the end face 25a of the tab laminate 25. Similarly, three notches C having a first portion C1 located in the welded portion W located on the inner side from the end face 25b of the tab laminated body 25 are arranged side by side in the X-axis direction. Each notch C is located on the inner side (Y-axis negative direction side) than the end face 25 b of the tab laminate 25. The notches C are located at both ends and the center of the weld W in the X-axis direction. However, the shape and number of the notches C are not limited to the example shown in FIG.

  The first portion C <b> 1 is filled with the same material as the material of the welded portion W included in the tab laminate 25. The first portion C1 is formed by the melted tab 17b (melted tab) flowing into the notch C when the welded portion W is formed. That is, the first portion C1 is a portion of the cutout portion C into which the molten tab has flowed. On the other hand, the second portion C2 is not filled with the same material as the material of the welded portion W and is a gap. The second portion C2 is a portion of the cutout portion C where the molten tab did not flow.

  In the electrode assembly 3 described above, the first portion C1 of the cutout portion C is filled with the same material as the material of the welded portion W, while the second portion C2 is a gap. Since the first portion C1 corresponds to a portion into which the molten tab has flowed, for example, the first portion C1 is laminated based on the state of the cutout portion C such as how much the first portion C1 occupies in the cutout portion C. The welding state of the tabs 14b and 17b can be confirmed. Further, since the second portion C2 corresponds to a portion where the molten tab did not flow in the notch portion C, for example, the notch portion C such as what ratio the second portion C2 occupies in the notch portion C. Based on this state, the welded state of the stacked tabs 14b and 17b can also be confirmed. Confirmation of the welding state can be performed, for example, by X-ray inspection, ultrasonic inspection, or the like.

  In addition, when the notch C is entirely filled with the same material as the material of the welded portion W, that is, when the notch C does not have the second portion C2, the notch C is second. Since it becomes easy to confirm the state of the notch C by having the part C2, it becomes easy to confirm the welding state of the laminated tabs 14b and 17b more accurately.

  Further, the front end of the notch C is positioned inside the front end of the welded portion W in the direction from the end surfaces 21 a, 21 b, 25 a, 25 b of the tab laminates 21, 25 toward the inside. In this case, since the molten tab does not easily flow into a portion of the cutout portion C located inside the tip of the welded portion W, the second portion C2 can be easily secured.

  5-7 is a figure which shows 1 process of the manufacturing method of the electrode assembly which concerns on embodiment. The electrode assembly 3 shown in FIG. 3 is manufactured, for example, by the following method.

(Preparation process of tab laminate)
First, as shown in FIG. 5, a plurality of tab laminates 21 and 25 are prepared. 5A is a diagram showing the tab laminates 21 and 25 viewed from the X-axis direction, and FIG. 5B is a diagram showing the tab laminate 25 viewed from the Y-axis direction. For example, first, tab laminates 21 and 25 are formed by laminating tabs 14b and 17b on current collector plates 16 and 19, respectively. Thereafter, the protection plates 23 and 27 are placed on the tab laminates 21 and 25, respectively. The tab laminates 21 and 25 are pressed through the protective plates 23 and 27, but may not be pressed. Here, the current collector plates 16 and 19 have a notch C. However, at this time, since the welded portion W has not yet been formed, the entire cutout portion C is a void. For this reason, the notch part C does not have the above-mentioned 2nd part C2. At least a part of the notch C is located in a portion (region R) for forming the welded portion W in the tab laminates 21 and 25 when viewed from the stacking direction of the tab laminates 21 and 25. . In the stacking direction, at least a part of the notch C is adjacent to the region R. The notch C is formed in the current collecting plates 16 and 19 in advance, for example, before the tabs 14b and 17b are laminated on the current collecting plates 16 and 19, respectively.

(Formation process of welded part)
Next, as shown in FIG. 6, the end surface 25 a of the tab laminate 25 is irradiated with the energy beam B. 6A is a diagram showing the tab laminates 21 and 25 viewed from the X-axis direction, and FIG. 6B is a diagram showing the tab laminate 25 viewed from the Y-axis direction. The energy beam B is irradiated from the irradiation device 30 toward the end surface 25a of the tab laminate 25. The irradiation device 30 is a scanner head including a lens and a galvanometer mirror, for example. A beam generator is connected to the scanner head via a fiber. Irradiation device 30 may be composed of a refractive optical system such as a prism.

  The energy beam B is a high energy beam that can be welded. The energy beam B is, for example, a laser beam or an electron beam. The irradiation with the energy beam B is performed in an atmosphere of an inert gas G supplied from the nozzle 32.

  The energy beam B is applied to the end surface 25a of the tab laminated body 25 in a state where the tab laminated body 25 is pressed in the Z-axis direction via the current collector plate 19 and the protective plate 27 by a jig, for example.

  The energy beam B is scanned along the direction intersecting the Z-axis direction (X-axis direction) on the end surface 25a of the tab laminate 25. In the present embodiment, scanning is performed along the X-axis direction while displacing the energy beam B in the Z-axis direction. For example, the energy beam B is scanned along the X-axis direction while being reciprocally displaced (wobbled) in the Z-axis direction. The amount of displacement of the irradiation spot of the energy beam B in the Z-axis direction is larger than the thickness of the tab laminate 25. The irradiation spot of the energy beam B moves from the position P1 on the axis along the X-axis direction to the position P2 on the end face 25a of the tab laminate 25. For example, the positions P1 and P2 are located at the center of the end face 25a of the tab laminate 25 in the Z-axis direction. For example, the energy beam B is scanned while moving the center point along the X-axis direction on the end face 25a of the tab laminate 25 and rotating the energy beam B in the XZ plane around the center point. When the diameter of rotation is larger than the thickness of the tab laminate 25, it is preferable because the end face 25a of the tab laminate 25, the current collector 19 and the protective plate 27 can be welded as a whole.

  Similarly, the end surface 25b of the tab laminate 25 is also irradiated with the energy beam B. Further, the end surfaces 21 a and 21 b of the tab laminate 21 are also irradiated with the energy beam B.

  By irradiating the energy beam B as described above, as shown in FIG. 7, welded portions W are formed on the inner side from the end surfaces 21 a and 21 b of the tab laminated body 21 and the end surfaces 25 a and 25 b of the tab laminated body 25, respectively. The FIG. 7 is a view showing the structure of the tab laminates 21 and 25 and their surroundings as seen from the X-axis direction. As shown in FIG. 7, when the welded portion W is formed, the melted tab laminates 21 and 25 flow into the cutout portion C, so that the cutout portion C becomes the first portion C1 and the second portion C2. Part C2.

  The electrode assembly 3 is manufactured through the above steps. Thereafter, the electrode assembly 3 obtained by bending the tab laminates 21 and 25 is accommodated in the case 2, and the power storage device 1 can be manufactured.

  As described above, in the electrode assembly manufacturing method of the embodiment, the welded portions W are formed on the inner sides from the respective end surfaces by welding the end surfaces 21a, 21b, 25a, 25b of the tab laminates 21, 25. . The current collector plate 16 is cut at a portion (region R) for forming the welded portion W in the tab laminates 21 and 25 when viewed from the stacking direction (Z-axis direction) of the tab laminates 21 and 25. Has a notch. Therefore, when the weld W is formed, the molten tab flows into the notch C. Here, for example, as the welded portion W is formed over a wide range, the amount of flow of the molten tab into the cutout portion C increases, and a larger portion of the cutout portion C is filled. That is, the proportion of the first portion C1 in the cutout portion C increases. Based on the state of the notch C, such as how much the notch C is filled with the molten tab, the welded state of the stacked tabs 14b and 17b can be confirmed.

  Here, for example, when the number of stacked tabs 14b and 17b is greater than 2, in the technique of forming an opening only in the metal member located on the heat source side as in Patent Document 1, welding is performed second from the heat source side. The welding state of the tab behind is not confirmed. On the other hand, according to the manufacturing method of the electrode assembly, the welding state of the stacked tabs 14b and 17b can be confirmed without depending on the number of stacked tabs 14b and 17b. Does not occur.

  The cutout portion C is provided so as to extend inward from the end faces 21a, 21b, 25a, 25b of the tab laminates 21, 25. The welded portion W becomes longer in the direction from the end surfaces 21a, 21b, 25a, and 25b toward the inside as the welding is sufficiently performed. By providing the cutout portion C so as to extend in such a direction, the amount of flow of the molten tab into the cutout portion C increases as welding is sufficiently performed. Based on such a state of the notch C, it is possible to more appropriately check the welded state of the stacked tabs 14b and 17b.

  The cutout portion C is provided in a portion adjacent to the region R in the current collector plates 16 and 19. For example, by providing the cutout portion C in this way, the molten tab can flow into the cutout portion C when the welded portion W is formed.

  Moreover, in the said embodiment, the notch part C is each located in three places, the both ends part of the welding part W in a X-axis direction, and a center part. By confirming the state of the notch C at each position in the X-axis direction, the welding state of the tabs 14b and 17b can be confirmed more appropriately.

  Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the invention.

(First modification)
For example, in the above-described embodiment, the example in which the notch portion is located on the inner side of the end surface of the tab laminate is described, but a part of the notch portion may be located on the outer side of the end surface of the tab laminate. Good. 8 and 9 are views schematically showing a part of the electrode assembly according to such a modification.

  FIG. 8 is a view of a part of the electrode assembly in a state before the weld W is formed, as viewed from the Z-axis direction. As shown in FIG. 8, a part of the notch C is formed on the outer side of the end surfaces 21a, 21b, 25a, 25b of the tab laminates 21, 25 (in the case of the end surfaces 21a, 25b, the Y axis positive direction side, the end surface 21b). , 25a is located on the Y axis negative direction side).

  In the example shown in FIG. 8, each notch portion C located on the end surface 21a side of the tab laminate 21 and each notch portion C located on the end surface 21b side are connected to each other and extend in the Y-axis direction. The three notch portions C to be formed are configured. Similarly, each notch C located on the end face 25a of the tab laminate 25 and each notch C located on the end face 25b side are connected to each other, and three notches C extending in the Y-axis direction are connected. It is composed.

  FIG. 9 is a view of a part of the electrode assembly in a state after the welded portion W is formed as viewed from the Z-axis direction. In the example shown in FIG. 9, the cutout portion C further includes a third portion C3. The third portion C3 is adjacent to the first portion C1 in the direction from the end faces 21a, 21b, 25a, 25b of the tab laminates 21, 25 to the outside.

  Thus, even when a part of the notch C is located outside the end faces 21a, 21b, 25a, 25b of the tab laminates 21, 25, the molten tab is notched when the weld W is formed. It can be made to flow into part C.

  Here, when the notch C is provided in a portion adjacent to the region R of the current collector plates 16 and 19, the notch C may be covered with the tab laminates 21 and 25. When the notch C is completely covered, it is difficult for air to be discharged from the notch C when the molten tab flows into the notch C, and the molten tab may not easily flow into the notch C. On the other hand, as described above, if a part of the notch C is located outside the end surfaces 21a, 21b, 25a, 25b of the tab laminates 21, 25, a part of the notch C is a tab. Since it exposes without being covered with the laminated bodies 21 and 25, air is reliably discharged | emitted from the part. Therefore, it becomes easy for the molten tab to flow into the notch C.

(Second modification)
Moreover, the length of a notch part may be equal to the length of the part for forming a welding part in the direction which goes inside from the end surface of a tab laminated body. 10 and 11 are views schematically showing a part of the electrode assembly according to such a modification.

  FIG. 10 is a view of a part of the electrode assembly in a state before the weld W is formed, as viewed from the Z-axis direction. In the example shown in FIG. 10, the length of the notch C is equal to the length of the region R in the Y-axis direction.

  FIG. 11 is a view of a part of the electrode assembly in a state after the welded portion W is formed, as viewed from the Z-axis direction. In the example shown in FIG. 11, the notch C is filled with the molten tab.

  Thus, even if the length of the notch C is equal to the length of the region R in the Y-axis direction, the molten tab can flow into the notch C when the weld W is formed. . In this case, it is possible to prevent the length of the cutout portion C from becoming longer than necessary.

(Third Modification)
In the above-described embodiment, the example in which the current collector plates 16 and 19 have the notch C has been described. However, the tab laminates 21 and 25 may have the notch C. 12 and 13 are views schematically showing a part of an electrode assembly according to such a modification.

  FIG. 12 is a diagram schematically showing a part of the electrode assembly in a state before the welded portion W is formed. FIG. 12A is a diagram illustrating a part of the electrode assembly viewed from the Z-axis direction, and FIG. 12B is a diagram illustrating a part of the electrode assembly viewed from the X-axis direction.

  As shown in FIG. 12, the notch C is provided on each of the end faces 21a, 21b, 25a, 25b of the tab laminates 21, 25. The notch C may be formed in advance by processing a part of each tab before the tabs 14b and 17b are stacked on the current collectors 16 and 19, respectively. It may be formed by processing a part of the tab laminates 21 and 25 after the tabs 14b and 17b are respectively laminated thereon. The processing method may be the same as that of the current collector plates 16 and 19 described above. In the example shown in FIG. 12, the notch C is located at the center of the region R in the X-axis direction.

  FIG. 13 is a diagram schematically showing a part of the electrode assembly in a state after the welded portion W is formed. FIG. 13A is a diagram showing a part of the electrode assembly viewed from the Z-axis direction, and FIG. 13B is a diagram showing a part of the electrode assembly viewed from the X-axis direction.

  As shown in FIG. 13, the melted tab flows into the notch C, whereby the first portion C1 is formed. Moreover, the 2nd part C2 is formed as a part into which the fusion | melting tab did not flow among the notch parts C. As shown in FIG.

  Thus, by providing the notch portion C on the end faces 21a, 21b, 25a, and 25b of the tab laminates 21 and 25, the molten tab flows into the notch portion C when the welded portion W is formed. Can be.

(Fourth modification)
Further, the protection plates 23 and 27 may have a notch C. FIG. 14 is a diagram schematically showing a part of the electrode assembly according to such a modification as seen from the X-axis direction. In the example shown in FIG. 14, the protection plates 23 and 27 have a notch C. The notch C is provided in a portion adjacent to the welded portion W (region R) of the protection plates 23 and 27 in the Z-axis direction. For example, by providing the cutout portion C in this way, the molten tab can flow into the cutout portion C when the welded portion W is formed.

  Moreover, in the said embodiment, regarding the shape of the notch part C, the notch part C has a substantially rectangular shape when viewed from the Z-axis direction, and a substantially rectangular cross-sectional shape when viewed from the extending direction (Y-axis direction). An example having the above has been described (FIGS. 4, 5, etc.). However, the shape of the cutout portion C is not particularly limited as long as the melt tab can flow into the cutout portion C. For example, the notch C may have a substantially triangular shape when viewed from the Z-axis direction. In this case, the two adjacent sides of the triangular shape may be spaced apart from each other toward the outside of the tab laminates 21 and 25.

  In addition, although the said embodiment demonstrated the example in which the welding part W was formed in the end surfaces 21a, 21b, 25a, and 25b of the tab laminated bodies 21 and 25, respectively, the position where the welding part W is formed is limited to this. Not. For example, in the tab laminate 21, the welded portion W may be formed only on one of the end surface 21a and the end surface 21b. Similarly, in the tab laminate 25, the welded portion W may be formed only on one of the end surfaces 25a and 25b. In any case, the notch C is a position corresponding to the portion where the welded portion W is formed, that is, the welded portion in the tab laminates 21 and 25 when viewed from the stacking direction of the tab laminates 21 and 25. It suffices if it is located in a portion for forming W.

  A configuration in which the above-described embodiments described above and the characteristic portions of each modification are appropriately combined can also be used as the embodiment of the present invention.

  DESCRIPTION OF SYMBOLS 3 ... Electrode assembly, 11 ... Positive electrode (electrode), 12 ... Negative electrode (electrode), 14b, 17b ... Tab, 16, 19 ... Current collecting plate (conductive member), 21, 25 ... Tab laminated body, 21a, 21b, 25a, 25b ... end face, 23, 27 ... protective plate (conductive member), C ... notch, C1 ... first part, C2 ... second part, W ... welded part.

Claims (8)

A method of manufacturing an electrode assembly having a plurality of electrodes each including a tab,
Preparing a tab laminate having a plurality of the tabs arranged and laminated on the conductive member;
Forming a welded portion on the inner side from the end face of the tab laminate by welding the end face of the tab laminate extending along the lamination direction of the tab laminate; and
Including
In the preparing step, at least one of the conductive member and the tab laminate is a cut located at a portion of the tab laminate for forming the welded portion when viewed from the lamination direction of the tab laminate. A method for manufacturing an electrode assembly having a notch.   The method of manufacturing an electrode assembly according to claim 1, wherein the notch is provided in a portion of the conductive member adjacent to a portion for forming the weld.   The method of manufacturing an electrode assembly according to claim 1, wherein the notch is provided on the end face of the tab laminate. In the step of preparing,
When the tab laminate and the conductive member are viewed from the lamination direction of the tab laminate, a part of the notch is located outside the end surface of the tab laminate.
The manufacturing method of the electrode assembly of Claim 2.   5. The method of manufacturing an electrode assembly according to claim 1, wherein the cutout portion is provided so as to extend in a direction from the end face of the tab laminated body toward the inside. In the step of preparing,
In the direction from the end face of the tab laminate to the inside, the length of the notch is equal to the length of the portion for forming the welded portion,
The manufacturing method of the electrode assembly of any one of Claims 1-5. An electrode assembly having a plurality of electrodes each including a tab,
A conductive member;
A tab laminate having a plurality of the tabs arranged and laminated on the conductive member;
With
The tab laminated body has a weld portion located on the inner side from an end surface of the tab laminated body extending along the lamination direction of the tab laminated body,
At least one of the conductive member and the tab laminate includes a first portion located at the weld when viewed from the lamination direction of the tab laminate, and a direction from the end surface of the tab laminate to the inside. A notch having a second part adjacent to the first part in
The first part is buried with the same material as the material of the weld,
The second part is a void;
Electrode assembly.   The electrode assembly according to claim 7, wherein a tip end of the notch portion is located inside the tip end of the welded portion in a direction from the end face of the tab laminated body toward the inside.

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