JP6103204B2 - Method for manufacturing power storage device - Google Patents

Description

The present invention relates to a method for producing a charge reservoir.

  Power storage devices such as secondary batteries and capacitors are widely used as power sources because they can be recharged and can be used repeatedly. In general, a power storage device with a large capacity includes a case for accommodating an electrode assembly, and the electrode assembly is accommodated in the case. And extraction of the electric power from an electrical storage apparatus is performed through the electrode terminal connected to the positive electrode and negative electrode of an electrode assembly.

  Examples of the electrode assembly include a stacked electrode assembly in which separators are interposed between a plurality of positive electrodes and a plurality of negative electrodes, and a strip-shaped separator between a strip-shaped positive electrode and a strip-shaped negative electrode. There is a wound-type electrode assembly that is wound in a state where a metal is interposed. Each of the positive electrode and the negative electrode has a plurality of metal foil portions called tabs, and the plurality of tabs are electrically connected to the positive electrode terminal or the negative electrode terminal via a conductive member. The plurality of tabs are welded by resistance welding in a state where a plurality of tabs are stacked on the conductive member.

  When a plurality of tabs and a conductive member are joined by resistance welding, spatter is generated during welding. Conventionally, when resistance welding the core (electrode) and current collector (conductive member) of the power generation element (electrode assembly), metal dust generated as spatter is prevented from moving into the electrode assembly. Thus, a highly reliable sealed battery with less occurrence of internal short circuit and a method for manufacturing the same has been proposed (see Patent Document 1).

  As shown in FIGS. 13 and 14, the sealed battery of Patent Document 1 has a plurality of negative electrode tabs (core body exposed portions) at one end in the winding axis direction (left and right direction in FIG. 13) of a wound electrode assembly 61. 62) and a positive electrode tab (not shown) at the other end. The negative electrode tab 62 is joined to the negative electrode conductive member 63 and the negative electrode conductive member receiving component 64 by resistance welding. When welding the negative electrode tab 62, the negative electrode conductive member 63, and the negative electrode conductive member receiving component 64, both sides of the welded portion of the negative electrode tab 62 are interposed via a heat-welding resin tape 65 having an opening 65 a formed at the center. The negative electrode conductive member 63 and the negative electrode conductive member receiving component 64 are brought into contact with each other. The negative electrode conductive member 63 is disposed so that the protrusion 63a of the negative electrode conductive member 63 coincides with the center of the opening 65a of the lower heat-weldable resin tape 65, and closes the opening 65a of the upper heat-weldable resin tape 65. In a state where the receiving part 64 is disposed, resistance welding is performed by passing a current between the negative electrode conductive member 63 and the negative electrode conductive member receiving part 64 by the electrode rods 66a and 66b for a predetermined time.

  When resistance welding is performed in a state where the heat-welding resin tape 65 exists around the portion to be resistance-welded, metal dust generated as spatter is trapped inside the heat-welding resin tape 65, and thus spatter is generated. Metal dust is less scattered outside. The same applies to the case where the positive electrode tab, the positive electrode conductive member, and the positive electrode conductive member receiving component are joined by resistance welding.

JP 2009-32640 A

  In Patent Document 1, when the negative electrode tab 62, the negative electrode conductive member 63, and the negative electrode conductive member receiving part 64 are welded by so-called projection welding, even if spatter is generated, dust generated by the spatter is generated in the electrode assembly. In order to suppress the occurrence of an internal short circuit due to the movement inside, a heat-weldable resin tape 65 for capturing the generated dust is provided. However, the spatter generated between the negative electrode conductive member 63 and the electrode rod 66a or the negative electrode conductive member receiving component 64 and the electrode rod 66b adheres to the outside of the electrode assembly or damages the separator. There is no consideration.

The present invention has been made in view of the above problems, and its purpose is to perform resistance welding in a manufacturing process in a state where a plurality of electrode tabs of an electrode are stacked on a conductive member. it is to provide a method of manufacturing it is possible to Ru charge reservoir to prevent damage by sputtering the electrode assembly is scattered.

A manufacturing method of a power storage device that solves the above problems has a layered structure in which a positive electrode and a negative electrode are insulated, and each of the positive electrode and the negative electrode has a plurality of positive electrode tabs and negative electrode tabs connected to electrode terminals via conductive members. A method of manufacturing a power storage device including an electrically connected electrode assembly, wherein the positive electrode tab and the negative electrode tab are respectively laminated in a resistance welding step of joining the conductive member by resistance welding. The positive electrode tab and the negative electrode tab are collected on one end side in the stacking direction of the positive electrode and the negative electrode in the electrode assembly by a jig located on the base end side of the positive electrode tab and the negative electrode tab, and the electrode assembly is supported from the end face of a state extending in a protruding direction, the jig, the positive electrode tab and the end of the electrode assembly so as not to be exposed to the base end side welded portion of the negative electrode tab They are arranged along, the positive electrode tab and said extending portion at least one side extended in the width direction of the width direction of the negative electrode tab, the positive electrode tab and the lamination direction of the negative electrode tab and the conductive member A folding step of performing resistance welding in a state of being bent so as to stand up to the side away from the workpiece, and folding the extending portion in the standing state after resistance welding so as to cover the welded portion and along the end face of the electrode assembly It has.

  According to this configuration, when resistance welding is performed on the conductive member in a state where a plurality of positive electrode tabs and negative electrode tabs are stacked in the resistance welding process, the bases of the positive electrode tab and the negative electrode tab are scattered from the welded portion of the scattered spatter. The spatter scattered toward the end adheres to the jig. Moreover, the spatter scattered so as to go in the width direction of the positive electrode tab and the negative electrode tab adheres to the shielding portion existing in a standing state on both sides of the welded portion. Therefore, it is possible to prevent the electrode assembly from being damaged by the scattered spatter. After the resistance welding, the shielding portion covers the welded portion from the standing state and is folded along the end surface of the electrode assembly, so that the amount of the shielding portion protruding from the end surface of the electrode assembly is reduced.

  According to the present invention, it is possible to prevent the electrode assembly from being damaged by the scattered spatter when welding a plurality of electrode tabs of the electrode in a state where a plurality of electrode tabs are stacked on the conductive member in the manufacturing process. it can.

The disassembled perspective view which shows the structure of the secondary battery of 1st Embodiment. The perspective view which shows the external appearance of a secondary battery. The disassembled perspective view which shows an electrode assembly typically. Explanatory drawing explaining a mode that a positive electrode tab is bundled. The schematic perspective view which shows the state in which the positive electrode tab was bundled and laminated | stacked on the electrically-conductive member. The schematic diagram which shows the relationship between a positive electrode tab, an electrically-conductive member, and the electrode for resistance welding. (A) is a schematic diagram which shows the state before a shielding part is bent, (b) is a schematic diagram which shows the state by which the shielding part was bent. (A) is a schematic cross-sectional view of a state in which the shielding portion of the positive electrode is bent so as to cover the positive electrode tab after welding, and (b) is a schematic cross-sectional view showing a state in which the positive electrode tab and the conductive member are bent. The front view of the positive electrode of another embodiment. The perspective view which shows typically the electrode assembly of another embodiment. The front view of the positive electrode which has a shielding part on the one side of a tab. The perspective view which shows the external appearance of the electrode assembly of another embodiment. Sectional drawing of a prior art. FIG. 14 is an enlarged exploded view of a portion surrounded by an alternate long and short dash line in FIG. 13.

Hereinafter, an embodiment in which the present invention is embodied in a secondary battery including a stacked electrode assembly will be described with reference to FIGS.
As shown in FIGS. 1 and 2, a secondary battery 10 as a power storage device includes a stacked-type electrode in a rectangular box-shaped case 11 that includes a case body 11 a and a lid 11 b that covers an opening thereof. The assembly 12 and an electrolytic solution (not shown) are accommodated. In the following description, for convenience of explanation, the direction indicated by the arrow X is the left direction, the direction indicated by the arrow Y is the front direction, and the direction indicated by the arrow Z is the upward direction.

  As shown in FIGS. 1 and 3, the electrode assembly 12 includes a plurality of positive electrodes 14 having active material layers 14 a on both surfaces of a metal foil 13 and a plurality of negative electrodes 15 having active material layers 15 a on both surfaces of the metal foil 13. Are laminated with a separator 16 interposed therebetween. In the positive electrode 14 and the negative electrode 15, the portions where the active material layers 14 a and 15 a are formed are formed in a rectangular shape. Each positive electrode 14 is provided with a positive electrode tab 14 b as an electrode tab protruding from the left side of one end surface (the upper end surface in FIGS. 1 and 3) of the electrode assembly 12. The positive electrode tab 14b is formed such that a part of the metal foil 13 protrudes from one end of the active material layer 14a. Each negative electrode 15 is provided with a negative electrode tab 15b as an electrode tab protruding from the right side of one end surface of the electrode assembly 12 (upper end surface in FIGS. 1 and 3). The negative electrode tab 15b is formed so that a part of the metal foil 13 protrudes from one end of the active material layer 15a.

  The separator 16 is formed in a rectangular shape larger than the rectangular portions of the positive electrode 14 and the negative electrode 15 excluding the positive electrode tab 14 b and the negative electrode tab 15 b in order to ensure electrical insulation between the positive electrode 14 and the negative electrode 15. When the secondary battery 10 is a lithium ion secondary battery, the metal foil 13 for the positive electrode 14 is preferably an aluminum foil, and the metal foil 13 for the negative electrode 15 is preferably a copper foil.

  As shown in FIGS. 1 and 2, the case 11 is provided with a positive electrode terminal 21 and a negative electrode terminal 22 as electrode terminals in a state of protruding from the lid 11b. The positive electrode terminal 21 and the negative electrode terminal 22 are provided in a state of penetrating a ring-shaped insulating member 23 attached to a hole 11c formed in the lid 11b. In this embodiment, the positive electrode terminal 21 is formed separately from the positive electrode conductive member 24 as a conductive member, and the negative electrode terminal 22 is formed separately from the negative electrode conductive member 25 as a conductive member. The positive electrode terminal 21 is welded to the positive electrode conductive member 24 via the plate-like connection portion 21a, and the negative electrode terminal 22 is welded to the negative electrode conductive member 25 via the plate-like connection portion 22a.

  As shown in FIG. 1, the positive electrode tab 14b is electrically connected to the positive electrode conductive member 24 in a laminated state by resistance welding. The negative electrode tab 15b is electrically connected to the negative electrode conductive member 25 in a laminated state by resistance welding. That is, the electrode assembly 12 has a layered structure in which the positive electrode 14 and the negative electrode 15 are insulated, and each of the positive electrode 14 and the negative electrode 15 includes a plurality of positive electrode tabs 14b and negative electrode tabs 15b. And the negative electrode conductive member 25) are electrically connected to the electrode terminals (the positive electrode terminal 21 and the negative electrode terminal 22).

  As shown in FIG. 1, the joining structure of the positive electrode tab 14b and the positive electrode conductive member 24 and the joining structure of the negative electrode tab 15b and the negative electrode conductive member 25 are configured symmetrically. The positive electrode conductive member 24 is resistance-welded to the positive electrode tab 14 b at an upright portion 24 a extending in the vertical direction on the front side of the electrode assembly 12. The negative electrode conductive member 25 is resistance-welded to the negative electrode tab 15b at an upright portion 25a extending in the vertical direction on the front side of the electrode assembly 12.

  The positive electrode conductive member 24 is formed such that the width of the portion above the upright portion 24 a is larger on the left side of the upright portion 24 a, and the wide portion 24 b extends along the upper end surface of the electrode assembly 12. It is bent toward the rear side. The positive electrode conductive member 24 is welded to the connection portion 21a of the positive electrode terminal 21 at the wide portion 24b.

  The negative electrode conductive member 25 is formed such that the width of the portion above the upright portion 25a is larger on the right side of the upright portion 25a, and the wide portion 25b extends along the upper end surface of the electrode assembly 12. It is bent toward the rear side. The negative electrode conductive member 25 is welded to the connection portion 22a of the negative electrode terminal 22 at the wide portion 25b.

  As shown in FIG. 3, the positive electrode tab 14 b of the positive electrode 14 disposed on the foremost side of the electrode assembly 12 is sputtered in a direction intersecting with the direction in which the positive electrode tab 14 b extends during resistance welding to the positive electrode conductive member 24. The shielding part 14c which plays the role which prevents scattering is provided. The negative electrode tab 15b of the negative electrode 15 arranged on the foremost side of the electrode assembly 12 plays a role of preventing spatter scattering in a direction crossing the extending direction of the negative electrode tab 15b during resistance welding to the negative electrode conductive member 25. A shielding part 15c is provided. The shielding portions 14c and 15c are provided on both sides of the positive electrode tab 14b and the negative electrode tab 15b in the width direction, respectively. The shielding portions 14c and 15c are provided over substantially the entire length of the positive electrode tab 14b and the negative electrode tab 15b, respectively. The shielding portions 14c and 15c are formed as extending portions obtained by extending a part of the positive electrode tab 14b or the negative electrode tab 15b in the width direction.

  As shown in FIG. 1, the positive electrode tab 14b and the negative electrode tab 15b have the shielding portions 14c and 15c covering the welded portions and folded so as to overlap the positive electrode tab 14b or the negative electrode tab 15b. It is bent along the positive electrode conductive member 24 or the negative electrode conductive member 25 below the negative electrode conductive member 25.

  Next, a resistance welding process for joining the positive electrode tab 14b and the negative electrode tab 15b to the conductive members (the positive electrode conductive member 24 and the negative electrode conductive member 25) will be described. Since the bonding structure of the positive electrode tab 14b and the positive electrode conductive member 24 and the bonding structure of the negative electrode tab 15b and the negative electrode conductive member 25 are configured symmetrically, the welding process of the positive electrode conductive member 24 and the positive electrode tab 14b is as follows. The welding process of the negative electrode conductive member 25 and the negative electrode tab 15b is basically performed in the same manner. For the convenience of illustration, a welding process between the positive electrode conductive member 24 and the positive electrode tab 14b will be described.

  In the welding process, as shown in FIGS. 4 and 5, the positive electrode tab 14b located at the foremost part of the electrode assembly 12 is in the lower side, and the portion near the base end of the positive electrode tab 14b is the positive electrode conductive material. The electrode assembly 12 is disposed on the support base 30 in a state where the electrode assembly 12 is positioned on a portion to be a welding portion of the member 24. In this state, the other positive electrode tabs 14b are gathered on the positive electrode conductive member 24 from the upper side in the stacking direction of the electrode assembly 12 toward the lower side. Specifically, the uppermost positive electrode tab 14b is collected in a state of being in contact with the jig 31 (shown in FIG. 5).

  As shown in FIG. 5, the positive electrode conductive member 24 is arranged in a state before the wide portion 24 b continuous with the standing portion 24 a is bent. The shielding portion 14c formed integrally with the positive electrode tab 14b arranged in contact with the positive electrode conductive member 24 is arranged in a state of being located with each positive electrode tab 14b interposed therebetween.

  Next, as shown in FIG. 6, the welding electrodes 32 and 33 are arranged with the positive electrode tab 14b and the positive electrode conductive member 24 interposed therebetween, and one welding electrode 32 abuts on the positive electrode conductive member 24 and the other welding electrode. 33 abuts on the uppermost stacked positive electrode tab 14b. FIG. 7A schematically shows the relationship between the positive electrode tab 14b, the positive electrode conductive member 24, and the welding electrodes 32 and 33 in this state. Next, as shown in FIG. 7B, the shielding portion 15c of the positive electrode tab 14b is bent upward.

  Next, when a voltage is applied in a state in which the welding electrodes 32 and 33 press the positive electrode tab 14b and the positive electrode conductive member 24, the positive electrode tab 14b and the positive electrode conductive member 24 are melted at the portion that becomes the welded portion 26 and resists. Welded. During resistance welding, since the jig 31 is positioned on the base end side of the positive electrode tab 14 b, spatter scattered in the direction of the jig 31 among the spatters generated during resistance welding adheres to the jig 31. If the spatter scattered in the width direction of the positive electrode tab 14 b does not have the shielding portion 14 c, a part of the spatter adheres to the outside of the electrode assembly 12 or damages the separator 16. However, when the shielding part 14c exists, since the spatter scattered in the width direction of the positive electrode tab 14b adheres to the shielding part 14c, a part of the scattered spatter adheres to the outside of the electrode assembly 12, or the separator 16 Is prevented from being damaged.

  As shown in FIG. 8A, after the welding of the positive electrode tab 14b and the positive electrode conductive member 24 is finished, the shielding portion 14c of the positive electrode tab 14b is first folded so as to cover each positive electrode tab 14b and overlapped with the positive electrode tab 14b. It will be in the state. Next, as shown in FIG. 8B, the portion of the positive electrode tab 14b on the tip side of the welded portion 26 is bent along the end surface of the electrode assembly 12 together with the shielding portion 14c. Next, the positive electrode conductive member 24 is bent so that the portion on the tip side from the welded portion 26 extends along the upper end surface of the electrode assembly 12, and the state shown in FIGS. 1 and 8B is obtained.

  Since the jig 31 is repeatedly used, the spatter attached to the jig 31 during resistance welding is appropriately removed. Even if the jig 31 is provided with a shielding part for receiving the spatter scattered in the width direction of the positive electrode tab 14b without providing the shielding part 14c on the positive electrode 14, the spatter adheres to the outside of the electrode assembly 12 or the separator 16 is attached. It can be prevented from being damaged. However, in that case, it is necessary to remove the spatter adhering to the shielding portion provided on the jig 31, and the man-hour for the spatter removal work increases. On the other hand, it is not necessary to remove the spatter adhering to the shielding part 14c of the positive electrode 14. It is not necessary to remove spatter adhering to the shielding portion 15c of the negative electrode 15.

According to this embodiment, the following effects can be obtained.
(1) The secondary battery 10 (power storage device) has a layered structure in which the positive electrode 14 and the negative electrode 15 are insulated. The electrode assembly 12 is electrically connected to the electrode terminals (the positive terminal 21 and the negative terminal 22) through the member 24 and the negative electrode conductive member 25. At least one of the positive electrode tab 14b and the negative electrode tab 15b is joined to the conductive member by resistance welding in a stacked state, and the resistance welded tab is at least one of the welding positions of the conductive member and the tab in the tab width direction. It has an extension part extended from the part laminated | stacked on the side of this, and the extension part is provided in the state folded so that the welding location might be covered. Therefore, in the manufacturing process, a plurality of electrode tabs (positive electrode tab 14b and negative electrode tab 15b) of the electrodes (positive electrode 14 and negative electrode 15) are laminated on the conductive members (positive electrode conductive member 24 and negative electrode conductive member 25). When welding is performed in this state, the electrode assembly 12 can be prevented from being damaged by the scattered spatter.

  (2) The extending portions are shielding portions 14c and 15c that prevent spatter scattering in the direction intersecting with the extending direction of the positive electrode tab 14b and the negative electrode tab 15b during resistance welding to the conductive member. In this configuration, in the manufacturing process, when resistance welding is performed in a state where a plurality of electrode tabs of the electrode are stacked on the conductive member, the extending portion tends to scatter in a direction intersecting with the extending direction of the electrode tab. This prevents the spatter from being damaged and prevents the electrode assembly 12 from being damaged by the spatter.

  (3) The shielding portions 14c and 15c are provided on both sides of the positive electrode tab 14b and the negative electrode tab 15b in the width direction. If the protruding positions of the positive electrode tab 14b and the negative electrode tab 15b from the positive electrode 14 and the negative electrode 15 are the end portions of the electrode assembly 12, the shielding portions 14c and 15c are provided on one side of the welded portion, so that the electrode assembly 12 is scattered. It is possible to prevent damage caused by spattering. However, in general, the positive electrode tab 14 b and the negative electrode tab 15 b are formed not at the end portion of the electrode assembly 12 but at a distance from the end portion. When the shielding portions 14c and 15c are provided on both sides in the width direction of the positive electrode tab 14b and the negative electrode tab 15b, it corresponds regardless of the protruding positions of the positive electrode tab 14b and the negative electrode tab 15b from the electrodes (the positive electrode 14 and the negative electrode 15). can do.

  (4) The shielding portions 14c and 15c are provided on each of the positive electrode tab 14b and the negative electrode tab 15b. The shielding portions 14c and 15c have a shielding effect with the thickness of one positive electrode tab 14b or negative electrode tab 15b, and when the shielding portions 14c and 15c are provided on one positive electrode tab 14b and one negative electrode tab 15b, respectively. Compared with the case where the positive electrode tab and the negative electrode tab are provided, the folding work after resistance welding is facilitated. Further, when the shielding portions 14c and 15c are provided on the single positive electrode tab 14b and the negative electrode tab 15b, respectively, the weight of the shielding portions 14c and 15c is reduced, and the energy density per weight of the secondary battery 10 is increased. .

  (5) The manufacturing method of the secondary battery 10 includes a positive electrode tab 14b and a negative electrode tab in a resistance welding process in which the positive electrode tab 14b and the negative electrode tab 15b are joined to the positive electrode conductive member 24 and the negative electrode conductive member 25 by resistance welding. 15b is supported by a jig 31 positioned on the base end side so as to extend in a direction protruding from the end face of the electrode assembly 12 in a stacked state. The shielding portions 14c, 15c provided on at least one side in the width direction of the positive electrode tab 14b and the negative electrode tab 15b are arranged in the stacking direction of the positive electrode tab 14b and the negative electrode tab 15b, and the positive electrode conductive member 24 and the negative electrode conductive member. Resistance welding is performed in a state of being bent so as to stand on the side away from 25. Therefore, in the manufacturing process, a plurality of electrode tabs (14b and negative electrode tab 15b) of the electrodes (positive electrode 14 and negative electrode 15) were laminated on the conductive members (positive electrode conductive member 24 and negative electrode conductive member 25). When welding in a state, it is possible to prevent the electrode assembly 12 from being damaged by the scattered spatter.

  (6) The method for manufacturing the secondary battery 10 includes a folding step of folding the shield portions 14c and 15c in the standing state after resistance welding so as to cover the welded portion 26 and follow the end surface of the electrode assembly 12. . Therefore, the amount of the shielding portions 14c and 15c protruding from the end surface of the electrode assembly 12 is smaller than that in the case where the standing shielding portions 14c and 15c are not folded after resistance welding. The volume can be reduced, and the energy density per volume of the secondary battery 10 is increased.

  (6) When the shielding portion 14c and the shielding portion 15c are joined to the positive electrode conductive member 24 and the negative electrode conductive member 25 in a state where the positive electrode tab 14b and the negative electrode tab 15b are stacked, respectively, The positive electrode tab 14 b and the negative electrode tab 15 b are in contact with the conductive member 24 and the negative electrode conductive member 25. Therefore, it is possible to shield spatter generated and scattered at any location of the positive electrode tab 14b and the negative electrode tab 15b that are resistance-welded in a state of being laminated on the positive electrode conductive member 24 and the negative electrode conductive member 25.

The embodiment is not limited to the above, and may be embodied as follows, for example.
As shown in FIG. 9, the positive electrode 14 has a region 14 d where the active material layer 14 a is not formed between the upper edge of the active material layer 14 a and the upper edge of the metal foil 13, and continues to the region 14 d. The structure in which the positive electrode tab 14b was formed may be sufficient. Similarly, in the negative electrode 15, there is a region where the active material layer 15 a is not formed between the upper edge of the active material layer 15 a and the upper edge of the metal foil 13, and the negative electrode tab 15 b is formed continuously in that region. It may be configured.

  As shown in FIG. 9, the positive electrode 14 may have a configuration in which the shielding portion 14 c is provided in part of the positive electrode tab 14 b instead of the full length. The shielding part 14c only needs to shield the spatter generated during resistance welding and passing through the widthwise end of the positive electrode tab 14b and proceeding toward the electrode assembly 12, and the function of shielding other spatters is as follows. Since it does not have to be present, it only has to exist at that location. Similarly, the negative electrode 15 may have a configuration in which the shielding portion 15c is provided in part of the negative electrode tab 15b instead of the entire length.

As shown in FIG. 10, the protruding positions of the positive electrode tab 14 b and the negative electrode tab 15 b from the positive electrode 14 and the negative electrode 15 may be the left end portion and the right end portion of the electrode assembly 12.
○ When the protruding positions of the electrode tabs (the positive electrode tab 14b and the negative electrode tab 15b) from the electrodes (the positive electrode 14 and the negative electrode 15) are the end portions of the electrode assembly 12, the shielding portions 14c and 15c are provided on both sides of the electrode tab in the width direction. There is no need to provide it. For example, when the positive electrode tab 14b is provided at the left end portion of the electrode assembly 12, as shown in FIG. 11, the positive electrode 14 has a positive electrode tab 14b projecting from the left end of the upper edge and a shielding portion on the right side of the positive electrode tab 14b. 14c is formed. In this case, although not shown, the negative electrode 15 has a negative electrode tab 15b protruding at the right end of the upper edge, and a shielding part 15c is formed on the left side of the negative electrode tab 15b.

  The present invention is not limited to the stacked electrode assembly 12 and may be applied to the secondary battery 10 including a wound electrode assembly. For example, as shown in FIG. 12, in the electrode assembly 40, the positive electrode tab 41 and the negative electrode tab 42 are respectively rotationally symmetric with respect to the winding center on the end surface on one end side in the winding axis direction of the electrode assembly 12. Projected to The positive electrode tab 41 and the negative electrode tab 42 are formed with shielding portions 41a and 42a, respectively. The positive electrode conductive member 43 and the negative electrode conductive member 44 are in contact with the positive electrode tab 41 and the negative electrode tab 42 located on the outermost peripheral side of the wound portion of the electrode among the stacked positive electrode tab 41 and negative electrode tab 42. It is welded and provided so as to extend in the axial direction of the electrode assembly 40. FIG. 12 shows a state where the shield portions 41 a and 42 a are not bent after resistance welding, and the shield portions 41 a and 42 a are bent so as to extend along the left-right direction of the electrode assembly 12.

  The shielding portions 14c, 15c, 41a, 42a are provided on the positive electrode tabs 14b, 41 or the negative electrode tabs 15b, 42 in contact with the positive electrode conductive members 24, 43 and the negative electrode conductive members 25, 44, respectively. However, the present invention is not limited to this, and it may be provided on either of the stacked positive electrode tabs 14b and 41 or negative electrode tabs 15b and 42, respectively.

  Each of the two shielding portions 14c, 15c, 41a, 42a is not limited to the configuration provided on the same positive electrode tab 14b, 41 or negative electrode tab 15b, 42, but is different from the positive electrode tab 14b, 41 or negative electrode tab. One piece may be provided on each of the different sides of 15b and 42.

  ○ Two or more shielding portions 14c, 15c, 41a, 42a may be provided on each side of the positive electrode tabs 14b, 41 or the negative electrode tabs 15b, 42, for example, all the positive electrode tabs 14b, 41 and the negative electrode tabs 15b. , 42 may be provided on both sides in the width direction. However, the folding operation after resistance welding becomes easier in the configuration in which the number of the shielding portions 14c, 15c, 41a, and 42a is small.

  The electrode assembly 12 has a structure in which the bonding structure of the positive electrode tab 14b and the positive electrode conductive member 24 and the bonding structure of the negative electrode tab 15b and the negative electrode conductive member 25 are arranged in a rotationally symmetric state instead of left-right symmetry. Also good.

  The positive electrode 14 and the negative electrode 15 are not limited to a structure in which the active material is applied to the metal foil 13 to form the active material layers 14a and 15a. For example, the positive electrode 14 or the negative electrode 15 of the stacked electrode assembly 12 is formed by filling a hole in a three-dimensional metal porous body having a plurality of holes as a current collector to form an active material layer. In addition, the electrode tab may be formed at a portion where the porous portion at one end of the metal porous body is crushed into a plate shape.

As the active material layers 14a and 15a of the positive electrode 14 or the negative electrode 15 of the stacked electrode assembly 12, a material obtained by shaping an active material into a plate shape may be used.
In place of the metal foil 13 that holds the active material layers 14a and 15a of the positive electrode 14 and the negative electrode 15, a mesh-like metal sheet may be used.

  ○ The positive electrode tab 14b and the negative electrode tab 15b are not limited to a structure formed by protruding a part of the metal foil 13, and another metal foil is bonded to a portion of the metal foil 13 that supports (holds) the active material layer. May be formed.

  ○ Instead of integrally forming the shielding parts 14c, 41a, 15c, 42a with the positive electrode tabs 14b, 41 or the negative electrode tabs 15b, 42, the shielding parts 14c, 41a, 15c, 42a formed of metal foil are used as the positive electrode tabs 14b, 41 or It may be welded to the negative electrode tabs 15b and 42, or may be joined with a conductive adhesive.

  The positive electrode terminal 21 and the negative electrode terminal 22 are not limited to the configuration in which the positive electrode conductive member 24 or the negative electrode conductive member 25 is joined to the positive electrode conductive member 24 or the negative electrode conductive member 25 via the connection portions 21a and 22a. For example, the positive electrode terminal 21 and the negative electrode terminal 22 may be directly welded to the positive electrode conductive member 24 or the negative electrode conductive member 25, or may be joined by a conductive adhesive or the like.

In the stacked electrode assembly 12, the positive electrode tab 14 b and the negative electrode tab 15 b may protrude from different end surfaces of the electrode assembly 12.
○ After resistance welding, the shields 14c, 15c, 41a, 42a are cut and removed instead of folding the shields 14c, 15c, 41a, 42a so that the electrode assemblies 12, 40 can be accommodated in the case 11 in a compact state. May be. Further, the electrode assemblies 12 and 40 may be accommodated in the case 11 without bending or removing the shielding portions 14c, 15c, 41a, and 42a.

A structure in which at least one of the positive electrode tab 14b and the negative electrode tab 15b is joined to the conductive member by resistance welding in a stacked state may be used.
The secondary battery 10 is not limited to a lithium ion secondary battery, and may be another secondary battery such as a nickel hydrogen secondary battery or a nickel cadmium secondary battery.

The secondary battery 10 does not require an electrolytic solution, and for example, the separator 16 may be formed of a polymer electrolyte.
The power storage device is not limited to the secondary battery 10 and may be a capacitor such as an electric double layer capacitor or a lithium ion capacitor.

The following technical idea (invention) can be understood from the embodiment.
(1) A secondary battery comprising the configuration of the power storage device according to any one of claims 1 to 4.

  DESCRIPTION OF SYMBOLS 10 ... Secondary battery as an electrical storage device, 12, 40 ... Electrode assembly, 14 ... Positive electrode, 14b, 41 ... Positive electrode tab, 14c, 15c, 41a, 42a ... Shielding part, 15 ... Negative electrode, 15b, 42 ... Negative electrode tab , 21... Positive electrode terminal as electrode terminal, 22... Negative electrode terminal as electrode terminal, 26.

Claims (1)

An electricity storage comprising a layered structure in which a positive electrode and a negative electrode are insulated, and each of the positive electrode and the negative electrode includes an electrode assembly in which a plurality of positive electrode tabs and negative electrode tabs are electrically connected to electrode terminals via conductive members. A device manufacturing method comprising:
In the resistance welding process in which the positive electrode tab and the negative electrode tab are laminated and joined to the conductive member by resistance welding, the positive electrode tab and the negative electrode tab are on the proximal end side of the positive electrode tab and the negative electrode tab. By the jig positioned, it is collected on one end side in the stacking direction of the positive electrode and the negative electrode in the electrode assembly, and is supported in a state extending in a direction protruding from the end surface of the electrode assembly ,
The jig is disposed along the end surface of the electrode assembly so that the base end sides of the positive electrode tab and the negative electrode tab are not exposed to the welded portion.
An extending portion extending in the width direction of at least one side of the positive electrode tab and the negative electrode tab in the width direction is erected in the stacking direction of the positive electrode tab and the negative electrode tab and away from the conductive member. Perform resistance welding in the folded state,
A method for manufacturing a power storage device, comprising: a folding step of folding the extending portion in a standing state after resistance welding so as to cover a welding portion and to follow the end face of the electrode assembly.