JP6274013B2 - Power storage device - Google Patents

Description

  The present invention relates to a power storage device, and more particularly to a power storage device characterized by a joint structure between a tab and a conductive member.

  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 having 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.

  As the electrode assembly, for example, there is a stacked electrode assembly in which separators are interposed between a plurality of positive electrodes and a plurality of negative electrodes. Each of the positive electrode and the negative electrode has a plurality of metal foil portions called tabs, and the plurality of tabs are welded in a state of being stacked on the positive electrode terminal or the negative electrode terminal via a conductive member (lead).

  In the configuration in which the tab is electrically connected to the positive electrode terminal and the negative electrode terminal via the conductive member in a state orthogonal to the stacking direction of the electrode assembly, the dead space in the direction intersecting with the stacking direction of the electrode assembly becomes large. 2. Description of the Related Art Conventionally, a power storage device has been proposed that can reduce dead space in a direction that intersects the stacking direction of electrode assemblies and that can prevent damage to the tab when the conductive member is attached to the tab (patent) Reference 1). As shown in FIG. 11, this power storage device welds a plate-like positive electrode lead 70 to a laminated positive electrode tab 71, bends the positive electrode lead 70 together with the front end side 72 of the positive electrode tab 71, and the front end side 72 is positive electrode lead. 70 is housed inside. The positive electrode lead 70 includes an accommodating portion 74 that accommodates the folded portion 73 of the positive electrode tab 71, and a protective portion 76 that curves with the proximal end 75 of the positive electrode tab 71 protruding. Although not shown, the negative electrode lead and the negative electrode tab are also welded in the same structure.

JP 2013-161757 A

  However, in the configuration of Patent Document 1, the storage portion 74 that stores the bent portion on the distal end side of the stacked tab group is bent at the distal end side of the leads, and the proximal end side is convex toward the proximal end side of the tab. Since the curved protective portion 76 is formed, it takes time to fold the lead. Further, an extra space is required for the presence of the protection unit 76.

  The present invention has been made in view of the above problems, and the object thereof is to reduce the amount of protrusion of a lead or tab from the end face of the electrode assembly, thereby eliminating the need for bending the lead. An object of the present invention is to provide a power storage device that can be used.

  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 the positive electrode and the negative electrode are respectively connected to an electrode terminal through a conductive member in a stacked state of a plurality of positive electrode tabs and negative electrode tabs. It is an electrical storage apparatus provided with the electrode assembly electrically connected. And the said positive electrode tab and the said negative electrode tab are each laminated | stacked so that a front-end | tip part may form an inclined surface, and it is welded in the base end side in the state pinched | interposed into the said electrically-conductive member and the protective plate from the lamination direction. The positive electrode tab and the negative electrode tab are housed between the conductive member and the protective plate in a state in which the tip side is bent. Here, “so that the tip portion forms an inclined surface” means that the tip portion of each positive electrode tab or the tip portion of each negative electrode tab exists on a virtual inclined surface.

  According to this configuration, even when the length of the positive electrode tab or the negative electrode tab is increased in order to ensure a sufficient contact area with the conductive member, there is a possibility that the tip portion protrudes from the conductive member and contacts the inner surface of the case. Absent. Further, it is not necessary to bend the conductive member when bending the positive electrode tab or the negative electrode tab. In addition, there is no need to provide an extra space between the end face of the electrode assembly and the positive electrode tab or the negative electrode tab because there is no curved portion (protective portion) forming a part of the conductive member. Accordingly, the amount of protrusion of the lead and tab from the end face of the electrode assembly can be reduced, and the bending of the lead can be eliminated.

  It is preferable that the bent portion of the positive electrode tab and the negative electrode tab is on the tip side from half of the inclined surface portion. According to this configuration, since the total thickness of the portion where the folded portions on the distal end side of the laminated tab group are overlapped can be less than the thickness on the proximal end side of the laminated tab group, the protective plate Even if a flat plate is used instead of the stepped plate, the bent portion on the tip side of the laminated tab group can be stored between the conductive member and the protective plate.

The protective plate is preferably a flat plate. The protection plate may be a stepped plate, but the flat plate is easier to manufacture.
The bent portion of the positive electrode tab and the negative electrode tab is preferably closer to the root side than half of the inclined surface portion. According to this configuration, the length of the electrode assembly in the thickness direction (electrode stacking direction) of the conductive member and the protective plate is shortened as compared with the case where the bent portion is on the tip side from half of the inclined surface portion. Can do.

  The protective plate is preferably a stepped plate. When the bent portion of the positive electrode tab and the negative electrode tab is on the base side from half of the inclined surface portion, the bent positive electrode tab or the tip side portion of the negative electrode tab is stored between the conductive member and the protective plate. It is necessary to provide a step on either the protective plate or the conductive member. In that case, since the protective plate is thinner than the conductive member, it is easier to use the stepped plate as the protective plate than the stepped conductive member.

  According to the present invention, the amount of protrusion of a lead or tab from the end face of the electrode assembly can be reduced, and the bending of the lead can be made unnecessary.

The disassembled perspective view of the secondary battery in 1st Embodiment. Sectional drawing of a secondary battery. The disassembled perspective view which shows the component of an electrode assembly. The fragmentary sectional view of the secondary battery which shows the joining structure of a tab, a protection board, and a lead. The fragmentary sectional view which shows the joining structure of a tab, a protection board, and a lead. (A), (b), (c) is a schematic diagram which shows the welding, bending procedure of a tab, a protective plate, and a lead. (A), (b), (c) is a schematic diagram which shows the welding, bending procedure of the tab in a 2nd Embodiment, a protection board, and a lead | read | reed. (A), (b), (c) is a schematic diagram which shows the welding, bending procedure of the tab of another embodiment, a protection board, and a lead | read | reed. (A), (b), (c) is a schematic diagram which shows the welding, bending procedure of the tab of another embodiment, a protection board, and a lead | read | reed. (A) The schematic diagram of another embodiment, (b) is sectional drawing of the secondary battery which has a winding type electrode assembly. Sectional drawing of a prior art.

(First embodiment)
Hereinafter, a first 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 is provided in a rectangular box-shaped case 11 composed of a bottomed box-shaped case body 11a and a lid 11b covering the opening. The stacked electrode assembly 12 and an electrolytic solution (not shown) are accommodated.

  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 protruding from the left side of one end surface (the upper end surface in FIGS. 1 and 2) 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 projecting from the right side of one end surface of the electrode assembly 12 (upper end surface in FIGS. 1 and 2). 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 FIG. 2, when the electrode assembly 12 is housed in the case 11, the positive electrode terminal 21 and the negative electrode terminal 22 as electrode terminals are formed so as to protrude from the lid body 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. An insulating sheet 11d is attached to the inner surface of the case body 11a and the inner surface of the lid body 11b.

  As shown in FIG. 1, the positive electrode tab 14 b and the negative electrode tab 15 b are welded to the positive electrode conductive member 24 and the negative electrode conductive member 25 in a state where the distal end side is bent along the upper end surface of the electrode assembly 12. Has been.

  Next, the joining structure of the positive electrode tab 14b and the positive electrode conductive member 24 and the negative electrode tab 15b and the negative electrode conductive member 25 will be described in detail. The joining structure of the positive electrode tab 14b and the positive electrode conductive member 24 is the same as that of the negative electrode tab 15b and the negative electrode conductive member 25. explain.

  As shown in FIG. 4, the positive electrode tabs 14b are stacked so that all the positive electrode tabs 14b are gathered toward the positive electrode tabs 14b located on one end side (left end side in FIG. 4) of the tab group and are in contact with each other. Thus, the positive electrode conductive member 24 and the protective plate 26 are welded in a state where the portion facing the positive electrode conductive member 24 extends along the end surface of the electrode assembly 12. Each positive electrode tab 14 b is welded at the welded portion 27 in a state of being sandwiched between the positive electrode conductive member 24 and the protective plate 26 from the stacking direction. The positive electrode conductive member 24 and the protective plate 26 are made of the same material as the positive electrode tab 14b. In the case of the joining structure of the negative electrode tab 15b, the negative electrode conductive member 25 and the protection plate 26 are made of the same material as the negative electrode tab 15b. The number of positive electrode tabs 14b is actually about several tens, but five are illustrated and described for convenience.

  The protective plate 26 is a stepped plate having a length in the thickness direction of the electrode assembly 12 (stacking direction of the positive electrode 14) substantially the same as that of the positive electrode conductive member 24 and having a stepped portion 26a at a substantially intermediate portion. It is formed with. The positive electrode tab 14 b of the positive electrode tab 14 b that protrudes from the positive electrode conductive member 24 is bent at the front end side and is stored between the positive electrode conductive member 24 and the protective plate 26. The protective plate 26 is thinner than the positive electrode conductive member 24. For example, the thickness of the positive electrode conductive member 24 is 1.5 mm, and the thickness of the protective plate 26 is 0.5 mm. In this embodiment, the bent portion of the stacked positive electrode tabs 14b has an inclined surface 17 (see FIG. 5) formed by the tip of each positive electrode tab 14b in the state before the positive electrode tabs 14b are bent (the state shown in FIG. 5). 5 (shown by a two-dot chain line in FIG. 5).

Next, an example of the procedure for forming the above-described joint structure will be described.
When welding the positive electrode tab 14b, the positive electrode conductive member 24, and the protective plate 26, first, as shown in FIG. 5, the positive electrode tab 14b is connected to one end side of the tab group (the left end side in FIG. 5). ) Are collected toward the positive electrode tab 14b side. In this state, the positions of the tips of the positive electrode tabs 14b do not coincide with each other, and the tips are stepped in order, that is, the tips form the inclined surface 17.

  Next, the positive electrode conductive member 24 is arranged in a state where the base end side of the laminated portion 19 of the positive electrode tab 14b and the base end side of the positive electrode conductive member 24 substantially coincide with each other, and the positive electrode tab 14b and the positive electrode tab 14b and The positive electrode conductive member 24 is supported.

  Next, the front end side of the positive electrode tab 14b protruding from the positive electrode conductive member 24 is bent in the direction indicated by the arrow in FIG. 6A, and the protective plate 26 is overlaid on the stacked portion 19 of the positive electrode tab 14b. As a result, the positive electrode tab 14b whose tip portion protruded from the positive electrode conductive member 24 is bent so that the tip portion is located inside the protective plate 26 as shown in FIG. The leading end of the tab 14b is housed between the positive electrode conductive member 24 and the protective plate 26.

  Next, the positive electrode tab 14b, the positive electrode conductive member 24, and the protective plate 26 are welded by resistance welding, and are in a state of being welded at the welded portion 27 as shown in FIG. 6C. Next, the positive electrode tab 14b is bent at the base end side from the portion sandwiched between the positive electrode conductive member 24 and the protective plate 26 so that the positive electrode conductive member 24 and the protective plate 26 are parallel to the end face of the electrode assembly 12. Then, the state shown in FIG. 4 is obtained, and the joining structure of the positive electrode tab 14b, the positive electrode conductive member 24, and the protective plate 26 is completed. 6A to 6C schematically show the electrode assembly 12 and the stacked positive electrode tab 14b.

Next, the operation of the secondary battery 10 configured as described above will be described.
The positive electrode tab 14 b is welded in a state of being sandwiched between the positive electrode conductive member 24 and the protective plate 26, and the tip portion is accommodated between the positive electrode conductive member 24 and the protective plate 26. Therefore, in order to ensure a sufficient contact area with the positive electrode conductive member 24 and the negative electrode conductive member 25, even when the positive electrode tab 14b and the negative electrode tab 15b are lengthened, the positive electrode conductive member 24 or the negative electrode conductive member is used. There is no possibility that the tip portion protruding from the member 25 contacts the inner surface of the case main body 11a. Further, it is not necessary to bend the positive electrode conductive member 24 or the negative electrode conductive member 25 when the positive electrode tab 14b or the negative electrode tab 15b is bent. Further, since there is no curved portion (protective portion) that forms part of the conductive member as in Patent Document 1 between the end face of the electrode assembly 12 and the positive electrode tab 14b or the negative electrode tab 15b, an extra space is provided. There is no need to provide it.

According to this embodiment, the following effects can be obtained.
(1) The secondary battery 10 as a power storage device has a layered structure in which the positive electrode 14 and the negative electrode 15 are insulated, and the positive electrode 14 and the negative electrode 15 each have a plurality of positive electrode tabs 14b and negative electrode tabs 15b stacked. The power storage device includes the electrode assembly 12 electrically connected to the electrode terminals (the positive electrode terminal 21 and the negative electrode terminal 22) through the conductive members (the positive electrode conductive member 24 and the negative electrode conductive member 25). And the positive electrode tab 14b and the negative electrode tab 15b are laminated | stacked so that the front-end | tip part may form the inclined surface 17, and are welded in the base end side in the state pinched | interposed into the conductive member and the protective plate 26 from the lamination direction. The positive electrode tab 14b and the negative electrode tab 15b are housed between the conductive member and the protective plate 26 in a state in which the front end side is bent. Therefore, the amount of protrusion of the leads and tabs from the end face of the electrode assembly 12 can be reduced, and the bending of the leads can be eliminated.

  (2) The bent portion of the positive electrode tab 14b and the negative electrode tab 15b is on the base side from half of the portion of the inclined surface 17 formed by each positive electrode tab 14b or the tip of each negative electrode tab 15b. According to this configuration, the thickness direction of the electrode assembly 12 of the positive electrode conductive member 24, the negative electrode conductive member 25, and the protection plate 26 (as compared to the case where the bent portion is on the tip side from the half of the inclined surface 17 portion ( The length in the electrode stacking direction) can be shortened.

  (3) The protection plate 26 is a stepped plate. When the bent portion of the positive electrode tab 14b and the negative electrode tab 15b is on the base side from the half of the inclined surface 17, the bent positive electrode tab 14b or the tip side portion of the negative electrode tab 15b is used as the positive electrode conductive member 24 or the negative electrode In order to store between the conductive member 25 and the protective plate 26, it is necessary to provide a stepped portion on either the protective plate 26 or the conductive member. In that case, since the protective plate 26 is thinner than the conductive member, it is easier to use the stepped plate as the protective plate 26 than the stepped conductive member.

  (4) In the case of the bonding structure of the positive electrode tab 14b, the positive electrode conductive member 24 and the protective plate 26 are made of the same material as the positive electrode tab 14b. In the case of the bonding structure of the negative electrode tab 15b, the negative electrode conductive member 25 and the protective plate 26. Is the same material as the negative electrode tab 15b. Therefore, electrolytic corrosion is prevented.

(Second Embodiment)
Next, a second embodiment of the present invention will be described with reference to FIGS. In addition, since 2nd Embodiment is the structure which changed the formation procedure of the joining structure of the tab of 1st Embodiment, and a conductive member, the detailed description is abbreviate | omitted about the same part.

  In this embodiment, as a procedure for forming the joint structure between the tab and the conductive member, the tab laminated portion 19 is turned into a conductive member (positive electrode conductive member 24 or negative electrode conductive member 25) before the front end side of the laminated tab group is bent. The first embodiment is different from the first embodiment in that the tab is folded between the conductive member and the protective plate 26 after being welded in a state of being sandwiched between the protective plate 26 and the protective plate 26.

  The joining structure of the positive electrode tab 14b and the positive electrode conductive member 24 will be described as an example. First, all the positive electrode tabs 14b are gathered toward the positive electrode tab 14b side located at one end side of the tab group, and the tip of each positive electrode tab 14b is collected. In a state where the portions are laminated so as to form an inclined surface, the tab group is welded while being sandwiched between the positive electrode conductive member 24 and the protective plate 26 as shown in FIG. The protection plate 26 is not stepped but uses an L-shaped cross section.

  Next, as shown in FIG. 7B, after the front end side of the laminated tab group is bent, the unwelded side of the L-shaped protection plate 26 is bent so as to be parallel to the positive electrode conductive member 24. . As a result, as shown in FIG. 7 (c), the laminated tab group is in a state in which the bent portion on the tip side of the laminated tab group is accommodated between the positive electrode conductive member 24 and the stepped protective plate 26. Become. In this state, the positive electrode conductive member 24 and the protective plate 26 are parallel to the end face of the electrode assembly 12 on the proximal side from the position where the positive electrode tab 14b is sandwiched between the positive electrode conductive member 24 and the protective plate 26. When bent, the state shown in FIG. 4 of the first embodiment is obtained, and the joining structure of the positive electrode tab 14b, the positive electrode conductive member 24, and the protective plate 26 is completed.

In this embodiment, in addition to the same effects as (1) to (4) in the first embodiment, the following effects can be obtained.
(5) After the laminated group of the positive electrode tabs 14b is sandwiched and welded between the positive electrode conductive member 24 and the protective plate 26, the front end side of the laminated tab group is bent. Therefore, when the front end side of the laminated tab group is bent, the positional relationship among the positive electrode tab 14b, the positive electrode conductive member 24, and the protective plate 26 does not shift.

  (6) The portion of the protective plate 26 that houses the bent leading end side with the positive electrode conductive member 24 is disposed at a position parallel to the positive electrode conductive member 24 when the front end side of the laminated tab group is bent. However, it is arranged so as to be substantially perpendicular to the laminated tab group, and after the front end side of the laminated tab group is bent, it is bent and arranged in a state parallel to the positive electrode conductive member 24. Therefore, the work becomes easier as compared with the case where the leading end side of the laminated tab group is inserted and arranged between the positive electrode conductive member 24 and the protective plate 26 extending in parallel.

The embodiment is not limited to the above, and may be embodied as follows, for example.
As shown in FIG. 8 (a), after holding the tab group of the positive electrode tab 14b so as to be sandwiched between the positive electrode conductive member 24 and the stepped protective plate 26, As shown, the tab group is welded to the positive electrode conductive member 24 and the protective plate 26. After welding, as shown in FIG. 8C, the front end side of the laminated tab group is bent and stored between the positive electrode conductive member 24 and the protective plate 26. Thereafter, the positive electrode tab 14 b is bent so that the positive electrode conductive member 24 and the protective plate 26 are parallel to the end surface of the electrode assembly 12 on the base end side from the portion sandwiched between the positive electrode conductive member 24 and the protective plate 26. May be. The same applies to the negative electrode tab 15b.

  As shown in FIG. 9A, first, the tab group of the positive electrode tab 14b is welded in a stacked state so as to be sandwiched between the positive electrode conductive member 24 and the stepped protective plate 26. Next, as shown in FIG. 9B, the front end side of the laminated tab group is bent in a state where the front end side of the protection plate 26 is bent so as to be substantially perpendicular to the laminated tab group of the positive electrode tab 14b. Thereafter, as shown in FIG. 9C, the protective plate 26 is bent so as to be parallel to the positive electrode conductive member 24, and the bent portion on the tip side of the laminated tab group is stepped with the positive electrode conductive member 24. In a state of being accommodated between the protective plate 26 and the protective plate 26. Finally, the positive electrode conductive member 24 and the protective plate 26 are parallel to the end surface of the electrode assembly 12 at the base end side from the portion where the positive electrode tab 14 b is sandwiched between the positive electrode conductive member 24 and the protective plate 26. It may be bent. The same applies to the negative electrode tab 15b.

  ○ The bent portion of the positive electrode tab 14b and the negative electrode tab 15b is not on the root side from the half of the inclined surface 17 formed by the tip of each positive electrode tab 14b or each negative electrode tab 15b, as shown in FIG. Moreover, the tip side may be more than half of the portion of the inclined surface 17. In this case, even if a flat plate is used instead of the stepped plate as the protective plate 26, the bent portion on the tip side of the laminated tab group is accommodated between the positive electrode conductive member 24 and the stepped protective plate 26. be able to. When a flat plate is used as the protective plate 26, the production of the protective plate 26 is simplified.

The folding position of the positive electrode tab 14b and the negative electrode tab 15b may be half the position of the inclined surface 17 formed by the positive electrode tab 14b or the tip of each negative electrode tab 15b.
The conductive member and protective plate welded to the positive electrode tab 14b or the negative electrode tab 15b may be made of a material different from that of the positive electrode tab 14b or the negative electrode tab 15b.

  The electrode assembly 12 is not limited to a stacked electrode assembly, and may be a wound electrode assembly in which a belt-like positive electrode and a negative electrode are wound in a stacked state with a separator interposed therebetween. For example, as shown in FIG. 10B, the wound electrode assembly 30 is wound with the strip-like positive electrode and negative electrode wound in a state where the separator 31 exists on the outer peripheral side, and the winding axis direction is two. The secondary battery 10 is housed in the case 11 in a state in which the case 11 is in the horizontal direction. The positive electrode tab 32 protrudes from one end side in the axial direction of the electrode assembly 30, and the negative electrode tab 33 protrudes from the other end side. The positive electrode tab 32 is electrically connected to the positive electrode terminal 35 via the positive electrode conductive member 34, and the negative electrode tab 33 is electrically connected to the negative electrode terminal 37 via the negative electrode conductive member 36.

In the stacked electrode assembly 12, the positive electrode tab 14 b and the negative electrode tab 15 b are not limited to the configuration protruding from the end surface on the same side of the electrode assembly 12, and may protrude from different end surfaces.
The welding of the positive electrode tab 14b or the negative electrode tab 15b and the conductive member and the protective plate is not limited to resistance welding, but may be other welding methods, for example, ultrasonic welding.

  The electrode, that is, the positive electrode 14 and the negative electrode 15 only need to have the active material layers 14a and 15a on at least one side of the metal foil 13, and may have a configuration having the active material layers 14a and 15a on one side instead of both sides. .

O Instead of forming the positive electrode tab 14b or the negative electrode tab 15b by projecting a part of the metal foil 13, the metal foil 13 may be formed by welding a metal foil serving as a tab.
○ In the stacked electrode assembly 12, the separator 16 exists between the positive electrode 14 and the negative electrode 15. For example, one of the positive electrode 14 and the negative electrode 15 is formed in a bag shape without using the sheet-like separator 16. The separators and the electrodes that are not accommodated in the bag-shaped separator may be alternately stacked.

The secondary battery 10 does not require an electrolytic solution, and for example, the separator 16 may be formed of a polymer electrolyte.
The secondary battery 10 is not limited to a lithium ion secondary battery, and may be another secondary battery such as a nickel hydride secondary battery, a nickel cadmium secondary battery, or a magnesium secondary battery.

  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.

  DESCRIPTION OF SYMBOLS 10 ... Secondary battery as a power storage device, 12, 30 ... Electrode assembly, 14 ... Positive electrode, 14b, 32 ... Positive electrode tab, 15 ... Negative electrode, 15b, 33 ... Negative electrode tab, 17 ... Inclined surface, 21, 35 ... Electrode Positive electrode terminal as terminal, 22, 37 ... Negative electrode terminal as electrode terminal, 24, 34 ... Conductive member for positive electrode as conductive member, 25, 36 ... Conductive member for negative electrode as conductive member, 26 ... Protection plate.

Claims (5)

An electrode assembly having a layered structure in which a positive electrode and a negative electrode are insulated, and each of the positive electrode and the negative electrode is electrically connected to an electrode terminal via a conductive member in a stacked state. A power storage device comprising:
The positive electrode tab and the negative electrode tab are each laminated so that the tip portion forms an inclined surface, and welded on the proximal side in a state sandwiched between the conductive member and the protective plate from the lamination direction, A power storage device, wherein the positive electrode tab and the tip side of the negative electrode tab are housed between the conductive member and the protective plate in a bent state.   2. The power storage device according to claim 1, wherein the bent portion of the positive electrode tab and the negative electrode tab is on the front end side with respect to half of the inclined surface portion.   The power storage device according to claim 2, wherein the protection plate is a flat plate.   The power storage device according to claim 1, wherein a bent portion of the positive electrode tab and the negative electrode tab is closer to a base side than a half of the inclined surface portion.   The power storage device according to claim 4, wherein the protection plate is a stepped plate.