JP2014026735A - Power storage device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power storage device capable of preventing scattering of broken pieces when a case is broken.SOLUTION: A secondary battery 10 includes a case 12, an electrode assembly body 20 housed in the case 12, and a positive-electrode terminal 41 and a negative-electrode terminal 42 each having one end electrically connected to the electrode assembly body 20 and the other end protruding outside the case 12. The secondary battery 10 has a resin sheet 50 covering, as a vacuum, the case 12 from an outside-surface side, and the resin sheet 50 has insertion holes 50a at positions where the positive-electrode terminal 41 and the negative-electrode terminal 42 are located. The positive-electrode terminal 41 and the negative-electrode terminal 42 protrude outside the resin sheet 50 through the insertion holes 50a.

Description

  The present invention relates to a power storage device including a case, an electrode assembly housed in the case, and an electrode terminal having one end electrically connected to the electrode assembly and the other end protruding outside the case.

  Conventionally, in a case of a secondary battery, a case main body and a lid are configured as separate parts, and after housing the electrode assembly, the lid is fixed by welding so as to cover the opening of the case main body. In addition, the case prevents the reaction of the electrode assembly (power generation element) in the case from excessively charging due to overcharging, etc., and the generation and accumulation of gas inside the case to prevent the internal pressure from rising abnormally. A safety valve is provided for venting the internal gas when the internal pressure exceeds a set pressure (see, for example, Patent Document 1).

  Patent Document 1 discloses that at least one of the four outer corners of a rectangular case (case body) made of synthetic resin is made thinner than the other outer corners to function as an explosion-proof safety valve. It is disclosed that the curvature radius of at least one inner corner of the four inner corners is made smaller than the curvature radius of the other inner corners to function as an explosion-proof safety valve. The thin portion is formed by providing a notch at the corner.

JP 10-144279 A

By the way, when the internal pressure of the square case is abnormally increased and the explosion-proof safety valve or the square case is broken, there is a possibility that broken pieces and the like are scattered along with the breakage.
An object of the present invention is to provide a power storage device that can prevent scattering of broken pieces when a case breaks.

  In order to solve the above-mentioned problems, the invention according to claim 1 includes a case, an electrode assembly accommodated in the case, one end electrically connected to the electrode assembly, and the other end of the electrode assembly. An electrode terminal that protrudes outside the case, and has a resin sheet that covers one or more cases in a vacuum state from the outer surface side, and the resin sheet has a position of the electrode terminal The gist of the present invention is that an insertion hole is formed in the first electrode and the electrode terminal protrudes outside the resin sheet through the insertion hole.

  According to this, when the reaction of the electrode assembly in the case proceeds excessively due to overcharge, etc., gas is generated and accumulated inside the case, and the internal pressure rises abnormally, the case is provided with a safety valve The safety valve is broken, and the case is broken when there is no safety valve. At this time, even if a broken piece occurs due to the breakage of the safety valve or the case, the broken piece is received by the resin sheet that covers the case from the outside in a vacuum state, and the broken piece is prevented from being scattered outside the resin sheet. The Note that “vacuum” includes not only a complete vacuum in which no substance is present but also a state filled with a gas having a pressure lower than atmospheric pressure.

  In addition, the insertion portion, which is at least a portion disposed in the insertion hole in the electrode terminal, is formed in a flat plate shape in which a cross section perpendicular to the protruding direction of the electrode terminal extends to one side, and the resin sheet is A connection surface that is in close contact with the insertion portion and that is electrically connected to an electrical connection member wider than a cross-sectional area of the insertion portion may be formed at the other end of the electrode terminal.

  According to this, for example, when the cross section of at least a portion (insertion portion) disposed in the insertion hole is formed in a circular shape, the inner surface of the insertion hole is hardly adhered to the outer surface of the insertion portion, and the resin sheet It becomes difficult to maintain the vacuum state inside. Like the present invention, by making the cross section of the insertion part into a flat plate extending long in one side, the degree of adhesion of the inner surface of the insertion hole with respect to the outer surface of the insertion part is increased compared to the case where the cross section is circular, and the inside of the resin sheet It becomes easy to maintain the vacuum state. Further, the area of the connection surface is wider than the cross-sectional area of the insertion portion. Therefore, while increasing the close contact degree of the inner surface of the insertion hole with respect to the insertion portion, it is possible to secure a contact area with the electrical connection member on the connection surface, and suppress an increase in electrical resistance due to the decrease in the contact area. be able to.

In addition, the length of the insertion portion in the direction extending in the long direction may be set longer than the length of the connection surface along the direction.
According to this, the cross-sectional area of the insertion portion further increases, and the passage of electricity at the electrode terminal increases, so that the electrical resistance at the electrode terminal can be reduced.

Further, the insertion portion may be formed in a connection portion that extends in a plate shape in the protruding direction, and the connection surface extends in a plate shape in a direction intersecting the protruding direction.
According to this, by making the cross section of the insertion portion into a flat plate extending long in one side, the degree of adhesion of the inner surface of the insertion hole with respect to the outer surface of the insertion portion is increased compared to the case where the cross section is circular, and the inside of the resin sheet It becomes easy to maintain a vacuum state. Moreover, the area of a connection surface is also ensured, a contact area with an electrical connection member can be secured on the connection surface, and an increase in electrical resistance due to a decrease in the contact area can be suppressed.

The electrode terminal may be formed by bending a plate material.
According to this, an electrode terminal can be manufactured easily.
Moreover, the said resin-made sheet | seat may cover the said one case in the vacuum state from the outer surface side.

  According to this, when a module is formed by arranging a plurality of power storage devices side by side, it is possible to prevent scattering of broken pieces when the case of the power storage device breaks, and other power storage devices can be damaged. Can prevent and protect the module.

  The power storage device is a secondary battery.

  According to the present invention, it is possible to prevent the fragments from being scattered when the case is broken.

(A) is a disassembled perspective view of a secondary battery, (b) is a bb line sectional view of Drawing 1 (a) showing a positive electrode terminal. The perspective view which shows the external appearance of a secondary battery. The disassembled perspective view which shows the component of an electrode assembly. Sectional drawing which shows the electrode assembly accommodated in the case. The partially broken perspective view which shows the inside of a battery pack. The perspective view which shows another example of an electrode terminal. The perspective view which shows another example of an electrode terminal.

Hereinafter, an embodiment embodying the present invention will be described with reference to FIGS.
In a secondary battery 10 as a power storage device, an electrode assembly 20 is accommodated in a metal case 12. The case 12 includes a rectangular parallelepiped case main body 13 and a rectangular flat plate-shaped lid member 14 that closes an opening of the case main body 13. Both the case body 13 and the lid member 14 are made of metal (for example, stainless steel or aluminum), and the case body 13 and the lid member 14 are joined by laser welding. Further, the secondary battery 10 of the present embodiment is a prismatic battery whose outer periphery forms a square shape. Further, the secondary battery 10 of the present embodiment is a lithium ion battery. The lid member 14 is formed with a safety valve 14 b for exhausting the gas generated in the case 12. In addition, as shown in FIG. 4, an insulating sheet is provided between the inner surface of the case 12 and the electrode assembly 20 in order to suppress a short circuit between the electrode assembly 20 and the case 12 (the case main body 13 and the lid member 14). 27 is provided.

  As shown in FIG. 3, the electrode assembly 20 includes a positive electrode 21 and a negative electrode 22, and a laminated body having a layer shape with a separator 23 interposed between the positive electrode 21 and the negative electrode 22. Has been. The positive electrode 21 includes a rectangular metal foil for positive electrode (in this embodiment, an aluminum foil) 21a, and a positive electrode active material layer 21b formed on both surfaces of the metal foil for positive electrode 21a. The positive electrode active material layer 21b is formed by applying an active material mixture containing active material particles for positive electrode to both surfaces of the positive electrode metal foil 21a and drying it. The negative electrode 22 includes a rectangular negative electrode metal foil (copper foil in the present embodiment) 22a and negative electrode active material layers 22b formed on both surfaces of the negative electrode metal foil 22a. The negative electrode active material layer 22b is formed by applying an active material mixture containing active material particles for negative electrode to the metal foil 22a for negative electrode and drying it.

  A positive electrode current collecting tab 31 formed by extending the positive electrode metal foil 21 a is provided at a part of the first end 21 c (one side direction (long side direction)) of the positive electrode 21. The positive electrode current collecting tab 31 is formed in the same position and in the same shape in each positive electrode 21 constituting the electrode assembly 20. A negative electrode current collecting tab 32 formed by extending the negative electrode metal foil 22a is provided at a part of the first end 22c (one side direction (long side direction)) of the negative electrode 22. The negative electrode current collecting tab 32 is formed in the same position and in the same shape in each negative electrode 22 constituting the electrode assembly 20.

  As shown in FIG. 1, the positive electrodes 21 constituting the electrode assembly 20 are stacked such that the respective positive electrode current collecting tabs 31 are arranged in a row along the stacking direction. Similarly, the negative electrode 22 constituting the electrode assembly 20 is laminated so that the respective negative electrode current collecting tabs 32 are arranged in a row along the lamination direction so as not to overlap the positive electrode current collecting tabs 31. . The plurality of positive electrode current collecting tabs 31 are collected in a range from one end to the other end of the electrode assembly 20 in the stacking direction. Similarly, the plurality of negative electrode current collecting tabs 32 are collected in a range from one end to the other end in the stacking direction of the electrode assembly 20.

  The electrode assembly 20 has a positive electrode tab group 45 formed by collecting positive electrode current collecting tabs 31. At least the outermost positive electrode current collecting tab 31 of the positive electrode tab group 45 is welded to a positive electrode conductive member 35 as a conductive member. The electrode assembly 20 has a negative electrode tab group 46 formed by collecting the negative electrode current collecting tabs 32. At least the outermost negative electrode current collecting tab 32 of the negative electrode tab group 46 is welded to a negative electrode conductive member 36 as a conductive member.

  As shown in FIG. 4, a positive electrode terminal 41 is connected to the positive electrode conductive member 35, and a negative electrode terminal 42 is connected to the negative electrode conductive member 36. In the positive electrode terminal 41 and the negative electrode terminal 42, the direction protruding from the electrode assembly 20 is the protruding direction of the positive electrode terminal 41 and the negative electrode terminal 42. The positive electrode terminal 41 and the negative electrode terminal 42 have flat plate-like insertion portions 41 a and 42 a on the positive electrode conductive member 35 and negative electrode conductive member 36 side. The insertion portions 41a and 42a are formed in an elongated square shape in a cross section orthogonal to the protruding direction. The insertion portions 41a and 42a are connected to the positive electrode conductive member 35 and the negative electrode conductive member 36 and are electrically connected. Further, in the positive electrode terminal 41 and the negative electrode terminal 42, connection portions 41b and 42b are connected to the distal end side from the insertion portions 41a and 42a in the protruding direction. The connecting portions 41b and 42b are formed in a columnar shape that gradually increases in diameter toward the tips of the positive terminal 41 and the negative terminal 42 along the protruding direction.

  As shown in FIGS. 1A and 1B, circular and flat connection surfaces 41c and 42c are formed at the tips of the connection portions 41b and 42b. Further, the positive terminal 41 and the negative terminal 42 are arranged in the direction in which the first ends 21c and 22c of the positive electrode 21 and the negative electrode 22 extend, respectively, in the long side direction (the direction extending long in one direction) in the cross-sectional shape of the insertion portions 41a and 42a. ) Is connected to the positive electrode conductive member 35 and the negative electrode conductive member 36. In the cross-sectional shape of the insertion portions 41a and 42a in the direction orthogonal to the protruding direction of the positive electrode terminal 41 and the negative electrode terminal 42, the length in the long side direction is shorter than the diameter of the connection surfaces 41c and 42c. Moreover, the area of the connection surfaces 41c and 42c is wider than the cross-sectional area of the insertion parts 41a and 42a in the direction orthogonal to the protruding direction. Furthermore, male screws 41d and 42d protruding from the center from the connection surfaces 41c and 42c are formed in the connection portions 41b and 42b.

  The positive terminal 41 and the negative terminal 42 protrude (expose) to the outside of the case 12 through a pair of opening holes 14 a arranged in parallel with the lid member 14 at a predetermined interval. Therefore, the protruding direction of the positive terminal 41 and the negative terminal 42 is the same as the protruding direction from the case 12.

  Each opening hole 14a is formed in a rectangular hole shape. Further, a rectangular annular insulating ring 19 a for insulation from the case 12 is attached to the insertion portions 41 a and 42 a of the positive terminal 41 and the negative terminal 42. When the insulating ring 19a is attached to the insertion portions 41a and 42a, the insertion portions 41a and 42a protrude outward from the upper end of the insulation ring 19a, and the insertion portions 41a and 42a protrude outside the case 12. .

  As shown in FIG. 4, in the positive terminal 41 and the negative terminal 42, the connection parts 41 b and 42 b are exposed outside the case 12 in addition to the insertion parts 41 a and 42 a. Thereby, the electric power of the electrode assembly 20 can be taken out of the case 12, and the electrode assembly 20 can be charged by supplying electric power to the electrode assembly 20.

  As shown in FIGS. 2 and 4, the case 12 having the above-described configuration is such that all the outer surfaces except for a part of the positive terminal 41 and the negative terminal 42 (connecting portions 41 b and 42 b) are covered with a resin sheet 50 in a vacuum state. It has been broken. For this reason, the inner surface of the resin sheet 50 is in close contact with the outer surface of the case 12, and the inside of the resin sheet 50 is kept in a vacuum state. Further, the resin sheet 50 has an insertion hole 50a at a position where the positive electrode terminal 41 and the negative electrode terminal 42 pass. Two insertion holes 50a are formed in the extending direction of the first ends 21c and 22c of the positive electrode 21 and the negative electrode 22 in the electrode assembly 20. Moreover, the insertion hole 50a is formed in the shape of an elongated square hole substantially the same as the cross-sectional shape thereof so that the flat plate-like insertion portions 41a and 42a can pass therethrough. And as for the positive electrode terminal 41 and the negative electrode terminal 42, insertion part 41a, 42a protrudes in the resin-made sheets 50 through the insertion hole 50a. In other words, the positive electrode terminal 41 and the negative electrode terminal 42 protrude outside the case 12 through the insertion hole 50a. In the positive electrode terminal 41 and the negative electrode terminal 42, the inner surface of the insertion hole 50 a is in close contact with the outer surface of the insertion portions 41 a and 42 a, and the airtightness in the resin sheet 50 is maintained.

  As shown in FIG. 1, the resin sheet 50 is formed in a square bag shape having substantially the same size as the outer shape of the case 12, and an opening 50 b for accommodating the case 12 is opened on one side. Is used.

  In order to vacuum pack the case 12 with the resin sheet 50, first, the case 12 is accommodated in the resin sheet 50 from the opening 50b, and the positive terminal 41 and the negative terminal 42 are formed from the opening edge of the resin sheet 50. In the protruding state, the opening edges facing each other of the resin sheet 50 are welded leaving a part. At this time, the insertion hole 50a is formed by the opening edge of the resin sheet 50 surrounding the insertion portions 41a and 42a. The reason why a part of the opening edge is left is to secure a position for inserting a nozzle (not shown) of the vacuum drawing device into the resin sheet 50 when the resin sheet 50 is evacuated. .

  Then, a nozzle is inserted into the resin sheet 50 from an unwelded portion at the opening edge of the resin sheet 50, and the inside of the resin sheet 50 is evacuated by a vacuuming device. At this time, the inside of the resin sheet 50 is depressurized to a pressure lower than the atmospheric pressure. And while the inner surface of the resin sheet 50 is in close contact with the entire outer surface of the case 12, the inner surface of the insertion hole 50a is in close contact with the outer surfaces of the insertion portions 41a and 42a, and the resin sheet 50 is in a vacuum state. Then, the nozzle is pulled out from the resin sheet 50. Next, the portion where the nozzle has been inserted is welded, and the opening 50b of the resin sheet 50 is sealed. As a result, the case 12 is vacuum-packed on the resin sheet 50 to form the secondary battery 10.

  As shown in FIG. 5, a plurality of the secondary batteries 10 having the above configuration are accommodated in a battery case 61 to form a battery pack 60 as a module. The battery case 61 is formed by assembling a pack case main body 62 that is formed in a square box shape and has an opening 62a on the upper surface, and a pack lid 63 that opens and closes the opening 62a. In the pack case main body 62, the long side direction is defined as a first direction, and the short side direction of the pack case main body 62, which is a direction orthogonal to the first direction, is defined as a second direction.

  In the pack case main body 62, a plurality of secondary batteries 10 are juxtaposed in the first direction of the pack case main body 62. In the secondary batteries 10 arranged in parallel, the positive electrode terminal 41 and the negative electrode terminal 42 are disposed on both ends of the pack case main body 62 in the second direction, but the secondary battery 10 is connected to the positive electrode terminal 41 in the first direction. The negative electrode terminals 42 are arranged alternately. That is, the secondary batteries 10 arranged in parallel in the first direction are arranged so that the positive terminal 41 of one secondary battery 10 and the negative terminal 42 of the adjacent secondary battery 10 are adjacent in the first direction. Is done.

  The positive electrode terminal 41 and the negative electrode terminal 42 in the secondary batteries 10 adjacent in the first direction are electrically connected by a bus bar 65 as an electric connection member. The conductive bus bar 65 is formed in a rectangular plate shape by a copper plate or the like. Circular through holes (not shown) are formed at positions spaced apart in the length direction of the bus bar 65. A terminal (a male screw 41 d of the positive terminal 41 or a male screw 42 d of the negative terminal 42) of one of the adjacent secondary batteries 10 is inserted into one through hole of the bus bar 65. In addition, the terminal (the male screw 42 d of the negative terminal 42 or the male screw 41 d of the positive terminal 41) of the other secondary battery 10 among the adjacent secondary batteries 10 is inserted into the other through hole of the bus bar 65. The male screws 41 d and 42 d are screwed into the nut 66 from the upper surface side of the bus bar 65 so as to penetrate the bus bar 65, and the bus bar 65 is fastened. In this fastened state, the bus bar 65 is in surface contact with the connection surface 41 c of the positive terminal 41 and the connection surface 42 c of the negative terminal 42.

Next, the operation of the secondary battery 10 will be described.
In the secondary battery 10, the entire outer surface of the case 12 is covered with a resin sheet 50 in a vacuum state. That is, the resin sheet 50 is in close contact with the outer surface of the case 12. For this reason, even if gas is generated and accumulated in the case 12 and the internal pressure abnormally rises and the safety valve 14b is broken and a broken piece is generated, the broken piece is received by the resin sheet 50 and is made of resin. It does not fly off the sheet 50.

According to the above embodiment, the following effects can be obtained.
(1) In the secondary battery 10, the entire outer surface of the case 12 is covered with a resin sheet 50 in a vacuum state. For this reason, even if broken pieces are generated due to an abnormality in the case 12, the broken pieces can be received by the resin sheet 50 and prevented from being scattered.

  (2) The resin sheet 50 bulges when the resin sheet 50 receives the gas or electrolyte solution leaked outside the case 12. For this reason, by confirming that the resin sheet 50 has expanded, it is possible to detect gas generation accompanying electrolyte overcharge of the secondary battery 10 and leakage of the electrolyte. In particular, even if gas is leaking, the resin sheet 50 swells, and thus gas leakage can be visually recognized, which is very effective.

  (3) The resin sheet 50 can receive the broken pieces and the electrolytic solution leaked outside the case 12. Therefore, it is possible to prevent broken pieces and electrolyte from flowing into the battery case 61 of the battery pack 60. Therefore, it is not necessary to perform protective treatment or insulation treatment on the secondary battery 10 or other peripheral members in case the broken pieces are scattered or the electrolyte leaks.

  (4) In the positive electrode terminal 41 and the negative electrode terminal 42, the insertion portions 41 a and 42 a that pass through the insertion holes 50 a of the resin sheet 50 are formed in a flat plate shape that has a cross-sectional shape and extends to one side. That is, the outer surfaces of the insertion portions 41a and 42a are formed in flat surfaces instead of arcuate surfaces. For this reason, when the resin sheet 50 is in a vacuum state, the inner surface of the insertion hole 50a tends to be in close contact with the outer surfaces of the insertion portions 41a and 42a, and the resin sheet 50 is easily maintained in a vacuum state.

  (5) In the positive electrode terminal 41 and the negative electrode terminal 42, the insertion portions 41a and 42a are formed in a flat plate shape having a cross-sectional shape and extending to one side, but circular connection surfaces 41c and 42c are formed in the connection portions 41b and 42b. did. Therefore, the area of the connection surfaces 41c and 42c joined to the bus bar 65 is larger than the cross-sectional area of the insertion portions 41a and 42a. Therefore, the contact area with the bus bar 65 can be secured at the connection portion with the bus bar 65 while the portion passing through the insertion hole 50a is flat, and the electrical resistance is increased by reducing the contact area. Can be suppressed.

  (6) In the secondary battery 10, the entire outer surface of the case 12 is covered with a resin sheet 50 in a vacuum state, and the entire case 12 is shielded from the atmosphere. For this reason, even if the reaction of the electrode assembly 20 proceeds excessively and gas is generated inside the case 12, the gas is prevented from coming into contact with oxygen in the atmosphere, and there is no risk of ignition.

  (7) The resin sheet 50 is formed in a square box shape that is substantially the same as the case 12. For this reason, when the case 12 is accommodated in the resin sheet 50, only a slight gap is formed between the outer surface of the case 12 and the inner surface of the resin sheet 50. Therefore, when the resin sheet 50 is evacuated, the resin sheet 50 can be quickly brought into close contact with the outer surface of the case 12, and the productivity of the secondary battery 10 can be increased.

In addition, you may change the said embodiment as follows.
The shape of the positive terminal 41 and the negative terminal 42 may be changed. As shown in FIG. 6, the lengths of the insertion portions 41 a and 42 a of the positive terminal 41 and the negative terminal 42 in the long side direction (direction extending long in one direction) in the cross-sectional shape are set to the insertion portions 41 a and 42 a of the embodiment. Make it longer. In this case, the length in the long side direction of the insertion parts 41a and 42a is made longer than the diameter of the connection surfaces 41c and 42c. If comprised in this way, the cross-sectional area of insertion part 41a, 42a will spread, and the electrical resistance in insertion part 41a, 42a can be reduced.

  As shown in FIG. 7, the positive terminal 71 and the negative terminal 72 may be formed by bending a conductor made of a rectangular plate material. One end of each of the positive electrode terminal 71 and the negative electrode terminal 72 is connected to the positive electrode conductive member 35 and the negative electrode conductive member 36 and is electrically connected thereto. The positive electrode terminal 71 and the negative electrode terminal 72 extend in a direction orthogonal to the insertion portions 71a and 72a projecting in a plate shape from the electrode assembly 20 (the positive electrode conductive member 35 and the negative electrode conductive member 36). The connection portions 71b and 72b are formed. Quadrangular connection surfaces 71c and 72c are formed on the upper surfaces of the connection portions 71b and 72b. The cross sections of the insertion portions 71a and 72a are formed in a flat plate shape extending in one direction, and the area of the connection surfaces 71c and 72c is wider than the cross-sectional area of the insertion portions 71a and 72a. In addition, although the positive electrode terminal 71 and the negative electrode terminal 72 were formed by bending a conductor, the connection portions 71b and 72b may be welded to the insertion portions 71a and 72a.

  In the embodiment, the cross-sectional shape of the insertion portions 41a and 42a is formed in a flat plate shape extending long in one side, and the connection portions 41b and 42b are formed in a columnar shape, but the shapes of the positive electrode terminal 41 and the negative electrode terminal 42 are appropriately It may be changed.

  In the embodiment, male screws 41d and 42d are projected from the connecting portions 41b and 42b, and nuts 66 are screwed into the male screws 41d and 42d penetrating the bus bar 65 to electrically connect the positive terminal 41 and the negative terminal 42 and the bus bar 65. However, the connection form may be changed as appropriate. For example, the bus bar 65 may be welded to the connection surfaces 41c and 42c, or a female screw may be recessed in the connection surfaces 41c and 42c, and a bolt penetrating the bus bar 65 may be screwed into the female screw for connection.

  In the embodiment, the positive electrode current collecting tab 31 and the negative electrode current collecting tab 32 are folded in a state of being collected (bundled) within a range from one end to the other end in the stacking direction of the electrode assembly 20. However, the positive electrode current collecting tab 31 and the negative electrode current collecting tab 32 may not be collected.

In the embodiment, one secondary battery 10 is covered with the resin sheet 50 in a vacuum state, but two or more secondary batteries 10 may be collectively covered with the resin sheet.
In the embodiment, the positive electrode 21 has the positive electrode active material layer 21 b on both sides, but may have the positive electrode active material layer 21 b only on one side of the positive electrode 21.

In the embodiment, the negative electrode 22 has the negative electrode active material layer 22b on both sides, but the negative electrode 22 may have the negative electrode active material layer 22b only on one side.
The number of the positive electrode 21 and the negative electrode 22 which comprise the electrode assembly 20 may be changed suitably.

The shape of the case 12 may be formed in a columnar shape or an elliptical column shape that is flat in the left-right direction.
The present invention may be embodied as a nickel hydride secondary battery as an electricity storage device or an electric double layer capacitor.

  DESCRIPTION OF SYMBOLS 10 ... Secondary battery as an electrical storage device, 12 ... Case, 20 ... Electrode assembly, 41 ... Positive electrode terminal as an electrode terminal, 42 ... Negative electrode terminal as an electrode terminal, 41a, 42a, 71a, 72a ... Insertion part, 71b , 72b ... connection portion, 41c, 42c, 71c, 72c ... connection surface, 50 ... resin sheet, 50a ... insertion hole, 65 ... bus bar as an electrical connection member.

Claims (7)

Case and
An electrode assembly housed in the case;
An electrode terminal having one end electrically connected to the electrode assembly and the other end protruding out of the case;
A power storage device comprising:
Having a resin sheet covering one or more cases in a vacuum state from the outer surface side;
An electrical storage device, wherein an insertion hole is formed in the resin sheet at the position of the electrode terminal, and the electrode terminal protrudes outside the resin sheet through the insertion hole.   The insertion portion, which is at least a portion disposed in the insertion hole in the electrode terminal, is formed in a flat plate shape in which a cross section perpendicular to the protruding direction of the electrode terminal extends to one side, and the resin sheet is inserted into the insertion hole. 2. The power storage device according to claim 1, wherein a connection surface is formed on the other end of the electrode terminal and is electrically connected to an electrical connection member that is larger than a cross-sectional area of the insertion portion. .   The power storage device according to claim 2, wherein a length of the insertion portion in a direction extending in the long direction is set to be longer than a length of the connection surface along the direction.   The said insertion part is formed in the connection part extended in plate shape in the direction which cross | intersects the said protrusion direction while the said connection surface is extended in plate shape in the said protrusion direction. Power storage device.   The power storage device according to claim 4, wherein the electrode terminal is formed by bending a plate material.   The power storage device according to any one of claims 1 to 5, wherein the resin sheet covers one case in a vacuum state from an outer surface side.   The power storage device according to any one of claims 1 to 6, wherein the power storage device is a secondary battery.