JP2020024877A - Power storage element - Google Patents

Abstract

To provide a laminate type power storage element having capacity capable of being increased without reducing performance by suppressing a positional deviation of an electrode body inside an exterior body without adding a new manufacturing process.SOLUTION: A power storage element 1 includes an electrode body 2 that is composed of a vertically laminated tabular positive electrode 4 and a tabular negative electrode 8, the electrode body stored in a flat bag-shaped exterior body 12 composed of laminate films (13a, 13b). The electrode body includes a collector 7 arranged on at least one of a top layer and an undermost layer. A laminate film facing the collector in the exterior body is made by laminating a heat seal layer 31 on one principal surface of metal foil 32 via an adhesion layer 34. The exterior body is made by performing heat welding on peripheral regions 14 of the laminate films laminated in a state in which heat seal layers are caused to vertically face each other. The electrode body is disposed in a region surrounded by the peripheral regions and heat welding on the heat seal layer is performed on the collector.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a laminated power storage element.

  In recent years, IC cards equipped with a one-time password function and a display, or extremely thin electronic devices (hereinafter, also referred to as devices) with a built-in power supply, such as tags and tokens (one-time password generators), have become widespread. In order to realize these devices, it is indispensable to reduce the size and thickness of power storage elements (primary batteries, secondary batteries, electric double-layer capacitors, etc.) serving as power sources. As a typical power storage element suitable for miniaturization and thinning, there is a laminate type power storage element described in Patent Document 1 below.

  FIG. 1A shows an appearance of a general laminated power storage element (hereinafter, also referred to as power storage element 101). FIG. 1B is an exploded perspective view of power storage element 101 shown in FIG. 1A. As shown in FIG. 1A, the power storage element 101 has a flat external shape, and an electrode body is sealed in a flat rectangular bag-shaped exterior body 12 made of a laminated film. Further, a positive electrode terminal plate 24 and a negative electrode terminal plate 28 (hereinafter, also collectively referred to as electrode terminal plates) are led out from one side of the rectangular exterior body 12.

  Next, a configuration of the power storage element 101 will be described with reference to FIG. 1B. In FIG. 1B, some members and parts are hatched so that they can be easily distinguished from other members and parts. As shown in FIG. 1B, the exterior body 12 is formed by heat-welding the peripheral regions 14 of two laminated films (113 a and 113 b) facing each other, and the electrode body 2 is provided inside the exterior body 12. It is enclosed together with an electrolytic solution (not shown).

  Here, assuming that the direction in which the two laminated films (113a, 113b) face each other is the up-down direction, the electrode body 2 is composed of a sheet-shaped positive electrode 4 and a sheet-shaped negative electrode 8 with a separator 6 interposed therebetween. And crimped in a state of being laminated. The positive electrode 4 has a positive electrode material 5 including a positive electrode active material disposed on one main surface of a positive electrode current collector 3 made of a metal plate or a metal foil. The negative electrode 8 is formed by disposing a negative electrode material 9 containing a negative electrode active material on one main surface of a negative electrode current collector 7 made of a metal plate, a metal foil, or the like. The positive electrode 4 and the negative electrode 8 are stacked such that the positive electrode material 5 and the negative electrode material 9 face each other with the separator 6 interposed therebetween. One end of a strip-shaped positive electrode terminal plate 24 and one end of a strip-shaped negative electrode terminal plate 28 are attached to the positive electrode current collector 3 and the negative electrode current collector 7, respectively. The other end sides of the positive electrode terminal plate 24 and the negative electrode terminal plate 28 are led out from one side of the exterior body 12.

  If the power storage element 101 is a lithium primary battery, the positive electrode 4 is a slurry in which a positive electrode material 5 containing a positive electrode active material such as manganese dioxide is coated on the surface of the positive electrode current collector 3, The negative electrode 8 has no negative electrode current collector 7 and is made of a foil-shaped or flat-shaped lithium metal or lithium alloy (hereinafter also referred to as negative electrode lithium). Then, a negative electrode terminal plate 28 is attached to the lower surface of the negative electrode lithium.

  Next, the structure of the laminate films (113a, 113b) used for the exterior body 12 of the power storage element 101 will be described. FIG. 2 shows a cross-sectional structure of the laminate films (113a, 113b). FIG. 2 is a vertical cross-sectional view corresponding to a cross section taken along the line aa of FIG. 1A. The laminate films (113a, 113b) are heat-laminated and are manufactured by a well-known extrusion lamination method. As shown in FIG. 2, the laminated films (113a, 113b) are made of a metal foil 32 such as an aluminum foil or a stainless steel foil as a base material, and one main surface of the metal foil 32 has a heat-fusing property such as polypropylene. A heat seal layer 31 made of resin is laminated, and a protective layer 33 made of PET or the like is laminated on the other surface. The exterior body 12 is formed in a bag-like shape by laminating the two laminated films (113a and 113b) such that the heat seal layers 31 face each other, and the peripheral regions 14 are thermally welded to each other. It was processed into.

  The following Non-Patent Document 1 describes the characteristics, discharge performance, and the like of a thin lithium manganese dioxide primary battery, which is a laminated power storage element that is actually sold as a product.

Japanese Patent No. 5668785

FDK Corporation, "Thin Lithium Primary Battery", [online], [Searched June 25, 2018], Internet <URL: http://www.fdk.co.jp/battery/lithium/lithium_thin.html>

  1A, 1B, and 2, the planar size and thickness of the power storage element 101 are predetermined, so that a high-capacity power storage element 101 is realized. It is necessary to increase the plane size of the electrode body 2 so as to be as close as possible to the area of the area inside the peripheral area 14 of the exterior body 12. However, when the planar size of the electrode body 2 is increased, the distance between the peripheral region 14 of the exterior body 12 and the periphery of the electrode body 2 becomes extremely small. Therefore, even if the position of the electrode body 2 is slightly displaced within the exterior body 12, the corners (FIG. 2, reference numeral 10) of the electrode body 2 may hit the inner surface of the exterior body 12, and the heat seal layer 31 may be cracked. is there.

  When a crack is generated in the heat seal layer 31 of the exterior body 12, the metal foil 32, which is the base material of the laminated film (113a, 113b) insulated by the heat seal layer 31, and the current collector (3, 7) conduct. I do. In order to prevent conduction due to the cracks in the heat seal layer 31, the electrode body 2 is covered with an insulating tape, and between the laminate films (113a, 113b) and the current collectors (3, 7) of the electrode body 2. A method of interposing an insulating tape is also conceivable. However, if the electrode body 2 is covered with the insulating tape, the power storage element 101 becomes thicker, which goes against the demand for a thinner power storage element 101. To keep the thickness of the storage element 101 equal to that without the insulating tape, it is necessary to reduce the thickness of the electrode body 2, and it is difficult to increase the capacity of the storage element 101. In addition, a step of covering the insulating tape with the electrode body 2 is also required, which causes an increase in the manufacturing cost of the power storage element 101.

  Accordingly, an object of the present invention is to provide a laminate-type power storage element that can suppress displacement of an electrode body inside an exterior body without increasing the number of manufacturing steps and can increase the capacity without deteriorating performance. And

In one embodiment of the present invention for achieving the above object, an electrode body in which a flat positive electrode and a flat negative electrode are vertically stacked is housed in a flat bag-shaped exterior body made of a laminate film. A storage element,
The electrode body, a current collector is disposed on at least one of the uppermost layer and the lowermost layer,
In the exterior body, a laminate film facing the current collector is formed by laminating a heat seal layer on one main surface of a metal foil via an adhesive layer,
The outer package is formed by heat-welding a peripheral region of a laminated film laminated in a state where the heat seal layer faces each other in a vertical direction,
The electrode body is heat-welded to the heat seal layer while being disposed in a region surrounded by the peripheral region,
An electric storage element characterized by the above-mentioned.

  The laminate film may include the heat seal layer made of a modified polyolefin resin.

  The current collector thermally welded to the heat seal layer may be a power storage element made of austenitic stainless steel.

  A power storage element having only one sheet-like positive electrode and one negative electrode may be used.

  A power storage element including a negative electrode made of lithium metal or a lithium alloy, wherein an indeterminate-shaped electrolyte is housed inside the exterior body, and a positive electrode current collector is thermally welded to the heat seal layer may be used. .

Further, in the method for manufacturing a power storage element described above,
A step of disposing the electrode body between laminated films facing each other in the vertical direction, and thermally bonding the heat seal layer and the current collector by thermocompression bonding an arrangement area of the electrode body,
A sealing step of sealing the outer package by thermocompression bonding of a peripheral region of the laminate film facing in the vertical direction,
The method for manufacturing a power storage element, which includes the above, is also within the scope of the present invention.

  According to the present invention, it is possible to suppress the displacement of the electrode body inside the exterior body without increasing the number of manufacturing steps, and to increase the capacity of the laminate type power storage element without deteriorating the performance, and the laminate type power storage element. A method for manufacturing a storage element is provided.

FIG. 2 is a diagram illustrating an appearance of a general laminate type power storage element 101. FIG. 2 is an exploded perspective view of a general laminate type electric storage element 101. FIG. 2 is an enlarged cross-sectional view of a sealing portion of a general laminate type power storage element 101. It is an expanded sectional view of the sealing part of the lamination type electric storage element concerning the example of the present invention. It is a longitudinal section of the lamination film which constitutes the upper part of the exterior body with which the electric storage element concerning the example of the present invention is provided. FIG. 9 is a diagram illustrating a principle of generation of conduction between a metal foil of an exterior body and an electrode body in a conventional power storage element. FIG. 4 is a diagram illustrating a principle of suppressing conduction between a metal foil of an exterior body and an electrode body in a power storage element according to an embodiment of the present invention.

  Embodiments of the present invention will be described below with reference to the accompanying drawings. In the drawings used in the following description, the same or similar parts are denoted by the same reference numerals, and redundant description may be omitted. In addition, depending on the drawings, unnecessary reference numerals may be omitted in the description.

=== Problems of conventional sealing structure ===
1A, 1B, and 2, in the conventional power storage element 101, as described above, when the plane size of the electrode body 2 is increased, even if the position of the electrode body 2 in the exterior body 12 is slightly shifted, There is a possibility that cracks may occur in the heat seal layer 31 of the laminate films (113a, 113b). Therefore, in order to achieve an increase in the capacity of the electric storage element 101 while maintaining the outer diameter dimension, it is necessary to align the electrode body 2 with extremely high precision and arrange it in the exterior body 12. For example, power storage element 101 incorporated in an IC card has a plane size of 27 mm × 22 mm and a thickness of 0.45 mm. In addition, this power storage element 101 requires a positioning accuracy of about 200 μm.

  The inventor fixed the position of the electrode body 2 inside the exterior body 12 by heat-welding the heat seal layer 31 to the upper end surface of the positive electrode current collector 3 arranged on the uppermost layer of the electrode body 2. It was thought that if it was possible, the displacement of the electrode body 2 could be suppressed, and the occurrence of mechanical damage such as cracks to the heat seal layer 31 could be prevented. Based on such considerations, the inventor has conducted intensive studies on the optimum structure of the laminate films (113a, 113b) constituting the exterior body 12, the method of fixing the electrode body 2 inside the exterior body 12, and the like. Again, the present invention has been reached.

=== Example ===
<Configuration of storage element>
As a power storage element according to an embodiment of the present invention, a laminated lithium primary battery using negative electrode lithium as a negative electrode will be described. FIG. 3 shows a power storage device 1 according to an embodiment of the present invention. FIG. 3 is a vertical cross-sectional view of the electric storage element 1, in which a sealing portion is shown in an enlarged manner. As shown in FIG. 3, the basic structure and configuration of the power storage device 1 according to the embodiment of the present invention are the same as those of the general laminate type power storage device 101 shown in FIG. However, in the electric storage element 1 according to the embodiment, the exterior body 12 is formed of a laminate film (13a, 13b) having a structure different from that of the laminate film (113a, 113b) shown in FIG.

  FIG. 4 is a longitudinal sectional view of the upper laminate film 13a in contact with the positive electrode current collector 3 in the outer package 12 of the power storage device 1 according to the embodiment of the present invention. Here, in the laminated film 13a, when the inside and outside directions are defined as the protective layer 33 is arranged on the outside, the laminated film 13a is used for the conventional electricity storage element 101 as shown in FIG. Similarly to the laminated film 13a, a protective layer 33 is laminated on the outer side of the metal foil 32 as the base material. However, a laminate film 13a manufactured by a well-known dry lamination method is used as a laminate film (hereinafter, also referred to as a laminate film 13a of the embodiment) used for the exterior body 12 of the power storage device 1 of the present embodiment. An adhesive layer 34 is provided between the metal foil 32 and the innermost heat seal layer 31. Then, in the electric storage element 1 according to the embodiment, the heat seal layer 31 of the laminate film 13a is thermally welded to the positive electrode current collector 3. In the storage element 1 according to the present embodiment, the two laminated films (13a, 13b) constituting the exterior body 12 are both manufactured by a dry lamination method (hereinafter, a dry-laminated film is referred to as a dry-laminated film for convenience). However, at least the upper laminate film 13a that contacts the positive electrode current collector 3 may be a dry laminate type. That is, the lower laminate film 13a may be a conventional heat-laminated film (hereinafter also referred to as a heat-laminated film for convenience).

  By the way, in the electric storage element 1 according to the embodiment, the positive electrode current collector 3 is made of austenitic stainless steel (18Cr-8N). As is well known, austenitic stainless steel is a conductor having a high Young's modulus. In other words, the positive electrode current collector 3 made of austenitic stainless steel has high rigidity even if it is thin, and contributes to making the power storage element 1 thin.

  However, it is generally difficult to heat weld a thermoplastic resin to the surface of stainless steel. Therefore, in the electric storage element 1 of the present embodiment, the heat seal layer 31 of the laminate film (13a, 13b) is made of a modified polyolefin resin. The modified polyolefin-based resin can heat-seal the laminated film 13 a to the positive electrode current collector 3 made of stainless steel, and can fix the electrode body 2 at a predetermined position inside the exterior body 12. Therefore, in the electric storage element 1 according to the embodiment, the displacement of the electrode body 2 is prevented, and mechanical damage such as a crack due to the contact with the heat seal layer 31 is unlikely to occur. In the power storage element 1, since the inner surface of the outer package 12 is directly thermally welded to the upper end surface of the positive electrode current collector 3, a fixing member such as an insulating tape for fixing the outer package 12 and the electrode assembly 2. Becomes unnecessary. That is, in the electric storage element 1 of this embodiment, the internal space of the exterior body 12 is effectively used, the plane size of the electrode body 2 can be made as large as possible, and the fixing member and the electrode member 2 can be reduced in cost associated with the process of insulating it.

  In addition, a procedure for sealing the electrode body 2 inside the exterior body 12 by heat-welding the peripheral regions 14 of the two laminated films (13a, 13b), and applying the laminated film 13a to the positive electrode current collector 3 of the electrode body 2 As a procedure for welding, first, after the electrode body 2 is disposed between the upper rectangular laminated film 13a and the lower rectangular laminated film 13b shown in FIG. 4, two rectangular laminated films (13a, 13b) are formed. Are sealed on three sides of the peripheral region 14. Thereby, the bag-shaped exterior body 12 having one side opened is manufactured. Then, the housing area of the electrode body 2 is thermocompression-bonded from the outside of the upper laminate film 13 a to thermally bond the laminate film 13 a to the upper surface of the positive electrode current collector 3. Then, after injecting the electrolytic solution into the bag-shaped exterior body 12, one side opening in the peripheral region 14 of the exterior body 12 is sealed to complete the power storage device 1.

  Note that the conditions of thermocompression bonding to the peripheral region 14 of the exterior body 12 are different from the conditions at the time of thermocompression bonding of the electrode body 2. In this embodiment, when the peripheral region 14 is thermally welded, the temperature, The pressure and the time are set to 180 ° C., 0.1 MPa and 3 sec, respectively, and when the laminate film 13 a and the electrode body 2 are thermally welded, the temperature, the pressure and the time are set to 160 ° C. and 0.1 MPa, respectively. , 1 sec.

  By the way, in the conventional electric storage element 101 using the heat laminated type film, in the step of thermocompression bonding the electrode body 2 and the laminated film 113a, conduction between the metal foil 32 of the laminated film 113a and the positive electrode current collector 3 is performed. There was a problem that occurred. FIG. 5A shows a principle of occurrence of conduction between the metal foil 32 of the laminate film 113a and the electrode body 2 in the conventional electric storage element 101. As shown in FIG. 5A, in the conventional power storage element 101, when the electrode body 2 is thermally welded to the inner surface of the laminate film 113a, one of the positive electrode material 5 and the positive electrode current collector 3 is generated by heat or load applied to the electrode body 2. When the portion is damaged, fine fragments 41 generated by the damage damage the inner surface of the exterior body 12, and in some cases, the fragments 41 penetrate the heat seal layer 31 of the laminate film 113 a and come into contact with the metal foil 32. In such a case, since the fragments 41 of the electrode body 2 have conductivity, conduction occurs between the metal foil 32 of the exterior body 12 and the electrode body 2. Further, when the electrode body 2 is heat-welded to the inner surface of the laminate film 113a, even if the heating temperature or the strength of the pressing force is controlled to be constant, the heating temperature is high or the heating temperature is high. If the pressing force is strong, the upper part of the positive electrode current collector 3 may sink into the heat seal layer 31 and come into contact with the metal foil 32 to cause conduction between the two.

  On the other hand, in the electricity storage device 1 according to the present embodiment, a dry laminate type film is used for the laminate film 13a, so that the occurrence of conduction between the metal foil 32 of the exterior body 12 and the electrode body 2 can be suppressed. It has become. FIG. 5B illustrates a principle of suppressing conduction between the metal foil 32 of the laminate film 13a and the electrode body 2 in the power storage device 1 according to the example. In the electric storage element 1 according to the embodiment, the laminate film 13a in which the adhesive layer 34 is interposed between the heat seal layer 31 and the metal foil 32 is used for the exterior body 12, and the housing area of the electrode body 2 is thermocompression-bonded. Even if the fragments 41 of the electrode body 2 generated in the process penetrate the heat seal layer 31, the adhesive layer 34 inhibits the contact between the fragments 41 and the metal foil 32. Further, even if the upper portion of the positive electrode current collector 3 sinks into the heat seal layer 31, the adhesive layer 34 hinders the contact between the positive electrode current collector 3 and the metal foil 32. That is, in the electric storage element 1 according to the embodiment, the adhesive layer 34 of the laminate film 13a functions as a barrier layer.

=== Performance evaluation ===
Next, the storage element 1 according to the example of the present invention was manufactured as a sample, and the effect of suppressing conduction between the metal foil 32 of the exterior body 12 and the electrode body 2 in the sample was evaluated. In the manufactured sample (hereinafter, also referred to as a sample of the example), the thickness of the adhesive layer 34 in the laminate film 13a is about 1 μm to 3 μm. 1 has the same structure, configuration, and size as the thin lithium manganese dioxide primary battery described as CF042722U.

  Further, as a sample of the comparative example, a lithium primary battery provided with an outer package 12 made of a heat-laminated film (113a, 113b) was produced in the same manner as the conventional general power storage element 1. The sample of this comparative example and the sample of the example are different only in the structure of the laminate films (13, 113). All the samples are laminated on the upper surface of the positive electrode current collector 3 in the storage area of the electrode body 2. The heat seal layer 31 of the film (13a, 113a) is thermally welded. Then, 1000 samples were prepared for each of the samples of the example and the comparative example, and the insulation test was performed for all the samples. Specifically, a probe is applied to the laminate film (13a, 113a) on the positive electrode 4 side of each sample, and a DC voltage of 5.0 V is applied between the laminate film (13a, 113a) and the positive electrode terminal plate 24. The resistance between the metal foil 32 of the laminated films (13a, 113a) and the positive electrode terminal plate 24 was measured using an insulation resistance meter.

  Table 1 below shows the results of the insulation test for each sample.

表１に示したように、比較例のサンプルでは、製品に対する絶縁検査において不良とされる１００ＭΩ未満の抵抗値を示した個体が１２個あった。すなわち、不良率が１．２％であった。一方、実施例のサンプルでは、全ての個体が１００ＭΩ以上の抵抗値を有して全数が良品として判定された。さらに、比較例のサンプルでは、良品として判定されたものの、１００ＭΩ以上５００ＭΩ未満の抵抗値を示した個体が９個あり、５００ＭΩ以上１０００ＭΩ未満の抵抗値を示した個体が１２個あった。一方、実施例のサンプルでは、１００ＭΩ以上５００ＭΩ未満の抵抗値を示した個体がなく、５００ＭΩ以上１０００ＭΩ未満の抵抗値を示した個体は３個だけであった。すなわち、１０００個中、９９７個の個体が１０００ＭΩ以上の抵抗値を示し、極めて優れた絶縁性能を有していた。したがって、ドライラミネート型フィルムを外装体１２に用いた実施例のサンプルでは、図５Ｂに示した原理によって外装体１２内に正極４の破片４１が存在しても接着層３４がバリア層として機能していることが確認できた。

As shown in Table 1, in the sample of the comparative example, there were 12 individuals having a resistance value of less than 100 MΩ which was regarded as defective in the insulation test for the product. That is, the defect rate was 1.2%. On the other hand, in the samples of the examples, all the individuals had a resistance value of 100 MΩ or more, and all the samples were determined to be good. Furthermore, in the sample of the comparative example, there were 9 individuals that exhibited a resistance value of 100 MΩ or more and less than 500 MΩ, and 12 individuals that exhibited a resistance value of 500 MΩ or more and less than 1000 MΩ, although they were determined to be good products. On the other hand, in the sample of the example, no individual showed a resistance value of 100 MΩ or more and less than 500 MΩ, and only three individuals showed a resistance value of 500 MΩ or more and less than 1000 MΩ. That is, 997 individuals out of 1,000 exhibited a resistance value of 1000 MΩ or more, and had extremely excellent insulation performance. Therefore, in the sample of the example using the dry laminate type film for the outer package 12, the adhesive layer 34 functions as a barrier layer according to the principle shown in FIG. 5B even if the fragments 41 of the positive electrode 4 exist in the outer package 12. Was confirmed.

=== Other Embodiments ===
The description of the above-described embodiments is for facilitating the understanding of the present invention, and does not limit the technical scope of the present invention in any way. The present invention can be modified and improved without departing from the spirit of the above embodiments, and the present invention includes equivalents thereof.

  The power storage element 1 according to the above-described embodiment is a lithium primary battery using the negative electrode lithium for the negative electrode 8, and has a structure without the negative electrode current collector 7 shown in FIGS. Since the negative electrode lithium has a property that it is difficult to be heat-welded to the heat seal layer 31 of the laminate film 13b, the exterior body 12 is heat-welded to the electrode body 2 with the laminate film 13a disposed on the positive electrode current collector 3 side. I was Of course, as long as the electrode body 2 has the negative electrode current collector (reference numeral 7 in FIG. 1B) on the negative electrode 8 side, the negative electrode 8 side may be thermally welded to the laminate film 13b.

  The electric storage element 1 according to the embodiment of the present invention includes a flat positive electrode 4 and a flat negative electrode 8 in a flat bag-shaped exterior body 12 made of a laminate film (13a, 13b) manufactured by a dry lamination method. Is not limited to a lithium primary battery as long as it is a power storage element 1 in which an electrode body 2 formed by stacking vertically is accommodated. Of course, the storage element 1 according to the embodiment may be a secondary battery, a battery provided with a polymer electrolyte instead of the electrolyte, or a battery provided with neither the electrolyte nor the separator 6 like an all-solid battery.

  In the energy storage device 1 according to the above embodiment, the adhesive layer 34 of the laminated film (13a, 13b) constituting the exterior body 12 insulates the metal foil 32 and the electrode body 2 when the heat seal layer 31 is broken. The thickness of the adhesive layer 34 can be changed as appropriate according to the specifications of the device in which the electric storage device 1 is incorporated and the use environment.

  The corners 10 of the electrode body 2 may be chamfered to prevent damage to the heat seal layer 31 due to the contact of the corners 10 of the electrode body 2.

  The electrode body 2 has a configuration in which one positive electrode 4 and one negative electrode 8 face each other via a separator 6 as one set of unit cells, and is stacked vertically so that a plurality of sets of unit cells are connected in series. May be done. The electrode body 2 composed of a plurality of unit cells connected in series may be housed in the single exterior body 12. However, a power supply for an electronic device such as an IC card whose thickness is regulated by a standard usually includes a “single-layer” power storage element having one positive electrode 4 and one negative electrode 8 as in the above-described embodiment. 1 is used. Then, in order to increase the capacity of the electric storage element 1, it is necessary to increase the planar size of the electrode body 2. Therefore, when the present invention is applied to a single-layer laminate type power storage element, a more special effect is achieved.

1,101 storage element, 2 electrode body, 3 positive electrode current collector, 4 positive electrode,
5 positive electrode material, 6 separator, 7 negative electrode current collector, 8 negative electrode,
9 negative electrode material, 12 exterior body,
13a, 13b, 113a, 113b laminated film,
14 peripheral region, 24 positive terminal plate, 28 negative terminal plate,
31 heat seal layer, 32 metal foil (base material), 33 surface layer, 34 adhesive layer,
41 fragments

Claims (6)

An electricity storage element in which an electrode body formed by vertically stacking a plate-shaped positive electrode and a plate-shaped negative electrode is housed in a flat bag-shaped exterior body made of a laminated film,
In the electrode body, a current collector is disposed on at least one of the uppermost layer and the lowermost layer,
In the exterior body, a laminate film facing the current collector is formed by laminating a heat seal layer on one main surface of a metal foil via an adhesive layer,
The outer package is formed by heat-welding a peripheral region of a laminated film laminated in a state where the heat seal layer faces each other in a vertical direction,
The electrode body is heat-welded to the heat seal layer while being disposed in a region surrounded by the peripheral region,
A power storage element characterized by the above-mentioned.   The energy storage device according to claim 1, wherein the laminate film includes the heat seal layer made of a modified polyolefin-based resin.   3. The power storage device according to claim 1, wherein the current collector thermally welded to the heat seal layer is made of austenitic stainless steel. 4.   4. The power storage device according to claim 1, wherein the power storage device includes only one of the sheet-shaped positive electrode and the sheet-shaped negative electrode. 5.   The power storage device according to any one of claims 1 to 4, further comprising a negative electrode made of lithium metal or a lithium alloy, wherein an indeterminate-shaped electrolyte is stored inside the exterior body, and a positive electrode current collector is provided. A power storage element, which is thermally welded to the heat seal layer. It is a manufacturing method of the electrical storage element in any one of Claims 1-5,
A step of disposing the electrode body between laminated films facing each other in the vertical direction, and thermally bonding the heat seal layer and the current collector by thermocompression bonding an arrangement area of the electrode body,
A sealing step of sealing the outer package by thermocompression bonding of a peripheral region of the laminate film facing in the vertical direction,
A method for manufacturing a power storage device, comprising:

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