JP2019057473A - Electrochemical cell - Google Patents

Abstract

To provide an electrochemical cell using a laminate film in an exterior package with a high capacity.SOLUTION: An electrochemical cell 1 includes: a pair of electrodes 5 and 6; a separator 7 separating the pair of electrodes 5 and 6; an electrolyte; and an exterior casing that is formed by laminate films 10 and 20 in which a heat-seal resin layer is formed onto a front surface of a metal foil, houses the pair of electrodes 5 and 6, the separator 7, and the electrolyte, and in which both heat-seal resin layers 13 and 23 are sealed in a weld part 4. A melting point of the separator 7 is higher than that of the heat-seal resin layers 13 and 23.SELECTED DRAWING: Figure 4

Description

The present invention relates to an electrochemical cell.

An electrochemical cell using a laminate film for the exterior body is lightweight and flexible. An electrode body produced by laminating or winding a pair of electrodes facing each other via a separator is accommodated in the exterior body. In particular, a thin electrochemical cell can be obtained by storing a pair of electrodes opposed via a separator in an exterior body made of a laminate film and sealing the outer periphery of the exterior body by thermal welding.

  On the other hand, in the case of such an electrochemical cell, the electrodes may be short-circuited if the position of the separator is shifted due to wind or static electricity during production, vibration or impact during use, and the like. For this reason, various methods for fixing the separator to the laminate film have been proposed (see, for example, Patent Document 1 and Patent Document 2).

JP 2010-277925 A JP-A-2005-71658

  In such an electrochemical cell, for example, a three-layer film of nylon-aluminum foil-polypropylene (melting point: 130 to 170 ° C.) may be used as a laminate film. When two laminate films are stacked and an electrode body including a separator made of polypropylene or polyethylene (melting point: 110 to 140 ° C.) is accommodated therein, heat is transferred to the separator when polypropylene on the outer periphery of the laminate film is thermally welded. The separator may contract and the cell may be short-circuited.

  For this reason, it is necessary to lengthen the distance to the welding part of a laminate film and a separator so that heat may not be transmitted to a separator. However, the longer this distance is, the smaller the electrode has to be and there is a problem that the capacity is reduced. This problem is particularly influential with smaller electric cells.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to increase the capacity of an electrochemical cell using a laminate film as an exterior body.

  As a result of intensive studies, the present inventor has focused on the fact that by using a separator having heat resistance against thermal welding, the influence of the thermal contraction of the separator during sealing can be suppressed as much as possible, and the electrode that can be accommodated in the exterior body can be maximized. The present invention has been achieved.

  That is, the electrochemical cell according to the present invention comprises a pair of electrodes, a separator separating the pair of electrodes, an electrolyte, and a laminate film in which a heat-fusible resin layer is formed on the surface of the metal foil, An exterior body that houses a pair of electrodes, the separator, and the electrolyte, and in which the heat-fusible resin layers are sealed in a welded portion, and the melting point of the separator is the heat-fusible resin layer It is characterized by being higher than the melting point of.

  In the electrochemical cell according to the present invention, it is more preferable that the separator is fixed to the heat-fusible resin layer, and the separator is sandwiched between the heat-fusible resin layers at the position of the welding portion. It is particularly preferred that

  According to the present invention, since the separator having a higher melting point than the heat-fusible resin layer on the cell inner surface side of the laminate film is used, even when the outer periphery of the laminate film is welded with heat, the separator shrinks very little. Or it will not shrink. The area of the separator needs to be larger than that of the electrode to prevent a short circuit. With this configuration, the opposing area of the electrode can be made as close as possible to the area of the separator, and the capacity can be increased.

  In addition, since the separator is fixed to the heat-fusible resin layer on the inner surface of the cell, in addition to the influence of wind and static electricity during cell manufacturing, the separator will be displaced even if vibration or impact is applied to the assembled cell. There is no. Since the heat-fusible resin layer is melted by heating and bonded to the surface and holes of the separator, the separator is fixed, so there is no need to use a separate bonding material.

  In particular, when the separator is sandwiched between the welded portions of the laminate film, the area to be fixed increases and the separator can be firmly fixed. In addition, the electrode can be further increased with respect to the size of the separator, and the capacity is more preferable.

  In the electrochemical cell according to the present invention, the separator is made of one or more materials selected from polytetrafluoroethylene, polyacrylonitrile, polyphenylene sulfide, polyether ether ketone, glass fiber, polyamide, and cellulose. .

  According to the present invention, since these materials are used for the separator, the melting point of the separator is sufficiently higher than that of the heat-fusible resin layer, so that the separator shrinks very little or does not shrink. Thereby, an electrode can be made wide and a capacity | capacitance can be enlarged.

  In the electrochemical cell according to the present invention, at least one of the pair of electrodes is electrically connected to the exposed portion of the metal foil.

  According to the present invention, an electrode can be collected without using a current collector made of a thin metal plate. In addition, the electrode is arrange | positioned in the location in which the heat-fusible resin layer of a laminate film is not formed. Thereby, an electrode can be enlarged by the thickness of a collector and a heat-fusible resin layer, and the capacity | capacitance of a cell can be enlarged. Furthermore, since the metal foil of a laminate film can be used for the terminal for connecting to an external apparatus, it can be set as an inexpensive electrochemical cell with few parts.

  According to the present invention, the heat shrinkage of the separator can be suppressed as much as possible by the heat at the time of sealing the laminate film. Thereby, an electrode can be made wide and a high capacity | capacitance electrochemical cell can be provided.

It is a top view of the electrochemical cell of this invention. It is an expanded sectional view in the AA section of the electrochemical cell of the present invention. It is a top view of the electrochemical cell of this invention. It is an expanded sectional view in the BB section of the electrochemical cell of the present invention. It is a top view of the electrochemical cell of this invention. It is an expanded sectional view in CC section of the electrochemical cell of the present invention.

  Embodiments of the electrochemical cell of the present invention will be described below, and each configuration will be described in detail with reference to the drawings. In the following embodiments, an electric double layer capacitor will be described as an example of an electrochemical cell, but is not limited thereto. Examples of the electrochemical cell include a lithium ion secondary battery and a lithium ion capacitor. In each of these electrochemical cells, the same effects as those of the present application can be achieved in the same manner as the electric double layer capacitor.

(First embodiment)
Examples of embodiments of the electrochemical cell of the present invention are shown in FIGS. FIG. 1 is a plan view of an electrochemical cell using an embodiment of the present invention. 2 is a cross-sectional view taken along a chain line AA shown in FIG.

  As shown in FIG. 1, the electrochemical cell 1 in the present embodiment includes an electrode, an electrolyte, a separator, and the like inside a thin package body that is rectangular in plan view and has a long side cell length L. It has a structure in which a power storage element is accommodated. Two terminals 2 electrically connected to a pair of electrodes composed of a positive electrode and a negative electrode are drawn from the inside of the electrochemical cell 1 to the outside.

  In this embodiment, as a material for the exterior body, two laminated films are sealed at the position of the weld portion 4 by thermocompression bonding. Thereby, the penetration | invasion of the external gas and the water | moisture content to the inside of the electrochemical cell 1 can be prevented. Further, the terminal 2 is sandwiched between two laminated films while being protected by the sealant 3, and is integrally sealed from above by thermocompression bonding.

  In the present embodiment, the shape of the electrochemical cell 1 is a rectangular shape in plan view. However, by making the two laminate films used as the exterior body into an arbitrary shape, a square shape, other polygonal shape, and circular shape in a plan view. Various cell shapes such as an elliptical shape and a star shape can be used. In addition to forming the exterior body by superimposing two laminate films, the power storage element can be housed inside the exterior body in which one laminate film is folded in half. In this case, it is not necessary to perform thermocompression bonding on one side of the rectangle of the exterior body, which is preferable because the influence of heat can be suppressed.

Next, the present embodiment will be described in detail with reference to FIG.
FIG. 2 is an enlarged cross-sectional view in which the vicinity of the welded portion 4 where the terminal 2 is located is enlarged among the cross-section at the position AA in FIG. The two laminated films 10 and 20 described above respectively face the heat resistant resin layers 11 and 21 facing the outside of the electrochemical cell 1, the metal foils 12 and 22 as core materials, and the internal space of the electrochemical cell 1. The heat-fusible resin layers 13 and 23 are constituted by three layers. In the present invention, the heat-fusible resin layers 13 and 23 of the laminate films 10 and 20 face each other and are thermocompression bonded at the position of the welded portion 4 in FIG.

  In the present invention, a pair of electrodes 5 and 6 are housed in an internal space formed from the laminate films 10 and 20 at a position inside the welded portion 4 in a plan view. The pair of electrodes 5 and 6 face each other with a separator 7 interposed therebetween. The pair of electrodes 5 and 6 are formed on current collectors 8 and 9 made of metal foil, respectively, for current collection. Among these, one of the two terminals 2 is joined to one current collector 8 by ultrasonic welding or the like, and is drawn out of the electrochemical cell 1. Although not shown, the other current collector 9 is also connected to the other of the two terminals 2 by ultrasonic welding or the like at a position of another cross section in FIG. 1 and pulled out of the electrochemical cell 1. ing.

  These two terminals 2 are sandwiched between the laminate films 10 and 20 at the position of the weld portion 4 shown in FIG. At this time, since the metal terminal 2 and the heat-fusible resin layers 13 and 23 of the laminate films 10 and 20 in contact with the metal terminal 2 have poor bonding properties, the exterior body cannot be sufficiently sealed by thermocompression bonding. . For this reason, by forming the sealant 3 around the terminals 2, the sealant 3 is melted at the time of thermocompression bonding and protrudes from the welded portion 4 to the outside, whereby the welded portion 4 having high airtightness can be obtained.

  Here, the laminated films 10 and 20 constituting the outer package of the electrochemical cell 1, the pair of electrodes 5 and 6, the current collectors 8 and 9, the separator 7, the terminal 2, and the sealant 3 are respectively shown in FIG. This will be described in detail with reference to FIG.

  As shown in FIG. 1, L is the total length of the cell including the terminal 2 in the direction of one side where the terminal 2 of the electrochemical cell 1 is formed. Further, as shown in FIG. 2, the length of the terminal 2 where the sealant 3 is not formed around is L1, the length of the terminal 2 where the sealant 3 is formed around is L2, and the length of the welded portion 4 is L3, the length from the welded portion 4 to the current collectors 8 and 9 is defined as L4, the current collectors 8 and 9 where the electrodes 5 and 6 are not formed are defined as L5, and the electrode length is defined as L6. .

  The separator 7 is formed larger than the current collectors 8 and 9 in order to prevent the pair of electrodes 5 and 6 and the current collectors 8 and 9 from coming into contact with each other and short-circuiting. On the other hand, in the case of a size close to the welded portion 4, it is easily affected by heat when the laminated film is thermocompression bonded.

  When performing thermocompression bonding, the heater temperature is generally heated for several seconds within a temperature range between the melting point of the heat-fusible resin layer and the melting point of the heat-fusible resin layer + about 50 ° C. The heat at the time of welding is transmitted to the separator 7. If a low-melting-point material such as polyolefin is used as the material of the separator 7 as in the prior art, the separator 7 contracts from the outer periphery. When the separator 7 contracts to the positions of the current collectors 8 and 9 and the pair of electrodes 5 and 6, the positive electrode and the negative electrode are short-circuited. For this reason, when a low melting point separator is used as in the prior art, the length L4 from the welded portion 4 to the current collectors 8 and 9 has to be increased.

  On the other hand, in the electrochemical cell 1 of the present invention, the separator 7 having a melting point higher than that of the heat-fusible resin layers 13 and 23 of the laminate films 10 and 20 is used. For this reason, even if the separator 7 is close to the welded portion 4, the influence of the heat received during the thermocompression bonding is negligible, and the separator is not contracted or is minimal if any. Therefore, the length L4 from the welded portion 4 to the current collectors 8 and 9 can be made sufficiently short. Since the electrode length L6 of the pair of electrodes 5 and 6 can be increased without changing the cell length L, the capacity of the electrochemical cell 1 can be increased.

  In the present embodiment, the separator 7 is fixed to the heat-fusible resin layers 13 and 23 of the laminate films 10 and 20. Specifically, in the example shown in FIG. 2, the separator 7 is fixed to the heat-fusible resin layer 23 of the laminate film 20 at the position of the fixing portion 30. Thereby, the separator 7 is not displaced by wind or static electricity at the time of manufacturing the electrochemical cell 1 or by vibration or impact applied to the cell.

  The fixing portion 30 is formed by the heat-fusible resin layer 23 of the laminate film 20 being melted by heat and contacting and joining the separator 7. As an example of a method for forming the fixing portion 30, for example, the separator 7 is placed on the heat-fusible resin layer 23 of the laminate film 20, and a heater is applied on the separator 7 to form the heat-fusible resin layer 23. It can be melted. At this time, the heat-fusible resin layer 23 becomes the fixed portion 30 by joining to the surface and holes of the separator. Accordingly, the heat-fusible resin layer 23 of the laminate film 20 can be used as a bonding material, and it is not necessary to use an additional bonding material, which is preferable.

  As described above, the laminate films 10 and 20 in the present embodiment have the heat-resistant resin layers 11 and 21 on one surface of the metal foils 12 and 22 as the core material, and the heat-fusible resin layer 13 on the other surface. It is comprised with the film of the 3 layer structure in which 23 was formed.

  The metal foils 12 and 22 can be appropriately selected according to the types of electrodes and electrolytes constituting the electrochemical cell 1. In particular, as the metal foils 12 and 22, it is preferable to use a material having good conductivity, strength, durability, and corrosion resistance. Specifically, it can be composed of one or more selected from silver, copper, gold, aluminum, magnesium, zinc, nickel, iron, platinum, tin, titanium, and stainless steel.

The heat-fusible resin layers 13 and 23 are, for example, polypropylene (melting point: 130 to 170 ° C.), polyethylene (melting point: 110 to 140 ° C.), polystyrene (melting point: 240 ° C.), styrene / acrylonitrile copolymer (melting point: 115 ° C.), etc. These thermoplastic resins can be mentioned.
As the heat resistant resin layers 11 and 21, a resin having a melting point higher than that of the resin constituting the heat-fusible resin layer is used. Thereby, even if it heat-seals on a heat resistant resin layer, it does not melt. Examples of the material constituting the heat resistant resin layers 11 and 21 include polyamide, polyester, polybutylene terephthalate, polyethylene terephthalate, and nylon.

  If the total thickness of the laminate film is about 30 to 150 μm, a thin cell module can be constituted while maintaining gas barrier properties, and more preferably 50 to 120 μm. Moreover, the thickness of the heat-fusible resin layer, the metal foil, and the heat-resistant resin layer is preferably about 10 to 50 μm.

  In the present embodiment, the separator 7 has higher heat resistance than the heat-fusible resin layers 13 and 23 of the laminate films 10 and 20. Specifically, it is preferable to have a melting point higher than that of the heat-fusible resin layers 13 and 23 of the laminate films 10 and 20.

  Examples of the material constituting the separator 7 include polytetrafluoroethylene (melting point: 327 ° C.), polyacrylonitrile (melting point: 317 ° C.), polyphenylene sulfide (melting point: 280 ° C.), polyether ether ketone (melting point: 350 ° C.), glass fiber ( And a microporous film or a nonwoven fabric made of a material such as polyamide and cellulose.

  For example, when polypropylene having a melting point of 160 ° C. is used for the heat-fusible resin layer, it is preferable to use polytetrafluoroethylene having a melting point of 327 ° C. for the separator.

  The terminal 2 is required to have sufficient corrosion resistance in the internal space in addition to conductivity. Further, since the terminal 2 is joined to the current collectors 8 and 9 by ultrasonic welding or the like, it is required to be a material that can be easily joined. In this embodiment, when it is set as the structure of an electrical double layer capacitor as the electrochemical cell 1, both the terminal 2 and the collectors 8 and 9 can use aluminum or aluminum alloy, for example.

  When the electrochemical cell 1 is configured as an electric double layer capacitor, activated carbon can be used as the active material for the electrodes 5 and 6. The activated carbon, a conductive assistant made of graphite and the like and a resin binder are mixed to form a sheet, and then bonded onto the current collectors 8 and 9 using a conductive adhesive. On the other hand, the electrodes 5 and 6 may be formed on the current collectors 8 and 9 by applying a slurry paste obtained by further adding an organic solvent to the mixture onto the current collectors 8 and 9 and drying the paste. As the active material, in addition to activated carbon, various carbon-based materials, conductive polymers, and the like can be used.

  As an electrolyte used for the electric double layer capacitor, an electrolytic solution in which a supporting salt having ionic conductivity is dissolved in a nonaqueous solvent can be used. Moreover, an ionic liquid, a solid electrolyte, or the like may be used as the electrolyte, and is appropriately selected so as to meet the electrical characteristics and long-term reliability required for the cell.

(Second embodiment)
Examples of other embodiments of the electrochemical cell 1 of the present invention are shown in FIGS. FIG. 3 is a plan view of the electrochemical cell 1 of this embodiment. 4 is a cross-sectional view taken along the chain line BB shown in FIG.

  In this embodiment, in the internal space of the exterior body, the laminate film is in a state in which the metal foil is exposed on the internal surface by lacking a part of the heat-fusible resin layer constituting the laminate film. In the present embodiment, the metal foil exposed in the internal space is used as a current collector. Furthermore, the metal foil of the laminate film exposed outside the exterior body is used as a terminal. With this configuration, the number of parts of the electrochemical cell can be reduced and the capacity can be increased.

  FIG. 3 shows a plan view of the electrochemical cell 1. For the sake of explanation, this electrochemical cell 1 has, for example, a rectangular shape in plan view, in which the long side cell length is the same L as the electrochemical cell 1 shown in FIG. Further, similarly to the electrochemical cell 1 shown in FIG. 1, two laminate films are sealed by thermocompression bonding at the position of the weld portion 4 as the material of the outer package. The electrochemical cell 1 shown in FIG. 1 has a structure in which the terminal 2 is drawn from the inside of the cell, whereas in this embodiment, the metal foil is electrically connected to the positive electrode and the negative electrode pair. 12 and 22 are used as terminals.

  Next, the present embodiment will be further described in detail with reference to FIG. Here, for comparison with the first embodiment, the same reference numerals are used for the members to be used and will be described below. The metal foil 12 of the laminate film 10 is exposed to the outside of the cell and functions as a terminal at the position of the chain line BB in plan view shown in FIG. Although not shown, the metal foil 22 of the laminate film 20 is also exposed to the outside of the cell and functions as a terminal at another position in plan view.

  In this embodiment, the current collectors 8 and 9 in the first embodiment are not provided, and the pair of electrodes 5 and 6 are connected to the metal foils 12 and 22 of the laminate films 10 and 20 exposed inside the exterior body, respectively. ing. Further, the metal foils 12 and 22 also function as terminals. Thereby, an electrode and the exterior can be electrically connected, without using the terminal 2 of another member like 1st embodiment. Moreover, since there is no location which joins a collector and a terminal like 1st embodiment, an electrode can be arrange | positioned to this location.

  In the present embodiment, the separator 7 is disposed so as to be sandwiched between the heat-fusible resin layers 13 and 23 of the laminate films 10 and 20. By arrange | positioning in this way, the separator 7 can be fixed more reliably. In the present invention, since the melting point of the separator 7 is higher than the melting points of the heat-sealing resins 13 and 23, even if the separator 7 is sandwiched between the welded portions 4, the influence of the heat received during the thermocompression bonding is negligible. The separator does not shrink, or even very little, if any.

  When the separator 7 is sandwiched between the heat-fusible resin layers 13 and 23, the separator 7 is disposed between the laminate film 10 to which the electrode 5 is fixed and the laminate film 20 to which the electrode 6 is fixed. 20 can be heat-welded. At that time, when the separator 7 is temporarily fixed to one of the heat-fusible resin layers 13 and 23 of the laminate films 10 and 20 and then the laminate films 10 and 20 are thermally welded together, the position shift of the separator 7 is prevented. Is preferable. Temporary fixing can be performed by melting the heat-fusible resin layer of the laminate film using a heater or a soldering iron and bonding it to the separator. Although not shown, the separator 7 can be fixed to any one of the heat-fusible resin layers 13 and 23 and bonded by applying a heater, as in the first embodiment.

  In the present embodiment, by adopting the configuration as described above, L4 can be formed sufficiently short because there is no influence of heat on the separator 7 as in the first embodiment. In addition, since the sealant 3 for improving airtightness is not required as compared with the first embodiment, the distance L2 as shown in FIG. Further, since the junction between the current collector and the terminal becomes unnecessary, the distance L5 as shown in FIG. Therefore, the present embodiment can further increase L6 by the amount of these distances as compared with the first embodiment, and can increase the capacity because the electrode can be formed larger.

  Furthermore, in this embodiment, since there is no separate terminal 2 and sealant 3 formed around the terminal 2, the thickness of the welded portion 4 is uniform over the entire circumference. For this reason, the heat-welding resin can be uniformly dissolved during the heat-welding, and the leakage of the electrolytic solution can be prevented.

(Third embodiment)
The example of other embodiment of the electrochemical cell 1 of this invention is shown in FIGS. FIG. 5 is a plan view of the electrochemical cell 1 of this embodiment. FIG. 6 is a cross-sectional view taken along the chain line CC shown in FIG.

  In the first embodiment and the second embodiment described above, the configuration in which the pair of electrodes is disposed on each side of the two laminate films 10 and 20 and the separator is disposed therebetween is described. On the other hand, in this embodiment, a pair of electrodes formed by coating or the like on a metal foil are stacked via a separator, and an electrode body formed by folding, winding, or the like is accommodated in an exterior body. The case will be described.

  As shown in FIG. 5, in this embodiment, like the second embodiment, the electrochemical cell 1 having a rectangular shape in plan view with a long side cell length of L is used, and two laminated films are used as the material of the outer package. Is sealed by thermocompression bonding at the position of the welded portion 4.

  Moreover, as will be described later, the metal foils 12 and 22 constituting the laminate film are electrically connected to the positive electrode and the negative electrode pair, respectively, and are also used as terminals. On the other hand, although not shown, a configuration using two terminals that are electrically connected to a pair of electrodes as in the first embodiment may be employed.

Next, the present embodiment will be described in more detail with reference to FIG. 6 which is an enlarged cross-sectional view at the position of the chain line CC in FIG.
In the structure shown in FIG. 6, the electrode 5 formed on the current collector 8 and the electrode 6 formed on the current collector 9 are stacked via a separator 7. The electrode body is formed by being bent at the position. A current collector 8 electrically connected to the electrode 5 is connected to the metal foil 12 of the laminate film 10. Further, the current collector 9 electrically connected to the electrode 6 is connected to the metal foil 22 of the laminate film 20, while being insulated from the laminate film 10 by the heat-fusible resin layer 13.

In the present embodiment, like the second embodiment, the metal foil 12 is exposed to the outside of the cell and functions as a terminal at the position of the chain line CC in the plan view shown in FIG. Although not shown, the metal foil 22 is also exposed to the outside of the cell and functions as a terminal at another position in plan view.
In this embodiment, the two end portions of the separator 7 are fixed at the position of the welded portion 30 by being welded to the heat-fusible resin layers 13 and 23 in the manner described in the first embodiment. Has been. Although not shown, one end of the separator 7 whose position does not interfere with the current collector 8 is sandwiched between the two heat-fusible resin layers 13 and 23 as in the second embodiment. It can also be arranged.

  Also with such a configuration, since there is no influence of heat on the separator 7, L4 can be formed sufficiently short. Thereby, the electrode length L6 can be increased. About this embodiment, in addition to preventing the thermal contraction of the separator 7 at the time of sealing the exterior body and increasing the capacity, it is possible to increase the electrode area. Can be used. In addition, when combined with a configuration in which the metal foil of the laminate film is used as a terminal as in the second embodiment, the capacity can be further increased and the sealing performance can be improved.

  Hereinafter, in order to describe the electrochemical cell of the present invention in more detail, the electrochemical cell 1 shown in FIGS. 3 and 4 as described in the second embodiment is taken as an example, and its production process and examples are described. This will be specifically described. Needless to say, the present invention is not limited to this example, and based on this example and technical common sense, an electrochemical cell having the configuration of another embodiment can be manufactured.

  First, two laminate films 10 and 20 constituting the exterior body of the present invention were produced as follows. Hereinafter, the laminate film 10 will be described as an example, but the same applies to the laminate film 20.

  Specifically, first, masking was performed by sticking an adhesive tape in advance on the surface of the metal foil 12 made of an aluminum foil having a thickness of 40 μm at an exposed portion inside the outer package or a portion functioning as a terminal. Next, the heat-resistant resin layer 11 made of a nylon film having a thickness of 25 μm was bonded to one surface of the metal foil, and the heat-fusible resin layer 13 made of a polypropylene film having a thickness of 30 μm was bonded to the other surface and dried. Then, the part which stuck the adhesive tape was cut | disconnected with the blade, and a part of metal foil 12 was exposed to the surface by peeling a nylon film and a part of polypropylene film with the adhesive tape. And it cut | disconnected to the predetermined dimension and produced the two laminated films 10. FIG.

  Next, the electrodes 5 and 6 were produced as follows. First, a conductive assistant made of activated carbon powder, a carbon material, and a resin binder were mixed and pressed to form a sheet having a thickness of 0.15 mm. And this electrode 5 and 6 was obtained by cut | disconnecting this sheet-like electrode to the rectangle of 21 mm x 8 mm. The electrodes 5 and 6 were placed on the exposed portions of the metal foils 12 and 22 of the laminate films 10 and 20, respectively, adhered with a conductive adhesive, and then dried.

  Next, a separator 7 made of a polytetrafluoroethylene microporous film was cut on the electrode 6 to 25.5 mm × 12.5 mm, and temporarily fixed to the heat-fusible resin layer 23 using a soldering iron. Then, the laminate films 10 and 20 were overlapped, and among the four sides of the welded portion 4, first, three sides were heat sealed. L4 at this time was 1.5 mm. The heat sealing conditions were 180 ° C. and 3 seconds.

  Next, after drying this assembly, an electrolytic solution in which an ion conductive supporting salt was dissolved in a non-aqueous solvent was injected under a low dew point environment. Then, the remaining one side of the welded portion 4 was similarly heat-sealed under the same conditions as the above-mentioned heat seal, and an electric double layer capacitor having an outer shape of 30 mm × 15 mm and a thickness of 0.5 mm was produced.

DESCRIPTION OF SYMBOLS 1 ... Electrochemical cell 2 ... Terminal 3 ... Sealant 4 ... Welding part 5, 6 ... Electrode 7 ... Separator 8, 9 ... Current collector 10, 20 ... Laminate film 11, 21 ... Heat-resistant resin layer 12, 22 ... Metal foil 13, 23 ... Heat-sealable resin layer 30 ... Fixed part

Claims (5)

A pair of electrodes;
A separator that separates the pair of electrodes;
Electrolyte,
It consists of a laminate film with a heat-fusible resin layer formed on the surface of a metal foil, contains the pair of electrodes, the separator, and the electrolyte, and the heat-fusible resin layers are sealed at the welded portion. And an exterior body,
The electrochemical cell, wherein the melting point of the separator is higher than the melting point of the heat-fusible resin layer.   The electrochemical cell according to claim 1, wherein the separator is fixed to the heat-fusible resin layer.   The electrochemical cell according to claim 2, wherein the separator is sandwiched between the heat-fusible resin layers at the position of the weld portion.   The separator is made of one or more materials selected from polytetrafluoroethylene, polyacrylonitrile, polyphenylene sulfide, polyether ether ketone, glass fiber, polyamide, and cellulose. The electrochemical cell according to one item.   The electrochemical cell according to any one of claims 1 to 4, wherein at least one of the pair of electrodes is electrically connected to an exposed portion of the metal foil.

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