JP2005093825A - Flat plate type electrochemical cell - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a high-reliability flat plate type electrochemical cell which is easily made high in energy density, small-sized and thin and free of a defect in connection with a collector due to deformation and breakage of a lead terminal. <P>SOLUTION: Employed is a structure provided with a protection frame protecting an external lead terminal led out of a sealing body of an exterior body. Namely, an electrochemical cell having an electrochemical cell element which is carried on a metal pyroelectric body and has at least a couple of electrodes functioning as positive or negative electrodes and an ion conductive electrolyte, the bag-shaped exterior body which is formed of a resin film or a laminate film of resin and metal foil and in which the electrochemical cell is stored inside and hermetically sealed, and a couple of metal leads for electrically connecting the couple of electrodes of the electrochemical cell element to an external circuit is in such a structure that tip parts of the metal leads are held or protected by a protection frame part constituted by leading at least of one of the gold leads out of the cell from the sealing part of the exterior body and extending the exterior body from a peripehral edge of the sealing part. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a chemical battery such as an alkaline battery, a lithium battery or a lithium ion battery, and an electrochemical cell such as an electric double layer capacitor, and in particular, an external lead for electrically connecting the electrochemical cell and an external circuit. The present invention relates to the structure of the terminal and its peripheral part.

  In recent years, in response to the miniaturization and high-density mounting of portable electronic devices, there has been a demand for small, thin, light, and high energy density for electrochemical cells such as batteries and electric double layer capacitors as power supply elements used in them. It has been. As a method for realizing a reduction in size, thickness and weight of such an electrochemical cell, an electrochemical cell comprising a power generation element or a storage element in a bag-like outer package made of a resin film or a laminate film of a metal foil and a resin film. A flat plate electrochemical cell having a structure in which an element is housed and an opening at a peripheral edge of an outer package is hermetically sealed with heat seal or an adhesive has been proposed and partially put into practical use.

Conventionally, this type of flat plate electrochemical cell has been made with the configuration shown in FIG. The electrode composed of the positive electrode 1 and the negative electrode 2 is composed of an electrode active material, a conductive agent such as carbon for imparting conductivity, and a binder such as a resin, and is made of metal foil, net, expanded metal or punched metal. Alternatively, they are placed on or integrally laminated on the positive electrode current collector 3 and the negative electrode metal current collector 4 made of a conductive polymer film containing a conductive filler such as carbon. After the flat electrochemical cell is assembled, the positive electrode metal lead 5 and the negative electrode metal lead 6 are welded to the positive electrode current collector and the negative electrode metal current collector, respectively, in order to electrically connect the electrodes in the cell and the external circuit. They are connected by caulking or the like by eyelets (see, for example, Patent Documents 1 and 2). A pair of electrodes laminated with a separator 7 made of a polymer porous film, nonwoven fabric or papermaking, or a pair of striped electrodes and separators laminated in this manner are wound into a flat shape or a cylindrical shape. The electrode body 8 that has been pressed into a flat plate shape is accommodated in the exterior body 9. The electrode body 8 is impregnated and occluded with an ionic conductive electrolyte after or before being housed in the exterior body 9 to constitute an electrochemical cell. When a solid electrolyte such as a gel electrolyte, a polymer solid electrolyte, or an inorganic solid electrolyte is used as the electrolyte, these solid electrolytes are used alone or in combination with a separator. The exterior body 9 is made of a resin film or a laminate film of the resin films 9a and 9c and the metal foil 9b, and an electrochemical cell element made of the electrode body and the electrolyte is housed inside the bag in a bag shape. The peripheral portion is hermetically sealed by heat sealing, pressure bonding, adhesive, or the like. When the electrode body is housed, the metal external lead terminal is housed and sealed in a state where one end is drawn out across the sealing portion at the peripheral edge of the exterior body (see, for example, Patent Document 2).
JP-A-9-283100 (page 1-4, FIGS. 2, 3) Japanese Patent Application Laid-Open No. 11-345599 (page 2-5, FIG. 1)

  In a conventional flat type electrochemical cell, an external lead terminal that electrically connects an electrode body (electrochemical cell element) housed in an exterior body and an external circuit has a pair of metal leads at the periphery of the exterior body. Because it is a structure that is just pulled out from the sealing part, it is necessary to place a manual, tool, conveyor belt, measuring machine terminal in the lead part during the inspection process after cell assembly, transportation, packaging, installation in equipment, mounting, etc. However, there are problems that the lead part is deformed, bent or bent when it comes into contact with a container, parts on the substrate, etc., and is damaged due to damage or the like. In particular, in the flat type electrochemical cell, it is necessary to make the external lead terminal thin as well as the cell body, and since it uses a thin plate or foil-like metal, the strength is insufficient and the above inspection process, transportation, packing, equipment etc. There is a large problem of shape deformation and breakage in the process of mounting, mounting, etc., and even after mounting on equipment, the lead part is broken or damaged due to vibration or impact, etc. there were.

  Also, as the external lead terminal, a plate-like, rod-like or wire-like metal lead member is prepared separately from the current collector, and this is welded to the part where the electrode material of the current collector is not disposed (I) , Stick or glue. Alternatively, (II) connection and fixing are performed by, for example, caulking by passing a grommet or the like through a portion where the electrode material is disposed. In these methods, since the current collector and the metal lead terminal can be manufactured separately, each part manufacturing itself, such as the integral formation of the electrode on the current collector, is efficient, but (A) the lead terminal and the current collector The extra manufacturing process is required to connect the body by welding, etc., and the efficiency of the entire manufacturing process is low. (B) The thickness of the manufactured flat plate electrochemical cell is connected to the thickness of lead terminals and eyelets, etc. It becomes thick due to warping and distortion of the part, which is disadvantageous in realizing a small size, thinning, and high energy density. (C) Contact failure between the lead terminal and the current collector and the lead terminal coming off the current collector There has been a problem such as the occurrence of defects due to the above.

  In order to solve the above-described problems, the flat plate electrochemical cell of the present invention has a structure in which a protective frame for protecting the external lead terminal drawn out from the sealing portion of the outer package is provided. That is, a metal current collector, a pair of electrodes supported on the metal current collector and functioning as a positive electrode or a negative electrode, an ion conductive electrolyte, a metal current collector, an electrode, and an electrolyte are housed inside and hermetically sealed. An exterior body to be stopped and a metal lead for electrically connecting the electrode and the external circuit are provided, and the metal lead is held by the exterior body and the protective frame portion.

  With this structure, the periphery of the exposed portion of the metal lead serving as the external lead terminal is surrounded by the sealing portion and the protective frame portion of the exterior body, so it is sufficient even if the thickness of the metal lead and the metal current collector is reduced. Mechanical strength and electrical connection leads can be obtained, and defects due to deformation, bending, breakage, breakage, etc. of metal leads do not occur, and a flat and thin flat electrochemical cell can be easily obtained.

  Further, in the assembly process of the electrochemical cell and the mounting process of the electrochemical cell to the device used, the leading end of the metal lead drawn out from the protective frame part and the sealing part of the exterior body is the sealing part of the exterior body or The structure is characterized in that it is cut and removed at a protective frame portion around the sealing portion or a predetermined portion near the inner line portion of the protective frame. As a result, the metal lead is protected and fixed by the protective frame until immediately before mounting and mounting on the equipment to be used, so the above-mentioned cell assembly process and post-assembly inspection process, transport, packing, transportation, and mounting to the equipment There is an advantage that a flat electrochemical cell that is smaller, thin, and highly reliable can be obtained more easily without occurrence of defects due to deformation or breakage of the metal lead in the process of mounting or the like.

Further, a metal was used as the current collector, and a part of the metal current collector was extended and the one directly drawn out from the sealing portion of the outer package was used as an external lead terminal. That is, a metal current collector, a pair of electrodes supported on the metal current collector and functioning as a positive electrode or a negative electrode, an ion conductive electrolyte, a metal current collector, an electrode, and an electrolyte are housed and hermetically sealed. And a metal current collector that is held by the exterior body and a protective frame, and is electrically connected to an external circuit by the metal current collector.
The thickness of the metal lead may be the same as that of the current collector, and the lead part outside the sealing part and the outer package may be thick or thin. With this configuration, the step of connecting the lead terminal and the current collector becomes unnecessary, the problems (A) to (B) are solved, and it is easy to reduce the size and thickness, and the highly reliable flat plate electrochemical The cell can be easily manufactured.

  According to the present invention, the periphery of the exposed portion of the metal lead serving as the external lead terminal is surrounded by the sealing portion of the exterior body film and the protective frame portion in which the sealing portion is extended. Even if the thickness is reduced, sufficient mechanical strength and electrical connection leads can be obtained, and metal leads can be deformed, bent, broken, broken, etc., and not flattened. A chemical cell is easily obtained.

  Further, in the assembly process of the electrochemical cell and the mounting process of the electrochemical cell to the device used, the leading end of the metal lead drawn out from the protective frame part and the sealing part of the exterior body is the sealing part of the exterior body or The structure was cut and removed at a protective frame portion around the sealing portion or a predetermined portion near the inner line portion of the protective frame. As a result, the metal lead is protected and fixed by the protective frame until immediately before mounting and mounting on the equipment to be used, so the above-mentioned cell assembly process and post-assembly inspection process, transport, packing, transportation, and mounting to the equipment In addition, there is no occurrence of defects due to deformation or breakage of the metal lead in the process of mounting or the like, and a smaller, thinner and more reliable flat plate electrochemical cell can be obtained more easily.

  Further, a part of the metal current collector is extended, and the one directly drawn out from the sealing portion of the outer package is used as the external lead terminal. This eliminates the need for (A) an extra step of connecting the metal lead and the current collector by welding or the like, so that the production efficiency is high, and (B) the thickness of the lead terminal and the eyelet and the warp or distortion of the connecting portion. Due to this, there is no increase in cell thickness, the cell can be made small and thin easily, and it has a higher energy density. (C) Due to poor contact between the metal lead and current collector connection or disconnection of the metal lead. The occurrence of such defects can be reduced, and a more reliable flat plate electrochemical cell can be obtained.

  Hereinafter, the best mode for carrying out the present invention will be described with reference to the drawings.

  FIG. 1 is a cross-sectional view of a flat plate electrochemical cell using the present invention. The electrodes composed of the positive electrode 1 and the negative electrode 2 are each composed of a mixture of an electrode active material and a conductive agent such as carbon and a binder such as a resin for imparting conductivity, if necessary, a metal foil, a plate, The positive electrode metal current collector 3 and negative electrode metal current collector 4 made of a net, an expanded metal, a punched metal, or the like are placed or integrally laminated. The positive electrode metal current collector 3 and the negative electrode metal current collector 4 are respectively provided with a positive electrode metal lead 5 and a negative electrode metal lead 6 for electrically connecting the in-cell electrode and an external circuit. This metal lead leaves an exposed portion of a metal current collector that does not form an electrode when forming an electrode layer on the metal current collector, and is a metal foil or plate prepared by punching in a predetermined lead shape in advance there. A lead made of a net or wire is fixed by welding or the like.

The material of the metal current collector and the metal lead may be any material that is chemically stable with respect to the electrolyte and electrode material described later, electrochemically stable with respect to charging and overdischarge, and has corrosion resistance. Copper, nickel, stainless steel and the like are preferable. A belt-like laminate laminated between the positive electrode 1 and the negative electrode 2 via the separator 7 is wound into a flat shape or a cylindrical shape, and pressed to be formed into a flat plate shape, whereby an electrode body 8 is obtained. The electrode body 8 is dried at a predetermined temperature if necessary, and is stored in the exterior body 9. The exterior body 9 is made of a resin film or a laminate film of a resin and a metal foil, and the electrode body 8 and an electrolyte described later are housed inside the film in a bag shape so that the metal lead protects the exterior body 9 Positioning is performed so as to be sandwiched between the frame portions 11. The peripheral part of the exterior body film is hermetically sealed by heat sealing, pressure bonding, bonding with an adhesive, or the like. When the electrode body is stored, the positive electrode metal lead 5 and the negative electrode metal lead 6 are stored and sealed in a state where one end is pulled out across the sealing portion 12 at the peripheral edge of the exterior body 9. 4 and 5 are plan views of a flat plate electrochemical cell using the present invention. A protective frame 11 is provided on the outer peripheral edge of the sealing portion 12 on the side from which the metal lead is drawn, and the tip of the metal lead drawn from the sealing portion is protected when the outer peripheral edge of the outer body is sealed. It is sandwiched between the upper and lower films of the frame portion to be protected or held. Protection of the metal lead tip by the outer frame film of the protective frame part may be protected by sandwiching it between the upper and lower protective frame part films, but the metal lead is adhered and fixed to the film of the protective frame part. Adhesive fixing is preferable because lead misalignment, deformation, and breakage are more reliably prevented. Moreover, although the film of a protective frame part may be only an upper surface or a lower surface, since both upper and lower surfaces are protected more reliably, it is preferable. This adhesive fixing part 13 can be thermocompression-bonded (heat-seal), pressure-bonded, or bonded by an adhesive as with the sealing part, but a thermoplastic resin such as a polyolefin resin is used as the resin inside the exterior body film. In this case, it is particularly preferable because it can be bonded and fixed by thermocompression bonding in the same manner as the heat seal of the sealing portion, is efficient, and high adhesive strength can be obtained.
If there is a space in the equipment used and the plate electrochemical cell can be mounted on the equipment used with a protective frame, by using the metal lead between the sealing part 12 and the protective frame part 11 as an external lead terminal, Can be used with a protective frame. Also, if the protective frame is not allowed due to restrictions on the mounting space of the equipment used, from the above assembly process of the cell to immediately before mounting / installing into the equipment after inspection, packing, and shipping, or at an appropriate time after installation. By cutting and removing the protective frame 11, the mechanical damage to the metal lead is minimized between the manufacturing of the cell and the incorporation into the device, and the device is a smaller cell without the protective frame 11. Can be mounted on and mounted on. As shown in FIGS. 4 and 5, the protection frame portion 11 can be removed by cutting the protection frame portion 11 and the tip of the metal lead with a cutting line 14 by a punching press or cutting. The shape of the protective frame 11 can be any polygonal shape such as a rectangle, an oval, a semicircle, and a semi-oval, a circle, and other shapes.

  As shown in FIG. 5, it is necessary to provide the protective frame portion 11 at least on the side where the metal lead is pulled out of the sealing portion on the outer periphery of the exterior body. In the meantime, the metal lead can be protected. Furthermore, as shown in FIG. 4, by providing it on all four sides or three sides of the periphery of the outer package sealing part, the structure and the strength of the protective frame part can be easily obtained even in a small cell or the like. Protection is more complete. The lead of the pair of metal leads does not necessarily have to be on the same side of the sealing portion, and one lead and the other lead may be drawn from the other sealing portion side. In this case, it is preferable that the protective frame portion be installed on each of at least a pair of leads. In addition, a structure in which one of the leads is installed in a lead window provided on the back or abdomen of the cell body and only the other one is pulled out from the sealing portion is also possible and included in the present invention.

  FIG. 2 is a cross-sectional view of a flat plate electrochemical cell using the present invention. The electrode body 8 is composed of a positive electrode 1 and a negative electrode 2 that are integrally laminated in the form of a sheet on a positive electrode metal current collector 3 and a negative electrode metal current collector 4. Are layered. FIG. 2 is an example in which a laminate of an electrode, a metal current collector, and a separator is merely laminated in a flat plate shape and is not wound, particularly in the case of a thin electrochemical cell having a cell thickness of 1 mm or less. Suitable. A multi-layer electrode cell in which a plurality of such stacked bodies of a pair of electrode-metal current collector and separator are stacked as a unit and the same polarity is connected can also be obtained.

  In FIG. 2, a part of the pair of metal current collectors is extended and drawn out of the cell from the sealing portion of the exterior body, and used as a metal lead. That is, the positive electrode metal current collector 3 and the negative electrode metal current collector 4 are stacked on the metal current collector so as to serve as external lead terminals for electrically connecting the in-cell electrode and the external circuit. At the time of formation, an exposed portion where an electrode is not formed is left, and this exposed portion is formed into a predetermined lead shape by punching or cutting, and used as an external lead terminal.

  The thickness of the metal lead part is preferably the same as that of the electrode layer forming part of the metal current collector because the manufacturing process is easier, but the thickness of the electrode layer forming part and the lead forming part is changed in advance. By using a plate, the thickness of the metal current collector portion and the metal lead portion can be made different. In particular, in the case of a thin flat plate type electrochemical cell having a thickness of 1 mm or less, it is necessary to reduce the thickness of the current collector to several μm to several tens of μm. The thickness of the metal lead part is thicker than the current collector part (electrode forming part) in order to obtain sufficient mechanical strength of the metal lead part so that the metal lead part is not broken or broken, and the failure does not occur. It is effective to do. As a result, the strength of the metal lead portion can be increased without increasing the thickness of the cell body. In addition, when a lithium ion battery, an electric double layer capacitor or the like is configured as a flat electrochemical cell, an aluminum foil generally used for a current collector as a material having high corrosion resistance during charging in a nonaqueous electrolyte. This is particularly effective when a metal with low mechanical strength such as copper foil is used.

  The electrode body 8 and the electrolyte are housed in the exterior body 9, and the outer periphery of the exterior body is hermetically sealed by heat sealing, pressure bonding, adhesion with an adhesive, or the like. When the electrode body is housed, the metal lead is housed and sealed in a state where one end is drawn out across the sealing portion at the peripheral edge of the exterior body 9. Similarly, this exterior body is previously provided with a protective frame portion in which the end portion of the exterior body film is extended in the form of an outer frame on the side where the metal lead of the portion that becomes the sealing portion on the periphery of the exterior body is drawn out in advance. When sealing the peripheral portion of the exterior body, the tip of the metal lead drawn out from the sealing portion is held between the films of the protective frame portion. In this holding, it is more preferable that the metal lead is bonded and fixed to the film of the protective frame portion, so that the occurrence of defects due to deformation, bending, breakage, tearing, or the like of the metal lead is more reliably suppressed. As shown in FIG. 5, it is necessary to provide the protective frame part at least on the side where the metal lead is pulled out of the sealing part on the outer periphery of the outer package. The metal lead can be protected. Also, as shown in FIG. 4, by providing it on three sides or all four sides of the periphery of the outer package sealing part, it becomes a structure that can easily take the size and strength of the protective frame part even in small and thin cells, etc. Lead protection is more complete.

Hereinafter, embodiments will be described with reference to the drawings.
(Example 1)
In this example, an electric double layer capacitor having the basic structure shown in FIGS. 1 and 5 is configured as a flat plate electrochemical cell according to the present invention.

A strip electrode sheet having a thickness of 100 μm and a width of 50 mm was prepared by mixing and kneading polytetrafluoroethylene (PTFE) using activated carbon powder and carbon black as a conductivity-imparting agent and binder. This electrode sheet is exposed to a 28 mm side exposed portion on one side of a positive electrode metal current collector 3 and a negative electrode metal current collector 4 made of a hard aluminum foil having a thickness of 40 μm by a conductive adhesive using carbon as a conductive filler. After being adhered and laminated and integrated, a metal lead made of an aluminum plate having a thickness of 70 μm and a width of 4 mm was joined to the exposed portion by ultrasonic welding. Next, the electrode laminate was cut to have a width of 50 mm and a length of 90 mm to produce a laminate of a pair of electrodes consisting of positive electrode 1 and negative electrode 2, positive electrode metal current collector 3, and negative electrode metal current collector 4. . After winding the laminated body of the pair of electrodes and the current collector with the electrode formation surfaces facing each other with a separator interposed therebetween, using a flat core having a width of 28 mm and a thickness of 2 mm The electrode body 8 was pressed with a load of 4 kg / cm ² .

The exterior body 9 was made of an insulating laminate film having a thickness of about 110 μm, in which nylon was bonded to the outer surface of an aluminum foil and polypropylene was bonded to the inner surface, and the polypropylene layer was folded into a bag shape with the inner surface as the inner surface. A protective frame portion 11 extended from the sealing portion is formed by a punching press on the side (the metal lead take-out side) opposite to the folded side of the exterior film. The width of the protective frame portion 11 facing the sealing portion was 5 mm. Next, the electrode body 8 is accommodated so that the positive electrode metal lead 5 and the negative electrode metal lead 6 are on the side facing the folded side of the exterior film, and the metal lead is opened from the sealing portion on the opening side facing the folded side. Was pulled out and placed and housed so that its tip was within the protective frame. First, of the openings at the three peripheral edges of the outer package body, the side from which the positive electrode metal lead 5 and the negative electrode metal lead 6 were drawn and the peripheral part of the side perpendicular thereto were heat-sealed (pressurized heat fusion). At that time, simultaneously with heat sealing of the sealing part 12, the metal lead installation part of the protective frame part 11 was also heated and pressurized in the same manner and thermally fused. Next, an electrolyte solution in which 1 mol / l tetraethylammonium tetrafluoroborate is dissolved in propylene carbonate is injected from the other opening side perpendicular to the folded side of the exterior film, and the pressure is reduced to apply the electrolyte to the electrode and separator. After impregnation, the peripheral edge of the opening was heat sealed and hermetically sealed to produce 30 electrochemical cells of this example. In addition, the positive electrode metal lead 5 and the negative electrode metal lead 6 were subjected to acid modification treatment in advance in the portion corresponding to the sealing portion of the outer package during the above heat sealing before being stored in the outer package. A resin having a thickness of 100 μm and a width of 5 mm, which is polypropylene and is in contact with the exterior body film, is thermally bonded, and acid-modified polypropylene is interposed between the metal lead and the polypropylene film layer on the side surface of the exterior body in heat sealing. .
In the flat plate electrochemical cell of this example produced in this way, there is almost no deformation of the lead part in the entire process such as inspection, characteristic measurement, and transport during and after manufacture, and defects such as disconnection and breakage There was no outbreak. The average value of the cell thickness was 2.23 mm, and the average value of the capacitance was 14.2F. FIG. 3 shows an example of an electrode body of a flat plate electrochemical cell using the present invention. The attachment angle of the metal lead to the metal current collector is vertical.
(Comparative Example 1)
Similar to Example 1, except that the electrode body similar to that in Example 1 is used and the metal lead is merely pulled out from the sealing portion without providing a protective frame on the exterior body, Comparative Example 1 according to the conventional method is used. Thirty electrochemical cells were produced. The average thickness of the cell produced in this way is 2.24 mm, the capacitance is 14.2 F, and one detachment of the lead terminal from the weld with the metal current collector occurs during the manufacture of the cell. did. In addition, the metal lead part was bent or deformed in all the cells due to the pressurization of the measuring device terminal during the measurement of the capacitance and internal resistance and the pressurization during the conveyance.
(Example 2)
In this embodiment, an electric double layer capacitor having the basic structure shown in FIGS. 2 and 4 is configured. A positive electrode made of a hard aluminum foil having a thickness of 30 μm using a conductive adhesive having carbon as a conductive filler, which is obtained by rolling a kneading mixture similar to that of Example 1 to a thickness of 80 μm as the positive electrode 1 and the negative electrode 2. The metal current collector 3 and the negative electrode metal current collector 4 are bonded and laminated together with an exposed portion serving as a lead portion on one side, and the electrode laminated portion is formed with a width of 10 mm, a length of 20 mm, and an electrode by punching press. A non-lead portion was cut so as to have a length of 15 mm and a width of 6 mm to produce a laminate of a pair of electrodes consisting of a positive electrode 1 and a negative electrode 2, a positive electrode metal current collector 3, and a negative electrode metal current collector 4. The laminated body of the pair of electrodes and the current collector was formed as an electrode body 8 having a flat plate shape that was not laminated by simply laminating the separator 7 with the electrode forming surface facing each other. By extending a part of the metal current collector and using it as a metal lead portion, it is possible to connect to an external circuit without using a separate metal lead. For the exterior body 9, a laminate film similar to that of Example 1 was used, and the metal lead of the sealing portion on one side on the width 40 mm side of the two films cut into a width of 40 mm and a length of 45 mm was drawn to the portion. The protective frame part 11 extended from the sealing part as in 4 was formed by punching press. The size of the protective frame portion 11 was set such that the width of the side surface portion was 4 mm, the width of the protective frame portion facing the sealing portion was 6 mm, and the distance between the sealing portion side and the protective frame portion side was 7 mm. The metal lead portion of the metal current collector that acts as a metal lead was positioned and accommodated in the exterior body, and the lead-out side of the metal lead at the peripheral portion of the exterior body and two sides perpendicular to the metal lead were heat sealed. At that time, simultaneously with heat sealing of the sealing portion, the metal lead installation portion of the protective frame portion was also heated and pressurized in the same manner and thermally fused. Thereafter, electrolyte injection, reduced pressure-electrolyte impregnation, and heat sealing of the opening were performed in the same manner as in Example 1, and the width was 30 mm (excluding 5 mm on each side of the protective frame), the length was 20 mm (excluding the protective frame), A flat plate electrochemical cell having a thickness of about 0.5 mm was produced. In the flat plate electrochemical cell of this embodiment, a process such as welding of an external lead terminal to a metal current collector is not required, the production efficiency is high, and the external lead terminal is made of an aluminum foil having a thickness of only 30 μm. Despite the use of a metal lead from which a part of the metal current collector is pulled out, the exposed part of the metal lead is protected by being bonded and fixed to the protective frame part of the laminate film. There were no defects such as lead breakage or breakage in the course of evaluation tests such as testing and internal resistance measurement. The electrostatic capacity had an average value of 0.5 F, and the cell thickness had an average value of 0.46 mm.
The resin constituting the exterior body may be any weather-resistant resin that does not deteriorate due to humidity or temperature in the use environment and has mechanical strength. For example, polyamide resin such as nylon, polyimide, polyester, polyolefin resin, etc. Can be used. In particular, the resin disposed on the inner surface is preferably a thermoplastic resin that can be melted and softened by heating and heat-bonded to each other, and can be hermetically sealed by heat sealing with a simple process and high reliability. Polyolefin resins such as polypropylene and polyerylene and acid-modified polyolefins are suitable. In particular, when a cell using a non-aqueous electrolyte such as a lithium battery, a lithium ion battery, or an electric double layer capacitor is configured as an electrochemical cell, if external moisture (moisture) enters the cell from the exterior body, It causes significant performance degradation and decomposition of moisture and electrolytes that have entered during charging, and if the cell expands or is severe, it ruptures. As described above, polyamide resin such as nylon, polyimide, polyester, polyolefin resin, etc. A highly weather resistant resin and a moisture-impermeable metal foil such as aluminum and a thermoplastic resin that can be heat-sealed such as a polyolefin resin such as polypropylene and polyerylene and its copolymer on the inner surface are laminated and integrated. The method of bonding and sealing the sealing of the outer periphery of the outer package by heat sealing using the laminated laminate Convenient particularly preferred are possible more reliable hermetic seal. Further, in order to house the above electrode body in the exterior body and sandwich and seal the metal lead between the exterior body films by heat sealing, between the resin inside the exterior body film and the metal lead, It is particularly preferable to interpose a sealant 10 made of a resin having a high adhesiveness, such as a resin that is acid-modified polyolefin on the side in contact with the metal lead and the side in contact with the outer package film. The sealant 10 is interposed by placing an acid-modified polyolefin resin on the resin layer on the innermost surface of the exterior body film, or the metal lead is previously acid-modified polyolefin or OLE_LINK3 and at least the side in contact with the metal lead is acid-modified polyolefin. This is possible by heat sealing using a resin OLE_LINK3, which is made of polyolefin, on the side in contact with the outer package film.

  As the separator 7 used in the present invention, those usually used in electrochemical cells can be applied. That is, when configuring a non-aqueous electrolyte battery such as a lithium battery or a lithium ion battery, a polyolefin-based polymer porous film such as polypropylene or polyethylene, a mixed paper with a nonwoven fabric or glass fiber, etc. For electric double layer capacitors, such as rayon paper making, graft polymerized polyethylene, etc., non-woven fabrics made from fibers such as cellulose, polyester, polyolefin resin and glass, paper making or polyolefin porous films can be suitably used.

In general, basic electrochemical characteristics such as operating voltage and maximum theoretical capacity of an electrochemical system as a power generation element or a storage element are defined by an electrode active material and an electrolyte described later. In the case of constituting a nonaqueous electrolyte battery such as a lithium battery or a lithium ion secondary battery in the flat electrochemical cell of the present invention, lithium metal, an alloy of lithium and other metals such as aluminum and tin as the negative electrode active material Occlusion and release of lithium ions such as carbonaceous materials obtained by firing oxides, nitrides, sulfides, graphite or organic substances such as silicon, tin, tungsten, titanium, iron, and conductive polymers such as polyacene and polyacetylene In the case where an alkaline battery is formed using a possible substance, a metal such as zinc, cadmium, or a hydrogen storage alloy can be used. As the positive electrode active material, in the case of lithium batteries or lithium ion secondary battery, CF _X and _{TiS 2,} MoS _2, NbSe _3, etc. of metal _{chalcogenide, MnO 2, MoO 3, V} 2 O 5, Li X CoO ₂ , Li _X NiO ₂ , Li _X Ni _y Co _1-y O ₂ , Li _x Mn ₂ O _{4 and} other metal oxides, reaction with lithium ions such as conductive polymers such as polyaniline, polypyrrole and polyparaphenylene Alternatively, a substance capable of occluding and releasing lithium ions can be used. In the case of an alkaline battery, oxides such as silver oxide, manganese dioxide, nickel hydroxide and nickel oxyhydroxide, hydroxides and the like are used. In the case of an electric double layer capacitor, a material having a large specific surface area such as a carbon material such as activated carbon or carbon black, a metal or another oxide can be used as an electrode active material for both the positive electrode and the negative electrode. When using the above metals such as lithium and zinc as the electrode active material, the conductive agent and the binder can be obtained by using a plate or foil that is integrally formed in a predetermined shape directly on the current collector. It is unnecessary. The present invention is not limited to these examples of electrode active materials, but can be applied to chemical cells using other electrode active materials, electric double layer capacitors, and electrochemical cells composed of power generating elements or power storage elements that combine these. I can do it. The electrode body is impregnated and occluded with an ion conductive electrolyte solution after being stored in the exterior body or before being stored in advance, thereby forming an electrochemical cell element. As an electrolyte, for example, in the case of an organic electrolyte battery, γ-butyrolactone, propylene carbonate, ethylene carbonate, butylene carbonate, dimethyl carbonate, OLE_LINK2 diethyl carbonate, OLE_LINK2 ethyl methyl carbonate, methyl formate, Lithium ion dissociation properties such as LiClO ₄ , LiPF ₆ , LiBF ₄ , LiCF ₃ SO ₃ as a supporting electrolyte in an organic solvent such as 1,2-dimethoxyethane, tetrahydrofuran, dioxolane, dimethylformamide, sulfolane, and acetonitrile alone or in a mixed solvent Lithium such as non-aqueous (organic) electrolytes in which salts are dissolved, solid polymer electrolytes in which lithium salts are dissolved in polymers such as polyethylene oxide and crosslinked polyphosphazene, or inorganic solid electrolytes such as Li ₃ N and LiI ion A conductive non-aqueous electrolyte can be used. In the case of an electric double layer capacitor, (C ₂ H ₅ ) ₄ NBF ₄ , (C ₂ H ₅ ) ₄ NPF ₄ , (C ₂ H ₅ ) ₄ instead of or in addition to the above supporting electrolyte. Ammonium salts such as NClO ₄ , (C ₂ H ₅ ) ₃ CH ₃ NBF ₄ , and (CH ₃ ) ₄ NBF ₄ , phosphonium salts, and the like are used. When a solid electrolyte such as a gel electrolyte, a polymer solid electrolyte, or an inorganic solid electrolyte is used as the electrolyte, these solid electrolytes can be used alone or in combination with a separator instead of the separator.
(Comparative Example 2)
As a separate metal lead terminal, an aluminum plate having a width of 4 mm and a thickness of 70 μm is welded to the surface on which the electrode of the metal current collector is not formed. Thirty electrochemical cells of Comparative Example 2 according to a conventional method were produced as a structure for drawing out from the sealing portion at the periphery of the outer package. The cell thus produced had a thickness of 0.63 mm and an electrostatic capacity of 0.5 F, and four detachment of the lead terminal from the welded portion with the metal current collector occurred during the production of the cell. In addition, bending and deformation of the metal lead portion occurred in all cells due to pressurization of the measuring machine terminal during measurement of the capacitance and internal resistance after manufacture and pressurization during conveyance.
(Comparative Example 3)
Similar to Example 2, a similar electrode body having a metal lead obtained by extending a part of the current collector metal was used, the protective frame portion was not provided on the outer film, and the external lead terminal was connected to the outer peripheral edge sealing portion. Thirty electrochemical cells of Comparative Example 3 according to a conventional method were produced as a drawing structure. The cell thus fabricated has a thickness of 0.46 mm and an electrostatic capacity of 0.5 F, and 12 breaks occur near the sealing portion of the lead terminal during the manufacture of the cell and subsequent inspection and transportation. did. In addition, bending and deformation of the metal lead portion occurred in all cells due to pressurization of the measuring machine terminal during measurement of the capacitance and internal resistance after manufacture and pressurization during conveyance.

  As described above, in Examples 1 and 2 according to the present invention, the thickness of the cell is thin, the metal lead is not required to be welded and the production efficiency is high as compared with the comparative example by the conventional method. It can be seen that a flat electrochemical cell with less contact failure and less occurrence of bending or deformation can be obtained.

It is sectional drawing of the flat type electrochemical cell of this invention. It is sectional drawing of the flat type electrochemical cell of this invention. It is a top view which shows the electrode, electrical power collector, and metal lead which are used with the flat type electrochemical cell of this invention. It is a top view of the plate type electrochemical cell of the present invention. It is a top view of the plate type electrochemical cell of the present invention. It is sectional drawing of the conventional flat type electrochemical cell.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Positive electrode 2 Negative electrode 3 Positive electrode metal collector 4 Negative electrode metal current collector 5 Positive electrode metal lead 6 Negative electrode metal lead 7 Separator 8 Electrode body 9 Exterior body 9a Resin film 9b Metal foil 9c Thermoplastic resin film 10 Sealant 11 Protective frame Part 12 Sealing part 13 Adhesive fixing part 14 Cutting line

Claims (6)

A metal current collector, a pair of electrodes supported on the metal current collector and functioning as a positive electrode or a negative electrode, an ion conductive electrolyte, the metal current collector, the electrode, and the electrolyte are housed and sealed. A flat plate electrochemical cell comprising: an outer package to be sealed; and a metal lead for electrically connecting the electrode and an external circuit, wherein the metal lead is held by the outer package and a protective frame. . A metal current collector, a pair of electrodes supported on the metal current collector and functioning as a positive electrode or a negative electrode, an ion conductive electrolyte, the metal current collector, the electrode, and the electrolyte are housed and sealed. A flat plate electrochemical cell having an outer package to be sealed, wherein the metal current collector is held by the outer package and a protective frame, and is electrically connected to an external circuit by the metal current collector . Positioning process for positioning the metal lead so that it is sandwiched between the outer package and the protective frame, the metal current collector, the electrode carried on the metal current collector and the ion conductive electrolyte are housed inside, and the outer package is sealed The manufacturing method of the flat type electrochemical cell including the sealing process which seals, and the fixing process which fixes the said metal lead to a protection frame part. The manufacturing method of the flat type electrochemical cell of Claim 3 including the removal process which removes the said protective frame part. The outer package comprises a metal foil, a multilayer laminate film of three or more layers having a weather resistant resin layer on the outer side and a thermoplastic resin layer on the inner side, and hermetically sealing the opening of the outer package is thermoplastic by heat and pressure. 3. The flat plate electrochemical cell according to claim 1, wherein the flat plate electrochemical cell is formed by heat sealing (heat sealing) of a resin layer. The metal foil constituting the laminate film of the exterior body is an aluminum or aluminum alloy foil, the weather resistant resin disposed on the outside is polyamide or polyester, the thermoplastic resin disposed on the inside is a polyolefin resin, and the electrochemical cell 6. The flat plate electrochemical cell according to claim 5, wherein the metal current collector of the device is made of aluminum, titanium, copper, nickel, an alloy thereof, or a stainless steel foil or plate having a thickness of 5 to 100 μm.

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