JP2006236937A - Energy storage device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an energy storage device having good outer package efficiency by suppressing the generation of a short circuit and a micro short circuit. <P>SOLUTION: The energy storage device is constituted such that a pair of electrodes 14, 15 are arranged facing each other through a separator 16, and the separator and the electrodes are sealed by gaskets 11, 12 and collectors 13a, 13b. The separator has a part pinched by one of the pair of electrodes and a gasket. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a power storage device such as an electric double layer capacitor and a proton polymer battery.

  In recent years, with the reduction in size and weight of electronic devices, there has been an increasing demand for downsizing and weight reduction of backup secondary batteries such as coin-type electric double layer capacitors and proton polymer batteries.

  The proton polymer battery is an electrochemical storage battery using a proton conducting polymer as an electrode active material. For example, as shown in the cross-sectional view of FIG. 5, such a battery has a basic structure called a basic cell 51 having a power storage function that is singly or serially stacked, and a coin case 53 via an insulating packing 52. It is obtained by mechanically caulking with the cap 54.

  The basic cell 51 is shown, for example, in the cross-sectional view of FIG. That is, in the case of a proton polymer battery, a positive electrode 31 and a negative electrode 32 containing a proton conducting polymer as an active material are arranged to face each other with a separator 33 therebetween, and the electrolyte exists in the electrode and the separator 33. ing. As the electrolytic solution, an aqueous solution containing a proton source or a non-aqueous solution is used.

  In the proton polymer battery, an aqueous solution containing a proton source has a particularly high capacity, and therefore an acidic aqueous solution is exclusively used as the electrolyte. Therefore, the inside is sealed with the current collector 34 and the gasket 35 having acid resistance. The current collector 34 is used for further sealing with an acidic aqueous solution for electrical contact between the electrode and the outside. As the current collector, butyl rubber or elastomer added with conductivity by adding carbon or the like is used. On the other hand, the gasket 35 is for preventing a short circuit between the collectors 34 facing each other through the separator 33 and the electrodes 31 and 32 and sealing with an acidic aqueous solution, and soft plastic such as butyl rubber or thermoplastic elastomer is used. Sealing adhesion is performed by vulcanization adhesion or heat fusion.

  The separator 33 is used for preventing a short circuit between opposing electrodes and for passing electrolyte ions, and is made of polypropylene, polytetrafluoroethylene, polyethylene, or the like.

  Next, the basic cell structure of the coin-type electric double layer capacitor and the coin-type proton polymer battery will be described. The gasket 35 and the current collector 34 constituting the outer periphery have a hollow cylindrical shape and a thin disc shape, respectively. Although the inside is an electrode and a separator part, the area of the separator 33 is larger than the area of the electrodes 31 and 32 in order to avoid physical contact between electrodes.

  However, in such a cell structure, the electrodes 31, 32 and the separator 33 may be misaligned at the time of manufacture, which may cause a problem of yield reduction due to a short circuit failure. In addition, in the case of a power storage element in which the electrodes 31 and 32 swell and change in volume when impregnated with an electrolyte solution, such as a proton polymer battery, the outer circumferences of the electrodes come into contact with each other due to a slight misalignment during a vibration test, and micro shorts are often generated There is also.

  Therefore, for example, as described in Patent Document 1 (Japanese Patent Laid-Open No. 4-302126), a basic cell in which a separator is sandwiched between gaskets has been proposed.

  FIG. 4 shows a cross-sectional view of the basic cell described in Patent Document 1. Such a basic cell can be obtained as follows.

  The hollow cylindrical gaskets 42 positioned above and below the separator 41 are individually punched. At this time, the inner diameters of both gaskets 42 are made smaller than the outer diameter of the separator 41. The gasket 42 thus obtained and the current collector 43 punched out in a thin disc shape are arranged concentrically and pressed to obtain an electrode insertion case. Next, after inserting the positive electrode 44 (or the negative electrode 45) into the electrode insertion case and injecting the electrolytic solution, the separator is pressure-bonded. The negative electrode 45 (or positive electrode 44) side is produced in the same manner, but the separator 41 is not crimped at this time. The thus obtained positive electrode side cell and negative electrode side cell are arranged concentrically and bonded by vulcanization or fusion, whereby a basic cell in which the separator 41 is sandwiched between gaskets 42 can be obtained.

  In such a cell structure, since the two electrodes are separated from each other by the separator 41 and the gasket 42, there is no short circuit failure, and also the micro polymer short circuit before and after the vibration test is suppressed in the proton polymer battery. I can do it.

  However, the basic cell having such a structure requires a margin for sandwiching the separator by the gasket in addition to the vulcanization or fusion margin between the gaskets (rubbers or plastic sheets). Generally, a width of 0.5 mm or more is required for a vulcanization margin, a fusion margin, and a sandwich margin. For this reason, it cannot be said that the exterior efficiency of the power storage device having the above structure is good, and there is room for further improvement in this respect.

Patent Document 2 (Japanese Patent Application Laid-Open No. 2000-216066) uses a pair of gaskets having different shapes from each other for the purpose of applying a uniform pressure to the gasket member at the time of joining so that the separator is not involved at the time of joining. Basic cells are listed. However, in this basic cell, it is necessary to reduce the electrode area on the side where both the electrodes have the same area or the larger inner diameter, and as a result, the electrode utilization rate of such a basic cell is not good. In addition, since there is no mechanism for sandwiching the separator, it cannot be said that when the electrode swells like a proton polymer battery, short circuit failure and micro short circuit during vibration test can be excellently suppressed.
JP-A-4-302126 JP 2000-216066 A

  An object of the present invention is to provide a power storage device with good exterior efficiency while suppressing the occurrence of short circuits and micro short circuits.

  In order to solve the above-mentioned problems, the present inventors diligently studied a structure that can separate electrodes with a separator and a gasket and can efficiently use the inside of the cell, and completed the present invention. .

According to the present invention,
In a power storage device having a structure in which a pair of electrodes are arranged opposite to each other with a separator, and the separator and the electrode are sealed by a gasket and a current collector,
A power storage device is provided in which the separator has a portion sandwiched between one of the pair of electrodes and the gasket.

The power storage device has, as the gasket, a first gasket and a second gasket provided inside the first gasket,
It is preferable that the separator has a portion sandwiched between the inner surface of the first gasket and the outer surface of the second gasket.

  The power storage device can be a proton polymer battery or an electric double layer capacitor.

  According to the present invention, it is possible to provide a power storage device in which occurrence of a short circuit and a micro short circuit is suppressed and the exterior efficiency is good.

  Hereinafter, a power storage device according to the present invention will be described mainly using a coin-type proton polymer battery as an example with reference to the drawings, but the present invention is not limited thereto. In the power storage device of the present invention, the configuration of the proton polymer battery can be applied to an electric double layer capacitor except that the types of electrodes are different. Further, the shape is not limited to the coin shape.

  FIG. 1 is a cross-sectional view illustrating an example of a basic cell included in a power storage device of the present invention.

The basic cell shown in FIG. 1 has two hollow cylindrical gaskets 11 and 12. Both of them have the same outer diameter, and the inner diameter of gasket 12 is smaller. The outer diameters of the disk-shaped electrodes 15 and 14 are slightly smaller than the inner diameters of the gaskets 11 and 12, respectively, and the electrodes 15 and 14 are disposed inside the gaskets 11 and 12, respectively. Corresponding to the inner diameter of the gasket, the outer diameter of the electrode 14 is smaller than the outer diameter of the electrode 15. The thickness of the gasket 11 is equal to the sum of the thickness of the electrode 15 and the thickness of the separator 16. The thickness of the gasket 12 is equal to the thickness of the electrode 14. The separator 16 has a disk shape having an outer diameter slightly smaller than the inner diameter of the gasket 11 and is disposed inside the gasket 11. The inner diameter of the gasket 12 is smaller than the outer diameter of the separator 16 and the electrode 15. In the basic cell shown in FIG. 1, when the outer diameters of the electrodes 15 and 14 are D ₁₅ and D ₁₄ and the inner diameters of the gaskets 11 and 12 are d ₁₁ and d ₁₂ , respectively, (All units are mm).

  It should be noted that the thicknesses are equal as long as the members can contact each other without gaps in the thickness direction when the basic cell is assembled, and in terms of dimensional tolerances, for example, +0 mm, −0. It can be about 1 mm.

  The lower surfaces of the gasket 11 and the electrode 15 in the figure are in the form of mating with each other, and a disk-shaped current collector 13 a having the same outer diameter as the outer diameter of the gasket 11 is disposed thereunder. The upper surfaces of the gasket 11 and the separator 16 in the figure are in the form of mating with each other. The upper surfaces of the gasket 12 and the electrode 14 in the figure are in the form of mating with each other, and a disk-shaped current collector 13b having the same outer diameter as the outer diameter of the gasket 12 is disposed thereon. The lower surfaces of the gasket 12 and the electrode 14 in the figure are also in the form of mating with each other.

  Since the separator is sandwiched between the gasket 12 and the electrode 15 by pressure when caulking with a coin case, the electrodes are separated from each other by the separator. Therefore, short circuit failure is not caused, and generation of micro short circuit before and after the vibration test can be suppressed even in the proton polymer battery.

  As a material for the gasket used in the power storage device of the present invention, a known material that can be used as a gasket for a power storage device such as a proton polymer battery or an electric double layer capacitor can be appropriately selected and used. For example, a hollow cylindrical gasket can be obtained by punching a non-conductive butyl rubber sheet or plastic sheet into a concentric ring.

  The current collector material used in the power storage device of the present invention can be appropriately selected from known materials that can be used as a current collector for power storage devices such as proton polymer batteries and electric double layer capacitors. For example, a thin disk-shaped current collector can be obtained by punching a butyl rubber sheet or elastomer sheet imparted with conductivity by adding carbon into a circle.

  As a material for the separator used in the power storage device of the present invention, a known material that can be used as a separator for a power storage device such as a proton polymer battery or an electric double layer capacitor can be appropriately selected and used. For example, a thin disc-shaped separator can be obtained by punching a sheet of polypropylene, polytetrafluoroethylene, polyethylene or the like into a circle.

  As a material of the electrode used for the power storage device of the present invention, a known material that can be used as an electrode of a power storage device such as a proton polymer battery or an electric double layer capacitor can be appropriately selected and used. For example, a thin disk electrode formed by rolling a mixture of an electrode powder, a fluoropolymer resin and a liquid lubricant into a sheet, then drying and punching can be obtained.

  In the case of a proton polymer battery, examples of the proton conductive polymer contained in the electrode include polyaniline, polythiophene, polypyrrole, polyacetylene, poly-p-phenylene, polyphenylene vinylene, polyperiphthalene, polyfuran, polyflurane, polythienylene, polypyridinediyl. , Π-conjugated polymers such as polyisothianaphthene, polyquinoxaline, polypyridine, polypyrimidine, polyindole, indole trimer, polyaminoanthraquinone, polyimidazole and derivatives thereof; hydroxyl groups such as polyanthraquinone and polybenzoquinone (quinone And a proton-conducting polymer copolymerized from two or more monomers, and the like. By doping these polymers, a redox pair is formed and conductivity is exhibited. These polymers are selectively used as a positive electrode and a negative electrode active material by appropriately adjusting the difference in oxidation-reduction potential.

  In the case of an electric double layer capacitor, a polarizable electrode containing activated carbon can be used as both the positive electrode and the negative electrode.

  As an electrolytic solution used in the power storage device of the present invention, a known material that can be used as an electrolytic solution of a power storage device such as a proton polymer battery or an electric double layer capacitor can be appropriately selected and used. In the case of a proton polymer battery, an aqueous solution or a non-aqueous solution containing a proton source can be used, and an acidic aqueous solution can be preferably used from the viewpoint of battery capacity. In the case of an electric double layer capacitor, for example, a 20 mass% sulfuric acid aqueous solution, a quaternary onium tetrafluoroborate propylene carbonate solution, or the like can be used.

  Hereinafter, an example of a method for manufacturing a power storage device having the basic cell shown in FIG. 1 will be described.

  The gasket 11 and the current collector 13a are arranged concentrically and are joined by pressure bonding or heat fusion. Similarly, the gasket 12 and the current collector 13b are joined. In this way, two types of bottomed cylindrical electrode insertion cases having different inner diameters (thicknesses may be different) can be obtained.

  An electrode 15 is inserted into an electrode insertion case obtained by joining the gasket 11 and the current collector 13a, and an electrolytic solution is injected. The electrode 14 is inserted into an electrode insertion case obtained by joining the gasket 12 and the current collector 13b, the separator 16 is concentrically stacked there, and the separator 16 and the gasket 12 are pressure-bonded. Thereafter, these electrode insertion cases are arranged concentrically, and the contact surfaces of the gasket 11 and the gasket 12 are vulcanized and bonded to obtain a basic cell.

  In addition, the structure (one member) which the gaskets 11 and 12 originally integrated may be sufficient.

  A coin-type power storage device can be obtained by using this basic cell as the basic cell 51 of FIG. 5 and laminating as appropriate and mechanically caulking with a coin case 53 and a cap 54 using an insulating packing 52. .

  Next, another example of the basic cell of the power storage device of the present invention will be described with reference to FIG. In the example shown in FIG. 1, the gasket is divided in the axial direction of the coin cell (divided by a plane parallel to the separator surface), but in the example shown in FIG. 2, the gasket is in the radial direction of the coin cell. It has a structure divided into two.

Current collectors 23a and 23b are arranged on both sides (end surfaces in the axial direction) of a hollow cylindrical gasket (first gasket) 21. Inside the gasket 21, a hollow cylindrical gasket (second gasket) 22 having the same height as the electrode 24 and having an outer diameter slightly smaller than the inner diameter of the gasket 21 is disposed. The electrode 25 has a disk shape having an outer diameter slightly smaller than the inner diameter of the gasket 21, and is disposed inside the gasket 21. The electrode 24 has a disk shape having an outer diameter slightly smaller than the inner diameter of the gasket 22, and is disposed inside the gasket 22. The separator 26 has a disk shape having an outer diameter larger than the inner diameter of the gasket 21, and the outer edge portion of the separator is sandwiched between the inner surface of the gasket 21 and the outer surface of the gasket 22. That is, the portion outside the separator portion sandwiched between the electrode and the gasket is bent along the side surface of the gasket and sandwiched between the two gaskets. The surface of the gasket that contacts the current collector is considered as the bottom surface, and the surface that intersects the bottom surface, for example, perpendicularly is considered as the side surface. When the gasket has a hollow cylindrical shape, the inner peripheral surface is the inner surface, and the outer peripheral surface is the outer surface. In the basic cell shown in FIG. 2, when the outer diameters of the electrodes 25 and 24 are D ₂₅ and D ₂₄ and the inner diameters of the gaskets 21 and 22 are d ₂₁ and d ₂₂ , respectively, (All units are mm).

  In such a structure, the separator is sandwiched between the gasket 22 and the electrode 25, and the separator is also sandwiched between the gasket 21 and the gasket 22, so that the electrodes are separated from each other by the separator. Since it has the part pinched | interposed into two gaskets, the pinching margin of the part pinched | interposed by a gasket and an electrode can be made small. And since the separator of the part pinched by two gaskets is pinched | interposed between the side surfaces of a gasket, it can avoid that the margin of the part pinched by two gaskets influences exterior efficiency.

  Hereinafter, an example of a method for manufacturing a power storage device having the basic cell shown in FIG. 2 will be described.

  The gasket 21 and the current collector 23a are arranged concentrically and joined by pressure bonding or heat fusion. Similarly, the gasket 22 and the current collector 23b are joined. In this manner, two types of bottomed cylindrical electrode insertion cases having different inner diameters and different outer diameters of the gasket portions (thicknesses may be different) can be obtained.

  An electrode 25 is inserted into an electrode insertion case obtained by concentrically arranging and joining the gasket 21 and the current collector 23a, and an electrolyte is injected. The electrode 24 is inserted into an electrode insertion case obtained by arranging and joining the gasket 22 and the current collector 23b concentrically, and the separators 26 are arranged concentrically and pressed. At this time, the separator 26 protrudes outward in the radial direction from the gasket 22 by a margin between the two gaskets.

  The gasket portion of the electrode insertion case having the gasket 22 is inserted into the gasket portion of the electrode insertion case having the gasket 21. At this time, the outer edge portion of the separator is bent and sandwiched between the side surfaces of the two gaskets.

  Thereafter, the inner surface of the gasket 21 and the outer surface of the gasket 22 can be vulcanized and bonded to obtain a basic cell.

[Example 1]
First, the manufacturing method of an electrode is demonstrated. Polyindole, which is a positive electrode active material, is mixed with 20% by mass of vapor-grown carbon (conducting amount of polyindole as 100% by mass) as a conductive auxiliary agent in a powder blender, and PTFE (polytetrafluoroethylene) is added to the resulting mixture. 60% by mass PTFE dispersion (trade name: Polyflon PTFE, manufactured by Daikin Industries, Ltd.) was added so that the particles were 10% by mass (the amount of the mixture of polyindole and vapor-grown carbon was 100% by mass) After mixing with a stirring deaerator, the mixture was dried. To the obtained mixture, 100% by mass of water (with the amount of the dried mixture as 100% by mass) was added and kneaded in a mortar. Thereafter, the kneaded product was rolled with a roll molding machine to obtain a sheet-like electrode having a thickness of 0.2 mm. The obtained sheet-like positive electrode was punched with a punching blade to obtain a thin disc-like positive electrode (diameter 4.25 mm, thickness 0.2 mm). Similarly, Ketjen Black (trade name: Ketjen Black EC600JD, manufactured by Lion Co., Ltd.) as a conductive auxiliary agent is added to polyphenylquinoxaline which is a negative electrode active material at 25% by mass (the amount of polyphenylquinoxaline is 100% by mass). In addition, a 0.2 mm negative electrode sheet was obtained. The obtained sheet-like negative electrode was punched with a punching blade to obtain a thin disc-shaped negative electrode (diameter 4.45 mm, thickness 0.2 mm).

  Next, a method for manufacturing the electrode insertion case will be described.

  Gasket 11 made of non-electroconductive rubber sheet made of butyl rubber on current collector 13a (diameter 5.5 mm, thickness 0.1 mm) made of conductive butyl rubber sheet in which carbon is dispersed in butyl rubber to give conductivity. (Inner diameter (diameter) 4.5 mm, outer diameter (diameter) 5.5 mm, thickness 0.3 mm) are arranged concentrically and pressure-bonded using the adhesiveness of rubber to obtain an electrode insertion case having gasket 11. It was. Similarly, an electrode having gasket 12 is inserted using gasket 12 (inner diameter (diameter) 4.3 mm, outer diameter (diameter) 5.5 mm, thickness 0.2 mm) and current collector 13b (same size as 13a). Got a case.

A negative electrode was inserted into an electrode insertion case having a gasket 11 and an electrolyte was injected. Next, the positive electrode 14 was inserted into the electrode insertion case having the gasket 12, the separator 16 was concentrically overlapped there, and the separator 16 and the gasket 12 were pressure bonded. After that, these electrode insertion cases are arranged concentrically, and the gaskets 11 and 12 are vulcanized and bonded at 140 ° C. for 20 seconds under a pressure of 7 kg / cm ² (0.7 MPa) to have the structure shown in FIG. A basic cell was obtained.

  The separator 16 was used by punching a porous sheet (thickness 0.05 mm) made of polytetrafluoroethylene.

  This basic cell was integrated into an exterior container composed of a stainless steel cap and a stainless steel can through a polypropylene insulating packing, and then caulked and sealed to obtain a coin type proton polymer battery.

  Table 1 shows the exterior efficiency and electrode utilization rate of the obtained proton polymer battery, the short-circuit occurrence rate during production, and the micro-short-circuit occurrence rate before and after the vibration test.

  Here, the exterior efficiency is expressed as a percentage by dividing the void volume inside the basic cell by the volume of the basic cell on the basis of the basic cell. The electrode utilization rate is expressed as a percentage by dividing the sum of the volumes of both electrodes by the void volume inside the basic cell.

  The void volume inside the basic cell is obtained by subtracting the volume of the gasket and the current collector from the volume of the basic cell (external standard).

  The vibration test was performed according to MIL-STD (Military Standard). The short-circuit confirmation was made based on whether or not the rated voltage was reached when constant current charging was performed, and the short-circuit was determined when the rated voltage was not reached. The number of confirmations is 50.

  The micro short-circuit occurrence rate was defined as the probability when 50 charging current values after the lapse of 24 hours after reaching the rated voltage and the charging current increased 5 times or more before and after the vibration test.

[Example 2]
In Example 2, the material of the current collectors 13a and 13b was changed to the conductive butyl rubber sheet of Example 1, and SEBS (styrene ethylene butylene styrene block copolymer) resin was used, and the thickness was 0.05 mm. Obtained a coin-type proton polymer battery in the same manner as in Example 1. Since SEBS resin does not have stickiness like butyl rubber, the adhesion between the current collector and the gasket and the pressure bonding between the separator and the gasket 12 were performed by heat fusion. The heat-sealing of the current collector and gasket, and the separator and gasket 12 was performed under pressure of 6 kg / cm ² (0.6 MPa), 140 ° C., 30 seconds, pressure of 9 kg / cm ² (0.9 MPa), 140 ° C., respectively. 10 seconds.

  Table 1 shows the exterior efficiency and electrode utilization rate of the obtained proton polymer battery, the short-circuit occurrence rate during production, and the micro-short-circuit occurrence rate before and after the vibration test.

Example 3
In this example, the basic cell structure shown in FIG. 2 is adopted.

The electrode was obtained in the same manner as in Example 1. However, the diameter of the positive electrode was 4.0 mm.
Gasket 21 made of non-electroconductive rubber sheet made of butyl rubber used in Example 1 on current collector 23a made of conductive butyl rubber sheet used in Example 1 (diameter 5.5 mm, thickness 0.1 mm) (Inner diameter (diameter) 4.5 mm, outer diameter (diameter) 5.5 mm, thickness 0.5 mm) are arranged concentrically, and are pressure-bonded using the adhesiveness of rubber to provide an electrode insertion case with an inner diameter of 4.5. Obtained. Similarly, an electrode insertion case having the gasket 22 using the gasket 22 (inner diameter (diameter) 4.1 mm, outer diameter (diameter) 4.4 mm, thickness 0.2 mm) and a current collector 23b similar to the above is used. Obtained.

A negative electrode 25 was inserted into an electrode insertion case having a gasket 21 and an electrolyte was injected. Next, the positive electrode 24 was inserted into the electrode insertion case having the gasket 22, and separators 26 having a diameter of 4.6 mm and a thickness of 0.05 mm obtained by punching the same porous sheet as in Example 1 were concentrically arranged and pressure-bonded. . Thereafter, the positive electrode-side electrode insertion case is inserted into the negative electrode-side electrode insertion case so that the end of the separator is bent, and the inner surface of the gasket 21 is formed at 140 ° C. for 20 seconds under a pressure of 7 kg / cm ² (0.7 MPa). A basic cell was obtained by vulcanizing and bonding the outer surface of the gasket 22.

  Using this basic cell, a coin-type proton polymer battery was obtained in the same manner as in Example 1.

  Table 1 shows the exterior efficiency and electrode utilization rate of the obtained proton polymer battery, the short-circuit occurrence rate during production, and the micro-short-circuit occurrence rate before and after the vibration test.

Example 4
Example 4 is the same as in Example 3 except that the material of the current collectors 23a and b was changed from the conductive butyl rubber sheet of Example 3 to SEBS resin and the thickness was 0.05 mm. A battery was obtained. However, the adhesion conditions for the current collector and gasket and the separator and gasket 22 were the same as in Example 2.

  Table 1 shows the exterior efficiency and electrode utilization rate of the obtained proton polymer battery, the short-circuit occurrence rate during production, and the micro-short-circuit occurrence rate before and after the vibration test.

Example 5
In Example 5, a coin-type electric double layer capacitor was obtained by the same manufacturing method except that the electrode was a polarizable electrode composed of activated carbon in Example 1, and evaluated in the same manner as in Example 1.

  A method for manufacturing a polarizable electrode will be described.

20% by mass of Ketjen Black (trade name: Ketjen Black EC600JD, manufactured by Lion Co., Ltd.) 20% by mass (100% by mass of activated carbon) as a conductive auxiliary agent is mixed with activated carbon having a specific surface area of 1500 m ² / g in a powder blender. 60 wt% PTFE dispersion (trade name: Polyflon PTFE, manufactured by Daikin Industries, Ltd.) so that the obtained mixture has 10 wt% of PTFE particles (the amount of the mixture of activated carbon and ketjen black is 100 wt%). ) Was added, mixed with a stirring deaerator, and then dried. Water was added to the obtained mixture in an amount of 50% by mass (the amount of the dried mixture was 100% by mass), and the mixture was kneaded in a mortar. Thereafter, the kneaded product was rolled with a roll molding machine to obtain a sheet-like polarizable electrode having a thickness of 0.2 mm. The obtained sheet-like polarizable electrodes were each punched with a punching blade to obtain thin disc-like polarizable electrodes (a positive electrode having a diameter of 4.25 mm and a negative electrode having a diameter of 4.45 mm). Evaluation similar to Example 1 was performed.

Example 6
In Example 6, a coin-type electric double layer capacitor was obtained by the same manufacturing method except that the electrode in Example 3 was a polarizable electrode containing activated carbon. The electrode production method was produced in the same manner as in Example 5. However, the electrode punching diameter was changed to obtain a positive electrode having a diameter of 4.0 mm and a negative electrode having a diameter of 4.45 mm.

[Comparative Example 1]
A conventional proton polymer battery shown in FIG. 3 was produced using the same material as in Example 1. The hollow cylindrical gasket 35 had an inner diameter (diameter) and an outer diameter (diameter) of 4.5 mm and 5.5 mm, respectively, and a height of 0.5 mm. The diameters of the electrodes 31 and 32 were 4.3 mm (thickness is 0.2 mm as in Example 1), and the separator 33 was 4.5 mm (thickness was 0.05 mm as in Example 1). The same current collector as in Example 1 was used.

  Table 1 shows the exterior efficiency and electrode utilization rate of the obtained proton polymer battery, the short-circuit occurrence rate during production, and the micro-short-circuit occurrence rate before and after the vibration test.

[Comparative Example 2]
A conventional proton polymer battery shown in FIG. 4 was produced using the same material as in Example 1.

  The inner diameter (diameter) and outer diameter (diameter) of the hollow cylindrical gasket 42 positioned above and below the separator 41 were 4.0 mm and 5.5 mm, respectively, and the height was 0.25 mm. The diameters of the electrodes 44 and 45 were 3.9 mm (thickness is 0.2 mm as in Example 1), and the separator 41 was 4.5 mm (thickness was 0.05 mm as in Example 1). The same current collector as in Example 1 was used.

  Table 1 shows the exterior efficiency and electrode utilization rate of the obtained proton polymer battery, the short-circuit occurrence rate during production, and the micro-short-circuit occurrence rate before and after the vibration test.

  As can be seen from Table 1, in Examples 1 to 6, the electrode utilization rate is higher than that in Comparative Example 1, and it can be seen that the short circuit occurrence rate and the micro short circuit occurrence rate before and after the vibration test are reduced. This is because the electrode part is isolated by the separator and the gasket. That is, the space where the positive electrode is inserted is isolated from the space where the negative electrode is inserted. Further, it can be seen that Comparative Example 1 requires that both electrode areas be smaller than the separator area, resulting in poor electrode utilization efficiency.

  Furthermore, it turns out that Examples 1-6 have high exterior efficiency compared with the comparative example 2, and the difference reaches to about 20%.

It is a schematic diagram which shows the cross-section of a basic cell about one form of the electrical storage apparatus of this invention. It is a schematic diagram which shows the cross-section of a basic cell about another form of the electrical storage apparatus of this invention. It is a schematic diagram which shows the cross-section of a basic cell about an example of the conventional electrical storage apparatus. It is a schematic diagram which shows the cross-section of a basic cell about the other example of the conventional electrical storage apparatus. It is a schematic diagram which shows the cross-section of a coin-type electrical storage apparatus.

Explanation of symbols

11, 12, 21, 22, 35, 42: gaskets 13a and b, 23a and b, 34, 43: current collectors 14, 24, 31, 44: positive electrodes 15, 25, 32, 45: negative electrodes 16, 26, 33, 41: Separator 51: Basic cell 52: Insulation packing 53: Coin case 54: Coin cap

Claims (3)

In a power storage device having a structure in which a pair of electrodes are arranged opposite to each other with a separator, and the separator and the electrode are sealed by a gasket and a current collector,
The power storage device, wherein the separator has a portion sandwiched between one of the pair of electrodes and the gasket. As the gasket, it has a first gasket and a second gasket provided inside the first gasket,
The power storage device according to claim 1, wherein the separator has a portion sandwiched between an inner surface of the first gasket and an outer surface of the second gasket.   The power storage device according to claim 1, which is a proton polymer battery or an electric double layer capacitor.

Images