JPH02281607A - Electrical double layer capacitor - Google Patents

Abstract

PURPOSE:To reduce a contact resistance between polarized electrodes and current collecting materials and to lessen an ESR by a method wherein graphite sheets are respectively provided between the electrodes and the current collecting materials. CONSTITUTION:Unvulcanized insulative rubber sheets are punched to form as non- conductive gaskets 5, the gaskets 5 are respectively arranged on current collecting materials 2 obtainable by punching unvulcanized conductive rubbers, are fixed by pressure and recessed parts are formed. Punched graphite sheets 3 are respectively inserted in these recessed parts and a carbon paste is filled in the sheets as polarized electrodes 4. Then, after a pair of these paste-filled sheets are arranged and combined into one through a porous separator 6 of polypropyrene make in a direction in which the electrodes 4 oppose to each other, the combined material is left to stand in an atmosphere of 125+ or -<5> deg.C under a pressure of 4kg/cm<2> and these sheets are closely adhered. Then, after 8 sheets of these basic cells 1a are laminated in series and are formed as a laminated material 7, the laminated material 7 is housed in a metal sheathed case 9, an insulating case 8 with electrode plates 10 arranged on the laminated material 7 is made to cover on the laminated material 7, a mechanical pressure is applied to the laminated material 7 through the plates 10 and the case 8 and the upper end of the case 9 is sealed by caulking.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an electric double layer capacitor, and more particularly to a structure in which the electric double layer content is in the vicinity of a current collector of an element.

[Conventional technology]

Conventionally, this type of electric double layer capacitor has a pair of polarizable electrodes 4 made of powdered activated carbon, an electrolyte solution, etc. sandwiched between an electrically insulating and ion permeable porous upper pallet 6, as shown in FIG. , a current collector 2 made of conductive rubber or the like disposed on the outside thereof, and a non-conductive material such as insulating rubber that hermetically seals the porous separator 6 and polarizable electrode 4 from the sides between the pair of current collectors. It was configured by arranging a gasket 5. Moreover, the above-mentioned configuration is applied to the electric double layer capacitor element 1b.
(hereinafter referred to as a basic cell), and by stacking the required number of cells, it is possible to produce a component that can withstand the desired operating voltage.

That is, as shown in FIG. 5, a laminated body 7 in which the necessary number of basic cells 1b are laminated according to the working voltage is connected to a metal exterior case 9, and the aforementioned metal exterior case 9 is insulated to prevent a short circuit between the laminated body 7 and the metal exterior case 9. It has a structure in which it is cased with a case 8 and the electrode 11 is pulled out through the electrode plate 10.

Electric double layer capacitors have two layers between activated carbon particles and between basic cells.
In order to reduce the contact resistance between the polarizable electrode and the current collector, a pressure of 9/cd is applied from above and below to the laminate 7 of the basic cell 1b, and while this is maintained, the metal exterior case 9 is opened. The edges are bent inward and caulked to ensure stable properties.

[Problem to be solved by the invention]

The above-mentioned conventional electric double layer capacitor has a large contact resistance between the polarizable electrode and the current collector, and therefore the electric double layer capacitor has a large equal series resistance (hereinafter referred to as ESR). Therefore, when discharging with a large current after charging, there is a drawback that a necessary voltage drop is caused due to the ESR of the electric double layer capacitor.

An object of the present invention is to provide an electric double layer capacitor in which the contact resistance between a polarizable electrode and a current collector can be reduced, and as a result, the ESR of the electric double layer capacitor can be reduced.

[Means to solve the problem]

The electric double layer capacitor of the present invention includes a separator made of an electrically insulating and ion permeable material, a pair of polarizable electrodes placed opposite to each other with the separator in between, and a pair of polarizable electrodes placed on the outside of each polarizable electrode. In an electric double layer capacitor, the electric double layer capacitor has a polarizable current collector and an insulating gasket that airtightly accommodates each polarizable electrode through the current collector. The feature is that a sheet is inserted.

〔Example〕

Next, the present invention will be explained with reference to the drawings.

FIG. 1 is a cross-sectional view of a basic cell according to an embodiment of the present invention, and FIG. 2 is a cross-sectional view of an electric double layer capacitor according to an embodiment of the present invention.

First, as shown in FIG. 1, a graphite sheet 3 having a diameter of 6.0 mm is punched out from a graphite sheet having a thickness of 100 μm. Next, an unvulcanized insulating rubber sheet with a thickness of 0.6IIJE was placed concentrically with an inner diameter of 5mm. Q u.

The non-conductive gasket 5 is punched out with an outer diameter of ILOfl, and the above-mentioned non-conductive gasket 5 is placed concentrically on the current collector 2 made by punching out unvulcanized conductive rubber with a diameter of ILO11 ml, and is crimped to form a recess. form. A paste-filled sheet is obtained by inserting the graphite sheet 3 into this recess and filling it with a carbon paste containing a mixture of 30% by weight sulfuric acid and powdered activated carbon as a polarizable electrode 4. Next, apply a pair of these paste-filled sheets to the polarizable electrodes 4.
In the opposite direction, the thickness of the polypropylene group is 25 μm.

After combining the two concentrically arranged through a porous separator 6 with a diameter of 8, a pressure of 9/cd was applied vertically to the parts 4, and this pressure was maintained in an atmosphere at a temperature of 125 °C for 3 hours. This was left to stand, and the unvulcanized non-conductive gaskets and the unvulcanized non-conductive gasket and the current collector were brought into close contact to obtain a basic cell la of the present invention.

Next, as shown in FIG. 2, eight basic cells 1a of the present invention are stacked in series to form a laminate 7, which is then housed in a metal exterior case 9, and an insulator with an electrode plate 10 arranged on the laminate 7. Cover the case 8 and place the electrode plate 10. 3 to the laminate 7 through the insulating case 8
A mechanical pressure of 0 JCg/cj was applied and this state was maintained for t, and the upper end of the metal exterior case 9 was caulked and sealed to obtain an electric double layer capacitor with an operating voltage of 5 .

FIG. 3 shows the average ESR value of 50 electric double layer capacitors of the basic cell of the present invention in which an electric double layer capacitor of the conventional basic cell 1b and a graphite sheet are inserted. The horizontal axis is the level, and the vertical axis is the E of the electric double layer capacitor.
It is SR. The ESR of an electric double layer capacitor with a graphite sheet inserted was reduced by 40% compared to the conventional one, making it possible to realize an electric double layer capacitor with a lower ESR than the conventional one.

Further, as shown in Table 1, the electric double layer capacitor of the present invention has almost the same characteristics as the conventional capacitor except for the KESR.

〔Effect of the invention〕

As explained above, by inserting a graphite sheet between the polarizable electrode and the current collector, the present invention can reduce the contact resistance between the polarizable electrode and the current collector, thereby lowering the EAR of the electric double layer capacitor. There is an effect that can be achieved.

[Brief explanation of drawings]

FIG. 1 is a longitudinal cross-sectional view of an electric double layer capacitor element according to an embodiment of the present invention, FIG. 2 is a longitudinal cross-sectional view of an electric double layer capacitor consisting of a basic cell according to an embodiment of the present invention, and FIG. This is a graph showing the relationship between the ESR of the electric double layer capacitor obtained in the present invention and the conventional electric double layer capacitor, and is a graph in which the average value of 50 samples is plotted. FIG. 5 is a vertical cross-sectional view of an example of an electric double layer capacitor made up of a conventional basic cell. 1a・°・Basic cell of the present invention, 1b... Conventional basic cell, 2... Current collector, 3... Graphite sheet, 4
... Polarizable electrode, 5... Non-conductive gasket, 6.
... Porous separator, 7... Laminate, 8... Insulating case, 9... Metal exterior case, 10... Electrode plate,
11... Electrode. Agent Patent Attorney Susumu Uchihara ES Shaku (n,) Figure Z2 Two book names are also A and mainland sushi 2; Current collector NZ country is; Juhani body ui/ Figure 4/l Figure 5

Claims (1)

[Claims] a separator made of an electrically insulating and ion-permeable material; a pair of polarizable electrodes disposed opposite to each other with the separator in between; a current collector disposed outside of each polarizable electrode; An electric double layer capacitor having an insulating gasket that airtightly accommodates each polarizable electrode via an electric body, the electric double layer capacitor having a graphite sheet between the polarizable electrode and the current collector. double layer capacitor.