JPH01222428A - Electric double layer capacitor - Google Patents

Abstract

PURPOSE:To enable the title capacitor to be miniaturized and manufactured at low cost by bringing collectors into contact with the ends only of a capacitor element. CONSTITUTION:Within a capacitor provided with a capacitor element 1 comprising polarizing electrodes 2, 3 and a separator 4, collectors 6 are brought into contact with the ends of the capacitor element 1. That is, the capacitor element 1 is laminated and wound around so that the polarizing electrodes 2 and 3 may mutually protrude the respective ends on the opposite sides through the intermediary of the separator 4. The collectors 6 coming into contact with the ends only of the capacitor element 1 cover small area to be miniaturized at low cost. Furthermore, the surface of collectors 6 can be made rugged to be brought into contact with the ends of the capacitor element 1 so that the contact resistance may be lowered.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to an electric double layer capacitor.

(Prior art) Conventionally, electric double layer capacitors include wound types and laminated types. For example, a round carbon sheet is used as a polarizable electrode, and an expanded metal such as aluminum metal or etched foil is used to collect current. The 1i electric body is in contact with the sheet surface of the polarizable electrode, and the tab is connected to the 1i electric body to connect it to the terminal.

(Problems to be Solved by the Invention) However, the above configuration has the disadvantage that the current collector requires approximately the same area as the polarizable electrode, which hinders miniaturization and increases the cost.

An object of the present invention is to improve the above-mentioned drawbacks and provide an electric double layer capacitor that is easy to downsize and inexpensive.

(Means for Solving the Problems) In order to achieve the above object, the present invention provides an electric double layer capacitor having a capacitor element consisting of a polarizable electrode and a separator, in which an FC electric body is provided on the end face of the capacitor element. The present invention provides an electric double layer capacitor characterized by contact.

(Function) According to the present invention, the current collector contacts only the end face of the capacitor element, has a small area, and can be made compact and inexpensive.

Note that contact resistance can be reduced by making the surface of the current collector uneven and contacting the end face of the capacitor element. Further, if the width 11 of the concave portion and the width 12 of the convex portion satisfy 12≦11≦1.5 layers, the contact resistance can be more effectively reduced.

Contact resistance can be similarly reduced when carbon paint is applied to the surface of the current collector.

The current collector may also serve as a case or may be provided separately, and similar effects can be obtained.

Hereinafter, the present invention will be explained based on examples.

In FIG. 1, 1 is a capacitor element, as shown in FIG. 2, in which polarizable electrodes 2 and 3 are stacked and wound with a separator 4 in between so that their ends protrude to opposite sides. be. 5 is a case in which this capacitor element 1 is housed. Reference numeral 6 denotes a current collector disposed on the bottom surface of the case 5, and the surface is uneven in a striped, hole-shaped, or mesh-like pattern. is pressed and in contact with. 9 is a lid that seals the case 5. Reference numeral 10 denotes a current collector that passes through this base 9 and contacts the other end surface of the capacitor element 1, and its contact surface is uneven.

Next, when the ESR was measured for the case where the uneven portions 7 and 11 of the current collectors 6 and 10 were striped, the results shown in the table were obtained.

The manufacturing conditions are as follows.

Polarizable electrode: Particle size 15-71μ (DBP method), oil absorption ω480mj2
/1009 conductive carbon black mixed with 10 wt% tetrafluoroethylene, applied for 10 minutes using a drying machine, pressed to form a sheet with a thickness of 400 μm, and punched out into a disc shape with a diameter of 10 cm. Separator: 100μm thick polypropylene non-woven fabric, electrolyzed
Solution: 1 mole of LiCl0s dissolved in a propylene carbonate solution. The surface of the current collector Ni-aluminum metal was formed into stripes as shown in Figure 3 to form uneven parts, and the width of the recessed part 11+ and the width of the raised part 12 were arbitrarily set. Both cases are cylindrical and made of aluminum, with and without carbon paint applied.

As is clear from the margin table below, Examples 1 and 2 that satisfy the relationship 12≦11≦1.5M are approximately 69% or less when carbon paint is used, compared to other Examples 3 to 7. In the case without, it is about 67% or less. Furthermore, the ESR is smaller when carbon paint is applied than when it is not applied.

FIG. 4 shows a developed view of a capacitor element 12 used in another embodiment of the present invention. In order to improve the withstand voltage, one polarizable electrode 13 and 14 is separated into two parts, which are separated from each other from opposite sides. Their ends 15 and 16 are made to protrude, and the other polarizable electrode 17 is made narrower than the separator 18 .

- (Effects of the Invention) As described above, according to the present invention, since the current collector is in contact with only the end face of the capacitor element, a double-layer capacitor that can be miniaturized and manufactured at low cost can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a front sectional view of an embodiment of the present invention, FIG. 2 is an exploded sectional view of a capacitor element used in the embodiment of FIG. 1,
FIG. 3 is a cross-sectional view of a current collector placed on the bottom surface of the base of the embodiment of FIG. 1, and FIG. 4 is a developed cross-sectional view of a capacitor element used in another embodiment of the present invention. 1.12... Capacitor element, 2.3, 13.14... Polarizable electrode, 4.18...
Separator, 5... Case, 6.10... Current collector, 7... Uneven part. Patent applicant Hitachi Capacitor Co., Ltd.

Claims (4)

[Claims] (1) An electric double layer capacitor having a capacitor element consisting of a polarizable electrode and a separator, characterized in that a current collector is brought into contact with the end face of the capacitor element. (2) The electric double layer capacitor according to claim 1, wherein the surface of the current collector that contacts the end surface of the capacitor element is uneven. (3) The width l_1 of the concave part of the current collector and the width l_2 of the convex part are l_
The electric double layer capacitor according to claim 2, wherein 2≦l_1≦1.5 mm. (4) The electric double layer capacitor according to any one of claims 1 to 3, wherein the current collector has a surface coated with carbon paint.