JPH06349681A - Electrochemical device and its manufacture - Google Patents

Abstract

PURPOSE:To improve the productivity of an electrochemical device and, at the same time, to reduce the size of the device by uniting first and second functional substance layers and separator in one body as an element main body. CONSTITUTION:A separator sheet 6, functional substance sheets 7 and 8, and conductive rubber sheets 9 and 10 which are rolled by means of rolls are respecively prepared. An integrally laminated sheet 13 is obtained by passing the sheets through rolls 11 and 12 in such a state that the first and second functional substance sheets 7 and 8 are counterposed with the separator sheet 6 in between and, in addition, the rubber sheets 9 and 10 are respectively arranged outside of the sheets 7 and 8. An element main body is obtained by cutting the laminated sheet 13 to a prescribed size. Such as electrochemical device as the electrical double-layer capacitor or battery is obtained by encasing the element main body.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrochemical device such as an electric double layer capacitor or a battery and a method for manufacturing the same, and more particularly to an improvement for improving the productivity and downsizing of the electrochemical device. It is a thing.

[0002]

2. Description of the Related Art Electrochemical devices include electric double layer capacitors and batteries, which are commonly used as first and second functional substances arranged so as to face each other with a separator interposed therebetween. An element body including a layer, and first and second for accommodating the element body and electrically connected to the first and second functional material layers, respectively.
And a case including the terminals. Here, when the electrochemical device is an electric double layer capacitor, the first and second functional material layers are respectively provided by polarizable electrodes, and when the electrochemical device is a battery, the first and second functional material layers are respectively provided. Layers are provided by the positive electrode active material and the negative electrode active material, respectively.

Specifically, the element body described above is manufactured as shown in FIG. That is, first and second functional substance layers 1 and 2 obtained by cutting a sheet made of a functional substance powder, a fluoropolymer resin, and a liquid lubricant into a predetermined size are prepared. On the other hand, polypropylene (PP) or polytetrafluoroethylene (PTF)
A separator 3 made of E) or the like, having ion permeability and electronic insulation and cut into a predetermined size is prepared. Then, the functional substance layers 1 and 2 are adhered to each surface of the separator 3 with the adhesive 4 containing polyisobutylene as a main component, and the desired element body 5 is obtained.

[0004]

However, according to the electrochemical device and the manufacturing method thereof as described above, since the element body 5 obtained as shown in FIG. 6 is used,
Encounter the following problems.

(1) Since it is necessary to assemble the functional substance layers 1 and 2 and the separator 3 after cutting each to a predetermined size, the process or equipment becomes complicated.

(2) It is necessary to bond the functional substance layers 1 and 2 to the center of the separator 3, and therefore high precision is required for the work.

(3) Since the adhesive 4 which is unnecessary for the original function of the element body 5 is used, not only is it costly, but, for example, in the case of an electric double layer capacitor, there is a decrease in performance such as a decrease in capacity. Invite.

(4) As a material for the separator 3, PP
Alternatively, although PTFE or the like is used, there is a problem that PP has low heat resistance and PTFE has high cost.

(5) Two or more element bodies 5 may be used to increase the rated voltage. In that case,
One element body 5 is placed in a case made of stainless steel or the like, and two or more unit cells are stacked, or a collector electrode body made of stainless steel or the like is inserted between each of the two or more element bodies 5, and the electrolyte solution Since it is necessary to assemble the unit cells so that they are not common, the process is complicated, the cost is high, and the overall size is large.

Therefore, an object of the present invention is to provide an electrochemical device and a method for manufacturing the same which can solve the above-mentioned problems.

[0011]

According to the present invention, there is provided an element body including first and second functional substance layers arranged so as to face each other with a separator interposed therebetween, and an element body for accommodating the element body. And a case including first and second terminals electrically connected to the first and second functional material layers, respectively, and directed to an electrochemical device, comprising: In order to solve the above-mentioned technical problem, the device body is characterized in that the first and second functional material layers and the separator are integrated.

In such an electrochemical device, between the first and second functional substances and the first and second terminals,
A conductive rubber sheet may be arranged in each case. These conductive rubber sheets are preferably integrated with the element body.

In the method for manufacturing an electrochemical device according to the present invention, a separator sheet to be a separator, and first and second functional material layer sheets and first and second functional material layer sheets, respectively, are prepared. And a step of applying roll rolling in a state in which the first and second functional material layer sheets are arranged so as to face each other with the separator sheet interposed, to obtain an integrated laminate sheet, A step of obtaining an integrated element body including first and second functional substance layers arranged so as to face each other with a separator interposed therebetween by cutting the laminate sheet into a predetermined size. And a first and second terminal for accommodating the element body, the first and second terminals electrically connected to the first and second functional material layers, respectively. Includes a step of preparing a case, a step of accommodating the element body within the case.

In the above-mentioned method for manufacturing an electrochemical device, the method further comprises the step of preparing a conductive rubber sheet, and when the rolling is applied in the step of obtaining the integrated laminate sheet, the conductive rubber sheet is First
And the second functional material layer sheet may be arranged so as to be in contact with each other.

[0015]

According to the electrochemical device of the present invention, since the element body in which the first and second functional material layers and the separator are integrated is used, the adhesive is contained in the element body. Therefore, it is possible to improve performance such as reduction of internal resistance and reduce the cost required for the pressure-sensitive adhesive.

When an element body in which a conductive rubber sheet is further integrated with the first and second functional material layers is used, a reliable contact is achieved in order to realize a reliable electrical connection between the functional material layer and the terminal. You can get the status.

Further, according to the method for manufacturing an electrochemical device of the present invention, roll rolling is applied to obtain a laminate sheet in which the separator sheet and the first and second functional material layer sheets are integrated. Since the element body is obtained by cutting it, the step of attaching the separator and the first and second functional substance layers of a predetermined size to each other while aligning them with each other can be performed as in the conventional case. It becomes unnecessary. Therefore, unlike the conventional case, a complicated process and a facility for bonding the first and second functional material layers each having a predetermined size and the first and second functional material layers are not necessary, and instead,
The element body can be obtained by a simple process or equipment that does not require high accuracy.

Further, according to the manufacturing method of the present invention, when the separator and the first and second functional material layers are handled, they can be handled as an integrated element body, so that the subsequent assembling step can be performed. You can proceed efficiently. Further, even when two or more element bodies are used, the integrated element body is easy to handle, so that the assembly process of the electrochemical device including the two or more element bodies is simplified, Therefore, the cost can be reduced.

Further, according to the manufacturing method of the present invention, since the element body is integrated by roll rolling,
A highly integrated state can be obtained, and the thickness of the entire element body can be reduced. Therefore, the positional displacement between the separator and the first and second functional material layers is unlikely to occur, and the electrical short circuit due to such positional displacement can be substantially eliminated. In addition, the reduction in the thickness of the element body as described above can further contribute to the downsizing of the electrochemical device, particularly when two or more element bodies are used.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In the present invention, an integrated element body including first and second functional material layers arranged so as to face each other with a separator interposed therebetween is shown in FIG.
It is manufactured through the steps shown in.

Referring to FIG. 1, a long separator sheet 6 to be a separator, and first and second functional substance layers and first and second functional substance layer sheets 7 to be long, respectively. And 8 are prepared respectively. In addition, long conductive rubber sheets 9 and 10 are prepared.
These are arranged in the order shown in FIG.
Roll rolling according to 1 and 12 is applied, whereby an integrated long laminate sheet 13 is produced. This roll rolling may be repeatedly performed to obtain a thinner and longer laminate sheet 13. Further, the rolls 11 and 12 used in such roll rolling may be kept at room temperature, but the degree of integration of the laminate sheet 13 is further increased by heating.

When the electrochemical device to be obtained is an electric double layer capacitor, the separator sheet 6, the functional material layer sheets 7 and 8 and the conductive rubber sheets 9 and 10 which are subjected to the above-mentioned roll rolling are more concrete. Specifically,
Each is prepared as follows.

The separator sheet 6 is made of SiO ₂ , Al ₂
A powdery substance of at least one kind selected from O ₃ , ZrO ₃ , MgO, TiO _2, etc., having a particle diameter of 0.1 to 200 μm, preferably 1 to 30 μm, and a fluoropolymer resin such as PTFE. It is produced by rolling with a heated roll, containing at least one kind of substance selected from

The functional substance layer sheets 7 and 8 are made of PTFE, ethylene-tetrafluoroethylene copolymer, and 100 parts by weight of the functional substance powder consisting of at least one of activated carbon, carbon black, graphite and manganese dioxide. 0.5 to 30 parts by weight of a fluoropolymer resin such as a chlorotrifluoroethyl-ethylene copolymer, a vinylidene fluoride copolymer, a tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer, and water, alcohol, propylene glycol Liquid lubricants such as ethylene glycol, glycerin and white oil 95 to 15
It is produced by rolling a rubbery viscous mixture obtained by kneading with 0 part by weight of the mixture with a roll heated to 40 to 350 ° C, preferably 90 to 120 ° C.

The conductive rubber sheets 9 and 10 include conductive agent fine powder made of at least one of graphite, carbon black, nickel and aluminum, and polyisobutylene.
It is produced by rolling with a heated roll, containing at least one resin selected from polyethylene, PP, etc. as a main component.

A laminate sheet 13 obtained by integrating the separator sheet 6, the functional substance layer sheets 7 and 8 and the conductive rubber sheets 9 and 10 is cut into a predetermined size in order to obtain an element body. Then, after vacuum heating and drying, the electrolytic solution is impregnated.

FIG. 2 shows the element body 14 thus obtained. FIG. 2 shows an electrochemical device 15 according to one embodiment of the invention. Element body 1
Reference numeral 4 denotes first and second functional substance layers 17 and 1 arranged to face each other with a separator 16 interposed therebetween.
8 and first and second functional material layers 17 and 1
Conductive rubber sheet 19 arranged on each outward facing surface of 8
And 20.

The element body 14 integrated as described above
Are stored in the case 21. The case 21 includes first and second case halves 22 and 23 made of a metal such as stainless steel, and a sheet-like insulator having PP as a main component with respect to an inner surface of the first case half 22. Two
The electrode plate 25 is made of metal and is arranged in close contact with the electrode plate 25. The periphery of each of the first case half body 22 and the second case half body 23 is welded or the like, whereby the case 21 is provided with a sealing structure.

In such an electrochemical device 15, the first functional substance layer 17 is electrically connected to the electrode plate 25 via the conductive rubber sheet 19, and the second functional substance layer 18 is formed.
Is the second case half 23 through the conductive rubber sheet 20.
Further, it is electrically connected to the first case half body 22.
In addition, the first case half 22 is provided with an opening 26 that exposes a part of the electrode plate 25. Therefore, the electrode plate 25 and the case halves 22 and 23 function as the first and second terminals, respectively.

The electrochemical device to which the present invention is applied, particularly the structure of the case, is not limited to that shown in FIG. For example, the first case half and the second case half are sealed to each other via an insulating gasket at their peripheral edges, and the first and second case halves are respectively the first and second cases. The present invention can be applied to an electrochemical device including a case configured to configure the terminal.

The following experiment was conducted in relation to the embodiment shown in FIG. Further, as a comparative example, an electrochemical device 15a as shown in FIG. 3 was produced by using the element body obtained by the method shown in FIG. In FIG.
The elements corresponding to the elements shown in FIG. 2 are denoted by the reference numerals shown in FIG. 2 with the subscript “a” added, and the duplicate description is omitted. In this experiment, electric double layer capacitors were prepared as the electrochemical devices 15 and 15a.

In order to obtain the electrochemical device (electric double layer capacitor) 15 according to the embodiment of the present invention shown in FIG. 2, the first and second functional substance layer sheets 7 and 8 (polarizable electrodes) shown in FIG. ), Separator sheet 6 (separator)
Also, conductive rubber sheets 9 and 10 (conductive rubber sheets) were prepared with the materials and the compounding ratios (parts by weight) as shown in Table 1 below.

[0033]

[Table 1]

From these sheets, an element body 14 shown in FIG. 2 was obtained through a roll rolling process as shown in FIG. 1, and an electrochemical device 15 (electric double layer capacitor) was produced.

Electrochemical device 15 according to such an embodiment
As a result of examining the ratio of defective products after the high temperature load test (70 ° C./2.5 V / 50 hours) of the electrochemical device 15a according to the comparative example and 10% in the comparative example, it was carried out. In the example, it was 0%. The main cause of defects in the comparative example is the first and second functional material layers 17a and 1a.
It was an electrical short between 8a.

Next, as a second experimental example, in order to increase the rated voltage, an electrochemical device (electric double layer capacitor) having a structure in which two element bodies were connected in series was produced. Figure 4
Shows an electrochemical device 27 according to an embodiment of the invention,
FIG. 5 shows an electrochemical device 27a according to a comparative example. 4 and 5, elements corresponding to those shown in FIGS. 2 and 3 are designated by the same reference numerals,
A duplicate description will be omitted.

The electrochemical device 27 shown in FIG. 4 is provided with two element bodies 14, and the conductive rubber sheet 1 is arranged in order from the top.
9, the first functional material layer 17, the separator 16, the second functional material layer 18, the conductive rubber sheet 20, the first functional material layer 17, the separator 16, the second functional material layer 18 and the conductive rubber sheet 20 Stacked and integrated. On the other hand, in the electrochemical device 27a shown in FIG. 5, the collector electrode body 28 is interposed between the two element bodies 14a.

Functional substance layers 17 and 18 (polarizable electrodes) and separator 1 in the electrochemical device 27 according to the embodiment.
6 (separator) and conductive rubber sheets 19 and 20
As the (conductive rubber sheet), a material as shown in Table 2 below and a long sheet having a compounding ratio (parts by weight) are shown in FIG.
What was manufactured through the roll rolling process as shown in FIG.

[0039]

[Table 2]

The obtained electrochemical device 27 and the electrochemical device 27a as a comparative example were subjected to a high temperature load test under the same conditions as described above. On the other hand, it was 0% in the example. The main cause of the defect in the comparative example was an electrical short circuit between the functional material layers 17a and 18a, as in the experimental example described above.

Further, the electrochemical device 27 according to the embodiment is
As compared with the electrochemical device 27a according to the comparative example, the productivity is improved and the size can be reduced.

In each of the experimental examples described above, as shown in Tables 1 and 2, a separator containing PTFE was used, but the content was as small as 2 parts by weight,
Therefore, unlike the conventional case, the cost does not increase so much.

Further, although the above-mentioned experimental example was related to the electric double layer capacitor, the same effect was obtained for the battery.

[Brief description of drawings]

FIG. 1 is a schematic front view and a partially enlarged view showing a roll rolling process included in a method for manufacturing an electrochemical device according to an embodiment of the present invention.

FIG. 2 is a sectional view showing an electrochemical device 15 according to an embodiment of the present invention.

3 is a sectional view showing an electrochemical device 15a as a comparative example corresponding to the electrochemical device 15 shown in FIG.

FIG. 4 is an electrochemical device 27 according to another embodiment of the present invention.
FIG.

5 is a cross-sectional view showing an electrochemical device 27a as a comparative example corresponding to the electrochemical device 27 shown in FIG.

FIG. 6 is a cross-sectional view schematically showing a step for obtaining an element body 5 included in a conventional electrochemical device.

[Explanation of symbols]

 6 Separator Sheet 7 First Functional Material Layer Sheet 8 Second Functional Material Layer Sheet 9, 10 Long Conductive Rubber Sheet 11, 12 Roll 13 Laminate Sheet 14 Element Main Body 15, 27 Electrochemical Device 16 Separator 17 1st Functional material layer 18 Second functional material layer 19,20 Conductive rubber sheet 21 Case 22,23 Case half 24 Sheet-like insulator 25 Electrode plate 26 Opening

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Koichi Tanaka 2-26-10 Tenjin Tenjin, Nagaokakyo City, Kyoto Murata Manufacturing Co., Ltd.

Claims (4)

[Claims] 1. A first functional material layer and a second functional material layer arranged to face each other with a separator interposed therebetween.
An element body for accommodating the element body, the first body
And a case including first and second terminals electrically connected to the second functional material layer, respectively, wherein the first and second functional material layers serve as the element body. And an electrochemical device in which the separator is integrated. 2. The electricity according to claim 1, further comprising integrated conductive rubber sheets on the surfaces of the first and second functional material layers facing the first and second terminals, respectively. Chemical equipment. 3. A separator sheet to serve as a separator, and first and second functional material layer sheets to serve as first and second functional material layers, respectively, are prepared, and the separator sheet is interposed between them. First and second
By applying roll rolling in a state in which the functional substance layer sheets of are arranged so as to face each other, an integrated laminate sheet is obtained, and a separator is interposed by cutting the laminate sheet into a predetermined size. A first and a second functional material layer disposed so as to face each other to obtain an integrated element body, which is for accommodating the element body.
And a second functional material layer. First and second terminals respectively electrically connected to the case, a case is prepared, and the element body is housed in the case. Production method. 4. The method further comprising the step of preparing a conductive rubber sheet, wherein when the rolling is applied in the step of obtaining the integrated laminate sheet, the conductive rubber sheet has the first and second functional substances. The method for manufacturing an electrochemical device according to claim 3, wherein the method is arranged so as to be in contact with the layered sheet.