JPH0317965A - Manufacture of solid-electrolyte sheet and solid-electrolyte secondary battery - Google Patents

Abstract

PURPOSE:To strengthen the surface bonding of an electrode material layer and a solid electrolyte layer by having fluorine contained resin powder added to and dry-mixed with solid electrolyte powder and wet-kneaded, then roll- formed in a same direction and dried. CONSTITUTION:Polytetrafluoroethylene powder, e.g. is added to preset solid electrolyte material to dry-mixed both of them by a mixer and fully kneaded with isoparaffin solution added thereto, then rolled in a same direction with roller rolling technique providing reduced roller intervals, formed in a preset thickness and dried to obtain a solid-electrolyte sheet 3. It is desirable to give to least five times rolling, otherwise fiber can not fully mesh therewith to form a fragile sheet. It is thus possible to strengthen the surface bonding of an electrode material layer and a solid electrolyte layer.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a solid electrolyte secondary battery, which is entirely in a solid state.

Batteries using conventional technology solid electrolytes (all solid electrolytes) Unlike conventional batteries made of liquid electrolytes, there is no need to worry about leakage, and they can also be made smaller, lighter, and thinner. Although there are great expectations for its practical application as a power source in the microelectronics field, up to now solid electrolytes have been limited to LiI% LiI-At203.
, Li” conductive solid electrolyte such as LisN, or R
Ag” conductive solid electrolyte such as bAg4I6, RbCu
4 I+. ysC 1s. 2sS Cu I
Although Cu conductive solid electrolytes such as CuaO and MOOa have been discussed, Li, AgS, TiS2, NbSa, and Mos-, which can inter-interlate and deinterlate Cu, are also used as electrode materials. Interlayer compounds such as S* are used for the negative electrode material (upper Li, A
G, Cu, and MoeSs, which is the same as the positive electrode material, are used.

Conventional sheets of these solid electrolytes and electrodes are made of the above-mentioned electrode material, polyethylene as a binder, and solid electrolyte material.
Even though it is done by adding polypropylene, polytetrafluoroethylene resin, etc., it is especially difficult to roll the powder because it is easily stretched by applying pressure and binds the particles well. Although the structure of the solid electrolyte battery was used when forming sheets using a hollow mold, the invention was made by stacking these sheets and simply applying pressure from above and below to integrate them. The charge/discharge capacity of solid electrolyte secondary batteries constructed in Or, it causes expansion of the solid electrolyte material, resulting in its formation.Contact symptoms at the electrode material particle interface.In particular, the interfacial bond between the electrode material layer and the solid electrolyte layer, which have significantly different material powder particle sizes, is significantly deteriorated. It is something.

In this way, the conventional technology has the problem of deteriorating various battery characteristics as shown above. The purpose of this invention is to provide a method for manufacturing a solid electrolyte sheet, a method for manufacturing an electrode sheet, and a method for manufacturing a solid electrolyte secondary battery using these sheets. In order to solve the above problems, the solid electrolyte secondary battery of the present invention consists of a solid electrolyte sheet obtained by adding fluororesin powder to solid electrolyte powder, dry-mixing it, wet-kneading it, rolling it in the same direction, and drying it. , a fluororesin powder is added to an electrode material powder consisting of a mixture of an electrode active material and a solid electrolyte, dry-mixed, and then wet-kneaded.The electrode sheets obtained by rolling or molding in the same direction and drying are rolled in the same direction. It is characterized in that it is obtained by rolling in the same direction as the above-mentioned rolling direction to obtain the same solid electrolyte powder.Fluororesin powder is added to the electrode material powder, dry-mixed, and then wet-kneaded. By rolling and molding several times in the rolling direction, the fluororesin is stretched and oriented in the rolling direction within the material powder, and solid electrolyte and electrode sheets in which the fibers are intertwined can be obtained, but these sheets are rolled in the same direction. By rolling with heavy resistance in the same direction as the aforementioned rolling direction, a battery having a very strong interfacial bond in which the fibers on the surface of the electrode sheet and the fibers on the surface of the solid electrolyte sheet are intertwined in the orientation direction can be obtained.

As a result, the initial charge/discharge capacity increases, and the charge/discharge capacity does not decrease even after a relatively small number of cycles. Example 1 Figure 1 ζ Top shows a solid electrolyte secondary battery obtained in an example of the present invention. Add polytetrafluoroethylene powder at a ratio of 5 wt% to the mixture, dry mix the two with a mixer, add isoparaffin solution and knead thoroughly, and roll this in the same direction using a roller rolling method while decreasing the roller spacing by 0.02 mm ( Solid electrolyte sheet 3 was obtained by molding to a thickness of 0.50 mm and drying.
If the number of rolling is less than 5 times, the fibers will not be entangled sufficiently and a brittle sheet will be produced, so it is desirable to roll at least more than 5 times.
RbCuiI1.MoaSs) as a solid electrolyte.
? 6C 1 s. z6 at 40wt%. By adding polytetrafluoroethylene powder at a ratio of 5 wt%, using the same method as above, a thickness of 0.50 mm was obtained.As polytetrafluoroethylene, secondary particles of about 500 microns are made up of a large number of fine particles. It is preferable to roll the positive electrode sheet 1, the solid electrolyte sheet 3, and the negative electrode sheet 2 in this order so that the rolling direction is the same as the rolling direction. Using a roller press machine heated to 150°C, the rollers are rolled several times until the total thickness is 0.65mm while reducing the roller spacing by 0.02mm.1.This is cut into 15x15mm squares, and then both sides A conductive adhesive sheet with fine gold powder dispersed therein was used as the current collector 4, and then a copper foil was placed on top of it, and heated to 150°C.
The batteries were made by applying pressure and adhesion at 500 kg/cm'' using a flat plate press machine heated to 500 kg/cm, and then sealing the periphery with epoxy resin as the sealing material 5 to make a battery.This battery is called A and is compared next. For electrode sheets, without paying attention to the rolling direction
Battery B was constructed in which a solid electrolyte sheet was fabricated and integrated.Other than that, it was constructed under the same conditions as Battery A.The charge and discharge cycle characteristics were compared using the two batteries A and B. Charging and discharging conditions (charging and discharging rate 0.5 mA, end-of-charge voltage 0.55 V, end-of-discharge voltage 0.3 V, t4) The results are shown in Figure 2.

The initial discharge capacity of battery A was 1.38 mAh, while that of battery EH was 1.30 mAh;
In the case of battery A, 1000 k was better in terms of cycle characteristics.
The discharge capacity at the 1000th cycle decreased by 60% compared to the initial discharge capacity in the case of battery B, whereas the discharge capacity at the 1000th cycle decreased by only 80% of the initial discharge capacity. The solid electrolyte secondary battery obtained by the present invention (the bond between the electrode sheet and the solid electrolyte sheet becomes stronger, and the charge/discharge capacity, cycle characteristics, etc. are improved, and

[Brief explanation of drawings]

Fig. 1 shows the structure or cross section of a solid electrolyte secondary battery manufactured in an embodiment of the present invention, and Fig. 2 shows the charge/discharge cycle characteristics of the same solid electrolyte secondary battery.・Mechanical electrode sheet, 2...Negative electrode sheet, 3...Solid electrolyte sheet.

Claims (3)

[Claims] (1) A method for producing a solid electrolyte sheet, which comprises adding and dry-mixing a fluororesin powder to a solid electrolyte powder, further wet-kneading, and then rolling-molding in the same direction and drying. (2) An electrode sheet characterized in that it is obtained by adding and dry-mixing a fluororesin powder to an electrode material powder consisting of a mixture of an electrode active material and a solid electrolyte, further wet-kneading, and then rolling-forming in the same direction and drying. Manufacturing method. (3) The solid electrolyte sheet according to claim 1 is arranged between the electrode sheets according to claim 2 so that the rolling direction is the same, and the solid electrolyte sheet according to claim 1 is rolled in the same direction as the rolling direction. A method for manufacturing a solid electrolyte secondary battery.