JPH0355767A - Manufacture of solid secondary battery - Google Patents

Abstract

PURPOSE:To obtain contact between an electrolyte layer and an electrode layer sufficiently by integrating the electrolyte layer and the electrodes in predetermined disposition under pressure, and pressurizing them again after charging. CONSTITUTION:Electrode layers consisting of electrode material and binding agent as main materials are disposed on both surfaces of an electrolyte layer of solid electrolyte consisting of electrolyte and binding agent as main materials at the center, and they are integrated with each other under pressure. They are pressurized again after charging to obtain a sufficient contact between the electrolyte layer and the electrode layer, thereby a solid secondary battery with which performance deterioration is reduced can be formed.

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to a method for manufacturing so-called solid-state secondary batteries whose structural materials are all solid. So-called solid-state batteries, which are solid-state batteries, have attracted attention as both primary and secondary batteries have attracted attention because they do not leak, are expected to be highly reliable, and can be made smaller and lighter.Currently, they are mainly used for memory backup in various devices. is considered.

In this solid-state battery, a solid electrolyte is important for moving ions within the battery.
Ag" ion conductive solid electrolyte, H ion conductive solid electrolyte and R bCu4I+.sc l3.6, Cu
Cu'' ion-conductive solid electrolytes such as I-Cu20 Mo03 have been taken up.

In addition, as materials for the positive electrode, CuTiK, AgTi nails, and Chevrel phase compounds such as CuvMosss-z and FevMoeSs-z are mentioned.On the other hand, for the negative electrode, Cu, Ag, Lil. Although sWO3 and other Sheprell phase compounds similar to those for positive electrodes have been tried, copper Sheprell phase compounds with excellent reversibility were chosen for positive and negative electrodes, especially Cu2Mo●S●
A solid secondary battery using a composition of 1 i. During discharge, the positive electrode Cu changes from "0" to "1" and the negative electrode Cu changes from "4".
There is a flat part of approximately 0.45V when the positive electrode Cu changes from "1" to "2" and the negative electrode Cu changes from "3" to "3".
” to “2”. Two flat portions of about 0.2 5 V are shown.

Problems to be Solved by the Invention As materials for the positive and negative electrodes, for example, a copper Sieprel phase compound with excellent reversibility is selected, and in particular Cu2Mo
Use the combination of s S@ for both poles (1, solid electric square and "'CR b C u a l +.sC l 3.s
When charging and discharging a solid secondary battery using an Rb-based ion conductive solid electrolyte such as Rb-based ion conductive solid electrolyte, especially at a voltage of around 0.45V, some batteries show a decrease in capacity after a relatively small number of cycles. After repeated charging and discharging, the internal resistance of some batteries increases and performance deteriorates.
4 The inventors have conducted various studies on this type of battery and found the following phenomenon: t= Cu 2M o s 3
● is used as a bipolar material, and an electrode layer mainly containing this electrode material and a binder is placed on both sides, and an electrolyte layer mainly containing an electrolyte and a binder is arranged in the center.Charging is performed after the three are integrated under pressure. When fully charged, the Cu of the positive electrode Cu2MoaS● theoretically becomes ``0'' and the negative electrode becomes ``4''. In other words, MO●S
● and Cu4MoeSe.

Therefore, at the positive electrode, Cu changes from ``2'' to ``0'' and its volume decreases, while at the negative electrode, it changes from ``2'' to ``4'' and its volume increases, but this happens at the same time.

The voltage curves towards the positive electrode at
u changes from "0" to rlJ, and the negative electrode returns from "4" to "3". In either case, a large volume change occurs.a Therefore, the electrode layer, which mainly consists of the electrode material and binder, the electrolyte, and the binder. Even if the main electrolyte layer is integrated under pressure, in the conventional case, such a large volume change reduces the adhesion between the three layers, resulting in batteries with performance deterioration. Based on the analysis, the purpose is to provide a method for manufacturing a solid electrolyte battery that allows sufficient contact between the electrolyte layer and the electrode layer. After leaving Cu2Mo6S@ as a solid electrolyte, R b Cu a I +.sC l 3.
In a solid secondary battery using an Rb-based ion conductive solid electrolyte such as No. After pressurizing and integrating the two, perform a charge that can be called merging to make the Cu of the positive electrode CuaMo●S● less than ``2'' and the negative electrode Cu more than ``2''. After pressurizing again, the positive electrode Cu is completely charged. may be set to "0" and that of the negative electrode to "4", but partial charging is better, and when using about 0.45V, set the Cu of the negative electrode to about 3.5. @
It is preferable to pressurize again after increasing the pressure to a certain level.When L1 or r=0.25V is used, the Cu of the positive electrode becomes Cu+. 6 Arashi Negative electrode is Cut. Charge the battery until it reaches about s.

In either case, repressurization after partial charging is required.A sealing plate made of a thin metal plate and a resin film is placed on each pole so that the resin films are in contact with each other. You can also use pressurization.
．． Xo This method can also be directly applied to stacked batteries.

Electrode layers containing working electrode materials and a binder are placed on both sides, and an electrolyte layer containing an electrolyte and a binder is arranged in the center, and after they are integrated under pressure, charging is performed to cause a change in volume. Signs of confirmation: When pressurized again, the change in volume of the electrode material due to charging and discharging is small, so the decrease in adhesion can be greatly suppressed. Therefore, excellent discharge performance and self-discharge properties can be obtained, and the capacity can be increased with a relatively small number of cycles. No more decline.

EXAMPLE Copper siebrel (CugMoaS●) was used as the material for the positive electrode, and R bC u4I+. was used as the electrolyte. sc
Using 1L6 as a binder at 20 Wt%, commercially available polyethylene was added to a hot benzene solution with a concentration of 6Wt%, stirred thoroughly, and prepared with a width of 2000 mm using the well-known doctor blade method. A positive electrode sheet with a thickness of 350 μm was prepared.4-X
*Mo@S●) and the same electrolyte Rbc+ as the positive electrode.
．． zI+. 20Wt% of scl3.5 and binder (6W
A similar negative electrode sheet was prepared using RbCu4I+.t%) as the electrolyte. k using sC l3.5
Again, polyethylene was added as a binder to make it 13 wt%, and an electrolyte sheet with a thickness of 100AJm was made.Next, the positive electrolyte and the negative electrode sheet were added in that order. Next, conductive carbon paper shaped with a commercially available binder was placed on both sides of the battery element thus obtained, and a Cu plate with a thickness of 20 μm was placed on the outside of the conductive carbon paper, and a 130t
, integrated under pressure of 400Kg/cm"1,
After cutting this into 15 x 30 mm, I charged it at 1 mA. In about 5 hours, the positive electrode Cu went from "2" to "l" and the negative electrode showed a voltage of about 0.4 V, which corresponds to "2" to "4". After that, it was charged for 2 hours for a total of 7 hours to create a 0.2mm thick film made of polyethylene and aluminum.
Apply a laminated sheet to both sides of the battery element with the polyethylene on the inside, and press a roller press heated to 140°C to the battery element at a pressure of 300 kg/cm around the battery.
This operation repressurizes the battery element, and the polyethylene is welded around the battery and the sealing is complete. This battery was taken out to the outside.This battery was designated as A.Next, for comparison, a battery that was not subjected to the charging operation of this example before being sealed was added as B.
Using 20 cells of each battery, first compare the initial discharge voltage and capacity during normal charging and discharging.
．． When charging to 57 V and discharging to 0.3 V at 2.5 mA, the flat voltage of S A is 0.48 mA.
．． otv, discharge capacity is 4.5±0.2mAh, flat voltage of B is 0.47±0.01V, discharge capacity is 4.
There was no big difference at 5±0.2mAh.Therefore, we next investigated the life characteristics of each battery under these charging and discharging conditions.
The ambient temperature was set to 45°C, and the result was that at 200 cycles, A's discharge capacity was almost the same as the initial one, while B's discharge capacity was 4.1±0.04 mAh, and at 600 cycles, A's discharge capacity was 4.3 ±0.03mAh, 3.8± for B
0.06 mAh, and the variation in B further expanded. Effects of the Invention The solid secondary battery of the present invention (1) The volume change during charging and discharging is small. Decrease in the adhesion between the electrode layer and the electrolyte layer can be suppressed, and the discharge performance is improved. It is possible to reduce the variation in the temperature and achieve a longer life.

Claims (4)

[Claims] (1) After placing an electrolyte layer mainly consisting of an electrolyte and a binder in the center and electrode layers mainly consisting of an electrode material and a binder arranged on both sides of the electrolyte layer and integrating the three under pressure, charging is performed. , a method for producing a solid-state secondary battery characterized by repressurization. (2) Cu_2Mo_6S as material for positive and negative electrodes
Select a copper Chevrel phase compound such as RbCu_4I_1_. as a solid electrolyte. _5Cl_3_. In a solid secondary battery using an Rb-based ion conductive solid electrolyte such as _5, an electrolyte layer mainly containing the electrolyte and a binder is in the center, and electrode layers mainly containing the above electrode material and a binder on both sides thereof. After charging after the three parts are integrated and pressurized,
A method for manufacturing a solid-state secondary battery characterized by repressurization. (3) By charging, the Cu of the positive electrode becomes Cu_■_. The negative electrode Cu is Cu_3_. 3. The method for manufacturing a solid-state secondary battery according to claim 2, wherein the pressure is applied again after the pressure is reduced to about _5. (4) After integrating the electrode layer and the electrolyte layer under pressure, charging is performed, and then a sealing plate made of a thin metal plate and a resin film is arranged so that the resin films are in contact with each other, and the resin films are welded while heating. 2. The method for manufacturing a solid-state secondary battery according to claim 1, wherein a battery is formed by: