JPH0367461A - Manufacture of electrode for laminated battery - Google Patents

Abstract

PURPOSE:To strengthen the engagement between a carbon plastic plate and an insulating frame by insert injection-molding the insulating frame on the carbon plastic plate while insert injection molding dies are heated in a specific temperature range. CONSTITUTION:Injection molding dies 31 and 32 insert injection-molding a carbon plastic plate 27 and an insulating frame 28 are constituted controllably at a constant temperature. The temperature of dies 31 and 32 at the time of injection molding is kept at 70-90 deg.C. The frame 28 is insert injection-molded around the plastic plate 27 in the constant-temperature state of dies 31 and 32. In an intermediate electrode 23 formed by such a means, the melting property between the peripheral section of the plastic plate 27 and the insulating frame 28 is improved, an electrolyte is prevented from being leaked from a biting portion, and the binding strength at this portion is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION A. Field of Industrial Application This invention relates to a method for manufacturing electrodes for use in batteries with a laminated structure by insert injection molding.

B0 Summary of the Invention The present invention is a method for manufacturing a battery electrode having a laminated structure, by injection molding an insulating frame on a carbon plastic plate with an insert injection mold at a temperature of about 70°C to about 90°C. The electrode is manufactured to ensure that the part is watertight.

C1 Conventional technology Recently, the development of battery power storage systems has been promoted.
As a part of this, electrolyte circulation type metal halogen stacked secondary batteries as illustrated in FIGS. 2 to 6 have been developed.

This mainly consists of a battery body, a tank, and a piping system, and as shown in the structural principle diagram in Figure 2, the battery body 1 is separated by a separator 2 made of an ion exchange membrane or a porous membrane.
The anode chamber 3 and the cathode chamber 4 are divided into an anode chamber 3 and a cathode chamber 4, and there are wave transmitting tubes 5, 6 and a liquid return tube 7 for circulating the electrolyte in the two electrode chambers, respectively.
Electrolyte tank connected by 8 9. 1O was provided, and an electrolytic solution of zinc bromide (Z n B r 2) was circulated to each electrode chamber. In addition, 11 is an anode, 12 is a cathode, 13 and 14 are both liquid feeding pumps, and 15 is a valve.

During charging, the electrolytic solution circulates in the direction of the arrow in the figure, and the reaction of Zn"+2e--Zn occurs at the cathode 12 and 2Br--+Br"+2e at the anode 11, and the bromine produced at the anode 11 is It becomes a molecule, mixes in the electrolyte, partially dissolves, and mostly becomes a complex with the complexing agent in the anolyte, and is precipitated and accumulated in the electrolyte tank IO on the anode chamber side. Also, during discharge, each electrode 1 is connected with the electrolyte circulating.
1 and 12, a reaction opposite to the above reaction formula occurs, and the precipitates (Zn, Br,) are consumed (oxidized, reduced) on each electrode 11.12, and electrical energy is released. be.

Further, in the zinc-bromine battery having the above-mentioned construction principle, a stack of a large number of cell laminated structures is used as an element of a laminated battery as illustrated in FIG. This bolts the entire stack from both ends.

For example, there is a
Constructed by stacking 0 cells. That is, a separator plate 21 is placed next to the current collection mesh 19 of the end plate electrode 18 made of carbon plastic connected to one external electrical system via a gasket 20, a spacer mesh 22 for maintaining a predetermined distance is placed, and the carbon plastic The flat plate intermediate electrodes 23 are stacked, and the packing 20 is stacked, and so on.
Finally, the carbon plastic end plate electrode 18 connected to the other external electrical system is overlapped to form a bipolar connection, so that a total of 30 cells are laminated.

A positive electrode manifold 24 and a negative electrode manifold 25, which are liquid flow holes, are provided at the four corners of the stack thus laminated.

Furthermore, each separator plate 21 is constructed by integrally molding a frame plate 21a around the separator 2 made of a microporous membrane, and microchannels 26 are installed in a symmetrical shape on both sides of the upper and lower sides of the separator plate 21. Become. The microchannels 26 shown by solid lines on the negative side of the microchannels 26 uniformly spread the electrolytic solution introduced from the positive electrode manifold 24 on the diagonal line and flow it over the entire surface of the separator 2, or collect the solution therefrom. In addition, the microchannel 2 shown by the broken line on the other side
6 is for introducing and recovering the electrolytic solution from the negative electrode manifold 25.

In this way, between the electrodes arranged on both side surfaces of each separator plate 21, cells that become the unit battery illustrated in FIG. 2 are constructed, and 30 of these cells are connected in series to form a stack. It is configured so that

The intermediate electrode 23 of the stack as described above was constructed by injection molding a plastic insulating frame 28 around a conductive carbon plastic plate 27, as illustrated in FIG.

In manufacturing this intermediate electrode 23, first, a carbon plastic plate 27 is formed by cutting a carbon plastic flat plate material into the dimensions and shape of the electrode, and this is placed in an injection mold as an insert, and the molten plastic material is injected. death,
As illustrated in FIG. 5, the carbon plastic plate 27
As shown in FIG. 4, they are integrally formed so that they are joined at a so-called hooked portion that extends into the insulating frame 28 with a uniform width all around the circumference.

D0 Problems to be Solved by the Invention In the conventional intermediate electrode 23 as described above, the welding of the part (so-called biting part) where the peripheral edge of the carbon plastic plate 27 is molded so as to be enclosed by the insulating frame 28 is not successful. , this biting part tends to create a gap.

When a battery is constructed using such an intermediate electrode with a gap in the biting part, the anode electrolyte and the cathode electrolyte, which are separated by the intermediate electrode 23, are separated from each other by the surface side of the intermediate electrode 23 or the catholyte electrolyte. There was a problem in that a liquid junction was formed in which the liquids flowed into the back side and mixed, resulting in a decrease in battery performance.

In view of the above-mentioned points, it is an object of the present invention to provide a new method for manufacturing an electrode for a laminated battery, in which the peripheral side of a carbon plastic plate and an insulating frame are reliably welded together.

81 Means for Solving the Problems The method for manufacturing an electrode for a laminated battery of the present invention is to heat an injection mold for insert injection molding an insulating frame into a carbon plastic plate to about 70°C to about 90°C. The insert injection molding process is performed in this state.

10 Effects By using the method described above, when the plastic material for the insulating frame is injected into the injection mold, it reaches the carbon plastic plate before it is cooled down by the mold, and the carbon plastic plate is heated. It has the effect of sufficiently melting the biting part to ensure a strong weld.

G. Example Hereinafter, an example of the method for manufacturing an electrode for a laminated battery according to the present invention will be described with reference to FIG.

In FIG. 1, parts corresponding to the conventional example shown in FIGS. 2 to 6 are denoted by the same reference numerals, and detailed explanation thereof will be omitted.

In the main part longitudinal sectional view of FIG. 1, 27 is a carbon plastic plate, 28 is an insulating frame, and 31 and 32 are a pair of insert injection molds.

The carbon plastic plate 27 and the insulating frame 28 are made of the same resin material. In this example, the carbon plastic plate 27 is made of thermoplastic resin mixed with materials such as crabbon black and graphite, and the insulating frame 2
8 is made of the same thermoplastic resin as the carbon plastic plate 27.

In addition, an injection mold 31.3 for insert injection molding an insulating frame 28 into such a carbon plastic plate 27 is provided.
2 is configured to be capable of constant temperature control.

In this example, the temperature of the molds 31 and 32 during injection molding is maintained at 70°C to 90°C.

While the mold is kept at a constant temperature, an insulating frame 28 is inserted and injection molded around the carbon plastic plate 27, as shown in FIG.

The intermediate electrode 23 formed by such a method improves the weldability between the peripheral side of the carbon plastic plate 27 and the insulating frame 28, prevents the electrolyte from leaking from this biting part, and prevents this. This can improve the bonding strength of the parts.

Next, in order to confirm the effect of the means of this example, the mold temperature was variously changed and the bond strength of the biting portion was measured. The test results are shown below.

(The following is a blank space) From the above table, it is understood that when the mold temperature is set to 70'C or higher, the bond between the carbon plastic plate 27 and the insulating frame 28 can be further strengthened.

Furthermore, it is understood that setting the mold temperature to 100'C is inappropriate because the carbon plastic plate 27 is deformed and cannot be used as a product.

Therefore, it can be seen that sufficient results can be obtained at a mold temperature of about 70°C to about 90'C. Preferably, the mold temperature is set at 80° C. to 85° C. By doing so, stable quality can be obtained.

Effects of the H9 Invention As detailed above, according to the method for manufacturing an electrode for a laminated battery of the present invention, an injection mold for insert injection molding an insulating frame into a carbon plastic plate is heated for about 70 minutes. Since the insert injection molding process was performed at a temperature of ℃ to approximately 90℃, when the plastic material for the insulating frame was injected into the injection mold, the plastic material was cooled before it was cooled down by the mold. It reaches the carbon plastic plate and sufficiently melts the biting part of the carbon plastic plate to securely and firmly weld it, which has the effect of ensuring the watertightness of the biting part and improving the bonding strength.

Furthermore, by improving the reliability of the watertightness of the interlocking part between the carbon plastic plate of the electrode and the insulating frame, when this electrode is used in a battery, the catholyte and anolyte electrolyte that are separated by this electrode are This has the effect of preventing alternating current through the biting part, stably maintaining the performance of the battery over a long period of time, and improving its reliability.

[Brief explanation of drawings]

Fig. 1 is a vertical cross-sectional view showing the main part of the insert injection molding state for explaining one embodiment of the method for manufacturing electrodes for a laminated battery according to the present invention, and Fig. 2 is a schematic explanation showing the principle of a conventional battery. Figure 3 is an exploded perspective view of the stack part that is an element of the battery, Figure 4 is a front view of the intermediate electrode, Figure 5 is a vertical cross-sectional view, and Figure 6 is an enlarged vertical cross-section of the main parts. It is a front view. 23... Intermediate electrode, 27... Carbon plastic plate, 28... Insulating frame, 31.32... Injection mold. Figure 3: Disassembled perspective view of essential parts 0 7a 3 2] 8 6 Front view of electrode Figure 1: Longitudinal sectional view of essential parts Schematic explanatory diagram Figure 5: Longitudinal sectional view of electrode Enlarged sectional view of essential parts

Claims (1)

[Claims] (1) A method for producing an electrode for a laminated battery, characterized in that an insulating frame is insert-injected molded onto a carbon plastic plate while an insert injection molding mold is heated to about 70°C to about 90°C.