JPS6011552Y2 - flat battery - Google Patents

Description

[Detailed description of the invention] The invention enables series connection of multiple unit cells without increasing the thickness of a thin flat battery, particularly one wIt or less. Moreover, the present invention provides a flat battery having storage performance equivalent to that of a flat battery composed of one unit cell.

Conventionally, the method of connecting flat batteries in series has been to connect flat batteries with a thickness of 0.
．． A bipolar electrode was prepared by forming a positive electrode mixture layer with a thickness of about 0.2R on one side of a conductive carbon film of 0.5mm, and a negative electrode active material layer with a thickness of about 0.1wrL on the other side, and then A stacked flat battery was constructed by stacking only the voltage battery with a separator in between.

However, this had the drawback of significantly detracting from its thinness, which is one of the most important characteristics of flat batteries.

Next, using a method different from the above, as shown in the cross-sectional view in FIG. Each of the metals 2 is adhered, and a positive electrode mixture layer 3 and a separator 4 are attached to this.
and an electrolytic solution to form a unit cell, the upper side of which is covered with a plastic film 1' having positive terminal holes 7 and negative terminal holes 8, and the upper and lower plastic films 1'.

A flat battery constructed by sealing 1 was also proposed.

At this time, since it is necessary to isolate each unit cell, it is necessary to insert a partition 9 between the unit cells.

When a battery system with such a structure uses an aqueous solution as the electrolyte, the material of the conductor 6 is a very big issue.Since the conductor 6 comes into contact with the electrolyte inside the battery, it is necessary to use a highly corrosion-resistant metal. There is.

However, on the other hand, since the negative electrode metal foil 5 and the conductor 6 are made of different metals, a local battery is formed between them due to the presence of an electrolytic solution, and hydrogen gas is generally generated from the negative electrode metal foil 5 side and the gas pressure This resulted in the battery expanding.

The inventors of the present invention solved the above drawback by sealing the conductors that alternately connect the positive and negative poles of multiple unit cells in series between two plastic films surrounding the outside of the battery system. It is resolved.

Examples thereof will be described below.

Figures 2 and 4 show semi-finished products of the flat battery of the present invention, and as is clear from these figures, a foil conductor 6 is thermally bonded to the edge of a plastic film 1 whose inner surface is coated with thermal adhesive. ,
Further, the positive electrode current collector metal 2 and the negative electrode metal foil 5 are connected to this conductor 6.
It is thermally bonded to the film 1 so that it is connected by.

Next, the negative electrode metal foil 5 is covered with a separator 4, and the portion of the separator 4' protruding from the width direction of the negative electrode metal foil 5 is thermally bonded to the film 1 (see FIG. 4).

On the other hand, a thinly molded positive electrode mixture 3 is placed on the positive electrode current collector metal 2, thereby completing a semi-finished sheet of a flat battery.

On the other hand, to explain the remaining semi-finished flat battery sheet with reference to FIG. 3, a plastic film 1' made of the same material as shown in FIGS. 2 and 4 has a negative electrode terminal outlet hole 8 and a positive electrode terminal outlet hole 7.
and a negative electrode metal foil 5 on one side in the same manner as described above.
, the separator 4 and the positive electrode current collector metal 2 are thermally bonded, and the positive electrode mixture 3 is placed on the positive electrode current collector 2 to complete the process.

These two semi-finished sheets are wrapped in plastic film 1,
Lay them together so that 1' is on the outside, Figure 2,
The outside of the broken line portion 10 surrounding the battery system shown in FIG. 3 is thermally bonded to each other.

Next, a specific example of the present invention will be explained.

Thin aluminum foil with a thickness of 10μ or less is made of polyester,
A plastic film 1, 1' having a laminate structure is constructed by sandwiching plastic films such as polypropylene from both sides and forming a thin layer of vinylon or acrylic thermal adhesive on one side.

The inventors here used a plastic film with a thickness of 1.00 microns.

The plastic film 1 thus constructed is cut according to the required size and shape of the flat battery.

Plastic film 1 cut as shown in Figure 2
A foil conductor 6 having a thickness of 30 μm or less is thermally bonded to the film.

The conductor 6 is not limited to any material as long as it is made of metal and has low contact resistance and conductive resistance, but in actual use it must be able to be made thin and must have ductility.

Copper, aluminum, etc. can be easily coated with copper foil or aluminum foil with a thickness of 30 μm or less by using electrolytic copper, for example.

Next, on top of this conductor 6 bonded, a positive electrode current collector 2 made of stainless steel foil with a thickness of 30 to 50 μm and a zinc foil 5 with a thickness of 30 to 50 μm, which will serve as a negative electrode, are bonded.

Thereby, the conductor 6 electrically connects the positive electrode current collector 2 and the zinc foil 5 in series at each end thereof.

Next, a positive electrode mixture 3 in which manganese dioxide is used as a positive electrode active material and acetylene black is mixed as a conductive additive is placed on the positive electrode current collector 2. A small amount of binder is actually mixed in with manganese dioxide and acetylene black to ensure adhesion.

The specific anode mixture formulation is 100 parts by weight of manganese dioxide (
5@amount% (hereinafter simply referred to as %), 3 parts of acetylene black (15%), 1 part of rubber-based aqueous emulsion
A part of saliva (5%) and 60 parts by weight (30%) of water are added and kneaded, and a stainless steel net with a mesh size of 100 is used as a core material and filled.

The positive electrode mixture layer 3 of the flat battery is completed by adjusting the thickness of the mixture to 0.3 to 0.4rIrIn.

Similarly, the other semi-finished product of the flat battery is constructed using a similar method on a plastic film 1' having positive terminal holes 7 and negative terminal holes 8 shown in FIG.

Finally, an appropriate amount of an aqueous solution containing zinc perchlorate as an electrolyte is added to the separator 4 of these two semi-finished sheets as an electrolyte, and the temperature around the two semi-finished sheets is heated to 170° to 200°C.
Hot glue.

The adhesive part is shown in Figure 2. It is located outside the broken line portion 10 shown in FIG.

With this structure, two flat batteries can be connected in series without increasing their thickness, and the conductor that connects the unit cells can be sealed between the peripheries of the two glued plastic films. Do not touch the electrolyte inside.

This eliminates the gas generation caused by local batteries caused by the presence of electrolyte between the dissimilar metals of the conductor and the anode metal, which was the case in the past, making it possible to safely and easily connect two or more flat batteries. Can be connected in series.

[Brief explanation of the drawing]

Figure 1 is a sectional view showing a conventional flat battery, Figure 2 is a top view showing one half-finished sheet of the flat battery in an embodiment of the present invention, and Figure 3 is a top view showing the other semi-finished sheet. , FIG. 4 is a perspective view of the semi-finished sheet shown in FIG. 2. 1.1'...Plastic film, 2...
...Positive electrode current collector metal, 3...Positive electrode mixture layer, 4
... separator, 5 ... negative electrode metal foil,
6...Conductor, 1o...Boundary of the adhesive part of two plastic films surrounding the battery system.

Claims (1)

[Scope of utility model registration request] A flat battery in which a plurality of unit cells are connected in series with a foil-like conductor and sealed with two plastic films,
A flat battery in which the foil-like conductor is sealed in a bonded portion of the two plastic films bonded so as to surround the outside of the battery system.