JPS5853026Y2 - flat battery - Google Patents

Description

[Detailed description of the invention] The present invention relates to a flat battery in which a power generation element is sealed by a battery case that also serves as an anode terminal, a sealing plate that seals the opening of the battery case, and a sealing packing, and an anode washer that fixes the anode to the battery case. The purpose is to improve battery assembly and make it easier to assemble batteries.

This type of flat battery includes an alkaline battery that uses monovalent or divalent silver oxide, manganese dioxide, nickel oxide, copper oxide, etc. as an anode active material and zinc as a cathode active material, carbon fluoride, manganese dioxide, There are organic electrolyte batteries that use silver chromate as an anode active material and lithium or other light metal as a cathode active material.

These batteries have been made thinner in response to the trend toward thinner digital display watches and electronic desktop calculators that use LCD 9 light-emitting diodes, etc., and recently the total battery height has been reduced to 3 mm.
The following are requested:

Under these circumstances, it is necessary to make battery parts thinner and to improve battery construction methods.

In the conventional construction method, one power generation element, such as an anode, is pressure-welded to a conductive member, such as a battery case, and then a separator, a sealing backing, the other power generation element,
For example, in the method of assembling a sealing plate containing a cathode, the total height is 3 m, considering the processing technology of the parts.
It is extremely difficult to realize a battery with a diameter of less than m.

For example, when a construction method is adopted in which a simply processed pellet-like mixture is placed in the center of the battery case, the peripheral edge of the mixture has low mechanical strength due to its compacted density, resulting in chipping, peeling, and other problems during battery construction. This causes problems such as cracks in the battery performance, and it is also difficult to place the mixture pellets in the center of the case.

In addition, in this type of thin battery, a microporous resin film with a thickness of several tens to hundreds of micrometers is normally used as the separator material, but because its strength is not sufficient, the density of the peripheral part of the mixture Even if the battery can be molded in a uniform state, the separator will dig into the periphery of the mixture, and as a result, the separator will tear or crack at that part, causing a short circuit inside the battery and preventing it from functioning as a battery. There is an inconvenience that it disappears.

In order to solve the above problem, a pellet-like mixture fixed with a conductive member with a V-shaped cross section was inserted into the battery case, and this was pressurized with a mold to push the mixture to the bottom of the case. A method of crimping and fixing was tried.

However, in order to reduce the total height of the battery, it is necessary to reduce the thickness of the conductive member to about 50μ or less, and when such a thin conductive member is used, the adhesion strength with the case, In other words, when the conductive member is crimped into the case, the fixing strength to the inner bottom of the case due to the expansion of the outer diameter is extremely weak, there is no locking effect, and the battery separates from the case during the battery construction process, making it difficult to mass-produce. There were drawbacks.

The present invention eliminates the above-mentioned conventional drawbacks and provides a flat battery suitable for mass production.

That is, the present invention is a flat battery case characterized in that a protruding piece having a conductive washer on the periphery that covers the periphery of an electrode placed at the bottom of the battery case is crimped to the inner wall of the battery case and fixed to the case. It's a battery.

The present invention will be described below with reference to a silver oxide-zinc oxide battery as an example thereof.

In the figure, 1 is a sealing plate, such as a cladding plate of a stainless steel plate and a copper plate, or a nickel plate and a copper plate.
The part in contact with the cathode is made of a composite material containing copper, tin, etc., which has a potential close to that of zinc, which is the cathode active material.

2 is a cathode made of amalgamated zinc powder; 3 is a separator made of a microporous resin film or ceramic filter having a thickness of several tens to hundreds of microns; and 4 is a battery case made of stainless steel or a nickel-plated iron plate.

Reference numeral 5 denotes an anode mixture made of a mixture of silver oxide and a conductive additive such as phosphorous graphite, and 6 an anode washer with a substantially V-shaped cross section that covers the periphery of the mixture. is fixed at the bottom of the

Reference numeral 7 denotes a sealing backing attached to the periphery of the sealing plate 1, which is made of a polymeric insulating material such as polyamide or polyethylene, and serves to insulate between the two electrodes and prevent the internal electrolyte from leaking to the outside.

Next, a method for fixing the mixture 5 to the case 1 with the washer 6 will be explained.

First, pellets of mixture 5 are placed in the center of the bottom of the case, then washer 6 is placed on top of the pellets, and the pellets are pressed and bonded using a mold.

The outer diameter of the ring-shaped portion of the washer 6 is equal to or slightly smaller than the inner diameter of the case, and has a plurality of protruding pieces 8 on the periphery, and the protruding pieces 8 are pressed by the above-mentioned pressure. It is bent along the inner wall of the case, and is fixed to the case by the resilience of the bent portion.

The anode washer 6 is made of a nickel plate, a stainless steel plate, etc., and its thickness is suitably 10 to 50 μm.

If it is 50μ or more, it is difficult to keep the total height of the battery within the specified range, and if it is 10μ or less, the mechanical strength becomes weak, making it difficult to handle.

Also, it is better to make the protruding piece 8 thinner than the thick ring-shaped part.
The press-fitting operation into the case becomes smooth.

Alternatively, the mixture 5 may be molded integrally with the washer 6 in advance and then press-fitted into the case.

As described above, according to the present invention, the mixture 5 is fixed to the case by the washer 6 provided with the protruding piece 8 that is crimped onto the inner wall of the case, so that it will not come off from the case during the subsequent battery assembly process. This makes it easier to assemble the battery.

In order to more completely fix the washer 6 to the case, the protruding piece 8 may be welded by electric welding, so-called spot welding.

Since the welded portion in this case is not located in the power generating element storage portion, it is possible to prevent local battery formation due to exposure of dissimilar metals and metal oxide film formation during spot welding.

Next, battery A of the present invention having the above configuration and battery B assembled by simply putting the mixture in the center of the case without using the washer 6.
Table 1 shows a comparison of the voltage failure rates when 500 pieces of each were stored at a temperature of 45°C.

Note that a voltage failure is one in which the open circuit voltage is 1.50V or less.

Table 2 shows the results of comparing the capacitance utilization rates when five normal voltage crystals were taken out from a product stored at a constant temperature of 45° C. and discharged at Q to a load resistor of 15.

Electric capacity utilization rate is (actual capacity) ÷ (filling capacity)
Shown as 10.0.

As described above, according to the present invention, a flat battery with a high utilization rate and stable quality can be easily obtained.

[Brief explanation of the drawing]

Fig. 1 is a partially cutaway side view of a silver oxide battery showing an embodiment of the present invention, Fig. 2 is a plan view of its washer, Fig. 3 is a longitudinal sectional view of the same, and Fig. 4 is a view of the battery before sealing. FIG. 4...Case, 5...Mixture, 6...
...Washer 8...Protruding piece.

Claims (2)

[Scope of utility model registration request] (1) A flat type in which the power generation element is sealed by a battery case that also serves as an anode terminal, a sealing plate that seals the opening of the case, and a sealing backing that is interposed between the periphery of the case and the sealing plate. 1. A flat battery, characterized in that a protruding piece having a V-shaped anode washer on its periphery that covers the periphery of an anode is crimped onto an inner wall of a battery case and fixed to the case. (2) The flat battery according to claim 1, wherein the thickness of the anode washer is 10 to 50 μm, and the thickness of the protruding piece is smaller than that.