JPS5818864A - Seald type battery - Google Patents

Abstract

PURPOSE:To surely prevent electrolyte leakage by means of a simple seal structure without reducing an effective power-generating area by applying chromium plating containing chromium oxide on at least a sealing interface of an anode metallic portion which is in contact with a sealing material. CONSTITUTION:A 0.1-2mu thick chromium plating layer 6 containing chromium oxide is formed on a contact interface between a sealing material 3 and a current collecting lead 4. This plating layer (a black chrimium plating layer) 6 is previously formed on a metallic current collecting side, and surely formed in at least a metallic portion on an anode terminal side and proferably also on a cathode terminal side along portions which are in contact with the sealing material 3. The plating layer 6 forms strong and stable connection with metallic portions, and can prevent alkaline electrolyte leakage caused by chemical and electrochemical carrosion.

Description

[Detailed description of the invention] The present invention relates to a sealed battery.

For example, sealed alkaline batteries are shown in Figure 1 or Figure 2.
As shown in the figure, a separator 2b containing an anode active material 2a and an alkaline electrolyte is placed inside a metal battery case l that also serves as a terminal.
and a power generation element 2 formed by arranging cathode active material 2C in a layered manner.
When loaded, the battery case l is sealed with a sealing material 8r, and the sealing material 8 is electrically insulating, and the anode terminal side and the cathode terminal side are insulated and isolated from each other by this sealing material 11. It has the following configuration.

The main concern with such sealed batteries is
The problem is how to stably confine the electrolytic solution contained in the power generating element 2, which is sealed inside, and prevent it from leaking to the outside.

In particular, in flat or button-shaped small sealed alkaline batteries as shown in Figures 1 and 2, seals are required to prevent leakage of alkaline electrolyte in order to achieve the goal of miniaturization. The structure has to be simple. However, as is well known, the Phulkali electrolyte used there has an extremely strong leaching power (and strong chemical and electrochemical corrosive power), and is particularly prone to creep along the metal surface on the cathode side. For this reason, in the past, a layer 8a of epoxy resin or bituminous material, for example, is disposed at the interface between the sealing material 8 and the cathode side metal portion 4 (or lbl) in contact with the sealing material 8, thereby preventing the creep of the alkaline electrolyte. However, epoxy resins and bituminous materials are not necessarily stable substances over time, and at least when they are arranged in a layer at the above interface, they can cause ↓Ruri 11-b to occur in the alkaline electrolyte over a long period of time. In addition, if the sealing material 8 is made of glass or ceramics, providing the epoxy resin or bituminous substance at the interface between the sealing material and the metal part is not recommended due to the temperature etc. of the sealing material 8. Due to trade-offs, it is impossible to overuse the sealed alkaline battery of the mesh seal type.Here, as the sealing material 8, a so-called hermetic seal using glass, ceramics, etc. Even if the alkaline electrolyte is of this type, the alkaline electrolyte still causes creep along the interface between the sealing material 8 and the gold-plated portion 4, thereby causing leakage.

Also, regarding the above-mentioned Yoshin sealed alkaline battery,
Nausea chemical reactions applied inside the battery case often produce nascent hydrogen, but this nascent hydrogen corrodes the interface between the sealing material 8 and the metal part, which causes alkaline electrolyte leakage. There are many cases where this is the cause. In addition, the hydrogen generated within the battery reduces the internal pressure of the battery, causing the above-mentioned sealing material 8
This may destroy the adhesion between the metal part and the metal part that comes into contact with it, and this may cause liquid leakage. In addition, many alkaline batteries use zinc chloride as the cathode storage 2C, but this zinc chloride allows the sealing material 8 and gold JI! The interface with the other parts becomes hydrated, and along with this icing, the above-mentioned 11-p also progresses.

In view of the above, in a relatively small sealed battery as shown in Figure 1 or Figure 2, electrolyte can leak within its extremely limited volume without impairing the effective power generation capacity. To ensure that liquids can be prevented,
This is extremely difficult.

The purpose of this invention is to prevent electrolyte leakage caused by the various factors mentioned above, even in relatively small sealed alkaline batteries as shown in Figures 1 and 2. To reliably prevent nuisance by using a simple sealing structure without impairing the effective power generation area at all.

In the sealed battery according to the present invention, chromium plating containing chromium oxide, which is generally called black chrome plating, is applied in advance to the sealing interface of at least the 4 cathode side l/I4 portions that are in contact with the sealing material. As a result, first, mechanically, a strong and stable bonding state is obtained between the chromium plating layer and the gold part, and culturally and electrochemically, a strong and stable bonding state is obtained between the chromium plating layer and the gold part. The oxide is extremely stable against alkaline electrolytes and polar materials in batteries, and has a sufficiently high hydrogen overvoltage and is sufficiently stable against nascent hydrogen. This makes it possible to reliably prevent alkaline electrolyte leakage due to the above-mentioned hammering factor. - Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 8 shows an embodiment of a sealed battery according to the present invention. The battery shown in the figure uses an alkaline aqueous solution as an electrolyte, and is of almost the same type as the conventional battery shown in Figure 1. Separator 2b containing anode active material 2 a e alkali 11 electrolyte and cathode active material 2
A metal current collector 11-dead 4 which also serves as a cathode terminal is installed in the center of the upper part of the case l.
passes through the annular gap portion 6 between the case 1 and the lead 4.
are sealed with a sealing material 8 made of glass, and both terminal sides are electrically insulated and isolated from each other. Then, on the gold H portion in contact with the glass sealant 8, that is, on the contact interface between the sealant 8 and the current collector lead 4, a chromium plating 116 containing chromium oxide is formed with a thickness of, for example, 0.1 to 2a. ing. Six chromium plating layers (black chromium plating layers) containing this chromium oxide were previously formed on the metal portion of the current collector tray. This chromium plating layer 6 containing chromium oxide is provided along the portion that contacts the sealing material 8 above.Furthermore, the chromium plating layer 6#i containing chromium oxide is provided at least on the cathode terminal side. A chromium plating layer 6 containing chromium oxide must be provided on the metal part.However, it is desirable to provide the chromium plating layer 6 containing chromium oxide on the anode terminal side as well.

Chrome plating in which chromium oxide is present is generally referred to as black chrome plating, and can be carried out, for example, under the plating conditions shown in the table below.

By performing plating under the above conditions, a chromium plating layer 6 containing about 25% or2o8 as chromium oxide is obtained. Note that the oxide contained in the plating layer 6 formed on the surface of the metal part in contact with the sealing material 8 is Or
20 a is suitable ↑, but OrO, 0rb2.0r20
5.0r08 etc. may be used.

Furthermore, the ratio of chromium oxide in the plating layer 6 is 104
The above is desirable.

FIG. 4 shows another embodiment of the invention, and the battery shown in this figure is of the same type as that shown in FIG. In the battery shown in the figure, the battery case l is divided into an anode side case part 1a and a cathode side case part 1b, and an annular sealing material 8 is interposed between the negative case part la+1b, so that the inside can be sealed. A loaded shot [! The material is sealed.

In this case, 8 pieces of sealing material, nylon, 11 propylene,
A sweet acid resin, such as polyethylene, which is electrically insulating and has elasticity is used. Both the anode side case part 1a and the cathode side case part 1b are made of gold I14,
The case portion 1a serves as an anode terminal, and the case portion 1b serves as a cathode terminal. In the case of this embodiment, the metal parts that come into pressure contact with the sealing material 8, that is, both case parts 1
A chromium plating layer (black chrome plating layer 16) containing the chromium oxide is provided near each opening end of a and tb.

This black chrome plating layer 6 must be provided at least in a portion KFi along the contact interface between the #5 pole side case portion 1b and the sealing material 8. This is common to the above-mentioned embodiments, but the reason is that the alkaline electrolyte tends to cause creep, particularly along the cathode-side metal surface, due to the potential difference within the battery. Again, that black chrome plating
It is more preferable to provide 1 g not only on the cathode side but also on the anode side. In addition, the formation of this black chrome plating layer 6 is as follows:
It can be formed in the same manner as in the case described above.

Now, as mentioned above, the black chromium plating N16 containing chromium oxide on the sealing interface of the metal part in contact with the sealing material 8
As described above, this plating layer 6 exhibits a very strong and stable bond with the metal part on which it is formed, and as a result, the plating layer 6 will progress along the surface of the metal part. Creep caused by the alkaline electrolyte is prevented. In addition, the plating layer 6 containing chromium oxide is stable against alkaline electrolytes, and is also extremely stable against nascent hydrogen that often occurs in batteries. Moreover, by exhibiting a sufficiently high hydrogen overvoltage, leakage of alkaline electrolyte caused by color and therefore chemical and electrochemical corrosive effects can be reliably prevented. Furthermore, the plating layer 6ij containing chromium oxide has the property of being extremely difficult to hydrate, and therefore, in an alkaline battery using hydrated zinc as the cathode material 2c, the zinc hydrate Even if it comes into direct contact with the edge of the interface between the sealing material and the metal part, there is a situation L3 where the alkaline electrolyte leaks.
[It will never be reached.

As described above, leakage of the alkaline electrolyte can be reliably prevented by using an extremely simplified seal structure without making the seal part too complicated.

Next, an example of specific leakage resistance test results of the sealed battery according to the present invention and the conventional sealed battery will be shown.

The test was conducted on both types: the flat sealed alkaline battery (Type B) shown in Figure 1 or Figure 8, and the nine-button sealed alkaline battery (Type B) shown in Figure 2 or Figure 4. In each case, the type of sealing material and the type of leakage-proof material provided along the interface between the sealing material and the metal part were varied. The exam is il! The samples were stored in an environment with a temperature of 60C and a humidity of 904 degrees, and the results were as shown in the table below.

As is clear from the above table, the group of sample batteries (shoulder 8~) constructed according to the present invention has better leakage resistance performance than the conventionally constructed batteries (41, 2) in both types A and B. has improved significantly. This is the sealing material 8
This is because a black chromium plating layer 6 containing chromium oxide is provided along the interface between the gold' II 4 portion in contact with this, especially the entertainment portion on the cathode side.

The case of a sealed battery using an alkaline aqueous solution as the main electrolyte has been described above, and the present invention can bring about particularly excellent effects in this type of battery. However, it is very effective in improving the leakage resistance of sealed batteries other than alkaline batteries, such as those that use light metals such as Ll for the cathode and non-aqueous electrolytes. It is.

As described above, the sealed battery according to the present invention has a relatively simple structure, and has excellent leakage resistance performance, etc. in sealed batteries, where structural simplification is unavoidable for miniaturization. to enhance

[Brief explanation of the drawing]

FIG. 1 and FIG. 2 are cross-sectional views showing examples of conventional sealed alkaline batteries, and FIGS. 8 and 4 are cross-sectional views showing examples of sealed alkaline batteries according to the present invention. l・・・・・・Gold maple battery case 2・・・・・・
...Power generation element 8... Sealing material 4... Current collector lead 6... Chrome plating N1 containing chromium oxide (black (Chromium plating layer) Patent applicant: Fuji Electrochemical Co., Ltd. Agent
Patent Attorney - Kensuke Color σ ta 2

Claims (1)

[Claims] (1) A power generating element is loaded into a metal battery case that also serves as a terminal, and the battery case is sealed with a sealing material, and the sealing material is electrically insulating, and the sealing material connects the anode terminal side and the cathode terminal side. In a sealed battery where the terminal side and the terminal side are insulated and isolated from each other, the small (
A sealed battery characterized in that the sealing area of the metal part on the 41m pole side is pre-plated with chrome containing chromium oxide.