JPH08162126A - Liquid leakage inspecting method for electrolytic solution in battery - Google Patents

Abstract

PURPOSE: To provide a liquid leakage inspecting method for electrolytic solution in a battery with which judgement of presence of electrolytic solution leakage can be easily and accurately conducted. CONSTITUTION: A container surface of a battery 50 wherein an electrolytic solution 56 is stored inside of a sealed container 51 is cleaned with a cleaning liquid 12. Based on a magnitude of increase of conductivity of the cleaning liquid 12 after using for the cleaning, presence of liquid leakage of the electrolytic solution in this battery is judged.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for inspecting a liquid electrolyte for leakage in a battery.

[0002]

2. Description of the Related Art In recent years, various small batteries have been used as a built-in power source for various small electronic devices such as watches, calculators, cameras, headphone stereos, and electronic toys. Figure 5
For example, the structure of a button battery 50 as an example of a small battery is shown. In this figure, 51 is a metal container in which a container body 52 also serving as a positive electrode terminal and a sealing lid 52 also serving as a negative electrode terminal are hermetically joined. , Stainless steel or nickel (or gold) plated steel. Then, in the metal container 51, a positive electrode acting substance 54, a separator 55, an electrolytic solution 56, and a negative electrode acting substance 57 are provided. 5
Reference numeral 8 is a positive electrode ring, and 59 is a gasket as a sealing ring.

By the way, in the manufacture of the button battery 50, it is necessary to completely seal the container body 52, the sealing lid 53, and the joint portion, but this is incomplete in mass-produced ones. There is something like this. Therefore,
In a post-manufacturing inspection process, a liquid leak inspection such as whether the sealing is complete is performed together with the performance inspection.

By the way, if the sealing is not complete, the electrolytic solution 56 contained in the metal container 51 exudes to the outside, and the components contained in the electrolytic solution 56 cause the container 5
1 A very small stain is formed on the surface. Therefore, conventionally, an inspector has checked the presence or absence of the stain with the naked eye or a magnifying glass to perform a liquid leak inspection.

[0005]

However, it is necessary to have a very high visual acuity and to be very careful when performing inspection with the naked eye or a magnifying glass of an inspector to find a very small stain of a trace. A skilled inspector is required. Also, when you inspect with the naked eye,
The range of their eyesight and attention is limited, and sometimes they are overlooked. In addition, the method of inspecting with the naked eye has a problem that it takes time even if the inspection is performed in a random manner.

The above problem is not limited to button batteries, but other batteries such as coin type batteries, cylindrical type batteries, prismatic type batteries,
This is also widely occurring in batteries in which an electrolytic solution is contained in a sealed container, such as plate batteries and automobile batteries.

The present invention has been made in consideration of the above matters, and provides a method for inspecting a leakage of an electrolyte solution in a battery, which makes it possible to judge whether or not the electrolyte solution has leaked out very easily and accurately. Is intended.

[0008]

In order to achieve the above object, the present application provides two inspection methods. A method for inspecting a leakage of an electrolytic solution in a battery according to a first aspect of the invention is to wash the surface of a container of a battery containing an electrolytic solution in a sealed container with a cleaning liquid and to measure the conductivity of the cleaning liquid used for cleaning. The presence or absence of electrolyte leakage in the battery is determined based on the increase.

In the method for inspecting the electrolyte leakage in the battery of the second invention, the battery containing the electrolyte in the sealed container is irradiated with X-rays, and the characteristic X-rays generated at that time are detected by a detector. The spectrum of the characteristic X-ray is obtained by determining the presence or absence of electrolyte leakage in the battery based on this spectrum.

[0010]

In the first aspect of the invention, for example, the surface of the button battery to be inspected is washed with pure water, and the conductivity of the pure water after cleaning is increased by a degree relative to the conductivity before cleaning. See what you are doing. This is because if the electrolyte leaks, the conductivity of pure water after cleaning increases, and if the increase exceeds a certain reference value (for example, 0.5 μS / cm), the button battery It is determined that electrolyte leakage has occurred.

In the second invention, for example,
When a button battery to be inspected is irradiated with X-rays, characteristic X-rays are generated from the surface of the battery. The spectrum of the characteristic X-ray can be obtained by measuring this with an X-ray detector. When a characteristic X-ray derived from an element of the same component as the component of the electrolytic solution in the battery is detected in this spectrum, the button battery determines that the electrolytic solution is leaking.

As described above, in any of the above-described inspection methods, the pass / fail judgment is digitized and rational, so that the inspection accuracy is greatly improved.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First, the first invention will be described. This invention should be called the conductivity method.

A small amount (for example, about 15 ml) of pure water is prepared as a cleaning liquid. The conductivity of this pure water is measured in advance by a liquid conductivity meter 10 operating on the measurement principle (electrode method) as shown in FIG. 1, and the numerical value at that time is stored in a memory (not shown) as a measured value before cleaning. ). In FIG. 1, 11 is a cell containing a cleaning liquid 12 as a test liquid, 13 and 14 are measuring electrodes, 15 is a stabilized voltage source, and 16 is an ammeter.

Then, the button battery 50 shown in FIG. 5 is immersed in the cleaning solution, shaken, or sprayed with the cleaning solution on the surface of the button battery 50 by using an appropriate spraying device. The surface is thoroughly washed, and the impurities adhering to it are dissolved in the washing liquid.

Next, the conductivity of the cleaning liquid after the cleaning is measured by the liquid conductivity meter 10, and the numerical value at this time is stored in a memory (not shown) as a measured value after cleaning.

Further, the measured value before cleaning is subtracted from the measured value after cleaning, and the difference is a constant reference value, for example, 0.5 μm.
It is determined whether or not S / cm is exceeded. When the magnitude of the difference exceeds the reference value, the button battery 5
It was determined that the electrolyte solution 56 leaked at 0,
It is rejected as a defective product. If the magnitude of the difference is less than or equal to a reference value, it is determined that there is no leakage,
The quality is judged together with the result of the performance inspection.

Tables 1 and 2 below show an example of data when a liquid leakage test is performed based on the above-mentioned conductivity method, and a lithium battery was used as the battery. The electrolyte solution of this battery was prepared by adding lithium perchlorate (LiCl) to a special non-aqueous solvent that is stable against lithium such as propylene carbonate and γ-butyl lactone and has the property of dissolving salts.
It consists of a solution of a lithium salt such as O ₄ ). Then, Table 1 shows that the magnitude of the difference exceeds the reference value, and it is determined that the electrolyte solution 56 has leaked,
Table 2 shows that the difference is within the reference value,
It shows that it was judged that there was no leakage of.

[0019]

[Table 1]

[0020]

[Table 2]

As described above, according to the first aspect of the present invention, the acceptance criteria are digitized and objective, so that it is possible to eliminate individual differences among inspectors, and the inspection results are highly reliable. The accuracy is greatly improved.

Although pure water is used as the cleaning liquid in the above-described first invention, the cleaning liquid is not limited to this, and may react with the components of the electrolytic solution 56 of the battery 50 or the metal container 51, or may react with this. A liquid other than pure water can be used as the cleaning liquid as long as it is not damaged. Needless to say, the amount of the cleaning liquid is changed depending on the size of the battery 50.

The conductivity measurement is not limited to the above-mentioned electrode method, and the electromagnetic induction method may be used. Furthermore, when a sheet-type conductivity meter such as that disclosed in Japanese Utility Model Publication No. 5-9652 is used, the amount of test liquid can be extremely small.

Needless to say, the reference value for the quality judgment is appropriately set according to the type of battery.

Next, the second invention will be described. The present invention should be called the characteristic X-ray method.

Before describing the second invention, the X-ray fluorescence analyzer used in the present invention will be schematically described with reference to FIG. 2. In FIG. 2, 21 is an X-ray source for generating X-rays 22, Reference numeral 23 denotes a sample mounting position, 24 denotes an X-ray detector for detecting characteristic X-rays 25 generated in the sample by irradiating the sample provided at the sample mounting position 23 with X-rays 22, and 26.
Is an AD converter, 27 is a multi-channel analyzer, 2
8 is a computer.

In the fluorescent X-ray analyzer 20, the X
The sample is irradiated with the X-rays 22 emitted from the radiation source 21, the characteristic X-rays 25 emitted from the sample are detected by the X-ray detector 24, and the output signal is passed through the AD converter 26 and the multi-channel analyzer 27 to a computer. The spectral data can be read at 28.

An inspection method using the fluorescent X-ray analyzer 20 will be described. A button battery 50 is set as a sample at the sample mounting position 23.

The surface of the button battery 50 is irradiated with X-rays 22. In this case, the entire surface of the container 51 is irradiated.

By the irradiation of the X-rays, characteristic X-rays 25 are generated from the surface of the battery 50. This is detected by the X-ray detector 24, and its output signal is input to the computer 28 via the AD converter 26 and the multi-channel analyzer 27, whereby spectral data can be obtained.

When characteristic X-rays derived from the same element as the electrolyte solution 56 of the button battery 50 are detected in the spectrum data, the electrolyte solution 56 leaks in the button battery 50. And the characteristic X
If no line is detected, it is determined that no liquid leakage has occurred.

FIGS. 3 and 4 show examples of spectra obtained when the button battery containing the electrolytic solution containing lithium perchlorate (LiClO ₄ ) was inspected by the above-mentioned characteristic X-ray method. Then, the sample chamber was kept in a vacuum, and a continuous test was conducted under two kinds of test conditions of a voltage of 15 KV, a current of 68 μA and 50 seconds, and subsequently a voltage of 50 KV, a current of 8 μA and 50 seconds.

In the spectrum of FIG. 3, characteristic X-rays derived from Cl are recognized at the positions indicated by arrows. Therefore, in the button battery 50 in this case, it is determined that the electrolyte 56 is leaking. On the other hand, in the spectrum of FIG. 4, no characteristic X-ray derived from Cl is recognized at the position indicated by the arrow. Therefore, in the button battery 50 in this case, it is determined that the electrolyte 56 has not leaked.

Tables 3 and 4 below are shown in FIG.
5 shows qualitative results made based on the spectrum shown in FIG.

[0035]

[Table 3]

[0036]

[Table 4]

According to the second invention described above, as in the first invention, the acceptance criterion is objective, so that individual differences among inspectors can be eliminated, and the inspection result is highly reliable.
The accuracy is greatly improved.

It is needless to say that the present invention is not only applicable to the button battery described above, but can be suitably applied to all batteries in which the electrolytic solution is contained in the sealed container.

[0039]

As described above, in any of the above-mentioned inventions, the presence / absence of electrolyte leakage in a battery can be determined very easily and accurately. Since the inspection standard is clear and objective, it is highly reliable and suitable as an inspection method for mass-produced batteries. Further, almost no specialized knowledge is required, and labor saving can be expected to reduce inspection costs.

[Brief description of drawings]

FIG. 1 is a diagram showing the principle of a conductivity measuring method used in the first invention.

FIG. 2 is a diagram schematically showing an example of the configuration of an X-ray fluorescence analyzer used in a second invention.

FIG. 3 is a diagram for explaining the operation of the second invention.

FIG. 4 is a diagram for explaining the operation of the second invention.

FIG. 5 is a sectional perspective view showing a configuration of a button battery as an example of a small battery.

[Explanation of symbols]

12 ... Cleaning solution, 22 ... X-ray, 25 ... Characteristic X-ray, 51 ... Container, 56 ... Electrolyte.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Masaki Yokoi 2 Higashimachi No. 2, Kichijoin Miya, Minami-ku, Kyoto-shi, Kyoto

Claims (2)

[Claims] 1. A battery in which an electrolytic solution is housed in a hermetically sealed container is washed with a washing liquid, and the washing liquid provided for washing is used to increase the conductivity of the battery. A method for inspecting a leakage of an electrolytic solution in a battery, which comprises determining whether or not there is a leakage of the electrolytic solution. 2. A battery containing an electrolytic solution in a sealed container is irradiated with X-rays, the characteristic X-rays generated at that time are detected by a detector, and a spectrum of the characteristic X-rays is obtained. The method for inspecting electrolyte leakage in a battery is characterized by determining whether or not the electrolyte has leaked in the battery.