JPS5882462A - Detection of operation of explosion-preventing device provided in battery - Google Patents

Abstract

PURPOSE:To increase the efficiency of a gas leakage test by providing a sealing plate with a paraffin film, and affirming whether the paraffin film was broken or opened due to pressure developed during a gas leakage or not by means of a pin-hole detector. CONSTITUTION:In a battery which has a sealing plate 3 coated with a paraffin film as indicated in Fig. (A), when any gas leakage occurs during charging, the pressure of a valve space part 17 increases due to gas flowing into the part 17 from a penetrating hole 5 provided in a positive terminal provided with an explosion-preventing device, and the paraffin film breaks to form an opening 18 as indicated in Fig. (B). After the opening 18 is formed due to the expansion caused by the internal pressure of the paraffin film 10 in such a manner as mentioned above, when a high alternating voltage is applied across electrodes 11 and 12 by use of a circuit keying device 16, electric discharge develops between the electrode 12 and the sealing plate 3 through the opening 18, and a current detector 15 detects the current. As a result, the detector 15 indicates that the paraffin film 10 is opened, and displays that the gas leakage has occured.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for confirming the presence or absence of gas discharge from an explosion-proof device of a sealed storage battery such as a nickel-cadmium storage battery, a nickel-zinc storage battery, or a lead-acid storage battery.

Sealed storage batteries generate oxygen gas and hydrogen gas from the positive and negative electrodes during charging or reverse charging, but generally have a function to eliminate these gases inside the battery. However, if the charging current is large, if the gas absorption capacity is not fully demonstrated, or if reverse charging occurs, the gas pressure inside the battery will increase and there is a possibility that the battery will explode.

For this reason, sealed storage batteries are equipped with an explosion-proof device.

However, if the explosion-proof device is activated frequently when the battery is used, the electrolyte inside the battery may be discharged at the same time as the gas, causing damage to equipment outside the battery or deterioration of the characteristics of the battery itself. This adversely affects the capacity balance between the positive and negative electrodes, causing problems such as deterioration of battery life characteristics.

For this reason, for example, in the case of nickel-cadmium storage batteries, for quick charging batteries, in order to support charging by the power input method,
Measures are being taken to increase the acid and gas absorption capacity.

However, when manufacturing batteries, variations occur in their oxygen gas absorption capacity, and some batteries may have explosion-proof devices that activate during charging, resulting in a lack of reliability as a product.

Therefore, before shipping the battery, it is necessary to confirm whether the battery has sufficient oxygen gas dissipation ability to cope with the charging current.

Conventionally, this type of confirmation involves applying water, methanol, ethanol, etc. to the gas exhaust hole to detect gas leakage from the gas exhaust hole of the battery during charging, and checking whether or not there are bubbles formed in the water, methanol, ethanol, etc. due to the exhaust gas. It was confirmed by.

However, when checking for gas leaks using this method, water, methanol, ethanol, etc. have the characteristic of forming bubbles only if gas leaks continue during charging. However, there was a problem in that it was only possible to check for gas leakage after charging had stopped. In addition, in order to improve the above-mentioned drawbacks of the conventional example, by using a solution of methanol with a non-corrosive surfactant added instead of water, methanol, etc., even after charging is completed when gas leakage has stopped, A method of checking the presence or absence of a gas leak by checking the residual substance of bubbles generated in a methanol solution containing a surfactant due to a gas leak (adding methanol containing a surfactant to the exhaust port of a battery during charging 1) Then, the thing that caused the gas leak creates bubbles, and these bubbles disappear after the gas leak stops and charging ends, but the surfactant added to the methanol becomes flocculent in the wake. There are also some that remain, allowing you to check even after charging is complete to see if there was a gas leak during charging. However, these methods generally require at least 30 minutes to charge the battery, and the battery generates heat during charging, so it is necessary to add the gas leak detection solution during charging. Yes, (if the solution is added before charging, the solution will evaporate before a gas leak occurs, making it impossible to detect a gas leak). This addition complicates the battery inspection process. Furthermore, since the solution comes into contact with the battery in the energized state or the charger terminal that is in contact with the energized battery, electrolytic corrosion of the battery or the charger terminal may occur.

In addition, a method has been devised in which an elastic material is applied on the battery sealing plate and gas leakage from the battery gas exhaust hole is confirmed by checking the swelling of the elastic material due to exhaust gas pressure. In this case, gas leakage from the gas exhaust hole must be inspected by visual observation.

The present invention solves the above-mentioned drawbacks and aims to improve the efficiency of gas leak testing.

Hereinafter, the present invention will be explained in detail with reference to the drawings.

FIG. 1 is an example of a cross-sectional view of a conventional sealed storage battery.

A positive electrode 2a and a negative electrode 2 are placed inside the metal tennis 1 which also serves as a negative electrode terminal.
b is incorporated together with the separator 2C, and insulation banking is performed by the positive terminal 9 with an explosion-proof device, which has a built-in rubber valve body 8 between the cap-integrated sealing plate 3 having the exhaust hole 6 and the sealing plate 4 having the through-hole part 5. sealed through. In the case of a nickel-cadmium storage battery, a battery being charged in an overcharged state generates oxygen gas from the positive electrode 2a, and this gas is absorbed and eliminated by the negative electrode 2b.

However, when the gas generation exceeds the gas dissipation ability of the negative electrode, the pressure of the battery increases and the rubber valve body 8 is pushed up through the through hole 5 provided inside the battery of the sealing plate 4, causing the gas exhaust hole 6 to rise.
is released outside the battery system.

When gas leakage is detected by the formation of bubbles in a liquid substance, a surface material is usually added to the sealing plate 3, and the gas generated from the exhaust hole 6 is used to generate bubbles to check for gas leakage.

In the present invention, a paraffin film of 1° is formed on the sealing plate 3, and pinhole detection is performed to determine whether or not the paraffin film is damaged or opened due to the pressure at the time of gas leakage, as shown in FIG. This is something we try to confirm using equipment.

In FIG. 2, 10 is a paraffin film formed on the sealing plate 3;
14 is a high-voltage AC power source of 100 to 1000 volts, 15 is a current detection device, and 16 is a circuit open/close switch. Further, 11 is a rod-shaped electrode that contacts the upper convex portion of the positive electrode terminal 9 with an explosion-proof device, 12 is a cylindrical electrode installed to be located in the upper space of the exhaust hole 6 of the sealing plate 3, and 113 is an electrode 11.12. This is a cylindrical insulating shield plate installed in a recess to prevent electrical discharge between the two.

As shown in Figure 3A, in a battery with a paraffin film formed on the sealing plate 3, gas leaks during charging. The pressure in the valve space 17 increases due to the gas, and the third
As shown in Figure B, the paraffin membrane bursts open 18. In this manner, the paraffin film 1o is expanded by the internal pressure, and the expanded portion is torn to form the opening 18. Using the circuit opening/closing device 16 shown in FIG. When this is applied, a discharge occurs between the electrode 12 and the sealing plate 3 through the opening 18, and the current detection device 15 detects the current, indicating that the paraffin film is open, indicating that there is no gas leakage. Show what happened.

A film of a certain kind of material is formed on the sealing plate 3 in this way, and the film is opened by the pressure increase in the valve space 17 when gas leaks, and the presence or absence of gas leak is checked using a high voltage discharge leaf checker. When using this method, the following properties of the coating material are required.

(1) Good adhesion to metal.

(2) It must have the property of easily opening under the pressure of a gas leak. (3) When using a liquid that solidifies by drying, etc., it must have the property of not flowing into the gas exhaust hole 3.

(4) Not corrosive to metals.

For example, if the characteristic (2) above is low, that is, the film strength is strong, and the characteristic (1) is high, that is, the adhesive strength is strong, the internal pressure of the battery increases during charging, pushing up the rubber valve body 8. Even if the gas tries to flow out of the battery, the gas is blocked by the film and cannot flow out of the battery, leading to a risk of battery rupture. Furthermore, if the characteristic (1) is low and the adhesion between the coating and the sealing plate is weak, the coating may peel off from the sealing plate when gas leaks and the pressure in the valve space 17 increases. As a result, gas flows out of the battery, and no pores are formed in the coating.

As mentioned above, the above characteristics (1) to (
4), especially (1)? Consideration must be given to satisfying (2) at the same time.

In the present invention, after careful consideration of the above matters, it was decided to use paraffin as the coating material.

Next, a method for forming the paraffin film 1o on the sealing plate 3 will be described.

The paraffin used in the present invention has a melting point of about 700,
It is also possible to apply melted paraffin on the heated sealing plate 3 to form a paraffin film, but such a method does not satisfy the above-mentioned characteristics (■), so liquid paraffin does not flow into the gas exhaust hole. There is a problem that the paraffin flows into the valve space 17 and fills the valve space 17 with paraffin, preventing gas from being discharged.

Therefore, in the present invention, paraffin 10' processed into a ring shape as shown in FIG. We used a method of adhering them to form a paraffin film.

In the method of forming a paraffin film on a battery sealing plate by pressurizing paraffin adhesion as described above, the paraffin gas is 0 exhausted as in the case of forming a paraffin film by applying molten paraffin on the battery sealing plate. No infiltration into the holes 6 was observed, and the adhesive strength of paraffin to the battery sealing plate was at the same level as when melted paraffin was applied to the battery sealing plate, as described in the above-mentioned film characteristics (1).
was fully satisfied.

The first method for confirming the operation of the explosion-proof device according to the present invention is as follows:
As part of the assembly process for sealed batteries, a paraffin ring can be placed on the battery sealing plate to check the operation of the explosion-proof device, and a high-pressure discharge leak checker can also be used to check the operation of the explosion-proof device. This can be done automatically, making it possible to significantly streamline the process of checking the operation of explosion-proof equipment by mechanizing it.

[Brief explanation of the drawing]

Figure 1 shows an example of a nickel-cadmium storage battery;
The figure shows paraffin applied to the sealing plate of a nickel-cadmium storage battery according to the present invention, and a current detection device is brought into contact with it. Figure 4 shows the pinhole-shaped pattern caused by the operation of the explosion-proof device on the paraffin membrane. Figure 4 shows the paraffin processed into a ring shape. 3... Sealing plate, 6... Gas exhaust port, 9
...Positive terminal with explosion-proof device, 1o...Paraffin film coated on sealing plate 3, 10'...
Paraffin ring, 11.12... High pressure discharge electrode, 13... Cylindrical insulating shield plate, 14...
. . . High-pressure discharge power supply, 15 . . . Current detection device, 18 . . . Pinhole on paraffin film formed by activation of explosion-proof device. Name of agent: Patent attorney Toshio Nakao and one other person Figure 2 Figure 3 Figure 4

Claims (1)

[Claims] A cylindrical insulator is interposed between the positive and negative electrodes of the current detection device of a high-pressure discharge leaf checker, and one end of the positive or negative electrode and one end of the cylindrical insulator are covered with a paraffin film. A terminal that is in contact with one terminal and the other is not covered with a paraffin film.