JPH07335272A - Life detecting method for sealed lead acid battery - Google Patents

Abstract

PURPOSE:To detect the life of a lead-acid battery easily further in a short time by forming a negative electrode strap of a lead alloy containing Ca and Sb, observing a corrosive condition of the negative electrode strap through an optical fiber scope, and detecting a life of the lead-acid battery. CONSTITUTION:In a sealed lead-acid battery, before its use, a surface of a negative electrode strap 8 is smoothed, but when the storage battery is used to be charged/discharged, corrosion is started, and a pattern of lead sulfate appears in a surface of the strap 8. Soon in this surface, irregularity is generated, and further in the end of a life, corrosion is advanced in the strap 8, to increase lead sulfate, so as to generate in the surface an extremely irregular surface. In this condition, an optical fiber scope 16, coated with polyvinyl chloride, is connected to a circuit and inserted from a filler port 12 of the storage battery, to direct an objective lens 17 in a point end of the scope 16 toward the strap 8, and its surface, projected in an eyepiece 18 in the other end of the optical fiber scope 16, is observed to detect color of a surface, whether irregularity is provided or not, and, by a degree thereof, a life of the lead-acid battery.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for detecting the life of a sealed lead acid battery.

[0002]

2. Description of the Related Art Conventionally, in order to detect the life of a sealed lead acid battery provided with an electrode plate group in which a positive electrode plate and a negative electrode plate are laminated via a separator and an electrolyte solution to the extent of impregnating the electrode plate group,
Since it is not possible to adopt the method of measuring the specific gravity of the electrolytic solution like the lead-acid battery with a large amount of free electrolytic solution, disconnect the lead-acid battery from the connection circuit such as the load during use and put it in the inactive state. The life is detected by measuring the internal resistance of the storage battery, performing a high-rate discharge test, or disassembling the storage battery and observing the deterioration state of the storage battery. Further, JP-A-62-52866 proposes a method of detecting the life of a positive electrode plate by measuring the elongation of the positive electrode plate using an index and an optical fiber bundle provided above the negative electrode plate.

[0003]

However, the above-mentioned method for detecting the life of the sealed lead-acid battery has the following problems. (B) Disconnect the storage battery from the circuit,
Instead of the separated storage battery, another storage battery must be prepared and connected. (B) The storage battery must be disassembled. (C) An index must be provided in the storage battery.
Etc., it takes a lot of time and cost, and the storage battery structure must be changed.

[0004]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems of the prior art and aims to detect the life easily and in a short time. The negative electrode strap is made of lead alloy containing calcium and a predetermined amount of antimony. Then, the life of the storage battery is detected by observing the corrosion state of the negative electrode strap with an optical fiber scope.

[0005]

[Function] When calcium and antimony coexist in a lead alloy, an intermetallic compound is formed. This intermetallic compound dissolves in sulfuric acid, and as a result, the lead alloy reacts with oxygen gas and sulfuric acid generated from the positive electrode and the reaction formula shown below. Easily corrodes to produce lead sulfate.

[0006]

[Chemical 1]

[0007]

[Chemical 2]

Due to the production of lead sulfate, the surface of the strap becomes white, then the surface becomes uneven, and the unevenness gradually becomes remarkable. Therefore, the life of the storage battery can be detected by observing this state with an optical fiber scope.

If the amount of the intermetallic compound consisting of calcium and antimony is small, it precipitates at the grain boundaries, and if it is large, it precipitates inside the grains and at the grain boundaries and corrodes the entire surface. Therefore, the corrosion rate and the corrosion mode differ depending on the amount. Therefore, by appropriately controlling the amount, a corrosive state corresponding to deterioration of the storage battery can be obtained.

[0010]

EXAMPLE An example of the present invention will be specifically described below.

As shown in FIG. 1, a sealed lead acid battery is a group of electrode plates in which a plurality of positive electrode plates 1 and negative electrode plates 2 are alternately laminated with separators 3 called retainer mats having excellent liquid holding properties interposed therebetween. 4 and the positive electrode and negative electrode straps 7 and 8 for respectively welding the polar plate ears 5 and 6 of the polar plate group 4 and the battery case 9 that houses these polar plate groups 4. In addition, 10 is a lid for sealing the battery case, 11 is a terminal of the storage battery, 12 is a liquid injection port, 1
Reference numeral 3 denotes a plug body that is screwed into the liquid injection port of the lid to close the liquid injection port 12, and is provided with a safety valve device that safely discharges internal gas to the outside when the internal pressure of the storage battery becomes higher than the above. There is something.

The positive electrode plate 1 is formed by coating and filling a positive electrode active material on a grid substrate made of a Pb-Ca-Sn based lead alloy, for example, Pb-0.1% Ca-0.5% Sn (all are weight ratios, the same applies below). Formed. The negative electrode plate 2 has the same Pb as the positive electrode plate 1.
-Ca-Sn based lead alloy such as Pb-0.1% Ca-
A grid substrate made of 0.5% Sn is formed by coating and filling a negative electrode active material. For the positive electrode strap 7, the electrode plate ears 5 of the plurality of positive electrode plates 1 are set in the concave portion of the strap forming jig having the concave portion, and the positive electrode strap 7 is made of Pb-Sn based lead alloy such as Pb-0.5% Sn. It is formed by welding the electrode ears 5 to each other by injecting the added lead while melting with a burner. Similarly, the negative electrode strap 8 is also formed by melting and injecting lead into the concave portion of the strap forming jig. For example, Pb-30 having antimony as the lead addition is used.
A lead alloy of ppmSb-0.5% Sn was used. By doing so, the negative electrode strap 8 is Pb-0.1% Ca-
Pole of the negative electrode plate made of 0.5% Sn and Pb-30pp
Additional lead consisting of mSb-0.5% Sn melts into a lead alloy with about 0.02% calcium, about 24 ppm antimony and 0.5% tin. As the electrolytic solution, a sulfuric acid aqueous solution was used, and the amount was set so as to impregnate the electrode plate group so that almost no electrolytic solution was liberated.

In the sealed lead-acid battery thus formed, the surface of the negative electrode strap 8 is smooth before use, but when the storage battery is used and charged and discharged, corrosion starts and the surface of the negative electrode strap 8 is exposed. A pattern of lead sulfate 14 appears as shown in FIG. Eventually, the surface becomes uneven, and further at the end of the life, the negative electrode strap 8 is corroded, the lead sulfate amount increases, and the surface becomes a significantly uneven surface 15 as shown in FIG. This state was provided at the tip of the optical fiber scope 16 by inserting the optical fiber scope 16 covered with polyvinyl chloride as shown in FIG. 1 from the liquid injection port 12 of the storage battery which was connected to the circuit and was in a live state. The objective lens 17 is directed toward the negative electrode strap 8, and the negative electrode strap 8 is projected on an eyepiece lens 18 provided at the other end of the optical fiber scope 16.
The surface of the storage battery can be observed, and the life of the storage battery can be detected based on the color of the surface, the presence or absence of unevenness, and the extent thereof.

2 and 3 show the base portion of the electrode plate ear 6 on the lower surface of the negative electrode strap 8.

Although not shown, the optical fiber scope 16 is provided with respective optical fibers of an image guide for observation and a light guide for illumination, an objective lens and an eyepiece lens are provided on the image guide for observation, and one end of the illumination guide. A light source is connected to the light source so that the observed portion can be illuminated from the tip of the light source.

Further, the surface of the optical fiber scope 16 is covered with an electrically insulative and acid resistant substance such as polyvinyl chloride, polypropylene, or polyethylene, and the optical fiber scope is mistakenly attached to the electrode plate group during observation. It was designed to prevent short-circuiting even if they come into contact with each other, and to prevent corrosion by the electrolytic solution.

In order to find a preferable range of the amount of antimony contained in the negative electrode strap, the amount of antimony added to a lead alloy having an amount of calcium sufficient to combine with antimony is 5, 10, 30, 50, respectively. 100,
As a result of floating charging a lead-acid battery equipped with a negative electrode strap changed to 200 ppm at a temperature of 40 ° C. and a voltage of 2.23 V / cell, the amount of change in the corrosion state did not clearly appear at 5 ppm, or 50 ppm or more. In some cases, the surface of the storage battery may have a significantly uneven surface before the life of the storage battery.
Therefore, the preferable amount of antimony is 10 to 30 ppm. In general, a sealed lead-acid battery uses a lead alloy containing calcium as a substrate of an electrode plate, so that it is preferable to regulate the amount of antimony because the amount of components of the negative electrode strap can be easily adjusted.

In the above embodiment, the life is visually detected by looking through the eyepiece of the optical fiber scope. Information from the optical fiber scope is connected to a computer, and the color and area change of the negative electrode strap are used as parameters. The life can also be detected by performing image processing.

Further, in the above-mentioned embodiment, the additional lead containing antimony was used when the negative electrode strap was formed, but it may contain both antimony and calcium.

Further, in the above embodiment, the method of observing by inserting the optical fiber scope into the storage battery by removing the plug at the time of inspection has been described, but the optical fiber scope may be attached in advance by penetrating the lid.

Even if calcium and antimony are added to the positive electrode strap, the phenomenon like the negative electrode strap does not occur and detection cannot be performed.

[0022]

As described above, according to the method of the present invention, by observing the negative electrode strap of a live battery in an active state with an optical fiber scope, the life of the battery can be detected very easily and in a short time, and an indicator or the like can be attached. It is effective in that it does not require a product and does not need to change the structure of the storage battery.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a detection method according to an embodiment of the present invention.

FIG. 2 Partial state diagram of the negative electrode strap during use of the storage battery

FIG. 3 Partial state diagram of the negative electrode strap at the end of life of the storage battery

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Positive electrode plate 2 Negative electrode plate 3 Separator 4 Electrode plate group 6 Electrode plate ear of negative electrode plate 8 Negative electrode strap 16 Optical fiber scope

Claims (3)

[Claims] 1. An electrode plate group in which a positive electrode plate and a negative electrode plate are laminated with a separator interposed therebetween, and a polar electrode plate ear of the electrode plate group are welded to each other while injecting a lead alloy melted by a flame. In a method for detecting the life of a sealed lead-acid battery having a strap, the negative electrode strap for welding the electrode ears of the negative electrode plate to each other is formed of a lead alloy having calcium and antimony, and the corrosion state of the negative electrode strap is determined using an optical fiber scope. A method for detecting the life of a sealed lead acid battery, which comprises detecting the life of the lead acid battery by observing. 2. The seal according to claim 1, wherein the negative electrode strap is formed of 10 to 30 ppm of antimony and a lead alloy having a sufficient amount of calcium to form an intermetallic compound with the antimony. Type lead-acid battery life detection method. 3. The method for detecting the life of a sealed lead-acid battery according to claim 1 or 2, wherein the optical fiber scope is covered with an electrically insulating and acid-resistant substance.