JPH01149374A - Manufacture of sealed lead-acid battery - Google Patents

Abstract

PURPOSE:To obtain a lead-acid battery having large discharge capacity by forming a space, into which oxygen gas can freely be penetrated, between an electrode group obtained by combining plates and a porous separator and the inside of a container, and making a free electrolyte to exist in only the pores in the electrolyte group when the battery is electrochemically activated. CONSTITUTION:An electrode group is formed with unformed plates 1, 2 of a sealed lead-acid battery and a mat-like separator 3 having high liquid absorbency and placed between plates 1, 2. Ribs 7 are installed so that a space is formed between the flat part of the anode plate 2 and the inner wall of a container 6 when the electrode group is inserted into the container 6. An electrolyte is poured in the container 6 so that the free electrolyte exists, and the container is sealed with a check valve 8 to prevent gas flow into the battery, then in- container formation is conducted. The quantity of electricity by which practically no free-electrolyte exists in the container after the formation has been completed is passed. The large amount of electrolyte exists in the battery and the lead-acid battery having large discharge capacity is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a new method for manufacturing sealed lead-acid batteries.

Prior Art The basic structure and manufacturing method of sealed lead acid batteries are generally well known, for example, as disclosed in U.S. Pat. No. 3,862,
No. 861 proposes a battery construction method using highly absorbent galanumat as a separator, and U.S. Pat. Proposed.

Furthermore, prior to the invention of the aforementioned U.S. patent, S. Hills et al.
In a sealed lead-acid battery, a space is provided between the inner surface of the battery case and the electrode plate group, and the cathode surface of the electrode plate group is exposed to this space. Efficiently recombines oxygen gas generated during overcharging (
clarifies the content that can be absorbed). Furthermore, S. and Hills et al. have also shown that it is desirable to have as much electrolyte as possible in the separator portion between the anode and cathode plates.

Problems to be Solved by the Invention However, both the above-mentioned US Pat. No. 3,862,861 and S. Hills et al. do not mention anything about battery case formation.

U.S. Pat. No. 4,648,177 proposes a method for applying cell formation to sealed lead-acid batteries, but in this proposal, sufficient free liquid is present at the beginning of cell formation. There is no suggestion or mention of the advantages of carrying out battery cell formation with the battery sealed with a safety valve that only allows gas to be discharged from inside the battery to the outside of the battery.

The present invention aims to provide a sealed lead-acid battery in which the electrode plates are chemically formed using a battery case formation method, which has a larger discharge capacity than a conventional method in which a convex projection is not provided on the inner surface of the battery case. .

Means for Solving the Problems The present invention is to manufacture a sealed lead-acid battery of cathode gas absorption type, which is normally in a sealed state, by the method described below.

(a) An electrode plate group is composed of unformed lead-acid battery monthly electrode plates and a highly liquid-absorbent mat-like separator inserted between the electrode plates.

(b) Insert the electrode plate group constructed in (a) into the battery case.

However, at this time, so that there is a space between the flat surface of the cathode plate on the outside of the electrode plate group and the inner wall surface of the battery case, there is a convex protrusion (a so-called lip) on the inner wall surface of the battery case. will be established.

(C) Attach the lid to the battery case.

(d) Inject dilute sulfuric acid, which is an electrolytic solution, into the battery container in an amount sufficient to ensure that free solution exists.

(e) Use a safety valve (check valve) that allows gas from inside the battery case to be discharged to the outside of the battery when the pressure exceeds a specified level, but does not allow gas to flow into the battery from outside the battery. to seal the battery case.

(f) Cartridge formation is carried out, and at the end of this formation, an amount of electricity is applied such that there is virtually no free electrolyte in the tank.

Another feature of the present invention is to provide a sealed lead-acid battery with a large discharge capacity that is sealed under normal conditions due to the oxygen gas cycle inside the battery case. Here, the battery case includes at least one porous anode plate and at least one porous cathode plate, and the negative and positive electrode plates are electrochemically converted and activated in the battery case. . The outer surface of the electrode plate group is configured such that the cathode plate is located on at least one surface thereof, and a space large enough to allow gas to freely flow is provided between the cathode plate and the inner wall surface of the battery case. It will be done. Then, dilute sulfuric acid, which is an electrolytic solution, is injected in an amount sufficient to fill the space provided between the above-mentioned electrode plate group and the inner wall surface of the battery case (an amount in which there is a sufficient amount of free liquid), and the battery cell chemical composition is completed. The purpose of this process is to ensure that there is virtually no free liquid.

Function The present invention will be explained in detail with reference to FIG. In the figure, 1 is an unformed anode plate obtained by filling a lead alloy grid with a paste mainly consisting of an electrochemically active lead compound;
2 is an unformed cathode plate obtained by filling a lead alloy grid with a paste mainly consisting of lead powder, a lignin compound, and barium sulfate, and 3 is a cathode plate made by mixing synthetic resin fibers mainly consisting of fine galanu fibers. 4 and 6 are lead bodies from the anode plate and the cathode plate, respectively. 6 is an ABS resin battery case, and 7 is a convex projection formed integrally with the battery case 6 and is in contact with the surface of the cathode plate 2. Note that a space is formed between the cathode plate 2 and the battery case 6 via the lip 7, and this space is large enough to allow oxygen gas generated from the anode plate to freely enter. It is necessary to select the height of the lip 7 so as to form the shape. Reference numeral 8 is a safety valve made of chloroprene rubber, which opens only when the pressure inside the battery exceeds a predetermined value, exhausting gas from inside the battery to the outside, and preventing gas from entering the inside of the battery from outside the battery. shall have the function of blocking.

Each component in FIG. 2 is the same as that shown in FIG.

The lattice body of the lead alloy bag used in the anode and cathode plates 1 and 2 can be obtained by a casting method or by processing a lead plate into a perforated or expanded shape. . It is desirable that the lead used in the grid body contains as little impurities as possible that reduce the hydrogen overvoltage, especially at the cathode, and is preferably a lead-calcium, lead-calcium-tin-based alloy or similar alloy that has an inherently high hydrogen overvoltage. is good.

1E A chemically active pasty active material is filled into the negative and positive polar lattice bodies by a conventionally known method. Next, the obtained anode plate and cathode plate are aged in a predetermined humidity and humidity, and are brought into a dry state.

Next, the anode plates, separators, and cathode plates are alternately stacked to form an electrode plate group. Here, lead bodies (lugs) 4.6 are welded to each of the anode and cathode plates.

Next, the electrode plate group is inserted into the battery case, and the battery case is sealed so that only the part where the safety valve 8 is installed is left in an air-tight and liquid-tight state.

Inject dilute sulfuric acid (20° C.) with a specific gravity of 1.15 to 1.32 into the storage battery shown in FIG. The safety valve 8 is used to seal the storage battery.

The amount of sulfuric acid added is approximately 4.0% per 1Ah of discharge capacity of a single cell.
It is desirable to set it to 0 to 6.0 degrees, more preferably about 4.6 to 6.4 degrees.

As an example, specific gravity is 1.225 (20
9 to 15 g of dilute sulfuric acid. F can be used.

Here, the electrolytic solution can be efficiently injected into the battery case under reduced pressure after the gas in the battery case has been exhausted, but this is not necessarily necessary, and the electrolyte can be sufficiently injected even under normal pressure. The injected electrolyte is sufficiently present in the height direction of the electrode plate group to fill the space formed by the battery case lip 7 and the cathode plate 2, and the liquid level is made to exceed the upper end of the separator 3. be able to. Next, after attaching the safety valve 8 and sealing the battery, the electrode plates are chemically activated by vapor chemical formation in the container, forming lead dioxide on the anode plate and spongy metallic lead on the cathode plate. Ru.

The energization method during chemical formation is the constant current method with 9 stages.

A desired method can be freely selected and used, such as the oblique current method. The amount of electricity applied during formation is such that there is virtually no free electrolyte in the battery, and the electrolyte used during formation is allowed to act as the final battery electrolyte, and at the end of formation it is The individual pores in the plates and separators are generally sufficiently filled with electrolyte.

However, in this case, the side of the cathode plate 2 facing the inner wall of the battery case (which is forcibly separated from the inner wall of the battery case by the lip 7 and exposed in the space) is exists in an exposed form in the space, so even if the pores inside are essentially filled with electrolyte, they are covered with a thin film of electrolyte. It is thought that this acts extremely effectively on the recombination (disappearance) of oxygen gas in the cathode plate.

The separator used in the present invention is extremely fine (0.1 to 10
Galanu fiber alone with a fiber diameter of about 2 μm, or glass fiber with synthetic resin fibers such as acrylic or polyester (fiber diameter of 2 μm or more)
A mat-like porous material mixed with paper (preferably a diameter of about 20 μm, preferably as small as possible) is used. The synthetic resin fiber used here increases the mechanical strength of the obtained separator to make it easier to handle, and its highly water-repellent property prevents oxygen gas generated from the anode plate during chemical formation and overcharging. This makes it easier for oxygen gas to escape from between the anode plate and the separator to the outside of the electrode plate group, and this escaped oxygen gas permeates into the space between the cathode plate and the battery case lip and is absorbed by the cathode plate. Effective.

Examples Example 1 With the configuration shown in the figure, six single cells of the same type with rated capacities s and oA h were each assembled. Here, we proceeded with the work by making sure that all types of anode plates, cathode plates, and separators had the same content.

The anode plate is a known paste-type unformed electrode plate with a thickness of 3.3,
The cathode plate is a known paste-type unformed electrode plate with a thickness of 2.0 mm.
The separator is made of 95 glass fibers with an average fiber diameter of approximately 0.8μ.
wt% and 5w of acrylic resin fibers with an average fiber diameter of about 7μ
It is a porous material mixed with t% and has a thickness of 2.3 m and a porosity of approximately 92 cm when assembled in a battery case in a compressed state. The height of the container is 0.2 m, 0.5 m.

1.0m + 03 types, and for comparison, we also prepared battery cases with a lip height of Owm (without lip), and placed electrode groups in a total of 4 types of battery containers (6 batteries for each lip height). are installed in each case, and the valve holes are sealed to be liquid-tight and air-tight except for the valve hole where the safety valve 8 is installed. Next, specific gravity 1.23
0 (20 u) of dilute sulfuric acid is injected, and a safety valve 8 is attached to the valve hole to prevent oxygen gas from flowing into the battery from outside the battery. When the dilute sulfuric acid injection is completed, the liquid level of the dilute sulfuric acid in the battery is above the upper end surface of the separator 3, and there is no dilute sulfuric acid in the battery other than the amount that can be absorbed by the electrode group. This is a state in which a sufficiently large amount of free dilute sulfuric acid is present. Next, each battery is energized in this state with a constant current of o, eA for 36 hours. As a result of this energization, the water in the dilute sulfuric acid is electrolyzed to the point where there is virtually no diluted sulfuric acid in the free liquid state in batteries of any lip height.

After completion of chemical formation, each cell has a temperature of 0.7 at 25°C.
It was subjected to a 5A (0.25C) discharge test.

As a result, when the lip height is 0.2 wm, the average discharge time is 1
When the lip height is 0.5 m, the average discharge time is 20 g minutes, when the lip height is 1.0 mm, the average discharge time is 200 minutes, and when the lip height is Oam (when there is no lip), the average discharge time is 20 g minutes. The time was 182 minutes.

Example 2 Basically the same configuration as Example 1, but with three anode plates,
By stacking four cathode plates alternately with separators in between, cells of the same type with a rated capacity of 9.0Ah can be made.
Make 5 of each. Note that the anode plate, cathode plate, and separator used here are the same as those used in Example 1. The height of the container is 0.3 yap, 0.6 m.
m, 1.0+m, and for comparison, we also prepared a battery case without a rig and a lip height of OH), making a total of 4 types of battery containers (5 batteries for each lip height). Incorporate the electrode plate groups into each.

As an electrolyte, dilute sulfuric acid 86 with a specific gravity of 1.230 (20°C)
Inject m1 and attach a safety valve to the valve hole. Note that when the dilute sulfuric acid injection is completed, the liquid level of the dilute sulfuric acid in the battery is higher than the upper end surface of the separator. Next, each battery has 2. The battery is formed using a constant OA current for 32 hours. As a result of this battery cell formation, the water in the dilute sulfuric acid is electrolyzed and the liquid volume is reduced to the point where there is virtually no dilute sulfuric acid in the free liquid state in batteries of any lip height.

After the completion of chemical formation, each cell was heated at 26°C with a temperature of 0.
It was subjected to a discharge test of 9A (0, IC).

As a result, when the lip height was 0.3 m, the average discharge time was 10.
23 hours, average discharge time 10 when lip height is 0.6fi
．． 32 hours, average discharge time 1 when lip height is 11flI
It is 0.29 hours and the reply height is 0 (if there is no reply)
At the time of , the average discharge time was 9.96 hours.

Effects of the Invention As described above, the application example of the present invention can provide a storage battery with a larger discharge capacity than the conventional example (comparative example). The reason why this good result is obtained is that during the formation of the battery cell, the water in the electrolyte decreases due to electrolysis as electricity progresses, and the electrolyte level drops, exposing the cathode and anode plates from the solution. In this case, the cathode plate located at the outermost side of the electrode plate group is exposed in the gap between it and the inner wall of the battery case, and the acid generated from the separator plate during charging flows to this exposed surface. This is thought to be because the elementary gases reach the electrolytic solution smoothly and are absorbed and recombined, thereby suppressing the decomposition and reduction of water in the electrolytic solution.

When the reduction in water decomposition is suppressed, there will be a relatively large amount of electrolyte in the anode plate, cathode plate, and separator in the electrode plate group, which is sufficient for reaction, and the anode plate, cathode plate, and separator will be The pores are filled with the electrolyte in good condition, so the current applied by electrochemical formation acts efficiently, and the unformed active material can be efficiently converted into an electrochemically active active material. It is thought that this is because of this.

[Brief explanation of the drawing]

FIG. 1 is a schematic vertical cross-sectional view of a storage battery according to the present invention, and FIG. 2 is a schematic cross-sectional view taken along line AN in FIG. 1. 1... Anode plate, 2... Cathode plate, 3...
... Separator, 4 ... Anode lead body, 6
... Cathode lead body, 6 ... Battery case, 7.
...Rib, 8...Safety valve. Name of agent: Patent attorney Toshio Nakao and one other name
2 figure

Claims (4)

[Claims] (1) An electrode plate group is constructed by combining an electrochemically unformed lead acid battery electrode plate and a highly porous separator, and the surface of the cathode plate is positioned on at least one outer side of this electrode plate group. , the inner surface of the battery case is provided with a convex protrusion that comes into contact with the cathode plate located on the outer surface of the electrode plate group when the electrode plate group is inserted therein, so that the electrode plate group and the inside of the battery case are connected to each other. A space is formed between the surface and the surface where oxygen gas can freely permeate, and the space formed by the electrode plate group, the inner surface of the battery case, and the convex protrusion is sufficiently filled, and the amount existing in a free state is Controlled dilute sulfuric acid is injected into the battery, the battery is sealed with a safety valve, and the built-in electrode plates are electrochemically activated through battery formation, while the free electrolyte in the battery is A method for manufacturing a sealed lead-acid battery, characterized in that the pores in the electrode plate group are controlled so that they are substantially absent except for those that are sufficiently filled. (2) In claim 1, the amount of sulfuric acid injected into the battery is approximately 4.0 to 6.0 per Ah capacity of the cell.
A method for manufacturing a sealed lead-acid battery, characterized in that g. (3) The method for manufacturing a sealed lead-acid battery according to claim 1, wherein the highly porous separator is a mat-like porous body composed of fine glass fibers and synthetic resin fibers. (4) The method for manufacturing a sealed lead-acid battery according to claim 3, wherein the synthetic resin fiber is an acrylic resin fiber or a polyester resin fiber.