JP3099356B2 - Battery forming method for sealed lead-acid batteries - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of forming a battery case for a sealed lead-acid battery, and more particularly, to a battery case in which the shape of a rib provided on the inner wall of a cell and the current density of a charging current at the end of formation are improved. It relates to a chemical formation method.

Conventional technology In conventional battery case formation, even after the charge progresses and the negative electrode potential becomes lower than that of the cadmium electrode (hereinafter referred to as “inversion”), the formation is performed at the same current density (about 0.72 A / dm ² ). Therefore, the role of the ribs provided on both sides of the inner wall of the battery case opposite to the negative electrode plate was simply to make it easier to insert the electrode plate into the battery case, and the height of the ribs was also about 0.1 mm. .

Problems to be Solved by the Invention To improve the capacity of a sealed lead-acid battery,
When increasing the electrode plate height to increase the electrode plate, increasing the electrode plate height causes the electrolyte surface to rise, causing the liquid surface to rise due to gas generation during charging during battery case formation and overflowing the electrolyte. Therefore, the amount of electrolyte solution that can be injected is restricted. Also, the amount of charged electricity must be increased, and during the formation of the battery case, the electrolyte is lost due to gas generation, and the amount of electrolyte required for the battery is reduced despite the increase, so the capacity does not come out and the same battery case is used. There was a limit in improving the capacity.

The present invention solves the conventional problems as described above, and makes the electrode plate larger by increasing the height than the conventional one. It is an object to provide a battery case formation method.

Means for Solving the Problems To solve this problem, the battery container forming method of the sealed lead-acid battery according to the present invention comprises: After inversion of battery formation performed by injecting an electrolyte into an uncharged battery comprising an unformed electrode plate, which was accommodated in the cell provided with two or more ribs, the current density of the charging current was 0.2 A / dm. ² or less.

According to such a method, the electrolyte can be efficiently formed with little decrease in the electrolytic solution during the formation of the battery case. This is because a gap is created between the battery case and the electrode plate by providing two or more ribs with a height of 0.3 mm or more on both sides of the inner wall of the battery case opposite to the negative electrode plate during charging. This facilitates the diffusion of the generated oxygen gas into the gap, thereby promoting the gas absorption reaction with the negative electrode plate. Alternatively, by providing a rib having a height of 0.3 mm or more, the liquid injection at the initial stage becomes smooth and the liquid does not overflow. Also, in terms of battery performance, the electrode plate can be made higher in shape than before so that high-rate discharge is improved, and the charging effect is higher because it is charged at a lower current density, and the charged amount of electricity is 80% of the conventional amount and the current The same capacity can be obtained.

Embodiment Hereinafter, a method for forming a battery case of a lead storage battery according to an embodiment of the present invention will be described in detail with reference to the drawings.

The battery used was a 6V, 4Ah (20HR) sealed lead-acid battery. The configuration of the electrode plates was two for the positive electrode plate and three for the negative electrode plate, and the dimensions of the electrode plates were both the same. FIG. 1 shows the shapes and positions of the ribs 1 provided on both sides of the current inner wall facing the negative electrode plate this time. The rib 1 was provided from a position 15 mm from the upper end of the battery case 2. The upper corner is dropped to make it easier to insert the plates. A total of two ribs 1 were provided in the lateral direction at a distance of 13 mm from the center 3 of the cell. The height 4 of the rib 1 is 0.
3 mm. In the battery case formation method, first place the electrode group consisting of unformed electrode plates in the same battery case as before, and inject 34 cc / cell of a dilute sulfuric acid electrolyte with a specific gravity of 1.235, which is about 10% less than before,
The battery is charged at a constant current of 0.8 A, and discharged at 0.8 A for 1 hour at 12 hours after the start of energization as in the embodiment shown in FIG. After discharging, the battery is charged again at 0.8 A for 4 hours, and then the current value is reduced to 0.2 A (about 0.18 A / dm ² ), and charging is performed for 49 hours. This time, the reason why the current density after the reversal in the final stage of chemical formation was reduced to 0.2 A / dm ² or less will be described. As the charge of the positive electrode nears completion, the lead-acid battery generates O ₂ gas by the following reaction.

2H ₂ O → O ₂ + 4H ⁺ + 4e ⁻ (1) In a sealed lead-acid battery, O ₂ generated reacts with Pb generated at the negative electrode from charging to form PbO.

2Pb + O ₂ + H ₂ SO ₄ → PbO + PbSO ₄ + H ₂ O (2) However, in the conventional battery case formation, the O ₂ gas has a high current density during formation (because of poor reaction efficiency and a large charging current). The negative electrode (especially the end plate) is hardly able to absorb the O ₂ gas, so that a large amount of the electrolyte solution is reduced during the formation. Therefore, in order to prevent the electrolyte solution from decreasing as much as possible and to promote the formation, it is necessary to find a current density at which the reactions of the equations (1) and (2) are in equilibrium. FIG. 3 shows the result of examining the weight loss of the battery by changing the current density after the inversion at the end of chemical formation. The total amount of charge at each current density is the same. As a result, since the weight decreased at the current density of 0.2 A / dm ^2, a current density of 0.2 A / dm ² or less was adopted. Next, the height 4 of the rib 1 in FIG. 1 is determined. The two negative electrodes on the end plate absorb the O ₂ gas most easily, but the O ₂ gas is diffused if the inner wall of the battery case and the negative electrode plate are stuck together. The diffusion effect was observed by changing the height 4 of the ribs 1. The result is shown in FIG. From FIG. 4, it is understood that the height 4 of the rib 1 needs to be 0.3 mm or more. 0.2mm Hereinafter, it is believed that the rib 1 cause significant weight loss diffusion is less likely to be of the O ₂ gas to hardly a gap in biting the container inner wall and the negative electrode plates to the paste 1. Further, the results regarding the battery capacity are shown in FIG. In the battery case formation method of the present embodiment, the charging effect is increased because the battery is charged at a low current density at the end of charging, and the total charge amount is about 80% of the conventional one, and the same capacity as the conventional one can be obtained. Weight has also been reduced by half.

As described above, ribs with a height of 0.3 mm or more are provided on both sides of the inner wall of the container opposite to the negative electrode plate, and the current density of the container formation is 0.2 A / dm ² or less after the inversion of the last stage of formation. In this case, the Neumann reaction can be promoted at the negative electrode of the end plate, and the weight loss during battery case formation can be reduced, so that the electrode plate can be enlarged accordingly. In addition, since the current value is significantly reduced after the end of the chemical conversion, the battery formation time is prolonged. However, the amount of electricity charged is about 80% of the conventional capacity, and the same capacity as the conventional one is obtained, which also reduces the cost. Further, from the results described above, according to the present embodiment, it is possible to obtain a prospect that the electrode plate height will be slightly higher than the conventional electrode plate even if the same battery case as the conventional one is used in the future, and the capacity will be increased. Was.

Effects of the Invention As is apparent from the above description of the embodiment, according to the battery case formation method for a sealed lead-acid battery of the present invention, the battery case formation is performed by injecting an electrolyte into an uncharged battery comprising an unformed electrode plate. In the formation, the current density was 0.2 A / dm ² or less after the inversion, and on both sides of the inner wall of the battery case of each cell facing the negative electrode plate.
By providing two or more ribs with a height of 0.3 mm or more, a gap is provided between the negative electrode plate and the inner wall of the battery case, and the formation efficiency of the battery case is increased by forming a battery case in which the electrolyte is secured. It was possible to greatly reduce the amount of electrolyte solution reduced during battery case formation. Therefore, even if the same electrode is used in the future,
The height of the electrode plate is increased to increase the size of the electrode plate so that the capacity of the sealed lead-acid battery can be formed without any problem even if the capacity is increased.

[Brief description of the drawings]

FIG. 1 shows the position and shape of a rib in a battery case forming method for a lead-acid battery according to one embodiment of the present invention, where (a) is a side view of the rib and (b) is A, A 'of (a). FIG. 2 (c) is a cross-sectional view of a rib in which a main part of FIG. 2 (b) is enlarged. FIG. 2 is a graph showing the relationship between charge and discharge currents during battery formation, battery voltage and formation elapsed time. FIG. 3 is a graph showing the relationship between the terminal current density (after reversal) and the weight loss of the battery during formation of the battery case;
FIG. 4 is a graph showing the relationship between the height of the rib and the weight reduction of the battery during battery case formation. FIG. 5 is a diagram showing a battery case formation method for a sealed lead-acid battery according to one embodiment of the present invention and a conventional battery case formation. 4 is a graph showing a comparison between battery capacity and weight loss during battery formation in the method.

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Claims (1)

(57) [Claims] 1. An unformed electrode plate comprising two or more ribs having a height of 0.3 mm or more provided on both sides of the inner wall of a battery case of each cell opposite to the negative electrode plate. A method for forming a sealed lead-acid battery in which the current density of the charging current is reduced to 0.2 A / dm ² or less after inversion of the battery formation performed by injecting an electrolytic solution into the rechargeable battery.