Reasons For The Production Of Folded Lead Batteries
- Sep 18, 2018 -

In view of the particularity of lead-acid batteries for electric bicycles, various battery manufacturers have adopted various methods. The typical approach is as follows:

1. Increase the number of plates.

We changed the design of the single grid from 5 to 6 to 6 to 7, 7 to 8, and even 8 to 9. Increase the number of plates to increase the battery capacity by reducing plate thickness and separator.

2. Increase the proportion of sulfuric acid in the battery

The proportion of sulfuric acid in the original floating battery is generally between 1.21 and 1.28, while the proportion of sulfuric acid in the battery of electric bicycle is generally around 1.36 to 1.38, which can provide large current and improve the initial capacity of the battery.

3. Increase the amount and proportion of lead oxide, the active material of positive plate.

Adding lead oxide increases the electrochemical reaction involved in the discharge, which increases the discharge time and the battery capacity.

Through these measures, the initial capacity of the battery meets the capacity requirements of the electric bicycle, especially improving the characteristics of large current discharge of the battery. However, as the plate increases, the capacity of sulfuric acid decreases, the battery heats up and loses a lot of water. Increasing the proportion of sulfuric acid increases the initial capacity of the battery, but the vulcanization is more serious. One of the most basic principles of a sealed battery is that after the positive plate is dissolved, oxygen goes directly to the negative plate and is absorbed by the negative plate and reduced to water. In this way, the battery's water loss is very little, achieving "maintenance free", is free of added water.

To this end, the negative plate capacity to do more than the positive plate capacity, also known as the negative transition. The increase of active material of positive plate will inevitably result in reduction of negative electrode transition, deterioration of oxygen cycle and increase of water loss, which will lead to vulcanization. Although these measures increase the initial capacity of the battery, they will result in the loss of water and vulcanization, which in turn will promote each other, ultimately sacrificing the battery life.

There is also the problem of assembly - void welding. The spot that produces imaginary welding easily is plate. Each battery cell has 15 plates, that is, 15 solders, one battery has 6 bars, that is 90 solders, and one battery cell consists of 3 12V cells, that is 270 solders. If a solder spot has false solder, the capacity of the cell will decrease, and the cell will form a battery backward, resulting in the entire battery backward, the battery will form a serious imbalance, leading to the premature failure of this battery. Even if virtual welding is controlled to one part per ten thousand, an average of 37 batteries will have virtual welding, which is absolutely not allowed. Many battery manufacturers prefer to use a low antimony alloy grid over a lead-calcium alloy grid, which can separate out calcium during welding and mask the problem of spot-welding. However, the low antimony alloy plate gate oxygen and hydrogen evolution voltage is lower, the gas output of the battery is large, water loss is relatively serious, and the battery is easier to vulcanize.


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