Lead-acid battery self-discharge

Date:Aug 12, 2019

Lead-acid battery self-discharge

Reasons for abnormal self-discharge of lead storage batteries

1. The electrolyte is mixed with metal impurities, especially those mixed with metal impurities higher than the lead potential, which is more harmful. For example, copper is mixed into the electrolyte, which is attached to the negative plate and forms a small battery with lead. The copper is the positive electrode, the lead is the negative electrode, the current is from copper to lead, and then the electrolyte returns to the copper to form a closed circuit and discharge itself.

2. The battery separator or the outer wall of the outer casing is broken and the active material of the electrode plate is severely detached. If the separator is broken or the active material of the plate is severely detached, the positive and negative electrodes of the single cell will be short-circuited; if the partition wall of the outer casing is broken, the positive and negative poles between the single cell and the single cell will be short-circuited. These can cause severe self-discharge.

3. The battery cover is cracked or the seal is not tight, and the surface is wetted by the electrolyte, causing the positive and negative terminals of the single cell to be short-circuited. Produces self-discharge.

Measures to prevent abnormal self-discharge

1. When preparing the electrolyte, apply concentrated sulfuric acid and distilled water with higher purity. Although ordinary industrial sulfuric acid is cheap, it contains a lot of impurities unless it is necessary to use it to prepare an electrolyte. In difficult conditions, when there is a lack of distilled water, it can be replaced by clean rain and snow. Generally, well water contains more minerals and should not be used to prepare electrolyte. The container containing the electrolyte must be made of ceramic, glass, plastic or pure lead. It is not allowed to hold the electrolyte in a steel or iron container.

2. Pay attention to keep the battery surface clean and dry. If the upper cover is wet or dirty by the electrolyte, it can be rinsed off with hot water. When conditions permit, it can be wiped with an alkaline solution such as sodium carbonate (soda) or fluorine water, and then a thin layer of butter is applied to the outer surface of the terminal to prevent sulfide and oxide from forming at the terminals and increase the electrical resistance.

3. Do not overcharge the high current for a long time while charging.

4. When the lead battery fails to self-discharge, the electrolyte in the battery can be poured out, the sealing glue is burned, the plate group is taken out, and the plates and separators are washed with distilled water to remove the mixed metal impurities. Repair or replace the damaged casing, plates and partitions, then refill as required and add a neat new electrolyte. After being charged by the initial charging method, it is delivered for use.

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