Lead-acid battery structure and use -Lithium - Ion Battery Equipment
Lead-acid batteries
1. Plates of lead-acid batteries
The pole plate is divided into positive plate and negative plate, both of which are composed of grid frame and active material.
The purpose of the grid.
The ladder has a secondary purpose, which will accelerate the precipitation of hydrogen and accelerate the consumption of the electrolyte, and it is also easy to be introduced from the positive plate grid, causing self-discharge and grid corrosion of the battery, shortening the service life of the battery. At present, most of the grids at home and abroad use low brocade alloy grids (with a ladder content of 2%-3.5%) or lead-calcium alloys as grids.(Lithium - Ion Battery Equipment)
The active material on the positive plate is lead dioxide (Pb02), which is dark brown; the active material on the negative plate is sponge-like pure lead (Pb), which is blue-gray. The active material is mixed into a paste and filled in the gaps of the grid frame and dried to form the electrode plate.
Immerse the positive and negative plates in the electrolyte to obtain an electromotive force of about 2V. In order to increase the capacity of the battery, multiple positive and negative plates are often connected in parallel to form a positive and negative plate group, as shown in the figure (drawing). In each single-cell battery, the number of positive plates is one less than that of negative plates, so that each positive plate is located between two negative plates, so that the two sides of the positive plate can be discharged evenly, and the Plate arches.
2. Separator for lead-acid batteries
The separator is inserted between the positive and negative plates, and its purpose is to prevent the positive and negative plates from contacting each other and causing a short circuit. The separator should be acid resistant and porous to facilitate the penetration of the electrolyte. Commonly used separator materials are wood, microporous rubber and microporous plastic. Among them, the wood clapboard has poor acid resistance and has been eliminated. Microporous rubber separators have the best performance but higher cost. Microporous plastic separators have small apertures, high porosity and low cost, so they are widely used.
When installing, the grooved side should face the positive plate and be perpendicular to the bottom of the casing. At the same time, the groove can dredge the electrolyte up and down, so that the air bubbles can rise along the groove. Covering the positive plate can prevent the active material from falling off.
3. Electrolyte
In the chemical reaction of the lead-acid battery, the electrolyte plays the role of conduction between ions and participates in the chemical reaction of the battery. The electrolyte is prepared by pure sulfuric acid (H:S0.) and distilled water in a certain proportion, and its density is generally 1.24~1.30g/cm’. Select electrolyte density according to season and region. The liquid level should be 10-15mm higher than the upper plane of the pole plate (partition plate).
4. The shell of the lead-acid battery
The shell is used to hold the electrolyte and the plate group, and should be resistant to acid, heat and shock. The shell is mostly made of hard rubber or polypropylene plastic, which is an integral structure, and there are raised ribs at the bottom to place the pole plate group. The inside of the shell is divided into 3 or 6 cells that do not communicate with each other by the partition wall, and the cells are connected in series with lead bars (pictured). The upper part of the casing is sealed with a battery cover of the same material, and the battery cover is provided with a liquid filling hole corresponding to each single cell for adding electrolyte and distilled water, as well as measuring the density, temperature and liquid level of the electrolyte. The ventilation holes on the filler hole cover allow the gas that occurs in the chemical reaction of the battery to be discharged smoothly.
Link: The purpose of the link is to connect the single-cell battery in series in order to increase the terminal voltage of the middle battery
5. The pole of lead-acid battery:
In general, there are three types of terminals welded on the horizontal plates of the first and last two-pole plates of the battery, the terminal type, the conical type and the I-shaped type. In order to facilitate the difference, the positive terminal is marked with a + or p mark, and some terminals are painted Has red paint and has a - or N mark on the negative post. Can be measured with a voltmeter when it is unclear.