Curing process for negative plate of lead acid battery

Abstract

The present invention discloses a curing process for a negative plate of a lead acid battery. The curing process comprises an oxidation stage and a drying stage, wherein the oxidation stage comprises the following steps: an initial step: maintaining a temperature of 50 DEG C, a relative humidity of not less than 98%, and time of 3-5 hours; a temperature raising and humidity decreasing step: raising the temperature for 3-5 DEG C each time, decreasing the relative humidity by 2%-4%, maintaining for 3-5 hours after temperature raising and humidity decreasing, and finally, raising the temperature to 60 DEG C; and a temperature raising and cooling step: firstly, raising the temperature for 5-10 DEG C each time, maintaining for 4-8 hours after temperature raising, raising to a highest temperature of 75 DEG C, then cooling for 3-5 DEG C each time, maintaining for 3-5 hours after cooling, cooling to the lowest temperature of 65 DEG C, and maintaining the humidity to be not less than 95% in the step. According to the curing process disclosed by the present invention, by optimizing process parameters, an electrode plate is guaranteed to be oxidized in the shortest time, the crystallization effect of active substances of the electrode plate is guaranteed to be the best, the strength of the electrode plate is obviously improved, the fragmentation rejection rate is reduced by nearly 1%, and the time of the curing process is shortened to two days.

Description

technical field [0001] The invention relates to the field of lead-acid battery manufacturing, in particular to a curing process for a lead-acid battery negative plate. Background technique [0002] In the manufacturing process of lead-acid batteries, the curing of the plates is one of the main cores. After the grids are filled with lead paste, only through the curing process can the particles of the lead paste be connected to each other to form a continuous and solid skeleton, and tightly attached to the plates. on the fence. The solidification of the plate directly affects the performance index and service life of the battery. At present, the outstanding problems of the plate are poor plate strength and poor consistency of plate indicators. [0003] Plate curing is divided into two stages of oxidation and drying. The oxidation process is mainly completed: (1) Oxidation of free lead to increase the capacity of active materials; (2) Oxidation of lead on the surface of grid ...

AI Technical Summary

Problems solved by technology

Since Pb (density is 11.34g / cm 3 )→PbSO 4 (Density is 6.32g / cm 3 )→PbO 2 (density is 9.37g / cm 3 ) during the conversion process, the volume changes a lot, and the plate after curing by the existing curing process will cause the plate to bend and the active material to fall off due to the stress generated by the internal volume expansion of the plate during the formation process

At the same time, due to the increase in the volume of the active material, the porosity of the active material will decrease, so that the oxygen generated during the formation of the positive plate is not easily transported to the surface of the plate and overflows, and accumulates inside the plate to generate pressure. Oxygen overcomes the resistance of the liquid in the gap from the inside of the plate, and has a scouring effect when moving to the surface of the plate, causing the active material to fall off and shortening the service life of the battery

[0006] Analysis of the main defects of the traditional curing method: (1) The plate curing is placed in a horizontal manner, the distance between the plates is small, the oxygen enters and transmits slowly, and the heat released by the plate oxidation is difficult to get rid of, resulting in plate oxidation slow

(2) Due to the design requirements of the battery itself, the thickness of the negative plate is relatively thin. During the curing and drying process, due to the unreasonable placement and high curing temperature, it is easy to cause the plate to bend

(3) The middle and lower, left and right, front, middle and rear plates in the curing room have a large gap in the water loss rate and free lead content at each curing stage, and the strength of the plates cannot meet the process requirements, resulting in a high scrap rate

(4) The curing and drying cycle is long, which affects the turnover of the curing room and reduces production efficiency

[0007] At present, many manufacturers have proposed high-temperature curing technology, which can greatly shorten the process time, but the plates made by the existing high-temperature curing technology have the problems of low bonding strength of active materials and short service life.

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