Lead savings and battery grid life
With lead prices rising, cost has become an important issue in battery production. How to reduce costs has become a problem that technicians need to consider. The grid plays the role of conducting electricity and supporting active substances, and does not directly store electrical energy, nor is it the core substance that participates in chemical reactions. Therefore, how to make the grid play the best performance and reduce the corresponding weight of the grid is an eternal topic.
In the past, the price of lead was low, and the grid design was mostly over-functional. For starter batteries, the grid used to design accounted for between 35% and 45% of the weight of the plate, and the proportion of large and medium-sized valve-regulated batteries was basically the same. Now the weight of the grid is gradually reduced. At present, the grid for starting batteries (gravity casting) accounts for 26%~35% of the weight of the plate, while the large and medium valve-regulated batteries account for 28%~42%. If the weight of the grid is reduced too much, the performance of the battery will be reduced, the life of the battery will be shortened, and it will be difficult to form the grid by gravity casting, and it will be difficult to carry out production.
A large number of anatomical tests have found that when the normal battery life ends, the battery grid is almost completely corroded, and sometimes the alloy is not seen, or the alloy is very small, and it is broken into small pieces when it is slightly touched. In this case, it is reasonable to see small alloy strips or alloy segments in the ribs, that is, it is considered that the function is neither excessive nor redundant, so it is inferred that the design of the grid ribs is reasonable. If the service life of the battery reaches the expected life, and no alloy can be seen inside the grid, it indicates that the rib design of the grid is not enough, and the strength of the rib needs to be increased. If the battery has reached the expected life and the grid corrodes less, there is scope for reducing the weight of the grid.
This design idea of pushing from the back to the front has certain difficulties for the technical personnel without corresponding experiments and experience, but the initial design can be carried out with reference to the relevant content in this section. After all, weight reduction is a relatively secondary link, and meeting the functional requirements of the battery is the first.
With the reduction of the number of grid ribs or the reduction of the cross section, the weight and volume of the grid decrease, the active material increases, and the capacity increases. However, as the grid bars continue to decrease or the section decreases, the capacity increase becomes smaller, to a certain extent, the capacity reaches the highest, and then continues to decrease, the capacity decreases instead. Likewise, both high-current discharge performance and charge acceptance performance will be affected, possibly to a greater extent than capacity. Therefore, the weight reduction of the grid should be based on experiments. Otherwise, sacrificing performance to lose weight is not worth the loss.
The impact of mold making on eye grid production
After the grid is designed, the product must be formed through the mold. The mold is not easy to use, the grid cannot be formed, or the grid is defective. No matter how good the design is, it is useless. Therefore, the design of the grid should be combined with the mold manufacturing and technical level. Although you can design the structure of the ribs and how small the size is, it is meaningless if they cannot be cast. The casting of the grid is similar to other casting products, but the casting of the grid is already small to the limit.
The material of the mold should be uniform. Poor quality blanks may have different hardness, structure and composition in different positions, and such blanks cannot be used. The damaged wool should be heat treated, or stored under wind and rain conditions for more than half a year, which can reduce the stress of the blank and reduce the deformation caused by the change of heat and cold during use. The grid mold should be designed with reasonable exhaust from the structure. If the exhaust is too large, it may lead to lead leakage. If it is too small, the exhaust may not be smooth, resulting in the problem of suffocation and broken bars. The gate and lead channel design should be reasonable, which is also one of the keys to molding.
The production of good molds is very smooth. Foreign advanced battery production companies often look at four machines alone, which is relatively easy, while many domestic companies look at one machine alone, which is more nervous, mainly because of the difference between molds and equipment.