Nickel-cadmium accumulator

Abstract

The nickel-cadmiunm accumulator includes negative pole of cadmium oxide and positive pole of nickel hydroxide. The negative pole of cadmium oxide is adhered one and dry powder for the negative pole consists of active cadmium oxide, conducting agent and other additives, and the conducting agent is copper hydroxide in the added amount of 1-5 % of the dry powder weight. The positive pole has spherical granular nickel hydroxide as its active matter. Using copper hydroxide as the conductive additive for the cadmium negative pole can improve the performance of Ni-Cd accumulator, lower its internal resistance, reduce capacity attenuation and raise great current discharge performance.

Description

technical field [0001] The invention relates to a nickel-cadmium storage battery, in particular to a conductive agent used in a cadmium negative electrode. Background technique [0002] Nickel-cadmium batteries have been widely used because of their stable performance, low price and adaptability to various working conditions. Nickel-cadmium batteries are generally designed to limit the positive electrode, that is, the capacity of the negative electrode is excessive. After the positive electrode is fully charged, the potential of the positive electrode rises, and the oxygen evolution reaction occurs at the positive electrode; however, due to the excess of the negative electrode, the reaction that occurs at this time is still the charging reaction of the active material. , if the oxygen generated by the positive electrode can reach the negative electrode through the diaphragm, and the negative electrode has a strong ability to absorb oxygen, then oxygen recombination reaction ...

AI Technical Summary

Problems solved by technology

[0003] However, in fact, for cadmium negative electrodes, especially bonded (or paste) cadmium negative electrodes, there are often the following problems: 1) poor oxygen recombination ability; 2) coarse grains of active materials; 3) cadmium dendrites ; 4) hydrogen evolution

The inventor's research found that when carbon powder is added to the active material, due to the large surface energy of the carbon powder, it is easy to self-aggregate so that it cannot be uniformly dispersed in the active material slurry, which affects the uniformity of the conductive network: and the carbon powder The conductivity of the cadmium powder itself is still not very good, and it cannot have a good affinity with the active material, so the conductivity of the cadmium negative electrode is still poor; when nickel powder is added to the negative electrode, a good conductive effect can be achieved, and the nickel powder It can play a certain catalytic effect on the recombination of oxygen in the cadmium negative electrode, so it can significantly improve the oxygen elimination ability of the negative electrode, but the price of nickel powder as a conductive additive is relatively expensive, and at the same time, because the precipitation overpotential of hydrogen on nickel is low, Plate hydrogen reaction is prone to occur during charging: when carbon fiber is used, due to its high price, it is not suitable for manufacturers when the profit of the battery itself is already very small.

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