Safety comparison of lithium nickel cobalt manganese oxide, lithium iron phosphate, lithium cobalt oxide and lithium manganate

Nickel cobalt cobalt manganate (ternary) battery

In the actual available theoretical specific energy, it can greatly improve the high-capacity effect compared with the lithium cobalt oxide battery. However, from the material point of view, the ternary battery uses lithium nickel cobalt manganese oxide and organic The electrolyte has not fundamentally solved the safety problem. If the battery is short-circuited, it will generate excessive current, which will cause safety hazards.

lithium iron phosphate battery

The theoretical capacity is 170 mAh/g and the actual reachable capacity of the material is 160 mAh/g. In terms of safety, lithium iron phosphate is thermally stable and high, and the electrolyte has low oxidation ability, so the safety is high; but the defect is low conductivity, excessive volume, and a large amount of electrolyte and the battery has poor consistency due to large capacity.

Lithium cobaltate battery

The biggest feature in preparation is that after fully charged, a large amount of lithium ions remain in the positive electrode, that is, no more lithium ions attached to the positive electrode are accommodated on the negative electrode, but in the overcharged state, Excess lithium ions on the positive electrode will still swim toward the negative electrode, because metal lithium cannot be completely accommodated and turned back on the negative electrode. Since metallic lithium is a dendritic crystal, it is called dendrite. Once the dendrites are formed, they will be given. Piercing the diaphragm provides an opportunity for the diaphragm to pierce to create an internal short circuit. Since the main component of the electrolyte is carbonate, the flash point and boiling point are low, and it will burn or even explode at a higher temperature. Controlling the formation of lithium dendrites is relatively easy on small-capacity lithium batteries, so lithium cobalt oxide batteries are currently limited to small-capacity batteries such as portable electronic devices, and cannot be used for power batteries.

Lithium manganate battery

The material of the lithium manganate battery has a certain point, which can ensure that the lithium ion of the positive electrode can be completely embedded in the carbon hole of the negative electrode under the full power state, instead of having a certain residual in the positive electrode like lithium cobalt oxide, which is fundamentally The occurrence of dendrites is avoided. In theory, in fact, if a lithium manganate battery encounters a strong external force or cuts corners during the preparation process, it may cause the lithium ions to rapidly move during the charge and discharge cycle. Dendrites are formed in the case where the negative electrode does not have complete lithium ion reception. Avoiding this consequence is guaranteed by testing the battery at the factory. In short, the qualified lithium manganese oxide battery generally does not cause a safety accident. The stable structure of lithium manganate makes its oxidation performance much lower than that of lithium cobaltate. Even if it is externally short-circuited, it can basically avoid the combustion and explosion caused by the precipitation of metallic lithium.

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