Positive electrode plate, negative electrode plate and high-rate rapid-charge lithium ion battery

Abstract

The invention relates to a positive electrode plate for a high-rate rapid-charge lithium ion battery, a negative electrode plate and the high-rate rapid-charge lithium ion battery. The positive (negative) electrode plate is characterized by comprising a positive (negative) current collector, a positive (negative) active substance coating layer and an ion conduction coating layer, wherein the positive (negative) current collector is provided with two opposite surfaces, the positive (negative) active substance coating layer is coated on at least one surface of the positive (negative) current collector, and the ion conduction coating layer is coated on the positive (negative) active substance coating layer. The high-rate rapid-charge lithium ion battery comprising the positive electrode plateand the negative electrode plate is low in internal resistance, small in charge-discharge temperature rising, high in initial charge-discharge efficiency and good in cycle property and safety.

Description

technical field [0001] The invention relates to a lithium-ion battery, in particular to a positive pole piece, a negative pole piece and a corresponding lithium-ion battery of a high-rate fast-charge lithium-ion battery. Background technique [0002] At present, high-rate lithium-ion batteries have been extensively researched and applied, and their characteristic is that they can be discharged with a large current or can be charged quickly, so they are widely used in power batteries and other fields. [0003] In a lithium-ion battery, the active material coating on the electrode sheet is in direct contact with the electrolyte. During the first charge and discharge of the battery, a layer with a thickness of about 100-120nm passivation layer, that is, solid electrolyte interface film (solid electrolyte interface), referred to as SEI film. This layer of SEI film can avoid the direct contact between the electrolyte and the negative electrode, reduce the decomposition of the el...

AI Technical Summary

Problems solved by technology

[0004] In addition, the separator between the positive pole piece and the negative pole piece of the lithium-ion battery is mainly made of microporous membrane made of polypropylene, polyethylene or their copolymers, which is easy to shrink at high temperature, which may cause positive and negative Negative electrodes are in direct contact to form an internal short circuit; at the same time, during fast charging, if lithium ions cannot be quickly inserted into the negative electrode, it will also cause lithium precipitation. Severe lithium precipitation will lead to the formation of lithium dendrites, which may pierce the polymer microporous separator , causing an internal short circuit

A short circuit inside the battery will cause the battery to overheat abnormally, causing safety problems

[0005] Lithium separation at the negative electrode also consumes lithium ions in the battery, causing the battery capacity to rapidly decay and the battery cycle performance to deteriorate

[0006] Especially when the lithium-ion battery is fast charging or discharging at a high rate, due to the large charge and discharge current, the heat generated by the internal resistance of the battery will also increase, and the higher the internal resistance, the greater the heat generated. If it is large and does not have effective heat dissipation, it is likely to make the battery temperature too high, which may lead to thermal runaway and more serious safety problems such as burning or even explosion.

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