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Factors affecting fast charging of lithium batteries(II)
- Jul 25, 2018 -

For the lithium battery, if the power performance is to be improved, it is necessary to work hard in all parts of the battery, mainly including positive pole, negative electrode, electrolyte, diaphragm and structure design.

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1. Diaphragm

For power batteries, high current operation provides higher requirements for safety and longevity. Diaphragm coating technology is inseparable. Ceramic coated membranes are rapidly being pushed away due to their high safety and the ability to consume impurities in the electrolyte. Especially for the safety of ternary batteries, the safety effect is particularly remarkable.

The main system currently used in ceramic diaphragms is to coat alumina particles on the surface of conventional diaphragms. A relatively novel approach is to coat solid electrolyte fibers on the membrane. Such membranes have lower internal resistance and mechanical support for the membrane. Excellent, and it has a lower tendency to block the diaphragm hole during service. After the coating, the separator has good stability, and even if the temperature is relatively high, it is not easy to shrink and deform to cause a short circuit.

2. Electrolyte

The electrolyte has a great influence on the performance of a fast-charged lithium ion battery. To ensure the stability and safety of the battery under fast charge and high current, the electrolyte should meet the following characteristics: 1) Can not be decomposed. 2) The conductivity is high. 3) Is inert to the positive and negative materials, can not React or dissolve.

If these requirements are to be met, the key is to use additives and functional electrolytes. For example, the safety of ternary fast-charged batteries is greatly affected by it. It is necessary to add various anti-high temperature, flame-retardant and anti-overcharged additives to protect them to a certain extent. The problem of the old lithium titanate battery, the high temperature flatulence, also depends on the high temperature functional electrolyte.

3. Battery structure design

A typical optimization strategy is the stacked VS winding type. The electrodes of the laminated battery are equivalent to a parallel relationship, and the winding type is equivalent to a series connection. Therefore, the internal resistance of the former is much smaller, and it is more suitable for the power type. occasion.

In addition, you can work hard on the number of poles to solve internal resistance and heat dissipation problems. In addition, the use of high-conductivity electrode materials, the use of more conductive agents, and the coating of thinner electrodes are also strategies that can be considered.

In a word, the factors that affect the battery internal charge movement and the electrode hole rate will affect the fast charging capability of the lithium battery.