What are the effects of the amount of electrolytic fluid on battery performance

The choice of suitable electrolytic liquid system for different positive and negative electrode materials does not guarantee that the battery has the ready electrochemical performance. It is also necessary to determine the appropriate amount of electrolytic liquid according to the needs of different positive electrode materials.

1. Criteria for the Determination of Electrolytic Liquid Volume Requirements

As the medium of lithium ion transport and charge transfer, the electrolyte should be filled with electrolyte in order to ensure the full application of the active material. The compaction density of each positive electrode material is different, and the demand for electrolytic fluid quantity is different. The general situation is that the demand for electrolytes with high compaction density lithium cobalt acid positive electrode materials is small, and the demand for electrolytes for batteries with low compaction density of ternary and lithium manganese acid positive electrode systems is the largest.

2. Effect of Electrolytic Liquid Quantity on Battery Performance

(1) Effect of Electrolytic Liquid Quantity on Battery Capacity

Figure 1 shows that the electrolyte charging and discharging curve with few drops is abnormal, the charging capacity is much larger than other values, and the discharge capacity is much smaller than other values. The capacity increases with the increase in the amount of electrolytes, and the battery with the best capacity is the diaphragm that just infiltrates. It can be seen that the amount of electrolytic fluid is not enough, the positive film is not enough, and the diaphragm is not penetrated, resulting in large internal resistance and low capacity. The increase in the amount of electrolytes is conducive to making full use of the capacity of active substances. This shows that the battery capacity has a large relationship with the amount of electrolytes, and the battery capacity increases with the increase of electrolytes, but in the end it basically tends to be constant.

(2) Effect of Electrolytic Liquid Quantity on Battery Cycle Performance

From Figure 1, the cycle performance of the battery deteriorated with the increase in capacity of the multiplier. Less electrolytic liquid, lower conductivity, faster internal resistance after the cycle, accelerating the decomposition or volatilization of the battery's local electrolyte, is the deterioration of battery cycle performance gradually accelerated. Too many electrolytes lead to a relative increase in the side reaction of the core, and a large amount of gas is produced, resulting in a decrease in the cycling performance of the core. In addition, excessive electrolytes are also wasted. It can be seen that the amount of electrolytic liquid has a very significant impact on the battery's cycling performance. Too little or too much electrolytes are not conducive to the battery's cycling performance.

(3) Effect of Electrolytic Liquid Quantity on the Safety Performance of Battery

The safety performance of the battery is mainly due to the absence of drum shells and explosions during use. One of the reasons for the battery explosion is that the amount of fluid injected does not meet the process requirements. When the amount of electrolytic liquid is too small, the battery has a large resistance and a lot of heat. The temperature rise causes the electrolyte to quickly decompose and produce gas, and the diaphragm melts, causing the battery to swell and short circuit explosion. When the used electrolytes and negative materials produce too much gas in the side reaction, the electrolyte addition can be reduced by adding an appropriate amount of electrolytic leachate, thereby reducing the problem of excessive gas production and improving battery safety. When the amount of electrolytic liquid is too large, the amount of gas generated during the charging and discharging process is large, the internal pressure of the battery is large, and the shell is broken, causing the electrolyte to leak. When the electrolyte temperature is high, it encounters air and catches fire.

Electrolyte is an indispensable part of lithium-ion batteries, and is a necessary condition for lithium-ion batteries to obtain Gaodianya, high energy density, and high cycle performance. The amount of electrolyte has an important influence on the electrochemical performance and safety performance of the battery. Too much or too little is inappropriate. It is necessary to conduct experiments to determine the amount of electrolytic liquid suitable for positive and negative electrode materials and diaphragm.

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