Introduction

Lithium batteries may produce gas during use. If too much gas is produced, it not only affects battery performance but may also cause safety issues. Therefore, it is of great practical significance to conduct in-depth research on the causes and impacts of gas production in lithium batteries, and to take effective preventive and improvement measures.

The reason for excessive gas production in lithium batteries

1. When the battery is overcharged, lithium ions are excessively embedded in the negative electrode, which may lead to electrolyte decomposition and gas production. Overcharging can increase the internal pressure of the battery, affecting its stability and safety.

2. Excessive deep discharge can damage the structure of the negative electrode material, resulting in the generation of gas. Overdischarging can reduce the capacity and lifespan of the battery, while also increasing safety risks.

3. High temperature environments can accelerate internal chemical reactions in batteries, leading to electrolyte decomposition and gas generation. High temperatures can also affect the performance and lifespan of batteries, and may even cause thermal runaway.

4. Internal short circuits in batteries can cause high currents, resulting in the generation of a large amount of heat and gas. Internal short circuits may be caused by manufacturing defects, impurities, or mechanical damage.

5.  As the battery ages, the internal materials of the battery may gradually decompose and produce gases. Aging of batteries can reduce their performance and lifespan, and increase safety hazards.

6.  Defects in the manufacturing process of batteries, such as impurities, micro short circuits, etc., may also lead to gas generation. Manufacturing defects can affect the quality and reliability of batteries.

The impact of excessive gas production in lithium batteries

1. It will affect battery performance. Excessive gas production can lead to an increase in internal pressure of the battery, which may damage the sealing structure of the battery and cause electrolyte leakage, thereby reducing the capacity and cycle life of the battery. In addition, the generation of gas can also affect the internal resistance and charge discharge efficiency of the battery.

2. If the internal pressure of the battery is too high, it may cause the safety valve to open, and even lead to safety accidents such as explosions and fires. Meanwhile, harmful substances in gases may also pose a threat to human health and the environment. 

Preventive and Improvement Measures

1. Optimize Charging Strategy   

① Using an intelligent charger can monitor the battery status and prevent overcharging. The intelligent charger can automatically adjust the charging current and voltage based on parameters such as battery voltage, current, and temperature, ensuring that the battery is charged within a safe range.

② When the battery is close to being fully charged, reduce the charging current. Trickle charging can reduce the decomposition of electrolyte and lower the risk of gas production.

2. Set the minimum discharge voltage threshold for the battery to avoid excessive discharge. 

In the battery management system, an over discharge protection function can be set, which automatically cuts off the circuit when the battery voltage is below the set threshold to prevent the battery from continuing to discharge.

3. Temperature control

① In the design and use of batteries, heat dissipation measures should be considered, such as using heat sinks, fans, etc., to effectively reduce the temperature of the battery, minimize the decomposition of electrolyte, and reduce gas generation.

② High temperature environments can accelerate battery aging and gas production, so it is advisable to avoid using and storing batteries in high-temperature environments as much as possible.

4. Optimization of Battery Management System

① Adopting advanced Battery Management System (BMS) to monitor battery status and adjust working conditions in a timely manner. BMS can monitor real-time parameters such as voltage, current, temperature, and internal resistance of the battery, adjust the battery's charging and discharging strategies based on these parameters, and ensure that the battery operates within a safe range.

② BMS should have overcharge, overdischarge, and overheat protection functions. When there is an abnormal situation with the battery, BMS can promptly cut off the circuit to protect the safety of the battery.

5. Regular maintenance and inspection

① Through regular inspections, abnormal conditions of the battery can be detected in a timely manner and corresponding measures can be taken to deal with them.

② If abnormal conditions such as excessive gas production, decreased capacity, and increased internal resistance are found in the battery, timely maintenance or replacement should be carried out to ensure the safety and performance of the battery.

6. Choose electrolytes and electrode materials with good electrochemical stability. High quality electrolyte and electrode materials can improve the performance and safety of batteries, and reduce the risk of gas production.

7. When designing batteries for safety, pressure relief devices such as safety valves should be considered to prevent excessive internal pressure.

Conclusion

The generation of gas during the use of lithium batteries is a complex problem, which involves multiple factors such as overcharging, overdischarging, high temperature, internal short circuit, battery aging, and manufacturing defects. Excessive gas production can have a serious impact on battery performance and safety. 

In order to effectively reduce gas production in lithium batteries, extend battery life, and ensure safe use, a series of preventive and improvement measures need to be taken, including optimizing charging strategies, preventing over discharge, temperature control, optimizing battery management systems, improving manufacturing quality, regular maintenance and inspection, using high-quality materials, and safety design.