With the popularization of electric vehicles and portable electronic products , lithium battery has become the mainstream battery type. However, lithium batteries will reduce their capacity and performance in low temperature environment, which brings challenges to their use in extreme weather conditions. So, why is lithium battery "afraid" of low temperature? This is a complex problem involving materials science, electrochemical and thermodynamic fields. This article will explain the problems of lithium battery in low temperature environment from the aspects of working principle, material characteristics and thermal characteristics of lithium battery.

Working Principle of lithium battery

lithium batteries realize charge and discharge through the reciprocating migration of lithium ions between positive and negative electrodes. During charging, lithium ions migrate from the positive electrode (usually oxide) to the negative electrode (usually graphite), while during discharging, the opposite is true. This ion migration is achieved by ion conduction in the electrolyte. In low temperature environment, the ionic conductivity of electrolyte will decrease, which makes it difficult for lithium ions to be transmitted between electrodes, thus affecting the performance of battery.

Influence of material properties

in the low temperature environment, the material characteristics inside the lithium battery will also change. Firstly, the conductivity and ion conductivity of the electrode material will decrease, which will affect the charge-discharge rate and capacity of the battery. Secondly, the solidification temperature of electrolyte will decrease, resulting in the solidification of electrolyte, thus hindering the conduction of lithium ions. In addition, at extremely low temperature, the liquid electrolyte in the battery will even freeze, further affecting the normal operation of the battery.

Influence of thermal properties

in low temperature environment, the thermal characteristics of lithium batteries will also change. The performance and capacity of lithium battery will change with the change of temperature, usually at low temperature, the capacity and output power of the battery will decrease. In addition, under the low temperature environment, the chemical reaction speed inside the battery will slow down, thus affecting the charge-discharge rate and cycle life of the battery.

Solve problems in low temperature environment

in order to solve the problem of lithium battery in low temperature environment, scientists and engineers have done a lot of research and innovation. Some solutions include: optimizing the material formula of the battery, improving the design of electrode and electrolyte, improving the thermal management performance of the battery, etc. For example, the development of electrolyte suitable for low temperature and electrode materials with special additives can improve the performance of the battery in low temperature environment. In addition, reasonable design of heating system and thermal management system can also improve the performance and cycle life of batteries in low temperature environment.

The problem of low capacity and indurability of lithium batteries in low temperature environment is a complex scientific problem, involving many fields such as material science, electrochemical and thermodynamics. By optimizing the material and structure design of the battery and improving the thermal management performance of the battery, we believe that this problem can be solved in the future, so that the lithium battery can play a better performance in a wider range of climate conditions.