Polymer lithium batteries are widely used in modern electronic equipment and new energy fields, but low-temperature environments will have a significant impact on their performance.
Under low temperature conditions, Polymer lithium batteries face many challenges. First, the electrochemical reaction rate inside the battery is greatly reduced. Low temperature increases the viscosity of the electrolyte and slows down the ion conduction rate, causing the battery resistance to significantly increase. For example, at minus 20 degrees Celsius, the internal resistance of the battery may increase several times compared to normal temperature. This directly causes the voltage drop of the battery to increase during the discharge process, and the power that can be output is greatly reduced, resulting in a sharp decline in the battery life of the device. Secondly, low temperature may also trigger the growth of lithium dendrites. During the charging process, lithium ions are unevenly deposited on the surface of the negative electrode, forming sharp lithium dendrites. This will not only consume the active lithium in the battery and reduce the battery capacity, but may also pierce the separator, causing an internal short circuit in the battery and causing serious safety hazards. question.
To improve the low-temperature performance of Polymer lithium batteries, various approaches are being explored. In terms of materials, the development of new low-temperature electrolytes is one of the key measures. By adding special organic solvents or electrolyte salts, the freezing point of the electrolyte is lowered and the migration rate of ions at low temperatures is increased. For example, the use of some fluorocarbonate solvents can effectively improve the performance of electrolytes at low temperatures. At the same time, modification of electrode materials is also crucial. The use of nanostructured electrode materials can increase the contact area between the electrode and the electrolyte, shorten the diffusion path of lithium ions, and improve the electrochemical reaction activity. For example, nano-silicon-based negative electrode materials show better lithium ion insertion and extraction performance at low temperatures.
The structural design of the battery can also help improve low-temperature performance. Optimize the pole piece structure of the battery, such as adjusting the thickness, porosity and other parameters of the pole piece, so that lithium ions can shuttle between the electrode and electrolyte more smoothly during the charge and discharge process. Additionally, employing a good thermal management system is integral to improving low-temperature performance. A heating element is integrated into the battery module. When the temperature is too low, the heating function is automatically activated to raise the battery temperature to a suitable working range, ensuring that the battery can charge and discharge normally and maintain stable performance.
Although the low-temperature performance of Polymer lithium batteries is challenging, it is expected to be gradually improved through comprehensive measures such as material innovation, structural optimization, and thermal management, thereby further expanding the use of Polymer lithium batteries in cold areas and applications that require low-temperature performance. The scope of use in special application scenarios promotes the technological development and application popularization in related fields.
