The impact of low temperature on the performance of lithium-ion battery packs
▲The effect of low temperature on charge and discharge performance
As the temperature drops, the average discharge voltage and discharge capacity of lithium-ion batteries decrease, especially when the temperature is -20℃, the discharge capacity and average discharge voltage of the battery drop more rapidly.
▲The effect of low temperature on circulation function
The battery's capacity decays rapidly at -10℃, with only 59mAh/g remaining after 100 cycles, a capacity reduction of 47.8%. Batteries discharged at low temperatures were then subjected to charge-discharge tests at room temperature to examine their capacity recovery performance. Their capacity recovered to 70.8mAh/g, representing a capacity loss of 68%. This demonstrates that low-temperature cycling significantly impacts battery capacity recovery.
▲The effect of low temperature on safety function
Lithium-ion battery charging is the process by which lithium ions are extracted from the positive electrode, migrate through the electrolyte, and embed into the negative electrode material. Lithium ions aggregate towards the negative electrode, with each six carbon atoms capturing one lithium ion. At low temperatures, chemical reactivity decreases, and lithium ion migration slows down. Lithium ions on the negative electrode surface are reduced to metallic lithium before they can embed into the negative electrode, precipitating as lithium dendrites. This can easily puncture the separator, causing an internal short circuit and damaging the battery, leading to safety incidents.
It's best not to charge lithium-ion battery packs in winter. Due to the low temperature, the lithium ions nested on the negative electrode will crystallize, directly piercing the separator. Under normal conditions, this can cause a micro-short circuit, affecting lifespan and performance, and in severe cases, even leading to an explosion. Therefore, some people report that lithium-ion batteries cannot be charged in winter; this is because some batteries with built-in battery protection systems are protected by the product.
