I. The typical temperature range for soft-pack lithium batteries
The operating temperature of soft-pack lithium batteries is similar to the comfortable zone for humans. The standard models can maintain stable discharge within the range of -20℃ to 60℃. When the ambient temperature exceeds 60℃, the activity of the electrolyte will significantly increase, and the positive and negative electrode materials may undergo side reactions. Some specially designed industrial pouch cells, through improvements such as ceramic separators, can withstand temperatures of around 100℃ for a short period.
II. Three Challenges Caused by High Temperature Environments
Cycle life degradation: Under continuous high temperatures, the aging speed of the battery increases by approximately 1 times for every 10℃ increase
Internal resistance fluctuation: After the temperature exceeds 70℃, some electrolytes decompose, causing the internal resistance to increase by more than 15%
Structural risks: The aluminum-plastic encapsulation film may separate at temperatures above 120℃, affecting the airtightness
III. Innovative Directions for Improving Heat Resistance
Researchers are breaking through the temperature limit through three paths:
Solid-state electrolytes: Replace organic electrolytes with inorganic materials, allowing the temperature tolerance to increase to 150℃
Self-healing separators: Automatically close micro-pores when the temperature is abnormal, blocking the chain reaction of thermal runaway
Phase change material coatings: Absorb excess heat to maintain the internal temperature balance of the battery cell
