Causes of Thermal Runaway in Lithium Ion Batteries

Thermal runaway in lithium ion batteries is a dangerous chain reaction where the battery's internal temperature rises uncontrollably, potentially leading to fire or explosion. Thermal runaway is typically triggered by one or more of the following factors:

1. Internal Short Circuit
Manufacturing defects, such as impurities, damaged separators, or dendrite growth. Localized heating within the cell, which can ignite internal components.

2. External Short Circuit
Damage to the battery casing or contact with conductive materials.
A large current flow leads to rapid heating and potential ignition.

3. Overcharging
Charging the battery beyond its voltage limit (typically beyond 4.2V per cell). Decomposition of the electrolyte and release of oxygen, triggering exothermic reactions.

4. Overdischarging
Discharging the battery below its safe voltage level. it can cause copper dissolution and internal shorts during future charging.

5. High Temperatures
Hot environments, poor ventilation, or inadequate thermal management. Accelerates chemical reactions, potentially triggering runaway.

6. Mechanical Damage
Crushing, puncturing, or dropping the battery. Damaged internal structure may lead to short circuits or chemical leaks.

✅ CTS Battery How to Effectively Prevent Thermal Runaway

1. High-Quality Battery Design & Manufacturing
Use durable, high-purity materials.
Employ robust separators to prevent internal short circuits.
Use thermally stable electrolytes and electrodes.

2. Battery Management System (BMS)
Constantly monitors voltage, current, and temperature.
Provides protections such as Overcharge protection/Overdischarge protection/Overcurrent and short-circuit protection/Thermal cutoff.

3. Thermal Management
Use cooling systems (air or liquid) to maintain safe operating temperatures. Design battery packs with ventilation and heat dissipation structures.

4. Safe Charging Practices
Use certified chargers that match the battery specifications. Avoid fast charging in hot environments. Do not charge damaged or swollen batteries.

5. Avoid Mechanical Stress
Protect batteries from impacts, punctures, and crushing forces.
Use rugged enclosures for battery packs in harsh environments.

6. Environmental Controls
Store and operate batteries within recommended temperature ranges. Avoid exposure to direct sunlight, fire, or freezing conditions.

7. Regular Inspection and Maintenance
Check for bulging, corrosion, or unusual behavior. Replace aging or damaged batteries promptly.