Lead-Acid Battery Thermal Runaway: Causes, Prevention & Safety

 

Understanding Lead-Acid Battery Thermal Runaway

 

Battery thermal runaway is a phenomenon where the internal temperature of a battery rises uncontrollably, accompanied by an abnormal increase in current. In lead-acid batteries (including SLA battery and VRLA battery), thermal runaway usually occurs because the heat generated during charging or discharging cannot be effectively dissipated, leading to a continuous rise in the battery's internal temperature, creating a vicious cycle.

• Causes: Overcharging, high ambient temperatures, internal short circuits, and uneven electrolyte distribution can all lead to thermal runaway.
• Symptoms: The battery casing becomes hot, swells, or even deforms, electrolyte leakage occurs, battery performance deteriorates rapidly, and an unusual odor may be emitted.
• Consequences: Severe thermal runaway can lead to battery failure and even safety hazards.

 

 Factors Leading to Lead-Acid Battery Thermal Runaway

 

• Overcharging: Prolonged or excessively high voltage charging can generate excessive heat inside the battery.
• High Ambient Temperatures: High temperatures accelerate internal chemical reactions within the battery, increasing the risk of thermal runaway.
• Internal Short Circuits: Damage to the internal separator or the presence of impurities can cause short circuits, generating a large amount of heat.
• Uneven Electrolyte Distribution: Uneven distribution of the electrolyte can lead to significant temperature differences within the battery.
• Battery Aging: As the battery ages, its internal resistance increases, which also increases heat generation.

 

Can Lead-Acid Battery Thermal Runaway Cause Fires? 

 

Compared to lithium batteries, lead-acid batteries have a lower probability of experiencing severe thermal runaway and causing fires. This is because the electrolyte in lead-acid batteries is mainly a water-based sulfuric acid solution, which is not easily flammable. Although thermal runaway can cause the battery casing to deform, smoke, or even eject acid, it usually does not lead to violent combustion or explosion like lithium batteries. Due to this characteristic, along with its relatively mature and stable technology, VRLA battery and SLA battery are still the more common choices in marine battery applications, especially in scenarios with high safety requirements, such as ships. When considering runaway vs power in marine applications, the risk of runaway is a crucial factor.

 

How to Prevent Lead-Acid Battery Thermal Runaway

 

• Proper Charging: Use a compatible charger and avoid overcharging.
• Control Ambient Temperature: Avoid exposing the battery to high temperatures.
• Regular Inspection: Regularly inspect the battery's appearance, connections, and electrolyte level (for non-sealed batteries).
• Avoid Severe Vibrations: Severe vibrations can damage the internal structure of the battery.
• Use High-Quality Batteries: Choose reliable brands and products, such as BB Marine batteries from HZH Marine.

 

Conclusion

 

While lead-acid battery thermal runaway poses certain risks, it can be effectively prevented through proper operation and maintenance. Compared to other types of batteries, lead-acid batteries still have advantages in terms of safety and cost, especially in marine battery applications. BB Marine batteries (battery acid battery) from HZH Marine are manufactured with high-quality materials and advanced processes, offering excellent reliability and durability, making them a trustworthy choice. Thermal runaway battery is a concern, but choosing the right battery and taking preventive measures can minimize the risk.