Rechargeable batteries, also known as secondary batteries, undergo wear and tear over time, much like any other frequently used item. To maximize the battery's lifespan and performance, correct usage and proper maintenance are essential. One important factor to keep in mind is thermal runaway, a phenomenon where the battery’s temperature increases uncontrollably, potentially leading to damage, failure, or even fire. Avoiding exposure to extreme heat, preventing overcharging, and using chargers specifically designed for the battery type can help mitigate the risk of thermal runaway. Proper handling ensures that your rechargeable battery performs efficiently and safely over time.
Thermal Runaway
Thermal runaway is one of the most common challenges when using rechargeable batteries. It starts when the heat generated inside the battery becomes greater than the amount of heat that is released to its surroundings. This increase in temperature then leads to an increase in the rate of a chemical reaction, which in turn produces more heat. This cycle can quickly escalate, leading to a rapid rise in temperature and the release of large amounts of energy. In some cases, thermal runaway can cause a battery to catch fire or worse, explode.
There are several factors that can contribute to thermal runaway in batteries such as overcharging, overheating, physical damage (e.g. puncture or impact), manufacturing defect, and improper use.
The good thing is that there are a number of ways that we can do to prevent this event from happening like proper charging based on the instructions manual provided by the manufacturer. Another one is to keep batteries away from heat sources and direct sunlight to avoid overheating. In addition, inspect batteries regularly for signs of physical damage like dents and cracks. And finally, use the batteries in their intended applications and not in those that exceed their rated capacity.
Detecting and Extinguishing Thermal Runaway
Detecting runaway thermal can be quite tricky but there are early signs that you can watch out for that may indicate that a battery is experiencing thermal runaway, including:
- Increased temperature: The temperature of the battery may increase significantly.
- Excessive gassing: The battery may emit gas, such as hydrogen or oxygen.
- Deformation: The battery may swell or deform.
- Smoke or flames: The battery may smoke or catch fire.
If a battery is experiencing thermal runaway and has caught fire, it is important to take immediate action to extinguish the flame. The best way to extinguish a battery fire depends on the type of battery and the severity of the fire. However, in general, it is crucial to use a fire extinguisher that is appropriate for the type of battery. For example, a water extinguisher should not be used to extinguish a fire involving a lithium-ion battery, as this could cause the battery to explode.
Minimize the Safety Risks of Thermal Runaway
The safety risks of thermal runaway can be mitigated by taking steps to prevent thermal runaway from occurring, such as using batteries properly and inspecting them regularly for signs of damage. In addition, it is important to have a plan in place to deal with a battery fire, such as having a fire extinguisher that is appropriate for the type of battery.
The Role of Battery Management System (BMS) in Thermal Runaway
A battery management system (BMS) is a system that monitors and controls the performance of a battery. It can be used to prevent thermal runaway from happening by monitoring the temperature, voltage, and current of a battery. If the BMS detects any abnormalities, it can take steps to prevent thermal runaway, such as:
- Discharging the battery: If the battery's temperature gets too high, the BMS can discharge the battery to help cool it down.
- Stopping charging: If the battery is overcharged, the BMS can stop charging to prevent the battery from overheating.
Disabling cells: If a cell in the battery starts to overheat, the BMS can disable that cell to prevent the heat from spreading to other cells.
One very good example of this is the latest product of Nature’s Generator. As one of the trusted companies in the solar generator industry in the country, Nature’s Generator has upped their game and created Eco-Intelligent Li, the safest Lithium Iron Phosphate (LiFePO4) battery on the planet. What makes this battery amazing is that it makes use of a smart Battery Management System (BMS) that does the things that were mentioned above including thermal runaway prevention and at the same time, it allows the simultaneous use of old lithium and lead acid batteries along with the Eco-Intelligent Li battery itself.
How BMS Can Prevent Thermal Runaway
- Temperature monitoring: The BMS constantly monitors the temperature of the battery and takes action if it gets too high. This can be done by using sensors to measure the temperature of the battery cells or by using a heatsink to dissipate heat.
- Current monitoring: In addition, the BMS also monitors the current flowing through the battery and acts right away if it gets too high. Using sensors to measure the current flowing through the battery cells or by using a fuse to protect the battery from overcurrent will do the trick.
- Voltage monitoring: Moreover, the BMS also monitors the voltage of the battery and takes the appropriate action if it gets too high or too low. This can be achieved by using sensors to measure the voltage of the battery cells or by using a regulator to keep the voltage within a safe range.
- Cell balancing: The BMS can also balance the cells in the battery to prevent one cell from becoming too hot or too cold. This can be done by equalizing the charge of the cells or by using a heating or cooling system to keep the temperature of the cells within a safe range.
By taking these steps, a BMS can help prevent thermal runaway. In addition to that, a BMS can also help extend the life of a battery by preventing overcharging, over-discharging, and other factors that can damage the battery.
Conclusion
Thermal runaway is a serious safety hazard that can occur in batteries. It is important to understand the causes of thermal runaway and to take steps to prevent it from occurring. In the event of a battery fire, it is important to take immediate action to extinguish the fire.
A reliable battery management system (BMS) can be used to detect the overall health of a battery and prevent battery problems including thermal runaway from happening.
* We want to give credit where credit is due. Professional writer, Ann Matthew, contributed research and content to this blog titled: Thermal Runaway Thank you, Ann, for your contributions!
