Lithium-ion batteries have become the dominant power source for portable electronic devices and electric vehicles due to their high energy density and long cycle life. However, these batteries also pose safety hazards, including short circuits, overcharging, thermal runaway, and combustion. These issues can lead to battery explosions or fires, causing severe safety accidents.
To enhance the safety performance of lithium-ion batteries, scientists are continuously exploring new technologies and approaches. This article delves into the latest advancements in lithium-ion battery safety technology.
Internal Short Circuit Protection
- Ceramic Separator: Ceramic separators offer exceptional thermal and mechanical stability, effectively preventing short circuits caused by lithium dendrite piercing.
- Negative Electrode Heat Resistance Layer: Coating the negative electrode surface with a heat-resistant material enhances its stability and reduces the risk of short circuits.
Overcharging Protection
- Additive Redox Couple: Introducing an additive redox couple into the electrolyte controls the battery's charging voltage, preventing overcharging that could lead to battery explosions.
- Voltage-Sensitive Separator: Incorporating voltage-sensitive materials into the separator allows it to become conductive when the battery voltage exceeds a safe limit, cutting off the charging current and preventing overcharging.
Thermal Runaway Prevention
- PTC Electrode: PTC electrodes feature a positive temperature coefficient. As the battery temperature rises, their resistance increases sharply, cutting off the current and preventing thermal runaway.
- Thermally Closed Electrodes: Coating the electrode surface with a heat-fusible material causes it to melt upon temperature increase, blocking ion transport and potentially terminating the battery reaction.
- Thermally Cured Electrolyte: Adding heat-polymerizable monomers to the electrolyte triggers polymerization at high temperatures, hardening the electrolyte and shutting off ion migration, ending the battery operation.
Non-flammable Electrolyte
- Phosphate Esters: Phosphate esters are flame retardant compounds that effectively prevent battery combustion.
Future Prospects
Despite significant progress in lithium-ion battery safety technology, several challenges remain:
- Further Enhancing Battery Safety: Developing even safer lithium-ion batteries is crucial.
- Reducing Battery Cost: Cost-effective safety solutions are essential for widespread adoption.
- Extending Battery Life: Balancing safety with extended battery life is a key objective.
Researchers continue to explore new technologies and methods to create safer, more reliable, and cost-effective lithium-ion batteries.