Blocking Cathode-Anode Contact with Ceramic Coated Separator... Critical to Prevent Battery Fires

LG Energy Solution and SK On Unveil Successive Technologies
Triple and Quadruple Fire Safety Devices
"Overcharge Prevention Must Be Included in Slow Chargers"

As safety concerns regarding electric vehicles and batteries grow, domestic battery companies are advancing the development of technologies that can control thermal runaway phenomena along with triple and quadruple safety devices to prevent fires.

According to the industry on the 12th, recently, the Samsung SDI research team, together with Professor Lim Jong-woo's chemistry team at Seoul National University and Professor Kim Won-bae's chemical engineering team at POSTECH, released research results elucidating the mechanism of 'battery thermal runaway.' Thermal runaway refers to a phenomenon where, once a fire occurs in a battery, temperatures exceed 700 degrees Celsius within seconds. In the early stages of a fire, ethylene gas generated from the graphite anode moves to the cathode, producing oxygen, which in turn generates ethylene gas again at the anode, releasing heat. If this process occurs rapidly and in a chain reaction, a sudden temperature rise happens. The research team succeeded in suppressing thermal runaway by applying an alumina coating to the graphite anode to block the thermal runaway reaction.

The separator, a crucial material for preventing battery fires, is also enhancing safety. The separator serves as a pathway for electrons while preventing direct contact between the cathode and anode. Recently, domestic manufacturers have been expanding the application of ceramic-coated separators instead of wet separators to improve electric vehicle safety.

LG Energy Solution developed a 'Safety Reinforced Separator (SRS)' coated with ceramic particles. The ceramic particles help prevent the polymer separator from shrinking. SK On introduced a technology that minimizes stress on battery cells and blocks the possibility of cathode and anode contact by stacking separators in a zigzag pattern called the 'Z-folding' method, thereby reducing the risk of fire.

Before the "Lithium Battery Fire Dedicated Extinguishing Device Demonstration" held last June at the Guard K Daegu Factory in Seo-gu, Daegu, a cylindrical lithium battery was shown undergoing thermal runaway. [Image source=Yonhap News]

Not only battery cells but also Battery Management Systems (BMS) are evolving. BMS monitors voltage, current, temperature, and other parameters in real time to maintain the battery in optimal condition. When voltage differences occur between cells, it adjusts them uniformly to improve battery energy efficiency and extend lifespan. It also plays a role in preventing overcharging and over-discharging during the battery's charging and discharging processes. Professor Lee Ho-geun of Daeduk College's Automotive Department stated, "BMS needs to develop in a way that it can protect the vehicle by monitoring battery cells even when the car is off, sending warnings to the driver if there is a fire risk, and automatically notifying nearby fire facilities." Additionally, there is a trend to apply 'flame-retardant plastics' to battery packs to prevent fire spread to other battery cells even if thermal runaway occurs.

Recently, chargers identified as causes of battery fires are also pointed out as needing changes for safety. While fast chargers stop charging at about 80%, slow chargers continue charging up to 100% unless the vehicle owner manually stops it, increasing fire risk. Professor Kim Pil-soo of Daelim University said, "Most domestic electric vehicle fires are due to overcharging or battery cell defects," and emphasized, "Overcharge prevention devices should be mandated for slow chargers."

This content was produced with the assistance of AI translation services.