STOBA® is the only technology preventing internal short circuits caused by the overheating of Li-ion batteries.
Li-ion batteries are often the most unstable electronic component of devices such as smartphones, laptops, and electric vehicles, as they may overheat under abnormal conditions such as excessive impact and piercing, which has caused many well-documented consumer-device fires and explosions. STOBA® (Self-Terminated Oligomer with Hyper-Branched Architecture), a battery safety material, can reduce the fire hazard of Li-ion batteries by preventing internal short circuits caused by the overheating of Li-ion batteries.
Li-ion battery fires and explosions occur when overheating melts the separator between the anode and cathode, causing an internal short circuit. Under increased temperature, the hyper-branched polymer STOBA® has a unique characteristic: it grows in volume and structural complexity. Added to Li-ion batteries, STOBA® is able to form a protective film providing two lines of defense against fires and explosions: when a battery heats excessively (> 150 ℃) due to external impact or piercing, the end points of the STOBA® polymer’s branched structure react together to form a cross-linking three-dimensional network acting as a physical barrier insulating the anode and cathode, decreasing both electric and ionic conductivity and suppressing thermal runaway. At the same time, STOBA® efficiently scavenges free radicals and suppresses oxygen release to shut down the thermal runaway process. The combination of these two effects virtually eliminates the risk of fire and explosion.
STOBA® has passed mandatory shorting and piercing experiments conducted by battery manufacturers in Japan, Taiwan, and South Korea. The intensive nail penetration and impact tests confirmed STOBA®’s effectiveness in preventing internal shorting and overheating in Li-ion batteries.
STOBA® is currently available in chemical and battery cell production in Japan and Taiwan, and has been granted seven patents in the United States. Based on the concept of STOBA®, ITRI has also developed a novel technology called “ChemSEI-Linker”. This 2017 R&D 100 Award winner can stabilize electrode composition and structure, increasing battery life by up to 100 percent. ChemSEI-Linker has been licensed to TAIWAN STOBA ELECTRODE Co. (TSEC), providing ChemSEI-Linker-embedded electrodes to battery makers and reducing the cost and time of high-safety electrode fabrication.