Microvast, Inc. has launched its non-flammable battery technology for lithium-ion batteries. This technology is a breakthrough for the industry, resolving battery safety issues through a multi-level approach from materials to the system level. The technology takes both active and passive protection measures in order to enhance product safety, including improvements to the battery’s electrolyte, separator and protection system.
Although the electric vehicle market experienced a huge upswing last year, especially in China, global automotive giants have not responded to the demand with increased large-scale production and sales. One of the important reasons for this is the unpredictable flammable nature of lithium-ion batteries. The lithium-ion battery has certain risk of random short-circuiting during its production and use, which can cause accidents. Even with a high quality control standard in place (i.e., 2ppm for 18650 cylindrical batteries), in every 100,000 vehicles sold, 1,600 of them would have batteries at risk of bursting into flame.
Research has shown that when thermal runaway occurs in a lithium-ion battery, most of its heat is released by electrolytes, which means electrolytes need to be controlled to ensure safety. However, it is a challenge to develop non-flammable electrolytes with ultra-fast charge capability and long life. Thanks to the tremendous efforts by its research team, Microvast has developed an electrolyte that is non-flammable and can be fully charged within 10-15 minutes and with a cycle life of over 10,000 times.
A high performance separator is also an important protection measure for lithium-ion batteries. A normal lithium-ion battery separator has a low melting point and will usually shrink around 130°C. The resulting short circuit will lead to thermal runaway of the battery. The newly developed separator has a higher melting point compared with commercial ones, which ensures that it does not shrink even at temperatures of up to 300°C. This reduces the possibility of thermal runaway and short circuiting.
In addition to improvements to the electrolyte and separator, the Smart Thermal Liquid (STL) technology is applied to the battery as a protection system, with the battery module immersed in the liquid. As a preferable material of insulation, flame retardation and thermal conductivity, STL can isolate any thermal runaway points from air in the case of short circuiting. Meanwhile, by deploying liquid to reduce the temperature of any thermal runaway point, STL can significantly lower the risk of short circuiting. As a passive protection system, STL also balances temperature differences inside the battery and applies outside circulation to control the battery temperature. Furthermore, the STL can detect any battery leakage that may happen in the battery pack.
The non-combustion electrolyte and the temperature tolerance separator are two active protection methods. Combined with STL intelligent thermal control fluid technology, Microvast has achieved its goals of non-combustion, advanced safety and high performance in a battery system. A demonstration of the combustion of different battery cells was performed at the launch event , which displayed the impressive coordination of non-combustion technology and a normal lithium-ion battery.