[Part 4] Comprehensive insights into solid-state battery development


An SSB technology called SCiB is already in production, mainly for 48V hybrid vehicles. The newly designed cathode uses lithium titanium oxide (LTO), which has excellent safety, long life, low temperature performance, fast charging, high input/output power and large effective capacity.

This 20Ah-HP SSB battery is ideal for heavy-duty applications requiring high power input and output, and where heat suppression and continuous operation are required, such as fast charging of commercial vehicles, ferries, and regenerative power systems in rolling stock. The battery is the same size as the current 20Ah product, allowing designers to upgrade to higher input and output power using the same module set.

Although the energy density of the battery is 84 Wh/kg, which is still far behind lithium-ion batteries, its input power is 1.7 times that of the previous generation product (1900 watts) and can reach 50% charge in 10 seconds The output power is 1.6 times that of the previous generation product (1900 watts).

The battery’s resistance is reduced by 40%, resulting in less heat when running at high currents. This is due to the use of a technology called electrospinning to create so-called “skin-coated electrodes”, which cover the surface of the electrode with a nanofiber membrane.

Electrospinning, a technique that creates fibers by applying high pressure to a polymer solution, is suitable for creating the insulating layer of batteries. This technique helps keep ions moving smoothly through electrolyte solutions while maintaining the material’s original properties, such as heat resistance and electrical insulation.

The ultra-thin insulating film can shorten the distance between the positive and negative electrodes and has higher porosity and ion conductivity, thereby reducing internal resistance. Reducing the thickness of the insulating layer also helps increase the capacity of the battery, improving input/output power and capacity.

The reduction in resistance allows the water cooling system to be replaced by forced air cooling, which also simplifies the cooling system and allows for a simpler natural cooling method. Lower resistance also helps reduce overvoltage, allowing the battery to operate over a wider range of states of charge.

Because the 20Ah-HP battery has lower internal resistance, it can effectively suppress heat generation during continuous charging and discharging, so it has a longer life than the current 20Ah battery. Under test conditions, the battery maintained almost 100% capacity after 8,000 charge-discharge cycles, while the current 20Ah battery saw a capacity drop of about 10% under the same conditions, despite having a lifespan of 20,000 cycles. The 20Ah-HP battery performs better than silicon lithium batteries, which have a lifespan of 500 times, and the more rugged lithium iron phosphate (LFP) batteries, which have a lifespan of 2,000 times.