Inpow Battery unveils industry-first 587 Ah semi-solid-state storage cell in massive safety boost

Inpow Battery and the National Advanced Energy Storage Innovation Center (NAESIC) have unveiled a 587 Ah semi-solid-state battery cell for energy storage, with the technology partners positioning it as the industry’s first semi-solid-state large-format storage cell at this capacity level. The launch took place in Beijing earlier on March 31.

The product was introduced as part of Inpow Battery’s new 587 Ah Boundless Series cell, which includes both a liquid-electrolyte version and a solid-liquid hybrid version. According to the company, the semi-solid-state cell is intended to deliver safety performance approaching that of an all-solid-state battery while remaining close to liquid-battery cost levels.  

At the core of the design is what Inpow calls its “QK Matrix” technology architecture, involving multiple battery components. The first element uses a nano-oxide solid electrolyte coating on the electrode surface to form a solid barrier that the company says can cut lithium dendrite penetration risk by 95%, suppress transition-metal migration, and improve thermal stability.

The second element relies on in-situ polymerized gel electrolyte technology, which forms a three-dimensional gel network after liquid precursor injection. Inpow said this reduces interface resistance by 90%, raises the flash point by more than 100°C, and leaves free electrolyte at less than one ten-thousandth of total content, bringing the cell close to all-solid-state behavior.  

Inpow also highlighted a broader design framework built around structure, current field, expansion-force control, and safety. The company said its stacked-cell architecture improves alignment precision, while a dual-tab and three-dimensional conductive network lowers internal resistance by more than 30%. It also claimed that cell swelling-force peaks can be reduced by more than 60%, helping extend cycle life.  

The company placed heavy emphasis on testing. For the semi-solid-state cell, Inpow reported no smoke, fire, or thermal runaway in a compression test at 10 times the national standard, a full-cut test using a high-speed saw blade, a 200°C hot-box test held for one hour, and a fire test using fuel flames above 1,000 °C. In some of those tests, it said, the cell still maintained normal voltage afterwards.  

Inpow’s R&D partner, the NAESIC, said they will use the innovation center’s validation platform to build a full-chain safety verification system spanning R&D, testing, and mass production, with the aim of accelerating further semi-solid-state storage cell iteration and commercialization. 

This new product is tied to a 6.5 GWh dedicated solid-liquid hybrid battery production line, which is said to be under construction, but with no completion and commissioning timeline unveiled.