Chinese battery manufacturer Sunwoda says automakers are evaluating its polymer-based solid-state battery cell. According to Sunwoda Electric Vehicle Battery (SEVB), the cell has completed design and process verification. The subsidiary of Sunwoda Electronic disclosed the update on October 30 via the Shenzhen Stock Exchange’s investor platform. It did not name the automakers or disclose sample volumes.
Polymer Electrolyte Instead of Sulfide
The 20 Ah cell, called Xin Bixiao, reportedly reaches an energy density of 400 Wh/kg. Sunwoda specifies more than 1,200 cycles at an external pressure below 1 megapascal. The design combines a 12-micrometer polymer-composite membrane with a silicon anode. The cell is also said to have passed a 200°C (392°F) hot-box test. Sunwoda has not disclosed the temperature or charging rate used in the cycle tests. Cell-level results also do not show how a complete vehicle battery would perform.
Some sulfide-based solid-state designs require sustained external pressure to keep their components in contact. CATL, which is pursuing sulfide chemistry, recently reaffirmed its target of small-batch production in 2027.
Mass Production Plans for 2026 Unconfirmed
SEVB has set up a solid-state pilot line with an annual design capacity of 0.2 GWh. Sunwoda first presented the Xin Bixiao cell in October 2025. At the time, the company planned mass production with an annual capacity of 1 GWh for 2026. The latest update does not mention such a production start. The roadmap now lists a sulfide-based battery for 2027 and a cell exceeding 500 Wh/kg by 2030.
Sources:
https://carnewschina.com/2026/11/02/solid-state-battery-race-sunwoda-tests-polymer-cells-with-automakers-as-catl-targets-2027/
https://autotechinsight.spglobal.com/news/5284714/sunwoda-unveils-polymer-based-solid-state-battery-cell-with-400-wh-kg-energy-density
