Chinese electric vehicle battery makers are quickly gobbling up market share from their South Korean rivals, largely buoyed by a surging demand at home, data showed Thursday.

According to Seoul-based market tracker SNE Research, China’s CATL retained its top spot in global sales in the January-September period as it supplied 119.9 gigawatt-hours of batteries, more than doubling from a year ago.

Its market share increased from 30.7 percent to 35.1 percent, widening the gap with Korea’s LG Energy Solution whose share suffered a 7.3 percent decline to 25.2 percent during the same period. The Korean firm whose key client includes Tesla supplied 48.1 GWh of batteries, a 14.1 percent growth on-year.

Chinese battery makers, led by CATL and BYD, drove up the overall sales, running high on the upbeat demands in China and the US that started from the third quarter of 2020. Of the top 10 battery makers, all six Chinese firms showed a whopping triple-digit growth in sales.

Two Korean battery makers in the top 10 list also posted upbeat growth in sales.

Sales of SK On, a key supplier to Hyundai Motor’s hot-selling Ioniq 5, almost doubled to 21.2 GWh to be ranked fifth with 6.2 percent market share, up from last year’s 5.7 percent.

Samsung SDI, the sixth in the rankings, suffered a slight decline in market share from 5.2 percent to 4.9 percent despite a 65.1 percent growth in sales during the same period. Its key clients include Audi and BMW.

“Both China and the US posted upbeat sales in September. Especially China showed a robust growth, offering a boon for Chinese battery makers,” SNE Research said in a report.

“Despite inflation fears and supply chain disruptions, the EV battery market has grown for the 27th straight month.”

The market tracker predicted Korean battery makers are focusing resources in the US and Europe as they are reviewing follow-up measures to respond to the Inflation Reduction Act of the US that offers hefty incentives to locally-produced batteries.