China's top battery and electric car producer BYD Co Ltd said Monday its net profit in the first half of this year more than doubled from a year earlier despite a cooling auto market which dampened its second-quarter results.

In a filing to the Hong Kong stock exchange, BYD reported its net income totaled 2.4 billion yuan (US$353 million) during January to June. Its turnover also gained 50 percent to 24 billion yuan during the same period from a year earlier.

However, net profit for the second quarter of this year plunged an annual 58 percent to 720 million yuan while turnover dipped 8.4 percent to 11.6 billion yuan.

"In the second quarter, being the off-season for the auto market and as a result of the effect of the national macroeconomics control policies on the real estate industry and stock market, consumers were less willing to spend on non-necessities, therefore the growth in demand for automobile slowed," said Chairman Wang Chuanfu.

Shenzhen-based BYD, backed by billionaire Warren Buffett, sold 286,000 units in the first half of this year, up an annual 57 percent.

Its auto business boosted revenue by 46 percent to 13 billion yuan in the six-month period.