Chinese startup automaker Nio is recalling nearly 5,000 of the ES8 SUVs that it has sold in China following a spate of fires in their battery packs.

Nio says the pack assembly is the problem. A module in the pack can rub against a cable that samples voltage and eventually wear through the insulation—causing a short that leads to a fire. The company will replace the packs in affected cars over the next two months.

Nio has sold 17,000 ES8s in China since April 2018, but the recall only affects vehicles made through last October 19, because the company changed the pack design after that.

The automaker, which has been referred to as the Chinese Tesla, has faced a variety of challenges lately. Sales in the first quarter didn't live up to expectations, and the company put its planned third model, a sedan, on hold while it showed two new concept cars at the Shanghai auto show and ahead of it. The company is just rolling out its second model, a smaller SUV called the ES6.

In March, it abandoned plans to build its own factory in China and said it would continue to rely on fellow Chinese automaker JAC to produce its cars under contract.

The company also had to close one of its research offices outside San Francisco, even as it makes plans to expand outside China. Later in May, it teamed up with fellow Chinese automaker GAC to build cars in China and announced that it would postpone its planned U.S. launch.

Nio is one of the few Chinese automakers traded in the U.S., on the New York Stock Exchange.