Chinese electric-vehicle (EV) maker NIO (NIO -7.85%) said that it set another record for deliveries in December, after it successfully implemented a production boost earlier than it had planned ahead of rival Tesla's China launch of its Model Y SUV.

NIO delivered 7,007 vehicles in December, a new monthly record for the company and more than double its year-ago result, after boosting its production capacity in a bid to keep up with high demand for its upscale electric SUVs. That total included 2,505 examples of the EC6, a sporty crossover introduced in September that is now the company's best-selling model.

NIO's CEO, William Bin Li, had said during the company's third-quarter earnings call in November that it was working with suppliers to increase its monthly production capacity to 7,500 vehicles, and that it hoped to hit that production target early in 2021. But early in December, Li said that NIO was going to try to get that increase in place before the end of 2020, an effort that was clearly successful. 

The NIO ET7 show car from 2019, a sleek white electric sedan.

NIO will unveil its next new model, a sedan, on Saturday. It might be the production version of the ET7 concept it showed in 2019. Image source: NIO.

In a statement, Li said that over 40% of customers chose the company's battery-as-a-service subscription option in December. The option allows a customer to buy a NIO vehicle without a battery pack, at a reduced up-front price, if the customer purchases a subscription to NIO's battery-swap service. 

NIO has over 150 automated battery-swap stations up and running in China; the stations can swap out a NIO's battery pack for a fully charged new one in about 3 minutes. 

NIO is expected to reveal it next new model, a sedan, at its annual "NIO Day" event on January 9. The company will also update customers and investors on its autonomous-driving development and other technology efforts at that time, it said.