Chinese automaker BYD became the world's leading electric vehicle seller, pushing Elon Musk's Tesla to second place in the growing EV market.

BYD sold 638,157 electric or plug-in hybrid passenger vehicles in the first two quarters of 2022, company filings published on July 3 said, marking a 325% year-on-year increase.

Last month alone, BYD sold 133,762 electric or plug-in hybrid passenger vehicles, and in the first half of the year, the firm sold 323,519 battery electric vehicles and 314,638 plug-in hybrids.

In contrast, Tesla delivered a total of 564,743 vehicles in the first two quarters of 2022, figures released in their first and second quarter reports revealed.

The reports saw Tesla citing supply chain disruptions and factory shutdowns over the course of the year as the reason behind their struggle to meet demand.

As Tesla was hit by the volatility of the markets and supply chains, BYD's shares soared 36% since January, and the company was able to dodge the factory closures brought upon by the lockdowns over the COVID-19 pandemic.

On the other hand, Tesla's conveyor belts took a hit as its factories in Shanghai were forced to temporarily close in light of the coronavirus outbreak in the city at the start of 2022.

Tesla has also been mired in various controversies, such as having faulty autopilot AI systems that led to over a dozen crashes in the United States alone since 2018, leading to 15 injuries and one death.

The US National Highway Traffic Safety Administration (NHTSA) escalated in June its probe into Tesla's Autopilot function.

The NHTSA first began its investigation last year after 11 crashes took place with stationary first responder vehicles since 2018. These 11 crashes resulted in 17 injuries and one death, prompting the agency to begin investigating 765,000 Tesla cars almost 10 months ago.

The probe has now been widened to review data from 830,000 Tesla cars, and almost 200 new cases of accidents that involved Tesla cars that had the Autopilot functions turned on.

According to a release by the NHTSA, the investigation will "explore the degree to which Autopilot and associated Tesla systems may exacerbate human factors or behavioral safety risks by undermining the effectiveness of the driver's supervision."

Tesla also recalled 675,000 cars in the United States and China in 2021, prompting new questions about how safe the vehicles are.