Shandong Weida, which trades in Shenzhen, rose with a daily limit of 10 percent on two days this week.

While Nio's shares traded in the US have been weak, its battery swap station supplier's shares traded in China's A-share market have been soaring for no apparent reason.

Shenzhen-traded Shandong Weida Machinery closed up 10 percent today, its largest daily gain limit.

Before this week, the stock was in a shaky period of about six months. It rose 10 percent on Monday and about 6 percent on Tuesday. It saw a cumulative gain of about 28 percent so far this week.

It is also worth noting that Nio is rapidly building its signature battery swap stations, the supplier of which is Shandong Weida.

Nio originally planned to have 500 battery swap stations in China by the end of the year, but that goal was revised upward to more than 700 in early July.

Today Nio added six new battery swap stations, bringing the total to 620, just 80 short of 700, according to CnEVPost data.