What happened

Nio (NIO 2.45%) shares had another positive week continuing the momentum seen this month. For the final week of June, Nio's American depositary shares were higher by about 11% as of Friday morning, according to data provided by S&P Global Market Intelligence.

That brings June's gains to nearly 25%. 

So what

Investors may be anticipating good news when the Chinese electric vehicle (EV) maker reports its monthly deliveries over this upcoming weekend. Nio's vehicle deliveries have shown a decline over the past four straight months, so investors seem to be expecting an end to that trend.

Another catalyst this week was news that Nio's energy subsidiary has signed an agreement with Chinese oil giant China National Offshore Oil Corporation (CNOOC) to help bolster its already expansive charging and battery swapping infrastructure in the country.

Nio vehicle in front of battery swapping station.

Image source: Nio.

Now what

Nio's battery swap stations provide customers with the option to lower the upfront vehicle cost by paying a monthly subscription for the battery and using the stations to replace drained batteries with freshly charged ones, a process that takes only minutes.

China Daily reports that the new agreement with CNOOC will leverage the oil company's experience and strengths to "provide Nio with reliable sites, technology and service support, helping to boost the rapid development of the charging and battery swapping network," according to CNOOC's refining division chairman Wang Weimin. 

Of course, investors want to see Nio's sales grow to make use of its charging technology and infrastructure. This week's run in the stock is likely also due to those investors seeing an improvement in monthly June deliveries, which will be reported this weekend. Vehicle deliveries have dropped for four consecutive months from more than 12,000 in February to just over 6,000 in May. If Nio reports a rebound in June, the positive momentum in the stock might just continue.