Electric-car maker Tesla (TSLA -1.38%) delivered just over 22,000 vehicles in its second quarter, the company said on Monday in a press release. The figure was at the low end of Tesla's guidance for the quarter.

Tesla's second-quarter deliveries highlight several noteworthy trends in the company's vehicle sales, including a sequential decrease in total vehicle sales, as well as the first-ever sequential decrease in Model X sales.

Tesla Model S and Model X outside of the company's factory.

Model S (left) and Model X (right) outside of Tesla's factory. Image source: author.

Tesla's second-quarter deliveries

With total Model S and Model X deliveries during Q2 at just over 22,000 units, deliveries were up hugely on a year-over-year basis. Year-over-year growth during this period was 53%. But vehicle sales were down 12% compared to the first quarter of 2017.

Bar chart of Tesla's quarterly vehicle deliveries by model.

Data source: Tesla quarterly SEC filings and vehicle delivery updates. Chart source: author.

Tesla said the pullback in second-quarter deliveries was due to its introduction of a 100 kilowatt-hour (kWh) battery.

The major factor affecting Tesla's Q2 deliveries was a severe production shortfall of 100 kWh battery packs, which are made using new technologies on new production lines. The technology challenge grows exponentially with energy density.

Until early June, when Tesla resolved the production bottleneck, production for its vehicles was approximately 40% below demand levels, Tesla said. But after the issue was addressed, June orders and deliveries were "one of the best in Tesla history," management noted.

Interestingly, Tesla's late-2015 launched Model X suffered its first sequential decline in deliveries. Model X deliveries were up 116% year over year but were down 13% sequentially. Despite the pullback in Model X deliveries, Tesla is optimistic about the SUV's potential. "There appears to be substantial untapped sales potential for Model X," Tesla said.

With its second quarter behind it, Tesla's deliveries in the first half of the year were within management's guidance range for the period. In its fourth-quarter 2016 shareholder letter, Tesla said it expected to deliver between 47,000 and 50,000 Model S and Model X vehicles during this time. And Tesla maintained this outlook in its first-quarter shareholder letter. First-half deliveries were about 47,100.

Looking ahead: sales growth and Model 3

Going into the second half of the year, Tesla expects Model S and Model X deliveries to grow, even as it brings its Model 3 to market at the end of July. Tesla said it believes Model S and Model X deliveries will likely exceed Tesla's 47,100 deliveries in the second half. If this is the case, total Model S and Model X deliveries during 2017 would be above 94,200.

These optimistic expectations for Model S and Model X throughout 2017 suggest management doesn't anticipate cannibalization of the two flagship vehicles when the $35,000 Model 3 starts delivering to customers.

A black Tesla Model 3 makes a turn while being driven.

Telsa will start deliveries of its Model 3 at the end of July. Image source: Tesla.

Speaking of Model 3, Tesla used the delivery release as an opportunity to reiterate that the Model 3 met all regulatory requirements for production this week. In addition, Tesla confirmed that it expects to deliver about 30 Model 3 units at its Fremont factory on July 28. "More details to follow soon," Tesla said about the handover event.

As the Model 3 comes to market at the end of this month, and as Model S and Model X delivery growth slows, Tesla will increasingly rely on its upcoming Model 3 for sales growth. Tesla has previously said it expects to achieve a production rate for Model 3 of 5,000 vehicles per week before the end of 2017, and 10,000 vehicles per week at some point in 2018.