Porsche is said to have developed an electric Boxster prototype and may be interested in making a production version of the sporty EV.

According to Autocar, Porsche recently built an electric Boxster mule for testing purposes. The prototype worked well, but track tests showed it was ultimately slower than gas powered versions of the sports car, mostly due to weight.

A potential solution may lie in solid-state batteries, which are much lighter and more compact than lithium-ion batteries. Production-worthy solid-state batteries are still years out, but so is a production electric or hybrid Boxster, so perhaps Porsche will work out the solid-state equation over the next few years.

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Development of solid-state batteries will likely prove to be very important for Porsche (and many other automakers) going forward. VW Group recently said every car from its various brands will be electrified by 2030, and that includes Porsche. That means it will have to develop both an electric or hybrid Boxster and 911. Porsche purists may be able to overlook a slightly overweight Boxster hybrid or EV, but an electrified 911 will be under pressure to perform.

We may get an idea of what’s going on within Porsche’s EV department when the production version of the Mission E sedan arrives in 2019 or 2020. That car will be a performance-focused answer to other sporty EVs like the Tesla Model S P100D, with the Porsche claiming a 0-62 mph time of just 3.5 seconds and a range of over 300 miles for the concept.

This article originally appeared at AutoGuide.com.