Porsche is developing a fully electric 718 Boxster and 718 Cayman that will be launched by 2022 – and is considering offering them alongside mild-hybrid and plug-in hybrid versions of the current cars.
The next generations of the two-door roadster and coupé sports cars have for some time been thought to be among a range of future pure-electric models set to be spearheaded by the upcoming four-door Taycan and the Taycan Sports Turismo. However, Porsche chairman Oliver Blume has indicated that hybrid powertrains are also being considered.
“We have prototypes of the 718 running in electric now, and a hybrid prototype is being built,” he said. “If you look to the next generation of those cars it is possible, although it is not yet clear whether it would be plug-in hybrid or hybrid.”
The decision to pursue both hybrid and plug-in hybrid versions of the 718 Boxster and Cayman alongside the forthcoming electric models is understood to have been taken after an internal engineering study revealed that lithium ion battery technology is not yet sufficiently advanced to enable pure-electric versions to offer more than 186 miles of range without significant changes to the existing mid-engine platform architecture.
Porsche is now pursuing a plan that could see pure-electric Boxster and Cayman variants using the company’s new PPE architecture offered alongside updated versions of today’s models featuring hybrid and plug-in hybrid drivetrains.
The plan would mirror the move taken by Porsche with the next-generation Macan, which will continue to be produced on its existing MLB platform with new hybrid drivetrains while offering the choice of a pure-electric variant based on the PPE architecture.
Speaking about Porsche’s plan for the second-generation Macan, Blume said: “For at least two to three years we will have both. At that point, we can decide whether to upgrade the combustion engines to the new Euro 7 standard or go full electric. The pace that countries are changing is different – China wants electric now, Russia is in less of a hurry, for instance.”
The new mild-hybrid and plug-in hybrid drivetrains intended for the 718 models are developments of those already engineered for the larger 911, according to sources. The electrification measures are among changes designed to allow Porsche’s existing combustion engines to meet the upcoming EU7 emissions standards.
However, while the hybrid systems scheduled to appear on the facelifted version of the eighth-generation 911 early next decade are based around Porsche’s horizontally opposed six-cylinder petrol engine, those being earmarked for the new 718 Boxster and Cayman are set to use the smaller-capacity flat four engine introduced by Porsche in 2016.
Both units feature a 48V electrical system and disc-shaped electric motor integrated into a modified version of the existing Boxster and Cayman’s seven-speed dual-clutch automatic gearbox.
The mild-hybrid system has been conceived to provide an electric boost to the petrol engine for added performance potential and increased efficiency, albeit without the ability to provide an electric-only driving mode. The plug-in hybrid also provides electric boosting but has been built around a battery of sufficient capacity to offer extended pure-electric running.
Porsche’s plan to give the 718 Boxster and its fixed-roof Cayman sibling electric power originated from the 2011 Boxster E project. That machine featured a 121bhp electric motor with a range of 106 miles, although EV technology has moved on substantially since then.
More recently in 2017, Porsche developed the one-off Cayman e-volution. It had a claimed 0-62mph acceleration time of 3.3sec, a 120mph top speed and a range of 120 miles on a 38kWh lithium ion battery.
Despite the impressive performance credentials of the Cayman e-volution, concerns about its limited range led Porsche to pursue the development of solid-state batteries – both for future pure-electric versions of the 718 Boxster and Cayman as well as for an electric hypercar that is expected to appear in 2025 as a spiritual successor to the 918 Spyder.
Porsche insiders citing studies carried out by parent company Volkswagen say they anticipate a rapid evolution of lithium ion cells for an improved energy-to-weight ratio in the next generation of batteries. Estimates are that cell energy density both by volume and weight will increase by 25% from 2019 to 2025.
By 2025 they also expect the adoption of solid-state batteries to bring a further increase of 25%. This would allow Porsche to pack more energy in the same space with no additional weight penalty.
A £76 million investment by Volkswagen in QuantumScape has given Porsche access to the latest developments in solid-state battery technology.