Sion is a cancelled[2] project by the German start-up Sono Motors aimed at developing a partially solar-powered electric car.

[9] The experience gained during the test drives in 12 European cities (August 2017 to October 2017) is part of the further development.

[10] In 2017, several medium-sized investors joined Sono Motors, including the founder of the German energy service provider Juwi and the Böllinger Group.

[12] On May 9, 2018, Sono Motors announced the award of a major contract for the development and manufacture of a battery system for its solar vehicle to the German automotive supplier ElringKlinger.

[13] According to a press release from Sono Motors, on June 14, 2018, the minimum number of 5,000 reservations for Sion had been reached.

[19] In December 2022, the CEOs and co-founders of Sono Motors announced that they were unable to raise enough money to finance Sion, and asked fans to help continue the project.

[20] In February 2023, the company announced it would cease developing the vehicle, citing a failure to crowdsource sufficient funds.

The motor voltage is 400 V. With the rear wheel drive, a top speed of 140 kilometres per hour (87 mph) should be possible.

[21] The roof, bonnet and large parts of the outer shell of the body are equipped with highly efficient monocrystalline silicon cells (especially efficient in diffuse light, aiming to load 100% of their potential capacity at angles of incidence down to 70°) which are protected by a layer of polycarbonate.

The total area of the 330 photovoltaic modules is 7.5 square metres (81 sq ft) with an announced efficiency of 21%.

[22] Sono Motors pursues a one-product strategy, i.e. the car is expected to be produced only in one equipment variant.

Using SchuKo in other words European Household Plug method, the empty car battery fully charges completely up to 100 percent up to 13 hours, based on the socket capacity.

The BreSono does not require special care i.e. watering, fertilizing, trimming or exposing to sunlight due to avoided enzymatic reaction of moss.

The workshop manual for the Sion, including CAD data of all spare parts for 3D printers or CNC Milling, will be publicly available (license-free) with the delivery of the first models so that future repair costs may be expected to be reasonable.

[28] On request, the owner of the vehicle is able to use his / her mobile phone app to offer other people electric power (power-sharing), a ride-way (ridesharing) or to rent out his car (car-sharing).

[29] Sono Motors Founders intend to move part of their business toward the Netherlands, as there is a growing e-mobility market there.

They plan to captivate and intrigue the public interest so as to launch their zero-emission vehicle for sale, holding tours in 18 cities of the Netherlands and Germany.

The one-time purchase price of the battery was initially projected by Sono Motors to be less than €4,000,[34] but was later increased to a realistic estimate of €9,500.