Paper-thin panels that mold to a surface are critical for solar power to power devices in non-traditional places. Some of those unusual places could be the rooftop or spoilers of a next-generation vehicle, according to Ben Lenail, Director of Business Development, for solar panel manufacturer, Alta Devices, a Hanergy Company.  

Speaking at the World Safety Summit on Autonomous Technology, Lenail explains that a key ingredient that differentiates their approach is the use of Gallium Arsenide (GaAs), instead of Silicon as the semiconductor that converts light to electricity. According to Alta Devices web site, GaAs stands up to moisture and radiation and has a strong low light performance, low- temperature coefficient (works well under hot conditions) more efficient photon absorption and high output density.

Alta Devices has a unique toolset that grows a thin GaAs film on top of GaAs wafers, separates the thin film and assemble into customized solar modules. Their website states their tool is capable of producing hundreds of Watts of solar cells per hour. Their latest generation modules are up to 29% efficient (the amount of sunlight converted to electricity) and are extremely light with an unencapsulated weight to area density of 170 grams (6 oz.) per square meter.

From an application standpoint, the lightweight, flexible and robust nature of their thin-film solar cells are finding use in drones and airships at both low and high-altitudes, energy harvesting for low-power, Internet of Thing devices and wearables and in various applications in vehicles.

Lenail doesn’t expect these will be the primary power source for an electric vehicle but does believe they will be useful to provide a trickle charge to compensate for the increase in electronics due to the integration of autonomous features, such as Lidar.  According to Lenail, the robust nature of their product, along with its flexible and thin profile, will allow integration into the vehicle without impacting the design.

The upside is a vehicle with a range extension equivalent of perhaps 10 to 20%. This seems consistent with a NEDO, Sharp & Toyota Motor Corporation announced the testing of a Prius PHV outfitted with 860 Watts of thin-film solar cells and claims it can get as much as 35 miles of range extension. From a cost perspective these vehicle applications, it is still in the early days for the vehicle application so the end costs will still probably be measured in the thousands of dollars and it will be a supplement to and not a replacement for the local utility.

A glimpse of the solar vehicle future was seen this week in Australia, as the biannual Bridgestone World Solar Challenge. Hyper-efficient solar vehicles of various classes competed to make the 3,000 km journey from Darwin to Adelaide as efficiently and fast as possible. And, Alta Devices was there, powering the Stanford University Solar Car and providing a vision for how solar might integrate into the car of the future.*

*Unfortunately, the Stanford car suffered a battery fire, so it couldn’t finish the race.

Interview highlights:

00:41 – Lenail talks about their more common applications where their product goes today, particularly applications where low weight is necessary like drones.

01:07 – The unique properties and advantages of GaAs are discussed

02:15 – Airships as a cell tower? Yes, with motors to keep them in place, Lenail indicates there are many players looking at using lighter-than-air vehicles as virtual cell towers.

03:13 – Practical applications of solar panels within vehicles are given.

04:18 – If they are going to be in automotive, they are going to have to be durable. Just look at the cracked windshield in the video from a rock on a rural road.

04:51 – From a dollar per watt perspective, can it pay for itself?

05:27 – What sort of battery range extension might be possible using this technology?

06:10 – Does the 29% efficiency make up for the fact that you might not be positioned properly or are under trees?

07:06 – What about scaling production?