Intro to Solar Arrays
- Calder Kitagawa
- Aden Chu
- Taiping Li
Solar Array
Our solar array consists of approximately 5 m^2* of Monocrystalline Silicon solar cells. At approximately 23% efficient and the sun providing 1000 W/m^2 of power, we expect to get approximately 1150 W from our solar array.
* Disclaimer : This article was written during an older vehicle cycle as of August 2024, MSXV currently is on a 4 m^2 solar array
Encapsulation
A significant part of the cost of a solar car's array is the module assembly and encapsulation. The two main companies that provide this are SunCat Solar and Gochermann Solar Technology. The main purpose of encapsulation include:
- Connecting individual cells to create modules
- Make cells more durable/easier to clean
- Apply an anti-reflective coating to reduce losses
An example of the benefits from the anti-reflection coating is described on Gochermann's website:
Solar Panel physics overview from NE242 (Semiconductor Physics)
TL;DR Silicon cells while not the most efficient (with a bandgap of 1.12 eV) are the most commercially viable and cheapest option for solar cells. A large amount of solar radiation is lost to atmospheric attenuation but enough reaches us to produce energy. Low bandgap materials generate lots of electrons but lose energy in the form of heat and only produce a small voltage with decent current. Higher bandgap produces a few high voltage electrons but the current is low. The most efficient bandgap for solar collection is 1.4 eV this would be an efficiency of 34% for a single junction cell at sea level (same as GaAS (expensive)). Silicon mainly absorbs in the UV and Visible spectra so working on a car indoors will not generate too much power as the attenuation of glass is quite high. MPPTs attempt to find the optimal fill factor by attempting to balance current and voltage to maximize the power generated.