Have you ever wondered about how to make a solar powered car? The technology behind these remarkable vehicles of the future will change the course of history. Read on to learn more about how electric cars channel the electrical power of the sun to deliver a clean, efficient, and futuristic transportation solution to the world’s most difficult problem: climate change.
You’ll also learn more about the various technologies that comprise an electric car, including the engine system, electrical subsystems, software, and hardware. Each of these areas requires specialized knowledge to work properly. To start, let’s examine how solar cars function.
How Do Solar Cars Work?
Solar cars work by using solar panels as their sole source of electrical power. These panels use the sun’s radiation to produce usable electricity to power the motor. The vehicle stores excess power in special batteries that efficiently store and deliver electricity when the motor needs it.
Before proceeding further, you should know that the solar cars available on the market today have not yet reached commercial viability. There exist many scientific and engineering challenges associated with 100% solar cars, and you likely won’t find one on your neighbor’s driveway any time soon.
Here are a few of the most critical design and engineer challenges solar-powered cars face on their quest to achieve commercial viability:
- The Problem of Weight: The basic principle behind automobile weight and construction focuses on protecting the driver and passengers in the event of an accident. To that end, heavier weights can provide greater safety than lighter vehicles. For solar-powered cars, heavy materials would cause issues by requiring significantly greater solar panel coverage than what might reasonably exist onboard.
- The Problem of Efficiency: No 100% solar car exists on the road yet. The problem that all solar-powered vehicles face orients around the need for efficiency. Solar cell efficiency hasn’t reached the level necessary to feasibly generate the electricity required by the automobile.
- The Problem of Price: Among the many solar-powered vehicles under development, the one that might achieve commercial viability on a very limited scale would likely cost around $250,000. At a quarter of a million dollars, electric cars cost – on average – more than a single-family home in a reasonable neighborhood in most cities.
If you can get beyond these three main problems facing solar cars, you can learn a lot about where the technology is going and how it will eventually work to deliver a clean, efficient, and intelligent commute to the millions of drivers who want to take advantage of these new technologies.
A Closer Look at Photovoltaic Cell Technology
Photovoltaic cells (PVC) form the building blocks of the solar panels that coat a solar-powered vehicle. These cells take energy from the sun and convert it to electricity. Semiconductors manufactured from silicon form the basis for a PVC.
As energy from the sun strikes the semiconductors in the PVC, electros in the semiconductors break free and begin to flow throughout the system. This flow of electrons, in turn, generates the electricity that powers the electrical motor. Some electricity from this process also charges the vehicle’s batteries
The way this all works may seem complicated at first. Basically, the electrons freed by the light absorption from the sun’s rays flow in a specific direction. Metal contacts placed atop the PVC and on bottom then use that current for productive purposes. The cell’s voltage and the current of the flow of electrons define the wattage that the PVC produces.
The single-crystal silicon cell, one example of a PVC, follows this basic process. Silicon offers special properties that – especially in its crystalline form – allows for a crystalline structure thanks to the makeup of the silicon atom: 14 electrons in three different “shells.”
The outer electron shell of a silicon atom lacks four electrons (each shell contains eight in the ideal form). Since this last shell “needs” the additional four electrons, it will always look to share electrons with nearby atoms. You can think of the silicon atom as having four hands that hold it together with four atomic neighbors.
What Are Some of the Key Issues with Silicon in Photovoltaic Cell Technology?
Now that you understand the basic chemistry of PVC technology, you’re probably wondering about the basic issues that PVC technology has.
The problem with pure crystalline silicon stems from its poor conduction of electricity. Whereas conductors like copper allow for the easy movement of electrons, silicon tends to lock these electrons in place and causes them to not move around as much as other conductive materials.
One way that manufactures get around the problem of conduction with crystalline silicon focuses on allowing for impurities in the material. In other words, manufacturers combine other atoms with the silicon atoms. While you might thin that impurities pose problems, in this case they are necessary for the process to work correctly.
This mesh of silicon and other atoms allows some electrons to break free of their atomic bonds and travel randomly around the crystalline lattice to find another spot. These free carriers as they are known then allow for greater conduction.
The process by which engineers mix silicon with other types of atoms is known as doping. For example, silicon doped with phosphorous forms a type of silicon known as N-type silicon, so called for its free electrons. N-type doped silicon offers significantly greater conductive capacity than pure crystalline silicon alone.
Of course, there are other types of materials that manufacturers use to create PVCs. These materials include thin-film solar cells that use a specialized type of silicon known as amorphous silicon. Amorphous silicon lacks a crystalline structure. Other materials used in second-generation photovoltaic panels include gallium arsenide, cadmium telluride, and copper indium diselenide.
How to Build a Solar Car
At its most basic, building a solar car involves creating the following vehicular components:
- Solar Array: The PVC panels that coat the vehicle provide the harvesting mechanism by which the power of the sun flows through a lattice of impure silicon to deliver the wattage necessary to power the motor. Some of this electricity then flows to battery systems for storage and later use.
- Power Trackers: Power trackers act as an intermediary between the batteries and the solar array. They’re necessary for converting the energy collected from the solar into the voltage that conforms to the system’s requirements – otherwise the battery and motor won’t be able to use that energy.
- Batteries: After the power tracker does its business, the vehicle’s batteries spring into action. The batteries store the electrical power of the sun and make it available for later use by the vehicle’s motor and other necessary systems if applicable.
- Motor Controller: The vehicle’s motor controller can adjust the amount of electricity that flows to the motor. By modulating the amount of energy the motor receives, the controller can ensure that proper throttle action is achieved.
- Motor: Next up on the list is one of the most essential parts of a solar-powered vehicle: the motor. The motor uses the energy derived from the motor controller to turn the wheels of the vehicle. The amount of electricity that the motor receives from the controller determines the rotations per minute (RPM) of the wheels.
- Wheels: Everyone knows what these are! Solar-powered vehicles make use of lightweight wheels because of the low efficiency of current generation photovoltaic cell panels.
Of course, these components form the bare basics necessary to create an object that could pass itself off as a solar-powered vehicle.
Many other systems and elements are needed to create a fully-functioning human-scale solar-powered vehicle, including the control surfaces (such as a steering wheel and speedometer), interior seating, climate control (if necessary), and critical safety components. Additional software and hardware components are also necessary to create a safe and efficient vehicle.
How Does a Solar Car Stop?
As with any vehicle, a solar-powered car makes use of brakes to prevent the wheels from turning further and to slow down the vehicle whenever the driver needs to slow down. However, solar-powered cars also make use of the energy coming from the motor and channel it into the vehicle’s batteries for later use. By storing the electricity that would have originally arrived at the motor in a battery, the vehicle can allow for a technique known as “regenerative braking” whereby the batteries charge as the driver hits the brakes. Not a bad deal for solar vehicle!
Additional Reading for Those Interested in Developing Solar Cars
If you’re interested in learning more about developing a solar-powered vehicle, you’ll want to gain a solid understanding of the basic principles of chemistry, physics, and mechanical engineering. You can self-study for much of this material, but many colleges and universities also offer student organizations that work on a variety of experimental projects, including solar-powered vehicles.