Working of Fuel Cell Car

Fuel Cell Stacks

This is the heart of the hydrogen fuel cell car—the fuel cell stacks. Their maximum output is 86 kilowatts, or about 107 HP. Because hydrogen fuel cell stacks produce power without combustion, they can be up to twice as efficient as internal combustion engines. They also produce zero carbon dioxide and other pollutants. For more information on the stacks.

Fuel Cell Cooling System

This has several parts. Perched at an angle at the front of the vehicle is a large radiator for the fuel cell system, while two radiators for the motor and transmission lie ahead of the front wheels below the headlights. The car also has a cooling pump located near the fuel cell stacks to stabilize temperature within the stacks.

Ultra capacitor

This unit serves as a supplementary power source to the fuel cell stack. Like a large battery, the ultra capacitor recovers and stores energy generated during deceleration and braking. It uses this energy to provide a "power assist" during startup and acceleration.

Hydrogen Tanks

Space in a car is limited, yet hydrogen is the most dispersive element in the universe and normally requires lots of room. A challenge for manufacturers is how to compress the gas into tanks small enough to fit in a compact car and yet still provide enough fuel for hundreds of miles of driving between refueling. The two high-pressure hydrogen tanks in this vehicle can hold up to 3.75 kilograms of hydrogen compressed to roughly 5,000 PSI—enough to enable an EPA-rated 190 miles of driving before refueling, the manufacturer says.

Electric Motor

(General area only—motor not visible) The electric motor offers a maximum output of 80 kilowatts, enabling a top speed of about 93 miles per hour. The manufacturer says this vehicle can also start in subfreezing temperatures (down to about -4°F), a perennial problem in fuel cell prototypes. Being electric, the engine and the car as a whole are quiet, with none of the vibration or exhaust noise of a gas-powered automobile.

Air Pump

(General area only—air pump not visible) Run by a high-voltage electric motor, this pump supplies air at the appropriate pressure and flow rate to the fuel cell stacks. The air, in turn, mixes with the stored hydrogen to create electricity.

Humidifier

The humidifier monitors and maintains the level of humidity that the fuel cell stack needs to achieve peak operating efficiency. It does this by recovering some of the water from the electrochemical reaction that occurs within the fuel cell stack and recycling it for use in humidification.

Power Control Unit

(General area only—power control unit not visible) This controls the vehicle’s electrical systems, including the air and cooling pumps as well as output from the fuel cell stacks, electric motor, and ultra capacitor.

Cabin

With the fuel cell stacks hidden beneath the floor and the hydrogen tanks and the ultra capacitor beneath and behind the rear seats, respectively, the four-passenger cabin is isolated from all hydrogen and high-voltage lines. Hydrogen gas is colorless and odorless, and it burns almost invisibly. In case of a leak, therefore, the manufacturer has placed hydrogen sensors throughout the vehicle to provide warning and automatic gas shut-off. Also, in the event of a collision, the electrical source power line shuts down.

Hydrogen Filler Mouth

(Not visible—located on other side of vehicle) Drivers would fill the car with hydrogen just as they do with gasoline, through an opening on the side of the vehicle. The main difference is that a fuel cell car must be grounded before fueling to rid the car of hazardous static electricity. For this reason, this model has two side-by-side openings, with the latch to open the hydrogen filler mouth located inside the opening for the grounding wire. The manufacturer says filling up this model’s two tanks at a hydrogen filling station would take about three minutes.

Note

The limited-production vehicle seen in this feature is a Honda 2005 FCX, which is typical of the kinds of hydrogen fuel cell automobiles that some major automakers are now researching and developing. With such vehicles at present costing about $1 million apiece, none is currently for sale, though hundreds of fuel cell cars are now undergoing tests on the world’s roads.

Artificial Leaf Solar Power | Artificial Leaf Produce Electricity

Photosynthesis:

Photosynthesis is the process by which plants, some bacteria, and some protists use the energy from sunlight to produce sugar, which cellular respiration converts into ATP, the “fuel” used by all living things. The conversion of unusable sunlight energy into usable chemical energy, is associated with the actions of the green pigment chlorophyll.

They release molecular oxygen and remove CO2 (Carbon Dioxide) from the air.


ATP: Adenosine Tri-Phosphate (ATP) Here the energy is stored in living systems; it consists of a Nucleotide (with Ribose sugar) with Three Phosphate groups.

Why is photosynthesis important:

Nearly all living things depend on the energy produced from photosynthesis for their nourishment. Animals need the plants for food as well as oxygen. Only green plants are able to change light energy into chemical energy stored in food, thus they are vital to life on Earth.

Solar cells:

Conventional solar cells are also called as Photo Voltaic Cells. These cells are made out of semiconducting material, usually silicon. When light hits the cells, they absorb energy though photons. This absorbed energy knocks out electrons in the silicon, allowing them to flow. By adding different impurities to the silicon such as phosphorus or boron, an electric field can be established. This electric field acts as a diode, because it only allows electrons to flow in one direction. Consequently, the end result is a current of electrons, better known to us as electricity.

Drawbacks of Solar cells:

They can only achieve efficiencies around 10% and they are expensive to manufacture. The first drawback, inefficiency, is almost unavoidable with silicon cells. This is because the incoming photons, or light, must have the right energy, called the band gap energy, to knock out an electron. If the photon has less energy than the band gap energy then it will pass through. If it has more energy than the band gap, then that extra energy will be wasted as heat.

Artificial Leaf:

Mixing of Photosynthesis + Conventional Solar Cells + Hydrogen Fuel Cell

This Leaf device combines a commercially available solar cell (Silicon) with a pair of inexpensive catalysts made of Cobalt and Nickel that split water into Oxygen and Hydrogen. The hydrogen can be stored and used as an energy source. (For example to power a fuel cell).

The collection and storage of the sun’s energy as hydrogen fuel is a key step in overcoming one of the limitations of solar power — it generates energy when the sun is shining, but it needs to be stored somewhere to be useful at night and in cloudy weather. Batteries are one place to store the energy, but it is limited. Storing solar energy as hydrogen fuel could be an answer for producing the electricity continuously.

Using this approach, a solar panel roughly one square meter bathed in water could produce enough hydrogen to supply electricity for a house.

Polymer Electrolyte Membrane (PEM) Fuel Cells (PEFC) | Proton Exchange Membrane (PEM) Fuel Cells

Polymer electrolyte membrane (PEM) fuel cells—also called proton exchange membrane fuel cells—deliver high-power density and offer the advantages of low weight and volume, compared with other fuel cells. PEM fuel cells use a solid polymer as an electrolyte and porous carbon electrodes containing a platinum catalyst. They need only hydrogen, oxygen from the air, and water to operate and do not require corrosive fluids like some fuel cells. They are typically fueled with pure hydrogen supplied from storage tanks or on-board reformers.

PEM Technology:

Polymer electrolyte membrane fuel cells operate at relatively low temperatures, around 80°C (176°F). Low-temperature operation allows them to start quickly (less warm-up time) and results in less wear on system components, resulting in better durability. However, it requires that a noble-metal catalyst (typically platinum) be used to separate the hydrogen’s electrons and protons, adding to system cost. The platinum catalyst is also extremely sensitive to CO poisoning, making it necessary to employ an additional reactor to reduce CO in the fuel gas if the hydrogen is derived from an alcohol or hydrocarbon fuel. This also adds cost. Developers are currently exploring platinum/ruthenium catalysts that are more resistant to CO.

PEM Fuel Cell Applications:

PEM fuel cells are used primarily for transportation applications and some stationary applications. Due to their fast startup time, low sensitivity to orientation, and favorable power-to-weight ratio, PEM fuel cells are particularly suitable for use in passenger vehicles, such as cars and buses.

Disadvantages of Fuel Cell:

A significant barrier to using these fuel cells in vehicles is hydrogen storage. Most fuel cell vehicles (FCVs) powered by pure hydrogen must store the hydrogen on-board as a compressed gas in pressurized tanks. Due to the low-energy density of hydrogen, it is difficult to store enough hydrogen on-board to allow vehicles to travel the same distance as gasoline-powered vehicles before refueling, typically 300–400 miles. Higher-density liquid fuels, such as methanol, ethanol, natural gas, liquefied petroleum gas, and gasoline, can be used for fuel, but the vehicles must have an on-board fuel processor to reform the methanol to hydrogen. This requirement increases costs and maintenance. The reformer also releases carbon dioxide (a greenhouse gas), though less than that emitted from current gasoline-powered engines.