COMPARE A FUEL CELL TO A BATTERY
Fuel cells are like batteries in that they are both devices that use chemicals to produce electricity. However, unlike batteries, fuel cells are set up to receive chemicals on a continuous basis and immediately convert those chemicals or “fuel” into electricity. Once the fuel stops getting to the fuel cell, the electricity also stops being generated. In contrast, a battery will primarily store its chemical or “fuel” supply and is typically recharged with electricity when it is depleted. There are exceptions and some batteries can be recharged by replacing electrodes and an electrolyte, but the “recharge” is performed for a relatively short time compared to its use, which is still essentially the opposite cycle behavior of a fuel cell.
Since a fuel cell isn’t limited by its built in fuel supply, it can consume more fuel and can operate at a much higher electrical output than batteries. For example, if you were to take a similarly sized battery and fuel cell, the fuel cell will produce 10 times more electrical power.
The first battery dates back about 2,200 years ago, namely the Baghdad battery. This early battery design needs a human to support it by adding fuel (citric acid from fruit) and metal strips into a clay pot “cell.” Based on the design, I would expect that this crude device required much more human attention than our modern batteries. In that sense, the adding of fuel to generate the electricity makes the Baghdad battery an early fuel cell. Though, it was shockingly just tarnished metal and fruit!
While the first modern fuel cell was invented in 1838, fuel cells did not see real improvements and use until more than 100 years later. A British engineer named Francis Thomas Bacon developed a Potassium Hydroxide formulation that improved the cells’ efficiency and corrosion challenges.
Even though Bacon started his work just before World War II broke out, it would be almost two more decades until the technology was transferred to two well-known Connecticut companies for NASA. General Electric powered the Gemini missions, and Pratt & Whitney systems powered the Apollo mission. The designs of these fuel cells are still used today on the international space station.
The fuel cells had a lot of advantages to our space program. First, the fuel cells produced clean energy. Years before green was in, NASA wanted to ensure astronauts were not choking to death in their tiny capsules. Second, fuel cells produce large amounts of power relative to their size versus traditional batteries. Third, a curious and useful byproduct of the fuel cell is water. That was a big selling point for NASA. The water that comes out of these fuel cells, supposedly, doesn’t taste so great. So NASA developed a revolutionary nutritional powder additive: Tang to the rescue!
Many different designs have been successfully deployed. The key components of fuel cells are electrodes (called the anode and cathode) and electrolytes (chemical that interacts with the electrodes). By selecting different materials, chemicals and designs for the application, engineers have been able to optimize the performance to cost ratios.
For example, some liquid-based fuel cells use a proton exchange membrane. This is ideal for water-based, room-temperature applications. Other fuel cells are solid state and operate at extremely high temperatures that rely on molten salt.
This bizarre-sounding design is useful in specific industrial processes where waste heat is readily available and can help drive the reactions in the fuel cells. Still other fuel cells use oxygen in the air as their cathode. This design eliminates the weight associated with the cathode components and is ideal for applications where weight is critical, such as fuel cell-powered cars and buses. Other fuel cells use diesel or biodiesel fuel as a source of hydrogen for the fuel cell.
STATE OF THE ART
Today fuel cells have come a long way from clay pots and rotting fruit. As mentioned, there are many different designs depending on the intended application. In general, fuel cells are reliable, efficient and powerful. They are even deployed as primary and secondary power sources for large industrial installations.
While modern fuel cells can produce large amounts of electricity relative to their size, they can rely on rare and/or expensive specialty materials to drive their performance. This can sometimes challenge their broader economic viability and prevents them from completely displacing more traditional forms of electrical generation such as coal, natural gas and nuclear.
For entrepreneurs looking to get into clean energy, there is a robust and diverse fuel cell industry in Connecticut. There are a number of larger producers such as Doosan Power in Windsor, CT and FuelCell Energy in Danbury, CT. In addition, there are several smaller fuel cell companies in the state.
Entrepreneurs interested in learning more about the opportunities in fuel cell technology should reach out to Joel Rinebold at the Connecticut HydrogenFuel Cell Coalition for more information.
About Dave Fazzina
I have spent the past 20 years as a materials engineer, an entrepreneur, a consultant and a part-time mad scientist.
I will discuss a bit of physics, chemistry technology and even some bio science as I explore the innovations that will be tomorrow’s hot new startups. I hope that the topics and discussions will inspire entrepreneurs to take chances and think big. Connecticut is home to some of the greatest inventors. While Nutmeggers are familiar with Samuel Colt and Eli Whitney, we shouldn’t forget that Danbury was Silicon Valley before Silicon Valley.