biology

Metal hydride fuel cell

Metal hydride fuel cell is a biology topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Metal hydride fuel cell rather than just read about it. In short: Metal hydride fuel cells are a subclass of alkaline fuel cells that have been under research and development, as well as scaled up successfully in operating systems. A notable feature is their ability to chemically bond and store hydrogen within the fuel cell itself.

Key takeaways

Metal hydride fuel cell belongs to biology; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Metal hydride fuel cell to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Metal hydride fuel cell from memory before moving on to harder problems.

Reference excerpt

Metal hydride fuel cells are a subclass of alkaline fuel cells that have been under research and development, as well as scaled up successfully in operating systems. A notable feature is their ability to chemically bond and store hydrogen within the fuel cell itself.

Characteristics Metal hydride fuel cells have demonstrated the following characteristics:

The ability to be recharged with electrical energy (similar to NiMH batteries) Operating at low temperatures (down to −20 °C) Fast "cold start" properties Ability to operate for limited periods of time with no external hydrogen fuel source, enabling "hot swapping" of fuel canisters

Performance Electrode active areas of metal hydride fuel cells have been scaled up from 60 cm2 to 250 cm2, enabling systems to be scaled up to 500 Watts. The scaling up of electrode active areas also provided capabilities to develop higher power fuel cell stacks, each with 1500 Watts of power. Metal hydride fuel cells have achieved a current density of 250 mA/cm2. To test durability, fuel cell stacks were successfully operated for more than 7000 hours.

Operating systems and applications

During the earlier phases of product development, there was a focus on single fuel cells and fuel cell stacks composed of multiple cells. The target applications included critical backup power for military and commercial applications. The next phase was to design and build complete fuel cell systems that could be taken outside of the laboratory. Initial 50 Watt laboratory-based demonstration systems were integrated into 50 Watt portable systems with more robust packaging and interfacing. Additional developments in both the fuel cell stack and system integration enabled a 1.0 kW system, complete with an inverter and onboard hydrogen storage using metal hydride storage canisters, to be operated and demonstrated in public. Further developments in metal hydride fuel cell systems were pursued for the field power needs of soldiers, resulting in a prototype system meeting deployment requirements. In tandem with product development, there was also a focus on developing capabilities for manufacturing and testing. Metal hydride fuel cell systems have been integrated into microgrid systems at military bases for testing and evaluation. Despite challenges, the military maintains an active interest in fuel cells for a broad range of applications, including unmanned aerial vehicles, autonomous underwater vehicle, light-duty trucks, buses, and wearable technology systems. Development of metal hydride fuel cell systems is continuing for military applications, with onboard hydrogen generation and fuel cells up to 5.0 kW.

See also Glossary of fuel cell terms Hydrogen technologies

References

External links Fuel Cell & Hydrogen Energy Association United States Department of Energy: Hydrogen and Fuel Cells Technologies Office Fuel Cell Seminar and Energy Exposition

Illustrations

Worked examples

Example 1 — a first encounter with Metal hydride fuel cell

Start with the simplest possible case. Write down what Metal hydride fuel cell claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In biology, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Metal hydride fuel cell before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Metal hydride fuel cell ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Metal hydride fuel cell

In research: Metal hydride fuel cell appears in biology research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Metal hydride fuel cell in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Metal hydride fuel cell is common in secondary-school and first-year university syllabi. It links to neighbouring topics Fuel cells, so understanding it makes those chapters shorter.
In everyday life: Look for Metal hydride fuel cell outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Metal hydride fuel cell in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Metal hydride fuel cell means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Metal hydride fuel cell out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Metal hydride fuel cell in simple terms?

Why does Metal hydride fuel cell matter?

Because it connects several biology ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Metal hydride fuel cell?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Metal hydride fuel cell.