SN Tripathi Memorial Lectures (2011)…

'BMW Has Cars Ready That Run on Hydrogen Cells...'
Dr CM Nautiyal

• The storage is 15% of car weight
• Fuelling takes about 8 minutes
• Left alone, half filled hydrogen tank will escape in 9 days.
• Runs 200 kms on hydrogen and 500 on petrol with highest speed of 230 kms/ h
• A biodiesel (body fat) based Ecoboat has been tested

What is A Fuel Cell?

A fuel cell is an electrochemical energy conversion device.A fuelcell converts the chemicals hydrogen and oxygen into water, and in the process it produces electricity. Most fuel cells in use today use hydrogen and oxygen as the chemicals.

How a battery differs from a Fuel Cell

A battery has all of its chemicals stored inside, and it converts those chemicals into electricity too. This means that a battery eventually "goes dead" and you either throw it away or recharge it.

With a fuel cell, chemicals constantly flow into the cell so it never goes dead. As long as chemicals flow into the cell, the electricity flows out of the cell.

Fuel cells are usually classified by the type of electrolyte they use.

Proton Exchange membrane Fuel Cell

The proton exchange membrane fuel cell (PEMFC) is one of the most promising technologies. This is the type of fuel cell that will end up powering cars, buses and maybe even your house. The PEMFC uses one of the simplest reactions of any fuel cell.

Other types of Fuel Cells
Alkaline fuel cell (AFC): One of the oldest designs. Has been used in the U.S. space program since the 1960s. very susceptible to contamination, so it requires pure hydrogen and oxygen. Also very expensive, so unlikely to be commercialized.

Phosphoric-acid fuelcell (PAFC): Has potential for use in small stationary power­ generation systems. It operates at a higher temperature than PEM fuel cells, so it has a longer warm-up time. This makes it unsuitable for use in cars.

Solid oxide fuel cell (SOFC): Best suited for large-scale stationary power generators that could provide electricity for factories or towns. This type of fuel cell operates at very high temperatures (around 1,000 deg C).