The wars in Iraq and Afghanistan have accelerated field deployable technologies to enhance command and control, improve detection and identification, provide fire control that is more precise and reduce individual exposure. These devices have heightened the need for more reliable power, and as a result, the average soldier on a 72 hour mission is required to carry anywhere from 25 to 27 pounds of batteries. This of course is in addition to ammunition, water, food rations, body armor and other essentials. The problem has grown in proportion to the increase in technology enhancements, and in many platoons; commanders have designated individuals as “battery mules”. The Army has not ignored the issue and has been actively seeking solutions; as a result, we are witnessing accelerated development and deployment of fuel cells that are man portable, from a number of companies. One example of the new entries is the M-25 fuel cell developed through a joint venture between DuPont and Smart Fuel Cell, AG.

The M-25 is part of an integrated body-worn power source, that can be carried by the soldier, that combines DuPont’s direct methanol technology with SFC’s commercially proven fuel cell systems, products and integration expertise. This technology has enabled a significant weight reduction when compared to conventional battery systems for multi-day missions. The M-25 delivers quiet and continuous energy, and offers independent standalone functions such as remote area battery charging and power. SFC AG is not a newcomer to portable fuel cell technology and has delivered a practical fuel cell, that it calls Jenny, to its military customers.

The Jenny is the predecessor to the M-25. It has been in actual field use since 2008, and according to the company has met rigorous military requirements. This fuel cell operates in one of two configurations. In the first application, the cell is connected to a rechargeable battery, a hybrid arrangement; in this application, circuitry incorporated in the fuel cells continuously monitors voltage; dispensing power as needed to maintain the host battery fully charged. In the other configuration, the fuel cell will supply power directly to devices that it connects with, in other words there is no intervening power source, like a rechargeable battery.

Like other Smart Fuel Cells products, the M-25 uses a direct-methanol technology. In the simplest terms, the fuel cell uses a 76% methanol and 33% water mixture, which it consumes via electro-chemical processes, to produce electrical energy. Smart Fuel Cell developers have achieved an 80% weight reduction over comparable output lithium-ion technology. This is a significant benefit to the soldier warrior. However, I have some concerns with this very promising technology and my concern extends to all fuel cells that use combustible fuels or potentially explosive hydrogen gas mixtures.

Let’s talk a little about Methanol, not to be confused with ethanol, which we can drink. Methanol has a chemical formula of CH3OH; it is the simplest of all the alcohols, and is extremely light. Methanol is also very stable and remains a liquid from -97ºC to 64.7°C at sea level, so you don’t need special storage devices. Producing current from a methanol + water mixture is relatively complex from an engineering perspective; however, what we are trying to accomplish chemically is oxidizing the methanol to free Hydrogen atoms. Hydrogen contains one proton, carrying a positive charge, and one electron, carrying a negative charge. The protons are collected at the anode of the fuel cell and the electrons are collected of the cathode, thus providing the current. Although conceptually this is a very straightforward matter, the engineering is quite formidable and requires complex catalysts, selectively permeable membranes, and sophisticated circuitry to transfer electrons from the cathode. We also need a way to deal with the byproducts of carbon dioxide, CO2 and water, H2O.

The reason that I subjected you to this level of detail is to give you an understanding that current fuel cell technology relies on the hydrogen atom to supply the single electron that becomes current. This is true of all hydrogen-based fuel cells. However, as we know, hydrogen has its issues; the Hindenburg disaster in 1937 is one example of this. The explosions on the Oscar class Russian submarine, the Kursk, which sank in the Barents, with all hands lost is a more recent example.

Currently, the only sources of fuel for the cells are liquid hydrogen, H2, and hydrogen enriched compounds, where hydrogen bonds can be easily broken to release hydrogen atoms. Methanol is such a fuel. SFC’s Direct-Methanol technology used in the M-25 is powered by 300 milliliters of a methanol + water mixture. Ingestion of just 10ml of methanol will probably blind you and 100ml will kill you. This is to give you an idea of the toxicity Methanol is highly toxic and highly combustible; producing a very hot colorless flame, it also emits a distinctive odor. Soldiers carrying hydrogen-based fuel cells, of any designer, are at risk of serious injury, should they take a hit from a tracer or be exposed to white phosphorous, etc. If the fuel cell is operating in a hybrid configuration, connected to a host rechargeable battery, like a lithium-ion power source, the problem is compounded.

As a community, of active duty personnel, retired and former military, we know that details are often overlooked to expedite a solution. Power source R&D needs to be a priority, if technology is to continue its success in the field. However, we must guard against laxity and we cannot allow ourselves to create a Ford Pinto.

As of this writing, I have not seen test results or test data to show that fuel cells of any design are being subjected to gunfire and the effects of pyrotechnics. All aspects of fuel cells need to be tested using a comprehensive test plan that includes operator survivability, and not just electrical performance.

Story By: Sal Palma
© Sal Palma, 2009. All rights reserved August 4, 2009