Lead-Carbon: Battery Game-Changer

John Peterson sees Axion Power's lead-carbon battery technology as superior to all other current chemistries.

Published: 23-Jan-2009

For several months I’ve been telling readers that emerging lead-carbon battery technologies will be game changers in alternative energy storage. Last week, The Economist published an article about Axion Power International (AXPW.OB) titled “Lead-acid Batteries Recharged” and I found a recent report from Sandia National Laboratories on its side-by-side testing of lead-acid, lead-carbon and Li-ion batteries. Now that Axion’s management is talking to the press and Sandia is releasing independent data, I feel free to explain more fully why lead-carbon technology is so disruptive. I don’t like table pounding, but this is probably the most important Seeking Alpha article I’ve written.

Lead-carbon batteries are different from other types of batteries because they combine the high energy density of a battery and the high specific power of a supercapacitor in a single low-cost device. The primary goals of lead-carbon research have been to extend the cycle lives of lead-acid batteries and increase their power. Basically, developers start with conventional lead-acid chemistry and add carbon components to the negative electrodes. While the carbon components do not change the basic electrochemistry, they increase specific power and reduce a chemical reaction called “sulfation” that occurs during charging cycles and is the principal reason ordinary lead-acid batteries fail. Over the last several years, lead-carbon researchers have followed three different development paths:

  • Blending carbon additives into the lead sulfate paste that is used for negative electrodes;
  • Developing split-electrodes where half of the negative electrode is lead and the other half is carbon; and
  • Completely replacing the lead-based negative electrode with a carbon electrode assembly.
  • The DOE’s 2008 Peer Review for its Energy Storage Systems Research Program included a slide presentation from Sandia that summarized the results of its cycle-life tests on five different batteries including a deep-cycle lead-acid battery, two lead-acid batteries with carbon enhanced pastes, a split-electrode lead-carbon battery (the Ultrabattery) and an advanced lithium-ion (Li-FePO4) battery. While the tests performed by Sandia focused on smoothing power output from wind turbines and used a 10% depth of discharge from a 50% initial state of charge, which means more testing will be required before comprehensive comparisons are possible, the following graph highlights the magnitude of the cycle-life improvements that lead-carbon technologies offer today.


    The battery system was developed by CSIRO in Australia, built by the Furukawa Battery Company of Japan and tested in the United Kingdom through the American-based Advanced Lead-Acid Battery Consortium.

    The new batteries will make the GM Hybrid System nearly three times more powerful than the system it replaces. Pictured is 2009 Saturn Vue Green Line with Two-mode hybrid drive.

    Dramatic developments in stored-power technology make electric cars more viable than ever. Pictures is Th!nk Global's new Ox crossover vehicle.


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