Lead Acid Batteries

In response to a letter (Aug. 16) concerning your first article of the series on electric vehicle (EV) technology, I must respond to several errors in the letter. First, lead acid batteries are not considered “the most hazardous of all” batteries, especially those currently in competition as electric vehicle batteries of the future. There are a number of higher energy density batteries (nickel cadmium, sodium sulfur, lithium polymer batteries) which also contain hazardous wastes as defined by the Resource Conservation and Recovery Act (RCRA) of 1976. Although lead acid batteries will make up the bulk of EV batteries early on, the plan will be to reclaim and recycle these batteries for economic reasons in addition to minimizing their impact on the environment. As other battery technologies come on the scene with improved performance characteristics, the relative percentage of lead acid batteries used in EVs will diminish.

Second, hydrogen sulfide is not generated in a typical lead acid battery during recharge. As the lead acid battery approaches full charge, hydrogen and oxygen gases are generated at the electrodes. In sealed or “maintenance free” lead acid batteries, these gases are recombined or controlled. In flooded lead acid batteries, hydrogen and oxygen gases are produced during excessive overcharge resulting in both loss of water in the battery and the potential for explosion if the required mixture of hydrogen is produced and a spark is present. Although these conditions constitute a hazard, they are easily controlled and effectively eliminated by the use of proper charging equipment and operating procedures.

MICHAEL J. DZVONIK

San Bernardino