Environmental, health, and safety issues of sodium-sulfur batteries for electric and hybrid vehicles

Abstract

PrefaceThis report is the last of four volumes that identify and assess the environmental, health, and safety issues that may affect the commercial-scale use of sodium-sulfur (Na/S) battery technology as the energy source in electric and hybrid vehicles. The reports are intended to help the Electric and Hybrid Propulsion Division of the Office ofTransportation Technologies in the U.S. Department of Energy (D OFJEHP) determine the direction of its research, development, and demonstration (RD&D) program for Na/S battery technology .1The reports review the status ofNa/S battery RD&D and identify potential hazards and risks that may require additional research or that may affect the design and use of Na/S batteries. These reports were prepared by the Analytic Studies Division of the National Renewable Energy Laboratory and are one part of DOFJEHP' s RD&D program to work with industry to commercialize Na/S batteries. For example, data and information obtained through these reports will assist the DOFJEHP implement recommendations made by participants at government-industry meetings on sodium-beta batteries sponsored by the DOFJEHP [1 ]. The reports may also assist the DOFJEHP and the Ad Hoc Electric Vehicle Battery Readiness Working Group coordinate the RD&D needed to commercialize Na/S and sodium metal chloride battery technologies. z For these reports, it is important to define hazard and risk. A hazard is a source of risk, a substance or action that can cause harm. Risk, on the other hand, is the possibility of suffering harm from a hazard [ 2]. While the chemical and thermal hazards of elemental sodium are substantial, the risks involved in using sodium in a battery can be minimized through careful design, engineering, and testing. These reports on Na/S battery technology do not constitute a formal risk analysis, which usually includes estimates of the amounts, frequencies, and locations of the release of hazardous materials; the duration of exposures to these agents; estimates of the percentage of the population exposed and of dosage-response relationships; and a quantitative estimate of risk [ 2]. These reports provide a qualitative analysis of hazards and risks that must be addressed before Na/S batteries can be deployed on a commercial scale. These reports are intended to help DOFJEHP set management priorities for the RD&D of Na/S battery technology by identifying potential hazards and risks, by reviewing RD&D in progress to address these hazards and risks, and by recommending RD&D needed to help minimize these hazards and risks.This volume covers the in-vehicle safety issues of electric vehicles powered by Na/S batteries. The report is based on a review of the literature and on discussions with experts at DOE, national laboratories and agencies, and private industry. It has three major goals: (1) to identify the unique hazards associated with electric vehicle (EV) use; (2) to describe the existing standards, regulations, and guidelines that are or could be applicable to these hazards; and (3) to discuss the ...

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