Low Temperature Operation of Lithium Start Batteries

The department of defense currently uses a number of models of vehicle start batteries with the “6T” form factor. These batteries are typically found in almost every vehicle in the DOD fleet and other systems that require 28VDC power. The use of power and energy on the battlefield is significantly changing and the Warfighter now requires a “start” battery that is used for more than just starting, lighting and ignition (SLI) for the vehicle. Lithium ion battery technologies are showing great promise in addressing these challenges by providing higher power capability for extended silent watch, battery monitoring and extended cycle life. One concern, however, is their ability to operate at low temperatures.

One of the most challenging aspects of battery use in military applications is their operation at extreme high and low temperatures. These wide temperature swings can potentially have a dramatic effect on cycle life and performance. One significant concern, especially for lithium ion technology, is the ability to provide sufficient cold cranking amps (CCA) and maintain their overall performance, including vehicle starting. Other important considerations at low temperature are the operation and accuracy of the battery monitoring system, whose electronics could potentially be sensitive in these operating conditions.

There are a number of ways to effectively mitigate cold weather operational risk, which include the use of advanced battery materials (anode/cathode material or electrolyte) or integration of heating systems within the battery. This paper will discuss the challenges for lithium ion batteries at low temperatures as well as present, with data, some effective means of overcoming this obstacle while not significantly impacting cost. To demonstrate the performance of lithium ion at low temperatures, data from cold chamber testing using the A123 Lithium Ion start battery will be presented.