Coda Develops Thermal Technique For EV Batteries

Coda Automotive says it has a better way to maintain the temperature of lithium-ion car batteries.

            In a story posted on the web site, fastcompany.com, Coda engineers say they’ve recently filed patents on a new thermal management technique. The company, which is building an electric car with a 700-pound on-board battery, says it’s using a methodology similar to the kind employed in cabin air HVAC systems. To manage the battery, the HVAC system sends air to the center of the five-by-four-foot-wide battery pack, then lets it radiate out through channels incorporated along the battery’s width. The story says that Coda’s methodology represents a departure from competing battery-cooling techniques, which push air across the entire length of the battery. Because Coda’s system begins with air in the center and moves it across just half the battery’s length, it’s more effective.

            “By shortening the distance the air needs to travel, you reduce the thermal gradient in the pack,” a Coda engineer is quoted as saying.

            At first glance, thermal management of electric car batteries might seem like a minor issue, but in truth, it’s not. When we talked to drivers involved in BMW’s Mini E field trials last January, they were surprised by the effect of weather on their battery packs.

             “At first it seemed like a problem with the heater drawing too much energy,” one test driver told us about the effect of cold weather on the battery pack, “but it has become apparent that even with minimal or no usage of the heater, the MINI E’s range has been severely reduced.”