In the ramp-up to the launch of the Chevy Volt and Nissan Leaf, a great debate seized the engineering community: was Nissan opening itself to problems by not including a active thermal management system for the Leaf’s battery pack, or was Chevrolet’s liquid-cooled approach simply adding unnecessary complexity? Well, thus far, the verdict seems to be in Nissan’s favor. Though Leaf has been troubled by some dissatisfaction with its real-world range, the Volt has endurd the first technical semi-scandal of the plug-in era, when federal regulators found that ruptured coolant lines could cause fires. Now the liquid-cooled approach is hitting its second challenge, as Fisker’s battery supplier A123 Systems is warning in a letter [PDF] that
some of the battery packs we produce for Fisker Automotive could have a potential safety issue relating to the battery cooling system.
In its warning letter, A123 explains
Specifically, certain hose clamps that are part of the battery pack’s internal cooling system were misaligned, positioned in such a way that could potentially cause a coolant leak. Over time, it is possible that in certain rare circumstances, this coolant leak could potentially lead to an electrical short circuit.
There have been no related battery performance or safety incidents with cars in the field. However, A123 and Fisker are committed to safety and are taking immediate, proactive steps to prevent any issue from occurring.
We have developed a confirmed repair for this situation. In the short time since recognizing this potential safety issue, the root cause was quickly identified, a fix has been developed and corrective action is well underway.
In total, fewer than 50 customer cars are involved in this action.
Bloomberg adds that the problem has been caught relatively early, as Fisker is still producing just 25 Karmas per day at Valmet’s contract-manufacturing plant in Finland. Production is scheduled to hit 60 units per day sometime next year. Meanwhile, A123 is also preparing to start supplying batteries to Chevrolet’s Spark EV, so GM is probably breathing a sigh of relief that it’s catching battery problems before that contract starts. Still, these early issues with battery cooling systems are tipping the debate in favor of the cheaper, less-complex passive cooling approach… for now, anyway. When Summer arrives and temperatures rise, we’ll be keeping an eye on the Leaf fleet to see if problems pop up there.