Automotive lithium battery control set to grow in complexity

The big format lithium battery market will grow to be worth $100billion a year, based on recent surveys. Whilst some of these batteries will likely be used in applications including back up and remote power storage, automotive will represent a big quantity of the revenue.

Monitoring automotive batteries will turn into more and more important, but also increasingly complex, based on Erik Soule, general manager of Linear Technology's signal conditioning business unit. "A lot of poor things can happen in the event you don't manage these batteries properly."

Linear has begun to address the issues with the LTC6802, launched a couple of many years ago. "But the electronics have proved to be tougher than individuals thought for a number of reasons," he told New Electronics.

"For instance, you can find high voltages as well as the process requirements extreme precision, too as noise immunity. It's a issue when inverters switch at 20kHz due to the fact they radiate emi with a large variety of harmonics, so you also must filter all that out." Other requirements of these battery controllers consist of reliability, fault tolerance and diagnostics. "All these demands are being driven by the ISO26262 automotive security standard," he noted.

Along with answering such questions as 'is the cell charged?', 'how much vitality is left?' and 'are the cells balanced?', battery controllers may have to work with 1mV precision. "And the electronics in hybrid vehicles will probably be on 24/7 for 15 years perhaps," Soule added.

Linear is now working on new generations of its battery controllers. "We will almost certainly will need to build these on a process with 100V analogue capability, but with fine cmos," he said. "The devices could have greater noise immunity and will probably be greater at becoming able to meet safety necessities by way of the provision of built in self test features."