Using MOSFETs as Switches for Batteries in Series

batteriesbattery-chargingmosfet

I am contemplating a way to build a new battery pack for a project that I am working on. However I think that I have run into a problem, but I am not sure.

I have a battery pack with about 27 batteries in series and 15 strings in parallel, as seen in the picture below (just a small sample), My goal, is to isolate (at least down to a small leakage current) a single battery in the pack in case it falls out of safe operating range.

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I am thinking about using N-channel mosfets for this job, but I don't know how well they will work in this type of circuit.

Will this work? If not, what would?

Best Answer

  • why do you want to switch both legs? Switching a single leg is sufficient to block all current.

  • You do know that power MOSFETs have a 'body diode'?

  • Have you thought about how you want to produce the gate voltage to drive you MOSFET switches? A typical power MOSFET needs ~ 8V at its gate.

  • I think your FETs are placed the wrong way round.

Summary: my answer would be that this probably is not going to work.

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