Electronic – How to charge this odd 4S Li-ion circuit

batteriesbattery-chargingbmscharginglithium ion

I am trying to make a battery pack that will power my electronics.
I need to make +7V and -7V. The +7V needs to have a decent amount of capacity.
I have proposed a 2S6P circuit for the +7V supply with a 1-Ohm STAR resistor network to balance the midpoints.
To make the -7V I just tacked a 2S circuit below ground.

To make things complicated each cell has a Battery protection IC BQ2970 to prevent reverse polarity insertion, short circuit protection any many other things.
So each cell in the schematic is actually representing Pack+ and Pack- in the second picture

I am designing my PCB to include a charger option. How do I go about charging this?
Is there an IC or circuit anyone can recommend?

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Best Answer

Well most big companies have battery charging chips, like

https://www.analog.com/en/parametricsearch/11471#/

Linear Tech also used to have equalizer chips. My RC-Battery charger has one.

In general... a µC, and a powerfull buck(boost) Stage can charge Lipo's that's how my RC-Battery charger works. You just need also to measure voltage and current as lipos need tight control. If you do it wrong, prepare to call the fire department.

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