IC for measure voltage of cells of 30S li-ion

Thread Starter

BrMisha

Joined Aug 13, 2022
6
Hi!
I'm building li-ion battery 30S4P and i need an BMS for that (preffered with some wired interface to get voltage of every cell). There are some on ali (https://www.aliexpress.com/item/1005002502679730.html) with dimensions 180x110x10 but i'm using the Gainta G3028 box and there is free space 135x80x20.

So, i want to build BMS my own with next functions:
  1. Monitoring voltage of every cell.
  2. Monitoring temperature.
  3. Balancing.
  4. Under and over voltage protection.
  5. Short circuit protection.
  6. Serial interface.

To balancing i can to use the HY2213-BB3A, but there is MCU (STM32) in my board so i can to implement the balancing logic on that (open transistor to discharge cell).
Temperature, voltage and short circuit will implemented on an STM32 too.

But how can i measure voltage of every cell? Using ADC of STM is a bad idea because max voltage is 126V and will power leak on res divider. May be is there some cheap MC to do that?
 

Irving

Joined Jan 30, 2016
3,130
30S is tricky. There are chips that do 16S, so maybe could have one for 15S upwards with isolated I2C... eg TI BQ79616, BQ76PL455A

These are used in TI's 100v reference design

Or look here for Analog Devices similar devices, they also have 16S products.

If you want to roll your own there are instrumentation amps that have >100v common mode capability... I've used this technique for 48v but no reason it cant be extended. With a gain = 1 their output is the cell voltage referenced to the 0v rail. A pair of 16:1 analog mux then drives two of the MCU ADC channels, giving 32 channels. Only downside is # of chips needed...

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