BMS for 48V to 400V lithium-ion battery pack

Batteries, Chargers, and Battery Management Systems.
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ENNOID
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BMS for 48V to 400V lithium-ion battery pack

Post by ENNOID » Feb 20, 2018 8:22 pm

Hi,

I'm looking for an open source BMS (Battery Management System) which would allow me to develop my own electric vehicle lithium-ion battery pack for voltages range from 48V and up to 400V.

The problem I am encountering right now is the lack of any medium voltage open source BMS with advanced functions available on the market as far as I know. After looking on the internet for documentation and related projects, the closest thing (open source) I have been able to find, is this very cool open source 12 cells BMS :

- https://github.com/DieBieEngineering/DieBieMS

This BMS has several interesting features that I am looking for:
- STM32 MCU configurable through USB with the user interface developed for the VESC-project
- CAN Bus
- Integrated SD card for DATA logging
- Integrated pre-charge and charge/discharge enable circuit.

Despite this, the rest of this BMS is limited to 12 cells /approx 48V and is using an outdated LTC6803 integrated chip.

Considering the voltage limitation of the DieBieMS, I am tempted to start the development of a similar BMS, based on it, but capable of handling a 400V/96S cells battery pack. For this, a Master and some daisy-chained slaves boards will be required instead of just one single board. The 16 cells "bq76PL455" from TI seems to be a better choice compared to the LTC6803 and this IC from TI is apparently used for the Tesla model S battery pack:

- www.ti.com/lit/ds/symlink/bq76pl455a-q1.pdf

So far, I just started the schematics on Kicad ... ( after all, I have a family to take care of, and a full time job + side business, but I still have some time somewhere for this kind of project)

The project files are available on github at :
https://github.com/EnnoidMe/ENNOID-BMS

Just for getting some attention, here is a related photo of a well documented TI evaluation BMS board that I would like to copy and operate with an STM32 MCU + some add-ons:
Image


Does some people here are interested for such a system in the open source ecosystem? Suggestions and ideas are very welcome :D


Thanks

ENNOID
10 mW
10 mW
Posts: 30
Joined: Dec 01, 2017 3:26 pm
Location: Quebec
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Re: BMS for 48V to 400V lithium-ion battery pack

Post by ENNOID » Feb 23, 2018 11:35 am

After looking on Github I found those threads related to high voltage BMS:

- https://endless-sphere.com/forums/viewt ... 14&t=63863
The part used has been discontinued... so that killed the project.

Another user from previous thread listed above "methods" started a thread about the use of an up-to-date LTC6811:
- https://endless-sphere.com/forums/viewt ... 8#p1288949
I personally think this chip is worth to look at, similar to TI bq76PL455, but only 12 cells capability instead of TI's 16 cells, for almost the same price tag. So I still think TI IC is a better choice... ( cheaper and less components for the same pack voltage...)

Another similar approach with outdated LTC6802, but only slave board:
- https://github.com/rickygu/openBMS
Project is quite old and no development since 2014...

Another semi-open source BMS far more advanced and maintained also based on LTC6811 and STM32 is this one:
- https://www.foxbms.org/typo3/index.php?id=4

This foxBMS is exactly what I was looking at and is nearly completed :D

ENNOID
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Joined: Dec 01, 2017 3:26 pm
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Re: BMS for 48V to 400V lithium-ion battery pack

Post by ENNOID » Feb 23, 2018 3:51 pm

This www.foxBMS.org project is badass:

Image

ENNOID
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Re: BMS for 48V to 400V lithium-ion battery pack

Post by ENNOID » Feb 24, 2018 4:26 pm

After a thorough inspection of this "FoxBMS", I do really see "german engineering" in this project... aka "system is a bit over-engineered" :roll:

The redundancy and safety is too much implemented in the hardware. I think their approach is just too expensive. (cells are monitored by two costly IC and two MCU for ensuring safety)

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