Re purpose Peugeot e-208 battery

[offgridandy]

Hi all and thank you for your welcome.

As I mentioned I have recently obtained a near new EV battery. Done only 1000 miles on a 2022 build date, so perhaps been charged 6 times.

The battery as built for Peugeot is as follows.

51 KWh.

Pack voltage 400V

Capacity 127.5Ah.

Total cells 216

Battery pack 108s2p

Modules 18

Module energy 2.74kWh

Module nominal 22V

Cells in module 12

Module configuration 6s2p

Format Prismatic.

Cell chemistry Lithium ion NMC

Cell nominal Voltage 3.7V

Standard charge and discharge cut off V 4.2V/2.75.

Cell capacity 62Ah

Battery voltage before dismantling was 388VDC and individual cells measure 3.59V

The battery as a whole is or was water cooled.

So, I have separated the 2 halves of the metal case and dismantled the battery down to packs/ modules.

Then I have partially, non, destructively, dismantled one module. Very careful removal of one module cover exposed the top of the cells. Installed across the top of the 6s2p cells is a circuit board. This is an interference fit onto a number of small pins on the top of the cells. With the circuit board removed one can see that the string has welded bus bars.

My basic plan is to upgrade my off grid power system from 24V to nominal 48V.

I am a long time user of Outback equipment, for it’s rugged build and reliability and simplicity and would wish to use their brand of inverter charger for the upgrade as I am familiar with their programming and menus etc.

The spec of the Outback VFXR3048E allows for DC charging on a scale from 42 to 68VDC. To support a larger load in the house I would have 2 inverters in parallel which also enables battery charging at a higher rate from a gen set (2X 45ADC).

2 of my modules in a series pack will connect to give a nominal 44V battery. So I could have 9 packs at 44V in parallel. If I have a low volt point for recharge set at 43.2 (3.6V per cell) (30%SOC) and top V for charging at 49.2 (4.1V per cell) then that fits in with the Outback VDC capability.

My first question is how best to use the modules.

If I could just use the 44v battery as indicated above would the circuit board (BMS) be useable or would I need to strip all the boards of the individual modules and replace.

If the circuit boards can stay then what else will I need as regards battery management? I don’t mind spending money but I only want to do things once. I also don’t spend my life constantly tinkering and resetting stuff. I need a system that will reliably power my house without switching itself off on a whim.

All ideas welcomed but go easy on me as I am new to the tech and also quite old and grey; but still learning, just slower. Remember I have 25 yrs experience driving a 24Kwh FLA battery and zero experience of Li ion.

 

[Roger and Out]

Interesting project

 

[meetyg]

NICE!
But please do some homework/research before handling Li-ion! One little mistake and you could (God forbid) burn your house down...
Lithium is great, but less forgiving than FLA.

As a previous owner of a Corsa-e (cousin to the e208, same battery), it's cool to see the inner workings of this battery!

As for your question, I would ditch the existing electronics and install a dedicated BMS to each module/pack.
That way you will have protection at the module level and be able to monitor the packs closely.

Good luck and keep us posted.

 

[offgridandy]

So I have done more research on these Peugeot battery modules. It wouls appeasr that each module has it's own slave BMS on board managing the 6s2p cells. Each module is connected in series (data on a daisy chain) linking back to the main BMS. The daisy chain consists of only 4 wires. So I deduce that the data link is simply sending and recieving data from the main management module. Therefore the actual BMS element is being run from the onboard slave. The slave board is also monitoring the internal temp.

The modules apparently have been developed in this way to allow for flexibility in design and service as modules can be exchanged as they all share a common data managment protocol.

The next trick is to find a way to hack the main BMS module. As I plan to simply use 2 modules in series to give me a 44v nominal pack I would think the main BMS will be expecting to see a 400V battery voltage which if not present would shut everything down. I think from reading the chip descriptiion that that HVDC is a parameter that can be reset to allow for flexibility when designing different batteries for different vehicles.

I have found 2 PDF files which cover this in detail way beyond my scope. I can post them if they are of use to someone.

Meanwhile I will have to go and learn how to Hack before I go further unless I can find someone who does this stuff, then I just "pay the man"