Passive Balancer Design for 5 LFP Batteries

I need a professional to design a standalone passive balancer for my 5 LFP 72 Volt batteries. The main goal of this project is to extend the lifespan of these batteries while using them in series. 100AH battery with 1C discharge rate and 0.5C charge rate.

Ideal skills for this project include:
- Expertise in battery management systems
- Experience with designing passive balancers
- Knowledge about LFP batteries
- Ability to create standalone devices

Please provide a bid if you have the relevant experience and skills.