Hybrid EV Battery Pack Energy Enhancement

I'm seeking a knowledgeable professional for designing and developing a fuel cell supercapacitor battery pack that will be employed in a hybrid electric vehicle (EV).

1. Purpose:
This battery pack needs to serve as an energy storage system, with a fundamental purpose of capturing and holding energy for instances of braking, providing necessary power during acceleration, and augmenting fuel efficiency.

2. Technical Specifications:
The chosen professional should be versed in working with components possessing a low self-discharge rate. High energy density and high power density aspects would be considered additional beneficial characteristics but not a necessity for this project.

3. Lifespan:
The battery pack should be designed with a lifespan of 5 years in consideration.

The ideal freelancer should have solid experience and a deep understanding in the area of EV battery design, knowledge about low self-discharge components, as well as a proven track record in creating long-lasting battery packs. A background in hybrid vehicle energy storage systems would be a decided advantage for this task.