Flat, flexible Lithium-ion batteries, hum?

Hello,

I am new to this forum, but very interested in what you have been discussing. I am a caver and am constantly looking for a better light.

In my search, I came across these batteries, Flat, flexible lithium-ion batteries. They are being marked towards cell phones and laptops, but I wonder how they may perform with lights.

Here's a link. Click the products link. http://www.macroenergy-tech.com/

I am not very knowledgeable about electronics and such. So, I was hoping that one of you whiz kids could tell me if my dreams are possible?

I am dreaming of a light that would have 3-5 LEDs (for most of the time) and a bright incandescent spot (for occassionally turning on). I also need it to be small, light weight, water proof and rechargeable. I hate having the batteries on the back of my helmet or on a belt. This is why the flat, flex Li-ion would be so great. I could mount it inside the helmet.

I suppose that if the batteries were the right shape, several could fit inside the helmet. Heck, if someone was really ingenious, they could make a battery in the shape of a helmet

Anybody have any experience with these batteries or suggestions/advice for me?

Thanks a bunch.
Scott "Dark Sucker" McCrea