How can I stack 3 coin cell batteries?

[IronEagle19]

I am doing a handheld project design and I would like to know how I can stack THREE 3V coin cells to make a 9V package. My device will draw a maximum of 100mA. I know this can be done some way. Please don't suggest a 9V PP3 battery. I need the device to be as light and compact as possible.

 

[pranam77]

Stack it one over the other and use shrink wrapping tube to secure all the 3. For better connections you may spot weld the terminals and take wires as shown in the photos below....cheers

 

[IronEagle19]

Thank you! I didn't think about that. I will try that out.