Should I add insulation to lithium ion battery
This silver Duct tape is NOT thermally conducting. It is both thermally and electrically insulating plastic tape that looks like a conductor. It might be effective to stop air leaks.



The Li-Ion battery should never be operated in a thermally insulated case or in a high ambient temperature.

Always follow best practices found at Battery university and read more before making "grave errors"
(pun intended)