Lots of stuff that could be used for battery building, too...kapton tape
https://www.aliexpress.com/item/4001238923655.html?gps-id=pcDetailFavMayLike&scm=1007.12873.140318.0&scm_id=1007.12873.140318.0&scm-url=1007.12873.140318.0&pvid=e98d28fd-8231-4071-b238-34dbf4d30d1d&_t=gps-id
cDetailFavMayLike,scm-url:1007.12873.140318.0,pvid:e98d28fd-8231-4071-b238-34dbf4d30d1d,tpp_buckets:668%230%23131923%2366_668%23888%233325%239_668%232846%238115%232000_668%232717%237563%23598__668%235153%2324260%23205
whole-pack heatshrink
https://www.aliexpress.com/item/32877833260.html?gps-id=pcDetailFavMayLike&scm=1007.12873.140318.0&scm_id=1007.12873.140318.0&scm-url=1007.12873.140318.0&pvid=7ac2e434-880a-41d1-8b81-e4092d8c7a30&_t=gps-id
cDetailFavMayLike,scm-url:1007.12873.140318.0,pvid:7ac2e434-880a-41d1-8b81-e4092d8c7a30,tpp_buckets:668%230%23131923%2394_668%23888%233325%239_668%232846%238115%232000_668%232717%237563%23598__668%235153%2324260%23205
insulation / barley paper
https://www.aliexpress.com/item/32827522392.html?gps-id=pcDetailFavMayLike&scm=1007.12873.140318.0&scm_id=1007.12873.140318.0&scm-url=1007.12873.140318.0&pvid=7ac2e434-880a-41d1-8b81-e4092d8c7a30&_t=gps-id
cDetailFavMayLike,scm-url:1007.12873.140318.0,pvid:7ac2e434-880a-41d1-8b81-e4092d8c7a30,tpp_buckets:668%230%23131923%2394_668%23888%233325%239_668%232846%238115%232000_668%232717%237563%23598__668%235153%2324260%23205
xt60s
https://www.aliexpress.com/item/33061763696.html?gps-id=pcDetailFavMayLike&scm=1007.12873.140318.0&scm_id=1007.12873.140318.0&scm-url=1007.12873.140318.0&pvid=7ac2e434-880a-41d1-8b81-e4092d8c7a30&_t=gps-id
cDetailFavMayLike,scm-url:1007.12873.140318.0,pvid:7ac2e434-880a-41d1-8b81-e4092d8c7a30,tpp_buckets:668%230%23131923%2394_668%23888%233325%239_668%232846%238115%232000_668%232717%237563%23598__668%235153%2324260%23205
ultrasonic welding machine
https://www.aliexpress.com/item/1005001406978326.html?gps-id=pcDetailFavMayLike&scm=1007.12873.140318.0&scm_id=1007.12873.140318.0&scm-url=1007.12873.140318.0&pvid=e98d28fd-8231-4071-b238-34dbf4d30d1d&_t=gps-id
cDetailFavMayLike,scm-url:1007.12873.140318.0,pvid:e98d28fd-8231-4071-b238-34dbf4d30d1d,tpp_buckets:668%230%23131923%2366_668%23888%233325%239_668%232846%238115%232000_668%232717%237563%23598__668%235153%2324260%23205
ok...well, that's twelve thousand dollars, plus shipping, so maybe it's not sucha deal.
but if you need one...
assorted low-s-count bms boards
https://www.aliexpress.com/item/32887463440.html?gps-id=pcDetailLeftTopSell&scm=1007.13482.95643.0&scm_id=1007.13482.95643.0&scm-url=1007.13482.95643.0&pvid=848dd765-3c30-42b6-a2c8-b166ff254f16&_t=gps-id
cDetailLeftTopSell,scm-url:1007.13482.95643.0,pvid:848dd765-3c30-42b6-a2c8-b166ff254f16,tpp_buckets:668%230%23131923%2394_668%23888%233325%239_668%232846%238115%232000_668%232717%237563%23598_668%231000022185%231000066058%230_668%233480%2315683%23409
balancer-only boards
https://www.aliexpress.com/item/32819855859.html?gps-id=pcDetailBottomMoreThisSeller&scm=1007.13339.169870.0&scm_id=1007.13339.169870.0&scm-url=1007.13339.169870.0&pvid=e25cf951-81ff-4ee9-8909-6803d38c6f65&_t=gps-id
cDetailBottomMoreThisSeller,scm-url:1007.13339.169870.0,pvid:e25cf951-81ff-4ee9-8909-6803d38c6f65,tpp_buckets:668%230%23131923%238_668%23888%233325%239_668%232846%238115%232000_668%232717%237563%23598_668%231000022185%231000066058%230_668%233468%2315618%23909
assorted smart bms
https://www.aliexpress.com/wholesale?catId=0&initiative_id=AS_20210203224042&SearchText=24s+smart+bms