The clamps and long bolts are available from Skandix (check shipping charges) and probably therefore elsewhere including Volvo dealers.
https://www.skandix.de/en/spare-part...steel/1068884/
https://www.skandix.de/en/spare-part...steel/1023212/
https://www.skandix.de/en/spare-part...screw/1023210/
Battery trays may well be worth producing since these seem to be NLA from Volvo and are inclined to rust.