Hi @leesav
According to this [https://www.amazon.com.au/dp/B08XQHTFDQ/ref=emc_b_5_t?th=1|link] the Maxkon 50L sensor bin (product code JAH5312-50L) is made by Ausway.
You could try [https://help.mydeal.com.au/hc/en-us|contacting] the manufacturer (or perhaps they're just the distributor idk) and ask them if a replacement battery holder is available as a spare part.
Best that I can find out is that it needs 6 x AA batteries to function, so the battery holder would need to accommodate this many and also be wired in series, presumably to provide the 9V power to operate the bin i.e. 6 x 1.5V AA battery so it may look something like [https://www.amazon.com.au/Corpco-Battery-Holder-Standard-Connector/dp/B07SRDPZ9Z|this] but a lot depends on the actual physical dimensions of the slot where the battery holder fits into the bin and also whether it is a snap connector fitting or it plugs in with a cable. There's no user manual online that I can find so you'd know how it would connect ;-)
Hopefully this is of some help.