"A portable battery should be considered to be removable by the end-user when it can be removed with the use of commercially available tools and without requiring the use of specialised tools, unless they are provided free of charge, or proprietary tools, thermal energy or solvents to disassemble it. Commercially available tools are considered to be tools available on the market to all end-users without the need for them to provide evidence of any proprietary rights and that can be used with no restriction, except health and safety-related restrictions."
I think a deposit for specialised tools is fair to ensure a return of the tools, other than that, there is nothing controversial here.