The photo angle is not right - unable to guess the height of the battery. I presume it is 2/3rd the size of AA ( pen-torch cell ).
Here is a close match, but you will have to reuse the connecting pin from original battery.
If you can find a cordless phone repair shop, they will assemble you one. That is, solder 3 nos 1.2v ni-cd cells in series and tape them together to form a 3.6v battery. Again, they will reuse the connecting pin from the original battery.