As autonomousperson stated, we need more information, links, photo's, even some measurements would help.
The rechargable lithium-ion batteries that most lasers use, are identified by their size in millimeters, I.E. a 18650 size battery would be approximately18mm in diameter x 65mm long depending on brand, and whether it's protected or not.
If your laser happens to be one of the small "pen" style units, it may use standard 1.5V AAA size batteries.
Also, and maybe most importantly, be aware of the battery polarity that your laser requires, most 532nm lasers have the positive (+) end of the battery pointing towards the tailcap!