Do some reading here in the forum or search for "cr2" and/or "dilda batteries" and you'll find that this subject has been a really hot topic of late (it's best you do that prior to asking most questions that seem simple or you risk getting razzed for not doing your research or asking to be "spoon fed"...)
That said, there is an actual advantage to using the higher powered cr2's in a dilda, the drivers in them aren't regulated so you actually will realize a significant increase in power with the bigger batteries (just be sure to watch and feel for heat buildup, and it's best to limit the duty cycle of the laser when running the big cr2's, say 1 minute on and 1 minute off.)
There is a lot more technical info regarding this in the "red lasers" thread, again, go snooping and you'll be amazed the knowledge you'll find!
stop jumping on the guy, from his question he seems to have orderd 3.6v knowing the results and the guy gave him 3.7v instead, the truth is, the max voltage will be much higher when fully charged, so there wonb;t be much difference, theres already a risk, so i'm not gonna say safe, but it should work fine for your purposes