OS X Lion, Moutain Lion, Mavericks, Yosemite: deep sleep on low battery leads to crash
Does you SSD use a SandForce controller?  SandForce controllers seem to have some serious issues related to battery and sleep/hibernate activities, and you might (I repeat might) be seeing some of these problems coming up:

SandForce controller problems 

If you have a SandForce controller you might want to change SSD altogether, based on the info provided by the link above.