I certainly understand why you’re concerned. However wonderful this man can be, my guess is that you are wrestling with whether the relationship is worth the moments of rage. Whatever is going on with him, your boyfriend does not have the right to take it out on you. I hope you have the personal strength to make it clear to him that you will not tolerate it. When he pops off, I hope you can calmly tell him that you will talk to him when he can be respectful. Then leave. If your response is to tell me that it’s not safe to do that, then I urge you to get out of this relationship before you get hurt and he does something he’ll regret.
As for what may be wrong: In some people, depression is expressed as irritability and anger, not sadness. Then again, some people never learned to regulate their own emotions while growing up and still have tantrums that are developmentally more typical of teenagers. Still others bottle themselves up until they emotionally “burst.” Or your boyfriend may have his own issues that I don’t have enough information to process.
There are therapists who specialize in anger management and there are self-help groups that focus on the same issue. I don’t know what is the matter with your guy but I hope you can show him that it is to his benefit to get some help to learn how to express his feelings more appropriately and more in line with his age and position. His rage may well cost him his relationship with you and his career if he doesn’t.
I wish you both well.