This is a question that needs a literature search rather than a question on RG. There's a systematic review from Article Risk factors in relation to an emergence of bipolar disorder...
but it rates the evidence for traumatic head injury as tentative. A review this year doesn't mention it as a risk factor at all.
Article Environmental Risk Factors in Bipolar Disorder and Psychotic...
And I found those in three minutes. I'd recommend you head off and do some lit searching.