Toddler hitting head on ground

My second born has very strong emotions and always has. He started throwing screaming tantrums around 7 months old and will throw himself backwards to the ground violently when he’s upset. Since probably 11 or 12 months old he will hit his head on the ground repeatedly when he’s mad. I thought he would’ve grown out of it by now but he’s 17 months and still doing it. He gets a lot of bruises on his head from it and I’m just wondering at what point should I be concerned? Obviously I would be concerned if he showed signs of a concussion but he doesn’t. He just won’t stop his tantrum unless I let him hit his head on the ground, wall, door, whatever it is. I’ve tried holding him, he will thrash at me and try his absolute hardest to get out of my arms to get to the floor. I’ve tried redirecting him but it makes him scream even more. He literally won’t stop until he gets to hit his head on the ground like 5 times.

I’m just extremely tired of it and I’m always afraid he’s gonna go too hard and hurt himself even more than he already does.