Kroy Biermann was in a fit of rage when cops showed up after an explosive fight with Kim Zolciak ... where things got so bad, one of their kids called 911 to get some help.

In new police body cam footage -- obtained by TMZ from the incident on November 20 -- Kroy screams at officers his life with Kim is over. Officers try to get Kroy to calm down, but he continues on ... yelling about there being no money and no house.

At one point, Kroy calls Kim a total narcissist, and accuses her of manufacturing their drama. He's enraged, continuing to yell the couple's life is over ... and even accusing Kim of "f***ing other men." Eventually, officers calm Kroy down and get him inside to further talk things out.

The initial 911 call came in from one of the couple's 4 young kids who reported they believed Kroy had gotten physical with Kim ... but neither parent seems to give that claim any validity.

As for Kim, she's pretty hysterical as well ... sitting in her Range Rover as she explains her side of the story, claiming Kroy flew into a fit of rage and refused to let her leave the house. She says she began walking down the street in a robe and asking neighbors for help before returning back home.

Kim explains earlier in the day Kroy had asked her to sit and chat about their pending divorce. According to Kim, Kroy doesn't want to go forward with it -- even though he's the one who filed -- and Kim wants it to be finalized.

Through her sobbing, Kim claims Kroy's not the man she married, and believes he's mentally ill ... claiming she's scared at times to be around him.