What faults can cause accidents where the motor (electric ball) group starts the motor and the transmission gear is toothed

Insufficient battery power and high battery temperature; The starter motor relay is not working; The transmission gear of the starter motor cannot mesh with the flywheel ring gear; The starter motor cannot rotate or rotates weakly when the diesel engine is engaged; The starting motor does not rotate; Startup failure; The diesel engine cannot be separated from the starter motor after operation.