The gap between the battery cover and the middle frame of the Redmi 13 is a special design.
For your reference, here is some information regarding this design below:
1. The battery cover is made of glass, and the design includes a special gap that allows the frame to absorb some of the impact when the phone is subjected to side impacts. This prevents the glass battery cover from breaking;
2. The product process results in a visually large gap, however, the glass battery cover is sealed to prevent dust and water ingress. The product undergoes all relevant inspections before leaving the factory. Please feel free to use it.