A baffle unit includes an inner ring, an outer ring disposed outside the inner ring, and a connecting portion connecting the inner ring with the outer ring. The connecting portion includes multiple openings arranged in a radial direction of the baffle unit and in a circumferential direction of the baffle unit, each of the multiple openings being arcuate and extending in the circumferential direction; multiple rigid portions each being disposed between the adjacent openings of the multiple openings that are adjacent to each other on a same concentric circle of the baffle unit; and multiple walls each being formed between the adjacent openings of the multiple openings that are adjacent to each other in the radial direction. Each of the multiple walls connects a rigid portion of the multiple rigid portions with another rigid portion of the multiple rigid portions.