TUBE CONNECTOR, THERMAL MANAGEMENT SYSTEM, BATTERY BOX, AND BATTERY

This application discloses a tube connector (30), a thermal management system, a battery box, and a battery. The tube connector (30) includes a body (300). A fluid channel (330) is formed inside the body (300). A first connecting portion (310) configured to be connected to the round tube (20) and a second connecting portion (320) configured to be connected to the flat tube (10) are formed on the body (300). The first connecting portion (310) is a hollow columnar structure (311). The second connecting portion (320) includes an oblong interface (321). A weld face (3211) that fits a shape of the flat tube (10) is formed on an inner sidewall of the interface (321).