BATTERY BOX

The present invention provides a battery box, which includes a lower box body (1), where the lower box body includes a first plate (11) and a second plate (12). The first plate (11) includes: a bottom wall (111); the second plate (12) is fixed to the bottom wall (111) from a bottom and engages with the bottom wall (111) to form a flow passage (F). The second plate (12) is provided with: a second protrusion (121) protruding to the first plate (11); and an opening (122) running through the second protrusion (121) in a height direction (H), the second protrusion (121) of the second plate (12) being connected to the bottom wall (111) of the first plate (11) in a sealed manner. The battery box further includes: a reinforcing beam (2) provided under the second plate (12); the reinforcing beam (2) is mounted at a position corresponding to the opening (122) and is fixedly connected to the first plate (11) and/or the second plate (12). A setting of the reinforcing beam (2) improves structural strength of the lower box body (1), and avoids risk of easy damage of the lower box body (1) at a position with weak structural strength.