Box body assembly and battery pack

A battery pack comprising

• a battery module;
• a box body assembly configured for accommodating the battery module, comprising:
• a box body comprising a first cooling plate and a second cooling plate arranged opposite to each other, and first side plates connected between the first cooling plate and the second cooling plate;
• the first side plates comprising side edges arranged opposite to each other;
• and
• liquid cooling joint groups comprising a first liquid cooling joint and a second liquid cooling joint;
• the first liquid cooling joint being connected to the first cooling plate;
• the second liquid cooling joint comprising a first transition section, a second transition section, and a third transition section;
• the first transition section being connected to the second cooling plate, both the second transition section and the third transition section being connected to the first transition section;
• the second transition section being configured to connect an external liquid cooling structure;
• the third transition section and the second transition section being arranged to extend in directions facing away from each other and in communication with the first liquid cooling joint;
• a distance between an orthographic projection of the first liquid cooling joint on a plane where the second cooling plate is located and an orthographic projection of the first transition section on the plane where the second cooling plate is located being D1;
• a distance from the first transition section to the side edges being D2, and D2 being greater than D1;
• a mounting space being formed in a box body;
• the battery module being arranged in the mounting space;
• and a second cooling plate being located on a bottom of the battery module.