Battery pack

A battery pack comprising:

• a battery assembly including a plurality of batteries;
• a fluid drive member that drives fluid cooling the battery assembly;
• a housing housing the battery assembly and the fluid drive member;
• a circulation passage defined in the housing to form a series of flow channels for the fluid flowing out of the fluid drive member to flow back into the fluid drive member after exchanging heat with the batteries;
• and
• a plurality of beams disposed integrally with a bottom wall of the housing to support the battery assembly from a lower side, wherein
• the circulation passage includes
• a first fluid passage defined between the battery assembly and a wall of the housing that is a heat dissipation portion which dissipates heat to an outside of the housing through a contact with the fluid flowing out of the fluid drive member,
• a battery passage defined between the batteries adjacent to each other in the battery assembly, and
• a second fluid passage downstream of the battery passage and extending toward an inflow portion of the fluid drive member,
• the first fluid passage, the battery passage, and the second fluid passage are a series of passages provided for the fluid flowing through the first fluid passage to flow into the second fluid passage by passing through the battery passage,
• the second fluid passage is surrounded by at least the beams, the bottom wall, and a lower end of the battery assembly,
• the second fluid passage is one of two second fluid passages defined on respective sides of one of the plurality of beams,
• the one of the plurality of beams has a through hole that defines a communication passage connecting the two second fluid passages with each other,
• the fluid drive member has an outlet port positioned in a side wall passage of the first fluid passage defined between the battery assembly and a first side wall of the housing adjacent to the bottom wall,
• the housing has a top wall,
• the first side wall is adjacent to the top wall and to the bottom wall,
• the housing further has a second side wall adjacent to the top wall and the bottom wall and perpendicular to the first side wall,
• the first fluid passage further has a top wall passage defined between the side wall passage and the battery passage in a flow direction of the fluid,
• the side wall passage is defined by between the battery assembly and the first side wall to extend parallel to the first side wall,
• the outlet port of the fluid drive member is adjacent to a battery of the plurality of batteries that is closest to the second side wall, and
• the battery pack further includes:
• a first internal fin protruding from an inner side of the second side wall;
• a second internal fin protruding from an inner side of the top wall;
• and
• an external fin disposed on an outer side of the second side wall at a position corresponding to the first internal fin.