Electric power conversion unit for improving cooling efficiency

An electric power conversion unit comprising:

• a first housing;
• a fluid machine that generates a flow of a refrigerant at an inside of the first housing;
• a heat release member that forms a flow path of the refrigerant on an upstream side of a flow route of the refrigerant at the inside of the first housing;
• a plurality of first elements in which the first elements are arranged and aligned along a direction which intersects a flow direction of the refrigerant in the heat release member on an element arrangement plane of the heat release member;
• a plurality of second elements in which the second elements are arranged on a further downstream side than the plurality of first elements in the flow route;
• and
• a second housing that supports the plurality of second elements so as to cause the refrigerant to flow between adjacent second elements,
• wherein the second housing includes:
• an upper portion having a plate shape and having insertion holes in which the second elements are individually inserted,
• a support member having a plate shape and on which the second elements are provided,
• a plurality of upper openings through which the refrigerant passes, the upper openings being formed between the insertion holes in the upper portion, and
• a plurality of support portion openings through which the refrigerant passes, the support portion openings being formed at positions that avoid the second elements of the support member.