Battery unit comprising cooling means

A battery unit comprising a plurality of rows of cells, longitudinal members having upper surfaces below a top of said cells positioned between said rows of cells, said longitudinal members being hollow, a receptacle receiving said plurality of rows of cells and said longitudinal members, and cooling means for cooling said cells, wherein said cooling means for cooling said cells comprises:

• a dielectric-fluid circulation circuit partially positioned at the bottom of the receptacle and at least partially bounded by the thickness of said longitudinal members,
• spray means for spraying said dielectric fluid onto said rows of cells, said spray means being positioned in the longitudinal members, said spray means passing through an upper surface of said longitudinal members and communicating with said circulation circuit,
• extraction means for extracting said sprayed dielectric fluid passing through said upper surface and opening into said circulation circuit, and
• a dielectric-fluid cooling circuit connected to said dielectric-fluid circulation circuit;
• wherein the cells are partially immersed in the dielectric-fluid circulation circuit, and wherein the cooling circuit comprises a cooling device for cooling the dielectric fluid and pressurizing means for pressurizing said dielectric fluid, said pressurizing means comprising:
• a low pressure pump adapted to pressurize the dielectric fluid at a pressure sufficiently low to avoid spraying of said dielectric fluid, and
• a high pressure pump adapted to pressurize the dielectric fluid at a pressure sufficiently high to cause said dielectric fluid to spray through said spray means;
• wherein the high-pressure pump is distinct from said low-pressure pump;
• said pressurizing means further including a bypass operable to bypass said high-pressure pump during said first driving situation;
• and,
• wherein said battery unit is positioned in a vehicle, and wherein, when the vehicle is in a first driving situation which does not require rapid cooling, said high-pressure pump is not active, such that spraying of said dielectric fluid is avoided and when the vehicle is in a second driving situation which requires additional cooling, said high-pressure pump is activated to provide additional cooling to said battery unit.