A cooling module for an electric power converter, the cooling module comprising: - a housing, which has an external support face comprising means (54, 55) for fastening power conversion modules on the external support face, and - a heat transfer fluid network, the network comprising individual heat transfer fluid branches, deviated relative to one another, each branch extending in the housing in a network plane parallel to the external support face, each branch occupying an individual zone in the network plane, each branch comprising: - a heat transfer fluid supply collector, - a heat transfer fluid discharge collector, and - several individual heat transfer fluid sub-branches, each sub-branch: ∘ being connected to the supply collector via an inlet end of the sub-branch in question, ∘ being connected to the discharge collector via an outlet end of the sub-branch in question, ∘ occupying an individual sub-zone comprised in the zone of the branch in question, ∘ being deviated relative to the other sub-branches between the supply collector and the discharge collector, and ∘ forming a single heat transfer fluid channel that connects the inlet end to the outlet end, characterized in that the single channel of each sub-branch is formed, in the network plane, with an undulation having a regular pitch, and in that the single channel of each sub-branch comprises: - a first part, extending from the inlet end and being wound in a first spiral in the network plane, and - a second part, extending from the outlet end to the first part and being wound in a second spiral in the network plane, interleaved in the first spiral and in that each spiral, including the first spiral and the second spiral, is quadrilateral, defining four corners with each revolution. - a housing, which has an external support face comprising means (54, 55) for fastening power conversion modules on the external support face, and - a heat transfer fluid network, the network comprising individual heat transfer fluid branches, deviated relative to one another, each branch extending in the housing in a network plane parallel to the external support face, each branch occupying an individual zone in the network plane, - a heat transfer fluid supply collector, - a heat transfer fluid discharge collector, and - several individual heat transfer fluid sub-branches, each sub-branch: ∘ being connected to the supply collector via an inlet end of the sub-branch in question, ∘ being connected to the discharge collector via an outlet end of the sub-branch in question, ∘ occupying an individual sub-zone comprised in the zone of the branch in question, ∘ being deviated relative to the other sub-branches between the supply collector and the discharge collector, and ∘ forming a single heat transfer fluid channel that connects the inlet end to the outlet end, characterized in that the single channel of each sub-branch is formed, in the network plane, with an undulation having a regular pitch, and in that the single channel of each sub-branch comprises: - a first part, extending from the inlet end and being wound in a first spiral in the network plane, and - a second part, extending from the outlet end to the first part and being wound in a second spiral in the network plane, interleaved in the first spiral and in that each spiral, including the first spiral and the second spiral, is quadrilateral, defining four corners with each revolution. ∘ being connected to the supply collector via an inlet end of the sub-branch in question, ∘ being connected to the discharge collector via an outlet end of the sub-branch in question, ∘ occupying an individual sub-zone comprised in the zone of the branch in question, ∘ being deviated relative to the other sub-branches between the supply collector and the discharge collector, and ∘ forming a single heat transfer fluid channel that connects the inlet end to the outlet end, - a first part, extending from the inlet end and being wound in a first spiral in the network plane, and - a second part, extending from the outlet end to the first part and being wound in a second spiral in the network plane, interleaved in the first spiral