Heat Exchanger for an Internal Combustion Engine, Having a Stiffening Element in the Region of a Join Between Two Partitions, and Internal Combustion Engine Having a Heat Exchanger

A heat exchanger for an internal combustion engine transfers heat between fluids, and includes a housing which has a housing wall and a housing interior that is bounded at least in certain regions by the housing wall. The housing interior has a fluid inlet region for the introduction of a first of the fluids into the housing interior, and a fluid outlet region for discharging the first fluid from the housing interior. The heat exchanger has at least two partitions which are at least predominantly accommodated in the housing interior and which are connected to the wall of the housing at at least one connection region. In order to separate the fluids from one another, the partitions bound, at least in certain regions, a fluid receiving space through which a second of the fluids can be made to flow. The partitions are connected to one another at least at a joining region that is assigned to the fluid inlet region and that adjoins the fluid receiving space in a main flow direction of the first fluid. The heat exchanger additionally has a stiffening element which, in order to stiffen a stiffening portion of the joining region adjoining the connection region, is arranged at the joining region and is configured to brace the stiffening portion at least against a buckling load arising from a change in length in the event of a temperature-induced change in length of the joining region.