A device for converting electrical energy, including at least one switching-type semiconductor component, a cooling path for cooling the semiconductor component, and a device for determining a degradation of the cooling path based on a current having a predetermined current intensity that flows through the component. The device provides that the semiconductor component includes an optically active semiconductor material, which generates light having a brightness that is dependent on a temperature of the semiconductor component when the semiconductor component is traversed by current having a predetermined current intensity, and the device for determining the degradation includes a brightness sensor for recording the brightness of the generated light. The device has the advantage that the device for determining the degradation and the component are inherently galvanically isolated, and the degradation can be determined at a high resolution.