Cooling of Electronic Components

Heat is generated in many electrical and electronic components when in use, which must be dissipated to the environment to ensure optimum operating temperatures (e.g. in LEDs, processors, power converters, batteries). Exceeding the operating temperature range often leads to accelerated component aging or to a loss of performance or even failure. Heat is generated by the resistance of current-carrying conductors (Joule heat) or as a result of changing electrical fields (induction heat).

The thermal design of passive or active thermal management systems for heat-generating electronic components requires various steps, including

• the determination of the temporal and local intensity of the heat sources within the component,
• the optimization of heat transport properties of individual materials or the minimization of thermal contact resistances and
• the development of active or passive cooling systems to buffer thermal load peaks and to transfer heat to the environment.     

Fraunhofer IFAM Dresden offers you all these competences from one hand, starting with thermal system analysis, determination and optimization of material properties, design and implementation of cooling systems to their experimental validation.

For the development of thermal management systems for heat-generating electronic assemblies, Fraunhofer IFAM Dresden offers a wide range of expertise in

• development of composite materials (e.g. metal-carbon composites) with excellent thermal conductivity,
• development of composite materials from cellular metals and phase change materials (PCM) with tailor-made storage capacity and performance for thermal buffering, 
• production of microcoolers and heat sink structures by additive manufacturing.

Based on the results of the heat source analysis, mathematical simulations are carried out to calculate the unsteady, multi-dimensional temperature fields in the components, which can be used to specify the material and thermal engineering requirements for suitable temperature control systems.

On this basis, individual components of temperature control systems can be developed, prototypically manufactured and experimentally validated in our thermo-technical laboratory. For application-oriented tests of the temperature control systems, real heat sources are used or simulated by electrical heat sources with regard to their local and temporal behaviour.

Depending on the type of galvanic cell system, thermal management is of enormous importance for safe, efficient and long-lasting battery operation, especially in electrochemical storage systems. In addition to warming up during a cold start, Joule heat must constantly be dissipated in accordance with the electrical load profile, especially in the case of power storage units.

Fraunhofer IFAM Dresden has been working successfully for years on the development of latent heat buffer structures for batteries to absorb thermal peak loads. Within these composite materials,

• cellular metal structures (fibres, foams) take over the task of heat transport in/from the heat buffer (flexible performance) and
• a phase change material (PCM, e.g. paraffin) takes over the task of the heat storage (high capacity).

These composite materials can be combined with active cooling systems, but ideally they can also make these unnecessary if the lower average power can be dissipated by a passive cooling system due to the heat buffers.

For the design of such thermal management systems we offer expertise in

• the analysis of heat source densities in battery cells,
• the determination of material data (thermal conductivity, heat capacity),
• the derivation of required properties of composite material systems from mathematical simulations,
• material and system development and
• the experimental validation of buffer and cooling systems in our thermo-technical laboratory.