Industrial application of thermofluid topology optimization to rollbonding cold plates with dedicated manufacturing constraints

The transition of the automotive industry towards electro-mobility is highly dependent on the performance of batteries. Those batteries need a temperature management system, often realized as sheet metal cold plates with integrated channel structures for liquid cooling. Rollbonding technology is one of the most promising methods for industrial mass production of battery cooling systems in the automotive industry due to its competitive cost for low and high-volume applications and its great degree of design freedom. Designing cold plates is a challenging task due to conflicting thermal and hydraulic objectives, manufacturing requirements and the enormous design freedom offered by the rollbondig technology. Topology optimization is a well-known method for optimal design in multi-physics problems, such as cold plate design. Using a thermofluid topology optimization, the optimum channel patterns in a given design space can be found. However, the industrial application of such a design approach is challenging, as well-established topology optimization software often is designed for a wide variety of applications and, therefore, lacks manufacturing constraints and parametrization strategies feasible for the specific production process. This paper demonstrates how well-known parametrization and optimization strategies can be combined and adapted to generate topologies feasible for the manufacturing of cold plates by rollbonding. The integration of commercial solvers into an external, solver agnostic framework, considering custom manufacturing, continuation and filtering strategies is demonstrated. A density-based topology optimization is applied to the linear potential Darcy flow model, considering length scale constraints on the solid and fluid domain. A specific constraint is developed to assure the manufacturability of the design using the rollbonding technology. Further, a feasible continuation strategy considering projection parameters, penalization and length scale constraint activation and continuation is presented. The temperature distribution is optimized while considering pressure drop and manufacturing requirements. The topology optimization results are remodeled and validated using a high-fidelity RANS solver. The thermal-hydraulic performance is compared with a manually designed benchmark cold plate. Finally manufacturability of the outcomes is evaluated to prove the successful application of the proposed design technology.