Lithium-ion batteries are efficient energy storage devices used in many different applications. For a long time now, rechargeable lithium-ion batteries have been used in a multitude of electronic con-sumer goods such as mobile phones, laptop, etc. In recent years this technology has been increasingly used in the car industry as well. One challenge for this type of battery is the need to enhance the life span of the battery cells. This depends very much on the temperature at which the cells operate. Even short periods above the rated operating temperature –sometimes just localized overheating –can damage the cell irreversibly. Cooling the battery cells is thus an important factor which can have a positive effect on extending the useful life of the battery. In the opposite situation – during a cold start – batteries often have too little power. If a certain amount of power is required as soon as the vehicle starts, the battery needs to be heated in advance. The heating unit must be designed and operated in such a way that the whole battery reaches the required minimum temperature in a specific time, while ensuring that no temperature peaks occur which could damage the cells. To avoid having to carry out extensive and costly experiments, our customer wanted a thermal simulation model of a battery system with which he could investigate the relevant scenarios for himself. This needed to be embedded in a larger simulation model. A further challenge lay in the fact that the end users of the simulation routine should not be able to change the content. Our project strategy:
- A thermal model (heat flow in the cells, convection in the coolant, heat sources in the cells and HV components) of the battery system which was validated with the customer’s own measurement data;
- Programming of the differential equation system in MATLAB/ Simulink;
- Compilation of the Simulink block with the Real-Time Workshop;
- Presentation and instructing the customer in the use of the model.
The customer now has a model with which he can simulate and thermally evaluate all situations which can arise. Do you have any similar problems? Get in touch with us without obligation – we will be pleased to help you! Please send an e-mail to email@example.com