Development of a smart device for lead-acid batteries status analysis

Batteries are very important elements for the functioning of many devices, among which vehicles occupy a relevant spot. In this thesis work it is presented the development of a simple yet smart electronic device for 12V lead-acid batteries for automotive use. This after-market device, named BAT-up!, samples the voltage of the battery and is able to provide to the final user, thanks to a smartphone app, some useful informations such as the State Of Health and a new parameter named Time To Criticality. The first indicates the aging of the battery and is obtained by utilizing the open circuit voltage function, while the second is a time prediction of when the battery might be starting to work under a critical voltage threshold, and is obtained thanks to the reconstruction of the voltage profile with a RLS estimator. What this work was meant to accomplish was a significant step ahead in the industrial project already started by the company brain Technologies s.r.l., with the purpose of finalizing the local strategy and creating a working prototype that, with some future adjustments, could be put to market. In particular, the first steps were the definition of the functionalities and of a simplified version of the automotive V-cycle workflow. What followed was the build-up of the algorithm strategy and its model-based development in Simulink with concurrent Model-in-the-Loop tests. The basic software (firmware) needed by the target hardware to initialize the functionalities and schedule the various tasks, was generated starting from a prebuilt code for the BLE (Bluetooth Low Energy) transmission. The next step was the deployment of the model in the firmware, hence its integration in the hardware thanks to the auto-generated embedded code provided by Simulink. Subsequently, a simple setup allowed to perform some Hardware-in-the-loop tests on the integrated model, that indicated the need for reviewing it in order to perform some adjustments. A custom Android app was developed both to allow the receiving of the data sent by the device via BLE and to function as the Human-Machine-Interface with the user. At last, some tests were made on the field by connecting the device to a functioning battery of a car in order to simulate a realistic usage of the device. The results proved to be satisfactory and permitted the project to move forward in the development.