In BEV the technical progress is driven by the performance and reliability of traction batteries. Customers’ demands for long ranges and performance are leading to a steady increase in the energy density of battery cells. Since the active materials are performance and lifetime determining and most valuable components of a single battery cell, most development effort is put on them. However, the electrochemical processes remain sensitive to temperature and aging, e.g. Lithium-plating or stress induced aging. Thus, it seems insufficient for future applications to rely only on the status-quo determination of temperature on selected cells.
Consequences are the risk of a delayed detection of thermal runaway, of which the severity increases with a cell’s energy density, as well as the unknowledge of a single cell’s residual capacity or remaining useful lifetime. Thus, reducing a cell’s, module’s or even pack’s residual value for a 2nd life scenario.
These issues are addressed by governmental regulations that require passenger’s security by early detection of TR. Further EU regulations might ask for a cell-individualised fingerprint, the battery pass. It aims to proof a cell’s originality and to preserve the active materials either by prolonging its overall lifetime, e.g. 2nd use, or by recycling.
Although cell-based monitoring offers enormous added value for the cell, there is currently no production-ready wireless solution on the market.
Thus, HOERBIGER, an engineering partner and system supplier for prismatic cell housings and cell lids, is developing a cell housing with highly integrated sensors and electronics. This contribution provides an overview of the various status variables and sensors that are considered for use. It discusses various approaches for sensor integration and the resulting benefits of the diagnostic functions and its meaning for the cell reliability. Ultimately, an insight is given into the requirements for the interface between mechanics and electronics that must be fulfilled for automotive application.