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, active materials reflect the historic significance of extreme C-rates and temperatures, also called aging. Considering manufacturing fluctuations and the different situations (sorting, storage, operation, logistics) in which the condition of batteries is to be determined, it seems insufficient to keep track only when cells are connected to a battery pack controller. Additional need for improved measuring precision especially for batteries approaching end of life stems from battery-module architectures possessing distributed temperature measuring points. Consequences are the risk of a delayed detection of a thermal runaway, as well as the unknowledge of individual aged cell’s thermal condition during charging and discharging. Thus, reducing a cell’s, module’s or even pack’s remaining useful lifetime or residual value for a 2nd life scenario.
These issues are addressed by governmental regulations that require passenger’s security by early detection of a thermal runaway. Further EU regulations might ask for a cell-individualized 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.
These requirements are met by a cell-based monitor integrated in the cell lid, while it enables more precise measure of each cell’s condition at different points during the lifecycle. Though, there is currently no cell lid with highly integrated wireless cell monitor on the market, that is suitable for series-production.
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 functions and sensors that are provided and outlines various benefits for the stakeholders along the battery life-cycle. For integration, two different approaches are demonstrated, which suit the given requirements.