The main objective of the “KOBIBATT“ project is to develop a battery system with higher energy density and greater safety at lower costs. In battery research, these goals have so far been seen as contradictory and incompatible. For the first time, “KOBIBATT“ addresses all three goals simultaneously. The central challenges are as follows: (1) the development of an innovative and fully welded polymer-based bipolar battery, (2) research into a constructive design, (3) the development of cost- and resource-efficient roll-to-roll manufacturing and joining processes. The design for the bipolar battery will be developed and demonstrated using a high-energy-density lithium ion bipolar battery for mobile applications and a long-life nickel-iron bipolar battery with cycle stability for stationary applications.
The technical challenges of the project are the development of electrochemically stable, resource-saving and cost-effective bipolar electrodes and their assembly into perfectly sealed battery stacks. The innovative project approach pursued by the participating researchers aims to develop weldable, highly conductive polymer-based bipolar films that are produced in one process with polymer solid-state electrolytes and composite electrodes and welded together to form a complete battery.
The structure and manufacturing process of current battery systems are highly complex. In the past, a battery system required the interconnection of many individual cells with low power, which resulted in low energy density due to the large number of inactive envelope components. High material consumption and difficult-to-automate single-cell assembling (assembly of the different components) are further disadvantages of current battery systems. In order to further increase the energy density, considerably larger individual cells would have to be used, which, however, increase the risk of hot spot formation at connectors and conductors and thus the risk of fire due to the high current load.