(Best Poster Award - 3rd Place) Development of Bipolar All-Solid-State Lithium-Ion Cell

Abstract

For large-scale electricity storage applications such as automotive and stationary energy storage, the battery system requires a high voltage and energy density, which can be achieved by bipolar architectures. In conventional batteries, the cells are assembled in series. The amount of current collector and packaging substances (case, wires) increases the battery weight, reducing its energy density, and complicates the manufacturing. The switch to bipolar technology simplifies the cell architecture. The cathode and anode material layers are separately coated on both sides on a same current collector. This gives to the creation of electrolyte-separated units. External connectors are no longer necessary as the electron transfer between the two electrodes is through the current collector. As a result, the ohmic resistance is reduced and less heat is generated. The bipolar architecture leads to a simple and compact design for a high specific energy and a high-voltage and current output for a high specific power.Over the 15 past years, CEA developed an expertise on bipolar lithium-ion batteries1. However, the development of bipolar cells with liquid electrolyte has been rather limited in industrial applications due to electrolyte leakage: it is imperative to avoid liquid junction and to prevent the ion flow between each adjacent unit. The use of solid- electrolyte appears as the optimal solution and simplifies the manufacturing process and reduces cost2.Astrabat project focused on all-solid-state lithium-ion batteries and the development of two tailored polymer electrolytes. These results are transferred and adapted to a bipolar architecture, composed of two units. The silicon anode and Ni-rich NMC cathodes are coated on an Al/Cu clad, serving as a current collector. This work will report the fabrication process and the electrochemical performances of the two-units bipolar architecture. 1M. Chami, S. Mailley, Y. Reynier, F. Masse, S. Martinet and F. Fusalba, World Electric Vehicle Journal Vol. 3 - ISSN 2032-6653 2 H.-S. Shin, W.-G. Ryu, M.-S. Park, K.-N. Jung, H. Kim and J.-W. Lee, ChemSusChem 2018, 11, 3184 – 3190 Figure 1