Mr.
Topic(s) : Multifunctional and smart composites
Co-authors :
Johannes KÜHN (GERMANY), Robert SEIDEL-GREIF (GERMANY), Willi ZSCHIEBSCH (GERMANY), Thomas ABENDROTH , Thomas BEHNISCH (GERMANY), Stefan KASKEL , Robert BÖHM (GERMANY)Abstract :
The development of more efficient energy storage systems is required by the high demand for electrification in the transportation sector. However, the total amount of energy stored per system mass is a key factor for their efficiency. The strategy of material and mass saving by replacing structural passive materials at the system level (i.e.: airplane interior or hull) with multifunctional composites at the cell level (i.e.: fiber-reinforced anode), seems to be promising.1 For the idea of such a structural energy storage the integration would refer to the integration of materials with considerable mechanical as well as energy storage
capabilities. A potential candidate has been found in PAN-based carbon fibers as anode material in lithium-ion batteries, showing energy storage and excellent mechanical properties.2,3,4
However, there is still a lack of consideration with respect to manufacturing processes and concepts of fiber integration based on standard battery manufacturing processes.
This contribution focuses on the integration of continuous fiber-based composites into standard battery manufacturing processes like wet film coating. Therefore, a lithium-ion battery reference pouch cell was fabricated with standard battery materials and characterized with respect to mass balance, storage capability (i.e.: rate-test and long-term cycling) and mechanical properties (i.e.: tension and bending test). The results allowed the identification of anode and packaging as major contributor to the mechanical properties
as well as passive mass. Therefore, the first concept included electrode manufacturing processes to manufacture fiber-based anode composites. The obtained composites were then compared with standard battery anode materials such as graphite and hard carbon with respect to mechanical and electrochemical properties to identify further optimization needs. A modification of the charge and discharge protocol by addition of a constant capacity and a constant voltage step after discharge allowed the utilization of additional
capacity. The combination of standard materials with fibers in hybrid structures were found to be a further promising optimization.
As a second concept, the fiber integration targets the passive structure of the battery packaging, previously identified by the mechanical tests and mass balance of the reference system. The use of commercial carbon-reinforced-polymers is considered for the use as cell packaging material and will be tested.
In general, the process of fiber integration is investigated starting from the reference system of a lithiumion pouch cell. The integration is continued towards the composite processing in order to achieve an integration into active as well as passive battery compounds.
capabilities. A potential candidate has been found in PAN-based carbon fibers as anode material in lithium-ion batteries, showing energy storage and excellent mechanical properties.2,3,4
However, there is still a lack of consideration with respect to manufacturing processes and concepts of fiber integration based on standard battery manufacturing processes.
This contribution focuses on the integration of continuous fiber-based composites into standard battery manufacturing processes like wet film coating. Therefore, a lithium-ion battery reference pouch cell was fabricated with standard battery materials and characterized with respect to mass balance, storage capability (i.e.: rate-test and long-term cycling) and mechanical properties (i.e.: tension and bending test). The results allowed the identification of anode and packaging as major contributor to the mechanical properties
as well as passive mass. Therefore, the first concept included electrode manufacturing processes to manufacture fiber-based anode composites. The obtained composites were then compared with standard battery anode materials such as graphite and hard carbon with respect to mechanical and electrochemical properties to identify further optimization needs. A modification of the charge and discharge protocol by addition of a constant capacity and a constant voltage step after discharge allowed the utilization of additional
capacity. The combination of standard materials with fibers in hybrid structures were found to be a further promising optimization.
As a second concept, the fiber integration targets the passive structure of the battery packaging, previously identified by the mechanical tests and mass balance of the reference system. The use of commercial carbon-reinforced-polymers is considered for the use as cell packaging material and will be tested.
In general, the process of fiber integration is investigated starting from the reference system of a lithiumion pouch cell. The integration is continued towards the composite processing in order to achieve an integration into active as well as passive battery compounds.