Electrothermal and 3D Thermal Model for Lithium Ion Capacitors

摘要

ULTIMO Lithium ion capacitors (LiCs) produced by JM Energy, a sister company of JSR Micro NV, are one of the emerging and innovative technologies in the field of energy storage. Their high power capability, high energy density, long cycle life (more than 2 Million cycles) and wide operating temperature (-30?C to 70?C) make them very unique. They combine the advantages of both traditional electric double layer capacitors (EDLCs) and lithium ion batteries (LiBs). For many customers and producers of energy storage systems, it is mandatory to have a reliable model which is capable of predicting the cell's behavior in different applications. A pure electrical model alone cannot meet the expected accuracy as most parameters in the LIC cells are temperature dependent. Other factors, such as current level and cell aging, impact the behavior of LiCs. As a result, a comprehensive electrothermal model which takes the aging effect into account is required. In industrial applications, LiCs are generally integrated in closed case modules. An accurate 3D thermal model, capable of predicting the surface cell temperature, is therefore crucial. Having a precise thermal model at module level also helps in sizing the adequate cooling system. JSR Micro NV, together with Vrije Universiteit Brussel (VUB), have developed such a highly accurate tool for both cell and module modelling. In the following sections, these models are presented and explained. The accuracy is verified and validated through experimental tests.