TY - THES

T1 - Material Development and Modelling of a Thermal Insulation Film in Battery Systems

AU - Petersmann, Sandra

N1 - embargoed until 08-08-2023

PY - 2018

Y1 - 2018

N2 - The thermal management of battery systems is becoming increasingly important with the gaining demand of electric vehicles. Nonetheless, no convincing solutions for thermal insulation foils are able to avoid thermally initiated chain reactions between adjacent battery modules in the event of thermal runaway. Therefore, the aim is to develop an innovative thermal insulation membrane. The main idea is to design a material exhibiting decreasing thermal conductivity properties with increasing temperatures. This material behaviour is caused by expandable flake graphite, a form of intercalated graphite. Due to the expansion process, the free volume increases resulting in a reduced thermal conductivity of the material. The expansion of the utilized flake graphite is starting at temperatures around 150°C. The flakes and further additives are embedded into a dual-component silicone resin. During the product development, a number of different material tests are performed in order to characterize the material behaviour at different conditions. Evaluation of the thermal stability of the insulating foil is of paramount importance in the design process. Furthermore, uniaxial tensile and compression as well as biaxial tensile tests are conducted with different mid-layer configurations of the insulation composite to analyse the influence of different fillers. Additionally, the test data is made use of to determine the parameters of known hyperelastic material models for the matrix material. Uniaxial compression tests in addition to the standard uniaxial tensile tests are performed as the insulating layers primarily absorb compressive loads.

AB - The thermal management of battery systems is becoming increasingly important with the gaining demand of electric vehicles. Nonetheless, no convincing solutions for thermal insulation foils are able to avoid thermally initiated chain reactions between adjacent battery modules in the event of thermal runaway. Therefore, the aim is to develop an innovative thermal insulation membrane. The main idea is to design a material exhibiting decreasing thermal conductivity properties with increasing temperatures. This material behaviour is caused by expandable flake graphite, a form of intercalated graphite. Due to the expansion process, the free volume increases resulting in a reduced thermal conductivity of the material. The expansion of the utilized flake graphite is starting at temperatures around 150°C. The flakes and further additives are embedded into a dual-component silicone resin. During the product development, a number of different material tests are performed in order to characterize the material behaviour at different conditions. Evaluation of the thermal stability of the insulating foil is of paramount importance in the design process. Furthermore, uniaxial tensile and compression as well as biaxial tensile tests are conducted with different mid-layer configurations of the insulation composite to analyse the influence of different fillers. Additionally, the test data is made use of to determine the parameters of known hyperelastic material models for the matrix material. Uniaxial compression tests in addition to the standard uniaxial tensile tests are performed as the insulating layers primarily absorb compressive loads.

KW - material development

KW - material modelling

KW - material characterisation

KW - battery systems

KW - hyperelasticity

KW - hyperelastic material models

KW - insulation film

KW - tensile test

KW - compression test

KW - bulge test

KW - biaxial tensile test

KW - thermal conductivity

KW - expandable flake graphite

KW - intercalation

KW - silicon resin

KW - mica paper

KW - Materialentwicklung

KW - Materialmodellierung

KW - Materialcharakterisierung

KW - Batteriesysteme

KW - Hyperelastizität

KW - hyperelastische Materialmodelle

KW - Isolationsschicht

KW - Zugversuch

KW - Druckversuch

KW - Bulgeversuch

KW - biaxiale Zugversuche

KW - Wärmeleitfähigkeit

KW - Blähgraphit

KW - Interkalation

KW - Silikonharz

KW - Micapapier

M3 - Master's Thesis

ER -