RECAP: Battery workflow evolution includes the development of electrochemical step to capture ion based chemical reactions in Abaqus. The step was later coupled with pore pressure step to capture the motion of fluid ions in the electrolyte due to interaction with the porous electrodes. On further evolution, the electrochemical pore pressure step was coupled with temperature displacement step to compute the temperature of chemical reactions and its structural response on the battery. This recaps till 2022xFD02.Aging Simulation: Like humans, batteries age as well. The rechargeable Li-Ion batteries have a lifespan of a few thousands of cycles. The main cause of ageing is the decomposition of electrolyte and its deposition on electrodes as solid electrolyte interface. This results in decrease in porosity and active surface area. Abaqus provides capabilities to model this kind of ageing in batteries. It does require additional material parameters to capture aging.
Aging is a very slow process and the charging discharging cycle need thousands of repeats to capture aging. New environment variables have been introduced to automate the repetitive process as its impractical to define thousands of steps in an input file. A typical battery cycle has 4 steps: charge: hold: free: discharge. Accordingly, a single input file with these four steps is created. Three environment variables are used as follows:
Os.environ[“ABA_STEP_CYCLING”]=N_repeat
Os.environ[“ABA_STEP_CYCLING_SPLIT”]=N_cycle_split
Os.environ[“ABA_STEP_CYCLING_OUTPUTFREQ”]=N_odb_output
First EV repeats simulation. Second EV splits the odb file at specified frequency. Third EV writes output data at specified frequency. 2023xFD04
Solid State Batteries: Solid state electrolyte batteries have an advantage. They are more compact with high energy densities. They can be easily transported. They have a lower risk of thermal runaway and fire. The underlying physics is diffusion and conduction. Conduction of electrons takes place in solid electrodes and diffusion of ions takes place in solid electrolyte. The charge transfer at the interface of electrolyte and electrodes is based on Butler-Volmer reactions. This model is invoked either by using surface based loading for shared nodes of electrodes and electrolytes or surface interaction property in case of dissimilar meshes.
*MULTIPHYSICS LOAD, TYPE=BUTLER-VOLMER
*INTERFACE REACTION, TYPE=BUTLER-VOLMER 2023xFD03
Expanded Outputs: New outputs are mainly for different types of heat fluxes. Surface heat flux due to Butler-Volmer reaction (ECHEMQS1), entropic heat generation at surface (ECHMQS2), volumetric heat generation (ECHEMQVi) etc. 2023xFD03
Element Support: Previous release included conventional stress and temperature-based elements to model regions that do not undergo electrochemical reaction such as solid parts other than electrodes. Additional element types in this release include DCOUPS, connectors, rigid bodies, UEL subroutine for user defined elements and progressive element activation. 2023xFD04
Leave a Reply