Battery Thermal Abuse Runaway Propagation Simulation Using Ansys Fluent
Welcome to this video on battery modeling with ANSYS Fluent. This video covers two models: one for a single cell and the other for a module.
Single Cell Model
The single cell is wrapped with a shell and has two tabs. Here's a walkthrough of the case outline tree:
General Settings
- This is a transient simulation.
- Gravity is turned off.
Models
- No fluid flow, so the viscous model is set to laminar.
- The energy equation is enabled by default when the battery model is turned on.
Battery Model
- Enabled using **CHD coupling**.
- Conductive zones include a cell and a nail inside the cell.
- Passive components include the tabs.
- Electric contacts: two terminals (negative and positive) at the top of each tab.
Model Parameters
- An energy source is applied at the nail, which is transient with levels of 250, 500, and 1000 watts.
- Thermal abuse model is turned on using the heat of short circuit (HEC) as a variable.
Materials
- No fluid is involved.
- Two solids:
- Active material for the cell with orthotropic thermal conductivity.
- Aluminum for the shell and tabs using default values.
Cell Zones
- Four different cell zones:
- Cell and nail specified with active material.
- Tabs and shell specified with aluminum.
Boundary Conditions
- All walls have a convective boundary condition.
- Bottom surface has a variable heat transfer coefficient driven by name selection, varying between 5 and 250.
- Remaining surfaces have a heat transfer coefficient of 5.
Methods and Controls
- Default values are used.
Report Definitions
- Tracking temperature and volume average temperature of the cell and nail.
- Monitoring and plotting these variables.
Module Model
The module consists of multiple cells sitting on a thermal pad atop a cold plate. Liquid water flows through the cold plate.
Initial Setup
- Started with a steady-state flow to generate fluid flow distribution with specified inlet temperature and flow rate.
- Switched to transient simulation for battery runaway.
Model Setup
- Similar setup to the single cell model with multiple cells and a nail.
- Includes passive components such as tabs and connecting tabs.
- Electric contacts for negative and positive terminals.
Model Parameters
- Nail specified with a heat source value; energy sources for cells set to zero.
- Battery thermal abuse model enabled with specified HEC value.
Materials
- Water flows in the cold plate, air zone surrounds the module.
- Active material for cells, air solid for air gap simulation.
- Aluminum for shell, tabs, and cold plate; copper for bus bars; plastic for end components; thermal pad material for thermal pad.
Cell Zone Conditions
- Fluid zones: air zone surrounds module; coolant flows through cold plate.
- Solids: copper for bus bars, aluminum for casing, active material for cells, aluminum for tabs and shells, plastic for end plastics, thermal pad material for thermal pad.
Boundary Conditions
- One inlet and two outlets (vent for air and coolant outlet).
- Walls have convective boundary conditions with specified heat transfer coefficients and free stream temperature.
- Air gap modeled with wall thickness and air solid material.
Named Expressions
- Air gap values: 0 and 2.
- Free stream temperature: 25°C.
- Coolant mass flow rate: 0.5 liters/second and 1 liter/minute.
- Coolant inlet temperature: 15°C and 25°C.
Report Definitions
- Focus on battery variable internal short for every cell and volume average temperature.
- Monitored with float report files and report plots.
This simulation was run for a period of 120 seconds.
Battery Thermal Abuse Runaway Propagation Simulation Using Ansys Fluent Hello and welcome to this video on battery modeling with ANSYS Fluent. This video covers two models: one for a single cell and the other for a module.
The single cell, shown on the screen, is a cell wrapped with a shell and has two tabs. Case Outline Tree: General tab: Transient simulation, gravity turned off. Models: No fluid flow, viscous set to laminar. Energy equation turned on by default when the battery model is turned on.
Battery Model: Enabled using CHD coupling. Conductive zones: cell, nail, passive components (tabs), electric contacts (two terminals: negative and positive). Model Parameters: Energy source at the nail, transient, three levels (250, 500, 1000 watts).
Thermal Abuse Runaway: Enabled, using heat of short circuit (H\_EC) as a variable. Materials: Solids (cell: active material, shell and tabs: aluminum). Cell Zones: Four zones (cell, nail, tabs, shell), specified with corresponding materials.
Boundary Conditions: Walls (external surfaces specified with convective boundary condition, bottom surface with variable heat transfer coefficient). Outside Example: Cells sit on a thermal pad, on top of a cold plate. Liquid water flows in, does a U-turn, and flows out.
Steady state simulation for fluid flow distribution, followed by a transient simulation for battery runaway. Materials: Water, air, aluminum, copper (for bus bars), plastic (end components), thermal pad material.
Cell Zone Conditions: Air zone for the air that surrounds the module, cell zone for the coolant that flows through the cold plate. Boundary Conditions: Inlet, outlet (coolant, vent for air), walls (casing, cells, tabs, cold plate, end plastics, thermal pad) with convective boundary condition.
Report Definitions: Battery variable internal short and volume average temperature, monitored with float report files and report plot. Simulation run for 120 seconds.
