Creating the Layers Structure
Once the modeling scale is selected, the structure of the battery internal layers can be created by providing the following:
Layers dimensions and origin:
Y and Z dimensions, and origin which can be defined either as a node or in 3 dimensional coordinates.
Layers meshing:
The meshing can be applied by defining either the number or the size of the elements in each direction. For the Micro and Meso scales, the number of elements in the X direction is restricted to a single element, while for the Macro scale, any number of elements can be used.
Layers repetition:
The Number of layers per unit cell is only applicable to the Meso structure and can be set to any number. For the Micro structure, this is restricted to 5 layers, while for the Macro structure the layers are not explicitly modelled by individual parts.
For all modeling scales, Multiple repetitions of the unit cell can be created in both X and Y directions. Repetitions in the X direction will have the same Y and Z origin as the first copy but the X origin of every new copy will be offset by the full thickness of the unit cell plus the Separation between repetitions in the -X direction. Repetitions in the Y direction will be reflected as copies of the unit cell rows in the +Y direction with also a controllable separation value.
If Use common *SECTIONs is turned on, then a common section will be created for identical parts in all unit cell copies (for example for the Micro scale, all parts representing the positive current collector layer will use the same *SECTION). Otherwise, each part created by the tool will have a unique *SECTION.
Material and thickness:
For Micro and Meso scales: The Structural Material id, Thermal Material id and Thickness of each of the 5 layer types must be defined. The layer type currently being edited will be highlighted, and you will only be able to set the values for a given layer type once this is completed for all layers preceding it. Note that the structural material needs to be unique for each layer type as an *EM_MAT_001 card will automatically be generated by default to define the electromagnetic type and properties of the selected material. The Initial conductivity can be defined for the current collector layers (PCC and NCC) and will be reflected in the assigned *EM_MAT_001 (SIGMA field). The initial conductivity for the other 3 layers is forced to be zero as these are non-conductive. If you don't want PRIMER to automatically create any *EM_MAT cards you can turn off the Auto-create *EM_MAT cards option.
The MTYPE, SIGMA and RDLTYPE fields in the generated *EM_MAT_001 cards will take the following values:
| Layer type | MTYPE | SIGMA | RDLTYPE |
|---|---|---|---|
| PCC | 2: Conductor carrying a source | Initial conductivity (set by user) | 1 |
| CATHODE | 1: Insulator | 0 | 2 |
| SEPARATOR | 1: Insulator | 0 | 3 |
| ANODE | 1: Insulator | 0 | 4 |
| NCC | 2: Conductor carrying a source | Initial conductivity (set by user) | 5 |
All other fields are set to their defaults.
For Macro and Meshless connected to Macro scales: The Structural Material id, Thermal Material id and Thickness of the whole unit cell must be defined. Note that the structural material must not be previously associated to an *EM_MAT instance as this will automatically be generated by the tool to define the electromagnetic type and properties of the selected material. If it is already associated, then the tool will not create a new *EM_MAT_006 instance and the existing one will be used. The Positive Initial conductivity and Negative Initial conductivity can be defined for the unit cell and will be reflected in the assigned *EM_MAT_006 (SIGP and SIGN fields).
| MTYPE | SIGP | SIGN | |
|---|---|---|---|
| Unit cell | 5: Material associated to *EM_RANDLES_BATMAC | Positive conductivity (set by user) | Negative conductivity (set by user) |
All other fields are set to their defaults.
Once all values are provided, clicking on Create will generate the layers parts and associated entities.
For the Micro scale: 5 solid *PARTs will be meshed per unit cell representing the 5 layers
For the Meso scale: a *PART_COMPOSITE_TSHELL will be meshed per unit cell with the number of layers selected. The layers will be added in the following sequence: PCC - Cathode - Separator - Anode - NCC - Anode - Separator - Cathode - PCC - Cathode - Separator ...
For the Macro scale, and Meshless connected to Macro scale: a single solid *PART will be meshed per unit cell.
If you wish to make any modifications to the layers structure once created, click on the Edit button to delete all the created layers structure entities, update the parameters as desired and click on Create again to rebuild the structure. Note that clicking on Edit will also delete any entities created during the '3. Tabs structure' and '4. Randles parameters' stages as these are dependent on some of the entities created during the '2. Layers structure' stage.
Once satisfied with the layers structure, you can move to the '3. Tabs structure' step by either clicking on the corresponding button at the top of the window, or using the Next button. You can also move back to previous stages using the Previous button.
