Battery Geometries

We support multidimensional geometries (from 1D to 3D). The geometry is part of the input data and must be setup up before a simulation. The base class BatteryGenerator provides a template to construct the battery geometry, which includes a mesh for all the components (Coatings, sepators, current collectors…) and the coupling between those as the main output.

To create our grids, we rely essentially on the grid generation functions provided by MRST. We use also the visualization tools available there, see here.

Standard geometries can often be parameterized, meaning that a small set parameters is enough to construct the whole geometrical model. We have implemented some standard geometries and provide here examples with an illustration and a list of the parameters used to produce this illustration. The parameters can be passed through json interface and aref described in some more detail in the geometry json schema.

BatteryGeneratorP2D

The geometrical model is 1D. Here, for the sake of the illustration, we plot a corresponding 3D model.

Parameters with values used in plot above

Parameter	Name	Value
length of negative current collector	x(1)	25 μm
length of negative active material	x(2)	64 μm
length of separator	x(3)	15 μm
length of positive active material	x(4)	57 μm
length of positive current collector	x(5)	15 μm
discretization number for negative current collector	ccnen	10
discretization number for negative active material	nenx	10
discretization number for separator	sepnx	10
discretization number for positive current collector	penx	10
discretization number for positive active material	ccpenx	10
Face area	faceArea	3 cm^2

BatteryGeneratorP3D

The geometrical model is 2D.

Parameters with values used in plot above

Parameter	Name	Default value
length of negative current collector	xlength(1)	10 μm
length of negative active material	xlength(2)	100 μm
length of separator	xlength(3)	50 μm
length of positive active material	xlength(4)	80 μm
length of positive current collector	xlength(5)	10 μm
length in y direction	ylength	1 cm
discretization number for negative current collector	ccnenx	10
discretization number for negative active material	nenx	10
discretization number for separator	sepnx	10
discretization number for positive current collector	penx	10
discretization number for positive active material	ccpenx	10
discretization number in y direction	ny	10

BatteryGeneratorP4D

A 3D geometrical model consising only of one layer with one tab on each current collector.

An illustration with different scalings for each axes which shows the different component:

Parameters with values used in plot above

Parameter	Name	Default value
x-length of first tab	x(1)	4 cm
x-length between the tabs	x(2)	2 cm
x-length of last tab	x(3)	4cm
y-length of first tab	y(1)	1mn
y-length between the tabs	y(2)	2 cm
y-length of last tab	y(3)	1 mm
length of negative current collector	z(1)	10 μm
length of negative active material	z(2)	100 μm
length of separator	z(3)	50 μm
length of positive active material	z(4)	80 μm
length of positive current collector	z(5)	10 μm
discretization number in z-direction for separator	sep_nz	3
discretization number in z-direction for positive active material	ne_am_nz	3
discretization number in z-direction for negative active material	pe_am_nz	3
discretization number in z-direction for negative current collector	ne_cc_nz	2
discretization number in z-direction for positive current collector	pe_cc_nz	2
discretization number in x-direction interior region	int_elyte_nx	3
discretization number in x-direction negative tab region	ne_cc_nx	3
discretization number in x-direction positive tab region	pe_cc_nx	3
discretization number in y-direction interior region	elyte_ny	4
discretization number in y-direction negative tab region	ne_cc_ny	2
discretization number in y-direction positive tab region	pe_cc_ny	2

SpiralBatteryGenerator

A geometry model for jelly rolls. Here, we have used parameters corresponding to th 4680 model.

Thickness and discretization number (N) are passed through the dictionaries widthDict and nrDict, with values used in plot above.

Component	Key name	Length	N
Separator	Separator	50 μm	3
Negative Electrode Coating	NegativeCoating	94 μm	3
Negative Electrode Current Collector	NegativeCurrentCollector	25 μm	3
Positive Electrode Coating	PositiveCoating	84 μm	3
Positive Electrode Current Collector	PositiveCurrentCollector	10 μm	3

Other parameters, with values used in plot above.

Parameter	Name	Value
number of windings in the spiral	nwindings	52
Inner Radius correspoding to the empty space in the middle	rInner	2 mm
Height of the battery	L	70 mm
number of cells in the angular direction	nas	20
number of discretization cells in the longitudonal	nL	10

There are parameters for the tabs that we do not detail here, see json schema. The json source is available here.

CoinCellBatteryGenerator

A geometrical model for a coin cell.

Parameters for each component : thickness, diameter, number of cell layers (Nl), with the values used in the plot above (a CR 2016 coin cell)

Component	Key name	Thickness	Diameter	Nl
Negative electrode current collector	NegativeCurrentCollector	0.73 mm	20 mm	9
Negative electrode coating	NegativeCoating	50 μm	16 mm	3
Separator	Separator	20 μm	18 mm	2
Positive electrode coating	PositiveCoating	67 μm	16 mm	3
Positive electrode current collector	PositiveCurrentCollector	0.73 mm	20 mm	9

Other parameters, with values used in plot above

Parameter	Name	Value
Discretization number in radial direction	numRadial	7
Discretization number in angular direction	numAngular	30

BatteryGeneratorMultilayerPouch

A geometrical model for a multi-layer pouch cell.

Parameters for each component : thickness and number of cell (Nl) for a layer, with the values used in the plot above

Component	Name	Thickness	Nl
Negative electrode current collector	NegativeCurrentCollector	10 µm	2
Negative electrode coating	NegativeCoating	100 µm	3
Separator	Separator	50 μm	3
Positive electrode coating	PositiveCoating	80 μm	3
Positive electrode current collector	PositiveCurrentCollector	10 µm	2

Other parameters, with values used in plot above

Parameter	Name	Value
Number of Layers	nLayers	5
Width of the cell	width	10 cm
Length of the cell	length	10 cm
Discretization number for width	Electrolyte.Nx	2
Discretization number for length outside the tab	Electrolyte.Ny	2
Tabs width (same for negative and positive)	tab.width	5 cm
Tabs discretization number	tab.Nx	3
Tab lenght of negative electrode	tab.NegativeElectrode.length	4 cm
Tab length of positive electrode	tab.PositiveElectrode.length	2 cm

See json source file for this example.