Current Collectors¶
Current collectors are the metal foils onto which electrode coatings are applied. Four geometries are available:
| Type | Use Case |
|---|---|
| Notched | Tabless wound cells — notched foil edge for current collection |
| Tab-Welded | Wound cells with welded tab strips at specified positions |
| Punched | Stacked cells — punched foil with integral tabs |
| Tabless | Continuous foil with edge-based connections |
Notched¶
Notched current collector for tabless wound cells.
Classes¶
NotchedCurrentCollector(material: CurrentCollectorMaterial, length: float, width: float, thickness: float, tab_width: float, tab_spacing: float, tab_height: float, coated_tab_height: float = 0, bare_lengths_a_side: Tuple[float, float] = (0, 0), bare_lengths_b_side: Tuple[float, float] = (0, 0), insulation_width: Optional[float] = 0, name: Optional[str] = 'Notched Current Collector', datum: Optional[Tuple[float, float, float]] = (0, 0, 0), tab_center_positions: Optional[Iterable[float]] = None)
Bases: _TabbedCurrentCollector, _TapeCurrentCollector
The notched current collector combines features from both tabbed and tape connection methods. It features multiple tabs along its length for improved current distribution and configurable bare regions for tape-style connections, offering excellent flexibility for various cell architectures and connection strategies.
Parameters¶
material : CurrentCollectorMaterial Material composition defining electrical, thermal, and mechanical properties Selection impacts resistance, cost, and compatibility with active materials length : float Total length of the collector in the primary direction (mm) Determines the number of tabs that can be accommodated width : float Width of the collector perpendicular to the length (mm) Affects current path lengths and collector resistance thickness : float Material thickness in micrometers (μm) Impacts electrical resistance and mechanical stiffness tab_width : float Width of each individual tab (mm) Should be optimized for current density and manufacturing constraints tab_spacing : float Center-to-center distance between adjacent tabs (mm) Determines current distribution uniformity tab_height : float Extension height of tabs beyond the foil (mm) Must provide adequate access for welding and connections coated_tab_height : float, optional Height of active material coating on each tab (mm, default: 0) Allows for energy density optimization while maintaining connections bare_lengths_a_side : tuple of float, optional (start, end) uncoated lengths on a-side for tape connections (mm) Enables hybrid connection strategies bare_lengths_b_side : tuple of float, optional (start, end) uncoated lengths on b-side for tape connections (mm) Provides flexibility for asymmetric designs insulation_width : float, optional Width of insulation strip around perimeter (mm, default: 0) name : str, optional Descriptive identifier for the collector datum : tuple of float, optional Reference coordinate system origin (x, y, z) in mm
Examples¶
Create a high-performance notched collector for an EV battery:
from steer_materials import copper_foil_12um collector = NotchedCurrentCollector( ... material=copper_foil_12um, ... length=2500.0, # mm - large format cell ... width=180.0, # mm ... thickness=12.0, # μm ... tab_width=30.0, # mm - wide tabs for high current ... tab_spacing=50.0, # mm - 5 tabs total ... tab_height=15.0, # mm ... coated_tab_height=10.0, # Partially coated tabs ... bare_lengths_a_side=(15.0, 15.0), # Tape connection option ... bare_lengths_b_side=(10.0, 10.0) ... ) print(f"Number of tabs: {collector.n_tabs}") print(f"Total tab area: {collector.total_tab_area:.1f} mm²") print(f"Effective resistance: {collector.effective_resistance:.6f} Ω")
thermal_fig = collector.get_thermal_map() thermal_fig.show()
Compare connection strategies:
print("Available connections:", collector.connection_flexibility.keys())
Output: ['tab_welding', 'tape_welding_a', 'tape_welding_b', 'hybrid']¶
See Also¶
PunchedCurrentCollector : Simple single-tab design TablessCurrentCollector : Tape-only connection without tabs TabWeldedCurrentCollector : Separate welded tab approach _TabbedCurrentCollector : Base class for tab functionality _TapeCurrentCollector : Base class for tape functionality
Initialize an object that represents a notched current collector.
Parameters¶
material : CurrentCollectorMaterial
Material of the current collector.
length : float
Length of the current collector in mm.
width : float
Width of the current collector in mm.
thickness : float
Thickness of the current collector in µm.
tab_width : float
Width of the tabs in mm.
tab_spacing : float
Spacing between the tabs in mm.
tab_height : float
Height of the tabs in mm.
tab_center_positions : iterable of float, optional
Explicit tab center positions measured from the leading edge of the
foil in mm. When provided, these thickness-aware or otherwise
custom positions take precedence over tab_spacing.
coated_tab_height : float
Height of the coated tab on the top side in mm.
bare_lengths_a_side : Tuple[float, float]
Bare lengths on the A side in mm, as a tuple of two floats (left, right).
bare_lengths_b_side : Tuple[float, float]
Bare lengths on the B side in mm, as a tuple of two floats (left, right).
insulation_width : Optional[float], default=0
Width of the insulation strip in mm.
name : Optional[str], default='Notched Current Collector'
Name of the current collector.
datum : Optional[Tuple[float, float, float]], default=(0, 0, 0)
Datum of the current collector in mm.
Attributes¶
property
writable
¶
Return the active explicit centers from the foil leading edge in mm.
None means the uniform tab_spacing pattern is in use. As with
weld_tab_positions, this reports the centers actually in effect:
assembly-generated centers while notch alignment is active, otherwise
the requested centers that still fit the current geometry.
property
¶
Return the explicit centers as requested, in mm, including inactive ones.
property
¶
Get the tab spacing range in mm.
property
¶
Same as tab_width_range: the racetrack limit is not negotiable.
property
¶
Valid tab width in mm, capped by the racetrack when flat-wound.
A notch has to sit on a flat face of the wound profile, so it can never be wider than the pressed mandrel's straight section. Outside a flat-wound roll -- standalone, or in a cylindrical one, which has no straight section -- the generic component limit applies.
Methods:¶
classmethod
¶
from_tabless(tabless) -> NotchedCurrentCollector
Create a NotchedCurrentCollector from a TablessCurrentCollector.
classmethod
¶
from_tab_welded(tab_welded) -> NotchedCurrentCollector
Create a NotchedCurrentCollector from a TabWeldedCurrentCollector.
Tab-Welded¶
Tab-welded current collector with discrete weld tabs.
Classes¶
WeldTab(material: CurrentCollectorMaterial, width: float, length: float, thickness: float, datum: Tuple[float, float] = (0, 0, 0))
Bases: PropagationMixin, ValidationMixin, CoordinateMixin, DatumMixin, DunderMixin, PlotterMixin, SerializerMixin
Specification and modeling class for separately manufactured welded tabs.
The WeldTab class represents individual tab components that are manufactured separately and subsequently welded to current collectors. This design approach enables independent optimization of tab materials, geometry, and properties while providing sophisticated control over electrical and mechanical performance characteristics.
Parameters¶
material : CurrentCollectorMaterial Material specification for the tab component Defines electrical, thermal, and mechanical properties Must be compatible with welding processes and base collector material width : float Tab width dimension in mm Affects current carrying capacity and mechanical strength Typical range: 10-100 mm depending on application requirements length : float Tab length dimension in mm Determines contact area and current distribution characteristics Typical range: 5-50 mm for most battery applications thickness : float Tab thickness in μm Critical for electrical resistance and mechanical robustness Typical range: 50-500 μm based on current requirements datum : tuple of float, optional Reference coordinate system origin (x, y, z) in mm Default: (0, 0, 0) - places tab at coordinate system origin
Examples¶
Create a high-performance copper tab for EV applications:
from steer_materials import CurrentCollectorMaterial
Design a robust tab for high current applications¶
heavy_duty_tab = WeldTab( ... material=CurrentCollectorMaterial.from_database('Copper'), ... width=50.0, # mm - wide for high current ... length=25.0, # mm - substantial contact area ... thickness=200.0, # μm - thick for low resistance ... datum=(0, 0, 0) # Centered reference ... )
print(f"Tab resistance: {heavy_duty_tab.electrical_resistance:.6f} Ω") print(f"Tab mass: {heavy_duty_tab.mass:.3f} g") print(f"Current capacity: {heavy_duty_tab.current_density_limit * heavy_duty_tab.foil_area/2:.1f} A")
Create a compact tab for space-constrained applications:
Design for minimal size while maintaining performance¶
compact_tab = WeldTab( ... material=CurrentCollectorMaterial.from_database('Copper'), ... width=20.0, # mm - compact width ... length=15.0, # mm - minimal length ... thickness=150.0, # μm - optimized thickness ... datum=(10, 5, 0) # Offset positioning ... )
Visualize tab geometry and validate design:
Generate visualization plots¶
top_view = heavy_duty_tab.plot_view( ... title="Heavy Duty Tab - Top View", ... paper_bgcolor='lightgray' ... ) side_view = heavy_duty_tab.plot_side_view( ... title="Heavy Duty Tab - Side View" ... )
Validate welding compatibility¶
from steer_materials import aluminum_1235_foil compatibility = heavy_duty_tab.validate_welding_compatibility( ... aluminum_1235_foil ... ) if not compatibility['suitable']: ... print("Warning: Material incompatibility detected")
See Also¶
TabWeldedCurrentCollector : Current collector using welded tabs CurrentCollectorMaterial : Material specification class PunchedCurrentCollector : Alternative integrated tab design NotchedCurrentCollector : Multiple integrated tab approach
Initialize an object that represents a weld tab used on current collectors
:param material: CurrentCollectorMaterial: material of the weld tab :param width: float: width of the weld tab in mm :param length: float: length of the weld tab in mm :param thickness: float: thickness of the weld tab in um
TabWeldedCurrentCollector(material: CurrentCollectorMaterial, length: float, width: float, thickness: float, weld_tab: WeldTab, weld_tab_positions: Iterable[float], skip_coat_width: float, tab_overhang: float, tab_weld_side: str = 'a', bare_lengths_a_side: Tuple[float, float] = (0, 0), bare_lengths_b_side: Tuple[float, float] = (0, 0), name: Optional[str] = 'Tab Welded Current Collector', datum: Optional[Tuple[float, float, float]] = (0, 0, 0))
Bases: _TapeCurrentCollector
Current collector with separately manufactured and welded tabs.
The tab-welded current collector represents a design approach where tabs are manufactured separately and then welded to the main collector foil.
Parameters¶
material : CurrentCollectorMaterial Base material for the current collector foil Can be optimized independently from tab material length : float Total length of the collector foil in mm Defines the available space for tab positioning width : float Width of the collector foil in mm Affects current distribution and tab placement options thickness : float Thickness of the base collector material in μm May differ from tab thickness for optimized performance weld_tab : WeldTab Specification object defining tab geometry, material, and properties Encapsulates all tab-specific design parameters weld_tab_positions : Iterable[float] Array of tab center positions along the length in mm Enables precise, flexible tab placement for optimal current distribution skip_coat_width : float Width of uncoated area around each tab in mm Prevents coating interference with welding and ensures reliable connections tab_overhang : float Distance tabs extend beyond the collector foil edge in mm Provides access for external connections and welding operations tab_weld_side : str, optional Side of collector for tab welding ('a' or 'b', default: 'a') Determines which surface receives the welded tabs bare_lengths_a_side : tuple of float, optional (start, end) uncoated regions on a-side in mm Enables hybrid connection strategies combining tabs and tape methods bare_lengths_b_side : tuple of float, optional (start, end) uncoated regions on b-side in mm Provides additional connection flexibility name : str, optional Descriptive identifier for the collector assembly datum : tuple of float, optional Reference coordinate system origin (x, y, z) in mm
Examples¶
Create a high-performance tab-welded collector for an EV application:
from steer_materials import CurrentCollectorMaterial
Define the weld tab specification¶
weld_tab = WeldTab( ... material=CurrentCollectorMaterial.from_database('Copper'), ... width=40.0, # mm - wide for high current ... height=20.0, # mm ... thickness=100.0 # μm - thick for low resistance ... )
Create collector with optimally positioned tabs¶
collector = TabWeldedCurrentCollector( ... material=CurrentCollectorMaterial.from_database('Copper'), ... length=300.0, # mm ... width=200.0, # mm ... thickness=15.0, # μm ... weld_tab=weld_tab, ... weld_tab_positions=[75.0, 150.0, 225.0], # 3 evenly spaced tabs ... skip_coat_width=45.0, # mm - larger than tab width ... tab_overhang=18.0, # mm - accessible for connections ... tab_weld_side='a', ... bare_lengths_a_side=(20.0, 20.0) # Additional tape connection option ... )
See Also¶
PunchedCurrentCollector : Simpler integrated tab design NotchedCurrentCollector : Multiple integrated tabs TablessCurrentCollector : No-tab edge connection design WeldTab : Specification class for welded tab components
Initialize an object that represents a current collector with tabs welded on it.
Parameters¶
material: CurrentCollectorMaterial: Material of the current collector. length: float: Length of the current collector in mm. width: float: Width of the current collector in mm. thickness: float: Thickness of the current collector in um. weld_tab: WeldTab: Weld tab to be used on the current collector. weld_tab_positions: Iterable[float]: Positions of the weld tabs along the length of the current collector in mm. skip_coat_width: float: Width of the skip coat area in mm. tab_overhang: float: Overhang of the weld tab in mm. tab_weld_side: str: Side of the current collector where the weld tabs are welded ('a' or 'b'). bare_lengths_a_side: Tuple[float, float]: Bare lengths on the A side in mm, as a tuple of two floats (left, right). bare_lengths_b_side: Tuple[float, float]: Bare lengths on the B side in mm, as a tuple of two floats (left, right). name: Optional[str]: Name of the current collector, default is 'Tab Welded Current Collector'. datum: Optional[Tuple[float, float, float]]: Datum of the current collector in mm, default is (0, 0, 0).
Attributes¶
property
writable
¶
Returns the positions of the weld tabs along the length of the current collector in mm.
property
writable
¶
Returns the width of the skip coat area in mm.
property
¶
Get the skip coat width range in mm.
property
¶
Get the skip coat width range in mm.
property
writable
¶
Returns the side of the current collector where the weld tabs are located ('a' or 'b').
property
writable
¶
Returns the overhang of the weld tab on the current collector in mm.
property
¶
Returns the overhang range of the weld tab in mm.
property
writable
¶
weld_tab: WeldTab
Returns the WeldTab object representing the weld tab specification on the current collector.
property
¶
Returns a list of WeldTab objects representing the weld tabs on the current collector.
property
¶
Returns the width range of the weld tab in mm.
property
¶
Returns the length range of the weld tab in mm.
property
writable
¶
Returns the weld tab positions as a formatted string in mm.
Returns¶
str Comma-separated string of tab positions (e.g., "75.0, 150.0, 225.0")
Methods:¶
classmethod
¶
from_notched(notched) -> TabWeldedCurrentCollector
Create a TabWeldedCurrentCollector from a NotchedCurrentCollector.
classmethod
¶
from_tabless(tabless) -> TabWeldedCurrentCollector
Create a TabWeldedCurrentCollector from a TablessCurrentCollector.
Punched¶
Punched current collector with integral tabs for stacked cells.
Classes¶
PunchedCurrentCollector(material: CurrentCollectorMaterial, width: float, height: float, thickness: float, tab_width: float, tab_height: float, tab_position: float, coated_tab_height: float = 0, insulation_width: Optional[float] = 0, name: Optional[str] = 'Punched Current Collector', datum: Optional[Tuple[float, float, float]] = (0, 0, 0))
Bases: _TabbedCurrentCollector
Simple rectangular current collector with a single integrated tab.
The punched current collector is the most common and straightforward collector design, featuring a rectangular foil with a single tab extending from one edge. This design is widely used in prismatic and pouch cell formats due to its simplicity, manufacturing efficiency, and reliable electrical performance.
Key characteristics: - Simple rectangular geometry with minimal complexity - Single tab for electrical connection - Configurable tab position along the width - Suitable for high-volume manufacturing - Compatible with standard coating and assembly processes
This collector type is particularly well-suited for: - Z-fold electrode assemblies - Flat sheet cell constructions - Applications requiring simple, cost-effective designs - Automated manufacturing processes
Parameters¶
material : CurrentCollectorMaterial Material composition defining electrical and mechanical properties Common materials: aluminum foil (cathode), copper foil (anode) width : float Total width of the collector foil in mm Typical range: 50-300 mm depending on cell capacity height : float Total height of the collector foil in mm Typical range: 50-500 mm depending on cell format thickness : float Material thickness in micrometers (μm) Typical range: 6-20 μm (Al), 8-35 μm (Cu) tab_width : float Width of the protruding tab in mm Typical range: 10-50 mm based on current requirements Should be optimized for current density and welding requirements tab_height : float Extension height of the tab beyond the foil in mm Typical range: 5-25 mm for manufacturing and assembly accessibility tab_position : float Horizontal position of the tab center from the left edge in mm Range: tab_width/2 to (width - tab_width/2) Central positioning (width/2) provides optimal current distribution coated_tab_height : float, optional Height of active material coating on the tab in mm (default: 0) Must be less than tab_height to provide bare connection area Set to 0 for completely uncoated tabs insulation_width : float, optional Width of insulation strip around the perimeter in mm (default: 0) Helps prevent short circuits and improves safety name : str, optional Descriptive name for identification datum : tuple of float, optional Reference coordinate system origin (x, y, z) in mm
Attributes¶
foil_area : float Surface area of the rectangular foil excluding tab (mm²) tab_area : float Surface area of the tab extension (mm²) total_area : float Combined surface area of foil and tab (mm²) coated_area : float Area available for active material coating (mm²) current_density : float Current density through the tab connection (A/mm²) resistance : float Electrical resistance from foil center to tab (Ω)
Methods¶
get_footprint() Returns the 2D outline coordinates of the collector plot_a_side_view() Generates plotly figure of the collector from above get_properties() Returns dictionary of all geometric and electrical properties
Examples¶
Create a standard punched cathode current collector:
from steer_materials import aluminum_foil_12um collector = PunchedCurrentCollector( ... material=aluminum_foil_12um, ... width=150.0, # mm ... height=200.0, # mm ... thickness=12.0, # μm ... tab_width=25.0, # mm ... tab_height=10.0, # mm ... tab_position=75.0 # mm (centered) ... ) print(f"Coated area: {collector.coated_area:.1f} mm²") print(f"Tab current density at 10A: {10/collector.tab_area:.2f} A/mm²")
Create an anode collector with coated tab:
from steer_materials import CurrentCollectorMaterial anode_collector = PunchedCurrentCollector( ... material=CurrentCollectorMaterial.from_database('Aluminum'), ... width=152.0, # Slightly larger than cathode ... height=202.0, ... thickness=10.0, ... tab_width=20.0, ... tab_height=12.0, ... tab_position=74.0, ... coated_tab_height=8.0 # Partial coating on tab ... )
Visualize the collector geometry:
fig = collector.plot_a_side_view() fig.show() # Interactive plotly visualization
See Also¶
_TabbedCurrentCollector : Base class providing shared tab / foil / coating
parameters (material, thickness, insulation_width, name,
datum) that are inherited here.
NotchedCurrentCollector : Collector with cutout features for tape connections
TablessCurrentCollector : Collector without protruding tabs
TabWeldedCurrentCollector : Collector with separately welded tabs
Initialize an object that represents a punched current collector.
Parameters¶
material: CurrentCollectorMaterial Material of the current collector. width: float Width of the current collector in mm. height: float Height of the current collector in mm. tab_width: float Width of the tab in mm. tab_height: float Height of the tab in mm. tab_position: float Position of the tab in mm, relative to the left edge of the current collector. coated_tab_height: float Height of the coated tab on the top side in mm, default is 0. thickness: float Thickness of the current collector in um. insulation_width: Optional[float] Width of the insulation in mm, default is 0. name: Optional[str] Name of the current collector, default is 'Punched Current Collector'. datum: Optional[Tuple[float, float, float]] Datum of the current collector in mm, default is (0, 0, 0).
Tabless¶
Tabless current collector with edge-based connections.
Classes¶
TablessCurrentCollector(material: CurrentCollectorMaterial, length: float, width: float, coated_width: float, thickness: float, bare_lengths_a_side: Tuple[float, float] = (0, 0), bare_lengths_b_side: Tuple[float, float] = (0, 0), insulation_width: Optional[float] = 0, name: Optional[str] = 'Tabless Current Collector', datum: Optional[Tuple[float, float, float]] = (0, 0, 0))
Bases: NotchedCurrentCollector
Streamlined current collector without protruding tabs.
The tabless current collector represents the most space-efficient design,` eliminating protruding tabs entirely in favor of edge-based connections. This design is particularly advantageous for cylindrical cells, flatwound configurations, and applications where minimizing cell volume and complexity are paramount.
Key advantages of the tabless design: - Simplified manufacturing with fewer cutting/forming operations - Reduced risk of tab damage during handling and assembly - Better suitability for automated winding and stacking processes - Lower material waste during production - Enhanced mechanical robustness
This design is especially well-suited for: - Cylindrical cells (18650, 21700, 4680 formats) - Flatwound rectangular cells - High-volume consumer applications - Cells requiring consistent cylindrical geometry - Applications where tab damage is a reliability concern
Parameters¶
material : CurrentCollectorMaterial Material composition for electrical and mechanical properties Typically aluminum for cathodes, copper for anodes length : float Total length of the collector in the primary direction (mm) For cylindrical cells, this determines the winding length width : float Total width of the collector (mm) For cylindrical cells, this affects the electrode height coated_width : float Width of the region available for active material coating (mm) Must be less than total width to provide bare connection strips thickness : float Material thickness in micrometers (μm) Affects cell internal resistance and energy density bare_lengths_a_side : tuple of float, optional (start, end) uncoated lengths on a-side for connections (mm) Provides flexibility for different cell termination strategies bare_lengths_b_side : tuple of float, optional (start, end) uncoated lengths on b-side for connections (mm) Enables asymmetric designs for specific applications insulation_width : float, optional Width of insulation strip around edges (mm, default: 0) Critical for preventing short circuits in tabless designs name : str, optional Descriptive identifier for the collector datum : tuple of float, optional Reference coordinate system origin (x, y, z) in mm
Examples¶
Design a tabless collector for a 21700 cylindrical cell:
from steer_materials import CurrentCollectorMaterial collector = TablessCurrentCollector( ... material=CurrentCollectorMaterial.from_database('Aluminum'), ... length=650.0, # mm - enough for multiple winds ... width=65.0, # mm - fits 21700 height ... coated_width=60.0, # mm - 2.5mm bare strips on edges ... thickness=15.0, # μm ... bare_lengths_a_side=(10.0, 10.0), # mm ... bare_lengths_b_side=(10.0, 10.0), # mm ... insulation_width=0.5 # mm - prevent shorts ... ) print(f"Coated fraction: {collector.coated_fraction:.2%}") print(f"Connection strip width: {collector.connection_strip_width:.1f} mm")
See Also¶
NotchedCurrentCollector : Direct parent class providing tab + tape behaviour.
_TabbedCurrentCollector : Indirect base; documents shared tab / foil /
coating parameters (material, thickness, insulation_width,
name, datum).
_TapeCurrentCollector : Indirect base; documents bare_lengths_a_side
and bare_lengths_b_side semantics.
PunchedCurrentCollector : Simple tabbed alternative
TabWeldedCurrentCollector : Separate welded tab approach
Initialize an object that represents a tabless current collector.
Parameters¶
material: CurrentCollectorMaterial: Material of the current collector. length: float: Length of the current collector in mm. width: float: Width of the current collector in mm. coated_width: float: Width of the coated area in mm. thickness: float: Thickness of the current collector in um. bare_lengths_a_side: Tuple[float, float]: Bare lengths on the A side in mm, as a tuple of two floats (left, right). bare_lengths_b_side: Tuple[float, float]: Bare lengths on the B side in mm, as a tuple of two floats (left, right). insulation_width: Optional[float]: Width of the insulation strip in mm, default is 0. name: Optional[str]: Name of the current collector, default is 'Tabless Current Collector'.
Attributes¶
property
¶
Get the coated width range in mm.
property
¶
Get the coated width range in mm.
Methods:¶
classmethod
¶
from_notched(notched: NotchedCurrentCollector) -> TablessCurrentCollector
Create a TablessCurrentCollector from a NotchedCurrentCollector.
classmethod
¶
from_tab_welded(tab_welded: TabWeldedCurrentCollector) -> TablessCurrentCollector
Create a TablessCurrentCollector from a TabWeldedCurrentCollector.