Flexible Copper Busbar Manufacturer | Multilayer & Flat Copper Flex Bars
Carsai manufactures custom flexible copper busbar products for battery systems, transformers, switchgear, busducts, power electronics and industrial electrical equipment.
A flexible copper conductor can carry high current while accommodating vibration, thermal expansion, terminal movement and installation misalignment. Compared with a rigid copper bar, it transfers less mechanical stress to the connected components.
Our custom products include:
- Multilayer copper foil busbars
- Flat flexible copper busbars
- Braided copper busbars
- Stranded copper flexible links
- Insulated flexible copper bars
- Tinned copper flex bars
- Battery and transformer connectors
- Flexible busbar jumpers and joints
- Custom terminals, holes and bends
Products are manufactured according to customer drawings, samples and electrical requirements.
For an overview of all available structures, visit our Flexible Busbar Manufacturer page.
What Is a Flexible Copper Busbar?
A flexible copper busbar is a flat or formed conductor designed to carry current while allowing controlled movement.
Common constructions include:
- Multiple thin copper foils stacked together
- Fine copper wires woven into a braid
- Several stranded copper ropes arranged in parallel
- Thin copper strips enclosed in insulation
Search terms such as flexible copper bus bar, flexible bus bar copper, copper flexible busbar and copper busbar flexible generally refer to the same product family.
Flexible copper busbars are commonly used when rigid conductors cannot safely absorb:
- Vibration
- Thermal expansion
- Terminal movement
- Assembly tolerance
- Equipment displacement
- Repeated mechanical stress
A typical product has a flexible central section and solid terminal areas at both ends.
Multilayer Copper Flex Bars
A multilayer flexible copper busbar is manufactured from several thin copper sheets or foils stacked together.
The layers can move slightly relative to one another, allowing the conductor to bend more easily than one solid copper bar of the same total cross-sectional area.
A multilayer copper flex bar may include:
- Two or more copper layers
- Press-welded terminal zones
- Drilled mounting holes
- Tin-plated surfaces
- Heat-shrink or PVC insulation
- Preformed bends or offsets
- Different terminal widths at each end
The total nominal copper cross-section is calculated from:
Number of layers × layer width × layer thickness
For example, ten copper layers measuring 30 mm wide and 0.3 mm thick provide a nominal copper section of 90 mm².
The actual current rating must still consider length, cooling, terminal resistance, enclosure temperature and insulation.
Flat Flexible Busbars
A flat flexible busbar provides a low-profile current path between electrical components.
It may use:
- Laminated copper foils
- Flat copper braid
- Multiple thin copper strips
- A flexible conductor enclosed in insulation
Flat conductors are especially useful where round cables and cable lugs require too much installation space.
Advantages may include:
- Compact routing
- Broad terminal contact areas
- Reduced connector height
- Fewer separate lugs
- Controlled hole positioning
- Easier integration with rigid busbars
- Custom bends and terminal shapes
The phrase copper flexible bar or flexible copper bar may describe either a multilayer flexible conductor or a relatively thin formed copper strip. The internal structure should therefore be confirmed before quotation.
Flexible Busbar Thickness
The keyword flexible busbar 3mm can refer to different constructions.
It may describe:
- A complete busbar approximately 3 mm thick
- Several copper layers with a total thickness of 3 mm
- One 3 mm copper strip with limited flexibility
- A flexible conductor plus an insulation layer
A solid 3 mm copper bar is not automatically a highly flexible busbar. Flexibility also depends on:
- Copper width
- Individual layer thickness
- Number of layers
- Flexible-section length
- Material condition
- Bend direction
- Insulation
- Terminal construction
For good multilayer flexibility, several thin copper layers are usually more suitable than one solid strip with the same total thickness.
The drawing should clearly state whether the 3 mm dimension refers to copper thickness or total finished thickness.
Flexible Copper Busbar Constructions
Laminated copper foil
Multiple thin copper foils are stacked and joined at the ends.
This structure provides:
- High current capability
- Broad, flat terminals
- Controlled bending direction
- Compact dimensions
- Easy integration with insulation
Braided copper
Fine copper wires are woven into a flexible flat or round conductor.
This structure offers:
- High multidirectional flexibility
- Good vibration absorption
- Grounding and bonding capability
- Long movement allowance
Stranded copper
Several round copper ropes or stranded conductors are arranged in parallel and connected to terminal plates.
This construction is suitable for:
- Large movement
- Long flexible sections
- Heavy-duty terminal plates
- Transformer and industrial applications
The correct construction depends on the required current, movement and available space.
Copper Materials and Surface Finishes
Bare copper
Bare electrical copper provides high conductivity and is suitable for many protected indoor applications.
Common grades may include:
- C11000
- Cu-ETP
- T2 copper
- Oxygen-free copper when specified
Tinned copper
Tin plating can help protect copper surfaces from oxidation and provide a consistent bolted-contact finish.
A tinned copper flex bar may be:
- Fully tin plated
- Selectively plated at the terminals
- Manufactured from pre-tinned copper braid
- Plated before insulation is applied
Nickel or silver plating
Nickel or silver may be used for specialized temperature, corrosion or contact requirements.
The required plating type, thickness and coverage should be shown on the drawing.
Insulated Flexible Copper Bars
An insulated flexible copper bar can be supplied with exposed terminal areas and a protected central conductor.
Available insulation options include:
- Heat-shrink tubing
- PVC sleeve
- Epoxy coating
- Powder coating
- Custom molded or plastic protection
Insulation may be required where the busbar passes close to:
- Opposite-polarity conductors
- Other phases
- Battery cells
- Grounded enclosures
- Equipment frames
- Other energized components
Insulation can reduce heat dissipation, so the operating temperature should be reviewed under actual installation conditions.
Terminal and Hole Options
Flexible copper busbars can be manufactured with:
- Single-hole terminals
- Two-hole terminals
- Multi-hole terminal plates
- Round holes
- Slotted holes
- Fork-shaped ends
- Different terminal widths
- Offset terminal planes
- Preformed bends
- Custom mounting palms
Important terminal specifications include:
- Hole diameter
- Hole spacing
- Edge distance
- Terminal thickness
- Contact area
- Terminal flatness
- Plating coverage
- Required fastening method
A properly sized flexible conductor can still overheat if the contact area is too small or the terminal joint is not assembled correctly.
Flexible Copper Busbar Applications
Battery systems
Flexible copper busbars can connect:
- Battery cells
- Battery modules
- BMS components
- Contactors
- Fuses
- Main positive and negative terminals
They can help reduce stress caused by cell movement, vibration and assembly tolerance.
Transformers
Transformer flexible links connect winding terminals to rigid busbars, switchgear or busduct systems.
They accommodate vibration, thermal expansion and slight misalignment.
Switchgear
Flexible conductors may connect:
- Circuit breakers
- Disconnect switches
- Contactors
- Main busbars
- Distribution conductors
- Power modules
Power electronics
Applications include:
- Inverters
- Rectifiers
- UPS systems
- EV chargers
- Industrial drives
- Energy storage systems
- Renewable-energy equipment
Current Capacity
There is no universal current rating based only on the visible width or thickness of a flexible busbar.
Current capacity depends on:
- Total copper cross-section
- Conductor construction
- Overall length
- Flexible-section length
- Continuous and peak current
- Ambient temperature
- Enclosure conditions
- Airflow
- Terminal resistance
- Insulation coverage
- Allowable temperature rise
A short, bare flexible busbar in open air may operate differently from a long insulated conductor inside a closed cabinet.
For high-current projects, provide both continuous and peak current requirements.
Manufacturing Process
A typical custom project includes:
- Reviewing the drawing and application
- Confirming copper grade and conductor structure
- Cutting copper foil, strip, braid or rope
- Stacking or assembling the flexible section
- Press welding or attaching terminal plates
- Punching or machining mounting holes
- Producing bends and offsets
- Deburring the edges
- Applying plating
- Adding insulation
- Inspecting dimensions and surfaces
- Packing the finished products
Prototype samples can be produced before repeat production when required.
Quality Inspection
Inspection may include:
- Copper material
- Overall length
- Flexible-section length
- Width and total thickness
- Individual layer thickness
- Hole diameter and spacing
- Bend position and angle
- Terminal flatness
- Plating coverage
- Insulation boundaries
- Surface condition
- Part identification
Approved drawings and reference samples help maintain consistency between batches.
Information Needed for a Quotation
Please provide:
- 2D or 3D drawing
- Copper grade
- Flexible conductor structure
- Width and thickness
- Number of layers
- Overall length
- Flexible-section length
- Hole quantity and spacing
- Terminal dimensions
- Continuous and peak current
- Bare or plated finish
- Insulation requirement
- Prototype quantity
- Production quantity
If a formal drawing is not available, a sample or dimensioned sketch can support the initial review.
Frequently Asked Questions
Is a flexible copper busbar the same as a flexible cable?
No. A flexible busbar normally has flat terminal areas and a low-profile conductor structure. A cable usually uses a round insulated conductor with crimped cable lugs.
Can a flexible busbar be 3 mm thick?
Yes, but the drawing should clarify whether 3 mm refers to the copper thickness or the complete insulated product thickness.
What is the difference between a multilayer and braided busbar?
A multilayer busbar uses stacked copper foils and bends mainly in a controlled direction. A braided busbar uses woven copper wires and offers greater multidirectional flexibility.
Can you make custom holes and bends?
Yes. Hole size, spacing, terminal shape, bend location and offset dimensions can be customized.
Can flexible copper busbars be tin plated and insulated?
Yes. The conductor can be tin plated and then partially insulated while leaving the terminal contact areas exposed.
Can you manufacture from a sample?
Yes. A sample can support product review, although a dimensioned drawing is recommended for repeat production.
Request a Flexible Copper Busbar Quotation
Carsai manufactures custom multilayer, flat, braided and insulated flexible copper busbars for batteries, transformers, switchgear and industrial power systems.
Send your drawing, copper dimensions, current, terminal design, surface finish, insulation and required quantity.
Request a custom flexible copper busbar quotation based on your drawing or sample.
