21700 4P Adhesive Fish Paper Positive Terminal Insulators

Protect the positive terminal side of your 21700 battery modules with pre-cut adhesive fish paper insulators designed for straight 4P cell groups.

Each insulator covers one four-cell parallel group and includes four terminal openings that leave the intended positive contact areas accessible while adding an insulating layer around the surrounding cell tops.

These pre-cut pieces help simplify battery-pack assembly by eliminating the need to measure and hand-cut individual fish paper rings for every 4P module.

Key Features

• Designed for straight 21700 4P cell groups
• Covers four positive cell terminals with one connected piece
• Pre-cut terminal openings
• Adhesive backing helps hold the insulator in position
• Helps protect cell wrappers around the positive terminals
• Helps isolate nickel, copper, and other conductive materials from the cell shoulders
• Faster and more consistent than cutting individual terminal rings
• Available in 10-, 12-, and 24-piece packs

Pack Size Options

Each insulator covers one 21700 4P parallel group.

• 10-Pack: Covers up to ten 4P groups; suitable for a typical 10S4P pack
• 12-Pack: Covers up to twelve 4P groups; suitable for a typical 12S4P pack
• 24-Pack: Covers up to twenty-four 4P groups; useful for two 12S4P packs, multiple builds, repairs, or spare material

Always confirm the number and arrangement of parallel groups in your specific battery design before ordering.

Common Applications

These insulators are commonly used for:

• 10S4P electric skateboard batteries
• 12S4P electric skateboard batteries
• Modular 21700 battery packs
• Straight four-cell parallel modules
• DIY electric-vehicle batteries
• Repairing or replacing damaged terminal insulation
• Protecting positive cell ends before installing nickel or copper conductors

Why Positive Terminal Insulation Matters

The positive terminal area of a cylindrical lithium-ion cell sits close to the electrically negative outer cell can.

Damaged wrappers, misplaced conductors, sharp nickel edges, or conductive material bridging this area may create a short circuit.

A properly fitted fish paper insulator adds a protective barrier around the positive terminal and helps reduce the risk of conductive material contacting the cell shoulder or can.

These insulators are one component of a complete battery insulation system and should be used alongside intact cell wrappers, proper conductor placement, structural protection, and safe assembly practices.

Specifications

• Cell size: 21700
• Parallel-group format: Straight 4P
• Material: Electrical insulation fish paper
• Backing: Pressure-sensitive adhesive
• Application: Positive terminal insulation
• Terminal openings: Four per insulator
• Available quantities: 10, 12, or 24 pieces

Confirm the exact dimensions and hole spacing match your cell layout, holders, and conductor design before installation.

Installation

1. Confirm that all cell wrappers and positive-terminal rings are undamaged.
2. Clean the cell tops and remove dust, oil, loose debris, or conductive material.
3. Test-fit the insulator before removing the adhesive liner.
4. Align all four openings with the positive terminals.
5. Remove the backing and apply the insulator evenly.
6. Press the fish paper securely around each terminal area.
7. Confirm that no material overlaps the required electrical contact points.
8. Inspect the completed module before spot welding or installing conductors.

Do not force the insulator onto an incompatible cell arrangement or use it to conceal damaged cell wrappers.

What’s Included

Choose one:

• 10 adhesive fish paper positive-terminal insulators
• 12 adhesive fish paper positive-terminal insulators
• 24 adhesive fish paper positive-terminal insulators

Cells, nickel strip, copper, cell holders, wiring, and battery-building tools are not included.

Important Safety Information

Lithium-ion battery construction can cause fire, serious injury, or property damage if completed incorrectly.

Fish paper does not replace:

• Intact cell wrappers
• Individual positive-terminal protection where required
• Proper electrical spacing
• Correct conductor design
• Short-circuit protection
• Mechanical support
• Complete electrical testing

Battery packs should only be assembled or repaired by someone familiar with lithium-ion cell handling, polarity, spot welding, insulation, and short-circuit prevention.