The wire is the "blood vessel" for energy transmission in lithium batteries. It should be selected based on the current size, voltage level and environmental conditions to avoid fire or performance degradation caused by wire overload.
1. Core parameters: Wire diameter (cross-sectional area) matches the current
The wire is the "blood vessel" for energy transmission in lithium batteries. It should be selected based on the current size, voltage level and environmental conditions to avoid fire or performance degradation caused by wire overload.
The relationship between current and wire diameter:
Wire diameter (AWG) cross-sectional area (mm ²) continuous current (A) applicable scenarios
22AWG 0.34 3-5A small current equipment (such as remote controls)
18AWG 0.82 8-12A power bank, small fan
14AWG 2.08 15-25A electric vehicle controller connection
10AWG 5.26 30-50A electric vehicle battery main circuit
8AWG 10.37 50-80A energy storage system for high current scenarios
Note: In high-current scenarios (such as the connection of electric vehicle motors), silicone wires (heat-resistant and flexible) or multi-strand twisted wires (to reduce skin effect) should be used, and single-strand hard wires should be avoided.
2. Material and insulation layer
Conductor material
Pure copper wire: It has the best electrical conductivity (low resistivity). Oxygen-free copper (purity ≥99.97%) is preferred, and copper-plated aluminum wire (prone to oxidation and high resistance) should be avoided. Nickel-plated wire: It is used for internal connection of lithium battery packs (nickel strip spot welding is convenient), with a thickness of ≥0.15mm and a width adjusted according to the current (for example, a 10mm wide nickel strip is required for a 10A current).
Insulating layer material
PVC: Low cost, but poor heat resistance (usually ≤70℃), suitable for indoor low-power scenarios.
Silicone rubber (silica gel) : Heat-resistant (-60℃ to 200℃), soft and flexible, suitable for outdoor, high-temperature or frequently moving scenarios (such as electric vehicles, drones).
Teflon (PTFE) : Heat-resistant (≤260℃), corrosion-resistant, used in extreme environments (such as industrial equipment, aerospace), but relatively expensive.
3. Interfaces and connection methods
Terminal/plug
For low current scenarios: Micro plugs such as JST and PH2.0 can be selected, and they need to be matched with protection board interfaces.
High current scenarios: Use Anderson plugs (such as SB50, SB120), XT90 plugs, or directly solder (make sure the solder joints are firm to avoid false connections and overheating).
Connection process
The internal nickel strip connection of the lithium battery pack should be made by ultrasonic welding or spot welding with a spot welder to avoid manual soldering (high temperature may damage the battery cells).
When connecting the external wires to the protective board, the solder joints need to be insulated (such as wrapped with heat shrink tubing) to prevent short circuits.
