Weijiang Power manufactures custom cylindrical lithium-ion battery packs built from 18650 and 21700 cells for power tools, e-bikes and scooters, portable electronics, lighting, medical and industrial devices. We supply assembled, BMS-protected and certified packs — with the cell configuration, capacity, housing and connector engineered to your device — rather than bare, unprotected cells. This page also explains the standard 18650 cylindrical cell that many of these packs are built from.
The 18650 is a widely used rechargeable lithium-ion cylindrical cell. Its name describes its dimensions: the first two digits give the 18 mm diameter, the next two the 65 mm length, and the final digit indicates a cylindrical form factor. A standard cell measures about 18 mm × 65 mm. Cells may be supplied with a button top or an integrated protection circuit, which can increase the length from about 65 mm to 70 mm or more, so the exact specification should always be confirmed against the device or pack design.
| Parameter | Custom Options |
|---|---|
| Cells | 18650 / 21700 cylindrical cells in series × parallel configurations |
| Voltage & capacity | Configured to the required voltage and runtime |
| Protection | PCM/BMS with over-charge, over-discharge, over-current and short-circuit protection; NTC thermistor on request |
| Mechanical | Welded nickel tabs, lead wires, connectors, shrink-wrap or custom housing |
| Certification | UN38.3, IEC 62133, CE, RoHS, REACH and MSDS documentation for shipping |
For applications that favour intrinsic safety, wide temperature tolerance and lower cost, compare our NiMH cells and packs; for finished pack solutions see lithium battery packs.
