Precision Manufacturing
From Cell to Pack
Umax operates 6 production lines -- 2 automated and 4 manual -- delivering consistent quality across prototypes, small-batch trials, and large-scale OEM production. Every pack passes our 11-step quality control process before shipment.
Lines
Steps
Projects
Not Just Assembly --
A Complete Battery Engineering Factory
Located in Shenzhen, China, Umax is a dedicated 18650 and 21700 cylindrical lithium battery pack manufacturer. We are not a trading company -- we own our production lines, control our quality process, and engineer each pack from cell selection through final delivery.
Our factory is positioned to serve B2B customers who require technical support, custom specifications, and reliable long-term supply. We work directly with drone manufacturers, robotics companies, industrial equipment OEMs, energy storage integrators, and branded product clients worldwide.
We own and operate all 6 production lines, ensuring direct quality oversight and faster response to customer requirements.
Our primary market is international B2B -- OEMs, brand owners, system integrators, and project-based clients who need reliable, technically supported battery supply.
We evaluate your application requirements -- voltage, current, size, weight, environment -- and engineer the right battery solution, not just the cheapest one.
2 Automated Production Lines
Designed for high-volume, high-consistency standard battery pack production. Our automated lines reduce human error, improve output speed, and ensure uniform quality across every batch.
High-Volume Standard Packs
Optimized for 18650 and 21700 standard cylindrical pack configurations. Handles cell sorting, spot welding, BMS connection, and aging test in a continuous automated workflow. Ideal for repeat orders with stable specifications.
Precision BMS Integration
Dedicated to automated BMS assembly, sampling wire connection, NTC temperature sensor integration, and final electrical testing. Supports intelligent BMS with SMBus, CAN, and UART communication for smart battery applications.
4 Manual Production Lines
Built for Complexity
Our 4 manual production lines are staffed by experienced technicians and are specifically designed for orders that require human judgment, fine craftsmanship, and flexible assembly -- things automated lines cannot handle alone.
From complex multi-cell structures and irregular housings to prototype development and special connector wiring, our manual lines give us the flexibility to build virtually any custom battery configuration our customers need.
Complex Structure Packs
Irregular shapes, multi-layer configurations, custom housing, and non-standard cell arrangements that require skilled manual assembly.
Prototype & Sample Development
First-article samples, engineering prototypes, and pre-production validation builds with fast turnaround and engineer support.
Special Wiring & Connectors
Custom wire harnesses, specific AWG gauges, XT60/XT90/EC5/Anderson/JST/Molex connectors, and multi-port configurations.
Low MOQ & Multi-SKU Orders
Flexible scheduling for small-batch orders, mixed-spec production runs, and customers requiring multiple configurations in one order.
From Idea to First Sample
in 7-14 Days
Our sample development process is fast, collaborative, and engineer-driven. We work directly with your technical team to confirm specifications, build the sample, test it, and refine it before mass production.
Step 1: Requirement Review
Share your device specs -- voltage, current, size, weight, connector, BMS requirements, and application. Our engineers review and propose the optimal cell and configuration.
Step 2: Sample Build
Our manual line team builds the first sample with confirmed cells, BMS, wiring, and housing. Each sample is assembled by experienced technicians and inspected before delivery.
Step 3: Test & Refine
Samples are tested for capacity, protection functions, voltage consistency, and temperature. Feedback from your team is incorporated into revised samples or directly into the production BOM.
What We Need From You
To start a sample, just share your basic requirements. No formal engineering drawings required for initial consultation.
Small Batch Trial Production
Before You Commit
After sample approval, we recommend a small trial production run -- typically 50 to 500 units -- to validate the production process, confirm quality consistency, and identify any issues before full-scale manufacturing begins.
Scalable Mass Production
With Consistent Quality
Once your design is validated, our automated lines take over. We scale efficiently from hundreds to tens of thousands of units per month while maintaining the same quality standards established during sample and trial stages.
Mass Production Strengths
Supported Production Scales
Built for the Projects
Others Won't Take
Our manual production lines and engineering team are specifically equipped to handle the most demanding custom battery projects. Unusual geometries, extreme current requirements, smart BMS communication, waterproof structures -- we've done it all.
Our Production Process
Every battery pack follows the same rigorous 11-step manufacturing and quality control process -- from incoming cell inspection to final shipment clearance.
Incoming Cell Inspection
Visual check, voltage, internal resistance, capacity, and batch verification of all incoming cells before production begins.
Cell Sorting & Matching
Cells sorted by capacity, internal resistance, and voltage to ensure tight consistency within each battery group.
Cell Array Design
Optimal cell arrangement planned based on pack dimensions, thermal management, structural load, and installation requirements.
Spot Welding
Nickel strips or composite nickel bands welded using precision spot welding equipment. Weld quality checked for conductivity and pull strength.
BMS Installation
BMS matched to pack voltage, capacity, and current. Sampling wires, main leads, NTC sensors, and communication lines connected and verified.
Insulation & Safety
Kraft paper, insulation sheets, epoxy board, PVC, EVA foam, and insulation tape applied at critical points to prevent shorts and structural movement.
Housing & Enclosure
PVC heat shrink, ABS/PC plastic shell, aluminum enclosure, or waterproof housing assembled per customer specification.
Charge & Discharge Test
Full charge/discharge cycle performed. Capacity, voltage consistency, protection trigger points, and recovery behavior verified.
Aging Test
Packs held at rest for 24+ hours. Voltage drift monitored to identify any latent cell or connection issues before shipment.
Final Inspection
Appearance, dimensions, labels, connectors, polarity, output voltage, protection functions, and packaging state all verified against order spec.
Export Packaging & Documentation
Packed per lithium battery transport regulations. MSDS, UN38.3, test reports, and OEM documentation prepared per customer requirement.
Purpose-Built Equipment
for Battery Pack Manufacturing
Every piece of equipment in our factory is selected and calibrated specifically for cylindrical lithium battery pack production -- from cell testing to final aging.
Cell Testing Equipment
Incoming QCAutomated cell sorters measure open-circuit voltage, internal resistance, and capacity for every incoming cell. Cells outside tolerance are rejected before production.
Precision Spot Welders
AssemblyPulse spot welding machines with adjustable energy settings ensure consistent, low-resistance nickel strip connections across all cell configurations and current requirements.
BMS Test Stations
VerificationDedicated BMS test stations verify all protection functions -- overcharge, over-discharge, overcurrent, short circuit, and temperature -- before packs proceed to aging.
Charge/Discharge Testers
Capacity QCMulti-channel charge/discharge testers measure actual pack capacity, voltage consistency across cells, and charge acceptance. Results logged per batch for traceability.
Aging Test Cabinets
Final QCFinished packs rest in aging cabinets for 24+ hours. Voltage drift is monitored continuously. Any pack showing abnormal self-discharge is quarantined and investigated.
Heat Shrink & Sealing Equipment
PackagingPVC heat shrink tunnels, ultrasonic welding, and adhesive sealing equipment for consistent, professional pack finishing and waterproof housing assembly.
Factory Advantages That
Make a Real Difference
Our production capabilities are built around one goal: delivering battery packs that perform reliably in your application, at the quality your customers expect, with the supply consistency your business needs.
Own Factory, No Middlemen
Direct factory control means faster communication, more accurate specifications, and no markup from intermediaries.
Expert Cell Selection
We evaluate your actual application requirements and match the right cell -- not just the most popular one.
Multi-Layer Safety Design
BMS protection, cell-level safeguards, structural insulation, and aging screening combine to deliver safe, stable packs.
11-Step QC Process
Every pack passes the same rigorous quality process -- incoming inspection, production checks, and final aging -- regardless of order size.
Flexible Production Scale
From 50-piece prototypes to 10,000+ monthly production -- our 6 lines adapt to your volume without compromising quality.
Full OEM / ODM Support
Custom branding, labels, packaging, documentation, and export compliance -- one factory handles everything.
Export-Ready Documentation
UN38.3, MSDS, test reports, and OEM documentation prepared for international shipments to 40+ countries.
Dedicated Engineer Per Project
Each project is assigned a dedicated engineer who understands your application and ensures the battery is designed right.
Smart BMS Capability
From basic protection to full SMBus/CAN/UART intelligent battery management -- we match BMS to your system requirements.
See Our Production
Capabilities Firsthand.
Let's Build Together.
We welcome factory visits from serious B2B customers and OEM partners. Or simply send us your battery requirements -- our engineers will respond with a tailored solution within 24 hours.