Custom Battery Solutions & OEM Packs | COSOMIC

Q: What is the difference between 2000mAh, 2600mAh, 3000mAh, and 3500mAh 18650 cells?

The capacity directly determines runtime — a 3500mAh cell stores 75% more energy than a 2000mAh cell. Higher capacity cells typically use denser NMC cathode materials. For pack assembly, never mix different capacities in the same series string, as this causes imbalance and premature failure.

Q: Can I use these cells to build a custom battery pack?

Yes. Our 18650 cells are designed for spot-welding assembly into 2S–14S custom battery packs. We recommend using 0.15–0.2mm pure nickel strip and a battery management system (BMS) for any multi-cell pack. All cells within a pack must be from the same batch with matched capacity and internal resistance.

Q: Are these cells certified for international air freight?

Yes. Every batch carries UN38.3 test summary and MSDS documentation, meeting IATA and ICAO requirements for lithium-ion cell air transport. We provide compliant packaging with hazard labels and shipper declarations for all international orders.

Q: What is the minimum order quantity and lead time?

Sample MOQ is 100 pcs with a 3–5 day lead time from our Foshan factory. Mass production MOQ is 1,000 pcs with a 7–15 day lead time. For orders above 50,000 pcs, contact our sales team for dedicated production scheduling and volume pricing.

Q: Do you offer flat-top and button-top terminal options?

Yes. We supply both flat-top cells (for spot-welding pack assembly) and button-top cells (for spring-contact devices like flashlights). Please specify your terminal requirement when ordering. Button-top cells add approximately $0.02/pcs to the base price.

Q: What payment terms do you accept?

We accept T/T (Telegraphic Transfer / Wire Transfer) for all 18650 cell orders. Standard terms are 30% deposit before production and 70% balance before shipment. For established customers with order history, we offer net-30 terms upon credit approval.

One-stop China OEM & ODM manufacturer for custom lithium battery packs, cells & modules. Best price, CE, UN38.3, ISO 9001 certified. 200+ global clients, 50+ countries served since 2018. Request a quote: +86 158 8990 0503.

cosomicexpert of battery packs

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cosomicexpert of battery packs

Discuss Your Project

18650 Li-ion Cells

18650 Li-ion Cells
Direct from Factory

Grade-A cylindrical lithium-ion cells — 2000mAh to 3500mAh, 3.7V/4.2V, EXW $0.80–$2.20/pcs. Certified, consistent, and ready for battery pack assembly, power tools, flashlights, medical devices, and IoT applications.

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Application Overview

The Foundation of Modern Portable Power

The 18650 cylindrical lithium-ion cell is the most widely used rechargeable battery format in the world. From Tesla battery modules to laptop packs, power tools, flashlights, and medical devices — the 18650 format dominates because of its optimal balance between energy density, safety, manufacturing consistency, and cost. We supply Grade-A 18650 cells in capacities from 2000mAh to 3500mAh with tight internal resistance tolerance, consistent capacity grading, and full UN38.3 / MSDS certification for global shipping. Whether you are assembling custom battery packs, replacing existing cells, or building a new product line, our factory-direct pricing and fast sample turnaround give you a competitive edge.

Key Engineering Challenges

Ensuring consistent capacity and internal resistance across large batches for pack assembly

Meeting UN38.3 and IATA shipping requirements for international air freight of lithium cells

Preventing cell mixing (different ages, capacities, brands) that causes imbalance and early failure

Sourcing genuine Grade-A cells vs. recycled or B-grade cells that degrade rapidly

Managing thermal runaway risks during high-current series/parallel pack assembly

Engineering Requirements

What Every 18650 Li-ion Cells Battery Must Deliver

Grade-A Consistency

Capacity variance ≤2%, internal resistance matched within 5mΩ per batch — essential for safe pack assembly.

High-Drain Options

2000mAh cells optimized for 2C–3C discharge — ideal for power tools, flashlights, and high-drain devices.

UN38.3 Certified Shipping

Every batch carries UN38.3 test summary and MSDS for compliant international air and sea freight.

Pack-Assembly Ready

Flat-top and button-top options, pure nickel strip compatible, spot-weld friendly cell terminals.

Typical Specifications

Engineered to Your Exact Requirements

These are the typical parameter ranges for 18650 li-ion cells battery systems. Every project is custom-engineered to your specific application requirements.

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Cell Format18650 cylindrical (18.3mm × 65.0mm)

Nominal Voltage3.7V (Li-ion NMC)

Max Charge Voltage4.2V ± 0.05V

Capacity Options2000mAh / 2600mAh / 3000mAh / 3500mAh

Continuous Discharge1C–3C (2A–9A depending on model)

Cycle Life≥ 500 cycles @ 80% DoD

Internal Resistance≤ 60mΩ (new cell, 100% SOC)

Operating Temperature-20°C to +60°C (discharge); 0°C to +45°C (charge)

Storage Temperature-40°C to +70°C (40–60% SOC recommended)

Weight≈ 45–52g per cell

Terminal TypesFlat-top (welding) / Button-top (spring contact)

CertificationsCE, UN38.3, RoHS, MSDS

Regulatory Compliance

Certifications for 18650 Li-ion Cells

UN38.3

UN transport safety certification required for international air, sea, and road shipment of lithium-ion cells. Every batch is tested and documented.

CE Marking

European conformity marking confirming compliance with EU safety, health, and environmental protection standards for battery products.

RoHS

Restriction of Hazardous Substances directive ensuring cells are free from lead, mercury, cadmium, and other restricted materials.

MSDS

Material Safety Data Sheet providing detailed chemical composition, hazard classification, and safe handling instructions for logistics and customs.

ISO 9001

Quality management system certification covering incoming inspection, cell grading, batch testing, and traceability documentation.

Real Projects

18650 Li-ion Cells Case Studies

🇰🇪 KenyaEast African Smart Metering Utility

3.6V 19Ah Li-SOCl₂ Pack for 15,000-Node Off-Grid Smart Meter Network

15,000 nodes · zero replacements

Challenge

A Kenyan utility needed to deploy 15,000 smart meters in rural areas with no grid power. Batteries had to last 8+ years without replacement, operate at +45°C ambient, and integrate with NB-IoT communication modules.

Our Solution

We designed 3.6V 19Ah Li-SOCl₂ primary battery packs with ultra-low self-discharge PCM (<1%/year), NB-IoT module power-rail integration, and wide-temperature solder joints rated for -40°C to +85°C.

Voltage

3.6V (1S Li-SOCl₂)

Capacity

19Ah (68.4Wh)

Self-Discharge

<1% per year

Communication

NB-IoT module rail

Temp Range

-40°C to +85°C

Projected Life

8+ years

CEUN38.3RoHSZero battery replacements in 3 years of deployment. Projected 8+ year field life confirmed by accelerated aging tests. Utility expanded to Tanzania and Uganda.

Battery Systems for 18650 Li-ion Cells

18650 Li-ion Cell 2000mAh — EXW $0.80/pcs 18650 Li-ion Cell 2600mAh — EXW $1.20/pcs 18650 Li-ion Cell 3000mAh — EXW $1.60/pcs 18650 Li-ion Cell 3500mAh — EXW $2.20/pcs Custom Li-ion Battery Pack 21700 High-Energy Li-ion Pack

FAQ

Common Questions about 18650 Li-ion Cells Battery Systems

What is the difference between 2000mAh, 2600mAh, 3000mAh, and 3500mAh 18650 cells?

The capacity directly determines runtime — a 3500mAh cell stores 75% more energy than a 2000mAh cell. Higher capacity cells typically use denser NMC cathode materials. For pack assembly, never mix different capacities in the same series string, as this causes imbalance and premature failure.

Can I use these cells to build a custom battery pack?

Yes. Our 18650 cells are designed for spot-welding assembly into 2S–14S custom battery packs. We recommend using 0.15–0.2mm pure nickel strip and a battery management system (BMS) for any multi-cell pack. All cells within a pack must be from the same batch with matched capacity and internal resistance.

Are these cells certified for international air freight?

Yes. Every batch carries UN38.3 test summary and MSDS documentation, meeting IATA and ICAO requirements for lithium-ion cell air transport. We provide compliant packaging with hazard labels and shipper declarations for all international orders.

What is the minimum order quantity and lead time?

Sample MOQ is 100 pcs with a 3–5 day lead time from our Foshan factory. Mass production MOQ is 1,000 pcs with a 7–15 day lead time. For orders above 50,000 pcs, contact our sales team for dedicated production scheduling and volume pricing.

Do you offer flat-top and button-top terminal options?

Yes. We supply both flat-top cells (for spot-welding pack assembly) and button-top cells (for spring-contact devices like flashlights). Please specify your terminal requirement when ordering. Button-top cells add approximately $0.02/pcs to the base price.

What payment terms do you accept?

We accept T/T (Telegraphic Transfer / Wire Transfer) for all 18650 cell orders. Standard terms are 30% deposit before production and 70% balance before shipment. For established customers with order history, we offer net-30 terms upon credit approval.

Ready to Design Your 18650 Li-ion Cells Battery System?

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18650 Li-ion CellsDirect from Factory