Cylindrical Lithium Cells
Cylindrical cells remain the right answer whenever you need high discharge rates, standardised holders or a pack shape no prismatic cell can fill — and CMX Battery builds the pack around them, holder, strip, BMS and housing included.
Overview
CMX Battery supplies 18650, 21700, 26650 and 32700 cylindrical lithium cells in both power and energy grades. Cylindrical form factors handle high discharge currents and mechanical shock better than prismatic cells and drop into standard holders and spot-weld layouts, which is why they dominate power tools, e-bike, portable and specialty packs. We grade cells for your application, then design and weld the pack — holder, nickel strip, BMS and enclosure — so you receive a tested assembly, not loose cells.
Key specifications
| Specification | Value | Why it matters |
|---|---|---|
| Sizes | 18650 / 21700 / 26650 / 32700 | Each size trades capacity against discharge rate and form factor. |
| Grades | Power (high C-rate) and energy (high capacity) | Pick the grade from the load profile: bursts vs runtime. |
| Chemistry | LiFePO4 or NMC per application | LFP for safety/cycle life; NMC where energy density or cold performance leads. |
| Typical capacity | 18650 ≈2.5–3.5Ah; 21700 ≈4.0–5.0Ah | 21700 packs more energy in a similar diameter. |
| Assembly | Spot-welded packs with BMS and enclosure | We build the pack, not just the cells. |
Typical applications
- Power tools and e-mobility: High C-rate cylindrical packs.
- Portable power stations: 21700-based energy packs.
- Medical and instrumentation: Small, shock-resistant banks.
- OEM custom packs: Holder, strip, BMS and housing designed to spec.
How to specify & buying guide
- Choose power vs energy grade from your peak C-rate — do not over-spec capacity at the cost of discharge ability.
- Tell us the pack voltage and shape; we design holder, nickel strip and spot-weld layout, not just supply cells.
- Specify the BMS topology (series/parallel, communication) so the pack arrives protected and balanced.
- Require incoming-grade matching data for the cells we weld into your pack.
Engineering & manufacturing at CMX Battery
CMX Battery grades every LiFePO4 prismatic and cylindrical cell on capacity, internal resistance and self-discharge before it enters a pack. We ship matched batches with per-cell test data keyed to serial numbers, so your production line is not sorting cells on arrival. Bulk cells, welded modules and complete packs are all built under the same quality system.
Certifications & compliance
- UN38.3 — Mandatory lithium battery transport test (altitude, thermal, vibration, shock, external short). Required for any cross-border shipment.
- IEC62133
- MSDS — Material safety data sheet for handling and shipping.
- RoHS — Restriction of hazardous substances in the battery and BMS.
- CE — EU declaration of conformity for the applicable directives.
Frequently asked questions
Do you build the pack or just sell cells?
Both. We supply loose graded cells and build complete packs with holder, nickel strip, BMS and enclosure.
Which chemistry do you recommend for portable?
LiFePO4 for safety and cycle life where energy density allows; NMC where weight or cold performance leads.
Can you match a specific C-rate?
Yes — tell us the continuous and peak current and we select the power or energy grade accordingly.
What documentation ships?
Cell test data plus pack assembly and BMS documentation, UN38.3 and MSDS.
Related products & resources
More in this series
- Lithium Battery Products
- LiFePO4 Cells
- LiFePO4 Battery Modules
- LiFePO4 Battery Management Systems (BMS)
- Sodium-Ion Batteries
- 12V LiFePO4 Batteries
- 24V LiFePO4 Batteries
- 48V LiFePO4 Batteries
- Residential Energy Storage Systems
- Commercial & Industrial Energy Storage
- Containerised BESS
- Portable Power Stations
- RV Lithium Batteries
- Marine LiFePO4 Batteries
- Golf Cart Lithium Batteries
- Deep Cycle LiFePO4 Batteries
- Trolling Motor Lithium Batteries
- Forklift Lithium Batteries
- Self-Heating LiFePO4 Batteries
- Low Temperature Lithium Batteries
- Hybrid Inverters
- Inverter Chargers
- MPPT Solar Charge Controllers
32700, 32650 and 60140: the formats we build packs around
The size names above are family names, not specifications. A quotation only becomes comparable once the format geometry, the capacity grade, the continuous discharge rate and the cycle-life protocol are on the table together, so the figures below are taken from our published cell datasheets rather than from the format name.
| Format | Diameter × height | Nominal voltage | Capacity | Continuous discharge | Cycle life |
|---|---|---|---|---|---|
| 32700 | Ø32.2 ± 0.3 × 70.5 ± 0.3 mm | 3.2 V | 6.0 Ah | 5C / 30 A | ≥3000 @ 1C / 100% DOD |
| 32650 | Ø32 × 65 mm | 3.2 V | 5 Ah | Quoted per project | Quoted per project |
| 60140 | Ø60 × 140 mm | 3.2 V | 50 Ah | 1C / 50 A | >4000 @ 80% DOD |
32650 and 32700 share the 32 mm diameter and differ by 5 mm in length, so a holder tooled for one will not accept the other. The 60140 belongs to a different class: roughly seven times the volume of a 32700 for over eight times the capacity, which is why builders move up to it once weld count rather than cell count becomes the constraint. 18650, 21700 and 26650 cells are supplied in the power and energy grades and the capacity bands listed above.
Cylindrical or prismatic: how to choose
Both formats are built in the same plant from the same graded cells, so the choice is a design decision rather than a sourcing one. Three questions settle it in most projects.
| Cylindrical | Prismatic | |
|---|---|---|
| Best when | the pack is sized by power, or the enclosure shape suits round cells | the pack is sized by energy and sits in a rack, cabinet or container |
| Typical duty | power tools, e-mobility, portable packs, high-rate UPS strings | home ESS, C&I BESS, telecom, forklift and stacked packs above roughly 5 kWh |
| What it costs you | more welds and more BMS sense lines per kWh | lower continuous C-rate per cell, and the pack needs compression and busbar design |
If the load profile is a short burst at high current, start cylindrical. If it is a long, shallow discharge night after night, start prismatic. The prismatic LiFePO4 cells range covers 50 Ah to 314 Ah, and the large square prismatic cells page covers the high-capacity end of the same programme.
What to send with a cylindrical cell RFQ
Six items turn a list of quotes into a list of comparable quotes:
- Format plus tolerance. Our 32700 is Ø32.2 ± 0.3 mm × 70.5 ± 0.3 mm. If your holder is tooled to a nominal 32.0 mm, say so before quoting.
- Capacity grade and its test condition. Capacity measured at 0.2C to 2.0 V is not the same figure as capacity measured at 1C; state which one you are buying.
- Continuous and pulse current. Our 32700 build is 5C / 30 A continuous, 6C / 36 A for short duration and 60 A for a 3-second pulse, charged at 1C to 3.65 V.
- Cycle-life protocol. C-rate, depth of discharge and end-of-life threshold. 3000 cycles at 100% DOD is a harder test than a 4000-cycle figure quoted at 80% DOD, so the two cannot be placed side by side.
- AC internal resistance at 1 kHz, per batch — 5.5–6.5 mΩ on our 6 Ah 32700 build.
- Volume, destination port and documents. UN38.3, MSDS, and any IEC 62133, IEC 62619 or UL evidence your customer’s approval process requires.
From cell to pack: the voltage maths
LiFePO4 nominal voltage is 3.2 V per cell, so series count sets the voltage and parallel count sets the capacity. 4S is 12.8 V, 8S is 25.6 V and 16S is 51.2 V — the nominal voltage behind the “48 V” label that inverters and chargers are specified against. A 16S1P string of 6 Ah 32700 cells is therefore a 51.2 V 6 Ah module; sixteen strings in parallel take it to a 51.2 V 96 Ah pack. Built around the 50 Ah 60140 cell, the same voltage class and a round 100 Ah needs only 16S2P. That gap — 256 cells against 32 for one pack — is the trade-off that decides most cylindrical-versus-larger-format specifications. For a finished pack at that rating, see the 48 V 100 Ah server rack LiFePO4 pack.
Cylindrical cell questions
What is the difference between a 32700 and a 32650 cell?
The diameter is identical at 32 mm; the length differs by 5 mm, 70 mm against 65 mm. A holder, spacer or welding jig tooled for a 32650 will not accept a 32700. Both are 3.2 V LiFePO4.
Why is a 51.2 V battery sold as 48 V?
51.2 V is 16 LiFePO4 cells in series at 3.2 V nominal. Inverters and chargers are specified against the “48 V” lead-acid-equivalent class, so both labels describe the same string.
How many cylindrical cells does a 51.2 V 100 Ah pack need?
With 6 Ah 32700 cells, 16 in series and 16 strings in parallel: 256 cells for 96 Ah. With 50 Ah 60140 cells the same target takes 16S2P, 32 cells, for 100 Ah.
What is the minimum order for a cylindrical cell programme?
MOQ depends on the format, the grade and whether you take cells loose or as finished packs. Send your annual volume and destination port and our team will confirm the figure together with the quotation.
Request a quote
Send us your voltage, capacity, dimensions, certification target and annual volume. Our engineering team returns a proposal within three working days. Start your RFQ or review our custom pack capabilities.