Differentiator 1 — Cell Selection by Application Priority
We review whether your project needs high-capacity cells, high-discharge cells, long-cycle cells or safety-focused cylindrical cells before defining the pack configuration.
Custom 18650 & 21700 Cylindrical Battery Pack Manufacturer
Compact cylindrical lithium-ion packs engineered for mobility, portable equipment, industrial instruments and professional tools.
From cell selection and BMS configuration to assembly, testing and export documentation — handled in one engineering workflow.
Send your voltage, runtime target, current load and battery space. Our engineering team will review your pack requirements within 1 working day.
Traceable Cell Sourcing for 18650 / 21700 Packs
Cell brand and model selection is reviewed per project based on traceable sourcing, discharge current, capacity target, lead time, certification pathway, cost structure and customer approval.
Why Engineering Teams Choose PackForge
Custom 18650 and 21700 battery packs are not only about choosing a cell. OEM buyers need traceable sourcing, correct S/P structure, BMS protection, connector planning, thermal review, testing and export documentation under one controlled workflow.
Differentiator 2 — Series-Parallel Structure Review
Pack voltage, capacity, output current and available equipment space are reviewed together before defining the series-parallel structure.
Differentiator 3 — BMS and Protection Planning
BMS rating, over-current protection, temperature sensing, balancing, charge limits and communication options are reviewed around real load conditions.
Differentiator 4 — Connector, Harness and Enclosure Fit
Connector type, cable routing, strain relief, shrink wrap, holder, bracket or enclosure configuration are reviewed before sample assembly.
Differentiator 5 — Testing and Export Documentation
Capacity verification, charge / discharge testing, BMS protection checks, UN38.3, MSDS / SDS and Class 9 DG shipping requirements are reviewed before shipment planning.
Differentiator 6 — Traceability and Inspection Support
Cell batch information, BMS records, assembly date, test records and pre-shipment inspection can be reviewed for batch projects according to the agreed quality control process.
18650 vs 21700: Which Cell Format Fits Your Project?
Both 18650 and 21700 cells can be used for compact lithium battery packs. The better choice depends on energy target, discharge current, pack size, cell availability, cost structure and certification path.
Choose 18650 when:
- Your device has limited internal space
- You need mature cell availability and flexible layout
- You need a compact embedded pack
- Your project uses existing 18650-based mechanical space
- You need more layout flexibility in a narrow or irregular enclosure
Choose 21700 when:
- You need higher energy per cell
- You want fewer cells for the same energy target
- Your pack can accept a slightly larger cell diameter and length
- You need higher-capacity mobility or professional tool packs
- You are developing a new pack structure instead of replacing an old one
18650 cells are often preferred for compact and mature pack layouts, while 21700 cells can reduce cell count and improve energy per cell in suitable designs. Final selection should be based on load profile, space limit, thermal behavior, sourcing and certification requirements.
Pack Types We Manufacture
Different B2B projects require different cylindrical battery pack structures. PackForge reviews pack type based on voltage, capacity, discharge current, cell format, BMS, connector, enclosure and installation requirements.
Pack Type 1 — Compact Embedded & Custom Enclosure Packs
18650 / 21700 packs designed for compact equipment spaces where battery dimensions, wiring, insulation, connector layout and enclosure fit must match the device structure.
Typical project configuration:
- 2S–7S compact packs
- 18650 or 21700 cell format
- Fuel gauge optional
- Low-profile cable harness
- Shrink wrap, holder, bracket or custom enclosure
Pack Type 2 — High-Energy Mobility Packs
Cylindrical lithium packs for e-scooters, mobility equipment, service carts and light electric platforms where runtime and stable output need to be balanced.
Typical project configuration:
- 10S / 13S / 20S project-based structures
- 21700 preferred when space allows
- Smart BMS optional
- Charge / discharge connector planning
- Fixed or removable pack structure
Pack Type 3 — High-Discharge Tool & Equipment Packs
Battery packs for professional tools, industrial service equipment and high-current portable devices where peak current and heat behavior need to be reviewed.
Typical project configuration:
- 5S / 6S / 7S structures
- High-discharge 18650 or 21700 cells
- High-current BMS
- Temperature sensing
- Nickel strip and busbar review
Pack Type 4 — Removable / Swappable Battery Packs
Structured cylindrical packs for devices where the battery may be removed, charged separately or replaced during field operation.
Typical project configuration:
- Pack casing or plastic holder
- Locking mechanism
- Connector cycle life
- User handling safety
- Charging dock review
Engineering, Manufacturing & Quality Control
PackForge manages cylindrical lithium pack development through a controlled workflow covering cell selection, S/P structure, cell matching, interconnect design, BMS integration, testing and export documentation.
Pack Engineering & Cell Matching
We review cell model, series-parallel structure, discharge current, available space, BMS rating, connector layout and enclosure configuration before sample build.
Cell matching note:
Cells are grouped before assembly based on project-defined consistency requirements. Typical review targets may include capacity, internal resistance and open-circuit voltage to support pack-level balance behavior and cycle life.
Pack Assembly Process
Pack assembly is reviewed around welding method, interconnect material, insulation, cell holder, cable harness, connector layout and thermal behavior.
Professional process note:
Spot welding or laser welding can be reviewed per project based on cell type, interconnect material, target current and production process. Pure nickel, nickel-plated steel, fish paper insulation, holders and protective spacing are selected according to electrical and mechanical requirements.
Testing, Certification & Export Documentation
Each custom cylindrical battery pack can be checked against agreed electrical, mechanical and shipment requirements before delivery. Typical checks may include cell voltage verification, internal resistance review, capacity testing, charge / discharge testing and BMS protection verification before shipment.
Documentation support:
- UN38.3 transport test documentation
- MSDS / SDS
- Class 9 DG shipping documents
- Battery labels and carton marking
- IEC 62133-2 testing coordination when required
- UL 2054 pack-level testing support, based on UL 1642-certified cells
- CE / UKCA / PSE / KC documentation discussion
- RoHS / REACH declaration support
Reference Configurations for 18650 / 21700 Battery Pack Projects
The configurations below are reference specifications for early project discussion. Final voltage, capacity, BMS, connector, enclosure, testing and documentation scope depend on the application, load profile, space limit and destination market.
| Project Type | Nominal Voltage | Example Structure | Recommended Cell Type | Energy Range (Wh) | BMS Configuration | Engineering Notes |
|---|---|---|---|---|---|---|
| Compact handheld device | 7.2V / 7.4V | 2S2P / 2S3P | 18650 energy-focused cells | 25–45Wh | Protection board, fuel gauge optional | Embedded pack, low-profile harness |
| Industrial instrument pack | 10.8V / 11.1V | 3S2P / 3S3P | 18650 or compact 21700 | 45–90Wh | 3S BMS, temperature sensing | Compact enclosure, stable output |
| Field inspection equipment | 14.4V / 14.8V | 4S2P / 4S3P | 18650 high-capacity cells | 70–150Wh | Smart BMS optional | Removable or embedded pack |
| Professional tool pack | 18V / 18.5V | 5S2P / 5S3P | High-discharge 21700 or 18650 | 90–250Wh | High-current BMS, thermal review | Heat behavior, nickel strip review |
| 24V-class equipment pack | 25.2V / 25.9V | 7S3P / 7S4P | 21700 preferred when space allows | 250–550Wh | BMS with current and temperature protection | Equipment-side DC power |
| 36V mobility pack | 36V / 37V | 10S4P / 10S5P | 18650 or 21700 | 500–900Wh | Smart BMS optional | Fixed or removable pack |
| 48V mobility / service cart pack | 46.8V / 48.1V | 13S4P / 13S6P | 21700 preferred for higher energy | 750–1,500Wh | BMS with over-current and temperature protection | Connector, casing, charger matching |
| 72V project-based pack | 72V / 74V | 20S4P / 20S6P | 21700 high-capacity or high-discharge cells | 1,300–2,500Wh | Smart BMS, communication optional | Higher voltage safety and export review |
From Inquiry to Batch Production
A controlled project workflow helps reduce specification drift between the first sample, pilot batch and mass production.
01
Inquiry & NDA
Same day to 1 working day.
We review your application, voltage, runtime target, current load, battery space, connector requirement and documentation needs. NDA can be signed before drawing exchange when required.
02
Engineering Review
1–3 working days after complete project information.
Our engineering team completes the pack-level technical review and prepares clarification questions, design risks or alternative options for customer confirmation before quoting.
03
Preliminary Pack Specification & Quote
2–5 working days depending on technical complexity.
We prepare a preliminary pack specification and quotation. Cell sourcing path, BMS configuration, mechanical scope, testing items and required export documents are confirmed in writing.
04
Sample Build
3–5 weeks after specification confirmation.
Samples are built according to the confirmed specification, depending on BMS customization, enclosure complexity and cell availability. Each sample is checked before shipping.
05
Validation Testing
Customer-side validation depends on the project.
The customer validates fit, runtime, output, charging behavior, connector layout, communication and equipment-side compatibility. PackForge supports iteration before pilot batch.
06
Pilot Batch
4–6 weeks after sample approval.
Pilot batch production follows the approved sample specification and helps confirm production consistency before larger orders. Process records and batch test data are documented.
07
Batch Production & Export Delivery
Confirmed per project.
Batch production runs against the locked specification. Pre-shipment inspection, export documentation, packaging and logistics handover are coordinated according to the shipping schedule.
Lead Time
Typical sample lead time: 3–5 weeks after specification confirmation.
Pilot batch lead time: 4–6 weeks after sample approval.
Mass production lead time: confirmed per project based on cell availability, BMS, enclosure, quantity and certification scope.
MOQ
MOQ is reviewed per project based on cell model, BMS configuration, enclosure requirement, connector customization and documentation scope.
Sample orders and pilot batches can be reviewed before mass production. Pilot batch quantity is reviewed on a project-based basis after engineering review.
What You'll Receive
Standard deliverables:
- Physical battery pack samples
- Preliminary pack specification
- Sample test data: capacity, internal resistance, charge / discharge behavior
- Basic electrical test summary
- BMS parameter summary
- Connector and cable harness information
Project-based deliverables:
- Pack-level dimensional drawing
- Photo documentation of sample build
- UN38.3 / MSDS / SDS export documentation
- Export documentation review path
Anonymous 18650 / 21700 Project Highlights
The examples below show typical cylindrical lithium battery pack projects PackForge is set up to support for OEM/ODM customers. Customer names are withheld under NDA.
Project Highlight 1 — 48V Service Cart Battery Pack
Application:
Service cart / light mobility platform
Customer Location:
Europe
Configuration:
13S6P cylindrical lithium battery pack
Cell Format:
21700 high-capacity cells
Energy Range:
approx. 1,100–1,300Wh
BMS Configuration:
Smart BMS with RS485 communication
Pack Structure:
Fixed pack with charge / discharge connector planning
Documentation:
UN38.3, MSDS / SDS, CE pathway discussion
Production Stage:
Pilot batch validated before repeat production
Key Challenge:
Charger matching, peak current behavior, connector layout and vibration exposure
Project Highlight 2 — Professional Tool Battery Pack
Application:
Professional service tool battery pack
Customer Location:
North America
Configuration:
5S3P cylindrical lithium battery pack
Cell Format:
High-discharge 21700 or 18650 cells
Energy Range:
approx. 120–220Wh
BMS Configuration:
High-current BMS with temperature sensing
Pack Structure:
Removable pack with rugged housing and user handling review
Documentation:
UN38.3, MSDS / SDS, battery label support
Production Stage:
Sample validation followed by pilot batch planning
Key Challenge:
Peak current load, heat behavior, nickel strip selection and casing strength
Project Highlight 3 — Industrial Instrument Battery Pack
Application:
Portable industrial instrument
Customer Location:
Southeast Asia
Configuration:
4S3P cylindrical lithium battery pack
Cell Format:
18650 high-capacity cells
Energy Range:
approx. 100–160Wh
BMS Configuration:
Smart BMS optional, fuel gauge review when required
Pack Structure:
Compact embedded pack with low-profile cable harness
Documentation:
UN38.3, MSDS / SDS, transport energy classification review
Production Stage:
Sample build and equipment-side validation
Key Challenge:
Compact battery space, runtime target, cable routing and enclosure fit
Project Highlight 4 — Field Equipment Power Module
Application:
Portable field equipment power module
Customer Location:
Australia / New Zealand
Configuration:
7S4P cylindrical lithium battery pack
Cell Format:
21700 cells preferred when enclosure space allows
Energy Range:
approx. 350–550Wh
BMS Configuration:
BMS with over-current and temperature protection
Pack Structure:
Case-mounted pack with output connector and strain relief
Documentation:
UN38.3, MSDS / SDS, Class 9 DG shipping support
Production Stage:
Engineering review and pilot batch preparation
Key Challenge:
Field charging, output connector durability, transport labeling and packaging consistency
Frequently Asked Questions
Common questions from OEM and ODM customers reviewing 18650 / 21700 battery pack projects.
Yes, in most cases. We can review customer-supplied cells or specified cell models against the project's electrical, mechanical and certification requirements. We will share our review notes before committing to assembly, including risks related to cell datasheet limits, BMS matching and warranty scope.
Yes. NDA can be signed before any technical drawing, BMS firmware specification, enclosure file or confidential project information is shared. Customer-provided NDA templates are accepted after legal review, or we can provide a standard mutual NDA for project use.
Engineering iteration based on validation feedback is part of our sample development scope. We review test data, identify root cause, propose adjustments to cell selection, BMS parameters, mechanical fit or assembly process and rebuild updated samples. Iteration count and cost responsibility are confirmed in the project agreement before sample build.
Cell availability is reviewed at the start of every batch. If the original cell becomes unavailable, restricted or significantly delayed, we propose verified alternatives with comparable electrical and certification status. Specification change is communicated in writing and confirmed with the customer before production restart.
We coordinate certification testing with accredited third-party laboratories including UN38.3, IEC 62133-2, UL 2054, CE, UKCA, PSE, KC, RoHS and REACH. Sample preparation, document submission and laboratory communication are handled by our engineering team. Final certification scope, testing cost and timeline are confirmed per project before sample submission.
For a meaningful quotation, we typically need: application type, nominal voltage, capacity or runtime target, continuous and peak discharge current, battery space or mechanical drawing, connector requirement, charging method, target market, estimated annual quantity and required documentation. Incomplete inquiries can still be reviewed, but specification gaps will need to be closed before a firm quote.
Yes. On-site visits, customer-arranged third-party audits and video walkthroughs of pack assembly, testing and QC areas can be arranged for serious projects after initial technical alignment. Visit scheduling is coordinated with project timeline and ongoing production confidentiality.
Pack-level workmanship warranty and post-shipment support are confirmed per project based on application, duty cycle, operating conditions, target market and agreed technical scope. We support issue review through test data, photos, BMS records, returned sample analysis when required and corrective action planning for future batches.