Custom Lithium Battery Packs – OEM Design, BMS Integration & Certified Manufacturing
Published by A&S Power | Battery Technology
Introduction
A custom lithium battery pack is more than just a collection of cells – it‘s a complete power solution designed to fit your device’s exact requirements. Whether you need a compact pack for a wearable device or a high-capacity pack for industrial equipment, the right battery pack ensures optimal performance, safety, and reliability.
At A&S Power, we manufacture custom lithium battery packs for OEM buyers worldwide. This guide covers everything you need to know about custom lithium battery packs – from design considerations and customization options to quality control and compliance.
For a complete overview of our custom battery capabilities, check out our full guide: Custom Lithium Polymer Battery – OEM/ODM Solutions for IoT, Wearables & Medical Devices.
What is a Custom Lithium Battery Pack?
A custom lithium battery pack is an assembly of multiple lithium cells configured in series, parallel, or series-parallel to achieve the desired voltage and capacity. The pack typically includes:
- Cells – Li-Polymer pouch or Li-Ion cylindrical cells
- BMS (Battery Management System) – Overcharge, over-discharge, short-circuit protection, and communication
- Connectors – Wire leads, JST, Molex, or custom connectors
- Encapsulation – Heat-sealed pouches, plastic housings, or custom-molded enclosures
- Labeling – OEM branding with your logo and product information
Why Choose a Custom Lithium Battery Pack?
Off-the-shelf batteries rarely fit the unique requirements of OEM applications. A custom battery pack offers:
| Benefit | Why It Matters |
|---|---|
| Custom dimensions | Fits your device‘s exact enclosure |
| Optimized capacity | Matches your target runtime |
| Custom voltage | 3.7V, 7.4V, 11.1V, or custom configurations |
| Built-in BMS | Overcharge, over-discharge, short-circuit protection |
| Custom connectors | JST, Molex, wire leads, or custom harnesses |
| OEM branding | Your logo and specifications on every pack |
| Global certifications | UL 1642 tested, CE, RoHS, UN38.3 |
Types of Custom Lithium Battery Packs We Manufacture
| Pack Type | Cell Type | Voltage Options | Typical Applications |
|---|---|---|---|
| Single-cell packs | Li-Polymer pouch | 3.7V | Wearables, TWS earbuds, IoT sensors |
| Multi-cell packs | Li-Polymer pouch | 7.4V, 11.1V, 14.8V | Medical devices, portable speakers, drones |
| 18650 packs | Cylindrical Li-Ion | 3.6V – 14.8V | Power tools, flashlights, e-bikes |
| High-capacity packs | Li-Polymer / 18650 | 3.7V – 14.8V | Portable power stations, industrial equipment |
Customization Options for Lithium Battery Packs
1. Cell Selection
We help you choose the right cell type (Li-Polymer or Li-Ion) and capacity for your application, balancing runtime, size, and cost.
2. Configuration
- Series (S): Increases voltage (e.g., 2S = 7.4V, 3S = 11.1V)
- Parallel (P): Increases capacity (e.g., 2P = double runtime)
- Series-Parallel: Both voltage and capacity customized
3. BMS Integration
- Overcharge, over-discharge, short-circuit protection
- Temperature monitoring with NTC thermistor
- Communication protocols: I²C, SMBus, CAN, HDQ
- Fuel gauge / State of Charge (SoC) reporting
4. Encapsulation
- Heat-sealed pouch wrapping – lightweight and compact
- Plastic housing – rigid protection
- Custom-molded enclosures – full mechanical integration
5. Connectors
- Wire leads with custom length and gauge
- JST, Molex, Anderson, XT60, or custom connectors
6. Labeling
- OEM branding with your logo
- Product specifications and safety markings
- Serial numbers and traceability codes
Applications for Custom Lithium Battery Packs
| Industry | Applications |
|---|---|
| Medical Devices | Patient monitors, diagnostic equipment, drug delivery systems |
| Wearable Devices | Smartwatches, fitness trackers, smart glasses, smart rings |
| IoT Sensors | Environmental monitors, asset trackers, smart home sensors |
| Consumer Electronics | TWS earbuds, Bluetooth speakers, portable chargers |
| Industrial Equipment | Handheld scanners, test equipment, portable tools |
| Portable Power | Power banks, portable power stations, emergency lights |
How to Choose the Right Custom Battery Pack
Step 1: Define your voltage and capacity requirements
Calculate your device‘s power consumption and runtime requirements to determine the optimal voltage and capacity.
Step 2: Consider physical constraints
Measure your device’s available space and determine the maximum dimensions for the battery pack.
Step 3: Evaluate BMS and communication needs
Does your device need basic protection or advanced communication (I²C, SMBus, CAN)?
Step 4: Consider compliance requirements
Identify the certifications needed for your target markets (UL, CE, RoHS, UN38.3).
Step 5: Evaluate supplier capabilities
Check the manufacturer‘s experience with custom packs, engineering support, and quality control processes.
Quality Control and Testing
| Test | Purpose |
|---|---|
| Open-circuit voltage (OCV) | Verifies cell voltage within specification |
| Internal resistance (ACIR) | Ensures consistent cell performance |
| Capacity testing | Confirms rated capacity |
| Cycle life testing | Validates longevity and durability |
| Safety testing | Overcharge, over-discharge, short-circuit tests |
| Visual inspection | Checks for physical defects |
✅ What A&S Power Offers: 100% final functional testing on every battery pack. Batch-level traceability for full accountability.
Frequently Asked Questions
1. What is the difference between a battery cell and a battery pack?
A cell is a single electrochemical unit. A pack is an assembly of multiple cells with a BMS, connectors, and encapsulation, ready to use in your device.
2. Can you customize the shape of a lithium battery pack?
Yes. Li-Polymer packs can be shaped to fit any enclosure – rectangular, stepped, curved, or ultra-thin. 18650 packs are cylindrical but can be configured in various series-parallel arrangements.
3. What is the minimum order quantity (MOQ) for custom battery packs?
MOQ depends on the complexity of the pack. For standard configurations, MOQ starts at 1,000-3,000 units. For fully custom designs, we can work with lower quantities for prototyping.
4. How long does sample development take?
Typical sample lead time is 2-4 weeks. Mass production takes 4-6 weeks after sample approval.
5. What certifications do you provide?
UL 1642 tested cells, CE, RoHS, UN38.3, and IEC62133. Full documentation with every order.
6. Do you ship globally?
Yes. We ship to North America, Europe, Asia, Australia, and beyond with full UN38.3 certification.
Custom Lithium Battery Packs from A&S Power
At A&S Power, we manufacture custom lithium battery packs for OEM buyers across multiple industries. From medical devices and wearables to IoT sensors and portable electronics, we deliver tailored solutions with safety and performance in mind.
- ✅ Custom dimensions and capacities
- ✅ Li-Polymer and Li-Ion cell options
- ✅ UL 1642 tested cells, CE, RoHS, UN38.3 certified
- ✅ OEM labeling and packaging
- ✅ Engineering support from concept to production