How OEMs Customize LiPo Batteries for Unique Applications
In the hyper-competitive landscape of modern product development, the “off-the-shelf” solution is rarely the optimal one. Whether you are engineering a next-generation medical wearable that must curve around a patient’s wrist, or a high-performance industrial drone that requires a precise center of gravity, the battery often dictates the physical and functional limits of the device. Original Equipment Manufacturers (OEMs) face a critical choice: compromise the device design to fit a standard battery, or customize the battery to fit the vision.
At Hanery, we believe that power should adapt to innovation, not the other way around. As a premier Chinese manufacturer specializing in polymer lithium batteries, 18650 packs, and Lithium Iron Phosphate (LiFePO4) solutions, customization is the core of our business. We do not just sell energy; we engineer solutions. Our R&D teams work side-by-side with global engineers to transform rough concepts into sophisticated, mass-producible power systems.
This comprehensive guide takes you behind the curtain of the OEM customization process. We will explore every lever an engineer can pull—from physical dimensions and chemical formulations to smart Battery Management Systems (BMS) and lead-wire configurations—to create a battery that is as unique as the product it powers.
Table of Contents
Custom Dimensions: Breaking the Rectangular Mold
The most immediate driver for customization is physical space. Standard batteries come in fixed sizes, often creating “dead space” inside a device housing or forcing the device to be bulkier than necessary.
The Freedom of Stacking Technology
Unlike cylindrical cells (like the 18650) which are rigid steel cans, Lithium Polymer (LiPo) cells utilize a flexible aluminum laminate pouch. Hanery employs advanced Z-Stacking (Lamination) technology. Instead of winding the electrodes into a jelly roll, we stack sheets of anode, cathode, and separator.
- Aspect Ratio Flexibility: We can manufacture cells that are long and ultra-narrow (e.g., for a smart pen), square and flat (for a tracker), or even L-shaped (to fit around a circuit board).
- Thickness Control: We can adjust thickness in increments of 0.1mm. If your device cavity is 4.5mm deep, we can design a 4.2mm cell (leaving room for swelling), maximizing capacity compared to a standard 3.0mm or 5.0mm cell.
Maximizing Volumetric Efficiency
By customizing the dimensions (Length x Width x Thickness), OEMs can achieve 95% to 98% volumetric efficiency.
- Example: A circular smartwatch housing using a square off-the-shelf battery wastes about 30% of the internal volume. By customizing a D-shaped or semi-circular battery, Hanery helps OEMs reclaim that space, increasing battery life by 25-30% without changing the external size of the watch.
Tailored Capacity and Voltage: The Energy Matrix
Once the physical size is defined, the next step is determining the electrochemical characteristics: Capacity (mAh) and Voltage (V).
The Capacity/Voltage Trade-Off
Lithium batteries operate on a balance of active material.
- Higher Capacity: By using high-density cathode materials (like Lithium Cobalt Oxide or High-Nickel NMC), we can pack more milliamp-hours into the cell.
- Higher Voltage: Standard LiPo is 3.7V nominal / 4.2V max. Hanery offers High-Voltage (LiHv) customization. By tweaking the electrolyte and cathode coating, we can safely charge to 4.35V or 4.40V. This provides a higher nominal voltage (3.8V or 3.85V) and effectively boosts energy density by 10-15%.
Series and Parallel Configurations (S/P)
For larger devices, single cells are combined into packs.
- Series (S): Increases Voltage. A 3S pack (11.1V) is ideal for driving motors in drones or vacuums.
- Parallel (P): Increases Capacity and Current capability. A 1S2P pack (two cells in parallel) doubles the runtime and the max amps the pack can deliver.
Hanery Engineering Insight: When customizing a pack, we perform Cell Matching. We grade thousands of cells to find “twins” with identical internal resistance and capacity. This ensures that when built into a pack, the cells age symmetrically, significantly extending the pack’s lifespan.
Lead-Wire and Connector Choices: The Critical Interface
How the power gets from the battery to the device is often overlooked, yet it is a common point of failure. Customization allows OEMs to spec the perfect connection.
Wire Gauge (AWG) Selection
The wire thickness must match the current draw.
- Low Current (Sensors): 24 AWG or 26 AWG is sufficient, flexible, and lightweight.
- High Current (Drones/Tools): 10 AWG or 12 AWG silicone wire is required to prevent voltage drop and melting. Silicone insulation is preferred for its flexibility and heat resistance (up to 200°C).
Connector Types
We offer a vast library of connectors, or we can source specific ones requested by the OEM.
- JST-PH / JST-XH: Standard for small electronics and balance leads.
- Molex / TE Connectivity: Common in industrial and automotive applications for secure, locking connections.
- XT60 / XT90 / EC5: The gold standard for high-amperage RC and robotics applications.
- Custom PCBs: For ultra-compact designs, we can replace wires entirely with a rigid-flex PCB or gold-plated contact pads directly on the battery protection board.
Strain Relief and Length
We customize the wire length to the millimeter. Excess wire creates clutter and weight; too little wire creates tension. We also add strain relief glues or tapes at the solder points to prevent wires from snapping during vibration or installation.
PCM/BMS Customization: The Brain of the Battery
The Protection Circuit Module (PCM) or Battery Management System (BMS) is the safety gatekeeper. Customizing this board is critical for integrating the battery with the device’s logic.
Physical Layout
The BMS doesn’t have to sit on top of the battery.
- Side Mounting: For thin devices, we can mount the BMS on the side of the cell.
- Flying Leads: The BMS can be integrated into the wiring harness.
- Device Integration: In some cases, the OEM integrates the protection logic onto their main motherboard, and we supply the bare cell (though Hanery advises keeping a basic PCM on the cell for shipping safety).
Smart Communication Protocols
For high-end applications, a “dumb” protection circuit isn’t enough. We customize “Smart BMS” solutions using Fuel Gauge ICs (like those from Texas Instruments or Maxim).
- SMBus / I2C: Allows the battery to “talk” to the device, reporting precise percentage (SoC), cycle count, temperature, and “Time to Empty.”
- CAN Bus: Used in industrial and automotive robotics for robust communication in noisy electrical environments.
Safety Threshold Tuning
We program the protection parameters to match the device needs.
- Over-Current: If your motor has a high startup spike (inrush current), we program a “delay timer” into the short-circuit protection so the battery doesn’t cut off during normal startup.
- Temperature: We can set custom thermal cutoffs (e.g., stop charging at 45°C) to match the environmental constraints of the product.
Rapid Prototyping Workflow: From Concept to Sample
Speed to market is essential. Hanery’s OEM workflow is designed to move from a napkin sketch to a physical sample in weeks, not months.
Step 1: Requirement Analysis
Our engineers meet with the OEM to define the “Power Budget”: Voltage, Capacity, Max Dimensions, and Max Current Draw.
Step 2: 3D Modeling and Drawing
Within 2-3 days, we provide a technical drawing (Datasheet) and a 3D CAD model. This allows the OEM to verify the fit inside their virtual device assembly before any metal is cut.
Step 3: Tooling and Sample Production
- Custom Tooling: If a new size is needed, we create custom cutting dies and forming molds. This typically takes 10-15 days.
- Hand-Made Samples: For urgent testing, we can sometimes produce small batches of “hand-made” samples using existing tooling that is close in size, allowing the OEM to test electrical performance while waiting for the mechanical fit.
Step 4: Testing and Validation
Before shipping, samples undergo “Golden Sample” testing, including dimension checks, capacity grading, and drop testing. The typical lead time from design approval to sample delivery is 20-25 days.
Certification Planning: The Passport to Global Markets
A custom battery cannot be sold legally without certification. Navigating this regulatory maze is part of Hanery’s value-add.
Pre-Compliance Consulting
We design the battery with certification in mind.
- UN 38.3: Mandatory for shipping. We ensure the cell construction can pass the vibration, shock, and altitude simulation tests.
- IEC 62133 / UL 1642: Safety standards for consumer electronics. We use certified raw materials (separators, electrolytes) that are pre-approved to speed up the final pack certification.
Managing the Process
Hanery works with third-party labs (like TUV, Intertek, SGS) to manage the testing process.
- Cost Efficiency: Certification is expensive (thousands of dollars). We advise OEMs on “Series Certification”—certifying a range of batteries based on one test model—to save costs on product families.
Cycle-Life Customization: Longevity vs. Density
Not all applications need the same lifespan. A disposable medical patch needs to last 1 week. A solar street light needs to last 5 years.
Electrolyte Tuning
- High Density / Short Life: For consumer drones where flight time is everything, we use aggressive electrolyte additives that maximize capacity but might limit life to 300 cycles.
- Long Life / Lower Density: For industrial tools, we use stable electrolyte formulas and thicker separators. This might reduce capacity by 5% but extend cycle life to 800 or 1000 cycles.
Electrode Materials
We can customize the cathode material blend.
- LCO (Lithium Cobalt Oxide): Standard for consumer tech (500 cycles).
- NMC (Nickel Manganese Cobalt): Balanced performance.
- LiFePO4: For extreme longevity (2000+ cycles) where weight is less critical.
High-Discharge Custom Solutions
For robotics and power tools, energy delivery speed (C-Rating) is the priority.
Tab Design
Standard tabs create a bottleneck for high current.
- Multipole Tabs: We can customize the cell with multiple positive and negative tabs emerging from the stack. This reduces internal resistance and heat.
- Wide Tabs: We increase the width and thickness of the nickel/aluminum tabs to handle currents of 50A, 100A, or more.
Thermal Management
High discharge generates heat. We can design the pack with integrated thermal gaps between cells or incorporate Phase Change Materials (PCM)—a wax-like substance that absorbs heat—wrapping the cells to keep them cool during peak loads.
Robotics and Medical Custom Packs: Specialized Needs
Two sectors drive the most demanding customization requests: Robotics and Medical.
Robotics Customization
- Center of Gravity: Drones require balanced weight. We can split a battery pack into two distinct halves connected by a wire, allowing the OEM to mount them on either side of the drone chassis.
- Burst Power: Robotics motors stall and surge. We design the BMS to tolerate high transient spikes without tripping protection.
Medical Customization
- Reliability: Medical batteries cannot fail. We use “Grade A+” cells with tighter quality control tolerances.
- Redundancy: We design packs with dual protection circuits. If the primary BMS fails, a secondary passive fuse or thermal cutoff acts as a backup.
- Traceability: Every single cell is laser-marked with a unique serial number, allowing full traceability of raw materials back to the mine, a requirement for FDA compliance.
Hanery OEM Case Capabilities
To illustrate our capabilities, here is a summary of how we execute complex projects.
Project: The Smart Survival Watch
- Challenge: The client needed a battery that could curve around the wrist, operate in -30°C temperatures, and last for 3 days with GPS on.
- Hanery Solution:
- Shape: Designed a custom curved cell (R=45mm) to fit the wristband.
- Chemistry: Developed a “Low-Temperature” electrolyte formula capable of discharging at -40°C with 80% efficiency.
- Density: Used High-Voltage (4.35V) chemistry to squeeze 600mAh into a space that normally held 450mAh.
- Result: The product launched successfully, dominating the niche market for arctic explorers.
Chart: Customization Options Matrix
| Feature | Standard Option | Custom OEM Option | Benefit |
|---|---|---|---|
| Voltage | 3.7V / 4.2V | 3.8V / 4.35V (LiHv) | +15% Energy Density |
| Shape | Rectangular | D-Shape, Round, Curved | +30% Volume Use |
| Temp Range | -10°C to 60°C | -40°C to 80°C | Extreme Environment Use |
| Wire/Conn | PVC / JST | Silicone / Molex / Gold | Durability & High Current |
| BMS | Safety Only | Fuel Gauge (I2C/SMBus) | Precision Battery Data |
| Labeling | Hanery Brand | OEM Logo / Custom Warning | Branding & Compliance |
Frequently Asked Questions
What is the Minimum Order Quantity (MOQ) for custom batteries?
For minor customizations (connectors, wires, labels) on standard cells, the MOQ is low, typically 20,000 units. For fully custom cell dimensions (requiring new tooling), the MOQ is typically 50,000 to 100,000 units to amortize the tooling cost.
How much does custom tooling cost?
Tooling costs vary by size but generally range from $1,000 to $5,000 USD. This is a one-time fee. Once paid, the tooling belongs to the client and is used for all future production runs.
How long does the R&D design process take?
Typically, we can go from initial consultation to 3D drawing in 3 days. From drawing approval to physical sample delivery takes 20-25 days. Mass production lead time is usually 30-40 days.
Can Hanery replicate a discontinued battery from another brand?
Yes. If you can provide the physical dimensions and voltage/capacity specs (or send us a sample), our engineers can reverse-engineer the pack and build a compatible or improved replacement.
Do I own the Intellectual Property (IP) for my custom battery?
Yes. If you pay for the custom tooling and design NRE (Non-Recurring Engineering) costs, the design belongs to you. Hanery signs Non-Disclosure Agreements (NDAs) to protect your proprietary device information.
Can you customize the battery label?
Absolutely. We print custom labels with your logo, part number, regulatory marks (CE, UL), and warnings. This is standard for OEM clients.
What if my device needs a battery shape that doesn’t exist?
That is our specialty. We can manufacture “odd” shapes. However, extreme shapes may have slightly lower energy density than simple rectangles. Our engineers will simulate the design to tell you the feasibility and expected capacity.
How do you ensure safety in custom designs?
We perform a “Golden Sample” validation. We subject the custom prototype to crush, nail penetration, short circuit, and thermal shock tests. Mass production only begins after the custom design passes these safety benchmarks.
Can you integrate the charger into the battery?
Generally, the charging circuit is on the device side. However, for some applications (like USB-rechargeable batteries), we can integrate a miniature charging circuit and USB-C port directly onto the battery BMS.
Why should I choose Hanery over a generic trading company?
Hanery is a manufacturer, not a middleman. You speak directly to the engineers building your product. This ensures faster communication, lower costs (no middleman markup), and direct accountability for quality control.
Summary & Key Takeaways
Customizing a LiPo battery is not just about changing the size; it is about optimizing the very heart of your product. It allows OEMs to stop compromising and start innovating. By tailoring the chemistry, protection, and form factor, you can create a device that lasts longer, charges faster, and fits better than the competition.
- Fit for Purpose: Custom dimensions maximize volumetric efficiency, allowing for sleeker devices or larger capacities in the same footprint.
- Brain Power: Smart BMS customization enables advanced features like “Time-to-Empty” displays and precise health tracking.
- Speed to Market: Hanery’s rapid prototyping workflow ensures that a custom battery doesn’t become the bottleneck in your product launch.
- End-to-End Support: From the first CAD drawing to the final UN 38.3 shipping certification, we handle the complexity so you can focus on your device.
At Hanery, we are ready to be your engineering partner. Whether you are building the next million-unit consumer gadget or a specialized niche medical tool, our factory has the flexibility and expertise to power your vision.
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Contact Info
- info@hanery.com
- +86 13414472012
- https://www.hanery.com/
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