When you hear the term circular batteries or round batteries, you might think of small coin cells or cylindrical types. But there’s another powerful type worth knowing—LiPo circular batteries, also known as round LiPo batteries or even D-shaped polymer batteries. These compact energy sources are gaining popularity in many modern electronic devices because of their flexibility, performance, and customization potential.
Let’s explore what makes these round batteries so unique and why they might be the perfect fit for your next project.
1. What is a circular LiPo battery?
A circular LiPo battery is a lithium polymer battery with a round or curved shape. Unlike the traditional rectangular LiPo cells, these are designed in circular, semi-circular, or D-shaped forms. This unique design allows for more efficient use of space in devices that don’t conform to standard battery shapes.
These batteries still use the same basic chemistry—lithium-ion in a polymer electrolyte—but their round design opens up new possibilities for wearables, medical devices, smart rings, and more.
You might also see the term D-shaped LiPo battery. This usually refers to a half-circle or semicircle battery, designed to sit flush against the curved housing of a wearable device like a smartwatch or headset.
2. Advantages of circular LiPo batteries
So why would anyone choose a round battery over the more common rectangular shape? Turns out, there are plenty of good reasons:
- Space-Saving Design: Ideal for circular or irregular housings like rings, watches, or sensors.
- Customizable Shapes: Round, D-shaped, or semi-circular versions can be tailored for your application.
- Lightweight and Thin: Great for wearables and portable electronics where weight matters.
- Stable Voltage Output: LiPo chemistry provides consistent voltage delivery.
- Fast Charging: Many round batteries support rapid charging.
- High Energy Density: Packs a lot of power into a small space.
- Flexible Configurations: Series or parallel connections can modify voltage and capacity as needed.
These benefits make LiPo circular batteries perfect for small, power-hungry gadgets where every millimeter counts.
3. Size, shape, capacity, voltage – all customizable
One of the best things about LiPo circular batteries is how customizable they are.
- Diameter: Typically ranges from 10mm to 50mm, but can be tailored to fit any device.
- Thickness: Can be as thin as 1mm or thicker depending on power needs.
- Shape: Circular, half-moon, oval, or D-shaped.
- Capacity: From as low as 20mAh up to several hundred mAh.
- Voltage: Standard single-cell LiPo voltage is 3.7V, but higher voltages can be achieved by combining cells.
Because these batteries are often custom-built, working with the right supplier is crucial. That’s where Ufine Battery comes in.
Ufine Battery is a trusted Chinese manufacturer specializing in custom lithium polymer batteries, including round LiPo batteries. We offer a full range of cylindrical, ultra-thin, high-rate, and high-temperature LiPo batteries to match your exact needs.
👉 Contact us now at Ufine Battery to start your custom battery project.
4. Selecting a circular LiPo battery: 7 key considerations
Choosing the right LiPo circular battery requires more than just picking a size. Here are seven essential things to keep in mind:
1. Device Shape & Battery Fit
Make sure the battery’s diameter and thickness fit within your device’s housing. Measure carefully—millimeters matter.
2. Capacity Needs
How long does your device need to run before recharging? A higher mAh rating gives longer runtime but may increase size.
3. Voltage Requirements
Most circular LiPo batteries are 3.7V, but some applications require more. Know your device’s input voltage specs.
4. Discharge Rate (C-Rating)
Devices that draw high current need a higher C-rating to prevent voltage drops or overheating.
5. Safety Features
Look for batteries with built-in protection circuits (PCM/BMS) to avoid overcharge, over-discharge, and short circuits.
6. Battery Life (Cycle Count)
Check the number of charge/discharge cycles the battery supports. High-quality LiPo batteries often last 300–500 cycles or more.
7. Operating Temperature Range
If your device runs in hot or cold conditions, choose a battery with an appropriate temperature tolerance.
Working with a supplier like Ufine Battery ensures these specs are met precisely—because we build batteries tailored to your application.
5. What connector does a circular LiPo battery use?
The type of connector depends on the device and its power requirements. Here are some common options:
- JST Connectors (like JST-PH or JST-XH): Popular for small electronics, offering easy plug-and-play use.
- Molex Connectors: Found in medical or industrial-grade devices needing secure connections.
- Custom Wire Leads: Some applications require bare wires or custom headers.
When ordering from a supplier like Ufine Battery, connectors can be fully customized to match your device’s board or charging system.
6. Where is the circular LiPo battery used?
Round batteries are making waves in several innovative industries:
- Wearable Devices: Smartwatches, rings, health trackers, earbuds.
- Medical Equipment: Portable monitors, hearing aids, patches.
- Smart Accessories: Bluetooth remotes, digital pens, smart jewelry.
- IoT Sensors: Environmental monitors, beacons, RFID readers.
- Consumer Electronics: LED gadgets, small toys, AR/VR devices.
Because of their compact and lightweight design, LiPo circular batteries are essential in the growing world of miniaturized electronics.
7. Need a custom circular battery? Let Ufine help
Ufine Battery is not just a supplier—we’re your battery design partner. Whether you’re building a smart ring, a wireless sensor, or a custom wearable, we offer:
✅ Custom sizes, voltages, and shapes
✅ Low and high-temp battery options
✅ Fast prototyping and global shipping
✅ Full safety certifications (CE, RoHS, UN38.3, MSDS)
Reach out to Ufine Battery today and let us power your innovation with the perfect circular LiPo battery.
8. FAQs
Can I replace a round LiPo battery with a coin cell?
No, they are not interchangeable. Coin cells are typically non-rechargeable and lower in capacity. LiPo round batteries offer higher energy density and rechargeability.
Are circular LiPo batteries safe?
Yes—when manufactured with protection circuits and used properly. Always avoid puncturing, short-circuiting, or exposing them to high heat.
How long does a circular LiPo battery last?
Usually between 300–500 charge cycles, depending on usage. High-quality models like those from Ufine can last even longer.
Can these batteries be made waterproof?
Yes, many round LiPo batteries can be coated or encased for IP-rated waterproofing, ideal for wearable or outdoor applications.
How long does it take to charge a round LiPo battery?
It depends on the capacity and charger, but most small circular LiPo batteries can charge fully in 30 minutes to 2 hours.
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