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AUK Cylindrical Lithium Polymer Battery Round LiPo Cell 703533 3.7V 750mAh 2.775Wh With UN38.3 CE For Smart Sports Products

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AUK Cylindrical Lithium Polymer Battery Round LiPo Cell 703533 3.7V 750mAh 2.775Wh With UN38.3 CE For Smart Sports Products

MOQ:	1000PCS
Price:	Negotiable
Standard Packaging:	Carton box
Delivery Period:	5-8 Work Days
Payment Method:	L/C, D/A, D/P, T/T, Western Union, MoneyGram
Supply Capacity:	10000pcs/day

Detail Information

Product Description

Detail Information

Place of Origin

China

Brand Name

Certification

Model Number

703533

Battery Type:

Capacity:

750mAh

Certifications:

Charge Rate:

Connector Type:

Fully Charged Voltage:

Quality:

No Leakage & No Rusted

Minimum Order Quantity:

1000PCS

Price:

Negotiable

Packaging Details:

Carton box

Delivery Time:

5-8 Work Days

Payment Terms:

L/C, D/A, D/P, T/T, Western Union, MoneyGram

Supply Ability:

10000pcs/day

Product Description

AUK Cylindrical Lithium Polymer Battery Round LiPo Cell 703533 3.7V 750mAh 2.775Wh With UN38.3 CE For Smart Sports Products

Product Description

Item	Value
Brand Name	AUKPower
Battery Model	703533- 750mah
Battery Size	73535mm TWL
Weight	11g
Max. Constant Charge Current	1C
Max. Constant Discharge Current	1C
Chargeable	Yes
Sample	Acceptable
Certification	UN38.3/MSDS/RoHS
Cycle life	≥ 500 Times
Payment term	T/T,Western Union,Paypal
Shipping	UPS /DHL/ Fedex /TNT/ Sea shipping
Application	Handlamp,Cleansing device, electric water replenishing device, electric blackhead suction device, electric eye care device, electric neck care device, electric breast pump, pregnancy tester, baby monitor, children's toys,Smart watches, headlights,walkie-talkie,GPS tracker

AUK Cylindrical Lithium Polymer Battery Round LiPo Cell 703533 3.7V 750mAh 2.775Wh With UN38.3 CE For Smart Sports Products 0

Welcome contact with us customized Any size lipo battery, via jimmy@aukpower.com. Tel:+86 15220259126

The Round Cell Revolution: Why Cylindrical LiPo Batteries Are Redefining Compact Wearable Design

By Hunan Auk New Energy Co., Ltd. — 19+ Years of Custom LiPo Engineering

Open any premium wireless earbud. Crack open a sleek smart ring. Disassemble a modern fitness tracker. What do you notice about the internal cavity?

It's round.

Or curved. Or cylindrical. But almost never rectangular.

Yet for years, product designers have been doing something counterintuitive: stuffing square batteries into round holes.

The result? Wasted space. Reduced capacity. Compromised ergonomics. And products that are thicker, heavier, and shorter-lived than they need to be.

At Hunan Auk New Energy, we spent 19 years studying this mismatch. And we arrived at a simple conclusion: The battery should match the cavity, not the other way around.

This is why we developed our Cylindrical Polymer Lithium Battery line—starting with the AUK 703533 Round LiPo Cell.

The 703533 Decoder: Precision Engineered for Round Cavities

Let's decode what this model number actually means:

Code Digit Meaning Value

70 Diameter 7.0mm

35 Width (cylinder height) 35mm

33 Depth/Configuration code Standard round cell

At 7mm in diameter and 35mm in length, the 703533 is specifically engineered to fit into the cylindrical battery housings common in:

True Wireless Stereo (TWS) Earbuds — The 7mm diameter fits perfectly into stem-style or button-style earbud housings

Smart Bracelets & Fitness Trackers — Slim enough for wrist-worn devices

Smart Rings — Emerging category requiring curved/round form factors

Hearing Aids — Medical-grade devices with cylindrical battery compartments

Bluetooth Trackers (Tile-style devices) — Small, round housings

Stylus Pens — Active styluses for tablets

Portable Medical Sensors — Compact diagnostic wearables

And with 750mAh capacity / 3.7V nominal voltage / 2.775Wh total energy, it delivers enough power for full-day active use—while remaining well under the IATA 100Wh air travel limit.

The "Square Peg, Round Hole" Problem: Why Shape Matters

Here's a thought experiment.

Take a standard rectangular pouch cell—say, a 30mm × 30mm square. Place it inside a 30mm diameter circular housing.

How much space is wasted?

Housing Shape Battery Shape Space Utilization

Round Rectangular (inscribed) ~64% (corners wasted)

Round Round (matched) ~98% (minimal waste)

Curved housing Flat battery Requires mechanical shims, wasted volume

That's 36% of your internal volume doing absolutely nothing but holding empty air.

Now imagine that wasted space instead being filled with more battery capacity. Or additional sensors. Or a larger speaker driver. Or a thinner overall device.

This is the promise of cylindrical polymer lithium batteries.

By matching the battery shape to the housing shape, you eliminate dead volume. Your device becomes:

Smaller for the same capacity

Longer-lasting for the same size

More comfortable to wear (no sharp edges)

Application Deep Dive: Where Round Cells Excel

1. TWS Earbuds & Wireless Audio

The TWS market has exploded, but battery life remains the #1 consumer complaint. Most earbuds use small rectangular pouch cells (like 451015 or 501012) that fit diagonally into cylindrical stems—wasting significant volume.

The 703533 round cell, by contrast, slides perfectly into cylindrical stem housings. At 750mAh, a pair of these delivers enough capacity for:

Usage Scenario Runtime Estimate

Continuous music playback 8-10 hours

Talk time (ANC on) 6-8 hours

Standby with auto-shutoff 100+ hours

Design Advantage: The 7mm diameter matches standard earbud stem thickness, allowing for slimmer, more elegant industrial design.

2. Smart Rings & Circular Wearables

The smart ring market is projected to grow from hundreds of millions to billions of dollars by 2030. These devices face a unique constraint: they must wrap around a finger, creating a curved internal cavity that conventional rectangular batteries cannot fill efficiently.

Grepow's recent curved battery white paper highlights the challenge: traditional winding processes create mechanical stress and wasted "dead zones" inside curved batteries.

Our cylindrical polymer cells offer an alternative approach: small-diameter round cells (as narrow as 4-7mm) that can be arranged radially or placed along the ring's curved interior. The 703533's 7mm diameter is small enough to integrate into the thickest part of a smart ring (typically the top housing where the sensor array sits).

3. Smart Bracelets & Fitness Trackers

Fitness trackers like the Xiaomi Mi Band or Fitbit Inspire series use rectangular display modules but curved wrist housings. The space between the rectangular screen and the curved wrist strap is traditionally dead volume—unless you use a cylindrical battery that curves along the wrist.

By placing a 703533 (or smaller variant) along the wrist-facing curve, designers can:

Increase total capacity by 30-40% compared to flat-only designs

Distribute weight more evenly (no "heavy spot" on top of wrist)

Create thinner overall profiles

4. Hearing Aids & Medical Wearables

Hearing aids traditionally use button cell batteries (zinc-air or silver-oxide) that are single-use and require frequent replacement. The shift to rechargeable hearing aids has created demand for small cylindrical LiPo cells that fit into the same cylindrical battery compartments.

The 703533's 7mm diameter matches standard hearing aid battery sizes (size 10, 312, 13), while providing:

750mAh of rechargeable capacity (compared to ~100mAh for disposable button cells)

500+ charge cycles

USB recharging (no more fumbling with tiny disposable batteries)

Critical Certification: The 703533 comes with UN38.3 and CE certifications—essential for medical devices shipped globally.

5. Bluetooth Trackers (Tile/Apple AirTag Form Factors)

The Apple AirTag and similar devices use a coin cell battery (CR2032) that is single-use and non-rechargeable. Users must replace them every 6-12 months.

A custom cylindrical polymer battery can replace the CR2032 entirely, offering:

USB-C or wireless recharging

Higher total capacity over device lifetime (500+ cycles vs. 1 cycle)

Integration with device firmware for battery status reporting

The 703533's dimensions (7mm × 35mm) are slightly larger than a CR2032 (20mm diameter × 3.2mm height), but can be adapted into larger tracker designs or spread across multiple cells.

The Customization Advantage: Your Round Cell, Your Dimensions

The 703533 is our standard round cell. But we understand that every device has unique constraints.

At Hunan Auk New Energy, we can manufacture cylindrical polymer batteries in ANY diameter and length you need.

Custom Parameter Our Capability

Diameter From 4mm to 20mm

Length From 15mm to 80mm

Capacity From 50mAh to 3000mAh

Voltage 3.7V, 7.4V (2S), or 11.1V (3S)

Connector JST, Molex, Hirose, pigtail wires, or custom

Protection PCM with over-charge, over-discharge, over-current, short-circuit, temperature protection

Certification UN38.3, CE, RoHS, UL (upon request)

This is the difference between forcing your design around an off-the-shelf battery and having the battery built around your design.

Our engineering team works directly with your mechanical designers to ensure:

Exact dimensional fit (within ±0.2mm tolerance)

Optimal capacity for your power budget

Correct connector orientation and wire exit points

Complete certification documentation for global shipping

UN38.3 & CE: Your Passport to Global Markets

The 703533-2P is fully certified for international distribution:

Certification What It Covers Required For

UN38.3 Safe air transport of lithium batteries Shipping by air (FedEx, DHL, UPS) to any country

CE EU safety and health standards European market access (EU 27 countries)

RoHS Restriction of hazardous substances Global environmental compliance

MSDS Material Safety Data Sheet Customs clearance worldwide

As Grepow's whitepaper notes, "battery safety is paramount for devices worn 24/7" . Our rigorous testing protocol includes 100% in-house inspection before any battery leaves our factory.

The Technical Specifications (For Your Engineering Team)

For the engineers reading this (and we know you are), here are the numbers that matter:

Parameter Specification

Nominal Voltage 3.7V

Nominal Capacity 750mAh

Total Energy 2.775Wh

Charge Voltage 4.2V ±0.05V

Discharge Cut-off 2.75V

Standard Charge 0.5C (375mA)

Standard Discharge 0.2C (150mA)

Max Continuous Discharge 1C (750mA)

Cycle Life ≥500 cycles (80% of initial capacity)

Operating Temp (Charge) 0°C to 45°C

Operating Temp (Discharge) -10°C to 60°C

Dimensions 7.0mm (diameter) × 35mm (length)

Weight Approximately 16g

Certifications UN38.3, CE, RoHS

Why Hunan Auk New Energy?

With 19+ years in the lithium battery industry, we are not a trading company. We are a manufacturer with:

Capability What It Means For You

In-house engineering Our team supports your design from concept to production—no third-party delays

Grade A cells only No recycled, no B-grade, no exceptions

Flexible MOQ From 500 units for prototyping to mass production

Fast sample turnaround Custom samples in 2-3 weeks

Complete traceability Every battery batch is tested and documented

Global shipping UN38.3 certified for air freight to 90+ countries

Any shape, any size Cylindrical, rectangular, curved—we build what you need

As one of our competitors notes, "lithium battery is one kind of customized product" . We take that to heart. Your device is unique. Your battery should be too.

The Bottom Line: Stop Forcing Square Pegs into Round Holes

The AUK 703533 Cylindrical Polymer Lithium Battery represents a philosophy: the battery should serve the product, not the other way around.

At 7mm diameter and 35mm length, with 750mAh capacity and UN38.3/CE certifications, it is ready to power your TWS earbuds, smart rings, fitness trackers, hearing aids, and Bluetooth trackers.

And if 7mm × 35mm isn't exactly what you need? We'll build one that is.

Ready to Engineer a Better Fit?

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AUK Cylindrical Lithium Polymer Battery Round LiPo Cell 703533 3.7V 750mAh 2.775Wh With UN38.3 CE For Smart Sports Products

MOQ:	1000PCS
Price:	Negotiable
Standard Packaging:	Carton box
Delivery Period:	5-8 Work Days
Payment Method:	L/C, D/A, D/P, T/T, Western Union, MoneyGram
Supply Capacity:	10000pcs/day

Detail Information

Product Description

Detail Information

Place of Origin

China

Brand Name

AUK

Certification

MSDS

Model Number

703533

Battery Type:

Lipo

Capacity:

750mAh

Certifications:

MSDS

Charge Rate:

Connector Type:

JST

Fully Charged Voltage:

4.2V

Quality:

No Leakage & No Rusted

Minimum Order Quantity:

1000PCS

Price:

Negotiable

Packaging Details:

Carton box

Delivery Time:

5-8 Work Days

Payment Terms:

L/C, D/A, D/P, T/T, Western Union, MoneyGram

Supply Ability:

10000pcs/day

Product Description

AUK Cylindrical Lithium Polymer Battery Round LiPo Cell 703533 3.7V 750mAh 2.775Wh With UN38.3 CE For Smart Sports Products

Product Description

Item	Value
Brand Name	AUKPower
Battery Model	703533- 750mah
Battery Size	73535mm TWL
Weight	11g
Max. Constant Charge Current	1C
Max. Constant Discharge Current	1C
Chargeable	Yes
Sample	Acceptable
Certification	UN38.3/MSDS/RoHS
Cycle life	≥ 500 Times
Payment term	T/T,Western Union,Paypal
Shipping	UPS /DHL/ Fedex /TNT/ Sea shipping
Application	Handlamp,Cleansing device, electric water replenishing device, electric blackhead suction device, electric eye care device, electric neck care device, electric breast pump, pregnancy tester, baby monitor, children's toys,Smart watches, headlights,walkie-talkie,GPS tracker

AUK Cylindrical Lithium Polymer Battery Round LiPo Cell 703533 3.7V 750mAh 2.775Wh With UN38.3 CE For Smart Sports Products 0

Welcome contact with us customized Any size lipo battery, via jimmy@aukpower.com. Tel:+86 15220259126

The Round Cell Revolution: Why Cylindrical LiPo Batteries Are Redefining Compact Wearable Design

By Hunan Auk New Energy Co., Ltd. — 19+ Years of Custom LiPo Engineering

Open any premium wireless earbud. Crack open a sleek smart ring. Disassemble a modern fitness tracker. What do you notice about the internal cavity?

It's round.

Or curved. Or cylindrical. But almost never rectangular.

Yet for years, product designers have been doing something counterintuitive: stuffing square batteries into round holes.

The result? Wasted space. Reduced capacity. Compromised ergonomics. And products that are thicker, heavier, and shorter-lived than they need to be.

At Hunan Auk New Energy, we spent 19 years studying this mismatch. And we arrived at a simple conclusion: The battery should match the cavity, not the other way around.

This is why we developed our Cylindrical Polymer Lithium Battery line—starting with the AUK 703533 Round LiPo Cell.

The 703533 Decoder: Precision Engineered for Round Cavities

Let's decode what this model number actually means:

Code Digit Meaning Value

70 Diameter 7.0mm

35 Width (cylinder height) 35mm

33 Depth/Configuration code Standard round cell

At 7mm in diameter and 35mm in length, the 703533 is specifically engineered to fit into the cylindrical battery housings common in:

True Wireless Stereo (TWS) Earbuds — The 7mm diameter fits perfectly into stem-style or button-style earbud housings

Smart Bracelets & Fitness Trackers — Slim enough for wrist-worn devices

Smart Rings — Emerging category requiring curved/round form factors

Hearing Aids — Medical-grade devices with cylindrical battery compartments

Bluetooth Trackers (Tile-style devices) — Small, round housings

Stylus Pens — Active styluses for tablets

Portable Medical Sensors — Compact diagnostic wearables

And with 750mAh capacity / 3.7V nominal voltage / 2.775Wh total energy, it delivers enough power for full-day active use—while remaining well under the IATA 100Wh air travel limit.

The "Square Peg, Round Hole" Problem: Why Shape Matters

Here's a thought experiment.

Take a standard rectangular pouch cell—say, a 30mm × 30mm square. Place it inside a 30mm diameter circular housing.

How much space is wasted?

Housing Shape Battery Shape Space Utilization

Round Rectangular (inscribed) ~64% (corners wasted)

Round Round (matched) ~98% (minimal waste)

Curved housing Flat battery Requires mechanical shims, wasted volume

That's 36% of your internal volume doing absolutely nothing but holding empty air.

Now imagine that wasted space instead being filled with more battery capacity. Or additional sensors. Or a larger speaker driver. Or a thinner overall device.

This is the promise of cylindrical polymer lithium batteries.

By matching the battery shape to the housing shape, you eliminate dead volume. Your device becomes:

Smaller for the same capacity

Longer-lasting for the same size

More comfortable to wear (no sharp edges)

Application Deep Dive: Where Round Cells Excel

1. TWS Earbuds & Wireless Audio

The 703533 round cell, by contrast, slides perfectly into cylindrical stem housings. At 750mAh, a pair of these delivers enough capacity for:

Usage Scenario Runtime Estimate

Continuous music playback 8-10 hours

Talk time (ANC on) 6-8 hours

Standby with auto-shutoff 100+ hours

Design Advantage: The 7mm diameter matches standard earbud stem thickness, allowing for slimmer, more elegant industrial design.

2. Smart Rings & Circular Wearables

Grepow's recent curved battery white paper highlights the challenge: traditional winding processes create mechanical stress and wasted "dead zones" inside curved batteries.

3. Smart Bracelets & Fitness Trackers

By placing a 703533 (or smaller variant) along the wrist-facing curve, designers can:

Increase total capacity by 30-40% compared to flat-only designs

Distribute weight more evenly (no "heavy spot" on top of wrist)

Create thinner overall profiles

4. Hearing Aids & Medical Wearables

The 703533's 7mm diameter matches standard hearing aid battery sizes (size 10, 312, 13), while providing:

750mAh of rechargeable capacity (compared to ~100mAh for disposable button cells)

500+ charge cycles

USB recharging (no more fumbling with tiny disposable batteries)

Critical Certification: The 703533 comes with UN38.3 and CE certifications—essential for medical devices shipped globally.

5. Bluetooth Trackers (Tile/Apple AirTag Form Factors)

The Apple AirTag and similar devices use a coin cell battery (CR2032) that is single-use and non-rechargeable. Users must replace them every 6-12 months.

A custom cylindrical polymer battery can replace the CR2032 entirely, offering:

USB-C or wireless recharging

Higher total capacity over device lifetime (500+ cycles vs. 1 cycle)

Integration with device firmware for battery status reporting

The 703533's dimensions (7mm × 35mm) are slightly larger than a CR2032 (20mm diameter × 3.2mm height), but can be adapted into larger tracker designs or spread across multiple cells.

The Customization Advantage: Your Round Cell, Your Dimensions

The 703533 is our standard round cell. But we understand that every device has unique constraints.

At Hunan Auk New Energy, we can manufacture cylindrical polymer batteries in ANY diameter and length you need.

Custom Parameter Our Capability

Diameter From 4mm to 20mm

Length From 15mm to 80mm

Capacity From 50mAh to 3000mAh

Voltage 3.7V, 7.4V (2S), or 11.1V (3S)

Connector JST, Molex, Hirose, pigtail wires, or custom

Protection PCM with over-charge, over-discharge, over-current, short-circuit, temperature protection

Certification UN38.3, CE, RoHS, UL (upon request)

This is the difference between forcing your design around an off-the-shelf battery and having the battery built around your design.

Our engineering team works directly with your mechanical designers to ensure:

Exact dimensional fit (within ±0.2mm tolerance)

Optimal capacity for your power budget

Correct connector orientation and wire exit points

Complete certification documentation for global shipping

UN38.3 & CE: Your Passport to Global Markets

The 703533-2P is fully certified for international distribution:

Certification What It Covers Required For

UN38.3 Safe air transport of lithium batteries Shipping by air (FedEx, DHL, UPS) to any country

CE EU safety and health standards European market access (EU 27 countries)

RoHS Restriction of hazardous substances Global environmental compliance

MSDS Material Safety Data Sheet Customs clearance worldwide

As Grepow's whitepaper notes, "battery safety is paramount for devices worn 24/7" . Our rigorous testing protocol includes 100% in-house inspection before any battery leaves our factory.

The Technical Specifications (For Your Engineering Team)

For the engineers reading this (and we know you are), here are the numbers that matter:

Parameter Specification

Nominal Voltage 3.7V

Nominal Capacity 750mAh

Total Energy 2.775Wh

Charge Voltage 4.2V ±0.05V

Discharge Cut-off 2.75V

Standard Charge 0.5C (375mA)

Standard Discharge 0.2C (150mA)

Max Continuous Discharge 1C (750mA)

Cycle Life ≥500 cycles (80% of initial capacity)

Operating Temp (Charge) 0°C to 45°C

Operating Temp (Discharge) -10°C to 60°C

Dimensions 7.0mm (diameter) × 35mm (length)

Weight Approximately 16g

Certifications UN38.3, CE, RoHS

Why Hunan Auk New Energy?

With 19+ years in the lithium battery industry, we are not a trading company. We are a manufacturer with:

Capability What It Means For You

In-house engineering Our team supports your design from concept to production—no third-party delays

Grade A cells only No recycled, no B-grade, no exceptions

Flexible MOQ From 500 units for prototyping to mass production

Fast sample turnaround Custom samples in 2-3 weeks

Complete traceability Every battery batch is tested and documented

Global shipping UN38.3 certified for air freight to 90+ countries

Any shape, any size Cylindrical, rectangular, curved—we build what you need

As one of our competitors notes, "lithium battery is one kind of customized product" . We take that to heart. Your device is unique. Your battery should be too.

The Bottom Line: Stop Forcing Square Pegs into Round Holes

The AUK 703533 Cylindrical Polymer Lithium Battery represents a philosophy: the battery should serve the product, not the other way around.

At 7mm diameter and 35mm length, with 750mAh capacity and UN38.3/CE certifications, it is ready to power your TWS earbuds, smart rings, fitness trackers, hearing aids, and Bluetooth trackers.

And if 7mm × 35mm isn't exactly what you need? We'll build one that is.

Ready to Engineer a Better Fit?

Tags: