Why Battery Swelling Happens in Wearable Devices?
I often meet teams after swelling complaints appear. The product looks finished, the launch is…
The 401520 3.7V 100mAh Li-polymer Battery is designed for small electronic devices that require lightweight structure, stable voltage output, and flexible battery integration. With a 3.7V nominal voltage and 100mAh capacity, this battery is suitable for Bluetooth devices, wearable sensors, smart pens, electronic tags, compact medical devices, smart accessories, and other miniature rechargeable electronics.
As a professional lithium polymer battery manufacturer, LithoTop provides customized 401520 Li-polymer battery solutions, including connector selection, wire length, PCM protection, NTC, cable direction, battery labels, shrink wrap, packaging, and OEM/ODM battery pack assembly.
| Product Type | Li-Polymer battery |
|---|---|
| Model number | 401520 |
| Voltage (Nominal) | 3.7V |
| Capacity (Nominal) | 100mAh |
| Dimensions | 4.0±0.2*15±0.5*20±2.5mm |
| Constant Discharge Current | Typically 0.5C-1C |
| Working Temperature | charge: 0-45℃; discharge: -20-60℃ |
| Certification | ROHS |
Delivering superior performance consistency and longer cycle life through automated cell matching technology designed for heavy-duty industrial applications.

The 401520 3.7V 100mAh Li-polymer battery is designed for compact devices where internal space, battery weight, and stable rechargeable performance are important. Its small pouch cell structure makes it suitable for slim housings, wearable modules, wireless accessories, smart tags, and low-power portable electronics.
With 100mAh capacity, this battery can support low-power circuits such as Bluetooth modules, sensors, LED indicators, small control boards, memory chips, and standby systems. It is a practical choice for product developers who need a compact rechargeable battery with reliable output and flexible customization.
LithoTop applies strict production control during cell selection, capacity testing, voltage inspection, internal resistance testing, PCM assembly, aging verification, appearance inspection, and final quality control. These processes help ensure stable battery performance, reliable safety protection, and consistent mass production quality.


| Models | Voltage(V) | Capacity(mAh) | Cell Dimensions(mm) | Shape |
|---|---|---|---|---|
| 400810 | 3.7 | 15 | 4.0*8*10mm | Rectangle |
| 400824 | 3.7 | 55 | 4.0*8*24mm | Rectangle |
| 400828 | 3.7 | 62 | 4.0*8*28mm | Rectangle |
| 400830 | 3.7 | 80 | 4.0*8*30mm | Rectangle |
| 400835 | 3.7 | 100 | 4.0*8*35mm | Rectangle |
| 400912 | 3.7 | 30 | 4.0*9*12mm | Rectangle |
| 400920 | 3.7 | 60 | 4.0*9*20mm | Rectangle |
| 400930 | 3.7 | 90 | 4.0*9*30mm | Rectangle |
| 400940 | 3.7 | 120 | 4.0*9*40mm | Rectangle |
| 401010 | 3.7 | 25 | 4.0*10*10mm | Rectangle |
| 401012 | 3.7 | 30 | 4.0*10*12mm | Rectangle |
| 401014 | 3.7 | 35 | 4.0*10*14mm | Rectangle |
| 401015 | 3.7 | 40 | 4.0*10*15mm | Rectangle |
| 401018 | 3.7 | 40-10C | 4.0*10*18mm | Rectangle |
| 401020 | 3.7 | 55 | 4.0*10*20mm | Rectangle |
| 401020 | 3.7 | 50-5C | 4.0*10*20mm | Rectangle |
| 401025 | 3.7 | 75 | 4.0*10*25mm | Rectangle |
| 401027 | 3.7 | 80 | 4.0*10*27mm | Rectangle |
| 401030 | 3.7 | 90 | 4.0*10*30mm | Rectangle |
| 401035 | 3.7 | 110 | 4.0*10*35mm | Rectangle |
| 401050 | 3.7 | 160 | 4.0*10*50mm | Rectangle |
| 401114 | 3.7 | 35 | 4.0*11*14mm | Rectangle |
| 401129 | 3.7 | 110 | 4.0*11*29mm | Rectangle |
| 401214 | 3.7 | 45 | 4.0*12*14mm | Rectangle |
| 401220 | 3.7 | 70 | 4.0*12*20mm | Rectangle |
| 401225 | 3.7 | 100 | 4.0*12*25mm | Rectangle |
| 401228 | 3.7 | 110 | 4.0*12*28mm | Rectangle |
| 401230 | 3.7 | 120 | 4.0*12*30mm | Rectangle |
| 401235 | 3.7 | 130 | 4.0*12*35mm | Rectangle |
| 401342 | 3.7 | 200 | 4.0*13*42mm | Rectangle |
| 401415 | 3.7 | 50 | 4.0*14*15mm | Rectangle |
| 401423 | 3.7 | 100 | 4.0*14*23mm | Rectangle |
| 401425 | 3.7 | 120 | 4.0*14*25mm | Rectangle |
| 401430 | 3.8 | 180 | 4.0*14*30mm | Rectangle |
| 401434 | 3.7 | 160 | 4.0*14*34mm | Rectangle |
| 401438 | 3.7 | 200 | 4.0*14*38mm | Rectangle |
| 401515 | 3.7 | 65 | 4.0*15*15mm | Rectangle |
| 401520 | 3.7 | 100 | 4.0*15*20mm | Rectangle |
| 401522 | 3.7 | 110 | 4.0*15*22mm | Rectangle |
| 401523 | 3.7 | 120 | 4.0*15*23mm | Rectangle |
| 401525 | 3.7 | 120 | 4.0*15*25mm | Rectangle |
| 401535 | 3.7 | 200 | 4.0*15*35mm | Rectangle |
| 401726 | 3.7 | 170 | 4.0*17*26mm | Rectangle |
| 401730 | 3.7 | 180 | 4.0*17*30mm | Rectangle |
| 401835 | 3.7 | 270 | 4.0*18*35mm | Rectangle |
| 402020 | 3.7 | 120 | 4.0*20*20mm | Rectangle |
| 402025 | 3.7 | 150 | 4.0*20*25mm | Rectangle |
| 402026 | 3.7 | 190 | 4.0*20*26mm | Rectangle |
| 402030 | 3.7 | 200 | 4.0*20*30mm | Rectangle |
| 402030 | 3.8 | 280 | 4.0*20*30mm | Rectangle |
| 402035 | 3.7 | 250 | 4.0*20*35mm | Rectangle |
| 402040 | 3.7 | 320 | 4.0*20*40mm | Rectangle |
| 402050 | 3.7 | 400 | 4.0*20*50mm | Rectangle |
| 402120 | 3.7 | 160 | 4.0*21*20mm | Rectangle |
| 402247 | 3.7 | 450 | 4.0*22*47mm | Rectangle |
| 402323 | 3.7 | 150 | 4.0*23*23mm | Rectangle |
| 402424 | 3.7 | 220 | 4.0*24*24mm | Rectangle |
| 402424 | 3.8 | 260 | 4.0*24*24mm | Rectangle |
| 402426 | 3.7 | 250 | 4.0*24*26mm | Rectangle |
| 402525 | 3.7 | 250 | 4.0*25*25mm | Rectangle |
| 402530 | 3.7 | 300 | 4.0*25*30mm | Rectangle |
| 402535 | 3.7 | 320 | 4.0*25*35mm | Rectangle |
| 402540 | 3.7 | 400 | 4.0*25*40mm | Rectangle |
| 402550 | 3.7 | 500 | 4.0*25*50mm | Rectangle |
| 4025100 | 3.7 | 1000 | 4.0*25*100mm | Rectangle |
| 4025130 | 3.7 | 1500 | 4.0*25*130mm | Rectangle |
| 402626 | 3.8 | 320 | 4.0*26*26mm | Rectangle |
| 402780 | 3.7 | 1000 | 4.0*27*80mm | Rectangle |
| 403030 | 3.7 | 300 | 4.0*30*30mm | Rectangle |
| 403035 | 3.7 | 300-15C | 4.0*30*35mm | Rectangle |
| 403035 | 3.7 | 400 | 4.0*30*35mm | Rectangle |
| 403040 | 3.7 | 500 | 4.0*30*40mm | Rectangle |
| 403048 | 3.7 | 600 | 4.0*30*48mm | Rectangle |
| 403450 | 3.7 | 800 | 4.0*34*50mm | Rectangle |
| 404050 | 3.7 | 850 | 4.0*40*50mm | Rectangle |
| 404060 | 3.7 | 1200 | 4.0*40*60mm | Rectangle |
| 404355 | 3.7 | 900 | 4.0*43*55mm | Rectangle |
| 411515 | 3.8 | 75 | 4.1*15*15mm | Rectangle |
| 411530 | 3.7 | 150 | 4.1*15*30mm | Rectangle |
| 412226 | 3.8 | 260 | 4.1*22*26mm | Rectangle |
| 420811 | 3.7 | 25 | 4.2*8*11mm | Rectangle |
| 420840 | 3.7 | 110 | 4.2*8*40mm | Rectangle |
| 421233 | 3.7 | 125 | 4.2*12*33mm | Rectangle |
| 421327 | 3.9 | 190 | 4.2*13*27mm | Rectangle |
| 421427 | 3.7 | 140 | 4.2*14*27mm | Rectangle |
| 421530 | 3.7 | 150 | 4.2*15*30mm | Rectangle |
| 421535 | 3.7 | 200 | 4.2*15*35mm | Rectangle |
| 421832 | 3.7 | 220 | 4.2*18*32mm | Rectangle |
| 421920 | 3.7 | 120 | 4.2*19*20mm | Rectangle |
| 422025 | 3.7 | 180 | 4.2*20*25mm | Rectangle |
| 422028 | 3.7 | 235 | 4.2*20*28mm | Rectangle |
| 422123 | 3.7 | 200 | 4.2*21*23mm | Rectangle |
| 422424 | 3.8 | 260 | 4.2*24*24mm | Rectangle |
| 422530 | 3.7 | 300 | 4.2*25*30mm | Rectangle |
| 423034 | 3.7 | 400 | 4.2*30*34mm | Rectangle |
| 423048 | 3.7 | 520 | 4.2*30*48mm | Rectangle |
| 423060 | 3.7 | 800 | 4.2*30*60mm | Rectangle |
| 423282 | 3.8 | 1450 | 4.2*32*82mm | Rectangle |
| 423450 | 3.7 | 800 | 4.2*34*50mm | Rectangle |
| 431215 | 3.7 | 45 | 4.3*12*15mm | Rectangle |
| 431219 | 3.7 | 80 | 4.3*12*19mm | Rectangle |
| 431730 | 3.7 | 200 | 4.3*17*30mm | Rectangle |
| 432023 | 3.7 | 150 | 4.3*20*23mm | Rectangle |
| 432525 | 3.7 | 320 | 4.3*25*25mm | Rectangle |
| 433950 | 3.7 | 1000 | 4.3*39*50mm | Rectangle |
| 434278 | 3.7 | 1500 | 4.3*42*78mm | Rectangle |
| 450820 | 3.7 | 50 | 4.5*8*20mm | Rectangle |
| 450838 | 3.7 | 115 | 4.5*8*38mm | Rectangle |
| 450840 | 3.7 | 120 | 4.5*8*40mm | Rectangle |
| 450843 | 3.7 | 125 | 4.5*8*43mm | Rectangle |
| 450912 | 3.7 | 40 | 4.5*9*12mm | Rectangle |
| 451012 | 3.7 | 40 | 4.5*10*12mm | Rectangle |
| 451014 | 3.7 | 50 | 4.5*10*14mm | Rectangle |
| 451033 | 3.7 | 135 | 4.5*10*33mm | Rectangle |
| 451116 | 3.7 | 68 | 4.5*11*16mm | Rectangle |
| 451214 | 3.7 | 50 | 4.5*12*14mm | Rectangle |
| 451219 | 3.7 | 80 | 4.5*12*19mm | Rectangle |
| 451225 | 3.7 | 100 | 4.5*12*25mm | Rectangle |
| 451360 | 3.7 | 350 | 4.5*13*60mm | Rectangle |
| 451417 | 3.7 | 75 | 4.5*14*17mm | Rectangle |
| 451535 | 3.7 | 200 | 4.5*15*35mm | Rectangle |
| 451616 | 3.7 | 95 | 4.5*16*16mm | Rectangle |
| 451668 | 3.7 | 550 | 4.5*16*68mm | Rectangle |
| 451730 | 3.7 | 200 | 4.5*17*30mm | Rectangle |
| 451819 | 3.7 | 110 | 4.5*18*19mm | Rectangle |
| 451820 | 3.7 | 140 | 4.5*18*20mm | Rectangle |
| 451825 | 3.7 | 200 | 4.5*18*25mm | Rectangle |
| 451835 | 3.7 | 280 | 4.5*18*35mm | Rectangle |
| 451860 | 3.7 | 500 | 4.5*18*60mm | Rectangle |
| 451917 | 3.8 | 145 | 4.5*19*17mm | Rectangle |
| 451940 | 3.8 | 400 | 4.5*19*40mm | Rectangle |
| 452025 | 3.7 | 150 | 4.5*20*25mm | Rectangle |
| 452030 | 3.7 | 250 | 4.5*20*30mm | Rectangle |
| 452035 | 3.7 | 300 | 4.5*20*35mm | Rectangle |
| 452067 | 3.7 | 700 | 4.5*20*67mm | Rectangle |
| 452526 | 3.7 | 300 | 4.5*25*26mm | Rectangle |
| 452530 | 3.7 | 340 | 4.5*25*30mm | Rectangle |
| 452547 | 3.7 | 550 | 4.5*25*47mm | Rectangle |
| 452550 | 3.7 | 500 | 4.5*25*50mm | Rectangle |
| 452631 | 3.7 | 340 | 4.5*26*31mm | Rectangle |
| 452728 | 3.8 | 400 | 4.5*27*28mm | Rectangle |
| 453038 | 3.7 | 500 | 4.5*30*38mm | Rectangle |
| 453040 | 3.7 | 500 | 4.5*30*40mm | Rectangle |
| 453048 | 3.7 | 650 | 4.5*30*48mm | Rectangle |
| 453450 | 3.7 | 1000 | 4.5*34*50mm | Rectangle |
| 453535 | 3.7 | 350 | 4.5*35*35mm | Rectangle |
| 471215 | 3.5 | 55 | 4.7*12*15mm | Rectangle |
| 473048 | 3.7 | 800 | 4.7*30*48mm | Rectangle |
| 481014 | 3.7 | 45 | 4.8*10*14mm | Rectangle |
| 481015 | 3.7 | 50 | 4.8*10*15mm | Rectangle |
| 481220 | 3.7 | 80 | 4.8*12*20mm | Rectangle |
| 481445 | 3.7 | 250 | 4.8*14*45mm | Rectangle |
| 481530 | 3.7 | 180 | 4.8*15*30mm | Rectangle |
| 481724 | 3.7 | 170 | 4.8*17*24mm | Rectangle |
| 481726 | 3.7 | 200 | 4.8*17*26mm | Rectangle |
| 481730 | 3.7 | 230 | 4.8*17*30mm | Rectangle |
| 481923 | 3.7 | 190 | 4.8*19*23mm | Rectangle |
| 482530 | 3.7 | 300 | 4.8*25*30mm | Rectangle |
| 483070 | 3.7 | 1000 | 4.8*30*70mm | Rectangle |
| 484078 | 3.7 | 2050 | 4.8*40*78mm | Rectangle |
| 492728 | 3.7 | 350 | 4.9*27*28mm | Rectangle |
*Contact us for custom LiPo battery or customize your special battery !
Discover how we helps global customers solve real-world battery challenges through customized lithium battery solutions.
A Spanish education technology company was developing a rechargeable smart stylus for digital learning tablets. The product needed to power a small control board, pressure detection circuit, Bluetooth pairing function, LED indicator, and standby system. The customer’s early prototype used a larger battery, but it made the stylus body too thick and affected the writing experience.
The customer contacted LithoTop because they needed a compact 3.7V rechargeable Li-polymer battery with stable output, small size, customized wire assembly, and RoHS support for European sales. LithoTop reviewed the stylus diameter, internal PCB layout, standby current, Bluetooth activation cycle, charging method, LED load, and target usage time.
After evaluation, LithoTop recommended the 401520 3.7V 100mAh Li-polymer Battery. Our engineering team judged that the 100mAh capacity was suitable for the stylus operating profile, while the compact pouch cell structure helped keep the product slim and comfortable to hold.
During sample development, LithoTop customized the wire length, connector type, cable outlet direction, PCM protection, insulation layer, and label format according to the customer’s assembly process. Sample batteries were tested through writing simulation, Bluetooth pairing cycles, LED indication testing, standby evaluation, charging compatibility checking, and installation fit validation.
Because the product was planned for European distribution, LithoTop also supported RoHS documentation preparation for the battery project. Before mass production, both teams confirmed golden samples, battery dimensions, connector durability, label details, packaging requirements, RoHS support documents, and incoming inspection standards.
The final battery solution helped the customer keep the smart stylus slim while achieving stable rechargeable performance. For the customer, this improved writing comfort, reduced mechanical redesign pressure, and supported smoother RoHS preparation for European market entry.
A Canadian sports safety company was developing a compact wireless sensor module for ski helmets. The device needed to record motion data, detect impact events, activate an LED status indicator, and send short wireless updates to a mobile application. The battery had to fit into a narrow sensor enclosure without adding noticeable weight to the helmet.
The customer approached LithoTop after testing several small rechargeable batteries that were either too large for the enclosure or unstable during short wireless transmission events. They needed a miniature lithium polymer battery that could balance compact size, reliable output, and repeatable production quality.
LithoTop analyzed the sensor’s standby current, motion sampling cycle, wireless transmission peak, LED indication time, charging circuit, enclosure structure, cable outlet position, and expected usage pattern during winter sports activities. Based on this evaluation, LithoTop recommended the 401520 3.7V 100mAh Li-polymer battery as a compact rechargeable power source.
During prototype development, LithoTop optimized the PCM protection design, wire routing, connector position, insulation layer, and outer packaging method to improve assembly reliability. Sample batteries were tested through motion recording simulation, wireless pulse discharge testing, LED status testing, voltage stability checking, charge-discharge cycling, storage testing, and installation fit evaluation inside the helmet sensor housing.
Before pilot production, the customer confirmed approved sample performance, cable durability, battery dimensions, connector reliability, packaging method, and batch inspection requirements. LithoTop then controlled production according to the confirmed golden sample and quality standards.
The final battery solution helped the helmet sensor maintain stable operation while keeping the device compact and lightweight. For the customer, this improved product comfort, reduced battery-related shutdown risk, and supported stronger field testing with winter sports users.
A reliable 401520 Li-polymer battery requires more than a small cell size. Battery performance depends on capacity consistency, voltage stability, internal resistance control, PCM protection design, cable outlet direction, connector reliability, insulation method, and final aging inspection.
LithoTop supports customers from sample evaluation to mass production with professional engineering support, flexible customization, strict production inspection, and project-based compliance documentation support. Our team can help evaluate battery size, runtime target, charging method, operating current, protection circuit, connector type, NTC requirement, and real application conditions before confirming the final battery solution.
Powering leading batteries across wearables, medical devices, IoT, and consumer electronics in 30+ countries..


Find answers to the most common questions about ordering, shipping, certifications, and working with lithotop as your battery partner.
Engineer’s will make inner BOM according to your confirmed samples. And our quality control teams continuously monitor the entire manufacturing process to ensure the each mass production is the same as samples.
LithoTop specializes in custom lithium battery solutions, including LiPo batteries, Li-ion battery packs, LiFePO4 batteries, high-rate drone batteries, curved batteries, ultra-thin batteries, and custom rechargeable battery packs for industrial and consumer applications.
LithoTop focuses on:Custom battery solutions for special applications, own developed PCB/PCM to help you with Competitive factory-direct pricing, Experience with difficult battery projects such as curved, ultra-thin, and high-discharge batteries. Long-term cooperation support for startups and established brands.
Yes. LithoTop provides fully customized battery solutions based on your device requirements, including voltage, capacity, discharge rate, dimensions, connector type, PCM/BMS protection, and special shapes such as curved or ultra-thin batteries.
Standard samples are usually available quickly about 3-7 days, while custom battery projects typically require evaluation, engineering confirmation, prototyping, and testing. The timeline depends on battery specifications, and certification requirements. Mass order is about 30 working days.
Depending on the product and project requirements, LithoTop batteries can support certifications including UN38.3, MSDS, CE, RoHS, IEC62133, UL , and other transportation or safety compliance documents.
MOQ depends on the battery model and customization level. Standard batteries may support lower quantities like 100pcs, while fully customized battery projects usually require a development MOQ. LithoTop supports both prototype projects and mass production orders.
LithoTop follows strict quality control procedures including:Incoming material inspection, Cell matching and grading Capacity, and voltage testing, Aging and performance tests, 100% Safety inspections before shipment.Quality consistency is critical for battery reliability and long-term cooperation.
Normally, we ship our batteries via DHL, UPS, FedEx, air freight, or sea , depending on order size, destination, and customer preference.
Yes. LithoTop can support project-based certification and documentation requirements such as KC, CE, RoHS, UN38.3, MSDS, and other battery-related documents according to customer market requirements.
Explore more customized lithium battery solutions from LithoTop








LithoTop operates advanced lithium battery manufacturing facilities equipped with automated production lines, precision testing equipment, and strict quality control systems. From cell selection to battery assembly and final inspection, every process is carefully managed to ensure stable performance, reliable quality, and high production efficiency. With experienced engineers and strong OEM/ODM capability, we provide customized battery solutions for customers worldwide.
LithoTop provides comprehensive certification support for custom lithium batteries to help customers accelerate product development and global market entry. From prototype verification to mass production, our engineering team assists with battery compliance, transportation documentation, and international safety standards, reducing certification risks and shortening your project timeline.
Stay updated with the latest lithium battery industry news, product innovations, technology insights, and application trends from LithoTop. Explore expert articles, battery guides, and industry updates to learn more about custom lithium battery solutions, energy storage, UAV batteries, wearable device batteries, and advanced power technologies.
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