Industry Background: From Hearing Aids to Smart Bone-Conduction Devices

Bone-conduction hearing devices have grown rapidly with the advancement of hearing-assistive and wearable audio technology.
Unlike traditional air-conduction hearing aids, these devices transmit sound vibrations directly through the skull, bypassing
the ear canal and eardrum. :contentReference[oaicite:0]{index=0}

With Bluetooth LE Audio, AI noise reduction, enhanced vibration drivers, and
low-latency DSP processing, modern bone-conduction devices are evolving into high-performance smart wearables.
This evolution significantly increases energy demands and sets higher requirements for the internal battery system.

As a result, LiPo lithium polymer batteries and micro cylindrical lithium cells have become
critical components of next-generation open-ear audio products. They must deliver:

• All-day runtime in a very compact form factor
• Stable voltage for audio and AI algorithms
• High safety for long-hour skin contact
• Custom shapes that match ergonomic designs

For brands targeting sports, medical, or consumer audio markets, working with a professional

custom lithium polymer battery
partner is key to turning industrial design concepts into mass-producible products.

Key Power Challenges in Bone-Conduction Hearing Devices

Engineers and procurement teams face several battery-related challenges when designing bone-conduction hearing devices: :contentReference[oaicite:1]{index=1}

1. High Power Consumption from Vibration Transducers
   Bone-conduction drivers require continuous high-power output to generate sufficient vibration amplitude. This demands
   batteries with strong discharge capability, consistent power delivery, and the ability to support full-day runtime
   without noticeable performance drop.
2. Compact Device Structure & Flexible Battery Sizes
   Headbands, ear hooks, and glasses-style frames all offer very limited internal space. Batteries must be ultra-thin, lightweight,
   mechanically robust, and available in a wide range of custom sizes to match different industrial designs.
3. High Safety for Long-Hour Skin Contact
   As these devices are worn for hours at a time, often in direct contact with skin, the battery must provide excellent thermal
   stability, multi-layer protection (over-charge, over-discharge, short-circuit), and compliance with standards such as
   UN38.3 and IEC 62133.
4. Dependence on Stable Voltage Output
   Voltage instability may cause Bluetooth dropouts, AI algorithm failure, processing delays, or unstable vibration amplitude,
   directly impacting user experience.
5. Convenient & Safe Charging Requirements
   Users now expect USB-C, magnetic charging, or charging cases/bases. Batteries must integrate safely with these systems and
   support frequent partial charging.

Why LiPo & Cylindrical Lithium Batteries Are Ideal

To solve these challenges, modern bone-conduction hearing devices typically use a combination of LiPo lithium polymer
batteries and micro cylindrical lithium cells. :contentReference[oaicite:2]{index=2}

• LiPo Lithium Polymer Batteries
  Ultra-thin, lightweight, and highly customizable in length, width, and shape. Perfect for curved or ergonomic product
  structures such as headbands and open-ear glasses.
• Micro Cylindrical Lithium Cells
  Strong metal housing for mechanical durability, higher discharge capability, and higher volumetric energy density in
  certain layouts.
• Stable Voltage Curve
  Both LiPo and cylindrical lithium chemistries provide relatively flat discharge curves, which ensures stable DSP operation,
  Bluetooth connection, and consistent vibration output.
• Multi-Layer Safety Design
  When paired with appropriate PCM/BMS, these batteries provide over-charge, over-discharge, over-current, short-circuit,
  and temperature protection suitable for long-hour skin-contact wearables.
• Rechargeable & Environmentally Friendly
  Compared with primary cells, rechargeable lithium packs reduce waste and support sustainable, long-term device usage.

For extremely slim or curved structures, PKNERGY also offers

ultra-thin battery solutions for wearables
, which are specifically optimized for open-ear audio and health-monitoring devices.

Technical Insights: LiPo, Micro Cylindrical Cells & PCM/BMS Design

1. LiPo Lithium Polymer Batteries

• Typical thickness: 3–6 mm
• Nominal voltage: 3.7 V
• Discharge rate: 0.5C–3C
• Cycle life: 300–800 cycles depending on usage and C-rate
• Supports curved or irregular custom shapes for ergonomic devices

2. Micro Cylindrical Lithium Cells (e.g., 10180, 10220, 10440)

• Metal housing provides strong mechanical durability
• High discharge capability to drive powerful vibration transducers
• Higher energy density compared to LiPo of the same footprint
• Suitable for modules where extra robustness is required

3. PCM/BMS Integration for Safety & Smart Charging

A complete bone-conduction hearing device battery module usually integrates:

• Over-current protection
• Over-voltage and under-voltage protection
• Short-circuit protection
• NTC temperature detection
• Compatibility with USB-C, magnetic charging, or charging bases

For devices that fall into medical or quasi-medical categories, PKNERGY’s battery designs can be aligned with

Medical Device Power Solutions
, considering more stringent safety, verification, and documentation requirements.

Typical Application Scenarios

LiPo and micro cylindrical lithium battery packs for bone-conduction devices are widely used in: :contentReference[oaicite:3]{index=3}

• Hearing Assistance for Conductive Hearing Loss
• Sports & Outdoor Audio (running, cycling, hiking with open-ear listening)
• Children’s Auditory Rehabilitation
• Professional Communication Environments (industrial, security, and mission-critical teams)
• Entertainment & Daily Commuting

Many bone-conduction hearing devices are essentially a cross-over between medical assistance and

consumer electronics power solutions
, requiring both comfort and long-term reliability.

PKNERGY Custom Battery Solutions for Bone-Conduction Devices

As a custom battery manufacturer, PKNERGY supports companies developing bone-conduction hearing devices and smart open-ear
audio products with:

• Custom LiPo Battery Packs
  Tailor-made thickness, length, width, and tabs to fit headbands, glasses frames, or ear-hook designs.
• Micro Cylindrical Lithium Modules
  High-drain Li-ion cells and modules for powerful, long-lasting vibration drivers.
• High-Drain Li-ion Solutions
  Battery configurations optimized for continuous output and fast transient response.
• PCM/BMS Design & Integration
  Multi-layer safety, temperature monitoring, and compatibility with USB-C, magnetic charging, or docking bases.
• Certification & Regulatory Support
  UN38.3, IEC 62133 and related documents for transportation, regulatory filing, and market entry.

For projects exploring emerging chemistries or ultra-long cycle life, PKNERGY can also evaluate

sodium-ion battery customization
and other advanced technologies to support your future product roadmap.

FAQ: Battery Design for Bone-Conduction Hearing Devices