TWS earbud battery market: A precise orchestration of dual batteries
True wireless stereo (TWS) earbuds are among the most widely adopted wearable devices. Unlike smartwatches, TWS earbuds use a dual‑battery system – the earbud batteries provide playback endurance per charge, while the charging case supplies reserve energy for multiple full recharges. The design logic, capacity specifications, and testing requirements for these two battery types differ significantly.
Performance characteristics of TWS earbud batteries
Earbud battery capacities typically range from 30 to 60 mAh, while charging case batteries provide an additional 300‑525 mAh.
Form factor evolution: From pouch to steel‑case button cells
TWS earbud batteries are transitioning from traditional pouch cells to steel‑case button cells. The vivo TWS Air3 Pro, for example, uses a MIC‑POWER steel‑case button cell (model M1054S1) with a nominal voltage of 3.85V, rated capacity of 40 mAh, and energy of 0.154 Wh. Steel‑case button cells offer higher structural strength, better sealing, and superior space utilization compared to pouch cells, making them particularly suitable for volume‑sensitive devices like TWS earbuds.
High energy density and compact packaging
TWS earbuds require sufficient energy storage within an extremely limited space. Charging case batteries, meanwhile, prioritize a balance between capacity and cost – the vivo TWS 5 charging case battery has a typical capacity of 525 mAh with a charge limit voltage of 4.45V. The BW‑C7 lithium‑ion battery has a nominal voltage of 3.8V, rated capacity of 513 mAh, and energy of 1.99 Wh.
Charge/discharge rate differences
Earbud batteries must support sustained discharge over extended periods (4‑12 hours per charge), while charging case batteries require higher charging efficiency (typically fully charged in 1‑1.5 hours).
What equipment is needed to test TWS earbud batteries?
μA‑level high‑precision low‑current testing
TWS earbud batteries have extremely small capacities (30‑60 mAh) and standby currents as low as microampere levels. Testing equipment must achieve µA‑level current measurement accuracy. Specialized systems such as the NEWARE CT‑4008Q‑5V100mA support four ranges with 0.01% FS accuracy, specifically designed for TWS earbud battery testing.
Dedicated battery fixtures
TWS earbud batteries come in various form factors – pouch cells require polymer fixtures, while button/coin cells require spring‑loaded pin fixtures. Testing equipment must be equipped with appropriate dedicated fixtures to ensure reliable test connections.
DCIR testing and dQ/dV analysis
DCIR testing is an important method for assessing battery health. The dQ/dV differential capacity analysis function reduces manual calculations and saves data analysis time.
Cycle life and rate charge/discharge testing
TWS earbud batteries undergo frequent charge/discharge cycles, so testing equipment must support cycle life testing, rate charge/discharge testing, and pulse simulation testing.
Multi‑channel parallel testing
TWS earbud battery production testing often requires high‑volume parallel testing, so equipment must support independent multi‑channel control.
