Coin Cell Tab Configuration for EMI Reduction
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Solution Overview
Problem
In small form factor devices like wireless earbuds, larger batteries to extend life cause electromagnetic interference (EMI) issues due to nearfield coupling, leading to unwanted electromagnetic noise that degrades audio quality.
Innovation Solution
A battery configuration with predefined external and internal tab configurations, where the external tabs are positioned relative to the internal tabs to reduce the H-field and E-field generated by electric current, creating a low-field zone to minimize EM coupling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If a larger-size battery is used to extend battery life, then the battery life is improved, but electromagnetic interference increases due to nearfield coupling with packaged components
Solution Approach 1:
The patent applies local quality by specifically configuring the tab positions and orientations at particular locations on the battery can. The external tabs are positioned at specific angular positions (e.g., 0 degrees and 180 degrees) and have specific orientations relative to the battery can axis, creating localized field cancellation zones that reduce EMI in critical areas near packaged components while maintaining overall battery performance.
Solution Approach 2:
The patent changes geometric parameters of the battery tab configuration, including the angular position of external tabs relative to the battery can, the orientation angles of tabs, and the dimensional ratios between tab lengths and battery can dimensions. These parameter changes optimize the electromagnetic field distribution to minimize coupling with nearby components while preserving battery life.
2Duration of action of moving object
If the battery size is increased to extend battery life, then the battery life is improved, but the device size increases which conflicts with small form factor requirements
Solution Approach 1:
The patent optimizes the geometric parameters of the battery configuration, including tab positions, orientations, and dimensional ratios, to maximize battery life within a constrained volume. By carefully selecting these parameters, the design achieves extended battery life without proportionally increasing the overall device size, as the tab configuration optimizations do not add significant volume.
3Object-affected harmful factors
If external tabs are positioned to reduce electromagnetic interference, then electromagnetic interference is reduced, but the manufacturing precision requirements increase
Solution Approach 1:
The patent specifies particular parameter values for tab configuration (such as tabs positioned at 0 and 180 degrees, with specific orientation angles) that provide robust EMI reduction. These parameter selections are designed to achieve effective field cancellation while maintaining reasonable manufacturing tolerances, avoiding overly stringent precision requirements that would complicate production.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration effectively reduces electromagnetic interference, minimizing e-noise and enhancing user experience by reducing harmonics associated with 800 Hz, 1600 Hz, and 3200 Hz, thereby improving the effectiveness and efficiency of small form factor devices.
Implementation Method 1
Both external tabs are positioned relative to the internal tabs to reduce an H-field and/or an E-field created by electric current running through the coin cell
Data Source
AI summary
The present document describes a battery configuration for reducing electromagnetic interference (EMI). The battery configuration includes a coin cell (e.g., stacking battery cell, button cell) with predefined external-tab configurations and a predefined internal-tab angle for reducing electromagnetic (EM) coupling. In particular, internal tabs are positioned to be separated by an angle (e.g., a predefined internal-tab angle) of approximately 90 degrees. External tabs include (i) a first external tab connected to a side of the coin cell and extending to overlap a top surface of the coin cell and (ii) a second external tab connected to the top surface of the coin cell. Both external tabs are positioned relative to the internal tabs to reduce an H-field and/or an E-field created by current running through the coin cell.