Battery Tab Layout for Asymmetric H-Field EMI Reduction
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Solution Overview
Problem
In small form-factor devices like wireless earbuds, the design challenge is to minimize electromagnetic interference (EMI) caused by nearfield coupling between the battery and other electronic components, which degrades audio quality and user experience.
Innovation Solution
A battery configuration with a predefined external-tab configuration and internal-tab angle is used to shape the H-field distribution asymmetrically about the symmetry axis, reducing electromagnetic coupling and EMI.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If battery size is increased to extend battery life, then battery life is improved, but electromagnetic interference increases due to larger interface area with other components
Solution Approach 1:
The patent applies asymmetry by positioning the battery tabs at non-symmetric locations and angles. The first tab is positioned at a first angle relative to the battery axis, while the second tab is positioned at a second angle, creating an asymmetric current distribution that shapes the H-field to minimize coupling with adjacent electronic components while maintaining large battery size for extended life
2Volume of moving object
If battery size is reduced to minimize device form factor, then device size is reduced, but battery life decreases
Solution Approach 1:
The patent changes the geometric parameters of the battery tab configuration - specifically the angles and positions of the tabs relative to the battery axis. This parameter optimization allows the battery to maintain compact dimensions while the asymmetric tab arrangement shapes the magnetic field to reduce EMI, enabling small form factor devices to achieve both compact size and acceptable battery life
3Volume of moving object
If battery is positioned closer to electronic components to save space, then device compactness is improved, but electromagnetic coupling increases causing audio noise
Solution Approach 1:
The asymmetric tab positioning creates an asymmetric H-field distribution that directs the magnetic field away from sensitive electronic components. By positioning tabs at specific non-symmetric angles, the patent minimizes the magnetic field intensity in regions where electronic components are located, thereby reducing electromagnetic coupling and audio noise even when the battery is positioned close to these components for compact device design
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 minimizes EMI, reducing unwanted noise artifacts and enhancing the audio quality and user experience in small form-factor devices.
Implementation Method 1
Both external tabs are positioned relative to the internal tabs to shape an H-field created by electric current running through the battery such that the H-field is asymmetrically distributed about the symmetry axis
Data Source
AI summary
The present document describes a battery configuration for directing relative H-field distributions. The battery configuration is an enclosure housing a plurality of anode and cathode layers, separated by insulation layers (e.g., a stacking cell battery, a coin cell battery, a button cell battery, etc.), with two internal tabs within the enclosure and two external tabs. The battery has a predefined external-tab configuration and a predefined internal-tab angle for reducing electromagnetic (EM) coupling. The tabs are positioned relative to one another and a symmetry axis of the battery to shape an H-field created by electric current running through the battery such that the H-field is asymmetrically distributed about the symmetry axis.