Battery Charging Control Using Impedance-Based Temperature Feedback
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Solution Overview
Problem
The charging performance of batteries in portable electronic devices varies with temperature, and existing technologies lack effective methods to maintain optimal temperature ranges during charging, affecting efficiency and longevity.
Innovation Solution
A system that includes charging circuitry to detect battery impedance and temperature, and a heating arrangement to maintain the battery within a predefined temperature range by controlling the charging current and voltage based on impedance and state of charge/health, using electrochemical impedance spectroscopy to infer temperature and adjust heating accordingly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If charging is performed at high current to improve charging speed, then productivity is improved, but temperature increases causing charging performance to deteriorate
Solution Approach 1:
The system continuously monitors battery impedance and infers temperature from impedance changes. Based on the inferred temperature, the charging circuitry dynamically adjusts charging current in real-time, creating a closed-loop feedback control system that prevents overheating while maximizing charging speed within safe temperature limits.
Solution Approach 2:
The system changes charging parameters (current, voltage) based on inferred battery temperature. When temperature is low, higher current is applied for fast charging; when temperature approaches limits, current is reduced. This dynamic parameter adjustment resolves the contradiction between charging speed and temperature control.
2Productivity
If battery temperature is maintained within optimal range to improve charging performance, then charging efficiency is improved, but device complexity increases due to additional control systems
Solution Approach 1:
The system uses the battery's own impedance characteristics to infer its temperature without requiring external temperature sensors. The battery essentially serves its own monitoring function, eliminating the need for separate sensing components and reducing overall system complexity while maintaining precise temperature-based charging control.
Solution Approach 2:
The impedance measurement serves multiple functions: it characterizes battery state of charge, health, and temperature simultaneously. This multi-functionality allows the system to achieve temperature-based charging control without adding dedicated temperature sensing infrastructure, thereby improving charging efficiency without proportionally increasing complexity.
3Measurement precision
If impedance detection is performed across multiple frequencies to improve temperature inference accuracy, then measurement precision is improved, but use of energy increases
Solution Approach 1:
Instead of continuous multi-frequency impedance scanning, the system performs impedance measurements periodically at selected frequency points. This periodic sampling approach maintains sufficient temperature inference accuracy while significantly reducing the energy consumption compared to continuous full-spectrum impedance spectroscopy.
Solution Approach 2:
The system performs impedance measurements at a limited set of strategically selected frequency points rather than across the entire frequency spectrum. This partial measurement approach provides adequate temperature inference accuracy for charging control purposes while minimizing the energy required for detection, avoiding the excessive action of complete spectral analysis.
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 system optimizes battery charging performance by maintaining the battery within a predetermined temperature range, improving charging efficiency and longevity by dynamically adjusting charging parameters based on real-time impedance and temperature measurements.
Implementation Method 1
The charging circuitry may be configured to detect the impedance of the battery across a plurality of different frequencies or frequency ranges, and to infer the temperature of the battery based on the detected impedance across the plurality of different frequencies or frequency ranges.
Implementation Method 2
The heating arrangement may comprise an array of resistive elements disposed, in use of the system, in proximity to the battery.
Data Source
AI summary
A system for controlling charging of a battery, the system comprising: charging circuitry for supplying a charging current or voltage to the battery, wherein the charging circuitry is configured to periodically detect an impedance of the battery and to control the charging current or voltage based on the detected impedance.