Battery Internal Temperature Estimation via AC Phase Difference
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Solution Overview
Problem
High-power and large-capacity battery packs used in electric and hybrid cars generate significant heat during charging and discharging, necessitating precise temperature measurement to ensure efficient operation and longevity, but existing methods are inadequate for accurately estimating internal battery temperatures.
Innovation Solution
A battery temperature estimating apparatus and method using an AC power supply to measure phase differences between AC current and voltage, selecting an oscillation frequency to minimize electrochemical impedance, and employing a temperature estimation equation to correlate state of charge (SoC) and internal temperature for accurate temperature estimation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If high-power and large-capacity battery packs are used to increase power output, then the power and capacity of the battery system are improved, but the heat generation during charging and discharging increases, making temperature measurement and heat management more difficult
Solution Approach 1:
The patent replaces direct physical temperature measurement methods with an electrical measurement approach. By measuring the phase difference between AC current and voltage, the system can estimate internal battery temperature without physical contact or additional thermal sensors, thus resolving the contradiction between high power output and heat management difficulty
Solution Approach 2:
The patent introduces phase difference as an intermediary parameter to indirectly measure internal temperature. Instead of directly measuring temperature in high-power batteries, the system uses electrical phase characteristics as a mediator to infer temperature conditions, enabling effective heat management in high-power battery systems
2Measurement precision
If conventional temperature measurement methods are used, then the measurement system is simple, but the measurement precision of internal battery temperature is insufficient
Solution Approach 1:
The patent substitutes complex physical temperature sensing systems with an electrical phase measurement approach. By using AC impedance measurement and phase difference analysis, the system achieves precise internal temperature measurement without requiring complex thermal sensor arrays or contactless thermal imaging equipment
Solution Approach 2:
The patent utilizes the battery's own electrical characteristics (AC impedance and phase response) to measure its internal temperature. The battery essentially measures itself through its electrical response to AC excitation, eliminating the need for external measurement systems while achieving high measurement precision
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
The solution enables precise internal temperature estimation of batteries, allowing for effective heat management, extended battery lifespan, and improved energy efficiency by controlling charging and discharging processes based on accurate temperature data.
Implementation Method 1
select an oscillation frequency for the AC power to substantially minimize an impedance of an electrochemical reaction at electrodes of the battery
Implementation Method 2
measuring a phase difference between an AC current and an AC voltage of the battery
Data Source
AI summary
A battery temperature estimating apparatus, the apparatus includes an alternating current (AC) power supply configured to apply AC power to a battery; a phase difference measurer configured to measure a phase difference between an AC current and an AC voltage of the battery; and an internal temperature estimator configured to estimate an internal temperature of the battery based on the measured phase difference and a state of charge (SoC) of the battery.