Battery Monitoring Circuit Using Dual Current Loops for Impedance Sensing
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Solution Overview
Problem
Conventional battery monitoring circuits require high-rated voltage sensors and complex systems to determine battery impedance, leading to increased cost and complexity.
Innovation Solution
A battery monitoring circuit with multiple current loops and a simplified method that reduces voltage at the sensor using resistors and switches, allowing for the use of low-rated voltage sensors, thereby reducing circuit complexity and cost.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional battery monitoring circuits use high-rated voltage sensors to measure battery impedance, then measurement accuracy is maintained, but device complexity and cost increase
Solution Approach 1:
The battery monitoring circuit is divided into multiple current loops (first current loop with high current, second current loop with low current for impedance measurement). By segmenting the measurement function across different loops with different current ratings, the system can use lower-rated sensors while maintaining measurement accuracy through differential measurement techniques.
Solution Approach 2:
A differential amplifier or instrumentation amplifier is introduced as an intermediary device to amplify the small voltage difference measured by the low-rated voltage sensor. This intermediary component enables accurate impedance measurement without requiring the sensor to directly handle high battery voltages, thus reducing sensor rating requirements and overall system complexity.
2Measurement precision
If conventional battery monitoring circuits use high-rated voltage sensors, then measurement capability is ensured, but cost increases
Solution Approach 1:
The voltage measurement function is segmented between multiple voltage sensors operating in different current loops. Low-rated voltage sensors are used in the second current loop for impedance measurement, while the first current loop uses appropriate sensing for charge/discharge monitoring. This segmentation allows use of cheaper, low-rated sensors instead of expensive high-rated sensors throughout the system.
Solution Approach 2:
The system changes the operating parameters of voltage sensors by operating them in a low-current environment (second current loop) during impedance measurement. This parameter change allows low-rated sensors to function effectively for their specific purpose without requiring the high voltage ratings that would be necessary if they operated in the main high-current loop.
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 proposed circuit achieves efficient battery health monitoring with reduced costs and complexity by utilizing low-rated voltage sensors and a simpler design compared to conventional systems.
Implementation Method 1
measuring the injected sinusoidal current and the voltage across the battery. The battery impedance is then estimated through use of the sinusoidal current and the measured battery voltage.
Data Source
AI summary
A method and system for determining the health of a set of batteries through the use of a battery monitoring circuit. The battery monitoring circuit including a first current loop and a second current loop. The first current loop being enabled by a first switch, a first resistor and a second switch. The second current loop being enabled by the first switch, a third switch, a voltage sensor, and the second switch.