Dual Reference Electrode Battery State of Charge Control
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Solution Overview
Problem
Existing battery state of charge determination methods are unreliable due to potential drift in reference electrode potentials during operation, leading to inaccurate SOC assessment.
Innovation Solution
A method and device utilizing two reference electrodes with different capacities, where the state of charge is determined by measuring electrode voltage between the cathode/anode and a second reference electrode with greater capacity, and adjusting the state of the first reference electrode through a current source/sink to maintain a constant potential, preventing complete or near-complete charging/discharging of the second reference electrode.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a reference electrode is used to determine the state of charge, then the state of charge can be determined, but the reference electrode potential drifts during operation leading to inaccurate measurements
Solution Approach 1:
A second reference electrode with greater capacity is introduced as an intermediary with more stable potential. This second reference electrode mediates the measurement process by providing a stable reference potential, while the first reference electrode's potential drift is compensated through periodic charging/discharging operations controlled by the device
2Reliability
If the reference electrode capacity is increased to maintain constant potential, then potential stability improves, but the device complexity increases due to additional components
Solution Approach 1:
The reference electrode system is segmented into two distinct reference electrodes with different capacities. The first reference electrode (lower capacity) is periodically charged/discharged to maintain its potential, while the second reference electrode (greater capacity) provides stable potential for measurements. This segmentation allows each electrode to have optimized characteristics for its specific function
Solution Approach 2:
The charging and discharging of the first reference electrode is performed periodically rather than continuously. The control device monitors the state of charge of the first reference electrode and applies charging/discharging current only when needed, based on comparison with threshold values. This periodic action maintains potential stability while minimizing additional complexity and energy consumption
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
Ensures reliable determination of the state of charge by maintaining a constant potential of the second reference electrode, allowing for accurate monitoring of battery operation and preventing potential drops or rises, thereby ensuring precise SOC assessment.
Implementation Method 1
a current source or a current sink are connected to the first reference electrode and the second reference electrode, such that the state of charge of the first reference electrode and the second reference electrode varies
Implementation Method 2
at least one electrode voltage is detected between the at least one cathode or anode and the second reference electrode
Data Source
AI summary
A method and a device operate an energy storage cell having a cathode, an anode, an electrolyte, a first reference electrode which has a first capacity for storing an electric charge, and a second reference electrode which has a second capacity for storing an electric charge, the second capacity being larger than the first capacity. The method detects at least one electrode voltage between the one cathode or anode and the second reference electrode; determines the charge state of the energy storage cell using the at least one electrode voltage; detects a reference voltage between the second reference electrode and the first reference electrode; connects a current source to the first reference electrode and the second reference electrode such that the charge state of the first reference electrode and the second reference electrode changes; and separates the current source from the first reference electrode and the second reference electrode. The point in time when the current source is connected and separated to or from the first reference electrode and the second reference electrode depends on the result of a comparison between the reference voltage and a specified voltage value.