Transformer Cell-Balancing Circuit for Battery Current Fault Detection
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Solution Overview
Problem
Conventional power storage devices face challenges in accurately detecting current changes due to high power loss from voltage divider resistors, leading to decreased capacity and potential erroneous abnormality detection in current detection units.
Innovation Solution
A power storage management device utilizing a voltage equalization circuit with transformers and switch units to determine abnormality in current detection units by analyzing voltage changes across power storage elements, reducing the need for separate current paths and minimizing power loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the resistance value of the voltage divider resistor is set to a small value to increase current flow for accurate detection, then the current detection precision is improved, but the power loss increases and remaining capacity decreases
Solution Approach 1:
The patent introduces a voltage equalization circuit as an intermediary system that uses transformers to transfer voltage information from individual battery cells to a detection point. This mediator approach allows current detection without requiring high current flow through the voltage divider resistor, thereby reducing power loss while maintaining detection accuracy through voltage measurement of the equalization current.
Solution Approach 2:
The patent replaces the conventional current detection method (which relies on measuring voltage across a resistor requiring high current flow) with a voltage-based detection method using the voltage equalization circuit. By measuring voltage in the equalization circuit instead of current in the main power path, the system achieves detection functionality with minimal power loss.
2Reliability
If a separate voltage divider resistor and relay are used for abnormality detection, then the detection capability is improved, but the device complexity increases
Solution Approach 1:
The patent makes the voltage equalization circuit serve multiple functions: it performs its primary voltage equalization function during charging/discharging while simultaneously enabling current detection and abnormality detection functions. By integrating these detection capabilities into the existing equalization circuit infrastructure, the system avoids adding separate dedicated detection circuits, thereby maintaining reliability while reducing overall device complexity.
Solution Approach 2:
The patent combines the abnormality detection function with the voltage equalization circuit by having the control unit analyze voltage changes in the equalization circuit during normal operation. This merging of functions eliminates the need for separate detection hardware components, reducing circuit complexity while maintaining the ability to detect current detection unit abnormalities.
3Loss of energy
If the voltage equalization circuit is used for abnormality detection, then the power loss is reduced, but the measurement precision of current detection may be affected
Solution Approach 1:
The patent employs feedback mechanisms where the control unit continuously monitors voltage changes in the voltage equalization circuit and compares them against expected values based on the switching states of equalization switches. This feedback approach allows the system to accurately determine current detection unit abnormalities by detecting deviations from normal voltage patterns, maintaining measurement precision despite using the low-power equalization circuit for detection.
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 approach allows for accurate abnormality detection in current detection units and voltage equalization circuits, enhancing the power storage device's efficiency and capacity while minimizing power loss and erroneous determinations.
Implementation Method 1
a voltage equalization circuit that includes a plurality of transformers provided corresponding to each of the plurality of power storage elements, each of the plurality of transformers including a first winding connected in parallel with each of the power storage elements and a second winding connected in parallel with the power storage unit and the current detection unit
Data Source
AI summary
A power storage management device includes: a voltage detection unit; a current detection unit; and a voltage equalization circuit that includes a plurality of transformers including a first winding connected in parallel with each of the power storage elements and a second winding connected in parallel with the power storage unit and the current detection unit, a plurality of switch units including at least one of a first switch connected in series to the first winding and a second switch connected in series to the second winding. When a first abnormality determination condition is satisfied, a process corresponding to an abnormality detection of the current detection unit is performed, the first abnormality determination condition including the necessary condition that a detection result of the current detection unit caused by the on/off operation of the switch units corresponding to the target power storage elements is outside a normal current range.