Transformer-Based Cell Sensing Circuit for Battery Management
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Solution Overview
Problem
High capacity batteries in electric vehicles and home systems face thermal and performance issues due to cell failures, necessitating effective monitoring of state of health (SOH) and state of charge (SOC) to ensure reliable power supply.
Innovation Solution
A cell management module with a transformer-based cell-sensing circuit that pulses a signal through a transformer winding to measure current and infer cell voltage, allowing for parallel connection of multiple cell-sensing circuits and active balancing of power cells, reducing complexity and cost while enhancing monitoring and management capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional voltage measurement circuits are used for each power cell, then accurate SOH and SOC monitoring is achieved, but device complexity and cost increase significantly
Solution Approach 1:
Multiple cell-sensing circuits are merged into a single circuit that can sequentially measure multiple power cells. The circuit uses a multiplexer or switching mechanism to connect different cells to the measurement components, allowing one circuit to perform the function of multiple circuits while maintaining measurement accuracy for each cell.
Solution Approach 2:
The cell-sensing circuit is designed as a universal multi-functional unit that can measure voltage, infer SOH, and determine SOC for any power cell in the series. By making the circuit universal, the same hardware can serve multiple purposes and multiple cells, reducing the overall number of components needed in the battery management system.
2Reliability
If individual cell monitoring circuits are implemented for each power cell, then reliable SOH and SOC assessment is achieved, but manufacturing cost increases
Solution Approach 1:
The patent combines multiple monitoring functions and multiple cell measurement capabilities into a single integrated circuit design. By merging the sensing elements, signal conditioning circuits, and processing logic into one unit that can handle multiple cells, the bill of materials is reduced and assembly complexity is lowered, directly decreasing manufacturing cost while preserving reliability.
Solution Approach 2:
Instead of creating physically separate circuits for each cell, the patent uses a single circuit design that can be programmatically or electrically configured to monitor different cells. The circuit architecture is copied virtually through control logic rather than physically through duplicate hardware, achieving the same reliability function at lower cost.
3Device complexity
If passive voltage measurement is used, then circuit simplicity is maintained, but active balancing capability is lost
Solution Approach 1:
The cell-sensing circuit is designed with multi-functionality, serving both as a measurement device and an active balancing device. The same circuit components that measure voltage can also source or sink current to balance cell charges by connecting to balancing circuits or load modules, enabling the system to adapt to different operational modes without requiring separate dedicated circuits.
Solution Approach 2:
The circuit transitions dynamically between measurement mode and balancing mode. During normal operation, it performs passive voltage monitoring; when cell voltage differences exceed thresholds, it actively engages balancing functions by adjusting current flow. This dynamic behavior allows the circuit to maintain simplicity during measurement while providing adaptability when balancing is required.
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 efficient monitoring and balancing of power cells, reducing the likelihood of insufficient power supply and extending battery life by accurately assessing SOH and SOC, thereby improving the reliability and performance of high-capacity battery systems.
Implementation Method 1
a transformer including a first winding and a second winding inductively coupled to the first winding
Data Source
AI summary
A cell management module for a power supply module including a plurality of power cells includes at least one cell-sensing circuit and a current measurement circuit connected to the at least one cell-sensing circuit. The at least one cell-sensing circuit includes a transformer having a first winding and a second winding inductively coupled to the first winding. A first sub-circuit of the cell-sensing circuit includes the first winding of the transformer and is operable to selectively pulse a first signal through the first winding. A second sub-circuit of the cell-sensing circuit includes the second winding of the transformer and one of the power cells of the power supply module. The current measurement circuit is connected to the first sub-circuit of the at least one cell-sensing circuit and infers a voltage of the power cell based on a measured current of the first signal.