Battery Management System Voltage Measurement Isolation
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Solution Overview
Problem
Conventional battery management systems face interference between cell balancing and voltage measurement due to shared electrical lines, leading to inaccurate voltage readings.
Innovation Solution
A battery management system that uses a control unit to sequentially measure cell voltages and perform balancing operations, employing selection switches, cell balancing switches, and a relay unit to isolate voltage measurement from balancing operations, ensuring accurate voltage measurement without interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If cell balancing and voltage measurement are performed simultaneously through shared electric lines, then both operations can be executed without waiting, but voltage measurement accuracy deteriorates due to interference and voltage drops
Solution Approach 1:
The patent segments the battery management operations by dividing cells into groups and assigning different operations to different groups at different time intervals. Specifically, odd-numbered cells perform balancing while even-numbered cells are measured, then vice versa. This temporal and spatial segmentation eliminates interference between balancing and measurement operations, resolving the contradiction between operational efficiency and measurement accuracy.
Solution Approach 2:
The patent implements periodic alternating operations where cell balancing and voltage measurement are performed in alternating time periods. During one period, odd cells are balanced and even cells are measured; during the next period, even cells are balanced and odd cells are measured. This periodic action ensures that balancing and measurement never occur simultaneously on the same electric line, maintaining measurement accuracy while achieving operational efficiency through continuous alternating execution.
2Stability of the object's composition
If cell balancing is performed on adjacent cells, then voltage differences between cells are reduced, but voltage measurement accuracy deteriorates due to current-induced voltage drops on shared electric lines
Solution Approach 1:
The patent segments cells into odd and even groups, ensuring that when balancing is performed on one group (e.g., odd cells), the adjacent cells (even cells) are being measured rather than balanced. This segmentation prevents simultaneous balancing of adjacent cells that share electric lines, eliminating the interference that causes measurement errors while still achieving cell voltage uniformity through alternating balancing operations.
Solution Approach 2:
The control unit acts as an intermediary that coordinates and schedules balancing operations to avoid interference with voltage measurements. By intelligently scheduling which cells undergo balancing at any given time based on their group assignment and current operational state, the control unit mediates between the need for cell balancing and the need for accurate voltage measurement, preventing simultaneous operations on electrically connected cells.
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
Enables accurate cell voltage measurement without affecting cell balancing, preventing voltage differences between measured and actual voltages, and allowing for efficient balancing without impacting measurement speed.
Implementation Method 1
a relay unit (120), connected to the capacitor (C1), wherein the control unit (20) turns on the relay unit (120), receives the voltage charged in the capacitor (C1), and measures the voltage of the selected cell
Data Source
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AI summary
A battery management system and method, the method including balancing cells (CELL15) and measuring the cell voltages of cells (CELL13) that are not directly adjacent to the cells being balanced. The system comprises a cell balancing unit (40), a cell selecting unit (100) and a control unit (MCU) controlling their operation.