Battery Balancing Circuit Self-Test via Voltage Differential
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Solution Overview
Problem
Existing methods for testing balancing circuits in battery systems are costly due to the need for additional current sensors, which restrict the overall capacity of the battery system by not allowing proper charging or discharging of all cells, leading to impaired battery performance.
Innovation Solution
A method and device using a control unit to detect initial and final voltage states of battery cells, activate the balancing circuit, and determine its functionality without additional sensors by measuring voltage differences before and after balancing, utilizing existing voltmeters to assess the circuit's effectiveness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If current sensors are added to test the balancing circuit, then the testing accuracy is improved, but the system cost increases
Solution Approach 1:
The existing control unit is made to perform multiple functions: it not only controls the battery management system but also serves as the testing device for the balancing circuit. The control unit utilizes existing voltage measurements to test balancing circuit functionality without requiring additional current sensors, thus achieving multi-functionality with existing components.
Solution Approach 2:
The battery management system tests its own balancing circuit using its existing control unit and voltage measurement capabilities. The system is self-sufficient and does not require external testing equipment or additional sensors, as the control unit independently performs both battery management and balancing circuit testing functions.
2Reliability
If current sensors are installed for each battery cell, then the balancing circuit testing capability is improved, but the installation space and system complexity increase
Solution Approach 1:
The control unit is designed to perform multiple functions including battery monitoring and balancing circuit testing. By utilizing the existing voltage measurement infrastructure already present in the battery management system, the control unit can test balancing circuit functionality without requiring additional physical space for current sensors.
Solution Approach 2:
The testing function is extracted from the concept of requiring physical current sensors and is instead implemented through software/control logic within the existing control unit. This extracts the testing capability from hardware dependencies and implements it through intelligent control using existing voltage data.
3Reliability
If additional testing components are added, then the balancing circuit functionality can be verified, but the overall system cost and complexity increase
Solution Approach 1:
The battery management system performs self-diagnosis of the balancing circuit using its existing control unit. The control unit monitors voltage states before and after balancing operations and determines functional capability internally, making the system self-sufficient for testing purposes without external testing equipment.
Solution Approach 2:
The control unit implements a feedback mechanism by measuring voltage states before balancing, activating the balancing circuit, then measuring voltage states after balancing to determine if the balancing circuit functioned correctly. This closed-loop feedback approach verifies balancing circuit functionality using existing system components.
Data Source
AI summary
A method tests a balancing circuit for a battery having a plurality of battery cells. The method detects first voltage states of the battery cells by way of a control unit; activates the balancing circuit with the aim of achieving a voltage equalization of at least two of the battery cells; detects second voltage states of the battery cells by way of the control unit; and determines a functional capability of the balancing circuit based on the first voltage states and the second voltage states of the battery cells by way of the control unit.