Battery OCV Detection Using Intermediary Capacitor Balancing
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Solution Overview
Problem
Existing methods for detecting abnormal battery cells in electric vehicles face accuracy issues due to variations in open circuit voltage (OCV) caused by non-periodic charging and discharging processes and varying driving environments, leading to reduced detection accuracy.
Innovation Solution
A mechanism that periodically complements the charging and discharging of multiple batteries through intermediary capacitors using bidirectional DC-DC converters, allowing for accurate OCV measurement by stabilizing voltage conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If periodic charge/discharge control operations are performed through power conversion modules, then measurement precision of OCV is improved, but device complexity increases
Solution Approach 1:
An intermediary capacitor is introduced between the first and second batteries to facilitate controlled charge/discharge operations. The capacitor acts as a temporary energy storage medium, enabling the batteries to charge and discharge through it without direct connection, thus allowing periodic OCV measurement operations while managing system complexity through a dedicated intermediary component.
Solution Approach 2:
The system performs periodic charge/discharge control operations where the first and second batteries are alternately charged and discharged through the power conversion modules and intermediary capacitor. This periodic action stabilizes voltage conditions and enables accurate OCV measurements at specific intervals, transforming a continuous complex monitoring problem into discrete periodic measurement events.
2Measurement precision
If battery switch is opened to isolate batteries for measurement, then measurement precision is improved, but productivity decreases due to operational interruptions
Solution Approach 1:
The system performs charge/discharge control operations and obtains OCV measurements during periods when the battery switch is already open (e.g., when vehicle ignition is off). By utilizing pre-existing operational states rather than interrupting normal operation, the system achieves accurate measurements without causing productivity losses from unnecessary interruptions.
Solution Approach 2:
The first and second batteries charge and discharge through the intermediary capacitor in a self-contained manner during measurement operations. This self-service charge/discharge mechanism allows the system to perform its own calibration and measurement without requiring external charging infrastructure or disrupting the vehicle's normal power supply operations.
3Reliability
If multiple power conversion modules are used for complementary charge/discharge, then reliability of battery management is improved, but device complexity increases
Solution Approach 1:
The first and second power conversion modules serve multiple functions: they perform power conversion between batteries and the intermediary capacitor, enable controlled charge/discharge operations for OCV measurement, and can operate independently or in coordination. This multi-functionality increases reliability by providing redundant capabilities while managing complexity through versatile component design.
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
Improves the accuracy of detecting abnormal battery cells by stabilizing voltage conditions and enabling precise OCV measurement, enhancing the reliability of battery management systems.
Implementation Method 1
a first power conversion module that performs power conversion between the first battery and an intermediary capacitor, a second power conversion module that performs power conversion between the second battery and the intermediary capacitor
Implementation Method 2
a first power conversion module that performs power conversion between the first battery and an intermediary capacitor, a second power conversion module that performs power conversion between the second battery and the intermediary capacitor
Data Source
AI summary
A battery apparatus, including a battery switch that allows or blocks an electrical connection between a first battery and a second battery, a first power conversion module that performs power conversion between the first battery and an intermediary capacitor, a second power conversion module that performs power conversion between the second battery and the intermediary capacitor, and a processor configured to control the first and second power conversion modules so that the first and second batteries are complementarily charged and discharged via the intermediary capacitor in an open state of the battery switch and obtains characteristic parameters of the first and second batteries after complementarily charging and discharging the first and second batteries is completed.