EV Drive Battery Charging Limits for Imminent Cell Defects
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Solution Overview
Problem
Hybrid or electric vehicle batteries are prone to internal short-circuits due to impurities and foreign particles, leading to potential fires and overall damage, with existing diagnostic methods often failing to detect defects in time for preventative action.
Innovation Solution
A system comprising a monitoring device and charging control device that detects imminent cell defects and sets reduced maximum charging voltage and state of charge to prevent short-circuits, allowing the vehicle to operate safely and reducing the risk of fires by discharging the battery and limiting further charging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a high-voltage store with battery cells is used to store electrical energy, then the energy density and power are improved, but the risk of internal short-circuits and cell defects increases due to impurities and foreign particles
Solution Approach 1:
The system performs preliminary diagnosis of cell defects by monitoring spontaneous discharge currents before actual short-circuits occur. The receiving device detects status information indicating imminent defects, and the charging control device proactively reduces maximum charging voltage and state of charge limits before defects develop, preventing rather than merely responding to failures.
Solution Approach 2:
The system continuously monitors cell status through the receiving device that detects spontaneous discharge currents and other status information. This feedback loop allows the charging control device to adjust charging parameters in real-time based on detected cell conditions, dynamically responding to changing cell states to prevent defects.
2Device complexity
If symptomatic diagnosis is used to detect cell defects, then the device complexity is reduced, but the detection time is delayed until after defects have occurred
Solution Approach 1:
The system monitors spontaneous discharge currents and other status information continuously to detect early signs of cell defects before they manifest as full short-circuits. This preliminary detection approach identifies imminent defects through subtle changes in discharge patterns, enabling early intervention before catastrophic failures occur.
Solution Approach 2:
The system uses the cell's own spontaneous discharge current as a diagnostic indicator. By monitoring the natural discharge behavior of cells during storage or idle periods, the system extracts defect information from the cell's intrinsic characteristics without requiring external test equipment, simplifying the diagnosis system while enabling early defect detection.
3Reliability
If the maximum charging voltage and state of charge are reduced for cells with imminent defects, then the safety and reliability are improved, but the energy capacity utilization decreases
Solution Approach 1:
The charging control device applies different charging parameters to different cells based on their individual status. Cells diagnosed with imminent defects receive reduced maximum charging voltage and state of charge limits, while healthy cells continue to charge at full capacity. This localized quality approach ensures safety for affected cells without unnecessarily limiting the overall energy capacity utilization of the high-voltage store.
Data Source
AI summary
A system for a drive energy store of a hybrid or electric vehicle is provided. The system includes a receiver which is designed to receive state information of the drive energy store, the state information specifying whether a defect is present or imminent in the drive energy store; and a charging controller, which is designed to adjust a maximum charging voltage and/or a maximum state of charge for a charging process of the drive energy store by a recovery mechanism and/or a load point shift and/or an external charging station to a reduced value if the state information indicates that the defect is imminent.