Battery Pack Contact Fault Detection for Parallel Cell Reliability
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Solution Overview
Problem
Existing battery packs face issues with contact faults due to mechanical stress and vibrations, leading to damaged welds and uneven current distribution among batteries, which can cause overheating and damage, and existing detection methods are inadequate in preventing such faults.
Innovation Solution
A method for detecting contact faults in battery packs by applying current, determining voltage, and comparing parameters with reference values, and using temperature sensors to lock or unlock the battery pack based on temperature ranges to prevent further use if faults are detected.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If batteries are connected in parallel to form a battery pack, then the current distribution among batteries is improved, but contact faults due to mechanical stress and vibrations can still occur leading to damaged welds and uneven current distribution
Solution Approach 1:
The patent applies preliminary action by implementing a detection method that proactively identifies contact faults before they lead to harmful effects. The system continuously monitors voltage differences between cell connectors and communication cables, comparing measured values against threshold values to detect faults in advance, preventing damaged welds and uneven current distribution from developing into serious hazards
Solution Approach 2:
The patent implements feedback by creating a closed-loop monitoring system. The voltage difference detector continuously measures voltage differences, the controller compares these measurements against threshold values, and the system provides feedback about the health status of cell connectors. This feedback mechanism enables real-time detection of contact faults and allows for timely intervention before reliability deteriorates
2Reliability
If a battery becomes electrically separated from the battery pack, then the remaining batteries must operate outside their specification window, but existing detection methods are inadequate in preventing such faults
Solution Approach 1:
The patent uses an intermediary approach by utilizing the existing communication cable infrastructure as a mediator for fault detection. Instead of requiring separate complex detection hardware, the system uses the communication cable already present in the battery pack to measure voltage differences. This intermediary use of existing components enables reliable detection of battery separation and contact faults without significantly increasing device complexity
Solution Approach 2:
The patent applies self-service by enabling the battery pack's own communication infrastructure to serve the dual purpose of communication and fault detection. The voltage difference detector utilizes the communication cable and controller that are already part of the battery pack's standard configuration, allowing the system to monitor its own health status without requiring external detection equipment or significantly increasing internal complexity
3Object-affected harmful factors
If a damaged weld leads to high-resistance contact, then harmful overheating occurs, but detection and prevention mechanisms are insufficient
Solution Approach 1:
The patent replaces mechanical inspection methods with an electrical measurement system. Instead of physically inspecting welds for damage, the system uses voltage difference measurements across the cell connectors to detect contact faults. This substitution of mechanical inspection with electrical measurement enables non-intrusive, continuous monitoring of weld integrity and early detection of high-resistance contacts that could lead to overheating
Solution Approach 2:
The patent applies parameter changes by monitoring voltage difference as a diagnostic parameter for contact fault detection. The system measures voltage differences between cell connectors and communication cables, and when this voltage parameter exceeds a threshold value, it indicates a contact fault. This parameter-based approach transforms the difficult-to-detect physical condition of weld integrity into a measurable electrical parameter that can be continuously monitored and used to prevent overheating
Data Source
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AI summary
A method for identifying contact faults in a battery pack (2), wherein each battery (8) of the battery pack (2) is connected in parallel to at least one further battery (8) of the battery pack (2), comprises the following method steps: Supplying at least one current to the battery pack (2). Determining at least one voltage supplied to the battery pack (2), depending on the supply current. Determining at least one parameter on the basis of the voltage determined earlier. Comparing the parameter to a reference variable.