Secondary Battery Strain Sensing for Early Pressure Anomaly Detection
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Solution Overview
Problem
Lithium-ion secondary batteries face risks of explosion or fire due to increased internal pressure, which can lead to safety valve activation and electrolyte leakage, causing damage to the battery and mounted electronic devices.
Innovation Solution
An anomaly detection system comprising a strain sensor, memory, and comparator that detects increases in internal pressure before the safety valve opens, outputting an anomaly detection signal to prevent premature activation and minimize damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the safety valve is made fragile to break easily under pressure, then the battery can release pressure to prevent explosion, but the safety valve may activate prematurely causing electrolyte leakage and device damage
Solution Approach 1:
The strain sensor detects internal pressure changes and housing expansion before the safety valve activation threshold is reached, enabling early warning and preventive action. The system performs preliminary detection of abnormal pressure buildup, allowing the device to take protective measures before electrolyte leakage occurs.
Solution Approach 2:
The detection system continuously monitors strain on the battery housing and provides real-time feedback about internal pressure conditions. When the strain sensor detects expansion indicating pressure buildup, the system generates alerts to notify users of potential safety valve activation, enabling timely response to prevent harmful effects.
2Reliability
If the safety valve is made fragile to break easily under pressure, then the battery can release pressure to prevent explosion, but it becomes difficult to detect and measure the internal pressure state before activation
Solution Approach 1:
The strain sensor acts as an intermediary element that indirectly measures internal pressure by detecting mechanical strain and housing expansion. Instead of directly measuring pressure inside the battery, the sensor monitors the physical deformation of the battery housing, which correlates with internal pressure changes, thereby solving the detection difficulty.
Solution Approach 2:
The system replaces direct mechanical pressure measurement with electrical strain detection. The strain sensor converts mechanical deformation of the battery housing into electrical signals that can be processed and analyzed, making it easier to detect and measure internal pressure states before safety valve activation.
3Reliability
If a detection system is added to monitor internal pressure, then premature safety valve activation can be prevented, but the device complexity increases
Solution Approach 1:
The battery housing structure itself serves dual purposes: it contains the battery components and simultaneously acts as the mounting structure for the strain sensor. The existing mechanical structure is utilized for detection functionality, reducing the need for additional complex support structures and minimizing overall device complexity.
Solution Approach 2:
The strain sensor serves multiple functions: it monitors housing expansion, detects internal pressure changes, and provides early warning of potential safety valve activation. This multi-functional approach consolidates several detection capabilities into a single component, reducing overall system complexity while maintaining comprehensive monitoring.
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
The system effectively detects internal pressure increases in lithium-ion secondary batteries, preventing premature safety valve activation and reducing the risk of explosion or electrolyte leakage, thus ensuring battery safety and device integrity.
Implementation Method 1
a strain sensor R12 and a resistor R11 which are connected in series
Data Source
AI summary
An anomaly detection system that outputs an anomaly detection signal before a safety valve of a secondary battery is opened is provided. The anomaly detection system includes a strain sensor, a memory, and a comparator. The memory has a function of retaining an analog potential, and the comparator has a function of comparing a potential output by the strain sensor and the analog potential retained by the memory. The strain sensor is attached to the secondary battery before use, and a predetermined potential is retained in the memory. When a housing of the secondary battery expands while the secondary battery is used, and the potential output by the strain sensor becomes higher (or lower) than the predetermined potential, an anomaly detection signal is output.