Battery Pack Leakage Detection via Impedance Sensing
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Solution Overview
Problem
Existing liquid leakage detection systems for non-aqueous electrolyte batteries, such as lithium ion secondary batteries, face challenges in accurately detecting electrolyte leaks due to non-conductive electrolytes and misrecognition of resistance changes caused by deterioration or condensation, leading to incorrect operations.
Innovation Solution
A battery pack design that includes a non-aqueous electrolyte battery cell, a casing with a leaked liquid retention region, and a separate liquid leakage sensor that detects impedance changes without using the battery's charging/discharging circuit, featuring a sensor unit with insulated electrodes and a determination unit to differentiate between electrolyte leakage and other factors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a liquid leakage sensor is used to detect electrolyte leakage in non-aqueous electrolyte batteries, then leakage detection capability is provided, but the sensor cannot detect sufficient resistance value change because non-aqueous electrolyte is not conductive
Solution Approach 1:
The patent introduces an intermediary substance (conductive gel or conductive liquid) between the sensor electrodes and the battery cell. This intermediary converts the non-conductive electrolyte leakage into a detectable signal by allowing electrical conduction through the sensor, thereby enabling resistance value change detection without directly contacting the non-conductive electrolyte
Solution Approach 2:
The patent replaces the electrical conduction-based detection method (suitable for aqueous electrolytes) with an alternative detection mechanism that works with non-conductive electrolytes. This involves using the intermediary substance to enable electrical detection, or alternatively using capacitive sensing, impedance sensing, or other non-conductive detection methods
2Measurement precision
If a liquid leakage detector is directly coupled to a battery cell, then detection sensitivity is improved, but misrecognition occurs between electrolyte leakage and battery deterioration or condensation
Solution Approach 1:
The patent segments the detection system into separate functional components: the sensor unit that contacts the battery cell, the intermediary substance layer, and the evaluation unit that analyzes the signal. This segmentation allows the sensor to maintain high sensitivity while the evaluation unit independently processes the signal to distinguish between leakage and other conditions
Solution Approach 2:
The patent implements feedback mechanisms where the evaluation unit continuously monitors sensor signals and compares them against reference values or historical data. This feedback loop enables the system to learn and distinguish between different conditions (leakage vs. condensation vs. deterioration) based on pattern recognition, thereby reducing misrecognition
3Device complexity
If the sensor uses the battery's charging/discharging circuit, then device complexity is reduced, but detection accuracy decreases due to interference from charging/d discharging operations
Solution Approach 1:
The patent extracts the liquid leakage detection function from the charging/discharging circuit by providing a separate detection circuit path. The sensor unit connects to the battery cell through a dedicated detection pathway that is electrically isolated from the power management circuitry, allowing independent operation without interference
Solution Approach 2:
The intermediary substance serves as an electrical isolation layer that enables the sensor to detect electrolyte leakage without requiring direct electrical connection to the battery terminals. This intermediary allows the detection circuit to operate independently from the charging/discharging circuit while maintaining detection capability
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
Enhances the sensitivity of liquid leakage detection and prevents misrecognition, allowing for accurate identification of electrolyte leaks and reducing false alarms caused by other factors like condensation.
Implementation Method 1
the liquid leakage sensor detects an impedance change caused by attachment of the non-aqueous electrolyte to the sensor unit
Data Source
AI summary
A battery pack which includes: a battery cell which contains a non-aqueous electrolyte, wherein the battery cell is a non-aqueous electrolyte secondary battery; a casing which stores the battery cell; and at least one liquid leakage sensor which detects liquid leakage from the battery cell, wherein the casing and/or the battery cell have a leaked liquid retention region in which the non-aqueous electrolyte tends to be retained when the non-aqueous electrolyte leaks out of the battery cell, wherein the liquid leakage sensor outputs measurement information as a detection result without using a charging/discharging circuit which charges and discharges the battery cell, and wherein at least one sensor unit of the liquid leakage sensor is provided in the leaked liquid retention region.