Battery Swell Detection Switch for Early Li-Ion Cell Warning
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Solution Overview
Problem
Lithium-ion batteries used in portable electronic devices can swell as they age, posing safety hazards due to restricted space constraints, which can cause mechanical damage by pushing against surrounding components, and existing detection systems are inadequate in addressing this issue effectively.
Innovation Solution
A battery swell detection system that includes a circuit and a switch, such as a membrane or conductive pill switch, positioned near the battery assembly, which moves in response to swelling, completing or opening a circuit to indicate battery swelling, and is integrated with a touch sensor and printed circuit board to detect changes in capacitance or resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a rigid plastic or metal case is used to confine battery swelling, then mechanical damage to surrounding components is prevented, but the battery swelling cannot be detected early and the device space is heavily constrained
Solution Approach 1:
The dome switch is pre-positioned in a non-conductive state away from the circuit trace. When battery swelling occurs, the dome is depressed and makes contact with the trace, completing the circuit and triggering an alarm. This preliminary positioning allows early detection before significant swelling damage occurs.
Solution Approach 2:
The dome acts as an intermediary mechanical element between the battery and the detection circuit. It translates the physical swelling of the battery into an electrical signal by making contact with the circuit trace when depressed, enabling indirect detection of battery condition.
2Weight of moving object
If thin and light battery cells are used to reduce device weight and thickness, then device portability is improved, but the battery cells have less space constraint and can push on components like keyboard and touch pad when swollen
Solution Approach 1:
The detection system is pre-configured with the dome switch positioned to detect swelling at critical thresholds. This allows early warning before the thin battery cells cause damage to delicate components like keyboards and touch pads.
Solution Approach 2:
The system provides real-time feedback through the dome switch that detects battery swelling. When the dome is depressed by swelling, it completes a circuit that triggers an alarm, providing immediate feedback to alert users of potential damage to surrounding components.
3Object-affected harmful factors
If traditional rigid battery cases are used, then battery swelling is contained, but no early detection signal is generated and protection mechanisms cannot be activated timely
Solution Approach 1:
The dome serves as a mechanical intermediary that converts contained swelling into an detectable electrical signal. When the battery swells and depresses the dome, the dome's movement completes a circuit with the trace, generating an electrical detection signal that indicates swelling has occurred.
Solution Approach 2:
The invention replaces pure mechanical containment with a hybrid system that incorporates electrical detection. The mechanical dome switch translates physical swelling into an electrical signal, substituting mechanical state changes with detectable electrical changes for timely protection activation.
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 battery swelling by measuring changes in capacitance or resistance, allowing for timely intervention to prevent further swelling and potential damage, enhancing safety and reliability in portable electronic devices.
Implementation Method 1
detect changes in capacitance or resistance
Implementation Method 2
detect changes in capacitance or resistance
Data Source
AI summary
A portable electronic device may include a battery assembly, a battery swell detection unit in proximity to the battery assembly, the battery swell detection unit includes a circuit, a switch positioned to be moved by swelling of a battery cell, a processor, and memory having programmed instructions that cause the processor, when executed, to detect battery swelling based on a position of the switch.