Battery Discharge Circuit for Swelling Prevention
Solution Overview
Problem
Rechargeable Lithium-ion batteries pose safety hazards and risk of swelling due to internal gas buildup and slow self-discharge, especially under extreme charge or discharge conditions, leading to potential casing rupture and rendering the battery unserviceable.
Innovation Solution
Incorporating circuitry that shorts the battery to ground or accelerates discharge once a low voltage threshold is reached, preventing further self-discharge and reducing the risk of swelling by managing battery voltage and power usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If the battery is allowed to self-discharge slowly over time, then the battery can remain in a low-power state, but the battery voltage continues to drop below safe thresholds causing swelling and damage
Solution Approach 1:
The circuit proactively discharges the battery before the voltage drops to dangerous levels. By initiating discharge at a predetermined safe threshold (e.g., 2.8V per cell) rather than waiting for the battery to naturally self-discharge, the system prevents voltage from reaching harmful levels that would cause swelling or damage, thus resolving the contradiction between extended storage and safety.
2Reliability
If circuitry is added to monitor and discharge the battery, then battery safety is improved, but device complexity increases
Solution Approach 1:
The battery system monitors its own voltage state and autonomously initiates discharge when the voltage reaches the predetermined threshold. The circuit uses the battery's own electrical properties to detect its state and trigger discharge without requiring external monitoring systems, thereby improving safety while minimizing added complexity.
Solution Approach 2:
The circuit changes the discharge parameter (current flow) based on the battery voltage parameter. When voltage exceeds the threshold, the circuit transitions from a high-impedance state to a low-impedance discharge state, creating a simple voltage-threshold-based control mechanism that achieves safety without complex control logic.
3Use of energy by moving object
If the battery discharges to very low voltage, then maximum energy utilization is achieved, but the battery swells and becomes unserviceable
Solution Approach 1:
The circuit applies a counter-action (discharge current) in advance to prevent the harmful effect (swelling) from occurring. By actively discharging the battery when voltage reaches the threshold rather than allowing natural self-discharge to continue, the system prevents voltage from dropping to levels that would cause gas buildup and swelling, thus protecting the battery while still utilizing available energy.
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
This solution effectively prevents battery swelling and maintains safety by ensuring controlled discharge, extending the battery's usable life and reducing the risk of damage from continued self-discharge beyond a critical voltage threshold.
Implementation Method 1
the battery can swell and break its casing under such conditions as well as others, such as a relatively slow self-discharges over a period of time
Data Source
AI summary
Battery malfunction is limited by accelerating battery discharge once battery voltage reaches a low voltage threshold. This can be done programmatically and/or using a hardware arrangement that shorts the battery to ground when the low voltage threshold is reached.