Battery Cell Balancing Resistors for Charge Level Reduction
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Solution Overview
Problem
Consumer electronics devices, such as personal computers, often remain connected to AC power for extended periods, causing lithium-ion batteries to degrade quickly due to high state of charge without usage, with no effective solutions currently available to mitigate this issue.
Innovation Solution
A system and method that utilize cell balancing resistors within the battery pack to automatically reduce the charge level of battery cells when a threshold time of non-use is detected, using a processor to control the resistors and manage the charge level without user input or external hardware/software.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the battery is kept at high state of charge for extended periods while connected to AC power, then the battery capacity is maximized for immediate use, but the battery degrades quickly and undergoes swelling
Solution Approach 1:
The system performs preliminary discharge action by activating cell balancing resistors before significant degradation or swelling occurs. The processor monitors charge state and automatically triggers discharge through resistors when thresholds are exceeded, preventing the harmful effects of prolonged high charge states before they manifest.
Solution Approach 2:
The battery management system serves itself by automatically monitoring its own charge state and initiating discharge operations when necessary. The processor within the battery pack independently determines when discharge is needed and controls the cell balancing resistors without requiring external intervention, enabling the battery to self-regulate its charge state for optimal health.
2Reliability
If cell balancing resistors are used to reduce charge level, then battery health is improved and swelling is reduced, but energy is lost as heat
Solution Approach 1:
The system converts the harmful effect of excess charge energy into beneficial battery health maintenance. By directing excess charge through cell balancing resistors, the energy that would otherwise cause degradation and swelling is instead controlledly dissipated as heat, transforming a potential harm into a protective mechanism that extends battery life.
3Ease of operation
If the system automatically controls cell balancing resistors without user input, then battery maintenance is simplified, but device complexity increases
Solution Approach 1:
The existing cell balancing resistors, originally designed for their primary function of equalizing charge across cells during charging, are made multi-functional by also using them for automatic discharge control. The processor leverages these existing components to perform both cell balancing and charge state maintenance, avoiding the need for separate discharge circuitry and minimizing additional complexity.
Solution Approach 2:
The battery management system performs self-maintenance by automatically monitoring charge states and controlling discharge operations without user intervention. The processor continuously assesses battery conditions and autonomously activates or deactivates cell balancing resistors as needed, eliminating the need for user awareness or manual battery maintenance actions.
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 approach extends the battery's lifespan and reduces cell swelling by automatically lowering the charge level when the device is not in use, using cell-balancing resistors to convert excess energy to heat, thereby maintaining battery health.
Implementation Method 1
using cell-balancing resistors to convert excess energy to heat
Data Source
AI summary
In one aspect, a device includes system components and a battery pack. The battery pack includes one or more cell balancing resistors, plural battery cells in a circuit with the one or more cell balancing resistors, at least one processor, and storage accessible to the processor. The storage includes instructions executable by the processor to determine whether a threshold amount of time has accrued during which the device has not been operated on battery power and, responsive to a determination that the threshold amount of time has accrued, employ the one or more cell balancing resistors of the battery pack to reduce the charge level of the plural battery cells.