Dynamic Cut-Off Voltage Adjustment for Li-Ion Batteries
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Solution Overview
Problem
Lithium-ion batteries often terminate discharge prematurely at high rates, leaving unused capacity due to fixed cut-off voltages, which can lead to reduced battery utilization and potential damage from lower voltages.
Innovation Solution
A method that determines the discharge rate of a lithium-ion battery and adjusts the cut-off voltage dynamically, allowing for greater capacity utilization while minimizing the risk of damage by temporarily lowering the cut-off voltage during high discharge rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a fixed cut-off voltage is used for lithium-ion batteries, then battery protection is simplified and reliability is improved, but battery capacity utilization deteriorates at high discharge rates
Solution Approach 1:
The patent implements dynamic adjustment of the cut-off voltage based on the discharge rate. The system monitors the discharge rate and temporarily lowers the cut-off voltage when high discharge rates are detected, allowing greater capacity utilization. When discharge rates return to normal, the cut-off voltage is restored to its original higher value for protection. This dynamic adaptation resolves the contradiction by making the cut-off voltage flexible rather than fixed.
Solution Approach 2:
The patent changes the electrical parameter (cut-off voltage) based on operating conditions (discharge rate). By adjusting the cut-off voltage parameter dynamically - lowering it during high discharge rates and restoring it during normal operation - the system optimizes both capacity utilization and battery protection, resolving the contradiction between fixed protection and variable performance requirements.
2Productivity
If the cut-off voltage is lowered to increase capacity utilization, then battery energy extraction is improved, but battery damage risk increases
Solution Approach 1:
The system dynamically adjusts the cut-off voltage based on real-time discharge rate monitoring. During high discharge rates, the cut-off voltage is temporarily lowered to maximize capacity utilization. When discharge rates return to normal levels, the cut-off voltage is automatically restored to its original higher protective value. This temporal differentiation allows the system to extract maximum energy when needed while maintaining protection under normal conditions.
Solution Approach 2:
The patent implements periodic monitoring and adjustment of the cut-off voltage based on discharge rate conditions. The system continuously evaluates whether high discharge rate conditions exist and adjusts the cut-off voltage accordingly, creating a rhythmic pattern of voltage adjustment that balances energy extraction with battery protection throughout the battery's operational cycle.
3Device complexity
If a fixed cut-off voltage is used, then device complexity is reduced, but adaptability to different discharge rates deteriorates
Solution Approach 1:
The patent transforms the static cut-off voltage control into a dynamic system that automatically adapts to different discharge rates. The system monitors discharge rate conditions and adjusts the cut-off voltage accordingly, enabling adaptability to varying operational demands while maintaining relatively simple control logic through predefined adjustment rules.
Solution Approach 2:
The system implements feedback control by continuously monitoring the discharge rate and using this information to adjust the cut-off voltage. The discharge rate measurement provides feedback that triggers appropriate voltage adjustments, enabling the system to adapt to different operating conditions automatically without complex external control.
Data Source
AI summary
A method can include powering circuitry via a lithium ion battery; during the powering, determining a discharge rate of the lithium ion battery; and, based at least in part on the determined discharge rate, adjusting a cut-off voltage for the lithium ion battery.