Battery Discharge Termination Using Dynamic Voltage and Current Integration

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Solution Overview

Problem

Existing battery discharge termination methods based on fixed voltage do not account for changes in internal resistance as the battery ages, leading to underutilization of battery capacity and potential damage.

Innovation Solution

A method and apparatus that determine battery capacity, integrate current flow over time, and adjust discharge based on depth of discharge and voltage ranges to maximize chemical capacity and prevent damage, using a processing and control unit with measuring units to monitor and control battery operations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a fixed battery termination voltage is used, then the battery discharge termination is simple to implement, but the battery capacity is under-utilized due to internal resistance changes with age

Engineering Contradiction:
Improvedischarge termination controlVSAvoidbattery capacity utilization
Core Design Contradiction:
Ease of operationVSQuantity of substance

Solution Approach 1:

The patent applies dynamics by transitioning from a static fixed voltage threshold to a dynamic termination voltage that adapts to battery age and operating conditions. The system continuously updates the termination voltage based on the number of charge/discharge cycles and current draw, allowing the battery management system to optimize capacity utilization while preventing damage throughout the battery's lifecycle

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes key parameters including termination voltage, which is adjusted as a function of battery age (number of cycles) and current draw. By modifying these parameters dynamically rather than using fixed values, the system recovers additional usable capacity while maintaining safety margins, directly addressing the under-utilization problem

Inventive Principle:
Principle #35Parameter changes

2Device complexity

If a fixed battery termination voltage is used, then the control method is simple, but up to 30% of battery chemical capacity remains unused due to increased internal resistance in aged batteries

Engineering Contradiction:
Improvecontrol methodVSAvoidavailable battery capacity
Core Design Contradiction:
Device complexityVSQuantity of substance

Solution Approach 1:

The patent applies preliminary action by determining the battery's age through charge/discharge cycle counting before discharge operations begin. This advance knowledge allows the system to pre-calculate appropriate termination voltages and safety margins specific to the battery's age, enabling optimized capacity utilization from the start of each discharge cycle rather than using generic fixed thresholds

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent implements feedback mechanisms that monitor battery performance, count charge/discharge cycles, and measure current draw. This feedback information is used to continuously update the termination voltage calculation, creating a closed-loop system that adapts to battery aging and operating conditions to maximize available capacity while maintaining safety

Inventive Principle:
Principle #23Feedback

3Reliability

If discharge is terminated at a fixed voltage, then battery damage is avoided, but battery run-time is reduced due to premature termination

Engineering Contradiction:
Improvebattery damage preventionVSAvoidbattery run-time
Core Design Contradiction:
ReliabilityVSDuration of action of moving object

Solution Approach 1:

The patent applies dynamics by implementing a dynamic termination voltage that evolves with battery age and operating conditions. This dynamic approach allows the system to maintain reliable damage prevention through safety margins while extending run-time by recovering capacity that would otherwise be prematurely terminated under fixed voltage schemes

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the termination voltage parameter as a function of battery age and current draw, allowing the system to extend usable discharge capacity. By adjusting this parameter dynamically, the system achieves both objectives: maintaining reliability through appropriate safety margins while increasing run-time by utilizing additional available capacity in aged batteries

Inventive Principle:
Principle #35Parameter changes

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 effectively maximizes battery usage by terminating discharge when maximum capacity is reached or minimum voltage is maintained, preventing over-discharge and increasing battery run-time, especially in aged batteries.

Implementation Method 1

integrating battery current flow over a time interval to determine an integrated charge value

Methodology Applied
Scientific EffectElectrical current integration:

Implementation Method 2

A first measuring unit coupled with the battery and with the processing and control unit. The first measuring unit determines current flow from the battery during the first battery operation. A second measuring unit coupled with the battery and with the processing and control unit. The second measuring unit determines a battery voltage across the battery.

Methodology Applied
Scientific EffectElectrical measurement:

Data Source

PatentEP1920517B1Method and apparatus for operating a battery to avoid damage and maximize use of battery capacity
Publication Date: 2014.10.15 TEXAS INSTRUMENTS INC
  • EP1920517B1 patent drawingFigure 1~2
  • EP1920517B1 patent drawingFigure 3~4
  • EP1920517B1 patent drawingFigure 5~6

AI summary

A method for terminating battery discharge to avoid battery damage and maximize battery usage includes the steps of: (a) determining battery capacity (204); (b) storing a capacity result of the capacity determining (206); (c) determining battery voltage (208); (d) during a monitored battery operation, integrating battery current flow over a time interval to determine an integrated charge value at an end-of-interval-time; (e) determining an extant depth of discharge at the end-of-interval-time; (f) if the extant depth of discharge is neither within a first range of a maximum depth of discharge nor the battery voltage is within a second range of a minimum battery voltage, carrying out steps (d) through (f); (h) if the extant depth of discharge is within the first range of the maximum depth of discharge or if the battery voltage is within the second range of the minimum battery voltage(210, 212, 214), terminating the monitored battery operation (220).