Dynamic Battery Charge Current Control

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Solution Overview

Problem

Existing battery charge controllers for Lithium-Ion batteries are limited by maximum continuous current restrictions, preventing fast charging and potentially accelerating battery aging due to lithium plating, as they do not allow charge currents higher than the predetermined maximum continuous current.

Innovation Solution

A method to dynamically determine the instantaneous maximum charge current based on overcharge capacity, temperature, and state of charge, allowing temporary high currents while preventing lithium plating, and a similar approach for discharge to manage thermal capacity and voltage limits, enabling higher pulse currents without damaging the battery.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the charge current is limited to the maximum continuous current, then the battery aging is prevented, but the charging speed is reduced

Engineering Contradiction:
Improvebattery aging preventionVSAvoidcharging speed
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent implements dynamic current adjustment by continuously monitoring the state of charge and transitioning between constant current and constant voltage charging phases. The charge controller dynamically modifies the charging parameters based on real-time battery conditions, allowing higher currents during early charging when the battery can accept them, and gradually reducing current as the battery approaches full charge, thus preventing lithium plating while maximizing charging speed

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the charging parameters (current and voltage) based on the battery's state of charge. By monitoring voltage thresholds and transitioning from constant current mode to constant voltage mode, the system optimizes the charging profile to allow higher currents when safe and reduce currents when necessary to prevent lithium deposition, resolving the contradiction between charging speed and battery protection

Inventive Principle:
Principle #35Parameter changes

2Quantity of substance

If higher charge current is applied during short time, then the energy storage capacity is improved, but the battery may be damaged

Engineering Contradiction:
Improveenergy storage capacityVSAvoidbattery safety
Core Design Contradiction:
Quantity of substanceVSReliability

Solution Approach 1:

The patent performs preliminary monitoring of battery voltage and state of charge before allowing high current charging. The charge controller continuously tracks battery parameters and only permits higher currents when the battery is in a safe state (lower state of charge), preventing lithium plating conditions from occurring in the first place

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent implements a feedback mechanism where the charge controller continuously monitors battery voltage, current, and temperature, and adjusts the charging current in real-time based on these measurements. When the battery approaches full charge or shows signs of overheating, the controller automatically reduces current to prevent damage, enabling safe utilization of higher currents for energy storage

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP2048735B1Charge management method for a battery
Publication Date: 2012.08.08 SAFT GRP SA
  • EP2048735B1 patent drawingFigure 1~2
  • EP2048735B1 patent drawingFigure 3
  • EP2048735B1 patent drawingFigure 4~5

AI summary

A method to manage charge and/or discharge of a rechargeable battery comprising at least one electrochemical cell having predetermined maximum continuous charge current (IMR_C) and/or discharge current (IMD_C) allowed, the method comprising the steps of: - measuring an instantaneous charge current (I); - defining an overcharge capacity (Cap); - determining an instantaneous maximum current allowed in charge (IMR) as a function of the overcharge capacity; and/or measuring an instantaneous discharge current (I) - defining an over thermal capacity (CapTh); - determining an instantaneous maximum pulse current allowed in discharge (IMD_max) as a function of the over thermal capacity.