Battery Charger Adaptive Current Control

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Solution Overview

Problem

Conventional battery chargers require manual selection of charging current, which can lead to overcharging and overheating, especially when charging batteries of different sizes, and do not account for the current state of charge, posing a risk of damage or fire.

Innovation Solution

A method that applies an electrical pulse to determine the battery capacity quickly and adjusts the charging current using a proportional controller to maintain a predetermined rate of change in voltage, ensuring safe and efficient charging.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a high charging current is used to charge large batteries quickly, then charging speed is improved, but the risk of overheating and damage increases when small batteries are connected

Engineering Contradiction:
Improvecharging speedVSAvoidoverheating and damage risk
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The system performs preliminary identification of battery capacity before charging begins. By measuring the battery's voltage response to current pulses and calculating capacity using the C-rate method, the charger determines the appropriate charging current in advance, preventing overheating before it occurs

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The charging current is dynamically adjusted based on the identified battery capacity. The system continuously monitors battery parameters and modifies the charging current in real-time, transitioning from a fixed high current approach to an adaptive current control that matches the specific battery's requirements

Inventive Principle:
Principle #15Dynamics

2Device complexity

If manual selection of charging current is used, then device complexity is reduced, but charging accuracy and safety deteriorate due to user error and lack of state of charge monitoring

Engineering Contradiction:
Improvecontrol simplicityVSAvoidcharging current accuracy
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The battery charger performs self-identification of battery capacity and automatically determines the optimal charging current without user intervention. The system autonomously measures battery parameters, calculates capacity, and adjusts charging parameters, eliminating the need for manual selection while ensuring accuracy

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The system continuously monitors battery voltage, current, and temperature during charging, using this feedback to adjust the charging current in real-time. The feedback loop ensures the charging current remains within safe limits while optimizing charging speed based on the battery's actual state

Inventive Principle:
Principle #23Feedback

3Ease of operation

If rule of thumb charging current (C/10) is used for all batteries, then ease of operation is improved, but charging efficiency deteriorates for batteries with different capacities and states of charge

Engineering Contradiction:
Improveoperational simplicityVSAvoidcharging efficiency
Core Design Contradiction:
Ease of operationVSProductivity

Solution Approach 1:

The system dynamically changes charging parameters (current, voltage, time) based on the identified battery capacity and state of charge. Instead of using a fixed C/10 rate for all batteries, the system calculates and applies optimized charging parameters specific to each battery's characteristics, significantly improving charging efficiency

Inventive Principle:
Principle #35Parameter changes

4Reliability

If automatic battery identification is implemented, then charging safety is improved, but device complexity and measurement time increase

Engineering Contradiction:
Improvecharging safetyVSAvoididentification system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The system replaces complex physical battery identification methods with electrical measurement techniques. By analyzing the battery's electrical response (voltage changes) to controlled current pulses, the system accurately determines battery capacity and characteristics using simple electrical measurements rather than complex mechanical or chemical identification methods

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentEP3271994B1A method for operating a battery charger, and a battery charger
Publication Date: 2021.04.28 CTEK SWEDEN
  • EP3271994B1 patent drawingFigure 1~2
  • EP3271994B1 patent drawingFigure 3~4
  • EP3271994B1 patent drawingFigure 5A~5B

AI summary

The present invention relates to a method for operating a battery charger, and a battery charger. The method comprising the steps of determining a capacity of the battery, determining an initial charging current, apply the calculated initial charging current as a charging current to the battery, determining the voltage change with time ΔV/Δt for the voltage over the battery, adjusting the charging current based on the ΔV/Δt.