Battery Charger Cell-Level Bypass Control

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Solution Overview

Problem

Existing chargers for accumulators do not effectively protect battery cells from overcharging, leading to reduced service life and environmental concerns due to material consumption, and lack efficient monitoring and control mechanisms.

Innovation Solution

A charger with a controllable switch and galvanically isolated signaling channels allows bypassing charging current to each battery cell, comparing voltages with reference values to prevent overcharging and notify a higher-level controller of critical conditions, using a two-wire signaling bus for state-of-charge representation and error reporting.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a common charging current is supplied to all battery cells in series, then the charging process is simple, but some battery cells may be overcharged while others are not fully charged

Engineering Contradiction:
Improvecharging process simplicityVSAvoidbattery cell charging uniformity
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent divides the charging system into individual cell-level control units, with each battery cell having its own controllable switch and voltage comparison circuit. This segmentation allows independent monitoring and control of charging current for each cell, ensuring uniform charging while maintaining overall system simplicity through modular design.

Inventive Principle:
Principle #1Segmentation

2Reliability

If the charging current is continuously monitored and controlled for each battery cell, then overcharging is prevented, but the device complexity increases

Engineering Contradiction:
Improveovercharging protectionVSAvoidcontrol system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

Each battery cell is equipped with its own voltage comparison circuit and controllable switch that automatically regulate the charging current based on local voltage measurements. This self-service approach eliminates the need for complex centralized control, reducing overall system complexity while ensuring reliable overcharging protection for each cell.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent implements local feedback control at each battery cell, where the voltage comparison circuit continuously compares the battery cell voltage with a reference voltage and automatically adjusts the controllable switch to maintain proper charging current. This decentralized feedback mechanism provides robust overcharging protection without requiring complex system-wide control algorithms.

Inventive Principle:
Principle #23Feedback

3Measurement precision

If galvanically isolated signaling channels are implemented for each battery cell, then accurate state monitoring is achieved, but the signaling system complexity increases

Engineering Contradiction:
Improvestate of charge monitoring accuracyVSAvoidsignaling system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent combines multiple galvanically isolated signaling channels into a single shared communication bus that carries aggregated state information from all battery cells. This merging approach maintains the galvanic isolation benefits for accurate monitoring while reducing signaling system complexity by eliminating redundant separate channels for each cell.

Inventive Principle:
Principle #5Merging (Combining)

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 solution extends battery life by preventing overcharging, reduces material consumption, and enhances environmental protection by enabling precise control and monitoring of charging processes, ensuring safe and efficient charging operations.

Implementation Method 1

an arrangement for controlling the charging current for a rechargeable battery cell, the arrangement having a controllable switch with which the charging current at the battery cell can be routed past it, in particular as a bypass current

Methodology Applied
Scientific EffectElectrical conduction: Conduction (electrical)

Implementation Method 2

a means being provided for comparing a first voltage value, which corresponds to the voltage present at the battery cell, with a reference voltage value, the output signal of which is fed to the controllable switch as a control signal

Methodology Applied
Scientific EffectVoltage comparison:

Implementation Method 3

also a galvanically isolated signaling channel, via which an analog value is transmittable

Methodology Applied
Scientific EffectGalvanic isolation:

Data Source

PatentEP2676349B1Charger for a battery
Publication Date: 2018.10.31 SEW EURODRIVE GMBH & CO KG
  • EP2676349B1 patent drawingFigure 1
  • EP2676349B1 patent drawingFigure 2

AI summary

The invention relates to a charger for an accumulator which has accumulator cells connected in series, said charger comprising an arrangement that controls the charging current for an accumulator cell and that has a controllable switch which allows the charging current to be conducted past the accumulator cell, in particular as a bypass current, with a means being provided to compare a first voltage value, corresponding to the voltage across the accumulator cell, to a reference voltage value, the output signal produced being supplied, as a control signal, to the controllable switch and additionally to a galvanically-isolated signalling channel by means of which an analogue value can be transmitted.