Battery Charge Equalization via DC-DC Converter Energy Transfer

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Solution Overview

Problem

Existing charge balancing systems for electrochemical accumulator batteries in electric and hybrid transport applications face inefficiencies, particularly in energy transfer and consumption, leading to suboptimal battery charging and discharging due to high energy dissipation and temperature issues.

Innovation Solution

A charge balancing system comprising voltage generators, inductances, capacitors, diodes, and a control device that stores and transfers energy between accumulator stages, optimizing energy distribution without excessive energy loss, using a configuration that operates in discontinuous conduction mode to minimize energy wastage and maintain efficient battery charging.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If energy-dissipating balancing devices are used to equalize voltage across stages, then voltage uniformity is achieved, but energy consumption increases significantly and temperature rises

Engineering Contradiction:
Improvevoltage uniformityVSAvoidenergy consumption
Core Design Contradiction:
Stability of the object's compositionVSLoss of energy

Solution Approach 1:

A DC-DC converter is introduced as an intermediary device between the accumulator stages and the load. This converter actively manages energy distribution, transferring excess energy from fully charged stages to stages that are less charged, rather than dissipating it as heat. The converter acts as a mediator that enables controlled energy redistribution throughout the battery system.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The system dynamically changes operating parameters by adjusting the duty cycle of the DC-DC converter based on the state of charge of individual stages. By monitoring voltage levels and modifying the converter's switching parameters in real-time, the system optimizes energy transfer efficiency and prevents both overcharging and excessive energy dissipation.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If charging is stopped when the most charged stage reaches threshold voltage, then safety is ensured, but other stages remain undercharged reducing autonomy

Engineering Contradiction:
ImprovesafetyVSAvoidautonomy
Core Design Contradiction:
ReliabilityVSDuration of action of moving object

Solution Approach 1:

The DC-DC converter performs preliminary energy redistribution during the charging process, continuously balancing energy across all stages before any stage reaches the threshold voltage. This preliminary action ensures that when one stage reaches the threshold, all other stages are already close to full charge, maximizing autonomy without compromising safety.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system implements continuous feedback monitoring of voltage levels across all accumulator stages. Based on this feedback, the DC-DC converter dynamically adjusts its operation to maintain optimal charge distribution, ensuring that charging continues safely and efficiently until all stages are adequately charged.

Inventive Principle:
Principle #23Feedback

3Power

If multiple accumulators are placed in series to increase voltage, then system voltage requirements are met, but voltage differences between stages arise due to manufacturing and aging disparities

Engineering Contradiction:
Improvesystem voltageVSAvoidvoltage consistency
Core Design Contradiction:
PowerVSStability of the object's composition

Solution Approach 1:

The DC-DC converter serves as an intermediary that actively compensates for inherent differences between accumulator stages. By continuously monitoring and adjusting energy distribution, it counteracts voltage imbalances caused by manufacturing tolerances and aging effects, maintaining consistent voltage across all stages.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The system transitions from a static charging approach to a dynamic one, where the DC-DC converter continuously adapts its operation based on real-time voltage measurements. This dynamic adjustment allows the system to compensate for changing conditions and maintain voltage consistency throughout the battery pack's operational life.

Inventive Principle:
Principle #15Dynamics

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

The system ensures balanced charging and discharging of accumulator stages, reducing energy dissipation and maintaining battery health by optimizing energy transfer, thus enhancing the autonomy and reliability of electric and hybrid transport systems.

Implementation Method 1

at least one inductance, at least one first capacitor, the first end of which is connected to said positive pole of said at least one voltage generator

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

at least one first diode connected by its anode to the negative pole of said accumulator stage and by its cathode to the second end of said at least one first capacitor

Methodology Applied
Scientific EffectDiode rectification: Diode

Implementation Method 3

at least one first capacitor, the first end of which is connected to said positive pole of said at least one voltage generator

Methodology Applied
Scientific EffectCapacitance: Capacitance

Data Source

PatentEP2532068B1Charge equalization system for batteries
Publication Date: 2014.08.13 COMMISSARIAT A LENERGIE ATOMIQUE ET AUX ENERGIES ALTERNATIVES
  • EP2532068B1 patent drawingFigure 1~2
  • EP2532068B1 patent drawingFigure 3
  • EP2532068B1 patent drawingFigure 4

AI summary

The invention relates to an equalization system for batteries, comprising at least two accumulator stages (Eti) in series, each accumulator stage (Eti) comprising at least one accumulator (Aij). According to the invention, said system comprises: at least one voltage generator (7); an associated charging device (5) for each accumulator stage (Eti), powered by said at least one voltage generator (7) and comprising at least one inductance, at least one first and one second capacitor, at least two diodes, and at least one switch; and a control device (3) for controlling said at least one voltage generator (7), for closing said at least one switch of a charging device (5) associated with an accumulator stage (Eti) to be charged, so that said at least one inductance stores energy, and for transferring said energy to said associated accumulator stage (Eti).