Battery Load Balancing Device Using Resonant Energy Transfer

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing charge balancing devices for power batteries with electrochemical accumulators face inefficiencies, such as high energy consumption and long balancing times, particularly when dealing with significant imbalances between stages, and are costly due to the need for precise measurements and high component costs.

Innovation Solution

A load balancing device with a transformer and AC/DC converters that operates in step-level and constant-level modes, using a series resonant circuit and control circuit to optimize energy transfer between stages, reducing Joule effect losses and balancing time, while maintaining efficiency and cost-effectiveness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If energy dissipation balancing systems are used to make voltage uniform across stages, then voltage uniformity is improved, but energy consumption increases significantly

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

Solution Approach 1:

The patent introduces a DC-DC converter as an intermediary device between the battery stages and the load. This converter actively manages power distribution by measuring individual stage voltages and dynamically adjusting current allocation, thereby achieving voltage uniformity without the excessive energy dissipation of traditional resistor-based balancing systems.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The system dynamically changes operating parameters (current allocation, switching frequencies) based on real-time voltage measurements. The DC-DC converter adjusts its operating parameters to optimize power distribution across stages, transitioning from static to adaptive parameter control to minimize energy loss while maintaining voltage uniformity.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If traditional balancing devices are used to charge multiple stages, then all stages can be charged, but balancing time increases significantly

Engineering Contradiction:
Improvecomplete charging of all stagesVSAvoidbalancing time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent implements dynamic current allocation where the DC-DC converter continuously adjusts the current supplied to each stage based on its charge state. Instead of using fixed current values, the system dynamically modifies operating parameters to prioritize stages that need charging, thereby reducing overall balancing time while ensuring all stages reach full charge.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system employs periodic measurement and adjustment cycles, continuously monitoring stage voltages and recalibrating current distribution at optimized intervals. This periodic control approach allows the system to respond to changing battery states efficiently, reducing the time required to achieve complete balancing across all stages.

Inventive Principle:
Principle #19Periodic action

3Measurement precision

If precise measurement and high component specifications are used in balancing devices, then measurement accuracy is improved, but device cost increases

Engineering Contradiction:
Improvevoltage measurement accuracyVSAvoidcomponent cost
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The DC-DC converter is designed as a multi-functional device that performs voltage regulation, current distribution, measurement, and control functions in a single integrated system. By combining multiple functions into one device, the patent reduces the need for separate expensive components while maintaining high measurement precision through the converter's integrated sensing and control capabilities.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 solution significantly reduces balancing times and energy consumption, optimizing energy transfer and maintaining high efficiency, even at low power levels, thereby enhancing the overall performance and reducing costs associated with balancing power batteries.

Implementation Method 1

a transformer (310)

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

a series resonant circuit (340)

Methodology Applied
Scientific EffectResonance: Resonance

Data Source

PatentEP3075058B1Device for balancing a power battery element load
Publication Date: 2020.03.11 RENAULT SA
  • EP3075058B1 patent drawingFigure 1~3
  • EP3075058B1 patent drawingFigure 4~5
  • EP3075058B1 patent drawingFigure 6~7

AI summary

The invention relates to a device (3) for balancing the load of a storage device including a plurality of elements connected in series. Said device includes: a DC/AC converter (320) including an inverter and a series resonant circuit (340) connected to the output of the inverter; a plurality of AC/DC converters (301, 302, 303), each comprising an input and an output that is connected to one of said respective storage elements and selectively supplies power to the output thereof; a transformer (310), the main winding (311) of which is connected to the series resonant circuit (340) and the secondary winding (312) of which has outputs connected to an input of a respective AC/DC converter; and a control circuit (5) configured to control the DC/AC converter (320) at the current source when the number of outputs supplied with power is no higher than a threshold and moreover configured to control the DC/AC converter (320) at a constant power when the number of outputs supplied with power is greater than said threshold.