Charge Balancing System for Batteries Using Auxiliary Network

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Solution Overview

Problem

Existing battery charge balancing systems for electric and hybrid transport applications are inefficient, leading to energy wastage and reduced battery lifespan due to high energy dissipation and temperature issues, as they either consume excessive energy or require lengthy balancing times with low efficiency.

Innovation Solution

A load balancing system utilizing a plurality of converters for bidirectional energy transfer between a power battery and an auxiliary network, allowing for efficient balancing by switching on converters associated with the most charged modules to discharge excess energy into the network, thereby optimizing charge distribution and reducing energy losses.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If energy dissipation balancing systems are used to equalize voltage across stages, then charge balancing is achieved, but excessive energy is consumed and dissipated as heat

Engineering Contradiction:
Improvecharge balancingVSAvoidenergy dissipation
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The patent introduces an auxiliary battery as an intermediary energy storage device that facilitates bidirectional energy transfer between battery stages. Instead of directly dissipating energy from charged stages, the system transfers excess energy to the auxiliary battery, which then redistributes it to less charged stages, thereby achieving balancing while minimizing energy loss and avoiding heat generation.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The system dynamically changes the operating parameters of converters based on the charge states of different battery stages. By adjusting converter operation modes and switching between charging/discharging states, the system optimizes energy transfer efficiency and minimizes losses during the balancing process.

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 system performs preliminary balancing actions during the charging process by continuously monitoring stage voltages and actively transferring energy between stages. This preliminary action ensures that all stages reach optimal charge levels before the charging cycle concludes, preventing the scenario where charging must be stopped early due to a single stage reaching threshold voltage.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system implements continuous feedback monitoring of voltage levels across all battery stages and dynamically adjusts energy transfer operations. This feedback mechanism allows the system to maintain safety thresholds while optimizing the charge state of all stages, thereby maximizing autonomy without compromising safety.

Inventive Principle:
Principle #23Feedback

3Stability of the object's composition

If multiple accumulators are discharged to balance the last accumulator, then charge uniformity is achieved, but the process consumes more energy than necessary

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

Solution Approach 1:

The auxiliary battery serves as an intermediary that decouples the energy transfer process between charged and uncharged stages. Instead of directly discharging multiple accumulators to balance the last one, the system transfers excess energy to the auxiliary battery first, then redistributes it as needed, thereby minimizing unnecessary energy consumption and improving overall efficiency.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 approach enables efficient balancing of battery stages without excessive energy consumption, prolongs battery lifespan, and ensures reliable power supply by eliminating the need for an auxiliary battery, while maintaining system availability and safety.

Implementation Method 1

A load balancing system utilizes a plurality of converters for bidirectional energy transfer between a power battery and an auxiliary network

Methodology Applied
Scientific EffectElectrical energy transfer: Conduction (electrical)

Data Source

PatentEP2684274B1Charge balancing system for batteries
Publication Date: 2022.05.04 COMMISSARIAT A LENERGIE ATOMIQUE ET AUX ENERGIES ALTERNATIVES
  • EP2684274B1 patent drawingFigure 1~2
  • EP2684274B1 patent drawingFigure 3~5b
  • EP2684274B1 patent drawingFigure 6~7a

AI summary

The present invention relates to a charge balancing system for a power battery (101) comprising at least two accumulator stages (111) connected in series, an accumulator stage (111) comprising at least one accumulator (9). Said system comprises: a plurality of isolated converters (123) connected in parallel, the converters being respectively connected, on the one hand, to a preset number of associated accumulator stages (111) and, on the other hand, to a low-voltage network for supplying power to auxiliary electrical systems of an automotive vehicle; and a unit for controlling said converters (123), the unit being configured to control at least one converter (123) so as to charge the preset number of associated accumulator stages to a similar charge level, and so as to control the supply of power from the power battery (1) to said low-voltage network via converters (107), in order to supply said auxiliary systems with power.