Capacitor-Coupled Battery Balancing Circuit for Low-Loss Operation

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Solution Overview

Problem

Existing battery balancing systems face inefficiencies in low-power applications due to inherent losses in balancing circuit componentry, particularly in smaller battery cells, and are affected by aging and environmental influences that alter the resonant frequency, leading to inaccurate voltage monitoring and potential system damage.

Innovation Solution

A low-loss battery balancing system that synchronizes charge balancing circuits with a system clock to minimize losses and adapt to changing resonant frequencies, using capacitor-coupled circuits instead of transformer-coupled ones, and incorporates a phase-locked loop to maintain optimal operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If transformer-coupled balancing circuits are used, then charge balancing can be achieved, but inherent losses (core loss and IR loss) substantially impact system performance in low-power applications

Engineering Contradiction:
Improvebalancing circuit lossesVSAvoidsystem performance
Core Design Contradiction:
Loss of energyVSReliability

Solution Approach 1:

The patent extracts and removes the transformer component from the balancing circuit, replacing it with a capacitor-coupled circuit. This elimination of the transformer eliminates the source of core loss and magnetizing current IR loss, directly resolving the technical contradiction by removing the harmful element rather than attempting to mitigate its effects.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent substitutes the electromagnetic transformation mechanism (transformer) with a capacitive coupling mechanism. This replacement changes the fundamental operating principle from electromagnetic induction to capacitive energy transfer, thereby eliminating the inherent losses associated with transformer operation while maintaining the charge balancing function.

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

2Adaptability or versatility

If circuits are driven at a constant drive frequency, then the circuit operates as manufactured, but the resonant frequency evolves due to aging and environmental factors causing performance decline

Engineering Contradiction:
Improveresonant frequency adaptationVSAvoidcircuit response time
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent implements a dynamic frequency adjustment mechanism where the drive frequency is continuously adapted to match the evolving resonant frequency of the circuit. Instead of using a fixed constant frequency, the system dynamically tracks and adjusts to the changing resonant conditions caused by aging and environmental factors, maintaining optimal performance throughout the circuit's operational life.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent employs a feedback mechanism that monitors the actual resonant frequency of the circuit and uses this information to adjust the drive frequency accordingly. This closed-loop control ensures that the circuit operates at its optimal resonant frequency despite changes due to aging, temperature, or other environmental influences, thereby maintaining reliable performance.

Inventive Principle:
Principle #23Feedback

3Power

If transformers are used in balancing circuits, then charge transfer is enabled, but core loss and magnetizing current create substantial negative impact in smaller battery cells

Engineering Contradiction:
Improvecharge transfer capabilityVSAvoidcore loss and IR loss
Core Design Contradiction:
PowerVSLoss of energy

Solution Approach 1:

The patent removes the transformer component entirely from the balancing circuit, replacing it with a capacitor-coupled architecture. This extraction eliminates the sources of core loss and magnetizing current, directly addressing the energy loss problem while preserving the essential charge transfer functionality through an alternative mechanism.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent changes the fundamental operating parameters of the balancing circuit by transitioning from electromagnetic transformation to capacitive coupling. This parameter change alters the energy transfer mechanism to one that does not suffer from core loss or magnetizing current, thereby enabling efficient operation in low-power applications with smaller battery cells.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP2243206B1Low-power battery system
Publication Date: 2020.10.21 COBHAM LONG ISLAND INC
  • EP2243206B1 patent drawingFigure 1
  • EP2243206B1 patent drawingFigure 2
  • EP2243206B1 patent drawingFigure 3A

AI summary

A system for balancing the charge level of a plurality of electrically coupled battery units. The system configuration may utilize an architecture and/or methodology that is more appropriate for lower power applications. In particular, the present invention, in accordance with at least one embodiment, may provide a battery balancing system that implements low loss charge balancing circuits in a compact configuration suitable for a multitude of applications, such as smaller cell battery balancing. The charge balancing circuits may be incorporated within each battery unit.