Parallel Battery Balancing via Current Flow Control Mechanism

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Solution Overview

Problem

The parallel connection of battery cells with different technologies or chemistries often results in voltage imbalances, preventing successful use and limiting the benefits of combined power and energy capabilities.

Innovation Solution

A system with a current flow control mechanism that adjusts current flow between battery interfaces to match voltage profiles, using a bidirectional buck/boost converter and switch mode power supply to maintain optimized charge levels and compatibility between different voltage curves, enabling the parallel use of cells with varying characteristics.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If multiple battery cells with different technologies or chemistries are connected in parallel, then the combined power and energy capabilities are improved, but voltage imbalances occur that prevent successful use

Engineering Contradiction:
Improvecombined power capabilityVSAvoidvoltage balance
Core Design Contradiction:
PowerVSReliability

Solution Approach 1:

The patent introduces an intermediary voltage matching circuit between battery cells of different technologies. This circuit includes switching elements and control logic that actively regulate voltage distribution, allowing cells with different voltage profiles (e.g., Li-ion and NiMH) to be connected in parallel without causing imbalance. The intermediary circuit acts as a buffer that reconciles the conflicting voltage characteristics of different cell types.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The system dynamically adjusts the connection state of battery cells through controlled switching. The switching elements change their state based on real-time voltage monitoring and control algorithms, enabling the system to adapt to the different discharge and charge characteristics of various cell technologies. This dynamic control allows the system to optimize power delivery while maintaining voltage balance across heterogeneous cells.

Inventive Principle:
Principle #15Dynamics

2Adaptability or versatility

If battery cells with different voltage profiles are connected in parallel, then versatility in battery assembly configuration is improved, but compatibility issues arise due to voltage mismatches

Engineering Contradiction:
Improvebattery assembly configurationVSAvoidvoltage compatibility
Core Design Contradiction:
Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The voltage matching circuit is designed as a universal solution that can handle multiple battery cell types and configurations. The control system recognizes different cell chemistries and automatically applies appropriate voltage balancing strategies, making the system compatible with various battery technologies (Li-ion, Li-polymer, NiMH, etc.) without requiring cell-specific design modifications.

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

Solution Approach 2:

The system changes operating parameters (voltage, current) dynamically based on the specific battery cell configuration. The control circuit monitors cell voltages and adjusts switching patterns to accommodate different voltage profiles, discharge rates, and charge acceptance characteristics of various cell types, thereby achieving compatibility across diverse battery configurations.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If current flow is controlled to match voltage profiles, then charge level optimization is improved, but system complexity increases due to additional control mechanisms

Engineering Contradiction:
Improvecharge level optimizationVSAvoidcontrol mechanism complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The system implements feedback control by continuously monitoring battery cell voltages and adjusting current distribution accordingly. Voltage sensors provide real-time data to the control logic, which then modifies switching element states to maintain optimal charge levels. This closed-loop feedback ensures reliable charge management while keeping the control algorithm relatively simple and computationally efficient.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The control system is designed to autonomously manage voltage balancing without requiring external intervention or complex processing. The switching elements and control logic work together in a self-regulating manner, where the system automatically detects voltage imbalances and corrects them through appropriate switching actions, reducing the need for complex external control mechanisms.

Inventive Principle:
Principle #25Self-service

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 allows for the simultaneous discharge and charge of cells with different characteristics, providing a 'hot swap' feature that enables battery replacement without powering down devices, while maintaining optimized charge levels and voltage compatibility, thus enhancing the performance and flexibility of battery assemblies.

Implementation Method 1

using a bidirectional buck/boost converter and switch mode power supply to maintain optimized charge levels and compatibility between different voltage curves

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

energy storage between the first battery interface and the second battery interface

Methodology Applied
Scientific EffectCapacitance: Capacitance

Data Source

PatentEP2747238B1Balancing of battery cells connected in parallel
Publication Date: 2019.11.13 NOKIA TECHNOLOGIES OY
  • EP2747238B1 patent drawingFigure 1
  • EP2747238B1 patent drawingFigure 2
  • EP2747238B1 patent drawingFigure 3

AI summary

Systems and techniques for parallel battery balancing are described. A battery assembly comprises a first battery interface and a second battery interface; the first battery interface may connect to a first battery exhibiting a first voltage profile and the second battery interface may connect to a second battery exhibiting a second voltage profile. The battery assembly further comprises a current flow control mechanism to direct current flow to, from, and between the first battery and the second battery, with current directed to each battery being adapted so as to be compatible with the voltage profile of the battery.