Communication Circuit Level Shift for Battery Module Stability

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Solution Overview

Problem

Existing communication systems in assembled battery modules face challenges with stable communication due to large potential differences between monitoring circuits, leading to power wastage and instability, especially when connected to inverters or converters, which generate noise.

Innovation Solution

The implementation of a communication circuit with a level shift circuit and direct-current converter, allowing differential communication between monitoring circuits with different reference potentials, eliminating the need for high-power isolation circuits and reducing noise interference.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If isolation transformer or optical isolator is used to isolate reference potential, then communication stability is improved, but power consumption increases and power storing performance decreases

Engineering Contradiction:
Improvecommunication stabilityVSAvoidpower consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent introduces a level shift circuit as an intermediary component between monitoring circuits with different reference potentials. This circuit mediates the potential difference through capacitor coupling, enabling communication without requiring high-power isolation transformers or optical isolators, thus resolving the contradiction between communication stability and power consumption

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The invention changes the communication approach from isolated state (requiring large current) to differential mode with level shifting. By altering the reference potential parameters dynamically and using capacitor coupling, the system achieves stable communication with minimal power consumption, directly addressing the energy efficiency problem

Inventive Principle:
Principle #35Parameter changes

2Adaptability or versatility

If monitoring circuits are connected in series through communication line, then communication between assembled batteries is enabled, but large potential difference causes communication instability

Engineering Contradiction:
Improvecommunication capabilityVSAvoidcommunication stability
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent applies equipotentiality principle by using level shift circuits to equalize reference potentials between communicating monitoring circuits. The capacitor coupling in the differential communication interface creates an equipotential reference point, eliminating the large potential difference that causes communication instability in series-connected assembled batteries

Inventive Principle:
Principle #12Equipotentiality

Solution Approach 2:

The invention creates a copied reference potential system where each monitoring circuit maintains its own reference potential but communicates through a shared differential interface. The level shift circuit copies and adapts reference potentials between circuits, enabling stable communication across different potential levels without direct connection

Inventive Principle:
Principle #26Copying

3Reliability

If large current is used for isolated state communication, then communication under large potential difference is achieved, but power wastage occurs and battery performance decreases

Engineering Contradiction:
Improvecommunication reliabilityVSAvoidpower wastage
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The patent replaces the mechanical/electrical isolation system (isolation transformers requiring large current) with an electronic field-based system using capacitor coupling and differential signaling. This substitution eliminates the need for large currents while maintaining communication reliability under large potential differences, directly reducing power wastage

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

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

Enables stable and efficient communication across assembled battery modules with significant potential differences without excessive power consumption, maintaining battery performance and stability even in noisy environments.

Implementation Method 1

a first communication line and a second communication line which are coupled by a capacitor

Methodology Applied
Scientific EffectCapacitance: Capacitance

Data Source

PatentEP2319726B1Communication circuit, assembled battery unit, and vehicle
Publication Date: 2019.01.02 KK TOSHIBA
  • EP2319726B1 patent drawingFigure 1
  • EP2319726B1 patent drawingFigure 2
  • EP2319726B1 patent drawingFigure 3~4B

AI summary

According to one embodiment, a communication circuit includes a direct-current converter circuit (23a) configured to generate a second power supply potential different from a second reference potential by a predetermined potential, from a first power supply potential, a first receiving circuit (25a) configured to receive a binary communication signal, whose one level is at a first reference potential, through a first signal input terminal, by a differential transmission method, a first level shift circuit (241a) configured to convert the communication signal received by the first receiving circuit into a binary communication signal, whose one level is at the second reference potential, and the other level is at the second power supply potential, and a first transmission circuit (26a) configured to output the binary communication signal converted by the first level shift circuit, through a first signal output terminal, by a differential transmission method.