Semi-Passive RFID Battery Cell Controller Wireless Monitoring

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Solution Overview

Problem

The existing inductive-coupled RFID systems for battery state monitoring have a short communication distance, limiting flexibility and configuration in battery systems for hybrid electric and electric vehicles.

Innovation Solution

Implementing a semi-passive RFID system with wireless communication using electric power from battery cells to extend communication distance, allowing for reliable state monitoring across several meters, and using low-power wireless communication between the battery and host controllers to eliminate wiring and reduce costs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If inductive-coupled RFID is used for battery state monitoring, then wireless communication is achieved, but communication distance is limited to several centimeters to several tens of centimeters

Engineering Contradiction:
Improvewireless communication capabilityVSAvoidcommunication distance
Core Design Contradiction:
Use of energy by moving objectVSLength of stationary object

Solution Approach 1:

The patent changes the power supply mode of the RFID tag from passive to semi-passive by introducing an independent power source (battery). This parameter change enables the tag to have sufficient power for both wireless communication and impedance modulation, extending communication distance from centimeters to meters while maintaining wireless operation capability.

Inventive Principle:
Principle #35Parameter changes

2Use of energy by moving object

If inductive-coupled RFID is used for battery state monitoring, then wireless communication is achieved, but layout flexibility and device configuration flexibility are reduced

Engineering Contradiction:
Improvewireless communication capabilityVSAvoidlayout flexibility
Core Design Contradiction:
Use of energy by moving objectVSAdaptability or versatility

Solution Approach 1:

By changing the power supply parameter from passive to semi-passive mode, the RFID tag gains sufficient energy to support extended communication ranges. This enables flexible layout configurations where battery modules can be positioned at various distances from the control device without being constrained by short communication ranges, thereby improving adaptability in system design and installation.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If wiring is used for battery state monitoring, then reliable communication is achieved, but cost for wiring and insulation increases

Engineering Contradiction:
Improvecommunication reliabilityVSAvoidwiring cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent replaces the mechanical wiring system with a wireless communication system using semi-passive RFID technology. The battery-powered RFID tags transmit battery state information wirelessly through impedance modulation, eliminating the need for physical wiring and insulation materials, thereby reducing manufacturing costs while maintaining communication reliability through the robust RFID protocol.

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

The solution extends communication distance in battery systems, enabling reliable state monitoring and reducing power consumption while eliminating the need for wiring between components, thereby enhancing flexibility and reducing costs.

Implementation Method 1

an inductive-coupled RFID installed in a module for measuring voltage values of the battery cells transmits the voltage values of the battery cells to a reading device in a form of wireless signal

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP2980912B1Battery system
Publication Date: 2018.03.14 HITACHI AUTOMOTIVE SYST LTD
  • EP2980912B1 patent drawingFigure 1
  • EP2980912B1 patent drawingFigure 2
  • EP2980912B1 patent drawingFigure 3

AI summary

Communication distance can be extended in a battery system that transmits states of the battery cells by wireless communication. Each of cell controllers 100 wirelessly transmits measurement result of states of battery cells in cell groups 10 to a battery controller 200, by using an electric power supplied from the battery cells in the cell groups 10. The battery controller 200 continuously transmits unmodulated carrier wave to each of the cell controllers 100. Each of the cell controllers 100 changes an impedance for the unmodulated carrier wave transmitted from the battery controller 200 at a predetermined timing in dependence on the measurement result of the states of the battery cells in the cell groups 10. Due to this, the measurement result of the states of the battery cells in the cell groups 10 is wirelessly transmitted to the battery controller 200.