Battery Internal Resistance Authentication via Temperature Compensation

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Solution Overview

Problem

Existing electric storage devices, such as lithium ion secondary batteries, face challenges in authenticating regularity and detecting battery cell exchanges due to temperature conditions not being considered, leading to safety issues and increased costs.

Innovation Solution

An electric storage device that measures temperature and calculates internal resistance based on voltage, current, and temperature, enabling accurate determination of battery cell authenticity and detecting potential exchanges.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If IC authentication is mounted on both electric storage device and electronic device, then authentication reliability is improved, but device complexity and cost increase

Engineering Contradiction:
Improveauthentication reliabilityVSAvoiddevice complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent extracts the authentication function from the electronic device side and concentrates it entirely on the electric storage device side. By removing the need for IC authentication in the electronic device, the system achieves reliable authentication while reducing overall device complexity and cost.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent introduces terminal voltage and current as intermediary parameters for authentication. Instead of using IC communication between two devices, the system uses electrical parameters (voltage and current measurements) as mediators to determine authenticity, simplifying the authentication mechanism.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Difficulty of detecting and measuring

If internal resistance measurement is used to detect battery exchange, then detection capability is improved, but temperature conditions are not considered leading to measurement precision degradation

Engineering Contradiction:
Improvebattery exchange detection capabilityVSAvoidinternal resistance measurement precision
Core Design Contradiction:
Difficulty of detecting and measuringVSMeasurement precision

Solution Approach 1:

The patent changes the measurement parameters from direct internal resistance measurement to terminal voltage and current measurements. By measuring terminal voltage during charging/discharging and calculating current, then deriving internal resistance from these parameters, the system achieves temperature-compensated measurement that improves precision while maintaining detection capability.

Inventive Principle:
Principle #35Parameter changes

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 allows for accurate authentication and detection of battery cell exchanges while considering temperature conditions, enhancing safety and reducing costs by eliminating the need for redundant IC authentication systems.

Implementation Method 1

a controller that calculates internal resistance after correction performed by correcting internal resistance based on a temperature of the electric storage element measured by the temperature measurement unit

Methodology Applied
Scientific EffectElectrical Resistance: Electrical Resistance

Implementation Method 2

a temperature measurement unit that measures a temperature of the electric storage element; and a controller that calculates internal resistance after correction performed by correcting internal resistance based on a temperature of the electric storage element

Methodology Applied
Scientific EffectTemperature measurement:

Data Source

PatentEP2796312B1Electrical storage device, electronic instrument, power system, and electric vehicle
Publication Date: 2020.03.04 MURATA MFG CO LTD
  • EP2796312B1 patent drawingFigure 1
  • EP2796312B1 patent drawingFigure 2
  • EP2796312B1 patent drawingFigure 3

AI summary

An electric storage device includes an electric storage unit that includes one or a plurality of electric storage elements, a measurement unit that measures voltage, a current, and a temperature of the electric storage element, and a calculation unit that calculates internal resistance of the electric storage element based on the voltage, the current, and the temperature measured by the measurement unit. When a determination unit detects discontinuity of temporal variation of the calculated internal resistance, it is determined that the electric storage element has been exchanged. Since the electric storage element such as a lithium ion secondary battery has such a characteristic that the internal resistance increases as the number of use is increased, the exchange of batteries can be detected from the change in the internal resistance.