Battery Charge Time Calculation Correction for Accuracy

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Solution Overview

Problem

Existing charge control systems inaccurately calculate remaining charge time, leading to increased displayed time despite ongoing charging, when charge current decreases, causing user discomfort.

Innovation Solution

A charge control device and method that subtracts time based on the battery's charge state from the remaining charge time calculated using maps, ensuring the displayed time decreases with increasing SOC during charging.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the remaining charge time is calculated using maps showing the relationship between battery capacity and terminal voltage, then the remaining charge time can be displayed to users, but when the charge current decreases during charging, the calculated remaining charge time becomes longer despite ongoing charging

Engineering Contradiction:
Improveremaining charge time calculation accuracyVSAvoidcharging progress indication reliability
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent implements feedback by continuously monitoring the charge current during the charging process and using this information to adjust the remaining charge time calculation. The charge control device acquires actual charge current values and compares them with the maps to determine correction amounts, thereby dynamically adjusting the displayed remaining charge time to reflect actual charging progress accurately.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent changes the calculation parameters by introducing a correction amount that adjusts the remaining charge time based on the actual charge current. Instead of relying solely on the static map data, the system modifies the remaining charge time calculation by adding or subtracting correction amounts derived from the difference between actual and expected charge current values at different SOC levels.

Inventive Principle:
Principle #35Parameter changes

2Ease of operation

If maps are used to calculate remaining charge time based on terminal voltage and battery capacity, then charging information can be provided to users, but the calculation becomes inaccurate when charge current varies during the charging process

Engineering Contradiction:
Improvecharging information displayVSAvoidremaining charge time accuracy
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The system uses feedback by continuously measuring the actual charge current and using this information to correct the remaining charge time calculation. The charge control device acquires charge current values during charging, compares them with map values, and adjusts the displayed time accordingly to maintain accuracy despite current variations.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent replaces the purely static map-based calculation method with a dynamic calculation approach that incorporates real-time electrical parameter measurements. By substituting the static lookup method with a dynamic calculation that uses actual charge current data, the system achieves more accurate remaining charge time estimation under varying charging conditions.

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

Data Source

PatentEP2899843B1Charging control device and charging time calculation method
Publication Date: 2018.07.04 NISSAN MOTOR CO LTD
  • EP2899843B1 patent drawingFigure 1
  • EP2899843B1 patent drawingFigure 2
  • EP2899843B1 patent drawingFigure 3

AI summary

A charge control device that charges a battery (20) using power output from a charger (10), wherein detecting means, charge state (SOC) calculation means, chargeable power calculation means, charge power calculation means, and charge time calculation means are provided. The detecting means detects the voltage and current of the battery (20). The charge state (SOC) calculation means calculates the SOC of the battery (20) using the detected values of detecting means. The chargeable power calculation means uses the detected values to calculate the power with which to charge the battery (20). The charge power calculation means calculates the charge power to be supplied to the battery (20) from the charger. The charge time calculation means refers to a map indicative of a relationship of the charge time of the battery (20) with respect to the charge state and charge power when the chargeable power for charging is greater than the outputtable power, which represents the power that is available to be outputted from the charger, and calculates, on the basis of the charge state calculated by the charge state calculation means and the charge power calculated by the charge power calculation means, the remaining charge time for the battery until the charge state of the battery (20) reaches a predetermined charge state. When the chargeable power for charging is less than the outputtable power, the charge time calculation means calculates the remaining charge time by subtracting the time according to the charge state from the remaining charge time calculated using the map.