Battery Controller Current Integration for Voltage Detector Malfunction

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Solution Overview

Problem

Existing battery management systems face challenges in accurately calculating the state of charge (SOC) when a voltage detector malfunctions, leading to potential overcharge or over-discharge, which can damage the battery and result in unexpected vehicle unavailability.

Innovation Solution

A battery controller that integrates charge and discharge currents to calculate an actual charge current, prohibits charging/discharging when the actual charge current exceeds a predetermined value, and sets this value based on the SOC and battery temperature, while also notifying the user of malfunctions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the battery controller prohibits charging/discharging when voltage detector malfunction is detected, then battery protection from overcharge is improved, but vehicle mobility and user convenience deteriorate

Engineering Contradiction:
Improvebattery protectionVSAvoidvehicle mobility
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent introduces current integration as an intermediary mechanism to bridge the gap between voltage detector malfunction and battery protection. Instead of directly prohibiting charging/discharging, the system uses current integration to calculate actual charge current amount, which then triggers prohibition only when exceeding predetermined values, thus maintaining mobility while protecting the battery

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The system changes the control parameter from voltage-based (which becomes unreliable during malfunction) to current-based control. By integrating charge and discharge currents and comparing the actual charge current amount against predetermined values, the system maintains reliable battery protection without requiring accurate voltage detection

Inventive Principle:
Principle #35Parameter changes

2Productivity

If the battery controller allows continuous charging/discharging when voltage detector malfunction occurs, then vehicle mobility is maintained, but battery damage from overcharge increases

Engineering Contradiction:
Improvevehicle mobilityVSAvoidbattery protection
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The system implements feedback control by continuously integrating charge and discharge currents and comparing the actual charge current amount against predetermined thresholds. This feedback mechanism enables the controller to dynamically adjust charging/discharging permissions, maintaining mobility when safe while preventing overcharge when limits are approached

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

Current integration serves as an intermediary that translates raw current measurements into meaningful charge state information. This intermediary calculation layer enables reliable battery management during voltage detector malfunction by providing a alternative basis for control decisions

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If the battery controller immediately prohibits battery use when voltage detector malfunction is detected, then battery protection is maximized, but user convenience and operational continuity deteriorate

Engineering Contradiction:
Improvebattery protectionVSAvoiduser convenience
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

Instead of immediately and completely prohibiting battery use, the system applies partial action by allowing charging/discharging to continue when the actual charge current amount remains below predetermined values. Prohibition is applied only when necessary to prevent overcharge, thus maintaining ease of operation while ensuring protection

Inventive Principle:
Principle #16Partial or excessive action

Data Source

PatentEP3154150B1Battery controller
Publication Date: 2019.07.24 MITSUBISHI MOTORS CORP
  • EP3154150B1 patent drawingFigure 1
  • EP3154150B1 patent drawingFigure 2
  • EP3154150B1 patent drawingFigure 3

AI summary

A battery controller that controls a battery for supplying power to a load apparatus, includes a current detection unit (22), that detects a discharge current and a charge current of the battery (12), a malfunction detection unit (106) that detects malfunction of a voltage detector (16) for detecting a voltage of the battery, and a contactor control unit that is provided on a power supply line through which the discharge current and the charge current flow to open/close a contactor. The contactor control unit (110) integrates the charge and discharge current when the malfunction of the voltage detector is detected, calculates an actual charge current amount obtained by subtracting an integrated value of the discharge current from an integrated value of the charge current, and prohibits charging/discharging of the battery by controlling the contactor when the actual charge current amount is equal to or more than a predetermined value.