Backup Capacitor Control for Ignition-Off Power Discharge

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Solution Overview

Problem

Existing backup power supplies, such as electric double layer capacitors and lithium ion capacitors, deteriorate when charges are accumulated for long periods or when fully charged, leading to inefficient discharge and waste of stored energy.

Innovation Solution

A backup power-supply device that includes an electric double layer capacitor or lithium ion capacitor, a charging circuit, a discharging circuit, switches, and a control unit to manage charging and discharging, ensuring efficient use of stored energy by preventing deterioration and optimizing power delivery to essential electronic devices during main power supply failures.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the capacitor is discharged by discharge resistance when ignition is turned off, then the capacitor is prevented from deteriorating, but electric charges are discharged in a waste manner

Engineering Contradiction:
Improvecapacitor durabilityVSAvoidenergy waste
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The capacitor serves dual purposes: it powers essential electronic devices during backup and simultaneously discharges itself through these devices, eliminating the need for separate discharge resistance and preventing waste of stored energy

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The capacitor's stored energy is utilized for multiple functions: providing backup power to essential devices and serving as a discharge path through the same devices, thereby achieving both power supply and self-discharge purposes through a single mechanism

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Reliability

If the capacitor remains fully charged for long periods, then backup power is ready, but the capacitor deteriorates

Engineering Contradiction:
Improvebackup power readinessVSAvoidstorage time
Core Design Contradiction:
ReliabilityVSDuration of action of stationary object

Solution Approach 1:

The control unit periodically monitors capacitor charge levels and manages discharge cycles, allowing the capacitor to remain charged for extended periods while periodically utilizing its energy to power devices, thereby preventing long-term full charge deterioration

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The control unit monitors the capacitor's charge state and automatically manages discharge through electronic devices when appropriate, creating a feedback mechanism that prevents prolonged full charge conditions while ensuring backup power readiness

Inventive Principle:
Principle #23Feedback

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

Effectively utilizes stored energy in capacitors to power critical devices after the main power supply is cut off, preventing deterioration and ensuring continued operation of essential systems until the capacitor's energy is depleted.

Implementation Method 1

A power supply employing an electric double layer capacitor or a lithium ion capacitor has been proposed as a backup power supply

Methodology Applied
Scientific EffectElectric double layer capacitor: Capacitance

Implementation Method 2

A power supply employing an electric double layer capacitor or a lithium ion capacitor has been proposed as a backup power supply

Methodology Applied
Scientific EffectLithium ion capacitor: Battery (electricity)

Implementation Method 3

it is considered to discharge the electric double layer capacitor or the lithium ion capacitor by discharge resistance

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Data Source

PatentEP4125179B1Backup power-supply device
Publication Date: 2023.12.20 YAZAKI CORP
  • EP4125179B1 patent drawingFigure 1
  • EP4125179B1 patent drawingFigure 2
  • EP4125179B1 patent drawingFigure 3

AI summary

A backup power-supply device (3) including a control unit (35) is provided. In a case where a main power supply is normal when an ignition is turned on, the control unit (35) controls to turn on or off a charging circuit (32) to charge a capacitor (31) from the main power supply (2) so that a voltage of the capacitor (31) becomes constant at a target voltage and turns off the discharging circuit (33) to stop discharging from the capacitor (31) to a first electronic device (4). In a case where an abnormality occurs in the main power supply (2) when the ignition is turned on, the control unit (35) turns off the charging circuit (32) to stop charging from the main power supply (2) to the capacitor (31) and turns on the discharging circuit (33) to perform discharging from the capacitor to the first electronic device (4). A first switch (S1) is provided between a second electronic device (5) and the capacitor (31). The control unit (35) turns on the discharging circuit (33) and the first switch (S1) and turns off the charging circuit (32) after the ignition is turned off to perform discharging from the capacitor (31) to the second electronic device (5).