Electronic Door Latch Backup Power for Long-Term Parking

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Solution Overview

Problem

Existing electronically controlled door latches in vehicles face challenges in providing energy for long-term parking situations beyond a week and fail to open doors without a main or backup power source, especially after accidents or crashes.

Innovation Solution

An electronically controlled door latch arrangement with an unrechargeable auxiliary battery and a supercapacitor group that is charged by the main power source during normal operation, and by the auxiliary battery during power loss, actuated by an electric motor using PWM control.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Duration of action of moving object

If an electronically controlled door latch uses only a main power source and a backup supercapacitor, then the system is simple and reliable for short-term backup, but it cannot provide energy for long-term parking situations beyond a week

Engineering Contradiction:
Improvebackup energy durationVSAvoidpower supply system complexity
Core Design Contradiction:
Duration of action of moving objectVSDevice complexity

Solution Approach 1:

The power supply system is segmented into three distinct components: main power source for normal operation, supercapacitor for short-term backup (high power delivery), and auxiliary battery for long-term backup (energy storage). Each component has a specific function and operates in different scenarios, allowing the system to achieve extended backup duration without excessive complexity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent combines multiple energy storage technologies (supercapacitor and auxiliary battery) into a hybrid power supply system. The supercapacitor handles high-current demands for motor actuation, while the auxiliary battery provides sustained energy for long-term parking, creating a complementary system that leverages the strengths of both technologies.

Inventive Principle:
Principle #5Merging (Combining)

2Duration of action of moving object

If the door latch system includes an auxiliary battery and supercapacitor group, then long-term parking energy needs are met, but the device complexity increases

Engineering Contradiction:
Improvebackup energy durationVSAvoidpower supply system complexity
Core Design Contradiction:
Duration of action of moving objectVSDevice complexity

Solution Approach 1:

The supercapacitor group is pre-charged from the main power source during normal operation, and the auxiliary battery is pre-charged from either the main power source or the supercapacitor. This preliminary charging ensures that energy is available immediately when needed, eliminating the need for complex real-time power management during emergency situations.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The control unit acts as an intermediary that intelligently manages power flow between the main power source, auxiliary battery, and supercapacitor group. It determines when to charge which component and when to discharge, simplifying the overall system architecture by centralizing control logic rather than requiring complex hardware interconnections.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Device complexity

If no mechanical bowden cable or lever is available for the electronically controlled door latch, then the door cannot be opened without energy, but this provides a more compact design

Engineering Contradiction:
Improvemechanical componentsVSAvoiddoor opening capability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The system uses an electric motor to actuate the door latch, eliminating the need for mechanical bowden cables or levers. The motor is controlled by a control unit that can operate from multiple power sources, allowing the system to self-manage door opening without external mechanical assistance, even in power-loss scenarios.

Inventive Principle:
Principle #25Self-service

4Reliability

If the supercapacitor group is charged by the auxiliary battery during power loss, then energy availability is improved, but power management complexity increases

Engineering Contradiction:
Improveenergy availabilityVSAvoidpower management system
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The control unit continuously monitors the state of charge of the supercapacitor group and the auxiliary battery, and automatically activates charging operations when voltage thresholds are met. This feedback-based control ensures optimal power management without requiring complex manual intervention or overly sophisticated power management circuitry.

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

Ensures reliable door operation during power failures or long-term parking by maintaining energy for the electric motor, allowing door opening without mechanical assistance.

Implementation Method 1

a supercapacitor group (3) configured for being charged by a main supply voltage received from a main power source (6) of the motor vehicle during a normal operating condition or by an auxiliary supply voltage and for providing a backup supply voltage

Methodology Applied
Scientific EffectCapacitance: Capacitance

Implementation Method 2

an electric motor (4) configured for actuating the electronically controlled door latch (1) based on the main supply voltage or on the backup supply voltage

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 3

an unrechargeable auxiliary battery (5) configured for supplying an auxiliary supply voltage

Methodology Applied
Scientific EffectBattery (electricity): Battery (electricity)

Data Source

PatentEP4365393B1Electronically controlled door latch
Publication Date: 2025.08.20 KIEKERT AG
  • EP4365393B1 patent drawingFigure 1

AI summary

The invention relates to an electronically controlled door latch arrangement for a motor vehicle (2), the arrangement comprising an auxiliary battery (5) configured for supplying an auxiliary supply voltage, and an electronically controlled door latch (1) comprising a supercapacitor group (3) and an electric motor (4), whereby the supercapacitor group (3) is configured for being charged by a main supply voltage received from a main power source (8) of the motor vehicle (2) during a normal operating condition or by the auxiliary supply voltage and for providing a backup supply voltage during a backup operating condition when the main supply voltage is unavailable, and the electric motor (4) is configured for actuating the door latch (1) based on the main supply voltage or on the backup supply voltage.