Traction Battery Charging Safety Loop for Fault Isolation

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Solution Overview

Problem

Existing traction battery charging arrangements for motor vehicles face challenges with unreliable immediate disconnection in case of faults, particularly due to interference, delays, and the risk of overheating or fire from high electrical currents, which can lead to safety hazards.

Innovation Solution

A traction battery charging arrangement featuring an electrical safety loop with a loop current source, controllable loop openers, and sensors that detect faults to instantly switch off the charging current, ensuring safety by isolating the charging circuit and using a separate supply unit with galvanic isolation to prevent ground loops and reduce noise emissions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of information

If digital communication lines are used for communication between charging arrangement components, then communication capability is improved, but the system becomes insensitive to interference and delays particularly when components are spatially further apart

Engineering Contradiction:
Improvecommunication reliabilityVSAvoidcommunication system complexity
Core Design Contradiction:
Loss of informationVSDevice complexity

Solution Approach 1:

The patent introduces a safety loop as an intermediary communication channel between charging components. This separate physical loop provides a dedicated, interference-resistant path for safety-critical signals, distinct from the main digital communication lines. The loop acts as a mediator that ensures reliable fault detection and immediate disconnection commands can be transmitted even when digital communication experiences interference or delays.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Power

If high electrical currents are flowed in the charging lines, then charging power is improved, but the risk of overheating or fire increases

Engineering Contradiction:
Improvecharging powerVSAvoidoverheating and fire risk
Core Design Contradiction:
PowerVSObject-affected harmful factors

Solution Approach 1:

The patent implements preliminary safety actions by continuously monitoring charging parameters and maintaining a ready-to-act disconnection mechanism. Before dangerous conditions develop, the system preemptively detects anomalies through the safety loop and can immediately interrupt charging current flow. This preliminary detection and response capability prevents the escalation to overheating or fire conditions even when high charging currents are being delivered.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The safety loop provides continuous feedback about the charging system's operational state. Temperature sensors, current sensors, and other monitoring devices feed information back through the safety loop to the control system, enabling real-time adjustments to charging parameters or immediate disconnection if dangerous conditions are detected. This feedback mechanism allows high power charging to proceed safely by continuously verifying that temperature and current remain within safe limits.

Inventive Principle:
Principle #23Feedback

3Reliability

If immediate disconnection is implemented in case of fault, then safety is improved, but the system requires complex monitoring and control mechanisms

Engineering Contradiction:
ImprovesafetyVSAvoidmonitoring and control system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent segments the safety system into distinct functional modules: a separate safety loop for fault detection, dedicated sensors for monitoring specific parameters (temperature, current, voltage), and a control unit that processes safety signals independently from the main charging control. This segmentation allows each component to be optimized for its specific function and simplifies the overall system architecture by separating safety-critical functions from normal charging operations, making the complex safety requirements more manageable.

Inventive Principle:
Principle #1Segmentation

4Object-affected harmful factors

If charging station is placed remotely from supply unit, then noise emissions are reduced, but communication and control between components becomes more difficult

Engineering Contradiction:
Improvenoise emissionsVSAvoidcommunication reliability
Core Design Contradiction:
Object-affected harmful factorsVSLoss of information

Solution Approach 1:

The safety loop serves as a dedicated intermediary communication channel that bridges the gap between the remotely placed charging station and the supply unit. This separate physical loop provides a reliable path for safety-critical signals to traverse the distance without being affected by electromagnetic interference from the power electronics or other noise sources. The loop ensures that fault detection and disconnection commands can be transmitted reliably across the remote connection.

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP3517341B1Traction battery charging arrangement
Publication Date: 2021.12.08 DR ING H C F PORSCHE AG
  • EP3517341B1 patent drawingFigure 1
  • EP3517341B1 patent drawingFigure 2

AI summary

The invention relates to a traction battery charging arrangement (10) for charging a traction battery of a motor vehicle. The charging arrangement (10) comprises a charging station (50) which has a charging plug (56) for establishing an electrical charging connection with the traction battery of the motor vehicle. Furthermore, the charging arrangement (10) comprises an electrical safety loop (60) which includes a loop current source (53), at least one controllable loop opener (601-605), and at least one loop current sensor (701, 702). A charging current control device (34, 52) switches off the charging current when the loop current sensor (701, 702) does not detect a loop current.