Integrated Fuse and Pre-Charge Resistor for Compact HV Protection

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Solution Overview

Problem

Existing high voltage circuits in new energy vehicles require large and costly pre-charging resistors and fuses, occupying significant space and increasing production costs.

Innovation Solution

A fusing device integrating a pre-charging resistor and a fuse element within a single unit, where the pre-charging resistor is wound around an inner housing and the fuse element is received in a receiving cavity, with conductive terminals connecting to both ends, allowing for both pre-charging and overcurrent/short circuit protection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If pre-charging resistor and fuse are arranged separately in high voltage circuits, then each component can perform its function independently, but the volume and cost increase significantly

Engineering Contradiction:
Improveindependent protection functionVSAvoiddevice volume
Core Design Contradiction:
ReliabilityVSVolume of stationary object

Solution Approach 1:

The patent combines the pre-charging resistor and fuse into a single integrated device. The resistor element and fuse element are housed together with shared terminal connections, eliminating the need for separate mounting spaces while maintaining independent functional operation of each component.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The integrated device performs multiple functions: pre-charging limitation through the resistor element, overcurrent protection through the fuse element, and unified terminal connectivity. This multi-functional design allows a single component to replace what previously required two separate components, reducing overall device volume.

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

2Reliability

If pre-charging resistor and fuse are arranged separately, then each component can be optimized independently, but production cost increases

Engineering Contradiction:
Improveprotection functionVSAvoidproduction cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

By merging the resistor and fuse into a single housing with shared terminal structures and common mounting requirements, the patent reduces the total number of assembly steps, fasteners, and installation operations needed, thereby lowering production costs despite maintaining independent functional optimization.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The multi-functional integrated device reduces bill of materials (BOM) complexity and inventory requirements. Manufacturers can produce a single standardized component that fulfills multiple protection needs, reducing per-unit costs through economies of scale and simplified supply chain management.

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

3Reliability

If pre-charging resistor and fuse are arranged separately, then each component provides dedicated protection, but space occupation increases

Engineering Contradiction:
Improvefault protectionVSAvoidspace occupation
Core Design Contradiction:
ReliabilityVSArea of stationary object

Solution Approach 1:

The patent merges the resistor and fuse into a single compact housing that occupies one mounting location rather than two separate locations. The internal arrangement allows both elements to coexist in a space-efficient configuration while maintaining their dedicated protection functions.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The resistor element and fuse element are nested within the same housing structure, with one component positioned inside or adjacent to the other. This nesting arrangement maximizes space utilization and minimizes the overall footprint of the protection device.

Inventive Principle:
Principle #7Nested doll (Nesting)

4Volume of stationary object

If pre-charging resistor and fuse are integrated, then volume and cost are reduced, but device complexity increases

Engineering Contradiction:
Improvedevice volumeVSAvoidintegration complexity
Core Design Contradiction:
Volume of stationary objectVSDevice complexity

Solution Approach 1:

While integrating multiple functions, the patent maintains clear segmentation between the resistor element, fuse element, and terminal structures. Each functional component remains distinct and independently replaceable, which simplifies manufacturing and assembly processes despite the integrated housing.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The integrated device uses universal terminal connections and standardized mounting interfaces that simplify the overall system integration. By designing the housing and terminals to serve multiple functions simultaneously, the patent reduces the number of separate connection points and mounting operations required.

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

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

The integrated fusing device reduces space and weight, lowers production costs, and enhances flexibility by combining pre-charging and protection functions, ensuring safe current thresholds and rapid fault response.

Implementation Method 1

a pre-charging resistor is a resistor that slowly charges high-voltage electrical components such as capacitors at the beginning of high-voltage power-on of the entire vehicle

Methodology Applied
Scientific EffectElectrical Resistance: Electrical Resistance

Implementation Method 2

a pre-charging resistor is a resistor that slowly charges high-voltage electrical components

Methodology Applied
Scientific EffectJoule Heating: Joule Heating

Implementation Method 3

when each high voltage loop has short circuit and overcurrent faults, the current fuse is fused in time to cut off the loop

Methodology Applied
Scientific EffectJoule Heating: Joule Heating

Implementation Method 4

the current fuse is fused in time to cut off the loop

Methodology Applied
Scientific EffectMelting: Melting

Data Source

PatentEP4089711B1Multifunctional fuse
Publication Date: 2025.11.19 BYD CO LTD
  • EP4089711B1 patent drawingFigure 1
  • EP4089711B1 patent drawingFigure 2
  • EP4089711B1 patent drawingFigure 3

AI summary

The present disclosure provides a fusing device. The fusing device includes a fuse element, a pre-charging resistor, and an inner housing. The inner housing is provided with a receiving cavity, the fuse element is received in the receiving cavity, and the pre-charging resistor is wound around an outer side of the inner housing and is in contact with the inner housing. The fusing device of the present disclosure resolves problems of large volumes and high costs of a pre-charging resistor and a fuse in a high voltage circuit in the related art.