Integrated Pre-Charge Power Distribution Unit for EV Contactors

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Solution Overview

Problem

Conventional power distribution units in electrical applications, such as electric vehicles, face challenges with large inrush currents causing damage to contacts and requiring time-consuming, complex assembly processes.

Innovation Solution

A power distribution unit with a housing containing a main contactor and a pre-charge assembly, including a resistor and switch, is integrated with a controller that activates the pre-charge driver to charge a capacitor before powering the main contactor, minimizing inrush currents and simplifying assembly by reducing the need for separate mechanical and electrical connections.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a pre-charge circuit is used to eliminate inrush currents and protect the main contactor, then contact damage is reduced and operating life is extended, but device complexity increases due to additional components (pre-charge contactor, pre-charge resistor)

Engineering Contradiction:

Improvecontactor contact protectionVSAvoidnumber of components

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines the main contactor and pre-charge circuit into a single integrated unit. The pre-charge resistor is integrated within the main contactor housing, and the pre-charge switch is formed by a portion of the main contactor's movable contact assembly. This merging eliminates the need for separate pre-charge contactors and resistors, reducing component count while maintaining the protective function against inrush currents.

Inventive Principle:

Principle #5Merging (Combining)

2Ease of manufacture

If individual components are separately mounted to a common frame with separate mechanical and electrical connections, then assembly is straightforward, but assembly time is significant and space occupation is large

Engineering Contradiction:

Improveassembly simplicityVSAvoidassembly time

Core Design Contradiction:

Ease of manufactureVSLoss of time

Solution Approach 1:

The patent integrates multiple components (main contactor, pre-charge resistor, pre-charge switch, controller) into a single housing unit. This consolidation eliminates the need for separate mounting of components to a common frame and reduces the number of mechanical and electrical connections required, thereby significantly reducing assembly time and simplifying the manufacturing process.

Inventive Principle:

Principle #5Merging (Combining)

3Area of stationary object

If individual components are separately mounted, then component replacement is easy, but the unit occupies significant space within the vehicle

Engineering Contradiction:

Improvespace occupationVSAvoidcomponent replaceability

Core Design Contradiction:

Area of stationary objectVSEase of repair

Solution Approach 1:

While integrating components into a single housing, the patent maintains functional segmentation through distinct cavities (main cavity for the contactor, secondary cavity for the controller) and modular internal arrangements. This allows the entire power distribution unit to be replaced as a single module, achieving space savings while maintaining ease of repair at the system level.

Inventive Principle:

Principle #1Segmentation

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

This solution reduces contact damage from inrush currents and streamlines assembly by integrating components within a single housing, enhancing reliability and cost-effectiveness.

Implementation Method 1

The main contactor includes a coil assembly energized to move the movable contact between the unmated position and the mating position

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

A typical pre-charge circuit includes a pre-charge contactor in series with a pre-charge resistor. During power-up of the vehicle, the pre-charge contactor is closed and current flows through the pre-charge contactor and the pre-charge resistor

Methodology Applied

Scientific EffectJoule heating: Joule Heating

Data Source

PatentUS11465513B2Power distribution unit having contactor with integrated pre-charge circuit

Publication Date: 2022.10.11 TE CONNECTIVITY SOLUTIONS GMBH

AI summary

A power distribution unit includes a housing, a main contactor in a main cavity of the housing, and a pre-charge assembly in a secondary cavity of the housing. The main contactor includes first and second fixed contacts and a movable contact configured to electrically connect the first and second fixed contacts in a mated position. The main contactor includes a coil assembly energized to move the movable contact. The pre-charge assembly includes a pre-charge resistor and a pre-charge switch coupled to the pre-charge resistor. The power distribution unit includes a controller received in the housing. The controller includes a main contactor driver for powering the main contactor and a pre-charge driver for powering the pre-charge switch.