On-Board Charger PCB Stacking for Higher Power Density

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Solution Overview

Problem

Existing vehicle-mounted chargers for electric vehicles are large in size due to the need for increased power, which requires more devices on the main board, leading to a larger circuit board that cannot accommodate additional components without increasing size.

Innovation Solution

The charger is redesigned with a compact structure by dividing the circuit board into multiple boards, including a main circuit board and auxiliary boards, with components strategically arranged to maximize space utilization and incorporating cooling water passages and thermal management systems to enhance power density and reduce electromagnetic interference.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the power of the vehicle-mounted charger is increased to accelerate charging speed, then the charging speed is improved, but the size of the main board and charger increases

Engineering Contradiction:
Improvecharging speedVSAvoidcharger size
Core Design Contradiction:
ProductivityVSVolume of moving object

Solution Approach 1:

The patent divides the original single main board into multiple separate circuit boards (power conversion board, control board, driver board). This segmentation allows each board to be optimized independently and arranged to maximize space utilization, enabling higher power density without increasing overall charger size.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent transitions from a two-dimensional flat board layout to a three-dimensional stacked arrangement of multiple circuit boards. By utilizing the vertical dimension and stacking boards in layers with optimized spatial arrangement, the design achieves higher power density while maintaining a compact footprint.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Power

If more devices are arranged on the main board to increase power, then the power is improved, but the main board cannot accommodate more devices due to projection area constraints

Engineering Contradiction:
Improvecharger powerVSAvoidmain board area
Core Design Contradiction:
PowerVSArea of stationary object

Solution Approach 1:

The patent segments the circuit devices into multiple functional boards, each handling specific power conversion tasks. This allows the system to achieve higher total power by distributing components across multiple boards rather than congesting a single board's projection area.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent implements a nested arrangement where multiple circuit boards are stacked and positioned in overlapping projections. The boards are arranged such that their projection areas overlap, creating a nested doll-like structure that maximizes space utilization and enables higher power density within the same footprint.

Inventive Principle:
Principle #7Nested doll (Nesting)

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 redesign results in a smaller vehicle-mounted charger with improved power density and reduced electromagnetic interference, while maintaining power levels, by optimizing space usage and heat dissipation.

Implementation Method 1

a cooling water passage is arranged in the housing, and the vertical auxiliary board is attached to a side wall of the cooling water passage

Methodology Applied
Scientific EffectForced Convection: Forced Convection

Implementation Method 2

a thermal grease or a thermal adhesive is coated between the aluminum substrate and the side wall of the cooling water passage

Methodology Applied
Scientific EffectThermal Conduction: Conduction (thermal)

Data Source

PatentEP4709066A1On-board charger having compact structure
Publication Date: 2026.03.11 SHENZHEN VMAX NEW ENERGY (GROUP) CO LTD
  • EP4709066A1 patent drawingFigure 1~2
  • EP4709066A1 patent drawingFigure 3~4
  • EP4709066A1 patent drawingFigure 5~6

AI summary

The present invention discloses a vehicle-mounted charger with a compact structure. The vehicle-mounted charger comprises a housing and a main circuit board arranged inside the housing. At least one auxiliary circuit board is arranged below the main circuit board, and an electric connection member is arranged between the main circuit board and the auxiliary circuit board; in a vertical direction, a second size component is arranged in a position at which the main circuit board is not overlapped with the auxiliary circuit board, a first size component is arranged in a position at which the main circuit board is overlapped with the auxiliary circuit board, and the first size component is arranged on the auxiliary circuit board; and a whole circuit board in the prior art is divided into a plurality of circuit boards.