Bus Bar and FPCB Assembly With Direct Welded Cell Sensing

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Flexible printed circuit boards (FPCBs) in bus bar assemblies for battery cells are prone to damage and require complex welding processes, leading to structural weakness and increased costs.

Innovation Solution

Direct bonding of a flexible printed circuit board's connection circuit portion to a bus bar using welding processes like laser or ultrasonic welding, with enhanced coupling structures to simplify connections and reduce part count.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Weight of moving object

If a flexible printed circuit board is used to connect battery cells, then the connection is lightweight and space-saving, but the FPCB is easily torn or damaged by external impact

Engineering Contradiction:
Improveweight of connection componentVSAvoiddamage resistance of FPCB
Core Design Contradiction:
Weight of moving objectVSReliability

Solution Approach 1:

The connection system is divided into multiple components: rigid support structures (frames, bus bars) and the flexible circuit board. The rigid components provide impact resistance while the FPCB provides electrical connection, separating the protective function from the conductive function.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Rigid support structures and frames are installed beforehand to provide mechanical protection and cushioning for the flexible circuit board. These structures absorb external impacts before they can reach and damage the thin FPCB, preventing tearing and damage in advance.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

2Ease of manufacture

If protrusions are used to connect the FPCB to the bus bar, then electrical connection is achieved, but the coupling structure is weak and prone to failure

Engineering Contradiction:
Improvesimplicity of connection processVSAvoidcoupling strength between FPCB and bus bar
Core Design Contradiction:
Ease of manufactureVSStrength

Solution Approach 1:

The protrusion is designed to extend through both the bus bar and the FPCB, merging these components into a single integrated assembly. This through-extension creates a unified structure where the protrusion acts as a common element binding both parts together, significantly strengthening the coupling while maintaining manufacturing simplicity.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The connection is enhanced by extending the protrusion in the third dimension (through the entire assembly rather than just surface-level attachment). This dimensional extension transforms a weak surface connection into a strong through-connection that spans multiple components, dramatically improving coupling strength.

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

3Adaptability or versatility

If multiple separate components are used for connection, then flexibility in configuration is achieved, but the number of parts and manufacturing complexity increases

Engineering Contradiction:
Improvebattery connection configuration flexibilityVSAvoidnumber of connection parts
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The bus bar with integrated protrusions serves multiple functions: electrical connection, mechanical support, and structural integration with the FPCB. This multi-functional design reduces the need for separate connection components while maintaining the ability to configure different battery arrangements, as the same bus bar structure can adapt to various connection patterns.

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

Solution Approach 2:

Multiple functions are merged into single components: the bus bar combines electrical conduction, mechanical support, and connection features (protrusions) into one element. This consolidation reduces part count and manufacturing complexity while preserving configuration flexibility, as the integrated design can accommodate different battery layouts without requiring additional specialized components.

Inventive Principle:
Principle #5Merging (Combining)

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

Simplifies the welding process, improves structural integrity, reduces costs, and enhances productivity by directly bonding the FPCB to the bus bar, allowing flexible configuration of battery connections.

Implementation Method 1

Direct bonding of a flexible printed circuit board's connection circuit portion to a bus bar using welding processes like laser or ultrasonic welding

Methodology Applied
Scientific EffectLaser welding: Laser Beam Welding

Implementation Method 2

Direct bonding of a flexible printed circuit board's connection circuit portion to a bus bar using welding processes like laser or ultrasonic welding

Methodology Applied
Scientific EffectUltrasonic welding: Ultrasonic Vibration

Data Source

PatentEP3565021B1Bus bar assembly and frame assembly
Publication Date: 2026.03.18 YURA CORP CO LTD
  • EP3565021B1 patent drawingFigure 1
  • EP3565021B1 patent drawingFigure 2
  • EP3565021B1 patent drawingFigure 3

AI summary

A bus bar assembly installed in a frame for fixing a plurality of stacked battery cells is provided. The bus bar assembly may include: a bus bar fixed to the frame; a flexible printed circuit board electrically connected to the bus bar and configured to sense the plurality of battery cells; and a connection terminal having a protrusion formed on one surface of the connection terminal, is the protrusion being configured to pass through the flexible printed circuit board so as to be electrically connected to the flexible printed circuit board, and the connection terminal configured to be electrically connected to the bus bar through the opposite surface of the one surface, the opposite surface being bonded to the bus bar.