Flexible Printed Circuit Welding for Battery Module Assembly

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Solution Overview

Problem

The existing methods for connecting flexible printed circuits to battery systems are cumbersome, cost-intensive, and require manual or semi-automatic processes, particularly when connecting battery modules and cell supervision circuits, which limits efficiency and scalability.

Innovation Solution

A method and tool for automatically unwinding, positioning, and welding a continuous strip-shaped flexible printed circuit to battery modules and cell supervision circuit boards, eliminating the need for additional holders and enabling fully automated assembly, allowing for various connection designs and flexible configurations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If manual or semi-automatic methods are used to connect flexible printed circuits to battery modules, then connection reliability can be maintained, but assembly efficiency and productivity are significantly reduced

Engineering Contradiction:
Improveassembly efficiencyVSAvoidautomation level
Core Design Contradiction:
ProductivityVSExtent of automation

Solution Approach 1:

The patent replaces manual mechanical connection operations with an automated welding system. The welding device automatically positions and welds the flexible printed circuit to the battery module contact portions, eliminating the need for manual holder manipulation and semi-automatic positioning while maintaining reliable electrical connections.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The flexible printed circuit is designed to be self-positioning through its flexibility, allowing it to naturally conform to the battery module surface during the automated welding process without requiring additional holding structures or manual intervention for alignment.

Inventive Principle:
Principle #25Self-service

2Manufacturing precision

If additional holders are used to maintain flexible printed circuit during connection, then positioning accuracy is improved, but device complexity and manufacturing cost increase

Engineering Contradiction:
Improvepositioning accuracyVSAvoidholder structure complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent extracts and eliminates the additional holder component from the connection system. By relying on the flexible printed circuit's inherent flexibility and the automated welding process, the solution removes the complexity of holder structures while maintaining sufficient positioning accuracy through the welding tool's positioning capabilities.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The flexible printed circuit serves its own positioning function through its flexibility, naturally conforming to the battery module surface and maintaining contact without requiring external holding structures. The material's inherent properties provide the necessary positioning capability.

Inventive Principle:
Principle #25Self-service

3Adaptability or versatility

If flexible printed circuit is used instead of rigid connections, then adaptability to cell swelling and spatial displacements is improved, but connection reliability during assembly may deteriorate

Engineering Contradiction:
Improveadaptability to cell swellingVSAvoidconnection reliability
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent changes the physical state of the connection from rigid to flexible by using a flexible printed circuit. This parameter change allows the connection to adapt to cell swelling and spatial displacements while maintaining electrical contact. The flexibility parameter enables the circuit to deform with battery expansion without breaking the electrical connection.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The flexible printed circuit provides beforehand cushioning by its inherent flexibility, allowing it to absorb and compensate for future cell swelling and spatial displacements before they occur. The flexible material acts as a buffer that maintains electrical contact despite dimensional changes in the battery cells.

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

4Productivity

If continuous strip-shaped flexible printed circuit is used, then manufacturing efficiency is improved, but material length and waste increase

Engineering Contradiction:
Improvemanufacturing efficiencyVSAvoidFPC material waste
Core Design Contradiction:
ProductivityVSLoss of substance

Solution Approach 1:

The patent applies preliminary action by providing the flexible printed circuit in a continuous strip shape before assembly. This allows the entire circuit to be positioned and welded in one continuous operation rather than assembling separate segments, improving manufacturing efficiency while enabling precise cutting to minimize waste after positioning.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The continuous strip-shaped flexible printed circuit is segmented into individual connection portions after positioning. This segmentation approach allows for precise cutting at the required locations, minimizing material waste while maintaining the manufacturing efficiency benefits of the continuous strip format during the assembly process.

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 approach enables a fully automated, efficient, and cost-effective connection process for flexible printed circuits to battery systems, improving assembly efficiency and scalability while maintaining reliable electrical contact even with cell swelling or spatial displacements.

Implementation Method 1

a weld connection is formed between a flexible printed circuit (FPC) and a battery module (50)

Methodology Applied
Scientific EffectWelding: Welding

Data Source

PatentEP3849006A1Battery system with flexible printed circuit
Publication Date: 2021.07.14 SAMSUNG SDI CO LTD
  • EP3849006A1 patent drawingFigure 1(A)~1(B)
  • EP3849006A1 patent drawingFigure 2~3
  • EP3849006A1 patent drawingFigure 4~5(C)

AI summary

The present invention relates to a method for connecting a flexible printed circuit, FPC, (20) to a battery system (100). Therein, a coil (25) of a continuous and strip-shaped FPC (20) is provided and a first section (21) of the FPC (20) is unwounded from the coil (25) and positioned over a first contact portion (51) of the battery module (50). A weld connection (40) is then formed between a conductive structure (24) of the FPC (20) in the first section (21) and the first contact portion (51). Further, a second section (22) of the FPC (20) is unwound from the coil (25) and positioned over at least one contact pad (31) of a cell supervision circuit board, CSCB, (30). Then, a weld connection (40) between the conductive structure (24) of the FPC (20) in the second section (22) and the at least one contact pad (31) of the CSCB (30) is formed. Finally, the first and second sections (21, 22) of the FPC (20) are cut from the coil (25). The present invention further relates to a tool (70) for connecting a flexible printed circuit, FPC, (20) to a battery module (50) in a method according to the invention, wherein the tool (70) comprises a tool head (71) with a coil holder (75) that is configured for receiving a coil of a continuous and strip-shaped FPC (20). The present invention further relates to a battery system (100) that comprises a plurality of battery modules (50), wherein a contact portion (51) of each battery module is connected to a contact pad (31) of a cell supervision circuit board, CSCB, (30) via a flexible printed circuit (20) in a method according to the present invention.