Battery Pack PCM Mechanical Connection Design

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Solution Overview

Problem

The existing secondary battery pack manufacturing process is complex, costly, and prone to defects due to the need for multiple welding or soldering processes, which complicates assembly and reduces safety, especially with lithium secondary batteries, as it requires numerous parts and precise welding, increasing the risk of errors and manufacturing costs.

Innovation Solution

A secondary battery pack design featuring a battery cell with a cathode/separator/anode structure, a protection circuit module (PCM) with connection members A and B, and an electrically insulated top cap, where connection member A is mechanically and electrically coupled to the first electrode terminal, and connection member B is connected to the second electrode terminal via a safety element, reducing the number of parts and simplifying assembly by using coupling grooves and a PCB, thereby minimizing the need for precise welding and enhancing safety.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If multiple welding or soldering processes are used to connect PCM to battery cell, then electrical connection is achieved, but assembly complexity increases and manufacturing cost increases

Engineering Contradiction:
Improveelectrical connection reliabilityVSAvoidassembly process complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces the welding/soldering process with a mechanical pressing connection system. The connection member includes a pressing portion that mechanically connects to the electrode terminal through a pressing groove, eliminating the need for welding or soldering processes while achieving reliable electrical connection between the PCM and battery cell.

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

Solution Approach 2:

The patent extracts the welding/soldering process from the assembly sequence and replaces it with a standalone mechanical pressing mechanism. The connection member is designed with an integrated pressing structure that achieves electrical connection through mechanical force alone, removing the complex thermal joining processes.

Inventive Principle:
Principle #2Taking out (Extraction)

2Reliability

If multiple insulative mounting members are used to achieve electrical isolation, then safety is improved, but the number of parts increases and assembly process becomes complicated

Engineering Contradiction:
Improveelectrical isolation reliabilityVSAvoidnumber of parts
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges the electrical isolation function with the connection structure itself. The connection member is designed with an insulating layer that provides electrical isolation between the pressing portion and other conductive parts, while the battery case provides additional isolation between the electrode terminal and external environment. This integration eliminates the need for separate insulative mounting members.

Inventive Principle:
Principle #5Merging (Combining)

3Reliability

If welding processes are used to connect nickel plates to electrode terminals, then electrical connection is achieved, but manufacturing precision requirements increase and defect ratio increases

Engineering Contradiction:
Improveelectrical connection stabilityVSAvoidwelding precision
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The patent replaces the precision-critical welding process with a mechanical pressing connection. The pressing portion of the connection member is designed to fit into the pressing groove with appropriate clearance and interference, achieving stable electrical connection through controlled mechanical force without requiring high welding precision.

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

4Ease of manufacture

If conventional battery cell structure is used, then manufacturing cost is maintained, but assembly process becomes more complex

Engineering Contradiction:
Improvebattery cell manufacturing costVSAvoidbattery pack assembly complexity
Core Design Contradiction:
Ease of manufactureVSDevice complexity

Solution Approach 1:

The connection member is designed as a universal component that can be applied to conventional battery cells without modifying the battery cell structure itself. The pressing groove is formed on the existing electrode terminal, and the connection member integrates multiple functions (electrical connection, mechanical support, electrical isolation) in a single component that works with standard battery cell designs.

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

Data Source

PatentEP2403035B1Rechargeable battery pack having a novel structure
Publication Date: 2018.11.14 LG CHEM LTD
  • EP2403035B1 patent drawingFigure 1~2
  • EP2403035B1 patent drawingFigure 3~4
  • EP2403035B1 patent drawingFigure 5~6

AI summary

Disclosed herein is a secondary battery pack including a battery cell including first and second electrode terminals of specific structures, a protection circuit module (PCM) including connection members A and B connected to the first and second electrode terminals and an electrically insulated top cap, wherein a connection portion of the connection member B connected to the second electrode terminal of the battery cell is located at the bottom of the PCB so that the connection member B is electrically connected to the second electrode terminal via the safety element, the connection member A is coupled to the bottom of the PCB in a state in which the connection member A protrudes from one end of the PCB in the lateral direction so that a connection portion of the connection member A connected to the first electrode terminal of the battery cell is exposed through a corresponding one of the through holes formed at the top cap, a coupling hole is formed at the protruding portion of the connection member A, and wherein coupling members are coupled into the respective coupling grooves of the battery cell through the through holes of the top cap in a state in which the PCM and the top cap are disposed at the top of the battery cell, and the connection member A is mechanically coupled and electrically connected to the first electrode terminal by a corresponding one of the coupling members.