Cylindrical Battery Cap Assembly With Internal Injection Plug

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Solution Overview

Problem

Existing cylindrical secondary batteries face challenges in efficiently connecting both the positive and negative electrodes to external terminals due to their insulation requirements, necessitating a new terminal connection structure.

Innovation Solution

A cylindrical secondary battery design featuring a cap assembly with an injection plug comprising a cylindrical body, a pressing part, and a separating part, allowing for simplified electrode connection and improved electrolyte injection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a traditional cylindrical secondary battery structure with separate negative and positive electrode terminals is used, then the electrodes can be insulated from each other, but the terminal connection structure becomes complex and difficult to manufacture

Engineering Contradiction:
Improveterminal connection structureVSAvoidterminal connection structure
Core Design Contradiction:
Ease of manufactureVSDevice complexity

Solution Approach 1:

The patent combines both the positive electrode terminal and negative electrode terminal into a single cap assembly. The cap assembly includes a cap body with a positive electrode terminal and a negative electrode terminal, eliminating the need for separate terminal structures. This merging of functions reduces the overall device complexity while maintaining ease of manufacture, as the single cap assembly can be produced and installed as one unit rather than requiring multiple separate components.

Inventive Principle:
Principle #5Merging (Combining)

2Device complexity

If both positive and negative electrodes are disposed on one side of the battery, then the terminal connection is simplified, but the insulation between electrodes becomes more difficult to achieve

Engineering Contradiction:
Improveterminal connection structureVSAvoidelectrode insulation
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent employs a nested structure where the positive electrode and negative electrode are both disposed within the cap assembly in a vertically stacked arrangement. The positive electrode extends from the cap body downward into the battery can, while the negative electrode is positioned below it with proper spacing. This nested configuration allows both electrodes to be connected to external terminals through the single cap assembly while maintaining reliable insulation between them through the structured spatial arrangement and insulating materials.

Inventive Principle:
Principle #7Nested doll (Nesting)

3Adaptability or versatility

If a complex terminal connection structure is used to accommodate both electrodes on one side, then electrode connection is achieved, but the manufacturing process efficiency decreases

Engineering Contradiction:
Improveelectrode configurationVSAvoidmanufacturing process efficiency
Core Design Contradiction:
Adaptability or versatilityVSProductivity

Solution Approach 1:

The cap assembly is designed as a multi-functional component that simultaneously serves as the closure for the battery can, the connection point for both positive and negative electrodes, and the seal for the battery interior. The cap body includes both a positive electrode terminal and a negative electrode terminal, allowing it to perform multiple functions in a single structure. This universality enables the battery to accommodate both electrodes on one side while maintaining simple manufacturing processes, as the cap assembly can be produced using standard cap manufacturing techniques rather than requiring complex custom-built terminal structures.

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

Data Source

PatentEP4224623B1Cylindrical secondary battery
Publication Date: 2025.10.22 SAMSUNG SDI CO LTD
  • EP4224623B1 patent drawingFigure 1
  • EP4224623B1 patent drawingFigure 2
  • EP4224623B1 patent drawingFigure 3A

AI summary

A secondary battery according to an embodiment of the present disclosure includes: an electrode assembly having a positive electrode plate and a negative electrode plate; a case for accommodating the electrode assembly and having one side open; a pair of current collector plates electrically connected to the electrode assembly and the case, respectively; and a cap assembly including a cap plate that seals the case and has an injection hole formed therethrough and an injection plug that seals the injection hole from the inside of the case. According to an embodiment of the present disclosure, an electrolyte injection structure may be improved, and thus process efficiency may be improved. In addition, since both the positive electrode and the negative electrode are formed in one direction of the secondary battery, a connection structure with an external terminal may be simplified.