Spiral-Wound Rechargeable Battery Cap Assembly for Ultra-Small Cells

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Solution Overview

Problem

There is a need for ultra-small rechargeable batteries with high energy density and improved structural stability, particularly for wearable devices, which require efficient packaging within limited space while maintaining low weight and high electrical capacity.

Innovation Solution

The rechargeable battery design includes an electrode assembly with a spiral-wound configuration, a case with a cap assembly that uses a thermal fusion member made of an electrically insulating material for bonding and insulation, and a terminal plate configuration that allows for efficient sealing and electrical connectivity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If the battery size is reduced to ultra-small dimensions for wearable devices, then the device portability and wearability are improved, but the electrical capacity and energy density become insufficient

Engineering Contradiction:
Improvebattery sizeVSAvoidelectrical capacity
Core Design Contradiction:
Volume of moving objectVSQuantity of substance

Solution Approach 1:

The patent implements a nested structure where the separator is positioned between the first and second electrodes, with the electrode assembly nested within the case, and the cap assembly nested within the opening of the case. This nested arrangement maximizes space utilization and achieves ultra-small battery dimensions while maintaining adequate electrical capacity through efficient spatial organization of all components.

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The patent transitions from traditional planar battery layouts to a three-dimensional configuration with the electrode assembly arranged vertically within the case, utilizing the height dimension effectively. The cap assembly seals the opening at the top, creating a compact cylindrical structure that optimizes volume utilization and achieves high energy density in ultra-small dimensions.

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

2Device complexity

If the battery components are minimized and assembly process is simplified, then the manufacturing efficiency and ease of production are improved, but the structural stability and reliability may deteriorate

Engineering Contradiction:
Improvenumber of componentsVSAvoidstructural stability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent combines multiple functions into integrated components: the cap assembly serves both as a structural closure and as an electrical terminal connection point; the separator simultaneously provides electrical insulation between electrodes and structural support within the electrode assembly; the case houses both the electrode assembly and provides mechanical protection. This merging of functions reduces the total number of components while maintaining structural stability and reliability.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The cap assembly is designed with multi-functionality, serving as both the sealing element for the case opening and the electrical terminal for external connections. The thermal fusion member provides both mechanical bonding and electrical insulation functions. This multi-functional design reduces component count while ensuring structural integrity and reliable operation.

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

3Weight of moving object

If the battery weight is reduced for better portability, then the wearability and energy efficiency per weight are improved, but the structural strength and durability may be compromised

Engineering Contradiction:
Improvebattery weightVSAvoidstructural strength
Core Design Contradiction:
Weight of moving objectVSStrength

Solution Approach 1:

The patent employs thin-film structures for the separator and cap plate, which provide adequate mechanical strength and structural stability while minimizing weight. The separator as a thin film maintains electrical insulation and structural integrity between electrodes, and the thin cap plate provides sufficient sealing and terminal support without adding excessive weight, achieving optimal weight-to-strength ratio for ultra-small wearable batteries.

Inventive Principle:
Principle #30Flexible shells and thin films

4Ease of manufacture

If the cap assembly uses a simplified bonding structure, then the manufacturing process is simplified and production time is reduced, but the sealing effectiveness and electrical insulation may be insufficient

Engineering Contradiction:
Improveassembly processVSAvoidsealing effectiveness
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent replaces complex mechanical bonding systems with thermal fusion bonding. The thermal fusion member is bonded to the cap plate through thermal fusion, providing both mechanical attachment and electrical insulation in a single simplified process step. This thermal fusion method achieves reliable sealing and insulation without requiring multiple mechanical fastening operations, thereby simplifying the manufacturing process while ensuring sealing effectiveness.

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

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 design achieves an ultra-small size with improved electrical capacity, low weight, and structural stability, making it suitable for wearable devices while simplifying the manufacturing process and ensuring effective insulation and bonding.

Implementation Method 1

a thermal fusion member between the terminal plate and the cap plate and thermally fused with the terminal plate and the cap plate

Methodology Applied
Scientific EffectThermal fusion: Melting

Data Source

PatentEP3783713B1Rechargeable battery
Publication Date: 2025.02.19 SAMSUNG SDI CO LTD
  • EP3783713B1 patent drawingFigure 1
  • EP3783713B1 patent drawingFigure 2
  • EP3783713B1 patent drawingFigure 3

AI summary

A rechargeable battery includes: an electrode assembly (200) including a first electrode (11), a second electrode (12), and a separator (13) between the first electrode (11) and the second electrode (12); a case (190) having an opening and housing the electrode assembly (200); and a cap assembly (100) sealing the opening of the case (190), wherein the cap assembly includes: a cap plate (120) bonded to the case (190) and covering the opening; a terminal plate (140) bonded to the cap plate (120); and a thermal fusion member (160) between the terminal plate (140) and the cap plate (120) and thermally fused with the terminal plate (140) and the cap plate (120).