Cylindrical Battery Cell Winding Core for Controlled Shorting

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Solution Overview

Problem

Electrochemical energy storage devices with high energy density face safety risks due to potential short circuits causing thermal dynamics and uncontrolled pressure release, which can lead to casing rupture and fire hazards, especially under mechanical deformation.

Innovation Solution

An electrochemical energy storage element with a cylindrical housing and a hollow cylindrically shaped wound composite body, featuring a helical structure with conductive winding core that connects electrode strips upon axial deformation, allowing controlled discharge and preventing uncontrolled pressure release.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If high energy density is achieved in electrochemical energy storage devices, then energy storage capacity is improved, but safety risk increases due to potential short circuits causing thermal dynamics and uncontrolled pressure release

Engineering Contradiction:
Improveenergy storage capacityVSAvoidsafety risk
Core Design Contradiction:
Use of energy by moving objectVSReliability

Solution Approach 1:

A pressure equalization valve is introduced as an intermediary component between the sealed housing and the external environment. This valve provides a controlled pathway for pressure release, preventing uncontrolled rupture while maintaining the high energy density benefits of the sealed design. The valve acts as a safety mediator that allows controlled venting of gas and pressure without compromising the overall structural integrity or energy storage capacity.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The housing is designed to be substantially airtight and sealed, creating an inert atmosphere that prevents atmospheric oxygen from entering the cell. This inert environment eliminates the risk of fire and oxidation reactions, even when thermal dynamics occur during short circuits. The sealed environment maintains safety by isolating the electrochemical materials from reactive atmospheric gases.

Inventive Principle:
Principle #39Inert atmosphere (Inert environment)

2Strength

If pressure equalization valve is activated to prevent uncontrolled rupture, then structural safety is improved, but atmospheric oxygen enters the cell increasing fire risk

Engineering Contradiction:
Improvestructural safetyVSAvoidfire risk
Core Design Contradiction:
StrengthVSObject-affected harmful factors

Solution Approach 1:

The housing is designed to be substantially airtight and sealed, creating an inert atmosphere that prevents atmospheric oxygen from entering the cell. This inert environment eliminates the risk of fire and oxidation reactions, even when thermal dynamics occur during short circuits. The sealed environment maintains safety by isolating the electrochemical materials from reactive atmospheric gases.

Inventive Principle:
Principle #39Inert atmosphere (Inert environment)

Solution Approach 2:

The pressure equalization valve serves as a controlled intermediary that manages pressure release without compromising the airtight seal. It provides a regulated pathway for pressure equalization while maintaining the overall sealed environment, thus preventing both uncontrolled rupture and oxygen ingress.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Adaptability or versatility

If housing undergoes axial deformation, then mechanical tolerance is improved, but electrical short circuit risk increases between positive and negative electrodes

Engineering Contradiction:
Improvemechanical toleranceVSAvoidshort circuit risk
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

Electrically insulating elements are introduced as intermediaries between the positive and negative electrodes. These insulating elements prevent direct electrical contact between oppositely polarized electrodes during axial deformation, while still allowing the housing to accommodate mechanical tolerances and deformation. The insulating elements act as protective mediators that maintain electrical isolation under mechanical stress.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The design incorporates electrically insulating elements in advance to prevent potential short circuits before they can occur. These insulating elements are positioned to provide protective cushioning against electrical contact during axial deformation, addressing the short circuit risk proactively rather than reactively.

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

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

The conductive winding core ensures safe operation by enabling controlled discharge, reducing the risk of thermal runaway and ingress of atmospheric oxygen, thereby enhancing safety and preventing uncontrolled rupture.

Implementation Method 1

the winding core is electrically conductive, and the winding core is designed and/or arranged such that, in the event of axial deformation of the housing, it electrically connects the first electrically conductive contact element and the second electrically conductive contact element

Methodology Applied
Scientific EffectElectrical conduction: Conduction (electrical)

Implementation Method 2

One partial reaction, occurring at a comparatively lower redox potential, takes place at the negative electrode, while the other, occurring at a comparatively higher redox potential, takes place at the positive electrode

Methodology Applied
Scientific EffectOxidation: Oxidation

Implementation Method 3

One partial reaction, occurring at a comparatively lower redox potential, takes place at the negative electrode, while the other, occurring at a comparatively higher redox potential, takes place at the positive electrode

Methodology Applied
Scientific EffectReduction: Reduction

Implementation Method 4

an ion current corresponding to the electrode reaction occurs within the electrochemical cell. This is ensured by the ion-conducting electrolyte

Methodology Applied
Scientific EffectIon conduction: Conduction (electrical)

Data Source

PatentEP4712178A1Electrochemical energy storage element
Publication Date: 2026.03.18 VARTA MICROBATTERY GMBH
  • EP4712178A1 patent drawingFigure 1~4
  • EP4712178A1 patent drawingFigure 5
  • EP4712178A1 patent drawingFigure 6

AI summary

An electrochemical energy storage element (12) comprises a hollow cylindrical wound composite body (10) with a spiral structure consisting of at least two electrode strips (14, 24) wound spirally around a winding axis and at least one separator strip (38, 40) arranged between the electrode strips (14, 24). The hollow cylindrical wound composite body (10) includes two end faces (34, 36), a circumferential outer surface (42), and an axially oriented cavity (46) in the center of the composite body (10) in which an electrically conductive winding core (50) is arranged. The wound composite body (10) is arranged in a cylindrical housing (60) with a base (61) and a cover (62), such that the end faces (34, 36) point towards the base (61) and the cover (62).The energy storage element (12) further comprises electrically conductive contact elements (70, 80) which lie flat on the end faces (34, 36). It is proposed that the winding core (50) be designed and/or arranged such that, in the event of axial deformation of the housing (60), it electrically connects the first electrically conductive contact element (70) and the second electrically conductive contact element (80).