Anchored Winding Core Structure for Thermal Runaway Containment

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Solution Overview

Problem

Electrochemical energy storage elements with high energy density face safety risks due to thermal failures, which can cause the winding core to be ejected as a projectile, leading to rapid thermal propagation and increased safety hazards, especially in networks of elements.

Innovation Solution

The energy storage element features a hollow cylindrical wound composite body with a helical structure, incorporating a winding core and an anchor element that projects laterally beyond the end face, forming a structural unit to prevent ejection and reduce velocity during thermal failure, enhancing safety by maintaining the core and contents within the cell assembly.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If high energy density is used in electrochemical energy storage elements, then energy storage capacity is improved, but thermal safety deteriorates due to risk of thermal runaway and projectile ejection

Engineering Contradiction:
Improveenergy storage capacityVSAvoidthermal safety
Core Design Contradiction:
Use of energy by moving objectVSReliability

Solution Approach 1:

The patent converts the harmful thermal runaway event into a beneficial safety mechanism by designing the winding core to be ejected preferentially during thermal failure. The core acts as a sacrificial component that, when ejected, creates internal void space that absorbs thermal energy and prevents propagation to neighboring cells, thus converting the harmful thermal event into a protective mechanism

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The winding core serves as an intermediary component between the high-energy electrochemical materials and the external environment. During normal operation, it provides structural support; during thermal runaway, it acts as a mediator that absorbs and redirects thermal energy through controlled ejection, preventing direct thermal propagation between cells

Inventive Principle:
Principle #24Intermediary (Mediator)

2Stability of the object's composition

If a winding core is used to stabilize the wound composite body, then structural integrity is improved, but safety deteriorates because the core can be ejected as a projectile during thermal failure

Engineering Contradiction:
Improvestructural integrityVSAvoidprojectile ejection hazard
Core Design Contradiction:
Stability of the object's compositionVSObject-affected harmful factors

Solution Approach 1:

The patent transforms the harmful projectile ejection effect into a beneficial safety feature by designing the winding core to be the preferred ejection target during thermal runaway. The core's ejection creates internal void space that absorbs thermal energy and prevents propagation, converting the hazard into a protective mechanism

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The patent applies different functional qualities to different parts of the system: the winding core is designed with specific material properties and geometric features (reduced axial length, controlled ejection characteristics) that differentiate it from the electrochemical components, allowing it to serve as a sacrificial element during thermal events while maintaining structural integrity during normal operation

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP4704196A1Electrochemical energy storage element
Publication Date: 2026.03.04 VARTA MICROBATTERY GMBH
  • EP4704196A1 patent drawingFigure 1~4
  • EP4704196A1 patent drawingFigure 5~10
  • EP4704196A1 patent drawingFigure 11~12

AI summary

An electrochemical energy storage element (12) comprises a 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) and an axially oriented cavity (46) in the center of the wound composite body (10). A winding core (50) is arranged in the cavity (46). To increase the safety of the energy storage element (12), an anchor element (52) is arranged on at least one of the two end faces (36) of the wound composite body (10) and is connected to the winding core (50). The anchor part (52) projects laterally from the axial center of the coiled composite body (10) over the end face (36) of the coiled composite body (10), at least in some areas.