Battery Tab Rupture for Short-Circuit Safety

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Solution Overview

Problem

High-power lithium secondary batteries face challenges with existing PTC elements, which have low capacity and increase in size when scaled up, making them impractical for high-power applications.

Innovation Solution

A safety apparatus is designed with integrated PTC function in the tab of a high power lithium secondary battery, featuring a casing with first and second electrode plates, a separator, and tabs that rupture upon short-circuit to interrupt electrical conduction, preventing explosions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional PTC elements are used in high-power lithium secondary batteries, then safety against short-circuit is improved, but the PTC element size increases and becomes impractical for high-power applications

Engineering Contradiction:
Improvesafety against short-circuitVSAvoidPTC element size
Core Design Contradiction:
ReliabilityVSVolume of moving object

Solution Approach 1:

The patent merges the PTC safety function with the existing tab structure of the battery. The tab, which is already present for electrical connection, is designed to incorporate PTC material, eliminating the need for separate PTC elements. This integration maintains safety functionality while avoiding additional volume increase.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The tab is given multiple functions: it serves both as the electrical connection component and as the PTC safety device. By making the tab universal for both purposes, the patent avoids adding dedicated PTC elements that would increase battery volume.

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

2Power

If the PTC capacity is increased to handle high-power applications, then the PTC can protect against higher currents, but the size of the PTC increases making it impractical

Engineering Contradiction:
ImprovePTC current handling capacityVSAvoidPTC element size
Core Design Contradiction:
PowerVSVolume of moving object

Solution Approach 1:

The PTC function is combined with the tab structure, which already has the necessary spatial presence for high-power applications. The tab's inherent size and position allow it to handle high currents while incorporating PTC material, avoiding the need for separate large-capacity PTC elements.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent changes the physical or chemical parameters of the tab material to achieve high PTC capacity. By modifying the tab's material composition or structural parameters, the PTC effect is enhanced to handle high-power applications without proportionally increasing volume.

Inventive Principle:
Principle #35Parameter changes

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 solution effectively prevents explosions in high power batteries during short-circuits by integrating the PTC function into the tab, allowing for a compact and cost-effective implementation without additional space or connection requirements.

Implementation Method 1

when current rapidly increases

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Implementation Method 2

the tab comprises a portion which ruptures when the first tab and the second tab are short-circuited

Methodology Applied
Scientific EffectThermal expansion: Thermal Expansion

Implementation Method 3

The PTC element is a device that interrupts electrical conduction by using the positive resistance-temperature characteristic, i.e. positive temperature coefficient (PTC), of a conductive polymer, which changes conductivity through heat expansion.

Methodology Applied
Scientific EffectPositive temperature coefficient (PTC): Thermal Expansion

Data Source

PatentEP1987555B1Safety apparatus using high power battery
Publication Date: 2011.12.14 SK INNOVATION CO LTD
  • EP1987555B1 patent drawingFigure 1
  • EP1987555B1 patent drawingFigure 2~3
  • EP1987555B1 patent drawingFigure 4~5

AI summary

Disclosed is a safety apparatus for responding to a battery short-circuit, and more particularly a safety apparatus for use in the event of a short-circuited of a high power battery, in which a PTC function is integrated into a tab of a high power battery. The safety apparatus for responding to a short-circuit of a high power battery comprises a casing (212), a battery part (211) including a first electrode plate (211a), a separator (211c), and a second electrode plate (211b) arranged in that order and disposed inside the casing (212), a first tab (213) connected to one of four edges of the first electrode plate (211a) via a first tab welding part (213a) and protruding from the casing (212), and a second tab (214) connected to one of four edges of the second electrode plate (211b) via a second tab welding part (214a) and protruding from the casing (212), wherein a portion of the first tab (213) ruptures when the first tab (213) and the second tab (214) are short-circuited, thus preventing the first electrode plate (211a) and the second electrode plate (211b) from being short-circuited.