Secondary Battery Ground Member Diverts Abnormal Current

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Solution Overview

Problem

Secondary batteries, particularly pouch-type batteries used in large-sized packs, face safety risks due to potential electrolyte leakage and direct contact between electrodes leading to abnormal current flow, heat, and sparks upon external impact, posing a fire hazard.

Innovation Solution

Incorporating a ground member and ground terminal in the electrode stack to divert abnormal current to the outside, preventing heat and spark generation by grounding the electrode stack, which includes a conductive ground member and ground line to safely discharge excess current.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Weight of moving object

If a pouch-type battery structure is used to reduce weight and manufacturing cost, then the battery achieves low weight and low cost, but the mechanical strength is insufficient leading to electrolyte leakage and fire risk

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

Solution Approach 1:

The patent applies beforehand cushioning by introducing a ground member and ground line that provide a predetermined safe path for abnormal current before it can cause harmful effects. This protective structure is built into the battery design in advance, creating a cushion against potential fire hazards from nail penetration or external impacts.

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

2Weight of moving object

If the battery case has low mechanical strength to maintain light weight, then the battery achieves light weight, but pyrotechnic substance leaks and fire risk increases

Engineering Contradiction:
Improvebattery weightVSAvoidfire risk
Core Design Contradiction:
Weight of moving objectVSObject-affected harmful factors

Solution Approach 1:

The patent uses an intermediary approach by introducing a ground member and ground line that act as a mediator between the electrodes and the external environment. This intermediary structure provides a controlled path for abnormal current, preventing uncontrolled current flow that would cause fire, while allowing the battery case to remain lightweight.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Quantity of substance

If electrodes are positioned close together to increase energy density, then the battery achieves high energy density, but direct contact causes abnormal current and fire hazard

Engineering Contradiction:
Improveenergy densityVSAvoidfire hazard
Core Design Contradiction:
Quantity of substanceVSObject-affected harmful factors

Solution Approach 1:

The patent applies taking out by extracting the harmful abnormal current from the electrode system and directing it through a separate ground path. The ground member and ground line separate the abnormal current flow from the electrodes, allowing high energy density positioning while preventing fire hazards from direct electrode contact.

Inventive Principle:
Principle #2Taking out (Extraction)

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

Enhances safety by ensuring abnormal currents flow externally, reducing the risk of fire and heat generation during external impacts, thereby improving the battery's mechanical strength and safety.

Implementation Method 1

the abnormal current may flow to the outside through the ground part to prevent the heat and the sparks from being generated

Methodology Applied
Scientific EffectElectrical conduction: Conduction (electrical)

Data Source

PatentEP3333940B1Secondary battery
Publication Date: 2023.05.03 LG ENERGY SOLUTION LTD
  • EP3333940B1 patent drawingFigure 1
  • EP3333940B1 patent drawingFigure 2
  • EP3333940B1 patent drawingFigure 3

AI summary

The present invention relates to a secondary battery. The secondary battery according to the present invention comprises an electrode stack in which an electrode and a separator are combined with each other and a ground part grounding the electrode stack to the outside, wherein the ground part comprises a ground member disposed at one side of the separator to allow abnormal current flowing from the electrode to the one side of the separator to be introduced therein.