Pouch Battery Sealing Preheating for Uniform Seal Force

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Solution Overview

Problem

The sealing force of the sealing part in secondary batteries is reduced due to heat loss through the electrode lead, leading to non-uniform sealing and potential defects during continuous manufacturing.

Innovation Solution

A preheating member is used to heat the sealing part and sealing blocks to a preheat temperature lower than the seal temperature, minimizing heat loss through the electrode lead and ensuring uniform heating of the sealing part, thereby maintaining consistent sealing force throughout the manufacturing process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a lead heater system is introduced to supply heat to the electrode lead, then heat loss through the electrode lead is minimized and sealing force is increased, but there is a temperature difference in the entire pouch and sealing force difference occurs

Engineering Contradiction:
Improvesealing forceVSAvoiduniformity of sealing force
Core Design Contradiction:
StrengthVSManufacturing precision

Solution Approach 1:

The patent applies preliminary action by preheating the sealing part and sealing blocks before the actual sealing process. The preheating member heats the sealing part of the pouch and the sealing blocks to a preheat temperature lower than the seal temperature, so when sealing occurs, the electrode lead is already at a higher temperature, reducing heat loss and minimizing temperature differences across the pouch, thereby achieving more uniform sealing force.

Inventive Principle:
Principle #10Preliminary action

2Productivity

If sealing is performed continuously through the sealing block, then productivity is increased, but the temperature of the heat source gradually decreases and sealing force becomes non-uniform

Engineering Contradiction:
Improvecontinuous sealing capabilityVSAvoidtemperature stability of sealing block
Core Design Contradiction:
ProductivityVSTemperature

Solution Approach 1:

The preheating member performs preliminary heating of the sealing blocks before each sealing operation. This ensures that even during continuous manufacturing, the sealing blocks maintain their temperature, preventing the gradual temperature decrease that would otherwise occur and ensuring consistent sealing force throughout the production process.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent implements continuity of useful action by maintaining the sealing blocks at a stable temperature through preheating, allowing continuous sealing operations to proceed without interruption or temperature degradation. The preheating member ensures the heat source remains effective throughout the entire continuous manufacturing process.

Inventive Principle:
Principle #20Continuity of useful action

3Loss of time

If the sealing part is heated to seal temperature directly, then sealing process is completed quickly, but heat loss through the electrode lead reduces sealing force

Engineering Contradiction:
Improvesealing timeVSAvoidsealing force
Core Design Contradiction:
Loss of timeVSStrength

Solution Approach 1:

The patent applies preliminary action by preheating the sealing part and sealing blocks to a preheat temperature before the actual sealing process. This preliminary heating reduces the temperature differential between the sealing components and the electrode lead, minimizing heat loss during sealing while still achieving complete sealing in a reasonable time frame.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent changes the temperature parameter by introducing a two-stage temperature approach: a preheat temperature (lower than seal temperature) for preliminary heating, and then the seal temperature for the actual sealing process. This parameter change optimizes both sealing force and sealing time by reducing heat loss during the transition to sealing temperature.

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 enhances the sealing force of the sealing part, prevents heat loss, and ensures uniform sealing quality, increasing productivity by reducing the time required for sealing and minimizing defects.

Implementation Method 1

a preheating member that preheats each of the sealing part of the pouch and the pair of sealing blocks to a preheat temperature

Methodology Applied
Scientific EffectHeat conduction: Conduction (thermal)

Implementation Method 2

a sealing process of sealing a sealing part of the pouch using a pair of sealing blocks. In the sealing process, the sealing part of the pouch may be sealed by raising a temperature of the pair of sealing blocks to apply heat to the sealing part

Methodology Applied
Scientific EffectHeat conduction: Conduction (thermal)

Data Source

PatentEP4403336B1Device and method for manufacturing secondary battery
Publication Date: 2025.09.10 LG ENERGY SOLUTION LTD
  • EP4403336B1 patent drawingFigure 1
  • EP4403336B1 patent drawingFigure 2
  • EP4403336B1 patent drawingFigure 3

AI summary

A device for manufacturing a secondary battery according to the present invention includes: a pair of sealing blocks that are disposed at both sides, respectively, of a sealing part of a pouch from which an electrode lead is drawn out, and compress and seal the sealing part at a seal temperature and pressure; and a preheating member that preheats each of the sealing part of the pouch and the pair of sealing blocks to a preheat temperature, wherein the preheating member includes a first heating body that preheats to the preheat temperature a surface of the sealing part, on which each of the pair of sealing blocks is disposed, and a second heating body that preheats to the preheat temperature a surface of each of the pair of sealing blocks, which faces the sealing part.