Pouch Cell Vent Member Layout for Directed Gas Discharge
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Solution Overview
Problem
Conventional secondary batteries face challenges in safely discharging gases in a specific direction, which can lead to thermal propagation and potential damage due to rapid temperature rises.
Innovation Solution
A secondary battery design featuring a vent member with a vent resin having a lower melting point than the sealant resin, positioned in the sealing portion's extension, to direct gas discharge away from the electrode lead, minimizing direct contact and enhancing safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a lithium secondary battery is charged at high temperature (e.g., 60°C or higher), then charging speed can be improved, but internal pressure increases and battery safety deteriorates
Solution Approach 1:
The patent changes the physical state of the electrolyte from liquid to gel by using gel electrolyte, which fundamentally alters the temperature-dependent behavior of the battery. This parameter change allows the battery to maintain stable internal pressure across a wide temperature range (-30°C to 60°C) while enabling fast charging at high temperatures without the pressure issues associated with liquid electrolytes.
Solution Approach 2:
The patent uses a composite gel electrolyte formed by mixing polymer electrolyte and liquid electrolyte in specific ratios (70:30 to 30:70 by weight). This composite material combines the advantages of both components: the polymer provides structural stability and low-temperature performance, while the liquid component ensures high-temperature ionic conductivity and safety, resolving the contradiction between charging speed and internal pressure.
2Productivity
If liquid electrolyte is used to enable fast charging, then charging speed improves, but battery safety deteriorates at high temperature due to increased internal pressure
Solution Approach 1:
The patent changes the physical state of the electrolyte from liquid to gel, which fundamentally alters the temperature-dependent behavior of the battery. This parameter change allows the battery to maintain stable internal pressure across a wide temperature range (-30°C to 60°C) while enabling fast charging at high temperatures without the pressure issues associated with liquid electrolytes.
Solution Approach 2:
The patent uses a composite gel electrolyte formed by mixing polymer electrolyte and liquid electrolyte in specific ratios (70:30 to 30:70 by weight). This composite material combines the advantages of both components: the polymer provides structural stability and low-temperature performance, while the liquid component ensures high-temperature ionic conductivity and safety, resolving the contradiction between charging speed and battery safety.
3Quantity of substance
If battery capacity is increased to provide higher energy density, then energy storage improves, but heat generation increases leading to safety issues
Solution Approach 1:
The patent uses a composite gel electrolyte formed by mixing polymer electrolyte and liquid electrolyte in specific ratios (70:30 to 30:70 by weight). This composite material combines the advantages of both components: the polymer provides structural stability and low-temperature performance, while the liquid component ensures high-temperature ionic conductivity and safety, resolving the contradiction between charging speed and battery safety.
Solution Approach 2:
The patent changes the physical state of the electrolyte from liquid to gel, which fundamentally alters the temperature-dependent behavior of the battery. This parameter change allows the battery to maintain stable internal pressure across a wide temperature range (-30°C to 60°C) while enabling fast charging at high temperatures without the pressure issues associated with liquid electrolytes.
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 design effectively directs gas discharge away from the electrode lead, reducing the risk of damage and improving overall battery safety by minimizing direct gas contact with temperature-sensitive components.
Implementation Method 1
a positive electrode, a negative electrode, and a gel electrolyte
Implementation Method 2
the separator may have a heat-resistant structure
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
Disclosed herein is a secondary battery having a vent member. The secondary battery may include an electrode assembly to which an electrode lead is attached, a case including an accommodation portion. The accommodation portion may be defined by a bent side and a sealing portion. The accommodation portion may be configured to receive the electrode assembly and seal the electrode assembly therein. The sealing portion may contain a sealant resin to form a seal around the electrode assembly. The sealing portion may include an extension adjacent to and extending from the bent side. The vent member may be disposed at least partially in the extension. The vent member may include a vent resin having a lower melting point than the sealant resin.