Pouch Battery Lead Adhesion Structure for Overcharge Cutoff
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Solution Overview
Problem
Secondary batteries face safety risks due to potential ignition from overcharging, despite current interrupt devices (CID) that interrupt current supply, as heat dissipation issues can still lead to safety deterioration, necessitating a solution to delay the separation of leads and prevent ignition.
Innovation Solution
A secondary battery design with an adhesion unit containing metal particles, an adhesive material, and a high-voltage decomposition material that generates gas upon overcharging, accelerating pressure increase and delaying lead separation to quickly interrupt current supply, reducing ignition risk.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a current interrupt device (CID) is built in the secondary battery to interrupt current supply when internal pressure increases, then safety is improved, but the operation time of the CID is extended which may delay the interruption and worsen safety
Solution Approach 1:
The patent changes the physical-chemical parameters of the adhesion unit by incorporating a high-voltage decomposition material that undergoes decomposition at specific voltage thresholds. This material decomposition alters the adhesion characteristics dynamically, enabling the lead separation to occur at the appropriate time when overcharging is detected, thus resolving the contradiction between maintaining adhesion for normal operation and separating leads for safety interruption.
Solution Approach 2:
The high-voltage decomposition material acts as an intermediary substance within the adhesion unit. It mediates between the conflicting requirements of maintaining lead adhesion during normal operation and enabling lead separation during overcharging. The decomposition material responds to voltage changes and facilitates the timing-controlled separation, solving the safety timing issue.
2Object-affected harmful factors
If the first lead and second lead are separated quickly to interrupt current supply, then ignition risk is reduced, but the adhesion strength between leads is weakened which may cause premature separation
Solution Approach 1:
The adhesion unit's properties are made dynamic through the inclusion of high-voltage decomposition material. The adhesion strength is not static but changes in response to voltage conditions. During normal operation, the material maintains strong adhesion, but when overcharging occurs, the material decomposes and reduces adhesion strength, enabling lead separation. This dynamic behavior resolves the contradiction between strong adhesion and quick separation.
Solution Approach 2:
The high-voltage decomposition material is pre-installed in the adhesion unit to prepare for future overcharging events. This preliminary action ensures that when overcharging occurs, the decomposition reaction can immediately reduce adhesion strength and enable lead separation, rather than requiring additional time for detection and response mechanisms.
3Reliability
If additives and anti-ignition materials are added to the electrolyte to prevent ignition, then safety is improved, but the complexity of the battery composition increases
Solution Approach 1:
The patent extracts the safety function from the electrolyte composition and relocates it to the adhesion unit's high-voltage decomposition material. Instead of adding multiple additives to the electrolyte, the safety mechanism is implemented in the lead adhesion system. This extraction reduces electrolyte complexity while maintaining safety through the voltage-responsive decomposition material.
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 battery effectively reduces the risk of ignition by quickly interrupting current supply when overcharging occurs, leveraging the gas generation from the high-voltage decomposition material to enhance safety beyond existing CID structures.
Implementation Method 1
a high-voltage decomposition material that is decomposed to generate a gas when a high voltage raised above charging voltage due to overcharging is applied to accelerate the increase of the gas pressure
Implementation Method 2
an adhesion unit having conductivity and coupling the first lead and the second lead to each other
Data Source
Figure 1A
Figure 1B
Figure 2
AI summary
The present invention relates to a secondary battery. The secondary battery comprises: a pouch; an electrode assembly mounted within the pouch and having a structure in which electrodes and separators are alternately laminated, wherein a tab connection part in which electrode tabs expanded from ends of the electrodes overlap each other to be gathered to one side is provided; a lead comprising a first lead having one end connected to the tab connection part and a second lead having one end connected to the first lead and the other end extending to the outside of the pouch, wherein each of the first lead and the second lead is fixed to an inner surface of the pouch; and an adhesion unit having conductivity and coupling the first lead and the second lead to each other, wherein, when the pouch is expanded due to an increase of a gas pressure within the pouch, the first lead and the second lead is separated from each other, wherein a high-voltage decomposition material that is decomposed to generate a gas when a high voltage having a predetermined level or more is applied to accelerate the increase of the gas pressure is contained in the adhesion unit.