Bipolar Battery Sealing Structure for Predictable Pressure Release
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Solution Overview
Problem
Bipolar batteries face challenges in predicting and managing damage due to internal pressure increases caused by temperature rises and gas generation, leading to unpredictable deformation of current collectors and frame body failure.
Innovation Solution
Incorporating a heterogeneous portion in the sealing portion with a lower melting point than the rest of the sealing structure, set to melt at or above the separator's shutdown temperature, to control and predict damage by releasing pressure when internal pressure rises.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a uniform sealing portion is used to contain the bipolar battery, then the sealing structure is simple and manufacturing is easier, but when internal pressure rises due to temperature increase, the damage location is unpredictable and safety cannot be ensured
Solution Approach 1:
The sealing portion is designed with heterogeneous structure where specific local regions have different melting points. The first heterogeneous portion contains a material with a melting point lower than the second heterogeneous portion, creating localized weak points that control where damage occurs when internal pressure rises, thus ensuring predictable safety behavior.
2Reliability
If the melting point of the heterogeneous portion is set very low, then pressure release occurs easily when temperature rises, but the separator cannot perform its shutdown function properly before the sealing portion damages
Solution Approach 1:
The melting points of the heterogeneous portions are carefully selected and coordinated with the separator's shutdown temperature. The first heterogeneous portion has a melting point higher than the separator's shutdown temperature to allow the separator to function first, while the second heterogeneous portion has a lower melting point to provide sequential pressure release, creating a controlled temperature-based response sequence.
3Ease of manufacture
If no heterogeneous portion is provided in the sealing portion, then the sealing structure is more uniform and easier to manufacture, but when internal pressure exceeds withstanding pressure, damage occurs at unpredictable locations making safety assessment difficult
Solution Approach 1:
Heterogeneous portions are pre-positioned in the sealing portion at specific locations with controlled melting points. These pre-designed weak points ensure that when internal pressure rises, damage will occur at these predetermined locations rather than randomly, making safety assessment and design much more reliable while maintaining manufacturing feasibility.
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 heterogeneous portion effectively manages pressure by melting and releasing it, ensuring safety by predicting and controlling the damage location, thus securing the battery's integrity.
Implementation Method 1
the heterogeneous portion having a melting point that is lower than a melting point of other portions of the sealing portion
Implementation Method 2
a separator as an electrolyte layer having a predetermined shutdown temperature
Data Source
AI summary
In a bipolar battery, a bipolar electrode is laminated and sealed in a sealing portion, and a separator having a predetermined shutdown voltage is interposed between a positive electrode layer and a negative electrode layer in the bipolar electrode. In the sealing portion, a heterogeneous portion is formed on the long side wall, and the heterogeneous portion has a melting point lower than the melting point of the other portion of the sealing portion and is equal to or higher than the shutdown voltage of the separator. Thus, in the bipolar battery, since the temperature in the sealing portion increases and the heterogeneous portion is more likely to be damaged than the other portions by reaching the melting point of the heterogeneous portion, the portion that may be damaged due to the temperature increase becomes clear, it is easy to secure the safety against damage.