Stacked Secondary Battery Separator Layout for Impact Reliability
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Solution Overview
Problem
The enlargement of secondary batteries for battery electric vehicles increases the weight of the electrode body, leading to a higher risk of damage from impacts and vibrations, compromising the reliability of the battery.
Innovation Solution
A secondary battery design featuring a stacked-type electrode body with a zigzag-bent separator and a wound part, accompanied by an insulating sheet covering the outer surface of a separator overlap area, to enhance protection against damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the size of the secondary battery is enlarged to extend cruising distance, then the capacity and cruising distance are improved, but the weight of the electrode body increases leading to higher risk of damage from impact and vibration
Solution Approach 1:
The separator is designed with a zigzag-bent configuration that creates overlapping regions acting as cushioning zones. When impact or vibration occurs, these overlapping regions deform and absorb the mechanical stress before it reaches the electrodes, providing beforehand cushioning protection. The bent structure with multiple layers in overlap regions serves as a mechanical buffer that mitigates the harmful effects of external forces on the electrode body.
2Use of energy by moving object
If the weight of the electrode body is increased to provide higher capacity, then the energy storage is improved, but the susceptibility to damage from impact and vibration increases
Solution Approach 1:
The zigzag-bent separator acts as an intermediary protective layer between the electrodes and external mechanical forces. The overlapping regions of the bent separator create a buffer zone that mediates the transmission of impact and vibration forces, reducing the direct mechanical stress on the electrodes while allowing the battery to maintain high energy storage capacity through increased electrode mass.
3Reliability
If a zigzag-bent separator is used to protect electrodes from damage, then the reliability is improved, but the structural complexity of the electrode body increases
Solution Approach 1:
The separator is segmented into multiple functional regions: straight portions that maintain basic separation, zigzag-bent portions that provide mechanical protection, and overlapping regions that act as cushioning zones. This segmentation allows each portion to perform its specific function efficiently while collectively providing comprehensive electrode protection without excessive overall complexity.
Solution Approach 2:
The separator employs a zigzag-bent curved structure instead of a straight configuration. The curved/bent geometry creates overlapping regions that naturally absorb mechanical stress through deformation, providing protective functionality while maintaining a relatively simple continuous structure that can be manufactured as a single piece.
Data Source
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AI summary
A secondary battery (100) in which a problem in a conventional art is solved is provided. A secondary battery according to the present disclosure includes: a stacked-type electrode body (20) that includes a plurality of first electrode plates (23), a plurality of second electrode plates (24) with a polarity different from a polarity of the first electrode plates, and a separator (25) with a band-like shape; a battery case (10); and an insulating sheet (50). The separator includes a zigzag-bent part that is bent in a zigzag manner so that the separator is disposed between the first electrode plate and the second electrode plate, and a wound part that is wound to an outer periphery of a part where the first electrode plates, the second electrode plates, and the zigzag-bent part are stacked. The zigzag-bent part includes a first bent part that is disposed on one side in a direction perpendicular to a stacking direction of the first electrode plate and the second electrode plate, and a second bent part that is disposed on the other side in the direction perpendicular to the stacking direction of the first electrode plate and the second electrode plate. A separator overlap part where the wound part overlaps twice or more is provided outside the first bent part. The insulating sheet is disposed on an outer surface side of the separator overlap part.