Battery Cap Plate Structure for Stiffness and Ignition Resistance
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Solution Overview
Problem
Conventional secondary batteries face issues with durability due to cap plate bending and deformation, and the formation of alloys on the inner surface of the case, which can lead to ignition risks, particularly when a negative electrode is short-circuited.
Innovation Solution
The secondary battery design includes a cap plate with protrusions and a high-resistance charging member made of a polymer and conductive filler, which secures rigidity, prevents alloy formation, and consumes short-circuit energy, while reducing terminal plate thickness to minimize weight.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If the cap plate is made thinner to reduce weight, then the cell weight is reduced, but the cap plate becomes more prone to bending and deformation
Solution Approach 1:
The cap plate is segmented by adding protrusions that divide the plate into distinct regions. These protrusions act as structural reinforcements that prevent bending and deformation while allowing the overall plate thickness to be reduced for weight savings.
Solution Approach 2:
The charging member is constructed as a composite material combining polymer and conductive filler. This composite structure provides both the necessary electrical functionality and mechanical reinforcement to the cap plate, enabling weight reduction while maintaining strength.
2Device complexity
If a conventional charging member is used, then the battery structure is simple, but alloy formation on the case inner surface can occur leading to ignition risks
Solution Approach 1:
The electrical resistance parameter of the charging member is changed by using a high-resistance composite material (polymer with conductive filler). This parameter change prevents alloy formation on the case inner surface by controlling current distribution, thereby eliminating ignition risks while maintaining structural simplicity.
3Weight of moving object
If the terminal plate thickness is reduced to minimize weight, then the cell weight decreases, but the structural integrity may be compromised
Solution Approach 1:
The charging member is designed with localized protrusions that concentrate reinforcement at critical areas around the terminal plate. This local quality approach provides structural support where needed most, allowing the terminal plate to be thinner overall while maintaining integrity at stress points.
Data Source
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AI summary
The present invention provides a secondary battery having enhanced durability, reinforced cap plate stiffness and reduced cell weight. Disclosed as an example is a secondary battery having: an electrode assembly; a case for accommodating the electrode assembly; a cap plate coupled to the case to seal the electrode assembly; a terminal connected to the electrode assembly and exposed through the cap plate; and a protrusion protruding toward the terminal in the area in which the terminal of the cap plate is coupled.