Secondary Battery Tab-Through Cover Plate for Higher Energy Density
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Solution Overview
Problem
The energy density of secondary batteries is limited due to the space occupied by tabs and mechanical components within the casing, which reduces the amount of active material that can be accommodated.
Innovation Solution
The design includes a casing with a recessed cover plate and a sealing plate that allows the tab to pass through a relief hole, reducing the space occupied by the tab and enabling more active material to be used, while also improving safety and reducing production costs by eliminating the need for additional mechanical components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If tabs and mechanical components are disposed within the casing to connect electrode terminals, then electrical connection is achieved, but the internal space of the casing is occupied, reducing the energy density of the secondary battery
Solution Approach 1:
The patent extracts the tab connection function from the internal space of the casing. The tab extends through the cover plate to the external environment, eliminating the need for internal mechanical components like adaptor plates. This extraction of the connection path from the internal space directly increases the volume available for active material, resolving the contradiction between electrical connection reliability and energy density.
Solution Approach 2:
The patent changes the dimensional arrangement of the tab connection from a three-dimensional internal configuration to a two-dimensional surface configuration. The tab passes through the cover plate surface to establish external connection, transforming the connection geometry from occupying internal volume to utilizing external space, thereby increasing the active material volume within the casing.
2Quantity of substance
If tabs extend through the cover plate to external connection points, then space utilization is improved, but the cover plate structure becomes more complex
Solution Approach 1:
The patent segments the cover plate into functional zones: a sealing surface for sealing, a relief hole for tab passage, and a recessed portion for tab accommodation. This segmentation allows each zone to perform its specific function efficiently, managing the structural complexity by organizing it into distinct, purpose-driven segments rather than a monolithic complex structure.
Solution Approach 2:
The patent applies local quality by creating a recessed portion at the specific location where the tab passes through, rather than uniformly thickening the entire cover plate. This localized structural modification provides the necessary support and sealing only where needed, minimizing the overall structural complexity while achieving the required space utilization.
3Reliability
If a sealing plate is added to seal the relief hole, then sealing performance is improved, but the manufacturing process becomes more complex
Solution Approach 1:
The patent merges the sealing function with the cover plate structure itself. The recessed portion of the cover plate integrates the sealing surface and the tab accommodation into a single component, eliminating the need for a separate sealing plate. This merging reduces the number of parts and assembly steps, improving ease of manufacture while maintaining sealing performance through the integrated design.
Solution Approach 2:
The cover plate's recessed portion is designed to self-seal around the tab without requiring additional sealing components. The geometry of the recessed portion creates a natural sealing interface with the tab, allowing the cover plate to perform its own sealing function, thereby simplifying the manufacturing process while ensuring reliable sealing.
Data Source
AI summary
The embodiments of the present disclosure provide a secondary battery, a battery module, a battery pack, a device, and a manufacturing method. The secondary battery includes: an electrode unit, including a main body portion and a first tab and a second tab extending out from the main body portion; a casing, including an accommodating cavity for accommodating the main body portion and a first opening which is in communication with the accommodating cavity; a first cover plate capping the first opening, the first cover plate including a first relief hole penetrating therethrough, the first tab passes through the first relief hole and is connected to a side of the first cover plate facing away from the accommodating cavity; and a sealing plate, which is sealingly connected to the side of the first cover plate facing away from the accommodating cavity and covers the first relief hole.