Multi-directional Lead-tab Structure for High Current Lithium Battery
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Solution Overview
Problem
Conventional pouch type lithium rechargeable batteries face issues with heat generation and sealing when used for high current applications, as the existing lead-tab structure is not optimized for large current demands, leading to safety concerns and moisture penetration.
Innovation Solution
The battery employs a multidirectional lead-tab structure by alternately stacking electrode plates with different axial direction positions for tabs of the same or different polarity, providing multiple leads at corresponding positions, including two positive and two negative electrode leads at four sides, with specific width and thickness ranges to manage current effectively and enhance sealing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a conventional single lead-tab structure is used, then the battery case sealing is simpler, but heat generation increases and safety concerns arise in high current applications
Solution Approach 1:
The patent divides the single lead-tab structure into multiple lead-tabs (at least two positive electrode leads and at least two negative electrode leads) distributed at different positions around the electrode assembly. This segmentation distributes the current flow across multiple pathways, reducing current density and heat generation at any single point, thereby improving safety in high current applications.
Solution Approach 2:
The patent transitions from a conventional single-point lead-tab connection to a multi-directional distributed lead-tab structure. The leads are positioned at different axial and radial locations around the electrode assembly, adding spatial distribution in multiple dimensions. This dimensional expansion optimizes current distribution and thermal management.
2Reliability
If the lead-tab structure is optimized for high current, then safety improves, but sealing complexity increases due to multiple lead positions
Solution Approach 1:
The insulation film is designed to perform multiple functions: it provides electrical insulation between the electrode leads and battery case, seals the interface between leads and case, and protects against moisture ingress. This multi-functionality simplifies the overall sealing structure by combining insulation and sealing functions in a single component.
Solution Approach 2:
The patent uses uniform insulation films (such as polyethylene terephthalate or polypropylene) consistently across all lead-tab positions and interfaces. This homogeneous approach simplifies manufacturing and sealing processes compared to using different materials or complex multi-layer structures at different locations.
3Reliability
If multiple leads are positioned at different axial directions, then current distribution is optimized, but manufacturing precision requirements increase
Solution Approach 1:
The patent specifies practical parameter ranges for lead positioning (axial direction positions and radial distances) that balance current distribution optimization with manufacturing feasibility. These parameter ranges allow sufficient current distribution benefit while accommodating normal manufacturing tolerances, avoiding overly strict precision requirements.
4Ease of manufacture
If conventional lead-tab sizes are used, then manufacturing is simpler, but heat generation increases in high current applications
Solution Approach 1:
Instead of using a single large lead-tab that would generate excessive heat, the patent segments the current path into multiple smaller lead-tabs. Each lead-tab handles a portion of the total current, reducing current density and heat generation while maintaining ease of manufacture with conventional lead-tab dimensions and materials.
Data Source
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AI summary
A lithium rechargeable battery, and more particularly, a lithium rechargeable battery having a multidirectional lead-tab structure is provided. The lithium rechargeable battery includes: an electrode assembly in which a separation film and an electrode plate having a current collector, an active material, and a tab are alternately stacked; a lead electrically connected to the tab; and a battery case, wherein the lead is divided into a positive electrode lead and a negative electrode lead, and at least one positive electrode lead and at least one negative electrode lead are provided. The lithium rechargeable battery is appropriate for using a high current even while using a conventional lead-tab size.