Pouch Battery Tab Geometry to Prevent Internal Short Circuits
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Solution Overview
Problem
Shape abnormalities in the tabs of a pouch-type rechargeable battery can cause short circuits, reducing operational safety and leading to defects.
Innovation Solution
The rechargeable battery design includes an electrode assembly with a separation layer and electrode tabs that satisfy specific geometric equations, ensuring standardized dimensions and parallel alignment of electrode tabs and leads, minimizing deformation and optimizing internal geometry to prevent short circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If tabs are bent and welded in the space between electrode assembly and battery case, then electrical connection is achieved, but shape abnormalities occur causing short circuits
Solution Approach 1:
The patent applies preliminary action by pre-bending the tabs to a predetermined angle (30-60 degrees) before assembly, and pre-positioning the electrode lead with its bent portion. This preliminary configuration ensures that when components are assembled, the tabs and leads naturally align without requiring post-assembly bending or welding that could cause deformation. The predetermined angles are calculated in advance to account for thermal expansion and contraction during charge-discharge cycles, preventing shape abnormalities before they occur.
Solution Approach 2:
The patent utilizes parameter changes by establishing specific geometric relationships between components through mathematical equations. The distance E between bent portions is defined as E = B × (0.73 to 0.77), where B is the electrode assembly thickness. The height C of electrode tabs is set as C = D × (0.3 to 0.7), where D is the distance from case-lead coupling to electrode assembly end. These parameter specifications ensure optimal spacing that prevents tab deformation while maintaining electrical connection reliability.
2Ease of manufacture
If tabs are arranged to be bent for connection, then electrical connection is established, but shape abnormalities cause short circuits
Solution Approach 1:
The patent applies preliminary action by pre-bending the tabs to a predetermined angle (30-60 degrees) before assembly, and pre-positioning the electrode lead with its bent portion. This preliminary configuration ensures that when components are assembled, the tabs and leads naturally align without requiring post-assembly bending or welding that could cause deformation. The predetermined angles are calculated in advance to account for thermal expansion and contraction during charge-discharge cycles, preventing shape abnormalities before they occur.
Solution Approach 2:
The patent introduces an intermediary element - the electrode lead with a predetermined bent portion - that mediates between the electrode tabs and the battery case. This lead acts as a buffer that absorbs dimensional variations and prevents direct contact between tabs and case walls. The lead's bent portion creates a controlled geometric relationship that maintains proper spacing, preventing tabs from deforming into positions that would cause short circuits while simplifying the assembly process.
3Manufacturing precision
If geometric equations are applied for standardized dimensions, then manufacturing precision is improved, but design complexity increases
Solution Approach 1:
The patent utilizes parameter changes by establishing specific geometric relationships between components through mathematical equations. The distance E between bent portions is defined as E = B × (0.73 to 0.77), where B is the electrode assembly thickness. The height C of electrode tabs is set as C = D × (0.3 to 0.7), where D is the distance from case-lead coupling to electrode assembly end. These parameter specifications ensure optimal spacing that prevents tab deformation while maintaining electrical connection reliability.
Solution Approach 2:
The patent applies local quality by focusing geometric constraints only on critical dimensions where shape abnormalities occur, rather than controlling all dimensions. The equations specifically target the distance E between bent portions and the height C of electrode tabs, which are the key parameters affecting short circuit risk. Other dimensions can vary within broader tolerances, simplifying manufacturing while maintaining precision where it matters most for preventing tab deformation.
Data Source
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AI summary
A rechargeable battery (100) includes an electrode assembly (200) including electrode plates (210) and electrode tabs (211) extending from each of the electrode plates (210) and having a bent portion (211a). An electrode lead (300) connected to the electrode tabs (211) has a bent portion, and a case (400) accommodates the electrode assembly (200). The electrode assembly (200), the electrode lead (300), and the case (400) satisfy a first equation E = B * (0.73 to 0.77) and a second equation C = D * 0.3 to 0.7. B indicates thickness of the electrode assembly (200), C indicates height of the electrode tabs (211), D indicates distance from or of a coupled portion of the case (400) and the electrode lead (300) to the electrode assembly (200), and E indicates distance between the bent portions (211a).