Battery Cell Housing Geometry for Sealing and Energy Density
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Solution Overview
Problem
Existing lithium-ion batteries face challenges in achieving high energy density and safety performance, with issues such as aluminum plastic film breakage, packaging failure, and electrolyte leakage during safety tests, leading to reduced yield and increased production costs.
Innovation Solution
A battery cell design that equally distributes forces on the electrode assembly by optimizing the structural dimensions of the electrode assembly and housing, including specific relationships between the housing thickness, lateral edge radii, and edge projections, to enhance space efficiency and sealing integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the housing thickness and lateral edge dimensions are not optimized, then the manufacturing is simpler, but the safety performance deteriorates due to aluminum plastic film breakage and packaging failure
Solution Approach 1:
The patent applies parameter changes by establishing specific mathematical relationships between housing dimensions (thickness T2, lateral edge radius R, edge projection Z) and electrode assembly thickness T1. The formulas (T2-Z)/2 ≤ R ≤ T1/2 + 0.3 and 0.2T2 ≤ Z ≤ T2 - 0.4 define optimal parameter ranges that prevent film breakage while maintaining structural simplicity.
Solution Approach 2:
The patent uses curvature by designing the lateral edge with a rounded arc shape instead of a sharp corner. The arc radius R creates a curved transition that distributes stress evenly during expansion, preventing concentration at corners that would cause aluminum plastic film breakage.
2Quantity of substance
If the housing structure is simplified without optimized dimensions, then the manufacturing is easier, but the energy density deteriorates due to reduced space efficiency
Solution Approach 1:
The patent optimizes space utilization by defining precise parameter relationships that minimize empty space. The lateral edge arc radius R and projection Z are calculated to fit the electrode assembly tightly, maximizing the quantity of active materials that can be packed into the housing volume.
Solution Approach 2:
The patent applies partial action by providing just enough housing thickness T2 and edge projection Z to accommodate the electrode assembly thickness T1 with minimal clearance. The formulas ensure sufficient space for the electrode while avoiding excessive housing material that would reduce energy density.
3Reliability
If the lateral edge dimensions are not properly designed, then the manufacturing is simpler, but the sealing integrity deteriorates due to flaring and breakage
Solution Approach 1:
The patent ensures sealing integrity by defining the lateral edge arc radius R and projection Z within specific ranges. These parameters prevent flaring by creating a gradual curvature transition that maintains uniform stress distribution, keeping the sealing edges intact during battery expansion.
Solution Approach 2:
The rounded lateral edge with arc radius R prevents stress concentration at sharp corners that would cause sealing failure. The curved geometry distributes expansion forces evenly along the sealing perimeter, maintaining integrity without requiring complex reinforcement structures.
4Reliability
If the housing thickness is increased to improve safety, then the safety performance improves, but the energy density deteriorates due to reduced active material space
Solution Approach 1:
The patent determines the optimal housing thickness T2 by establishing a mathematical relationship with the electrode assembly thickness T1 and the edge projection Z. The formula (T2-Z)/2 ≤ R ≤ T1/2 + 0.3 defines the precise thickness needed for safety while maximizing the space available for active materials.
Solution Approach 2:
The patent applies the minimum necessary housing thickness T2 to achieve adequate safety performance. Rather than using excessive thickness that would reduce energy density, the formulas calculate the precise thickness required to accommodate the electrode assembly with appropriate clearance and stress distribution.
Data Source
Figure 1
Figure 2A~2B
Figure 3~4
AI summary
This application relates to a battery cell and an electronic device. A battery cell according to an embodiment includes: an electrode assembly and a housing. The electrode assembly possesses a thickness T1 in a thickness direction of the battery cell. The housing is configured to accommodate the electrode assembly, and possesses a thickness T2 in the thickness direction. The housing includes a first surface and a second surface; an arc-shaped first lateral edge, connected to the second surface and possessing a radius of R; a third surface, connected to the first lateral edge and configured to enclose at least a part of a lateral face of the electrode assembly; and a second lateral edge, including a first part and a second part. The first part extends away from the electrode assembly by starting from a first edge of the first surface and a second edge of the third surface. The second part extends toward the electrode assembly, and the second part possesses an ending edge connected to the third surface. Along the thickness direction, a plane in which the second edge of the third surface is located in the thickness direction is at a dimension Z apart from a plane in which the ending edge is located in the thickness direction, and (T2-Z)/2 ≤ R ≤ T1/2 + 0.3 mm.