Battery Cell Insulation Geometry for Arc-Transition Short-Circuit Control
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Solution Overview
Problem
Lithium-ion batteries face significant safety risks due to internal short circuits, which can lead to excessive heat, fires, and electrical appliance damage, posing threats to property and life safety.
Innovation Solution
A battery cell design incorporating a casing with a specific circular arc transition surface, separated by first and second insulating members with partition portions and foldable parts, ensuring the electrode assembly is properly insulated from the casing walls and bottom, preventing short circuits and wrinkling of electrode plates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the electrode assembly is placed close to the bottom wall to maximize space utilization, then the volume efficiency is improved, but the risk of short circuit increases due to potential contact between the electrode plate and the bottom wall
Solution Approach 1:
The patent introduces an insulating member as an intermediary component between the electrode assembly and the bottom wall. This insulating member includes a bottom insulating portion that contacts the bottom wall and side insulating portions that extend upward to contact the electrode assembly, thereby preventing direct contact and potential short circuits while allowing the electrode assembly to be positioned close to the bottom wall for space efficiency.
2Volume of moving object
If the electrode assembly is positioned to maximize space utilization, then the volume efficiency is improved, but the electrode plate may interfere with the circular arc transition surface causing wrinkling and short circuit
Solution Approach 1:
The side insulating portions of the insulating member act as intermediaries between the electrode assembly and the circular arc transition surface. These portions prevent the electrode plate from contacting and wrinkling on the transition surface, maintaining electrode plate integrity while allowing close positioning for volume efficiency.
Solution Approach 2:
The insulating member is pre-installed on the bottom wall before placing the electrode assembly. The side insulating portions extend upward to create a protective barrier in advance, preventing potential interference between the electrode plate and the circular arc transition surface before the electrode assembly is positioned.
3Reliability
If insulating members are added to prevent short circuits and electrode interference, then the safety performance is improved, but the device complexity increases
Solution Approach 1:
The insulating member integrates multiple functions into a single component: the bottom insulating portion provides insulation from the bottom wall, while the side insulating portions provide insulation from the side walls and protect against circular arc transition surface interference. This merging reduces the need for multiple separate insulating components, thereby limiting the increase in structural complexity.
Solution Approach 2:
The insulating member serves multiple purposes simultaneously: it prevents short circuits between the electrode assembly and the bottom wall, protects against interference with the circular arc transition surface, and provides overall insulation support. This multi-functionality improves safety performance without requiring proportionally more complex structures.
Data Source
AI summary
A battery cell includes a casing, an electrode assembly, a first insulating member and a second insulating member. The inner surface of a bottom wall of the casing is connected to the inner surface of a first side wall by a first arc transition surface; a first partition portion of the first insulating member separates the electrode assembly and the first side wall; the second insulating member separates the electrode assembly and the bottom wall; in the thickness direction of the second insulating member, the separator of the electrode assembly has a stacked part located between an electrode plate and the second insulating member; and the radius R1 of the first circular arc transition surface, the thickness a1 of the first partition portion, the thickness b of the stacked part and the thickness c of the second insulating member satisfy R1≤(c+b)2+4(a1)2+[(a1)*(c+b)]1/2.