Battery Stack Compression via Insulated Metal Bands
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Solution Overview
Problem
Existing battery systems with stacked rectangular batteries face issues such as increased internal resistance and potential short circuits due to battery expansion, which affects performance and safety, especially in lithium-ion batteries, and previous solutions like metal bands have difficulties in preventing short circuits and maintaining proper compression.
Innovation Solution
The battery system employs plastic insulating separators with integrated insulating walls that electrically isolate metal bands from battery cell outer walls, preventing short circuits while maintaining the metal bands in close proximity to the cells, and uses endplates and metal bands to compress the battery stack effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If metal bands are placed close to battery cell outer walls to maintain compression, then compression effectiveness is improved, but short circuit risk increases due to potential contact with battery external cases
Solution Approach 1:
An insulating separator made of plastic material is introduced as an intermediary component between the metal band and the battery cell outer wall. The separator includes an insulating plate section and insulating walls that extend to cover the outer wall of the battery cell, preventing direct contact between the conductive metal band and the battery external case, thereby eliminating the short circuit risk while maintaining compression effectiveness.
2Power
If lithium ion battery electrodes are made thin to reduce internal resistance, then power output is improved, but susceptibility to expansion damage increases
Solution Approach 1:
The insulating separator is installed in advance between the battery cell and the metal band to prevent harmful contact before it can occur. By pre-positioning this protective barrier, the system preemptively counteracts the potential expansion damage that could occur during battery operation, especially important for thin electrodes that are more vulnerable to expansion effects.
3Stability of the object's composition
If bolts are used to hold endplates together to maintain battery stack compression, then structural stability is improved, but deformation and short circuit risk increase due to bolt curvature during battery expansion
Solution Approach 1:
The insulating separator acts as a mediator between the metal band and battery cell, preventing direct contact. This eliminates the need for bolts that could deform and contact battery cells, as the flexible metal band with insulating separator provides both compression and electrical isolation, resolving the short circuit risk associated with bolt deformation.
Data Source
AI summary
A battery system has a battery block with a plurality of battery cells that are rectangular batteries stacked with intervening insulating separators, and that battery block is held by fastening components. The fastening components are provided with a pair of endplates disposed at the ends of the stacked battery cells, and metal bands on both sides of the battery block connected at both ends to the endplates. An insulating separator has an insulating plate section, which intervenes between adjacent battery cells, and insulating walls, which cover both battery cell side-walls, formed from plastic as a single-piece. In this battery system, insulating plate sections are sandwiched between battery cells, and the insulating walls are disposed between battery cell outer side-walls and metal bands to insulate the battery cells from the metal bands.