Segmented Mandrel for Compact Jelly Roll Battery Assembly
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Solution Overview
Problem
Existing battery technologies face challenges in achieving compactness while maintaining high power output and reliability, as the removal of the mandrel from jelly roll batteries can damage the assembly and result in reduced capacity due to the need for loose wrapping to avoid damage, leading to inefficiencies in space utilization and power storage.
Innovation Solution
A mandrel with a positive and negative portion and removable portions, featuring a passage between them, allows for conductive connection of electrodes and feedthrough pins, enabling secure wrapping and heat sealing of separators to create a compact jelly roll electrode assembly without the need for extraneous tabs, thereby enhancing battery compactness and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the mandrel is removed from the core of the jelly roll, then the mandrel can be reused and production cost can be reduced, but the jelly roll may be damaged due to pulling the core out
Solution Approach 1:
The mandrel is divided into two separate portions: a conductive mandrel portion that remains integrated with the jelly roll assembly and a removable non-conductive portion that can be detached and reused. This segmentation allows the removable portion to be taken out without damaging the conductive mandrel portion or the jelly roll, resolving the contradiction between mandrel reusability and jelly roll integrity.
2Quantity of substance
If the jelly roll is wrapped tightly to eliminate dead space, then battery capacity and power are increased, but the mandrel removal becomes more difficult and may cause damage
Solution Approach 1:
By segmenting the mandrel into conductive and removable non-conductive portions, the jelly roll can be wrapped tightly around the conductive mandrel portion to maximize capacity, while the removable non-conductive portion can be easily detached without compromising the tight wrapping or causing damage to the assembly.
3Stability of the object's composition
If a non-conductive mandrel is used to prevent deformation, then the jelly roll structure is stabilized, but current conduction requires additional conductive tabs which increase complexity
Solution Approach 1:
The conductive mandrel portion serves multiple functions: it provides structural support to prevent deformation during assembly, acts as a current conduction path eliminating the need for separate conductive tabs, and remains integrated with the jelly roll assembly. This multi-functionality reduces device complexity while maintaining structural stability.
4Device complexity
If the mandrel is made conductive to eliminate tabs, then device complexity is reduced, but the mandrel cannot be removed and reused
Solution Approach 1:
The mandrel is segmented into a conductive portion that remains for current conduction and structural support, and a removable non-conductive portion that can be detached and reused. This segmentation allows the system to benefit from both conductive mandrel advantages (reduced complexity) and removable mandrel advantages (reusability).
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution enables the creation of a compact battery with improved power storage and reliability by allowing for secure wrapping and efficient use of space, reducing the risk of damage during assembly and eliminating the need for additional tabs, thus enhancing the battery's performance and longevity.
Implementation Method 1
The jelly roll assembly can be secured by heat sealing one or more protruding ends of the one or more separators to each other or to an underlying separator layer
Data Source
AI summary
Provided is an electric storage battery including a jelly roll type electrode assembly having a mandrel. The mandrel includes a positive portion, a negative portion and a removable portion. In some embodiments, the mandrel is planar having two faces with a groove on each of the positive and negative portions. The grooves can be on the same or different faces of the mandrel. The grooves are dimensioned to accommodate a positive and negative feedthrough pin. The electrodes are wrapped around the mandrel using the removable portion to wind the mandrel. Once wrapped, the removable portion can be detached. The positive portion and the negative portion are left in the electrode assembly insulated from each other. The mandrel allows tighter wrapping of the jelly roll assembly, increasing battery miniaturization and also results in electrode assemblies in which after-placement of tabs does not result in burrs or shorting.