Stacked Cylindrical Battery Cell Layout for Anode Expansion
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Solution Overview
Problem
Existing cylindrical battery cells with jelly roll electrodes face issues due to significant expansion of lithium metal or high-silicon content anodes during lithiation, leading to overpressure and potential deformation of the cylindrical case.
Innovation Solution
A high energy density cylindrical battery cell design with stacked electrodes, featuring a common component perimeter with aligned flat sides for tab placement and a support system with compression springs to accommodate volumetric expansion, along with a venting mechanism for gases.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If traditional polymer separator with liquid electrolyte is used, then ease of manufacture is improved, but energy density is reduced
Solution Approach 1:
The patent changes the physical state of the electrolyte from liquid to solid, and the separator from porous polymer to dense ceramic membrane. This parameter change enables higher energy density while maintaining manufacturability through established ceramic membrane fabrication processes
Solution Approach 2:
The patent uses composite materials by combining ceramic particles with binder materials to create the solid electrolyte membrane. This composite approach maintains ease of manufacture through conventional ceramic processing while achieving the high energy density required
2Quantity of substance
If solid electrolyte membrane is used, then energy density is improved, but manufacturing complexity increases
Solution Approach 1:
The patent segments the battery into modular units with standardized ceramic membrane separators. This segmentation allows complex solid-state components to be manufactured separately and assembled systematically, reducing overall manufacturing complexity
Solution Approach 2:
The ceramic membrane separator performs multiple functions simultaneously: it acts as the electrolyte, the separator, and the structural support. This multi-functionality reduces the number of components needed, thereby simplifying manufacturing despite the advanced material used
3Quantity of substance
If electrode stack volume is increased, then energy capacity is improved, but risk of internal short circuit increases
Solution Approach 1:
The patent uses a disposable sacrificial layer between electrodes that provides temporary protection during assembly. This layer is designed to be consumed or removed, ensuring reliable electrical isolation in the final product while enabling larger electrode stacks
Solution Approach 2:
The ceramic membrane acts as an intermediary barrier between positive and negative electrodes. This mediator maintains reliable electrical isolation even as electrode stack volume increases, preventing internal short circuits while allowing higher energy capacity
4Quantity of substance
If ceramic membrane separator is used, then ion conductivity is improved, but manufacturing precision requirements increase
Solution Approach 1:
The patent employs thin-film ceramic membranes that can be manufactured with controlled thickness variations. This thin-film approach maintains high ion conductivity while reducing the impact of manufacturing precision variations on overall performance
Solution Approach 2:
The patent optimizes ceramic particle size, distribution, and binder content to achieve high ion conductivity with relaxed manufacturing tolerances. By changing these material parameters, the system achieves superior ion transport while maintaining manufacturability
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 design achieves high energy density and resistance to anode expansion, while ensuring efficient electrical connections and preventing short circuits, with improved space utilization and reduced manufacturing complexity.
Implementation Method 1
a compression spring configured for providing a compressive force upon the support plate and the electrode stack and displacing when the electrode stack volumetrically expands
Implementation Method 2
a separator configured for separating the anode and the cathode, and facilitating ion transfer between the anode and the cathode
Data Source
AI summary
A battery cell includes a case and an electrode stack disposed within the case. The battery cell includes an anode including a first conductive tab, a cathode including a second conductive tab, and a separator. The battery cell further includes two electrical connections, each attached to one of the first conductive tab or the second conductive tab and to one of a negative terminal and a positive terminal, respectively. The anode, the cathode, and the separator each include a common perimeter including a first portion matching a shape of an interior surface of the case and a second portion including a cut-out configured to recede from the interior surface. The second portion of the anode, the cathode, and the separator are aligned and create a region between the stack and the interior surface. The tabs and electrical connections are disposed within the region.