Bipolar-Stacked Sulfide Solid-State Batteries With Shared Current Collectors
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Solution Overview
Problem
Current bipolar-stacked all-solid-state lithium batteries (ASLBs) based on polymer electrolytes face challenges such as low ionic conductivity, risk of ionic short circuits at high temperatures, and the need for reliable laminated electrodes and electrolyte layers, particularly with sulfide solid electrolytes.
Innovation Solution
The development of sulfide SE-based bipolar-stacked ASLBs with freestanding, robust, and flexible cathode, sulfide solid electrolyte, and anode layers, fabricated through a vacuum filtration method using an ethyl cellulose-toluene system, which enables high ionic conductivity and thermal stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If polymer electrolytes are used in bipolar-stacked ASLBs, then ease of manufacture is improved, but ionic conductivity is limited and thermal stability deteriorates causing ionic short circuits at high temperatures
Solution Approach 1:
The patent changes the material parameter from polymer electrolyte to sulfide solid electrolyte, fundamentally altering the ionic conductivity and thermal stability characteristics. This material substitution enables high ionic conductivity (>1 mS cm−1) and high thermal stability while maintaining compatibility with bipolar stacking through optimized electrode and electrolyte layer fabrication parameters
Solution Approach 2:
The patent employs composite material design by creating integrated electrode-electrolyte layers where sulfide solid electrolyte is combined with cathode and anode materials in a laminated structure. This composite approach ensures good film formability and mechanical strength while achieving the desired ionic conductivity and thermal stability for bipolar-stacked ASLBs
2Reliability
If conventional separate cell packing is used, then reliability is improved by avoiding internal ionic short circuits, but usage of inactive materials increases significantly limiting energy density
Solution Approach 1:
The patent merges multiple cell functions into a single bipolar-stacked structure where adjacent cathode and anode share one current collector. This consolidation eliminates the need for separate sealing and packing materials between individual cells, significantly reducing inactive material usage while the solid electrolyte prevents internal ionic short circuits, thereby achieving both high reliability and high energy density (204 Wh kg-1)
3Reliability
If sulfide SE-based bipolar-stacked ASLBs are fabricated, then ionic conductivity and thermal stability are improved, but manufacturing complexity increases due to need for compatible electrodes and SE layers with good film formability
Solution Approach 1:
The patent optimizes fabrication parameters including vacuum filtration conditions, drying temperature, and pressing pressure to achieve uniform thin films of sulfide solid electrolyte and electrode layers. By controlling these parameters, the patent achieves good film formability and mechanical strength, reducing manufacturing complexity while maintaining high ionic conductivity and thermal stability
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
This approach results in high voltage and high energy density bipolar-stacked ASLBs, with a cell-level energy density of 204 Wh kg-1, surpassing conventional stacking methods, and facilitates the commercialization of sulfide SE-based ASLBs in large-scale manufacturing.
Implementation Method 1
Given the high ionic conductivity (>1 mS cm−1) and high thermal stability, sulfide SEs are one of the best candidates to fabricate bipolar-stacked ASLBs
Implementation Method 2
fabricated through a vacuum filtration method using an ethyl cellulose-toluene system
Implementation Method 3
fabricated through a vacuum filtration method using an ethyl cellulose-toluene system
Implementation Method 4
adjacent mono cells are connected through a single, shared current collector in contact with a cathode and an anode of adjacent mono cells
Data Source
AI summary
Described herein is an all-solid-state battery comprising two or more mono cells connected in series, wherein: each mono cell comprises a lithium-based cathode, a sulfide solid electrolyte, and an anode; and adjacent mono cells are connected through a single, shared current collector in contact with a cathode and an anode of adjacent mono cells. The all-solid-state battery can be fabricated by stacking freestanding layers of the lithium-based cathode, the sulfide solid electrolyte, the anode, and the current collector in a bipolar design, and pressing the layers together to form the all-solid-state battery. The lithium-ion battery -can be incorporated into portable electronics and electric vehicles.