Multi-Layer Positive Electrode Electrolyte Tuning for High-Temperature Cells
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Solution Overview
Problem
Existing lithium secondary batteries face challenges in achieving high-temperature performance due to uniform electrolyte composition across varying electrode layers, leading to increased side reactions and resistance, despite differing requirements for each layer.
Innovation Solution
A multi-layer positive electrode structure is implemented, with varying nickel contents in lithium composite transition metal oxides, where one layer includes an electrolyte additive and the other does not, optimizing electrolyte components for each layer to minimize side reactions and resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a uniform electrolyte composition is used across all electrode layers, then the manufacturing process is simple, but side reactions increase and high-temperature performance deteriorates
Solution Approach 1:
The patent applies different electrolyte compositions to different electrode layers based on their specific requirements. The first electrode layer uses an electrolyte with a first composition, while the second electrode layer uses an electrolyte with a second composition. This local differentiation allows each layer to operate under optimal electrolyte conditions, reducing side reactions and improving high-temperature performance without complicating the overall manufacturing process.
2Reliability
If electrolyte additives are added to all electrode layers, then battery performance is improved, but gas generation increases and resistance increases
Solution Approach 1:
The patent selectively adds electrolyte additives only to specific electrode layers where they are most beneficial. The first electrolyte contains a first additive while the second electrolyte contains a second additive, with the composition tailored to each layer's characteristics. This localized approach improves battery performance where needed while minimizing gas generation and resistance increases that would occur with universal additive application.
3Reliability
If unnecessarily large amounts of solvent and electrolyte additive are used, then desired battery performance is achieved, but side reactions increase and cost increases
Solution Approach 1:
The patent optimizes the concentration and composition parameters of electrolytes and additives for each specific electrode layer. Instead of using unnecessarily large amounts of solvent and additive across all layers, the electrolyte composition is precisely tuned for each layer's requirements. This parameter optimization achieves desired battery performance while minimizing side reactions and reducing material costs.
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 enhances high-temperature performance, reduces gas generation, and minimizes resistance in lithium secondary batteries by tailoring electrolyte additives to specific electrode layers.
Implementation Method 1
Lithium secondary batteries generate electrical energy through oxidation and reduction reactions when lithium ions are intercalated/deintercalated into/from a positive electrode and a negative electrode
Data Source
AI summary
Provided is a positive electrode for a secondary battery, which has a multi-layer structure including a first positive electrode active material layer and a second positive electrode active material layer, wherein the first positive electrode active material layer includes a first lithium composite transition metal oxide containing nickel, cobalt, and manganese, the second positive electrode active material layer includes a second lithium composite transition metal oxide containing nickel, cobalt, and manganese, the first lithium composite transition metal oxide and the second lithium composite transition metal oxide have mutually different nickel contents, wherein the positive electrode active material layer including a lithium composite transition metal oxide having a relatively high nickel content includes an electrolyte additive, and the positive electrode active material layer including a lithium composite transition metal oxide having a relatively low nickel content does not include an electrolyte additive.