Positive Electrode Layer Length for High-Capacity Li-Ion Output
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Solution Overview
Problem
Lithium-ion secondary batteries lack high capacity and high output, with existing technologies not adequately addressing the relationship between the length of the positive electrode active material layer and battery performance.
Innovation Solution
A lithium-ion secondary battery design featuring a positive electrode active material layer with a specific composition (LixNiyCozM1-y-zO2) and a length of 300 mm to 740 mm, optimizing the battery's capacity and output.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the positive electrode active material layer length is increased to improve capacity, then the battery capacity increases, but the output may be compromised due to increased internal resistance
Solution Approach 1:
The patent applies parameter changes by optimizing the length of the positive electrode active material layer to a specific range (300-740 mm) and controlling the nickel composition ratio (0.80≤y≤0.93) in the LixNiyCozM1-y-zO2 material. This specific parameter combination resolves the contradiction by achieving both high capacity and high output, as the optimized length and composition balance the trade-off between capacity accumulation and output performance.
2Quantity of substance
If high nickel content (y≥0.80) is used to improve capacity, then the battery capacity increases, but thermal stability deteriorates
Solution Approach 1:
The patent uses composite materials by employing LixNiyCozM1-y-zO2 where M contains at least one element from Mn and Al. The high nickel content (y≥0.80) provides high capacity, while the cobalt, manganese, and aluminum elements contribute to thermal stability. This composite approach allows the battery to achieve both high capacity and adequate thermal stability simultaneously.
Solution Approach 2:
The patent controls the nickel composition ratio within a specific range (0.80≤y≤0.93) rather than using maximum nickel content. This parameter optimization balances capacity improvement with thermal stability maintenance, as excessive nickel content would compromise thermal stability while the specified range achieves the desired capacity with acceptable thermal performance.
Data Source
AI summary
A positive electrode (100) includes a first positive electrode active material layer (122) containing a positive electrode active material expressed by a general formula LixNiyCozM1-y-zO2 (where 0.80≤y≤0.93, and M denotes a metallic element containing at least one element out of Mn and Al). The length of the first positive electrode active material layer (122) in a longitudinal direction is equal to or greater than 300 mm and equal to or less than 740 mm.