Composite Positive Electrode Material for Hybrid Battery Power
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Solution Overview
Problem
Non-aqueous electrolyte secondary batteries using lithium-containing nickel-manganese oxides exhibit low discharge capacity and poor power characteristics due to high resistance, making them unsuitable for hybrid automobiles, which require uniform power characteristics over a wide range of charge depth.
Innovation Solution
A non-aqueous electrolyte secondary battery is developed using a positive electrode active material comprising a mixture of lithium-containing transition metal oxides with specific crystal structures and compositions, including a combination of lithium-containing nickel-manganese oxide and lithium-containing nickel-manganese-cobalt oxide, or lithium cobalt oxide, to enhance power characteristics and achieve uniform power delivery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If lithium-containing nickel-manganese oxide is used as positive electrode active material, then cost is reduced compared to lithium cobalt oxide, but discharge capacity and power characteristics deteriorate due to high resistance
Solution Approach 1:
The patent uses a composite positive electrode active material consisting of lithium-containing nickel-manganese oxide and lithium-containing nickel-manganese-cobalt oxide. This composite structure combines the cost advantage of nickel-manganese oxide with the superior electrical conductivity and power characteristics of nickel-manganese-cobalt oxide, thereby resolving the contradiction between cost reduction and power characteristic deterioration.
2Reliability
If lithium-containing nickel-manganese-cobalt oxide is used to improve power characteristics, then resistance is reduced, but uniform power characteristics over wide charge depth range deteriorate
Solution Approach 1:
The patent applies local quality by creating a composite material where different components serve different functions: lithium-containing nickel-manganese oxide provides cost effectiveness and structural stability, while lithium-containing nickel-manganese-cobalt oxide provides enhanced electrical conductivity and power characteristics. The specific composition ratio (0.01≤c≤0.5) is optimized to achieve both improved power characteristics and uniform performance across wide charge depth ranges.
3Temperature
If lithium-manganese composite oxide with spinel structure is used to improve low-temperature power characteristics, then low-temperature performance is enhanced, but power characteristics and battery capacity become insufficient
Solution Approach 1:
The patent changes the compositional parameters by incorporating cobalt into the nickel-manganese oxide structure to form lithium-containing nickel-manganese-cobalt oxide. This compositional modification fundamentally alters the electrical conductivity and electrochemical properties, providing superior power characteristics and capacity compared to conventional lithium-manganese spinel oxides, while maintaining structural stability across temperature ranges.
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 battery achieves dramatic improvements in power characteristics and uniformity over a wide range of charge depth, simplifying control algorithms and reducing system costs for hybrid automobiles.
Implementation Method 1
a non-aqueous electrolyte having lithium ion conductivity
Data Source
AI summary
A non-aqueous electrolyte secondary battery uses as its positive electrode active material a mixture of a first lithium-containing transition metal oxide containing nickel and manganese as transition metals and having a crystal structure belonging to the space group R3m and a second lithium-containing transition metal oxide containing nickel, cobalt, and manganese as transition metals and having a crystal structure belonging to the space group R3m, or a mixture of the first lithium-containing transition metal oxide and a lithium cobalt oxide. The first lithium-containing transition metal oxide is LiaNixMnyO2 wherein 1≦a≦1.5, 0.5≦x+y≦1, 0<x<1, and 0<y<1. The second lithium-containing transition metal oxide is LibNipMnqCorO2 wherein 1≦b≦1.5, 0.5≦p+q+r≦1, 0<p<1, 0<q<1, and 0<r<1.