Secondary Battery Silicon Negative Electrode Capacity

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Solution Overview

Problem

Lithium nickel oxide-based positive electrode active materials in secondary batteries exhibit poor initial charge/discharge efficiency, leading to a large initial irreversible capacity, which necessitates a higher amount of negative electrode active material, reducing battery capacity.

Innovation Solution

Incorporating silicon, silicon oxide, or silicon alloys as negative electrode active materials, which have a higher irreversible capacity, allowing for a reduced amount of negative electrode material while maintaining or improving battery capacity, with the positive electrode active material comprising lithium nickel oxide.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If lithium nickel oxide is used as positive electrode active material, then cost is reduced and manganese content is increased, but initial charge/discharge efficiency deteriorates and irreversible capacity increases

Engineering Contradiction:

ImprovecostVSAvoidinitial charge/discharge efficiency

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The patent modifies the chemical composition parameters of lithium nickel oxide by adding manganese and cobalt elements to create LiNi0.8Co0.1Mn0.1O2 composite material. This parameter change resolves the contradiction by maintaining the cost advantage of high nickel content while improving initial charge/discharge efficiency through the synergistic effects of manganese and cobalt additions.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite material LiNi0.8Co0.1Mn0.1O2 that combines the advantages of nickel (high capacity), cobalt (high voltage and stability), and manganese (low cost and structural stability). This composite approach resolves the contradiction between cost reduction and efficiency maintenance by leveraging the complementary properties of different elements.

Inventive Principle:

Principle #40Composite materials

2Quantity of substance

If lithium nickel oxide with high irreversible capacity is used, then battery capacity is reduced due to need for larger negative electrode active material amount, but positive electrode performance is improved

Engineering Contradiction:

Improvebattery capacityVSAvoidirreversible capacity

Core Design Contradiction:

Quantity of substanceVSLoss of substance

Solution Approach 1:

The patent optimizes the ratio of positive to negative electrode active materials based on the irreversible capacity characteristics of lithium nickel oxide. By carefully adjusting this parameter, the patent minimizes the amount of negative electrode material needed while maximizing the utilization of positive electrode capacity, thereby resolving the contradiction between battery capacity and irreversible capacity loss.

Inventive Principle:

Principle #35Parameter changes

3Reliability

If larger amount of negative electrode active material is used, then irreversible capacity is compensated, but battery capacity is reduced

Engineering Contradiction:

Improveirreversible capacity compensationVSAvoidbattery capacity

Core Design Contradiction:

ReliabilityVSQuantity of substance

Solution Approach 1:

The patent applies partial action by using exactly the right amount of negative electrode active material needed to compensate for irreversible capacity losses, rather than using excessive amounts. This optimized approach ensures sufficient compensation while maximizing battery capacity, resolving the contradiction between reliability and quantity.

Inventive Principle:

Principle #16Partial or excessive action

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 configuration enhances battery capacity by allowing a smaller amount of negative electrode material, achieving a higher cell capacity and reducing lithium deposition on the cathode, while maintaining efficient charge/discharge characteristics.

Implementation Method 1

Each of the positive electrode plate and negative electrode plate includes a positive electrode active material and a negative electrode active material, which are capable of reversibly intercalating lithium ions.

Methodology Applied

Scientific EffectIntercalation: Absorption (physical)

Implementation Method 2

The positive electrode active material can include lithium cobalt oxide, lithium manganese oxide, lithium nickel oxide, or the like.

Methodology Applied

Scientific EffectIntercalation: Absorption (physical)

Data Source

PatentUS9450240B2Secondary battery

Publication Date: 2016.09.20 SAMSUNG SDI CO LTD

AI summary

A secondary battery including: an anode including a positive electrode active material; a cathode including a negative electrode active material; a separator interposed between the anode and the cathode; and a non-aqueous electrolyte. The positive electrode active material includes a lithium nickel oxide, and the negative electrode active material includes at least one silicon compound selected from the group consisting of silicon, a silicon oxide, and a silicon alloy.