Lithium-Ion Electrode Pore Structure for High-Rate Cycle Life
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Solution Overview
Problem
Existing lithium ion batteries for hybrid electric vehicles (HEVs) lack the necessary high-rate charging-discharging capacity and service life, failing to meet the energy demands of HEVs.
Innovation Solution
A lithium ion battery design with optimized electrode structures, featuring specific surface areas of macro-pores and micro-mesopores, compacted densities, and material compositions for the positive and negative electrodes, including active materials, conductive agents, and adhesives, which enhance lithium ion transmission and electrolyte retention.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If existing lithium ion battery structures are used, then the battery can provide basic power supply, but the high-rate charging-discharging capacity is insufficient
Solution Approach 1:
The patent applies porous materials by constructing electrode pieces with dual pore structures (macro-pores and micro-mesopores). The macro-pores provide fast ion transport channels for high-rate charging-discharging, while the micro-mesopores offer sufficient surface area for electrochemical reactions. This porous structure design enables the battery to achieve both high power output and long cycle life by optimizing ion transmission efficiency and electrochemical activity simultaneously.
Solution Approach 2:
The patent implements local quality by creating different pore size distributions in different regions of the electrode structure. The electrode pieces contain both macro-pores (3.0-7.0 m2/g specific surface area) for fast ion transport and micro-mesopores (2.0-5.0 m2/g specific surface area) for electrochemical reactions. This local differentiation of pore qualities within the same electrode enables simultaneous optimization of power performance and cycle stability.
2Quantity of substance
If electrode material density is increased to improve energy density, then more lithium ions can be stored, but ion transmission speed decreases
Solution Approach 1:
The patent applies segmentation by dividing the electrode pore structure into two distinct segments: macro-pores for fast ion transmission and micro-mesopores for lithium ion storage and electrochemical reactions. This segmentation allows the electrode to simultaneously achieve high ion transmission speed through macro-pores and high lithium ion storage capacity through micro-mesopores, resolving the contradiction between speed and quantity.
Solution Approach 2:
The patent transitions from a single-pore-size structure to a dual-pore-size structure by adding another dimension of pore size classification. This dimensional change in pore structure design enables the electrode to accommodate both fast ion transport requirements (macro-pores) and high capacity requirements (micro-mesopores) without compromise.
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 excellent charging-discharging performance and extended service life under high-rate charging-discharging cycles by optimizing pore structures and material distributions, ensuring better energy density and stability.
Implementation Method 1
the macro-pores provide a main path for lithium ion transmission in the coating layer
Implementation Method 2
the electrolyte has a better liquid retention effect in it
Implementation Method 3
Lithium ion batteries have outstanding advantages such as high energy density, long cycle life, high working voltage
Data Source
AI summary
Disclosed is a lithium ion battery. The lithium ion battery comprises: a positive electrode piece, comprising a positive electrode coating area and a positive electrode empty foil area, herein the positive electrode coating area has macro-pores and micro-mesopores, the specific surface area of the macro-pores of the positive electrode coating area is 3.0˜7.0 m2/g, and the specific surface area of the micro-mesopores of the positive electrode coating is 2˜5 m2/g; and a negative electrode piece, comprising a negative electrode coating area and a negative electrode empty foil area, herein the negative electrode coating area has macro-pores and micro-mesopores, the specific surface area of the macro-pores of the positive electrode coating area is 0.8˜2.0 m2/g, and the specific surface area of the micro-mesopores of the positive electrode coating is 0.6˜1.7 m2/g. Compared with existing technologies, the lithium ion battery of the present disclosure has excellent rate performance, and may meet the requirements of long service life and high power of hybrid electric vehicles (HEV).