Positive Electrode Plate Layout for Battery Temperature Gradients
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Solution Overview
Problem
Secondary batteries, particularly lithium/sodium ion batteries, experience irreversible lithium ion depletion and material destruction due to temperature gradients within the battery, leading to reduced cycle life and performance.
Innovation Solution
A positive electrode plate design with distinct regions, where a first alkali metal ion-providing material with irreversible capacity and a second alkali metal ion-providing material with reversible capacity are distributed in specific areas to compensate for capacity loss and electrochemical activity variations, ensuring improved cycle life by optimizing alkali metal ion distribution and porosity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a uniform positive electrode film is used throughout the battery, then the manufacturing process is simple, but the battery experiences uneven temperature distribution and irreversible lithium ion depletion in high-temperature regions
Solution Approach 1:
The patent applies local quality by differentiating the positive electrode film into two types: a first positive electrode film with higher lithium ion conductivity placed in high-temperature regions (waist/center), and a second positive electrode film with lower lithium ion conductivity placed in low-temperature regions (ends/edges). This local differentiation addresses the uneven temperature distribution and prevents irreversible lithium ion depletion in high-temperature regions while maintaining overall battery reliability.
2Reliability
If the first positive electrode film with high lithium ion conductivity is used in high-temperature regions, then irreversible lithium ion depletion is reduced, but the device complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the positive electrode into multiple regions (high-temperature regions and low-temperature regions) and assigning different positive electrode film types to each region. The first positive electrode film is placed in high-temperature regions (waist/center) while the second positive electrode film is placed in low-temperature regions (ends/edges), creating a segmented structure that addresses reliability issues without excessive complexity.
3Reliability
If alkali metal ion-providing materials are distributed to compensate for irreversible capacity loss, then cycle life is improved, but the manufacturing precision requirements increase
Solution Approach 1:
The patent applies local quality by distributing alkali metal ion-providing materials specifically in the first positive electrode film located in high-temperature regions where irreversible lithium ion depletion occurs. This localized material distribution compensates for capacity loss in critical regions without requiring precise uniform distribution throughout the entire electrode, thereby improving cycle life while managing manufacturing precision requirements.
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 solution enhances the cycle life of secondary batteries by effectively managing alkali metal ion distribution and porosity, reducing the risk of short-circuiting and maintaining performance across temperature gradients.
Implementation Method 1
the first alkali metal ion-providing material of the first positive electrode film has an irreversible capacity
Implementation Method 2
the second alkali metal ion-providing material of the first positive electrode film has a reversible capacity
Implementation Method 3
the temperature at a cell waist is higher than the temperature at an end when a battery is operating; for a laminated cell, the temperature at a center portion of the cell is higher than the temperature at an edge portion of the cell
Implementation Method 4
Regions with higher temperatures exhibit higher electrochemical activity than regions with lower temperatures. The regions of high electrochemical activity have a higher rate of lithium ion depletion
Data Source
AI summary
Provided is a positive electrode plate, a secondary battery, and a powered device. The positive electrode plate may be a positive electrode plate of a wound cell, and includes a waist region provided close to a waist portion and an end region provided away from the waist portion. The waist region is provided with a first positive electrode film, and the end region is provided with a second positive electrode film. The positive electrode plate may be a positive electrode plate for a laminated cell, which includes a central region provided close to a center and an edge region provided away from the center. The central region is provided with a first positive electrode film, and the edge region is provided with a second positive electrode film.