Lithium Primary Battery Alloy Anode for Uniform Lithium Consumption
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Solution Overview
Problem
Lithium is nonuniformly consumed in the negative electrode of lithium primary batteries, leading to local consumption issues and potential chipping or fracture, which isolates lithium and causes performance deterioration.
Innovation Solution
A lithium primary battery design with a wound electrode group configuration, where the negative electrode contains a lithium alloy with 0.02% to 11% magnesium by mass, and the facing area of the negative electrode principal surfaces with the positive electrode is 90% or more, ensuring uniform lithium consumption and improved electrode connectivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If lithium is used as the negative electrode active material, then high energy density is achieved, but nonuniform lithium consumption causes local chipping or fracture leading to lithium isolation
Solution Approach 1:
The negative electrode uses a lithium alloy containing magnesium (0.02-11% by mass) instead of pure lithium. This composite material approach combines lithium's high energy density with magnesium's structural stability, preventing the chipping and fracture that occurs with pure lithium while maintaining excellent energy density.
Solution Approach 2:
The invention changes the compositional parameter of the negative electrode from pure lithium to a lithium alloy with controlled magnesium content (0.02-11% by mass). This parameter change fundamentally alters the electrochemical behavior, enabling uniform lithium consumption and preventing electrode degradation while preserving high energy density.
2Speed
If the negative electrode is made thinner to reduce internal resistance, then pulse discharge characteristics improve, but lithium consumption becomes more nonuniform causing fracture
Solution Approach 1:
The lithium alloy with magnesium creates a more uniform electrochemical reaction distribution throughout the electrode thickness. The magnesium forms an alloy structure that promotes uniform lithium extraction and insertion, preventing localized stress concentration even in thin electrodes, thus enabling both high pulse discharge rates and uniform lithium consumption.
3Strength
If magnesium content in lithium alloy is increased to improve structural stability, then electrode fracture is prevented, but energy density decreases
Solution Approach 1:
The invention optimizes the magnesium content parameter within a specific range (0.02-11% by mass). Below 0.02%, the structural stability effect is insufficient; above 11%, the energy density penalty becomes too large. This precise parameter control achieves the optimal balance between electrode strength and energy density.
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 design suppresses lithium isolation and maintains electrode conductivity, enhancing battery performance and output characteristics, particularly in pulse discharge scenarios.
Implementation Method 1
a negative electrode containing a lithium alloy and a nonaqueous electrolyte
Implementation Method 2
ensuring uniform lithium consumption and improved electrode connectivity
Data Source
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AI summary
A lithium primary battery includes an electrode group and a nonaqueous electrolyte. The electrode group is configured by spirally winding a band-shaped positive electrode and a band-shaped negative electrode with a separator therebetween. The positive electrode contains at least one selected from the group consisting of manganese dioxide and graphite fluoride. The negative electrode contains a lithium alloy. The lithium alloy contains Mg in an amount of 0.02% by mass or more and 11% by mass or less. The negative electrode has a first negative electrode principal surface on the outer peripheral side of the electrode group and a second negative electrode principal surface on the inner peripheral side of the electrode group. The positive electrode has a first positive electrode principal surface on the inner peripheral side of the electrode group and a second positive principal surface on the outer peripheral side of the electrode group. The first negative electrode principal surface has a first facing region facing the first positive electrode principal surface. The second negative electrode principal surface has a second facing region facing the second positive electrode principal surface. The proportion of the total area S1 of the first facing region and the second facing region to the total area S0 of the first negative electrode principal surface and the second negative electrode principal surface is 90% or more.