Non-Aqueous Battery Electrolyte Composition for Low-Temperature Output
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Solution Overview
Problem
Non-aqueous electrolyte secondary batteries used for drive power sources in vehicles face challenges in maintaining excellent battery characteristics, particularly in low-temperature environments, with issues of lithium precipitation and hindered ion movement.
Innovation Solution
The battery design includes a non-aqueous electrolyte solution with specific solvent ratios of chain and cyclic carbonates, the use of carboxymethyl cellulose in the negative electrode active material layer, and a flat wound electrode assembly configuration, along with a polyolefin separator, to enhance lithium ion mobility and suppress precipitation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional electrolyte compositions are used, then the battery can operate at room temperature, but the battery characteristics deteriorate in low-temperature environments
Solution Approach 1:
The patent applies parameter changes by optimizing the composition ratios of electrolyte solvents. Specifically, it uses a mixed solvent system comprising cyclic carbonate (15-30 vol%), chain carbonate (65-80 vol%), and chain carboxylate (1-10 vol%), which changes the physical and chemical parameters of the electrolyte to maintain low viscosity and high ionic conductivity at low temperatures, thereby improving battery characteristics in cold environments
Solution Approach 2:
The patent employs composite materials by creating a multi-component electrolyte system that combines different types of carbonates and carboxylates. This composite electrolyte composition leverages the complementary properties of each component: cyclic carbonate provides high dielectric constant, chain carbonate provides low viscosity, and chain carboxylate provides low freezing point, achieving synergistic effect that maintains reliable battery operation at low temperatures
2Power
If the electrolyte is designed for low-temperature operation, then output characteristics improve, but lithium precipitation occurs more easily
Solution Approach 1:
The patent uses parameter changes by adjusting the electrolyte composition to achieve optimal viscosity and ionic conductivity. The specific formulation with chain carboxylate (1-10 vol%) and chain carbonate (65-80 vol%) creates an electrolyte with balanced properties that enables high power output at low temperatures while preventing lithium precipitation through controlled solvation and reduced nucleation sites
Solution Approach 2:
The patent introduces chain carboxylate as an intermediary substance that mediates between the conflicting requirements of low-temperature performance and lithium precipitation prevention. The chain carboxylate molecules act as intermediaries that facilitate lithium ion transport while their molecular structure prevents excessive solvation that would lead to precipitation, thus resolving the contradiction between power output and precipitation resistance
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 results in improved low-temperature output characteristics and reduced lithium precipitation, ensuring effective battery performance in cold conditions.
Implementation Method 1
the non-aqueous electrolyte solution includes a non-aqueous solvent, the non-aqueous solvent includes 50 to 80% by volume of a chain carbonate based on the non-aqueous solvent
Implementation Method 2
the above configuration allows the non-aqueous electrolyte solution to be less likely to be frozen more effectively by including propylene carbonate and methyl propionate with low freezing points
Data Source
Figure 1~3(b)
Figure 4(a)~4(b)
AI summary
Provided is a non-aqueous electrolyte secondary battery having excellent properties even at low temperatures. The non-aqueous electrolyte secondary battery comprises: an electrode assembly including a positive electrode plate and a negative electrode plate; a non-aqueous electrolyte; an exterior body having an opening, and accommodating the electrode assembly and the non-aqueous electrolyte; and a sealing plate for sealing the opening of the exterior body, wherein the negative electrode plate has a negative electrode core and a negative electrode active material layer formed on the negative electrode core, and the non-aqueous electrolyte contains a non-aqueous solvent, the non-aqueous solvent containing 50-80 vol% of a chain carbonate with respect to the non-aqueous solvent, and containing, as the chain carbonate, 30-40 vol% of dimethyl carbonate, 3-8 vol% of propylene carbonate, and 2-5 vol% of methyl propionate with respect to the non-aqueous solvent.