Non-aqueous Electrolyte Secondary Battery Low-Temperature Resistance
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Solution Overview
Problem
Non-aqueous electrolyte secondary batteries face increased internal resistance when used at low temperatures after being exposed to high temperatures, which affects their output characteristics, and existing additives like ionic metal complexes and cyclic sulfate esters have not adequately addressed this issue.
Innovation Solution
Incorporating a non-aqueous electrolyte with 1.0 wt% or less of a specific compound and 2.0 wt% or less of a cyclic sulfate ester, such as pentylene glycol sulfate, into the battery formulation to inhibit the increase in internal resistance when used at low temperatures after storage at high temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the battery is used at low temperature after storage at high temperature, then the internal resistance increases, but the output characteristics deteriorate
Solution Approach 1:
The patent changes the chemical composition parameters of the electrolyte by adding specific additives (cyclic sulfate ester and ionic metal complex) to modify the electrolyte's properties. This resolves the contradiction by creating an electrolyte formulation that maintains stable internal resistance across temperature variations, thereby preserving output characteristics even when transitioning from high to low temperature storage conditions
Solution Approach 2:
The patent creates a composite electrolyte system by combining multiple components: cyclic carbonate, chain carbonate, cyclic sulfate ester, and ionic metal complex. This composite electrolyte formulation works synergistically to prevent internal resistance increase during temperature transitions, thus maintaining both reliability and power output characteristics under varying temperature conditions
2Temperature
If high temperature storage is performed, then the internal resistance increases, but the battery performance under low temperature conditions deteriorates
Solution Approach 1:
The patent applies preliminary action by adding cyclic sulfate ester and ionic metal complex additives to the electrolyte before the battery undergoes high-temperature storage. These additives pre-form protective films or stabilize the electrolyte composition in advance, preventing internal resistance increase during subsequent high-temperature exposure and maintaining reliability under low-temperature operating conditions
Solution Approach 2:
The patent implements beforehand cushioning by incorporating additives that cushion or buffer the electrolyte against temperature-induced degradation. The cyclic sulfate ester and ionic metal complex act as protective agents that mitigate the harmful effects of high-temperature storage on internal resistance, ensuring stable performance when the battery transitions to low-temperature operation
Data Source
Figure 1
AI summary
A non-aqueous electrolyte secondary battery includes a positive electrode containing a positive-electrode active material, a negative electrode containing a negative-electrode active material, and a non-aqueous electrolyte, and is characterized in that the non-aqueous electrolyte contains 1.0 wt% or less of a compound represented by formula (1) and 2.0 wt% or less of a cyclic sulfate ester represented by formula (2), based on the total weight of the non-aqueous electrolyte. By using the non-aqueous electrolyte including a specified amount of the compound represented by formula (1) and a specified amount of the cyclic sulfate ester, when ihe battery is used at a low temperature after being stored at a high temperature, the increase of the internal resistance is inhibited.