Secondary Battery Electrolyte Composition for Low-Temperature Charging
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Solution Overview
Problem
Lithium-ion batteries face safety issues due to lithium precipitation during low-temperature charging, which can lead to battery swelling and burning, limiting their use in certain environments.
Innovation Solution
Incorporating specific compounds into the electrolyte and adjusting the contact angle between the electrolyte and the separator's porous coating to enhance lithium ion transport, along with optimizing the composition and properties of the separator and electrolyte components, such as mass percentages and polymerization monomers, to improve kinetic and cycling performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If lithium-ion batteries are charged in low-temperature environment, then charging can be performed, but lithium precipitation occurs on the negative electrode plate leading to safety risks
Solution Approach 1:
The patent modifies the chemical composition parameters of the electrolyte by introducing compound A with specific molecular structure (formula I) and controlling its mass percentage (20-82%). This parameter change in electrolyte composition alters the physical-chemical properties of the electrolyte system, enabling effective lithium ion transport at low temperatures while preventing lithium precipitation on the negative electrode plate.
Solution Approach 2:
The patent creates a composite electrolyte system by combining compound A (formula I) with traditional electrolyte components. This composite electrolyte formulation synergistically combines the low-temperature performance enhancement from compound A with the stable ion conduction properties of conventional electrolytes, achieving both low-temperature charging capability and prevention of lithium precipitation.
2Speed
If compound A is added to electrolyte to improve lithium ion transport, then kinetic performance increases, but electrolyte composition becomes more complex
Solution Approach 1:
The patent optimizes the mass percentage parameter of compound A in the electrolyte to fall within 20-82%, with preferred ranges of 30-75% and further preferred 35-65%. This parameter optimization ensures sufficient lithium ion transport speed enhancement while avoiding excessive complexity in electrolyte formulation and manufacturing processes.
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 effectively reduces lithium precipitation during low-temperature charging, enhancing the battery's kinetic performance and energy density while extending the service life of the battery and associated electronic devices.
Implementation Method 1
adding the compound A into the electrolyte and adjusting the mass percentage a of the compound A to be within the above ranges can effectively dilute a base electrolyte and increase a transport speed of lithium ions in the electrolyte
Implementation Method 2
the separator includes a base film and a porous coating provided on at least one surface of the base film, and a contact angle between the electrolyte and the surface of the porous coating of the separator is 0° to 36°
Data Source
AI summary
A secondary battery includes a positive electrode, a negative electrode, a separator, and an electrolyte. The electrolyte includes a compound A represented by formula:R1 to R6 are each independently selected from a fluorine atom, a cyano group, a sulfo group, an aldehyde group, a substituted or unsubstituted C1-C6 alkoxy group, a substituted or unsubstituted C1-C6 alkyl group, a substituted or unsubstituted C2-C6 alkenyl group, a substituted or unsubstituted C2-C6 alkynyl group, a substituted or unsubstituted C6-C12 aryl group, and a substituted or unsubstituted C6-C12 aryloxy group. During substitution, substituents of the groups are each independently selected from a fluorine atom, a C1-C3 alkyl group, or a C2-C4 alkenyl group. The separator includes a base film and a porous coating, and a contact angle between the electrolyte and the surface of the porous coating of the separator is 0° to 36°.