Lithium Battery Electrolyte Additives to Prevent Plating and Overcharge Heat
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Solution Overview
Problem
Rechargeable lithium batteries face safety concerns during overcharging and rapid charging, including heat generation and potential cell explosion, as well as reduced cycle-life characteristics.
Innovation Solution
An electrolyte solution for rechargeable lithium batteries is developed, comprising a non-aqueous organic solvent, a lithium salt, and an additive that includes a sulfoxide-based compound and a lithium salt with an oxalate group, which enhances safety and cycle-life performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If conventional electrolyte solutions are used to enable high capacity and high energy density, then battery performance is improved, but safety deteriorates under overcharging and rapid charging conditions due to heat generation and potential cell explosion
Solution Approach 1:
The patent modifies the chemical composition parameters of the electrolyte by introducing a specific additive package containing a cyclic carboxylate compound (0.01-5 wt%) and a phosphorus-containing compound (0.01-5 wt%). This parameter change in the electrolyte formulation enables the system to maintain high energy density while improving safety under overcharging and rapid charging conditions through suppressed heat generation and prevented cell explosion.
Solution Approach 2:
The patent creates a composite electrolyte system by combining conventional electrolyte components with specific additive compounds (cyclic carboxylate and phosphorus-containing compound). This composite approach allows the electrolyte to simultaneously provide high ionic conductivity for energy density while the additive components work synergistically to enhance safety by suppressing exothermic reactions and preventing thermal runaway.
2Productivity
If rapid charging is implemented to improve charging speed, then productivity is improved, but lithium electrodeposition occurs on the negative electrode causing increased internal resistance
Solution Approach 1:
The patent applies preliminary action by having the cyclic carboxylate and phosphorus-containing compounds in the electrolyte proactively form protective interfaces on the negative electrode surface before rapid charging begins. This pre-formed protective layer prevents lithium electrodeposition during subsequent rapid charging operations, allowing high charging speeds to be maintained without the harmful accumulation of internal resistance that would otherwise occur.
3Use of energy by moving object
If overcharging is permitted to maximize energy utilization, then energy capacity is improved, but temperature increases rapidly leading to safety hazards
Solution Approach 1:
The patent converts the potentially harmful overcharging condition into a beneficial outcome by using the cyclic carboxylate and phosphorus-containing compounds to transform the harmful thermal runaway process. These additives modify the electrochemical reactions during overcharging to suppress exothermic reactions, thereby converting what would be a dangerous temperature increase into a controlled process that maintains safety while allowing full energy capacity utilization.
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 electrolyte solution effectively suppresses temperature increases during overcharging, prevents lithium electrodeposition, and maintains excellent room-temperature cycle-life characteristics, thereby enhancing the safety and performance of rechargeable lithium batteries.
Implementation Method 1
the electrolyte plays a role (e.g., an important role) in transferring lithium ions, and can exhibit significantly higher ionic (e.g., ion) conductivity by including organic solvents and lithium salts
Implementation Method 2
the electrolyte solution effectively suppresses temperature increases during overcharging
Implementation Method 3
When a rechargeable lithium battery is in an overcharged state, the battery generates heat rapidly
Implementation Method 4
if (e.g., when) a rechargeable lithium battery is subject to rapid charging, there is a problem where lithium is electrodeposited on the negative electrode
Data Source
AI summary
An electrolyte solution for a rechargeable lithium battery according to some embodiments includes a non-aqueous organic solvent; a lithium salt; and an additive, wherein the additive includes a first compound represented by Chemical Formula 1, and a second compound represented by Chemical Formula 2.The definitions of Chemical Formulas 1 and 2 are as described in the specification.