Secondary Battery Anode Capacitance and Silicon Additives for Fast Charging
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Solution Overview
Problem
Secondary batteries, particularly lithium-ion batteries, face challenges in balancing fast charging and high capacity, leading to issues like lithium precipitation, dendrite formation, and reduced cycle life, which can result in safety concerns and decreased performance.
Innovation Solution
A secondary battery design that includes a negative electrode plate with controlled non-faradaic capacitance, compaction density, and OI value, combined with an electrolyte solution containing a silicon-containing compound, such as tris(trimethylsilane) phosphate, to enhance reaction activity, reduce impedance, and suppress side reactions, thereby enabling fast charging and improved power performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the non-faradaic capacitance of the negative electrode plate is increased to accelerate the non-faradaic process and improve reaction activity, then the kinetic performance is improved, but the impedance between the electrolyte solution and the electrode interface increases
Solution Approach 1:
The patent optimizes the non-faradaic capacitance parameter of the negative electrode plate within a specific range (1-5 nF) to balance reaction activity and impedance. By controlling this parameter, the patent achieves improved kinetic performance while maintaining acceptable impedance levels, directly resolving the technical contradiction between speed and harmful factors.
Solution Approach 2:
The patent introduces a silicon-containing compound as an intermediary substance in the electrolyte solution. This compound forms a stable passivation film at the electrode interface, which acts as a mediator to reduce impedance while allowing the non-faradaic process to proceed efficiently, thus resolving the contradiction between improved reaction activity and reduced impedance.
2Productivity
If fast charging capability is enhanced by improving kinetic performance, then charging time is reduced, but side reactions between the negative electrode plate and electrolyte solution increase
Solution Approach 1:
The patent converts the potentially harmful side reactions into a beneficial outcome by using the silicon-containing compound to form a stable passivation film. This film prevents further harmful side reactions while allowing the desired fast charging process to occur, effectively converting the harmful effect into a protective mechanism that enables high productivity.
Solution Approach 2:
The patent controls the concentration of the silicon-containing compound in the electrolyte solution within a specific range to optimize the formation of the passivation film. By adjusting this parameter, the patent achieves the right balance between enabling fast charging and suppressing side reactions, resolving the contradiction between productivity and harmful factors.
3Power
If the reaction between reactive sites of the negative electrode plate and electrolyte solution is increased to improve charging performance, then fast charging capability is enhanced, but cycle stability and safety deteriorate
Solution Approach 1:
The silicon-containing compound acts as an intermediary that forms a protective passivation film at the electrode interface. This film mediates the interaction between the negative electrode plate and electrolyte solution, allowing beneficial charging reactions to proceed while blocking harmful reactions that would compromise cycle stability and safety, thus resolving the contradiction between power and reliability.
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 accelerates the non-faradaic process, improves kinetic performance, and enhances cycle stability and safety by forming a stable passivation film, allowing for rapid charging and high-rate discharge capabilities while maintaining battery durability.
Implementation Method 1
by adding a silicon-containing compound additive to the electrolyte solution, it is possible to form a stable passivation film at the positive and negative electrode interface
Implementation Method 2
by adjusting the value of the non-faradaic capacitance Cdl of the negative electrode plate, the non-faradaic process of the negative electrode plate is accelerated, the reaction activity is improved
Data Source
AI summary
A secondary battery and a power consumption device are provided in the present application. The secondary battery includes a positive electrode plate, a negative electrode plate, a separator, and an electrolyte solution. The negative electrode plate has a non-faradaic capacitance Cdl nF satisfying 1≤Cdl≤5. The electrolyte solution includes an additive, and the additive includes a silicon-containing compound. In the present application, by reasonably adjusting the relationship between the non-faradaic capacitance of the negative electrode plate and content of the additive in the electrolyte solution, the secondary battery has characteristics of high capacity and rapid charging.