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What is electrolyte? The main materials of lithium-ion batteries are: positive electrode, negative electrode, electrolyte, and separator  . As one of the four key materials of lithium-ion batteries, electrolyte is called the "blood" of lithium-ion batteries. From the working principle of lithium ions, lithium-ion batteries are secondary batteries (rechargeable batteries) that mainly rely on the movement of lithium ions between the positive and negative electrodes to work. During the charging and discharging process, Li+ is embedded and de-embedded between the two electrodes: when charging, Li+ is de-embedded from the positive electrode and embedded in the negative electrode through the electrolyte , and the negative electrode is in a lithium-rich state; the opposite is true during discharge.

  1. Composition of electrolyte The basic functions of electrolyte: It transfers lithium ions between the positive and negative electrodes, but insulates electrons to ensure that the battery can be charged and discharged smoothly. Ideal electrolyte requirements: 1) It is an excellent conductor for lithium ions and an insulator for electrons; 2) Except for the migration of lithium ions, no other side reactions occur on the electrode surface; 3) Do not react with other battery components; 4) Good chemical stability; safe and environmentally friendly;

  Lithium-ion battery:   A battery that uses materials that can undergo lithium ion embedding/de-embedding reactions as positive and negative active materials, and uses organic electrolytes or polymer electrolytes containing lithium salts. It is a secondary battery (i.e., a rechargeable battery) that mainly relies on the movement of lithium ions between the positive and negative electrodes to work.

This article introduces the role of lithium battery electrolyte in detail. The electrolyte not only plays a key role in conducting ions to complete the charging and discharging process in the battery, but also has important significance in maintaining the stable performance of the battery, preventing plate corrosion, dissipating heat, controlling temperature, improving energy and power density, providing high voltage and high specific energy, protecting battery safety, and adapting to wide temperature applications. By understanding the role of the electrolyte , it provides a reference for better design and optimization of lithium batteries and improving their performance and safety.

1. Why choose lithium battery? At present, most power batteries are still lithium batteries. Of course, sodium-ion batteries are gradually beginning to be mass-produced, but they are not the main players yet.

1. Classification of battery cells 1.1. Introduction to energy storage Nickel battery: Nickel-metal hydride battery is a good performance battery. The positive active material of nickel-metal hydride battery is Ni(OH)2 (called NiO electrode), the negative active material is metal hydride, also called hydrogen storage alloy (the electrode is called hydrogen storage electrode), and the electrolyte is 6mol/L potassium hydroxide solution. The advantages of nickel battery are: high energy density, fast charge and discharge speed, light weight, long life, no environmental pollution; the disadvantages are slight memory effect, more management problems, and easy formation of monomer battery separator melting.

  1. Production process of battery cells The production process of cylindrical batteries: front process, middle process and back process. Pre-process  : Process the positive and negative electrode materials and current collectors into a certain coating weight and size The positive and negative electrodes Middle process  : Wind the pole piece and diaphragm made in the previous process into a winding core and then put it into the shell. The electrolyte is injected and sealed to form a complete battery structure. Post-process  : An important battery process for the first charging, discharging and activation of cylindrical batteries

  1. Overview of three types of batteries 1. Cylindrical battery cell The cylindrical battery cell was first invented by Sony Corporation of Japan in 1992. It has a long history of development and a high degree of standardization. Common models include 18650, 21700, 46800, etc. It adopts a mature winding process, with a high degree of automation, high production efficiency, good consistency and relatively low cost. For example, the 21700 battery used in Tesla Model 3 and Model Y, and the 46800 battery that is about to be mass-produced, once made the cylindrical battery cell popular in the market. However, there are also some problems with cylindrical batteries. Due to the cylindrical shape, the space utilization rate is low, and in the case of modularization, a large space waste will be caused. At the same time, the radial thermal conductivity is not good, the number of windings of the battery cannot be too many, and the single cell capacity is small. When used in electric vehicle...

A battery cell is the smallest unit of a battery system. Multiple battery cells form a module, and multiple modules form a battery pack. This is the basic structure of a car power battery. A battery is like a container for storing electrical energy. The amount of capacity it can store is determined by the amount of active material covered by the positive and negative electrodes. The design of the positive and negative electrode plates needs to be tailored to different models. The gram capacity of the positive and negative electrode materials , the ratio of active materials, the thickness of the electrode plates, the compaction density, etc. are also crucial to the capacity.

What are battery cells? How many types are there? The cell of a lithium-ion battery is the core unit for storing and providing electrical energy in a lithium battery system. Each cell stores and releases electrical energy through electrochemical reactions. The components of a lithium-ion secondary rechargeable battery include a cell and a protection circuit board. Among them, the cell is the core part of the rechargeable battery responsible for storing electrical energy, while the protection circuit board is responsible for the safety management of the battery. If the protection circuit board is removed, the remaining part is the cell. The quality of the cell directly determines the overall performance and quality of the rechargeable battery.

The coating and drying of lithium battery pole pieces accounts for 8% to 10% of the entire manufacturing cost of lithium batteries, which is mainly due to the low thermal efficiency of the pole piece drying process. In addition, the residual solvent in the pole piece drying process has a great impact on the stability, capacity and cycle life of the subsequent processing of the pole piece. The pole piece drying process not only affects the manufacturing cost of the battery, but also indirectly determines the manufacturing process level and safety.This paper studies the drying characteristics of the coating layer of the positive electrode of LiFePO4 battery under static drying and hot air tunnel drying conditions, and analyzes its drying rules to provide a reference for optimizing the hot air drying process and the development of corresponding drying equipment.

1. What is the coating substrate? In lithium-ion batteries, the positive and negative active materials are coated on the substrate to make the pole pieces, which are then wound or stacked to form the battery cell. The substrates used here are mainly copper foil and aluminum foil. The current lithium battery positive electrode is aluminum foil and the negative electrode is copper foil. This is because copper is easily oxidized at the positive electrode with a higher potential. At the same time, there is a dense oxide layer on the surface of the aluminum foil, which protects the internal aluminum at high potential.

1. Lithium battery pole piece production process The general process of lithium-ion battery pole piece manufacturing is : pulping, coating, drying, rolling, cutting, etc. The specific process flow is shown in the figure below.

1. Basics of Pole Design The lithium battery electrode is a coating composed of particles, which is evenly coated on the metal current collector. The lithium-ion battery electrode coating can be regarded as a composite material, which mainly consists of three parts: