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  3 2.What is the IEC standard cycle life test?   IEC stipulates that the standard cycle life test for NiMH batteries is:   After the battery is discharged at 0.2C to 1.0V/piece 01) Charge at 0.1C for 16 hours, then discharge at 0.2C for 2 hours and 30 minutes (one cycle)   02) Charge at 0.25C for 3 hours and 10 minutes, discharge at 0.25C for 2 hours and 20 minutes (2-48 cycles)   03) Charge at 0.25C for 3 hours and 10 minutes, discharge at 0.25C to 1.0V (49th cycle)   04) Charge at 0.1C for 16 hours, leave for 1 hour, and discharge at 0.2C to 1.0V (50th cycle). For NiMH batteries, repeat 1-4 for a total of 400 cycles, and the 0.2C discharge time should be greater than 3 hours; for NiCd batteries, repeat 1-4 for a total of 500 cycles, and the 0.2C discharge time should be greater than 3 hours.

  I. Some important concepts Lithium iron phosphate battery (LFP) and ternary lithium battery (NCM/NCA) are two mainstream lithium-ion battery technologies. The following are their main differences:

Lithium-ion battery overview Lithium-ion battery is a secondary battery. Its working principle is: during the charge and discharge process, lithium ions are in a state of movement from positive electrode → negative electrode → positive electrode. During the charge and discharge process, lithium ions are intercalated and deintercalated back and forth between the two electrodes. That is, during charging, lithium ions are deintercalated from the positive electrode and intercalated into the negative electrode through the electrolyte, and the negative electrode is in a lithium-rich state. The opposite is true during discharge. Lithium-ion batteries are complex systems consisting of positive electrode materials, negative electrode materials, electrolytes , separators, conductive agents, binders and packaging materials. Due to their high operating voltage, high specific energy density, long cycle life and wide operating temperature range, lithium-ion batteries have been widely used in new ene...

1. Electrolyte It is an important component of lithium batteries. It conducts lithium ions inside the battery and has an important impact on the performance and life of the battery. Lithium battery electrolyte is usually composed of organic solvents, electrolytes and additives.   Organic solvent is the main component of electrolyte, which is usually a flammable, explosive and toxic liquid, such as dimethyl carbonate (DMC), ethyl methyl carbonate (EMC), diethyl carbonate (DEC), etc.  These organic solvents can dissolve electrolytes to form ion conductors, and can also provide a certain electrochemical stability.   Electrolyte is an ion conductor in the electrolyte, which is usually a lithium salt,  such as LiPF6, LiBF4, LiClO4, etc. These lithium salts can dissociate into lithium ions and negative ions in the electrolyte, thereby realizing the conduction of lithium ions.   Additives are some chemical substances added to improve the performance of the electrolyt...

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.