How do you calculate the specific energy density of a power battery?

Battery energy: refers to the electrical energy output by external work under certain discharge conditions;

Specific energy: the energy given by a unit weight or a unit of volume, called weight ratio energy or volume ratio energy.

The weight ratio energy and volume ratio energy of lithium iron phosphate are:

Pure electric vehicle battery: about 110Wh/kg; 210Wh/L

Hybrid electric vehicle battery: about 65Wh/kg; 120Wh/L

The battery pack generally refers to the battery core plus the protective board portion, and the battery pack generally refers to the battery pack plus the outer casing portion.

The specific energy of the battery pack: similar to the specific energy of the battery core

Specific energy of the battery pack: related to the weight and volume of the outer casing and other accessories.

The specific energy refers to the energy per unit weight or unit volume, and the specific energy of the battery is the amount of electric energy released by the electrode material of the unit mass participating in the electrode reaction.

Battery power than what is _ battery energy than the energy density calculated how

The specific energy of the battery refers to the energy that can be output per unit mass or unit volume of the battery, and the unit is W·h/kg or W·h/L, respectively.

Specific energy has a theoretical ratio of energy to actual energy. The theoretical specific energy refers to the energy that can theoretically be output when 1 kg of the battery reaction material is completely discharged. The actual specific energy is the actual energy that can be output from 1 kg of battery reactive material.

It is commonly used energy to compare different battery series.

Due to various factors, the actual specific energy of the battery is much smaller than the theoretical specific energy. The relationship between actual specific energy and theoretical specific energy is as follows:

W real = W KvKRKm

Kv-voltage efficiency (the ratio of the operating voltage of the battery to the electromotive force);

KR-reaction efficiency (indicating the utilization of active substances);

Some of the Km-mass efficiency batteries do not participate in the flow response but are necessary.

Substance, the proportion of these substances should be reduced to increase the proportion of active substances

example. The ratio between the two is quality efficiency.

The specific energy of the battery is a comprehensive indicator, which reflects the quality level of the battery and also indicates the technical and management level of the manufacturer. Usually, the manufacturer does not independently evaluate this indicator, but it is often used as a measure when assessing the level of battery produced.

How to calculate the specific energy density of power battery

The battery is considered to calculate the battery energy density, first of all to understand the common types of common lithium batteries, lithium batteries are mainly divided into two.

The first lithium battery: represented by domestic new energy (ATL battery), Bangkai battery, Meibai, BAK, Sanhe and Chaoyang.

The material used in this kind of lithium battery is generally ternary, also known as lithium cobaltate. It has the advantages of large capacity and high energy density in various cell factories. Now the energy density of ternary batteries is around 580Wh/liter, cobalt. The working voltage of lithium acid is generally 2.75V~4.2V. Like the domestic new energy enterprise ATL is now doing the 4.35V voltage system battery, the energy density can also be as high as 650Wh/liter.

These batteries are commonly used on smartphones, tablets, laptops, and Bluetooth headsets.

The material used in this kind of lithium battery is generally ternary, also known as lithium cobaltate. It has the advantages of large capacity and high energy density in various cell factories. Now the energy density of ternary batteries is around 580Wh/liter, cobalt. The working voltage of lithium acid is generally 2.75V~4.2V. Like the domestic new energy enterprise ATL is now doing the 4.35V voltage system battery, the energy density can also be as high as 650Wh/liter.

These batteries are commonly used on smartphones, tablets, laptops, and Bluetooth headsets.

There is a tragic point that many domestic manufacturers use ternary materials to discharge batteries more than 5C. For example, battery companies such as Chaowei, Tianneng, Foster, and Electric Power can be used in unicycles. On the thinking car and electric motorcycle, the performance can meet the customer's product requirements and be recognized by the majority of users.

The second lithium iron phosphate battery: a power battery company represented by domestic battery manufacturers such as BYD, Waterma, and AVIC Lithium.

The material used in this battery is lithium iron phosphate, referred to as iron battery, which is mainly known for its long safety and cycle life. The working voltage of iron battery is generally between 2.3v and 3.65V, and the cycle life is up to 2000 times. Power battery companies can expand the battery operating voltage to between 2.0V and 3.65V.

Such power batteries are often used in electric buses, electric vehicles, electric forklifts, and mobile stations.

The calculation method of the cell core energy density is as follows:

Energy density (Wh / liter) = capacity & TImes; platform voltage ÷ volume ÷ 1000 (converted units)

The platform voltage of the iron battery is 3.2V; the platform voltage of the ternary lithium battery is generally 3.7V.

Cylindrical volume = πr2 & TImes; h;

Rectangular volume = long & TImes; width & TImes; high;

Power battery material

For the battery, it must meet the requirements of high power, high energy, and energy. The core raw materials that are most concerned with the battery are the positive electrode, the negative electrode, the diaphragm, the electrolyte, etc., plus the content of the cascade utilization and resource recovery after the battery is terminated.

Cathode material: The inside is mainly made of ternary materials, especially the high-nickel ternary materials.

Anode material: There are still many graphite materials, such as artificial graphite, natural graphite and so on.

Diaphragm: From the current and future period of time, it is still based on polyolefin materials. Whether it is polypropylene or polyethylene, it will be used in power batteries. It may be such a development trend. For such a development trend and requirement of high energy density, polyolefin separator is a hot spot of research and development and a hot spot of industrialization.

Electrolyte: At present, lithium hexafluorophosphate is still the main one. Now some new electrolytes, such as lithium FSI and lithium TFSI, are still used in the form of additives.