Terms related to battery

1. The core part of the electrode (electrode) battery, it is composed of active material and conductive skeleton. Active material refers to the material that participates in the flow reaction in the positive and negative electrodes. It is the source of electrical energy in the chemical power source and an important part that determines the basic characteristics of the chemical power source. 2. Energy and specific energy The energy of a battery refers to the electrical energy that the battery can output for external work under certain discharge conditions. It is usually expressed in watt-hours (Wh). Specific energy refers to the energy given by the battery per unit weight or unit volume, also known as weight specific energy or volume specific energy, also known as energy density, usually expressed in Wh/kg or Wh/L. 3. Power and specific power The power of a battery refers to the energy output by the battery per unit time under certain discharge conditions, in watts (W) or kilowatts (KW). The battery output power per unit weight or unit volume is called the specific power, and its size represents the size of the working current that the battery can withstand. 4. Capacity (capacity) The parameter of the battery's ability to store energy. For example: 160mAh means that the battery is discharged at a constant current of 160mAh under load, and it can be left for about 1 hour. With the same load, discharge with 80mA constant current, about 2 hours. 5. The energy that C-Rate can release under different currents. Generally speaking, the battery cell needs to detect the discharge performance under different constant current conditions. Generally divided into the following four types: 0.2C, 0.5C, 1C, 2C. Take a 1600mAh battery as an example: 6. Cycle Life (CycleLife) battery life parameter. This cycle life detection is carried out on an Arbin machine. Basically, the cell is charged and discharged multiple times and the cell capacity is reduced to 80% as the detection point. The battery cell will have energy loss (impedance, thermal energy) after each charge and discharge, so it will cause a loss of capacity, and the standard of CycleLife is to charge and discharge with 1C constant current. When the capacity of the battery cell drops to 80% of its original capacity after many times of charging and discharging, we use this point as a checkpoint to check the number of cycles of the battery cell in this state. A good battery cell can generally be charged and discharged at a constant current of 1C for many times, and it has a capacity of about 80% when it reaches 300 cycles. 7. Internal resistance (Impedance) The internal resistance of a battery refers to the resistance experienced by the current passing through the battery, including the ohmic resistance and the polarization resistance of the electrode during the electrochemical reaction. The ohmic resistance is mainly composed of the electrode material, electrolyte, the resistance of the isolation membrane, and the contact resistance of each part. In addition, it is also related to the size, structure, and assembly of the battery. Polarized internal resistance refers to the internal resistance caused by the polarization of the positive electrode and negative electrode of the battery during the chemical reaction. It is related to the nature of the active material, the structure of the electrode, and the manufacturing process of the battery, especially the working conditions of the battery. In short, internal resistance is an important indicator that determines battery performance. It directly affects the battery's working voltage, working current, output energy and power. For a practical battery, the smaller the internal resistance, the better. 8. Open circuit voltage (OCV--OpenCircuitVoltage) u0026 working voltage (WorkVoltage) Open circuit voltage refers to the potential difference between the two poles of the battery when there is no current through the external circuit. Working voltage, also known as discharge voltage or terminal voltage, refers to the potential difference between the two poles of the battery when current flows through the external circuit. The operating voltage is always lower than the open circuit voltage. 9. Formation is the initial use of the battery, because when Li+ is charged for the first time, Li+ is inserted into the graphite for the first time, and an electrochemical reaction occurs in the battery. That is, when charging for the first time, a SEI (Solid Electrolyte Interface) layer is formed. The SEI layer is wrapped around the graphite layer, allowing Li+ to be inserted into the graphite smoothly, but not allowing electrons to pass through. The SEILayer is formed as EC+Li+ eàLiR+CO2 (gas is present, so airbags are required during formation), and electrons must participate in its formation, so when the SEILayer is thick enough, the reaction stops, and SEILayer has a major impact on the battery's electrical properties. So the process of battery formation is very important. Disclaimer: Some pictures and content of articles published on this site are from the Internet. If there is any infringement, please contact to delete. Previous article: What codes are on the lithium battery cell?