Test Index of Constant Temperature and Humidity Testing Machine The accuracy indexes of parameters of constant temperature and humidity testing machine (such as temperature, humidity, etc.) are the results of detection under no-load state. Some customers might ask: don't the test results under no-load and non-no-load are the same? It must be different. Once the constant temperature and humidity testing machine is placed into the tested product, it will have an impact on the uniformity of environmental parameters in the test chamber. The larger the space occupied by the tested product, the more serious the impact will be. Why? A large number of measured test data show that the temperature difference between the windward side and the leeward side in the flow field can reach 3 ~ 8 ℃, which can be more than 10 ℃ in severe cases. Therefore, several requirements outlined above must be met as far as possible to ensure the uniformity of environmental parameters around the tested product. According to the principle of heat conduction, the temperature of the air flow near the box wall is usually 2 ~ 3 ℃ different from the center temperature of the flow field, and may reach 5 ℃ at the upper and lower limits of high and low temperature. The difference between the temperature of the box wall and the temperature of the flow field near the box wall is 2 ~ 3 ℃ (depending on the structure and material of the box wall). The greater the difference between the test temperature and the external atmospheric environment, the greater the temperature difference. Therefore, the space within the distance from the box wall (100 ~ 150mm) is unusable. Relevant standards stipulate that the wind speed in the warm and wet box shall be less than 1.7m/s during the environmental test. For the test itself, the smaller the wind speed, the better. Excessive wind speed will accelerate the heat exchange between the surface of the test piece and the flowing air flow in the box, which is unfavorable to the authenticity of the test. However, in order to ensure the uniformity in the chamber, it is necessary to have circulating air in the chamber. However, for the rapid temperature change high and low temperature test chamber and the multi factor comprehensive environmental test chamber such as temperature, humidity and vibration, in order to pursue the temperature change rate, it is necessary to speed up the flow rate of circulating air flow in the chamber, and the wind speed is usually 2 ~ 3M / s. Therefore, the wind speed limit is different for different purposes. In order to more accurately simulate the actual environmental conditions suffered by products in nature, it is necessary to ensure that the surroundings of the tested products are under the same temperature environmental conditions in the environmental test. Therefore, the temperature gradient and temperature fluctuation in the test chamber must be limited. In the constant temperature and humidity testing machine, the humidity i...

Comparative Analysis of Cylindrical Lithium Ion Battery and Prismatic Lithium Ion Battery ▶ Battery shape: prismatic lithium-ion batteries can be flexible in any sizes, which the cylindrical battery can’t work the same. ▶ Rate capability: due to the process limitation of cylindrical lithium-ion battery welding multipole tabs, the rate capability is slightly worse than that of prismatic. The same positive electrode material, negative electrode material and electrolyte are used, so the discharge platform is consistent in theory, but the internal resistance of prismatic battery is slightly superior, so the discharge platform is slightly higher. ▶ Product quality: the process of cylindrical lithium-ion battery is very mature, the probability of secondary slitting defects of pole pieces is low, and the winding process is more mature and automatic than the lamination process. At present, the lamination process is still semi manual, so there is an adverse impact on the quality of relevant batteries. ▶ Pole tab welding: the pole tab of cylindrical lithium-ion battery is easier to weld than prismatic battery, and the prismatic battery is prone to false welding, which affects the battery quality. Battery welding machines for them also have different requirements. ▶ Pack composition: cylindrical batteries are relatively easy to use, so the pack method is simple and the heat dissipation effect is good. The heat dissipation of prismatic batteries should be handled well when packing. ▶ Structural features: the chemical activity energy at the corners of the prismatic lithium-ion battery is poor, and the performance of the battery decreases obviously after long-term use. Generally speaking, cylindrical and prismatic batteries have their own advantages and disadvantages. Each battery has its own dominant category. For example, there are more lithium iron phosphate in prismatic batteries. With the introduction of the new subsidy policy for new energy vehicles, the system energy density of batteries has become an important evaluation index. Acey new energy is a professional supplier of prismatic battery machines and cylindrical battery pack machines. Just contact ACEY for more information.   

Working Principle of BMS Lithium Battery Management System What is lithium ion battery BMS system? BMS lithium battery management system can ensure the use safety of power lithium battery pack, which is the primary task of lithium power battery management system. The requirements of battery management system for different cell types are often different. Generally, BMS lithium battery system usually includes detection module and operation control module. 1. The composition of battery management system BMS lithium battery system, commonly known as battery nanny or battery housekeeper, is mainly used to intelligently manage and maintain each battery unit, prevent overcharge and overdischarge of the battery, prolong the service life of the battery and monitor the state of lithium battery. BMS lithium battery management system unit includes BMS battery management system, control module, display module, wireless communication module, electrical equipment, battery pack for supplying power to electrical equipment and collection module for collecting battery information of battery pack. 2. How does the BMS work? The lithium battery BMS determines the state of the whole battery system by detecting the state of each single battery in the power battery pack, and carries out corresponding control adjustment and strategy implementation for the power battery system according to their state, so as to realize the charge and discharge management of the power lithium battery system and each single battery, so as to ensure the safe and stable operation of the power battery system. People will use BMS testing machine in a pack assembly line to do such a job. 3. The role of each BMS module The topology of typical lithium battery management system is mainly divided into two parts: master control module and slave control module. Specifically, it is composed of central processing unit, data acquisition module, data detection module, display unit module, control components, etc. Generally, the data information communication between modules is realized by using internal CAN bussing technology. Based on the functions of each module, BMS can detect the voltage, current, temperature and other parameters of power lithium battery in real time, realize thermal management, balance management, high voltage and insulation detection of power battery, and calculate the remaining capacity, charge and discharge power and SOC & SOH state of power battery. A good BMS lithium battery management system has a temperature sensor, which can monitor the voltage of a single battery pack and detect low-performance batteries before battery pack sealed and finished. This 100% test guarantees higher production, higher battery capacity and reduced warranty commitments. A good battery management system also records the date and information of mechanical impact and deep discharge, so it can avoid false warranty claims. Excellent BMS can also detect the humidity of lithium battery pack to avoid acc...