What are the effects of connector temperature rise on the performance of lithium batteries?
At present, in the field of energy storage, the use and development of lithium batteries are very rapid. Lithium battery energy storage has the advantages of high energy density, long service life, green environmental protection, etc., but there are also some disadvantages, high production costs, poor safety performance, and explosions. The safety design of the thermal management system is very important for the application of lithium batteries. The connector is an indispensable element in series and parallel between battery packs. Its temperature rise effect has a very great effect on the entire lithium battery energy storage system. Large impact, so low temperature rise design has become an inevitable trend in connector development.
In a lithium battery energy storage system, the sensitivity of a lithium battery to temperature mainly stems from the temperature sensitivity of its material physicochemical properties. Temperature directly affects the activity and conductivity of the electrode material, the insertion and extraction of lithium ions on the electrode, the lithium ion permeability of the separator, etc., which in turn affects the electrochemical reaction inside the battery, which is externally expressed as the temperature of the power battery Sensitivity. Since the power battery has a suitable operating temperature range, within this range, as the temperature increases, the activity of its internal active substance is greater, the battery's charge and discharge voltage and capacity increase accordingly, and the internal resistance of the battery decreases accordingly. The discharge efficiency also increases accordingly. However, when the temperature exceeds a certain range, the temperature is too high will accelerate the progress of the side reactions inside the battery, these side reactions consume lithium ions, solvents, electrolytes, etc., resulting in deterioration of battery performance.
Studies have shown that when the battery continues to work above 45 ℃, its cycle life is significantly reduced, this situation is more obvious at high rate charge and discharge. Therefore, if you work in a high-temperature environment for a long time, the life of the power battery will be significantly shortened, its performance will be greatly reduced, and even a safety accident will be caused. Similarly, if the temperature is too low, the activity of the active material inside the battery will be significantly reduced, its internal group and polarization voltage will increase, the charge and discharge power and capacity will be significantly reduced, and even cause the battery capacity to irreversibly decay, and bury hidden safety risks. Especially during the charging process, under the action of an external electric field in the charging device, lithium ions are extracted from the positive electrode material into the electrolyte and move to the negative electrode, and then into the negative electrode material composed of graphite, and form a LiC compound.
In addition, the uneven distribution of the temperature field inside the battery box for a long time will also cause the imbalance of the performance of each battery module and cell, especially the aging rate of the battery distributed in the high temperature area will be significantly faster than the low temperature portion, and the accumulation over time The difference in physical properties between different batteries will become more and more obvious, so that the consistency between the batteries becomes worse, and even premature failure occurs, shortening the life of the entire power battery system.
The connector is a necessary element for series and parallel connection between the battery packs. When the battery pack is charged and discharged, the passage of large current will cause the connector to have a thermal effect. When the temperature of the connector rises above the temperature of the battery pack, the temperature will be transmitted. To the inside of the battery, which affects the stability of the battery, so that the characteristics of the connector to achieve low temperature rise becomes a necessary condition. The dedicated connector for energy storage adopts the terminal technology of the company's own intellectual property rights, and the inside of the terminal is in contact with the pin The surface is kept in the optimal area, which effectively reduces the contact resistance, reduces the overcurrent density, and reduces the current temperature rise. At the same time, the new appearance design design multiple surfaces into a corrugated fan shape to improve the heat dissipation function.
In addition, the metal material adopts imported high-purity copper, which has high conductivity and stable over-current temperature rise. The plastic material uses a unique alloy material, which combines a variety of plastic characteristics, combines high strength and high toughness, and meets fire protection requirements. It has a high thermal conductivity and speeds up heat dissipation. In the connection technology of internal terminals and wire nose, the patented FIRST technology is adopted to ensure the reliability of the connection between the two, increase the contact area, and effectively reduce the overcurrent temperature rise. At the same time, The stable and firm multi-point crimping process effectively reduces the temperature rise of the connection between the wire nose and the wire, and ensures the consistency of the temperature rise. The company's current temperature rise test results of connectors of different current levels can be controlled below 35 degrees Celsius (ambient temperature 20 degrees Celsius).
If you want to know more, our website has product specifications for connector, you can go to ALLICDATA ELECTRONICS LIMITED to get more information