Currently, the application and development of lithium-ion batteries in the energy storage field are very rapid. Lithium-ion battery energy storage has advantages such as high energy density, long service life, and green environmental protection, but it also has some drawbacks, such as high production cost, poor safety performance, and the risk of explosion. Therefore, the safety design of the thermal management system is crucial for the application of lithium-ion batteries. As an indispensable component for connecting battery packs in series and parallel, the temperature rise effect of connectors has a great impact on the entire lithium-ion battery energy storage system. Therefore, low temperature rise design has become an inevitable trend in connector development.
In lithium-ion battery energy storage systems, the temperature sensitivity of lithium-ion batteries largely stems from the temperature sensitivity of their material physicochemical properties. Temperature directly affects the activity and conductivity of electrode materials, the insertion and extraction of lithium ions on the electrodes, and the lithium-ion permeability of the separator, thus influencing the internal electrochemical reactions of the battery, which manifests externally as the temperature sensitivity of power lithium batteries. Because power lithium batteries have a suitable operating temperature range, within this range, as the temperature increases, the activity of the internal active materials increases, leading to increased charge/discharge voltage and capacity, a corresponding decrease in internal resistance, and an increase in charge/discharge efficiency. However, when the temperature exceeds a certain range, excessively high temperatures accelerate internal side reactions, which consume lithium ions, solvents, and electrolytes, resulting in battery performance degradation. Studies have shown that when batteries operate continuously above 45°C, their cycle life significantly decreases, a situation even more pronounced during high-rate charge/discharge cycles.
Therefore, if a power lithium battery operates in a high-temperature environment for an extended period, its lifespan will be significantly shortened, its performance will be greatly reduced, and it may even lead to safety accidents. Similarly, excessively low temperatures will significantly reduce the activity of the active materials inside the battery, increase its internal polarization voltage, and significantly reduce its charging and discharging power and capacity, even causing irreversible capacity decay and creating safety hazards. Especially during charging, under the application of an external electric field in the charging equipment, lithium ions are extracted from the positive electrode material, enter the electrolyte, and move towards the negative electrode, successively entering the graphite-based negative electrode material and forming LiC compounds. If the temperature drops and the charging speed is too fast, lithium ions may not have enough time to enter the negative electrode to form LiC compounds. In this case, lithium ions near the negative electrode will capture electrons and become metallic lithium, aggregating to form lithium dendrites. The growth of these lithium dendrites may puncture the separator, causing a short circuit.
In addition, the uneven distribution of temperature field inside the battery box over a long period of time will also cause the performance of each battery module and cell to be unbalanced. In particular, the aging rate of batteries distributed in the high temperature area will be significantly faster than that in the low temperature area. As time accumulates, the differences in physical properties between different batteries will become more and more obvious, which will lead to poor consistency between batteries and even premature failure, thus shortening the life of the entire power lithium battery system.
As an essential component for connecting battery packs in series and parallel, connectors experience thermal effects during charging and discharging due to the large current flowing through them. When the connector temperature rises above the battery pack temperature, heat is transferred to the battery interior, affecting its stability. Therefore, achieving low temperature rise in connectors is crucial. LianDong's energy storage connectors utilize proprietary terminal technology, maintaining optimal contact area between the terminal interior and pins to effectively reduce contact resistance, current density, and temperature rise. Simultaneously, the novel design incorporates corrugated surfaces on multiple surfaces. The fan-shaped design enhances heat dissipation. Furthermore, the metal material utilizes imported high-purity copper, boasting high conductivity and stable overcurrent temperature rise. The plastic material employs a unique alloy, combining the properties of various plastics, exhibiting both high strength and high toughness, meeting fire resistance requirements while possessing a high thermal conductivity for accelerated heat dissipation. Regarding the internal terminal and lug connection technology, FIRST's patented technology ensures reliable connection, increases the contact area, and effectively reduces overcurrent temperature rise. Simultaneously, the stable and robust multi-point crimping process effectively reduces the connection temperature rise between the lug and the conductor, ensuring temperature consistency. Currently, the company's temperature rise test results for connectors of different current ratings are all controlled below 35 degrees Celsius (ambient temperature 20 degrees Celsius).
Lithium-ion battery energy storage is an inevitable trend in the development of the times. Ensuring the safe and reliable operation of lithium-ion batteries is the primary condition for the operation of energy storage systems. High-current connectors are an indispensable part of lithium-ion battery energy storage. Jiangsu Liandong Power Co., Ltd. has always adhered to the product design philosophy of safety, reliability, and environmental protection, supplying dedicated electrical connectors for energy storage lithium-ion batteries.
