According to the different electrolyte materials used in lithium ion batteries, lithium ion batteries can be divided into two categories: liquid lithium ion batteries (LIB) and polymer lithium ion batteries (LIP). The polymer electrolytes used in polymer lithium ion batteries can be “dry” or “colloid”, and most of them currently use colloid electrolytes.
The biggest feature of polymer lithium-ion batteries is that they have high energy density, high safety, long cycle life and low cost, and can be miniaturized, thin, and lightweight. The polymer lithium-ion battery developed and produced by Weihai Dongsheng Energy Technology Co., Ltd. applies advanced technologies such as mesh current collectors, porous electrodes and porous separators, which effectively reduce the physical and chemical heat generated during the charging and discharging process of the battery, and improve the performance of the battery. Safety and high-rate charge-discharge performance; solve the problem of wide operating temperature range (mainly low-temperature performance) by modifying the electrolyte, positive and negative materials. If you are interested in buying some lithium-ion batteries, you can enter Tycorun Lithium Battery for consultation and purchase.
1) The safety of the battery
Battery heat generation and thermal runaway are the main causes of battery safety hazards. From the theory of heat generation, it can be divided into physical heat generation and chemical heat generation. Physical heat generation is basically the heat generated by the resistance of the material when current passes through, and chemical heat generation is basically friction heat generation during ion exchange and later concentration polarization performance The resistance value is too large to generate heat. To solve the problem of physical heat generation, adjust the material, process and structure. First, increase the interface bonding force between the active material and the current collector, solve the uniformity of the current flowing through the current collector, and use a mesh current collector (below) to increase the specific surface area. Improve the current carrying capacity and the uniformity of current dispersion, and effectively alleviate the problem of polarization resistance. In addition, to solve the problem of the interface resistance between the current collector and the active material surface, it is necessary to ensure sufficient electrical conductivity and a certain binding force.
The solution to chemical heat generation is considered from two aspects: firstly, improving the conductivity of Lit, solving the exchange quantity and speed of Li+, and dredging the exchange channels. The technical route is: use organic and inorganic material composite membrane technology combined with phase separation post-processing pore-making technology to form porous electrodes and porous isolation membranes, so that the electrolyte is released from the free state and adsorbed in the material diaphragm and electrode, and its porosity is the same as that of traditional diaphragms. 8-10 times, increase the specific surface area, increase the liquid absorption rate, and combine the material characteristics to prepare high-curvature three-dimensional transparent structure pores, improve the liquid retention rate, greatly improve the exchange rate and exchange rate, and improve the Lit exchange rate and exchange rate. The amount of heat generated by high current work is reduced, and the chemical heat generation is reduced. The AC impedance of the well-designed porous system is about 50% lower than that of other types of batteries.
In the porous polymer lithium-ion battery, since there is no free electrolyte, the polymer skeleton material with low thermal conductivity and high ionic conductivity is used as the support. In the event of accidents and physical damage (gunshots, punctures, shears, bumps, crushes, drops, etc.), the batteries remain highly safe, do not catch fire, do not explode and keep working. The safety of the battery is also very important in the preparation process. For example, the control and treatment of burrs and the hidden dangers of potential defects in the separator can lead to short-circuits during the charging and discharging of the battery and cause thermal runaway. To ensure safety, Weihai Dongsheng Company adopts DC 600 The ~800V high-voltage pulse scanning method eliminates burrs and hidden dangers of diaphragm, so that 100% of the battery for electric vehicles can withstand high-voltage (DC 600V) shocks, thereby ensuring the safety of the battery and the whole vehicle.
(2) Wide operating temperature range
The modified ternary composite material and low-temperature electrolyte combine with porous electrode technology, so that the electrolyte is adsorbed inside the electrode and the diaphragm, and the battery has good low-temperature performance. Reach 56%.-40℃ can also reach 40%
(3) High rate charge and discharge performance
The car needs more current from the power battery when starting, accelerating, and climbing. The starting current of the bus can be as high as several hundred amps. When the vehicle is climbing, if the rate of the battery is poor, the motor will be decelerated and stopped, resulting in a large amount of electricity generated by the battery. Thermal energy not only affects battery life, but also causes safety accidents. In the porous polymer lithium-ion battery, the mesh current collector and foreign warfare technology are used to alleviate the polarization resistance caused by the uneven distribution of large current. Combined with the porous electrode and the porous electrolyte separator composite electrode, the liquid retention rate and liquid absorption of the electrolyte are improved. It increases the exchange channel and exchange amount of Li+, and realizes the rapid exchange of Li+. When the battery is discharged at a high rate, the temperature rise is small and the heat generation is low. It is more suitable for electric vehicles to be used under different working conditions.
(4) Long cycle life and high energy density
The battery is made by the composite grid stack stack process technology. Dongsheng Company adopts the current collector external embedding technology to solve the large current heat dissipation, and combines the conductive glue to pretreat the current collector to solve the interface adhesion between the active material and the current collector. And the problem of excessive interface resistance, solve the problem of interfacial leaching expansion between charge and discharge active materials and current collectors, solve the de-powdering of active materials during high current discharge, improve battery life, select high-voltage platform characteristics of ternary composite materials, for positive, The negative electrode powder material is modified by doping and coating to improve the cycle life. The cycle performance of ordinary L-NCM ternary material is ≥ 1500 times, and the high-end modified ternary material can currently reach 4000 times (25℃, 1C charge). Discharge, DOD=100%, SOC≥80%), the battery energy density can reach 143W·h/kg (bare electricity).
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