| As the main power supply device of new energy hybrid electric vehicle,Ni MH power battery pack is one of the key parts of new energy hybrid electric vehicle.In order to extend the service life of battery in vehicle and provide stable and reliable power for vehicle,it is necessary to do in-depth research on the stability and reliability of on-board Ni MH batteryThe Ni MH battery packs on the vehicle are assembled in series,with nominal capacity of 6.0ah-6.5ah and voltage ranging from 120 V to 300 V.In this paper,through the test of the different density of foam nickel on the positive base material of Ni MH battery,the process of slurry density monitoring of 450g/m2,420g/m2 and 380g/m2,the qualification rate of the electrode after forming,and the electric performance test of the battery are comprehensively evaluated.The foam nickel with a surface density of 420g/m2 is selected.The permeability of the slurry is good,and no floating powder is found on the surface of the electrode.When the battery is discharged at 30 times,the platform voltage is above 0.9V,and the electrical performance meets the requirements.The nickel foam can meet the stable operation of the production process and meet the requirements of the electric performance index of the vehicle hybrid power battery,and enhance the reliability of the battery on the vehicle.By adjusting the composition of hydrogen storage alloy powder,the half cell capacity and cycle life of hydrogen storage alloy powder can meet the conventional index.When the PCT platform is adjusted at 0.05 Mpa,the 10 rate discharge capacity of half cell is more than 75%,and the particle size of hydrogen storage alloy powder is controlled at d50 = 40 μ m in the pulverizing process,the screening rate of200 mesh can reach more than 98%,and the screening rate of 400 mesh can reach 40%.Based on the conventional selection of index voltage,capacity and internal resistance range control,one-step selection of voltage drop consistency is added.The battery is adjusted to the premise that the internal state is relatively stable(i.e.charged 50% ～ 60% SOC).The battery is discharged in the way of simulating the limit load current of vehicle,and discharged in a short time of 10 seconds,The batteries with the same voltage drop are selected as one of the combination conditions,and the batteries with the voltage drop of0.02 v are paired in groups to ensure the consistency of individual batteries in each group of battery packs,so as to improve the consistency of vehicle batteries.The choice of nickel foam substrate for Ni MH battery is not the higher the surface density,the better the electrical performance.Under the premise of meeting the charge discharge performance,we should take into account other indicators,such as the size of the internal space of the redox reaction cell,and the bonding state between the active material and the substrate.For the selection of alloy powder materials,the evaluation index of power cell takes the high current discharge capacity into consideration.The influence of hydrogen absorption and hydrogen absorption and desorption platform on the performance of semi battery is analyzed from the pressure,composition and temperature curve,and then feedback the flat table with cut-off voltage when the battery is discharged at high rate.In the process of battery separation,the voltage difference distribution is increased by simulating the vehicle current.After selecting the battery with the same voltage difference and recombining,the consistency of the whole battery in the package is improved obviously.This article have been used in the production practice and received obvious effect. |
