Battery low dc resistance test and analysis

Source: 2020 - 04 - 04 then hits: time low dc resistance test and analysis of the battery pack battery dc resistance test method, battery discharge current switch quickly, in a short time ( Millisecond) Within the change of discharge current, the test device according to the transient voltage and current values, approximate calculation dc resistance. Three yuan respectively under different temperature test the dc resistance of the battery. Test results as shown in table 3 and figure 3: dc resistance by ohmic resistance, concentration polarization resistance and activation polarization resistance of three parts. Ohm resistor is determined by the battery itself material, so once the ohmic resistance determined, its value is a constant. Activation of the polarization resistance is determined by the nature of the electrochemical reaction system. After determined the battery system and structure, also determine the induced polarization resistance. Concentration polarization resistance is caused by involved in the electrode reaction ion concentration change. Therefore, low environmental temperature will reduce the rate of cell activity and the ions move, participate in the electrochemical reaction of ion concentration will also reduce, battery internal resistance will also increase. So when the temperature falls, the dc resistance increased. 3. 4 battery power in low temperature performance comparison of three yuan respectively battery and lithium iron phosphate battery power of low temperature test. Specific results are shown in figure 4, See page 4) 。 Can see from figure 4, and the loss of environmental temperature, two battery value is lower, this is because the temperature is reduced, the battery internal electrochemical activity, therefore the discharge of the battery capacity is abate, and SOC loss at the same time, discharge power has also been gradually reduce, this is due to the loss of capacity, discharge capacity, reducing the value of power. Can be found by comparison and low temperature power ternary group was obviously higher than that of lithium iron phosphate batteries, it shows that the ternary group in low power features is superior to the lithium iron phosphate batteries. 4 conclusion through the above performance test and data analysis, it is concluded that the ternary battery low temperature performance is better than that of the conclusion of the lithium iron phosphate batteries. Preliminary analysis shows that the lithium iron phosphate is a kind of structure of peridotite, belongs to the orthogonal crystal system. Therefore, lithium ion migration velocity is slow, electron transfer rate is low, which greatly restrict the exertion of the low temperature performance. With three yuan battery instead of lithium iron phosphate batteries as the future of electric vehicles initiative core is feasible and applicable.