Comparison of power lithium-ion batteries at home and abroad -Lithium - Ion Battery Equipment
Analyze the comparative test of power lithium-ion battery at home and abroad
According to the GB/T31484GB/T31485GB/T31486 test standard, the battery samples of different materials and different packaging forms (soft package, square hard shell and cylindrical winding) at home and abroad were selected for benchmarking analysis, including 4 domestic lithium iron phosphate batteries, 3 ternary materials batteries, 1 lithium manganate battery, and 2 Japanese and Korean ternary materials batteries. The test objects are all battery modules as shown in the following table.(Lithium - Ion Battery Equipment)
Energy density comparison
The energy density comparison of the battery sample is shown in the following table. The energy density of the single lithium iron phosphate battery tested by the standard is between 109 and 143 (Wh)/kg, the energy density of the ternary and lithium manganate battery is between 130 and 195 (Wh)/kg, the energy density of the F-type 36Ah flexible packaging ternary battery is up to 194.93 (Wh)/kg, and the energy density of the J-type 35Ah lithium manganate battery is close to 130 (Wh)/kg. In general, The energy density of ternary battery is higher than that of lithium iron phosphate battery, and the best lithium iron phosphate battery in China can reach 143 (Wh)/kg.
After the module is formed, the energy density decreases due to the connectors and fixed supports, and the specific energy loss rate is shown in the table above. The loss of energy density of F-type 36Ah flexible packaging three-element battery module is the largest. The important reason is that it contains heat dissipation device and shell, and the metal shell designed for the safety of the module is thick; The A42Ah square hard shell lithium iron phosphate battery and the E-type 33Ah square hard shell ternary battery have the smallest energy density loss after they form a module. The important thing is that they do not include the module shell, have no fixed device, and only add the weight of the connector. The power lithium battery module and system energy density are the key to whether electric vehicles can compete with traditional fuel vehicles in the future market. The lightweight design of the power lithium battery module and battery system in the future is the key, It is the key technology to improve the range of electric vehicles.
Low temperature performance comparison
The low temperature performance of power lithium battery for automobile is the bottleneck that restricts the use efficiency of electric vehicles in winter. The low temperature performance of power lithium battery is mainly affected by factors such as the positive and negative electrode materials of the electrolyte. Under low temperature environment, part of the solvent of the electrolyte solidifies, resulting in difficulty in electron migration and low conductivity; The ion is greatly blocked in the electrolyte and the ion migration is slow, which leads to the reduction of the charge and discharge efficiency of the power lithium battery. The comparison of the low temperature discharge performance of the battery sample at - 20 ℃ is shown in the figure below. It can be seen that the difference of the discharge curve of the lithium iron phosphate battery at - 20 ℃ is large, which can be characterized as the difference of the internal resistance of the lithium iron phosphate battery at low temperature. The D type 270Ah square hard shell lithium iron phosphate battery has the smallest initial discharge voltage drop, The low temperature discharge curve of the ternary battery with the best low temperature performance has the same trend, and the low temperature discharge performance is generally better than that of the lithium iron phosphate battery. Due to the different low temperature discharge depths, the discharge curve of the H-type 28Ah flexible packaging ternary battery is slightly shorter. Among the ternary battery, the I-type 6.3Ah cylindrical winding ternary battery has the largest internal resistance at low temperature, the lowest voltage platform, and the worst low temperature performance.
High temperature performance comparison
Under high temperature, the internal ion movement speed of the battery increases, the concentration polarization and electrochemical polarization are reduced, the internal resistance of polarization is reduced, and the internal chemical reaction heat of the battery is increased. Excessive high temperature will cause the diaphragm to shrink, and the electrolyte will have side reactions, resulting in the reduction of battery life stability GB/T31486 requires the battery to be fully charged at room temperature, Evaluate the discharge capacity of power lithium battery after storage at 55 ℃ for 5 hours. Compare the high temperature discharge performance of battery samples.
According to the GB/T31484GB/T31485GB/T31486 test standard, the battery samples of different materials and different packaging forms (soft package, square hard shell and cylindrical winding) at home and abroad were selected for benchmarking analysis, including 4 domestic lithium iron phosphate batteries, 3 ternary materials batteries, 1 lithium manganate battery, and 2 Japanese and Korean ternary materials batteries. The test objects are all battery modules as shown in the following table.(Lithium - Ion Battery Equipment)
Energy density comparison
The energy density comparison of the battery sample is shown in the following table. The energy density of the single lithium iron phosphate battery tested by the standard is between 109 and 143 (Wh)/kg, the energy density of the ternary and lithium manganate battery is between 130 and 195 (Wh)/kg, the energy density of the F-type 36Ah flexible packaging ternary battery is up to 194.93 (Wh)/kg, and the energy density of the J-type 35Ah lithium manganate battery is close to 130 (Wh)/kg. In general, The energy density of ternary battery is higher than that of lithium iron phosphate battery, and the best lithium iron phosphate battery in China can reach 143 (Wh)/kg.
After the module is formed, the energy density decreases due to the connectors and fixed supports, and the specific energy loss rate is shown in the table above. The loss of energy density of F-type 36Ah flexible packaging three-element battery module is the largest. The important reason is that it contains heat dissipation device and shell, and the metal shell designed for the safety of the module is thick; The A42Ah square hard shell lithium iron phosphate battery and the E-type 33Ah square hard shell ternary battery have the smallest energy density loss after they form a module. The important thing is that they do not include the module shell, have no fixed device, and only add the weight of the connector. The power lithium battery module and system energy density are the key to whether electric vehicles can compete with traditional fuel vehicles in the future market. The lightweight design of the power lithium battery module and battery system in the future is the key, It is the key technology to improve the range of electric vehicles.
Low temperature performance comparison
The low temperature performance of power lithium battery for automobile is the bottleneck that restricts the use efficiency of electric vehicles in winter. The low temperature performance of power lithium battery is mainly affected by factors such as the positive and negative electrode materials of the electrolyte. Under low temperature environment, part of the solvent of the electrolyte solidifies, resulting in difficulty in electron migration and low conductivity; The ion is greatly blocked in the electrolyte and the ion migration is slow, which leads to the reduction of the charge and discharge efficiency of the power lithium battery. The comparison of the low temperature discharge performance of the battery sample at - 20 ℃ is shown in the figure below. It can be seen that the difference of the discharge curve of the lithium iron phosphate battery at - 20 ℃ is large, which can be characterized as the difference of the internal resistance of the lithium iron phosphate battery at low temperature. The D type 270Ah square hard shell lithium iron phosphate battery has the smallest initial discharge voltage drop, The low temperature discharge curve of the ternary battery with the best low temperature performance has the same trend, and the low temperature discharge performance is generally better than that of the lithium iron phosphate battery. Due to the different low temperature discharge depths, the discharge curve of the H-type 28Ah flexible packaging ternary battery is slightly shorter. Among the ternary battery, the I-type 6.3Ah cylindrical winding ternary battery has the largest internal resistance at low temperature, the lowest voltage platform, and the worst low temperature performance.
High temperature performance comparison
Under high temperature, the internal ion movement speed of the battery increases, the concentration polarization and electrochemical polarization are reduced, the internal resistance of polarization is reduced, and the internal chemical reaction heat of the battery is increased. Excessive high temperature will cause the diaphragm to shrink, and the electrolyte will have side reactions, resulting in the reduction of battery life stability GB/T31486 requires the battery to be fully charged at room temperature, Evaluate the discharge capacity of power lithium battery after storage at 55 ℃ for 5 hours. Compare the high temperature discharge performance of battery samples.
