Application of perfluorobutyl iodide in lithium ion battery electrolyte and waste lithium ion battery capacity restoration
By adding perfluorobutyl iodide to the electrolyte of lithium-ion batteries, the problems of poor circulation performance of lithium-ion batteries and the inability to reuse of waste batteries are solved, and the effect of delaying the reduction of discharge capacity and improving circulation performance is achieved, reducing the cost of use And promotes the reuse of resources.
Patent Information
- Application Number
- CN202310963641.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2023-08-02
- Publication Date
- 2025-02-14
AI Technical Summary
The discharge capacity of existing lithium-ion batteries drops rapidly during recycling, resulting in poor circulation performance, high cost of use, and waste batteries cannot be reused.
Add perfluorobutyl iodide to the electrolyte of lithium-ion batteries, and add it to the battery by mixing it with the electrolyte, or directly adding it to the electrolyte, to improve the performance of the electrolyte, delay the decrease in discharge capacity, improve circulation performance, and to repair Discharge capacity of used batteries.
Effectively slow down the rate of discharge capacity of lithium-ion batteries, improve circulation performance, reduce usage costs, and make waste batteries available again, economical and environmentally friendly.
Smart Images
Figure BDA0004372617480000041
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of lithium ion batteries, and in particular to the application of perfluorobutyl iodide in lithium ion battery electrolytes and capacity repair of waste lithium ion batteries. Background Art
[0002] With the increasing attention paid to environmental protection worldwide, the status of lithium-ion batteries as an important clean energy in the power industry and the automotive power industry is also increasing. At present, lithium-ion batteries are widely used in energy storage of power grids and wind and solar power, backup power for household, industrial and commercial use, and power supply for two-wheeled, three-wheeled and automobiles.
[0003] At present, whether in energy storage or in vehicle power, under the condition that the battery energy density is relatively stable, improving the cycle performance of lithium-ion batteries is the fundamental way to reduce the cost of using lithium-ion batteries and improve user satisfaction. Lithium-ion batteries are mainly composed of shells, positive and negative electrodes, diaphragms and electrolytes. Existing literature and patents have disclosed methods for improving the cycle performance of lithium-ion batteries from the perspectives of positive electrode materials, negative electrode materials and electrolytes.
[0004] In terms of electrolyte, by adding additives to the electrolyte, the attenuation rate of the discharge capacity of lithium-ion batteries can be effectively slowed down and the cycle performance of lithium-ion batteries can be improved. However, the current additives have limited improvement on the cycle performance of lithium-ion batteries. After about 70 cycles, the discharge capacity of the battery drops from 100% to about 98.5%; after several thousand cycles, the discharge capacity of the battery will drop significantly and it will be regarded as a waste battery and cannot be used anymore.
[0005] How to effectively slow down the attenuation rate of the discharge capacity of lithium-ion batteries, improve the cycle performance of lithium-ion batteries, and further reduce the cost of using lithium-ion batteries is an urgent problem to be solved. Summary of the invention
[0006] Based on this, there is an urgent need to provide an additive that can improve the performance of lithium-ion battery electrolytes to slow down the discharge attenuation rate of lithium-ion batteries and improve the cycle performance of lithium-ion batteries; there is also an urgent need to provide an electrolyte additive that can restore the discharge capacity of waste batteries so that waste batteries can be reused.
[0007] One of the purposes of the present invention is to provide the use of perfluorobutyl iodide in lithium ion battery electrolyte.
[0008] Furthermore, after the lithium-ion battery is formed, perfluorobutyl iodide is added.
[0009] Furthermore, the perfluorobutyl iodide is first mixed with the electrolyte outside the lithium ion battery, and then added into the electrolyte of the lithium ion battery.
[0010] Furthermore, the perfluorobutyl iodide is directly added into the electrolyte of the lithium ion battery.
[0011] Another object of the present invention is to provide the use of perfluorobutyl iodide in the capacity repair of waste lithium-ion batteries.
[0012] Furthermore, the perfluorobutyl iodide is first mixed with the electrolyte outside the waste lithium ion battery, and then added into the electrolyte of the waste lithium ion battery.
[0013] Furthermore, the perfluorobutyl iodide is directly added into the electrolyte of waste lithium-ion batteries.
[0014] The present invention has the following advantages and effects:
[0015] The present invention can slow down the rate of decrease of the discharge capacity of the lithium ion battery by adding perfluorobutyl iodide into the electrolyte of the lithium ion battery, thereby effectively improving the cycle performance of the battery and reducing the use cost of the lithium ion battery.
[0016] The invention realizes effective recovery of the discharge capacity of the waste lithium ion battery by adding perfluorobutyl iodide into the electrolyte of the waste lithium ion battery (the discharge capacity is less than 80% of the nominal capacity).
[0017] Furthermore, the rate of decrease in discharge capacity of the repaired lithium-ion battery is slower than that before restoration, thereby effectively improving the discharge capacity retention rate of the lithium-ion battery, reducing the use cost of the lithium-ion battery, and allowing waste batteries to be reused, which is economical and environmentally friendly. DETAILED DESCRIPTION
[0018] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.
[0019] The waste lithium-ion battery in the embodiment refers to a lithium-ion battery whose discharge capacity drops below 80% of the rated capacity.
[0020] The following is a detailed description of the application of perfluorobutyl iodide in lithium-ion battery electrolytes through Examples 1-3.
[0021] Example 1
[0022] A commercially available 24Ah (0.5C) square-shell lithium iron phosphate battery from the same manufacturer and the same batch was taken as Sample 1 in Example 1 to test the initial discharge capacity of the battery. An electrolyte containing perfluorobutyl iodide was added to the battery of Sample 1 to test the discharge capacity of the battery after charge and discharge cycles.
[0023] (1) Preparation of electrolyte containing additives: Add a certain amount of perfluorobutyl iodide to the conventional electrolyte according to the proportions in Table 1 and mix well.
[0024] The conventional electrolyte components are: electrolyte lithium hexafluorophosphate, additives VC (vinylene carbonate), PC (propylene carbonate), solvents EC (ethylene carbonate), EMC (ethyl methyl carbonate), DEC (diethyl carbonate).
[0025] (2) Battery initial capacity test: At 25℃±5℃, use a 5V-20A charge and discharge tester to charge at constant current (0.75C) to a voltage of 3.65V, then charge at constant voltage to a cut-off current of 1 / 20C, leave for 30 minutes, and then discharge at constant current to a cut-off voltage of 2.5V. This is one cycle. A total of 4 cycles are performed. The average value of the test discharge battery capacity is taken as the base of the initial discharge capacity, which is calculated as 100%.
[0026] (3) Liquid injection: In a glove box, open the battery liquid injection port and add the electrolyte containing perfluorobutyl iodide in step (1). After the liquid injection is completed, seal the battery, let it stand for 48 hours, and then conduct a charge and discharge test on a machine.
[0027] (4) Charge and discharge test: At 25℃±5℃, use a 5V-20A charge and discharge tester to charge at constant current (0.75C) to a voltage of 3.65V, then charge at constant voltage to a cut-off current of 1 / 20C, leave for 30 minutes, and then discharge at constant current to a cut-off voltage of 2.5V. This is one cycle. The battery's initial cycle discharge capacity retention rate and the 200th cycle discharge capacity retention rate are tested.
[0028] See Table 1 for specific test data.
[0029] Table 1
[0030]
[0031] Example 2
[0032] Take a battery from the same batch as the battery in Example 1 as sample 2, and test the initial discharge capacity of the battery of sample 2 according to the following method, and test the battery discharge capacity after charge and discharge cycles by adding only conventional electrolyte to the battery of sample 2.
[0033] (1) Conventional electrolyte preparation
[0034] The conventional electrolyte components are: a mixture of electrolyte lithium hexafluorophosphate, additives VC (vinylene carbonate), PC (propylene carbonate), and solvents EC (ethylene carbonate), EMC (ethyl methyl carbonate), and DEC (diethyl carbonate).
[0035] (2) Battery initial capacity test: At 25℃±5℃, use a 5V-20A charge and discharge tester to charge at constant current (0.75C) to a voltage of 3.65V, then charge at constant voltage to a cut-off current of 1 / 20C, leave for 30 minutes, and then discharge at constant current to a cut-off voltage of 2.5V. This is one cycle. A total of 4 cycles are performed. The average value of the test discharge battery capacity is taken as the base of the initial discharge capacity, which is calculated as 100%.
[0036] (3) Liquid injection: In a glove box, open the battery liquid injection port and inject 18 g of the conventional electrolyte prepared in step (1). After the liquid injection is completed, seal the battery, let it stand for 48 h, and then conduct a charge and discharge test on a machine.
[0037] (4) Charge and discharge test: At 25℃±5℃, use a 5V-20A charge and discharge tester to charge at constant current (0.75C) to a voltage of 3.65V, then charge at constant voltage to a cutoff current of 1 / 20C, leave for 30 minutes, and then discharge at constant current to a cutoff voltage of 2.5V. This is one cycle. The battery's initial cycle discharge capacity retention rate and the 200th cycle discharge capacity retention rate are tested.
[0038] See Table 1 for specific test data.
[0039] Example 3
[0040] Two batteries from the same batch as the batteries in Example 1 were taken as Sample 3 and Sample 4. No mixture of perfluorobutyl iodide and electrolyte, nor conventional electrolyte was added to Sample 3 and Sample 4. The initial discharge capacity of the battery and the discharge capacity of the battery after charge and discharge cycles were tested according to the following method.
[0041] (1) Battery initial capacity test: At 25℃±5℃, use a 5V-20A charge and discharge tester to charge at constant current (0.75C) to a voltage of 3.65V, then charge at constant voltage to a cutoff current of 1 / 20C, leave for 30 minutes, and then discharge at constant current to a cutoff voltage of 2.5V. This process is recorded as one cycle, and the above cycle is performed 4 times. The average value of the test discharge battery capacity is taken as the base of the initial discharge capacity, which is calculated as 100%.
[0042] (2) Charge and discharge test: At 25℃±5℃, use a 5V-20A charge and discharge tester to charge at constant current (0.75C) to a voltage of 3.65V, then charge at constant voltage to a current of 1 / 20C, leave for 30 minutes, and then discharge at constant current to a cut-off voltage of 2.5V. This process is recorded as one cycle, and the battery's initial cycle discharge capacity retention rate and the 200th cycle discharge capacity retention rate are tested.
[0043] See Table 1 for specific test data.
[0044] It should be noted that the specific calculation formula for the cycle discharge capacity retention rate is as follows:
[0045] The Nth battery discharge capacity retention rate = the Nth cycle discharge capacity of the battery / the initial discharge capacity × 100%.
[0046] The calculated data are shown in Table 1.
[0047] Sample 1 is a battery in which an electrolyte containing perfluorobutyl iodide is added, wherein the amount of perfluorobutyl iodide added is 18 g and the concentration is 1%;
[0048] Sample 2 is a battery in which only 18 g of conventional electrolyte is added;
[0049] Samples 3 and 4 are batteries in which neither perfluorobutyl iodide nor conventional electrolyte is added;
[0050] As can be seen from Table 1, the first cycle discharge capacity retention rate, the 100th cycle discharge capacity retention rate and the 200th cycle discharge capacity retention rate of the battery of sample 1 are the best, all higher than those of samples 2-sample 4. Compared with samples 3 and 4, the first discharge capacity and the 100th and 200th discharge capacities of sample 2 are almost unchanged. Therefore, it is shown that only adding electrolyte to the battery without adding perfluorobutyl iodide cannot increase the cycle discharge capacity of the battery. It also proves that adding perfluorobutyl iodide to the electrolyte can improve the physicochemical properties of the electrolyte system, improve the discharge capacity retention rate of the lithium-ion battery, and thus improve the battery cycle performance.
[0051] Example 4
[0052] Take a commercially available 24Ah lithium iron phosphate battery and directly add perfluorobutyl iodide into the battery, which improves the battery discharge capacity retention rate.
[0053] Example 5
[0054] Take a 24Ah lithium iron phosphate battery whose commercial capacity has dropped below 80%, and directly add perfluorobutyl iodide into the battery, which will increase the battery discharge capacity.
[0055] Example 6
[0056] Take a 24Ah lithium iron phosphate battery whose commercial capacity has dropped below 80%, add an electrolyte containing perfluorobutyl iodide into the battery, and the battery discharge capacity will be improved.
Claims
1. Application of perfluorobutyl iodide in lithium-ion battery electrolyte.
2. The use of perfluorobutyl iodide in a lithium ion battery electrolyte according to claim 1, characterized in that: After the lithium ion battery is formed, perfluorobutyl iodide is added.
3. The use of perfluorobutyl iodide in a lithium ion battery electrolyte according to claim 1, characterized in that: The perfluorobutyl iodide is first mixed with the electrolyte outside the lithium ion battery and then added into the electrolyte of the lithium ion battery.
4. The use of perfluorobutyl iodide in a lithium ion battery electrolyte according to claim 1, characterized in that: The perfluorobutyl iodide is directly added into the electrolyte of the lithium ion battery.
5. Application of perfluorobutyl iodide in capacity restoration of waste lithium-ion batteries.
6. The use of perfluorobutyl iodide in the capacity repair of waste lithium-ion batteries according to claim 5, characterized in that: The perfluorobutyl iodide is first mixed with the electrolyte outside the waste lithium ion battery, and then added into the electrolyte of the waste lithium ion battery.
7. The use of perfluorobutyl iodide in the capacity repair of waste lithium-ion batteries according to claim 5, characterized in that: The perfluorobutyl iodide is directly added into the electrolyte of waste lithium ion batteries.