Use of 2-cyanothiazoles
By adding 2-cyanthiazole as an electrolyte additive to lithium-ion batteries, the problem of limited improvement in circulation performance of lithium-ion batteries is solved, and the capacity repair of old batteries and the performance improvement of new batteries is achieved, reducing the cost of use.
Patent Information
- Application Number
- CN202410149569.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-02-02
- Publication Date
- 2025-08-05
AI Technical Summary
The circulation performance of existing lithium-ion batteries is limited, resulting in the battery discharge capacity dropping to 98.5% at about 70 times. After thousands of cycles, it is greatly reduced and cannot be used. It is urgent to effectively slow down the attenuation rate of discharge capacity to reduce the cost of use.
Add 2-cyanthiazole as an electrolyte additive to the lithium-ion battery. By mixing it with the electrolyte, the battery can be repaired and the discharge capacity retention rate of the new battery is improved.
By adding 2-cyanthiazole, the discharge capacity drop rate of the old lithium-ion battery is delayed, the discharge capacity retention rate is improved, the cost of use is reduced, the old battery is reusable, and the battery circulation performance is improved.
Smart Images
Figure CN120432640A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of lithium ion batteries, in particular to the application of 2-cyanothiazole in capacity restoration of old lithium ion batteries and in lithium ion battery electrolytes. Background Art
[0002] With the increasing emphasis on environmental protection worldwide, the status of lithium-ion batteries as an important clean energy source in the power industry and 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 vehicles and automobiles.
[0003] Currently, whether in energy storage or automotive power, improving the cycle performance of lithium-ion batteries, while maintaining a relatively stable battery energy density, is fundamental to reducing the cost of using lithium-ion batteries and improving user satisfaction. Lithium-ion batteries primarily consist of a housing, positive and negative electrodes, a separator, and an electrolyte. Existing literature and patents have disclosed methods for improving the cycle performance of lithium-ion batteries by focusing on the positive and negative electrode materials, as well as the electrolyte.
[0004] In terms of electrolyte, by adding additives to the electrolyte, the attenuation rate of the lithium-ion battery discharge capacity can be effectively slowed down and the cycle performance of the lithium-ion battery can be improved. However, the current additives have limited improvement on the cycle performance of lithium-ion batteries. After about 70 cycles, the battery's discharge capacity drops from 100% to about 98.5%; after several thousand cycles, the battery's discharge capacity 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 repair the discharge capacity of old batteries so that old batteries can be used again.
[0007] One of the purposes of the present invention is to provide an application of 2-cyanothiazole in the capacity restoration of old lithium-ion batteries.
[0008] Furthermore, the 2-cyanothiazole is first mixed with the electrolyte outside the old lithium-ion battery and then added into the old lithium-ion battery.
[0009] Furthermore, the 2-cyanothiazole is directly added into the old lithium-ion battery.
[0010] Another object of the present invention is to provide the use of 2-cyanothiazole in lithium ion battery electrolyte.
[0011] Furthermore, after the lithium-ion battery is formed, 2-cyanothiazole is added.
[0012] Furthermore, the 2-cyanothiazole is first mixed with the electrolyte outside the lithium-ion battery and then added into the lithium-ion battery.
[0013] Furthermore, the 2-cyanothiazole is directly added into the electrolyte of the lithium-ion battery.
[0014] The present invention has the following advantages and effects:
[0015] The present invention realizes effective restoration of the capacity of the old lithium ion battery by adding 2-cyanothiazole or an electrolyte containing 2-cyanothiazole into the old lithium ion battery.
[0016] Furthermore, the rate of decrease in discharge capacity of repaired old lithium-ion batteries is slower than that before repair, thereby effectively improving the discharge capacity retention rate of old lithium-ion batteries, reducing the use cost of lithium-ion batteries, and allowing old batteries to be reused, which is economical and environmentally friendly.
[0017] The present invention adds 2-cyanothiazole to the electrolyte of a new lithium-ion battery, thereby slowing down the rate of decrease in the discharge capacity of the lithium-ion battery, thereby effectively improving the cycle performance of the battery and reducing the use cost of the lithium-ion battery. BRIEF DESCRIPTION OF THE DRAWINGS
[0018] Figure 1 This is a comparison chart of the battery cycle-discharge capacity retention rates of Examples 1 to 3. DETAILED DESCRIPTION
[0019] 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 embodiments described 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 making creative efforts are within the scope of protection of the present invention.
[0020] The old lithium-ion battery in the embodiment refers to an old battery that has been used and whose discharge capacity has dropped to about 95% or below of the nominal capacity.
[0021] The following is a detailed description of the application of 2-cyanothiazole in the electrolyte of used lithium-ion batteries through Examples 1-3.
[0022] It should be noted that 2-cyanothiazole, also known as 2-thiazolecarbonitrile, is an organic compound containing a thiazole ring and a cyano functional group. Its CAS number is 1452-16-0, molecular weight is 110, molecular formula is C₄H₂N₂S, density is 1.3±0.1 g / cm₃, and boiling point is 202.5±23.0°C. 2-Cyanothiazole can be used as an intermediate in the preparation of pharmaceuticals such as antibacterial, antitumor, and antiviral drugs; it is also used in the preparation of pesticides such as herbicides and fungicides. This invention proposes for the first time that 2-cyanothiazole be added to old lithium batteries as an electrolyte additive to restore their capacity to a certain extent, improving their cycle life. It can also be added to new batteries to increase their capacity. To fully demonstrate this effect of 2-cyanothiazole, the present invention provides several examples to demonstrate this effect.
[0023] Example 1
[0024] Two commercially available used lithium iron phosphate batteries with a nominal capacity of 20 Ah were taken as Samples 1 and Sample 2 in Example 1 (after testing, the initial discharge capacity of the batteries of Sample 1 and Sample 2 was 92.65% and 93.55% of the nominal capacity). First, the initial discharge capacity of the battery was tested, and then electrolyte No. 1 containing 2-cyanothiazole was added to the batteries of Sample 1 and Sample 2 in a glove box. Then, the discharge capacity after charge and discharge cycles was tested, and finally the discharge capacity retention rate of the battery was calculated.
[0025] (1) Preparation of electrolyte No. 1 containing additives: Electrolyte No. 1 was prepared in a glove box. The concentration of lithium hexafluorophosphate in the prepared electrolyte was 1 mol / L. The composition of the additives and solvent is shown in Table 1.
[0026] (2) Battery initial capacity test: At 25℃±5℃, use a 5V-40A charge and discharge tester to charge at a constant current (40A) to a voltage of 3.65V, then charge at a constant voltage of 3.65V to a cut-off current of 1.2A, leave it for 10 minutes, then discharge at a constant current of 40A to a voltage of 2.5V, and leave it for another 10 minutes. This is one cycle. A total of 10 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%.
[0027] (3) Liquid injection: In a glove box, open the battery injection port and inject the electrolyte containing 2-cyanothiazole prepared in step (1). The amount of electrolyte containing additives added is shown in Table 2. After the injection is completed, seal the battery, let it stand for 48 hours, and then conduct a charge and discharge test on the machine.
[0028] (4) Charge and discharge test: At 25℃±5℃, use a 5V-40A charge and discharge tester to charge at a constant current (40A) to a voltage of 3.65V, then charge at a constant voltage of 3.65V to a cutoff current of 1.2Ah, leave it for 10 minutes, then discharge at a constant current of 40A to a cutoff voltage of 2.5V, and leave it for another 10 minutes. This is one cycle. The battery discharge capacity at the 10th, 50th, 100th, 150th, 200th, 250th and 300th cycle is tested, and the capacity retention rate is calculated.
[0029] See Table 2 for specific test data.
[0030] Example 2
[0031] Two used lithium iron phosphate batteries with a nominal capacity of 20 Ah purchased from the same batch as the batteries in Example 1 were taken as Comparative Samples 1 and Comparative Sample 2 (after testing, the initial discharge capacities of the Comparative Samples 1 and Comparative Sample 2 batteries were 95.05% and 94.00% of the nominal capacity). No 2-cyanothiazole or any electrolyte was added to the Comparative Samples 1 and Comparative Sample 2 batteries. The initial discharge capacity of the Comparative Samples 1 and Comparative Sample 2 batteries, as well as the battery discharge capacity after charge and discharge cycles were tested according to the following method.
[0032] (1) Battery initial capacity test: At 25℃±5℃, use a 5V-40A charge and discharge tester to charge at a constant current (40A) to a voltage of 3.65V, then charge at a constant voltage of 3.65V to a cut-off current of 1.2A, leave it for 10 minutes, then discharge at a constant current of 40A to a voltage of 2.5V, and leave it for another 10 minutes. This is one cycle. A total of 10 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%.
[0033] (2) Charge and discharge test: At 25℃±5℃, use a 5V-40A charge and discharge tester to charge at a constant current (40A) to a voltage of 3.65V, then charge at a constant voltage of 3.65V to a cutoff current of 1.2Ah, leave it for 10 minutes, then discharge at a constant current of 40A to a cutoff voltage of 2.5V, and leave it for another 10 minutes. This is one cycle. The battery discharge capacity at the 10th, 50th, 100th, 150th, 200th, 250th and 300th cycle is tested, and the capacity retention rate is calculated.
[0034] See Table 2 for specific test data.
[0035] Example 3
[0036] Take two used lithium iron phosphate batteries with a nominal capacity of 20Ah purchased from the same batch as the batteries in Example 1 as comparison samples 3 and comparison sample 4 (after testing, the initial discharge capacity of the comparison sample 3 and comparison sample 4 batteries was 93.30% and 94.25% of the nominal capacity). First, test the initial discharge capacity of the comparison sample 3 and comparison sample 4 batteries according to the following method, then add electrolyte No. 2 to the comparison sample 3 and comparison sample 4 batteries in a glove box, then test the battery discharge capacity after charge and discharge cycles, and finally calculate the capacity retention rate.
[0037] (1) Preparation of electrolyte No. 2: Electrolyte No. 2 was prepared in a glove box. The concentration of lithium hexafluorophosphate in the prepared electrolyte No. 2 was 1 mol / L. The composition of the solvent was shown in Table 1.
[0038] (2) Battery initial capacity test: At 25℃±5℃, use a 5V-40A charge and discharge tester to charge at a constant current (40A) to a voltage of 3.65V, then charge at a constant voltage of 3.65V to a cut-off current of 1.2A, leave it for 10 minutes, then discharge at a constant current of 40A to a voltage of 2.5V, and leave it for another 10 minutes. This is one cycle. A total of 10 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%.
[0039] (3) Liquid injection: In the glove box, open the battery injection port and inject the electrolyte No. 2 prepared in step (1). The injection amount is shown in Table 2. After the injection is completed, seal the battery, let it stand for 48 hours, and then conduct the charge and discharge test on the machine.
[0040] (4) Charge and discharge test: At 25℃±5℃, use a 5V-40A charge and discharge tester to charge at a constant current (40A) to a voltage of 3.65V, then charge at a constant voltage of 3.65V to a cutoff current of 1.2Ah, leave it for 10 minutes, then discharge at a constant current of 40A to a cutoff voltage of 2.5V, and leave it for another 10 minutes. This is one cycle. The battery discharge capacity at the 10th, 50th, 100th, 150th, 200th, 250th and 300th cycle is tested, and the capacity retention rate is calculated.
[0041] See Table 2 for specific test data.
[0042] It should be noted that the specific calculation formula for the cycle discharge capacity retention rate is as follows:
[0043] The Nth battery discharge capacity retention rate = the Nth cycle discharge capacity of the battery / the initial discharge capacity before adding electrolyte × 100%.
[0044] The calculated data are shown in Table 2.
[0045] Electrolyte No. 1 containing 2-cyanothiazole was added to the batteries of Samples 1 and 2 in amounts of 12.46 g and 13.55 g, respectively, and the concentration of 2-cyanothiazole in the batteries was 5%.
[0046] No electrolyte or additives were added to the batteries of Comparative Samples 1 and 2.
[0047] Electrolyte No. 2 was added to the batteries of Comparative Samples 3 and 4, and Electrolyte No. 2 did not contain the 2-cyanothiazole additive.
[0048] Both electrolyte No. 1 and electrolyte No. 2 were prepared from EC (ethylene carbonate) and MC (ethyl methyl carbonate) in a mass ratio of 3:7, and the concentration of lithium hexafluorophosphate therein was 1 mol / L. The difference was that electrolyte No. 1 contained the additive 2-cyanothiazole, while electrolyte No. 2 did not contain the additive 2-cyanothiazole. Therefore, the only difference between the electrolytes added to the battery of Example 1 and the battery of Example 3 was the addition of the additive 2-cyanothiazole to the electrolyte added to the battery of Example 1.
[0049] From Table 2 and Figure 1 It can be seen that the capacity of the battery fluctuates greatly in the first 50 charge and discharge cycles. The 50th, 100th, 150th, 200th, 250th and 300th cycle discharge capacity retention rates of sample 1 and sample 2 batteries are higher than the 50th, 100th, 150th, 200th, 250th and 300th cycle discharge capacity retention rates of comparison sample 1, comparison sample 2, comparison sample 3 and comparison sample 4 batteries. Sample 1 and sample 2 are not only higher than the battery without any electrolyte in Example 2, but also higher than the battery with electrolyte No. 2 containing no 2-cyanothiazole in Example 3. Therefore, it is explained that adding an electrolyte containing 2-cyanothiazole to the battery can increase the cycle discharge capacity of the battery, has the effect of improving the discharge capacity retention rate of the lithium-ion battery, delaying battery attenuation, and thus improving the battery life.
[0050] Comparative Samples 3 and 4 were added with Electrolyte No. 2, but no 2-cyanothiazole additive was added to Electrolyte No. 2. The discharge retention rates at the 10th, 50th, 100th, 150th, 200th, 250th, and 300th cycles were not significantly improved compared to Comparative Samples 1 and 2, indicating that the addition of only electrolyte without the additive 2-cyanothiazole did not significantly improve the battery's cycle capacity and could not slow down the battery's attenuation rate. The discharge capacity retention rates of Samples 1 and 2 at the 50th, 100th, 150th, 200th, 250th, and 300th cycles were higher than those of all comparative samples, indicating that the addition of 2-cyanothiazole to the electrolyte improved the battery's capacity retention rate, slowed down the battery's attenuation rate, and thus increased the battery's service life.
[0051] Table 1 Composition of electrolyte solvents and additives (mass fraction)
[0052] serial number EC EMC 2-Cyanothiazole Electrolyte No. 1 3 7 5 Electrolyte No. 2 3 7 0
[0053] Table 2 Capacity retention of batteries at different cycle times
[0054]
[0055] Example 4
[0056] Take a new 20Ah lithium iron phosphate battery available on the market, directly add 2-cyanothiazole into the battery, and the battery discharge capacity retention rate is improved.
[0057] Example 5
[0058] Take a new 20Ah lithium iron phosphate battery available on the market, add an electrolyte containing 2-cyanothiazole into the battery, and the battery discharge capacity will be improved.
Claims
Application of 1.2-cyanothiazole in capacity restoration of old lithium-ion batteries.
2. The use of 2-cyanothiazole in the capacity restoration of old lithium-ion batteries according to claim 1, characterized in that: The 2-cyanothiazole is first mixed with the electrolyte outside the old lithium ion battery and then added into the electrolyte of the old lithium ion battery.
3. The use of 2-cyanothiazole according to claim 1 in the capacity restoration of old lithium-ion batteries, characterized in that: The 2-cyanothiazole was added directly to old lithium-ion batteries.
4. Application of 2-cyanothiazole in lithium-ion battery electrolyte.
5. The use of 2-cyanothiazole in a lithium-ion battery electrolyte according to claim 4, characterized in that: After the lithium ion battery is formed, 2-cyanothiazole is added.
6. The use of 2-cyanothiazole in a lithium-ion battery electrolyte according to claim 4, characterized in that: The 2-cyanothiazole is first mixed with an electrolyte outside the lithium ion battery and then added into the lithium ion battery.
7. The use of 2-cyanothiazole in a lithium-ion battery electrolyte according to claim 4, characterized in that: The 2-cyanothiazole is directly added into the electrolyte of the lithium ion battery.