A conductive paste applied to a high voltage battery system
By modifying the preparation method of conductive carbon materials, the problem of poor high-voltage resistance of carbon nanotube conductive paste under high voltage was solved, and safe use and improved stability under high voltage conditions were achieved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- SHENZHEN JINBAINA NANO TECH CO LTD
- Filing Date
- 2023-10-07
- Publication Date
- 2026-06-09
Smart Images
Figure BDA0004479802200000061 
Figure BDA0004479802200000071
Abstract
Description
Technical Field
[0001] This application relates to the field of conductive pastes, and more specifically, to a conductive paste for use in high-voltage battery systems. Background Technology
[0002] As fossil fuels increasingly impact the Earth's environment, clean energy is being widely adopted as an alternative. New energy batteries, a major component of clean energy, are gradually becoming the preferred choice for storing electrical energy in passenger cars, buses, and energy storage applications.
[0003] In the lithium battery field, carbon nanotubes, with their superior conductivity, are widely used by lithium battery manufacturers as a novel conductive agent to improve the energy density and cycle life of lithium batteries. The rapid development of new energy vehicles and the increasing energy density of power lithium batteries will accelerate the replacement of traditional conductive agents, inevitably driving a rapid increase in demand for carbon nanotube conductive slurry products.
[0004] For example, patent CN110491546A discloses a carbon nanotube conductive material and its preparation method. The carbon nanotube conductive slurry comprises the following components by mass percentage: 0.1–0.5% first carbon nanotubes, 0.1–1% second carbon nanotubes, 0.1–5.2% dispersant, 0.5–4% binder, and the balance being solvent. The first carbon nanotubes have a length of 100–300 μm and a diameter of 5–40 nm; the second carbon nanotubes have a length of 10–20 μm and a diameter of 30–100 nm. The carbon nanotube conductive slurry also includes 0.1–1% carbon black. Although the prepared carbon nanotube conductive slurry exhibits good conductivity, when applied to lithium-ion batteries, it can only be used at voltages of 3.0–4.2V, indicating poor high-voltage performance. Summary of the Invention
[0005] To effectively improve the high voltage resistance of products and enable them to be used safely under high voltage conditions, this application provides a conductive paste for use in high voltage battery systems.
[0006] The conductive paste for high-voltage battery systems provided in this application adopts the following technical solution:
[0007] A conductive paste for use in high-voltage battery systems comprises the following raw materials in parts by weight: 3-10 parts of modified conductive carbon material, 1-3 parts of polyvinylpyrrolidone, 90-95 parts of N-methylpyrrolidone, and 3-7 parts of a polymer containing alcohol hydroxyl groups.
[0008] The modified conductive carbon material is prepared by the following steps: magnesium aluminum silicate is uniformly dispersed in a coupling agent to obtain a dispersion; the conductive carbon material and activator are subjected to water bath ultrasonic treatment, filtered and dried, and then the dispersion is added and microwaved.
[0009] By optimizing the composition of the conductive paste and further using modified conductive paste, polymers containing alcohol hydroxyl groups, polyvinylpyrrolidone and N-methylpyrrolidone in combination, the resulting conductive paste not only has good conductivity, but can also be used safely under high voltage conditions exceeding 4.2V.
[0010] Conductive carbon materials are activated and modified using an activator and ultrasonic treatment. A dispersion formed from magnesium aluminum silicate and a coupling agent is then applied under microwave conditions. Magnesium aluminum silicate adheres to and fills the conductive carbon material, while the coupling agent further modifies its surface, promoting compatibility among the components. The resulting modified conductive carbon material exhibits excellent dispersibility, reducing agglomeration and ensuring uniform dispersion within the system. Furthermore, the modified conductive carbon material filled with magnesium aluminum silicate forms a stable three-dimensional conductive network with the hydroxyl groups in the alcohol-containing polymer through group and intermolecular forces. This network provides excellent conductivity in battery products. The modified conductive carbon material also exhibits good suspension and stability within the system, enabling safe use under high voltage conditions and improving the product's high-voltage resistance.
[0011] Furthermore, the conductive carbon material is any one of carbon nanotubes, graphite, and carbon black.
[0012] Furthermore, the conductive carbon material is carbon nanotubes, and the diameter of the carbon nanotubes is 5-12 nm, for example, 5 nm, 6.5 nm, 7 nm, 8 nm, 9 nm, 12 nm, etc. The carbon nanotubes can be single-walled carbon nanotubes or multi-walled carbon nanotubes.
[0013] As a further preferred technical solution, multi-walled carbon nanotubes are selected.
[0014] Carbon nanotubes exhibit excellent electric double-layer effect. Compared with carbon materials such as graphite and carbon black, they have better electrical conductivity and structural stability, higher strength, and better mechanical properties, which have a positive effect on improving battery capacity and battery cycle life.
[0015] Furthermore, the activator is at least one of nitric acid, hydrochloric acid, and acetic acid.
[0016] As a further preferred technical solution, the mass concentration of nitric acid is 20%, the mass concentration of hydrochloric acid is 25%, and the mass concentration of acetic acid is 30%.
[0017] Furthermore, the activator can be nitric acid, hydrochloric acid, or acetic acid, or a combination of nitric acid and hydrochloric acid, or a combination of hydrochloric acid and acetic acid, or a combination of nitric acid and acetic acid.
[0018] As a further preferred technical solution, an activator is prepared by mixing nitric acid and acetic acid in a 1:1 weight ratio. Activating conductive carbon materials using a mixture of organic and inorganic acids can further improve the activation effect.
[0019] Furthermore, the coupling agent is selected from any one of KH-550, KH-560, and KH-570.
[0020] Furthermore, the polymer containing alcohol hydroxyl groups is polyethylene glycol and / or polyvinyl alcohol.
[0021] Furthermore, the polymer containing alcohol hydroxyl groups can be polyethylene glycol 400 or an aqueous solution of polyvinyl alcohol.
[0022] As a further preferred option, the polymer containing alcohol hydroxyl groups is obtained by compounding polyethylene glycol 400 and polyvinyl alcohol in a weight ratio of 1:(0.5-1).
[0023] Polymers containing hydroxyl groups can not only adjust the viscosity of the system to a certain extent, but also combine with modified conductive carbon materials to form a stable three-dimensional conductive network through the interaction of groups and molecules. When used in battery products, they can play an excellent conductive role. Experimental research has found that when polyethylene glycol 400 and polyvinyl alcohol are compounded in a weight ratio of 1:(0.5-1), the product performance is better.
[0024] Furthermore, the components used in the modified conductive carbon material are as follows, by weight: 2-6 parts conductive carbon material, 10-20 parts activator, 1-3 parts coupling agent, and 0.5-1.5 parts magnesium aluminum silicate.
[0025] Optimizing the component dosage of modified conductive carbon materials can further improve the modification effect of conductive carbon materials and help improve the viscosity of conductive slurry, so that the obtained conductive slurry not only has good conductivity, but can also be used safely under high voltage conditions exceeding 4.2V, with excellent high voltage resistance.
[0026] Furthermore, in the preparation steps of the modified conductive carbon material, the ultrasonic treatment specifically includes: ultrasonic power of 1000-1500W, ultrasonic time of 1-4min, stirring rate of 300-500r / min, and water bath temperature of 70-90℃. Specifically, the ultrasonic power can be 1000W, 1100W, 1250W, 1350W, 1400W, 1500W, etc., and the stirring rate can be 300r / min, 350r / min, 450r / min, etc.
[0027] Furthermore, in the preparation steps of the modified conductive carbon material, the microwave treatment specifically involves electromagnetic waves of 50-150 GHz at a temperature of 40-60℃.
[0028] By performing ultrasonic treatment simultaneously with acidification of carbon nanotubes, the surface of the carbon nanotubes can be further modified, which facilitates the uniform filling and adsorption of magnesium aluminum silicate on the surface of the carbon nanotubes under the action of microwaves, thereby improving their apparent structure.
[0029] The prepared modified conductive carbon material, polyvinylpyrrolidone, N-methylpyrrolidone and the polymer containing alcohol hydroxyl groups are mixed evenly by high-speed stirring to obtain a conductive slurry for use in high-voltage battery systems. The stirring speed is generally 500-800 r / min, and as a further preferred technical solution, the stirring speed is 800 r / min.
[0030] In summary, this application has the following beneficial effects:
[0031] 1. Conductive carbon materials are activated and modified using an activator and ultrasonic treatment. The dispersion formed by magnesium aluminum silicate and a coupling agent, under microwave conditions, allows magnesium aluminum silicate to adhere to and fill the conductive carbon material. The coupling agent further modifies the surface of the conductive carbon material, promoting compatibility between the raw material components. The resulting modified conductive carbon material exhibits excellent dispersibility, reducing agglomeration and ensuring uniform dispersion within the system. Furthermore, the conductive carbon material filled with magnesium aluminum silicate can form a stable three-dimensional conductive network with the hydroxyl groups in the alcohol-containing polymer through group and intermolecular forces. This provides excellent conductivity in battery products. The modified conductive carbon material also exhibits good suspension and stability within the system, enabling safe use under high voltage conditions and improving the product's high-voltage resistance.
[0032] 2. This application modifies conductive carbon materials and further uses modified conductive carbon materials, alcohol-containing polymers and N-methylpyrrolidone in combination to obtain conductive pastes that not only have good conductivity but can also be used safely under high voltage conditions exceeding 4.2V. Detailed Implementation
[0033] The embodiments of the present invention will be described in detail below with reference to the examples. However, those skilled in the art will understand that the following examples are only for illustrating the present invention and should not be regarded as limiting the scope of the present invention. Specific conditions not specified in the examples shall be carried out according to conventional conditions or conditions recommended by the manufacturer. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.
[0034] Example of preparation of modified conductive carbon materials
[0035] Preparation Example 1
[0036] The modified conductive carbon material was prepared by the following steps: 0.5g of magnesium aluminum silicate was uniformly dispersed in 1g of coupling agent KH-570 to obtain a dispersion. 2g of graphite and 10g of hydrochloric acid solution were subjected to ultrasonic treatment in a water bath. The ultrasonic conditions were: ultrasonic power 1000w, ultrasonic time 4min, stirring rate 300r / min, and water bath temperature 70℃. The mixture was then filtered and dried at 35℃. The dispersion was then added and microwaved at 50GHz electromagnetic waves and 60℃ for 10min.
[0037] Preparation Example 2
[0038] The modified conductive carbon material was prepared by the following steps: 1.5g of magnesium aluminum silicate was uniformly dispersed in 3g of coupling agent KH-560 to obtain a dispersion. 6g of carbon black and 20g of nitric acid solution were subjected to ultrasonic treatment in a water bath. The ultrasonic conditions were: ultrasonic power 1500w, ultrasonic time 1min, stirring speed 400r / min, and water bath temperature 90℃. The mixture was then filtered and dried at 35℃. The dispersion was then added and microwaved at 150GHz electromagnetic waves and 40℃ for 8min.
[0039] Preparation Example 3
[0040] The modified conductive carbon material was prepared by the following steps: 1g of magnesium aluminum silicate was uniformly dispersed in 2g of coupling agent KH-550 to obtain a dispersion. 5g of carbon nanotubes and 16g of activator were subjected to water bath ultrasonic treatment. The activator was a mixture of nitric acid solution and acetic acid solution in a weight ratio of 1:1. The water bath ultrasonic conditions were: ultrasonic power 1200w, ultrasonic time 3min, stirring rate 500r / min, and water bath temperature 80℃. The mixture was then filtered and dried at 35℃. The dispersion was then added and microwaved at 100GHz electromagnetic waves and 50℃ for 8min.
[0041] Preparation Example 4
[0042] The difference from Preparation Example 3 is that the amount of components is different. Specifically, magnesium aluminum silicate 2g, activator 5g, coupling agent 0.5g, carbon nanotubes 8g, and the rest are the same as Preparation Example 3.
[0043] Preparation Example 5
[0044] The difference from Preparation Example 3 is that the activator is a sulfuric acid solution and a hydrochloric acid solution in a weight ratio of 1:4, while the rest are the same as Preparation Example 3.
[0045] Comparative Preparation Example 1
[0046] The difference from Preparation Example 3 is that magnesium aluminum silicate is not added to the modified conductive carbon material, but otherwise it is the same as Preparation Example 3.
[0047] Comparative Preparation Example 2
[0048] The difference from Preparation Example 3 is that the modified conductive carbon material is prepared by the following steps: magnesium aluminum silicate is uniformly dispersed in a coupling agent to obtain a dispersion, carbon nanotubes and activator are heated in a water bath to 80°C for 3 min, then filtered and dried at 35°C, and then the dispersion is added and stirred to obtain the modified conductive carbon material; the amount of raw material components is the same as that in Preparation Example 3.
[0049] Comparative preparation example 3
[0050] The difference from Preparation Example 3 is that the modified conductive carbon material was prepared by the following steps: carbon nanotubes and coupling agent were ultrasonically dispersed with an ultrasonic power of 1200 W, an ultrasonic time of 3 min, and a stirring rate of 500 r / min to obtain the modified conductive carbon material; the amount of raw material components was the same as that in Preparation Example 3.
[0051] Example
[0052] Example 1
[0053] High-voltage resistant carbon nanotube conductive paste comprises the following raw materials: 3g of modified conductive carbon material prepared in Example 1, 3g of polyvinylpyrrolidone, 90g of N-methylpyrrolidone, and 7g of polyethylene glycol.
[0054] Example 2
[0055] High-voltage resistant carbon nanotube conductive paste comprises the following raw materials: 10g of modified conductive carbon material prepared in Example 1, 1g of polyvinylpyrrolidone, 95g of N-methylpyrrolidone, and 3g of diethylene glycol.
[0056] Example 3
[0057] A high-voltage resistant carbon nanotube conductive paste comprises the following raw materials: 8g of modified conductive carbon material prepared in Example 1, 2g of polyvinylpyrrolidone, 93g of N-methylpyrrolidone, and 5g of polyvinyl alcohol.
[0058] Example 4
[0059] The difference from Example 3 is that the polymer containing alcohol hydroxyl groups is a 1:1 weight ratio of polyethylene glycol 400 and polyvinyl alcohol solution, while the rest is the same as in Example 3.
[0060] Example 5
[0061] The difference from Example 3 is that the polymer containing hydroxyl groups is a solution of polyethylene glycol 400 and polyvinyl alcohol in a weight ratio of 1:4, while the rest is the same as in Example 3.
[0062] Example 6
[0063] The difference from Example 4 is that the modified conductive carbon material prepared in Preparation Example 2 was used, while all other aspects are the same as in Example 4.
[0064] Example 7
[0065] The difference from Example 4 is that the modified conductive carbon material prepared in Preparation Example 3 was used, while all other aspects are the same as in Example 4.
[0066] Example 8
[0067] The difference from Example 4 is that the modified conductive carbon material prepared in Example 4 was used, while the rest are the same as in Example 4.
[0068] Example 9
[0069] The difference from Example 4 is that the modified conductive carbon material prepared in Preparation Example 5 was used, while all other aspects are the same as in Example 4.
[0070] Comparative Example
[0071] Comparative Example 1
[0072] The difference from Example 7 is that the modified conductive carbon material prepared in Comparative Preparation Example 1 was used, while all other aspects are the same as in Example 7.
[0073] Comparative Example 2
[0074] The difference from Example 7 is that the modified conductive carbon material prepared in Comparative Preparation Example 2 was used, while all other aspects are the same as in Example 7.
[0075] Comparative Example 3
[0076] The difference from Example 7 is that the modified conductive carbon material prepared in Comparative Preparation Example 3 was used, while all other aspects are the same as in Example 7.
[0077] Comparative Example 4
[0078] The difference from Example 7 is that the polymer containing alcohol hydroxyl groups is replaced with an equal amount of ethanol, while the rest is the same as in Example 7.
[0079] Performance testing
[0080] The conductive pastes obtained in Examples 1-9 and Comparative Examples 1-4 were assembled into lithium batteries using conventional methods in the art. Each battery was labeled with the corresponding conductive paste used, and the maximum operating voltage of each battery was tested (the voltage at which the conductive paste does not oxidize and decompose after 100 cycles at the maximum operating voltage, ensuring that the battery does not experience thermal runaway). The test results are shown in Table 1.
[0081] The batteries assembled from the conductive pastes obtained in Examples 1-9 and Comparative Examples 1-4 were subjected to cycle performance tests, including 0.5C charging / 0.5C discharging (the charging and discharging process was carried out within the maximum charging and discharging voltage range of each battery), and the capacity retention rate after 150 cycles. The results are shown in Table 1.
[0082] Table 1
[0083]
[0084]
[0085] As can be seen from Examples 1-9 and Table 1, the conductive paste obtained in this application can be used safely under high voltage conditions of 4.3V-5.0V, and the capacity retention rate after 150 cycles is as high as 95% or more, indicating excellent product quality.
[0086] As can be seen from Example 7 and Comparative Examples 1-3, and Table 1, the quality of the modified conductive carbon material is poor regardless of whether the raw material components or the corresponding processing steps are lacking. This results in a significant decrease in the maximum operating voltage of the battery and a noticeable decrease in cycle capacity retention. This is because after the conductive carbon material is activated and modified using an activator and ultrasonic treatment, under microwave conditions, the dispersion formed by magnesium aluminum silicate and the coupling agent further modifies the surface of the conductive carbon material. Magnesium aluminum silicate can adhere to and fill the conductive carbon material, and the coupling agent can promote the compatibility between the raw material components. The resulting modified conductive carbon material has excellent dispersibility, reduces the agglomeration of conductive carbon materials, and allows it to be uniformly dispersed in the system. Furthermore, the conductive carbon material filled with magnesium aluminum silicate can form a stable three-dimensional conductive network with the hydroxyl groups in the alcohol-containing polymer through group and intermolecular forces. This network provides excellent conductivity in battery products. Moreover, the modified conductive carbon material has good suspension and stability in the system, enabling the product to be used safely under high voltage conditions and improving the high voltage resistance of the product.
[0087] As can be seen from Example 7 and Comparative Example 4, and Table 1, replacing the polymer containing hydroxyl groups with ethanol reduces the stability and conductivity of the conductive paste, decreases the maximum operating voltage of the product, and significantly reduces the cycle capacity retention of the battery.
[0088] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.
Claims
1. A conductive paste for use in high-voltage battery systems, characterized in that, The raw materials include the following parts by weight: 3-10 parts of modified conductive carbon material, 1-3 parts of polyvinylpyrrolidone, 90-95 parts of N-methylpyrrolidone, and 3-7 parts of polymer containing alcohol hydroxyl groups. The modified conductive carbon material is prepared by the following steps: magnesium aluminum silicate is uniformly dispersed in a coupling agent to obtain a dispersion; the conductive carbon material and activator are subjected to water bath ultrasonic treatment, filtered and dried, and then the dispersion is added and microwaved.
2. The conductive paste for high-voltage battery systems according to claim 1, characterized in that: The conductive carbon material is any one of carbon nanotubes, graphite, and carbon black.
3. The conductive paste for high-voltage battery systems according to claim 2, characterized in that: The conductive carbon material is a carbon nanotube with a diameter of 5-12 nm.
4. The conductive paste for high-voltage battery systems according to claim 1, characterized in that: The activator is at least one of nitric acid, hydrochloric acid, and acetic acid.
5. The conductive paste for high-voltage battery systems according to claim 1, characterized in that: The coupling agent is selected from any one of KH-550, KH-560, and KH-570.
6. The conductive paste for use in high-voltage battery systems according to any one of claims 1-5, characterized in that: The modified conductive carbon material is prepared using the following components in parts by weight: 2-6 parts conductive carbon material, 10-20 parts activator, 1-3 parts coupling agent, and 0.5-1.5 parts magnesium aluminum silicate.
7. The conductive paste for high-voltage battery systems according to claim 1, characterized in that: The polymer containing alcohol hydroxyl groups is polyethylene glycol and / or polyvinyl alcohol.
8. The conductive paste for high-voltage battery systems according to claim 6, characterized in that: In the preparation steps of the modified conductive carbon material, the ultrasonic treatment specifically includes: ultrasonic power of 1000-1500w, ultrasonic time of 1-4min, stirring rate of 300-500r / min, and water bath temperature of 70-90℃.
9. The conductive paste for high-voltage battery systems according to claim 6, characterized in that: In the preparation steps of modified conductive carbon materials, the microwave treatment specifically involves electromagnetic waves of 50-150 GHz at a temperature of 40-60℃.