New energy lithium battery lamination process

Abstract

The invention relates to the technical field of battery manufacturing, and discloses a new energy lithium battery lamination process, which comprises the following steps: respectively mixing a positive electrode material and a negative electrode material with corresponding electrolyte solutions under different conditions, and fully stirring to form positive electrode material slurry and negative electrode material slurry; the preparation method comprises the following steps: respectively coating stirred positive and negative electrode material slurry on corresponding aluminum foil and copper foil to form a positive electrode plate and a negative electrode plate, carrying out die cutting and slitting on the dried electrode plates to obtain required sizes and shapes, selecting a diaphragm material, carrying out pre-treatment work of static electricity removal, and carrying out active continuous unwinding technology to obtain the lithium ion battery. High-speed continuous active unwinding is realized through intelligent control, a linear motor module is used for transferring electrode plates and diaphragms to a lamination position, unwinding is started, positive plates, diaphragms and negative plates are alternately stacked on a lamination table to form a multi-layer lamination structure, pre-charging and pre-discharging testing is performed on a laminated battery cell, and the performance and safety of the battery cell are detected. And packaging the qualified battery cell to prepare the battery.

Description

Technical Field

[0001] The present invention relates to the technical field of battery manufacturing, and in particular to a new energy lithium battery lamination process. Background Art

[0002] In the lamination process of new energy lithium batteries, diaphragm tension control is a crucial technical link. This process not only affects the performance of the battery, but is also directly related to the safety and service life of the battery.

[0003] During the lamination process, the separator tension control is crucial. When the tension is too large, the separator is prone to deformation or even tearing, resulting in frequent breakages during the production process and reduced production efficiency. When the tension is too small, the separator is prone to wrinkling and shrinking, resulting in the separator stacking deviation during lamination, which in turn affects the overall performance and safety of the battery. Therefore, precise control of the separator tension is one of the key factors to ensure battery quality. Summary of the invention

[0004] 1. Technical issues to be resolved

[0005] In view of the deficiencies in the prior art, the present invention provides a new energy lithium battery lamination process, which has the advantage of being able to accurately control the diaphragm tension, and solves the problem in the prior art that the diaphragm tension cannot be accurately controlled.

[0006] (II) Technical solution

[0007] To achieve the above object, the present invention provides the following technical solution: a new energy lithium battery lamination process, comprising the following steps:

[0008] Step 1: Mixing the positive electrode material and the negative electrode material with the corresponding electrolyte solution under different conditions, and stirring them fully to form positive and negative electrode material slurries;

[0009] Step 2: coating and drying: coating the stirred positive and negative electrode material slurries on the corresponding aluminum foil and copper foil to form positive and negative electrode sheets;

[0010] Step 3: Die-cutting and slitting: Die-cut and slitting the dried electrode to obtain the required size and shape;

[0011] Step 4: Diaphragm preparation: Select the diaphragm material and perform pretreatment to remove static electricity;

[0012] Step 5. Set unwinding parameters: Use active continuous unwinding technology to achieve high-speed continuous active unwinding through intelligent control;

[0013] Step 6: Transfer: Use the linear motor module to transfer the electrode sheet and the diaphragm to the stacking position;

[0014] Step 7: Automatic lamination: Start unwinding, and alternately stack the positive electrode sheet, the separator, and the negative electrode sheet on the lamination table to form a multi-layer lamination structure;

[0015] Step 8: Pre-charge and discharge test: Perform pre-charge and discharge test on the stacked cells to detect their performance and safety;

[0016] Step 9: Packaging: Packaging the cells that have passed the test to make the battery;

[0017] Step 10: Formation: The packaged batteries are subjected to formation treatment.

[0018] Preferably, the process of mixing the positive electrode material and the electrolyte solution in step 1 is:

[0019] S1.1. Material selection: The positive electrode material is composed of lithium nickel oxide, lithium iron oxide and lithium nickel cobalt aluminum oxide in a weight ratio of 3:1:2, the materials are mixed to form a mixture, and the mixture is ground into particles between 200 nanometers and 215 nanometers by a nano sand mill;

[0020] S1.2, electrolyte selection: an electrolyte solution is formed by using diethyl carbonate and tetraethylene glycol dimethyl ether in a weight ratio of 3:4;

[0021] S1.3, additive selection: vinyl sulfate and graphene in a weight ratio of 1:1 to form an additive;

[0022] S1.4, mixing operation: in a vacuum container with a solution temperature of 45-55°C and a vacuum degree of 50-70 mbar, perform mixing for 1-3 hours while continuously stirring to form a positive electrode material slurry.

[0023] Preferably, the process of mixing the negative electrode material and the electrolyte solution in step 1 is:

[0024] S2.1. Material selection: A Sn-Co-C composite material and carbon nanotubes in a weight ratio of 3:1 are used to form a negative electrode material, the materials are mixed to form a mixture, and the mixture is ground into particles between 80 nanometers and 100 nanometers by a nano sand mill;

[0025] S2.2, electrolyte selection: an electrolyte solution is composed of dimethyl carbonate and propylene carbonate in a weight ratio of 4:1;

[0026] S2.3, additive selection: additives are composed of α-aluminum oxide, hydrolyzed polymaleic anhydride and vinylene carbonate in a weight ratio of 1:1:3;

[0027] S2.4, mixing operation: in a vacuum container with a solution temperature of 50-60°C and a vacuum degree of 50-70 mbar, perform mixing for 50-80 minutes while continuously stirring to form a negative electrode material slurry.

[0028] Preferably, the composite process of the Sn-Co-C composite material is as follows: weigh a tin source, a cobalt source and a carbon source at a molar ratio of Sn:Co:C of 1:1:3, add deionized water accounting for 1 / 10 of the composite material, use a ball mill to ball mill for 2-3 hours to obtain a composite mixture, and calcine the mixture at a constant temperature of 800-900°C for 10-12 hours in a nitrogen environment with a nitrogen content greater than 99%, and obtain a Sn-Co-C composite negative electrode material after natural cooling.

[0029] Preferably, in the coating process of step 2, the positive electrode material slurry is coated on the aluminum foil using a coating machine, with a coating thickness between 100 and 150 microns, and the negative electrode material slurry is coated on the copper foil, with a coating thickness between 80 and 100 microns.

[0030] Preferably, in the drying step 2, the electrode is dried at a temperature of 60-80° C. for 15-30 minutes.

[0031] Preferably, in the step 4, the diaphragm is prepared by selecting polyethylene as the diaphragm material, and using an electrostatic eliminator to perform electrostatic removal treatment in a clean room environment at a relative humidity of 55% to 60% and a temperature of 22°C to 25°C, and the treatment time is controlled between 10 and 15 minutes.

[0032] Preferably, in the unwinding process in step five: the unwinding speed is set between 30-35 m / min, the unwinding tension is set between 10-15 N, and the pressure fluctuation range is maintained at ±0.15 N.

[0033] Preferably, the automatic lamination process in step seven:

[0034] S3.1. After setting the unwinding parameters, at the specified position;

[0035] S3.2, unwinding, during which the position of the diaphragm is monitored and dynamically adjusted by the deviation correction intelligent control system in real time, and the correction accuracy is controlled within ±0.20mm. At the same time, the guide plate is used to guide the direction of the diaphragm.

[0036] Preferably, the chemical formation treatment in step ten is:

[0037] S4.1. Shelter after filling: After the battery is filled, it is shelved for 10-12 hours;

[0038] S4.2, first charge: charge the battery for the first time by charging and discharging with a small current to activate the positive and negative electrode materials;

[0039] S4.3, SEI film formation: During the charging process, the electrolyte solvent and lithium salt react with each other. + It escapes from the positive electrode and embeds into the graphite layer of the negative electrode, forming SEI film and gas at the negative electrode;

[0040] S4.4, Exhaust and fluid replenishment: perform exhaust and fluid replenishment operations during the formation process;

[0041] S4.5, aging treatment: the formed battery is aged by placing it in an environment of 40-50℃ for 48-50h;

[0042] S4.6, Testing and sorting: After formation, the battery is tested for internal resistance, voltage, size and weight. The battery is sorted according to the test results and unqualified batteries are eliminated.

[0043] Compared with the prior art, the present invention provides a new energy lithium battery lamination process, which has the following advantages:

[0044] Beneficial effects:

[0045] 1. The present invention improves the performance and safety of the battery by accurately controlling the diaphragm tension through multiple links such as tension setting in the unwinding process, advantageous characteristics of the lamination process, application of diaphragm tension control technology, and parameter control in the formation process through the new energy lithium battery lamination process. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 It is a process flow chart of the present invention. DETAILED DESCRIPTION

[0047] The following will be combined with the drawings in 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.

[0048] See also Figure 1 , a new energy lithium battery lamination process, comprising the following steps:

[0049] Step 1: Mixing the positive electrode material and the negative electrode material with the corresponding electrolyte solution under different conditions, and stirring them fully to form positive and negative electrode material slurries (ensuring uniform distribution of the materials);

[0050] Step 2: coating and drying: coating the stirred positive and negative electrode material slurries on the corresponding aluminum foil and copper foil to form positive and negative electrode sheets;

[0051] Step 3: Die-cutting and slitting: Die-cut and slitting the dried electrode to obtain the required size and shape;

[0052] Step 4: Diaphragm preparation: Select the diaphragm material and perform pretreatment to remove static electricity;

[0053] Step 5. Set unwinding parameters: Use active continuous unwinding technology to achieve high-speed continuous active unwinding through intelligent control (keep the system tension stable);

[0054] Step 6: Transfer: Use the linear motor module to transfer the electrode sheet and the diaphragm to the stacking position;

[0055] Step 7: Automatic lamination: Start unwinding, and alternately stack the positive electrode sheet, the separator, and the negative electrode sheet on the lamination table to form a multi-layer lamination structure;

[0056] Step 8: Pre-charge and discharge test: Perform pre-charge and discharge test on the stacked cells to detect their performance and safety;

[0057] Step 9: Packaging: Packaging the cells that have passed the test to make the battery;

[0058] Step 10: Formation: The packaged batteries are subjected to formation treatment to make them usable.

[0059] Specifically, the composite process of the Sn-Co-C composite material is as follows: weigh a tin source, a cobalt source and a carbon source at a molar ratio of Sn:Co:C of 1:1:3, add deionized water accounting for 1 / 10 of the composite material, use a ball mill to ball mill for 2-3 hours to obtain a composite mixture, and calcine the mixture at a constant temperature of 800-900°C for 10-12 hours in a nitrogen environment with a nitrogen content greater than 99%, and obtain a Sn-Co-C composite negative electrode material after natural cooling.

[0060] Specifically, in the coating process of step 2, the positive electrode material slurry is coated on the aluminum foil using a coating machine, and the coating thickness is between 100 and 150 microns, and the negative electrode material slurry is coated on the copper foil, and the coating thickness is between 80 and 100 microns.

[0061] Specifically, in step 2, drying: the electrode is dried at a temperature of 60-80° C. for 15-30 minutes.

[0062] Specifically, in step 4, the diaphragm is prepared by selecting polyethylene as the diaphragm material, and using an electrostatic eliminator to perform electrostatic removal treatment in a clean room environment at a relative humidity of 55% to 60% and a temperature of 22°C to 25°C, and the treatment time is controlled between 10 and 15 minutes.

[0063] Specifically, in the unwinding process in step 5: the unwinding speed is set between 30-35 m / min, the unwinding tension is set between 10-15 N, and the pressure fluctuation range is maintained at ±0.15 N.

[0064] Specifically, the automatic lamination process in step seven:

[0065] S3.1. After setting the unwinding parameters, at the specified position;

[0066] S3.2, unwinding, during which the position of the diaphragm is monitored and dynamically adjusted by the intelligent deviation correction control system in real time, and the correction accuracy is controlled within ±0.20mm (to maintain its alignment with the stacking table. The performance of the deviation correction system directly affects the stability of the diaphragm tension). At the same time, a guide plate is used to guide the direction of the diaphragm.

[0067] Specifically, the chemical treatment in step 10:

[0068] S4.1. Standby after injection: After the battery is filled, standby for 10-12 hours (to allow the electrolyte to fully infiltrate the electrode material);

[0069] S4.2, first charge: charge the battery for the first time by charging and discharging with a small current to activate the positive and negative electrode materials;

[0070] S4.3, SEI film formation: During the charging process, the electrolyte solvent and lithium salt react with each other. + It escapes from the positive electrode and embeds into the graphite layer of the negative electrode, forming a SEI film and gas at the negative electrode (this film can prevent further side reactions and reduce the loss of active lithium);

[0071] Formation data and time growth of SEI film generation Table 1

[0072]

[0073]

[0074] Data table 2 of gas release and time increase

[0075]

[0076] S4.4, exhaust and refilling: exhaust and refilling operations are performed during the formation process (to ensure the quality of the SEI film and battery performance). Through vacuuming, standing, pre-charging, secondary refilling and other steps, the electrolyte fully infiltrates the pores of the electrode, which is conducive to the formation of a uniform and stable SEI film;

[0077] Table 3 Data of exhaust and fluid replenishment and time

[0078]

[0079]

[0080] S4.5, aging treatment: the formed battery is aged by placing it in an environment of 40-50°C for 48-50 hours (to make the SEI film more stable and improve the electrochemical performance of the battery). This process helps to make the SEI film more stable and improve the electrochemical performance of the battery.

[0081] S4.6, Testing and sorting: After formation, the battery is tested for internal resistance, voltage, size and weight. The battery is sorted according to the test results and unqualified batteries are eliminated.

[0082] Example 1

[0083] The mixing process of the positive electrode material and the electrolyte solution is:

[0084] S1.1. Material selection: The positive electrode material is composed of lithium nickel oxide, lithium iron oxide and lithium nickel cobalt aluminum oxide in a weight ratio of 3:1:2, the materials are mixed to form a mixture, and the mixture is ground into particles of 200 nanometers by a nano sand mill;

[0085] S1.2, electrolyte selection: an electrolyte solution is formed by using diethyl carbonate and tetraethylene glycol dimethyl ether in a weight ratio of 3:4;

[0086] S1.3, additive selection: vinyl sulfate and graphene in a weight ratio of 1:1 to form an additive;

[0087] S1.4, mixing operation: in a vacuum container at a solution temperature of 45°C and a vacuum degree of 60 mbar, mixing is performed for 2.5 hours while continuously stirring to form a positive electrode material slurry.

[0088] Example 2

[0089] The mixing process of negative electrode material and electrolyte solution is:

[0090] S2.1. Material selection: A Sn-Co-C composite material and carbon nanotubes in a weight ratio of 3:1 are used to form a negative electrode material, the materials are mixed to form a mixture, and the mixture is ground into particles of 85 nanometers by a nano sand mill;

[0091] S2.2, electrolyte selection: an electrolyte solution is composed of dimethyl carbonate and propylene carbonate in a weight ratio of 4:1;

[0092] S2.3, additive selection: additives are composed of α-aluminum oxide, hydrolyzed polymaleic anhydride and vinylene carbonate in a weight ratio of 1:1:3;

[0093] S2.4, mixing operation: in a vacuum container with a solution temperature of 50° C. and a vacuum degree of 50 mbar, mixing is performed for 55 minutes while continuously stirring to form a negative electrode material slurry.

[0094] Example 3

[0095] Unwinding process using lamination technology: unwinding speed is set at 30m / min, unwinding tension is set at 15N, and pressure fluctuation range is maintained at ±0.15N.

[0096] Comparative Example 1

[0097] The mixing process of the positive electrode material and the electrolyte solution is:

[0098] S1.1. Material selection: lithium nickel oxide and lithium iron oxide in a weight ratio of 4:3 are used to form a positive electrode material, the materials are mixed to form a mixture, and the mixture is ground into particles of 300 nanometers by a nano sand mill;

[0099] S1.2, Electrolyte selection: diethyl carbonate is used as the electrolyte solution;

[0100] S1.3, Additive selection: vinyl sulfate is used as additive;

[0101] S1.4, mixing operation: in a vacuum container at a solution temperature of 45°C and a vacuum degree of 60 mbar, mixing is performed for 2.5 hours while continuously stirring to form a positive electrode material slurry.

[0102] Comparative Example 2

[0103] The mixing process of negative electrode material and electrolyte solution is:

[0104] S2.1. Material selection: Using carbon nanotubes as negative electrode materials, the materials are mixed to form a mixture, and the mixture is ground into particles of 150 nanometers by a nano sand mill;

[0105] S2.2, electrolyte selection: an electrolyte solution is composed of dimethyl carbonate and propylene carbonate in a weight ratio of 4:1;

[0106] S2.3, additive selection: the additive is composed of hydrolyzed polymaleic anhydride and vinylene carbonate in a weight ratio of 1:3;

[0107] S2.4, mixing operation: in a vacuum container with a solution temperature of 70° C. and a vacuum degree of 40 mbar, mixing is performed for 90 minutes to form a negative electrode material slurry.

[0108] Comparative Example 3

[0109] The unwinding process uses a winding process: the unwinding speed is set at 45m / min, the unwinding tension is set at 9N, and the pressure fluctuation range is maintained at ±0.15N.

[0110] According to the batteries made in the above embodiments and comparative examples, internal resistance, voltage, size and weight of the batteries were tested, and the batteries were sorted according to the test results to remove unqualified batteries. The test data are shown in Table 4 below:

[0111] Table 4

[0112]

[0113] From Table 4 above, we can see that:

[0114] Tension control during the unwinding process: The unwinding speed mentioned in Example 3 is set at 30m / min, the unwinding tension is set at 15N, and the pressure fluctuation range is maintained at ±0.15N. This precise tension control helps to maintain the uniformity of the diaphragm during the battery stacking process, thereby improving the overall performance and safety of the battery.

[0115] Advantages of the lamination process: Compared with the traditional winding process of Comparative Example 3, the lamination process of Example 3 has the advantages of high volume utilization, structural stability, small internal resistance and long cycle life, which helps to increase the high energy density of the battery and extend the battery life.

[0116] In summary, the new energy lithium battery lamination process in the embodiment improves the performance and safety of the battery by accurately controlling the diaphragm tension in multiple links including tension setting in the unwinding process, advantageous characteristics of the lamination process, application of diaphragm tension control technology, and parameter control in the formation process.

[0117] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A new energy lithium battery lamination process, characterized in that: The following steps are involved: Step 1: Mixing the positive electrode material and the negative electrode material with the corresponding electrolyte solution under different conditions, and stirring them fully to form positive and negative electrode material slurries; Step 2: coating and drying: coating the stirred positive and negative electrode material slurries on the corresponding aluminum foil and copper foil to form positive and negative electrode sheets; Step 3: Die-cutting and slitting: Die-cut and slitting the dried electrode to obtain the required size and shape; Step 4: Diaphragm preparation: Select the diaphragm material and perform pretreatment to remove static electricity; Step 5. Set unwinding parameters: Use active continuous unwinding technology to achieve high-speed continuous active unwinding through intelligent control; Step 6: Transfer: Use the linear motor module to transfer the electrode sheet and the diaphragm to the stacking position; Step 7: Automatic lamination: Start unwinding, and alternately stack the positive electrode sheet, the separator, and the negative electrode sheet on the lamination table to form a multi-layer lamination structure; Step 8: Pre-charge and discharge test: Perform pre-charge and discharge test on the stacked cells to detect their performance and safety; Step 9: Packaging: Packaging the cells that have passed the test to make the battery; Step 10: Formation: The packaged batteries are subjected to formation treatment.

2. A new energy lithium battery lamination process according to claim 1, characterized in that: The process of mixing the positive electrode material and the electrolyte solution in step 1 is as follows: S1.

1. Material selection: The positive electrode material is composed of lithium nickel oxide, lithium iron oxide and lithium nickel cobalt aluminum oxide in a weight ratio of 3:1:2, the materials are mixed to form a mixture, and the mixture is ground into particles between 200 nanometers and 215 nanometers by a nano sand mill; S1.2, electrolyte selection: an electrolyte solution is formed by using diethyl carbonate and tetraethylene glycol dimethyl ether in a weight ratio of 3:4; S1.3, additive selection: vinyl sulfate and graphene in a weight ratio of 1:1 to form an additive; S1.4, mixing operation: in a vacuum container with a solution temperature of 45-55°C and a vacuum degree of 50-70 mbar, perform mixing for 1-3 hours while continuously stirring to form a positive electrode material slurry.

3. A new energy lithium battery lamination process according to claim 1, characterized in that: The process of mixing the negative electrode material and the electrolyte solution in step 1 is as follows: S2.

1. Material selection: A Sn-Co-C composite material and carbon nanotubes in a weight ratio of 3:1 are used to form a negative electrode material, the materials are mixed to form a mixture, and the mixture is ground into particles between 80 nanometers and 100 nanometers by a nano sand mill; S2.2, electrolyte selection: an electrolyte solution is composed of dimethyl carbonate and propylene carbonate in a weight ratio of 4:1; S2.3, additive selection: additives are composed of α-aluminum oxide, hydrolyzed polymaleic anhydride and vinylene carbonate in a weight ratio of 1:1:3; S2.4, mixing operation: in a vacuum container with a solution temperature of 50-60°C and a vacuum degree of 50-70 mbar, perform mixing for 50-80 minutes while continuously stirring to form a negative electrode material slurry.

4. The new energy lithium battery lamination process according to claim 1, characterized in that: The composite process of the Sn-Co-C composite material is as follows: weigh a tin source, a cobalt source and a carbon source at a molar ratio of Sn:Co:C of 1:1:3, add deionized water accounting for 1 / 10 of the composite material, use a ball mill to ball mill for 2-3 hours to obtain a composite mixture, and calcine the mixture at a constant temperature of 800-900°C for 10-12 hours in a nitrogen environment with a nitrogen content greater than 99%, and obtain a Sn-Co-C composite negative electrode material after natural cooling.

5. The new energy lithium battery lamination process according to claim 1, characterized in that: The coating process in step 2 is as follows: using a coating machine to coat the positive electrode material slurry on the aluminum foil with a coating thickness of 100 to 150 microns, and coating the negative electrode material slurry on the copper foil with a coating thickness of 80 to 100 microns.

6. The new energy lithium battery lamination process according to claim 1, characterized in that: Drying in the step 2: drying the electrode at a temperature of 60-80° C. for 15-30 minutes.

7. The new energy lithium battery lamination process according to claim 1, characterized in that: The diaphragm preparation in step 4 is as follows: polyethylene is selected as the diaphragm material, and an antistatic eliminator is used to perform antistatic treatment in a clean room environment at a relative humidity of 55% to 60% and a temperature of 22° C. to 25° C., and the treatment time is controlled between 10 and 15 minutes.

8. The new energy lithium battery lamination process according to claim 1, characterized in that: In the unwinding process in step 5, the unwinding speed is set between 30-35 m / min, the unwinding tension is set between 10-15 N, and the pressure fluctuation range is maintained at ±0.15 N.

9. The new energy lithium battery lamination process according to claim 1, characterized in that: The automatic lamination process in step seven: S3.

1. After setting the unwinding parameters, at the specified position; S3.2, unwinding, during which the position of the diaphragm is monitored and dynamically adjusted by the deviation correction intelligent control system in real time, and the correction accuracy is controlled within ±0.20mm. At the same time, the guide plate is used to guide the direction of the diaphragm.

10. The new energy lithium battery lamination process according to claim 1, characterized in that: The chemical treatment in step 10: S4.

1. Shelter after filling: After the battery is filled, it is shelved for 10-12 hours; S4.2, first charge: charge the battery for the first time by charging and discharging with a small current to activate the positive and negative electrode materials; S4.3, SEI film formation: During the charging process, the electrolyte solvent and lithium salt react with each other. + It escapes from the positive electrode and embeds into the graphite layer of the negative electrode, forming SEI film and gas at the negative electrode; S4.4, Exhaust and fluid replenishment: perform exhaust and fluid replenishment operations during the formation process; S4.5, aging treatment: the formed battery is aged by placing it in an environment of 40-50℃ for 48-50h; S4.6, Testing and sorting: After formation, the battery is tested for internal resistance, voltage, size and weight. The battery is sorted according to the test results and unqualified batteries are eliminated.

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