New energy lithium battery lamination process

Abstract

The application relates to the technical field of battery manufacturing, and discloses a new energy lithium battery lamination process. Positive electrode material and negative electrode material are respectively mixed with corresponding electrolyte solutions under different conditions, and are fully stirred to form positive electrode material slurry and negative electrode material slurry. The stirred positive electrode material slurry and negative electrode material slurry are respectively coated on corresponding aluminum foils and copper foils to form positive electrode sheets and negative electrode sheets. The dried electrode sheets are die-cut and slitted to obtain required sizes and shapes. A diaphragm material is selected, and a pretreatment work of removing static electricity is carried out. An active continuous unwinding technology is adopted, high-speed continuous active unwinding is realized through intelligent control, a linear motor module is used to move the electrode sheets and the diaphragm to a lamination position, unwinding is started, positive electrode sheets, diaphragms and negative electrode sheets are alternately stacked on a lamination table to form a multilayer lamination structure, a completed battery cell is subjected to pre-charge and discharge test to detect the performance and safety of the battery cell, the battery cell that passes the test is packaged, and a battery is manufactured.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of battery manufacturing, in particular to a new energy lithium battery lamination process. BACKGROUND

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

[0003] In the lamination process, the tension control of the separator is crucial. When the tension is too large, the separator is prone to deformation or even tearing, resulting in frequent interruptions in the production process and reducing production efficiency. When the tension is too small, the separator is prone to wrinkle and shrinkage, causing the separator to be stacked off-center during lamination, which in turn affects the overall performance and safety of the battery. Therefore, precise control of the tension of the separator is one of the key factors to ensure the quality of the battery. SUMMARY

[0004] (I) Technical problems solved

[0005] In view of the shortcomings of the prior art, the present application provides a new energy lithium battery lamination process, which has the advantage of being able to accurately control the tension of the separator, and solves the problem of being unable to accurately control the tension of the separator in the prior art.

[0006] (II) Technical solutions

[0007] To achieve the above-mentioned purpose, the present application provides the following technical solutions: a new energy lithium battery lamination process, comprising the following steps:

[0008] Step 1, batching: mix the positive and negative materials with the corresponding electrolyte solution under different conditions, and stir thoroughly to form positive and negative material slurries;

[0009] Step 2, coating and drying: coat the stirred positive and negative 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 slit the dried electrode sheets to obtain the desired size and shape;

[0011] Step 4, separator preparation: select a separator material and perform a pre-treatment work to remove static electricity;

[0012] Step 5, set the unwinding parameters: use active continuous unwinding technology to achieve high-speed continuous active unwinding through intelligent control;

[0013] Step 6, transfer: use a linear motor module to transfer the electrode sheets and the separator to the lamination position;

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

[0015] Step eight, pre-charge and discharge test: the completed cell is tested for performance and safety;

[0016] Step nine, packaging: the qualified cell is packaged, and the battery is made;

[0017] Step ten, formation: the packaged battery is subjected to formation treatment.

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

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

[0020] S1.2, electrolyte selection: diethyl carbonate and tetraethylene glycol dimethyl ether are mixed in a weight ratio of 3:4 to form an electrolyte solution;

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

[0022] S1.4, mixing operation: the mixing is carried out in a vacuum container with a solution temperature of 45-55℃ and a vacuum degree of 50-70 millibars for 1-3 hours, while continuously stirring, to form a positive electrode material slurry.

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

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

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

[0026] S2.3, additive selection: alpha-aluminum oxide, hydrolyzed polymaleic anhydride and vinylene carbonate are mixed in a weight ratio of 1:1:3 to form an additive;

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

[0028] Preferably, the Sn-Co-C composite material is prepared by the following process: tin source, cobalt source and carbon source are weighed according to a molar ratio of Sn:Co:C of 1:1:3, deionized water is added at a proportion of 1 / 10 of the composite material, ball milling is performed for 2-3 h using a ball mill, a composite mixture is obtained, the mixture is calcined at a temperature of 800-900 DEG C for 10-12 h in a nitrogen environment with a content of more than 99%, and the Sn-Co-C composite negative electrode material is obtained after natural cooling.

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

[0030] Preferably, the drying in step two is as follows: the electrode piece is dried at a temperature of 60-80 DEG C for 15-30 min.

[0031] Preferably, the separator preparation in step four is as follows: polyethylene is selected as the separator material, and the electrostatic elimination treatment is performed in a dust-free room environment using an electrostatic eliminator, the relative humidity is 55%-60%, the temperature is 22 DEG C-25 DEG C, and the treatment time is controlled to be between 10 and 15 min.

[0032] Preferably, the unwinding process in step five is as follows: the unwinding speed is set to be between 30 and 35 m / min, the unwinding tension is set to be between 10 and 15 N, and the pressure fluctuation range is kept within ±0.15 N.

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

[0034] S3.1, after the unwinding parameters are set, the separator is guided to a specified position;

[0035] S3.2, unwinding is performed, and the position of the separator is monitored and dynamically adjusted in real time by the deviation correction intelligent control system during the unwinding process, the correction accuracy is controlled to be within ±0.20 mm, and a guide plate is used to guide the running direction of the separator.

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

[0037] S4.1, after the liquid injection process, the battery is left to stand for 10-12 h;

[0038] S4.2 First charge: The battery is charged for the first time using a small current charging and discharging method to activate the positive and negative electrode materials;

[0039] S4.3, SEI film formation: During charging, a side reaction occurs between the electrolyte solvent and the lithium salt, Li... + It is extracted from the positive electrode and embedded between the graphite layers of the negative electrode to form an SEI film and gas at the negative electrode;

[0040] S4.4, Degassing and Liquid Replenishment: Degassing and liquid replenishment are performed during the formation process;

[0041] S4.5 Aging treatment: The formed battery is subjected to aging treatment by placing it in an environment of 40-50℃ for 48-50 hours.

[0042] S4.6 Inspection and sorting: After formation, the batteries are inspected for internal resistance, voltage, size and weight. Based on the test results, the batteries are sorted and unqualified products are removed.

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

[0044] Beneficial effects:

[0045] 1. This invention improves battery performance and safety by precisely controlling the separator tension in multiple stages, including tension setting during the unwinding process, the advantages of the stacking process, the application of separator tension control technology, and parameter control in the formation process, through the new energy lithium battery stacking process. Attached Figure Description

[0046] Figure 1 This is a process flow diagram of the present invention. Detailed Implementation

[0047] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0048] Please see Figure 1 A new energy lithium battery stacking process includes the following steps:

[0049] Step 1, Ingredient Preparation: Mix the positive electrode material and the negative electrode material with the corresponding electrolyte solution under different conditions and stir thoroughly to form positive and negative electrode material slurries (ensuring uniform distribution of materials);

[0050] Step two, coating and drying: the stirred positive and negative electrode material slurry is coated on the corresponding aluminum foil and copper foil respectively to form positive and negative electrode sheets;

[0051] Step three, die cutting and striping: the dried electrode sheet is die cut and striping to obtain the required size and shape;

[0052] Step four, separator preparation: select the separator material and perform the pre-treatment work of removing static electricity;

[0053] Step five, set the unwinding parameters: use active continuous unwinding technology to achieve high-speed continuous active unwinding (keep the system tension stable) through intelligent control;

[0054] Step six, transfer: use a linear motor module to transfer the electrode sheet and the separator to the lamination position;

[0055] Step seven, 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 eight, pre-charge and discharge test: perform a pre-charge and discharge test on the completed cell to detect its performance and safety;

[0057] Step nine, packaging: package the tested qualified cell to make a battery;

[0058] Step ten, formation: perform formation treatment on the packaged battery to make it reach a usable state.

[0059] Specifically, the composite process of the Sn-Co-C composite material is as follows: tin source, cobalt source and carbon source are weighed in a molar ratio of 1:1:3, deionized water accounting for 1 / 10 of the proportion of the composite material is added, a ball mill is used for ball milling for 2-3h to obtain a composite mixture, the mixture is calcined at a temperature of 800-900℃ for 10-12h in a nitrogen environment with a content of more than 99%, and then naturally cooled to obtain the Sn-Co-C composite negative electrode material.

[0060] Specifically, the coating process in step two: 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; the negative electrode material slurry is coated on the copper foil, and the coating thickness is between 80 and 100 microns.

[0061] Specifically, the drying in step two: the electrode sheet is dried at a temperature of 60-80℃ for 15-30min.

[0062] Specifically, the diaphragm preparation in step four: polyethylene is selected as the diaphragm material, and the static electricity eliminator is used to remove static electricity in a dust-free room environment with a relative humidity of 55% to 60% and a temperature of 22°C to 25°C, and the treatment time is controlled between 10 to 15 minutes.

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

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

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

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

[0067] Specifically, the formation treatment in step ten:

[0068] S4.1, after injection, stand by: after the battery completes the injection process, stand by for 10-12h (so that the electrolyte can fully soak the electrode material);

[0069] S4.2, first charge: the battery is first charged by small current charge and discharge to activate the positive and negative electrode materials;

[0070] S4.3, SEI film formation: during the charging process, the electrolyte solvent and lithium salt undergo side reactions, Li + is released from the positive electrode and inserted into the interlayer of the negative electrode graphite, forming an SEI film and gas at the negative electrode (this film can prevent further side reactions and reduce the loss of active lithium);

[0071] SEI film formation data and time increase table 1

[0072]

[0073]

[0074] Gas release and time increase data table 2

[0075]

[0076] S4.4, Exhaust and liquid supplement: exhaust and liquid supplement operation is carried out during the formation process (to ensure the quality of SEI film and battery performance), exhaust and liquid supplement operation is carried out during the formation process to ensure the quality of SEI film and battery performance. Through the steps of vacuumizing, standing, pre-charging, secondary liquid supplement, etc., the electrolyte is fully infiltrated into the pores of the pole piece, which is beneficial to form uniform and stable SEI film;

[0077] Exhaust and liquid supplement and time data table 3

[0078]

[0079]

[0080] S4.5, aging treatment: the battery after formation is placed in the environment of 40-50℃, and the aging time is 48-50h (to make the SEI film more stable and improve the electrochemical performance of the battery), which helps to make the SEI film more stable and improve the electrochemical performance of the battery;

[0081] S4.6, detection and sorting: after the formation is completed, the battery is detected in terms of internal resistance, voltage, size and weight, and the battery is sorted according to the test results, and the unqualified products are removed.

[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 the proportion of 3:1:2 by weight, the mixture is formed after mixing the materials, and the mixture is ground to 200 nanometer particles by nano sand mill;

[0085] S1.2, electrolyte selection: the electrolyte solution is composed of diethyl carbonate and tetraethylene glycol dimethyl ether in the proportion of 3:4 by weight;

[0086] S1.3, additive selection: the additive is composed of vinyl sulfate and graphene in the proportion of 1:1 by weight;

[0087] S1.4, mixing operation: the mixing is carried out in a vacuum container with the solution temperature of 45℃ and the vacuum degree of 60 millibars for 2.5h, and the stirring is continuously carried out to form the positive electrode material slurry.

[0088] Example 2

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

[0090] S2.1, material selection: Sn-Co-C composite material and carbon nanotubes in a weight ratio of 3:1 to form a negative electrode material, mix the materials to form a mixture, and grind the mixture to 85 nanometers of particles by a nano sand mill;

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

[0092] S2.3, additive selection: alpha-aluminum oxide, hydrolyzed polymaleic anhydride, and vinylene carbonate in a weight ratio of 1:1:3 to form an additive;

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

[0094] Example 3

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

[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 to form a positive electrode material, mix the materials to form a mixture, and grind the mixture to 300 nanometers of particles by a nano sand mill;

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

[0100] S1.3, additive selection: vinyl sulfate as an additive;

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

[0102] Comparative Example 2

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

[0104] S2.1, material selection: carbon nanotubes as a negative electrode material, mix the materials to form a mixture, and grind the mixture to 150 nanometers of particles by a nano sand mill;

[0105] S2.2, electrolyte selection: the 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: mixing is carried out in a vacuum container with a solution temperature of 70°C and a vacuum degree maintained between 40 mbar for a duration of 90 min, forming a negative electrode material slurry.

[0108] Comparative Example 3

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

[0110] According to the batteries made according to the above examples and comparative examples, the batteries are tested for internal resistance, voltage, size and weight, and according to the test results, the batteries are sorted, and unqualified products are rejected, and the test data are as follows Table 4:

[0111] Table 4

[0112]

[0113] From the above Table 4, it can be seen that:

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

[0115] Advantages of the lamination process: the lamination process of Example 3 has the advantages of high volume utilization, structural stability, small internal resistance and long cycle life compared to the traditional winding process of Comparative Example 3. These advantages help to increase the energy density of the battery and prolong the life of the battery.

[0116] In summary, the new energy lithium battery lamination process in the example precisely controls the separator tension through the tension setting during the unwinding process, the advantages of the lamination process, the application of the separator tension control technology and the parameter control in the formation process, thereby improving the performance and safety of the battery.

[0117] Although embodiments of the present application have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made therein without departing from the principles and spirit of the application, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A new energy lithium battery stacking process, characterized in that, Includes the following steps: Step 1, Ingredient Preparation: Mix the positive electrode material and the negative electrode material with the corresponding electrolyte solution under different conditions and stir thoroughly to form positive and negative electrode material slurries; Step 2, Coating and Drying: Coat the well-stirred positive and negative electrode material slurries onto the corresponding aluminum foil and copper foil respectively to form positive and negative electrode sheets; Step 3: Die-cutting and slitting: The dried electrode sheets are die-cut and slitting to obtain the required size and shape; Step 4: Diaphragm preparation: Select diaphragm material and perform static electricity removal pretreatment; Step 5: Set unwinding parameters: Adopt active continuous unwinding technology, and realize high-speed continuous active unwinding through intelligent control; Step 6, Transfer: Use a linear motor module to transfer the electrode sheet and diaphragm to the stacking position; Step 7, Automatic Stacking: Begin unwinding and alternately stack the positive electrode, separator, and negative electrode on the stacking table to form a multi-layer stacked structure; Step 8: Pre-charge and discharge test: Perform a pre-charge and discharge test on the stacked cells to check their performance and safety; Step 9, Packaging: The tested and qualified battery cells are packaged to complete the battery production; Step 10, Formation: The packaged battery undergoes formation treatment; In step four, the diaphragm is prepared by selecting polyethylene as the diaphragm material and using an electrostatic eliminator in a cleanroom environment with a relative humidity of 55% to 60% and a temperature of 22°C to 25°C for static elimination treatment, with the treatment time controlled between 10 and 15 minutes. In step five, the unwinding process is as follows: 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 within ±0.15 N. The automatic stacking process in step seven: S3.1 After setting the unwinding parameters, place it in the designated position; S3.

2. Unwinding: During the unwinding process, the position of the diaphragm is monitored and dynamically adjusted in real time by the intelligent correction control system to control the correction accuracy within ±0.20mm. At the same time, the guide plate is used to guide the direction of the diaphragm. The formation process in step ten: S4.1 Post-liquid injection rest: After the liquid injection process is completed, the battery should be rested for 10-12 hours. S4.2 First charge: The battery is charged for the first time using a small current charging and discharging method to activate the positive and negative electrode materials; S4.3, SEI film formation: During charging, a side reaction occurs between the electrolyte solvent and the lithium salt, Li... + It is extracted from the positive electrode and embedded between the graphite layers of the negative electrode to form an SEI film and gas at the negative electrode; S4.4, Degassing and Liquid Replenishment: Degassing and liquid replenishment are performed during the formation process; S4.5 Aging treatment: The formed battery is subjected to aging treatment by placing it in an environment of 40-50℃ for 48-50 hours. S4.6 Inspection and sorting: After formation, the batteries are inspected for internal resistance, voltage, size and weight. Based on the test results, the batteries are sorted and unqualified products are removed.

2. The new energy lithium battery stacking process according to claim 1, characterized in that: The mixing process of the positive electrode material and the electrolyte solution in step one is as follows: S1.1 Material selection: The cathode 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: The electrolyte solution is composed of diethyl carbonate and tetraethylene glycol dimethyl ether in a weight ratio of 3:

4. S1.3, Additive selection: The additive is composed of vinyl sulfate and graphene in a weight ratio of 1:1; S1.4 Mixing operation: Mix for 1-3 hours in a vacuum container with a solution temperature of 45-55℃ and a vacuum degree maintained between 50-70 mbar, while stirring continuously, to form a positive electrode material slurry.

3. The new energy lithium battery stacking process according to claim 1, characterized in that: The mixing process of the negative electrode material and the electrolyte solution in step one is as follows: S2.1 Material selection: Sn-Co-C composite material with a weight ratio of 3:1 and carbon nanotubes are used to form the negative electrode material. The materials are mixed to form a mixture, and the mixture is ground into particles between 80 nanometers and 100 nanometers using a nano-sand mill. S2.2 Electrolyte selection: The electrolyte solution is composed of dimethyl carbonate and propylene carbonate in a weight ratio of 4:1; S2.3, Additive selection: The additives consist of α-alumina, hydrolyzed polymaleic anhydride and vinylene carbonate in a weight ratio of 1:1:

3. S2.4 Mixing operation: Mix for 50-80 minutes in a vacuum container with a solution temperature of 50-60℃ and a vacuum degree maintained between 50-70 mbar, while stirring continuously, to form a negative electrode material slurry.

4. The new energy lithium battery stacking process according to claim 3, characterized in that: The composite process of the Sn-Co-C composite material is as follows: tin source, cobalt source and carbon source are weighed with a Sn:Co:C molar ratio of 1:1:3, and deionized water accounting for 1 / 10 of the composite material is added. The mixture is ball-milled for 2-3 hours to obtain a composite mixture. The mixture is then calcined at 800-900℃ for 10-12 hours in a nitrogen atmosphere with a nitrogen content greater than 99%. After natural cooling, the Sn-Co-C composite anode material is obtained.

5. The new energy lithium battery stacking process according to claim 1, characterized in that: In step two, the coating process involves using a coating machine to coat the positive electrode material slurry onto an aluminum foil with a coating thickness between 100 and 150 micrometers, and then coating the negative electrode material slurry onto a copper foil with a coating thickness between 80 and 100 micrometers.

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

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