Production process method of cylindrical lithium ion battery and cylindrical lithium ion battery

Abstract

The invention discloses a production process method of a cylindrical lithium ion battery. The production process method comprises the following steps: a cap preparation process: a positive pole aluminum plate, a positive pole ring, an insulating layer, a protective circuit board PCBA and a negative pole ring are sequentially placed in a sealing ring, the protective circuit board PCBA is welded with the positive pole ring, the positive pole ring is in contact with the positive pole aluminum plate, and the protective circuit board PCBA is welded with the negative pole ring; the current interruption device is welded with the anode aluminum plate; the battery preparation process comprises the following steps: burdening; coating is conducted; rolling is conducted; slitting is conducted; preparing tablets; winding is conducted; the battery roll core is installed in the steel shell, a negative electrode lug of the battery roll core is welded to the bottom of the inner side of the steel shell, groove rolling is conducted on the steel shell, and a positive electrode lug of the battery roll core is welded to a current interruption device; baking the battery cell; injecting an electrolyte into the baked battery cell; the cap and the steel shell are subjected to primary sealing, secondary sealing and tertiary sealing treatment; carrying out cleaning and anti-rust treatment on the battery cell; a plastic outer film is additionally sleeved outside the battery cell; activating the battery cell; performing formation treatment on the battery cell; and carrying out capacity grading treatment on the battery cell.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of cylindrical lithium battery, in particular to a production process method of cylindrical lithium ion battery and the cylindrical lithium ion battery. BACKGROUND

[0002] Lithium ion battery is a kind of storage device, mainly using lithium metal or lithium alloy metal as negative material, charging and discharging through chemical reaction, and cylindrical lithium ion battery is a kind of battery similar to common dry battery, lithium battery is a non-disposable battery, which can be repeatedly charged and discharged. Among them, cylindrical lithium ion battery is widely used in mobile electronic devices such as household appliances, toys and cameras, and has the advantages of high energy density, easy forming and the like.

[0003] In the existing production process of cylindrical lithium ion battery, PACK process is separated from cell manufacturing, and circuit board (BMS / PCB) installation, welding and testing are separately carried out, which leads to long process chain, and 3-5% yield loss is caused by transportation and repeated positioning between processes. At the same time, the setting of circuit board outside the cell leads to the increase of battery pack thickness, which limits the internal space layout of the equipment. In addition, the cell and PACK process belong to different standard systems, and the customized development cycle is long. SUMMARY

[0004] Based on the above status, the main purpose of the present application is to provide a production process method of cylindrical lithium ion battery, which solves a series of problems caused by the separation of PACK process and cell manufacturing in the prior art, and can provide protection for battery charging and discharging and improve the safety performance of the battery.

[0005] To achieve the above purpose, the technical scheme adopted by the present application is as follows: A production process method of cylindrical lithium ion battery, comprising: Cap preparation process: Step one, sequentially put the positive aluminum plate, positive ring, insulating layer, protection circuit board PCBA and negative ring into the sealing ring, the protection circuit board PCBA is used for controlling overcharge prevention when the battery is charged and controlling overdischarge prevention when the battery is discharged, the protection circuit board PCBA is welded with the positive ring, the positive ring is in contact with the positive aluminum plate, and the protection circuit board PCBA is welded with the negative ring; Step two, weld the current interrupting device with the positive aluminum plate, and complete the cap preparation; Battery preparation process: Step one, positive and negative electrode batching; Step two, positive and negative electrode coating; Step three, positive and negative electrode rolling; Step four, positive and negative electrode slitting; Step five, positive and negative electrode sheet making; Step 6: Wind the positive and negative electrodes to form a battery core; Step 7: Place the battery core into a steel case, weld the negative electrode tab of the battery core to the inner bottom of the steel case, groove the steel case, and weld the positive electrode tab of the battery core to the current interruption device in the cap to obtain a battery cell connected to the cap. Step 8: baking the battery cell in a high vacuum oven; Step nine, injecting electrolyte into the baked battery cell; Step 10: The cap and the steel shell are put through a sealing machine for one, two, or three sealing processes; Step 11: Clean and prevent rust of the battery cell by soaking it in alkaline water and anti-rust oil; Step 12: Covering the battery core with a plastic outer film; Step 13: activating the battery cell with a small current to charge the battery cell to a first voltage, wherein the small current is 20 to 100 mA; Step 14: performing a formation treatment on the battery cell for a preset time, wherein the preset time is less than or equal to 3 hours; Step 15: performing capacity separation processing on the battery cells to obtain lithium-ion cylindrical batteries of different capacities.

[0006] Preferably, the positive electrode ring in step 1 of the cap preparation process is used as a positive temperature coefficient thermistor. When the charging current is greater than a preset value, the positive temperature coefficient thermistor controls the charging to stop; When the discharge current is greater than the preset value, the positive temperature coefficient thermistor controls the discharge to stop.

[0007] Preferably, in step 2 of the battery preparation process, The surface temperature of the positive electrode coated electrode is 125-145℃. The appearance of the positive electrode after coating is required to be free of missing materials and particles, with a gap error of ±1mm, a tailing error of less than 2mm, a total electrode error of ±1mm, and a thickness measurement within 5mm from both sides. The horizontal and vertical single-sided electrode thickness error is ±2um, and the horizontal and vertical double-sided electrode thickness error is ±3um. The surface temperature of the negative electrode coated electrode is 90-110℃. The appearance of the negative electrode after coating is required to be free of missing materials and particles, the gap error is ±1mm, the tailing error is less than 2mm, the total error of the electrode is ±1mm, the thickness of the electrode is measured within 5mm from both sides, the horizontal and vertical single-sided electrode thickness error is ±2um, the horizontal and vertical double-sided electrode thickness error is ±3um.

[0008] Preferably, the battery preparation process step five of positive and negative electrode preparation includes: Welding the tab and pasting the adhesive on the positive and negative electrode strip roll material obtained in step four, the tab is aluminum strip or nickel-plated steel strip, and the adhesive includes pasting the electrode piece adhesive and pasting the tab adhesive.

[0009] Preferably, the battery preparation process step six positive and negative electrode winding includes: Winding the separator, electrode piece adhesive and positive and negative electrode obtained in step five to form the battery roll core, the relative humidity of the winding environment is less than or equal to 30% RH, and the temperature is 20-30℃.

[0010] Preferably, the battery preparation process step fourteen includes: Trickle charging the battery cell with a first preset range of current values for one hour; Trickle charging the battery cell with a second preset range of current values for one hour; Finally, trickle charging the battery cell with a third preset range of current values for one hour; Checking whether the voltage of the cylindrical lithium ion battery is the second voltage, if so, judging that the cylindrical lithium ion battery meets the requirements, and screening out the cylindrical lithium ion battery.

[0011] Preferably, the battery preparation process step fifteen includes: Charging the battery cell to a fourth voltage with a fourth preset range of current values, and standing for a preset time; Discharging the battery cell to a fifth voltage with the fourth preset range of current values, and the cutoff current is a first current value; Finally, charging the battery cell back to the fourth voltage with the fourth preset range of current values, thereby distinguishing the capacity of the cylindrical lithium ion battery.

[0012] Preferably, the positive aluminum plate is arranged at the bottom of the inner side of the sealing ring; The positive ring is arranged in the sealing ring; The insulating layer is arranged on the inner side of the positive ring and adjacent to the positive aluminum plate; The protection circuit board PCBA is arranged above the insulating layer; The negative ring is arranged on the outer edge of the upper end of the protection circuit board PCBA; The current interrupting device is arranged on the outer side of the positive aluminum plate, and the outer side is the side of the positive aluminum plate facing the battery roll core.

[0013] Preferably, the protection circuit board PCBA has an input face and an output face, the input face is the face connected to the positive electrode signal of the positive tab of the battery roll core, and the output face is the face of the protection circuit board PCBA having the positive output of the cylindrical lithium ion battery; The protection circuit board PCBA is arranged inside the positive electrode ring, and an input surface of the protection circuit board PCBA faces the insulating layer, and the negative electrode ring is welded to an output surface of the protection circuit board PCBA.

[0014] The application also discloses a cylindrical lithium ion battery prepared by the method.

[0015] The production process method of the cylindrical lithium ion battery introduces the protection circuit board PCBA and the current interrupting device into the cylindrical lithium ion cell by designing the cap preparation process and the battery preparation process, solves a series of problems caused by the separation of the PACK process and the cell manufacturing in the prior art, can provide protection for battery charging and discharging, and improves the safety performance of the battery.

[0016] Other beneficial effects of the application will be described in the specific embodiments by introducing specific technical features and technical solutions, and those skilled in the art should understand the beneficial technical effects brought by the technical features and technical solutions. BRIEF DESCRIPTION OF DRAWINGS

[0017] The preferred embodiments of the production process method of the cylindrical lithium ion battery according to the application will be described below with reference to the accompanying drawings. In the drawings: Figure 1 It is a schematic diagram of the production process method of the cylindrical lithium ion battery according to a preferred embodiment of the application; Figure 2 It is a schematic diagram of the cap structure according to a preferred embodiment of the application; Figure 3 It is a schematic diagram of the cap with the built-in protection circuit board PCBA according to a preferred embodiment of the application; Figure 4 It is a schematic diagram of the battery roll core loaded into the steel shell according to a preferred embodiment of the application; Figure 5 It is a schematic diagram of the battery roll core after the negative electrode tab is welded to the bottom of the inside of the steel shell according to a preferred embodiment of the application; Figure 6 It is a schematic diagram of the steel shell groove formed after the steel shell is rolled according to a preferred embodiment of the application; Figure 7 It is a schematic diagram of the battery roll core after the positive electrode tab is welded to the current interrupting device of the cap according to a preferred embodiment of the application. DETAILED DESCRIPTION

[0018] In order to provide a more detailed description of the technical solution of the present application and to facilitate a further understanding of the present application, the specific implementation methods of the present application are described below in conjunction with the accompanying drawings. However, it should be understood that all illustrative embodiments and their descriptions are used to explain the present application and do not constitute the sole limitation of the present application.

[0019] Figure 1 The present invention is a schematic diagram of a production process for a cylindrical lithium-ion battery according to a preferred embodiment of the present invention, which includes a cap preparation process and a battery preparation process. The cap preparation process includes: Step 1: Place the positive electrode aluminum plate, positive electrode ring, insulating layer, protection circuit board PCBA and negative electrode ring in the sealing ring in sequence. The protection circuit board PCBA is used to control and prevent overcharging when the battery is charging and to control and prevent over-discharging when the battery is discharging. The protection circuit board PCBA is welded to the positive electrode ring, the positive electrode ring is in contact with the positive electrode aluminum plate, and the protection circuit board PCBA is welded to the negative electrode ring. In a specific embodiment, ultrasonic welding can be used to weld the protection circuit board PCBA to the positive electrode ring and the protection circuit board PCBA to the negative electrode ring. The positive electrode ring is in contact with the positive electrode aluminum plate and is close to it. When it is subsequently sealed, the two will be connected. If they are not close to each other, the internal resistance between the two will be very large, which may cause internal short circuits or defects in the battery.

[0020] Step 2: Weld the current interrupt device (CID) to the positive aluminum plate to complete the cap preparation. In the event of a battery cell failure, such as overheating, short circuiting, or overcharging, the CID generates a large amount of gas inside. When the pressure reaches a certain level (e.g., 1.4±0.2MPa for a cylindrical 14500 battery), the welds between the aluminum plate and the CID pressure relief plate separate, causing the pressure relief plate to flip, automatically severing the positive lead, preventing electrolyte leakage and ultimately disconnecting the battery cell internally, thus achieving a protective effect.

[0021] like Figure 2 As shown, the positive electrode aluminum plate 2 is first placed inside the sealing ring 1, followed by the positive electrode ring 3, insulation layer 4, protective circuit board PCBA 5, and negative electrode ring 6. The protective circuit board PCBA 5 is welded to the positive electrode ring 3, so that the positive electrode ring 3 contacts the positive electrode aluminum plate 2, and the protective circuit board PCBA 5 is welded to the negative electrode ring 6. The protective circuit board PCBA 5 includes an IC circuit 9. 8 is a metal stud welded to the protective circuit board PCBA 5, serving as the positive output of the battery. Finally, the current interrupter 7 is welded to the positive electrode aluminum plate 2, completing the capping process. Figure 3 The figure is a three-dimensional schematic diagram of a cap with a built-in protective circuit board PCBA manufactured by the above-mentioned cap manufacturing method.

[0022] The battery preparation process includes: Step one, positive and negative electrode batching. It includes positive electrode batching and negative electrode batching. Positive electrode batching is to mix various materials such as pretreated positive active material, binder, dispersant, conductive agent, solvent, etc. through a mixer, and screen the large particles of the slurry. Negative electrode batching is to mix various materials such as pretreated negative active material, binder, dispersant, conductive agent, solvent, etc. through a mixer, and screen the large particles of the slurry.

[0023] The preparation of positive electrode slurry needs to strictly follow the order, time and proportion of feeding, and control the speed of the equipment, the vacuum degree of stirring and the temperature. At this stage, the particle size and viscosity of the slurry should be detected regularly to ensure that it meets the process requirements. Under conventional process conditions, the temperature should be maintained at 30-45℃, the humidity should be less than or equal to 40% RH, and the vacuum degree should not exceed -0.85 MPa. Excessive particles may affect the coating quality of the battery, and even cause the risk of self-discharge or short circuit. The mesh size and particle size can be set according to the requirements.

[0024] The preparation of negative electrode slurry usually uses water-based mixing method, so the incoming material does not need to be dried. During the mixing process, the conductivity of deionized water needs to be strictly controlled to be less than or equal to 1 us / cm. At the same time, the workshop environment also needs to maintain a certain temperature and humidity range. Under conventional process conditions, the temperature should be maintained at 15-30℃, and the humidity should be less than or equal to 70% RH.

[0025] Step two, positive and negative electrode coating. The coating machine uniformly coats the slurry obtained in step one on the current collector, and is dried by a traveling dryer, and is wound into a roll by the auxiliary machine of the coating machine.

[0026] Step three, positive and negative electrode rolling. The dried roll is compacted by a rolling machine. Rolling can make the surface of the electrode sheet smooth and flat, reduce the volume of the electrode sheet, improve the energy density, improve the electronic conductivity, and enhance the bonding strength of the coating material and the current collector.

[0027] The commonly used rolling process includes hot pressing and cold pressing. The compaction effect of hot pressing process is relatively high, and the rebound rate is low, but the cold pressing process is simpler and easier to operate. During the rolling process, attention should be paid to key process values such as the surface density of the coating. For example, the surface density of the positive electrode coating needs to reach 40.2±0.4 mg / cm2, and the surface density of the negative electrode coating needs to reach 20±0.3 mg / cm2. At the same time, it is necessary to ensure that the surface of the electrode sheet is free of brittle pieces, hard blocks, falling materials or wavy edges, and the gap should not be broken.

[0028] Step four, positive and negative electrode slitting. Specifically, the positive and negative electrode sheets can be transported from the rolling machine to the electrode sheet continuous slitting machine by the roll stock transport vehicle for slitting, and the width of the roll stock is suitable. For example, the positive electrode slitting width can be 39.5±0.1mm, and the negative electrode slitting width can be 40.5±0.1mm. Through the slitting process, the battery cell can be cut into different widths and lengths according to the actual needs to adapt to the needs of different application scenarios.

[0029] Step five, positive and negative electrode sheet making. The sheet making process includes welding the slitting electrode sheet to the tab to provide a conductor for the battery, ensuring that the current can flow smoothly inside the battery.

[0030] In a specific embodiment, the positive and negative electrode slitting roll stock can be transported to the laser welding machine by the electrode sheet roll stock vehicle for welding the tab (aluminum tape or nickel-plated steel tape) and the adhesive (electrode sheet adhesive and tab adhesive).

[0031] Step six, positive and negative electrode winding to form a battery roll core. Specifically, the tab-welded and adhesive-applied roll stock can be transported to a circular full-automatic winding machine for assembly, including winding the positive and negative electrode roll stock, the separator, and the electrode sheet adhesive into a roll core. It is also necessary to detect whether the roll core is short-circuited, the relative humidity of the environment is ≤30%RH, and the temperature is 20-30℃. The winding process can accurately control the tension and other parameters of the winding according to the design requirements of the battery cell, so as to ensure that the battery cell has the required size and shape. For example, the positive electrode sheet has an entry segment tension of 0.08MPa, an initial segment tension of 0.1MPa, a middle segment tension of 0.125MPa, a post-stop and reversing tension of 0.125MPa, and a tension of 0.1MPa after stopping for 5 seconds. The negative electrode sheet has an entry segment tension of 0.08MPa, an initial segment tension of 0.1MPa, a middle segment tension of 0.125MPa, a post-stop and reversing tension of 0.125MPa, and a tension of 0.1MPa after stopping for 5 seconds. The entry segment tension of the separator is 0.06MPa, the initial segment tension is 0.1MPa, the middle segment tension is 0.125MPa, the post-stop and reversing tension is 0.125MPa, and the tension is 0.1MPa after stopping for 5 seconds. This helps to ensure that the battery cell can proceed smoothly in subsequent packaging, liquid injection, and other processes, and ultimately produce a lithium-ion battery that meets the requirements.

[0032] Under specific process conditions, the width of the negative electrode sheet should be 40.5±0.1mm, the width of the positive electrode sheet should be 39.5±0.1mm, and the width of the separator should be 42.5mm. The three should be accurately aligned to reduce the risk of short circuit. In addition, the environmental conditions in the workshop also have an important impact on the winding process.

[0033] Step seven, the battery roll core is installed in the steel shell, the negative electrode tab of the battery roll core is welded with the inside bottom of the steel shell, the steel shell is rolled, and the positive electrode tab of the battery roll core is welded with the current interrupt device of the cover cap, and the battery roll core connected with the cover cap is obtained. In a specific embodiment, the upper end and the lower end of the battery roll core can be padded with PE pads before being installed in the steel shell, which can prevent short circuit of the battery roll core. The negative electrode tab can be welded with the inside bottom of the steel shell by laser spot bottom welding. The positive electrode tab of the battery roll core can be welded with the current interrupt device of the cover cap by ultrasonic welding.

[0034] Figure 4 A schematic diagram for installing the battery roll core 11 in the steel shell 13, Figure 5 A schematic diagram for welding the negative electrode tab 12 of the battery roll core 11 with the inside bottom of the steel shell 13. The connection between the negative electrode tab and the steel shell is used as the negative electrode of the battery roll core. Figure 6 The position 14 indicated by the arrow is the steel shell groove formed after the steel shell 13 is rolled, Figure 7 A schematic diagram for welding the positive electrode tab 10 of the battery roll core 11 with the current interrupt device 7 of the cover cap. The positive electrode tab extends from the roll core and is connected with the current interrupt device. The current interrupt device 7 is connected with the positive electrode aluminum plate, and the positive electrode aluminum plate is connected with the positive electrode ring, which is used as the positive electrode of the battery roll core. One end of the current interrupt device 7 is connected with the positive electrode aluminum plate, and the other end is connected with the positive electrode tab of the roll core. When the battery roll core fails, the current interrupt device is disconnected under the action of increased internal pressure, and the battery is disconnected and no longer continues to charge, preventing safety accidents.

[0035] In a specific embodiment, spot bottom welding requires inserting a welding needle (usually made of copper or alloy material) into the middle hole of the battery roll core 11. The welding strength needs to reach or exceed 12N to ensure that the negative electrode tab can be stably welded and avoid false welding or excessive internal resistance. At the same time, attention should also be paid to not welding off the nickel layer on the surface of the steel shell 13 to prevent rust or liquid exposure at the welding point.

[0036] The purpose of rolling is to firmly fix the battery roll core 11 in the steel shell 13 to prevent shaking during use. This process requires precise control of the transverse extrusion speed and the pressure value of the downward pressure to avoid cutting the shell or causing the nickel layer of the groove to fall off. Usually, the transverse extrusion speed is 30-35mm / s, the downward pressure is 0.4MPa, and the commonly used rolling cutter specifications include 1.3-1.5mm.

[0037] Step eight, the battery cell is baked in a high vacuum oven. Specifically, the high vacuum oven is set to 90 degrees, the vacuum value is 50 Pa, the vacuum baking time is 10 minutes, the nitrogen baking time is 50 minutes, and the baking is cycled 6 times. Through this step, the moisture in the battery cell can be reduced, and the performance of the finished battery cell can be improved. Since the battery cell may bring in moisture during the manufacturing process, it is necessary to bake to ensure that the moisture is controlled within the standard range, thereby ensuring the performance and safety of the battery. Usually, this step is completed using an automatic vacuum oven, in which the battery cells to be baked are placed neatly and baked until the standard is reached. In addition, different sizes of battery cells have their own baking standards, which must be strictly followed.

[0038] Step nine, the baked battery cell is injected with electrolyte. The electrolyte is responsible for ion transmission in the battery. This step needs to be carried out in a vacuum glove box to ensure a clean and safe environment. The environment in the glove box needs to be strictly controlled, with a temperature below 23°C, a dew point below -45°C, and a humidity below 1% RH to ensure the accuracy and safety of the electrolyte injection process.

[0039] Step ten, the cap and steel shell are sealed by a sealing machine. One-seal, two-seal, and three-seal are a process of gradually pressing the battery, which can prevent the steel shell from breaking. In this scheme, squat sealing is not required, as squat sealing may cause the positive and negative terminals to be connected, resulting in a short circuit.

[0040] Step eleven, the battery cell is cleaned and rust-proofed by soaking in alkaline water and rust-proof oil. The dust, oil, and electrolyte remaining on the outside of the battery cell are cleaned. Specifically, the battery cell can be placed in 50-degree alkaline water for 3-5 minutes, then drained, then placed in an oven for 15-30 minutes, and finally coated with rust-proof oil.

[0041] Step twelve, a plastic outer film is added to the outside of the battery cell. It can be a PVC or PET plastic outer film. This reduces the risk of short circuiting the battery cell and optimizes the appearance.

[0042] Step thirteen, the battery cell is activated with a small current to charge the battery cell to a first voltage, and the small current is 20-100 mA. Specifically, the first voltage can be 3.6 V.

[0043] Step fourteen, the battery cell is subjected to a preset time formation process, and the preset time is less than or equal to 3 hours.

[0044] Step fifteen, the battery cell is subjected to a capacity sorting process to obtain lithium ion cylindrical batteries of different capacities.

[0045] The production process method of the cylindrical lithium ion battery of the application introduces the protection circuit board PCBA and the current interrupt device into the cylindrical lithium ion cell through the design of the cap preparation process and the battery preparation process, solves a series of problems caused by the separation of the PACK process and the cell manufacturing in the prior art, can provide protection for the charging and discharging of the battery, and improves the safety performance of the battery. In addition, the cell connected with the cap is directly activated in the battery manufacturing process, which reduces the scrap rate of the battery and shortens the production process. The formation time is shortened, and the production efficiency is improved.

[0046] In a preferred embodiment, the welding of the protection circuit board PCBA and the negative electrode ring in step one of the cap preparation process comprises that the negative electrode ring serves as the negative electrode of the protection circuit board PCBA.

[0047] In a preferred embodiment, the positive electrode ring in step one of the cap preparation process serves as a positive temperature coefficient thermistor (PTC, Positive Temperature Coefficient), which controls the stop of charging when the charging current is greater than a preset value, and controls the stop of discharging when the discharging current is greater than the preset value. The PTC thermistor is a typical semiconductor resistor with temperature sensitivity. When the temperature exceeds a certain value, the resistance value of the PTC thermistor increases step by step with the increase of the temperature. When the charging current or the discharging current is too large, the temperature of the positive electrode ring increases, the resistance value increases step by step, and the resistance value is very large, which controls the stop of charging or discharging.

[0048] In a specific embodiment, the preset value can be set according to the demand and the performance of the device, for example, 10A.

[0049] At the same time, by controlling the thickness of the positive electrode ring in the longitudinal direction, the short circuit between the electronic components on the protection circuit board PCBA and the positive electrode aluminum plate can also be prevented. In addition, by controlling the inner diameter of the positive electrode ring, the short circuit between the positive electrode ring and the electronic components on the protection circuit board PCBA can also be prevented.

[0050] In a preferred embodiment, in step two of the battery manufacturing process, the surface temperature of the positive electrode coated electrode sheet is 125-145°C (oil-based), the appearance of the positive electrode sheet requires no missing material and no particles, the gap error is ±1 mm (gap coating), the tailing error is less than 2 mm (gap coating), and the total error of the electrode sheet is ±1 mm. The electrode sheet thickness is measured within 5 mm from both sides, the error of the single-sided electrode sheet thickness in the transverse and longitudinal directions is ±2 um, and the error of the double-sided electrode sheet thickness in the transverse and longitudinal directions is ±3 um. The surface temperature of the negative electrode coated electrode sheet is 90-110°C (water-based), the appearance of the negative electrode sheet requires no missing material and no particles, the gap error is ±1 mm (gap coating), the tailing error is less than 2 mm (gap coating), and the total error of the electrode sheet is ±1 mm. The electrode sheet thickness is measured within 5 mm from both sides, the error of the single-sided electrode sheet thickness in the transverse and longitudinal directions is ±2 um, and the error of the double-sided electrode sheet thickness in the transverse and longitudinal directions is ±3 um.

[0051] In a preferred embodiment, step five of the battery manufacturing process includes: sending the positive and negative electrode slitting and coiling material obtained in step four to a laser welding machine to weld the tabs and apply adhesive, the tabs are aluminum strips or nickel-plated steel strips, and the adhesive includes electrode sheet adhesive and tab adhesive. Typically, the positive and negative electrode slitting and coiling material is sent to a laser welding machine to weld the tabs and apply adhesive.

[0052] In a preferred embodiment, step six of the battery manufacturing process includes: winding the separator, electrode sheet adhesive, and positive and negative electrode sheets obtained in step five to form the battery roll core, the winding environment has a relative humidity of less than or equal to 30% RH and a temperature of 20-30°C. Typically, the separator, electrode sheet adhesive, and positive and negative electrode sheets are sent to a circular full-automatic winding machine for winding.

[0053] In a preferred embodiment, the battery preparation process step fourteen includes: first trickle charging the battery cell with a first preset range of current value for one hour; then trickle charging the battery cell with a second preset range of current value for one hour; finally, trickle charging the battery cell with a third preset range of current value for one hour; checking the voltage of the cylindrical lithium ion battery in the cabinet, if the voltage is the second voltage, it is judged that the cylindrical lithium ion battery meets the requirements, and the cylindrical lithium ion battery is screened out. In a specific embodiment, the first preset range of current value can be 20mA-40mA, the second preset range of current value can be 40mA-100mA, the third preset range of current value can be 100mA-200mA, and the second voltage is 1.5V. The voltage of each battery is checked by the formation cabinet, and if it reaches the second voltage, it is considered to be qualified, otherwise it is unqualified. Specifically, after the battery cell is activated in step thirteen, the battery cell voltage reaches 3.6V. Due to the control of the protection circuit board PCBA, when the battery cell voltage is lower than 3.0V, the battery output is 0V, and when the battery cell voltage is greater than or equal to 3.0V, the battery voltage output is 1.5V. Therefore, the qualified cylindrical lithium ion battery cabinet voltage should be 1.5V.

[0054] In a preferred embodiment, the battery preparation process step fifteen includes: charging the battery cell to a fourth voltage with a fourth preset range of current value, standing for a preset time; then discharging the battery cell to a fifth voltage with the fourth preset range of current value, the cutoff current being a first current value; finally, charging the battery cell back to the fourth voltage with the fourth preset range of current value, thereby distinguishing the capacity of the cylindrical lithium ion battery. In a specific embodiment, the fourth preset range of current value is 100mA-1000mA, the fourth voltage is 4.6V, the preset time can be 5 minutes, the fifth voltage is 1.0V, and the first current value is 10mA. Specifically, after the battery cell is activated in step thirteen, the battery cell voltage reaches 3.6V, and the battery cell is continued to be formed in step fourteen. Therefore, before capacity grading, the battery cell voltage may reach about 3.75V.

[0055] In a preferred embodiment, the positive aluminum plate in the cap is arranged at the bottom of the inner side of the sealing ring, the positive ring is arranged in the sealing ring and in contact with the positive aluminum plate, the insulating layer is arranged at the bottom of the inner side of the positive ring and adjacent to the positive aluminum plate, and the insulating layer prevents the IC circuit system components from contacting and short-circuiting with the positive aluminum plate. The protection circuit board PCBA is arranged above the insulating layer, the negative ring is arranged at the outer edge of the upper end of the protection circuit board PCBA, and the current interrupting device is arranged outside the positive aluminum plate, which is the side of the positive aluminum plate facing the battery roll core.

[0056] In a preferred embodiment, the protection circuit board PCBA has an input face and an output face, the input face is the face connected with the positive electrode signal of the positive electrode tab of the battery core (for example Figure 7 the positive electrode tab in the positive electrode ring is connected with the PCBA through the CID), and the output face is the face of the protection circuit board PCBA plate having the positive electrode output (for example Figure 2 the five metal columns 8) of the cylindrical lithium ion battery, the protection circuit board PCBA is arranged inside the positive electrode ring, the input face of the protection circuit board PCBA faces the insulating layer, and the negative electrode ring is welded on the output face of the protection circuit board PCBA. The negative electrode ring is welded on the output face of the PCBA plate, and when the sealing is sealed in step ten, the sealing can prevent the sealing from being damaged or cracked by the PCBA plate, so that the contact resistance is lower.

[0057] The application further discloses a cylindrical lithium ion battery prepared by the method.

[0058] Those skilled in the art can understand that the above-mentioned preferred embodiments can be freely combined and superimposed without conflict.

[0059] It should be understood that the above-mentioned embodiments are only exemplary and not restrictive, and those skilled in the art can make various obvious or equivalent modifications or replacements to the above-mentioned details without departing from the essential principles of the application, which shall be included in the scope of the claims of the application.

Claims

1. A production process for cylindrical lithium-ion batteries, characterized in that: include: Cap preparation process: Step 1: Place the positive electrode aluminum plate, positive electrode ring, insulation layer, protection circuit board PCBA, and negative electrode ring in the sealing ring in sequence. The protection circuit board PCBA is used to control and prevent overcharging when the battery is charged and to control and prevent over-discharging when the battery is discharged. The protection circuit board PCBA is welded to the positive electrode ring, the positive electrode ring contacts the positive electrode aluminum plate, and the protection circuit board PCBA is welded to the negative electrode ring. Step 2: Welding the current interrupt device to the positive aluminum plate to complete the cap preparation; Battery preparation process: Step 1: Prepare the positive and negative electrode ingredients; Step 2: coating the positive and negative electrodes; Step 3: Rolling the positive and negative electrodes; Step 4: Separate the positive and negative electrodes; Step 5: Preparation of positive and negative electrodes; Step 6: Wind the positive and negative electrodes to form a battery core; Step 7: Place the battery core into a steel case, weld the negative electrode tab of the battery core to the inner bottom of the steel case, groove the steel case, and weld the positive electrode tab of the battery core to the current interruption device in the cap to obtain a battery cell connected to the cap. Step 8: baking the battery cell in a high vacuum oven; Step nine, injecting electrolyte into the baked battery cell; Step 10: The cap and the steel shell are put through a sealing machine for one, two, or three sealing processes; Step 11: Clean and prevent rust of the battery cell by soaking it in alkaline water and anti-rust oil; Step 12: Covering the battery core with a plastic outer film; Step 13: activating the battery cell with a small current to charge the battery cell to a first voltage, wherein the small current is 20 to 100 mA; Step 14: performing a formation treatment on the battery cell for a preset time, wherein the preset time is less than or equal to 3 hours; Step 15: performing capacity separation processing on the battery cells to obtain lithium-ion cylindrical batteries of different capacities.

2. The production process of cylindrical lithium-ion batteries according to claim 1, characterized in that: The positive electrode ring in step 1 of the cap preparation process is used as a positive temperature coefficient thermistor. When the charging current is greater than a preset value, the positive temperature coefficient thermistor controls the charging to stop; When the discharge current is greater than the preset value, the positive temperature coefficient thermistor controls the discharge to stop.

3. The production process of cylindrical lithium-ion batteries according to claim 1, characterized in that: In the second step of the battery preparation process, The surface temperature of the positive electrode coated electrode is 125-145℃. The appearance of the positive electrode after coating is required to be free of missing materials and particles, with a gap error of ±1mm, a tailing error of less than 2mm, a total electrode error of ±1mm, and a thickness measurement within 5mm from both sides. The horizontal and vertical single-sided electrode thickness error is ±2um, and the horizontal and vertical double-sided electrode thickness error is ±3um. The surface temperature of the negative electrode coated electrode is 90-110℃. The appearance of the negative electrode after coating is required to be free of missing materials and particles, the gap error is ±1mm, the tailing error is less than 2mm, the total error of the electrode is ±1mm, the thickness of the electrode is measured within 5mm from both sides, the horizontal and vertical single-sided electrode thickness error is ±2um, the horizontal and vertical double-sided electrode thickness error is ±3um.

4. The production process of cylindrical lithium-ion batteries according to claim 1, characterized in that: The battery preparation process step five of positive and negative electrode preparation includes: The positive and negative electrode strips obtained in step 4 are welded to the tabs and glued. The tabs are aluminum strips or nickel-plated steel strips, and the glue includes electrode sheet glue and tab glue.

5. The production process of cylindrical lithium-ion batteries according to claim 1, characterized in that: The battery preparation process step six of positive and negative electrode winding includes: The separator, the electrode glue and the positive and negative electrode sheets obtained in step five are wound into the battery core. The relative humidity of the winding environment is less than or equal to 30% RH and the temperature is 20-30°C.

6. The production process of cylindrical lithium-ion batteries according to claim 1, characterized in that: The battery preparation process step 14 includes: Performing trickle charging on the battery cell at a current value within a first preset range for one hour; Then, trickle charging the battery cell at a current value within a second preset range for one hour; Finally, the battery cell is trickle charged at a current value within a third preset range for one hour; The cabinet checks whether the voltage of the cylindrical lithium-ion battery is the second voltage. If so, it is determined that the cylindrical lithium-ion battery meets the requirements and the cylindrical lithium-ion battery is screened out.

7. The production process of cylindrical lithium-ion batteries according to claim 6, characterized in that: The fifteenth step of the battery preparation process includes: charging the battery cell to a fourth voltage with a current value within a fourth preset range, and leaving the battery cell to stand for a preset time; Then, discharging the battery cell to a fifth voltage at a current value within the fourth preset range, with a cut-off current being the first current value; Finally, the battery cell is recharged to the fourth voltage with a current value within the fourth preset range, thereby distinguishing the capacity of the cylindrical lithium-ion battery.

8. The production process for cylindrical lithium-ion batteries according to any one of claims 1 to 7, characterized in that: The positive aluminum plate is arranged at the bottom of the inner side of the sealing ring; The positive electrode ring is arranged in the sealing ring; The insulating layer is arranged on the inner side of the positive electrode ring and is adjacent to the positive electrode aluminum plate; The protection circuit board PCBA is arranged above the insulation layer; The negative electrode ring is arranged on the outer edge of the upper end of the protection circuit board PCBA; The current interruption device is arranged on the outer side of the positive aluminum plate, and the outer side is the side of the positive aluminum plate facing the battery coil core.

9. The production process of cylindrical lithium-ion batteries according to claim 8, characterized in that: The protection circuit board PCBA has an input surface and an output surface, the input surface is the surface to which the positive electrode electrical signal of the positive electrode tab of the battery core is connected, and the output surface is the surface of the protection circuit board PCBA board with the positive electrode output of the cylindrical lithium-ion battery; The protection circuit board PCBA is arranged inside the positive electrode ring, with the input surface of the protection circuit board PCBA facing the insulating layer, and the negative electrode ring is welded to the output surface of the protection circuit board PCBA.

10. A cylindrical lithium-ion battery, characterized in that: The method is prepared by any one of claims 1 to 9.

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