CN116914266A - Lithium ion cylindrical battery assembling and open drying method - Google Patents
Lithium ion cylindrical battery assembling and open drying method Download PDFInfo
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- CN116914266A CN116914266A CN202310863434.3A CN202310863434A CN116914266A CN 116914266 A CN116914266 A CN 116914266A CN 202310863434 A CN202310863434 A CN 202310863434A CN 116914266 A CN116914266 A CN 116914266A
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- electrode cover
- baking
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- 238000001035 drying Methods 0.000 title claims abstract description 70
- HBBGRARXTFLTSG-UHFFFAOYSA-N Lithium ion Chemical compound [Li+] HBBGRARXTFLTSG-UHFFFAOYSA-N 0.000 title claims abstract description 22
- 229910001416 lithium ion Inorganic materials 0.000 title claims abstract description 22
- 238000003466 welding Methods 0.000 claims abstract description 71
- 238000000034 method Methods 0.000 claims abstract description 29
- 238000007493 shaping process Methods 0.000 claims abstract description 18
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims description 67
- 238000012360 testing method Methods 0.000 claims description 47
- 239000001307 helium Substances 0.000 claims description 39
- 229910052734 helium Inorganic materials 0.000 claims description 39
- SWQJXJOGLNCZEY-UHFFFAOYSA-N helium atom Chemical compound [He] SWQJXJOGLNCZEY-UHFFFAOYSA-N 0.000 claims description 39
- 229910052757 nitrogen Inorganic materials 0.000 claims description 34
- 238000001514 detection method Methods 0.000 claims description 20
- 230000002093 peripheral effect Effects 0.000 claims description 19
- 238000001291 vacuum drying Methods 0.000 claims description 15
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 claims description 10
- 229910052782 aluminium Inorganic materials 0.000 claims description 10
- 238000007689 inspection Methods 0.000 claims description 7
- 230000008569 process Effects 0.000 abstract description 17
- 238000004519 manufacturing process Methods 0.000 abstract description 12
- 238000005265 energy consumption Methods 0.000 abstract description 8
- 230000000694 effects Effects 0.000 abstract description 6
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 11
- 239000007789 gas Substances 0.000 description 10
- 238000002347 injection Methods 0.000 description 10
- 239000007924 injection Substances 0.000 description 10
- 239000007788 liquid Substances 0.000 description 8
- 238000005452 bending Methods 0.000 description 6
- 230000007306 turnover Effects 0.000 description 5
- 230000000052 comparative effect Effects 0.000 description 4
- 238000001125 extrusion Methods 0.000 description 4
- 238000010438 heat treatment Methods 0.000 description 3
- GELKBWJHTRAYNV-UHFFFAOYSA-K lithium iron phosphate Chemical compound [Li+].[Fe+2].[O-]P([O-])([O-])=O GELKBWJHTRAYNV-UHFFFAOYSA-K 0.000 description 3
- 230000007246 mechanism Effects 0.000 description 3
- 238000005070 sampling Methods 0.000 description 3
- KRHYYFGTRYWZRS-UHFFFAOYSA-N Fluorane Chemical compound F KRHYYFGTRYWZRS-UHFFFAOYSA-N 0.000 description 2
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 description 2
- 238000001816 cooling Methods 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 238000007599 discharging Methods 0.000 description 2
- 239000003792 electrolyte Substances 0.000 description 2
- 206010016766 flatulence Diseases 0.000 description 2
- 229910052744 lithium Inorganic materials 0.000 description 2
- 230000002159 abnormal effect Effects 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 239000007772 electrode material Substances 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- QJGQUHMNIGDVPM-UHFFFAOYSA-N nitrogen group Chemical group [N] QJGQUHMNIGDVPM-UHFFFAOYSA-N 0.000 description 1
- 238000005457 optimization Methods 0.000 description 1
- 238000003825 pressing Methods 0.000 description 1
- 238000007789 sealing Methods 0.000 description 1
- 239000002893 slag Substances 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- 238000004804 winding Methods 0.000 description 1
Classifications
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F26—DRYING
- F26B—DRYING SOLID MATERIALS OR OBJECTS BY REMOVING LIQUID THEREFROM
- F26B9/00—Machines or apparatus for drying solid materials or objects at rest or with only local agitation; Domestic airing cupboards
- F26B9/06—Machines or apparatus for drying solid materials or objects at rest or with only local agitation; Domestic airing cupboards in stationary drums or chambers
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F26—DRYING
- F26B—DRYING SOLID MATERIALS OR OBJECTS BY REMOVING LIQUID THEREFROM
- F26B5/00—Drying solid materials or objects by processes not involving the application of heat
- F26B5/04—Drying solid materials or objects by processes not involving the application of heat by evaporation or sublimation of moisture under reduced pressure, e.g. in a vacuum
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M10/00—Secondary cells; Manufacture thereof
- H01M10/05—Accumulators with non-aqueous electrolyte
- H01M10/052—Li-accumulators
- H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M10/00—Secondary cells; Manufacture thereof
- H01M10/05—Accumulators with non-aqueous electrolyte
- H01M10/058—Construction or manufacture
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/10—Energy storage using batteries
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
- Y02P70/50—Manufacturing or production processes characterised by the final manufactured product
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- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Electrochemistry (AREA)
- Manufacturing & Machinery (AREA)
- General Engineering & Computer Science (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Mechanical Engineering (AREA)
- General Chemical & Material Sciences (AREA)
- Health & Medical Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Molecular Biology (AREA)
- Materials Engineering (AREA)
- Secondary Cells (AREA)
Abstract
The application discloses a lithium ion cylindrical battery assembling and open drying method, which comprises the following steps: s1, shaping positive and negative cover plates of a battery; s2, welding a negative electrode cover plate of the battery, and opening a positive electrode cover plate; s3, drying the battery in the step S2; and S4, taking out the dried battery in the step S3, and welding the positive electrode cover plate. According to the cylindrical battery assembling and open drying method, the assembling process is optimized, so that the positive and negative electrode cover plates can be welded in a distributed manner, and the battery cells are dried in an open state when baked, so that the moisture in the baking process is conveniently discharged, and the conventional common use is that the finished battery cells are baked, and the time and the energy consumption are high; or further baking the bare cell, so that the cell is easy to damage and discard; the application utilizes the shell of the battery core to provide protection for the battery core, and the scheme of maintaining the opening and increasing the baking effect needs to be matched with the adjustment of the assembly step. The production efficiency is improved, and the production cost is reduced.
Description
Technical Field
The application relates to the technical field of battery assembly, in particular to a lithium ion cylindrical battery assembly and an open drying method.
Background
At present, the assembly process of the large cylindrical batteries with the diameter of 32mm and 46mm is as follows: the process of winding the pole piece, rubbing the full tab (rubberizing), putting the bare cell into the shell, welding the current collecting disc, welding the periphery of the cover plate (pre-welding) and testing the hipot (high potential test electrical safety stress test dielectric withstand voltage test), helium checking, baking the cell and testing the hipot is unfavorable for discharging the moisture of the cell. In the production of lithium ion batteries, moisture is one of the important factors affecting the performance and quality of the batteries. The lithium ion power battery for the passenger car has stricter standards for the safety, the service life and the like of the battery; the electrolyte used by the lithium battery is easy to chemically react with water to generate hydrofluoric acid, the anode and the cathode of the battery are corroded, and the battery core is caused to generate abnormal phenomena such as flatulence, so that the water content of the battery electrode group before liquid injection is strictly controlled in the production process, the water content is always up to a certain standard through battery baking, and when the water content of the battery exceeds the standard before liquid injection, the performance of the finished battery is rapidly reduced until serious flatulence of the battery occurs, and the battery is scrapped. Therefore, in the production process of the lithium ion battery, the electrode material, the electrode plate or the battery core needs to be baked and dried to control the moisture in a certain range, and the temperature and the humidity of the production environment need to be strictly controlled. The materials for the electrode and the water in the pole piece can be heated and discharged, and the process difficulty is low. The assembled battery cell only exchanges gas with the outside through the liquid injection hole, but the opening reserved on the shell for injecting electrolyte is very small, the positive plate, the negative plate and the diaphragm in the shell are tightly wound, and the water in the battery cell is difficult to discharge from the shell.
In the prior art, the battery cell is dried by adopting vacuum drying, in order to remove the moisture in the battery and achieve the purpose of drying, the battery assembly is mainly heated and baked for a long time, but the assembled cylindrical battery only exchanges gas with the outside through a liquid injection hole with the diameter of about 2mm, the processes of vacuumizing an oven, filling nitrogen and the like are applied to the inside of the battery cell for a certain time and have a certain deviation from the inside of the box body, so that the efficiency is low, the energy consumption is high, and the drying effect is not ideal; therefore, the baking and drying method of the battery cell after the battery cell is put into the shell is further optimized, so that the water content of the battery cell is lower, the baking efficiency is higher, the nitrogen consumption and the energy consumption of baking equipment are reduced, and the method becomes an important optimization direction for lithium battery production.
Publication number CN105470463A discloses a lithium ion power battery pole piece drying turnover device and method. The application is that the pole pieces to be dried are placed into the pole piece turnover device vertically to the bottom side of the drying turnover device, and the pole pieces are separated by upright posts; after the temperature of the drying box rises, placing a drying turnover device for containing the pole pieces into a vacuum drying box; if the space allows, putting a plurality of drying turnover devices into a drying box together; and the moisture in the pole piece is taken away through the circulation of the air of the vacuum drying box. However, this application does not disclose a specific structure of how to accelerate drying efficiency on a battery basis, and does not disclose the above-mentioned problems.
Disclosure of Invention
The technical problems to be solved by the application are as follows: the method solves the problems of low efficiency and unsatisfactory drying effect of the traditional battery cell drying method.
In order to solve the technical problems, the application provides the following technical scheme:
a lithium ion cylindrical battery assembling and open drying method comprises the following steps:
s1, shaping positive and negative cover plates of a battery;
s2, welding a negative electrode cover plate of the battery, and opening a positive electrode cover plate;
s3, drying the battery in the step S2;
and S4, taking out the dried battery in the step S3, and welding the positive electrode cover plate.
The advantages are that: according to the cylindrical battery assembling and open drying method, the assembling process is optimized, the step-by-step welding of the anode cover plate and the cathode cover plate can be realized, and when the battery cell is baked, the battery cell is dried in an open state, so that the water in the baking process is conveniently discharged, and the baking of the finished battery cell is commonly used at present, and the time and the energy consumption are relatively high; or further baking the bare cell, so that the cell is easy to damage and discard; the application utilizes the shell of the battery core to provide protection for the battery core, and the scheme of maintaining the opening and increasing the baking effect needs to be matched with the adjustment of the assembly step. The application has more convenient exchange with external gas, can obtain lower water content in shorter time, and has more ideal drying effect. The production efficiency is improved, and the production cost is reduced.
Preferably, the drying method further comprises the steps of:
s5, primary helium detection and resistance test: and (5) performing helium detection and a hipot test after the peripheral welding of the positive electrode cover plate is finished.
Preferably, the shaping step of the step S1 includes: and (3) carrying out three-stage shaping on the anode cover plate and the cathode cover plate after welding the current collecting disc, so that the alignment degree of the cover plate and the central shaft of the aluminum shell is kept to be +/-1 mm.
Preferably, the welding step of the step S2 includes: and closing the cover, pre-welding and peripheral welding are carried out on the negative electrode cover plate, and meanwhile, the positive electrode cover plate is pre-closed, so that welding is not needed.
Preferably, the drying step of step S3 includes:
s31, feeding the plates, wherein the opening of the anode cover plate is upward, and the plates enter an oven;
s32, preheating the battery cell, wherein the battery cell is preheated to 80-100 ℃ in a normal air atmosphere, and the preheating time is 80-120 min;
s33, vacuum drying, vacuumizing to 50-200 pa, and baking for 30-120min;
s34, drying by nitrogen, then charging 60-80 kpa of nitrogen, carrying out wind circulation for 10-20 min, and repeating the circulation of S33 and S34 for 6-10 times;
and S35, maintaining the pressure, discharging from a warehouse, vacuumizing to 50-200 Pa for 3min after baking, then filling nitrogen to 101kpa, and maintaining the pressure for 3min to finish baking.
Preferably, when the battery cover plate is welded, the anode cover plate and the cathode cover plate are welded step by step, and in the first step, the anode cover plate is only subjected to cover closing, pre-spot welding and peripheral welding, and meanwhile, the anode cover plate is subjected to cover closing.
Preferably, the welding conditions of the battery positive electrode cover plate in the step S4 are as follows: and after the baking of the battery is finished and the moisture test is qualified, the battery is placed in a drying workshop, the dew point in the drying workshop is less than or equal to-40 ℃, the temperature is 25+/-3 ℃, and the periphery of the battery anode cover plate is welded.
Preferably, dry helium is used for helium detection of the battery after welding of the positive electrode cover plate, and the battery is filled with the dry helium after helium detection, so that the battery is kept inside the battery to protect the battery without being pumped out.
Preferably, helium inspection is also completed within 30 minutes after welding of the positive electrode cover plate, and the helium inspection is synchronously performed in a hipot test, and the workshop conditions are as follows: the dew point is less than or equal to-40 ℃, the temperature is 25+/-3 ℃, the baking is carried out until the helium inspection is finished in a drying workshop, and the total use time is not more than 1H.
Preferably, after the step S3, the positive electrode cover plate is directly taken out of the warehouse for welding.
Compared with the prior art, the application has the beneficial effects that:
(1) The application can realize the step-by-step welding of the anode cover plates and the cathode cover plates by optimizing the assembly process, can avoid the mutual extrusion interference of the anode cover plates and the cathode cover plates in the welding process, has the problem of joint seam clearance, avoids the defects of laser scalding, welding slag entering, track deviation and the like, and has important improvement on peripheral welding; optimizing the existing post-peripheral welding hipot test in the industry as a post-baking hipot test after helium detection, and baking a finished product cell, wherein the existing common use is that the time and the energy consumption are relatively high; or further baking the bare cell, so that the cell is easy to damage and discard; the application utilizes the shell of the battery core to provide protection for the battery core, and the scheme of maintaining the opening and increasing the baking effect needs to be matched with the adjustment of the assembly step. And the production efficiency is improved.
(2) According to the application, through optimizing the baking method, the battery cell is dried in an open state, so that the moisture is conveniently discharged in the baking process, and the nitrogen flow in the oven directly contacts the battery cell electrode group during the nitrogen air circulation, so that the battery cell is more convenient to exchange with external air only through the liquid injection hole with the diameter of 2mm compared with the original battery cell, and the lower water content is obtained in a shorter time; the preheating stage is directly carried out in an air atmosphere, the air heat conductivity coefficient 0.0233 is higher than that of nitrogen by 0.0228, the nitrogen consumption and the replacement time are saved, the production efficiency is further improved, the energy consumption is reduced, and the cost is saved.
Drawings
FIG. 1 is a schematic illustration of an assembly process according to a first embodiment of the present application;
FIG. 2 is a schematic diagram of an open baking process according to a first embodiment of the present application;
fig. 3 is a schematic view of a battery structure with a cover plate shaped according to a first embodiment of the application;
fig. 4 is a schematic view of a battery structure after welding a negative electrode cover plate according to the first embodiment of the application;
fig. 5 is a schematic diagram of a battery cell tray according to a first embodiment of the present application;
FIG. 6 is a graph showing the comparison of test moisture for examples two, three and comparative example one of the present application;
in the figure: 1. a battery; 11. a positive electrode cover plate; 12. a negative electrode cover plate; 2. and (5) assembling a disc.
Detailed Description
In order to facilitate the understanding of the technical scheme of the present application by those skilled in the art, the technical scheme of the present application will be further described with reference to the accompanying drawings.
The terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include one or more such feature. In the description of the present application, the meaning of "a plurality" is two or more, unless explicitly defined otherwise.
Example 1
Referring to fig. 1 and 2, the embodiment discloses a lithium ion cylindrical battery assembling and opening drying method, which comprises the following steps:
s1, shaping the positive cover plate and the negative cover plate of the battery 1. Specifically, the battery 1 after welding the current collecting disc performs three-stage shaping on the anode cover plate 12 so that the alignment degree of the cover plate and the central axis of the aluminum shell is kept to be +/-1 mm. In the embodiment, the alignment degree between the cover plate and the central axis of the aluminum shell is kept +/-1 mm, so that the follow-up normal closing of the cover is ensured.
S2, welding the negative electrode cover plate 12 of the battery 1, and opening the positive electrode cover plate 11. Specifically, the negative electrode cover plate 12 is covered, pre-spot welded, and peripheral welded, and the positive electrode cover plate 11 is pre-covered at the same time, and welding is not necessary. According to the embodiment, the negative electrode cover plate 12 of the battery 1 is welded, the positive electrode cover plate 11 is opened, and the positive electrode cover plate 11 is provided with the liquid injection port, so that the battery can be placed upwards, and gas can be conveniently discharged and liquid can be injected subsequently. In this step, the pre-closing cover of the positive electrode cover plate 11 can be arranged in a certain clearance, so that the phenomenon that the negative electrode cover plate 12 is poorly welded due to mutual extrusion interference caused by simultaneous pressing force of the positive electrode cover plate 12 and the negative electrode cover plate 12 is avoided. And the opening of the positive electrode cover plate 11 can ensure that the inside and the outside of the battery 1 are fully contacted, so that the subsequent drying of the battery 1 is facilitated.
And S3, drying the battery 1 in the step S2. Referring to fig. 2 to 5, the drying step of step S3 includes:
s31, feeding the tray 2, opening the anode cover plate 11 upwards, and feeding the tray 2 into the oven.
S32, preheating the battery cell, wherein the battery cell is preheated to 80-100 ℃ in a normal air atmosphere, and the preheating time is 80-120 min.
S33, vacuum drying, vacuumizing to 50-200 pa, and baking for 30-120min.
S34, drying by nitrogen, then charging 60-80 kpa of nitrogen, carrying out wind circulation for 10-20 min, and repeating the steps S33 and S34 for 6-10 times.
S35, maintaining the pressure, leaving the warehouse, vacuumizing to 50-200 pa after baking, wherein the maintaining time is 2-5min, the preferred time of the embodiment is 3min, then filling nitrogen to the atmospheric pressure, and maintaining the pressure for 2-5min to finish baking, wherein the preferred time of the embodiment is 3min.
In this step S3, since nitrogen substitution is not required in the baking and preheating stage, the temperature-raising and preheating can be directly performed in an atmospheric air atmosphere. And after baking, the anode cover plate 11 is directly taken out of the warehouse for welding without a cooling step. The positive electrode cover plate 11 is always kept in an open state when the battery cells are dried.
And S4, taking out the dried battery 1 in the step S3, and welding the positive electrode cover plate 11.
Specifically, after the baking of the battery 1 is completed and the moisture test is qualified, the battery 1 is placed in a drying workshop within 30 minutes, and the periphery of the positive electrode cover plate 11 of the battery 1 is welded. Wherein, the conditions of the drying workshop are: the dew point is less than or equal to-40 ℃ and the temperature is 25+/-3 ℃.
S5, primary helium detection and resistance test: after the welding of the periphery of the positive electrode cover plate 11 is completed, helium test and hipot test are performed.
Specifically, dry helium is required to be used for helium detection of the battery 1 after welding of the positive electrode cover plate 11 is completed, and the battery 1 is filled with dry helium after the helium detection is completed, so that the battery 1 is kept inside the battery 1 to protect the battery 1 without being pumped out. Helium inspection is also required to be completed within 0-30min after the welding of the anode cover plate 11 is completed, and the helium inspection is synchronously performed with a hipot test, so that the helium inspection is performed in a drying workshop after being baked out of the oven, and the total use time is not more than 1H. Wherein, the conditions of workshop are: the dew point is less than or equal to-40 ℃ and the temperature is 25+/-3 ℃.
According to the embodiment, through parameters matched with the open state, the baking time can be saved, and the energy consumption and the nitrogen consumption can be reduced.
The drying method of the present embodiment is suitable for the assembly of large cylindrical batteries 1 having diameters of 32mm, 46mm, etc. and the drying process thereof.
Example two
The embodiment is a large-cylinder lithium ion assembly drying method which is carried out by adopting an IFR32135-15Ah lithium iron phosphate cylindrical cell and a high-temperature baking mode. The method comprises the following steps:
s1: shaping a cover plate: after the bare cell is put into the aluminum shell, the anode and cathode current collecting plates are welded respectively, and after the current collecting plates are welded, the anode and cathode cover plate 12 is subjected to three-stage shaping of pre-bending, 90-degree bending and pre-closing through the equipment shaping mechanism, so that the alignment degree of the cover plate and the center shaft of the aluminum shell is kept within +/-1 mm.
S2: welding the cathode cover plate 12: the negative electrode cover plate 12 is jacked and covered, and is fixed by three pre-spot welding points, then the welding of the negative electrode cover plate 12 is completed by peripheral welding, and meanwhile, the end face of the positive electrode cover plate 11 is required to be in a clearance setting, so that the interference of forced extrusion to the welding of the negative electrode cover plate 12 is avoided, and the positive electrode cover plate 11 is not welded in the step, so that the pre-covered state is maintained.
S3: the tray 2 is baked, and the baking process steps are as follows: (1) group tray 2 feed: after the peripheral welding of the negative electrode cover plate 12 is finished, the state of the battery 1 is adjusted to the state that the positive electrode cover plate 11 faces upwards, and 512ea batteries 1 form a tray and enter an oven; (2) preheating the battery cell: after the oven is closed, the baking temperature is set to 95 ℃ and is directly heated for 100min, so that the temperature of the battery cell is increased by 95 ℃; (3) vacuum drying: vacuumizing the air in the box body to 100Pa after preheating is finished, and continuously baking for 45min at 95 ℃; (4) drying with nitrogen: after the vacuum drying is finished, filling dry nitrogen into the oven until the air pressure is 60kpa, and carrying out air circulation in the oven at 95 ℃ for 15min, wherein the air in the oven is not exchanged with the outside in the process, and repeating the vacuum drying (3) and the nitrogen drying (4) for 8 times after carrying out air circulation for 15 min; (5) pressure maintaining and warehouse-out: and after 8 times of baking circulation, the oven is vacuumized to 50Pa and maintained for 3min, then nitrogen is filled to 101kpa and maintained for 3min, a Karl Fischer moisture tester is used for moisture test to be less than 220ppm (test condition: temperature: 170 ℃ C.; test time: 200s; relative drift value: 15ug/min; gas flow: 50mL/min; sampling quality is between 0.200g and 0.300 g), and then the battery cell is discharged out of the oven.
S4: welding the positive electrode cover plate 11: for baking the ok cell, the closing, pre-spot welding and peripheral welding of the anode cover plate 11 are completed in a drying workshop (the dew point is less than or equal to-40 ℃ and the temperature is 25+/-3 ℃) within 20 minutes.
S5: testing the helium and the resistance value: after the peripheral welding of the anode cover plate 11 is finished, the battery core also needs to finish helium detection in a drying workshop (dew point is less than or equal to minus 40 ℃ and temperature is 25+/-3 ℃) within 20 minutes, the helium used in the helium detection needs to use drying gas, and the test leakage rate is less than 1.0x10 < -6 > Pa x m 3 S, and the hipot (test mode: free discharge, test time 200ms, voltage 300V, VD1:10%, VD 3:20%).
S6: the first injection and the subsequent circulation.
The results of the moisture detection are shown in FIG. 6.
Example III
The embodiment is a large-cylinder lithium ion assembly drying method which is carried out by adopting an IFR32135-15Ah lithium iron phosphate cylindrical cell and a high-temperature baking mode. Compared with the embodiment, the cycle times, baking time and the like of the embodiment are different, and the method comprises the following steps:
s1: shaping a cover plate: after the bare cell is put into the aluminum shell, the anode and cathode current collecting plates are welded respectively, and after the current collecting plates are welded, the anode and cathode cover plate 12 is subjected to three-stage shaping of pre-bending, 90-degree bending and pre-closing through the equipment shaping mechanism, so that the alignment degree of the cover plate and the center shaft of the aluminum shell is kept within +/-1 mm.
S2: welding the cathode cover plate 12: the negative electrode cover plate 12 is jacked to be covered, and is fixed by pre-spot welding at three points, so that the negative electrode cover plate 12 is prevented from being detached, peripheral welding is not performed temporarily, meanwhile, the end face of the positive electrode cover plate 11 is required to be arranged in a clearance mode, the situation that the negative electrode cover plate 12 is interfered by forced extrusion to be welded is avoided, and the positive electrode cover plate 11 still keeps a pre-covered state.
S3: the tray 2 is baked, and the baking process steps are as follows: (1) group tray 2 feed: after the peripheral welding of the negative electrode cover plate 12 is finished, the state of the battery 1 is adjusted to the state that the positive electrode cover plate 11 faces upwards, and 512ea batteries 1 form a tray and enter an oven; (2) preheating the battery cell: after the oven is closed, the baking temperature is set at 95 ℃ and is directly heated for 80 minutes, after the set time is reached, the air in the oven is pumped out to 100pa, nitrogen is filled to 80kpa, and the preheating and the heating are repeated for 80 minutes for one time, so that the temperature of the battery cell is increased by 95 ℃; (3) vacuum drying: vacuumizing the air in the box body to 100Pa after preheating is finished, and continuously baking for 60min at 95 ℃; (4) drying with nitrogen: after the vacuum drying is finished, filling dry nitrogen into the oven until the air pressure is 60kpa, and carrying out air circulation in the oven at 95 ℃ for 20min, wherein the air in the oven is not exchanged with the outside in the process, and repeating the steps of (3) vacuum drying and (4) nitrogen drying for 5 times after carrying out air circulation for 20min; (5) pressure maintaining and warehouse-out: after 5 times of baking circulation, the oven is vacuumized to 50Pa and maintained for 3min, then nitrogen is filled to 101kpa and maintained for 3min, a Karl Fischer moisture tester is used for moisture test to be less than 220ppm (test condition: temperature: 170 ℃ C.; test time: 200s; relative drift value: 15ug/min; gas flow: 50mL/min; sampling quality is between 0.200g and 0.300 g), and then the battery cell is discharged out of the oven.
S4: welding the positive electrode cover plate 11: for baking the ok cell, the closing, pre-spot welding and peripheral welding of the anode cover plate 11 are completed in a drying workshop (the dew point is less than or equal to-40 ℃ and the temperature is 25+/-3 ℃) within 20 minutes.
S5: testing the helium and the resistance value: after the peripheral welding of the anode cover plate 11 is finished, the battery core also needs to finish helium detection in a drying workshop (dew point is less than or equal to minus 40 ℃ and temperature is 25+/-3 ℃) within 20 minutes, the helium used in the helium detection needs to use drying gas, and the test leakage rate is less than 1.0x10 < -6 > Pa x m 3 S, and testing a hipot (test mode: free discharge, test time 200ms, voltage 300V, VD1:10%, VD 3)：20％)。
S6: the first injection and the subsequent circulation.
The results of the moisture detection are shown in FIG. 6.
Comparative example one
The present embodiment is a comparative example, and the IFR32135-15Ah lithium iron phosphate cylindrical battery cell is tested in a conventional manner by a high temperature baking method, and is different from the second embodiment and the third embodiment in that the positive and negative electrode cover plates 12 are both covered, and the method includes the following steps:
s1: shaping a cover plate: after the bare cell is put into the aluminum shell, the anode and cathode current collecting plates are welded respectively, and after the current collecting plates are welded, the anode and cathode cover plate 12 is subjected to three-stage shaping of pre-bending, 90-degree bending and pre-closing through the equipment shaping mechanism, so that the alignment degree of the cover plate and the center shaft of the aluminum shell is kept within +/-1 mm.
S2: and (3) welding a cover plate: the positive and negative electrode cover plates 12 are pressed and covered, fixed by pre-spot welding at three points, and then the peripheral welding is completed to complete the whole circle of sealing welding of the positive and negative electrode cover plates 12, and a hipot is tested (test mode: free discharge, test time: 200ms, voltage 300V, VD1:10% and VD 3:20%).
S3: pre-helium test: after the peripheral welding of the anode cover plate 11 is finished, the battery core also needs to finish helium detection in a drying workshop (dew point is less than or equal to minus 40 ℃ and temperature is 25+/-3 ℃) in 2H, and the test leakage rate is less than 1.0x10 < -6 > Pa x m 3 /s。
S4: the tray 2 is baked, and the baking process steps are as follows: (1) group tray 2 feed: after the peripheral welding of the anode and the cathode is completed, the state of the battery 1 is adjusted to be that the anode cover plate 11 faces upwards, and 512ea batteries 1 form a tray and enter an oven; (2) preheating the battery cell: after the oven is closed, air in the oven is pumped out to a vacuum degree of 100pa, then nitrogen is filled to 80kpa, the baking temperature is set to 95 ℃ for directly heating for 80min, after the set time is reached, the oven is vacuumized again to 100pa, nitrogen is filled again to 80kpa, preheating and heating are repeated for 80min once, and the temperature of the battery cell is increased to 95 ℃; (3) vacuum drying: vacuumizing the air in the box body to 100Pa after preheating is finished, and continuously baking for 45min at 95 ℃; (4) drying with nitrogen: after the vacuum drying is finished, filling dry nitrogen into the oven until the air pressure is 60kpa, and carrying out air circulation in the oven at 95 ℃ for 15min, wherein the air in the oven is not exchanged with the outside in the process, and repeating the vacuum drying (3) and the nitrogen drying (4) for 8 times after carrying out air circulation for 15 min; (5) cooling and leaving the warehouse: the baking circulation is carried out for 8 times, the baking oven is vacuumized to 50pa and maintained for 3min, then nitrogen is filled to 101kpa, so that the battery cell is cooled to 60 ℃, (6) moisture test is carried out by using a Karl Fischer moisture tester for less than 220ppm (test condition: temperature: 170 ℃ C.; test time: 200s; relative drift value: 15ug/min; gas flow: 50mL/min; sampling quality: 0.200 g-0.300 g), and the battery cell is discharged out of the baking oven and is tested for hipot (test mode: free discharge, test time: 200ms, voltage 300V, VD1:10%, VD 3:20%).
S6: the moisture and hipot test OK cell performs the first injection and the subsequent circulation.
As shown in fig. 6, the battery cell is dried in an open state, so that the discharge of moisture in the baking process and the nitrogen flow in the oven during the nitrogen air circulation are convenient to directly contact the battery cell electrode group, and compared with the original battery cell in the comparative example one, the battery cell is more convenient to exchange with external gas only through the liquid injection hole with the diameter of 2mm, and therefore, lower water content is obtained in a shorter time; the production efficiency is improved, the energy consumption is reduced, and the cost is saved.
It will be evident to those skilled in the art that the application is not limited to the details of the foregoing illustrative embodiments, and that the present application may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the application being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.
The above-described embodiments merely represent embodiments of the application, the scope of the application is not limited to the above-described embodiments, and it is obvious to those skilled in the art that several variations and modifications can be made without departing from the spirit of the application, which are all within the scope of the application.
Claims (10)
1. A lithium ion cylindrical battery assembling and open drying method is characterized in that: the method comprises the following steps:
s1, shaping positive and negative cover plates of a battery (1);
s2, welding a negative electrode cover plate (12) of the battery (1), and opening a positive electrode cover plate (11);
s3, drying the battery (1) in the step S2;
s4, taking out the dried battery (1) in the step S3, and welding the positive electrode cover plate (11).
2. The lithium ion cylindrical battery assembly and open drying method according to claim 1, wherein: the drying method further comprises the following steps:
s5, primary helium detection and resistance test: after the peripheral welding of the positive electrode cover plate (11) is completed, helium test and hipot test are carried out.
3. The lithium ion cylindrical battery assembly and open drying method according to claim 1, wherein: the shaping step of the step S1 includes: and (3) carrying out three-stage shaping on the anode cover plate (12) of the battery (1) after welding the current collecting disc, so that the alignment degree of the cover plate and the central shaft of the aluminum shell is kept to be +/-1 mm.
4. The lithium ion cylindrical battery assembly and open drying method according to claim 1, wherein: the welding step of the step S2 includes: the negative electrode cover plate (12) is subjected to cover closing, pre-spot welding and peripheral welding, and meanwhile, the positive electrode cover plate (11) is subjected to cover pre-closing without welding.
5. The lithium ion cylindrical battery assembly and open drying method according to claim 1, wherein: the drying step of the step S3 includes:
s31, feeding the tray (2), wherein the opening of the anode cover plate (11) is upward, and the tray (2) enters an oven;
s32, preheating the battery cell, wherein the battery cell is preheated to 80-100 ℃ in a normal air atmosphere, and the preheating time is 80-120 min;
s33, vacuum drying, vacuumizing to 50-200 pa, and baking for 30-120min;
s34, drying by nitrogen, then charging 60-80 kpa of nitrogen, carrying out wind circulation for 10-20 min, and repeating the circulation of S33 and S34 for 6-10 times;
and S35, maintaining the pressure, leaving the warehouse, vacuumizing to 50-200 Pa after baking, maintaining the pressure for 2-5min, then filling nitrogen to the atmospheric pressure, and maintaining the pressure for 2-5min to finish baking.
6. The lithium ion cylindrical battery assembly and open drying method according to claim 1, wherein: when the battery cover plates are welded, the positive and negative electrode cover plates are welded step by step, and in the first step, the negative electrode cover plates (12) are only subjected to cover closing, pre-spot welding and peripheral welding, and meanwhile, the positive electrode cover plates (11) are subjected to cover pre-closing.
7. The lithium ion cylindrical battery assembly and open drying method according to claim 1, wherein: the welding conditions of the positive electrode cover plate (11) of the battery (1) in the step S4 are as follows: and after the baking of the battery (1) is finished and the moisture test is qualified, the battery is placed in a drying workshop, the dew point in the drying workshop is less than or equal to-40 ℃, the temperature is 25+/-3 ℃, and the periphery of the positive electrode cover plate (11) of the battery (1) is welded.
8. The lithium ion cylindrical battery assembly and open drying method according to claim 1, wherein: after the welding of the positive electrode cover plate (11) is finished, dry helium is required to be used for helium detection of the battery (1), and after the helium detection is finished, the battery (1) is filled with the dry helium and is not required to be pumped out, so that the battery (1) is kept inside the battery (1) to protect the battery (1).
9. The lithium ion cylindrical battery assembly and open drying method according to claim 1, wherein: helium detection is completed within 0-30min after the welding of the positive electrode cover plate (11), the helium detection is synchronously performed in a hipot test, and the workshop conditions are as follows: the dew point is less than or equal to-40 ℃, the temperature is 25+/-3 ℃, the baking is carried out until the helium inspection is finished in a drying workshop, and the total use time is not more than 1H.
10. The lithium ion cylindrical battery assembly and open drying method according to claim 1, wherein: and after the step S3, directly taking out of the warehouse to weld the anode cover plate (11).
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