Packaging inspection method and system

Abstract

The application discloses a kind of encapsulation inspection method and system, belong to lithium ion battery manufacturing technical field, including the electrode lug fixed electric core is placed into encapsulation film and completes preliminary sealing, and preliminary sealing after encapsulation film has vacuum extraction mouth;Through vacuum extraction mouth to the encapsulation film with electric core is extracted vacuum encapsulation processing, to make encapsulation film and electric core closely adhere to, and obtain vacuum encapsulation body;Vacuum encapsulation body is stationary for a predetermined length of time;Vacuum encapsulation body is encapsulated and inspected, and determine whether vacuum encapsulation body exists appearance abnormality, when vacuum encapsulation body exists appearance abnormality, determine that encapsulation film and electric core do not meet encapsulation requirement;When vacuum encapsulation body does not exist appearance abnormality, then determine that encapsulation film and electric core meet encapsulation requirement.The application can determine whether the encapsulation effect of electric core and encapsulation film meets the requirement by using the existing electric core and encapsulation film, shorten the length of time for encapsulation inspection of electric core and encapsulation film, improve the efficiency of encapsulation inspection.

Description

Technical Field

[0001] The present invention relates to the technical field of lithium-ion battery manufacturing, and in particular to a packaging inspection method and system. Background Art

[0002] Currently, the packaging effect of soft-pack lithium-ion batteries is a key factor affecting battery performance. The manufacturing process of soft-pack lithium-ion batteries involves the tab packaging process. If the tab packaging effect is poor, the positive and negative electrodes, separator, and electrolyte inside the lithium-ion battery cannot be completely isolated from the surrounding environment. This will cause water vapor and other substances in the environment to enter the lithium-ion battery through the tabs, reacting with the electrodes and electrolyte inside the lithium-ion battery to produce gas, ultimately causing the lithium-ion battery to bulge and leak. Although obvious packaging damage can be detected before leaving the factory, smaller micropores are difficult to detect. The consequences of missed detection will pose a huge safety hazard during subsequent use. Therefore, the packaging effect needs to be inspected after the tab packaging is completed.

[0003] In the prior art, the packaging effect is mainly tested by inspecting the finished lithium-ion battery. For example, the methods of inspecting the finished lithium-ion battery include: applying greater pressure to squeeze the battery cell, causing leakage at weak seals; storing the finished lithium-ion battery in a high-temperature environment to evaporate the electrolyte and use air pressure to impact the seal, causing leakage or cracking at weak seals; placing the finished lithium-ion battery in a vacuum oven, evacuating the air so that the pressure inside the lithium-ion battery is greater than the external air pressure, thereby causing the packaging film to slightly expand, and indirectly feedback whether the packaging effect is good by measuring the expanded thickness of the packaging film with a laser.

[0004] However, the above packaging effect detection methods all require the lithium-ion battery to be assembled and formed into a finished product, and the assembly process takes a long time, resulting in a long packaging effect detection time and low efficiency. Summary of the Invention

[0005] The purpose of the present invention is to provide a packaging inspection method and system, which can use existing battery cells and packaging films to determine whether the packaging effect of the battery cells and packaging films meets the requirements, shorten the time for packaging inspection of the battery cells and packaging films, and improve the efficiency of packaging inspection.

[0006] As conceived above, the technical solution adopted by the present invention is:

[0007] A packaging inspection method comprises the following steps:

[0008] The battery cell with the tab fixed thereon is placed in a packaging film and preliminarily sealed, wherein the packaging film after preliminarily sealing has a vacuum port;

[0009] Performing a vacuum packaging process on the packaging film containing the battery cell through the vacuum port so that the packaging film and the battery cell are closely attached to each other, thereby obtaining a vacuum packaging body;

[0010] leaving the vacuum package body to stand for a preset period of time;

[0011] The vacuum package body is subjected to a packaging inspection, and it is determined whether the vacuum package body has any abnormal appearance. When the vacuum package body has any abnormal appearance, it is determined that the packaging film and the battery cell do not meet the packaging requirements; when the vacuum package body does not have any abnormal appearance, it is determined that the packaging film and the battery cell meet the packaging requirements.

[0012] Optionally, allowing the vacuum package to stand for a preset time period includes:

[0013] placing the vacuum package body into a sealed container;

[0014] The sealed container is evacuated and pressure maintained, and then filled with gas, and this cycle is repeated for a preset time or a preset number of times.

[0015] Optionally, after the sealed container is evacuated, the vacuum degree of the sealed container is -20 kPa to -100 kPa, and the pressure holding time is 5 to 120 seconds.

[0016] Optionally, after the gas is filled into the sealed container, the pressure in the sealed container is atmospheric pressure, and the pressure in the sealed container is maintained at atmospheric pressure for 5 to 120 seconds.

[0017] Optionally, determining whether the vacuum packaging body has an abnormal appearance includes: checking whether there are bubbles between the packaging film and the battery cell, checking whether the packaging film or the vacuum packaging body is deformed, and / or checking whether the hardness of the vacuum packaging body is lower than a preset hardness.

[0018] Optionally, the packaging inspection method further includes:

[0019] The vacuum packaging body is bent and a curvature of the vacuum packaging body after being bent is determined. When the curvature of the vacuum packaging body after being bent is greater than a preset curvature value, it is determined that the packaging film and the battery cell do not meet the packaging requirements; when the curvature of the vacuum packaging body after being bent is less than or equal to the preset curvature value, it is determined that the packaging film and the battery cell meet the packaging requirements.

[0020] Optionally, the following steps are also included:

[0021] Select the pole pieces and assemble them into bare cells;

[0022] The tabs are welded or bonded to the bare battery core to form a battery core.

[0023] Optionally, the preliminary sealing includes:

[0024] performing top sealing on the packaging film;

[0025] The packaging film after top sealing is side sealed.

[0026] Optionally, when the packaging film containing the battery cell is vacuum packaged through the vacuum port, the packaging parameters during the packaging process include: packaging temperature of 170-220° C., packaging pressure of 0.2-0.55 MPa, and packaging time of 2-5 seconds.

[0027] A packaging inspection system, comprising:

[0028] A packaging device is used to place the battery cell with the tab fixed thereon into a packaging film and complete preliminary sealing, wherein the packaging film after preliminary sealing has a vacuum port;

[0029] A vacuum device, used for performing a vacuum packaging process on the packaging film containing the battery cell through the vacuum port, so that the packaging film and the battery cell are closely attached to each other and a vacuum package is obtained;

[0030] The packaging inspection module is used to perform packaging inspection on the vacuum packaging body and determine whether the vacuum packaging body has any appearance abnormality. When the vacuum packaging body has any appearance abnormality, it is determined that the packaging film and the battery cell do not meet the packaging requirements; when the vacuum packaging body does not have any appearance abnormality, it is determined that the packaging film and the battery cell meet the packaging requirements.

[0031] The present invention has at least the following beneficial effects:

[0032] The packaging inspection method and system provided by the present invention first assemble the battery cell and the packaging film and complete the preliminary sealing, then perform a vacuum packaging process on the packaging film through the vacuum port on the packaging film, so that the packaging film and the battery cell are tightly fitted to obtain a vacuum packaging body, and after the vacuum packaging body is left to stand for a preset period of time, the vacuum packaging body is inspected to determine whether the packaging between the packaging film and the battery cell meets the requirements. There is no need to prepare finished lithium-ion batteries. Using the existing battery cell and packaging film, it is possible to determine whether the packaging effect of the battery cell and the packaging film meets the requirements and whether there are defects, thereby shortening the time for packaging inspection of the battery cell and the packaging film and improving the efficiency of packaging inspection. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 This is a flow chart of a packaging inspection method provided by an embodiment of the present invention;

[0034] Figure 2 is a flow chart of another packaging inspection method provided by an embodiment of the present invention;

[0035] Figure 3 It is a schematic diagram of the assembly of the battery cell and the packaging film provided in an embodiment of the present invention.

[0036] In the picture:

[0037] 1. Bare cell; 2. Tab; 3. Packaging film; 41. Top seal; 42. Side seal. DETAILED DESCRIPTION

[0038] To make the technical problems solved by the present invention, the technical solutions adopted, and the technical effects achieved more clearly, the technical solutions of the present invention are further described below with reference to the accompanying drawings and through specific embodiments. It should be understood that the specific embodiments described herein are merely for the purpose of explaining the present invention and are not intended to limit the present invention. It should also be noted that, for ease of description, the drawings only show portions relevant to the present invention, not all of them.

[0039] In the description of the present invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings and are intended solely to facilitate and simplify the description of the present invention. They do not indicate or imply that the devices or components referred to must have a specific orientation, be constructed, or operate in a specific orientation. Therefore, they should not be construed as limitations on the present invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0040] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood broadly. For example, they may refer to fixed or detachable connections; mechanical or electrical connections; direct or indirect connections through an intermediary; and internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention.

[0041] Example 1

[0042] This embodiment provides a packaging inspection method, which does not require inspection after the lithium-ion battery is assembled to obtain a finished product, but can be inspected after the semi-finished product is obtained, making the packaging inspection method more efficient.

[0043] First, to facilitate understanding, the specific assembly structure of the battery cell and the packaging film involved in this embodiment is briefly described.

[0044] like Figure 3As shown, the battery cell includes a bare cell 1 and two tabs 2 fixed to the bare cell 1. The two tabs 2 are fixed to opposite ends of the bare cell 1. The bare cell 1 is assembled from electrode pieces. Optionally, since the packaging inspection method provided in this embodiment does not have high requirements for the battery cell, the electrode pieces in this embodiment can be inferior or unqualified electrode pieces.

[0045] In the prior art, after the battery cell is assembled, a packaging film 33 (such as an aluminum-plastic film) needs to be arranged outside the battery cell, and the packaging film 3 is specifically arranged outside the bare battery cell 1, and the two tabs 2 are respectively passed through the packaging film 3. When assembling the packaging film 3, two film sheets are usually prepared first, and then the two film sheets are wrapped around the upper and lower sides of the battery cell. The size of the film sheet is larger than the size of the battery cell. Therefore, the edges of the two film sheets can be packaged, such as by heat sealing to combine the edges of the two film sheets together and form a packaging film 3. There is a gap between the packaging film 3 and the battery cell, and the gap is used to accommodate the electrolyte. That is, after the three edges of the packaging film 3 are sealed, an opening is reserved for filling the electrolyte into the packaging film 3. The packaging film 3 is then completely sealed to form a relatively independent structure. Since the tab 2 needs to pass through the packaging film 3 and the tab 2 usually has an irregular structure, the sealing between the packaging film 3 and the tab 2 is more complicated and more prone to packaging failure. The other packaging parts are the sealing between the diaphragms, the technology is relatively mature, and packaging failure is not prone to occur. Therefore, this embodiment mainly tests the packaging effect between the tab 2 and the packaging film 3.

[0046] like Figure 1 As shown, the packaging inspection method includes the following steps:

[0047] S10, placing the battery cell with the tab fixed thereon into a packaging film and completing preliminary sealing, wherein the packaging film after preliminary sealing has a vacuum port.

[0048] It should be noted that the battery cell with tabs fixed refers to the battery cell obtained after the tabs are fixed outside the bare battery cell. The preliminary sealing refers to the hot pressing and sealing of the bottom edge and the two side edges of the two membrane sheets to form a packaging film and wrap it around the battery cell. The two tabs pass through the top and bottom of the packaging film, and the preliminary sealing also includes the sealing between the packaging film and the tabs. During the preliminary sealing process, a vacuum port is reserved at the edge of the packaging film to facilitate the subsequent vacuum packaging of the packaging film. Optionally, the vacuum port can be the liquid injection port of the packaging film in the normal production process. The liquid injection port is used to inject electrolyte into the packaging film. That is, in this embodiment, the liquid injection port is used as the vacuum port, and there is no need to open an additional opening, thereby realizing the multi-purpose use of the liquid injection port. In addition, the technology for opening the liquid injection port is relatively mature, and the technology for subsequent sealing is also relatively mature. Therefore, the situation where the sealing effect of the liquid injection port is poor will not occur, which reduces the influence of the liquid injection port on the packaging inspection results and ensures that the object of the packaging inspection is mainly the seal between the tab and the packaging film.

[0049] Optionally, the battery cell with the tabs attached can be placed within the packaging film and initially sealed using a packaging device. To ensure the effectiveness of the initial sealing, the packaging parameters during packaging are: a packaging temperature of 170-220°C, a packaging pressure of 0.2-0.55 MPa, and a packaging time of 2-5 seconds. In some embodiments, the packaging film and battery cell can be placed in a packaging device for packaging. In this case, the aforementioned packaging parameters can be set directly within the packaging device.

[0050] Alternatively, the preliminary sealing includes top sealing the packaging film and then side sealing the top-sealed packaging film. The specific methods of top sealing and side sealing can refer to the existing technology and are not limited in this embodiment. Figure 3 As shown, after the top seal is completed, a top seal 41 will be formed, and after the side seal is completed, a side seal 42 will be formed.

[0051] In this embodiment, the packaging film may be an aluminum-plastic film, an inorganic film, etc., which is not limited in this embodiment.

[0052] S20, performing vacuum packaging processing on the packaging film containing the battery cell through the vacuum port, so that the packaging film and the battery cell are closely attached to obtain a vacuum package body.

[0053] It should be noted that a vacuum device can be used to perform vacuum packaging on the packaging film, and the vacuum degree during vacuuming can be determined according to actual needs. During the vacuuming process, the gas in the packaging film is extracted, and there is a certain vacuum degree in the packaging film. The packaging film is close to the battery cell under the pressure of the external atmospheric pressure; when the gas in the packaging film is completely extracted, the packaging film is tightly attached to the outer surface of the battery cell under the pressure of the external atmospheric pressure. Since there is no gas between the packaging film and the battery cell, the overall hardness formed by the packaging film and the battery cell is relatively large, that is, the hardness of the vacuum packaging body is relatively large. It should be noted that before placing the battery cell on the packaging film, a corresponding pit is punched out on the packaging film according to the size of the battery cell. When the battery cell is placed in the pit, the battery cell and the packaging film are basically in contact. After vacuum packaging, the packaging film and the battery cell are tightly attached.

[0054] In this embodiment, after the battery cell and the packaging film are preliminarily sealed, the packaging film is vacuum-packed without injecting electrolyte into the packaging film, which saves the step of injecting electrolyte in the manufacture of finished lithium-ion batteries in the prior art, improves the efficiency of packaging inspection, saves the cost of electrolyte, and thus reduces the cost of packaging inspection.

[0055] Optionally, after all the gas in the packaging film is extracted, that is, after the packaging film containing the battery cell is vacuum-packaged through the vacuum port, the vacuum port is packaged to form a relatively sealed vacuum package. Among them, the method of packaging the vacuum port can refer to the method of packaging the liquid injection port in the manufacturing process of lithium-ion batteries in the prior art, and this embodiment is not limited to this. For example, the packaging parameters when the vacuum port is packaged include packaging temperature, packaging pressure and packaging time. Among them, the packaging temperature is 170~220℃, the packaging pressure is 0.2~0.55MPa, and the packaging time is 2~5 seconds, so as to have a better packaging effect, thereby reducing the probability of poor sealing of the vacuum port.

[0056] S30, leaving the vacuum package body to stand for a preset time.

[0057] After obtaining the vacuum package body, the vacuum package body is allowed to stand for a preset time. If the sealing between the tab and the packaging film is unqualified, that is, there are pores between the tab and the packaging film, the gas in the air will enter the packaging film from the pores; if the sealing between the tab and the packaging film is qualified, the gas in the air will not enter the packaging film. When the pores between the tab and the packaging film are large, air can quickly enter the packaging film, and then it can be quickly found out whether the packaging between the packaging film and the battery cell meets the requirements; when the pores between the tab and the packaging film are small, it is necessary to stand for a period of time to check whether the packaging between the packaging film and the battery cell meets the requirements. The preset time can be determined according to the actual situation. If the vacuum package body is directly placed in the air, the preset time is longer to prevent the situation where the time is too short, resulting in less gas entering the packaging film and no detection of unqualified packaging. If the vacuum package body is placed in other environments, the preset time can be shorter.

[0058] S40. Perform packaging inspection on the vacuum package body and determine whether the vacuum package body has any abnormal appearance. When the vacuum package body has any abnormal appearance, determine that the packaging between the packaging film and the battery cell does not meet the packaging requirements; when the vacuum package body does not have any abnormal appearance, determine that the packaging between the packaging film and the battery cell meets the packaging requirements.

[0059] After the vacuum package has been allowed to rest for a preset period of time, a packaging inspection is performed on the vacuum package to determine whether it meets the packaging requirements. During the packaging inspection, the vacuum package is primarily inspected for any appearance abnormalities. If the vacuum package has any appearance abnormalities, it indicates that air has entered between the packaging film and the battery cell, and thus it can be determined that the packaging of the packaging film at the tab does not meet the packaging requirements. If the vacuum package has no appearance abnormalities, it indicates that air has not entered between the packaging film and the battery cell, and thus it can be determined that the packaging of the packaging film at the tab meets the packaging requirements.

[0060] In this embodiment, the vacuum package can be inspected using a packaging inspection module, which can include one or more of a camera module, a scanning module, a deformation detector, and a hardness detector. It is understood that in this embodiment, the vacuum package can also be inspected manually, that is, by touching or observing the package to determine whether it meets the packaging requirements.

[0061] Optionally, in this embodiment, determining whether there are any abnormal appearances of the vacuum packaging body includes: checking whether there are bubbles between the packaging film and the battery cell, checking whether the packaging film or the vacuum packaging body is deformed, and / or checking whether the hardness of the vacuum packaging body is lower than a preset hardness. Among them, checking whether there are bubbles between the packaging film and the battery cell can be called a bubble test, checking whether the packaging film or the vacuum packaging body is deformed can be called a deformation test, and checking whether the hardness of the vacuum packaging body is lower than a preset hardness can be called a hardness test. Bubble test refers to checking whether there are bubbles between the packaging film and the battery cell. If there are bubbles between the packaging film and the battery cell, the appearance of the vacuum packaging body has changed, and it is determined that gas has entered the packaging film, which means that there is a pore at the packaging film and the tab package. Deformation test refers to checking whether the packaging film is deformed or wrinkled. If the packaging film is deformed or wrinkled, the appearance of the vacuum packaging body has changed, and it is determined that gas has entered the packaging film, which means that there is a pore at the packaging film and the tab package. The hardness test is to check whether the hardness of the packaging film has decreased. If the hardness of the packaging film is lower than the preset hardness, it means that the packaging film has softened, and the appearance of the vacuum package has changed. This further confirms the presence of air between the packaging film and the battery cell, which means there is a gap between the packaging film and the tab. If there are no bubbles between the packaging film and the battery cell, the packaging film is not deformed or wrinkled, and the hardness of the packaging film is not lower than the preset hardness, it means that there is no gap between the packaging film and the tab, and the packaging requirements are met. The preset hardness can be the instantaneous hardness of the vacuum package obtained after the vacuum is evacuated. Optionally, the bubble test, deformation test, and hardness test can be performed simultaneously to improve the accuracy of the test.

[0062] Optionally, the packaging inspection method further includes bending the vacuum packaging body and determining the curvature of the vacuum packaging body after being bent. When the curvature of the vacuum packaging body after being bent is greater than a preset curvature value, it indicates that the vacuum packaging body has become soft, and it is further determined that the packaging film and the battery cell do not meet the packaging requirements, that is, the packaging portion of the packaging film and the tab does not meet the packaging requirements. When the curvature of the vacuum packaging body after being bent is less than or equal to the preset curvature value, it indicates that the vacuum packaging body is still very hard, and it is further determined that the packaging film and the battery cell meet the packaging requirements, that is, the packaging portion of the packaging film and the tab meets the packaging requirements.

[0063] The packaging inspection method provided in this embodiment first assembles the battery cell and the packaging film and completes the preliminary sealing, then vacuum-packs the packaging film through the vacuum port on the packaging film so that the packaging film and the battery cell are tightly fitted to obtain a vacuum package body, and after the vacuum package body is left to stand for a preset period of time, the appearance of the vacuum package body is inspected to determine whether the packaging between the packaging film and the battery cell meets the requirements. There is no need to prepare finished lithium-ion batteries. The existing battery cell and packaging film can be used to determine whether the packaging effect of the battery cell and the packaging film meets the requirements and whether there are any defects, thereby shortening the time for packaging inspection of the battery cell and the packaging film and improving the efficiency of packaging inspection.

[0064] Moreover, since the gas molecules are small, even small defects in the packaging between the packaging film and the tab can be discovered, which can reflect defects at the microscopic level, has high sensitivity, and the inspection process is relatively simple.

[0065] Because the packaging effect is related to the parameters used during packaging, if the packaging effect of the battery cell and packaging film is found to be unsatisfactory, the packaging parameters can be adjusted and another set of battery cells and packaging films can be packaged until the packaging parameter range that satisfies the packaging effect is locked in. When adjusting the packaging parameters, the packaging temperature is usually adjusted by 5°C, the packaging pressure by 0.05MPa, and the packaging time by 0.5 seconds to achieve higher sensitivity.

[0066] Optionally, in order to further improve the efficiency of packaging inspection, the vacuum package can be subjected to accelerated inspection. There are many ways to accelerate the inspection, and this embodiment provides the following exemplary accelerated inspection methods.

[0067] The accelerated inspection process includes placing the vacuum package in an alternating negative pressure and normal pressure environment. Figure 2 As shown, step S30 includes:

[0068] S31. Place the vacuum package into a sealed container.

[0069] Optionally, the sealed container can be connected to a vacuum pump, so that the vacuum pump can evacuate the sealed container. A bracket can be provided in the sealed container, the top surface of the bracket being composed of a plurality of crossbeams, and the vacuum packaging body is placed on the crossbeams. When the sealed container is evacuated, most of the vacuum packaging body can be exposed to the outside, thereby facilitating the inspection of packaging defects at different locations of the packaging film.

[0070] S32, evacuating the sealed container and maintaining the pressure for a first period of time.

[0071] In this embodiment, a vacuum pump is used to evacuate the sealed container, so that the pressure in the sealed container is negative. For example, after evacuating the sealed container, the vacuum level is -20kPa to -100kPa, and the pressure is maintained for 5 to 120 seconds. In other words, the first duration is 5 to 120 seconds. Preferably, the first duration is 5 seconds to improve the efficiency of packaging inspection.

[0072] S33: Fill the sealed container with gas and maintain the gas for a second period of time.

[0073] After the pressure is maintained for the first time period, gas is filled into the sealed container so that the pressure in the sealed container gradually increases. Optionally, in this embodiment, after the sealed container is filled with gas, the pressure in the sealed container is atmospheric pressure, that is, the pressure in the sealed container is normal pressure. Moreover, when the pressure in the sealed container reaches normal pressure, the pressure of the sealed container is controlled to maintain atmospheric pressure for 5 to 120 seconds, that is, the second time period is 5 to 120 seconds. In some embodiments, the method of inflating the sealed container with gas can be to disconnect the connection between the vacuum pump and the sealed container, so that under the action of the pressure difference, the outside air is filled into the sealed container through negative pressure. Optionally, the second time period is equal to the first time period.

[0074] S34, looping through steps S32 and S33 until the preset duration or the preset number of loops is reached.

[0075] If there are defects in the seal between the battery cell and the packaging film, the vacuum package will be repeatedly cycled between negative pressure and normal pressure. External gas will enter the packaging film through the pores, causing the battery cell and the packaging film to lose their tight fit and rapidly deform. The hardness of the vacuum package will be significantly softened, making it easier to subsequently determine whether the vacuum package meets the packaging requirements. The preset duration and the preset number of times can be determined based on actual needs. Optionally, the preset number of times is greater than or equal to 2, and preferably, the preset number of times is 5.

[0076] The vacuum packaging system cycles between negative and normal pressure, allowing defects in the seal between the cell and the film to be revealed quickly, facilitating rapid leak detection. After numerous field tests, defects in the seal between the cell and the film can be detected in approximately ten minutes.

[0077] Optionally, before step S10, the packaging inspection method further includes the following steps:

[0078] S1. Select the electrodes and assemble them into a bare cell.

[0079] In step S1 , inferior or defective electrodes can be selected to be assembled into bare cells. That is, the packaging inspection method provided in this embodiment has lower requirements for cells, thereby reducing the cost of packaging inspection.

[0080] S2, welding or bonding the tab on the bare battery cell, and forming the battery cell.

[0081] In this embodiment, the tab can be directly welded on the bare battery cell, or the tab can also be bonded on the bare battery cell by using adhesive tape, etc., which is not limited in this embodiment.

[0082] For example, the embodiment provides the following three specific packaging inspection methods.

[0083] In one specific packaging inspection method, a bare battery cell assembled with inferior or defective tabs is taken, the tab is welded, and is placed in an aluminum-plastic film (i.e. packaging film) punched to fix it, the top sealing temperature is set to 175℃, the top sealing pressure is set to 0.3MPa, and the top sealing time is set to 2.5S to perform top sealing. Moreover, the side sealing temperature is set to 185℃, the side sealing pressure is set to 0.4MPa, and the side sealing time is set to 3.0S to perform side sealing. The battery cell after top sealing and side sealing is not injected with liquid, and is directly subjected to vacuum packaging treatment through a vacuum extraction port, after which the vacuum extraction port is subjected to packaging treatment, which is also called pre-sealing. Specifically, the pre-sealing temperature is set to 190℃, the pre-sealing pressure is set to 0.4MPa, and the pre-sealing time is set to 3.0S to obtain a vacuum packaging body. The pre-sealed battery cell is placed in a vacuum oven, and the vacuum oven program is set to vacuum extraction to -40kpa, maintaining for 10S, pressure relief to normal pressure, maintaining for 10S, and repeating for 5 times. After the cycle is completed, the vacuum packaging body is taken out, and whether there is a wrinkle or deformation on the appearance of the vacuum packaging body is observed, and the vacuum packaging body is slightly bent. The state of the vacuum packaging body before and after being placed in the vacuum oven is compared. If there is obvious wrinkle or deformation on the surface of the battery cell, or the vacuum packaging body is obviously softened, it indicates that there is a gas leakage hidden danger in the packaging, and the top sealing packaging effect is poor. The top sealing packaging parameters are adjusted, the adjusted top sealing temperature is set to 180℃, the top sealing pressure is set to 0.3MPa, and the top sealing time is set to 2.5S. After the packaging parameters are adjusted, the above test is repeated until the packaging effect meets the requirements.

[0084] In another specific packaging inspection method, a bare cell assembled with inferior or defective pole pieces is taken, the pole ears are fixed with tape, and the cell is placed in an aluminum-plastic film with a hole punched therein and fixed in position. The packaging parameters are set, the top sealing temperature is 170°C, the top sealing pressure is 0.3MPa, the top sealing time is 2.5S, the side sealing temperature is 190°C, the side sealing pressure is 0.4MPa, and the side sealing time is 3.0S to perform top sealing and side sealing. The cell after top sealing and side sealing is not injected with liquid, but is directly vacuum packaged through the vacuum port. After that, the vacuum port is packaged. This packaging process is also called pre-sealing. Specifically, the pre-sealing temperature is 190°C, the pre-sealing pressure is 0.3Mpa, and the pre-sealing time is 3.0S to obtain Vacuum package body; put the pre-sealed vacuum package body into a vacuum oven, set the vacuum oven program to evacuate to -50kpa, maintain for 5S, release the pressure to normal pressure, maintain for 5S, and cycle 10 times; after the cycle, take out the vacuum package body, observe whether there are wrinkles or deformations on the surface of the vacuum package body, and bend the vacuum package body with slight force, and compare the state of the vacuum package body before and after entering the vacuum oven. If there are obvious wrinkles or deformations on the surface of the vacuum package body or the vacuum package body is obviously softened, it means that there is a risk of air leakage in the seal and the top seal packaging effect is poor. Adjust the top seal packaging parameters, the top seal temperature is 170℃, the top seal pressure is 0.35MPa, and the top seal time is 2.5S; after the packaging parameters are adjusted, repeat the above test until the packaging effect meets the requirements.

[0085] In another specific packaging inspection method, a bare battery cell assembled with inferior or defective pole pieces is taken, the pole ears are welded, and the cell is placed in a punched aluminum-plastic film and fixed in position. The packaging parameters are set, the top sealing temperature is 175°C, the top sealing pressure is 0.3MPa, the top sealing time is 2.5S, the side sealing temperature is 185°C, the side sealing pressure is 0.4MPa, and the side sealing time is 3.0S to perform top sealing and side sealing. The battery cell after top sealing and side sealing is not injected with liquid, but is directly vacuum packaged through the vacuum port. After that, the vacuum port is packaged. This packaging process is also called pre-sealing. Specifically, the pre-sealing temperature is 190°C, the pre-sealing pressure is 0.4Mpa, and the pre-sealing time is 3.0S. to the vacuum package body; put the pre-sealed vacuum package body into a vacuum oven, set the vacuum oven program to evacuate to -60kpa, maintain 8S, release the pressure to normal pressure, maintain 8S, and cycle 8 times; after the end, take out the vacuum package body, observe whether there are wrinkles or deformations on the surface of the vacuum package body, and bend the vacuum package body with slight force, and compare the state of the vacuum package body before and after entering the vacuum oven. If there are obvious wrinkles or deformations on the surface of the vacuum package body or the vacuum package body is obviously softened, it means that there is a risk of air leakage in the seal and the top seal packaging effect is poor. Adjust the top seal packaging parameters, the top seal temperature is 175℃, the top seal pressure is 0.3MPa, and the top seal time is 3.0S; after the packaging parameters are adjusted, repeat the above test until the packaging effect meets the requirements.

[0086] The packaging inspection method provided in this embodiment is highly convenient and rapid. It eliminates the need for specialized finished product preparation and utilizes existing lithium battery equipment to quickly determine whether packaging defects exist. Combined with packaging parameter adjustments, it can quickly identify a packaging parameter range that satisfies the desired packaging effect. While this embodiment is primarily used to detect top seal defects, it can also be used to detect other packaging defects.

[0087] Example 2

[0088] This embodiment provides a packaging inspection system for implementing the packaging inspection method described in Implementation 1. The packaging inspection system includes a packaging device, a vacuum pumping device, and a packaging inspection module.

[0089] The packaging device is used to place the battery cell with the tab fixed thereto into the packaging film and complete the preliminary sealing. The packaging film after the preliminary sealing has a vacuum port. The vacuum device is used to vacuum the packaging film containing the battery cell through the vacuum port to ensure that the packaging film and the battery cell are tightly fitted and a vacuum package is obtained. The packaging inspection module is used to perform packaging inspection on the vacuum package to determine whether the vacuum package has any appearance abnormalities. If the vacuum package has any appearance abnormalities, it is determined that the packaging film and the battery cell do not meet the packaging requirements. If the vacuum package does not have any appearance abnormalities, it is determined that the packaging film and the battery cell meet the packaging requirements.

[0090] Optionally, the packaging inspection system further includes a sealed container.

[0091] The packaging inspection system provided in this embodiment has the same beneficial effects as the packaging inspection method in the first embodiment, and this embodiment will not be described in detail here.

[0092] The above embodiments merely illustrate the basic principles and features of the present invention. The present invention is not limited to the above embodiments. Various changes and modifications may be made to the present invention without departing from the spirit and scope of the present invention. Such changes and modifications are intended to fall within the scope of the present invention. The scope of protection claimed in the present invention is defined by the appended claims and their equivalents.

Claims

1. A packaging inspection method, characterized in that: The steps include: The battery cell with the tab fixed thereon is placed in a packaging film and preliminarily sealed, wherein the packaging film after preliminarily sealing has a vacuum port; Performing a vacuum packaging process on the packaging film containing the battery cell through the vacuum port so that the packaging film and the battery cell are closely attached to each other, thereby obtaining a vacuum packaging body; leaving the vacuum package body to stand for a preset period of time; Performing a packaging inspection on the vacuum package body and determining whether the vacuum package body has an appearance abnormality, and when the vacuum package body has an appearance abnormality, determining that the packaging film and the battery cell do not meet the packaging requirements; and when the vacuum package body does not have an appearance abnormality, determining that the packaging film and the battery cell meet the packaging requirements; The packaging inspection method further includes: The vacuum packaging body is bent and a curvature of the vacuum packaging body after being bent is determined. When the curvature of the vacuum packaging body after being bent is greater than a preset curvature value, it is determined that the packaging film and the battery cell do not meet the packaging requirements; when the curvature of the vacuum packaging body after being bent is less than or equal to the preset curvature value, it is determined that the packaging film and the battery cell meet the packaging requirements.

2. The packaging inspection method according to claim 1, characterized in that: The vacuum package is left to stand for a preset period of time, comprising: placing the vacuum package body into a sealed container; The sealed container is evacuated and pressure maintained, and then filled with gas, and this cycle is repeated for a preset time or a preset number of times.

3. The packaging inspection method according to claim 2, characterized in that: After the sealed container is evacuated, the vacuum degree of the sealed container is -20kPa~-100kPa, and the pressure holding time is 5~120 seconds.

4. The packaging inspection method according to claim 2, characterized in that: After the gas is filled into the sealed container, the pressure in the sealed container is atmospheric pressure, and the pressure in the sealed container is maintained at atmospheric pressure for 5 to 120 seconds.

5. The packaging inspection method according to claim 1, characterized in that: Determining whether the vacuum packaging body has an appearance abnormality includes: checking whether there are bubbles between the packaging film and the battery cell, checking whether the packaging film or the vacuum packaging body is deformed, and / or checking whether the hardness of the vacuum packaging body is lower than a preset hardness.

6. The packaging inspection method according to any one of claims 1 to 5, characterized in that: The following steps are also included: Select the pole pieces and assemble them into bare cells; The tabs are welded or bonded to the bare battery core to form a battery core.

7. The packaging inspection method according to any one of claims 1 to 5, characterized in that: The preliminary sealing includes: performing top sealing on the packaging film; The packaging film after top sealing is side sealed.

8. The packaging inspection method according to any one of claims 1 to 5, characterized in that: When the packaging film containing the battery cell is vacuum packaged through the vacuum port, the packaging parameters during the packaging process include: packaging temperature of 170~220°C, packaging pressure of 0.2~0.55MPa, and packaging time of 2~5 seconds.

9. A packaging inspection system, applied to the packaging inspection method according to any one of claims 1 to 8, characterized in that: include: A packaging device is used to place the battery cell with the tab fixed thereon into a packaging film and complete preliminary sealing, wherein the packaging film after preliminary sealing has a vacuum port; A vacuum device, used for performing a vacuum packaging process on the packaging film containing the battery cell through the vacuum port, so that the packaging film and the battery cell are closely attached to each other and a vacuum package is obtained; The packaging inspection module is used to perform packaging inspection on the vacuum packaging body and determine whether the vacuum packaging body has any appearance abnormality. When the vacuum packaging body has any appearance abnormality, it is determined that the packaging film and the battery cell do not meet the packaging requirements; when the vacuum packaging body does not have any appearance abnormality, it is determined that the packaging film and the battery cell meet the packaging requirements.

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