Device, system and method for testing airtightness of battery cell

Abstract

Disclosed in the present application are a device, system and method for testing the airtightness of a battery cell. The device for testing the airtightness of a battery cell comprises a compartment and a cover, wherein the cover is disposed on the compartment in a covering manner, and the cover and the compartment form a cavity for accommodating a battery cell; a vacuum tube and a gas injection tube are provided on the cover; the vacuum tube is in communication with the cavity, and the vacuum tube is configured to be tapped to a gas detector; the gas injection tube is provided with a gas injection channel and a vacuum channel, the gas injection channel being configured to correspond to a liquid injection hole, and the vacuum channel being configured to correspond to the peripheral side of the liquid injection hole; and an end portion of the gas injection tube is in contact with the peripheral side of the liquid injection hole of the battery cell and is in communication with the liquid injection hole of the battery cell. The present application can reduce the risk of plastic deformation of an ultra-thin casing during airtightness testing of the battery cell.

Description

Battery cell airtightness detection device, system and method

[0001] Cross-reference to related applications

[0002] This application claims priority to Chinese Patent Application 202410526915.X, filed on April 29, 2024, entitled “Battery cell airtightness detection device, system and method,” the entire contents of which are incorporated herein by reference. TECHNICAL FIELD

[0003] The present application relates to the technical field of batteries, in particular to a battery cell airtightness detection device, system and method. BACKGROUND

[0004] In recent years, with the rapid development of new energy technology, new energy vehicles are being used more and more widely, and are gradually replacing traditional fuel vehicles to become one of the mainstream transportation tools. As the power source of new energy vehicles, power batteries are one of the core equipment of new energy vehicles.

[0005] Battery cells need to be tested for airtightness before use, but how to improve the reliability of airtightness detection of ultra-thin shell battery cells has become a problem to be solved. SUMMARY

[0006] The present application provides a battery cell airtightness detection device, system and method, which can improve the reliability of airtightness detection of ultra-thin shell battery cells.

[0007] In a first aspect, the present application provides a battery cell airtightness detection device, comprising a warehouse body and a cover body, the cover body is arranged on the warehouse body, and the cover body and the warehouse body form a cavity for accommodating a battery cell; a vacuum pipeline and a gas injection pipeline are arranged on the cover body, the vacuum pipeline is in communication with the cavity, and the end of the gas injection pipeline is in contact with the circumferential side of the liquid injection hole of the battery cell and is in communication with the liquid injection hole of the battery cell; the vacuum pipeline is used for tapping to a gas detector; the gas injection pipeline is provided with a gas injection channel and a vacuum channel, the gas injection channel is used for corresponding to the liquid injection hole, and the vacuum channel is used for corresponding to the circumferential side of the liquid injection hole.

[0008] In the above scheme, when testing the air tightness of the battery monomer, first, the battery monomer is placed on the bin body, then the cover body is covered on the bin body, then the cavity is vacuumed through the vacuum pipeline, and then the gas is injected into the inside of the battery monomer through the gas injection pipeline to detect the air tightness. After the battery monomer is injected with gas under positive pressure, if the battery monomer has a leak, the tracer gas in the battery monomer leaks to the bin body and is branched to the external gas detector (such as a mass spectrometer) through the bin body vacuum pipeline. The mass spectrometer quantitatively analyzes the amount of tracer gas leaked from the battery monomer, and determines whether the battery monomer is a defective product according to the preset specification. When the battery monomer has a leak rate greater than the specification value, it is a defective product, otherwise it is a good product. The inside of the battery monomer is under positive pressure relative to the outside, which reduces the risk of plastic deformation of the ultra-thin shell during air tightness testing of the battery monomer. The shell part around the liquid injection hole of the battery monomer can be vacuumed through the vacuum channel of the gas injection pipeline, thereby further reducing the risk of plastic deformation of the ultra-thin shell during air tightness testing of the battery monomer.

[0009] In some embodiments, the gas injection pipeline includes a gas injection manifold, a gas injection connecting pipe, and a plurality of gas injection branch pipes. The gas injection connecting pipe is connected to the gas injection manifold. The plurality of gas injection branch pipes are respectively connected to the gas injection connecting pipe, and are respectively used to communicate with the plurality of liquid injection holes one by one.

[0010] In the above scheme, the plurality of gas injection branch pipes are sequentially connected through the gas injection connecting pipe and collectively connected to the gas injection manifold, so that the air tightness of the plurality of battery monomers can be detected at the same time.

[0011] In some embodiments, a part of the gas injection pipeline in contact with the periphery of the liquid injection hole is provided with a vacuum suction cup, and the vacuum suction cup is in communication with the vacuum channel.

[0012] In the above scheme, by providing a vacuum suction cup at the end of the vacuum channel, the contact area of the gas injection pipeline with the shell part around the liquid injection hole can be increased, thereby improving the vacuum suction force of the gas injection pipeline on the battery monomer.

[0013] In some embodiments, the plurality of vacuum channels are arranged in a ring around the periphery of the gas injection channel.

[0014] In the above scheme, by respectively providing a vacuum channel on the periphery of the gas injection channel, the vacuum suction force and uniformity of the vacuum suction force of the gas injection pipeline on the battery monomer can be improved.

[0015] In some embodiments, the vacuum pipeline includes a vacuum manifold, a vacuum connecting pipe, and a plurality of vacuum branch pipes. The vacuum connecting pipe is connected to the vacuum manifold. The plurality of vacuum branch pipes are respectively connected to the vacuum connecting pipe, and are respectively used to communicate with the cavity.

[0016] In the scheme, the multiple vacuum branch pipes are connected in sequence through the vacuum connection pipe and connected with the vacuum collection pipe, so that the contact area of the vacuum pipeline with the cover body is increased, thereby improving the efficiency of the vacuum pipeline in vacuumizing the cavity.

[0017] In some embodiments, a plurality of accommodating grooves are arranged in the bin body, and the plurality of accommodating grooves are arranged at intervals, and each accommodating groove is used to accommodate one battery monomer.

[0018] In the scheme, the plurality of battery monomers are fixed one by one through the plurality of accommodating grooves, so that the stability of each battery monomer during the air tightness detection can be improved.

[0019] In some embodiments, the accommodating groove comprises a first side and a second side, the second side is connected with the first side, the length of the second side is greater than the length of the first side, and the second side is provided with a reinforcing portion extending towards the cover body.

[0020] In the scheme, the reinforcing portion is arranged on the second side with relatively long length, so that the exposed part of the side with relatively large area of the battery monomer relative to the accommodating groove can be protected, and the indentation of the side with relatively large area of the battery monomer during the air tightness detection can be prevented to a certain extent.

[0021] In a second aspect, the embodiments of the present application also provide a system for detecting the air tightness of a battery monomer, which comprises the air tightness detection device of any of the above-mentioned embodiments.

[0022] In a third aspect, the embodiments of the present application also provide a method for detecting the air tightness of a battery monomer, which adopts the air tightness detection device of any of the above-mentioned embodiments, and the method comprises the following steps:

[0023] Placing the battery monomer in the bin body;

[0024] Covering the bin body with the cover body;

[0025] Vacuumizing the cavity through the vacuum pipeline;

[0026] Injecting gas into the interior of the battery monomer through the gas injection pipeline;

[0027] Detecting whether there is gas leakage in the interior of the battery monomer through the gas detector.

[0028] In the scheme, the interior of the battery monomer forms a positive pressure relative to the exterior, so that the risk of plastic deformation of the ultra-thin shell during the air tightness detection of the battery monomer is reduced.

[0029] In some embodiments, the step of vacuumizing the cavity through the vacuum pipeline comprises:

[0030] Vacuumizing the vacuum passage of the gas injection pipeline, so that the battery monomer is adsorbed by the gas injection pipeline along the circumferential side of the liquid injection hole.

[0031] In the above scheme, the shell part around the liquid injection hole of the battery monomer can be vacuum adsorbed through the vacuum channel of the gas injection pipeline, thereby further reducing the risk of plastic deformation of the ultra-thin shell during the air tightness detection of the battery monomer.

[0032] In some embodiments, the absolute pressure of the vacuum adsorption of the gas injection pipeline to the battery monomer is P1, and P1 satisfies the following condition: 20Pa≤P1≤20000Pa, which neither exceeds the limit vacuum degree of the gas injection pipeline, nor ensures the adsorption force of the gas injection pipeline to the battery monomer to a certain extent.

[0033] In some embodiments, P1 satisfies the following condition: 20Pa≤P1≤200Pa, which further reduces the difficulty of the vacuum degree requirement when the vacuum equipment is vacuumized.

[0034] In some embodiments, the vacuum absolute pressure of the vacuum pipeline is P2, and P2 satisfies the following condition: 0Pa<P2≤40Pa, which can be applied to the foolproof detection of whether the pressure sensor is damaged or the pipeline is blocked, and can also reduce the leakage of gas in the cavity to the inside of the battery monomer, thereby affecting the air tightness detection.

[0035] In some embodiments, P2 satisfies the following condition: 5Pa≤P2≤40Pa, which further facilitates the foolproof detection of whether the pressure sensor is damaged or the pipeline is blocked.

[0036] In some embodiments, the injection pressure of the gas injection pipeline into the inside of the battery monomer is P3, and P3 satisfies the following condition: 50Pa≤P3≤300Pa, which can reduce the risk of plastic deformation of the ultra-thin shell during the air tightness detection of the battery monomer, and can also reduce the risk of shell welding burst of the battery monomer.

[0037] In some embodiments, P3 satisfies the following condition: 80Pa≤P3≤300Pa, which further reduces the risk of plastic deformation of the ultra-thin shell during the air tightness detection of the battery monomer.

[0038] In some embodiments, the gas is any one or several of helium, hydrogen, argon and nitrogen. Using the above gas as the tracer gas for air tightness detection of the battery monomer facilitates detection.

[0039] The above description is only a summary of the technical solutions of the present application. In order to more clearly understand the technical means of the present application, the specific embodiments of the present application can be implemented in accordance with the content of the description, and in order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the following specific embodiments of the present application are described. BRIEF DESCRIPTION OF DRAWINGS

[0040] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the embodiments of the present application. Obviously, the drawings described below are only some of the embodiments of the present application, and for those skilled in the art, other drawings can also be obtained from these drawings without any creative effort.

[0041] Fig. 1 is a structural schematic diagram of a vehicle according to some embodiments of the present application;

[0042] Fig. 2 is an exploded view of a battery according to some embodiments of the present application;

[0043] Fig. 3 is a structural schematic diagram of a battery module according to some embodiments of the present application;

[0044] Fig. 4 is an exploded structural schematic diagram of a battery cell according to some embodiments of the present application;

[0045] Fig. 5 is a structural schematic diagram of a battery cell according to some other embodiments of the present application;

[0046] Fig. 6 is an exploded schematic diagram of a gas tightness detection device according to some embodiments of the present application;

[0047] Fig. 7 is a structural schematic diagram of a cover of a gas tightness detection device according to some embodiments of the present application;

[0048] Fig. 8 is a partial schematic diagram of a gas injection pipeline of a gas tightness detection device according to some embodiments of the present application;

[0049] Fig. 9 is a structural schematic diagram of a bin body of a gas tightness detection device according to some embodiments of the present application;

[0050] Fig. 10 is a flow schematic diagram of a gas tightness detection method according to some embodiments of the present application.

[0051] Legend of reference signs:

[0052] 1000, vehicle; 100, battery; 110, battery box; 200, controller; 300, motor; 10, upper cover; 30, bin body; 400, battery module; 20, battery cell; 22, shell; 21, end cover; 26, electrode terminal; 23, electrode assembly; 24, liquid injection hole; 500, gas tightness detection device; 50, bin body; 51, accommodating groove; 511, first side edge; 512, second side edge; 513, reinforcing portion; 60, cover; 70, vacuum pipeline; 71, vacuum collection pipe; 72, vacuum connection pipe; 73, vacuum branch pipe; 80, gas injection pipeline; 81, gas injection collection pipe; 82, gas injection connection pipe; 83, gas injection branch pipe; 84, gas injection passage; 85, vacuum passage; 86, vacuum suction cup. DETAILED DESCRIPTION

[0053] The embodiments of the present application will be further described in details below with reference to the drawings and examples. The detailed description of the following examples and the drawings are used to exemplarily illustrate the principles of the present application, but cannot be used to limit the scope of the present application, i.e., the present application is not limited to the described examples.

[0054] In the description of the present application, it should be noted that, unless otherwise specified, the meaning of "a plurality of" is more than two; the orientation or positional relationship indicated by the terms "upper", "lower", "left", "right", "inner", "outer" and the like merely indicates or infers the device or element referred to in the description of the present application and simplifies the description, and therefore cannot be understood as a limitation on the present application. In addition, the terms "first", "second", "third" and the like are only for descriptive purposes and cannot be understood as indicating or inferring relative importance. "Vertical" is not strictly vertical, but within the allowable range of error. "Parallel" is not strictly parallel, but within the allowable range of error.

[0055] In the present application, the phrase "embodiment" means that the specific features, structures or characteristics described in conjunction with the embodiment can be included in at least one embodiment of the present application. The appearance of this phrase at various places in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment to other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described in the present application can be combined with other embodiments.

[0056] The orientation words appearing in the following description are the directions shown in the drawings, and are not a limitation on the specific structure of the present application. In the description of the present application, it should also be noted that, unless otherwise explicitly specified and limited, the terms "mounting", "connection", "connection" should be broadly understood, for example, it can be a fixed connection, or a detachable connection, or an integral connection; it can be directly connected, or indirectly connected through an intermediate medium. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0057] In the present application, the battery cell can include a lithium ion secondary battery cell, a lithium ion primary battery cell, a lithium-sulfur battery cell, a sodium lithium ion battery cell, a sodium ion battery cell or a magnesium ion battery cell, etc. The present application embodiments are not limited thereto. The battery cell can be in the shape of a cylinder, a flat body, a cuboid or other shapes, etc. The present application embodiments are also not limited thereto. The battery cell is generally divided into three types according to the packaging method: cylindrical battery cell, square battery cell and soft package battery cell, and the present application embodiments are also not limited thereto.

[0058] The battery mentioned in the embodiments of the present application refers to a single physical module including one or more battery monomers to provide higher voltage and capacity. For example, the battery mentioned in the present application can include a battery module or a battery pack, etc. The battery generally includes a box for packaging one or more battery monomers. The box can avoid the influence of liquid or other foreign matters on the charging or discharging of the battery monomers.

[0059] The battery monomer includes an electrode assembly and an electrolyte, and the electrode assembly is composed of a positive electrode sheet, a negative electrode sheet and a separator film. The battery monomer mainly relies on the movement of metal ions between the positive electrode sheet and the negative electrode sheet to work. The positive electrode sheet includes a positive electrode current collector and a positive electrode active material layer, and the positive electrode active material layer is coated on the surface of the positive electrode current collector. The current collector without the positive electrode active material layer protrudes from the current collector with the positive electrode active material layer, and the current collector without the positive electrode active material layer is laminated as a positive electrode tab. Taking a lithium ion battery as an example, the material of the positive electrode current collector can be aluminum, and the positive electrode active material can be lithium cobaltate, lithium iron phosphate, ternary lithium or lithium manganate, etc. The negative electrode sheet includes a negative electrode current collector and a negative electrode active material layer, and the negative electrode active material layer is coated on the surface of the negative electrode current collector. The current collector without the negative electrode active material layer protrudes from the current collector with the negative electrode active material layer, and the current collector without the negative electrode active material layer is laminated as a negative electrode tab. The material of the negative electrode current collector can be copper, and the negative electrode active material can be carbon or silicon, etc. The material of the separator film can be PP (polypropylene) or PE (polyethylene), etc. In addition, the electrode assembly can be a winding type structure or a laminated type structure, and the embodiments of the present application are not limited thereto.

[0060] The battery monomer disclosed in the embodiments of the present application can be used in an electric device such as a vehicle, a ship or an aircraft, etc. The power supply system of the electric device can be composed of the battery monomer and the battery disclosed in the present application, so that the stability of the battery performance and the service life of the battery can be improved.

[0061] Before the electrode liquid is injected, the battery monomer needs to be subjected to airtightness detection by injecting gas into the injection hole. With the continuous improvement of the energy density of the battery monomer, the shell of the battery monomer is becoming thinner and thinner, for example, the thickness of some steel shell is only 75 μm, and the thickness of some aluminum shell is only 300 μm. The shell part around the injection hole of the battery monomer bears a large pressure during airtightness detection, and the risk of irreversible plastic deformation also increases accordingly.

[0062] In order to solve the above technical problems, the application provides a cutting device of a battery, which comprises a bearing structure and a cutting structure. The bearing structure comprises a frame and a carrying plate arranged in the frame, and the carrying plate is used for carrying a battery monomer or a battery module. The cutting structure is located beside the frame, and the cutting structure comprises a driving assembly and a cutting machine connected with the driving assembly. The driving assembly is used for driving the cutting machine to move along a first direction and a second direction respectively. The first direction is a height direction of the bearing structure, and the second direction is a cutting direction of the cutting machine. The first direction and the second direction are arranged in an intersecting manner. In the above scheme, during cutting, the battery monomer or the battery module to be cut is first placed on the carrying plate, then the height of the cutting machine is adjusted according to the cutting position of the battery monomer or the battery module through the driving assembly, and then the cutting machine is driven to move along the second direction through the driving assembly, so as to realize automatic cutting of the battery monomer or the battery module. The battery monomer or the battery module can be cut by the application, and automatic cutting is realized, so that the cutting efficiency of the battery is improved.

[0063] The application provides a power consumption device using a battery as a power supply. The power consumption device can be, but is not limited to, a mobile phone, a tablet computer, a notebook computer, an electric toy, an electric tool, an electric vehicle, an electric automobile, a ship, a spacecraft, and the like. The electric toy can include a fixed or mobile electric toy, such as a game console, an electric automobile toy, an electric ship toy, an electric aircraft toy, and the like. The spacecraft can include an airplane, a rocket, a space shuttle, a spacecraft, and the like.

[0064] The following embodiments are described by taking a power consumption device of an embodiment of the application as a vehicle 1000 for convenience of description.

[0065] Please refer to FIG. 1, which is a structural schematic diagram of the vehicle 1000 provided by some embodiments of the application. The vehicle 1000 can be a fuel automobile, a gas automobile, or a new energy automobile. The new energy automobile can be a pure electric automobile, a hybrid electric automobile, or a range extended automobile. The vehicle 1000 is internally provided with a battery 100, which can be arranged at the bottom, the head, or the tail of the vehicle 1000. The battery 100 can be used for power supply of the vehicle 1000, for example, the battery 100 can be used as an operating power supply of the vehicle 1000. The vehicle 1000 can further include a controller 200 and a motor 300. The controller 200 is used to control the battery 100 to supply power to the motor 300, for example, to meet the power demand of the vehicle 1000 during starting, navigation, and driving.

[0066] In some embodiments of the application, the battery 100 can not only be used as an operating power supply of the vehicle 1000, but also be used as a driving power supply of the vehicle 1000, to replace or partially replace fuel or natural gas to provide driving power for the vehicle 1000.

[0067] Please refer to FIG. 2, which is an exploded view of the battery 100 according to some embodiments of the present application. The battery 100 includes a battery box 110 and battery cells 20. In some embodiments, the battery box 110 can include an upper cover 10 and a box body 30, the upper cover 10 and the box body 30 are coupled to each other, and the upper cover 10 and the box body 30 together define a receiving cavity for accommodating the battery cells 20. The box body 30 can be a hollow structure with one end open, and the upper cover 10 can be a plate-shaped structure, which is coupled to the open end of the box body 30 to define the receiving cavity together with the box body 30. Alternatively, the upper cover 10 and the box body 30 can both be hollow structures with one side open, and the open side of the upper cover 10 is coupled to the open side of the box body 30. Of course, the battery box 110 formed by the upper cover 10 and the box body 30 can have various shapes, such as a cylinder, a cuboid, etc.

[0068] FIG. 3 is a structural schematic diagram of the battery module 400 shown in FIG. 2. In the battery 100, the battery cells 20 can be multiple, and the multiple battery cells 20 can be connected in series, in parallel, or in a mixed connection. The mixed connection means that some of the multiple battery cells 20 are connected in series and some are connected in parallel. The multiple battery cells 20 can be directly connected in series, in parallel, or in a mixed connection, and then the whole of the multiple battery cells 20 is accommodated in the box body. Of course, the battery 100 can also be in the form of multiple battery cells 20 connected in series, in parallel, or in a mixed connection to form a battery module, and multiple battery modules are connected in series, in parallel, or in a mixed connection to form a whole, which is accommodated in the box body. The battery 100 can also include other structures, for example, the battery 100 can also include a busbar component for realizing the electrical connection between the multiple battery cells 20.

[0069] Each of the battery cells 20 can be a secondary battery cell or a primary battery cell, and can also be a lithium-sulfur battery cell, a sodium-ion battery cell, or a magnesium-ion battery cell, but is not limited thereto. The battery cell 20 can be in the shape of a cylinder, a flat body, a cuboid, or other shapes, etc.

[0070] Please refer to FIG. 4, which is an exploded structural schematic diagram of the battery cell 20 according to some embodiments of the present application. The battery cell 20 refers to the smallest unit that constitutes a battery. As shown in FIG. 3, the battery cell 20 includes an end cover 21, a shell 22, an electrode assembly 23, and other functional components.

[0071] The end cover 21 refers to a component that covers the opening of the shell 22 to isolate the internal environment of the battery cell 20 from the external environment. Without limitation, the shape of the end cover 21 can be adapted to the shape of the shell 22 to fit the shell 22. Optionally, the end cover 21 can be made of a material with certain hardness and strength, such as aluminum alloy, so that the end cover 21 is not easily deformed when subjected to extrusion collision, enabling the battery cell 20 to have higher structural strength and improved safety performance. The end cover 21 can be provided with functional components such as the electrode terminal 26. The electrode terminal 26 can be used to electrically connect with the electrode assembly 23 for outputting or inputting the electrical energy of the battery cell 20. In some embodiments, the end cover 21 can also be provided with a pressure relief mechanism for relieving the internal pressure of the battery cell 20 when the internal pressure or temperature reaches a threshold value. The material of the end cover 21 can also be various, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc., which are not specially limited in the embodiments of the present application. In some embodiments, an insulating piece can also be provided on the inner side of the end cover 21, which can be used to isolate the electrical connection components in the shell 22 from the end cover 21 to reduce the risk of short circuit. Exemplarily, the insulating piece can be plastic, rubber, etc.

[0072] The shell 22 is a component for fitting the end cover 21 to form the internal environment of the battery cell 20, which can be used to accommodate the electrode assembly 23, electrolyte and other components. The shell 22 and the end cover 21 can be independent components, and an opening can be provided on the shell 22, and the end cover 21 is covered on the opening to form the internal environment of the battery cell 20. In some examples, the shell 22 is a hollow structure with one side opening, and the end cover 21 is one that covers the opening of the shell 22. In other examples, the shell 22 is a hollow structure with two side openings, and the end cover 21 is two, which respectively cover the two openings of the shell 22. Without limitation, the end cover 21 and the shell 22 can also be integrated, specifically, the end cover 21 and the shell 22 can form a common connecting surface before other components enter the shell, and when it is necessary to encapsulate the internal environment of the shell 22, the end cover 21 is covered on the shell 22. The shell 22 can be various shapes and sizes, such as cuboid, cylinder, hexagonal prism, etc. Specifically, the shape of the shell 22 can be determined according to the specific shape and size of the electrode assembly 23. The material of the shell 22 can be various, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc., which are not specially limited in the embodiments of the present application.

[0073] The electrode assembly 23 is a component in which electrochemical reactions occur in the battery cell 20. One or more electrode assemblies 23 can be contained within the case 22. The electrode assembly 23 is mainly formed by winding or layering a positive electrode sheet and a negative electrode sheet, and a separator is generally provided between the positive electrode sheet and the negative electrode sheet. The positive electrode sheet and the negative electrode sheet each have a portion with an active material constituting a main body of the electrode assembly 23, and a portion without the active material constituting a tab. The positive electrode tab and the negative electrode tab can be located together at one end of the main body or at opposite ends of the main body. During charging and discharging of the battery, the positive electrode active material and the negative electrode active material react with an electrolyte, and the tabs connect to the electrode terminal 26 to form a current loop.

[0074] FIG. 5 is a structural schematic diagram of a battery cell according to another embodiment of the present application; FIG. 6 is an exploded schematic diagram of a gas tightness detection device according to some embodiments of the present application; and FIG. 8 is a partial schematic diagram of a gas injection line of the gas tightness detection device according to some embodiments of the present application.

[0075] In a first aspect, in combination with FIGS. 5 and 6, and 8, the embodiments of the present application provide a gas tightness detection device 500 for a battery cell 20, which includes a bin body 50 and a cover body 60. The cover body 60 is arranged on the bin body 50, and the cover body 60 and the bin body 50 form a cavity for accommodating the battery cell 20. The cover body 60 is provided with a vacuum line 70 and a gas injection line 80. The vacuum line 70 is in communication with the cavity, and the end of the gas injection line 80 is in contact with the circumferential side of the liquid injection hole 24 of the battery cell 20 and is in communication with the liquid injection hole 24 of the battery cell 20. The vacuum line 70 is used to be tapped to a gas detector. The gas injection line 80 is provided with a gas injection channel 84 and a vacuum channel 85. The gas injection channel 84 is used to correspond to the liquid injection hole 24, and the vacuum channel 85 is used to correspond to the circumferential side of the liquid injection hole 24.

[0076] The bin body 50 can be in the shape of a cuboid, a square, or a cylinder, and correspondingly, the cover body 60 is also in the shape of a cuboid, a square, or a cylinder with matching dimensions. One battery cell 20 or multiple battery cells 20 can be placed in the cavity, and the gas tightness of the multiple battery cells 20 can be detected simultaneously.

[0077] A through hole can be provided on the cover body 60, and the vacuum line 70 and the gas injection line 80 are respectively inserted into the through hole and fixed to the cover body 60. The vacuum line 70 is connected to a vacuum device to perform vacuumization on the cavity. The gas injection line 80 extends into the cavity and is inserted into the liquid injection hole 24 of the battery cell 20. Since the vacuum line 70 is only in communication with the cavity and does not contact the battery cell 20, the interior of the battery cell 20 will not be affected when the cavity is vacuumized through the vacuum line 70.

[0078] When the gas is injected into the interior of the battery cell 20, the interior of the battery cell 20 is in a positive pressure state because the cavity is in a vacuum state. For example, if the absolute pressure of the vacuum pipeline 70 is P2, and the injection pressure of the gas injected into the interior of the battery cell 20 by the injection pipeline 80 is P3, then P4 = P2 + P3, and F2 = P4 * S2, where F2 is the bearing capacity of the battery cell 20, and S2 is the contact area of the injection pipeline 80 and the shell 22 of the battery cell 20. The positive pressure injection can improve the bearing capacity of the battery cell 20.

[0079] After the battery cell 20 is in a positive pressure state, if the battery cell 20 has a leak, the tracer gas in the interior of the battery cell 20 leaks to the cavity, and is branched to an external gas detector (such as a mass spectrometer) through the vacuum pipeline 70 of the cavity 50. The mass spectrometer quantitatively analyzes the amount of tracer gas leaked by the battery cell 20, and determines whether the battery cell 20 is a defective product according to a preset specification. When the leakage rate of the battery cell 20 is greater than the specification value, the battery cell 20 is a defective product, otherwise, the battery cell 20 is a good product.

[0080] The injection passage 84 can be arranged in the middle of each injection branch pipeline 83 of the injection pipeline 80, and the injection passage 84 is connected to a gas source. The injection passage 84 is located above the liquid injection hole 24 and communicates with the liquid injection hole 24. The injection passage 84 is used to inject gas into the interior of the battery cell 20, and the gas tightness of the battery cell 20 is detected.

[0081] The vacuum passage 85 can be arranged beside the injection passage 84, and the vacuum passage 85 is connected to a vacuum device, such as a vacuum pump. The vacuum passage 85 does not overlap the liquid injection hole 24, and the vacuum passage 85 is located on the shell 22 around the liquid injection hole 24.

[0082] In the above scheme, when the gas tightness of the battery cell 20 is tested, the battery cell 20 is first placed on the cavity 50, and then the cover 60 is arranged on the cavity 50. Then, the cavity is vacuumed through the vacuum pipeline 70, and the gas is injected into the interior of the battery cell 20 through the injection pipeline 80 to detect the gas tightness. The interior of the battery cell 20 is in a positive pressure state relative to the outside, which reduces the risk of plastic deformation of the ultra-thin shell 22 of the battery cell 20 when the gas tightness of the battery cell 20 is tested. The vacuum passage 85 of the injection pipeline 80 can be used to vacuum adsorb the part of the shell 22 around the liquid injection hole 24 of the battery cell 20, thereby further reducing the risk of plastic deformation of the ultra-thin shell 22 of the battery cell 20 when the gas tightness of the battery cell 20 is tested.

[0083] FIG. 7 is a structural schematic view of a cover of a gas tightness detection device according to some embodiments of the present application.

[0084] As shown in FIG. 7, in some embodiments, the gas injection pipeline 80 includes a gas injection manifold 81, a gas injection connecting pipe 82, and a plurality of gas injection branch pipes 83. The gas injection connecting pipe 82 is connected to the gas injection manifold 81. The plurality of gas injection branch pipes 83 are respectively connected to the gas injection connecting pipe 82, and are respectively used to communicate with the plurality of liquid injection holes 24 one by one.

[0085] For example, the plurality of battery monomers 20 are sequentially and spacedly arranged along the length direction of the bin body 50, and the gas injection connecting pipe 82 also extends along the length direction of the bin body 50. The plurality of gas injection branch pipes 83 are arranged below the gas injection connecting pipe 82, and are sequentially and spacedly arranged along the length direction of the bin body 50. The liquid injection hole 24 of each battery monomer 20 corresponds to one gas injection branch pipe 83. The gas injection manifold 81 is arranged above the gas injection connecting pipe 82.

[0086] In the above scheme, the plurality of gas injection branch pipes 83 are sequentially connected through the gas injection connecting pipe 82, and are connected to the gas injection manifold 81, so that the plurality of battery monomers 20 can be simultaneously subjected to the air tightness detection.

[0087] In some embodiments, the part of the gas injection pipeline 80 used to contact the side of the liquid injection hole 24 is provided with a vacuum suction cup 86, and the vacuum suction cup 86 communicates with the vacuum channel 85.

[0088] The vacuum suction cup 86 can be in the shape of a circular truncated cone, and the side with a larger area is used to contact the part of the shell 22 on the side of the liquid injection hole 24, so as to suck the part.

[0089] If the absolute pressure of the vacuum adsorption of the gas injection pipeline 80 is P1, and the contact area of the vacuum suction cup 86 and the shell 22 of the battery monomer 20 is S1, then F1=9.8×10E-02×(101000-P1)×S1, wherein F1 is the adsorption force of the gas injection pipeline 80 to the battery monomer 20, and the adsorption of the gas injection pipeline 80 can further improve the load of the shell 22 of the battery monomer 20.

[0090] In the above scheme, by arranging the vacuum suction cup 86 at the end of the vacuum channel 85, the contact area of the gas injection pipeline 80 and the part of the shell 22 on the side of the liquid injection hole 24 can be increased, so as to improve the vacuum adsorption force of the gas injection pipeline 80 to the battery monomer 20.

[0091] In some embodiments, the number of the vacuum channels 85 is a plurality, and the plurality of vacuum channels 85 are arranged in a ring around the gas injection channel 84.

[0092] The vacuum channels 85 can be uniformly distributed on the outer periphery of the gas injection channel 84, so that the part outside the gas injection channel 84 can have the vacuum channels 85, and thus can contact each position on the side of the liquid injection hole 24.

[0093] In the above scheme, by arranging the vacuum channels 85 on the circumferential side of the gas injection channel 84, the vacuum adsorption force of the gas injection pipeline 80 on the battery monomer 20 and the uniformity of the vacuum adsorption force can be improved.

[0094] In some embodiments, the vacuum pipeline 70 includes a vacuum collecting pipe 71, a vacuum connecting pipe 72, and a plurality of vacuum branch pipes 73. The vacuum connecting pipe 72 is connected with the vacuum collecting pipe 71. The plurality of vacuum branch pipes 73 are connected with the vacuum connecting pipe 72 respectively, and are used to communicate with the cavities respectively.

[0095] For example, the plurality of battery monomers 20 are arranged along the length direction of the bin body 50 in sequence and are spaced apart. The vacuum connecting pipe 72 also extends along the length direction of the bin body 50. The plurality of vacuum branch pipes 73 are arranged below the vacuum connecting pipe 72 and are spaced apart along the length direction of the bin body 50 in sequence. The liquid injection hole 24 of each battery monomer 20 corresponds to one of the plurality of vacuum branch pipes 73. The vacuum collecting pipe 71 is arranged above the vacuum connecting pipe 72.

[0096] In the above scheme, by connecting the plurality of vacuum branch pipes 73 in sequence through the vacuum connecting pipe 72 and connecting the vacuum connecting pipe 72 with the vacuum collecting pipe 71, the contact area between the vacuum pipeline 70 and the cover body 60 can be increased, so that the efficiency of vacuumizing the cavities by the vacuum pipeline 70 can be improved.

[0097] FIG. 9 is a structural schematic view of a bin body of a gas tightness detection device according to some embodiments of the present application.

[0098] As shown in FIG. 9, in some embodiments, a plurality of accommodating grooves 51 are arranged in the bin body 50. The plurality of accommodating grooves 51 are spaced apart, and each of the accommodating grooves 51 is used to accommodate one of the battery monomers 20.

[0099] The plurality of accommodating grooves 51 can be arranged along the length direction of the bin body 50, or the plurality of accommodating grooves 51 can be arranged in a matrix. The shape and size of each of the accommodating grooves 51 are matched with the shape and size of the battery monomer 20 respectively.

[0100] In the above scheme, by fixing the plurality of battery monomers 20 one by one through the plurality of accommodating grooves 51 respectively, the stability of each battery monomer 20 during the gas tightness detection can be improved.

[0101] After the battery monomer 20 is placed in the accommodating groove 51, the end of the battery monomer 20 will slightly protrude from the accommodating groove 51. If the cover body 60 is directly arranged on the bin body 50, and the gas is injected into the interior of the battery monomer 20 through the gas injection pipeline 80, the battery monomer 20 is likely to be pressed to produce a pressure mark at the edge of the second side edge 512 during the pressing process.

[0102] In some embodiments, the accommodation groove 51 comprises a first side edge 511 and a second side edge 512 connected with the first side edge 511, the second side edge 512 has a length greater than that of the first side edge 511, and the second side edge 512 is provided with a reinforcing portion extending towards the cover body 60.

[0103] The second side edge 512 corresponds to the side with a larger area of the battery monomer 20, and the embodiment of the present application is provided with the reinforcing portion 513 at the second side edge 512 of the accommodation groove 51, which supports the side with a larger area of the battery monomer 20.

[0104] In the above scheme, by providing the reinforcing portion 513 at the second side edge 512 with a relatively longer length, the side with a larger area of the battery monomer 20 can be protected from being exposed to the accommodation groove 51, and to a certain extent, the side with a larger area of the battery monomer 20 can be prevented from being indented when the air tightness of the battery monomer 20 is detected.

[0105] In the third aspect, the embodiment of the present application also provides a system for detecting the air tightness of the battery monomer 20, which comprises the air tightness detection device 500 of any of the above embodiments.

[0106] FIG. 10 is a flowchart of a method for detecting the air tightness of the battery monomer 20 according to some embodiments of the present application.

[0107] As shown in FIG. 10, in the third aspect, the embodiment of the present application also provides a method for detecting the air tightness of the battery monomer 20, which adopts the air tightness detection device 500 of any of the above embodiments, and the method comprises the following steps:

[0108] S10, placing the battery monomer 20 in the bin body 50.

[0109] S20, covering the bin body 50 with the cover body 60;

[0110] S30, vacuumizing the cavity through the vacuum pipeline 70;

[0111] S40, injecting gas into the interior of the battery monomer 20 through the gas injection pipeline 80;

[0112] S50, detecting whether there is gas leakage in the interior of the battery monomer 20 through the gas detector.

[0113] In the above scheme, the interior of the battery monomer 20 forms a positive pressure relative to the exterior, which reduces the risk of plastic deformation of the ultra-thin shell 22 when the battery monomer 20 is detected for air tightness.

[0114] In some embodiments, the step of vacuumizing the cavity through the vacuum pipeline 70 is preceded by:

[0115] S50, vacuum is drawn on the vacuum passage 85 of the gas injection pipeline 80, so that the battery monomer 20 is adsorbed by the gas injection pipeline 80 along the circumferential side of the liquid injection hole 24.

[0116] In the above scheme, the shell 22 part around the liquid injection hole 24 of the battery monomer 20 can be vacuum adsorbed by the vacuum passage 85 of the gas injection pipeline 80, thereby further reducing the risk of plastic deformation of the ultra-thin shell 22 when the battery monomer 20 is subjected to air tightness detection.

[0117] In some embodiments, the vacuum adsorption absolute pressure of the gas injection pipeline 80 on the battery monomer 20 is P1, and P1 satisfies the following condition: 20Pa≤P1≤20000Pa.

[0118] The vacuum adsorption absolute pressure is the absolute pressure in the vacuum passage 85 of the gas injection pipeline 80. The vacuum adsorption absolute pressure P1 of the battery monomer 20 can be any value between 20Pa and 20000Pa, for example, the vacuum adsorption absolute pressure P1 can be 20Pa, 30Pa, 100Pa, 500Pa, 1000Pa, 10000Pa or 20000Pa, etc., as long as it is within the range of 20Pa-20000Pa.

[0119] In the above scheme, the limit vacuum degree of the gas injection pipeline 80 is not exceeded, and the adsorption force of the gas injection pipeline 80 on the battery monomer 20 is ensured to a certain extent.

[0120] In some embodiments, P1 satisfies the following condition: 20Pa≤P1≤200Pa.

[0121] The vacuum adsorption absolute pressure P1 of the battery monomer 20 can be any value between 20Pa and 200Pa, for example, the vacuum adsorption absolute pressure P1 can be 20Pa, 50Pa, 80Pa, 120Pa, 150Pa, 180Pa or 2000Pa, etc.

[0122] The embodiments of the present application further reduce the difficulty of the vacuum degree requirement of the vacuum equipment when vacuumizing.

[0123] In some embodiments, the vacuum absolute pressure of the vacuum pipeline 70 is P2, and P2 satisfies the following condition: 0Pa<P2≤40Pa.

[0124] The vacuum absolute pressure P2 of the vacuum pipeline 70 can be any value between 0Pa and 40Pa, for example, the vacuum adsorption absolute pressure P1 can be 5Pa, 10Pa, 20Pa, 25Pa, 30Pa, 35Pa or 40Pa, etc., as long as it is within the range of 0Pa-40Pa.

[0125] In the above scheme, by limiting the vacuum absolute pressure P2 of the vacuum pipeline 70 to 0 < P2 ≤ 40 Pa, the foolproofing of detecting whether the pressure sensor is damaged or the pipeline is blocked can be applied, and the influence of the gas leakage in the cavity to the inside of the battery monomer 20 to affect the air tightness detection can be reduced.

[0126] In some embodiments, P2 satisfies the following condition: 5 Pa ≤ P2 ≤ 40 Pa.

[0127] The vacuum absolute pressure P2 of the vacuum pipeline 70 can be any value between 5 Pa and 40 Pa, for example, the vacuum suction absolute pressure P1 can be 5 Pa, 15 Pa, 18 Pa, 33 Pa, 37 Pa, 38 Pa, or 40 Pa, etc.

[0128] The embodiments of the present application further facilitate the foolproofing of detecting whether the pressure sensor is damaged or the pipeline is blocked.

[0129] In some embodiments, the injection pressure P3 of the gas injection pipeline 80 injecting gas into the inside of the battery monomer 20 satisfies the following condition: 50 Pa ≤ P3 ≤ 300 Pa.

[0130] The injection pressure P3 can be any value between 50 Pa and 300 Pa, for example, the vacuum suction absolute pressure P1 can be 50 Pa, 80 Pa, 100 Pa, 150 Pa, 200 Pa, 250 Pa, or 300 Pa, etc., as long as it is within the range of 50 Pa to 300 Pa.

[0131] In the above scheme, by limiting the injection pressure P3 to 50 Pa ≤ P3 ≤ 300 Pa, the risk of plastic deformation of the ultra-thin shell 22 of the battery monomer 20 during air tightness detection can be reduced, and the risk of the shell 22 of the battery monomer 20 being blown apart by the welding line can also be reduced.

[0132] In some embodiments, P3 satisfies the following condition: 80 Pa ≤ P3 ≤ 300 Pa.

[0133] The injection pressure P3 can be any value between 80 Pa and 300 Pa, for example, the vacuum suction absolute pressure P1 can be 80 Pa, 90 Pa, 120 Pa, 160 Pa, 180 Pa, 260 Pa, or 300 Pa, etc.

[0134] The embodiments of the present application further reduce the risk of plastic deformation of the ultra-thin shell 22 of the battery monomer 20 during air tightness detection.

[0135] In some embodiments, the gas is any one or several of helium, hydrogen, argon, and nitrogen. Using the above gas as the tracer gas for air tightness detection of the battery monomer 20 facilitates detection.

[0136] According to some embodiments of the present application, the present application provides a kind of airtight detection device 500 of battery cell 20, including warehouse body 50 and cover body 60, cover body 60 is covered on warehouse body 50, cover body 60 and warehouse body 50 form the cavity for accommodating battery cell 20;Vacuum line 70 and gas injection line 80 are arranged on cover body 60, vacuum line 70 is communicated with the cavity, the end of gas injection line 80 is in contact with the circumferential side of battery cell 20 injection hole 24, and is communicated with the injection hole 24 of battery cell 20.Gas injection line 80 is provided with gas injection channel 84 and vacuum channel 85, gas injection channel 84 is used to correspond with injection hole 24, vacuum channel 85 is used to correspond with the circumferential side of injection hole 24.

[0137] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present application, and not to limit them; Although the present application is described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement to part or all of the technical features; And these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application, and they should be covered in the scope of the claims and the specification of the present application. Especially, as long as there is no structural conflict, the technical features mentioned in each embodiment can be combined in any way. The present application is not limited to the specific embodiments disclosed in the text, but includes all technical solutions falling within the scope of the claims.

Claims

1. A battery cell airtightness detection device, comprising: a bin body; a cover body, the cover body being arranged on the bin body to form a cavity for accommodating a battery cell, the cover body being provided with a vacuum pipeline and a gas injection pipeline, the vacuum pipeline being in communication with the cavity, an end of the gas injection pipeline being in contact with a circumferential side of a liquid injection hole of the battery cell and in communication with the liquid injection hole of the battery cell, the vacuum pipeline being used for tapping a gas detector; the gas injection pipeline being provided with a gas injection channel and a vacuum channel, the gas injection channel being used for corresponding to the liquid injection hole, and the vacuum channel being used for corresponding to the circumferential side of the liquid injection hole.

2. The air tightness testing apparatus of claim 1, wherein, the gas injection pipeline comprising: a gas injection manifold; a gas injection connecting pipe connected to the gas injection manifold; a plurality of gas injection branch pipes, each of the gas injection branch pipes being connected to the gas injection connecting pipe, and each of the gas injection branch pipes being used for communicating with one of the liquid injection holes one by one.

3. The air tightness testing apparatus of claim 1, wherein, a vacuum suction cup provided on a portion of the gas injection pipeline in contact with the circumferential side of the liquid injection hole, the vacuum suction cup being in communication with the vacuum channel.

4. The air tightness testing apparatus of any one of claims 1-3, wherein, a plurality of the vacuum channels, the plurality of the vacuum channels being arranged in a ring around a circumference of the gas injection channel.

5. The air tightness testing apparatus of any one of claims 1-4, wherein, the vacuum pipeline comprising: a vacuum manifold; a vacuum connecting pipe connected to the vacuum manifold; a plurality of vacuum branch pipes, each of the vacuum branch pipes being connected to the vacuum connecting pipe, and each of the vacuum branch pipes being used for communicating with the cavity.

6. The air tightness testing apparatus of any one of claims 1-5, wherein, a plurality of accommodating grooves arranged in the bin body, the plurality of the accommodating grooves being arranged at intervals, and each of the accommodating grooves being used for accommodating one of the battery cells.

7. The air tightness testing apparatus of claim 6, wherein, the accommodating groove comprising: a first side; a second side connected to the first side, the second side being longer than the first side, and the second side being provided with a reinforcing portion extending towards the cover body. 8.A battery cell airtightness detection system, comprising the airtightness detection device according to any one of claims 1 to 7. 9.A battery cell airtightness detection method, using the airtightness detection device according to any one of claims 1 to 7, the airtightness detection method comprising the following steps: placing a battery cell in the bin body; arranging the cover body on the bin body; vacuumizing the cavity through the vacuum pipeline; injecting gas into the battery cell through the gas injection pipeline; detecting whether there is gas leakage in the battery cell through the gas detector.

10. The method of leak testing according to claim 9, wherein, before the step of vacuumizing the cavity through the vacuum pipeline, comprising: vacuumizing the vacuum channels of the gas injection pipeline to enable the battery cell to be adsorbed by the gas injection pipeline along the circumferential side of the liquid injection hole.

11. The method of leak testing according to claim 10, wherein, an absolute pressure of the vacuum adsorption of the battery cell by the gas injection pipeline being P1, the P1 satisfying the following condition: 20 Pa≤P1≤20000 Pa.

12. The method of leak testing according to claim 11, wherein, the P1 satisfying the following condition: 20 Pa≤P1≤200 Pa.

13. The method of leak testing according to any one of claims 9-12, wherein, an absolute pressure of the vacuum pipeline being P2, the P2 satisfying the following condition: 0 Pa 14. The method of leak testing according to claim 13, wherein, the P2 satisfying the following condition: 5 Pa≤P2≤40 Pa.

15. The method of leak testing according to any one of claims 9-14, wherein, The injection pressure of the gas injection pipeline injecting gas into the battery monomer is P3, and the P3 satisfies the following condition: 50 Pa≤P3≤300 Pa.

16. The method of leak testing according to claim 15, wherein, The P3 satisfies the following condition: 80 Pa≤P3≤300 Pa.

17. The method of leak testing according to any one of claims 9-16, wherein, The gas is any one or several of helium, hydrogen, argon and nitrogen.

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