Battery cells, battery devices, electrical equipment, and welding quality testing methods

Abstract

The present application discloses a battery cell, a battery device, an electrical device and a welding quality detection method, which relates to the field of battery production detection technology. The battery cell includes a main body and an output pole arranged on the main body. The side of the output pole away from the main body is a welding surface. A groove is provided on the welding surface. The welding surface is used to weld with a conductive connector to form a weld. The groove intersects with the weld, so that the ultrasonic wave is emitted toward the intersection of the weld and the groove. The reflected signal intensity of the ultrasonic wave at the target position at different depths is detected, and the penetration depth of the weld is obtained according to the reflected signal intensity. The battery cell of the present application can realize full inspection of the welding part of the output pole and the bar, improve the control over the welding quality, and does not require cutting the weld and grinding phase detection. With the assistance of automatic detection equipment, automatic detection can also be realized, and the detection efficiency is high.

Description

Technical Field

[0001] The present application relates to the technical field of battery production testing, and in particular to a battery cell, a battery device, an electrical device, and a welding quality testing method. Background Art

[0002] During the production of power batteries, lasers are used to weld the conductive connectors and the poles together. The conductive connectors generally refer to tabs. However, failure of the welded joints may result in insufficient local strength of the battery device, which may cause abnormal sampling signals and even the risk of overheating and fire. Therefore, it is necessary to control the welding quality between the conductive connectors and the poles. However, due to the limitations of the detection method, the current detection method can only be carried out by random inspections, and the detection efficiency is low. Summary of the Invention

[0003] The main purpose of this application is to propose a battery cell, a battery device, an electrical device and a welding quality detection method, aiming to at least improve the technical problem that the welding quality detection of the pole and the conductive connector in the battery device can only be carried out by random inspection and the detection efficiency is low.

[0004] According to some embodiments of the present application, the present application provides a battery cell, comprising a main body and an output pole arranged on the main body, wherein the side of the output pole away from the main body is a welding surface, a groove is provided on the welding surface, and the welding surface is used to weld with a conductive connector to form a weld, the groove intersects with the weld, and ultrasonic waves are emitted toward the intersection of the weld and the groove, and the reflected signal intensity of the ultrasonic waves at target positions at different depths is detected, and the penetration depth of the weld is obtained according to the reflected signal intensity.

[0005] By setting a groove on the welding surface of the output pole, the weld intersects with the groove, and the ultrasonic wave can be emitted toward the intersection of the weld and the groove to detect the reflected signal intensity of the ultrasonic wave at the target position at different depths. The different reflected signal intensities of the ultrasonic wave in different density media are utilized, and the penetration depth of the weld is obtained according to the reflected signal intensity to achieve non-destructive testing of the weld. This is a non-destructive testing method, which can achieve full inspection of the welding part of the output pole and the bar, improve the control over the welding quality, and does not require cutting the weld and grinding phase testing. With the assistance of automatic testing equipment, automatic testing can also be achieved, and the detection efficiency is high.

[0006] In some embodiments, the number of the groove is one, and both ends of the groove extend to the outer edge of the welding surface respectively.

[0007] By extending both ends of the groove to the outer edge of the weld surface, it is ensured that the weld and the groove can intersect, which facilitates subsequent penetration detection.

[0008] In some embodiments, there are multiple grooves, each of which intersects with the weld, and both ends of each groove extend to the outer edge of the welding surface.

[0009] By setting multiple grooves of different depths and adjusting the position of the ultrasonic transmitter, the ultrasonic wave can be emitted in sequence toward the intersections of the weld and the multiple grooves in a preset emission order. This can be used to quantitatively detect the penetration depth of the weld, and can detect welds with different penetration depths, thereby improving the applicability of the welding quality detection method.

[0010] In some embodiments, the depth of each groove is set in a gradient.

[0011] By setting the groove depth of each groove in a gradient, the detection range of the weld penetration depth can be expanded.

[0012] In some embodiments, the welding surface is a circular surface, and the shape of the weld is annular; or,

[0013] The welding surface is a rectangular surface, and the shape of the weld is a rectangle.

[0014] By setting the welding surface and the weld to a matching shape, the weld and the groove are easily intersected, and the detection of the penetration depth is convenient.

[0015] According to some embodiments of the present application, a welding quality detection method is provided for detecting the weld between the output electrode and the conductive connector of the battery cell described above. The welding quality detection method includes:

[0016] Adjust the position of the ultrasonic transmitter so that the ultrasonic wave is emitted toward the intersection of the weld and the groove.

[0017] detecting the reflected signal intensity of the ultrasonic wave at target positions at different depths;

[0018] The depth is the distance from the upper surface of the conductive connector to the target position in the thickness direction of the conductive connector, where the upper surface is the side of the conductive connector facing away from the output electrode.

[0019] The penetration depth of the weld is obtained according to the intensity of the reflected signal.

[0020] In the above-mentioned embodiment of the present application, by emitting ultrasonic waves toward the intersection of the weld and the groove, detecting the reflected signal intensity of the ultrasonic waves at target positions at different depths, utilizing the different reflected signal intensities of ultrasonic waves in media of different densities, and obtaining the penetration depth of the weld according to the reflected signal intensity, non-destructive testing of the weld can be achieved. This is a non-destructive testing method, which can achieve full inspection of the welding part of the output pole and the bar, improve the control over the welding quality, and does not require cutting the weld and grinding phase detection. With the assistance of automatic detection equipment, automatic detection can also be achieved, and the detection efficiency is high.

[0021] In some embodiments, there are multiple grooves, and the groove depths of the multiple grooves are arranged in a gradient; the step of adjusting the position of the ultrasonic transmitter so that the ultrasonic wave is emitted toward the intersection of the weld and the groove includes:

[0022] Adjust the position of the ultrasonic transmitter so that the ultrasonic wave is emitted in sequence toward the intersections of the weld and the multiple grooves according to the preset emission order;

[0023] The preset emission sequence is: an order in which the groove depth values ​​of the plurality of grooves are arranged from small to large.

[0024] By setting multiple grooves of different depths and adjusting the position of the ultrasonic transmitter, the ultrasonic wave can be emitted in sequence toward the intersections of the weld and the multiple grooves in a preset emission order. This can be used to quantitatively detect the penetration depth of the weld, and can detect welds with different penetration depths, thereby improving the applicability of the welding quality detection method.

[0025] In some embodiments, the step of detecting the reflected signal strength of the ultrasonic wave at target positions at different depths includes:

[0026] The reflected signal intensity of the ultrasonic wave at different depths is obtained in order from small to large depth values.

[0027] By setting the depth values ​​in ascending order to obtain the reflected signal strength of the ultrasonic wave at different depths, it is convenient to operate and also convenient to obtain the trend change graph of the reflected signal strength change.

[0028] In some embodiments, the step of detecting the reflected signal strength of the ultrasonic wave at target positions at different depths includes:

[0029] If the reflected signal strength is greater than or equal to the preset threshold, it is defined as a strong reflected signal;

[0030] If the reflected signal strength is less than the preset threshold, it is defined as a weak reflected signal;

[0031] The step of obtaining the penetration depth of the weld according to the reflected signal strength includes:

[0032] When the intensity of the reflection signal changes from a weak reflection signal to a strong reflection signal, the depth value at this time is recorded, and the depth value is the penetration depth of the weld.

[0033] By defining the numerical range of strong reflection signals and weak reflection signals, the penetration depth of the weld can be directly read from the trend change diagram of the reflection signal intensity-depth, which is very convenient to operate.

[0034] In some embodiments, the welding quality detection method further includes:

[0035] Detecting the reflected signal intensity of the ultrasonic wave in each area at a preset depth position; wherein the preset depth position is the depth position of the lower surface of the conductive connector;

[0036] Determine the outer contour of the weld at a preset depth based on the intensity of the reflected signal;

[0037] The weld width of the weld is obtained according to the outer contour.

[0038] By detecting the reflected signal intensity of the ultrasonic wave in each area at the preset depth position, the outer contour of the weld at the preset depth position is determined according to the reflected signal intensity, and the weld width is obtained according to the outer contour. The weld width data can be obtained through non-destructive and automated testing.

[0039] According to some embodiments of the present application, the present application provides a battery device, including a box body, multiple battery cells, a conductive connector, a sampling piece and a battery management module, the box body is provided with a accommodating cavity, the battery cell is the battery cell described above, the conductive connector is welded to the welding surface of the battery cell to form a weld, and the sampling piece electrically connects the conductive connector and the battery management module.

[0040] The output pole and the sampling piece are electrically connected through a conductive connector, and the electrical signal is transmitted to the battery management module through the sampling piece to realize the monitoring of the battery cell signal. At the same time, the battery cell used can be subjected to ultrasonic non-destructive testing to efficiently detect the penetration depth and width of the weld.

[0041] In some embodiments, the weld is annular in shape, and the weld intersects the groove at multiple locations.

[0042] By setting the weld to a circular weld and intersecting the groove at multiple locations, the convenience of detection can be improved.

[0043] The above description is only an overview of the technical solution of the present application. In order to more clearly understand the technical means of the present application, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying any creative work.

[0045] Figure 1 A schematic structural diagram of a vehicle according to some embodiments of the present application;

[0046] Figure 2 Schematic diagram of the exploded structure of batteries according to some embodiments of the present application;

[0047] Figure 3 This is a schematic structural diagram of the connection between multiple battery cells and conductive connectors of a battery device in some embodiments of the present application;

[0048] Figure 4 This is a schematic structural diagram of a battery cell of a battery device according to some embodiments of the present application;

[0049] Figure 5 for Figure 4 A schematic diagram of the structure of the output pole without the conductive connection welded to the left;

[0050] Figure 6 for Figure 4 The right side shows a schematic diagram of the structure of the output pole with the conductive connector welded to it, the conductive connector and the weld;

[0051] Figure 7 This is a flow chart of a welding quality detection method according to some embodiments of the present application;

[0052] Figure 8 A schematic diagram of a trend change of reflected signal strength and depth in some embodiments of the present application;

[0053] Figure 9 This is a flow chart of a welding quality detection method according to some embodiments of the present application;

[0054] Figure 10 This is a schematic structural diagram of a battery cell in some embodiments of the present application, provided with a first sub-seam and a second sub-seam having different penetration depths;

[0055] Figure 11 for Figure 10 Another schematic diagram showing the trend of reflected signal intensity and depth in the structure;

[0056] Figure 12Another schematic diagram of the trend of reflected signal intensity and depth of grooves with different groove depths in some embodiments of the present application;

[0057] Figure 13 This is a flow chart of a welding quality detection method according to some embodiments of the present application;

[0058] Figure 14 This is a flow chart of a welding quality detection method according to some embodiments of the present application;

[0059] Figure 15 This is a flow chart of a welding quality detection method according to some embodiments of the present application;

[0060] Figure 16 This is a schematic structural diagram of a conductive connector and a battery cell in some embodiments of the present application;

[0061] Figure 17 Schematic diagram of the distribution of reflected signal intensity at a preset depth position during ultrasonic detection in some embodiments of the present application.

[0062] Description of Figure Numbers:

[0063] 1000, vehicle;

[0064] 100, battery device; 200, controller; 300, motor;

[0065] 10. Box body; 11. Upper cover; 12. Box base;

[0066] 20. Battery cells;

[0067] 1. Main body; 2. Output pole; 21. Welding surface; 3. Groove; 4. Welding seam; 41. First sub-seam; 42. Second sub-seam; 5. Conductive connector; 6. Gap.

[0068] The realization of the objectives, functional features and advantages of this application will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0069] The following will be combined with the accompanying drawings to clearly and completely describe the technical solutions in this embodiment. Obviously, the described embodiments are only part of the embodiments of this application, not all of them. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0070] It should be noted that all directional indications in this embodiment (such as up, down, left, right, front, back, etc.) are only used to explain the relative position relationship and movement status between the various components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0071] In addition, the terms "first," "second," and so on, used in this application are for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly specifying the number of the technical features indicated. Therefore, a feature specified as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of this application, "plurality" means at least two, such as two, three, etc., unless otherwise specifically defined.

[0072] In this application, unless otherwise specified or limited, the terms "connection" and "fixation" should be understood in a broad sense. For example, "fixation" can mean fixed connection, detachable connection, or integration; mechanical connection or electrical connection; direct connection or indirect connection through an intermediate medium; internal communication between two elements or interaction between two elements, unless otherwise specified. For those skilled in the art, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0073] In addition, the technical solutions of the various embodiments of this application may be combined with each other, but this must be based on the fact that they can be implemented by a person of ordinary skill in the art. If the combination of technical solutions is mutually inconsistent or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this application. It should be understood that the specific embodiments described herein are only used to explain this application and are not intended to limit this application.

[0074] The descriptions of directions such as "up", "down", "front", "back", "left" and "right" in this application are based on the directions shown in the accompanying drawings and are only used to explain the relative positional relationship between the components in the postures shown in the accompanying drawings. If the specific posture changes, the directional indication will also change accordingly.

[0075] Currently, market developments indicate that power batteries are becoming increasingly widely used. They are not only used in energy storage systems such as hydropower, thermal, wind, and solar power plants, but are also widely used in electric vehicles like electric bicycles, electric motorcycles, and electric vehicles, as well as in military equipment and aerospace. As power battery applications continue to expand, market demand is also growing.

[0076] During the power battery manufacturing process, laser welding is required to connect the conductive connectors to the terminals. The conductive connectors are generally referred to as tabs. Welding forms a welded joint, also known as a weld seam. Failure of the welded joint may lead to insufficient local strength in the battery device, potentially causing sampling signal anomalies and even the risk of overheating and fire. Therefore, the welding quality between the conductive connectors and the terminals must be carefully controlled.

[0077] However, the industry's method of testing welding quality is random inspection, and the inspection efficiency is low. After careful research, the applicant found that for the quality inspection of laser welding joints, penetration detection is an extremely important indicator, and the relevant technology is carried out by metallographic testing of the welded joints. Metallographic testing requires obtaining the inspection cross-section and cutting the bar and pole from the weld. It is a destructive inspection method, so it is impossible to conduct a full inspection, and the overall pass rate can only be estimated through random inspection. In addition, this method is time-consuming and labor-intensive, difficult to automate, and has low inspection efficiency.

[0078] To this end, the present application provides a battery cell, comprising a main body and an output electrode provided on the main body, wherein the side of the output electrode away from the main body is a welding surface, and a groove is provided on the welding surface. The welding surface is used to weld with a conductive connector to form a weld, and the groove intersects with the weld. The groove is used to detect the penetration depth of the weld according to the difference in the intensity of the reflected ultrasonic signal after welding. The battery cell of the present application can achieve a full inspection of the weld part between the output electrode and the bar, improve the control over the welding quality, and does not require cutting the weld and grinding metallographic detection. With the assistance of automatic detection equipment, automatic detection can also be achieved, and the detection efficiency is high.

[0079] Please refer to Figure 1 , Figure 1 A schematic structural diagram of a vehicle 1000 provided for some embodiments of the present application. The electrical equipment may be the vehicle 1000, and the vehicle 1000 may be a fuel vehicle, a gas vehicle or a new energy vehicle. The new energy vehicle may be a pure electric vehicle, a hybrid vehicle or an extended-range vehicle, etc. A battery device 100 is provided inside the vehicle 1000, and the battery device 100 may be provided at the bottom, head or tail of the vehicle 1000. The battery device 100 may be used to power the vehicle 1000, for example, the battery device 100 may serve as an operating power source for the vehicle 1000. The vehicle 1000 may further include a controller 200 and a motor 300, and the controller 200 is used to control the battery device 100 to power the motor 300, for example, for starting, navigating and operating power requirements of the vehicle 1000 during driving.

[0080] In some embodiments of the present application, the battery device 100 can serve not only as an operating power source for the vehicle 1000 , but also as a driving power source for the vehicle 1000 , replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1000 .

[0081] Please refer to Figure 2 , Figure 2 Schematic diagram of the exploded structure of the battery device 100 provided in some embodiments of the present application. The battery device 100 includes a case 10 and a battery cell 20, and the battery cell 20 is accommodated in the case 10. The case 10 is used to provide a storage space for the battery cell 20, and the case 10 can adopt a variety of structures. In some embodiments, the case 10 may include an upper cover 11 and a case base 12, and the upper cover 11 and the case base 12 cover each other, and the upper cover 11 and the case base 12 together define a storage space for accommodating the battery cell 20. The case base 12 can be a hollow structure with one end open, and the upper cover 11 can be a plate-shaped structure. The upper cover 11 covers the open side of the case base 12, so that the upper cover 11 and the case base 12 jointly define a storage space; the upper cover 11 and the case base 12 can also be hollow structures with one side open, and the open side of the upper cover 11 covers the open side of the case base 12. Of course, the box body 10 formed by the upper cover 11 and the box base 12 can be in various shapes, such as a cylinder, a cuboid, etc.

[0082] The battery device 100 mentioned in the embodiment of the present application may include one or more battery cell assemblies for providing voltage and capacity. The battery cell assembly may include multiple battery cells 20, which are connected in series, parallel, or hybrid via a busbar.

[0083] In some embodiments, a battery cell assembly is generally formed by arranging a plurality of battery cells 20 .

[0084] As an example, the battery cell assembly may be a battery module, which is formed by arranging and fixing a plurality of battery cells 20 to form an independent module. As an example, the battery module may be formed by bundling a plurality of battery cells 20 with a cable tie.

[0085] In some embodiments, the battery device 100 may be a battery pack, which includes a case 10 and one or more battery cell assemblies, wherein the battery cell assemblies are housed in the case 10 .

[0086] As an example, the battery cell assembly may be a battery module, and the battery cell assembly may be accommodated in the box body 10 by fixing the battery module in the box body 10 .

[0087] As an example, the battery cell assembly may also be housed in the case 10 by directly fixing the plurality of battery cells 20 to the case 10 .

[0088] In the battery device 100, there may be multiple battery cells 20, which may be connected in series, in parallel, or in a hybrid connection. A hybrid connection refers to a combination of series and parallel connections among the multiple battery cells 20. The multiple battery cells 20 may be directly connected in series, in parallel, or in a hybrid connection, and then the entire battery unit 20 may be housed within the housing 10. Alternatively, the battery device 100 may comprise multiple battery cells 20 connected in series, in parallel, or in a hybrid connection to form a battery module, which is then further connected in series, in parallel, or in a hybrid connection to form a single unit and housed within the housing 10. The battery device 100 may also include other structures, such as a busbar assembly for electrically connecting the multiple battery cells 20.

[0089] Each battery cell 20 may be a secondary battery or a primary battery, and may also be a lithium-sulfur battery, a sodium-ion battery, or a magnesium-ion battery, but is not limited thereto. The battery cell 20 may be cylindrical, flat, rectangular, or in other shapes.

[0090] Reference Figure 3-Figure 6 According to some embodiments of the present application, the present application provides a battery cell 20, including a main body 1 and an output pole 2 arranged on the main body 1, the side of the output pole 2 away from the main body 1 is a welding surface 21, and a groove 3 is provided on the welding surface 21. The welding surface 21 is used to weld with a conductive connector 5 to form a weld 4. The groove 3 intersects with the weld 4, so that ultrasonic waves are emitted toward the intersection of the weld 4 and the groove 3, and the reflected signal intensity of the ultrasonic waves at the target position at different depths is detected, and the penetration depth of the weld 4 is obtained according to the reflected signal intensity.

[0091] It should be noted that the aforementioned depth is the distance from the top surface of the conductive connector 5 to the target location, along the thickness direction of the conductive connector 5. The top surface is the side of the conductive connector 5 facing away from the output electrode. The battery cell 20 includes a housing, which defines a mounting cavity for accommodating a bare cell. The housing also defines an opening communicating with the mounting cavity, and a cover plate is positioned over the opening to seal the mounting cavity. The body 1 herein refers to the housing, cover plate, and bare cell structure. The output electrode 2 of the battery cell 20 extends a distance beyond the cover plate. The output electrode 2, also known as a post, is typically two per battery cell 20: a positive output electrode and a negative output electrode, commonly referred to as the positive and negative electrodes. The output electrode 2 is used to connect to the conductive connector 5, which can be a tab. The battery device 100 also includes a sampling element, which can be a circuit board. Electrical signals from the output electrode 2 are transmitted to the sampling element via the conductive connector 5 and then to the battery management module, which monitors parameters of the battery cell 20, including but not limited to temperature, current, and voltage. At present, the connection between the output pole 2 and the conductive connector 5 is generally made by welding. Specifically, the top surface of the output pole 2 is welded to the conductive connector 5. The top surface refers to the side of the pole away from the body 1, which is the welding surface 21 mentioned in this application. The actual welding is carried out from the side of the conductive connector 5 away from the output pole 2. The output pole 2 and the conductive connector 5 will form a weld 4 by laser welding. The welding quality is generally reflected by the inspection of the weld 4. The indicators of welding quality here include at least the penetration depth of the weld 4. Before welding, there will be a gap 6 between the conductive connector 5 and the output pole 2. In the related art, the penetration depth refers to the length of the weld 4 penetrating the conductive connector 5 into the gap 6. In the above embodiment of the present application, a groove 3 is provided on the welding surface 21. The groove 3 is a recessed groove provided on the welding surface 21. The intersection of the groove 3 and the weld 4 means that there is a portion where the groove 3 and the weld 4 are combined with each other. For example, it can be that the weld 4 extends into the groove body of the groove 3, and the two are combined with each other. Of course, when the penetration depth of weld 4 is small, the projection of weld 4 on weld surface 21 may intersect with groove 3. The depth of groove 3 is called groove depth. During specific testing, the position of the ultrasonic transmitter can be adjusted so that the ultrasonic wave is emitted toward the intersection of weld 4 and groove 3. The reflected signal strength of the ultrasonic wave at target positions at different depths is then measured, and the penetration depth of weld 4 is obtained based on the reflected signal strength.

[0092] According to the principles of ultrasonic nondestructive testing, ultrasonic waves attenuate in media of varying densities, resulting in varying reflection signal intensities. Specifically, if the density difference is large, such as at a solid-gas or gas-solid interface, the ultrasonic reflection signal intensity at such an interface is high, resulting in a strong reflection signal. If the density difference is small, such as at a solid-solid interface, the ultrasonic reflection signal intensity at that depth is low, resulting in a weak reflection signal.

[0093] Specifically in the technical solution of this application, refer to Figure 8 and Figure 9 , the conductive connector 5 can be a bar sheet, and the ultrasonic detection position gradually penetrates downward from the upper surface of the bar sheet. The origin with a depth of 0 refers to the upper surface position of the bar sheet. When the depth is within the bar sheet, the density is basically the same and there is no obvious change. Therefore, the reflection signal intensity is small, which is a weak reflection signal. If the detection position is the intersection of the weld 4 and the groove 3, when there is a weld 4 on the lower surface of the bar sheet, the ultrasonic reflection signal intensity at the depth of the interface of the intersection of the weld 4 and the bar sheet and the reflection signal intensity inside the weld 4 are both small, which is a weak reflection signal. When the weld 4 has a small penetration depth, the groove 3 is not filled with the weld molten pool. There will be a solid-gas interface at the top position where the weld 4 extends into the groove 3. The reflection signal intensity here is large, which is a strong reflection signal. As for the groove depth and position of the groove 3, they can be known in advance, so the penetration depth of the weld 4 can be determined. If the penetration depth is defined as: starting from the upper surface of the conductive connector 5, along the vertical direction of the length of the top of the weld 4, a strong reflection signal appears at point C, and the reflection signal intensity at this time is as follows: Figure 8 The vertical coordinate corresponding to point C is shown in the figure. The penetration depth is as follows: Figure 8 As shown at point C1, C1 is the horizontal axis value corresponding to C, and C1 is the depth value corresponding to the strong reflection signal, that is, the penetration depth. The specific detection method can refer to the welding quality detection method described later.

[0094] In the above embodiment of the present application, a groove 3 is provided on the welding surface 21 of the output pole 2, and the weld 4 intersects with the groove 3. The ultrasonic wave can be emitted toward the intersection of the weld 4 and the groove 3 to detect the reflected signal intensity of the ultrasonic wave at the target position at different depths. The different reflected signal intensities of the ultrasonic wave in different density media are utilized to obtain the penetration depth of the weld 4 according to the reflected signal intensity, thereby realizing non-destructive detection of the weld 4. This is a non-destructive detection method, thereby realizing full inspection of the welding part of the output pole 2 and the bar, improving the control over the welding quality, and eliminating the need for cutting the weld 4 and grinding phase detection. With the assistance of automatic detection equipment, automatic detection can also be realized, and the detection efficiency is high.

[0095] In some embodiments, the number of the groove 3 is one, and both ends of the groove 3 extend to the outer edge of the welding surface 21 respectively.

[0096] The number of grooves 3 can be one, and the two ends of the groove 3 extend to the outer edge of the welding surface 21 respectively. The outer edge refers to the edge position of the outside. The weld 4 formed after laser welding is generally annular. The groove 3 can be a straight groove, a curved groove or any other shape. The two ends of the groove 3 are extended to the edge of the welding surface 21 to ensure that the groove 3 can intersect with the weld 4, which is convenient for the subsequent detection of the penetration depth of the weld 4 with the help of the groove 3.

[0097] By extending both ends of the groove 3 to the outer edges of the welding surface 21 , it is ensured that the weld 4 and the groove 3 can intersect, which is convenient for subsequent penetration detection.

[0098] To show the structure of the groove 3, please refer to Figure 5 , Figure 5 for Figure 4 Schematic diagram of the structure of the unwelded conductive connector 5 on the middle output pole 2. In some embodiments, there are multiple grooves 3, each groove 3 intersects with the weld 4, and both ends of each groove 3 extend to the outer edge of the welding surface 21.

[0099] If the weld penetration is large, the groove 3 is completely filled with the weld pool, and the ultrasonic wave does not reflect a strong signal until it detects the bottom of the groove 3. Therefore, it can be determined that the weld penetration has at least reached the bottom of the groove 3. Filling the bottom of the groove 3 also fills at least the gap 6 between the weld surface 21 and the blade, which can also be used to determine the weld quality. However, this can only qualitatively detect the value of the penetration, but cannot quantitatively obtain the specific value of the penetration. For some scenarios where quantitative penetration data is required, multiple grooves 3 can be set on the weld surface 21, and the groove depths of the multiple grooves 3 are different, which can also be said to be set in a gradient.

[0100] The depth of each groove 3 can be obtained in advance, either by recording it when the groove 3 is made or by testing it before welding. The specific detection method is to adjust the position of the ultrasonic transmitter so that the ultrasonic wave is emitted toward the intersection of the weld 4 and the groove 3 with the smallest groove depth, and then detect the penetration depth of the target position at different depths. If a strong reflection signal appears after the depth reaches the output pole 2, the penetration depth of the weld 4 can be obtained by recording the depth corresponding to this strong reflection signal. If no strong reflection signal appears when the depth reaches the bottom of the groove 3, it means that the welding pool has filled the groove 3. It can be confirmed that the penetration depth must be greater than or equal to the depth of the groove 3, but the specific value of the penetration depth cannot be quantitatively confirmed.

[0101] Therefore, the ultrasonic transmitter can be moved to the groove 3 with the second smallest groove depth, and the ultrasonic wave can be emitted at the intersection of the groove 3 and the weld 4. If a strong reflection signal appears after the depth exceeds the output electrode 2, it means that the weld 4 has extended into the groove 3 but has not completely filled the groove 3. The quantitative value of the penetration depth can be determined based on the depth of the strong reflection signal. Of course, if no strong reflection signal appears, the next groove 3 with a larger groove depth can be selected for testing.

[0102] By setting multiple grooves 3 of different depths and adjusting the position of the ultrasonic transmitter, the ultrasonic wave is emitted in sequence toward the intersections of the weld 4 and the multiple grooves 3 in a preset emission order. This can be used to quantitatively detect the penetration depth of the weld 4, and can detect welds 4 with different penetration depths, thereby improving the applicability of the welding quality detection method.

[0103] In some embodiments, the depth of each groove 3 is set in a gradient.

[0104] Theoretically, as long as the groove depths of multiple grooves 3 are not exactly the same, the effect of quantitative detection of the grooves 3 can be improved. However, in order to expand the detection range of the penetration depth of the weld 4, the depths of the grooves 3 are different and are set in a gradient.

[0105] By setting the groove depth of each groove 3 in a gradient, the detection range of the penetration depth of the weld 4 can be expanded.

[0106] In some embodiments, the welding surface 21 is a circular surface, and the shape of the weld 4 is annular; or,

[0107] The welding surface 21 is a rectangular surface, and the shape of the weld 4 is a rectangle.

[0108] It should be noted that the shape of the welding surface 21 is not specifically limited in this application and can be a circular surface, a rectangular surface, or other shapes, and can be a regular shape or an irregular shape. Correspondingly, the shape of the weld 4 is also not specifically limited, as long as the weld 4 can intersect with the groove 3. In a specific embodiment, when the welding surface 21 is a circular surface or a rectangular surface, each groove 3 passes through the center point of the welding surface 21, and the weld 4 is correspondingly circular or rectangular, which facilitates the intersection of the groove 3 and the weld 4.

[0109] By setting the welding surface 21 and the weld 4 to have a matching shape, the weld 4 and the groove 3 are easily intersected, and the detection of the penetration depth is convenient.

[0110] In the above-mentioned embodiment of the present application, the battery cell 20 includes a main body 1 and an output pole 2 arranged on the main body 1, and the side of the output pole 2 away from the main body 1 is a welding surface 21, and a groove 3 is provided on the welding surface 21. The welding surface 21 is used to weld with the conductive connector 5 to form a weld 4, wherein the number of grooves 3 is one or more. When the number of grooves 3 is multiple, the groove depth of each groove 3 is set in a gradient, and the two ends of the groove 3 extend to the outer edge of the welding surface 21 respectively, and the groove 3 intersects with the weld 4. The groove 3 is used to detect the penetration depth of the weld 4 according to the difference in the intensity of the reflected signal of the ultrasonic wave after welding. By setting a groove 3 on the welding surface 21 of the output pole 2, the weld 4 intersects with the groove 3. The ultrasonic wave can be emitted toward the intersection of the weld 4 and the groove 3 to detect the reflected signal intensity of the ultrasonic wave at the target position at different depths. The different reflected signal intensities of the ultrasonic wave in media of different densities are utilized to obtain the penetration depth of the weld 4 according to the reflected signal intensity, thereby realizing non-destructive detection of the weld 4. This is a non-destructive detection method, thereby realizing full inspection of the welding part of the output pole 2 and the bar, improving the control over the welding quality, and eliminating the need to cut the weld 4 and perform metallographic phase detection. With the assistance of automatic detection equipment, automatic detection can also be realized, and the detection efficiency is high.

[0111] Reference Figure 7According to some embodiments of the present application, a welding quality detection method is provided for detecting the weld 4 between the output electrode 2 and the conductive connector 5 of the battery cell 20. Specifically, the output electrode 2 is provided with a welding surface 21 on the side of the output electrode 2 away from the body 1. The welding surface 21 is provided with a groove 3. The welding surface 21 is used to weld with the conductive connector 5 to form the weld 4. The groove 3 intersects the weld 4. Ultrasonic waves are emitted toward the intersection of the weld 4 and the groove 3. The reflected signal intensity of the ultrasonic waves at target positions at different depths is detected, and the penetration depth of the weld 4 is obtained based on the reflected signal intensity. The output electrode 2 is used to connect to the conductive connector 5, which can be a bar. The battery device 100 also includes a sampling component, which can be a circuit board. The bar transmits the electrical signal from the output electrode 2 to the sampling component and finally to the battery management module to detect parameters of the battery cell 20, including but not limited to information such as the temperature and current of the battery cell 20. Currently, the connection between the output pole 2 and the conductive connector 5 is generally achieved by welding. Specifically, the top surface of the output pole 2 is welded to the conductive connector 5. The top surface refers to the side of the output pole 2 away from the body 1, which is referred to as the welding surface 21 in this article. The actual welding is performed from the side of the conductive connector 5 away from the output pole 2. The output pole 2 and the conductive connector 5 are laser welded to form a weld 4. The welding quality is generally reflected by testing the weld 4. The welding quality indicator here includes at least the penetration depth of the weld 4. Before welding, there is a gap 6 between the conductive connector 5 and the output pole 2. In related art, the penetration depth refers to the length of the weld 4 that penetrates the conductive connector 5 and extends into the gap 6. In the above-described embodiment of the present application, a groove 3 is provided on the welding surface 21. The groove 3 is a recessed groove provided in the welding surface 21. The weld 4 may extend into the groove 3. The penetration depth in the present application refers to the length of the weld 4 penetrating the conductive connector 5 and extending into the gap 6 or the groove 3. The intersection of the groove 3 and the weld 4 refers to the portion where the groove 3 and the weld 4 are mutually connected. For example, the weld 4 may extend into the groove body of the groove 3, and the two may be connected. Of course, when the penetration depth of the weld 4 is small, it is also possible that the projection of the weld 4 on the welding surface 21 intersects the groove 3.

[0112] Specifically, the welding quality detection method includes:

[0113] S100 , adjusting the position of the ultrasonic transmitter head so that the ultrasonic wave is emitted toward the intersection of the weld 4 and the groove 3 .

[0114] The ultrasonic transmitter is used to emit ultrasonic waves to weld the conductive connector 5 to the welding surface 21 to form the weld 4. The groove 3 is pre-set on the output pole 2, that is, it is completed when the battery cell 20 is manufactured. Before welding the conductive connector 5 to the output pole 2, the position information of the groove 3 is first obtained. After the welding is completed, the contour information of the weld 4 can be obtained. The position information of the groove 3 and the outer contour of the weld 4 can be used to determine the intersection of the weld 4 and the groove 3. The ultrasonic transmitter is aligned with the intersection of the weld 4 and the groove 3 so that the ultrasonic detection position is in the area where the weld 4 and the groove 3 intersect.

[0115] S200, detecting the reflected signal intensity of the ultrasonic wave at target positions at different depths;

[0116] The depth is the distance from the upper surface of the conductive connector 5 to the target position in the thickness direction of the conductive connector 5 , where the upper surface is the side of the conductive connector 5 facing away from the output pole 2 .

[0117] Specifically, the ultrasonic reflection signal strength at different depths can be detected starting from the upper surface of the conductive connector 5 and gradually moving downward. The upper surface refers to the side facing the ultrasonic transmitter, which is also the side of the conductive connector 5 facing away from the output electrode 2. Starting from the upper surface of the conductive connector 5 at a depth of 0, the ultrasonic reflection signal strength at different depths can be gradually detected downward along the vertical direction. In this way, the reflection signal strength at each depth can be obtained, and a trend chart of the reflection signal strength versus depth can be automatically obtained by a computer.

[0118] S300: Obtain the penetration depth of the weld 4 according to the reflected signal intensity.

[0119] There are various definitions of penetration in the related art. Penetration can be defined as the length measured vertically from the top surface of the conductive connector 5 to the top of the weld 4, or as the length measured vertically from the bottom surface of the conductive connector 5. The top of the weld 4 here refers to the end of the weld 4 away from the top surface of the conductive connector 5. The difference between these two definitions is the thickness of the conductive connector 5 and is not substantial. In this application, penetration is defined as the length measured vertically from the top surface of the conductive connector 5 to the top of the weld 4.

[0120] This utilizes the principle of ultrasonic nondestructive testing: ultrasonic waves attenuate in media of varying densities, resulting in varying reflection signal intensities. Specifically, if the density difference is large, such as at a solid-gas or gas-solid interface, the ultrasonic reflection signal at such an interface will be strong, resulting in a strong reflection signal. If the density difference is small, such as at a solid-solid interface, the ultrasonic reflection signal at that depth will be weak, resulting in a weak reflection signal.

[0121] Specifically in the technical solution of this application, refer to Figure 8 and Figure 9 , the conductive connector 5 can be a bar, and the ultrasonic detection position gradually penetrates downward from the upper surface of the bar. When the depth is inside the bar, the seal is basically the same and there is no obvious change, so the reflection signal intensity is small, which is a weak reflection signal. If the detection position is the intersection of the weld 4 and the groove 3, when there is a weld 4 on the lower surface of the bar, the ultrasonic reflection signal intensity at the depth of the interface of the intersection of the weld 4 and the bar and the reflection signal intensity inside the weld 4 are small, which is a weak reflection signal. When the weld 4 has a small penetration depth, the groove 3 is not filled with the weld molten pool, and there will be a solid-gas interface at the top position where the weld 4 extends into the groove 3. The reflection signal intensity here is large, which is a strong reflection signal. As for the groove depth and position of the groove 3, they can be known in advance, so the penetration depth of the weld 4 can be determined. If the penetration depth is defined as: starting from the upper surface of the conductive connector 5, the length of the top of the weld 4 along the vertical direction, the area where the strong reflection signal appears is at point C, and the penetration depth is as follows: Figure 8 As shown at point C1, C1 is the horizontal coordinate value corresponding to C, and C1 is the depth value corresponding to the strong reflection signal. The depth value can reflect the penetration depth of the weld 4.

[0122] Of course, if the welding penetration is large, the depth of groove 3 is completely filled with the welding molten pool, and the ultrasonic wave will not strongly reflect the signal until the bottom of groove 3 is detected. Therefore, it can be determined that the welding penetration has at least reached the bottom of groove 3. Filling the bottom of groove 3 means at least filling the gap 6 between the welding surface 21 and the bar, which can also be used to determine that the welding quality is good.

[0123] In the above-mentioned embodiment of the present application, by emitting ultrasonic waves toward the intersection of the weld 4 and the groove 3, detecting the reflected signal intensity of the ultrasonic waves at target positions of different depths, and utilizing the different reflected signal intensities of ultrasonic waves in media of different densities, the penetration depth of the weld 4 is obtained according to the reflected signal intensity, thereby achieving non-destructive testing of the weld 4. This is a non-destructive testing method, thereby achieving full inspection of the welding part of the output pole 2 and the bar, improving the control over the welding quality, and eliminating the need to cut the weld 4 and perform metallographic phase testing. With the assistance of automatic testing equipment, automatic testing can also be achieved, and the detection efficiency is high.

[0124] Reference Figure 9 In some embodiments, there are multiple grooves 3, and the groove depths of the multiple grooves 3 are set in a gradient; the step S100 includes:

[0125] S101, adjust the position of the ultrasonic transmitter so that the ultrasonic wave is sequentially emitted toward the intersections of the weld 4 and the plurality of grooves 3 in a preset emission sequence; the preset emission sequence is: the order in which the groove depth values ​​of the plurality of grooves 3 are arranged from small to large.

[0126] As mentioned above, when the welding penetration is small, Figure 10 The second sub-slit 42 does not fill the groove 3 of the output pole 2. The penetration depth can be obtained by a single test, such as Figure 11 A strong reflection signal appears at point D, and the corresponding horizontal coordinate D1 is the penetration depth of the second sub-seam 42. However, when the penetration depth of the weld 4 is large, the depth of the groove 3 is completely filled with the weld pool, as shown in Figure 2. Figure 10 When the first sub-slit 41 extends into the groove 3 of the output electrode 2 and fills the weld pool, the ultrasonic wave will not reflect a strong signal until it detects the bottom of the groove 3. This also allows us to determine that the weld penetration has at least reached the bottom of the groove 3. In other words, we can know that the penetration is definitely greater than a numerical value, but we cannot quantitatively obtain the depth value of the penetration. Therefore, in some scenarios where quantitative penetration data is required, multiple grooves 3 can be provided on the welding surface 21, and the groove depths of the multiple grooves 3 are different, which can also be said to be arranged in a gradient.

[0127] The depth of each groove 3 can be obtained in advance, either by recording it when the groove 3 is made, or by testing it before welding. The specific detection method is to adjust the position of the ultrasonic transmitter head so that the ultrasonic wave is emitted toward the intersection of the weld 4 and the groove 3 with the smallest groove depth, and then detect the penetration depth of the target position at different depths. If a strong reflection signal appears after the depth reaches the output pole 2, the penetration depth of the weld 4 can be obtained by recording the depth corresponding to the strong reflection signal. If no strong reflection signal appears when the depth reaches the bottom of the groove 3, it means that the welding pool has filled the groove 3. It can be confirmed that the penetration depth must be greater than the depth of the groove 3, but the specific value of the penetration depth cannot be confirmed. Figure 12 As shown in point F, the groove 3 with a depth of F1 in the figure is filled, but no strong reflection signal appears, indicating that the weld 4 has filled the molten pool. The penetration depth of the weld 4 cannot be quantitatively detected by the groove 3 with a depth of F1 alone.

[0128] Therefore, the ultrasonic transmitter can be moved to the groove 3 with the second smallest groove depth, and the ultrasonic wave can be emitted at the intersection of the groove 3 and the weld 4. If a strong reflection signal appears after the depth exceeds the output electrode 2, it means that the weld 4 has extended into the groove 3 and has not completely filled the groove 3. Therefore, the quantitative value of the penetration depth can be determined according to the depth of the strong reflection signal, such as Figure 12 As shown at point E, the coordinate value of point E1 represents the penetration depth, and E1 is the horizontal coordinate value of point E. Of course, if there is still no strong reflection signal, the next groove 3 with a larger groove depth is selected for detection.

[0129] It should also be noted that although this embodiment defines the preset emission order as the order in which the groove depth values ​​of the multiple grooves 3 are arranged from smallest to largest, in actual detection, the detection of the grooves 3 can be performed in a different order. If the approximate range of the penetration depth of the weld 4 can be estimated, the detection can be started with the groove 3 that is close to the penetration depth range, further improving the detection efficiency. In addition, the depth of some of the multiple grooves 3 can be set to the same to detect the penetration depth of the weld 4 at different cross-sectional locations at the same depth.

[0130] By setting multiple grooves 3 of different depths and adjusting the position of the ultrasonic transmitter, the ultrasonic wave is emitted in sequence toward the intersections of the weld 4 and the multiple grooves 3 in a preset emission order. This can be used to quantitatively detect the penetration depth of the weld 4, and can detect welds 4 with different penetration depths, thereby improving the scope of application of the weld 4 quality detection method.

[0131] Reference Figure 13 In some embodiments, the step of S200 further includes:

[0132] S210 , obtaining the reflected signal strength of the ultrasonic wave at different depths in descending order of depth values.

[0133] The depth value here refers to the depth of the position where the ultrasonic reflection signal intensity is detected, that is, the vertical distance from the upper surface of the conductive connector 5 to the target position. The greater the depth, the farther the distance from the upper surface of the conductive connector 5. The ultrasonic reflection signal intensity is obtained in order from small to large depth values. This is convenient for operation and data recording, and a trend diagram of the reflection signal intensity changing with depth is obtained.

[0134] By setting the depth values ​​in ascending order to obtain the reflected signal strength of the ultrasonic wave at different depths, it is convenient to operate and also convenient to obtain the trend change graph of the reflected signal strength change.

[0135] Reference Figure 14 In some embodiments, the step of S200 includes:

[0136] S201, if the reflected signal strength is greater than or equal to a preset threshold, it is defined as a strong reflected signal;

[0137] If the reflected signal strength is less than the preset threshold, it is defined as a weak reflected signal;

[0138] The specific preset threshold here can be a certain ultrasonic reflection intensity value. This value can be obtained based on the initial ultrasonic intensity emitted by the transmitter and can be set by those skilled in the art according to actual needs. For example, a strong reflection signal can be defined as 5% or more of the initial ultrasonic intensity, while a weak reflection signal can be defined as less than 5% of the initial ultrasonic intensity. If the reflection signal appears as a horizontal line in the reflection signal intensity-depth trend change graph,

[0139] The steps of S300 include:

[0140] S301 , when the reflection signal strength changes from a weak reflection signal to a strong reflection signal, the depth value at this time is recorded, and the depth value is the penetration depth of the weld 4 .

[0141] When the reflected signal intensity is less than 5% of the initial ultrasonic intensity, a horizontal line is shown in the reflected signal intensity-depth trend change diagram. When the transmitted signal intensity is a strong reflected signal, a leap will appear, forming a peak point. The vertical line corresponding to this peak point is the depth value corresponding to the solid-gas interface. The depth value can be used to obtain the weld depth. Figure 11 Point D and Figure 12 Point E in .

[0142] By defining the numerical ranges of strong reflection signals and weak reflection signals, the penetration depth of the weld 4 can be directly read from the reflection signal intensity-depth trend diagram, which is very convenient to operate.

[0143] Reference Figure 15 In some embodiments, the welding quality detection method further includes:

[0144] S400 , detecting the reflected signal intensity of the ultrasonic wave in each area at a preset depth position; wherein the preset depth position is the depth position where the lower surface of the conductive connecting member 5 is located.

[0145] Combined with reference Figure 16 and Figure 17 , Figure 16 R indicates that there is a weak reflection signal in this area, indicating that there is a weld at this location, and Q indicates that there is a strong reflection signal in this area. Specifically for this solution, before welding, there is a certain gap 6 between the bar and the output pole 2. If the weld 4 can penetrate the bar and the pole, then the interface between the bar and the pole is a solid-solid interface with a small density difference. The intensity of the ultrasonic reflection signal at this depth is weak, which is a weak reflection signal, indicating that there is a weld 4 here. However, if the detection position is at the solid-gas interface or the gas-solid interface, the density difference is large, and the intensity of the ultrasonic reflection signal at such an interface is large, which is a strong reflection signal, proving that there is no weld 4 here.

[0146] S500 , obtaining the outer contour of the weld 4 at a preset depth position according to the reflected signal intensity.

[0147] By statistically collecting the weak reflection signals and strong reflection signals in each area, the outer contour of the weld 4 at a preset depth can be obtained based on the statistical information of the weak reflection signal area.

[0148] S600: Obtain the weld width of the weld 4 according to the outer contour.

[0149] By applying the algorithm to the outer contour, the weld area can be calculated, and the weld width data can be obtained based on the weld area. For example, the weld width of weld 4 can be obtained by dividing the weld area by the length of weld 4. If weld 4 is generally a circular weld, the length of weld 4 is the circumference of the circular weld, specifically the center circumference of the circular weld.

[0150] In addition, it should be noted that the weld width detection of the weld 4 can be performed before or after the weld depth detection. This application does not make any specific restrictions on this, and those skilled in the art can set it according to actual needs.

[0151] By detecting the reflected signal intensity of the ultrasonic wave in each area at the preset depth position, the outer contour of the weld 4 at the preset depth position is obtained according to the reflected signal intensity, and the weld width of the weld 4 is obtained according to the outer contour. The weld width data of the weld 4 can be obtained through non-destructive testing.

[0152] According to some embodiments of the present application, a welding quality inspection method is provided for inspecting the weld 4 between the output terminal 2 and the conductive connector 5 of the aforementioned battery cell 20. The welding quality inspection method comprises: adjusting the position of an ultrasonic transmitter so that ultrasonic waves are sequentially emitted toward each intersection of the weld 4 and the plurality of grooves 3 in a predetermined transmission sequence; the predetermined transmission sequence is: arranging the plurality of grooves 3 in ascending order of depth; sequentially obtaining the reflected signal strength of the ultrasonic waves at different depths in ascending order of depth; if the reflected signal strength is greater than or equal to a predetermined threshold, it is defined as a strong reflected signal; if the reflected signal strength is less than the predetermined threshold, it is defined as a weak reflected signal; when the reflected signal strength changes from a weak reflected signal to a strong reflected signal, recording the depth value at that time, which is the penetration depth of the weld 4. The welding quality inspection method further comprises: detecting the reflected signal strength of the ultrasonic waves at each area at a predetermined depth; obtaining the outer contour of the weld 4 at the predetermined depth based on the reflected signal strength; and obtaining the weld width of the weld 4 based on the outer contour; wherein the predetermined depth is the depth at which the lower surface of the conductive connector 5 is located. By using the above detection method, the penetration depth and width information of the weld 4 can be non-destructively detected, thereby achieving full inspection and improving inspection efficiency.

[0153] According to some embodiments of the present application, the present application provides a battery device 100, including a box body 10, multiple battery cells 20, a conductive connector 5, a sampling piece and a battery management module. The box body 10 is provided with a accommodating cavity, the battery cell 20 is the above-mentioned battery cell 20, the conductive connector 5 is welded to the welding surface 21 of the battery cell 20 to form a weld 4, and the sampling piece is electrically connected to the conductive connector 5 and the battery management module.

[0154] As mentioned above, the conductive connecting part 5 can be a bar, the battery cell 20 is provided with an output pole 2, and the sampling part can be a circuit board. The bar electrically connects the output pole 2 and the circuit board. The electrical signal of the battery cell 20 obtained from the output pole 2 is transmitted to the battery management module through the circuit board to realize monitoring of the battery cell 20.

[0155] The output pole 2 and the sampling piece are electrically connected through the conductive connector 5, and the electrical signal is transmitted to the battery management module through the sampling piece to realize the monitoring of the battery cell 20 signal. At the same time, the battery cell 20 used can perform ultrasonic non-destructive testing and efficiently detect the penetration depth and width of the weld 4.

[0156] In some embodiments, the weld seam 4 is annular in shape and intersects the groove 3 at multiple locations. The annular weld seam 4 can intersect with a single groove 3 at multiple locations. For example, if the groove 3 is a straight line, there can be two intersections. When there are multiple grooves 3, there are more intersections, and the ultrasonic reflection signal strength is detected at these intersections. This allows for multiple detection locations and improves detection convenience.

[0157] By setting the weld 4 as an annular weld and intersecting the groove 3 at multiple locations, the convenience of detection can be improved.

[0158] According to some embodiments of the present application, an electric device is provided. The electric device includes a device body and the aforementioned battery device 100, with the battery device 100 disposed within the device body. The electric device may be a vehicle 1000. Because the electric device includes any of the technical solutions of all of the aforementioned embodiments, it possesses at least all of the beneficial effects brought about by any of the aforementioned technical solutions, and therefore, no further details are given here.

[0159] The above description is merely an optional embodiment of the present application and does not limit the patent scope of the present application. Any equivalent structural transformation made by using the contents of the present application specification and drawings under the application concept of the present application, or directly / indirectly applied in other related technical fields, is included in the patent protection scope of the present application.

Claims

1. A battery cell, characterized in that: The invention comprises a body and an output electrode provided on the body, wherein a side of the output electrode away from the body is a welding surface, a groove is provided on the welding surface, and two ends of the groove respectively extend to the outer edge of the welding surface; welding is performed from a side of the conductive connector away from the output electrode, the welding surface is used to weld with the conductive connector to form a weld, the weld is circular or rectangular, the groove intersects with the weld, and the weld extends into the groove body of the groove; when the weld penetration is small, the groove depth is not filled by the weld, and a solid-gas interface exists at the top position of the weld extending into the groove, so that ultrasonic waves are emitted toward the intersection of the weld and the groove, and the reflected signal intensity of the ultrasonic waves at target positions at different depths is detected, and the weld penetration is obtained according to the depth value when the reflected signal intensity changes from a weak reflected signal to a strong reflected signal; The depth is the distance from the upper surface of the conductive connector downward to the target position in the thickness direction of the conductive connector.

2. The battery cell according to claim 1, wherein: The number of the groove is one.

3. The battery cell according to claim 1, wherein: There are multiple grooves, each of which intersects with the weld, and both ends of each groove extend to the outer edge of the welding surface.

4. The battery cell according to claim 3, characterized in that The depth of each groove is set in a gradient.

5. A welding quality inspection method, used to inspect the weld between the output electrode and the conductive connector of the battery cell according to claim 1, characterized in that: The welding quality detection method comprises: Adjust the position of the ultrasonic transmitter so that the ultrasonic wave is emitted toward the intersection of the weld and the groove; detecting the reflected signal intensity of the ultrasonic wave at target positions at different depths; The depth is the distance from the upper surface of the conductive connector to the target position in the thickness direction of the conductive connector, where the upper surface is the side of the conductive connector facing away from the output electrode. If the reflected signal strength is greater than or equal to the preset threshold, it is defined as a strong reflected signal; If the reflected signal strength is less than the preset threshold, it is defined as a weak reflected signal; When the intensity of the reflection signal changes from a weak reflection signal to a strong reflection signal, the depth value at this time is recorded, and the depth value is the penetration depth of the weld.

6. The welding quality detection method according to claim 5, characterized in that: There are multiple grooves, and the depths of the multiple grooves are arranged in a gradient. The step of adjusting the position of the ultrasonic transmitter so that the ultrasonic wave is emitted toward the intersection of the weld and the groove comprises: Adjust the position of the ultrasonic transmitter so that the ultrasonic wave is emitted in sequence toward the intersections of the weld and the multiple grooves according to the preset emission order; The preset emission sequence is: an order in which the groove depth values ​​of the plurality of grooves are arranged from small to large.

7. The welding quality detection method according to claim 6, characterized in that: The step of detecting the reflected signal strength of the ultrasonic wave at target positions at different depths includes: The reflected signal intensity of the ultrasonic wave at different depths is obtained in order from small to large depth values.

8. The welding quality detection method according to claim 5, characterized in that: The welding quality detection method further comprises: Detecting the reflected signal intensity of the ultrasonic wave in each area at a preset depth position; wherein the preset depth position is the depth position of the lower surface of the conductive connector; Determine the outer contour of the weld at a preset depth based on the intensity of the reflected signal; The weld width of the weld is obtained according to the outer contour.

9. A battery device, characterized in that: include: A box body, wherein the box body is provided with a receiving cavity; A plurality of battery cells, wherein the battery cells are the battery cells according to any one of claims 1 to 4; A conductive connector, wherein the conductive connector is welded to a welding surface of the output electrode of the battery cell to form a weld; Sampling pieces; The sampling component is electrically connected to the battery management module.

10. The battery device according to claim 9, characterized in that The weld is annular in shape and intersects with the groove at multiple locations.

11. An electrical device, characterized in that: The electrical equipment includes an equipment body and the battery device according to claim 9 or 10, and the battery device is arranged in the equipment body.

Images