Battery cell, battery device, electrical equipment and welding quality detection method

Abstract

The present application discloses a battery cell, a battery device, an electrical equipment and a welding quality detection method, relating to the technical field of battery production detection. The battery cell includes a body and an output electrode. The output electrode includes a top surface, a bottom surface oppositely arranged to the top surface, and a sidewall connecting the top surface and the bottom surface. The bottom surface is connected to the body. An air flow channel is arranged inside the output electrode. Two ends of the air flow channel are provided with a first opening and a second opening. The first opening is arranged on the top surface, and the second opening is arranged on the sidewall. The top surface is used for welding with a conductive connection member, and the formed weld seam extends into the air flow channel. The air flow channel is used for introducing a gas, so as to obtain the penetration depth of the weld seam by detecting gas parameters. By using the battery cell of the present application, full inspection of the welding part between the output electrode and the tab can be realized, the control strength of the welding quality can be improved, and there is no need to cut the weld seam and grind the metallographic inspection. With the assistance of an automatic detection device, 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 and detection, and particularly relates to a battery cell, a battery device, an electrical equipment, and a welding quality detection method. Background Art

[0002] During the production process of power batteries, it is necessary to use a laser to weld a conductive connecting piece and an output pole together. After welding, a weld seam is formed. The conductive connecting piece generally refers to a tab. If the welded joint fails, it may cause insufficient local strength of the battery device, which may lead to abnormal sampling signals and even a risk of overheating and catching fire. Therefore, it is necessary to control the welding quality between the conductive connecting piece and the output pole. However, limited by the detection method, the current detection method can only perform sampling inspection, and the detection efficiency is low. Summary of the Invention

[0003] The main purpose of the present application is to propose a battery cell, a battery device, an electrical equipment, and a welding quality detection method, aiming to at least improve the technical problem that the welding quality detection of the output pole and the conductive connecting piece in the battery device can only be sampled and the detection efficiency is low.

[0004] According to some embodiments of the present application, the present application provides a battery cell, including a body and an output pole. The output pole includes a top surface, a bottom surface opposite to the top surface, and a sidewall connecting the top surface and the bottom surface. The bottom surface is connected to the body. An air flow channel is provided inside the output pole. Two ends of the air flow channel are provided with a first opening and a second opening. The first opening is provided on the top surface, and the second opening is provided on the sidewall. The top surface is used for welding with a conductive connecting piece, and the formed weld seam extends into the air flow channel. The air flow channel is used for introducing a gas to obtain the penetration depth of the weld seam by detecting gas parameters.

[0005] By providing an air flow channel inside the output pole, after welding with the conductive connecting piece, a gas is introduced from the first opening on the top surface, and the penetration depth of the weld seam can be obtained according to the detected gas pressure or gas flow rate. This embodiment performs non-destructive testing by introducing a gas into the air flow channel, which is a non-destructive testing method. Thus, a full inspection of the welded part between the output pole and the tab can be realized, the control strength of the welding quality can be improved, and there is no need to cut the weld seam and grind the metallographic inspection. With the assistance of an automatic detection device, automatic detection can also be realized, and the detection efficiency is high.

[0006] In some embodiments, the air flow channel includes a first sub-channel and a second sub-channel that are interconnected. The first opening is provided at one end of the second sub-channel away from the first sub-channel, and the second opening is provided at one end of the first sub-channel away from the second sub-channel. The first sub-channel is a horizontal sub-channel with a constant cross-section, and the central axis of the first sub-channel is perpendicular to the central axis of the output pole.

[0007] A first sub-channel with a horizontal and constant cross-section is provided, and the weld seam extends into the first sub-channel, facilitating the calculation of the penetration depth of the weld seam based on the measured gas parameters.

[0008] In some embodiments, a plane perpendicular to the central axis of the first sub-channel is defined as the cross-section of the first sub-channel. The projection dimension of the cross-section of the first sub-channel on the plane where the top surface is located is defined as the width of the first sub-channel, and the dimension of the first sub-channel along the central axis direction of the output pole is defined as the height of the first sub-channel. Then: the height of the first sub-channel is greater than or equal to the width of the first sub-channel.

[0009] By setting the height of the first sub-channel to be greater than or equal to the width of the first sub-channel, designing the height of the first sub-channel to be larger is beneficial to increasing the measurement range of the penetration depth, and designing the width to be smaller is beneficial to reducing the risk of output pole collapse and improving the measurement accuracy.

[0010] In some embodiments, the cross-section of the first sub-channel is an ellipse, the major axis of the ellipse is parallel to the central axis of the output pole, the height of the first sub-channel is equal to the major axis dimension of the ellipse, and the width of the first sub-channel is equal to the minor axis dimension of the ellipse.

[0011] By setting the height of the first sub-channel to be equal to the major axis dimension of the ellipse and the width of the first sub-channel to be equal to the minor axis dimension of the ellipse, the height of the first sub-channel can be increased as much as possible, which is beneficial to increasing the measurement range of the penetration depth; the width of the first sub-channel can be reduced as much as possible, which is beneficial to reducing the risk of output pole collapse and improving the measurement accuracy.

[0012] In some embodiments, the cross-section of the first sub-channel is a circle, the height of the first sub-channel is equal to the width of the first sub-channel, and both are the same as the diameter of the circle.

[0013] By setting the first sub-channel as a cylindrical channel, it is not only more convenient to manufacture, but also has a suitable width and height, and can also meet the detection requirements.

[0014] In some embodiments, the width of the first sub-channel is defined as d; where 0 < d ≤ 0.3 mm.

[0015] By setting the width of the appropriate first sub-channel, the weld can be made to fill the passing position as much as possible, that is, there will be no air flow that can pass above the position reached by the weld, improving the accuracy of detecting the penetration depth.

[0016] In some embodiments, the cross-sectional area of the first sub-channel is the same as the cross-sectional area of the second sub-channel; or, the shapes and sizes of the first sub-channel and the second sub-channel are both the same.

[0017] By setting the cross-sectional area of the first sub-channel to be the same as the cross-sectional area of the second sub-channel; or, the shapes and sizes of the first sub-channel and the second sub-channel are both the same, the calculation steps for measuring and obtaining the penetration depth are more convenient.

[0018] In some embodiments, there are multiple air flow channels, and the multiple air flow channels are isolated from each other. The first openings of the multiple air flow channels are distributed at intervals on the top surface, and the second openings of the multiple air flow channels are distributed at intervals on the side wall.

[0019] By setting multiple air flow channels and the weld extending into at least part of the air flow channels, multiple penetration depth values can be obtained, and the measurement results are more accurate.

[0020] In some embodiments, the distance from the top of the first sub-channel to the top surface is defined as the depth of the first sub-channel, and the depths of the multiple first sub-channels are not completely the same.

[0021] By setting the depths of the multiple first sub-channels to be not completely the same, it can be applicable to the measurement of welds with different penetration depths, improving the measurement range of the weld penetration depth.

[0022] In some embodiments, the depths of the multiple first sub-channels are set in a gradient.

[0023] By setting the depths of the multiple first sub-channels to be in a gradient, it can be applicable to the measurement of welds with different penetration depths, improving the measurement range of the weld penetration depth.

[0024] In some embodiments, the top surface is a circular surface and the shape of the weld is an annular shape; or,

[0025] The top surface is a rectangular surface and the shape of the weld is a rectangle.

[0026] By setting the top surface and the weld to be in a matching shape, it is convenient for the weld to extend into the air flow channel.

[0027] In some embodiments, the first opening is an air inlet and the second opening is an air outlet; or,

[0028] The first opening is an air outlet, and the second opening is an air inlet.

[0029] By setting the first opening as the air inlet or the air outlet, and correspondingly setting the second opening as the air outlet or the air inlet, it can correspond to the actual application scenario.

[0030] According to some embodiments of the present application, the present application provides a welding quality detection method for detecting a weld formed by welding an output electrode of a conductive connection member to a battery cell described above. The conductive connection member is provided with a through hole communicating with the first opening, and the weld is spaced from the first opening. The welding quality detection method includes:

[0031] Introduce gas into the through hole so that the gas enters the air flow channel from the first opening;

[0032] Detect the gas parameters in the air flow channel, and obtain the penetration depth of the weld according to the gas parameters.

[0033] By setting to introduce gas into the through hole so that the gas enters the air flow channel from the first opening, detecting the gas parameters in the air flow channel, and obtaining the penetration depth of the weld according to the gas parameters. This embodiment performs non-destructive detection by introducing gas into the air flow channel, which is a non-destructive detection method. Thus, it can achieve full inspection of the welded part of the output electrode and the tab, improve the control of welding quality, and does not require cutting the weld and grinding for metallographic inspection. With the assistance of automatic detection equipment, it can also achieve automatic detection with high detection efficiency.

[0034] In some embodiments, the gas parameters include the pressure of the gas. The step of detecting the gas parameters in the air flow channel and obtaining the penetration depth of the weld according to the gas parameters includes:

[0035] Detect the pressure of the gas at the first opening, and obtain the penetration depth of the weld according to the pressure, the initial pressure, and the cross-sectional area of the first sub-channel;

[0036] Wherein, the initial pressure is the pressure measured at the first opening when the output electrode and the conductive connection member are not welded, and the cross-sectional area of the first sub-channel is the cross-sectional area of the first sub-channel when the output electrode and the conductive connection member are not welded.

[0037] By detecting the pressure of the gas at the first opening and obtaining the penetration depth of the weld according to the pressure, the initial pressure, and the cross-sectional area of the first sub-channel, non-destructive detection of the penetration depth of the weld can be achieved, realizing full inspection and improving the detection efficiency at the same time.

[0038] In some embodiments, the gas parameter includes the flow rate of the gas. The step of detecting the gas parameter in the gas flow channel and obtaining the penetration depth of the weld seam according to the gas parameter includes:

[0039] Detect the flow rate of the gas at the second opening, and obtain the penetration depth of the weld seam according to the flow rate of the gas, the initial flow rate, and the cross-sectional area of the first sub-channel;

[0040] Wherein, the initial flow rate is the flow rate measured at the second opening when the output electrode and the conductive connecting member are not welded.

[0041] By detecting the flow rate of the gas at the second opening and obtaining the penetration depth of the weld seam according to the flow rate of the gas, the initial flow rate, and the cross-sectional area of the first sub-channel, non-destructive detection of the penetration depth of the weld seam can be achieved, and full inspection can be realized while improving the detection efficiency.

[0042] In some embodiments, the number of the through holes and the gas flow channels is multiple and equal. The multiple gas flow channels are arranged separately from each other, and the multiple through holes are in one-to-one correspondence and communication with the first openings of the multiple gas flow channels; the step of introducing gas into the through holes so that the gas enters the gas flow channels from the first openings includes:

[0043] Introduce gas into each of the through holes respectively so that the gas enters each of the gas flow channels from the corresponding first opening;

[0044] The step of detecting the gas parameter in the gas flow channel and obtaining the penetration depth of the weld seam according to the gas parameter includes:

[0045] Detect the gas parameters in the multiple gas flow channels respectively, and obtain the penetration depth of the weld seam according to the multiple gas parameters.

[0046] By introducing gas into multiple gas flow channels provided on one output electrode for measurement, the data result of the penetration depth of the weld seam is more accurate, and the detection range of the penetration depth of the weld seam can be improved.

[0047] The above description is only an overview of the technical solution of the present application. In order to be able to understand the technical means of the present application more clearly, it can be implemented according to 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 understandable, the specific embodiments of the present application are specifically given below. Description of the Drawings

[0048] To more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the accompanying drawings required for the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on the structures shown in these drawings.

[0049] Figure 1 Schematic structural diagram of a vehicle according to some embodiments of the present application;

[0050] Figure 2 Exploded structural diagram of a battery device according to some embodiments of the present application;

[0051] Figure 3 Schematic structural diagram of the connection of multiple battery cells and conductive connectors according to some embodiments of the present application;

[0052] Figure 4 Schematic structural diagram of a battery cell according to some embodiments of the present application;

[0053] Figure 5 For Figure 4 Schematic structural diagram of the output pole of a conductive connector with a weld formed by welding in

[0054] Figure 6 Schematic structural diagram of the output pole of a battery cell according to some embodiments of the present application;

[0055] Figure 7 Schematic diagram of a first sub-channel with a rectangular cross-section and the weld part extending into the first sub-channel according to some embodiments of the present application;

[0056] Figure 8 Schematic structural diagram of an output pole, a weld, and a conductive connector according to some embodiments of the present application;

[0057] Figure 9 Schematic diagram of a first sub-channel with an oval cross-section according to some embodiments of the present application;

[0058] Figure 10 Schematic flow diagram of a welding quality detection method according to some embodiments of the present application;

[0059] Figure 11 Schematic structural diagram of a battery cell, a conductive connector, and an air joint applying the welding quality detection method according to some embodiments of the present application;

[0060] Figure 12 Schematic flow diagram of a welding quality detection method according to some embodiments of the present application;

[0061] Figure 13 Adopting Figure 12Schematic diagram of the output electrode, conductive connection member, and pressure gauge corresponding to the welding quality detection method;

[0062] Figure 14 Flow chart of the welding quality detection method according to some embodiments of the present application;

[0063] Figure 15 Adopt Figure 14 Schematic diagram of the output electrode, conductive connection member, and flow rate measuring instrument corresponding to the welding quality detection method;

[0064] Figure 16 Flow chart of the welding quality detection method according to some embodiments of the present application.

[0065] Explanation of the reference numerals in the drawings:

[0066] 1000, vehicle;

[0067] 100, battery device; 200, controller; 300, motor;

[0068] 10, box body; 11, upper cover; 12, bottom;

[0069] 20, battery cell; 30, conductive connection member; 301, through hole; 40, weld;

[0070] 1, body; 2, output electrode; 21, top surface; 22, side wall; 23, bottom surface; 3, air flow channel; 31, first sub-channel; 32, second sub-channel; 33, first opening; 34, second opening;

[0071] 5, air joint; 6, pressure gauge; 7, flow rate measuring instrument.

[0072] The realization, functional features, and advantages of the purpose of the present application will be further described in conjunction with the embodiments with reference to the accompanying drawings. Specific embodiments

[0073] Next, the technical solutions in the present embodiment will be clearly and completely described in conjunction with the accompanying drawings in the present embodiment. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present application without creative efforts shall fall within the protection scope of the present application.

[0074] It should be noted that all directional indications (such as up, down, left, right, front, back...) in this embodiment are only used to explain the relative position relationship and movement conditions between components in a specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indications will also change accordingly.

[0075] In addition, in this application, descriptions such as "first" and "second" are for descriptive purposes only, and should not be construed as indicating or implying their relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include at least one of such features. In the description of this application, "a plurality of" means at least two, such as two, three, etc., unless otherwise specifically defined.

[0076] In this application, unless otherwise clearly specified and limited, terms such as "connected" and "fixed" should be understood in a broad sense. For example, "fixed" can be a fixed connection, a detachable connection, or integrated; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and can be the communication inside two components or the interaction relationship between two components, unless otherwise clearly limited. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0077] In addition, the technical solutions between various embodiments of this application can be combined with each other, but it must be based on what can be achieved by those of ordinary skill in the art. When the combination of technical solutions is contradictory or cannot be achieved, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection required by this application. It should be understood that the specific embodiments described herein are only used to explain this application and are not used to limit this application.

[0078] In this application, the descriptions of orientations such as "up", "down", "front", "back", "left", and "right" are based on the orientations shown in the drawings, and are only used to explain the relative positional relationships between components in the posture shown in the drawings. If this specific posture changes, the directional indication will also change accordingly.

[0079] Currently, from the perspective of the development of the market situation, the application of power batteries is becoming more and more extensive. Power batteries are not only used in energy storage power systems such as hydraulic, thermal, wind, and solar power stations, but also widely used in electric transportation means such as electric bicycles, electric motorcycles, and electric vehicles, as well as in multiple fields such as aerospace. With the continuous expansion of the application fields of power batteries, the market demand is also constantly increasing.

[0080] During the manufacturing process of power batteries, it is necessary to use a laser to weld the conductive connecting piece and the output pole together. The conductive connecting piece generally refers to a bus bar, and the welding forms a welded joint, that is, a weld. If the welded joint fails, it may cause insufficient local strength of the battery device, and there may also be abnormal sampling signals, and even a risk of overheating and catching fire. Therefore, it is necessary to control the welding quality between the conductive connecting piece and the output pole.

[0081] However, in the industry, the detection method for welding quality is sampling inspection, and the detection efficiency is low. After careful research, the applicant found that for the quality detection of laser welding joints, penetration depth detection is an extremely important indicator, and the related technology is carried out by using metallographic testing on the welding joints. Metallographic testing requires obtaining a detection cross-section, and it is necessary to cut the tab and the output terminal from the weld, which is a destructive detection method. Therefore, it is impossible to conduct a full inspection, and only a part of the samples can be sampled to estimate the overall qualification rate. Moreover, this method is time-consuming and laborious, difficult to automate, and has low detection efficiency.

[0082] Therefore, the present application provides a battery cell, including a body and an output terminal. The output terminal includes a top surface, a bottom surface opposite to the top surface, and a sidewall connecting the top surface and the bottom surface. The bottom surface is connected to the body. An air flow channel is provided inside the output terminal, and a first opening and a second opening are provided at both ends of the air flow channel. The first opening is provided on the top surface, and the second opening is provided on the sidewall. The top surface is used for welding with a conductive connection member, and the formed weld extends into the air flow channel. The air flow channel is used for introducing gas to obtain the penetration depth of the weld by detecting gas parameters. By using the battery cell of the present application, a full inspection of the welded part of the output terminal and the tab can be realized, the control over the welding quality can be improved, and there is no need to cut the weld and grind for metallographic inspection. With the assistance of an automatic detection device, automatic detection can also be realized, and the detection efficiency is high.

[0083] Please refer to Figure 1 , Figure 1 FIG. 1000 is a schematic structural diagram of a vehicle 1000 provided in some embodiments of the present application. The electrical device can be the vehicle 1000, and the vehicle 1000 can be a fuel vehicle, a gas vehicle, or a new energy vehicle. The new energy vehicle can 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 can be provided at the bottom, head, or tail of the vehicle 1000. The battery device 100 can be used for power supply of the vehicle 1000. For example, the battery device 100 can be used as the operating power source of the vehicle 1000. The vehicle 1000 may further include a controller 200 and a motor 300. The controller 200 is used to control the battery device 100 to supply power to the motor 300. For example, it is used for the working power requirements during the start, navigation, and driving of the vehicle 1000.

[0084] In some embodiments of the present application, the battery device 100 can not only be used as the operating power source of the vehicle 1000, but also be used as the driving power source of the vehicle 1000, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1000.

[0085] Please refer to Figure 2 , Figure 2Exploded structural schematic diagram of the battery device 100 provided by some embodiments of the present application. The battery device 100 includes a box body 10 and battery cells 20, and the battery cells 20 are accommodated in the box body 10. Among them, the box body 10 is used to provide an accommodation space for the battery cells 20, and the box body 10 can adopt various structures. In some embodiments, the box body 10 may include an upper cover 11 and a bottom 12, the upper cover 11 and the bottom 12 cover each other, and the upper cover 11 and the bottom 12 jointly define an accommodation space for accommodating the battery cells 20. The bottom 12 may be a hollow structure with one end open, the upper cover 11 may be a plate-like structure, and the upper cover 11 covers the open side of the bottom 12 so that the upper cover 11 and the bottom 12 jointly define an accommodation space; the upper cover 11 and the bottom 12 may also both be hollow structures with one side open, and the open side of the upper cover 11 covers the open side of the bottom 12. Of course, the box body 10 formed by the upper cover 11 and the bottom 12 can be various shapes, such as a cylinder, a cuboid, etc.

[0086] The battery device 100 mentioned in the embodiments of the present application may include one or more battery cell assemblies for providing voltage and capacity. The battery cell assembly may include a plurality of battery cells 20, and the plurality of battery cells 20 are connected in series, parallel or in a hybrid connection through a busbar component.

[0087] In some embodiments, the battery cell assembly is usually formed by arranging a plurality of battery cells 20.

[0088] As an example, the battery cell assembly may be a battery module, and the battery module is formed by arranging and fixing a plurality of battery cells 20 into an independent module. As an example, the battery module may be formed by bundling a plurality of battery cells 20 with cable ties.

[0089] In some embodiments, the battery device 100 may be a battery pack, the battery pack includes a box body 10 and one or more battery cell assemblies, and the battery cell assemblies are accommodated in the box body 10.

[0090] 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.

[0091] As an example, the battery cell assembly may also be accommodated in the box body 10 by directly fixing a plurality of battery cells 20 to the box body 10.

[0092] In the battery device 100, there may be multiple battery cells 20. The multiple battery cells 20 can be connected in series, parallel, or in a combined series-parallel connection. A combined series-parallel connection means that there are both series and parallel connections among the multiple battery cells 20. The multiple battery cells 20 can be directly connected in series, parallel, or in a combined series-parallel connection together, and then the whole formed by the multiple battery cells 20 is accommodated in the box body 10. Of course, in the battery device 100, multiple battery cells 20 can also be first connected in series, parallel, or in a combined series-parallel connection to form a battery module, and then multiple battery modules are connected in series, parallel, or in a combined series-parallel connection to form a whole and are accommodated in the box body 10. The battery device 100 can also include other structures. For example, the battery device 100 can also include a busbar component for realizing the electrical connection among the multiple battery cells 20.

[0093] Among them, each battery cell 20 can be a secondary battery or a primary battery; it can also be a lithium-sulfur battery, a sodium-ion battery, or a magnesium-ion battery, 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.

[0094] Referring to Figures 3 - 6 , according to some embodiments of the present application, the present application provides a battery cell 20, including a body 1 and an output electrode 2. The output electrode 2 includes a top surface 21, a bottom surface 23 disposed opposite to the top surface 21, and a sidewall 22 connecting the top surface 21 and the bottom surface 23. The bottom surface 23 is connected to the body 1. An air flow channel 3 is provided inside the output electrode 2. Both ends of the air flow channel 3 are provided with a first opening 33 and a second opening 34. The first opening 33 is disposed on the top surface 21, and the second opening 34 is disposed on the sidewall 22. The top surface 21 is used for welding with a conductive connector 30, and the formed weld 40 extends into the air flow channel 3. The air flow channel 3 is used for introducing gas to obtain the penetration depth of the weld 40 by detecting the gas parameters.

[0095] It should be noted that the battery cell 20 includes a housing, an installation cavity is formed in the housing for accommodating a bare battery cell, an opening communicating with the installation cavity is formed in the housing, and a cover plate is disposed at the opening to seal the installation cavity. The body 1 here refers to the structure composed of the housing, the cover plate, the bare battery cell, etc. The output pole 2 of the battery cell 20 is provided with a certain distance extending out of the cover plate. The output pole 2 is also called a pole post. Generally, a battery cell 20 has two output poles 2, namely a positive output pole and a negative output pole, that is, the positive electrode and the negative electrode that we often mention. The output pole 2 is used to connect with the conductive connecting member 30. The conductive connecting member 30 can be a bus bar. The battery device further includes a sampling member. The sampling member can be a circuit board. The electrical signal of the output pole 2 is transmitted to the sampling member through the conductive connecting member 30, and finally transmitted to the battery management module to monitor the parameters of the battery cell 20. The parameters include but are not limited to the temperature, current, voltage and other information of the battery cell 20. The bottom surface 23 of the output pole 2 is connected to the body 1, specifically to the cover plate. At present, for the connection between the output pole 2 and the conductive connecting member 30, the generally adopted form is welding. The top surface 21 of the output pole 2 is welded to the conductive connecting member 30. The top surface 21 refers to the side of the output pole 2 away from the body 1, that is, the welding surface. The actual welding is carried out from the side of the conductive connecting member 30 away from the output pole 2. A weld seam 40 will be formed when the output pole 2 and the conductive connecting member 30 are laser welded. The welding quality is generally reflected by the detection of the weld seam 40. The index of the welding quality here at least includes the penetration depth of the weld seam 40. When the output pole 2 is cylindrical, the top surface 21 and the bottom surface 23 refer to the upper bottom surface circle and the lower bottom surface circle of the cylinder, and the side wall 22 refers to the side wall surface of the cylinder.

[0096] In the above embodiments of the present application, the air flow channel 3 is disposed inside the output pole 2. Two openings are formed at both ends of the air flow channel 3, namely a first opening 33 and a second opening 34. The first opening 33 penetrates through the top surface 21, and the second opening 34 penetrates through the side wall 22. After the battery cell 20 and the conductive connecting member 30 are welded, a weld seam 40 will be formed. The detection of the welding quality is mainly the detection of the penetration depth of the weld seam 40. The penetration depth here can be defined as: the length from the side of the conductive connecting member 30 away from the top surface 21 along the central axis direction of the output pole 2 to the top end of the weld seam 40. The top end of the weld seam 40 refers to the lowest end where the weld seam 40 extends into the air flow channel 3. It should be noted that the central axis direction of the output pole 2 in the present application can be the vertical direction, as shown by the arrow Z in Figure 6 and the horizontal direction in the present application is as shown by the arrow X in Figure 6 and the penetration depth in the present application is represented by H in Figure 5

[0097] ​When a part of the weld 40 extends into the gas flow channel 3, it will affect the gas flow in the gas flow channel 3. The penetration depth of the weld 40 can be detected by detecting the gas flow parameters after welding. The gas flow parameters here can be the pressure or the flow rate of the gas. Taking the gas flow rate as an example of the gas flow parameter, the initial gas flow rate V0 and the cross-sectional area S0 of the gas flow channel 3 can be obtained at the second opening 34 before welding. After welding, if the weld 40 extends into the gas flow channel 3, it will fill at least part of the space in the gas flow channel 3, resulting in a smaller cross-sectional area of the gas flow channel 3, which will affect the gas flow rate. If the gas flow rate obtained at the second opening 34 after welding is V1, and assuming that the cross-sectional area of the gas flow channel 3 after welding is S1, according to the principle that the gas flow through a certain cross-section per unit time is equal, we can get the following equation: S0 * V0 = S1 * V1. Thus, the cross-sectional area S1 of the gas flow channel 3 after welding can be obtained based on the measured S0, V0, and V1, and the penetration depth of the weld 40 can be obtained according to the shape of the cross-section. Refer to Figure 7 , when the cross-sectional shape is rectangular, S1 represents the cross-sectional area of the gas flow channel 3 after welding, and the hatched S2 represents the cross-sectional area of the weld 40 in the gas flow channel 3. Then, the cross-sectional area S0 of the first sub-channel 31 before welding = S1 + S2. The width k of the rectangle can be measured in advance. Then, the depth of the weld 40 in the gas flow channel 3 = (S0 - S1) / k, that is, the depth = S2 / k. Adding the distance h from the channel to the top surface 21 and the thickness of the conductive connector 30, the three data can be added to obtain the penetration depth of the weld 40. Specifically, the distance from the channel to the top surface 21 refers to the distance from the top end of the first sub-channel 31 to the top surface 21, as shown by h in Figure 5 or Figure 6 . When the cross-section is circular or elliptical, the depth of the weld 40 in the first sub-channel 31 can also be obtained by combining geometric knowledge, and then the penetration depth of the weld 40 can be obtained. When the gas flow parameter is pressure, the penetration depth of the weld 40 is also obtained by a similar method, which will be discussed in detail in the subsequent method steps. For the specific method of introducing gas into the first opening 33, a through hole 301 can be provided at the position of the conductive connector 30 corresponding to the first opening 33, and gas is introduced into the gas flow channel 3 from the first opening 33 by introducing gas into the through hole 301. And if the gas flow channel 3 is not completely closed by the weld 40, the gas will flow out from the second opening 34.

[0098] By arranging an air flow channel 3 inside the output electrode 2, after welding with the conductive connecting member 30 is completed, gas is introduced through the first opening 33 on the top surface 21. The penetration depth of the weld 40 can be obtained based on the detected gas pressure or gas flow rate. In this embodiment, non-destructive detection is performed by introducing gas into the air flow channel 3, which is a non-destructive detection method. Thus, full inspection of the welded part between the output electrode 2 and the conductive connecting member 30 can be achieved, improving the control over the welding quality. Moreover, there is no need to cut the weld 40 and grind for metallographic inspection. With the assistance of an automatic detection device, automatic detection can also be realized, and the detection efficiency is high.

[0099] Referring to Figure 6 and Figure 8 , in some embodiments, the air flow channel 3 includes a first sub-channel 31 and a second sub-channel 32 that are interconnected. One end of the second sub-channel 32 remote from the first sub-channel 31 is provided with a first opening 33, and one end of the first sub-channel 31 remote from the second sub-channel 32 is provided with a second opening 34. The first sub-channel 31 is a horizontal sub-channel with a constant cross-section, and the central axis of the first sub-channel 31 is perpendicularly arranged with respect to the central axis of the output electrode 2.

[0100] The air flow channel 3 is composed of two interconnected sub-channels. One end of the first sub-channel 31 is connected to one end of the second sub-channel 32. The other end of the first sub-channel 31 is the second opening 34, and the other end of the second sub-channel 32 is the first opening 33. For the convenience of measurement, the first sub-channel 31 is arranged as a horizontal sub-channel with a constant cross-section, that is, arranged in a horizontal manner and with the same cross-section at each location. For example, it can be a horizontally placed cylindrical channel, an elliptical channel, a rectangular channel, or a square channel. Here, the horizontal direction is the direction perpendicular to the vertical direction. As shown by the arrow X in Figure 6 , it can also be said that the central axis of the first sub-channel 31 is horizontally arranged, the central axis of the output electrode 2 is vertically arranged, and the central axes of the two are perpendicular to each other. During actual welding, the welding position will avoid the first opening 33 so that the weld 40 will not extend into the second sub-channel 32. During actual detection, the weld 40 extends into the first sub-channel 31. Arranging the first sub-channel 31 with the same cross-section and horizontally is mainly for the convenience of measuring the penetration depth of the weld 40. Because if the first sub-channel 31 is inclined or the cross-sections at different positions are different, calculating the penetration depth of the weld 40 will be more complicated.

[0101] By arranging the first sub-channel 31 of the channel horizontally and with a constant cross-section, and the weld 40 extending into the first sub-channel 31, it is convenient to calculate the penetration depth of the weld 40 based on the measured gas parameters.

[0102] In some embodiments, a plane perpendicular to the central axis of the first sub-channel 31 is defined as the cross-section of the first sub-channel 31. The projected dimension of the cross-section of the first sub-channel 31 on the plane where the top surface 21 is located is defined as the width of the first sub-channel 31. The dimension of the first sub-channel 31 along the central axis direction of the output pole 2 is defined as the height of the first sub-channel 31. Then: the height of the first sub-channel 31 is greater than or equal to the width of the first sub-channel 31.

[0103] When the first sub-channel 31 is horizontally arranged, the central axis of the first sub-channel 31 is also horizontally arranged. The cross-section of the first sub-channel 31 is a vertical section, and the top surface 21 is horizontally arranged. In this way, the projection of the cross-section of the first sub-channel 31 on the plane where the top surface 21 is located is a straight line, and the length of the projected dimension straight line is defined as the width of the first sub-channel 31. The dimension of the first sub-channel 31 along the central axis direction of the output pole 2, that is, the height of the cross-section of the first sub-channel 31 along the vertical direction. When the cross-section of the first sub-channel 31 is circular, rectangular or square, it is the length along the central axis direction of the output pole 2. However, when the cross-section of the first sub-channel 31 is elliptical or other irregular shapes, the dimension along the central axis direction of the output pole 2 here refers to the maximum length of the cross-section of the first sub-channel 31 in the vertical direction. If it is an ellipse, it is the major axis of the ellipse. Designing the width of the first sub-channel 31 to be smaller, because if the width is set too large, it will cause a reduction in the internal strength of the output pole 2 and there is a risk of collapse of the output pole 2. And designing the width to be smaller can also make the cross-section of the position where the weld 40 passes be completely filled by the weld 40, reducing the possibility that there are gaps where the air can flow through where the weld 40 reaches, and can improve the measurement accuracy. It should be noted here that in actual application scenarios, by limiting the width, it can be basically ensured that the weld 40 will fill the channel position it passes through. And setting the height larger can increase the measurement range of the weld penetration depth.

[0104] By setting the height of the first sub-channel 31 to be greater than or equal to the width of the first sub-channel 31, designing the height of the first sub-channel 31 to be larger is beneficial to increasing the measurement range of the weld penetration depth, and designing the width to be smaller is beneficial to reducing the risk of collapse of the output pole 2 and is beneficial to improving the measurement accuracy.

[0105] Refer to Figure 9 In some embodiments, the cross-section of the first sub-channel 31 is an ellipse, the major axis of the ellipse is arranged parallel to the central axis of the output pole 2, the height of the first sub-channel 31 is equal to the major axis dimension of the ellipse, and the width of the first sub-channel 31 is equal to the minor axis dimension of the ellipse.

[0106] Figure 9The major axis of the ellipse is represented by a, and the minor axis of the ellipse is represented by b. Taking the cross-section of the first sub-channel 31 being an ellipse as an example, those skilled in the art can understand that an ellipse has a major axis and a minor axis, and the size of the major axis is greater than that of the minor axis. Because when designing the placement direction of the first sub-channel 31, the major axis of the ellipse is set parallel to the central axis of the output pole 2, that is, the vertical direction. In this way, the height of the first cross-section is the size of the major axis of the ellipse, and the width of the first cross-section is the length of the minor axis of the ellipse. In this way, when the cross-sectional shape is an ellipse, the height of the first sub-channel 31 can be increased as much as possible and the width of the first sub-channel 31 can be reduced as much as possible.

[0107] By setting the height of the first sub-channel 31 equal to the size of the major axis of the ellipse and the width of the first sub-channel 31 equal to the size of the minor axis of the ellipse, the height of the first sub-channel 31 can be increased as much as possible, which is beneficial to expanding the measurement range of the melt depth; the width of the first sub-channel 31 can be reduced as much as possible, which is beneficial to reducing the risk of the output pole 2 collapsing and is also beneficial to improving the measurement accuracy.

[0108] In some embodiments, the cross-section of the first sub-channel 31 is circular, the height of the first sub-channel 31 is equal to the width of the first sub-channel 31, and both are the same as the diameter of the circle.

[0109] Taking the cross-section of the first sub-channel 31 being circular as an example, at this time the first sub-channel 31 is actually a cylindrical channel. Those skilled in the art can understand that the diameters of a circle are the same. Therefore, no matter how it is placed in terms of orientation, the width and height of the first sub-channel 31 are equal and are both equal to the diameter length of the circle. Of course, in some other embodiments, the cross-sectional shape of the first sub-channel 31 can also be rectangular or square.

[0110] By setting the first sub-channel 31 as a cylindrical channel, not only is the production more convenient, but also it can have appropriate width and height, and can also meet the detection requirements.

[0111] In some embodiments, the width of the first sub-channel is defined as d; where, 0 < d ≤ 0.3 mm.

[0112] As described above, the width of the first sub-channel 31 here refers to the projection dimension of the cross-section of the first sub-channel 31 on the plane where the top surface 21 is located. The projection pattern is a straight line, and the projection dimension is the length of the straight line. The width here satisfies 0 < d ≤ 0.3 mm, and it can be 0.01 mm, 0.05 mm, 0.1 mm, 0.15 mm, 0.2 mm, 0.25 mm or 0.3 mm, or any value within the above range. The principle for setting the upper limit of the width is that the smaller the width, the smaller the impact on the structural strength of the output pole 2, and when the weld 40 extends into the first sub-channel 31, it can better fill the passing position, which is beneficial to improving the accuracy of penetration depth detection. Through experimental detection, it is known that it is more appropriate to design the width to be less than 0.3 mm.

[0113] By setting the appropriate width of the first sub-channel 31, the weld 40 can be made to fill the passing position as much as possible, that is, there will be no air flow passing above the position reached by the weld 40, improving the accuracy of penetration depth detection.

[0114] Refer to Figure 10 , in some embodiments, the cross-sectional area of the first sub-channel 31 is the same as the cross-sectional area of the second sub-channel 32; or, the shapes and sizes of the first sub-channel 31 and the second sub-channel 32 are the same.

[0115] In fact, since the weld 40 extends into the first sub-channel 31, by limiting the cross-sectional shape and placement position of the first sub-channel 31, the detection of the penetration depth can be achieved, and there are not many limitations on the shape and size of the second sub-channel 32. However, for the sake of improving the convenience of detection, we can set the cross-sectional area of the first sub-channel 31 to be the same as the cross-sectional area of the second sub-channel 32. The cross-section of the second sub-channel 32 is the section made perpendicular to the central axis of the second sub-channel 32. When the second sub-channel 32 is vertically arranged, the cross-section of the second sub-channel 32 is the horizontal section. Setting the cross-sectional areas of the two to be the same, or the shapes and sizes of the first sub-channel 31 and the second sub-channel 32 to be the same, can simplify the calculation steps for obtaining the penetration depth after obtaining the air flow parameters. And because the cross-sectional areas are the same, during measurement, only the cross-sectional area of one sub-channel needs to be measured, and the measurement is also more convenient.

[0116] By setting the cross-sectional area of the first sub-channel 31 to be the same as the cross-sectional area of the second sub-channel 32; or, the shapes and sizes of the first sub-channel 31 and the second sub-channel 32 to be the same, the measurement and calculation steps for obtaining the penetration depth are both more convenient.

[0117] In some embodiments, there are multiple air flow channels 3, the multiple air flow channels 3 are isolated from each other, the first openings 33 of the multiple air flow channels 3 are spaced apart on the top surface 21, and the second openings 34 of the multiple air flow channels 3 are spaced apart on the side wall 22.

[0118] The weld seam 40 generally surrounds the output electrode 2 in a circle, that is, it is circular or annular. There may be slight differences in the weld seams 40 at different positions on the circle. Measuring the penetration depth of the weld seam 40 at a single position may not be accurate enough. Therefore, by providing multiple air flow channels 3 that are isolated from each other and do not communicate with each other, and each having its own first opening 33 and second opening 34, the multiple first openings 33 are spaced apart, and the multiple second openings 34 are also spaced apart. Gas is introduced into each first opening 33 respectively, and the gas parameters of each air flow channel 3 are detected respectively. Thus, multiple penetration depth values can be obtained. The average value can be taken based on the multiple penetration depth values obtained, or the median can be taken. It is also possible to obtain the penetration depth range of the weld seam 40 through the multiple penetration depth values. In this way, the measurement of the weld seam 40 is more accurate and comprehensive.

[0119] By providing multiple air flow channels 3 and the weld seam 40 extends into at least part of the air flow channels 3, multiple penetration depth values can be obtained and the measurement result is more accurate.

[0120] In some embodiments, the distance from the top of the first sub-channel 31 to the top surface 21 is defined as the depth of the first sub-channel 31, and the depths of the multiple first sub-channels 31 are not completely the same.

[0121] As shown by h in Figure 5 or Figure 6 Those skilled in the art can understand that assuming that the first sub-channel 31 of the air flow channel 3 is set deeper and the penetration depth of the weld seam 40 is smaller, then there may be a situation where the weld seam 40 does not extend into the air flow channel 3. In this case, it may be difficult to detect the penetration depth of the smaller weld seam 40. However, if the penetration depth of the weld seam 40 is larger and has completely filled the bottom end of the first sub-channel 31, then our detection result can only quantitatively show that the penetration depth has reached the bottom end of the first sub-channel 31, but it is difficult to quantitatively show the specific value of the penetration depth. Therefore, the heights of the respective air flow channels 3 can be set to be not completely the same to be able to adapt to the measurement of weld seams 40 with different penetration depths.

[0122] By providing the depths of the multiple first sub-channels 31 to be not completely the same, it can be applicable to the measurement of weld seams 40 with different penetration depths and improve the measurement range of the penetration depth of the weld seam 40.

[0123] In some embodiments, the depths of the multiple first sub-channels 31 are set in a gradient.

[0124] The gradient setting can be a setting with gradually increasing depth or gradually decreasing depth. Setting multiple gradient ranges can measure weld seams 40 with different penetration depths.

[0125] By setting the depths of multiple first sub-channels 31 in a gradient manner, it can be applicable to the measurement of weld seams 40 with different penetration depths, and the measurement range of the penetration depth of the weld seam 40 is improved.

[0126] In some embodiments, the top surface 21 is a circular surface, and the shape of the weld seam 40 is an annular shape; or,

[0127] The top surface 21 is a rectangular surface, and the shape of the weld seam 40 is a rectangle.

[0128] It should be noted here that the shape of the top surface 21 in this application is not specifically limited. It can be a circular surface, a rectangular surface or other shapes, which can be regular shapes or irregular shapes. Correspondingly, the shape of the weld seam 40 is not specifically limited either, as long as the weld seam 40 can extend into the air flow channel 3. In a specific embodiment, when the top surface 21 is a circular surface or a rectangular surface, the weld seam 40 is correspondingly an annular shape or a rectangle. Since the air flow channel 3 extends from the top surface 21 to the side wall 22, designing a closed shape of the weld seam 40 can enable the weld seam 40 to intersect with the air flow channel 3, or rather, extend into the air flow channel 3.

[0129] By setting the top surface 21 and the weld seam 40 to be adapted shapes, it is convenient for the weld seam 40 to extend into the air flow channel 3.

[0130] In some embodiments, the first opening 33 is an air inlet, and the second opening 34 is an air outlet; or,

[0131] The first opening 33 is an air outlet, and the second opening 34 is an air inlet.

[0132] Gas can be introduced through the first opening 33, flow through the air flow channel 3 and then be discharged from the second opening 34. At this time, the first opening 33 is an air inlet, and the second opening 34 is an air outlet. Gas can be introduced through the second opening 34 and then discharged from the first opening 33. At this time, the second opening 34 is an air inlet, and the first opening 33 is an air outlet. Those skilled in the art can set it according to actual needs.

[0133] By setting the first opening 33 as an air inlet or an air outlet, and correspondingly setting the second opening 34 as an air outlet or an air inlet, it can correspond to the actual application scenario.

[0134] According to some embodiments of the present application, the present application provides a battery cell 20, including a body 1 and an output terminal 2. The output terminal 2 includes a top surface 21, a bottom surface 23 disposed opposite to the top surface 21, and a sidewall 22 connecting the top surface 21 and the bottom surface 23. The bottom surface 23 is connected to the body 1. An air flow channel 3 is provided inside the output terminal 2. The air flow channel 3 includes a first sub-channel 31 and a second sub-channel 32 that communicate with each other. One end of the second sub-channel 32 away from the first sub-channel 31 is provided with a first opening 33, and one end of the first sub-channel 31 away from the second sub-channel 32 is provided with a second opening 34. The first sub-channel 31 is a horizontal sub-channel with a constant cross-section. The central axis of the first sub-channel 31 is perpendicular to the central axis of the output terminal 2. The first opening 33 is provided on the top surface 21, and the second opening 34 is provided on the sidewall 22. The cross-sectional shape of the first sub-channel 31 can be circular or elliptical. A plane perpendicular to the central axis of the first sub-channel 31 is defined as the cross-section of the first sub-channel 31. The projection size of the cross-section of the first sub-channel 31 on the plane where the top surface 21 is located is defined as the width of the first sub-channel 31, and the size of the first sub-channel 31 along the central axis direction of the output terminal 2 is defined as the height of the first sub-channel 31. Then: the height of the first sub-channel 31 is greater than or equal to the width of the first sub-channel 31. Wherein, the width of the first sub-channel 31 is d. Wherein, 0 < d ≤ 0.3 mm. The shapes and sizes of the first sub-channel 31 and the second sub-channel 32 can be set to be the same. The first opening 33 is an air inlet, and the second opening 34 is an air outlet. The top surface 21 is used for welding with the conductive connector 30, and the formed weld 40 extends into the air flow channel 3. The air flow channel 3 is used for introducing gas to obtain the penetration depth of the weld 40 by detecting gas parameters. This embodiment performs non-destructive testing by introducing gas into the air flow channel 3, which is a non-destructive testing method. Thus, full inspection of the welded part of the output terminal 2 and the conductive connector 30 can be achieved, improving the control of welding quality. And it is not necessary to cut the weld 40 and polish for metallographic inspection. With the assistance of an automatic detection device, automatic detection can also be realized, and the detection efficiency is high.

[0135] Referring to Figure 10 , according to some embodiments of the present application, the present application provides a welding quality detection method for detecting a weld 40 formed by welding a conductive connector 30 to the output terminal 2 of the above-mentioned battery cell 20. The conductive connector 30 is provided with a through hole 301 communicating with the first opening 33. The weld 40 is spaced from the first opening 33. The welding quality detection method includes:

[0136] S100, introducing gas into the through hole 301 so that the gas enters the air flow channel 3 from the first opening 33.

[0137] Combined with reference to Figure 11, a through hole 301 is provided on the conductive connecting member 30. The through hole 301 is correspondingly arranged with the first opening 33. After the conductive connecting member 30 reaches the top surface 21 of the output electrode 2, the through hole 301 communicates with the first opening 33. Gas is introduced from the side of the conductive connecting member 30 facing away from the output electrode 2. Specifically, gas can be introduced through the air joint 5. The air joint 5 can be a compressed air joint. The air joint 5 abuts against the conductive connecting member 30. The air joint 5 can be made of rubber or other soft and wear-resistant materials, and can form a sealing interface with the conductive connecting member 30. In this way, the structure is relatively simple, and the sealing fit can improve the accuracy of the test. Of course, the air joint 5 can also be made of steel or other hard non-metallic materials, and it is necessary to cooperate with a sealing ring or gasket to form a sealing interface with the bar piece. In this way, the sealing ring structure is convenient for replacement, the part cost is low, and the non-metallic air joint 5 can effectively reduce the risk of short circuit and sparking during the debugging process. Of course, the number of air joints 5 can be one or more. Multiple air joints 5 can simultaneously introduce gas into multiple battery cells 20, and the detection of multiple battery cells 20 can be realized at one time, meeting the requirements of the production rhythm of automated production. Specifically, the air flow enters from the through hole 301, enters the air flow channel 3 through the first opening 33, and flows out from the second opening 34.

[0138] S200, detecting the gas parameters in the air flow channel 3, and obtaining the penetration depth of the weld 40 according to the gas parameters.

[0139] Since the weld 40 extends into the air flow channel 3 and fills part of the space of the air flow channel 3, the cross-sectional area of the air flow channel 3 becomes smaller, which will affect the flow of gas, such as affecting the pressure and flow rate of the gas. When there is no weld 40, that is, before welding, gas can be introduced to measure the gas parameters and the parameters of the air flow channel 3. After welding is completed, the corresponding gas parameters are measured. Thus, according to the knowledge of fluid mechanics, the penetration depth of the weld 40 can be obtained.

[0140] By setting the gas to be introduced into the through hole 301 so that the gas enters the air flow channel 3 from the first opening 33, detecting the gas parameters in the air flow channel 3, and obtaining the penetration depth of the weld 40 according to the gas parameters. In this embodiment, non-destructive testing is carried out by introducing gas into the air flow channel 3, which is a non-destructive testing method. Thus, full inspection of the welded part between the output electrode 2 and the bar piece can be realized, the control of the welding quality can be improved, and it is not necessary to cut the weld 40 and grind the metallographic inspection. With the assistance of an automatic detection device, automatic detection can also be realized, and the detection efficiency is high.

[0141] Refer to Figure 12 , in some embodiments, the gas parameters include the pressure of the gas. The steps of detecting the gas parameters in the air flow channel 3 and obtaining the penetration depth of the weld 40 according to the gas parameters include:

[0142] S201. Detect the pressure of the gas at the first opening 33, and obtain the penetration depth of the weld 40 based on the pressure, the initial pressure, and the cross-sectional area of the first sub-channel 31.

[0143] Among them, the initial pressure is the pressure measured at the first opening 33 when the output electrode 2 and the conductive connecting member 30 are not welded, and the cross-sectional area of the first sub-channel 31 is the cross-sectional area of the first sub-channel 31 when the output electrode 2 and the conductive connecting member 30 are not welded.

[0144] Combined with reference to Figure 13 , the pressure can be measured by the pressure gauge 6. The initial pressure P0 of the gas and the cross-sectional area S0 of the gas flow channel 3 can be obtained at the first opening 33 before welding. After welding is completed, if the weld 40 extends into the gas flow channel 3, it will fill at least part of the space in the gas flow channel 3, resulting in a decrease in the cross-sectional area of the gas flow channel 3, which will affect the gas pressure. If the gas pressure obtained at the second opening 34 after welding is P1, assuming that the cross-sectional area of the gas flow channel 3 after welding is S1, and the pressure of the introduced gas can be ensured to be constant through the air joint 5, we can obtain the following equation: S0 * P0 = S1 * P1. Thus, the cross-sectional area S1 of the gas flow channel 3 after welding can be obtained based on the measured S0, P0, and P1, and the depth of the weld 40 entering the gas flow channel 3 can be obtained according to the shape of the cross-section. When the cross-sectional shape is rectangular, the width k of the rectangle can be measured in advance, then the depth of the weld 40 in the gas flow channel 3 = (S0 - S1) / k, plus the distance h from the first sub-channel 31 to the top surface 21, and the thickness of the conductive connecting member 30. Adding these three data together can obtain the penetration depth of the weld 40. Those skilled in the art can understand that when the cross-section is circular or elliptical, the penetration depth of the weld 40 can also be obtained by combining geometric knowledge.

[0145] By detecting the pressure of the gas at the first opening 33 and obtaining the penetration depth of the weld 40 based on the pressure, the initial pressure, and the cross-sectional area of the first sub-channel 31, non-destructive detection of the penetration depth of the weld 40 can be achieved, realizing full inspection and improving the detection efficiency at the same time.

[0146] Refer to Figure 14 , in some embodiments, the gas parameters include the gas flow rate. The steps of detecting the gas parameters in the gas flow channel 3 and obtaining the penetration depth of the weld 40 based on the gas parameters include:

[0147] S202. Detect the gas flow rate at the second opening 34, and obtain the penetration depth of the weld 40 based on the gas flow rate, the initial flow rate, and the cross-sectional area of the first sub-channel 31.

[0148] Among them, the initial flow rate is the flow rate measured at the second opening 34 when the output electrode 2 and the conductive connecting member 30 are not welded.

[0149] Referring to Figure 15 , a flow velocity meter 7 can be provided at the second opening 34 to measure the flow velocity of the gas. Specifically, the initial flow velocity V0 of the gas and the cross-sectional area S0 of the gas flow channel 3 can be obtained at the second opening 34 before welding. After welding is completed, if the weld 40 extends into the gas flow channel 3, it will fill at least part of the space in the gas flow channel 3, resulting in a decrease in the cross-sectional area of the gas flow channel 3, which will affect the flow velocity of the gas. If the flow velocity of the gas obtained at the second opening 34 after welding is V1, and assuming that the cross-sectional area of the gas flow channel 3 after welding is S1, based on the principle that the gas flow rate through a certain cross-section per unit time is equal, we can obtain the following equation: S0*V0 = S1*V1. Thus, the cross-sectional area S1 of the gas flow channel 3 after welding can be obtained based on the measured S0, V0, and V1. As described in the previous embodiment, the penetration depth of the weld 40 can be obtained according to the shape of the cross-section. When the cross-sectional shape is rectangular and the width k of the rectangle can be measured in advance, the depth of the weld 40 in the gas flow channel 3 = (S0 - S1) / k. Adding the distance h from the channel to the top surface 21 and the thickness of the conductive connector 30, the three data can be added together to obtain the penetration depth of the weld 40. When the cross-section is circular or elliptical, the penetration depth of the weld 40 can be obtained by combining geometric knowledge.

[0150] By detecting the flow velocity of the gas at the second opening 34 and obtaining the penetration depth of the weld 40 based on the flow velocity of the gas, the initial flow velocity, and the area of the cross-section of the first sub-channel 31, non-destructive detection of the penetration depth of the weld 40 can be achieved, enabling full inspection and improving the detection efficiency at the same time.

[0151] Referring to Figure 16 , in some embodiments, the number of through holes 301 and gas flow channels 3 is multiple and equal. The multiple gas flow channels 3 are arranged separately from each other, and the multiple through holes 301 are in one-to-one correspondence and communication with the first openings 33 of the multiple gas flow channels 3; the steps of S100 include:

[0152] S110, introducing gas into each through hole 301 respectively, so that the gas enters each gas flow channel 3 from the corresponding first opening 33.

[0153] When the number of gas flow channels 3 is multiple, the corresponding air connectors 5 are also multiple. Each air connector 5 is arranged corresponding to a first opening 33, and the gas flow channels 3 are also arranged separately from each other. Therefore, the air flow in each gas flow channel 3 will not affect each other.

[0154] The steps of S200 include:

[0155] S210, detecting the gas parameters in the multiple gas flow channels 3 respectively, and obtaining the penetration depth of the weld 40 based on the multiple gas parameters.

[0156] For each gas flow channel 3, a method of detecting gas parameters is adopted to obtain the penetration depth of the weld 40. The setting of multiple gas flow channels 3 is considered from the following two aspects:

[0157] Firstly, the weld 40 generally surrounds the output electrode in a circle, which is circular or annular. There may be slight differences in the weld 40 at different positions on the circle. Measuring the penetration depth of the weld 40 at a single position may result in inaccurate measurement. Therefore, by setting multiple gas flow channels 3, the multiple gas flow channels 3 are isolated from each other and not connected. Each has its own first opening 33 and second opening 34. The multiple first openings 33 are distributed at intervals, and the multiple second openings 34 are also distributed at intervals. Gas is introduced into each first opening 33 respectively, and the gas parameters of each gas flow channel 3 are detected respectively. Thus, multiple penetration depth values can be obtained. The average value can be taken from the multiple penetration depth values obtained, or the median can be taken. The penetration depth range of the weld 40 can also be obtained through the multiple penetration depth values. In this way, the measurement is more comprehensive and accurate.

[0158] Secondly, those skilled in the art can understand that assuming the first sub-channel 31 of the gas flow channel 3 is relatively deep and the penetration depth of the weld 40 is small, then there may be a situation where the weld 40 does not extend into the gas flow channel 3. In this case, it may be difficult to detect the penetration depth of the smaller weld 40. Additionally, if the penetration depth of the weld 40 is large and has completely filled the bottom end of the first sub-channel 31, then the result of our detection can only quantitatively show that the penetration depth has reached the bottom end of the first sub-channel 31, but it is difficult to quantitatively explain the specific value of the penetration depth. Therefore, the heights of the respective gas flow channels 3 can be set to be not completely the same, or set in a gradient manner, so as to be able to adapt to the measurement of welds 40 with different penetration depths.

[0159] By introducing gas into multiple gas flow channels 3 provided on one output electrode 2 for measurement, the data result of the penetration depth of the weld 40 is more accurate, and the detection range of the penetration depth of the weld 40 can be improved.

[0160] According to some embodiments of the present application, the present application provides a welding quality detection method for detecting a weld 40 formed by welding an output pole 2 of a conductive connecting member 30 and the above-mentioned battery cell 20. The conductive connecting member 30 is provided with a through hole 301 communicating with a first opening 33, and the weld 40 is spaced from the first opening 33. The welding quality detection method includes: introducing a gas into the through hole 301 so that the gas enters the air flow channel 3 from the first opening 33; detecting the pressure of the gas at the first opening 33, and obtaining the penetration depth of the weld 40 according to the pressure, the initial pressure and the cross-sectional area of the first sub-channel 31; or detecting the flow rate of the gas at the second opening 34, and obtaining the penetration depth of the weld 40 according to the flow rate of the gas, the initial flow rate and the cross-sectional area of the first sub-channel 31. The embodiments of the present application can achieve non-destructive detection of the penetration depth of the weld 40, can achieve full inspection of the weld 40, and the automated detection can improve the detection efficiency.

[0161] According to some embodiments of the present application, the present application provides a battery device 100, including a box body 10, a battery cell 20, a conductive connecting member 30, a sampling member and a battery management module. The box body 10 is provided with a receiving cavity; the battery cell 20 is disposed in the receiving cavity, and the battery cell 20 is the above-mentioned battery cell 20; the conductive connecting member 30 is provided with a through hole 301 communicating with a first opening 33, the conductive connecting member 30 is welded to the top surface 21 of the output pole 2 of the battery cell 20, and the formed weld 40 extends into the air flow channel 3, and the weld 40 is spaced from the first opening 33; the sampling member is electrically connected to the conductive connecting member 30 and the battery management module.

[0162] As shown above, the conductive connector 30 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 is electrically connected to 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 the monitoring of the battery cell 20. The conductive connector 30 is provided with a through hole 301 connected to the first opening 33, and gas is introduced from the side of the conductive connector 30 away from the output pole 2. Specifically, the gas can be introduced through a compressed air structure. The air connector 5 is in contact with the conductive connector 30. The air connector 5 can be made of rubber or other soft and wear-resistant materials, which can form a sealing interface with the bar. Such a structure is relatively simple, and the sealing cooperation can improve the accuracy of the test. Of course, the air connector 5 can also be made of steel or other hard non-metallic materials, and a sealing ring or a sealing gasket is required to form a sealing interface with the conductive connector 30. In this way, the sealing ring structure is easy to replace, the parts cost is low, and the non-metallic air connector 5 can effectively reduce the risk of short circuit ignition during the debugging process. Of course, the number of air connectors 5 can be one or more, and multiple air connectors 5 can simultaneously pass gas to multiple battery cells 20, and detect multiple battery cells 20 at one time, meeting the rhythm requirements of automated production. In addition, the air flow channel 3 can connect the center hole of the output pole 2 and the center hole of the conductive connector 30, or the air flow channel 3 can be set at other positions of the output pole 2 and the conductive connector 30, so as to facilitate compatibility with a variety of weld 40 positions and weld 40 shapes.

[0163] The output pole 2 and the sampling piece are electrically connected via the conductive connector 30, and the electrical signal is transmitted to the battery management module via the sampling piece to monitor the signal of the battery cell 20. At the same time, the battery cell 20 used can be passed with gas for non-destructive testing, so as to efficiently detect the penetration depth and width of the weld 40.

[0164] According to some embodiments of the present application, the present application provides an electric device, which includes an equipment body and the above-mentioned battery device 100, and the battery device 100 is arranged in the equipment body. The electric device can be a vehicle 1000. Since the electric device includes any technical solution of all the above embodiments, it has at least all the beneficial effects brought by any of the above technical solutions, which will not be repeated here one by one.

[0165] The above description is only an optional embodiment of the present application, and does not limit the patent scope of the present application. All equivalent structural changes 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 are included in the patent protection scope of the present application.

Claims

1. A battery cell, characterized in that, It includes a body and an output electrode. The output electrode includes a top surface, a bottom surface opposite to the top surface, and a sidewall connecting the top surface and the bottom surface. The bottom surface is connected to the body. An air flow channel is provided inside the output electrode. The air flow channel includes a first sub-channel and a second sub-channel that communicate with each other. One end of the second sub-channel away from the first sub-channel is provided with a first opening, and one end of the first sub-channel away from the second sub-channel is provided with a second opening. The first opening is provided on the top surface, and the second opening is provided on the sidewall. The first sub-channel is a horizontal sub-channel with a constant cross-section, and the central axis of the first sub-channel is perpendicular to the central axis of the output electrode; Define the plane perpendicular to the central axis of the first sub-channel as the cross-section of the first sub-channel. Define the projection dimension of the cross-section of the first sub-channel on the plane where the top surface is located as the width of the first sub-channel. Define the dimension of the first sub-channel along the central axis direction of the output electrode as the height of the first sub-channel. Then: the height of the first sub-channel is greater than or equal to the width of the first sub-channel, so that the cross-section of the position where the weld passes through the first sub-channel is filled by the weld; The top surface is used for welding with a conductive connecting piece, and the formed weld extends into the first sub-channel. The air flow channel is used for introducing gas to obtain the penetration depth of the weld by detecting gas parameters.

2. The battery cell according to claim 1, wherein The cross-section of the first sub-channel is an ellipse, and the major axis of the ellipse is parallel to the central axis of the output electrode. The height of the first sub-channel is equal to the major axis dimension of the ellipse, and the width of the first sub-channel is equal to the minor axis dimension of the ellipse.

3. The battery cell according to claim 2, characterized in that, The cross-section of the first sub-channel is a circle, and the height of the first sub-channel is equal to the width of the first sub-channel, and both are the same as the diameter of the circle.

4. The battery cell according to any one of claims 1 to 3, characterized in that, Define the width of the first sub-channel as d; where, 0 < d ≤ 0.3 mm.

5. The battery cell according to claim 1, wherein the cross-sectional area of the first sub-channel is the same as the cross-sectional area of the second sub-channel; or, the first sub-channel and the second sub-channel have the same shape and size.

6. The battery cell according to any one of claims 1 to 3, characterized in that, The number of the air flow channels is multiple. The multiple air flow channels are isolated from each other. The first openings of the multiple air flow channels are spaced apart on the top surface, and the second openings of the multiple air flow channels are spaced apart on the sidewall.

7. The battery cell according to claim 6, wherein Define the distance from the top of the first sub-channel to the top surface as the depth of the first sub-channel. The depths of the multiple first sub-channels are not completely the same.

8. The battery cell according to claim 7, characterized in that, The depths of the multiple first sub-channels are arranged in a gradient.

9. The battery cell according to any one of claims 1 to 3, characterized in that, The top surface is a circular surface, and the shape of the weld is an annular shape; or, The top surface is a rectangular surface, and the shape of the weld is a rectangle.

10. The battery cell according to any one of claims 1 to 3, wherein the first opening is an air inlet, and the second opening is an air outlet; or, the first opening is an air outlet, and the second opening is an air inlet.

11. A welding quality detection method for detecting a weld formed by welding an output electrode of a conductive connecting member to a battery cell described in any one of claims 1 to 10. The conductive connecting member is provided with a through hole communicating with the first opening, and the weld is spaced from the first opening. It is characterized in that, The welding quality detection method includes: Introduce gas into the through hole so that the gas enters the air flow channel from the first opening; Detect the gas parameters in the air flow channel, and obtain the penetration depth of the weld seam according to the gas parameters and the initial gas parameters measured when not welded.

12. The welding quality detection method according to claim 11, characterized in that, The gas parameters include the pressure of the gas. The steps of detecting the gas parameters in the air flow channel and obtaining the penetration depth of the weld seam according to the gas parameters and the initial gas parameters measured when not welded include: Detect the pressure of the gas at the first opening, and obtain the penetration depth of the weld seam according to the pressure, the initial pressure and the cross-sectional area of the first sub-channel; Wherein, the initial pressure is the pressure measured at the first opening when the output pole and the conductive connecting piece are not welded, and the cross-sectional area of the first sub-channel is the cross-sectional area of the first sub-channel when the output pole and the conductive connecting piece are not welded.

13. The welding quality detection method according to claim 11, characterized in that, The gas parameters include the flow rate of the gas. The steps of detecting the gas parameters in the air flow channel and obtaining the penetration depth of the weld seam according to the gas parameters and the initial gas parameters measured when not welded include: Detect the flow rate of the gas at the second opening, and obtain the penetration depth of the weld seam according to the flow rate of the gas, the initial flow rate and the cross-sectional area of the first sub-channel; Wherein, the initial flow rate is the flow rate measured at the second opening when the output pole and the conductive connecting piece are not welded, and the cross-sectional area of the first sub-channel is the cross-sectional area of the first sub-channel when the output pole and the conductive connecting piece are not welded.

14. The welding quality detection method according to any one of claims 11 to 13, characterized in that, The number of the through holes and the air flow channels is multiple and equal. The multiple air flow channels are arranged separately from each other, and the multiple through holes are in one-to-one correspondence and communication with the first openings of the multiple air flow channels. The step of introducing gas into the through hole so that the gas enters the air flow channel from the first opening includes: Introduce gas into each of the through holes respectively so that the gas enters each of the air flow channels from the corresponding first opening; The steps of detecting the gas parameters in the air flow channel and obtaining the penetration depth of the weld seam according to the gas parameters and the initial gas parameters measured when not welded include: Detect the gas parameters in the multiple air flow channels respectively, and obtain the penetration depth of the weld seam according to the multiple gas parameters.

15. A battery device, characterized in that, Comprising: A box body, which is provided with a receiving cavity; A battery cell, which is arranged in the receiving cavity, and the battery cell is the battery cell according to any one of claims 1 to 10; A conductive connecting piece, which is provided with a through hole communicating with the first opening, and the conductive connecting piece is welded to the top surface of the output pole of the battery cell, and the formed weld seam extends into the air flow channel, and the weld seam is arranged at an interval from the first opening; A sampling piece; A battery management module, and the sampling piece is electrically connected to the conductive connecting piece and the battery management module.

16. An electrical device, characterized in that, The electrical equipment includes an equipment body and the battery device according to claim 15, and the battery device is arranged on the equipment body.

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