Battery cells, batteries, electrical devices, welding methods and equipment

Abstract

This application relates to the field of battery technology and discloses a battery cell, a battery, an electrical device, a welding method, and equipment. The battery cell includes: an end cap, the end cap including an injection hole; and a sealing element, the sealing element being sealed to the injection hole. A first welding segment and a second welding segment are formed between the sealing element and the end cap. At least a portion of the first welding segment and at least a portion of the second welding segment together form an annular weld of the sealing element. The first welding segment is formed by continuous laser, and the second welding segment is formed by pulsed laser. Because this application combines the high welding rate of continuous laser and the high yield of pulsed laser, it can avoid the problems of low welding speed and low yield during the welding process of the sealing element, and helps to improve the welding rate and welding yield of the sealing element.

Description

Technical Field

[0001] This application relates to the field of battery technology, specifically to a battery cell, a battery, an electrical device, a welding method, and equipment. Background Technology

[0002] Currently, battery cell seals are typically formed in a single welding process using pulsed laser or continuous laser. However, pulsed laser welding has a low welding speed, which limits production capacity. Continuous laser welding, due to the heat effect, causes residual electrolyte inside to vaporize and escape from the termination point, resulting in numerous termination pore defects. Consequently, the welding yield of the seals cannot meet the requirements. Summary of the Invention

[0003] In view of the above problems, this application provides a battery cell, a battery, an electrical device, a welding method, and an apparatus, which aim to solve the problems of low welding speed and low yield in the existing sealing welding process.

[0004] In a first aspect, this application provides a battery cell, comprising: End cap, the end cap including a liquid injection hole; A sealing element, wherein the sealing element is sealingly connected to the injection hole, The sealing element and the end cap are provided with a first welding segment and a second welding segment, at least a portion of the first welding segment and at least a portion of the second welding segment together form an annular weld around the sealing element, the first welding segment is formed by continuous laser and the second welding segment is formed by pulsed laser.

[0005] In the technical solution of this application embodiment, a first welding segment and a second welding segment are formed between the seal and the end cap. The first welding segment is formed by a continuous laser emitting a continuous laser, and the second welding segment is formed by a pulsed laser emitting a pulsed laser. This combines the high welding rate of the continuous laser and the high yield of the pulsed laser, thereby avoiding the problems of low welding speed and low yield during the welding process of the seal, and helping to improve the welding rate and welding yield of the seal.

[0006] In some embodiments, the second welding segment includes a head, a middle section, and a tail section connected in sequence, wherein the middle section is connected to the first welding segment to form the annular weld.

[0007] In the technical solution of this application embodiment, since the laser at the head and tail is unstable and the laser in the middle is stable during welding, the welding efficiency can be improved by setting the middle of the second welding segment to connect with the first welding segment to form an annular weld.

[0008] In some embodiments, the head and the tail are of equal length.

[0009] In the technical solution of this application embodiment, by setting the length of the head and the tail to be equal, the head and tail can be symmetrically set, thereby beautifying the circumferential weld.

[0010] In some embodiments, the head and / or the tail portion partially overlaps with the first welded segment.

[0011] In the technical solution of this application embodiment, by setting the head and / or tail of the second welding segment to partially overlap with the first welding segment, the sealing performance of the seal can be improved.

[0012] In some embodiments, the central dimension is not less than 1 mm.

[0013] In the technical solution of this application embodiment, by setting the middle dimension of the second welding segment to be not less than 1mm, sufficient area can be reserved for the discharge of electrolyte vapor, thus avoiding the formation of finishing defects.

[0014] In some embodiments, the length of the first welded segment in the annular weld is greater than the length of the second welded segment in the annular weld.

[0015] In the technical solution of this application embodiment, by setting the length of the first welding segment to be greater than the length of the second welding segment, it is possible to ensure that continuous laser welding is the main welding method and pulsed laser welding is the secondary welding method. Since the continuous laser welding rate is faster, the welding rate of the seal can be improved.

[0016] In some embodiments, the spacing between the weld points of the first welding segment is equal to the spacing between the weld points of the second welding segment.

[0017] In the technical solution of this application embodiment, by setting the spacing between the weld points of the first welding segment to be equal to the spacing between the weld points of the second welding segment, the appearance of the circumferential weld can be guaranteed to be consistent.

[0018] In some embodiments, the diameter of the weld joint in the first welding segment is equal to the diameter of the weld joint in the second welding segment.

[0019] In the technical solution of this application embodiment, by making the diameter of the weld point of the first welding segment equal to the diameter of the weld point of the second welding segment, the width of the circumferential weld can be ensured to be consistent.

[0020] Secondly, this application provides a battery, including the battery cell described in the above embodiments.

[0021] Thirdly, this application provides an electrical device including the battery in the above embodiments, the battery being used to provide electrical energy.

[0022] Fourthly, this application provides a welding method for welding a seal to a material, comprising: During the welding of the seal, a continuous laser is controlled to emit a continuous laser to form the first welded segment of the seal; After the continuous laser welding is completed, the pulsed laser is controlled to emit pulsed laser to form a second welded segment of the seal. At least a portion of the first welded segment and at least a portion of the second welded segment together form an annular weld around the seal.

[0023] In the technical solution of this application embodiment, the sealing component is welded in segments. The annular weld of the sealing component is formed by the first welding segment and the second welding segment together. The first welding segment is formed by a continuous laser emitting continuous laser light, and the second welding segment is formed by a pulsed laser emitting pulsed laser light. This can combine the high welding rate of continuous laser light and the high yield of pulsed laser light, thereby avoiding the problems of low welding speed and low yield during the welding process of the sealing component, and helping to improve the welding rate and welding yield of the sealing component.

[0024] In some embodiments, the welding method further includes: While controlling the continuous laser to emit continuous laser light to form the first welded segment of the seal, the pulsed laser is simultaneously controlled to emit pulsed laser light to form the second welded segment of the previous seal.

[0025] In the technical solution of this application embodiment, since the continuous laser is controlled to emit a continuous laser to form the first welding segment of the seal, the pulsed laser can be controlled to emit a pulsed laser to form the second welding segment of the previous seal at the same time, thereby improving the welding speed.

[0026] In some embodiments, the welding time of the first welding segment of the seal by the continuous laser is equal to the welding time of the second welding segment of the previous seal by the pulsed laser, thereby avoiding material buildup and increasing the welding speed.

[0027] In some embodiments, after the continuous laser welding is completed and before the pulsed laser welding is completed, the length of the unwelded area between the seal and the material is greater than or equal to 1 mm.

[0028] In the technical solution of this application embodiment, by setting the length of the unwelded area between the seal and the material to be greater than or equal to 1 mm, sufficient area can be reserved for the discharge of electrolyte vapor, thus avoiding the formation of finishing defects.

[0029] In some embodiments, the step of controlling a pulsed laser to emit a pulsed laser to form a second welded segment of the seal after the continuous laser welding is completed includes: After the continuous laser welding is completed, a pulsed laser is controlled to emit pulsed laser at preset intervals to form the second welded segment of the seal.

[0030] In the technical solution of this application embodiment, by setting the interval time between continuous laser welding and pulsed laser welding, sufficient time can be reserved for the electrolyte vapor to be discharged, thus avoiding the formation of finishing defects.

[0031] In some embodiments, the continuous laser is a modulated continuous laser, and the pulsed laser is a YAG pulsed laser.

[0032] In the technical solution of this application embodiment, by setting the continuous laser to a modulated continuous laser, the large spot formed by the modulated continuous laser can improve the tolerance of electrolyte contamination, and the dotted appearance formed by the modulated continuous laser is no different from the appearance of the weld seam of the subsequent YAG pulsed laser, thereby ensuring that the appearance of the circumferential weld seam is indistinguishable. In addition, while the modulated continuous laser is welding at high speed, it leaves a tailing vent hole to facilitate the discharge of electrolyte vapor and avoid the formation of tailing defects. By setting the pulsed laser to a YAG pulsed laser, the flatness and aesthetics of the tailing weld seam can be ensured.

[0033] In some embodiments, the ratio of the welding speed to the welding frequency of the continuous laser is equal to the ratio of the welding speed to the welding frequency of the pulsed laser.

[0034] In the technical solution of this application embodiment, by setting the stepping of the continuous laser and the pulsed laser to be consistent, it is possible to ensure that the spacing between the weld points of the first welding segment is equal to the spacing between the weld points of the second welding segment, thereby ensuring the consistent appearance of the circumferential weld.

[0035] In some embodiments, the single-point energy emitted by the continuous laser and the pulsed laser is equal.

[0036] In the technical solution of this application embodiment, by setting the single-point energy emitted by the continuous laser and the pulsed laser to be equal, it is possible to ensure that the diameter of the weld point of the first welding segment is equal to the diameter of the weld point of the second welding segment, thereby ensuring that the width of the first welding segment and the second welding segment is consistent.

[0037] Fifthly, this application provides a welding apparatus, the welding apparatus comprising: A platform for holding seals and materials; A welding platform is provided, which is correspondingly arranged with the platform. A continuous laser and a pulsed laser are respectively provided on the welding platform. The continuous laser is used to form a first welding segment between the seal and the material, and the pulsed laser is used to form a second welding segment between the seal and the material. At least a portion of the first welding segment and at least a portion of the second welding segment together form an annular weld around the seal.

[0038] In the technical solution of this application embodiment, by setting a continuous laser and a pulsed laser on the welding platform respectively, the continuous laser is used to form a first welding segment between the seal and the material, and the pulsed laser is used to form a second welding segment between the seal and the material. At least a portion of the first welding segment and at least a portion of the second welding segment together form an annular weld of the seal. This combines the high welding rate of the continuous laser and the high yield of the pulsed laser, thereby avoiding the problems of low welding speed and low yield during the welding process of the seal, and helping to improve the welding rate and welding yield of the seal.

[0039] In some embodiments, the stage is configured to be rotatable to allow the seal and the material to switch between the continuous laser and the pulsed laser.

[0040] In the technical solution of this application embodiment, the stage is configured to be rotatable, thereby ensuring that the pulsed laser continues welding after the continuous laser welding is completed.

[0041] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, the following are specific embodiments of this application. Attached Figure Description

[0042] Figure 1 This is a schematic diagram of the vehicle structure according to some embodiments of this application; Figure 2 This is an exploded structural diagram of a battery according to some embodiments of this application; Figure 3 This is an exploded structural diagram of a battery cell according to some embodiments of this application; Figure 4 This is an exploded structural diagram of the end cap of some embodiments of this application; Figure 5 This is a schematic diagram of the structure of the circumferential weld in some embodiments of this application; Figure 6 This is a schematic diagram of the head, middle, and tail of the second welding segment in some embodiments of this application; Figure 7This is a structural schematic diagram of the first welding angle and the second welding angle in some embodiments of this application; Figure 8 This is a schematic flowchart of a welding method proposed in some embodiments of this application; Figure 9 This is a schematic diagram of a welding apparatus for a welding method proposed in some embodiments of this application.

[0043] The reference numerals in the detailed embodiments are as follows: 1000 vehicles; Battery 100, controller 200, motor 300; Box 10, Part 11, Part 2 12; Battery cell 20, end cap 21, electrode terminal 21a, housing 22, electrode assembly 23, tab 23a; 31. Glue nail; 32. Injection hole; 33. Receiving groove; 40. Seal. First welding section 50, second welding section 60; Head 61, middle 62, tail 63; First welding angle Second welding angle ; 70 platform, 80 welding platform, 81 unloading assembly, 82 loading assembly, 83 laser cleaning assembly, 84 nail mounting assembly, 85 pre-welding assembly, 86 continuous laser, 87 pulsed laser, 88 CCD detection assembly. Detailed Implementation

[0044] The embodiments of the technical solution of this application will now be described in detail with reference to the accompanying drawings. These embodiments are only used to more clearly illustrate the technical solution of this application and are therefore merely examples, and should not be used to limit the scope of protection of this application.

[0045] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms “comprising” and “having”, and any variations thereof, in the specification, claims, and foregoing description of the drawings are intended to cover non-exclusive inclusion.

[0046] In the description of the embodiments of this application, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly defined.

[0047] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0048] In the description of the embodiments in this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.

[0049] In the description of the embodiments of this application, the term "multiple" refers to two or more (including two), similarly, "multiple sets" refers to two or more (including two sets), and "multiple pieces" refers to two or more (including two pieces).

[0050] In the description of the embodiments of this application, the technical terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of this application and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of this application.

[0051] In the description of the embodiments of this application, unless otherwise expressly specified and limited, technical terms such as "installation," "connection," "joining," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of this application according to the specific circumstances. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0052] Currently, judging from market trends, battery applications are becoming increasingly widespread. Batteries are not only used in energy storage systems such as hydropower, thermal power, wind power, and solar power plants, but also extensively in electric vehicles such as electric bicycles, electric motorcycles, and electric cars, as well as in military equipment and aerospace. With the continuous expansion of battery applications, market demand is also constantly increasing.

[0053] The inventors noted that the sealing components of battery cells are typically formed by one-time welding using pulsed laser or continuous laser. Pulsed laser welding has advantages such as mature technology and high yield; however, its low welding speed limits battery production capacity, and the low cycle time of pulsed laser welding requires more welding equipment to meet production demands, resulting in poor consistency of weld penetration. Continuous laser welding has the advantage of high welding speed; however, its low tolerance to electrolyte makes it prone to defects such as pinholes / bursts. Furthermore, due to the heat effect of welding, residual electrolyte inside the continuous laser weld forms vapor, which is discharged from the termination point, creating numerous termination pore defects, and the welding yield cannot meet requirements.

[0054] To address the issues of low welding speed and low yield in existing sealing component welding processes, the applicant has discovered that the sealing components of battery cells can be welded in segments. A first welding segment and a second welding segment are formed between the sealing component and the end cap. At least a portion of the first welding segment and at least a portion of the second welding segment together enclose and form an annular weld seam of the sealing component. The first welding segment is formed by continuous laser welding, and the second welding segment is formed by pulsed laser welding. This combines the high welding speed of continuous laser welding with the high yield of pulsed laser welding, thereby avoiding the problems of low welding speed and low yield in sealing component welding processes and helping to improve the welding speed and welding yield of the sealing components.

[0055] The battery cells disclosed in this application can be used in electrical devices that use batteries as a power source or in various energy storage systems that use batteries as energy storage elements. Electrical devices can be, but are not limited to, mobile phones, tablets, laptops, electric toys, power tools, electric vehicles, electric cars, ships, spacecraft, etc. Electric toys can include stationary or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, etc. Spacecraft can include airplanes, rockets, space shuttles, and spacecraft, etc.

[0056] For ease of explanation, the following embodiments will be described using a vehicle 1000 as an example of an electrical device according to an embodiment of this application.

[0057] Please refer to Figure 1 , Figure 1This is a schematic diagram of the structure of a vehicle 1000 provided in some embodiments of this application. The vehicle 1000 can be a gasoline-powered vehicle, a natural gas-powered vehicle, or a new energy vehicle. New energy vehicles can be pure electric vehicles, hybrid electric vehicles, or range-extended electric vehicles, etc. A battery 100 is disposed inside the vehicle 1000, and the battery 100 can be located at the bottom, front, or rear of the vehicle 1000. The battery 100 can be used to power the vehicle 1000; for example, the battery 100 can serve as the operating power source for the vehicle 1000. The vehicle 1000 may also include a controller 200 and a motor 300. The controller 200 is used to control the battery 100 to supply power to the motor 300, for example, to meet the power needs of the vehicle 1000 during startup, navigation, and driving.

[0058] In some embodiments of this application, the battery 100 can not only serve as the operating power source for the vehicle 1000, but also as the driving power source for the vehicle 1000, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1000.

[0059] Please refer to Figure 2 , Figure 2 This is an exploded view of a battery 100 provided in some embodiments of this application. The battery 100 includes a housing 10 and a battery cell 20, with the battery cell 20 housed within the housing 10. The housing 10 provides a space for the battery cell 20 and can have various structures. In some embodiments, the housing 10 may include a first portion 11 and a second portion 12, which overlap each other, jointly defining a space for accommodating the battery cell 20. The second portion 12 may be a hollow structure with one open end, and the first portion 11 may be a plate-like structure, covering the open side of the second portion 12 so that the first portion 11 and the second portion 12 jointly define the space; alternatively, the first portion 11 and the second portion 12 may both be hollow structures with one open side, with the open side of the first portion 11 covering the open side of the second portion 12. Of course, the housing 10 formed by the first portion 11 and the second portion 12 can have various shapes, such as a cylinder, a cuboid, etc.

[0060] In battery 100, there can be multiple battery cells 20, which can be connected in series, parallel, or in a mixed manner. A mixed connection means that multiple battery cells 20 are connected in both series and parallel configurations. Multiple battery cells 20 can be directly connected in series, parallel, or in a mixed manner, and then the entire assembly of the multiple battery cells 20 is housed within the housing 10. Alternatively, battery 100 can also be composed of multiple battery cells 20 first connected in series, parallel, or in a mixed manner to form a battery module, and then multiple battery modules are connected in series, parallel, or in a mixed manner to form a whole, which is also housed within the housing 10. Battery 100 may also include other structures; for example, it may include a busbar component for electrical connection between the multiple battery cells 20.

[0061] 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 to these. The battery cell 20 can be cylindrical, flat, cuboid, or other shapes.

[0062] Please refer to Figure 3 , Figure 3 This is an exploded structural diagram of a battery cell 20 provided in some embodiments of this application. The battery cell 20 refers to the smallest unit that makes up a battery. For example... Figure 3 The battery cell 20 includes an end cap 21, a housing 22, an electrode assembly 23, and other functional components.

[0063] End cap 21 refers to a component that covers the opening of housing 22 to isolate the internal environment of battery cell 20 from the external environment. The shape of end cap 21 can be adapted to the shape of housing 22 to fit it. Optionally, end cap 21 can be made of a material with certain hardness and strength (such as aluminum alloy), so that end cap 21 is not easily deformed under pressure and impact, allowing battery cell 20 to have higher structural strength and improved safety performance. Functional components such as electrode terminals 21a can be provided on end cap 21. Electrode terminals 21a can be used for electrical connection with electrode assembly 23 to output or input electrical energy to battery cell 20. In some embodiments, end cap 21 can also be provided with a pressure relief mechanism for releasing internal pressure when the internal pressure or temperature of battery cell 20 reaches a threshold. The material of end cap 21 can also be various, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc., and this application embodiment does not impose special limitations on this. In some embodiments, an insulating element may be provided on the inner side of the end cap 21. The insulating element can be used to isolate the electrical connection components within the housing 22 from the end cap 21 to reduce the risk of short circuits. For example, the insulating element may be made of plastic, rubber, etc.

[0064] The housing 22 is a component used to cooperate with the end cap 21 to form the internal environment of the battery cell 20. This internal environment can accommodate the electrode assembly 23, electrolyte, and other components. The housing 22 and the end cap 21 can be independent components. An opening can be provided on the housing 22, and the end cap 21 can be used to close the opening to form the internal environment of the battery cell 20. Alternatively, the end cap 21 and the housing 22 can be integrated. Specifically, the end cap 21 and the housing 22 can form a common connecting surface before other components are inserted into the housing. When it is necessary to encapsulate the interior of the housing 22, the end cap 21 closes the housing 22. The housing 22 can be of various shapes and sizes, such as cuboid, cylindrical, hexagonal prism, etc. Specifically, the shape of the housing 22 can be determined according to the specific shape and size of the electrode assembly 23. The material of the housing 22 can be various, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc. This application embodiment does not impose any special limitations on this.

[0065] Electrode assembly 23 is the component in the battery cell 20 where electrochemical reactions occur. The casing 22 may contain one or more electrode assemblies 23. The electrode assembly 23 is mainly formed by winding or stacking positive and negative electrode sheets, and typically a separator is provided between the positive and negative electrode sheets. The portions of the positive and negative electrode sheets containing active material constitute the main body of the cell assembly, while the portions of the positive and negative electrode sheets without active material each constitute a tab 23a. The positive and negative tabs may be located together at one end of the main body or separately at both ends of the main body. During the charging and discharging process of the battery, the positive and negative active materials react with the electrolyte, and the tabs 23a connect to the electrode terminals to form a current loop.

[0066] According to some embodiments of this application, refer to Figure 4 The end cap 21 has a mounting surface for installing the seal 40. An injection hole 32 is provided on the end cap 21. To facilitate sealing the injection hole 32, a receiving groove 33 is recessed on the mounting surface of the end cap 21. The injection hole 32 is located at the bottom of the receiving groove 33, so that one end of the injection hole 32 connects to the receiving groove 33, and the other end extends to the inner surface of the end cap 21. During installation, a rubber nail 31 is inserted into the injection hole 32 to seal it. The seal 40 is located within the receiving groove 33, which restricts the radial movement of the seal 40. The seal 40 is then welded to the end cap 21.

[0067] The general outline of existing seals 40 is typically frustoconical, such as Figure 4As shown, in a cross-section parallel to the axial direction of the seal 40, the upper end of the rubber pin 31 mates with the bottom surface of the seal 40; the side wall of the receiving groove 33 is inclined; the outer ring wall of the seal 40 mates with the side wall of the receiving groove 33; and the end of the outer ring wall of the seal 40 away from the rubber pin 31 is close to the inner wall of the receiving groove 33, so that the seal 40 can be used to fill the receiving groove 33; the top surface of the seal 40 is flush with the top surface of the end cap 21, or the top surface of the seal 40 is slightly higher than the top surface of the end cap 21. The circular joint between the seal 40 and the end cap 21 is welded to fix the seal 40 to the end cap 21.

[0068] Taking the use of a laser welding device as a welding assembly as an example, when welding is performed using the welding assembly, the welding assembly emits a high-energy laser towards the joint between the seal 40 and the end cap 21. Under the action of the laser, a liquid metal portion with a certain shape is formed at the joint between the seal 40 and the end cap 21. This liquid metal portion is called the weld pool. During the welding process, as the welding assembly moves, the metal at the tail end of the weld pool cools and crystallizes to form a weld.

[0069] When the existing seal 40 is welded using a pulsed laser, the low welding speed of the pulsed laser limits the battery production capacity. Furthermore, the low cycle time of the pulsed laser requires a large number of welding devices, resulting in poor consistency of the penetration depth.

[0070] When the existing seal 40 is welded using a continuous laser, a large amount of heat is generated in the weld pool as the continuous laser moves along a preset trajectory. The electrolyte remaining in the injection hole 32 decomposes into gas under the high heat of the high-energy laser beam. After the seal 40 is welded, a sealed cavity is formed between the seal 40 and the inner wall of the receiving groove 33. The gas remains in the sealed cavity between the seal 40 and the receiving groove 33, resulting in excessively high gas pressure in the sealed cavity. High-pressure gas is prone to forming pores at the beginning and end of the weld. Since the pores connect to the sealed cavity, the receiving groove 33 cannot be completely sealed, which leads to product defects in the end cap 21 and the welding yield of the product cannot meet the requirements.

[0071] This application addresses the problems of low welding speed and low yield in existing sealing welding processes by proposing a new battery cell. Please refer to [reference needed]. Figure 4 and Figure 5 In this example, the battery cell 20 includes: an end cap 21, which includes an injection hole 32; and a seal 40, which is sealed to the injection hole 32. A first weld segment 50 and a second weld segment 60 are formed between the seal 40 and the end cap 21. At least a portion of the first weld segment 50 and at least a portion of the second weld segment 60 together form an annular weld around the seal 40. The first weld segment 50 is formed by continuous laser, and the second weld segment 60 is formed by pulsed laser.

[0072] By segmenting the sealing element 40 of the battery cell 20, a first welding segment 50 and a second welding segment 60 are formed between the sealing element 40 and the end cap 21. At least a portion of the first welding segment 50 and at least a portion of the second welding segment 60 together form an annular weld of the sealing element 40. The first welding segment 50 is formed by continuous laser, and the second welding segment 60 is formed by pulsed laser. This combines the high welding rate of continuous laser and the high yield of pulsed laser, thereby avoiding the problems of low welding speed and low yield during the welding of the sealing element 40, and helping to improve the welding rate and welding yield of the sealing element 40.

[0073] Optionally, according to some embodiments of this application, please refer to Figure 6 The second welding segment 60 includes a head 61, a middle section 62 and a tail section connected in sequence. The middle section 62 is connected to the first welding segment 50 to form an annular weld.

[0074] In this embodiment, the second welding segment 60 is divided into a head 61, a middle part 62 and a tail part 63 connected in sequence according to the formation time of the second welding segment 60.

[0075] Since the laser at the head 61 and tail 63 is unstable during welding, while the laser at the middle 62 is stable, the welding yield can be improved by connecting the middle 62 of the second welding segment 60 with the first welding segment 50 to form a circumferential weld.

[0076] Optionally, according to some embodiments of this application, please refer to Figure 6 The head 61 and the tail 63 are of equal length, so that the head 61 and the tail 63 can be symmetrically arranged to beautify the circumferential weld.

[0077] Optionally, according to some embodiments of this application, please refer to Figure 7 The head 61 and / or tail 63 partially overlap with the first welded segment 50.

[0078] Specifically, the overlap angle can be based on the first welding angle corresponding to the first welding segment 50. The second welding angle corresponding to the second welding segment 60 Determine, for example, the first welding angle corresponding to the first welding segment 50. The second welding angle is 340°, corresponding to the second welding segment 60. When the angle is 40°, the coincidence angle = 340° + 40° - 360° = 20°.

[0079] First welding angle The second welding angle can be any value within [270°, 340°]. The angle can be any value within [40°, 90°]. To ensure the sealing performance of the seal 40 while simultaneously achieving the goal of at least a portion of the first weld segment 50 and at least a portion of the second weld segment 60 jointly enclosing the annular weld of the seal 40, the first weld segment 50 and the second weld segment 60 must overlap by 10° or more. Therefore, the first welding angle... With the second welding angle The sum of the angles is not less than 370°.

[0080] By setting the head 61 and / or tail 63 of the second welding section 60 to partially overlap with the first welding section 50, the sealing performance of the seal 40 can be improved.

[0081] Optionally, according to some embodiments of this application, please refer to Figure 6 The central 62 dimension is not less than 1mm.

[0082] By setting the size of the middle part 62 of the second welding section 60 to be no less than 1mm, sufficient area can be reserved for the discharge of electrolyte vapor during the welding process, thus avoiding the formation of finishing defects.

[0083] Optionally, according to some embodiments of this application, please refer to Figure 5 The length of the first welded segment 50 in the circumferential weld is greater than the length of the second welded segment 60 in the circumferential weld.

[0084] By setting the length of the first welding segment 50 to be greater than the length of the second welding segment 60, it is possible to ensure that continuous laser welding is the primary welding method and pulsed laser welding is the secondary welding method. Since the continuous laser welding rate is faster, the welding rate of the seal 40 can be improved.

[0085] Optionally, according to some embodiments of this application, please refer to Figure 5 The spacing between the weld points of the first welding segment 50 is equal to the spacing between the weld points of the second welding segment 60.

[0086] The continuous laser can be a modulated continuous laser, which can be modulated into a pulse mode so that the first continuous welding segment 50 forms a dotted weld appearance, which is consistent with the appearance of the second welding segment 60 formed by the subsequent pulsed laser. The pulsed laser can be a YAG pulsed laser, which can ensure the flatness and aesthetics of the final weld.

[0087] To ensure consistent appearance of the spot welds, the spacing between welds in the first welding segment 50 must be equal to the spacing between welds in the second welding segment 60. This means that the continuous laser emitting continuous laser light and the pulsed laser emitting pulsed laser light must have perfectly synchronized stepping. In the formula, For the welding speed of a continuous laser, The welding frequency of the continuous laser. The welding speed of the pulsed laser. This refers to the welding frequency of the pulsed laser.

[0088] To ensure that the first welding segment 50 and the second welding segment 60 partially overlap, the stepping of the continuous laser and the pulsed laser must not exceed a preset stepping value. The preset step can be set in advance.

[0089] By setting the spacing between the weld points of the first welding segment 50 to be equal to the spacing between the weld points of the second welding segment 60, the appearance of the circumferential weld can be ensured to be consistent.

[0090] Optionally, according to some embodiments of this application, please refer to Figure 5 The diameter of the weld point in the first welding segment 50 is equal to the diameter of the weld point in the second welding segment 60.

[0091] To ensure that the widths of the first welding segment 50 and the second welding segment 60 are consistent, in this embodiment, it is necessary to ensure that the single-point energy emitted by the continuous laser and the pulsed laser is the same. That is: In the formula, This represents the peak power of the continuous laser. This represents the pulse width corresponding to the peak power of the continuous-wave laser. This represents the peak power of the pulsed laser. This represents the pulse width corresponding to the peak power of the pulsed laser.

[0092] According to some embodiments of this application, refer to Figure 8 , Figure 8 This is a schematic flowchart of a welding method proposed according to some embodiments of this application.

[0093] In this embodiment, the welding method is used to weld the seal 40 to the material, including: Step S10: During the welding of the seal 40, the continuous laser is controlled to emit a continuous laser to form the first welded segment 50 of the seal 40.

[0094] According to some embodiments of this application, optionally, while controlling the continuous laser to emit continuous laser light to form the first weld segment 50 of the seal 40, the pulsed laser is simultaneously controlled to emit pulsed laser light to form the second weld segment 60 of the previous seal 40.

[0095] By controlling a continuous laser to emit a continuous laser to form the first welding segment 50 of the seal 40, a pulsed laser can be simultaneously controlled to emit a pulsed laser to form the second welding segment 60 of the previous seal 40, thereby increasing the welding speed.

[0096] According to some embodiments of this application, optionally, the welding time of the continuous laser welding the first welding segment of the seal is equal to the welding time of the pulsed laser welding the second welding segment of the previous seal.

[0097] While controlling the continuous laser to emit continuous laser light to form the first weld segment 50 of the seal 40, a pulsed laser is also simultaneously controlled to emit pulsed laser light to form the second weld segment 60 of the previous seal 40. Therefore, to avoid material buildup during welding, in this embodiment, it is also necessary to ensure that the welding time of the continuous laser welding the first weld segment 50 of the seal 40 is equal to the welding time of the pulsed laser welding the second weld segment 60 of the previous seal 40. That is... In the formula, This is the sum of the acceleration and deceleration times of the continuous laser, where the acceleration time is the time it takes for the welding speed of the continuous laser to increase from zero to the corresponding stable welding speed, and the deceleration time is the time it takes for the welding speed of the continuous laser to decrease from the corresponding stable welding speed to zero. The stable welding speed is the speed at which the laser emits laser light and welding begins, for example, the corresponding stable welding speed of the continuous laser is 80 mm / s. The first welding angle corresponds to the first welding segment 50. The welding trajectory radius of seal 40. For the welding speed of a continuous laser, This is the sum of the acceleration and deceleration times of the pulsed laser, where the acceleration time is the time it takes for the pulsed laser welding speed to increase from zero to the corresponding stable welding speed, and the deceleration time is the time it takes for the continuous laser welding speed to decrease from the corresponding stable welding speed to zero. The corresponding stable welding speed of the pulsed laser is 7 mm / s. This refers to the second welding angle corresponding to the second welding segment 60. The welding speed of the pulsed laser. .

[0098] Step S20: After the continuous laser welding is completed, the pulse laser is controlled to emit pulse laser to form the second welding segment 60 of the seal 40. At least a portion of the first welding segment 50 and at least a portion of the second welding segment 60 together form an annular weld around the seal 40.

[0099] In this embodiment, during the welding of the seal 40, a continuous laser is controlled to emit a continuous laser to form a first welding segment 50 of the seal 40. After the continuous laser welding is completed, a pulsed laser is controlled to emit a pulsed laser to form a second welding segment 60 of the seal 40. At least a portion of the first welding segment 50 and at least a portion of the second welding segment 60 together enclose and form an annular weld of the seal 40. Since the seal 40 is welded in segments in this embodiment, the annular weld of the seal 40 is formed by the first welding segment 50 and the second welding segment 60. The first welding segment 50 is formed by the continuous laser, and the second welding segment 60 is formed by the pulsed laser. This combines the high welding rate of the continuous laser and the high yield of the pulsed laser, thereby avoiding the problems of low welding speed and low yield during the welding of the seal 40, and helping to improve the welding rate and welding yield of the seal 40.

[0100] According to some embodiments of this application, optionally, after the continuous laser welding is completed and before the pulsed laser welding is completed, the length of the unwelded area between the seal 40 and the material is greater than or equal to 1 mm.

[0101] By setting the length of the unwelded area between the seal 40 and the material to be greater than or equal to 1 mm, sufficient area can be reserved for the discharge of electrolyte vapor, thus avoiding the formation of finishing defects.

[0102] According to some embodiments of this application, optionally, after the continuous laser welding is completed, a pulsed laser is controlled to emit pulsed laser at preset intervals to form a second welded segment 60 of the seal 40.

[0103] By setting the interval between continuous laser welding and pulsed laser welding, sufficient time can be allowed for electrolyte vapor to escape, thus preventing the formation of finishing defects. The interval can be preset.

[0104] According to some embodiments of this application, optionally, the continuous laser is a modulated continuous laser, and the pulsed laser is a YAG pulsed laser.

[0105] By setting the continuous laser to a modulated continuous laser, the large spot size formed by the modulated continuous laser can improve the tolerance of electrolyte contamination. Furthermore, the dotted appearance formed by the modulated continuous laser is indistinguishable from the appearance of the weld seam after the subsequent YAG pulsed laser welding, thus ensuring that the appearance of the circumferential weld seam is indistinguishable. In addition, the modulated continuous laser leaves tail vents during high-speed welding, which facilitates the discharge of electrolyte vapor and avoids the formation of tail defects. By setting the pulsed laser to a YAG pulsed laser, the smoothness and aesthetics of the tail weld seam can be ensured.

[0106] According to some embodiments of this application, optionally, the ratio of the welding speed to the welding frequency of the continuous laser is equal to the ratio of the welding speed to the welding frequency of the pulsed laser.

[0107] To ensure consistent appearance of the spot welds, the spacing between welds in the first welding segment 50 must be equal to the spacing between welds in the second welding segment 60. This means that the continuous laser emitting continuous laser light and the pulsed laser emitting pulsed laser light must have perfectly synchronized stepping. In the formula, For the welding speed of a continuous laser, The welding frequency of the continuous laser. The welding speed of the pulsed laser. This refers to the welding frequency of the pulsed laser.

[0108] According to some embodiments of this application, optionally, the continuous laser emits the same single-point energy as the pulsed laser.

[0109] To ensure that the widths of the first welding segment 50 and the second welding segment 60 are consistent, in this embodiment, it is necessary to ensure that the single-point energy emitted by the continuous laser and the pulsed laser is the same. That is: In the formula, This represents the peak power of the continuous laser. This represents the pulse width corresponding to the peak power of the continuous-wave laser. This represents the peak power of the pulsed laser. This represents the pulse width corresponding to the peak power of the pulsed laser.

[0110] According to some embodiments of this application, refer to Figure 9 , Figure 9 This is a schematic diagram of a welding device proposed according to some embodiments of this application.

[0111] In this embodiment, the welding equipment includes: a stage 70 for placing the sealing element 40 and the material; and a welding platform 80, which is correspondingly arranged with the stage 70. A continuous laser 86 and a pulsed laser 87 are respectively arranged on the welding platform 80. The continuous laser 86 is used to form a first welding segment 50 between the sealing element 40 and the material, and the pulsed laser 87 is used to form a second welding segment 60 between the sealing element 40 and the material. At least a portion of the first welding segment 50 and at least a portion of the second welding segment 60 together enclose and form an annular weld of the sealing element 40.

[0112] The welding platform 80 and the carrier 70 can be configured such that the position of the carrier 70 where the seal 40 and the material are placed corresponds to the position of the welding platform 80.

[0113] The welding platform 80 can also be equipped with a material unloading component 81, a material loading component 82, a laser cleaning component 83, a nail mounting component 84, a pre-welding component 85, and a CCD inspection component 88.

[0114] During the welding process of the seal 40, after the battery cell is loaded / laser cleaned / nailed, the continuous laser 86 begins welding the first welding segment 50 of the Nth battery cell seal 40. At the same time, the pulsed laser 87 of the next station is simultaneously welding the second welding segment 60 of the (N-1)th battery cell seal 40. By setting the welding angle and welding speed, the cycle time can be equalized (i.e., the welding time of the continuous laser 86 is equal to the welding time of the pulsed laser 87). In the formula, This is the sum of the acceleration and deceleration times of the continuous laser, where the acceleration time is the time it takes for the welding speed of the continuous laser to increase from zero to the corresponding stable welding speed, and the deceleration time is the time it takes for the welding speed of the continuous laser to decrease from the corresponding stable welding speed to zero. The stable welding speed is the speed at which the laser emits laser light and welding begins, for example, the corresponding stable welding speed of the continuous laser is 80 mm / s. The first welding angle corresponds to the first welding segment 50. The welding trajectory radius of seal 40. For the welding speed of a continuous laser, This is the sum of the acceleration and deceleration times of the pulsed laser, where the acceleration time is the time it takes for the pulsed laser welding speed to increase from zero to the corresponding stable welding speed, and the deceleration time is the time it takes for the continuous laser welding speed to decrease from the corresponding stable welding speed to zero. The corresponding stable welding speed of the pulsed laser is 7 mm / s. This refers to the second welding angle corresponding to the second welding segment 60. The welding speed of the pulsed laser. .

[0115] When the continuous laser 86 begins welding the first welding segment 50 of the seal 40 of the first battery cell, since there is no seal 40 on the stage 70 corresponding to the pulse laser 87 in the next station, it is necessary to keep the pulse laser 87 stationary to avoid damage to the pulse laser 87 and protect the equipment. When the pulse laser 87 begins welding the second welding segment 60 of the seal 40 of the last battery cell, since there is no seal 40 on the stage 70 corresponding to the continuous laser 86 in the previous station, it is necessary to keep the continuous laser 86 stationary to avoid damage to the continuous laser 86 and protect the equipment.

[0116] By setting a continuous laser 86 and a pulsed laser 87 on the welding platform 80, the continuous laser 86 is used to form a first welding segment 50 between the seal 40 and the material, and the pulsed laser 87 is used to form a second welding segment 60 between the seal 40 and the material. At least a portion of the first welding segment 50 and at least a portion of the second welding segment 60 together form an annular weld seam of the seal 40. This combines the high welding rate of the continuous laser and the high yield of the pulsed laser, thereby avoiding the problems of low welding speed and low yield during the welding of the seal 40, and helping to improve the welding rate and welding yield of the seal 40.

[0117] According to some embodiments of this application, the stage 70 is optionally configured to be rotatable so that the seal 40 and the material are switched between the continuous laser 86 and the pulsed laser 87.

[0118] After the continuous laser 86 finishes welding the first welding segment 50 of the Nth cell seal 40, the stage 70 rotates so that the Nth cell seal 40 is aligned with the position of the pulsed laser 87. The pulsed laser 87 continues to weld the second welding segment 60 of the Nth cell seal 40. The rotation time of the stage 70 allows residual electrolyte vapor in the seal 40 to be discharged, thereby avoiding the formation of end-of-pipe defects.

[0119] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and not to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. These modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application, and they should all be covered within the scope of the claims and specification of this application. In particular, as long as there is no structural conflict, the various technical features mentioned in the embodiments can be combined in any way. This application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A single battery cell, comprising: End cap, the end cap including a liquid injection hole; A sealing element, wherein the sealing element is sealingly connected to the injection hole, The sealing element and the end cap are formed by a first welding segment and a second welding segment. At least a portion of the first welding segment and at least a portion of the second welding segment together form an annular weld around the sealing element. The first welding segment is formed by continuous laser, and the second welding segment is formed by pulsed laser. The second welding segment is divided into a head, a middle and a tail in sequence according to the formation time of the second welding segment. The middle part is connected to the first welding segment to form the annular weld. The head and the tail part partially overlap with the first welding segment. The continuous laser welding leaves a tail hole for electrolyte discharge. After the continuous laser welding is completed, pulsed laser welding is performed at a preset time interval. The preset time is longer than the time for the electrolyte vapor to be discharged.

2. The battery cell as described in claim 1, wherein, The head and the tail are of equal length.

3. The battery cell as described in claim 1 or 2, wherein, The central dimension is not less than 1mm.

4. The battery cell as described in claim 1 or 2, wherein, The length of the first welded segment in the annular weld is greater than the length of the second welded segment in the annular weld.

5. The battery cell as described in claim 1 or 2, wherein, The spacing between the weld points in the first welding segment is equal to the spacing between the weld points in the second welding segment.

6. The battery cell as described in claim 1 or 2, wherein, The diameter of the weld joint in the first welding segment is equal to the diameter of the weld joint in the second welding segment.

7. A battery comprising a battery cell according to any one of claims 1 to 6.

8. An electrical device comprising the battery of claim 7, the battery being used to provide electrical energy.

9. A welding method for welding a seal to a material, comprising: During the welding of the seal, a continuous laser is controlled to emit a continuous laser to form the first welded segment of the seal; After the continuous laser welding is completed, the pulsed laser is controlled to emit pulsed laser to form the second welding segment of the seal. At least a portion of the first welding segment and at least a portion of the second welding segment together form an annular weld around the seal. The second welding segment is divided into a head, a middle and a tail in sequence according to the formation time of the second welding segment. The middle segment is connected to the first welding segment to form the annular weld. The head and the tail partially overlap with the first welding segment. The continuous laser leaves a tail hole for electrolyte discharge during welding. Pulsed laser welding is performed at a preset time interval after the continuous laser welding is completed. The preset time is longer than the time for the electrolyte vapor to be discharged.

10. The welding method as described in claim 9, wherein, The welding method further includes: While controlling the continuous laser to emit continuous laser light to form the first weld segment of the seal, the pulsed laser is simultaneously controlled to emit pulsed laser light to form the second weld segment of the previous seal.

11. The welding method as described in claim 10, wherein, The welding time for the first weld segment of the seal using the continuous laser is equal to the welding time for the second weld segment of the previous seal using the pulsed laser.

12. The welding method according to any one of claims 9 to 11, wherein, After the continuous laser welding is completed and before the pulsed laser welding is completed, the length of the unwelded area between the seal and the material is greater than or equal to 1 mm.

13. The welding method according to any one of claims 9 to 11, wherein, The step of controlling a pulsed laser to emit pulsed laser light to form a second welded segment of the seal after the continuous laser welding is completed includes: After the continuous laser welding is completed, a pulsed laser is controlled to emit pulsed laser at preset intervals to form the second welded segment of the seal.

14. The welding method according to any one of claims 9 to 11, wherein, The continuous laser is a modulated continuous laser, and the pulsed laser is a YAG pulsed laser.

15. The welding method according to any one of claims 9 to 11, wherein, The ratio of the welding speed to the welding frequency of the continuous laser is equal to the ratio of the welding speed to the welding frequency of the pulsed laser.

16. The welding method according to any one of claims 9 to 11, wherein, The continuous laser emits the same single-point energy as the pulsed laser.

Images