Welding fixtures and welding systems

Abstract

This application relates to a welding fixture and a welding system. The welding fixture includes a base and a side plate. The side plate is disposed on one side of the base along a first direction, and the side plate and the base enclose a receiving space for accommodating an electrode assembly. The side plate includes two sets of opposing first side plates and two sets of opposing second side plates, which are sequentially connected. The first direction is parallel to the thickness direction of the base. Along the first direction, the side plate has at least one welding opening that communicates with the receiving space. The welding opening includes a first opening on the first side plate and a second opening on the second side plate, which communicate with each other. The welding opening exposes the tabs of the electrode assembly. This application can improve the yield of battery welding processes.

Description

Technical Field

[0001] This application relates to the field of battery welding technology, and in particular to welding fixtures and welding systems. Background Technology

[0002] Batteries are widely used in electronic devices such as mobile phones, laptops, electric vehicles, electric cars, electric airplanes, electric ships, electric toy cars, electric toy ships, electric toy airplanes, and power tools, etc.

[0003] In recent years, the new energy industry has developed rapidly, and lithium-ion batteries, due to their high energy density and high efficiency, have been widely used in electric vehicles, energy storage systems, and portable electronic devices. Battery assembly includes welding the tabs of the cells, using processes such as ultrasonic welding and laser welding. However, some batteries exhibit hipot defects after the welding process, reducing battery reliability. Utility Model Content

[0004] In view of the above problems, this application provides a welding fixture and welding system, which aims to improve the yield of battery welding process.

[0005] In a first aspect, this application proposes a welding fixture, including a base and a side plate; the side plate is disposed on one side of the base along a first direction, and the side plate and the base enclose a receiving space for accommodating an electrode assembly; the side plate includes two sets of opposing first side plates and two sets of opposing second side plates, the first side plates and the second side plates being connected in sequence; the first direction is parallel to the thickness direction of the base; wherein, along the first direction, the side plate is provided with at least one welding opening, the welding opening communicating with the receiving space; the welding opening includes a first opening disposed on the first side plate and a second opening disposed on the second side plate, the first opening communicating with the second opening; the welding opening is used to expose the tabs of the electrode assembly.

[0006] In this embodiment of the application, a receiving space is formed by setting a side plate and a base, and a welding opening communicating with the receiving space is opened on the side plate, so that the electrode assembly can be placed in the receiving space in a side-lying manner, with the electrode tab exposed from the welding opening. Using side welding, the metal slag generated during the welding process will fall towards the bottom of the fixture under the action of gravity, i.e., towards the base, and will not fall into the cell, thereby effectively avoiding hit defects and improving the yield of the welding process and the reliability of the battery. Setting welding openings at different positions on the side plate enhances the versatility and adaptability of the fixture. Setting a first and second opening that are connected creates a larger welding operation space at the corner of the side plate, improving the flexibility of the welding process.

[0007] In some embodiments, the first opening is provided on the side of the first side plate near the second side plate, and the surface area of ​​the first side plate is greater than the surface area of ​​the second side plate.

[0008] In these embodiments, the welding opening is located on the side of the first side plate with a larger surface area that is closer to the second side plate, so that the welding opening can be accurately aligned with the welding part of the electrode tab, which facilitates the welding operation.

[0009] In some embodiments, two sets of second side plates are arranged opposite each other along a second direction. Along the second direction, the width of the first side plate is A1, the depth of the first opening is a1, a1≤0.2*A1, and the second direction is perpendicular to the first direction.

[0010] In these embodiments, by controlling the depth of the first opening within a small proportion of the width of the first side plate, it is ensured that the welding opening does not excessively weaken the structural strength of the side plate, while ensuring effective exposure of the welding area.

[0011] In some embodiments, the two sets of first side plates are arranged opposite each other along a third direction; along the third direction, the width of the second side plate is A2, the depth of the second opening is a2, a2≤0.5*A2, and the third direction is perpendicular to the first direction.

[0012] In these embodiments, sufficient operating space is provided for lateral welding while ensuring the structural strength of the fixture.

[0013] In some embodiments, welding openings are provided on both sides of a second side plate.

[0014] In these embodiments, welding openings are provided on both sides of the same side plate, which allows a single fixture to weld the tabs on both sides of the electrode assembly simultaneously, thus improving welding efficiency.

[0015] In some embodiments, a plurality of welding openings are arranged sequentially at intervals along a first direction.

[0016] In these embodiments, by setting multiple welding openings spaced apart along the first direction, flexible matching can be made according to the actual number and distribution position of the electrode tabs, avoiding obstruction of non-welding areas and ensuring welding accuracy.

[0017] In some embodiments, the welding fixture further includes a top cover disposed at the end of the side plate away from the base.

[0018] In these embodiments, by providing a top cover, the electrode assembly can be limited and protected during the welding process, preventing displacement of the electrode assembly and improving welding stability.

[0019] In some embodiments, the number of welding openings is two, and the width of a single welding opening is 23 mm to 110 mm along the first direction; or, the number of welding openings is four, and the width of a single welding opening is 23 mm to 55 mm along the first direction.

[0020] In these embodiments, the number and width of the welding openings are configured in a coordinated manner as described above. On the one hand, the opening size corresponds precisely to the actual width and spacing of the tabs, ensuring that each tab or tab group can be fully exposed from the independent opening without interference, providing sufficient operating space for the welding tool. On the other hand, the opening width is controlled within a reasonable range, avoiding a decrease in the strength of the side plate structure or a weakening of the limiting ability of the electrode assembly due to excessively wide openings.

[0021] In some embodiments, the number of welding openings is two, and the opening area of ​​a single welding opening is 280 mm². 2 Up to 480mm 2 Alternatively, the number of welding openings is four, and the opening area of ​​each welding opening is 140mm. 2 Up to 240mm 2 .

[0022] In these embodiments, while meeting the welding requirements of different tab arrangement schemes, the area of ​​each opening is sufficient to accommodate welding tools to enter and perform stable welding on the tabs, without excessively weakening the structural strength of the side plate or causing the electrode assembly to loosen its position within the accommodating space due to excessive area.

[0023] Secondly, this application proposes a welding system including a welding fixture according to any embodiment of the first aspect described above; it also includes a laser welding head for emitting a laser beam toward a welding opening to weld the tabs of an electrode assembly.

[0024] 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, specific embodiments of this application are given below. Attached Figure Description

[0025] The features, advantages, and technical effects of exemplary embodiments of this application will now be described with reference to the accompanying drawings.

[0026] Figure 1 This is a schematic diagram of the exploded structure of a single battery cell provided in an embodiment of this application;

[0027] Figure 2 This is one of the three-dimensional structural schematic diagrams of a welding fixture provided in an embodiment of this application;

[0028] Figure 3 This is a cross-sectional structural schematic diagram of a welding fixture and electrode assembly provided in an embodiment of this application;

[0029] Figure 4This is a three-dimensional structural diagram of a first side plate in a welding fixture provided in an embodiment of this application;

[0030] Figure 5 This is a three-dimensional structural diagram of a welding fixture provided in an embodiment of this application, with a first side plate concealed.

[0031] Figure 6 This is a second three-dimensional structural schematic diagram of a welding fixture provided in one embodiment of this application.

[0032] The accompanying drawings may not be drawn to scale.

[0033] Explanation of reference numerals in the attached figures:

[0034] 10. Battery cell; 11. Housing; 12. Electrode assembly; 13. End cap assembly;

[0035] 21. Base; 22. Top cover;

[0036] 3. Side panel; 31. First side panel; 32. Second side panel;

[0037] 4. Accommodation space; 40. Welding opening; 41. First opening; 42. Second opening;

[0038] Z, first direction; X, second direction; Y, third direction. Detailed Implementation

[0039] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0040] Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used in the description of this application 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 description, claims, and accompanying drawings of this application are intended to cover non-exclusive inclusion. The terms "first," "second," etc., in the description, claims, or accompanying drawings of this application are used to distinguish different objects, not to describe a specific order or hierarchy.

[0041] In this application, the reference to "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 in the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment that is mutually exclusive with other embodiments.

[0042] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "attachment" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0043] 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 three cases: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, in this application, the character " / " generally indicates that the preceding and following related objects have an "or" relationship.

[0044] In the embodiments of this application, the same reference numerals denote the same components, and for the sake of brevity, detailed descriptions of the same components are omitted in different embodiments. It should be understood that the thickness, length, width, and other dimensions of various components in the embodiments of this application shown in the accompanying drawings, as well as the overall thickness, length, width, and other dimensions of the integrated device, are merely illustrative and should not constitute any limitation on this application.

[0045] In this application, "multiple" means two or more (including two).

[0046] In recent years, the new energy industry has developed rapidly. Lithium-ion batteries, due to their high energy density and high efficiency, have been widely used in electric vehicles, energy storage systems, and portable electronic devices. Designing and using large-capacity (500Ah and above) energy storage cells can bring greater volumetric energy density, thereby improving the overall efficiency of cells and cabinets and bringing considerable economic benefits.

[0047] The welding of battery cell tabs includes ultrasonic welding and laser welding processes. However, some batteries exhibit hipot defects after the welding process, reducing battery reliability. Hipot testing, also known as high-potential testing or withstand voltage testing, is a test method that verifies electrical isolation characteristics by applying pressure higher than the normal operating voltage to the insulating parts of a device or system.

[0048] To address the aforementioned issues, this application provides a welding fixture comprising a base and side plates. The welding fixture provides stable mechanical constraint on the electrode assembly during welding. By enclosing the base with the side plates, a receiving space is formed, and welding openings communicating with this space are provided on the side plates. This allows the electrode assembly to be placed sideways within the receiving space, with the tabs protruding from the welding openings. Using side welding, the metal slag generated during the welding process falls towards the bottom of the fixture under gravity, i.e., towards the base, instead of falling into the battery cell, effectively avoiding hit-pot defects and improving welding yield and battery reliability. The welding openings at different positions on the side plates enhance the fixture's versatility and adaptability. The interconnected first and second openings create a larger welding operation space at the corners of the side plates, improving the flexibility of the welding process.

[0049] Figure 1 An exploded structural diagram of a battery cell according to an embodiment of this application is shown.

[0050] A battery cell 10 refers to the smallest unit that makes up a battery. A battery cell 10 includes a housing 11, an electrode assembly 12, and an end cap assembly 13.

[0051] Electrode assembly 12 is the component in the battery cell 10 where electrochemical reactions occur. The housing 11 may contain one or more electrode assemblies 12. The electrode assembly 12 is mainly formed by winding or stacking electrode sheets, which are divided into positive and negative electrode sheets, and a separator is usually provided between the positive and negative electrode sheets. The portions of the positive and negative electrode sheets containing active material constitute the electrode body, while the portions of the positive and negative electrode sheets without active material each constitute a tab. The positive and negative tabs can be located together at one end of the electrode body or separately at both ends of the electrode body. During the charging and discharging process of the battery cell 10, the positive and negative active materials react with the electrolyte, and the tabs connect to the electrode terminals to form a current loop.

[0052] As an example, the battery cell 10 can be a cylindrical battery cell, a prismatic battery cell, a pouch battery cell, or a battery cell of other shapes. Prismatic battery cells include prismatic battery cells, blade-shaped battery cells, and multi-prismatic batteries, such as hexagonal prismatic batteries. This application does not have any particular limitations.

[0053] The housing 11 and the end cap assembly 13 can be independent components. One or more openings can be provided on the housing 11, and one or more end cap assemblies 13 can close the openings to form the internal environment of the battery cell 10. Optionally, the end cap assembly 13 and the housing 11 can be integrated. Optionally, the end cap assembly 13 and the housing 11 can form a common connection surface before other components are inserted into the housing, and the end cap assembly 13 closes the housing 11 when it is necessary to encapsulate the interior of the housing 11.

[0054] In some embodiments, the end cap assembly 13 is provided with at least one electrode terminal, which is electrically connected to the electrode tab. The electrode terminal can be directly connected to the electrode tab or indirectly connected to the electrode tab through a current collector. In addition, the electrode terminal can be provided not only on the end cap assembly 13, but also on the housing 11.

[0055] In some embodiments, the battery cell 10 also includes an electrolyte, which acts as a conductor of ions between the positive and negative electrodes.

[0056] Reference Figure 2 and Figure 3 In a first aspect, this application proposes a welding fixture, which includes a base 21 and a side plate 3. The side plate 3 is disposed on one side of the base 21 along a first direction Z, and the side plate 3 and the base 21 enclose a receiving space 4 for accommodating an electrode assembly 12. The side plate 3 includes two sets of opposing first side plates 31 and two sets of opposing second side plates 32, which are connected in sequence. The first direction Z is parallel to the thickness direction of the base 21. Along the first direction Z, the side plate 3 is provided with at least one welding opening 40, which communicates with the receiving space 4. The welding opening 40 includes a first opening 41 on the first side plate 31 and a second opening 42 on the second side plate 32, which communicate with each other. The welding opening 40 is used to expose the tabs of the electrode assembly 12.

[0057] The welding fixture is a tooling used to fix the electrode assembly 12 in the electrode tab welding process of the battery cell. The base 21 serves as a bearing base to support the entire fixture structure, and its bearing surface can be larger than the cross-section enclosed by the side plate 3. The accommodating space 4 formed by the base 21 and the side plate 3 can limit the positional displacement of the electrode assembly 12 during the welding process. For example, the base 21 can be a flat plate.

[0058] The receiving space 4 is used to accommodate the electrode assembly 12, which can be a stacked or wound lithium-ion battery cell. The welding opening 40 on the side plate 3 serves as a window structure penetrating the side plate 3 and communicating with the receiving space 4, directionally exposing the tab area of ​​the electrode assembly 12 during welding, providing a precise operating channel for welding tools (such as ultrasonic welding heads or laser welding heads). Using this welding fixture, the electrode assembly 12 can be placed into the receiving space 4 in a side-lying manner.

[0059] The side-lying method means that different tabs on one side of the electrode assembly 12 are arranged sequentially along the first direction Z, and the welding opening 40 arranged along the first direction Z can precisely expose the corresponding tabs.

[0060] For example, a pre-welded flange can be paired with an ultrasonically welded tab at the weld opening 40. A laser welding head emits a laser beam from the side, passing through the weld opening 40 to weld the tabs.

[0061] The first side panel 31 and the second side panel 32 are connected in sequence, for example, to form a rectangular frame.

[0062] After the electrode assembly 12 is placed in the receiving space 4 in a side-lying manner, directional exposure windows can be formed at the corresponding height of the corresponding side plate 3 according to the distribution position of the tabs. With this four-sided enclosure structure that can flexibly open welding openings 40, the welding tools can perform welding operations from the side (i.e., side welding) because the welding openings 40 are located on the side plate 3. The resulting metal slag will naturally fall towards the base 21 under the action of gravity, and will not fall into the interior of the electrode assembly 12, thereby reducing the risk of insulation failure caused by slag residue, effectively improving hit-pot defects, and improving the yield of the welding process and the electrical reliability of the battery product.

[0063] The second opening 42 refers to the welding opening 40 provided on the second side plate 32, which is connected to the first opening 41 provided on the first side plate 31 at the corner of the side plate 3 structure, forming a continuous opening structure spanning adjacent side plates 3. This "L"-shaped or continuous opening design provides more operating space for welding.

[0064] The first opening 41 and the second opening 42 are configured to be interconnected, so that the welding opening 40 is no longer limited to a single side plate 3, but extends to the junction area of ​​the first side plate 31 and the second side plate 32. This allows the electrode tabs located at the corners or arranged along different sides of the electrode assembly 12 to be exposed at the same time, providing a more flexible operating space and a larger incident angle for the welding tool. This is especially suitable for process scenarios where the electrode tabs are concentrated or require multi-directional welding.

[0065] In this embodiment, the welding fixture includes a base 21 and a side plate 3. The welding fixture provides stable mechanical constraint on the electrode assembly 12 during welding. The side plate 3 and base 21 enclose a receiving space 4, and a welding opening 40 communicating with the receiving space 4 is provided on the side plate 3. This allows the electrode assembly 12 to be placed sideways within the receiving space 4, with the electrode tabs exposed through the welding opening 40. By employing side welding, the metal slag generated during welding will fall towards the bottom of the fixture under gravity, i.e., towards the base 21, instead of falling into the battery cell, effectively avoiding hit-pot defects and improving the welding yield and battery reliability. The welding openings 40 at different positions on the side plate 3 allow for flexible adaptation to various electrode tab distribution schemes, such as single-cathode anode tabs or dual-cathode anode tabs, enhancing the fixture's versatility and adaptability. The interconnected first opening 41 and second opening 42 create a larger welding operation space at the corner of the side plate 3, improving the flexibility of the welding process.

[0066] The shape of the tabs can extend away from the main body of the electrode assembly 12. This structural design supports the side welding process of "first pairing into the fixture, then laser welding," and can effectively reduce the space required for folding the tabs, thereby leaving more width for the electrode sheets and improving the overall capacity and volumetric energy density of the cell. For example, the laser welding imprint is on the ultrasonic welding imprint, and the laser welding imprint area accounts for 35%-80% of the ultrasonic welding imprint area.

[0067] Reference Figure 2 In some embodiments, the first opening 41 is disposed on the side of the first side plate 31 near the second side plate 32, and the surface area of ​​the first side plate 31 is larger than the surface area of ​​the second side plate 32.

[0068] The first side plate 31 is used for the side with a larger area corresponding to the electrode assembly 12.

[0069] The specific location of the first opening 41 is defined as the edge region of the first side plate 31 adjacent to the second side plate 32. Since the surface area of ​​the first side plate 31 is larger than that of the second side plate 32, the first opening 41 can precisely correspond to the positions of the tabs arranged along the first direction Z in the electrode assembly 12 with a larger opening size or a more flexible layout. On the one hand, the larger load-bearing and fixing area of ​​the first side plate 31 can enhance the lateral support stability of the electrode assembly 12; on the other hand, it allows the welding opening 40 to be closer to the corner region of the receiving space 4, thereby enabling precise alignment with the extension direction and distribution position of the tabs after the electrode assembly 12 is placed in a side-lying position.

[0070] In these embodiments, the welding opening 40 is located on the side of the first side plate 31 with a larger surface area that is closer to the second side plate 32, so that the welding opening 40 can be accurately aligned with the welding part of the electrode tab, which facilitates the welding operation.

[0071] Reference Figure 4 In some embodiments, two sets of second side plates 32 are arranged opposite each other along the second direction X. Along the second direction X, the width of the first side plate 31 is A1, the depth of the first opening 41 is a1, a1≤0.2*A1, and the second direction X is perpendicular to the first direction Z.

[0072] The depth of the first opening 41 refers to the dimension by which the first opening 41 extends from the edge of the side plate 3 into the interior of the side plate 3. The depth of the first opening 41 is limited to no more than one-fifth of the width of the first side plate 31. Under the premise of ensuring that the welding laser can smoothly pass through the welding opening 40 from the side and perform welding operations on the electrode tab, the main structure of the first side plate 31 is preserved to the maximum extent, thereby maintaining the continuous support and reliable positioning of the electrode assembly 12 in the second direction X of the side plate 3. At the same time, the shallower opening depth makes the area of ​​the electrode tab exposed from the side plate 3 closer to the outer edge of the receiving space 4. Under the action of gravity, the metal slag generated during welding can fall more thoroughly towards the base 21, further reducing the risk of slag splashing into the cell.

[0073] In these embodiments, by controlling the depth of the first opening 41 within a small proportion of the width of the first side plate 31, it is ensured that the welding opening 40 does not excessively weaken the structural strength of the side plate 3, while ensuring effective exposure of the welding area.

[0074] Reference Figure 5 In some embodiments, the two sets of first side plates 31 are arranged opposite each other along a third direction Y; along the third direction Y, the width of the second side plate 32 is A2, the depth of the second opening 42 is a2, a2≤0.5*A2, and the third direction Y is perpendicular to the first direction Z. The first direction Z, the second direction X, and the third direction Y can be perpendicular to each other.

[0075] The depth of the second opening 42 refers to the dimension by which the second opening 42 extends from the edge of its corresponding side plate 3 into the interior of the side plate 3. The depth of the second opening 42 is limited to no more than half the width of the second side plate 32. By controlling the depth of the second opening 42 within this proportional range, while achieving multi-directional welding accessibility through the communication structure between the second opening 42 and the first opening 41, the main structure of the second side plate 32 can retain sufficient width to maintain its structural strength and support stability, thus avoiding deformation of the side plate 3 under welding stress or failure of the limiting function of the electrode assembly 12 due to excessively deep openings.

[0076] In these embodiments, by defining the ratio between the depth a2 of the second opening 42 and the width A2 of the second side plate 32, sufficient operating space is provided for lateral welding while ensuring the structural strength of the fixture.

[0077] At the same time, it also facilitates the provision of welding openings 40 on both sides of the first side plate 31. In these examples, a2 < 0.5 * A2.

[0078] In some embodiments, welding openings 40 (not shown, but can be understood as) are provided on both sides of a second side plate 32. Figure 4 The first side plate 31 shown has two sets.

[0079] On one of the second side plates 32 constituting the welding fixture, welding openings 40 are provided on both opposite sides along the third direction Y (or only on the two sets of first side plates 31 on both sides), so that the second side plate 32 can form window structures communicating with the receiving space 4 at the corners adjacent to the first side plates 31 on both sides.

[0080] When welding openings 40 are opened on both sides of the second side plate 32, the sum of the depths of the openings on both sides does not exceed the overall width of the second side plate 32. This ensures that the central area of ​​the second side plate 32 retains sufficient solid structure to maintain reliable support and limit of the electrode assembly 12 while achieving double-sided welding accessibility.

[0081] By providing double-sided welding openings 40 on the same second side plate 32, the welding requirements for tabs distributed on opposite sides of the electrode assembly 12 can be accommodated, reducing the need for fixture adjustment or electrode assembly 12 flipping. For example, the fixture has openings on both opposite sides, allowing for simultaneous welding of tabs on two JRs (Junior cells) or four JRs in a single welding operation. Subsequent installation into the housing is then possible without requiring two separate welding operations, thus improving production efficiency.

[0082] In these embodiments, welding openings 40 are provided on both sides of the same side plate 3, which can enable a single fixture to weld the tabs on both sides of the electrode assembly 12 simultaneously, thereby improving welding efficiency.

[0083] In some embodiments, a plurality of welding openings 40 are arranged at intervals along a first direction Z.

[0084] Multiple (two or more) welding openings 40 are arranged sequentially along the first direction Z (i.e. the direction in which the side plate 3 is erected, consistent with the arrangement direction of the electrode tabs after the electrode assembly 12 is laid on its side) in a way that they are separate from each other and do not communicate with each other, forming a set of independent window structures distributed along the height direction.

[0085] Multiple welding openings 40 are arranged at intervals along the first direction Z. When the electrode assembly 12 is placed into the receiving space 4 in a side-lying manner, multiple tabs (such as positive tabs and negative tabs, or each tab group in a multi-tab structure) arranged sequentially along the first direction Z on the electrode assembly 12 can form a one-to-one exposure relationship with the welding openings 40 at the corresponding heights. Each welding opening 40 independently corresponds to one tab or a group of tabs for welding operations, avoiding the problems of mutual interference, cross-contamination of welding spatter, or limited operating space that may occur when multiple tabs share one opening.

[0086] In these embodiments, by setting multiple welding openings 40 spaced apart along the first direction Z, flexible matching can be made according to the actual number and distribution position of the electrode tabs, avoiding obstruction of non-welding areas and ensuring welding accuracy.

[0087] Reference Figure 2 or Figure 6 In some embodiments, the welding fixture further includes a top cover 22, which is disposed at the end of the side plate 3 away from the base 21.

[0088] The top cover 22 refers to the cover structure located at the end of the side plate 3 away from the base 21. It is arranged opposite to the base 21 and together with the side plate 3, it encloses the vertically closed or semi-closed housing space 4 of the electrode assembly 12.

[0089] A top cover 22 is added to the top of the welding fixture. On the one hand, the base 21, the side plate 3 and the top cover 22 form a complete frame-type limiting structure, which forms an all-round mechanical constraint on the electrode assembly 12 during the welding process. This effectively prevents the electrode assembly 12 from moving upward or tilting when subjected to lateral welding force, and further improves the alignment accuracy and welding stability of the electrode tab and the welding opening 40. On the other hand, the top cover 22 and the base 21 work together to form a relatively closed working environment in the accommodating space 4. When the side welding process is used, the metal slag produced by welding falls towards the base 21 under the action of gravity. The setting of the top cover 22 restricts the possible upward path of the slag from above, further preventing the slag from splashing to the outside or falling back into the cell area.

[0090] In these embodiments, by providing the top cover 22, the electrode assembly 12 can be limited and protected during the welding process, preventing displacement of the electrode assembly 12 during welding and improving welding stability.

[0091] Reference Figure 2 or Figure 6 In some embodiments, the number of welding openings 40 is two, and the width of a single welding opening 40 along the first direction Z is 23mm to 110mm; or, the number of welding openings 40 is four, and the width of a single welding opening 40 along the first direction Z is 23mm to 55mm.

[0092] Depending on the different requirements of the electrode assembly 12 tab arrangement, when welding openings 40 are made on the side plate 3, two or four openings can be selected, and the size of each opening along the first direction Z (i.e. the arrangement direction of the tabs after the electrode assembly 12 is laid on its side) is specifically limited: when two welding openings 40 are set, the width of each opening is in the range of 23mm to 110mm to adapt to wider tab groups or bipolar structures; when four welding openings 40 are set, the width of each opening is in the range of 23mm to 55mm to match the relatively narrow distribution spacing of each tab in a multi-tab structure.

[0093] In these embodiments, the number and width of the welding openings 40 are configured in a coordinated manner as described above. On the one hand, the opening size corresponds precisely to the actual width and spacing of the tabs, ensuring that each tab or tab group can be fully exposed from the independent opening without interference, providing sufficient operating space for the welding tool. On the other hand, the opening width is controlled within a reasonable range, avoiding a decrease in the structural strength of the side plate 3 or a weakening of the limiting ability of the electrode assembly 12 due to excessively wide openings.

[0094] Reference Figure 2 or Figure 6 In some embodiments, the number of welding openings 40 is two, and the opening area of ​​a single welding opening 40 is 280 mm². 2 Up to 480mm 2 Alternatively, the number of welding openings 40 is four, and the opening area of ​​each welding opening 40 is 140mm². 2 Up to 240mm 2 .

[0095] The opening area refers to the area of ​​the opening region of a single welded opening 40 on the plane where the side plate 3 is located.

[0096] In these embodiments, while meeting the welding requirements of different tab arrangement schemes, the area of ​​each opening is sufficient to accommodate welding tools to enter and perform stable welding on the tabs, without excessively weakening the structural strength of the side plate 3 or causing the electrode assembly 12 to loosen its position within the accommodating space 4 due to excessive area.

[0097] This fixture allows for adjustments to the number of openings on its side plate based on the number of tabs, optimizing the laser soldering area by changing the opening size. This results in larger energy storage cells with higher energy conversion efficiency and longer cycle life. By limiting the aforementioned size range, the laser soldering area can be precisely controlled, ensuring that the ratio of the laser soldering area to the ultrasonic soldering area is within the optimal process window of 35% to 80%. This ratio significantly optimizes the cell's current handling capability. Experimental data shows that by optimizing the soldering area (e.g., increasing it by 50%), the cell's energy conversion efficiency (RTE) can be improved by 0.3%; with a full-tab design, the RTE can be further improved by 0.5%.

[0098] For example, the battery cells placed in the welding fixture can be 2 JR cells or 4 JR cells. The width of a single JR cell ranges from 140mm to 490mm, the height ranges from 120mm to 280mm, and the thickness ranges from 10mm to 40mm. The actual size of the front and rear first side plates 31 is set as follows: height ranges from 150mm to 500mm (corresponding to cell width), preferably 170mm to 400mm; width ranges from 150mm to 300mm (corresponding to cell height), preferably 200mm to 250mm; thickness ranges from 40mm to 150mm (corresponding to cell thickness), preferably 70mm to 80mm. The number of welding openings 40 can be 2 or 4. The width of the welding openings 40 on the first side plate 31 of the fixture can be the width of a single opening area (23mm-110mm) * 2 or (23mm-55mm) * 4.

[0099] Secondly, embodiments of this application provide a welding system including a welding fixture according to any of the embodiments of the first aspect above, and a laser welding head for emitting a laser beam toward the welding opening 40 to weld the tabs of the electrode assembly 12.

[0100] Please see Figures 2 to 6According to some embodiments of this application, this application provides a welding fixture, which includes a base 21 and a side plate 3. The side plate 3 is disposed on one side of the base 21 along a first direction Z, and the side plate 3 and the base 21 enclose a receiving space 4 for accommodating an electrode assembly 12. The side plate 3 includes two sets of opposing first side plates 31 and two sets of opposing second side plates 32, which are sequentially connected. The first direction Z is parallel to the thickness direction of the base 21. Along the first direction Z, the side plate 3 has at least one welding opening 40, which communicates with the receiving space 4. The welding opening 40 includes a first opening 41 on the first side plate 31 and a second opening 42 on the second side plate 32, which communicate with each other. The welding opening 40 is used to expose the tabs of the electrode assembly 12. Multiple welding openings 40 are sequentially spaced along the first direction Z. The welding fixture also includes a top cover 22, which is disposed at the end of the side plate 3 away from the base 21.

[0101] Although this application has been described with reference to preferred embodiments, various modifications can be made thereto and components can be replaced with equivalents without departing from the scope of this application. In particular, the technical features mentioned in the various embodiments can be combined in any manner, provided there is no structural conflict. 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 welding fixture, characterized in that, include: Base; A side plate is disposed on one side of the base along a first direction. The side plate and the base enclose a receiving space for accommodating an electrode assembly. The side plate includes two sets of opposing first side plates and two sets of opposing second side plates. The first side plates and the second side plates are connected in sequence. The first direction is parallel to the thickness direction of the base. Along the first direction, the side plate is provided with at least one welding opening, which communicates with the receiving space. The welding opening includes a first opening on the first side plate and a second opening on the second side plate. The first opening communicates with the second opening, and the welding opening is used to expose the tabs of the electrode assembly.

2. The welding fixture according to claim 1, characterized in that, The first opening is located on the side of the first side plate near the second side plate, and the surface area of ​​the first side plate is larger than the surface area of ​​the second side plate.

3. The welding fixture according to claim 2, characterized in that, The two sets of second side plates are arranged opposite each other along the second direction. Along the second direction, the width of the first side plate is A1, the depth of the first opening is a1, a1≤0.2*A1, and the second direction is perpendicular to the first direction.

4. The welding fixture according to claim 1, characterized in that, The two sets of first side plates are arranged opposite each other along a third direction. Along the third direction, the width of the second side plate is A2, the depth of the second opening is a2, a2≤0.5*A2, and the third direction is perpendicular to the first direction.

5. The welding fixture according to any one of claims 1 to 4, characterized in that, The welding openings are provided on both sides of the second side plate.

6. The welding fixture according to any one of claims 1 to 4, characterized in that, The plurality of welding openings are arranged sequentially at intervals along the first direction.

7. The welding fixture according to any one of claims 1 to 4, characterized in that, The welding fixture also includes a top cover, which is disposed at the end of the side plate away from the base.

8. The welding fixture according to any one of claims 1 to 4, characterized in that, The number of welding openings is two, and the width of a single welding opening is 23mm to 110mm along the first direction; Alternatively, the number of welding openings is four, and the width of a single welding opening is 23 mm to 55 mm along the first direction.

9. The welding fixture according to any one of claims 1 to 4, characterized in that, The number of the welding openings is two, the opening area of a single welding opening is 280mm 2 to 480mm 2 ; Alternatively, the number of welding openings is four, and the opening area of ​​each welding opening is 140 mm². 2 Up to 240mm 2 .

10. A welding system, characterized in that, Including the welding fixture as described in any one of claims 1 to 9; further comprising: A laser welding head is used to emit a laser beam into the welding opening to weld the tabs of the electrode assembly.

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