Single battery

Abstract

The utility model provides a single battery. The single battery comprises a shell; the cover plate assembly and the shell jointly define a containing cavity, the cover plate assembly comprises a cover plate body and an electrode terminal penetrating through the cover plate body, the electrode terminal comprises a penetrating part and a connecting plate which are connected, the penetrating part penetrates through the pole through hole of the cover plate body, and the side, facing the electrode assembly, of the connecting plate is provided with a positioning part protruding towards the direction of the electrode assembly; the electrode assembly is accommodated in the accommodating cavity, and a tab of the electrode assembly is arranged on the positioning part in a covering manner; the wrapping piece is matched with the positioning part in shape and covers one side, far away from the positioning part, of the tab, the tab is pressed between the wrapping piece and the positioning part, and the wrapping piece, the tab and the positioning part are connected in a welded mode in the height direction of the cover plate assembly. According to the single battery disclosed by the utility model, the pre-welding process of the tabs can be canceled, and laser welding of the tabs and the connecting plates of the electrode terminals can be directly carried out, so that the process cost is saved, and the foreign matter control problem of an ultrasonic process is avoided.

Description

Technical Field

[0001] The utility model relates to a single battery. Background Art

[0002] With the continuous advancement of lithium-ion battery technology, the demand for battery energy density is getting higher and higher. Among them, square laminated lithium-ion batteries can achieve higher energy density due to their higher assembly ratio. Currently, square laminated lithium-ion power batteries with single-side electrode terminals (electrode columns) generally use the method of pre-welding the tabs and then laser welding them to the electrode terminals of the cover assembly to achieve the connection between the positive and negative terminals of the battery and the laminated battery cell. There are two main technical solutions for welding the tabs to the electrode terminals:

[0003] Technical Solution 1: By ultrasonically pre-welding the battery tabs to form a constraint, the ultrasonic welding position of the battery tabs is directly laser-welded to the guide bottom plate at the electrode terminal position, thereby achieving a stable connection between the battery tabs and the guide structure;

[0004] Technical solution 2: First, ultrasonically weld the battery tabs and the adapter, and then laser weld the adapter and the electrode terminal. The idea of ​​the solution is to connect the battery tabs and the electrode terminals through the adapter structure.

[0005] In both of the above technical solutions, ultrasonic pre-welding is required to constrain the battery tabs, and then laser welding is used to connect the tabs to the electrode terminals. However, there is currently no effective quality monitoring method for existing ultrasonic pre-welded products. When quality problems occur in the product, it is difficult to identify them in a timely manner, and remedial measures are also very scarce. Secondly, the ultrasonic welding process itself is accompanied by a large amount of metal foreign matter splashing, which can easily cause serious quality problems such as excessive foreign matter in the battery cell, and a large amount of cost must be invested in foreign matter control during the welding process. Utility Model Content

[0006] The technical problem to be solved by the present invention is to overcome the defect in the prior art that an ultrasonic pre-welding method is required to constrain the battery tabs and then a laser welding method is used to connect the tabs to the electrode terminals. It is difficult to monitor the quality of the ultrasonic pre-welded products, and the ultrasonic welding process itself is accompanied by a large amount of metal foreign matter splashing, which can easily cause the battery cell to have excessive foreign matter and affect the quality. A single battery is provided.

[0007] The utility model solves the above technical problems through the following technical solutions:

[0008] A single cell battery, characterized in that it comprises:

[0009] case;

[0010] a cover plate assembly, which is disposed on the housing and defines a receiving cavity together with the housing; the cover plate assembly includes a cover plate body and an electrode terminal; the cover plate body has a through-hole for a pole; the electrode terminal includes a through-portion and a connecting plate connected thereto; the through-portion at least partially penetrates the through-hole for the pole; the connecting plate is located on a side of the cover plate body facing the electrode assembly; and a positioning portion protruding toward the electrode assembly is provided on the side of the connecting plate facing the electrode assembly;

[0011] an electrode assembly accommodated in the accommodation cavity, with the tab of the electrode assembly covering the positioning portion;

[0012] The covering sheet matches the shape of the positioning portion, and the covering sheet is covered on the side of the pole ear away from the positioning portion, and the pole ear is pressed between the covering sheet and the positioning portion. Along the height direction of the cover plate assembly, the covering sheet, the pole ear, and the positioning portion are welded together.

[0013] In this technical solution, by pressing the tab between the cover sheet and the positioning portion, and welding the cover sheet, tab, and positioning portion together along the height of the cover plate assembly, the pre-welding process of the tab can be eliminated, and the tab and the electrode terminal connection plate can be directly laser welded. This saves process costs while avoiding the foreign matter control issues of the ultrasonic process, indirectly improving product yield and ensuring that the battery's current capacity is not affected. Furthermore, pressing the tab between the matching cover sheet and positioning portion not only meets the requirements of pre-welding tab compression, but also ensures that the tab will not be damaged by the compression action.

[0014] Preferably, along the height direction of the cover plate assembly, the orthographic projection of the weld mark formed by welding the covering sheet, the tab and the positioning portion is located within the outer periphery of the positioning portion; and / or,

[0015] Along the height direction of the cover plate assembly, the orthographic projection of the covering sheet is located within the outer periphery of the connecting plate.

[0016] In this technical solution, by setting the orthographic projection of the weld mark to be located within the outer periphery of the positioning portion, a better welding connection between the covering sheet, the tab and the positioning portion can be ensured; by setting the orthographic projection of the covering sheet to be located within the outer periphery of the connecting plate, interference of the covering sheet with surrounding components can be avoided.

[0017] Preferably, the extending direction of the weld mark is the same as the extending direction of the positioning portion, and is the same as the length direction of the connecting plate.

[0018] In this technical solution, by arranging the extending direction of the welding mark to be in the same direction as the extending direction of the positioning portion and in the same direction as the length direction of the connecting plate, a larger pressure-bearing surface can be provided, thereby making the welding more firm.

[0019] Preferably, the length of the weld mark is greater than or equal to 30% of the length of the positioning portion and less than or equal to 60% of the length of the positioning portion; and / or,

[0020] The width of the weld mark is greater than or equal to 50% of the width of the positioning portion and is smaller than the width of the positioning portion.

[0021] In this technical solution, by setting the value range of the ratio of the size of the weld mark to the size of the positioning portion, it is avoided that the size of the weld mark is too small, which affects the strength of the welding; and if the size of the weld mark is too large, the heat during welding will cause damage to the surrounding components.

[0022] Preferably, the welding mark and the positioning portion are both in the shape of long strips.

[0023] In the present technical solution, by setting the shape of the weld mark positioning parts to be long strips, a larger pressure-bearing surface can be provided, thereby making the welding more firm.

[0024] Preferably, along the width direction of the connecting plate, the surface of the positioning portion includes a first side surface, a top surface and a second side surface connected in sequence, the first side surface extends obliquely toward the center position of the top surface from an end away from the top surface to an end close to the top surface, the plane where the top surface is located is parallel to the plane where the connecting plate is located, the second side surface extends obliquely toward the center position of the top surface from an end away from the top surface to an end close to the top surface, and the first side surface and the second side surface are symmetrically arranged about the center line of the longitudinal direction of the top surface.

[0025] In this technical solution, a specific setting method of the positioning part is provided through the above setting.

[0026] Preferably, the first side surface and the plane where the connecting plate is located form a first angle, and the first angle is 30 degrees to 60 degrees; and / or,

[0027] The second side surface forms a second angle with the plane where the connecting plate is located, and the second angle is 30 degrees to 60 degrees.

[0028] In this technical solution, by setting a value range for the first angle, it is possible to avoid the first side surface from being tilted too much, which would easily damage the tab pressed between the cover sheet and the positioning portion, while the tilt angle being too small would not achieve the clamping effect. By setting a value range for the second angle, it is possible to avoid the first side surface from being tilted too much, which would easily damage the tab pressed between the cover sheet and the positioning portion, while the tilt angle being too small would not achieve the clamping effect.

[0029] Preferably, along the width direction of the connecting plate, the covering sheet includes a first part, a second part, a third part, a fourth part, and a fifth part connected in sequence, the first part and the fifth part are both arranged corresponding to the connecting plate, the second part is arranged corresponding to the first side surface of the positioning part, the third part is arranged corresponding to the top surface of the positioning part, and the fourth part is arranged corresponding to the second side surface of the positioning part.

[0030] In this technical solution, by providing a specific structure of the covering sheet, the tab can be better pressed between the covering sheet and the positioning portion, and the tab can be better protected.

[0031] Preferably, along the height direction of the cover plate assembly, the height of the positioning portion is greater than or equal to 20% and less than or equal to 50% of the thickness of the connecting plate; and / or,

[0032] Along the height direction of the cover plate assembly, the thickness of the covering sheet is less than or equal to 0.2 mm.

[0033] In this technical solution, by setting a range of values ​​for the positioning portion's height, we can prevent the positioning portion from being too high, thus occupying too much internal battery space, and the positioning portion from being too low, thus failing to provide a tight fit. By setting the cover sheet thickness to be less than or equal to 0.2mm, we can prevent the cover sheet from being too thick, resulting in a loose tab press and indirectly causing process defects in the subsequent laser welding step.

[0034] Preferably, the covering sheet, the tab and the positioning portion are connected by laser welding, a laser welding nozzle acts on the covering sheet, and the shape of the nozzle matches the shape of the covering sheet.

[0035] In this technical solution, by setting the shape of the laser welding nozzle to match the shape of the covering sheet, it is possible to press the tab and the covering sheet tightly while ensuring that the tab is not fractured.

[0036] Preferably, the pressure exerted by the pressing nozzle on the covering sheet is less than or equal to 800 kg.

[0037] In this technical solution, since the top cover assembly is assembled from multiple components, by setting the range of values ​​of the pressure applied by the pressure nozzle on the covering sheet, it is possible to avoid excessive pressure applied by the pressure nozzle, causing failure of the connection between multiple components, thereby affecting the overall sealing of the finalization assembly.

[0038] The positive progress effect of this utility model is:

[0039] The present invention presses the tab between the cover sheet and the positioning portion, and welds the cover sheet, tab, and positioning portion along the height direction of the cover plate assembly. This eliminates the pre-welding process and allows direct laser welding of the tab to the connecting plate of the electrode terminal. This saves process costs while avoiding the foreign matter control issues of the ultrasonic process, indirectly improving product yield and ensuring that the battery's overcurrent capacity is not affected. Furthermore, pressing the tab between the matching cover sheet and positioning portion not only meets the requirements for pre-welding tab compression, but also ensures that the tab will not be damaged by the compression action. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 This is a partial structural diagram of a single cell according to a preferred embodiment of the present invention.

[0041] Figure 2 This is a partial structural diagram of a single cell according to a preferred embodiment of the present invention from another angle.

[0042] Figure 3 for Figure 2 A partial enlarged view of part A.

[0043] Figure 4 This is a partial structural diagram of a cover assembly according to a preferred embodiment of the present invention.

[0044] Figure 5 This is a partial structural diagram from another angle of a cover assembly of a preferred embodiment of the present invention.

[0045] Figure 6 for Figure 5 A partial enlarged view of part B.

[0046] Figure 7 The figure is a schematic top view of the covering sheet according to a preferred embodiment of the present invention.

[0047] Figure 8 The figure is a schematic cross-sectional structural diagram of a covering sheet according to a preferred embodiment of the present invention.

[0048] Figure 9 This is a structural schematic diagram of an electrode assembly according to a preferred embodiment of the present invention (1).

[0049] Figure 10 This is a structural schematic diagram of an electrode assembly according to a preferred embodiment of the present invention (II).

[0050] Description of Reference Numerals

[0051] Cover assembly 1

[0052] Cover body 10

[0053] Electrode terminal 20

[0054] Through portion 21

[0055] Connecting plate 22

[0056] Positioning portion 23

[0057] First side 231

[0058] Top surface 232

[0059] Second side 233

[0060] Electrode assembly 3

[0061] Tab 31

[0062] Coating sheet 4

[0063] Part 141

[0064] Part 242

[0065] Part 343

[0066] Part 44

[0067] Part 545

[0068] Welding Mark 5

[0069] First converging plate 61

[0070] The length of the positioning portion of the second converging plate 62 is a1, the length of the weld mark is a2, the width of the positioning portion is b1, the width of the weld mark is b2, the height of the positioning portion is c1, the thickness of the connecting plate is c2, the thickness of the covering sheet is c3, the height direction H of the cover plate assembly, the length direction L of the connecting plate, and the width direction W of the connecting plate.

[0071] The first angle α

[0072] The second angle β

[0073] The center line P in the longitudinal direction of the top surface DETAILED DESCRIPTION

[0074] The following describes in detail embodiments of the present invention, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and should not be construed as limiting the present invention. All other embodiments obtained by persons of ordinary skill in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0075] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "circumferential", "radial", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0076] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature specified as "first" or "second" may explicitly or implicitly include one or more of such features. In the description of this utility model, "plurality" means two or more, unless otherwise specifically defined.

[0077] This embodiment provides a single cell battery. The single cell battery includes: a housing, a cover plate assembly, an electrode assembly, and a covering sheet. The cover plate assembly is disposed on the housing and defines a receiving cavity with the housing. The electrode assembly is received in the receiving cavity.

[0078] like Figures 1 to 6 As shown, the cover plate assembly 1 includes a cover plate body 10 and an electrode terminal 20. The cover plate body 10 has a through-hole extending therethrough. The electrode terminal 20 includes a through-portion 21 and a connecting plate 22, which are connected to each other. The through-portion 21 at least partially extends through the through-hole. The connecting plate 22 is located on the side of the cover plate body 10 facing the electrode assembly 3. The side of the connecting plate 22 facing the electrode assembly 3 is provided with a positioning portion 23 that protrudes toward the electrode assembly 3.

[0079] The tab 31 of the electrode assembly 3 is covered on the positioning portion 23 .

[0080] The covering sheet 4 matches the shape of the positioning portion 23. The covering sheet 4 is covered on the side of the pole ear 31 away from the positioning portion 23, and the pole ear 31 is pressed between the covering sheet 4 and the positioning portion 23. Along the height direction H of the cover plate assembly 1, the covering sheet 4, the pole ear 31, and the positioning portion 23 are welded together.

[0081] By pressing the tab 31 between the cover sheet 4 and the positioning portion 23 and then welding the cover sheet 4, tab 31, and positioning portion 23 along the height direction H of the cover plate assembly 1, the pre-welding process for the tab 31 can be eliminated, and the tab 31 can be directly laser-welded to the connecting plate 22 of the electrode terminal 20. This saves process costs while avoiding the foreign matter control issues associated with ultrasonic processing, indirectly improving product yield and ensuring that the battery's current capacity is not affected. Furthermore, pressing the tab 31 between the matching cover sheet 4 and positioning portion 23 not only ensures that the tab 31 is pressed tightly without pre-welding, but also ensures that the tab 31 is not damaged by the pressing action. The cover sheet 4, tab 31, and positioning portion 23 are all made of metal. It should be noted that the through-portion 21 passes through the terminal post through-hole of the cover plate body 10, thereby electrically connecting the tab 31 to the electrical connection components located outside the cover plate body 10. The through-portion 21 is typically cylindrical.

[0082] Preferably, along the height direction H of the cap plate assembly 1, the orthographic projection of the weld mark 5 formed by the weld connection of the cover sheet 4, the tab 31, and the positioning portion 23 is located within the outer periphery of the positioning portion 23. Thus, by setting the orthographic projection of the weld mark 5 within the outer periphery of the positioning portion 23, a better weld connection can be ensured between the cover sheet 4, the tab 31, and the positioning portion 23. The height direction H of the cap plate assembly 1 is in the same direction as the height direction of the single battery.

[0083] It should be noted that in order to better demonstrate the positional relationship between the welding mark 5 and the covering sheet 4, the tab 31, and the positioning portion 23, Figures 1 to 3 In the figure, the electrode assembly 3 is located at the welding position, that is, the electrode assembly 3 has not yet been rotated 90 degrees upward and installed in the shell.

[0084] Along the height direction H of the cover plate assembly 1, the orthographic projection of the covering sheet 4 is located inside the outer periphery of the connecting plate 22. In this way, by setting the orthographic projection of the covering sheet 4 inside the outer periphery of the connecting plate 22, the covering sheet 4 is prevented from interfering with surrounding components.

[0085] The weld mark 5 extends in the same direction as the positioning portion 23 and the length direction L of the connecting plate 22, providing a larger pressure-bearing surface and thus strengthening the weld. The length direction L of the connecting plate 22, i.e., the direction of the long side of the connecting plate 22, is arranged in the same direction as the length direction of the cover plate assembly 1.

[0086] Preferably, the length a2 of the weld mark 5 is greater than or equal to 30% of the length a1 of the positioning portion 23 and less than or equal to 60% of the length a1 of the positioning portion 23; the width b2 of the weld mark 5 is greater than or equal to 50% of the width b1 of the positioning portion 23 and less than the width b1 of the positioning portion 23. Thus, by setting a range of values ​​for the ratio of the size of the weld mark 5 to the size of the positioning portion 23, it is possible to avoid the weld mark 5 being too small, thereby affecting the weld strength, and the weld mark 5 being too large, thereby causing damage to surrounding components due to the heat during welding.

[0087] Specifically, the shapes of the welding mark 5 and the positioning portion 23 are both long strips. In this way, by setting the shapes of the welding mark 5 and the positioning portion 23 to be long strips, a larger pressure-bearing surface can be provided, thereby making the welding more firm.

[0088] Please refer back to Figures 4 to 6 In this embodiment, along the width direction W of the connecting plate 22, the surface of the positioning portion 23 includes a first side surface 231, a top surface 232, and a second side surface 233, which are sequentially connected. The first side surface 231 extends obliquely toward the center of the top surface 232 from an end distal to the top surface 232 to an end proximal to the top surface 232. The plane of the top surface 232 is parallel to the plane of the connecting plate 22. The second side surface 233 extends obliquely toward the center of the top surface 232 from an end distal to the top surface 232 to an end proximal to the top surface 232. The first side surface 231 and the second side surface 233 are symmetrically arranged about the centerline P of the longitudinal direction of the top surface 232. The width direction W of the connecting plate 22, i.e., a direction perpendicular to the longitudinal direction L of the connecting plate 22, is arranged in the same direction as the width direction of the cover plate assembly 1. The longitudinal direction of the top surface 232 is in the same direction as the longitudinal direction L of the connecting plate 22.

[0089] The first side surface 231 forms a first angle α with the plane of the connecting plate 22, and the first angle α is in the range of 30 degrees to 60 degrees. Thus, by setting a value range for the first angle α, it is possible to prevent the first side surface 231 from being tilted too much, which could easily damage the tab 31 pressed between the covering sheet 4 and the positioning portion 23, and from being too small, which would not achieve the desired compression effect.

[0090] The second side surface 233 forms a second angle β with the plane of the connecting plate 22, and the second angle β is in the range of 30 degrees to 60 degrees. Thus, by setting the value range of the second angle β, it is possible to avoid that the second side surface 233 is tilted too much, which may easily damage the tab 31 pressed between the covering sheet 4 and the positioning portion 23, and that the tilt angle is too small, which may not achieve the desired compression effect.

[0091] Preferably, the first side surface 231 and the second side surface 233 are symmetrically arranged with respect to the top surface 232 , so as to better achieve the clamping effect on the tab 31 .

[0092] like Figure 7 and Figure 8 As shown, along the width direction W of the connecting plate 22, the covering sheet 4 includes a first portion 41, a second portion 42, a third portion 43, a fourth portion 44, and a fifth portion 45, which are sequentially connected. The first portion 41 and the fifth portion 45 are both provided corresponding to the connecting plate 22, the second portion 42 is provided corresponding to the first side surface 231 of the positioning portion 23, the third portion 43 is provided corresponding to the top surface 232 of the positioning portion 23, and the fourth portion 44 is provided corresponding to the second side surface 233 of the positioning portion 23. In this way, by providing the specific structure of the covering sheet 4, the tab 31 can be better pressed between the covering sheet 4 and the positioning portion 23, and the tab 31 can be better protected.

[0093] Preferably, along the height direction H of the cover plate assembly 1, the height c1 of the positioning portion 23 is greater than or equal to 20% of the thickness c2 of the connecting plate 22 and less than or equal to 50% of the thickness c2 of the connecting plate 22. Thus, by setting a range of values ​​for the height c1 of the positioning portion 23, it is possible to prevent the height c1 of the positioning portion 23 from being too high, thereby occupying too much internal space of the battery, and the height c1 of the positioning portion 23 from being too low, thereby failing to provide a compacting effect.

[0094] Along the height direction H of the cover plate assembly 1 , the thickness c3 of the covering sheet 4 is less than or equal to 0.2 mm to prevent the covering sheet 4 from being too thick and causing the tab 31 to be not pressed tightly, which indirectly causes process defects in the subsequent laser welding step.

[0095] Specifically, the covering sheet 4, the tab 31, and the positioning portion 23 are connected by laser welding. The laser welding nozzle acts on the covering sheet 4, and the shape of the nozzle matches the shape of the covering sheet 4. In this way, by setting the shape of the laser welding nozzle to match the shape of the covering sheet 4, it is possible to press the tab 31 against the covering sheet 4 while ensuring that the tab 31 is not cracked. However, the present invention is not limited to this. In other embodiments, the covering sheet 4, the tab 31, and the positioning portion 23 can also be welded together using other welding methods.

[0096] The pressure exerted by the pressure nozzle on the covering sheet 4 is less than or equal to 800 kg. Thus, since the top cover assembly is assembled from multiple components, by setting a value range for the pressure exerted by the pressure nozzle on the covering sheet 4, it is possible to avoid excessive pressure exerted by the pressure nozzle, which may cause failure of the connection between multiple components and thus affect the overall sealing of the finalization assembly.

[0097] In this embodiment, the welding process of the tab 31 and the connecting plate 22 includes the following steps:

[0098] Step 100: shaping the tab 31 of the electrode assembly 3;

[0099] Step 200: Lay the tabs 31 onto the positioning portions 23 of the connecting plate 22 in sequence, and place the covering sheet 4 at a preset position on the tabs 31 so that the covering sheet 4 and the positioning portions 23 are aligned, so that the tabs 31 can be clamped between the covering sheet 4 and the positioning portions 23 in the following steps.

[0100] Step 300: Press the cover sheet 4 with a laser welding nozzle, thereby achieving compression of the cover sheet 4 and the positioning portion 23 against the tab 31;

[0101] Step 400: Laser aligns with the protruding surface of the cover sheet 4 to perform laser welding, so that the cover sheet 4, the tab 31 and the positioning portion 23 are welded into a whole;

[0102] Step 500: Rotate the electrode assembly 3 upward by 90 degrees and install it into the shell.

[0103] In step 100, in the step of shaping the tab 31 of the electrode assembly 3, as shown in FIG. Figure 9 As shown, the first and second converging plates 61 and 62 are used to shape and converge the originally loose tabs 31, so that the tabs 31 are converged in a fixed position as a whole. Figure 10 Through step 100 , the subsequent laser welding requirements for the tab 31 can be met.

[0104] In step 300, the special structural design of the bottom of the laser-welded pressing nozzle can compress the tab 31 and the protective sheet while ensuring that the tab 31 is not cracked. In the process of the pressing nozzle pressing the cover sheet 4 and the tab 31, to ensure the sealing of the top cover assembly, the maximum pressure on the pressure-bearing part during the press-fitting process should not exceed 800 kg.

[0105] In this embodiment, by pressing the tab 31 between the cover sheet 4 and the positioning portion 23, and welding the cover sheet 4, tab 31, and positioning portion 23 along the height direction H of the cover plate assembly 1, the pre-welding process can be eliminated, and the tab 31 can be directly laser welded to the connecting plate 22 of the electrode terminal 20. This saves process costs while avoiding the foreign matter control issues of the ultrasonic process, indirectly improving product yield, and ensuring that the battery's current capacity is not affected. Furthermore, pressing the tab 31 between the cover sheet 4 and the positioning portion 23, which have matching shapes, not only meets the requirements of compacting the tab 31 without pre-welding, but also ensures that the tab 31 will not be damaged by the compaction action.

[0106] Although specific embodiments of the present invention have been described above, those skilled in the art will appreciate that these are merely illustrative and that the scope of protection of the present invention is defined by the appended claims. Those skilled in the art may make various changes or modifications to these embodiments without departing from the principles and essence of the present invention, and such changes and modifications are intended to fall within the scope of protection of the present invention.

Claims

1. A single battery, characterized in that: It includes: case; a cover plate assembly, which is disposed on the housing and defines a receiving cavity together with the housing; the cover plate assembly includes a cover plate body and an electrode terminal; the cover plate body has a through-hole for a pole; the electrode terminal includes a through-portion and a connecting plate connected thereto; the through-portion at least partially penetrates the through-hole for the pole; the connecting plate is located on a side of the cover plate body facing the electrode assembly; and a positioning portion protruding toward the electrode assembly is provided on the side of the connecting plate facing the electrode assembly; an electrode assembly accommodated in the accommodation cavity, with the tab of the electrode assembly covering the positioning portion; The covering sheet matches the shape of the positioning portion, and the covering sheet is covered on the side of the pole ear away from the positioning portion, and the pole ear is pressed between the covering sheet and the positioning portion. Along the height direction of the cover plate assembly, the covering sheet, the pole ear, and the positioning portion are welded together.

2. The single cell according to claim 1, wherein: Along the height direction of the cover plate assembly, the orthographic projection of the weld mark formed by welding the covering sheet, the tab, and the positioning portion is located within the outer periphery of the positioning portion; and / or, Along the height direction of the cover plate assembly, the orthographic projection of the covering sheet is located within the outer periphery of the connecting plate.

3. The single cell according to claim 2, wherein: The extending direction of the welding mark is the same as the extending direction of the positioning portion and the same as the length direction of the connecting plate.

4. The single cell according to claim 3, wherein: The length of the weld mark is greater than or equal to 30% of the length of the positioning portion and less than or equal to 60% of the length of the positioning portion; and / or, The width of the weld mark is greater than or equal to 50% of the width of the positioning portion and is smaller than the width of the positioning portion.

5. The single cell according to claim 3, wherein: The shapes of the welding mark and the positioning portion are both long strips.

6. The single cell according to claim 3, wherein: Along the width direction of the connecting plate, the surface of the positioning portion includes a first side surface, a top surface and a second side surface connected in sequence, the first side surface extends obliquely toward the center position of the top surface from an end away from the top surface to an end close to the top surface, the plane where the top surface is located is parallel to the plane where the connecting plate is located, the second side surface extends obliquely toward the center position of the top surface from an end away from the top surface to an end close to the top surface, and the first side surface and the second side surface are symmetrically arranged about the center line of the longitudinal direction of the top surface.

7. The single cell according to claim 6, wherein: The first side surface forms a first angle with the plane where the connecting plate is located, and the first angle is 30 degrees to 60 degrees; and / or, The second side surface forms a second angle with the plane where the connecting plate is located, and the second angle is 30 degrees to 60 degrees.

8. The single cell according to claim 6, wherein: Along the width direction of the connecting plate, the covering sheet includes a first part, a second part, a third part, a fourth part, and a fifth part connected in sequence, the first part and the fifth part are both arranged corresponding to the connecting plate, the second part is arranged corresponding to the first side surface of the positioning part, the third part is arranged corresponding to the top surface of the positioning part, and the fourth part is arranged corresponding to the second side surface of the positioning part.

9. The single cell according to claim 1, wherein: Along the height direction of the cover plate assembly, the height of the positioning portion is greater than or equal to 20% and less than or equal to 50% of the thickness of the connecting plate; and / or, Along the height direction of the cover plate assembly, the thickness of the covering sheet is less than or equal to 0.2 mm.

10. The single cell according to any one of claims 1 to 9, characterized in that: The covering sheet, the tab, and the positioning portion are connected by laser welding, and a laser welding nozzle acts on the covering sheet, and the shape of the nozzle matches the shape of the covering sheet.

11. The single cell according to claim 10, wherein: The pressure exerted by the pressure nozzle on the covering sheet is less than or equal to 800 kg.

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