CN115815368A

CN115815368A - Lug flattening device

Info

Publication number: CN115815368A
Application number: CN202210187360.1A
Authority: CN
Inventors: 余仁鹏
Original assignee: Contemporary Amperex Technology Co Ltd
Current assignee: Contemporary Amperex Technology Co Ltd
Priority date: 2022-02-28
Filing date: 2022-02-28
Publication date: 2023-03-21
Also published as: WO2023160707A1

Abstract

A tab flattening apparatus is provided that includes a clamp and a sleeve assembly. The clamp is used to clamp the electrode assembly in a radial direction. The sleeve component comprises a furling part, a limiting part and a propelling part. The furling part is used for moving along a first direction so as to furl the electrode lugs of the electrode assembly towards a direction close to the electrode assembly, and the first direction is parallel to the axis of the electrode assembly and faces the clamp. The limiting part is connected with the first end of the furling part, the first end faces the clamp, and the limiting part is used for surrounding the electrode assembly when the furling part moves along the first direction and is abutted to the clamp after the electrode lugs are furled. The pushing part is arranged at the second end of the collecting part, the second end is far away from the clamp, the pushing part is used for extruding the tab along the first direction after the tab is collected so as to flatten the tab to a preset tab height, and the tab height refers to the height of the tab protruding out of the end face of a non-polar tab area of the electrode assembly along the axial direction of the electrode assembly. According to the technical scheme, the performance of the battery can be improved, and the safety performance is guaranteed.

Description

Lug flattening device

Technical Field

The application relates to the field of batteries, in particular to a lug flattening device.

Background

With the increasing environmental pollution, the new energy industry is receiving more and more attention. In the new energy industry, battery technology is an important factor regarding its development.

The energy density is one of important indexes of the battery performance, and the lug on the electrode assembly of the battery is flattened, so that the space occupation ratio of the lug can be effectively reduced, and the energy density of the battery is improved. Meanwhile, flattening the tab may cause the tab to turn outwards without being folded, thereby causing short circuit, or metal particles generated by friction during flattening process affect the performance of the battery and even cause safety problems. Therefore, the process of flattening the tabs and the quality after flattening directly affect the quality and safety of the electrode assembly. Therefore, how to provide a tab flattening device, which improves the quality of flattening tabs while ensuring the energy density of a battery, thereby improving the performance of the battery and ensuring the safety performance, is a problem to be solved urgently in the battery technology.

Disclosure of Invention

The application provides a flat device is rubbed to utmost point ear improves when guaranteeing the energy density of battery and rubs the quality of flat utmost point ear to promote the performance of battery, ensure the safety of battery.

The application provides a flat device is rubbed to utmost point ear includes: a clamp for clamping the cylindrical electrode assembly in a radial direction; a sleeve assembly, comprising: the furling part is used for moving along a first direction to furl the electrode lugs of the electrode assembly to a direction close to the electrode assembly, and the first direction is parallel to the axis of the electrode assembly and faces the clamp; the limiting part is connected with a first end of the furling part, the first end of the limiting part faces the clamp, the first end of the furling part faces one end of the clamp, and the limiting part is used for surrounding the electrode assembly when the furling part moves along the first direction and is abutted to the clamp after the tab is furled; the pole lug pressing device comprises a pushing part, wherein the pushing part is arranged at the second end of the furling part, the second end is far away from the clamp pushing part, the clamp pushing part is arranged at one end, far away from the clamp, of the furling part, the pushing part is used for squeezing the pole lug in the first direction after the pole lug is furled so as to flatten the pole lug to a preset lug height, and the lug height is the height of the pole lug protruding out of the end face of a non-pole lug area of the electrode assembly in the axial direction of the electrode assembly.

In an embodiment of the present application, a clamp is used to clamp the electrode assembly and a sleeve assembly is used to flatten the tabs. Draw in the utmost point ear through the portion of drawing in and draw in to preset the position, later through spacing portion surround electrode subassembly and with anchor clamps butt, fix electrode subassembly like this in the axial direction to be favorable to propulsion portion extrusion utmost point ear to presetting the ear height. Through the arrangement, the electrode assembly can be prevented from moving along the axial direction in the process of extruding the tab, so that the deviation between the actual ear height and the preset ear height of the tab caused by the axial deviation of the tab is prevented, and the flattening precision of the tab is improved. Meanwhile, the lug is flattened in an extrusion mode, so that metal particles generated by the lug in the flattening process can be reduced, the short circuit caused by the fact that the metal particles pierce the isolating film between the positive plate and the negative plate is avoided, and the problems of capacity reduction, insufficient voltage and the like of the battery caused by abnormal self-discharge of the battery due to the metal particles can be avoided. Therefore, the technical scheme of the embodiment of the application can improve the quality of flattening the lug while ensuring the energy density of the battery, thereby improving the performance of the battery and ensuring the safety performance of the battery.

In a possible implementation manner, the furling part and the limiting part are cylindrical, the diameter of the furling part is gradually reduced from the first end to the second end, and the diameter of the limiting part is the same as that of the furling part at the first end. Thus, the collected tabs are gradually gathered towards the center, namely towards the axis of the electrode assembly. The tab is folded before the tab is extruded, so that the condition that the tab turns outwards in the extrusion process can be avoided, and the short circuit risk caused by the turning outwards of the tab is avoided.

In one possible implementation, the gathering part is in a curved tubular shape. Therefore, the process of drawing the pole lug is smoother, the pole lug is gradually gathered towards the center, and the possibility of outward turning of the pole lug is further reduced; in addition, the folded electrode lugs are more uniform, and the follow-up extrusion process is facilitated.

In one possible implementation, the diameter of the electrode assembly is smaller than the diameter of the furl at the first end than the diameter of the furl at the second end. In this way, the electrode assembly may be received in the stopper while the drawing-in of the tabs may be accomplished.

In one possible implementation, the diameter of the limiting portion is 3mm to 5mm larger than the diameter of the converging portion at the second end. Therefore, the pole lugs can be folded in a certain range.

In one possible implementation, the diameter of the stopper portion is 10mm to 14mm larger than the diameter of the electrode assembly before flattening. In this way, the electrode assembly can be enclosed in the position restricting portion in an appropriate range while avoiding the electrode assembly from shifting in the radial direction due to an excessively large diameter of the position restricting portion, i.e., the position restricting portion effects the position restriction of the electrode assembly in the radial direction.

In one possible implementation, the propelling part comprises a propelling surface, a propelling rod and a propelling barrel; wherein the pusher barrel is connected to the second end of the furl portion, the pusher barrel having a diameter that is the same as the diameter of the furl portion at the second end; the pushing rod is connected with the pushing surface and used for pushing the pushing surface to move in the first direction in the pushing cylinder so as to extrude the tab. Therefore, under the action of the pushing rod, the pushing surface moves in the pushing cylinder along the first direction so as to extrude the folded lug in the pushing cylinder to the preset lug height. In addition, the propelling distance of the propelling surface can be controlled, and the ear height of the kneaded flat tab can be flexibly controlled.

In one possible implementation, the length of the jig in the first direction is 30% to 50% of the length of the electrode assembly before flattening. Thus, the contact area of the clamp and the electrode assembly is reduced, which is beneficial to improving the roundness of the electrode assembly and reducing the deformation of the electrode assembly along the radial direction.

In one possible implementation, a first surface of the clamp is provided with an anti-slip structure for increasing a frictional force between the electrode assembly and the clamp in the first direction, wherein the first surface is a surface of the clamp contacting the electrode assembly. Therefore, the friction force between the clamp and the electrode assembly along the first direction can be increased, and the stability of the electrode assembly along the axial direction in the tab extrusion process is enhanced.

In one possible implementation, the non-slip structure is rubber particles. For example, the rubber particles are uniformly distributed on the first surface of the clamp, so that the friction force between the electrode assembly and the clamp is more uniform, and the electrode assembly is limited in the first direction.

In a possible implementation, the clamp has an abutment surface perpendicular to the first direction, the abutment surface being configured to abut the limiting portion. Like this, spacing portion and anchor clamps are face contact, have increased the butt power between butt portion and the anchor clamps, are favorable to maintaining sleeve subassembly's stability.

In one possible implementation manner, in the first direction, the sum of the lengths of the limiting part and the furling part is less than half of the difference between the length of the electrode assembly before flattening and the length of the clamp. Thus, the tab can be pressed from the initial state to a preset tab height.

In an embodiment of the present application, a clamp is used to clamp the electrode assembly and a sleeve assembly is used to flatten the tabs. Draw in the portion through drawing in and draw in utmost point ear to preset the position, later the spacing portion of rethread surrounds electrode subassembly and with anchor clamps butt, fix electrode subassembly on axial direction like this to be favorable to propulsion portion extrusion utmost point ear to presetting the ear height. Through the arrangement, the electrode assembly can be prevented from moving along the axial direction in the process of extruding the tab, so that the deviation between the actual ear height and the preset ear height of the tab caused by the axial deviation of the tab is prevented, and the flattening precision of the tab is improved. Meanwhile, the lug is flattened in an extrusion mode, so that metal particles generated by the lug in the flattening process can be reduced, the short circuit caused by the fact that the metal particles pierce an isolating film between the positive plate and the negative plate is avoided, and the problems of battery capacity reduction, insufficient voltage and the like caused by abnormal self-discharge of the battery due to the metal particles can be avoided. Therefore, the technical scheme of the embodiment of the application can improve the quality of flattening the lug while ensuring the energy density of the battery, thereby improving the performance of the battery and ensuring the safety performance of the battery.

Drawings

FIG. 1 is a schematic illustration of a vehicle according to an embodiment of the present application;

FIG. 2 is a schematic diagram of a battery according to an embodiment of the present application;

FIG. 3 is a schematic diagram of a battery cell according to an embodiment of the present application;

fig. 4 is a schematic view of a tab flattening apparatus according to an embodiment of the present application;

fig. 5 is a schematic view of a tab flattening apparatus after tab collection in accordance with an embodiment of the present application;

fig. 6 is a schematic view of a tab before and after flattening in accordance with an embodiment of the present application;

FIG. 7 is a schematic view of a sleeve assembly according to an embodiment of the present application.

Detailed Description

The technical solutions in the embodiments of the present application will be described below with reference to the accompanying drawings. The following examples are merely used to more clearly illustrate the technical solutions of the present application, and therefore are only examples, and the protection scope of the present application is not limited thereby.

The following detailed description of the embodiments and the accompanying drawings are provided to illustrate the principles of the application and are not intended to limit the scope of the application, i.e., the application is not limited to the described embodiments.

In the description of the present application, it is to be noted that, unless otherwise specified, all technical and scientific terms used have the same meaning as commonly understood by one of ordinary skill in the art to which the present application belongs; the terminology used is for the purpose of describing particular embodiments only and is not intended to be limiting of the application; the terms "including" and "having," and any variations thereof, in the description and claims of this application and the description of the above figures, are intended to cover non-exclusive inclusions; "plurality" means two or more; the terms "upper," "lower," "left," "right," "inner," "outer," and the like, indicate an orientation or positional relationship that is merely for convenience in describing the application and to simplify the description, and do not indicate or imply that the referenced devices or elements must have a particular orientation, be constructed and operated in a particular orientation, and thus should not be construed as limiting the application. Furthermore, the terms "first," "second," "third," and the like are used for descriptive purposes only and are not to be construed as indicating or implying relative importance. "vertical" is not strictly vertical, but is within the tolerance of the error. "parallel" is not strictly parallel but is within the tolerance of the error.

Reference in the specification to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the specification. The appearances of the phrase in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments. It is explicitly and implicitly understood by one skilled in the art that the embodiments described herein can be combined with other embodiments.

The directional terms used in the following description are intended to refer to directions shown in the drawings, and are not intended to limit the specific structure of the present application. In the description of the present application, it is also to be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meaning of the above terms in the present application can be understood by those of ordinary skill in the art as the case may be.

The term "and/or" in this application is only one kind of association relationship describing the associated object, and means that there may be three kinds of relationships, for example, a and/or B, which may mean: a exists alone, A and B exist simultaneously, and B exists alone. In addition, the character "/" in this application generally indicates that the former and latter related objects are in an "or" relationship.

In the present application, the battery cell may include a lithium ion secondary battery, a lithium ion primary battery, a lithium sulfur battery, a sodium lithium ion battery, a sodium ion battery, a magnesium ion battery, or the like, which is not limited in the embodiments of the present application. Reference to a battery in embodiments of the present application refers to a physical module that includes one or more battery cells to provide electrical energy. For example, the battery referred to in the present application may include a battery pack or the like. Batteries generally include a case for enclosing one or more battery cells. The box can avoid liquid or other foreign matters to influence the charging or discharging of battery monomer.

The battery monomer comprises an electrode assembly and electrolyte, wherein the electrode assembly comprises a positive plate, a negative plate and an isolating membrane. The battery cell mainly depends on metal ions moving between the positive plate and the negative plate to work. The positive plate comprises a positive current collector and a positive active substance layer, wherein the positive active substance layer is coated on the surface of the positive current collector, the current collector which is not coated with the positive active substance layer protrudes out of the current collector which is coated with the positive active substance layer, and the current collector which is not coated with the positive active substance layer is used as a positive pole lug. Taking a lithium ion battery as an example, the material of the positive electrode current collector may be aluminum, and the positive electrode active material may be lithium cobaltate, lithium iron phosphate, ternary lithium, lithium manganate, or the like. The negative pole piece includes negative current collector and negative pole active substance layer, and the negative pole active substance layer coats in the surface of negative current collector, and the mass flow body protrusion in the mass flow body of coating the negative pole active substance layer of uncoated negative pole active substance layer, the mass flow body of uncoated negative pole active substance layer is as negative pole utmost point ear. The material of the negative electrode collector may be copper, and the negative electrode active material may be carbon, silicon, or the like. The material of the isolation film can be polypropylene (PP), polyethylene (PE) or the like.

In order to meet different power requirements, a plurality of battery cells in the battery can be connected in series, in parallel or in series-parallel, wherein series-parallel refers to a mixture of series connection and parallel connection. Alternatively, a plurality of battery cells may be connected in series, in parallel, or in series-parallel to form a battery module, and a plurality of battery modules may be connected in series, in parallel, or in series-parallel to form a battery. That is, a plurality of battery cells may directly constitute a battery, or a battery module may be first constituted and then a battery may be constituted. The battery is further arranged in the electric equipment to provide electric energy for the electric equipment.

At present, the application of the power battery is more and more extensive from the development of market situation. The power battery is not only applied to energy storage power supply systems such as hydraulic power, firepower, wind power and solar power stations, but also widely applied to electric vehicles such as electric bicycles, electric motorcycles, electric automobiles and the like, and a plurality of fields such as military equipment and aerospace. With the continuous expansion of the application field of the power battery, the market demand is also continuously expanding. Among them, the cylindrical battery is also increasingly used.

In the production process of the cylindrical battery, an important process is to prepare the tab. For the cylindrical battery with the full tab structure, when the positive and negative current collectors are coated with the positive active material layer and the negative active material layer, a piece of empty foil area is left at the edge of the positive and negative current collectors, and the empty foil area is used as a tab. After coating, the positive and negative current collectors are wound and the empty foil areas, i.e., the tabs, are kneaded flat. At the flat in-process of rubbing of utmost point ear, can appear that the utmost point ear turns up, the utmost point ear surface appears metal granule, utmost point ear and predetermines phenomenon such as highly and actual height difference, and the production of these phenomena all can influence the quality of utmost point ear, and then influences the battery performance.

Based on the consideration, the application provides a lug flattening device, which comprises a clamp and a sleeve assembly, wherein the clamp and a limiting part in the sleeve assembly are matched with each other to limit an electrode assembly in the axial direction of the electrode assembly; the portion of drawing in among the sleeve assembly can draw in the utmost point ear in to the utmost point ear after the portion's of pushing in extrusion draws in the sleeve assembly, thereby avoided kneading flat in-process utmost point ear and turned up the short circuit that leads to, simultaneously, the kneading of utmost point ear is flat to be realized through the extrusion, has reduced and has kneaded flat in-process metal particle's production, has avoided the emergence of phenomenon such as self discharge abnormity. Therefore, the technical scheme of the embodiment of the application can improve the quality of the pole lug, so that the performance of the battery is improved.

The technical solutions described in the embodiments of the present application are applicable to a cylindrical battery cell, and the cylindrical battery cell is applicable to various devices using a battery, such as a mobile phone, a portable device, a notebook computer, a battery car, an electric toy, an electric tool, an electric vehicle, a ship, a spacecraft, and the like, for example, a spacecraft including an airplane, a rocket, a space shuttle, a spacecraft, and the like.

It should be understood that the technical solutions described in the embodiments of the present application are not limited to be applied to the above-described devices, but may also be applied to all devices using batteries, and for brevity of description, the following embodiments are all described by taking an electric vehicle as an example.

For example, as shown in fig. 1, fig. 1 is a schematic structural diagram of a vehicle 1 according to an embodiment of the present application. The vehicle 1 can be a fuel automobile, a gas automobile or a new energy automobile, and the new energy automobile can be a pure electric automobile, a hybrid electric automobile or a range-extended automobile and the like. The vehicle 1 may be provided with a motor 40, a controller 30 and a battery 10, the controller 30 being configured to control the battery 10 to supply power to the motor 40. For example, the battery 10 may be provided at the bottom or the head or tail of the vehicle 1. The battery 10 may be used for power supply of the vehicle 1, for example, the battery 10 may be used as an operation power supply of the vehicle 1 for a circuit system of the vehicle 1, for example, for power demand for operation at the start, navigation, and running of the vehicle 1. In another embodiment of the present application, the battery 10 may be used not only as an operation power source of the vehicle 1 but also as a driving power source of the vehicle 1 instead of or in part of fuel or natural gas to provide driving power to the vehicle 1.

In order to meet different power usage requirements, the battery 10 may include a plurality of battery cells. For example, as shown in fig. 2, the battery 10 may include a plurality of battery cells 20 for a structural schematic diagram of the battery 10 according to an embodiment of the present disclosure. The battery 10 may further include a case 11, the inside of the case 11 is a hollow structure, and the plurality of battery cells 20 are accommodated in the case 11. For example, a plurality of battery cells 20 are connected in parallel or in series or in a combination of series and parallel to each other and then placed in the case 11. The case 11 may include a first case portion 111 and a second case portion 112 as long as they can accommodate the battery cells, and is not particularly limited herein.

Optionally, the battery 10 may also include other structures, which are not described in detail herein. For example, the battery 10 may further include a bus member for achieving electrical connection between the plurality of battery cells 20, such as parallel connection or series-parallel connection. Specifically, the bus member may achieve electrical connection between the battery cells 20 by connecting electrode terminals of the battery cells 20. Further, the bus bar member may be fixed to the electrode terminals of the battery cells 20 by welding. The electric energy of the plurality of battery cells 20 can be further led out through the box body by the conductive mechanism. Alternatively, the conductive means may also belong to the bus bar member.

The number of the battery cells 20 may be set to any number according to different power requirements. A plurality of battery cells 20 may be connected in series, parallel, or series-parallel to achieve greater capacity or power. Since the number of the battery cells 20 included in each battery 10 may be large, the battery cells 20 may be arranged in groups for convenience of installation, each group of the battery cells 20 constituting a battery module. The number of the battery cells 20 included in the battery module is not limited and may be set as required. The battery may include a plurality of battery modules, which may be connected in series, parallel, or series-parallel.

Fig. 3 is a schematic structural diagram of a battery cell 20 according to an embodiment of the present disclosure. The battery cell 20 includes a case 21, an end cap 22, and an electrode assembly 23. The housing 21 and the end cap 22 form an outer shell or battery case, and the walls of the housing 21 and the end cap 22 are referred to as the walls of the battery cell 20. The case 21 is determined according to the shape of one or more electrode assemblies 23 after being assembled. For example, the housing 21 may be a hollow cylinder as shown in fig. 3, or if the battery cell 20 is a blade type battery cell, the housing 21 may be a rectangular parallelepiped with a long length. And at least one face of the case 21 has an opening so that one or more electrode assemblies 23 are placed in the case 21. For example, when the housing 21 is a hollow cylinder, the end surface of the housing 21 is an open surface, that is, the end surface has no wall body so that the housing 21 communicates with the inside and the outside. As can be seen in fig. 3, the cylindrical battery cell has two circular end surfaces between which a cylindrical body is formed, and the cylindrical body may include an electrode assembly 23. The end cap 22 covers the opening and is connected with the case 21 to form a closed cavity that prevents the electrode assembly 23. The case 21 is filled with an electrolyte, such as an electrolytic solution.

The end cap 22 may be provided with an electrode terminal 24, and the electrode terminal 24 is electrically connected to a component other than the battery cell 20, alternatively, as shown in the embodiment of the present application, the battery cell 20 may have one electrode terminal 24 at each of two ends, and the electrode terminal 24 may be a protrusion 222 formed by the end cap 22; alternatively, one end of the battery cell 20 may be configured as described above, and the other end may be electrically connected to the electrode terminal 24 formed by the case 21 or the electrode post.

In the battery cell 20, the electrode assembly 23 may be provided singly or in multiple numbers according to actual use requirements, and in some embodiments of the present application, as shown in fig. 3, one electrode assembly 23 is disposed in the battery cell 20.

Fig. 4 is a schematic view of a tab flattening apparatus according to an embodiment of the present application. As shown in fig. 4, the tab flattening apparatus 400 includes a jig 30 and a sleeve assembly 50. The clamps 30 are used to clamp the cylindrical electrode assembly 23 in the radial direction. The sleeve assembly 50 includes a limiting portion 501, a converging portion 502 and a pushing portion 503. The withdrawing part 502 is used to move in a first direction parallel to the axis 231 of the electrode assembly 23 and toward the jig 30 to withdraw the tab 201 of the electrode assembly 23 in a direction approaching the electrode assembly 23. The stopper 501 is connected to a first end of the folded part 502, the first end faces the jig 30, and the stopper 501 surrounds the electrode assembly 23 when the folded part 502 moves in the first direction and abuts against the jig 30 after the tabs 201 are folded. The pushing part 503 is disposed at a second end of the furled part 502, the second end is far away from the clamp 30, the pushing part 503 is used for pressing the tab 201 along the first direction after the tab 201 is furled so as to flatten the tab 201 to a preset ear height, which is the height of the tab protruding from the end surface 23a of the non-tab area of the electrode assembly 23 along the axial direction of the electrode assembly 23.

The clamp 30 clamps the electrode assembly 23 in a radial direction, for example, the clamp 30 surrounds and clamps the electrode assembly 23 in a circumferential direction of the electrode assembly 23. The clamp 30 may be a mechanical gripper or an annular clamping jaw as long as clamping and limiting of the electrode assembly 23 can be achieved. The clamp 30 may achieve a limit on the electrode assembly 23, for example, the clamp 30 may limit movement of the electrode assembly 23 in the direction of the axis 231 of the electrode assembly 23.

The first direction is parallel to the axis 231 and toward the clamp 30, as shown in fig. 3, and may be the direction shown by arrow D.

The sleeve assembly 50 includes a position-limiting portion 501, a furling portion 502 and a pushing portion 503, wherein the pushing portion 503, the furling portion 502 and the position-limiting portion 501 are sequentially connected along a first direction, that is, the position-limiting portion 501 and the furling portion 502 are connected toward a first end of the fixture 30, and the pushing portion 503 and a second end of the furling portion 502 far away from the fixture 30 are connected, wherein a distance between the first end and the fixture 30 is smaller than a distance between the second end and the fixture 30.

Fig. 5 is a schematic view of a post tab flattening apparatus with a tab folded in accordance with an embodiment of the present application. As shown in fig. 5, the pushing portion 503 is disposed at the second end of the furling portion 502. Optionally, in an embodiment, the tab 201 is folded by the folding portion 502 to a preset folding position, at this time, one end of the tab 201 contacts with the pushing portion 503, and the other end is aligned with the second end of the folding portion 502; after the tab 201 is completely closed, the stopper 501 abuts against the jig 30. The furling degree of the tab 201, namely the preset furling position, can be set according to actual requirements, and the application does not specifically limit the process.

Fig. 6 is a schematic view of a tab before and after flattening in accordance with one embodiment of the present application. As shown in fig. 6, the electrode assembly 23 includes an end face 23a and an end face 23b, wherein the end face 23a is an end face of one end of the non-electrode tab region of the electrode assembly 23, and the end face 23b is an end face of one end of the entire electrode assembly 23. Before the tab 201 is flattened, the tab 201 has an initial height equal to the vertical distance between the end surfaces 23a and 23 b. After the tab 201 is flattened, i.e. the tab is flattened to a preset ear height, the preset ear height is smaller than the initial ear height. The preset ear height can be set according to actual requirements, and the embodiment of the application does not limit the preset ear height.

During flattening of the tab 201, the gathering part 502 moves in a first direction to gather the tab 201 in a direction close to the axis 231; meanwhile, the limiting portion 501 moves along the first direction, after the tab 201 is completely folded, the limiting portion 501 abuts against the clamp 30, at this time, the limiting portion 501 surrounds the electrode assembly 23, and the sleeve assembly 50 and the clamp 30 cooperate with each other to limit the movement of the electrode assembly 23 along the axis 231. Then, the pushing part 503 moves along the first direction to press the tab 201 folded along the first direction to a predetermined tab height.

In the embodiment of the present application, the tab flattening device 400 may limit the movement of the electrode assembly 23 in the direction of the axis 231 during the extrusion process of the tab 201, and avoid the movement of the tab 201 in the direction of the axis 231 due to the movement of the electrode assembly 23, thereby avoiding the deviation between the preset ear height and the actual ear height after flattening caused by the deviation of the tab 201 during the extrusion process, and further improving the flattening accuracy of the tab 201. In addition, because the lug is flattened in an extrusion mode, metal particles generated by the lug in the flattening process can be reduced, the short circuit caused by the fact that the metal particles penetrate through an isolating film between the positive plate and the negative plate is avoided, and the problems of battery capacity reduction, insufficient voltage and the like caused by abnormal self-discharge of the battery due to the metal particles can be avoided. Therefore, the technical scheme of the embodiment of the application can improve the quality of the flattening lug 201 while ensuring the energy density of the battery, thereby improving the performance of the battery and ensuring the safety performance of the battery.

FIG. 7 is a schematic view of a sleeve assembly according to one embodiment of the present application. Optionally, in an embodiment of the present application, the furling portion 502 and the limiting portion 501 are cylindrical, a diameter of the furling portion 502 gradually decreases from the first end to the second end, and a diameter of the limiting portion 501 is the same as a diameter of the furling portion 502 at the first end.

The drawn part 502 has a cylindrical shape and a diameter gradually decreasing from a first end to a second end, so that the tab 201 is gradually drawn toward the center, i.e., toward the axis of the electrode assembly, during the process of drawing the tab 201. Draw in utmost point ear 201 before extrusion utmost point ear 201 and can avoid the condition that the utmost point ear turned up to appear in the extrusion process, avoided turning up the short circuit risk that leads to because of the utmost point ear.

Optionally, in an embodiment of the present application, the gathering portion 502 is a curved cylinder. The diameter of the furling part 502 is uniformly and gently reduced from the first end to the second end, and the surface of the furling part 502 is in a smooth curved surface shape, so that the furling process of the pole lug 201 is smoother, the pole lug 201 is gradually gathered towards the center, and the possibility of the pole lug turning outwards is further reduced; in addition, the collected tab 201 is more uniform, which is beneficial to the subsequent extrusion process.

Optionally, in one embodiment of the present application, the diameter of the electrode assembly 23 is smaller than the diameter of the furled portion 502 at the first end and larger than the diameter of the furled portion 502 at the second end. In this way, the electrode assembly 23 can be received in the stopper portion 501 while the collecting of the tab 201 can be achieved.

Optionally, in an embodiment of the present application, the diameter of the limiting portion 501 is 3mm to 5mm larger than the diameter of the gathering portion 502 at the second end. Thus, the tab 201 can be folded within a certain range. The difference between the diameter of the limiting portion 501 and the diameter of the furling portion 502 at the second end can also be set according to practical requirements, for example, the ear height of the tab, which is not particularly limited in the embodiments of the present application.

Optionally, in one embodiment of the present application, the diameter of the stopper portion 501 is 10mm to 14mm larger than the diameter of the electrode assembly 23. In this way, it is possible to surround the electrode assembly 23 in the position restricting portion 501 in an appropriate range while avoiding the electrode assembly 23 from being shifted in the radial direction due to an excessively large diameter of the position restricting portion 501, i.e., the position restricting portion 501 achieves position restriction of the electrode assembly 23 in the radial direction.

Optionally, in one embodiment of the present application, the pusher 503 comprises a pusher face 5031, a pusher stem 5032, and a pusher barrel 5033; wherein the pushing barrel 5033 is connected with the second end of the furled part 502, and the diameter of the pushing barrel 5033 is the same as the diameter of the furled part 502 at the second end; the push rod 5032 is connected to the push face 5031 and is used for pushing the push face 5031 to move in the first direction in the push barrel 5033 to press the tab 201.

The thrust surface 5031 is a slidable surface that can move within the thrust barrel 5033. The pushing rod 5032 may be a rod connecting the electric cylinder with the pushing surface 5031, that is, the electric cylinder drives the pushing surface 5031 to compact the tab 201. Thus, under the action of the push rod 5032, the push surface 5031 moves in the first direction in the push barrel 5033 to press the tab 201, which is located in the push barrel 5033 after being folded, to a preset tab height. In addition, the propelling distance of the propelling surface 5031 can be controlled, and the ear height of the flattened tab 201 can be flexibly controlled.

The length of the thrust barrel 5033 in the first direction can be set according to practical requirements, for example, the height of the tab. For different electrode assemblies 23, tabs 201 with different ear heights may be required, and the driving surface 5031 can be arranged to move in the driving barrel 5033, so that when the preset ear height of the tab 201 is changed, the tab flattening device 400 does not need to be replaced, and the position of the driving surface 5031 in the driving barrel 5033 can be changed.

Alternatively, in one embodiment of the present application, the length of the clamp 30 is 30% to 50% of the length of the electrode assembly 23 in the first direction. Thus, the contact area of the jig 30 with the electrode assembly 23 is reduced, which is advantageous for improving the roundness of the electrode assembly 23 and reducing the deformation of the electrode assembly 23 in the radial direction.

Optionally, in an embodiment of the present application, a first surface of the clamp 30 is provided with a slip prevention structure 301, and the slip prevention structure 301 is used for increasing the friction force between the electrode assembly 23 and the clamp 30 in the first direction, wherein the first surface is a surface of the clamp 30 contacting the electrode assembly 23. Thus, the frictional force of the jig 30 with the electrode assembly 23 in the first direction may be increased, enhancing the stability of the electrode assembly 23 in the axial direction during the pressing of the tab 201.

Optionally, in an embodiment of the present application, the anti-slip structure 301 is a rubber particle. For example, the rubber particles are uniformly distributed on the first surface of the jig 30, so that the friction between the electrode assembly 23 and the jig 30 is more uniform, which is beneficial to limit the electrode assembly 23 in the first direction.

Optionally, in an embodiment of the present application, the clamp 30 has an abutting surface perpendicular to the first direction, and the abutting surface is used for abutting against the limiting portion 501. Thus, the stopper 501 is in surface contact with the jig 30, which increases the abutting force between the abutting portion 501 and the jig 30, and is beneficial to maintaining the stability of the sleeve assembly 50.

Optionally, in an embodiment of the present application, in the first direction, the sum of the lengths of the position-limiting portion 501 and the furled portion 502 is less than half of the difference between the length of the electrode assembly 23 before kneading and the length of the clamp 30. In this way, it is possible to achieve the extrusion of the tab from the initial ear height to the preset ear height.

While the application has been described with reference to a preferred embodiment, various modifications may be made and equivalents may be substituted for elements thereof without departing from the scope of the application. In particular, the technical features mentioned in the embodiments can be combined in any way as long as there is no structural conflict. The present application is not intended to be limited to the particular embodiments disclosed herein but is to cover all embodiments that may fall within the scope of the appended claims.

Claims

1. A tab flattening device (400), comprising:

a clamp (30), the clamp (30) for clamping the electrode assembly (23) in a radial direction;

a sleeve assembly (50) comprising:

a furling part (502), wherein the furling part (502) is used for moving along a first direction to furl the electrode lug (201) of the electrode component (23) to a direction close to the electrode component (23), and the first direction is parallel to an axis (231) of the electrode component (23) and faces to the clamp (30);

the limiting part (501), the limiting part (501) is connected with a first end of the furling part (502), the first end faces the clamp (30), and the limiting part (501) is used for surrounding the electrode assembly (23) when the furling part (502) moves along the first direction and is abutted to the clamp (30) after the tab (201) is furled;

the electrode assembly comprises a pushing portion (503), wherein the pushing portion (503) is arranged at the second end of the folding portion (502), the second end is far away from the clamp (30), the pushing portion (503) is used for folding the electrode lug (201) and then extruding the electrode lug (201) in the first direction, so that the electrode lug (201) is rubbed flat to a preset ear height, and the ear height refers to the height of the electrode lug along the end face (23 a) of the non-electrode ear area, axially protruding out of the electrode assembly (23).

2. The tab flattening device (400) according to claim 1, characterized in that the folded part (502) and the stopper part (501) are cylindrical, the diameter of the folded part (502) is gradually reduced from the first end to the second end, and the diameter of the stopper part (501) is the same as the diameter of the folded part (502) at the first end.

3. The tab flattening device (400) according to claim 2, wherein the tapered portion (502) is a curved tubular shape.

4. The tab flattening device (400) according to any one of claims 2 to 3, characterized in that the diameter of the stopper portion (501) is 3mm to 5mm larger than the diameter of the gathered portion (502) at the second end.

5. The tab flattening apparatus (400) according to any one of claims 1 to 4, wherein the pushing section (503) includes a pushing face (5031), a pushing rod (5032), and a pushing barrel (5033); wherein the content of the first and second substances,

said pusher barrel (5033) is connected to said second end of said collet (502), said pusher barrel (5033) having the same diameter as said collet (502) at said second end;

the push rod (5032) is connected with the push surface (5031) and used for pushing the push surface (5031) to move in the first direction in the push barrel (5033) so as to press the tab (201).

6. The tab flattening device (400) according to any one of claims 1 to 5, characterized in that a first surface of the clamp (30) is provided with a slip prevention structure (301), the slip prevention structure (301) being used to increase a frictional force between the electrode assembly (23) and the clamp (30) in the first direction, wherein the first surface is a surface of the clamp (30) that contacts the electrode assembly (23).

7. The tab flattening apparatus (400) according to claim 6, characterized in that the anti-slip structure (301) is rubber particles.

8. The tab flattening device (400) according to any one of claims 1 to 7, characterized in that the jig (30) has an abutment surface perpendicular to the first direction for abutting against the stopper portion (501).

9. The tab flattening device (400) according to any one of claims 1 to 8, characterized in that, in the first direction, the sum of the lengths of the stopper portion (501) and the gather portion (502) is less than half of the difference between the length of the electrode assembly (23) before flattening and the length of the jig (30).