Flattening device and battery assembly system

Abstract

The invention provides a smoothing device and a battery assembly system, and solves the problem of wrinkling of an insulating protective film outside an electrode assembly in the prior art. The smoothing device comprises a rack, a driving mechanism and a pair of matched rollers. The roller is rotationally connected with the rack and is used for flattening a to-be-flattened piece; the driving mechanism is arranged on the rack, connected with the rollers and used for driving the pair of rollers to rotate synchronously. In this way, the driving mechanism drives the pair of rollers to rotate synchronously, the linear speeds of the outer surfaces of the two rollers are the same, and therefore the problem that in the related technology, two driving sources are adopted to drive the pair of rollers to be different in rotating speed is solved.

Description

Technical Field

[0001] This application relates to the technical field of batteries, and particularly to a flattening device and a battery assembly system. Background Art

[0002] A battery includes a housing and an electrode assembly, and the electrode assembly is installed inside the housing. Since the electrode assembly is wrapped with an insulating protective film, if the insulating protective film is wrinkled, the wrinkled insulating protective film will expose the electrode assembly; the exposed part of the electrode assembly contacts the housing, which may cause safety accidents such as short circuits and explosions of the battery. Summary of the Invention

[0003] The main technical problem to be solved by this application is to provide a flattening device and a battery assembly system to solve the problem that the insulating protective film outside the electrode assembly is wrinkled in the prior art.

[0004] To solve the above technical problem, the first technical solution adopted by this application is: to provide a flattening device, which includes a frame, a driving mechanism, and a pair of cooperating rollers. The rollers are rotatably connected to the frame and are used for flattening the workpiece to be flattened; the driving mechanism is arranged on the frame and is connected to the rollers for driving the pair of rollers to rotate synchronously. In this way, the driving mechanism drives the pair of rollers to rotate synchronously, so that the linear speeds of the outer surfaces of the two rollers are the same, thus solving the problem in the related art that two driving sources are used to drive a pair of rollers at different speeds respectively.

[0005] In some embodiments, the driving mechanism includes a rack and a pair of gears; the gears are coaxially arranged with the rollers, and both pairs of gears are engaged with the rack; the rack extends in the first direction and can move relative to the frame in the first direction; wherein, during the process of the rack moving in the first direction, at least part of the rack drives the pair of gears to rotate synchronously. In this way, since the gears are coaxially arranged with the rollers, during the process of the rack moving in the first direction, at least part of the rack drives the pair of gears to rotate synchronously; so that the rotational speeds (i.e., angular velocities) of the rollers and the gears are the same, and thus the rotational speeds of the two rollers (i.e., the linear speeds of the outer surfaces of the rollers) are the same.

[0006] In some embodiments, the flattening device further includes: elastic members and a pair of sliding members; the sliding members are slidably connected to the frame, and the sliding members slide relative to the frame in the second direction; the rollers are rotatably connected to the sliding members; the elastic members are configured to drive the pair of sliding members to approach or move away from each other in the second direction; the second direction is perpendicular to the first direction and perpendicular to the axial direction of the rollers. Wherein, as the rack moves in the first direction, the distance between the pair of rollers in the second direction first gradually decreases to a preset distance and then gradually increases.

[0007] In this way, as the rack moves along the first direction, a pair of sliding members are driven by an elastic member to approach or move away from each other along the second direction, so that a pair of rollers approach or move away from each other along the second direction, and also keep a pair of gears meshed with the rack all the time. Since as the rack moves along the first direction, the distance between the pair of rollers along the second direction first gradually decreases to a preset distance and then gradually increases. When the distance between the two rollers gradually decreases, the two rollers gradually approach the electrode assembly. When the distance between the two rollers is a preset distance, the two rollers clamp the electrode assembly, so that the two rollers smooth the electrode assembly; and the linear velocity of the outer surfaces of the two rollers is the same as the velocity of the shell inserting device pushing the electrode assembly, so that the electrode assembly can be placed in the shell, reducing the occurrence of wrinkles on the insulating protective film outside the electrode assembly. When the distance between the two rollers gradually increases, the two rollers gradually separate from the electrode assembly.

[0008] In some embodiments, along the second direction, the rack has two opposite tooth surfaces, and a pair of gears are respectively meshed on the two tooth surfaces of the rack. Among them, one of the two tooth surfaces is a concave tooth surface, and the other tooth surface is parallel to the first direction; or, both of the two tooth surfaces are concave tooth surfaces. In this way, one rack can drive two gears to rotate, simplifying the structure.

[0009] In some embodiments, the concave tooth surface includes a first section of tooth surface, a second section of tooth surface and a third section of tooth surface connected in sequence; the second section of tooth surface is parallel to the first direction; along the first direction, the sizes of multiple tooth structures of the first section of tooth surface gradually decrease first, and the sizes of multiple tooth structures of the third section of tooth surface gradually increase first; wherein, the tooth structure size is the size between a tooth structure and the center line of the rack along the second direction; the center line extends along the first direction.

[0010] In this way, the first section of tooth surface, the second section of tooth surface and the third section of tooth surface are all straight tooth surfaces, and the first section of tooth surface and the third section of tooth surface are obliquely connected to both ends of the second section of tooth surface, so that when the gear meshes with the concave tooth surface, the distance between the gear and the center line gradually decreases to be unchanged and then increases. In addition, the straight tooth surface is easy to prepare or has a lower price.

[0011] In some embodiments, the included angle between the first section of tooth surface and the second section of tooth surface is 120° - 150°; and / or, the included angle between the third section of tooth surface and the second section of tooth surface is 120° - 150°.

[0012] In this way, when the included angle is less than 120°, the size of the first section of tooth surface along the first direction is smaller, and when the rack moves a little, the gear meshes with the second section of tooth surface, so that the rotational speed of the gear meshed with the first section of tooth surface is larger. When the included angle is less than 150°, the size of the first section of tooth surface along the first direction is larger, making the mass of the rack heavier. The included angle effect of the third section of tooth surface can refer to the included angle effect of the first section of tooth surface.

[0013] In some embodiments, the rack is symmetrically arranged along the axis of symmetry parallel to the first direction and symmetrically arranged along the axis of symmetry parallel to the second direction. In this way, the structure of the rack is relatively simple and convenient for manufacturing.

[0014] In some embodiments, the elastic member includes two compression elastic members. The compression elastic members are connected between the frame and the sliding member, and the compression elastic members are located on the side where the two rollers are away from each other; alternatively, the elastic member includes a tension elastic member, and the tension elastic member is connected between a pair of sliding members. In this way, when the rack moves in the first direction, the two gears mesh with the rack, and under the action of the thrust generated by the two compression elastic members and / or the tensile force generated by the tension elastic member, the pair of rollers move closer to or away from each other.

[0015] In some embodiments, the rack includes a first rack and a second rack arranged along the second direction; a pair of gears are located between the first rack and the second rack and respectively mesh with the tooth surfaces of the first rack and the second rack; wherein, the tooth surface of the first rack is a convex tooth surface, and the tooth surface of the second rack is parallel to the first direction; alternatively, the tooth surfaces of the first rack and the second rack are both convex tooth surfaces.

[0016] In this way, by the first rack and the second rack respectively meshing with the two gears, when the first rack and the second rack move synchronously in the first direction, the first rack and the second rack drive the two gears to rotate. Without changing the total weight of the first rack and the second rack, by changing the installation positions of the first rack and the second rack, the distance between the two rollers can be changed; it is convenient for the pair of rollers to clamp electrode assemblies of different sizes, etc.

[0017] In some embodiments, the flattening device further includes a slide rail, the slide rail is arranged on the frame, and the sliding member is slidably arranged on the slide rail; alternatively, the frame has a chute, and the sliding member is slidably arranged on the chute. In this way, the provided slide rail and / or chute can enable the sliding member to slide relative to the frame.

[0018] In some embodiments, the sliding member has a mounting hole, and the roller is rotatably arranged in the mounting hole. In this way, the rotational connection between the sliding member and the roller can be realized without other components.

[0019] To solve the above technical problems, the second technical solution provided by this application is: to provide a battery assembly system, which includes a conveying device, an assembly device, and the above-mentioned flattening device; the conveying device is used to convey the structures to be assembled to each station of the assembly device; the stations of the assembly device include a casing device; the casing device is used to load the electrode assembly into the casing from the open end of the casing; when the electrode assembly is loaded into the casing, a pair of rollers of the flattening device are used to clamp and flatten the electrode assembly passing through the pair of rollers. Since the battery assembly system includes the above-mentioned flattening device, therefore, this battery assembly system has the effects of the above-mentioned flattening device, which will not be elaborated here. Brief Description of the Drawings

[0020] To more clearly illustrate the technical solutions in the embodiments of this application, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the drawings in the following description are only some embodiments of this application. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0021] Figure 1 It is the front view of a flattening device provided by this application;

[0022] Figure 2 It is the top view of a flattening device provided by this application;

[0023] Figure 3 It is the schematic structural diagram of a rack and a pair of gears meshing provided by this application;

[0024] Figure 4 It is the front view of another flattening device provided by this application;

[0025] Figure 5 It is the top view of another flattening device provided by this application;

[0026] Figure 6 It is the top view of yet another flattening device provided by this application;

[0027] Figure 7 It is the schematic structural diagram of another rack and a pair of gears meshing provided by this application;

[0028] Figure 8 It is the top view of still another flattening device provided by this application;

[0029] Figure 9 It is the schematic structural diagram of the first rack and the second rack meshing with a pair of gears provided by this application;

[0030] Figure 10 It is the front view of the battery assembly system provided by this application;

[0031] Figure 11 It is a top view of the battery assembly system provided by this application.

[0032] In the figure: 1. Smoothing device; 11. Frame; 12. Driving mechanism; 122. Rack; 1221. First rack; 1222. Second rack; 123. First tooth surface; 124. Second tooth surface; 125. Third tooth surface; 121. Gear; 132. Rotating shaft; 133. Roller; 14. Slide rail; 15. Elastic member; 16. Sliding member; 17. Driving member; 2. Housing; 3. Electrode assembly; 4. Conveying equipment; 5. Assembly equipment; 51. Housing inserting device. Specific embodiments

[0033] Next, in combination with the accompanying drawings of the specification, the solutions of the embodiments of this application will be described in detail.

[0034] In the following description, for the purpose of illustration rather than limitation, specific details such as specific system structures, interfaces, and technologies are presented in order to thoroughly understand this application.

[0035] Next, in combination with the accompanying drawings in the embodiments of this application, the technical solutions in the embodiments of this application will be clearly and completely described. Obviously, the described embodiments are only a part of the embodiments of this application, rather than all the embodiments. Based on the embodiments in this application, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the scope of protection of this application.

[0036] The terms "first", "second", and "third" in this application are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first", "second", and "third" may explicitly or implicitly include at least one of such features. In the description of this application, the meaning of "a plurality" is at least two, such as two, three, etc., unless otherwise specifically and clearly defined. All directional indications (such as up, down, left, right, front, back...) in the embodiments of this application are only used to explain the relative positional relationship and movement conditions between components in a specific posture (as shown in the accompanying drawings). If this specific posture changes, then the directional indications will also change accordingly. In addition, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or device that includes a series of steps or units is not limited to the listed steps or units, but optionally further includes steps or units not listed, or optionally further includes other steps or units inherent to these processes, methods, products, or devices.

[0037] References herein to "embodiments" mean that the particular features, structures, or characteristics described in connection with the embodiments can be included in at least one embodiment of the present application. The phrase appears in various places in the specification and does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0038] In the related art, a battery includes a housing and an electrode assembly (which can also be referred to as an electrode core), and an insulating protective film is wrapped outside the electrode assembly; an insertion device and a flattening device are used to install the electrode assembly in the housing; this can reduce the occurrence of wrinkles in the insulating protective film outside the electrode assembly. The insertion device can refer to the insertion device introduced in the following text.

[0039] Existing flattening devices include two roller mechanisms, each roller mechanism includes a driving source and a roller, and the driving source drives the roller to rotate. By using the cooperation of the two rollers, the electrode assembly can be flattened and then installed in the housing. However, when control failures occur in the driving sources of the two roller mechanisms (for example, there are differences in the currents received by the two driving motors), the rotational speeds of the rollers driven by the two driving sources will be different; the two rollers with different rotational speeds will cause the insulating protective film of the electrode assembly located between the two rollers to wrinkle, thereby exposing the electrode assembly; the exposed part of the electrode assembly contacts the housing, which may cause safety accidents such as short circuits and explosions of the battery.

[0040] An embodiment of the present application provides a flattening device, which can be used during the process of installing an electrode assembly in a housing. By using this flattening device, the electrode assembly can be flattened and then installed in the housing. Thereby, the problem of wrinkles in the insulating protective film wrapped outside the electrode assembly is solved, so that the insulating protective film does not expose the electrode assembly, and the accidents of the battery are reduced.

[0041] Of course, this flattening device can also be used in other fields. For example, the flattening device can be used to transport lithium strips, electrode sheets, etc. Exemplarily, a lithium strip is located between the two rollers of the flattening device, and when the two rollers rotate, the lithium strip is transported out. Another example is that the flattening device can be used to extend a sheet. Exemplarily, the sheet is placed between the two rollers, and through the extrusion of the two rotating rollers, the length or width of the sheet is extended and the thickness is reduced. The material of the sheet can be a metal, and the metal can be a single metal (such as lithium, iron, aluminum, copper, silver, etc.), and the metal can also be an alloy of the above single metals (such as aluminum alloy, lithium alloy, iron alloy, silver alloy, copper alloy, etc.). In the following text, the flattening device is used to flatten the electrode assembly as an example for illustration.

[0042] See Figure 1 and Figure 2, the flattening device 1 may include a frame 11, a pair of cooperating rollers 133, and a driving mechanism 12; the rollers 133 are rotatably connected to the frame 11 and are used for flattening the workpiece to be flattened; the driving mechanism 12 is arranged on the frame 11 and is connected to the rollers 133 for driving the pair of rollers 133 to rotate synchronously. In this way, the driving mechanism 12 drives the pair of rollers 133 to rotate synchronously, so that the linear speeds of the outer surfaces of the two rollers 133 are the same, thus solving the problem in the related art that two driving sources are used to drive a pair of rollers at different speeds respectively.

[0043] During the process of the housing device 51 installing the electrode assembly into the housing, the electrode assembly passes between the two rollers 133. By using the same speed of the two rollers 133, the electrode assembly can be flattened, so that the electrode assembly is directly opposite to the opening end of the housing (that is, the gap between the two rollers 133 is directly opposite to the opening end of the housing), and the electrode assembly can directly enter the housing; thus solving the problem that during the process of the electrode assembly entering the housing, the electrode assembly rubs against the housing, resulting in wrinkles in the insulating protective film.

[0044] In some embodiments, the driving mechanism 12 may include a driving wheel and a pair of driven wheels, and the driven wheels are coaxially arranged with the rollers 133; the driving wheel drives the pair of driven wheels to rotate synchronously through a belt or a chain, so as to make the pair of rollers 133 rotate synchronously. In some examples, the driving mechanism 12 may include a driving member. The driving member is installed on the frame 11, and the driving member is connected to the driving wheel for driving the driving wheel to rotate. For example, the driving member can drive an electric motor.

[0045] In some embodiments, the driving mechanism 12 may include a driving gear and a pair of driven gears, and the driven gears are coaxially arranged with the rollers 133; the driving gear meshes with the pair of driven gears, and when the driving gear rotates, the driving gear drives the pair of driven gears to rotate synchronously, so as to make the pair of rollers 133 rotate synchronously. In some examples, the driving mechanism 12 may include a driving member. The driving member is installed on the frame 11. The driving member is connected to the driving gear for driving the driving gear to rotate. For example, the driving member can drive an electric motor.

[0046] In some embodiments, the driving mechanism 12 may include a rack 122 and a pair of gears 121; the gears 121 are coaxially arranged with the drum 133, and both of the pair of gears 121 are engaged with the rack 122; the rack 122 extends along the first direction X and is capable of moving relative to the frame 11 along the first direction X; during the process of the rack 122 moving along the first direction X, at least a part of the rack 122 drives the pair of gears 121 to rotate synchronously. In some examples, the driving mechanism 12 may include a driving member 17. The driving member 17 may be mounted on the frame. The driving member 17 is connected to the rack 122 and is used to drive the rack 122 to move along the first direction X. For example, the driving member 17 may be a mechanism capable of telescoping along the first direction X (which may be referred to as a telescoping mechanism), and the telescoping mechanism drives the rack 122 to move along the first direction X. The telescoping mechanism may be a hydraulic telescoping mechanism, a pneumatic telescoping mechanism, an electric push rod, etc.

[0047] In this way, since the gears 121 and the drum 133 are coaxially arranged, during the process of the rack 122 moving along the first direction X, at least a part of the rack 122 drives the pair of gears 121 to rotate synchronously; such that the rotational speeds (i.e., angular velocities) of the drums 133 and the gears 121 are the same, and thus the rotational speeds of the two drums 133 (i.e., the linear velocities of the outer surfaces of the drums 133) are the same.

[0048] An embodiment of the present application provides a comparative solution, which may include a pair of cooperating belt drum mechanisms. The belt drum mechanism may include a mounting bracket, a cylinder, a drum, a belt, and a driving motor; the cylinder, the belt, and the driving motor are all arranged on the mounting bracket, and the driving motor drives the drum to rotate through the belt. The drum is slidably arranged on the mounting bracket; the cylinder is connected to the drum and is used to push the drum to slide; so that the drums of the pair of belt drum mechanisms approach or separate from each other. When the drums of the pair of belt drum mechanisms approach each other, the drums of the pair of belt drum mechanisms clamp the electrode assembly and flatten the electrode assembly. When the drums of the pair of belt drum mechanisms separate from each other, the drums of the pair of belt drum mechanisms separate from the electrode assembly. In this way, the electrode assembly is moved between the drums in the pair of belt drum mechanisms by using the casing device and is pushed into the shell. During the process of using the casing device to push the electrode assembly into the shell, first control the cylinder so that the drums in the pair of belt drum mechanisms approach each other and clamp the electrode assembly, so that the electrode assembly is flattened. Then, as the casing device pushes, the electrode assembly enters the open end of the shell. Finally, control the cylinder to make the drums in the pair of belt drum mechanisms separate from each other, so that the drums in the pair of belt drum mechanisms separate from the electrode assembly.

[0049] However, in each belt roller mechanism, the driving motor drives the roller to rotate through the belt. When there are control failures in the driving motors of a pair of belt roller mechanisms (such as differences in the current received by the two driving motors), the rotational speeds of the two driving motors will be different, resulting in different rotational speeds of the two rollers; the two rollers with different rotational speeds will cause the insulating protective film of the electrode assembly located between the two rollers to wrinkle.

[0050] Compared with the belt roller mechanism in the comparative scheme, the embodiment of the present application uses a power source (such as the above-mentioned driving member 17). The driving member 17 drives the rack 122 to move along the first direction X, so that the speeds of the two gears 121 meshing with the rack 122 are the same, thereby making the rotational speeds of the two rollers 133 the same. It solves the situation where the rotational speeds of the two rollers 133 are different due to problems with the power source; it also saves costs. Furthermore, it increases stability, reduces the failure rate, and increases the excellent product rate.

[0051] The rack 122 extends along the first direction X. That is to say, the length direction of the rack 122 is parallel to the first direction X. In some examples, the arrangement of the multiple tooth structures (which can also be called teeth) of the rack 122 can be the arrangement of the multiple tooth structures on a straight rack. In other examples, the arrangement of the multiple tooth structures of the rack 122 can be the arrangement of the multiple tooth structures on an inclined rack.

[0052] The rack 122 can move relative to the frame 11 along the first direction X; that is to say, the frame 11 is fixed, and the rack 122 can move along the first direction X.

[0053] The gear 121 is coaxially arranged with the roller 133. In some examples, the gear 121 is contact-fitted on the roller 133. In other examples, the gear 121 and the roller 133 are connected by a connecting member; for example, the connecting member is a rotating shaft 132. Both the roller 133 and the gear 121 are sleeved on the rotating shaft 132, and the rotating shaft 132 can be rotatably arranged on the frame 11. A pair of cooperating rollers can be understood as having the axis directions of a pair of rollers 133 parallel and intersecting (such as perpendicular) to the first direction X.

[0054] A pair of gears 121 are both meshed with the rack 122. That is to say, one gear 121 is meshed with the rack 122, and the other gear 121 is also meshed with the rack 122. In some examples, the ratio of the number of racks 122 to the number of gears 121 is 1:2. For example, the number of racks 122 can be one, and the number of gears 121 can be two. Another example is that the number of racks 122 can be two, and the number of gears 121 can be four. In this way, the rack 122 - gear 121 - rack 122 can drive a pair of rollers to rotate more stably.

[0055] The drum 133 is rotatably connected to the frame 11, which can be understood as both ends of the drum 133 being rotatably connected to the frame 11. For example, the frame 11 has a first through hole, and the drum 133 is rotatably arranged in the first through hole. Another example is that the drum 133 is rotatably arranged with the sliding member 16, and the sliding member 16 is slidably connected to the frame 11. The frame 11 may include two mounting plates opposite to each other in the second direction Y, and the mounting plates can be mounted on the preset workstations described below. For example, the mounting plate has a first through hole. Another example is that the sliding member 16 is slidably connected to the mounting plate. The frame 11 may further include a connecting plate, and the connecting plate connects the two mountings into an integral structure. The position of the rack 122 relative to the frame 11 is not limited. For example, the rack 122 may be located inside the frame 11. Another example is that the rack 122 may be located outside the frame 11.

[0056] At least part of the rack 122 drives a pair of gears 121 to rotate synchronously. It can be understood that when at least part of the pair of gears 121 meshes with the rack 122, the pair of gears 121 rotate simultaneously and at the same speed, so that the surface linear speeds of the pair of drums 133 are the same; and they also stop simultaneously.

[0057] Exemplarily, referring to Figures 1 to 3 , when the tooth surface of the rack 122 is parallel to the first direction X, the rack 122 can be called a straight rack; for example, the straight rack may have two opposite tooth surfaces; another example is that the rack 122 may further include a first rack and a second rack, and the tooth surfaces of the first rack and the second rack are opposite to each other. Among them, the two tooth surfaces of this straight rack are different from the tooth surfaces of the rack 122 with two opposite tooth surfaces described below, and the others are the same (such as the installation position, connection relationship); similarly, the straight rack including the first rack and the second rack is different from the rack 122 including the first rack 1221 and the second rack 1222 in terms of tooth surfaces, and the others are the same (such as the installation position, connection relationship); details are not repeated.

[0058] When the rack 122 is a straight rack, during the process of the rack 122 moving along the first direction X, all parts of the rack 122 drive a pair of gears 121 to rotate synchronously. At this time, the drum 133 is rotatably connected to the frame 11, and the drum 133 is not slidably connected to the frame 11; so that the distance between the two drums 133 remains unchanged. The frame 11 is provided with a first through hole; for example, the drum 133 is located in the first through hole, and the drum 133 is in clearance fit with the first through hole; another example is that the drum 133 is arranged in the first through hole through a bearing. In a possible implementation manner, the rotating shaft 132 is arranged in the first through hole through a bearing.

[0059] In this way, when the rack 122 is a straight rack, the distance between the two drums 133 is adjusted to be the same as the width or length of the electrode assembly, and the two drums 133 can be used to smooth the electrode assembly.

[0060] Exemplarily, referring to Figure 1 and Figure 5 , during the process of the rack 122 moving along the first direction X, a part of the rack 122 drives a pair of gears 121 to rotate synchronously; the part of the rack 122 can be understood as a straight rack. When the rack 122 is not a straight rack, since a pair of gears 121 mesh with the rack 122, the distance between the pair of gears 121 changes, that is, the distance between a pair of rollers 133 along the second direction Y changes. At this time, the rack 122 will be introduced in detail below and will not be elaborated here.

[0061] In some embodiments, referring to Figure 1 、 Figures 5 to 9 , the flattening device 1 further includes: an elastic member 15 and a pair of sliding members 16; the sliding members 16 are slidably connected to the frame 11, and the sliding members 16 slide relative to the frame 11 along the second direction Y; the rollers 133 are rotatably connected to the sliding members 16; the elastic member 15 is configured to drive the pair of sliding members to approach or separate from each other along the second direction Y; the second direction Y is perpendicular to the first direction X and perpendicular to the axial direction of the rollers 133. Among them, as the rack 122 moves along the first direction X, the distance between the pair of rollers 133 along the second direction Y first gradually decreases to a preset distance and then gradually increases.

[0062] In this way, as the rack 122 moves along the first direction X, the elastic member 15 drives the pair of sliding members to approach or separate from each other along the second direction Y, so that the pair of rollers 133 approach or separate from each other along the second direction Y, and also makes the pair of gears 121 and the rack 122 always mesh. Since as the rack 122 moves along the first direction X, the distance between the pair of rollers 133 along the second direction Y first gradually decreases to a preset distance and then gradually increases. When the distance between the two rollers 133 gradually decreases, the two rollers 133 gradually approach the electrode assembly. When the distance between the two rollers 133 is a preset distance, the two rollers 133 clamp the electrode assembly, so that the two rollers 133 flatten the electrode assembly; and the linear velocity of the outer surfaces of the two rollers 133 is the same as the speed at which the casing device pushes the electrode assembly, so that the electrode assembly can be placed in the casing, reducing the occurrence of wrinkles in the insulating protective film outside the electrode assembly. When the distance between the two rollers 133 gradually increases, the two rollers 133 gradually separate from the electrode assembly.

[0063] In this embodiment, the meshing of the rack 122 and the pair of gears 121 replaces the driving motor, belt and cylinder in the pair of belt roller mechanisms in the related art. That is, the meshing of the rack 122 and the pair of gears 121 in this embodiment can achieve the functions of the driving motor, belt and cylinder in the related art, and also simplifies the structure, thereby reducing the cost.

[0064] A preset distance can be understood. The rack 122 drives a pair of rollers 133 to rotate within a preset time, and within this preset time, the distance between the pair of rollers 133 in the second direction Y remains unchanged, and the pair of rollers 133 rotate synchronously. That is, a preset distance corresponds to the situation when the gear 121 meshes with the second tooth surface in the following text. The preset time is the time for inserting the electrode assembly into the housing; for example, the time for smoothing the electrode assembly.

[0065] The elastic member 15 can be a type of structure that can generate an elastic force; the elastic member 15 can be a spring and / or a spring piece, etc. The elastic force of the elastic member 15 is used to drive the pair of rollers 133 to approach or move away from each other in the second direction Y. In some examples, the direction of the elastic force generated by the elastic member 15 is the second direction Y. In other examples, the elastic force generated by the elastic member 15 forms an angle with the second direction Y, and this elastic force has a component force in the second direction Y, and this component force can drive the pair of rollers 133 to approach or move away from each other in the second direction.

[0066] The pair of sliding members 16 approach or move away from each other in the second direction Y. It can be understood that one sliding member 16 does not move and the other sliding member 16 moves; it can also be understood that both sliding members 16 can move. The pair of rollers 133 approach or move away from each other in the second direction Y. It can be understood that one roller 133 does not move and the other roller 133 moves; it can also be understood that both rollers 133 can move.

[0067] The sliding member 16 is slidably connected to the frame 11. It can be understood that one sliding member 16 (which can be called the first sliding member) is slidably connected to the frame 11, and the other sliding member 16 (which can be called the second sliding member) is slidably connected to the frame 11. The roller 133 is rotatably connected to the sliding member 16. It can be understood that one roller 133 (which can be called the first roller) is rotatably connected to the first sliding member; the other roller 133 (which can be called the second roller) is rotatably connected to the second sliding member.

[0068] Among them, the number of the first sliding members can be at least two (such as two, or three, etc.). The number of the second sliding members can be at least two (such as two, or three, etc.). For example, the number of the first sliding members is the same as the number of the second sliding connections, or both are two.

[0069] In other embodiments, as the rack 122 moves along the first direction X, the distance between the pair of rollers 133 in the second direction Y first gradually decreases to a preset distance. In other embodiments, as the rack 122 moves along the first direction X, the distance between the pair of rollers 133 in the second direction Y is a preset distance and then gradually increases.

[0070] In some embodiments, refer to Figure 1 、Figures 5 to 7 Along the second direction Y, the rack 122 has two opposite tooth surfaces (at this time, the rack 122 can be called a double-sided rack 122 or double-sided teeth), and a pair of gears 121 are respectively meshed on the two tooth surfaces of the rack 122; wherein, one of the two tooth surfaces is a concave tooth surface, and the other tooth surface is parallel to the first direction X; or, both tooth surfaces are concave tooth surfaces. In this way, two gears 121 can be driven to rotate by one rack 122, which simplifies the structure.

[0071] For the concave tooth surface, it can be understood that the first part of the tooth surface (i.e., the second section of the tooth surface 124 hereinafter) is parallel to the first direction X; the second part and the third part of the tooth surface are located on the side of the first part of the tooth surface away from the opposite tooth surface, and the second part of the tooth surface has a first included angle with the first part of the tooth surface; the first included angle is greater than 90° and less than 180° (such as 91°, 95°, 100°, 110°, 120°, 130°, 140°, 150°, 160°, 170°, 179°, etc.); the third part of the tooth surface has a second included angle with the first part of the tooth surface; the second included angle is greater than 90° and less than 180° (such as 91°, 95°, 100°, 110°, 120°, 130°, 140°, 150°, 160°, 170°, 179°, etc.). In some examples, the second part of the tooth surface can be a curved (such as a minor arc) tooth surface, and at this time, the first included angle can be understood as the included angle between the tangent of the curved tooth surface and the first part of the tooth surface. In other examples, the second part of the tooth surface can be a straight tooth surface. The number of the second part of the tooth surface can be one section of the tooth surface, and at this time, the second part of the tooth surface can be called the first section of the tooth surface 123 hereinafter. The number of the second part of the tooth surface can also be multiple sections of tooth surfaces connected in sequence; for example, the included angles between the extension lines of the multiple sections of tooth surfaces and the first part of the tooth surface increase in sequence, or decrease in sequence, or increase first and then decrease, etc.

[0072] Among them, the shape of the third part of the tooth surface can refer to the relevant description of the shape of the second part of the tooth surface. The number of the third part of the tooth surface can refer to the relevant description of the number of the second part of the tooth surface. When the number of the third part of the tooth surface is one section of the tooth surface, at this time, the third part of the tooth surface can be called the third end tooth surface hereinafter.

[0073] Exemplarily, one of the two tooth surfaces is a concave tooth surface, and the other tooth surface is parallel to the first direction X. At this time, the gear 121 meshed with one tooth surface rotates relative to the frame 11 and also slides; the gear 121 meshed with the other tooth surface rotates relative to the frame 11 and does not slide along the second direction Y. That is, the elastic member 15 drives the gear 121 meshed with this one tooth surface to move, and drives the gear 121 meshed with the other tooth surface not to move.

[0074] Exemplarily, both tooth surfaces are concave tooth surfaces. At this time, the two gears 121 with the two tooth surfaces meshing rotate relative to the frame 11, and also slide relative to the frame 11 along with the sliding member 16. That is, the elastic member 15 drives both of the two gears 121 with the two tooth surfaces meshing to move.

[0075] In some embodiments, the concave tooth surface includes a first tooth surface 123, a second tooth surface 124, and a third tooth surface 125 connected in sequence; the second tooth surface 124 is parallel to the first direction X; along the first direction X, the tooth structure dimensions of the first tooth surface 123 gradually decrease first, and the tooth structure dimensions of the third tooth surface 125 gradually increase first; wherein, the tooth structure dimension is the dimension between a tooth structure and the center line of the rack 122 in the second direction Y; the center line extends along the first direction X.

[0076] In this way, the first tooth surface 123, the second tooth surface 124, and the third tooth surface 125 are all straight tooth surfaces, and the first tooth surface 123 and the third tooth surface 125 are obliquely connected to both ends of the second tooth surface 124, so that when the gear 121 meshes with the concave tooth surface, the distance between the gear 121 and the center line gradually decreases to be unchanged and then increases. In addition, the straight tooth surface is easy to prepare or has a lower price. At this time, the first tooth surface 123, the second tooth surface 124, and the third tooth surface 125 can form a shape as Figure 7 shown.

[0077] In some embodiments, the included angle (i.e., the first included angle) between the first tooth surface 123 and the second tooth surface 124 is 120° to 150° (such as 120°, 125°, 130°, 135°, 140°, 145°, 150°, etc.); and / or, the included angle (i.e., the second included angle) between the third tooth surface 125 and the second tooth surface 124 is 120° to 150° (such as 120°, 125°, 130°, 135°, 140°, 145°, 150°, etc.).

[0078] In this way, when the included angle is less than 120°, the dimension of the first tooth surface 123 along the first direction X is smaller. When the rack 122 moves a little, the gear 121 meshes with the second tooth surface 124, so that the rotation speed of the gear 121 meshing with the first tooth surface 123 is larger. When the included angle is less than 150°, the dimension of the first tooth surface 123 along the first direction X is larger, making the mass of the rack 122 heavier. The included angle effect of the third tooth surface 125 can refer to the included angle effect of the first tooth surface 123.

[0079] In some embodiments, the rack 122 is symmetrically arranged along the symmetry axis parallel to the first direction X and symmetrically arranged along the symmetry axis parallel to the second direction Y. In this way, the structure of the rack 122 is relatively simple and convenient for manufacturing.

[0080] In some embodiments, referring to Figure 6 , the elastic member 15 includes two compression elastic members, and the compression elastic members are connected between the frame 11 and the sliding member 16; and the compression elastic members are located on the side where the two rollers 133 are away from each other. Or, referring to Figure 5 , the elastic member 15 includes a tension elastic member, and the tension elastic member is connected between a pair of sliding members 16.

[0081] In this way, when the rack 122 moves in the first direction X, the two gears 121 mesh with the rack 122, and under the action of the thrust generated by the two compression elastic members and / or the tensile force generated by the tension elastic member, the pair of rollers 133 approach or move away from each other.

[0082] Exemplarily, the elastic member 15 includes two compression elastic members, and the compression elastic members are connected between the frame 11 and the sliding member 16; and the compression elastic members are located on the side where the two rollers 133 are away from each other. Again exemplarily, the elastic member 15 includes a tension elastic member, and the tension elastic member is connected between a pair of sliding members 16. Again exemplarily, the elastic member 15 includes two compression elastic members, and the compression elastic members are connected between the frame 11 and the sliding member 16; and the compression elastic members are located on the side where the two rollers 133 are away from each other. The elastic member 15 includes a tension elastic member, and the tension elastic member is connected between a pair of sliding members 16.

[0083] The elastic member 15 and the frame 11 can be fixedly connected. For example, the fixed connection can be welding, gluing, etc.; it can also be a detachable connection. For example, the elastic member 15 is hung on a hook of the frame 11. The elastic member 15 and the sliding member 16 can be fixedly connected. For example, the fixed connection can be welding, gluing, etc.; it can also be a detachable connection. For example, the elastic member 15 is hung on a hook of the sliding member 16.

[0084] The compression elastic members are located on the side where the two rollers 133 are away from each other; it can be understood that one compression elastic member is located on the side where the first roller is away from the second roller; the other compression elastic member is located on the side where the second roller is away from the first roller.

[0085] The elastic member 15 includes two compression elastic members, and the compression elastic members are connected between the frame 11 and the sliding member 16. It can be understood that one compression elastic member (which can be called the first compression elastic member) is connected between the frame 11 and the first sliding member; the other compression elastic member (which can be called the second compression elastic member) is connected between the frame 11 and the second sliding member. Among them, the number of the first compression elastic member and the second compression elastic member can both be at least one. For example, the number of the first compression elastic member and the second compression elastic member is equal, and can both be, for example, two.

[0086] The number of the tension elastic members can be at least one, and at least one tension elastic member is connected between a pair of sliding members 16.

[0087] In some embodiments, the elastic member 15 includes two tensile elastic members. The tensile elastic members are connected between the frame 11 and the sliding member 16, and the tensile elastic members are located between a pair of rollers 133. In this way, when the rack 122 moves in the first direction X, the two gears 121 mesh with the rack 122, and under the action of the tensile force generated by the two tensile elastic members, the pair of rollers 133 approach or separate from each other.

[0088] In some embodiments, referring to Figure 1 、 Figure 8 and Figure 9 , the rack 122 includes a first rack 1221 and a second rack 1222 arranged along the second direction Y; a pair of gears 121 are located between the first rack 1221 and the second rack 1222 and mesh with the tooth surfaces of the first rack 1221 and the second rack 1222 respectively; wherein, the tooth surface of the first rack 1221 is a convex tooth surface, and the tooth surface of the second rack 1222 is parallel to the first direction X; or, the tooth surfaces of the first rack 1221 and the second rack 1222 are both convex tooth surfaces.

[0089] In this way, by the first rack 1221 and the second rack 1222 meshing with the two gears 121 respectively, when the first rack 1221 and the second rack 1222 move synchronously in the first direction X, the first rack 1221 and the second rack 1222 drive the two gears 121 to rotate. Without changing the total weight of the first rack 1221 and the second rack 1222, by changing the installation positions of the first rack 1221 and the second rack 1222, the distance between the two rollers 133 is changed; it is convenient for the pair of rollers 133 to clamp electrode assemblies of different sizes, etc.

[0090] Exemplarily, in order to facilitate the synchronous movement of the first rack 1221 and the second rack 1222 in the first direction X; for example, the first rack 1221 and the second rack 1222 are connected into an integral structure through a connecting member; or, the first rack 1221 and the second rack 1222 are installed on the same component (for example, installed on the above-mentioned driving member 17).

[0091] A pair of gears 121 are located between the first rack 1221 and the second rack 1222; it can be understood that the first rack 1221, the pair of gears 121, and the second rack 1222 are arranged in sequence along the second direction Y. For example, the first rack 1221 and the second rack 1222 can be arranged opposite to each other or staggered.

[0092] The convex tooth surface can be understood. The fourth part of the tooth surface is parallel to the first direction X. The fifth and sixth parts of the tooth surface are located between the fourth part of the tooth surface and the opposite side of the tooth surface. There is a third angle between the fifth part of the tooth surface and the fourth part of the tooth surface. The third angle is greater than 90° and less than 180° (such as 91°, 95°, 100°, 110°, 120°, 130°, 140°, 150°, 160°, 170°, 179°, etc.). There is a fourth angle between the sixth part of the tooth surface and the fourth part of the tooth surface. The fourth angle is greater than 90° and less than 180° (such as 91°, 95°, 100°, 110°, 120°, 130°, 140°, 150°, 160°, 170°, 179°, etc.). In some examples, the fifth part of the tooth surface can be a curved (such as an inferior arc) tooth surface. At this time, the third angle can be understood as the angle between the tangent of the curved tooth surface and the fourth part of the tooth surface. In other examples, the fifth part of the tooth surface can be a straight tooth surface. The number of the fifth part of the tooth surface can be one section of the tooth surface. The number of the second part of the tooth surface can be multiple sections of the tooth surface connected in sequence. For example, the angles between the extension lines of the multiple sections of the tooth surface and the fourth part of the tooth surface increase in sequence, or decrease in sequence, or increase first and then decrease, etc.

[0093] Among them, the shape of the sixth part of the tooth surface can refer to the relevant description of the shape of the fifth part of the tooth surface. The number of the sixth part of the tooth surface can refer to the relevant description of the number of the fifth part of the tooth surface.

[0094] Exemplarily, the tooth surface of the first rack 1221 is a convex tooth surface, and the tooth surface of the second rack 1222 is parallel to the first direction X. At this time, the gear 121 meshed with the tooth surface of the first rack 1221 rotates relative to the frame 11 and also slides. The gear 121 meshed with the tooth surface of the second rack 1222 rotates relative to the frame 11 and does not slide along the second direction Y. That is, the elastic member 15 drives the gear 121 meshed with the tooth surface of the first rack 1221 to move, and does not drive the gear 121 meshed with the tooth surface of the second rack 1222 to move.

[0095] Another example is that the tooth surfaces of both the first rack 1221 and the second rack 1222 are convex tooth surfaces. At this time, the two gears 121 meshed with the tooth surfaces of the first rack 1221 and the second rack 1222 rotate relative to the frame 11 and also slide. That is, the elastic member 15 drives both of the two gears 121 meshed with the tooth surfaces of the first rack 1221 and the second rack 1222 to move.

[0096] In the embodiments where the rack 122 includes two opposite tooth surfaces, and in the embodiments where the rack 122 includes a first rack 1221 and a second rack 1222, the distance between the two rollers 133 can be changed. Therefore, the description and explanation of the embodiments where the rack 122 includes a first rack 1221 and a second rack 1222 can refer to the relevant description and explanation of the embodiments where the rack 122 includes two opposite tooth surfaces. For example, the elastic member 15 includes a compression elastic member, and the compression elastic member is connected between a pair of sliding members 16. And / or, the elastic member 15 includes two tension elastic members, the tension elastic members are connected between the frame 11 and the sliding member 16, and the tension elastic members are located on the side where the two rollers 133 are away from each other.

[0097] In some embodiments, referring to Figure 5 and Figure 6 , the flattening device further includes a slide rail 14, the slide rail 14 is arranged on the frame 11, and the sliding member 16 is slidably arranged on the slide rail 14; alternatively, the frame 11 has a chute, and the sliding member 16 is slidably arranged on the chute. In this way, the arranged slide rail 14 and / or chute can enable the sliding member 16 to slide relative to the frame 11.

[0098] Exemplarily, the flattening device further includes a slide rail 14, the slide rail 14 is arranged on the frame 11, and the sliding member 16 is slidably arranged on the slide rail 14. In some examples, the slide rail 14 is arranged on the top of the frame 11. Again exemplarily, the frame 11 has a chute, and the sliding member 16 is slidably arranged on the chute. Again exemplarily, the flattening device further includes a slide rail 14, the slide rail 14 is arranged on the frame 11, and the sliding member 16 is slidably arranged on the chute and the slide rail 14. In some examples, the sliding member slides on the slide rail 14 and the chute simultaneously. For example, the sliding member is located between the slide rail 14 and the chute, so that two opposite parts of the sliding member are respectively slidably connected to the slide rail and the chute. For another example, the slide rail 14 and the chute are arranged side by side, so that the parts on the same side of the sliding member are slidably connected to the slide rail and the chute. In other examples, the slide rail 14 and the chute are connected, and their extending directions are the same.

[0099] In some embodiments, the sliding member 16 has a mounting hole, and the roller 133 is rotatably arranged in the mounting hole. In this way, the rotational connection between the sliding member 16 and the roller 133 can be realized without other components.

[0100] Exemplarily, the roller 133 and the mounting hole are in clearance fit, and the roller 133 is inserted into the mounting hole. Again exemplarily, the roller 133 is rotatably arranged in the mounting hole through a bearing. In some examples, the rotating shaft 132 is rotatably arranged in the mounting hole through the roller 133.

[0101] In some embodiments, the sliding member 16 is provided with a bearing seat, and the roller 133 is rotatably arranged in the bearing seat.

[0102] In some embodiments, when at least part of the rack 122 drives a pair of gears 121 to rotate synchronously, the gears 121 rotate at a constant speed.

[0103] An embodiment of the present application further provides a battery assembly system. Refer to Figure 10 and Figure 11 , the battery assembly system is configured to install the electrode assembly 3 wrapped with an insulating protective film in the housing 2. In some examples, the battery assembly system is further configured to encapsulate the electrode assembly 3 in the housing 2 (i.e., snap the upper cover onto the housing 2) to form a battery. The embodiments of the present disclosure are described by taking the battery assembly system configured to install the electrode assembly 3 wrapped with an insulating protective film in the housing 2 as an example.

[0104] The battery assembly system may include a conveying device 4, an assembling device 5, and a flattening device 1; the conveying device 4 is used to convey the structures to be assembled to each station of the assembling device 5; the stations of the assembling device 5 include a housing inserting device 51; the housing inserting device 51 is used to insert the electrode assembly 3 into the housing 2 from the open end of the housing 2; when the electrode assembly 3 is inserted into the housing 2, a pair of rollers 133 of the flattening device 1 are used to clamp and flatten the electrode assembly 3 passing through the pair of rollers 133. In this way, by using the synchronous rotation of the housing inserting device 51 and the pair of rollers 133, the electrode assembly 3 is flattened and then installed in the housing 2, which can reduce the problem of wrinkles occurring in the insulating protective film wrapped outside the electrode assembly 3.

[0105] The conveying device 4 includes a conveying line. The conveying line can be a conveying structure formed by a conveying roller driven by a motor cooperating with a conveyor belt, or a conveying structure formed by articulated conveying chain links driven by a motor, or an AGV conveying cart, which can realize conveying in at least one direction and can support and ensure the stability of the structures to be assembled.

[0106] The housing inserting device 51 is a pushing mechanism or a clamping mechanism, which can stably move the electrode assembly towards the open end of the housing and enter the accommodation cavity through the open end. The pushing mechanism can be a cylinder, an electric push rod, etc. The clamping mechanism can be a vacuum chuck, a jaw mechanism, a fork mechanism, etc. In some embodiments, when a pair of gears 121 rotate synchronously, the linear velocity on the outer surface of the roller 133 is the same as the moving speed of the housing inserting device pushing the electrode assembly 3 between the pair of rollers 133. To reduce the problem of wrinkles caused to the insulating protective film of the electrode assembly 3 when the speeds of the two are different.

[0107] The electrode assembly 3 is an electrode assembly 3 wrapped with an insulating protective film. The material of the insulating protective film can be a material with insulating and protective functions, such as resin, etc.

[0108] The battery may include an end cap, a shell 2 and an electrode assembly 3. The shell 2 has an open end, and the end cap is snapped on the open end of the shell 2, together defining a receiving cavity for receiving the electrode assembly 3. That is, the electrode assembly 3 is installed in the shell 2 through the open end, and is snapped on the shell 2 through the end cap; so that the electrode assembly 3 is located in the receiving cavity. For example, the end cap and the shell 2 are connected by screws, snaps, etc. In some examples, the battery may be referred to as a battery cell. The battery cell may include a lithium-ion battery, a sodium-ion battery, or a magnesium-ion battery, etc. The battery cell may be cylindrical, flat, or in other shapes, etc. Battery cells are generally divided into three types according to the packaging method: cylindrical battery cells, square battery cells, and soft-pack battery cells.

[0109] In some embodiments, a pole is provided on the wall of the shell 2 opposite to the open end, and the pole has a through hole. The shell 2 and the end cover are connected to form a accommodating cavity connected to the through hole; the active material coating part of the electrode assembly 3 is arranged in the shell 2, and the pole ear part of the electrode assembly 3 passes through the through hole and is connected to the side of the pole away from the accommodating cavity.

[0110] The workstation of the assembly equipment 5 may also include a pole ear welding device, a pole ear piercing device, a pole column welding device and an end cap welding device. The pole ear welding device is used to weld multiple pole ear sheets of the electrode assembly to form a pole ear portion; the pole ear piercing device is used to clamp the pole ear portion through the through hole when the electrode assembly is installed in the shell; the pole column welding device is used to weld the pole ear portion passing through the through hole to the side of the pole away from the accommodating cavity.

[0111] The purpose of the pole lug welding device is to form the pole lug part after pre-welding the pole lug sheet. It can be an ultrasonic welding device, which can ensure that the pole lug is welded in a clamped and stable state. The pole lug piercing device can adopt a clamping structure or a guiding structure, which can guide the pole lug part to pass through the through hole smoothly without interfering with the shell. The pole column welding device aims to achieve the welding of the pole lug part and the pole column, and can be a laser welding device. The end cover welding device aims to achieve the circumferential edge welding of the end cover and the opening end of the shell, and is also a laser welding device.

[0112] In some embodiments, when the number of electrode assemblies 3 is multiple, for example, two, the assembly equipment 5 also includes a matching device, which is used to stack multiple electrode assemblies so that the pole tabs of two electrode assemblies are roughly opposite to each other, so that the conveying structure can convey the matched electrode assemblies to the pole tab welding device for welding the pole tab sheets to facilitate the formation of the pole tab portion.

[0113] In some embodiments, in order to ensure the reliability of the battery assembly process, a dust removal station, an NG detection station, etc. may be added between any two adjacent stations, which is not limited in this embodiment.

[0114] In some embodiments, when the distance between a pair of rollers 133 in the second direction Y gradually decreases to a preset spacing and then gradually increases as the rack 122 moves in the first direction X, during the process of the shell loading device 51 loading the electrode assembly 3 between the pair of rollers 133 into the shell 2, the rack 122 drives a pair of gears 121 to mesh, and under the cooperation of the elastic member 15, the pair of rollers 133 gradually approach each other in the second direction Y to a preset spacing. At the preset spacing, the pair of rollers 133 clamp the electrode assembly 3 and flatten the electrode assembly 3; then the pair of rollers 133 gradually move away from each other in the second direction Y and release the electrode assembly 3.

[0115] The gap between the two rollers 133 is aligned with the opening end of the shell 2. Flattening the electrode assembly 3 can be understood as that when the inclined electrode assembly 3 passes between the two rollers 133, the electrode assembly 3 is aligned with the opening end of the shell 2.

[0116] The above are only the embodiments of the present application, and do not limit the patent protection scope of the present application. Any equivalent structure or equivalent process transformation made by using the content of the specification and drawings of the present application, or directly or indirectly applied in other related technical fields, shall be similarly included in the patent protection scope of the present application.

Claims

1. A flattening device, characterized in that, it includes: a frame; a pair of cooperating rollers; the rollers are rotatably connected to the frame and are used for flattening the piece to be flattened; and, a driving mechanism, arranged on the frame and connected to the rollers, for driving the pair of rollers to rotate synchronously.

2. The flattening device according to claim 1, characterized in that, the driving mechanism includes a rack and a pair of gears; the gears are coaxially arranged with the rollers, and both of the pair of gears are engaged with the rack; the rack extends in a first direction and is capable of moving relative to the frame in the first direction; wherein, during the process of the rack moving in the first direction, at least part of the rack drives the pair of gears to rotate synchronously.

3. The flattening device according to claim 2, characterized in that, the flattening device further includes: an elastic member and a pair of sliding members; the sliding members are slidably connected to the frame, and the sliding members slide relative to the frame in a second direction; the rollers are rotatably connected to the sliding members; the elastic member is configured to drive the pair of sliding members to approach or move away from each other in the second direction; the second direction is perpendicular to the first direction and perpendicular to the axial direction of the rollers; wherein, as the rack moves in the first direction, the distance between the pair of rollers in the second direction first gradually decreases to a preset distance and then gradually increases.

4. The flattening device according to claim 3, characterized in that, along the second direction, the rack has two opposite tooth surfaces, and the pair of gears are respectively engaged on the two tooth surfaces of the rack; wherein, one of the two tooth surfaces is a concave tooth surface, and the other tooth surface is parallel to the first direction; or, both of the two tooth surfaces are concave tooth surfaces.

5. The flattening device according to claim 4, characterized in that, the concave tooth surface includes a first section of tooth surface, a second section of tooth surface and a third section of tooth surface connected in sequence; the second section of tooth surface is parallel to the first direction; along the first direction, the dimensions of multiple tooth structures of the first section of tooth surface gradually decrease first, and the dimensions of multiple tooth structures of the third section of tooth surface gradually increase first; wherein, the tooth structure dimension is the dimension between a tooth structure and the center line of the rack in the second direction; the center line extends in the first direction.

6. The flattening device according to claim 5, characterized in that, the included angle between the first section of tooth surface and the second section of tooth surface is 120° - 150°; and / or, the included angle between the third section of tooth surface and the second section of tooth surface is 120° - 150°.

7. The flattening device according to claim 4, characterized in that, the rack is symmetrically arranged with respect to the axis of symmetry parallel to the first direction and symmetrically arranged with respect to the axis of symmetry parallel to the second direction.

8. The flattening device according to claim 4, characterized in that, the elastic member includes two compression elastic members, the compression elastic members are connected between the frame and the sliding members, and the compression elastic members are located on the side where the two rollers are away from each other; or, The elastic member includes a tensile elastic member, and the tensile elastic member is connected between a pair of the sliding members.

9. The flattening device according to claim 3, wherein, the rack includes a first rack and a second rack arranged along the second direction; a pair of the gears are located between the first rack and the second rack and respectively mesh with the tooth surfaces of the first rack and the second rack; wherein, the tooth surface of the first rack is a convex tooth surface, and the tooth surface of the second rack is parallel to the first direction; or, the tooth surfaces of the first rack and the second rack are both convex tooth surfaces.

10. The flattening device according to any one of claims 3 to 9, wherein, the flattening device further includes a slide rail, the slide rail is arranged on the frame, and the sliding member is slidably arranged on the slide rail; or, the frame has a chute, and the sliding member is slidably arranged on the chute.

11. The flattening device according to any one of claims 3 to 9, wherein, the sliding member has a mounting hole, and the roller is rotatably arranged in the mounting hole.

12. A battery assembly system, wherein, it includes a conveying device, an assembling device and the flattening device according to any one of claims 1 to 11; the conveying device is used to convey the structure to be assembled to each station of the assembling device; the stations of the assembling device include a case loading device; the case loading device is used to load the electrode assembly into the case from the open end of the case; when the electrode assembly is loaded into the case, a pair of rollers of the flattening device are used to clamp and flatten the electrode assembly passing through the pair of rollers.

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