Tab pre-pressing device and turret mechanism

Abstract

This invention discloses a tab pre-compression device for bending the tabs of a battery cell wound on a winding needle. The device includes a shaft and a pre-compression unit mounted on the shaft. The shaft is parallel to the winding needle. The pre-compression unit includes a pre-compression surface for bending the tabs of the battery cell. The shaft is elastically mounted on a base, and a support unit is provided on the shaft. This support unit supports the battery cell and elastically compresses the shaft towards the base. This invention can pre-compress and bend the tabs at a specific angle during the battery cell winding process. Furthermore, it can gradually move away from the winding needle as the battery cell diameter increases to pre-compress and bend the outermost tabs of the battery cell, thus improving the tab pre-compression effect.

Description

Technical Field

[0001] This invention belongs to the field of lithium battery automation equipment, and particularly relates to a cell winding device. Background Technology

[0002] In lithium battery production, a strip of material consisting of a positive electrode, a negative electrode, and a separator is wound to form a battery cell. Several tabs are set or formed on the positive and negative electrode sheets; these tabs are metal conductors that lead out the positive and negative electrodes. Conventional wound battery cells have different structures such as single-tab, multi-tab, and all-tab, with the tabs stacked at one or both ends of the wound cell. After the battery cell is wound, the tabs need to be bent uniformly towards the center of the cell's cross-section; this process is called tab shaping. The shaped tabs converge inwards, facilitating the insertion of the battery cell into the casing.

[0003] Typically, tab shaping is performed after the battery cell is wound. Because the tabs are stacked after winding, bending them is difficult and the shaping effect is poor. Summary of the Invention

[0004] To address the problems existing in the background technology, the present invention provides a device for pre-compressing the tabs during the battery cell winding process, and a turret mechanism with a tab pre-compressing device.

[0005] The tab pre-compression device provided by this invention is used to bend the tabs of a battery cell wound on a winding needle. The tab pre-compression device includes a shaft and a pre-compression unit mounted on the shaft. The shaft is arranged parallel to the winding needle. The pre-compression unit includes a pre-compression surface for bending the tabs of the battery cell. The shaft is elastically mounted on a base, and a support unit is provided on the shaft. This support unit supports the battery cell and elastically compresses the shaft to one side of the base.

[0006] In one embodiment of the tab pre-compression device of the present invention, two guide rods are arranged on the shaft perpendicular to its axis, and a spring is sleeved on each guide rod and respectively disposed in a guide hole of the base. One end of the spring abuts against the shaft and the other end abuts against the base.

[0007] In one embodiment of the tab preloading device of the present invention, a linear bearing is provided in the guide hole, and the free end of the guide rod is provided in the linear bearing.

[0008] In one embodiment of the electrode pre-compression device of the present invention, two movable rails are arranged perpendicularly to the axis of the shaft, and two fixed rails are arranged on the base. The two movable rails and the two fixed rails cooperate to form two slide rail structures. A spring is arranged on each slide rail structure, and the spring is arranged between the shaft and the base.

[0009] In one embodiment of the tab preloading device of the present invention, the two ends of the shaft are rotatably mounted on the base along its axis; the preloading unit and the support unit are respectively fixedly mounted on the shaft, and the preloading surface of the preloading unit is implemented by adopting a conical surface.

[0010] In one embodiment of the electrode pre-compression device of the present invention, the conical surface has a large cross-section end and a small cross-section end, wherein the small cross-section end is disposed opposite to the support unit, and the diameter of the small cross-section end is equal to the diameter of the support unit.

[0011] In one embodiment of the electrode pre-compression device of the present invention, the pre-compression unit includes a cylindrical body, the cross-sectional diameter of the cylindrical body is equal to the diameter of the smaller end of the pre-compression surface, and the cylindrical body is supported on the side wall of the battery cell, and the smaller end of the pre-compression surface contacts the root of the electrode.

[0012] In one embodiment of the electrode pre-compression device of the present invention, both ends of the shaft are fixedly disposed on the base; the support unit is rotatably disposed on the shaft, and the pre-compression unit is fixed on the shaft and has a pre-compression surface that bends toward the electrode.

[0013] The present invention also discloses a turret mechanism, including a main turret and a secondary turret arranged opposite to each other, a main shaft fixedly connected between the main turret and the secondary turret, and multiple sets of winding needles respectively provided on the main turret and the secondary turret. The turret mechanism also includes multiple sets of electrode pre-pressing devices, the base of which is fixedly mounted on the main shaft, and the shaft of which is parallel to the winding needles.

[0014] In another embodiment, the turret mechanism includes a circular turntable and a coiling needle disposed at its center, the coiling needle being rotatable about its axis and extending and retracting from the surface of the turntable. The turret mechanism also includes a set of tab preload devices mounted on one side of the coiling needle, with the axis of the tab preload devices parallel to the coiling needle.

[0015] In summary, the present invention, through a pre-compression unit arranged parallel to the winding needle, can pre-compress and bend the tabs of the battery cell at a specific angle during the winding process. At the same time, as the diameter of the battery cell gradually increases, it can gradually move away from the winding needle to pre-compress and bend the outermost tabs of the battery cell, thereby improving the pre-compression effect of the tabs. Attached Figure Description

[0016] Figure 1 This is a structural diagram of an embodiment of the turret mechanism of the present invention;

[0017] Figure 2 yes Figure 1 A sectional view of the transfer tower mechanism along line II-II;

[0018] Figure 3 yes Figure 1 A structural diagram of a set of electrode pre-compression devices and a set of winding needles;

[0019] Figure 4 yes Figure 3 Structural diagram of the intermediate preload unit;

[0020] Figure 5 yes Figure 3 Installation structure diagram of the middle support unit and shaft;

[0021] Figure 6 This is a structural diagram of another embodiment of the turret mechanism of the present invention;

[0022] Figure 7 yes Figure 6 Structural diagram of the intermediate preload unit;

[0023] Figure 8 This is a structural diagram of another embodiment of the electrode pre-compression device of the present invention. Detailed Implementation

[0024] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, so that those skilled in the art can better understand and implement the present invention. However, the embodiments described are not intended to limit the present invention.

[0025] like Figure 1 , Figure 2 As shown, a turret mechanism 100 according to an embodiment of the present invention includes a main turret 101, a secondary turret 102, and a main shaft 103 disposed on the axis of the main turret 101 and the secondary turret 102. The main shaft 103 is fixedly connected to the main turret 101 and the secondary turret 102, thus ensuring that the two rotate synchronously. A winding station P1, an adhesive application station P2, and a material unloading station P3 are evenly arranged around the center of the main turret 101, and a first winding needle 110 is provided at each station. A second winding needle 120 is provided on the secondary turret 102 corresponding to the aforementioned stations P1-P3. The first winding needle 110 and the second winding needle 120 located at the same station extend relative to each other under the drive of their respective motors to form a winding needle group. This winding needle group can clamp the material strip composed of the positive electrode sheet, the negative electrode sheet, and the separator, and wind the material strip onto the winding needle group to form a battery cell C. After the battery cell C is wound, it is coated with adhesive to prevent it from unraveling. Then, the first winding needle 110 and the second winding needle 120, driven by their respective motors, retract relative to each other and are pulled out of the battery cell, allowing it to be removed by a clamping unit. The main turret 101 and the auxiliary turret 102 rotate around the main shaft 103, thus enabling different winding stages of the battery cell to be performed at corresponding workstations. The structure and operation of the turret mechanism described above are conventional designs in this field and will not be detailed here.

[0026] This embodiment illustrates the concept of the invention in conjunction with the turret mechanism for inserting pins. "Inserting pins" refers to the first coil of pins 110 and the second coil of pins 120 being arranged opposite each other along their axial direction; their extension action involves the two coils of pins moving closer together, and their retraction action involves the two coils of pins moving further apart. However, turret mechanisms for inserting pins in the same direction also exist in the art, where the extension and retraction actions of the first and second coils of pins are achieved in the same direction. This type of turret mechanism is described in Chinese Invention Patent Application No. CN111403823A and will not be repeated here. As can be seen from the following description, the tab pre-compression device of the present invention can be applied indiscriminately to both turret mechanisms for inserting pin structures and turret mechanisms for inserting pins in the same direction.

[0027] like Figure 3 As shown, in one embodiment of the present invention, a tab pre-compression device 200 is mounted on the main shaft 103 of the turret mechanism 100, including a base 210 and a shaft 220 elastically disposed on the base 210. At least one pre-compression unit 230 for bending the tab and a support unit 240 for supporting the outer wall of the battery cell C are mounted on the shaft 220. The pre-compression unit 230 has a pre-compression surface 231 inclined at an angle to the axis of the shaft 220. The inclination angle of the pre-compression surface 231 depends on the bending angle of the tab, thus enabling the tab of the battery cell C to be bent at a predetermined angle in a predetermined direction (usually towards the battery cell axis).

[0028] like Figure 4 As shown, the preload unit 230 in this embodiment is implemented using a conical wheel. The main body of the conical wheel is cylindrical, and a mounting hole 232 is opened through its axis for fixed installation on the shaft 220. One end of the conical wheel has a conical surface that serves as the aforementioned preload surface 231. The generatrix of the conical surface extends toward its axis and thus forms an inclined surface that is inclined toward the axis. The inclination angle is determined by the aforementioned bending angle of the tab.

[0029] For ease of installation, the cylindrical main body of the conical wheel is cut to form a main body 233 and a retaining ring 234, each with a semi-circular slot. When the two are assembled together, the two slots together form the mounting hole 232. A first threaded hole 2331 is provided on the main body 233, and a second threaded hole 2341 is provided on the retaining ring 234. When the two are engaged, the first and second threaded holes 2331 and 2341 can be locked with screws to install the conical wheel onto the shaft 220. By loosening the screws, the position of the conical wheel on the shaft 220 can be quickly adjusted so that the preload surface 231 is aligned with the tabs of cells of different lengths.

[0030] like Figure 5As shown, the support unit 240 in this embodiment is implemented using a rubber-coated wheel. The side of the rubber-coated wheel is a flat cylindrical surface, which is used to support the battery cell C. The rubber-coated wheel is sleeved on the shaft 220 through a central opening. A locking groove 221 is formed on the shaft 220 along its axial direction, and multiple fixing holes 241 are formed on the rubber-coated wheel along its radial direction. The rubber-coated wheel can be fixed by screwing it into the fixing holes 241 and abutting against the bottom surface of the locking groove 221 or screwing it into the shaft 220. The two ends of the shaft 220 are used to install the aforementioned preload unit 230.

[0031] See also Figure 3 As for Figure 5 The two ends of the shaft 220 are respectively installed in the bearings of a bearing housing 300, so that the shaft 220, together with the preload unit 230 and the support unit 240 mounted on it, can rotate freely around its axis. This installation method can transform the friction between the battery cell C and the support unit 240 into rolling friction, reducing the frictional force of the support unit 240 on the battery cell C. A guide rod 310 is fixedly connected to the bearing housing 300 in a direction perpendicular to the shaft 220. One end of the guide rod 310 can be installed into the bearing housing 300 with screws, thereby achieving fixed installation.

[0032] The base 210 is generally flat, with a guide hole 211 extending through each end. A gasket 212 or a stepped surface structure is installed inside the guide hole 211, thereby reducing the diameter of the guide hole 211 at that point. A spring 320 is fitted onto the guide rod 310 on the aforementioned shaft 220 and then inserted into the guide hole 211. In this way, the spring 320 is located between the gasket 212 and the bearing seat 300, allowing the shaft 220 to be elastically mounted onto the base 210. When the shaft 220 is subjected to external pressure, it can compress the spring 320 to achieve movement in a direction perpendicular to its axis; when the external force is removed, the shaft 220 can return to its original position under the action of the spring.

[0033] To ensure smooth movement of the shaft 220, a linear bearing 213 is also installed inside the guide hole 211. The guide rod 310 is inserted into the linear bearing 213, and a washer is installed at its end with a screw to prevent it from slipping out of the linear bearing 213. In other embodiments, the linear bearing and guide hole can also be replaced by a damping slide rail or a regular slide rail. The guide rod 310, as the movable rail of the slide rail, directly cooperates with the fixed rail set on the base 210, which can also achieve the function of smooth movement of the shaft 220.

[0034] Continue reading Figure 5In this embodiment, the base 210 body is also provided with a cutter base plate 400 for use with a diaphragm cutter. The cutter base plate 400 has a cutter groove 410 parallel to the shaft 220 for accommodating the diaphragm cutter. The cutter base plate 280 has a waist-shaped hole 420 that mates with a threaded hole. The cutter base plate 400 can be fixed to the base 210 through the waist-shaped hole 420 and the corresponding threaded hole on the base 210, and the installation position of the cutter base plate 400 can be adjusted through the waist-shaped hole 420 so that the cutter groove 410 aligns with the position of the diaphragm cutter. The waist-shaped hole 420 can be long enough to ensure that the edge of the cutter base plate 400 does not obstruct the movement of the pre-compression unit 230 and the support unit 240 with the shaft 220. In this embodiment, two waist-shaped holes 420 and two cutter grooves 410 are provided on the same side, allowing for sufficient adjustment of the position of the cutter base plate 400 relative to the base 210.

[0035] See also Figures 1 to 5 In this embodiment, the turret mechanism 100 is equipped with a set of tab pre-compression devices 200 for each winding needle group, and the shaft 220 of the tab pre-compression device 200 is kept parallel to the corresponding winding needle group. When the winding needle group starts to wind the battery cell, the support unit 240 on the shaft 220 presses the winding battery cell C tightly, which can prevent the battery cell from unraveling. At the same time, the pre-compression surfaces 231 of the two pre-compression units 230 contact the tabs of the battery cell, and the end with the smaller cross-section of the pre-compression surface 231 contacts the root of the tab, and the end with the larger cross-section of the pre-compression surface 231 contacts the free end of the tab. This ensures that the tab bends at an angle along the pre-compression surface 231. As the diameter of the battery cell increases during winding, the support unit 240 applies an external pushing force to the shaft 220, and the shaft 220 further compresses the spring 320, thereby sliding in the guide hole 211 of the base 210 and adapting to the gradual increase in the size of the battery cell while ensuring proper contact with the battery cell. In this way, the tabs of the battery cell can be shaped during the winding process.

[0036] As can be seen from the above description, in this embodiment, the diameter of the rubber-coated wheel is basically equal to the diameter of the smallest position of the conical wheel. This ensures that when the rubber-coated wheel is supported on the battery cell, the smaller end of the pre-compression surface 231 in the conical wheel fits exactly against the root of the tab.

[0037] In the above embodiments, two pre-pressure units 230 are provided. However, it can be clearly seen that when the battery cell specification is that the tab is set on one side, the corresponding tab pre-pressure device can be set with only one pre-pressure unit 230.

[0038] Figure 6In another embodiment of the invention, the turret mechanism has unidirectional insertion needles and only one set of needles. In this structure, the turret mechanism includes a circular turntable 150 and a set of needles 151 disposed on the turntable 150. The needles 151 can rotate around their axis and extend and retract from the surface of the turntable 150. The entire process of winding the battery cell is completed at the same station. Since there is no main shaft structure for mounting the tab preloading device, the base 210 of the tab preloading device can be directly or indirectly mounted on other components of the winding machine, such as a large plate.

[0039] In this embodiment, the pre-compression unit also functions as a support unit. For example... Figure 7 As shown, in this embodiment, the generatrix of the tapered pre-compression surface 511 of the pre-compression unit 510 is formed by expanding outward along the axis of its cylindrical body 512. When shaping the electrode tab, the cylindrical body 512 of this pre-compression unit can be supported on the battery cell C. The smaller end of the tapered pre-compression surface 511 aligns with the root of the electrode tab, while the larger end bends inward toward the free end of the electrode tab. Similarly, the pre-compression unit 510 can adopt a split structure design and be fixed to the shaft 220 with screws. The shaft 220 is rotatably assembled via the bearing seat 300 and mounted to the base 210 via the spring 320. The specific structure can be implemented as in the previous embodiment, and will not be repeated here. It should be noted that a separate support unit can also be provided in this embodiment as needed.

[0040] Figure 8 These are modifications made to the foregoing embodiments based on the inventive concept, and these modifications are equally applicable to... Figure 1-5 Implementation examples and Figure 6-7 In this embodiment, the shaft 220' of the electrode preload device is directly fixed to a mounting base 300', and the shaft 220' cannot rotate along its axis within the mounting base 300'. The support unit 240' is mounted to the shaft 220' via a bearing 241', meaning the support unit 240' can rotate on the shaft 220'.

[0041] In this modified scheme, the pre-compression unit 230' in the aforementioned embodiment is also fixedly mounted on the shaft 220', meaning that neither the pre-compression unit 230' nor the shaft 220' rotates. Since the pre-compression unit 230' does not need to rotate around the axis, only one pre-compression surface needs to face the tab to achieve tab shaping. That is, the pre-compression unit 230' can be in the form of a pre-compression sheet instead of using a tapered wheel.

[0042] Similarly, it can be seen that in the pre-compression unit 230' of the pre-compression sheet form, the pre-compression surface can also adopt two design options: one is as follows Figure 7The free end of the pre-pressed sheet is shown in two forms: one is the form of the free end of the pre-pressed sheet at the root of the pre-pressed sheet at the free end of the pre-pressed sheet, and in the second design, the free end of the pre-pressed surface extends toward the axial direction of shaft 220'.

[0043] The above embodiments are merely preferred embodiments provided to fully illustrate the present invention, and the scope of protection of the present invention is not limited thereto. Equivalent substitutions or modifications made by those skilled in the art based on the present invention are all within the scope of protection of the present invention. The scope of protection of the present invention is defined by the claims.

Claims

1. A tab pre-compression device for bending the tabs of a battery cell wound on a winding needle, comprising a shaft and a pre-compression unit mounted on the shaft, the shaft being parallel to the winding needle, the pre-compression unit including a pre-compression surface for bending the tabs of the battery cell; characterized in that, The shaft is elastically mounted on a base, and a support unit is provided on the shaft. The support unit is used to support the battery cell and elastically compress the shaft to one side of the base. Two guide rods are arranged on the shaft perpendicular to its axis. A spring is sleeved on each guide rod and is respectively disposed in a guide hole of the base. One end of the spring abuts against the shaft and the other end abuts against the base. Both ends of the shaft are rotatably mounted on the base along its axis; the pre-loading unit and the support unit are respectively fixedly mounted on the shaft, and the pre-loading surface of the pre-loading unit is a conical surface; The conical surface has a large cross-section at one end and a small cross-section at the other end, wherein the small cross-section at one end is disposed opposite to the support unit, and the diameter of the small cross-section at one end is equal to the diameter of the support unit. The pre-compression unit includes a cylindrical body with a cross-sectional diameter equal to the diameter of the smaller end of the pre-compression surface. The cylindrical body is supported on the side wall of the battery cell, and the smaller end of the pre-compression surface contacts the root of the tab.

2. The electrode pre-compression device as described in claim 1, characterized in that, A linear bearing is installed inside the guide hole, and the free end of the guide rod is installed inside the linear bearing.

3. The electrode pre-compression device as described in claim 1, characterized in that, Two movable rails are arranged perpendicular to the axis of the shaft, and two fixed rails are arranged on the base. The two movable rails and the two fixed rails cooperate to form a two-slide rail structure. A spring is arranged on each slide rail structure and the spring is arranged between the shaft and the base.

4. The electrode pre-compression device as described in claim 1, characterized in that, Both ends of the shaft are fixedly mounted on the base; the support unit is rotatably mounted on the shaft, and the pre-compression unit is fixed on the shaft and has a pre-compression surface that bends toward the tab.

5. A turret mechanism, comprising a main turret and an auxiliary turret arranged opposite to each other, wherein a main shaft is fixedly connected between the main turret and the auxiliary turret, and wherein the main turret and the auxiliary turret are respectively provided with multiple sets of winding needles; characterized in that, It also includes multiple sets of tab pre-compression devices as described in claim 1, wherein the base of the tab pre-compression device is fixedly mounted on the main shaft, and the shaft of the tab pre-compression device is parallel to the winding needle.

6. A turret mechanism comprising a circular turntable and a coiled needle disposed at its center, the coiled needle being rotatable about its axis and extending from and retracting from the surface of the turntable; characterized in that, It also includes a set of tab pre-compression devices as described in claim 1, wherein the tab pre-compression devices are installed on one side of the winding needle, and the axis of the tab pre-compression devices is parallel to the winding needle.

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