Full-tab shaping device and full-tab shaping method

Abstract

The invention discloses a full-tab shaping device and a full-tab shaping method, which are characterized in that two-time lodging shaping is carried out on a tab, a tab flattening, cutting and stacking process is replaced, tab positioning is carried out during two-time shaping, so that the tab which does not need to be lodged is prevented from lodging, the tab lodging is towards one direction, and metal chips or laser rays are prevented from entering a roll core gap. The primary shaping positioning assembly is used for covering the tabs and providing lodging guidance for the primary shaping assembly, so that the primary shaping precision is improved, and the operation difficulty is reduced; the primary shaping assembly is used for applying axial pressure of a winding core to a to-be-lodged tab, so that the tab is primarily lodged; the initially lodging tabs lodging towards the central hole of the roll core, so that the risk of short circuit caused by the fact that laser rays or metal chips possibly generated in the welding process enter gaps of the roll core can be effectively prevented, the qualification rate of roll core production is improved, the deep shaping of the tabs and the welding of the current-carrying disc share a station and are realized at the position of the detachable current-collecting disc carrier, and the production efficiency is improved. Production space can be saved, and machining efficiency is improved.

Description

Technical Field

[0001] The present invention belongs to the field of lithium batteries, and particularly relates to a full-tab shaping device and a full-tab shaping method. Background Art

[0002] The full-tab battery technology is an important innovation direction in the field of lithium batteries in recent years. Its core lies in optimizing the single / double-tab structure of traditional batteries into directly using the uncoated areas of the positive / negative current collectors as tabs. Through the full-area connection between the tabs and the current collector plate, the internal resistance and heat generation of the battery can be significantly reduced, effectively solving the thermal runaway problem under high-rate charge and discharge.

[0003] The tab shaping of the core is a key step in the manufacture of full-tab batteries, involving processes such as cutting and folding, and rubbing.

[0004] The rubbing process uses a local radial rubbing device to gradually press down the tabs from the outer edge of the core to the center, flattening the originally erected tabs into a dense plane, thereby increasing the contact area with the current collector plate during welding. However, during the process of rubbing the tabs, a certain amount of tab metal chips will inevitably be generated, greatly increasing the risk of short circuit. At the same time, the rubbing degree is uneven, easily causing problems such as virtual soldering of the shell.

[0005] The cutting and folding process is a process before winding. It mainly cuts a partial area of the tab of the electrode sheet through a laser, divides it into multiple continuous small tabs, and then bends and shapes the stacked tabs after winding. Its disadvantages are high equipment investment cost, strict requirements for process parameters such as laser power, cutting speed, and tension control, difficult machine adjustment, and micro-cracks or damage are easily generated on the copper-aluminum foil tabs due to the thermal effect during the cutting process, requiring additional detection and screening, significantly reducing production efficiency; in addition, during the winding process, the tabs are easily wrinkled and bent and then wound into the core, increasing the defective rate of the core.

[0006] In the patent CN115395074A "A Tab Shaping Method for a Full-Tab Cylindrical Core", a shaping method that does not require rubbing and cutting is given, but its invention has the following disadvantages: 1. The size of the tab shaping head and the size, quantity, and size of the convex points on the end face distribution are fixed, only applicable to cores of specific size specifications, with relatively single functions and not high practical value; 2. There is no core clamping and shaping positioning device, resulting in difficult operation during the shaping process, difficult to control the accuracy of the directional lodging of the tabs, and poor consistency of the shaping effect; 3. After shaping, the tab and the current collector plate are welded on the side of the tab, and the contact area between the two is small, thereby increasing the probability of virtual soldering, reducing the qualified rate of the core. At the same time, welding the current collector plate on the side will cause difficulties in encapsulation and inserting the core into the shell, increasing the difficulty of a series of subsequent assembly operations and being difficult to apply to actual production. Summary of the Invention

[0007] In response to the deficiencies described in the above-mentioned prior art, the present invention provides a full-tab shaping device and a full-tab shaping method, which perform two-time bending shaping on the tabs to eliminate the flattening and cutting and stacking tab processes. The tabs are positioned during both shaping processes to avoid bending of tabs that do not need to be bent, and the tabs are bent in one direction, preventing metal chips that may be generated by laser light or welding from entering the gap between the winding cores.

[0008] The technical solution adopted in the present invention is: A full tab shaping method, comprising the following steps: S1, use the primary shaping device to perform primary shaping on the tabs of the full-tab core, so that the tabs welded to the collector plate are initially tilted toward the center hole of the core; the tabs near the center hole of the core are not tilted, that is, the tilted tabs are from the outermost layer of the core to a certain distance from the center hole of the core, which is generally 2-3 turns outside the center hole of the core; The primary shaping device includes a primary shaping positioning assembly and a primary shaping assembly; the primary shaping positioning assembly is used to cover the tabs and provide a falling guide for the primary shaping assembly, thereby improving the accuracy of the primary shaping and reducing the difficulty of operation; the primary shaping assembly is used to apply axial pressure of the winding core to the tabs to be fallen, so that the tabs are initially fallen; the initially fallen tabs all fall toward the center hole of the winding core, which can effectively prevent the laser light during welding or metal chips that may be generated during the welding process from entering the gap of the winding core, thereby reducing the risk of causing short circuits and improving the qualified rate of winding core production; S2, using a depth shaping device to perform depth shaping on the initially fallen tab and weld the collector plate, the depth shaping increasing the fallen depth of the tab; The depth shaping device includes a detachable current collecting plate carrier and a pressure tool. The detachable current collecting plate carrier is provided with a current collecting plate welding groove, and a plurality of current collecting plate welding clearance holes are provided in the current collecting plate welding groove; the current collecting plate welding clearance holes correspond one to one with the areas to be welded of the current collecting plate; the pressure tool provides the detachable current collecting plate carrier with pressure along the axial direction of the winding core to deepen the depth of the tab. Deep shaping can not only avoid the tab rebounding after the initial shaping, affecting the welding effect, but also ensure that the tab lying area includes the area welded with the current collecting plate, ensuring the concentricity requirements of the current collecting plate and the winding core. Moreover, the depth shaping of the tab and the current collecting plate welding share a common workstation and are both implemented at the detachable current collecting plate carrier, which can save production space and improve processing efficiency.

[0009] As a preferred embodiment of the present invention, the specific steps of the initial shaping are: S11, before the initial shaping, use the core clamping assembly to clamp the full-tab core, and make the tabs of the full-tab core protrude from the core clamping assembly by a certain length; the core clamping assembly clamps the wound full-tab core tightly, and makes the tabs of the core protrude from the core clamping assembly, preparing for the initial shaping; S12. Use the initial shaping and positioning component to position the tab. The initial shaping and positioning component is provided with a tab receiving groove and a lodging guiding groove. The tab receiving groove covers the tab that exposes the core holding component. The lodging guiding groove is arranged radially along the tab receiving groove and communicates with the tab receiving groove. The shape formed by each lodging guiding groove is the same as the shape of the welding area of the current collector plate. The shape of the lodging guiding groove is a fan blade shape or a shape similar to a fan blade, which is the same as the welding area of the current collector plate. And the size of the tab receiving groove is slightly larger than the core diameter, and the depth is also greater than the length of the exposed tab, so that all the tabs that expose the core holding component can be covered, which can weaken the influence of the tabs in the shaping area on the tabs that do not need to be shaped beside during initial shaping. S13. Under the guiding action of the lodging guiding groove, the initial shaping component applies a pressure along the axial direction of the core to the tab corresponding to the lodging guiding groove, so that the tab is initially lodged towards the core center hole direction. The tab lodged after a single extrusion is the area corresponding to the lodging guiding groove, which can avoid generating debris during the lodging process. That is, in the radial direction of the tab receiving groove, the initial shaping component does not need to move and extrude multiple times. The initial shaping component only extrudes multiple times along the axis of the tab receiving groove to ensure that all the tabs to be lodged are lodged.

[0010] As a preferred embodiment of the present invention, the specific steps of deep shaping are as follows: S21. Remove the initial shaping device. S22. Place the current collector plate on the back of the current collector plate welding groove, install the detachable current collector plate carrier of the current collector plate on the core holding component, and make the current collector plate contact the initially lodged tab. S23. The pressing tool provides a pressure along the axial direction of the core, so that the detachable current collector plate carrier extrudes the initially lodged tab to increase the lodging depth of the tab. S24. Weld the current collector plate and the lodged tab at the current collector plate welding relief hole. S25. Remove the deep shaping device and the core holding component.

[0011] The present invention also provides a full tab shaping device, including a core holding component, and also including an initial shaping device. The preliminary shaping device includes an initial shaping and positioning component and an initial shaping component. The initial shaping and positioning component is detachably connected to the core holding component. The initial shaping and positioning component is provided with a tab receiving groove and a lodging guiding groove. The tab receiving groove covers the tab that exposes the core holding component. The lodging guiding groove is arranged radially along the tab receiving groove and communicates with the tab receiving groove. The initial shaping component applies a pressure along the axial direction of the core to make the tab corresponding to the lodging guiding groove initially lodge towards the core center hole direction.

[0012] As a preferred embodiment of the present invention, it further includes a depth shaping device. The depth shaping device includes a detachable current collector tray carrier and a pressing tool. The detachable current collector tray carrier is provided with a current collector tray assembly position. The detachable current collector tray carrier is detachably connected to the core clamping assembly, and the current collector tray at the current collector tray assembly position is in contact with the tab. The detachable current collector tray carrier is provided with a current collector tray welding groove, and a plurality of current collector tray welding relief holes are arranged in the current collector tray welding groove. The current collector tray welding relief holes correspond to the welding areas to be welded of the current collector tray one by one, and the shapes of the current collector tray welding relief holes and the welding areas of the current collector tray are the same, both being fan-shaped or fan-like. As the welding station of the current collector tray, the pressing tool provides a pressure along the axial direction of the core to deepen the lodging depth of the tab. The pressing tool can use a locking bolt to apply pressure or use a clip to clamp for pressure application, as long as it can provide the pressure along the axial direction of the core.

[0013] As a preferred embodiment of the present invention, the initial shaping and positioning assembly includes an initial shaping and positioning plate. The end face of the initial shaping and positioning plate facing the tab is provided with a tab receiving groove, and the tab receiving groove coincides with the axis of the core center hole. The end face of the initial shaping and positioning plate away from the tab is provided with a plurality of lodging guiding grooves. Each lodging guiding groove radiates outward with the axis of the tab receiving groove as the center. The minimum distance between each lodging guiding groove and the axis of the tab receiving groove is greater than zero, ensuring that the core center hole and the tabs around it will not be pressed and remain vertical. Each lodging guiding groove communicates with the tab receiving groove, enabling the initial shaping lodging head of the initial shaping assembly to extend into the tab receiving groove to squeeze the tab.

[0014] As a preferred embodiment of the present invention, the initial shaping assembly includes an initial shaping fixed plate, an initial shaping moving plate, an initial shaping lodging head, and an elastic connecting member; the initial shaping fixed plate and the initial shaping moving plate are connected by the elastic connecting member, and the distance between the initial shaping fixed plate and the initial shaping moving plate is adjusted by the elastic connecting member. This distance serves as the moving space of the initial shaping moving plate, that is to say, the elastic space of the elastic connecting member corresponds to the lodging depth of the tab of the initial shaping; the initial shaping fixed plate is located on the initial shaping positioning plate; the initial shaping fixed plate is provided with a lodging head guiding hole, and the lodging head guiding hole corresponds to the lodging guiding groove; the initial shaping moving plate is provided with a lodging head mounting hole, and the initial shaping lodging head is fixedly installed at the lodging head mounting hole, and the working end of the initial shaping lodging head passes through the lodging head mounting hole and the lodging head guiding hole and then extends into the lodging guiding groove; the initial shaping moving plate bearing the axial pressure drives the initial shaping lodging head to extrude the tab; after the axial pressure disappears, under the restoring force of the elastic connecting member, the initial shaping moving plate drives the initial shaping lodging head to reset. In the initial state, the initial shaping lodging head extends into the tab accommodating groove and contacts the end of the tab. After being pressed, the initial shaping lodging head extrudes the tab to make it all tilt towards the center hole of the core. The size of the initial shaping lodging head is slightly smaller than that of the lodging guiding groove, so that it can reciprocate along the lodging guiding groove on the axis of the core, and the initial shaping lodging head makes all the tabs corresponding to the lodging guiding groove tilt after being extruded once, which can avoid debris falling into the core gap during the extrusion process.

[0015] As a preferred embodiment of the present invention, the elastic connecting member includes a guiding bolt, a spring, and an adjusting nut. One end of the guiding bolt passes through the initial shaping moving plate and is fixedly connected to the initial shaping fixed plate, and the other end of the guiding bolt protrudes from the initial shaping moving plate and is threadedly connected to the adjusting nut; the initial shaping moving plate can reciprocate along the guiding bolt; the spring is arranged between the initial shaping fixed plate and the initial shaping moving plate, and the deformation amount of the spring is the lodging depth of the initial shaping tab. In order to prevent the spring from shaking or tilting, spring installation grooves can be provided on the end faces of both the initial shaping fixed plate and the initial shaping moving plate.

[0016] The beneficial effects of the present invention are as follows: 1. After the tabs are shaped and then welded to the current collector plate, compared with the tabs without shaping, the contact area between the tabs and the current collector plate can be increased, the welding tensile force can be improved, and the defect rates of false soldering and missed soldering can be reduced, thereby overall improving the reliability of the welding.

[0017] 2. The tabs are initially shaped to make the tabs in the welding area lodge in the same direction, which can effectively prevent laser light or metal chips that may be generated during the welding process from entering the core gap, reduce the risk of causing a short circuit, and effectively improve the production qualification rate.

[0018] 3. By initially shaping and deeply shaping the tabs to achieve the directional lodging of the tabs, the operation process is convenient, no new equipment needs to be invested, the processes of flattening or cutting and overlapping the tabs can be replaced, and the equipment cost can be significantly reduced.

[0019] 4. An ear initial shaping and positioning component is provided, which can reduce the operation difficulty, improve the shaping accuracy, and improve the consistency of the ear lodging process.

[0020] 5. A common working position for the ear deep shaping and the current collector welding is provided. After the ear deep shaping is completed, the current collector welding can be carried out immediately, which can save the floor area of the production workshop, improve the production efficiency, and have the feasibility of mass production. Brief Description of the Drawings

[0021] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0022] Figure 1 It is a structural diagram of the negative ear of the present invention before shaping.

[0023] Figure 2 It is a structural diagram of the negative ear of the present invention after initial shaping.

[0024] Figure 3 It is a structural diagram of the negative ear of the present invention after deep shaping.

[0025] Figure 4 It is an assembly schematic diagram of the initial shaping device and the core holding component of the present invention.

[0026] Figure 5 It is an exploded view of the assembly of the initial shaping device and the core holding component of the present invention.

[0027] Figure 6 It is an assembly schematic diagram of the bolt pressure type deep shaping device and the core holding component of the present invention.

[0028] Figure 7 It is an exploded view of the assembly of the bolt pressure type deep shaping device and the core holding component of the present invention.

[0029] Figure 8 It is an assembly schematic diagram of the clip pressure type deep shaping device and the core holding component of the present invention.

[0030] Figure 9 It is a comparison chart of the battery performance curves of Example 1, Comparative Example 1, Comparative Example 4, Comparative Example 6, and Comparative Example 7 of the present invention. Detailed Embodiments

[0031] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without creative work are within the scope of protection of the present invention.

[0032] The present invention provides a full tab shaping device, comprising a winding core holding assembly 1, a primary shaping device and a deep shaping device. The tab undergoes primary shaping and deep shaping. During the primary shaping, the winding core holding assembly 1 and the primary shaping device are assembled. Figure 4 and 5 As shown, after the initial shaping is completed, the initial shaping device is removed, and the core clamping component 1 and the deep shaping device are assembled, as shown in FIG. Figure 6 and 7 shown.

[0033] The core clamping assembly 1 is mainly used to clamp the full-ear core, and includes a first buckle plate 11, a second buckle plate 12 and a buckle plate connecting column 13; the opposite end faces of the first buckle plate 11 and the second buckle plate 12 are respectively provided with arc grooves, and the two arc grooves are pieced together to form a core accommodating cavity, the full-ear core is located in the core accommodating cavity and the ear is exposed beyond the core accommodating cavity, the combined end faces of the first buckle plate 11 and the second buckle plate 12 are connected by the buckle plate connecting column 13, and the buckle plate connecting column 13 is fixed on both sides of the arc groove of the second buckle plate 12, and the first buckle plate 11 is located on both sides of the arc groove and buckle plate connecting holes are correspondingly provided, the buckle plate connecting column is inserted into the buckle plate connecting hole to buckle the first buckle plate and the second buckle plate to clamp the full-ear core, and the core clamping assembly 1 has an anti-fool design.

[0034] The preliminary shaping device includes a preliminary shaping positioning component 2 and a preliminary shaping component 3; the preliminary shaping positioning component 2 includes a preliminary shaping positioning plate 201, and the preliminary shaping positioning plate 201 is provided with a pole lug accommodating groove on the end face facing the pole lug, the pole lug accommodating groove coincides with the axis of the center hole of the winding core, and the inner diameter of the pole lug accommodating groove is larger than the diameter of the winding core, and can cover all the pole lugs exposed from the winding core clamping component 1; the preliminary shaping positioning plate 201 is provided with a plurality of prostration guide grooves 202 on the end face away from the pole lug, each prostration guide groove 202 radiates outward with the axis of the pole lug accommodating groove as the center, and the minimum distance between each prostration guide groove 202 and the axis of the pole lug accommodating groove is greater than zero, ensuring that the pole lugs in the center hole of the winding core and its surroundings will not be pressed and remain vertical; each prostration guide groove 202 is communicated with the pole lug accommodating groove, so that the preliminary shaping prostration head of the preliminary shaping component can extend into the pole lug accommodating groove to extrude the pole lug.

[0035] The end face of the initial shaping positioning plate 201 where the tab accommodating groove is provided is detachably connected to the end face where the tab of the core clamping assembly is exposed. It can be fastened by a concave-convex structure, or connected by a mortise-tenon structure, or fixed by bolts. As long as the initial shaping positioning plate 201 is assembled onto the core clamping assembly 1, the tab accommodating groove can cover the tab.

[0036] The initial shaping assembly 3 applies a pressure along the axial direction of the core to make the tab corresponding to the lodging guiding groove initially lodge towards the direction of the core central hole.

[0037] The described initial shaping assembly 3 includes an initial shaping fixed plate 31, an initial shaping moving plate 32, an initial shaping lodging head 33, and an elastic connecting member.

[0038] The initial shaping fixed plate 31 and the initial shaping moving plate 32 are connected by an elastic connecting member. The distance between the initial shaping fixed plate 31 and the initial shaping moving plate 32 is adjusted by the elastic connecting member. This distance serves as the moving space of the initial shaping moving plate 32, that is to say, the elastic space of the elastic connecting member corresponds to the lodging depth of the initial shaping tab.

[0039] The described elastic connecting member includes a guiding bolt 341, a spring 342, and an adjusting nut 343. One end of the guiding bolt 341 passes through the initial shaping moving plate 32 and is fixedly connected to the initial shaping fixed plate 31. The other end of the guiding bolt 341 is exposed from the initial shaping moving plate 32 and is threadedly connected to the adjusting nut 343. The initial shaping moving plate 32 can reciprocally move along the guiding bolt 341. The spring 342 is arranged between the initial shaping fixed plate 31 and the initial shaping moving plate 32. The deformation amount of the spring 342 is the lodging depth of the initial shaping tab. To prevent the spring from shaking or tilting, spring installation grooves can be provided on the end faces of both the initial shaping fixed plate 31 and the initial shaping moving plate 32, and the springs are symmetrically installed. The springs can also prevent metal debris from being generated due to the collision between the initial shaping moving plate and the initial shaping positioning plate. By adjusting the position of the adjusting nut on the guiding bolt, the position of the initial shaping moving plate on the guiding bolt can be changed, thereby changing the deformation amount of the spring and the movable space of the initial shaping moving plate.

[0040] The initial shaping fixed plate 31 is located on the initial shaping positioning plate 201; the initial shaping fixed plate 31 is provided with a lodging head guiding hole 311, and the lodging head guiding hole 311 corresponds to the lodging guiding groove 202; the initial shaping moving plate 32 is provided with a lodging head mounting hole 321, and the initial shaping lodging head 33 is fixedly installed at the lodging head mounting hole 321 and the working end of the initial shaping lodging head 33 passes through the lodging head mounting hole 321 and the lodging head guiding hole 311 and then extends into the lodging guiding groove 202; the initial shaping moving plate 32 bearing the axial pressure drives the initial shaping lodging head 33 to extrude the tab; after the axial pressure disappears, under the restoring force of the elastic connecting piece, the initial shaping moving plate 32 drives the initial shaping lodging head 33 to reset. The initial shaping lodging head 33 is a flat cuboid-shaped thin sheet, and all the initial shaping components are made of stainless steel material.

[0041] In the initial state, the initial shaping lodging head 33 extends into the tab accommodating groove and contacts the end of the tab. After being pressed, the initial shaping lodging head 33 extrudes the tab to make it all incline towards the core center hole direction. The size of the initial shaping lodging head 33 is slightly smaller than the lodging guiding groove 202, so that it can reciprocate along the lodging guiding groove 202 on the core axis, and the initial shaping lodging head 33 can make all the tabs corresponding to the lodging guiding groove 202 incline after being extruded once, which can avoid debris falling into the core gap during the extrusion process.

[0042] Before initial shaping, the initial shaping component is placed at the innermost side of the lodging guiding groove, that is, the initial shaping lodging head 33 extending into the lodging guiding groove 202 forms a flicking from the outside to the inside on the contacted tab during a small range of movement. Here, the outside refers to the outermost layer of the core, and the inside refers to the core center hole; the tab to be lodged can be preliminarily pressed to make it have a lodging tendency towards the core center hole direction; because the initial shaping lodging head is only slightly smaller than the lodging guiding groove, the purpose of this movement is to make the initial shaping lodging head located at the end of the lodging guiding groove 202.

[0043] After initial shaping, in order to avoid the tab rebounding and affecting the tab lodging effect, and further affecting the welding yield with the current collector plate, the tab after initial shaping is subjected to deep shaping. The deep shaping uses a deep shaping device, and the deep shaping device includes a detachable current collector plate carrier 4 and a pressing tool 5.

[0044] The detachable current collecting disc carrier 4 is provided with a current collecting disc welding groove 41, and a number of current collecting disc welding clearance holes 42 are provided in the current collecting disc welding groove 41; the current collecting disc welding clearance holes correspond one-to-one to the areas to be welded of the current collecting disc, and the current collecting disc welding clearance holes have the same shape as the welding area of the current collecting disc, both of which are fan-shaped or quasi-fan-leaf-shaped. As the welding station of the current collecting disc, the back side of the current collecting disc welding groove 41 serves as the current collecting disc assembly position. After the current collecting disc is assembled in place, the detachable current collecting disc carrier 4 is detachably connected to the winding core clamping component 1 and the current collecting disc at the current collecting disc assembly position is in contact with the pole ear; and the detachable current collecting disc carrier 4 is pressed against the winding core clamping component 1 by the pressure tool 5, and the pressure tool 5 provides pressure along the axial direction of the winding core to the detachable current collecting disc carrier to deepen the depth of the pole ear. The pressure-applying tool can be a locking bolt, that is, bolt holes are provided on the end faces of the detachable current-carrying tray carrier 4 and the first and second gusset plates. The locking bolt passes through the bolt hole of the detachable current-carrying tray carrier and then extends into the bolt holes of the first and second gusset plates. By adjusting the depth of the locking bolt extending into the first and second gusset plates, the axial force applied by the detachable current-carrying tray carrier to the tab can be changed, that is, the depth of the depth shaping can be adjusted; Figure 6 and 7 shown.

[0045] Of course, you can also use a clamp to clamp and apply pressure. Set a clamping position on the outer wall of the first gusset plate and the second gusset plate. One clamping part of the clamp clamps the detachable current-carrying disc carrier, and the other clamping part is clamped to the clamping position of the first gusset plate or the second gusset plate, providing axial pressure to the detachable current-carrying disc carrier so that it presses the tab. Figure 8 shown.

[0046] The present invention also provides a method for shaping a full-tab winding core using the full-tab shaping device of the present invention. The full-tab winding core used is formed by wrapping a diaphragm, a positive electrode sheet, and a negative electrode sheet around each other. The positive electrode sheet is an aluminum foil uniformly coated on both sides with one or more slurries such as lithium iron phosphate, lithium nickel chromium manganese oxide, and lithium nickel chromium aluminum oxide as main materials. At the same time, an empty foil area of a certain length is left in the width direction of the positive electrode sheet, which is called a positive electrode tab; similarly, the negative electrode sheet is a copper foil uniformly coated on both sides with one or more slurries such as graphite, silicon carbon, silicon oxide, etc. as main materials. At the same time, an empty foil area of a certain length is left in the width direction of the negative electrode sheet, which is called a negative electrode tab; the positive and negative electrode tabs are respectively located at the two ends of the winding core.

[0047] The steps are: S1, use the primary shaping device to perform primary shaping on the tabs of the full-tab core, so that the tabs welded to the collector plate are initially tilted toward the center hole of the core; the tabs near the center hole of the core are not tilted, that is, the tilted tabs are from the outermost layer of the core to a certain distance from the center hole of the core, which is generally 2-3 turns outside the center hole of the core; The initial shaping device includes an initial shaping positioning assembly 2 and an initial shaping assembly 3; the initial shaping positioning assembly 2 is used to cover the tab and provide a lodging guiding direction for the initial shaping assembly 3, improving the accuracy of initial shaping and reducing the operation difficulty; the initial shaping assembly 3 is used to apply a pressure in the axial direction of the core to the tab to be lodged, so that the tab is initially lodged; the initial lodging depth is 0.1-1.0 mm; the initially lodged tabs all lodge towards the direction of the core center hole, which can effectively prevent the laser light or metal chips that may be generated during the welding process from entering the core gap, reducing the risk of causing a short circuit and improving the qualification rate of core production.

[0048] The specific steps are as follows: S11, before initial shaping, use the core clamping assembly 1 to clamp the full-tab core and make the tabs of the full-tab core expose a certain length from the core clamping assembly 1; the core clamping assembly 1 clamps and tightens the wound full-tab core, and makes the tabs of the core expose from the core clamping assembly, preparing for initial shaping; before shaping, the tabs are as Figure 1 shown; S12, use the initial shaping positioning assembly 2 to position the tabs. The initial shaping positioning assembly 2 is provided with a tab receiving groove and a lodging guiding groove; the tab receiving groove covers the tabs that expose from the core clamping assembly 1; the lodging guiding groove is arranged along the radial direction of the tab receiving groove and communicates with the tab receiving groove; the shape formed by each lodging guiding groove is the same as the shape of the welding area of the current collector plate; the shape of the lodging guiding groove is a fan shape or a shape similar to a fan shape, the same as the welding area of the current collector plate; and the size of the tab receiving groove is slightly larger than the core diameter, and the depth is also greater than the length of the exposed tabs, which can cover all the tabs that expose from the core clamping assembly, and can weaken the influence of the tabs in the shaping area on the tabs that do not need to be shaped beside them during initial shaping; S13, under the guiding action of the lodging guiding groove, the initial shaping assembly 3 applies a pressure in the axial direction of the core to the tabs corresponding to the lodging guiding groove, so that the tabs initially lodge towards the direction of the core center hole. The tabs lodged after a single extrusion are the areas corresponding to the lodging guiding groove, which can avoid generating debris during the lodging process, that is, in the radial direction of the tab receiving groove, the initial shaping assembly does not need to move and extrude multiple times. The initial shaping assembly only extrudes multiple times along the axis direction of the tab receiving groove to ensure that all the tabs to be lodged are lodged. The tabs after initial shaping are as Figure 2 shown; To avoid the rebound of the tabs after initial shaping, in S2, use the depth shaping device 4 to perform depth shaping on the initially lodged tabs and weld the current collector plate. The depth shaping deepens the lodging depth of the tabs, and the lodging depth of the tabs after depth shaping is 0.2-1.0 mm.

[0049] The depth shaping device 4 includes a detachable current collecting disc carrier and a pressure tool. The detachable current collecting disc carrier is provided with a current collecting disc welding groove, and a plurality of current collecting disc welding clearance holes are provided in the current collecting disc welding groove. The current collecting disc welding clearance holes correspond to the areas to be welded of the current collecting disc one by one. The pressure tool provides the detachable current collecting disc carrier with pressure along the axial direction of the winding core to deepen the depth of the pole ear. After the depth shaping, the pole ear is as follows. Figure 3 As shown in the figure, deep shaping not only prevents tab rebound after initial shaping, which could affect welding quality, but also ensures that the tab's collapsed area includes the area where it will be welded to the collector plate, guaranteeing concentricity between the collector plate and the winding core. Furthermore, tab deep shaping and collector plate welding are performed at the same station, on a removable collector plate carrier, saving production space and improving processing efficiency.

[0050] The specific steps of depth shaping are: S21, removal of the primary shaping device; S22, place the current collecting plate on the back of the current carrying plate welding groove, install the detachable current collecting plate carrier with the current carrying plate on the winding core clamping assembly 1, and make the current carrying plate contact with the initially fallen tab; the current carrying plate is made of copper alloy, and the welding area can be 1-n fan blades or fan blade-like shapes, and the welding area depth is 0.2-1.2mm; S23, the pressure applying tool provides pressure along the axial direction of the winding core, so that the detachable collecting plate carrier squeezes the initially fallen tab to increase the falling depth of the tab; S24, welding the current collecting plate to the fallen tab at the current collecting plate welding hole, using one of the welding methods such as resistance welding, laser welding, arc welding, ultrasonic welding, etc., with one or more of point, straight line, multi-straight line, spiral line, and sine line as the welding trajectory, adjusting the welding power and welding speed according to the actual capacity of the welding equipment and welding materials, etc., to achieve the connection between the current collecting plate and the tab; S25, remove the depth shaping device and the core clamping component 1.

[0051] The positive and negative tabs of the full tab winding core are respectively installed with the above steps to perform tab shaping and current collecting plate welding.

[0052] In order to verify the welding effect of the tab and the winding core after shaping of the present invention, performance tests were carried out on an experimental group and a control group.

[0053] Experimental group: cores with deep shaping of positive and negative tabs; Control group: coil core without tab shaping; The cores of the experimental and control groups were laser welded (with a three-straight line welding trajectory). The welding effects of the two schemes were evaluated by testing the Hipot yield, the tension between the collector plate and the core tab, the residual rate of the collector plate foil, and random disassembly to check whether the diaphragm was burned or translucent.

[0054] Hipot test conditions: voltage 100V, time 1S, breakdown internal resistance requirement > 100MΩ; Tensile force is tested using a tensile testing machine: Tensile forces 1 and 2 are the tensile forces between the positive current collector plate and the tab and between the negative current collector plate and the tab respectively, requirement: > 10N (reference); Foil residue rate: After using a tensile testing machine to separate the current collector plate from the tab, the proportion of the area of the residual foil on the current collector plate to the entire welding area. Among them, foil residue rate 1 is for the positive electrode and foil residue rate 2 is for the negative electrode. The characterization method is to use a microscope to observe the current collector plate after welding, measure and mark the residual foil size and the entire weld mark size, and then calculate. The requirement is > 80%; Hipot failure disassembly verification failure rate is the statistics of disassembling the cells with Hipot display failures to check whether the separator is scalded; Random disassembly failure rate is the statistics of randomly disassembling the cells with normal Hipot test results to check the damage of the separator.

[0055]

[0056] According to the above data, it is found that: in the experiment of the fully tabbed core after shaping in the experimental group, the Hipot yield rate is 99.99%. No damage to the separator was found in the randomly disassembled cores. While for the cores in the control group that were welded without tab shaping, the Hipot yield rate is only 99.2%. After disassembly, it was confirmed that the separator was burned through. After randomly disassembling the cores with qualified Hipot test results, no damage to the separator was found.

[0057] In terms of tensile force: The tensile force values between the shaped cores and the positive and negative current collector plates are slightly larger than those in the control group, and the foil residue rates are all > 80%, meeting the process requirements.

[0058] It can be seen that using the method of the present application to shape the tabs is helpful for improving the welding yield rate and the core qualification rate.

[0059] Next, the effects of the present invention will be verified and illustrated with a specific example and several comparative examples.

[0060] Example 1: 1. Initial shaping of the negative tab of the fully tabbed core: Take a fully tabbed core with qualified winding, place it in the arc groove of the first clamping plate, adjust the length of the negative tab exposed from the first clamping plate to 0.2mm, cover the second clamping plate, and make the second clamping plate hold the core tightly with the first clamping plate.

[0061] Subsequently, the initial shaping positioning component is used to position the area that needs shaping, and the initial shaping component is used to perform initial shaping on the negative electrode ear, so that the initial shaping inversion head slides along the inversion guide groove toward the center of the winding core, and the initial shaping moving plate is pressed down twice at the end of the inversion guide groove. The spring compression amount has been adjusted to 0.2mm in advance to achieve the negative electrode ears in the initial shaping area to fall in the same direction. At this time, the depth of the negative electrode ear inversion is about 0.2mm, the length is 6.5mm, and the width is 1.5mm.

[0062] 2. Deep shaping of negative electrode tabs with full tab core: Remove the pre-shaping and positioning components and the pre-shaping assembly. Place the negative electrode current collector tray on the removable collector tray carrier, secure it to the winding core clamping assembly, and tighten the pressure tool (i.e., the screws). At this point, the negative electrode tab is approximately 0.4mm deep.

[0063] 3. Negative electrode collector welding Laser welding equipment was used to weld the negative electrode current collector and the negative electrode tab with three straight line welding trajectories at a welding power of 425 W, a welding speed of 500 ms / m, and an idle speed of 1000 ms / m.

[0064] 4. The positive electrode tab of the full-tab rolled core adopts the same shaping scheme as the negative electrode tab.

[0065] 5. Welding of positive electrode current collector.

[0066] Comparative Example 1: The difference from Example 1 is that the positive and negative tabs are not shaped and are directly welded.

[0067] Comparative Example 2: The difference from Example 1 is that the negative electrode ear is directly welded without being shaped, while the positive electrode ear is shaped before being welded.

[0068] Comparative Example 3: The difference from Example 1 is that the positive electrode ear is directly welded without being shaped, while the negative electrode ear is shaped before being welded.

[0069] Comparative Example 4: The difference from Example 1 is that a sinusoidal welding trajectory is used during welding.

[0070] Comparative Example 5: The difference from Example 1 is that the positive and negative tabs are not shaped and are directly welded using a sinusoidal welding trajectory.

[0071] Comparative Example 6: The difference from Example 1 is that the positive and negative tabs are not shaped, and spot welding is performed using non-continuous light-emitting welding equipment to connect the current collecting plate and the tabs.

[0072] Comparative Example 7: It is different from Example 1 in that: a non - continuously emitting welding device is used for spot welding to connect the current collector plate and the tab.

[0073] After the welding of the examples and each comparative example is completed, the welding reliability test is verified, and the data is as follows:

[0074] It is found from the above data that: for the fully tabbed core after tab shaping, the Hipot yield has increased after welding with various welding tracks. Among them, in Example 1, both the positive and negative tabs are shaped, and the three - straight - line welding track is adopted, and the Hipot yield reaches as high as 99.99%; Hipot yield: Example 1 > Comparative Example 7 > Comparative Example 3 > Comparative Example 4 ≈ Comparative Example 6 > Comparative Example 2 > Comparative Example 5 > Comparative Example 1.

[0075] Tensile strength: For the shaped core, due to the increased contact area between the tab and the positive and negative current collector plates, the tensile strength value is slightly larger than that without shaping. Among them, after welding with three - straight - line and sine - line, the tensile strength 1 (positive - pole tensile strength) is significantly greater than that of spot welding; the foil residue rate is > 80%, meeting the process requirements.

[0076] According to the welding effects, production efficiency and other conditions of each case, only the battery cores of Example 1, Comparative Example 1, Comparative Example 4, Comparative Example 6, and Comparative Example 7 are assembled and formed subsequently to prepare cylindrical battery cores of the same capacity and the same model, and performance tests are carried out.

[0077] In the 3C charging and 1C discharging cycle test, the test conditions are charging current 14.4A, charging cut - off voltage 4.2V, discharging current 4.8A, and discharging cut - off voltage 2.65V. As Figure 9 shown, Example 1 battery shows obvious advantages. The number of cycles at a capacity retention rate of 80%: Example 1 (686 cycles) > Comparative Example 4 (669 cycles) > Comparative Example 1 (597 cycles) > Comparative Example 7 (410 cycles) > Comparative Example 6 (293 cycles).

[0078] In the description of this specification, the descriptions referring to terms such as "one embodiment", "example", "specific example", etc. mean that the specific features, structures, materials or characteristics described in connection with that embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above - mentioned terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in a suitable manner in any one or more embodiments or examples.

[0079] The above are only the preferred specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution and inventive concept of the present invention, making equivalent substitutions or changes, should be covered within the protection scope of the present invention.

Claims

1. A full-tab ear shaping method, characterized in that, The steps are: S1, using a primary shaping device to perform primary shaping on the tabs of the full tab winding core, so that the tabs welded to the collector plate initially fall toward the center hole of the winding core; The primary shaping device comprises a primary shaping positioning assembly (2) and a primary shaping assembly (3); the primary shaping positioning assembly (2) is used to cover the pole ear and provide a falling guide for the primary shaping assembly (3); the primary shaping assembly (3) is used to apply axial pressure of the winding core to the pole ear to be fallen, so that the pole ear initially falls; S2, using a depth shaping device (4) to perform depth shaping on the initially fallen tab and weld the collector plate, wherein the depth shaping increases the fallen depth of the tab; The depth shaping device (4) comprises a detachable current collecting disc carrier and a pressure tool, wherein the detachable current collecting disc carrier is provided with a current collecting disc welding groove, and a plurality of current collecting disc welding clearance holes are provided in the current collecting disc welding groove; the current collecting disc welding clearance holes correspond one to one with the areas to be welded of the current collecting disc; and the pressure tool provides pressure along the axial direction of the winding core to the detachable current collecting disc carrier to deepen the lodging depth of the tab.

2. The all-terminal tab shaping method according to claim 1, wherein The specific steps of the initial plastic surgery are: S11, before the initial shaping, use the winding core clamping assembly (1) to clamp the full-tab winding core, and make the tabs of the full-tab winding core protrude from the winding core clamping assembly (1) by a certain length; S12, positioning the tab using a primary shaping and positioning assembly (2), wherein the primary shaping and positioning assembly (2) is provided with a tab receiving groove and a falling guide groove; the tab receiving groove is provided to cover the tab exposed from the winding core holding assembly (1); the falling guide groove is provided along the radial direction of the tab receiving groove and communicates with the tab receiving groove; S13, under the guidance of the falling guide groove, the primary shaping component (3) applies pressure along the axial direction of the winding core to the pole ear corresponding to the falling guide groove, so that the pole ear initially falls toward the center hole of the winding core.

3. The all-pole ear shaping method according to claim 2, wherein, The specific steps of depth shaping are: S21, removal of the primary shaping device; S22, placing the current collecting plate on the back of the current carrying plate welding groove, installing the detachable current collecting plate carrier for assembling the current carrying plate on the winding core clamping assembly (1), and making the current carrying plate contact with the initially fallen tab; S23, the pressure applying tool provides pressure along the axial direction of the winding core, so that the detachable collecting plate carrier squeezes the initially fallen tab to increase the falling depth of the tab; S24, welding the current-carrying disk to the inverted tab at the current-carrying disk welding clearance hole; S25, remove the depth shaping device and the core clamping assembly (1).

4. A full-tab shaping device, comprising a core holding assembly (1), characterized in that: It also includes a primary shaping device, the primary shaping device includes a primary shaping positioning component (2) and a primary shaping component (3); the primary shaping positioning component (2) is detachably connected to the winding core holding component (1), and the primary shaping positioning component (2) is provided with a tab accommodating groove and a falling guide groove; the tab accommodating groove is provided to cover the tab of the winding core holding component (1); the falling guide groove is provided along the radial direction of the tab accommodating groove and communicates with the tab accommodating groove; The initial shaping component (3) applies pressure along the axial direction of the winding core to cause the pole lug corresponding to the falling guide groove to fall initially toward the direction of the central hole of the winding core.

5. The all-terminal tab shaping device according to claim 4, wherein: It further includes a depth shaping device, and the depth shaping device includes a detachable current collector tray carrier (4) and a pressing tool (5). The detachable current collector tray carrier (4) is provided with a current collector tray assembly position. The detachable current collector tray carrier (4) is detachably connected to the core holding assembly (1) so that the current collector tray at the current collector tray assembly position contacts the tab. The detachable current collector tray carrier (4) is provided with a current collector tray welding groove (41), and a number of current collector tray welding relief holes (42) are arranged in the current collector tray welding groove (41). The current collector tray welding relief holes correspond one by one to the welding areas to be welded of the current collector tray. The pressing tool (5) provides a pressure along the axial direction of the core to deepen the lodging depth of the tab.

6. The all-tab ear shaping device according to claim 4 or 5, characterized in that: The initial shaping positioning assembly (2) includes an initial shaping positioning plate (201). The end face of the initial shaping positioning plate (201) facing the tab is provided with a tab receiving groove, and the tab receiving groove coincides with the axis of the core center hole. The end face of the initial shaping positioning plate (201) away from the tab is provided with a number of lodging guiding grooves (202). Each lodging guiding groove (202) radiates outward with the axis of the tab receiving groove as the center. The minimum distance between each lodging guiding groove (202) and the axis of the tab receiving groove is greater than zero. Each lodging guiding groove (202) communicates with the tab receiving groove.

7. The all-tab ear shaping device according to claim 6, characterized in that: The initial shaping assembly (3) includes an initial shaping fixed plate (31), an initial shaping moving plate (32), an initial shaping lodging head (33) and an elastic connecting member. The initial shaping fixed plate (31) and the initial shaping moving plate (32) are connected by the elastic connecting member, and the distance between the initial shaping fixed plate (31) and the initial shaping moving plate (32) is adjusted by the elastic connecting member. The initial shaping fixed plate (31) is located on the initial shaping positioning plate (201). The initial shaping fixed plate (31) is provided with a lodging head guiding hole (311), and the lodging head guiding hole (311) corresponds to the lodging guiding groove (202). The initial shaping moving plate (32) is provided with a lodging head mounting hole (321). The initial shaping lodging head (33) is fixedly installed at the lodging head mounting hole (321), and the working end of the initial shaping lodging head (33) passes through the lodging head mounting hole (321), the lodging head guiding hole (311) and then extends into the lodging guiding groove (202). The initial shaping moving plate (32) bearing the axial pressure drives the initial shaping lodging head (33) to squeeze the tab. After the axial pressure disappears, under the restoring force of the elastic connecting member, the initial shaping moving plate (32) drives the initial shaping lodging head (33) to reset.

8. The all-tab ear shaping device according to claim 7, wherein: The elastic connecting member includes a guiding bolt (341), a spring (342) and an adjusting nut (343). One end of the guiding bolt (341) passes through the initial shaping moving plate (32) and is fixedly connected to the initial shaping fixed plate (31). The other end of the guiding bolt (341) exposes the initial shaping moving plate (32) and is threadedly connected to the adjusting nut (343). The initial shaping moving plate (32) can reciprocate along the guiding bolt (341). The spring (342) is arranged between the initial shaping fixed plate (31) and the initial shaping moving plate (32), and the deformation amount of the spring (342) is the lodging depth of the initially shaped tab.

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