A thermal compounding coiling machine and a cell coiling method

Abstract

A kind of hot compound winding machine and cell winding method, hot compound winding machine includes: first pole piece unwinding mechanism, second pole piece unwinding mechanism, first diaphragm unwinding mechanism, second diaphragm unwinding mechanism and intermittent hot compound mechanism, traction mechanism and winding head are sequentially arranged along the conveying direction of material belt after unwinding;The intermittent hot compound mechanism is used to carry out intermittent hot compound to pole piece and diaphragm stacked together, and form the compound pole piece that hot compound area and uncompound area are sequentially arranged alternately;The traction mechanism is used to pull the compound pole piece;The winding head is provided with winding needle, for winding the compound pole piece into cell.This application uses the way of intermittent hot compound to pole piece and diaphragm, forms the compound pole piece that inner and outer layer material belt length is not identical, and positive and negative pole lug position accuracy is more easily controlled, and positive and negative pole piece alignment is better, and there is no head uncontrolled or tail swing problem of conventional winding mode, and winding alignment is better, improves winding precision.

Description

Technical Field

[0001] This invention belongs to the field of lithium battery manufacturing technology, specifically relating to a thermal composite winding machine and a winding method for lithium-ion cells. Background Technology

[0002] Square lithium-ion battery cells are mainly manufactured through two processes: winding and stacking. The winding process involves separately unwinding the positive electrode, negative electrode, and separator, then winding them together onto a winding needle to form the cell. Traditional winding processes involve separately unwinding the positive and negative electrode sheets onto the winding needle. This makes it difficult to control the position of the electrode tabs relative to the winding needle, resulting in low positional accuracy of the positive and negative electrode tabs in the produced cells. Furthermore, due to the large amount of material being wound, the beginning and end of the electrode sheets are not controlled by the alignment mechanism, leading to low alignment accuracy of the positive and negative electrode sheets. Additionally, the tension of the separator can cause the wound cells to easily form an S-shape, making it difficult to guarantee winding accuracy, which in turn affects cell quality. Moreover, since the positive and negative electrode sheets and the separator need to be fed into the winding needle separately, the auxiliary movements of the mechanism are numerous, affecting equipment production efficiency. Summary of the Invention

[0003] The purpose of this invention is to provide a thermal composite winding machine and a battery cell winding method with high winding accuracy and improved battery cell quality.

[0004] To achieve the above objectives, the present invention adopts the following technical solution:

[0005] A thermal composite winding machine includes: a first electrode unwinding mechanism, a second electrode unwinding mechanism, a first diaphragm unwinding mechanism, a second diaphragm unwinding mechanism, and an intermittent thermal composite mechanism, a traction mechanism, and a winding head arranged sequentially along the conveying direction of the unwound material strip; the intermittent thermal composite mechanism is used to intermittently thermally composite the stacked electrode sheets and diaphragms to form a composite electrode sheet with alternating thermally composited and uncomposite areas; the traction mechanism is used to traction the composite electrode sheet; the winding head is provided with winding needles for winding the composite electrode sheet into a battery cell.

[0006] As described above, the intermittent thermal bonding winding machine may optionally include a hot-pressing roller and a compensating roller arranged opposite each other, both of which can rotate around their own axes. The hot-pressing roller can press on the compensating roller, and when the pressure of the hot-pressing roller on the compensating roller reaches the thermal bonding pressure threshold, the electrode and the diaphragm are thermally bonded together. The hot-pressing roller performs actions at set time intervals, such as the pressure on the compensating roller reaching the thermal bonding pressure threshold, the pressure on the compensating roller being less than the thermal bonding pressure threshold, and the pressure on the compensating roller reaching the thermal bonding pressure threshold, thereby realizing the intermittent thermal bonding of the electrode and the diaphragm.

[0007] As described above in the thermal composite winding machine, optionally, the hot pressure roller can be moved to approach and press against the compensation roller, or move away from the compensation roller.

[0008] The thermal composite winding machine described above may optionally include a thermal pressure control mechanism for controlling the pressure of the thermal pressure roller on the compensating roller.

[0009] As described above, in the thermal composite winding machine, optionally, both the hot pressing roller and the compensating roller are active rollers. The hot pressing roller is driven to rotate by a rotary drive motor. The output shaft of the rotary drive motor is connected to a transmission shaft through a coupling. The transmission shaft is connected to the rotating shaft of the hot pressing roller through a one-way bearing. The rotational speed of the hot pressing roller is lower than that of the compensating roller.

[0010] As described above, in the thermal composite winding machine, optionally, the traction mechanism includes a first traction roller and a second traction roller arranged opposite to each other. Both the first traction roller and the second traction roller can rotate around their own axes. The first traction roller is the driving roller, and the second traction roller is the driven roller. The second traction roller includes a main shaft, a roller frame disposed on the main shaft, a roller shaft disposed on the roller frame, and rollers disposed on the roller shaft. The roller frame can rotate around the axis of the main shaft. The roller shaft is located on the periphery of the main shaft. Multiple roller shafts are arranged circumferentially at intervals. The rollers can rotate around the axis of the roller shaft. There is a gap between adjacent rollers in the circumferential direction. When the second traction roller presses on the first traction roller, at least one roller presses on the first traction roller.

[0011] As described above, the thermal composite winding machine may optionally have several guide rollers arranged on the material strip movement path between the traction mechanism and the winding head. The guide rollers include patterned rollers, which include a main roller shaft and multiple rotating roller shafts spaced circumferentially around the main roller shaft. Rotating roller shaft supports are provided at both ends of the main roller shaft, and the rotating roller shafts are rotatable around the main roller shaft.

[0012] The present invention also provides a cell winding method using the aforementioned thermal composite winding machine, comprising the following steps:

[0013] The first electrode unwinding mechanism, the second electrode unwinding mechanism, the first diaphragm unwinding mechanism, and the second diaphragm unwinding mechanism respectively unwind the first electrode, the second electrode, the first diaphragm, and the second diaphragm. The first electrode unwinding mechanism includes a feeding clamp and an electrode cutter arranged in sequence, which feed the first electrode by cutting and feeding it. The second electrode unwinding mechanism includes a cutting, separating, and adhesive-applying mechanism, which cuts the second electrode and then connects the cut strips together with adhesive tape. When the second electrode passes through the cutting, separating, and adhesive-applying mechanism, it is cut and connected with adhesive tape at the cutting, separating, and adhesive-applying mechanism to form a sheet with discontinuous electrode sheets and continuous strips.

[0014] The first electrode, the second electrode, the first diaphragm, and the second diaphragm are stacked in the order of first electrode, first diaphragm, second electrode, and second diaphragm and intermittently thermally bonded at the intermittent thermal bonding mechanism to obtain a composite electrode. During thermal bonding, the first electrode is located on the outermost side, and the thermal bonding results in a composite electrode with a wavy surface on one side. The length of the first electrode is greater than the length of the second electrode, the first diaphragm, and the second diaphragm.

[0015] The traction mechanism pulls the composite electrode sheet;

[0016] The composite electrode is wound into a battery cell at the winding head.

[0017] As described above in the cell winding method, optionally, when the intermittent thermal bonding mechanism performs thermal bonding on the electrode and the separator,

[0018] The unwound electrode and diaphragm are wound onto the compensating roller, with the first electrode located on the outer side;

[0019] The hot pressing roller and the compensation roller rotate around their respective axes at a set speed, and the electrode and diaphragm are carried between the hot pressing roller and the compensation roller;

[0020] The hot press roller is controlled to approach and press against the compensation roller to thermally bond the electrode and the separator. Then, the hot press roller is controlled to move away from the compensation roller, and the electrode and the separator cannot be bonded together. The compensation roller rotates to drive the composite sheet obtained after hot pressing backward. After traveling a certain distance, the hot press roller is controlled to approach and press against the compensation roller again to thermally bond the electrode and the separator again. Then, the hot press roller is controlled to move away from the compensation roller, and the above process is repeated to perform intermittent thermal bonding of the electrode and the separator.

[0021] Alternatively, the unwound electrode and diaphragm are wound onto the compensating roller, with the first electrode located on the outer side;

[0022] The hot pressing roller and the compensation roller rotate around their respective axes at a set speed. The hot pressing roller presses on the compensation roller, and the electrode sheet and diaphragm are carried between the hot pressing roller and the compensation roller.

[0023] The pressure of the hot pressing roller on the compensation roller is controlled so that the pressure of the hot pressing roller on the compensation roller reaches the thermal bonding pressure threshold to thermally bond the electrode and the separator. Then the pressure of the hot pressing roller on the compensation roller is controlled so that the pressure of the hot pressing roller on the compensation roller is less than the thermal bonding pressure threshold, so that the electrode and the separator cannot be bonded together.

[0024] The rotating compensating roller drives the composite sheet obtained after hot pressing backward. After traveling a certain distance, the pressure of the hot pressing roller on the compensating roller is controlled again to reach the hot composite pressure threshold to perform hot composite of the electrode and the separator. Then, the pressure of the hot pressing roller on the compensating roller is controlled to be less than the hot composite pressure threshold, and the above process is repeated to perform hot composite of the electrode and the separator.

[0025] As described above, in the cell winding method, optionally, the composite electrode sheet is carried between the first traction roller and the second traction roller, the first electrode sheet and the second traction roller are opposite each other, and when the second traction roller presses on the first traction roller, the roller is always pressing on the first traction roller and in contact with the first electrode sheet.

[0026] And / or, when the composite electrode passes around the roller, the side where the first electrode is located comes into contact with the rotating roller shaft.

[0027] As can be seen from the above technical solutions, the thermal composite winding machine of the present invention is equipped with an intermittent thermal composite mechanism, which can intermittently thermally composite the electrode sheet and the separator at a set time interval to form a composite electrode sheet with inconsistent lengths of inner and outer layer strips. The length difference between the inner and outer layer electrode sheets is consistent with the length difference between the inner and outer layers required for winding by the winding needle, thus solving the problem of wrinkling of the inner layer strip when the composite electrode sheet is wound into a battery cell. Furthermore, the positional accuracy of the positive and negative electrode tabs of the formed composite electrode sheet is easier to control, and the alignment of the positive and negative electrode sheets is better, improving the winding accuracy. Using a winding head with three winding needle stations, the composite electrode sheet can be continuously wound, completing actions such as changing stations, clamping the composite electrode sheet with the winding needle, cutting the composite electrode sheet, and then starting a new battery cell winding. The winding is uninterrupted, resulting in higher efficiency. Because the composite electrode sheet is an integral structure, it does not have the problems of uncontrolled head or tail swinging that exist in conventional winding methods; the winding alignment is better, and during the winding process, the tension is mainly borne by the electrode sheet, while the separator has virtually no tension, which can solve the problem of S-shaped cells in conventional winding methods. Attached Figure Description

[0028] To more clearly illustrate the embodiments of the present invention, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0029] Figure 1 This is a schematic diagram of the structure of the thermal composite winding machine according to an embodiment of the present invention;

[0030] Figure 2 This is a schematic diagram of the electrode sheet after being cut, separated, and glued according to an embodiment of the present invention;

[0031] Figure 3 This is a schematic diagram of the composite electrode after thermal bonding of the electrode sheet and the diaphragm according to an embodiment of the present invention;

[0032] Figure 4 This is a schematic diagram of the structure of the hot pressing roller and the compensation roller in an embodiment of the present invention;

[0033] Figure 5 This is a schematic diagram of the traction mechanism according to an embodiment of the present invention;

[0034] Figure 6 This is a schematic diagram of the structure of the second traction roller in an embodiment of the present invention;

[0035] Figure 7 This is a schematic diagram of the roller structure according to an embodiment of the present invention.

[0036] The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings. Detailed Implementation

[0037] The present invention will now be described in detail with reference to the accompanying drawings. In the detailed description of the embodiments of the present invention, for ease of explanation, the drawings illustrating the device structure will be partially enlarged without adhering to the general scale. Furthermore, the schematic diagrams are merely examples and should not be construed as limiting the scope of protection of the present invention. It should be noted that the drawings are in a simplified form and use non-precise scales, solely for the purpose of conveniently and clearly illustrating the embodiments of the present invention. Additionally, in the description of this application, terms such as "first" and "second" are used only to distinguish descriptions and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Terms such as "positive," "negative," "bottom," "upper," and "lower" indicate orientation or positional relationships based on the orientation or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention.

[0038] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can also refer to the internal connection of two components; and they can refer to a wireless connection or a wired connection. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0039] like Figure 1 As shown, the thermal bonding winding machine of this embodiment includes a first electrode unwinding mechanism 1, a second electrode unwinding mechanism 2, a first diaphragm unwinding mechanism 3, a second diaphragm unwinding mechanism 4, an intermittent thermal bonding mechanism 5, a traction mechanism 6, and a winding head 7. The electrode / diaphragm unwinding mechanism is used to unwind the electrode / diaphragm strip, and the traction mechanism 6 is used to traction and move the strip, causing it to move to the intermittent thermal bonding mechanism 5 for thermal bonding, and to the winding head 7 for winding. The first electrode and the second electrode have opposite polarities; this embodiment uses the first electrode as a positive electrode and the second electrode as a negative electrode as an example for explanation.

[0040] The first electrode unwinding mechanism 1 includes a first roll mounting shaft (not shown), a first electrode tension control mechanism 1-1, a feeding clamp 1-2, an electrode cutter 1-3, and a first electrode alignment mechanism 1-4. The positive electrode roll 101 is mounted on the first roll mounting shaft, which can rotate around its own axis to achieve unwinding of the strip. The first electrode tension control mechanism 1-1, the feeding clamp 1-2, the electrode cutter 1-3, and the first electrode alignment mechanism 1-4 are arranged sequentially along the moving direction of the first electrode. The first electrode tension control mechanism 1-1 controls the tension of the electrode during the traction and conveying process; the feeding clamp 1-2 feeds the electrode forward; the electrode cutter 1-3 cuts the first electrode; and the first electrode alignment mechanism 1-4 aligns the electrode. The alignment mechanism typically includes an alignment pressure roller and an alignment roller. The tension control mechanism and the correction mechanism of the present invention both adopt the conventional tension control structure and correction structure on existing winding machines. The present invention does not improve the tension control mechanism and the correction mechanism, and will not be described in detail here.

[0041] The second electrode unwinding mechanism 2 includes a second roll mounting shaft (not shown), a cutting, separating, and adhesive-applying mechanism 2-1, a second electrode tension control mechanism 2-2, and a first oscillating correction mechanism 2-3. The negative electrode roll 102 is mounted on the second roll mounting shaft, which can rotate around its own axis. The cutting, separating, and adhesive-applying mechanism 2-1 is used to cut the unwound strip and then connect the cut strips together with adhesive tape. The adhesive-applied electrode is shown below. Figure 2As shown. After the negative electrode 102 moves to the position of the cutting, separating, and adhesive-applying mechanism 2-1, the cutter (not shown) of the cutting, separating, and adhesive-applying mechanism 2-1 first cuts the negative electrode 102, and then the adhesive-applying mechanism (such as an adhesive roller, adhesive-applying robot, etc.) applies adhesive tape to the cut point, reconnecting the cut negative electrode 102 together. The cutting position of the electrode is the length of electrode required to wind one battery cell, and the length of the strip obtained after cutting the material roll is the length required to wind one battery cell.

[0042] The first diaphragm unwinding mechanism 3 and the second diaphragm unwinding mechanism 4 have the same structure, both including a diaphragm roll mounting shaft (not shown) and a diaphragm tension control mechanism (not labeled). The diaphragm roll is mounted on the diaphragm roll mounting shaft, and the diaphragm roll is unwound when the diaphragm roll mounting shaft rotates around its own axis. The first diaphragm roll 103 is mounted on the diaphragm roll mounting shaft of the first diaphragm unwinding mechanism 3, and the second diaphragm roll 104 is mounted on the diaphragm roll mounting shaft of the first diaphragm unwinding mechanism 4.

[0043] After the material strip (electrode / diaphragm) is unwound, an intermittent thermal bonding mechanism 5, a traction mechanism 6, and a winding head 7 are sequentially arranged in the conveying direction of the material strip. Before the first and second electrodes are fed into the intermittent thermal bonding mechanism 5 for thermal bonding, a preheating mechanism can be set up to preheat the first and second electrodes. Figure 1 The obliquely filled area in the text represents the preheating station for the first and second electrodes, where the first and second electrodes are preheated.

[0044] The first and second electrodes and the first and second diaphragms are stacked in the order of first electrode, first diaphragm, second electrode, second diaphragm and then fed together into the intermittent thermal bonding mechanism 5 for thermal bonding. The intermittent thermal bonding mechanism 5 is used to perform intermittent thermal bonding operations on the electrodes and diaphragms. The electrodes obtained by intermittent thermal bonding have thermally bonded areas and unbonded areas. In the thermally bonded areas, the electrodes and diaphragms are bonded together, and in the unbonded areas, the electrodes and diaphragms are not bonded together. The thermally bonded areas and unbonded areas are alternately arranged, with one thermally bonded area followed by an unbonded area, and vice versa, and this process is repeated.

[0045] like Figure 4As shown, the intermittent thermal compounding mechanism 5 of this embodiment includes a hot press roller 5-1 and a compensating roller 5-2 arranged opposite to each other. Both the hot press roller 5-1 and the compensating roller 5-2 can rotate around their own axes. The hot press roller 5-1 rotates around its own axis under the control of the hot press roller rotation drive unit 5-3, and the compensating roller 5-2 rotates around its own axis under the control of the compensating roller rotation drive unit (not shown). Both the hot press roller 5-1 and the compensating roller 5-2 are equipped with heating devices. In this embodiment, the heating device is a heating rod 5-4 arranged along the axis of the hot press roller / compensating roller. The heating rod 5-4 can rotate together with either the hot press roller 5-1 or the compensating roller 5-2, thereby improving heating efficiency. The heating rod 5-4 is connected to an external power source through an electric slip ring 5-5 located at the ends of the heating roller and the compensating roller.

[0046] In this embodiment, the hot-pressing roller 5-1 can approach or move away from the compensating roller 5-2 under the control of the hot-pressing roller translation drive unit (not shown). When the hot-pressing roller 5-1 approaches and presses against the compensating roller 5-2, the electrode / diaphragm located between the hot-pressing roller 5-1 and the compensating roller 5-2 can be thermally bonded. When the hot-pressing roller 5-1 moves away from the compensating roller 5-2, the electrode / diaphragm located between the hot-pressing roller 5-1 and the compensating roller 5-2 is not thermally bonded. The hot-pressing roller 5-1 presses against the compensating roller 5-2 at set time intervals, thereby intermittently thermally bonding the electrode and the diaphragm together.

[0047] This embodiment uses a movable hot-press roller to intermittently press against a compensating roller to achieve intermittent thermal bonding. In other embodiments, intermittent thermal bonding can also be achieved by adjusting the pressure of the hot-press roller on the compensating roller through a hot-press roller pressure control mechanism. For example, the hot-press roller does not move but remains pressed against the compensating roller. The hot-press roller pressure control mechanism controls the pressure of the hot-press roller on the compensating roller, adjusting the pressure according to a set time to reach or fall below the thermal bonding pressure threshold. When the pressure of the hot-press roller on the compensating roller is less than the thermal bonding pressure threshold, the electrode and the separator cannot bond. When the pressure of the hot-press roller on the compensating roller is greater than the thermal bonding pressure threshold, the electrode and the separator bond together. The hot-press roller pressure control mechanism can be a pressure cylinder, controlling the pressure of the hot-press roller on the compensating roller to be sufficiently high to thermally bond the electrode and the separator together.

[0048] During hot-pressing, the hot-pressing roller presses against the compensating roller. If the surface linear velocities of the two rollers are inconsistent, it can damage the electrode sandwiched between them. If the hot-pressing roller is a driven roller, meaning it doesn't have its own rotational drive unit but rotates with the compensating roller, it will be driven to rotate by the compensating roller when it contacts it. When the hot-pressing roller leaves the compensating roller, its rotational speed will decrease significantly, resulting in a large difference between the surface linear velocities of the hot-pressing roller and the compensating roller. When the hot-pressing roller presses against the compensating roller again, this significant difference in surface linear velocities will damage the electrode. However, if the hot-pressing roller and the compensating roller are driven by an independent rotational drive unit, compared to a driven roller structure, the hot-pressing roller, being driven by the rotational drive unit, can rotate at a set speed, more closely approximating the surface linear velocity of the compensating roller. This reduces the damage to the electrode caused by inconsistent surface linear velocities to some extent. However, the rotation direction of the hot pressing roller may be affected when it comes into contact with the compensation roller, causing the surface linear velocity to change (become faster or slower). As a result, it is still difficult for the surface linear velocity of the hot pressing roller to keep in line with the surface linear velocity of the compensation roller, which may also damage the electrode sheet.

[0049] To avoid damage to the electrode due to inconsistent surface linear velocities of the hot pressing roller and the compensation roller, in this embodiment, the hot pressing roller 5-1 is preferably driven by a one-way bearing 5-6. The rotating shaft of the hot pressing roller 5-1 is connected to the output shaft of the hot pressing roller rotation drive unit 5-3 through a transmission shaft 5-7. That is, the output shaft of the hot pressing roller rotation drive unit 5-3 is connected to the transmission shaft 5-7 through a coupling, and the transmission shaft 5-7 is then connected to the rotating shaft of the hot pressing roller 5-1 through a one-way bearing 5-6. In this one-way bearing connection drive method, the hot pressing roller rotation drive unit 5-3 drives the hot pressing roller 5-1 to rotate. The hot pressing roller 5-1 can only rotate in one direction. The speed of the hot pressing roller 5-1 is set slightly lower than the speed of the compensation roller 5-2, such as 1-2% lower than the speed of the compensation roller. When the hot pressing roller 5-1 and the compensation roller 5-2 come into contact, under the action of the one-way bearing 5-6, the speed of the hot pressing roller 5-1 will be increased by the compensation roller 5-2, so that it is consistent with the surface linear velocity of the compensation roller 5-2. This achieves the effect of avoiding damage to the electrode due to inconsistent surface linear velocities. That is, by using the one-way bearing and making the surface linear velocity of the hot pressing roller 5-1 close to and less than the surface linear velocity of the compensation roller 5-2, when the hot pressing roller 5-1 presses against the compensation roller 5-2, the electrode will not be damaged due to the inconsistent surface linear velocities of the two rollers.

[0050] The steps for electrode / diaphragm thermal bonding in the intermittent thermal bonding mechanism of this embodiment are as follows:

[0051] During thermal bonding, the unwound electrode and diaphragm are wound on the compensating roller 5-2. During winding, the first electrode 101 is located on the outermost side, that is, along the radial direction of the compensating roller 5-2 from the outside to the inside, the first electrode 101, the first diaphragm 103, the second electrode 102 and the second diaphragm 104 are respectively.

[0052] Both the hot pressing roller 5-1 and the compensating roller 5-2 rotate around their respective axes at their respective set speeds, and the electrode sheet and diaphragm are conveyed between the hot pressing roller 5-1 and the compensating roller 5-2.

[0053] The hot press roller translation drive mechanism controls the hot press roller 5-1 to approach and press against the compensation roller 5-2 to thermally bond the electrode and the diaphragm.

[0054] After hot pressing is completed, the hot pressing roller translation drive mechanism controls the hot pressing roller 5-1 to move backward and away from the compensation roller 5-2. The compensation roller 5-2 rotates to drive the composite electrode sheet obtained after hot pressing backward. The electrode sheet and the separator continue to move backward. After moving a certain distance, the hot pressing roller translation drive mechanism controls the hot pressing roller 5-1 to approach and press against the compensation roller 5-2, and the electrode sheet and the separator are hot-pressed again. Then the hot pressing roller 5-1 moves away from the compensation roller 5-2. The above process is repeated to perform intermittent hot pressing of the electrode sheet and the separator.

[0055] In this embodiment, the intermittent thermal bonding mechanism 5 achieves intermittent thermal bonding by controlling the hot pressing roller to perform actions such as pressing the compensation roller at set time intervals, making the pressure on the compensation roller reach the thermal bonding pressure threshold, separating from the compensation roller (the pressure on the compensation roller is less than the thermal bonding pressure threshold), pressing the compensation roller again, and making the pressure on the compensation roller reach the thermal bonding pressure threshold. When the hot pressing roller and the compensation roller separate, the electrode and the diaphragm are not bonded together, and the first electrode 101 is located on the outermost side. Figure 3 As shown, the length of the first electrode 101 in the unheated composite zone is greater than the length of the other strips (second electrode, first / second separator), which achieves compensation of the length of the inner and outer strips. Thus, when the composite electrode is wound by the winding needle, the phenomenon of wrinkling of the inner electrode of the cell caused by the uniform length of the inner and outer strips can be avoided, thereby improving the quality of the cell.

[0056] like Figure 5 As shown, the traction mechanism 6 in this embodiment includes a first traction roller 6-1 and a second traction roller 6-2 arranged opposite to each other. Both the first traction roller 6-1 and the second traction roller 6-2 can rotate about their own axes. The axes of the first traction roller 6-1 and the second traction roller 6-2 are parallel, the first traction roller 6-1 is the driving roller, and the second traction roller 6-2 is the driven roller.

[0057] like Figure 6As shown, the second traction roller 6-2 in this embodiment includes a main shaft 6-21, a roller frame 6-22, a roller 6-23, and a roller shaft 6-24. The roller frame 6-22 is disposed at both ends of the main shaft 6-21. In this embodiment, the roller frame 6-22 is mounted on the main shaft 6-21 via bearings (not shown), allowing the roller frame 6-22 to rotate around the axis of the main shaft 6-21. The roller 6-23 is rotatably mounted on the roller frame 6-22 via the roller shaft 6-24. In this embodiment, roller shaft fixing holes (not labeled) are provided on the roller frame 6-22. Both ends of the roller shaft 6-24 are disposed in the roller shaft fixing holes, and the roller 6-23 is mounted on the roller shaft 6-24 via bearings (not shown), thereby being mounted on the roller frame 6-22. In this embodiment, the roller frame can rotate around the main shaft. In other embodiments, the roller frame can be fixed relative to the main shaft, and the main shaft can rotate around its own axis. As long as the roller frame can rotate around the axis of the main shaft, it is acceptable.

[0058] Multiple rollers 6-23 are arranged on the roller frame 6-22, with the rollers 6-23 evenly spaced circumferentially and located around the main shaft 6-21. Each roller 6-23 is mounted on the roller frame 6-22 via its respective roller shaft 6-24. In this embodiment, the roller frame 6-22 has six spaced rollers 6-23. When the roller frame 6-22 rotates around the axis of the main shaft 6-21, the rollers 6-23 can also rotate around the axis of the roller shaft 6-24.

[0059] When the traction mechanism 6 performs traction, the composite electrode sheet travels between the first traction roller 6-1 and the second traction roller 6-2. The first electrode sheet 101 in the composite electrode sheet is opposite to the second traction roller 6-2. When the second traction roller 6-2 presses on the first traction roller 6-1, a roller 6-23 is always pressing on the first traction roller 6-1 and in contact with the first electrode sheet 101. The friction generated between the first traction roller 6-1 and the second traction roller 6-2 (roller 6-23) when the first traction roller 6-1 rotates causes the roller frame 6-22 to roll and come into contact with the first traction roller 6-1 (composite electrode sheet). The contact roller 6-23 also rolls; since the second traction roller 6-2 has multiple rollers 6-23 arranged circumferentially, the rollers 6-23 arranged circumferentially alternately press on the first traction roller 6-1. Under the traction of the rollers 6-23 and the first traction roller 6-1, the composite electrode sheet can be driven forward, and the spaced rollers 6-23 will not squeeze the wavy side of the composite electrode sheet (the side where the first electrode sheet is located), which can effectively prevent the wavy first electrode sheet on the outside of the composite electrode sheet from wrinkling, thus improving both the cell quality and the winding efficiency.

[0060] A tension control device 8 and a second oscillating correction mechanism 9 are sequentially arranged between the traction mechanism 6 and the winding head 7. A guide roller is provided between the traction mechanism 6 and the winding head 7; specifically, a patterned roller 10 is provided as a guide roller between the intermittent thermal compounding mechanism 5 and the traction mechanism 6, and between the traction mechanism 6 and the second oscillating correction mechanism 9. Figure 7 As shown, the patterned roller 10 of this embodiment includes a main roller shaft 10-1 and a plurality of rotating roller shafts 10-2 evenly distributed around the main roller shaft 10-1 at circumferential intervals. In this embodiment, rotating roller shaft supports 10-3 are provided at both ends of the main roller shaft 10-1, and the rotating roller shafts 10-2 are mounted on the rotating roller shaft supports 10-3. The rotating roller shaft supports 10-3 can rotate around the main roller shaft 10-1 via bearings. In addition to the patterned roller, conventional guide rollers are also used.

[0061] In this embodiment, multiple rotating rollers 10-2 arranged circumferentially around the main roller 10-1 are arranged, with a preset distance between any two adjacent rotating rollers 10-2. When the rotating roller support 10-3 rotates relative to the main roller 10-1, the rotating rollers 10-2 on the rotating roller support 10-3 can rotate along with it and convey the composite electrode sheet. The preset distance between the rotating rollers 10-2 forms a clearance space, allowing the wavy part of the composite electrode sheet to be temporarily placed within this clearance space during conveying (i.e., the side of the first electrode sheet of the composite electrode sheet is in contact with the rotating roller), thereby preventing the wavy part from being squeezed during conveying, which could cause wrinkles or creases in the composite electrode sheet and affect the quality of the battery cell. In addition, this embodiment uses a patterned roller structure to avoid wrinkles or creases in the composite electrode sheet during conveying, thus accelerating the conveying speed of the composite electrode sheet and improving the winding efficiency of the battery cell.

[0062] In this embodiment, the winding head 7 is provided with three winding needles 7-1 arranged at circumferential intervals, forming three workstations: winding workstation A, adhesive application workstation B, and unloading workstation C. The winding needles 7-1 can be clamping roller type winding needles or vacuum winding needles. The winding needles 7-1 at winding workstation A are used to wind the composite electrode sheet into a battery cell; the winding needles 7-1 at adhesive application workstation B cooperate with the finishing pressure roller mechanism 10 and the final adhesive application roller mechanism 11 to achieve the finishing adhesive application of the battery cell; the winding needles 7-1 at unloading workstation C cooperate with the unloading robot and other unloading mechanisms to achieve the unloading of the battery cell. A diaphragm tracking and cutting mechanism 12 is provided between winding workstation A and adhesive application workstation B to cut the diaphragm.

[0063] The cell winding method of the present invention is described below:

[0064] The first electrode unwinding mechanism 1, the second electrode unwinding mechanism 2, the first diaphragm unwinding mechanism 3, and the second diaphragm unwinding mechanism 4 respectively unwind the first electrode, the second electrode, the first diaphragm, and the second diaphragm. The first electrode, the second electrode, the first diaphragm, and the second diaphragm are stacked in the order of first electrode, first diaphragm, second electrode, and second diaphragm. When the second electrode 102 passes through the cutting, separating, and adhesive-applying mechanism 2-1, it is cut and adhesive-applying at the cutting, separating, and adhesive-applying mechanism 2-1 to form a sheet with discontinuous electrode sheets and continuous material strip. The sheet feeding clamp 1-2 and the electrode cutter 1-3 follow the first electrode sheet to ensure that the second electrode sheet and the diaphragm continuously travel without interruption at the thermal bonding station, thereby improving the efficiency of intermittent thermal bonding.

[0065] The first electrode 101, the second electrode 102, the first diaphragm 103, and the second diaphragm 104 are thermally bonded at the intermittent thermal bonding mechanism 5 in the order of first electrode 101, first diaphragm 103, second electrode 102, and second diaphragm 104 to obtain a composite electrode. The hot pressure roller 5-1 and the compensation roller 5-2 of the intermittent thermal bonding mechanism 5 thermally bond the first electrode 101, the second electrode 102, the first diaphragm 103, and the second diaphragm 104 at a set time interval. During thermal bonding, the first electrode 101 is located on the outermost side of the compensation roller 5-2. The thermal bonding results in a composite electrode with a wavy surface on one side (the side surface where the first electrode is located). The length of the wavy strip (the first electrode) is greater than the length of the other layers of strip.

[0066] The traction mechanism 6 pulls the composite electrode sheet. The hot pressing roller adopts a flower roller structure to prevent the composite electrode sheet from wrinkling.

[0067] The composite electrode sheet is wound at the winding head 7 by the winding needle 7-1 of the winding station A. The diaphragm cutting mechanism 12 cuts the composite electrode sheet. Under the condition of continuous winding, it is transferred to the adhesive application station B for final adhesive application. At the same time, the winding station A starts to wind a new battery cell, and the unloading station C unloads the battery cell.

[0068] In another embodiment, when the hot press roller does not move but remains pressed against the compensation roller, the pressure of the hot press roller on the compensation roller is controlled by the hot press roller pressure control mechanism. This adjusts the pressure of the hot press roller on the compensation roller to reach the thermal bonding pressure threshold, or to perform thermal bonding when the pressure is less than the thermal bonding pressure threshold. The thermal bonding steps of this intermittent thermal bonding mechanism are as follows:

[0069] After unwinding, the electrode sheet and diaphragm are wound on the compensating roller and run on the belt. During winding, the first electrode sheet is located on the outermost side, that is, along the radial direction of the compensating roller, from the outside to the inside, the first electrode sheet, the first diaphragm, the second electrode sheet and the second diaphragm are in sequence.

[0070] Both the hot pressing roller and the compensation roller rotate around their respective axes at their respective set speeds. The hot pressing roller presses on the compensation roller, and the electrode sheet and diaphragm are carried between the hot pressing roller and the compensation roller. When the compensation roller rotates, it drives the hot-pressed composite electrode sheet to be pushed backward as a whole.

[0071] During the conveyor belt operation, the hot press roller pressure control mechanism adjusts the pressure of the hot press roller on the compensating roller so that the pressure of the hot press roller on the compensating roller reaches the thermal bonding pressure threshold, thus bonding the electrode and the diaphragm together. After the thermal bonding is completed, the hot press roller pressure control mechanism adjusts the pressure of the hot press roller on the compensating roller so that the pressure of the hot press roller on the compensating roller is less than the thermal bonding pressure threshold. At this time, due to the low pressure, the electrode and the diaphragm located between the hot press roller and the compensating roller cannot be bonded together.

[0072] The rotation of the compensating roller drives the composite electrode sheet obtained after hot pressing backward. After the composite electrode sheet travels backward for a certain distance, the hot pressing roller pressure control mechanism adjusts the pressure of the hot pressing roller on the compensating roller to reach the hot bonding pressure threshold, so as to perform hot bonding of the electrode sheet and the diaphragm. Then, the pressure of the hot pressing roller on the compensating roller is adjusted to be less than the hot bonding pressure threshold, and the above process is repeated to perform hot bonding of the electrode sheet and the diaphragm.

[0073] This embodiment's intermittent thermal bonding mechanism achieves intermittent thermal bonding by controlling the hot press roller to perform actions at set time intervals: the pressure on the compensation roller reaches a thermal bonding pressure threshold, the pressure on the compensation roller is less than the thermal bonding pressure threshold, and the pressure on the compensation roller reaches the thermal bonding pressure threshold again. When the pressure on the compensation roller is high, the composite electrode and the single electrode are thermally bonded; when the pressure on the compensation roller is low, the composite electrode and the single electrode cannot be bonded. The duration for which the pressure on the compensation roller is less than the thermal bonding pressure threshold can be set to the duration of a 180° rotation of the compensation roller. During this duration, the single electrode and the composite electrode pass through the compensation roller, but cannot be bonded due to insufficient pressure, thus achieving compensation for the length of the inner and outer electrode layers.

[0074] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A thermal composite winding machine, characterized in that, include: The first electrode unwinding mechanism, the second electrode unwinding mechanism, the first diaphragm unwinding mechanism, the second diaphragm unwinding mechanism, and the intermittent thermal bonding mechanism, the traction mechanism, and the winding head are arranged sequentially along the conveying direction of the unwound material strip. The intermittent thermal bonding mechanism is used to intermittently thermally bond the stacked electrode sheets and diaphragms to form a composite electrode sheet with alternating thermally bonded and unbonded zones. The traction mechanism is used to pull the composite electrode sheet; The winding head is equipped with winding needles for winding the composite electrode sheet into a battery cell; The intermittent thermal composite mechanism includes a hot pressing roller and a compensation roller arranged opposite to each other, and both the compensation roller and the hot pressing roller can rotate around their own axis; The hot press roller can press on the compensation roller. When the pressure of the hot press roller on the compensation roller reaches the thermal bonding pressure threshold, the electrode and the diaphragm are thermally bonded together. The hot press roller performs the action of pressing on the compensation roller to reach the thermal bonding pressure threshold - pressing on the compensation roller to be less than the thermal bonding pressure threshold - pressing on the compensation roller to reach the thermal bonding pressure threshold at a set time interval, thereby realizing the intermittent thermal bonding of the electrode and the diaphragm. During thermal bonding, the unwound electrode and diaphragm are wound onto the compensating roller. During winding, the first electrode is located on the outermost side. Along the radial direction of the compensating roller, from the outside to the inside, the first electrode, the first diaphragm, the second electrode, and the second diaphragm are arranged in sequence. In the non-thermal bonding area, the length of the first electrode is greater than the lengths of the second electrode, the first diaphragm, and the second diaphragm.

2. The thermal composite winding machine as described in claim 1, characterized in that: The hot press roller can be moved to move closer to and press against the compensation roller, or away from the compensation roller.

3. The thermal composite winding machine as described in claim 1, characterized in that: It also includes a hot press roller pressure control mechanism for controlling the pressure of the hot press roller on the compensation roller.

4. The thermal composite winding machine as described in claim 1, characterized in that: Both the hot press roller and the compensation roller are active rollers. The hot press roller is driven to rotate by a rotary drive motor. The output shaft of the rotary drive motor is connected to a transmission shaft through a coupling. The transmission shaft is connected to the rotating shaft of the hot press roller through a one-way bearing. The rotational speed of the hot press roller is lower than that of the compensation roller.

5. The thermal composite winding machine as described in claim 1, characterized in that: The traction mechanism includes a first traction roller and a second traction roller arranged opposite to each other. Both the first traction roller and the second traction roller can rotate around their own axis. The first traction roller is the driving roller, and the second traction roller is the driven roller. The second traction roller includes a main shaft, a roller frame disposed on the main shaft, a roller shaft disposed on the roller frame, and a roller disposed on the roller shaft; The roller frame is rotatable about the axis of the main shaft. The roller shaft is located on the periphery of the main shaft. Multiple roller shafts are arranged circumferentially at intervals. The rollers are rotatable about the axis of the roller shaft. There is a gap between adjacent rollers in the circumferential direction. When the second traction roller presses on the first traction roller, at least one roller is pressing on the first traction roller.

6. The thermal composite winding machine as described in claim 1, characterized in that: A number of guide rollers are provided on the material belt movement path between the traction mechanism and the winding head. The guide rollers include patterned rollers, which include a main roller shaft and a number of rotating roller shafts arranged circumferentially around the main roller shaft. The main roller shaft is provided with rotating roller shaft supports at both ends. The rotating roller shaft supports can rotate around the main roller shaft, and the rotating roller shaft is mounted on the rotating roller shaft supports.

7. A cell winding method using the thermal composite winding machine according to any one of claims 1 to 6, characterized in that, Includes the following steps: The first electrode unwinding mechanism, the second electrode unwinding mechanism, the first diaphragm unwinding mechanism, and the second diaphragm unwinding mechanism respectively unwind the first electrode, the second electrode, the first diaphragm, and the second diaphragm. The first electrode unwinding mechanism includes a feeding clamp and an electrode cutter arranged in sequence, which feed the first electrode by cutting and feeding it. The second electrode unwinding mechanism includes a cutting, separating, and adhesive-applying mechanism, which cuts the second electrode and then connects the cut strips together with adhesive tape. When the second electrode passes through the cutting, separating, and adhesive-applying mechanism, it is cut and connected with adhesive tape at the cutting, separating, and adhesive-applying mechanism to form a sheet with discontinuous electrode sheets and continuous strips. The first electrode, the second electrode, the first diaphragm, and the second diaphragm are stacked in the order of first electrode, first diaphragm, second electrode, and second diaphragm and intermittently thermally bonded at the intermittent thermal bonding mechanism to obtain a composite electrode. During thermal bonding, the first electrode is located on the outermost side, and the thermal bonding results in a composite electrode with a wavy surface on one side. The length of the first electrode is greater than the length of the second electrode, the first diaphragm, and the second diaphragm. The traction mechanism pulls the composite electrode sheet; The composite electrode is wound into a battery cell at the winding head.

8. The cell winding method as described in claim 7, characterized in that: When the intermittent thermal bonding mechanism performs thermal bonding on the electrode and the diaphragm... The unwound electrode and diaphragm are wound onto the compensating roller, with the first electrode located on the outer side; The hot pressing roller and the compensation roller rotate around their respective axes at a set speed, and the electrode and diaphragm are carried between the hot pressing roller and the compensation roller; The hot press roller is controlled to approach and press against the compensation roller to thermally bond the electrode and the separator. Then, the hot press roller is controlled to move away from the compensation roller, and the electrode and the separator cannot be bonded together. The compensation roller rotates to drive the composite sheet obtained after hot pressing backward. After traveling a certain distance, the hot press roller is controlled to approach and press against the compensation roller again to thermally bond the electrode and the separator again. Then, the hot press roller is controlled to move away from the compensation roller, and the above process is repeated to perform intermittent thermal bonding of the electrode and the separator. Alternatively, the unwound electrode and diaphragm are wound onto the compensating roller, with the first electrode located on the outer side; The hot pressing roller and the compensation roller rotate around their respective axes at a set speed. The hot pressing roller presses on the compensation roller, and the electrode sheet and diaphragm are carried between the hot pressing roller and the compensation roller. The pressure of the hot pressing roller on the compensation roller is controlled so that the pressure of the hot pressing roller on the compensation roller reaches the thermal bonding pressure threshold to thermally bond the electrode and the separator. Then the pressure of the hot pressing roller on the compensation roller is controlled so that the pressure of the hot pressing roller on the compensation roller is less than the thermal bonding pressure threshold, so that the electrode and the separator cannot be bonded together. The rotating compensating roller drives the composite sheet obtained after hot pressing backward. After traveling a certain distance, the pressure of the hot pressing roller on the compensating roller is controlled again to reach the hot composite pressure threshold to perform hot composite of the electrode and the separator. Then, the pressure of the hot pressing roller on the compensating roller is controlled to be less than the hot composite pressure threshold, and the above process is repeated to perform hot composite of the electrode and the separator.

9. The cell winding method as described in claim 7, characterized in that: The traction mechanism includes a first traction roller and a second traction roller arranged opposite to each other. The second traction roller includes a main shaft, a roller frame arranged on the main shaft, a roller shaft arranged on the roller frame, and rollers arranged on the roller shaft. A plurality of guide rollers are arranged on the material belt movement path between the traction mechanism and the winding head. The guide rollers include patterned rollers. The patterned rollers include a main roller shaft and a plurality of rotating roller shafts arranged circumferentially around the main roller shaft. The composite electrode sheet is conveyed between the first traction roller and the second traction roller. The first electrode sheet and the second traction roller are opposite each other. When the second traction roller presses on the first traction roller, the roller is always pressing on the first traction roller and in contact with the first electrode sheet. And / or, when the composite electrode passes around the roller, the side where the first electrode is located comes into contact with the rotating roller shaft.

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