Tension balancing mechanism, battery cell winding machine and battery cell winding method

Abstract

Tension balancing mechanism, battery cell winding machine and battery cell winding method, the tension balancing mechanism is arranged between the diaphragm tension control mechanism and the winding needle of the battery cell winding machine and / or before the positive plate enters the winding needle and / or before the negative plate enters the winding needle, the tension balancing mechanism comprises a tension balancing roller which can rotate around its own axis and a tension balancing roller rotation driving unit which drives the rotation of the tension balancing roller, the material belt such as diaphragm and plate is sent to the winding needle after passing through the tension balancing roller, and the tension balancing roller rotation driving unit outputs a torque to the tension balancing roller which is in the same direction as the running direction of the material belt during winding. The tension balancing mechanism is arranged before the material belt such as diaphragm and plate is sent into the winding needle, the tension balancing roller rotation driving unit outputs a torque to the tension balancing roller which is in the same direction as the running direction of the material belt, the torque can balance the tension of the tension control mechanism, realize the winding state of the material belt tension close to zero or low tension state, reduce the internal stress of the battery cell and reduce the risk of wrinkling of the inner layer of the battery cell.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of lithium battery manufacturing equipment, and particularly relates to a tension balancing mechanism for a separator or a pole piece, a battery cell winding machine and a battery cell winding method. BACKGROUND

[0002] The battery cell of a lithium battery is mainly manufactured by two processes, one is a winding process, and the other is a stacking process. The winding process is to wind the pole piece and the separator by using a winding machine to manufacture the battery cell. Figure 1 As shown in the figure, when the battery cell is wound, the positive pole piece 101, the first separator 102, the negative pole piece 103 and the second separator 104 are sequentially stacked together, and then wound by the winding needle 200 to manufacture the battery cell. Figure 1 As shown in the figure, when the battery cell is wound, the positive pole piece 101, the first separator 102, the negative pole piece 103 and the second separator 104 are sequentially stacked together, and then wound by the winding needle 200 to manufacture the battery cell. Figure 1 The hollow arrow direction is the winding direction of the winding needle 200. The positive pole piece 101 and the negative pole piece 103 are unwound from the positive pole piece roll (not shown) and the negative pole piece roll (not shown) respectively, pass through the pole piece deviation rectifying mechanism, and are wound together by the winding needle 200 together with the first separator 102 and the second separator 104. The first separator 102 and the second separator 104 separate the positive pole piece 101 and the negative pole piece 103. After being unwound from the separator roll 105, the first separator 102 and the second separator 104 pass through the tension control mechanism 106, and then are stacked together with the positive pole piece 101 and the negative pole piece 103.

[0003] With the increasing requirement for the energy density performance of the lithium battery, in order to improve the energy density, the thickness of the pole piece and the separator is thinner and thinner, and the thinner the thickness of the material, the more easily the material is deformed due to stress in the winding process. The thickness of the separator is thinner than that of the pole piece, and the separator is more easily deformed due to stress in the winding process. The separator passes through the tension control mechanism and various over-rollers in the winding process. The tension control mechanism is used to provide a certain tension for the separator, and the over-roller is in contact with the separator, and there is a frictional resistance between the over-roller and the separator. Therefore, for the separator, it is mainly subjected to the following forces in the winding process: the tension F1 output by the tension control mechanism, the winding tension F2 of the separator and the frictional force F3 of the over-roller, wherein the frictional force F3 of the over-roller is usually much smaller than the tension F1 output by the tension control mechanism. When winding at a constant speed, the three forces satisfy the following condition: F2=F1+N’x F3, N’ is the number of over-rollers through which the separator passes after the tension control mechanism. Figure 1 As shown in the figure, after the tension control mechanism, the second separator 104 needs to pass through two over-rollers, therefore, F2=F1+2xF3. As can be seen, the separator cannot be wound at a zero winding tension, so that stress exists in the inner layer of the battery cell, and the stress causes the separator to be deformed, and the deformation of the separator easily causes the inner layer of the battery cell to be wrinkled, thereby affecting the quality of the battery cell. SUMMARY

[0004] The present application aims to provide a tension balancing mechanism capable of reducing the winding tension of a material belt such as a separator or a pole piece, a battery cell winder and a battery cell winding method.

[0005] To achieve the above-mentioned object, the present application adopts the following technical solutions:

[0006] The tension balancing mechanism comprises a tension balancing roller rotatable around its own axis and a tension balancing roller rotation driving unit for driving the rotation of the tension balancing roller, the material belt passes through the tension balancing roller and then reaches the winding needle of the battery cell winder, and the tension balancing roller rotation driving unit outputs a torque in the same direction as the running direction of the material belt during winding.

[0007] Further, the winding tension of the material belt during uniform winding is F2=F1-M / r+NxF3, and the winding tension of the material belt during accelerated winding is F2=F1-M / r+NxF3+NxF4, wherein F1 is the force exerted on the material belt by the material belt tension control mechanism of the battery cell winder, M is the torque output by the tension balancing roller rotation driving unit, N is the number of passing rollers through which the material belt passes after the tension balancing mechanism, r is the radius of the tension balancing roller, F3 is the friction force of the passing rollers, and F4 is the inertial force of the passing rollers.

[0008] Further, the torque output by the tension balancing roller rotation driving unit during uniform winding is M=rxF1, or M / r>F1 during accelerated winding.

[0009] Further, the tension balancing mechanism further comprises a pressing roller that can press on the tension balancing roller.

[0010] Further, the tension balancing mechanism further comprises a tension balancing mechanism fixing frame, a pressing roller driving unit and a pressing roller support, the tension balancing roller is rotatably arranged on the tension balancing mechanism fixing frame around its own axis, the pressing roller is arranged on the pressing roller support, and the pressing roller support can approach or move away from the tension balancing roller under the driving of the pressing roller driving unit, thereby driving the pressing roller to press on or move away from the tension balancing roller.

[0011] The present application further provides a battery cell winder, comprising a separator unwinding mechanism, a separator tension control mechanism, a positive pole piece unwinding mechanism, a negative pole piece unwinding mechanism and a winding needle, and the aforementioned tension balancing mechanism is arranged between the separator tension control mechanism and the winding needle, and / or before the positive pole piece enters the winding needle, and / or before the negative pole piece enters the winding needle.

[0012] Further, the tension balance mechanism is arranged between the diaphragm tension control mechanism and the winding needle, and the diaphragm is sent to the winding needle after passing through the tension balance roller, and the tension balance roller rotation driving unit outputs a torque in the same direction as the diaphragm running direction during winding.

[0013] And / or, the positive plate is unwound by the positive plate unwinding mechanism, and the tension balance mechanism is arranged before entering the winding needle, and the positive plate is sent to the winding needle after passing through the tension balance roller, and the tension balance roller rotation driving unit outputs a torque in the same direction as the positive plate running direction during winding.

[0014] And / or, the negative plate is unwound by the negative plate unwinding mechanism, and the tension balance mechanism is arranged before entering the winding needle, and the negative plate is sent to the winding needle after passing through the tension balance roller, and the tension balance roller rotation driving unit outputs a torque in the same direction as the negative plate running direction during winding.

[0015] The application also provides an electric core winding method, comprising the following steps:

[0016] The positive plate and the negative plate are respectively unwound by the positive plate unwinding mechanism and the negative plate unwinding mechanism of the electric core winding machine, and the diaphragm is unwound by the diaphragm unwinding mechanism of the electric core winding machine.

[0017] The tension balance mechanism is arranged between the diaphragm tension control mechanism and the winding needle of the electric core winding machine, and / or before the positive plate enters the winding needle, and / or before the negative plate enters the winding needle, the tension balance mechanism comprises a tension balance roller which can rotate around its own axis and a tension balance roller rotation driving unit which drives the rotation of the tension balance roller, and the tension balance roller rotation driving unit outputs a torque in the same direction as the material belt running direction during winding.

[0018] The diaphragm and / or the positive plate and / or the negative plate are sent to the winding needle for winding after passing through the tension balance mechanism to form an electric core.

[0019] Further, the torque M output by the tension balance roller rotation driving unit during uniform winding is M=r×F1; or during accelerated winding, M / r>F1.

[0020] Further, the tension balance mechanism is arranged between the diaphragm tension control mechanism and the winding needle, and the diaphragm passes through the tension balance roller, and the tension balance roller rotation driving unit outputs a torque in the same direction as the diaphragm running direction during winding, and the diaphragm is sent to the winding needle after passing through the tension balance mechanism.

[0021] And / or, the positive plate is unwound by the positive plate unwinding mechanism, and a tension balancing mechanism is arranged before entering the winding needle, the positive plate bypasses the tension balancing roller, the tension balancing roller rotation driving unit outputs a torque in the same direction as the positive plate walking direction when unwinding and winding to the tension balancing roller, and the positive plate is sent to the winding needle after passing through the tension balancing mechanism.

[0022] And / or, the negative plate is unwound by the negative plate unwinding mechanism, and a tension balancing mechanism is arranged before entering the winding needle, the negative plate bypasses the tension balancing roller, the tension balancing roller rotation driving unit outputs a torque in the same direction as the negative plate walking direction when unwinding and winding to the tension balancing roller, and the negative plate is sent to the winding needle after passing through the tension balancing mechanism.

[0023] From the above technical solutions, it can be known that the tension balancing mechanism is arranged before the separator and the plate are sent into the winding needle, the tension balancing mechanism is located after the separator / plate tension control mechanism, the tension balancing roller rotation driving unit outputs a torque in the same direction as the walking direction of the material belt to the tension balancing roller, when the torque acts on the material belt, the tension of the material belt after unwinding can be balanced, the friction resistance of the roller, and the like, so that the tension of the material belt after passing through the tension balancing roller is reduced, the material belt is wound in a state close to zero or low tension, thereby the internal stress of the battery cell can be reduced, the risk of wrinkling of the inner layer of the battery cell is reduced, and the quality of the battery cell is ensured. BRIEF DESCRIPTION OF DRAWINGS

[0024] In order to more clearly illustrate the embodiments of the present application, the drawings needed in the embodiments or the prior art description will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0025] Figure 1 It is a winding schematic diagram of a battery cell winding machine;

[0026] Figure 2 It is a winding schematic diagram of a battery cell winding machine of the embodiment of the present application;

[0027] Figure 3 It is a structure schematic diagram of a separator tension balancing mechanism of the embodiment of the present application;

[0028] Figure 4 It is a sectional view of the separator tension balancing mechanism of the embodiment of the present application.

[0029] The specific embodiments of the present application will be further described in detail below with reference to the accompanying drawings. DETAILED DESCRIPTION

[0030] 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.

[0031] like Figure 2 As shown, the battery cell winding machine of this embodiment includes a first diaphragm unwinding mechanism 1, a second diaphragm unwinding mechanism 2, a diaphragm tension control mechanism 3, a winding needle 4, and a tension balancing mechanism 5. The first diaphragm unwinding mechanism 1 and the second diaphragm unwinding mechanism 2 are used to unwind the diaphragm roll. After the diaphragm is unwound from the diaphragm roll, it passes through the diaphragm tension control mechanism 3 and the tension balancing mechanism 5 in sequence, and is then sent to the winding needle 4. The winding needle 4 winds the positive electrode sheet 11, the first diaphragm 12, the negative electrode sheet 13, and the second diaphragm 14 to form a core. A diaphragm correction mechanism 6 is provided between the diaphragm tension control mechanism 3 and the tension balancing mechanism 5.

[0032] The tension balancing mechanism 5 comprises a tension balancing roller 5-1, and the diaphragm is wound around the tension balancing roller 5-1. The tension balancing roller 5-1 is outputted with a torque M, and the direction of the torque M is the same as the running direction of the diaphragm during winding, and the winding tension F2 of the diaphragm is reduced through the torque M. The winding tension of the diaphragm (the material belt) of the present application refers to the force acting on the diaphragm when the winding needle drives the diaphragm (the material belt) to wind. In the winding direction, the diaphragm tension control mechanism 3, the tension balancing mechanism 5, and the winding needle 4 are sequentially arranged. After passing through the tension balancing mechanism 5, the diaphragm also passes through a plurality of over rollers 7 before being sent to the winding needle 4 for winding. Taking the second diaphragm 14 as an example, after the tension balancing mechanism 5, the second diaphragm 14 also passes through 3 over rollers 7 before being sent to the winding needle 4 for winding. Since the tension balancing mechanism 5 is located after the diaphragm tension control mechanism 3, and the direction of the torque M outputted at the tension balancing mechanism 5 is the same as the running direction of the diaphragm during winding, when winding at a constant speed, the winding tension F2 of the second diaphragm = F1-M / r+3xF3, wherein r is the radius of the tension balancing roller 5-1, F1 is the force acting on the diaphragm by the diaphragm tension control mechanism, and M is the torque outputted at the tension balancing roller. It can be known from the above formula that the winding tension of the second diaphragm can be reduced due to the existence of the tension balancing mechanism. By controlling the torque M outputted to the tension balancing roller, when M / r=F1, F2=NxF3 (N is the number of over rollers through which the diaphragm passes after the tension balancing mechanism), since the friction force F3 of the over roller is very small and can be ignored, the winding at near-zero diaphragm tension or low diaphragm tension can be realized, so as to reduce the stress of the inner layer of the battery cell and reduce the risk of wrinkling of the inner layer of the battery cell. The above is the analysis of the constant-speed winding, and when accelerating the winding, the diaphragm is subjected to the action of F1, F2, F3, and the inertia force F4 (the force required for acceleration) of the over roller, and at this time, F2=F1-M / r+NxF3+NxF4. In order to realize the winding at zero diaphragm tension or low diaphragm tension when accelerating the winding, M / r should be larger, M / r>F1, such as M / r=F1+NxF4, so as to balance the inertia force of the over roller and realize the winding at near-zero diaphragm tension or low diaphragm tension.

[0033] Figure 3 and Figure 4 The structure diagram of the tension balancing mechanism of the present embodiment is as shown in Figure 3 and Figure 4As shown, the tension balancing mechanism 5 of the embodiment includes a tension balancing roller 5-1, a pressure roller 5-2, a tension balancing roller rotation driving unit 5-3, a tension balancing mechanism fixing frame 5-4, a pressure roller driving unit 5-5, and a pressure roller support 5-6. The tension balancing roller 5-1 is rotatably arranged on the tension balancing mechanism fixing frame 5-4, and is installed on the tension balancing mechanism fixing frame 5-4 through a bearing 5-8. The tension balancing roller 5-1 is driven to rotate around its own axis by the tension balancing roller rotation driving unit 5-3, and the tension balancing roller rotation driving unit 5-3 outputs a torque in the same direction as the direction in which the diaphragm is wound to the tension balancing roller 5-1. The tension balancing roller rotation driving unit 5-3 of the embodiment is a motor, the output shaft of the motor is connected to the tension balancing roller 5-1 through a shaft coupling 5-7, so as to drive the tension balancing roller 5-1 to rotate. The pressure roller 5-2 is arranged on the pressure roller support 5-6 through a bearing 5-8. The pressure roller support 5-6 drives the pressure roller 5-2 to move close to or away from the tension balancing roller 5-1 under the drive of the pressure roller driving unit 5-5. When the pressure roller 5-2 is close to and pressed on the tension balancing roller 5-1, the torque M acting on the diaphragm can be accurately controlled to make M / r=F1 or M / r>F1. The pressure roller driving unit 5-5 of the embodiment is a pneumatic cylinder, which is fixed on the tension balancing mechanism fixing frame 5-4, and the piston rod of the pneumatic cylinder is connected to the pressure roller support 5-6. Thus, when the pneumatic cylinder operates, the pressure roller 5-2 is moved by the pressure roller support 5-6.

[0034] In optional embodiments, the pressure roller can also not be arranged. Without the pressure roller, it is difficult to accurately control the tension of the tension balancing mechanism only by the tension balancing roller using the friction force between the tension balancing roller and the diaphragm, and it is difficult to achieve M / r=F1. Although the winding tension of the diaphragm can be reduced to a certain extent, it is difficult to achieve zero-tension winding of the diaphragm.

[0035] The tension balancing mechanism of the application can be applied to the diaphragm to balance the tension of the diaphragm, and can also be applied to the positive electrode sheet and / or the negative electrode sheet to make the electrode sheet pass through the tension balancing roller in the tension balancing mechanism to balance the tension of the electrode sheet and achieve low-tension winding of the electrode sheet.

[0036] The tension balancing mechanism of the application can be applied to the diaphragm to balance the tension of the diaphragm, and can also be applied to the positive electrode sheet and / or the negative electrode sheet to make the electrode sheet pass through the tension balancing roller in the tension balancing mechanism to balance the tension of the electrode sheet and achieve low-tension winding of the electrode sheet. Figure 2 The method for winding the battery cell of the embodiment will be described below. As shown in Figure 2 The method for winding the battery cell of the application is as follows:

[0037] The positive electrode sheet 11 and the negative electrode sheet 13 are unwound by the positive electrode sheet unwinding mechanism (not shown) and the negative electrode sheet unwinding mechanism (not shown) respectively, and the diaphragm (the first diaphragm 12 and the second diaphragm 14) is unwound by the diaphragm unwinding mechanism (the first diaphragm unwinding mechanism 1 and the second diaphragm unwinding mechanism 2);

[0038] The tension balancing mechanism 5 is arranged between the tension control mechanism 3 and the winding needle 4, and includes a tension balancing roller 5-1 and a tension balancing roller rotation driving unit 5-3 for driving the tension balancing roller 5-1 to rotate, wherein the tension balancing roller 5-1 is rotatable about its own axis, and the tension balancing roller rotation driving unit 5-3 outputs a torque to the tension balancing roller 5-1 in the same direction as the direction of the separator film during winding;

[0039] The separator film is sent to the winding needle 4 after passing through the tension control mechanism 3 and the tension balancing mechanism 5, and is wound together with the positive plate 11 and the negative plate 13 to form the battery cell.

[0040] In the optional embodiment, the tension balancing mechanism 5 further includes a pressing roller 5-2 which is capable of being pressed against the tension balancing roller 5-1, and the torque M output by the tension balancing roller rotation driving unit 5-3 is M = r x F1, wherein r is the radius of the tension balancing roller, and F1 is the force applied to the separator film by the tension control mechanism. By arranging the tension balancing mechanism and controlling the size of the torque of the tension balancing mechanism, zero-tension winding or low-tension winding of the separator film is achieved, and the stress in the inner layer of the battery cell is reduced. When the winding speed is uniform, the winding tension F2 of the separator film is F2 = F1 - M / r + N x F3, and when the winding speed is accelerated, the winding tension F2 of the separator film is F2 = F1 - M / r + N x F3 + N x F4, wherein N is the number of rollers through which the separator film passes after the tension balancing mechanism.

[0041] By arranging the tension balancing mechanism before the separator film is sent to the winding needle, the tension balancing roller rotation driving unit outputs a torque in the same direction as the direction of the separator film, which reduces the tension of the separator film after passing through the tension balancing roller, and the tension is equal to zero or close to zero, so that the zero-tension or low-tension winding of the separator film during the winding process is ensured, the internal stress of the battery cell is reduced, and the deformation of the separator film is avoided.

[0042] Similarly, the tension balancing mechanism can also be arranged before the positive plate and the negative plate enter the winding needle. After the positive / negative plate is unwound by the positive plate unwinding mechanism, the tension balancing mechanism is arranged before the positive / negative plate enters the winding needle, so that the positive / negative plate passes through the tension balancing roller in the tension balancing mechanism, and the tension balancing roller rotation driving unit outputs a torque in the same direction as the direction of the positive / negative plate during winding. The positive / negative plate is sent to the winding needle after passing through the tension balancing mechanism. The tension balancing mechanism balances the tension of the plate, and the low-tension winding of the plate is achieved.

[0043] The foregoing description of the disclosed embodiments enables a person skilled in the art to make or use the application. Modifications of these embodiments will occur to persons of skill in the art, and that the appended claims are intended to cover all such modifications that do not depart from the true spirit and scope of the application. Therefore, the application is not limited to the embodiments shown but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A battery cell winding machine, characterized in that, include: The system includes a diaphragm unwinding mechanism, a diaphragm tension control mechanism, a winding needle, and a tension balancing mechanism. The tension balancing mechanism is located after the diaphragm tension control mechanism and includes: a tension balancing roller rotatable about its own axial direction, a tension balancing roller rotation drive unit that drives the tension balancing roller to rotate, and a pressure roller that presses against the tension balancing roller. The diaphragm, after passing over the tension balancing roller, is fed to the winding needle of the cell winding machine. The tension balancing roller rotation drive unit outputs a torque M to the tension balancing roller in the same direction as the diaphragm's feed direction during winding. When the pressure roller presses against the tension balancing roller, it controls the torque M to act on the diaphragm so that M / r = F1 or M / r > F1, where r is... The radius of the tension balancing roller, F1 is the force exerted on the diaphragm by the diaphragm tension control mechanism, the winding tension of the diaphragm during uniform winding is F2 = F1 - M / r + N × F3, the winding tension of the diaphragm during accelerated winding is F2 = F1 - M / r + N × F3 + N × F4, where N is the number of rollers the diaphragm passes through after the tension balancing mechanism, F3 is the frictional force of the rollers, and F4 is the inertial force of the rollers. In the winding direction, the diaphragm tension control mechanism, the tension balancing mechanism, and the winding needle are arranged in sequence. After passing through the tension balancing mechanism, the diaphragm passes around the rollers and is sent to the winding needle for winding. The winding tension of the diaphragm is the force exerted on the diaphragm when the winding needle drives the diaphragm to wind.

2. The cell winding machine as described in claim 1, characterized in that: The tension balancing mechanism further includes a tension balancing mechanism fixing frame, a pressure roller driving unit, and a pressure roller support; the tension balancing roller is rotatably mounted on the tension balancing mechanism fixing frame around its own axis, the pressure roller is mounted on the pressure roller support, and the pressure roller support can move closer to or further away from the tension balancing roller under the drive of the pressure roller driving unit, thereby driving the pressure roller to press on or away from the tension balancing roller.

3. The cell winding machine as described in claim 1, characterized in that: It also includes a positive electrode unwinding mechanism and a negative electrode unwinding mechanism; the tension balancing mechanism is provided before the positive electrode enters the winding needle, and / or before the negative electrode enters the winding needle.

4. The cell winding machine as described in claim 3, characterized in that: After the positive electrode sheet is unwound by the positive electrode sheet unwinding mechanism, the tension balancing mechanism is set before it enters the winding needle. After the positive electrode sheet passes around the tension balancing roller, it is sent to the winding needle. The tension balancing roller rotation drive unit outputs torque to the tension balancing roller in the same direction as the positive electrode sheet's belt travel direction during winding. And / or, after the negative electrode sheet is unwound by the negative electrode sheet unwinding mechanism, a tension balancing mechanism is provided before it enters the winding needle. After the negative electrode sheet passes around the tension balancing roller, it is sent to the winding needle. The tension balancing roller rotation drive unit outputs a torque to the tension balancing roller in the same direction as the negative electrode sheet's belt travel direction during winding.

5. A method for winding a battery cell, characterized in that, Winding using the cell winding machine as described in any one of claims 1 to 4 includes the following steps: The positive electrode sheet and the negative electrode sheet are unwound by the positive electrode sheet unwinding mechanism and the negative electrode sheet unwinding mechanism of the cell winding machine, respectively, and the diaphragm is unwound by the diaphragm unwinding mechanism of the cell winding machine. A tension balancing mechanism is provided between the diaphragm tension control mechanism and the winding needle of the battery cell winding machine, and before the positive electrode sheet enters the winding needle, and / or before the negative electrode sheet enters the winding needle. The tension balancing mechanism includes a tension balancing roller that can rotate about its own axis, a tension balancing roller rotation drive unit that drives the tension balancing roller to rotate, and a pressure roller that can press on the tension balancing roller. The tension balancing roller rotation drive unit outputs a torque to the tension balancing roller that is in the same direction as the material carrying the belt during winding. After the diaphragm and / or positive electrode and / or negative electrode pass through the tension balancing mechanism, they are sent to the winding needle for winding to form a battery cell. For the tension balancing mechanism located between the diaphragm tension control mechanism and the winding needle, the diaphragm passes around the tension balancing roller. When the pressure roller presses on the tension balancing roller, the tension balancing roller rotation drive unit outputs a torque M in the same direction as the diaphragm's belt travel direction during winding to the tension balancing roller, so that M / r = F1 or M / r > F1, where r is the radius of the tension balancing roller and F1 is the force exerted on the diaphragm by the diaphragm tension control mechanism.

6. The cell winding method as described in claim 5, characterized in that: After the positive electrode sheet is unwound by the positive electrode sheet unwinding mechanism, a tension balancing mechanism is set before it enters the winding needle. The positive electrode sheet passes around the tension balancing roller. The tension balancing roller rotation drive unit outputs a torque to the tension balancing roller in the same direction as the positive electrode sheet's belt travel direction during winding, so that the positive electrode sheet is sent to the winding needle after passing through the tension balancing mechanism. And / or, after the negative electrode sheet is unwound by the negative electrode sheet unwinding mechanism, a tension balancing mechanism is set before it enters the winding needle. The negative electrode sheet passes around the tension balancing roller. The tension balancing roller rotation drive unit outputs a torque to the tension balancing roller in the same direction as the negative electrode sheet's belt travel direction during winding, so that the negative electrode sheet is sent to the winding needle after passing through the tension balancing mechanism.

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