Electrode sheet folding control method and device, electrode sheet folding device, and battery production system

Abstract

The present application relates to an electrode sheet folding control method and device, an electrode sheet folding device, and a battery production system. The electrode sheet folding control method comprises: during a folding process of an electrode sheet group, controlling a conveying component to operate, so as to drive the electrode sheet group to move towards a folding table; and when a lamination region which is being folded starts to appear or is already present on the folding table, controlling at least one of the conveying component and the folding table to rotate around respective axes, such that the connection line distance between a conveying end of the conveying component and a folding start point of the lamination region on the folding table that are located on the same side is increased. In this way, an avoidance space can be provided for the folding of the lamination region, thus facilitating stress release of the lamination region during folding, reducing the pulling force of a lamination region in a folded state on a lamination region in a non-folded state, and reducing the bending and warping degree of the lamination region at a folding position. In this case, a formed laminated structure has a reduced probability of abnormal gaps at the folding position, thus effectively reducing the probability of lithium precipitation of an electrode sheet at the folding position, and improving the quality of a laminated battery.

Description

Pole piece folding control method, device, pole piece folding device and battery production system

[0001] Related applications

[0002] This application claims priority to Chinese patent application number 2023111683275, filed on September 12, 2023, entitled “Pole folding control method, device, pole piece folding device and battery production system,” the entire text of which is hereby incorporated by reference. Technical Field

[0003] The present application relates to the field of battery production technology, and in particular to a pole piece folding control method and device, a pole piece folding device, and a battery production system. Background Art

[0004] The electrode assembly is the component in a battery where the electrochemical reaction occurs. It is primarily composed of a wound or stacked positive and negative electrode sheets, typically with a separator between them. During the stacking process, the stacked negative, separator, and positive electrode sheets are folded. However, due to limitations in traditional electrode folding methods, lithium deposition can easily occur at the folded area, affecting the quality of the stacked battery.

[0005] Summary of the Invention

[0006] Based on this, it is necessary to provide a pole piece folding control method, device, pole piece folding device and battery production system to reduce the probability of lithium deposition at the folding part of the pole piece and improve the quality of the stacked battery.

[0007] In the first aspect, the present application provides a pole piece folding control method, wherein the pole piece folding mechanism includes a stacking platform and a conveying component for conveying a pole piece group, wherein the pole piece group has a plurality of stacking areas along its own length direction, and the stacking areas have a folding starting point on the stacking platform, and the conveying component includes a first roller and a second roller located on both sides of the pole piece group, and the ends of the first roller and the second roller respectively in contact with the pole piece group are both conveying ends, and the axis of the conveying component is located on the line connecting the two conveying ends; the pole piece folding control method includes the following steps: controlling the conveying component to drive the pole piece group toward the stacking platform; in response to the stacking area folding on the stacking platform, controlling the conveying component and / or the stacking platform to rotate around their respective axes to increase the distance between the conveying end located on the same side of the line connecting the axes of the conveying component and the stacking platform and the folding starting point.

[0008] The above-mentioned electrode folding control method controls the operation of the conveying component to drive the electrode group toward the stacking platform during the folding process of the electrode group. When a laminated area on the stacking platform begins to fold or has already folded, the conveying component and at least one of the stacking platform are controlled to rotate around their respective axes, so that the distance between the conveying end of the conveying component on the same side and the folding starting point of the laminated area on the stacking platform increases. This can provide space for the folding of the laminated area, facilitate its stress release during folding, reduce the pulling force of the laminated area in the folding state on the laminated area that has not yet folded, and reduce the degree of bending and warping of the laminated area at the folding. At this time, the probability of the laminate structure forming a gap abnormality at the folding is reduced, thereby effectively reducing the probability of lithium deposition at the folding of the electrode, and improving the quality of the laminated battery.

[0009] In some embodiments, the step of controlling the conveying component and / or the stacking platform to rotate about their respective axes includes: controlling the conveying component and / or the stacking platform to rotate about their respective axes continuously and periodically to execute a rotation strategy, wherein the rotation strategy includes a first step and a second step; wherein the first step includes rotating away from an initial position of the conveying component or the stacking platform in a first direction; and rotating to the initial position in a second direction; and the second step includes rotating away from the initial position in the second direction; and rotating to the initial position in the first direction, wherein the first direction is opposite to the second direction. In this way, during the folding process of the electrode assembly, controlling at least one of the conveying component and the stacking platform to periodically execute the rotation strategy provides effective clearance space for the folding process of the laminated area, facilitates the release of force on the laminated area, reduces the degree of bending and warping in the laminated area, and improves the quality of the laminated battery.

[0010] In some embodiments, the step of executing the rotation strategy includes: controlling the stacking platform to execute the second step when the laminated area is folded along the first direction; and controlling the stacking platform to execute the first step when the laminated area is folded along the second direction. Thus, by setting the stacking platform's initial rotation direction opposite to the folding and bending direction of the laminated area, the distance between the conveying end of the conveying component and the starting point of the folding of the laminated area can be increased, thereby increasing the space between the conveying component and the stacking platform, facilitating stress release, reducing bending and warping at the folding area, and improving the quality of the laminated battery.

[0011] In some embodiments, the step of executing the rotation strategy includes: controlling the conveying component to execute the first step when the laminated area is folded along a first direction; and controlling the conveying component to execute the second step when the laminated area is folded along a second direction. Thus, by aligning the conveying component's initial rotation direction with the laminated area's folding and bending direction, the distance between the conveying end of the conveying component and the laminated area's folding starting point can be increased, thereby increasing the space between the conveying component and the stacking platform, facilitating stress release, reducing warping at the folding point, and improving the quality of the laminated battery.

[0012] In some embodiments, the positions that the conveyor member or stacking platform passes through in any direction of rotation include an initial position and an extreme position, and the extreme position is set at an acute angle to the initial position. In this way, setting the rotation path of the conveyor member or stacking platform between the initial position and the extreme position facilitates the association of the reciprocating rotation of the conveyor member or stacking platform with the folding action of the lamination area, thereby improving the effective control of the folding process of the electrode stack.

[0013] In some embodiments, the angle between the extreme position and the initial position is denoted as θ, where, when one of the conveyor component or the stacking platform is controlled to execute a rotation strategy, 0°<θ≤60°. Thus, controlling the angle θ between 0° and 60° facilitates stress relief during the folding process of the electrode assembly, improving the quality of the laminated battery and also enhancing the stability of the electrode assembly on the stacking platform.

[0014] In some embodiments, θ further satisfies the condition: 15°≤θ≤30°. Thus, the rotation angle from the initial position to the extreme position is further controlled within a range of 15° to 30°, thereby facilitating more precise control over the folding process of the electrode assembly and effectively improving the folding effect of the electrode assembly.

[0015] In some embodiments, when the conveying component and / or stacking platform rotates from the initial position to the extreme position, the conveying displacement of the electrode sheet assembly by the conveying end of the conveying component is controlled to be a first displacement, and the ratio of the first displacement to the length of the stacking area is recorded as γ, where 0.3≤γ≤0.7. In this way, the ratio of the first displacement to the length of the stacking area is controlled to be between 0.3 and 0.7, so that the electrode sheet assembly is conveyed by at least 0.3 of the stacking area when the conveying component or stacking platform rotates from the initial position to the extreme position, which is beneficial to reducing the bending and warping of the electrode sheet assembly at the folding point and improving the quality of the laminated battery.

[0016] In some embodiments, γ further satisfies the condition: 0.3≤γ≤0.4. Thus, further controlling the ratio of the first displacement to the length of the laminated region to 0.3-0.4 facilitates further effective control of the electrode assembly folding process, thereby improving the controllability of the laminated battery quality.

[0017] In some embodiments, the step of executing the rotation strategy includes: when the conveyor member or stacking platform rotates from an initial position to an extreme position, controlling the conveyor member or stacking platform to rotate first at a first angular velocity and then at a second angular velocity, wherein the first angular velocity is greater than the second angular velocity. Thus, controlling the first angular velocity to be greater than the second angular velocity allows the conveyor member or stacking platform to translate faster at the beginning of folding, which facilitates quickly increasing the distance between the conveyor member and the stacking platform, allowing for rapid stress relief during the folding process, and further improving the quality of the laminated battery.

[0018] In some embodiments, the ratio of the first angular velocity to the second angular velocity is denoted as β, where 1.5≤β≤2.5. Thus, controlling the ratio of the first angular velocity to the second angular velocity within a range of 1.5 to 2.5 can improve the angular velocity response to stress release during the folding process, thereby enhancing the folding effect. At the same time, it can also effectively control the rotation of the conveyor component or stacking platform, ensuring stable rotation of the conveyor component or stacking platform when executing the rotation strategy.

[0019] In some embodiments, β further satisfies the condition: 1.8≤β≤2.2. Thus, the ratio of the first angular velocity to the second angular velocity is further controlled within a range of 1.8 to 2.2, thereby achieving a better angular velocity response to stress release during the folding process and enabling more stable control of the rotation of the conveying member or stacking platform.

[0020] In some embodiments, after the conveyor and / or stacking platform completes the rotation strategy, the conveyor end of the conveyor moves the electrode stack by at least the length of two stacking zones. Thus, linking the rotation strategy cycle with the conveyor cycle allows for more controllable folding quality and improved product consistency.

[0021] In some embodiments, the step of executing the rotation strategy includes: controlling the conveying component and / or the stacking platform to move away from each other by a predetermined displacement amount each time the first or second step is completed. This effectively compensates for the space compressed by the increased number of folds, facilitating the folding of the electrode assembly; it also facilitates stress relief during the folding process, thereby improving the quality of the laminated battery.

[0022] In some embodiments, the ratio of the preset displacement to the thickness of the electrode group in the lamination area is denoted as α, where 1≤α≤5. Thus, controlling the ratio of the preset displacement to the thickness of the electrode group in the lamination area to be between 1 and 5 facilitates appropriate displacement of the conveying member or the stacking platform after folding, leaving a reasonable space between the conveying member and the stacking platform for the electrode group, thereby achieving a stable and efficient folding process.

[0023] In some embodiments, α further satisfies the condition: 2≤α≤3. Thus, the value of α is further controlled between 2 and 3, so that after each folding, the space between the conveying component and the stacking table is more reasonably controlled, thereby making the folding process of the electrode assembly on the stacking table more stable.

[0024] In some embodiments, before controlling the conveying member and / or the stacking platform to rotate about their respective axes, the method further includes controlling the minimum spacing between the conveying end of the conveying member and the working surface of the stacking platform to be an initial spacing, where the ratio of the initial spacing to the length of the stacking area is denoted as λ, with 1.2≤λ≤2. Thus, controlling the ratio of the initial spacing to the length of the stacking area to be between 1.2 and 2 allows for a suspended stacking area between the conveying member and the stacking platform, thereby stabilizing the folding process and improving folding efficiency.

[0025] In some embodiments, λ further satisfies the condition: 1.3≤λ≤1.6. Thus, the ratio of the initial spacing to the length of the lamination area is further controlled between 1.3 and 1.6, facilitating more precise control of the folding of the electrode assembly and further improving the stability and efficiency of the folding process.

[0026] In some embodiments, in response to the step of folding the laminated area on the stacking platform, the method includes controlling the conveying displacement of the conveying end of the conveying component relative to the electrode group to be a second displacement, wherein the ratio of the second displacement to the length of the laminated area is denoted as ε, and 2≤ε≤10. In this way, the conveying displacement of the conveying end of the conveying component relative to the electrode group is controlled to be between 2 and 10, so that at least one laminated area has been folded on the stacking platform, which facilitates stress relief for the laminated area being folded, reduces bending and warping at the folded area, and improves the quality of the laminated battery.

[0027] In some embodiments, ε also satisfies the condition: 2.1≤ε≤2.9. Thus, the conveying displacement of the conveying end of the conveying component to the electrode assembly is further controlled between 2.1 and 2.9, thereby reducing the number of folds in the lamination area on the stacking table before the rotation strategy is executed. This allows the rotation strategy to improve most of the folding process on the electrode assembly, further improving the quality of the laminated battery.

[0028] In the second aspect, the present application provides a pole piece folding control device, which adopts any of the above pole piece folding control methods. The pole piece folding control device includes: a response module, which is used to obtain the folding situation of the stacking area on the stacking table and feedback a signal; an execution module, which is used to control the operation of the conveying component and can control the conveying component and / or the stacking table to rotate around their respective axes according to the signal feedback from the response module.

[0029] In a third aspect, the present application provides a pole piece folding device, which includes: a pole piece folding mechanism, including a stacking table and a conveying component for conveying the pole piece group and folding the pole piece group back and forth on the stacking table; a driving mechanism for driving the conveying component and / or the stacking table to rotate around their respective axes.

[0030] In a fourth aspect, the present application provides a battery production system, which includes the above-mentioned electrode folding device. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments of the present application. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on the drawings without creative work.

[0032] FIG1 is a flow chart of a pole piece folding control method according to some embodiments of the present application.

[0033] FIG2 is a schematic structural diagram of the electrode assembly during the folding process described in some embodiments of the present application.

[0034] FIG3 is a schematic diagram of a structure in which a pole piece assembly described in some embodiments of the present application is bent at a fold.

[0035] FIG4 is a schematic diagram of the gap structure at the folding portion of the laminate structure described in some embodiments of the present application.

[0036] FIG5 is a second flow chart of the pole piece folding control method described in some embodiments of the present application.

[0037] Figure 6 is a structural schematic diagram of the folding process of the pole piece group described in some embodiments of the present application, and (a) to (e) in Figure 6 are structural schematic diagrams corresponding to different steps when the pole piece group described in some embodiments of the present application performs a rotation strategy during the folding process.

[0038] FIG7 is a third flow chart of the pole piece folding control method described in some embodiments of the present application.

[0039] FIG8 is a fourth flow chart of the pole piece folding control method described in some embodiments of the present application.

[0040] Figure 9 is a structural schematic diagram of the folding process of the electrode group described in other embodiments of the present application, and (a) to (e) in Figure 9 are structural schematic diagrams corresponding to different steps when the conveying components of the electrode group described in other embodiments of the present application execute the rotation strategy during the folding process.

[0041] FIG. 10 is a graph showing specific rotation angle amplitudes of the stack described in some embodiments of the present application.

[0042] FIG11 is a schematic structural diagram of a pole piece group in a pole piece folding mechanism before executing a rotation strategy as described in some embodiments of the present application.

[0043] FIG12 is a schematic structural diagram of a pole piece folding control device according to some embodiments of the present application.

[0044] 100. Pole piece folding device; 10. Pole piece folding mechanism; 1a. First displacement; 1b. First axis; 1c. Initial position; 1d. Preset displacement; 1e. Initial spacing; 1f. Gap; 1g. Extreme position; 1h. Second axis; 11. Conveying component; 111. First roller; 112. Second roller; 113. Conveying end; 12. Stacking table; 121. Working surface; 20. Pole piece group; 21. Stacking area; 22. First pole piece; 23. Second pole piece; 24. Diaphragm; 25. Folding point; 26. Folding starting point; 30. Driving mechanism; X, Conveying direction; 200. Response module; 300. Execution module. DETAILED DESCRIPTION

[0045] To make the above-mentioned objects, features, and advantages of the present application more clearly understood, the specific embodiments of the present application are described in detail below with reference to the accompanying drawings. The following description sets forth many specific details to facilitate a full understanding of the present application. However, the present application can be implemented in many other ways than those described herein, and those skilled in the art can make similar improvements without violating the scope of the present application. Therefore, the present application is not limited to the specific embodiments disclosed below.

[0046] In the description of this application, it should be understood that if the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. appear, the orientation or position relationship indicated by these terms is based on the orientation or position relationship shown in the accompanying drawings, which is only for the convenience of describing this application and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on this application.

[0047] In addition, if the terms "first" or "second" appear, these terms are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of technical features indicated. Therefore, a feature specified as "first" or "second" may explicitly or implicitly include at least one of such features. In the description of this application, if the term "plurality" appears, "plurality" means at least two, for example, two, three, etc., unless otherwise specifically defined.

[0048] In this application, unless otherwise specified or limited, the terms "mounted," "connected," "connected," "fixed," etc., should be interpreted broadly. For example, these terms may refer to fixed connections, removable connections, or integration; mechanical connections or electrical connections; direct connections or indirect connections through an intermediary; and internal communication between two components or interaction between two components, unless otherwise specified. Those skilled in the art will understand the specific meanings of these terms in this application based on the specific circumstances.

[0049] In this application, unless otherwise expressly specified or limited, if a first feature is described as being "above" or "below" a second feature, or similar descriptions, this may mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediate medium. Furthermore, when a first feature is described as being "above," "above," or "above" a second feature, it may mean that the first feature is directly above or diagonally above the second feature, or simply means that the first feature is at a higher level than the second feature. When a first feature is described as being "below," "below," or "below" a second feature, it may mean that the first feature is directly below or diagonally below the second feature, or simply means that the first feature is at a lower level than the second feature.

[0050] It should be noted that if an element is referred to as being "fixed to" or "disposed on" another element, it may be directly on the other element or there may be an intermediate element. If an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be an intermediate element. If any, the terms "vertical", "horizontal", "upper", "lower", "left", "right" and similar expressions used in this application are for illustrative purposes only and do not represent the only embodiment.

[0051] Currently, market developments indicate that power batteries are becoming increasingly widely used. They are not only used in energy storage systems such as hydropower, thermal, wind, and solar power plants, but are also widely used in electric vehicles like electric bicycles, electric motorcycles, and electric vehicles, as well as in military equipment and aerospace. As power battery applications continue to expand, market demand is also growing.

[0052] In a battery, the electrode assembly, which is the component where the electrochemical reaction occurs, is typically formed by stacking a positive electrode, a separator, and a negative electrode. During the stacking process, the electrode assembly formed by the stacked negative electrode, separator, and positive electrode can be folded in a Z-shaped structure. For example, one stacking area on the electrode assembly is folded in a right-bending direction on a stacking table. After folding, the connected stacking area is folded in a left-bending direction. This cycle continues to form a Z-shaped stacking structure. Stacked batteries formed using traditional folding methods generally experience lithium deposition at the folding point of the electrode, resulting in reduced quality of the stacked battery.

[0053] Based on this, in order to effectively improve the problem of lithium deposition at the folding part of the laminated structure formed by the traditional folding method, the present application provides a method for controlling the folding of the electrode group. During the folding process of the electrode group, the conveying component is controlled to work and drive the electrode group toward the stacking platform. When a laminated area on the stacking platform begins to fold or has already been folded, at least one of the conveying component and the stacking platform is controlled to rotate around their respective axes, so that the distance between the conveying end of the conveying component on the same side and the folding starting point of the laminated area on the stacking platform increases. This can provide space for the folding of the laminated area, facilitate its stress release during folding, reduce the pulling force of the laminated area in the folding state on the laminated area that has not yet folded, and reduce the degree of bending and warping of the laminated area at the folding part. At this time, the probability of the laminated structure generating gap abnormalities at the folding part is reduced, thereby effectively reducing the probability of lithium deposition at the folding part of the electrode and improving the quality of the laminated battery.

[0054] In some embodiments of the present application, the electrode assembly is a component in the battery where an electrochemical reaction occurs, which can be formed by stacking a positive electrode sheet and a negative electrode sheet, and a separator is usually provided between the positive electrode sheet and the negative electrode sheet. The parts of the positive electrode sheet and the negative electrode sheet with active materials constitute the main body of the electrode assembly, and the parts of the positive electrode sheet and the negative electrode sheet without active materials each constitute a tab. The positive electrode tab and the negative electrode tab can be located together at one end of the main body or respectively at both ends of the main body. During the charge and discharge process of the battery, the positive electrode active material and the negative electrode active material react with the electrolyte, and the tabs connect the electrode terminals to form a current loop.

[0055] According to some embodiments of the present application, please refer to Figures 1 and 2. The present application provides a method for controlling electrode folding. The electrode folding mechanism 10 includes a stacking platform 12 and a conveying component 11 for conveying an electrode group 20, wherein the electrode group 20 has a plurality of stacking areas 21 along its own length direction, and the stacking area 21 has a folding starting point 26 on the stacking platform 12. The conveying component 11 includes a first roller 111 and a second roller 112 located on both sides of the electrode group 20. The ends of the first roller 111 and the second roller 112 that contact the electrode group 20 are both conveying ends 113, and the axis of the conveying component 11 is located on the line connecting the two conveying ends 113. The electrode folding control method includes the following steps:

[0056] S100, controlling the conveying component 11 to drive the electrode group 20 to be conveyed toward the stacking table 12;

[0057] S200, in response to the lamination area 21 being folded on the stacking platform 12, the conveying component 11 and / or the stacking platform 12 are controlled to rotate around their respective axes so that the distance between the conveying end 113 located on the same side of the axis connecting the conveying component 11 and the stacking platform 12 and the folding starting point 26 is increased.

[0058] The electrode folding mechanism 10 refers to a device that can fold the electrode group 20 back and forth in a Z-shape on the stacking platform 12; and the electrode group 20 refers to a combined structure formed by the first electrode 22, the diaphragm 24 and the second electrode 23. In order to ensure that the electrode group 20 can be continuously folded back and forth in a Z-shape to form a laminated structure, the electrode group 20 has a number of continuous and foldable laminated areas 21 along its own length direction, and there is a fold between two adjacent laminated areas 21. Among them, the fold can be set on one side of the electrode group 20, or on two opposite sides of the electrode group 20, that is, double-sided marking. Of course, the concept of the laminated area 21 can also be defined by the fold on the electrode group 20, for example: along the length direction of the electrode group 20, the area between two adjacent folds is the laminated area 21. In addition, it needs to be explained that the folding of the laminated area 21 is actually the folding of the corresponding part of the electrode group 20 in the laminated area 21. For the sake of convenience, it is abbreviated as the folding of the laminated area 21 in the whole text.

[0059] To allow each laminated area 21 to fold back and forth (also understood as folding left and right), the first electrode sheet 22 and the diaphragm 24 can be designed as a continuous strip structure. The second electrode sheet 23 can be die-cut into a structure of the required size and placed one-to-one in each laminated area 21. Furthermore, in two adjacent laminated areas 21, the two second electrode sheets 23 are located on different sides of the electrode assembly 20. The first electrode sheet 22 can be a negative electrode sheet, and the second electrode sheet 23 can be a positive electrode sheet.

[0060] The conveying component 11 refers to a device that provides conveying power for the electrode group 20, which can be a roller structure. For example, the conveying component 11 can include a first roller 111 and a second roller 112 that cooperate with each other, and the electrode group 20 is clamped between the first roller 111 and the second roller 112. At this time, the conveying end 113 of the conveying component 11 acting on the electrode group 20 can be understood as the end of the first roller 111 or the second roller 112 that contacts the electrode group 20. Of course, in some embodiments, the conveying end 113 of the conveying component 11 can also be determined by connecting the center of the circle between the first roller 111 and the second roller 112. The intersection of the connecting line and the first roller 111 or the second roller 112 can also be regarded as the conveying end 113 of the conveying component 11. The folding starting point 26 of the laminated area 21 on the stacking platform 12 refers to the end where the laminated area 21 begins to fold on the stacking platform 12.

[0061] The stacking platform 12 refers to a structure used to support the stacking structure and provide support force for the folding process. For example: during the folding process, the conveying component 11 moves the electrode group 20 toward the stacking platform 12, so that one end of the stacking area 21 contacts the working surface 121 of the stacking platform 12; as the conveying continues, one end of the stacking area 21 uses the folding starting point 26 on the working surface 121 as the folding point, and gradually bends and fits toward the working surface 121.

[0062] When one end of the laminate region 21 is folded with the folding starting point 26 as the folding point, the end of the laminate region 21 will be subjected to a pulling force on the stacking platform 12, causing the end of the adjacent laminate region 21 to bend and warp. For example, in some embodiments, please refer to Figure 3. When a laminate region 21 is folded, the laminate region 21 will be subjected to a pulling force at the folding starting point 26. The pulling force is transmitted through the laminate region 21 to the adjacent laminate region 21, causing the end of the folded laminate region 21 to bend. The bending and warping will cause the gap 1f between two adjacent folds 25 to be abnormal. For example, if the gap 1f is too large, please refer to Figure 4 for details, resulting in poor electrolyte wettability and weak lithium ion kinetics, which makes lithium deposition at the fold 25 easy.

[0063] At this time, if the distance between the folding starting point 26 and the conveying end 113 on the same side is increased, the pulling force of the working surface 121 on the laminated area 21 will be weakened, and the degree of bending and warping of the adjacent and unfolded laminated area 21 will also be reduced. It should be noted that if the conveying component 11 rotates around its own axis, the conveying end 113 on one side will move toward the side of the stacking platform 12; the conveying end 113 on the other side will move away from the side of the stacking platform 12. Therefore, when controlling the rotation of the conveying component 11, the conveying end 113 on that side and the folding starting point 26 should be located on the same side of the axis connecting the conveying component 11 and the stacking platform 12, and the distance between the conveying end 113 and the folding starting point 26 is increased. Among them, the axis connecting the conveying component 11 and the stacking platform 12 can be referred to Figure 2, and the "axis connecting the two axes" is the line between 1h and 1b in Figure 2.

[0064] In step S200, when at least one of the conveying member 11 and the stacking platform 12 is rotated, it is determined whether a laminated area 21 on the stacking platform 12 is being folded. If no laminated area 21 is being folded, bending of one end of the laminated area 21 will not occur, and there is no need to rotate the conveying member 11 and / or the stacking platform 12 about their respective axes.

[0065] It is easy to understand that in order for the laminated area 21 to be folded on the stacking platform 12, the folding starting point 26 of the laminated area 21 should be arranged at an acute angle to the working surface 121 of the stacking platform 12 when the laminated area 21 first contacts the stacking platform 12. This allows for stable folding on the stacking platform 12 by relying on the conveying force of the conveying member 11. To this end, if the distance between the conveying end 113 of the conveying member 11 and the folding starting point 26 of the laminated area 21 is to be increased by rotation, the stacking platform 12 should rotate in the opposite direction to the folding and bending direction of the laminated area 21; alternatively, the conveying member 11 should rotate in the same direction as the folding and bending direction of the laminated area 21.

[0066] For ease of understanding, using Figure 2 as an example, when the laminated area 21 is bent and folded counterclockwise, the stacking platform 12 should rotate clockwise around the first axis 1b; alternatively, the conveying component 11 should rotate counterclockwise around the second axis 1h. When the laminated area 21 is bent and folded clockwise, the stacking platform 12 should rotate counterclockwise around the first axis 1b; alternatively, the conveying component 11 should rotate clockwise around the second axis 1h.

[0067] The first axis 1b and the second axis 1h are the axes of the stacking platform 12 and the conveying member 11, respectively. The first axis 1b and the second axis 1h are respectively arranged relative to each other in the conveying direction X of the electrode assembly 20. For example, the orthographic projection of the second axis 1h on the stacking platform 12 may overlap with the first axis 1b. At the same time, during the folding process, the folding starting point 26 of the laminated area 21 is located on one side of the first axis 1b. Specifically, in some embodiments, the first axis 1b is located at the center of the stacking platform 12, and the second axis 1h is located at the center of the conveying member 11, for example, the second axis 1h is located between the first roller 111 and the second roller 112.

[0068] It should be noted that, in the embodiments of the present application, "the line distance increases" does not mean that the line distance increases continuously during the rotation of the conveying component 11 or the stacking platform 12. Rather, when the conveying component 11 or the stacking platform 12 rotates, the line distance between the conveying end 113 of the conveying component 11 and the folding starting point 26 of the laminated area 21 on the stacking platform 12 will increase over a period of time. For example, as the conveying component 11 or the stacking platform 12 rotates, the line distance between the conveying end 113 of the conveying component 11 and the folding starting point 26 on the laminated area 21 may periodically increase and then decrease. In addition, to facilitate understanding of the "line distance," reference may be made to FIG. 2 . The line distance between the conveying end 113 of the conveying component 11 and the folding starting point 26 of the laminated area 21 on the stacking platform 12 on the same side may be the distance indicated by D in FIG. 2 .

[0069] This design provides space for the folding of the laminated area 21, facilitating stress release during folding, reducing the pulling force exerted by the folding laminated area 21 on the unfolded laminated area 21, and reducing the degree of bending and warping of the laminated area 21 at the fold 25. This reduces the probability of an abnormal gap 1f forming at the fold 25 of the laminated structure, thereby effectively reducing the probability of lithium deposition at the fold 25 of the electrode sheet and improving the quality of the laminated battery.

[0070] According to some embodiments of the present application, referring to FIG. 5 , S200 , the step of controlling the conveying component 11 and / or the stacking platform 12 to rotate around their respective axes, includes:

[0071] S210, control the conveying component 11 and / or the stacking platform 12 to rotate continuously and periodically around their respective axes to execute a rotation strategy, wherein the rotation strategy includes a first step and a second step; wherein the first step includes rotating away from the initial position 1c of the conveying component 11 or the stacking platform 12 along the first direction, and then rotating to the initial position 1c along the second direction, and the second step includes rotating away from the initial position 1c along the second direction, and then rotating to the initial position 1c along the first direction, wherein the first direction is opposite to the second direction.

[0072] Continuously and periodically executing the rotation strategy means that when the conveying component 11 or the stacking platform 12 completes one rotation strategy, it immediately executes another rotation strategy, and the cycle repeats.

[0073] A rotation strategy involves executing the first and second steps within a single cycle. The order in which the first and second steps are executed is not limited; for example, the first and second steps can be executed sequentially, or the second step can be executed first and then the first step. If the conveyor component 11 and the stacking platform 12 are simultaneously controlled to execute the rotation strategy, the conveyor component 11 and the stacking platform 12 will each execute different steps within the rotation strategy. For example, while the stacking platform 12 executes the first step, the conveyor component 11 executes the second step, and so on. The first direction can be clockwise and the second direction counterclockwise, or the first direction can be counterclockwise and the second direction clockwise. Of course, when executing the rotation strategy, the reciprocating cycle of the conveyor component 11 is the same as the reciprocating cycle of the stacking platform 12.

[0074] The initial position 1c refers to the position of the conveying component 11 or the stacking platform 12 when the rotation strategy is not executed. To facilitate the identification of the initial position 1c, the horizontal position of the stacking platform 12 or the conveying component 11 can be used as the initial position 1c.

[0075] When the stacking area 21 is folded on the stacking platform 12, taking the stacking platform 12 being controlled to execute the rotation strategy as an example, please refer to Figure 6, (a) in Figure 6 is a structural schematic diagram corresponding to the pole piece group 20 in some embodiments of the present application when the stacking platform 12 does not execute the rotation strategy during the folding process; (b) in Figure 6 is a structural schematic diagram corresponding to the pole piece group 20 in some embodiments of the present application when the stacking platform 12 rotates clockwise to the extreme position 1g during the folding process; (c) in Figure 6 is a structural schematic diagram corresponding to the pole piece group 20 in some embodiments of the present application when the stacking platform 12 returns to the initial position 1c during the folding process; (d) in Figure 6 is a structural schematic diagram corresponding to the pole piece group 20 in some embodiments of the present application when the stacking platform 12 rotates counterclockwise to the extreme position 1g during the folding process; (e) in Figure 6 is a structural schematic diagram corresponding to the pole piece group 20 in some embodiments of the present application when the stacking platform 12 returns to the initial position 1c during the folding process. First, the stacking platform 12 is rotated clockwise from the initial position 1c to the extreme position 1g, increasing the distance between the conveying component 11 and the stacking platform 12, providing space for the folding of the laminated area 21, facilitating the release of the pulling force on the laminated area 21, and reducing the degree of bending and warping at one end of the laminated area 21. Next, the stacking platform 12 is driven to rotate counterclockwise back to the initial position 1c, so that the laminated area 21 is completely folded on the stacking platform 12; then, the stacking platform 12 is driven to rotate counterclockwise again from the initial position 1c, increasing the distance between the conveying component 11 and the stacking platform 12; finally, the stacking platform 12 is driven to rotate clockwise back to the initial position 1c, so that the other laminated area 21 is also completely folded on the stacking platform 12. Among them, the extreme position 1g refers to the farthest position that the conveying component 11 can reach from the initial position 1c.

[0076] To further improve the folding effect, the rotation strategy can be executed when the stacking section 21 begins to fold on the stacking platform 12, which can also be understood as when the previous stacking section 21 has just completed folding. At the same time, the rotation strategy can also be terminated when the stacking section 21 is completely folded on the stacking platform 12.

[0077] With such a design, during the folding process of the electrode group 20, at least one of the conveying component 11 and the stacking platform 12 is controlled to periodically execute a rotation strategy, providing effective clearance space for the folding process of the stacking area 21, facilitating the release of the force on the stacking area 21, reducing the degree of bending and warping on the stacking area 21, and improving the quality of the stacked battery.

[0078] According to some embodiments of the present application, referring to FIG. 7 , the step of executing the rotation strategy includes:

[0079] S211, when the lamination area 21 is folded along the first direction, controlling the lamination stage 12 to perform the second step;

[0080] S212 , when the lamination area 21 is folded along the second direction, controlling the lamination stage 12 to execute the first step.

[0081] The first direction and the second direction refer to opposite sides of the initial position 1c along a predetermined direction. For ease of understanding, the first direction may be the counterclockwise direction in FIG. 6 , and the second direction may be the clockwise direction in FIG. 6 . When the laminated section 21 rotates counterclockwise on the stacking platform 12 and is folded, the stacking platform 12 performs the second step. For example, the stacking platform 12 first rotates clockwise from the initial position 1c to a predetermined position, and then returns from this position to the initial position 1c. When the laminated section 21 rotates clockwise on the stacking platform 12 and is folded, the stacking platform 12 performs the first step. It first rotates counterclockwise from the initial position 1c to a predetermined position, and then returns from this position to the initial position 1c.

[0082] In this way, the direction in which the stacking platform 12 starts to rotate is set opposite to the folding and bending direction of the stacking area 21, so that the connecting line distance between the conveying end 113 of the conveying component 11 and the folding starting point 26 of the stacking area 21 can be stretched, thereby increasing the space between the conveying component 11 and the stacking platform 12, facilitating stress release, reducing the bending and warping of the folding part 25, and improving the quality of the laminated battery.

[0083] According to some embodiments of the present application, referring to FIG8 , the step of executing the rotation strategy includes:

[0084] S213, when the lamination area 21 is folded along the first direction, controlling the conveying component 11 to perform the first step;

[0085] S214 , when the lamination area 21 is folded along the second direction, control the conveying component 11 to execute the second step.

[0086] For ease of understanding, taking Figure 9 as an example for explanation, the first direction may be the counterclockwise direction in Figure 9, and the second direction may be the clockwise direction in Figure 9. Figure 9 (a) is a structural schematic diagram of the pole piece group 20 in some embodiments of the present application when the conveying component 11 does not execute the rotation strategy during the folding process; Figure 9 (b) is a structural schematic diagram of the pole piece group 20 in some embodiments of the present application when the conveying component 11 rotates counterclockwise to the extreme position 1g during the folding process; Figure 9 (c) is a structural schematic diagram of the pole piece group 20 in some embodiments of the present application when the conveying component 11 returns to the initial position 1c during the folding process; Figure 9 (d) is a structural schematic diagram of the pole piece group 20 in some embodiments of the present application when the conveying component 11 rotates clockwise to the extreme position 1g during the folding process; Figure 9 (e) is a structural schematic diagram of the pole piece group 20 in some embodiments of the present application when the conveying component 11 returns to the initial position 1c during the folding process.

[0087] When the laminated area 21 rotates counterclockwise and is folded on the stacking platform 12, the conveying member 11 performs a first step, for example, the conveying member 11 first rotates counterclockwise from the initial position 1c to a certain position, and then returns from this position to the initial position 1c. When the laminated area 21 rotates clockwise and is folded on the stacking platform 12, the conveying member 11 performs a second step, first rotating clockwise from the initial position 1c to a certain position, and then returning from this position to the initial position 1c.

[0088] In this way, the starting rotation direction of the conveying component 11 is set to be the same as the folding and bending direction of the stacking area 21, so that the connecting line distance between the conveying end 113 of the conveying component 11 and the folding starting point 26 of the stacking area 21 can be stretched, thereby increasing the space between the conveying component 11 and the stacking platform 12, facilitating stress release, reducing the bending and warping of the folding part 25, and improving the quality of the laminated battery.

[0089] According to some embodiments of the present application, the positions passed by the conveying component 11 or the stacking platform 12 when rotating in any direction include an initial position 1c and an extreme position 1g, and an acute angle is formed between the extreme position 1g and the initial position 1c.

[0090] The extreme position 1g refers to the farthest position that the conveyor component 11 or stacking platform 12 can reach from the initial position 1c. When the conveyor component 11 or stacking platform 12 begins executing the rotation strategy, the conveyor component 11 or stacking platform 12 rotates from the initial position 1c to the extreme position 1g and then returns from the extreme position 1g to the initial position 1c. Furthermore, in some embodiments, when the conveyor component 11 or stacking platform 12 rotates to the extreme position 1g, the stacking area 21 stacked on the stacking platform 12 and the adjacent stacking area 21 can be designed to be approximately perpendicular, for example, with an angle of 80° to 90°.

[0091] If the conveying member 11 or stacking platform 12 completes one rotation between the initial position 1c and the extreme position 1g, the stacking platform 12 can complete the folding of one laminated area 21. In this case, the movement of the conveying member 11 or stacking platform 12 and the folding of the laminated area 21 can have different corresponding relationships. For example, when the conveying member 11 or stacking platform 12 rotates from the initial position 1c to the extreme position 1g, the laminated area 21 can complete half of the folding, less than half of the folding, or more than half of the folding.

[0092] To facilitate quantification of the folding amount of the laminated area 21, the conveying amount at the conveying end 113 of the conveying member 11 can be used. For example, when the conveying member 11 or the stacking platform 12 rotates from the initial position 1c to the extreme position 1g, the conveying amount of the electrode assembly 20 conveyed by the conveying end 113 of the conveying member 11 can be half the length of the laminated area 21; or less than or greater than half the length of the laminated area 21; and the remaining length of the laminated area 21 corresponds to the length of the laminated area 21 when the extreme position 1g is rotated to the initial position 1c. To facilitate understanding of the length of the laminated area 21, using Figure 2 as an example, the length of the laminated area 21 can be the dimension represented by L in Figure 2.

[0093] Setting the rotation path of the conveying component 11 or the stacking platform 12 between the initial position 1c and the extreme position 1g makes it easier to associate the reciprocating rotation of the conveying component 11 or the stacking platform 12 with the folding action of the stacking area 21, thereby improving the effective control of the folding process of the electrode group 20.

[0094] According to some embodiments of the present application, referring to FIG. 6 , the angle between the extreme position 1g and the initial position 1c is denoted as θ, wherein when one of the conveying component 11 and the stacking platform 12 is controlled to execute the rotation strategy, 0°<θ≤60°.

[0095] It should be noted that if the conveying component 11 and the stacking platform 12 are both controlled to execute the rotation strategy, the sum of the angles of the conveying component 11 and the stacking platform 12 from the initial position 1c to the extreme position 1g is twice the angle θ. Therefore, in this case, the value range of the angle θ can be narrowed accordingly.

[0096] The size of the angle θ will affect the distance between the conveying end 113 of the conveying component 11 and the folding starting point 26 of the lamination area 21. For example, if the angle θ is too large, the distance between the conveying end 113 of the conveying component 11 and the folding starting point 26 of the lamination area 21 will be too large, resulting in more than two lamination areas 21 being suspended between the conveying component 11 and the stacking platform 12, thereby causing the folding effect of the electrode group 20 to deteriorate; at the same time, the folded lamination area 21 may slip on the stacking platform 12 due to the excessive inclination angle.

[0097] Therefore, the value of the angle θ is controlled to be between 0° and 60°. For example, the value of the angle θ can be, but is not limited to, 10°, 20°, 30°, 40°, 50°, 60°, etc.

[0098] Controlling the angle θ between 0° and 60° facilitates stress release of the electrode assembly 20 during the folding process, thereby improving the quality of the laminated battery; at the same time, it also facilitates improving the stability of the electrode assembly 20 on the stacking platform 12.

[0099] In some embodiments, θ further satisfies the condition: 15°≤θ≤30°.

[0100] The value of θ can also be controlled between 15° and 30°. For example, the value of θ can be, but is not limited to, 15°, 17°, 20°, 22°, 25°, 27°, 28°, 30°, etc.

[0101] The rotation angle from the initial position 1c to the extreme position 1g is further controlled within a range of 15° to 30°, so as to more accurately control the folding process of the electrode assembly 20 and more effectively improve the folding effect of the electrode assembly 20 .

[0102] According to some embodiments of the present application, please refer to Figure 6. When the conveying component 11 and / or the stacking platform 12 rotates from the initial position 1c to the extreme position 1g, the conveying displacement of the conveying end 113 of the conveying component 11 to the pole piece group 20 is controlled to be the first displacement 1a, and the ratio of the first displacement 1a to the length of the stacking area 21 is recorded as γ, where 0.3≤γ≤0.7.

[0103] It is easy to understand that since the conveying member 11 is in a working state during the folding process, when the conveying member 11 or the stacking platform 12 rotates from the initial position 1c to the extreme position 1g, the conveying end 113 of the conveying member 11 also drives the electrode group 20 to be transported toward the side of the stacking platform 12. At this time, when the conveying member 11 or the stacking platform 12 rotates to the extreme position 1g, the conveying amount of the electrode group 20 corresponds to the first displacement 1a.

[0104] In addition, when the conveying component 11 or the stacking platform 12 starts to execute the first step in the rotation strategy, that is, when the conveying component 11 or the stacking platform 12 starts to rotate from the initial position 1c toward the extreme position 1g, one of the stacking areas 21 can be controlled to just start folding or fold shortly on the stacking platform 12.

[0105] γ can take a value between 0.3 and 0.7, for example, γ can be but not limited to 0.3, 0.4, 0.5, 0.6, 0.7, etc. When γ is 0.5, it means that the conveying component 11 has conveyed half of the lamination area 21 of the pole piece group 20. If the conveying component 11 conveys two lamination areas 21 in response to executing a rotation strategy, for example, during the execution of the rotation strategy, when rotating from the initial position 1c to the extreme position 1g, the conveying component 11 conveys half of the lamination area 21; and when returning from the extreme position 1g to the initial position 1c, the conveying component 11 has conveyed the other half of the lamination area 21.

[0106] The ratio of the first displacement 1a to the length of the stacking area 21 is controlled within a range of 0.3 to 0.7, so that the electrode group 20 is transported by at least 0.3 of the stacking area 21 when the conveying component 11 or the stacking platform 12 rotates from the initial position 1c to the extreme position 1g, which is beneficial to reducing the bending and warping of the electrode group 20 at the folding part 25 and improving the quality of the stacked battery.

[0107] According to some embodiments of the present application, γ further satisfies the condition: 0.3≤γ≤0.4.

[0108] γ can take a value between 0.3 and 0.4. For example, γ can be, but is not limited to, 0.3, 0.31, 0.32, 0.33, 0.34, 0.35, 0.36, 0.37, 0.38, 0.39, 0.4, etc.

[0109] Further controlling the ratio of the first displacement 1a to the length of the laminated area 21 within a range of 0.3 to 0.4 is beneficial for further effective control of the folding process of the electrode assembly 20, thereby making the quality of the laminated battery more controllable.

[0110] According to some embodiments of the present application, the step of executing the rotation strategy includes: when the conveying component 11 or the stacking platform 12 rotates from the initial position 1c to the extreme position 1g, controlling the conveying component 11 or the stacking platform 12 to rotate first at a first angular velocity and then at a second angular velocity, wherein the first angular velocity is greater than the second angular velocity.

[0111] When rotating from the initial position 1c to the extreme position 1g, the angular velocity of the conveying member 11 or stacking platform 12 is divided into two stages: first, rotation at a first angular velocity; then, rotation at a second angular velocity, which is relatively slow, to the extreme position 1g. Considering that the laminated area 21 is most susceptible to bending and warping during the folding process, most of the time it is immediately after folding, this embodiment controls the first angular velocity to be greater than the second angular velocity, allowing the conveying member 11 or stacking platform 12 to rotate at a relatively fast angular velocity. This allows the distance between the conveying member 11 and stacking platform 12 to be quickly increased, resulting in a faster angular velocity response to stress release.

[0112] When the conveying member 11 or stacking platform 12 rotates at the first angular velocity and when it rotates at the second angular velocity between the initial position 1c and the extreme position 1g can be determined based on the actual folding process. For example, the conveying member 11 or stacking platform 12 rotates at the first angular velocity for 1 / 3 to 1 / 2 of the entire time period, and at the second angular velocity for the remaining time. The entire time period described above refers to the time it takes for the conveying member 11 or stacking platform 12 to rotate from the initial position 1c to the extreme position 1g.

[0113] To facilitate an intuitive understanding of the rotation trajectory of the stacking platform 12, the angle between the initial position 1c and the extreme position 1g can be assigned a value of 1. The specific rotation angle amplitude curve of the stacking platform 12 in this case can be found in Figure 10. As can be seen, on one side of the initial position 1c, the stacking platform 12 first rotates a distance from the initial position 1c at a first angular velocity, then rotates to the extreme position 1g at a second angular velocity; then returns to the initial position 1c at a constant speed; then, on the other side of the initial position 1c, the stacking platform 12 rotates a distance from the initial position 1c at the first angular velocity, then rotates to the extreme position 1g at the second angular velocity; finally, it returns to the initial position 1c at a constant speed, thus completing one rotation strategy.

[0114] The first angular velocity is controlled to be greater than the second angular velocity, so that the conveying component 11 or the stacking platform 12 can translate faster at the beginning of folding, which is conducive to quickly increasing the connecting distance between the conveying component 11 and the stacking platform 12, so that the stress in the folding process is quickly released, which is convenient for further improving the quality of the laminated battery.

[0115] According to some embodiments of the present application, the ratio of the first angular velocity to the second angular velocity is denoted as β, where 1.5≤β≤2.5.

[0116] The ratio between the first and second angular velocities should be designed appropriately. If the difference between the first and second angular velocities is small, the total angle remains constant, i.e., the angle between the initial position 1c and the extreme position 1g is fixed. Therefore, if the difference between the two angular velocities is small, the distance between the conveyor component 11 and the stacking platform 12 cannot be quickly increased during the initial rotation, resulting in a slow angular velocity response to stress release. If the difference between the first and second angular velocities is too large, the conveyor component 11 or the stacking platform 12 will need to switch between two significantly different angular velocities, which is detrimental to control stability.

[0117] To this end, the ratio of the first angular velocity to the second angular velocity can be controlled between 1.5 and 2.5. For example, β can be but is not limited to 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, 2.1, 2.2, 2.3, 2.4, 2.5, etc.

[0118] Controlling the ratio of the first angular velocity to the second angular velocity within a range of 1.5 to 2.5 can improve the response angular velocity to stress release during the folding process and thus improve the folding effect. At the same time, it can also effectively take into account the rotation control of the conveying component 11 or the stacking platform 12, so that the conveying component 11 or the stacking platform 12 can rotate stably when executing the rotation strategy.

[0119] According to some embodiments of the present application, β further satisfies the condition: 1.8≤β≤2.2.

[0120] The ratio of the first angular velocity to the second angular velocity may also be controlled to be between 1.8 and 2.2. For example, β may be, but is not limited to, 1.8, 1.9, 2.0, 2.1, 2.2, and the like.

[0121] In this way, the ratio of the first angular velocity to the second angular velocity is further controlled within a range of 1.8 to 2.2, so that the angular velocity response to stress release during the folding process is better; at the same time, the rotation of the conveying component 11 or the stacking platform 12 can be more stably controlled.

[0122] According to some embodiments of the present application, when the conveying component 11 and / or the stacking platform 12 completes the rotation strategy, the conveying displacement of the conveying end 113 of the conveying component 11 to the pole piece group 20 is at least the length of two stacking areas 21.

[0123] When the conveying component 11 and / or the stacking platform 12 completes the rotation strategy, the conveying component 11 may output two laminated areas 21, or may output more than three laminated areas 21. Specifically, in some embodiments, when the conveying component 11 and / or the stacking platform 12 completes the rotation strategy, the conveying end 113 of the conveying component 11 conveys the displacement of the electrode assembly 20 by the length of two laminated areas 21. At the same time, when the conveying component 11 or the stacking platform 12 completes the first step or the second step, the conveying end 113 of the conveying component 11 conveys the displacement of the electrode assembly 20 by the length of one laminated area 21.

[0124] In this way, the cycle of the rotation strategy is associated with the conveying cycle of the conveying component 11, so that the folding quality of the electrode group 20 is more controllable and the consistency of the product is better.

[0125] According to some embodiments of the present application, please refer to Figure 6, in the step of executing the rotation strategy, it includes: after each execution of the first step or the second step, controlling the conveying component 11 and / or the stacking platform 12 to move a preset displacement 1d in a direction away from each other.

[0126] As folding continues, the number of stacked sections 21 on the stacking platform 12 increases, and the spacing between the stacking platform 12 and the conveying member 11 decreases. This gradually compresses the folding space provided for the stacking sections 21. To this end, when the conveying member 11 and / or the stacking platform 12 execute the rotation strategy, the conveying member 11 and / or the stacking platform 12 are controlled to move in a direction away from each other by a predetermined displacement amount 1d. This increases the spacing between the conveying member 11 and the stacking platform 12, partially or completely compensating for the space between the conveying member 11 and the stacking platform 12 that is compressed due to the increased folding thickness, thereby ensuring stable operation of the folding process. The phrase "away from each other" refers to the distance between the conveying member 11 and the stacking platform 12.

[0127] In addition, there are various control methods for controlling the conveying components 11 and / or the stacking platform 12 to move in directions away from each other, such as: when the conveying components 11 and / or the stacking platform 12 execute the first step or the second step, controlling the conveying components 11 and / or the stacking platform 12 to move synchronously in directions away from each other; or, after the conveying components 11 and / or the stacking platform 12 execute the first step or the second step, controlling the conveying components 11 and / or the stacking platform 12 to move as a whole in directions away from each other.

[0128] It should be noted that controlling the conveying component 11 and / or the stacking platform 12 to move in a direction away from each other by a preset displacement amount 1d means: if one of the conveying component 11 and the stacking platform 12 is controlled to move in a direction away from each other, the movement amount of the conveying component 11 or the stacking platform 12 is the preset displacement amount 1d; if both the conveying component 11 and the stacking platform 12 are controlled to move in a direction away from each other, the sum of the movement amounts of the conveying component 11 and the stacking platform 12 is the preset displacement amount 1d.

[0129] Such a design can effectively make up for the space compressed due to the increase in the number of folding times, making it easier for the electrode assembly 20 to be folded; at the same time, it can also facilitate the stress release of the electrode assembly 20 during the folding process, thereby improving the quality of the laminated battery.

[0130] According to some embodiments of the present application, referring to FIG. 6 , the ratio of the preset displacement 1d to the thickness of the pole piece group 20 in the lamination area 21 is denoted as α, where 1≤α≤5.

[0131] The thickness of the electrode assembly 20 in the laminated region 21 refers to the sum of the thicknesses of the first electrode 22, the second electrode 23, and the separator 24 in the laminated region 21. The thickness of the electrode assembly 20 in the laminated region 21 can be determined based on the actual structural design of the laminated region 21. For example, in the laminated region 21, the electrode assembly 20 can include a first electrode 22, separators 24 disposed on two opposite sides of the first electrode 22, and a second electrode 23 disposed on one of the separators 24. In this case, the thickness of the electrode assembly 20 in the laminated region 21 can be the sum of the thicknesses of the first electrode 22, the second electrode 23, and the two separators 24.

[0132] α can be a value between 1 and 5, for example, α can be, but is not limited to, 1, 1.2, 1.5, 2.0, 2.5, 3, 4, 5, etc. When α is 1, the conveying component 11 or the stacking platform 12 moves in a direction away from each other by the thickness of one electrode group 20; when α is 5, the conveying component 11 or the stacking platform 12 moves in a direction away from each other by the thickness of five electrode groups 20.

[0133] The ratio of the preset displacement 1d to the thickness of the electrode group 20 in the stacking area 21 is controlled within a range of 1 to 5, so that the conveying component 11 or the stacking platform 12 can be appropriately displaced backward after folding, leaving a reasonable space for the electrode group 20 between the conveying component 11 and the stacking platform 12, thereby achieving a stable and effective folding process.

[0134] According to some embodiments of the present application, α further satisfies the condition: 2≤α≤3.

[0135] α can take a value between 2 and 3, for example, the value of α can be, but is not limited to, 2, 2.2, 2.4, 2.6, 2.8, 3, etc.

[0136] The value of α is further controlled between 2 and 3, so that after each folding, the space between the conveying component 11 and the stacking platform 12 is more reasonably controlled, thereby making the folding process of the electrode group 20 on the stacking platform 12 more stable.

[0137] According to some embodiments of the present application, referring to FIG. 11 , before the step of controlling the conveying component 11 and / or the stacking platform 12 to rotate around their respective axes in S200 , the following steps may be further included:

[0138] The minimum distance between the conveying end 113 of the conveying component 11 and the working surface 121 of the stacking platform 12 is controlled to be the initial distance 1e, wherein the ratio of the initial distance 1e to the length of the stacking area 21 is denoted as λ, 1.2≤λ≤2.

[0139] The minimum distance between the conveying end 113 and the working surface 121 refers to the length of the perpendicular line segment obtained by drawing a perpendicular line from the conveying end 113 to the working surface 121, which is the initial distance 1e. For details, please refer to the distance represented by 1e in Figure 11.

[0140] The size of the initial spacing 1e will affect the folding effect of the electrode group 20 on the stacking platform 12. For example, if the initial spacing 1e is less than the length of a laminated area 21, part of the laminated area 21 will still be on the conveying component 11, while the other part has already been folded on the stacking platform 12. This will make it more difficult to release the stress on the laminated area 21 and prevent normal Z-shaped reciprocating folding. If the initial spacing 1e is too large, it will cause more than two laminated areas 21 to be suspended between the conveying component 11 and the stacking platform 12. This will easily cause the folding direction to become disordered during reciprocating folding; at the same time, it will also reduce folding efficiency.

[0141] To this end, the ratio of the initial spacing 1e to the length of the lamination area 21 is controlled between 1.2 and 2. For example, λ can be, but is not limited to, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2, etc.

[0142] With this design, the ratio of the initial spacing 1e to the length of the lamination area 21 is controlled between 1.2 and 2, so that there is a suspended lamination area 21 between the conveying component 11 and the lamination platform 12, so that the folding process can be carried out stably; it is also beneficial to improve the folding efficiency.

[0143] According to some embodiments of the present application, λ further satisfies the condition: 1.3≤λ≤1.6.

[0144] The ratio of the initial spacing 1e to the length of the lamination area 21 is controlled between 1.3 and 1.6. For example, λ can be, but is not limited to, 1.3, 1.35, 1.4, 1.45, 1.5, 1.55, 1.6, etc.

[0145] In this way, the ratio of the initial spacing 1e to the length of the lamination area 21 is further controlled between 1.3 and 1.6, which facilitates more precise control of the folding of the electrode assembly 20 and further improves the stability and folding efficiency of the folding process.

[0146] According to some embodiments of the present application, in response to the step of folding the laminated area 21 on the stacking platform 12, it includes: controlling the conveying displacement of the conveying end 113 of the conveying component 11 to the pole piece group 20 to be a second displacement, wherein the ratio of the second displacement to the length of the laminated area 21 is recorded as ε, 2≤ε≤10.

[0147] The conveying displacement of the electrode group 20 by the conveying end 113 of the conveying component 11 can also be understood as the displacement of the electrode group 20 toward the stacking platform 12 under the action of the conveying component 11. Under the premise that the initial spacing 1e is controlled between 1.2 and 2, the conveying displacement of the electrode group 20 by the conveying end 113 of the conveying component 11 is controlled between 2 and 10, so that at least one stacking area 21 has been or begins to be folded on the stacking platform 12. For example, ε can be but is not limited to 2, 3, 4, 5, 6, 7, 8, 9, 10, etc.

[0148] With this design, the conveying displacement of the conveying end 113 of the conveying component 11 to the electrode group 20 is controlled between 2 and 10, so that at least one stacking area 21 has been folded on the stacking platform 12, which facilitates the stress release of the folding stacking area 21, reduces the bending and warping of the folding part 25, and improves the quality of the laminated battery.

[0149] According to some embodiments of the present application, ε further satisfies the condition: 2.1≤ε≤2.9.

[0150] On the premise that the initial spacing 1e is controlled between 1.2 and 2, the conveying displacement of the conveying end 113 of the conveying component 11 to the pole piece group 20 is controlled between 2.1 and 2.9, which can reduce the number of folds of the stacking area 21 on the stacking platform 12 before the rotation strategy is executed.

[0151] The conveying displacement ε of the conveying end 113 of the conveying component 11 to the electrode assembly 20 can be controlled between 2.1 and 2.9. For example, ε can be but is not limited to 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, etc.

[0152] The conveying displacement of the conveying end 113 of the conveying component 11 to the electrode group 20 is further controlled between 2.1 and 2.9, reducing the number of folds of the stacking area 21 on the stacking platform 12 before the rotation strategy is executed, so that most of the folding processes on the electrode group 20 can be improved by the rotation strategy, further improving the quality of the stacked battery.

[0153] According to some embodiments of the present application, please refer to FIG12 . The present application provides a pole piece folding control device, which adopts any of the pole piece folding control methods described above, and includes: a response module 200 and an execution module 300. The response module 200 is used to obtain the folding status of the lamination area 21 on the stacking platform 12 and feedback a signal; the execution module 300 is used to control the operation of the conveying component 11 and can control the conveying component 11 and / or the stacking platform 12 to rotate around their respective axes based on the signal feedback from the response module 200.

[0154] The response module 200 refers to a device that can obtain the execution timing of the movement of the conveying component 11 or the stacking platform 12. For example, the response module 200 can be selected as a displacement sensing module to obtain the conveying displacement of the conveying component 11 to the pole piece group 20. For example, if the obtained conveying displacement is 2.1~2.9, a signal is fed back to the execution module 300; or, the response module 200 can be a visual module, such as a CCD, etc., which feeds back a signal to the execution module 300 when information about the folding action on the stacking platform 12 is obtained.

[0155] The execution module 300 refers to a device that can control the operation of the conveying component 11 and the rotation of the conveying component 11 or the stacking platform 12, for example, it can be a single chip microcomputer, an electronic control unit, etc.

[0156] The aforementioned electrode folding control device employs the aforementioned electrode folding control method, utilizing the response module 200 to provide a judgment opportunity for the execution module 300 to control the rotation of the conveying component 11 or the stacking platform 12. This provides space for the folding of the stacking area 21, facilitating stress release during folding, reducing the pulling force exerted by the folding stacking area 21 on the unfolded stacking area 21, and reducing the degree of bending and warping of the stacking area 21 at the folding point 25. This reduces the probability of an abnormal gap 1f forming at the folding point 25 of the stacked structure, thereby effectively reducing the probability of lithium deposition at the folding point 25 of the electrode, thereby improving the quality of the stacked battery.

[0157] According to some embodiments of the present application, a pole piece folding device 100 is provided. The pole piece folding device 100 includes a pole piece folding mechanism 10 and a driving mechanism 30. The pole piece folding mechanism 10 includes a stacking platform 12 and a conveying component 11 for conveying a pole piece group 20 and folding the pole piece group 20 back and forth on the stacking platform 12; the driving mechanism 30 is used to drive the conveying component 11 and / or the stacking platform 12 to rotate around their respective axes.

[0158] The electrode folding mechanism 10 is a device that can fold the electrode assembly 20 back and forth in a Z-shape on the stacking platform 12. The electrode assembly 20 is a composite structure formed by the first electrode 22, the separator 24, and the second electrode 23. To ensure that the electrode assembly 20 can be continuously folded back and forth in a Z-shape to form a laminated structure, the electrode assembly 20 has several continuous and foldable laminated sections 21 along its length, with folds between adjacent laminated sections 21. The folds can be provided on one side of the electrode assembly 20 or on two opposite sides of the electrode assembly 20, i.e., double-sided markings.

[0159] The conveying component 11 refers to a device that provides conveying power for the electrode group 20, which can be a roller structure. For example, the conveying component 11 can include a first roller 111 and a second roller 112 that cooperate with each other, and the electrode group 20 is clamped between the first roller 111 and the second roller 112. At this time, the conveying end 113 of the conveying component 11 acting on the electrode group 20 can be understood as the end of the first roller 111 or the second roller 112 that contacts the electrode group 20. Of course, in some embodiments, the conveying end 113 of the conveying component 11 can also be determined by connecting the center of the circle between the first roller 111 and the second roller 112. The intersection of the connecting line and the first roller 111 or the second roller 112 can also be regarded as the conveying end 113 of the conveying component 11. Among them, one of the first roller 111 and the second roller 112 can be an active roller and the other can be a driven roller; of course, both the first roller 111 and the second roller 112 can be active rollers.

[0160] The stacking platform 12 refers to a structure used to support the stacking structure and provide support force for the folding process. For example, during the folding process, the conveying component 11 moves the electrode group 20 toward the stacking platform 12, so that one end of the stacking area 21 contacts the working surface 121 of the stacking platform 12; as the conveying continues, one end of the stacking area 21 uses the contact point on the working surface 121 as the folding starting point 26, and gradually bends and fits toward the working surface 121.

[0161] The driving mechanism 30 refers to a device that provides power for the rotation of the conveying component 11 or the stacking platform 12. For example, it can be but is not limited to a motor, or it can be a combination of a motor and a transmission mechanism, such as a combination of a motor and a gear set, a combination of a motor and a belt, etc.

[0162] In addition, it should be noted that the pole piece folding device 100 of the present application can also adopt the pole piece folding control method proposed in any of the above embodiments.

[0163] The electrode folding device 100 described above drives the electrode group 20 toward the stacking platform 12 through the conveying component 11 during the folding process of the electrode group 20. When a laminated area 21 begins to be folded or has already been folded on the stacking platform 12, the driving mechanism 30 drives at least one of the conveying component 11 and the stacking platform 12 to rotate around their respective axes, so that the distance between the conveying end 113 of the conveying component 11 and the folding starting point 26 of the stacking platform 12 is stretched. This can provide space for the folding of the laminated area 21, facilitate its stress release during folding, reduce the pulling force of the laminated area 21 in the folding state on the laminated area 21 that has not yet been folded, and reduce the degree of bending and warping of the laminated area 21 at the folding part 25. At this time, the probability of the laminate structure generating an abnormal gap 1f at the folding part 25 is reduced, thereby effectively reducing the probability of lithium deposition of the electrode at the folding part 25, thereby improving the quality of the laminated battery.

[0164] According to some embodiments of the present application, the present application provides a battery production system, which includes the above-mentioned pole piece folding device 100.

[0165] According to some embodiments of the present application, please refer to Figures 1 to 12. The present application provides a method for controlling the folding of a pole piece. During the folding process, the pole piece group 20 starts to move and is input into the double rollers. At this time, the stacking table 12 does not move, and the double rollers continuously rotate relative to each other to transport the pole piece group 20 downward. The initial spacing 1e between the double rollers and the stacking table 12 is about 1.2 to 2 lengths of the stacking area 21. After the double rollers have transported 2.1 to 2.9 lengths of the stacking area 21 downward, the stacking table 12 starts to rotate clockwise or counterclockwise at the same time, increasing the spacing between the double rollers and the stacking table 12, resulting in a gap, reducing the bending of the pole piece at the exit of the double rollers, and reducing the pulling force at the corner. Subsequently, after the double rollers continue to convey the length of 0.3 to 0.7 lamination areas 21, the stacking platform 12 rotates to the left / right stop point (the maximum rotation angle is 0 to 60°). Then, the stacking platform 12 begins to reset and returns to the initial position 1c; then, the stacking platform 12 rotates in the other direction, and then returns to the initial position 1c again (the stacking platform 12 rotates for one cycle, which corresponds to the length of two lamination areas 21 conveyed by the double rollers). After completing one rotation cycle, the stacking platform 12 begins to move downward until the lamination is completed. It should be noted that each time the stacking platform 12 completes a rotation cycle, it will synchronously move downward by the thickness of about 1 to 5 pole piece groups 20 in the lamination areas 21.

[0166] The technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above-mentioned embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0167] The above-described embodiments merely represent several implementation methods of the present application. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that a person of ordinary skill in the art may make various modifications and improvements without departing from the spirit of the present application, and these modifications and improvements fall within the scope of protection of the present application. Therefore, the scope of protection of the present patent application shall be determined by the appended claims.

Claims

1. A method for controlling the folding of a pole piece, wherein a pole piece folding mechanism (10) comprises a stacking platform (12) and a conveying component (11) for conveying a pole piece group (20), wherein: The electrode group (20) has a plurality of lamination areas (21) along its length direction, and the lamination areas (21) have a folding starting point (26) on the stacking platform (12); the conveying component (11) comprises a first roller (111) and a second roller (112) located on both sides of the electrode group (20); the ends of the first roller (111) and the second roller (112) respectively contacting the electrode group (20) are both conveying ends (113), and the axis of the conveying component (11) is located on a line connecting the two conveying ends (113); The pole piece folding control method comprises the following steps: Controlling the conveying component (11) to drive the electrode group (20) to be conveyed toward the stacking platform (12); In response to the lamination area (21) being folded on the stacking platform (12), the conveying component (11) and / or the stacking platform (12) are controlled to rotate around their respective axes so that the distance between the conveying end (113) located on the same side of the axis line connecting the conveying component (11) and the stacking platform (12) and the folding starting point (26) is increased.

2. The pole piece folding control method according to claim 1, wherein: The step of controlling the conveying component (11) and / or the stacking platform (12) to rotate around their respective axes comprises: The conveying component (11) and / or the stacking platform (12) are controlled to rotate continuously and periodically around their respective axes to execute a rotation strategy, wherein the rotation strategy includes a first step and a second step; wherein the first step includes rotating away from an initial position (1c) of the conveying component (11) or the stacking platform (12) along a first direction; and rotating to the initial position (1c) along a second direction; and the second step includes rotating away from the initial position (1c) along the second direction; and rotating to the initial position (1c) along the first direction, wherein the first direction is opposite to the second direction.

3. The pole piece folding control method according to claim 2, wherein: The steps of executing the rotation strategy include: When the lamination area (21) is folded along the first direction, controlling the folding platform (12) to perform the second step; When the lamination area (21) is folded along the second direction, the lamination platform (12) is controlled to perform the first step.

4. The pole piece folding control method according to claim 2 or 3, wherein: The steps of executing the rotation strategy include: When the lamination area (21) is folded along the first direction, controlling the conveying component (11) to perform the first step; When the lamination area (21) is folded along the second direction, the conveying component (11) is controlled to perform the second step.

5. The pole piece folding control method according to any one of claims 2 to 4, wherein: The positions passed by the conveying component (11) or the stacking platform (12) when rotating in any direction include the initial position (1c) and the limit position (1g), and the limit position (1g) is arranged at an acute angle with the initial position (1c).

6. The pole piece folding control method according to claim 5, wherein: The angle between the extreme position (1g) and the initial position (1c) is denoted as θ, wherein, when one of the conveying member (11) and the stacking table (12) is controlled to execute a rotation strategy, 0°<θ≤60°.

7. The pole piece folding control method according to claim 6, wherein: θ also satisfies the condition: 15°≤θ≤30°.

8. The pole piece folding control method according to any one of claims 5 to 7, wherein: When the conveying component (11) and / or the stacking platform (12) rotates from the initial position (1c) to the extreme position (1g), the conveying displacement of the conveying end (113) of the conveying component (11) to the pole piece group (20) is controlled to be a first displacement (1a), and the ratio of the first displacement (1a) to the length of the stacking area (21) is denoted as γ, wherein 0.3≤γ≤0.

7.

9. The pole piece folding control method according to claim 8, wherein: γ also satisfies the condition: 0.3≤γ≤0.

4.

10. The pole piece folding control method according to any one of claims 5 to 9, wherein: The steps of executing the rotation strategy include: When the conveying component (11) or the stacking platform (12) rotates from the initial position (1c) to the extreme position (1g), the conveying component (11) or the stacking platform (12) is controlled to rotate first at a first angular velocity and then at a second angular velocity, wherein the first angular velocity is greater than the second angular velocity.

11. The pole piece folding control method according to claim 10, wherein: The ratio of the first angular velocity to the second angular velocity is denoted as β, wherein 1.5≤β≤2.

5.

12. The pole piece folding control method according to claim 11, wherein: β also satisfies the condition: 1.8≤β≤2.

2.

13. The pole piece folding control method according to any one of claims 2 to 12, wherein: When the conveying component (11) and / or the stacking platform (12) have completed the rotation strategy, the conveying displacement of the conveying end (113) of the conveying component (11) to the pole piece group (20) is at least the length of two stacking areas (21).

14. The pole piece folding control method according to any one of claims 2 to 13, wherein: The steps of executing the rotation strategy include: Each time the first step or the second step is performed, the conveying component (11) and / or the stacking platform (12) are controlled to move in a direction away from each other by a preset displacement amount (1d).

15. The pole piece folding control method according to claim 14, wherein: The ratio of the preset displacement (1d) to the thickness of the pole piece group (20) in the lamination area (21) is denoted as α, wherein 1≤α≤5.

16. The pole piece folding control method according to claim 15, wherein: α also satisfies the condition: 2≤α≤3.

17. The pole piece folding control method according to any one of claims 1 to 16, wherein: Before the step of controlling the conveying component (11) and / or the stacking platform (12) to rotate around their respective axes, the method further comprises: The minimum distance between the conveying end (113) of the conveying component (11) and the working surface (121) of the stacking platform (12) is controlled to be an initial distance (1e), wherein the ratio of the initial distance (1e) to the length of the stacking area (21) is denoted as λ, 1.2≤λ≤2.

18. The pole piece folding control method according to claim 17, wherein: λ also satisfies the condition: 1.3≤λ≤1.

6.

19. The pole piece folding control method according to claim 17 or 18, wherein: In response to the step of folding the laminated area (21) on the stacking platform (12), the step comprises: The conveying displacement of the conveying end (113) of the conveying component (11) to the pole piece group (20) is controlled to be a second displacement, wherein the ratio of the second displacement to the length of the lamination area (21) is denoted as ε, 2≤ε≤10.

20. The pole piece folding control method according to claim 19, wherein: ε also satisfies the condition: 2.1≤ε≤2.

9.

21. A pole piece folding control device, using the pole piece folding control method according to any one of claims 1 to 20, the pole piece folding control device comprising: A response module (200) is used to obtain the folding status of the laminated area (21) on the stacking platform (12) and to feed back a signal; The execution module (300) is used to control the operation of the conveying component (11), and can control the conveying component (11) and / or the stacking platform (12) to rotate around their respective axes according to the signal fed back by the response module (200).

22. A pole piece folding device, the pole piece folding device comprising: A pole piece folding mechanism (10) comprises a stacking platform (12) and a conveying component (11) for conveying a pole piece group (20) and reciprocatingly folding the pole piece group (20) on the stacking platform (12); The driving mechanism (30) is used to drive the conveying component (11) and / or the stacking platform (12) to rotate around their respective axes.

23. A battery production system, comprising the pole piece folding device according to claim 22.

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