Supporting device of battery cell shaping mechanism, battery cell shaping mechanism and battery cell processing method
By using the support device and method of the cell shaping mechanism, the problem of electrode wrinkling in the large cell winding process has been solved, the cell shape has been well maintained, the product yield and mass production feasibility have been improved, and the operation is convenient.
Patent Information
- Application Number
- CN202510966757.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-07-14
- Publication Date
- 2025-10-21
AI Technical Summary
The large-cell winding process has the problem of electrode wrinkling, especially the wrinkling of the outermost negative electrode surface and the negative electrode at the corner of the innermost circle, which leads to poor cell shape and makes it difficult to achieve mass production.
The support device of the battery cell shaping mechanism includes a base, first and second supports and a telescopic intermediate plate. By using the intermediate plate to support the middle of the battery cell during the cold pressing and hot pressing processes, and in conjunction with the movement of the pressure plate, the battery cell is ensured to have a shape with a raised middle and drooping sides, thus solving the problem of electrode wrinkling.
It effectively solves the problem of electrode wrinkling in the large battery cell winding process, improves product yield, reduces the wrinkling ratio, and enhances the feasibility of mass production and the ease of equipment operation.
Smart Images
Figure CN120824441A_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the field of batteries, and specifically provides a support device for a battery cell shaping mechanism, a battery cell shaping mechanism, and a battery cell processing method. Background Art
[0002] With the rapid development of new energy vehicles and the growing demand for energy storage, lithium-ion batteries have become the current main product due to their excellent performance. Among them, square batteries are their important product type.
[0003] Prismatic batteries primarily consist of a housing, a cell, and an electrolyte. The cell is made from a positive electrode, a negative electrode, and a separator through a winding or lamination process. The winding process involves wrapping the positive and negative electrodes and the separator together in a specific pattern, followed by gluing and cold pressing to form a cell. The lamination process involves stacking the cathode and cathode electrodes and the separator in a specific pattern, followed by gluing to form a cell.
[0004] For smaller batteries (such as 280Ah, size 72173), the winding process and the stacking process do not have much difference in their impact on the performance of the battery cell, but winding has huge advantages in efficiency and one-time investment cost. Naturally, for large batteries (such as 530Ah, size 72274), if the process problems of the large battery cell winding process can be solved, then large battery cell winding is likely to become an industry trend in the future. In fact, in the past two years, various leading companies have been conducting relevant verifications on the future direction of large battery cells, but so far they have not completely overcome the relevant process difficulties, so that large battery cells have not been mass-produced.
[0005] During the winding verification process, the main difficulty in the large battery cell process is the wrinkling problem of the electrode, which is mainly manifested in the wrinkles on the surface of the outermost negative electrode caused by cold pressing or hot pressing after the winding is completed, and the wrinkles on the negative electrode at the first fold corner of the innermost circle after cold pressing.
[0006] Accordingly, the art requires a new supporting device, battery cell shaping mechanism and battery cell processing method to solve the problem of electrode wrinkles in the winding core. Application Contents
[0007] The present application aims to solve the above-mentioned technical problem, namely, to solve the problem of pole piece wrinkles in the winding core.
[0008] The present application provides a support device for a battery cell shaping mechanism, comprising: a base, with a first support body and a second support body arranged at intervals on the top, the first support body and the second support body being used to support both sides of the battery cell; a tray assembly, comprising a telescopic member and an intermediate tray, the intermediate tray being used to support the middle part of the battery cell, the intermediate tray being telescopically arranged up and down between the first support body and the second support body through the telescopic member, and having an extended position protruding vertically from the first support body and the second support body.
[0009] In an optional technical solution of the support device of the above-mentioned battery cell shaping mechanism, when the intermediate support plate is in the retracted position, it is flush with the upper surfaces of the first support body and the second support body.
[0010] In an optional technical solution of the supporting device of the above-mentioned battery cell shaping mechanism, the entire upper surfaces of the first supporting body, the intermediate supporting plate and the second supporting body are covered with a protective film.
[0011] In the optional technical solution of the support device of the above-mentioned battery cell shaping mechanism, the telescopic member is configured as an elastic member or a driving mechanism; and / or the base has support seats on opposite sides, and the intermediate support plate has connecting arms on opposite sides, and the connecting arms on both sides are arranged in a one-to-one correspondence with the support seats on both sides, and the telescopic member is provided between the connecting arm and the support seat on each side; and / or a first limiting member is provided on the base, and a second limiting member is provided on the intermediate support plate, and the first limiting member and the second limiting member are limitedly matched to limit the extension height of the intermediate support plate.
[0012] In an optional technical solution of the support device of the above-mentioned battery cell shaping mechanism, a heating element is installed in at least one of the first support body, the intermediate support plate and the second support body.
[0013] On the other hand, the present application also provides a battery cell shaping mechanism, comprising the support device described in any of the above embodiments, and also comprising an upper pressure plate, which is arranged opposite to the support device and is arranged to be able to approach and move away from the support device.
[0014] On the other hand, the present application also provides a battery cell processing method, which adopts the above-mentioned battery cell shaping mechanism, and the method includes: in the cold pressing and / or hot pressing process, placing the middle part of the target battery cell on the middle support plate in the extended position; after placement, controlling the upper pressure plate to move toward the support device until the middle support plate retracts.
[0015] In an optional technical solution of the above-mentioned battery cell processing method, before the step of "placing the middle part of the target battery cell on the middle support plate in the extended position", the method also includes: when the width of the target battery cell is greater than or equal to the preset width, based on the width and thickness of the target battery cell, adjusting the width and extended height of the middle support plate so that after the target battery cell is placed on the supporting device, the middle part of the target battery cell can protrude from both sides of the target battery cell.
[0016] In the optional technical solution of the above-mentioned battery cell processing method, the method also includes: in the winding process, adjusting the pressure of the embossing roller to a pressure that makes the spacing between the pole pieces of the winding core equal to a preset gap, so as to emboss the pole pieces; wherein, the preset gap is determined based on the thickness difference before and after the winding of the positive pole piece, the thickness difference before and after the winding of the negative pole piece, and the spacing between the pole pieces of the original winding core.
[0017] In the optional technical solution of the above-mentioned battery cell processing method, the method also includes: in the formation process, using a clamp to apply pressure to both sides of the target battery cell; and / or the spacing between the pole pieces of the winding core of this method and / or the spacing between the pole pieces of the original winding core is obtained based on the misalignment of the pole ears.
[0018] Those skilled in the art can understand that the supporting device of the battery cell shaping mechanism of the present application includes a base and a tray assembly, the tray assembly includes a telescopic member and an intermediate tray, the top of the base is provided with a first support body and a second support body arranged at intervals, the first support body and the second support body are used to support both sides of the battery cell; the intermediate tray is used to support the middle part of the battery cell, the intermediate tray can be telescopically arranged up and down between the first support body and the second support body through the telescopic member, and has an extended position protruding vertically from the first support body and the second support body.
[0019] After the core is flattened, the middle of the battery cell is placed on the middle support plate of the support device during the cold pressing process and / or hot pressing process to ensure that the battery cell is in a shape with a bulge in the middle and drooping on both sides. When the upper pressure plate of the battery cell shaping mechanism descends, it will first contact the middle part of the battery cell. Then, during the downward pressing process, the telescopic part contracts, and the middle support plate slowly descends and retracts under pressure. After retraction, the upper pressure plate can be pressed down with normal pressure. Under the action of the first support body and the second support body, pressure can also be applied to both sides of the battery cell to perform cold pressing and / or hot pressing on the battery cell as a whole, ensuring that the battery cell is in good shape throughout the process. This solution can solve the problem of wrinkles on the surface of the outermost negative pole and the problem of wrinkles on the negative pole at the innermost corner (sample size exceeds 2000). BRIEF DESCRIPTION OF THE DRAWINGS
[0020] The preferred embodiments of the present application are described below with reference to the accompanying drawings, in which:
[0021] Figure 1It is a three-dimensional diagram of the supporting device of the battery cell shaping mechanism of the present application;
[0022] Figure 2 It is a top view of the supporting device of the battery cell shaping mechanism of the present application;
[0023] Figure 3 This is a simplified structural diagram of the battery cell shaping mechanism of the present application;
[0024] Figure 4 It is a structural diagram of the battery cell;
[0025] Figure 5 This is the main flow chart of the battery cell processing method of the present application;
[0026] Figure 6 This is a possible logic diagram of the battery cell processing method of the present application.
[0027] Description of reference numerals:
[0028] 1-base; 11-first support body; 12-second support body; 13-support seat; 2-telescopic member; 3-middle support plate; 31-connecting arm; 41-first limit member; 42-second limit member; 5-protective film; 6-upper pressure plate; 7-battery cell; 71-large surface of battery cell; 72-corner. DETAILED DESCRIPTION
[0029] The preferred embodiments of the present application are described below with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are merely intended to illustrate the technical principles of the present application and are not intended to limit the scope of protection of the present application. Those skilled in the art may adjust these embodiments as needed to suit specific applications.
[0030] It should be noted that, in the description of this application, unless otherwise clearly specified and limited, the terms "connected" and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected, or indirectly connected through an intermediate medium. For those skilled in the art, the specific meanings of the above terms in this application can be understood according to the specific circumstances. In addition, the terms "upper" and "lower" and other terms indicating directions or positional relationships are based on the directions or positional relationships shown in the drawings. This is only for the convenience of description, and does not indicate or imply that the device or element must have a specific orientation or be constructed in a specific orientation. Therefore, it should not be understood as a limitation on this application.
[0031] The applicant has found through research that when the width of the battery cell reaches a certain level (for example, more than 220mm, which is also related to the electrode material), the stress inside the battery cell cannot support the gravity of the battery cell itself, and the corners 72 on both sides will tend to open like a spring, while the middle part of the battery cell will tend to collapse due to gravity, so the battery cell collapses in the middle and is slightly arched on both sides. In addition, since the tension is basically reduced to 0 after the electrode is cut off during the winding process, the positive and negative electrodes are wound loosely in the last circle, and the negative electrode on the upper surface of the outermost circle has a greater probability of not being able to fit tightly against the lower electrode, resulting in gaps. When the core is cold-pressed after being unwound, the traditional processing method is for the upper pressure plate to first contact the higher places on both sides of the battery cell. During the process of slowly pressing down, the gap in the middle cannot reach the corner 72, so vertical wrinkles are formed on the large surface 71 of the battery cell. In addition, when the core is unloaded during the winding process, the core is separated from the winding needle and flattened. At this time, the electrode in the innermost circle is also likely to collapse (especially when the feeding method starts from the upper half of the core, almost every electrode in the innermost circle will collapse). Although the collapse process can occur in both positive and negative electrodes, due to the greater rigidity of the positive electrode, during the pressing process of the cold pressing plate, the positive electrode can be squeezed to the corner 72 with the gap when the upper pressing plate is pressed down, while the negative electrode has a certain probability that the gap caused by the collapse during the pressing process cannot be squeezed to the corner 72, and wrinkles are formed near the corner 72, which is referred to as the negative electrode wrinkle at the innermost corner 72 in this application.
[0032] Therefore, in order to solve the above-mentioned problem of pole piece wrinkles in the winding core. Figures 1 to 3 As shown, the present application provides a support device for a battery cell shaping mechanism, the support device includes a base 1 and a support plate assembly, the support plate assembly includes a telescopic member 2 and an intermediate support plate 3, the top of the base 1 has a first support body 11 and a second support body 12 arranged at intervals, the first support body 11 and the second support body 12 are used to support the two sides of the battery cell (i.e., the two sides of the lower surface of the battery cell); the intermediate support plate 3 is used to support the middle part of the battery cell, and the intermediate support plate 3 can be telescopically arranged up and down between the first support body 11 and the second support body 12 through the telescopic member 2, and has an extended position protruding from the first support body 11 and the second support body 12 in the vertical direction. Among them, the first support body 11 and the second support body 12 can be a square plate structure or a special-shaped plate structure, etc., and the present application does not limit their shapes. Furthermore, it is understood that the top of the base 1 has a first support 11 and a second support 12 arranged at intervals, and the intermediate support plate 3 is telescopically disposed between the first support 11 and the second support 12 via the telescopic member 2, so that the base, the first support 11, and the second support 12 together form a groove, and the intermediate support plate 3 can be located in the groove. Furthermore, the intermediate support plate 3 is telescopically disposed up and down between the first support 11 and the second support 12 via the telescopic member 2, which means that when viewed from above, the intermediate support plate 2 is located between the first support 11 and the second support 12.
[0033] The battery cell shaping mechanism of the present application also includes an upper pressing plate 6, which is arranged relative to the support device and is configured to be able to move closer to and farther from the support device. Among them, the upper pressing plate 6 can be equipped with a driving device (such as a hydraulic cylinder, a pneumatic cylinder or an electric push rod, etc.). The driving device is connected to the upper pressing plate 6 and controls the movement of the upper pressing plate 6 through a control system to achieve its function of moving closer to and farther from the support device. Its specific implementation method can be any existing method or any method that may appear in the future, and will not be described in detail.
[0034] After the core is flattened, the middle of the battery cell is placed on the middle support plate 3 of the support device during the cold pressing process and / or hot pressing process to ensure that the battery cell is in a shape with a bulge in the middle and drooping on both sides. When the upper pressure plate 6 of the battery cell shaping mechanism descends, it will first contact the middle part of the battery cell. Then, during the downward pressing process, the telescopic part 2 contracts, and the middle support plate 3 slowly descends and retracts under pressure. After retraction, the upper pressure plate 6 can be pressed down with normal pressure. Under the action of the first support body 11 and the second support body 12, pressure can also be applied to both sides of the battery cell to perform cold pressing and / or hot pressing on the battery cell as a whole, ensuring that the battery cell is in good shape throughout the entire process. This solution can solve the problem of wrinkles on the surface of the negative pole in the outermost circle and the problem of wrinkles on the negative pole at the innermost corner 72 (sample size exceeds 2000).
[0035] Wherein, the base 1, the first support body 11 and the second support body 12 of the present application can be integrally formed or separately arranged. When separately arranged, the first support body 11 and the second support body 12 can be installed at intervals on the top of the base 1 by means of connection methods such as bolt connection and clamping. In addition, the telescopic member 2 of the present application can be an elastic member, such as a compression spring, a rubber spring, an air bag or elastic silicone, etc. It is understandable that when the telescopic member 2 is an elastic member, the initial position of the intermediate support plate 3 (when the battery cell pressure is not received) is the extended position, and at this time, the elastic member provides supporting force for the intermediate support plate 3. Of course, this is not restrictive, and the telescopic member 2 can also be replaced by a driving mechanism, such as a cylinder or an electric push rod, etc. As long as the telescopic member 2 can make the intermediate support plate 3 extend and retract relative to the first support body 11 and the second support body 12, the adjustment of the specific form of the telescopic member 2 does not deviate from the principle of the present application and is within the scope of protection of the present application.
[0036] Possibly, the base 1 of the present application has support bases 13 on opposite sides, and the intermediate support plate 3 has connecting arms 31 on opposite sides. The connecting arms 31 on both sides are arranged in a one-to-one correspondence with the support bases 13 on both sides, and a telescopic member 2 is provided between the connecting arms 31 and the support bases 13 on each side. For example, when the telescopic member 2 is a cylinder, the cylinder body is fixed on the support base 13, and the piston rod of the cylinder is fixedly connected to the connecting arm 31, so that the intermediate support plate 3 can be smoothly extended and retracted. For another example, when the telescopic member 2 is an elastic member, one end of the elastic member is fixedly connected to the support base 13, and the other end of the elastic member is fixedly connected to the connecting arm 31, so as to ensure the smooth extension and retraction of the intermediate support plate 3. However, this is not restrictive. Alternatively, the elastic member can be arranged between the bottom of the intermediate support plate 3 and the bottom wall of the groove formed by the base 1, the first support body 11 and the second support body 12. These possible adjustments do not deviate from the principles of the present application and are all within the scope of protection of the present application.
[0037] As a possible embodiment, a first limiter 41 is provided on the base 1, and a second limiter 42 is provided on the intermediate support plate 3. The first limiter 41 and the second limiter 42 cooperate to limit the extension height of the intermediate support plate 3. Possibly, the first limiter 41 includes a vertical mounting block and a horizontal limiter block. The vertical mounting block can be installed on the base through a base, and the horizontal limiter block is provided on the top of the vertical mounting block. The second limiter 42 is configured as a limiter block. A mounting plate can be provided at the lower part of the connecting arm 31, and the limiter block is provided on the mounting plate. The limiter block abuts against the horizontal limiter block to form a limit. However, the specific forms of the first limiter 41 and the second limiter 42 described above are not restrictive. As long as they can limit the extension height of the intermediate support plate 3, their specific structures can be adjusted. For example, as an alternative embodiment, a fixing plate with a limiter hole can be provided on the base 1, and a limiter pin that can be inserted into the hole can be provided on the intermediate support plate 3. When the intermediate support plate 3 is extended to a set height, the stop pin abuts against the hole wall, thereby achieving height control. Alternatively, a guide rail with a stop step can be provided on the base 1, and a slider adapted to the guide rail can be provided at the bottom of the intermediate support plate 3. When the intermediate support plate 3 slides along the guide rail to the extended position, the slider contacts and locks with the step. These possible adjustments do not deviate from the principles of this application and are within the scope of protection of this application.
[0038] As a possible embodiment, when the intermediate support plate 3 is in the retracted position, the intermediate support plate 3 is flush with the upper surfaces of the first support body 11 and the second support body 12. It is understood that the flushness described in this application can mean that the upper surfaces of the intermediate support plate 3 and the first support body 11 and the second support body 12 are coplanar, and a fluctuation of 0.1 mm is allowed. This arrangement ensures that the entire support surface is flat and consistent when the intermediate support plate 3 is retracted, providing uniform support for the battery cell shaping process, avoiding unevenness, and preventing local deformation or indentation of the battery cell structure.
[0039] As a possible embodiment, the entire upper surface of the first support body 11, the intermediate support plate 3, and the second support body 12 is covered with a protective film 5. The thickness of the protective film 5 is preferably greater than 0.1 mm. The protective film 5 can be made of PET film (polyester film), PP film (polypropylene film), PVC film (polyvinyl chloride film), or silicone film, etc. In addition, heavy objects can be hung on both sides of the protective film 5 or tightened by springs to achieve the tension of the protective film 5 and enable it to move up and down with the intermediate support plate 3.
[0040] Because the intermediate support plate 3 needs to move up and down, there will be gaps between it and the first support body 11 and the second support body 12. The gaps must generally be less than or equal to 0.1 mm. Therefore, the entire upper surface of the first support body 11, the intermediate support plate 3, and the second support body 12 is covered with a protective film 5 to prevent defects such as indentations or cracks on the lower surface of the battery cell caused by the gaps.
[0041] As a possible embodiment, a heating element is installed in at least one of the first support body 11, the middle support plate 3 and the second support body 12. The heating element can be a heating rod, a heating tube or a heating plate, etc. Taking a specific embodiment as an example, the heating element is a heating tube, and a hole is punched in the middle of at least one of the first support body 11, the middle support plate 3 and the second support body 12, and the heating tube is installed in the hole, and the heating temperature of the heating tube is ensured to be consistent with the heating temperature of the upper pressing plate 6, and the temperature fluctuation is ≤±3°C. This makes it easy to turn on the heating element in the support device during the hot pressing process, and in cooperation with the heating element in the upper pressing plate 6, the battery cells are evenly heated.
[0042] On the other hand, the present application also provides a battery core processing method, which adopts the above-mentioned battery core shaping mechanism, such as Figure 5 As shown, the method includes the following steps:
[0043] Step S100: During the cold pressing and / or hot pressing process, the middle portion of the target battery cell is placed on the middle support plate in the extended position.
[0044] Step S200: After placement, control the upper pressing plate to move toward the supporting device until the middle supporting plate retracts.
[0045] It is understandable that the middle of the target battery cell described in the present application is not necessarily the exact middle position in the strict sense, as long as the target battery cell is placed on the middle tray in the extended position and there is still margin on both sides of the middle tray.
[0046] Specifically, the target battery cell can be unloaded from the winding needle using a blanking clamp and transferred to the supporting device. The middle of the target battery cell is then placed on the middle support plate in the extended position. After the battery cell is placed, it will form a shape with the middle being pushed up and the two sides sagging. The upper pressing plate is then pressed down until it just touches the battery cell. The blanking clamp pulls out the needle so that the blanking clamp is separated from the battery cell. The upper pressing plate then continues to press down. At this time, the raised part in the middle of the battery cell is stressed, and the raised part is supported by a telescopic member. It is only necessary to make the force of the telescopic member slightly greater than the weight of the battery cell itself (for example, the weight of the battery cell is 100N, and the supporting force of the telescopic member is greater than 100N, such as 105N). During the process of the upper pressing plate pressing down (the press using the upper pressing plate is usually more than 11 tons), the force of the telescopic member pushing upward is relatively small (about tens of kilograms), so the raised middle support plate descends with the upper pressing plate until it descends to a position coplanar with the upper surface of the first support and the second support.
[0047] The cold pressing process can perform preliminary shaping of the battery cells, while the hot pressing process can further effectively shape the battery cells. It is understandable that during the hot pressing process, the heating elements in the support device and the upper platen need to be turned on, and after the hot pressing process time is met, the upper platen is lifted. In this case, the middle support plate will also move upward under the drive of the telescopic member to lift the battery cells, which can free up space for the robot arm to avoid the battery cells.
[0048] After a large number of experimental verifications, the above method can reduce the probability of wrinkles on the large surface of the negative electrode in the outermost circle of the large battery cell and the negative electrode wrinkles at the innermost corner to zero.
[0049] As a possible implementation, before step S100, the method of the present application also includes: when the width of the target battery cell is greater than or equal to a preset width, adjusting the width and extension height of the middle tray based on the width and thickness of the target battery cell, so that after the target battery cell is placed on the support device, the middle part of the target battery cell can protrude beyond both sides of the target battery cell.
[0050] Among them, when the battery cell is larger than the preset width, the internal stress cannot support the weight of the battery cell itself, and the battery cell appears to be collapsed in the middle and slightly arched on both sides. For example, when the width of the target battery cell is ≥220mm, the battery cell appears to be collapsed in the middle and slightly arched on both sides, and the preset width is 220mm. At this time, a battery cell shaping mechanism is required to shape the battery cell. Of course, the above-mentioned preset width of 220mm is only a possible embodiment, which can be adjusted according to actual application. For example, when the battery cell is greater than or equal to 180mm, it appears to be collapsed in the middle and slightly arched on both sides. The preset width can be adjusted to 180mm. These possible value changes do not deviate from the principles of this application and are all within the scope of protection of this application.
[0051] According to a large number of verifications, the width and protruding height of the middle tray of the support device can be calculated from the width and thickness of the target battery cell, so that after the target battery cell is placed on the support device, the middle part of the target battery cell can protrude from both sides of the target battery cell. Among them, after determining the width of the middle tray, the middle tray can be redesigned; in addition, after determining the protruding height of the middle tray, the protruding height can be adjusted by the design of the telescopic member or the limiting cooperation of the first limit member and the second limit member. In addition, there are many specific implementation methods for calculating the width and protruding height of the middle tray of the support device based on the width and thickness of the target battery cell. For example, if the width of the target battery cell is m1 and the thickness is n, the calculation formula for the width m2 of the middle tray is: m2=1 / 2(m-2n). The value range of the protruding height h of the middle tray is: 1 / 3n<h<1 / 2n. For another example, a comparison table of the width and thickness of the target battery cell and the width and protruding height of the intermediate support plate is obtained through experimental summary, and the width and protruding height of the intermediate support plate can be determined based on the comparison table. It is understood that the protruding height of the intermediate support plate in this application refers to the height of the intermediate support plate protruding relative to the upper surface defined by the first support body and the second support body.
[0052] On the other hand, after the battery cell is baked, injected with liquid, and fully charged and then disassembled, large areas of negative electrode wrinkles will appear. The main reason is that the spacing between the electrodes of the winding core is not large enough. During the charging process, the thickness of the electrode increases and causes pulling, which squeezes and deforms the softer negative electrode, forming wrinkles.
[0053] In order to improve the wrinkling of the negative electrode after full charge, the method of the present application also includes: in the winding process, adjusting the pressure of the embossing roller to a pressure that makes the spacing between the pole pieces of the core equal to the preset gap, so as to emboss the pole pieces; wherein the preset gap is determined based on the thickness difference between the positive pole piece before and after winding, the thickness difference between the negative pole piece before and after winding, and the spacing between the pole pieces of the original core. The preset gap is: original GAP (the spacing between the pole pieces of the original core) + increased GAP (the spacing between the pole pieces of the core that needs to be increased), wherein the calculation formula of increased GAP can be: increased GAP = 1.5 (Δ positive + Δ negative - original GAP), Δ positive is the thickness difference between the positive pole piece before and after winding, and Δ negative is the thickness difference between the negative pole piece before and after winding.
[0054] It is understood that the spacing between the original core pole pieces refers to the spacing between the core pole pieces under the original process, such as the spacing between the core pole pieces before the embossing process; or the spacing between the core pole pieces after the embossing process but not made using the method of the present application. Among them, the spacing between the core pole pieces of the present application can be the distance between the negative pole pieces, or the distance between the positive pole pieces. In addition, it is understood that embossing refers to applying pressure on the surface of the pole piece by an embossing roller to form a uniform concave-convex structure, a mesh or honeycomb structure, a trapezoidal or serrated structure, etc.
[0055] There are several methods for determining the spacing between the pole pieces of the core produced by this method and / or the spacing between the pole pieces of the original core:
[0056] For example, the first circumference of the outermost circle of the wound cell and the second circumference of the winding needle are measured. The first radius is obtained based on the first circumference, and the second radius is obtained based on the second circumference. The difference between the first and second radii is the radius difference. The radius difference minus the thickness of all pole pieces and diaphragms can be used to obtain the spacing between the pole pieces of the core. However, this method has too large an error. The scheme of measuring the circumference of the tail coil has a large human factor. It is normal for the measurement result to fluctuate by ±1mm, but even a fluctuation of ±1mm can cause a very large error (the spacing between the pole pieces of the core is originally measured at the μm level).
[0057] To this end, this method uses the amount of tab misalignment to determine the spacing between the winding core pole pieces, which is more accurate. It is understood that the tabs of the winding core should be aligned, and tab misalignment is the distance that the tabs are offset from the alignment. For example, the distance between the center lines of the tabs is the misalignment.
[0058] The applicant has discovered through research that the spacing between the pole pieces in the core is directly proportional to the amount of tab misalignment. For a core with 51 turns, a 1μm change in the spacing between the pole pieces will result in an 8.33mm tab misalignment. Therefore, the spacing between the pole pieces in the core can be calculated based on this relationship: tab misalignment × 1μm / 8.33mm. Of course, the above values will vary for cores with different numbers of turns, and the values can be obtained based on actual conditions.
[0059] It should be noted that the specific implementation method for determining the spacing between the core pole pieces by the misalignment of the tabs is not limited to the above one. For example, a comparison table comparing the misalignment of the tabs and the spacing between the core pole pieces can be summarized through experiments. After measuring the misalignment of the tabs, the spacing between the core pole pieces can be obtained by looking up the table. These possible adjustments do not deviate from the principles of this application and are all within the scope of protection of this application.
[0060] After extensive verification, the above method can solve the problem of electrode wrinkling after full charge. Generally speaking, the spacing between the core electrodes of 6μm is more effective for full charge disassembly.
[0061] As a possible implementation, the method of this application also includes: During the formation process, a clamp is used to apply pressure to both sides of the target cell, thereby limiting the expansion of the cell's large surface area. After disassembly, it was found that the addition of a restraining clamp during the formation process can significantly improve the problem of electrode wrinkling after full charging.
[0062] The present application adopts the above-mentioned battery cell shaping mechanism and method, which can achieve the following beneficial effects:
[0063] 1. Improve product quality. Before and after the implementation of the solution described in this application, the wrinkle ratio of the negative electrode on the outermost ring of the winding core was statistically analyzed and found to be significantly improved. Before this solution was adopted, the average wrinkle ratio exceeded 50%, while with this solution, the wrinkle ratio was 0%;
[0064] 2. High feasibility for mass production. The solution described in this application does not significantly increase the difficulty or cost of building a new production line, but brings very substantial benefits. The cost of renovating existing production lines is also low. This solution is suitable for large-scale production line application.
[0065] 3. Easy operation: Whether it is equipment modification or new equipment development, the solution described in this application is very convenient and simple.
[0066] 4. Applicable to a wide range of products. According to the method described in this application, the corresponding mechanism size can be designed according to the width of the large battery cell, ensuring the good shape of the battery cell during cold pressing, hot pressing, and mechanism operation, ensuring the hot pressing effect, and improving the wrinkling problem of the outermost negative electrode.
[0067] A possible implementation of the battery cell processing method of the present application is introduced below. Figure 6 As shown, the following steps are included:
[0068] Step S301: During the winding process, the pressure of the embossing roller is adjusted to a pressure that makes the spacing between the pole pieces of the winding core equal to a preset gap, so as to emboss the pole pieces.
[0069] Step S302 : When the width of the target battery cell is greater than or equal to the preset width, the width and the extension height of the intermediate support plate are adjusted based on the width and thickness of the target battery cell.
[0070] Step S303: placing the middle portion of the target battery cell on the middle support plate in the extended position.
[0071] Step S304: After placement, control the upper pressing plate to move toward the supporting device until the middle supporting plate retracts.
[0072] Step S305: During the formation process, a clamp is used to apply pressure to both sides of the target battery cell.
[0073] It should be noted that the above-mentioned implementation mode is only used to illustrate the principles of the present application and is not intended to limit the scope of protection of the present application. Without departing from the principles of the present application, those skilled in the art can adjust the above-mentioned structure so that the present application can be applied to more specific application scenarios.
[0074] For example, the present application can omit the provision of the first limiting member 41 and the second limiting member 42 , and the extension height of the middle support plate 3 can also be limited through the design of the telescopic member 2 .
[0075] For example, the protective film 5 may be omitted, and / or no heating element may be installed in the first support body 11 , the intermediate support plate 3 and the second support body 12 .
[0076] Thus far, the technical solutions of the present application have been described in conjunction with the preferred embodiments shown in the accompanying drawings. However, it is readily understood by those skilled in the art that the scope of protection of the present application is obviously not limited to these specific embodiments. Without departing from the principles of the present application, those skilled in the art may make equivalent changes or substitutions to the relevant technical features, and the technical solutions after such changes or substitutions will fall within the scope of protection of the present application.
Claims
1. A supporting device for a battery cell shaping mechanism, characterized in that: include: A base (1) having a first support body (11) and a second support body (12) arranged at intervals on the top, wherein the first support body (11) and the second support body (12) are used to support two sides of the battery core; A support plate assembly comprises a telescopic member (2) and an intermediate support plate (3), wherein the intermediate support plate (3) is used to support the middle portion of the battery cell, and the intermediate support plate (3) is arranged between the first support body (11) and the second support body (12) in a telescopic manner via the telescopic member (2), and has an extended position protruding from the first support body (11) and the second support body (12) in the vertical direction.
2. The supporting device of the battery cell shaping mechanism according to claim 1, characterized in that: When the intermediate support plate (3) is in the retracted position, it is flush with the upper surfaces of the first support body (11) and the second support body (12).
3. The supporting device of the battery cell shaping mechanism according to claim 1 or 2, characterized in that: The entire upper surfaces of the first support body (11), the intermediate support plate (3) and the second support body (12) are covered with a protective film (5).
4. The supporting device of the battery cell shaping mechanism according to claim 1, characterized in that: The telescopic member (2) is configured as an elastic member or a driving mechanism; and / or The base (1) has support seats (13) on two opposite sides, and the intermediate support plate (3) has connecting arms (31) on two opposite sides, the connecting arms (31) on both sides are arranged in a one-to-one correspondence with the support seats (13) on both sides, and the telescopic member (2) is provided between the connecting arm (31) and the support seat (13) on each side; and / or A first limiting member (41) is provided on the base (1), and a second limiting member (42) is provided on the intermediate support plate (3). The first limiting member (41) and the second limiting member (42) cooperate to limit the extension height of the intermediate support plate (3).
5. The supporting device of the battery cell shaping mechanism according to claim 1, characterized in that: A heating element is installed in at least one of the first support body (11), the intermediate support plate (3) and the second support body (12).
6. A battery cell shaping mechanism, characterized in that: The supporting device comprises the supporting device according to any one of claims 1 to 5, and further comprises an upper pressing plate (6), wherein the upper pressing plate (6) is arranged opposite to the supporting device and is arranged to be able to approach and move away from the supporting device.
7. A method for processing a battery core, characterized in that: The method adopts the battery cell shaping mechanism according to claim 6, and the method comprises: During the cold pressing and / or hot pressing process, placing the middle portion of the target battery cell on the middle support plate in the extended position; After placement, the upper pressing plate is controlled to move toward the supporting device until the middle supporting plate is retracted.
8. The battery core processing method according to claim 7, characterized in that: Before the step of “placing the middle portion of the target battery cell on the intermediate support plate in the extended position”, the method further includes: When the width of the target battery cell is greater than or equal to the preset width, the width and extension height of the intermediate support plate are adjusted based on the width and thickness of the target battery cell so that after the target battery cell is placed on the supporting device, the middle part of the target battery cell can protrude from both sides of the target battery cell.
9. The battery core processing method according to claim 7, characterized in that: The method further comprises: During the winding process, the pressure of the embossing roller is adjusted to a pressure that makes the spacing between the pole pieces of the winding core equal to the preset gap, so as to emboss the pole pieces; The preset gap is determined based on the thickness difference of the positive electrode sheet before and after winding, the thickness difference of the negative electrode sheet before and after winding, and the spacing between the electrode sheets of the original winding core.
10. The battery core processing method according to claim 9, characterized in that: The method further comprises: During the formation process, a fixture is used to apply pressure to both sides of the target cell; and / or The spacing between the pole pieces of the winding core of the present method and / or the spacing between the pole pieces of the original winding core are obtained based on the misalignment of the pole tabs.