A flattening device for wound bare cells
Patent Information
- Application Number
- CN202522205841.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-10-17
- Publication Date
- 2026-10-23
- Estimated Expiration
- 2035-10-17
AI Technical Summary
[0003]本实用新型提供一种卷绕式裸电芯的压平装置，以解决卷绕式裸电芯在经过压平工序后容易产生褶皱的技术问题
[0014]本实用新型的有益效果：本实用新型提出的一种卷绕式裸电芯的压平装置，通过上压板上设置两个沿第一方向间距设置的接触部，在对卷绕裸电芯进行压平的过程中，由于接触部凸出于工作面，因此相较于工作面，接触部先与卷绕裸电芯上侧部分的极片接触。卷绕裸电芯上侧的极片与接触部接触后，在接触部的引导下，能够沿卷绕裸电芯的宽度方向，分别向卷绕裸电芯的两端延展滑动，以避免卷绕裸电芯上侧部分的极片产生褶皱，从而提升卷绕式裸电芯的良品率，并增加锂离子电池的安全性能。
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Figure CN224889652U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of battery cell processing equipment technology, and in particular to a flattening device for a wound bare battery cell. Background Technology
[0002] Lithium-ion batteries typically consist of a casing and bare cells housed within it. For wound bare cells, they usually need to be flattened after winding to ensure a tight fit between the electrodes and the separator, and to conform to the casing dimensions. During the flattening process of wound bare cells, the electrodes on the upper side of the cell are prone to collapsing under their own weight, resulting in redundancy. After the flattening process, this redundancy can easily cause wrinkles on the upper part of the bare cell, thereby reducing the yield rate and affecting the safety of the lithium-ion battery. Utility Model Content
[0003] This utility model provides a flattening device for wound bare battery cells to solve the technical problem that wound bare battery cells are prone to wrinkles after the flattening process.
[0004] This utility model provides a flattening device for a wound bare battery cell, including an upper pressure plate and a lower pressure plate arranged opposite to each other. The lower surface of the upper pressure plate has a working surface for contacting the wound bare battery cell. The upper pressure plate has a first direction that is in the same direction as the width direction of the wound bare battery cell during the flattening process. The working surface is provided with two contact portions arranged at intervals along the first direction, and both contact portions protrude from the working surface.
[0005] In one embodiment of the present invention, the contact portion has a smooth surface for contacting the wound bare battery cell, and the coefficient of friction of the smooth surface is less than the coefficient of friction of the working surface.
[0006] In one embodiment of this utility model, the contact portion is block-shaped and is attached to the lower surface of the upper pressure plate.
[0007] In one embodiment of the present invention, the contact portion is a plating or coating layer attached to the lower surface of the upper pressure plate.
[0008] In one embodiment of this utility model, the contact portion is an elastomer.
[0009] In one embodiment of this utility model, a groove is provided on the lower surface of the upper pressure plate, the groove is correspondingly provided with the contact portion, the contact portion is installed in the groove, and when the wound bare battery cell is pressed into place, the surface of the contact portion facing the lower pressure plate is flush with the working surface.
[0010] In one embodiment of this utility model, the height of the contact portion protruding from the working surface is 0.05mm to 2.00mm.
[0011] In one embodiment of this utility model, the working surface of the upper pressure plate is a frosted surface.
[0012] In one embodiment of this utility model, both the upper pressure plate and the lower pressure plate are provided with heating components.
[0013] In one embodiment of the present invention, the upper pressure plate has a mounting surface facing away from the lower pressure plate, the heating assembly includes a heating pipe, the heating assembly is disposed on the mounting surface, and the heating pipe is in contact with the mounting surface; Alternatively, the heating assembly may include heating channels disposed within the upper pressure plate and the lower pressure plate.
[0014] The beneficial effects of this utility model are as follows: This utility model proposes a flattening device for wound bare battery cells. Two contact portions spaced apart along a first direction are provided on the upper pressure plate. During the flattening process of the wound bare battery cell, because the contact portions protrude from the working surface, they first contact the electrode sheets on the upper side of the wound bare battery cell compared to the working surface. After the electrode sheets on the upper side of the wound bare battery cell contact the contact portions, they can slide along the width direction of the wound bare battery cell towards both ends under the guidance of the contact portions. This prevents wrinkles from forming on the electrode sheets on the upper side of the wound bare battery cell, thereby improving the yield of wound bare battery cells and increasing the safety performance of lithium-ion batteries. Attached Figure Description
[0015] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application. It is obvious that the drawings described below are merely some embodiments of this application, and those skilled in the art can obtain other drawings based on these drawings without any inventive effort.
[0016] In the attached diagram: Figure 1 A schematic diagram of the structure of a flattening device for a wound bare battery cell provided in an embodiment of this utility model; Figure 2 A second schematic diagram of the structure of the flattening device for a wound bare battery cell provided in an embodiment of this utility model; Figure 3 This is a schematic diagram of a wound bare battery cell being flattened into a shaped bare battery cell according to an embodiment of the present invention; Figure 4 for Figure 2 A magnified schematic diagram of the middle contact area.
[0017] The attached figures are labeled as follows: 1. Upper pressure plate, 2. Contact part, 3. Winded bare cell, 4. Lower pressure plate, 5. Molded bare cell, 6. First direction K, 7. Lowering direction H. Detailed Implementation
[0018] The following specific examples illustrate the implementation of this utility model. Those skilled in the art can easily understand other advantages and effects of this utility model from the content disclosed in this specification. This utility model can also be implemented or applied through other different specific embodiments. Various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of this utility model. In the absence of conflict, the following embodiments and features in the embodiments can be combined with each other.
[0019] It should be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of the present invention. The drawings only show the components related to the present invention and are not drawn according to the actual number, shape and size of the components. In actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.
[0020] In the following description, numerous details are explored to provide a more thorough explanation of embodiments of the present invention. However, it will be apparent to those skilled in the art that embodiments of the present invention may be practiced without these specific details. In other embodiments, well-known structures and devices are shown in block diagram form rather than in detail to avoid obscuring embodiments of the present invention.
[0021] In the production process of wound bare cells, the electrode sheets and separators are first wound around the center to form a wound bare cell 3. The wound bare cell 3 is the process state of the wound bare cell. After the flattening step, the wound bare cell 3 becomes a flat shaped bare cell 5. The width direction of the shaped bare cell 5 is also the width direction of the wound bare cell 3, and the thickness direction of the shaped bare cell 5 is the thickness direction of the wound bare cell 3, which is parallel to the pressing direction H of the flattening device. Therefore, the width direction of the wound bare cell 3 is perpendicular to the thickness direction of the wound bare cell 3 and the winding axis direction of the wound bare cell 3.
[0022] During the flattening process of the bare cell 3, the electrode sheets located above the winding center of the bare cell 3 are prone to collapse under their own weight, resulting in redundancy. This redundancy causes the electrode sheets located above the winding center of the bare cell 3 to easily develop wrinkles after the flattening process, which in turn leads to a decrease in the yield of the bare cell and affects the safety of the lithium-ion battery.
[0023] Meanwhile, increasing the size of the bare cell is beneficial for improving the energy density and power density of the battery and reducing the manufacturing cost. Therefore, the size of the wound bare cell tends to be larger, resulting in a further increase in the size of the wound bare cell 3. The increased size of the wound bare cell 3 further increases the risk that the electrode sheet located on the upper part of the winding center of the wound bare cell 3 will collapse before being flattened.
[0024] In view of this, please see Figure 1 This embodiment provides a flattening device for a wound bare battery cell, including an upper pressure plate 1 and a lower pressure plate 4 arranged opposite to each other. The lower surface of the upper pressure plate 1 has a working surface for contacting the wound bare battery cell 3. The upper pressure plate 1 has a first direction that is in the same direction as the width direction of the wound bare battery cell 3 during the flattening process. The working surface is provided with two contact portions 2 arranged at a distance K along the first direction. Both contact portions 2 protrude from the working surface.
[0025] By providing two contact portions 2 spaced along the first direction K on the upper pressure plate 1, during the process of flattening the wound bare cell 3, the electrode sheet on the upper side of the wound bare cell 3 can slide and extend towards both ends of the wound bare cell 3 along the width direction of the wound bare cell 3 under the guidance of the contact portions, so as to avoid wrinkles on the electrode sheet on the upper side of the wound bare cell 3, thereby improving the yield of the wound bare cell and the safety performance of the lithium-ion battery.
[0026] Specifically, in this embodiment, during the actual production process of the wound bare battery cell, when pre-pressing or cold-pressing the wound bare battery cell, the wound bare battery cell 3 is first placed between the upper pressure plate 1 and the lower pressure plate 4 of the flattening device, with the width direction of the wound bare battery cell 3 parallel to the first direction K of the upper pressure plate 1, and the thickness direction of the wound bare battery cell 3 parallel to the downward pressing direction H of the upper pressure plate 1. The wound bare battery cell 3 has two pressure-receiving areas corresponding to the two contact portions 2, respectively. The two pressure-receiving areas are respectively close to both ends of the wound bare battery cell 3 along the width direction. During the flattening process of the wound bare battery cell 3, the two pressure-receiving areas contact the two contact portions 2.
[0027] After the wound bare cell 3 is placed on the lower pressure plate 4, the middle part of the electrode sheet above the winding center of the wound bare cell 3 collapses under its own weight. Therefore, the two ends on the upper side of the wound bare cell 3, which are opposite each other in the width direction of the wound bare cell 3, will form upward bulges. The upward bulges are located in the pressure zone. During the flattening process of the wound bare cell, the upper pressure plate 1 is pressed down (that is, pressed down on the lower pressure plate 4). The upward bulges of the wound bare cell 3 first contact the contact part 2 of the upper pressure plate 1. After the upward bulges at both ends of the wound bare cell 3 contact the contact part 2, as the upper pressure plate 1 continues to press down, the upward bulges at both ends of the wound bare cell 3 will slide and extend to both ends in the width direction of the wound bare cell 3 under the action of the contact part 2 until the working surface of the upper pressure plate 1 contacts the rest of the surface on the upper side of the wound bare cell 3. Since the portion of the wound bare cell 3 that first contacts the upper pressure plate 1 can slide to both ends along the width direction of the wound bare cell 3 (that is, parallel to the first direction K), the redundancy caused by the collapse of the middle of the wound bare cell 3 due to its own weight can be eliminated. This helps to avoid wrinkles on the side of the wound bare cell 3 facing the upper pressure plate 1 after being flattened, thereby improving the yield of the wound bare cell and the safety performance of the lithium-ion battery.
[0028] In one embodiment of this utility model, the contact portion 2 has a smooth surface for contacting the pressure area on the wound bare cell 3, and the friction coefficient of the smooth surface is less than that of the working surface. In this embodiment, the lower surface of the contact portion 2 contacts the wound bare cell 3 during the flattening process, that is, the lower surface of the contact portion 2 is a smooth surface. When the wound bare cell 3 contacts the smooth surface, the part of the wound bare cell 3 that contacts the smooth surface of the contact portion 2 (i.e., the pressure area) can easily slip relative to the smooth surface. Thus, during the pressing process of the upper pressure plate 1 of the flattening device, the electrode sheet on the upper side of the wound bare cell 3 (i.e., the part of the wound bare cell 3 facing the upper pressure plate) slides and extends to both ends along its width direction, thereby avoiding redundancy in the part of the wound bare cell 3 facing the upper pressure plate 1.
[0029] In this embodiment, the working surface of the upper pressure plate 1 is a frosted surface. The frosted surface has a high coefficient of friction. After the working surface comes into contact with the wound bare cell 3, it can limit the electrode sheets on the wound bare cell 3 that are in contact with the working surface during the flattening process. After the wound bare cell 3 comes into contact with the working surface, it helps to avoid relative slippage between the electrode sheets of each layer of the wound bare cell 3 during the flattening process, thereby improving the flattening effect.
[0030] In one embodiment of this utility model, the contact part 2 is block-shaped and is pasted on the lower surface of the upper pressure plate 1. The contact part 2 is installed on the upper pressure plate 1 by pasting, which is relatively convenient for assembly. For example, the contact part 2 can be formed by pasting a Teflon block on the lower surface of the upper pressure plate 1.
[0031] In some other embodiments of this utility model, the contact portion 2 can also be a plating or coating attached to the lower surface of the upper pressure plate 1. The plating or coating has advantages such as reliable connection and less material usage. Specifically, the coating material can be Teflon, molybdenum disulfide coating, tungsten disulfide coating, or diamond-like carbon coating, etc., and the plating can be an electroless nickel-polytetrafluoroethylene composite plating or a hard chrome plating, etc.
[0032] like Figures 2 to 4 As shown, in some embodiments of this utility model, the contact portion 2 can be an elastic body. During the process of the upper pressure plate 1 flattening the wound bare cell 3, the two contact portions 2 can be offset towards both ends of the wound bare cell 3 along the width direction of the wound bare cell 3 (that is, parallel to the first direction K), so that the part of the wound bare cell 3 that contacts the contact portion 2 can slide and translate towards both ends of the wound bare cell 3 along the width direction of the wound bare cell 3, which helps to eliminate the redundancy of the electrode sheet on the upper part of the wound bare cell 3.
[0033] In this embodiment, a groove is provided on the lower surface of the upper pressure plate 1, and the groove corresponds to the contact part 2. The contact part 2 is installed in the groove and protrudes from the lower surface of the upper pressure plate 1. When the bare battery cell 3 is wound and pressed into place, the surface of the contact part 2 facing the lower pressure plate 4 is flush with the working surface of the upper pressure plate 1. By providing the groove, the compressed contact part 2 can be accommodated, so that the surface of the contact part 2 facing the lower pressure plate 4 can be flush with the working surface of the upper pressure plate 1. This makes the upper surface of the molded bare battery cell 5 formed after the bare battery cell 3 is wound and pressed more flat, which helps to reduce the internal stress of the bare battery cell and improve the yield of the bare battery cell.
[0034] In one embodiment, the height of the contact portion 2 protruding from the working surface is 0.05mm to 2mm. Since the contact portion 2 is compressed and deformed during the flattening process, a height greater than or equal to 0.05mm allows sufficient time for the portion of the wound bare cell 3 in contact with the contact portion 2 to slide and shift during flattening, ensuring that redundancy is eliminated effectively. A height less than or equal to 2mm prevents indentations from forming on the upper surface of the molded bare cell 5 due to excessive protrusion, thus ensuring the factory quality of the bare cell.
[0035] In one embodiment of this invention, along the direction perpendicular to the working surface, i.e., along the downward pressing direction H of the upper pressure plate 1, the projection of the contact portion 2 can cover the arc-shaped corner area of the wound bare battery cell 3. During the process of the upper pressure plate 1 flattening the wound bare battery cell 3, the dimension of the wound bare battery cell 3 in its width will increase. The contact portion 2 along the downward pressing direction H of the upper pressure plate 1 at least covers the arc-shaped corner area of the wound bare battery cell 3. This helps to prevent the wound bare battery cell 3 from contacting the working surface of the upper pressure plate 1 prematurely after the width of the wound bare battery cell 3 increases, thereby ensuring that the part of the wound bare battery cell 3 in contact with the contact portion 2 can slide and shift sufficiently to eliminate redundancy on the upper surface of the wound bare battery cell 3.
[0036] Specifically, such as Figure 1 and Figure 3 As shown, in one embodiment of the present invention, the wound bare battery cell 3 is hot-pressed to form a shaped bare battery cell 5. The thickness of the shaped bare battery cell 5 is T, the dimension of the shaped bare battery cell 5 in the width direction is W, the maximum distance between the two contact parts 2 in the width direction of the wound bare battery cell 3 is D, and the minimum distance between the two contact parts 2 in the width direction of the wound bare battery cell 3 is d.
[0037] Where D≥WT and WTd≥20mm, along the downward pressing direction H of the upper pressure plate 1, the contact part 2 has a sufficient projected area to prevent the width of the wound bare cell 3 from increasing prematurely and contacting the working surface of the upper pressure plate 1 during the flattening process, thus ensuring the sliding offset effect of the part of the wound bare cell 3 in contact with the contact part 2.
[0038] In this embodiment, both the upper pressure plate 1 and the lower pressure plate 4 are hot-pressing plates, meaning that both the upper pressure plate 1 and the lower pressure plate 4 are equipped with heating components. These heating components can heat the wound bare battery cell during the flattening process. By using a hot-pressing process during flattening, the forming effect of the wound bare battery cell can be improved, which helps to avoid the springback of the wound bare battery cell after flattening.
[0039] Specifically, in this embodiment, the upper pressure plate 1 has a mounting surface facing away from the lower pressure plate 4. The heating assembly includes a heating pipe, which is disposed on the mounting surface and in contact with the mounting surface to heat the upper pressure plate 1 and the lower pressure plate 4, thereby enabling hot pressing processing of the wound bare battery cell 3. In some embodiments, the lower pressure plate 4 also has a mounting surface facing away from the upper pressure plate 1 and is also provided with a heating assembly to heat the lower pressure plate 4.
[0040] Since the heating component is set independently relative to the upper pressure plate 1 and the lower pressure plate 4, the upper pressure plate 1, the lower pressure plate 4 and the heating component can be processed separately and then assembled, so as to reduce the overall processing difficulty of the flattening device, and also facilitate the maintenance and replacement of the heating component, thereby reducing the maintenance cost of the flattening device.
[0041] In another embodiment of the present invention, the heating component includes a heating channel, which is disposed inside the upper pressure plate 1 and the lower pressure plate 4. The heating channel is disposed inside the upper pressure plate 1 and the lower pressure plate 4, which has the advantages of high heat exchange efficiency and good heating effect.
[0042] In summary, by providing two contact portions 2 spaced along the first direction K on the upper pressure plate 1, during the flattening process of the wound bare cell 3, the electrode sheets on the upper side of the wound bare cell 3 can extend and slide towards both ends of the wound bare cell 3 along the width direction of the wound bare cell 3 under the guidance of the contact portions 2, so as to avoid wrinkles on the electrode sheets on the upper side of the wound bare cell 3, thereby improving the yield of the wound bare cell and increasing the safety performance of the lithium-ion battery.
[0043] The above embodiments are merely illustrative of the principles and effects of this utility model and are not intended to limit the scope of this utility model. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of this utility model. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in this utility model should still be covered by the claims of this utility model.
Claims
1. A flattening device for a wound bare battery cell, characterized in that, It includes an upper pressure plate and a lower pressure plate arranged opposite to each other. The lower surface of the upper pressure plate has a working surface for contacting the wound bare battery cell. The upper pressure plate has a first direction that is in the same direction as the width direction of the wound bare battery cell during the flattening process. The working surface is provided with two contact portions arranged at a distance along the first direction. Both contact portions protrude from the working surface.
2. The flattening device for wound bare cells according to claim 1, characterized in that: The contact portion has a smooth surface for contacting the wound bare battery cell, and the coefficient of friction of the smooth surface is less than the coefficient of friction of the working surface.
3. The flattening device for wound bare cells according to claim 2, characterized in that: The contact part is block-shaped and is attached to the lower surface of the upper pressure plate.
4. The flattening device for wound bare cells according to claim 2, characterized in that: The contact portion is a plating or coating attached to the lower surface of the upper pressure plate.
5. The flattening device for wound bare cells according to claim 1, characterized in that: The contact portion is an elastomer.
6. The flattening device for wound bare cells according to claim 5, characterized in that: The lower surface of the upper pressure plate is provided with a groove, which is correspondingly provided with the contact part. The contact part is installed in the groove. When the wound bare battery cell is pressed into place, the surface of the contact part facing the lower pressure plate is flush with the working surface.
7. The flattening device for wound bare cells according to any one of claims 1-6, characterized in that: The height of the contact portion protruding from the working surface is 0.05mm to 2.00mm.
8. The flattening device for wound bare cells according to any one of claims 1-6, characterized in that: The working surface of the upper pressure plate is a frosted surface.
9. The flattening device for wound bare cells according to any one of claims 1-6, characterized in that: Both the upper pressure plate and the lower pressure plate are equipped with heating components.
10. The flattening device for wound bare cells according to claim 9, characterized in that: The upper pressure plate has a mounting surface facing away from the lower pressure plate, and the heating assembly includes a heating pipe. The heating assembly is disposed on the mounting surface, and the heating pipe is in contact with the mounting surface. Alternatively, the heating assembly may include heating channels disposed within the upper pressure plate and the lower pressure plate.