Winding type battery cell, method of manufacturing the same, and battery device

Abstract

The present disclosure relates to the technical field of batteries, and discloses a wound cell, a preparation method thereof, and a battery device. The preparation method of the wound cell comprises the following steps: providing a to-be-wound film layer group and a plurality of insulating plates, wherein the to-be-wound film layer group comprises a first separator, a first pole piece, a second separator, and a second pole piece which are sequentially stacked; winding the to-be-wound film layer group and the plurality of insulating plates to form a wound structure, wherein the wound structure has a flat plate part and an arc part, and the insulating plates are at least partially located in the arc part; and extracting the insulating plates. The preparation method of the wound cell does not cause stress concentration of the first pole piece and the second pole piece, thereby reducing the expansion stress of the arc part, avoiding problems such as purple spots and lithium precipitation in the position of the arc part, and improving the cycle life of the wound cell, thereby improving the service life of the battery device. Moreover, the wound cell is beneficial to be installed into a battery shell, and is beneficial to improve the energy density of the battery device.

Description

Technical Field

[0001] This disclosure relates to the field of battery technology, and more specifically, to a wound battery cell, its preparation method, and a battery device. Background Technology

[0002] Wound battery cells are widely used due to their high production efficiency; however, during charging and discharging, lithium ions migrate between the positive and negative electrodes, and the thickness of the positive and negative electrodes changes as lithium ions are inserted and extracted. At the corners (arc sections) of wound battery cells, the gap between the positive and negative electrodes is smaller. When the thickness of the positive and negative electrodes changes, they are easily squeezed, leading to stress concentration at the corners. This causes problems such as purple spots and lithium plating to easily occur at the arc sections, resulting in faster battery performance degradation.

[0003] It should be noted that the information disclosed in the background section above is only used to enhance the understanding of the background of this disclosure, and therefore may include information that does not constitute prior art known to those skilled in the art. Summary of the Invention

[0004] The purpose of this disclosure is to overcome the shortcomings of the above-mentioned related technologies and to provide a wound battery cell, its preparation method, and battery device.

[0005] According to one aspect of this disclosure, a method for manufacturing a wound battery cell is provided, comprising: A film layer assembly to be wound and multiple insulating plates are provided. The film layer assembly to be wound includes a first diaphragm, a first electrode, a second diaphragm, and a second electrode arranged in sequence. The film layer assembly to be wound and the plurality of insulating plates are wound to form a winding structure, the winding structure having a flat portion and an arc-shaped portion, and the insulating plates are at least partially located in the arc-shaped portion; Remove the insulating plate.

[0006] The disclosed method for manufacturing a wound battery cell, on the one hand, involves an insulating plate at least partially located in the arc-shaped portion. The structure of this arc-shaped portion can be controlled via the insulating plate; for example, it can ensure the space between the first and second electrodes. Furthermore, different sizes of insulating plates can be designed and selected according to the expansion degree of the wound battery cell, thereby ensuring different space sizes between the first and second electrodes, reducing expansion stress in the arc-shaped portion, avoiding problems such as purple spots and lithium plating at the arc-shaped portion, and improving the cycle life of the wound battery cell. On the other hand, removing the insulating plate to form the wound battery cell prevents the insulating plate from affecting the transport of lithium ions between the first and second electrodes, ensuring the electrical performance of the wound battery cell; it also reduces the weight of the wound battery cell and increases its energy density.

[0007] According to another aspect of this disclosure, a wound battery cell is provided, comprising: The first diaphragm, the first electrode, the second diaphragm, and the second electrode are stacked and wound together in sequence, and include a flat plate portion and an arc-shaped portion connected to each other. In the arc-shaped portion, the distance between adjacent first electrode and second electrode is greater than or equal to 15 micrometers and less than or equal to 50 micrometers.

[0008] The wound cell disclosed herein provides a suitable space between the first and second electrodes, preventing stress concentration between them and reducing expansion stress in the arc-shaped portion. This avoids problems such as purple spots and lithium plating in the arc-shaped portion, thus improving the cycle life of the wound cell. Furthermore, it facilitates the installation of the wound cell into the battery casing.

[0009] According to another aspect of this disclosure, a battery device is provided, comprising: the wound battery cell described above.

[0010] The battery device disclosed herein provides a suitable space between the first and second electrodes, preventing stress concentration between them and reducing expansion stress in the arc-shaped portion. This avoids issues such as purple spots and lithium plating in the arc-shaped portion, improving the cycle life of the wound cell and thus extending the life of the battery device. Furthermore, it facilitates the installation of the wound cell into the battery casing, which helps to increase the energy density of the battery device.

[0011] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and are not intended to limit this disclosure. Attached Figure Description

[0012] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this disclosure and, together with the description, serve to explain the principles of this disclosure. It is obvious that the drawings described below are merely some embodiments of this disclosure, and those skilled in the art can obtain other drawings based on these drawings without any inventive effort.

[0013] Figure 1 This is a schematic flowchart illustrating an example embodiment of the method for preparing a wound battery cell disclosed herein.

[0014] Figure 2 This is a schematic diagram of the structure of a first example embodiment of the method for preparing a wound battery cell disclosed herein.

[0015] Figure 3 This is a schematic diagram of the structure of a second exemplary embodiment of the method for preparing a wound battery cell disclosed herein.

[0016] Figure 4This is a schematic diagram of the third exemplary embodiment of the method for preparing a wound battery cell disclosed herein.

[0017] Figure 5 This is a schematic diagram of the winding structure formed by the method for preparing the wound battery cell disclosed herein.

[0018] Figure 6 This is a schematic diagram of the structure of the wound battery cell disclosed in this paper.

[0019] Explanation of reference numerals in the attached figures: 10. Film layer assembly to be wound; 20. Winding structure; 201. Flat section; 202. Curved section; 30. Functional ring layer; 1. First diaphragm; 2. First electrode; 3. Second diaphragm; 4. Second electrode; 5. Insulating board; 5a. First insulating board; 5b. Second insulating board; 5c. Third insulating board; 61. First feed roller; 62. Second feed roller; 63. Third feed roller; 64. Fourth feed roller; 65. Pressure roller; 66. Square coiling needle; X, the first direction. Detailed Implementation

[0020] Exemplary embodiments will now be described more fully with reference to the accompanying drawings. However, these exemplary embodiments can be implemented in many forms and should not be construed as limited to the embodiments set forth herein; rather, they are provided so that this disclosure will be thorough and complete, and will fully convey the concept of the exemplary embodiments to those skilled in the art. The same reference numerals in the drawings denote the same or similar structures, and therefore detailed descriptions of them will be omitted. Furthermore, the drawings are merely illustrative of this disclosure and are not necessarily drawn to scale.

[0021] Although relative terms such as "up" and "down" are used in this specification to describe the relative relationship of one component of an icon to another, these terms are used only for convenience, such as according to the orientation of the examples shown in the accompanying drawings. It is understood that if the device of the icon is flipped upside down, the component described as "up" will become the component described as "down." When a structure is "up" of another structure, it may mean that the structure is integrally formed on the other structure, or that the structure is "directly" mounted on the other structure, or that the structure is "indirectly" mounted on the other structure through another structure.

[0022] The terms “a,” “one,” “the,” “the,” and “at least one” are used to indicate the presence of one or more elements / components / etc.; the terms “including” and “having” are used to indicate an open-ended inclusion and to mean that there may be other elements / components / etc. in addition to the listed elements / components / etc.; the terms “first,” “second,” and “third,” etc., are used only as markers and are not a limitation on the number of objects.

[0023] In this application, unless otherwise expressly specified and limited, the term "connection" should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral part; it can be a direct connection or an indirect connection through an intermediate medium. "And / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Furthermore, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.

[0024] This disclosure provides an exemplary embodiment of a method for manufacturing a wound battery cell, referring to... Figures 1-5 As shown, the preparation method may include the following steps: Step S10: Provide a film layer assembly to be wound and multiple insulating plates. The film layer assembly to be wound includes a first diaphragm, a first electrode, a second diaphragm, and a second electrode stacked in sequence.

[0025] Step S20: The film layer group to be wound and the plurality of insulating plates are wound to form a winding structure. The winding structure has a flat portion and an arc-shaped portion, and the insulating plate is at least partially located in the arc-shaped portion.

[0026] Step S30: Remove the insulating plate.

[0027] The disclosed method for manufacturing a wound battery cell, on the one hand, involves an insulating plate 5 at least partially located in the arc-shaped portion 202. The structure of the arc-shaped portion 202 can be controlled via the insulating plate 5. For example, the insulating plate 5 can ensure the space between the first electrode 2 and the second electrode 4. Furthermore, different sizes of insulating plates 5 can be designed and selected according to the expansion degree of the wound battery cell, thereby ensuring different space sizes between the first electrode 2 and the second electrode 4, reducing the expansion stress of the arc-shaped portion 202, avoiding problems such as purple spots and lithium plating at the arc-shaped portion 202, and improving the cycle life of the wound battery cell. On the other hand, removing the insulating plate 5 to form the wound battery cell prevents the insulating plate 5 from affecting the lithium-ion transport between the first electrode 2 and the second electrode 4, ensuring the electrical performance of the wound battery cell; and also reduces the weight of the wound battery cell, increasing its energy density.

[0028] The following examples illustrate each step of the fabrication process for wound battery cells.

[0029] Step S10: Provide a film layer assembly to be wound and multiple insulating plates. The film layer assembly to be wound includes a first diaphragm, a first electrode, a second diaphragm, and a second electrode stacked in sequence.

[0030] The first electrode 2 and the second electrode 4 can be prepared first. The first electrode 2 can be a negative electrode. The first electrode 2 is made of copper foil, and a negative electrode active material is coated on the copper foil. The negative electrode active material is not coated at the position where the electrode tab is formed to form a blank area. The negative electrode active material can include graphite / silicon carbide material, conductive agent, binder (CMC / SBR), deionized water, etc.

[0031] The second electrode 4 can be a positive electrode. The second electrode 4 is made of aluminum foil, and a positive active material is coated on the aluminum foil. The positive active material is not coated at the position where the electrode tab is formed, forming a blank area. The positive active material can include active materials such as ternary / lithium iron phosphate, conductive agents, binders (such as PVDF), solvents (NMP), etc.

[0032] Then, drying and rolling are performed to achieve the designed compaction density of the first electrode 2 and the second electrode 4, enhancing the adhesion between the coating and the current collector and reducing internal resistance. Next, slitting and laser die-cutting are carried out. Slitting involves longitudinally cutting the electrode roll into narrow strips of a set width; laser die-cutting involves laser cutting the blank area to form electrode tabs; corner gaps can be cut out of the active material area as needed, suitable for the curved portion 202 of the shape-wound coil, to avoid excessively thick electrode stacking at the corners.

[0033] In some exemplary embodiments of this disclosure, providing the film layer group 10 to be wound and the plurality of insulating plates 5 may include: the insulating plates 5 being inserted starting when preparing to wind the Nth turn, where N is greater than or equal to 1; for example, the insulating plates 5 may be inserted starting when preparing to wind the 1st turn, or the insulating plates 5 may be inserted starting when preparing to wind the 2nd turn, without being inserted during the 1st turn; or the insulating plates 5 may be inserted starting when preparing to wind the 3rd turn, without being inserted during the 1st and 2nd turns.

[0034] It is permissible to place at least two insulating boards 5 per roll; for example, it is permissible to place two insulating boards 5 per roll or four insulating boards 5 per roll.

[0035] Alternatively, at least two insulating boards 5 can be placed inside after one turn of the winding. For example, it can be two or four insulating boards 5 placed inside after one turn of the winding. After winding M turns at intervals, at least two insulating boards 5 are placed inside again, where M is greater than or equal to 1. For example, it can be two or four insulating boards 5 placed inside after one turn at intervals (without placing insulating boards 5 in this turn), and so on; it can also be two or four insulating boards 5 placed inside after two turns at intervals (without placing insulating boards 5 in these two turns), and so on.

[0036] It should be noted that when two insulating plates 5 are placed after one turn of the winding, if the first insulating plate 5 is placed between the first diaphragm 1 and the first electrode 2, then every subsequent insulating plate 5 placed will be placed between the first diaphragm 1 and the first electrode 2; if the first insulating plate 5 is placed between the first electrode 2 and the second diaphragm 3, then every subsequent insulating plate 5 placed will be placed between the first electrode 2 and the second diaphragm 3. Of course, the first insulating plate 5 can also be placed in other positions, which will not be elaborated here.

[0037] When four insulating plates 5 are placed in a single winding, two of the insulating plates 5 form a pair, and the two insulating plates 5 belonging to a pair are located between the same film layers.

[0038] In some exemplary embodiments of this disclosure, reference is made to Figures 2-4 As shown, providing the film layer assembly 10 to be wound and multiple insulating plates 5 may include: providing a first diaphragm 1 via a first feed roller 61, i.e., the first diaphragm 1 is wound on the first feed roller 61, and the first feed roller 61 can rotate, so that the first diaphragm 1 can be unwound. Providing a first electrode 2 via a second feed roller 62, i.e., the first electrode 2 is wound on the second feed roller 62, and the second feed roller 62 can rotate, so that the first electrode 2 can be unwound. Providing a second diaphragm 3 via a third feed roller 63, i.e., the second diaphragm 3 is wound on the third feed roller 63, and the third feed roller 63 can rotate, so that the second diaphragm 3 can be unwound. Providing a second electrode 4 via a fourth feed roller 64, i.e., the second electrode 4 is wound on the fourth feed roller 64, and the fourth feed roller 64 can rotate, so that the second electrode 4 can be unwound.

[0039] Reference Figure 2As shown, the plurality of insulating plates 5 may include a plurality of first insulating plates 5a. For example, a portion of the plurality of insulating plates 5 may be first insulating plates 5a, or all of the plurality of insulating plates 5 may be first insulating plates 5a. The plurality of first insulating plates 5a are sequentially inserted between the first electrode 2 and the second electrode 4. For example, the plurality of first insulating plates 5a may be sequentially inserted between the first electrode 2 and the second diaphragm 3 by a feeding mechanism, or the plurality of first insulating plates 5a may be sequentially inserted between the second diaphragm 3 and the second electrode 4 by a feeding mechanism. The frequency of sequential insertion is such that two first insulating plates 5a are placed in one turn, so that two first insulating plates 5a are provided within one functional ring 30, and that both first insulating plates 5a are located at least in the arc-shaped portion 202, that is, the two first insulating plates 5a may be located only in the arc-shaped portion 202, or they may protrude slightly from the arc-shaped portion 202.

[0040] The first diaphragm 1, the first electrode 2, the second diaphragm 3, the second electrode 4, and the first insulating plate 5a are rolled together. Specifically, the first diaphragm 1, the first electrode 2, the second diaphragm 3, the second electrode 4, and the first insulating plate 5a are rolled together by two opposing pressure rollers 65. That is, the first insulating plate 5a is inserted first, and then the rolling of each membrane layer is performed.

[0041] In some exemplary embodiments of this disclosure, reference is made to Figure 3 As shown, the film layer assembly 10 to be wound and the plurality of insulating plates 5 may further include: the plurality of insulating plates 5 may also include a plurality of second insulating plates 5b. For example, a portion of the plurality of insulating plates 5 may be a first insulating plate 5a, and another portion of the plurality of insulating plates 5 may be a second insulating plate 5b. While the plurality of first insulating plates 5a are sequentially inserted between the first electrode 2 and the second electrode 4, the plurality of second insulating plates 5b are sequentially inserted between the first diaphragm 1 and the first electrode 2; that is, the first insulating plates 5a and the second insulating plates 5b can be inserted simultaneously by a feeding mechanism; the frequency of sequential insertion is that two first insulating plates 5a and two second insulating plates 5b are placed in one turn of the winding, so that two first insulating plates 5a and two second insulating plates 5b are provided in one functional ring 30, and that both the two first insulating plates 5a and the two second insulating plates 5b are at least located in the arc-shaped portion 202, that is, the two first insulating plates 5a and the two second insulating plates 5b may only be located in the arc-shaped portion 202, or they may slightly protrude from the arc-shaped portion 202. Then, the first diaphragm 1, the first electrode 2, the second diaphragm 3, the second electrode 4, and the first insulating plate 5a and the second insulating plate 5b are rolled together by two opposing pressure rollers 65. That is, the insertion of the first insulating plate 5a and the second insulating plate 5b is completed first, and then the rolling of each film layer is performed.

[0042] In some exemplary embodiments of this disclosure, reference is made to Figure 4As shown, providing the film layer assembly 10 to be wound and multiple insulating plates 5 may include: providing a first diaphragm 1 via a first feeding roller 61, providing a first electrode 2 via a second feeding roller 62, providing a second diaphragm 3 via a third feeding roller 63, and providing a second electrode 4 via a fourth feeding roller 64. The first diaphragm 1, the first electrode 2, the second diaphragm 3, and the second electrode 4 are rolled together to form the film layer assembly 10 to be wound. Specifically, the first diaphragm 1, the first electrode 2, the second diaphragm 3, and the second electrode 4 are rolled together by two opposing pressure rollers 65 to form the film layer assembly 10 to be wound. The multiple insulating plates 5 include multiple third insulating plates 5c. For example, a portion of the multiple insulating plates 5 may be a first insulating plate 5a, and another portion may be a third insulating plate 5c; alternatively, all of the multiple insulating plates 5 may be third insulating plates 5c. Multiple third insulating plates 5c are sequentially placed on one side of the film layer assembly 10 to be wound. Specifically, multiple third insulating plates 5c can be sequentially placed on one side of the film layer assembly 10 to be wound using a feeding mechanism. The frequency of sequential placement is two third insulating plates 5c placed for every one turn of the film layer, so that two third insulating plates 5c are provided within one functional ring layer 30, and that both third insulating plates 5c are located at least in the arc-shaped portion 202. That is, the two third insulating plates 5c can be located only in the arc-shaped portion 202, or they can protrude slightly from the arc-shaped portion 202. In other words, the rolling of each film layer is completed first, and then the placement of the third insulating plates 5c is performed.

[0043] In other exemplary embodiments of this disclosure, reference is made to Figure 4As shown, providing the film layer assembly 10 to be wound and multiple insulating plates 5 may include: providing a first diaphragm 1 via a first feeding roller 61, providing a first electrode 2 via a second feeding roller 62, providing a second diaphragm 3 via a third feeding roller 63, and providing a second electrode 4 via a fourth feeding roller 64. The first diaphragm 1, the first electrode 2, the second diaphragm 3, and the second electrode 4 are rolled together to form the film layer assembly 10 to be wound. Specifically, the first diaphragm 1, the first electrode 2, the second diaphragm 3, and the second electrode 4 are rolled together by two opposing pressure rollers 65 to form the film layer assembly 10 to be wound. The multiple insulating plates 5 include multiple third insulating plates 5c. For example, a portion of the multiple insulating plates 5 may be a first insulating plate 5a, and another portion may be a third insulating plate 5c; alternatively, all of the multiple insulating plates 5 may be third insulating plates 5c. Multiple third insulating plates 5c are sequentially placed on one side of the first side of the square winding needle 66. The first side is the side that forms the arc-shaped portion 202. Specifically, multiple third insulating plates 5c can be sequentially placed on one side of the first side of the square winding needle 66 by a feeding mechanism. The frequency of sequential placement is two third insulating plates 5c placed after one turn of winding, so that two third insulating plates 5c are provided within one functional ring layer 30, and both third insulating plates 5c are located at least in the arc-shaped portion 202. That is, the two third insulating plates 5c can be located only in the arc-shaped portion 202, or they can protrude slightly from the arc-shaped portion 202. That is, the rolling of each film layer is completed first, and then the placement of the third insulating plates 5c is performed.

[0044] Step S20: The film layer group to be wound and the plurality of insulating plates are wound to form a winding structure. The winding structure has a flat portion and an arc-shaped portion, and the insulating plate is at least partially located in the arc-shaped portion.

[0045] The insulating plate 5 is at least partially located in the arc-shaped portion 202. For example, the insulating plate 5 may be located only in the arc-shaped portion 202, or it may be slightly protruding from the arc-shaped portion 202, with a portion located in the flat portion 201. The structure of the arc-shaped portion 202 can be controlled by the insulating plate 5. For example, the insulating plate 5 can ensure the size of the space between the first electrode 2 and the second electrode 4. Moreover, different sizes of insulating plates 5 can be designed and selected according to the degree of expansion of the wound cell, thereby ensuring different sizes of space between the first electrode 2 and the second electrode 4, thereby reducing the expansion stress of the arc-shaped portion 202, avoiding problems such as purple spots and lithium plating at the location of the arc-shaped portion 202, and improving the cycle life of the wound cell.

[0046] In some exemplary embodiments of this disclosure, the first diaphragm 1 and the second diaphragm 3 can be released simultaneously. The front ends of the first diaphragm 1 and the second diaphragm 3 are drawn to the square winding needle 66. The square winding needle 66 can rotate at a small angle to first wind the first diaphragm 1 and the second diaphragm 3 one or two turns as a base, which can prevent the electrode sheet from directly contacting the square winding needle 66 and avoid defects such as short circuits and wrinkles. Alternatively, the front end of the first diaphragm 1 or the second diaphragm 3 can be drawn to the square winding needle 66, and the square winding needle 66 can rotate at a small angle to first wind the first diaphragm 1 or the second diaphragm 3 one or two turns as a base.

[0047] The first electrode 2 is fed out at a constant speed by the second feeding roller 62. The first electrode 2 is sandwiched between the first diaphragm 1 and the second diaphragm 3. The square winding needle 66 rotates, and the first diaphragm 1, the first electrode 2 and the second diaphragm 3 are wound together.

[0048] After the first electrode 2 is wound to a certain length, the second electrode 4 is fed. The second electrode 4 is positioned on the side of the second diaphragm 3 away from the first electrode 2. The square winding needle 66 rotates, and the first diaphragm 1, the first electrode 2, the second diaphragm 3, and the second electrode 4 are wound together, so that the second electrode 4 is also sandwiched between the first diaphragm 1 and the second diaphragm 3 after winding.

[0049] The insulating plate 5 can be inserted or placed after the second electrode 4 begins to be fed. During the first turn of winding, the first insulating plate 5a and the second insulating plate 5b can be inserted or placed for the second turn.

[0050] After the required length is achieved, the second electrode 4 is cut off first, followed by the first electrode 2, so that the first electrode 2 completely covers the second electrode 4. Finally, the first diaphragm 1 and the second diaphragm 3 are cut off, so that the first diaphragm 1 and the second diaphragm 3 completely cover the first electrode 2 and the second electrode 4. Then, finishing adhesive is applied. The adhesive application mechanism applies termination tape to the ends of the first diaphragm 1 and the second diaphragm 3. The tape can be high-temperature tape to prevent loosening and unraveling. The square winding needle 66 is then retracted to a smaller size, and the clamping hand removes the formed square winding structure 20.

[0051] During the winding process, the tension of the first electrode 2 is maintained between 5N and 20N, the tension of the second electrode 4 is maintained between 5N and 20N, the tension of the first diaphragm 1 is maintained between 2N and 5N, and the tension of the second diaphragm 3 is maintained between 2N and 5N.

[0052] The preparation method may also include hot-pressing and shaping the wound structure 20. For example, hot-pressing and shaping can be performed using a hot press, wherein the temperature is maintained between 70°C and 100°C, the pressure is maintained between 0.1 MPa and 1 MPa, and the duration is between 30 s and 120 s. Hot-pressing and shaping can expel internal air, make the diaphragm and the electrode sheet fit tightly together, eliminate wrinkles, shape it into a cuboid, ensure thickness consistency (deviation ≤ ±0.1 mm), and reduce internal resistance.

[0053] Step S30: Remove the insulating plate.

[0054] In some exemplary embodiments of this disclosure, the insulating plate 5 can be extracted by a robotic arm to form a wound battery cell.

[0055] The insulating plate 5 is pulled out to form a wound cell, which avoids the insulating plate 5 from affecting the transmission of lithium ions between the first and second electrodes, so as to ensure the electrical performance of the wound cell; and also reduces the weight of the wound cell and increases the energy density.

[0056] After the hot-pressed plate is shaped, the insulating plate 5 is pulled out to form a wound battery cell. This will not affect the space between the first electrode 2 and the second electrode 4, nor will it affect the cycle life of the wound battery cell.

[0057] The blank areas at both ends of the wound battery cell can be flattened to form a flat busbar surface; the tabs can be connected to the aluminum / copper busbar by ultrasonic welding or laser welding, and insulation treatment (e.g., applying high-temperature tape) can be performed after welding.

[0058] In some exemplary embodiments of this disclosure, the coefficient of friction of the insulating plate 5 is ≤0.5. For example, the coefficient of friction of the insulating plate 5 may be 0.1, 0.15, 0.2, 0.25, 0.3, 0.35, 0.4, 0.45, etc. Specifically, the coefficient of friction of the first insulating plate 5a is ≤0.5, the coefficient of friction of the second insulating plate 5b is ≤0.5, and the coefficient of friction of the third insulating plate 5c is ≤0.5.

[0059] If the coefficient of friction of the insulating plate 5 is too high, the friction between the insulating plate 5 and its adjacent film layers will be large, making it difficult to pull out the insulating plate 5. Even if the insulating plate 5 is pulled out, it will scratch the adjacent film layers, thereby affecting the electrical performance of the wound cell, and may even cause a short circuit between the first electrode 2 and the second electrode 4, resulting in the scrapping of the wound cell.

[0060] The above-mentioned numerical range results in low friction between the insulating plate 5 and its adjacent film layers, making it easy to pull out the insulating plate 5 without scratching the adjacent film layers, thus ensuring the electrical performance of the wound battery cell.

[0061] The flexural modulus of the insulating plate 5 is ≤100 GPa. For example, the flexural modulus of the insulating plate 5 can be 20 GPa, 40 GPa, 50 GPa, 70 GPa, 90 GPa, etc. Specifically, the flexural modulus of the first insulating plate 5a is ≤100 GPa, the flexural modulus of the second insulating plate 5b is ≤100 GPa, and the flexural modulus of the third insulating plate 5c is ≤100 GPa. Flexural modulus is the ability of a material to resist bending deformation. The larger the value, the harder the material and the less easily it is bent; the smaller the value, the softer the material and the easier it is to bend. If the bending modulus of the insulating plate 5 is too large, the insulating plate 5 will not be easy to bend, and even if it is bent, the bending stress will be large, which will affect the morphology of the arc-shaped part 202 and cause problems such as purple spots and lithium plating to easily appear at the position of the arc-shaped part 202.

[0062] The above-mentioned numerical range makes the insulating plate 5 easy to bend without affecting the shape of the arc-shaped part 202, avoiding problems such as purple spots and lithium plating at the position of the arc-shaped part 202, and improving the cycle life of the wound battery cell.

[0063] The tensile strength of insulating plate 5 is ≥100 MPa. For example, the tensile strength of insulating plate 5 can be 120 MPa, 150 MPa, 170 MPa, 200 MPa, 230 MPa, 250 MPa, 280 MPa, 300 MPa, etc. Specifically, the tensile strength of the first insulating plate 5a is ≥100 MPa, the tensile strength of the second insulating plate 5b is ≥100 MPa, and the tensile strength of the third insulating plate 5c is ≥100 MPa. Tensile strength is the maximum tensile force that a material can withstand before it breaks. The higher the value, the less likely it is to break; the lower the value, the easier it is to break.

[0064] If the tensile strength of the insulating plate 5 is too low, it will be easily broken during the winding process, which will affect the morphology of the arc-shaped part 202 and cause problems such as purple spots and lithium plating to easily appear at the position of the arc-shaped part 202.

[0065] The above-mentioned numerical range makes the insulating plate 5 less likely to be broken, does not affect the shape of the arc-shaped part 202, avoids problems such as purple spots and lithium plating at the position of the arc-shaped part 202, and improves the cycle life of the wound battery cell.

[0066] The materials of the insulating board 5 include, but are not limited to, polytetrafluoroethylene, polyetheretherketone, polyethylene, polypropylene, thermoplastic vulcanized rubber, thermoplastic polyurethane, and materials treated by plasma treatment or fluorinated coating technology.

[0067] In some exemplary embodiments of this disclosure, the thickness of the insulating plate 5 is greater than or equal to 15 micrometers and less than or equal to 50 micrometers. For example, the thickness of the insulating plate 5 can be 20 micrometers, 25 micrometers, 30 micrometers, 35 micrometers, 40 micrometers, 45 micrometers, etc. Specifically, the thickness of the first insulating plate 5a is greater than or equal to 15 micrometers and less than or equal to 50 micrometers, the thickness of the second insulating plate 5b is greater than or equal to 15 micrometers and less than or equal to 50 micrometers, and the thickness of the third insulating plate 5c is greater than or equal to 15 micrometers and less than or equal to 50 micrometers.

[0068] If the thickness of the insulating plate 5 is too small, it cannot meet the space requirements between the first electrode 2 and the second electrode 4, which will cause stress concentration between the first electrode 2 and the second electrode 4. This will lead to problems such as purple spots and lithium plating at the arc-shaped part 202, resulting in faster battery performance degradation.

[0069] If the insulation plate 5 is too thick, the space between the first electrode 2 and the second electrode 4 will be too large, which will make it difficult to install the wound cell into the battery case.

[0070] The above-mentioned numerical range ensures that the space between the first electrode 2 and the second electrode 4 is appropriate, which will not cause stress concentration between the first electrode 2 and the second electrode 4, thereby reducing the expansion stress of the arc-shaped part 202 and avoiding problems such as purple spots and lithium plating at the position of the arc-shaped part 202, thus improving the cycle life of the wound cell; it also facilitates the installation of the wound cell into the battery case.

[0071] In some exemplary embodiments of this disclosure, reference is made to Figure 4 As shown, during the winding process of a wound battery cell, the width of the multiple insulating plates 5 increases with the increase of winding time. With the increase of winding time, the thickness and width of the wound structure 20 formed by winding become larger, and the radius of the formed arc-shaped portion 202 also becomes larger. The increase in the width of the multiple insulating plates 5 with the increase of winding time ensures that the insulating plates 5 are at least located in the arc-shaped portion 202, preventing the arc-shaped portion 202 from being without insulating plates 5. This ensures that the space between the first electrode 2 and the second electrode 4 is maintained through the insulating plates 5, thereby reducing the expansion stress of the arc-shaped portion 202, avoiding problems such as purple spots and lithium plating at the location of the arc-shaped portion 202, and improving the cycle life of the wound battery cell.

[0072] Specifically, during the winding process of a wound battery cell, the width of the plurality of first insulating plates 5a inserted sequentially increases with the increase of winding time. During the winding process of a wound battery cell, the width of the plurality of second insulating plates 5b inserted sequentially increases with the increase of winding time. During the winding process of a wound battery cell, the width of the plurality of third insulating plates 5c placed sequentially increases with the increase of winding time.

[0073] It should be noted that the width of the insulating plate 5 is the length of the arc formed by the insulating plate 5 after it is wound up to form an arc-shaped structure.

[0074] In some exemplary embodiments of this disclosure, the ratio of the width of the insulating plate 5 to the arc length of the arc structure formed by the adjacent film layer is greater than or equal to 0.9 and less than or equal to 1.2. For example, the ratio of the width of the insulating plate 5 to the arc length of the arc structure formed by the adjacent film layer can be 0.93, 0.95, 0.98, 1, 1.02, 1.05, 1.07, 1.1, 1.13, 1.15, 1.18, etc.

[0075] If the ratio of the width of the insulating plate 5 to the arc length of the arc structure formed by the adjacent film layer is too small, there will be no insulating plate 5 in a large area of ​​the arc portion 202, which will not guarantee the space between the first electrode 2 and the second electrode 4. This will result in greater expansion stress in the arc portion 202, leading to problems such as purple spots and lithium plating.

[0076] If the ratio of the width of the insulating plate 5 to the arc length of the arc structure formed by the adjacent film layer is too large, the size of the portion of the insulating plate 5 located in the flat plate portion 201 will be too large, affecting the flatness of the flat plate portion 201.

[0077] The aforementioned numerical range ensures that the area of ​​the arc-shaped portion 202 without the insulating plate 5 is very small, thus guaranteeing that the space between the first electrode 2 and the second electrode 4 can be maintained through the insulating plate 5. This reduces the expansion stress of the arc-shaped portion 202, avoids problems such as purple spots and lithium plating at the location of the arc-shaped portion 202, and improves the cycle life of the wound battery cell. Moreover, the size of the portion of the insulating plate 5 located in the flat plate portion 201 is also very small, so it will not affect the flatness of the flat plate portion 201.

[0078] Specifically, the ratio of the width of the first insulating plate 5a to the arc length of the arc structure formed by the adjacent film layer is greater than or equal to 0.9 and less than or equal to 1.2; the ratio of the width of the second insulating plate 5b to the arc length of the arc structure formed by the adjacent film layer is greater than or equal to 0.9 and less than or equal to 1.2; and the ratio of the width of the third insulating plate 5c to the arc length of the arc structure formed by the adjacent film layer is greater than or equal to 0.9 and less than or equal to 1.2.

[0079] In some exemplary embodiments of this disclosure, the width of the insulating plate 5 is greater than or equal to 0.5 cm and less than or equal to 5 cm. For example, the width of the insulating plate 5 can be 1 cm, 1.5 cm, 2 cm, 2.5 cm, 3 cm, 3.5 cm, 4 cm, 4.5 cm, etc.

[0080] If the width of the insulating plate 5 is too small, it may result in a situation where there is no insulating plate 5 in part of the arc-shaped portion 202. This may not be able to ensure the space between the first electrode 2 and the second electrode 4, and may not be able to effectively reduce the expansion stress of the arc-shaped portion 202. Problems such as purple spots and lithium plating may appear at the position of the arc-shaped portion 202, reducing the cycle life of the wound battery cell.

[0081] If the width of the insulating plate 5 is too large, the length of the protruding arc-shaped portion 202 of the insulating plate 5 may be too long, thereby affecting the structure of the flat portion 201 of the winding structure 20 and thus affecting the performance of the winding structure 20.

[0082] The above-mentioned numerical range not only avoids the situation where the arc-shaped portion 202 is without the insulating plate 5, thus ensuring that the space between the first electrode 2 and the second electrode 4 can be maintained through the insulating plate 5, thereby reducing the expansion stress of the arc-shaped portion 202 and avoiding problems such as purple spots and lithium plating at the position of the arc-shaped portion 202, and improving the cycle life of the wound cell; but also the length of the insulating plate 5 protruding from the arc-shaped portion 202 is very small, so as not to affect the structure of the flat plate portion 201 of the winding structure 20, thus ensuring the performance of the winding structure 20.

[0083] Specifically, the width of the first insulating plate 5a is greater than or equal to 0.5 cm and less than or equal to 5 cm, the width of the second insulating plate 5b is greater than or equal to 0.5 cm and less than or equal to 5 cm, and the width of the third insulating plate 5c is greater than or equal to 0.5 cm and less than or equal to 5 cm.

[0084] In some exemplary embodiments of this disclosure, the dimension of the insulating plate 5 along the first direction X is larger than the dimension of the first diaphragm 1 along the first direction X. The dimension of the first diaphragm 1 along the first direction X can be equal to the dimension of the second diaphragm 3 along the first direction X, or the dimension of the first diaphragm 1 along the first direction X can be larger than the dimension of the second diaphragm 3 along the first direction X. The dimension of the second diaphragm 3 along the first direction X is larger than the dimension of the first electrode 2 along the first direction X, and the dimension of the second diaphragm 3 along the first direction X is larger than the dimension of the second electrode 4 along the first direction X. This ensures that after the winding structure 20 is formed, the insulating plate 5 protrudes from the other film layers in the first direction X, facilitating the clamping of the insulating plate 5 during subsequent extraction and preventing the robotic arm from contacting other film layers, avoiding wrinkles in other film layers, and preventing any impact on the performance of the winding structure 20.

[0085] Specifically, the dimension of the first insulating plate 5a along the first direction X is greater than the dimension of the first diaphragm 1 along the first direction X, the dimension of the second insulating plate 5b along the first direction X is greater than the dimension of the first diaphragm 1 along the first direction X, and the dimension of the third insulating plate 5c along the first direction X is greater than the dimension of the first diaphragm 1 along the first direction X.

[0086] It should be noted that the first direction X is the width direction of the first diaphragm 1, and the first direction X is perpendicular to the extension direction of the first diaphragm 1.

[0087] Alternatively, the two ends of the multiple insulating plates 5 can be flush, making it convenient for the robotic arm to grip and pull out the multiple insulating plates 5 together.

[0088] Of course, in some exemplary embodiments of this disclosure, the two ends of the plurality of insulating plates 5 along the first direction X can be staggered. For example, the two ends of the plurality of insulating plates 5 along the first direction X can form a stepped structure to increase the size of the first diaphragm 1.

[0089] In some exemplary embodiments of this disclosure, in the first direction X, one end of the insulating plate 5 extends beyond the first diaphragm 1 by a dimension greater than or equal to 2 cm and less than or equal to 5 cm. For example, in the first direction X, the dimension of one end of the insulating plate 5 extending beyond the first diaphragm 1 can be 2.3 cm, 2.5 cm, 2.8 cm, 3 cm, 3.2 cm, 3.5 cm, 3.7 cm, 4 cm, 4.3 cm, 4.5 cm, 4.8 cm, etc.

[0090] If the size of one end of the insulating plate 5 protruding from the first diaphragm 1 in the first direction X is too small, the robot arm will not be able to grip the insulating plate 5 easily, and the robot arm will easily come into contact with other film layers, causing other film layers to form wrinkles, which will affect the performance of the winding structure 20.

[0091] If one end of the insulating plate 5 protrudes too much from the first diaphragm 1 in the first direction X, the protruding part of the insulating plate 5 is prone to bending during the winding process, which will affect efficiency and yield.

[0092] Within the aforementioned numerical range, not only is it easy for the robotic arm to grip the insulating plate 5, but it is also less likely for the robotic arm to come into contact with other film layers, thus preventing other film layers from forming wrinkles and affecting the performance of the winding structure 20; moreover, the protruding insulating plate 5 is less likely to be bent during the winding process, thereby ensuring efficiency and yield.

[0093] Specifically, in the first direction X, one end of the first insulating plate 5a extends beyond the first diaphragm 1 by a dimension greater than or equal to 2 cm and less than or equal to 5 cm; one end of the second insulating plate 5b extends beyond the first diaphragm 1 by a dimension greater than or equal to 2 cm and less than or equal to 5 cm; and one end of the third insulating plate 5c extends beyond the first diaphragm 1 by a dimension greater than or equal to 2 cm and less than or equal to 5 cm.

[0094] In some exemplary embodiments of this disclosure, the dimension of the insulating plate 5 along the first direction X is greater than or equal to 5 cm and less than or equal to 50 cm. For example, the dimension of the insulating plate 5 along the first direction X can be 10 cm, 15 cm, 20 cm, 25 cm, 30 cm, 35 cm, 40 cm, 45 cm, etc.

[0095] Specifically, the first insulating plate 5a has a dimension of 5 cm or more and 50 cm or less along the first direction X, the second insulating plate 5b has a dimension of 5 cm or more and 50 cm or less along the first direction X, and the third insulating plate 5c has a dimension of 5 cm or more and 50 cm or less along the first direction X.

[0096] Of course, in some other exemplary embodiments of this disclosure, the two end faces of the insulating plate 5 along the first direction X may be flush with the two end faces of the arcuate portion 202 along the first direction X.

[0097] It should be noted that although the steps of the method for preparing the wound battery cell in this disclosure are described in a specific order in the accompanying drawings, this does not require or imply that these steps must be performed in that specific order, or that all the steps shown must be performed to achieve the desired result. Additional or alternative steps may be omitted, multiple steps may be combined into one step, and / or one step may be broken down into multiple steps.

[0098] Based on the same inventive concept, this disclosure provides an example embodiment of a wound battery cell, which is prepared by any of the preparation methods described above, with reference to... Figure 6 As shown, the wound battery cell may include a first separator 1, a first electrode 2, a second separator 3 and a second electrode 4 that are stacked and wound in sequence, and includes a flat plate portion 201 and an arc-shaped portion 202 connected to each other. In the arc-shaped portion 202, the distance between adjacent first electrode 2 and second electrode 4 is greater than or equal to 15 micrometers and less than or equal to 50 micrometers.

[0099] The wound cell disclosed herein provides a suitable space between the first electrode 2 and the second electrode 4, preventing stress concentration between them and reducing the expansion stress of the arc-shaped portion 202. This avoids problems such as purple spots and lithium plating at the arc-shaped portion 202, thus improving the cycle life of the wound cell. Furthermore, it facilitates the installation of the wound cell into the battery casing.

[0100] Specifically, the spacing between adjacent first electrode 2 and second electrode 4 can be 20 micrometers, 25 micrometers, 30 micrometers, 35 micrometers, 40 micrometers, 45 micrometers, etc.

[0101] If the spacing between adjacent first electrode 2 and second electrode 4 is too small, stress concentration will occur between the first electrode 2 and the second electrode 4, which will easily lead to problems such as purple spots and lithium plating at the arc-shaped part 202, resulting in faster battery performance degradation.

[0102] If the spacing between adjacent first electrode 2 and second electrode 4 is too large, the size of the wound cell will be too large, which will make it difficult to install the wound cell into the battery case.

[0103] The above-mentioned numerical range ensures that the space between the first electrode 2 and the second electrode 4 is appropriate, preventing stress concentration between the first electrode 2 and the second electrode 4, thereby reducing the expansion stress of the arc-shaped part 202, avoiding problems such as purple spots and lithium plating at the position of the arc-shaped part 202, improving the cycle life of the wound cell; and it is also beneficial to install the wound cell into the battery case.

[0104] In some exemplary embodiments of this disclosure, the wound battery cell may include multiple functional coils 30, which are connected and wound sequentially. Each functional coil 30 may include a first diaphragm 1, a first electrode 2, a second diaphragm 3, and a second electrode 4 stacked together. In the arcuate portion 202, the distance between the first electrode 2 and the second electrode 4 belonging to the same functional coil 30 is greater than or equal to 15 micrometers and less than or equal to 30 micrometers. For example, the distance between the first electrode 2 and the second electrode 4 belonging to the same functional coil 30 may be 18 micrometers, 20 micrometers, 22 micrometers, 25 micrometers, 27 micrometers, etc.

[0105] Since the first electrode 2 and the second electrode 4, which belong to the same functional layer 30, are rolled together by two relatively arranged pressure rollers 65, the distance between the first electrode 2 and the second electrode 4, which belong to the same functional layer 30, is smaller than the range mentioned above.

[0106] In some exemplary embodiments of this disclosure, the distance between the first electrode 2 and the second electrode 4 of the adjacent functional layer 30 is greater than or equal to 30 micrometers and less than or equal to 50 micrometers. For example, the distance between the first electrode 2 and the second electrode 4 of the adjacent functional layer 30 can be 33 micrometers, 35 micrometers, 38 micrometers, 40 micrometers, 42 micrometers, 45 micrometers, 47 micrometers, etc.

[0107] Since the two adjacent functional layers 30 are formed by winding, the distance between the first electrode 2 and the second electrode 4 of the adjacent functional layer 30 is larger than the range mentioned above.

[0108] Based on the same inventive concept, the present disclosure provides a battery device that may include any of the above-described wound battery cells. The specific structure of the wound battery cells has been described in detail, and therefore will not be repeated here.

[0109] The battery device disclosed herein has a spacing between adjacent first electrode 2 and second electrode 4 that is greater than or equal to and less than or equal to 1 / 2. This ensures that the space between the first electrode 2 and second electrode 4 is appropriate, preventing stress concentration between them and reducing the expansion stress of the arc-shaped portion 202. This avoids problems such as purple spots and lithium plating at the arc-shaped portion 202, improving the cycle life of the wound cell and thus increasing the lifespan of the battery device. Furthermore, it facilitates the installation of the wound cell into the battery casing, which is beneficial for increasing the energy density of the battery device.

[0110] The battery device can be a battery that stores chemical energy and converts it into electrical energy in a controllable manner. In a recyclable battery, the active materials can be activated by charging after discharge so that the battery can continue to be used. The battery includes a battery casing and a battery cell disposed inside the battery casing.

[0111] The battery device can be a battery pack, which may include a battery management system (BMS), a thermal management system, an electrical connection system (high voltage / low voltage connectors, wiring harnesses, etc.), structural components (casing, brackets, etc.) and protective components, etc., and the above components are placed in a box and sealed with a cover to form a complete functional unit that can directly output electrical energy.

[0112] The features, structures, or characteristics described above can be combined in any suitable manner in one or more embodiments, and the features discussed in the various embodiments are interchangeable where possible. In the above description, numerous specific details are provided to give a full understanding of embodiments of the invention. However, those skilled in the art will recognize that the technical solutions of the invention can be practiced without one or more of the specific details described, or other methods, components, materials, etc., can be employed. In other instances, well-known structures, materials, or operations are not shown or described in detail to avoid obscuring various aspects of the invention.

[0113] The terms “about” or “approximately” as used in this specification generally mean within 20%, preferably within 10%, and even more preferably within 5% of a given value or range. The quantities given here are approximate, meaning that unless otherwise specified, the meanings of “about,” “approximately,” “roughly,” or “approximately” are implied.

[0114] The terms "parallel" and "perpendicular" used in this application can mean not only perfectly parallel and perpendicular, but also have a certain margin of error; for example, if the angle between the two is greater than or equal to 0° and less than or equal to 5°, they are considered to be parallel; if the angle between the two is greater than or equal to 85° and less than or equal to 95°, they are considered to be perpendicular.

[0115] Other embodiments of this disclosure will readily occur to those skilled in the art upon consideration of the specification and practice of the invention disclosed herein. This application is intended to cover any variations, uses, or adaptations of this disclosure that follow the general principles of this disclosure and include common knowledge or customary techniques in the art not disclosed herein. The specification and examples are to be considered exemplary only, and the true scope and spirit of this disclosure are indicated by the appended claims.

Claims

1. A method for preparing a wound battery cell, characterized in that, include: A film layer assembly to be wound and multiple insulating plates are provided. The film layer assembly to be wound includes a first diaphragm, a first electrode, a second diaphragm, and a second electrode arranged in sequence. The film layer assembly to be wound and the plurality of insulating plates are wound to form a winding structure, the winding structure having a flat portion and an arc-shaped portion, and the insulating plates are at least partially located in the arc-shaped portion; Remove the insulating plate.

2. The method for preparing a wound battery cell according to claim 1, characterized in that, Provides the film layer assembly to be wound and multiple insulating plates, including: The insulating plate is inserted starting when the Nth turn is about to be wound, where N is greater than or equal to 1; At least two of the insulating plates are placed in each turn of the winding; or, at least two of the insulating plates are placed in each turn of the winding, and after winding M turns at intervals, at least two more of the insulating plates are placed in, where M is greater than or equal to 1.

3. The method for preparing a wound battery cell according to claim 2, characterized in that, Provides the film layer assembly to be wound and multiple insulating plates, including: The first diaphragm is provided by a first feed roller, the first electrode is provided by a second feed roller, the second diaphragm is provided by a third feed roller, and the second electrode is provided by a fourth feed roller. The plurality of insulating plates include a plurality of first insulating plates, and the plurality of first insulating plates are sequentially inserted between the first electrode and the second electrode; The first diaphragm, the first electrode, the second diaphragm, the second electrode, and the first insulating plate are rolled together.

4. The method for preparing a wound battery cell according to claim 3, characterized in that, The package includes a film layer assembly to be wound and multiple insulating plates, and also includes: The plurality of insulating plates include a plurality of second insulating plates. While the plurality of first insulating plates are sequentially inserted between the first electrode and the second electrode, the plurality of second insulating plates are sequentially inserted between the first diaphragm and the first electrode.

5. The method for preparing a wound battery cell according to claim 2 or 3, characterized in that, Provides the film layer assembly to be wound and multiple insulating plates, including: The first diaphragm is provided by a first feed roller, the first electrode is provided by a second feed roller, the second diaphragm is provided by a third feed roller, and the second electrode is provided by a fourth feed roller. The first diaphragm, the first electrode, the second diaphragm, and the second electrode are rolled together to form a film layer assembly to be wound. The plurality of insulating plates include a plurality of third insulating plates, which are placed sequentially on one side of the film layer assembly to be wound; or, the plurality of third insulating plates are placed sequentially on one side of a first side of a square winding needle, the first side being the side on which the arcuate portion is formed by winding.

6. The method for preparing a wound battery cell according to claim 1, characterized in that, Before removing the insulating plate, the preparation method further includes: The wound structure is then hot-pressed and shaped.

7. The method for preparing a wound battery cell according to claim 1, characterized in that, The insulating plate has a coefficient of friction of less than or equal to 0.5, and / or a flexural modulus of less than or equal to 100 GPa, and / or a tensile strength of greater than or equal to 100 MPa.

8. The method for preparing a wound battery cell according to claim 1, characterized in that, The thickness of the insulating plate is greater than or equal to 15 micrometers and less than or equal to 50 micrometers.

9. The method for preparing a wound battery cell according to claim 1, characterized in that, During the winding process of a wound battery cell, the width of the multiple insulating plates added increases with the increase of winding time.

10. The method for preparing a wound battery cell according to claim 9, characterized in that, The ratio of the width of the insulating plate to the arc length of the arc structure formed by the adjacent film layer is greater than or equal to 0.9 and less than or equal to 1.

2.

11. The method for preparing a wound battery cell according to claim 10, characterized in that, The width of the insulating plate is greater than or equal to 0.5 cm and less than or equal to 5 cm.

12. The method for preparing a wound battery cell according to claim 1, characterized in that, The dimension of the insulating plate along the first direction is greater than the dimension of the first diaphragm along the first direction, and the dimension of the first diaphragm along the first direction is greater than or equal to the dimension of the second diaphragm along the first direction, wherein the first direction is the width direction of the first diaphragm.

13. The method for preparing a wound battery cell according to claim 12, characterized in that, The plurality of insulating plates are arranged flush with both ends along the first direction, or the plurality of insulating plates are arranged staggered at both ends along the first direction.

14. The method for preparing a wound battery cell according to claim 12, characterized in that, In the first direction, one end of the insulating plate extends beyond the first diaphragm by a dimension greater than or equal to 2 cm and less than or equal to 5 cm.

15. The method for preparing a wound battery cell according to claim 1, characterized in that, The insulating plate is flush with the two end faces of the arc-shaped portion along the first direction, which is the width direction of the first diaphragm.

16. A wound battery cell, characterized in that, include: The first diaphragm, the first electrode, the second diaphragm, and the second electrode are stacked and wound together in sequence, and include a flat plate portion and an arc-shaped portion connected to each other. In the arc-shaped portion, the distance between adjacent first electrode and second electrode is greater than or equal to 15 micrometers and less than or equal to 50 micrometers.

17. The wound battery cell according to claim 16, characterized in that, The wound battery cell includes: The system comprises multiple functional coils, which are connected and wound sequentially. Each functional coil includes a first diaphragm, a first electrode, a second diaphragm, and a second electrode stacked together. In the arc-shaped portion, the distance between the first electrode and the second electrode belonging to the same functional coil is greater than or equal to 15 micrometers and less than or equal to 30 micrometers.

18. The wound battery cell according to claim 17, characterized in that, In the arc-shaped portion, the distance between the first electrode and the second electrode of the adjacent functional layer is greater than or equal to 30 micrometers and less than or equal to 50 micrometers.

19. A battery device, characterized in that, include: The wound battery cell according to any one of claims 16 to 18.

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