Winding battery cell, intermittent thermal composite winding device, lithium battery and battery pack

Abstract

The utility model provides a winding cell, an intermittent thermal compounding winding device, a lithium battery and a battery pack, and belongs to the technical field of batteries, the winding cell comprises a first composite sheet, a second composite sheet and a third composite sheet, the first composite sheet is formed by a first diaphragm and a positive plate through intermittent thermal compounding treatment; the second composite sheet is formed by a second diaphragm and a negative plate through intermittent thermal compounding treatment; the first composite sheet and the second composite sheet are wound to form a wound core body, and the wound core body is subjected to hot pressing treatment to form a wound battery cell. The device has the beneficial effects that the positive plate and the diaphragm as well as the negative plate and the diaphragm are subjected to thermal compounding treatment before winding, winding is performed after thermal compounding is completed, and then the positive plate and the diaphragm are fed into a hot-pressing station, so that the hot-pressing time can be greatly shortened, and the winding and hot-pressing efficiency is improved; and meanwhile, an intermittent thermal compounding process is adopted, so that high alignment precision during winding of the pole piece is ensured, and the problem of wrinkles caused by tension of a diaphragm in a bent area after winding is avoided.

Description

Technical Field

[0001] This utility model relates to the field of battery technology, and in particular to a wound battery cell, an intermittent thermal composite winding device, a lithium battery, and a battery pack. Background Technology

[0002] Square lithium battery cells are mainly manufactured through two processes: winding and stacking. The traditional winding process involves separately unwinding the positive electrode, the first separator, the negative electrode, and the second separator, then concentrating them on a winding needle to form a core body. The wound core body is then subjected to hot pressing to ensure the overall flatness and thickness of the wound cell.

[0003] However, traditional winding processes have the following problems: First, the position of the tabs on the electrode sheet relative to the winding needle is difficult to control, resulting in low positional accuracy of the positive and negative tabs in the produced wound cells. Second, due to the large amount of material strip involved in the winding process, and the fact that the beginning and end of the electrode sheet are not controlled by the correction mechanism, the alignment accuracy of the positive and negative electrode sheets during the winding process is low. Third, due to the tension of the separator, the wound cell is prone to S-shaped bends in the bending area, making it difficult to guarantee winding accuracy, which directly affects the quality of the cell. In addition, the positive electrode sheet, the first separator, the negative electrode sheet, and the second separator require many auxiliary mechanical actions during the winding process, which not only increases the complexity of the process but also affects the production efficiency of the equipment. Finally, in order to achieve the composite effect of the electrode sheet and the separator, the core body needs to undergo a long period of hot pressing after winding, further reducing the overall production efficiency. Utility Model Content

[0004] To solve the above technical problems, this utility model provides a wound battery cell; secondly, it also provides an intermittent thermal composite winding device; thirdly, it also provides a lithium battery; and fourthly, it also provides a battery pack.

[0005] The technical problem solved by this utility model can be achieved by the following technical solution:

[0006] The first aspect of this utility model is to provide a wound battery cell, comprising:

[0007] The first composite sheet is formed by intermittent thermal bonding of a first separator and a positive electrode sheet.

[0008] The second composite sheet is formed by intermittent thermal bonding of the second separator and the negative electrode sheet;

[0009] The first composite sheet and the second composite sheet are wound together to form a core body, and the core body is hot-pressed to form a wound cell.

[0010] Preferably, the first composite sheet and the second composite sheet have multiple thermally bonded regions, which are spaced apart. The thermally bonded regions are areas on the wound cell other than the bending areas.

[0011] A second aspect of this invention is to provide an intermittent thermal composite winding apparatus for preparing wound battery cells as described above, the apparatus comprising:

[0012] A winding station is used to wind a first composite sheet and a second composite sheet to form a core body, wherein the first composite sheet is formed by intermittent thermal bonding of a first diaphragm and a positive electrode sheet, and the second composite sheet is formed by intermittent thermal bonding of a second diaphragm and a negative electrode sheet.

[0013] A hot pressing station is located downstream of the winding station. The hot pressing station is used to perform hot pressing treatment on the core body to form a wound cell.

[0014] Preferably, it further includes:

[0015] A thermal bonding station is located upstream of the winding station. The thermal bonding station is used to intermittently thermally bond the positive electrode sheet and the first separator to form the first composite sheet, and to thermally bond the negative electrode sheet and the second separator to form the second composite sheet.

[0016] Preferably, the thermal composite station includes:

[0017] A first thermal bonding plate and a second thermal bonding plate are arranged in parallel with each other, and a channel for the electrode sheet and the diaphragm to pass through is formed between the first thermal bonding plate and the second thermal bonding plate.

[0018] The driving mechanism is electrically connected to the first thermal composite plate and the second thermal composite plate respectively, so as to drive the first thermal composite plate and the second thermal composite plate to move closer or further apart.

[0019] Preferably, the first composite sheet and the second composite sheet have multiple thermally bonded regions, which are spaced apart. The thermally bonded regions are areas on the wound cell other than the bending areas.

[0020] Preferably, the dimensions of the first thermal bonding plate and the second thermal bonding plate are the same as the dimensions of the thermal bonding area.

[0021] Preferably, it further includes:

[0022] The first unwinding mechanism is used to output the positive electrode sheet;

[0023] The second unwinding mechanism is used to output the first diaphragm, and the second unwinding mechanism operates synchronously with the first unwinding mechanism.

[0024] The third unwinding mechanism is used to output the negative electrode sheet;

[0025] The fourth unwinding mechanism is used to output the second diaphragm, and the fourth unwinding mechanism operates synchronously with the third unwinding mechanism.

[0026] A third aspect of this utility model is to provide a lithium battery, including the wound cell as described above or the wound cell obtained by winding using the intermittent thermal composite winding device as described above.

[0027] A fourth aspect of this invention is to provide a battery pack comprising the lithium battery described above.

[0028] The advantages or beneficial effects of this utility model's technical solution are as follows:

[0029] This invention involves thermally bonding the positive electrode sheet and the separator, and the negative electrode sheet and the separator separately before winding, followed by winding after thermal bonding, and then sending them to the hot pressing station. Compared with the traditional solution that achieves the bonding effect of the electrode sheet and the separator during the hot pressing process, this invention can significantly reduce the hot pressing time and improve the winding and hot pressing efficiency. At the same time, the intermittent thermal bonding process ensures high alignment accuracy during electrode winding and avoids wrinkles caused by the tension of the separator in the bending area after winding, thus improving product quality. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of an intermittent thermal composite winding device in a preferred embodiment of the present invention.

[0031] Figure 2 This is a schematic diagram of the structure of the thermal composite station in a preferred embodiment of the present invention.

[0032] Figure 3 This is a schematic diagram of the core body after it has been unfolded, which is a preferred embodiment of the present invention.

[0033] Explanation of reference numerals in the attached figures:

[0034] 1. Positive electrode sheet; 2. First separator; 3. Negative electrode sheet; 4. Second separator; 5. First composite sheet; 6. Second composite sheet; 7. Core body; 8. Winded cell; 9. First unwinding mechanism; 10. Second unwinding mechanism; 11. Third unwinding mechanism; 12. Fourth unwinding mechanism; 13. Thermal bonding station; 13a. First thermal bonding station; 13b. Second thermal bonding station; 14. Winding station; 15. Hot pressing station; A1. First thermal bonding plate; A2. Second thermal bonding plate; A3. Separator; A4. Electrode sheet; B1. Tab; B2. Thermal bonding area; B3. Non-thermal bonding area. Detailed Implementation

[0035] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0036] It should be noted that, unless otherwise specified, the embodiments and features described in these embodiments can be combined with each other.

[0037] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, but this is not intended to limit the present invention.

[0038] Example 1

[0039] In a preferred embodiment of this utility model, based on the above-mentioned problems existing in the prior art, a wound battery cell is now provided, such as... Figure 1 As shown, it includes:

[0040] The first composite sheet 5 is formed by intermittent thermal bonding of the first separator 2 and the positive electrode sheet 1.

[0041] The second composite sheet 6 is formed by intermittent thermal bonding of the second diaphragm 2 and the negative electrode sheet 3.

[0042] The first composite sheet 5 and the second composite sheet 6 are wound together to form a core body 7, and the core body 7 is hot-pressed to form a wound cell 8.

[0043] Specifically, in the traditional winding process, the winding-hot pressing method results in poor positional accuracy of the positive and negative electrode tabs and low alignment accuracy of the positive and negative electrode sheets. Furthermore, diaphragm tension causes the battery cell to bend in an S-shape in the bending area, and the process itself is complex and inefficient.

[0044] In this embodiment, the winding process is improved by adopting a thermal bonding-winding-hot pressing method. In the traditional winding process, the positive electrode sheet, first separator, negative electrode sheet, and second separator are separately unwound and then wound onto a winding needle. After winding, the thermal bonding effect of the positive electrode sheet 1, first separator 2, negative electrode sheet 3, and second separator 4 is achieved in the hot pressing step. Unlike the traditional winding process, the winding process in this embodiment advances the thermal bonding step to before winding. Specifically, before winding, the positive electrode sheet 1 and the first separator 2 are thermally bonded to form the first composite sheet 5, and the negative electrode sheet 3 and the second separator 4 are thermally bonded to form the second composite sheet 6. After thermal bonding, winding is performed, and then the sheets are sent to the hot pressing station 15 for hot pressing. Since the thermal bonding effect between the electrode sheet and the separator is completed before hot pressing, the hot pressing time is greatly reduced, and the hot pressing efficiency is improved.

[0045] Because the thermal bonding between the electrode and the separator is completed before winding, and an intermittent thermal bonding process is used, extremely high alignment accuracy of the electrode is ensured during winding, thus effectively improving winding efficiency. At the same time, it avoids wrinkling problems caused by separator tension in the bending area after winding, thereby improving product quality.

[0046] More specifically, such as Figure 3 As shown, the wound cell 8 also includes a tab B1. Tab B1 is a bridge connecting the internal and external circuits of the battery, capable of conducting the electrical energy generated by the positive and negative electrode active materials inside the battery to external electrical appliances or charging devices.

[0047] The electrode B1 includes a positive electrode tab disposed on the positive electrode plate 1 and a negative electrode tab disposed on the negative electrode plate 3. Specifically, the positive electrode tab draws out the current generated by the positive electrode active material, and the negative electrode tab draws out the current generated by the negative electrode active material, allowing the battery to exchange electrical energy with the external environment. The electrode tabs are usually made of materials with good conductivity, such as copper and aluminum, to ensure efficient current transmission and low resistance, reduce energy loss, and thus ensure that the battery can operate stably and reliably.

[0048] In a preferred embodiment, such as Figure 3 As shown, the first composite sheet 5 and the second composite sheet 6 have multiple thermal composite regions B2, which are spaced apart. The thermal composite regions B2 are the regions on the wound cell 8 other than the bending region.

[0049] Specifically, in this embodiment, several thermally composited regions B2 are distributed on the first composite sheet 5 and the second composite sheet 6, respectively. These thermally composited regions B2 are arranged at certain intervals. Furthermore, the thermally composited regions B2 cover all areas on the wound cell 8 except for the bending area.

[0050] More specifically, the first composite sheet 5 and the second composite sheet 6 also have multiple non-thermal composite regions B3, which are arranged alternately with the aforementioned thermal composite regions B2. The non-thermal composite regions B3 are the bending regions on the wound cell 8.

[0051] It should be noted that, for clarity, in this embodiment, length refers to the dimension along the winding direction, and width refers to the dimension perpendicular to the winding direction.

[0052] More specifically, the position and size of the thermally bonded region B2 on the first composite sheet 5 correspond one-to-one with the position and size of the thermally bonded region B2 on the second composite sheet 6. Similarly, the position and size of the non-thermally bonded region B3 on the two composite sheets also correspond one-to-one.

[0053] More specifically, for a single composite sheet, multiple thermally bonded regions B2 have the same length, and their width is less than or equal to the width of the strip (i.e., the electrode or diaphragm).

[0054] More specifically, for a single composite sheet, the dimensions of multiple non-thermal composite regions B3 can be the same or different. For example, the dimensions of multiple non-thermal composite regions B3 may increase sequentially along the winding direction. Specifically, this applies to the bending area of ​​a square wound cell. During the manufacturing process of a square wound cell, due to the special structure and process requirements of the bending area, the dimensions of the non-thermal composite regions B3 gradually increase along the length direction to better adapt to the bending characteristics of the square wound cell. This allows for more effective handling of issues related to the bending area during the winding process, improving the manufacturing quality and performance stability of the cell.

[0055] like Figure 3 As shown, before the winding step, the positive electrode sheet 1 and the first separator 2 are simultaneously unwound and then enter the thermal bonding station. At the thermal bonding station, intermittent thermal bonding operations are performed, thereby forming spaced thermal bonding regions B2 on the first composite sheet after thermal bonding. Thermal bonding region B2 is the processing area of ​​the thermal bonding station, which is equivalent to the large surface area of ​​the core body 7, i.e., the area other than the bending area. Non-thermal bonding region B3 is the area that is not thermally bonded at the thermal bonding station; this area is equivalent to the bending area in the core body 7.

[0056] By employing intermittent thermal bonding, it is possible to ensure that the separator in the bending area can reduce wrinkling when the cell sheet enters the winding process after thermal bonding, thereby improving the quality and stability of the entire battery production process.

[0057] Example 2

[0058] This invention also provides an intermittent thermal composite winding device for preparing wound battery cells as described above. Figure 1 As shown, the device includes:

[0059] The winding station 14 is used to wind the first composite sheet 5 and the second composite sheet 6 to form the core body 7. The first composite sheet 5 is formed by intermittent thermal bonding of the first diaphragm 2 and the positive electrode sheet 1, and the second composite sheet 6 is formed by intermittent thermal bonding of the second diaphragm 4 and the negative electrode sheet 3.

[0060] The hot pressing station 15 is located downstream of the winding station 14. The hot pressing station 15 is used to hot press the core body 7 to form the wound cell 8.

[0061] Specifically, addressing the problems of low positional accuracy of the positive and negative electrode tabs, low alignment accuracy of the positive and negative electrode sheets, S-shaped bending in the bending area due to diaphragm tension, complex process, and low efficiency in traditional winding processes, this embodiment improves the winding process. The hot pressing method is changed from the traditional method of hot pressing after winding to hot bonding the positive electrode sheet 1 with the first diaphragm 2 and the negative electrode sheet 3 with the second diaphragm 4 before winding. After hot bonding, they are sent together to the winding station 14 for winding and finally to the hot pressing station 15. Since the hot bonding effect between the electrode sheet and the diaphragm is completed before hot pressing, the hot pressing time can be significantly reduced, and the hot pressing efficiency can be improved.

[0062] More specifically, the winding station 14 mainly includes a winding needle. After the thermal bonding process is completed, the needle is fed into the winding station 14 to wind the first composite sheet 5 and the second composite sheet 6 to form the core body 7. Since the thermal bonding effect between the electrode and the separator is completed before winding, and the thermal bonding process is intermittent, the non-thermal bonding area B3 corresponds to the bending area in the core body 7, and the non-thermal bonding area B3 corresponds to other areas except the bending area. This ensures that the electrode has extremely high alignment accuracy during winding, which can significantly improve winding and hot pressing efficiency.

[0063] Meanwhile, the non-thermal composite area B3 is not thermally composited, which avoids wrinkling problems caused by the tension of the separator in the bending area after winding, thereby improving the quality and stability of the entire battery production process and enhancing product quality.

[0064] In a preferred embodiment, such as Figure 2 As shown, it also includes:

[0065] The thermal bonding station 13 is located upstream of the winding station 14. The thermal bonding station 13 is used to intermittently thermally bond the positive electrode 1 and the first separator 2 to form the first composite sheet 5, and to thermally bond the negative electrode 3 and the second separator 4 to form the second composite sheet 6.

[0066] Specifically, the thermal bonding station 13 is used to thermally bond the electrode A4 and the separator A3, wherein the electrode A4 is one of the positive electrode 1 and the negative electrode 3, and the separator A3 is one of the first separator 2 and the second separator 4, so as to obtain the first composite sheet 5 formed by thermally bonding the positive electrode 1 and the first separator 2, and the second composite sheet 6 formed by thermally bonding the negative electrode 3 and the second separator 4.

[0067] More specifically, the thermal bonding of the positive electrode 1 with the first separator 2 and the thermal bonding of the negative electrode 3 with the second separator 4 can be achieved using the same thermal bonding station 13.

[0068] More specifically, the thermal bonding of the positive electrode 1 with the first separator 2 and the thermal bonding of the negative electrode 3 with the second separator 4 can also be achieved using separate stations. For example, the thermal bonding station 13 includes a first thermal bonding station 13a and a second thermal bonding station 13b. The first thermal bonding station 13a is used to achieve the thermal bonding of the positive electrode 1 with the first separator 2, and the second thermal bonding station 13b is used to achieve the thermal bonding of the negative electrode 3 with the second separator 4.

[0069] In a preferred embodiment, such as Figure 2 As shown, the thermal composite station 13 includes:

[0070] A first thermal composite plate A1 and a second thermal composite plate A2 are arranged in parallel with each other, and a channel is formed between the first thermal composite plate A1 and the second thermal composite plate A2 for the electrode A4 and the diaphragm A3 to pass through.

[0071] The driving mechanism (not shown in the figure) is electrically connected to the first thermal composite plate A1 and the second thermal composite plate A2 respectively, so as to drive the first thermal composite plate A1 and the second thermal composite plate A2 to move closer or further apart.

[0072] Specifically, in this embodiment, the thermal bonding station 13 includes a first thermal bonding plate A1, a second thermal bonding plate A2, and a driving mechanism. The first thermal bonding plate A1 and the second thermal bonding plate A2 are arranged opposite to each other and parallel to each other, forming a channel between them. The function of this channel is to allow the electrode A4 and the diaphragm A3 to pass through.

[0073] More specifically, the driving mechanism can be set to a single unit. A single driving mechanism simultaneously applies force to the first thermal bonding plate A1 and the second thermal bonding plate A2, causing the two thermal bonding plates to move closer to each other, i.e., gradually approaching each other to achieve the thermal bonding process; or it applies opposite forces, causing the two to move away from each other, i.e., gradually separating.

[0074] More specifically, the drive mechanism can be configured to correspond one-to-one with the first thermal composite pressure plate A1 and the second thermal composite pressure plate A2. Two independent drive mechanisms are connected to the first thermal composite pressure plate A1 and the second thermal composite pressure plate A2 respectively, controlling their relative movement towards or away from each other.

[0075] The drive mechanism can be electrically driven, for example, by using an electric motor. However, it should be understood that it is not limited to electric drive; in other embodiments, other drive elements or devices can be used to achieve the same driving effect, such as hydraulic or pneumatic drive.

[0076] More specifically, under the driving action of the drive mechanism, the first thermal bonding plate A1 and the second thermal bonding plate A2 are controlled in a cyclical alternation pattern of approaching, moving away, approaching, and moving away. Through this cyclical alternation, an intermittent thermal bonding effect can be achieved between the electrode A4 and the diaphragm A3.

[0077] When the first thermal composite plate A1 and the second thermal composite plate A2 approach each other, the electrode A4 and the diaphragm A3 passing through the channel between the two plates will be thermally composited, forming a thermal composite area B2 on the composite sheet. This area is the area that is pressed together by the thermal composite plate.

[0078] Then, the first thermal composite plate A1 and the second thermal composite plate A2 are controlled to move away from each other and remain in this state for a period of time. At this time, the corresponding area on the composite sheet is the non-thermal composite area B3, that is, the area that is not pressed by the thermal composite plate.

[0079] Subsequently, the first thermal bonding plate A1 and the second thermal bonding plate A2 are brought closer together again to form the next thermal bonding area B2 on the composite sheet. This process is repeated to complete the thermal bonding process, thereby forming an intermittently thermally bonded composite sheet.

[0080] More specifically, the duration for which the first thermal bonding plate A1 and the second thermal bonding plate A2 are far apart from each other can be the same or different. For example, the duration can increase sequentially, so that the size of the non-thermal bonding region B3 can gradually increase along the winding direction, thereby adapting to the bending characteristics of the square wound cell.

[0081] The thermal bonding process, at thermal bonding station 13, involves heating and pressurizing to achieve a tight bond between the electrode and the separator, enhancing the stability of the internal structure of the cell and improving its energy density and cycle life. Simultaneously, it reduces deformation and twisting of the cell due to internal stress during charging and discharging, thereby improving the cell's safety and performance.

[0082] The hot pressing process is carried out at the hot pressing station 15, where the wound composite sheet is further compacted by heating and pressurizing, which further increases the compactness of the internal structure of the battery cell and improves the energy density of the battery cell.

[0083] Both the hot bonding process and the hot pressing process use heating and pressurization. The heating and pressurization parameters, such as temperature, applied pressure, heating time, and pressurization time, are set according to specific requirements.

[0084] The hot pressing station 15 is also implemented using two pressure plates, which are close to each other for hot pressing. For example, the hot pressing station 15 can share the same station with the aforementioned hot bonding station 13. After winding is completed at the winding station 14, it returns to the hot bonding station 13 to implement the hot pressing process parameters and achieve hot pressing treatment.

[0085] In a preferred embodiment, the first composite sheet 5 and the second composite sheet 6 have multiple thermal composite regions B2, which are spaced apart. The thermal composite regions B2 are other regions on the wound cell 8 except for the bending region.

[0086] Specifically, in this embodiment, through the thermal bonding process, several thermal bonding regions B2 and non-thermal bonding regions B3 are distributed on the first composite sheet 5 and the second composite sheet 6, respectively, and the thermal bonding regions B2 and non-thermal bonding regions B3 are arranged alternately.

[0087] Several thermally composite regions B2 are set at a certain interval, which is the length of the non-thermally composite region B3.

[0088] The non-thermal composite region B3 corresponds to the bending region on the wound cell 8, while the thermal composite region B2 corresponds to the other regions on the wound cell 8 besides the bending region.

[0089] More specifically, the position and size of the thermally bonded region B2 on the first composite sheet 5 correspond one-to-one with the position and size of the thermally bonded region B2 on the second composite sheet 6. Similarly, the position and size of the non-thermally bonded region B3 on the two composite sheets also correspond one-to-one.

[0090] More specifically, for a single composite sheet, multiple thermally bonded regions B2 have the same length, and their width is less than or equal to the width of the strip (i.e., the electrode or diaphragm).

[0091] More specifically, for a single composite sheet, the dimensions of multiple non-thermal composite regions B3 can be the same or different. For example, the dimensions of multiple non-thermal composite regions B3 may increase sequentially along the winding direction. Specifically, this applies to the bending area of ​​a square wound cell. During the manufacturing process of a square wound cell, due to the special structure and process requirements of the bending area, the dimensions of the non-thermal composite regions B3 gradually increase along the length direction to better adapt to the bending characteristics of the square wound cell. This allows for more effective handling of issues related to the bending area during the winding process, improving the manufacturing quality and performance stability of the cell.

[0092] In a preferred embodiment, the dimensions of the first thermal bonding plate A1 and the second thermal bonding plate A2 are the same as the dimensions of the thermal bonding region B2.

[0093] In a preferred embodiment, it further includes:

[0094] The first unwinding mechanism 9 is used to output the positive electrode plate 1;

[0095] The second unwinding mechanism 10 is used to output the first diaphragm 2. The second unwinding mechanism 10 operates synchronously with the first unwinding mechanism 9 to ensure the synchronous output of the positive electrode 1 and the first diaphragm 2.

[0096] The third unwinding mechanism 11 is used to output the negative electrode 3;

[0097] The fourth unwinding mechanism 12 is used to output the second diaphragm 4. The fourth unwinding mechanism 12 operates synchronously with the third unwinding mechanism 11 to ensure the synchronous output of the negative electrode 3 and the second diaphragm 4.

[0098] Specifically, in the wound cell, a separator is placed between the positive electrode 1 and the negative electrode 3, and the positive electrode 1 is thermally bonded to the first separator 2, while the negative electrode 3 is thermally bonded to the second separator 4. In this embodiment, the second unwinding mechanism 10 is placed adjacent to the first unwinding mechanism 9, and the third unwinding mechanism 11 is placed adjacent to the fourth unwinding mechanism 12.

[0099] The second unwinding mechanism 10 and the fourth unwinding mechanism 12 are not placed adjacent to each other. For example, the first unwinding mechanism 9 is placed between the second unwinding mechanism 10 and the fourth unwinding mechanism 12, or the third unwinding mechanism 11 can be placed between the second unwinding mechanism 10 and the fourth unwinding mechanism 12.

[0100] In the thermal bonding process, the positive electrode 1 output by the first unwinding mechanism 9 and the first diaphragm 2 output by the second unwinding mechanism 10 run synchronously. When they reach the thermal bonding station 13, the positive electrode 1 and the first diaphragm 2 can correspond, which facilitates the thermal bonding operation.

[0101] Similarly, the negative electrode 3 output by the third unwinding mechanism 11 and the second diaphragm 4 output by the fourth unwinding mechanism 12 operate synchronously. When they reach the thermal bonding station 13, the negative electrode 3 and the second diaphragm 4 can also correspond, which facilitates the thermal bonding operation of the negative electrode 3 and the second diaphragm 4.

[0102] More specifically, the first unwinding mechanism 9, the second unwinding mechanism 10, the third unwinding mechanism 11 and the fourth unwinding mechanism 12 each include at least one driving device for controlling the output speed and tension of the corresponding electrode or diaphragm.

[0103] More specifically, each unwinding mechanism 9 can also be equipped with a corresponding guiding device to adjust the output path of the electrode and the diaphragm, ensuring their alignment and flatness before entering the thermal bonding process.

[0104] Example 3

[0105] This utility model also provides a lithium battery, including a wound cell 8 as described in Embodiment 1 above, or a wound cell 8 obtained by using an intermittent thermal composite winding device as described in Embodiment 2 above.

[0106] Specifically, a lithium battery is a type of battery that uses lithium metal or lithium alloy as the negative electrode material and a non-aqueous electrolyte solution. It has advantages such as high energy density, small size, and light weight, and is widely used in portable electronic devices, electric vehicles, and other fields.

[0107] Among them, the wound cell 8 is housed inside the lithium battery casing.

[0108] More specifically, the lithium battery is a square lithium battery. When the wound cell 8 is wound and formed, it is roughly racetrack-shaped and housed in a casing. After the casing is filled with electrolyte and sealed, a square lithium battery is formed.

[0109] Example 4

[0110] This utility model also provides a battery pack, including the lithium battery as described above.

[0111] A battery pack is a single unit that combines multiple lithium-ion batteries or other types of batteries with a corresponding battery management system (BMS), casing, and other components. Battery packs can provide power to various electronic devices or vehicles, offering higher voltage and capacity to meet more complex power demands.

[0112] The advantages or beneficial effects of the above technical solution are as follows: This utility model performs thermal bonding treatment on the positive electrode sheet and the separator, and the negative electrode sheet and the separator respectively before winding, and then winds them after thermal bonding, and then sends them to the hot pressing station. Compared with the traditional solution of achieving the bonding effect of the electrode sheet and the separator in the hot pressing process, it can significantly reduce the hot pressing time and improve the winding and hot pressing efficiency. At the same time, the intermittent thermal bonding process ensures high alignment accuracy during electrode sheet winding, avoids wrinkles caused by the tension of the separator in the bending area after winding, and improves product quality.

[0113] The above are merely preferred embodiments of the present utility model and are not intended to limit the implementation methods and protection scope of the present utility model. Those skilled in the art should realize that any equivalent substitutions and obvious changes made using the content of this specification and illustrations should be included within the protection scope of the present utility model.

Claims

1. A wound battery cell, characterized in that, include: The first composite sheet is formed by intermittent thermal bonding of a first separator and a positive electrode sheet. The second composite sheet is formed by intermittent thermal bonding of the second separator and the negative electrode sheet; The first composite sheet and the second composite sheet are wound together to form a core body, and the core body is hot-pressed to form a wound cell.

2. The wound battery cell according to claim 1, characterized in that, The first composite sheet and the second composite sheet have multiple thermally bonded regions, which are spaced apart. The thermally bonded regions are the areas on the wound cell other than the bending areas.

3. An intermittent thermal composite winding device, characterized in that, The apparatus for manufacturing a wound battery cell as described in any one of claims 1-2, the apparatus comprising: A winding station is used to wind a first composite sheet and a second composite sheet to form a core body, wherein the first composite sheet is formed by intermittent thermal bonding of a first diaphragm and a positive electrode sheet, and the second composite sheet is formed by intermittent thermal bonding of a second diaphragm and a negative electrode sheet. A hot pressing station is located downstream of the winding station. The hot pressing station is used to perform hot pressing treatment on the core body to form a wound cell.

4. The intermittent thermal composite winding device according to claim 3, characterized in that, Also includes: A thermal bonding station is located upstream of the winding station. The thermal bonding station is used to intermittently thermally bond the positive electrode sheet and the first separator to form the first composite sheet, and to thermally bond the negative electrode sheet and the second separator to form the second composite sheet.

5. The intermittent thermal composite winding device according to claim 4, characterized in that, The thermal bonding station includes: A first thermal bonding plate and a second thermal bonding plate are arranged in parallel with each other, and a channel for the electrode sheet and the diaphragm to pass through is formed between the first thermal bonding plate and the second thermal bonding plate. The driving mechanism is electrically connected to the first thermal composite plate and the second thermal composite plate respectively, so as to drive the first thermal composite plate and the second thermal composite plate to move closer or further apart.

6. The intermittent thermal composite winding device according to claim 5, characterized in that, The first composite sheet and the second composite sheet have multiple thermally bonded regions, which are spaced apart. The thermally bonded regions are the areas on the wound cell other than the bending areas.

7. The intermittent thermal composite winding device according to claim 6, characterized in that, The dimensions of the first thermal bonding plate and the second thermal bonding plate are the same as the dimensions of the thermal bonding area.

8. The intermittent thermal composite winding device according to claim 3, characterized in that, Also includes: The first unwinding mechanism is used to output the positive electrode sheet; The second unwinding mechanism is used to output the first diaphragm, and the second unwinding mechanism operates synchronously with the first unwinding mechanism. The third unwinding mechanism is used to output the negative electrode sheet; The fourth unwinding mechanism is used to output the second diaphragm, and the fourth unwinding mechanism operates synchronously with the third unwinding mechanism.

9. A lithium battery, characterized in that, This includes wound cells as described in any one of claims 1-2 or wound cells obtained by using an intermittent thermal composite winding device as described in any one of claims 3-8.

10. A battery pack, characterized in that, Including the lithium battery as described in claim 9.

Images