Battery cells, battery packs, and electronic devices

Abstract

This invention provides battery cells, battery packs, and electronic devices that can improve the safety of batteries. [Solution] The present invention provides a battery cell, a battery pack, and an electronic device. The battery cell includes a case that includes an end wall and a side wall that surrounds the end wall, and a housing chamber formed by the end wall and the side wall, and a winding structure located inside the housing chamber and formed by stacking and winding a positive electrode piece, a separator, and a negative electrode piece, the winding structure includes an electrode assembly that is in the setting direction from the second end to the first end and a first insulating film that is provided so as to surround the outer circumference near the first end of the winding structure at least once, the first insulating film includes a setting step that extends beyond the outer end surface of the positive electrode tab in the setting direction, the setting step extends toward the end wall, and the range of possible values ​​of the angle between the extending direction of the setting step and the height direction is 0 to 60 degrees, thereby preventing the first insulating film from forming wrinkles that can store electrolyte, thereby improving the safety of the battery.

Description

Technical Field

[0001] The present invention relates to the field of battery cells, and particularly to battery cells, battery packs, and electronic devices.

Background Art

[0002] In recent years, with the rapid development of electric vehicles, consumer electronics, and new energy storage systems, in electric vehicles, battery technology is an important factor related to their development.

[0003] In the development of battery technology, the method of improving the safety of batteries is an urgent technical problem to be solved in battery technology.

Summary of the Invention

Problems to be Solved by the Invention

[0004] The technical problem to be solved by the present invention is to provide a battery cell, a battery pack, and an electronic device in order to overcome the above-mentioned technical problems of the prior art.

Means for Solving the Problems

[0005] The present invention solves the above-mentioned technical problems through the following technical solutions. A battery cell, including an end wall and a side wall provided so as to surround the end wall, and a case provided with an accommodation chamber formed by surrounding the end wall and the side wall, including a winding structure formed by laminating and winding a positive electrode plate, a separator, and a negative electrode plate, which is located in the accommodation chamber, the winding structure including a first end provided with a positive electrode tab and a second end provided with a negative electrode tab along the height direction, and an electrode assembly in a set direction from the second end to the first end, The first insulating film is provided so as to encircle at least one outer circumference of the winding structure near the first end, and along the setting direction, the first insulating film includes a setting step that extends beyond the outer end surface of the positive electrode tab, the setting step extends toward the end wall, and the range of possible values ​​for the angle between the extending direction of the setting step and the height direction is 0 to 60 degrees.

[0006] In this technical solution, by setting the range of possible values ​​for the angle between the stretching direction and the height direction of the setting stage of the first insulating film to 0 to 60 degrees, that is, by bonding and attaching the setting stage to the first current collector, which is electrically connected to the positive electrode tab along the radial direction of the electrode assembly without bending, wrinkles are formed that can store electrolyte, preventing the electrolyte in the wrinkles from penetrating into the case and causing corrosion of the case, thereby improving the safety of the battery.

[0007] Preferably, the battery cell further includes a first current collector, the first current collector is located between the positive electrode tab and the end wall of the case along the height direction, the first current collector includes interconnected pole connectors and positive electrode tab connectors, the positive electrode tab connector is electrically connected to the positive electrode tab, and the pole connector is electrically connected to the pole. The first insulating film comprises a substrate and an adhesive layer provided on a portion of the surface of the substrate, and along the setting direction, the substrate includes a first region beyond one side of the positive electrode tab connection that is away from the electrode assembly, the first region is not covered by the adhesive layer, and / or The battery cell further includes a first insulating seal component, the first insulating seal component being positioned between the first current collector and the end wall along the height direction, and along the setting direction, the edge of the first insulating film not extending beyond one side of the first insulating seal component away from the electrode assembly.

[0008] Preferably, along the setting direction, the substrate includes a second region covered by the adhesive layer and a third region not covered by the adhesive layer, wherein the third region includes the first region, or the third region overlaps with the first region. If W is the width of the substrate along the height direction, and w is the width of the second region along the height direction, then the range of possible values ​​for w / W is 0.12 to 0.8.

[0009] Preferably, the first insulating film is fixedly connected to the first insulating seal component.

[0010] Preferably, the positive electrode tab is a planar tab, and the positive electrode tab forms a planar surface along the height direction, and if d is the distance the first insulating film extends beyond the planar surface along the setting direction, and D is the distance from the inner surface of the end wall to the planar surface, then the range of possible values ​​for d / D is 0.1 to 0.99.

[0011] Preferably, the battery cell further includes a second insulating film, the second insulating film being provided so as to surround the outer circumference of the winding structure and located between the first end and the second end along the height direction, Along the radial direction of the winding structure, the orthographic projections of the first insulating film and the second insulating film do not overlap, and / or, The material of the substrate of the second insulating film is polyimide (PI) or polyethylene terephthalate (PET), and / or The ratio of the thickness of the second insulating film to the thickness of the first insulating film is 0.8 to 1.1, and / or The peel strength of the first insulating film is 2 to 7 times that of the second insulating film.

[0012] Preferably, the second insulating film is continuously installed along the circumferential direction of the winding structure and does not overlap, forming an uncovered region of the winding structure on the outer periphery of the winding structure that is not covered by the second insulating film, and the orthogonal projection of the overlapping portion of the first insulating film along the circumferential direction of the winding structure along the height direction is at least partially located in the uncovered region of the winding structure.

[0013] Preferably, the battery cell is a cylindrical battery, and the battery cell further comprises The pole includes a pole that penetrates the end wall and is electrically connected to the positive electrode tab through the first current collector, and has an injection hole along the height direction, and / or, An opening is provided at one end of the housing chamber of the case, away from the end wall, and the case further includes a crimped portion, the crimped portion is formed at one end of the side wall near the opening, and is recessed toward the interior of the case. The aforementioned battery cell further, A cover plate attached to the opening, A second insulating seal component is provided so as to surround the periphery of the cover plate and insulates and seals the cover plate and the case, The second current collector is installed between the electrode assembly and the cover plate, is electrically connected to the case, and the connecting piece of the second current collector is located on one side of the crimped portion facing the electrode assembly, and is welded to the crimped portion. and / or, The material of the substrate for the first insulating film is polyimide (PI).

[0014] A battery pack characterized by including the above-mentioned battery cells.

[0015] An electronic device characterized by including the aforementioned battery pack. [Effects of the Invention]

[0016] The positive advancements of this invention are as follows: The present invention sets the range of the possible values of the included angle between the stretching direction and the height direction of the setting step of the first insulating film to 0° to 60°, that is, by adhering and attaching it to the first current collector plate that is electrically connected to the positive electrode tab along the radial direction of the electrode assembly without bending the setting step, a wrinkle capable of storing an electrolytic solution is formed by adhering and attaching it to the first current collector plate, and it is possible to avoid the electrolytic solution in the wrinkle from penetrating into the case and causing corrosion of the case, thereby improving the safety of the battery.

[0017] The battery cell of the present invention further includes a pole post. The pole post is provided with a liquid injection hole along the height direction. The liquid injection hole is installed corresponding to the first end of the electrode assembly. The electrolytic solution flows into the case from the liquid injection hole. By setting a specific structure in which the range of the possible values of the included angle between the stretching direction and the height direction of the setting step of the first insulating film at the first end is 0° to 60°, it is possible to effectively avoid the electrolytic solution injected from the liquid injection hole from entering between the first insulating film and the case, thereby improving the electrolytic solution infiltration efficiency during positive electrode liquid injection.

Brief Description of the Drawings

[0018] [Figure 1] It is a schematic structural view of a battery cell according to an embodiment of the present invention. [Figure 2] It is a schematic cross-sectional structure view of a battery cell according to an embodiment of the present invention. [Figure 3] It is a partially enlarged schematic structural view of part A in FIG. 2. [Figure 4] It is a partially enlarged schematic structural view of part B in FIG. 2. [Figure 5] It is a schematic structural view of a part of another implementation method of a battery cell according to an embodiment of the present invention. [Figure 6] It is a schematic structural view of a part of yet another implementation method of a battery cell according to an embodiment of the present invention. [Figure 7] It is a schematic three-dimensional structure view of the electrode assembly of a battery cell according to a preferred embodiment of the present invention. [Figure 8] It is a schematic cross-sectional structure view of the electrode assembly of a battery cell according to a preferred embodiment of the present invention. [Figure 9] This is a schematic diagram of a partial structure of the first insulating film of a battery cell in one preferred embodiment of the present invention when it is unfolded. [Figure 10] This is a schematic diagram of the structure of a battery pack according to one preferred embodiment of the present invention. [Figure 11] This is a schematic diagram of the structure of an electronic device according to one preferred embodiment of the present invention. [Modes for carrying out the invention]

[0019] The present invention will be described more clearly and completely below, with reference to preferred embodiments and in conjunction with the accompanying drawings.

[0020] As shown in Figures 1 to 6, this embodiment provides a battery cell 1. The battery cell 1 includes a case 10, an electrode assembly 20, and a first insulating film 40.

[0021] The case 10 includes an end wall 11 and a side wall 12 that surrounds the end wall 11. A housing chamber 13 is formed by the end wall 11 and the side wall 12, and is used to house the electrode assembly 20, electrolyte, and other necessary battery components. The connection between the end wall 11 and the side wall 12 can be achieved by various methods, such as integral press molding, integral casting, or segmented welding.

[0022] As shown in Figures 7 and 8, the electrode assembly 20 is located within the housing chamber 13 and includes a winding structure 201 formed by stacking and winding a positive electrode piece 21, a separator 22, and a negative electrode piece 23. The winding structure 201 includes a first end with a positive electrode tab 211 and a second end with a negative electrode tab along the height direction H, and the direction from the second end to the first end is the setting direction Q.

[0023] The first insulating film 40 is provided so as to encircle at least one outer circumference near the first end of the wound structure 201, and along the setting direction Q, the first insulating film 40 includes a setting step 401 that extends beyond the outer end surface of the positive electrode tab 211, the setting step 401 extends toward the end wall 11, and the range of possible values ​​for the angle α between the extending direction of the setting step 401 and the height direction H is 0 to 60 degrees.

[0024] Thus, by setting the range of possible values ​​for the angle α between the stretching direction and the height direction H of the setting step 401 of the first insulating film 40 to 0 to 60 degrees, that is, by bonding and attaching the setting step to the first current collector 31 which is electrically connected to the positive electrode tab 211 along the radial direction R of the electrode assembly 20 without bending, wrinkles that can store electrolyte are formed when it is bonded and attached to the first current collector, preventing the electrolyte in the wrinkles from penetrating into the case 10 and causing corrosion of the case 10, thereby improving the safety of the battery. Furthermore, the first insulating film 40 includes a setting step 401 that extends beyond the outer surface of the positive electrode tab 211, and the case material of large cylindrical batteries (similar to cylindrical batteries such as 4680 / 4695 / 46120 / 46150) is steel, which can have higher strength, and since the steel case is often electrically connected to the negative electrode tab and carries a negative charge, the design of this embodiment can form electrical insulation between the positive electrode tab 211 and the case 10, increasing the safety of the battery. Here, the setting stage 401 extends beyond the outer end surface of the positive electrode tab 211 along the setting direction Q, where the outer end surface refers to the outer end surface (highest point) of the positive electrode tab 211 along the setting direction Q. Furthermore, the first insulating film includes a setting stage that extends beyond the outer surface of the positive electrode tab, and the case material of the large cylindrical battery (similar to cylindrical batteries such as 4680 / 4695 / 46120 / 46150) is steel, which can have higher strength, and the steel case is often electrically connected to the negative electrode tab and carries a negative charge, so the design of the present invention can form electrical insulation between the positive electrode tab and the case, increasing the safety of the battery.

[0025] One point that needs explanation is that the angle α between the extension direction of the setting stage 401 and the height direction H is an acute angle formed by the extension direction of the setting stage 401 and the height direction H, and the range of values ​​that this acute angle can take is 0 to 60 degrees. Referring again to Figure 4, in one embodiment of this embodiment, when the angle α between the extension direction of the setting stage 401 of the first insulating film 40 and the height direction H is 0 degrees, that is, the setting stage 401 is set along the height direction H. However, it is not limited to this, and referring again to Figure 5, in another embodiment of this embodiment, the arrangement of the first insulating film 40 or the arrangement of the battery causes a slight bend or inclination in the first insulating film 40 that extends along the height direction H, and as a result the angle α between the extension direction of the setting stage 401 of the first insulating film 40 and the height direction H becomes an angle of 10 degrees, 15 degrees, 30 degrees, 40 degrees, 55 degrees, or 60 degrees or less. Furthermore, the first insulating film 40 is provided so as to encircle at least one portion of the outer circumference near the first end of the winding structure 201, thereby forming an overlapping portion of the first insulating film 40 along the radial direction R along the circumferential direction P of the winding structure 201, and along the radial direction R of the winding structure 201, the first insulating film 40 is located between the electrode assembly 20 and the side wall 12 of the case 10.

[0026] Preferably, the angle α between the stretching direction and the height direction H of the setting stage 401 of the first insulating film 40 can take a range of 0 to 30 degrees. That is, the portion of the first insulating film 40 that extends beyond the outer surface of the positive electrode tab 211 is provided parallel or nearly parallel to the height direction H of the electrode assembly 20. When the first insulating film 40 is bonded to the first current collector 31, wrinkles that can store electrolyte are formed, which better avoids causing corrosion of the case. In addition, better electrical insulation can be formed between the positive electrode tab 211 and the case 10, increasing the safety of the battery.

[0027] Further explanation is needed when the setting stage 401 includes a multi-stage structure along the height direction H. The angle α formed by the extension direction of the setting stage 401 and the height direction H refers to the angle formed by the extension direction of the stage closest to the positive electrode tab 211 and the height direction H. Referring again to Figure 6, in yet another embodiment of this model, the setting stage 401 includes a first stage 4011 close to the positive electrode tab 211 and a second stage 4012 further away from the positive electrode tab 211. The angle α formed by the extension direction of the setting stage 401 and the height direction H refers to the angle formed by the extension direction of the first stage 4011 and the height direction H, and this angle is 0 degrees.

[0028] The battery cell 1 further includes the first current collector 31 described above, the first current collector 31 is located between the positive electrode tab 211 and the end wall 11 of the case 10 along the height direction H, and the first current collector 31 includes interconnected pole pole connectors 311 and positive electrode tab connectors 312, the positive electrode tab connector 312 is electrically connected to the positive electrode tab 211 and the pole pole connector 311 is electrically connected to the pole pole 70.

[0029] As shown in Figure 9, specifically, the first insulating film 40 includes a substrate 41 and an adhesive layer 42 provided on a portion of the surface of the substrate 41. Along the setting direction Q, the substrate 41 includes a first region 411 that extends beyond one side away from the electrode assembly 20 of the positive electrode tab connection portion 312 of the first current collector 31, and the first region 411 is not covered by the adhesive layer 42. The adhesive layer 42 covers a portion of the substrate 41 on one side toward the winding structure 201, fixing the first insulating film 40 to the outer circumference of the winding structure 201. By providing the first region 411 so as not to be covered by the adhesive layer 42, the range of possible values ​​for the angle α between the first region 411 and the height direction H can be brought closer to 0 degrees. By providing the adhesive layer 42, it is possible to avoid the first region 411 adhering to the first current collector 31 during the assembly process, which would form wrinkles on the surface of the first current collector 31 that can store electrolyte, thus preventing corrosion of the case.

[0030] Preferably, along the setting direction Q, the substrate 41 includes a second region 412 covered by the adhesive layer 42 and a third region 413 not covered by the adhesive layer 42, the third region 413 overlapping with the first region 411. However, it is not limited thereto, and in other embodiments, the third region 413 may include the first region 411, and this may be adjusted according to actual needs.

[0031] If we let W be the width of the base material 41 along the height direction H, and w be the width of the second region 412 along the height direction H, and both w and W are in mm, then the range of values ​​that w / W can take is 0.12 to 0.8, and may be, for example, 0.12, 0.3, 0.46, 0.75, or 0.8. By setting a range of values ​​that w / W can take, on the one hand, we can avoid a situation where the width of the second region 412 covered by the adhesive layer 42 becomes excessively small, preventing the first insulating film 40 from being fixed to the outer circumference of the electrode assembly 20, and on the other hand, we can avoid a situation where the width of the second region 412 becomes excessively large, making it prone to wrinkles, making it easy to store electrolyte, and causing corrosion of the case.

[0032] Specifically, the range of values ​​that w can take is 3mm to 6mm, for example, 3mm, 4mm, 4.5mm, 5.8mm, or 6mm. The range of values ​​that W can take is 7mm to 13mm, for example, 7mm, 8.5mm, 10mm, 11.8mm, or 13mm. By setting a range of values ​​that w can take, on the one hand, it is possible to avoid a situation where the width of the second region 412 covered by the adhesive layer 42 becomes excessively small, preventing it from effectively fixing the first insulating film 40 to the outer circumference of the electrode assembly 20, and on the other hand, it is possible to avoid a situation where the width of the second region 412 becomes excessively large, making it prone to wrinkles, accumulating electrolyte, and causing corrosion of the case. By setting a range of values ​​that W can take, on the one hand, it is possible to avoid a situation where the width of the base material 41 becomes excessively small, preventing it from effectively performing its insulating function, and on the other hand, it is possible to avoid a situation where the width of the base material 41 becomes excessively large, affecting the overall dimensions of the electrode assembly 20 and, consequently, the energy density of the battery.

[0033] The thickness of the substrate 41 is 40 μm to 65 μm, and may be, for example, 40 μm, 48 μm, 52.5 μm, 60.8 μm, or 65 μm. By setting a thickness range for the substrate 41, it is possible to avoid the difficulty in obtaining the necessary electrical insulation and support strength due to the substrate 41 being excessively thin, and at the same time, to avoid the increase in the overall structure thickness and the impact on the energy density of the battery due to the substrate 41 being excessively thick.

[0034] In this embodiment, the positive electrode tab 211 is a flattening tab, and the positive electrode tab 211 has a flattening surface along the height direction H. Along the setting direction Q, if d is the distance the first insulating film 40 exceeds the flattening surface, and D is the distance from the inner surface of the end wall 11 to the flattening surface, and both d and D are in mm, then the range of values ​​that d / D can take is 0.1 to 0.99, and may be, for example, 0.1, 0.3, 0.55, 0.8, or 0.99. By setting a range of values ​​that d / D can take, on the one hand, it is possible to avoid a situation where the distance the first insulating film 40 exceeds the flattening surface becomes excessively small, resulting in a failure to perform the insulating function, and on the other hand, it is possible to avoid a situation where the distance the first insulating film 40 exceeds the flattening surface becomes excessively large, resulting in unwanted wrinkles being generated due to contact with the case 10 when assembling the electrode assembly 20 and the case 10. Specifically, the distance d over which the first insulating film 40 extends beyond the planarization surface is 1 mm to 5 mm, and may be, for example, 1 mm, 2 mm, 2.5 mm, 3.8 mm, or 5 mm.

[0035] The battery cell 1 further includes a first insulating seal component 50, which is positioned between the first current collector 31 and the end wall 11 along the height direction H. By installing the first insulating seal component 50, contact between the first current collector 31 and the end wall 11 that would cause a short circuit is avoided. Along the setting direction Q, the edge of the first insulating film 40 does not extend beyond one side away from the electrode assembly 20 of the first insulating seal component 50, thereby preventing the first insulating film 40 and the end wall 11 from contacting each other and causing unwanted wrinkles, generating stress in the width direction of the first insulating film 40, and thus avoiding contact with the end wall 11 in situations where there are assembly errors. At the same time, the end wall 11 is generally welded to an external relay piece, and at this time, contact between the first insulating film 40 and the end wall 11 would make the first insulating film 40 susceptible to thermal effects, causing shrinkage and affecting the safety performance of the battery.

[0036] Preferably, the first insulating film 40 and the first insulating seal component 50 are fixedly connected to form an insulating structure connected to the outer circumference of the first end of the electrode assembly 20, thereby preventing the electrode assembly 20 from contacting the end wall 11 and side wall 12 of the case 10, achieving better insulation and improving safety under operating conditions such as battery vibration. Specifically, the first insulating film 40 and the first insulating seal component 50 can be fixedly connected by thermal fusion welding. Furthermore, the first insulating film 40 is provided so as to surround the outer circumference of the first insulating seal component 50 to form a closed ring structure, thereby forming an integral closed insulating structure on the outer circumference of the first end of the electrode assembly 20, further improving insulation and safety.

[0037] Furthermore, the battery cell 1 further includes a second insulating film 60, which is provided so as to surround the outer circumference of the winding structure 201 and is located between the first end and the second end along the height direction H. Along the radial direction R of the winding structure 201, the orthographic projections of the first insulating film 40 and the second insulating film 60 do not overlap, that is, along the height direction H of the winding structure 201, a portion of the position of the winding structure 201 covers the second insulating film 60, and the second insulating film 60 and the first insulating film 40 are offset from each other, thereby preventing the electrode assembly 20 from being stacked along the radial direction R and affecting the diameter of the electrode assembly 20, thereby improving the energy density, and the second insulating film 60 further serves to fix the outer separator 22, preventing the separator 22 from loosening.

[0038] Referring again to Figure 8, the positive electrode piece 21 includes a positive electrode piece start end 217 and a positive electrode piece end end 218, and the negative electrode piece 23 includes a negative electrode piece start end 237 and a negative electrode piece end end 238. The separator 22 includes a separator start end 221 and a separator end end 222. The second insulating film 60 is not limited to a termination tape for fixing the separator end end 222. That is, the second insulating film 60 may be a termination tape or another insulating structure, such as a Mylar film. Whatever the structure of the second insulating film 60 may be, it does not overlap with the orthographic projection of the first insulating film 40 along the radial R of its winding structure 201.

[0039] The ratio of the thickness of the second insulating film 60 to the first insulating film 40 is 0.8 to 1.1, and may be, for example, 0.8, 0.85, 0.95, 1.0, or 1.1. As described above, the setting stage 401 of the first insulating film 40 is provided parallel or nearly parallel to the height direction H of the electrode assembly 20. Compared to the setting stage 401 of the first insulating film 40 being attached to the first current collector 31, providing the first insulating film 40 by setting a range of possible values ​​for the ratio of the thickness of the second insulating film 60 to the first insulating film 40 allows the diameter of the electrode assembly 20 to be brought closer to matching, improving the energy density of the battery and allowing for more precise assembly.

[0040] Preferably, the substrate material of the first insulating film 40 is PI (Polyimide). The position where the first insulating film 40 is set is the first end of the electrode assembly 20, which is the output end of the positive electrode. Although relatively high temperatures are generated when welding to the first current collector 31, PI material has relatively high heat resistance. By setting the material of the first insulating film 40 to PI, its insulating function can be further improved due to its relatively high heat resistance. The adhesive layer of the first insulating film 40 contains polyacrylate.

[0041] The second insulating film 60 includes a substrate and an adhesive layer provided on a portion of the substrate's surface. The substrate material of the second insulating film 60 is PI (Polyimide) or PET (Polyethylene terephthalate). As described above, the main function of the second insulating film 60 is to fix the separator end portion 222. Preferably, the material of the second insulating film 60 is PET, which allows it to fix the separator end portion 222 while simultaneously achieving the beneficial technical effect of saving manufacturing costs. The adhesive layer of the second insulating film 60 contains polyacrylate.

[0042] The peel strength of the first insulating film 40 is 2 to 7 times that of the second insulating film 60, for example, 2 times, 3.5 times, 4.5 times, 5.8 times, or 7 times, that is, the peel strength of the first insulating film 40 is greater than that of the second insulating film 60. Since the winding structure 201 expands and contracts during the charge and discharge process, if the adhesive force of the second insulating film 60 is too high, it will suppress the expansion of the winding structure 201, which is unfavorable for achieving the battery cell capacity. On the other hand, if the adhesive force of the second insulating film 60 is too low, it will not be able to fix the winding structure 201, and the winding structure 201 will loosen. The first insulating film 40 needs to fix the winding structure 201 and the positive electrode tab 211 simultaneously, and therefore a greater adhesive force is required to ensure that the winding structure 201 and the positive electrode tab 211 do not loosen and to be advantageous for inserting the first end of the winding structure 201 into the case. Furthermore, if the adhesive strength of the first insulating film 40 is low and it detaches, it can cause insulation failure, and there is a risk that the positive electrode tab 211 will come into contact with the case 10 and cause a short circuit. Therefore, by setting the peel strength of the first insulating film 40 to 2 to 7 times that of the peel strength of the second insulating film 60, it is possible to ensure that the normal performance of the battery cell capacity can be guaranteed. Specifically, the peel strength of the first insulating film 40 is 2 N / cm to 7 N / cm, and the peel strength of the second insulating film 60 is 1 N / cm to 4 N / cm.

[0043] Preferably, the second insulating film 60 is continuously installed along the circumferential direction P of the winding structure 201 without overlapping, forming an uncovered region of the winding structure 201 on its outer circumference that is not covered by the second insulating film 60, and the orthogonal projection of the overlapping portion of the winding structure 201 along the circumferential direction P of the first insulating film 40 along the height direction H is located at least partially in the uncovered region of the winding structure 201. By positioning the orthogonal projection of the overlapping portion of the winding structure 201 along the circumferential direction P of the first insulating film 40 along the height direction H of the winding structure 201 at least partially in the uncovered region of the winding structure 201, the overlapping portion of the winding structure 201 along the circumferential direction P of the first insulating film 40 overlaps with the second insulating film 60 in the radial direction R, thereby avoiding an effect on the diameter of the battery cell and improving energy density. Furthermore, the first insulating film 40 provides support to the uncovered region of the winding structure 201, preventing a large difference in stress between the uncovered region of the winding structure 201 and the covered region of the winding structure 201 covered by the second insulating film 60 during battery use, thereby preventing lithium deposition after battery expansion.

[0044] Preferably, the second insulating film 60 and the first insulating film 40 are integrated into a single structure, which improves production efficiency and reduces the diameter of the battery cell, thereby ensuring the energy density of the battery.

[0045] In this embodiment, the battery cell 1 is a cylindrical battery. Cylindrical batteries have advantages such as high energy density, long cycle life, and good safety performance. Furthermore, when the battery cell 1 is a cylindrical battery, the case 10 of the cylindrical battery is a steel case, so the case 10 is negatively charged, and the first insulating film 40 includes a setting stage 401 that extends beyond the outer surface of the positive electrode tab 211, and the range of values ​​that the angle α between the extension direction and the height direction H of the setting stage 401 can take is 0 to 60 degrees, thereby enabling insulation between the positive electrode tab 211 and the case 10, and since the cylindrical battery has an all-pole tab design, the first insulating film is provided so as to surround at least one outer circumference near the first end of the winding structure 201. However, it is not limited to this, and in other embodiments, the battery cell 1 may be a battery of other shapes such as a prismatic battery.

[0046] In this embodiment, by applying a specific structure to a cylindrical battery in which the angle α between the extension direction and the height direction H of the portion of the first insulating film 40 that extends beyond the outer surface of the positive electrode tab 211 (setting stage 401) can take place between 0 and 60 degrees, the first insulating film 40 is bonded and attached to the first current collector 31, forming wrinkles that can store electrolyte. This prevents the electrolyte in the wrinkles from penetrating into the case 10 and causing corrosion of the case 10, thereby improving the safety of the battery. Furthermore, the first insulating film 40 includes a setting stage 401 that extends beyond the outer surface of the positive electrode tab 211, and the case material of large cylindrical batteries (similar to cylindrical batteries such as 4680 / 4695 / 46120 / 46150) is steel, which can have higher strength. Since steel cases are often electrically connected to the negative electrode tab and become negatively charged, the design of this embodiment can form electrical insulation between the positive electrode tab 211 and the case 10, increasing the safety of the battery.

[0047] The battery cell 1 further includes an electrode column that penetrates the end wall 11 and is electrically connected to the positive electrode tab 211 through the first current collector panel 31. An electrolyte injection hole 71 is provided in the electrode column 70 along the height direction H. The electrolyte injection hole 71 is set corresponding to the first end of the electrode assembly 20, and the electrolyte flows into the case 10 from the electrolyte injection hole 71. By setting a specific structure at the first end such that the angle α between the extension direction of the setting stage 401 of the first insulating film 40 and the height direction H can take a range of 0 to 60 degrees, the electrolyte injected from the electrolyte injection hole 71 can be effectively prevented from entering between the first insulating film 40 and the case 10, thereby improving the electrolyte infiltration efficiency during positive electrode injection.

[0048] An opening 14 is provided at one end of the housing chamber 13 of the case 10, away from the end wall 11. The case 10 further includes a crimped portion 15, which is formed at one end of the side wall 12 near the opening 14 and recessed toward the interior of the case 10. The battery cell 1 further includes a cover plate 80, a second insulating seal component 90, and a second current collector 32. The cover plate 80 is attached to the opening 14. The second insulating seal component 90 is provided so as to surround the periphery of the cover plate 80, insulating and sealing the cover plate 80 from the case 10. The second current collector 32 is positioned between the electrode assembly 20 and the cover plate 80 and is electrically connected to the case 10. The connecting piece of the second current collector 32 is located on one side of the crimped portion 15 facing the electrode assembly 20 and is welded to the crimped portion 15. In this way, by positioning the connecting piece of the second current collector 32 on one side of the crimping portion 15 facing the electrode assembly 20, and welding it to the crimping portion 15, that is, by positioning the welding area between the second current collector 32 and the tab closer to the electrode assembly 20 compared to the crimping portion 15, it is possible to prevent the crimping portion 15 from affecting the welding area between the tab and the second current collector 32, thereby improving the welding strength between the tab and the second current collector 32.

[0049] In this embodiment, the sequence in which the first current collector plate 31 and the second current collector plate 32 of the battery cell 1 are welded to the electrode assembly 20 is as follows: First, the first current collector plate 31 is placed. Next, the electrode assembly 20 is press-welded together on both the positive and negative electrodes (the press-welding process increases contact between the current collector plate and the electrode assembly 20, thus avoiding welding defects). The first current collector plate 31 is welded using linear welding, not spot welding. This is because the negative electrode tab is relatively soft, and after two press-welding processes, the distance between the second current collector plate 32 and the electrode assembly 20 becomes relatively close. Using spot welding would concentrate the heat, causing burns to the separator 22. However, using linear welding generates less heat, avoiding short circuits between the positive and negative electrodes caused by burns to the separator 22. Subsequently, the second current collector plate 32 is placed again. The electrode assembly 20 is again press-welded together on both the positive and negative electrodes. Finally, the second current collector plate 32 is welded.

[0050] As shown in Figure 10, the present invention further provides a battery pack 100 which includes the battery cell 1 described above. In one embodiment of the battery pack 100 of the present invention, the battery pack 100 includes a casing 310, a lid 320, and a plurality of battery cells 1, the plurality of battery cells 1 arranged in the casing 310 and connected to each other in series, parallel, or a combination of series and parallel, and the lid 320 is sealed over the casing 310 to provide protection for the plurality of battery cells 1. It should be noted that the battery pack 100 may include parts other than the battery cell 1 of the present invention, such as a battery pack 100 thermal management system and a circuit board, and the battery pack 100 may be a battery module, a battery pack, or a power storage cabinet. These will not be explained in detail here.

[0051] As shown in Figure 11, the present invention further provides an electronic device 1000, which includes the battery pack 100 described above. The actuation unit 300 is electrically connected to the battery pack 100 to obtain power support. As an example, the electronic device 1000 is a vehicle, which may be a fuel-powered vehicle, a gas vehicle, or a new energy vehicle, and the new energy vehicle may be, but is not limited to, a battery-powered electric vehicle, a hybrid vehicle, or a range-extender vehicle. The actuation unit 300 is the vehicle body, and the battery pack 100 is installed at the bottom of the vehicle body to provide power support for the vehicle's operation or the operation of in-vehicle electrical components. However, in some other embodiments, the electronic device 1000 may further be a mobile phone, a portable device, a laptop computer, a ship, a spacecraft, an electric toy, and a power tool, etc. Spacecraft include airplanes, rockets, space shuttles, and spacecraft, etc. The actuation unit 300 may be a unit component that can obtain power from the battery pack 100 and performs a corresponding operation, such as a fan blade rotation unit or a vacuum cleaner suction operation unit. Electric toys include stationary or mobile electric toys, such as game consoles, electric car toys, electric boat toys, and electric aircraft toys. Power tools include metal cutting power tools, polishing power tools, assembly power tools, and railway power tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact electric drills, concrete vibrators, and electric planers. The embodiments of this application do not impose any special limitations on the electronic devices 1000 described above.

[0052] Although specific embodiments of the present invention have been described above, those skilled in the art should understand that this is merely illustrative and that the scope of protection of the present invention is limited by the appended claims. Those skilled in the art can make numerous changes or modifications to these embodiments without departing from the principles and substance of the present invention, and all such changes and modifications fall within the scope of protection of the present invention. [Industrial applicability]

[0053] The battery cell, battery pack, and electronic device of this application can be applied in the field of battery technology. [Explanation of Symbols]

[0054] 1000:Electronic equipment 100: Battery pack 300: Operating part 310: Box body 320: Lid 1: Battery cell 10: Case 11: End wall 12: Side wall 13: Confinement Room 14:Aperture 15: Crimping section 20: Electrode Assembly 201: Winding structure 21: Positive electrode piece 211: Positive Tab 217: Positive electrode start end 218: Positive electrode terminal 22: Separator 221: Separator start end 222: Separator end 23: Negative electrode piece 237: Starting end of negative electrode 238: Negative electrode terminal 31: First current collection panel 311: Pole pole connection section 312: Positive tab connection 32: Second current collection panel 40: First insulating film 401: Setting Stage 4011:First stage 4012:Second stage 41: Base material 411:First area 412:Second area 413:Third Realm 42: Adhesive layer 50: First insulating seal component 60: Second insulating film 70: Polar pillar 71: Liquid injection hole 80: Cover plate 90: Second insulating seal component H: Height direction of the winding structure R: Radial direction of the winding structure P: Circumferential direction of the wound structure Q: Setting direction

Claims

1. A case is provided which includes an end wall and a side wall provided so as to surround the end wall, and which has a storage chamber formed by being surrounded by the end wall and the side wall, Located within the aforementioned containment chamber, the winding structure includes a winding structure formed by stacking and winding a positive electrode piece, a separator, and a negative electrode piece, the winding structure includes a first end with a positive electrode tab and a second end with a negative electrode tab along the height direction, and the electrode assembly from the second end to the first end is in the setting direction, A first insulating film is provided so as to encircle at least one outer circumference of the winding structure near the first end, and along the setting direction, the first insulating film includes a setting step that extends beyond the outer end surface of the positive electrode tab, the setting step extends toward the end wall, and the range of possible values ​​for the angle between the extending direction of the setting step and the height direction is 0 to 60 degrees. A battery cell characterized by the following features.

2. The battery cell further includes a first current collector, the first current collector is located between the positive electrode tab and the end wall of the case along the height direction, the first current collector includes interconnected pole connectors and positive electrode tab connectors, the positive electrode tab connector is electrically connected to the positive electrode tab, and the pole connector is electrically connected to the pole. The first insulating film comprises a substrate and an adhesive layer provided on a portion of the surface of the substrate, and along the setting direction, the substrate includes a first region beyond one side of the positive electrode tab connection that is away from the electrode assembly, the first region is not covered by the adhesive layer, and / or The battery cell according to claim 1, further comprising a first insulating seal component, wherein the first insulating seal component is located between the first current collector and the end wall along the height direction, and the edge of the first insulating film does not extend beyond one side of the first insulating seal component away from the electrode assembly along the setting direction.

3. Along the setting direction, the substrate includes a second region covered by the adhesive layer and a third region not covered by the adhesive layer, wherein the third region includes the first region, or the third region overlaps with the first region. The battery cell according to claim 2, characterized in that, if W is the width of the base material along the height direction, and w is the width of the second region along the height direction, and the units of w and W are both mm, then the range of values ​​that w / W can take is 0.12 to 0.

8.

4. The battery cell according to claim 2, characterized in that the first insulating film is fixedly connected to the first insulating seal component.

5. The battery cell according to claim 1, characterized in that the positive electrode tab is a planar tab, the positive electrode tab forms a planar surface along the height direction, and along the setting direction, the distance at which the first insulating film extends beyond the planar surface is d, and the distance from the inner surface of the end wall to the planar surface is D, and the units of d and D are both mm, then the range of possible values ​​for d / D is 0.1 to 0.

99.

6. The battery cell further includes a second insulating film, the second insulating film is provided so as to surround the outer circumference of the winding structure and is located between the first end and the second end along the height direction. Along the radial direction of the winding structure, the orthographic projections of the first insulating film and the second insulating film do not overlap, and / or, The material of the substrate of the second insulating film is polyimide or polyethylene terephthalate, and / or The ratio of the thickness of the second insulating film to the thickness of the first insulating film is 0.8 to 1.1, and / or The battery cell according to claim 1, characterized in that the peel strength of the first insulating film is 2 to 7 times that of the second insulating film.

7. The battery cell according to claim 6, characterized in that the second insulating film is continuously installed along the circumferential direction of the winding structure and does not overlap, forming an uncovered region of the winding structure on the outer circumference of the winding structure that is not covered by the second insulating film, and the orthographic projection of the overlapping portion of the first insulating film along the circumferential direction of the winding structure along the height direction is at least partially located in the uncovered region of the winding structure.

8. The aforementioned battery cell is a cylindrical battery, The aforementioned battery cell further, The pole includes a pole that penetrates the end wall and is electrically connected to the positive electrode tab through the first current collector, and has an injection hole opened along the height direction, and / or, An opening is provided at one end of the housing chamber of the case, away from the end wall, and the case further includes a crimped portion, the crimped portion is formed at one end of the side wall near the opening, and is recessed toward the interior of the case. The aforementioned battery cell further, A cover plate installed in the opening, A second insulating seal component is provided so as to surround the periphery of the cover plate and insulates and seals the cover plate and the case, The second current collector is set between the electrode assembly and the cover plate, electrically connected to the case, and the connecting piece of the second current collector is located on one side of the crimped portion facing the electrode assembly, and is welded to the crimped portion, and / or The material of the substrate for the first insulating film is polyimide. The battery cell according to claim 1, characterized in that the material of the case is steel.

9. A battery pack characterized by including a battery cell according to any one of claims 1 to 8.

10. An electronic device characterized by including the battery pack described in claim 9.

Images