Winding electrode core and battery, battery assembly and electric device having the same

Abstract

This utility model discloses a wound electrode core and a battery, battery assembly, and electrical device having the same. The wound electrode core includes: a positive electrode sheet and a negative electrode sheet. The negative electrode sheet has a negative electrode head located inside the wound electrode core, and at least a portion of the negative electrode head is directly opposite to a portion of the positive electrode sheet facing the central axis of the wound electrode core. A separator assembly is used to separate the positive electrode sheet and the negative electrode sheet, and the separator assembly wraps around the negative electrode head. The separator assembly has multiple overlapping portions. According to the embodiments of this utility model, by making the separator assembly have multiple overlapping portions, when the separator assembly is heated and shrinks, the overlapping portions can reserve material for the shrinkage of the separator assembly, thereby improving the reliability of the separator assembly in separating the positive electrode sheet and the negative electrode sheet, and separating the negative electrode head and the positive electrode sheet. This facilitates reducing the risk of short circuits in the wound electrode core and reduces the possibility of metal accumulation at the negative electrode head.

Description

Technical Field

[0001] This utility model relates to the field of battery technology, and more specifically, to a wound electrode core and a battery, battery assembly and electrical device having the same. Background Technology

[0002] In related technologies, the wound electrode core generates heat during operation. The diaphragm in the wound electrode core will shrink when heated. If the diaphragm shrinks too much, it can easily cause the positive and negative electrode plates to come into contact, resulting in a short circuit safety risk in the wound electrode core. Utility Model Content

[0003] This invention aims to solve at least one of the technical problems existing in the prior art. To this end, this invention proposes a wound electrode core, which, by giving the diaphragm assembly multiple overlapping portions, allows material to be reserved for the shrinkage of the diaphragm assembly when it is heated. This improves the reliability of the diaphragm assembly in separating the positive and negative electrode plates, and separating the negative electrode head from the positive electrode plate, thereby reducing the risk of short circuits in the wound electrode core and reducing the possibility of metal accumulation at the negative electrode head.

[0004] This invention also proposes a battery having the aforementioned wound electrode core.

[0005] This utility model also proposes a battery assembly having the aforementioned battery.

[0006] This utility model also proposes an electrical device having the aforementioned battery or battery assembly.

[0007] A wound electrode core according to a first aspect of the present invention includes: a positive electrode sheet and a negative electrode sheet, the negative electrode sheet having a negative electrode head located inside the wound electrode core, at least a portion of the negative electrode head being disposed opposite to a portion of the positive electrode sheet facing the central axis of the wound electrode core; and a diaphragm assembly for separating the positive electrode sheet and the negative electrode sheet, the diaphragm assembly wrapping the negative electrode head, wherein the diaphragm assembly has multiple overlapping portions.

[0008] According to the embodiments of the present invention, the wound electrode core has multiple overlapping portions in the diaphragm assembly. When the diaphragm assembly is heated and shrinks, the overlapping portions can reserve material for the shrinkage of the diaphragm assembly, thereby improving the reliability of the diaphragm assembly in separating the positive electrode and the negative electrode, and separating the negative electrode head and the positive electrode. This facilitates reducing the risk of short circuits in the wound electrode core and reduces the possibility of metal accumulation at the negative electrode head.

[0009] In addition, the wound pole core according to the above embodiments of the present invention may also have the following additional technical features:

[0010] According to some embodiments of the present invention, the overlapping portion is located on one side of the thickness direction of the negative electrode head; and / or, at least a portion of the overlapping portion is directly opposite the negative electrode head in the thickness direction of the negative electrode head.

[0011] According to some embodiments of the present invention, the positive electrode sheet has a positive electrode head located inside the wound electrode core, the positive electrode head and the negative electrode head are arranged opposite to each other in the thickness direction of the negative electrode head, wherein, in the thickness direction of the negative electrode head, the overlapping portion is located on the side of the negative electrode head facing the positive electrode head; or, the overlapping portion is located on the side of the negative electrode head away from the positive electrode head.

[0012] According to some embodiments of the present invention, in the winding direction of the wound pole core, the length of the overlapping portion is 1mm to 5mm.

[0013] According to some embodiments of the present invention, the diaphragm assembly includes two diaphragms, which are respectively located on both sides of the negative electrode sheet in the thickness direction. The diaphragms have diaphragm heads located inside the wound electrode core. The diaphragm heads of the two diaphragms are at least partially connected and overlap to define the overlapping portion.

[0014] According to some optional embodiments of the present invention, the overlapping portion is located on one side of the thickness direction of the negative electrode head, a portion of the overlapping portion extends along the winding direction of the wound electrode core, and another portion is bent in the direction away from the negative electrode head, or another portion is bent in the direction close to the negative electrode head.

[0015] According to some embodiments of the present invention, a portion of the positive electrode sheet facing the central axis of the wound electrode core is provided with an inactive material layer, and at least a portion of the negative electrode head is disposed opposite to the inactive material layer.

[0016] According to some optional embodiments of the present invention, in the winding direction of the wound electrode core, the inactive material layer extends to be directly opposite at least one side in the thickness direction of the negative electrode head.

[0017] According to some specific embodiments of the present invention, in the winding direction of the wound electrode core, the inactive material layer is disposed around the negative electrode head, such that the negative electrode head is disposed opposite to the inactive material layer on both sides of the negative electrode head in the thickness direction.

[0018] According to some specific embodiments of this utility model, in the winding direction of the wound electrode core, the distance between the end of the inactive material layer that is directly opposite to the thickness direction of the negative electrode head and the negative electrode head is greater than 2mm.

[0019] According to some optional embodiments of the present invention, in the height direction of the wound electrode core, the height of the inactive material layer is not lower than the height of the negative electrode head.

[0020] According to some optional embodiments of the present invention, the positive electrode sheet includes a current collector, the current collector includes a coating area and a cleaning area, the coating area has a positive active material layer, and the inactive material layer is a coating material disposed in the cleaning area.

[0021] According to some embodiments of the present invention, the negative electrode sheet has a negative electrode tail located outside the wound electrode core. In the winding direction of the wound electrode core, the positive electrode sheet has an outer region and an inner region extending beyond the negative electrode tail. The inner region is located on the side of the outer region facing the central axis of the wound electrode core. At least one of the sides of the outer region and the inner region facing each other is provided with an insulating protective portion.

[0022] According to some embodiments of the present invention, the positive electrode sheet has a positive electrode head located inside the wound electrode core. In the winding direction of the wound electrode core, the positive electrode sheet includes a positive electrode corner portion located inside the wound electrode core, and the negative electrode sheet includes a negative electrode corner portion located inside the wound electrode core. The positive electrode head and the negative electrode corner portion are arranged facing each other.

[0023] According to a second aspect of the present invention, a battery is provided, the battery comprising: a housing having a receiving cavity; and a wound electrode core, wherein the wound electrode core is the wound electrode core described in the first aspect of the present invention, and the wound electrode core is disposed in the receiving cavity.

[0024] According to the battery of the present invention, by having the separator assembly have multiple overlapping portions, when the separator assembly is heated and shrinks, the overlapping portions can reserve material for the shrinkage of the separator assembly, thereby improving the reliability of the separator assembly in separating the positive electrode and the negative electrode, and separating the negative electrode head and the positive electrode, which helps to reduce the risk of short circuit in the wound electrode core and reduces the possibility of metal accumulation at the negative electrode head.

[0025] A battery assembly is provided according to a third aspect of the present invention, the battery assembly including the battery and circuit structure described in the second aspect of the present invention, the battery and the circuit structure being electrically connected.

[0026] According to the battery assembly of the present invention, by having the separator assembly have multiple overlapping portions, when the separator assembly is heated and shrinks, the overlapping portions can reserve material for the shrinkage of the separator assembly, thereby improving the reliability of the separator assembly in separating the positive electrode and the negative electrode, and separating the negative electrode head and the positive electrode, which helps to reduce the risk of short circuit in the wound electrode core and reduces the possibility of metal accumulation at the negative electrode head.

[0027] According to a fourth aspect of the present invention, an electrical device is provided, the electrical device comprising the battery described in the second aspect of the present invention or comprising the battery assembly described in the third aspect of the present invention.

[0028] According to the battery assembly of the present invention, by having the separator assembly have multiple overlapping portions, when the separator assembly is heated and shrinks, the overlapping portions can reserve material for the shrinkage of the separator assembly, thereby improving the reliability of the separator assembly in separating the positive electrode and the negative electrode, and separating the negative electrode head and the positive electrode, which helps to reduce the risk of short circuit in the wound electrode core and reduces the possibility of metal accumulation at the negative electrode head.

[0029] Additional aspects and advantages of this invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0030] The above and / or additional aspects and advantages of this utility model will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0031] Figure 1 This is a schematic diagram of the structure of the wound pole core according to an embodiment of the present utility model;

[0032] Figure 2 yes Figure 1 Enlarged view of point A in the middle;

[0033] Figure 3 yes Figure 1 Enlarged view of point B in the middle;

[0034] Figure 4 This is a schematic diagram of the structure of the positive electrode and the negative electrode according to an embodiment of the present invention;

[0035] Figure 5 This is a schematic diagram of the structure of the positive electrode sheet in the present invention when no non-active material layer is coated on it;

[0036] Figure 6 This is a schematic diagram of the structure of the positive electrode sheet coated with an inactive material layer according to an embodiment of this utility model;

[0037] Figure 7This is a schematic diagram of the structure of the positive electrode sheet with an insulating protective part according to an embodiment of the present invention;

[0038] Figure 8 This is a schematic diagram of the structure of the wound pole core according to an embodiment of the present utility model;

[0039] Figure 9 This is an enlarged view of a portion of the wound electrode core according to an embodiment of the present invention. At this time, the overlapping portion is located on the side of the negative electrode head facing the positive electrode head, and the other part of the overlapping portion is bent in the direction away from the diaphragm head.

[0040] Figure 10 This is an enlarged view of a portion of the wound electrode core according to an embodiment of the present invention. At this time, the overlapping portion is located on the side of the negative electrode head facing the positive electrode head, and the other part of the overlapping portion is bent towards the side closer to the diaphragm head.

[0041] Figure 11 This is an enlarged view of a portion of the wound electrode core according to an embodiment of the present invention, where the overlapping portion is located on the side of the negative electrode head facing away from the positive electrode head;

[0042] Figure 12 This is an enlarged view of a portion of the wound electrode core according to an embodiment of the present invention. At this time, the overlapping portion is located on the side of the negative electrode head facing away from the positive electrode head, and the other part of the overlapping portion is bent in the direction facing away from the diaphragm head.

[0043] Figure 13 This is an enlarged view of a portion of the wound electrode core according to an embodiment of the present invention. At this time, the overlapping portion is located on the side of the negative electrode head facing away from the positive electrode head, and the other part of the overlapping portion is bent towards the side closer to the diaphragm head.

[0044] Attached reference numerals: 1. Winded pole core;

[0045] 10. Positive electrode plate; 11. External region; 12. Internal region; 13. First connection region; 14. Second connection region; 15. Empty foil region; 161. Positive electrode head; 162. Positive electrode tail; 17. Cleaning region; 18. Positive electrode corner; 19. Positive electrode tab;

[0046] 20. Negative electrode plate; 21. Negative electrode head; 22. Negative electrode tail; 28. Negative electrode corner; 29. ​​Negative electrode tab;

[0047] 30. Insulation protection section;

[0048] 41. Inactive material layer; 42. Positive electrode active material layer; 43. Negative electrode active material layer;

[0049] 5. Diaphragm assembly; 501. Overlapping portion; 5011. First portion; 5012. Second portion; 50. Diaphragm; 51. Diaphragm head; 55. Adhesive portion. Detailed Implementation

[0050] The embodiments of this utility model are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this utility model, and should not be construed as limiting this utility model.

[0051] The wound pole core 1 according to an embodiment of the present invention is described below with reference to the accompanying drawings.

[0052] like Figures 1-4 As shown, the wound electrode core 1 according to an embodiment of the present invention includes a positive electrode sheet 10, a negative electrode sheet 20, and a diaphragm assembly 5.

[0053] The negative electrode 20 has a negative electrode head 21 located inside the wound electrode core 1. At least a portion of the negative electrode head 21 is disposed opposite to the portion of the positive electrode 10 facing the central axis of the wound electrode core. The diaphragm assembly 5 is used to separate the positive electrode 10 and the negative electrode 20 to separate the sides of the negative electrode 20 and the positive electrode 10 facing each other, so as to avoid direct contact between the positive electrode 10 and the negative electrode 20 and prevent short circuit inside the wound electrode core 1.

[0054] The separator assembly 5 encloses the negative electrode head 21. Specifically, the positive electrode 10 is coated with a positive electrode active material layer 42 on its side surface in the thickness direction, and the negative electrode 20 is coated with a negative electrode active material layer 43 on its side surface in the thickness direction. However, the end face of the negative electrode head 21 of the negative electrode 20 is not coated with the negative electrode active material layer 43.

[0055] Therefore, when positive ions move in the wound electrode core 1, positive ions in the positive electrode active material layer 42 that is closer to the negative electrode head 21 may reach the end face of the negative electrode head 21 and be deposited at the end face of the negative electrode head 21, forming a metal accumulation at the negative electrode head 21.

[0056] In other words, when positive ions reach the negative electrode head 21 where no negative electrode active material is coated, on the one hand, the positive ions cannot continue to move, affecting the capacity of the wound electrode core 1; on the other hand, when the metal at the negative electrode head 21 accumulates to a certain length, the accumulated metal will directly connect the positive electrode 10 and the negative electrode 20, causing an internal short circuit in the wound electrode core 1.

[0057] Therefore, by wrapping the negative electrode head 21 with the separator assembly 5, when the positive electrode 10, the negative electrode 20 and the separator assembly 5 are wound together to form the wound electrode core 1, the negative electrode head 21 and the positive electrode 10 can be separated by the separator assembly 5, reducing the possibility that positive ions at the positive electrode 10 will accumulate at the negative electrode head 21.

[0058] In addition, burrs are easily formed at both ends of the negative electrode 20 after cutting. If the burrs come into contact with the positive electrode 10 or the positive active material layer 42 on the positive electrode 10, it will cause a short circuit failure in the wound electrode core 1. The separator assembly 5 can wrap the negative electrode head 21 and can also use the separator assembly 5 to separate the negative electrode head 21 and the positive electrode 10, reducing the possibility that the metal burrs at the negative electrode head 21 will come into contact with the positive electrode 10, thereby improving the yield of the wound electrode core 1 and improving the stability of the operation of the wound electrode core 1.

[0059] The separator assembly 5 has multiple overlapping portions 501. During charging and discharging of the wound electrode core 1, the wound electrode core 1 generates heat, causing the separator assembly 5 to shrink. The overlapping portions 501 on the separator assembly 5 allow the overlapping portions 501 to extend when the separator assembly 5 shrinks, thus compensating for the shrinkage. This ensures the reliability of the separator assembly 5 in separating the positive electrode 10 and the negative electrode 20, improves the reliability of the separator assembly 5 in wrapping the negative electrode head 21, prevents leakage of the negative electrode head 21, and reduces the risk of metal accumulation at the negative electrode head 21 and the possibility of metal burrs at the negative electrode head 21 contacting the positive electrode 10.

[0060] It should be explained here that the overlapping part 501 can be two layers of overlap, three layers of overlap, or more layers of overlap; there are no further restrictions here.

[0061] In some embodiments, a portion of the diaphragm assembly 5 is adapted to be bent to define an overlapping portion 501. Specifically, multiple overlapping portions of the diaphragm assembly 5 may be bent and then overlapped again to define the overlapping portion 501. No further restrictions are imposed here.

[0062] Therefore, according to the embodiment of the present invention, the wound electrode core 1, by having the diaphragm assembly 5 with multiple overlapping portions 501, can reserve material for the shrinkage of the diaphragm assembly 5 when the diaphragm assembly 5 is heated and shrunk, thereby improving the reliability of the diaphragm assembly 5 in separating the positive electrode 10 and the negative electrode 20, and separating the negative electrode head 21 and the positive electrode 10, which helps to reduce the risk of short circuit of the wound electrode core 1 and reduce the possibility of metal accumulation at the negative electrode head 21.

[0063] The wound pole core 1 according to a specific embodiment of the present invention is described below with reference to the accompanying drawings.

[0064] In some specific embodiments of this utility model, such as Figures 1-4 As shown, the wound electrode core 1 includes a positive electrode 10, a negative electrode 20, and a separator assembly 5.

[0065] In some embodiments of this utility model, the overlapping portion 501 is located on one side of the negative electrode head 21 in the thickness direction.

[0066] Specifically, the side of the diaphragm assembly 5 in the thickness direction of the negative electrode head 21 has a larger area, and the overlapping part 501 is located on one side in the thickness direction of the negative electrode head 21 to facilitate the design of a larger area for the overlapping part 501.

[0067] The diaphragm assembly 5 shrinks significantly along its length when heated, meaning the area covered by the diaphragm assembly 5 covering the negative electrode 20 decreases when it shrinks. The overlapping portion 501 is positioned on one side of the negative electrode head 21 in the thickness direction. This increases the area of ​​the diaphragm assembly 5 covering the surface of the negative electrode 20 in the thickness direction after the diaphragm assembly 5 expands upon heating and shrinking. This ensures the diaphragm assembly 5 effectively isolates the negative electrode 20 and the positive electrode 10, preventing direct contact between them and thus avoiding short circuits inside the wound electrode core 1.

[0068] Furthermore, placing the overlapping portion 501 on one side of the negative electrode head 21 in the thickness direction facilitates the winding of the positive electrode 10, the negative electrode 20, and the separator assembly 5 together to form the wound electrode core 1.

[0069] It needs to be explained here that after the positive electrode 10, negative electrode 20, and separator assembly 5 are wound, the thickness directions of the positive electrode 10, negative electrode 20, and separator assembly 5 are different at different positions. However, the thickness direction of the negative electrode head 21 refers to the thickness direction of the negative electrode 20 at that position, meaning the thickness direction of the negative electrode head 21 is constant. Specifically, before or after the positive electrode 10, negative electrode 20, and separator assembly 5 are wound, the surfaces of the positive electrode 10, negative electrode 20, and separator assembly 5 on one side of the thickness direction are the same.

[0070] In some embodiments of this utility model, such as Figure 2 As shown, the overlapping portion 501 and the negative electrode head 21 are directly opposite each other in the thickness direction of the negative electrode head 21, so that the overlapping portion 501 is set close to the negative electrode head 21 to ensure the wrapping effect of the diaphragm assembly 5 on the negative electrode head 21.

[0071] In this process, after the positive electrode 10, the negative electrode 20 and the separator assembly 5 are wound together, the thickness direction of the negative electrode 20 is different at different positions, while the thickness direction of the negative electrode head 21 refers to the thickness direction of the negative electrode 20 at that position, that is, the thickness direction of the negative electrode head 21 is constant.

[0072] Specifically, when the diaphragm assembly 5 shrinks due to heat, the overlapping portion 501 unfolds under force, which facilitates the diaphragm assembly 5 to stably wrap the negative electrode head 21. This prevents the diaphragm assembly 5 from shrinking and failing to continue wrapping the negative electrode head 21, thus ensuring the wrapping effect of the diaphragm assembly 5 on the negative electrode head 21. This reduces the possibility that positive ions at the positive electrode plate 10 will accumulate at the negative electrode head 21, reduces the possibility that metal will accumulate at the negative electrode head 21, and reduces the possibility that metal burrs at the negative electrode head 21 will come into contact with the positive electrode plate 10.

[0073] In some embodiments of this utility model, the number of overlapping portions 501 can be multiple. For example, multiple overlapping portions 501 can be arranged at intervals in the winding direction of the winding pole core 1, or there can be only one. This will not be elaborated further here.

[0074] In some embodiments of this utility model, such as Figure 1 , Figure 2 As shown, the positive electrode 10 has a positive electrode head 161 located inside the wound electrode core 1, and the positive electrode head 161 and the negative electrode head 21 are arranged opposite to each other in the thickness direction of the negative electrode head 21.

[0075] In some embodiments, such as Figure 2 , Figure 9 and Figure 10 As shown, in the thickness direction of the negative electrode head 21, the overlapping portion 501 is located on the side of the negative electrode head 21 facing the positive electrode head 161. That is, in the thickness direction of the negative electrode head 21, the overlapping portion 501 is located between the negative electrode head 21 and the positive electrode head 161, so as to utilize the space between the negative electrode head 21 and the positive electrode head 161 to set the overlapping portion 501, thereby facilitating the improvement of the utilization rate of the space inside the wound electrode core 1.

[0076] In some examples, such as Figure 2 As shown, the overlapping portion 501 extends along the winding direction of the wound electrode core 1, and in the thickness direction of the negative electrode head 21, the overlapping portion 501 is located on the side of the negative electrode head 21 facing the positive electrode head 161.

[0077] Furthermore, the overlapping portion 501 has two layers; or the overlapping portion 501 includes a connected first portion 5011 and a second portion 5012, the overlapping portion 5011 is adapted to be bent, and the first portion 5011 and the second portion 5012 are stacked along the thickness direction of the negative electrode head 21, in which case the overlapping portion 501 has four layers.

[0078] In other embodiments, such as Figure 11 As shown, the overlapping portion 501 is located on the side of the negative electrode head 21 that faces away from the positive electrode head 161.

[0079] In some examples, such as Figure 11As shown, the overlapping portion 501 extends along the winding direction of the wound electrode core 1. In the thickness direction of the negative electrode head 21, the overlapping portion 501 is located on the side of the negative electrode head 21 that is away from the positive electrode head 161.

[0080] Furthermore, the overlapping portion 501 has two layers; or the overlapping portion 501 includes a connected first portion 5011 and a second portion 5012, the overlapping portion 5011 is adapted to be bent, and the first portion 5011 and the second portion 5012 are stacked along the thickness direction of the negative electrode head 21, in which case the overlapping portion 501 has four layers.

[0081] In some embodiments of this utility model, the length of the overlapping portion 501 in the winding direction of the winding pole core 1 is 1mm to 5mm.

[0082] Specifically, if the length of the overlapping portion 501 is too short, it cannot guarantee the separation effect of the diaphragm assembly 5 on the positive electrode 10 and the negative electrode 20 after shrinkage, nor can it guarantee the wrapping effect of the diaphragm assembly 5 on the negative electrode head 21. Therefore, the length of the overlapping portion 501 must be greater than or equal to 1 mm.

[0083] If the length of the overlapping portion 501 is too long, it will cause the overlapping portion 501 to occupy too much space in the wound pole core 1, resulting in low space utilization in the wound pole core 1. Therefore, the length of the overlapping portion 501 must be less than or equal to 5mm.

[0084] In the winding direction of the wound pole core 1, the length of the overlapping portion 501 can be 1mm, 2mm, 3mm, 4mm or 5mm, without much restriction.

[0085] In some embodiments of this utility model, such as Figure 1 , Figure 2 As shown, the membrane assembly 5 includes two membranes 50, which are located on both sides of the negative electrode 20 in the thickness direction. The membranes 50 separate the negative electrode 20 and the positive electrode 10 from each other, preventing direct contact between the positive electrode 10 and the negative electrode 20 and preventing internal short circuits.

[0086] Specifically, a separator 50 is provided on both sides of the negative electrode 20 in the thickness direction so that when the wound electrode core 1 is formed, the outer side of the negative electrode 20 and the inner side of the positive electrode 10 can be separated by the separator 50, and the inner side of the negative electrode 20 and the outer side of the positive electrode 10 can be separated by the separator 50.

[0087] It should be explained here that the inner side and the outer side refer to the sides relative to the central axis of the wound electrode core 1. The side of the negative electrode 20 facing the central axis of the wound electrode core 1 in the thickness direction is the inner side of the negative electrode 20, and the side of the negative electrode 20 facing away from the central axis of the wound electrode core 1 in the thickness direction is the outer side of the negative electrode 20. Similarly, the side of the positive electrode 10 facing the central axis of the wound electrode core 1 in the thickness direction is the inner side of the positive electrode 10, and the side of the positive electrode 10 facing away from the central axis of the wound electrode core 1 in the thickness direction is the outer side of the positive electrode 10.

[0088] The separator 50 has a separator head 51 located inside the wound electrode core 1. The separator heads 51 of the two separators 50 are at least partially connected and overlapped to define the overlapping portion 501. At the same time, the separator heads 51 of the two separators 50 wrap around the negative electrode head 21 to separate the negative electrode head 21 from the positive electrode plate 10, thereby fully preventing the negative electrode head 21 from directly contacting the positive electrode plate 10 or the positive electrode active material layer 42, and preventing positive ions in the positive electrode active material layer 42 from being deposited into the negative electrode head 21 that is not coated with negative electrode active material.

[0089] Specifically, when the diaphragm assembly 5 shrinks due to heat, the diaphragm head 51 of the two diaphragms 50 will separate, thereby compensating for the shrinkage of the diaphragm assembly 5, so that the diaphragm assembly 5 can stably wrap the negative electrode head 21 and separate the positive electrode 10 and the negative electrode 20.

[0090] In some embodiments, the membrane heads 51 of the two membrane layers 50 are fixedly connected by thermal bonding technology, for example, by using two thermal bonding blocks to press the two membrane layers 50 together, so that the two membrane layers 50 are bonded together. The thermal bonding blocks can achieve precise control of pressure and temperature, improve the bonding effect between the membrane 50 and the negative electrode 20, improve the safety during the use of the cell, and reduce the space occupied by the membrane 50 and empty foil inside the wound electrode core 1 through this process, which is conducive to increasing the capacity of the wound electrode core 1.

[0091] Specifically, after fixing the membrane head 51 of the two-layer membrane 50 using thermal bonding technology, the two-layer membrane 50 and the negative electrode 20 are cut off simultaneously using a cutter.

[0092] Furthermore, when the membrane heads 51 of the two membranes 50 are fixedly connected by thermal bonding technology to form an overlapping portion 501, the overlapping portion 501 has already been processed in a high-temperature environment. When the winding electrode core 1 is charged and discharged, the winding electrode core 1 generates heat. When the temperature rises, it is easier to make the overlapping portion 501 deform to a smaller extent, thereby reducing the possibility of internal short circuit of the winding electrode core 1 caused by thermal shrinkage of the overlapping portion 501. This ensures that the overlapping portion 501 can reliably compensate for the shrinkage of the membrane assembly 5 after the membrane assembly 5 is thermally shrinked.

[0093] What needs to be explained here is that... Figure 2 To facilitate observation of the positions of the diaphragm heads 51 and the overlapping portion 501, the two diaphragm heads 51 are separated during drawing. In reality, the two diaphragm heads 51 are adapted to be connected together to form the overlapping portion 501.

[0094] In some optional embodiments of this utility model, such as Figures 9-13 As shown, the overlapping portion 501 is located on one side of the thickness direction of the negative electrode head 21. A portion of the overlapping portion 501 extends along the winding direction of the winding electrode core 1, and another portion is bent in the direction away from the negative electrode head 21, or another portion is bent in the direction close to the negative electrode head 21.

[0095] In other words, the overlapping portion 501 is suitable for bending and overlapping again, which helps to reduce the space occupied by the overlapping portion 501 in the winding direction of the winding electrode core 1. By utilizing the space in the thickness direction of the negative electrode head 21, the length of the overlapping portion 501 is made longer. Thus, when the diaphragm assembly 5 shrinks after being heated, the overlapping portion 501 can extend, thereby compensating for the shrinkage of the diaphragm assembly 5. This ensures the reliability of the diaphragm assembly 5 in separating the positive electrode sheet 10 and the negative electrode sheet 20, improves the reliability of the diaphragm assembly 5 in wrapping the negative electrode head 21, avoids leakage of the negative electrode head 21, and reduces the risk of metal accumulation at the negative electrode head 21 and the possibility of metal burrs at the negative electrode head 21 coming into contact with the positive electrode sheet 10.

[0096] In some embodiments, such as Figure 9 , Figure 10 , Figure 12 and Figure 13 As shown, the overlapping portion 501 has four layers. The overlapping portion 501 includes a first portion 5011 and a second portion 5012 that are connected. The first portion 5011 and the second portion 5012 are stacked in the thickness direction of the negative electrode head 21.

[0097] Specifically, the diaphragm assembly 5 includes two diaphragms 50, which are located on both sides of the negative electrode 20 in the thickness direction. The diaphragm heads 51 of the two diaphragms 50 are at least partially connected and overlap. The overlapping diaphragms 50 define a connected first part 5011 and a second part 5012. The first part 5011 and the second part 5012 are stacked in the thickness direction of the negative electrode head 21. Therefore, the overlapping part 501 has four layers. Of course, the stacked part 501 can also have other numbers of layers, such as six layers, eight layers, etc. There are no restrictions here.

[0098] In some examples, such as Figure 9As shown, the overlapping portion 501 is located on the side of the negative electrode head 21 facing the positive electrode head 161 in the thickness direction of the negative electrode head 21. The first portion 5011 and the second portion 5012 are stacked in the thickness direction of the negative electrode head 21. The second portion 5012 is bent in the direction away from the negative electrode head 21, that is, the second portion 5012 is located on the side of the first portion 5011 away from the negative electrode head 21.

[0099] In some examples, such as Figure 10 As shown, the overlapping portion 501 is located on the side of the negative electrode head 21 facing the positive electrode head 161 in the thickness direction of the negative electrode head 21. The first portion 5011 and the second portion 5012 are stacked in the thickness direction of the negative electrode head 21. The second portion 5012 is bent towards the side closer to the negative electrode head 21, that is, the second portion 5012 is located on the side of the first portion 5011 facing the negative electrode head 21, and the second portion 5012 is located between the first portion 5011 and the negative electrode head 21.

[0100] In some examples, such as Figure 12 As shown, the overlapping portion 501 is located on the side of the negative electrode head 21 that is away from the positive electrode head 161 in the thickness direction of the negative electrode head 21. The first portion 5011 and the second portion 5012 are stacked in the thickness direction of the negative electrode head 21. The second portion 5012 is bent in the direction away from the negative electrode head 21, that is, the second portion 5012 is located on the side of the first portion 5011 that is away from the negative electrode head 21.

[0101] In some examples, such as Figure 13 As shown, the overlapping portion 501 is located on the side of the negative electrode head 21 facing away from the positive electrode head 161 in the thickness direction of the negative electrode head 21. The first portion 5011 and the second portion 5012 are stacked in the thickness direction of the negative electrode head 21. The second portion 5012 is bent towards the side closer to the negative electrode head 21, that is, the second portion 5012 is located on the side of the first portion 5011 facing the negative electrode head 21. The second portion 5012 is located between the first portion 5011 and the negative electrode head 21.

[0102] In other embodiments of this utility model, such as Figure 8 As shown, the diaphragm assembly 5 includes a diaphragm 51. In the winding direction of the winding electrode core 1, the length of the diaphragm 51 is greater than the length of the negative electrode sheet 20, so that the diaphragm 51 can bypass the negative electrode head 21 and extend to both sides of the negative electrode sheet 20 in the thickness direction, thereby wrapping the negative electrode head 21.

[0103] Specifically, when forming the wound electrode core 1, the diaphragm 50 can separate the outer side of the negative electrode 20 from the inner side of the positive electrode 10, separate the inner side of the negative electrode 20 from the outer side of the positive electrode 10, and separate the positive electrode 10 from the negative electrode head 21.

[0104] In some embodiments of this utility model, a non-active material layer 41 is provided in a portion of the positive electrode sheet 10 facing the central axis of the coiled electrode core, and at least a portion of the negative electrode head 21 is disposed opposite to the non-active material layer 41, so as to separate the positive electrode sheet 10 and the negative electrode head 21 of the negative electrode sheet 20 by means of the non-active material layer 41.

[0105] In this configuration, the side of the positive electrode 10 facing the central axis of the coiled electrode core 1 in the thickness direction is the inner side of the positive electrode 10, and the side of the positive electrode 10 facing away from the central axis of the coiled electrode core 1 in the thickness direction is the outer side of the positive electrode 10; the side of the negative electrode 20 facing the central axis of the coiled electrode core 1 in the thickness direction is the inner side of the negative electrode 20, and the side of the negative electrode 20 facing away from the central axis of the coiled electrode core 1 in the thickness direction is the outer side of the negative electrode 20.

[0106] Specifically, the positive electrode 10 is coated with a positive active material layer 42 on its side surface in the thickness direction, and the negative electrode 20 is coated with a negative active material layer 43 on its side surface in the thickness direction. However, the end face of the negative electrode head 21 of the negative electrode 20 is not coated with the negative active material layer 43.

[0107] Therefore, when positive ions move in the wound electrode core 1, positive ions in the positive electrode active material layer 42 that is closer to the negative electrode head 21 may reach the end face of the negative electrode head 21 and be deposited at the end face of the negative electrode head 21, forming a metal accumulation at the negative electrode head 21.

[0108] In other words, when positive ions reach the negative electrode head 21 where no negative electrode active material is coated, on the one hand, the positive ions cannot continue to move, affecting the capacity of the wound electrode core 1; on the other hand, when the metal at the negative electrode head 21 accumulates to a certain length, the accumulated metal will directly connect the positive electrode 10 and the negative electrode 20, causing an internal short circuit in the wound electrode core 1.

[0109] Therefore, in this embodiment, by providing an inactive material layer 41 in a portion of the inner side of the positive electrode 10 and wrapping the negative electrode head 21 with the separator assembly 5, when the positive electrode 10 and the negative electrode 20 are wound together to form the wound electrode core 1, at least a portion of the negative electrode head 21 can be directly opposite the inactive material layer 41 and the separator assembly 5. Thus, the inactive material layer 41 and the separator assembly 5 separate at least a portion of the negative electrode head 21 and the positive electrode 10, reducing the possibility that positive ions at the positive electrode 10 will accumulate at the negative electrode head 21.

[0110] In some embodiments, such as Figure 1As shown, when winding the positive electrode 10 and the negative electrode 20 to form the wound electrode core 1, the negative electrode 20 is wound first, and then the positive electrode 10 is inserted, so that the positive electrode 10 and the negative electrode 20 are wound together. By controlling the position of the inactive material layer 41 in the winding direction of the positive electrode 10, when the positive electrode 10 and the negative electrode 20 are wound together, at least a portion of the negative electrode head 21 can be aligned with the inactive material layer 41 on the positive electrode 10, thereby using the inactive material layer 41 and the separator assembly 5 to separate at least a portion of the negative electrode head 21 and the positive electrode 10.

[0111] Specifically, the positive electrode 10 has a positive electrode head 161. After the winding core 1 is formed, the negative electrode head 21 is oriented opposite to the positive electrode head 161. The negative electrode head 21 is directly opposite to the positive electrode corner 18 of the innermost ring of the positive electrode 10 that is closest to the positive electrode head 161. The positive electrode head 161 is directly opposite to the negative electrode corner 28 of the innermost ring of the negative electrode 20 that is closest to the negative electrode head 21. The inactive material layer 41 covers the inner side of the positive electrode corner 18 of the positive electrode 10 so that the inactive material layer 41 is directly opposite to the negative electrode head 21, thereby separating the positive electrode 10 and the negative electrode head 21 by the inactive material layer 41.

[0112] It should be explained here that the positive electrode 10 can be coated with positive active material layer 42 on both sides of the thickness direction, and the negative electrode 20 can be coated with negative active material layer 43 on both sides of the thickness direction; or the positive electrode 10 can be coated with positive active material layer 42 on one side of the thickness direction, and the negative electrode 20 can be coated with negative active material layer 43 on one side of the thickness direction. No further restrictions are imposed here.

[0113] Furthermore, burrs are easily formed at both ends of the negative electrode 20 after cutting. If the burrs come into contact with the positive electrode 10 or the positive active material layer 42 on the positive electrode 10, it will cause a short circuit failure in the wound electrode core 1. Therefore, in this embodiment, an inactive material layer 41 is provided on the positive electrode 10, so that at least a portion of the negative electrode head 21 is directly opposite to the inactive material layer 41. The inactive material layer 41 separates the negative electrode head 21 and the positive electrode 10, reducing the possibility that the metal burrs at the negative electrode head 21 will come into contact with the positive electrode 10, thereby facilitating the improvement of the yield of the wound electrode core 1 and improving the stability of the operation of the wound electrode core 1.

[0114] In the prior art, in order to separate the negative electrode head and the positive electrode plate, insulating tape is applied to the corresponding position of the positive electrode plate 10. However, the insulating tape is prone to wrinkles, and during the use of the wound electrode core, the adhesiveness of the insulating tape will gradually decrease, posing a risk of falling off, which will lead to a significant safety risk to the wound electrode core 1.

[0115] In this embodiment, an inactive material layer 41 is formed on the positive electrode 10, and the inactive material layer 41 is used to replace the insulating tape. Since the inactive material layer 41 has the advantages of being flat and not easy to fall off, it is easy to reduce the safety risks of the wound electrode core 1.

[0116] In some embodiments of this utility model, the material of the inactive material layer 41 is formed of a non-conductive material, such as a polymer material or an inorganic non-metallic material.

[0117] In some embodiments of this utility model, such as Figure 1 , Figure 2 As shown, in the winding direction of the wound electrode core 1, the inactive material layer 41 extends to be directly opposite at least one side of the negative electrode head 21 in the thickness direction. This ensures that the inactive material layer 41 and the negative electrode head 21 face each other, so that the inactive material layer 41 can fully separate the positive electrode 10 and the negative electrode 20. This reduces the possibility of metal accumulation at the negative electrode head 21 and reduces the possibility that burrs at the negative electrode head 21 will directly contact the positive electrode 10.

[0118] It needs to be explained here that after the positive electrode 10, negative electrode 20, and separator assembly 5 are wound, the thickness directions of the positive electrode 10, negative electrode 20, and separator assembly 5 are different at different locations. Specifically, before or after winding, the surfaces of the positive electrode 10, negative electrode 20, and separator assembly 5 on one side of the thickness direction are the same. The extension of the inactive material layer 41 refers to its extension in the winding direction of the wound electrode core 1. When the positive electrode 10 is unwound, the winding direction of the wound electrode core 1 is... Figure 4 In the Y direction, the thickness direction of the negative electrode 20 is as follows: Figure 4 The X direction in the equation.

[0119] In some optional embodiments of this utility model, such as Figure 1 , Figure 2 As shown, in the winding direction of the core 1, the inactive material layer 41 is arranged around the negative electrode head 21, so that the negative electrode head 21 is positioned opposite to the inactive material layer 41 on both sides in the thickness direction of the negative electrode head 21. In this way, in the winding direction of the core 1, the inactive material layer 41 can cover the end of the negative electrode head 21, thereby completely separating the negative electrode head 21 and the positive electrode plate 10. This prevents positive ions from reaching the negative electrode head 21, prevents the formation of metal accumulation at the negative electrode head 21, and prevents the metal accumulation at the negative electrode head 21 from contacting the positive electrode plate 10, causing an internal short circuit in the core 1. At the same time, it can completely separate the burrs at the negative electrode head 21 from the positive electrode plate 10, preventing the burrs at the negative electrode head 21 from directly contacting the positive electrode plate 10.

[0120] In some embodiments, such as Figure 1 , Figure 2 As shown, the inactive material layer 41 in the wound electrode core 1 is located in the positive electrode corner 18 inside the wound electrode core 1 in the positive electrode sheet 10. The negative electrode head 21 of the negative electrode sheet 20 is located at the end of the straight portion on the negative electrode sheet 20. The two ends of the inactive material layer 41 on the positive electrode corner 18 extend to the opposite sides of the negative electrode head 21 in the thickness direction, so that the inactive material layer 41 can cover the end of the negative electrode head 21, thereby fully separating the negative electrode head 21 and the positive electrode sheet 10. This can prevent the metal accumulated at the negative electrode head 21 from contacting the positive electrode sheet 10, and prevent the burrs at the negative electrode head 21 from directly contacting the positive electrode sheet 10.

[0121] In some optional embodiments of this utility model, in the height direction of the wound electrode core 1, the height of the inactive material layer 41 is not lower than the height of the negative electrode head 21, so as to fully separate the negative electrode head 21 and the positive electrode sheet 10, thereby reducing the possibility of metal accumulation at the negative electrode head 21 and reducing the possibility that the burrs at the negative electrode head 21 will directly contact the positive electrode sheet 10.

[0122] In some embodiments, such as Figure 3 As shown, in the winding direction of the core 1, the inactive material layer 41 is adapted to extend around the negative electrode head 21, so that the opposite sides of the negative electrode head 21 in the thickness direction are directly opposite to the inactive material layer 41. In the height direction of the core 1, the height of the inactive material layer 41 is greater than or equal to the height of the negative electrode head 21, so as to fully separate the negative electrode head 21 and the positive electrode plate 10, thereby reducing the possibility of metal accumulation at the negative electrode head 21 and reducing the possibility that the burrs at the negative electrode head 21 will directly contact the positive electrode plate 10.

[0123] The height direction of the wound pole core 1 refers to the extension direction of the central axis of the wound pole core.

[0124] In some optional embodiments of this utility model, such as Figure 2 As shown, in the winding direction of the wound electrode core 1, the distance between the end of the inactive material layer 41 and the negative electrode head 21 that is directly opposite to the thickness direction of the negative electrode head 21 is L1, which is greater than 2mm, so as to ensure that the inactive material layer 41 covers the end of the negative electrode head 21 to a certain extent. In this way, the inactive material layer 41 can fully separate the negative electrode head 21 and the positive electrode plate 10. This can prevent the metal accumulated at the negative electrode head 21 from contacting the positive electrode plate 10 and prevent the burrs at the negative electrode head 21 from directly contacting the positive electrode plate 10.

[0125] In some embodiments, in the winding direction of the wound electrode core 1, the inactive material layer 41 is disposed around the negative electrode head 21, such that the negative electrode head 21 is disposed opposite to the inactive material layer 41 on both sides in the thickness direction of the negative electrode head 21, that is, the distance between the two ends of the inactive material layer 41 in the thickness direction of the negative electrode head 21 and the negative electrode head 21 is greater than 2mm.

[0126] In some optional embodiments of this utility model, the positive electrode 10 includes a current collector, which includes a coating area and a cleaning area 17. The coating area has a positive active material layer 42, and the inactive material layer 41 is a coating provided in the cleaning area 17. This makes it difficult for the inactive material layer 41 to fall off the positive electrode 10, thereby improving the stability of the inactive material layer 41 separating the negative electrode head 21 and the positive electrode 10.

[0127] In some embodiments, the current collector is aluminum foil.

[0128] In some embodiments, such as Figures 5-7 As shown, the inner side of the current collector is at least coated with a positive electrode active material to form a positive electrode active material layer 42 on the inner side of the current collector. After coating the inner side of the current collector with the positive electrode active material, a portion of the inner side of the current collector can be laser-cleaned to form a layer as shown. Figure 5 The clean area 17 shown has an inactive material layer 41, which is a coating applied to the clean area 17.

[0129] Specifically, after forming the clean area 17, an inactive material can be coated on the clean area 17 to form an inactive material layer 41 on the inside of the current collector. When the positive electrode 10 and the negative electrode 20 are wound together to form the wound electrode core 1, at least a portion of the inactive material layer 41 is directly opposite the negative electrode head 21 to separate the positive electrode 10 and the negative electrode head 21, thereby reducing the possibility of metal accumulation at the negative electrode head 21 and reducing the possibility of burrs at the negative electrode head 21 directly contacting the positive electrode 10.

[0130] In contrast to the prior art of attaching insulating tape to the inside of the current collector, this embodiment uses laser to clean a portion of the positive electrode active material layer 42 and then coats an inactive material layer 41 in the cleaned area 17. This improves the accuracy range of the cleaned area 17, ensures the integrity of removing at least part of the positive electrode active material layer 42, and facilitates increasing the capacity of the wound electrode core 1.

[0131] In some embodiments, the thickness of the inactive material layer 41 may be greater than, equal to, or less than the positive electrode active material layer 42, without further restrictions.

[0132] In some embodiments of this utility model, such as Figure 1 , Figure 3 As shown, the negative electrode 20 has a negative electrode tail 22 located outside the wound electrode core 1. In the winding direction of the wound electrode core 1, the positive electrode 10 has an outer region 11 and an inner region 12 extending beyond the negative electrode tail 22. The inner region 12 is located on the side of the outer region 11 facing the central axis of the wound electrode core. At least one of the sides of the outer region 11 and the inner region 12 facing each other is provided with an insulating protection portion 30, so as to separate the positive electrode 10 and the negative electrode tail 22 by means of the insulating protection portion 30, so as to prevent the burrs of the negative electrode tail 22 from contacting the outer region 11 or the inner region 12 of the positive electrode 10, thereby reducing the possibility of the burrs of the negative electrode tail 22 contacting the positive electrode 10 and reducing the possibility of internal short circuit in the wound electrode core 1.

[0133] In some embodiments, the insulating protection part 30 is an insulating tape, which facilitates the adhesive fixation of the insulating protection part 30 to the sides of the outer region 11 and the inner region 12 facing each other, so as to play the role of insulation and isolation.

[0134] In some optional embodiments of this utility model, such as Figure 1 , Figure 4 As shown, the positive electrode 10 has a positive electrode head 161 located inside the wound electrode core 1. The positive electrode 10 also has a first connection region 13 and a second connection region 14. The first connection region 13 connects the inner region 12 and the positive electrode head 161, and the second connection region 14 connects the inner region 12 and the outer region 11.

[0135] The positive electrode 10 also has a positive electrode tail 162 located outside the wound electrode core 1, and the tail end of the outer region 11 defines the positive electrode tail 162.

[0136] In some embodiments, the positive electrode 10 includes a current collector, which forms an outer region 11, an inner region 12, a first connection region 13, and a second connection region 14 after being wound.

[0137] In some embodiments, such as Figure 4 , Figure 7 As shown, the first connection region 13 is coated with a positive electrode active material layer 42 on the side facing the negative electrode tail 22, and the insulating protection part 30 covers at least a portion of the positive electrode active material layer 42.

[0138] Specifically, the tail of the first connecting region 13 is connected to the head of the inner region 12. The side of the first connecting region 13 facing the negative electrode tail 22 is coated with a positive electrode active material layer 42. The insulating protection part 30 is adapted to cover at least a portion of the first connecting region 13 and at least a portion of the inner region 12, so that at least a portion of the insulating protection part 30 is directly opposite the negative electrode tail 22 in the thickness direction of the negative electrode tail 22, thereby using the insulating protection part 30 to separate the negative electrode tail 22 from the positive electrode sheet 10 and the positive electrode active material layer 42.

[0139] In this embodiment, the negative electrode sheet 20 is coated with a negative electrode active material layer 43 on its surface in the thickness direction. However, the end face of the negative electrode tail 22 of the negative electrode sheet 20 is not coated with a negative electrode active material. When positive ions in the wound electrode core 1 move, positive ions in the positive electrode active material layer 42 that are closer to the negative electrode tail 22 may reach the end face of the negative electrode tail 22 and be deposited there, forming a metal accumulation at the negative electrode tail 22.

[0140] In other words, when positive ions reach the negative electrode tail 22 where the negative electrode active material layer 43 is not coated, on the one hand, the positive ions will be unable to continue moving, affecting the capacity of the wound electrode core 1; on the other hand, when the metal at the negative electrode tail 22 accumulates to a certain length, the accumulated metal will directly connect the positive electrode 10 and the negative electrode 20, causing an internal short circuit in the wound electrode core 1.

[0141] Since the extension of the inner region 12 extends beyond the negative electrode tail 22, the head of the inner region 12 is adapted to be directly opposite the negative electrode tail 22 in the thickness direction of the negative electrode tail 22. In this embodiment, an insulating protection part 30 is provided on the side of the inner region 12 facing the negative electrode tail 22, so that the insulating protection part 30 covers part of the positive electrode active material layer 42 of the first connection region 13 and at least part of the inner region 12, so that the insulating protection part 30 can completely separate the negative electrode tail 22 from the positive electrode plate 10 and the positive electrode active material layer 42, so as to prevent positive ions at the positive electrode plate 10 from accumulating in the negative electrode tail 22 and prevent the burrs of the negative electrode tail 22 from directly contacting the positive electrode plate 10.

[0142] It needs to be explained here that after the positive electrode 10, negative electrode 20 and separator assembly 5 are wound, the thickness direction of the negative electrode 20 is different at different positions, while the thickness direction of the negative electrode tail 22 refers to the thickness direction of the negative electrode 20 at that position, that is, the thickness direction of the negative electrode tail 22 is constant.

[0143] In some examples, such as Figure 7 As shown, the insulating protection part 30 covers a portion of the positive electrode active material layer 42 facing the negative electrode tail 22 and the end face of the tail end of the positive electrode active material layer 42, so as to fully separate the negative electrode tail 22 from the positive electrode plate 10 and the positive electrode active material layer 42, preventing the burrs of the negative electrode tail 22 from directly contacting the positive electrode plate 10 and the positive electrode active material layer 42, and at the same time preventing positive ions from being deposited to the end face of the negative electrode tail 22, preventing the formation of metal accumulation in the negative electrode tail 22, and preventing the accumulated metal from directly electrically connecting the positive electrode plate 10, the positive electrode active material layer 42 and the negative electrode plate 20 when the metal accumulation reaches a certain length, causing an internal short circuit in the wound electrode core 1.

[0144] In some embodiments, such as Figure 4 , Figure 7 As shown, the second connection region 14 is coated with a positive electrode active material layer 42 on the side facing the negative electrode tail 22, and the insulating protection part 30 covers at least a portion of the positive electrode active material layer 42.

[0145] Specifically, the tail of the second connection region 14 is connected to the head of the outer region 11. The side of the second connection region 14 facing the negative electrode tail 22 is coated with a positive electrode active material layer 42. The insulating protection part 30 is adapted to cover at least a portion of the second connection region 14 and at least a portion of the outer region 11, so that at least a portion of the insulating protection part 30 is directly opposite the negative electrode tail 22 in the thickness direction of the negative electrode tail 22, thereby using the insulating protection part 30 to separate the negative electrode tail 22 from the positive electrode sheet 10 and the positive electrode active material layer 42.

[0146] In this process, the negative electrode sheet 20 is coated with a negative electrode active material layer 43 on its surface in the thickness direction. However, the end face of the negative electrode tail 22 of the negative electrode sheet 20 is not coated with the negative electrode active material layer 43. When the positive ions in the wound electrode core 1 move, the positive ions in the positive electrode active material layer 42 that are closer to the negative electrode tail 22 may reach the end face of the negative electrode tail 22 and be deposited there, forming a metal accumulation at the negative electrode tail 22.

[0147] In other words, when positive ions reach the tail 22 of the negative electrode where no negative electrode active material is coated, on the one hand, the positive ions will be unable to continue moving, which will affect the capacity of the wound electrode core 1. On the other hand, when the metal at the tail 22 of the negative electrode accumulates to a certain length, the accumulated metal will directly connect the positive electrode 10 and the negative electrode 20, causing an internal short circuit in the wound electrode core 1.

[0148] Since the outer region 11 extends beyond the negative electrode tail 22, the head of the outer region 11 is adapted to face the negative electrode tail 22 in the thickness direction of the negative electrode tail 22. In this application, an insulating protection part 30 is provided on the side of the outer region 11 facing the negative electrode tail 22, so that the insulating protection part 30 covers part of the positive electrode active material layer 42 of the second connection region 14 and at least part of the outer region 11, so that the insulating protection part 30 can completely separate the negative electrode tail 22 from the positive electrode plate 10 and the positive electrode active material layer 42, so as to prevent positive ions at the positive electrode plate 10 from accumulating in the negative electrode tail 22 and prevent the burrs of the negative electrode tail 22 from directly contacting the positive electrode plate 10.

[0149] In some examples, such as Figure 7As shown, the insulating protection part 30 covers a portion of the positive electrode active material layer 42 facing the negative electrode tail 22 and the end face of the tail end of the positive electrode active material layer 42, so as to fully separate the negative electrode tail 22 from the positive electrode plate 10 and the positive electrode active material layer 42, preventing the burrs of the negative electrode tail 22 from directly contacting the positive electrode plate 10 and the positive electrode active material layer 42, and at the same time preventing positive ions from being deposited to the end face of the negative electrode tail 22, preventing the formation of metal accumulation in the negative electrode tail 22, and preventing the accumulated metal from directly electrically connecting the positive electrode plate 10 and the negative electrode plate 20 when the metal accumulation reaches a certain length, causing an internal short circuit in the wound electrode core 1.

[0150] In some examples, the first connection region 13 has a positive active material layer 42 on both the inner and outer sides, the inactive material layer 41 is located on the inner side of the first connection region 13, and the inner layer of the second connection region 14 has a positive active material layer 42.

[0151] The inner and outer sides of the inner region 12 can be either empty foil regions or positive electrode active material layer 42. The inner and outer sides of the outer region can also be either empty foil regions or positive electrode active material layer 42; no further restrictions are imposed here.

[0152] In some specific embodiments of this utility model, such as Figure 3 As shown, in the winding direction of the wound electrode core 1, the overlap length between the insulating protection part 30 and the positive electrode active material layer 42 is L2, where L2 > 1 mm, to ensure that the insulating protection part 30 can fully separate the positive electrode active material layer 42 and the negative electrode tail 22 on the positive electrode sheet 10, so as to prevent the burrs of the negative electrode tail 22 from directly contacting the positive electrode sheet 10 and the positive electrode active material layer 42, and to prevent the positive ions in the positive electrode active material layer 42 from being deposited into the negative electrode tail 22 which is not coated with negative electrode active material.

[0153] Specifically, the positive electrode 10 is coated with a positive active material on both sides in the thickness direction, so that a positive active material layer 42 is formed on both sides of the positive electrode 10 in the thickness direction. The negative electrode 20 is coated with a negative active material on both sides in the thickness direction, so that a negative active material layer 43 is formed on both sides of the negative electrode 20.

[0154] In some embodiments, the inner and outer sides of the first connection region 13 are provided with positive electrode active material layers 42, the inactive material layer 41 is located inside the first connection region 13, the inner side of the inner region 12 and the inner layer of the second connection region 14 are provided with positive electrode active material layers 42, and the outer side of the inner region 12, the outer side of the second connection region 14 and the outer side of the outer region 11 are empty foil regions 15.

[0155] Specifically, the area of ​​the positive electrode active material layer 42 on the positive electrode 10 and the area of ​​the negative electrode active material layer 43 on the negative electrode 20 are similar to maintain the balance of ions and electrons inside the battery, ensure that the charging and discharging process is efficient and safe, and prevent the occurrence of harmful side reactions.

[0156] In this configuration, the positive electrode 10 is slightly longer than the negative electrode 20. When the positive electrode 10 and the negative electrode 20 are wound together to form a wound cell, the inner region 12 is located inside the negative electrode tail 22, and the outer sides of the first connecting region 13 and the inner region 12 face the negative electrode tail 22. The outer region 11 is located outside the negative electrode tail 22, and the inner sides of the outer region 11 and the second connecting region 14 face the negative electrode tail 22.

[0157] Both the outer region 11 and the inner region 12 are provided with an insulating protection part 30 on the side facing the negative electrode tail 22. The insulating protection part 30 overlaps at least partially with the positive electrode active material layer 42 on the outer side of the first connection region 13, and the overlap length is greater than 1 mm. The insulating protection part 30 overlaps at least partially with the positive electrode active material layer 42 on the inner side of the second connection region 14, and the overlap length is greater than 1 mm.

[0158] It needs to be explained here that "inner side" and "outer side" are relative to the central axis of the wound electrode core 1. "Inner region 12 is located inside the negative electrode tail 22" means that the inner region 12 is located on the side of the negative electrode tail 22 facing the central axis of the wound electrode core 1. "Outer region 11 is located outside the negative electrode tail 22" means that the outer region 11 is located on the side of the negative electrode tail 22 facing away from the central axis of the wound electrode core 1.

[0159] In some optional embodiments of this utility model, such as Figure 3 As shown, at least a portion of the insulating protection portion 30 overlaps with the negative electrode 20 in the thickness direction of the negative electrode 20 to fully separate the negative electrode tail 22 from the positive electrode 10 and the positive electrode active material layer 42, so as to prevent the burrs of the negative electrode tail 22 from directly contacting the positive electrode 10 and the positive electrode active material layer 42, and to prevent positive ions in the positive electrode active material layer 42 from being deposited into the negative electrode tail 22 which is not coated with negative electrode active material.

[0160] In some specific embodiments of this utility model, in the thickness direction of the negative electrode sheet 20, insulating protective portions 30 are provided on both sides of the negative electrode tail 22 to fully separate the negative electrode tail 22 from the positive electrode sheet 10 and the positive electrode active material layer 42, so as to prevent the burrs of the negative electrode tail 22 from directly contacting the positive electrode sheet 10 and the positive electrode active material layer 42, and to prevent the positive ions in the positive electrode active material layer 42 from being deposited into the negative electrode tail 22 that is not coated with negative electrode active material.

[0161] Specifically, both the outer region 11 and the inner region 12 are provided with an insulating protection part 30 on the side facing the negative electrode tail 22. The insulating protection part 30 overlaps at least partially with the positive electrode active material layer 42 on the outer side of the first connection region 13 and at least partially with the negative electrode sheet 20. The insulating protection part 30 overlaps at least partially with the positive electrode active material layer 42 on the inner side of the second connection region 14 and at least partially with the negative electrode sheet 20.

[0162] In some specific embodiments of this utility model, such as Figure 3 As shown, in the winding direction of the wound electrode core 1, the overlap length between the insulating protective part 30 and the negative electrode sheet 20 is L3, where L3 > 2mm, so as to fully separate the negative electrode tail 22 and the positive electrode active material layer 42, so as to prevent the burrs of the negative electrode tail 22 from directly contacting the positive electrode sheet 10 and the positive electrode active material layer 42, and to prevent the positive ions in the positive electrode active material layer 42 from being deposited into the negative electrode tail 22 that is not coated with negative electrode active material.

[0163] Specifically, in the winding direction of the wound electrode core 1, one end of the insulating protection part 30 is located on the positive electrode active material layer 42, and the other end of the insulating protection part 30 extends beyond the negative electrode tail 22 and covers at least part of the outer region 11 or the inner region 12, so that the overlap length between the insulating protection part 30 and the negative electrode sheet 20 is greater than 2 mm, so that the distance between the end of the insulating protection part 30 located on the positive electrode active material layer 42 and the negative electrode tail 22 is greater than 2 mm, thereby enabling the insulating protection part 30 to fully cover the insulating protection part 30 near the end of the negative electrode tail 22, preventing the burrs of the negative electrode tail 22 from directly contacting the positive electrode sheet 10 and the positive electrode active material layer 42, and preventing positive ions in the positive electrode active material layer 42 from being deposited to the negative electrode tail 22 which is not coated with negative electrode active material.

[0164] In some optional embodiments of this utility model, such as Figure 3 , Figure 4 As shown, the inner region 12 and the outer region 11 have empty foil areas 15 on their sides facing each other. The insulating protection part 30 covers at least a portion of the empty foil area 15 to ensure that the extension of the insulating protection part 30 exceeds the negative electrode tail 22. That is, at least a portion of the insulating protection part 30 is directly opposite the negative electrode tail 22 in the thickness direction of the negative electrode tail 22, so as to prevent the burrs of the negative electrode tail 22 from directly contacting the positive electrode sheet 10 and the positive electrode active material layer 42, and to prevent positive ions in the positive electrode active material layer 42 from being deposited into the negative electrode tail 22 which is not coated with negative electrode active material.

[0165] In some embodiments, such as Figure 1 , Figure 8As shown, the side of the outer region 11 facing the inner region 12 and the side away from the inner region 12 are both empty foil areas 15. The outer region 11 extends to form the outermost layer of the wound electrode core 1. The length of the outer region 11 exceeds the circumference of the outermost circumference of the wound electrode core 1, so as to facilitate fixing the tail end of the outer region 11 to the empty foil area 15 of the positive electrode sheet 10, thereby positioning the wound electrode core 1.

[0166] At the same time, the outer area 11 can be used to protect the wound electrode core 1, improve the ability of the wound electrode core 1 to resist external forces, and prevent external foreign particles from piercing the wound electrode core 1 and causing safety risks.

[0167] In this way, the inner and outer sides of the outer region 11 are both empty foil regions 15, and the outer side of the inner region 12 is an empty foil region 15, which can play a role in balancing the thickness of the wound pole core 1.

[0168] In some embodiments, such as Figure 8 As shown, the tail end of the outer region 11 is fixed to the empty foil area 15 of the outer region 11 by the adhesive part 55.

[0169] In some embodiments of this utility model, such as Figure 1 , Figure 2 As shown, the positive electrode 10 has a positive electrode head 161 located inside the wound electrode core 1. In the winding direction of the wound electrode core 1, the positive electrode 10 includes a positive electrode corner portion 18 located inside the wound electrode core 1, and the negative electrode 20 includes a negative electrode corner portion 28 located inside the wound electrode core 1. The positive electrode head 161 and the negative electrode corner portion 28 are arranged opposite each other, and the negative electrode head 21 and the positive electrode corner portion 18 are arranged opposite each other.

[0170] In some embodiments, such as Figure 1 As shown, when winding the positive electrode 10 and the negative electrode 20 to form the wound electrode core 1, the negative electrode 20 is wound first, and then the positive electrode 10 is inserted, so that the positive electrode 10 and the negative electrode 20 are wound together. In this way, after the wound electrode core 1 is formed, the negative electrode head 21 and the positive electrode head 161 are facing opposite directions. The negative electrode head 21 is directly opposite to the positive electrode corner 18 located inside the wound electrode core 1 on the positive electrode 10, and the positive electrode head 161 is directly opposite to the negative electrode corner 28 located inside the wound electrode core 1 on the negative electrode 20.

[0171] In some embodiments of this utility model, such as Figure 1 , Figure 8 As shown, in the height direction of the wound electrode core 1, the end of the positive electrode 10 is provided with at least one positive electrode tab 19, and the end of the negative electrode 20 is provided with at least one negative electrode tab 29, so as to realize the connection between the internal and external circuits of the battery by means of the positive electrode tab 19 and the negative electrode tab 29.

[0172] In some embodiments, such as Figure 1 As shown, in the height direction of the wound electrode core 1, the end of the positive electrode 10 is provided with a positive electrode tab 19, and the end of the negative electrode 20 is provided with a negative electrode tab 29.

[0173] In other embodiments, such as Figure 8 As shown, in the height direction of the wound electrode core 1, the end of the positive electrode sheet 10 is provided with a plurality of positive electrode tabs 19, and the plurality of positive electrode tabs 19 are spaced apart in the winding direction of the positive electrode sheet 10. The end of the negative electrode sheet 20 is provided with a plurality of negative electrode tabs 29, and the plurality of negative electrode tabs 29 are spaced apart in the winding direction of the negative electrode sheet 20.

[0174] The height direction of the wound pole core 1 refers to the extension direction of the central axis of the wound pole core.

[0175] The following describes a battery according to an embodiment of the present invention. The battery according to an embodiment of the present invention includes a housing and a wound electrode core 1 according to the above embodiment of the present invention. The housing has a receiving cavity, and the wound electrode core 1 is disposed in the receiving cavity.

[0176] The battery can be a cylindrical battery, a pouch battery, a square aluminum-cased battery, a steel-cased battery, or other types of batteries; there are no further restrictions here.

[0177] According to the battery of the present invention, by utilizing the wound electrode core 1 of the above embodiment of the present invention, and by making the separator assembly 5 have multiple overlapping portions 501, when the separator assembly 5 is heated and shrinks, the overlapping portions 501 can reserve material for the shrinkage of the separator assembly 5, so as to improve the reliability of the separator assembly 5 in separating the positive electrode 10 and the negative electrode 20, and separating the negative electrode head 21 and the positive electrode 10, thereby reducing the risk of short circuit of the wound electrode core 1 and reducing the possibility of metal accumulation at the negative electrode head 21.

[0178] The following describes a battery assembly according to an embodiment of the present invention. The battery assembly according to an embodiment of the present invention includes the wound electrode core 1 described above in the present invention.

[0179] Specifically, the battery assembly includes multiple batteries that are electrically connected to each other.

[0180] According to the battery assembly of the present invention, by utilizing the battery of the above embodiment of the present invention, by making the separator assembly 5 have multiple overlapping portions 501, when the separator assembly 5 is heated and shrinks, the overlapping portions 501 can reserve material for the shrinkage of the separator assembly 5, thereby improving the reliability of the separator assembly 5 in separating the positive electrode 10 and the negative electrode 20, and separating the negative electrode head 21 and the positive electrode 10, which helps to reduce the risk of short circuit of the wound electrode core 1 and reduce the possibility of metal accumulation at the negative electrode head 21.

[0181] The following describes an electrical device according to an embodiment of the present invention. The electrical device according to an embodiment of the present invention includes the battery or battery assembly described above.

[0182] According to the embodiment of the present invention, the electrical device utilizes a battery or battery assembly according to the above embodiment of the present invention to make the separator assembly 5 have multiple overlapping portions 501. When the separator assembly 5 is heated and shrinks, the overlapping portions 501 can reserve material for the shrinkage of the separator assembly 5, so as to ensure that the separator assembly 5 can separate the positive electrode 10 and the negative electrode 20, separate the negative electrode head 21 and the positive electrode 10, reduce the risk of short circuit of the wound electrode core 1, and reduce the possibility of metal accumulation at the negative electrode head 21.

[0183] The electrical devices mentioned here can include, but are not limited to, mobile phones, tablets, laptops, electric toys, power tools, electric vehicles, electric cars, ships, spacecraft, etc.

[0184] Among them, electric toys can include stationary or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys; spacecraft can include airplanes, rockets, space shuttles, and spacecraft; power tools include metal cutting power tools, grinding power tools, assembly power tools, and railway power tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete vibrators, and electric planers.

[0185] In some embodiments, the electrical device is a vehicle, which may be a pure electric vehicle or a hybrid vehicle.

[0186] Other components and operations of the electrical device according to the embodiments of this utility model are known to those skilled in the art and will not be described in detail here.

[0187] In the description of this utility model, it should be understood that the terms "center," "longitudinal," "transverse," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential," etc., indicating the orientation or positional relationship shown in the accompanying drawings, are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model. Furthermore, features defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this utility model, unless otherwise stated, "a plurality of" means two or more. In the description of this utility model, "above" or "below" a second feature may include direct contact between the first and second features, or it may include contact between the first and second features not being in direct contact but through another feature between them.

[0188] In the description of this utility model, the terms "above", "over" and "on top" for the first feature and the second feature include the first feature being directly above or diagonally above the second feature, or simply indicate that the first feature is at a higher horizontal level than the second feature.

[0189] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0190] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0191] Although embodiments of the present invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the claims and their equivalents.

Claims

1. A wound electrode core, characterized by, The wound pole core (1) includes: Positive electrode (10) and negative electrode (20), the negative electrode (20) having a negative electrode head (21) located inside the wound electrode core (1), at least a portion of the negative electrode head (21) being disposed opposite to a portion of the positive electrode (10) facing the central axis of the wound electrode core; A separator assembly (5) is used to separate the positive electrode plate (10) and the negative electrode plate (20), and the separator assembly (5) wraps around the negative electrode head (21). The diaphragm assembly (5) has multiple overlapping portions (501).

2. The wound core according to claim 1, characterized in that The overlapping portion (501) is located on one side of the thickness direction of the negative electrode head (21); and / or, at least part of the overlapping portion (501) is directly opposite the negative electrode head (21) in the thickness direction of the negative electrode head (21).

3. The wound core of claim 1, wherein The positive electrode sheet (10) has a positive electrode head (161) located inside the wound electrode core (1), and the positive electrode head (161) and the negative electrode head (21) are arranged opposite to each other in the thickness direction of the negative electrode head (21). Wherein, in the thickness direction of the negative electrode head (21), the overlapping portion (501) is located on the side of the negative electrode head (21) facing the positive electrode head (161); or, the overlapping portion (501) is located on the side of the negative electrode head (21) away from the positive electrode head (161).

4. The wound core of claim 1, wherein In the winding direction of the wound pole core (1), the length of the overlapping portion (501) is 1 mm to 5 mm.

5. The wound core according to any one of claims 1 to 4, characterized in that The diaphragm assembly (5) includes two diaphragm layers (50), which are respectively located on both sides of the negative electrode sheet (20) in the thickness direction. The diaphragm (50) has a diaphragm head (51) located inside the wound pole core (1), and the diaphragm heads (51) of the two diaphragms (50) are at least partially connected and overlap to define the overlapping portion (501).

6. The wound core of claim 5, wherein The overlapping portion (501) is located on one side of the thickness direction of the negative electrode head (21). A portion of the overlapping portion (501) extends along the winding direction of the wound electrode core (1), and another portion is bent in the direction away from the negative electrode head (21), or another portion is bent in the direction close to the negative electrode head (21).

7. The wound core of claim 1, wherein The positive electrode sheet (10) has an inactive material layer (41) in a portion of the area facing the central axis of the wound electrode core, and at least a portion of the negative electrode head (21) is positioned opposite the inactive material layer (41).

8. The wound core according to claim 7, characterized in that In the winding direction of the wound electrode core (1), the inactive material layer (41) extends to be positioned opposite at least one side of the negative electrode head (21) in the thickness direction.

9. The wound core of claim 8, wherein In the winding direction of the wound electrode core (1), the inactive material layer (41) is arranged around the negative electrode head (21) such that the negative electrode head (21) is arranged opposite to the inactive material layer (41) on both sides of the negative electrode head (21) in the thickness direction.

10. The wound core of claim 8, wherein In the winding direction of the wound electrode core (1), the distance between the end of the inactive material layer (41) that is directly opposite to the thickness direction of the negative electrode head (21) and the negative electrode head (21) is greater than 2 mm.

11. The wound core of claim 7, wherein In the height direction of the wound electrode core (1), the height of the inactive material layer (41) is not lower than the height of the negative electrode head (21).

12. The wound core of claim 7, wherein The positive electrode (10) includes a current collector, which includes a coating area and a cleaning area (17). The coating area has a positive active material layer (42), and the inactive material layer (41) is a coating material disposed in the cleaning area (17).

13. The wound core of claim 7, wherein The negative electrode (20) has a negative electrode tail (22) located outside the wound electrode core (1). In the winding direction of the wound electrode core (1), the positive electrode (10) has an outer region (11) and an inner region (12) extending beyond the negative electrode tail (22). The inner region (12) is located on the side of the outer region (11) facing the central axis of the wound electrode core (1). At least one of the sides of the outer region (11) and the inner region (12) facing each other is provided with an insulating protection portion (30).

14. The wound core of claim 1, wherein The positive electrode (10) has a positive electrode head (161) located inside the wound electrode core (1). In the winding direction of the wound electrode core (1), the positive electrode (10) includes a positive electrode corner portion (18) located inside the wound electrode core (1), and the negative electrode (20) includes a negative electrode corner portion (28) located inside the wound electrode core (1). The positive electrode head (161) and the negative electrode corner portion (28) are arranged opposite each other, and the negative electrode head (21) and the positive electrode corner portion (18) are arranged opposite each other.

15. A battery, characterized by include: The housing has a receiving cavity; A wound pole core (1), wherein the wound pole core (1) is the wound pole core (1) according to any one of claims 1-14, and the wound pole core (1) is disposed in the receiving cavity.

16. A battery assembly characterized by, It includes the battery and circuit structure of claim 15, wherein the battery and the circuit structure are electrically connected.

17. An electrical device, comprising: It includes the battery of claim 15; or it includes the battery assembly of claim 16.

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