Pole piece and roll core

Abstract

The utility model relates to the technical field of battery energy, in particular to a pole piece and a roll core. The pole piece comprises a current collector, an active substance layer, a tab and a safety coating, the active substance layer is located on at least one side of the surface of the current collector, and the pole piece comprises a double-sided area, a single-sided area and an empty foil area along the length direction of the pole piece; wherein the safety coating is arranged in the empty foil area, and the safety coating is connected with the active substance layer; the safety coating is provided with a first groove, and the tab is located in the first groove. The safety coating is arranged on the surface of the current collector in the empty foil area and is connected with the active substance layer, so that the exposed current collector on the pole piece is covered, the current collector of the pole piece is prevented from being in direct contact with the coating or the current collector of another pole piece, the problems of fire combustion and even explosion of the battery are reduced, the safety performance of the battery is improved, and the service life of the battery is prolonged. And the first grooves for accommodating the tabs are formed in the safety coatings, so that the safety coatings and the tabs are prevented from being overlapped, and the flatness of the prepared roll core is favorably improved.

Description

Technical Field

[0001] The present application relates to the field of battery energy technology, and in particular to a pole piece and a winding core. Background Art

[0002] With the rapid development of battery technology, batteries have been widely used in various fields. The energy density, fast charging capability, and charge and discharge rate of batteries are constantly improving. At the same time, people's safety requirements for batteries are also getting higher and higher.

[0003] At present, some safety tests have found that in the battery, once the positive electrode collector comes into contact with the negative electrode coating or the negative electrode collector, it will release a large amount of energy in a very short time, causing the internal temperature of the battery to rise sharply, causing the battery to catch fire or even explode, seriously affecting the safety of battery use. Utility Model Content

[0004] Based on this, the present application provides a pole piece and a winding core to solve the problem in the related art that the positive electrode collector contacts the negative electrode coating or the negative electrode collector, causing the battery to catch fire, burn or explode, thereby improving the safety performance of the battery.

[0005] On the one hand, the present application provides a pole piece, including a current collector, an active material layer, a pole ear and a safety coating, wherein the active material layer is located on at least one side of the current collector surface, and the pole piece includes a double-sided area, a single-sided area and a hollow foil area, wherein the double-sided area is an area where the active material layer exists on both sides of the current collector, the single-sided area is an area where the active material layer exists on only one side of the current collector, and the hollow foil area is an area where the active material layer is not coated;

[0006] Wherein, the safety coating is arranged on the empty foil area, on the current collector surface, and the safety coating is connected to the active material layer located on the same side of the current collector surface;

[0007] The safety coating is provided with a first groove, and the pole ear is located in the first groove.

[0008] In a possible implementation, a safety coating is provided on the surface of the current collector in the single-sided region that is away from the active material layer, and / or

[0009] A safety coating is formed between the current collector and the active material layer in the double-sided area.

[0010] In a possible implementation, the safety coating is provided with a second groove, and along the first direction, the first groove is located on one side of the pole piece, and the second groove is located on the other side of the pole piece and is opposite to the first groove.

[0011] In a possible implementation manner, along the first direction, the width of the first groove is greater than the width of the second groove; and / or

[0012] Along the second direction, the length of the first groove is equal to the length of the second groove.

[0013] In a possible implementation, a first protective tape is provided on the pole piece, the first protective tape covers the first groove and the second groove, and along the first direction, the first protective tape extends out of at least one side in the width direction of the pole piece.

[0014] In a possible implementation, along the first direction, the width of the first protective tape extending out of the pole piece is smaller than the width of the second groove.

[0015] In one possible implementation, the safety coating is provided with a third groove and a fourth groove. Along the third direction, the first groove and the second groove are located on the same side of the pole piece, the third groove and the fourth groove are located on the other side of the pole piece, and the third groove is opposite to the first groove, and the fourth groove is opposite to the second groove.

[0016] In a possible implementation, a second protective tape is provided on the pole piece, the second protective tape covers the third groove and the fourth groove, and along the first direction, the second protective tape extends out of at least one side in the width direction of the pole piece.

[0017] In a possible implementation, along the first direction, the width of the second protective tape extending out of the pole piece is smaller than the width of the second groove.

[0018] In a possible implementation, along the third direction, the thickness of the weld mark between the electrode tab and the current collector is H, the thickness of the safety coating is T, and H and T satisfy: H>T.

[0019] On the other hand, the present application provides a winding core, including a second pole piece, a diaphragm and the above-mentioned pole piece, and the pole piece, the diaphragm and the second pole piece are stacked and wound in sequence.

[0020] In a possible implementation, a second pole lug is provided on the second pole piece, and in the thickness direction of the winding core, there is a gap between the orthographic projection of the safety coating in the empty foil area inside the winding core and the orthographic projection of the second pole lug; and / or

[0021] The pole tab is located on the outside of the winding core, and the pole tab is located on the side of the current collector facing the inside of the winding core.

[0022] The pole piece and winding core provided by the present application are provided with a safety coating on the surface of the current collector in the empty foil area, and the safety coating is connected to the active material layer, so as to cover the exposed current collector on the pole piece, and prevent the current collector of the pole piece from directly contacting the coating or current collector of another pole piece in the battery, thereby reducing the problem of fire and even explosion of the battery and improving the safety performance of the battery. In addition, a first groove for accommodating the pole ear is provided in the safety coating, so as to avoid the overlap of the safety coating and the pole ear, which leads to an increase in the thickness of the pole piece in the pole ear area, which is beneficial to improving the flatness of the obtained winding core and reducing the occurrence of interface gaps. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, a brief introduction will be given below to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0024] Figure 1 One of the structural schematic diagrams of the pole piece provided in the embodiment of the present application;

[0025] Figure 2 The second schematic diagram of the structure of the pole piece provided in the embodiment of the present application;

[0026] Figure 3 The third structural diagram of the pole piece provided in the embodiment of the present application;

[0027] Figure 4 A schematic diagram of the structure of the pole ear in the pole piece provided in an embodiment of the present application;

[0028] Figure 5 The fourth structural schematic diagram of the pole piece provided in the embodiment of the present application;

[0029] Figure 6 The fifth structural diagram of the pole piece provided in the embodiment of the present application;

[0030] Figure 7 The sixth structural diagram of the pole piece provided in the embodiment of the present application;

[0031] Figure 8 The seventh structural diagram of the pole piece provided in the embodiment of the present application;

[0032] Fig. 9 One of the structural schematic diagrams of the winding core provided in the embodiment of the present application;

[0033] Fig.10 This is the second structural schematic diagram of the winding core provided in the embodiment of the present application.

[0034] Description of reference numerals:

[0035] 100-pole piece; 101-double-sided area; 102-single-sided area; 103-empty foil area; 10-current collector; 20-active material layer; 30-pole ear; 31-weld stamp; 40-safety coating; 41-first groove; 42-second groove; 43-third groove; 44-fourth groove; 50-first protective tape; 60-second protective tape; 200-winding core; 201-second pole piece; 202-diaphragm; 203-second pole ear. DETAILED DESCRIPTION

[0036] In order to make the purpose, technical scheme and advantages of the present application clearer, the technical scheme in the embodiment of the present application will be described in more detail below in conjunction with the drawings in the preferred embodiments of the present application. In the drawings, the same or similar reference numerals throughout represent the same or similar parts or parts with the same or similar functions. The described embodiments are part of the embodiments of the present application, not all of the embodiments. The embodiments described below with reference to the drawings are exemplary and are intended to be used to explain the present application, and should not be construed as limitations on the present application. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present application. The embodiments of the present application are described in detail below in conjunction with the drawings.

[0037] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, or it can be an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0038] In the description of the present application, it should be understood that the terms "upper", "lower", "front", "back", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating orientations or positional relationships, are orientations or positional relationships based on the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0039] The terms "first", "second" and "third" (if any) in the specification and claims of this application and the above drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence.

[0040] In addition, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, for example, a process, method, system, product, or display comprising a series of steps or elements is not necessarily limited to those steps or elements explicitly listed, but may include other steps or elements not explicitly listed or inherent to such process, method, product, or display.

[0041] With the rapid development of battery technology, batteries have been widely used in various fields. The energy density, fast charging capability, and charge and discharge rate of batteries are constantly improving. At the same time, people's safety requirements for batteries are also getting higher and higher.

[0042] At present, some safety tests have found that in the battery, once the positive electrode collector comes into contact with the negative electrode coating or the negative electrode collector, it will release a large amount of energy in a very short time, causing the internal temperature of the battery to rise sharply, causing the battery to catch fire or even explode, seriously affecting the safety of battery use.

[0043] After repeated thinking and verification, the inventors found that if a shielding layer is coated on the surface of the current collector and a groove for accommodating the pole ear can be provided in the shielding layer, it can avoid overlapping of the shielding layer and the pole ear, so that the current collector of the pole piece cannot directly contact the coating or current collector of another pole piece, thereby reducing the problem of fire or even explosion of the battery and improving the safety performance of the battery.

[0044] In view of this, the utility model provides a pole piece, including a current collector, an active material layer, a pole ear and a safety coating, the active material layer is located on at least one side of the current collector surface, the pole piece includes a double-sided area, a single-sided area and a hollow foil area, the double-sided area is an area where the active material layer exists on both sides of the current collector, the single-sided area is an area where the active material layer exists on only one side of the current collector, and the hollow foil area is an area where the active material layer is not coated; wherein, the safety coating is arranged on the current collector surface in the hollow foil area, and the safety coating is connected to the active material layer located on the same side of the current collector surface; the safety coating is provided with a first groove, and the pole ear is located in the first groove.

[0045] By arranging a safety coating on the surface of the current collector in the empty foil area and connecting the safety coating with the active material layer, the exposed current collector on the pole piece is covered to prevent the current collector of the pole piece from directly contacting the coating or current collector of another pole piece in the battery, thereby reducing the problem of fire or even explosion of the battery and improving the safety performance of the battery. In addition, a first groove for accommodating the pole ear is arranged in the safety coating to avoid overlapping of the safety coating with the pole ear, which leads to an increase in the thickness of the pole piece in the pole ear area, and is beneficial to improving the flatness of the obtained winding core and reducing the occurrence of interface gaps.

[0046] The content of the utility model will be described in detail below with reference to the accompanying drawings so that those skilled in the art can understand the content of the utility model more clearly and in detail.

[0047] Figure 1 This is one of the schematic diagrams of the structure of the pole piece provided in the embodiment of the present application. Figure 2 This is the second schematic diagram of the structure of the pole piece provided in the embodiment of the present application. Figure 3 This is the third structural schematic diagram of the pole piece provided in the embodiment of the present application. Figure 4 This is a schematic diagram of the structure of the pole ear in the pole piece provided in an embodiment of the present application. Figure 5 This is the fourth schematic diagram of the structure of the pole piece provided in the embodiment of the present application. Figure 6 This is the fifth structural schematic diagram of the pole piece provided in the embodiment of the present application. Figure 7 This is the sixth structural schematic diagram of the pole piece provided in the embodiment of the present application. Figure 8 This is the seventh structural schematic diagram of the pole piece provided in the embodiment of the present application. Fig. 9 This is one of the structural schematic diagrams of the winding core provided in an embodiment of the present application. Fig.10 This is the second structural schematic diagram of the winding core provided in the embodiment of the present application.

[0048] like Figure 1 As shown, the embodiment of the present application provides a pole piece 100, including a current collector 10, an active material layer 20, a pole ear 30 and a safety coating 40. The active material layer 20 is located on at least one side of the surface of the current collector 10. The pole ear 30 is electrically connected to the current collector 10. The safety coating 40 is located on the surface of the current collector 10.

[0049] Specifically, along the thickness direction of the pole piece 100, the active material layer 20 is coated on the surface of both sides of the current collector 10. And along the length direction of the pole piece 100, on the two surfaces of the current collector 10, the lengths of the two active material layers 20 are different. Therefore, the pole piece 100 includes a double-sided area 101, a single-sided area 102 and an empty foil area 103. Among them, the double-sided area 101 is an area where the active material layer 20 exists on both sides of the current collector 10, the single-sided area 102 is an area where the active material layer 20 exists on only one side of the current collector 10, and the empty foil area 103 is an area where only the current collector 10 exists, that is, an area where the active material layer 20 is not coated.

[0050] like Figure 1 and Figure 2 As shown, the first direction A is the width direction of the pole piece 100 , the second direction B is the length direction of the pole piece 100 , and the third direction C is the thickness direction of the pole piece 100 .

[0051] In the embodiment of the present application, one side of the pole piece 100 in the length direction, that is, one side in the second direction B, is recorded as the head of the pole piece 100, and the other side of the pole piece 100 in the length direction, that is, the other side in the second direction B, is recorded as the tail of the pole piece 100. In the winding core, the pole piece 100 is wound from the head to the tail along the length direction of the pole piece 100.

[0052] Along the length direction of the pole piece 100, i.e., the second direction B, the empty foil area 103 is provided at both ends of the pole piece 100. In the embodiment of the present application, along the length direction of the pole piece 100, i.e., the second direction B, the pole piece 100 includes an empty foil area 103, a double-sided area 101, a single-sided area 102 and an empty foil area 103 connected in sequence.

[0053] The electrode tab 30 is connected to the current collector 10 in the empty foil area 103 by welding.

[0054] In the embodiment of the present application, in the empty foil area 103 at the head of the pole piece 100 , the pole tab 30 is connected to the current collector 10 by welding.

[0055] The safety coating 40 is arranged on the empty foil area 103, and / or the surface of the current collector 10 in the single-sided area 102, that is, the safety coating 40 can be arranged on both surfaces of the current collector 10 in the empty foil area 103 at the head of the pole piece 100, or on both surfaces of the current collector 10 in the empty foil area 103 at the tail of the pole piece 100, or on the surface of the current collector 10 in the single-sided area 102 where the active material layer 20 is not arranged, that is, the surface of the current collector 10 facing away from the active material layer 20.

[0056] In the embodiment of the present application, the safety coating 40 is disposed on the surface of the current collector 10 in both the empty foil area 103 and the single-sided area 102 .

[0057] The safety coating layer 40 is connected to the active material layer 20. That is, the safety coating layer 40 is connected to the active material layer 20 on the surface of the current collector 10 on the same side.

[0058] It can be understood that the connection between the safety coating 40 and the active material layer 20 can be achieved by covering, that is, the active material layer 20 covers part of the safety coating 40, so that in the double-sided area 101, the safety coating 40 is formed between the current collector 10 and the active material layer 20.

[0059] In the embodiment of the present application, the safety coating 40 of the empty foil area 103 at the head of the pole piece 100 is connected to the active material layer 20 of the double-sided area 101 of the pole piece 100; the safety coating 40 of the empty foil area 103 at the tail of the pole piece 100 is connected to the active material layer 20 of the single-sided area 102 of the pole piece 100; the safety coating 40 of the single-sided area 102 of the pole piece 100 is connected to the active material layer 20 of the double-sided area 101 of the pole piece 100.

[0060] The safety coating 40 has a certain insulating property, thereby preventing the current collector 10 on the pole piece 100 from contacting the negative electrode or the negative electrode current collector.

[0061] Please also see Figure 2 In a possible implementation, the safety coating 40 is provided with a first groove 41 , and the pole ear 30 is located in the first groove 41 .

[0062] Specifically, in the embodiment of the present application, on the safety coating 40 on the surface of the current collector 10 on one side of the empty foil area 103 at the head of the pole piece 100, along the length direction of the pole piece 100, that is, the second direction B, a first groove 41 is provided in the middle of the safety coating 40, and the pole ear 30 is provided in the first groove 41 and welded to the current collector 10 at the bottom of the first groove 41. The pole ear 30 extends out of the first groove 41 along the width direction of the pole piece 100, that is, the first direction A, and thus extends out of the current collector 10.

[0063] By providing the first groove 41 in the safety coating 40 and placing the pole lug 30 in the first groove 41, it is possible to avoid the safety coating 40 and the pole lug 30 from overlapping, thereby preventing the thickness of the pole lug region in the pole piece 100 from increasing, thereby improving the flatness of the winding core and reducing the appearance of the interface gap. It can also prevent the problem of low battery energy density caused by increased battery thickness.

[0064] In a possible implementation, the safety coating 40 is provided with a second groove 42 , and the second groove 42 and the first groove 41 are located on the same safety coating 40 .

[0065] Specifically, a first groove 41 and a second groove 42 are provided on the safety coating 40 on one side of the current collector 10 at the empty foil area 103 at the head of the pole piece 100. In addition, along the width direction of the pole piece 100, that is, the first direction A, the first groove 41 is located on one side of the pole piece 100, and the second groove 42 is located on the other side of the pole piece 100 and is opposite to the first groove 41.

[0066] By providing the second groove 42 opposite to the first groove 41 in the safety coating 40, the slitting tolerance of the pole piece 100 during the slitting process can be avoided. Since the pole piece 100 is obtained by slitting a large roll of material along the length direction of the pole piece 100, there will inevitably be a slitting tolerance along the width direction of the pole piece 100. Therefore, considering the slitting tolerance, the second groove 42 is provided on the other side of the safety coating 40 opposite to the first groove 41 in the width direction of the pole piece 100.

[0067] Along the width direction of the pole piece 100 , ie, the first direction A, the width of the first groove 41 is L1 , and the width of the second groove 42 is L2 ; along the length direction of the pole piece 100 , ie, the second direction B, the length of the first groove 41 is W1 , and the length of the second groove 42 is W2 .

[0068] In a possible implementation, a width L1 of the first groove 41 is greater than a width L2 of the second groove 42 .

[0069] Since the second groove 42 is provided to eliminate the slitting tolerance, the width L2 of the second groove 42 should be relatively small in order to better cover the current collector 10 and prevent the current collector 10 from contacting the negative electrode or the negative electrode current collector.

[0070] In a possible implementation, the length W1 of the first groove 41 is equal to the length W2 of the second groove 42 .

[0071] Since the pole piece 100 is obtained by cutting a large roll of material along the length direction of the pole piece 100, in order to facilitate processing, a groove is directly set on the large roll of material, and then the groove is cut into a first groove 41 and a second groove 42 during cutting. Therefore, the length W1 of the first groove 41 is equal to the length W2 of the second groove 42.

[0072] like Figure 3 As shown, in a possible implementation, the safety coating 40 is further provided with a third groove 43 and a fourth groove 44. The third groove 43 and the fourth groove 44 are located on another safety coating 40 opposite to the safety coating 40 where the first groove 41 is located.

[0073] Specifically, along the thickness direction of the pole piece 100, that is, the third direction C, the first groove 41 and the second groove 42 are located on the same surface of the pole piece 100, that is, they are located on the safety coating 40 on one side of the surface of the current collector 10 in the empty foil area 103 at the head of the pole piece 100, and the third groove 43 and the fourth groove 44 are located on the other side of the pole piece 100, that is, they are located on the safety coating 40 on the other side of the surface of the current collector 10 in the empty foil area 103 at the head of the pole piece 100, and the third groove 43 is opposite to the first groove 41, and the fourth groove 44 is opposite to the second groove 42.

[0074] Since the pole tab 30 is welded on the current collector 10, the thickness of the pole piece 100 in the pole tab welding area becomes thicker. At the position corresponding to the position where the pole tab 30 is set on the pole piece 100, the first groove 41 and the second groove 42, the third groove 43 and the fourth groove 44 are respectively set in the safety coating 40 on both sides of the current collector 10 at this position, so that the pole tab welding area can be prevented from being too thick, which is beneficial to improving the flatness of the obtained winding core and reducing the appearance of the interface gap. And it can prevent the problem of low battery energy density caused by the increase of battery thickness.

[0075] like Figure 4 As shown, in a possible implementation, along the thickness direction of the electrode sheet 100 , that is, the third direction C, a welding mark 31 is formed on the surface of the electrode tab 30 after the electrode tab 30 is welded to the current collector 10 .

[0076] Along the thickness direction of the pole piece 100 , that is, the third direction C, the thickness of the weld mark 31 is H, and the thickness of the safety coating 40 is T. H and T satisfy: H>T.

[0077] Since the function of the safety coating 40 is only to cover the current collector 10 and prevent the current collector 10 from directly contacting the negative electrode coating or the negative electrode current collector, in order to prevent the safety coating 40 from wasting the internal space of the battery and improve the battery energy density, the safety coating 40 should be as thin as possible.

[0078] like Figure 5As shown, in a possible implementation, a first protective adhesive tape 50 is disposed on the pole piece 100. The first protective adhesive tape 50 is disposed on the surface of the pole ear 30 away from the current collector 10.

[0079] The first protective tape 50 is used to prevent the welding mark 31 on the electrode tab 30 from piercing the separator in the battery, thereby reducing the contact between the electrode tab 30 and the second electrode sheet, which may cause a short circuit.

[0080] Specifically, along the length direction of the pole piece 100, that is, the second direction B, the first protective tape 50 covers the first groove 41 and the second groove 42. Along the width direction of the pole piece 100, that is, the first direction A, the first protective tape 50 extends out of at least one side of the width direction of the pole piece 100.

[0081] The first protective tape 50 exceeds the width of the pole piece 100 to prevent the cross-sectional burrs generated along the edge of the pole piece 100 in the width direction from piercing the diaphragm in the battery when the pole piece is cut, causing the pole piece 100 to contact with the second pole piece and cause a short circuit.

[0082] In a possible implementation, along the width direction of the pole piece 100 , that is, the first direction A, the width of the first protective tape 50 extending out of the pole piece 100 is smaller than the width of the second groove 42 .

[0083] Since the first protective tape 50 is only used to prevent puncture, in order to prevent the first protective tape 50 from being too long and affecting the height of the final winding core, the first protective tape 50 should not exceed the distance too long.

[0084] like Figure 6 As shown, in a possible implementation, a second protective adhesive tape 60 is further disposed on the pole piece 100 . The second protective adhesive tape 60 is disposed on another surface of the pole piece 100 opposite to the first protective adhesive tape 50 .

[0085] The second protective tape 60 is also used to prevent the welding mark 31 after welding the pole tab 30 from piercing the separator in the battery, thereby reducing the contact between the pole tab 30 and the second pole piece, which may cause a short circuit.

[0086] Specifically, along the length direction of the pole piece 100, that is, the second direction B, the second protective tape 60 covers the third groove 43 and the fourth groove 44. Along the width direction of the pole piece 100, that is, the first direction A, the second protective tape 60 extends out of at least one side of the width direction of the pole piece 100.

[0087] The second protective tape 60 exceeds the width of the pole piece 100 to prevent the cross-sectional burrs generated along the edge of the pole piece 100 in the width direction from piercing the diaphragm in the battery when the pole piece is cut, causing the pole piece 100 to contact with the second pole piece and cause a short circuit.

[0088] In a possible implementation, along the width direction of the pole piece 100 , that is, the first direction A, the width of the second protective tape 60 extending out of the pole piece 100 is smaller than the width of the second groove 42 .

[0089] Since the second protective tape 60 is only used to prevent puncture, in order to prevent the second protective tape 60 from being too long and affecting the height of the final winding core, the second protective tape 60 should not exceed the distance too long.

[0090] like Figure 7 As shown, in a possible implementation, along the length direction of the electrode piece 100 , that is, the second direction B, the first protective adhesive tape 50 extends along the length direction of the electrode piece 100 and covers the edge of the active material layer 20 .

[0091] During the core winding process, the empty foil area 103 at the head of the electrode 100 to the edge of the double-sided area 101 connected thereto is the part that is bent when the head is wound, in order to reduce the complexity of gluing in this area, the length of the first protective adhesive tape 50 is set to be longer, so that the welding position of the electrode ear 30, the first groove 41, the second groove 42 and the active material layer 20 at the edge of the head double-sided area 101 can be covered by a piece of the first protective adhesive tape 50, which simplifies the structure of the core winding, allows for quick gluing of the electrode 100, and improves production efficiency.

[0092] like Figure 8 As shown, in a possible implementation, along the length direction of the electrode piece 100 , that is, the second direction B, the second protective tape 60 extends along the length direction of the electrode piece 100 and covers the edge of the active material layer 20 .

[0093] During the core winding process, the empty foil area 103 at the head of the electrode 100 to the edge of the double-sided area 101 connected thereto is the part that is bent when the head is wound, in order to reduce the complexity of gluing in this area, the length of the second protective adhesive tape 60 is set to be longer, so that the welding position of the electrode ear 30, the third groove 43, the fourth groove 44 and the active material layer 20 at the edge of the head double-sided area 101 can be covered by a piece of second protective adhesive tape 60, which simplifies the structure of the core winding, allows for quick gluing of the electrode 100, and improves production efficiency.

[0094] In a possible implementation, the safety coating 40 includes an inorganic filler, a conductive agent, and a binder.

[0095] Specifically, the inorganic filler is selected from one or more of lithium cobalt oxide (LCO), nickel cobalt manganese ternary material (NCM), nickel cobalt aluminum ternary material (NCA), nickel cobalt manganese aluminum quaternary material (NCMA), lithium iron phosphate (LFP), carbon-coated lithium iron phosphate (C-LFP), lithium manganese phosphate (LMP), lithium manganese oxide (LMO), and lithium-rich manganese-based; or

[0096] The inorganic filler is selected from ceramic materials, and specifically can be selected from one or more ceramic materials such as alumina, boehmite, magnesium oxide, magnesium hydroxide, etc.; or

[0097] The inorganic filler is selected from a mixture of at least one of lithium-containing transition metal oxides and at least one of ceramic materials.

[0098] The conductive agent is selected from one or more of conductive carbon black, acetylene black, conductive graphite, Ketjen black, carbon nanotubes and graphene;

[0099] The binder is selected from one or more of polyvinylidene fluoride, polytetrafluoroethylene, polyvinyl pyrrolidone, polyacrylic acid, polyacrylonitrile, lithium polyacrylate, polyamide, methacrylate, and sodium carboxymethyl cellulose.

[0100] The pole piece 100 provided in the embodiment of the present application includes a current collector 10, an active material layer 20, a pole ear 30 and a safety coating 40. The active material layer 20 is located on at least one side of the surface of the current collector 10. The pole piece 100 includes a double-sided area 101, a single-sided area 102 and a hollow foil area 103. The double-sided area 101 is an area where the active material layer 20 exists on both sides of the current collector 10, the single-sided area 102 is an area where the active material layer 20 exists on only one side of the current collector 10, and the hollow foil area 103 is an area where the active material layer 20 is not coated; wherein the safety coating 40 is arranged on the surface of the current collector 10 in the hollow foil area 103, and the safety coating 40 is connected to the active material layer 20 located on the same side of the surface of the current collector 10; the safety coating 40 is provided with a first groove 41, and the pole ear 30 is located in the first groove 41.

[0101] By setting a safety coating 40 on the surface of the current collector 10 in the empty foil area 103 and connecting the safety coating 40 with the active material layer 20, the exposed current collector 10 on the pole piece 100 is covered to prevent the current collector 10 of the pole piece 100 from directly contacting the coating or current collector of another pole piece in the battery, thereby reducing the problem of fire or even explosion of the battery and improving the safety performance of the battery. In addition, a first groove 41 for accommodating the pole ear 30 is provided in the safety coating 40 to avoid overlapping of the safety coating 40 with the pole ear 30, which leads to an increase in the thickness of the pole piece 100 in the pole ear 30 area, which is beneficial to improving the flatness of the obtained winding core and reducing the occurrence of interface gaps.

[0102] In addition, if Fig. 9 and Fig.10 As shown, the embodiment of the present application further provides a winding core 200, comprising a second pole piece 201, a diaphragm 202 and the pole piece 100. The pole piece 100, the diaphragm 202 and the second pole piece 201 are stacked and wound in sequence. A second pole ear 203 is provided on the second pole piece 201.

[0103] Exemplarily, the electrode sheet 100 may be a positive electrode sheet, and the second electrode sheet 201 may be a negative electrode sheet; or, the electrode sheet 100 may be a negative electrode sheet, and the second electrode sheet 201 may be a positive electrode sheet, which is not limited here.

[0104] like Fig. 9 As shown, in a possible implementation, the pole ear 30 is located at the head of the pole piece 100 , and during winding, the pole ear 30 is rolled into the middle of the winding core 200 .

[0105] In the thickness direction of the winding core 200 , there is a gap between the orthographic projection of the security coating 40 in the empty foil area 103 inside the winding core 200 and the orthographic projection of the second electrode tab 203 .

[0106] like Fig. 9 As shown, the fourth direction D is the thickness direction of the winding core 200 .

[0107] Due to the setting of the second pole ear 203, the thickness of the core 200 at this position is relatively thick. The setting area of ​​the safety coating 40 is set in the thickness direction of the core 200, that is, the fourth direction D, so as not to overlap with the second pole ear 203. This can prevent the thickness of the core 200 from increasing, thereby improving the energy density of the battery.

[0108] like Fig.10 As shown, in another possible implementation, the pole ear 30 is located at the tail of the pole piece 100 , and when winding, the pole ear 30 is located outside the winding core 200 .

[0109] Specifically, the tab 30 is located on a side of the current collector 10 that faces the inner side of the winding core 200 .

[0110] The tab 30 is arranged on the side of the current collector 10 facing the inner side of the winding core 200 , which can reduce the protrusion of the weld mark 31 when the tab 30 is welded, resulting in a protruding stamp formed on the surface of the winding core, thereby improving the flatness of the winding core 200 .

[0111] The winding core 200 provided in the embodiment of the present application provides a safety coating 40 on the surface of the current collector 10 in the empty foil area 103, and connects the safety coating 40 to the active material layer 20, thereby covering the exposed current collector 10 on the pole piece 100, preventing the current collector 10 of the pole piece 100 from directly contacting the coating or current collector of the second pole piece 201 in the battery, reducing the problem of fire or even explosion of the battery, and improving the safety performance of the battery. In addition, a first groove 41 for accommodating the pole ear 30 is provided in the safety coating 40, which avoids the overlap of the safety coating 40 and the pole ear 30, resulting in an increase in the thickness of the pole piece 100 in the pole ear 30 area, which is beneficial to improving the flatness of the winding core 200 and reducing the occurrence of interface gaps.

[0112] The embodiment of the present application further provides a battery, comprising a battery housing and the above-mentioned winding core 200. The winding core 200 is located in the battery housing.

[0113] The battery is not limited to lithium batteries, and in the future this technology may be applied to sodium batteries, etc. In the present application, lithium-ion batteries are preferred.

[0114] Among them, the specific structure, working principle and function of the winding core 200 have been described in detail in the above embodiments and will not be repeated here.

[0115] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit it. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A pole piece (100), characterized in that: The present invention comprises a current collector (10), an active material layer (20), a pole ear (30) and a safety coating (40), wherein the active material layer (20) is located on at least one side of the surface of the current collector (10), and the pole piece (100) comprises a double-sided area (101), a single-sided area (102) and a hollow foil area (103), wherein the double-sided area (101) is an area where the active material layer (20) exists on both sides of the current collector (10), the single-sided area (102) is an area where the active material layer (20) exists on only one side of the current collector (10), and the hollow foil area (103) is an area where the active material layer (20) is not coated; The safety coating (40) is disposed on the surface of the current collector (10) in the empty foil area (103), and the safety coating (40) is connected to the active material layer (20) located on the same side of the surface of the current collector (10); The safety coating (40) is provided with a first groove (41), and the pole lug (30) is located in the first groove (41).

2. The pole piece (100) according to claim 1, characterized in that: The safety coating (40) is provided on the surface of the current collector (10) of the single-sided area (102) facing away from the active material layer (20), and / or The safety coating (40) is formed between the current collector and the active material layer (20) in the double-sided area.

3. The pole piece (100) according to claim 1, characterized in that: The safety coating (40) is provided with a second groove (42); along a first direction, the first groove (41) is located on one side of the pole piece (100), and the second groove (42) is located on the other side of the pole piece (100) and is opposite to the first groove (41).

4. The pole piece (100) according to claim 3, characterized in that: Along a first direction, the width of the first groove (41) is greater than the width of the second groove (42); and / or Along the second direction, the length of the first groove (41) is equal to the length of the second groove (42).

5. The pole piece (100) according to claim 3, characterized in that: A first protective tape (50) is provided on the pole piece (100), the first protective tape (50) covers the first groove (41) and the second groove (42), and along a first direction, the first protective tape (50) extends out of at least one side of the width direction of the pole piece (100).

6. The pole piece (100) according to claim 5, characterized in that: Along the first direction, the width of the first protective tape (50) extending out of the pole piece (100) is smaller than the width of the second groove (42).

7. The pole piece (100) according to claim 3, characterized in that: The safety coating (40) is provided with a third groove (43) and a fourth groove (44); along a third direction, the first groove (41) and the second groove (42) are located on the same surface of the pole piece (100); the third groove (43) and the fourth groove (44) are located on the other surface of the pole piece (100); and the third groove (43) is opposite to the first groove (41), and the fourth groove (44) is opposite to the second groove (42).

8. The pole piece (100) according to claim 7, characterized in that: A second protective tape (60) is provided on the pole piece (100), the second protective tape (60) covers the third groove (43) and the fourth groove (44), and along the first direction, the second protective tape (60) extends out of at least one side of the width direction of the pole piece (100).

9. The pole piece (100) according to claim 8, characterized in that: Along the first direction, the width of the second protective tape (60) extending out of the pole piece (100) is smaller than the width of the second groove (42).

10. The pole piece (100) according to claim 1, characterized in that: Along the third direction, the thickness of the weld mark (31) of the electrode tab (30) and the current collector (10) is H, the thickness of the safety coating (40) is T, and H and T satisfy: H>T.

11. A winding core (200), characterized in that: It comprises a second pole piece (201), a diaphragm (202), and a pole piece (100) according to any one of claims 1 to 10, wherein the pole piece (100), the diaphragm (202), and the second pole piece (201) are sequentially stacked and wound.

12. The winding core (200) according to claim 11, characterized in that: A second pole lug (203) is provided on the second pole piece (201), and in the thickness direction of the winding core (200), there is a distance between the orthographic projection of the safety coating (40) in the empty foil area (103) located inside the winding core (200) and the orthographic projection of the second pole lug (203); and / or The pole lug (30) is located outside the winding core (200), and the pole lug (30) is located on a side of the current collector (10) facing the inside of the winding core (200).

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