Pole piece, roll core, electric device and manufacturing method of roll core

Abstract

The invention belongs to the technical field of power batteries, and discloses a pole piece, a roll core, an electric device and a manufacturing method of the roll core. The pole piece comprises a pole piece main body and an insulating part, the pole piece main body comprises a current collector and an active substance layer coated on at least one surface of the current collector, and the pole piece main body comprises a winding head end and a winding tail end which are oppositely arranged along a first direction; the insulating parts cover a part of the active material layer of the winding head end and / or the winding tail end along the second direction, in the winding head end and / or the winding tail end, one end of at least one insulating part along the first direction coincides with the edge of the pole piece main body along the first direction, or at least one insulating part exceeds the edge of the pole piece main body along the first direction along the first direction; the first direction is perpendicular to the second direction. And the exposed size of the active material layer along the second direction is reduced by utilizing the insulating part, so that the A-C overhang of the positive pole piece and the negative pole piece is favorably increased, the bad influence of drifting is reduced, the internal short circuit is favorably avoided, and the use safety of the power battery is ensured.

Description

Technical Field

[0001] The present invention relates to the technical field of power batteries, and in particular to a pole piece, a winding core, an electrical device, and a method for manufacturing the winding core. Background Art

[0002] The production process of lithium battery cells usually includes electrode manufacturing, assembly process and cell testing. The winding process is one of the key links in the assembly process. The specific method is to wind and extrude the positive electrode sheets, diaphragms and negative electrode sheets that have been processed in the early stage in sequence through the winding of a fixed winding needle.

[0003] During the actual winding process, the positive and negative electrode sheets exhibit dimensional differences along the core axis at the beginning and end of the winding process, also known as AC overhang. This design ensures that the negative electrode sheet exceeds the positive electrode sheet along the core axis, avoiding safety hazards and performance degradation caused by exposed electrode edges.

[0004] Since there is no traction tension at the tail and head ends of the cut-off positive and negative electrode sheets during winding, the positions of the positive and negative electrode sheets at the head and tail ends of the winding are offset, that is, the problem of poor winding tail swing occurs, which reduces the AC Overhang (OH) and easily causes the burrs of the positive electrode sheet to contact the negative electrode sheet, causing internal short circuit problems, which can easily cause battery cell safety risks. Summary of the Invention

[0005] The object of the present invention is to provide a pole piece, a winding core, an electrical device and a method for preparing the winding core, which can solve the problem of poor winding tail swinging resulting in reduced AC overhang and easy internal short circuit.

[0006] To achieve this object, the present invention adopts the following technical solutions:

[0007] A pole piece, comprising:

[0008] A pole piece body, the pole piece body comprising a current collector and an active material layer coated on at least one surface of the current collector, the pole piece body comprising a winding head end and a winding tail end oppositely disposed along a first direction;

[0009] An insulating member covers a portion of the active material layer along the second direction at the winding head end and / or the winding tail end, wherein at least one end of the insulating member along the first direction coincides with the edge of the pole piece body along the first direction, or at least one insulating member extends beyond the edge of the pole piece body along the first direction along the first direction, and the first direction is perpendicular to the second direction.

[0010] As an optional solution to the above-mentioned pole piece, the pole piece body includes:

[0011] a first covering area and a second covering area located at the winding head end, wherein the first covering area and the second covering area are arranged at two ends of the winding head end along the second direction;

[0012] a third covering area and a fourth covering area located at the winding tail end, wherein the third covering area and the fourth covering area are located at two ends of the winding tail end along the second direction;

[0013] Among them, the first covering area and the third covering area are located at the two ends of the pole piece body along the first direction, the second covering area and the fourth covering area are located at the two ends of the pole piece body along the first direction, and the first covering area, the second covering area, the third covering area and the fourth covering area are all provided with the insulating part.

[0014] As an optional solution for the above-mentioned pole piece, the pole piece body includes a first covering area located at the beginning of the winding and a second covering area located at the end of the winding, the first covering area and the second covering area are located on the same side of the pole piece body along the second direction, and the first covering area and the second covering area are both provided with insulating parts.

[0015] As an optional solution for the above-mentioned pole piece, the pole piece body includes a first covering area located at the beginning of the winding and a second covering area located at the end of the winding, the first covering area and the second covering area are respectively located on both sides of the pole piece body along the second direction, and the first covering area and the second covering area are both provided with insulating parts.

[0016] As an optional solution of the above-mentioned electrode sheet, the electrode sheet body further includes a pole ear and an insulating coating, the current collector includes a first end and a second end arranged opposite to each other along the second direction, the first end is connected to the pole ear, and at least a portion of the insulating coating is located between the pole ear and the active material layer;

[0017] The insulating member covering the first end includes a first insulating portion and a second insulating portion, the first insulating portion covers at least a portion of the insulating coating layer, and the second insulating portion covers a portion of the active material layer;

[0018] Alternatively, the insulating member covering the first end only covers the active material layer.

[0019] As an optional solution of the above-mentioned pole piece, the insulating member includes a first edge, a second edge, a third edge and a fourth edge connected in sequence, wherein the first edge is parallel to the edge of the pole piece body along the first direction, and the second edge is parallel to the edge of the pole piece body along the second direction;

[0020] Along the second direction, the distance between the third edge and the first edge remains constant, or the distance between the third edge and the first edge changes gradually.

[0021] As an optional solution of the above-mentioned pole piece, the insulating member is a rectangular film layer, and the size of the insulating member along the first direction is 100-500 mm;

[0022] And / or, a dimension of the first insulating portion along the second direction is 0.5-5 mm;

[0023] And / or, a dimension of the second insulating portion along the second direction is 0.5-20 mm.

[0024] As an optional solution for the above-mentioned pole piece, the insulating member is a trapezoidal film layer, which is located in the insulating member at the winding head end, and the size of the second insulating portion gradually decreases along the second direction from the winding head end to the winding tail end;

[0025] In the insulating member located at the winding tail end, along the direction from the winding head end to the winding tail end, the size of the second insulating portion along the second direction gradually increases.

[0026] As an optional solution of the above-mentioned pole piece, the size of the insulating member along the first direction is 100-500 mm;

[0027] And / or, a dimension of the first insulating portion along the second direction is 0.5-5 mm;

[0028] And / or, the maximum dimension of the second insulating portion along the second direction is less than or equal to 20 mm, and the minimum dimension of the second insulating portion along the second direction is greater than or equal to 0.5 mm.

[0029] As an optional solution of the above-mentioned pole piece, the pole piece body further includes a pole ear, the current collector includes a first end and a second end oppositely arranged along the second direction, and the first end is connected to the pole ear;

[0030] The insulating member covering the second end includes a third insulating portion and a fourth insulating portion, the third insulating portion covers a portion of the active material layer, and the fourth insulating portion extends out of the current collector along the second direction;

[0031] Alternatively, the insulating member covering the second end only covers the active material layer.

[0032] As an optional solution to the above-mentioned pole piece, the size of the fourth insulating portion along the second direction is 0-2 mm.

[0033] As an optional solution to the above-mentioned pole piece, the insulating member is a tape.

[0034] As an optional solution to the above-mentioned pole piece, the insulating member and the active material layer have different colors.

[0035] As an optional solution for the above-mentioned pole piece, the active material layer is provided on both sides of the current collector in the thickness direction, and the insulating members on the active material layers on both sides are correspondingly provided.

[0036] As an optional solution for the above-mentioned pole piece, a marking portion is provided on the pole piece body.

[0037] As an optional solution to the above-mentioned electrode, the marking portion is a marking hole;

[0038] Alternatively, the marking portion is a marking mark;

[0039] Alternatively, the color of the marking portion is different from the color of the electrode body where it is located.

[0040] As an optional solution for the above-mentioned pole piece, the pole piece body also includes a pole ear, and the pole ear is connected to the side edge of the current collector along the second direction. Multiple pole ears are arranged along the first direction, and the marking portion is arranged on the first pole ear in the direction from the winding head end to the winding tail end.

[0041] A winding core comprises a stacked positive electrode sheet, a separator and a negative electrode sheet, wherein the positive electrode sheet is the above-mentioned sheet, and the second direction is the axial direction of the winding core.

[0042] As an optional solution for the above-mentioned winding core, the negative electrode sheet includes a fifth edge and a sixth edge arranged opposite to each other along the second direction, the insulating member includes a first edge and a third edge arranged opposite to each other along the second direction, the third edge is located on the active material layer, and the projection of the fifth edge along the stacking direction is located on the side of the first edge away from the third edge.

[0043] As an optional solution for the above-mentioned winding core, the negative electrode sheet includes a fifth edge and a sixth edge arranged opposite to each other along the second direction, the insulating member includes a first edge and a third edge arranged opposite to each other along the second direction, the third edge is located on the active material layer, and the projection of the fifth edge along the stacking direction coincides with the first edge.

[0044] As an optional solution for the above-mentioned winding core, the negative electrode sheet includes a fifth edge and a sixth edge arranged opposite to each other along the second direction, the insulating member includes a first edge and a third edge arranged opposite to each other along the second direction, the third edge is located on the active material layer, and the projection of the fifth edge along the stacking direction is respectively located between the first edge and the third edge.

[0045] As an optional solution of the above-mentioned winding core, the fifth edge and the third edge have a distance OH1 along the second direction, and the sixth edge and the third edge have a distance OH2 along the second direction, wherein OH1 is greater than or equal to OH2.

[0046] As an optional solution for the above-mentioned core, 1.5mm≤OH1≤21mm;

[0047] and / or, 1.3mm≤OH2≤21mm.

[0048] As an optional solution for the above-mentioned winding core, 0≤OH1-OH2≤2mm.

[0049] An electrical device comprises the winding core mentioned above.

[0050] A method for manufacturing a winding core, used to manufacture the above-mentioned winding core, the method for manufacturing the winding core comprising:

[0051] Prepare a positive electrode sheet, so that the active material layer at the winding head end and / or the winding tail end of the positive electrode sheet is covered with an insulating member;

[0052] The negative electrode sheet, the separator and the positive electrode sheet are stacked in sequence and wound into a winding core along the second direction as the axis.

[0053] As an optional solution to the above-mentioned method for manufacturing the winding core, preparing the positive electrode sheet includes:

[0054] Unwinding the pole piece coil;

[0055] Identify the marking portion on the electrode sheet coil to obtain the position of the attachment position d and the position of the cutting line c on the electrode sheet coil, wherein a portion of the cutting line c is located within the attachment position d;

[0056] Attaching an insulating layer to the attachment position d;

[0057] The electrode sheet coil and the insulating layer are cut along the cutting line c to obtain the positive electrode sheet with the insulating member attached to the winding head end and / or the winding tail end.

[0058] As an optional solution to the above-mentioned method for manufacturing the winding core, preparing the positive electrode sheet includes:

[0059] Unwinding the pole piece coil;

[0060] Identify the marking portion on the electrode sheet coil to obtain the position of the cutting line c on the electrode sheet coil;

[0061] Cutting the electrode coil along the cutting line c to obtain the electrode body;

[0062] The insulating member is attached to the winding head end and / or the winding tail end of the pole piece body.

[0063] As an optional solution to the above-mentioned method for manufacturing the winding core, the method for manufacturing the winding core further includes:

[0064] The edges of the tab side and the non-tab side of the winding core are identified to detect whether the size difference between the positive electrode sheet and the negative electrode sheet is within a preset range.

[0065] Beneficial effects of the present invention:

[0066] In the pole piece provided by the present invention, an insulating member is used to cover a portion of the active material layer of at least one of the winding head end and the winding tail end of the pole piece body, which can reduce the exposed size of the active material layer along the second direction, thereby facilitating the increase of the AC Overhang of the positive pole piece and the negative pole piece in the winding core, reducing the influence of poor tail swing on the AC Overhang, and avoiding the A-C Overhang from deviating from the center value, thereby facilitating the avoidance of internal short circuit and ensuring safe use.

[0067] The insulating part includes a first insulating part and a second insulating part. The first insulating part covers at least a portion of the insulating coating, and the second insulating part covers a portion of the active material layer, so that the insulating part can completely cover the edge of the active material layer along the second direction, thereby preventing the CCD camera from capturing the edge of the active material layer along the second direction during edge detection, and avoiding the problem of false alarms during edge detection.

[0068] The winding core provided by the present invention adopts the above-mentioned electrode sheet as the positive electrode sheet, which can effectively increase the AC Overhang of the positive electrode sheet and the negative electrode sheet, reduce the impact of poor tail swing on the AC Overhang, and prevent the AC Overhang from deviating from the center value, thereby helping to avoid internal short circuits and ensure safe use.

[0069] The electrical device provided by the present invention adopts the winding core, which is beneficial to avoiding internal short circuits and ensuring safe use.

[0070] The manufacturing method of the winding core provided by the present invention can prepare the above-mentioned winding core, which is beneficial to avoiding internal short circuits and ensuring safe use. BRIEF DESCRIPTION OF THE DRAWINGS

[0071] Figure 1Schematic diagram of the structure of the winding core provided by the present invention;

[0072] Figure 2 This is a first structural schematic diagram of the first positive electrode sheet provided by the present invention;

[0073] Figure 3 This is a schematic structural diagram of the second positive electrode sheet provided by the present invention;

[0074] Figure 4 This is a schematic structural diagram of the third positive electrode sheet provided by the present invention;

[0075] Figure 5 Schematic diagram of the structure of the fourth positive electrode sheet provided by the present invention;

[0076] Figure 6 Schematic diagram of the structure of the fifth positive electrode sheet provided by the present invention;

[0077] Figure 7 This is a schematic diagram of the first part of the structure of the first positive electrode sheet provided by the present invention;

[0078] Figure 8 This is a schematic diagram of the second part of the structure of the first positive electrode sheet provided by the present invention;

[0079] Figure 9 1 is a schematic structural diagram of the sixth positive electrode sheet provided by the present invention;

[0080] Figure 10 This is a schematic structural diagram of the sixth positive electrode sheet provided by the present invention at the winding head end;

[0081] Figure 11 This is a schematic structural diagram of the sixth positive electrode sheet provided by the present invention at the winding end;

[0082] Figure 12 1 is a schematic structural diagram of the seventh positive electrode sheet provided by the present invention;

[0083] Figure 13 This is a partial structural diagram of the seventh positive electrode sheet provided by the present invention;

[0084] Figure 14 This is a second structural schematic diagram of the first positive electrode sheet provided by the present invention;

[0085] Figure 15 This is a schematic diagram of the first structure of the positive electrode sheet and the negative electrode sheet provided by the present invention when they are not wound;

[0086] Figure 16 This is a second structural schematic diagram of the present invention when the positive electrode sheet and the negative electrode sheet are not wound;

[0087] Figure 17This is a schematic structural diagram of the electrode coil provided by the present invention when it is not cut;

[0088] Figure 18 This is a schematic structural diagram of the insulating layer attached to the electrode coil provided by the present invention;

[0089] Figure 19 It is a structural schematic diagram of the winding device provided by the present invention;

[0090] In the picture:

[0091] 100, positive electrode; 10, electrode body; 11, current collector; 111, tab; 112, marking portion; 12, active material layer; 13, insulating coating; 20, insulating member; 20a, first edge; 20b, second edge; 20c, third edge; 20d, fourth edge; 21, first insulating portion; 22, second insulating portion; 23, third insulating portion; 24, fourth insulating portion; 200, negative electrode; 20 1. Fifth edge; 202. Sixth edge; 203. Seventh edge; 204. Eighth edge; 210. Negative electrode tab; 300. Separator; 400. Electrode sheet coil; 510. Positive electrode sheet coil unwinding mechanism; 520. Positioning mechanism; 530. Gluing mechanism; 540. Cutter mechanism; 550. First separator unwinding mechanism; 560. Winding needle; 570. Second separator unwinding mechanism; 580. Negative electrode sheet unwinding mechanism. DETAILED DESCRIPTION

[0092] The present invention will be further described in detail below with reference to the accompanying drawings and examples. It will be understood that the specific embodiments described herein are intended only to illustrate the present invention and are not intended to limit the present invention. It should also be noted that, for ease of description, the accompanying drawings only illustrate portions relevant to the present invention, not all structures.

[0093] In the description of the present invention, unless otherwise expressly specified or limited, the terms "connected," "connected," and "fixed" should be understood in a broad sense. For example, they may refer to fixed connections, detachable connections, or integration; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; and internal communication between two components or interaction between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention in specific circumstances.

[0094] In the present invention, unless otherwise expressly specified or limited, a first feature being "above" or "below" a second feature may include the first and second features being in direct contact, or may include the first and second features being in contact not directly but through another feature between them. Furthermore, a first feature being "above," "above," and "above" a second feature may include the first feature being directly above or obliquely above the second feature, or may simply mean that the first feature is higher in level than the second feature. A first feature being "below," "below," and "below" a second feature may include the first feature being directly below or obliquely below the second feature, or may simply mean that the first feature is lower in level than the second feature.

[0095] In the description of this embodiment, the terms "upper," "lower," "right," and other orientations or positional relationships are based on the orientations or positional relationships shown in the accompanying drawings and are intended solely for ease of description and simplified operation. They do not indicate or imply that the devices or components referred to must have, be constructed, or operate in a specific orientation. Therefore, they should not be construed as limitations on the present invention. Furthermore, the terms "first" and "second" are used solely for descriptive purposes and have no special meanings.

[0096] Example 1

[0097] This embodiment provides an electrical device, including a battery cell, wherein the battery cell includes a winding core and an electrolyte. Figure 1 As shown, the winding core includes a stacked positive electrode sheet 100, a separator 300, and a negative electrode sheet 200. The separator 300 is located between the positive and negative electrode sheets 100 and 200 to prevent contact and short circuits. The positive electrode sheet 100, separator 300, and negative electrode sheet 200 are stacked and wound to form the winding core. Battery cells operate by the movement of metal ions between the positive and negative electrode sheets 100 and 200, providing power to electrical devices.

[0098] In some embodiments, the electrical device may be a vehicle, a mobile phone, a laptop computer, an electric tool, an electric toy, etc.

[0099] During the winding process for preparing the core, the winding heads of the positive electrode sheet 100, separator 300, and negative electrode sheet 200 cooperate with the winding needle. The needle rotates to sequentially wind and extrude the positive electrode sheet 100, separator 300, and negative electrode sheet 200. The winding head refers to the starting end of the winding process during the preparation of the core, i.e., the end located at the center of the core. The winding tail refers to the ending end of the winding process during the preparation of the core, i.e., the end located outside the core.

[0100] In some embodiments, the positive electrode sheet 100 and the negative electrode sheet 200 have different dimensions in the axial direction of the winding core. Specifically, the positive electrode sheet 100 is smaller than the negative electrode sheet 200 in the axial direction of the winding core. This dimension difference is called AC Overhang (OH). The purpose of this design is to ensure that the negative electrode sheet 200 exceeds the positive electrode sheet 100 in the axial direction of the winding core, avoiding safety hazards and performance degradation caused by exposed electrode sheet edges.

[0101] Since the cut winding tail ends and winding beginning ends of the positive electrode sheet 100 and the negative electrode sheet 200 have no traction tension during winding, the positions of the positive electrode sheet 100 and the negative electrode sheet 200 at the winding beginning and end are offset, that is, the problem of poor winding tail swing occurs, which reduces the AC overhang and easily causes the burrs of the positive electrode sheet 100 to contact the negative electrode sheet 200, causing internal short circuit problems, which can easily cause battery cell safety risks.

[0102] To solve the above problems, Figure 2 As shown, in some embodiments, the positive electrode sheet 100 includes a sheet body 10 and an insulating member 20. The sheet body 10 includes a current collector 11 and an active material layer 12 coated on at least one surface of the current collector 11. The active material layer 12 is specifically a positive electrode active material layer. The opposite ends of the sheet body 10 along a first direction X are respectively a winding start end and a winding end. The insulating member 20 covers a portion of the active material layer 12 along a second direction Y at the winding start end and the winding end. The first direction X and the second direction Y are perpendicular to each other. The first direction X is the length direction of the sheet body 10, and the second direction Y is the width direction of the sheet body 10, which is also the axial direction of the winding core.

[0103] In the positive electrode sheet 100, by providing the insulating member 20, the size of the active material layer 12 exposed at the winding head end and the winding tail end of the positive electrode sheet 100 along the second direction Y can be reduced, and then the AC Overhang at the winding head end and the winding tail end can be increased on the basis of the overall size of the positive electrode sheet and the negative electrode sheet remaining unchanged, thereby avoiding the A-COverhang deviating from the center value after the winding is completed, and avoiding the burrs on the positive electrode sheet 100 from contacting the negative electrode active material layer on the negative electrode sheet 200, thereby reducing the probability of internal short circuit of the battery cell and the safety risk of the battery cell.

[0104] In some embodiments, such as Figure 2As shown, one end of the insulating member 20 along the first direction X coincides with the edge of the pole piece body 10 along the first direction X. In other words, the insulating member 20 is aligned with the edge of the pole piece body 10 in the width direction, and the insulating member 20 extends along the first direction X from the edge of the pole piece body 10 along the first direction X. This arrangement ensures that the insulating member 20 does not extend beyond the pole piece body 10 along the first direction X, making it easier to cut the insulating member 20 and the pole piece body 10 together, simplifying the processing process, and improving the positioning accuracy of the insulating member 20 and the pole piece body 10.

[0105] In some other embodiments, such as Figure 3 As shown, one end of the insulating member 20 along the first direction X exceeds the edge of the pole piece body 10 along the first direction X. This arrangement can ensure that the insulating member 20 covers the edge of the pole piece body 10 along the first direction X, and can improve the tolerance for the position accuracy of the insulating member 20 and the pole piece body 10.

[0106] In some other embodiments, such as Figure 4 As shown, at the winding head end and the winding tail end, the edge of the insulating member 20 along the first direction X on one coincides with the edge of the pole piece body 10 along the first direction X, and one end of the insulating member 20 along the first direction X on the other exceeds the edge of the pole piece body 10 along the first direction X.

[0107] In some other embodiments, the pole piece body 10 may be provided with an insulating member 20 only at the winding head end or only at the winding tail end, which can increase the AC overhang at the winding head end or the winding tail end and solve the problem of poor winding tail at the winding head end or the winding tail end.

[0108] In some embodiments, such as Figure 2-Figure 4 As shown, the current collector 11 is a long, rectangular sheet. Correspondingly, the coverage area of ​​the active material layer 12 is rectangular. The electrode body 10 has coverage areas at each of the four corners of the active material layer 12, each of which is provided with an insulating member 20. This arrangement increases the dimensional difference between the positive electrode sheet 100 and the negative electrode sheet 200 in the second direction Y, thereby increasing the AC overhang, and improves the tail swing problem at both the beginning and end of the winding.

[0109] It should be noted here that the corner region refers to a region enclosed by two adjacent right-angled sides of the active material layer 12 .

[0110] Specifically, the four covering areas are the first covering area, the second covering area, the third covering area, and the fourth covering area. The first covering area and the second covering area are located at the winding head end of the pole piece body 10, and are respectively located at the two ends of the winding head end along the second direction Y; the third covering area and the fourth covering area are located at the winding tail end of the pole piece body 10, and are respectively located at the two ends of the winding tail end along the second direction Y. Among them, the first covering area and the third covering area are located at the two ends of the pole piece body 10 along the first direction and are arranged opposite to each other; the second covering area and the fourth covering area are located at the two ends of the pole piece body 10 along the first direction and are arranged opposite to each other.

[0111] In some other embodiments, only one corner of the winding head and the winding tail of the electrode body 10 is provided with a covering region, and the covering region is provided with an insulating member 20. In other words, an insulating member 20 is provided at each of the winding head and the winding tail, and the exposed size of the active material layer 12 is reduced from one side in the second direction Y.

[0112] In some embodiments, such as Figure 5 As shown, the two covering areas are a first covering area located at the beginning of the winding and a second covering area located at the end of the winding. The first covering area and the second covering area are located on the same side of the pole piece body 10 along the second direction Y. The first covering area and the second covering area are both provided with insulating members 20. In other words, the two insulating members 20 on the pole piece body 10 are arranged opposite each other along the first direction X.

[0113] Optionally, the first covering area and the second covering area are located on a side of the current collector 11 where the tab 111 is provided; or, the first covering area and the second covering area are located on a side of the current collector 11 opposite to the tab 111 .

[0114] In some embodiments, such as Figure 6 As shown, the two covering areas are a first covering area at the beginning of the winding and a second covering area at the end of the winding. The first covering area and the second covering area are respectively located on both sides of the pole piece body 10 along the second direction Y. The first covering area and the second covering area are both provided with insulating members 20. In other words, the two insulating members 20 on the pole piece body 10 are arranged diagonally.

[0115] In some embodiments, the electrode body 10 further includes a tab 111 and an insulating coating 13. The current collector 11 includes a first end and a second end disposed opposite each other along the second direction Y, with the tab 111 connected to the first end. At least a portion of the insulating coating 13 is located between the tab 111 and the active material layer 12, serving as an insulating barrier to prevent short circuits and thereby improve the safety, stability, and cycle life of the battery cell.

[0116] It should be noted here that during the processing of the electrode body 10, the insulating coating 13 and the active material layer 12 are coated on the current collector 11. Due to the limitations of the coating accuracy and the fluidity of the coating material, in the actual processing process, there is a situation where the edge of the insulating coating 13 close to the active material layer 12 coincides with the edge of the active material layer 12, and there is also a situation where one side edge of the insulating coating 13 covers the active material layer 12; correspondingly, there is a situation where the edge of one side of the insulating coating 13 close to the pole ear 111 coincides with the edge of the current collector 11, and there is also a situation where the side edge extends to the pole ear 111, but the above situations can ensure that at least part of the insulating coating 13 is located between the active material layer 12 and the pole ear 111.

[0117] Optionally, the insulating coating 13 may be a TF8 ceramic coating, which has a good insulating effect.

[0118] Optionally, a plurality of tabs 111 are provided, and the plurality of tabs 111 are arranged at intervals along the first direction X.

[0119] In some embodiments, such as Figure 7 As shown, the insulating member 20 covering the first end includes a first insulating portion 21 and a second insulating portion 22. The first insulating portion 21 covers at least a portion of the insulating coating 13, and the second insulating portion 22 covers a portion of the active material layer 12. This arrangement allows the insulating member 20 disposed at the first end to extend beyond the edge a of the active material layer 12 along the second direction Y, thereby completely covering the edge a of the active material layer 12 along the second direction Y. This prevents the CCD camera from capturing the edge a of the active material layer 12 along the second direction Y during edge detection, thereby preventing the A-Coverhang from being misjudged as deviating from the center value, thereby improving detection accuracy.

[0120] In some embodiments, such as Figure 8 As shown, the insulating member 20 has a rectangular coverage area. The insulating member 20 at the first end includes a first edge 20a, a second edge 20b, a third edge 20c, and a fourth edge 20d, which are connected in sequence. The first edge 20a is parallel to the edge of the pole piece body 10 along the first direction X, and the second edge 20b is parallel to the edge of the pole piece body 10 along the second direction Y. The distance between the third edge 20c and the first edge 20a along the second direction Y remains constant, making it easier to attach the insulating member 20 to the edge of the pole piece body 10 and improving the positioning accuracy of the insulating member 20.

[0121] In some embodiments, the insulating member 20 is a rectangular film layer, and a dimension L of the insulating member 20 along the first direction X is 100-500 mm, which is conducive to reducing AC overhang at the winding tail end and the winding head end.

[0122] By way of example, typical but non-limiting values ​​of L are 100 mm, 150 mm, 200 mm, 250 mm, 300 mm, 350 mm, 400 mm, 450 mm, 500 mm.

[0123] In some embodiments, a dimension W1 of the first insulating portion 21 along the second direction Y is 0.5-5 mm, so as to fully cover the edge a of the active material layer 12 and avoid the possibility of false positives during edge detection.

[0124] Exemplarily, typical non-limiting values ​​of W1 are 0.5 mm, 1 mm, 1.5 mm, 2 mm, 2.5 mm, 3 mm, 3.5 mm, 4 mm, 4.5 mm, and 5 mm.

[0125] In some embodiments, the dimension W2 of the second insulating portion 22 along the second direction Y is 0.5-20 mm, so as to increase the size of the active material layer 12 covered along the second direction Y, increase AC overhang, and avoid problems caused by tail swinging during the winding process.

[0126] In some other embodiments, such as Figure 9 and Figure 10 As shown, the distance between the third edge 20c and the first edge 20a changes gradually.

[0127] For example, the distance between the third edge 20c and the first edge 20a gradually increases from the middle of the electrode body 10 toward the end along the first direction X. This arrangement maximizes the exposed dimension of the active material layer 12 along the second direction Y at the end of the electrode body 10, thereby maximizing the AC overhang at the leading and trailing ends during winding, which helps to solve the problem of poor tail swing.

[0128] For example, Figure 10 As shown, the insulating member 20 at the winding head end is a trapezoidal film layer. In the insulating member 20 at the winding head end, the size of the second insulating portion 22 gradually decreases along the second direction Y from the winding head end to the winding tail end. Specifically, the size of the second insulating portion 22 along the second direction Y on the side close to the winding head end is W2, and the size of the second insulating portion 22 along the second direction Y on the side away from the winding head end is W3, where W2>W3.

[0129] For example, Figure 11 As shown, the insulating member 20 at the winding end is a trapezoidal film layer. In the insulating member 20 at the winding end, the size of the second insulating portion 22 gradually increases along the second direction Y from the winding beginning to the winding end. Specifically, the size of the second insulating portion 22 along the second direction Y on the side close to the winding beginning is W3, and the size of the second insulating portion 22 along the second direction Y on the side away from the winding beginning is W2, where W2>W3.

[0130] In some embodiments, such as Figure 9 and Figure 10 As shown, the insulating member 20 is a trapezoidal film layer, and the dimension L of the insulating member 20 along the first direction X is 100-500 mm, which is conducive to reducing the A-Coverhang at the winding tail end and the winding head end.

[0131] By way of example, typical but non-limiting values ​​of L are 100 mm, 150 mm, 200 mm, 250 mm, 300 mm, 350 mm, 400 mm, 450 mm, 500 mm.

[0132] In some embodiments, a dimension W1 of the first insulating portion 21 along the second direction Y is 0.5-5 mm, so as to fully cover the edge a of the active material layer 12 and avoid the possibility of false positives during edge detection.

[0133] Exemplarily, typical non-limiting values ​​of W1 are 0.5 mm, 1 mm, 1.5 mm, 2 mm, 2.5 mm, 3 mm, 3.5 mm, 4 mm, 4.5 mm, and 5 mm.

[0134] In some embodiments, the maximum dimension W2 of the second insulating portion 22 along the second direction Y is less than or equal to 20 mm, and the minimum dimension W3 of the second insulating portion 22 along the second direction Y is greater than or equal to 0.5 mm, so as to maximize the size of the active material layer 12 covered along the second direction Y, increase the AC overhang, and avoid poor tail swinging during the winding process.

[0135] In some embodiments, such as Figure 7 As shown, the insulating member 20 covering the second end includes a third insulating portion 23 and a fourth insulating portion 24. The third insulating portion 23 partially covers the active material layer 12, and the fourth insulating portion 24 extends beyond the current collector 11 along the second direction Y. This arrangement allows the insulating member 20 disposed at the second end to extend beyond the edge b of the active material layer 12 along the second direction Y, thereby completely covering the edge b of the active material layer 12 along the second direction Y. This prevents the CCD camera from capturing the edge b of the active material layer 12 along the second direction Y during edge detection, thereby preventing the AC overhang from being misjudged as deviating from the center value, thereby improving detection accuracy.

[0136] In some embodiments, a dimension W4 of the fourth insulating portion 24 along the second direction Y is 0-2 mm, preferably 1-2 mm, so as to fully cover the edge b of the active material layer 12 .

[0137] By way of example, typical non-limiting values ​​of W4 are 0.2 mm, 0.4 mm, 0.6 mm, 0.8 mm, 1 mm, 1.2 mm, 1.4 mm, 1.6 mm, 1.8 mm, and 2 mm.

[0138] In some other embodiments, such as Figure 12 As shown, the insulating member 20 only covers the active material layer 12 , and one side edge of the insulating member 20 along the second direction Y overlaps with one side edge of the active material layer 12 along the second direction Y.

[0139] For example, Figure 13 As shown, the insulating member 20 at the first end only covers a portion of the active material layer 12. A corner region of the insulating member 20 overlaps with a corner region of the active material layer 12; that is, a side edge of the insulating member 20 along the second direction Y overlaps with an edge a of the active material layer 12, and a side edge of the insulating member 20 along the first direction X overlaps with a side edge of the active material layer 12 along the first direction X.

[0140] For example, Figure 13 As shown, the insulating member 20 at the second end only covers a portion of the active material layer 12. A corner region of the insulating member 20 overlaps with a corner region of the active material layer 12; that is, a side edge of the insulating member 20 along the second direction Y overlaps with an edge b of the active material layer 12, and a side edge of the insulating member 20 along the first direction X overlaps with a side edge of the active material layer 12 along the first direction X.

[0141] In some other embodiments, one of the two insulating members 20 located at both ends of the first end along the first direction X may only cover the active material layer 12 , and the other insulating member 20 may cover part of the active material layer 12 and part of the insulating coating 13 .

[0142] In some other embodiments, one of the two insulating members 20 located at both ends of the second end along the first direction X may only cover the active material layer 12 , and the other insulating member 20 may extend out of the active material layer 12 along the second direction Y.

[0143] In some other embodiments, the insulating member 20 located at the first end covers part of the insulating coating 13 and part of the active material layer 12, while the insulating member 20 located at the second end only covers the active material layer 12; or, the insulating member 20 located at the first end only covers the active material layer 12, and the insulating member 20 located at the second end extends beyond the edge of the pole piece body 10 along the second direction Y.

[0144] It should be noted here that the specific configurations of the insulating members 20 at the first end and the second end can be combined arbitrarily and are not limited to the listed compositions.

[0145] In some embodiments, the insulating member 20 is a tape having an adhesive layer on one side thereof, which can adhere the insulating member 20 to the pole piece body 10 to improve the fixing effect, simplify the process, and reduce the cost.

[0146] In some embodiments, in order to facilitate edge detection, the CCD camera captures the third edge 20c of the insulating part 20 as the edge of the active material layer 12 along the second direction Y to avoid misjudgment. The insulating part 20 and the active material layer 12 have different colors to make it easier for the CCD to perform edge detection.

[0147] like Figure 14 As shown, active material layers 12 are provided on both sides of the current collector 11 in the thickness direction, and insulating members 20 are provided correspondingly on the active material layers 12 on both sides.

[0148] In order to facilitate the attachment of the insulating member 20 to the pole piece body 10, in some embodiments, such as Figure 13 As shown, a marking portion 112 is provided on the pole piece body 10 so that the attachment position of the insulating member 20 can be obtained by identifying the marking portion 112 .

[0149] In some embodiments, the marking portion 112 is a marking hole or a marking notch to simplify the structure and facilitate identification.

[0150] In some embodiments, the marking portion 112 can be made of a material having a different color than the electrode body 10 in which it is located, to facilitate identification of the marking portion 112. For example, when the marking portion 112 is disposed on the active material layer 12, the color of the marking portion 112 is different from that of the active material layer 12; when the marking portion 112 is disposed on the current collector 11, the color of the marking portion 112 is different from that of the current collector 11; and when the marking portion 112 is disposed on the insulating coating 13, the color of the marking portion 112 is different from that of the insulating coating 13.

[0151] In some embodiments, the marking portion 112 is provided on the first tab 111 in the direction from the winding head end to the winding tail end. The marking portion 112 is close to the attachment position of the insulating member 20, which facilitates improving the acquisition accuracy of the attachment position of the insulating member 20.

[0152] When the positive electrode sheet 100 is stacked on the negative electrode sheet 200, Figure 15 As shown, the negative electrode tab 210 of the negative electrode sheet 200 and the tab 111 of the positive electrode sheet 100 are located on the same side, at least one side edge of the negative electrode sheet 200 along the first direction X exceeds the positive electrode sheet 100, and at least one side edge of the negative electrode sheet 200 along the second direction Y exceeds the positive electrode sheet 100.

[0153] In some embodiments, the negative electrode sheet 200 includes a fifth edge 201 and a sixth edge 202 that are oppositely disposed along the second direction Y. The insulating member 20 includes a first edge 20a and a third edge 20c that are oppositely disposed along the second direction Y. The third edge 20c is located on the active material layer 12, i.e., the third edge 20c is located on a side of the first edge 20a that is closer to the center of the active material layer 12 along the second direction Y. The projection of the fifth edge 201 along the stacking direction of the positive electrode sheet 100 and the negative electrode sheet 200 is located on a side of the adjacent first edge 20a that is farther away from the third edge 20c. In other words, the fifth edge 201 extends outside the third edge 20c of the insulating member 20 on the corresponding side along the second direction Y, thereby increasing AC overhang and reducing the impact of tail swing on the winding core.

[0154] In some other embodiments, the projection of the fifth edge 201 along the stacking direction of the positive electrode sheet 100 and the negative electrode sheet 200 coincides with the projection of the first edge 20 a .

[0155] In some other embodiments, the projection of the fifth edge 201 along the stacking direction is located between the first edge 20a and the third edge 20c.

[0156] In some embodiments, such as Figure 15 As shown, the sixth edge 202 is located outside the corresponding first edge 20 a of the insulating member 20 along the second direction Y, so as to increase the size difference between the positive electrode sheet 100 and the negative electrode sheet 200 in the second direction Y.

[0157] In some embodiments, the negative electrode plate 200 further includes a seventh edge 203 and an eighth edge 204 disposed opposite to each other along the first direction X, and the third edge 20c and the eighth edge 204 extend outward from the positive electrode plate 100 along the first direction X.

[0158] In some embodiments, such as Figure 16 As shown, at the winding tail end and the winding head end of the positive electrode sheet 100, the exposed size of the active material layer 12 along the second direction Y is the distance between the third edges 20c of the two insulating members 20 opposite to each other along the second direction Y, so that the distance between the fifth edge 201 of the negative electrode sheet 200 and the third edge 20c of the insulating member 20 at the first end along the second direction Y is the corresponding AC overhang, hereinafter referred to as OH1; correspondingly, the distance between the sixth edge 202 of the negative electrode sheet 200 and the third edge 20c of the insulating member 20 at the second end along the second direction Y is the corresponding AC overhang, hereinafter referred to as OH2.

[0159] It can be understood that if the insulating member 20 is not provided, the distance between the fifth edge 201 and the edge of the active material layer 12 at the first end along the second direction Y is AC overhang, recorded as OH3. It can be seen that by providing the insulating member 20 at the first end, the AC overhang can be increased from the original OH3 to OH1, which is beneficial to reducing the impact of poor tail swing on the performance of the core.

[0160] Correspondingly, if the insulating member 20 is not provided, the distance between the sixth edge 202 and the edge of the active material layer 12 at the second end along the second direction Y is AC overhang, recorded as OH4. It can be seen that by providing the insulating member 20 at the second end, the A-Coverhang can be increased from the original OH4 to OH2, which is beneficial to reducing the impact of poor tail swing on the performance of the core.

[0161] Since the first end is provided with an insulating coating 13, the thickness of the first end and the second end are different, and the tension is different during the winding process. As the number of winding layers increases, the slight difference in thickness is accumulated and amplified, which may easily lead to AB surface misalignment at the end of winding.

[0162] To solve the above problem, in some embodiments, OH1 is greater than or equal to OH2, which is helpful to eliminate the problem of AB plane misalignment.

[0163] In some embodiments, the difference between OH1 and OH2 may be greater than or equal to 0 and less than or equal to 2 mm, that is, 0≤OH1-OH2≤2 mm.

[0164] For example, typical non-limiting values ​​of the difference between OH1 and OH2 may be 0 mm, 0.2 mm, 0.4 mm, 0.6 mm, 0.8 mm, 1 mm, 1.2 mm, 1.4 mm, 1.6 mm, 1.8 mm, 2 mm.

[0165] In some embodiments, OH1 may be greater than or equal to 1.5 mm and less than or equal to 21 mm. Within this range, A-Coverhang can be increased while ensuring that the active material layer 12 has a certain exposed size along the second direction Y, which is beneficial to improving the core performance.

[0166] Exemplarily, typical non-limiting values ​​of OH1 may be 1.5 mm, 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, 10 mm, 11 mm, 12 mm, 13 mm, 14 mm, 15 mm, 16 mm, 17 mm, 18 mm, 19 mm, 20 mm, 21 mm.

[0167] In some embodiments, OH2 can be greater than or equal to 1.3 mm and less than or equal to 21 mm. Within this range, A-Coverhang can be increased while ensuring that the active material layer 12 has a certain exposed size along the second direction Y, which is beneficial to improving the core performance.

[0168] Exemplarily, typical non-limiting values ​​of OH2 may be 1.3 mm, 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, 10 mm, 11 mm, 12 mm, 13 mm, 14 mm, 15 mm, 16 mm, 17 mm, 18 mm, 19 mm, 20 mm, 21 mm.

[0169] Example 2

[0170] This embodiment provides a method for manufacturing a winding core, which is used to manufacture the winding core in the first embodiment. The method for manufacturing the winding core includes:

[0171] Prepare a positive electrode sheet 100, so that the active material layer 12 at the winding head end and / or the winding tail end of the positive electrode sheet 100 is covered with an insulating member 20;

[0172] The negative electrode sheet 200 , the separator 300 and the positive electrode sheet 100 are stacked in sequence and wound along the second direction Y as the axis to form a winding core.

[0173] In this winding core preparation method, an insulating member 20 is used to cover part of the active material layer 12 at the winding head end and / or winding tail end of the positive electrode sheet 100 to increase the size difference between the positive electrode sheet 100 and the negative electrode sheet 200 at the winding head end and / or winding tail end, that is, to increase the AC overhang, thereby reducing the probability of tail swinging and improving the winding core quality.

[0174] In some embodiments, such as Figure 17 As shown, the electrode body 10 is obtained by cutting the electrode roll 400, wherein the electrode roll 400 includes a substrate and an active layer coated on the substrate. After cutting the electrode roll 400, the substrate is cut into a current collector 11 of a certain length, and the active layer is then cut into an active material layer 12 coated on the current collector 11.

[0175] In some embodiments, one end of the insulating member 20 along the first direction X coincides with an edge of the electrode body 10 along the first direction X. In this case, when preparing the positive electrode sheet 100, the insulating member 20 can be attached first, and then the insulating member 20 and the electrode body 10 can be cut simultaneously to prepare the positive electrode sheet 100. This method can simplify the process, reduce costs, and improve production efficiency.

[0176] Exemplarily, preparing the positive electrode sheet 100 specifically includes:

[0177] Unwinding the pole piece coil 400 to achieve continuous cutting;

[0178] Identify the marking portion 112 on the electrode sheet coil 400 to obtain the attachment position d and the cutting line c on the electrode sheet coil 400. The cutting line c extends along the second direction Y, and a portion of the cutting line c is located within the attachment position d;

[0179] like Figure 18 As shown, the insulating layer is attached to the attachment position d;

[0180] The electrode sheet coil 400 and the insulating layer are cut along the cutting line c to obtain the positive electrode sheet 100 .

[0181] By identifying the marking portion 112 , the cutting line c and the attachment position d can be obtained, thereby improving the position accuracy of the insulating member 20 and facilitating ensuring the dimensional accuracy of the electrode body 10 after cutting.

[0182] It can be understood that the multiple pole piece bodies 10 in the pole piece coil 400 are connected end to end in sequence, the winding tail end of the previous pole piece body 10 is connected to the winding head end of the next pole piece body 10, and the connection position between the two is the cutting line c.

[0183] In some embodiments, the attachment position d is symmetrically arranged relative to the cutting line c, so that the dimensions of the insulating members 20 on two adjacent electrode bodies 10 along the first direction X are equal after cutting.

[0184] In some other embodiments, the lengths of the attachment positions d on both sides of the cutting line c along the first direction X may be different.

[0185] In some other embodiments, the cutting line c can coincide with a side edge of the attachment position d along the first direction X, so that after cutting, of the two adjacent pole piece bodies 10, the winding head end (or winding tail end) of one pole piece body 10 has an insulating part 20, and the winding tail end (or winding head end) of the other pole piece body 10 is not provided with an insulating part 20.

[0186] In some embodiments, the attachment positions d of the pole piece roll 400 at the first end and the second end can be located on both sides of the cutting line c, respectively, so that after cutting, the winding head end of one pole piece body 10 is provided with an insulating part 20 at the first end (or the second end), and the winding head end of the other pole piece body 10 is provided with an insulating part 20 at the second end (or the first end).

[0187] To accurately determine the cutoff line c, the marking portion 112 is located on the first tab 111 pointing from the winding head end to the winding tail end. By identifying the marking portion 112 and the distance D1 between the marking portion 112 and the edge of the winding head end of the pole piece body 10 along the first direction X, the cutoff line c can be determined, thereby performing the attachment and cutting processes.

[0188] In some embodiments, the winding device for preparing the positive electrode sheet 100 can be as follows: Figure 19 As shown, the winding equipment includes a positive electrode sheet unwinding mechanism 510, a first diaphragm unwinding mechanism 550, a second diaphragm unwinding mechanism 570, a negative electrode sheet unwinding mechanism 580 and a winding needle 560. The electrode sheet coil 400, the first diaphragm, the second diaphragm and the negative electrode sheet 200 are all unwound by the corresponding unwinding mechanisms and conveyed toward the winding needle 560; wherein, a positioning mechanism 520, a gluing mechanism 530 and a cutting mechanism 540 are sequentially arranged between the positive electrode sheet unwinding mechanism 510 and the winding needle 560, the positioning mechanism 520 is used to identify the marking portion 112, the gluing mechanism 530 is used to attach an insulating layer to the electrode sheet coil 400, and the cutting mechanism 540 is used to cut the electrode sheet coil 400, thereby preparing the positive electrode sheet 100.

[0189] Optionally, the winding device also includes a controller, which is respectively connected to the positioning mechanism 520, the gluing mechanism 530 and the cutting mechanism 540. After the positioning mechanism 520 identifies the marking part 112, it sends a signal to the controller. The controller determines the attachment position d and the cutting line c according to the received model, and controls the gluing mechanism 530 to attach according to the attachment position d, and then controls the cutting mechanism 540 to cut according to the cutting line c, thereby preparing the positive electrode sheet 100.

[0190] The positive electrode sheet 100 and the first separator are transported to the position of the winding needle 560 , and are stacked with the second separator and the negative electrode sheet 200 under the action of the winding needle 560 and wound into a winding core.

[0191] In some embodiments, the positioning mechanism 520 obtains the position of the marking portion 112 by acquiring an image, thereby realizing the position of the gluing position d and the cutting line c.

[0192] It should be noted here that the cutter mechanism 540 and the gluing mechanism 530 can adopt any structure in the prior art that can achieve cutting and gluing, and will not be described in detail here.

[0193] In some other embodiments, the insulating member 20 extends beyond the edge of the pole piece body 10 along the first direction X, that is, the insulating member 20 extends out of the pole piece body 10 along the first direction X. At this time, it is necessary to first cut the pole piece coil to prepare a certain length of the pole piece body 10, and then attach the insulating member 20 to the pole piece body 10.

[0194] Exemplarily, preparing the positive electrode sheet 100 includes:

[0195] Unwinding pole piece coil 400;

[0196] Identify the marking portion 112 on the electrode sheet coil 400 to obtain the position of the cutting line c of the electrode sheet coil 400;

[0197] Cutting the electrode coil 400 along the cutting line c to obtain the electrode body 10;

[0198] An insulating member 20 is attached to the winding beginning and / or the winding end of the pole piece body 10 .

[0199] In some embodiments, the method for manufacturing the winding core further includes identifying the edges of the tab side and the non-tab side of the winding core to detect whether the size difference between the positive electrode sheet 100 and the negative electrode sheet 200 is within a preset range.

[0200] Specifically, a CCD camera is positioned near the winding needle 560 and electrically connected to the controller. The CCD camera captures image information from both the tab and non-tab sides of the winding core to identify the edges of these two sides. The CCD camera transmits the captured image information to the controller, which then determines the dimensional difference between the positive and negative electrode sheets 100 and 200 based on the image information. The controller compares this difference with a preset range to determine whether the dimensional difference exceeds the preset range. If so, the winding core is deemed to have an overhang problem; otherwise, the winding core is considered to be of normal quality.

[0201] It should be noted here that the CCD camera is an existing structure in this field, and the structure and working principle of the CCD camera will not be described in detail here.

[0202] Obviously, the above embodiments of the present invention are merely examples for the purpose of clearly illustrating the present invention and are not intended to limit the embodiments of the present invention. A person skilled in the art would be able to make various obvious changes, readjustments, and substitutions without departing from the scope of protection of the present invention. It is not necessary and impossible to enumerate all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the claims of the present invention.

Claims

1. A pole piece, characterized in that: include: A pole piece body (10), the pole piece body (10) comprising a current collector (11) and an active material layer (12) coated on at least one surface of the current collector (11), the pole piece body (10) comprising a winding head end and a winding tail end arranged opposite to each other along a first direction; An insulating member (20) covers a portion of the active material layer (12) along the second direction at the winding head end and / or the winding tail end, wherein at least one end of the insulating member (20) along the first direction coincides with an edge of the pole piece body (10) along the first direction at the winding head end and / or the winding tail end, or at least one insulating member (20) extends beyond the edge of the pole piece body (10) along the first direction along the first direction, and the first direction is perpendicular to the second direction.

2. The pole piece according to claim 1, characterized in that: The pole piece body (10) comprises: a first covering area and a second covering area located at the winding head end, wherein the first covering area and the second covering area are arranged at two ends of the winding head end along the second direction; a third covering area and a fourth covering area located at the winding tail end, wherein the third covering area and the fourth covering area are located at two ends of the winding tail end along the second direction; The first covering area and the third covering area are located at two ends of the pole piece body (10) along the first direction, the second covering area and the fourth covering area are located at two ends of the pole piece body (10) along the first direction, and the first covering area, the second covering area, the third covering area and the fourth covering area are all provided with the insulating member (20).

3. The pole piece according to claim 1, characterized in that: The pole piece body (10) comprises a first covering area located at the winding head end and a second covering area located at the winding tail end, the first covering area and the second covering area are located on the same side of the pole piece body (10) along the second direction, and the first covering area and the second covering area are both provided with insulating parts.

4. The pole piece according to claim 1, characterized in that: The pole piece body (10) comprises a first covering area located at the winding head end and a second covering area located at the winding tail end, the first covering area and the second covering area are respectively located on both sides of the pole piece body (10) along the second direction, and the first covering area and the second covering area are both provided with insulating parts.

5. The pole piece according to any one of claims 1 to 4, characterized in that: The pole piece body (10) further comprises a pole ear (111) and an insulating coating (13); the current collector (11) comprises a first end and a second end arranged opposite to each other along a second direction; the first end is connected to the pole ear (111); and at least a portion of the insulating coating (13) is located between the pole ear (111) and the active material layer (12); The insulating member (20) covering the first end includes a first insulating portion (21) and a second insulating portion (22), wherein the first insulating portion (21) covers at least a portion of the insulating coating (13), and the second insulating portion (22) covers a portion of the active material layer (12); Alternatively, the insulating member (20) covering the first end only covers the active material layer (12).

6. The pole piece according to claim 5, characterized in that: The insulating member (20) comprises a first edge (20a), a second edge (20b), a third edge (20c), and a fourth edge (20d) connected in sequence, wherein the first edge (20a) is parallel to the edge of the pole piece body (10) along the first direction, and the second edge (20b) is parallel to the edge of the pole piece body (10) along the second direction; Along the second direction, the distance between the third edge (20c) and the first edge (20a) remains unchanged, or the distance between the third edge (20c) and the first edge (20a) changes gradually.

7. The pole piece according to claim 6, characterized in that: The insulating member (20) is a rectangular film layer, and the size of the insulating member (20) along the first direction is 100-500 mm; And / or, the dimension of the first insulating portion (21) along the second direction is 0.5-5 mm; And / or, the size of the second insulating portion (22) along the second direction is 0.5-20 mm.

8. The pole piece according to claim 6, characterized in that: The insulating member (20) is a trapezoidal film layer, located in the insulating member (20) at the winding head end, and the size of the second insulating portion (22) gradually decreases along the second direction in a direction from the winding head end to the winding tail end; In the insulating member (20) located at the winding tail end, the size of the second insulating portion (22) along the second direction gradually increases along the direction from the winding head end to the winding tail end.

9. The pole piece according to claim 8, characterized in that: The insulating member (20) has a size of 100-500 mm along the first direction; And / or, the dimension of the first insulating portion (21) along the second direction is 0.5-5 mm; And / or, the maximum dimension of the second insulating portion (22) along the second direction is less than or equal to 20 mm, and the minimum dimension of the second insulating portion (22) along the second direction is greater than or equal to 0.5 mm.

10. The pole piece according to any one of claims 1 to 4, characterized in that: The pole piece body (10) further includes a pole ear (111), and the current collector (11) includes a first end and a second end arranged opposite to each other along the second direction, and the first end is connected to the pole ear (111); The insulating member (20) covering the second end includes a third insulating portion (23) and a fourth insulating portion (24), the third insulating portion (23) covering a portion of the active material layer (12), and the fourth insulating portion (24) extending out of the current collector (11) along the second direction; Alternatively, the insulating member (20) covering the second end only covers the active material layer (12).

11. The pole piece according to claim 10, characterized in that: The size of the fourth insulating portion (24) along the second direction is 0-2 mm.

12. The pole piece according to any one of claims 1 to 4, characterized in that: The insulating member (20) is an adhesive tape.

13. The pole piece according to any one of claims 1 to 4, characterized in that: The insulating member (20) and the active material layer (12) have different colors.

14. The pole piece according to any one of claims 1 to 4, characterized in that: The active material layer (12) is provided on both sides of the current collector (11) in the thickness direction, and the insulating parts (20) on the active material layers (12) on both sides are correspondingly provided.

15. The pole piece according to any one of claims 1 to 4, characterized in that: A marking portion (112) is provided on the pole piece body (10).

16. The pole piece according to claim 15, characterized in that: The marking portion (112) is a marking hole; Alternatively, the marking portion (112) is a marking mark; Alternatively, the color of the marking portion (112) is different from the color of the pole piece body (10) where it is located.

17. The pole piece according to claim 15, characterized in that: The pole piece body (10) further includes a pole lug (111), and the pole lug (111) is connected to a side edge of the current collector (11) along the second direction. A plurality of pole lugs (111) are arranged along the first direction, and the marking portion (112) is provided on the first pole lug (111) in a direction from the winding head end to the winding tail end.

18. A winding core, characterized in that: The invention comprises a positive electrode sheet (100), a separator (300) and a negative electrode sheet (200) which are stacked together, wherein the positive electrode sheet (100) is the sheet according to any one of claims 1 to 17, and the second direction is the axial direction of the winding core.

19. The winding core according to claim 18, characterized in that The negative electrode plate (200) includes a fifth edge (201) and a sixth edge (202) arranged opposite to each other along the second direction, the insulating member (20) includes a first edge (20a) and a third edge (20c) arranged opposite to each other along the second direction, the third edge (20c) is located on the active material layer (12), and the projection of the fifth edge (201) along the stacking direction is located on the side of the first edge (20a) away from the third edge (20c).

20. The winding core according to claim 18, wherein: The negative electrode plate (200) includes a fifth edge (201) and a sixth edge (202) arranged opposite to each other along the second direction; the insulating member (20) includes a first edge (20a) and a third edge (20c) arranged opposite to each other along the second direction; the third edge (20c) is located on the active material layer (12); and the projection of the fifth edge (201) along the stacking direction coincides with the first edge (20a).

21. The winding core according to claim 18, wherein: The negative electrode plate (200) includes a fifth edge (201) and a sixth edge (202) arranged opposite to each other along the second direction; the insulating member (20) includes a first edge (20a) and a third edge (20c) arranged opposite to each other along the second direction; the third edge (20c) is located on the active material layer (12); and the projection of the fifth edge (201) along the stacking direction is respectively located between the first edge (20a) and the third edge (20c).

22. The winding core according to any one of claims 19 to 21, characterized in that The fifth edge (201) and the third edge (20c) have a distance OH1 along the second direction, and the sixth edge (202) and the third edge (20c) have a distance OH2 along the second direction, wherein OH1 is greater than or equal to OH2.

23. The winding core according to claim 22, characterized in that 1.5mm≤OH1≤21mm; and / or, 1.3mm≤OH2≤21mm.

24. The winding core according to claim 23, characterized in that 0≤OH1-OH2≤2mm.

25. An electrical device, characterized in that: Comprising the winding core according to any one of claims 18-24.

26. A method for manufacturing a winding core, characterized in that: For manufacturing a winding core according to any one of claims 18 to 24, the manufacturing method of the winding core comprises: A positive electrode sheet (100) is prepared, whereby the active material layer (12) at the winding head end and / or the winding tail end of the positive electrode sheet (100) is covered with an insulating member (20); The negative electrode sheet (200), the separator (300) and the positive electrode sheet (100) are stacked in sequence and wound into a winding core along the second direction as an axis.

27. The method for manufacturing a winding core according to claim 26, wherein: The preparation of the positive electrode plate (100) includes: Unwinding the pole piece coil (400); Identifying a marking portion (112) on the electrode coil (400) to obtain the position of the attachment position d and the position of the cutting line c on the electrode coil (400), wherein a portion of the cutting line c is located within the attachment position d; Attaching an insulating layer to the attachment position d; The electrode sheet coil (400) and the insulating layer are cut along the cutting line c to obtain the positive electrode sheet (100) with the insulating member (20) attached to the winding head end and / or the winding tail end.

28. The method for manufacturing a winding core according to claim 26, wherein: The preparation of the positive electrode plate (100) includes: Unwinding the pole piece coil (400); Identifying a marking portion (112) on the electrode sheet coil (400) to obtain a position of a cutting line c on the electrode sheet coil (400); Cutting the pole piece coil (400) along the cutting line c to obtain a pole piece body (10); The insulating member (20) is attached to the winding head end and / or the winding tail end of the pole piece body (10).

29. The method for manufacturing a winding core according to any one of claims 26 to 28, characterized in that: The manufacturing method of the winding core further includes: The edges of the tab side and the non-tab side of the winding core are identified to detect whether the size difference between the positive electrode sheet (100) and the negative electrode sheet (200) is within a preset range.

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