Battery pole piece, naked battery cell and battery

Abstract

The utility model provides a battery pole piece, a naked battery cell and a battery, the battery pole piece comprises a current collecting substrate, the current collecting substrate is provided with a coating area, a blank area and a compensation area; the blank area is located on at least one side of the coating area, and the compensation area is located between the coating area and the blank area; the active layer is arranged on the plate face of the current collecting base body in a covering mode, and the active layer continuously covers the coating area and at least part of the compensation area; in the current collecting substrate, the thickness of the compensation area is larger than that of the coating area, so that the height difference b between the edge surface, located in the compensation area, of the active layer and the surface, located in the coating area, of the active layer is smaller than the thickness a, located in the coating area, of the active layer. According to the battery pole piece, the bare battery cell and the battery provided by the utility model, the compensation region can improve the height of the edge region with relatively small thickness of the active layer, so that the height difference between the edge surface and the middle surface of the active layer is reduced, the service life of the bare battery cell formed by the invention is favorably prolonged, and the problem of local deformation is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of energy storage, and in particular to a battery pole piece, a bare battery cell and a battery. BACKGROUND

[0002] In the lithium battery industry, a battery includes a bare battery cell (or a winding body) wound by a plurality of battery pole pieces and a separator. The plurality of battery pole pieces can be used as positive pole pieces and negative pole pieces of the bare battery cell respectively. In the bare battery cell, the positive pole piece, the separator and the negative pole piece are stacked, and the separator is located between the positive pole piece and the negative pole piece.

[0003] Part of the area of the battery pole piece is coated with an active layer to form a cell body of the bare battery cell. In the related art, the area of the battery pole piece coated with the active layer can have a non-uniform thickness, which not only reduces the service life of the bare battery cell, but also causes local deformation of the bare battery cell. CONTENT OF THE UTILITY MODEL

[0004] Therefore, the present application aims to provide a battery pole piece, a bare battery cell and a battery to at least partially solve the quality problem of the bare battery cell caused by the inconsistent thickness of the area of the battery pole piece coated with the active layer.

[0005] To achieve the above purpose, the first aspect of the present application provides a battery pole piece, comprising: a current collecting substrate, which has a coated area, a blank area and a compensation area along a first direction parallel to the plate surface of the current collecting substrate; the blank area is located at least on one side of the coated area, and the compensation area is located between the coated area and the blank area; an active layer is arranged on the plate surface of the current collecting substrate, and the active layer continuously covers the coated area and at least part of the compensation area; in the current collecting substrate, the thickness of the compensation area is greater than the thickness of the coated area, so that the height difference b between the edge surface of the active layer located in the compensation area and the surface of the coated area is less than the thickness a of the active layer located in the coated area.

[0006] Optionally, the current collecting substrate is provided with a round chamfer at the connection between the compensation area and the blank area, and at the connection between the compensation area and the coated area.

[0007] Optionally, along the first direction, the thickness of the compensation area of the current collecting substrate gradually increases from the coated area to the blank area.

[0008] Optionally, the thickness of the blank area of the current collecting substrate is greater than the thickness of the compensation area, and the thickness of the coated area of the battery pole piece is greater than the thickness of the blank area.

[0009] Optionally, the surface of the active layer of the coating region is located in the same plane.

[0010] Based on the same inventive concept, the second aspect of the present application further provides a bare battery cell, comprising a positive electrode sheet, a negative electrode sheet and a separator, at least one of the positive electrode sheet and the negative electrode sheet being the battery electrode sheet as described in the first aspect.

[0011] Optionally, the positive electrode sheet and the negative electrode sheet are both the battery electrode sheet, the maximum thickness difference of the compensation region and the coating region of the current collector substrate is defined as a first thickness difference, the first thickness difference of the positive electrode sheet is 5-15 microns, and the first thickness difference of the negative electrode sheet is 2-10 microns.

[0012] Optionally, the size of the compensation region along the first direction is defined as the width of the compensation region; the width e of the compensation region of the negative electrode sheet is greater than the width f of the compensation region of the positive electrode sheet, and along the thickness direction of the separator, the compensation region of the negative electrode sheet and the compensation region of the positive electrode sheet at least partially overlap in the orthogonal projection of the separator.

[0013] Optionally, an auxiliary conductive layer is arranged between the current collector substrate of the positive electrode sheet and the active layer, and along the thickness direction of the current collector substrate of the positive electrode sheet, the orthogonal projection of the active layer on the current collector substrate of the positive electrode sheet is located within the orthogonal projection of the auxiliary conductive layer on the current collector substrate of the positive electrode sheet.

[0014] Based on the same inventive concept, the third aspect of the present application further provides a battery comprising the bare battery cell as described in the second aspect.

[0015] As can be seen from the above, the battery electrode sheet, the bare battery cell and the battery provided by the present application set a compensation region between the blank region and the coating region of the current collector substrate, the compensation region corresponds to the edge of the active layer, and the coating region corresponds to the middle part of the active layer. Since the thickness of the compensation region is greater than the thickness of the coating region, the compensation region can increase the height of the edge region of the active layer with smaller thickness, thereby reducing the height difference between the edge surface and the middle surface of the active layer. When the battery electrode sheet of the present application is wound, the height difference between the various positions on the surface of the active layer is small, and the gap between the surface of the active layer and the adjacent surface is also uniform, which helps to improve the adhesion effect between the whole active layer and the adjacent surface, reduce polarization, and improve the problem of purple spots on the surface of the negative electrode sheet of the bare battery cell formed by the battery electrode sheet of the present application. At the same time, the stress of the battery electrode sheet during winding is also uniform, which can avoid stress concentration, so that the formed bare battery cell is not prone to deformation, which helps to improve the manufacturability and product yield. BRIEF DESCRIPTION OF DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the application or the related art, the following will briefly introduce the drawings needed to be used in the embodiments or the related art description. Obviously, the drawings in the following description are only the embodiments of the application, and for those skilled in the art, other drawings can also be obtained without creative labor.

[0017] Figure 1 A partial schematic view of a first battery pole piece of an embodiment of the application;

[0018] Figure 2 A schematic view of a second battery pole piece of an embodiment of the application;

[0019] Figure 3 A schematic view of a part of a bare battery core of an embodiment of the application;

[0020] Figure 4 A schematic view of Figure 3 A cross-sectional view of the middle B-B section.

[0021] Explanation of reference signs:

[0022] 100, current collecting substrate; 100a, current collecting substrate of the positive pole piece; 100b, current collecting substrate of the negative pole piece; 110, coating area; 110a, coating area of the positive pole piece; 110b, coating area of the negative pole piece; 120, blank area; 120a, blank area of the positive pole piece; 120b, blank area of the negative pole piece; 130, compensation area; 130a, compensation area of the positive pole piece; 130b, compensation area of the negative pole piece; 140, first plate surface; 150, second plate surface;

[0023] 200, active layer; 300, positive pole piece; 400, negative pole piece; 500, separator; 600, auxiliary conductive layer. DETAILED DESCRIPTION

[0024] In order to make the purpose, technical solutions and advantages of the application more clear, the following will further describe the application in combination with specific embodiments and with reference to the drawings.

[0025] It should be noted that: unless otherwise specified, the relative arrangement, numerical expression and numerical value of the components set forth in these embodiments do not limit the scope of the application.

[0026] Meanwhile, it should be understood that, for the convenience of description, the sizes of the various parts shown in the drawings are not drawn in accordance with the actual proportional relationship.

[0027] The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way limiting of the application or its application or uses.

[0028] It should be noted that the technical terms or scientific terms used in the embodiments of the present application should be understood as the common meanings understood by those with ordinary skills in the art to which the embodiments of the present application belong, unless otherwise defined. The terms “first”, “second”, and similar terms used in the embodiments of the present application do not represent any order, number, or importance, but are only used to distinguish different components. The terms “include”, “contain”, and similar terms mean that the elements or objects before the terms cover the elements or objects listed after the terms and their equivalents, and do not exclude other elements or objects. The terms “connect” or “connected” and similar terms are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. The terms “upper”, “lower”, “left”, “right”, and the like only represent relative positional relationships, which can change accordingly when the absolute positions of the described objects change.

[0029] As Figure 1 , Figure 1 A partial schematic view of a first battery electrode tab is shown, which in some embodiments includes a current collecting substrate 100 (or foil). The current collecting substrate 100 can be constructed of a sheet of electrically conductive material, for example. In a first direction parallel to the plane of the current collecting substrate 100 (e.g., the X direction in FIG. 1), the current collecting substrate 100 has a membrane region 160 and a margin region 120 adjacent to the membrane region 160. The thickness of the current collecting substrate 100 is uniform, i.e., the thickness of the current collecting substrate 100 in the membrane region 160 is the same as the thickness of the current collecting substrate 100 in the margin region 120. The plane of the membrane region 160 is entirely covered with an active layer 200; whereas the plane of the margin region 120 is not covered with the active layer 200 and is entirely exposed. Figure 1

[0030] Applicants have found that the active material used to form the active layer 200 is in a flowable state (e.g., a slurry) when it is applied, which causes the active material near the margin region 120 (i.e., the active material at the edge of the membrane region 160) to deform under the influence of fluidic properties when the active material is applied in the membrane region 160. When the applied active material is dried to form the active layer 200, the thickness of the active layer 200 near the margin region 120 is reduced, as shown in FIG. 2B. Figure 1 In the membrane region 160, the area of the active layer 200 with a smaller thickness can be referred to as a thinned sub-region 161. The thinned sub-region 161 has a positive effect on the battery formed by the battery electrode tab, on the one hand, it can improve the energy density of the battery, and on the other hand, it can also improve the power characteristics of the battery.

[0031] ​However, the thinned sub-region 161 also has a negative impact. Since the thinned sub-region 161 is part of the film region 160, the thinned sub-region 161 also needs to be wound when the battery pole piece is wound. However, since the thickness of the thinned sub-region 161 is thinner than the thickness of the other sub-regions of the film region 160, the height difference between the surface of the active layer 200 in the thinned sub-region 161 and the surface of the active layer 200 in the other sub-regions is large. During winding, the gap between the surface of the thinned sub-region 161 (i.e., the surface of the active layer 200) and the adjacent surface is larger than the gap between the surface of the other sub-regions of the film region 160 and the adjacent surface. For the bare cell formed by the above battery pole piece, on the one hand, the large gap at the thinned sub-region 161 will make the bonding effect between the thinned sub-region 161 and the adjacent surface poor, the polarization will be large, and during the use of the bare cell, purple spots may appear on the surface of the negative pole piece, and the formation of the purple spots is related to the deposition of lithium metal on the surface of the pole piece. On the other hand, the large gap at the thinned sub-region 161 will also cause the problem of uneven stress of the film region 160 as a whole during winding, and the position corresponding to the thinned sub-region 161 in the bare cell is prone to deformation, thereby affecting the quality of the bare cell.

[0032] To solve the above problems, as shown in Figure 2 , Figure 2 A second battery pole piece is shown. In some embodiments, the battery pole piece includes: a current collecting substrate 100, which has a coated region 110, a blank region 120, and a compensation region 130 along a first direction (such as Figure 2 X direction in the figure), the blank region 120 is located at least one side of the coated region 110, and the compensation region 130 is located between the coated region 110 and the blank region 120; an active layer 200, which is coated on the surface of the current collecting substrate 100, and the active layer 200 continuously covers the coated region 110 and at least part of the compensation region 130; in the current collecting substrate 100, the thickness of the compensation region 130 is greater than the thickness of the coated region 110, so that the height difference b between the edge surface of the active layer 200 located in the compensation region 130 and the surface located in the coated region 110 is less than the thickness a of the active layer 200 located in the coated region 110.

[0033] For example, the blank region 120 can be located on one side of the coated region 110, or on opposite sides. As shown in Figure 2 When the blank region 120 is located on opposite sides of the coated region 110, the two blank regions 120 are symmetrical with respect to the coated region 110. Cutting the coated region 110 along the axis of symmetry can form two battery pole pieces with the same structure.

[0034] Exemplarily, the current collecting substrate 100 can be a sheet structure, and the plate surface of the current collecting substrate 100 is two opposite and large-area surfaces of the sheet structure, and the thickness direction (for example, the Z direction) of the current collecting substrate 100 is perpendicular to the plate surface. Figure 2

[0035] Exemplarily, the current collecting substrate 100 can be formed by rolling. The current collecting substrate 100 to be formed is arranged between the upper and lower compression rollers, and the current collecting substrate 100 to be formed is extruded by the two compression rollers when passing through the gap between the two compression rollers to form the current collecting substrate 100. The gap between the upper and lower compression rollers corresponding to the coating area 110 is small to form the coating area 110 with small thickness. Correspondingly, the gap between the upper and lower compression rollers corresponding to the blank area 120 is large to form the blank area 120 with large thickness.

[0036] In this embodiment, the thickness of the blank area 120 of the current collecting substrate 100 is increased to form the compensation area 130 with a thickness greater than the coating area 110 between the blank area 120 and the coating area 110. Since the thickness of the compensation area 130 is large, the plate surface of the compensation area 130 for carrying the active layer 200 is higher than the plate surface of the coating area 110 for carrying the active layer 200. Therefore, even if the thickness of the active layer 200 in the compensation area 130 is smaller than the thickness of the active layer 200 in the coating area 110, the plate surface of the compensation area 130 makes the active layer 200 located thereon to be at a higher height, that is, height compensation is formed to compensate for the thickness difference. Therefore, the structure in which b is less than a is formed to make the overall outer surface height of the active layer 200 tend to be uniform.

[0037] The battery pole piece provided in this embodiment is provided with the compensation area 130 between the blank area 120 and the coating area 110 of the current collecting substrate 100, the compensation area 130 corresponds to the edge of the active layer 200, and the coating area 110 corresponds to the middle part of the active layer 200. Since the thickness of the compensation area 130 is greater than the thickness of the coating area 110, the compensation area 130 can increase the height of the edge area of the active layer 200 with small thickness, thereby reducing the height difference between the edge surface and the middle surface of the active layer 200. When the battery pole piece of this embodiment is wound, the height difference between the various positions on the surface of the active layer 200 is small, and the gap between the surface of the active layer 200 and the adjacent surface is also uniform, which helps to improve the bonding effect between the overall active layer 200 and the adjacent surface, reduce polarization, and improve the problem of purple spots on the surface of the negative pole piece of the bare battery cell formed by the battery pole piece of this embodiment. At the same time, the stress on the battery pole piece during winding is also uniform, which can avoid stress concentration, so that the formed bare battery cell is not prone to deformation, which helps to improve the manufacturability and product yield. ​

[0038] As Figure 2 In some embodiments, the current collecting substrate 100 is provided with a round chamfer at the joint between the compensation region 130 and the blank region 120, and at the joint between the compensation region 130 and the coating region 110.

[0039] For example, when the battery pole piece is the negative pole piece 400 of the bare battery cell, the radius of the round chamfer is 2-10 microns, for example, 2 microns, 3 microns, 4 microns, 5 microns, 6 microns, 8 microns, or 10 microns.

[0040] For example, when the battery pole piece is the positive pole piece 300 of the bare battery cell, the radius of the round chamfer is 2-15 microns, for example, 2 microns, 5 microns, 8 microns, 10 microns, 12 microns, or 15 microns.

[0041] Since there may be a height difference between the surface of the compensation region 130 of the current collecting substrate 100 and the surface of the blank region 120, the presence of an edge or corner structure at the joint between the two surfaces may adversely affect the continuity and structural stability of the active layer 200, and thus adversely affect the electrical performance of the battery pole piece. To avoid the above problems, the joint between the two surfaces is provided with a round chamfer in the present embodiment, which can smoothly transition the surface of the compensation region 130 and the surface of the blank region 120, helping to ensure that the active layer 200 laid on the surface has good continuity, a stable structure, and good electrical performance.

[0042] Similarly, the current collecting substrate 100 is provided with a round chamfer at the joint between the compensation region 130 and the coating region 110, which has the same beneficial effects as the round chamfer provided at the joint between the compensation region 130 and the blank region 120, which will not be described here.

[0043] As Figure 2 In some embodiments, in the first direction, the thickness of the compensation region 130 of the current collecting substrate 100 gradually increases from the coating region 110 to the blank region 120.

[0044] For example, the thickness of the compensation region 130 continuously increases from the coating region 110 to the blank region 120, at which time the surface of the compensation region 130 of the current collecting substrate 100 is a smooth curved surface or an inclined surface; or the thickness of the compensation region 130 increases in stages, at which time the surface of the compensation region 130 of the current collecting substrate 100 is a stepped structure, and the thickness is constant in some regions.

[0045] For example, when the battery pole piece is the positive pole piece 300, and the surface of the compensation region 130 of the current collecting substrate 100 is an inclined surface, the included angle A between the inclined surface and the surface of the coating region 110 is not greater than 60°, for example, 20°, 30°, 45°, or 60°.

[0046] For example, when the battery pole piece is a negative pole piece 400, and the surface of the compensation area 130 of the current collecting substrate 100 is a slope, the included angle A between the slope and the surface of the coating area 110 is not greater than 45°, for example, 10°, 20°, 30°, or 45°.

[0047] It should be noted that when the surface of the compensation area 130 of the current collecting substrate 100 is a curved surface, the included angle A is the included angle between the tangent of the curved surface and the surface of the coating area 110.

[0048] In combination Figure 2 , the thickness of the active layer 200 gradually decreases from the middle to the edge. In order to make the surface of the compensation area 130 of the current collecting substrate 100 better compensate for the edge area of the active layer 200, the thickness of the compensation area 130 is designed to gradually increase from the coating area 110 to the blank area 120, so that the surface height change of the compensation area 130 of the current collecting substrate 100 corresponds to the thickness change of the edge area of the active layer 200, so that the surface height of the active layer 200 is more uniform.

[0049] As Figure 2 In some embodiments, the thickness of the blank area 120 of the current collecting substrate 100 is greater than the thickness of the compensation area 130, that is, the surface height of the blank area 120 of the current collecting substrate 100 is greater than the maximum surface height of the compensation area 130 of the current collecting substrate 100.

[0050] In this embodiment, the thickness of the current collecting substrate 100 of the blank area 120 is designed to be thicker, which can make the stretchability greater, and it is easier to stretch and form the blank area 120 during the forming of the current collecting substrate 100, which can reduce the risk of wrinkling and belt breaking, and help to reduce the difficulty of preparing the battery pole piece and improve the manufacturability and product rate.

[0051] The blank area 120 of the current collecting substrate 100 will form a plurality of tabs after cutting, which are spaced apart along the edge of the compensation area 130 (the edge extends in the direction perpendicular to the paper surface, that is, the Y direction). Figure 2 After the battery pole piece is wound, the plurality of tabs need to be connected with the corresponding structural member (such as a pole or a connecting piece). Since the connection surface area for connecting the tabs on the structural member is limited, when the width (Y direction size) of a single tab is large, the plurality of tabs need to be strictly aligned (that is, the alignment requirement is high) to facilitate reliable electrical connection between all the tabs and the structural member.

[0052] In the embodiment, the thickness of the current collector 100 in the blank area 120 is large, so that the width of the tab formed can be reduced to lower the dislocation requirement of the tab, while ensuring that the tab formed has a flow area meeting the process requirement. Even if there is a certain positional deviation between different tabs, it can be ensured that all the tabs can be reliably electrically connected to the corresponding structural member. Therefore, the battery tab of the embodiment helps to reduce the preparation difficulty of the battery and improve the manufacturability and product yield.

[0053] As Figure 2 In some embodiments, the thickness of the coated area 110 of the battery tab is greater than the thickness of the blank area 120, i.e., the surface height of the active layer 200 in the coated area 110 is greater than the surface height of the blank area 120 of the current collector 100.

[0054] When the battery tab is wound, the surface of the active layer 200 will be in contact with the adjacent surface. When the thickness of the coated area 110 of the battery tab is greater than the thickness of the blank area 120, it helps to avoid the contact between the blank area 120 of the current collector 100 and the adjacent surface, thereby avoiding the short circuit problem of the battery formed by the battery tab.

[0055] As Figure 2 In some embodiments, the current collector 100 includes opposite first and second plate surfaces 140 and 150, and the first and second plate surfaces 140 and 150 are symmetrically arranged with respect to the central axis of the current collector 100 along the first direction (e.g., the dotted line in the figure). Figure 3

[0056] For example, the active layer 200 applied to the first plate surface 140 and the active layer 200 applied to the second plate surface 150 are symmetrically arranged along the central axis of the first direction.

[0057] Since the current collector 100 has active layers 200 applied on both sides, the structures of the first and second plate surfaces 140 and 150 are the same, so that the active layers 200 on both sides of the current collector 100 have the beneficial effects described above, and the battery tab can be more uniformly stressed when wound, further improving the product yield of the bare battery cell formed by the battery tab.

[0058] As Figure 3 In some embodiments, the surfaces of the active layers 200 in the coated area 110 are located in the same plane.

[0059] ​In combination with the foregoing, the higher the consistency of the surface height of each region of the active layer 200, the more uniform the stress on the battery electrode during winding. Most of the active layer 200 is located in the coating region 110, and when the surfaces of the active layer 200 laid in the coating region 110 are located in the same plane, the consistency of the surface height of each region of the active layer 200 can be effectively improved, which helps to reduce the risk of deformation of the battery electrode due to stress concentration during winding.

[0060] Based on the same inventive concept, in combination with the description of the battery electrode of each of the above embodiments, the present embodiment provides a bare battery cell, which has the corresponding technical effects of the battery electrode of each of the above embodiments, which will not be described here again.

[0061] As Figure 3 , Figure 4 The present embodiment provides a bare battery cell, which includes a positive electrode 300, a negative electrode 400, and a separator 500. At least one of the positive electrode 300 and the negative electrode 400 is a battery electrode as described in each of the above embodiments.

[0062] For example, taking the positive electrode 300 as an example, along the first direction, the edge of the separator 500 can extend beyond the edge of the compensation region 130a of the positive electrode close to the blank region 120a of the positive electrode, and not extend beyond the edge of the blank region 120a of the positive electrode away from the compensation region 130a of the positive electrode, so as to ensure that the separator 500 can reliably separate the positive electrode 300 and the negative electrode 400, and will not block the positive electrode tab of the positive electrode.

[0063] It should be noted that the relative positional relationship between the separator 500 and the blank region 120b of the negative electrode is the same as the relative positional relationship between the separator 500 and the blank region 120a of the positive electrode described above, which will not be described here again.

[0064] As Figure 4 The separator 500 is located between the positive electrode 300 and the negative electrode 400, the positive projection of the positive electrode tab formed by the current collector substrate 100a of the positive electrode along the thickness direction of the separator 500 does not coincide with the negative projection of the negative electrode tab formed by the current collector substrate 100b of the negative electrode, and the positive electrode tab and the negative electrode tab can be located on the same side or opposite sides of the bare battery cell.

[0065] As Figure 3 , Figure 4 The present embodiment provides a bare battery cell, which includes a positive electrode 300, a negative electrode 400, and a separator 500. At least one of the positive electrode 300 and the negative electrode 400 is a battery electrode as described in each of the above embodiments. Figure 4Fig. 6 is a schematic view of a cross section of a B-B section, in some embodiments, an auxiliary conductive layer 600 is arranged between the current collector substrate 100a and the active layer 200 of the positive electrode sheet, and the positive projection of the active layer 200 on the current collector substrate 100a of the positive electrode sheet is within the positive projection of the auxiliary conductive layer 600 on the current collector substrate 100a of the positive electrode sheet along the thickness direction of the current collector substrate 100a of the positive electrode sheet.

[0066] For example, the auxiliary conductive layer 600 can be a carbon coating layer coated on the surface of the current collector substrate 100a of the positive electrode sheet.

[0067] The auxiliary conductive layer 600 arranged on the surface of the current collector substrate 100a of the positive electrode sheet helps to increase the contact area between the active layer 200 and the current collector substrate 100a of the positive electrode sheet, increase the adhesion between the two, reduce the contact resistance between the two, and help to improve the conductivity of the positive electrode sheet 300. At the same time, the auxiliary conductive layer 600 can also protect the current collector substrate 100a of the positive electrode sheet, reduce the corrosion of the electrolyte on the current collector substrate 100a of the positive electrode sheet, and increase the cycle life of the positive electrode sheet 300.

[0068] As Figure 4 The positive electrode sheet 300 and the negative electrode sheet 400 are both battery electrode sheets, and the maximum thickness difference (i.e., the difference between c and d) of the compensation region 130 and the coating region 110 of the current collector substrate 100 is defined as a first thickness difference. The first thickness difference of the positive electrode sheet 300 is 5 microns to 15 microns, and the first thickness difference of the negative electrode sheet 400 is 2 microns to 10 microns.

[0069] For the positive electrode sheet 300:

[0070] For example, the thickness of the coating region 110a of the positive electrode sheet is 10 microns to 17 microns, such as 10 microns, 11 microns, 12 microns, 13 microns, 14 microns, 15 microns, 16 microns, or 17 microns.

[0071] For example, the thickness of the single-sided active layer 200 of the positive electrode sheet is 60 microns to 125 microns, such as 60 microns, 70 microns, 80 microns, 90 microns, 100 microns, 110 microns, 115 microns, 120 microns, or 125 microns.

[0072] For example, the first thickness difference of the positive electrode sheet 300 can be 5 microns, 7 microns, 10 microns, 12 microns, or 15 microns.

[0073] Based on the thickness of the coated area 110a of the positive electrode sheet and the thickness of the single-sided active layer 200, this embodiment designs the first thickness difference of the positive electrode sheet 300 to be 5 to 15 microns. When the first thickness difference is within this range, it can ensure that the compensation area 130a of the positive electrode sheet can effectively compensate for the height of the edge of the active layer 200, and it can also ensure that the surface of the active layer 200 in the coated area 110a of the positive electrode sheet is higher than the surface of the blank area 120a of the positive electrode sheet, thereby preventing short circuits in the bare battery cell during use.

[0074] For negative plate 400:

[0075] Illustratively, the thickness of the coating region 110 b of the negative electrode sheet is 4 μm to 7 μm, for example, 4 μm, 5 μm, 6 μm, or 7 μm.

[0076] Illustratively, the thickness of the active layer 200 on one side of the negative electrode sheet is 40 micrometers to 90 micrometers, for example, 40 micrometers, 50 micrometers, 60 micrometers, 70 micrometers, 80 micrometers, or 90 micrometers.

[0077] For example, the first thickness difference of the negative electrode sheet 400 may be 2 micrometers, 4 micrometers, 5 micrometers, 8 micrometers, or 10 micrometers.

[0078] Based on the thickness of the coating region 110 b of the negative electrode sheet and the thickness of the single-sided active layer 200 , in this embodiment, the first thickness difference of the negative electrode sheet 400 is designed to be 2 μm to 10 μm.

[0079] The beneficial effects of the first thickness difference of the negative electrode sheet 400 being within the above range are the same as the beneficial effects of the first thickness difference of the positive electrode sheet 300 being within the corresponding range, and are not further described here.

[0080] like ​ In some embodiments, the size of the compensation region 130 along the first direction is defined as the width of the compensation region 130; the width e of the compensation region 130b of the negative electrode sheet is greater than the width f of the compensation region 130a of the positive electrode sheet, and the compensation region 130b of the negative electrode sheet is greater than the width f of the compensation region 130a of the positive electrode sheet, and the compensation region 130b of the negative electrode sheet is greater than the width e of the compensation region 130b of the positive electrode sheet, and the compensation region 130b of the negative electrode sheet is greater than the width f of the compensation region 130a ... ​ In the Z direction), the orthographic projections of the compensation region 130b of the negative electrode sheet and the compensation region 130a of the positive electrode sheet on the diaphragm 500 at least partially overlap.

[0081] Illustratively, the difference between the width e of the compensation region 130b of the negative electrode sheet and the width f of the compensation region 130a of the positive electrode sheet is 3 mm to 15 mm, for example, 3 mm, 5 mm, 8 mm, 10 mm, 12 mm or 15 mm.

[0082] The active layer 200 is formed by drying the slurry coated on the surface of the current collecting substrate 100, and the width of the compensation area 130 can be specifically designed according to at least the performance (for example, the flow performance) of the slurry and the first thickness difference, so that the current collecting substrate 100 of the compensation area 130 can effectively compensate the edge of the active layer 200.

[0083] Meanwhile, since there is a thickness difference between the compensation area 130 and the coating area 110 of the current collecting substrate 100, designing the width of the compensation area 130 within a reasonable range also helps to improve the structural stability of the current collecting substrate 100, avoiding the problem of the current collecting substrate 100 breaking when the blank area 120 of the current collecting substrate 100 is bent (for example, bare cell welding or core combining process).

[0084] The compensation area 130b of the negative electrode sheet and the compensation area 130a of the positive electrode sheet at least partially overlap in the orthographic projection of the diaphragm 500, that is, the compensation areas 130 of both the positive electrode sheet 300 and the negative electrode sheet 400 are arranged on the same side of the bare cell. Correspondingly, the positive electrode tab and the negative electrode tab of the bare cell are also located on the same side, facilitating the welding between the two tabs and the cover plate assembly (for example, the pole or the connecting sheet), and being conducive to reducing the assembly difficulty of the battery using the bare cell of the embodiment.

[0085] Based on the same inventive concept, in combination with the description of the bare cell of each of the above embodiments, the present embodiment provides a battery having the corresponding technical effects of the bare cell of each of the above embodiments, which will not be described here.

[0086] A battery comprising the bare cell as described in each of the above embodiments.

[0087] It should be noted that the above describes some embodiments of the present application. Other embodiments are within the scope of the appended claims. In some cases, the actions or steps recited in the claims can be performed in an order different than that described in the above embodiments and still achieve the desired result. In addition, the processes depicted in the figures do not necessarily require the particular order shown or sequential order to achieve the desired results. In certain implementations, multitasking and parallel processing can be advantageous or possible.

[0088] Each of the embodiments in the present application is described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the embodiments can be mutually referred to.

[0089] The description of the application is presented for purposes of illustration and description, and not by limitation. Numerous modifications and variations on the embodiments described herein will be apparent to those of ordinary skill in the art in light of the foregoing description. The embodiments are chosen and described in order to best explain the principles of the application and its practical application to thereby enable others skilled in the art to best utilize the application. Various embodiments of the application are contemplated and can be made without departing from the spirit or scope of the application.

[0090] It should be understood that any of the above-described embodiments can be implemented in the form of control logic using hardware (e.g. an application specific integrated circuit or field programmable gate array) or a combination of hardware and software (e.g. software running on a processor or microprocessor). The software can be software stored in a computer readable storage medium such as RAM (random access memory) or ROM, for example, erasable programmable ROM, electrically erasable programmable ROM, flash memory or the like.

[0091] Although the application has been described in conjunction with specific embodiments thereof, numerous alternatives, modifications, and variations will be readily apparent to those of ordinary skill in the art. Such alternatives, modifications, and variations are intended to fall within the ambit of the present application.

[0092] It is therefore intended that the application be interpreted as including all such alternatives, modifications and variations that fall within the scope of the application. Accordingly, although specific embodiments have been illustrated and described herein, it should be appreciated that any arrangement calculated to achieve the same or similar results could be substituted for the specific embodiments shown. This application is intended to cover any adaptations or variations of the present application. Therefore, it is intended that the application be construed as including all such adaptations and variations as fall within the scope of the appended claims and their equivalents.

Claims

1. A battery pole piece, characterized by, The battery pole piece comprises: a current collecting substrate having a coated area, a blank area and a compensation area along a first direction parallel to a plate surface of the current collecting substrate, the blank area being located at least on one side of the coated area, and the compensation area being located between the coated area and the blank area; an active layer coated on the plate surface of the current collecting substrate, and the active layer continuously covering the coated area and at least part of the compensation area; in the current collecting substrate, a thickness of the compensation area is greater than a thickness of the coated area, so that a height difference b between an edge surface of the compensation area and a surface of the coated area of the active layer is less than a thickness a of the coated area of the active layer.

2. The battery pole piece of claim 1, wherein, The current collecting substrate is provided with a round chamfer at a junction of the compensation area and the blank area, and at a junction of the compensation area and the coated area.

3. The battery pole piece of claim 1, wherein, Along the first direction, the thickness of the compensation area of the current collecting substrate gradually increases from the coated area to the blank area.

4. The battery pole piece of claim 1, wherein, The thickness of the blank area of the current collecting substrate is greater than the thickness of the compensation area, and the thickness of the coated area of the battery pole piece is greater than the thickness of the blank area.

5. The battery pole piece of claim 1, wherein, The surfaces of the active layer of the coated area are located in the same plane.

6. A bare cell characterized by, The battery pole piece comprises a positive pole piece, a negative pole piece and a separator, at least one of the positive pole piece and the negative pole piece being the battery pole piece as claimed in any one of claims 1 to 5.

7. The bare cell of claim 6, wherein, Both the positive pole piece and the negative pole piece are the battery pole piece, a maximum thickness difference of the compensation area and the coated area of the current collecting substrate is defined as a first thickness difference, the first thickness difference of the positive pole piece is 5 microns to 15 microns, and the first thickness difference of the negative pole piece is 2 microns to 10 microns.

8. The bare cell of claim 6, wherein, A size of the compensation area along the first direction is defined as a width of the compensation area. The width e of the compensation area of the negative pole piece is greater than the width f of the compensation area of the positive pole piece, and along a thickness direction of the separator, a positive projection of the compensation area of the negative pole piece and a positive projection of the compensation area of the positive pole piece at least partially overlap.

9. The bare cell of claim 6, wherein, An auxiliary conductive layer is arranged between the current collecting substrate and the active layer of the positive pole piece, and along a thickness direction of the current collecting substrate of the positive pole piece, a positive projection of the active layer on the current collecting substrate of the positive pole piece is located within a positive projection of the auxiliary conductive layer on the current collecting substrate of the positive pole piece.

10. A battery, characterized by The bare battery cell comprises the battery pole piece as claimed in any one of claims 6 to 9.

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