Pole piece, battery cell and battery

Abstract

The utility model relates to the technical field of batteries, and discloses a pole piece, a battery cell and a battery, the pole piece is provided with a plurality of first holes, the pole piece comprises a base body and a pole lug, and the pole lug is connected to the base body; wherein the plurality of first holes comprise central holes, and the central holes are formed in the connecting positions of the tabs and the base body; a plurality of reference arcs concentric with the center hole are defined, the reference arcs are distributed on the outer side of the center hole, and the diameters of the reference arcs are gradually increased from the inner side of the center hole to the outer side of the center hole; and the rest of the first holes except the central hole are uniformly distributed on the plurality of reference arcs and are all arranged on the base body, so that the condition of lithium precipitation in an area near the tab can be improved.

Description

Technical Field

[0001] The utility model relates to the technical field of batteries, and in particular to a pole piece, a battery core and a battery. Background Art

[0002] Lithium batteries are widely used in consumer electronics, power tools, electric vehicles and other fields due to their high energy density and long life.

[0003] Based on the structural design of the lithium battery itself, the current will pass through the tabs during charging and discharging. The area near the tabs has a higher current density and a significantly higher temperature rise than other areas, making lithium deposition more likely to occur. Utility Model Content

[0004] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, the present invention provides a pole piece that can improve the lithium deposition in the vicinity of the pole tab.

[0005] The utility model also provides a battery cell and a battery having the above-mentioned electrode piece.

[0006] According to the pole piece of the embodiment of the first aspect of the present invention, the pole piece is provided with a plurality of first holes, and the pole piece includes a base and a pole ear, and the pole ear is connected to the base; wherein the plurality of first holes includes a center hole, and the center hole is provided at the connection position of the pole ear and the base; a plurality of reference arcs concentric with the center hole are defined, and the plurality of reference arcs are distributed on the outside of the center hole, and the diameter gradually increases from the inside to the outside of the center hole; the remaining first holes except the center hole are distributed on the plurality of reference arcs, and are all provided on the base.

[0007] According to the pole piece of the embodiment of the present invention, there are at least the following beneficial effects: the pole piece is provided with a plurality of first holes, the plurality of first holes include a central hole located at the connection position of the pole ear and the base body, and the remaining first holes except the central hole are distributed on a plurality of reference arcs outside the central hole, and are all provided on the base body. In this way, a plurality of first holes are provided in the area near the pole ear, which helps to optimize the distribution of current in the area near the pole ear, reduce the lithium ion deintercalation rate and total amount near the pole ear, and can also increase the contact area between the electrolyte and the pole piece, improve the infiltration effect of the electrolyte in the area near the pole ear, thereby reducing the temperature rise of the pole ear, improving the lithium deposition in the area near the pole ear, and reducing the thermal runaway in the area near the pole ear. Moreover, the plurality of first holes are distributed on a plurality of reference arcs, which can optimize the distribution of the first holes on the base body, further optimize the distribution of current, and help determine the punching positions of the plurality of first holes, thereby improving the punching efficiency.

[0008] According to some embodiments of the present invention, the multiple reference arcs include adjacent first arcs and second arcs, the first arc is located on the inner side of the second arc; the hole spacing between two adjacent first holes located on the first arc is equal to the radius difference between the first arc and the second arc.

[0009] According to some embodiments of the present invention, the pole piece has a length direction and a width direction, and the pole ear is connected to one side of the substrate along the width direction; the radius of the reference arc is defined as r, the diameter of the first hole is d, the length of the pole ear is w, the width of the substrate is a, and the hole spacing between adjacent first holes on the same reference arc is L; the pole piece is applied to a wound battery cell, and the substrate includes straight sections and bent sections alternately distributed along the length direction; after the pole piece is wound, a plurality of straight sections are stacked, and the pole ear is connected to the straight section, and the minimum distance between the length center line of the pole ear and the side of the straight section along the width direction is c, and the length of the straight section is b, or, the pole piece is applied to a laminated battery cell, the minimum distance between the length center line of the pole ear and the side of the substrate along the width direction is c, and the length of the substrate is b; wherein, when , the number of the first holes located on the reference arc is ;when , the number of the first holes located on the reference arc is ;when , the number of the first holes located on the reference arc is ; and / or, when 0.5d<r≤0.5w, the hole spacing between adjacent first holes located on the reference arc is L; when 0.5w<r<0.5a, the hole spacing between adjacent first holes located on the reference arc is H, ; If the electrode is a negative electrode, 0.5mm≤L≤1mm, 0.5≤k≤2; above it, if the electrode is a positive electrode, 0.5mm≤L≤2mm, 0.6≤k≤3.

[0010] According to some embodiments of the present invention, the pole piece has a length direction and a width direction, the pole tab is connected to one side of the substrate along the width direction; the center of the center hole is located on the length center line of the pole tab along the length direction.

[0011] According to some embodiments of the present invention, the distribution density of the first holes decreases from close to the central hole to away from the central hole.

[0012] According to some embodiments of the present invention, the depth of the first hole is greater than or equal to 40% of the thickness of the substrate; and / or, if the electrode is a negative electrode, the diameter of the first hole is greater than or equal to 50 μm and less than or equal to 500 μm; if the electrode is a positive electrode, the diameter of the first hole is greater than or equal to 500 μm and less than or equal to 2000 μm; and / or, the substrate includes a current collector and an active material coating coated on the surface of the current collector, and the loss percentage of the active material coating is A. If the electrode is a negative electrode, 0.5%≤A≤4%; if the electrode is a positive electrode, 1%≤A≤10%.

[0013] According to some embodiments of the present invention, the base includes straight sections and bent sections alternately distributed along the width direction; after the pole piece is wound, multiple straight sections are stacked, and the bent sections are provided with multiple second holes.

[0014] According to some embodiments of the present invention, if the electrode piece is a negative electrode piece, the diameter of the second hole is greater than or equal to 50 μm and less than or equal to 300 μm; if the electrode piece is a positive electrode piece, the diameter of the second hole is greater than or equal to 500 μm and less than or equal to 2000 μm; and / or, if the electrode piece is a negative electrode piece, the hole depth of the second hole is greater than or equal to 40% of the thickness of the substrate and less than or equal to 80% of the thickness of the substrate; if the electrode piece is a positive electrode piece, the hole depth of the second hole is greater than or equal to 30% of the thickness of the substrate; and / or, if the electrode piece is a negative electrode piece, the hole spacing between two adjacent second holes is greater than or equal to 0.4 mm and less than or equal to 2 mm; if the electrode piece is a positive electrode piece, the hole spacing between two adjacent second holes is greater than or equal to 1 mm and less than or equal to 5 mm.

[0015] According to an embodiment of the second aspect of the present utility model, the battery cell includes a first pole piece and a second pole piece, wherein at least one of the first pole piece and the second pole piece is the pole piece in any of the above embodiments.

[0016] According to the battery of the third embodiment of the present utility model, the battery includes the battery cell in the above embodiment.

[0017] Additional aspects and advantages of the present invention will be given in part in the following description and will become apparent from the following description or learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The present invention will be further described below with reference to the accompanying drawings and embodiments, wherein:

[0019] Figure 1 A schematic structural diagram of a laminated battery cell provided by an embodiment of the present utility model is shown;

[0020] Figure 2 The structure diagram of the wound battery cell provided by the embodiment of the present utility model is shown;

[0021] Figure 3 Shown Figure 1 Schematic diagram of the structure of the pole piece of the medium-laminated battery cell;

[0022] Figure 4 Shown Figure 2 Schematic diagram of the structure of the pole piece of the mid-wound battery cell;

[0023] Figure 5 Shown Figure 2 Another structural diagram of the pole piece of the wound battery cell;

[0024] Figure 6 Shown Figure 2 Schematic diagram of the partial cross-section structure of the mid-wound battery cell.

[0025] Reference numerals:

[0026] Battery cell 100;

[0027] Pole piece 110; positive electrode piece 150; negative electrode piece 170; separator 130; positive electrode tab 190; negative electrode tab 210; corner 230;

[0028] Base 111; straight section 1111; bent section 1113; second hole 1115;

[0029] Tab 113; length centerline 1131; connection position 115; reference line 1151;

[0030] First hole 117; center hole 1171; reference arc 119;

[0031] Length direction Y; width direction Z. DETAILED DESCRIPTION

[0032] The following describes embodiments of the present invention in detail. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended only to explain the present invention and are not to be construed as limiting the present invention.

[0033] In the description of the present invention, it should be understood that descriptions involving orientations, such as up, down, front, back, left, right, etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, they cannot be understood as limitations on the present invention.

[0034] In the description of this utility model, "several" means more than one, "plurality" means more than two, "greater than," "less than," and "exceed" are understood to exclude the number itself, while "above," "below," and "within" are understood to include the number itself. The use of the terms "first" and "second" is solely for the purpose of distinguishing technical features and is not to be construed as indicating or implying relative importance, implicitly specifying the number of the indicated technical features, or implicitly specifying the order of the indicated technical features.

[0035] In the description of the present invention, unless otherwise clearly defined, terms such as setting, installing, and connecting should be understood in a broad sense, and technicians in the relevant technical field can reasonably determine the specific meanings of the above terms in the present invention based on the specific content of the technical solution.

[0036] In the description of the present invention, reference to terms such as "one embodiment," "some embodiments," "illustrative embodiments," "examples," "specific examples," or "some examples" means that the specific features, structures, materials, or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the exemplary expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0037] See also Figures 1 to 2 , an embodiment of the present application provides a battery that can be used to provide power for new energy vehicles, electronic equipment or other equipment.

[0038] The battery includes a shell and a battery cell 100 , and the battery cell 100 can be accommodated in the shell.

[0039] In some embodiments, the battery cell 100 may be a wound battery cell, or the battery cell 100 may be a laminated battery cell.

[0040] In some embodiments, the battery cell 100 includes a first electrode piece and a second electrode piece.

[0041] One of the first electrode sheet and the second electrode sheet may be a positive electrode sheet 150 , and the other may be a negative electrode sheet 170 .

[0042] It is understandable that the battery cell 100 may further include a diaphragm 130 , and the diaphragm 130 may be disposed between the first electrode piece and the second electrode piece.

[0043] As an example, when the battery cell 100 is a laminated battery cell (such as Figure 1 As shown), the first electrode piece, the diaphragm 130 and the second electrode piece can be stacked in sequence to form a laminated battery cell. For details, please refer to the existing technology and will not be repeated here.

[0044] As another example, when the battery cell 100 is a wound battery cell (eg Figure 2 and Figure 6 As shown in FIG, the first electrode sheet, the diaphragm 130 and the second electrode sheet can be stacked in sequence and then wound to form a battery cell 100. For details, reference can be made to the prior art and will not be repeated here.

[0045] See also Figures 3 and 4 In some embodiments, the electrode piece 110 may have a length direction Y and a width direction Z. When the battery cell 100 is a wound battery cell, the electrode piece 110 may be wound along the length direction Y to form a wound battery cell.

[0046] In some embodiments, the pole piece 110 includes a base 111 and a pole tab 113 .

[0047] The electrode 110 may refer to the first electrode or the second electrode, that is, the electrode 110 may be the negative electrode 170 or the positive electrode 150 .

[0048] The tab 113 is connected to the base 111 . For example, the tab 113 may be connected to one side of the base 111 along the width direction Z.

[0049] As an example, when the battery cell 100 is a wound battery cell (such as Figure 2 and Figure 4 As shown), the base 111 may include straight sections 1111 and bent sections 1113 alternately distributed along the length direction Y, and there may be multiple straight sections 1111 and bent sections 1113. After the electrode 110 is wound, the multiple straight sections 1111 are stacked along the thickness direction of the battery cell 100, and each straight section 1111 may be connected to a pole ear 113. A part of the pole ears 113 are stacked to form a positive pole ear 190, and another part of the pole ears 113 are stacked to form a negative pole ear 210. The bent sections 1113 are stacked to form two corners 230 on the left and right sides of the battery cell 100.

[0050] As another example, when the battery cell 100 is a laminated battery cell (eg Figure 1 and Figure 3 As shown in FIG, each electrode piece 110 may be connected to a electrode tab 113. When the first electrode piece and the second electrode piece are stacked, a portion of the electrode tabs 113 are stacked to form a positive electrode tab 190, and another portion of the electrode tabs 113 are stacked to form a negative electrode tab 210.

[0051] The pole piece 110 is provided with a plurality of first holes 117 , and the plurality of first holes 117 may be distributed at intervals.

[0052] The plurality of first holes 117 include a central hole 1171 . The central hole 1171 is located at a connection position between the tab 113 and the base 111 . The connection position 115 may refer to a junction position between the tab 113 and the base 111 .

[0053] A plurality of reference arcs 119 are defined that are concentric with the central hole 1171 . The plurality of reference arcs 119 are distributed outside the central hole 1171 , and their diameters gradually increase from the inside to the outside of the central hole 1171 .

[0054] It should be noted that the reference arc 119 may refer to an arc line. The reference arc 119 may be printed on the substrate 111 as a visible structural line. The reference arc 119 may also not be reflected on the substrate 111 and only serve as an auxiliary line when punching (the first hole 117).

[0055] Except for the central hole 1171, the remaining first holes 117 are distributed on multiple reference arcs 119 and are all provided on the substrate 111. In this way, multiple first holes 117 are provided on the substrate 111 in the area near the pole ear 113, which helps to optimize the distribution of current in the area near the pole ear 113, reduce the lithium ion deintercalation rate and total amount near the pole ear 113, and increase the contact area between the electrolyte and the pole piece 110, improve the wetting effect of the electrolyte in the area near the pole ear 113, thereby reducing the temperature rise of the pole ear 113, improving the lithium deposition in the area near the pole ear 113, and reducing the thermal runaway in the area near the pole ear 113. In addition, multiple first holes 117 are distributed on multiple reference arcs 119, which can optimize the distribution of the first holes 117 on the substrate 111, further optimize the current distribution, and help determine the punching positions of multiple first holes 117, thereby improving the punching efficiency.

[0056] The multiple first holes 117 being distributed on the multiple reference arcs 119 may refer to the centers of the multiple first holes 117 being distributed on the multiple reference arcs 119. In other embodiments, the multiple first holes 117 being distributed on the multiple reference arcs 119 may refer to other positions of the multiple first holes 117 being distributed on the reference arcs 119.

[0057] As an example, the number of first holes 117 can be 15, and the number of reference arcs 119 can be 4. Among the 15 first holes 117, one is a center hole 1171, which can be located at the junction of the tab 113 and the base 111. The remaining 14 first holes 117 can be distributed on the four reference arcs 119. Each reference arc 119 can be distributed with a first hole 117, and the number of first holes 117 on each reference arc 119 can be set as required.

[0058] In some embodiments, the center of the center hole 1171 may be located on the length centerline 1131 of the tab 113, thereby determining the drilling position of the center hole 1171 and the position of the subsequent reference arc 119 to determine the drilling positions of the remaining first holes 117. The length centerline 1131 of the tab 113 may be substantially parallel to the width direction Z of the pole piece 110.

[0059] As an example, a reference line 1151 is defined as a line connecting the junction of the tab 113 and the substrate 111 . The center hole 1171 may be located at the intersection of the connecting line and the length center line 1131 of the tab 113 .

[0060] The center hole 1171 can be set in a variety of ways. For example, the center of the center hole 1171 can coincide with the intersection of the connecting line and the length center line 1131 of the pole lug 113, or the center of the center hole 1171 can also not coincide with the intersection of the connecting line and the length center line 1131 of the pole lug 113, or the center hole 1171 is located on the base 111, and a quadrant point of the center hole 1171 coincides with the intersection of the connecting line and the length center line 1131 of the pole lug 113.

[0061] In some embodiments, the substrate 111 may include a current collector and an active material coating applied to the surface of the current collector. For example, both the upper surface and the lower surface of the current collector may be coated with the active material coating.

[0062] In some embodiments, the distribution density of the first holes 117 decreases from the direction close to the center hole 1171 to the direction away from the center hole 1171, that is, the closer to the tab 113, the greater the distribution density of the first holes 117, and the farther away from the tab 113, the smaller the distribution density of the first holes 117.

[0063] It can be understood that the current density in the area near the connection position 115 of the tab 113 and the substrate 111 is relatively high. Increasing the distribution density of the first holes 117 in the area near the tab 113 helps reduce the current concentration in the area near the tab 113, reduces the lithium ion deintercalation rate and total amount in the area near the tab 113, reduces the temperature rise in the area near the tab 113, and improves the lithium deposition in the area near the tab 113. In the area far from the connection position 115 of the tab 113 and the substrate 111, the current density is relatively low, and the temperature rise is also relatively low. Reducing the distribution density of the first holes 117 helps reduce the loss of the active material coating.

[0064] In some embodiments, the first hole 117 may be a blind hole. In this way, the first hole 117 may increase the contact area between the electrolyte and the electrode 110 , improve the infiltration effect of the electrolyte in the area near the electrode tab 113 , and reduce lithium plating.

[0065] As an example, the first hole 117 can be provided in the active material coating on the upper surface or lower surface of the current collector, or the first hole 117 can also penetrate the active material coating on the upper surface or lower surface of the current collector, or the first hole 117 can also penetrate the active material coating on the upper surface or lower surface of the current collector and extend to the current collector.

[0066] In some embodiments, the first hole 117 may be a through hole. Thus, the first hole 117 may provide a flow channel for the electrolyte, thereby helping to remove heat near the tab 113 , reduce the temperature rise of the tab 113 , and reduce lithium deposition.

[0067] As an example, the first holes 117 may penetrate the current collector and the active material coatings on the upper and lower surfaces of the current collector.

[0068] In some embodiments, the shape of the first hole 117 can be set as required. For example, the first hole 117 can be a frustum hole, a cylindrical hole, an elliptical cylinder hole, a conical hole, a spherical cap hole (semicircular groove) or a hole of other shapes.

[0069] In some embodiments, two adjacent reference arcs 119 are named a first arc and a second arc, and the first arc is located inside the second arc, that is, the radius of the first arc is smaller than the radius of the second arc.

[0070] The hole spacing between two adjacent first holes 117 located on the first arc is equal to the difference in radius between the first arc and the second arc, which can further optimize the distribution of the first holes 117 on the substrate 111 and help better determine the hole spacing of the first holes 117 and the radius of the reference arc 119.

[0071] As an example, if the radius of the first arc is 5 mm and the hole spacing of the first holes 117 distributed on the first arc is 1 mm, then the radius of the second arc can be determined to be 6 mm.

[0072] As another example, if the radius of the first arc is 5 mm and the radius of the second arc is 7 mm, it can be determined that the hole spacing of the first holes 117 distributed on the first arc is 2 mm.

[0073] Please continue reading Figures 3 and 4 In some embodiments, the radius of the reference arc 119 is defined as r, the diameter of the first hole 117 is defined as d, the length of the tab 113 is defined as w, the width of the substrate 111 is defined as a, and the hole spacing between adjacent first holes 117 located on the same reference arc 119 is defined as L.

[0074] When the electrode 110 is applied to a wound battery cell (e.g. Figure 2As shown), the minimum distance between the length center line 1131 of the tab 113 and the side of the straight section 1111 along the length direction Y is c, and the length of the straight section 1111 is b.

[0075] When the pole piece 110 is applied to a laminated battery cell ( Figure 3 As shown), the minimum distance between the length center line 1131 of the tab 113 and the side of the base 111 along the length direction Y is c, and the length of the base 111 is b.

[0076] Among them, when , the number of the first holes 117 located on the reference arc 119 is That is, when r is greater than 0.5d and less than or equal to When the minimum of the two values ​​of c and c, the number of the first holes 117 on the reference arc 119 is indivual.

[0077] when , the number of the first holes 117 located on the reference arc 119 is That is, when the value of r is When the values ​​of and c are between the two, the number of the first holes 117 on the reference arc 119 is indivual.

[0078] when , the number of the first holes 117 located on the reference arc 119 is That is, when r is greater than , c is the maximum value between the two values ​​and is less than or equal to a, the number of the first holes 117 on the reference arc 119 is If the electrode 110 is a negative electrode 170 , then 0.5 mm ≤ L ≤ 1 mm, and 0.5 ≤ k ≤ 2; if the electrode 110 is a positive electrode 150 , then 0.5 mm ≤ L ≤ 2 mm, and 0.6 ≤ k ≤ 3.

[0079] In this way, this embodiment helps to more accurately control the distribution of the first holes 117 by calculating the number of first holes 117 on the reference arc 119 of different radii, which helps to ensure the capacity of the battery while improving lithium deposition in the area near the tab 113.

[0080] As an example, when the negative electrode sheet 170 is provided with a plurality of first holes 117 , L may be 0.5 mm, 0.7 mm, 0.9 mm, 1 mm or other values ​​in the interval [0.5 mm, 1 mm], and k may be 0.5, 0.7, 1.5, 2 or other values ​​in the interval [0.5, 2].

[0081] As another example, when the positive electrode sheet 150 is provided with the first hole 117, L can be 0.5 mm, 0.8 mm, 1.4 mm, 2 mm or other values ​​in the interval [0.5 mm, 2 mm], and k can be 0.6, 0.9, 2, 3 or other values ​​in the interval [0.6, 3].

[0082] In addition, when r=0.5d, that is, the radii of the reference arc 119 and the first hole 117 are equal, only one first hole 117 can be set on the reference arc 119. The first hole 117 can serve as the center hole 1171, and the first hole 117 can also be concentric with the reference arc 119.

[0083] In some embodiments, the first holes 117 on the reference arc 119 may be distributed at equal intervals, which helps to make the current distribution more uniform and also helps to simplify the difficulty of drilling.

[0084] The spacing between adjacent first holes 117 may refer to the straight-line distance between the circumference lines of adjacent first holes 117 .

[0085] In some embodiments, when 0.5d<r≤0.5w, the hole spacing between adjacent first holes 117 located on the reference arc 119 is L, wherein, if the electrode 110 is a negative electrode 170, then 0.5mm≤L≤1mm; if the electrode 110 is a positive electrode 150, then 0.5mm≤L≤2mm, 0.6≤k≤3, so that L can have a certain range of values, which helps to ensure that the first holes 117 in the area near the electrode tab 113 can have a sufficiently large distribution density, helps to optimize the current distribution in the area near the electrode tab 113, and improves lithium deposition.

[0086] Specifically, when the radius of the reference arc 119 is within the interval (0.5d, 0.5w]), the hole spacing between adjacent first holes 117 located on the reference arc 119 is L.

[0087] When 0.5w<r<0.5a, the hole spacing between adjacent first holes 117 located on the reference arc 119 is H, where If the electrode 110 is the negative electrode 170 , then 0.5 mm ≤ L ≤ 1 mm, and 0.5 ≤ k ≤ 2; if the electrode 110 is the positive electrode 150 , then 0.5 mm ≤ L ≤ 2 mm, and 0.6 ≤ k ≤ 3.

[0088] Specifically, when the radius of the reference arc 119 is within the interval (0.5w, 0.5a), the hole spacing between adjacent first holes 117 located on the reference arc 119 is H.

[0089] In this way, the hole spacing of the first holes 117 on the electrode 110 can be calculated using the above formula, so that the distribution of the first holes 117 can be more accurately controlled, which helps to ensure the capacity of the battery while improving lithium deposition in the area near the electrode tab 113.

[0090] As an example, when the negative electrode sheet 170 is provided with a plurality of first holes 117 , L may be 0.5 mm, 0.6 mm, 0.8 mm, 1 mm or other values ​​in the interval [0.5 mm, 1 mm], and k may be 0.5, 0.6, 1.2, 2 or other values ​​in the interval [0.5, 2].

[0091] As another example, when the positive electrode sheet 150 is provided with the first hole 117, L can be 0.5 mm, 0.6 mm, 1 mm, 2 mm or other values ​​in the interval [0.5 mm, 2 mm], and k can be 0.6, 0.8, 2.2, 3 or other values ​​in the interval [0.6, 3].

[0092] As another example, when both the positive electrode sheet 150 and the negative electrode sheet 170 are provided with the first hole 117 , the value of L on the positive electrode sheet 150 may be greater than or equal to the value of L on the negative electrode sheet 170 .

[0093] In addition, when both the positive electrode sheet 150 and the negative electrode sheet 170 are punched, the value of L can also be controlled so that the hole spacing between adjacent first holes 117 on the positive electrode sheet 150 can be greater than or equal to the hole spacing between adjacent first holes 117 on the negative electrode sheet 170, which helps to better optimize the current distribution, reduce temperature rise, and improve lithium deposition.

[0094] In some embodiments, the depth of the first hole 117 can be greater than or equal to 40% of the thickness of the substrate 111, thereby ensuring that the first hole 117 has sufficient depth, which helps the first hole 117 to optimize current distribution, reduce temperature rise, and improve lithium deposition in the area near the tab 113.

[0095] As an example, when the negative electrode sheet 170 is provided with the first hole 117 , the depth of the first hole 117 may be 40%, 55%, 70%, 80% of the thickness of the substrate 111 or other values.

[0096] As another example, when the positive electrode sheet 150 is provided with the first hole 117 , the depth of the first hole 117 may be 40%, 45%, 70%, or 80% of the thickness of the substrate 111 , or the first hole 117 may penetrate the substrate 111 .

[0097] Furthermore, when both the positive electrode sheet 150 and the negative electrode sheet 170 are provided with a plurality of first holes 117, the depth of the first holes 117 on the positive electrode sheet 150 may be greater than or equal to the depth of the first holes 117 on the negative electrode sheet 170. This allows for better control of the capacity loss of the negative electrode sheet 170 and the positive electrode sheet 150, helping to better ensure that the capacity loss of the negative electrode sheet 170 / the capacity loss of the positive electrode sheet 150 is less than the initial N / P (Negative / Positive) ratio of the electrode sheet, thereby ensuring the electrical performance of the battery cell 100. Furthermore, the initial N / P ratio of the electrode sheet may refer to the ratio of the capacity loss of the negative electrode sheet 170 without the first holes 117 to the capacity loss of the positive electrode sheet 150 without the first holes 117.

[0098] In some embodiments, if the electrode 110 is a negative electrode 170, the diameter of the first hole 117 can be greater than or equal to 50 μm and less than or equal to 500 μm; if the electrode 110 is a positive electrode 150, the diameter of the first hole 117 can be greater than or equal to 500 μm and less than or equal to 2000 μm, so that the diameter of the first hole 117 can be controlled within an appropriate range, which helps to avoid drilling difficulties due to a hole diameter that is too small, and also helps to avoid local lithium deposition due to a hole diameter that is too large.

[0099] As an example, when the negative electrode sheet 170 is provided with the first hole 117 , the diameter of the first hole 117 may be 50 μm, 100 μm, 180 μm, 210 μm, 500 μm, or other values ​​in the range of [50 μm, 500 μm].

[0100] As another example, when the positive electrode sheet 150 is provided with the first hole 117 , the diameter of the first hole 117 may be 50 μm, 100 μm, 180 μm, 210 μm, 300 μm, or other values ​​in the range of [500 μm, 2000 μm].

[0101] In addition, when both the positive electrode sheet 150 and the negative electrode sheet 170 are provided with multiple first holes 117, the diameter of the first hole 117 on the positive electrode sheet 150 can be greater than or equal to the diameter of the first hole 117 on the negative electrode sheet 170, so that the capacity loss of the negative electrode sheet 170 and the positive electrode sheet 150 can be better controlled to ensure the electrical performance of the battery cell 100, and the wetting effect of the electrolyte in the positive electrode sheet 150 can also be improved, which helps to improve the electrical performance of the battery cell 100.

[0102] In some embodiments, V is defined as the volume of a single first hole 117, N is the number of first holes 117 per unit area, M is the overall density of the active material coating when the first hole 117 is not provided on the substrate 111, W is the surface density of the substrate 111, X is the percentage of active material in the active material coating, and A is the loss percentage of the active material coating.

[0103] Wherein, A=V×N×M / (W×X)×100%, so that the size and number of the first holes 117 and the loss percentage of the active material coating can be better controlled by the formula, which helps to avoid the situation where the battery capacity decreases due to a large loss of the active material coating.

[0104] It can be understood that when the battery cell 100 is a wound battery cell, since the first hole 117 is only provided on the straight segment 1111, A can be the loss percentage of the active material coating on a straight segment 1111 on the substrate 111, and correspondingly, N is the number of first holes 117 per unit area on a straight segment 1111, M is the overall density of the active material coating when the first hole 117 is not provided on a straight segment 1111, W is the surface density of a straight segment 1111, and X is the percentage of active material in the active material coating on a straight segment 1111.

[0105] In some embodiments, if the electrode 110 is a negative electrode 170, 0.5%≤A≤4%; if the electrode 110 is a positive electrode 150, 1%≤A≤10%. In this way, the loss percentage of the active material coating is controlled within an appropriate range, which helps to ensure the capacity of the battery while improving lithium plating, and avoid the situation where the loss of the active material coating is large due to an excessive number or excessive size of the first holes 117, thereby leading to a decrease in battery capacity.

[0106] As an example, when the negative electrode sheet 170 is provided with the first hole 117 , the loss percentage A of the active material coating of the negative electrode sheet 170 may be 0.5%, 1.2%, 2.5%, 4%, or other values ​​in the range of [0.5%, 4%].

[0107] As another example, when the positive electrode sheet 150 is provided with the first hole 117 , the loss percentage A of the active material coating of the negative electrode sheet 170 may be 1%, 4.2%, 6%, 10%, or other values ​​in the range of [1%, 10%].

[0108] In addition, when both the positive electrode sheet 150 and the negative electrode sheet 170 are provided with a plurality of first holes 117 , the capacity loss of the negative electrode sheet 170 / the capacity loss of the positive electrode sheet 150 is less than the initial N / P (Negative / Positive) ratio of the electrode sheet 110 , thereby ensuring the electrical performance of the battery cell 100 .

[0109] See also Figure 2 、 Figure 5 and Figure 6 In some embodiments, the bent section 1113 may be provided with a plurality of second holes 1115, thereby improving the wetting effect of the electrode 110 of the battery cell 100 at the corner 230, increasing the liquid retention performance of the battery cell 100 in the corner 230 area, promoting the power performance of lithium ions, and helping lithium ions to embed or detach from the electrode 110 more quickly, which can improve the lithium deposition situation at the corner 230.

[0110] In some embodiments, the second hole 1115 can be a blind hole or a through hole. For details, please refer to the first hole 117 and will not be repeated here.

[0111] The shape of the second hole 1115 can also be designed according to needs. For details, please refer to the first hole 117 and will not be repeated here.

[0112] In some embodiments, at least one of the positive electrode sheet 150 and the negative electrode sheet 170 is provided with a second hole 1115 in the bent section 1113 .

[0113] The second hole 1115 on the positive electrode sheet 150 can be a blind hole or a through hole. When the second hole 1115 is a through hole, the second hole 1115 can penetrate the substrate 111 of the positive electrode sheet 150 to improve the infiltration effect of the electrolyte.

[0114] The second hole 1115 on the negative electrode sheet 170 may be a blind hole, which helps to avoid lithium deposition caused by the second hole 1115 penetrating the negative electrode sheet 170 .

[0115] In some embodiments, if the electrode 110 is a negative electrode 170, the diameter of the second hole 1115 is greater than or equal to 50 μm and less than or equal to 300 μm; if the electrode 110 is a positive electrode 150, the diameter of the second hole 1115 is greater than or equal to 500 μm and less than or equal to 2000 μm. In this way, controlling the aperture of the second hole 1115 within an appropriate range helps to reduce the loss of active material coating on the basis of improving lithium plating, thereby ensuring the capacity of the battery. In addition, it also helps to avoid difficulties in drilling due to too small an aperture.

[0116] As an example, when the negative electrode sheet 170 is provided with the second hole 1115 , the diameter of the second hole 1115 may be 50 μm, 100 μm, 180 μm, 210 μm, 300 μm, or other values ​​in the range of [50 μm, 300 μm].

[0117] As another example, when the positive electrode sheet 150 is provided with the second hole 1115 , the diameter of the second hole 1115 may be 50 μm, 100 μm, 180 μm, 210 μm, 300 μm, or other values ​​in the range of [500 μm, 2000 μm].

[0118] In addition, when the positive electrode sheet 150 and the negative electrode sheet 170 are both provided with a second hole 1115 in the bending section 1113, the diameter of the second hole 1115 on the positive electrode sheet 150 can be greater than or equal to the diameter of the second hole 1115 on the negative electrode sheet 170, so that the capacity loss of the negative electrode sheet 170 and the positive electrode sheet 150 can be better controlled to ensure the electrical performance of the battery cell 100, and the wetting effect of the electrolyte in the positive electrode sheet 150 can also be improved, which helps to improve the electrical performance of the battery cell 100.

[0119] In some embodiments, if the electrode 110 is a negative electrode 170, the depth of the second hole 1115 is greater than or equal to 40% of the thickness of the substrate 111 and less than or equal to 80% of the thickness of the substrate 111; if the electrode 110 is a positive electrode 150, the depth of the second hole 1115 is greater than or equal to 30% of the thickness of the substrate 111. In this way, controlling the depth of the second hole 1115 within an appropriate range helps to reduce the loss of the active material coating on the basis of improving lithium plating and ensure the capacity of the battery.

[0120] As an example, when the negative electrode sheet 170 is provided with the second hole 1115 , the depth of the second hole 1115 may be 40%, 55%, 70%, 80% of the thickness of the substrate 111 or other values.

[0121] As another example, when the negative electrode sheet 170 is provided with the second hole 1115 , the depth of the second hole 1115 may be 30%, 45%, 70%, or 80% of the thickness of the substrate 111 , or the second hole 1115 may penetrate the substrate 111 .

[0122] In addition, when the positive electrode sheet 150 and the negative electrode sheet 170 are both provided with a second hole 1115 in the bending section 1113, the hole depth of the second hole 1115 on the positive electrode sheet 150 can be greater than or equal to the hole depth of the second hole 1115 on the negative electrode sheet 170, which helps to distribute the electrolyte more evenly in the positive electrode sheet 150, improves the infiltration effect of the electrolyte in the positive electrode sheet 150, and improves the electrical performance of the battery cell 100.

[0123] In some embodiments, if the electrode 110 is a negative electrode 170, the hole spacing between two adjacent second holes 1115 is greater than or equal to 0.4 mm and less than or equal to 2 mm; if the electrode 110 is a positive electrode 150, the hole spacing between two adjacent second holes 1115 is greater than or equal to 1 mm and less than or equal to 5 mm. In this way, controlling the hole spacing between adjacent second holes 1115 within an appropriate range helps to reduce the loss of active material coating on the basis of improving lithium plating, thereby ensuring the capacity of the battery. In addition, it also helps to avoid processing difficulties caused by too small hole spacing.

[0124] As an example, when the negative electrode sheet 170 is provided with the second holes 1115 , the hole spacing between adjacent second holes 1115 may be 0.4 mm, 0.9 mm, 1.5 mm, 2 mm, or other values ​​in the range of [0.4 mm, 2 mm].

[0125] As another example, when the positive electrode sheet 150 is provided with second holes 1115 , the hole spacing between adjacent second holes 1115 may be 1 mm, 2 mm, 3.5 mm, 5 mm, or other values ​​in the interval [1 mm, 5 mm].

[0126] In addition, when both the positive electrode sheet 150 and the negative electrode sheet 170 are provided with a second hole 1115 in the bending section 1113, the hole spacing between adjacent second holes 1115 on the positive electrode sheet 150 can be greater than or equal to the hole spacing between adjacent second holes 1115 on the negative electrode sheet 170, thereby better controlling the capacity loss of the negative electrode sheet 170 and the positive electrode sheet 150 to ensure the electrical performance of the battery cell 100, and also improving the wetting effect of the electrolyte in the positive electrode sheet 150, which helps to improve the electrical performance of the battery cell 100.

[0127] See also Figures 4 and 5 In some embodiments, when the battery cell 100 is a wound battery cell, the electrode piece 110 may be provided with a first hole 117 in the straight section 1111 and a second hole 1115 in the bent section 1113, or the electrode piece 110 may be provided with the first hole 117 only in the straight section 1111, or the electrode piece 110 may be provided with the second hole 1115 only in the bent section 1113.

[0128] See also Figure 3 When the battery cell 100 is a laminated battery cell, only the first hole 117 may be provided on the base 111 of the electrode piece 110 .

[0129] In the pole piece 110, the battery cell 100 and the battery provided in the embodiment of the present application, the pole piece 110 is provided with a plurality of first holes 117, and the plurality of first holes 117 include a central hole 1171 located at the connection position between the pole ear 13 and the base 111. The remaining first holes 117 except the central hole 1171 are distributed on a plurality of reference arcs 119 outside the central hole 1171 and are all provided on the base 111. In this way, the plurality of first holes 117 are provided in the vicinity of the pole ear 113, which helps to optimize the distribution of the current in the vicinity of the pole ear 113 and reduce the lithium ion near the pole ear 113. The rate and total amount of lithium insertion and extraction can also be increased, and the contact area between the electrolyte and the electrode 110 can be increased, and the infiltration effect of the electrolyte in the area near the electrode 113 can be improved, thereby reducing the temperature rise of the electrode 113, improving the lithium deposition in the area near the electrode 113, and reducing the thermal runaway in the area near the electrode 113. In addition, the multiple first holes 117 are distributed on the multiple reference arcs 119, which can optimize the distribution of the first holes 117 on the substrate 111, further optimize the distribution of the current, and help determine the punching positions of the multiple first holes 117, thereby improving the punching efficiency.

[0130] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments. Various modifications can be made within the scope of knowledge possessed by a person skilled in the art without departing from the spirit of the present invention. In addition, the embodiments of the present invention and the features of the embodiments can be combined with each other unless there is a conflict.

Claims

1. A pole piece, characterized in that: The pole piece is provided with a plurality of first holes, and the pole piece comprises: substrate; and a tab connected to the substrate; Among them, the multiple first holes include a center hole, which is arranged at the connection position of the tab and the base; multiple reference arcs are defined that are concentric with the center hole, and the multiple reference arcs are distributed on the outside of the center hole, and the diameters gradually increase from the inside to the outside of the center hole; the remaining first holes except the center hole are distributed on the multiple reference arcs and are all arranged on the base.

2. The pole piece according to claim 1, characterized in that: The plurality of reference arcs include a first arc and a second arc that are adjacent to each other, and the first arc is located inside the second arc; The hole spacing between two adjacent first holes on the first arc is equal to the difference between the radii of the first arc and the second arc.

3. The pole piece according to claim 1, characterized in that: The pole piece has a length direction and a width direction, and the pole tab is connected to one side of the substrate along the width direction; the radius of the reference arc is defined as r, the diameter of the first hole is defined as d, the length of the pole tab is defined as w, the width of the substrate is defined as a, and the hole spacing between adjacent first holes located on the same reference arc is defined as L; The pole piece is applied to a wound battery cell, and the base includes straight sections and bent sections alternately distributed along the length direction; after the pole piece is wound, a plurality of the straight sections are stacked, and the pole tab is connected to the straight section, and the minimum distance between the length centerline of the pole tab and the side of the straight section along the width direction is c, and the length of the straight section is b; or, the pole piece is applied to a laminated battery cell, and the minimum distance between the length centerline of the pole tab and the side of the base along the width direction is c, and the length of the base is b; Among them, when , the number of the first holes located on the reference arc is ;when , the number of the first holes located on the reference arc is ;when , the number of the first holes located on the reference arc is ; and / or, when 0.5d<r≤0.5w, the hole spacing between adjacent first holes located on the reference arc is L; when 0.5w<r<0.5a, the hole spacing between adjacent first holes located on the reference arc is H, ; If the electrode is a negative electrode, 0.5 mm ≤ L ≤ 1 mm, and 0.5 ≤ k ≤ 2; if the electrode is a positive electrode, 0.5 mm ≤ L ≤ 2 mm, and 0.6 ≤ k ≤ 3.

4. The pole piece according to claim 1, characterized in that: The pole piece has a length direction and a width direction, the pole tab is connected to one side of the base along the width direction; the center of the center hole is located on the length center line of the pole tab along the length direction.

5. The pole piece according to claim 1, characterized in that: The distribution density of the first holes decreases from close to the central hole to away from the central hole.

6. The pole piece according to claim 1, characterized in that: The depth of the first hole is greater than or equal to 40% of the thickness of the substrate; And / or, if the electrode sheet is a negative electrode sheet, the diameter of the first hole is greater than or equal to 50 μm and less than or equal to 500 μm; If the electrode is a positive electrode, the diameter of the first hole is greater than or equal to 500 μm and less than or equal to 2000 μm; And / or, the substrate includes a current collector and an active material coating coated on the surface of the current collector, the loss percentage of the active material coating is A, if the electrode is a negative electrode, 0.5%≤A≤4%; if the electrode is a positive electrode, 1%≤A≤10%.

7. The pole piece according to claim 1, characterized in that: The base includes straight sections and bent sections that are alternately distributed along the width direction; after the pole piece is wound, a plurality of the straight sections are stacked, and the bent sections are provided with a plurality of second holes.

8. The pole piece according to claim 7, characterized in that: If the electrode is a negative electrode, the diameter of the second hole is greater than or equal to 50 μm and less than or equal to 300 μm; if the electrode is a positive electrode, the diameter of the second hole is greater than or equal to 500 μm and less than or equal to 2000 μm; And / or, if the electrode sheet is a negative electrode sheet, the hole depth of the second hole is greater than or equal to 40% of the thickness of the substrate and less than or equal to 80% of the thickness of the substrate; if the electrode sheet is a positive electrode sheet, the hole depth of the second hole is greater than or equal to 30% of the thickness of the substrate; And / or, if the electrode sheet is a negative electrode sheet, the hole spacing between two adjacent second holes is greater than or equal to 0.4 mm and less than or equal to 2 mm; if the electrode sheet is a positive electrode sheet, the hole spacing between two adjacent second holes is greater than or equal to 1 mm and less than or equal to 5 mm.

9. A battery cell, characterized in that: It comprises a first pole piece and a second pole piece, wherein at least one of the first pole piece and the second pole piece is the pole piece according to any one of claims 1 to 8.

10. A battery, characterized in that: Comprising the battery cell according to claim 9.

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