Electrode plate and battery

Abstract

The utility model relates to the field of lithium ion batteries, in particular to an electrode plate and a battery, which comprise a current collector and an active material layer arranged on at least one side of the current collector, the surface of the electrode plate comprises a perforation area and a routing area; the wire bonding area comprises at least one wire slot; the perforation area comprises at least one through hole; wherein the perforation area comprises a first perforation area and a second perforation area; in the first direction, the first perforation area and the second perforation area are arranged on the two sides of the routing area; and the through hole penetrates through the current collector and the active material layer. The circulating capacity retention ratio of the battery is remarkably improved by arranging the wire slot on the surface of the electrode plate, and meanwhile, the circulating expansion of the battery is reduced by matching with the through holes formed in the two sides of the wire slot, so that the permeation speed of electrolyte from the edge of the electrode plate to the center can be remarkably improved, and the problem of lithium precipitation of the battery is solved; and the wire duct is more easily filled with the electrolyte, so that the lithium precipitation is further reduced.

Description

Technical Field

[0001] The utility model relates to the field of lithium - ion batteries, and particularly to an electrode plate and a battery. Background Art

[0002] In recent years, the new energy industry has risen rapidly, and among them, an important energy storage device - lithium - ion batteries has received extensive attention in the fields of consumer digital products and electric vehicles. With the increasing demand for energy storage, lithium - ion batteries themselves are also developing towards high - energy - density directions such as thick electrodes and silicon anodes.

[0003] The wetting problem is an important problem affecting the performance of lithium - ion batteries, directly affecting the advantages and disadvantages of various performances of the battery such as rate performance, storage performance, and cycle performance. With the increase in energy density, the higher the specific capacity of the battery, the higher the electrode compaction density, and the greater the electrode thickness, the more difficult it is for the battery to be wetted, which further leads to problems such as low cycle capacity retention rate, high cycle expansion, and serious lithium deposition phenomena at the edge and center of the battery.

[0004] Therefore, for the problems of low cycle capacity retention rate, high cycle expansion, and serious lithium deposition phenomena at the edge and center of the battery caused by poor battery wetting in the prior art, it is urgent for those skilled in the art to solve. Summary of the Utility Model

[0005] The purpose of the utility model is to provide an electrode plate and a battery to solve the problems of low cycle capacity retention rate, high cycle expansion, and serious lithium deposition phenomena at the edge and center of the battery caused by poor battery wetting in the prior art.

[0006] To solve the above - mentioned technical problems, the utility model provides an electrode plate, which includes a current collector and an active material layer disposed on at least one side of the current collector; the surface of the electrode plate includes a perforated area and a wire - bonding area;

[0007] The wire - bonding area includes at least one wire groove; the perforated area includes at least one through - hole;

[0008] Among them, the perforated area includes a first perforated area and a second perforated area; along a first direction, the first perforated area and the second perforated area are disposed on both sides of the wire - bonding area;

[0009] The through - hole penetrates through the current collector and the active material layer.

[0010] Optionally, in the electrode plate, the perforated area further includes a third perforated area and a fourth perforated area; along a second direction, the third perforated area and the fourth perforated area are disposed on both sides of the wire - bonding area, and the second direction is perpendicular to the first direction.

[0011] Optionally, in the electrode tab, the wire bonding area further includes auxiliary through holes, the wire bonding area includes a plurality of wire grooves, and the auxiliary through holes are disposed in the wire grooves or between two adjacent wire grooves;

[0012] The auxiliary through holes penetrate through the current collector and the active material layer.

[0013] Optionally, in the electrode tab, along the thickness direction of the electrode tab, the depth of the wire groove is less than the thickness of the active material layer.

[0014] Optionally, in the electrode tab, the active material layer includes a first active material layer and a second active material layer, the through hole is a frustum-shaped through hole, and the frustum-shaped through hole includes a first hole and a second hole;

[0015] Along the direction from the first active material layer towards the second active material layer, the aperture of the first hole gradually decreases, and the aperture of the second hole gradually increases;

[0016] The first hole and the second hole are arranged adjacent to each other in the perforation area.

[0017] Optionally, in the electrode tab, a plurality of the first holes and a plurality of the second holes are alternately arranged in the perforation area.

[0018] Optionally, in the electrode tab, the compaction density of the punching action area within the first radius around the through hole is less than the compaction density of the non-punching action area;

[0019] The compaction density of the punching action area ranges from 0.65 g / cc to 1.9 g / cc, including the end point values;

[0020] and / or the compaction density of the non-punching action area ranges from 0.8 g / cc to 2.0 g / cc, including the end point values;

[0021] The range of the first radius is from 15 microns to 70 microns, including the end point values.

[0022] Optionally, in the electrode tab, the range of the hole pitch of the through hole is from 200 microns to 500 microns, including the end point values;

[0023] and / or the range of the aperture of the through hole is from 40 microns to 100 microns, including the end point values;

[0024] and / or the ratio of the hole pitch to the aperture ranges from 4 to 10, including the end point values;

[0025] and / or the range of the width of the perforation area is from 0.1 mm to 10 mm, including the end point values.

[0026] A battery, wherein the first electrode tab and / or the second electrode tab of the battery is the electrode tab as described in any one of the above.

[0027] Optionally, in the battery described above, the battery is a wound battery;

[0028] The perforated area is arranged at the arc-shaped bending part of the wound battery.

[0029] The electrode tab provided by the present utility model includes a current collector and an active material layer arranged on at least one side of the current collector; the surface of the electrode tab includes a perforated area and a wire bonding area; the wire bonding area includes at least one wire groove; the perforated area includes at least one through hole; wherein, the perforated area includes a first perforated area and a second perforated area; along a first direction, the first perforated area and the second perforated area are arranged on both sides of the wire bonding area; the through hole penetrates through the current collector and the active material layer. By arranging wire grooves on the surface of the electrode tab, the present utility model significantly improves the cycle capacity retention rate of the battery. At the same time, in cooperation with the through holes arranged on both sides of the wire grooves, the cycle expansion of the battery is reduced. At the same time, arranging the through holes can significantly improve the penetration speed of the electrolyte from the edge of the electrode tab to the center, enabling lithium ions to be transmitted faster and greatly improving the problem of lithium deposition in the battery. The wire grooves have a capillary action on the electrolyte, making it easier for the electrolyte to fill the wire grooves, further reducing lithium deposition caused by insufficient electrolyte. The present utility model also provides a battery having the above beneficial effects. Description of the Drawings

[0030] In order to more clearly illustrate the technical solutions of the embodiments of the present utility model or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present utility model. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0031] Figure 1 It is a schematic structural diagram of a specific embodiment of the electrode tab provided by the present utility model;

[0032] Figure 2 、 Figure 3 、 Figure 4 It is a top view of the structure of a specific embodiment of the electrode tab provided by the utility model;

[0033] Figure 5 、 Figure 6 、 Figure 7 It is a top view of the structure of another specific embodiment of the electrode tab provided by the utility model;

[0034] Figure 8 、Figure 9 A top view of the structure of still another specific embodiment of the electrode tab for the utility model;

[0035] Figure 10 A schematic structural view of still another specific embodiment of the electrode tab for the utility model;

[0036] Figure 11 、 Figure 12 A microscopic scanning image of the through - hole of a specific embodiment of the electrode tab for the utility model.

[0037] In the figure, it includes 101 - current collector, 102 - active material layer, 102A - first active material layer, 102B - second active material layer, 201 - wire groove, 202 - through - hole, 202A - first hole, 202B - second hole, 203 - auxiliary through - hole, 210 - wire bonding area, 220A - first perforation area, 220B - second perforation area, 220C - third perforation area, 220D - fourth perforation area. Specific Embodiment

[0038] In order to enable those skilled in the art to better understand the solution of the present utility model, the present utility model will be further described in detail below with reference to the drawings and specific embodiments. Obviously, the described embodiments are only a part of the embodiments of the present utility model, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present utility model without making creative efforts belong to the scope of protection of the present utility model.

[0039] The core of the present utility model is to provide an electrode tab, and a schematic structural view of a specific embodiment thereof is as Figure 1 shown, which is called Specific Embodiment 1, and includes a current collector 101 and an active material layer 102 provided on at least one side of the current collector 101; the surface of the electrode tab includes a perforation area and a wire bonding area 210;

[0040] The wire bonding area 210 includes at least one wire groove 201; the perforation area includes at least one through - hole 202;

[0041] Among them, the perforation area includes a first perforation area 220A and a second perforation area 220B; along a first direction, the first perforation area 220A and the second perforation area 220B are arranged on both sides of the wire bonding area 210;

[0042] The through - hole 202 penetrates through the current collector 101 and the active material layer 102.

[0043] The electrode plate in the present utility model has a laminated structure, including a current collector 101 and an active material layer 102 provided on at least one side of the current collector 101, and the perforation area and the wire bonding area 210 are different position areas within the electrode plate. Figure 1 It is a cross-sectional view of the electrode plate.

[0044] The first direction is the extending direction of a pair of opposite sides of the electrode plate. The first perforation area 220A and the second perforation area 220B are arranged along the first direction, and the first perforation area 220A, the wire bonding area 210, and the second perforation area 220B can be arranged in a "Sichuan" character shape.

[0045] As a specific implementation manner, the perforation area is provided on two side edges in the width direction of the electrode plate.

[0046] In other words, in this specific implementation manner, the perforation area is a strip-shaped area arranged along two long sides of the electrode plate. The corresponding first direction is the extending direction of the short side of the electrode plate. For specific reference, please refer to Figure 2 、 Figure 3 and Figure 4 . This setting method of the perforation area can greatly reduce the distance that the electrolyte needs to cross to cover the entire electrode plate, thereby achieving a better battery wetting effect. Of course, the arrangement direction of the wire grooves 201 in the wire bonding area 210 can be set arbitrarily. The extending directions of multiple wire grooves 201 can be the same or different. For example, the wire grooves 201 in Figure 2 can be arranged in parallel along the long axis direction of the electrode plate, Figure 3 the wire grooves 201 in Figure 4 can be arranged in parallel along the short axis direction of the electrode plate, and the wire grooves 201 in Figure 2 are arranged in a cross-perpendicular manner along two edge directions of the electrode plate. For the convenience of display, only the first direction, the first perforation area 220A, the second perforation area 220B, and the wire bonding area 210 are marked in Figure 2 . They are not marked in the other figures. Of course, in actual production, the first direction can also be other directions that are not the extending direction of the short side. The present utility model does not make any limitations in this regard.

[0047] In addition, in a battery, the electrolyte at the edge is relatively more than that in the middle area. There are problems such as poor wetting in the middle area and lithium deposition at the edge. The perforation area is provided at the edge of the electrode plate. The through holes penetrate the current collector and the active material layer, and lithium ions are transmitted faster, and the electrolyte penetrates faster, which can significantly improve the problem of lithium deposition at the edge.

[0048] Please refer to Figure 3In the markings in [reference], assume the width of the electrode tab is W, and at least one through-hole 202 is provided in the perforation area. The width of the perforation area is preferably 0 < W1 ≤ 10 mm, where W1 is the distance from the hole farthest from the edge of the electrode tab to the edge of the electrode tab. Inside the perforation area is the wire bonding area 210, and at least one wire groove 201 is provided in the wire bonding area 210. The width W2 of the wire bonding area 210 = W - 2 * W1.

[0049] Furthermore, the perforation area further includes a third perforation area 220C and a fourth perforation area 220D; along the second direction, the third perforation area 220C and the fourth perforation area 220D are arranged on both sides of the wire bonding area 210, and the second direction is perpendicular to the first direction.

[0050] In other words, in this preferred embodiment, the first perforation area 220A, the second perforation area 220B, the third perforation area 220C, and the fourth perforation area 220D form a strip-shaped area surrounding the wire bonding area 210.

[0051] Please refer to Figure 5 、 Figure 6 and Figure 7 , in this preferred embodiment, after adding the third perforation area 220C and the fourth perforation area 220D, the perforation area covers all the edges of the electrode tab, facilitating the rich electrolyte at the edge of the electrode tab to spread from all directions towards the center of the electrode tab through the through-hole 202, further improving the battery wetting effect. Figure 5 、 Figure 6 and Figure 7 also show wire grooves 201 in different arrangements. For the convenience of display, only the first direction, the second direction, the first perforation area 220A, the second perforation area 220B, the third perforation area 220C, the fourth perforation area 220D, and the wire bonding area 210 are marked in Figure 5 , and the rest of the figures are not marked.

[0052] As a preferred embodiment, the wire bonding area 210 further includes auxiliary through-holes 203. The wire bonding area 210 includes a plurality of wire grooves 201, and the auxiliary through-holes 203 are provided inside the wire grooves 201 or between two adjacent wire grooves 201;

[0053] The auxiliary through-holes 203 penetrate through the current collector 101 and the active material layer 102.

[0054] Reference can be made to Figure 8 and Figure 9 , the auxiliary through-holes 203 can be provided inside the wire grooves 201 (as shown in Figure 8 ), or can be provided between adjacent wire grooves 201 (as shown inFigure 9 ), by further providing the auxiliary through holes 203 in the wire bonding area 210, the porosity of the electrode plate can be further increased, and the battery infiltration rate can be further improved.

[0055] In addition, along the thickness direction of the electrode plate, the depth of the wire groove 201 is less than the thickness of the active material layer 203.

[0056] In other words, in this specific embodiment, the wire groove 201 is only a groove opened on the active material layer 102, and there is no groove on the current collector 101 covered by the active material layer 102. This method does not damage the integrity of the current collector 101 while forming the groove structure, ensures the high support of the current collector 101 layer, reduces the possibility of damage to the current collector 101 layer when subjected to external stress or impact, thereby improving the finished product yield and working stability of the corresponding battery product. For details, please refer to Figure 1 .

[0057] As a specific embodiment, the active material layer 102 includes a first active material layer 102A and a second active material layer 102B, the through hole 202 is a frustum-shaped through hole 202, and the frustum-shaped through hole 202 includes a first hole 202A and a second hole 202B;

[0058] Along the direction of the first active material layer 102A facing the second active material layer 102B, the aperture of the first hole 202A gradually decreases, and the aperture of the second hole 202B gradually increases;

[0059] The first hole 202A and the second hole 202B are arranged adjacent to each other in the perforation area.

[0060] The first active material layer 102A and the second active material layer 102B are layers respectively arranged on two surfaces in the thickness direction of the current collector 101. For details, please refer to Figure 10 , for the convenience of opening holes, the through holes 202 and the auxiliary through holes 203 can be provided by means of laser drilling. However, after the laser enters the electrode plate to form the through holes 202, due to the attenuation of the laser energy, the aperture gradually decreases, and finally a frustum-shaped through hole 202 with different apertures on both sides is formed. The different apertures at both ends of the through hole 202 result in the formation of a yin-yang surface on both sides of the electrode plate, and the aperture difference will further cause the difference in weight loss rate and electrolyte infiltration difference on both sides of the electrode plate. In this preferred embodiment, two through holes 202 with inconsistent opening directions (i.e., the first hole 202A and the second hole 202B) are provided, which can avoid the formation of the yin-yang surface and reduce the difference in weight loss rate and electrolyte infiltration difference on both sides of the electrode plate.

[0061] Furthermore, a plurality of the first holes 202A and a plurality of the second holes 202B are alternately arranged on the perforated area.

[0062] In this preferred embodiment, the truncated cone-shaped through-holes 202 are alternately arranged in an inverted manner. From a process perspective, this means that the holes are staggered on both sides of the electrode sheet. The alternating arrangement of the first holes 202A and the second holes 202B further enhances uniform electrolyte infiltration and improves the structural stability of the electrode sheet. Furthermore, the spacing between adjacent holes on both sides of the current collector 101 is greater than the hole diameter, for example, greater than 100 microns.

[0063] As a specific embodiment, the compaction density of the punching action area within the first radius around the through hole 202 is less than the compaction density of the non-punching action area;

[0064] The compaction density of the punching action area ranges from 0.65 g / cc (grams per cubic centimeter) to 1.9 g / cc, including endpoint values such as any one of 0.650 g / cc, 1.000 g / cc or 1.900 g / cc; and / or the compaction density of the non-punching action area ranges from 0.8 g / cc to 2.0 g / cc, including endpoint values such as any one of 0.80 g / cc, 1.00 g / cc or 2.00 g / cc; and / or the first radius ranges from 15 microns to 70 microns, including endpoint values such as any one of 15.0 microns, 26.3 microns or 70.0 microns. It should be noted that the first radius refers to the radial distance extending outward from the edge of the through hole 202.

[0065] Continuing from the previous section, when laser drilling is used, a heat-affected zone (HAZ) exists around the through-hole 202. The extent of the HZ is related to the laser drilling power parameters. The drilling zone within the first radius can be considered the HZ. Due to the force applied to the hole edges during drilling, the compaction density of the HZ around the hole is lower than that of the non-drilling zone, which is located further away from the drilling area. The non-drilling zone is the area outside the drilling zone. Providing a drilling zone with a lower compaction density on the electrode plate can further improve electrolyte wettability.

[0066] In another specific embodiment, the range of the hole pitch D1 of the through holes 202 is from 200 microns to 500 microns, including the end point values, such as any one of 200.0 microns, 337.5 microns or 500.0 microns; and / or the range of the aperture of the through holes 202 is from 40 microns to 100 microns, including the end point values, such as any one of 40.0 microns, 87.5 microns or 100.0 microns; and / or the range of the ratio of the hole pitch to the aperture is from 4 to 10, including the end point values, such as any one of 4.0, 6.6 or 10.0. The above parameter ranges are the optimal ranges after a large number of theoretical calculations and actual tests. Of course, other ranges can also be selected according to actual situations. For example, the range of the hole pitch of the through holes 202 can be selected to be a larger range of 100 microns to 5000 microns, and the range of the aperture of the through holes 202 can be selected to be a larger range of 20 microns to 150 microns, which is not limited in the present invention; and / or the range of the width of the perforation area is from 0.1 mm to 10 mm, including the end point values, such as any one of 0.10 mm, 2.15 mm or 10.00 mm. The width of the perforation area refers to the width of a single perforation area, such as the width of the first perforation area 220A or the second perforation area 220B, corresponding to W1 in the previous text.

[0067] After punching, the porosity of the electrode plate increases, and the wetting ability with the electrolyte in the battery is greatly improved, reducing the electrochemical polarization impedance of the electrode plate. The porosity can be compared by image analysis. In addition, in the battery, the separator is also a porous material. When the electrode plate is applied to a lithium-ion battery, the electrode plates of the battery are interconnected and short circuit is avoided. Combined with the porosity of the separator, the electrolyte permeability is significantly improved, greatly improving the ion transport efficiency, reducing the battery impedance, and improving the fast charging performance of the battery. When the range of the ratio of the hole pitch to the aperture is between 4 and 10, the separator porosity 35% < φ < 60%. The smaller the ratio of the hole pitch to the aperture, the higher the separator porosity, the lower the impedance of the battery, the better the rate charging performance, and the improved cycle performance.

[0068] The hole depth of the through holes 202 is the thickness of the electrode plate; further, the distance D2 between adjacent wire grooves 201 is from 500 microns to 3000 microns, preferably from 500 microns to 1500 microns. The ratio range of the depth of the wire grooves 201 on one side of the electrode plate to the thickness of the active material layer 102 on this side is 0.1 - 0.6; the range of the distance D3 between the hole farthest from the edge of the electrode plate and the adjacent wire grooves 201 is from 0 to 2000 microns, preferably from 500 microns to 1000 microns. The depth range of the wire grooves 201 is from 5 microns to 30 microns, preferably from 10 microns to 20 microns.

[0069] The through-holes 202 and the wire grooves 201 of the electrode tab are structured in a way that facilitates the accommodation of electrolyte between the tabs, thus ensuring the overall stability of the battery cell. Wiring can significantly improve the battery cycle capacity retention rate, but the cycle expansion increases. The through-hole structure can relieve the expansion in the XY directions, thereby reducing the expansion in the Z direction. Combining these two structures can reduce the expansion of the wired electrode tab during battery cycling, increase reliability, and the large aperture can enhance heat dissipation, improving battery safety. Additionally, the through-hole 202 structure formed by punching on the surface can reduce diaphragm slippage, making the adhesion between the electrode tab and the diaphragm, and between electrode tabs, tighter.

[0070] In addition, the aperture test method is as follows: Observation is carried out using SEM (scanning electron microscope). On the laser incident surface, as the hole depth increases, the aperture gradually decreases. The boundary of the hole can be observed by SEM, so the aperture size can be obtained through measurement. SEM photos are as Figure 11 and Figure 12 shown, where Figure 11 is the laser incident surface of the through-hole 202, Figure 12 is the corresponding exit surface. It is not difficult to see that the apertures of the two surfaces are inconsistent, with one side being 60.34 microns and the other side being 24.85 microns.

[0071] After the current collector 101 is penetrated by laser, holes are formed with obvious edges. Compared with the hole edges of the active layer, the edges of these holes are smoother and have protrusions, which are formed by the melting of the copper foil. This feature can be used to determine whether the current collector 101 has been penetrated, and the depth of the hole can also be tested to determine whether it has reached near the current collector 101.

[0072] Furthermore, the positive and negative electrode tabs are punched simultaneously. Regarding the corresponding relationship of the holes in the positive and negative electrode tabs after punching, it includes the laser incident surfaces of the positive and negative electrodes facing each other, the laser exit surfaces facing each other, the laser incident surface of the positive electrode facing the exit surface of the negative electrode, the laser exit surface of the positive electrode facing the laser incident surface of the negative electrode, and the holes in the positive and negative electrodes being staggered. In addition, the punching aperture of the negative electrode can be greater than, equal to, or less than the punching aperture of the positive electrode tab.

[0073] Generally, the ceramic side of the diaphragm corresponds to the positive electrode. The ceramic layer can help disperse the heat generated inside the battery, reducing the risk of overheating. Furthermore, punching the positive electrode can promote more effective heat transfer. In high-power applications, this helps maintain a stable temperature of the battery, prevent overheating, and improve battery safety. The electrolyte has good wettability in the ceramic layer of the diaphragm. Punching the positive electrode can promote better diffusion and penetration of the electrolyte near the positive electrode, which helps improve the ionic conductivity of the battery, thereby enhancing battery performance and efficiency. Therefore, by improving the diffusion of the electrolyte and heat management through punching the positive and negative electrodes, the stability of the battery can be enhanced, and the risk of abnormal conditions (such as overcharging, over-discharging, etc.) can be reduced.

[0074] The electrode plate provided by the present utility model includes a current collector 101 and an active material layer 102 provided on at least one side of the current collector 101; the surface of the electrode plate includes a perforated area and a wire bonding area 210; the wire bonding area 210 includes at least one wire groove 201; the perforated area includes at least one through hole 202; wherein, the perforated area includes a first perforated area 220A and a second perforated area 220B; along a first direction, the first perforated area 220A and the second perforated area 220B are arranged on both sides of the wire bonding area 210; the through hole 202 penetrates through the current collector 101 and the active material layer 102. By providing the wire groove 201 on the surface of the electrode plate, the present utility model significantly improves the cycle capacity retention rate of the battery. At the same time, in cooperation with the through holes 202 arranged on both sides of the wire groove 201, the cycle expansion of the battery is reduced. At the same time, the setting of the through holes 202 can significantly increase the penetration speed of the electrolyte from the edge of the electrode plate to the center, enabling lithium ions to be transmitted faster, and greatly improving the problem of lithium deposition in the battery. The wire groove 201 has a capillary effect on the electrolyte, making it easier for the electrolyte to fill the wire groove 201, further reducing lithium deposition caused by insufficient electrolyte.

[0075] The present utility model also provides a battery. The structural schematic diagram of a specific embodiment thereof can be referred to the foregoing, which is called the second specific embodiment. The first electrode plate and / or the second electrode plate of the battery is the electrode plate as described in any one of the above.

[0076] The structural technical features of the battery in this specific embodiment can be referred to the technical features of the electrode plate in the foregoing. The present utility model will not repeat them here. In addition, the first electrode plate and the second electrode plate are respectively the positive electrode plate and the negative electrode plate of the battery.

[0077] As a preferred embodiment, the battery is a wound battery;

[0078] The perforated area is arranged at the arc-shaped bending part of the wound battery.

[0079] The wound battery is usually flat and can be divided into an arc-shaped bending part and a straight part. Since the arc-shaped bending part is a bending part formed by planar bending, this part of the battery is subjected to the stress generated by folding, with a greater density, and it is more difficult for the electrolyte to penetrate. In this preferred embodiment, the perforated area is arranged at the arc-shaped bending part of the wound battery, greatly increasing the area of the arc-shaped bending part that can accommodate the electrolyte, further reducing lithium deposition caused by insufficient electrolyte, and thus reducing the cycle expansion of the battery.

[0080] The battery provided by the present utility model, the first electrode tab and / or the second electrode tab of the battery are the electrode tabs as described in any one of the above. For the electrode tab of the present utility model, the surface of the electrode tab includes a perforated area and a wire bonding area 210; the wire bonding area 210 includes at least one wire groove 201; the perforated area includes at least one through hole 202; the through hole 202 penetrates through the electrode tab. By arranging the wire groove 201 on the surface of the electrode tab, the present utility model significantly improves the cycle capacity retention rate of the battery. At the same time, in cooperation with the through hole 202, the cycle expansion of the battery is reduced. At the same time, arranging the through hole 202 can significantly improve the penetration speed of the electrolyte, enabling lithium ions to be transmitted faster, and greatly improving the problem of lithium plating in the battery. And the wire groove 201 has a capillary action on the electrolyte, making it easier for the electrolyte to fill the wire groove 201, further reducing lithium plating caused by insufficient electrolyte.

[0081] Based on the electrode tab scheme in the specific embodiment 1 in the foregoing, embodiments 1 to 4 are set as follows:

[0082] Embodiment 1: The negative electrode tab after rolling and slitting is perforated on the entire surface, with a hole pitch of 0.5 mm, and the rest is the same as in the specific embodiment 1.

[0083] Embodiment 2: The negative electrode tab after rolling and slitting is wire bonded on the entire surface, with a wire pitch of 1 mm, and the rest is the same as in the specific embodiment 1.

[0084] Embodiment 3: The negative electrode tab after rolling and slitting is perforated and wire bonded. The perforated area is the range of 10 mm on both sides of the electrode tab, with a hole pitch of 0.5 mm, and the wire pitch in the wire bonding area 210 is 1 mm. The rest is the same as in the specific embodiment 1.

[0085] Embodiment 4: The negative electrode tab after rolling and slitting is perforated and wire bonded. The perforated area is the range of 10 mm around the electrode tab, with a hole pitch of 0.5 mm, and the wire pitch in the wire bonding area 210 is 1 mm. The rest is the same as in the specific embodiment 1.

[0086] A comparative example 1 produced according to the related art is further provided, including:

[0087] Positive electrode preparation: Lithium cobaltate, a conductive agent (a mixture of conductive carbon black and carbon nanotubes), and PVDF (polyvinylidene fluoride) are placed in NMP (N-methylpyrrolidone) according to a mass ratio of 98.20:1:0.8, stirred evenly to obtain a positive electrode slurry; the positive electrode slurry is evenly coated on both sides of the aluminum foil, and is successively dried, rolled, and punched to obtain a positive electrode tab.

[0088] Preparation of the negative electrode: Artificial graphite (with 25% silicon carbide doped in the graphite), conductive carbon black, styrene-butadiene rubber, and sodium carboxymethyl cellulose were placed in deionized water according to a mass ratio of 94.1:0.5:3:2.4, stirred evenly to obtain a negative electrode slurry; the negative electrode slurry was evenly coated on the negative electrode current collector, and successively subjected to drying, rolling, and slitting treatments, and finally punched to obtain a negative electrode sheet.

[0089] Preparation of the battery: The separator of this application uses a 9.5 μm thick base material + ceramic + coated separator. The electrolyte includes a lithium salt LiPF6 and a solvent, and the solvent includes ethylene carbonate (EC), diethyl carbonate (DEC), and ethyl methyl carbonate (EMC), and the molar ratio of the three is DEC:EC:EMC = 1:1:1. The above-mentioned punched positive electrode sheet, negative electrode sheet, and separator were stacked into a laminated structure battery cell, and after the battery cell was encapsulated, injected with electrolyte, formed, and second-sealed, a lithium-ion battery was obtained.

[0090] The battery cells obtained in Examples 1-4 and Comparative Example 1 were evaluated for their cell capacity, internal resistance, capacity attenuation, and edge lithium deposition (Table 1). By testing the batteries containing the above-mentioned electrode sheets, it can be obtained that compared with Comparative Example 1, the internal resistance, capacity retention rate, and lithium deposition window of Examples 1-4 were all improved, that is, the pore structure of the electrode sheet can reduce the pore tortuosity of the electrode, and can serve as a channel for the rapid diffusion of Li+ inside the electrode sheet, which is beneficial to the rapid diffusion of Li + in the electrode, improve the lithium-ion diffusion coefficient, and is beneficial to enhancing the mass transfer between the positive electrode and the negative electrode and reducing the ionic impedance. On the other hand, it can increase the electrolyte infiltration effect and speed and increase the liquid storage capacity, thereby alleviating edge lithium deposition at the negative electrode and improving the capacity retention rate of the battery. Example 4 had a better cycle retention rate, lower swelling, and improved battery stability compared with Comparative Example 1 and Examples 1-3.

[0091] Table 1

[0092] Group Capacity / mAh Internal Resistance / mΩ Capacity Retention Rate of 200T Cycles (%) Swelling Rate (%) Lithium Stripping Situation of 20T Disassembly Example 1 6249.32 6.98 92.8 12.05 No Lithium Stripping Example 2 6254.73 7.48 94.3 15.50 Slight Lithium Stripping at the Edge Example 3 6255.89 7.34 93.2 13.61 Slight Lithium Stripping at the Edge Example 4 6255.35 7.03 94.1 12.29 No Lithium Stripping Comparative Example 1 6248.4 7.75 91.6 14.74 Severe Lithium Stripping at the Edge

[0093] In this specification, each embodiment is described in a progressive manner. The key points of each embodiment are the differences from other embodiments. For the same or similar parts between each embodiment, reference can be made to each other. For the devices disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the description is relatively simple, and reference can be made to the description in the method part for the relevant parts.

[0094] It should be noted that in this specification, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, such that a process, method, article or device comprising a series of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article or device. Without further limitation, an element defined by the statement "comprising an..." does not exclude the presence of additional identical elements in the process, method, article or device comprising the element.

[0095] The above has introduced in detail the electrode plate and the battery provided by the present utility model. Specific examples are used herein to elaborate on the principle and implementation manner of the present utility model. The description of the above embodiments is only used to help understand the method and its core idea of the present utility model. It should be noted that for those of ordinary skill in the art in this technical field, without departing from the principle of the present utility model, several improvements and modifications can still be made to the present utility model, and these improvements and modifications also fall within the protection scope of the claims of the present utility model.

Claims

1. An electrode tab, characterized in that, It includes a current collector and an active material layer disposed on at least one side of the current collector; the surface of the electrode tab includes a perforated area and a wire bonding area; The wire bonding area includes at least one wire groove; the perforated area includes at least one through hole; Wherein, the perforated area includes a first perforated area and a second perforated area; along a first direction, the first perforated area and the second perforated area are disposed on both sides of the wire bonding area; The through hole penetrates through the current collector and the active material layer.

2. The electrode sheet according to claim 1, wherein, The perforated area further includes a third perforated area and a fourth perforated area; along a second direction, the third perforated area and the fourth perforated area are disposed on both sides of the wire bonding area, and the second direction is perpendicular to the first direction.

3. The electrode tab according to claim 1 or 2, characterized in that, The wire bonding area further includes auxiliary through holes, the wire bonding area includes a plurality of wire grooves, and the auxiliary through holes are disposed within the wire grooves or between two adjacent wire grooves; The auxiliary through holes penetrate through the current collector and the active material layer.

4. The electrode tab according to claim 1, wherein, Along the thickness direction of the electrode tab, the depth of the wire groove is less than the thickness of the active material layer.

5. The electrode tab according to claim 1, characterized in that, The active material layer includes a first active material layer and a second active material layer, the through hole is a frustum-shaped through hole, and the frustum-shaped through hole includes a first hole and a second hole; Along the direction from the first active material layer towards the second active material layer, the aperture of the first hole gradually decreases, and the aperture of the second hole gradually increases; The first hole and the second hole are arranged adjacent to each other in the perforated area.

6. The electrode tab according to claim 5, wherein, A plurality of the first holes and a plurality of the second holes are arranged alternately in the perforated area.

7. The electrode sheet according to claim 1, wherein, The compaction density of the punching action area within a first radius around the through hole is less than the compaction density of the non-punching action area; The compaction density of the punching action area ranges from 0.65 g / cc to 1.9 g / cc, including the end values; and / or the compaction density of the non-punching action area ranges from 0.8 g / cc to 2.0 g / cc, including the end values; The range of the first radius is from 15 microns to 70 microns, including the end values.

8. The electrode tab according to claim 1, wherein The range of the hole pitch of the through hole is from 200 microns to 500 microns, including the end values; and / or the range of the aperture of the through hole is from 40 microns to 100 microns, including the end values; and / or the ratio of the hole pitch to the aperture ranges from 4 to 10, including the end values; and / or the range of the width of the perforated area is from 0.1 mm to 10 mm, including the end values.

9. A battery, characterized in that, The first electrode tab and / or the second electrode tab of the battery is the electrode tab as described in any one of claims 1 to 8.

10. The battery according to claim 9, characterized in that, The battery is a wound battery; The perforated area is disposed at the arc-shaped bending portion of the wound battery.

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