Positive pole piece, sodium ion battery and electric equipment

Abstract

The utility model provides a positive pole piece, a sodium ion battery and electric equipment. The positive pole piece comprises a current collector, a first sub-pole piece and a second sub-pole piece, one side of the first sub-pole piece and / or the second sub-pole piece away from the current collector is provided with a plurality of electrolyte transmission channels extending along a first direction and a second direction, and the length direction of the electrolyte transmission channels extends along the first direction or the second direction. The depth of the electrolyte transmission channel extends in the thickness direction of the sub-pole piece, the depth of the electrolyte transmission channel is 1 / 3-2 / 3 of the thickness of the sub-pole piece, and the first direction and the second direction intersect. Therefore, the transmission distance of the electrolyte in the first direction and the second direction can be shortened, so that the infiltration of the electrolyte on the positive pole piece can be accelerated, the problem of poor wettability of the electrolyte in the positive pole piece is effectively improved, the energy density of the positive pole piece is hardly reduced, and meanwhile, the cycle life of the battery is favorably prolonged.

Description

TECHNICAL FIELD

[0001] The utility model relates to the technical field of battery, specifically, relates to positive pole piece, sodium ion battery and electric equipment. BACKGROUND

[0002] Sodium ion battery as a new type of energy storage technology has the advantages of good low temperature performance, safety and the like. However, the energy density is low. In order to meet the demand of sodium ion battery for energy density, increasing the amount of active material of the electrode sheet of the battery is one of the effective and feasible solutions. The more the amount of active material of the electrode sheet, the thicker the electrode sheet, and the more difficult the transmission of the electrolyte in the electrode sheet, resulting in poorer wettability in the battery and slower wettability in the center of the pole piece. The wettability of the electrolyte of the electrode sheet of the battery is crucial to the performance of the battery. The lower the wettability of the electrolyte, the farther the ion transmission distance between the positive and negative electrodes, and the electrode loses activity in the place not wetted, the interface impedance increases, which seriously affects the cycle and rate performance of the battery. SUMMARY

[0003] The utility model aims at at least in a certain extent solves one of the technical problems among the prior art. For this reason, one purpose of the utility model is to provide a positive pole piece, which can be quickly and completely wetted in the electrolyte.

[0004] In one aspect of the utility model, the utility model provides a positive pole piece. According to the embodiment of the utility model, the positive pole piece comprises: a current collector and a first sub-pole piece and a second sub-pole piece arranged on the two layers of the current collector, the first sub-pole piece and / or the second sub-pole piece has a plurality of electrolyte transmission channels extending along a first direction and extending along a second direction on the side away from the current collector, the length direction of the electrolyte transmission channel extends along the first direction or the second direction, the depth of the electrolyte transmission channel extends to the thickness direction of the sub-pole piece, the depth of the electrolyte transmission channel is 1 / 3-2 / 3 of the thickness of the sub-pole piece, and the first direction and the second direction intersect. In this way, a plurality of staggered electrolyte transmission channels are arranged on the surface of the sub-pole piece (including the first sub-pole piece and the second sub-pole piece), so that the positive pole piece has a multi-dimensional electrolyte transmission channel, the transmission path of the electrolyte is increased, the transmission distance of the electrolyte in the first direction and the second direction is shortened, and then the wettability of the electrolyte to the positive pole piece can be accelerated, the problem of poor wettability of the electrolyte in the positive pole piece is effectively improved, the energy density of the positive pole piece is almost not reduced, and the cycle life of the battery is improved at the same time.

[0005] According to the embodiment of the present application, the first sub-pole piece and / or the second sub-pole piece comprises an edge region and an inner region, the edge region is arranged around the inner region, and the depth of the electrolyte transmission channel located in the inner region is greater than the depth of the electrolyte transmission channel located in the edge region.

[0006] According to the embodiment of the present application, the depth of the electrolyte transmission channel located in the inner region is 10-20 microns deeper than the depth of the electrolyte transmission channel located in the edge region.

[0007] According to the embodiment of the present application, the minimum distance between the boundary line of the sub-pole piece and the boundary line of the edge region is less than or equal to 1 / 5 of the width of the sub-pole piece.

[0008] According to the embodiment of the present application, the distance between the electrolyte transmission channels extending in the same direction and adjacent to each other is greater than or equal to 1 cm.

[0009] According to the embodiment of the present application, the distance between the electrolyte transmission channels extending in the same direction and adjacent to each other is 1-5 cm; and / or, the width of the electrolyte transmission channel is 5-15 microns.

[0010] According to the embodiment of the present application, the electrolyte transmission channel is formed by a punching type and / or a roller shearing type.

[0011] According to the embodiment of the present application, the surface density of the positive pole piece is 300-500 g / m 2 .

[0012] In another aspect of the present application, the present application provides a sodium ion battery. According to the embodiment of the present application, the sodium ion battery comprises the positive pole piece described above. Therefore, the sodium ion battery has better cycle performance. Those skilled in the art can understand that the sodium ion battery has all the features and advantages of the positive pole piece described above, and will not be described in detail here.

[0013] In another aspect of the present application, the present application provides a power consumption equipment. According to the embodiment of the present application, the power consumption equipment comprises the sodium ion battery described above. Therefore, the sodium ion battery has better battery performance. Those skilled in the art can understand that the power consumption equipment has all the features and advantages of the positive pole piece described above, and will not be described in detail here. BRIEF DESCRIPTION OF DRAWINGS

[0014] The above and / or additional aspects and advantages of the present application will become apparent and more readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings, in which:

[0015] Figure 1 is a top view of the positive electrode tab in one embodiment of the present application;

[0016] Figure 2 is Figure 1 is a sectional view along AA' in the above embodiment;

[0017] Figure 3 is a top view of the positive electrode tab in another embodiment of the present application;

[0018] Figure 4 is Figure 3 is a sectional view along AA' in the above embodiment;

[0019] Figure 5 is a schematic diagram of an apparatus for cutting sub-pieces to form electrolyte transmission channels in yet another embodiment of the present application.

[0020] Reference signs: positive electrode tab 100; current collector 30; first sub-piece 10; second sub-piece 20; electrolyte transmission channel 40; edge region S1; inner region S2; roller shearing apparatus 1; punching apparatus 2. DETAILED DESCRIPTION

[0021] The scheme of the present application will be explained below in conjunction with embodiments. Those skilled in the art will understand that the following embodiments are only for illustration of the present application and should not be regarded as limiting the scope of the present application. If no specific technology or condition is specified in the embodiments, the technology or condition described in the literature in the art or according to the product manual is used. If no manufacturer of the reagent or instrument is specified, it is a conventional product that can be obtained from the market.

[0022] The present application will be described below in conjunction with specific embodiments. It should be noted that these embodiments are merely descriptive and do not limit the present application in any way.

[0023] In one aspect of the present application, the present application provides a positive electrode tab. According to the embodiments of the present application, with reference to Figure 1 and Figure 2The positive electrode sheet 100 comprises: a current collector 30 and a first sub-electrode sheet 10 and a second sub-electrode sheet 20 arranged on two layers of the current collector, the first sub-electrode sheet 10 has a plurality of electrolyte transmission channels 40 extending along a first direction X and a second direction Y on the side away from the current collector 30, and / or the second sub-electrode sheet 20 has a plurality of electrolyte transmission channels 40 extending along the first direction X and the second direction Y on the side away from the current collector 30, the length direction of the electrolyte transmission channel 40 extends along the first direction X or the second direction Y, the depth of the electrolyte transmission channel 40 extends to the thickness direction of the sub-electrode sheet, the depth H of the electrolyte transmission channel 40 is 1 / 3-2 / 3 of the thickness D of the sub-electrode sheet, and the first direction X and the second direction Y intersect. In this way, a plurality of electrolyte transmission channels arranged in a staggered manner are arranged on the surface of the sub-electrode sheet (including the first sub-electrode sheet and the second sub-electrode sheet), so that the positive electrode sheet has a multi-dimensional electrolyte transmission channel, increases the transmission path of the electrolyte, shortens the transmission distance of the electrolyte in the first direction and the second direction, and thus can accelerate the infiltration of the electrolyte to the positive electrode sheet, effectively improve the poor infiltration of the electrolyte in the positive electrode sheet, and almost not reduce the energy density of the positive electrode sheet, while being beneficial to improving the cycle life of the battery; and the electrolyte transmission channel 40 can be arranged on one side or both sides of the positive electrode sheet according to actual needs; further, the depth H of the electrolyte transmission channel 40 is 1 / 3-2 / 3 of the thickness D of the sub-electrode sheet, such as H=1 / 3D, H=0.4D, H=0.5D, H=2 / 3D, etc. The electrolyte transmission channel with the above depth can effectively infiltrate the positive electrode sheet, but can also make the sub-electrode sheet have good adhesion and not fall off or break at the electrolyte transmission channel.

[0024] In some embodiments, the first direction and the second direction can be perpendicular to each other, as shown in Figure 1 In this way, the electrolyte transmission channels are arranged in a staggered manner in the first direction and / or the second direction on the surface of the first sub-electrode sheet and / or the second sub-electrode sheet.

[0025] According to some embodiments of the present application, as shown in Figure 1 The spacing s between the electrolyte transmission channels 40 extending in the same direction (such as along the first direction or the second direction) and adjacent to each other is greater than or equal to 1 cm. In this way, the sub-electrode sheet active material separated by the electrolyte transmission channels arranged in a staggered manner has a suitable contact area with the sub-electrode sheet active material not separated by the electrolyte transmission channel at the bottom, so that it is not easy to be peeled off, thereby being beneficial to ensuring the stability of the overall structure of the sub-electrode sheet. According to some specific embodiments of the present application, the spacing s between the electrolyte transmission channels extending in the same direction and adjacent to each other is 1-5 cm, such as 1 cm, 2 cm, 3 cm, 4 cm, 5 cm, etc.

[0026] According to some embodiments of the present application, the width of the electrolyte transmission channel is 5-15 microns, such as 5 microns, 6 microns, 7 microns, 8 microns, 9 microns, 10 microns, 11 microns, 12 microns, 13 microns, 14 microns, 15 microns, etc. In this way, the relatively narrow electrolyte transmission channel can effectively achieve rapid infiltration of the positive electrode sheet, and the relatively narrow width can ensure a large area density of the positive electrode sheet.

[0027] According to some embodiments of the present application, referring to Figure 3 and Figure 4 , the first sub-electrode sheet 10 and / or the second sub-electrode sheet 20 includes an edge region S1 and an internal region S2, the edge region S1 is arranged around the internal region S2 (the internal region of the dashed box in Figure 3 ), the depth H2 of the electrolyte transmission channel 40 located in the internal region S2 is greater than the depth H1 of the electrolyte transmission channel 40 located in the edge region S1, that is, H2 is greater than H1. In this way, the electrolyte transmission channel with a greater depth is arranged in the relatively central region of the positive electrode sheet, which can further accelerate the infiltration speed of the internal region S2 of the positive electrode sheet, better ensure the infiltration of the electrolyte on the entire positive electrode sheet, and improve the cycle and other battery performance of the battery.

[0028] According to some embodiments of the present application, the depth H2 of the electrolyte transmission channel 40 located in the internal region S2 is 10-20 microns deeper than the depth H1 of the electrolyte transmission channel 40 located in the edge region S1, that is, H2-H1=10-20 microns, such as 10 microns, 11 microns, 12 microns, 13 microns, 14 microns, 15 microns, 16 microns, 17 microns, 18 microns, 19 microns, 20 microns, etc. In this way, the electrolyte transmission channel with a greater depth is arranged in the relatively central region of the positive electrode sheet, which can further accelerate the infiltration speed of the internal region S2 of the positive electrode sheet, better ensure the infiltration of the electrolyte on the entire positive electrode sheet, and improve the cycle and other battery performance of the battery.

[0029] According to some embodiments of the present application, as shown in Figure 3 , the minimum distance h between the boundary line (the dashed line in Figure 3 ) of the edge region S1 and the internal region S2 and the boundary line of the sub-electrode sheet (for example, the first sub-electrode sheet 10 in Figure 3 ) is less than or equal to 1 / 5 of the width d of the sub-electrode sheet. In this way, the electrolyte transmission channel with a greater depth can be arranged in a specific internal region, and the electrolyte transmission channel with a shallower depth can be arranged in a specific edge region. In this way, not only can the relatively central internal region of the sub-electrode sheet be rapidly infiltrated by the electrolyte, but also the overall adhesion of the sub-electrode sheet can be better ensured, so that the sub-electrode sheet is not easy to fall off from the current collector, thereby improving the stability of the positive electrode sheet and the battery.

[0030] It should be noted that the width d of the sub-pole piece refers to the length of the smaller dimension of the sub-pole piece, such as Figure 3 The length of the sub-pole piece in the second direction Y direction is the width of the sub-pole piece.

[0031] According to some embodiments of the present application, the surface density of the positive pole piece (i.e. the surface density of both sides) is 300-500 g / m 2 , such as 300 g / m 2 , 320 g / m 2 , 350 g / m 2 , 380 g / m 2 , 400 g / m 2 , 420 g / m 2 , 450 g / m 2 , 470 g / m 2 , 500 g / m 2 , etc. Due to the setting of the electrolyte transmission channel in the present application, the electrolyte is accelerated to infiltrate the positive pole piece. In order to further improve the energy density of the positive pole piece and the battery, the surface density of the positive pole piece can be further improved, that is, the amount of active material of the positive pole piece is increased, and a thicker positive pole piece is prepared. Therefore, the technical scheme of the present application can not only accelerate the infiltration of the electrolyte into the positive pole piece, but also improve the surface density of the positive pole piece to 300-500 g / m 2 , thereby improving the energy density of the battery.

[0032] Those skilled in the art can understand that the surface density of the positive pole piece mentioned above refers to the surface density after the electrolyte transmission channel is formed.

[0033] In some embodiments, due to the small size (width and depth) of the electrolyte transmission channel, the surface density of the positive pole piece after the electrolyte transmission channel is formed is less than the coating surface density of the positive pole piece (i.e. before the electrolyte transmission channel is cut), which is within about 1%. Therefore, the waste of positive pole paste can be greatly reduced.

[0034] According to some embodiments of the present application, the electrolyte transmission channel 40 is cut by a punching type and / or a roller shearing type. In some embodiments, as shown in Figure 5 , the roller shearing type equipment 1 is used to cut the electrolyte transmission channel 40 in the first direction by a blade, and the punching type equipment 2 is used to cut the electrolyte transmission channel 40 in the second direction by a blade.

[0035] According to the embodiments of the present application, the materials of the first sub-pole piece and the second sub-pole piece in the positive pole piece do not have special requirements, and a person skilled in the art can flexibly select according to actual needs. In some embodiments, the slurry forming the first sub-pole piece and the second sub-pole piece includes positive active material, conductive agent, binder, solvent and other components. The positive pole slurry is coated on both sides of the current collector, and after heating and curing, the first sub-pole piece and the second sub-pole piece without electrolyte transmission channels can be obtained. In some examples, the positive active material can include one or a mixture of several of layered transition metal oxides, polyanion materials, and Prussian blue. The conductive agent can include at least one of superconducting carbon, acetylene black, carbon black, ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers. The binder can include at least one of polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), vinylidene fluoride-tetrafluoroethylene-propylene terpolymer, vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene terpolymer, tetrafluoroethylene-hexafluoropropylene copolymer, and fluorine-containing acrylic ester resin.

[0036] In some embodiments, the current collector can be an electrically conductive material such as aluminum foil.

[0037] In another aspect of the present application, the present application provides a sodium ion battery. According to the embodiments of the present application, the sodium ion battery includes the positive pole piece described above. Therefore, the sodium ion battery has better cycle performance. A person skilled in the art can understand that the sodium ion battery has all the features and advantages of the positive pole piece described above, and will not be described in detail here.

[0038] A person skilled in the art can understand that the sodium ion battery, in addition to the above-mentioned positive pole piece, also includes structures or components necessary for conventional sodium ion batteries, such as isolation membranes, negative pole pieces, electrolytes, tabs, soft packages, housings, and the like.

[0039] In another aspect of the present application, the present application provides a sodium ion battery. According to the embodiments of the present application, the sodium ion battery includes the positive pole piece described above. Therefore, the sodium ion battery has better cycle performance. A person skilled in the art can understand that the sodium ion battery has all the features and advantages of the positive pole piece described above, and will not be described in detail here.

[0040] According to the embodiments of the present application, the specific type of the electric equipment does not have special requirements, and a person skilled in the art can flexibly select according to actual needs, such as the electric equipment including but not limited to mobile phones, computers, notebooks, game consoles, cars, and all kinds of electric equipment.

[0041] Embodiments

[0042] Embodiment 1

[0043] First, 97 parts by mass of sodium nickel manganese acid, 1.5 parts by mass of polyvinylidene fluoride, 0.9 parts by mass of carbon black, and 0.6 parts by mass of carbon nanotubes are added to NMP (N-methyl-2-pyrrolidone) and dispersed and stirred to coat both sides of the positive current collector, and a conventional positive electrode sheet is obtained after drying;

[0044] Second, the positive electrode sheet is rolled to obtain a sub-electrode sheet with a single-side powder thickness of 95 microns;

[0045] Third, the height of the blade cutting is set, the depth of cutting into the edge area of the first sub-electrode sheet is 31.6 microns (i.e. the depth of the electrolyte transmission channel is 31.6 microns), the depth of cutting into the internal area of the first sub-electrode sheet is 41.6 microns (i.e. the depth of the electrolyte transmission channel is 41.6 microns), and the distance between the blades is set to 5 cm (the distance s between adjacent electrolyte transmission channels is 5 cm); when the positive electrode sheet is conveyed on the platform, the cutting knife parallel to the conveying direction cuts a horizontal cut on the surface of the first sub-electrode sheet, and when the electrode sheet stops, the cylinder pushes the blade downward to cut a vertical cut on the surface of the first sub-electrode sheet;

[0046] Fourth, the reverse side is turned over to cut the horizontal and vertical staggered cuts in the same way, i.e. a positive electrode sheet with horizontal and vertical staggered electrolyte transmission channels on both sides is obtained, and the areal density of the positive electrode sheet is 300 g / m 2 .

[0047] Example 2

[0048] First, 97 parts by mass of sodium nickel manganese acid, 1.5 parts by mass of polyvinylidene fluoride, 0.9 parts by mass of carbon black, and 0.6 parts by mass of carbon nanotubes are added to NMP (N-methyl-2-pyrrolidone) and dispersed and stirred to coat both sides of the positive current collector, and a conventional positive electrode sheet is obtained after drying;

[0049] Second, the positive electrode sheet is rolled to obtain a sub-electrode sheet with a single-side powder thickness of 95 microns;

[0050] Third, the height of the blade cutting is set, the depth of cutting into the edge area of the first sub-electrode sheet is 47.5 microns, the depth of cutting into the internal area of the first sub-electrode sheet is 57.5 microns, and the distance between the blades is set to 5 cm (the distance s between adjacent electrolyte transmission channels is 5 cm); when the positive electrode sheet is conveyed on the platform, the cutting knife parallel to the conveying direction cuts a horizontal cut on the surface of the first sub-electrode sheet, and when the electrode sheet stops, the cylinder pushes the blade downward to cut a vertical cut on the surface of the first sub-electrode sheet;

[0051] Fourth, the reverse side is turned over to cut the horizontal and vertical staggered cuts in the same way, i.e. a positive electrode sheet with horizontal and vertical staggered electrolyte transmission channels on both sides is obtained, and the areal density of the positive electrode sheet is 300 g / m 2 .

[0052] Example 3

[0053] First, 97 parts by mass of sodium nickel manganese acid, 1.5 parts by mass of polyvinylidene fluoride, 0.9 parts by mass of carbon black, and 0.6 parts by mass of carbon nanotubes were added to NMP (N-methyl-2-pyrrolidone) and dispersed and stirred to coat both sides of the positive current collector, and a conventional positive electrode sheet was obtained after drying;

[0054] Second, the positive electrode sheet was rolled to obtain a sub-electrode sheet with a single-side powder thickness of 95 microns;

[0055] Third, the height of the blade cutting was set, the depth of cutting into the edge region of the first sub-electrode sheet was 63.3 microns, the depth of cutting into the internal region of the first sub-electrode sheet was 73.3 microns, and the distance between the blades was set to 5 cm (the distance s between adjacent electrolyte transmission channels was 5 cm); when the positive electrode sheet was conveyed on the platform, the cutting knife parallel to the conveying direction cut a horizontal cut on the surface of the first sub-electrode sheet, and when the electrode sheet stopped, the cylinder pushed the blade downward to cut a vertical cut on the surface of the first sub-electrode sheet;

[0056] Fourth, the reverse side was turned over to cut the horizontal and vertical staggered cuts in the same way, i.e., a positive electrode sheet with horizontal and vertical staggered electrolyte transmission channels on both sides was obtained, and the areal density of the positive electrode sheet was 300 g / m 2 .

[0057] Example 4

[0058] First, 97 parts by mass of sodium nickel manganese acid, 1.5 parts by mass of polyvinylidene fluoride, 0.9 parts by mass of carbon black, and 0.6 parts by mass of carbon nanotubes were added to NMP (N-methyl-2-pyrrolidone) and dispersed and stirred to coat both sides of the positive current collector, and a conventional positive electrode sheet was obtained after drying;

[0059] Second, the positive electrode sheet was rolled to obtain a sub-electrode sheet with a single-side powder thickness of 95 microns;

[0060] Third, the height of the blade cutting was set, the depth of cutting into the edge region of the first sub-electrode sheet was 63.3 microns, the depth of cutting into the internal region of the first sub-electrode sheet was 73.3 microns, and the distance between the blades was set to 3 cm (the distance s between adjacent electrolyte transmission channels was 3 cm); when the positive electrode sheet was conveyed on the platform, the cutting knife parallel to the conveying direction cut a horizontal cut on the surface of the first sub-electrode sheet, and when the electrode sheet stopped, the cylinder pushed the blade downward to cut a vertical cut on the surface of the first sub-electrode sheet;

[0061] Fourth, the reverse side was turned over to cut the horizontal and vertical staggered cuts in the same way, i.e., a positive electrode sheet with horizontal and vertical staggered electrolyte transmission channels on both sides was obtained, and the areal density of the positive electrode sheet was 300 g / m 2 .

[0062] Example 5

[0063] First, 97 parts by mass of sodium nickel manganese acid, 1.5 parts by mass of polyvinylidene fluoride, 0.9 parts by mass of carbon black, and 0.6 parts by mass of carbon nanotubes were added to NMP (N-methyl-2-pyrrolidone) and dispersed and stirred to coat both sides of the positive current collector, and a conventional positive electrode sheet was obtained after drying;

[0064] Second, the positive electrode sheet was rolled to obtain a sub-electrode sheet with a single-side powder thickness of 95 microns;

[0065] Third, the height of the blade cutting was set, the depth of cutting into the edge region of the first sub-electrode sheet was 63.3 microns, the depth of cutting into the internal region of the first sub-electrode sheet was 73.3 microns, and the distance between the blades was set to 1 cm (the distance s between adjacent electrolyte transmission channels was 1 cm); when the positive electrode sheet was conveyed on the platform, the cutting knife parallel to the conveying direction cut a horizontal cut on the surface of the first sub-electrode sheet, and when the electrode sheet stopped, the cylinder pushed the blade downward to cut a vertical cut on the surface of the first sub-electrode sheet;

[0066] Fourth, the reverse side was turned over to cut horizontal and vertical staggered cuts in the same way, i.e., a positive electrode sheet with horizontal and vertical staggered electrolyte transmission channels on both sides was obtained, and the areal density of the positive electrode sheet was 300 g / m 2 .

[0067] Example 6

[0068] First, 97 parts by mass of sodium nickel manganese acid, 1.5 parts by mass of polyvinylidene fluoride, 0.9 parts by mass of carbon black, and 0.6 parts by mass of carbon nanotubes were added to NMP (N-methyl-2-pyrrolidone) and dispersed and stirred to coat both sides of the positive current collector, and a conventional positive electrode sheet was obtained after drying;

[0069] Second, the positive electrode sheet was rolled to obtain a sub-electrode sheet with a single-side powder thickness of 95 microns;

[0070] Third, the height of the blade cutting was set, the depth of cutting into the edge region of the first sub-electrode sheet was 47.5 microns, the depth of cutting into the internal region of the first sub-electrode sheet was 57.5 microns, and the distance between the blades was set to 1 cm (the distance s between adjacent electrolyte transmission channels was 1 cm); when the positive electrode sheet was conveyed on the platform, the cutting knife parallel to the conveying direction cut a horizontal cut on the surface of the first sub-electrode sheet, and when the electrode sheet stopped, the cylinder pushed the blade downward to cut a vertical cut on the surface of the first sub-electrode sheet;

[0071] Fourth, the reverse side was turned over to cut horizontal and vertical staggered cuts in the same way, i.e., a positive electrode sheet with horizontal and vertical staggered electrolyte transmission channels on both sides was obtained, and the areal density of the positive electrode sheet was 300 g / m 2 .

[0072] Example 7

[0073] The difference from Example 4 is that the blade incision depth in the sub-pole piece is 63.3 microns.

[0074] Comparative Example 1

[0075] The difference from Example 1 is that the sub-pole piece has no incision, that is, no electrolyte transmission channel is provided.

[0076] The electrolyte is injected into the positive electrode pole piece in the examples and the control examples, the electrolyte infiltration time of the positive electrode pole piece is tested, and the application of the positive electrode pole piece is tested. Assembled battery, test the capacity retention rate of the battery after the cycle test, and the test results are shown in Table 1.

[0077] Table 1

[0078] Scheme Pole piece area (cm*cm) Infiltration time (min) Cycling 500 cycles capacity retention rate (%) Example 1 20*20 84 95.28 Example 2 20*20 74 95.36 Example 3 20*20 44 95.54 Example 4 20*20 20 96.83 Example 5 20*20 6 97.76 Example 6 20*20 40 95.74 Example 7 20*20 32 96.44 Comparative Example 1 20*20 180 94.53

[0079] According to the test results of Examples 1-7 and Comparative Example 1, the present application cuts the incisions in the pole piece, which can effectively reduce the electrolyte infiltration time and improve the cycle performance.

[0080] As can be seen from the test results of Examples 1 to 3, as the incision depth in the sub-pole piece increases, that is, as the depth of the electrolyte transmission channel increases, the electrolyte infiltration time of the positive electrode pole piece gradually shortens;

[0081] As can be seen from the test results of Examples 3 to 5, as the distance between the blades decreases, that is, as the distance between the adjacent electrolyte transmission channels decreases, the electrolyte infiltration time of the positive electrode pole piece gradually shortens;

[0082] As can be seen from the test results of Examples 4 and 7, adjusting the blade cutting thickness corresponding to the internal region of the sub-pole piece, so that the incision depth of the internal region of the sub-pole piece is relatively deeper than the edge region of the sub-pole piece, can help to achieve the effect of accelerating the infiltration speed of the internal region of the pole piece, and help to reduce the infiltration time and improve the cycle performance.

[0083] The terms "first", "second" in the present application are only for the purpose of description, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined with "first", "second" can explicitly or implicitly include one or more of the features. In the description of the present application, the meaning of "multiple" is two or more, unless otherwise specifically limited.

[0084] In the description of the present specification, the description referring to the terms "one embodiment", "some embodiments", "an example", "a specific example", or "some examples" and the like means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In the present specification, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any appropriate manner in any one or more embodiments or examples. Furthermore, the person skilled in the art can combine and combine the different embodiments or examples described in the present specification and the features of the different embodiments or examples, without contradiction.

[0085] Although the embodiments of the present application have been shown and described above, it should be understood that the above-described embodiments are exemplary and should not be construed as limiting the present application, and those skilled in the art can make changes, modifications, replacements and variations to the above-described embodiments within the scope of the present application.

Claims

1. A positive electrode sheet, characterized by, The positive electrode plate comprises: a current collector and a first sub-pole piece and a second sub-pole piece arranged on two layers of the current collector, the first sub-pole piece and / or the second sub-pole piece having a plurality of electrolyte transmission channels extending in a first direction and extending in a second direction on the side away from the current collector, the length direction of the electrolyte transmission channels extending in the first direction or the second direction, the depth of the electrolyte transmission channels extending in the thickness direction of the sub-pole piece, the depth of the electrolyte transmission channels being 1 / 3-2 / 3 of the thickness of the sub-pole piece, and the first direction and the second direction intersecting.

2. The cathode electrode of claim 1, wherein, The first sub-pole piece and / or the second sub-pole piece comprises an edge region and an inner region, the edge region being arranged around the inner region, the depth of the electrolyte transmission channels in the inner region being greater than the depth of the electrolyte transmission channels in the edge region.

3. The cathode electrode of claim 2, wherein, The depth of the electrolyte transmission channels in the inner region is 10-20 microns deeper than the depth of the electrolyte transmission channels in the edge region.

4. The positive electrode plate of claim 2 or 3, wherein, The minimum distance between the boundary line of the edge region and the boundary line of the inner region is less than or equal to 1 / 5 of the width of the sub-pole piece.

5. The positive electrode sheet according to any one of claims 1 to 3, characterized by The spacing between the electrolyte transmission channels extending in the same direction and adjacent to each other is greater than or equal to 1 cm.

6. The cathode electrode of claim 5, wherein, The spacing between the electrolyte transmission channels extending in the same direction and adjacent to each other is 1-5 cm. And / or, the width of the electrolyte transmission channels is 5-15 microns.

7. The positive electrode sheet according to any one of claims 1 to 3, characterized by The electrolyte transmission channels are formed by stamping and / or roll shearing.

8. The positive electrode plate of any one of claims 1-3, wherein, The face density of the positive electrode plate is 300-500 g / m 2 .

9. A sodium-ion battery, characterized in that, The positive electrode plate comprises:

10. An electric device, characterized by The sodium ion battery comprises: The sodium ion battery comprises:

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