Pole piece, preparation method of pole piece, battery and carrier

Abstract

The invention relates to the technical field of new energy batteries, and discloses a pole piece, a preparation method of the pole piece, a battery and a carrier, the pole piece comprises a current collector and a first active substance layer which are sequentially stacked in the thickness direction, the first active substance layer comprises a first material area and a second material area which are sequentially arranged in the first direction, and the second material area contains a silicon material; a groove structure is arranged between the first material area and the second material area. The specific area of the first active material layer is coated with the silicon-containing material, so that the specific capacity of the material is improved on the basis of not increasing the coating thickness, the battery is ensured to have relatively high energy density, and a series of problems caused by over-thick pole pieces are avoided. And the gap is reserved around the silicon-containing material region, which is equivalent to reserving an expansion space for the silicon material, so that the expansion of the silicon material in the thickness direction can be relieved, the damage to the pole piece is reduced, and the cycle life of the battery is prolonged. In addition, the groove structure is also beneficial to improving the electrolyte infiltration effect and improving the battery performance.

Description

Technical Field

[0001] The present invention relates to the technical field of new energy batteries, and in particular to a pole piece, a method for preparing the pole piece, a battery and a carrier. Background Art

[0002] With the widespread application of lithium-ion batteries in electric vehicles, rail transit, energy storage and other fields, the demand for lithium-ion battery technology with high energy density and long cycle life is also increasing.

[0003] In order to improve the energy density of the battery, one of the traditional methods is to increase the coating load of the battery pole piece, that is, to increase the coating thickness. However, the increase in pole piece thickness will cause a series of problems such as longer lithium ion transmission path and insufficient electrolyte infiltration, which will eventually lead to a decline in battery performance.

[0004] In order to solve the problem of excessive thickness of the electrode, the industry currently usually adopts the method of doping the active material with materials with high specific capacity, such as silicon materials. Silicon materials can effectively improve battery performance and reduce battery thickness to a certain extent.

[0005] However, due to the lithium storage mechanism of silicon materials, there is a serious volume effect, that is, the pole piece has a large volume expansion, especially the expansion in the thickness direction will cause irreversible damage to the pole piece, resulting in the breakage of material particles and the destruction of electrode structure, causing the active material to separate from the conductive agent and cause deactivation. In addition, the large volume expansion will also cause the SEI film (Solid Electrolyte Interface) to grow repeatedly, consume active lithium ions, and affect the cycle life of the battery. Summary of the invention

[0006] The present invention provides a pole piece, a method for preparing the pole piece, a battery and a carrier, so as to solve or improve the problem in the related art that silicon material is doped into the active material of the battery pole piece, resulting in serious volume expansion, especially expansion in the thickness direction, which will cause irreversible damage to the pole piece and affect the battery cycle life.

[0007] In a first aspect, the present invention provides a battery, comprising a current collector and a first active material layer stacked in sequence along a thickness direction thereof, the first active material layer comprising a first material region and a second material region arranged in sequence along a first direction, the second material region comprising a silicon material, and a groove structure is arranged between the first material region and the second material region to form a gap on a side of the first material region and the second material region away from the current collector.

[0008] In an optional embodiment, the first material area and the second material area are configured as long strip areas extending along the second direction.

[0009] In an optional embodiment, there are multiple first material areas and multiple second material areas respectively, and along the first direction, the multiple first material areas and the multiple second material areas are alternately distributed in sequence, and the groove structure is provided between adjacent first material areas and second material areas.

[0010] In an optional embodiment, the sizes of the plurality of second material regions along the first direction are all the same, and the distances between two adjacent second material regions along the first direction are all the same.

[0011] In an optional implementation, it also includes:

[0012] The second active material layer is stacked on a side of the first active material layer away from the current collector.

[0013] In an optional embodiment, the dimension of the groove structure along the first direction is w 1 μm, the particle size of the active material in the second active material layer is d μm;

[0014] Among them, w 1 <d, and / or, 1≤d≤10.

[0015] In an optional embodiment, in one of the pole pieces, the mass of the silicon material in the first active material layer is m 1 kg, and the sum of the masses of the active materials in the first active material layer and the second active material layer is m 2 kg, of which 1% ≤ m 1 / m 2 ≤5%.

[0016] In an optional embodiment, the thickness of the first active material layer is T 1 μm, the depth of the groove structure is H μm, and the thickness of the second active material layer is T 2 μm;

[0017] Among them, 60≤T 1 ≤150;

[0018] and / or, 50% ≤ H / T 1 ≤80%;

[0019] and / or, 40 ≤ T 2 ≤100.

[0020] In a second aspect, the present invention further provides a method for preparing a pole piece as described in any one of the above items, comprising:

[0021] Performing zone coating on the surface of the current collector to form a first active material layer; wherein the first active material layer includes a first material zone and a second material zone, and the second material zone includes a silicon material;

[0022] Performing etching and scribing between the first material region and the second material region to form a groove structure;

[0023] A coating is performed on the surface of the first active material layer to form a second active material layer.

[0024] In an optional embodiment, before the step of coating the surface of the first active material layer, the method further comprises:

[0025] The etched first active material layer is rolled to make the size of the groove structure along the first direction reach a preset size.

[0026] In a third aspect, the present invention further provides a battery pack, comprising a battery cell, wherein the battery cell comprises a positive electrode sheet, a negative electrode sheet, and a separator arranged between the positive electrode sheet and the negative electrode sheet, wherein the negative electrode sheet is configured as a electrode sheet as described in any one of the above items.

[0027] In a fourth aspect, the present invention further provides a vehicle comprising the battery as described above.

[0028] The pole piece provided by the present invention, by coating the silicon-containing material in the designated area of ​​the first active material layer, improves the specific capacity of the material without increasing the coating thickness, ensures that the battery has a high energy density, and avoids a series of problems caused by the excessive thickness of the pole piece. And leaving a gap around the silicon-containing material area is equivalent to reserving expansion space for the silicon material, which can alleviate the expansion of the silicon material in the thickness direction, improve the problem of large cyclic expansion of the pole piece, reduce damage to the pole piece, and increase the cycle life of the battery. In addition, the groove structure is also conducive to increasing the infiltration effect of the electrolyte and improving the performance of the battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0030] Figure 1 A schematic diagram of the structure of a pole piece according to an embodiment of the present invention;

[0031] Figure 2 for Figure 1 A partial enlarged schematic diagram of the first active material layer;

[0032] Figure 3 A partial schematic diagram of a first active material layer and a second active material layer according to an embodiment of the present invention;

[0033] Figure 4 is a schematic structural diagram of a first active material layer according to an embodiment of the present invention;

[0034] Figure 5 for Figure 4 A local enlarged schematic diagram of the groove structure in FIG.

[0035] Figure 6 Schematic diagram of the structure of a coating die head according to an embodiment of the present invention.

[0036] Description of reference numerals:

[0037] 1. Current collector; 2. First active material layer; 201. First material area; 202. Second material area; 203. Groove structure; 3. Second active material layer; 4. Coating die; 401. Upper die; 4011. First feed channel; 4012. Second feed channel; 402. Lower die; 4021. Liquid storage tank; 403. Gasket. DETAILED DESCRIPTION

[0038] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0039] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0040] In the description of the present invention, "plurality" means two or more. In addition, the terms "first", "second", and "third" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0041] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0042] Combine the following Figures 1 to 6 , describing the pole piece, pole piece preparation method, battery and carrier of the embodiments of the present invention.

[0043] According to an embodiment of the present invention, on the one hand, a pole piece is provided, such as Figure 1 As shown, the pole piece includes a current collector 1 and a first active material layer 2 which are sequentially stacked along the thickness direction. The first active material layer 2 includes a first material region 201 and a second material region 202 which are sequentially arranged along the first direction, and the second material region 202 includes silicon material. Figure 2 As shown, a groove structure 203 is provided between the first material region 201 and the second material region 202 to form a gap on the side of the first material region 201 and the second material region 202 facing away from the current collector 1 .

[0044] It should be noted that the expansion of silicon material is theoretically in random directions, and the expansion along the thickness direction of the electrode is particularly unfavorable. On the one hand, severe expansion will cause the thickness of the electrode to increase, and the transmission path of lithium ions will also increase accordingly; on the other hand, severe expansion will cause the pressure inside the battery to increase, greatly increasing the risk of short circuit and battery rupture.

[0045] In the embodiment of the present invention, by coating the silicon-containing material in the designated area of ​​the first active material layer 2, the specific capacity of the material is improved without increasing the coating thickness, ensuring that the battery has a high energy density and avoiding a series of problems caused by excessive thickness of the pole piece. At the same time, a gap is left around the silicon-containing material area, which is equivalent to reserving expansion space for the silicon material in a direction perpendicular to the thickness of the pole piece, thereby alleviating the expansion of the silicon material in the thickness direction, improving the problem of large cyclic expansion of the pole piece, thereby reducing damage to the pole piece and improving the cycle life of the battery. In addition, the provision of the groove structure 203 is also conducive to increasing the infiltration effect of the electrolyte and improving the performance of the battery.

[0046] Specifically, in some embodiments of the present invention, Figure 4 As shown, the first material area 201 and the second material area 202 are configured as long strip areas extending along the second direction. Preferably, the groove structure 203 is annular and surrounds the long strip second material area 202 .

[0047] This arrangement facilitates the application of different slurries on the surface of the current collector 1 in different areas, facilitates the preparation of the pole piece, facilitates mass production, and speeds up the production cycle. It should be noted that the thickness direction, the first direction, and the second direction intersect each other. Specifically, in this embodiment, the thickness direction, the first direction, and the second direction are perpendicular to each other.

[0048] Further, in some embodiments of the present invention, Figure 4 As shown, there are a plurality of first material regions 201 and a plurality of second material regions 202. Along the first direction, the plurality of first material regions 201 and the plurality of second material regions 202 are alternately distributed in sequence, and as shown in FIG. Figure 5 As shown, a groove structure 203 is disposed between adjacent first material regions 201 and second material regions 202 .

[0049] Such arrangement ensures that the material has a high specific capacity while dispersing the silicon material into a plurality of designated areas, and a groove structure 203 is provided around each silicon material area, thereby providing better expansion space for the silicon material, fully alleviating the expansion along the thickness direction, reducing the irreversible damage to the pole piece caused by the expansion in the thickness direction, and being beneficial to improving the cycle life of the battery.

[0050] Preferably, in some embodiments of the present invention, Figure 2 As shown, the size w of the plurality of second material regions 202 along the first direction is 2 are the same, and along the first direction, the spacing K between two adjacent second material regions 202 is the same.

[0051] In this way, the size consistency and spacing consistency of multiple second material areas 202 along the first direction provide uniformity and predictability for the entire structure, facilitate partition coating and etching and scribing to form a groove structure 203, achieve a more efficient and precise manufacturing process, and make the pole piece highly repeatable and regular, which facilitates the die-cutting of the pole piece into pieces and avoids the phenomenon of uneven pole piece quality. It is suitable for application scenarios that require precise control of material layout and spacing.

[0052] Further, in an embodiment of the present invention, if Figure 1 As shown, the pole piece further includes a second active material layer 3, which is stacked on the side of the first active material layer 2 away from the current collector 1. That is, along the thickness direction, the current collector 1, the first active material layer 2 and the second active material layer 3 are stacked in sequence, and in the first active material layer 2, each second material area 202 containing silicon material is surrounded by a groove structure 203.

[0053] In this way, the second active material layer 3 covers the first active material layer 2, so that the upper active material layer and the lower active material layer with the cavity area have good "bonding" properties, so that the upper and lower active material layers are equivalent to forming a "frame" that limits the expansion of the silicon material in the thickness direction. Since there is a "frame" that limits the expansion of the silicon material in the thickness direction, and the cavity formed by the groove structure 203 is reserved around the silicon material, the silicon material will preferentially expand and extrude into the surrounding groove structure 203, which is equivalent to a directional design for the expansion of the silicon material, thereby effectively reducing the expansion in the thickness direction, greatly reducing the damage to the pole piece, and fully improving the performance of the battery.

[0054] In addition, a second active material layer 3 is coated on top of the first active material layer 2 doped with silicon material, which can effectively make up for the kinetic deficiency caused by adding silicon material while improving the energy density of the battery.

[0055] In an optional embodiment of the present invention, Figure 2 As shown, the dimension of the groove structure 203 along the first direction is w 1 μm, and the particle size of the active material in the second active material layer 3 is d μm. 1 and d satisfies: w 1 <d. In this way, after coating the second active material layer 3, the active material particles in the second active material layer 3 will not "invade" the groove structure 203, thereby ensuring reliable expansion space for the silicon material.

[0056] In addition, d satisfies: 1≤d≤10. For example, d can be 1, 6, 8, 10, or a value between any two values. This is only an example and is not specifically limited. In this way, the particle size of the active material is smaller, which is beneficial to shorten the transmission path of lithium ions and improve the fast charging capability of the battery. If the particle size of the active material is too large, such as d is greater than 10, the transmission path of lithium ions will increase, affecting the fast charging capability of the battery. If the particle size of the active material is too small, such as d is less than 1, it is not convenient to process the groove structure 203, affecting the battery performance. It can be understood that according to the particle size of the active material in the second active material layer 3, the size of the groove structure 203 along the first direction is reasonably designed, that is, according to the value of d in the preset range, w is reasonably selected. 1 The numerical value of is not specifically limited here.

[0057] In some embodiments of the present invention, in a pole piece, the mass of the silicon material in the first active material layer 2 is m 1 kg, and the sum of the masses of the active materials in the first active material layer 2 and the second active material layer 3 is m 2 kg, of which 1% ≤ m 1 / m 2≤5%. That is, in each electrode, the mass of silicon material accounts for 1% to 5% of the total mass of negative electrode active material. For example, m 1 / m 2 It can be 1%, 3%, 4%, 5%, or any value between any two values. This is only an example and is not a specific limitation.

[0058] This can effectively increase the energy density of the battery while reducing the coating thickness. 1 / m 2 If the amount of silicon material added is too much, such as m 1 / m 2 If it is greater than 5%, more gaps will be needed to accommodate the expansion of the silicon material. However, too many gaps will lead to a decrease in the bonding performance of the electrode and the conductivity, thus affecting the battery performance.

[0059] Further, in an optional embodiment of the present invention, as Figure 2 As shown, the thickness of the first active material layer 2 is T 1 μm, and the depth of the groove structure 203 is H μm. Figure 1 As shown, the thickness of the second active material layer 3 is T 2 μm. Specifically, T 1 Satisfy: 60≤T 1 ≤150.T 2 Satisfy: 40 ≤ T 2 ≤100. For example, T 1 It can be 60, 80, 120, 150, or any value between two values; T 2 It can be 40, 50, 80, 100, or any value between any two values; this is only an example and is not a specific limitation.

[0060] In this way, by controlling the coating thickness of the first active material layer 2 and the second active material layer 3, the capacity density of the battery can be improved to meet the 4C-6C fast charging capacity of the battery cell. 1 Less than 60, T 2 If the active material layer is thicker, such as T 1 Greater than 150, T 2 If it is greater than 100, the thickness of the electrode will increase. Too thick an electrode will increase the lithium ion transmission path and reduce the charge and discharge cycle capacity.

[0061] In addition, in the embodiment of the present invention, H and T 1 The ratio meets: 50% ≤ H / T 1≤80%. For example, H / T 1 It can be 50%, 53.3%, 80%, or any value between two values, which is only given as an example and is not limited to any specific value. In this way, sufficient expansion gap can be ensured, and the electrode film can be prevented from being released, thereby ensuring the quality of the electrode film.

[0062] Specifically, after the first active material layer 2 is formed by coating the surface of the current collector 1 in different areas, an etching device such as a laser etcher is used to etch and scribe lines around the silicon material area. The etched electrode is rolled, and the compaction density of the rolling is controlled so that the size w of the groove structure 203 along the first direction is 1 Roll to the specified size. If H and T 1 is less than 50%, then the dimension w of the groove structure 203 along the first direction is 1 If the specified size is not reached, the etching area will be closed, the etching line will lose its meaning, and the process cost will be increased. 1 If the ratio is greater than 80%, it is easy to cause the adhesion between the slurry in the etched area and the current collector 1 to decrease, and insufficient peeling force will cause the electrode sheet to be peeled off, and ultimately cause the active material in this part to lose its function.

[0063] Specifically, as an optional embodiment of the present invention, in the first active material layer 2 , the first material region 201 includes a first activated carbon material, a first binder, a first conductive agent and a first solvent.

[0064] The second material region 202 includes a silicon material, a second activated carbon material, a second binder, a second conductive agent, and a second solvent.

[0065] The second active material layer 3 includes a third activated carbon material, a third binder, a third conductive agent, and a third solvent.

[0066] Furthermore, silicon materials include nano-silicon, silicon alloys, silicon-carbon composite materials and S i O x At least one of the materials.

[0067] The first activated carbon material, the second activated carbon material and the third activated carbon material all include at least one of natural graphite, artificial graphite, hard carbon, soft carbon and mesophase carbon microbeads.

[0068] The first binder, the second binder and the third binder all include one or more of polyvinylidene fluoride (PVDF), carboxymethyl cellulose (CMC), polyvinyl alcohol (PVA), polyacrylic acid (PAA), styrene butadiene rubber (SBR), and polyimide (PI).

[0069] The first conductive agent, the second conductive agent and the third conductive agent all include one or more of carbon black, Ketjen black, carbon nanotubes and graphene.

[0070] The first solvent, the second solvent and the third solvent all include N-Methylpyrrolidone (NMP) or water.

[0071] According to an embodiment of the present invention, on the other hand, a method for preparing a pole piece as in each of the above embodiments is also provided, comprising:

[0072] The surface of the current collector 1 is coated in different areas to form a first active material layer 2; wherein the first active material layer 2 includes a first material area 201 and a second material area 202, and the second material area 202 includes a silicon material;

[0073] Performing etching and scribing between the first material region 201 and the second material region 202 to form a groove structure 203;

[0074] The second active material layer 3 is formed by coating the surface of the first active material layer 2 .

[0075] Specifically, Figure 6 As shown, the coating die 4 includes an upper die 401, a lower die 402, and a gasket 403 disposed between the upper die 401 and the lower die 402. The upper die 401 is provided with a plurality of first feed channels 4011 and a plurality of second feed channels 4012, and the plurality of first feed channels 4011 and the plurality of second feed channels 4012 are arranged alternately in sequence according to a specified interval to control the size of the silicon-containing slurry coating area. Among them, the slurry pumped into the first feed channel 4011 is used to form the first material area 201, and the slurry pumped into the second feed channel 4012 is used to form the second material area 202. The lower die 402 is provided with a liquid storage tank 4021 to accommodate excess slurry. The current collector 1 is placed between the upper die 401 and the lower die 402, and different types of slurries are pumped into the multiple feed channels of the coating die 4 to achieve the effect of regional coating on the surface of the current collector 1.

[0076] like Figure 3 As shown, the first active material layer 2 is scribed by laser etching technology to form a groove structure 203 around the second material area 202, thereby providing expansion space for the silicon material. Since each second material area 202 corresponds to the coating position of the coating die 4, the silicon-containing slurry coating position can be found more accurately and quickly during laser etching and scribing, thereby improving etching efficiency.

[0077] Furthermore, a high-kinetic graphite layer is coated on the first active material layer 2 doped with silicon material to form the second active material layer 3, which can further suppress the expansion of the silicon material.

[0078] Preferably, in some embodiments of the present invention, before the step of coating the surface of the first active material layer 2, the method for preparing the pole piece further comprises:

[0079] The etched first active material layer 2 is rolled to make the size of the groove structure 203 along the first direction reach a preset size.

[0080] Specifically, during rolling, the compaction density is controlled so that the size of the groove structure 203 along the first direction reaches a preset size, and then the second active material layer 3 is coated, thereby effectively ensuring that the upper graphite particles do not occupy the etched groove area of ​​the lower layer.

[0081] Examples and Comparative Examples

[0082] Table 1 shows the process parameters of the negative electrode sheets of Examples 1-5 and Comparative Examples 1-2. The above-mentioned negative electrode sheets are stacked with the same ternary positive electrode sheets to form a soft-pack battery with a nominal capacity of 3Ah. Ah is the unit of battery capacity, and its full name is ampere-hour.

[0083] The capacity retention rate test method is as follows:

[0084] The battery was cycled at 25°C and 1C rate to test capacity retention.

[0085] Capacity retention rate = discharge capacity after specified number of cycles / discharge capacity in the first cycle.

[0086] The thickness expansion rate test method is as follows:

[0087] The soft-pack battery under the above cycle conditions is cycled for 500cls and 1000cls, and then charged to 100% SOC in the last cycle without discharging. The soft-pack battery is disassembled, and a negative electrode sheet in the middle of the stacking layers is selected (for example, if there are 9 layers of negative electrode sheets, the 5th layer of negative electrode sheets is selected). The thickness of the negative electrode sheet is measured with a micrometer, and then compared with the thickness of the negative electrode sheet charged to 100% SOC for the first time, and the thickness expansion rate is calculated. The test results of the capacity retention rate and the thickness expansion rate are shown in Table 1. Among them, cls refers to the cycle life span. SOC refers to the state of charge of the battery, that is, the ratio of the remaining power of the battery to its capacity in the fully charged state. SOC = 100% means that the battery is fully charged.

[0088] Table 1. Negative electrode sheet process parameters and physical and electrochemical performance test results

[0089]

[0090] According to Table 1, the electrode sheet in Comparative Example 1, which does not add silicon material and does not perform laser etching and scribing, has a much thicker electrode sheet than the negative electrode sheet containing silicon material at the same energy density. Due to the increase in thickness, the transmission path of lithium ions increases during the cycle, and the internal resistance of the battery increases. Therefore, after the battery has been cycled for the same number of times, its capacity retention rate is not as good as that of the embodiment.

[0091] The electrode in Comparative Example 2, in which silicon material is added and no laser etching and scribing is performed, is relatively thin at the same energy density. However, since no expansion cavity is reserved for the silicon material, the electrode expands greatly during the cycle process, which may lead to microstructural defects such as failure of part of the conductive network inside the electrode and demolding of part of the electrode from the current collector, which in turn leads to macrostructural defects such as increased overall thickness of the battery cell and reduced mechanical strength, ultimately resulting in a decrease in its capacity retention rate, which is lower than that of the embodiment.

[0092] From the above analysis, it can be seen that compared with the pole pieces in comparative examples 1-2, at the same energy density, the pole pieces provided by the embodiments of the present invention show smaller expansion in the thickness direction and better cycle performance.

[0093] According to an embodiment of the present invention, on the other hand, a battery is provided, including a battery cell, the battery cell including a positive electrode sheet, a negative electrode sheet, and a separator disposed between the positive electrode sheet and the negative electrode sheet, wherein the negative electrode sheet is configured as the electrode sheet in the above-mentioned embodiments. The derivation process of this beneficial effect is roughly similar to the derivation process of the beneficial effect of the above-mentioned electrode sheet, so it will not be repeated here.

[0094] According to an embodiment of the present invention, on the other hand, a vehicle is also provided, comprising a battery as in the above embodiment. Optionally, the vehicle is a new energy electric vehicle, a low-altitude aircraft, etc. The derivation process of the beneficial effect is roughly similar to the derivation process of the beneficial effect of the above battery, so it will not be repeated here.

[0095] In addition, as an optional implementation, the battery includes but is not limited to applications in new energy electric vehicles and low-altitude aircraft, and can also be applied to mobile terminals, power tools and other electrical equipment.

[0096] Although the embodiments of the present invention have been described in conjunction with the accompanying drawings, those skilled in the art may make various modifications and variations without departing from the spirit and scope of the present invention, and such modifications and variations are all within the scope defined by the appended claims.

Claims

1. A pole piece, characterized in that: The invention comprises a current collector (1) and a first active material layer (2) which are sequentially stacked along the thickness direction thereof, wherein the first active material layer (2) comprises a first material region (201) and a second material region (202) which are sequentially arranged along a first direction, wherein the second material region (202) comprises a silicon material, and a groove structure (203) is arranged between the first material region (201) and the second material region (202) so as to form a gap on a side of the first material region (201) and the second material region (202) which is away from the current collector (1).

2. The pole piece according to claim 1, characterized in that: The first material area (201) and the second material area (202) are configured as long strip areas extending along the second direction.

3. The pole piece according to claim 2, characterized in that: There are a plurality of the first material areas (201) and a plurality of the second material areas (202), and along the first direction, the plurality of the first material areas (201) and the plurality of the second material areas (202) are alternately distributed in sequence, and the groove structure (203) is provided between adjacent first material areas (201) and second material areas (202).

4. The pole piece according to claim 3, characterized in that: The sizes of the plurality of second material regions (202) along the first direction are all the same, and the distances between two adjacent second material regions (202) along the first direction are all the same.

5. The pole piece according to any one of claims 1 to 4, characterized in that: Also includes: The second active material layer (3) is stacked on a side of the first active material layer (2) away from the current collector (1).

6. The pole piece according to claim 5, characterized in that: The size of the groove structure (203) along the first direction is w1 μm, and the particle size of the active material in the second active material layer (3) is d μm; Wherein, w1<d, and / or, 1≤d≤10.

7. The pole piece according to claim 5, characterized in that: In one of the pole pieces, the mass of the silicon material in the first active material layer (2) is m1 kg, and the sum of the masses of the active materials in the first active material layer (2) and the second active material layer (3) is m2 kg, wherein 1%≤m1 / m2≤5%.

8. The pole piece according to claim 5, characterized in that: The thickness of the first active material layer (2) is T1 μm, the depth of the groove structure (203) is H μm, and the thickness of the second active material layer (3) is T2 μm; Among them, 60≤T1≤150; and / or, 50%≤H / T1≤80%; And / or, 40≤T2≤100.

9. A method for preparing a pole piece according to any one of claims 1 to 8, characterized in that: include: The surface of the current collector (1) is coated in different areas to form a first active material layer (2); wherein the first active material layer (2) comprises a first material area (201) and a second material area (202), and the second material area (202) comprises a silicon material; Performing etching and scribing between the first material region (201) and the second material region (202) to form a groove structure (203); A coating is performed on the surface of the first active material layer (2) to form a second active material layer (3).

10. The method for preparing a pole piece according to claim 9, characterized in that: Before the step of coating the surface of the first active material layer (2), the method further comprises: The first active material layer (2) after etching is rolled so that the size of the groove structure (203) along the first direction reaches a preset size.

11. A battery, characterized in that: The invention comprises a battery cell, wherein the battery cell comprises a positive electrode sheet, a negative electrode sheet and a separator arranged between the positive electrode sheet and the negative electrode sheet, wherein the negative electrode sheet is configured as the electrode sheet as claimed in any one of claims 1 to 8.

12. A carrier, characterized in that: Comprising the battery of claim 11.

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