Battery pole piece, manufacturing method thereof and battery

Abstract

The invention provides a battery pole piece, a manufacturing method thereof and a battery. The method comprises the following steps: providing a die-cut pole piece; the die-cut pole piece is cut, a wedge-shaped pole piece comprising a plurality of wedge-shaped parts connected in sequence is obtained, the width of the first end of each wedge-shaped part is smaller than that of the second end of the wedge-shaped part, the width of each wedge-shaped part is gradually increased from the first end to the second end in the first direction, and the width of each wedge-shaped part is larger than that of the first end; the first end of each wedge-shaped part located on the inner side is connected with the second end of one adjacent wedge-shaped part, and the second end of each wedge-shaped part located on the inner side is connected with the first end of the other adjacent wedge-shaped part. Due to the wedge-shaped structure of the pole piece, electrolyte adsorbed by the wedge-shaped pole piece is diffused from the wedge-shaped narrow end to the wide end, resistance can be effectively reduced, long-distance and high-speed spontaneous directional transportation capacity is achieved, diffusion of the electrolyte from the bottom or the top to the center area of the roll core can be accelerated, and the diffusion infiltration rate of the electrolyte is increased.

Description

Technical Field

[0001] The present invention relates to the technical field of battery manufacturing, and in particular to a battery pole piece, a manufacturing method thereof, and a battery. Background Art

[0002] Lithium-ion batteries are primarily composed of a positive electrode, a negative electrode, an electrolyte, and a separator. Li+ reversibly intercalates and deintercalates between the positive and negative electrodes through the separator, and the electrolyte serves as a carrier for the transfer of Li+. To ensure optimal battery performance, the electrolyte must completely infiltrate the positive, negative, and separator to form a Li+ conductive path. If this infiltration is insufficient, the ion transport path becomes longer, hindering the movement of lithium ions between the positive and negative electrodes. Electrodes not in contact with the electrolyte cannot participate in the battery's electrochemical reactions, and the battery's interfacial resistance increases, affecting the capacity, rate capability, and service life of the lithium-ion battery.

[0003] Currently, there are two mainstream methods for manufacturing battery cells: winding and lamination. The wound method suffers from relatively poor cell wettability. Firstly, due to structural limitations, the electrolyte can only penetrate from the bottom up. Secondly, to achieve a compact structure, the cell is usually compressed using hot pressing. Both methods affect electrode wettability, which can limit battery performance.

[0004] As the requirements for battery performance become higher and higher, thick electrodes have become the current mainstream trend. The increase in electrode thickness restricts the electrolyte's ability to penetrate the electrode and also affects the peeling force of the electrode. Summary of the Invention

[0005] Based on this, it is necessary to provide a battery electrode, a manufacturing method thereof, and a battery to address the above technical problems.

[0006] A method for manufacturing a battery pole piece, comprising:

[0007] Provide die-cut pole pieces;

[0008] The die-cut pole piece is cut to obtain a wedge-shaped pole piece comprising a plurality of wedge-shaped portions connected in sequence, wherein the width of the first end of each wedge-shaped portion is smaller than the width of the second end, and the width of each wedge-shaped portion gradually increases from the first end to the second end along the first direction, the first end of each wedge-shaped portion located on the inner side is connected to the second end of an adjacent wedge-shaped portion, and the second end of each wedge-shaped portion located on the inner side is connected to the first end of another adjacent wedge-shaped portion.

[0009] In one embodiment, each of the wedge-shaped portions is configured to be at least one of the following:

[0010] The included angle α of the first end of each wedge-shaped portion is ≤10°;

[0011] The width of the first end of each wedge-shaped portion is 0.1-2 mm;

[0012] The width of the second end of each wedge-shaped portion is 0.8-2.5 mm; and

[0013] A width ratio of the second end to the first end of each wedge-shaped portion is greater than or equal to 2.

[0014] In one embodiment, the step of cutting the die-cut pole piece to obtain a wedge-shaped pole piece comprising a plurality of wedge-shaped portions connected in sequence comprises:

[0015] The die-cut pole piece is laser cleaned to obtain a wedge-shaped pole piece comprising a plurality of wedge-shaped portions connected in sequence, and the surface of the wedge-shaped pole piece is roughened.

[0016] In one embodiment, the laser during the laser cleaning is set to at least one of the following conditions:

[0017] The adjustment range of the laser frequency is: 10KHz~100MHz;

[0018] The adjustment range of the laser pulse width is: 10ps~100fs; and

[0019] The thickness of the laser cleaning of the die-cut pole piece is 1-200 μm.

[0020] In one embodiment, the step of providing the die-cut pole piece includes:

[0021] providing an active substance slurry;

[0022] coating the active material slurry on the surface of the current collector to obtain a coated electrode;

[0023] The coated electrode piece is rolled, die-cut, slit and cut into pieces to obtain the die-cut electrode piece.

[0024] In one embodiment, the active material slurry and the current collector are configured as at least one of the following:

[0025] The active material slurry comprises positive electrode powder or negative electrode powder, conductive carbon, a binder and a dispersant, wherein the positive electrode powder or negative electrode powder ratio is 94%-98%, the conductive carbon ratio is 0.3%-1.5%, the binder ratio is 1%-3%, and the dispersant ratio is 0.2%-1.5%; and

[0026] The thickness of the current collector is 3-15 μm.

[0027] In one embodiment, the components in the active material slurry are configured to be at least one of the following:

[0028] The positive electrode powder includes one or more of lithium cobalt oxide, lithium nickel oxide, lithium manganese oxide, lithium nickel manganese oxide, lithium nickel cobalt manganese oxide, lithium nickel cobalt aluminum oxide, and lithium phosphate with an olivine structure; the negative electrode powder includes one or more of graphite, silicon carbon, and lithium titanate;

[0029] The conductive carbon is a linear conductive carbon with high oil absorption value or a block conductive carbon with high oil absorption value;

[0030] When the conductive carbon is a linear conductive carbon with high oil absorption value, wherein the conductive carbon is a linear conductive carbon with high oil absorption value and includes one or more of carbon nanotubes and carbon fibers, and the oil absorption value of the linear conductive carbon with high oil absorption value satisfies: 180mL / 100g≤OAN≤400mL / 100g;

[0031] When the conductive carbon is a bulk conductive carbon with high oil absorption value, the bulk conductive carbon with high oil absorption value is one or more of conductive carbon black, acetylene black, Ketjen black, graphene, etc.; the oil absorption value OAN of the bulk conductive carbon black with high oil absorption value satisfies: 250mL / 100g≤OAN≤400mL / 100g;

[0032] When the active material slurry is a negative electrode active material slurry, the viscosity of the negative electrode active material slurry is in the range of 4000-8000 mPa·s.

[0033] In one embodiment, when the electrode is a positive electrode, in the steps of rolling, die-cutting, slitting, and cutting the coated electrode, the compaction density of the rolling is 2.0-4.5 g / cm 3 When the electrode is a negative electrode, the rolling, die-cutting, slitting and cutting steps of the coated electrode are performed, and the compaction density of the rolling is 1.2-1.8 g / cm 3 .

[0034] A battery electrode comprises: a plurality of wedge-shaped portions connected in sequence, wherein the width of the first end of each wedge-shaped portion is smaller than the width of the second end, and the width of each wedge-shaped portion gradually increases from the first end to the second end along a first direction, the first end of each wedge-shaped portion located on the inner side is connected to the second end of an adjacent wedge-shaped portion, and the second end of each wedge-shaped portion located on the inner side is connected to the first end of another adjacent wedge-shaped portion.

[0035] A battery comprises the battery electrode described in the above embodiment.

[0036] The above-mentioned battery electrode and its manufacturing method, battery, and the wedge-shaped structure of the electrode enable the electrolyte adsorbed by the wedge-shaped electrode to diffuse along the narrow end (first end) of the wedge to the wide end (second section), which can effectively reduce resistance, have long-distance, high-speed spontaneous directional transportation capabilities, and can accelerate the diffusion of electrolyte from the bottom or top to the center area of the core, thereby improving the diffusion and infiltration rate of the electrolyte. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 Schematic diagram of a process for manufacturing a button battery in one embodiment;

[0038] Figure 2 Schematic diagram of the structure of a wedge-shaped pole piece in one embodiment;

[0039] Figure 3 FIG1 is a schematic structural diagram of a battery equipped with a wedge-shaped pole piece in one embodiment;

[0040] Figure 4A This is the wetting interface of a conventional electrode in one direction after the electrolyte is injected for 1 hour;

[0041] Figure 4B This is the wetting interface of the conventional electrode in the other direction after the electrolyte is injected for 1 hour;

[0042] Figure 5A The wetting interface of a wedge-shaped electrode in one embodiment after the electrolyte is injected for 1 hour;

[0043] Figure 5B This is the wetting interface of the wedge-shaped electrode in one embodiment in another direction after the electrolyte is injected for 1 hour.

[0044] Description of reference numerals:

[0045] 10. Pole piece; 100. Wedge-shaped portion; 110. First end; 120. Second end; 20. Battery; DETAILED DESCRIPTION

[0046] In order to make the purpose, technical solutions and advantages of this application more clear, the following further describes this application in detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain this application and are not intended to limit this application.

[0047] Example 1

[0048] In this embodiment, Figure 1 As shown, a method for manufacturing a battery electrode is provided, which includes:

[0049] Step 110: Provide a die-cut electrode.

[0050] Step 120: Cut the die-cut pole piece to obtain a wedge-shaped pole piece comprising a plurality of wedge-shaped portions connected in sequence, wherein the width of the first end of each wedge-shaped portion is smaller than the width of the second end, and the width of each wedge-shaped portion gradually increases from the first end to the second end along the first direction, the first end of each wedge-shaped portion located on the inner side is connected to the second end of an adjacent wedge-shaped portion, and the second end of each wedge-shaped portion located on the inner side is connected to the first end of another adjacent wedge-shaped portion.

[0051] In this embodiment, Figure 2 and Figure 3 As shown, the wedge-shaped portions 100 of the wedge-shaped pole piece 10 are connected in series, with the tips of the wedges facing the same direction. The width of the first end 110 of each wedge-shaped portion 100 is smaller than the width of the second end 120, and the width of each wedge-shaped portion 100 gradually increases from the first end 110 to the second end 120 along the first direction. The first end 110 of each wedge-shaped portion 100 located on the inside is connected to the second end 120 of an adjacent wedge-shaped portion 100, and the second end 120 of each wedge-shaped portion 100 located on the inside is connected to the first end 110 of another adjacent wedge-shaped portion 100. The wedge-shaped portions 100 located on the inside in this embodiment refer to the other wedge-shaped portions 100 except those located at the two ends of the wedge-shaped pole piece 10. The wedge-shaped pole piece 10 can be a positive pole piece 10 or a negative pole piece 10. In other words, both the positive pole piece 10 and the negative pole piece 10 of the battery 20 can adopt this structure.

[0052] like Figure 3 As shown, when the wedge-shaped electrode piece 10 is installed in the battery 20, the positive electrode piece 10, the separator, and the negative electrode piece 10 are stacked in order, and the first end 110 of each wedge-shaped portion 100 of the wedge-shaped electrode piece 10 is wound toward the bottom of the battery 20 to form a battery cell 20. This structure is designed based on the bionic design of a water bird's beak. In this way, the electrolyte adsorbed by the wedge-shaped electrode piece 10 diffuses from the narrow end of the wedge (first end 110) to the wide end (second section), which can effectively reduce resistance and provide long-distance, high-speed spontaneous directional transport capabilities. It can accelerate the diffusion of electrolyte from the bottom or top to the center area of the winding core, and improve the diffusion and infiltration rate of the electrolyte.

[0053] In one embodiment, the angle α of the first end of each of the wedge-shaped portions is ≤10°. It is worth mentioning that if the angle of the first end of the wedge-shaped portion is too small, the electrolyte cannot fully diffuse to both sides, and if the angle of the first end of the wedge-shaped portion is too large, the electrolyte diffuses to both sides, and it is impossible to fully guide the electrolyte to diffuse and infiltrate from the first end to the second end of the wedge-shaped portion. Therefore, in this embodiment, the angle α of the first end of each of the wedge-shaped portions is ≤10°, which can effectively reduce resistance and enable the electrolyte to diffuse to both sides, accelerating the diffusion of the electrolyte from the bottom or top to the center area of the core at the same time. In addition, too small an angle α may also lead to stress concentration, but the wide and narrow ends of adjacent wedge-shaped portions are alternately connected to form a "chain interlocking" structure, which can effectively disperse local stress and avoid tip fracture.

[0054] In one embodiment, the width w1 of the first end of each wedge-shaped portion is 0.1-2 mm. It should be understood that if the width of the first end of each wedge-shaped portion is too large, it will create excessive resistance to the diffusion of the electrolyte. If the width of the first end of each wedge-shaped portion is too small, the electrolyte guidance efficiency will be reduced, and it will be impossible to guide excessive amounts of electrolyte. Therefore, in this embodiment, the width w1 of the first end of each wedge-shaped portion is 0.1-2 mm, which can effectively reduce the guidance resistance and improve the guidance efficiency, thereby enabling the electrolyte to diffuse quickly and efficiently. Furthermore, the width w1 of the first end of the wedge-shaped portion is 0.1-2 mm, which can also effectively improve the mechanical strength of the first end and prevent breakage.

[0055] In one embodiment, the width of the second end of each of the wedge-shaped portions is 0.8-2.5 mm. It should be understood that if the width of the second end of each of the wedge-shaped portions is too large, the electrolyte will not be able to smoothly transition between the second end of the wedge-shaped portion and the first end of the adjacent wedge-shaped portion, and if the width of the second end of each of the wedge-shaped portions is too small, the electrolyte will not be able to fully diffuse to both sides. Therefore, in this embodiment, the width of the second end of each of the wedge-shaped portions is 0.8-2.5 mm, which can not only make the electrolyte smoothly transition between the second end of the wedge-shaped portion and the first end of the adjacent wedge-shaped portion, but also improve the diffusion efficiency and speed between adjacent wedge-shaped portions, so that the electrolyte can diffuse to both sides, and speed up the diffusion of the electrolyte to the center area of the core. In addition, the large contact area of the second end of the wedge-shaped portion can enhance the bonding force between the electrode and the current collector, and compensate for the risk of interface peeling that may be caused by the extremely small width of the narrow end.

[0056] In one embodiment, the ratio of the width of the second end to the first end of each wedge-shaped portion is greater than or equal to 2. In this embodiment, the ratio of the width w2 of the second end of each wedge-shaped portion to the width w1 of the first end is greater than or equal to 2. It should be understood that the width ratio of the wide end to the narrow end of the wedge-shaped portion is related to the diffusion and diffusion efficiency of the electrolyte. If the ratio of the width w2 of the second end of the wedge-shaped portion to the width w1 of the first end is too small, the electrolyte cannot fully diffuse to the sides. If the ratio of the width w2 of the second end of the wedge-shaped portion to the width w1 of the first end is too large, the electrolyte cannot be fully guided from the first end to the second end of the wedge-shaped portion, resulting in greater resistance. Therefore, in this embodiment, the ratio of the width w2 of the second end of each wedge-shaped portion to the width w1 of the first end is greater than or equal to 2. This allows the electrolyte to fully diffuse to the sides and toward the center of the battery cell. On the other hand, it can further reduce resistance, making the diffusion of the electrolyte smoother and improving the diffusion speed and efficiency of the electrolyte.

[0057] In one embodiment, the step of cutting the die-cut pole piece to obtain a wedge-shaped pole piece comprising a plurality of wedge-shaped portions connected in sequence comprises:

[0058] The die-cut pole piece is laser cleaned to obtain a wedge-shaped pole piece comprising a plurality of wedge-shaped portions connected in sequence, and the surface of the wedge-shaped pole piece is roughened.

[0059] In this embodiment, laser cleaning not only cuts the electrode into a wedge shape, but also roughens the surface of the wedge-shaped electrode. Specifically, after laser cleaning, the surface roughness of the electrode increases, increasing the contact area with the electrolyte and facilitating adsorption and infiltration of the electrode.

[0060] In one embodiment, the frequency of the laser is adjustable in the range of 10 kHz to 100 MHz. In one embodiment, the pulse width of the laser is adjustable in the range of 10 ps to 100 fs. In this embodiment, a laser with an adjustable range of 10 kHz to 100 MHz and a pulse width adjustable range of 10 ps to 100 fs is used to efficiently and accurately clean and cut the electrode.

[0061] In one embodiment, the thickness of the laser cleaning of the die-cut pole piece is 1-200um. It should be understood that if the thickness of the laser cleaning is too large, the thickness of the pole piece will be smaller.

[0062] In this embodiment, the thickness of the laser cleaning of the surface of the electrode is 1-200 μm, and the cleaned area meets the NP value requirement of the battery cell.

[0063] In one embodiment, the step of providing a die-cut electrode sheet includes: providing an active material slurry; coating the active material slurry on the surface of the current collector to obtain a coated electrode sheet; and rolling, die-cutting, slitting, and cutting the coated electrode sheet to obtain the die-cut electrode sheet.

[0064] This embodiment provides steps for preparing a pole piece. Specifically, the active material slurry can be a positive electrode slurry or a negative electrode slurry, and the current collector serves as the pole piece substrate, which can also be a porous aluminum or copper sheet. After the active material slurry is coated on the current collector surface, the active material slurry is dried to form an active material layer on the current collector surface, resulting in a coated pole piece. The pole piece is then sequentially rolled, die-cut, slit, and cut into pieces to obtain individual pole pieces.

[0065] In this embodiment, the current collector includes a porous aluminum current collector or a copper current collector.

[0066] In one embodiment, the active material slurry includes positive electrode powder or negative electrode powder, conductive carbon, a binder and a dispersant, wherein the proportion of the positive electrode powder or negative electrode powder is 94%-98%, the proportion of the conductive carbon is 0.3%-1.5%, the proportion of the binder is 1%-3%, and the proportion of the dispersant is 0.2%-1.5%.

[0067] In this embodiment, when preparing the positive electrode active material slurry, the positive electrode powder is mixed evenly with the conductive carbon, the binder, and the dispersant in the above-mentioned proportions, and a solvent is added to obtain the positive electrode active material slurry; when preparing the positive electrode active material slurry, the negative electrode powder is mixed evenly with the conductive carbon, the binder, and the dispersant in the above-mentioned proportions, and a solvent is added to obtain the negative electrode active material slurry.

[0068] In one embodiment, the thickness of the current collector is 3-15 μm. It should be understood that if the thickness of the current collector is too large, it will affect the electrode's ability to wet the electrolyte, and if the thickness of the current collector is too small, it will affect the mechanical strength of the electrode, resulting in a break between the first end of the wedge-shaped portion and the second end of the adjacent wedge-shaped portion. In this embodiment, the current collector serves as a support, and its thickness is 3-15 μm, which can effectively avoid the connection between the narrowest and widest parts of the wedge, avoid breakage between adjacent wedge-shaped portions, and effectively ensure the wettability of the electrolyte.

[0069] In one embodiment, the positive electrode powder includes one or more of lithium cobalt oxide, lithium nickel oxide, lithium manganese oxide, lithium nickel manganese oxide, lithium nickel cobalt manganese oxide, lithium nickel cobalt aluminum oxide, and olivine-structured lithium-containing phosphate; the negative electrode powder includes one or more of graphite, silicon carbon, and lithium titanate.

[0070] In this embodiment, the positive electrode powder material includes one or more combinations of lithium cobalt oxide, lithium nickel oxide, lithium manganese oxide, lithium nickel manganese oxide, lithium nickel cobalt manganese oxide, lithium nickel cobalt aluminum oxide, and olivine-structured lithium-containing phosphates; the negative electrode powder includes one or more combinations of graphite, silicon carbon, and lithium titanate.

[0071] In one embodiment, the conductive carbon is a linear conductive carbon with high oil absorption value or a block conductive carbon with high oil absorption value;

[0072] When the conductive carbon is a linear conductive carbon with high oil absorption value, wherein the conductive carbon is a linear conductive carbon with high oil absorption value and includes one or more of carbon nanotubes and carbon fibers, and the oil absorption value of the linear conductive carbon with high oil absorption value satisfies: 180mL / 100g≤OAN≤400mL / 100g;

[0073] When the conductive carbon is a block conductive carbon with high oil absorption value, the block conductive carbon with high oil absorption value is one or more of conductive carbon black, acetylene black, Ketjen black, graphene, etc.; the oil absorption value OAN of the block conductive carbon black with high oil absorption value satisfies: 250mL / 100g≤OAN≤400mL / 100g.

[0074] In this embodiment, the linear conductive carbon with high oil absorption value can form a local high-density conductive network at the narrow end (first end) of the wedge-shaped portion, thereby avoiding the problem of excessive current density at the narrow end due to its small width.

[0075] In this embodiment, the high oil absorption value block conductive carbon can form a surface contact conductive network at the wide end (second end) of the wedge-shaped portion, thereby improving the overall conductivity; and its high oil absorption value OAN 250-400mL / 100g can adsorb electrolyte, combined with the directional diffusion ability of the wedge-shaped structure, accelerates the longitudinal penetration of the electrolyte along the electrode.

[0076] In one embodiment, when the active material slurry is a negative electrode active material slurry, the viscosity of the negative electrode active material slurry is in the range of 4000-8000 mPa·s.

[0077] In this embodiment, the negative electrode powder is uniformly mixed with the conductive carbon, the binder, and the dispersant in the above proportions, and a solvent is added to prepare a negative electrode active material slurry having a viscosity in the range of 4000-8000 mPa.s. After filtering through a 150-mesh sieve, the filtered negative electrode active material slurry is coated on the current collector.

[0078] In this embodiment, the viscosity of the negative electrode active material slurry is in the range of 4000-8000 mPa·s, which can effectively prevent the accumulation of the negative electrode active material slurry during the coating process and avoid uneven coating.

[0079] In this embodiment, the conductive agent used in the electrode sheet is primarily linear conductive carbon and flake conductive carbon with high oil absorption, which can form long-range and short-range conductive networks. This not only enhances electron conduction but also facilitates electrolyte infiltration, retaining more electrolyte and increasing ionic conductivity. This is beneficial to the performance of the battery cell and meets the requirements of long cycle and high power.

[0080] In one embodiment, when the electrode is a positive electrode, in the steps of rolling, die-cutting, slitting, and cutting the coated electrode, the compaction density of the rolling is 2.0-4.5 g / cm 3 When the electrode is a negative electrode, the rolling, die-cutting, slitting and cutting steps of the coated electrode are performed, and the compaction density of the rolling is 1.2-1.8 g / cm 3 .

[0081] In this embodiment, the positive electrode sheet adopts a high compaction density (2.0-4.5g / cm 3 ), high density easily leads to difficulty in electrolyte infiltration, but the wide end of the wedge-shaped part can provide a larger pore channel. Combined with the laser roughening surface, a multi-scale pore structure can be formed to accelerate the diffusion of the electrolyte along the width direction.

[0082] In this embodiment, the negative electrode sheet adopts a low compaction density (1.2-1.8g / cm 3 ), with low density to accommodate the expansion characteristics of the silicon-carbon anode, but without compromising the electrode structure. Furthermore, adjacent wedge-shaped sections are connected alternately by wide and narrow ends, forming a "wave-like" buffer structure that effectively absorbs the stress of volume changes during charge and discharge of the anode while maintaining the overall integrity of the electrode.

[0083] Example 2

[0084] In this embodiment, Figure 2 As shown, a battery electrode 10 is provided, comprising: a plurality of wedge-shaped portions 100 connected in sequence, wherein the width of the first end 110 of each wedge-shaped portion 100 is smaller than the width of the second end 120, and the width of each wedge-shaped portion 100 gradually increases from the first end 110 to the second end 120 along a first direction, the first end 110 of each wedge-shaped portion 100 located on the inner side is connected to the second end 120 of an adjacent wedge-shaped portion 100, and the second end 120 of each wedge-shaped portion 100 located on the inner side is connected to the first end 110 of another adjacent wedge-shaped portion 100.

[0085] In this embodiment, the battery electrode is manufactured using the manufacturing method of the battery electrode in any of the above embodiments.

[0086] Example 3

[0087] In this embodiment, a battery is provided, comprising the battery electrode described in any of the above embodiments.

[0088] Example 4

[0089] In this embodiment, the process of manufacturing battery electrodes and batteries is as follows:

[0090] (1) The positive electrode or negative electrode active material is mixed uniformly with conductive carbon or conductive liquid, a binder, a dispersant, and a solvent in a certain proportion to obtain a positive electrode or negative electrode slurry;

[0091] (2) coating the positive or negative electrode slurry obtained in step (1) on a porous aluminum or copper current collector, and drying the coated electrode to obtain a coated electrode sheet, which is then rolled, die-cut, slit, and cut into pieces;

[0092] (3) Laser cleaning the die-cut electrode, setting the clearing program, and cleaning the electrode into a series wedge shape parallel to the width direction of the core;

[0093] In one embodiment, in step (1), the proportion of positive electrode or negative electrode powder is 94%-98%, the proportion of conductive carbon is 0.3%-1.5%, the proportion of binder is 1%-3%, and the proportion of dispersant is 0.2%-1.5%.

[0094] In one embodiment, the positive electrode powder material in step (1) includes one or more combinations of lithium cobalt oxide, lithium nickel oxide, lithium manganese oxide, lithium nickel manganese oxide, lithium nickel cobalt manganese oxide, lithium nickel cobalt aluminum oxide, and lithium phosphate containing an olivine structure; the negative electrode powder includes one or more combinations of graphite, silicon carbon, and lithium titanate;

[0095] In one embodiment, in step (1), the linear conductive carbon with high oil absorption value is one or more combinations of carbon nanotubes and carbon fibers; the oil absorption value of the linear conductive carbon with high oil absorption value satisfies: 180mL / 100g≤OAN≤400mL / 100g; the block conductive carbon with high oil absorption value is one or more combinations of conductive carbon black, acetylene black, Ketjen black, graphene, etc.; the oil absorption value OAN of the flake conductive carbon black with high oil absorption value satisfies: 250mL / 100g≤OAN≤400mL / 100g;

[0096] In one embodiment, in step (1), the negative electrode slurry prepared has a viscosity in the range of 4000-8000 mPa.s, is filtered through a 150-mesh sieve, and then coated on the current collector.

[0097] In one embodiment, in step (2), the thickness of the current collector is 3-15 μm.

[0098] In one embodiment, the electrode prepared in step (2) is coated and baked at a temperature of 80° C. to 120° C., and the coating surface density is 100 to 200 g / m 2 .

[0099] In one embodiment, in step (2), the roller compaction density of the electrode pieces is 2.0-4.5 g / cm3 for the positive electrode and 1.2-1.8 g / cm3 for the negative electrode.

[0100] In one embodiment, the frequency of the laser used for laser cleaning in step (3) is adjusted in the range of 10 kHz to 100 MHz; the pulse width of the laser is adjusted in the range of 10 ps to 100 fs.

[0101] In one embodiment, the thickness of the laser cleaning in step (3) is 1-200 μm, and the cleaned area meets the requirements of the battery cell NP value;

[0102] In one embodiment, the shape of the cleaning in step (3) is similar to the structure of a water bird's beak, which is a series wedge structure, such as Figure 1 As shown, the direction is parallel to the width direction of the pole piece; the wedge angle α of the wedge structure is ≤10°, the width w1 of the narrow end of the connection is 0.1-2mm, the width w2 of the wide end of the connection is 0.8-2.5mm, and w2 / w1 ≥0.5; the structure satisfies long-distance, high-speed spontaneous directional transportation;

[0103] In one embodiment, a lithium battery is provided. The lithium battery is prepared using the wedge-shaped pole piece described in any of the above embodiments.

[0104] In one embodiment, preparing a lithium battery using the wedge-shaped pole piece in the above embodiment includes the following steps:

[0105] A. Stack the positive electrode sheet, separator, and negative electrode sheet in order so that the cleaning position is in the middle of the large surface of the winding core. Figure 3 As shown, a bare cell is obtained after winding;

[0106] B. Place the bare cell obtained in step A in an outer packaging shell, inject electrolyte after drying, and perform post-processing to obtain a lithium battery.

[0107] In one embodiment, in step B, the post-processing is vacuum packaging, standing, chemical formation, and volume separation.

[0108] Performance parameter comparison:

[0109] In this section, the electrolyte infiltration rates of conventional pole pieces and the cleaned wedge-shaped pole pieces manufactured by the manufacturing method of the above embodiment are compared. The comparison results are shown in Table 1.

[0110] Table 1 Comparison of electrolyte wetting rates of conventional electrodes and cleaned wedge-shaped electrodes

[0111]

[0112] As can be seen from the above table, the electrolyte infiltration rate of the cleaned wedge-shaped electrode is greatly improved compared with the traditional conventional electrode, which is equivalent to being doubled.

[0113] Figure 4A and Figure 4B This is a schematic diagram of the wetting interface of a conventional electrode after 1 hour of electrolyte injection. Figure 5A and Figure 5B A schematic diagram of the wetting interface in another direction of a wedge-shaped electrode manufactured by the method of any of the above embodiments after the electrolyte is injected for 1 hour. By comparison, it can be seen that Figure 4A and Figure 4B The unwetted area is larger, while the wedge-shaped pole piece manufactured by the method in the embodiment of the present application does not have an unwetted area, and the wetting effect is better.

[0114] The technical features of the above embodiments can be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0115] The above-described embodiments merely represent several implementation methods of the present application. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that a person skilled in the art could make various modifications and improvements without departing from the spirit of the present application, all of which fall within the scope of protection of the present application. Therefore, the scope of protection of the present patent application shall be determined by the appended claims.

Claims

1. A method for manufacturing a battery pole piece, characterized in that: include: Provide die-cut pole pieces; The die-cut pole piece is cut to obtain a wedge-shaped pole piece comprising a plurality of wedge-shaped portions connected in sequence, wherein the width of the first end of each wedge-shaped portion is smaller than the width of the second end, and the width of each wedge-shaped portion gradually increases from the first end to the second end along the first direction, the first end of each wedge-shaped portion located on the inner side is connected to the second end of an adjacent wedge-shaped portion, and the second end of each wedge-shaped portion located on the inner side is connected to the first end of another adjacent wedge-shaped portion.

2. The method according to claim 1, characterized in that Each of the wedge-shaped portions is configured as at least one of the following: The included angle α of the first end of each wedge-shaped portion is ≤10°; The width of the first end of each wedge-shaped portion is 0.1-2 mm; The width of the second end of each wedge-shaped portion is 0.8-2.5 mm; and A width ratio of the second end to the first end of each wedge-shaped portion is greater than or equal to 2.

3. The method according to claim 1, characterized in that The step of cutting the die-cut pole piece to obtain a wedge-shaped pole piece comprising a plurality of wedge-shaped portions connected in sequence comprises: The die-cut pole piece is laser cleaned to obtain a wedge-shaped pole piece comprising a plurality of wedge-shaped portions connected in sequence, and the surface of the wedge-shaped pole piece is roughened.

4. The method according to claim 3, characterized in that The laser cleaning is configured to be at least one of the following: The adjustment range of the laser frequency is: 10KHz~100MHz; The adjustment range of the laser pulse width is: 10ps~100fs; and The thickness of the laser cleaning of the die-cut pole piece is 1-200 μm.

5. The method according to claim 1, wherein The step of providing the die-cut pole piece comprises: providing an active substance slurry; coating the active material slurry on the surface of the current collector to obtain a coated electrode; The coated electrode piece is rolled, die-cut, slit and cut into pieces to obtain the die-cut electrode piece.

6. The method according to claim 5, characterized in that The active material slurry and the current collector are configured as at least one of the following: The active material slurry comprises positive electrode powder or negative electrode powder, conductive carbon, a binder and a dispersant, wherein the positive electrode powder or negative electrode powder ratio is 94%-98%, the conductive carbon ratio is 0.3%-1.5%, the binder ratio is 1%-3%, and the dispersant ratio is 0.2%-1.5%; and The thickness of the current collector is 3-15 μm.

7. The method according to claim 6, characterized in that The components in the active material slurry are configured to be at least one of the following: The positive electrode powder includes one or more of lithium cobalt oxide, lithium nickel oxide, lithium manganese oxide, lithium nickel manganese oxide, lithium nickel cobalt manganese oxide, lithium nickel cobalt aluminum oxide, and lithium phosphate with an olivine structure; the negative electrode powder includes one or more of graphite, silicon carbon, and lithium titanate; The conductive carbon is a linear conductive carbon with high oil absorption value or a block conductive carbon with high oil absorption value; When the conductive carbon is a linear conductive carbon with high oil absorption value, wherein the conductive carbon is a linear conductive carbon with high oil absorption value and includes one or more of carbon nanotubes and carbon fibers, and the oil absorption value of the linear conductive carbon with high oil absorption value satisfies: 180mL / 100g≤OAN≤400mL / 100g; When the conductive carbon is a bulk conductive carbon with high oil absorption value, the bulk conductive carbon with high oil absorption value is one or more of conductive carbon black, acetylene black, Ketjen black, graphene, etc.; the oil absorption value OAN of the bulk conductive carbon black with high oil absorption value satisfies: 250mL / 100g≤OAN≤400mL / 100g; When the active material slurry is a negative electrode active material slurry, the viscosity of the negative electrode active material slurry is in the range of 4000-8000 mPa·s.

8. The method according to claim 5, characterized in that When the electrode is a positive electrode, in the steps of rolling, die-cutting, slitting and cutting the coated electrode, the compaction density of the rolling is 2.0-4.5 g / cm 3 When the electrode is a negative electrode, the rolling, die-cutting, slitting and cutting steps of the coated electrode are performed, and the compaction density of the rolling is 1.2-1.8 g / cm 3 .

9. A battery pole piece, characterized in that: The battery electrode manufacturing method according to any one of claims 1 to 8 is adopted, comprising: a plurality of wedge-shaped portions connected in sequence, the width of the first end of each of the wedge-shaped portions being smaller than the width of the second end, and the width of each of the wedge-shaped portions gradually increasing from the first end to the second end along the first direction, the first end of each of the wedge-shaped portions located on the inner side being connected to the second end of an adjacent wedge-shaped portion, and the second end of each of the wedge-shaped portions located on the inner side being connected to the first end of another adjacent wedge-shaped portion.

10. A battery, characterized in that: Including the battery electrode according to claim 9.

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