A high-rate performance lithium-ion battery and a method for manufacturing the thick electrode sheet thereon.

Abstract

This invention discloses a high-rate performance lithium-ion battery and a method for manufacturing the thick electrode sheet thereon. The method for manufacturing the thick electrode sheet includes the following steps: S100, preparing the powder to be laid, thoroughly mixing electrode active material particles with a conductive agent to obtain the powder to be laid in binder jet printing additive manufacturing; S200, powder laying and printing, forming a predetermined channel pattern during the layer-by-layer powder laying and printing process; S300, performing the next cycle of layer-by-layer powder laying and printing; S400, repeating steps S200 and S300 until the thick electrode sheet or the manufacturing of the thick electrode sheet is completed. The high-rate performance lithium-ion battery and the method for manufacturing the thick electrode sheet thereon provided by this invention have excellent pattern control and shaping capabilities, and can realize the efficient large-scale production of battery thick electrode sheets with channel patterns. Furthermore, the manufacturing method of this invention can effectively improve the energy density, rate performance, and service life of lithium batteries.

Description

Technical Field

[0001] This invention relates to lithium-ion batteries, and more particularly to a thick electrode configuration and its manufacturing method, as well as a lithium-ion battery with high rate performance using the thick electrode. Background Technology

[0002] In lithium-ion batteries, increasing the thickness and loading of the positive and negative electrodes can effectively improve the battery's energy density. However, with increased electrode thickness, the rate performance (or kinetic performance) of the battery weakens because lithium ions need to diffuse more within the electrode than in the electrolyte with high ionic conductivity. Simultaneously, thicker electrodes are also detrimental to electrolyte wetting. Appropriately introducing channels into the battery electrodes can effectively improve the rate performance and wettability of the electrodes, such as... Figure 1 As shown, the introduction of this structure often has a serious impact on production efficiency, or causes loss or deterioration in product quality and performance. Therefore, there is currently no truly effective solution to the above problems.

[0003] Chinese invention patent application CN109768223A discloses a method for preparing a wound lithium-ion battery negative electrode sheet. This method uses laser etching to carve grooves 10 in the width direction of the negative electrode sheet onto the surface of the active material layer. Figure 1 The schematic diagram is shown. Chinese invention patent application CN114203970A discloses an electrode sheet for improving the wettability of lithium battery electrolyte and its preparation method. This technical solution uses a needle to carve grooves in the electrode sheet. However, both technical solutions have significant drawbacks: laser carving requires point-by-point scanning and cutting, which is time-consuming due to limitations in the light power density of the laser applied to the processing material. Furthermore, it cannot carve deeply, and the carving process causes chemical changes on the electrode surface, producing toxic and harmful gases that pollute the environment. Needle carving, on the other hand, produces carving debris or burrs, degrading the battery's cycle performance. In addition, the equipment used is expensive, requires high operational precision, and is not easily commercialized.

[0004] In conclusion, a new method that is flexible, efficient, and suitable for large-scale production is needed. Summary of the Invention

[0005] To overcome the aforementioned deficiencies of the prior art, this application provides a method for manufacturing a thick electrode sheet, comprising the following steps:

[0006] S100 Preparation of the spreading powder: The electrode active material particles are thoroughly mixed with the conductive agent to obtain the spreading powder required for binder jet printing additive manufacturing.

[0007] S200, Powder Spreading and Printing: At the powder spreading and printing station, the powder is spread and printed layer by layer onto the battery current collector, and a predetermined channel pattern is formed during the layer-by-layer powder spreading and printing process.

[0008] S300: The battery current collector that has been coated and printed with powder is sent out from the powder coating and printing station, and at the same time, the battery current collector to be coated and printed with powder is sent to the powder coating and printing station for the next cycle of layer-by-layer powder coating and printing.

[0009] S400. Repeat steps S200 and S300 above until the manufacturing of the thick electrode positive sheet or the thick electrode negative sheet is completed.

[0010] The present invention may also employ the following optional / preferred solutions:

[0011] The layer-by-layer powder spreading and printing in step S200 are achieved through adhesive spraying technology.

[0012] In step S300, the battery current collector is transported by connecting a battery current collector reel to a conveyor belt, and a blank area for cutting is left between two adjacent powder-spreading and printing of the battery current collector.

[0013] It also includes a heat curing molding step, that is, after step S200 or step S300, the thick electrode sheet after powder printing and forming of channel pattern is subjected to heat curing molding treatment.

[0014] In step S100, the electrode active material particles are positive electrode active material particles or negative electrode active material particles; when the electrode active material particles are positive electrode active material particles, the resulting spreading powder is positive electrode spreading powder, and when the electrode active material particles are negative electrode active material particles, the resulting spreading powder is negative electrode spreading powder.

[0015] The battery current collector is copper foil or aluminum foil; the positive electrode active material particles are at least one of lithium cobalt oxide, lithium iron phosphate, lithium manganese oxide, and ternary positive electrode material particles; the negative electrode active material particles are at least one of silicon, silicon carbide, and lithium titanate; and the conductive agent is conductive carbon black.

[0016] The temperature for heating and curing is 100-120℃.

[0017] The predetermined channel pattern has two or more layers, and the predetermined channel patterns of adjacent layers are the same or different.

[0018] The predetermined channel patterns of two or more layers are at least partially interconnected.

[0019] The present invention also provides a method for manufacturing a high-rate lithium-ion battery, comprising a positive electrode and a negative electrode, wherein the positive electrode and / or the negative electrode are made of a thick electrode sheet, and the thick electrode sheet is prepared by the manufacturing method described in any of the above.

[0020] The one or more technical solutions provided in this application have at least the following advantages compared with the prior art:

[0021] The high-rate performance lithium-ion battery and its manufacturing method for thick electrode sheets provided in this invention have excellent pattern control and shaping capabilities, and can realize efficient and large-scale production of thick electrode sheets with channel patterns. Furthermore, the manufacturing method of this invention can effectively improve the energy density, rate performance and service life of lithium batteries. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the channel structure in a thick electrode sheet of the prior art.

[0023] Figure 2 This is a flowchart illustrating a method for manufacturing a thick electrode sheet according to an embodiment of this application.

[0024] Figure 3 This is a schematic diagram of the channel structure in a thick electrode sheet according to an embodiment of this application.

[0025] Figure 4 This is a comparison of the rate performance of two positive electrodes: Example 1 (positive electrode with a channel pattern formed by adhesive jet printing) and Comparative Example 1 (positive electrode without a channel pattern).

[0026] Figure 5 This is a comparison of the cycle performance of the positive electrode capacity of Example 1 (positive electrode with a channel pattern formed by adhesive jet printing) and Comparative Example 1 (positive electrode without a channel pattern). Detailed Implementation

[0027] like Figure 2 The diagram shown is a schematic flow chart of a manufacturing method according to an embodiment of this application, including the following steps:

[0028] S100 Preparation of the spreading powder: The positive electrode active material particles are thoroughly mixed with the conductive agent to obtain the positive electrode spreading powder required in the binder jet printing additive manufacturing, or the negative electrode active material particles are thoroughly mixed with the conductive agent to obtain the negative electrode spreading powder required in the binder jet printing additive manufacturing.

[0029] S200, Powder Spreading and Printing: At the powder spreading and printing station, the positive electrode powder or the negative electrode powder is spread and printed layer by layer onto the battery current collector, and a predetermined channel pattern and a predetermined thickness are formed during the layer-by-layer powder spreading and printing process.

[0030] S300: The battery current collector that has been coated and printed with powder is sent out from the powder coating and printing station, and at the same time, the battery current collector to be coated and printed with powder is sent to the powder coating and printing station for the next cycle of layer-by-layer powder coating and printing.

[0031] S400. Repeat steps S200 and S300 above until the manufacturing of the thick electrode positive sheet or the thick electrode negative sheet is completed.

[0032] To better understand the above technical solutions, the following is in conjunction with the appendix. Figure 2-3 The present invention will be further described below with reference to specific embodiments, wherein the same reference numerals denote the same parts unless otherwise specifically stated. It should be emphasized that the following description is merely exemplary and not intended to limit the scope or application of the invention. The background section of the invention may contain background information about the problems or environment of the invention, and is not necessarily a description of prior art. Therefore, the content included in the background section is not an admission of prior art by the applicant.

[0033] Example 1

[0034] A method for manufacturing a thick electrode sheet, used to manufacture a thick positive electrode sheet having a predetermined channel pattern, includes the following steps:

[0035] S100. Preparation of the spreading powder: The positive electrode active material particles are thoroughly mixed with a conductive agent to obtain the positive electrode spreading powder required for binder jet printing additive manufacturing. The particle size distribution range of the positive electrode active material particles is preferably 1-10 μm. The conductive agent is preferably conductive carbon black, and the mass ratio of the positive electrode active material particles to the conductive carbon black is (80-90):(10-20). Specifically, nickel-cobalt-manganese ternary positive electrode active material particles with a mass ratio of 9:1 are thoroughly mixed with conductive carbon black as the spreading powder required for binder jet printing additive manufacturing. The D50 of the ternary positive electrode active material particles is 5 μm. In this step, the positive electrode active material particles can also be replaced with negative electrode active material particles. When the electrode active material particles are positive electrode active material particles, the resulting spreading powder is a positive electrode spreading powder; when the electrode active material particles are negative electrode active material particles, the resulting spreading powder is a negative electrode spreading powder.

[0036] S200, Powder Spreading and Printing: At the powder spreading and printing station, the positive electrode powder is spread layer by layer and printed onto the battery current collector using binder jetting technology. During the layer-by-layer powder spreading and printing process, a predetermined channel pattern and a predetermined thickness are formed. The predetermined channel pattern can be as follows: Figure 3 The channel pattern shown can also be other forms of channel pattern, and the specific shape and structure of the channel can be the same as... Figure 1 The results may be the same or different. In step S200, the powder-laying printing is preferably performed using a binder jet printing additive manufacturing method. The binder used is at least one of polyvinylidene fluoride, hydroxyethyl cellulose, hydroxypropyl cellulose, and ethyl cellulose. The binder also contains a dispersant, which is at least one of N-methylpyrrolidone, acetonitrile, ethanol, and isopropanol. The thickness of each layer can be controlled between 2-50 μm, preferably around 10 μm. In this embodiment, specifically, the binder used is polyvinylidene fluoride resin, and the dispersant is N-methylpyrrolidone, wherein the mass ratio of binder:dispersant:the positive electrode powder being laid is 10:1:9, ultimately achieving an electrode sheet with a channel pattern and a sheet thickness of 130 μm. The battery current collector is copper foil or aluminum foil; the positive electrode active material particles are at least one of lithium cobalt oxide, lithium iron phosphate, lithium manganese oxide, and ternary positive electrode material particles; the negative electrode active material particles are at least one of silicon, silicon carbide, and lithium titanate; and the conductive agent is conductive carbon black.

[0037] Furthermore, the thick positive electrode sheet with the predetermined channel pattern can be further heated and cured for shaping. The heating and curing temperature can be 60-120℃, preferably 100-120℃. Figure 2 As shown, the thick electrode positive electrode sheet includes a current collector 20 and a solidified positive electrode material 10 located thereon, the positive electrode material 10 having a predetermined channel pattern 101.

[0038] S300: The battery current collector that has already been powder-coated and printed is sent out from the powder-coating printing station, and at the same time, the battery current collector to be powder-coated and printed is transported to the powder-coating printing station for the next cycle of layer-by-layer powder coating and printing. The battery current collector is transported by connecting a battery current collector reel to a conveyor belt, and a blank area for cutting is left between adjacent powder-coated and printed battery current collectors. The conveyor belt speed is 1-10m per minute, which can be determined according to the size of the product, the performance of the printing equipment, etc. In this embodiment, specifically, the aluminum foil current collector reel is connected to the conveyor belt, and the conveyor belt introduces the current collector into the adhesive jet printing working area. The conveyor belt speed is 5m per minute. After the adhesive jet printing in this area is completed, the conveyor belt drives the introduction of a new current collector to be printed, so as to realize continuous additive manufacturing printing on the current collector. Simultaneously, the interval of continuous printing in this step is controlled. The electrode patterns are, for example, rectangles of 40μm × 30μm or squares of 50μm × 50μm, with a 25μm gap between every two adjacent rectangular electrode patterns. This gap area is not used for additive manufacturing printing and serves as a blank area for cutting. This blank area for cutting can be used for subsequent laser cutting of the electrode sheets, separating the mass-produced, connected electrode sheets into individual units without introducing contamination or byproducts.

[0039] The electrode sheet having the predetermined channel pattern 101 is heated and dried at 80°C and solidified to obtain the desired thick electrode positive electrode sheet.

[0040] S400. Repeat steps S200 and S300 above until the manufacturing of the thick electrode positive electrode sheet is completed.

[0041] The channel pattern in this embodiment is as follows: Figure 3 As shown, its channel structure is relatively simple, but those skilled in the art will understand that by using adhesive jet printing additive manufacturing to form the channel structure, more complex channel structures can be achieved to fully utilize the advantages of thick electrodes. For example, in other embodiments, the predetermined channel pattern is mesh-like, such as a crisscrossing mesh or a spider web-like mesh. In other embodiments, the predetermined channel pattern may have two or more layers, and the channel patterns of adjacent layers may be the same or different. Furthermore, the two or more layers of the predetermined channel pattern are at least partially interconnected, which can further reduce the penetration depth (distance) and increase the total volume of the channel structure.

[0042] The manufacturing method of the thick electrode sheet in this embodiment is flexible and efficient, and can be applied to products of various sizes and various channel pattern structures, thus having broad application prospects.

[0043] This embodiment can also adopt the following modified scheme:

[0044] The positive electrode active material particles in the aforementioned step S100 can be replaced with an equal amount of lithium cobalt oxide and nickel cobalt manganese ternary positive electrode active material particles uniformly mixed in a molar ratio of 1:2, with the rest remaining unchanged, to achieve essentially the same technical effect.

[0045] By replacing the adhesive in step S200 with equal amounts of ethyl cellulose and polyvinylidene fluoride mixed uniformly in a mass ratio of 1:2, while keeping the rest unchanged, the same technical effect can be achieved.

[0046] By replacing the dispersant in step S200 with equal amounts of acetonitrile and isopropanol mixed uniformly in a mass ratio of 1:2, while keeping the rest unchanged, the same technical effect can be achieved.

[0047] Comparative Example 1

[0048] This embodiment provides a method for preparing a thick electrode sheet for a high-rate lithium-ion battery, the method comprising the following steps:

[0049] (1) Mix nickel-cobalt-manganese ternary positive electrode active particles with conductive carbon black at a mass ratio of 9:1 to form a powder to be laid in the additive manufacturing process of jet printing as a binder. The D50 of the ternary positive electrode active particles is 5μm.

[0050] (2) The powder prepared in (1) is spread onto the aluminum foil current collector. Through the adhesive spraying technology, the powder is spread layer by layer, the adhesive is sprayed, and the printing is done layer by layer. The adhesive used is polyvinylidene fluoride resin, the dispersant is N-methylpyrrolidone, and the mass ratio of adhesive:dispersant:positive electrode precursor (i.e., the powder to be spread) is 10:1:9. Finally, an electrode sheet with a channel pattern is achieved, and the electrode sheet thickness is 130μm.

[0051] (3) Connect the aluminum foil current collector roll to the conveyor belt. The conveyor belt introduces the current collector into the working area of ​​the adhesive jet printing. The conveyor belt speed is 5m per minute. After the adhesive jet printing in this area is completed, the conveyor belt drives the introduction of a new current collector to be printed, so as to realize continuous additive manufacturing printing on the current collector.

[0052] (4) The positive electrode prepared by additive manufacturing in (1)-(3) is heated and dried at 80°C to obtain the desired positive electrode.

[0053] Performance testing:

[0054] The electrochemical performance of the thick electrode sheets of the high-rate lithium-ion batteries prepared in Example 1 and Comparative Example 1 was tested. The test method was as follows: a half-cell was assembled based on the prepared positive electrode with metallic lithium as the negative electrode. The battery charge-discharge range was 2.8-4.3V, and the constant current charge-discharge current density was 1C. The test temperature was 30℃. The results are as follows. Figure 4 , Figure 5 As shown. By Figure 4 This demonstrates that positive electrodes with channeled patterns manufactured by binder jet printing exhibit better kinetic rates, i.e., superior rate performance, compared to positive electrodes without channels. (From...) Figure 5 This indicates that positive electrodes with channel patterns manufactured by adhesive jet printing exhibit slower mass capacity decay compared to positive electrodes without channels, meaning they have better cycle stability.

[0055] Example 2

[0056] A method for manufacturing a high-rate-performance lithium-ion battery, wherein both the positive and negative electrodes are made of thick electrode sheets, which are prepared by any of the manufacturing methods described above. The high-rate-performance lithium-ion battery obtained through this embodiment can effectively improve the energy density, rate performance, and lifespan of lithium batteries, and is also suitable for efficient, large-scale production.

[0057] In addition, in other embodiments, only the positive electrode can be prepared by the manufacturing method described in any of the above-mentioned methods, or only the negative electrode can be prepared by the manufacturing method described in any of the above-mentioned methods. Those skilled in the art will understand that high-rate lithium-ion batteries can also be obtained, and the energy density, rate performance and service life of lithium batteries can be effectively improved compared with the prior art. At the same time, it is also suitable for efficient and large-scale production.

[0058] Although preferred embodiments of the invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including both the preferred embodiments and all changes and modifications falling within the scope of the invention.

[0059] Without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of the different embodiments or examples.

[0060] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A method of manufacturing a thick electrode tab, characterized by, The method comprises the following steps: S100, preparation of powder laying, fully mixing electrode active material particles and conductive agent to obtain powder laying required in binder jet printing additive manufacturing; S200, powder laying printing, layer-by-layer powder laying and printing of the powder laying on the battery current collector at the powder laying printing station, and forming a predetermined channel pattern during the layer-by-layer powder laying and printing, the predetermined channel pattern has two or more layers, the predetermined channel patterns of adjacent layers are the same or different, and the predetermined channel patterns of two or more layers are at least partially connected to each other; S300, the battery current collector after powder laying printing is sent out from the powder laying printing station, and the battery current collector to be powder laid and printed is transported to the powder laying printing station in the form of a battery current collector reel connected to a conveying belt for the next cycle of layer-by-layer powder laying and printing, and a blank area for cutting is left between the battery current collectors of adjacent two powder laying printing; wherein the "layer-by-layer powder laying and printing" in steps S200 and S300 is realized by binder jet printing additive manufacturing technology, and the binder used is at least one of polyvinylidene fluoride, hydroxyethyl cellulose, hydroxypropyl cellulose, and ethyl cellulose; wherein the conveying speed of the conveying belt is 1-10 m per minute; S400, repeating the above steps S200 and S300 until the manufacturing of the thick electrode positive plate or the thick electrode negative plate is completed.

2. The method of manufacturing a thick electrode sheet according to claim 1, wherein It also comprises a heating and curing forming step, that is, after the step S200 or the step S300, the thick electrode plate after powder laying printing and forming a channel pattern is subjected to heating and curing forming treatment.

3. The method of manufacturing a thick electrode sheet according to claim 1, wherein In the step S100, the electrode active material particles are positive electrode active material particles or negative electrode active material particles; When the electrode active material particles are positive electrode active material particles, the obtained powder laying is positive electrode powder laying, and when the electrode active material particles are negative electrode active material particles, the obtained powder laying is negative electrode powder laying.

4. The method of manufacturing a thick electrode sheet according to claim 3, wherein The battery current collector is a copper foil or an aluminum foil, and the positive electrode active material particles are at least one of lithium cobaltate, lithium iron phosphate, lithium manganate, and ternary positive electrode material particles; The negative electrode active material particles are at least one of silicon, silicon-carbon, and lithium titanate; The conductive agent is conductive carbon black.

5. The method of making a thick electrode sheet as claimed in claim 2, wherein The temperature of the heating and curing forming is 100-120°C.

6. A method of manufacturing a high rate capability lithium-ion battery comprising a positive electrode and a negative electrode, characterized in that, The positive electrode and / or the negative electrode are made of a thick electrode plate prepared by the manufacturing method according to any one of claims 1-5.

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