Solid-state battery and method of manufacturing the same

Abstract

The application provides a solid-state battery and a preparation method thereof. The preparation method of the solid-state battery comprises the following steps: obtaining a positive electrode sheet, a negative electrode sheet and a separator, wherein the positive electrode sheet is attached with a positive electrode slurry layer, the positive electrode slurry layer comprises a lithium-rich agent, a positive electrode active material, a porous solid-state electrolyte, a positive electrode binder and a conductive agent, the negative electrode sheet is attached with a negative electrode slurry layer, and the negative electrode slurry layer is coated with a porous solid-state electrolyte layer; performing a layer-stacking-into-shell treatment on the positive electrode sheet, the separator and the negative electrode sheet, so that the positive electrode sheet and the negative electrode sheet are arranged in a separated mode through the separator and are accommodated in a battery shell; injecting an electrolyte into the battery shell for infiltration solid-state treatment, so that the electrolyte is adsorbed on the positive electrode sheet, the separator and the porous solid-state electrolyte layer; and packaging and forming the battery shell to obtain the solid-state battery. The preparation method of the solid-state battery can better realize the reduction of the impedance of the battery, and further ensure the rate performance and temperature rise performance of the battery.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of batteries, in particular to a solid-state battery and a preparation method thereof. BACKGROUND

[0002] In the solid-state battery, a solid-state electrolyte is used instead of an electrolyte, such as the invention patent application with the application number CN202410129968.8, which forms a lithium supplement layer, an active layer, and an electrolyte layer in sequence on at least one side of the current collector, and the electrolyte layer is formed on the active layer by coating. The process of coating the electrolyte layer on the active layer requires high requirements, otherwise there may be a local non-adhesion contact between the electrolyte layer and the active layer, which may cause high impedance of the battery and affect the rate performance and temperature rise performance of the battery.

[0003] In order to reduce the influence of the rate performance and temperature rise performance of the battery, the solid-state electrolyte is currently compounded with slurry and coated on the current collector, such as the invention patent application with the application number CN202311321485.X. However, the addition of the solid-state electrolyte greatly reduces the energy density of the battery, and the preparation of the solid-state electrolyte still needs to make the positive electrode slurry layer contact with the solid-state electrolyte layer on the separator to form a solid-state battery. Therefore, the local adhesion effect of the positive electrode slurry layer and the solid-state electrolyte layer is poor, which may cause high impedance of the battery and affect the rate performance and temperature rise performance of the battery. SUMMARY

[0004] The purpose of the present application is to overcome the deficiencies in the prior art and provide a solid-state battery and a preparation method thereof, which can better reduce the impedance of the battery and ensure the rate performance and temperature rise performance of the battery.

[0005] The purpose of the present application is achieved by the following technical solutions:

[0006] A preparation method of a solid-state battery, comprising the following steps:

[0007] Obtaining a positive electrode sheet, a negative electrode sheet, and a separator, wherein the positive electrode sheet is attached with a positive electrode slurry layer, the positive electrode slurry layer comprises a lithium-rich agent, a positive electrode active material, a porous solid-state electrolyte, a positive electrode binder, and a conductive agent, the negative electrode sheet is attached with a negative electrode slurry layer, and the negative electrode slurry layer is coated with a porous solid-state electrolyte layer;

[0008] Stacking the positive electrode sheet, the separator, and the negative electrode sheet into a shell to dispose the positive electrode sheet and the negative electrode sheet apart by the separator and accommodate them in a battery shell;

[0009] Injecting an electrolyte into the battery shell for infiltration and solid-state treatment to adsorb the electrolyte on the positive electrode sheet, the separator, and the porous solid-state electrolyte layer.

[0010] The battery shell is packaged and formed to obtain a solid-state battery.

[0011] In one embodiment, the positive electrode slurry layer comprises the following components by mass fraction:

[0012] Lithium-rich agent 3-5 parts;

[0013] Positive electrode active material 88-92 parts;

[0014] Porous solid-state electrolyte 6-10 parts;

[0015] Positive electrode binder 1-2 parts;

[0016] Conductive agent 0.5-1.5 parts.

[0017] In one embodiment, the lithium-rich agent is lithium-rich lithium nickelate and / or lithium-rich lithium ironate.

[0018] In one embodiment, the positive electrode active material is at least one of lithium manganate, lithium nickel cobalt manganate, lithium iron phosphate, lithium manganese iron phosphate, lithium cobaltate, and lithium nickel cobalt aluminate.

[0019] In one embodiment, the positive electrode binder is at least one of polyvinylidene fluoride, polyvinylpyrrolidone, polymethyl methacrylate, polyacrylonitrile, and polytetrafluoroethylene.

[0020] In one embodiment, the porous solid-state electrolyte layer comprises the following components by mass fraction:

[0021] Porous solid-state electrolyte 55-70 parts;

[0022] Conductive agent 8-30 parts;

[0023] Negative electrode binder 8-25 parts.

[0024] In one embodiment, the porous solid-state electrolyte is porous lithium aluminum titanium phosphate, porous lithium lanthanum titanium oxide, porous lithium lanthanum zirconium oxide, or porous lithium polysulfide.

[0025] In one embodiment, the conductive agent is at least one of carbon black, conductive graphite, carbon nanotubes, and graphene.

[0026] In one embodiment, the particle size D50 of the porous solid-state electrolyte is ≤270 nm.

[0027] In one embodiment, the negative electrode binder is butadiene styrene rubber.

[0028] In one of the embodiments, the thickness of the positive electrode slurry layer is 230-290 mu m.

[0029] In one of the embodiments, the area density of the positive electrode slurry layer is 450-550 g / m 2 2 .

[0030] In one of the embodiments, the particle size D50 of the lithium-rich agent is 500 nm-1 mu m.

[0031] In one of the embodiments, the thickness of the porous solid electrolyte layer is 0.8-2 mu m.

[0032] In one of the embodiments, the positive electrode slurry layer is obtained by coating a positive electrode slurry on a positive electrode sheet;

[0033] The preparation method of the positive electrode slurry comprises the following steps:

[0034] Obtaining a porous solid electrolyte dispersion liquid and a lithium-rich agent;

[0035] Performing airflow dispersion treatment on the lithium-rich agent to make the lithium-rich agent in a dispersed state under the action of airflow;

[0036] Performing ultrasonic atomization coating operation on the lithium-rich agent in the dispersed state by using the porous solid electrolyte dispersion liquid to make the porous solid electrolyte dispersion liquid ultrasonic atomization dispersion and be carried to the surface of the lithium-rich agent by gas and coated on the lithium-rich agent to obtain a coated lithium-rich agent;

[0037] Adding a positive electrode active material, a positive electrode binder and a conductive agent to the coated lithium-rich agent to mix to obtain the positive electrode slurry.

[0038] A solid-state battery is prepared by the preparation method of the solid-state battery according to any one of the embodiments.

[0039] Compared with the prior art, the present application has at least the following advantages:

[0040] The preparation method of the solid-state battery of the present application makes the positive electrode slurry attached to the positive electrode sheet contain the lithium-rich agent and the porous solid electrolyte, and the porous solid electrolyte layer is attached to the negative electrode slurry layer of the negative electrode sheet, and then cooperates with the injected electrolyte to make the electrolyte be fully absorbed in the positive electrode slurry layer, the separator and the porous solid electrolyte layer, and there is actually no flowable electrolyte in the battery shell, the preparation of the solid-state battery is realized, and the electrolyte and the porous solid electrolyte cooperate to realize the full contact between the positive electrode sheet, the separator and the negative electrode sheet, and form a channel conducive to the conduction of lithium ions, which better realizes the reduction of the impedance of the battery, and effectively improves the rate performance and temperature rise performance of the solid-state battery.​ Attached Figure Description

[0041] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0042] Figure 1 This is a flowchart of a method for preparing a solid-state battery according to an embodiment of the present invention. Detailed Implementation

[0043] To facilitate understanding of the present invention, a more complete description will be given below with reference to the accompanying drawings. Preferred embodiments of the invention are shown in the drawings. However, the invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a thorough and complete understanding of the disclosure of the invention.

[0044] It should be noted that when an element is referred to as being "fixed to" another element, it can be directly attached to the other element or there may be an intervening element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or there may be an intervening element. The terms "vertical," "horizontal," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only possible implementation.

[0045] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0046] The application provides a solid-state battery preparation method. The solid-state battery preparation method comprises the following steps: obtaining a positive electrode sheet, a negative electrode sheet and a separator, wherein the positive electrode sheet is attached with a positive electrode slurry layer, the positive electrode slurry layer comprises a lithium-rich agent, a positive electrode active material, a porous solid-state electrolyte, a positive electrode binder and a conductive agent, the negative electrode sheet is attached with a negative electrode slurry layer, and the negative electrode slurry layer is coated with a porous solid-state electrolyte layer; performing a layer-stacking-into-shell treatment on the positive electrode sheet, the separator and the negative electrode sheet, so that the positive electrode sheet and the negative electrode sheet are arranged separately by the separator and are accommodated in a battery shell; injecting an electrolyte into the battery shell for infiltration and solid-state treatment, so that the electrolyte is adsorbed on the positive electrode sheet, the separator and the porous solid-state electrolyte layer; and packaging and forming the battery shell to obtain a solid-state battery.

[0047] The solid-state battery preparation method makes the positive electrode slurry attached to the positive electrode sheet contain the lithium-rich agent and the porous solid-state electrolyte, and the negative electrode slurry layer of the negative electrode sheet is attached with the porous solid-state electrolyte layer, and then cooperates with the injected electrolyte to make the electrolyte be fully adsorbed in the positive electrode slurry layer, the separator and the porous solid-state electrolyte layer, so that there is actually no flowable electrolyte in the battery shell, the preparation of the solid-state battery is realized, the electrolyte and the porous solid-state electrolyte cooperate to realize the full contact between the positive electrode sheet, the separator and the negative electrode sheet, and a channel conducive to lithium ion conduction is formed, the impedance of the battery is better reduced, and the rate performance and the temperature rise performance of the solid-state battery are effectively improved.

[0048] It should be noted that if the solid-state electrolyte is mixed in the positive electrode slurry and the negative electrode slurry, but is not a porous solid-state electrolyte, the infiltration effect of the electrolyte on the positive electrode sheet and the negative electrode sheet is poor, and it is difficult to make the electrolyte cooperate with the solid-state electrolyte to form a rapid conduction channel of lithium ions, and the impedance of the formed solid-state battery is relatively high.

[0049] If only the solid-state electrolyte layer coated on the positive electrode sheet and the negative electrode sheet is used to form the solid-state battery, if no electrolyte is injected, the impedance of the solid-state battery is greatly affected, and if the electrolyte is injected, the electrolyte and the solid-state electrolyte are difficult to form a rapid channel for lithium ion transmission, so the impedance of the formed solid-state battery is still relatively high.

[0050] In addition, if the solid-state electrolyte layer coated on the positive electrode sheet and the negative electrode sheet is not a porous solid-state electrolyte, the impedance of the formed solid-state battery is further relatively high.

[0051] It should be further noted that if the porous solid-state electrolyte on the negative electrode sheet is directly mixed in the negative electrode slurry and coated, the electrolyte of the negative electrode sheet will be fully absorbed in the negative electrode sheet, so more active materials are consumed to form the SEI film, so the rate performance and the cycle charging of the solid-state battery are greatly affected.

[0052] In order to better understand the preparation method of the solid-state battery of the present application, the preparation method of the solid-state battery of the present application is further explained as follows:

[0053] Please refer to Figure 1 The preparation method of the solid-state battery of an embodiment includes the following steps:

[0054] S100, obtaining a positive electrode sheet, a negative electrode sheet and a separator, wherein the positive electrode sheet is attached with a positive electrode slurry layer, the positive electrode slurry layer includes a lithium-rich agent, a positive electrode active material, a porous solid-state electrolyte, a positive electrode binder and a conductive agent, the negative electrode sheet is attached with a negative electrode slurry layer, and the negative electrode slurry layer is coated with a porous solid-state electrolyte layer. It can be understood that the positive electrode slurry of the positive electrode sheet contains the porous solid-state electrolyte, so that the porous structure of the porous solid-state electrolyte is beneficial to the construction of lithium ion conduction channels; in addition, the negative electrode slurry layer on the negative electrode sheet is attached with the porous solid-state electrolyte layer, which is beneficial to the construction of the solid-state battery.

[0055] S200, performing a layering into a shell treatment on the positive electrode sheet, the separator and the negative electrode sheet, so that the positive electrode sheet and the negative electrode sheet are arranged separately by the separator and are accommodated in the battery shell.

[0056] S300, injecting an electrolyte into the battery shell for infiltration and solid-state treatment, so that the electrolyte is adsorbed on the positive electrode sheet, the separator and the porous solid-state electrolyte layer. It can be understood that in the presence of the porous solid-state electrolyte in the positive electrode slurry of the positive electrode sheet and the porous solid-state electrolyte layer on the negative electrode slurry layer of the negative electrode sheet, the injection of the electrolyte is further matched, so that the electrolyte is fully adsorbed on the separator, and the electrolyte is also fully adsorbed in the porous solid-state electrolyte, so that the electrolyte in the battery shell is fully filled on the basis of no flow, and serves as a bridge for the conduction of lithium ions at the gap between the positive electrode sheet, the separator and the negative electrode sheet, thereby better reducing the impedance of the solid-state battery, better improving the rate performance and temperature rise performance of the solid-state battery, and in addition, the pores of the porous solid-state electrolyte in the positive electrode slurry are fully filled with the electrolyte, so that the porous solid-state electrolyte cooperates with the electrolyte to form a fast conduction channel for lithium ions, further improving the rate performance and cycle performance of the solid-state battery.

[0057] S400, packaging and forming the battery shell to obtain a solid-state battery.

[0058] The preparation method of the solid-state battery described above makes the positive electrode slurry attached on the positive electrode sheet contain the lithium-rich agent and the porous solid-state electrolyte, and the porous solid-state electrolyte layer is attached on the negative electrode slurry layer of the negative electrode sheet, and then cooperates with the injected electrolyte, so that the electrolyte is fully absorbed in the positive electrode slurry layer, the separator and the porous solid-state electrolyte layer, and there is actually no flowable electrolyte in the battery shell, the preparation of the solid-state battery is realized, and the electrolyte and the porous solid-state electrolyte cooperate to realize the full contact between the positive electrode sheet, the separator and the negative electrode sheet, and form a channel conducive to lithium ion conduction, better realizing the reduction of the impedance of the battery, and then effectively improving the rate performance and temperature rise performance of the solid-state battery.

[0059] In one of the embodiments, the positive electrode slurry layer comprises the following components by mass fraction: lithium-rich agent 3-5 parts; positive electrode active material 88-92 parts; porous solid-state electrolyte 6-10 parts; positive electrode binder 1-2 parts; and conductive agent 0.5-1.5 parts.

[0060] In one of the embodiments, the lithium-rich agent is lithium-rich lithium nickelate and / or lithium-rich lithium ironate.

[0061] In one of the embodiments, the positive electrode active material is at least one of lithium manganeseate, lithium nickel cobalt manganeseate, lithium iron phosphate, lithium manganese iron phosphate, lithium cobaltate, and lithium nickel cobalt aluminate.

[0062] In one of the embodiments, the positive electrode binder is at least one of polyvinylidene fluoride, polyvinylpyrrolidone, polymethyl methacrylate, polyacrylonitrile, and polytetrafluoroethylene.

[0063] In one of the embodiments, the porous solid-state electrolyte layer comprises the following components by mass fraction: porous solid-state electrolyte 55-70 parts; conductive agent 8-30 parts; and negative electrode binder 8-25 parts.

[0064] In one of the embodiments, the porous solid-state electrolyte is porous lithium aluminum titanium phosphate, porous lithium lanthanum titanium oxide, porous lithium lanthanum zirconium oxide, or porous polyphosphorus lithium sulfide.

[0065] In one of the embodiments, the conductive agent is at least one of carbon black, conductive graphite, carbon nanotube, and graphene.

[0066] In one of the embodiments, the particle size D50 of the porous solid-state electrolyte is ≤270 nm. Further, the particle size of the porous solid-state electrolyte is 100-500 nm. Further, the porosity of the porous solid-state electrolyte is 45-60%.

[0067] In one of the embodiments, the negative electrode binder is butadiene styrene rubber.

[0068] In one of the embodiments, the thickness of the positive electrode slurry layer is 230-290 μm.

[0069] In one embodiment, the face density of the positive electrode slurry layer is 450 g / m 2 ~ 550 g / m 2 .

[0070] In one embodiment, the particle size D50 of the lithium-rich agent is 500 nm ~ 1 μm.

[0071] In one embodiment, the thickness of the porous solid electrolyte layer is 0.8 μm ~ 2 μm.

[0072] In one embodiment, the positive electrode slurry layer is obtained by coating a positive electrode slurry on a positive electrode sheet, followed by drying. Further, the drying temperature is 100 °C ~ 150 °C. It can be understood that the operation of drying after coating the positive electrode slurry is the same as the conventional one, which will not be described here.

[0073] Further, the preparation method of the positive electrode slurry comprises the following steps:

[0074] obtaining a porous solid electrolyte dispersion and a lithium-rich agent;

[0075] performing airflow dispersion treatment on the lithium-rich agent to make the lithium-rich agent in a dispersed state under the action of airflow;

[0076] performing ultrasonic atomization coating operation on the lithium-rich agent in the dispersed state with the porous solid electrolyte dispersion to make the porous solid electrolyte dispersion ultrasonic atomization dispersed and carried to the surface of the lithium-rich agent by gas and coated on the lithium-rich agent, to obtain coated lithium-rich agent;

[0077] adding a positive electrode active material, a positive electrode binder and a conductive agent to the coated lithium-rich agent for mixing operation to obtain a positive electrode slurry.

[0078] It can be understood that the lithium-rich agent is coated in the porous solid electrolyte, which reduces the interaction of the lithium-rich agent with the polyvinylidene fluoride when added to the positive electrode slurry, reduces the influence on the preparation of the positive electrode slurry, and reduces the intensification of the by-products of the lithium-rich agent and the electrolyte. In addition, the lithium ions in the lithium-rich agent can quickly supplement the lack of lithium ions, thereby effectively improving the cycle performance of the solid-state battery.

[0079] In one embodiment, a fluidized bed is used to perform airflow dispersion treatment on the lithium-rich agent.

[0080] In one embodiment, the lithium-rich agent is subjected to airflow dispersion treatment, and the specific steps are as follows: the lithium-rich agent is added to the fluidized bed, the airflow speed of the fluidized bed is 0.1 m / s ~ 0.6 m / s, the temperature is 50 °C ~ 120 °C, and the fluidization time is 3 min ~ 7 min.

[0081] In one of the embodiments, the porous solid electrolyte dispersion is obtained by adding a solvent and a dispersant to the porous solid electrolyte and mixing and stirring them together, at a stirring speed of 600 rpm to 800 rpm for a stirring time of 0.5 h to 2 h. Further, the solvent is at least one of N-methyl pyrrolidone, dimethylformamide, tetrahydrofuran, acetonitrile, acetone, ethanol, and toluene. Further, the dispersant is at least one of polyvinylpyrrolidone, menhaden oil, and polyethylene glycol. Further, the porous solid electrolyte dispersion includes the following components in the following amounts by mass: 0.1 parts to 0.6 parts of the dispersant; 45 parts to 70 parts of the porous solid electrolyte; and 16 parts to 25 parts of the solvent.

[0082] In one of the embodiments, the porous solid electrolyte dispersion is used to perform ultrasonic atomization coating on the lithium-rich agent in a dispersed state, by placing the porous solid electrolyte dispersion in an ultrasonic atomizer to perform ultrasonic atomization, at a vibration frequency of 0.8 Hz to 1.2 Hz, a power of 35 W to 50 W, a nozzle aperture of 5 μm to 12 μm, and an atomization amount of 1 mL / min, to form porous solid electrolyte dispersion droplets, which are carried to the lithium-rich agent by the airflow of a fluidized bed, so that the porous solid electrolyte dispersion droplets contact the lithium-rich agent and coat the surface of the lithium-rich agent. Further, the airflow of the fluidized bed is formed by introducing an inert gas. Further, the inert gas is nitrogen or / and helium.

[0083] In one of the embodiments, the coated lithium-rich agent is added to an active cathode material, a cathode binder, and a conductive agent to perform slurry treatment, by adding the active cathode material and the cathode binder to the coated lithium-rich agent to perform primary mixing, to obtain a mixture. Further, the stirring speed of the primary mixing is 500 rpm to 600 rpm, and the stirring time is 0.5 h to 1 h. Further, a solvent is added to the mixture to perform slurry treatment. Further, the solvent is added to the mixture to form a slurry by stirring, at a stirring speed of 600 rpm to 700 rpm for a stirring time of 0.5 h to 1 h. Further, a conductive agent is added to the slurry-treated mixture to perform secondary mixing, to obtain a cathode slurry. Further, the stirring speed of the secondary mixing is 800 rpm to 900 rpm, and the stirring time is 0.8 h to 2 h. Further, the solvent is at least one of N-methyl pyrrolidone, dimethylformamide, tetrahydrofuran, acetonitrile, acetone, ethanol, and toluene.

[0084] In one of the embodiments, the negative electrode slurry layer is obtained by coating a negative electrode slurry on the negative electrode sheet, followed by drying. The negative electrode slurry comprises the following components in parts by mass: single-walled carbon nanotubes 1-2 parts; sodium carboxymethyl cellulose 1-2 parts; butyl rubber emulsion 4-5 parts; graphite 10-15 parts; silicon oxide 80-89 parts; and deionized water 95-99 parts. Further, the drying temperature is 90-110°C. It is understood that the operation of drying after coating the negative electrode slurry is the same as the conventional operation, which is not described herein. Further, the preparation method of the negative electrode slurry is as follows: the graphite and silicon oxide are stirred at a speed of 600-800 rpm for 0.5-1.5 h, then the single-walled carbon nanotubes are added and mixed at a speed of 600-800 rpm for 0.5-1.5 h, then the sodium carboxymethyl cellulose, butyl rubber emulsion and deionized water are added and homogenized at a speed of 1200-1500 rpm for 0.5-1 h. Further, the thickness and areal density of the negative electrode slurry layer are the same as the conventional, which is not described herein.

[0085] In one of the embodiments, the porous solid electrolyte layer is obtained by coating a porous solid electrolyte slurry on the negative electrode slurry layer, followed by drying. Further, the drying temperature is 100-150°C. Further, the thickness of the porous solid electrolyte layer is 1-3 μm. Further, the preparation method of the porous solid electrolyte slurry comprises the following steps: the porous solid electrolyte, conductive agent and negative electrode binder are placed in a solvent and stirred at a speed of 800-1000 rpm for 1.5-2 h. Further, the solvent is at least one of N-methylpyrrolidone, dimethylformamide, tetrahydrofuran, acetonitrile, acetone, ethanol and toluene.

[0086] In one of the embodiments, the separator is a polyethylene non-woven fabric separator.

[0087] In one of the embodiments, the electrolyte is a non-aqueous electrolyte. Further, the electrolyte is a LiPF6 non-aqueous electrolyte, which is the LiPF6 electrolyte used in the conventional lithium ion battery, which is not described herein.

[0088] In one of the embodiments, the operation of liquid injection packaging and formation is the same as the operation of the conventional lithium battery, which is not described herein.

[0089] The application also provides a solid-state battery prepared by the preparation method of the solid-state battery of any one of the above embodiments. Further, in the present embodiment, the preparation method of the solid-state battery comprises the following steps: obtaining a positive electrode sheet, a negative electrode sheet and a separator, wherein the positive electrode sheet is attached with a positive electrode slurry layer, the positive electrode slurry layer comprises a lithium-rich agent, a positive electrode active material, a porous solid-state electrolyte, a positive electrode binder and a conductive agent, the negative electrode sheet is attached with a negative electrode slurry layer, and the negative electrode slurry layer is coated with a porous solid-state electrolyte layer; performing a layering-into-shell treatment on the positive electrode sheet, the separator and the negative electrode sheet, so that the positive electrode sheet and the negative electrode sheet are arranged apart by the separator and are accommodated in a battery shell together; injecting an electrolyte into the battery shell for infiltration and solid-state treatment, so that the electrolyte is adsorbed on the positive electrode sheet, the separator and the porous solid-state electrolyte layer; and packaging and forming the battery shell to obtain the solid-state battery.

[0090] The solid-state battery described above is obtained by the preparation method of the solid-state battery, which effectively improves the rate performance and temperature rise performance of the solid-state battery.

[0091] Compared with the prior art, the present application has at least the following advantages:

[0092] The preparation method of the solid-state battery of the present application enables the positive electrode slurry attached to the positive electrode sheet to contain the lithium-rich agent and the porous solid-state electrolyte, and the negative electrode slurry layer of the negative electrode sheet is attached with the porous solid-state electrolyte layer, which, in combination with the injected electrolyte, enables the electrolyte to be fully adsorbed in the positive electrode slurry layer, the separator and the porous solid-state electrolyte layer, while there is actually no flowable electrolyte in the battery shell, thereby realizing the preparation of the solid-state battery, and the electrolyte and the porous solid-state electrolyte realize sufficient contact between the positive electrode sheet, the separator and the negative electrode sheet, and form a channel conducive to lithium ion conduction, thereby better realizing the reduction of the impedance of the battery, and effectively improving the rate performance and temperature rise performance of the solid-state battery.

[0093] Some specific embodiments are listed below. If % is mentioned, it means percentage by weight. It should be noted that the following examples do not exhaust all possible cases, and the materials used in the following examples, unless otherwise specified, can be obtained from commercial channels.

[0094] Example 1

[0095] Preparation of the positive electrode sheet:

[0096] 0.7 kg of porous lithium titanium aluminum phosphate with a porosity of 60% and a pore size D50 of 270 nm was added to 0.25 kg of N-methylpyrrolidone and 0.006 kg of polyvinylpyrrolidone and stirred and mixed, the stirring speed was 800 rpm, and the stirring time was 0.5 h, to obtain a porous lithium titanium aluminum phosphate dispersion liquid for use;

[0097] 0.5 kg of lithium-rich lithium nickelate with a D50 of 1 μm was added to a fluidized bed to be in a fluidized state by gas flow, the gas flow rate was 0.6 m / s, the temperature was 120°C, after 3 min of fluidization, the porous lithium aluminum titanium phosphate dispersion was added to an ultrasonic atomizer, the oscillation frequency was 1.2 HZ, the power was 50 W, the nozzle aperture was 12 μm, the atomization amount was 1 mL / min, and was brought into the fluidized bed through the nozzle and mixed and dried by the gas flow to obtain a lithium-rich material;

[0098] The lithium-rich material was added to 9.2 kg of lithium manganese oxide and 0.2 kg of polyvinylidene fluoride for stirring, the stirring speed was 600 rpm, the stirring time was 0.5 h, then 8.5 kg of N-methylpyrrolidone was added for stirring, the stirring speed was 700 rpm, the stirring time was 0.5 h, then 0.15 kg of multi-walled carbon nanotubes was added for stirring, the stirring speed was 900 rpm, the stirring time was 0.8 h, to obtain a positive electrode slurry and coated on an aluminum foil, and dried, the drying temperature was 150°C, to obtain a positive electrode sheet with a thickness of 290 μm and a surface density of 550 g / m 2 .

[0099] Negative electrode sheet preparation:

[0100] 1.5 kg of graphite and 8.9 kg of silicon oxide were stirred, the stirring speed was 800 rpm, the stirring time was 0.5 h, then 0.2 kg of single-walled carbon nanotubes was added for mixing, the stirring speed was 800 rpm, the stirring time was 0.5 h, then 0.2 kg of sodium carboxymethyl cellulose, 0.82 kg of butadiene-styrene rubber emulsion with a solid content of 60%, and 9.9 kg of deionized water were added for homogenization, the stirring speed was 1500 rpm, and the stirring time was 0.5 h, to obtain a negative electrode slurry and coated on a copper foil and dried, the drying temperature was 110°C, to form a negative electrode slurry layer on the copper foil, ready for use;

[0101] 7.0 kg of porous lithium aluminum titanium phosphate with a porosity of 60% and a pore size D50 of 270 nm, 3.0 kg of carbon nanotubes, and 2.5 kg of butadiene-styrene rubber were stirred and mixed together, the stirring speed was 1000 rpm, the stirring time was 1.5 h, then coated onto the side of the negative electrode slurry layer away from the copper foil and dried, the drying temperature was 150°C, to form a porous solid-state electrolyte layer with a thickness of 3 μm on the negative electrode slurry layer, to obtain a negative electrode sheet.

[0102] The positive electrode sheet, polyethylene non-woven separator, and negative electrode sheet were stacked and wound into an aluminum plastic shell, and then injected with LiPF6 electrolyte, with dimethyl carbonate added at a concentration of 1.2 mol / L and an addition amount of 52±0.75 g, so that the positive electrode sheet, separator, and negative electrode sheet were completely infiltrated, and there was no flowable state electrolyte, then packaged, formed, and obtained a battery.

[0103] Example 2

[0104] Positive electrode sheet preparation:

[0105] 0.6 kg of porous lithium titanium aluminum phosphate having a porosity of 52% and a pore size D50 of 180 nm was added to 0.15 kg of N-methylpyrrolidone, 0.07 kg of acetone, and 0.004 kg of polyvinylpyrrolidone, and stirred and mixed at a stirring speed of 700 rpm for 1.2 h to obtain a porous lithium titanium aluminum phosphate dispersion, which was used as is;

[0106] 0.4 kg of lithium-rich lithium nickelate having a D50 of 800 nm was added to a fluidized bed and brought into a fluidized state by a gas flow at a gas flow speed of 0.3 m / s and a temperature of 100°C, and after being fluidized for 5 min, the porous lithium titanium aluminum phosphate dispersion was added to an ultrasonic atomizer, oscillated at a frequency of 1.0 Hz and a power of 42 W, and sprayed through a nozzle having a pore size of 8 μm at an atomization amount of 1 mL / min into the fluidized bed and mixed and dried by the gas flow at the lithium-rich lithium nickelate to obtain a lithium-rich material;

[0107] The lithium-rich material was added to 9.0 kg of lithium cobaltate and 0.15 kg of polyvinylidene fluoride and stirred at a stirring speed of 550 rpm for 0.8 h, followed by adding 8.0 kg of N-methylpyrrolidone and stirring at a stirring speed of 650 rpm for 0.8 h, and then adding 0.1 kg of multi-walled carbon nanotubes and stirring at a stirring speed of 850 rpm for 1.5 h to obtain a positive electrode slurry, which was coated on an aluminum foil and dried at a drying temperature of 120°C to obtain a positive electrode sheet having a thickness of 260 μm and a surface density of 500 g / m 2 .

[0108] Negative electrode sheet preparation:

[0109] 1.2 kg of graphite and 8.5 kg of silicon oxide were stirred at a stirring speed of 700 rpm for 0.2 h, followed by adding 0.15 kg of single-walled carbon nanotubes and mixing at a stirring speed of 700 rpm for 1.1 h, and then adding 0.15 kg of sodium carboxymethyl cellulose, 0.72 kg of a butadiene-styrene rubber emulsion having a solid content of 60%, and 9.7 kg of deionized water and homogenizing at a stirring speed of 1350 rpm for 0.8 h to obtain a negative electrode slurry, which was coated on a copper foil and dried at a drying temperature of 100°C to form a negative electrode slurry layer on the copper foil, which was used as is;

[0110] The porous lithium titanium aluminum phosphate 6.2 kg having a porosity of 52% and a pore size D50 of 180 nm, 1.8 kg carbon nanotubes, and 1.8 kg butadiene-styrene rubber were stirred and mixed at a stirring speed of 900 rpm for 1.8 h, and then coated on a side of the negative electrode slurry layer away from the copper foil and dried at a drying temperature of 120°C to form a porous lithium titanium aluminum phosphate layer having a thickness of 2 μm on the negative electrode slurry layer, thereby obtaining a negative electrode sheet.

[0111] After the positive electrode sheet, the polyethylene non-woven fabric separator, and the negative electrode sheet were stacked and roll-wound, the roll-wound product was put into an aluminum plastic case, and electrolyte solution was injected thereinto. The electrolyte solution was LiPF6 electrolyte solution to which dimethyl carbonate was added at a concentration of 1.2 mol / L and in an amount of 52 ± 0.75 g, so that the positive electrode sheet, the separator, and the negative electrode sheet were completely impregnated with the electrolyte solution without any flowable electrolyte solution. Then, the roll-wound product was packaged, and formation was performed, thereby obtaining a battery.

[0112] Example 3

[0113] Preparation of a positive electrode sheet:

[0114] The porous lithium titanium aluminum phosphate 0.55 kg having a porosity of 45% and a pore size D50 of 100 nm was stirred and mixed in 0.15 kg N-methylpyrrolidone, 0.05 kg ethanol, and 0.002 kg polyvinylpyrrolidone at a stirring speed of 600 rpm for 2 h, thereby obtaining a porous lithium titanium aluminum phosphate dispersion liquid.

[0115] The lithium-rich lithium iron phosphate 0.3 kg having a D50 of 500 nm was put into a fluidized bed and brought into a fluidized state by a gas flow at a gas flow rate of 0.1 m / s and a temperature of 50°C. After the fluidization for 7 min, the porous lithium titanium aluminum phosphate dispersion liquid was put into an ultrasonic atomizer, oscillated at a frequency of 0.8 Hz and a power of 35 W, and sprayed through a nozzle having a pore size of 5 μm at an atomizing amount of 1 mL / min into the fluidized bed, and mixed with the lithium-rich lithium iron phosphate by the gas flow and dried, thereby obtaining a lithium-rich material.

[0116] The lithium-rich material was stirred in 8.8 kg lithium cobalt oxide and 0.1 kg polyvinylidene fluoride at a stirring speed of 500 rpm for 1 h, and then stirred in 7.5 kg N-methylpyrrolidone at a stirring speed of 600 rpm for 1 h, and then stirred in 0.05 kg multi-walled carbon nanotubes at a stirring speed of 800 rpm for 2 h, thereby obtaining a positive electrode slurry which was coated on an aluminum foil and dried at a drying temperature of 100°C, thereby obtaining a positive electrode sheet having a thickness of 230 μm and an area density of 450 g / m 2 .

[0117] Preparation of a negative electrode sheet:

[0118] Stir 1.0 kg of graphite and 8.0 kg of silicon oxide at a stirring speed of 600 rpm for 1.5 h, then add 0.1 kg of single-walled carbon nanotubes and mix at a stirring speed of 600 rpm for 1.5 h, then add 0.1 kg of sodium carboxymethyl cellulose, 0.68 kg of a butadiene-styrene rubber emulsion having a solid content of 60%, and 9.5 kg of deionized water and homogenize at a stirring speed of 1200 rpm for 1 h to obtain a negative electrode slurry, coat the negative electrode slurry on a copper foil, and dry at a drying temperature of 90°C to form a negative electrode slurry layer on the copper foil, and wait for use;

[0119] Stir 5.5 kg of porous titanium aluminum lithium phosphate having a porosity of 45% and a pore size D50 of 100 nm, 0.8 kg of carbon nanotubes, and 0.8 kg of butadiene-styrene rubber together at a stirring speed of 800 rpm for 2 h, then coat the mixture on a side of the negative electrode slurry layer away from the copper foil and dry at a drying temperature of 100°C to form a 1-μm-thick porous titanium aluminum lithium phosphate layer on the negative electrode slurry layer, and obtain a negative electrode sheet.

[0120] After laminating and roll-winding the positive electrode sheet, the polyethylene non-woven membrane separator, and the negative electrode sheet, place them in an aluminum plastic shell, inject LiPF6 electrolyte, add dimethyl carbonate to a concentration of 1.2 mol / L, and add an amount of 52±0.75 g, so that the positive electrode sheet, the separator, and the negative electrode sheet are completely infiltrated, and there is no flowable electrolyte, then package, form, and obtain a battery.

[0121] Example 4

[0122] Positive electrode sheet preparation:

[0123] Add 0.4 kg of lithium-rich lithium nickelate having a D50 of 800 nm and 0.6 kg of porous titanium aluminum lithium phosphate having a porosity of 52% and a pore size D50 of 180 nm to 0.15 kg of N-methylpyrrolidone, 0.07 kg of acetone, and 0.004 kg of polyvinylpyrrolidone, stir and mix at a stirring speed of 700 rpm for 1.2 h, then add to 9.0 kg of lithium cobaltate and 0.15 kg of polyvinylidene fluoride and stir at a stirring speed of 550 rpm for 0.8 h, then add 8.0 kg of N-methylpyrrolidone and stir at a stirring speed of 650 rpm for 0.8 h, then add 0.1 kg of multi-walled carbon nanotubes and stir at a stirring speed of 850 rpm for 1.5 h to obtain a positive electrode slurry, coat the positive electrode slurry on an aluminum foil, and dry at a drying temperature of 120°C to obtain a positive electrode sheet having a thickness of 260 μm and an area density of 500 g / m 2 .

[0124] Negative electrode sheet preparation:

[0125] The 1.2 kg of graphite and 8.5 kg of silicon oxide were stirred at a stirring speed of 700 rpm for 0.2 h, then 0.15 kg of single-walled carbon nanotubes were added and mixed at a stirring speed of 700 rpm for 1.1 h, then 0.15 kg of sodium carboxymethyl cellulose, 0.72 kg of a butadiene-styrene rubber emulsion having a solid content of 60%, and 9.7 kg of deionized water were added and homogenized at a stirring speed of 1350 rpm for 0.8 h to obtain a negative electrode slurry, which was coated on a copper foil and dried at a temperature of 100°C to form a negative electrode slurry layer on the copper foil;

[0126] The 6.2 kg of porous titanium aluminum lithium phosphate having a porosity of 52% and a pore size D50 of 180 nm, 1.8 kg of carbon nanotubes, and 1.8 kg of butadiene-styrene rubber were stirred and mixed at a stirring speed of 900 rpm for 1.8 h, then coated on a side of the negative electrode slurry layer away from the copper foil and dried at a temperature of 120°C to form a porous titanium aluminum lithium phosphate layer having a thickness of 2 μm on the negative electrode slurry layer, thereby obtaining a negative electrode sheet.

[0127] The positive electrode sheet, the polyethylene non-woven separator, and the negative electrode sheet were stacked and wound, then placed in an aluminum plastic case, and liquid injection was performed. LiPF6 electrolyte was injected, and dimethyl carbonate was added at a concentration of 1.2 mol / L and an amount of 52 ± 0.75 g, so that the positive electrode sheet, the separator, and the negative electrode sheet were completely infiltrated, and there was no flowable electrolyte. Then, the battery was packaged, formed, and obtained.

[0128] Comparative Example 1

[0129] Preparation of a positive electrode sheet:

[0130] The 0.4 kg of lithium-rich lithium nickelate having a D50 of 800 nm and the 0.6 kg of porous titanium aluminum lithium phosphate having a porosity of 52% and a pore size D50 of 180 nm were added to 0.15 kg of N-methylpyrrolidone, 0.07 kg of acetone, and 0.004 kg of polyvinylpyrrolidone, and stirred and mixed at a stirring speed of 700 rpm for 1.2 h, then added to 9.0 kg of lithium cobaltate and 0.15 kg of polyvinylidene fluoride, and stirred at a stirring speed of 550 rpm for 0.8 h, then added to 8.0 kg of N-methylpyrrolidone, and stirred at a stirring speed of 650 rpm for 0.8 h, and then added to 0.1 kg of multi-walled carbon nanotubes, and stirred at a stirring speed of 850 rpm for 1.5 h to obtain a positive electrode slurry, which was coated on an aluminum foil and dried at a temperature of 120°C to obtain a positive electrode sheet having a thickness of 260 μm and an area density of 500 g / m 2 .

[0131] Preparation of a negative electrode sheet:

[0132] Stir 1.2 kg of graphite and 8.5 kg of silicon oxide at a stirring speed of 700 rpm for 0.2 h, then add 0.15 kg of single-walled carbon nanotubes for mixing at a stirring speed of 700 rpm for 1.1 h, then add 0.15 kg of sodium carboxymethyl cellulose, 0.72 kg of butadiene-styrene rubber emulsion with a solid content of 60%, and 9.7 kg of deionized water for homogenization at a stirring speed of 1350 rpm for 0.8 h to obtain a negative electrode slurry, which is coated on a copper foil and dried at a temperature of 100 ℃ to obtain a negative electrode sheet.

[0133] After the positive electrode sheet, the polyethylene non-woven membrane separator, and the negative electrode sheet are laminated and coiled, they are placed in an aluminum plastic shell, and liquid injection is performed. The injected LiPF6 electrolyte contains dimethyl carbonate with a concentration of 1.2 mol / L and an addition amount of 52±0.75 g, so that the positive electrode sheet, the separator, and the negative electrode sheet are completely infiltrated, and there is no flowable electrolyte. Then, the battery is packaged and formed to obtain the battery.

[0134] The batteries obtained in Examples 1-4 and the battery obtained in Comparative Example 1 are subjected to electrochemical performance testing, and the test results are shown in Table 1.

[0135] Table 1

[0136]

[0137] As can be seen from Table 1, the batteries obtained in Examples 1-4 are solid-state batteries, and compared with the solid-state battery obtained in Comparative Example 1, the rate performance is significantly better, the battery impedance is significantly reduced, and the cycle performance and temperature rise performance are significantly better, which shows that the lithium-rich agent is mixed in the positive electrode slurry after being coated by the porous solid-state electrolyte and coated to form the positive electrode sheet, and a porous solid-state electrolyte layer is formed on the surface of the negative electrode slurry of the negative electrode sheet. In combination with the injected electrolyte, the polyethylene non-woven membrane separator, the positive electrode sheet, and the negative electrode sheet completely absorb and accommodate the electrolyte. At this time, the electrolyte and the porous solid-state electrolyte form a close contact state between the positive electrode sheet, the separator, and the negative electrode sheet, and the electrolyte and the porous solid-state electrolyte provide a fast conduction channel for the conduction of lithium ions, effectively improving the rate and temperature rise performance of the battery.

[0138] The above examples only express several embodiments of the present application, and the description is more specific and detailed, but it cannot be understood as a limitation on the scope of the patent. It should be noted that for ordinary skilled persons in the art, without departing from the concept of the present application, a number of modifications and improvements can be made, which are within the scope of protection of the present application. Therefore, the protection scope of the patent of the present application should be subject to the appended claims.

Claims

1. A method of producing a solid-state battery, characterized by, The method comprises the following steps: obtaining a positive electrode sheet, a negative electrode sheet and a separator, wherein the positive electrode sheet is attached with a positive electrode slurry layer, the positive electrode slurry layer comprises a lithium-rich agent, a positive electrode active material, a porous solid-state electrolyte, a positive electrode binder and a conductive agent, the negative electrode sheet is attached with a negative electrode slurry layer, and the negative electrode slurry layer is coated with a porous solid-state electrolyte layer, wherein the porous solid-state electrolyte is porous lithium aluminum titanium phosphate, porous lithium lanthanum titanium oxide, porous lithium lanthanum zirconium oxide or porous polyphosphorus lithium sulfide, and the lithium-rich agent is lithium-rich lithium nickelate and / or lithium-rich lithium ironate; stacking the positive electrode sheet, the separator and the negative electrode sheet into a shell to arrange the positive electrode sheet and the negative electrode sheet to be separated by the separator and to be accommodated in a battery shell; injecting an electrolyte into the battery shell to perform a soaking solid-state treatment, so that the electrolyte is adsorbed on the positive electrode sheet, the separator and the porous solid-state electrolyte layer; packaging and forming the battery shell to obtain a solid-state battery; wherein the positive electrode slurry layer is obtained by coating a positive electrode slurry on the positive electrode sheet; the preparation method of the positive electrode slurry comprises the following steps: obtaining a porous solid-state electrolyte dispersion liquid and a lithium-rich agent; performing airflow dispersion treatment on the lithium-rich agent to make the lithium-rich agent in a dispersed state under the action of airflow; performing ultrasonic atomization coating operation on the lithium-rich agent in the dispersed state by using the porous solid-state electrolyte dispersion liquid, so that the porous solid-state electrolyte dispersion liquid is ultrasonic atomization dispersed and is brought to the surface of the lithium-rich agent by gas and coated on the lithium-rich agent to obtain coated lithium-rich agent; adding a positive electrode active material, a positive electrode binder and a conductive agent to the coated lithium-rich agent to perform mixing operation to obtain the positive electrode slurry.

2. The method of producing a solid-state battery according to claim 1, characterized by, The positive electrode slurry layer comprises the following components by mass: lithium-rich agent 3-5 parts; positive electrode active material 88-92 parts; porous solid-state electrolyte 6-10 parts; positive electrode binder 1-2 parts; conductive agent 0.5-1.5 parts.

3. The method of producing a solid-state battery according to claim 1 or 2, characterized by, The positive electrode active material is at least one of lithium manganeseate, lithium nickel cobalt manganeseate, lithium iron phosphate, lithium manganese iron phosphate, lithium cobaltate and lithium nickel cobalt aluminate; and / or The positive electrode binder is at least one of polyvinylidene fluoride, polyvinylpyrrolidone, polymethyl methacrylate, polyacrylonitrile and polytetrafluoroethylene.

4. The method of producing a solid-state battery according to claim 1, characterized by, The porous solid-state electrolyte layer comprises the following components by mass: porous solid-state electrolyte 55-70 parts; conductive agent 8-30 parts; negative electrode binder 8-25 parts.

5. The method of producing a solid-state battery according to claim 1, 2 or 4, characterized by, The conductive agent is at least one of carbon black, conductive graphite, carbon nanotube and graphene.

6. The method of producing a solid-state battery according to claim 1, 2, or 4, characterized by, The particle size D50 of the porous solid-state electrolyte is ≤270 nm.

7. The method of producing a solid-state battery according to claim 4, characterized by, The negative electrode binder is butadiene styrene rubber.

8. The method of producing a solid-state battery according to claim 1, characterized by, The thickness of the positive electrode slurry layer is 230-290 μm; and / or The face density of the positive electrode slurry layer is 450 g / m 2 ~ 550 g / m 2 ; and / or, The particle size D50 of the lithium-rich agent is 500 nm-1 μm; and / or The thickness of the porous solid-state electrolyte layer is 0.8-2 μm.

9. A solid state battery, characterized by The solid-state battery is prepared by the preparation method of the solid-state battery in any one of claims 1-8.

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