Battery cell, positive electrode sheet, positive electrode composite material and preparation method therefor, battery device and energy storage device

Abstract

The present application relates to the technical field of batteries, and particularly relates to a battery cell, a positive electrode sheet, a positive electrode composite material and a preparation method therefor, a battery device and an energy storage device. The battery cell comprises a positive electrode sheet, the positive electrode sheet comprises a positive electrode active layer, the positive electrode active layer comprises a positive electrode composite material, and the chemical formula of the positive electrode composite material comprises LiaM1 bM2 cM3 dM4 eOfSg, wherein M1 comprises one or more of Ti and Nb, M2, M3 and M4 respectively and independently comprise one or more of transition metals and Al, and M1, M2, M3 and M4 are respectively different metal elements; and a=1-2, b=0.1-1, 0<c≤0.5, 0<d≤0.5, 0<e≤0.5, f=0.1-2, and g=0.1-3. The solution of the present application can significantly increase both the capacity and the charge-discharge voltage of the battery.

Description

Battery cells, positive electrode sheets, positive electrode composite materials and their preparation methods, battery devices, energy storage devices Technical Field

[0001] This application relates to the field of battery technology, and in particular to battery cells, positive electrode sheets, positive electrode composite materials and their preparation methods, battery devices, and energy storage devices. Background Technology

[0002] In all-solid-state battery systems using sulfides as solid electrolytes, lithium-rich sulfide-based materials have become a research hotspot for cathode materials due to their good compatibility with the electrolyte and fewer side reactions. However, lithium-rich sulfide-based materials suffer from drawbacks such as low capacity and low charge / discharge voltage, which cannot meet the demand for high specific energy density cathode materials for all-solid-state batteries. Summary of the Invention

[0003] This application is made in view of the above-mentioned technical problems, and its purpose is to solve the problems of low capacity and low charge and discharge voltage of lithium-rich sulfur-based materials.

[0004] To achieve the above objectives, this application provides a battery cell, a positive electrode sheet, a positive electrode composite material and a preparation method thereof, a battery device, and an energy storage device.

[0005] The first aspect of this application provides a battery cell, including a positive electrode sheet, the positive electrode sheet including a positive electrode active layer, the positive electrode active layer including a positive electrode composite material, and the chemical formula of the positive electrode composite material including Li. a M 1 b M 2 c M 3 d M 4 e O f S g ;

[0006] Where M 1 Including one or more of Ti and Nb, M 2 M 3 M 4 Each independently includes one or more of transition metals and Al, and M 1 M 2 M 3 M 4 They are different metallic elements;

[0007] a=1~2, b=0.1~1, 0<c≤0.5, 0<d≤0.5, 0<e≤0.5, f=0.1~2, g=0.1~3.

[0008] The battery cells in this application embodiment have the characteristics of high capacity and high charging voltage, and can be charged at high voltage to provide high capacity. The principle may be that during battery cycling, sulfur anions in the positive electrode composite material participate in the electrochemical reaction first due to their low reaction voltage (a voltage plateau will appear in the capacity curve, i.e., the sulfur anion voltage plateau); while M 2 M 3 M 4 Metals with higher reaction voltages can participate in electrochemical reactions after the sulfur anion reaction, thus providing effective reversible capacity after the sulfur anion voltage plateau and improving the specific capacity of the material.

[0009] Meanwhile, after the sulfur anion reaction, the cathode composite material can also utilize M 2 M 3 M 4 The metal continues to undergo electrochemical reactions, meaning that after reaching the sulfur anion voltage plateau, it can continue to be charged and continue electrochemical reactions at a higher voltage, thus significantly improving the charge and discharge voltage.

[0010] The positive electrode composite material enables the battery cell to exhibit high capacity and high charge / discharge voltage.

[0011] In some implementations, a = 1.2–1.7, b = 0.3–0.7, c = 0.01–0.5, d = 0.01–0.5, e = 0.01–0.5, f = 0.5–1.5, and g = 1–2.

[0012] In some embodiments, the transition metal includes one or more of Ni, Co, and Mn. 2 M 3 M 4 The cathode composite material, which independently includes one or more transition metals such as Al, exhibits excellent rate performance when combined with transition metals such as Ni, Co, and Mn. Furthermore, Ni and Co can participate in compensating for delithiation caused by the reaction with sulfur anions, providing effective reversible capacity after the sulfur anion voltage plateau and improving the specific capacity of the material.

[0013] In some implementations, M 2 Including Ni, c = 0.05 to 0.5, optionally c = 0.1 to 0.4.

[0014] In some implementations, M 3 It includes one or more of Mn and Al, with d = 0.08 to 0.4, and optionally d = 0.13 to 0.27.

[0015] In some implementations, M 4Includes Co, e = 0.01 to 0.2, optionally e = 0.03 to 0.17.

[0016] By optimizing the elemental composition of cathode composite materials, the cathode composite materials can exhibit better specific capacity, charge / discharge voltage, and rate performance.

[0017] In some embodiments, the cathode composite material includes Li 1.5 Ti 0.5 Ni 0.25 Mn 0.2 Co 0.05 OS 1.5 Li 1.33 Ti 0.33 Ni 0.33 Mn 0.27 Co 0.07 O 1.33 S, Li 1.67 Ti 0.67 Ni 0.17 Mn 0.13 Co 0.03 O 0.67 S2, Li 1.5 Ti 0.5 Ni 0.17 Mn 0.17 Co 0.17 OS 1.5 One or more of these materials. These materials all have high specific capacity, high charge / discharge voltage, and good rate performance.

[0018] In some embodiments, the cathode composite material has a periodic layered structure; the space group of the cathode composite material is R-3m. Testing has shown that the cathode composite material of the embodiments of this application has a periodic layered structure with a space group of R-3m. This structure generally provides more lithium insertion sites, thereby increasing capacity; at the same time, it maintains good structural stability during charge and discharge, reducing capacity decay during cycling and extending battery life.

[0019] In some embodiments, diffraction peaks appear at positions of 2θ of 21°–22° and 24°–25° in the X-ray diffraction pattern of the cathode composite material. By observing the positions of the diffraction peaks in the X-ray diffraction pattern, it can be determined whether the cathode composite material of the present application is present.

[0020] In some embodiments, the relationship between the c-axis unit cell parameter c and the a-axis unit cell parameter a in the X-ray diffraction pattern of the cathode composite material satisfies: c > 4.9a; the value range of the a-axis unit cell parameter a is 2.8–3.0; the value range of the c-axis unit cell parameter c is 14.2–14.3; and the diffraction peak intensity I of the 003 crystal plane is... 003The diffraction peak intensity I of the 101 crystal plane 101 The ratio satisfies: 0.18 101 / I 003 <0.2. These unit cell parameters can be obtained from X-ray diffraction patterns. These parameters can be used to identify whether the cathode composite material of the embodiments of this application is present.

[0021] In some embodiments, the positive electrode active layer further includes a solid electrolyte, including a sulfide solid electrolyte. Adding a solid electrolyte to the positive electrode active layer can significantly improve the solid / solid interface properties between the solid electrolyte and the positive electrode sheet. Furthermore, the positive electrode composite material in this application embodiment is a sulfur-containing material, which has excellent compatibility with the sulfide solid electrolyte.

[0022] A second aspect of this application provides a positive electrode sheet, which includes a positive active layer. The positive active layer includes a positive composite material, and the chemical formula of the positive composite material includes Li. a M 1 b M 2 c M 3 d M 4 e O f S g ;

[0023] Where M 1 Including one or more of Ti and Nb, M 2 M 3 M 4 Each independently includes one or more of transition metals and Al, and M 1 M 2 M 3 M 4 They are different metallic elements;

[0024] a=1~2, b=0.1~1, 0<c≤0.5, 0<d≤0.5, 0<e≤0.5, f=0.1~2, g=0.1~3.

[0025] A third aspect of this application provides a positive electrode composite material, the chemical formula of which includes Li a M 1 b M 2 c M 3 d M 4 e O f S g ;

[0026] ​Where M 1 Including one or more of Ti and Nb, M 2 M 3 M 4 Each independently includes one or more of transition metals and Al, and M 1 M 2 M 3 M 4 They are different metallic elements;

[0027] a=1~2, b=0.1~1, 0<c≤0.5, 0<d≤0.5, 0<e≤0.5, f=0.1~2, g=0.1~3.

[0028] The fourth aspect of this application provides a method for preparing a positive electrode composite material, comprising the following steps:

[0029] Under a protective atmosphere, according to Li a M 1 b M 2 c M 3 d M 4 e O f S g The elemental ratios cause multi-component lithium metal oxides or their modified compounds, sulfur-based lithium compounds or their modified compounds to react.

[0030] Among them, sulfide-based lithium compounds contain M 1 Multi-component lithium metal oxides contain M 2 M 3 M 4 M 1 Including one or more of Ti and Nb, M 2 M 3 M 4 Each independently includes one or more of transition metals and Al, and M 1 M 2 M 3 M 4 They are different metallic elements;

[0031] a=1~2, b=0.1~1, 0<c≤0.5, 0<d≤0.5, 0<e≤0.5, f=0.1~2, g=0.1~3.

[0032] In some embodiments, the multi-component lithium metal oxide includes ternary materials. Optionally, the ternary material includes one or more of nickel-cobalt-manganese ternary materials and nickel-cobalt-aluminum ternary materials. These ternary materials all have high capacity, high rate performance, and high charge / discharge voltage. Reacting them with sulfur-based lithium compounds is beneficial for improving the capacity, rate performance, and charge / discharge voltage of the cathode composite material.

[0033] In some embodiments, the sulfur-based lithium compounds include Li₂TiS₃, Li₂NbS₃, Li₃NbS₄, and Li₂Ti 1-x3 Si x3 One or more of S3, wherein 0 < x3 ≤ 0.5. These sulfur-based compounds are all lithium-rich sulfur-based compounds, and their specific capacity, rate performance, and charge / discharge voltage can be effectively improved after reacting with multi-element lithium metal oxides. At the same time, these sulfur-based lithium compounds have good compatibility with sulfide solid electrolytes, which is beneficial to improving the solid / solid interface performance between the positive electrode and the solid electrolyte.

[0034] In some embodiments, the molar ratio between the multi-component lithium metal oxide or its modified compound and the sulfur-based lithium compound or its modified compound is 1:(0.5 to 2), optionally 1:(0.8 to 1.5). At suitable ratios, the multi-component lithium metal oxide or its modified compound and the sulfur-based lithium compound or its modified compound can successfully form the desired cathode composite material, thereby improving the specific capacity, charge / discharge voltage, and rate performance of the cathode composite material.

[0035] In some embodiments, the method of reacting a multi-component lithium metal oxide or its modified compound, a sulfur-based lithium compound or its modified compound, includes one or more of ball milling and sintering processes. During ball milling or sintering, the crystal structure of the raw materials is disrupted, and they can then recombine to form new compounds.

[0036] In some embodiments, the ball milling speed is 2000 rpm to 5000 rpm, and the ball milling time is 10 h to 30 h. Sufficient ball milling at high speed can effectively disrupt the crystal structure of the raw material and cause the elements to recombine, forming new compounds.

[0037] A fifth aspect of this application provides a battery device including a plurality of the aforementioned battery cells. The battery cells in this application embodiment are capable of being charged at high voltage and provide high capacity; therefore, applying these battery cells to a battery device helps to increase the capacity of the battery device.

[0038] A sixth aspect of this application provides an energy storage device, including a plurality of the above-described battery cells or a plurality of the above-described battery devices, wherein the battery cells or battery devices are used to store or provide electrical energy.

[0039] The aforementioned battery cells and battery devices are used to store or provide electrical energy for energy storage devices, which can increase the capacity of energy storage devices. Attached Figure Description

[0040] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0041] Figure 1 is an X-ray diffraction pattern of the positive electrode composite material in Example 1 of this application;

[0042] Figure 2 is a capacity curve diagram of Embodiment 1 and Comparative Example 1 of this application;

[0043] Figure 3 is a magnification curve diagram of Example 1 and Comparative Example 1 of this application;

[0044] Figure 4 is a schematic diagram of a battery cell according to an embodiment of this application;

[0045] Figure 5 is an exploded view of a battery cell according to an embodiment of this application, as shown in Figure 4. Detailed Implementation

[0046] The embodiments of this application are hereby disclosed in detail with appropriate reference to the accompanying drawings. However, unnecessary detailed descriptions may be omitted. For example, detailed descriptions of well-known matters and repetitive descriptions of actually identical structures may be omitted. This is to avoid making the following description unnecessarily lengthy and to facilitate understanding by those skilled in the art. Furthermore, the accompanying drawings and the following description are provided to enable those skilled in the art to fully understand this application and are not intended to limit the subject matter of the claims.

[0047] The "range" disclosed in this application is defined by a lower limit and an upper limit. A given range is defined by selecting a lower limit and an upper limit, which define the boundaries of a particular range. Ranges defined in this way can include or exclude endpoints and can be arbitrarily combined; that is, any lower limit can be combined with any upper limit to form a range. For example, if ranges of 60–120 and 80–110 are listed for a specific parameter, it is understood that ranges of 60–110 and 80–120 are also expected. Furthermore, if minimum range values ​​of 1 and 2 are listed, and if maximum range values ​​of 3, 4, and 5 are listed, then the following ranges are all expected: 1–3, 1–4, 1–5, 2–3, 2–4, and 2–5. In this application, unless otherwise stated, the numerical range "a–b" represents a shortened representation of any combination of real numbers between a and b, where a and b are real numbers. For example, the numerical range "0~5" indicates that all real numbers between "0~5" have been listed in this article; "0~5" is simply a shortened representation of these numerical combinations. Furthermore, when a parameter is stated as an integer ≥2, it is equivalent to disclosing that the parameter is, for example, an integer such as 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0048] Unless otherwise specified, all embodiments and optional embodiments of this application can be combined to form new technical solutions.

[0049] Unless otherwise specified, all technical features and optional technical features of this application may be combined to form new technical solutions.

[0050] Unless otherwise specified, all steps in this application may be performed sequentially or randomly, preferably sequentially. For example, the method includes steps (a) and (b), indicating that the method may include steps (a) and (b) performed sequentially, or it may include steps (b) and (a) performed sequentially. For example, the mention that the method may also include step (c) indicates that step (c) may be added to the method in any order. For example, the method may include steps (a), (b), and (c), or it may include steps (a), (c), and (b), or it may include steps (c), (a), and (b), etc.

[0051] Unless otherwise specified, the terms "comprising" and "including" as used in this application can be open-ended or closed-ended. For example, "comprising" and "including" can mean that other components not listed may also be included, or that only the listed components may be included.

[0052] Unless otherwise specified, the term "or" is inclusive in this application. For example, the phrase "A or B" means "A, B, or both A and B". More specifically, the condition "A or B" is satisfied by any of the following conditions: A is true (or exists) and B is false (or does not exist); A is false (or does not exist) and B is true (or exists); or both A and B are true (or exist).

[0053] In all-solid-state battery systems using sulfides as solid electrolytes, the cathode material undergoes significant side reactions with the sulfide electrolyte, leading to severe structural degradation at the solid-solid interface between the cathode and electrolyte, which severely impacts battery performance. Furthermore, because sulfides themselves have low charge / discharge voltages, this situation is particularly pronounced at high voltages.

[0054] Lithium-rich sulfide-based materials (mainly lithium titanium sulfide Li₂TiS₃) exhibit well-matched charge-discharge voltages with sulfide electrolytes. Furthermore, since both lithium-rich sulfide-based materials and sulfide electrolytes are sulfide-based, they exhibit little or no side reactions. Simultaneously, lithium-rich sulfide-based materials possess strong TM-S (TM being a transition metal) chemical bond energies, which can mitigate structural problems such as transition metal migration and anion escape. Given these advantages, lithium-rich sulfide-based materials have significant potential as cathode materials in all-solid-state battery systems using sulfides as solid-state electrolytes, becoming a research hotspot in this system. For example, some studies have used lithium sulfide, niobium sulfide, and titanium sulfide as raw materials for mechanical grinding to prepare cubic rock-salt-type crystalline lithium titanium sulfide and lithium niobium sulfide cathode materials, which exhibit excellent compatibility with sulfide electrolytes.

[0055] However, lithium-rich sulfur-based materials have drawbacks such as low capacity, low charge and discharge voltage, and poor rate performance, which cannot meet people's demand for high specific energy density all-solid-state battery cathode materials.

[0056] Based on this, embodiments of this application provide a positive electrode composite material, which is a new compound formed by lithium-rich sulfur-based compounds and multi-component lithium metal oxides. The multi-component lithium metal oxides can be used to compensate for the capacity, improve the specific capacity of the material, and also improve the charge and discharge voltage of the material; in some cases, the rate performance of the material can also be improved.

[0057] The positive electrode composite material of this application embodiment can be applied to positive electrode sheets, and further to battery cells, especially solid-state battery cells using sulfides as solid electrolytes. These battery cells exhibit high capacity, high rate performance, and high charge / discharge voltage. The battery cell can be used in battery devices and energy storage devices.

[0058] The battery cell in this embodiment includes a positive electrode, a negative electrode, and a solid electrolyte, with the solid electrolyte disposed between the positive and negative electrodes. During battery charging and discharging, active ions repeatedly insert and extract between the positive and negative electrodes. The electrolyte acts as a conductor of ions between the positive and negative electrodes.

[0059] [Positive electrode plate]

[0060] The positive electrode sheet in this application embodiment includes a positive electrode active layer, which comprises a positive electrode composite material. The chemical formula of the positive electrode composite material includes Li. a M 1 b M 2 c M 3 d M 4 e O f S g ;

[0061] Where M 1 Including one or more of Ti and Nb, M 2 M 3 M 4 Each independently includes one or more of transition metals and Al, and M 1 M 2 M 3 M 4 They are different metallic elements;

[0062] a=1~2, b=0.1~1, 0<c≤0.5, 0<d≤0.5, 0<e≤0.5, f=0.1~2, g=0.1~3.

[0063] Inductively coupled plasma optical emission spectrometry (ICP-OES) can be used to detect the positive electrode active layer, obtain the types and proportions of each element, and thus determine the chemical formula of the positive electrode composite material.

[0064] Practice shows that the positive electrode provided in this application embodiment has high specific capacity and high charging voltage. The principle may be that during battery cycling, the sulfur anions in the positive electrode composite material participate in the electrochemical reaction first due to their low reaction voltage (a voltage plateau will appear in the capacity curve, i.e., the sulfur anion voltage plateau); while M 2 M 3 M 4 Metals with higher reaction voltages can participate in electrochemical reactions after the sulfur anion reaction, thus providing effective reversible capacity after the sulfur anion voltage plateau and improving the specific capacity of the material.

[0065] Meanwhile, after the sulfur anion reaction, the cathode composite material can also utilize M 2 M 3 M 4 The metal continues to undergo electrochemical reactions, meaning that after reaching the sulfur anion voltage plateau, it can continue to be charged and continue electrochemical reactions at a higher voltage, thus significantly improving the charge and discharge voltage.

[0066] In some implementations, a = 1 to 2, and optionally a = 1.2 to 1.7. For example, a can be any one of 1, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2, or a range between any two.

[0067] In some implementations, b = 0.1 to 1, and optionally b = 0.3 to 0.7. For example, b can be any one of 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, or a range between any two.

[0068] In some implementations, 0 < c ≤ 0.5, and optionally c = 0.01 to 0.5. For example, c can be any one or any two of 0.01, 0.1, 0.2, 0.3, 0.4, 0.5.

[0069] In some implementations, 0 < d ≤ 0.5, and optionally d = 0.01 to 0.5. For example, d can be any one of 0.01, 0.1, 0.2, 0.3, 0.4, 0.5 or a range between any two of them.

[0070] In some implementations, 0 < e ≤ 0.5, and optionally e = 0.01 to 0.5. For example, e can be any one of 0.01, 0.1, 0.2, 0.3, 0.4, 0.5 or a range between any two of them.

[0071] In some embodiments, the transition metal includes one or more of Ni, Co, and Mn. 2 M 3 M 4 The cathode composite material, which independently includes one or more transition metals such as Al, exhibits excellent rate performance when combined with transition metals such as Ni, Co, and Mn. Furthermore, Ni and Co can participate in compensating for delithiation caused by the reaction with sulfur anions, providing effective reversible capacity after the sulfur anion voltage plateau and improving the specific capacity of the material.

[0072] In some implementations, M 2 Including Ni, c = 0.05 to 0.5, optionally c = 0.1 to 0.4, and even more optionally c = 0.17 to 0.33.

[0073] In some implementations, M 3 Includes Mn, d = 0.08 to 0.4, optionally d = 0.13 to 0.27.

[0074] In some implementations, M 4 Includes Co, e = 0.01 to 0.1, optionally e = 0.03 to 0.07.

[0075] In some implementations, f = 0.1 to 2, and optionally f = 0.5 to 1.5. For example, f is any one or a range between any two of 0.1, 0.2, 0.4, 0.5, 0.6, 0.8, 1, 1.2, 1.4, 1.5, 1.6, 1.8, 2.

[0076] In some implementations, g = 0.1 to 3, and optionally g = 1 to 2. For example, g is any one or a range between any two of 0.1, 0.2, 0.4, 0.5, 0.6, 0.8, 1, 1.2, 1.4, 1.5, 1.6, 1.8, 2, 2.5, and 3.

[0077] By optimizing the elemental composition of cathode composite materials, the cathode composite materials can exhibit better specific capacity, charging voltage, and rate performance.

[0078] In some embodiments, the cathode composite material includes Li 1.5 Ti 0.5 Ni 0.25 Mn 0.2 Co 0.05 OS 1.5 Li 1.33 Ti 0.33 Ni 0.33 Mn 0.27 Co 0.07 O 1.33 S, Li 1.67 Ti 0.67 Ni 0.17 Mn 0.13 Co 0.03 O 0.67 S2, Li 1.5 Ti 0.5 Ni 0.17 Mn 0.17 Co 0.17 OS 1.5 One or more of these materials. These materials all have high specific capacity, high charge / discharge voltage, and good rate performance.

[0079] In some embodiments, the cathode composite material has a periodic layered structure; the space group of the cathode composite material is R-3m. The structural characteristic of the periodic layered structure of the cathode composite material is that metal ions (metal ions other than lithium ions) and lithium ions alternately occupy octahedral positions, forming a periodic layered arrangement. X-ray diffraction (XRD) analysis can be performed on the material to obtain X-ray diffraction patterns. From the X-ray diffraction patterns, crystal structure information of the material can be obtained, such as interplanar spacing and lattice parameters, thereby determining whether the material has a layered structure. By indexing the crystal plane indices of the diffraction peaks and combining them with the chemical formula and possible symmetries, the possible space group can be determined. Testing shows that the cathode composite material of the embodiments of this application has a periodic layered structure with a space group of R-3m. This structure is generally advantageous in providing more lithium intercalation sites, thereby increasing capacity; at the same time, it can maintain good structural stability during charge and discharge, reducing capacity decay during cycling and extending battery life.

[0080] In some embodiments, diffraction peaks appear at positions of 2θ of 21°–22° and 24°–25° in the X-ray diffraction pattern of the cathode composite material. By observing the positions of the diffraction peaks in the X-ray diffraction pattern, it can be determined whether the cathode composite material of the present application is present.

[0081] In some embodiments, the relationship between the c-axis unit cell parameter c and the a-axis unit cell parameter a in the X-ray diffraction pattern of the cathode composite material satisfies: c > 4.9a; the value range of the a-axis unit cell parameter a is 2.8 to 3.0; the value range of the c-axis unit cell parameter c is 14.2 to 14.3; and the diffraction peak intensity I of the 003 crystal plane is... 003 The diffraction peak intensity I of the 101 crystal plane 101 The ratio satisfies: 0.18 101 / I 003 <0.2. These unit cell parameters can be obtained from X-ray diffraction patterns. These parameters can be used to identify whether the cathode composite material of the embodiments of this application is present.

[0082] In some embodiments, the mass content of the positive electrode composite material in the positive electrode active layer may include, but is not limited to, 60% to 98%, or 60% to 90%, for example, any one of 60%, 70%, 75%, 80%, 85%, 90%, 92%, 94%, 96%, 98%, or any range between two.

[0083] This positive electrode composite material can be prepared by the following method:

[0084] Under a protective atmosphere, according to Li a M 1 b M 2 ​c M 3 d M 4 e O f S g The elemental ratios cause multi-component lithium metal oxides or their modified compounds, sulfur-based lithium compounds or their modified compounds to react.

[0085] Among them, sulfide-based lithium compounds contain M 1 Multi-component lithium metal oxides contain M 2 M 3 M 4 M 1 Including one or more of Ti and Nb, M 2 M 3 M 4 Each independently includes one or more of transition metals and Al, and M 1 M 2 M 3 M 4 They are different metallic elements.

[0086] The term "multi-element lithium metal oxide" refers to a metal oxide that contains multiple (at least two, optionally three or more) other metal elements besides lithium.

[0087] Lithium-based metal oxides or their modified compounds, and sulfur-based lithium compounds or their modified compounds, can react to generate Li. a M 1 b M 2 c M 3 d M 4 e O f S g When this material is applied to batteries, during battery cycling, the sulfur anions derived from sulfur-based lithium compounds participate in the electrochemical reaction first due to their low reaction voltage (a voltage plateau appears in the capacity curve, namely the sulfur anion voltage plateau). Meanwhile, metals other than lithium derived from multi-element lithium metal oxides have higher reaction voltages and can participate in the electrochemical reaction after the sulfur anion reaction. This provides effective reversible capacity after the sulfur anion voltage plateau, improving the specific capacity of the material. At the same time, after the sulfur anion reaction, the cathode composite material can continue to undergo electrochemical reactions using metals derived from multi-element lithium metal oxides. That is, after reaching the sulfur anion voltage plateau, it can continue to be charged and continue electrochemical reactions at a higher voltage, thus significantly improving the charge and discharge voltage.

[0088] In some embodiments, the multi-component lithium metal oxide includes a ternary material. Optionally, the ternary material includes one or more of nickel-cobalt-manganese ternary materials and nickel-cobalt-aluminum ternary materials.

[0089] Among them, the nickel-cobalt-manganese ternary material is lithium nickel-cobalt-manganese oxide, whose chemical formula can be LiNi x1 Co y1 Mn z1 O2, where x1>0, y1>0, z1>0, x1+y1+z1=1.

[0090] Optionally, x1 = 0.3 to 0.8, y1 = 0.1 to 0.4, and z1 = 0.1 to 0.3. For example, x1 is a point value between any one or any two of 0.3, 0.4, 0.5, 0.6, 0.7, and 0.8; y1 is a point value between any one or any two of 0.1, 0.2, 0.3, and 0.4; and z1 is a point value between any one or any two of 0.1, 0.2, and 0.3.

[0091] Exemplary nickel-cobalt-manganese ternary materials include LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2(NCM111), LiNi 0.4 Co 0.4 Mn 0.2 O2(NCM442), LiNi 0.5 Co 0.2 Mn 0.3 O2(NCM523), LiNi 0.6 Co 0.2 Mn 0.2 O2(NCM622), LiNi 0.8 Co 0.1 Mn 0.1 O2(NCM811), LiNi 0.5 Co 0.4 Mn 0.1 O2(NCM541), LiNi 0.5 Co 0.1 Mn 0.4 One or more of O2 (NCM514).

[0092] Nickel-cobalt-aluminum ternary materials, namely lithium nickel-cobalt-aluminum oxide, can have the chemical formula LiNi. x2 Co y2 Al z2 O2, where x2>0, y2>0, z2>0, x2+y2+z2=1.

[0093] Optionally, x² = 0.3 to 0.8, y² = 0.1 to 0.4, and z² = 0.1 to 0.3. For example, x² can be any one of 0.3, 0.4, 0.5, 0.6, 0.7, and 0.8, or any two of them; y² can be any one of 0.1, 0.2, 0.3, and 0.4, or any two of them; and z² can be any one of 0.1, 0.2, and 0.3, or any two of them.

[0094] Exemplary nickel-cobalt-aluminum ternary materials include LiNi 0.8 Co 0.15 Al 0.05 O2, LiNi 1 / 3 Co 1 / 3 Al 1 / 3 O2(NCA111), LiNi 0.5 Co 0.2 Al 0.3 O2(NCA523), LiNi 0.6 Co 0.2 Al 0.2 One or more of O2 (NCA622).

[0095] These ternary materials all have high capacity, high rate performance, and high charge / discharge voltage. Reacting them with sulfur-based lithium compounds is beneficial to improving the capacity, rate performance, and charge / discharge voltage of the cathode composite material.

[0096] Modified compounds of multi-component lithium metal oxides are materials that have undergone modification treatment of multi-component lithium metal oxides. The modification treatment methods include one or more of the following: element (metal element or non-metal element) doping, surface coating, and surface modification.

[0097] In some embodiments, the sulfur-based lithium compounds include Li₂TiS₃, Li₂NbS₃, Li₃NbS₄, and Li₂Ti 1-x3 Si x3 One or more of S3, where 0 < x3 ≤ 0.5, for example, x3 = any one or any two of 0.01, 0.05, 0.1, 0.2, 0.3, 0.4, 0.5. These sulfur-based compounds are all lithium-rich sulfur-based compounds [referring to a sulfur-based compound with a high lithium content, usually having a high Li / M (M represents a metal other than lithium) molar ratio, and in some cases, the molar ratio Li / M > 1], which can effectively improve specific capacity, rate performance, and charging voltage after reacting with multi-element lithium metal oxides. At the same time, these sulfur-based lithium compounds have good compatibility with sulfide solid electrolytes, which is beneficial to improving the solid / solid interface performance between the positive electrode and the solid electrolyte.

[0098] Similarly, modified compounds of sulfur-based lithium compounds are materials that have been modified by sulfur-based lithium compounds. The modification methods include one or more of the following: element (metal or non-metal element) doping, surface coating, and surface modification.

[0099] In some embodiments, the molar ratio between a multi-component lithium metal oxide or its modified compound and a sulfur-based lithium compound or its modified compound is 1:(0.5–2), optionally 1:(0.8–1.5). For example, this molar ratio can be any one or any combination of 1:0.5, 1:0.8, 1:1, 1:1.2, 1:1.5, 1:1.8, and 1:2. At suitable ratios, the multi-component lithium metal oxide or its modified compound, together with the sulfur-based lithium compound or its modified compound, can successfully form the desired cathode composite material and improve the specific capacity, charge / discharge voltage, and rate performance of the cathode composite material.

[0100] In some embodiments, the method of reacting a multi-component lithium metal oxide or its modified compound, a sulfur-based lithium compound or its modified compound includes one or more of ball milling and sintering processes.

[0101] Ball milling involves mixing a multi-component lithium metal oxide or its modified compound with a sulfur-based lithium compound or its modified compound, and then milling the mixture in a ball mill. Sintering involves mixing a multi-component lithium metal oxide or its modified compound with a sulfur-based lithium compound or its modified compound, and then sintering the mixture. During ball milling or sintering, the crystal structure of the raw materials is disrupted, allowing them to recombine and form new compounds.

[0102] In some embodiments, the ball milling speed is 2000 rpm to 5000 rpm, optionally 2000 rpm to 3000 rpm, for example, any one or a value between 2000 rpm, 2500 rpm, 3000 rpm, 3500 rpm, 4000 rpm, and 4500 rpm. The ball milling time is 10 h to 30 h, for example, any one or a value between 10 h, 15 h, 20 h, 25 h, and 30 h. The ball milling direction includes one or more of unidirectional rotation and forward and reverse rotation, wherein unidirectional rotation refers to rotation in the same direction; forward and reverse rotation refers to rotation in the forward direction for a certain period of time, followed by rotation in the reverse direction, or alternating between forward and reverse rotation.

[0103] High-speed ball milling for a sufficient time can effectively disrupt the crystal structure of the raw materials and cause the elements to recombine, forming new compounds.

[0104] In some embodiments, the grinding jar used in the ball milling process is made of one or more of the following materials: stainless steel, corundum (alumina), zirconium oxide, agate, and polytetrafluoroethylene.

[0105] The ball mills used in the ball milling process include one or more of the following: planetary ball mills, mixing ball mills, vibratory ball mills, and horizontal rolling ball mills.

[0106] The particle size of multi-component lithium metal oxides or their modified compounds is 2–40 μm, for example, any one or a value between any two of 2 μm, 5 μm, 10 μm, 15 μm, 20 μm, 25 μm, 30 μm, 35 μm, and 40 μm. The particle size of sulfur-based lithium compounds or their modified compounds is 1–10 μm, for example, any one or a value between any two of 1 μm, 2 μm, 4 μm, 6 μm, 8 μm, and 10 μm. Using small-particle-size raw materials not only facilitates uniform mixing between different raw materials but also helps to improve ball milling efficiency.

[0107] The particle size of the cathode composite material obtained after ball milling is 1 to 20 μm, for example, any one or any two of 1 μm, 5 μm, 10 μm, 15 μm, and 20 μm.

[0108] In some embodiments, a grinding process is included before ball milling. The grinding process takes 10 to 30 minutes, for example, any one or any two of 10, 15, 20, 25, and 30 minutes. Pre-treating the raw materials by grinding ensures that the materials are mixed evenly.

[0109] In some embodiments, the ball milling and grinding processes are performed under a protective atmosphere, such as one or more of nitrogen, argon, and helium. Performing ball milling and grinding processes under a protective atmosphere can prevent the raw materials from oxidizing or reacting with moisture in the air during the process, maintain the chemical stability of the raw materials, and successfully obtain the desired cathode composite material.

[0110] In some embodiments, the positive electrode active layer also includes a conductive agent, a binder, and a solid electrolyte.

[0111] The conductive agent includes one or more of the following: carbon fiber (e.g., vapor-grown carbon fiber VGCF), acetylene black, conductive carbon black (SP), Ketjen black, carbon dots, carbon nanotubes, and graphene.

[0112] The adhesive may include one or more of the following: polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), PVDF-tetrafluoroethylene-propylene terpolymer, PVDF-hexafluoropropylene-tetrafluoroethylene terpolymer, tetrafluoroethylene-hexafluoropropylene copolymer, fluorinated acrylate resin, polyamide (PA), polyacrylonitrile (PAN), polyacrylate, polyethylene ether, polymethyl methacrylate (PMMA), polyhexafluoropropylene, and styrene-butadiene rubber (SBR).

[0113] The mass content of binder and conductive agent in the positive electrode active layer can be independently, including but not limited to 0.5% to 10%, or 1% to 10%, for example, any one of 0.5%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, or any range between the two.

[0114] Solid electrolytes include sulfide solid electrolytes, such as Li6PS5Cl, Li6PS5Br, Li6PS5I, Li3PS4, and Li7P3S. 11 Li 10 GeP2S 12 Li 3.25 Ge 0.25 P 0.75 S4, Li 9.54 Si 1.74 P 1.44 S 11.7 Cl 0.3 The cathode material comprises one or more of the following: Li₂S-P₂S₅-LiCl, Li₂S-SiS₂, Li₂S-P₂S₅, LiI-Li₂S-SiS₂, LiI-Li₂S-P₂S₅, LiI-Li₂S-P₂O₅, LiI-Li₂S-B₂S₃, LiI-Li₃PO₄-P₂S₅, Li₃PO₄-Li₂S-Si₂S, Li₃PO₄-Li₂S-SiS₂, and LiPO₄-Li₂S-SiS. Adding a solid electrolyte to the positive electrode active layer can significantly improve the solid / solid interface performance between the solid electrolyte and the positive electrode. Furthermore, the positive electrode composite material in this embodiment is a sulfur-containing material, exhibiting excellent compatibility with sulfide solid electrolytes.

[0115] Understandably, depending on actual needs, the solid electrolyte in the positive electrode active layer may also include one or more of oxide-based solid electrolytes and organic solid electrolytes. Exemplary oxide-based solid electrolytes include one or more of perovskite solid electrolytes, lithium superion conductor solid electrolytes (LISICON), and lithium lanthanum zirconium oxide solid electrolytes (LLZO). Exemplary organic solid electrolytes include polyethylene oxide (PEO).

[0116] In the positive electrode active layer, the mass content of solid electrolyte can be 15% to 35%, for example, any one of 15%, 20%, 30%, 35% or any range between two.

[0117] In some embodiments, the positive electrode active layer may optionally include additives, such as additives that can improve certain properties of the positive electrode sheet, such as additives with lithium replenishment effects.

[0118] In some embodiments, the positive electrode may optionally include a positive current collector. The positive current collector includes two surfaces opposite each other in its own thickness direction, and the positive active layer may be disposed on either or both of the opposite surfaces of the positive current collector.

[0119] The positive current collector includes one or more of a metal foil and a composite current collector. For example, aluminum foil can be used as the metal foil. The composite current collector may include a polymer material substrate and a metal layer formed on at least one surface of the polymer material substrate. The composite current collector can be formed by forming a metal material (aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer material substrate [such as polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.].

[0120] In some implementations, the positive electrode sheet can be prepared in the following manner:

[0121] The components used to prepare the positive electrode sheet, such as positive electrode composite material, conductive agent, binder, solid electrolyte and any other components, are mixed, formed into a film, and pressed to obtain the positive electrode sheet. The positive electrode sheet thus prepared is usually also called a positive electrode film.

[0122] Alternatively, the components used to prepare the positive electrode sheet, such as positive electrode composite material, conductive agent, binder, solid electrolyte and any other components, can be dispersed in a solvent (e.g., N-methylpyrrolidone) to form a positive electrode slurry; the positive electrode slurry can be coated on the positive electrode current collector, and after drying, cold pressing and other processes, the positive electrode sheet can be obtained.

[0123] The thickness of the positive electrode film or positive electrode active layer can be set to 30μm to 80μm, optionally 50μm to 60μm, for example, any one of 30μm, 40μm, 50μm, 60μm, 70μm, 80μm or any range between two.

[0124] [Negative electrode plate]

[0125] The battery cell in this application embodiment includes a negative electrode sheet, which includes lithium or a lithium alloy, or includes a negative current collector and a negative active layer disposed on at least one side of the negative current collector. The negative active layer includes a negative active material, a conductive agent, and a binder.

[0126] In some embodiments, the lithium alloy includes one or more of lithium-indium alloy, lithium-silicon alloy, lithium-aluminum alloy, and lithium-magnesium alloy. The molar ratio of lithium to other elements in the lithium alloy can be set as needed, for example, it can be set to 1:(2-5), such as any one of 1:2, 1:3, 1:4, 1:5, or any range between two. Lithium and lithium alloy can be used alone as the negative electrode, or lithium and lithium alloy can be disposed on at least one side of the negative electrode current collector. In some embodiments, the negative electrode active material includes one or more of graphite (artificial graphite, natural graphite), soft carbon, hard carbon, silicon-based materials, tin-based materials, and titanium-based materials. Silicon-based materials may include one or more of elemental silicon, silicon oxide compounds, silicon-carbon composites, silicon-nitrogen composites, and silicon alloys. Tin-based materials may include one or more of elemental tin, tin oxide compounds, and tin alloys. Titanium-based materials may include lithium titanate. It is understood that this application is not limited to these materials, and other materials that can be used as battery negative electrode active materials may also be used. These negative electrode active materials may be used alone or in combination of two or more.

[0127] The mass content of the negative electrode active material in the negative electrode active layer can range from 70% to 98%, or even 90% to 98%, for example, any one of the values ​​of 70%, 75%, 80%, 85%, 90%, 92%, 94%, 96%, or 98%, or any range between two of these values. A high content of negative electrode active material can provide high energy density for the battery.

[0128] In some embodiments, the binder may include one or more of SBR (styrene-butadiene rubber), PAAS (sodium polyacrylate), PAM (polyacrylamide), PVA (polyvinyl alcohol), SA (sodium alginate), PMAA (polymethacrylic acid), and CMCS (carboxymethyl chitosan). The mass content of the binder in the negative electrode active layer may be 0.1% to 10%, for example, any one or a range between 0.1%, 0.5%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, and 10%.

[0129] In some embodiments, the conductive agent may include one or more of acetylene black, conductive carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers. The mass content of the conductive agent in the negative electrode active layer includes 0.5% to 10%, for example, any one of 0.5%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, and 10%, or a range between any two.

[0130] In some embodiments, the negative electrode also includes a solid electrolyte dispersed in the lithium alloy or dispersed in the negative electrode active layer.

[0131] The solid electrolyte in the negative electrode includes sulfide solid electrolytes, such as Li6PS5Cl, Li6PS5Br, Li6PS5I, Li3PS4, and Li7P3S. 11 Li 10 GeP2S 12 Li 3.25 Ge 0.25 P 0.75 S4, Li 9.54 Si 1.74 P 1.44 S 11.7 Cl 0.3 One or more of the following are suitable: Li₂S-P₂S₅-LiCl, Li₂S-SiS₂, Li₂S-P₂S₅, LiI-Li₂S-SiS₂, LiI-Li₂S-P₂S₅, LiI-Li₂S-P₂O₅, LiI-Li₂S-B₂S₃, LiI-Li₃PO₄-P₂S₅, Li₃PO₄-Li₂S-Si₂S, Li₃PO₄-Li₂S-SiS₂, and LiPO₄-Li₂S-SiS. Adding a solid electrolyte to the negative electrode can significantly improve the interfacial properties between the solid electrolyte and the negative electrode.

[0132] Understandably, depending on actual needs, the solid electrolyte in the negative electrode may also include one or more of oxide-based solid electrolytes and organic solid electrolytes. Exemplary oxide-based solid electrolytes include one or more of perovskite solid electrolytes, lithium superion conductor solid electrolytes (LISICON), and lithium lanthanum zirconium oxide solid electrolytes (LLZO). Exemplary organic solid electrolytes include polyethylene oxide (PEO).

[0133] In the negative electrode sheet, the mass ratio of the negative electrode active material to the solid electrolyte can be set as needed. For example, it can be set to (1~5):1, such as any one of the following values ​​or any range between 1:1, 2:1, 3:1, 4:1, 5:1.

[0134] In some embodiments, the negative electrode active layer may optionally include other additives, such as thickeners, like carboxymethyl cellulose (CMC), sodium carboxymethyl cellulose (CMC-Na), etc.

[0135] In some embodiments, the negative electrode current collector has two surfaces opposite each other in its own thickness direction, and the negative electrode active layer is disposed on either or both of the two opposite surfaces of the negative electrode current collector. The negative electrode current collector includes one or more of metal foil and composite current collector. For example, copper foil can be used as the metal foil. The composite current collector may include a polymer material substrate and a metal layer formed on at least one surface of the polymer material substrate. The composite current collector can be formed by forming a metal material (copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer material substrate [such as polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.].

[0136] In some embodiments, when the negative electrode sheet includes a negative electrode current collector and a negative electrode active layer disposed on at least one side of the negative electrode current collector, the negative electrode sheet can be prepared in the following manner:

[0137] The components used to prepare the negative electrode sheet, such as negative electrode active material, solid electrolyte, binder, and conductive agent (and may also include any other components), are dispersed in a solvent (e.g., water) to form a negative electrode slurry. The negative electrode slurry is coated on at least one side of the negative electrode current collector, and after drying, cold pressing and other processes, the negative electrode sheet can be obtained.

[0138] When the negative electrode includes a lithium alloy, the negative electrode can be prepared in the following way:

[0139] Lithium alloys can be formed into strips or bars to serve as negative electrode sheets. Alternatively, lithium alloys can be rolled together with negative electrode current collectors to form negative electrode sheets.

[0140] [Electrolytes]

[0141] In the battery cell of this application embodiment, the electrolyte is a solid electrolyte, which is disposed between the positive electrode and the negative electrode and is in contact with the positive electrode and the negative electrode.

[0142] In some embodiments, the solid electrolyte includes a sulfide solid electrolyte, which includes Li6PS5Cl, Li6PS5Br, Li6PS5I, Li3PS4, and Li7P3S. 11 Li 10 GeP2S 12 Li 3.25 Ge 0.25 P 0.75 S4, Li 9.54 Si 1.74 P 1.44 S 11.7 Cl 0.3One or more of the following: Li₂S-P₂S₅-LiCl, Li₂S-SiS₂, Li₂S-P₂S₅, LiI-Li₂S-SiS₂, LiI-Li₂S-P₂S₅, LiI-Li₂S-P₂O₅, LiI-Li₂S-B₂S₃, LiI-Li₃PO₄-P₂S₅, Li₃PO₄-Li₂S-Si₂S, Li₃PO₄-Li₂S-SiS₂, and LiPO₄-Li₂S-SiS. Sulfide solid electrolytes exhibit higher ionic conductivity, a wider electrochemical window, and good compatibility with the negative electrode compared to other types of solid electrolytes, making them suitable for preparing high-performance battery cells.

[0143] Understandably, depending on actual needs, solid electrolytes may also include one or more of oxide-based solid electrolytes and organic solid electrolytes. Exemplary oxide-based solid electrolytes include one or more of perovskite solid electrolytes, lithium superion conductor solid electrolytes (LISICON), and lithium lanthanum zirconium oxide solid electrolytes (LLZO). Exemplary organic solid electrolytes include polyethylene oxide (PEO).

[0144] [Outer Packaging]

[0145] A single battery cell may include an outer packaging that can be used to encapsulate the positive electrode, negative electrode, and electrolyte.

[0146] The outer packaging can be a hard shell, such as a hard plastic shell, aluminum shell, or steel shell; or it can be a soft package, such as a pouch. The material of the soft package can be plastic, such as polypropylene, polybutylene terephthalate, and polybutylene succinate.

[0147] The outer packaging can be cylindrical, square, or any other shape. For example, Figure 4 shows a battery cell with a square outer packaging structure as an example.

[0148] Referring to Figure 5, the outer packaging may include a housing 01 and a cover plate 02. The housing 01 may include a base plate and side plates connected to the base plate, the base plate and side plates forming a receiving cavity. The housing 01 has an opening communicating with the receiving cavity, and the cover plate 02 can be placed over the opening to close the receiving cavity. A positive electrode, a negative electrode, and a separator can be formed into an electrode assembly 03 via a winding process or a stacking process. One or more electrode assemblies 03 are encapsulated within the receiving cavity. Electrolyte is immersed in the electrode assembly 03.

[0149] [Battery cell]

[0150] In this embodiment, the battery cell can be a rechargeable battery, which refers to a battery cell that can be recharged after discharge to activate the active materials and continue to be used. Optionally, the battery cell in this embodiment can be an all-solid-state lithium metal battery.

[0151] In the battery cell of this application embodiment, the positive electrode sheet includes a positive electrode composite material with a specific structure. This positive electrode composite material has the advantages of high specific capacity and high charging voltage. Therefore, the battery cell also exhibits the characteristics of high capacity and high charging voltage, and can be charged at high voltage to provide high capacity.

[0152] A battery cell can be assembled as follows: the positive electrode and the negative electrode are respectively installed at both ends of the solid electrolyte, and pressure is applied to make the positive electrode and the negative electrode in close contact with the solid electrolyte.

[0153] [Battery Device]

[0154] This application provides a battery apparatus including multiple battery cells. Specifically, the battery apparatus mentioned in the embodiments of this application may include one or more battery cell assemblies for providing voltage and capacity. A battery cell assembly may include multiple battery cells, which are connected in series, parallel, or mixed connections via a busbar.

[0155] The battery cells in this application embodiment can be charged at high voltage and provide high capacity. Therefore, applying the battery cells to a battery device can help improve the capacity of the battery device.

[0156] In some implementations, a battery cell assembly is typically formed by arranging multiple battery cells.

[0157] As an example, a battery cell assembly can be a battery module, which is formed by arranging and fixing multiple battery cells together to form an independent module. As another example, a battery module can be formed by bundling multiple battery cells together with cable ties.

[0158] In some implementations, the battery device may be a battery pack, which includes a housing and one or more individual battery cells housed within the housing.

[0159] As an example, the battery cell assembly can be a battery module, which can be housed in a housing by fixing the battery module in the housing.

[0160] As an example, battery cell assemblies can also be housed in a housing by directly fixing multiple battery cells to the housing.

[0161] As an example, the enclosure may include a first enclosure and a second enclosure. The first enclosure and the second enclosure are fastened together to form a closed space inside the enclosure to house the individual battery cells. Here, "closed" refers to covering or closing, and can be either sealed or unsealed. The first enclosure may be a top cover or a bottom plate.

[0162] As an example, the enclosure may include a top cover, a frame, and a bottom plate. The top cover and bottom plate are connected to the frame, creating an enclosed space inside the enclosure to house the individual battery cells.

[0163] In some embodiments, the housing may be part of the vehicle's chassis structure. For example, a portion of the housing may be at least a part of the vehicle's floor, or a portion of the housing may be at least a part of the vehicle's crossbeams and longitudinal beams.

[0164] The technical solutions described in the embodiments of this application are applicable to various electrical devices that use individual battery cells, such as mobile phones, portable devices, laptops, electric vehicles, electric toys, power tools, vehicles, ships, and spacecraft. For example, spacecraft include airplanes, rockets, space shuttles, and spacecraft.

[0165] [Energy Storage Device]

[0166] This application provides an energy storage device, including multiple battery cells or multiple battery devices, wherein the battery cells or battery devices are used to store or provide electrical energy.

[0167] The aforementioned battery cells and battery devices are used to store or provide electrical energy for energy storage devices, which can increase the capacity of energy storage devices.

[0168] In some implementations, the energy storage device includes one or more battery clusters to increase the voltage and capacity of the energy storage device. A battery cluster may include multiple battery units connected in series via a busbar to increase the voltage of the energy storage device. When the energy storage device includes multiple battery clusters, the battery clusters are connected in parallel to increase the capacity of the energy storage device.

[0169] Energy storage devices can be used in energy storage power stations, wind power generation systems, solar power generation systems, mobile power systems, or temporary power supply systems. Energy storage devices can store electrical energy as needed and output it when appropriate. For example, an energy storage device can store electrical energy during off-peak hours and provide power to relevant users or electrical equipment during peak hours. The energy storage system provided in this application embodiment can be any power system that requires energy storage devices.

[0170] In some implementations, the energy storage device is an energy storage container or an energy storage cabinet.

[0171] In some implementations, the energy storage device may include a cabinet and one or more battery clusters housed within the cabinet.

[0172] In some implementations, the energy storage device may include modules such as a thermal management module, a main control module, a central control module, a power distribution module, and a fire protection module.

[0173] As an example, the thermal management module may include a liquid cooling unit that supplies coolant to each battery device via piping to regulate the temperature of the individual battery cells.

[0174] As an example, the main control module can serve as the battery management unit for the battery cluster, used to monitor and manage the battery cluster. The main control module can monitor information such as the current, voltage, power, or temperature of the battery cluster. For instance, it can control the charging and discharging current and voltage of the battery cluster. The main control module includes a slave battery management unit (SBMU), a fusion switch, and other modules.

[0175] As an example, the central control module can serve as the battery management unit for an energy storage device, used to monitor and manage the device. The central control module can monitor information such as the energy storage device's current, voltage, power, state of charge, or temperature. For instance, it can control the charging and discharging current and voltage of the energy storage device. As an example, the central control module includes modules such as an Insulation Monitoring Module (IMM), a Master Battery Management Unit (MBMU), an Ethernet (ETH) module, and a fiber optic conversion module.

[0176] As an example, the fire protection module includes a control panel, detectors, alarm devices, etc., used to detect, alarm, or extinguish fires in the energy storage system.

[0177] As an example, a power distribution module can be used to distribute power to modules in an energy storage device that require electricity.

[0178] The embodiments of this application are described in detail below. The embodiments described below are exemplary and are only used to explain this application, and should not be construed as limiting this application. Where specific techniques or conditions are not specified in the embodiments, they are performed in accordance with the techniques or conditions described in the literature in this field or according to the product instructions. Reagents or instruments used, unless otherwise specified, are all conventional products that can be obtained commercially.

[0179] Example 1

[0180] 1. Positive electrode

[0181] LiNi0.5 Co 0.1 Mn 0.4 O2 and Li2TiS3 are mixed in a molar ratio of 1:1 and ground in a mortar for 15 minutes to ensure uniform mixing. Then, the mixture is placed in a high-energy ball mill (the ball mill jar is made of zirconium oxide) and ball-milled at 2500 rpm for 10 hours to obtain the positive electrode composite material.

[0182] The positive electrode composite material, conductive agent VGCF, and sulfide electrolyte LPSCl were ground in a mortar for 20 minutes at a mass ratio of 8:0.5:1.5. Then, binder PTFE was added to form a preliminary film. The sample with the preliminary film was then placed in a roller press to form a film with a thickness of 50μm to 60μm to obtain the positive electrode film. The obtained positive electrode film was then stamped to form a positive electrode disc with a diameter of 10mm.

[0183] 2. Negative electrode

[0184] A lithium-indium alloy was used as the negative electrode. Indium powder and solid electrolyte were mixed at a mass ratio of approximately 6:4, and then compacted with lithium copper sheets to obtain the lithium-indium alloy negative electrode, wherein the molar ratio of lithium to indium was approximately 1:2.

[0185] 3. Solid electrolyte

[0186] The solid electrolyte is LPSCl.

[0187] 4. Battery Assembly

[0188] Using a solid-state battery mold, take about 100mg of LPSCl electrolyte and flatten it. Then take 100mg of lithium indium alloy negative electrode and flatten it at one end of the electrolyte. Finally, take the prepared positive electrode disc and install it at the other end of the electrolyte. Apply 4t pressure and hold for 3 minutes.

[0189] Example 2

[0190] The difference between this embodiment and Embodiment 1 is that, in the raw materials for preparing the cathode composite material, LiNi 0.5 Co 0.1 Mn 0.4 The molar ratio of O2 to Li2TiS3 is 2:1.

[0191] Example 3

[0192] The difference between this embodiment and Embodiment 1 is that, in the raw materials for preparing the cathode composite material, LiNi 0.5 Co 0.1 Mn 0.4 The molar ratio of O2 to Li2TiS3 is 1:2.

[0193] Example 4

[0194] The difference between this embodiment and Embodiment 1 is that the LiNi in the raw materials for preparing the cathode composite material is changed. 0.5 Co 0.1 Mn 0.4 O2 was replaced with an equimolar amount of LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2.

[0195] Comparative Example 1

[0196] The difference between this comparative example and Example 1 is that, in the cathode preparation process, the cathode composite material is replaced with an equal mass of Li2TiS3.

[0197] Comparative Example 2

[0198] The difference between this comparative example and Example 1 is that the LiNi in the raw materials for preparing the cathode composite material is changed. 0.5 Co 0.1 Mn 0.4 O2 was replaced with an equimolar amount of lithium iron phosphate.

[0199] Comparative Example 3

[0200] The difference between this comparative example and Example 1 is that the LiNi in the raw materials for preparing the cathode composite material is changed. 0.5 Co 0.1 Mn 0.4 O2 was replaced with an equimolar amount of lithium iron manganese.

[0201] [Structural and performance testing]

[0202] 1. Structure

[0203] 1) The X-ray diffraction pattern of the cathode composite material in Example 1 is shown in Figure 1. For comparison, LiNi is also shown in the figure. 0.5 Co 0.1 Mn 0.4 The spectrum of O2. As can be seen from the figure, the cathode composite material, compared to LiNi... 0.5 Co 0.1 Mn 0.4 O2 exhibited new diffraction peaks at 2θ values ​​of 21°–22°, 24°–25°, and approximately 32° and 34°. Meanwhile, referring to the publicly available spectra of Li2TiS3 in relevant literature, Li2TiS3 showed no diffraction peaks in the 2θ range of 20°–30°, but diffraction peaks appeared near 2θ values ​​of 32° and 34°. Therefore, the diffraction peaks in the 2θ range of 20°–30° in the cathode composite material, i.e., the diffraction peaks at 21°–22° and 24°–25°, are not LiNi. 0.5 Co 0.1 Mn 0.4The diffraction peaks of O2 and Li2TiS3 are not the same, indicating that LiNi 0.5 Co 0.1 Mn 0.4 The cathode composite material obtained after co-ball milling of O2 and Li2TiS3 exhibited a new phase, containing a new compound instead of LiNi. 0.5 Co 0.1 Mn 0.4 Physical mixing of O2 and Li2TiS3.

[0204] The aforementioned characteristic diffraction peaks were also observed in the X-ray diffraction patterns of the cathode composite materials in Examples 2 to 4. Furthermore, based on the X-ray diffraction patterns of the cathode composite materials in each example, the following crystal structure was obtained: the relationship between the c-axis cell parameter c and the a-axis cell parameter a satisfies: c > 4.9a; the numerical range of the a-axis cell parameter a is 2.8–3.0; the numerical range of the c-axis cell parameter c is 14.2–14.3; and the diffraction peak intensity I of the 003 crystal plane (2θ is 21°–22°) is... 003 The diffraction peak intensity I of the 101 crystal plane (2θ is 24°~25°) 101 The ratio satisfies: 0.18 101 / I 003 <0.2.

[0205] In addition, considering LiNi 0.5 Co 0.1 Mn 0.4 O2 is commonly used as the positive electrode active material in lithium-ion batteries due to its high specific capacity and high voltage plateau. Therefore, this application investigated the composite of other positive electrode active materials with high specific capacity and high voltage plateau with Li2TiS3, namely Comparative Examples 2 and 3. Comparative Examples 2 and 3 prepared positive electrode composite materials by combining lithium iron phosphate and lithium manganese oxide with Li2TiS3 using the same methods as in Examples 1 to 3. The X-ray diffraction patterns of the positive electrode composite materials prepared in Comparative Examples 2 and 3 only showed diffraction peaks for lithium iron phosphate and Li2TiS3, or lithium manganese iron and Li2TiS3, without observing any new diffraction peaks. This suggests that ball milling of lithium iron phosphate and Li2TiS3, or lithium manganese iron and Li2TiS3, resulted in a physical mixture of raw materials without the formation of new compounds.

[0206] 2) ICP-OES tests were performed on the Li2TiS3 and the cathode composite material of Example 4, and the mass percentage of each element is shown in the table below (since S and O are in the far ultraviolet region, these two elements were not detected).

[0207] [Table 1] ​

[0208] Based on the ICP-OES test results, the cathode composite material of Example 4 basically achieves Li2TiS3 and LiNi. 1 / 3 Co 1 / 3 Mn 1 / 3 The O2 molar ratio is 1:1. Based on Li2TiS3 and LiNi... 1 / 3 Co 1 / 3 Mn 1 / 3 The molar ratio of O2 determines the chemical formula of the positive electrode composite material in Example 4 as Li. 1.5 Ti 0.5 Ni 0.17 Mn 0.17 Co 0.17 OS 1.5 .

[0209] Following the same method, the chemical formulas of the cathode composite materials in each embodiment were obtained as shown in Table 2.

[0210] [Table 2]

[0211] 2. Electrochemical performance

[0212] Using a battery testing system, a constant current charge-discharge method was employed, with a nominal specific capacity of 200 mAh / g. At 25°C, the assembled mold battery was first activated three times at a 0.1C rate. Then, under full charge, it was discharged at a constant current rate of 0.33C until the discharge cutoff voltage. The specific capacity of the first discharge cycle and the median discharge voltage (i.e., the plateau voltage) were recorded.

[0213] Then, using the same method, three cycles were performed at 0.1C, 0.2C, 0.5C, 1C, and 2C rates, and the corresponding discharge capacities were recorded.

[0214] 1) First-cycle specific capacity and median discharge voltage

[0215] The initial discharge specific capacity and median discharge voltage of each embodiment and comparative example are shown in Table 3 below, and the capacity curves of Embodiment 1 and Comparative Example 1 are shown in Figure 2.

[0216] [Table 3]

[0217] Test results show that the initial discharge specific capacity of Li₂TiS₃ in Comparative Example 1 is low, only about 148 mAh / g, and the charge / discharge voltage is low, with a median discharge voltage of only 2.4V. In contrast, Examples 1-3 use Li₂TiS₃ and LiNi 0.5 Co 0.1 Mn 0.4When O2 is used together to form a positive electrode composite material, the first discharge specific capacity can be significantly improved, reaching 178mAh / g to 198mAh / g, and the charge and discharge window is significantly widened, with the median discharge voltage reaching 3.4V to 3.8V.

[0218] Meanwhile, although Comparative Examples 2 and 3 ball-milled LiFePO4 or LiMnO4 with Li2TiS3, which have high specific capacity and high voltage platform, Comparative Example 2 experienced a short circuit during the test (the capacity was abnormally low during the test, and the system reported an error after reaching a certain voltage). The first discharge specific capacity and discharge median voltage of Comparative Examples 2 and 3 not only did not improve, but were actually lower than those of Li2TiS3 in Comparative Example 1.

[0219] 2) Ratio performance

[0220] The rate performance curves for Example 1 and Comparative Example 1 are shown in Figure 3. As can be seen from the figure, the cathode composite material of Example 1 exhibits better rate performance than the Li2TiS3 of Comparative Example 1, maintaining a relatively stable and high capacity during charge-discharge cycles at different rates. Meanwhile, the rate performance of Comparative Example 3 was found to be lower than that of Comparative Example 1 during testing.

[0221] It should be noted that this application is not limited to the above-described embodiments. The above embodiments are merely examples, and any embodiments with the same structure and effect as the technical concept within the scope of this application are included in the technical scope of this application. Furthermore, various modifications that can be conceived by those skilled in the art to the embodiments, and other ways of constructing by combining some of the constituent elements of the embodiments, without departing from the spirit of this application, are also included in the scope of this application.

Claims

1. A battery cell, characterized in that, includes a positive electrode sheet, the positive electrode sheet includes a positive electrode active layer, the positive electrode active layer includes a positive electrode composite, a chemical formula of the positive electrode composite includes Li a M 1 b M 2 c M 3 d M 4 e O f S g ; wherein M 1 comprising one or more of Ti, Nb, M 2 , M 3 , M 4 each independently comprises one or more of a transition metal, Al, and M 1 , M 2 , M 3 , M 4 are different metal elements; a=1~2, b=0.1~1, 0<c≤0.5, 0<d≤0.5, 0<e≤0.5, f=0.1~2, g=0.1~3.

2. The battery cell according to claim 1, characterized in that, a = 1.2 to 1.7; and / or, b = 0.3–0.7; and / or, c = 0.01–0.5; and / or, d = 0.01–0.5; and / or, e = 0.01–0.5; and / or, f = 0.5–1.5; and / or, g＝1～2。 3. The battery cell according to claim 1 or 2, characterized in that, The transition metal includes one or more of Ni, Co, and Mn.

4. The battery cell according to any one of claims 1 to 3, characterized in that, M 2 including Ni, c = 0.05 to 0.

5.

5. The battery cell according to any one of claims 1 to 4, characterized in that, M 3 including one or more of Mn, Al, d = 0.08-0.

4.

6. The battery cell according to any one of claims 1 to 5, characterized in that, M 4 Co, e = 0.01-0.

2.

7. The battery cell according to any one of claims 1 to 6, characterized in that, The positive electrode composite includes Li 1.5 Ti 0.5 Ni 0.25 Mn 0.2 Co 0.05 OS 1.5 , Li 1.33 Ti 0.33 Ni 0.33 Mn 0.27 Co 0.07 O 1.33 S, Li 1.67 Ti 0.67 Ni 0.17 Mn 0.13 Co 0.03 O 0.67 S2, Li 1.5 Ti 0.5 Ni 0.17 Mn 0.17 Co 0.17 OS 1.5 one or more of 8. The battery cell according to any one of claims 1 to 7, characterized in that, The positive electrode composite material has a periodic layered structure; and / or, the space group of the positive electrode composite material is R-3m.

9. The battery cell according to any one of claims 1 to 8, characterized in that, In the X-ray diffraction pattern of the positive electrode composite material, diffraction peaks appear at positions where 2θ is 21°~22° and 24°~25°.

10. The battery cell according to any one of claims 1 to 9, characterized in that, In the X-ray diffraction pattern of the cathode composite material, the relationship between the c-axis unit cell parameter c and the a-axis unit cell parameter a satisfies: c > 4.9a; and / or, The unit cell parameter 'a' of the a-axis ranges from 2.8 to 3.0; the unit cell parameter 'c' of the c-axis ranges from 14.2 to 14.3; and / or, Diffraction peak intensity I of the 003 crystal plane 003 The diffraction peak intensity I of the 101 crystal plane 101 The ratio satisfies: 0.18 101 / I 003 <0.2.​ 11. The battery cell according to any one of claims 1 to 10, characterized in that, The positive electrode active layer also includes a solid electrolyte, which includes a sulfide solid electrolyte.

12. A positive electrode plate, characterized in that, The positive electrode tab includes a positive electrode active layer, the positive electrode active layer includes a positive electrode composite, the chemical formula of the positive electrode composite includes Li a M 1 b M 2 c M 3 d M 4 e O f S g ; wherein M 1 comprising one or more of Ti, Nb, M 2 , M 3 , M 4 each independently comprises one or more of a transition metal, Al, and M 1 , M 2 , M 3 , M 4 are different metal elements; a=1~2, b=0.1~1, 0<c≤0.5, 0<d≤0.5, 0<e≤0.5, f=0.1~2, g=0.1~3.

13. The positive electrode sheet according to claim 12, characterized in that, The positive electrode active layer also includes a solid electrolyte, which includes a sulfide solid electrolyte.

14. A positive electrode composite material, characterized in that, Chemical formula includes Li a M 1 b M 2 c M 3 d M 4 e O f S g ; wherein M 1 comprising one or more of Ti, Nb, M 2 , M 3 , M 4 each independently comprises one or more of a transition metal, Al, and M 1 , M 2 , M 3 , M 4 are each a different metal element; a=1~2, b=0.1~1, 0<c≤0.5, 0<d≤0.5, 0<e≤0.5, f=0.1~2, g=0.1~3.

15. A method for preparing a positive electrode composite material, characterized in that, comprising the steps of: reacting a multinary lithium metal oxide or a modified compound thereof, a sulfur-based lithium compound or a modified compound thereof, in a protective atmosphere, according to Li a M 1 b M 2 c M 3 d M 4 e O f S g in the elemental ratio of Li : Mn : Co : Ni : O : S = 1 : 1 : 1 : 1 : 3 :

1. wherein the sulfur-based lithium compound comprises M 1 , the polybasic lithium metal oxide comprises M 2 , M 3 , M 4 , M 1 one or more of Ti, Nb, M 2 , M 3 , M 4 each independently comprises one or more of a transition metal, Al, and M 1 , M 2 , M 3 , M 4 are different metal elements; a=1~2, b=0.1~1, 0<c≤0.5, 0<d≤0.5, 0<e≤0.5, f=0.1~2, g=0.1~3.

16. The method for preparing the positive electrode composite material according to claim 15, characterized in that, The multi-component lithium metal oxide includes ternary materials.

17. The method for preparing the positive electrode composite material according to claim 16, characterized in that, The ternary material includes one or more of nickel-cobalt-manganese ternary materials and nickel-cobalt-aluminum ternary materials.

18. The method for preparing the positive electrode composite material according to any one of claims 15 to 17, characterized in that, The sulfur-based lithium compounds include Li₂TiS₃, Li₂NbS₃, Li₃NbS₄, and Li₂Ti 1-x3 Si x3 One or more of S3, where 0 < x3 ≤ 0.

5.

19. The method for preparing the positive electrode composite material according to any one of claims 15 to 18, characterized in that, The molar ratio between the multi-component lithium metal oxide or its modified compound and the sulfur-based lithium compound or its modified compound is 1:(0.5-2).

20. The method for preparing the positive electrode composite material according to claim 19, characterized in that, The molar ratio between the multi-component lithium metal oxide or its modified compound and the sulfur-based lithium compound or its modified compound is 1:(0.8 to 1.5).

21. The method for preparing the positive electrode composite material according to any one of claims 15 to 20, characterized in that, The method for reacting the multi-component lithium metal oxide or its modified compound, the sulfur-based lithium compound or its modified compound, includes one or more of ball milling and sintering processes.

22. The method for preparing the positive electrode composite material according to claim 21, characterized in that, The ball milling process is performed at a speed of 2000 rpm to 5000 rpm for a duration of 10 h to 30 h.

23. A battery device, characterized in that, It includes the battery cell described in any one of claims 1 to 11.

24. An energy storage device, characterized in that, It includes a battery cell according to any one of claims 1 to 11 or a battery device according to claims 23, wherein the battery cell or the battery device is used to store or provide electrical energy.

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