Battery monomer, battery device and power utilization device

Abstract

The invention relates to a battery monomer, a battery device and a power utilization device. The battery monomer comprises a positive pole piece, a separator and a negative pole piece, at least one of the positive pole piece, the separator and the negative pole piece contains an additive; the additive is an organic small molecule, an organic polymer or an organic salt with a functional group A; the functional group A comprises at least two chelating groups, and each chelating group is independently selected from a phosphate group or a phosphate group. According to the battery monomer, the additive is applied, so that the effect of chelating transition metal ions is achieved, the negative effect caused by dissolution of transition metal is reduced, and the capacity retention ratio of the battery under circulation and storage conditions is favorably improved.

Description

Technical Field

[0001] This application relates to the field of battery technology, specifically to a battery cell, a battery device, and an electrical device. Background Technology

[0002] Secondary batteries, represented by lithium-ion batteries, are widely used in energy storage power systems such as hydropower, thermal power, wind power, and solar power plants, as well as in power tools, electric bicycles, electric motorcycles, electric cars, military equipment, aerospace, and many other fields. The application of secondary batteries has placed higher demands on their performance.

[0003] When a secondary battery uses a positive electrode active material containing transition metal oxides, the transition metals can easily shuttle to the negative electrode during charging and discharging, and be reduced on the surface of the negative electrode. This can lead to adverse reactions such as SEI film breakage and reconstruction, and further degrade battery performance. Summary of the Invention

[0004] The purpose of this application is to provide a battery cell, a battery device, and an electrical device. The battery cell, through the application of additives, plays a role in chelating transition metal ions, reducing the negative effects of transition metal dissolution, and is conducive to improving the capacity retention rate of the battery under cycling and storage conditions.

[0005] Therefore, the first aspect of this application provides a battery cell, including a positive electrode, a separator, and a negative electrode;

[0006] At least one of the positive electrode, the separator, and the negative electrode contains an additive;

[0007] The additive is an organic small molecule, organic polymer, or organic salt having a functional group A;

[0008] The functional group A includes at least two chelating groups, each of which is independently selected from a phosphate group or a phosphate group.

[0009] The aforementioned additives contain functional groups including at least two phosphate groups or phosphate groups, wherein the P=O group can chelate with transition metal ions. Compared with other elements used for chelating transition metals (such as nitrogen), these additives have advantages in thermal stability and oxidation resistance. Therefore, by applying the aforementioned additives to at least one of the positive electrode, separator, and negative electrode of a battery cell, transition metal ions can be significantly and effectively chelated. This helps to eliminate or reduce adverse reactions caused by transition metal ion shuttle, thereby optimizing the battery's capacity retention under cycling and storage conditions.

[0010] In some embodiments, the additive contains at least two functional groups A.

[0011] When the additive contains at least two of the above-mentioned functional groups A, it can form a more toothed chelate structure for transition metal ions, which is beneficial to improve the stability of chelation and thus better eliminate the adverse effects of transition metal ions.

[0012] In some embodiments, in the functional group A, each chelating group is directly or via an alkylene group coupled to the same atom X, where X is selected from O, N, and S.

[0013] When functional group A possesses the aforementioned characteristics, element X can also participate in chelation, enhancing the stability of the chelation. In particular, X, in conjunction with chelating groups, can form a hexadecantal chelate structure with transition metal ions, which exhibits superior stability compared to the tetradentate chelate structure formed when nitrogen is used alone to chelate transition metal elements.

[0014] In some embodiments, the phosphate group includes at least one of the following: lithium phosphate group, sodium phosphate group, potassium phosphate group, ammonium phosphate group, and zinc phosphate group.

[0015] The phosphate group has a P=O metal cation (e.g., P=O-Li). + The structure (etc.) is beneficial to enhance ion transport capability, thereby reducing charge transfer impedance and enabling the battery cell to have better rate performance.

[0016] In some embodiments, the functional group A is -X-((CH2)). n -PO3M1 a H b ) c Where X is selected from O, N, and S, n is an integer from 0 to 2, and M1 is selected from Li cations with valence state m. + Na + K + NH4 + Zn 2+ One of them, (a*m)+b=2, c=2 or 3.

[0017] When the functional group has the above chemical formula, its overall structure is more reasonable (including alkylene length, X element type, cation type, etc.), which is conducive to improving the stability of its chelation of transition metal ions and further improving the capacity retention rate of the battery under cycling and storage conditions.

[0018] In some embodiments, the additive includes at least one of the following: hydroxyethylidene diphosphate (HEDP) or a salt thereof, aminotrimethylene phosphate (AMTP) or a salt thereof, ethylenediaminetetramethylenephosphonic acid (EDTMP) or a salt thereof, hexamethylenediaminetetramethylenephosphonic acid (HDTMPA) or a salt thereof, bis(1,6-hexyltriaminepentimethylenephosphonic acid) (BHMTPMPA) or a salt thereof, and lithium p-phenol-2-ethyl diphosphate.

[0019] The additives mentioned above are readily available and better suited to the secondary battery system. Without negatively impacting battery function, they are beneficial for further improving the chelation effect on transition metals.

[0020] In some embodiments, the positive electrode sheet includes a positive current collector and a positive electrode material layer disposed on at least one surface of the positive current collector, the positive electrode material layer including a positive electrode active material;

[0021] The positive electrode active material includes at least one of the compounds shown in formula (I) and formula (II);

[0022] Li 1+d [Ni x Co y Mn z M2 e O2 formula (I)

[0023] Wherein, 0.6≤x<1, 0<y<0.3, 0<z<0.3, -0.1<d<0.2, 0<e<0.2, x+y+z+e=1, and M2 includes one or more of Mg, Ca, Sb, Ce, Ti, Zr, Sr, Al, Zn, Mo, Y, W, Ta, F and B;

[0024] (LiMn p Fe 1-p-q M3 q PO4) Formula (II)

[0025] Wherein, 0.1≤p≤0.9, 0≤q≤0.05, and M3 includes one or more of V, Ti, Mg, Ni, Fe, Sn, and F.

[0026] When using the aforementioned cathode active materials with high transition metal content, the adverse effects of transition metal dissolution can be effectively reduced through the chelating effect of additives. Therefore, when using the aforementioned cathode active materials, the battery cell can simultaneously possess high energy density, cycle performance, and storage performance.

[0027] In some embodiments, the positive electrode sheet includes a positive current collector and a positive electrode material layer disposed on at least one surface of the positive current collector, the positive electrode material layer comprising a positive electrode active material and the additive; wherein the additive in the positive electrode material layer accounts for 0.2% to 1.0% by mass.

[0028] When the positive electrode contains the additives, keeping the additive content within the above range allows for a more thorough chelation effect on dissolved transition metals, while avoiding negative impacts on the battery's DC internal resistance (DCR), thus improving the battery's cycle and storage performance.

[0029] In some embodiments, the negative electrode sheet includes a negative electrode current collector and a negative electrode material layer disposed on at least one surface of the negative electrode current collector, the negative electrode material layer including a negative electrode active material and the additive; in the negative electrode material layer, the mass percentage of the additive is 0.2% to 1.0%.

[0030] By placing additives on the surface of the negative electrode, the transition metals reaching the negative electrode can be chelated, minimizing their reduction on the negative electrode surface. When additives are used on the negative electrode, the above-mentioned mass ratio is more conducive to chelating the transition metals before they are reduced, thus avoiding adverse effects on the SEI film.

[0031] In some embodiments, the separator includes a base film and a film layer disposed on at least one surface of the base film, the film layer containing the additive; wherein the additive in the film layer accounts for 0.05% to 0.2% by mass.

[0032] When additives are placed on the separator, they can chelate transition metal ions that dissolve from the positive electrode into the electrolyte, thus acting as an interceptor. When additives are used in the separator, the above-mentioned mass percentage is more conducive to their chelation of transition metal ions in the electrolyte, thereby greatly preventing transition metal ions from shuttling to the negative electrode surface.

[0033] A second aspect of this application provides a positive electrode sheet, which includes a positive current collector and a positive electrode material layer disposed on at least one surface of the positive current collector, the positive electrode material layer comprising a positive electrode active material and additives;

[0034] The additive is an organic small molecule, organic polymer, or organic salt having a functional group A;

[0035] The functional group A includes at least two chelating groups, each of which is independently selected from a phosphate group or a phosphate group.

[0036] By applying the above-mentioned additives to the positive electrode of the battery cell, transition metal ions can be significantly and effectively chelated, which helps to eliminate or reduce adverse reactions caused by transition metal ion shuttle, thereby optimizing the capacity retention rate of the battery under cycle and storage conditions.

[0037] In some embodiments, the additive accounts for 0.2% to 1.0% of the mass of the positive electrode material layer.

[0038] In some embodiments, the additive contains at least two functional groups A.

[0039] In some embodiments, in the functional group A, each chelating group is directly or via an alkylene group coupled to the same atom X, where X is selected from O, N, and S.

[0040] In some embodiments, the phosphate group includes at least one of the following: lithium phosphate group, sodium phosphate group, potassium phosphate group, ammonium phosphate group, and zinc phosphate group.

[0041] In some embodiments, the functional group A is -X-((CH2)). n -PO3M1 a H b ) c Where X is selected from O, N, and S, n is an integer between 0 and 2, and M1 is selected from Li cations with valence state m. + Na + K + NH4 + Zn 2+ One of them, (a*m)+b=2, c=2 or 3.

[0042] In some embodiments, the additive includes at least one of the following: hydroxyethylidene diphosphate or a salt thereof, aminotrimethylene phosphate or a salt thereof, ethylenediaminetetramethylenephosphonic acid or a salt thereof, hexamethylenediaminetetramethylenephosphonic acid or a salt thereof, bis(1,6-hexyltriaminepentimethylenephosphonic acid or a salt thereof, and lithium p-phenol-2-ethyldiphosphate.

[0043] In some embodiments, the positive electrode active material includes at least one of the compounds shown in formula (I) and formula (II);

[0044] Li 1+d [Ni x Co y Mn z M2 e O2 formula (I)

[0045] Wherein, 0.6≤x<1, 0<y<0.3, 0<z<0.3, -0.1<d<0.2, 0<e<0.2, x+y+z+e=1, and M2 includes one or more of Mg, Ca, Sb, Ce, Ti, Zr, Sr, Al, Zn, Mo, Y, W, Ta, F and B;

[0046] (LiMn p Fe 1-p-q M3 q PO4) Formula (II)

[0047] Wherein, 0.1≤p≤0.9, 0≤q≤0.05, and M3 includes one or more of V, Ti, Mg, Ni, Fe, Sn, and F.

[0048] A third aspect of this application provides a method for preparing a positive electrode sheet, comprising,

[0049] Provides positive current collector;

[0050] A positive electrode material layer is disposed on at least one surface of the positive electrode current collector, the positive electrode material layer comprising a positive electrode active material and additives;

[0051] The additive is an organic small molecule, organic polymer, or organic salt having a functional group A;

[0052] The functional group A includes at least two chelating groups, each of which is independently selected from a phosphate group or a phosphate group.

[0053] This application provides a negative electrode sheet comprising a negative electrode current collector and a negative electrode material layer disposed on at least one surface of the negative electrode current collector, the negative electrode material layer comprising a negative electrode active material and additives.

[0054] The additive is an organic small molecule, organic polymer, or organic salt having a functional group A;

[0055] The functional group A includes at least two chelating groups, each of which is independently selected from a phosphate group or a phosphate group.

[0056] By applying the above-mentioned additives to the negative electrode of the battery cell, transition metal ions can be significantly and effectively chelated, which helps to eliminate or reduce adverse reactions caused by transition metal ion shuttle, thereby optimizing the capacity retention rate of the battery under cycle and storage conditions.

[0057] In some embodiments, the additive accounts for 0.2% to 1.0% of the mass of the negative electrode material layer.

[0058] In some embodiments, the additive contains at least two functional groups A.

[0059] In some embodiments, in the functional group A, each chelating group is directly or via an alkylene group coupled to the same atom X, where X is selected from O, N, and S.

[0060] In some embodiments, the phosphate group includes at least one of the following: lithium phosphate group, sodium phosphate group, potassium phosphate group, ammonium phosphate group, and zinc phosphate group.

[0061] In some embodiments, the functional group A is -X-((CH2)). n -PO3M1 a H b ) c Where X is selected from O, N, and S, n is an integer between 0 and 2, and M1 is selected from Li cations with valence state m. + Na + K + NH4 + Zn 2+ One of them, (a*m)+b=2, c=2 or 3.

[0062] In some embodiments, the additive includes at least one of the following: hydroxyethylidene diphosphate or a salt thereof, aminotrimethylene phosphate or a salt thereof, ethylenediaminetetramethylenephosphonic acid or a salt thereof, hexamethylenediaminetetramethylenephosphonic acid or a salt thereof, bis(1,6-hexyltriaminepentimethylenephosphonic acid or a salt thereof, and lithium p-phenol-2-ethyldiphosphate.

[0063] The fifth aspect of this application provides a method for preparing a negative electrode sheet, comprising,

[0064] Provide negative electrode current collector;

[0065] A negative electrode material layer is disposed on at least one surface of the negative electrode current collector, the negative electrode material layer comprising a negative electrode active material and additives;

[0066] The additive is an organic small molecule, organic polymer, or organic salt having a functional group A;

[0067] The functional group A includes at least two chelating groups, each of which is independently selected from a phosphate group or a phosphate group.

[0068] A sixth aspect of this application provides a separating membrane comprising a base membrane and a membrane layer disposed on at least one surface of the base membrane, the membrane layer comprising an additive;

[0069] The additive is an organic small molecule, organic polymer, or organic salt having a functional group A;

[0070] The functional group A includes at least two chelating groups, each of which is independently selected from a phosphate group or a phosphate group.

[0071] By applying the above-mentioned additives to the separator of the battery cell, transition metal ions can be significantly and effectively chelated, which helps to eliminate or reduce adverse reactions caused by transition metal ion shuttle, thereby optimizing the capacity retention rate of the battery under cycle and storage conditions.

[0072] In some embodiments, the additive accounts for 0.05% to 0.2% of the mass of the film layer.

[0073] In some embodiments, the additive contains at least two functional groups A.

[0074] In some embodiments, in the functional group A, each chelating group is directly or via an alkylene group coupled to the same atom X, where X is selected from O, N, and S.

[0075] In some embodiments, the phosphate group includes at least one of the following: lithium phosphate group, sodium phosphate group, potassium phosphate group, ammonium phosphate group, and zinc phosphate group.

[0076] In some embodiments, the functional group A is -X-((CH2)). n -PO3M1 a H b ) c Where X is selected from O, N, and S, n is an integer between 0 and 2, and M1 is selected from Li cations with valence state m. + Na + K + NH4 + Zn 2+ One of them, (a*m)+b=2, c=2 or 3.

[0077] In some embodiments, the additive includes at least one of the following: hydroxyethylidene diphosphate or a salt thereof, aminotrimethylene phosphate or a salt thereof, ethylenediaminetetramethylenephosphonic acid or a salt thereof, hexamethylenediaminetetramethylenephosphonic acid or a salt thereof, bis(1,6-hexyltriaminepentimethylenephosphonic acid or a salt thereof, and lithium p-phenol-2-ethyldiphosphate.

[0078] The seventh aspect of this application provides a method for preparing a separator membrane, comprising,

[0079] Provide base film;

[0080] A film layer is disposed on at least one surface of the base film, the film layer comprising an additive; the additive is an organic small molecule, organic polymer, or organic salt having a functional group A;

[0081] The functional group A includes at least two chelating groups, each of which is independently selected from a phosphate group or a phosphate group.

[0082] An eighth aspect of this application provides a battery device comprising a battery cell as described in the first aspect of this application, a positive electrode as described in the second aspect of this application, a positive electrode prepared according to the preparation method described in the third aspect of this application, a negative electrode as described in the fourth aspect of this application, a negative electrode prepared according to the preparation method described in the fifth aspect of this application, and a separator as described in the sixth aspect of this application or a separator prepared according to the preparation method described in the seventh aspect of this application.

[0083] The ninth aspect of this application provides an electrical device comprising a battery cell as described in the first aspect of this application, a positive electrode as described in the second aspect of this application, a positive electrode prepared according to the preparation method described in the third aspect of this application, a negative electrode as described in the fourth aspect of this application, a negative electrode prepared according to the preparation method described in the fifth aspect of this application, a separator as described in the sixth aspect of this application, or a separator prepared according to the preparation method described in the seventh aspect of this application, or a battery device as described in the eighth aspect of this application.

[0084] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application, it can be implemented according to the contents of the specification. In order to make the above and other objects, features and advantages of this application more obvious and understandable, the specific implementation methods of this application are listed below. Attached Figure Description

[0085] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the scope of this application. In the drawings:

[0086] Figure 1 This is a schematic diagram of a battery cell according to one embodiment of this application;

[0087] Figure 2 yes Figure 1 An exploded view of a battery cell according to one embodiment of this application is shown.

[0088] Figure 3 This is a schematic diagram of a battery module according to one embodiment of this application;

[0089] Figure 4 This is a schematic diagram of a battery pack according to one embodiment of this application;

[0090] Figure 5 yes Figure 4An exploded view of a battery pack according to one embodiment of this application is shown;

[0091] Figure 6 This is a schematic diagram of an electrical device in which a single battery cell is used as a power source according to one embodiment of this application;

[0092] Figure 7 This is a schematic diagram of the hexadecimal chelate structure formed by the additive and transition metal ions in one embodiment of this application;

[0093] Figure 8 This is a scanning electron microscope imaging result of a negative electrode sheet containing additives in one embodiment of this application; wherein, the left image is a top view of the negative electrode sheet, in which graphite is uniformly distributed in the negative electrode, and the right image is a surface scan of the elemental distribution in the left image, in which it is clearly seen that the additive containing the characteristic element phosphorus P is uniformly distributed on the surface of the graphite, indicating that the additive is uniformly distributed.

[0094] Explanation of reference numerals in the attached figures:

[0095] 1 Battery pack; 2 Upper housing; 3 Lower housing; 4 Battery module; 5 Battery cell; 51 Casing; 52 Electrode assembly; 53 End cap. Detailed Implementation

[0096] Exemplary embodiments of this disclosure will now be described in more detail. It should be understood that this disclosure may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of this disclosure to those skilled in the art.

[0097] 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 the 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 expected that ranges of 60–110 and 80–120 are also included. Furthermore, if minimum range values ​​1 and 2 are listed, and maximum range values ​​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.

[0098] Unless otherwise specified, all embodiments and optional embodiments of this application can be combined to form new technical solutions.

[0099] Unless otherwise specified, all technical features and optional technical features of this application may be combined to form new technical solutions.

[0100] Unless otherwise specified, all steps of 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.

[0101] 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.

[0102] Secondary batteries, represented by lithium-ion batteries, have been widely used. When secondary batteries use positive electrode active materials containing transition metal oxides, the transition metals can easily shuttle to the negative electrode during charging and discharging, and be reduced on the surface of the negative electrode. This may cause adverse reactions such as SEI film breakage and reconstruction, and further degrade battery performance.

[0103] This application mainly improves battery performance by using an additive containing phosphate or phosphate groups in the battery cell, which can chelate transition metals, thereby reducing the adverse effects of free transition metals.

[0104] The solutions described in the embodiments of this application are applicable to battery cells, battery devices using battery cells, and electrical devices using at least one of the battery cells and battery devices.

[0105] battery cell

[0106] In this embodiment of the application, the battery cell can be a secondary battery, which refers to a battery cell that can be recharged to activate the active materials and continue to be used after the battery cell has been discharged.

[0107] The battery cell can be a lithium-ion battery, sodium-ion battery, sodium-lithium-ion battery, lithium metal battery, sodium metal battery, lithium-sulfur battery, magnesium-ion battery, nickel-metal hydride battery, nickel-cadmium battery, lead-acid battery, etc. In some embodiments, the battery cell is a lithium-ion battery.

[0108] [Electrode Assembly]

[0109] A single battery cell typically includes an electrode assembly. The electrode assembly includes a positive electrode, a negative electrode, and a separator, with the separator positioned between the positive and negative electrodes. During the charging and discharging process of a single battery cell, active ions (such as lithium ions) repeatedly insert and extract between the positive and negative electrodes. The separator, positioned between the positive and negative electrodes, prevents short circuits between the positive and negative electrodes while allowing active ions to pass through.

[0110] In some embodiments of this application, a battery cell is provided, including a positive electrode, a separator, and a negative electrode;

[0111] At least one of the positive electrode, the separator, and the negative electrode contains an additive;

[0112] The additive is an organic small molecule, organic polymer, or organic salt having a functional group A;

[0113] The functional group A includes at least two chelating groups, each of which is independently selected from a phosphate group or a phosphate group.

[0114] The aforementioned additives contain functional groups including at least two phosphate groups or phosphate groups, wherein the P=O group can chelate with transition metal ions. Compared with other elements used for chelating transition metals (such as nitrogen), these additives have advantages in thermal stability and oxidation resistance. Therefore, by applying the aforementioned additives to at least one of the positive electrode, separator, and negative electrode of a battery cell, transition metal ions can be significantly and effectively chelated. This helps to eliminate or reduce adverse reactions caused by transition metal ion shuttle, thereby optimizing the battery's capacity retention under cycling and storage conditions.

[0115] In some embodiments, the additive contains at least two functional groups A; for example, the number of functional groups A can be two, three, four, five, etc.

[0116] When the additive contains at least two of the above-mentioned functional groups A, it can form a more toothed chelate structure for transition metal ions, which is beneficial to improve the stability of chelation and thus better eliminate the adverse effects of transition metal ions.

[0117] In some embodiments, in the functional group A, each chelating group is directly or via an alkylene group coupled to the same atom X, where X is selected from O, N, and S.

[0118] When functional group A possesses the aforementioned characteristics, element X can also participate in chelation, enhancing the stability of the chelation. In particular, when X combines with two chelating groups, it can form a hexadecantal chelate structure with transition metal ions, which exhibits superior stability compared to the tetradentate chelate structure formed when nitrogen is used alone to chelate transition metal elements.

[0119] In some embodiments, the phosphate group includes at least one of the following: lithium phosphate group (-PO3LiH, -PO3Li2), sodium phosphate group (-PO3NaH, -PO3Na2), potassium phosphate group (-PO3KH, -PO3K2), ammonium phosphate group (-PO3(NH4)H, -PO3(NH4)2), and zinc phosphate group (-PO3Zn).

[0120] The phosphate group has a P=O- metal cation (e.g., P=O-Li). + The structure (etc.) is beneficial to enhance ion transport capability, thereby reducing charge transfer impedance and enabling the battery cell to have better rate performance.

[0121] In some embodiments, the functional group A is -X-((CH2)). n -PO3M1 a H b ) cWhere X is selected from O, N, and S, n is an integer from 0 to 2, and M1 is selected from Li cations with valence state m. + Na + K + NH4 + Zn 2+ One of them, (a*m)+b=2, c=2 or 3.

[0122] When the functional group has the above chemical formula, its overall structure is more reasonable (including alkylene length, X element type, cation type, etc.), which is conducive to improving the stability of its chelation of transition metal ions and further improving the capacity retention rate of the battery under cycling and storage conditions.

[0123] The additives described in the embodiments of this application can be in liquid form such as solutions and dispersions, or in solid form such as powders. In some embodiments, the additives include at least one of the following: hydroxyethylidene diphosphate (HEDP) or a salt thereof, aminotrimethylene phosphate (AMTP) or a salt thereof, ethylenediaminetetramethylenephosphonic acid (EDTMP) or a salt thereof, hexamethylenediaminetetramethylenephosphonic acid (HDTMPA) or a salt thereof, bis(1,6-hexanetriaminepentanephosphonic acid) (BHMTPMPA) or a salt thereof, and lithium p-phenol-2-ethyl diphosphate. Specifically, the salts may be lithium salts, sodium salts, potassium salts, ammonium salts, etc. For example, the additive may be selected from: lithium hydroxyethylidene diphosphate (HEDP-4Li), lithium aminotrimethylene phosphate (AMTP-6Li), zinc aminotrimethylene phosphate (ATMP-3Zn), sodium aminotrimethylene phosphate (ATMP-6Na), ammonium aminotrimethylene phosphate (ATMP-6NH4), lithium ethylenediaminetetramethylene phosphate (EDTMP-8Li), lithium bis(1,6-hexyltriaminepentamethylenephosphonate) (BHMTMP-10Li), and lithium hexamethylenediaminetetramethylenephosphonate (HDTMPA-8Li).

[0124] The additives mentioned above are readily available and better suited to the secondary battery system. Without negatively impacting battery function, they are beneficial for further improving the chelation effect on transition metals.

[0125] [Positive electrode plate]

[0126] In some embodiments, the positive electrode includes a positive current collector and a positive electrode material layer disposed on at least one surface of the positive current collector, the positive electrode material layer containing a positive active material; when at least one of the separator and the negative electrode in the battery cell contains the additive, the positive electrode material layer may not contain the additive.

[0127] In some embodiments, the positive electrode includes a positive current collector and a positive electrode material layer disposed on at least one surface of the positive current collector, the positive electrode material layer comprising a positive electrode active material and the additive. The additive can be applied to the positive electrode material layer to chelate dissolved transition metal ions.

[0128] In some embodiments, the additive in the positive electrode material layer accounts for 0.2% to 1.0% by mass; for example, it can be about 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1.0%, etc.

[0129] When the positive electrode contains the additives, keeping the additive content within the above range allows for a more thorough chelation effect on dissolved transition metals, while avoiding negative impacts on the battery's DC internal resistance (DCR), thus improving the battery's cycle and storage performance.

[0130] In some embodiments, the positive current collector may be a metal foil or a composite current collector. For example, aluminum foil may be used as the metal foil. The composite current collector may include a polymer substrate and a metal layer formed on at least one surface of the polymer substrate. The composite current collector may be formed by forming a metal material (aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer substrate (such as a substrate of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.).

[0131] As an example, the positive electrode active material may include at least one of the following materials: lithium phosphate, lithium transition metal oxide, and their respective modified compounds. However, this application is not limited to these materials, and other conventional materials that can be used as battery positive electrode active materials may also be used. These positive electrode active materials may be used alone or in combination of two or more. Examples of lithium phosphate may include, but are not limited to, at least one of lithium iron phosphate (such as LiFePO4 (also referred to as LFP)), lithium iron phosphate and carbon composites, lithium manganese phosphate (such as LiMnPO4), lithium manganese phosphate and carbon composites, lithium iron manganese phosphate, and lithium iron manganese phosphate and carbon composites. Examples of lithium transition metal oxide may include, but are not limited to, lithium cobalt oxide (such as LiCoO2), lithium nickel oxide (such as LiNiO2), lithium manganese oxide (such as LiMnO2, LiMn2O4), lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, and lithium nickel cobalt manganese oxide (such as LiNi). 1 / 3 Co 1 / 3 Mn 1 / 3 O2 (also known as NCM) 333 LiNi0.5 Co 0.2 Mn 0.3 O2 (also known as NCM) 523 LiNi 0.5 Co 0.25 Mn 0.25 O2 (also known as NCM) 211 LiNi 0.6 Co 0.2 Mn 0.2 O2 (also known as NCM) 622 LiNi 0.8 Co 0.1 Mn 0.1 O2 (also known as NCM) 811 ), lithium nickel cobalt aluminum oxide (such as LiNi) 0.8 Co 0.15 Al 0.05 At least one of O2 and its modified compounds. Modified compounds refer to substances obtained by modification methods such as doping or coating based on the above-mentioned substances.

[0132] In some embodiments, the positive electrode active material includes at least one of the compounds shown in formula (I) and formula (II);

[0133] Li 1+d [Ni x Co y Mn z M2 e O2 formula (I)

[0134] Wherein, 0.6≤x<1, 0<y<0.3, 0<z<0.3, -0.1<d<0.2, 0<e<0.2, x+y+z+e=1, and M2 includes one or more of Mg, Ca, Sb, Ce, Ti, Zr, Sr, Al, Zn, Mo, Y, W, Ta, F and B;

[0135] (LiMn p Fe 1-p-q M3 q PO4) Formula (II)

[0136] Wherein, 0.1≤p≤0.9, 0≤q≤0.05, and M3 includes one or more of V, Ti, Mg, Ni, Fe, Sn, and F.

[0137] When using the aforementioned cathode active materials with high transition metal content, the adverse effects of transition metal dissolution can be effectively reduced through the chelating effect of additives. Therefore, when using the aforementioned cathode active materials, the battery cell can simultaneously possess high energy density, cycle performance, and storage performance.

[0138] In some embodiments, the positive electrode material layer may optionally include a binder. For example, the binder may include one or more combinations of the following: polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), PVDF-tetrafluoroethylene-propylene terpolymer, PVDF-hexafluoropropylene-tetrafluoroethylene terpolymer, tetrafluoroethylene-hexafluoropropylene copolymer, and fluorinated acrylate resin.

[0139] In some embodiments, the positive electrode material layer may optionally include a conductive agent. For example, the conductive agent may include one or more combinations of the following: Super P, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.

[0140] In some embodiments, the positive electrode does not contain the additives, and the positive electrode can be prepared by dispersing the components of the above-mentioned positive electrode material layer, such as the positive electrode active material, optional conductive agent, binder and any other components, in a solvent (e.g., N-methylpyrrolidone) to form a positive electrode slurry; coating the positive electrode slurry onto the positive electrode current collector, and after drying, cold pressing and other processes, the positive electrode can be obtained.

[0141] In some embodiments, the positive electrode sheet contains the additives and can be prepared by dry mixing or wet mixing. In some embodiments, the positive electrode sheet can be prepared by the following method (wet mixing): dispersing the components of the above-mentioned positive electrode material layer, such as the positive electrode active material, the additives, optional conductive agents, optional binders, and any other components in a solvent (e.g., N-methylpyrrolidone), to form a positive electrode slurry; coating the positive electrode slurry onto a positive electrode current collector, and obtaining the positive electrode sheet after drying, cold pressing, and other processes.

[0142] In some embodiments, the positive electrode sheet can be prepared by the following method (dry mixing): the components of the above-mentioned positive electrode material layer, such as the positive electrode active material, the additive, optional conductive agent, optional binder and any other components, are mixed evenly, and then an appropriate amount of solvent (e.g., N-methylpyrrolidone) is added and stirred evenly to form a positive electrode slurry; the positive electrode slurry is coated on the positive electrode current collector, and after drying, cold pressing and other processes, the positive electrode sheet can be obtained.

[0143] [Negative electrode plate]

[0144] In some embodiments, the negative electrode sheet includes a negative current collector and a negative electrode material layer disposed on at least one surface of the negative current collector, the negative electrode material layer containing a negative electrode active material; when at least one of the positive electrode sheet and the separator in the battery cell contains the additive, the negative electrode material layer may not contain the additive.

[0145] In some embodiments, the negative electrode sheet includes a negative electrode current collector and a negative electrode material layer disposed on at least one surface of the negative electrode current collector, the negative electrode material layer comprising a negative electrode active material and the additive. Disposing of the additive on the surface of the negative electrode sheet can chelate the transition metal reaching the negative electrode sheet, minimizing its reduction on the negative electrode surface.

[0146] In some embodiments, the additive in the negative electrode material layer accounts for 0.2% to 1.0% by mass; for example, it can be about 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1.0%, etc.

[0147] When additives are used in negative electrode sheets, the above mass ratio is more conducive to chelating the transition metals before they are reduced, thus avoiding adverse effects on the SEI film.

[0148] In some embodiments, the negative electrode current collector may be a metal foil or a composite current collector. For example, copper foil may 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 may 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 a substrate of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.).

[0149] In some embodiments, the negative electrode material layer includes a negative electrode active material, which may be a negative electrode active material known in the art for use in batteries. For example, the negative electrode active material includes one or more combinations of the following: natural graphite, artificial graphite, mesophase microcarbon spheres (MCMB), hard carbon, soft carbon, silicon, silicon-carbon composites, Li-Sn alloys, Li-Sn-O alloys, Sn, SnO, SnO2, TiO2-Li4Ti5O 12 Li-Al alloys are used. However, this invention is not limited to these materials; other conventional materials that can be used as negative electrode active materials for lithium-ion batteries can also be used. These negative electrode active materials can be used alone or in combination of two or more.

[0150] In some embodiments, the negative electrode material layer may optionally include a binder. For example, the binder may include one or more combinations of the following: styrene-butadiene rubber (SBR), polyacrylic acid (PAA), sodium polyacrylate (PAAS), polyacrylamide (PAM), polyvinyl alcohol (PVA), sodium alginate (SA), polymethacrylic acid (PMAA), and carboxymethyl chitosan (CMCS).

[0151] In some embodiments, the negative electrode material layer may optionally include a conductive agent. For example, the conductive agent may include one or more combinations of the following: Super P, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.

[0152] In some embodiments, the negative electrode material layer may optionally include other additives. For example, other additives may be thickeners (such as sodium carboxymethyl cellulose (CMC-Na)).

[0153] In some embodiments, the negative electrode sheet does not contain the additives, and the negative electrode sheet can be prepared by dispersing the above-mentioned negative electrode material, such as negative electrode active material, optional conductive agent, binder and any other components in a solvent (e.g. deionized water) to form a negative electrode slurry; coating the negative electrode slurry onto the negative electrode current collector, and after drying, cold pressing and other processes, the negative electrode sheet can be obtained.

[0154] In some embodiments, the negative electrode sheet contains the additives and can be prepared by dry mixing or wet mixing. In some embodiments, the negative electrode sheet can be prepared by the following method (wet mixing): dispersing the components of the above-mentioned negative electrode material layer, such as the negative electrode active material, the additives, optional conductive agents, optional binders, and any other components in a solvent (e.g., deionized water), to form a negative electrode slurry; coating the negative electrode slurry onto a negative electrode current collector, and then obtaining the negative electrode sheet after drying, cold pressing, and other processes.

[0155] In some embodiments, the negative electrode sheet can be prepared by the following method (dry mixing): the components of the above-mentioned negative electrode material layer, such as the negative electrode active material, the additive, optional conductive agent, optional binder and any other components, are mixed evenly, and then an appropriate amount of solvent (e.g., deionized water) is added and stirred evenly to form a negative electrode slurry; the negative electrode slurry is coated on the negative electrode current collector, and after drying, cold pressing and other processes, the negative electrode sheet can be obtained.

[0156] [Isolation Component]

[0157] In some embodiments, the electrode assembly further includes a separator disposed between the positive electrode and the negative electrode; the separator may not contain the additive when at least one of the positive and negative electrodes in the battery cell contains the additive.

[0158] In some embodiments, the separator includes a base film and a film layer disposed on at least one surface of the base film, the film layer containing the additive. When the additive is disposed on the separator, it can chelate transition metal ions dissolved from the positive electrode to the electrolyte, thereby acting as an interceptor.

[0159] In some embodiments, the additive in the film layer accounts for 0.05% to 0.2% by mass; for example, it can be about 0.05%, 0.06%, 0.07%, 0.08%, 0.09%, 0.1%, 0.11%, 0.12%, 0.13%, 0.14%, 0.15%, 0.16%, 0.17%, 0.18%, 0.19%, 0.2%, etc.

[0160] When additives are used in separators, the above-mentioned mass percentages are more conducive to their chelation of transition metal ions in the electrolyte, thereby greatly preventing transition metal ions from shuttling to the negative electrode surface.

[0161] In some embodiments, the separator is a separator membrane. This application does not impose any particular limitation on the type of base membrane for the separator membrane; any known porous separator membrane with good chemical and mechanical stability can be selected.

[0162] As an example, the main material of the separator base film can be selected from at least one of glass fiber, non-woven fabric, polyethylene, polypropylene, polyvinylidene fluoride, and ceramic. The separator can be a single-layer film or a multi-layer composite film, without particular limitation. When the separator is a multi-layer composite film, the materials of each layer can be the same or different, without particular limitation. The separator can be a separate component located between the positive and negative electrodes, or it can be attached to the surfaces of the positive and negative electrodes.

[0163] In some embodiments, the membrane layer can be a coating disposed on the surface of the base membrane. For example, the membrane layer can be formed by coating the surface of the base membrane with an inorganic particle coating, an organic particle coating, or an organic / inorganic composite coating.

[0164] In some embodiments, the separator is a solid electrolyte. The solid electrolyte is disposed between the positive and negative electrodes, serving both to transport ions and to isolate the positive and negative electrodes.

[0165] [Electrolytes]

[0166] In some embodiments, the battery cell further includes an electrolyte; the electrolyte acts as a conductor of ions between the positive and negative electrodes. This application does not impose specific limitations on the type of electrolyte, which can be selected according to requirements. The electrolyte can be liquid, gel-like, or solid.

[0167] In some embodiments, the liquid electrolyte includes an electrolyte salt and a solvent.

[0168] In some embodiments, the electrolyte salt may be selected from at least one of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, lithium bis(fluorosulfonyl)imide, lithium bis(trifluoromethanesulfonyl)imide, lithium trifluoromethanesulfonate, lithium difluorophosphate, lithium difluorooxalate borate, lithium dioxalate borate, lithium difluorodioxalate phosphate, and lithium tetrafluorooxalate phosphate.

[0169] In some embodiments, the solvent may be selected from at least one of ethylene carbonate, propylene carbonate, methyl ethyl carbonate, diethyl carbonate, dimethyl carbonate, dipropyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, butyl carbonate, fluoroethylene carbonate, methyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate, ethyl butyrate, 1,4-butyrolactone, sulfolane, dimethyl sulfone, methyl ethyl sulfone, and diethyl sulfone. The solvent may also be an ether solvent. Ether solvents may include one or more of ethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, 1,3-dioxolane, tetrahydrofuran, methyl tetrahydrofuran, diphenyl ether, and crown ethers.

[0170] In some embodiments, the electrolyte may optionally include other functional additives. These functional additives may include negative electrode film-forming additives, positive electrode film-forming additives, and additives capable of improving certain properties of the battery cell, such as additives that improve the overcharge / fast charge performance of the battery cell, additives that improve the high-temperature performance of the battery cell, and additives that improve the low-temperature performance of the battery cell.

[0171] The gel electrolyte includes a polymer as a backbone network and can be used in conjunction with an ionic liquid—lithium salt.

[0172] Solid electrolytes include polymer solid electrolytes, inorganic solid electrolytes, and composite solid electrolytes.

[0173] As an example, the polymers of polymeric solid electrolytes may include polyethers (polyoxyethylene), polysiloxanes, polycarbonates, polyacrylonitrile, polyvinylidene fluoride, polymethyl methacrylate, monoionic polymers, polyionic liquids, cellulose, etc.

[0174] As an example, inorganic solid electrolytes can be one or more of the following: oxide solid electrolytes (crystalline perovskite, sodium superconducting ion conductor, garnet, amorphous LiPON thin film), sulfide solid electrolytes (crystalline lithium superconducting ion conductor (lithium-germanium-phosphorus-sulfur, sulfosilium-germanium), amorphous sulfides), halide solid electrolytes, nitride solid electrolytes, and hydride solid electrolytes.

[0175] As an example, composite solid electrolytes are formed by adding inorganic solid electrolyte fillers to polymer solid electrolytes.

[0176] [Structure of the electrode assembly]

[0177] The electrode assembly can be a wound structure, a stacked structure, or a hybrid structure of wound and stacked.

[0178] In some implementations, the electrode assembly is a wound structure. The positive and negative electrode sheets are wound into a wound structure.

[0179] In some implementations, the electrode assembly is a stacked structure.

[0180] As an example, multiple positive and negative electrode plates can be set, and multiple positive and multiple negative electrode plates can be stacked alternately.

[0181] As an example, multiple positive electrode sheets can be set, and negative electrode sheets are folded to form multiple stacked folded segments, with a positive electrode sheet sandwiched between adjacent folded segments.

[0182] As an example, both the positive and negative electrode sheets are folded to form multiple stacked folded segments.

[0183] As an example, multiple separators can be provided, each positioned between any adjacent positive or negative electrode plates.

[0184] As an example, the separator can be continuously arranged between any adjacent positive or negative electrode plates by folding or rolling.

[0185] In some embodiments, the electrode assembly can be cylindrical, flat, or polygonal, etc.

[0186] In some embodiments, the electrode assembly is provided with tabs that allow current to be drawn from the electrode assembly. The tabs include a positive tab and a negative tab.

[0187] [shell]

[0188] In some embodiments, the battery cell may include a casing. The casing may be a steel casing, an aluminum casing, a plastic casing (such as a polypropylene casing), a composite metal casing (such as a copper-aluminum composite casing), or an aluminum-plastic film, etc. In some embodiments, the casing may be a sealed structure or a non-sealed structure. As an example, when the casing is a non-sealed structure, the casing serves to protect the electrode assembly, and a sealing bag is included between the casing and the electrode assembly to encapsulate the electrode assembly and electrolyte. Specifically, the sealing bag may be a bag-shaped insulating component or an aluminum-plastic film. When the casing is a sealed structure, it is used to encapsulate components such as the electrode assembly and electrolyte.

[0189] As an example, the battery cell can be a cylindrical battery cell, a prismatic battery cell, a pouch battery cell, or a battery cell of other shapes. Prismatic battery cells include prismatic battery cells, blade-shaped battery cells, and multi-prismatic batteries, such as hexagonal prismatic batteries. This application does not impose any particular limitations. For example, Figure 1 This is an example of a square-shell battery cell 5.

[0190] In some implementations, refer to Figure 2 The outer casing includes an end cap 53 and a housing 51. The housing 51 has an opening, and the end cap 53 covers the opening. The housing 51 may have one or more openings. The end cap 53 may also have one or more. The positive electrode, negative electrode, and separator may be formed into an electrode assembly 52 by a winding process or a stacking process. The electrode assembly 52 is encapsulated within a receiving cavity formed by the housing 51 and the end cap 53. The electrolyte is immersed in the electrode assembly 52.

[0191] [Electrode terminals]

[0192] In some embodiments, at least one electrode terminal is provided on the housing, and the electrode terminal is electrically connected to the tab. The electrode terminal can be directly connected to the tab, or it can be indirectly connected to the tab through a current collector. The electrode terminal can be provided on the end cap or on the housing.

[0193] [Pressure relief mechanism]

[0194] In some embodiments, a pressure relief mechanism is provided on the casing. The pressure relief mechanism is used to release the internal gas of the battery cell.

[0195] As an example, the internal pressure or temperature of a battery cell is actuated to release the internal pressure or temperature when it reaches a predetermined threshold. When the internal pressure or temperature of the battery cell reaches the predetermined threshold, the pressure relief mechanism is activated or a weak structure in the pressure relief mechanism is broken, thereby forming an opening or channel for the internal pressure or temperature to be released. The threshold design varies depending on the design requirements. The threshold may depend on the materials of one or more of the positive electrode, negative electrode, electrolyte, and separator in the battery cell.

[0196] As an example, the pressure relief mechanism can be integrally molded with the housing.

[0197] As an example, the pressure relief mechanism can also be separately installed and connected to the housing.

[0198] The term "actuation" as used in this application refers to the activation or actuation of the pressure relief mechanism to a certain state, thereby releasing the internal pressure and temperature of the battery cell. The actions of the pressure relief mechanism may include, but are not limited to: movement of components within the mechanism to form an exhaust channel, rupture, breakage, tearing, or opening of at least a portion of the mechanism, etc. When the pressure relief mechanism is activated, the high-temperature, high-pressure substances inside the battery cell are discharged as waste from the activated portion. This method allows for pressure and temperature relief of the battery cell under controllable pressure or temperature, thereby preventing potentially more serious accidents.

[0199] In some embodiments, when the housing is a non-sealed structure, the pressure relief mechanism can be configured as a through hole for venting gas inside the battery cell.

[0200] The emissions from battery cells mentioned in this application include, but are not limited to: electrolyte, dissolved or split positive and negative electrode plates, fragments of separators, high-temperature and high-pressure gases generated by the reaction, flames, etc.

[0201] Battery device

[0202] 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 connected in series, parallel, or mixed connections via a busbar.

[0203] In some embodiments, a battery cell assembly is typically formed by arranging multiple battery cells.

[0204] 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. Figure 3 This is battery module 4 as an example. (See reference...) Figure 3 In the battery module 4, multiple battery cells 5 can be arranged sequentially along the length of the battery module 4. Of course, they can also be arranged in any other way.

[0205] In some embodiments, the battery device may be a battery pack, which includes a housing and one or more individual battery cells housed within the housing.

[0206] 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. Figure 4 and Figure 5 This is battery pack 1 as an example. (See reference...) Figure 4 and Figure 5 The battery pack 1 may include a housing and multiple battery modules 4 disposed within the housing. The housing includes an upper housing 2 and a lower housing 3, with the upper housing 2 covering the lower housing 3 to form a closed space for accommodating the battery modules 4. The multiple battery modules 4 can be arranged in any manner within the battery pack.

[0207] As an example, battery cell assemblies can also be housed in a housing by directly fixing multiple battery cells to the housing.

[0208] 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.

[0209] 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.

[0210] 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.

[0211] Electrical appliances

[0212] 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. Figure 6 This is an example of an electrical device. The electrical device could be a pure electric vehicle, a hybrid electric vehicle, or a plug-in hybrid electric vehicle, etc.

[0213] Example 1

[0214] This embodiment provides a lithium-ion battery, the preparation method of which is as follows:

[0215] 1. Positive electrode plate

[0216] The positive electrode active material (LiNi) 0.9 Co 0.05 Mn 0.05O2), conductive agent (super carbon black), and binder (PVDF) are mixed in a mass ratio of 98:1:1. An appropriate amount of NMP (N-methylpyrrolidone) is added, and the mixture is stirred and mixed. Then, it undergoes wetting, kneading, and dispersion treatments to obtain a positive electrode slurry for forming the positive electrode material layer. The prepared positive electrode slurry is coated onto a positive electrode current collector aluminum foil, and then dried in an oven at 110℃, controlling the water content to be less than 150ppm, to obtain the positive electrode sheet.

[0217] 2. Negative electrode plate

[0218] The negative electrode active material graphite (artificial graphite:natural graphite = 6:4 (mass ratio)), binder (polystyrene-butadiene rubber SBR), dispersant (sodium carboxymethyl cellulose CMC), conductive agent (SP-Li), and additive (lithium aminotrimethylene phosphate AMTP-6Li) were mixed in a mass ratio of 95:2:1.2:1.5:0.3. A certain amount of deionized water was added to control the water content, resulting in a negative electrode slurry with a solid content of 55% for forming the negative electrode material layer. The negative electrode slurry was coated on the surface of the negative electrode current collector copper foil, rolled, and vacuum dried overnight at 110°C to obtain the negative electrode sheet.

[0219] 3. Separating membrane

[0220] A polyethylene film with a thickness of 13μm is used.

[0221] 4. Electrolyte

[0222] The solvent is ethylene carbonate (EC), diethyl carbonate (DEC), and dimethyl carbonate (DMC) in a volume ratio of 1:1:1. The lithium salt is LiPF6. The lithium salt and solvent are mixed evenly to make the lithium salt concentration 1 mol / L to obtain the electrolyte.

[0223] 5. Battery assembly

[0224] The electrodes are arranged in the following order: separator - negative electrode sheet - separator - positive electrode sheet. One end of the positive electrode sheet, negative electrode sheet, and two separators is fixed to the discharge roller, and the other end is stacked together and fixed to the winding shaft. The winding shaft is rotated by a motor to wind the positive electrode sheet, negative electrode sheet, and two separators to obtain the electrode assembly. The electrode assembly is placed in the battery casing, dried, and then injected with electrolyte. After vacuum sealing, settling, formation, and shaping, a lithium-ion battery is obtained.

[0225] Perform the following tests and record the results in Table 1.

[0226] (1) 2C capacity retention %

[0227] The lithium-ion battery was placed in the electrochemical test channel and charged and discharged at a rate of 0.33C at room temperature (25°C) within a voltage range of 2.8-4.25V. It was charged to 4.25V and then discharged at 0.33C; the resulting capacity is recorded as C0. Similarly, at 25°C, it was charged at a rate of 0.33C to 4.25V and then discharged at a rate of 2C; the resulting capacity is recorded as C1. The 2C capacity retention rate is calculated using the formula: 2C capacity retention rate = C1 / C0 × 100%.

[0228] (2) Capacity retention rate (%) after 100 days of storage at 60℃

[0229] The lithium-ion battery was placed in the electrochemical test channel and fully charged to 4.25V at 0.33C current at 60℃, then fully discharged to 2.8V at 0.33C current, and the capacity C0 was recorded. After 20 days, the battery was fully charged and discharged under the same conditions as when the capacity C0 was tested, and the capacity C1 was recorded. After another 20 days, the battery was fully charged and discharged once, and the capacity C2 was recorded. The above steps were repeated, and the discharge capacity from C0 to C3 was read. The storage capacity retention rate after 60 days can be calculated by the formula: Capacity retention rate = C3 / C0 × 100%.

[0230] Example 2

[0231] Except for the additive being lithium p-phenol-2-ethyl diphosphate lithium Ph-O-5Li (structural formula shown below), the preparation and testing were carried out according to the same steps as in Example 1, and the results are shown in Table 1.

[0232]

[0233] Example 3

[0234] Except for the additive being lithium hydroxyethylidene diphosphate HEDP-4Li (structural formula shown below), the preparation and testing were carried out according to the same steps as in Example 1, and the results are shown in Table 1.

[0235]

[0236] Example 4

[0237] Except for the additive being aminotrimethylene zinc phosphate ATMP-3Zn (structural formula shown below), it was prepared according to the same steps as in Example 1, and the 2C capacity retention rate and storage capacity retention rate were tested. The results are shown in Table 1.

[0238]

[0239] Example 5

[0240] Except for the additive being sodium aminotrimethylene phosphate (ATMP-6Na) (structural formula shown below), the preparation and testing were carried out according to the same steps as in Example 1, and the results are shown in Table 1.

[0241]

[0242] Example 6

[0243] Except for the additive being aminotrimethylene ammonium phosphate ATMP-6NH4 (structural formula shown below), the preparation and testing were carried out according to the same steps as in Example 1, and the results are shown in Table 1.

[0244]

[0245] Comparative Example 1

[0246] Except for the absence of additives in the negative electrode sheet, the preparation and testing were carried out in the same manner as in Example 1, and the results are shown in Table 1.

[0247] Comparative Example 2

[0248] Except for the additive being polyacrylonitrile (PAN, Mw = 10W), the preparation and testing were carried out in the same manner as in Example 1, and the results are shown in Table 1.

[0249] Comparative Example 3

[0250] Except for the additive being ammonium dihydrogen phosphate, the preparation and testing were carried out in the same manner as in Example 1, and the results are shown in Table 1.

[0251] Comparative Example 4

[0252] Except for the additive being disulfiram (TETD), the preparation and testing were carried out in the same manner as in Example 1, and the results are shown in Table 1.

[0253] Table 1

[0254] additive 2C Capacity Retention Capacity retention rate after 100 days of storage at 60℃ Example 1 AMTP-6Li 99.4％ 92.4％ Example 2 Ph-O-5Li 99.2％ 92.3％ Example 3 HEDP-4Li 99.3％ 92.3％ Example 4 ATMP-3Zn 99.3％ 92.4％ Example 5 ATMP-6Na 99.3％ 92.3％ Example 6 <![CDATA[ATMP-6NH4]]> 99.4％ 92.4％ Comparative Example 1 none 98.7％ 90.3％ Comparative Example 2 Polyacrylonitrile 98.9％ 91.2％ Comparative Example 3 Ammonium dihydrogen phosphate 99.1％ 91.8％ Comparative Example 4 Disulfiram 99.0％ 91.6％

[0255] As shown in Table 1, compared with the use of no additives (Comparative Example 1) or the use of other types of additives (Comparative Examples 2-4), Examples 1-6 of this application significantly improved the capacity retention of the battery under cycling and storage conditions.

[0256] Examples 7-9

[0257] Except for the mass percentage of the additive in the negative electrode material layer shown in Table 2, the preparation and testing were carried out in the same manner as in Example 1, and the results are shown in Table 2.

[0258] Table 2

[0259]

[0260] Examples 10-12

[0261] Except for the positive electrode active material shown in Table 3, the preparation and testing were carried out in the same manner as in Example 1, and the results are shown in Table 3.

[0262] Table 3

[0263]

[0264]

[0265] As shown in Table 3, using different positive electrode active materials can improve the capacity retention of the battery under cycling and high-temperature storage conditions.

[0266] Example 13

[0267] As described below, except that the additive accounts for 0.2% of the mass of the positive electrode material layer and the negative electrode does not contain any additives, the preparation and testing were carried out in the same manner as in Example 1, and the results are shown in Table 4.

[0268] Positive electrode preparation: The positive electrode active material (LiNi) is prepared... 0.9 Co 0.05 Mn 0.05 O2), conductive agent (super carbon black), binder (PVDF), and lithium aminotrimethylene phosphonate (ATMP-6Li) are mixed in a mass ratio of 97.8:1:1:0.2. An appropriate amount of NMP (N-methylpyrrolidone) is added, and the mixture is stirred and mixed, then wetted, kneaded, and dispersed to obtain a positive electrode slurry. The prepared positive electrode slurry is coated onto a positive electrode current collector aluminum foil, and then dried in an oven at 110℃, controlling the water content to be less than 150ppm, to obtain the positive electrode sheet.

[0269] Preparation of negative electrode material: The negative electrode active material graphite (artificial graphite: natural graphite = 6:4 (mass ratio)), binder (polystyrene-butadiene rubber SBR), dispersant (sodium carboxymethyl cellulose CMC), and conductive agent (SP-Li) are mixed in a mass ratio of 95:2:1.5:1.5. A certain amount of deionized water is added to control the water content and obtain a negative electrode slurry with a solid content of 55%. The negative electrode slurry is coated on the surface of the negative electrode current collector copper foil, rolled, and vacuum dried overnight at 110°C to obtain the negative electrode sheet.

[0270] Example 14

[0271] Except that the additive used was lithium ethylenediaminetetramethylenephosphonate (EDTMP-8Li) and the content of the additive in the positive electrode material layer was 0.5%, the preparation and testing were carried out in the same manner as in Example 13, and the results are shown in Table 4.

[0272] Example 15

[0273] Except for the additive content in the positive electrode material layer being 1.0%, the preparation and testing were carried out in the same manner as in Example 13, and the results are shown in Table 4.

[0274] Table 4

[0275]

[0276] As shown in Table 4, when additives are applied to the positive electrode, they can improve the capacity retention rate during cycling and storage.

[0277] Example 16

[0278] Except for the preparation of the diaphragm according to the following method and the preparation of the negative electrode sheet as in Example 13, the other preparations and tests were carried out in the same manner as in Example 1, and the results are shown in Table 5.

[0279] Preparation of diaphragm coating slurry: Take lithium aminotrimethylene phosphonate (ATMP-6Li) powder, aluminum oxide, and sodium carboxymethyl cellulose as additives and mix them in a ratio of 50:40:10. Control the mass ratio of water and mix them. Stir and disperse at 500 rpm / min to obtain the coating slurry. The solid content of the coating slurry is 30%.

[0280] Membrane preparation: A coating slurry was applied to one side of a polyethylene membrane with a thickness of 7 μm, serving as the base membrane. The coating slurry was applied in an amount of 50 × 100 mm. 2 2 mg of ATMP-6Li was coated onto the surface of the base membrane and dried at 60°C to form a membrane layer, thus preparing the diaphragm. The mass percentage of the additive ATMP-6Li in the membrane layer of the diaphragm was 0.05%.

[0281] Example 17

[0282] Except that the mass percentage of additives in the film layer was 0.1%, the preparation and testing were carried out in the same manner as in Example 16, and the results are shown in Table 5.

[0283] Example 18

[0284] Except for the fact that the mass percentage of additives in the film layer is 0.2%, the preparation and testing were carried out in the same manner as in Example 16, and the results are shown in Table 5.

[0285] Table 5

[0286]

[0287]

[0288] The above description is merely a preferred embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A battery cell, characterized in that, Includes positive electrode, separator, and negative electrode; At least one of the positive electrode, the separator, and the negative electrode contains an additive; The additive is an organic small molecule, organic polymer, or organic salt having a functional group A; The functional group A includes at least two chelating groups, each of which is independently selected from a phosphate group or a phosphate group.

2. The battery cell as described in claim 1, characterized in that, The additive contains at least two functional groups A.

3. The battery cell as described in claim 1 or 2, characterized in that, In the functional group A, each chelating group is directly or via an alkylene group coupled to the same atom X, where X is selected from O, N, and S.

4. The battery cell according to any one of claims 1 to 3, characterized in that, The phosphate group includes at least one of the following: lithium phosphate group, sodium phosphate group, potassium phosphate group, ammonium phosphate group, and zinc phosphate group.

5. The battery cell according to any one of claims 1 to 4, characterized in that, The functional group A is -X-((CH2)). n -PO3M1 a H b ) c Where X is selected from O, N, and S, n is an integer from 0 to 2, and M1 is selected from Li cations with valence state m. + Na + K + NH4 + Zn 2+ One of them, (a*m)+b=2, c=2 or 3.

6. The battery cell according to any one of claims 1 to 5, characterized in that, The additive includes at least one of the following: hydroxyethylidene diphosphate or a salt thereof, aminotrimethylene phosphate or a salt thereof, ethylenediaminetetramethylenephosphonic acid or a salt thereof, hexamethylenediaminetetramethylenephosphonic acid or a salt thereof, bis(1,6-hexyltriaminepentimethylenephosphonic acid or a salt thereof, and lithium p-phenol-2-ethyldiphosphate.

7. The battery cell according to any one of claims 1 to 6, characterized in that, The positive electrode sheet includes a positive current collector and a positive electrode material layer disposed on at least one surface of the positive current collector, wherein the positive electrode material layer includes a positive electrode active material; The positive electrode active material includes at least one of the compounds shown in formula (I) and formula (II); Li 1+d [Ni x Co y Mn z M2 e O₂ formula (I) Wherein, 0.6≤x<1, 0<y<0.3, 0<z<0.3, -0.1<d<0.2, 0<e<0.2, x+y+z+e=1, and M2 includes one or more of Mg, Ca, Sb, Ce, Ti, Zr, Sr, Al, Zn, Mo, Y, W, Ta, F and B; (LiMn p Fe 1-p-q M3 q (PO4) formula (II) Wherein, 0.1≤p≤0.9, 0≤q≤0.05, and M3 includes one or more of V, Ti, Mg, Ni, Fe, Sn, and F.

8. The battery cell according to any one of claims 1 to 7, characterized in that, The positive electrode sheet includes a positive current collector and a positive electrode material layer disposed on at least one surface of the positive current collector, the positive electrode material layer comprising a positive electrode active material and the additive; wherein the additive in the positive electrode material layer comprises 0.2% to 1.0% by mass; and / or, The negative electrode sheet includes a negative electrode current collector and a negative electrode material layer disposed on at least one surface of the negative electrode current collector. The negative electrode material layer includes a negative electrode active material and the additive; in the negative electrode material layer, the mass percentage of the additive is 0.2% to 1.0%; and / or, The separator includes a base film and a film layer disposed on at least one surface of the base film, the film layer containing the additive; wherein the mass percentage of the additive in the film layer is 0.05% to 0.2%.

9. A positive electrode sheet, characterized in that, The positive electrode sheet includes a positive current collector and a positive electrode material layer disposed on at least one surface of the positive current collector, the positive electrode material layer comprising a positive electrode active material and additives; The additive is an organic small molecule, organic polymer, or organic salt having a functional group A; The functional group A includes at least two chelating groups, each of which is independently selected from a phosphate group or a phosphate group.

10. The positive electrode sheet as described in claim 9, characterized in that, In the positive electrode material layer, the additive accounts for 0.2% to 1.0% of the total mass.

11. The positive electrode sheet as described in claim 9 or 10, characterized in that, The additive contains at least two functional groups A.

12. The positive electrode sheet according to any one of claims 9 to 11, characterized in that, In the functional group A, each chelating group is directly or via an alkylene group coupled to the same atom X, where X is selected from O, N, and S.

13. The positive electrode sheet as described in any one of claims 9 to 12, characterized in that, The phosphate group includes at least one of the following: lithium phosphate group, sodium phosphate group, potassium phosphate group, ammonium phosphate group, and zinc phosphate group.

14. The positive electrode sheet according to any one of claims 9 to 13, characterized in that, The functional group A is -X-((CH2)). n -PO3M1 a H b ) c Where X is selected from O, N, and S, n is an integer from 0 to 2, and M1 is selected from Li cations with valence state m. + Na + K + NH4 + Zn 2+ One of them, (a*m)+b=2, c=2 or 3.

15. The positive electrode sheet according to any one of claims 9 to 14, characterized in that, The additive includes at least one of the following: hydroxyethylidene diphosphate or a salt thereof, aminotrimethylene phosphate or a salt thereof, ethylenediaminetetramethylenephosphonic acid or a salt thereof, hexamethylenediaminetetramethylenephosphonic acid or a salt thereof, bis(1,6-hexyltriaminepentimethylenephosphonic acid or a salt thereof, and lithium p-phenol-2-ethyldiphosphate.

16. The positive electrode sheet according to any one of claims 9 to 15, characterized in that, The positive electrode active material includes at least one of the compounds shown in formula (I) and formula (II); Li 1+d [Ni x Co y Mn z M2 e O₂ type (I) Wherein, 0.6≤x<1, 0<y<0.3, 0<z<0.3, -0.1<d<0.2, 0<e<0.2, x+y+z+e=1, and M2 includes one or more of Mg, Ca, Sb, Ce, Ti, Zr, Sr, Al, Zn, Mo, Y, W, Ta, F and B; (LiMn p Fe 1-p-q M3 q (PO4) formula (II) Wherein, 0.1≤p≤0.9, 0≤q≤0.05, and M3 includes one or more of V, Ti, Mg, Ni, Fe, Sn, and F.

17. A method for preparing a positive electrode sheet, characterized in that, The preparation method includes, Provides positive current collector; A positive electrode material layer is disposed on at least one surface of the positive electrode current collector, the positive electrode material layer comprising a positive electrode active material and additives; The additive is an organic small molecule, organic polymer, or organic salt having a functional group A; The functional group A includes at least two chelating groups, each of which is independently selected from a phosphate group or a phosphate group.

18. A negative electrode sheet, characterized in that, The negative electrode sheet includes a negative electrode current collector and a negative electrode material layer disposed on at least one surface of the negative electrode current collector, wherein the negative electrode material layer includes a negative electrode active material and additives; The additive is an organic small molecule, organic polymer, or organic salt having a functional group A; The functional group A includes at least two chelating groups, each of which is independently selected from a phosphate group or a phosphate group.

19. The negative electrode sheet as described in claim 18, characterized in that, In the negative electrode material layer, the additive accounts for 0.2% to 1.0% of the total mass.

20. The negative electrode sheet as described in claim 18 or 19, characterized in that, The additive contains at least two functional groups A.

21. The negative electrode sheet as described in any one of claims 18 to 20, characterized in that, In the functional group A, each chelating group is directly or via an alkylene group coupled to the same atom X, where X is selected from O, N, and S.

22. The negative electrode sheet as described in any one of claims 18 to 21, characterized in that, The phosphate group includes at least one of the following: lithium phosphate group, sodium phosphate group, potassium phosphate group, ammonium phosphate group, and zinc phosphate group.

23. The negative electrode sheet as described in any one of claims 18 to 22, characterized in that, The functional group A is -X-((CH2)). n -PO3M1 a H b ) c Where X is selected from O, N, and S, n is an integer from 0 to 2, and M1 is selected from Li cations with valence state m. + Na + K + NH4 + Zn 2+ One of them, (a*m)+b=2, c=2 or 3.

24. The positive electrode sheet as described in any one of claims 18 to 23, characterized in that, The additive includes at least one of the following: hydroxyethylidene diphosphate or a salt thereof, aminotrimethylene phosphate or a salt thereof, ethylenediaminetetramethylenephosphonic acid or a salt thereof, hexamethylenediaminetetramethylenephosphonic acid or a salt thereof, bis(1,6-hexyltriaminepentimethylenephosphonic acid or a salt thereof, and lithium p-phenol-2-ethyldiphosphate.

25. A method for preparing a negative electrode sheet, characterized in that, The preparation method includes, Provide negative electrode current collector; A negative electrode material layer is disposed on at least one surface of the negative electrode current collector, the negative electrode material layer comprising a negative electrode active material and additives; The additive is an organic small molecule, organic polymer, or organic salt having a functional group A; The functional group A includes at least two chelating groups, each of which is independently selected from a phosphate group or a phosphate group.

26. A separating membrane, characterized in that, The separator includes a base film and a film layer disposed on at least one surface of the base film, the film layer containing additives; The additive is an organic small molecule, organic polymer, or organic salt having a functional group A; The functional group A includes at least two chelating groups, each of which is independently selected from a phosphate group or a phosphate group.

27. The separator membrane as claimed in claim 26, characterized in that, In the membrane layer, the additive accounts for 0.05% to 0.2% of the total mass.

28. The separator as claimed in claim 26 or 27, characterized in that, The additive contains at least two functional groups A.

29. The separator membrane according to any one of claims 26 to 28, characterized in that, In the functional group A, each chelating group is directly or via an alkylene group coupled to the same atom X, where X is selected from O, N, and S.

30. The separator membrane according to any one of claims 26 to 29, characterized in that, The phosphate group includes at least one of the following: lithium phosphate group, sodium phosphate group, potassium phosphate group, ammonium phosphate group, and zinc phosphate group.

31. The separator membrane according to any one of claims 26 to 30, characterized in that, The functional group A is -X-((CH2)). n -PO3M1 a H b ) c Where X is selected from O, N, and S, n is an integer from 0 to 2, and M1 is selected from Li cations with valence state m. + Na + K + NH4 + Zn 2+ One of them, (a*m)+b=2, c=2 or 3.

32. The separator membrane according to any one of claims 26 to 31, characterized in that, The additive includes at least one of the following: hydroxyethylidene diphosphate or a salt thereof, aminotrimethylene phosphate or a salt thereof, ethylenediaminetetramethylenephosphonic acid or a salt thereof, hexamethylenediaminetetramethylenephosphonic acid or a salt thereof, bis(1,6-hexyltriaminepentimethylenephosphonic acid or a salt thereof, and lithium p-phenol-2-ethyldiphosphate.

33. A method for preparing a separating membrane, characterized in that, The preparation method includes, Provide base film; A film layer is disposed on at least one surface of the base film, the film layer comprising an additive; the additive is an organic small molecule, organic polymer, or organic salt having a functional group A; The functional group A includes at least two chelating groups, each of which is independently selected from a phosphate group or a phosphate group.

34. A battery device, characterized in that, The battery cell includes any one of claims 1 to 8, the positive electrode sheet according to any one of claims 9 to 16, the positive electrode sheet prepared by the preparation method according to claim 17, the negative electrode sheet according to any one of claims 18 to 24, the negative electrode sheet prepared by the preparation method according to claim 25, the separator according to any one of claims 26 to 32, or the separator prepared by the preparation method according to claim 33.

35. An electrical appliance, characterized in that, The battery cell includes any one of claims 1 to 8, the positive electrode sheet according to any one of claims 9 to 16, the positive electrode sheet prepared by the preparation method according to claim 17, the negative electrode sheet according to any one of claims 18 to 24, the negative electrode sheet prepared by the preparation method according to claim 25, the separator according to any one of claims 26 to 32, the separator prepared by the preparation method according to claim 33, or the battery device according to claim 34.

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