Lithium-ion battery

Abstract

Lithium-ion battery, characterized in that the battery comprises a positive electrode plate, a negative electrode plate and an electrolyte solution, wherein the positive electrode plate comprises, in its thickness direction, a first surface and a second surface arranged opposite to each other, wherein the first surface is provided with a plurality of first projections arranged at a distance from each other and the second surface is provided with a plurality of first depressions, wherein the height of the first projection is denoted by H in µm and the diameter of the first projection is denoted by R in mm, and wherein for H and R: 0.2 ≤ H / R ≤ 80; wherein the electrolyte solution comprises a carboxylic acid ester, the mass fraction of which with respect to the total mass of the electrolyte solution is denoted by A in %, and wherein A is: 10 ≤ A ≤ 80; wherein the electrolyte solution comprises a nitrile compound whose mass fraction with respect to the total mass of the electrolyte solution is denoted by B in % and wherein B satisfies the following: 3 ≤ B ≤ 30.

Description

Technical FieldThe present application relates to the technical field of lithium ion batteries, and more particularly relates to a lithium ion battery.Prior ArtLithium batteries have become an indispensable constituent for everyday life and provide durable and high performance for smartphones, laptops, electric cars, etc. In work, learning, and entertainment, the lithium batteries greatly improve quality of life because of their convenience and reliability. As technologies progress, fast charging technology appears, significantly shortening charging time and meeting requirements of fast life modern life.However, in fast charging, the phenomenon of lithium deposition is a problem to be solved urgent. When lithium ions are rapidly discharged from a positive electrode and attempt to be deposited into a negative electrode, this results in the deposition of the lithium ions on the surface of the negative electrode and hence in the formation of metallic lithium when the rate of deposition into the negative electrode is below the charging rate or when the surface of the electrode is saturated with lithium deposited. This can not only shorten the life of the battery, but also lead to safety problems such as overheating, expansion or even burning of the battery, etc. Therefore, it becomes an important issue in the development of the technology for the lithium batteries, such as the phenomenon of lithium deposition while increasing the charging speed is effectively controlled and avoided.Disclosure of the ApplicationAn object of the present application is to overcome the above problems in the prior art and to provide a lithium ion battery in which a positive electrode plate is provided with protrusions and recesses. By controlling the ratio of the height of the protrusion to the diameter of the protrusion, uneven textures of appropriate size can be formed on the surface of the positive electrode plate, so that the liquid storage space of the electrode plate is enlarged, the transmission path for lithium ions is optimized, and the rapid charging performance of the battery is improved. At the same time, a carboxylic acid ester and a nitrile compound introduced into an electrolyte solution have a low viscosity, so that conductivity is increased, the uniform transfer rate of lithium ions is accelerated, the problem of the possible uneven local transfer rate of lithium ions is effectively alleviated by providing the electrode plate with protrusions and recesses, the lithium deposition is reduced, and the cycle stability of the battery is improved.In order to achieve the above object, the present application provides a lithium ion battery. The battery comprises a positive electrode plate, a negative electrode plate and an electrolyte solution, wherein the positive electrode plate comprises, in its thickness direction, a first surface and a second surface arranged opposite to each other, wherein the first surface is provided with a plurality of first protrusions arranged spaced apart from each other, and the second surface is provided with a plurality of first recesses, respectively, wherein the height of the first protrusion is denoted by H in μm and the diameter of the first protrusion is denoted by R in mm, and wherein H and R are denoted: 0.2≤H / R≤80; wherein the electrolyte solution comprises a carboxylic acid ester whose mass proportion with respect to the total mass of the electrolyte solution is denoted by A in %, and wherein A is denoted: 10≤A≤80; wherein the electrolyte solution comprises a nitrile compound whose mass fraction with respect to the total mass of the electrolyte solution is denoted as B in %, and wherein the following applies to B: 3≤B≤30.The technical solutions of the present application have the following favorable effects:In the lithium ion battery according to the present application, it is arranged that, by adjusting the ratio of the height of the protrusion to the diameter of the protrusion, uneven textures of an appropriate size are formed on the surface of the positive electrode plate, so that a liquid storage space of the electrode plate is enlarged, a transmission path for lithium ions is optimized, and rapid charging performance is improved. At the same time, by the carboxylic acid ester and the nitrile compound introduced into an electrolyte solution, it is realized that the viscosity is reduced, the conductivity is increased, the uniform transfer rate of lithium ions is accelerated, the problem of the possible uneven local transfer rate of lithium ions is effectively alleviated by providing the electrode plate with protrusions and recesses, the lithium deposition is reduced, and the cycle stability of the battery is improved.The endpoints and any values of the ranges disclosed herein are not limited to these exact ranges or values, and rather, these ranges or values are to be understood to include values near these ranges or values. For a range of values, endpoint values of respective ranges are combined with each other, endpoint values of respective ranges with individual point values, and individual point values are combined with each other, so that one or more new value range(s) can / can be obtained, which is / are considered to be expressly disclosed herein. Herein, the data ranges include their endpoints unless otherwise specified.Brief Description of the FiguresFIG. 1 is a schematic structural diagram of a positive electrode plate according to an embodiment of the present application.List of reference numbers: 1. positive electrode current collector; 2. positive electrode active material; 3. second surface; 4. first surface; 5. first depression; 6.first elevation.DETAILED EMBODIMENTSThe detailed embodiments of the present application are described in more detail below. It should be understood that the detailed embodiments herein are only intended to describe and explain the present application without limiting it.Unless defined otherwise, all of the scientific and technical terms used in the present application have the same meanings as those generally understood by those skilled in the relevant technical field of the present application.In the present application, terms "battery", "lithium battery", "lithium ion battery", and "lithium ion secondary battery" have the same meaning and all refer to the lithium ion secondary battery, and usually include an electrode assembly such as a positive electrode plate, a negative electrode plate, and a separator, a container (i.e., a case) for accommodating the electrode assembly, and an electrolyte solution.In the present application, the term "C4-C10carboxylic acid ester" refers to a carboxylic acid ester having, in the molecule, a hydrocarbon group (i.e., a carbon chain connected to a carboxy group) having 4 to 10 carbon atoms.In the present application, the term "fluorinated carboxylic ester" refers to a compound formed by substituting a fluorine atom for a hydrogen atom in a carboxylic ester molecule, wherein a fluorinated carboxylic ester referred to as a fluorinated derivative of the C4-C10carboxylic ester is a compound formed by substituting a fluorine atom for a hydrogen atom in the C4-C10carboxylic ester.In the present application, the term "C2-C10mononitrile compound and fluorinated derivatives thereof" refers to nitrile compounds containing only a cyano group and 2 to 10 carbon atoms. "The fluorinated derivative of the C2-C10mononitrile compound" refers to a compound formed by substituting a fluorine atom for a hydrogen atom in a hydrocarbon group of a mononitrile compound having 2 to 10 carbon atoms. Here, the mononitrile compound and the fluorinated derivatives thereof include both a saturated mononitrile compound and the fluorinated derivatives thereof and an unsaturated mononitrile compound and the fluorinated derivatives thereof.In the present application, the term "C2-C10polynitrile compound and the fluorinated derivatives thereof" refers to nitrile compounds containing two or more cyano groups and 2 to 10 carbon atoms. "The fluorinated derivative of the C2-C10polynitrile compound" refers to a compound formed by substituting a fluorine atom for a hydrogen atom in a hydrocarbon group of a polynitrile compound having 2 to 10 carbon atoms. Here, the polynitrile compound and the fluorinated derivatives thereof include both a saturated polynitrile compound and the fluorinated derivatives thereof and an unsaturated polynitrile compound and the fluorinated derivatives thereof.The present application provides a lithium ion battery. The battery comprises a positive electrode plate, a negative electrode plate and an electrolyte solution, wherein the positive electrode plate comprises, in its thickness direction, a first surface and a second surface arranged opposite to each other, wherein the first surface is provided with a plurality of first protrusions arranged spaced apart from each other, and the second surface is provided with a plurality of first recesses, respectively, wherein the height of the first protrusion is denoted by H in μm and the diameter of the first protrusion is denoted by R in mm, and wherein H and R are denoted: 0.2≤H / R≤80; wherein the electrolyte solution comprises a carboxylic acid ester whose mass proportion with respect to the total mass of the electrolyte solution is denoted by A in %, and wherein A is denoted: 10≤A≤80; wherein the electrolyte solution comprises a nitrile compound whose mass fraction with respect to the total mass of the electrolyte solution is denoted as B in %, and wherein the following applies to B: 3≤B≤30.By way of example, the value for H / R can be, for example, 0.2, 0.3, 0.4, 0.5, 0.75, 1, 3, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80 or any point value in a range formed by any two of the above point values.By way of example, in the electrolyte solution, the proportion by mass of the carboxylic ester A in % may be, for example, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80% or any point value in a range formed by any two of the above points values.For example, in the electrolyte solution, the mass proportion of the nitrile compound B in % may be, for example, 3%, 5%, 8%, 10%, 12%, 14%, 16%, 18%, 20%, 22%, 248%, 26%, 28%, 30% or any point value in a range formed by any two of the above points values.It should be noted that when calculating the value of formula H / R, H and R are substituted by corresponding values in the formula without considering the conversion of their units. For example, when H=20 μm and R=2 mm, H / R=20 / 2=10.When the battery is charged or discharged, the incorporation or removal of the lithium ions into or from the electrode plate results in a large volume change within the battery. This change in volume results in the surface of the electrode being subjected to a large pressing force, and the surface of the electrode being subjected to a larger pressing force and deforming more pronely at a rounded position of a winding structure for a winding battery. This easily leads to insufficient electrolyte solution at the rounded portion, and thus a transmission channel for the lithium ions is limited, so that the lithium ions cannot easily reach and be incorporated into the surface of the negative electrode, thus leading to safety problems such as lithium deposition.In the present application, because protrusions and recesses are formed on the positive electrode plate, the surface of the electrode plate has a certain gap structure by uneven textures. Upon exposure to the pressing force, a voltage is released, so that structures inside the electrode plate can be stabilized. Moreover, spaces formed by the recesses and the protrusions of the electrode plate and the separator can store the electrolyte solution, and thus relatively stable storage spaces for the electrolyte solution are provided. This avoids the problem of an inadequate electrolyte solution at a location with voltage concentration. This is advantageous for proper conduction and transfer of the lithium ions and reduces the occurrence of the problem of lithium deposition. Moreover, the uneven textures formed on the surface of the positive electrode plate increase the specific surface area of the positive electrode plate, the lithium ions have more transfer sites and paths to the inside of the electrode plate, so that the transfer rate of the lithium ions inside the electrode plate is increased. Accumulation of lithium ions on the surface of the electrode plate in quick charging of the battery is avoided, and thus the quick charging performance of the battery is improved. When the protrusions and recesses are formed (for example, by rolling), small cracks may be formed on the surface of the positive electrode plate, which may result in a structure of an active material in the positive electrode plate being bent and broken, and thus the aging of lithium ions may not be easily performed, so that the battery power is reduced. In addition, it may also easily result in uneven densification of the positive electrode plate, abnormal local transfer rate of lithium ions, and local lithium deposition. By incorporating the carboxylic acid ester and the nitrile compound as solvent components into the electrolyte solution, the electrolyte solution has a low viscosity and a high dielectric constant, so that the conductivity of the electrolyte solution increases, the transfer rate of lithium ions is accelerated, and the large accumulation of lithium ions at the same place after aging is avoided. At the same time, the transfer rate of the lithium ions can also be accelerated by concentration differences, so that the lithium ions are distributed more uniformly in the electrolyte solution and transferred more uniformly in the electrode plate. This effectively alleviates the problem of the possible uneven transfer rate of the local lithium ions in forming the protrusions or the recesses, so that the surface of the electrode as a whole has a good transfer rate of the lithium ions, reduces local lithium deposition at a embossed portion of the surface of the electrode, and thus improves cycle stability of the battery.In the present application, it is provided that by providing protrusions and recesses on the electrode plate in conjunction with the introduction of the carboxylic acid ester and the nitrile compound as a solvent into the electrolyte solution, the problem of lithium deposition in charging and discharging the multiplied power battery can be solved and the lithium deposition on the surface of the electrode can be reduced. Thereby, problems such as lowering of the capacity of the battery by the lithium deposition of the battery, expansion of the volume of the battery, and the like are reduced, and thus cycle stability for quick charging of the battery is improved.In some embodiments, it is intended that the height (H) of the first bump and the diameter (R) of the first bump be 0.2≤H / R≤80. When H / R>80, a bump structure (also referred to as an embossed structure) of the positive electrode plate is weak, and the embossed structure is liable to be broken by stress. On the one hand, a structure made of an active material within the electrode plate can thereby be damaged and deformed, as a result of which the proper storage or removal of the lithium ions is influenced. On the other hand, an SEI film on the surface of the electrode plate may also deform with the surface structure of the electrode plate during the battery cycles and thus be damaged, so that the battery power is reduced and might cause a safety problem. When H / R<0.2, the emboss is relatively flat and the embossed texture formed is not significant, there is no significant difference between an embossed site and an unembossed site, so that the problems such as structural instability of the electrode plate by stress crush and insufficient electrolyte solution cannot be effectively solved. In addition, the specific surface area of the electrode plate is not significantly increased by the emboss, so that the transfer rate of lithium ions between the electrolyte solution and the electrode plate is not increased, and thus the emboss is not operable. When H and R are preferably 0.75≤H / R≤20, the mechanical strength of the protrusions and the recesses can be equalized, so that the rapid charging performance and the safety of the battery can be further improved.As shown in FIG. 1, in some embodiments, it is provided that the entire surface of the positive electrode plate is embossed. In the thickness direction of the positive electrode plate, the positive electrode plate includes a second surface 3 and a first surface 4 that are disposed opposite to each other. After embossing the second surface 3, the positive electrode plate is formed with a plurality of first depressions 5 evenly spaced apart from each other, while the first surface 4 is formed with a plurality of first protrusions 6 corresponding to the first depressions 5 evenly spaced apart from each other. It is also possible that after embossing the first surface 4 a plurality of first depressions 5 are formed which are distributed uniformly spaced apart from one another, while the second surface 3 is provided with a plurality of first elevations 6 which correspond to the first depressions 5 and are distributed uniformly spaced apart from one another. That is, the positions for forming the first protrusions 6 and the first recesses 5 in the second surface 3 and the first surface 4 may be reversed. The first elevations or the first depressions can be distributed spaced apart from one another either uniformly or non-uniformly, preferably uniformly.In some further embodiments, it is possible that only local areas of the positive electrode plate are embossed, such as at an edge area, a rounded area, etc.In some embodiments, it is provided that the first elevations or the first depressions (i.e. embossed patterns) have regular or irregular shapes, such as, for example, a circular shape, a quadrangular shape, a hexagonal shape, another regular or irregular shape, preferably a regular shape, such as, for example, preferably a circular shape.In some embodiments, it is provided that the arrangement of the first elevations and the first depressions can either be effected uniformly spaced apart from one another or can be adapted according to actual requirements, for example partially uniformly and partially non-uniformly spaced apart from one another.In some embodiments, it is contemplated that the first protrusions and / or the first recesses satisfy at least one of the following conditions: (a) An average distance between adjacent first protrusions or between adjacent first recesses is denoted by D. The average distance between adjacent first protrusions (i.e., both adjacent first protrusions) is 0.5 mm to 8 mm. For example, it may be 0.5 mm, 1 mm, 1.5 mm, 2 mm, 2.5 mm, 3 mm, 3.5 mm, 4 mm, 4.5 mm, 5 mm, 5.5 mm, 6 mm, 6.5 mm, 7 mm, 7.5 mm, 8 mm or any point value in a range formed by any two of the above points, preferably 1 mm to 4 mm; and / or the average distance between adjacent first recesses (i.e., both adjacent first recesses) is 0.5 mm to 8 mm. For example, it may be 0.5 mm, 1 mm, 1.5 mm, 2 mm, 2.5 mm, 3 mm, 3.5 mm, 4 mm, 4.5 mm, 5 mm, 5.5 mm, 6 mm, 6.5 mm, 7 mm, 7.5 mm, 8 mm, or any score in a range formed by any two of the above scores, preferably 1 mm to 4 mm. The average distance between adjacent first protrusions and the average distance between adjacent first recesses may be either the same or different, preferably the same. "The average distance between adjacent first protrusions" and "the average distance between adjacent first recesses" may be understood as a shortest even distance between centers of two closest adjacent first protrusions or two closest adjacent first recesses in the surface of the positive electrode plate in the longitudinal direction of the positive electrode plate. They are referred to as the average distance between adjacent first elevations and the average distance between adjacent first depressions, as represented by D in FIG. 1.When the average distance between first protrusions and / or the average distance between first recesses reaches the above range, the arrangement density of the first protrusions and / or the first recesses is in an appropriate range. By controlling the number of the first protrusions and / or the first recesses in a certain range, not only the improvement in the rapid charging performance of the battery can be effectively ensured, but also it can be avoided that an excessively small average distance leads to the problem such as structural instability of the positive electrode plate.(b) The height of the first protrusion is denoted by H. The height of the first protrusion may be 3 μm, 5 μm, 8 μm, 10 μm, 20 μm, 30 μm, 40 μm, 50 μm, 60 μm, 70 μm, 80 μm, 90 μm, 100 μm, or any dot value in a range formed by any two of the above dots; and / or the depth of the first recess may be 3 μm to 100 μm. For example, it may be 3 μm, 5 μm, 8 μm, 10 μm, 20 μm, 30 μm, 40 μm, 50 μm, 60 μm, 70 μm, 80 μm, 90 μm, 100 μm, or any point value in a range formed by any two of the above point values. "The height of the first protrusion" may be understood as the maximum distance from a positive electrode current collector facing end of the first protrusion to a first surface of the positive electrode plate. "The depth of the first recess" may be understood as the maximum distance from a positive electrode current collector facing bottom end of the first recess to a second surface of the positive electrode plate, as illustrated by H in FIG. 1. When the height of the first protrusion and / or the depth of the first recess reach the above range, too large a height of the first protrusion or too large a depth of the first recess can be avoided, resulting in a weak structure of the protrusion and being prone to breakage of the structure by mechanical crushing and wear. Too small a height of the first protrusion or too small a depth of the first recess may also be avoided, whereby the electrolyte solution may not wet the inside of the positive electrode plate very well, so that the improvement of the rapid charging performance of the battery is not significant.(c) The diameter of the first land is denoted by R. The diameter of the first protrusion is 0.5 mm to 4 mm. For example, it may be 0.5 mm, 1 mm, 1.5 mm, 2 mm, 2.5 mm, 3 mm, 3.5 mm, 4 mm or any point value in a range formed by any two of the above points, preferably 1 mm to 3 mm; and / or the diameter of the first protrusion is 0.5 mm to 4 mm. For example, it may be 0.5 mm, 1 mm, 1.5 mm, 2 mm, 2.5 mm, 3 mm, 3.5 mm, 4 mm, or any score in a range formed by any two of the above scores, preferably 1 mm to 3 mm. "The diameter of the first bump" or "the diameter of the first recess" may be understood as the maximum straight distance between both edges of the first bump or the first recess in a direction parallel to the positive electrode plate, as represented by R in FIG. 1. When the diameter of the first boss and / or the first recess reaches the above range, the size of the area of the first boss and / or the first recess can be controlled to prevent a too large diameter from leading to weakening of the strength of the positive electrode plate, physical structural damage easily occurs, and thereby the structure of the surface of the positive electrode plate is broken, and the battery performance is deteriorated. Moreover, it can also be prevented that the diameter is too small, the electrolyte solution cannot wet the inside of the positive electrode plate very well, and thus the improvement of the rapid charging performance of the battery is not significant.In some embodiments, it is contemplated that the carboxylic acid ester comprises at least one of C4-C10carboxylic acid esters and fluorinated derivatives thereof. It is preferably provided that the carboxylic acid ester comprises at least one of ethyl acetate, propyl acetate, butyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate, ethyl butyrate, propyl butyrate, ethyl difluoroacetate.In some embodiments, it is contemplated that the nitrile compound comprises at least one of C2-C10mononitrile compounds or fluorinated derivatives thereof and C2-C10polynitrile compounds and fluorinated derivatives thereof. Preferably, the nitrile compound comprises at least one of acetonitrile, propionitrile, butyronitrile, isobutyronitrile, malononitrile, succinonitrile, glutaronitrile, adiponitrile, 1,3,6-hexanetricarbonitrile, benzonitrile, acrylonitrile, crotononitrile, trans-butenedinitrile, trans-hexenedinitrile, 1,2-bis(cyanoethoxy)ethane and fluorinated derivatives thereof.The C4-C10carboxylic acid ester has a low viscosity and a relatively high dielectric constant (viscosity≤1 mPa·s; dielectric constant≥10). The C2-C10nitrilic compounds have an average viscosity and a relatively high dielectric constant (viscosity ≤ 2 mPa·s; dielectric constant ≥ 20). In selecting the above carboxylic ester and nitrile compound as a solvent for the electrolytic solution, it is possible to maintain the electrolytic solution at a low viscosity, and to further increase the conductivity of the electrolytic solution, maintain better kinetics, and increase the transfer rate of lithium ions in the electrolytic solution. When wetting the electrode plate, the problem of locally differing the transfer rate of lithium ions in the electrode plate can be reduced more effectively to more evenly transfer the lithium ions, reduce local lithium deposition of the battery, and further improve the rapid charging performance and cycle safety of the battery.In some embodiments, it is contemplated that the carboxylic acid ester comprises propyl propionate (PP) and ethyl difluoroacetate (DFEA); and that the mass ratio of propyl propionate to ethyl difluoroacetate in the electrolyte solution is denoted as C, where C is 1≤C≤10, and where the value of C may be, for example, 1%, 2%, 3%, 4%, 5%, 6%, 8%, 9%, 10% or any point value in a range formed by any two of the above point values. The fluorine atom in the DFEA has a high oxidation potential. When used as a solvent for the electrolyte solution, the antioxidant performance of the electrolyte solution can be significantly improved, so that the electrolyte solution can be stable in the high voltage cycle and the cycle performance of the battery at high voltage is improved. However, DFEA is less soluble for the lithium salt than other carboxylic acid esters. If the level of DFEA is too high, this often results in the deposition of the lithium salt, which may prevent the electrolyte solution from remaining homogeneous, thereby significantly reducing battery power (e.g., cycle power and safety, etc.). In the case of PP as carboxylic esters, carboxy group (-COOH) or ester group (-COO-) can interact strongly with lithium ions in the lithium salt, so that the lithium salt has very good solubility. When PP is used together with DFEA, the solubility of the lithium salt can be improved, the problem such as the lithium salt deposition can be reduced when DFEA is used exclusively, and moreover, the cycle performance of the battery at high voltage can be improved. When PP and DFEA are added to the electrolyte solution and the electrode plate is provided with recesses and protrusions, the uneven textures on the surface of the electrode plate contribute not only to uniform distribution and rapid penetration of the electrolyte solution into the electrode plate, but also optimize the transfer performance of the electrolyte solution and contribute to dissolution and transfer of the lithium salt in the electrolyte solution. To some extent, the risk of lithium salt deposition is mitigated due to a high level of DFEA. At the same time, cycle stability and safety of the battery at high voltage are improved. By using PP together with DFEA and providing the electrode plate with recesses and protrusions, the problem of inhomogeneous electrolyte solution and lithium salt deposition can be solved and, at the same time, cycle performance of the battery at high voltage is improved.In some embodiments, it is contemplated that the fluorinated derivative of the C4-C10carboxylate is fluorinated carboxylic esters; and that the nitrile compound comprises unsaturated nitrile, wherein the unsaturated nitrile comprises at least one of unsaturated mononitrile compounds and fluorinated derivatives thereof, and unsaturated polynitrile compounds and fluorinated derivatives thereof; with respect to the total mass of the electrolyte solution, the total mass proportion of the fluorinated carboxylate and the unsaturated nitrile is denoted as D in %, wherein D is 0≤D≤30, and wherein, for example, it may be 0.1%, 2%, 5%, 8%, 10%, 12%, 14%, 16%, 18%, 20%, 22%, 24%, 26%, 28%, 30%, or any point value in a range formed by any two of the above point values. It is contemplated that the fluorinated carboxylic acid ester comprises at least one of ethyl difluoroacetate, ethyl trifluoroacetate, ethyl 3-fluoropropionate, and ethyl 3,3,3-trifluoropropionate; and / or that the unsaturated nitrile comprises at least one of acrylonitrile, crotononitrile, trans-butenedinitrile, and trans-hexenedinitrile.The fluorine-containing carboxylic acid ester of carboxylic acid esters has strong antioxidant performance due to substitution of fluorine atoms, and can significantly improve antioxidant performance of the entire electrolytic solution and reduce oxidative deterioration of the electrolytic solution. The unsaturated nitrile in the nitrile compound not only has good antioxidant performance, but can also participate in formation of an SEI film on the surface of the electrode plate, so that direct contact between the electrolyte solution and the active material for the electrode is avoided and occurrence of a side reaction is reduced. However, the fluorinated carboxylic acid ester and the unsaturated nitrile usually have high viscosity. If the proportion thereof in the electrolyte solution is too high, this may result in the viscosity of the entire electrolyte solution being significantly increased and thus the conductivity of the electrolyte solution being reduced. As a result, the lithium ions in the electrolyte solution cannot be properly transferred, leading to the occurrence of the problem of lithium deposition on the surface of the electrode, and thus to the reduction of battery power. By providing protrusions and recesses on the surface of the electrode plate and thereby forming uneven textures on the surface of the electrode plate, it is possible to provide more penetration channels for the electrolyte solution, optimize the transfer performance of the electrolyte solution, to some extent alleviate the problem of increasing the viscosity and reducing the conductivity of the electrolyte solution due to high content of the fluorinated carboxylic ester and the unsaturated nitrile. Moreover, this contributes to the guidance of the lithium ions so that they are uniformly distributed and transferred on the surface of the electrode plate and the risk of lithium deposition is reduced. Therefore, the improvement in cycle performance of the battery at high voltage and the rapid charging performance of the battery can be compensated for by adjusting the total mass proportion of the fluorinated carboxylic ester and the unsaturated nitrile to achieve the above range and further providing protrusions and recesses on the surface of the electrode plate.In some embodiments, it is provided that the electrolyte solution comprises a fluorobenzene compound, wherein, with respect to the total mass of the electrolyte solution, the mass fraction of the fluorobenzene compound is denoted as E in %, and wherein the following applies to E: 2≤E≤20 and wherein it may be, for example, 2%, 4%, 6%, 8%, 10%, 12%, 14%, 16%, 18%, 20% or any point value in a range formed by any two of the above points. It is preferably provided that the fluorobenzene compound contains at least one of fluorobenzene, 1,2-difluorobenzene, 1,3-difluorobenzene, 1,4-difluorobenzene, 1,2,3-trifluorobenzene, 1,2,4-trifluorobenzene, 1,2,3,4-tetrafluorobenzene, 1,2,3,5-tetrafluorobenzene, 1,2,4,5-tetrafluorobenzene, pentafluorobenzene, perfluorobenzene and fluorinated aromatic compounds of the above-listed fluorobenzene.By providing the protrusions and the recesses on the surface of the electrode plate, although the specific surface area of the electrode plate is improved and the rate of deposition of the lithium ions into or out of the electrode plate is increased, this also results in the density of compaction of the electrode plate being about high and pores between materials being relatively reduced, which is unfavorable for wetting the electrolyte solution and thus limits the further improvement in the rapid charging performance of the battery. The fluorobenzene compound as aromatic fluorinated alkanes has strong aromatic property. Aromatic structures of the fluorobenzene compound can form a π-π stacking interaction together with electrode structures, so that they can more easily enter the electrode plate. When the fluorobenzene compound as one of the solvents is introduced into the electrolyte solution, the wettability of the electrolyte solution for the electrode plate can be significantly increased, the deposition of the lithium ions into or out of the electrode plate is accelerated, and the lithium deposition on the surface of the electrode is reduced, so that the rapid charging performance of the battery is further optimized. However, the fluorobenzene compound has low polarity and low solubility for the lithium salt. Too high a proportion of the same could lead to the deposition of the lithium salt. When the proportion of the fluorobenzene compound according to the present application is adjusted to achieve the above range, the problem of deposition of the lithium salt due to too high a proportion of the fluorobenzene compound can be avoided, and thus it is ensured that the fluorobenzene compound can function and other battery performances (such as cycle performance and safety, etc.) are not deteriorated.In some embodiments, it is contemplated that the electrolyte solution comprises a lithium salt, wherein, with respect to the total mass of the electrolyte solution, the mass fraction of the lithium salt is 5%-20%, wherein it may be, for example, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 19%, 20%, or any score in a range formed by any two of the above scores, and wherein the lithium salt comprises lithium-containing inorganic salt and / or lithium-containing organic salt.In some embodiments, the lithium-containing inorganic salt is intended to include at least one of LiPF 6, LiB 4 and LiPO 2 F 2.In some embodiments, the lithium-containing organic salt is intended to include at least one of LiBO, LiODFP, LiODFB, LiTFSI, LiFSI, and LiDTI.As a main transfer medium between the positive electrode and the negative electrode of the lithium battery, lithium ions have a direct dependence on the battery powers in terms of their proportion. Particularly in a battery system for which rapid charging and discharging is required, by adjusting the content of the lithium salt to achieve the above range, it is possible to prevent the viscosity of the electrolyte solution from being increased, the transfer of the lithium ions in the electrolyte solution from being influenced, and even the problem of lithium deposition from occurring when the content of the lithium salt is too high. It is also avoided that if the lithium salt is too low, the rapid charging power and the energy density of the battery are reduced and the cycle life of the battery is influenced.Note that in the present application, the mass proportion of the carboxylic ester (A), the mass proportion of the nitrile compound (B), the mass proportion of the propyl propionate, the mass proportion of the ethyl difluoroacetate, the mass proportion of the fluorinated carboxylic ester, the mass proportion of the unsaturated nitrile, and the mass proportion of the fluorobenzene compound (E) can be obtained by gas chromatography-mass spectrometry (GCMS).In some embodiments, it is contemplated that the electrolyte solution comprises a carbonate solvent. The carbonate solvent includes one or more of ethylene carbonate (EC), methylethyl carbonate (EMC), dimethyl carbonate (DMC), diethyl carbonate (DEC), and methylpropyl carbonate (MPC).In some embodiments, it is contemplated that the positive electrode active material layer further comprises a positive electrode active material, a positive conductive agent, and a positive adhesive.In some embodiments, mass percentages of individual components in the positive electrode active material layer are: the positive electrode active material of 90% by weight - 99.2% by weight, the positive conductive agent of 0.4% by weight - 5% by weight, and the positive adhesive of 0.4% by weight - 5% by weight.In some embodiments, it is contemplated that the positive electrode active material is selected from one or more of transition metal lithium oxide, lithium iron phosphate, lithium manganese iron phosphate, lithium manganate, and lithium enriched lithium manganate. The chemical formula of the transition metal lithium oxide is Li (1+x) Ni y Co z M (1-y-z) O 2, wherein -0.1 ≤ x ≤ 1, 0 ≤ y ≤ 1, 0 ≤ z ≤ 1, and 0 ≤ y + z ≤ 1. Here, M refers to one or more of Mg, Zn, Ga, Ba, Al, Fe, Cr, Sn, V, Mn, Sc, Ti, Nb, Mo, and Zr. The positive conductive agent is not particularly limited. It may be, for example, a common positive conductive agent in the art and includes, but is not limited to, acetylene black, conductive carbon black, ketjenblack, conductive graphite, carbon nanotubes, conductive carbon fiber, and graphene. The positive adhesive is not particularly limited. It may be, for example, a conventional adhesive in the art and includes, but is not limited to, one or more of polyvinylidene fluoride, polytetrafluoroethylene, sodium carboxymethylcellulose, styrene-butadiene rubber, and polyethylene oxide.In some embodiments, the negative electrode plate is provided with a negative electrode current collector and a negative electrode active material layer coated on one or both sides of the negative electrode current collector. The negative electrode active material layer includes a negative electrode active material, a negative conductive agent, and a negative adhesive.In some embodiments, mass percentages of individual components in the negative electrode active material layer are: the negative electrode active material of 90% by weight - 99.2% by weight, the negative conductive agent of 0.3% by weight - 5% by weight, and the negative adhesive of 0.5% by weight - 5% by weight.In some embodiments, the negative electrode active material is provided to include one of artificial graphite, natural graphite, hard carbon, soft carbon, silicon carbon, silicon oxygen, nano-silicon and silicon alloy, or a composite of a plurality thereof. The types of the negative conductive agent or the negative adhesive are also not specifically limited. It may be a conventional conductive agent or adhesive in the art. The types of the negative conductive agent include, but are not limited to, at least one of conductive carbon black, acetylene black, ketjenblack, conductive graphite, conductive carbon fiber, carbon nanotubes, and metal powder. The negative adhesive includes, for example, but is not limited to, at least one of styrene-butadiene rubber emulsion, polytetrafluoroethylene emulsion, sodium carboxymethylcellulose, sodium alginate, polyvinyl alcohol, polyacrylic acid, lithium polyacrylate, sodium polyacrylate, and carboxylated chitosan.In the present application, the types of the separator are not particularly limited. It may be, for example, a common separator for the lithium ion battery in the art, and includes, but is not limited to, woven separator, non-woven separator (nonwoven fabric), fine pore separator, bonded separator, separator paper, rolled separator, fine pore separator of polyethylene, and fine pore separator of polypropylene.The technical solutions according to the application are described clearly and completely below with reference to the exemplary embodiments according to the application. Of course, the described exemplary embodiment does not represent all, but a part of the exemplary embodiments according to the application. All other embodiments obtained by persons skilled in the art from the embodiments of the application without inventive activity also belong to the scope of protection of the application.The materials and agents, etc. used in the following embodiments are all commercially available unless otherwise specified.The present application is described in more detail below in conjunction with detailed exemplary embodiments, which are not used to limit the present application but rather to understand it.Example 1-11. Production of a positive electrode plateLithium cobaltate, a conductive agent (mixture of conductive carbon black and carbon nanotubes), and PVDF were added in NMP at a mass ratio of 97.60:1.35:1.05 and stirred uniformly to prepare a positive electrode slurry. The positive electrode slurry was coated uniformly on a front and back surface of an aluminum foil of 9 μm, and the coating density was 0.01704 g / cm 2. By drying and then rolling (with a roll density of 4.2 g / cm 2) a positive electrode plate having a positive electrode active material layer with a one-sided thickness of 90 μm was produced. The positive electrode plate was cut and processed by a special roll having protrusions to form protrusions, the heights of the protrusions being 20 μm, the diameters being 2 mm, and the average distances of the protrusions being 3 mm.2. Production of a negative electrode plateSilicon-containing artificial graphite, conductive carbon black, styrene-butadiene rubber, and sodium carboxymethylcellulose were added in a mass ratio of 97.2:0.5:1.3:1 in deionized water, the proportion of silicon in the silicon-containing artificial graphite being 10%. The above slurry was stirred uniformly to prepare a slurry for negative electrode. The negative electrode slurry was uniformly coated on a negative electrode current collector, dried, rolled and cut. The cut negative electrode plate was processed by a special roll having protrusions to form protrusions, the heights of the protrusions being 20 μm, the diameters being 2 mm, and the average distances of the protrusions being 3 mm.3. Preparation of an Electrolyte SolutionIn an argon-filled glove compartment (humidity <1 ppm, oxygen <1 ppm), ethylene carbonate (EC), diethyl carbonate (DEC) and propyl propionate (PP) were mixed to form a homogeneous solvent. To this, LiPF 6 at a mass ratio of 14% and fluoroacetonitrile at a mass ratio of 15% with respect to the total mass of an electrolyte solution were then slowly added, uniformly stirred to obtain the desired electrolyte solution for a lithium ion battery. With respect to the total mass of the electrolyte solution, the mass ratio of PP was 45%. The total amount of EC and DEC can be calculated and the mass ratio of the two was 1:1.4. Production of a Lithium Ion BatteryThe cut positive electrode plate, separator, and negative electrode were sequentially stacked and then wound into a cell having a wound structure. After the treatments such as packaging, liquid filling, formation and secondary packaging, etc. of the cell, a lithium ion battery was prepared. The separator used here was a substrate 9 μm thick + aluminium oxide ceramic + PVDF adhesive separator.Performance Tests(1) Cycle performance test at 25° CThe batteries manufactured according to an example and a comparative example were cyclically charged and discharged 500 times at 25° C. by a factor of 1 C. in a charge and discharge end voltage range (3.0 V to 4.5 V), the discharge capacity in the first cycle being denoted by x1 mAh and the thickness of the test battery being denoted by y1. The discharge capacity in the 500th cycle was denoted as x2mAh, and the thickness of the battery after the 500th cycle was denoted as y2. The cyclic retention rate for the capacity in the 500th cycle is R1=x2 / x1. The thickness extension of the battery in the 500th cycle is H1 = (y2-y1) / y1.(2) Cycle performance test at 45°CThe batteries manufactured according to an example and a comparative example were cyclically charged and discharged 500 times at 45° C. by a factor of 1 C. in a charge and discharge end voltage range (3.0 V to 4.5 V), the discharge capacity in the first cycle being denoted by x3 mAh and the thickness of the test battery being denoted by y3. The discharge capacity in the 500th cycle was denoted by x4 mAh, and the thickness of the battery after the 500th cycle was denoted by y4. The cyclic retention rate for the capacity in the 500th cycle is R2=x4 / x3. The thickness extension of the battery in the 500th cycle is H2=(y4-y3) / y3.(3) Cycle performance test at 25° C. at 4.7 VThe batteries manufactured according to an example and a comparative example were cyclically charged and discharged 300 times at 25° C. by a factor of 1 C. in a charge and discharge end voltage range (3.0 V to 4.7 V), the discharge capacity in the first cycle being denoted by x1 mAh and the thickness of the test battery being denoted by y1. The discharge capacity in the 300th cycle was denoted as x2mAh, and the thickness of the battery after the 300th cycle was denoted as y2. The cyclic retention rate for the 300th cycle capacity is R = x2 / x1. The thickness extension of the battery in the 300th cycle is H=(y2-y1) / y1.(4) Lithium Deposition TestThe batteries manufactured according to an example and a comparative example were charged at 25° C. to 4.5 V with a constant current of 3 C. and with a constant voltage, and the final current is 0.05 C. Then, they were discharged to 3.0 V with a constant current of 0.5 C. After this was done 20 times, the battery was fully charged. Then, the batteries were disassembled and the lithium deposits were observed, whereby the degree of lithium deposition was divided into no lithium deposition, easy lithium deposition, lithium deposition and strong lithium deposition in order from slightly too difficult.The examples of Groups 1 to 3 and Comparative Examples 1 to 5 are carried out with reference to Example 1-1, and the main differences are shown in Table 1. Here, the examples of Group 1 refer to the change in the height (H) of the first protrusion and / or the change in the diameter (R) of the first protrusion and the change in the ratio of H / R. The examples of Group 2 refer to the change in the mass proportion of the carboxylic ester (A) in the electrolyte solution. The Group 3 examples relate to the change of the mass proportion of the nitrile compound (B) in the electrolytic solution. The ratio of H / R in Comparative Example 1 is too small and does not fall within the scope of the present application. The ratio of H / R in Comparative Example 2 is too large and does not fall within the scope of the present application. The mass proportion of the carboxylic acid ester in the electrolytic solution in Comparative Example 3 is too small and does not fall within the scope of the present application. The mass proportion of the nitrile compound in the electrolytic solution in Comparative Example 4 is too large and does not fall within the scope of the present application. Comparative Example 5 relates to a non-embossed electrode plate. Table 1 Table 1Example 1-120210451587, 91%7,90%82,22%12,49%No lithium depositionExample 1-2400,580**81,72%13,78%76,23%18, 84%Slight lithium depositionExample 1-3340,75**82,25%13,07%77,29%17,60%Slight lithium depositionExamples 1-420120**83,23%11,07%78, 02%16,47%No lithium depositionExamples 1-53,521,75**85,01%9,69%80,76%14,25%No lithium depositionExamples 1-685249**84,02%9,25%79,49%14,28%No lithium depositionExamples 1-7200,366,6 7**82,05%11,55%77,10%17,28%Slight lithium depositionExamples 1-82054**82,00%12,22%77,17%17,04%Slight lithium depositionExamples 1-9221**81,48%11,93%76,95%17,58%Slight lithium depositionExample 2-1***10, 5015, 0082,61%12,05%77,00%17,23%Slight lithium depositionExample 2-2***79, 5015, 0082,41%12,86%77,85%17,53%Slight lithium depositionExample 3-1***45, 003,5 082,17%12,45%77,55%17,65%Slight lithium depositionExample 3-2***45, 0029, 5082,70%12,37%77,58%17,07%Slight lithium depositionExample 10,540, 13**77, 88%17, 08%72,80%22,96%Strong Lithium SeparationExample 2600,5120**77,61%17,37%72,55%22,76%Strong Lithium SeparationExample 3***91577,60%17,54%72,59%22,96%Strong Lithium SeparationComparison Example 4***453577,50%17,88%72,73%22,41%Strong Lithium SeparationExample 5 / / / **75,89%19,12%70,45%24,70%Strong Lithium SeparationNote that "*" means that a corresponding parameter is the same as in Example 1-1 in the example or the comparative example. " / " means that a corresponding parameter has not been tested.The larger the ratio of H / R, the more sharp the emboss of the electrode plate is, so that deformation of the electrode plate when charging and discharging the battery more easily leads to damage and breakage of the structure of the electrode plate. The smaller the ratio of H / R, the flatter the emboss of the electrode plate, so that the emboss is relatively flat and the advantage and effect of the emboss cannot be realized. If the content of the carboxylic acid ester in the electrolytic solution is too high, the antioxidant performance of the electrolytic solution can be reduced. If the proportion of the nitrile compound is too high, the negative electrode of the battery has poor interfacial stability. When the proportion of the carboxylic ester and the nitrile compound is too low, the conductivity of the electrolyte solution cannot be increased and the viscosity of the electrolyte solution cannot be reduced, so that the battery power is reduced. As is apparent from Table 1, by setting according to the present application, the case where H and R are 0.2≤H / R≤80; A is 10≤A≤80; and B is 3≤B≤30. Thereby, the lithium deposition can be reduced, the rapid charging performance of the battery can be improved, and the cycle stability of the battery can be increased.The Group 4 examples are made with reference to Example 1-1, and the major differences are shown in Table 2. The Group 4 examples relate to modified types of carboxylic esters. Table 2 Table 2Example 1-1Propyl propionate87,91%7,90%82,22%12,49%No lithium addition was depositedExample 4-1Ethyl acetate was used86, 61%7,56%80,80%12,97%No lithium addition was depositedExample 4-2Methyl Propionate86, 87%7,71%80,83%12,47%No lithium addition was depositedExample 4-3Propyl butyl tyrate86,67%8,16%81,17%12,71%No lithium addition was depositedAs is apparent from Table 2, analogous effects can be realized by selecting different kinds of carboxylic acid esters in the present application, which can improve the rapid charging performance of the battery, increase the cycle stability of the battery, and reduce the lithium deposition.The Group 5 examples are made with reference to Example 1-1 and the major differences are shown in Table 3. The Group 5 examples relate to modified types of nitrile compounds. Table 3 Table 3Example 1-1Fluoroacetonitrile87,91%7,90%82,22%12,49%No lithium removalExample 5-1Benzonite II85,89%8,27%80,79%12,60%No lithium removalExample 5-2Hexanedini tril86,79%7,28%80,29%12,26%No lithium removalExample 5-31,2-Bis(cyanoethoxy)et han85,68%7,47%80,13%12,52%No lithium removalAs can be seen from Table 3, analogous effects can be realized by the selection of different nitrile compounds that can improve the rapid charging performance of the battery, increase the cycle stability of the battery, and reduce the lithium deposition.The Group 6 examples are made with reference to Example 1-1, and the major differences are shown in Table 4. In this case, the examples from group 6 relate to the elevations being processed by a specific roller having different parameters and with elevations, such that the average distances of the first elevations are changed. Table 4 Table 4Example 6-10,882,10%12,07%77,24%17,97%Slight lithium depositionExample 6-27,982,97%12,02%77,51%17,30%Slight lithium depositionExamples 6-30,377,95%17,96%72,43%22,98%Strong Lithium SeparationExamples 6-4977,47%17,93%72,53%22,01%Strong Lithium SeparationAs can be seen from Table 4, when the battery is charged and discharged, the electrode plate easily deforms, and this easily causes damage and breakage of the structure of the electrode plate, and thus reduction of the battery power, if the average distances are too small. If the average distances are too large, the density of the emboss on the surface of the electrode plate is too small, so that the emboss is not fully functional after it is formed. When the average distances of the first protrusions and the average distances of the first recesses reach the range of 0.5 mm to 8 mm, the rapid charging performance of the battery can be improved, the cycle stability of the battery can be increased, and the lithium deposition can be reduced.The Group 7 examples are made with reference to Example 1-1, and the major differences are shown in Table 5. Here, the Group 7 examples refer to that ethyl difluoroacetate (DFEA) was further added to the electrolyte solution and the mass ratio C of propyl propionate (PP) to ethyl difluoroacetate (DFEA) was changed. Table 5 Table 5C. CCyclic Reduction Rate at 25° CThickness dimension at 25° CCycle Retention at 45°CThickness dimension at 45°CLithhi umabs cheidungCycle Retention at 25 °C (4.7 V)Thick at 25 °C (4.7 V)Example 1-1 / 87,91 %7,90%82,22%12,49%No lithia umab79,27%15,2 8%Example 7-1589,15 %5,35%84,43%10,85%No lithia umab82,63 %12,7 0%Example 7-2188,33 %6,91%83,08%11,66%Similar lithia umabs chloride formation80,85%14,9 3%Example 7-31088,59 %6,71%83,09%11,97%Similar lithia umabs chloride formation81,88%13,5 6%Example 7-40,584,13 %10,70%79,54%15,18%Lithhi umabs cheidung76,49%18,7 2%Example 7-51184,43 %10,14%79,33%15,76%Lithhi umabs cheidung77,64%17,1 0%References: " / " means that a corresponding parameter has not been tested.As is apparent from Table 5, the value of the mass ratio C of PP to DFEA is too large. This means that the mass proportion of DFEA in the electrolyte solution is too small, so that the antioxidant performance of the electrolyte solution and the battery performance are inferior. At the same time, the value of C is too small, the viscosity of the electrolyte solution is too high, and the solubility of the lithium salt is too low, so that a strong lithium deposition occurs and the battery power is reduced. When C 1≤C≤10, the cycle power of the battery at high voltage can be further increased, and also the rapid charging power of the battery is taken into account.The Group 8 examples are made with reference to Example 7-1 and the major differences are shown in Table 6. Here, the Group 8 examples refer to that, for the kinds of nitrile compounds in the electrolytic solution proper, the fluoroacetonitrile was replaced with the trans-hexenedinitrile, and the total mass proportion D in % was changed from the fluorinated carboxylic ester (DFEA) and the unsaturated nitrile (trans-hexenedinitrile). Table 6 Table 6Example 8-11589,34%5,46%84,09%10,00%No lithium removalExample 8-23088,22%6,68%83,33%11,07%Slight removal of lithiumExample 8-33584,77%10,91%79,13%15,26%Lithium ReductionAs is apparent from Table 6, when the nitrile compound in the electrolytic solution refers to an unsaturated nitrile (trans-hexenedinitrile), the antioxidant performance of the electrolytic solution can be further enhanced by the cooperation with the fluorinated carboxylic acid ester (DFEA). In conjunction with the embossing of the electrode plate, the rapid charging power of the battery can be taken into account at the same time when the cycle power of the battery is further improved at high voltage. However, if too much unsaturated nitrile and fluorinated carboxylic acid ester were added to the electrolyte solution, this could lead to too high viscosity of the electrolyte solution and deterioration of battery performance.The Group 9 examples are made with reference to Example 8-1, and the major differences are shown in Table 7. Here, the Group 9 Examples refer to further adding a fluorobenzene (fluorobenzene compound) to the electrolytic solution and adjusting the mass ratio E in % of fluorobenzene in the electrolytic solution. Table 7 Table 7Example 9-17,589,99%5,38%84,35%10,34%No lithium removalExample 9-29,888,54%6,14%83,88%11,64%Slight removal of lithiumExamples 9-32,388, 946,57%83, 45%11,16%Slight removal of lithiumExamples 9-41284,05%10,43%79,75%15,94%Lithium ReductionAs is apparent from Table 7, a fluorobenzene compound was further added to the electrolyte solution. When E 2≤E≤10, the lithium deposition on the surface of the electrode can be further reduced, the rapid charging performance of the battery can be optimized, and the cycle stability of the battery can be improved. E is prevented from being too large, so that the solubility of the lithium salt deteriorates and the battery performance is reduced.It should be understood that the terms "comprise," "include," or any variants thereof should cover a non-exclusive inclusion, such that processes, methods, products, or devices comprising a series of elements further include other elements, not explicitly listed, or elements inherent in these processes, methods, products, or devices, besides such elements. Without further limitation, an element limited by the term "comprising a... " does not exclude the presence of additional identical elements in a process, method, product, or apparatus having said element. Moreover, it should be noted that, within the scope of the methods and apparatuses in embodiments of the present application, they are not limited to implementing their functions in the sequence shown or discussed, but they may also implement their functions substantially simultaneously or in the reverse sequence according to the functions involved. For example, the described methods may be performed in an order other than the described order, and various steps may be added, omitted, or combined with each other. In addition, features described with reference to some examples may be combined in a further example.Above, only the preferred embodiments of the present application have been explained, but the application is not intended to be limited thereto. All modifications, equivalent substitutions, etc., which fall within the scope of the spirit and principle of the application are intended to be included within the scope of the application.

Claims

A lithium ion battery, characterized in that the battery comprises a positive electrode plate, a negative electrode plate and an electrolyte solution, wherein the positive electrode plate comprises, in its thickness direction, a first surface and a second surface arranged opposite to each other, wherein the first surface is provided with a plurality of first protrusions arranged spaced apart from each other, and the second surface is provided with a plurality of first recesses, respectively, wherein the height of the first protrusion is denoted by H in μm and the diameter of the first protrusion is denoted by R in mm, and wherein H and R are 0.2 ≤ H / R ≤ 80; wherein the electrolyte solution comprises a carboxylic acid ester whose mass proportion with respect to the total mass of the electrolyte solution is denoted by A in %, and wherein A is denoted by 10 ≤ A ≤ 80; wherein the electrolyte solution comprises a nitrile compound whose mass fraction with respect to the total mass of the electrolyte solution is denoted as B in %, and wherein the following applies to B: 3≤B≤30.The battery according to claim 1, characterized in that for H and R, 0.75 ≤ H / R ≤ 20; and / or that the carboxylic acid ester comprises at least one of C4-C10 carboxylic acid esters and fluorinated derivatives thereof; and / or that the nitrile compound comprises at least one of C2-C10 mononitrile compounds and fluorinated derivatives thereof and C2-C10 polynitrile compounds and fluorinated derivatives thereof.The battery of claim 2, characterized in that the carboxylic acid ester comprises at least one of ethyl acetate, propyl acetate, butyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate, ethyl butyrate, propyl butyrate, ethyl difluoroacetate; and / or that the nitrile compound comprises at least one of acetonitrile, propionitrile, butyronitrile, isobutyronitrile, malononitrile, succinonitrile, glutaronitrile, adiponitrile, 1,3,6-hexanetricarbonitrile, benzonitrile, acrylonitrile, crotononitrile, trans-butenedinitrile, trans-hexenedinitrile, 1,2-bis(cyanoethoxy)ethane, and fluorinated derivatives thereof.The battery of claim 3, characterized in that the carboxylic acid ester comprises propyl propionate and ethyl difluoroacetate; and that the mass ratio of propyl propionate to ethyl difluoroacetate in the electrolyte solution is denoted as C, where C is: 1 ≤ C ≤ 10.The battery of claim 2, characterized in that the fluorinated derivative of the C4-C10 carboxylic ester is fluorinated carboxylic esters; and / or that the nitrile compound comprises unsaturated nitrile, wherein the unsaturated nitrile comprises unsaturated mononitrile compound and fluorinated derivatives thereof and unsaturated polynitrile compound and fluorinated derivatives thereof.The battery according to claim 5, characterized in that, with respect to the total mass of the electrolyte solution, the total mass fraction of the fluorinated carboxylic ester and the unsaturated nitrile is denoted by D in %, where D is: 0 ≤ D ≤ 30; and / or that the fluorinated carboxylic ester comprises at least one of ethyl difluoroacetate, ethyl trifluoroacetate, ethyl 3-fluoropropionate and ethyl 3,3,3-trifluoropropionate; and / or that the unsaturated nitrile comprises at least one of acrylonitrile, crotonnitrile, trans-butenedinitrile and trans-hexenedinitrile.Battery according to any of claims 1 to 6, characterized in that the first protrusions and / or the first recesses meet at least one of the following conditions: (a) an average distance between the adjacent first protrusions of 0.5 mm - 8 mm, and / or an average distance between the adjacent first recesses of 0.5 mm - 8 mm; (b) a height of the first protrusion of 3 μm - 100 μm, and / or a depth of the first recess of 3 μm - 100 μm; and (c) a diameter of the first protrusion of 0.5 mm - 4 mm, and / or a diameter of the first recess of 0.5 mm - 4 mm.Battery according to claim 7, characterized in that the first protrusions and / or the first recesses meet at least one of the following conditions: (a) an average distance between the adjacent first protrusions of 1 mm - 4 mm, and / or an average distance between the adjacent first recesses of 1 mm - 4 mm; (b) a height of the first protrusion of 5 μm - 80 μm, and / or a depth of the first recess of 5 μm - 80 μm; and (c) a diameter of the first protrusion of 1 mm - 3 mm, and / or a diameter of the first recess of 1 mm - 3 mm.Battery according to any one of claims 1 to 6, characterised in that the electrolyte solution comprises a fluorobenzene compound, the proportion by mass of the fluorobenzene compound being denoted by E in % with respect to the total mass of the electrolyte solution, and E being as follows: 2 ≤ E ≤ 20.The battery according to claim 9, characterized in that the fluorobenzene compound includes at least one of fluorobenzene, 1,2-difluorobenzene, 1,3-difluorobenzene, 1,4-difluorobenzene, 1,2,3-trifluorobenzene, 1,2,4-trifluorobenzene, 1,2,3,4-tetrafluorobenzene, 1,2,3,5-tetrafluorobenzene, 1,2,4,5-tetrafluorobenzene, pentafluorobenzene, perfluorobenzene, and fluorinated aromatic compounds of fluorobenzene.The battery according to any one of claims 1 to 6, characterized in that the electrolyte solution comprises a lithium salt, wherein the mass proportion of the lithium salt is 5% - 20% with respect to the total mass of the electrolyte solution, and wherein the lithium salt comprises lithium-containing inorganic salt and / or lithium-containing organic salt.The battery of claim 11, characterized in that the lithium-containing inorganic salt comprises at least one of LiPF 6, LiB 4 and LiPO 2 F 2 and / or that the lithium-containing organic salt comprises at least one of LiBO, LiODFP, LiODFB, LiTFSI, LiFSI and LiDTI.

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