Negative electrode plate, secondary battery and electrical device
Patent Information
- Application Number
- DE202024106827
- Authority / Receiving Office
- DE · DE
- Patent Type
- Utility models
- Current Assignee / Owner
- Priority Date
- 2023-06-14
- Filing Date
- 2024-06-03
- Publication Date
- 2025-03-27
- Estimated Expiration
- 2034-06-30
Abstract
Description
TECHNICAL FIELD
[0001] The present disclosure relates to the technical field of batteries, in particular to a negative electrode plate or negative pole piece, a secondary battery and an electrical or electronic device. BACKGROUND
[0002] In recent years, with the continuous development and popularization of electric vehicles, the requirements for the performance of electric vehicle batteries have become increasingly stringent, and in particular, the current continuous mileage is receiving increasing attention. The battery is the core component of electric vehicles, and battery energy density is one of the key factors affecting the continuous mileage of electric vehicles, so improving battery energy density is very important.
[0003] As described in the prior art, the energy density of the battery can be increased by increasing the compacted density of the electrode plates. However, increasing the compacted density of the electrode plates also leads to other problems, such as a decrease in the liquid absorption capacity (wettability) of the electrode plates at low temperatures, which also reduces the battery life.
[0004] Therefore, it would be desirable to provide an electrode plate that has both a high compacted density and good wettability. SUMMARY
[0005] An object of the present disclosure is to overcome the disadvantages of the prior art and to provide a negative electrode plate, a secondary battery, and an electrical device, wherein the negative electrode plate has a higher compacted density, maintains good low-temperature wettability, and has good liquid absorption capacity for an electrolyte solution at a low temperature, and a battery comprising the negative electrode plate has an excellent cycle life. The invention is defined by the features of the independent claims. Advantageous embodiments are subject to the dependent claims.
[0006] To achieve the above-mentioned object, in a first aspect of the present disclosure, the present disclosure provides a negative electrode plate comprising a negative electrode current collector and an anode active material layer provided on at least one surface of the negative electrode current collector, wherein the negative electrode active material layer comprises an anode active material, wherein the negative electrode active material comprises graphite, and the negative electrode plate satisfies the following relationship: a=In(DFW)+10×In(Dv50)+1 / 3(La)+26.5, b=PD,a / 45−b≥0.05, where D FW is a full width at half maximum or half-value width of a particle size volume distribution of the negative electrode active material with the unit µm, D v50 is a particle diameter corresponding to 50% of a cumulative volume distribution percentage of the negative electrode active material with the unit µm, La is the average size of a crystal in the a-axis direction measured by Raman spectroscopy on the negative electrode plate with the unit nm, and PD is a compaction or compacted density of the negative electrode plate with the unit g / cm 3 is.
[0007] In a preferred embodiment of the present disclosure, the negative electrode plate satisfies the following relationship: 0.06≤a / 45-b≤0.15.
[0008] In a preferred embodiment of the present disclosure, D FW in a range of 10 µm to 35 µm.
[0009] In a further preferred embodiment of the present disclosure, D FW in a range of 15 µm to 30 µm.
[0010] In a preferred embodiment of the present disclosure, D v 50 in a range of 5 µm to 20 µm.
[0011] In a further preferred embodiment of the present disclosure, D v 50 in a range of 8 µm to 15 µm.
[0012] In a preferred embodiment of the present disclosure, the La value is in a range of 50 nm to 80 nm.
[0013] In a further preferred embodiment of the present disclosure, the La value is in a range of 65 nm to 75 nm.
[0014] In a preferred embodiment of the present disclosure, PD is in a range of 1.3 g / cm 3 up to 1.8 g / cm 3 .
[0015] In a further preferred embodiment of the present disclosure, PD is in a range of 1.60 g / cm 3 up to 1.75 g / cm 3 .
[0016] In a preferred embodiment of the present disclosure, the negative electrode plate further satisfies the following relationship: 9.5≤5.5×b−In(c)≤11.5, where c is an ion transport impedance of the negative electrode plate with the unit ohm (Ω).
[0017] In a preferred embodiment of the present disclosure, c is in the range of 0.05Ω to 2 Ω.
[0018] In a second aspect of the present disclosure, the present disclosure provides a secondary battery comprising a positive electrode plate or a positive pole piece, a negative electrode plate, and an electrolyte solution, wherein the negative electrode plate is the negative electrode plate described above.
[0019] In a third aspect of the present disclosure, the present disclosure provides an electrical device including the secondary battery described above.
[0020] Advantageous effects of the present disclosure are as follows: The present disclosure has developed a negative electrode plate, a secondary battery including the same, and an electrical device. By appropriately controlling a particle diameter distribution of the negative electrode active material in the negative electrode plate, as well as the crystal size and compacted density of the negative electrode plate, the negative electrode plate of the present disclosure maintains good low-temperature wettability at a higher compacted density and has good liquid absorption capacity for an electrolyte solution at a low temperature, and a battery including the negative electrode plate has an excellent cycle life. DETAILED DESCRIPTION
[0021] To clarify the purpose, technical solutions, and advantages of the embodiments of the present disclosure, the technical solutions in the embodiments of the present disclosure are described clearly and completely below. Of course, the described embodiments are only a part of the embodiments of the present disclosure, not all of them. Starting from the embodiments of the present disclosure, all other embodiments obtained by a person skilled in the art without inventive effort fall within the scope of the present disclosure.
[0022] In the present disclosure, a closed technical solution consisting of the mentioned features also includes an open technical solution including the mentioned features, wherein the technical features are described in an open manner.
[0023] Throughout this disclosure, reference is made to numerical ranges, which, unless otherwise noted, are to be considered continuous and include both the minimum and maximum values of the range, as well as any value between the minimum and maximum values. When a range refers to an integer, it also includes any integer between the minimum and maximum values of the range. When multiple ranges are specified to describe a feature or characteristic, the ranges may also be combined. In other words, unless otherwise noted, all ranges disclosed herein include all subranges contained therein.
[0024] In the present disclosure, the specific dispersion and stirring treatment methods are not particularly limited.
[0025] The reagents or instruments used in this disclosure are, unless the manufacturer is specified, commercially available products. Negative electrode plate
[0026] One embodiment of the present disclosure provides a negative electrode plate comprising a negative electrode current collector and a negative electrode active material layer provided on at least one surface of the negative electrode current collector, wherein the negative electrode active material layer comprises a negative electrode active material, the negative electrode active material comprising graphite, and the negative electrode plate satisfies the following relationship: a=In(DFW)+10×In(Dv50)+1 / 3(La)+26.5,b=PD,a / 45−b≥0.05; where D FW is a half-width of the particle size volume distribution of the negative electrode active material with the unit µm, D v50 is a particle diameter corresponding to 50% of a cumulative volume distribution percentage of the negative electrode active material with the unit µm, La is an average size of a crystal in the a-axis direction measured by Raman spectroscopy on the negative electrode plate with the unit nm and PD is the compressed density of the negative electrode plate with the unit g / cm 3 is.
[0027] D FW and D v 50 represents the particle diameter distribution of the negative electrode active material in the negative electrode plate, and La represents the average size of a crystal in the a-axis direction (referred to as the transverse crystal size) on a microscopic scale of the negative electrode plate. In the present disclosure, a=ln(D FW )+10×ln(D V 50)+1 / 3(La)+26.5, ie the size of the value of a depends on the combination of D FW , D V50 and La, so that the morphology features of the negative electrode plate can be combined at both the macro and micro levels. When a / 45-b≥0.05, the morphology characteristics and compacted density of the negative electrode plate are within a suitable range, which not only promotes the penetration of lithium ions into a graphite layer through defects and can lead to unhindered intercalation and deintercalation of lithium ions, but also promotes the wetting of the electrolyte solution and the negative electrode active material. A thickness of the SEI film formed by the reaction is controlled within a specific range, so that the negative electrode plate has excellent liquid absorption capacity for the electrolyte solution at a low temperature and good wettability, and the battery containing the negative electrode plate has a long cycle life.
[0028] In one of the embodiments, the negative electrode plate satisfies the following relationship: 0.06≤a / 45-b≤0.15,
[0029] In one of the preferred embodiments, the negative electrode plate satisfies the following relationship: 0.08≤a / 45−b≤0.12.
[0030] The larger the a / 45-b ratio, the better the low-temperature wettability of the negative electrode plate. However, the a / 45-b value should not be too high, as this may lead to a reduction in the battery's energy density or affect the battery's charge / discharge rate.
[0031] In the present disclosure, D FWThe half-width of a particle size volume distribution of the negative electrode active material, i.e., the difference between the two particle diameter values, which corresponds to half the maximum height of an interval particle diameter distribution curve of the negative electrode active material. The interval particle diameter distribution curve (also called the differential particle diameter distribution) of the negative electrode active material is well-known in the art and is defined as a curve plotted with the particle diameter as the abscissa and a volume percentage as the ordinate, which can more accurately represent the particle diameter distribution characteristics of the negative electrode active material particles.
[0032] D V 50 is a particle diameter corresponding to 50% of a cumulative volume distribution percentage of the negative electrode active material. Regarding the method for detecting DFW and D V 50, the present disclosure is not limited and a person skilled in the art would have been able to FW and D V 50 of the negative electrode active material by conventional technical means, and as an example, a laser particle size analyzer, such as a Master Sizer 3000 laser particle size analyzer from Malvern Panalytical Ltd. (UK), could be used.
[0033] To control the particle diameter of the negative electrode active material (including the regulation of D FW and D v50) A classification sieve method is generally used, and the specific classification sieve method is not particularly limited and can be selected according to actual circumstances. Sieve sorting is generally used. The negative electrode active material is thrown into sieves with different mesh sizes for sieving. Since the particle diameters of the particles are different, the particles with a small particle diameter are sieved out by the sieves, and the desired particle diameters can be retained on the sieves, so that negative electrode active material with different particle diameters can be obtained. Active substances with special particle diameter dimensions can be formulated according to needs, so their particle diameter distribution can be manually adjusted.
[0034] In one of the embodiments, the D FWin a range from 10 µm to 35 µm and is, for example, 12 µm, 15 µm, 18 µm, 20 µm, 25 µm, 30 µm or 33 µm.
[0035] In one of the preferred embodiments, the D FW in a range of 15 µm to 30 µm.
[0036] In one of the embodiments, D V 50 in a range from 5 µm to 20 µm and is, for example, 7 µm, 8 µm, 10 µm, 11 µm, 13 µm, 15 µm or 18 µm.
[0037] In one of the preferred embodiments, D V 50 in a range of 8 µm to 15 µm.
[0038] If the D FWis within the above-mentioned preferred range of the present disclosure, the negative electrode active material has a relatively wide range of particle diameter distribution, and large-size particles and small-size particles are mixed, so that an increase in the compacted density of the negative electrode plate is achieved without reducing the low-temperature wettability of the negative electrode plate. If the D V 50 value of the negative electrode active material is larger, the negative electrode plate can achieve a higher compacted density, which contributes to improving the electrochemical performance of the battery. The D V However, the 50 value should not be so large that it leads to uneven distribution of the negative electrode active material layer or reduces the battery life.
[0039] In the present disclosure, the La value of the negative electrode plate is measured by Raman spectroscopy and calculated by the following formula: La=2.4×10 -10 ×λ 4 ×(A D / A G ) -1 , where λ is the wavelength of the incident light in the Raman spectrum, A D the area of a D-peak (located in a waveband range of 1320 cm -1 up to 1380 cm -1 ) in the Raman spectrum and A G the area of a G-peak (located in a waveband range of 1560 cm -1 up to 1600 cm -1 ) in the Raman spectrum.
[0040] The La of the negative electrode plate is the La in a state where the negative electrode active material is contained in the anode active layer / coating or negative electrode active material layer of the negative electrode plate. As is known, the negative electrode active material layer is prepared by mixing raw materials including the negative electrode active material, a binder, and a conductive material with a solvent to prepare a slurry, applying the slurry to a current collector, and then drying and rolling the current collector. The La of the negative electrode active material changes during the preparation process, so it is necessary to clearly distinguish the physical properties of the negative electrode active material in the raw material state and the negative electrode active material in the negative electrode active material layer state.The two cannot be considered equivalent. Once the negative electrode active material is uniformly distributed and solidified on the negative electrode plate, its crystallite size is essentially stable during battery use. However, in order to regularly control the initial grain defects of the negative active material, the negative active material may be graphite that has undergone thermal processing. In particular, the graphite material is subjected to thermal processing under inert conditions, that is, in an atmosphere essentially free of oxygen, including but not limited to an atmosphere containing an inert gas (e.g., nitrogen, argon, etc.).After thermal processing under inert conditions, the amount of defects, dislocations, or discontinuities in the graphite grains can be reduced, thereby adjusting the regularity of the graphite crystals. Conventional conditions can be used for thermal treatment of the graphite material.
[0041] The above-mentioned thermal treatment of graphite is not an essential step in the present disclosure, and the technical problem of the present disclosure can also be solved if the negative electrode active material satisfying the above-mentioned relationship range can be obtained in the negative electrode active material layer by mass sieving and after specifically controlling the preparation conditions.
[0042] In one embodiment, La is in a range of 50 nm to 80 nm, e.g., 55 nm, 59 nm, 65 nm, 67 nm, 69 nm, 72 nm, 75 nm, or 79 nm.
[0043] In one of the preferred embodiments, the La value is in a range of 65 nm to 75 nm.
[0044] If the La value of the negative electrode plate is too small, the crystallinity of the negative electrode active material is relatively low and the capacity is small, which limits the improvement of the energy density of the lithium-ion battery; if the La value of the negative electrode plate is too large, the diffusion distance after the lithium ions are intercalated into the negative electrode active material layer becomes longer, resulting in an increase in diffusion resistance and easy lithium precipitation during high-rate charging and discharging, thereby reducing the cycle life of the battery.
[0045] In one of the embodiments, PD is in the range of 1.3 g / cm 3 up to 1.8 g / cm 3 , and is, for example, 1.35 g / cm 3 , 1.4 g / cm 3 , 1.45 g / cm 3 , 1.5 g / cm 3, 1.6 g / cm 3 , 1.65 g / cm 3 , 1.7 g / cm 3 or 1.75g / cm 3 .
[0046] In one of the preferred embodiments, PD is in a range of 1.60 g / cm 3 up to 1.75 g / cm 3 .
[0047] The compressed density of the negative electrode plate indicates the degree of compaction between the substances in the negative electrode active material layer. Generally, the compressed density is related to the energy density of the material, and if the compressed density is too low, the energy density of the battery will be low. Therefore, in this patent, it is preferred that the PD of the negative electrode plate be not less than 1.3 g / cm 3 Furthermore, the inventors found that the negative electrode plate has both a high compacted density and excellent wetting performance at low temperatures when PD is in a range of 1.60 g / cm 3up to 1.75 g / cm 3 lies.
[0048] In one of the embodiments, the negative electrode plate further satisfies the relationship: 9.5≤5.5×bIn(c)≤11.5, where c is an ion transport impedance (R ion ) of the negative electrode plate with the unit Ohm (Ω).
[0049] The ion transport impedance R ionThe negative electrode plate can be measured as follows: A symmetrical battery with two identical negative electrode plates is prepared. Electrochemical impedance spectroscopy (EIS) of the symmetrical battery is performed using an electrochemical workstation, and the alternating current impedance spectra are obtained by the EIS test. Impedance analysis is performed by combining an equivalent circuit and an impedance decomposition model, and the Nyquist diagram and Bode diagram are obtained. Z-View or EC-Lab software is used for fitting, and the degree of agreement between a simulation diagram and a measured diagram is improved by adjusting the values of the various impedances. To R ion To obtain the value, the calculation is carried out according to the following formula: Z' ω→0 =R sol -R ion / 3, where R sol an ohmic impedance and Z' ω→0is a mixed impedance; the values of R sol and Z' ω→0 can be obtained according to the Nyquist diagram of EIS (see the detection method in this document: Ogihara N, Kawauchi S, Okuda C, et al. Theoretical and experimental analysis of porous electrodes for lithium-ion batteries by electrochemical impedance spectroscopy using a symmetric cell[J]. Journal of The Electrochemical Society, 2012, 159(7): A1034.).
[0050] When the ion transport impedance and compacted density of the negative electrode plate are 9.5≤5.5×bIn(c)≤11.5, the ion transport impedance and compacted density are within a reasonable range, and the battery has good electrochemical performance and excellent wetting performance at low temperatures.
[0051] In one of the designs, c is in a range from 0.05Ω to 2Ω and is, for example, 0.1Ω, 0.15Ω, 0.2Ω, 0.3Ω, 0.4Ω, 0.5Ω, 0.6Ω, 0.8Ω, 1.0Ω, 1.5Ω or 1.8Ω.
[0052] In one of the preferred embodiments, c is in the range of 0.1Ω to 1.0Ω.
[0053] The ion transport impedance reflects the transport rate of electrolyte ions in the electrode channels. Generally, at a low ion transport impedance, the transport rate of electrolyte ions is relatively high, which contributes to the electrolyte solution's better wetting of the electrode plate at low temperatures. The ion transport impedance of the negative electrode plate is affected by various factors, such as the porosity, the pore structure of the negative electrode active material layer, the morphology of the negative electrode active material, and so on. Although the wetting performance of the negative electrode plate is better when the ion transport impedance is lower, the performance of the negative electrode plate may be unstable due to a lower ion transport impedance, resulting in a reduction in the battery's cycle life.
[0054] The graphite in the negative electrode active material according to the present disclosure may include natural graphite and / or artificial graphite.
[0055] The method for preparing the negative electrode active material is not particularly limited in the present disclosure, and a person skilled in the art can prepare the negative electrode active material by conventional means.
[0056] For example, the method for preparing the negative electrode active material can be as follows: Crushing and granulating a graphite raw material to obtain a granular product; subjecting the granular product to a graphitization treatment at a temperature of 2500°C to 3500°C for a period of 5 hours to 8 hours, controlling a gradient temperature rise during the graphitization treatment, for example, heating at a rate of 5°C / min to 20°C / min; then performing a carbonization treatment at a temperature of 700°C to 1500°C for a period of 4 hours to 8 hours to obtain artificial graphite; and recovering the negative electrode active material by sieving and sorting; The procedure for preparing the negative electrode active material can also be as follows: Collecting natural graphite ore to obtain natural flake graphite by crushing, ball milling, and flotation, and performing isostatic pressing after screening, acid washing treatment, and spheronization treatment, wherein the conditions for the isostatic pressing are: a temperature of 100°C to 300°C and a pressure of 70 MPa to 85 MPa, and a time of 30 minutes to 180 minutes; after mixing the obtained product with a coating material, performing a carbonization treatment at a temperature of 700°C to 1300°C for a time of 5 hours to 7 hours; and obtaining the negative electrode active material by screening and sorting; in it, the coating material can also be a high-purity asphalt, and the mixing mass ratio between the isostatically pressed product and the coating material is (97-99):(1-3).
[0057] As for the negative electrode plate, the present disclosure does not particularly limit the negative electrode current collector as long as it has high conductivity without causing adverse chemical changes in the battery, and for example, copper, stainless steel, aluminum, nickel, titanium, burnt carbon, copper or stainless steel surface-treated with any of the elements carbon, nickel, titanium, silver, or the like, or an aluminum-cadmium alloy can be used.
[0058] The negative electrode active material layer of the negative electrode plate may comprise, in addition to the negative electrode active material, a conductive agent and a binder.
[0059] The conductive agent serves to improve the electrical conductivity of the negative electrode active material layer, and the present disclosure does not impose any particular restrictions on the conductive agent. For example, carbon powder such as carbon black, acetylene black, Ketjen black, channel black, furnace black, lamp black, or thermal black; graphite powder such as natural graphite or artificial graphite; conductive fibers such as carbon fibers or metal fibers; and conductive whiskers such as zinc oxide whiskers or potassium titanate whiskers may be used.
[0060] The binder serves to improve the adhesion between the conductive agent, the negative electrode active material, and the negative electrode current collector. The binder is not particularly limited in the present disclosure, and, for example, a polymer material such as a fluororesin-based binder, a rubber-based binder, a cellulose-based binder, a polyol-based binder, a polyolefin-based binder, a polyimide-based binder, a polyester-based binder, a silane-based binder, or the like can be used.
[0061] Furthermore, the negative electrode active material layer may comprise a thickener, in which case carboxymethyl cellulose may be used.
[0062] It should be noted that the method for preparing the negative electrode plate is not particularly limited in the present disclosure, and that a person skilled in the art would have been able to manufacture the negative electrode plate by conventional methods.
[0063] For example, the procedure for preparing the negative electrode plate can be as follows: Coating a negative electrode slurry, which can be prepared by dissolving or dispersing the negative electrode active material and optionally the binder and the conductive agent in the solvent, with the negative electrode current collector, followed by rolling or drying; or Carrying out the preparation by pouring the negative electrode slurry onto a separate support and then laminating a membrane separated from the support onto the negative electrode current collector. secondary battery
[0064] One embodiment of the present disclosure provides a secondary battery comprising a positive electrode plate, a negative electrode plate, and an electrolyte or electrolyte solution, wherein the negative electrode plate is the negative electrode plate described above.
[0065] The positive electrode plate of the present disclosure includes a positive electrode current collector and a cathode active material layer provided on at least one surface of the positive electrode current collector, wherein the positive electrode active material layer includes a cathode active material and may further include a conductive agent and / or a binder.
[0066] The present disclosure does not particularly limit the positive electrode current collector as long as it has high conductivity without causing adverse chemical changes in the battery. For example, copper, stainless steel, aluminum, nickel, titanium, copper or stainless steel surface-treated with carbon, nickel, titanium, silver, or the like, or an aluminum-cadmium alloy may be used. The positive electrode current collector may be the same as or different from the negative electrode current collector of the present disclosure.
[0067] The positive electrode active material is a compound that can reversibly intercalate and deintercalate with lithium, and for example, the positive electrode active material may comprise a lithium composite metal oxide containing lithium and at least one metal selected from the group consisting of nickel (Ni), cobalt (Co), manganese (Mn), iron (Fe), and aluminum (Al). In particular, the positive electrode active material may comprise at least one of the following: Li(Ni) 0,6 Mn 0,2 Co 0,2 )O2, Li(Ni 0,7 Mn 0,2 Co 0,10 )O2, Li(Ni 0,8 Mn 0‚1 Co 0,1 )O2, Li(Ni 0,8 Co 0,15 A1 0,05 )O2, Li(Ni0, 86 Mn 0,07 Co 0,05 Al 0,02 )O2, Li(Ni 0,9 Mn 0,05 Co 0,05 )O2.
[0068] The conductive agent serves to improve the electrical conductivity of the positive electrode active material layer, and the present disclosure does not specifically limit the conductive agent. The conductive agent in the positive electrode plate may be the same as or different from the conductive agent in the negative electrode plate of the present disclosure.
[0069] The binder serves to improve the adhesion between the conductive agent, the positive electrode active material, and the positive electrode current collector, and the binder is not particularly limited in the present disclosure. The binder in the positive electrode plate may be the same as or different from the binder in the negative electrode plate of the present disclosure.
[0070] It should be noted that the method for preparing the positive electrode plate is not particularly limited in the present disclosure, and that a person skilled in the art would have been able to manufacture the positive electrode plate by conventional methods.
[0071] The procedure for preparing the positive electrode plate can be as follows: Coating a positive electrode slurry, which can be prepared by dissolving or dispersing the positive electrode active material and optionally the binder and the conductive agent in the solvent, with the positive electrode current collector, followed by rolling or drying; or Perform the preparation by pouring the positive electrode slurry onto a separate support and then laminating a membrane separated from the support onto the positive electrode current collector.
[0072] The electrolyte or electrolytic solution of the present disclosure may be any electrolytic solution suitable for use in electrochemical energy storage devices according to the prior art. The electrolytic solution comprises an electrolyte and a solvent, and the electrolyte may generally comprise a lithium salt, and more particularly, the lithium salt may be an inorganic lithium salt and / or an organic lithium salt. The solvent in the electrolytic solution is generally a non-aqueous solvent, and more particularly, the solvent comprises at least one of ethylene carbonate, propylene carbonate, butylene carbonate, pentylene carbonate, dimethyl carbonate, diethyl carbonate, dipropyl carbonate, ethyl methyl carbonate / methyl ethyl carbonate, or a halogenated derivative thereof.
[0073] The secondary battery may further include a separator disposed between the positive electrode plate and the negative electrode plate to separate the positive electrode plate and the negative electrode plate from each other and prevent the positive electrode plate and the negative electrode plate from contacting and causing a short circuit. The separator may be any of a variety of known materials suitable for use as a spacer separator for electrochemical energy storage devices. In particular, the separator comprises at least one of the following materials: polyethylene, polypropylene, polyvinylidene fluoride, aramid, polyethylene terephthalate, polytetrafluoroethylene, polyacrylonitrile, polyimide, polyamide, polyester, and natural fiber. Electrical device
[0074] One embodiment of the present disclosure provides an electrical device including the secondary battery described above. The secondary battery serves as a power supply for the electrical device.
[0075] An electrical device refers to any device that can harness electrical energy and convert it into one or more forms of energy, such as mechanical energy, heat energy, light energy, etc., e.g., an electric motor, an electric heat engine, an electric light source, etc. This may specifically include electrical devices, electric vehicles, electric trains, ships and satellites, energy storage systems, etc. Electrical devices may include mobile phones, laptops / notebooks, drones / unmanned aerial vehicles, sweeping robots, electric cigarettes, etc.; electric vehicles may include pure electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, electric bicycles, electric scooters, electric golf carts, electric trucks, etc.
[0076] The disclosure is further explained in connection with the following specific examples. In certain embodiments of the present disclosure, the method for determining D v 50 and D FW of the negative electrode active material as follows: Carrying out measurements using a laser particle size testing method with a Malvern particle size tester according to the following steps: Dispersing the negative electrode active material to be tested in deionized water in which a dispersant (such as nonylphenol polyoxyethylene ether with a content of 0.03 wt%) is dispersed to form a mixture, the mixture is sonicated for 2 minutes and then placed in a particle size tester for testing; Obtaining D FWfrom a difference between the two particle diameter values, which corresponds to half the maximum height of the interval particle diameter distribution curve of the active material, and obtaining the D V 50 from the particle diameter, which corresponds to 50% of the cumulative volume distribution percentage of the negative electrode active material.
[0077] In particular embodiments of the present disclosure, the method for detecting La of the negative electrode plate is as follows: Obtain the La of the negative electrode plate by test analysis with the Thermo Fisher Raman spectrometer, and calculate the La according to the following formula: La=2.4×10 -10 ×λ 4 ×(A D / A G ) -1 , where λ is the wavelength of the incident light of the Raman spectrum, A D the area of the D-peak (located in a waveband of 1320 cm -1 to 1380cm -1 ) in the Raman spectrum and A Gthe area of the G-peak (located in a waveband of 1560 cm -1 to 1600cm -1 ) in the Raman spectrum; and the Raman spectroscopy analysis conditions are as follows: Using a laser light with a wavelength of 785 nm and a beam spot of less than 1 µm 2 at room temperature and under normal atmospheric pressure
[0078] In certain embodiments of the present disclosure, the method for detecting the PD of the negative electrode plate is performed as follows: Density of the negative electrode plate PD=m / V, where in the formula, m is the mass of the negative electrode active material layer with the unit g and m can be weighed with an electronic balance with an accuracy of 0.01 g or more; V is the volume of the negative electrode active material layer with the unit cm 3, where the volume V is the product of the area Ar of the negative electrode active material layer and the thickness of the negative electrode active material layer, and the thickness can be measured with a spiral micrometer with an accuracy of 0.5 µm.
[0079] In certain embodiments of the present disclosure, the method for detecting R ion the negative electrode plate as follows: Preparation of a symmetrical battery using two identical negative electrode plates, measuring the AC impedance of the symmetrical battery using an electrochemical workstation and recording electrochemical impedance spectroscopy (EIS) of the symmetrical battery, where the specific test conditions are as follows: sinusoidal AC voltage excitation with an amplitude of 5 mV and a frequency range of 0.1 Hz to 10 6Hz; Obtaining the Nyquist diagram and the Bode diagram based on the equivalent circuit and the impedance decomposition model and then fitting them by Z-View or EC-Lab software, then improving the degree of agreement between the simulated diagram and the measured diagram by adjusting the values of the different impedances to obtain the ion transport impedance R ion of ions in the electrode plate. In certain embodiments of the present disclosure, the method for determining a contact angle is as follows: with ethylene carbonate and methyl ethyl carbonate (weight ratio 1:1) as solvent, determining the contact angle of the negative electrode plate using a contact angle tester JC2000 D2M manufactured by Shanghai Zhongchen Digital Technology Equipment Co. Ltd. (powereach), the specific determination conditions being as follows: keeping the negative electrode plate in an environment of -10°C for 30 minutes, then drop by drop the solvent at different positions on the surface of the negative electrode plate (one drop at each position), using a contact angle tester to observe the moment when the drop completely contacts the electrode plate, calculating the contact angle at this moment, and obtaining an average value according to the test results at different positions, namely the contact angle of the negative electrode plate.
[0080] In particular embodiments of the present disclosure, the method for determining a compacted state is as follows: Observe the surface of the negative electrode plate after rolling treatment, where: if there is no abnormality on the surface after rolling, it is a good surface; if there are one or more streaks or blasting spots with a darker color within 5 cm of an edge of the negative electrode plate and there is no abnormality in other areas, it is edge overprint; and if there are one or more streaks or blasting spots with a darker color in a central area in addition to the edge of the negative electrode plate, it is serious overprint.
[0081] In certain embodiments of the present disclosure, the method for determining cycle life is as follows: Using a battery charge / discharge tester to conduct a charge / discharge cycle test on the lithium-ion battery at 25°C, the charge / discharge system operating as follows: charging the battery with 1 C constant current to 4.25 V, then charging the battery with constant voltage until the current drops to 0.02 C, and after 5 minutes of standing, discharging the battery with 1 C constant current to 2.5 V, which corresponds to one cycle; as the battery cycles, the battery capacity decreases, and the number of cycles at which the capacity drops to 80% of an initial discharge capacity is recorded as the battery's cycle life. Design 1
[0082] This embodiment is a lithium-ion battery, and the specific preparation procedure is as follows: (1) Preparation of the negative electrode plate: (1.1) A mechanical mill or a roller mill is used to crush the non-acicular raw petroleum coke, and after crushing, sorting is carried out to regulate the particle diameter distribution of the obtained particulate product; after shaping the granular product obtained after crushing, the obtained granular product is placed in a reaction vessel of a granulator, and the graphitization treatment is carried out without adding a binder; the product obtained by granulation is placed in a graphitization furnace, and the graphitization treatment is carried out under the following conditions: the temperature is maintained at 2800 °C for 3 hours and then increased to 3300 °C at 15 °C / min for 3 hours;Then, a carbonization treatment is carried out at a temperature of 1020 °C for 8 hours, and no additional pressure is applied during the carbonization treatment, thereby obtaining artificial graphite; then, the artificial graphite is sieved and sorted through a sorting screen to obtain the negative electrode active material with a D; v 50 of 12 µm and a D FW of 25.1 µm; (1.2) The negative electrode active material, the conductive agent (carbon black), the thickener (carboxymethyl cellulose, CMC), and the binder (styrene-butadiene rubber, SBR) are mixed in a mass ratio of 95:1.5:1.5:2.0. A vacuum stirrer is used to prepare the negative electrode slurry in a wet process. The negative electrode slurry is evenly coated on the negative electrode current collector (copper foil). The negative electrode current collector coated with the negative electrode slurry is placed in an oven for drying. Then, rolling and slitting are performed, and the rolling conditions are controlled to form the negative electrode plate with a PD of 1.68 g / cm 3 to obtain. (2) Preparation of the positive electrode plate the positive electrode active material Li(Ni 0,7 Mn 0,2 Co 0,1)O2, the binder (polyvinylidene fluoride), the positive electrode active material, and the conductive agent (carbon black) are mixed in a mass ratio of 95:2.5:2.5, N-methylpyrrolidone (NMP) is added, and stirring is carried out under the action of a vacuum stirrer until the mixed system forms the positive electrode slurry with uniform fluidity; the positive electrode slurry is evenly coated on the positive electrode current collector (aluminum foil); the positive electrode current collector coated with the positive electrode slurry is transferred to a furnace for drying and then rolled and slitted to obtain the positive electrode plate. (3) Preparation of the electrolyte solution Ethylene carbonate (EC) and ethyl methyl carbonate (EMC) are mixed in a weight ratio of 1:1 to obtain an organic solvent, and then sufficient dried lithium salt LiPF6 is dissolved in the mixed organic solvent to prepare the electrolyte solution with a concentration of 1 mol / L. (4) Preparation of the separator A separator made of polyethylene (PE) coated with ceramic and polyvinylidene fluoride is used. (5) Preparation of the battery The prepared positive electrode plate, separator, and negative electrode plate are wound to obtain a bare cell without liquid injection; the bare cell is packed in an outer packaging film, the above-mentioned prepared electrolyte solution is injected into the dried bare cell, and the lithium-ion battery is obtained by vacuum packaging, standing, forming, molding, sorting, and other processes. Design 2
[0083] Embodiment 2 provides a lithium-ion battery whose preparation is substantially the same as that of Embodiment 1, except that: When preparing the negative electrode plate, the conditions for the graphitization treatment are as follows: the temperature is maintained at 2790 °C for 2 hours, then the temperature is increased to 2900 °C at 10 °C / min and maintained for 4 hours; and for the carbonization treatment, the temperature is 1000 °C and the duration is 6 hours. The artificial graphite is sieved and sorted so that D V 50 and D FW of the negative electrode active material in Table 1; and the rolling conditions are adjusted so that PD of the negative electrode plate corresponds to Table 1. Design 3
[0084] Embodiment 3 provides a lithium-ion battery whose preparation is substantially the same as that of Embodiment 1, except that When preparing the negative electrode plate, the conditions for the graphitization treatment are as follows: the temperature is maintained at 2815 °C for 3 hours, then the temperature is increased to 2950 °C at 13 °C / min and maintained for 3 hours; and for the carbonization treatment, the temperature is 830 °C and the duration is 4.5 hours. The artificial graphite is sieved and sorted so that D V 50 and D FW of the negative electrode active material in Table 1; and the rolling conditions are adjusted so that PD of the negative electrode plate corresponds to Table 1. Design 4
[0085] Embodiment 4 provides a lithium-ion battery whose preparation is substantially the same as that of Embodiment 1, except that: When preparing the negative electrode plate, the conditions for the graphitization treatment are as follows: the temperature is maintained at 3025 °C for 4 hours, then the temperature is increased to 3200 °C at 10 °C / min and maintained for 2 hours; and for the carbonization treatment, the temperature is 850 °C and the duration is 4 hours. The artificial graphite is sieved and sorted so that D V 50 and D FW of the negative electrode active material in Table 1; and the rolling conditions are adjusted so that PD of the negative electrode plate corresponds to Table 1. Design 5
[0086] Embodiment 5 provides a lithium-ion battery whose preparation is substantially the same as that of Embodiment 1, except that: When preparing the negative electrode plate, the conditions for the graphitization treatment are as follows: the temperature is maintained at 3000 °C for 3 hours, then the temperature is increased to 3150 °C at 15 °C / min and maintained for 3.5 hours; and for the carbonization treatment, the temperature is 800 °C and the duration is 7.5 hours. The artificial graphite is sieved and sorted so that D V 50 and D FW of the negative electrode active material in Table 1; and the rolling conditions are adjusted so that PD of the negative electrode plate corresponds to Table 1. Design 6
[0087] Embodiment 6 provides a lithium-ion battery whose preparation is substantially the same as that of Embodiment 1, except that: When preparing the negative electrode plate, the conditions for the graphitization treatment are as follows: the temperature is maintained at 2830 °C for 2.5 hours, then the temperature is increased to 3000 °C at 20 °C / min and maintained for 3.5 hours; and for the carbonization treatment, the temperature is 1000 °C and the time is 7.5 hours. The artificial graphite is sieved and sorted so that D V 50 and D FW of the negative electrode active material in Table 1; and the rolling conditions are adjusted so that PD of the negative electrode plate corresponds to Table 1. Design 7
[0088] Embodiment 7 provides a lithium-ion battery whose preparation is substantially the same as that of Embodiment 1, except that: When preparing the negative electrode plate, the conditions for the graphitization treatment are as follows: the temperature is maintained at 2850 °C for 3.5 hours, then the temperature is increased to 2900 °C at 10 °C / min and maintained for 3 hours; and for the carbonization treatment, the temperature is 1310 °C and the duration is 4 hours. The artificial graphite is sieved and sorted so that D V 50 and D FW of the negative electrode active material in Table 1; and the rolling conditions are adjusted so that PD of the negative electrode plate corresponds to Table 1. Design 8
[0089] Embodiment 8 provides a lithium-ion battery whose method of preparation is substantially the same as that of Embodiment 1, except that: In the preparation of the negative electrode plate, the negative electrode active material is prepared by the following method: natural graphite ore is used to obtain natural flake graphite through a step of crushing, ball milling, and flotation, and after sieving, acid washing, and spheronization, isostatic pressing is carried out, and the conditions for the isostatic pressing are as follows: a temperature of 170 °C, a pressure of 80 MPa, and a time of 60 minutes; the product after isostatic pressing is mixed with high-purity asphalt in a mass ratio of 98:2, and the mixture is subjected to carbonization treatment, wherein the temperature for the carbonization treatment is 780 °C and the time is 6.5 hours; then, sieving and sorting are carried out to D v 50 and D FWto obtain materials corresponding to the negative electrode active material described in Table 1; the rolling conditions are adjusted so that PD of the negative electrode plate corresponds to Table 1. Design 9
[0090] Embodiment 9 provides a lithium-ion battery whose preparation is substantially the same as that of Embodiment 1, except that: When preparing the negative electrode plate, the conditions for the graphitization treatment are as follows: the temperature is maintained at 2610 °C for 3 hours, then the temperature is increased to 2900 °C at 15 °C / min and maintained for 3 hours; and for the carbonization treatment, the temperature is 1350 °C and the duration is 4 hours. The artificial graphite is sieved and sorted so that D V 50 and D FW of the negative electrode active material in Table 1; and the rolling conditions are adjusted so that PD of the negative electrode plate corresponds to Table 1. Design 10
[0091] Embodiment 10 provides a lithium-ion battery whose preparation is substantially the same as that of Embodiment 1, except that: In the preparation of the negative electrode plate, the negative electrode active material is prepared by the following process: natural graphite ore is used to obtain natural flake graphite through a step of crushing, ball milling, and flotation, and after sieving, acid washing, and spheronization, isostatic pressing is carried out. The conditions for the isostatic pressing are as follows: a temperature of 200 °C, a pressure of 75 MPa, and a time of 90 minutes. The product after isostatic pressing is mixed with high-purity asphalt in a mass ratio of 99:1, and the mixture is subjected to carbonization treatment. For the carbonization treatment, the temperature is 1280 °C and the time is 6 hours. Subsequently, sieving and sorting are carried out to obtain D V 50 and D FWto obtain materials corresponding to the negative electrode active material described in Table 1; the rolling conditions are adjusted so that PD of the negative electrode plate corresponds to Table 1. Design 11
[0092] Embodiment 11 provides a lithium-ion battery whose preparation is substantially the same as that of Embodiment 1, except that: When preparing the negative electrode plate, the conditions for the graphitization treatment are as follows: the temperature is maintained at 2600 °C for 4 hours, then the temperature is increased to 2750 °C at 15 °C / min and maintained for 2 hours; and for the carbonization treatment, the temperature is 840 °C and the duration is 4 hours. The artificial graphite is sieved and sorted so that D V 50 and D FW of the negative electrode active material in Table 1; and the rolling conditions are adjusted so that PD of the negative electrode plate corresponds to Table 1. Design 12
[0093] Embodiment 12 provides a lithium-ion battery whose preparation is substantially the same as that of Embodiment 1, except that: When preparing the negative electrode plate, the conditions for the graphitization treatment are as follows: the temperature is maintained at 3000 °C for 3 hours, then the temperature is increased to 3100 °C at 10 °C / min and maintained for 3 hours; and for the carbonization treatment, the temperature is 830 °C and the duration is 8 hours. The artificial graphite is sieved and sorted so that D V 50 and D FW of the negative electrode active material in Table 1; and the rolling conditions are adjusted so that PD of the negative electrode plate corresponds to Table 1. Design 13
[0094] Embodiment 13 provides a lithium-ion battery whose preparation is substantially the same as that of Embodiment 1, except that: When preparing the negative electrode plate, the conditions for the graphitization treatment are as follows: the temperature is maintained at 3200 °C for 3.5 hours, then the temperature is increased to 3280 °C at 8 °C / min and maintained for 2.5 hours; and for the carbonization treatment, the temperature is 1010 °C and the duration is 4 hours. The artificial graphite is sieved and sorted so that D V 50 and D FW of the negative electrode active material in Table 1; and the rolling conditions are adjusted so that PD of the negative electrode plate corresponds to Table 1. Design 14
[0095] Embodiment 14 provides a lithium-ion battery whose preparation is substantially the same as that of Embodiment 1, except that: When preparing the negative electrode plate, the conditions for the graphitization treatment are as follows: the temperature is maintained at 3100 °C for 3 hours, then the temperature is increased to 3260 °C at 8 °C / min and maintained for 3 hours; and for the carbonization treatment, the temperature is 1070 °C and the time is 7.5 hours. The artificial graphite is sieved and sorted so that D V 50 and D FW of the negative electrode active material in Table 1; and the rolling conditions are adjusted so that PD of the negative electrode plate corresponds to Table 1. Design 15
[0096] Embodiment 15 provides a lithium-ion battery whose preparation is substantially the same as that of Embodiment 1, except that: When preparing the negative electrode plate, the conditions for the graphitization treatment are as follows: the temperature is maintained at 3050 °C for 3 hours, then the temperature is increased to 3200 °C at 10 °C / min and maintained for 3 hours; and for the carbonization treatment, the temperature is 1250 °C and the duration is 6 hours. The artificial graphite is sieved and sorted so that D V 50 and D FW of the negative electrode active material in Table 1; and the rolling conditions are adjusted so that the PD of the negative electrode plate corresponds to Table 1. Comparative Example 1
[0097] Comparative Example 1 provides a lithium-ion battery whose preparation is substantially the same as that of Embodiment 1, except that: When preparing the negative electrode plate, the conditions for the graphitization treatment are as follows: the temperature is maintained at 2800 °C for 3 hours, then the temperature is increased to 3000 °C at 10 °C / min and maintained for 4 hours; and for the carbonization treatment, the temperature is 1000 °C and the duration is 4 hours. The artificial graphite is sieved and sorted so that D V 50 and D FW of the negative electrode active material in Table 1; and the rolling conditions are adjusted so that the PD of the negative electrode plate corresponds to Table 1. Comparative Example 2
[0098] Comparative Example 2 provides a lithium-ion battery whose preparation is substantially the same as that of Embodiment 1, except that: When preparing the negative electrode plate, the conditions for the graphitization treatment are as follows: the temperature is maintained at 2600 °C for 3 hours, then the temperature is increased to 2800 °C at 15 °C / min and maintained for 3 hours; and for the carbonization treatment, the temperature is 930 °C and the time is 4.5 hours. The artificial graphite is sieved and sorted so that D V 50 and D FW of the negative electrode active material in Table 1; and the rolling conditions are adjusted so that the PD of the negative electrode plate corresponds to Table 1. Comparative Example 3
[0099] Comparative Example 3 provides a lithium-ion battery whose preparation is substantially the same as that of Embodiment 1, except that: When preparing the negative electrode plate, the conditions for graphitization treatment are as follows: the temperature is maintained at 2640 °C for 2 hours, then the temperature is increased by 15 °C / min to 2760 °C and maintained for 3.5 hours; and for carbonization treatment, the temperature is 1150 °C and the duration is 4 hours. The artificial graphite is sieved and sorted so that D V 50 and D FW of the negative electrode active material in Table 1; and the rolling conditions are adjusted so that PD of the negative electrode plate corresponds to Table 1.
[0100] The D V 50 and D FW -values of the negative electrode active material as well as the La, PD and R ion-values of the negative electrode plate prepared in the embodiments and comparative examples are listed in Table 1. Table 1: D FW (µm) D V 50 (µm) La (nm) PD (g / cm 3 ) a / 45-b R ion (Q) 5.5×b-ln(c) Design 1 25,1 12 70 1,68 0,05 0,438 10,07 Design 17,2 13,4 69,4 1,68 0,06 0,525 9,88 2 Design 3 15,5 14,9 65,1 1,65 0,08 0,623 9,55 Design 4 30 11,5 73 1,65 0,10 0,496 9,78 Design 5 29,5 10,1 74,5 1,61 0,12 0,079 11,39 Design 6 21,6 13,2 70,2 1,6 0,15 0,229 10,27 Design 7 29,8 15 72,3 1,62 0,18 0,529 9,55 Design 8 34,7 8,2 73,7 1,6 0,08 0,244 10,21 Design 9 10,2 19,9 60,2 1,6 0,15 0,375 9,78 Design 10 28,2 16,1 80 1,72 0,15 0,862 9,61 Design 11 33 5,2 51,2 1,33 0,08 0,11 9,52 Design 12 28,5 18,5 74,4 1,8 0,06 0,963 9,94 Design 13 24,3 17,6 78 1,74 0,13 0,052 12,53 Design 14 25 18,2 77,1 1,75 0,13 0,66 10,04 Design 15 25,2 17,8 77,6 1,75 0,13 1,899 8,98 Comparative Example 1 17,5 13,0 68,1 1,7 0,03 1,694 8,82 Comparative Example 2 37 7,8 54,8 1,51 0,02 0,136 10,30 Comparative Example 3 11,2 19,9 58,8 1,71 0,03 0,375 10,39
[0101] The surface states of the negative electrode plates prepared in the embodiments and comparative examples are observed, the contact angles of the negative electrode plates are measured, and the cycle life of the lithium-ion batteries prepared in the embodiments and comparative examples is measured, and the results are shown in Table 2. Table 2: Surface condition Contact angle (°) Cycle life Design 1 good surface 62,7 3765 Design 2 good surface 61,6 3790 Design 3 good surface 60,1 3850 Design 4 good surface 56,3 4015 Design 5 good surface 51,9 4120 Design 6 good surface 50,4 4160 Design 7 good surface 49,9 4195 Design 8 good surface 60,7 3815 Design 9 good surface 50,8 4135 Design 10 good surface 51,5 4120 Design 11 good surface 61,4 3800 Design 12 good surface 62,3 3775 Design 13 good surface 46,9 3980 Design 14 good surface 53,2 4050 Design 15 good surface 57,0 3875 Comparative Example 1 Edge overpressure 71,5 3010 Comparative Example 2 severe overpressure 88,2 2490 Comparative Example 3 Edge overpressure 74,4 2840
[0102] From the combination of the test results in Tables 1 and 2, it can be seen that when the negative electrode plates meet the requirements of a / 45-b ≥ 0.05, they all exhibit a lower wetting angle, indicating that the negative electrode plates maintain good wetting performance at a low temperature and have a higher cycle life; however, when the value of a / 45-b of the negative electrode plate is less than 0.05, the wettability of the material deteriorates, and the cycle life also decreases, and after the negative electrode plates prepared in Comparative Examples 1-3 are subjected to rolling, the surfaces of the negative electrode plates exhibit various degrees of overpressure.
[0103] According to Embodiments 1 to 7, the values of a / 45-b are higher, and the wetting angles of the negative electrode plates tend to decrease, indicating that the wetting performance of the electrode plates is improved. However, the value of a / 45-b should not be too high, which may lead to a reduction in the energy density of the battery (for example, if the value of a / 45-b of the negative electrode plate is 0.2, the energy density of the battery decreases by about 5% compared to Embodiment 1) or the battery's charge / discharge rate is affected.
[0104] According to Embodiments 8-12, the wetting angle and the lifetime of the negative electrode plate deteriorate to a certain extent when D V 50 and D FW of the negative electrode active material or La and PD of the negative electrode plate are in a non-preferred range.
[0105] According to Embodiments 13 to 15, it can be seen that in the case where the values of a / 45-b of the negative electrode plates are close to or equal to each other, the lower the ion transport impedance (c value) is, the better the contact performance of the negative electrode plates, and when the negative electrode plate satisfies a value of 5.5×b-ln(c) of 9.5-11.5, the negative electrode plate has excellent wetting performance and excellent cycle life of the battery is also ensured. QUOTES CONTAINED IN THE DESCRIPTION
[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited non-patent literature
[0000] Ogihara N, Kawauchi S, Okuda C, et al. Theoretical and experimental analysis of porous electrodes for lithium-ion batteries by electrochemical impedance spectroscopy using a symmetric cell[J]. Journal of The Electrochemical Society, 2012, 159(7): A1034
[0049]
Claims
[1] A negative electrode plate comprising a negative electrode current collector and a negative electrode active material layer provided on at least one surface of the negative electrode current collector, wherein the negative electrode active material layer comprises a negative electrode active material, characterized by that the negative electrode active material comprises graphite, and the negative electrode plate satisfies the following relationship: a=In(DFW)+10×In(Dv50)+1 / 3(La)+26.5, b=PD,a / 45−b≥0.05, where D FW is a half-width of a particle size volume distribution of the negative electrode active material in the unit µm, D V 50 is a particle diameter corresponding to 50% of a cumulative volume distribution percentage of the negative electrode active material in the unit µm, La is an average size of a crystal in the a-axis direction measured by Raman spectroscopy on the negative electrode plate in the unit nm, and PD is a compressed density of the negative electrode plate in a unit g / cm 3 . [2] Negative electrode plate according to claim 1, characterized by that the negative electrode plate satisfies the following relationship: 0.06≤a / 45-b≤0.
15. [3] Negative electrode plate according to one of the preceding claims, characterized by that D FW in a range of 10 µm to 35 µm. [4] Negative electrode plate according to one of the preceding claims, characterized by that D FW in a range of 15 µm to 30 µm. [5] Negative electrode plate according to one of the preceding claims, characterized by that D V 50 is in a range of 5 µm to 20 µm. [6] Negative electrode plate according to one of the preceding claims, characterized bythat D V 50 is in a range of 10 µm to 15 µm. [7] Negative electrode plate according to one of the preceding claims, characterized by that the La is in a range of 50 nm to 80 nm. [8] Negative electrode plate according to one of the preceding claims, characterized by that the La lies in a range of 65 nm to 75 nm. [9] Negative electrode plate according to one of the preceding claims, characterized by that PD is in a range of 1.3 g / cm 3 up to 1.8 g / cm 3 . [10] Negative electrode plate according to one of the preceding claims, characterized by that PD is in a range of 1.60 g / cm 3 up to 1.75 g / cm 3 lies. [11] Negative electrode plate according to one of the preceding claims, characterized by that the negative electrode plate also satisfies the following relationship: 9.5≤5.5×b−In(c)≤11.5, where c is an ion transport impedance of the negative electrode plate in units of ohms (Ω). [12] Negative electrode plate according to claim 11, characterized by that the c lies in a range from 0.05 Ω to 2 Ω. [13] Negative electrode plate according to claim 11 or 12, characterized by that the c lies in a range from 0.1 Ω to 1.0 Ω. [14] Negative electrode plate according to one of the preceding claims, wherein copper, stainless steel, aluminum, nickel, titanium, burnt carbon or an aluminum-cadmium alloy is provided or used for the negative electrode current collector. [15] The negative electrode plate according to any one of the preceding claims, wherein the negative electrode active material layer comprises, in addition to the negative electrode active material, a conductive agent and a binder. [16] The negative electrode plate according to claim 15, wherein the conductive agent comprises carbon powder, graphite powder, conductive fibers, or conductive whiskers. [17] The negative electrode plate according to claim 15 or 16, wherein the binder comprises a polymer material. [18] A negative electrode plate according to any one of the preceding claims, wherein the negative electrode active material layer comprises a thickener, e.g. carboxymethylcellulose. [19] Secondary battery, in particular lithium-ion battery, comprising a positive electrode plate, a negative electrode plate and an electrolyte solution or electrolyte, characterized by that the negative electrode plate is the negative electrode plate according to one of claims 1 to 18. [20] The secondary battery according to claim 19, wherein the positive electrode plate comprises a positive electrode current collector and a positive electrode active material layer provided on at least one surface of the positive electrode current collector, wherein the positive electrode active material layer comprises a positive electrode active material [21] A secondary battery according to claim 20, wherein copper, stainless steel, aluminum, nickel, titanium, burnt carbon or an aluminum-cadmium alloy is provided or used for the positive electrode current collector. [22] A secondary battery according to claim 20 or 21, wherein the positive electrode current collector is identical to or different from the negative electrode current collector. [23] The secondary battery according to any one of claims 20 to 22, wherein the positive electrode active material comprises a lithium composite metal oxide containing lithium and at least one metal selected from the group consisting of Ni, Co, Mn, Fe and Al. [24] A secondary battery according to any one of claims 20 to 23, wherein the positive electrode active material comprises at least one of the following compounds or materials: Li(Ni 0,8 Mn 0,1 Co 0,1 )O2, Li(Ni 0,8 Co 0,15 Al 0,05 )O2 and Li(Ni 0,86 Mn 0,07 Co 0,05 Al 0,02 )O2. [25] A secondary battery according to any one of claims 20 to 24, wherein the positive electrode active material comprises at least one of the following compounds or materials: Li(Ni 0,6 Mn 0,2 Co 0,2 )O2 and Li(Ni 0,7 Mn 0,2 Co 0,10 )O2. [26] A secondary battery according to any one of claims 20 to 25, wherein the positive electrode active material comprises at least the following compound or material Li(Ni 0,9 Mn 0,05 Co 0,05 )O2. [27] A secondary battery according to any one of claims 20 to 26, wherein the positive electrode active material layer comprises a conductive agent. [28] A secondary battery according to claim 27, wherein the conductive means of the positive electrode plate is identical to or different from a conductive means of the negative electrode plate. [29] A secondary battery according to any one of claims 20 to 28, wherein the positive electrode active material layer comprises a binder. [30] A secondary battery according to claim 29, wherein the binder of the positive electrode plate is identical to or different from a binder of the negative electrode plate. [31] A secondary battery according to any one of claims 19 to 30, wherein the electrolytic solution comprises an electrolyte and a solvent. [32] A secondary battery according to any one of claims 19 to 31, wherein the electrolyte comprises a lithium salt. [33] A secondary battery according to claim 32, wherein the lithium salt is an inorganic lithium salt and / or an organic lithium salt. [34] A secondary battery according to any one of claims 31 to 33, wherein the solvent is a non-aqueous solvent, [35] A secondary battery according to any one of claims 31 to 34, wherein the solvent comprises at least one of ethylene carbonate, propylene carbonate, butylene carbonate, pentylene carbonate, dimethyl carbonate, diethyl carbonate, dipropyl carbonate, methyl ethyl carbonate or a halogenated derivative thereof. [36] A secondary battery according to any one of claims 19 to 35, comprising a separator between the positive electrode plate and the negative electrode plate. [37] A secondary battery according to claim 36, wherein the separator comprises at least one of the following materials: polyethylene, polypropylene, polyvinylidene fluoride, aramid, polyethylene terephthalate, polytetrafluoroethylene, polyacrylonitrile, polyimide, polyamide, polyester and natural fiber. [38] A secondary battery according to any one of claims 19 to 37 for use in supplying power to an electrical device, the electrical device comprising: Electric motor, heat engine, light source, vehicle, train, ship, satellite, energy storage system, mobile phone, notebook, unmanned aerial vehicle, sweeping robot, or electronic cigarette. [39] The secondary battery of claim 38, wherein the vehicle is a pure electric vehicle, a hybrid electric vehicle, a plug-in hybrid electric vehicle, an electric bicycle, an electric scooter, an electric golf cart, or an electric truck. [40] Electrical device, characterized bythat it comprises the secondary battery according to one of claims 19 to 39. [41] An electrical device according to claim 40, wherein the secondary battery serves as a power supply for the electrical device. [42] An electrical device according to claim 41, which is configured as an electric motor, heat engine, light source, vehicle, train, ship, satellite, energy storage system, mobile phone, notebook, unmanned aerial vehicle, sweeping robot, or electronic cigarette. [43] The electric device of claim 42, wherein the vehicle is a pure electric vehicle, a hybrid electric vehicle, a plug-in hybrid electric vehicle, an electric bicycle, an electric scooter, an electric golf cart, or an electric truck.