Negative electrode current collector, battery monomer, battery and electric device

Abstract

The invention discloses a negative current collector, a battery monomer, a battery and an electric device, the negative current collector comprises a foam metal matrix, the electrochemical activity mass specific surface area of the foam metal matrix is 2.5 cm < 2 > / g-20 cm < 2 > / g, and the electrochemical activity volume specific surface area of the foam metal matrix is 22 cm < 2 > / cm < 3 >-180 cm < 2 > / cm < 3 >. The negative electrode current collector can slow down dendritic crystal growth, reduce short-circuit risk in the battery, improve the reliability of the battery, prolong the cycle life of the battery and enable the battery to be charged at a high rate.

Description

Technical Field

[0001] This application relates to a negative electrode current collector, a battery cell, a battery, and an electrical device. Background Art

[0002] Compared with ionic batteries, metal batteries can have a higher energy density. However, different from the negative electrodes of ionic batteries, the negative electrodes of metal batteries have the problem of uneven deposition, which affects the reliability and electrochemical performance of metal batteries. Summary of the Invention

[0003] This application provides a negative electrode current collector, a battery cell, a battery, and an electrical device, which can slow down dendrite growth, reduce the risk of internal short circuit in the battery, improve the reliability and cycle life of the battery, and enable the battery to be charged at a high rate.

[0004] In a first aspect, this application provides a negative electrode current collector, which includes a foam metal matrix, and the electrochemically active mass specific surface area of the foam metal matrix is 2.5 cm 2 / g - 20 cm 2 / g, and the electrochemically active volume specific surface area is 22 cm 2 / cm 3 -180 cm 2 / cm 3 .

[0005] Compared with a two-dimensional planar copper foil current collector, the negative electrode current collector of this application has a larger electrochemically active specific surface area. Therefore, when the battery is charged, the negative electrode can have a higher electrochemically active area, can also reduce the current density on the surface of the negative electrode, improve the deposition morphology of the metal, and further can reduce the risk of internal short circuit in the battery, improve the reliability and cycle life of the battery, and can also enable the battery to be charged at a high rate.

[0006] At the same time, the electrochemically active specific surface area of the foam metal matrix is not the larger the better. Generally speaking, the larger the electrochemically active specific surface area of the foam metal matrix, the more pores it contains. Since the deposition of metal has high selectivity, it will preferentially deposit in the pores on the side of the negative electrode close to the separator. In this case, if the electrochemically active specific surface area of the foam metal matrix is too large, the pores on the side of the negative electrode close to the separator will be quickly blocked by the deposited metal. After the pores on the side of the negative electrode close to the separator are blocked, it is difficult or even impossible for the ions in the electrolyte to be replenished to the internal position of the negative electrode, thereby reducing the space utilization rate of the negative electrode. At the same time, it will also cause the wettability of the electrolyte of the negative electrode to become poor, and further cause the cycle performance of the battery to become poor.

[0007] Therefore, in the embodiments of this application, by adjusting the electrochemically active mass specific surface area of the foam metal matrix of the negative electrode current collector to 2.5 cm 2 / g - 20 cm2 / g, the electrochemically active mass specific surface area is 22 cm 2 / cm 3 -180 cm 2 / cm 3 , which can reduce the current density on the negative electrode surface, regulate the metal deposition morphology during charging, and thus can slow down the dendrite growth, reduce the risk of internal short circuit in the battery, improve the reliability and cycle life of the battery, and also enable the battery to perform high-rate charging.

[0008] In some embodiments, the electrochemically active mass specific surface area of the foam metal matrix is 3.2 cm 2 / g - 10 cm 2 / g, and the electrochemically active volume specific surface area is 29 cm 2 / cm 3 -90 cm 2 / cm 3 .

[0009] In some embodiments, the electrochemically active mass specific surface area of the foam metal matrix is 3.2 cm 2 / g - 5 cm 2 / g, and the electrochemically active volume specific surface area is 29 cm 2 / cm 3 -45 cm 2 / cm 3 .

[0010] By further adjusting the electrochemically active mass specific surface area and the electrochemically active volume specific surface area of the foam metal matrix within the above ranges, the battery can have a high Coulomb efficiency on the premise of having good cycle performance and rate performance.

[0011] In some embodiments, the number of pores in the foam metal matrix with a pore diameter between 0.5 times the average pore diameter D avg and 1.5 times the average pore diameter D avg is 80% - 90% of the total number of pores in the foam metal matrix; and / or, the number of pores in the foam metal matrix with a pore diameter less than 0.5 times the average pore diameter D avg is 4.5% - 12% of the total number of pores in the foam metal matrix; and / or, the number of pores in the foam metal matrix with a pore diameter greater than 1.5 times the average pore diameter D avg is 2% - 12% of the total number of pores in the foam metal matrix.

[0012] By adjusting the pore size distribution of the porous metal matrix within the above range, the porous metal matrix can have a high specific surface area of electrochemically active sites, thereby reducing the current density on the surface of the negative electrode, regulating the deposition morphology of the metal, and improving the space utilization rate of the negative electrode, which helps to improve the Coulombic efficiency, cycling performance, and rate performance of the battery; it can also enable the porous metal matrix and the negative electrode current collector to have good electrolyte wettability, and further enable the battery to have a long cycle life.

[0013] In some embodiments, the average pore diameter D of the porous metal matrix avg is 120 μm - 290 μm.

[0014] By adjusting the average pore diameter of the porous metal matrix within the above range, on the one hand, the porous metal matrix can have a high specific surface area of electrochemically active sites, and on the other hand, it can also regulate the deposition morphology of the metal and improve the space utilization rate of the negative electrode, which helps the battery to have both high Coulombic efficiency, good cycling performance, and rate performance.

[0015] In some embodiments, the maximum pore diameter D of the porous metal matrix max is 200 μm - 500 μm.

[0016] In some embodiments, the rib width of the porous metal matrix is 5 μm - 100 μm.

[0017] By adjusting the rib width of the porous metal matrix within the above range, it helps the battery to have both high Coulombic efficiency, good cycling performance, and rate performance.

[0018] In some embodiments, the pore density of the porous metal matrix is 135 PPI - 200 PPI.

[0019] In some embodiments, the porosity of the porous metal matrix is 65% - 91%.

[0020] In some embodiments, the porous metal matrix is an open-cell structure, and the open-cell ratio is greater than or equal to 98%.

[0021] In some embodiments, the thickness of the porous metal matrix is 80 μm - 1000 μm.

[0022] When the thickness of the porous metal matrix is within the above range, it can shorten the ion diffusion path and enhance the deposition and stripping activity and space utilization rate of the negative electrode.

[0023] In some embodiments, the metal elements in the porous metal matrix include one or more of copper, nickel, titanium, aluminum, cobalt, iron, manganese, tin, gold, silver, chromium, zinc, cadmium, lead, platinum, antimony, bismuth, gallium, indium, and palladium.

[0024] In some embodiments, the negative electrode current collector further includes an alkali metal affinity layer on the surface of the foamed metal matrix. The alkali metal affinity layer can regulate the metal deposition morphology and slow down the dendrite growth, thereby improving the rate performance and cycling performance of the battery.

[0025] In some embodiments, the alkali metal affinity layer includes one or more of Cu2O and Li3N.

[0026] In some embodiments, the thickness of the alkali metal affinity layer is 50 nm - 5 μm.

[0027] In a second aspect, the present application provides a battery cell, which includes the negative electrode current collector of the first aspect of the present application.

[0028] In some embodiments, the battery cell includes at least one of a lithium metal battery cell without a negative electrode and a sodium metal battery cell without a negative electrode.

[0029] In a third aspect, the present application provides a battery, which includes the battery cell of the second aspect of the present application.

[0030] In a fourth aspect, the present application provides an electrical device, which includes the battery of the third aspect of the present application, and the battery is used to provide electrical energy.

[0031] The electrical device of the present application includes the battery provided by the present application, and thus has at least the same advantages as the battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required to be used in the embodiments of the present application will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application, and those of ordinary skill in the art can obtain other drawings according to the drawings without creative efforts.

[0033] Figure 1 Schematic diagram showing a battery cell provided by some embodiments of the present application.

[0034] Figure 2 Exploded schematic diagram showing a battery cell provided by some embodiments of the present application.

[0035] Figure 3 Schematic diagram showing a battery module provided by some embodiments of the present application.

[0036] Figure 4 Schematic diagram showing a battery pack provided by some embodiments of the present application.

[0037] Figure 5 is Figure 4 Exploded schematic diagram of the shown battery pack.

[0038] Figure 6 Schematic diagram showing an electrical device provided by some embodiments of the present application.

[0039] In the drawings, the drawings are not necessarily drawn to actual scale. The reference numerals are explained as follows: 1, battery pack; 2, upper box body; 3, lower box body; 4, battery module; 5, battery cell; 51, housing; 52, electrode assembly; 53, cover plate. Detailed implementation manners

[0040] Hereinafter, embodiments of the negative electrode current collector, battery cell, battery, and electrical device of the present application that are specifically disclosed will be described in detail with appropriate reference to the drawings. However, there may be cases where unnecessary details are omitted. For example, there are cases where detailed descriptions of well-known matters and repeated descriptions of actually identical structures are omitted. This is to prevent the following description from becoming unnecessarily lengthy and to facilitate the understanding of those skilled in the art. In addition, the drawings and the following description are provided for those skilled in the art to fully understand the present application and are not intended to limit the subject matter recited in the claims.

[0041] The "range" disclosed in the present application is defined in the form of a lower limit and an upper limit. A given range is defined by selecting a lower limit and an upper limit, and the selected lower limit and upper limit define the boundary of a specific range. The range defined in this way can include or exclude the end values and can be combined arbitrarily, that is, any lower limit can be combined with any upper limit to form a range. For example, if ranges of 60 - 120 and 80 - 110 are listed for a specific parameter, it is understood that ranges of 60 - 110 and 80 - 120 are also contemplated. In addition, if the minimum range values 1 and 2 are listed, and if the maximum range values 3, 4, and 5 are listed, then the following ranges are all contemplated: 1 - 3, 1 - 4, 1 - 5, 2 - 3, 2 - 4, and 2 - 5. In the present application, unless otherwise specified, the numerical range "a - b" represents an abbreviated representation of any real number combination between a and b, where a and b are both real numbers. For example, the numerical range "0 - 5" means that all real numbers between "0 - 5" have been fully listed herein, and "0 - 5" is only an abbreviated representation of these numerical combinations. Additionally, when stating that a certain parameter is an integer ≥2, it is equivalent to disclosing that the parameter is, for example, the integer 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0042] If there is no special instruction, all embodiments and optional embodiments of the present application can be combined with each other to form new technical solutions, and such technical solutions should be considered to be included in the disclosure of the present application.

[0043] Unless otherwise specified, all technical features and optional technical features of the present application can be combined with each other to form new technical solutions, and such technical solutions shall be considered to be included in the disclosure of the present application.

[0044] Unless otherwise specified, all steps of the present application can be carried out sequentially or randomly, preferably sequentially. For example, the method includes steps (a) and (b), which means that the method can include steps (a) and (b) carried out sequentially, or can also include steps (b) and (a) carried out sequentially. For example, it is mentioned that the method may further include step (c), which means that step (c) can be added to the method in any order. For example, the method can include steps (a), (b) and (c), or can also include steps (a), (c) and (b), or can also include steps (c), (a) and (b), etc.

[0045] In the present application, the term "about" is used to describe and illustrate small changes. When used in combination with a numerical value, the term may refer to a change range of ±5% less than or equal to the numerical value, and optionally a change range of less than or equal to 1%.

[0046] In the present application, the terms "a plurality of" and "a variety of" mean two or more than two.

[0047] In the description of the embodiments of the present application, unless otherwise specified, the first feature being "on" or "under" the second feature may be that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, the first feature being "above", "over" and "on top of" the second feature may be that the first feature is directly above or obliquely above the second feature, or merely indicates that the first feature has a higher horizontal height than the second feature. The first feature being "under", "beneath" and "underneath" the second feature may be that the first feature is directly below or obliquely below the second feature, or merely indicates that the first feature has a lower horizontal height than the second feature.

[0048] Unless otherwise specified, the terms used in the present application have the well-known meanings commonly understood by those skilled in the art.

[0049] Unless otherwise specified, the numerical values of the various parameters mentioned in the present application can be measured by various common testing methods in the art. For example, they can be measured according to the testing methods given in the embodiments of the present application. Unless otherwise specified, the test temperature for each parameter is 25°C.

[0050] The battery mentioned in the embodiments of the present application may be a single physical module including one or more battery cells to provide a higher voltage and capacity. For example, the battery mentioned in the present application may include battery cells, battery modules or battery packs, etc.

[0051] A battery cell is the smallest unit that makes up a battery and can independently perform the functions of charging and discharging. The battery cell can be in the shape of a cylinder, a cuboid, or other shapes, etc., and the embodiments of the present application do not limit this. For example, Figure 1 is a battery cell 5 with a cuboid structure as an example.

[0052] When there are multiple battery cells, the multiple battery cells are connected in series, parallel, or in a hybrid connection through a busbar component. In some embodiments, the battery can be a battery module; when there are multiple battery cells, the multiple battery cells are arranged and fixed to form a battery module. In some embodiments, the battery can be a battery pack, and the battery pack includes a box body and battery cells, and the battery cells or battery modules are accommodated in the box body. In some embodiments, the box body can be a part of the chassis structure of a vehicle. For example, a part of the box body can become at least a part of the vehicle floor, or a part of the box body can become at least a part of the crossbeam and longitudinal beam of the vehicle.

[0053] In some embodiments, the battery can be an energy storage device. The energy storage device includes an energy storage container, an energy storage cabinet, etc.

[0054] The battery cell includes an electrode assembly. The electrode assembly can be a wound structure or a stacked structure, and the embodiments of the present application do not limit this.

[0055] The battery cell can also include an outer package, and the outer package can be used to encapsulate the electrode assembly. The outer package can be a hard shell, such as a hard plastic shell, an aluminum shell, a steel shell, etc. The outer package can also be a soft package, such as a bag-type soft package. The material of the soft package can be plastic, such as one or more of polypropylene (PP), polybutylene terephthalate (PBT), and polybutylene succinate (PBS).

[0056] In some embodiments, for example, Figure 2 as shown, the outer package can include a housing 51 and a cover plate 53. The housing 51 can include a bottom plate and side plates connected to the bottom plate, and the bottom plate and the side plates enclose a receiving cavity. The housing 51 has an opening communicating with the receiving cavity, and the cover plate 53 is used to cover the opening to close the receiving cavity. The electrode assembly 52 is encapsulated in the receiving cavity. The number of electrode assemblies 52 included in the battery cell 5 can be one or more, and can be adjusted according to requirements.

[0057] In some embodiments, the battery cells can be assembled into a battery module, and the number of battery cells included in the battery module can be multiple, and the specific number can be adjusted according to the application and capacity of the battery module. Figure 3 is a schematic diagram of a battery module 4 as an example. For example, Figure 3As shown, in the battery module 4, a plurality of battery cells 5 may be arranged in sequence along the length direction of the battery module 4. Of course, they may also be arranged in any other manner. Further, the plurality of battery cells 5 may be fixed by fasteners.

[0058] Optionally, the battery module 4 may further include a housing having an accommodation space, and the plurality of battery cells 5 are accommodated in the accommodation space.

[0059] In some embodiments, the above battery module may also be assembled into a battery pack, and the number of battery modules included in the battery pack may be adjusted according to the application and capacity of the battery pack.

[0060] Figure 4 and Figure 5 is a schematic diagram of a battery pack 1 as an example. As Figure 4 and Figure 5 shown, the battery pack 1 may include a box body and a plurality of battery modules 4 disposed in the box body. The box body includes an upper box body 2 and a lower box body 3. The upper box body 2 is used to cover the lower box body 3 and form a closed space for accommodating the battery modules 4. The plurality of battery modules 4 may be arranged in the box body in any manner.

[0061] The battery cell provided by the embodiment of the present application may be a metal battery cell, for example, it may include a lithium metal battery cell without a negative electrode, a sodium metal battery cell without a negative electrode, etc.

[0062] A battery cell without a negative electrode generally refers to a battery cell that does not actively provide a negative electrode active material layer on the negative electrode side during the manufacturing process of the battery cell. For example, during the manufacturing process of the battery cell, a layer is not provided on the negative electrode by coating or deposition or a negative electrode active material layer is formed by a carbonaceous active material layer. During the first charge, ions obtain electrons on the negative electrode side and deposit on the surface of the negative electrode current collector to form a metal. During discharge, the metal can be converted into ions and return to the positive electrode to realize cyclic charge and discharge. Compared with other battery cells, the battery cell without a negative electrode can obtain a higher energy density because it does not have a negative electrode active material layer. The CB (Cell Balance) value of the battery cell without a negative electrode is usually very small. For example, in some embodiments, the CB value of the battery cell without a negative electrode may be less than or equal to 0.1. The CB value is the unit area capacity of the negative electrode in the battery cell divided by the unit area capacity of the positive electrode. Since the battery cell without a negative electrode does not contain or only contains a small amount of negative electrode active material, the unit area capacity of the negative electrode is small, and thus the CB value is very small, for example, usually less than or equal to 0.1.

[0063] The embodiment of the present application provides a negative electrode current collector. The negative electrode current collector includes a foam metal matrix, and the electrochemically active mass specific surface area of the foam metal matrix is 2.5 cm 2 / g - 20 cm 2 / g, the electrochemically active volume specific surface area is 22 cm 2 / cm 3 -180 cm 2 / cm 3 。

[0064] Currently, the current collector commonly used for the negative electrode is a two-dimensional planar current collector, such as copper foil, and its electrochemically active mass specific surface area is very small, about 0.3 cm 2 / g. When using a two-dimensional planar current collector for a metal battery, the charging rate of the metal battery is often limited. This is because, at a large charging current density, problems will occur in the deposition of the metal, such as accelerated dendrite growth, increased side reactions, and more uneven metal deposition, etc., which will lead to an increased risk of internal short circuit in the battery and accelerated capacity decay.

[0065] The electrochemically active mass specific surface area of the foam metal matrix of the negative electrode current collector provided by the embodiments of the present application is greater than or equal to 2.5 cm 2 / g, and the electrochemically active volume specific surface area is greater than or equal to 22 cm 2 / cm 3 。Therefore, compared with the two-dimensional planar copper foil current collector, the negative electrode current collector of the present application has a larger electrochemically active specific surface area. Thus, when the battery is charged, the negative electrode can have a higher electrochemically active area, and the current density on the surface of the negative electrode can also be reduced, the deposition morphology of the metal can be improved, and further the risk of internal short circuit in the battery can be reduced, the reliability and cycle life of the battery can be enhanced, and the battery can also be charged at a high rate.

[0066] At the same time, the electrochemically active specific surface area of the foam metal matrix is not the larger the better. Generally speaking, the larger the electrochemically active specific surface area of the foam metal matrix, the more pores it contains. Since the deposition of the metal has high selectivity, it will preferentially deposit in the pores on the side of the negative electrode close to the separator. In this case, if the electrochemically active specific surface area of the foam metal matrix is too large, the pores on the side of the negative electrode close to the separator will be quickly blocked by the deposited metal. After the pores on the side of the negative electrode close to the separator are blocked, it is difficult or even impossible for the ions in the electrolyte to be replenished to the internal position of the negative electrode, thereby reducing the space utilization rate of the negative electrode. At the same time, it will also lead to poor wettability of the electrolyte of the negative electrode, and further lead to poor cycle performance of the battery.

[0067] Therefore, the embodiments of the present application adjust the electrochemically active mass specific surface area of the foam metal matrix of the negative electrode current collector to be 2.5 cm 2 / g - 20 cm 2 / g, and the electrochemically active volume specific surface area is 22 cm 2 / cm 3 -180 cm 2 / cm 3, it can reduce the current density on the surface of the negative electrode, regulate the morphology of metal deposition during charging, thereby slowing down dendrite growth, reducing the risk of internal short circuit in the battery, improving the reliability and cycle life of the battery, and enabling the battery to be charged at a high rate.

[0068] Optionally, the electrochemically active mass specific surface area of the foam metal matrix can be 3.2 cm 2 / g - 10 cm 2 / g, and the electrochemically active volume specific surface area can be 29 cm 2 / cm 3 - 90 cm 2 / cm 3 .

[0069] In some embodiments, the electrochemically active mass specific surface area of the foam metal matrix can be 3.2 cm 2 / g - 5 cm 2 / g, and the electrochemically active volume specific surface area can be 29 cm 2 / cm 3 - 45 cm 2 / cm 3 .

[0070] When the electrochemically active specific surface area of the foam metal matrix increases, more active ions are consumed to activate the deposition sites on the surface of the negative electrode during the first charge of the battery, which will reduce the Coulombic efficiency of the first cycle of the battery. Thus, by further adjusting the electrochemically active mass specific surface area and electrochemically active volume specific surface area of the foam metal matrix within the above ranges, the battery can have a high Coulombic efficiency on the premise of having good cycle performance and rate performance.

[0071] The electrochemically active mass specific surface area and electrochemically active volume specific surface area of the foam metal matrix can be tested as follows: Cut the foam metal matrix into small round pieces with a diameter of 20 mm as samples, and prepare a button battery with a lithium metal sheet as the counter electrode. The electrolyte salt of the electrolyte of the button battery is LiFSI, with a concentration of 1 mol / L. The solvent of the electrolyte uses ethylene glycol dimethyl ether (DME), and the probe molecule uses ferrocene with a concentration of 50 mmol / L. The separator of the button battery can use a PE film with a thickness of 12 μm. At 25 °C, after the assembled button battery is left standing for 12 h, it is discharged at a constant voltage of 2.5 V until the current drops to 0.0025 mA / cm 2, perform cyclic voltammetry scans in the range of 2.5V - 3.4V at sweep rates of 3mV / s, 2mV / s, 1mV / s, and 0.5mV / s, and read the peak currents during the forward scans at each sweep rate. Use the linear regression method to perform a linear regression on the peak current and the square root of the sweep rate to obtain the slope; calculate the electrochemically active specific surface area of the foam metal substrate according to the Randles - Sevick equation. The test instrument can be a Solartron electrochemical workstation from the United Kingdom.

[0072] By adjusting the pore size, pore size distribution, porosity, number of pores, rib width, etc. of the foam metal substrate, the electrochemically active specific surface area of the foam metal substrate can be adjusted.

[0073] In some embodiments, the foam metal substrate has an open - cell structure. Optionally, the open - cell rate can be greater than or equal to 98%.

[0074] In some embodiments, in the foam metal substrate, the number of pores with a pore size between 0.5 times the average pore size D avg and 1.5 times the average pore size D avg can be 72% - 90% of the total number of pores in the foam metal substrate, and can optionally be 80% - 90%.

[0075] In some embodiments, in the foam metal substrate, the number of pores with a pore size less than 0.5 times the average pore size D avg can be 4.5% - 15% of the total number of pores in the foam metal substrate, and can optionally be 4.5% - 12%.

[0076] In some embodiments, in the foam metal substrate, the number of pores with a pore size greater than 1.5 times the average pore size D avg can be 2% - 15% of the total number of pores in the foam metal substrate, and can optionally be 2% - 12%, 5% - 12%.

[0077] By adjusting the pore size distribution of the foam metal substrate within the above range, the foam metal substrate can have a high electrochemically active specific surface area, thereby reducing the current density on the negative electrode surface, adjusting the deposition morphology of the metal, and improving the space utilization rate of the negative electrode, which helps to improve the Coulomb efficiency, cycle performance, and rate performance of the battery; it can also make the foam metal substrate and the negative electrode current collector have good electrolyte wettability, and further enable the battery to have a long cycle life.

[0078] In some embodiments, in the foam metal substrate, the number of pores with a pore size between 0.5 times the average pore size D avg and 1.5 times the average pore size D avg can be 80% - 90% of the total number of surface pores in the foam metal substrate. The number of pores with a pore size less than 0.5 times the average pore size D avgThe number of the holes can be 4.5%-12% of the number of all the surface holes in the foam metal matrix, and the pore diameter in the foam metal matrix is greater than 1.5 times the average pore diameter D avg The number of the holes can be 5%-12% of the number of all the surface holes in the foam metal matrix.

[0079] In some embodiments, the average pore diameter D of the foam metal matrix avg can be 120 μm-290 μm, optionally 180 μm-290 μm, 200 μm-290 μm, 230 μm-290 μm, 230 μm-280 μm.

[0080] When other conditions are the same, the smaller the average pore diameter of the foam metal matrix, the larger the electrochemically active specific surface area of the foam metal matrix. Since the deposition of the metal has high selectivity, it will preferentially deposit in the holes on the side of the negative electrode close to the separator. In this case, the smaller the average pore diameter of the foam metal matrix, the holes on the side of the negative electrode close to the separator will be quickly blocked by the deposited metal. After the holes on the side of the negative electrode close to the separator are blocked, it is difficult or even impossible for the ions in the electrolyte to supplement to the inner position of the negative electrode, thereby reducing the space utilization rate of the negative electrode and at the same time causing poor wettability of the electrolyte of the negative electrode.

[0081] By adjusting the average pore diameter of the foam metal matrix within the above range, on the one hand, the foam metal matrix can have a high electrochemically active specific surface area, and on the other hand, the deposition morphology of the metal can be adjusted and the space utilization rate of the negative electrode can be improved, thereby helping the battery to have both high Coulomb efficiency, good cycle performance and rate performance.

[0082] In some embodiments, the maximum pore diameter D of the foam metal matrix max can be 200 μm-500 μm, 250 μm-480 μm, 300 μm-480 μm, 350 μm-480 μm, 400 μm-480 μm, 420 μm-480 μm.

[0083] The foam metal matrix is a porous material formed by the connection of rib filaments, and its microstructure can be composed of rib filaments and pores. In some embodiments, the width of the rib filaments of the foam metal matrix can be 5 μm-100 μm, optionally 5 μm-50 μm, more optionally 10 μm-50 μm, 15 μm-50 μm, 20 μm-50 μm, 25 μm-50 μm.

[0084] When the battery is charging, metal can be deposited on the ribs. When the average pore size of the foam metal matrix is ​​the same, a larger rib width can reduce the current density on the negative electrode surface. At low current density, the nucleation diameter of metal deposition increases, and a larger nucleation diameter can slow down dendrite growth and reduce the repeated generation of solid electrolyte interface film (SEI), thereby improving the coulombic efficiency, cycle performance and rate performance of the battery. At the same time, the rib width is not the larger the better. Ribs that are too wide will occupy the volume that can be used for metal deposition, thereby reducing the energy density of the battery. In addition, in the daily operating conditions of the battery, a larger current tends to be used to charge the battery, and a current that is too small is usually difficult to meet user needs.

[0085] Therefore, by adjusting the rib width of the foam metal matrix within the above range, the battery can have high coulombic efficiency, good cycle performance and rate performance.

[0086] The pore size, pore size distribution, and rib width of the foam metal matrix can be tested as follows: randomly select 10 areas on the foam metal matrix, observe the sample using an optical microscope, take photos at a magnification of 200 times, measure and mark the pore size and rib width of all surface pores on the surface of the foam metal matrix. There should be at least 20 surface pores on the photo corresponding to each area.

[0087] The pore size refers to the average diameter of the pores, and the average diameter refers to the arithmetic mean of the longest diameter and the shortest diameter of the pores.

[0088] The rib width refers to the width of the ribs between holes.

[0089] The average pore size of all surface pores is taken as the average pore size D of the foam metal matrix. avg .

[0090] The maximum pore size of all surface pores is taken as the maximum pore size D of the foam metal matrix. max .

[0091] The number of all surface pores is taken as the denominator, and the pore diameter is 0.5 times the average pore diameter D. avg and 1.5 times the average pore diameter D avg The number of pores between the two is taken as the numerator, and the pore diameter is calculated at 0.5 times the average pore diameter D avg and 1.5 times the average pore diameter D avg The proportion of holes.

[0092] The number of all surface pores is taken as the denominator, and the pore diameter is less than 0.5 times the average pore diameter D avg The number of pores is taken as the numerator, and the pore diameter is calculated to be less than 0.5 times the average pore diameter D avg The proportion of holes.

[0093] Using the total number of all obtained surface pores as the denominator, and the number of pores with a pore diameter greater than 1.5 times the average pore diameter D avg as the numerator, calculate the proportion of the number of pores with a pore diameter greater than 1.5 times the average pore diameter D avg .

[0094] Using the average value of the obtained rib wire width as the rib wire width of the foam metal matrix.

[0095] In some embodiments, the pore density of the foam metal matrix can be 135 PPI - 260 PPI, optionally 135 PPI - 200 PPI, 135 PPI - 180 PPI, 150 PPI - 180 PPI. PPI, Pores Per Linear Inch, represents the average number of pores per unit inch (i.e., 2.54 cm) in length.

[0096] The pore density of the foam metal matrix can be tested with reference to GB / T 20251 - 2006. For example, it can be inspected using an optical microscope with a magnification of 100 times. When testing, 10 regions can be randomly selected on the foam metal matrix, and the test results are averaged.

[0097] In some embodiments, the porosity of the foam metal matrix can be 65% - 91%, optionally 70% - 88%, 76% - 88%, 80% - 88%, 82% - 88%.

[0098] The porosity of the foam metal matrix can be measured using the kerosene displacement method. The porosity P of the foam metal matrix = (V0 - V) / V0 × 100%. V0 represents the volume of the foam metal matrix in the natural state (or apparent volume), V0 = t × s. t represents the thickness of the foam metal matrix, in cm; s represents the area of the foam metal matrix, in cm 2 . V represents the absolute dense volume of the foam metal matrix, which can be measured using the kerosene displacement method.

[0099] In some embodiments, the thickness of the foam metal matrix can be 80 μm - 1000 μm, optionally 100 μm - 600 μm.

[0100] The thickness of the foam metal matrix can be measured using a micrometer with a precision of 0.01 mm, and the average value is taken by measuring 10 points.

[0101] When the thickness of the foam metal matrix is within the above range, the ion diffusion path can be shortened, and the deposition and stripping activity and space utilization rate of the negative electrode can be improved.

[0102] In some embodiments, the metal elements in the metallic foam matrix may include one or more of copper, nickel, titanium, aluminum, cobalt, iron, manganese, tin, gold, silver, chromium, zinc, cadmium, lead, platinum, antimony, bismuth, gallium, indium, palladium, and may optionally include one or more of copper and nickel.

[0103] In some embodiments, the negative current collector may further include an alkali metal affinity layer on the surface of the metallic foam matrix. The alkali metal affinity layer can regulate the metal deposition morphology and slow down the dendrite growth, thereby improving the rate performance and cycling performance of the battery.

[0104] Optionally, the alkali metal affinity layer may include one or more of metal oxides, non-metal oxides, metal sulfides, non-metal sulfides, metal nitrides, non-metal nitrides, and may optionally include one or more of Cu2O and Li3N.

[0105] Optionally, the thickness of the alkali metal affinity layer may be 50 nm - 5 μm, and may optionally be 1 μm - 3 μm.

[0106] The metallic foam matrix can be prepared by electrodeposition.

[0107] In some embodiments, the method for preparing the metallic foam matrix includes the following steps: providing a foam polymer material; sequentially performing chemical deposition and electrodeposition using the foam polymer material as a matrix to deposit a metal material on the foam polymer material, and then performing a thermal reduction treatment to remove the foam polymer material to obtain the metallic foam matrix.

[0108] Optionally, in some embodiments, the foam polymer material may include any one of polyurethane foam, melamine foam, polyethylene foaming material (EPE), polypropylene foaming material (EPP), polystyrene foam material (EPS), expandable polyethylene and styrene polymer (EPO), and chloroprene rubber foaming material (CR foam).

[0109] Optionally, in some embodiments, the porosity of the foam polymer material may be 65% - 95%, and may optionally be 70% - 92%, 76% - 92%, 80% - 92%, 82% - 92%.

[0110] Optionally, in some embodiments, the pore density of the foam polymer material may be 135 PPI - 260 PPI, and may optionally be 135 PPI - 200 PPI.

[0111] Optionally, in some embodiments, the average pore diameter D of the foam polymer material avg may be 120 μm - 400 μm, and may optionally be 180 μm - 400 μm, 200 μm - 400 μm, 230 μm - 400 μm, 230 μm - 400 μm.

[0112] Optionally, in some embodiments, the maximum pore diameter D of the foam polymer material max may be 200 μm - 600 μm, optionally 250 μm - 600 μm, 300 μm - 600 μm, 350 μm - 600 μm, 400 μm - 600 μm, 420 μm - 600 μm.

[0113] Optionally, in some embodiments, the number of pores in the foam polymer material with pore diameters between 0.5 times the average pore diameter D avg and 1.5 times the average pore diameter D avg may be 72% - 90% of the total number of pores in the foam polymer material, optionally 80% - 90%. The number of pores in the foam polymer material with pore diameters less than 0.5 times the average pore diameter D avg may be 4.5% - 15% of the total number of pores in the foam polymer material, optionally 4.5% - 12%. The number of pores in the foam polymer material with pore diameters greater than 1.5 times the average pore diameter D avg may be 2% - 15% of the total number of pores in the foam polymer material, optionally 2% - 12%.

[0114] Optionally, in some embodiments, the thickness of the foam polymer material may be 80 μm - 1000 μm, optionally 100 μm - 600 μm.

[0115] The test method of the foam polymer material may refer to the test method of the above-mentioned foam metal matrix.

[0116] The foam polymer material can be obtained commercially or can be prepared according to the preparation methods known in the art. The blowing agent can be a physical blowing agent and / or a chemical blowing agent.

[0117] The physical blowing agent expands the polymer through the change of the physical state of the blowing agent. The physical blowing agent may include one or more of supercritical carbon dioxide, supercritical nitrogen, n-pentane, isopentane, n-butane, isobutane, n-hexane, n-heptane, cyclopentane, propane.

[0118] The chemical blowing agent, also known as a decomposable blowing agent, can expand the polymer by releasing gas through chemical changes during the foaming process. The chemical blowing agent may include one or more of azo compounds, sulfonyl hydrazide compounds, nitroso compounds.

[0119] Optionally, before chemical deposition, the foam polymer material can also be pretreated.

[0120] In some embodiments, the pretreatment may include degreasing, roughening, sensitizing, activating, and peptizing steps carried out in sequence.

[0121] The roughening treatment can open the blind holes in the foam polymer material; it can also form many microscopic pitting corrosion on the surface of the foam polymer material. During chemical deposition, metal particles will deposit in these pitting corrosion; it can also generate hydrophilic groups on the inner and outer surfaces of the foam polymer material to facilitate subsequent processing.

[0122] The purpose of the sensitization treatment is to form a layer of easily oxidizable substances on the surface of the foam polymer material. These easily oxidizable substances are oxidized during the activation treatment, while the activator is reduced to catalytic nuclei and remains on the surface of the foam polymer material.

[0123] The activation treatment is to immerse the foam polymer material after the sensitization treatment in a solution containing a noble metal compound with catalytic activity for re-treatment, so that a noble metal layer with catalytic activity is formed on the surface of the foam polymer material to serve as a catalyst for the redox reaction of electroless plating. The essence of activation is the reduction reaction of noble metals. The noble metal particles formed by reduction are generally in a gel state and have a high surface activity, and can be adsorbed on the surface of the foam polymer material.

[0124] The purpose of the peptization treatment is to remove the gel layer formed by the activation treatment, so that the noble metal atoms are fully exposed, so that they can produce a better catalytic effect during the chemical deposition stage.

[0125] Optionally, the roughening solution can be a sulfuric acid solution containing potassium permanganate.

[0126] Optionally, the sensitization solution can be a hydrochloric acid solution containing stannous chloride.

[0127] Optionally, the activation solution can be a hydrochloric acid solution containing palladium chloride or an ammonia water solution containing silver nitrate.

[0128] Optionally, the peptization solution can be a formaldehyde solution or a hydrochloric acid solution.

[0129] The foam polymer material is an insulating material and cannot be directly electroplated with metal. The purpose of chemical deposition is to deposit a thin metal film on the foam polymer material to make the foam polymer material conductive, so that the coating structure obtained by electroplating can be more uniform and the surface can be smoother.

[0130] Chemical deposition can adopt the plating solution formulations known in the art. Taking the chemical deposition of copper as an example, the plating solution can include: copper sulfate, formaldehyde, sodium potassium tartrate, sodium hydroxide, etc.

[0131] In order to further reduce costs, the metal deposited chemically can be different from the metal deposited electroplated. For example, it can be a base metal with a lower price. Taking the electroplating of copper as an example, the metal deposited chemically can be nickel with a lower price.

[0132] Electrodeposition can use plating solution formulations known in the art. Taking electrodepositing copper as an example, the plating solution can include: copper sulfate, sulfuric acid, potassium chloride, polyethylene glycol, etc.

[0133] By adjusting the process parameters of electrodeposition, such as deposition time, voltage, current density and other parameters, the deposition amount of the metal can be adjusted, and thus the areal density of the foam metal matrix can be adjusted.

[0134] The purpose of the thermal reduction treatment is to remove the foam polymer material.

[0135] Optionally, the thermal reduction gas for the thermal reduction treatment can be a mixture of hydrogen and argon or a mixture of hydrogen and nitrogen.

[0136] Optionally, the temperature of the thermal reduction treatment can be 650°C - 850°C.

[0137] [Positive electrode tab]

[0138] The battery cell includes a positive electrode tab.

[0139] In some embodiments, the positive electrode tab includes a positive current collector and a positive electrode film layer disposed on at least one surface of the positive current collector and including a positive active material. For example, the positive current collector has two surfaces opposite to each other in its own thickness direction, and the positive electrode film layer is disposed on either or both of the two opposite surfaces of the positive current collector.

[0140] In some embodiments, the positive active material includes a material capable of deintercalating and intercalating lithium.

[0141] As an example, the positive active material can include, but is not limited to, one or more of lithium transition metal oxides, metal chalcogenides, lithium-containing phosphates, and their respective modified compounds. Examples of lithium transition metal oxides can include, but are not limited to, one or more of lithium cobalt oxide, lithium nickel oxide, lithium manganese oxide, lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, lithium nickel cobalt manganese oxide, lithium nickel cobalt aluminum oxide, lithium titanium oxide, and their respective modified compounds. The lithium transition metal oxides can include, but are not limited to, layered structures and spinel structures. Examples of lithium-containing phosphates can include, but are not limited to, lithium iron phosphate, a composite material of lithium iron phosphate and carbon, lithium manganese phosphate, a composite material of lithium manganese phosphate and carbon, lithium manganese iron phosphate, a composite material of lithium manganese iron phosphate and carbon, and their respective modified compounds.

[0142] In some embodiments, in order to further improve the energy density of the battery, the positive active material can include a general formula of Li a Ni b Co c M d O e D fOne or more of lithium transition metal oxides and modified compounds thereof. 0.8≤a≤1.2, 0.5≤b<1, 0<c<1, 0<d<1, 1≤e≤2, 0≤f≤1, M may include but is not limited to one or more of Ge, Mo, Sn, Mn, Al, Zr, Zn, Cu, Cr, Mg, Fe, V, Ti and B, and D may include but is not limited to one or more of N, F, S and Cl.

[0143] In some embodiments, the positive electrode active material may include both lithium transition metal oxide and lithium-containing phosphate, thereby facilitating obtaining a battery having both large capacity and high reliability.

[0144] As an example, the positive electrode active material may include but is not limited to LiCoO2, LiNiO2, LiMnO2, LiNi 1 / 2 Mn 1 / 2O2, LiMn2O4, Li 4 / 3 Ti 5 / 3 O4、LiNi 1 / 2 Mn 1 / 2 O2、LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2(NCM333), LiNi 0.5 Co 0.2 Mn 0.3 O2(NCM523), LiNi 0.6 Co 0.2 Mn 0.2 O2(NCM622), LiNi 0.8 Co 0.1 Mn 0.1 O2(NCM811), LiNi 0.80 Co 0.15 Al 0.05 O2, LiFePO4, LiMnPO4, Li 1.13 Ti 0.57 Fe 0.3 One or more of S2.

[0145] In some embodiments, the positive electrode active material includes a material capable of extracting and embedding sodium. For example, the positive electrode active material may include, but is not limited to, one or more of layered transition metal oxides (including but not limited to P2 type, O3 type, etc.), polyanionic materials (such as phosphates, fluorophosphates, pyrophosphates, sulfates, etc.), and Prussian materials.

[0146] In some embodiments, as examples, the positive electrode active material may include but is not limited to NaFeO2, NaCoO2, NaCrO2, NaMnO2, NaNiO2, Na 0.67One or more of MO₂ (M includes at least two of Fe, Co, Cr, Mn, Ni, V, Ti, and Mo), NaMO₂ (M includes at least two of Fe, Co, Ni, V, Ti, and Mo), NaFePO₄, NaMnPO₄, NaCoPO₄, Na₄Fe₃(PO₄)₂O₇, Na₃V₂(PO₄)₂F₃, Na₃V₂(PO₄)₃, Prussian blue, Prussian white, and their respective modified compounds.

[0147] The modified compounds of the above positive electrode active materials can be doping modification and / or surface coating modification of the positive electrode active materials.

[0148] In some embodiments, the positive electrode film layer may further optionally include a positive electrode conductive agent. As an example, the positive electrode conductive agent may include, but is not limited to, one or more of superconducting carbon, conductive graphite, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.

[0149] In some embodiments, the positive electrode film layer may further optionally include a positive electrode binder. As an example, the positive electrode binder may include, but is not limited to, one or more of polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), vinylidene fluoride-tetrafluoroethylene-propylene terpolymer, vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene terpolymer, tetrafluoroethylene-hexafluoropropylene copolymer, polyethylene oxide, fluorinated acrylate resin, styrene-butadiene rubber (SBR), water-soluble unsaturated resin SR-1B, water-based acrylic resin (for example, polyacrylic acid PAA, polymethacrylic acid PMAA, sodium polyacrylate PAAS), polyacrylamide (PAM), polyvinyl alcohol (PVA), sodium alginate (SA), and carboxymethyl chitosan (CMCS).

[0150] In some embodiments, the positive electrode current collector can be a metal foil or a composite current collector. As an example of the metal foil, aluminum foil can be used. The composite current collector may include a polymer material base layer and a metal material layer formed on at least one surface of the polymer material base layer. As an example, the metal material may include, but is not limited to, one or more of aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver, and silver alloy. As an example, the polymer material base layer may include, but is not limited to, one or more of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), and polyethylene (PE).

[0151] The positive electrode film layer is usually formed by coating a positive electrode slurry on a positive electrode current collector and then drying and cold pressing. The positive electrode slurry is usually formed by dispersing a positive electrode active material, an optional positive electrode conductive agent, an optional positive electrode binder, and any other components in a solvent and stirring evenly. The solvent can be N-methylpyrrolidone (NMP), but is not limited thereto.

[0152] [Electrolyte]

[0153] The battery cell includes an electrolyte.

[0154] In some embodiments, the electrolyte uses an electrolytic solution, and the electrolytic solution includes an electrolyte salt and an organic solvent.

[0155] In some embodiments, the electrolytic solution includes anions, and the anions can include one or more of bis(fluorosulfonyl)imide anion (FSI - ), bis(trifluoromethylsulfonyl)imide anion (TFSI - ), bis(oxalato)borate anion (BOB - ), difluoro(oxalato)borate anion (DFOB - ), difluoro(dioxalato)phosphate anion (DFOP - ), tetrafluoro(oxalato)phosphate anion (TFOP - ), difluorophosphate anion (PO2F2 - ), hexafluorophosphate anion (PF6 - ), tetrafluoroborate anion (BF4 - ), hexafluoroarsenate anion (AsF6 - ), trifluoromethanesulfonate anion (CF3SO3 - ).

[0156] In some embodiments, the electrolytic solution includes cations, and the cations can include one or more of lithium ions and sodium ions.

[0157] In some embodiments, the concentration of the electrolyte salt can be 0.3 mol / L or more, optionally 0.7 mol / L or more, and further can be 4 mol / L or less, optionally 2.5 mol / L or less, 1.7 mol / L or less. When the concentration of the electrolyte salt is within the above range, the electrolytic solution can have appropriate ionic conductivity.

[0158] The organic solvent can include, but is not limited to, one or more of esters, ethers, sulfones, nitriles, etc. Esters can include, but are not limited to, one or more of carbonates, phosphates, carboxylates, sulfates, sulfonates, etc. Carbonates can include cyclic carbonates and / or linear carbonates. Optionally, the carbonates can include both cyclic carbonates and linear carbonates. Linear carbonates can include low-viscosity polar linear carbonates, aliphatic branched carbonates, etc.

[0159] As an example, the organic solvent may include, but is not limited to, ethylene carbonate (EC), propylene carbonate (PC), butylene carbonate, ethyl methyl carbonate (EMC), diethyl carbonate (DEC), dimethyl carbonate (DMC), dipropyl carbonate (DPC), methyl propyl carbonate (MPC), ethyl propyl carbonate (EPC), butylene sulfite (BC), fluoroethylene carbonate (FEC), methyl formate (MF), methyl acetate (MA), ethyl acetate (EA), propyl acetate (PA), methyl propionate (MP), ethyl propionate (EP), propyl propionate (PP), methyl butyrate (MB), ethyl butyrate (EB), 1,4-butyrolactone (GBL), sulfolane (SF), dimethyl sulfone (MSM), ethyl methyl sulfone (EMS), diethyl sulfone (ESE), tetraethylene glycol dimethyl ether (TEGDME), ethylene glycol dimethyl ether (DME), 1,3-dioxolane (DOL), trimethyl phosphate, 3-methoxypropionitrile, H(CF2)2OCH3, C4F9OCH3, H(CF2)2OCH2CH3, H(CF2)2OCH2CF3, H(CF2)2CH2O(CF2)2H, CF3CHFCF2OCH3, CF3CHFCF2OCH2CH3, 2-trifluoromethylhexafluoropropyl methyl ether, 2-trifluoromethylhexafluoropropyl ethyl ether, 2-trifluoromethylhexafluoropropyl propyl ether, 3-trifluoromethyloctafluorobutyl methyl ether, 3-trifluoromethyloctafluorobutyl ethyl ether, 3-trifluoromethyloctafluorobutyl propyl ether, 4-trifluoromethyldecafluoropentyl methyl ether, 4-trifluoromethyldecafluoropentyl ethyl ether, 4-trifluoromethyldecafluoropentyl propyl ether, 5-trifluoromethyldodecafluorohexyl methyl ether, 5-trifluoromethyldodecafluorohexyl ethyl ether, 5-trifluoromethyldodecafluorohexyl propyl ether, 6-trifluoromethyltetradecafluoroheptyl methyl ether, 6-trifluoromethyltetradecafluoroheptyl ethyl ether, 6-trifluoromethyltetradecafluoroheptyl propyl ether, 7-trifluoromethylhexadecafluorooctyl methyl ether, 7-trifluoromethylhexadecafluorooctyl ethyl ether, 7-trifluoromethylhexadecafluorooctyl propyl ether, or one or more of them.

[0160] In some embodiments, the electrolyte may also optionally include additives. For example, the additives may include negative electrode film-forming additives, may also include positive electrode film-forming additives, and may also include additives that can improve certain battery performances, such as additives for improving the overcharge performance of the battery, additives for improving the high-temperature performance of the battery, additives for improving the low-temperature power performance of the battery, and the like.

[0161] [Separator film]

[0162] The battery cell may also include a separator film. The separator film is located between the positive electrode and the negative electrode and mainly functions to prevent internal short circuit.

[0163] There is no particular limitation on the type of the separator membrane in this application, and any well-known porous structure separator membrane with good chemical stability and mechanical stability can be selected.

[0164] In some embodiments, the material of the separator membrane may include, but is not limited to, one or more of glass fiber, non-woven fabric, polyethylene, polypropylene, and polyvinylidene fluoride. The separator membrane can be a single-layer film or a multi-layer composite film. When the separator membrane is a multi-layer composite film, the materials of each layer can be the same or different.

[0165] The preparation method of the battery cell is well-known. In some embodiments, the positive electrode, the separator membrane, the negative electrode, and the electrolyte can be assembled to form a battery cell. As an example, the positive electrode, the separator membrane, and the negative electrode can be formed into an electrode assembly through a winding process and / or a stacking process, the electrode assembly is placed in an outer package, dried, and then the above-mentioned electrolyte is injected, and after processes such as vacuum packaging, standing, and formation, a battery cell is obtained. Multiple battery cells can further form a battery module through series connection, parallel connection, or series-parallel connection. Multiple battery modules can further form a battery pack through series connection, parallel connection, or series-parallel connection. In some embodiments, multiple battery cells can also directly form a battery pack.

[0166] The embodiments of this application also provide an electrical device, and the electrical device includes the battery provided by the embodiments of this application. The battery can be used as the power source of the electrical device or as the energy storage unit of the electrical device. The electrical device can be, but is not limited to, a mobile device (such as a mobile phone, a tablet computer, a laptop computer, etc.), an electric vehicle (such as a pure electric vehicle, a hybrid electric vehicle, a plug-in hybrid electric vehicle, an electric bicycle, an electric scooter, an electric golf cart, an electric truck, etc.), an electric train, a ship, a satellite, an energy storage system, etc.

[0167] The electrical device can select the type of the battery according to its usage requirements, such as a battery cell, a battery module, or a battery pack.

[0168] Figure 6 It is a schematic diagram of an electrical device as an example. The electrical device is a pure electric vehicle, a hybrid electric vehicle, or a plug-in hybrid electric vehicle, etc. In order to meet the requirements of the electrical device for high power and high energy density, a battery pack or a battery module can be adopted.

[0169] Another example of the electrical device can be a mobile phone, a tablet computer, a laptop computer, etc. This electrical device usually requires being thin and light, and a battery cell can be adopted as the power source.

[0170] Example

[0171] The following examples describe more specifically the content disclosed in the present application. These examples are for illustrative purposes only, as various modifications and variations within the scope of the present application disclosure are obvious to those skilled in the art. Unless otherwise stated, all parts, percentages, and ratios reported in the following examples are based on weight, and all reagents used in the examples are commercially available or synthesized according to conventional methods and can be used directly without further treatment, and all instruments used in the examples are commercially available.

[0172] Example 1

[0173] Using commercially available polyurethane foam as the substrate, degreasing, roughening, sensitizing, activating, degluing, chemical deposition, electroplating, and thermal reduction treatments were sequentially carried out to obtain a foam metal substrate.

[0174] The thickness of the polyurethane foam is 120 μm, the pore density is 135 PPI, the porosity is 80%-95%, the average pore diameter is about 290 μm, the maximum pore diameter is about 480 μm, and the proportion of the number of pores in the polyurethane foam with a pore diameter between 0.5 times the average pore diameter D avg and 1.5 times the average pore diameter D avg is about 83.3%, the proportion of the number of pores with a pore diameter less than 0.5 times the average pore diameter D avg is about 5.7%, and the proportion of the number of pores with a pore diameter greater than 1.5 times the average pore diameter D avg is about 11.0%.

[0175] (1) Degreasing

[0176] The polyurethane foam was immersed in a degreasing solution at 40 °C for 10 min, and then cleaned with deionized water and squeezed dry.

[0177] The formula of the degreasing solution is: sodium carbonate 30 g / L, sodium phosphate 30 g / L, sodium dodecyl sulfate 15 g / L, and the solvent is water.

[0178] (2) Roughening

[0179] The degreased polyurethane foam was immersed in a roughening solution at 35 °C for 5 min, and after completion, it was cleaned with deionized water and squeezed dry.

[0180] The formula of the roughening solution is: potassium permanganate 13 g / L, concentrated sulfuric acid 7 mL / L, and the solvent is water.

[0181] (3) Sensitizing

[0182] The roughened polyurethane foam was immersed in a roughening solution at 25 °C for 5 min.

[0183] The formulation of the sensitizing solution is: stannous chloride 20 g / L, hydrochloric acid with a mass fraction of 36% 40 mL / L, and tin grains are added to the sensitizing solution.

[0184] (4) Activation

[0185] The sensitized polyurethane foam is washed with deionized water and then immersed in the activation solution at 25 °C for 5 min.

[0186] The formulation of the activation solution is: silver nitrate 3 g / L, ammonia water with a mass fraction of 25% 5 mL / L, and the solvent is water.

[0187] (5) Debinding

[0188] The activated polyurethane foam is immersed in an aqueous hydrochloric acid solution with a mass fraction of 14% for 2 min.

[0189] (6) Chemical deposition

[0190] The debound polyurethane foam is placed in the electroless plating solution at 60 °C and immersed for 5 min.

[0191] The formulation of the electroless plating solution is: copper sulfate 10 g / L, formaldehyde 20 mL / L, sodium potassium tartrate 3 g / L, EDTA 40 g / L, sodium hydroxide 10 g / L, and the solvent is water.

[0192] (7) Electrochemical deposition

[0193] An electrolytic cell is made with a DC power supply device. The polyurethane foam after chemical deposition is washed clean with deionized water and then immersed in the electroplating solution as the cathode, and a metal copper sheet is used as the anode for electrochemical plating. The copper deposition amount of the electrochemical plating is about 230 g / cm 2 .

[0194] The formulation of the electroplating solution is: copper sulfate 70 g / L, sulfuric acid 25 ml / L, potassium chloride 0.6 ml / L, polyethylene glycol 0.003 g / L, and the solvent is water.

[0195] (8) Thermal reduction

[0196] The polyurethane foam after electrochemical plating is washed clean with deionized water and anhydrous ethanol and then placed in a tube furnace. The pressure is evacuated to below 100 Pa, and then a hydrogen-argon mixture with a hydrogen volume ratio of 10% is introduced until the pressure in the furnace tube reaches atmospheric pressure. The outlet valve is opened, and the pressure in the furnace tube is kept the same as the atmospheric pressure. The heating rate is set at 5 °C / min, the temperature is raised to 700 °C, held for 2 h, and then naturally cooled. After taking out of the furnace, a foam metal matrix without polyurethane foam, that is, foam copper, is obtained.

[0197] Example 2

[0198] The preparation method of the metal foam matrix is similar to that of Example 1, except that the parameters of the polyurethane foam matrix are different.

[0199] The thickness of the polyurethane foam is 120 μm, the pore density is 150 PPI, the porosity is 80%-95%, the average pore diameter is about 280 μm, the maximum pore diameter is about 480 μm. The proportion of the number of pores with pore diameters between 0.5 times the average pore diameter D avg and 1.5 times the average pore diameter D avg is about 83.9%, the proportion of the number of pores with pore diameters less than 0.5 times the average pore diameter D avg is about 4.7%, and the proportion of the number of pores with pore diameters greater than 1.5 times the average pore diameter D avg is about 11.4%.

[0200] Example 3

[0201] The preparation method of the metal foam matrix is similar to that of Example 1, except that the parameters of the polyurethane foam matrix are different.

[0202] The thickness of the polyurethane foam is 120 μm, the pore density is 160 PPI, the porosity is 80%-95%, the average pore diameter is about 270 μm, the maximum pore diameter is about 470 μm. The proportion of the number of pores with pore diameters between 0.5 times the average pore diameter D avg and 1.5 times the average pore diameter D avg is about 81.3%, the proportion of the number of pores with pore diameters less than 0.5 times the average pore diameter D avg is about 10.3%, and the proportion of the number of pores with pore diameters greater than 1.5 times the average pore diameter D avg is about 8.4%.

[0203] Example 4

[0204] The preparation method of the metal foam matrix is similar to that of Example 1, except that the parameters of the polyurethane foam matrix are different.

[0205] The thickness of the polyurethane foam is 120 μm, the pore density is 170 PPI, the porosity is 80%-95%, the average pore diameter is about 260 μm, the maximum pore diameter is about 470 μm. The proportion of the number of pores with pore diameters between 0.5 times the average pore diameter D avg and 1.5 times the average pore diameter D avg is about 81.5%, the proportion of the number of pores with pore diameters less than 0.5 times the average pore diameter D avg is about 11.1%, and the proportion of the number of pores with pore diameters greater than 1.5 times the average pore diameter D avg is about 7.4%.

[0206] Example 5

[0207] The preparation method of the metal foam matrix is similar to that of Example 1, except that the parameters of the polyurethane foam matrix are different.

[0208] The thickness of the polyurethane foam is 120 μm, the pore density is 180 PPI, the porosity is 80% - 95%, the average pore diameter is about 250 μm, and the maximum pore diameter is about 450 μm. The proportion of the number of pores with a pore diameter between 0.5 times the average pore diameter D avg and 1.5 times the average pore diameter D avg is about 82.0%, the proportion of the number of pores with a pore diameter less than 0.5 times the average pore diameter D avg is about 11.5%, and the proportion of the number of pores with a pore diameter greater than 1.5 times the average pore diameter D avg is about 6.5%.

[0209] Example 6

[0210] The preparation method of the metal foam matrix is similar to that of Example 1, except that the parameters of the polyurethane foam matrix are different.

[0211] The thickness of the polyurethane foam is 120 μm, the pore density is 190 PPI, the porosity is 80% - 95%, the average pore diameter is about 240 μm, and the maximum pore diameter is about 430 μm. The proportion of the number of pores with a pore diameter between 0.5 times the average pore diameter D avg and 1.5 times the average pore diameter D avg is about 83.5%, the proportion of the number of pores with a pore diameter less than 0.5 times the average pore diameter D avg is about 11.9%, and the proportion of the number of pores with a pore diameter greater than 1.5 times the average pore diameter D avg is about 4.6%.

[0212] Example 7

[0213] The preparation method of the metal foam matrix is similar to that of Example 1, except that the parameters of the polyurethane foam matrix are different.

[0214] The thickness of the polyurethane foam is 120 μm, the pore density is 200 PPI, the porosity is 80% - 95%, the average pore diameter is about 230 μm, and the maximum pore diameter is about 420 μm. The proportion of the number of pores with a pore diameter between 0.5 times the average pore diameter D avg and 1.5 times the average pore diameter D avg is about 85.8%, the proportion of the number of pores with a pore diameter less than 0.5 times the average pore diameter D avg is about 11.9%, and the proportion of the number of pores with a pore diameter greater than 1.5 times the average pore diameter D avg is about 2.3%.

[0215] Example 8

[0216] The preparation method of the metal foam matrix is similar to that of Example 1, except that the parameters of the polyurethane foam matrix are different.

[0217] The thickness of the polyurethane foam is 120 μm, the pore density is 240 PPI, the porosity is 80%-95%, the average pore diameter is about 160 μm, the maximum pore diameter is about 300 μm. The proportion of the number of pores with pore diameters between 0.5 times the average pore diameter D avg and 1.5 times the average pore diameter D avg is about 73.2%, the proportion of the number of pores with pore diameters less than 0.5 times the average pore diameter D avg is about 12.3%, and the proportion of the number of pores with pore diameters greater than 1.5 times the average pore diameter D avg is about 14.5%.

[0218] Example 9

[0219] The preparation method of the metal foam matrix is similar to that of Example 1, except that the parameters of the polyurethane foam matrix are different.

[0220] The thickness of the polyurethane foam is 120 μm, the pore density is 250 PPI, the porosity is 80%-95%, the average pore diameter is about 140 μm, the maximum pore diameter is about 260 μm. The proportion of the number of pores with pore diameters between 0.5 times the average pore diameter D avg and 1.5 times the average pore diameter D avg is about 72.6%, the proportion of the number of pores with pore diameters less than 0.5 times the average pore diameter D avg is about 13.9%, and the proportion of the number of pores with pore diameters greater than 1.5 times the average pore diameter D avg is about 13.5%.

[0221] Example 10

[0222] The preparation method of the metal foam matrix is similar to that of Example 1, except that the parameters of the polyurethane foam matrix are different.

[0223] The thickness of the polyurethane foam is 120 μm, the pore density is 260 PPI, the porosity is 80%-95%, the average pore diameter is about 120 μm, the maximum pore diameter is about 250 μm. The proportion of the number of pores with pore diameters between 0.5 times the average pore diameter D avg and 1.5 times the average pore diameter D avg is about 72.4%, the proportion of the number of pores with pore diameters less than 0.5 times the average pore diameter D avg is about 14.7%, and the proportion of the number of pores with pore diameters greater than 1.5 times the average pore diameter D avg is about 12.9%.

[0224] Comparative Example 1

[0225] The preparation method of the metal foam matrix is similar to that of Example 1, except that the parameters of the polyurethane foam matrix are different.

[0226] The thickness of the polyurethane foam is 120 μm, the pore density is 120 PPI, the porosity is 80% - 95%, the average pore diameter is about 300 μm, and the maximum pore diameter is about 500 μm. Among the pores in the polyurethane foam, the proportion of the number of pores with a pore diameter between 0.5 times the average pore diameter D avg and 1.5 times the average pore diameter D avg is about 66.2%, the proportion of the number of pores with a pore diameter less than 0.5 times the average pore diameter D avg is about 1.9%, and the proportion of the number of pores with a pore diameter greater than 1.5 times the average pore diameter D avg is about 31.9%.

[0227] Comparative Example 2

[0228] The preparation method of the metal foam matrix is similar to that of Example 1, except that the parameters of the polyurethane foam matrix are different.

[0229] The thickness of the polyurethane foam is 120 μm, the pore density is 270 PPI, the porosity is 80% - 95%, the average pore diameter is about 100 μm, and the maximum pore diameter is about 250 μm. Among the pores in the polyurethane foam, the proportion of the number of pores with a pore diameter between 0.5 times the average pore diameter D avg and 1.5 times the average pore diameter D avg is about 70.9%, the proportion of the number of pores with a pore diameter less than 0.5 times the average pore diameter D avg is about 16.7%, and the proportion of the number of pores with a pore diameter greater than 1.5 times the average pore diameter D avg is about 12.4%.

[0230] Performance Test of Polyurethane Foam and Foamed Metal Matrix

[0231] (1) Measurement of the pore diameter, pore size distribution, and rib width dimension of the polyurethane foam and the metal foam matrix

[0232] Randomly select 10 regions on the metal foam matrix, observe the samples using an optical microscope, take photos at a magnification of 200 times, and measure and mark the pore diameter and rib width of all surface pores on the surface of the metal foam matrix. There are at least 20 surface pores in the photo corresponding to each region.

[0233] The pore diameter refers to the average diameter of the pore, and the average diameter refers to the arithmetic mean of the longest diameter and the shortest diameter of the pore.

[0234] The rib width refers to the width of the rib between pores.

[0235] Take the average value of the pore diameters of all the obtained surface pores as the average pore diameter D of the metal foam matrixavg .

[0236] Take the maximum value among the pore diameters of all the obtained surface pores as the maximum pore diameter D of the metal foam matrix max .

[0237] Take the number of all the obtained surface pores as the denominator, and take the number of pores with pore diameters between 0.5 times the average pore diameter D avg and 1.5 times the average pore diameter D avg as the numerator, and calculate the proportion of the number of pores with pore diameters between 0.5 times the average pore diameter D avg and 1.5 times the average pore diameter D avg .

[0238] Take the number of all the obtained surface pores as the denominator, and take the number of pores with pore diameters less than 0.5 times the average pore diameter D avg as the numerator, and calculate the proportion of the number of pores with pore diameters less than 0.5 times the average pore diameter D avg .

[0239] Take the number of all the obtained surface pores as the denominator, and take the number of pores with pore diameters greater than 1.5 times the average pore diameter D avg as the numerator, and calculate the proportion of the number of pores with pore diameters greater than 1.5 times the average pore diameter D avg .

[0240] Take the average value of the obtained rib wire widths as the rib wire width of the metal foam matrix

[0241] The test method for the polyurethane foam is the same as that for the metal foam matrix

[0242] (2) Pore density test of polyurethane foam and metal foam matrix

[0243] Refer to GB / T 20251-2006 for the test. Take the average number of pores on the surface with a length of one inch (i.e., 2.54 cm) as the pore density

[0244] Use an optical microscope with a magnification of 100 times to check the number of pores of the polyurethane foam and the metal foam matrix. When testing, randomly select 10 areas on the polyurethane foam and the metal foam matrix, and take the average value of the test results

[0245] (3) Porosity test of polyurethane foam and metal foam matrix

[0246] Use the kerosene displacement method to measure the porosity

[0247] The volume (or apparent volume) V0 of the metal foam matrix in the natural state = t × s. t represents the thickness of the metal foam matrix, with the unit of cm; s represents the area of the metal foam matrix, with the unit of cm 2Measurement of the thickness of the foam metal matrix: Use a micrometer with a precision of 0.01 mm to measure the thickness t of the foam metal matrix, and take the average value after measuring 10 points. Measurement of the area of the foam metal matrix: Place the coordinate paper on a flat transparent glass, place a white plane light source under the glass, then place the foam metal matrix to be measured on the coordinate paper, read the area projected by the foam metal matrix on the coordinate paper, measure the sample to be tested twice and take the average value, denoted as s. The difference between the two measurement readings should not exceed 1%.

[0248] The absolute dense volume V of the foam metal matrix is measured as follows.

[0249] Take a calibrated measuring cylinder, wash and dry it. Put the measuring cylinder, dropper, kerosene and the foam metal matrix sample to be tested into the calibration laboratory 4 hours in advance, control the temperature at 20±5°C, and the temperature change does not exceed 1°C / h. During the test, first put the foam metal matrix into the measuring cylinder, then place the measuring cylinder on the balance to tare, and then use the dropper to drop kerosene into the measuring cylinder. After the meniscus of the kerosene liquid level passes over the foam metal matrix, then drop by drop add kerosene to accurately adjust the liquid level to a certain scale of the measuring cylinder, and then read the indication V1 (unit: mL) of the measuring cylinder at this time and the weight m3 (unit: g) shown on the balance. The absolute dense volume V of the foam metal matrix = (V1×ε) – (m3 / ρ). ε is the correction coefficient of the measuring cylinder; ρ is the density of kerosene, with the unit g / cm 3 .

[0250] The porosity P of the foam metal matrix = (V0 - V) / V0×100%.

[0251] The test method of the polyurethane foam is the same as that of the foam metal matrix.

[0252] (4) Test of the electrochemically active specific surface area of the foam metal matrix

[0253] Cut the prepared foam metal matrix into small round piece samples with a diameter of 20 mm, and prepare a button cell with a lithium metal sheet as the counter electrode. The electrolyte salt of the electrolyte of the button cell is LiFSI, with a concentration of 1 mol / L. The solvent of the electrolyte uses ethylene glycol dimethyl ether (DME), and the probe molecule uses ferrocene, with a concentration of 50 mmol / L. The separator of the button cell can use a PE film with a thickness of 12 μm.

[0254] At 25°C, after the assembled button cell is left standing for 12 h, discharge it at a constant voltage of 2.5 V and wait for the current to drop to 0.0025 mA / cm 2, cyclic voltammetry scans were performed at 3 mV / s, 2 mV / s, 1 mV / s, and 0.5 mV / s in the range of 2.5 V - 3.4 V, and the peak current of the forward scan at each scan rate was read. The linear regression method was used to linearly regress the peak current and the square root of the scan rate to obtain the slope; the electrochemically active specific surface area of the foam metal matrix was calculated according to the Randles-Sevick equation. The test instrument was the Solartron electrochemical workstation from Solartron Analytical, UK.

[0255]

[0256] Next, the battery was assembled directly using the above-prepared foam metal matrix as the negative current collector, and the following performance tests were carried out.

[0257] Battery preparation: Lithium iron phosphate, conductive agent carbon black (Super P), and binder polyvinylidene fluoride (PVDF) were mixed evenly in an appropriate amount of solvent N-methylpyrrolidone (NMP) according to a weight ratio of 8:1:1 to obtain the positive electrode paste; the positive electrode paste was coated on the positive current collector aluminum foil, and after drying, the positive electrode plate was obtained. In a glove box under argon protection, the positive electrode plate and the above-prepared foam metal matrix were assembled into a button battery. The electrolyte salt of the electrolyte was LiFSI with a concentration of 1 mol / L, and the solvent of the electrolyte was ethylene glycol dimethyl ether (DME). The separator was a PE membrane with a thickness of 12 μm.

[0258] Cycling performance test: At 25 °C, after the assembled button battery was allowed to stand for 12 h, it was charged at a constant current of 0.2C to 3.65 V, and then charged at a constant voltage of 3.65 V to 0.05C; after the button battery was allowed to stand for 10 min, it was discharged at a constant current of 1C to 2 V. The button battery was charged and discharged according to the above method, and the number of cycles corresponding to when the discharge capacity decayed to 40% of the first-cycle discharge capacity was recorded. During the test, the number of button battery samples could be more than 6, and the test results were averaged.

[0259] Rate performance test: At 25 °C, after the assembled button battery was allowed to stand for 12 h, it was charged at a constant current of 1C and 0.2C to 3.65 V to obtain the 1C charge capacity and the 0.2C charge capacity respectively. The rate performance of the button battery was characterized by the ratio of the 1C charge capacity to the 0.2C charge capacity. The closer this value is to 1, the better the rate performance of the button battery. During the test, the number of button battery samples could be more than 6, and the test results were averaged.

[0260] Table 2

[0261] Serial Number Number of Cycles (cycles) 1C Charge Capacity / 0.2C Charge Capacity Comparative Example 1 20 91.20％ Comparative Example 2 36 98.40％ Example 1 44 92.10％ Example 2 48 93.50％ Example 3 56 94.10％ Example 4 53 94.20％ Example 5 54 95.20％ Example 6 51 95.80％ Example 7 56 96.20％ Example 8 57 96.60％ Example 9 53 97.10％ Example 10 45 98.30％

[0262] From the test results in Table 1 and Table 2, it can be seen that by adjusting the electrochemically active mass specific surface area of the foam metal matrix to 2.5 cm2 / g - 20 cm 2 / g, the electrochemically active volume specific surface area is 22 cm 2 / cm 3 -180 cm 2 / cm 3 , which can endow the battery with both long cycle life and high rate charge capacity retention rate.

[0263] The electrochemically active specific surface area of the foam metal matrix prepared in Comparative Example 1 is too small, and the pore size distribution of the foam metal matrix is uneven, which will result in uneven surface current density distribution on the negative electrode, and further lead to poor cycle performance and high rate charge capacity retention rate of the battery.

[0264] The electrochemically active specific surface area of the foam metal matrix prepared in Comparative Example 2 is too large. At this time, the content of small pores in the foam metal matrix is large. When the battery is charged, the pores on the negative electrode side close to the separator will be quickly blocked by the deposited metal, and it is difficult or even impossible for the ions in the electrolyte to supplement to the inner position of the negative electrode. As a result, the space utilization rate of the negative electrode is reduced, and at the same time, the wettability of the electrolyte of the negative electrode becomes poor, which further leads to poor cycle performance of the battery.

[0265] Next, the first cycle Coulombic efficiency of the battery was also tested. At 25 °C, after the assembled coin cell was left standing for 12 h, it was charged at a constant current of 0.1C to 3.65 V, and then charged at a constant voltage of 3.65 V to 0.05C to obtain the charge capacity; after the coin cell was left standing for 10 min, it was discharged at a constant current of 0.2C to 2 V to obtain the discharge capacity. The first cycle Coulombic efficiency = discharge capacity / charge capacity. The test results are shown in Table 3.

[0266] Table 3

[0267] Serial Number Initial Coulombic Efficiency Example 1 93.20％ Example 2 93.00％ Example 3 92.60％ Example 4 92.50％ Example 5 92.20％ Example 6 86.90％ Example 7 86.20％ Example 8 84.30％ Example 9 80.60％ Example 10 77.20％

[0268] It can be seen from the test results in Table 3 that by further adjusting the electrochemically active mass specific surface area and electrochemically active volume specific surface area of the foam metal matrix, the battery can have a high Coulombic efficiency on the premise of having good cycle performance and rate performance. This is because when the electrochemically active specific surface area of the foam metal matrix increases, more active ions are consumed to activate the deposition sites on the negative electrode surface during the first charge of the battery, which will reduce the first cycle Coulombic efficiency of the battery.

[0269] It should be noted that this application is not limited to the above-mentioned embodiments. The above-mentioned embodiments are only examples, and embodiments having the same composition and the same function and effect as the technical idea within the scope of the technical solution of this application are all included in the technical scope of this application. In addition, within the scope of not departing from the gist of this application, various modifications that can be conceived by those skilled in the art to the embodiments, and other ways constructed by combining some of the constituent elements in the embodiments are also included in the scope of this application.

Claims

1. A negative electrode current collector, characterized in that, The negative current collector includes a porous metal matrix, and the electrochemically active mass specific surface area of the porous metal matrix is 2.5 cm 2 / g - 20 cm 2 / g, and the electrochemically active volume specific surface area is 22 cm 2 / cm 3 - 180 cm 2 / cm 3 。 2. The negative electrode current collector according to claim 1, wherein The electrochemically active mass specific surface area of the foamed metal matrix is 3.2 cm 2 / g - 10 cm 2 / g, and the electrochemically active volume specific surface area is 29 cm 2 / cm 3 - 90 cm 2 / cm 3 .

3. The negative electrode current collector according to claim 2, wherein, The electrochemically active mass specific surface area of the foamed metal matrix is 3.2 cm 2 / g - 5 cm 2 / g, and the electrochemically active volume specific surface area is 29 cm 2 / cm 3 - 45 cm 2 / cm 3 .

4. The negative electrode current collector according to any one of claims 1-3, characterized in that The number of pores in the porous metal matrix with pore diameters between 0.5 times the average pore diameter D avg and 1.5 times the average pore diameter D avg is 80%-90% of the total number of pores in the porous metal matrix; and / or, The number of pores with a pore diameter less than 0.5 times the average pore diameter D in the metal foam matrix is 4.5% - 12% of the total number of pores in the metal foam matrix; and / or, avg the number of pores with a pore diameter less than 0.5 times the average pore diameter D in the metal foam matrix is 4.5% - 12% of the total number of pores in the metal foam matrix; and / or, The pore diameter in the porous metal matrix is greater than 1.5 times the average pore diameter D avg The number of pores is 2%-12% of the total number of pores in the porous metal matrix.

5. The negative electrode current collector according to any one of claims 1-4, characterized in that The average pore diameter D of the metallic foam matrix avg is 120 μm - 290 μm; and / or, The maximum pore diameter D of the metallic foam matrix max is 200 μm - 500 μm.

6. The negative electrode current collector according to any one of claims 1-5, characterized in that, the rib width of the foam metal matrix is 5 μm - 100 μm.

7. The negative electrode current collector according to any one of claims 1-6, characterized in that, the pore density of the foam metal matrix is 135 PPI - 200 PPI.

8. The negative electrode current collector according to any one of claims 1-7, characterized in that, the porosity of the foam metal matrix is 65% - 91%.

9. The negative electrode current collector according to any one of claims 1-8, characterized in that, the foam metal matrix is an open-cell structure, and the open-cell rate is greater than or equal to 98%.

10. The negative electrode current collector according to any one of claims 1-9, characterized in that, the thickness of the foam metal matrix is 80 μm - 1000 μm.

11. The negative electrode current collector according to any one of claims 1-10, characterized in that, the metal elements in the foam metal matrix include one or more of copper, nickel, titanium, aluminum, cobalt, iron, manganese, tin, gold, silver, chromium, zinc, cadmium, lead, platinum, antimony, bismuth, gallium, indium, palladium.

12. The negative electrode current collector according to any one of claims 1-11, characterized in that, the negative electrode current collector further includes an alkali metal affinity layer located on the surface of the foam metal matrix.

13. The negative electrode current collector according to claim 12, characterized in that the alkali metal affinity layer includes one or more of Cu2O, Li3N; and / or the thickness of the alkali metal affinity layer is 50 nm - 5 μm.

14. A battery cell, characterized in that, including the negative electrode current collector according to any one of claims 1-13.

15. The battery cell according to claim 14, characterized in that, the battery cell includes at least one of a lithium metal battery cell without a negative electrode and a sodium metal battery cell without a negative electrode.

16. A battery, characterized in that, including the battery cell according to any one of claims 14-15.

17. An electrical device, characterized in that, including the battery according to claim 16, and the battery is used to provide electrical energy.

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