Battery, battery assembly and electric equipment

Abstract

The utility model discloses a battery, a battery assembly and electric equipment, the battery comprises at least one subunit, the subunit comprises a first lithium supplement electrode and a current collector unit, and a plurality of holes are formed in the current collector unit; in the subunits, the current collector unit meets the condition that the apertures of the plurality of holes are in an increasing trend in the direction far away from the first lithium supplementing electrode; and / or in the direction far away from the first lithium supplementing electrode, the porosity tends to be increased; and / or the current collector unit comprises a first current collector and a second current collector, the second current collector is arranged on the side, away from the first lithium supplementing electrode, of the first current collector, and the thickness of the second current collector is smaller than that of the first current collector. According to the battery disclosed by the utility model, the lithium supplementing electrode is adopted to uniformly supplement lithium to the current collector unit, so that the battery has high coulombic efficiency when being charged and discharged for the first time, and the cycle characteristic of the battery is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of batteries, in particular to a battery, a battery assembly and an electrical device. Background Art

[0002] In the related technology, by replenishing lithium to the electrode material and replenishing the lithium ions consumed in the electrode material, the irreversible lithium loss caused by the formation of the SEI film can be offset, the first coulombic efficiency of the battery cell can be improved, and thus the total capacity and energy density of the battery can be improved.

[0003] In the related art, a three-electrode battery is used in which a lithium replenishing electrode is inserted between the positive and negative electrodes to replenish lithium at the negative electrode or the positive electrode. However, this lithium replenishing method has the problem of uneven lithium replenishing concentration, which is likely to cause safety hazards or performance defects. Utility Model Content

[0004] The utility model aims to solve at least one of the technical problems existing in the prior art. To this end, one purpose of the utility model is to provide a battery that can evenly replenish lithium and has good safety performance.

[0005] Another object of the present invention is to provide a battery assembly.

[0006] Another object of the present invention is to provide an electrical device.

[0007] According to the battery of the embodiment of the first aspect of the utility model, the subunit includes at least one subunit, the subunit includes a first lithium supplement electrode and a current collector unit, and a plurality of holes are formed on the current collector unit; in the subunit, the current collector unit satisfies: the pore diameters of the plurality of holes tend to increase in the direction away from the first lithium supplement electrode; and / or the porosity tends to increase in the direction away from the first lithium supplement electrode; and / or the current collector unit includes a first current collector and a second current collector, the second current collector is arranged on a side of the first current collector away from the first lithium supplement electrode, and the thickness of the second current collector is less than the thickness of the first current collector.

[0008] According to a specific embodiment of the utility model, the battery includes a first lithium replenishing electrode and a current collector unit. During the charge and discharge process, the first lithium replenishing electrode can be used to replenish lithium for the current collector unit. Combined with the diffusion law of lithium ions during the lithium replenishment process (the farther away from the first lithium replenishing electrode, the slower the diffusion speed of lithium ions), a suitable lithium ion diffusion channel is set to reduce the resistance of lithium ion diffusion in the current collector unit away from the first lithium replenishing electrode, so as to improve the diffusion uniformity of lithium ions in the current collector unit. In this way, it is achieved that during the first charge and discharge and cycle process, the metal lithium is driven by both the potential difference and the lithium ion concentration difference, and the lithium ions are uniformly diffused into the entire battery through the through hole. Specifically, it can be set that the pore size of the plurality of holes tends to increase along the direction away from the first lithium replenishing electrode; and / or the porosity tends to increase; and / or the current collector unit includes a first current collector and a second current collector, the second current collector is arranged on the side of the first current collector away from the first lithium replenishing electrode, and the thickness of the second current collector is less than the thickness of the first current collector. In this way, the uniform diffusion of lithium ions is promoted, and lithium elements are controllably supplemented to the negative electrode and / or positive electrode during the first charge or cycle process, so as to achieve high coulombic efficiency during the first charge and discharge of the battery and improve the cycle characteristics of the battery.

[0009] According to some embodiments of the utility model, in the subunit, the current collector unit includes a first current collector and a second current collector, and the second current collector is arranged on a side of the first current collector away from the first lithium supplement electrode; the current collector unit satisfies: the average pore size of the second current collector is greater than the average pore size of the first current collector; and / or the porosity of the second current collector is greater than the porosity of the first current collector.

[0010] According to some embodiments of the present invention, the battery includes a plurality of the sub-units, and the plurality of the sub-units are stacked.

[0011] According to some embodiments of the present invention, the first lithium-replenishing electrode, the separator, the first electrode, the separator, the second electrode, the separator, the third electrode, the separator, the fourth electrode, the separator and the first lithium-replenishing electrode are stacked in sequence, the first electrode includes the first current collector, the second electrode includes the second current collector, the third electrode includes the second current collector, and the fourth electrode includes the first current collector.

[0012] According to some embodiments of the present invention, at least one of the first current collector and the second current collector is a porous metal foil.

[0013] According to some embodiments of the present invention, the pore diameter of the pore is d1, wherein the d1 satisfies: 1μm≤d1≤1000μm; and / or the porosity is a1, wherein the a1 satisfies: 1%≤a1≤90%; and / or the thickness of at least one of the first current collector and the second current collector is h1, wherein the h1 satisfies: 1μm≤h1≤20μm.

[0014] According to some embodiments of the present invention, the d1 satisfies: 2μm≤d1≤500μm; and / or the a1 satisfies: 10%≤a1≤60%; and / or the h1 satisfies: 2μm≤h1≤8μm.

[0015] According to some embodiments of the present invention, the d1 satisfies: 3μm≤d1≤50μm; and / or the a1 satisfies: 30%≤a1≤40%.

[0016] According to some embodiments of the present invention, the first lithium-supplementing electrode includes a lithium-supplementing layer, and the lithium-supplementing layer includes at least one of a lithium layer, a lithium-silicon alloy layer, a lithium-aluminum alloy layer, a lithium-boron alloy layer, and a lithium-magnesium alloy layer.

[0017] According to some embodiments of the present invention, the thickness of the lithium replenishing layer is h2, wherein h2 satisfies: 20 μm≤h2≤1 mm.

[0018] According to some embodiments of the present invention, h2 satisfies: 20 μm≤h2≤700 μm.

[0019] According to some embodiments of the present invention, the first lithium-supplementing electrode further includes: a lithium-supplementing current collector, and the lithium-supplementing layer is disposed on the lithium-supplementing current collector.

[0020] The battery assembly according to the embodiment of the second aspect of the utility model includes the battery according to the embodiment of the first aspect of the utility model.

[0021] The electrical equipment according to the third aspect of the present invention comprises the battery according to the first aspect of the present invention, or comprises the battery assembly according to the second aspect of the present invention.

[0022] Additional aspects and advantages of the present invention will be given in part in the following description, and in part will become apparent from the following description, or will be learned through the practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0024] Figure 1This is a schematic diagram of a battery structure according to an embodiment of the utility model;

[0025] Figure 2 is a schematic diagram of a battery structure according to another embodiment of the utility model;

[0026] Figure 3 is a schematic diagram of a battery structure according to another embodiment of the utility model;

[0027] Figure 4 This is a schematic diagram of the positive electrode structure according to an embodiment of the utility model;

[0028] Figure 5 It is a schematic diagram of the negative electrode structure according to an embodiment of the utility model.

[0029] Reference numerals:

[0030] 100: battery;

[0031] 1: The first lithium supplement electrode;

[0032] 2: positive electrode; 21: positive electrode current collector; 22: positive electrode dressing layer;

[0033] 3: negative electrode; 31: negative electrode current collector; 32: negative electrode dressing layer;

[0034] 4: diaphragm;

[0035] 5: Shell

[0036] 6: Subunit. DETAILED DESCRIPTION

[0037] The embodiments of the present invention are described in detail below. The embodiments described with reference to the accompanying drawings are exemplary. Figure 1-5 The battery 100 according to the first embodiment of the utility model includes at least one subunit, the subunit includes a first lithium supplement electrode 1 and a current collector unit, and a plurality of holes are formed on the current collector unit. In one subunit, the current collector unit satisfies at least one of the following (1) to (3):

[0038] (1) In the direction away from the first lithium supplement electrode 1, the pore diameters of the plurality of pores tend to increase;

[0039] (2) The porosity tends to increase in the direction away from the first lithium supplement electrode 1;

[0040] (3) The current collector unit includes a first current collector and a second current collector. The second current collector is disposed on a side of the first current collector away from the first lithium supplementing electrode 1 . The thickness of the second current collector is smaller than that of the first current collector.

[0041] Among them, along the direction away from the first lithium supplement electrode 1, the pore size of the multiple holes tends to increase. This tendency of increasing pore size of the multiple holes can be reflected on the same current collector. For example, the current collector unit includes a first current collector, and the first current collector is divided into multiple sublayers along the direction away from the first lithium supplement electrode 1. Along the direction away from the first lithium supplement electrode 1, the average pore size of the multiple holes in different sublayers tends to increase; or, the current collector unit includes a first current collector and a second current collector. When the second current collector is arranged on the side of the first current collector away from the first lithium supplement electrode 1, the average pore size of the multiple holes in the second current collector is greater than the average pore size of the multiple holes in the first current collector. In this arrangement, the larger the pore size, the smaller the resistance of the pore to the diffusion of lithium ions. In the process of lithium supplementation, the lithium ions on the first lithium supplement electrode 1 diffuse from the first lithium supplement electrode 1 to the direction away from the first lithium supplement electrode 1. The farther away from the first lithium supplement electrode 1, the greater the energy loss, and the slower the diffusion speed. In this way, the diffusion rate of lithium ions is increased by reducing the resistance of the pores, and the uniform diffusion of lithium ions in the current collector unit is promoted, thereby achieving uniform lithium replenishment of the current collector unit. Specifically, the trend of increasing pore size may include the following: first, the pore size continues to increase at a certain increase rate, second, the pore size continues to increase at an uncertain increase rate, third, the pore size increases, remains unchanged, and increases, and fourth, the pore size increases, decreases (the pore size after reduction is larger than the original pore size), and then increases again, but is not limited to this. It should be pointed out that the pores here can be round, square, or irregular in shape.

[0042] In addition, the porosity tends to increase along the direction away from the first lithium supplement electrode 1. This trend of increasing porosity can be reflected on the same current collector. For example, the current collector unit includes a first current collector, and the first current collector is divided into multiple sublayers along the direction away from the first lithium supplement electrode 1. The porosity of different sublayers tends to increase along the direction away from the first lithium supplement electrode 1; or, the current collector unit includes a first current collector and a second current collector. When the second current collector is arranged on the side of the first current collector away from the first lithium supplement electrode 1, the porosity of the second current collector is greater than the porosity of the first current collector. In this way, on the current collector unit, as the porosity increases, the volume proportion of the pores on the current collector unit increases, the total volume of the diffusion channel of lithium ions increases, and the resistance to the diffusion of lithium ions decreases, which is conducive to increasing the diffusion speed of lithium ions and promoting the uniform diffusion of lithium ions in the current collector unit. Thereby, uniform lithium supplementation of the current collector unit is achieved. Specifically, the increase in porosity can be that the pore size of a single pore remains unchanged, but the total number of pores increases; or the number of pores remains unchanged, and the pore size becomes larger. The increasing trend may include the following: first, the porosity continues to increase at a certain rate of increase; second, the porosity continues to increase at an uncertain rate of increase; third, the porosity increases, remains unchanged, and increases; fourth, the porosity increases, decreases (the pore size after reduction is larger than the original porosity), and increases again, etc., but is not limited to these.

[0043] In addition, the current collector unit includes a first current collector and a second current collector, the second current collector is arranged on the side of the first current collector away from the first lithium supplement electrode 1, and the thickness of the second current collector is less than the thickness of the first current collector. In this way, along the direction away from the first lithium supplement electrode 1, the thickness of the second current collector is less than the thickness of the first current collector, that is, the length of the diffusion path in the second current collector during the propagation of lithium ions is less than the length of the diffusion path in the first current collector. In this way, it is beneficial to reduce the resistance of lithium ions in the second current collector, increase the diffusion speed of lithium ions, and promote the uniform diffusion of lithium ions in the first current collector and the second current collector, thereby achieving uniform lithium supplementation of the first current collector and the second current collector.

[0044] According to the battery 100 of the specific embodiment of the utility model, it includes a first lithium supplement electrode 1 and a current collector unit. During the charge and discharge process, the first lithium supplement electrode 1 is used to supplement the current collector unit with lithium. In combination with the diffusion law of lithium ions during the lithium supplement process (the farther away from the first lithium supplement electrode 1, the slower the diffusion of lithium ions), a suitable lithium ion diffusion channel is set, so that the resistance to the diffusion of lithium ions in the current collector unit along the direction away from the first lithium supplement electrode 1 tends to decrease, so that lithium ions can be evenly diffused in the current collector unit. In this way, it is achieved that during the first charge and discharge and cycle process, the metal lithium is driven by both the potential difference and the lithium ion concentration difference, and the lithium ions are evenly diffused into the entire battery 100 through the through hole. Specifically, it can be set that the pore size of multiple holes tends to increase in the direction away from the first lithium supplement electrode 1; and / or the porosity tends to increase; and / or the current collector unit includes a first current collector and a second current collector, the second current collector is arranged on the side of the first current collector away from the first lithium supplement electrode 1, and the thickness of the second current collector is less than the thickness of the first current collector. In this way, the uniform diffusion of lithium ions is promoted, and lithium elements are controllably supplemented to the negative electrode 3 and / or the positive electrode 2 during the first or cycle process, so as to achieve high coulombic efficiency during the first charge and discharge of the battery 100 and improve the cycle characteristics of the battery 100.

[0045] According to some embodiments of the utility model, the current collector unit includes a first current collector and a second current collector, the second current collector is arranged on a side of the first current collector away from the lithium supplement electrode, and the average pore size of the second current collector is larger than the average pore size of the first current collector. In this way, when the average pore size of the second current collector is larger than the average pore size of the first current collector, during the diffusion and replenishment of lithium by the first lithium supplement electrode 1, the resistance in the second current collector is smaller than the resistance in the first current collector, which is conducive to increasing the diffusion speed of lithium ions in the second current collector, promoting the uniform diffusion of lithium ions in the first current collector and the second current collector, thereby achieving uniform lithium supplementation of the first current collector and the second current collector.

[0046] According to some other embodiments of the utility model, the current collector unit includes a first current collector and a second current collector, the second current collector is arranged on the side of the first current collector away from the lithium replenishing electrode, and the porosity of the second current collector is greater than the porosity of the first current collector. In this way, when the porosity of the second current collector is greater than the porosity of the first current collector, the volume proportion of the pores on the second current collector increases, the total volume of the diffusion channel of lithium ions on the second current collector increases, and the resistance to the diffusion of lithium ions becomes smaller, which is conducive to increasing the diffusion speed of lithium ions and promoting the uniform diffusion of lithium ions in the first current collector and the second current collector. Thereby achieving uniform lithium replenishment of the first current collector and the second current collector.

[0047] According to some embodiments of the present invention, the battery 100 includes one or more subunits 6. When the battery 100 includes multiple subunits 6, the multiple subunits 6 are stacked, and each subunit 6 includes a lithium supplement electrode 1 and a current collector unit.

[0048] In this configuration, each subunit 6 includes a lithium supplement electrode 1 and a current collector unit, and the current collector unit may include one or more. When a subunit 6 includes multiple current collector units, the multiple current collector units may be arranged on the same side or on opposite sides of the lithium supplement electrode 1. In the direction away from the lithium supplement electrode 1, one or more current collector units are arranged according to the above rule.

[0049] According to some embodiments of the utility model, the battery 100 includes a first lithium supplement electrode 1, a separator 4, a first electrode, a separator 4, a second electrode, a separator 4, a third electrode, a separator 4, a fourth electrode, a separator 4 and a first lithium supplement electrode 1 stacked in sequence. Among them, the first electrode includes a first current collector, the second electrode includes a second current collector, the third electrode includes a second current collector, and the fourth electrode includes a first current collector. In this way, two first lithium supplement electrodes 1 are used to uniformly supplement lithium for the first electrode, the second electrode, the third electrode and the fourth electrode. Among them, the battery 100 may also include a fifth electrode, a sixth electrode, etc., but is not limited thereto.

[0050] According to some embodiments of the present invention, the current collector unit includes a first current collector and a second current collector, the first current collector is one of the positive electrode current collector 21 and the negative electrode current collector 31, and the second current collector is the other of the positive electrode current collector 21 and the negative electrode current collector 31. Among them, the positive electrode 2 includes the positive electrode current collector 21, and the negative electrode 3 includes the negative electrode current collector 31. That is, the battery 100 includes a first lithium supplement electrode 1 and alternating positive electrodes 2 and negative electrodes 3.

[0051] For example, the battery 100 may include a positive electrode 2, a separator 4, a negative electrode 3, a separator 4, an electrolyte, a first lithium replenishing electrode 1, and a shell 5, and are sequentially arranged in the order of first lithium replenishing electrode 1 | separator 4 | positive electrode 2 | separator 4 | negative electrode 3 | separator 4 | positive electrode 2 | separator 4 | first lithium replenishing electrode 1 to form a stack or winding (positive electrode 2, separator 4, negative electrode 3, separator 4, positive electrode 2 are repeatable units), and the first lithium replenishing electrode 1 is used as a third electrode to lead out a pole ear, and a lithium ion battery 100 having a third electrode (lithium replenishing electrode) in addition to the positive electrode 2 and the negative electrode 3 is made, wherein at least one of the positive electrode 2 and the negative electrode 3 is connected to the first lithium replenishing electrode 1.

[0052] Further, for example, Figure 1As shown, the battery 100 includes two subunits 6, each subunit 6 includes a lithium supplement electrode 1, a first current collector and a second current collector, and the second current collector is arranged on the side of the first current collector away from the first lithium supplement electrode 1. Along the direction away from the first lithium supplement electrode 1, the average pore size of the second current collector is greater than the average pore size of the first current collector, and the porosity and the thickness of the current collector remain unchanged. In one of the subunits 6, the first current collector close to the first lithium supplement electrode 1 is the positive electrode current collector 21, and the second current collector away from the first lithium supplement electrode 1 is the negative electrode current collector 31. Since the positive electrode 2 is close to the first lithium supplement electrode 1 and the interval between it and the first lithium supplement electrode 1 is small, it is easier to obtain lithium ions from the first lithium supplement electrode 1. However, since the negative electrode 3 is far from the first lithium supplement electrode 1 and the interval between it and the first lithium supplement electrode 1 is relatively large, the process of lithium ion transmission requires a certain amount of time and there will be a lot of loss, so it is not easy to obtain sufficient lithium ions. In this way, the larger the pore size of the second current collector is set, the smaller the resistance during the lithium ion transmission process. It is convenient for the lithium on the first lithium supplement electrode 1 to be transmitted to the positive and negative electrodes 3 where the second current collector is located. Therefore, by enlarging the size of the through hole away from the first lithium supplement electrode 1, lithium ion transmission is facilitated so that the electrodes 3 at different distances from the first lithium supplement electrode 1 in the battery 100 can be uniformly supplemented with lithium. The first current collector close to the first lithium supplement electrode 1 in another subunit 6 is the negative current collector 31, and the second current collector away from the first lithium supplement electrode 1 is the positive current collector 21. According to the distance from the first lithium supplement electrode 1, the average pore size of the positive current collector 21 is greater than the average pore size of the negative current collector 31.

[0053] For example, Figure 2As shown, the battery 100 includes two subunits 6, wherein one subunit 6 includes a first lithium supplement electrode 1, a first current collector, a second current collector, and a third current collector, and the first current collector (positive electrode 2 current collector), the second current collector (negative electrode 3 current collector), and the third current collector (positive electrode 2 current collector) are stacked on one side of the first lithium supplement electrode 1 in a direction away from the first lithium supplement electrode 1. The other subunit 6 includes a first lithium supplement electrode 1, a first current collector, a second current collector, a third current collector, and a fourth current collector, and the first current collector (positive electrode 2 current collector), the second current collector (negative electrode 3 current collector), the third current collector (positive electrode 2 current collector), and the fourth current collector (negative electrode 3 current collector) are stacked on one side of the first lithium supplement electrode 1 in a direction away from the first lithium supplement electrode 1. In each subunit 6, along the direction away from the first lithium supplement electrode 1, the porosity of the electrode collector (including the positive electrode 2 collector and the negative electrode 3 collector) increases, and the channels for lithium ion transmission increase, making it easier for lithium ions to be transmitted in the direction away from the first lithium supplement electrode 1, promoting the controllable and uniform diffusion of lithium ions, and controlling the lithium element to supplement the negative electrode 3 or the positive electrode 2 during the first or cycle process, so as to achieve a high coulomb efficiency when the battery 100 is charged for the first time, and improve the cycle characteristics of the battery 100. The positive electrode 2 or the negative electrode 3 close to the first lithium supplement electrode 1 is closer to the first lithium supplement electrode 1 and has a smaller gap with the first lithium supplement electrode 1, so it is easier to obtain lithium ions from the first lithium supplement electrode 1. However, the positive electrode 2 or the negative electrode 3 far away from the first lithium supplement electrode 1 is farther away from the first lithium supplement electrode 1 and has a larger gap with the first lithium supplement electrode 1. The process of lithium ion transmission takes a certain amount of time and there will be a large amount of loss, so it is not easy to obtain sufficient lithium ions. Therefore, by increasing the porosity of the electrode, lithium ion transport is facilitated so that the positive electrode 2 and / or the negative electrode 3 at different distances from the first lithium replenishing electrode 1 in the battery 100 can be replenished with lithium uniformly.

[0054] For example, Figure 3As shown, the battery 100 includes two subunits 6, one of which includes a first lithium supplement electrode 1, a first current collector, a second current collector and a third current collector, and the first current collector (positive electrode 2 current collector), the second current collector (negative electrode 3 current collector) and the third current collector (positive electrode 2 current collector) are stacked on one side of the first lithium supplement electrode 1 in a direction away from the first lithium supplement electrode 1. The other subunit 6 includes a first lithium supplement electrode 1, a first current collector, a second current collector, a third current collector and a fourth current collector, and the first current collector (positive electrode 2), the second current collector (negative electrode 3 current collector), the third current collector (positive electrode 2 current collector) and the fourth current collector (negative electrode 3 current collector) are stacked on one side of the first lithium supplement electrode 1 in a direction away from the first lithium supplement electrode 1. In each subunit 6, the thickness of the electrode (including the positive electrode 2 and the negative electrode 3) decreases along the direction away from the first lithium supplement electrode 1, and the pore size and porosity of the multiple electrodes of the battery 100 remain unchanged. This can promote the controllable and uniform diffusion of lithium ions, and controllably supplement lithium elements to the negative electrode 3 or the positive electrode 2 during the first charge or cycle, so as to achieve high coulombic efficiency during the first charge and discharge of the battery 100 and improve the cycle characteristics of the battery 100.

[0055] According to some embodiments of the present invention, at least one of the positive electrode current collector 21 and the negative electrode current collector 31 is a porous metal foil. The porous metal foil is convenient to process and use, and is suitable for the positive electrode current collector 21 and the negative electrode current collector 31.

[0056] According to some embodiments of the present invention, Figure 4 As shown, the positive electrode 2 also includes a positive electrode dressing layer 22, which is arranged on the surface of the positive electrode collector 21, and the positive electrode active material in the positive electrode dressing layer 22 is any one of lithium cobalt oxide, lithium manganese oxide, lithium nickel cobalt manganese oxide, lithium nickel cobalt aluminum oxide, lithium-rich layered oxide, lithium nickel manganese oxide, lithium iron phosphate, lithium manganese phosphate, lithium cobalt phosphate, lithium nickel phosphate, lithium iron manganese phosphate, iron phosphate, manganese phosphate, cobalt phosphate, nickel phosphate, lithium iron silicate, lithium manganese silicate, lithium cobalt silicate, lithium nickel silicate, iron silicate, manganese silicate, cobalt silicate, and nickel silicate.

[0057] According to some embodiments of the present invention, Figure 5 As shown, the negative electrode 3 also includes a negative electrode dressing layer 32, which is arranged on the surface of the negative electrode collector 31, and the negative electrode active material in the negative electrode dressing layer 32 is any one of natural graphite, artificial graphite, soft carbon, hard carbon, materials containing silicon, tin, germanium, zinc, aluminum, boron, magnesium elements, transition metal oxides, transition metal sulfides, transition metal fluorides, transition metal nitrides, and transition metal phosphides.

[0058] According to some embodiments of the present invention, the transition metal can be selected from one of chromium, copper, iron, cobalt, nickel, cadmium, vanadium, molybdenum, tungsten and ruthenium; according to some embodiments of the present invention, the negative electrode active material is a silicon-carbon material.

[0059] According to some embodiments of the present invention, at least one of the positive electrode current collector 21 and the negative electrode current collector 31 is a porous metal foil. In this way, the porous metal foil has good mechanical properties, a stable structure, and is not easy to deform. Optionally, the porous metal foil is one of a porous copper foil, an aluminum foil, a nickel foil, a steel foil, and a carbon film.

[0060] According to some embodiments of the utility model, the pore size is d1, wherein d1 satisfies: 1μm≤d1≤1000μm. In this way, if d1 is less than 1μm, the pore size is small, the pore is small, the current collector is difficult to prepare, and it is not conducive to the transmission of lithium ions through the through hole to the positive electrode 2 or the negative electrode 3 for lithium replenishment; if d1 is greater than 1000μm, the pore size is large, the pore is large, and the pore may reduce the pore density and increase the length of the lithium ion propagation path. At the same time, the slurry is easy to leak when it is coated on the current collector, which may affect the performance of the battery 100. By setting, d1 satisfies 1μm≤d1≤1000μm, so that the pores can meet the transmission needs of lithium ions and the structure of the battery 100 is stable.

[0061] According to some embodiments of the utility model, the porosity is a1, wherein a1 satisfies: 1%≤a1≤90%. In this way, if a1 is less than 1%, the porosity of at least one of the positive current collector 21 and the negative current collector 31 or the porosity of the current collector unit is small, and the density of the through holes on the positive current collector 21 and / or the negative current collector 31 or the through holes of the current collector unit is small, which will affect the length of the lithium ion propagation path and is not conducive to the lithium ions being transmitted to the positive electrode 2 or the negative electrode 3 through the through holes for lithium supplementation; if a1 is greater than 90%, the porosity of at least one of the positive current collector 21 and the negative current collector 31 or the porosity of the current collector unit is large, and the density of the through holes on the positive current collector 21 and the negative current collector 31 or the through holes of the current collector unit is large, which will affect the strength of the current collector and be inconvenient to process. By setting, a1 satisfies 1%≤a1≤90%, so that the porosity of at least one of the positive current collector 21 and the negative current collector 31 or the porosity of the current collector unit can meet the transmission requirements of lithium ions and the positive current collector 21 and the negative current collector 31 have high structural strength and are easy to process.

[0062] According to some embodiments of the utility model, the thickness of the positive current collector 21 and / or the negative current collector 31 is h1, wherein h1 satisfies: 1μm≤h1≤20μm. In this way, if h1 is less than 1μm, the thickness of the positive current collector 21 and / or the negative current collector 31 is small, and the structural stability of the electrode is poor, which may affect the performance of the battery 100. If h1 is greater than 20μm, the thickness of the positive current collector 21 and / or the negative current collector 31 is large, which is not conducive to the transmission of lithium ions through the through hole to the positive electrode 2 and / or the negative electrode 3 for lithium replenishment. By setting, h1 satisfies 1μm≤h1≤20μm, so that the thickness of the positive current collector 21 and / or the negative current collector 31 can meet the transmission needs of lithium ions and the structure of the battery 100 is stable.

[0063] According to some embodiments of the present invention, d1 further satisfies: 2μm≤d1≤500μm; and further satisfies: 3μm≤d1≤50μm. With such a configuration, the maximum cross-sectional diameter of the through hole is more suitable, which can better meet the transmission requirements of lithium ions, and the structure of the battery 100 is more stable.

[0064] According to some embodiments of the present invention, a1 further satisfies: 10%≤a1≤60%; and further satisfies: 30%≤a1≤40%. In this way, the porosity of at least one of the positive current collector 21 and the negative current collector 31 is more suitable, which can better meet the transmission requirements of lithium ions, and the positive current collector 21 and the negative current collector 31 have high structural strength and are easy to process.

[0065] According to some embodiments of the present invention, h1 further satisfies: 2 μm≤h1≤8 μm. In this way, the thickness of the positive electrode current collector 21 and / or the negative electrode current collector 31 is more suitable, which can better meet the transmission requirements of lithium ions, and the structure of the battery 100 is more stable.

[0066] According to some embodiments of the present invention, the first lithium supplement electrode 1 includes a lithium supplement layer. In this way, the lithium supplement layer provides lithium ions to supplement the lithium element consumed by the negative electrode 3 or the positive electrode 2 during the first or cycle process, so as to achieve high coulombic efficiency and improve cycle characteristics.

[0067] According to some embodiments of the present invention, the lithium supplement layer is at least one of a lithium layer, a lithium silicon alloy layer, a lithium aluminum alloy layer, a lithium boron alloy layer, and a lithium magnesium alloy layer. In this way, the material source of the lithium supplement layer is wide. In addition, if the lithium supplement layer has sufficient mechanical strength, the current collector can be omitted in the first lithium supplement electrode 1.

[0068] According to some embodiments of the utility model, the thickness of the lithium replenishing layer is h2, wherein h2 satisfies: 20μm≤h2≤1mm. In this way, if h2 is less than 20μm, the thickness of the lithium replenishing layer is small, the lithium source of the lithium replenishing layer is small, which is not conducive to providing a recombined lithium source, and the strength of the lithium replenishing layer is poor, the processability is poor, and it is not convenient to process; if h2 is greater than 1mm, the thickness of the lithium replenishing layer is large, which may cause the battery 100 to be thicker. By setting, h2 satisfies: 20μm≤h2≤1mm, the thickness of the lithium replenishing layer is appropriate, the structural strength is high, it is convenient to process, and the formed battery 100 has a simple structure.

[0069] According to some embodiments of the present invention, h2 further satisfies: 20 μm ≤ h2 ≤ 700 μm. In this way, the thickness of the lithium supplement layer is more suitable, the structural strength is high, and the processing is convenient. In addition, the battery 100 has a simple structure.

[0070] According to some embodiments of the utility model, the first lithium supplement electrode 1 further includes: a lithium supplement current collector, and the lithium supplement layer is arranged on the lithium supplement current collector. Such an arrangement can improve the strength of the proportional electrode and enhance its processability. Optionally, the lithium supplement layer can be in the form of a belt, a strip, a ring or a dot, formed on the current collector.

[0071] The battery assembly according to the embodiment of the second aspect of the utility model includes the battery 100 according to the embodiment of the first aspect of the utility model.

[0072] The battery assembly according to the specific embodiment of the present invention has high coulombic efficiency and excellent cycle characteristics. The battery assembly can be a battery module or a battery pack.

[0073] The electrical equipment according to the third aspect of the present invention includes the battery according to the first aspect of the present invention, or includes the battery assembly according to the second aspect of the present invention. The electrical equipment here may include vehicles, ships, 3C products, energy storage systems, etc.

[0074] The electrical equipment according to the specific embodiment of the utility model has good power supply performance, is energy-saving and environmentally friendly, and avoids frequent replacement of power supplies.

[0075] Performance test experiment

[0076] The present invention is further described in detail below by taking several specific experiments as examples and combining with the accompanying drawings.

[0077] This embodiment only cites a laminated soft-package battery, but it is also applicable to a wound battery, and also to batteries with other shells 5 and structures, such as a square steel shell and a cylindrical battery.

[0078] Example 1

[0079] 1. Prepare the positive electrode: weigh 1 kg of positive electrode active material (LiCoO2), 20 g of conductive agent Super-P, and 20 g of binder polyvinylidene fluoride (PVDF) and add them to 1 kg of N-methylpyrrolidone, then stir in a blender for 30 min to form a uniform and stable slurry; evenly coat the slurry on porous aluminum foil with a porosity of 50% and an average pore size of 20 μm and 10 μm, respectively, and name the coated porous aluminum foil the first positive electrode and the second positive electrode, respectively, and transfer the first positive electrode and the second positive electrode to an oven for drying at 80°C; after drying, press under a pressure of 2 MPa, cut into 50 mm × 75 mm, spot weld the positive electrode ears, and the surface density is 30 mg / cm 2 ;

[0080] 2. Prepare the diaphragm: Take a common commercial 11 μm polyvinylidene fluoride (PVDF) coated lithium battery polyethylene (PE) diaphragm and cut the diaphragm into 77 mm width;

[0081] 3. Prepare the negative electrode: weigh 1 kg of negative electrode active material (artificial graphite and silicon oxide composite negative electrode material with D50 of 15 μm), 10 g of conductive agent acetylene black, 30 g of binder styrene butadiene rubber and 20 g of sodium carboxymethyl cellulose, add them into 1 kg of deionized water, and then stir in a blender to form a uniform and stable slurry; evenly coat the slurry on a porous copper foil with a porosity of 50% and a pore size of 15 μm, and then transfer it to an oven for drying at 80°C; after the dried electrode is pressed under a pressure of 2 MPa, it is cut into 50 mm × 75 mm, and the first negative electrode ear is spot welded, with a surface density of 10 mg / cm 2 ;

[0082] 4. Preparation of lithium supplement electrode: Cut lithium foil into 50mm×75mm pole pieces, and weld two lithium foil electrode tabs together to serve as the third electrode (lithium supplement electrode);

[0083] 5. Assemble the battery: assemble the first positive electrode, diaphragm, negative electrode, diaphragm, second positive electrode, diaphragm, negative electrode and first positive electrode in sequence according to the laminated battery process. After the assembly is completed and a layer of diaphragm is wound, the two lithium foil electrodes of the prepared lithium supplement electrode are placed on the left and right sides of the dry battery cell respectively. Then, after packaging, liquid injection and standing, 10kgf / cm2 is continuously applied to the entire surface of the battery. 2 The pre-charging is carried out at the same time as the pressure, and then the degassing packaging and capacity testing are carried out;

[0084] 6. Battery charge and discharge performance test: Connect the positive and negative poles of the battery to the positive and negative poles at 5 mA / cm 2 The current was constant for 24 min, with a charging capacity of 1.6 Ah. Then the positive electrode and the lithium supplement electrode were switched at 5 mA / cm 2The current is constant current discharge, the cut-off voltage is 4.4V, and the charging capacity is 2.8Ah; the total capacity of the two-stage charging is 4.4Ah. Then disconnect and connect the positive and negative poles at 5mA / cm 2 The constant current charging is 24 minutes, and the charging capacity is 1.6Ah.

[0085] Comparative Example 1

[0086] Comparative Example 1 is a three-electrode lithium-ion battery containing a lithium supplement electrode. The positive and negative current collectors both use porous metal foils with a porosity of 50% and an average pore size of 15 μm. Other aspects are the same as in Example 1. A lithium-ion battery is prepared. After standing, aging, and formation, charge and discharge cycle tests are performed. The test results are shown in Table 1 below.

[0087] Comparative Example 2

[0088] Comparative Example 2 is a conventional battery, in which both the positive and negative current collectors use non-porous metal foils, and the rest is the same as in Example 1. A lithium-ion battery is prepared, and after standing, aging, and formation, charge and discharge cycle tests are performed. The test results are shown in Table 1 below.

[0089] Table 1. Performance test results

[0090]

[0091] Combining the test results of the embodiments, comparative examples and Table 1, it can be seen that the first charge efficiency and battery capacity of the battery in the specific embodiments of the utility model are significantly higher than those of the comparison group.

[0092] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials, or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the utility model. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example.

[0093] Although the embodiments of the present invention have been shown and described, those skilled in the art will appreciate that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the claims and their equivalents.

Claims

1. A battery, characterized in that: The method comprises at least one subunit, wherein the subunit comprises a first lithium supplement electrode and a current collector unit, wherein a plurality of holes are formed on the current collector unit; in the subunit, the current collector unit satisfies: The pore sizes of the plurality of pores tend to increase in a direction away from the first lithium supplementing electrode; and / or The porosity tends to increase in a direction away from the first lithium supplement electrode; and / or The current collector unit includes a first current collector and a second current collector. The second current collector is disposed on a side of the first current collector away from the first lithium supplementing electrode. The thickness of the second current collector is smaller than that of the first current collector.

2. The battery according to claim 1, characterized in that In the subunit, the current collector unit includes a first current collector and a second current collector, and the second current collector is arranged on a side of the first current collector away from the first lithium supplement electrode; the current collector unit satisfies: The average pore size of the second current collector is greater than the average pore size of the first current collector; and / or The porosity of the second current collector is greater than the porosity of the first current collector.

3. The battery according to claim 1, characterized in that The battery includes a plurality of the subunits, and the plurality of the subunits are stacked.

4. The battery according to claim 3, characterized in that The invention comprises a first lithium-supplementing electrode, a separator, a first electrode, a separator, a second electrode, a separator, a third electrode, a separator, a fourth electrode, a separator and a first lithium-supplementing electrode stacked in sequence, wherein the first electrode comprises the first current collector, the second electrode comprises the second current collector, the third electrode comprises the second current collector, and the fourth electrode comprises the first current collector.

5. The battery according to any one of claims 1 to 4, characterized in that: At least one of the first current collector and the second current collector is a porous metal foil.

6. The battery according to any one of claims 1 to 4, characterized in that: The pore diameter is d1, wherein d1 satisfies: 1 μm≤d1≤1000 μm; and / or The porosity is a1, wherein a1 satisfies: 1%≤a1≤90%; and / or At least one of the first current collector and the second current collector has a thickness of h1, wherein h1 satisfies: 1 μm≤h1≤20 μm.

7. The battery according to claim 6, characterized in that The d1 satisfies: 2 μm ≤ d1 ≤ 500 μm; and / or a1 satisfies: 10%≤a1≤60%; and / or The h1 satisfies: 2μm≤h1≤8μm.

8. The battery according to claim 7, characterized in that The d1 satisfies: 3 μm≤d1≤50 μm; and / or The a1 satisfies: 30%≤a1≤40%.

9. The battery according to any one of claims 1 to 4, characterized in that: The first lithium-supplementing electrode includes a lithium-supplementing layer, and the lithium-supplementing layer includes at least one of a lithium layer, a lithium-silicon alloy layer, a lithium-aluminum alloy layer, a lithium-boron alloy layer, and a lithium-magnesium alloy layer.

10. The battery according to claim 9, characterized in that The thickness of the lithium supplement layer is h2, wherein h2 satisfies: 20 μm≤h2≤1 mm.

11. The battery according to claim 10, characterized in that The h2 satisfies: 20μm≤h2≤700μm.

12. The battery according to claim 9, characterized in that The first lithium supplement electrode further includes a lithium supplement current collector, and the lithium supplement layer is disposed on the lithium supplement current collector.

13. A battery assembly, characterized in that: Comprising a battery according to any one of claims 1-12.

14. An electrical device, characterized in that: The method comprises a battery according to any one of claims 1 to 12, or a battery assembly according to claim 13.

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