lithium-ion battery

Abstract

A lithium-ion battery is disclosed. The lithium-ion battery comprises: a positive current collector having a positive active material disposed on its surface; a negative current collector having a negative active material disposed on its surface and a negative current collector disposed opposite to the positive current collector; a separator and an electrolyte disposed between the positive active material and the negative active material; a positive column electrically in contact with the positive current collector; a negative column electrically in contact with the negative current collector; and an outer housing surrounding the positive current collector, the negative current collector, the separator and the electrolyte, through which the positive column and the negative column pass; and a structure having a surface of the positive current collector and a surface of the negative current collector that is regularly and / or randomly textured.

Description

Technology Field

[0001] This invention relates to the field of batteries, and in particular to lithium-ion batteries. Background Technology

[0002] Rechargeable lithium-ion batteries generally have one or more electrochemical cells, each having a negative electrode, a positive electrode, and an electrolyte for transferring lithium ions between the negative and positive electrodes. A porous separator moistened with a liquid electrolyte solution may be interposed between the negative and positive electrodes to physically separate them from each other and electrically insulate them while allowing free ion flow. Each of the negative and positive electrodes is typically accompanied by or connected to a metal current collector. The current collectors may be connected to each other by an interruptible external circuit, through which electrons can pass from one electrode to another during the charging and discharging of the battery, and simultaneously, lithium ions can move in the opposite direction through the electrochemical cell.

[0003] During discharge, the negative electrode contains a relatively high concentration of intercalated lithium, which is oxidized into lithium ions and electrons. Lithium ions move from the negative electrode (cathode) to the positive electrode (anode) through the electrolyte (i.e., through the porous separator). At the same time, electrons are transferred from the negative electrode to the positive electrode through an external circuit. Lithium ions are assimilated into the material of the positive electrode by an electrochemical reduction reaction. The battery can be recharged by an external power source after partial or complete discharge of its available capacity, and this recharging occurs in the reverse of the electrochemical reaction that occurs during discharge.

[0004] During recharging, the lithium embedded within the anode is oxidized into lithium ions and electrons. Lithium ions move from the anode to the cathode via the electrolyte (i.e., through the porous separator), and electrons are transferred to the cathode through an external circuit. At the cathode, lithium cations are reduced to elemental lithium and stored within the cathode material for reuse. means of solving the problem

[0005] The present invention provides a lithium-ion battery, and such a lithium-ion battery increases the contact surface area between a positive current collector and a negative current collector, thereby reducing the internal conductive resistance of the positive current collector and the negative current collector and increasing the electrical conductivity of the positive current collector and the negative current collector. In addition, by coating a conductive material on the positive current collector and the negative current collector, respectively, the internal conductive resistance can be further reduced and the electrical conductivity can be further increased.

[0006] In an embodiment of the present invention, a lithium-ion battery is provided. The lithium-ion battery comprises: a positive current collector—where a positive active material is disposed on the surface of the positive current collector—; a negative current collector—where a negative active material is disposed on the surface of the negative current collector, and the negative current collector is disposed opposite to the positive current collector—; a separator and an electrolyte disposed between the positive active material and the negative active material; a positive column electrically in contact with the positive current collector; a negative column electrically in contact with the negative current collector; and an outer housing surrounding the positive current collector, the negative current collector, the separator and the electrolyte—where the positive column and the negative column pass through the outer housing—and a textured structure in which the surface of the positive current collector and the surface of the negative current collector are regularly and / or randomly textured.

[0007] Optionally, in some embodiments, a conductive material layer having a thickness in the range of 0.5 microns to 2 microns is disposed between the positive current collector and the positive active material, and between the negative current collector and the negative active material, respectively.

[0008] Optionally, in some embodiments, the conductive material layer is formed of graphene and / or carbon nanotubes.

[0009] Optionally, in some embodiments, the positive current collector is made of aluminum foil with a thickness of 12 microns to 25 microns.

[0010] Optionally, in some embodiments, the negative current collector is made of copper foil with a thickness of 6 microns to 18 microns.

[0011] Optionally, in some embodiments, the positive active material comprises at least one of lithium manganite (LiMn2O4), lithium cobaltate (LiCoO2), and lithium iron phosphate (LiFePO4).

[0012] Optionally, in some embodiments, the cathode active material is graphite, a mixture of graphite and silicon, titanium dioxide (TiO2), and lithium titanate (Li4Ti5O2). 12 Includes at least one of ).

[0013] Optionally, in some embodiments, the textured structure includes a plurality of dimples within the surface.

[0014] Optionally, in some embodiments, each of the plurality of dimples has a depth greater than 0 and less than 5 microns, and an opening diameter greater than 0 and less than 100 microns.

[0015] Optionally, in some embodiments, the surface of the positive current collector, the surface of the negative current collector, and the surface of the plurality of dimples further comprise a randomly textured structure obtained by surface roughening. Brief explanation of the drawing

[0016] In order to explain the technical solution of the embodiment of the present invention more clearly, the drawings used in the description of the embodiment are briefly introduced below. Of course, the drawings in the following description are merely some embodiments of the present invention, and a person skilled in the art will be able to obtain other drawings based on these drawings without creative work. FIG. 1 is a schematic structural diagram of a lithium-ion battery according to an embodiment of the present invention. Figure 2 is a schematic diagram of the structure of a current collector within a lithium-ion battery shown in Figure 1. FIG. 3 is a cross-sectional view of the entire house shown in FIG. 2, taken along plane (F) and observed along direction (AA). Figure 4 schematically illustrates the situation after the current collector shown in Figure 2 has been treated with surface conditioning. It should be understood that the drawings are used merely to illustrate embodiments and, accordingly, are not necessarily to actual scale. Similar reference numerals in the drawings indicate identical or similar components, elements, and parts. Specific details for implementing the invention

[0017] Hereinafter, the technical solution of the embodiment of the present invention will be described clearly and completely together with the drawings of the embodiment of the present invention. Of course, the described embodiment is merely some of the embodiments of the present invention and is not all of them. All other embodiments that can be obtained by a person skilled in the art without creative work based on the embodiment of the present invention will be included within the scope of protection of the present invention.

[0018] In an embodiment of the present invention, a lithium-ion battery is provided. Referring to FIG. 1, the lithium-ion battery (100) comprises: a positive current collector (101) - a positive active material (102) disposed on the surface of the positive current collector (101) -; a negative current collector (104) - a negative active material (107) disposed on the surface of the negative current collector (104), and the negative current collector (104) disposed opposite the positive current collector (101) -; a separator and an electrolyte (103) disposed between the positive active material (102) and the negative active material (107); a positive column (106) electrically contacted with the positive current collector (101); a negative column (105) electrically contacted with the negative current collector (104); and an outer housing (108) surrounding the positive current collector (101), the negative current collector (104), the separator, and the electrolyte (103) - the positive column (102) and the negative column (104) pass through the outer housing (108) -; the surface of the positive current collector (101) and the surface of the negative current collector (104) include a structure in which the surface is regularly and / or randomly textured. The separator and the electrolyte (103) are a series of " between the positive current collector (101) and the negative current collector (104) It should be understood that in this disclosure, the term “regularly textured structure” refers to a textured structure formed on the surface of a current collector by arranging microstructures having a specific shape and structure in the form of an array according to a specific rule, as described below with reference to FIG. 2, and the term “randomly textured structure” refers to a textured structure formed on the surface of a current collector by arranging microstructures without a specific shape and structure in the form of an array according to a specific rule. Accordingly, in this disclosure, the term “randomly textured structure” also includes a textured surface of a tempered surface formed on the surface of a current collector by a suitable surface tempering treatment.

[0019] In an embodiment of the present invention, the positive current collector (101) may be made of aluminum foil with a thickness of 12 to 25 microns. In another embodiment of the present invention, the negative current collector may be made of copper foil with a thickness of 6 to 18 microns. In the lithium-ion battery (100) of the present invention, by surface-treating the positive current collector (101), its surface area is increased by at least 1.5 times the original base, thereby reducing the internal conductivity resistance of the aluminum foil and increasing its conductivity; additionally, by surface-treating the negative current collector (104), its surface area is increased by at least 1.3 times the original base, thereby reducing the internal conductivity resistance of the copper foil and increasing its electrical conductivity. By doing so, the high-speed charging and discharging capability of the lithium-ion battery (100) can be realized.

[0020] In an embodiment of the present invention, a conductive material layer having a thickness of 0.5 microns to 2 microns may be disposed between a positive current collector (101) and a positive active material (102). Optionally, a conductive material layer having a thickness of 0.5 microns to 2 microns may also be disposed between a negative current collector (104) and a negative active material (107). In an embodiment of the present invention, the conductive material layer is formed of graphene and / or carbon nanotubes.

[0021] Aluminum is 2.83×10 -8 It has a resistivity of Ωm, and copper is 1.75×10⁻⁶ -8 It has a resistivity of Ωm, and graphene and carbon nanotubes have a smaller resistivity. Therefore, by providing a conductive material layer formed by graphene and / or carbon nanotubes, the internal conductive resistance of the positive current collector (101) and the negative current collector (104) can be further reduced, and accordingly, the electrical conductivity can be increased.

[0022] Optionally, in some embodiments, the positive active material (102) may comprise at least one of lithium manganite (LiMn2O4), lithium cobaltate (LiCoO2), and lithium iron phosphate (LiFePO4).

[0023] Optionally, in some embodiments, the cathode active material (107) may comprise at least one of graphite, a mixture of graphite and silicon, titanium dioxide (TiO2), and lithium titanate (Li4Ti5O12).

[0024] Referring to FIG. 2, FIG. 2 schematically illustrates the structure of a current collector (101 and 104) within a lithium-ion battery illustrated in FIG. 1. As illustrated in FIG. 2, the current collector (101, 104) has a first surface (301) and an opposing second surface (302). A plurality of circular dimples (303) may be provided on the first surface (301) to form a textured structure on the surface. It should be understood that the shape of the dimples (303) may also be any other suitable shape, e.g., triangular, rectangular, elliptical, etc., and that the shape of the dimples (303) is not specifically limited herein. Optionally, in some embodiments, a plurality of dimples (303) may also be provided on the second surface (302).

[0025] Referring to FIG. 3 in conjunction with FIG. 2, a cross-sectional view of the current collector (101, 104) of FIG. 2 is shown, taken along plane (F) and observed along direction (AA). As shown in FIG. 3, each dimple (303) has a depth (h) and an opening diameter (W). Optionally, in some embodiments, the depth (h) may be in the range greater than 0 and less than or equal to 5 microns, and the opening width (W) may be in the range greater than 0 and less than or equal to 100 microns. It should be noted that FIG. 2 and FIG. 3 merely illustrate exemplary embodiments of a textured structure on the surface of the current collector and that the textured structure on the surface of the current collector according to the present invention is not limited to such. For example, the first surface (301) and / or the second surface (302) may, alternatively or additionally, have at least one of a plurality of protrusions, a plurality of concave-convex stripes, and a plurality of grids.

[0026] Referring to FIG. 4, FIG. 4 schematically illustrates the situation after surface conditioning treatment is performed on the current collector (101, 104) illustrated in FIG. 2. If the first surface (301) and / or the second surface (302) has a plurality of dimples (303), the current collector (101, 104) may be surface conditioning treated with a suitable chemical reagent, thereby conditioned the surfaces of the first surface (301), the second surface (302), and the plurality of dimples (303) to additionally obtain a randomly textured structure, thereby further increasing the specific surface area of ​​the current collector (101 and 104), further reducing its internal conductivity resistance, and further increasing its conductivity. Alternatively, in some embodiments, the chemical reagent may be hydrochloric acid or sulfuric acid.

[0027] The indefinite articles (“a” and “an”) as used in the specification and claims of this application should be understood to mean “at least one” unless explicitly indicated otherwise.

[0028] The phrase “and / or” as used in the specification and claims of this application should be understood to mean “either one or both” of the elements thus combined, that is, elements that exist combined in some cases and separately in others. The various elements listed by “and / or” should be interpreted in the same way, that is, “one or more” of the elements should be interpreted as being thus combined. Other elements other than those specifically identified by the “and / or” phrase may optionally exist, whether or not they are related to the specifically identified elements. Accordingly, as a non-limiting example, a reference to “A and / or B” may, when used with open-ended language such as “comprising,” refer to A only (optionally including elements other than B) in one embodiment; B only (optionally including elements other than A) in another embodiment; and both A and B (optionally including other elements) in yet another embodiment, etc.

[0029] As used in the specification and claims of this application, in reference to a list of one or more elements, the phrase “at least one” means at least one element selected from any one or more elements within the list of elements, but must not necessarily include at least one of each and all elements specifically listed within the list of elements, nor exclude any combination of elements within the list of elements. This definition also allows an element to optionally exist other than the element specifically identified within the list of elements where the phrase “at least one” is cited, whether or not it is related to the specifically identified element. Accordingly, as a non-limiting example, “at least one of A and B” (or, equivalently, “at least one of A or B” or, equivalently, “at least one of A and / or B”) may refer to: in one embodiment, at least one A (optionally including more than one A) where B is not present (and optionally includes an element other than B); In another embodiment, A may refer to at least one B (optionally including more than one B) which is not present (and optionally includes an element other than A); in yet another embodiment, A may refer to at least one A (optionally including more than one A) and at least one B (optionally including more than one B) (and optionally including another element); etc.

[0030] In the claims and in the aforementioned specification, all transitional phrases such as “include,” “have,” “accompany,” “have,” “embed,” “contain,” “include,” “related,” “maintain,” and “consist of” should be understood as open, that is, as including but not being limited to. Only the transitional phrases “consisting of” and “essentially composed of” will be closed or semi-closed transitional phrases, respectively.

[0031] The foregoing is merely an embodiment of the present invention, and the scope of protection of the present invention is not limited thereto. Any person skilled in the art familiar with the art will readily conceive of modifications or substitutions that should be included within the scope of protection of the present invention within the scope of the art disclosed herein. Accordingly, the scope of protection of the present invention should be based on the scope of protection of the claims.

Claims

Claim 1 A lithium-ion battery comprising: a positive current collector - a positive active material disposed on the surface of the positive current collector -; a negative current collector - a negative active material disposed on the surface of the negative current collector, and the negative current collector disposed opposite the positive current collector -; a separator and an electrolyte disposed between the positive active material and the negative active material; a positive column electrically in contact with the positive current collector; a negative column electrically in contact with the negative current collector; A lithium-ion battery comprising: an outer housing surrounding the positive current collector, the negative current collector, the separator, and the electrolyte, wherein the size of the outer housing in the thickness direction of the positive column and the negative column is greater than the thickness of the outer housing so that the positive column and the negative column pass through the outer housing; wherein the surface of the positive current collector and the surface of the negative current collector comprise a plurality of regularly arranged dimples, and the surface of the positive current collector, the surface of the negative current collector, and the surface of the plurality of dimples further comprise randomly textured structures obtained by surface conditioning treatment with a chemical reagent, and wherein the randomly textured structures comprise microstructures arranged without any specific shape or structure and without any regularity. Claim 2 A lithium-ion battery according to claim 1, wherein a conductive material layer having a thickness in the range of 0.5 microns to 2 microns is disposed between the positive current collector and the positive active material, and between the negative current collector and the negative active material, respectively. Claim 3 A lithium-ion battery according to paragraph 2, wherein the conductive material layer is formed of graphene and / or carbon nanotubes. Claim 4 A lithium-ion battery according to claim 1, wherein the positive current collector is made of aluminum foil having a thickness of 12 microns to 25 microns. Claim 5 A lithium-ion battery according to claim 1, wherein the negative current collector is made of copper foil having a thickness of 6 microns to 18 microns. Claim 6 A lithium-ion battery according to claim 1, wherein the positive active material comprises at least one of lithium manganite, lithium cobaltate, and lithium iron phosphate. Claim 7 A lithium-ion battery according to claim 1, wherein the negative electrode active material comprises at least one of graphite, a mixture of graphite and silicon, titanium dioxide, and lithium titanate. Claim 8 A lithium-ion battery according to claim 1, wherein each of the plurality of dimples has a depth greater than 0 and less than or equal to 5 microns, and an opening diameter greater than 0 and less than or equal to 100 microns. Claim 9 delete Claim 10 delete

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