CN214411252U

CN214411252U - Current collector, battery and object

Info

Publication number: CN214411252U
Application number: CN202022202387.2U
Authority: CN
Inventors: 魏凤杰; 王晓明; 张磊; 韩冰
Original assignee: Jiangsu Zhuogao New Material Technology Co Ltd
Current assignee: Jiangsu Zhuogao New Material Technology Co Ltd
Priority date: 2020-09-30
Filing date: 2020-09-30
Publication date: 2021-10-15
Anticipated expiration: 2030-09-30

Abstract

The application discloses mass flow body, battery relates to secondary battery technical field. This application is through will passing through the first foil and the second foil complex of calendering in the substrate both sides with the adhesive, and rethread alkali solution disappears first foil and second foil to required thickness, can enough guarantee the inseparable complex between substrate and the foil, has also improved the density of foil through the calendering for the compound mass flow body can soak the test through electrolyte, has higher security performance. Meanwhile, the technical scheme of the application has small investment, the process flow is similar to that of a cleaning machine, the equipment has low cost compared with a vacuum coating machine, the production can be rapidly expanded depending on domestic equipment manufacturers, and the stable and continuous production is easier to realize compared with the prior art.

Description

Current collector, battery and object

Technical Field

The present disclosure relates to secondary batteries, and particularly to a current collector, a battery, and an object.

Background

The current collector is a main component of the lithium ion secondary battery and is used for bearing positive and negative electrode active substances and collecting and conducting electrons. In a common configuration, a copper foil material is used for the negative electrode, and an aluminum foil material is used for the positive electrode. Because of the use of metal materials, the positive and negative current collectors occupy a large proportion (about 8%) in the total weight of the battery core, so that the reduction of the weight of the current collectors is an effective method for improving the energy density (kWh/kg) of the lithium ion battery, the minimum thickness of the current aluminum foil product is 9 μm, the minimum thickness of the copper foil is 6 μm, and the thickness approaches the limit due to process limitations.

In contrast, chinese patent application publication No. CN106960960A discloses a "flexible current collector for improving cycle performance of a negative electrode material of a lithium ion battery", which is a nodular negative current collector material prepared by a simple two-step method of electrodeposition and high-temperature annealing; the current collector adopts carbon fiber cloth as a base material for electrodeposition. Secondly, the chinese invention patent with publication number CN109599563A discloses a "lithium ion battery current collector", which includes a flexible substrate and a conductive plating layer coated on the surface of the flexible substrate, wherein the conductive plating layer includes a chemical plating layer and an electroplated layer from inside to outside.

The technical scheme has the following disadvantages: 1) the investment is large, the production efficiency is low, and the stable and continuous production is particularly difficult to realize; 2) the compactness of an electric deposition layer or an electric plating layer is difficult to control, and the electrolyte is easy to fall off after soaking.

Disclosure of Invention

The application aims to provide a preparation method of a current collector, and the current collector solves the problems in the prior art.

In order to achieve the above purpose, the embodiments of the present application adopt the following technical solutions: a method of making a current collector, comprising the steps of:

compounding; coating an adhesive on the surface of a base material, and compounding a rolled foil on the surface to obtain a composite film;

soaking and etching: soaking the composite membrane in an alkaline solution;

and (3) spray drying: spraying and washing the soaked and etched composite film, drying and rolling;

wherein, the thickness of the foil subjected to soaking and etching is H, and H satisfies the following relational expression: 0.75 μm < H <5 μm;

the surface of the foil subjected to the soaking and etching is provided with a pit with the diameter of 1-10 mu m.

In above-mentioned technical scheme, this application embodiment is through compounding the first foil and the second foil that will pass through the calendering with the adhesive in substrate both sides, and rethread aqueous alkali disappears first foil and second foil to required thickness, can enough guarantee the inseparable complex between substrate and the foil, has also improved the density of foil through the calendering for compound mass flow body can pass through electrolyte and soak the test, has higher security performance. Meanwhile, the technical scheme of the application has small investment, the process flow is similar to that of a cleaning machine, the equipment has low cost compared with a vacuum coating machine, the production can be rapidly expanded depending on domestic equipment manufacturers, and the stable and continuous production is easier to realize compared with the prior art.

Further, according to the embodiment of the application, in the compounding step, a first foil is compounded on the first surface of the base material through first compounding, a second foil is compounded on the second surface of the base material through second compounding, the compounding temperature in the first compounding and the compounding temperature in the second compounding are both greater than or equal to 90 ℃, and the compounding pressure is both greater than or equal to 0.4 MPa.

Further, according to the embodiment of the application, after the first compounding, the compounded substrate is placed at 50 ℃ for 24 hours to be subjected to primary curing.

Further, according to the embodiment of the application, after the second compounding, the compounded substrate is placed at 50 ℃ for 72 hours.

Further, according to the embodiment of the present application, wherein the composite film is cured at a temperature of 80-90 ℃ for 72 hours before the immersion etching step.

Further, according to the embodiment of the present application, wherein the foil is made of aluminum, copper, nickel, silver, gold, carbon, stainless steel or an alloy thereof.

In order to achieve the above object, an embodiment of the present application further discloses a current collector, including: a substrate; the foil is compounded on two sides of the base material, the thickness of the foil on one side is H, and the H satisfies the following relational expression: 0.75 μm < H <5 μm; the surface of the foil is provided with pits with the diameter of 1-10 mu m.

Further, according to the embodiment of the present application, wherein the thickness of the substrate is 1.5 to 8 μm.

Further, according to the embodiment of the present application, a glue layer is disposed between the foil and the substrate.

Further, according to the embodiment of the application, the thickness of the glue layer is 0.5-2 μm.

In order to achieve the above object, an embodiment of the present application further discloses a battery, which includes a positive electrode plate, a negative electrode plate, a separator and an electrolyte, wherein the positive electrode plate and/or the negative electrode plate has a current collector as described above.

In order to achieve the purpose, the embodiment of the application also discloses an object, and the object is provided with the battery.

Further, according to the embodiment of the application, the object is an electronic product or an electric vehicle.

Compared with the prior art, the method has the following beneficial effects: this application will pass through the first foil and the second foil complex of calendering in the substrate both sides through using the adhesive, and rethread alkali solution disappears first foil and second foil to required thickness, can enough guarantee the inseparable complex between substrate and the foil, has also improved the density of foil through the calendering for the compound mass flow body can soak the test through electrolyte, has higher security performance. Meanwhile, the technical scheme of the application has small investment, the process flow is similar to that of a cleaning machine, the equipment has low cost compared with a vacuum coating machine, the production can be rapidly expanded depending on domestic equipment manufacturers, and the stable and continuous production is easier to realize compared with the prior art.

Drawings

The present application is further described below with reference to the drawings and examples.

Fig. 1 is a flow chart of a method of making a current collector in the present application.

Fig. 2 is a surface topography of the aluminum foil of the present application before thinning.

Fig. 3 is a surface topography of the aluminum foil of the present application after thinning.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention clear and fully described, embodiments of the present invention are further described in detail below with reference to the accompanying drawings. It is to be understood that the specific embodiments described herein are merely illustrative of some embodiments of the invention and are not limiting of the invention, and that all other embodiments obtained by those of ordinary skill in the art without the exercise of inventive faculty are within the scope of the invention.

In the description of the present invention, it should be noted that the terms "center", "middle", "upper", "lower", "left", "right", "inner", "outer", "top", "bottom", "side", "vertical", "horizontal", and the like indicate orientations or positional relationships based on those shown in the drawings, and are only for convenience of description and simplicity of description, but do not indicate or imply that the referred device or element must have a specific orientation, be constructed in a specific orientation, and be operated, and thus, should not be construed as limiting the present invention. Furthermore, the terms "a," "an," "first," "second," "third," "fourth," "fifth," and "sixth" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.

In the description of the present invention, it should be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.

For the purposes of simplicity and explanation, the principles of the embodiments are described by referring mainly to examples. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the embodiments. It will be apparent, however, to one skilled in the art that the embodiments may be practiced without these specific details. In some instances, well-known methods and structures have not been described in detail so as not to unnecessarily obscure the embodiments. In addition, all embodiments may be used in combination with each other.

Fig. 1 illustrates a method of making a current collector in the present application. As shown in fig. 1, the current collector preparation method includes the following steps:

s10, primary compounding; coating an adhesive on the first surface of the base material, and compounding the calendered first foil on the first surface;

s20, secondary compounding: coating an adhesive on the second surface of the base material, and compounding the calendered second foil on the second surface;

s30, soaking and etching: soaking the composite film obtained through the primary compounding and the secondary compounding in an alkaline solution;

s40, spray drying: and (4) spraying and washing the soaked and etched composite membrane, drying and rolling.

In above-mentioned technical scheme, this application will pass through the first foil and the second foil complex of calendering in substrate both sides through using the adhesive, and rethread aqueous alkali disappears first foil and second foil to required thickness, can enough guarantee the inseparable complex between substrate and the foil, has also improved the density of foil through the calendering for the compound mass flow body can pass through electrolyte and soak the test, has higher security performance. Meanwhile, the technical scheme of the application has small investment, the process flow is similar to that of a cleaning machine, the equipment has low cost compared with a vacuum coating machine, the production can be rapidly expanded depending on domestic equipment manufacturers, and the stable and continuous production is easier to realize compared with the prior art.

In order to ensure the safety performance of the battery with the composite film, the first foil and the second foil which are soaked and etched thick are limitedIs measured. Setting the thickness of the first foil subjected to soaking etching to be H₁The thickness of the second foil is H₂. Preferably, H₁And H₂Satisfies the following relation: 0.75 μm<H₁<5μm；0.75μm<H₂<5 μm. On the other hand, if the thickness of the foil is less than 1 μm, especially less than 0.75 μm, it is not favorable for the current collector to generate sufficient current; if the thickness of the foil is greater than 5 μm, the safety performance of the battery cell may be deteriorated.

In addition, in steps S10 and S20, the compounding temperature is preferably 90 ℃ or higher, and the compounding pressure is preferably 0.4MPa or higher, i.e., under allowable conditions, the higher the compounding temperature and the compounding pressure, the better the compounding firmness between the first foil, the second foil and the substrate is ensured.

Next, in step S10, after completing the primary compounding, the substrate is left at 50 ℃ for 24 hours to be primarily cured. In step S20, after the secondary compounding is completed, the substrate is left at 50 ℃ for 72 hours for further curing. Before the step S30, the composite film is cured for 72h at the temperature of 80-90 ℃.

In addition, in step S30, the soaking temperature is 40-50 ℃, the soaking time is 0.5-2min, and the Ph of the alkali solution is 9-10. In this regard, the amount of foil thinning may be controlled by controlling the soaking temperature, soaking time, and concentration of the alkaline solution, respectively. Specifically, the alkali solution is preferably NaOH solution, and the concentration is controlled within the range of 10-15%.

Taking an aluminum foil as an example, the surface of the aluminum foil before soaking and etching is shown in fig. 2, the surface of the aluminum foil after soaking and etching is shown in fig. 3, and the processed aluminum surface has obvious micro-morphology change compared with the common aluminum foil, specifically, pit structures 1 with the surface of 1-10 μm are distributed.

Further, the base material is made of one or more of PET, PP, PE, PI, and polyarylsulfone, or other light-weight and strong insulating materials may be used instead to provide a supporting force and reduce the mass of the current collector. Preferably, the thickness of the substrate is 1.5-8 μm, and an excessively thin substrate is easily corroded by the alkali solution in step S30, weakening the supporting ability, and affecting the safety performance of the lithium ion battery.

Furthermore, the foil is made of aluminum, copper, nickel, silver, gold, carbon, stainless steel or alloy thereof. Conventionally, the foil used as the positive current collector is generally formed by pressing aluminum or an aluminum alloy, and the foil used as the negative current collector is generally formed by pressing copper or a copper alloy.

Further, the thickness of the adhesive is 0.5-2 μm. In this thickness range, the gluing agent can provide sufficient adhesive force in order to guarantee compound fastness between substrate and the foil, simultaneously, can not excessively increase the thickness of mass flow body so that influence the performance of battery. Wherein the adhesive is CY-C612 adhesive produced by Donggugjie new energy factory.

The technical solutions of the present application are further illustrated by the following examples 1 to 8, but the present application is not limited to these examples.

The details of the current collectors of examples 1-8 are shown in table 1.

TABLE 1

Lithium batteries were made from the above current collectors to obtain examples 9-14, as shown in table 2.

TABLE 2

	Positive current collector	Negative current collector
			Example 9	Example 1	Example 5
Example 10	Example 2	Example 8
			Example 11	Example 3	Example 7
Example 12	Example 4	Example 8
			Example 13	Example 1	Example 5
Example 14	Example 3	Example 7

To demonstrate the effect of the present application, the following current collectors in comparative examples 1 to 6 were introduced for comparison with examples 1 to 8 of the present application. The details of comparative examples 1 to 6 are shown in Table 3.

TABLE 3

The current collectors of the above comparative examples were fabricated into secondary batteries, as shown in Table 4

TABLE 4

	Positive current collector	Negative current collector
			Comparative example 7	Example 1	Comparative example 4
Comparative example 8	Example 2	Comparative example 5
			Comparative example 9	Example 1	Comparative example 6
Comparative example 10	Comparative example 1	Example 5
			Comparative example 11	Comparative example 2	Example 5
Comparative example 12	Comparative example 3	Example 7

The secondary batteries of examples 9 to 14 and comparative examples 7 to 12 were subjected to a Nail penetration test (Nail), an Impact test (Impact), a Crush test (Crush) and a battery Cycle test (Cycle), all in accordance with the UN38.3 lithium battery test standard. The test results are shown in table 5.

TABLE 5

	Nail	Impact	Crush	Cycle
					Example 9	Pass	Pass	Pass	Pass
Example 10	Pass	Pass	Pass	Pass
					Example 11	Pass	Pass	Pass	Pass
Example 12	Pass	Pass	Pass	Pass
					Example 13	Pass	Pass	Pass	Pass
Example 14	Pass	Pass	Pass	Pass
					Comparative example 7	NG	NG	NG	Pass
Comparative example 8	Pass	Pass	Pass	NG
					Comparative example 9	Pass	Pass	Pass	Pass
Comparative example 10	Pass	Pass	Pass	NG
					Comparative example 11	NG	NG	NG	Pass
Comparative example 12	Pass	Pass	Pass	Pass

Although the illustrative embodiments of the present application have been described above to enable those skilled in the art to understand the present application, the present application is not limited to the scope of the embodiments, and various modifications within the spirit and scope of the present application defined and determined by the appended claims will be apparent to those skilled in the art from this disclosure.

Claims

1. A current collector, comprising:

a substrate;

the foil is compounded on two sides of the base material, the thickness of the foil on one side is H, and the H satisfies the following relational expression: 0.75 μm < H <5 μm; the surface of the foil is provided with pits with the diameter of 1-10 mu m.

2. The current collector of claim 1, wherein the thickness of the substrate is 1.5-8 μm.

3. The current collector of claim 1, wherein a glue layer is disposed between the foil and the substrate.

4. A current collector as claimed in claim 3, wherein said glue layer has a thickness of 0.5-2 μm.

5. A battery comprising a positive electrode sheet, a negative electrode sheet, a separator and an electrolyte, wherein the positive electrode sheet and/or the negative electrode sheet has a current collector as claimed in any one of claims 1 to 4.

6. An object, characterized in that the object is provided with a battery according to claim 5.

7. An object according to claim 6, characterized in that the object is an electronic product or an electric vehicle.