CN217788450U

CN217788450U - Negative plate structure

Info

Publication number: CN217788450U
Application number: CN202221134157.XU
Authority: CN
Inventors: 代德明; 王浩; 周雷军; 王万胜
Original assignee: Wuhan Chuneng New Energy Co ltd
Current assignee: Wuhan Chuneng New Energy Co ltd
Priority date: 2022-05-11
Filing date: 2022-05-11
Publication date: 2022-11-11
Anticipated expiration: 2032-05-11

Abstract

The utility model provides a negative pole piece structure, include: current collector layer, first active material layer, second active material layer and carbon coating, first active material layer is attached to the surface of current collector layer, and the parallel array in one side that current collector layer was kept away from to first active material layer has seted up a plurality of recesses, the carbon coating covers the one side of keeping away from current collector layer at first active material layer, and each department thickness of carbon coating is the same, and one side that first active material layer was kept away from to the carbon coating is attached to have second active material layer, and the one side that carbon coating was kept away from to the second active material layer is on a parallel with current collector layer, first active material layer and second active material layer are silicon-based cathode material. The utility model discloses a negative pole piece structure has better structural stability, can improve the cycle life of battery.

Description

Negative plate structure

Technical Field

The utility model relates to a lithium cell technical field especially relates to a negative pole piece structure.

Background

At present, in order to overcome the problem of low gram capacity of the lithium ion battery negative electrode material, it is proposed to introduce a silicon-based negative electrode material with ultra-high gram capacity on the negative electrode material, and the manufacturing of the silicon-containing negative electrode plate still uses the traditional coating mode at present, namely, the silicon-containing negative electrode material is uniformly mixed with a conductive additive, a binder, a solvent and the like, and is pulped and then is covered on the surface of a metal current collector in a coating mode.

However, in the process of lithium intercalation and deintercalation of silicon-based negative electrode particles, the lithium-silicon alloy reaction can cause volume change of nearly 300% or more, so that in the process of charging and discharging of a silicon-containing negative film obtained by the traditional manufacturing method, particle pulverization, pole piece cracking, even falling of an active material from a metal current collector, continuous breakage and growth of an SEI film on the surface of a track particle are caused due to severe volume expansion and contraction effects, and finally, part of the active material cannot provide capacity, the internal resistance of a battery is increased, active lithium ions are continuously consumed, the cycle performance is deteriorated and the like.

How to reduce the internal stress of the silicon-containing negative plate, inhibit the cracking and pulverization of the active material and improve the cycle performance of the lithium ion battery becomes a technical problem to be solved urgently in the field.

SUMMERY OF THE UTILITY MODEL

In view of this, the utility model provides a more reasonable negative pole piece structure of structural design.

The technical scheme of the utility model is realized like this: the utility model provides a negative pole piece structure, it includes: the solar cell comprises a current collector layer, a first active material layer, a second active material layer and a carbon coating layer, wherein the first active material layer is attached to the surface of the current collector layer, a plurality of grooves are formed in one side parallel array of the first active material layer away from the current collector layer, the carbon coating layer covers one side of the first active material layer away from the current collector layer, the thickness of each part of the carbon coating layer is the same, the second active material layer is attached to one side of the carbon coating layer away from the first active material layer, one side of the second active material layer away from the carbon coating layer is parallel to the current collector layer, and the first active material layer and the second active material layer are silicon-based negative materials.

On the basis of the above technical solution, preferably, the thickness of the first active material layer is 20 to 100 μm.

On the basis of the above technical solution, preferably, the cross section of the groove is rectangular.

On the basis of the above technical solution, preferably, the cross section of the groove is square.

On the basis of the above technical solution, preferably, the depth of the groove is 10-80 μm.

On the basis of the above technical solution, preferably, the thickness of the carbon coating layer is 10 to 50nm.

In addition to the above technical solution, preferably, the thickness of the carbon coating layer is 25nm.

On the basis of the above technical solution, it is preferable that the thickness of the second active material layer is 20 to 200 μm.

On the basis of the above technical solution, preferably, the silicon content of the first active material layer is lower than that of the second active material layer.

On the basis of the technical scheme, preferably, the first active material layer is made of a SL400A-SOC nano carbon-silicon composite material produced by Liyang Tianmu lead battery material science and technology Limited.

On the basis of the technical scheme, preferably, the second active material layer is made of a SL500A-SOC nano carbon-silicon composite material produced by Liyang Tianmu lead battery material science and technology Limited.

The utility model discloses a negative pole piece structure has following beneficial effect for prior art:

(1) The utility model discloses a set up two kinds of active material layers to make and form the structure of mortise-tenon joint between two kinds of active material layers, this structure can be when two kinds of active material take place volume expansion and shrink to the stress that produces partly eliminate, thereby improved long-term charge-discharge process, battery active material's structural stability, effectively restrained the differentiation of material, the crackle of pole piece and the destruction scheduling problem of coming off and SEI membrane, prolonged cycle life;

(2) As a further preference, the first active material has a lower silicon content than the second active material, and therefore, has a lower expansion and contraction effect than the second active material, and therefore, a firm electrical contact between the first active material and the current collector can be ensured, while the first active material layer can also effectively support the second active material layer;

(3) Still set up the ann coating layer between first active material layer and second active material layer in this application, it not only can promote the inside electric conductive property name colleague of pole piece and has strengthened the cohesiveness between first active material layer and the second active material layer.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.

Fig. 1 is an axonometric view of the structure of the negative plate of the present invention;

fig. 2 is an exploded view of the structure of the negative plate of the present invention.

In the figure: 1-current collector layer, 2-first active material layer, 3-second active material layer, 4-carbon coating layer, 21-groove.

Detailed Description

The technical solutions in the embodiments of the present invention will be described clearly and completely below with reference to the embodiments of the present invention, and it is obvious that the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative work all belong to the protection scope of the present invention.

As shown in fig. 1, in conjunction with fig. 2, the negative plate structure of the present invention includes: current collector layer 1, first active material layer 2, second active material layer 3 and carbon coating 4, first active material layer 2 is attached to the surface of current collector layer 1, and a plurality of recesses 21 have been seted up to the parallel array in one side that current collector layer 1 was kept away from to first active material layer 2, carbon coating 4 covers the one side that current collector layer 1 was kept away from at first active material layer 2, and carbon coating 4 each department thickness is the same, and one side that first active material layer 2 was kept away from to carbon coating 4 is attached to second active material layer 3, and the one side that carbon coating 4 was kept away from to second active material layer 3 is on a parallel with current collector layer 1, first active material layer 2 and second active material layer 3 are silicon-based negative pole material.

In the above embodiment, adopt the form of similar mortise-tenon joint structure to carry out the embedding connection between first active material layer 2 and the second active material layer 3, still be provided with the carbon coating between two kinds of active material layers, when two kinds of active material all take place the inflation, other single component structure is compared to mortise-tenon joint's part, owing to there are more contact surfaces, consequently, can bear more stress, thereby the problem such as pulverization appears breaking when avoiding single material to take place the stress, and then can reduce the destruction to SEI membrane production, secondly, the carbon coating can promote the inside electric conductivity of pole piece, and the cohesiveness between first active material layer 2 and the second active material layer 3.

In a specific embodiment, the thickness of the first active material layer 2 is 20 to 100 μm.

In the above embodiment, in order to machine the groove 21 on the surface of the first active material layer 2, a laser etching method may be adopted, and the corresponding cladding layer may be a vapor deposition method.

In a particular embodiment, the cross-section of the groove 21 is rectangular.

The rectangular groove 21 is easier to machine.

Still further preferably, in a specific embodiment, the cross-section of the groove is square.

In the above embodiment, when the square groove 21 expands, the expansion volume in the bottom and side directions is relatively uniform, which is favorable for uniform stress.

In a particular embodiment, the depth of the grooves 21 is 10-80 μm.

In the above embodiment, the depth of the groove 21 does not exceed the thickness of the first active material layer 2, corresponding to the thickness requirement of the first active material layer 2.

In a specific embodiment, the thickness of the carbon coating layer 4 is 10 to 50nm.

In a specific embodiment, the thickness of the carbon coating layer 4 is 25nm.

In a specific embodiment, the thickness of the second active material layer 3 is 20 to 200 μm.

In the above embodiment, the thickness of the second active material layer 3 is the distance from the side of the second active material layer 3 away from the carbon coating layer 4 to the side of the carbon coating layer 4 away from the first active material layer 2 where the groove 21 is not provided.

In a specific embodiment, the first active material layer 2 is made of a Liyang Tianmu lead battery material technology Co., ltd, SL400A-SOC nano carbon silicon composite material.

In a specific embodiment, the second active material layer 3 is made of a Liyang Tianmu SL500A-SOC nano carbon-silicon composite material manufactured by Liyang Namo lead Battery materials technologies, inc.

Example 1

Uniformly coating a SL400A-SOC nano carbon-silicon composite material produced by Tianmu Pilot battery materials science and technology Limited on the surface of a metal current collector for baking, wherein the coating thickness is 80 mu m, then etching square grooves with equal intervals on the coating layer by using a pole piece laser etching device, wherein the groove width and the groove depth are both 40 mu m and the interval is 250 mu m, then depositing a carbon coating film on the coating layer by using a vapor deposition method, the thickness is 40nm, then uniformly coating the SL500A-SOC nano carbon-silicon composite material produced by Tianmu pilot battery materials science and technology Limited on the surface of the carbon coating layer, baking and cold pressing, and the coating thickness is 140 mu m to obtain a silicon-containing negative pole piece sample.

The silicon-containing negative pole piece is manufactured into a button type half cell: the silicon-containing negative pole piece is a positive pole, the metal lithium piece is a negative pole, the positive pole and the negative pole are separated by a separation film, and the 2025 button cell is assembled by using a gasket and a stainless steel shell.

Comparative example 1

Uniformly coating a SL500A-SOC nano carbon-silicon composite material produced by Liyang Tianmu lead battery material science and technology Limited on the surface of a metal current collector for baking, wherein the coating thickness is 180 mu m, and performing baking and cold pressing treatment to obtain a silicon-containing negative pole piece sample.

And (3) performance testing:

the battery was first charged and discharged using 0.1C rate, and then subjected to cycle performance testing using 0.5C rate at 25 ℃. The test result shows that the capacity retention rate of the embodiment 1 is obviously improved after 100 times of cycles of managers compared with the comparative example 1.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and should not be construed as limiting the present invention, and any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A negative electrode sheet structure, comprising: current collector layer (1), first active material layer (2), second active material layer (3) and carbon coating (4), first active material layer (2) are attached to the surface of current collector layer (1), and a plurality of recesses (21) have been seted up to one side parallel array that current collector layer (1) was kept away from in first active material layer (2), carbon coating (4) cover in one side that current collector layer (1) was kept away from in first active material layer (2), and carbon coating (4) every department thickness is the same, and one side that first active material layer (2) were kept away from in carbon coating (4) is attached to second active material layer (3), and the one side that carbon coating (4) were kept away from in second active material layer (3) is on a parallel with current collector layer (1), first active material layer (2) and second active material layer (3) are silicon-based negative pole material.

2. Negative electrode sheet structure according to claim 1, characterized in that the thickness of the first active material layer (2) is 20-100 μm.

3. Negative plate structure according to claim 1, characterized in that the cross-section of the groove (21) is rectangular.

4. A negative electrode sheet structure according to claim 1, wherein the cross-section of the groove (21) is square.

5. Negative plate structure according to claim 1, characterized in that the depth of the groove (21) is 10-80 μm.

6. The negative electrode sheet structure of claim 1, wherein the thickness of the carbon coating layer (4) is 10-50nm.

7. The negative electrode sheet structure of claim 6, wherein the carbon coating layer (4) has a thickness of 25nm.

8. Negative electrode sheet structure according to claim 1, characterized in that the thickness of the second active material layer (3) is 20-200 μm.