CN212257583U

CN212257583U - Novel rechargeable lithium-manganese button cell

Info

Publication number: CN212257583U
Application number: CN201922352591.XU
Authority: CN
Inventors: 郝德利; 叶丽光
Original assignee: TIANJIN HEWEI TECHNOLOGY CO LTD
Current assignee: TIANJIN HEWEI TECHNOLOGY CO LTD
Priority date: 2019-12-24
Filing date: 2019-12-24
Publication date: 2020-12-29
Anticipated expiration: 2029-12-24

Abstract

The utility model discloses a novel rechargeable lithium manganese button cell, negative pole are formed by bottom aluminum sheet/lithium piece/upper aluminum sheet three-layer at pressure 10~70MPa, through 5~10 minutes complex. The molar ratio of lithium to aluminum is (5-8): 10, the aluminum sheet is an embossed aluminum sheet with a purity of 99%, and the thickness of the upper aluminum sheet is as follows: thickness of the bottom aluminum sheet = 1: (2-3), the thickness of the upper layer aluminum sheet is 50-100 μm, and the thickness of the bottom layer aluminum sheet is 100-200 μm. The utility model has the advantages of the lithium aluminum alloy negative pole preparation is quick, the cycle performance is good, be fit for automatic mass production.

Description

Novel rechargeable lithium-manganese button cell

Technical Field

The utility model relates to a novel can charge lithium manganese button cell, concretely relates to can charge lithium manganese button cell's lithium aluminum alloy negative pole belongs to chemical power source energy storage technical field.

Background

Due to the popularization and rapid development of electronic products, the demand of rechargeable lithium/manganese dioxide button batteries is increasing, and the manufacturing speed of lithium-aluminum alloy cathodes is very low in the production process of the existing rechargeable lithium/manganese dioxide batteries, so that the great increase of the battery yield is limited.

The conventional lithium-aluminum alloy cathode generally adopts a method similar to that disclosed in a patent (CN 87100735), namely, a lithium-aluminum alloy coating is prepared by a co-rolling process at normal temperature: in an environment with relative humidity lower than 1%, commercial pure aluminum or aluminum alloy without lithium is rolled together with metallic lithium, and a lithium aluminum alloy coating is formed on the surface of the aluminum after being pressed and kept for 24 hours.

The invention patent (ZL 201510818761.2) and the invention patent (ZL 201510818762.7) disclose a method for manufacturing a lithium-aluminum alloy negative electrode of a 3V rechargeable button type lithium battery. In this method, since the aluminum sheet has a relatively large thickness, there is a problem that the alloy phase generated in forming the lithium-aluminum alloy is not uniform.

The invention patent (publication No. CN110364686A, published: 2019.10.22) discloses a method for manufacturing a negative electrode of a rechargeable button lithium-manganese battery, which is obtained by soaking an electrolyte under high pressure (300-1000 kgf) for a long time (16-24 h).

The utility model discloses a novel rechargeable lithium manganese button cell, its lithium aluminum alloy negative pole have the preparation fast, the cycling performance better, be fit for automatic mass production's advantage.

SUMMERY OF THE UTILITY MODEL

The to-be-solved technical problem of the utility model is to provide a rechargeable lithium manganese button cell that can quick batch production and performance are excellent.

In order to solve the above problems, the utility model discloses a realize through following technical scheme: the novel rechargeable lithium-manganese button cell is composed of a negative electrode shell, a negative electrode, a diaphragm, electrolyte, a positive electrode and a positive electrode shell, and is characterized in that the negative electrode is formed by compounding a bottom layer aluminum sheet/lithium sheet/an upper layer aluminum sheet layer under the pressure of 10-70 MPa for 5-10 minutes.

Preferably, the molar ratio of lithium to aluminum (bottom layer + upper layer) is (5-8): 10.

preferably, the aluminum sheet is an embossed aluminum sheet with the purity of 99%, and the thickness of the upper aluminum sheet is as follows: thickness of the bottom aluminum sheet = 1: (2-3).

Preferably, the thickness of the upper layer aluminum sheet (in contact with the separator) is 50-100 μm, and the thickness of the bottom layer aluminum sheet (in contact with the negative electrode shell) is 100-200 μm.

The preparation steps of the composite cathode of the utility model are as follows: (1) selecting an embossed aluminum sheet with proper thickness, punching a wafer with a required size, and deoiling, cleaning and drying the wafer for later use; (2) and sequentially putting the bottom-layer aluminum sheet, the lithium sheet and the upper-layer aluminum sheet into a die in an environment with the relative humidity lower than 1%, pressurizing by 10-70 MPa, and taking out after 5-10 minutes to obtain the composite cathode.

Assembling the battery: and in an environment with the relative humidity lower than 1%, sequentially placing a composite negative electrode and a diaphragm on the negative electrode shell, dripping electrolyte, then placing the positive electrode, covering the positive electrode shell, and sealing to obtain the rechargeable lithium manganese button cell.

Compared with the prior art, the beneficial effects of the utility model are that:

(1) because the negative pole adopts a structure formed by compounding a bottom layer aluminum sheet/a lithium sheet/an upper layer aluminum sheet, the thicknesses of the two layers of aluminum sheets are different, the upper layer aluminum sheet is thinner, the bottom layer aluminum sheet is thicker, the upper layer quickly forms uniform lithium aluminum alloy under certain pressure, the bottom layer is slower, the whole negative pole composite layer forms graded distribution alloying from top to bottom, the alloying of the surface opposite to the positive pole is more complete, the conductivity of the surface in contact with the negative pole shell is better, the structure of the negative pole is more stable, and a material foundation is laid for prolonging the cycle life of the battery; the embossing on the surface of the aluminum sheet increases the contact area of the lithium sheet and the aluminum sheet, so that the alloying reaction is carried out more quickly and completely, and the phenomenon of alloy layering is avoided. The structural integrity can be still maintained after multiple charge-discharge cycles, and the pulverization phenomenon of the traditional cathode is avoided, so that the internal resistance of the cathode is reduced, the polarization during discharge is reduced, and the cycle performance of the battery is better. The cycle times are more than 500 times when the cycle is carried out at 0.1C and 10% of charging and discharging depth.

(2) Because the negative electrode adopts a structure formed by compounding a bottom layer aluminum sheet/a lithium sheet/an upper layer aluminum sheet, the thickness of the aluminum sheet is reduced, the alloying time is shorter, the operation is simple and convenient, the production efficiency is high, and the method is suitable for automatic mass production.

Drawings

Fig. 1 is a schematic structural diagram of a lithium manganese button cell of the present invention.

Fig. 2 is a schematic diagram of the preparation process of the lithium aluminum alloy cathode of the present invention.

In the figure: 1, a negative electrode shell; 2, compounding a negative electrode; 3, a diaphragm; 4, a positive electrode; 5, a positive electrode shell; 6, coating an aluminum sheet; 7 lithium sheets; 8 bottom layer aluminum sheet.

Fig. 3 shows the cycle life curve of the button li-mn cell of the present invention.

Detailed Description

The present invention is further illustrated by the following examples, which are intended to be illustrative, not limiting and are not intended to limit the scope of the invention.

Example 1

The following describes the specific implementation process of the present invention with reference to the drawings.

In this example, a CR1220 battery was produced.

Preparation of a negative electrode:

(1) respectively punishing a 9mm round piece on an embossed aluminum material with the purity of 99 percent, the thickness of 80 mu m and the thickness of 170 mu m;

(2) after the aluminum wafer is deoiled and cleaned, the aluminum wafer is blown and dried for more than 12 hours at 105 ℃;

(3) in a glove box with relative humidity lower than 1%, 170 μm aluminum wafers 8 of 9mm, 220 μm lithium wafers 7 and 80 μm aluminum wafers 6 are put into a mold in sequence, 30 MPa pressure is applied, the pressure is removed after 10 minutes of holding, and the composite negative electrode 2 is obtained after taking out.

The positive electrode is a positive plate made of chargeable lithium manganese oxide, conductive agent and adhesive.

Assembling the battery: in a glove box with relative humidity lower than 1%, a composite cathode 2 and a PP diaphragm 3 with the diameter of 30 mu M are sequentially put on a cathode shell 1, and 3-5 drops of 1M LiPF are dropped₆And (EC: DEC: PC, mass ratio of 1: 1: 0.5) electrolyte, then placing the anode 4, covering the anode shell 5, and sealing to obtain the CR1220 button cell.

The lithium manganese button cell of example 1 above was tested for performance:

the test method comprises the following steps: the cell was cycled at 0.1C, 10% DOD, charged at a voltage of 3.25V, and discharged to 2.0V, at end of life. The cycle number of the battery reaches more than 508, and the discharge cut-off voltage and the cycle number curve are shown in figure 3.

It should be noted that, the purpose of the aluminum sheet embossed in the present invention is to increase the contact area between the aluminum sheet and the lithium sheet, and the specific embossed pattern is not limited.

Although the invention has been described in detail in this specification with reference to specific embodiments and illustrative embodiments, it will be apparent to those skilled in the art that certain changes and modifications can be made therein without departing from the scope of the invention. Therefore, such modifications and improvements are intended to be within the scope of the invention as claimed.

Claims

1. The utility model provides a novel rechargeable lithium manganese button cell, includes anodal shell, anodal, diaphragm, negative pole shell, electrolyte, its characterized in that: the negative pole includes bottom aluminum sheet/lithium piece/upper aluminum sheet three-layer, and upper aluminum sheet contacts with the diaphragm, and upper aluminum sheet thickness: thickness of the bottom aluminum sheet = 1: (2-3).

2. The new rechargeable lithium manganese button cell as claimed in claim 1, wherein: the thickness of the upper layer aluminum sheet in the negative electrode is 50-100 mu m, and the thickness of the bottom layer aluminum sheet is 100-200 mu m.