A lithium-ion battery with a silicon-containing negative electrode

Abstract

The present invention discloses a lithium-ion battery with a silicon-containing negative electrode, which includes a positive electrode sheet and a negative electrode sheet. The active material of the negative electrode sheet is a composite material of silicon oxide, negative electrode graphite, single-walled carbon nanotubes, conductive carbon black, and graphene oxide. In the negative electrode material, the mass ratio of the negative electrode active material: CMC: SBR is 96.8-97.8: 0.8-1.6: 1-2. The lithium-ion battery with a silicon-containing negative electrode of the present invention has the characteristics of small volume effect, excellent rate performance, and good cycle performance.

Description

Technical Field

[0001] The present invention relates to the technical field of lithium ion batteries, and in particular to a lithium ion battery containing a silicon negative electrode. Background Art

[0002] With the development of the new energy industry, lithium-ion batteries have higher and higher requirements for energy density. How to make full use of the space within a limited volume to obtain a larger capacity while ensuring its rate performance and cycle performance has become the focus and difficulty of the industry's development. Compared with graphite negative electrodes, silicon negative electrodes have the characteristics of high theoretical specific capacity and have certain application prospects. However, silicon negative electrodes have the characteristics of large changes in volume effect. As the cycle progresses, the volume collapses and pulverizes severely, which directly limits its promotion and application. Summary of the invention

[0003] The purpose of the present invention is to provide a lithium ion battery containing a silicon negative electrode, which has the characteristics of small volume effect, excellent rate performance and good cycle performance.

[0004] The present invention can be implemented by the following technical solutions:

[0005] The invention discloses a lithium ion battery containing a silicon negative electrode, comprising a positive electrode sheet and a negative electrode sheet. The active material of the negative electrode sheet is a composite material of silicon oxide, negative electrode graphite, single-walled carbon tube, conductive carbon black and graphene oxide. The composite mass ratio of the active material is: silicon oxide: negative electrode graphite: single-walled carbon tube: conductive carbon black: graphene oxide = 5:93:0.3:0.5:0.2. The mass ratio of negative electrode active material: CMC: SBR in the negative electrode material is 96.8-97.8:0.8-1.6:1-2.

[0006] Furthermore, the preparation process of the negative electrode slurry of the negative electrode sheet includes the following steps:

[0007] S10, preparation of mother dispersion: dispersing single-walled carbon tubes, graphene oxide, and conductive carbon black in CMC aqueous solution, revolving at 20-40 Hz, rotating at 20-40 Hz, and stirring for 25-35 min to mix them evenly to obtain mother dispersion;

[0008] S11 Preparation of silicon-containing dispersion: Add silicon oxide to the dispersion obtained in S10, revolve at 20-40 Hz, rotate at 20-40 Hz, and stir for 25-35 minutes to mix evenly to obtain a silicon-containing dispersion:

[0009] S12. Preparation of negative electrode slurry: Disperse negative electrode graphite evenly in the SBR aqueous solution, add the silicon-containing dispersion obtained in S11, adjust the viscosity, and mix them evenly to obtain negative electrode slurry.

[0010] Furthermore, the preparation of the lithium-ion battery also includes the following steps:

[0011] S20, Electrode Coating and Electrode Fabrication: Coat the positive and negative electrodes respectively and slit them according to the designed dimensions to obtain positive and negative electrode sheets;

[0012] S30, Winding Assembly: Take the positive and negative electrode sheets obtained in step S20 and wind them manually or by machine to obtain a bare battery cell with a separator isolating the positive and negative electrode sheets;

[0013] S40, Injection and Formation: Put the bare battery cell obtained in step S30 into a casing, inject electrolyte, and perform formation in a charge and discharge cabinet after encapsulation to obtain a lithium-ion battery;

[0014] S50, Secondary Encapsulation and Capacity Grading: After discharging the gas generated during formation from the lithium-ion battery that has completed the injection and formation in step S40, perform secondary encapsulation and capacity grading in a charge and discharge cabinet to obtain a lithium-ion battery that meets the capacity requirements.

[0015] Furthermore, the casing for encapsulating the lithium-ion battery is an aluminum-plastic film or an aluminum shell.

[0016] Furthermore, the positive active material of the positive electrode sheet is a lithium iron phosphate material, a lithium manganate material, a lithium cobaltate material, or a lithium nickel cobalt manganese ternary material.

[0017] Furthermore, the negative electrode graphite is artificial graphite, natural graphite, or mesocarbon microbeads.

[0018] Furthermore, the current collector of the positive electrode sheet is copper foil, and the current collector of the negative electrode sheet is aluminum foil.

[0019] Furthermore, the separator is a dry separator or a wet separator.

[0020] Furthermore, the separator is a PP separator, a PE separator, or a PP / PE composite separator.

[0021] Furthermore, the mass ratio of the positive active material: CNT:PVDF in the positive electrode sheet is 98 - 99.4:0.4 - 0.6:0.6 - 1.

[0022] The lithium-ion battery with a silicon-containing negative electrode of the present invention has the following beneficial effects:

[0023] The lithium-ion battery of the present invention uses single-walled carbon nanotubes and graphene to coat silicon oxide, improving the conductivity of silicon oxide, reducing the cyclic expansion coefficient of the silicon negative electrode material, and increasing the cycle life of the lithium-ion battery. The structures of single-walled carbon nanotubes and graphene are very stable, and the connection between the internal carbon atoms is flexible. When an external force is applied, the carbon atom plane will bend and deform, so that the carbon atoms do not have to rearrange to adapt to the external force, thus maintaining the structural stability, which can effectively alleviate the volume effect of the silicon material during charge and discharge and maintain a good three-dimensional structure and conductive network. Detailed Implementation Modes

[0024] To enable those skilled in the art to better understand the technical solutions of the present invention, the products of the present invention will be further described in detail below in conjunction with embodiments.

[0025] The present invention discloses a lithium-ion battery with a silicon-containing negative electrode, including a positive electrode sheet and a negative electrode sheet. The active material of the negative electrode sheet is a composite material of silicon oxide, negative electrode graphite, single-walled carbon nanotubes, conductive carbon black, and graphene oxide. The composite mass ratio in the active material is: silicon oxide: negative electrode graphite: single-walled carbon nanotubes: conductive carbon black: graphene oxide = 5:93:0.3:0.5:0.2. The mass ratio of the negative electrode active material: CMC: SBR in the negative electrode material is 96.8 - 97.8:0.8 - 1.6:1 - 2.

[0026] Furthermore, the preparation process of the negative electrode slurry of the negative electrode sheet includes the following steps:

[0027] S10. Preparation of the master dispersion: Disperse single-walled carbon nanotubes, graphene oxide, and conductive carbon black in an aqueous CMC solution, with a revolution speed of 20 - 40 Hz, a rotation speed of 20 - 40 Hz, and stir for 25 - 35 min to make them evenly mixed to obtain the master dispersion, with a viscosity of 3000 CP - 4500 CP;

[0028] S11. Preparation of the silicon-containing dispersion: Add silicon oxide to the dispersion obtained in S10, with a revolution speed of 20 - 40 Hz, a rotation speed of 20 - 40 Hz, and stir for 25 - 35 min to make them evenly mixed to obtain the silicon-containing dispersion, with a viscosity of 3500 CP - 5000 CP;

[0029] S12. Preparation of the negative electrode slurry: Evenly disperse the negative electrode graphite in an aqueous SBR solution, add the silicon-containing dispersion obtained in S11, adjust its viscosity, and make them evenly mixed to obtain the negative electrode slurry, with a viscosity of 2500 CP - 4500 CP.

[0030] Furthermore, the production of the lithium-ion battery also includes the following steps:

[0031] S20. Electrode coating and electrode production: Coat the positive electrode and the negative electrode respectively and cut them into strips according to the designed size to obtain the positive electrode sheet and the negative electrode sheet;

[0032] S30. Winding assembly: Take the positive electrode sheet and the negative electrode sheet obtained in step S20 and wind them manually or by machine to obtain a bare battery cell with a separator isolated between the positive electrode sheet and the negative electrode sheet;

[0033] S40. Injection and formation: Put the bare battery cell obtained in step S30 into a housing, inject electrolyte, and after encapsulation, perform formation in a charge and discharge cabinet to obtain the lithium-ion battery;

[0034] S50. Secondary encapsulation and formation: After discharging the gas generated during formation from the lithium-ion battery that has completed the liquefaction injection in step S40, it is secondarily encapsulated and then subjected to formation in a charge and discharge cabinet to obtain a lithium-ion battery that meets the capacity requirements.

[0035] Further, the outer shell for encapsulating the lithium-ion battery is an aluminum-plastic film or an aluminum shell.

[0036] Further, the positive electrode active material of the positive electrode plate is a lithium iron phosphate material, a lithium manganate material, a lithium cobaltate material, or a lithium nickel cobalt manganese ternary material.

[0037] Further, the negative electrode graphite is artificial graphite, natural graphite, or mesocarbon microbeads.

[0038] Further, the current collector of the positive electrode plate is copper foil, and the current collector of the negative electrode plate is aluminum foil.

[0039] Further, the separator is a dry separator or a wet separator.

[0040] Further, the separator is a PP separator, a PE separator, or a PP / PE composite separator.

[0041] Further, the mass ratio of the positive electrode active material: CNT: PVDF in the positive electrode plate is 98 - 99.4: 0.4 - 0.6: 0.6 - 1.

[0042] Example 1

[0043] The present invention discloses a lithium-ion battery with a silicon-containing negative electrode, including a positive electrode plate and a negative electrode plate. The active material of the negative electrode plate is a composite material of silicon oxide, negative electrode graphite, single-walled carbon nanotubes, conductive carbon black, and graphene oxide. The composite mass ratio in the active material is: silicon oxide: negative electrode graphite: single-walled carbon nanotubes: conductive carbon black: graphene oxide = 5: 93: 0.3: 0.5: 0.2. The mass ratio of the negative electrode active material: CMC: SBR in the negative electrode material is 97.8: 1.2: 1.

[0044] The lithium-ion battery of the present invention is prepared by the following method:

[0045] S10. Preparation of the mother dispersion: Disperse single-walled carbon nanotubes, graphene oxide, and conductive carbon black in an aqueous CMC solution, with a revolution speed of 40 Hz, a rotation speed of 30 Hz, and stir for 25 minutes to make them evenly mixed to obtain the mother dispersion;

[0046] S11. Preparation of the silicon-containing dispersion: Add silicon oxide to the dispersion obtained in S10, with a revolution speed of 20 - 40 Hz, a rotation speed of 40 Hz, and stir for 30 minutes to make them evenly mixed to obtain the silicon-containing dispersion:

[0047] S12. Preparation of negative electrode paste: Evenly disperse negative electrode graphite in an SBR aqueous solution, add the silicon-containing dispersion obtained in S11, adjust its viscosity, and mix evenly to obtain the negative electrode paste;

[0048] S20. Electrode coating and electrode production: Coat the positive electrode and the negative electrode respectively and cut them into strips according to the designed size to obtain the positive electrode sheet and the negative electrode sheet;

[0049] S30. Winding assembly: Take the positive electrode sheet and the negative electrode sheet obtained in step S20 and wind them manually or by machine to obtain a bare battery cell with a separator isolated between the positive electrode sheet and the negative electrode sheet;

[0050] S40. Injection and formation: Put the bare battery cell obtained in step S30 into a housing, inject electrolyte, and perform formation in a charge and discharge cabinet after encapsulation to obtain a lithium-ion battery;

[0051] S50. Secondary encapsulation and grading: After discharging the gas generated during formation from the lithium-ion battery that has completed the injection and formation in step S40, perform secondary encapsulation and grading in a charge and discharge cabinet to obtain a lithium-ion battery that meets the capacity requirements.

[0052] In terms of the selection of the housing material, the housing for the lithium-ion battery encapsulation is an aluminum-plastic film.

[0053] In terms of the material selection, the positive electrode active material of the positive electrode sheet is a lithium iron phosphate material; specifically, the mass ratio of the positive electrode active material: CNT:PVDF is 99.4:0.5:0.6; the negative electrode graphite is artificial graphite; the current collector of the positive electrode sheet is copper foil, and the current collector of the negative electrode sheet is aluminum foil.

[0054] In terms of the selection of the separator, the separator is a dry-process separator; specifically, the separator is a PP separator.

[0055] Example 2

[0056] The present invention discloses a lithium-ion battery with a silicon-containing negative electrode, including a positive electrode sheet and a negative electrode sheet. The active material of the negative electrode sheet is a composite material of silicon oxide, negative electrode graphite, single-walled carbon nanotubes, conductive carbon black, and graphene oxide. The composite mass ratio in the active material is: silicon oxide: negative electrode graphite: single-walled carbon nanotubes: conductive carbon black: graphene oxide = 5:93:0.3:0.5:0.2. The mass ratio of the negative electrode active material: CMC: SBR in the negative electrode material is 97.3:0.8:2.

[0057] The lithium-ion battery of the present invention is prepared by the following method:

[0058] S10. Preparation of mother dispersion: Disperse single-walled carbon nanotubes, graphene oxide, and conductive carbon black in a CMC aqueous solution, with a revolution speed of 30 Hz, a rotation speed of 20 Hz, and stir for 35 min to mix evenly to obtain the mother dispersion;

[0059] S11 Preparation of silicon-containing dispersion: Add silicon oxide to the dispersion obtained in S10, revolve at 20-40 Hz, rotate at 30 Hz, and stir for 25 minutes to mix evenly to obtain a silicon-containing dispersion:

[0060] S12, preparation of negative electrode slurry: evenly disperse the negative electrode graphite in the SBR aqueous solution, add the silicon-containing dispersion obtained in S11, adjust the viscosity, and mix them evenly to obtain the negative electrode slurry;

[0061] S20, electrode coating and electrode production: coating the positive electrode and the negative electrode respectively and slitting them according to the designed size to obtain positive electrode sheets and negative electrode sheets;

[0062] S30, winding assembly: taking the positive electrode sheet and the negative electrode sheet obtained in step S20 and winding them manually or by machine to obtain a bare cell with a separator separating the positive electrode sheet and the negative electrode sheet;

[0063] S40, liquid injection and formation: the bare battery cell obtained in step S30 is placed in a housing, an electrolyte is injected, and after packaging, the battery is formed in a charge and discharge cabinet to obtain a lithium-ion battery;

[0064] S50, secondary sealing and capacity division: after the lithium-ion battery formed by the liquid injection in step S40 is discharged, the gas generated by the formation is secondary sealed in a charge and discharge cabinet for capacity division to obtain a lithium-ion battery that meets the capacity requirements.

[0065] In terms of the choice of shell material, the shell of the lithium-ion battery package is an aluminum shell.

[0066] In terms of material selection, the positive electrode active material of the positive electrode sheet is lithium manganese oxide material; specifically, the mass ratio of positive electrode active material: CNT:PVDF is 98.7:0.4:1; the negative electrode graphite is natural graphite; the current collector of the positive electrode sheet is copper foil, and the current collector of the negative electrode sheet is aluminum foil.

[0067] In terms of the selection of the diaphragm, the diaphragm is a dry-process diaphragm, specifically, the diaphragm is a PP / PE composite diaphragm.

[0068] Example 3

[0069] The invention discloses a lithium ion battery containing a silicon negative electrode, comprising a positive electrode sheet and a negative electrode sheet. The active material of the negative electrode sheet is a composite material of silicon oxide, negative electrode graphite, single-walled carbon tube, conductive carbon black and graphene oxide. The composite mass ratio of the active material is: silicon oxide: negative electrode graphite: single-walled carbon tube: conductive carbon black: graphene oxide = 5:93:0.3:0.5:0.2. The mass ratio of negative electrode active material: CMC: SBR in the negative electrode material is 96.8:0.8:1.5.

[0070] The lithium ion battery of the present invention is prepared by the following method:

[0071] S10. Preparation of the mother dispersion: Disperse single-walled carbon nanotubes, graphene oxide, and conductive carbon black in an aqueous CMC solution, with a revolution speed of 20 Hz and a rotation speed of 30 Hz, and stir for 30 min to obtain a uniformly mixed mother dispersion.

[0072] S11. Preparation of the silicon-containing dispersion: Add silicon oxide to the dispersion obtained in S10, with a revolution speed of 20 - 40 Hz and a rotation speed of 20 Hz, and stir for 35 min to obtain a uniformly mixed silicon-containing dispersion.

[0073] S12. Preparation of the negative electrode slurry: Uniformly disperse negative electrode graphite in an aqueous SBR solution, add the silicon-containing dispersion obtained in S11, adjust its viscosity, and stir to obtain a uniformly mixed negative electrode slurry.

[0074] S20. Electrode coating and electrode production: Coat the positive electrode and the negative electrode respectively and cut them into strips according to the designed size to obtain a positive electrode sheet and a negative electrode sheet.

[0075] S30. Winding assembly: Take the positive electrode sheet and the negative electrode sheet obtained in step S20 and wind them manually or by machine to obtain a bare battery cell with a separator isolating the positive electrode sheet and the negative electrode sheet.

[0076] S40. Injection and formation: Place the bare battery cell obtained in step S30 into a casing, inject electrolyte, and after encapsulation, perform formation in a charge and discharge cabinet to obtain a lithium-ion battery.

[0077] S50. Secondary encapsulation and grading: After discharging the gas generated during formation from the lithium-ion battery that has completed step S40 of injection and formation, perform secondary encapsulation and grading in a charge and discharge cabinet to obtain a lithium-ion battery that meets the capacity requirements.

[0078] In terms of the selection of the casing material, the casing for the lithium-ion battery encapsulation is an aluminum-plastic film or an aluminum shell.

[0079] In terms of the material selection, the positive electrode active material of the positive electrode sheet is a nickel-cobalt-manganese-lithium ternary material; specifically, the mass ratio of the positive electrode active material: CNT:PVDF is 98:0.6:0.8; the negative electrode graphite is mesocarbon microbeads; the current collector of the positive electrode sheet is copper foil, and the current collector of the negative electrode sheet is aluminum foil.

[0080] In terms of the selection of the separator, the separator is a wet separator; specifically, the separator is a PP separator.

[0081] Example 4

[0082] The present invention discloses a lithium-ion battery with a silicon-containing negative electrode, which includes a positive electrode sheet and a negative electrode sheet. The active material of the negative electrode sheet is a composite material of silicon oxide, negative electrode graphite, single-walled carbon nanotubes, conductive carbon black, and graphene oxide. The composite mass ratio in the active material is: silicon oxide: negative electrode graphite: single-walled carbon nanotubes: conductive carbon black: graphene oxide = 5:93:0.3:0.5:0.2. The mass ratio of the negative electrode active material: CMC: SBR in the negative electrode material is 97.3:1.2:1.5.

[0083] The lithium-ion battery of the present invention is prepared by the following method:

[0084] S10. Preparation of the mother dispersion: Disperse single-walled carbon nanotubes, graphene oxide, and conductive carbon black in an aqueous CMC solution, with a revolution speed of 30 Hz, a rotation speed of 30 Hz, and stir for 30 minutes to make them evenly mixed to obtain the mother dispersion;

[0085] S11. Preparation of the silicon-containing dispersion: Add silicon oxide to the dispersion obtained in S10, with a revolution speed of 20 - 40 Hz, a rotation speed of 30 Hz, and stir for 30 minutes to make them evenly mixed to obtain the silicon-containing dispersion;

[0086] S12. Preparation of the negative electrode paste: Uniformly disperse the negative electrode graphite in an aqueous SBR solution, add the silicon-containing dispersion obtained in S11, adjust its viscosity, and make them evenly mixed to obtain the negative electrode paste;

[0087] S20. Electrode coating and electrode production: Coat the positive electrode and the negative electrode respectively and cut them into strips according to the designed size to obtain the positive electrode sheet and the negative electrode sheet;

[0088] S30. Winding assembly: Take the positive electrode sheet and the negative electrode sheet obtained in step S20 and wind them by machine to obtain a bare battery cell with a separator isolated between the positive electrode sheet and the negative electrode sheet;

[0089] S40. Injection and formation: Put the bare battery cell obtained in step S30 into a casing, inject electrolyte, and after encapsulation, perform formation in a charge and discharge cabinet to obtain the lithium-ion battery;

[0090] S50. Secondary sealing and grading: After discharging the gas generated during formation from the lithium-ion battery that has completed the injection and formation in step S40, perform secondary encapsulation and grading in a charge and discharge cabinet to obtain the lithium-ion battery that meets the capacity requirements.

[0091] In terms of the selection of the casing material, the casing for the lithium-ion battery encapsulation is an aluminum-plastic film or an aluminum shell.

[0092] In terms of the material selection, the positive electrode active material of the positive electrode sheet is a lithium cobalt oxide material; specifically, the mass ratio of the positive electrode active material: CNT: PVDF is 98.7:0.5:0.8; the negative electrode graphite is artificial graphite; the current collector of the positive electrode sheet is a copper foil, and the current collector of the negative electrode sheet is an aluminum foil.

[0093] In the selection of the separator, the separator is a wet-process separator. Specifically, the separator is a PE separator.

[0094] Application Example 1

[0095] Using the method of Example 4, a 486397-5500MAH soft-pack polymer lithium-ion battery was prepared and subjected to subsequent performance tests.

[0096] Comparative Example 1

[0097] The main difference between Comparative Example 1 and Application Example 1 is that silicon oxide is not added to the active material of the negative electrode sheet, and its mass ratio is replaced by artificial graphite. A 486397-5500MAH soft-pack polymer lithium-ion battery was prepared and subjected to subsequent performance tests.

[0098] Comparative Example 2

[0099] The main difference between Comparative Example 2 and Application Example 1 is that single-walled carbon nanotubes are not added to the active material of the negative electrode sheet, and its mass ratio is replaced by artificial graphite. A 486397-5500MAH soft-pack polymer lithium-ion battery was prepared and subjected to subsequent performance tests.

[0100] In order to verify the technical effects of the present invention, electrical performance tests were respectively carried out on Application Example 1, Comparative Example 1, and Application Example 2, and the test results are as follows:

[0101] Table 1 Performance Test Results

[0102]

[0103] The above embodiments are only specific embodiments of the present invention, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the present invention patent. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can be made, and these obvious replacement forms all belong to the protection scope of the present invention.

Claims

1. A lithium-ion battery with a silicon-containing negative electrode, comprising a positive electrode sheet and a negative electrode sheet, characterized in that: The active material of the negative electrode sheet is a composite material of silicon oxide, negative electrode graphite, single-walled carbon nanotubes, conductive carbon black, and graphene oxide. The composite mass ratio in the active material is: silicon oxide: negative electrode graphite: single-walled carbon nanotubes: conductive carbon black: graphene oxide = 5:93:0.3:0.5:0.

2. The mass ratio of the negative electrode active material: CMC: SBR in the negative electrode material is 96.8 - 97.8:0.8 - 1.6:1 - 2; The preparation process of the negative electrode slurry of the negative electrode sheet includes the following steps: S10. Preparation of the mother dispersion: Disperse single-walled carbon nanotubes, graphene oxide, and conductive carbon black in an aqueous CMC solution, with a revolution speed of 20 - 40 Hz and a rotation speed of 20 - 40 Hz, and stir for 25 - 35 min to make them evenly mixed to obtain the mother dispersion; S11. Preparation of the silicon-containing dispersion: Add silicon oxide to the dispersion obtained in S10, with a revolution speed of 20 - 40 Hz and a rotation speed of 20 - 40 Hz, and stir for 25 - 35 min to make them evenly mixed to obtain the silicon-containing dispersion; S12. Preparation of the negative electrode slurry: Uniformly disperse the negative electrode graphite in an aqueous SBR solution, add the silicon-containing dispersion obtained in S11, adjust its viscosity, and make them evenly mixed to obtain the negative electrode slurry; The production of the lithium-ion battery further includes the following steps: S20. Electrode coating and electrode production: Coating is carried out on the positive electrode and the negative electrode respectively, and slitting is carried out according to the designed size to obtain a positive electrode sheet and a negative electrode sheet; S30. Winding assembly: Take the positive electrode sheet and the negative electrode sheet obtained in step S20, and wind them manually or by machine to obtain a bare battery cell with a separator isolated between the positive electrode sheet and the negative electrode sheet; S40. Injection and formation: Put the bare battery cell obtained in step S30 into a casing, inject electrolyte, and after encapsulation, carry out formation in a charge and discharge cabinet to obtain a lithium-ion battery; S50. Secondary encapsulation and grading: After discharging the gas generated during formation from the lithium-ion battery that has completed step S40 of injection and formation, carry out secondary encapsulation and grading in a charge and discharge cabinet to obtain a lithium-ion battery that meets the capacity requirements.

2. The lithium-ion battery with a silicon-containing negative electrode according to claim 1, wherein: The casing for packaging the lithium-ion battery is an aluminum-plastic film or an aluminum shell.

3. The lithium-ion battery with a silicon-containing negative electrode according to claim 2, characterized in that: The positive electrode active material of the positive electrode sheet is a lithium iron phosphate material, a lithium manganate material, a lithium cobaltate material, or a lithium nickel cobalt manganese ternary material.

4. The lithium-ion battery with a silicon-containing negative electrode according to claim 3, characterized in that: The negative electrode graphite is artificial graphite, natural graphite, or mesophase carbon microspheres.

5. The lithium-ion battery with a silicon-containing negative electrode according to claim 4, characterized in that: The current collector of the positive electrode sheet is copper foil, and the current collector of the negative electrode sheet is aluminum foil.

6. The lithium ion battery with a silicon-containing negative electrode according to claim 5, characterized in that: The separator is a dry separator or a wet separator.

7. The lithium-ion battery with a silicon-containing negative electrode according to claim 6, characterized in that: The separator is a PP separator, a PE separator, or a PP / PE composite separator.

8. The lithium-ion battery with a silicon-containing negative electrode according to claim 7, characterized in that: The mass ratio of the positive electrode active material: CNT: PVDF in the positive electrode sheet is 98 - 99.4: 0.4 - 0.6: 0.6 - 1.

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