Fast-charging cell, lithium-ion battery, and electric product

Abstract

A fast-charging cell, a lithium-ion battery, and an electric product, which relate to the technical field of new energy. In the provided fast-charging cell, a positive electrode coating notch is disposed on a positive electrode and a negative electrode coating notch is disposed on a negative electrode. By means of optimizing the arrangement positions of the positive electrode coating notch and the negative electrode coating notch, the lithium-ion acceptance capability of the negative electrode is improved, the increase amplitude of side reactions is minimized, and the stress at a corner is alleviated, thereby ultimately enhancing the rate performance and cycling performance of the fast-charging cell. Further provided are a lithium-ion battery comprising the fast-charging cell, and an electric product.

Description

A fast-charging cell, a lithium ion battery and an electric product TECHNICAL FIELD

[0001] The present application relates to the technical field of new energy, in particular to a fast-charging cell, a lithium ion battery and an electric product. BACKGROUND

[0002] Lithium ion batteries are widely used in the digital field and the power battery field due to high energy density. As the requirements for energy density and fast-charging rate of digital products and power batteries are increasingly high, the surface density and the compaction density of the lithium ion battery cell are made higher and higher, which leads to that the corner part needs to bear more and more pressure in the process of charging and discharging. With the compression of the pressure, the electrolyte at the corner is gradually squeezed out, and finally leads to the broken bridge at the corner.

[0003] The lithium precipitation at the corner of the cell starts from the inner layer and gradually spreads to the outer layer. Taking the middle tab structure as an example, the lithium precipitation at the corner of the anode corresponding to the cathode tab is the most serious, and then gradually becomes less and less, and generally gradually increases with the increase of the cycle number until the whole tab is diffused.

[0004] With the use of silicon-based negative electrode material in the battery, the lithium precipitation at the corner of the lithium ion battery cell becomes more and more serious, and the time of occurrence becomes earlier and earlier, which has a certain relationship with the fast consumption of the electrolyte of the silicon system. Moreover, research shows that the method of using laser to punch holes on the negative electrode tab to improve the electrolyte retention capacity will lead to the destruction of the structure of the silicon-based negative electrode material, the exposure of high-activity substances, the increase of side reactions, the acceleration of the consumption of electrolyte, and the excessive expansion of the volume of the negative electrode, which leads to more pressure at the corner and aggravates the lithium precipitation at the corner. That is to say, although the conventional lithium ion battery cell also has the problem of lithium precipitation at the corner, the fast-charging cell containing the silicon-based negative electrode material is more serious. Moreover, the conventional punching method is difficult to alleviate and may deteriorate the performance.

[0005] In summary, the problem of lithium precipitation at the corner of the silicon system fast-charging cell is serious, and the solutions provided in the related art have very limited effect.

[0006] SUMMARY

[0007] The present application aims to at least solve one of the technical problems existing in the prior art. To this end, the present application provides a fast-charging cell, which improves the fast-charging performance of the high-energy-density cell.

[0008] The present application also provides a lithium ion battery prepared from the raw materials including the fast-charging cell.

[0009] The present application also provides an electric product prepared from the raw materials including the fast-charging cell.

[0010] According to the fast charging battery cell of the first aspect of the present application, the positive electrode, the separator and the negative electrode are wound together; the separator is arranged between the positive electrode and the negative electrode; the negative electrode comprises a negative electrode current collector, a negative electrode coating arranged on the surface of the negative electrode current collector, and a middle negative electrode tab electrically connected to the negative electrode current collector; the positive electrode comprises a positive electrode current collector, a positive electrode coating arranged on the surface of the positive electrode current collector, and a middle positive electrode tab electrically connected to the positive electrode current collector;

[0011] From the positive electrode tab, a positive electrode coating notch is arranged on the positive electrode coating at the corner of the fast charging battery cell;

[0012] Around the projection position of the positive electrode tab on the negative electrode, a negative electrode coating notch is arranged on the negative electrode coating.

[0013] According to the fast charging battery cell of the present application, at least the following beneficial effects are achieved:

[0014] The fast charging battery cell provided by the present application adopts a design of local punching of the positive electrode and the negative electrode, and realizes accurate control of dynamics.

[0015] For the fast charging battery cell with the middle tab, the current density is the largest near the positive electrode tab or the projection position of the positive electrode tab on the negative electrode surface during the charging stage. Therefore, the positive electrode coating notch of the present application is arranged around the positive electrode tab, and the negative electrode coating notch is arranged around the projection position of the positive electrode tab on the negative electrode surface, which can effectively solve the problem of insufficient charging and improve the fast charging performance.

[0016] For the wound type fast charging battery cell, if the negative electrode has poor lithium ion acceptance ability, lithium precipitation will occur. During charging, the entire surface of the negative electrode accepts lithium ions, and the lithium ion acceptance ability of the entire surface needs to be improved. Therefore, the negative electrode coating notch is arranged around the projection position of the positive electrode tab on the negative electrode surface. The corner is the extrusion and electrolyte consumption of long cycle, so the positive electrode coating notch is arranged only around the positive electrode tab at the corner.

[0017] As can be seen from the above description, the scheme provided by the present application sets the positive electrode coating notch or the negative electrode coating notch as little as possible on the basis of ensuring the charging performance.

[0018] According to some embodiments of the present application, the total number of winding layers N of the fast charging battery cell ranges from 10 to 50. For example, it can be 11 layers, 12 layers, 13 layers, 15 layers, 20 layers, 25 layers, 30 layers or 40 layers. The relationship between the number of layers and the number of corners is that the number of corners = N + 1; for example, if N = 1, the number of corners is 2; if N = 10, the number of corners of the fast charging battery cell is 11. The subsequent calculation of the corner position of the positive electrode or the negative electrode punching starts from the negative electrode opposite to the positive electrode tab, and the number of corners increases by 2 each time, that is, 1 on each side of each layer.

[0019] According to some embodiments of the present application, the positive electrode coating notch is a continuous solid line type notch.

[0020] According to some embodiments of the present application, at each corner, the positive electrode coating is provided with 1 to multiple parallel solid line type notches (also referred to as grooves). For example, it can specifically be 3, 4, 5, 6, 7 or 8.

[0021] According to some embodiments of the present application, the width of the positive electrode coating notch is 20-80 μm. For example, it can specifically be about 50 μm or about 60 μm. The width is the line width of the solid line type notch or the dotted line type notch. The width of the negative electrode coating notch is explained herein.

[0022] According to some embodiments of the present application, at each corner, the spacing between two adjacent solid line type notches is 1-2 mm.

[0023] According to some embodiments of the present application, the depth of the positive electrode coating notch is 1 / 4-2 / 3 of the thickness of the positive electrode coating. For example, it can specifically be about 30%, 40%, 50% or about 60%.

[0024] If the positive electrode coating notch is a dotted line type notch, the depth herein is the punching depth, i.e. the deepest depth of the dotted line type notch. The depth of the negative electrode coating notch is explained herein.

[0025] According to some embodiments of the present application, the thickness of the positive electrode coating is 20-100 μm. For example, it can specifically be about 30 μm, 40 μm, 50 μm, 60 μm, 70 μm, 80 μm or about 90 μm.

[0026] According to some embodiments of the present application, the negative electrode coating notch is a continuous solid line type notch, or a dotted line type notch formed by connecting hole structures.

[0027] When the negative electrode coating notch is a solid line type notch, the spacing between two adjacent solid line type notches is 1-2 mm. For example, it can specifically be about 1.5 mm.

[0028] When the negative electrode coating notch is a dotted line type notch, i.e. hole structures perpendicular to the negative electrode coating are arrayed at positions where the negative electrode coating notch is needed.

[0029] According to some embodiments of the present application, the width of the negative electrode coating notch is 30-120 μm. For example, it can specifically be about 50 μm, 80 μm or about 100 μm.

[0030] According to some embodiments of the present application, the depth of the negative electrode coating gap is 1 / 4 to 2 / 3 of the thickness of the negative electrode coating. For example, it can be about 30%, 40%, 50%, or about 60%.

[0031] According to some embodiments of the present application, the thickness of the negative electrode coating is 40 to 120 μm. For example, it can be about 50 μm, 60 μm, 70 μm, 80 μm, 90 μm, 100 μm, or about 110 μm.

[0032] According to some embodiments of the present application, the positive electrode coating gap penetrates through or across the positive electrode coating; and / or, the negative electrode coating gap penetrates through or across the negative electrode coating; according to some embodiments of the present application, the total number of winding layers of the fast-charging battery cell is N, the number of winding layers with the positive electrode coating gap is n; and 1≤n≤N / 2. For example, it can be about 2, 3N / 10, or N / 4.

[0033] At least one layer of the positive electrode coating gap is useful, so the lower limit is set to 1; if the positive electrode coating gap is set too much, the proportion of side reactions will also increase, so the upper limit is set to N / 2.

[0034] According to some embodiments of the present application, the fast-charging battery cell satisfies the relationship 3≤n≤N / 3. For example, it can be 3N / 20.

[0035] According to some embodiments of the present application, the total number of winding layers of the fast-charging battery cell is N, the number of winding layers with the negative electrode coating gap is m; and 3≤m≤N / 2.

[0036] In the above range, the lower limit value 3 is set because it is necessary to be compatible with small capacity, such as a fast-charging battery cell with only 6 or 10 layers; in order to match the positive electrode, and in order to achieve fast-charging performance, at least 3 layers of negative electrode coating gaps are required. The upper limit value is set to control the proportion of side reactions to some extent.

[0037] According to some embodiments of the present application, the fast-charging battery cell satisfies the relationship 3≤m≤n+1.

[0038] According to some embodiments of the present application, the raw material for preparing the negative electrode coating comprises a silicon-based negative electrode material. Compared with other types of fast-charging batteries, the fast-charging battery containing the silicon-based negative electrode material has its particularity; specifically, the silicon-based negative electrode material consumes electrolyte faster than other negative electrode materials, if no hole is punched (i.e., the coating gap is not provided), the electrolyte content is low, and the lithium precipitation at the corner is serious, if the hole is punched improperly, the consumption of electrolyte is further accelerated, which still leads to lithium precipitation at the corner. The fast-charging battery provided in the present application adjusts the position of the coating gap on the positive electrode and the negative electrode, and the amount of the coating gap, etc., as little as possible to destroy the structure of the silicon-based negative electrode material, effectively balances the relationship between the electrolyte retention amount and the electrolyte consumption amount, and can significantly improve the fast-charging performance and the fast-charging cycle performance of the fast-charging battery containing the silicon-based negative electrode material.

[0039] According to some embodiments of the present application, in the fast-charging battery, the positive electrode tab and the negative electrode tab are arranged in a staggered manner. In this way, the positive electrode tab and the negative electrode tab do not contact, avoiding the short circuit problem in the storage, transportation and use process.

[0040] According to the above description, it can be known that the fast-charging battery provided in the present application adopts a design of partially punching holes in the positive electrode and the negative electrode, realizes precise control of dynamics, ensures that there are holes in the position where the fast-charging battery has a high charging current density, solves the problem of insufficient charging, at the same time, does not punch holes in the position where the charging current density is small, avoids the damage to the positive electrode active material and the negative electrode active material, especially the silicon-based negative electrode material, reduces the side reaction of the fast-charging battery, and thus reduces the overall expansion of the fast-charging battery in the use process; and optimizes the cycle performance of the fast-charging battery.

[0041] The lithium ion battery according to the second aspect of the embodiments of the present application comprises the fast-charging battery and electrolyte infiltrating the fast-charging battery.

[0042] The lithium ion battery according to the embodiments of the present application has at least the following beneficial effects:

[0043] The rate performance and the cycle performance are significantly improved.

[0044] According to some embodiments of the present application, the lithium ion battery further comprises a battery shell; the battery shell contains the fast-charging battery and the electrolyte.

[0045] According to some embodiments of the present application, the electrolyte comprises a lithium salt and an organic solvent. Wherein,

[0046] The lithium salt comprises at least one of LiPF6, LiClO4, LiBF4, LiBOB and LiAsF6.

[0047] The concentration of the lithium salt in the electrolyte is 0.5-2 mol / L. For example, it can be about 1 mol / L or about 1.5 mol / L.

[0048] The organic solvent includes at least one of ethylene carbonate (EC), propylene carbonate (PC), diethyl carbonate (DEC) and propyl propionate (PP).

[0049] The electric product according to the third aspect of the present application, the raw material for preparing the electric product includes the fast-charging battery cell or the lithium ion battery.

[0050] According to some embodiments of the present application, the electric product includes at least one of a digital product and a new energy vehicle. The digital product includes at least one of a mobile phone, a tablet computer, a camera and a notebook computer.

[0051] Unless otherwise specified, "about" in the present application actually means that the allowed error is within ±2%, for example, about 100 actually means 100±2%×100.

[0052] Unless otherwise specified, "between" in the present application includes the number, for example, "between 2-3" includes the end point values 2 and 3.

[0053] Additional aspects and advantages of the present application will be in part apparent and in part pointed out hereinafter. BRIEF DESCRIPTION OF DRAWINGS

[0054] The present application will be further described below in conjunction with the accompanying drawings and examples, in which:

[0055] Fig. 1 is a schematic structural diagram of a positive electrode (upper) and a negative electrode (lower) used in an embodiment of the present application.

[0056] Reference numerals:

[0057] Positive electrode current collector 110, positive electrode coating 120, positive electrode coating gap 121, positive electrode tab 130, adhesive tape 140;

[0058] Negative electrode current collector 210, negative electrode coating 220, negative electrode coating gap 221, negative electrode tab 230. DETAILED DESCRIPTION

[0059] The embodiments of the present application are described in detail below, examples of which are shown in the accompanying drawings, in which the same or similar reference numerals represent the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by referring to the accompanying drawings are exemplary and are only used to explain the present application, and cannot be understood as a limitation of the present application.

[0060] In the description of the present application, unless otherwise explicitly defined, the words such as arrangement, installation, connection and the like should be understood broadly, and the person skilled in the art can determine the specific meaning of the above words in the present application in combination with the specific content of the technical solution.

[0061] Embodiment 1

[0062] Referring to FIG. 1, the present example provides a fast-charging battery cell, which is wound by a positive electrode, a separator and a negative electrode, and the number of winding layers is 20; the separator is arranged between the positive electrode and the negative electrode;

[0063] Referring to FIG. 1 (upper), the positive electrode used in the present example includes a positive electrode current collector 110, a positive electrode coating layer 120 arranged on the surface of the positive electrode current collector 110, and a middle positive electrode tab 130 electrically connected to the positive electrode current collector 110; the edge position of the positive electrode tab 130 and the positive electrode coating layer 120 is attached with a tape 140; to avoid the edge burr piercing the separator and causing short circuit of the fast-charging battery cell.

[0064] From the positive electrode tab 130, at the corners of the fast-charging battery cell, the positive electrode coating layer 120 is provided with a positive electrode coating layer notch 121; a total of 4 corners are provided with positive electrode coating layer notches, and a total of 5 positive electrode coating layer notches are provided at each corner.

[0065] Each positive electrode coating layer notch is a solid line type notch with a width of 80 μm and a depth of 15 μm; at each corner, the spacing between the adjacent two positive electrode coating layer notches is 1.5 mm; the positive electrode coating layer notch crosses the positive electrode coating layer.

[0066] The positive electrode is arranged as follows: the positive electrode active material LiCoO2 (purchased from Xiamen Tungsten New Energy), the conductive agent acetylene black, the conductive agent carbon nanotube, and the binder polyvinylidene fluoride (PVDF) are uniformly grinded in NMP according to the mass ratio of 97.9:0.6:0.5:1.0, and then coated on the surface of the positive electrode current collector aluminum foil on both sides to form a positive electrode coating layer with a single side thickness of 35 μm; then cold-pressed and slitted to obtain a suitable size, and finally the positive electrode coating layer notch is set by laser etching technology according to the above parameters.

[0067] Referring to FIG. 1 (lower), the negative electrode used in the present example includes a negative electrode current collector 210, a negative electrode coating layer 220 arranged on the surface of the negative electrode current collector 210, and a middle negative electrode tab 230 electrically connected to the negative electrode current collector 210; the edge position of the negative electrode tab 230 and the negative electrode coating layer 220 is attached with a tape 140; to avoid the edge burr piercing the separator and causing short circuit of the fast-charging battery cell.

[0068] The negative electrode coating 220 is provided with a negative electrode coating notch 221 around the projection position of the positive electrode tab 130 on the negative electrode; the negative electrode coating notch 221 is uniformly distributed on the entire surface of the negative electrode, and a total of m = 3 layers of surfaces are provided. The negative electrode coating notch 221 is a solid line type notch, with a width of 100 μm and a depth of 15 μm; the spacing between adjacent two negative electrode coating notches is 1.5 mm; the negative electrode coating notch spans across the negative electrode coating.

[0069] The negative electrode is provided in the following manner: the negative electrode active material, dispersant and binder are mixed in water in a weight ratio of 97.7:1:1.3 to form a slurry; the slurry is coated on both sides of the negative electrode current collector copper foil to obtain a negative electrode coating with a single side thickness of 40 μm, and then cold-pressed and slitted to obtain a negative electrode with a suitable size; finally, the negative electrode coating notch is laser etched on the surface of the negative electrode coating according to the above parameters.

[0070] The negative electrode active coating used in this example is a mixture of graphite and silicon-carbon negative electrode material in a mass ratio of 9:1, both of which are purchased from Zichen.

[0071] Separator: The separator used in this example is purchased from Zhuogao and is composed of a PP separator base layer and a coating layer provided on the surface of the PP separator base layer; the coating layer has a thickness of 2 μm and is a mixture of vinylidene fluoride and aluminum oxide ceramic particles in a mass ratio of 50%:50%.

[0072] It should be noted that the length of the positive electrode and the negative electrode, the number and width of the positive electrode coating notch and the negative electrode coating notch in FIG. 1 are all schematic, and the parameters measured from the figure do not represent the real parameters of this example.

[0073] Examples 2-11 and Comparative Example 1 each provide a fast-charging battery cell, which is different from Example 1 in that:

[0074] Some parameters are different, and the specific differences are shown in Table 1.

[0075] Table 1: Some parameters of Examples 1-11 and Comparative Example 1

[0076] Application Example

[0077] This example provides a lithium ion battery, which is specifically composed of a battery shell, a battery cell and an electrolyte, wherein the battery shell contains the battery cell and the electrolyte; the electrolyte infiltrates the battery cell; and the battery cell is a fast-charging battery cell provided by the examples or the comparative example.

[0078] The preparation method of the electrolyte is as follows: ethylene carbonate (EC), propylene carbonate (PC), diethyl carbonate (DEC) and propyl propionate (PP) are mixed in a volume ratio of 1:1:4:4 to obtain a mixed organic solvent, and then a fully dried lithium salt LiPF6 is dissolved in the mixed organic solvent in a proportion of 1 mol / L to prepare the electrolyte.

[0079] Test Example

[0080] This example tests the charge window and cycle performance of the lithium ion battery obtained in the application example, wherein,

[0081] The charge window test system: after constant-rate charging at a specific rate X to 4.5V, CV to 0.05C, 0.7C DC to 3.0V. After 20 cycles, disassemble the interface, and if the interface does not have lithium precipitation, it is considered that the charging capacity passes at the charging rate of X, and the charging rate of X+0.1C is measured until the charging rate (charging capacity) that does not precipitate lithium is obtained, and recorded in Table 2.

[0082] The cycle system: after constant-rate charging at the rate obtained in the charge window test that does not precipitate lithium, 1.8C CC to 4.5V, CV to 0.05C, 0.7C DC to 3.0V. Record the cycle number until the capacity is lower than 80%. The test results are shown in Table 2.

[0083] Table 2 Performance of fast-charging battery cores obtained in examples and comparative examples

[0084] As can be seen from the results of Comparative Examples 1-3, when the number of layers of the negative electrode coating notch is kept unchanged, the charging capacity of the fast-charging battery core is basically unchanged, but as the number of layers of the positive electrode coating notch increases, the cycle performance shows a trend of increasing. This is because the charging capacity mainly depends on the ability of the negative electrode to accept lithium ions, while the cycle performance depends on the ability of the positive and negative electrodes to consume electrolyte, as well as the amount of electrolyte retained, etc. Therefore, increasing the number of layers of the positive electrode coating notch can improve the cycle performance.

[0085] As can be seen from Comparative Examples 2, 4-6, when the number of layers of the positive electrode coating notch is unchanged and the number of layers of the negative electrode coating notch is increased, the charging capacity of the fast-charging battery core shows a trend of first increasing and then balancing, while the cycle performance shows a trend of first increasing and then decreasing. This is because when the distance from the negative electrode tab is far, the current density of the negative electrode tends to balance, and further increasing the number of layers of the negative electrode coating notch will not significantly affect the ability of the negative electrode to accept lithium ions, but with the increase of the amount of negative electrode coating notch, the side reaction between the silicon-carbon negative electrode material and the electrolyte in the negative electrode will increase, thereby reducing the cycle performance.

[0086] As can be seen from Comparative Examples 7-8, 11 and other examples, when the number of winding layers of the fast-charging battery core is small, the technical solution provided by the present application is still applicable and can achieve good technical effects.

[0087] From Comparative Example 1, Example 4 and Examples 8-11, it can be seen that when the ratio of the positive electrode coating notch and the negative electrode coating notch is kept unchanged, with the increase of n / N, the charging capacity and the cycle performance both appear the trend of first increasing and then decreasing, the reason is that with the increase of n / N, the capacity of the negative electrode to accept lithium ions and the storage capacity of the electrolyte are both increased, and the side reaction is also increased; the weights of the three factors are different, and the above results appear after the joint action. In addition, when the ratio of the positive electrode coating notch and the negative electrode coating notch, and n / N are kept unchanged, the overall winding layers of the fast-charging battery are increased, the charging capacity and the cycle performance are slightly decreased; this is because the heat dissipation capacity of the large-capacity fast-charging battery is decreased, and thus the occurrence of the side reaction is increased.

[0088] From the comparative example and Comparative Example 1, it can be seen that the fast-charging battery provided by the application can effectively improve the charging capacity and the cycle performance by reasonably setting the positions of the notches on the positive electrode and the negative electrode. The lithium ion battery comprising the above fast-charging battery has excellent performance, and is expected to be used in digital products and new energy vehicles.

[0089] From Comparative Example 4 and Comparative Examples 1-3, it can be seen that the fast-charging battery provided by the application can improve the fast-charging and cycle performance in a small range if only the positive electrode coating notch or only the negative electrode coating notch is set, but the improvement effect is very limited.

[0090] The embodiments of the application are described in detail above in combination with the drawings, but the application is not limited to the above embodiments, and various changes can be made within the knowledge range possessed by those skilled in the art without departing from the purpose of the application.

Claims

1. A fast-charging battery cell, which is wound by a positive electrode, a separator and a negative electrode; the separator is arranged between the positive electrode and the negative electrode; the negative electrode comprises a negative electrode current collector, a negative electrode coating arranged on the surface of the negative electrode current collector, and a middle negative electrode tab electrically connected with the negative electrode current collector; the positive electrode comprises a positive electrode current collector, a positive electrode coating arranged on the surface of the positive electrode current collector, and a middle positive electrode tab electrically connected with the positive electrode current collector; a positive electrode coating notch is arranged on the positive electrode coating at the corner of the fast-charging battery cell from the positive electrode tab; a negative electrode coating notch is arranged on the negative electrode coating around the projection position of the positive electrode tab on the negative electrode.

2. The fast charge cell of claim 1, wherein, The total number of winding layers of the fast-charging battery cell is N, the number of winding layers with the positive electrode coating notch is n; and 1≤n≤N / 2; and / or, the total number of winding layers of the fast-charging battery cell is N, the number of winding layers with the negative electrode coating notch is m; and 3≤m≤N / 2.

3. The fast charge cell of claim 1, wherein, The positive electrode coating notch and / or the negative electrode coating notch is a continuous solid line notch, or a dotted line notch connected by hole structures.

4. The fast charge cell of claim 3, wherein, The width of the positive electrode coating notch is 20-80 μm; and / or, the width of the negative electrode coating notch is 30-120 μm.

5. The fast charge cell of claim 3, wherein, The depth of the positive electrode coating notch is 1 / 4-2 / 3 of the thickness of the positive electrode coating; and / or, the depth of the negative electrode coating notch is 1 / 4-2 / 3 of the thickness of the negative electrode coating.

6. The fast charge cell of claim 3, wherein, The interval of the negative electrode coating notch is 1-2 mm.

7. The fast charge cell of claim 2, wherein, The total number of winding layers N of the fast-charging battery cell ranges from 10 to 50; and / or, the raw material for preparing the negative electrode coating comprises a silicon-based negative electrode material.

8. The fast-charging cell of any one of claims 1-7, wherein, The thickness of the positive electrode coating is 20-100 μm; and / or, the thickness of the negative electrode coating is 40-120 μm. 9.A lithium ion battery, which comprises the fast-charging battery cell according to any one of claims 1-7, and an electrolyte infiltrating the fast-charging battery cell. 10.An electric product, which comprises the fast-charging battery cell according to any one of claims 1-8, or the lithium ion battery according to claim 9, as a raw material.

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