Battery

Abstract

The invention discloses a battery, comprising: a housing having a storage cavity; the battery cell is arranged in the storage cavity, the battery cell comprises a negative plate, a groove is formed in the negative plate, and the volume of the groove is V; the electrolyte is arranged in the storage cavity, and the viscosity value of the electrolyte is omega; wherein the volume of the groove and the viscosity value of the electrolyte meet the following formula: phi = omega / V, phi is the viscosity value of the electrolyte under the unit volume of the groove, and the value range of phi is that phi is more than or equal to 4.69 mPas / mm < 3 > and less than or equal to 240 mPas / mm < 3 >; the compaction density of the negative plate is P, the depth of the groove is H, and P and H meet the condition that P * H / omega is larger than or equal to 4.44 and smaller than or equal to 56.67. The battery provided by the invention not only can effectively avoid the problem of lithium precipitation, but also can have the characteristic of relatively high conductivity.

Description

Technical Field

[0001] The present invention relates to the technical field of batteries, and in particular to a battery. Background Art

[0002] Nowadays, the battery cells in the industry are developing towards high energy density and fast charging. However, the two are often difficult to be compatible at the same time. If you blindly pursue high energy density, you will lose the rate performance of the battery cell; but if you preserve the rate performance, you will also lose energy density. Setting grooves on the negative electrode sheet as a new pore-making technology is currently an effective method to improve the rate performance of the battery cell. Although this technology creates more grooves on the negative electrode sheet, it increases the contact area between the electrode sheet and the electrolyte, allowing the battery cell to absorb more electrolyte, Li + The transmission direction can be combined with the horizontal and vertical directions, and the transmission distance is shortened accordingly, thereby significantly improving the rate performance of the battery cell. However, the setting of the grooves also leads to the loss of active materials, and the energy density of the battery cell is bound to decrease.

[0003] In order to meet the needs of high energy density and fast charging at the same time, high-density negative electrode materials are often developed. Under high compaction, the porosity of the negative electrode decreases, the tortuosity increases, and the electrolyte infiltration faces problems. These problems can be effectively avoided by setting grooves. Therefore, on the basis of improving the compaction of the negative electrode, the grooves are reasonably set, which can not only make up for the energy density lost by setting the grooves, but also improve the fast charging performance. In addition, when the depth of the groove is set too deep and the viscosity of the electrolyte is not suitable, there is a risk that the material area deep in the groove cannot be completely infiltrated with the electrolyte, resulting in serious groove lithium precipitation in the later cycles of the battery cell. Therefore, how to balance the compaction density of the negative electrode sheet, the size of the groove and the strength of the electrolyte viscosity is very important for the preparation of high energy density and fast charging cells.

[0004] In the related art, after the battery cell is placed in the shell, an electrolyte is injected into the shell. The electrolyte plays the role of conducting electrons between the positive and negative electrodes of the lithium battery, and is the guarantee for the lithium battery to obtain high voltage and high specific energy. Among them, the viscosity of the electrolyte, as one of the important parameters for evaluating the performance of the electrolyte, directly affects the fluidity and conductivity of the electrolyte. It can be imagined that the lower the viscosity of the electrolyte, the faster the fluidity of the electrolyte and the higher the conductivity. The higher the conductivity, the faster the battery charges. In addition, the conductivity is also affected by the dielectric constant. Generally, the larger the dielectric constant, the greater the conductivity. The dielectric constant is often closely related to the physical properties of the electrolyte. Generally speaking, the larger the viscosity of the electrolyte, the larger the dielectric constant. Specifically, the viscosity of the electrolyte cannot be too high or too low. Too high viscosity of the electrolyte will affect the fluidity of the electrolyte, reduce the ion migration rate, and then lead to a decrease in conductivity; too low viscosity of the electrolyte will affect the dielectric constant of the electrolyte and reduce the conductivity. After the grooves are set on the pole piece, when the electrolyte is injected into the shell, if the depth is large and the viscosity of the electrolyte is too high, the electrolyte may not penetrate deep into the hole, which will cause the problem of lithium deposition in the battery. However, if the viscosity of the electrolyte is simply reduced, it means that the dielectric constant of the electrolyte is also reduced, and the conductivity will also be affected, which may still not meet the process requirements. Summary of the invention

[0005] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, the present invention provides a battery that can not only effectively avoid the problem of lithium deposition, but also has the characteristic of high electrical conductivity.

[0006] A battery according to an embodiment of the present invention includes:

[0007] A housing having a storage cavity;

[0008] A battery cell is disposed in the storage cavity, wherein the battery cell comprises a negative electrode sheet, and a groove is disposed on the negative electrode sheet, and the volume of the groove is V;

[0009] An electrolyte is disposed in the storage cavity, and the viscosity of the electrolyte is ω;

[0010] The volume of the groove and the viscosity of the electrolyte satisfy the following formula: Φ = ω / V, where Φ is the viscosity of the electrolyte per unit volume of the groove, and the value range of Φ is: 4.69 mPas / mm 3 ≤Φ≤240mPas / mm 3 ; The compaction density of the negative electrode sheet is P, the depth of the groove is H, and P and H satisfy: 4.44≤P*H / ω≤56.67.

[0011] The battery according to the embodiment of the present invention has at least the following beneficial effects: after the negative electrode sheet is provided with a groove, the battery cell is placed in the storage cavity, and finally the electrolyte is injected. Since the viscosity value of the electrolyte per unit volume of the groove meets 4.69 mPas / mm 3 ≤Φ≤240mPas / mm 3 , and 4.44≤P*H / ω≤56.67, therefore, the battery can not only effectively avoid the problem of lithium plating, but also have the characteristic of higher electrical conductivity.

[0012] In batteries according to some embodiments of the present invention, the viscosity of the electrolyte satisfies 0.6 mPas≤ω≤1.8 mPas.

[0013] According to some embodiments of the present invention, the volume of the groove satisfies: 0.0075mm 3 ≤V≤0.128mm 3 .

[0014] In the battery according to some embodiments of the present invention, the depth of the groove is H, which satisfies: 5 μm≤H≤20 μm

[0015] In batteries according to some embodiments of the present invention, a width of the groove is D, which satisfies: 50 μm≤D≤80 μm.

[0016] In batteries according to some embodiments of the present invention, the length of the groove is L, satisfying: 30 μm≤L≤80 μm.

[0017] In the battery according to some embodiments of the present invention, the battery cell further includes a positive electrode sheet and a separator, and the separator is located between the positive electrode sheet and the negative electrode sheet.

[0018] According to some embodiments of the present invention, the compaction density of the negative electrode sheet is P, which satisfies: 1.6 g / cm 3 ≤P≤1.7g / cm 3 .

[0019] According to some embodiments of the battery of the present invention, a plurality of the grooves are provided, and the plurality of the grooves are spaced apart along the length direction of the negative electrode sheet.

[0020] In batteries according to some embodiments of the present invention, a distance d between two adjacent grooves satisfies: 1.0 mm ≤ d ≤ 2.5 mm.

[0021] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The present invention will be further described below with reference to the accompanying drawings and embodiments, wherein:

[0023] Figure 1 is a flow chart of a battery manufacturing method according to a first embodiment of the present invention;

[0024] Figure 2 is a flow chart of a battery manufacturing method according to a first embodiment of the present invention;

[0025] Figure 3 is a schematic diagram of a pole piece in a battery according to a first embodiment of the present invention;

[0026] Figure 4 Schematic diagram of a pole piece in a battery according to a second embodiment of the present invention.

[0027] Reference numerals:

[0028] Pole piece 100 and groove 200 . DETAILED DESCRIPTION

[0029] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0030] In the description of the present invention, it should be understood that descriptions involving orientations, such as up, down, front, back, left, right, etc., and orientations or positional relationships indicated are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0031] In the description of the present invention, "several" means more than one, "many" means more than two, "greater than", "less than", "exceed", etc. are understood to exclude the number itself, and "above", "below", "within", etc. are understood to include the number itself. If there is a description of "first" or "second", it is only used for the purpose of distinguishing technical features, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features or implicitly indicating the order of the indicated technical features.

[0032] In the description of the present invention, unless otherwise clearly defined, terms such as setting, installing, connecting, etc. should be understood in a broad sense, and technicians in the relevant technical field can reasonably determine the specific meanings of the above terms in the present invention based on the specific content of the technical solution.

[0033] In the description of the present invention, the description with reference to the terms "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0034] Please refer to Figure 1 In some embodiments, the method for determining the viscosity value of the electrolyte includes the following steps:

[0035] A groove 200 is provided on the pole piece 100, and the volume of the groove 200 is calculated and recorded as V (in mm). 3 );

[0036] The viscosity of the electrolyte in the groove with a volume of 200 units is obtained and recorded as Φ (in mPas / mm 3 ), satisfying: 4.69≤Φ≤240;

[0037] The viscosity of the electrolyte is recorded as ω (in mPas), and according to ω=V·Φ, the viscosity of the electrolyte is calculated and obtained.

[0038] Specifically, under the premise of providing the groove 200 in the pole piece 100, the viscosity value of the electrolyte under the unit volume of the groove 200 satisfies 4.69≤Φ≤240. When the volume of the groove 200 and the viscosity value of the electrolyte under the unit volume of the groove 200 are known, the viscosity value of the electrolyte can be calculated by the formula ω=V·Φ. After determining the viscosity value of the electrolyte, the electrolyte that meets the condition can be injected into the shell to complete the manufacture of the battery. In this way, the battery manufactured by the method for determining the viscosity value of the electrolyte can not only effectively avoid the problem of lithium precipitation, but also have the characteristics of high conductivity.

[0039] The following is an introduction to the method for determining the viscosity value of the electrolyte. In the present embodiment, a groove 200 is provided on the pole piece 100 to improve the fast charging capability of the battery, such as providing a rectangular groove 200 on the negative pole piece. Among them, after the pole piece 100 is formed into a battery cell by lamination or winding, the battery cell is placed in a shell, and finally the electrolyte is injected into the shell. Since a groove 200 is provided on the battery cell (the pole piece 100 forms a battery cell), after an electrolyte with a conventional viscosity value is injected into the battery cell, the electrolyte may not be able to completely penetrate into the depth of the groove 200 of the pole piece 100. In order to solve this problem, when the viscosity value of the electrolyte under the unit volume of the groove 200 meets 4.69mPas / mm 3≤Φ≤240mPas / mm 3 When the battery is not only able to effectively avoid the problem of lithium deposition, but also has the characteristics of high conductivity. Further, when the viscosity of the electrolyte under the unit volume of the groove 200 is greater than 240mPas / mm 3 When the viscosity of the electrolyte in the groove 200 unit volume is too large, it will cause the battery to have lithium deposition problems. When the viscosity of the electrolyte in the groove 200 unit volume is less than 4.69mPas / mm 3 When the electrolyte viscosity is too low, the conductivity of the battery will be too low.

[0040] It should be added that, in this embodiment, when the battery is manufactured, the electrode 100 will be provided with a groove 200 to improve the fast charging capability of the battery. Therefore, after determining the viscosity value of the electrolyte under the unit volume of the groove 200, the viscosity value of the electrolyte can be further proportioned in the subsequent steps of battery manufacturing.

[0041] It is further added that the groove 200 is provided on the pole piece 100 specifically means that the groove 200 is formed on the active material layer of the pole piece 100 by means of laser or other means. The volume of the above-mentioned groove 200 refers to the total volume of the groove 200, that is, a plurality of grooves 200 can be provided on the pole piece 100, and when calculated according to the formula ω=V·Φ, V is the sum of the volumes of all the grooves 200. In addition, when the grooves 200 are provided, the volume that each groove 200 should occupy can also be calculated based on the total volume and the number of grooves 200 to be provided.

[0042] In another embodiment, if the staff first calculates the viscosity of the electrolyte, then according to the formula V=ω / Φ, the staff can infer the volume of the groove 200 that needs to be set in the electrode 100, so that the battery can not only effectively avoid the problem of lithium deposition, but also have the characteristic of high conductivity. Figure 2 In some embodiments, the method for determining the slot volume comprises the following steps:

[0043] The viscosity of the electrolyte is obtained, denoted as ω (in mPas);

[0044] Before the groove 200 is provided on the electrode sheet 100, the viscosity of the electrolyte per unit volume of the groove 200 is determined, which is recorded as Φ (in units of mPas / mm 3 ), satisfying: 4.69≤Φ≤240;

[0045] The volume of the groove 200 is denoted as V (in mm 3 ), according to V=ω / Φ, the volume of the groove 200 is calculated.

[0046] Specifically, before the electrode 100 is provided with the groove 200, the viscosity value of the electrolyte per unit volume of the groove 200 satisfies 0.77≤Φ≤15000. After knowing the viscosity value of the electrolyte and the viscosity value of the electrolyte per unit volume of the groove 200, the volume of the groove 200 required to be provided on the electrode 100 can be calculated by the formula V=ω / Φ. After determining the volume of the groove 200, the groove 200 can be provided on the electrode 100 so that the volume of the groove 200 satisfies the calculated value, thereby completing the manufacturing of the groove 200. In this way, the battery with the groove 200 can not only effectively avoid the problem of lithium precipitation, but also have the characteristics of high conductivity.

[0047] The method for determining the slot volume is introduced again below. In the present embodiment, a groove 200 is provided on the pole piece 100 to improve the fast charging capability of the battery, such as providing a rectangular groove 200 on the negative pole piece. Among them, after the pole piece 100 is formed into a battery cell by lamination or winding, the battery cell is placed in a shell, and finally an electrolyte is injected into the shell. Since a groove 200 is provided on the battery cell (the pole piece 100 forms a battery cell), after an electrolyte with a conventional viscosity value is injected into the battery cell, the electrolyte may not be able to completely penetrate into the depth of the groove 200 of the pole piece 100. In order to solve this problem, when the viscosity value of the electrolyte under the unit volume of the groove 200 satisfies 4.69≤Φ≤240, the battery can not only effectively avoid the problem of lithium precipitation, but also have the characteristic of higher conductivity. Furthermore, when the viscosity value of the electrolyte under the unit volume of the groove 200 is greater than 240mPas / mm 3 When the viscosity of the electrolyte in the groove 200 unit volume is too large, it will cause the battery to have lithium deposition problems. When the viscosity of the electrolyte in the groove 200 unit volume is less than 4.69mPas / mm 3 When the electrolyte viscosity is too low, the conductivity of the battery will be too low.

[0048] It should be added that, in this embodiment, when the battery is manufactured, the electrode piece 100 will be provided with a groove 200 to improve the fast charging capability of the battery. Therefore, after the viscosity value of the electrolyte is determined, the groove 200 can be provided on the electrode piece 100 according to the result in the subsequent steps of battery manufacturing.

[0049] It is further added that the groove 200 is provided on the pole piece 100 specifically refers to the groove 200 being formed on the active material layer of the pole piece 100 by means of laser or other means. The volume of the groove 200 refers to the total volume of the groove 200, that is, a plurality of grooves 200 can be provided on the pole piece 100, and when calculated according to the formula V=ω / Φ, V is the sum of the volumes of all the grooves 200. In addition, when the grooves 200 are provided, the volume that each groove 200 should occupy can also be calculated based on the total volume and the number of grooves 200 to be provided.

[0050] In some embodiments, the battery includes: a housing, a battery cell and an electrolyte. The housing has a storage cavity. The battery cell is disposed in the storage cavity, and the battery cell includes a pole piece 100, which may be a negative pole piece, and a groove 200 is disposed on the negative pole piece, and the volume of the groove 200 is V (unit: mm 3 ); the electrolyte is disposed in the storage chamber, and the viscosity of the electrolyte is ω (in mPas). The volume of the groove 200 and the viscosity of the electrolyte satisfy the following formula: Φ = ω / V, where Φ is the viscosity of the electrolyte per unit volume of the groove 200 (in mPas / mm 3 ), the value range of Φ is: 4.69≤Φ≤240. The compaction density of the negative electrode sheet is P, the depth of the groove 200 is H, and P and H satisfy: 4.44≤P*H / ω≤56.67. Specifically, after the electrode 100 is provided with the groove 200, the electrode 100 forms a battery cell, the battery cell is placed in the storage cavity, and finally the electrolyte is injected. Since the viscosity value of the electrolyte per unit volume of the groove 200 satisfies 4.69≤Φ≤240, and 4.44≤P*H / ω≤56.67. Therefore, the battery can not only effectively avoid the problem of lithium plating, but also have the characteristic of higher electrical conductivity.

[0051] Furthermore, since the groove 200 is provided on the battery cell (the electrode 100 forms the battery cell), after the electrolyte with a conventional viscosity value is injected into the battery cell, the electrolyte may not be able to completely penetrate into the deep groove 200 of the electrode 100. In order to solve this problem, when the viscosity value of the electrolyte per unit volume of the groove 200 meets 4.69mPas / mm 3 ≤Φ≤240mPas / mm 3 When the battery is not only able to effectively avoid the problem of lithium deposition, but also has the characteristics of high conductivity. Further, when the viscosity of the electrolyte under the unit volume of the groove 200 is greater than 240mPas / mm 3 When the viscosity of the electrolyte in the groove 200 unit volume is too large, it will cause the battery to have lithium deposition problems. When the viscosity of the electrolyte in the groove 200 unit volume is less than 4.69mPas / mm 3When the electrolyte viscosity is too low, the conductivity of the battery will be too low. Please refer to the table below for details.

[0052] In the table below, the capacity retention rate refers to the percentage of the initial capacity of the battery cell after 1,000 cycles of 4C step charging to 4.25V and 2C charging to the cut-off voltage. The rate performance refers to the ratio of the 4C discharge capacity to the 0.2C discharge capacity at room temperature. The degree of lithium plating refers to the lithium plating of the battery cell after the battery interface is disassembled after 1,000 cycles.

[0053]

[0054]

[0055] It should be added that in the above table, the comparative example uses a conventional battery cell as a reference, that is, the case where no groove 200 is set on the electrode piece 100 of the battery cell. By comparing Examples 1-10 with Comparative Example 1, it can be seen that laser drilling a groove 200 on the electrode piece 100 can effectively improve the rate performance of the battery cell, and the rate performance of the battery cell is crucial, compared with the scheme without drilling holes. When the volume of the groove 200 is constant, the smaller the viscosity ω of the electrolyte, the smaller the degree of lithium precipitation of the battery cell, and the higher the capacity retention rate. However, when the hole volume or the electrolyte viscosity is not suitable, the battery cell capacity retention rate has no obvious advantage. When the volume of the groove 200 is larger, the electrolyte viscosity value needs to be smaller, because the electrolyte with a smaller viscosity can ensure the infiltration of the active material layer at the groove 200. However, the viscosity value of the electrolyte cannot be reduced indefinitely, because if the viscosity is too low, the dielectric constant of the electrolyte will also become smaller, thereby affecting its performance. In order to compensate for the loss of energy density caused by the groove setting, the compaction of the negative electrode sheet is usually increased. As can be seen from the table, the greater the compaction P, the deeper the drilling depth is to ensure the rate performance. The formula relationship proposed in this application is conducive to the selection of electrolyte with suitable viscosity for laser drilling. It not only effectively avoids the problem of lithium precipitation in the battery, but also improves the cycle performance of the battery cell.

[0056] Further, in Examples 1 to 10, the viscosity of the electrolyte satisfies 0.6 mPas ≤ ω ≤ 1.8 mPas. Specifically, by comparing Examples 9 and 10 with Comparative Examples 3 and 4, it can be seen that when the viscosity of the electrolyte is greater than 1.8 mPas, the viscosity of the electrolyte is too large, and the viscosity Φ of the electrolyte per unit volume is too large, which will cause the electrolyte to have poor fluidity in the shell, so that the electrolyte may not be able to penetrate deep into the groove 200. When the viscosity of the electrolyte is less than 0.6 mPas, the viscosity of the electrolyte is too small, and the viscosity Φ of the electrolyte per unit volume is too small, which will cause the conductivity of the electrolyte to be too low.

[0057] Furthermore, in some embodiments, the volume of the groove 200 satisfies: 0.0075mm3≤V≤0.128mm3. Specifically, by comparing Examples 9 and 10 with Comparative Examples 2 and 6, it can be seen that when the volume of the groove 200 is greater than 0.128mm3, since the groove 200 is provided on the active material layer of the pole piece 100, it can be imagined that the larger the volume of the groove 200, the more active material layer will be removed, which will result in a lower energy density of the battery. When the volume of the groove 200 is less than 0.0075mm3, the volume of the groove 200 is too small, resulting in poor fast charging performance of the battery.

[0058] By comparing Example 9 with Comparative Example 5, it can be seen that when the drilling depth H and the electrolyte viscosity ω are constant, excessive compaction causes P*H / ω to exceed the range, which also leads to a decrease in rate performance and an increase in the degree of lithium precipitation.

[0059] For further information, please refer to Figure 3 In some embodiments, the depth of the groove 200 is H, which satisfies 5μm≤H≤20μm. Specifically, when the depth of the groove 200 is greater than 20μm, the greater the depth of the groove 200, the more unfavorable it is for manufacturing during the manufacturing process, because it may cause the risk of punching through the foil, and at the same time cause the CB value at the hole groove to be mismatched, thereby deteriorating the lithium deposition interface; when the depth of the groove 200 is less than 5μm, the depth of the groove 200 is too shallow, and the process manufacturing is not very meaningful.

[0060] For further information, please refer to Figure 3 In some embodiments, the width of the groove 200 is D, which satisfies: 50 μm ≤ D ≤ 80 μm. Specifically, when the width of the groove 200 is greater than 80 μm, the greater the width of the groove 200, the less the number of grooves 200 will be when multiple grooves 200 are manufactured. A greater number of grooves 200 can ensure that the electrolyte infiltrates the active material layer faster. When the width of the groove 200 is less than 50 μm, the width of the groove 200 is too small and has no practical significance.

[0061] For further information, please refer to Figure 4 In some embodiments, the length of the groove 200 is L, which satisfies: 30 μm ≤ L ≤ 80 μm. Specifically, when the length of the groove 200 is greater than 80 μm, the greater the length of the groove 200, the more active material will be removed. The energy density of the battery is reduced. When the length of the groove 200 is less than 30 μm, the length of the groove 200 is too small, which will cause the electrolyte to infiltrate the active material layer poorly.

[0062] Further, in some embodiments, the electrode sheet 100 includes a positive electrode sheet, a negative electrode sheet and a separator, and the groove 200 is provided on the negative electrode sheet. The separator is located between the positive electrode sheet and the negative electrode sheet. Specifically, after the groove 200 is provided on the negative electrode sheet, when the electrolyte infiltrates the battery cell, the electrolyte can quickly infiltrate the active material layer of the negative electrode sheet, which can improve the fast charging performance of the battery cell. After the separator is located between the positive electrode sheet and the negative electrode sheet, the separator can effectively prevent the positive electrode sheet and the negative electrode sheet from contacting and short-circuiting.

[0063] Furthermore, in some embodiments, a plurality of grooves 200 are provided, and the plurality of grooves 200 are arranged at intervals along the length direction of the negative electrode sheet. Specifically, the plurality of grooves 200 can increase the contact area between the active material layer of the negative electrode sheet and the electrolyte, thereby allowing the electrolyte to infiltrate the active material layer more quickly, thereby improving the fast charging performance of the battery.

[0064] Furthermore, in some embodiments, the spacing between two adjacent grooves 200 is d, which satisfies: 1.0 mm ≤ d ≤ 2.5 mm. When the spacing between the grooves 200 is greater than 2.5 mm, the number of grooves 200 is small, which reduces the wetting performance. When the spacing between the grooves 200 is less than 1 mm, the processing of the grooves 200 and the negative electrode sheet is more difficult.

[0065] It should be added that the electrolyte includes but is not limited to inorganic salt electrolytes and organic electrolytes. The material of the negative electrode sheet can be composed of single graphite or silicon carbon graphite. The material of the positive electrode sheet can be one or more of lithium cobalt oxide, ternary materials, lithium-rich materials or other positive electrode materials. The battery cell also includes a diaphragm, which is located between the positive electrode sheet and the negative electrode sheet. The material of the diaphragm includes one or more of polyethylene, polypropylene, polyvinylidene fluoride and their multilayer composite films.

[0066] The embodiments of the present invention are described in detail above in conjunction with the accompanying drawings, but the present invention is not limited to the above embodiments. Various changes can be made within the knowledge of ordinary technicians in the relevant technical field without departing from the purpose of the present invention. In addition, the embodiments of the present invention and the features in the embodiments can be combined with each other without conflict.

Claims

1. A battery, characterized in that: include: A housing having a storage cavity; A battery cell is disposed in the storage cavity, wherein the battery cell comprises a negative electrode sheet, and a groove is disposed on the negative electrode sheet, and the volume of the groove is V; The electrolyte is arranged in the storage cavity, and the viscosity of the electrolyte is ω; wherein the volume of the groove and the viscosity of the electrolyte satisfy the following formula, Φ=ω / V, Φ is the viscosity of the electrolyte per unit volume of the groove, and the value range of Φ is: 4.69mPas / mm 3 ≤Φ≤240mPas / mm 3 ; The compaction density of the negative electrode sheet is P, the depth of the groove is H, and P and H satisfy: 4.44≤P*H / ω≤56.

67.

2. The battery according to claim 1, characterized in that The viscosity of the electrolyte satisfies 0.6 mPas≤ω≤1.8 mPas.

3. The battery according to claim 1, characterized in that The volume of the groove meets the following requirements: 0.0075 mm 3 ≤V≤0.128mm 3 .

4. The battery according to claim 1, characterized in that The depth of the groove is H, which satisfies: 5 μm≤H≤20 μm.

5. The battery according to claim 1, characterized in that The width of the groove is D, which satisfies: 50 μm≤D≤80 μm.

6. The battery according to claim 1, characterized in that The length of the groove is L, which satisfies: 30 μm≤L≤80 μm.

7. The battery according to claim 1, characterized in that The battery cell further includes a positive electrode sheet and a separator, wherein the separator is located between the positive electrode sheet and the negative electrode sheet.

8. The battery according to claim 1, characterized in that The compaction density of the negative electrode sheet is P, which satisfies: 1.6 g / cm 3 ≤P≤1.7g / cm 3 .

9. The battery according to claim 1, characterized in that There are a plurality of grooves, and the plurality of grooves are arranged at intervals along the length direction of the negative electrode sheet.

10. The battery according to claim 9, characterized in that The distance between two adjacent grooves is d, which satisfies: 1.0mm≤d≤2.5mm.

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