Lithium battery

Abstract

The utility model relates to a lithium battery, which comprises: a battery cell, which comprises a positive pole piece and a negative pole piece, the positive pole piece has a first piece surface capacity, the negative pole piece has a second piece surface capacity, the second piece surface capacity is less than the first piece surface capacity, the ratio of the second piece surface capacity to the first piece surface capacity is 0.4-0.6, and the compaction value of the negative pole piece is 1.0 g / cc to 1.5 g / cc; and the peripheral assembly is used for clamping the battery cell and applying pressure to the battery cell. According to the present invention, the second sheet surface capacity is set to be less than the first sheet surface capacity, the ratio of the second sheet surface capacity to the first sheet surface capacity is located in the first preset interval, and the peripheral assembly applies the pressure to the battery cell so as to wind more positive pole pieces and negative pole pieces in the unit volume, such that the volume energy density of the lithium battery is improved. Meanwhile, the peripheral assembly is arranged to apply pressure to the battery cell, and the pressure can inhibit the growth of lithium dendrites in the lithium battery, so that the problem of non-uniform lithium deposition in the lithium metal battery is solved, and the capacity development of the lithium battery is further improved.

Description

Technical Field

[0001] The present application relates to the field of battery technology, and in particular to a lithium battery. Background Art

[0002] With the rapid development of new energy, the demand for high energy density batteries in power batteries and energy storage batteries is becoming stronger and stronger. Among them, lithium batteries are widely used.

[0003] However, the energy density of mature lithium batteries at this stage is far from meeting the demand, and some commercial high-energy-density lithium metal batteries have not been widely used due to the cost and safety issues of lithium metal negative electrodes. Therefore, it is extremely urgent to develop a high-energy-density battery at this stage. Utility Model Content

[0004] Based on this, it is necessary to provide a lithium battery with higher energy density. The present application provides a lithium battery, comprising:

[0005] A battery cell, comprising a positive electrode sheet and a negative electrode sheet, wherein the positive electrode sheet has a first sheet capacity, the negative electrode sheet has a second sheet capacity, the second sheet capacity is less than the first sheet capacity, and the ratio of the second sheet capacity to the first sheet capacity is between 0.4 and 0.6, and the compaction value of the negative electrode sheet is between 1.0 g / cc and 1.5 g / cc;

[0006] The peripheral component clamps the battery core and is used to apply pressure to the battery core.

[0007] In one of the embodiments, the pressure applied by the peripheral component to the battery cell is within a second preset range.

[0008] In one embodiment, the second preset interval includes 500 kPa-1500 kPa.

[0009] In one embodiment, the peripheral component includes a soft clamp, a hard clamp and a pressure piece, the soft clamp clamps the battery core, the hard clamp clamps the soft clamp, and the pressure piece is used to control the pressure of the hard clamp.

[0010] In one embodiment, the soft splint includes a silicone splint, the hard splint includes a metal splint, and the pressure member includes a screw assembly, and the screw assembly passes through the metal splint.

[0011] In one embodiment, the battery cell has a first side and a second side opposite to each other, the hard splint includes a first hard splint and a second hard splint, the soft splint includes a first soft splint and a second soft splint, the first soft splint is located between the first side of the battery cell and the first hard splint, and the second soft splint is located between the second side of the battery cell and the second hard splint.

[0012] In one embodiment, the screw assembly includes a matching screw body and a screw rod, the screw body is located on a surface of the hard clamping plate away from the battery core, and the screw rod penetrates the hard clamping plate and passes through the screw body.

[0013] In one embodiment, the first surface capacity comprises 2 mAh / cm 2 -5mAh / cm 2 .

[0014] In one embodiment, the second surface capacity comprises 0.5 mAh / cm 2 -3.5mAh / cm 2 .

[0015] In one embodiment, the positive electrode active material of the positive electrode plate includes any one or more of lithium cobalt oxide, lithium iron phosphate, lithium manganese phosphate, lithium manganese iron phosphate, lithium manganese oxide, lithium nickel oxide or nickel-cobalt-manganese ternary, and the negative electrode active material of the negative electrode plate includes graphite.

[0016] In the above-mentioned lithium battery, since the second sheet capacity is set to be smaller than the first sheet capacity, and the ratio of the second sheet capacity to the first sheet capacity is between 0.4-0.6, the compaction value of the negative electrode sheet is between 1.0g / cc-1.5g / cc, and the peripheral components apply pressure to the battery cell, so that more positive and negative electrode sheets can be wound in a unit volume, thereby improving the volume energy density of the lithium battery. At the same time, the peripheral components are set to apply pressure to the battery cell, which can inhibit the growth of lithium dendrites in the lithium metal battery, thereby solving the problem of uneven lithium deposition in the lithium metal battery, and then improving the capacity of the lithium battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the conventional technology, the drawings required for use in the embodiments or the conventional technology descriptions are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0018] Figure 1 A schematic diagram of a lithium battery provided by an embodiment;

[0019] Figure 2 A flow chart of a lithium battery preparation method provided by an embodiment;

[0020] Figures 3 to 5 This is a schematic diagram of the test results;

[0021] Figure 6 An image of lithium deposition provided by an embodiment;

[0022] Figure 7 A statistical graph of test results provided by an embodiment.

[0023] Explanation of the reference numerals: lithium battery 100; battery cell 110; peripheral component 120; hard splint 121; first hard splint 1211; second hard splint 1212; soft splint 122; first soft splint 1221; second soft splint 1222; pressure member 123; screw body 1231; screw rod 1232.

[0024] In order to better describe and illustrate the embodiments and / or examples of the utility models disclosed herein, reference may be made to one or more drawings. The additional details or examples used to describe the drawings should not be considered as limiting the scope of any of the disclosed utility models, the embodiments and / or examples currently described, and the best modes of these utility models currently understood. DETAILED DESCRIPTION

[0025] In order to facilitate understanding of the present application, the present application will be described more fully below with reference to the relevant drawings. Embodiments of the present application are provided in the drawings. However, the present application can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present application more thorough and comprehensive.

[0026] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used herein in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application.

[0027] In each embodiment, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in each embodiment can be understood according to the specific situation.

[0028] It is understood that the terms "first", "second", etc. used in this application may be used herein to describe various elements, but these elements are not limited by these terms. These terms are only used to distinguish a first element from another element. For example, without departing from the scope of this application, a first splint may be referred to as a second splint, and similarly, a second splint may be referred to as a first splint. Both the first splint and the second splint are splints, but they are not the same splint.

[0029] It can be understood that the “connection” in the following embodiments should be understood as “electrical connection”, “communication connection”, etc. if the connected circuits, modules, units, etc. have electrical signals or data transmission between each other.

[0030] It should be understood that when an element or layer is referred to as being "on, adjacent to, or connected to" another element or layer, it may be directly on, adjacent to, or connected to the other element or layer, or there may be an intervening element or layer. In contrast, when an element is referred to as being "directly on, directly adjacent to, or directly connected to" another element or layer, there may be no intervening element or layer. It should be understood that although the terms first, second, third, etc. may be used to describe various elements, components, regions, and layers, these elements, components, regions, and layers should not be limited by these terms. These terms are merely used to distinguish one element, component, region, or layer from another element, component, region, or layer. Therefore, without departing from the teachings of the present embodiment, the first element, component, region, or layer discussed below may be represented as a second element, component, region, or layer.

[0031] Spatial relationship terms such as "under", "below", "below", "under", "above", "above", etc., may be used herein to describe the relationship between an element or feature shown in the figures and other elements or features. It should be understood that in addition to the orientations shown in the figures, spatial relationship terms also include different orientations of the device in use and operation. For example, if the device in the accompanying drawings is turned over, the element or feature described as "under other elements" or "under it" or "under it" will be oriented as "on" other elements or features. Therefore, the exemplary terms "under" and "under" may include both upper and lower orientations. In addition, the device may also include additional orientations (e.g., rotated 90 degrees or other orientations), and the spatial descriptors used herein are interpreted accordingly.

[0032] It can be understood that “at least one” means one or more, “plurality” means two or more, and “at least a portion of an element” means a part or all of an element.

[0033] When used herein, the singular forms "a", "an", and "said / the" may also include plural forms, unless the context clearly indicates otherwise. It should also be understood that the terms "include / comprise" or "have" and the like specify the presence of stated features, wholes, steps, operations, components, parts, or combinations thereof, but do not exclude the possibility of the presence or addition of one or more other features, wholes, steps, operations, components, parts, or combinations thereof. At the same time, the term "and / or" used in this specification includes any and all combinations of the relevant listed items.

[0034] When a numerical range is disclosed in this application, the above range is considered to be continuous and includes the minimum and maximum values ​​of the range, as well as every value between such minimum and maximum values. Further, when a range refers to an integer, every integer between the minimum and maximum values ​​of the range is included. In addition, when multiple ranges are provided to describe features or characteristics, the ranges can be combined. In other words, unless otherwise indicated, all ranges disclosed in this application should be understood to include any and all subranges included therein.

[0035] In one embodiment, see Figure 1 , a lithium battery 100 is provided. The lithium battery 100 includes: a battery cell 110 and a peripheral component 120.

[0036] The battery cell 110 includes a positive electrode sheet and a negative electrode sheet. The positive electrode sheet has a first surface capacity, and the negative electrode sheet has a second surface capacity. The second surface capacity is smaller than the first surface capacity, and the ratio (N / P) of the second surface capacity to the first surface capacity is within a first preset range.

[0037] The ratio of the second surface capacity to the first surface capacity can be between 0.4 and 0.6. Of course, in actual products, the N / P ratio can be adjusted within a certain range by controlling the specific values ​​of the second surface capacity and the first surface capacity. As an example, the first surface capacity includes 2 mAh / cm 2 -5mAh / cm 2 The second surface capacity includes 0.5mAh / cm 2 -3.5mAh / cm 2 At this time, the first preset interval, that is, the ratio of the second surface capacity to the first surface capacity, can be 0.3-0.7. Specifically, the first surface capacity can be 3.10 mAh / cm 2 The second surface capacity can be 0.62 mAh / cm 2 (At this time, N / P = 0.2), 1.24mAh / cm 2 (At this time, N / P = 0.4), 1.86 mAh / cm 2(At this time, N / P = 0.6), 2.48 mAh / cm 2 (At this time, N / P = 0.8), 3.44 mAh / cm 2 (At this time, N / P = 1.11).

[0038] The positive electrode active material of the positive electrode plate includes any one or more of lithium cobalt oxide, lithium iron phosphate, lithium manganese phosphate, lithium manganese iron phosphate, lithium manganese oxide, lithium nickel oxide or nickel cobalt manganese ternary, and the negative electrode active material of the negative electrode plate includes graphite, etc. This embodiment does not specifically limit the active materials of the positive electrode plate and the negative electrode plate.

[0039] The compaction value of the negative electrode sheet can be between 1.0 g / cc and 1.5 g / cc. Of course, in actual products, the compaction value of the negative electrode sheet can also be between 0.8 g / cc and 1.7 g / cc. Specifically, the compaction value of the negative electrode sheet can be 1.0 g / cc, 1.2 g / cc, or 1.4 g / cc.

[0040] Of course, the battery cell 110 may also include a diaphragm, an electrolyte, a shell, and a tab. As an example, the diaphragm is located between the positive and negative electrodes of the battery to allow lithium ions in the battery to pass freely between the positive electrode sheet and the negative electrode sheet. The positive electrode sheet, the negative electrode sheet, and the diaphragm can be wound on a laminating machine, injected with electrolyte, and placed in a shell. The shell may be a steel shell, an aluminum shell, or an aluminum-plastic film shell. Among them, the lithium salt of the electrolyte may include, but is not limited to, lithium perchlorate, lithium bis(trifluoromethanesulfonyl imide), lithium hexafluorophosphate, or lithium tetrafluoroborate.

[0041] The peripheral component 120 clamps the battery cell 110 and is used to apply pressure to the battery cell 110. Specifically, the pressure applied by the peripheral component 120 to the battery cell 110 is in a second preset range. As an example, the second preset range includes 500 kPa-1500 kPa.

[0042] Exemplarily, the peripheral assembly 120 includes a hard clamping plate 121, a soft clamping plate 122, and a pressure member 123. The soft clamping plate 122 clamps the battery cell 110, the hard clamping plate 121 clamps the soft clamping plate 122, and the pressure member 123 is used to control the hard clamping plate 121 to apply pressure to the battery cell 110.

[0043] The soft splint 122 includes a silicone splint, which is used to protect the battery cell 110 . The silicone splint can make the pressure on the battery cell 110 more uniform, thereby reducing the risk of short circuit of the battery cell 110 .

[0044] The hard clamping plate 121 includes a metal clamping plate. For example, the material of the hard clamping plate 121 can be iron, copper or aluminum.

[0045] The pressure member 123 may be a screw assembly, which includes a screw body 1231 and a screw rod 1232. The screw rod 1232 penetrates the metal clamping plate. The screw body 1231 is located on the surface of the hard clamping plate 121 away from the battery cell 110, and the screw rod 1232 penetrates the hard clamping plate 1221 and the screw body 1231. It can be understood that by rotating the screw body 1231 in the screw assembly, the purpose of regulating the hard clamping plate 121 to apply pressure to the battery cell 110 is achieved.

[0046] For details, please refer to Figure 1 The hard clamping plate 121 may include a first hard clamping plate 1211 and a second hard clamping plate 1212, and the soft clamping plate 122 may include a first soft clamping plate 1221 and a second soft clamping plate 1222, wherein the first soft clamping plate 1221 is located between the first surface of the battery cell 110 and the first hard clamping plate 121, and the second soft clamping plate 1222 is located between the second surface of the battery cell 110 and the second hard clamping plate 121. The first surface of the battery cell 110 and the second surface of the battery cell 110 are two opposite surfaces.

[0047] Each screw rod 1232 penetrates the first hard clamping plate 121 and the second hard clamping plate 121, and the screw body 1231 is located on the surface of at least one of the first hard clamping plate 121 or the second hard clamping plate 121 away from the battery cell 110. At the same time, each screw rod 1232 passes through the screw body 1231. It can be understood that by rotating the screw body 1231, the screw body 1231 moves on the screw rod 1232, so as to achieve the purpose of controlling the relative distance between the first hard clamping plate 121 and the second hard clamping plate 121, and finally controlling the pressure applied by the peripheral component 120 to the battery cell 110.

[0048] Of course, the peripheral component 120 can also be in other forms. For example, the peripheral component 120 can also surround the battery cell 110, etc. There can be one pressure member 123, or there can be multiple pressure members 123, and the multiple pressure members 123 can be symmetrically arranged to uniformly control the pressure applied by the peripheral component 120 to the battery cell 110. When the lithium battery 100 is placed on a device such as a desktop, an elastic component such as a spring can be provided between the pressure member 123 and the desktop to protect the desktop.

[0049] In this embodiment, by setting the second sheet capacity to be smaller than the first sheet capacity, and the ratio of the second sheet capacity to the first sheet capacity to be between 0.4-0.6, the compaction value of the negative electrode sheet is between 1.0g / cc-1.5g / cc, so that more positive and negative electrode sheets can be wound in a unit volume, thereby improving the volume energy density of the lithium battery 100. In addition, setting the second sheet capacity to be smaller than the first sheet capacity can also reduce the manufacturing cost of the lithium battery 100.

[0050] At the same time, in this embodiment, a peripheral component 120 is provided to apply pressure to the battery cell 110 , so that when the lithium battery 100 is charged and discharged, the pressure can suppress the growth of lithium dendrites in the lithium battery 100 , thereby solving the problem of uneven lithium deposition in the lithium metal battery, and further improving the capacity of the lithium battery 100 .

[0051] Based on the same utility model concept, please refer to Figure 2 In one embodiment, a method for preparing a lithium battery 100 is provided, comprising the following steps:

[0052] Step S100: providing a positive electrode sheet and a negative electrode sheet, wherein the positive electrode sheet has a first surface capacity and the negative electrode sheet has a second surface capacity, wherein the second surface capacity is smaller than the first surface capacity and the ratio of the second surface capacity to the first surface capacity is within a first preset range.

[0053] Step S200: preparing a battery cell 110 using a positive electrode sheet and a negative electrode sheet.

[0054] Step S300 : preparing the peripheral component 120 , and the peripheral component 120 clamps the battery cell 110 to apply pressure to the battery cell 110 .

[0055] In step S100 to step S300, when preparing the battery cell 110, the positive electrode sheet, the negative electrode sheet and the separator can be wound on a laminating machine, injected with electrolyte, and placed in a shell. This embodiment does not limit the specific composition of the separator, electrolyte and shell.

[0056] It should be understood that although Figure 2 The steps in the flowchart are shown in sequence as indicated by the arrows, but these steps are not necessarily executed in the order indicated by the arrows. Unless otherwise specified in this document, there is no strict order restriction for the execution of these steps, and these steps can be executed in other orders. Moreover, Figure 2 At least part of the steps may include multiple steps or multiple stages. These steps or stages are not necessarily performed at the same time, but can be performed at different times. The execution order of these steps or stages is not necessarily sequential, but can be performed in turn or alternately with other steps or at least part of the steps or stages in other steps.

[0057] See also Figures 3 to 6 In order to further illustrate the effect of the technical solution of this embodiment, the following experimental data is analyzed and the present application is described in combination with specific embodiments and comparative examples. It should be noted that these embodiments are merely descriptive and do not limit the present application in any way.

[0058] Example 1

[0059] The preparation process of the positive electrode sheet is as follows: the positive electrode active material LiCoO 2 , conductive agent carbon black KS-6, and binder polyvinylidene fluoride (PVDF) were mixed in a mass ratio of 97:1:2, and solvent N-methylpyrrolidone (NMP) was added and stirred until the system was uniform to obtain positive electrode slurry. The positive electrode slurry was then evenly coated on the positive electrode current collector aluminum foil by a coating machine, and then rolled / die-cut to obtain LiCoO 2 The positive electrode sheet is designed to have a surface capacity of 3.1 mAh / cm 2 .

[0060] The preparation process of the negative electrode sheet is as follows: the negative electrode active material graphite, conductive agent conductive carbon black (SP), binder sodium carboxymethyl cellulose (CMC) and styrene butadiene rubber (SBR) are mixed in a mass ratio of 95.8:1:1.2:2, and solvent water is added and stirred until the system is uniform to obtain the negative electrode slurry. The negative electrode slurry is then evenly coated on the negative electrode current collector copper foil by a coating machine, and then rolled / die-cut to obtain a graphite negative electrode sheet. The negative electrode sheet surface capacity is 1.86 mAh / cm 2 , compaction is 1.5 g / cc, N / P= 0.6.

[0061] The process of preparing the battery is as follows: using the above-mentioned positive electrode sheets and negative electrode sheets, a stacking machine is used in a dry room (dew point -60°C) to stack 2Ah battery cells.

[0062] The battery test process is: the battery cell is tested at a charge and discharge current density of 1C / 1C and a voltage range of 3.25V-4.45V. The test temperature is 25°C, and the pressure applied to the battery cell by the peripheral components is controlled to be 300 kPa.

[0063] Example 2

[0064] The specific preparation process can refer to the preparation in Example 1, except that the compaction value of the negative electrode sheet is 1.4 g / cc.

[0065] Example 3

[0066] The specific preparation process can refer to the preparation in Example 1, except that the compaction value of the negative electrode sheet is 1.2 g / cc.

[0067] Example 4

[0068] The specific preparation process can refer to the preparation in Example 1, except that the compaction value of the negative electrode plate is 1.0 g / cc.

[0069] Example 5

[0070] The specific preparation process can refer to the preparation in Example 1, except that the surface capacity of the negative electrode sheet is 1.24 mAh / cm 2 , compaction is 1.5 g / cc, N / P = 0.4.

[0071] Example 6

[0072] The specific preparation process can refer to the preparation in Example 1, except that the surface capacity of the negative electrode sheet is 1.24 mAh / cm 2 , compaction is 1.4 g / cc, N / P = 0.4.

[0073] Example 7

[0074] The specific preparation process can refer to the preparation in Example 1, except that the surface capacity of the negative electrode sheet is 1.24 mAh / cm 2 , compaction is 1.2 g / cc, N / P = 0.4.

[0075] Example 8

[0076] The specific preparation process can refer to the preparation in Example 1, except that the surface capacity of the negative electrode sheet is 1.24 mAh / cm 2 , compaction is 1.0 g / cc, N / P = 0.4.

[0077] Comparative Example 1

[0078] The specific preparation process can refer to the preparation in Example 1, except that the surface capacity of the negative electrode sheet is 3.44 mAh / cm 2 , compaction is 1.5 g / cc, N / P = 1.11.

[0079] Comparative Example 2

[0080] The specific preparation process can refer to the preparation in Example 1, except that the compaction value of the negative electrode plate is 1.2 g / cc, and the pressure applied to the battery cell by the peripheral components is controlled to be 1000 kPa.

[0081] The test results of the above embodiments and comparative examples are summarized in Figure 7 middle.

[0082] See also Figures 3 to 7 The test results show that, firstly, from the data in Examples 1-8 and Comparative Examples 1-2, it can be seen that the energy density of the battery cell can be increased by reducing the N / P value, and in particular, the volume energy density of the battery cell can be increased by reducing the N / P value.

[0083] At the same time, it can be seen from the data in Examples 1-4 or Examples 5-8 that the design of the high-voltage solid electrode can improve the volume energy density of the battery cell. Figure 7 Examples 1-4 and Figure 3 The lithium battery in Example 3 (i.e., when N / P = 0.6 and compacted to 1.2 g / cc) has a maximum capacity when the number of cycles is the largest, indicating that the performance of the lithium battery is better.

[0084] Moreover, refer to Figure 7 Examples 5-8 and Figure 4 It can be seen that the lithium battery in Example 8 (i.e., when N / P = 0.4 and compacted to 1.0 g / cc) has the largest capacity when the number of cycles is the largest, indicating that the performance of the lithium battery is better.

[0085] Reference Figure 7 Example 3, Comparative Example 2 and Figure 5 It can be seen that when a greater pressure is applied to a lithium battery, the capacity of the battery is the largest when the number of cycles is the largest, that is, applying pressure to a lithium battery can significantly improve the capacity of the battery.

[0086] The applicant has found that by reducing the N / P value, more positive and negative electrode sheets can be wound in a unit volume, thereby increasing the volume energy density of the lithium battery. In addition, setting the second sheet capacity to be smaller than the first sheet capacity can also reduce the manufacturing cost of the lithium battery.

[0087] At the same time, the applicant also found that by setting a peripheral component to apply pressure to the battery cell, the greater the pressure, the more it can inhibit the growth of lithium dendrites in the lithium battery when the lithium battery is charged and discharged, thereby solving the problem of uneven lithium deposition in the lithium metal battery and further improving the capacity of the lithium battery.

[0088] In addition, refer to Figure 6 , under N / P = 0.6, the battery was charged to a state of charge (SOC) of 65%, and the lithium deposition was observed. The graphite surface of the lithium battery with a compaction of 1.0g / cc has less deposited lithium, and the low compaction and high porosity negative electrode sheet can be obtained. When the battery is operated in lithium metal mode, lithium can be deposited in the gaps, reducing the contact between the deposited lithium and the electrolyte, thereby improving the battery performance.

[0089] It can be understood that the above-mentioned lithium battery can also adopt other forms, not limited to the forms mentioned in the above embodiments, as long as it can achieve the function of the lithium battery.

[0090] In the description of this specification, the description with reference to the terms "some embodiments", "other embodiments", etc. 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 application. In this specification, the schematic description of the above terms does not necessarily refer to the same embodiment or example.

[0091] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0092] The above-described embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the present application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the attached claims.

[0093] It is obvious to those skilled in the art that the present application is not limited to the details of the exemplary embodiments described above, and that the present application can be implemented in other specific forms without departing from the spirit or essential features of the present application. Therefore, the embodiments should be regarded as exemplary and non-limiting in all respects, and the scope of the present application is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims be included in the present application. Any reference numeral in a claim should not be regarded as limiting the claim to which it relates.

Claims

1. A lithium battery, characterized in that: The lithium battery comprises: A battery cell, comprising a positive electrode sheet and a negative electrode sheet, wherein the positive electrode sheet has a first sheet capacity, the negative electrode sheet has a second sheet capacity, the second sheet capacity is less than the first sheet capacity, and the ratio of the second sheet capacity to the first sheet capacity is between 0.4 and 0.6, and the compaction value of the negative electrode sheet is between 1.0 g / cc and 1.5 g / cc; The peripheral component clamps the battery core and is used to apply pressure to the battery core.

2. The lithium battery according to claim 1, characterized in that: The pressure applied by the peripheral component to the battery cell is within a second preset range.

3. The lithium battery according to claim 2, characterized in that: The second preset interval includes 500 kPa-1500 kPa.

4. The lithium battery according to claim 1, characterized in that The peripheral component includes a soft clamping plate, a hard clamping plate and a pressure piece, the soft clamping plate clamps the battery core, the hard clamping plate clamps the soft clamping plate, and the pressure piece is used to control the pressure of the hard clamping plate.

5. The lithium battery according to claim 4, characterized in that: The soft splint includes a silicone splint, the hard splint includes a metal splint, and the pressure member includes a screw assembly, and the screw assembly passes through the metal splint.

6. The lithium battery according to claim 5, characterized in that: The battery cell has a first surface and a second surface opposite to each other, the hard splint includes a first hard splint and a second hard splint, the soft splint includes a first soft splint and a second soft splint, the first soft splint is located between the first surface of the battery cell and the first hard splint, and the second soft splint is located between the second surface of the battery cell and the second hard splint.

7. The lithium battery according to claim 5, characterized in that: The screw assembly comprises a matched screw body and a screw rod, the screw body is located on the surface of the hard clamping plate away from the battery core, and the screw rod penetrates the hard clamping plate and passes through the screw body.

8. The lithium battery according to claim 1, characterized in that: The first surface capacity includes 2 mAh / cm 2 -5mAh / cm 2 .

9. The lithium battery according to claim 1, characterized in that: The second surface capacity includes 0.5 mAh / cm 2 -3.5mAh / cm 2 .

10. The lithium battery according to claim 1, characterized in that: The positive electrode active material of the positive electrode plate includes any one or more of lithium cobalt oxide, lithium iron phosphate, lithium manganese phosphate, lithium manganese iron phosphate, lithium manganese oxide, lithium nickel oxide or nickel-cobalt-manganese ternary, and the negative electrode active material of the negative electrode plate includes graphite.

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