Battery cell, battery device and energy storage device

Abstract

The utility model discloses a battery monomer, battery device and energy storage device, relates to battery technical field, battery monomer includes: electrode subassembly, positive pole leading-out piece, negative pole leading-out piece, package bag and electrolyte, electrode subassembly is equipped with positive pole ear and negative pole ear, package bag wraps the electrode subassembly, at least one end of package bag is equipped with the sealed edge, and the sealed edge is equipped with the positive pole ear and the negative pole ear. A space between one side, extending out of the tab, of the electrode assembly and the sealing edge is a leading-out area; and the area of the lead-out region of the unit capacity of the battery monomer meets the interval of 18mm < 2 > / Ah to 28mm < 2 > / Ah. By designing the area of the lead-out region in the single battery, the area of the lead-out region in the single battery is in a reasonable range, so that the quantity of electrolyte in the single battery is increased; and meanwhile, the risk that the energy density of the battery monomer is reduced due to the fact that the lead-out area occupies the space for arranging the active material and the electrode assembly in the packaging bag is reduced, so that the energy density of the battery monomer can meet the use requirement.

Description

Technical Field

[0001] The utility model relates to the technical field of batteries, in particular to a battery monomer, a battery device and an energy storage device. Background Art

[0002] In recent years, new energy vehicles have experienced rapid development. In the electric vehicle sector, batteries, as the power source of electric vehicles, play an irreplaceable and important role. As core components of new energy vehicles, batteries have high requirements in terms of both energy density and service life.

[0003] In the related art, the electrolyte of the battery cell is consumed too quickly, resulting in a short service life of the battery cell and easily causing poor stability of the battery cell in the later stages of the cycle, thereby causing the battery cell to suddenly accelerate attenuation. Utility Model Content

[0004] The present invention aims to solve at least one of the technical problems in the prior art. To this end, the present invention provides a battery cell having a long service life and good stability.

[0005] The first objective of the present application is to provide a battery cell.

[0006] The second objective of this application is to provide a battery device.

[0007] The third objective of this application is to provide an energy storage device.

[0008] In the first aspect, the present application proposes a battery cell, comprising: an electrode assembly, the electrode assembly being provided with a positive electrode ear and a negative electrode ear; a positive electrode lead-out sheet and a negative electrode lead-out sheet, the positive electrode lead-out sheet being electrically connected to the positive electrode ear, and the negative electrode lead-out sheet being electrically connected to the negative electrode ear; a packaging bag, the packaging bag wrapping the electrode assembly, at least one end of the packaging bag being provided with an edge seal, the positive electrode lead-out sheet and the negative electrode lead-out sheet respectively extending out of the packaging bag from the edge seal, and the space between one side of the electrode assembly extending from the electrode ear and the edge seal being the lead-out area; an electrolyte, the electrolyte being filled between the electrode assembly and the packaging bag; the area of the lead-out area per unit capacity of the battery cell satisfies the interval of 18mm 2 / Ah-28mm 2 / Ah.

[0009] In the above technical solution, the area of the lead-out region in the battery cell is designed so that the area of the lead-out region in the battery cell is within a reasonable range, which is beneficial to increasing the amount of electrolyte in the battery cell. At the same time, it is beneficial to reduce the risk of reduced energy density of the battery cell due to the lead-out region occupying the space in the packaging bag for arranging active materials and electrode assemblies, so as to increase the service life of the battery cell while ensuring that the energy density of the battery cell can meet the usage requirements.

[0010] According to some embodiments of the present application, the electrolyte injection coefficient satisfies: 2.7g / Ah-3.5g / Ah.

[0011] In the above technical solution, by designing the electrolyte injection coefficient, it is beneficial to increase the service life of the battery cell and at the same time it is beneficial to make the energy density of the battery cell meet the use requirements.

[0012] According to some embodiments of the present application, in a first direction, the minimum dimension of the lead-out area is H, the length of the packaging bag is L, and the ratio of the minimum dimension H of the lead-out area to the length L of the packaging bag ranges from 3.6 percent to 5.6 percent, and the first direction is the direction in which the electrode assembly extends out of the electrode tab.

[0013] In the above technical solution, the length of the packaging bag and the minimum size of the lead-out area in the first direction are designed in a correlated manner to reserve sufficient space for the electrolyte in the packaging bag, thereby improving the cycle performance and service life of the electrode assembly, while reducing the risk of the lead-out area excessively occupying the space used to arrange active materials and electrode assemblies, thereby reducing the risk of a decrease in the energy density of the electrode assembly.

[0014] According to some embodiments of the present application, the ratio of the minimum dimension H of the lead-out area to the length L of the packaging bag ranges from 4.4 percent to 5.2 percent.

[0015] In the above technical solution, by further correlating the length of the packaging bag with the minimum size of the lead-out area in the first direction, sufficient space is reserved for the electrolyte in the packaging bag, thereby further improving the cycle performance and service life of the electrode assembly. At the same time, it is beneficial to further reduce the risk of the lead-out area excessively occupying the space used to arrange active materials and electrode assemblies, thereby reducing the risk of a decrease in the energy density of the electrode assembly.

[0016] According to some embodiments of the present application, in a first direction, the positive electrode tab is provided at one end of the electrode assembly and the negative electrode tab is provided at the other end, the lead-out area includes a first lead-out area and a second lead-out area located at both ends of the electrode assembly, the minimum dimension of the first lead-out area in the first direction is H1, the minimum dimension of the second lead-out area in the first direction is H2, the minimum dimension of the lead-out area in the first direction is H, and the minimum dimension H of the lead-out area is the sum of the minimum dimension H1 of the first lead-out area in the first direction and the minimum dimension H2 of the second lead-out area in the first direction; wherein, the first direction is the direction in which the electrode assembly extends out of the electrode tab.

[0017] In the above technical solution, the positive electrode ear and the negative electrode ear are respectively arranged at the two ends of the electrode assembly in the first direction to increase the distance between the positive electrode ear and the negative electrode ear, thereby reducing the risk of short circuit in the electrode assembly. Based on the structure of setting the positive electrode ear and the negative electrode ear at both ends of the electrode assembly, the first lead-out area and the second lead-out area are respectively arranged at the two ends of the electrode assembly, so that the positive lead-out sheet and the negative lead-out sheet can be extended from the packaging bag, which is conducive to the electrolyte to evenly infiltrate the electrode assembly, thereby improving the performance of the electrode assembly.

[0018] According to some embodiments of the present application, in the first direction, the length of the packaging bag is L, and the ratio of the minimum dimension H1 of the first lead-out area in the first direction to the length L of the packaging bag is in a range of 1.8 percent to 2.8 percent; and / or in the first direction, the length of the packaging bag is L, and the ratio of the minimum dimension H2 of the second lead-out area in the first direction to the length L of the packaging bag is in a range of 1.8 percent to 2.8 percent.

[0019] In the above technical solution, by correlating the size of the first lead-out area in the first direction with the length of the packaging bag, the space occupied by the first lead-out area in the packaging bag is reasonably allocated, which is beneficial to improving the wetting effect of the electrolyte on the end of the electrode assembly provided with the positive electrode ear, and at the same time helps to reduce the risk of insufficient space for arranging other components in the packaging bag due to the excessive size of the first lead-out area; by correlating the size of the second lead-out area in the first direction with the length of the packaging bag, the space occupied by the second lead-out area in the packaging bag is reasonably allocated, which is beneficial to improving the wetting effect of the electrolyte on the end of the electrode assembly provided with the negative electrode ear, and at the same time helps to reduce the risk of insufficient space for arranging other components in the packaging bag due to the excessive size of the second lead-out area.

[0020] According to some embodiments of the present application, the minimum dimension H1 of the first lead-out area in the first direction ranges from 10.8 mm to 16.8 mm; and / or the minimum dimension H2 of the second lead-out area in the first direction ranges from 10.6 mm to 16.8 mm.

[0021] In the above technical solution, by designing the minimum dimension H1 of the first lead-out area in the first direction, it is beneficial to improve the wetting effect of the electrolyte on the end of the electrode assembly provided with the positive electrode ear, and at the same time it is beneficial to reduce the risk of insufficient space for arranging the remaining components in the packaging bag due to the excessive size of the first lead-out area; by designing the minimum dimension H2 of the second lead-out area in the first direction, it is beneficial to improve the wetting effect of the electrolyte on the end of the electrode assembly provided with the negative electrode ear, and at the same time it is beneficial to reduce the risk of insufficient space for arranging the remaining components in the packaging bag due to the excessive size of the second lead-out area.

[0022] According to some embodiments of the present application, in the first direction, the length of the packaging bag is L, and the ratio of the minimum dimension H1 of the first lead-out area in the first direction to the length L of the packaging bag is in a range of 2.2 percent to 2.6 percent; and / or in the first direction, the length of the packaging bag is L, and the ratio of the minimum dimension H2 of the second lead-out area in the first direction to the length L of the packaging bag is in a range of 2.2 percent to 2.6 percent.

[0023] In the above technical solution, by further correlating the size of the first lead-out area in the first direction and the length of the packaging bag, the space occupied by the first lead-out area in the packaging bag is further reasonably allocated, thereby improving the wetting effect of the electrolyte on the electrode assembly while preventing the size of the first lead-out area from being too large and encroaching on the layout space of the electrode assembly; by further correlating the size of the second lead-out area in the first direction and the length of the packaging bag, the space occupied by the second lead-out area in the packaging bag is further reasonably allocated, thereby improving the wetting effect of the electrolyte on the electrode assembly while preventing the size of the second lead-out area from being too large and encroaching on the layout space of the electrode assembly and the active material.

[0024] According to some embodiments of the present application, a ratio of a minimum dimension H1 of the first lead-out area in the first direction to a minimum dimension H2 of the second lead-out area in the first direction ranges from 0.9 to 1.1.

[0025] In the above technical solution, by designing the minimum dimension H1 of the first lead-out area in the first direction in a correlation with the minimum dimension H2 of the second lead-out area in the first direction, it is beneficial to make the size of the first lead-out area close to the size of the second lead-out area, thereby making the amount of electrolyte distributed at both ends of the electrode assembly in the first direction similar, thereby facilitating uniform infiltration of the electrolyte into the electrode assembly, and facilitating improving the efficiency of the electrolyte infiltration from the two ends of the electrode assembly to the middle position of the electrode assembly.

[0026] According to some embodiments of the present application, the battery cell satisfies: a ratio of a minimum dimension H1 of the first lead-out area in the first direction to a minimum dimension H2 of the second lead-out area in the first direction ranges from 0.95 to 1.05.

[0027] In the above technical solution, by further designing the correlation between the minimum size H1 of the first lead-out area in the first direction and the minimum size H2 of the second lead-out area in the first direction, it is beneficial to further make the size of the first lead-out area close to the size of the second lead-out area, thereby making the amount of electrolyte distributed at both ends of the electrode assembly in the first direction similar, thereby facilitating uniform infiltration of the electrolyte into the electrode assembly, and improving the efficiency of the electrolyte infiltration from the two ends of the electrode assembly to the middle position of the electrode assembly.

[0028] According to some embodiments of the present application, the electrode assembly is a laminated electrode assembly and includes a positive electrode sheet and a negative electrode sheet, the positive electrode sheet is provided with the positive electrode ear, the negative electrode sheet is provided with the negative electrode ear, the active material of the positive electrode sheet is lithium iron phosphate, and the porosity of the active material layer of the negative electrode sheet ranges from twenty percent to thirty-five percent.

[0029] In the above technical solution, by designing the porosity of the active material layer of the negative electrode sheet, it is beneficial to improve the electrolyte infiltration effect on the negative electrode sheet and the liquid retention effect of the negative electrode sheet, thereby helping to increase the service life of the electrode assembly, and further helping to increase the service life of the battery cell. At the same time, it is beneficial to prevent the compaction density of the electrode assembly from being reduced due to the excessive porosity of the negative electrode sheet, thereby helping to increase the loading amount of the active material of the electrode assembly, and further helping to increase the energy density of the battery cell.

[0030] According to some embodiments of the present application, the porosity of the active material layer of the negative electrode sheet ranges from 20 percent to 35 percent.

[0031] In the above technical solution, by further designing the porosity of the active material layer of the negative electrode sheet, it is beneficial to further improve the electrolyte infiltration effect on the negative electrode sheet and the liquid retention effect of the negative electrode sheet, thereby helping to increase the service life of the electrode assembly, and then helping to increase the service life of the battery cell. At the same time, it is beneficial to increase the compaction density of the electrode assembly, thereby helping to increase the loading amount of the active material of the electrode assembly, and then helping to increase the energy density of the battery cell.

[0032] According to some embodiments of the present application, the electrolyte comprises dimethyl carbonate or ethyl carbonate.

[0033] In the above technical solution, by designing the composition of the electrolyte, it is beneficial to reduce the viscosity of the electrolyte and improve the wetting effect of the electrolyte on the electrode assembly, thereby improving the cycle performance of the electrode assembly.

[0034] According to some embodiments of the present application, the length of the packaging bag in the first direction is L, the width in the second direction is W, and the thickness in the third direction is T, and the packaging bag meets the range of: 550mm≤L≤650mm, 100mm≤W≤140mm, 12mm≤T≤40mm; wherein the third direction is arranged perpendicular to the first direction and the second direction, respectively.

[0035] In the above technical solution, the size of the packaging bag is designed so that there is enough space inside the packaging bag for arranging the lead-out area, electrode assembly and active materials, which is beneficial to extending the service life of the battery cell and improving the energy density of the battery cell.

[0036] In a second aspect, the present application provides a battery device comprising a plurality of the above-mentioned battery cells.

[0037] The advantages of the battery device are the same as those of the aforementioned battery cell, which will not be described in detail here.

[0038] In a third aspect, the present application proposes an energy storage device, which includes the above-mentioned battery cell or the above-mentioned battery device, and the battery cell or the battery device is used to store or provide electrical energy.

[0039] The energy storage device has the same advantages as the above-mentioned battery cell or the above-mentioned battery device, which will not be described in detail here.

[0040] Additional aspects and advantages of the present invention will be given in part in the following description and will become apparent from the following description or learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0042] Figure 1 This is a schematic structural diagram of the energy storage device described in an embodiment of the present application;

[0043] Figure 2 This is a schematic structural diagram of the battery device according to an embodiment of the present application;

[0044] Figure 3 This is a schematic structural diagram of a battery cell according to some embodiments of the present application;

[0045] Figure 4 Schematic diagram of the structure of battery cells according to other embodiments of the present application;

[0046] Figure 5 This is a schematic structural diagram of a battery cell according to an embodiment of the present application.

[0047] Reference numerals:

[0048] Battery cell 100,

[0049] Electrode assembly 110, positive electrode lead sheet 111, negative electrode lead sheet 112,

[0050] Packaging bag 120, edge sealing 121,

[0051] Lead-out area 122, first lead-out area 1221, second lead-out area 1222,

[0052] Battery device 200, housing 210, first housing 211, second housing 212,

[0053] Energy storage device 1000 and control unit 300. DETAILED DESCRIPTION

[0054] To make the purpose, technical solutions, and advantages of the embodiments of this application more clear, the technical solutions in the embodiments of this application will be clearly described below in conjunction with the drawings in the embodiments of this application. Obviously, the described embodiments are part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0055] Unless otherwise defined, all technical and scientific terms used in this application have the same meanings as commonly understood by those skilled in the art to which this application belongs. The terms used in the specification of this application are for the purpose of describing specific embodiments only and are not intended to limit this application. The terms "including" and "having" and any variations thereof in the specification and claims of this application and the above-mentioned drawings are intended to cover non-exclusive inclusions. The terms "first" and "second" in the specification and claims of this application or the above-mentioned drawings are used to distinguish different objects, rather than to describe a specific order or a primary-secondary relationship.

[0056] References to "embodiments" in this application mean that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment of the application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute an independent or alternative embodiment that is mutually exclusive of other embodiments.

[0057] In the description of this application, it should be noted that, unless otherwise specified or limited, the terms "mounted," "connected," "connected," and "attached" should be understood broadly. For example, they can refer to direct connection or indirect connection through an intermediary. Those skilled in the art will understand the specific meanings of these terms in this application based on specific circumstances.

[0058] The term "and / or" in this application simply describes an association between related objects, indicating that three possible relationships exist. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " in this application generally indicates that the related objects are in an "or" relationship.

[0059] In the embodiments of this application, the same reference numerals represent the same components, and for the sake of brevity, detailed descriptions of the same components in different embodiments are omitted. It should be understood that the thickness, length, width, and other dimensions of the various components in the embodiments of this application, as well as the overall thickness, length, width, and other dimensions of the integrated device shown in the drawings are merely illustrative and should not constitute any limitation on this application.

[0060] The term "plurality" used in this application refers to two or more (including two).

[0061] In this application, battery cells may include lithium-ion secondary batteries, lithium-ion primary batteries, lithium-sulfur batteries, sodium-lithium-ion batteries, sodium-ion batteries, or magnesium-ion batteries, and the embodiments of this application are not limited thereto. Battery cells may be cylindrical, flat, rectangular, or in other shapes, and the embodiments of this application are not limited thereto.

[0062] For example, a battery cell typically includes a packaging bag, a laminated battery cell, and an electrolyte. The packaging bag is used to hold the laminated battery cell, and at least one tab extends from the packaging bag. The laminated battery cell includes one or more electrode assemblies, which are formed by a positive electrode sheet, a negative electrode sheet, and a separator. The battery cell primarily operates by the movement of metal ions between the positive and negative electrode sheets.

[0063] A positive electrode sheet generally includes a current collector and a positive electrode active material layer. The positive electrode active material layer is directly or indirectly coated on the positive electrode current collector. The current collector not coated with the positive electrode active material layer protrudes from the current collector coated with the positive electrode active material layer, and the current collector not coated with the positive electrode active material layer serves as the positive electrode tab. Taking lithium-ion batteries as an example, the positive electrode current collector can be made of aluminum, and the positive electrode active material can be lithium cobalt oxide, lithium iron phosphate, ternary lithium, or lithium manganese oxide, etc.

[0064] A negative electrode sheet generally includes a current collector and a negative active material layer. The negative active material layer is directly or indirectly coated on the current collector. The current collector uncoated with the negative active material layer protrudes from the current collector coated with the negative active material layer. The current collector uncoated with the negative active material layer serves as the negative electrode tab. The negative electrode current collector can be made of copper, and the negative active material can be carbon, silicon, or other materials. To ensure that high currents can pass without melting, multiple positive tabs are stacked together, and multiple negative tabs are stacked together.

[0065] The material of the separator is not limited, for example, it can be polypropylene or polyethylene, etc. In recent years, new energy batteries have been increasingly used in life and industry. For example, new energy batteries are increasingly used in the field of energy storage.

[0066] In the related art, the electrolyte of the battery cell is consumed too quickly, resulting in a short service life of the battery cell and easily causing poor stability of the battery cell in the later stages of the cycle, thereby causing the battery cell to suddenly accelerate attenuation.

[0067] Based on the above considerations, in order to improve the service life of a battery cell, a battery cell is proposed, which includes: an electrode assembly, a positive lead-out sheet, a negative lead-out sheet, a packaging bag and an electrolyte. The electrode assembly is provided with a positive electrode ear and a negative electrode ear, the positive electrode lead-out sheet is electrically connected to the positive electrode ear, and the negative electrode lead-out sheet is electrically connected to the negative electrode ear. The packaging bag wraps the electrode assembly, and at least one end of the packaging bag is provided with a sealed edge. The positive electrode lead-out sheet and the negative electrode lead-out sheet extend out of the packaging bag from the sealed edge respectively. The space between one side of the electrode assembly extending from the electrode ear and the sealed edge is the lead-out area, and part of the electrolyte is filled between the electrode assembly and the packaging bag; the area of the lead-out area per unit capacity of the battery cell meets the interval of 18mm 2 / Ah-25mm 2 / Ah.

[0068] In the above technical solution, the area of the lead-out region in the battery cell is designed so that the area of the lead-out region in the battery cell is within a reasonable range, which is beneficial to increasing the amount of electrolyte in the battery cell and reducing the risk of reduced energy density of the battery cell due to the lead-out region occupying the space in the packaging bag for arranging the electrode assembly, so as to increase the service life of the battery cell while ensuring that the energy density of the battery cell can meet the usage requirements.

[0069] The battery device provided in the embodiments of the present application includes the above-mentioned battery cells. The battery device can be used, but is not limited to, in energy storage power supply systems, vehicles, ships, aircraft, and other electrical devices.

[0070] An embodiment of the present application provides an energy storage device for storing electrical energy and capable of providing electrical energy using the above-mentioned battery device. The energy storage device may include but is not limited to an energy storage container, an energy storage cabinet, etc.

[0071] In the following embodiments, for ease of description, the energy storage device 1000 of some embodiments of the present application is taken as an example for description, which will be described below with reference to the accompanying drawings.

[0072] Please refer to Figure 1 , Figure 1 This is a simplified structural diagram of the energy storage device 1000 provided in some embodiments of the present application. The energy storage device 1000 may be an energy storage container or an energy storage cabinet. Figure 1 As shown, the energy storage device 1000 may include a battery device 200 and a control unit 300. The control unit 300 is used to control the charging and discharging of the battery device 200 to ensure the normal operation of the battery device 200. For example, the control unit 300 can be used to monitor environmental parameters such as temperature and humidity.

[0073] Please refer to Figure 2 , Figure 2 Schematic diagram of the structure of the battery device 200 provided for some embodiments of the present application. The battery device 200 includes a case 210 and a battery cell 100, and the battery cell 100 is accommodated in the case 210. The case 210 is used to provide an assembly space for the battery cell 100, and the case 210 can adopt a variety of structures. In some embodiments, the case 210 may include a first case 211 and a second case 212, and the first case 211 and the second case 212 cover each other, and the first case 211 and the second case 212 jointly define a receiving cavity for receiving the battery cell. The second case 212 may be a hollow structure with one end open, and the first case 211 may be a plate-like structure, and the first case 211 covers the open side of the second case 212, so that the first case 211 and the second case 212 jointly define a receiving cavity; or, the first case 211 and the second case 212 may also be hollow structures with one side open (for example Figure 2As shown in FIG, the open side of the first box body 211 is covered with the open side of the second box body 212. Of course, the box body 210 formed by the first box body 211 and the second box body 212 can be in various shapes, such as a cylinder or a cuboid.

[0074] In the battery device 200, multiple battery cells 100 can be connected in series, in parallel, or in a hybrid configuration. A hybrid configuration refers to a combination of series and parallel connections among the multiple battery cells 100. Multiple battery cells 100 can be directly connected in series, in parallel, or in a hybrid configuration, and then housed within the housing 210. Alternatively, the battery device 200 can be a battery module composed of multiple battery cells 100 connected in series, in parallel, or in a hybrid configuration. The battery device 200 can also include other structures, such as a busbar for electrically connecting the multiple battery cells 100.

[0075] Please refer to Figure 3 and Figure 4 , Figure 3 This is a schematic structural diagram of a battery cell 100 provided in some embodiments of the present application. Figure 4 Schematic diagram of the structure of a battery cell 100 provided for other embodiments of the present application. In some embodiments of the present application, the battery cell 100 includes: an electrode assembly 110, a positive electrode lead-out sheet 111, a negative electrode lead-out sheet 112, a packaging bag 120 and an electrolyte. The electrode assembly 110 is provided with a positive electrode ear and a negative electrode ear. The packaging bag 120 wraps the electrode assembly 110. At least one end of the packaging bag 120 is provided with a sealing edge 121. The positive electrode lead-out sheet 111 and the negative electrode lead-out sheet 112 extend out of the packaging bag 120 from the sealing edge 121 respectively. The space between one side of the extending electrode ear of the electrode assembly 110 and the sealing edge 121 is the lead-out area 122. The electrolyte is filled between the electrode assembly 110 and the packaging bag 120. The area of the lead-out area 122 per unit capacity of the battery cell 100 satisfies the interval of 18mm. 2 / Ah-25mm 2 / Ah.

[0076] In the above technical solution, the area of the lead-out region 122 in the battery cell 100 is designed so that the area of the lead-out region 122 in the battery cell 100 is within a reasonable range, which is beneficial to increasing the amount of electrolyte in the battery cell 100. At the same time, it is beneficial to reduce the risk of reduced energy density of the battery cell 100 due to the lead-out region 122 occupying the space in the packaging bag 120 for arranging the electrode assembly 110, so that the energy density of the battery cell 100 can meet the usage requirements while increasing the service life of the battery cell 100.

[0077] Please refer to Figure 3In some examples, the electrode assembly 110 is provided with a positive electrode tab and a negative electrode tab at one end in the first direction, and the packaging bag 120 wraps the electrode assembly 110. The packaging bag 120 is fitted with the electrode assembly 110 at one end in the first direction away from the electrode assembly 110 where the positive electrode tab and the negative electrode tab are provided, so as to reduce the risk of shaking of the electrode assembly 110 and improve the reliability of the electrode assembly 110.

[0078] The packaging bag 120 is provided with a sealing edge 121 at one end thereof near the electrode assembly 110 in the first direction where the positive electrode tab and the negative electrode tab are provided. A portion of the positive electrode lead-out tab 111 extends out of the packaging bag 120 from the sealing edge 121, and another portion of the positive electrode lead-out tab 111 is arranged in the packaging bag 120 and electrically connected to the positive electrode tab. A portion of the negative electrode lead-out tab 112 extends out of the packaging bag 120 from the sealing edge 121, and another portion of the negative electrode lead-out tab 112 is arranged in the packaging bag 120 and electrically connected to the negative electrode tab.

[0079] The space between the end of the electrode assembly 110 facing the lead-out tab (including the positive lead-out tab 111 and the negative lead-out tab 112) and the edge seal 121 is defined as the lead-out area 122. The minimum dimension of the lead-out area 122 in the first direction is H. That is, the distance between the end of the electrode assembly 110 facing the lead-out tab and the edge seal 121 in the first direction is H, and the width of the packaging bag 120 in the second direction is W. H*W is the area of the lead-out area 122. The area of the lead-out area 122 per unit capacity of the battery cell 100 is H*W / Cn, where Cn is the nominal capacity of the battery cell 100.

[0080] It should be noted that the “first direction” can be understood as the length direction of the electrode assembly 110, the “second direction” can be understood as the width direction of the electrode assembly 110, and the “third direction” can be understood as the thickness direction of the electrode assembly 110. For specific directions, please refer to Figure 3 and Figure 4 As shown, Figure 4 A schematic structural diagram of the electrode assembly 110 provided in some embodiments of the present application.

[0081] Please refer to Figure 4 In other examples, the electrode assembly 110 is provided with a positive electrode tab at one end in the first direction, and the packaging bag 120 is provided with a sealing edge 121 at one end in the first direction close to the electrode assembly 110 where the positive electrode tab is provided. The positive lead-out tab 111 and the positive electrode tab are located on the same side of the electrode assembly 110, and a portion of the positive lead-out tab 111 extends out of the packaging bag from the sealing edge 121. Another portion of the positive lead-out tab 111 is located in the packaging bag 120 and is electrically connected to the positive electrode tab. The space between the end of the electrode assembly 110 facing the positive electrode lead-out tab 111 and the side sealing edge 121 is part of the lead-out area 122.

[0082] A negative electrode ear is provided at the other end of the electrode assembly 110 in the first direction, and a sealing edge 121 is provided at the end of the packaging bag 120 in the first direction close to the electrode assembly 110 where the negative electrode ear is provided. The negative lead-out sheet 112 and the negative electrode ear are located on the same side of the electrode assembly 110, and a portion of the negative lead-out sheet 112 extends out of the packaging bag from the side sealing edge 121, and the other portion of the negative lead-out sheet 112 is located in the packaging bag 120 and is electrically connected to the negative electrode ear. The space between the end of the electrode assembly 110 facing the negative electrode lead-out sheet 112 and this side sealing edge 121 is the other portion of the lead-out area 122.

[0083] The sum of the dimensions of the two parts of the above-mentioned lead-out area 122 in the first direction is the minimum dimension H of the lead-out area 122 in the first direction, the width of the packaging bag 120 in the second direction is W, H*W is the area of the lead-out area 122, and the area of the lead-out area 122 per unit capacity of the battery cell 100 is H*W / Cn, where Cn is the nominal capacity of the battery cell 100.

[0084] Considering that the area of the lead-out region 122 not only affects the amount of electrolyte in the battery cell 100, but also affects the electrode assembly 110 in the battery cell 100, the area of the lead-out region 122 is designed so that the battery cell 100 meets the following requirements: 18mm 2 / Ah≤(H*W) / Cn≤25mm 2 / Ah, so that the area of the lead-out region 122 per unit capacity of the battery cell 100 is within a reasonable range, which is conducive to rationalizing the volume of the lead-out region 122. That is to say, if the area of the lead-out region 122 per unit capacity of the battery cell 100 is large, then the volume of the lead-out region 122 per unit capacity of the battery cell 100 is large; if the area of the lead-out region per unit capacity of the battery cell 100 is small, then the volume of the lead-out region 122 per unit capacity of the battery cell 100 is small, thereby affecting the amount of electrolyte filled in the packaging bag 120 and the space in the packaging bag 120 that can be used to arrange the electrode assembly 110. This is conducive to making the amount of electrolyte filled in the battery cell 100 within a reasonable range, improving the performance of the electrode assembly 110, and extending the service life of the electrode assembly 110, thereby helping to improve the service life of the battery cell 100, and helping to reduce the risk of the lead-out region 122 encroaching on the space in the battery cell 100 for arranging the electrode assembly 110, thereby helping to ensure that the energy density of the battery cell 100 can meet the usage requirements.

[0085] In some specific examples of the present application, the battery cell 100 is a soft-pack battery, and the packaging bag 120 can be constructed as an aluminum-plastic film to improve the waterproof and oxygen-proof effect of the packaging bag 120, thereby helping to improve the performance and service life of the battery cell 100; it can be understood that the packaging bag 120 is constructed as an aluminum-plastic film is only an example of the present application and cannot be understood as a limitation of the present application. The specific material of the packaging bag 120 can be determined according to actual production requirements and is not specifically limited here.

[0086] In some embodiments of the present application, the electrolyte injection coefficient satisfies: 2.7g / Ah-3.5g / Ah.

[0087] In the above technical solution, by designing the electrolyte injection coefficient, it is beneficial to improve the service life of the battery cell 100 and at the same time it is beneficial to make the energy density of the battery cell 100 meet the use requirements.

[0088] Specifically, by ensuring that the electrolyte injection coefficient meets 2.7g / Ah-3.5g / Ah, it is beneficial to reduce the risk of insufficient electrolyte in the battery cell 100, thereby improving the wetting effect of the electrode, reducing the risk of lithium deposition in local areas of the electrode, thereby accelerating the aging and damage of the electrode assembly 110, and further improving the service life of the electrode assembly 110. At the same time, it is beneficial to allow the electrode assembly 110 in the battery cell 100 to fully participate in the reaction, increase the total energy that the battery cell 100 can release, and thus help improve the energy density of the battery cell 100.

[0089] In addition, it is helpful to reduce the risk of excessive electrolyte in the battery cell 100, thereby helping to reduce the risk of damage to the battery cell 100, and helping to prevent the electrode assembly 110 (specifically, the active material of the electrode assembly 110) in the packaging bag 120 from decreasing due to the increase in the mass proportion of the electrolyte in the packaging bag 120, thereby improving the energy density of the battery cell 100.

[0090] Please refer to Figure 3 In some embodiments of the present application, in the first direction, the minimum dimension of the lead-out area 122 is H, the length of the packaging bag 120 is L, and the ratio of the minimum dimension H of the lead-out area 122 to the length L of the packaging bag is in the range of 3.6% to 5.6%, and the first direction is the direction of the protruding tab of the electrode assembly 110; wherein, the first direction is the direction of the protruding tab of the electrode assembly 110.

[0091] In the above technical solution, the length of the packaging bag 120 and the minimum size of the lead-out area 122 in the first direction are designed in a correlated manner to reserve sufficient space for the electrolyte in the packaging bag 120, thereby improving the cycle performance and service life of the electrode assembly 110, and at the same time reducing the risk of the lead-out area 122 excessively occupying the space used to arrange the electrode assembly 110, thereby reducing the risk of a decrease in the energy density of the electrode assembly 110.

[0092] For example, taking the length L of the packaging bag 120 as 600 mm as an example, the minimum dimension H of the lead-out area 122 in the first direction can be in the range of 21.6 mm to 33.6 mm, so as to reasonably allocate the space in the packaging bag 120, so that there is sufficient space in the packaging bag 120 for arranging the lead-out area 122, ensuring sufficient wetting of the electrode sheet and playing a sufficient role in lithium ion transmission, which is beneficial to improving the service life of the electrode assembly 110, and at the same time is beneficial to allowing the electrode assembly 110 to fully participate in the reaction and improve the energy density of the battery cell 100. In addition, it is beneficial to reduce the risk of the lead-out area 122 excessively occupying the space used to arrange the electrode assembly 110, thereby helping to reduce the risk of reduced energy density of the battery cell 100, and can reduce the risk of increased internal pressure of the battery cell 100 due to excessive amount of electrolyte in the battery cell 100, thereby helping to improve the service life of the battery cell 100.

[0093] Please refer to Figure 3 The ratio of the minimum dimension H of the lead-out area 122 to the length L of the packaging bag 120 ranges from 4.4 percent to 5.2 percent.

[0094] In the above technical solution, by further correlating the length of the packaging bag 120 with the minimum size of the lead-out area 122 in the first direction, sufficient space is reserved for the electrolyte in the packaging bag 120, thereby further improving the cycle performance and service life of the electrode assembly 110. At the same time, it is beneficial to further reduce the risk of the lead-out area 122 excessively occupying the space used to arrange the electrode assembly 110, thereby reducing the risk of a decrease in the energy density of the electrode assembly 110.

[0095] For example, taking the length L of the packaging bag 120 as 600 mm as an example, the minimum dimension H of the lead-out area 122 in the first direction can range from 26.4 mm to 31.2 mm, so as to further improve the rationality of the space allocation in the packaging bag 120, so that there is sufficient space in the packaging bag 120 for arranging the lead-out area 122, which is beneficial to increase the amount of electrolyte in the battery cell 100, ensure sufficient infiltration of the electrode sheet, and play a sufficient lithium ion transmission role, thereby helping to reduce the risk of lithium deposition in the local area of the electrode sheet, thereby accelerating the aging and damage of the electrode assembly 110, and further helping to improve the service life of the electrode assembly 110. At the same time, it is beneficial to enable the electrode assembly 110 to fully participate in the reaction, thereby increasing the total energy that the battery cell 100 can release, that is, improving the energy density of the battery cell 100.

[0096] In addition, it is helpful to reduce the risk of reduced energy density of the battery cell 100 due to the lead-out area 122 occupying the space for arranging the electrode assembly 110 in the packaging bag 120, and it is helpful to prevent the internal pressure of the battery cell 100 from increasing due to the presence of a large amount of electrolyte in the battery cell 100, thereby helping to reduce the risk of damage to the battery cell 100 and extend the service life of the battery cell 100.

[0097] Please refer to Figure 4 In some embodiments of the present application, in the first direction, one end of the electrode assembly 110 is provided with a positive electrode ear and the other end is provided with a negative electrode ear, and the lead-out area 122 includes a first lead-out area 1221 and a second lead-out area 1222 located at both ends of the electrode assembly 110, the minimum dimension of the first lead-out area 1221 in the first direction is H1, the minimum dimension of the second lead-out area 1222 in the first direction is H2, the total dimension of the lead-out area 122 in the first direction is H, and the minimum dimension H of the lead-out area 122 is the sum of the minimum dimension H1 of the first lead-out area 1221 in the first direction and the minimum dimension H2 of the second lead-out area 1222 in the first direction.

[0098] In the above technical solution, positive and negative ears are respectively provided at both ends of the electrode assembly 110 in the first direction to increase the distance between the positive and negative ears and reduce the risk of short circuit of the electrode assembly 110. Based on the structure of providing positive and negative ears at both ends of the electrode assembly 110, a first lead-out area 1221 and a second lead-out area 1222 are provided at both ends of the electrode assembly 110, so that the positive lead-out tab 111 and the negative lead-out tab 112 can be extended from the packaging bag 120. This is beneficial for the electrolyte to evenly infiltrate the electrode assembly 110, thereby improving the performance of the electrode assembly 110.

[0099] Illustratively, a positive electrode tab is provided at one end of the electrode assembly 110 in the first direction, and a negative electrode tab is provided at the other end of the electrode assembly 110 in the first direction, so as to increase the distance between the positive electrode tab and the negative electrode tab and reduce the risk of short circuit of the electrode assembly 110.

[0100] Furthermore, the packaging bag 120 is provided with a sealing edge 121 at one end of the electrode assembly 110 in the first direction, where the positive electrode tab is provided. The positive lead-out tab 111 and the positive electrode tab are located on the same side of the electrode assembly 110. A portion of the positive lead-out tab 111 extends out of the packaging bag from the sealing edge 121, and another portion of the positive lead-out tab 111 is located in the packaging bag 120 and is electrically connected to the positive electrode tab. The space between the end of the electrode assembly 110 facing the positive electrode lead-out tab 111 and the side sealing edge 121 is the first lead-out area 1221.

[0101] A negative electrode ear is provided at the other end of the electrode assembly 110 in the first direction, and a sealing edge 121 is provided at the end of the packaging bag 120 in the first direction close to the electrode assembly 110 where the negative electrode ear is provided. The negative lead-out sheet 112 and the negative electrode ear are located on the same side of the electrode assembly 110, and a portion of the negative lead-out sheet 112 extends out of the packaging bag from the side sealing edge 121, and the other portion of the negative lead-out sheet 112 is located in the packaging bag 120 and is electrically connected to the negative electrode ear. The space between the end of the electrode assembly 110 facing the negative electrode lead-out sheet 112 and this side sealing edge 121 is a second lead-out area 1222.

[0102] The first lead-out area 1221 and the second lead-out area 1222 are both filled with electrolyte, that is, both ends of the electrode assembly 110 in the first direction can be wetted by the electrolyte to facilitate the penetration of the electrolyte, and is beneficial to improving the uniformity of the electrolyte infiltration of the electrode assembly 110, which is beneficial to making the electrode assembly 110 fully contact with the electrolyte, thereby improving the performance of the electrode assembly 110.

[0103] Please refer to Figure 4 In some embodiments of the present application, in the first direction, the length of the packaging bag 120 is L, and the ratio of the minimum dimension H1 of the first lead-out area 1221 in the first direction to the length L of the packaging bag 120 is in a range of 1.8 percent to 2.8 percent; and / or in the first direction, the length of the packaging bag 120 is L, and the ratio of the minimum dimension H2 of the second lead-out area 1222 in the first direction to the length L of the packaging bag 120 is in a range of 1.8 percent to 2.8 percent.

[0104] In the above technical solution, by designing the minimum dimension of the first lead-out area 1221 in the first direction and the length dimension of the packaging bag 120 in a correlated manner, the space occupied by the first lead-out area 1221 in the packaging bag 120 is reasonably allocated, which is beneficial to improving the wetting effect of the electrolyte on the end of the electrode assembly 110 provided with the positive electrode ear, and at the same time is beneficial to reducing the risk of insufficient space for arranging other components in the packaging bag 120 due to the excessive size of the first lead-out area 1221; by designing the minimum dimension of the second lead-out area 1222 in the first direction and the length dimension of the packaging bag 120 in a correlated manner, the space occupied by the second lead-out area 1222 in the packaging bag 120 is reasonably allocated, which is beneficial to improving the wetting effect of the electrolyte on the end of the electrode assembly 110 provided with the negative electrode ear, and at the same time is beneficial to reducing the risk of insufficient space for arranging other components in the packaging bag 120 due to the excessive size of the second lead-out area 1222.

[0105] In some examples, the battery cell 100 satisfies: the value range of H1 / L is 1.8%-2.8%. Taking the length L of the packaging bag 120 as 600 mm as an example, the value range of the minimum dimension H1 of the first lead-out area 1221 in the first direction can be 10.8 mm-16.8 mm, so as to reasonably distribute the occupied space of the first lead-out area 1221 in the packaging bag 120, so that the area of the first lead-out area 1221 is sufficient, which is beneficial to increase the amount of electrolyte filled into the end of the electrode assembly 110 where the positive electrode ear is provided, improve the wetting effect of the electrolyte on the electrode assembly 110, and further help to improve the performance and service life of the electrode assembly 110. At the same time, it is beneficial to prevent the first lead-out area 1221 from occupying the space for arranging the electrode assembly 110 in the packaging bag 120 due to its excessive area, and help to prevent the energy density of the battery cell 100 from decreasing.

[0106] In other examples, the battery cell 100 satisfies: the value range of H2 / L is 1.8%-2.8%. Taking the length L of the packaging bag 120 as 600 mm as an example, the value range of the minimum dimension H2 of the second lead-out area 1222 in the first direction can be 10.8 mm-16.8 mm, so as to reasonably distribute the occupied space of the second lead-out area 1222 in the packaging bag 120, so that the area of the second lead-out area 1222 is sufficient, which is beneficial to increase the amount of electrolyte filled into the end of the electrode assembly 110 where the negative electrode ear is provided, thereby facilitating the wetting effect of the electrolyte on the electrode assembly 110, and further facilitating the performance and service life of the electrode assembly 110, and at the same time preventing the second lead-out area 1222 from occupying the space for arranging the electrode assembly 110 in the packaging bag 120 due to being too large, and preventing the energy density of the battery cell 100 from being reduced.

[0107] In some other examples, the battery cell 100 satisfies the following conditions simultaneously: the value range of H1 / L is 1.8%-2.8% and the value range of H2 / L is 1.8%-2.8%. Taking the length L of the packaging bag 120 as 600 mm as an example, the value range of the minimum dimension H1 of the first lead-out area 1221 in the first direction can be 10.8 mm-16.8 mm. Similarly, the value range of the minimum dimension H2 of the second lead-out area 1222 in the first direction can be 10.8 mm-16.8 mm, so as to reasonably allocate the first lead-out area 1221 and the second lead-out area 1222 in the packaging bag 120. 0, so that the first lead-out area 1221 and the second lead-out area 1222 have sufficient areas in the packaging bag 120, which is beneficial to increasing the amount of electrolyte filled in the packaging bag 120, and is beneficial to improving the uniformity of the electrolyte infiltrating the electrode assembly 110, and improving the service life of the electrode assembly 110, thereby helping to improve the service life of the battery cell 100, and at the same time helping to prevent the first lead-out area 1221 and the second lead-out area 1222 from occupying too much space, resulting in insufficient space for arranging the electrode assembly 110 in the packaging bag 120, thereby helping to improve the energy density of the battery cell 100.

[0108] Please refer to Figure 4 In some embodiments of the present application, the minimum dimension H1 of the first lead-out area 1221 in the first direction ranges from 10.8 mm to 16.8 mm; and / or the minimum dimension H2 of the second lead-out area 1222 in the first direction ranges from 10.6 mm to 16.8 mm.

[0109] In the above technical solution, by designing the minimum dimension H1 of the first lead-out area 1221 in the first direction, it is helpful to improve the wetting effect of the electrolyte on the end of the electrode assembly 110 provided with the positive electrode ear, and at the same time it is helpful to reduce the risk of insufficient space for arranging the remaining components in the packaging bag 120 due to the excessive size of the first lead-out area 1221; by designing the minimum dimension H2 of the second lead-out area 1222 in the first direction, it is helpful to improve the wetting effect of the electrolyte on the end of the electrode assembly 110 provided with the negative electrode ear, and at the same time it is helpful to reduce the risk of insufficient space for arranging the remaining components in the packaging bag 120 due to the excessive size of the second lead-out area 1222.

[0110] In some examples, the minimum dimension H1 of the first lead-out area 1221 in the first direction ranges from 10.8 mm to 16.8 mm. For example, the minimum dimension H1 of the first lead-out area 1221 in the first direction can be 10.8 mm, 11 mm, 11.2 mm, 12 mm, 13 mm, 13.5 mm, 16.8 mm, etc. It can be understood that the specific value of H1 can be determined according to actual production requirements and is not specifically limited here.

[0111] In other examples, the minimum dimension H2 of the second lead-out area 1222 in the first direction ranges from 10.8 mm to 16.8 mm. For example, the minimum dimension H2 of the second lead-out area 1222 in the first direction can be 10.8 mm, 11 mm, 11.2 mm, 12 mm, 13 mm, 13.5 mm, 16.8 mm, etc. It can be understood that the specific value of H2 can be determined according to actual production requirements and is not specifically limited here.

[0112] In some other examples, the battery cell 100 can simultaneously satisfy the following conditions: 10.8mm≤H1≤16.8mm, 10.8mm≤H2≤16.8mm, so that the area of the first lead-out area 1221 and the second lead-out area 1222 in the packaging bag 120 is sufficient, which is beneficial to increasing the amount of electrolyte filled in the packaging bag 120, and is beneficial to improving the uniformity of the electrolyte infiltration into the electrode assembly 110, and improving the service life of the electrode assembly 110, thereby benefiting to improving the service life of the battery cell 100, and at the same time, it is beneficial to prevent the first lead-out area 1221 and the second lead-out area 1222 from occupying too much space, resulting in insufficient space in the packaging bag 120 for arranging the electrode assembly 110, thereby benefiting to improving the energy density of the battery cell 100.

[0113] Please refer to Figure 4 In some embodiments of the present application, in the first direction, the length of the packaging bag 120 is L, and the ratio of the minimum dimension H1 of the first lead-out area 1221 in the first direction to the length L of the packaging bag 120 is in the range of 2.2 percent to 2.6 percent; and / or in the first direction, the length of the packaging bag 120 is L, and the ratio of the minimum dimension H2 of the second lead-out area 1222 in the first direction to the length L of the packaging bag 120 is in the range of 2.2 percent to 2.6 percent.

[0114] In the above technical solution, by further correlating the size of the first lead-out area 1221 in the first direction and the length of the packaging bag 120, the space occupied by the first lead-out area 1221 in the packaging bag 120 is further reasonably allocated, thereby improving the infiltration effect of the electrolyte on the electrode assembly 110 while preventing the size of the first lead-out area 1221 from being too large and encroaching on the layout space of the electrode assembly 110; by further correlating the size of the second lead-out area 1222 in the first direction and the length of the packaging bag 120, the space occupied by the second lead-out area 1222 in the packaging bag 120 is further reasonably allocated, thereby improving the infiltration effect of the electrolyte on the electrode assembly 110 while preventing the size of the second lead-out area 1222 from being too large and encroaching on the layout space of the electrode assembly 110.

[0115] In some examples, the battery cell 100 satisfies: the value range of H1 / L is 2.2%-2.6%. Taking the length L of the packaging bag 120 as 600 mm as an example, the value range of the minimum dimension H1 of the first lead-out area 1221 in the first direction can be 13.2 mm-15.6 mm, so as to reasonably distribute the occupied space of the first lead-out area 1221 in the packaging bag 120, so that the area of the first lead-out area 1221 is sufficient, which is beneficial to increase the amount of electrolyte filled into the end of the electrode assembly 110 where the positive electrode ear is provided, thereby facilitating the wetting effect of the electrolyte on the electrode assembly 110, and further facilitating the performance and service life of the electrode assembly 110, and at the same time preventing the first lead-out area 1221 from occupying the space for arranging the electrode assembly 110 in the packaging bag 120 due to being too large, and preventing the energy density of the battery cell 100 from being reduced.

[0116] In other examples, the battery cell 100 satisfies: the value range of H2 / L is 2.2%-2.6%. Taking the length L of the packaging bag 120 as 600 mm as an example, the value range of the minimum dimension H2 of the second lead-out area 1222 in the first direction can be 13.2 mm-15.6 mm, so as to reasonably allocate the occupied space of the second lead-out area 1222 in the packaging bag 120, so that the area of the second lead-out area 1222 is sufficient, which is beneficial to increase the amount of electrolyte filled into the end of the electrode assembly 110 where the negative electrode ear is provided, thereby facilitating the wetting effect of the electrolyte on the electrode assembly 110, and further facilitating the performance and service life of the electrode assembly 110, and at the same time preventing the second lead-out area 1222 from occupying the space for arranging the electrode assembly 110 in the packaging bag 120 due to being too large, and preventing the energy density of the battery cell 100 from decreasing.

[0117] In some other examples, the battery cell 100 satisfies the following conditions simultaneously: the value range of H1 / L is 2.2%-2.6% and the value range of H2 / L is 2.2%-2.6%. Taking the length L of the packaging bag 120 as 600 mm as an example, the value range of the minimum dimension H1 of the first lead-out area 1221 in the first direction can be 13.2 mm-15.6 mm. Similarly, the value range of the minimum dimension H1 of the second lead-out area 1222 in the first direction can be 13.2 mm-15.6 mm, so as to reasonably allocate the first lead-out area 1221 and the second lead-out area 1222 in the packaging bag 120. 0, so that the first lead-out area 1221 and the second lead-out area 1222 have sufficient areas in the packaging bag 120, which is beneficial to increasing the amount of electrolyte filled in the packaging bag 120, and is beneficial to improving the uniformity of the electrolyte infiltrating the electrode assembly 110, and improving the service life of the electrode assembly 110, thereby helping to improve the service life of the battery cell 100, and at the same time helping to prevent the first lead-out area 1221 and the second lead-out area 1222 from occupying too much space, resulting in insufficient space for arranging the electrode assembly 110 in the packaging bag 120, thereby helping to improve the energy density of the battery cell 100.

[0118] Please refer to Figure 4 In some embodiments of the present application, the ratio of the minimum dimension H1 of the first lead-out area 1221 in the first direction to the minimum dimension H2 of the second lead-out area 1222 in the first direction ranges from 0.9 to 1.1.

[0119] In the above technical solution, by designing the minimum dimension H1 of the first lead-out area 1221 in the first direction and the minimum dimension H2 of the second lead-out area 1222 in the first direction in a correlation manner, it is beneficial to make the size of the first lead-out area 1221 close to the size of the second lead-out area 1222, which is beneficial to make the amount of electrolyte distributed at both ends of the electrode assembly 110 in the first direction similar, which is beneficial to make the electrolyte uniformly infiltrate the electrode assembly 110, and is beneficial to improve the efficiency of the electrolyte infiltration from the two ends of the electrode assembly 110 to the middle position of the electrode assembly 110.

[0120] For example, taking the minimum dimension H2 of the second lead-out area 1222 in the first direction as 14 mm, the minimum dimension H1 of the first lead-out area 1221 in the first direction can range from 12.6 mm to 15.4 mm. The area of the first lead-out area 1221 is similar to the size of the second lead-out area 1222, so that the amount of electrolyte filled at both ends of the electrode assembly 110 is similar, which is conducive to uniform infiltration of the electrolyte into the electrode assembly 110, and is conducive to improving the efficiency of the electrolyte infiltration from the two ends of the electrode assembly 110 to the middle position of the electrode assembly 110.

[0121] Please refer to Figure 4 In some embodiments of the present application, the ratio of the minimum dimension H1 of the first lead-out area 1221 in the first direction to the minimum dimension H2 of the second lead-out area 1222 in the first direction ranges from 0.95 to 1.05.

[0122] In the above technical solution, by further designing the correlation between the minimum size H1 of the first lead-out area 1221 in the first direction and the minimum size H2 of the second lead-out area 1222 in the first direction, it is beneficial to further make the size of the first lead-out area 1221 close to the size of the second lead-out area 1222, so as to make the amount of electrolyte distributed at both ends of the electrode assembly 110 in the first direction similar, so as to make the electrolyte uniformly infiltrate the electrode assembly 110, and to improve the efficiency of the electrolyte infiltration from the two ends of the electrode assembly 110 to the middle position of the electrode assembly 110.

[0123] For example, taking the minimum dimension H2 of the second lead-out area 1222 in the first direction as 14 mm, the minimum dimension H1 of the first lead-out area 1221 in the first direction can range from 13.3 mm to 14.7 mm. The area of the first lead-out area 1221 is similar to the size of the second lead-out area 1222, so that the amount of electrolyte filled at both ends of the electrode assembly 110 is similar, which is conducive to uniform infiltration of the electrolyte into the electrode assembly 110, and is conducive to improving the efficiency of the electrolyte infiltration from the two ends of the electrode assembly 110 to the middle position of the electrode assembly 110.

[0124] In some embodiments of the present application, the electrode assembly 110 is a laminated electrode assembly and includes a positive electrode sheet and a negative electrode sheet. The positive electrode sheet is provided with a positive electrode ear, and the negative electrode sheet is provided with a negative electrode ear. The active material of the positive electrode sheet is lithium iron phosphate, and the porosity of the active material layer of the negative electrode sheet ranges from twenty percent to thirty-five percent.

[0125] In the above technical solution, by designing the porosity of the active material layer of the negative electrode sheet, it is beneficial to improve the electrolyte infiltration effect on the negative electrode sheet and the liquid retention effect of the negative electrode sheet, thereby helping to increase the service life of the electrode assembly 110, and further helping to increase the service life of the battery cell 100. At the same time, it is beneficial to prevent the compaction density of the electrode assembly 110 from being reduced due to the excessive porosity of the negative electrode sheet, thereby helping to increase the loading amount of the active material of the electrode assembly 110, and further helping to increase the energy density of the battery cell 100.

[0126] Specifically, the high porosity of the active material layer of the negative electrode sheet means that there is more space on the negative electrode sheet to accommodate the electrolyte. Under the action of the pores of the active material layer of the negative electrode sheet, the electrolyte can remain stable on the negative electrode sheet and is not easy to leak from the negative electrode sheet, which is beneficial to improving the electrolyte retention effect, and can increase the contact area between the negative electrode sheet and the electrolyte, improve the infiltration effect of the electrolyte on the negative electrode sheet, which is beneficial to make the reaction on the negative electrode sheet proceed uniformly, and further help to improve the service life of the electrode assembly 110. However, when the porosity of the active material layer of the negative electrode sheet is too large, the mass per unit volume of the negative electrode sheet will be small, resulting in a decrease in the compaction density of the electrode assembly 110, and the negative electrode sheet foil has too little loading of active material per unit volume, and the content of active material will affect the capacity of the battery. Therefore, when the content of active material is too little, the amount of electricity that the battery cell 100 can store and release is reduced, resulting in a low energy density of the battery cell 100.

[0127] Therefore, by designing the porosity of the active material layer of the negative electrode sheet, the porosity of the active material layer of the negative electrode sheet is within a reasonable range, so as to improve the electrolyte infiltration effect on the negative electrode sheet and the liquid retention effect of the negative electrode sheet, while preventing the compaction density of the electrode assembly 110 from being reduced due to the excessive porosity of the active material layer of the negative electrode sheet, thereby facilitating an increase in the loading amount of the active material of the electrode assembly 110, and further facilitating an increase in the energy density of the battery cell 100.

[0128] In some embodiments of the present application, the porosity of the active material layer of the negative electrode sheet ranges from 25% to 30%.

[0129] In the above technical solution, by further designing the porosity of the active material layer of the negative electrode sheet, it is beneficial to further improve the electrolyte infiltration effect on the negative electrode sheet and the liquid retention effect of the negative electrode sheet, thereby helping to increase the service life of the electrode assembly 110, and further helping to increase the service life of the battery cell 100. At the same time, it is beneficial to increase the compaction density of the electrode assembly 110, thereby helping to increase the loading amount of the active material of the electrode assembly 110, and further helping to increase the energy density of the battery cell 100.

[0130] Specifically, the porosity of the active material layer of the negative electrode sheet is small, which means that the proportion of pores in the active material layer of the negative electrode sheet is too small. It can also be understood that the pores in the active material layer of the negative electrode sheet are too few, resulting in poor electrolyte retention effect of the pores. At the same time, it will lead to a small surface area of the negative electrode sheet, and the negative electrode sheet cannot fully contact the electrolyte, resulting in poor wetting effect of the electrolyte on the negative electrode sheet, which is not conducive to the occurrence of reactions on the negative electrode sheet, and the electrolyte is poorly distributed uniformly on the negative electrode sheet, which can easily lead to a decrease in the service life of the electrode assembly 110.

[0131] The porosity of the active material layer of the negative electrode sheet is large, which means that the pore ratio of the active material layer of the negative electrode sheet is too large, resulting in a small mass per unit volume of the negative electrode sheet, thereby reducing the compaction density of the electrode assembly 110, and the loading amount of active material per unit volume of the negative electrode sheet is too small. The content of active material will affect the capacity of the battery. Therefore, when the content of active material is too small, the amount of electricity that the battery cell 100 can store and release is reduced, resulting in a low energy density of the battery cell 100.

[0132] Please refer to Figure 5 , Figure 4 A schematic structural diagram of a battery cell 100 is provided for embodiments of the present application. In some embodiments of the present application, a packaging bag 120 has a length L in a first direction, a width W in a second direction, and a thickness T in a third direction. The packaging bag 120 satisfies the following requirements: 550 mm ≤ L ≤ 650 mm, 100 mm ≤ W ≤ 140 mm, and 12 mm ≤ T ≤ 40 mm. The third direction is perpendicular to both the first and second directions.

[0133] In the above technical solution, the size of the packaging bag 120 is designed so that there is enough space in the packaging bag 120 for arranging the lead-out area 122 and the electrode assembly 110, which is beneficial to extending the service life of the battery cell 100 and improving the energy density of the battery cell 100.

[0134] Exemplarily, the length L of the packaging bag 120 can be 550 mm, 560 mm, 580 mm or 650 mm, etc., the width W of the packaging bag 120 can be 100 mm, 110 mm, 115 mm, 120 mm, 130 mm or 140 mm, etc., and the thickness T of the packaging bag 120 can be 12 mm, 17 mm, 18 mm, 18.5 mm, 20 mm, 25 mm, 30 mm, 35 mm or 40 mm, etc.

[0135] It is understandable that the length L, width W and thickness T of the packaging bag 120 can be determined according to actual production requirements and are not specifically limited here, as long as the size of the packaging bag 120 can meet actual production requirements.

[0136] In some embodiments of the present application, the electrolyte comprises dimethyl carbonate (ie, DMC) or ethyl carbonate (ie, EMC).

[0137] In the above technical solution, by designing the composition of the electrolyte, it is beneficial to reduce the viscosity of the electrolyte and improve the wetting effect of the electrolyte on the electrode assembly 110, thereby improving the cycle performance of the electrode assembly 110.

[0138] In some examples, the electrolyte includes DMC, which is a linear carbonate. The molecular structure of linear carbonate is relatively regular and the interaction between its molecules is weak. Therefore, by making the electrolyte include DMC, it is beneficial to reduce the viscosity of the electrolyte, thereby reducing the electrolyte's resistance to ion transmission, and further improving the charge and discharge efficiency of the electrode assembly 110, and further improving the cycle performance of the electrode assembly 110.

[0139] In other examples, the components of the electrolyte include EMC, which is a linear carbonate. The molecular structure of linear carbonate is relatively regular and the interaction force between its molecules is weak. Therefore, by making the components of the electrolyte include DMC, it is beneficial to reduce the viscosity of the electrolyte, thereby reducing the electrolyte's resistance to ion transmission, and further improving the charge and discharge efficiency of the electrode assembly 110, and further improving the cycle performance of the electrode assembly 110.

[0140] In some other examples, the components of the electrolyte include DMC and EMC to reduce the viscosity of the electrolyte, which is beneficial to reducing the electrolyte's resistance to ion transport, thereby helping to improve the charge and discharge efficiency of the electrode assembly 110, and thereby helping to improve the cycle performance of the electrode assembly 110.

[0141] In some embodiments of the present application, the electrolyte comprises dimethyl carbonate and ethyl carbonate, and the sum of the mass percentages of dimethyl carbonate and ethyl carbonate in the electrolyte ranges from 60% to 80%.

[0142] In the above technical solution, by designing the composition ratio of the electrolyte, it is beneficial to reduce the viscosity of the electrolyte and improve the wetting effect of the electrolyte on the electrode assembly 110, thereby improving the cycle performance of the electrode assembly 110.

[0143] Specifically, DMC and EMC are both linear carbonates. The molecular structure of linear carbonates is relatively regular and the interaction force between its molecules is weak. Therefore, by increasing the content of DMC and EMC in the electrolyte, it is beneficial to reduce the viscosity of the electrolyte, thereby reducing the electrolyte's resistance to ion transmission, and further improving the charge and discharge efficiency of the electrode assembly 110, and further improving the cycle performance of the electrode assembly 110.

[0144] However, if the content of DMC and EMC is too high, the dissociation ability of lithium salts in the electrolyte will be reduced, thereby reducing the conductivity of the electrolyte and worsening the performance of the electrode assembly 110. Therefore, by setting the sum of the mass percentages of DMC and EMC in the electrolyte to 60%-80%, so that the viscosity of the electrolyte is within a reasonable range, the cycle performance of the electrode assembly 110 is improved, which is beneficial to prevent the problem of decreased electrolyte conductivity caused by excessive use of DMC and EMC, and to increase the service life of the battery cell 100.

[0145] It is understandable that the specific mass percentages of DMC and EMC in the electrolyte can be determined according to actual production requirements and are not specifically limited here.

[0146] The following briefly describes a method for testing the cycle performance of the battery cell 100 according to an embodiment of the present application.

[0147] Under the condition of 25°C, the battery cell 100 is subjected to a charge-discharge cycle test on a charge-discharge instrument with a cycle rate of 0.5P (i.e., both the charge rate and the discharge rate are 0.5P) and a charging voltage of 2.5V to 3.65V. The capacity retention rate after the cycle is calculated. Under the condition of 25°C, the capacity retention rate after the cycle is:

[0148] Capacity retention rate after the nth cycle=(discharge capacity after the nth cycle / discharge capacity at the first cycle)×100%.

[0149] It should be noted that “P” refers to the rated power of the battery cell 100 .

[0150] The following briefly describes the method for calculating the electrolyte injection coefficient of the embodiment of the present application.

[0151] First, weigh the battery cell 100, and then record the weight of the battery cell 100 as M0; further disassemble the electrode assembly 110, clean, dry and weigh the structural parts of the battery cell 100 (including the packaging bag 120, the electrode assembly 110, the positive electrode lead-out sheet 111, the negative electrode lead-out sheet 112 and the tape, etc.), and record the weight of the structural parts as M1; immerse the disassembled positive electrode sheet, negative electrode sheet and isolation membrane in a sufficient amount of DMC solvent for 5 hours, take out and dry, weigh the weight of the positive electrode sheet, negative electrode sheet and isolation membrane respectively, and record the sum of the weights of the three as M2. The electrolyte filling coefficient = (M0-M1-M2) / nominal capacity of the battery cell 100.

[0152]

[0153] Referring to Table 1, in Example 1 of the present application, the capacity of the battery cell 100 is 160Ah, the length L of the packaging bag 120 of the battery cell 100 is 600mm, the width W is 123mm, the thickness T is 18mm, and the area of the lead-out region 122 per unit capacity is set to 22mm 2The electrolyte filling coefficient is 3.05 g / Ah, the ratio of the minimum dimension H1 of the first lead-out area 1221 in the first direction to the length L of the packaging bag 120 is 2.4%, the ratio of the minimum dimension H2 of the second lead-out area 1222 in the first direction to the length L of the packaging bag 120 is 2.4%, and the ratio of the minimum dimension H1 of the first lead-out area 1221 in the first direction to the minimum dimension H2 of the second lead-out area 1222 in the first direction is 1.

[0154] In Example 2 of the present application, the capacity of the battery cell 100 is 160Ah, the length L of the packaging bag 120 of the battery cell 100 is 600mm, the width W is 123mm, the thickness T is 18mm, and the area of the lead-out region 122 per unit capacity is set to 22mm. 2 The electrolyte filling coefficient is 2.7 g / Ah, the ratio of the minimum dimension H1 of the first lead-out area 1221 in the first direction to the length L of the packaging bag 120 is 2.4%, the ratio of the minimum dimension H2 of the second lead-out area 1222 in the first direction to the length L of the packaging bag 120 is 2.4%, and the ratio of the minimum dimension H1 of the first lead-out area 1221 in the first direction to the minimum dimension H2 of the second lead-out area 1222 in the first direction is 1.

[0155] In Example 3 of the present application, the capacity of the battery cell 100 is 160Ah, the length L of the packaging bag 120 of the battery cell 100 is 600mm, the width W is 123mm, the thickness T is 18mm, and the area of the lead-out region 122 per unit capacity is set to 22mm 2 The electrolyte filling coefficient is 3.5 g / Ah, the ratio of the minimum dimension H1 of the first lead-out area 1221 in the first direction to the length L of the packaging bag 120 is 2.4%, the ratio of the minimum dimension H2 of the second lead-out area 1222 in the first direction to the length L of the packaging bag 120 is 2.4%, and the ratio of the minimum dimension H1 of the first lead-out area 1221 in the first direction to the minimum dimension H2 of the second lead-out area 1222 in the first direction is 1.

[0156] In Example 4 of the present application, the capacity of the battery cell 100 is 160Ah, the length L of the packaging bag 120 of the battery cell 100 is 600mm, the width W is 123mm, the thickness T is 18mm, and the area of the lead-out region 122 per unit capacity is set to 18mm 2The electrolyte filling coefficient is 2.9 g / Ah, the ratio of the minimum dimension H1 of the first lead-out area 1221 in the first direction to the length L of the packaging bag 120 is 1.9%, the ratio of the minimum dimension H2 of the second lead-out area 1222 in the first direction to the length L of the packaging bag 120 is 1.9%, and the ratio of the minimum dimension H1 of the first lead-out area 1221 in the first direction to the minimum dimension H2 of the second lead-out area 1222 in the first direction is 1.

[0157] In Example 5 of the present application, the capacity of the battery cell 100 is 160Ah, the length L of the packaging bag 120 of the battery cell 100 is 600mm, the width W is 123mm, the thickness T is 18mm, and the area of the lead-out region 122 per unit capacity is set to 25mm. 2 The electrolyte filling coefficient is 3.2 g / Ah, the ratio of the minimum dimension H1 of the first lead-out area 1221 in the first direction to the length L of the packaging bag 120 is 2.8%, the ratio of the minimum dimension H2 of the second lead-out area 1222 in the first direction to the length L of the packaging bag 120 is 2.8%, and the ratio of the minimum dimension H1 of the first lead-out area 1221 in the first direction to the minimum dimension H2 of the second lead-out area 1222 in the first direction is 1.

[0158] In Example 6 of the present application, the capacity of the battery cell 100 is 160Ah, the length L of the packaging bag 120 of the battery cell 100 is 600mm, the width W is 123mm, the thickness T is 18mm, and the area of the lead-out region 122 per unit capacity is set to 22mm. 2 The injection coefficient of the electrolyte is 3.05 g / Ah, the ratio of the minimum dimension H1 of the first lead-out area 1221 in the first direction to the length L of the packaging bag 120 is 2.3%, the ratio of the minimum dimension H2 of the second lead-out area 1222 in the first direction to the length L of the packaging bag 120 is 2.5%, and the ratio of the minimum dimension H1 of the first lead-out area 1221 in the first direction to the minimum dimension H2 of the second lead-out area 1222 in the first direction is 0.91.

[0159] In Example 7 of the present application, the capacity of the battery cell 100 is 160Ah, the length L of the packaging bag 120 of the battery cell 100 is 600mm, the width W is 123mm, the thickness T is 18mm, and the area of the lead-out region 122 per unit capacity is set to 22mm 2The electrolyte filling coefficient is 3.05 g / Ah, the ratio of the minimum dimension H1 of the first lead-out area 1221 in the first direction to the length L of the packaging bag 120 is 2.5%, the ratio of the minimum dimension H2 of the second lead-out area 1222 in the first direction to the length L of the packaging bag 120 is 2.3%, and the ratio of the minimum dimension H1 of the first lead-out area 1221 in the first direction to the minimum dimension H2 of the second lead-out area 1222 in the first direction is 1.01.

[0160] In Example 8 of the present application, the capacity of the battery cell 100 is 88Ah, the length L of the packaging bag 120 of the battery cell 100 is 560mm, the width W is 100mm, the thickness T is 13mm, and the area of the lead-out region 122 per unit capacity is set to 24mm 2 The electrolyte filling coefficient is 3.05 g / Ah, the ratio of the minimum dimension H1 of the first lead-out area 1221 in the first direction to the length L of the packaging bag 120 is 1.9%, the ratio of the minimum dimension H2 of the second lead-out area 1222 in the first direction to the length L of the packaging bag 120 is 1.9%, and the ratio of the minimum dimension H1 of the first lead-out area 1221 in the first direction to the minimum dimension H2 of the second lead-out area 1222 in the first direction is 1.

[0161] In Example 9 of the present application, the capacity of the battery cell 100 is 249Ah, the length L of the packaging bag 120 of the battery cell 100 is 640mm, the width W is 135mm, the thickness T is 24mm, and the area of the lead-out region 122 per unit capacity is set to 19mm 2 The electrolyte filling coefficient is 3.05 g / Ah, the ratio of the minimum dimension H1 of the first lead-out area 1221 in the first direction to the length L of the packaging bag 120 is 2.7%, the ratio of the minimum dimension H2 of the second lead-out area 1222 in the first direction to the length L of the packaging bag 120 is 2.7%, and the ratio of the minimum dimension H1 of the first lead-out area 1221 in the first direction to the minimum dimension H2 of the second lead-out area 1222 in the first direction is 1.

[0162] In Comparative Example 1, the capacity of the battery cell is 160Ah, the length L of the battery cell packaging bag is 600mm, the width W is 123mm, the thickness T is 18mm, and the area of the lead-out region 122 per unit capacity is set to 22mm. 2 The electrolyte filling coefficient is 3.05 g / Ah, the ratio of the minimum dimension H1 of the first lead-out area in the first direction to the length L of the packaging bag is 2.0%, the ratio of the minimum dimension H2 of the second lead-out area in the first direction to the length L of the packaging bag is 2.8%, and the ratio of the minimum dimension H1 of the first lead-out area in the first direction to the minimum dimension H2 of the second lead-out area in the first direction is 0.71.

[0163] In Comparative Example 2, the capacity of the battery cell is 160Ah, the length L of the battery cell packaging bag is 600mm, the width W is 123mm, the thickness T is 18mm, and the area of the lead-out region 122 per unit capacity is set to 22mm. 2 The electrolyte filling coefficient is 2.3 g / Ah, the ratio of the minimum dimension H1 of the first lead-out area in the first direction to the length L of the packaging bag is 2.4%, the ratio of the minimum dimension H2 of the second lead-out area in the first direction to the length L of the packaging bag is 2.4%, and the ratio of the minimum dimension H1 of the first lead-out area in the first direction to the minimum dimension H2 of the second lead-out area in the first direction is 1.

[0164] In Comparative Example 3, the capacity of the battery cell is 160Ah, the length L of the battery cell packaging bag is 600mm, the width W is 123mm, the thickness T is 18mm, and the area of the lead-out region 122 per unit capacity is set to 14mm 2 The electrolyte injection coefficient is 2.6 g / Ah, the ratio of the minimum dimension H1 of the first lead-out area in the first direction to the length L of the packaging bag is 1.5%, the ratio of the minimum dimension H2 of the second lead-out area in the first direction to the length L of the packaging bag is 1.5%, and the ratio of the minimum dimension H1 of the first lead-out area in the first direction to the minimum dimension H2 of the second lead-out area in the first direction is 1.

[0165] Under the test conditions of 25°C and 2000 cycles, the capacity retention rate of Example 1 of the present application is 91.50%, and the energy density is 186GWh / kg; the capacity retention rate of Example 2 of the present application is 89.50%, and the energy density is 189GWh / kg; the capacity retention rate of Example 3 of the present application is 91.90%, and the energy density is 181GWh / kg; the capacity retention rate of Example 4 of the present application is 90.20%, and the energy density is 187GWh / kg; the capacity retention rate of Example 5 of the present application is 91.80%, and the energy density is 184GWh / kg; the capacity retention rate of Example 6 of the present application is 91. 30%, and the energy density is 186GWh / kg; the capacity retention rate of Example 7 of the present application is 91.30%, and the energy density is 186GWh / kg; the capacity retention rate of Example 8 of the present application is 91.50%, and the energy density is 186GWh / kg; the capacity retention rate of Example 9 of the present application is 90.80%, and the energy density is 186GWh / kg; the capacity retention rate of Comparative Example 1 is 80.20%, and the energy density is 186GWh / kg; the capacity retention rate of Comparative Example 2 is 70.10%, and the energy density is 1946GWh / kg; the capacity retention rate of Comparative Example 3 is 80.20%, and the energy density is 186GWh / kg.

[0166] Comparing Example 1, Example 4, Example 5 and Comparative Example 3, the area of the lead-out region 122 per unit capacity in Example 1 is 22 mm 2 / Ah, and its capacity retention rate is 91.50%. The area of the lead-out region 122 per unit capacity of Example 4 is 18mm 2 / Ah, and its capacity retention rate is 90.20%. The area of the lead-out region 122 per unit capacity of Example 5 is 25mm 2 / Ah, and its capacity retention rate is 91.80%. The area of the lead-out region per unit capacity of Comparative Example 3 is 14mm 2 / Ah, its capacity retention rate is 73.60%. It can be seen that as the area of the lead-out region decreases, the capacity retention rate of the battery cell decreases, and when the area of the lead-out region per unit capacity is less than 18mm 2 / Ah, the capacity retention rate of the battery cell is greatly reduced.

[0167] Comparing Example 2, Example 3 and Comparative Example 2, the electrolyte injection coefficient of Example 2 is 2.7 g / Ah, and its capacity retention rate is 89.50%. The electrolyte injection coefficient of Example 3 is 3.5 g / Ah, and its capacity retention rate is 91.90%. The electrolyte injection coefficient of Comparative Example 2 is 2.3 g / Ah, and its capacity retention rate is 70.10%. That is to say, when other conditions (for example, the capacity of the battery cell, the length of the packaging bag, the width of the packaging bag, the thickness of the packaging bag, and the area of the lead-out area per unit capacity, etc.) are the same, the electrolyte injection coefficient is large and the capacity retention rate of the battery cell is high. When the electrolyte injection coefficient is less than 2.7 g / Ah, the capacity retention rate of the battery cell is greatly reduced.

[0168] Comparing Example 1, Example 6, and Comparative Example 1, in Example 1, the ratio of the minimum dimension H1 of the first lead-out area 1221 in the first direction to the length L of the packaging bag 120 is 2.4%, and the ratio of the minimum dimension H2 of the second lead-out area 1222 in the first direction to the length L of the packaging bag 120 is 2.4%. The ratio of the minimum dimension H1 of the first lead-out area 1221 in the first direction to the minimum dimension H2 of the second lead-out area 1222 in the first direction is 1, and the capacity retention rate is 91.50%. In Example 6, the ratio of the minimum dimension H1 of the first lead-out area 1221 in the first direction to the length L of the packaging bag 120 is 2. 3%, the ratio of the minimum dimension H2 of the second lead-out area 1222 in the first direction to the length L of the packaging bag 120 is 2.5%, the ratio of the minimum dimension H1 of the first lead-out area 1221 in the first direction to the minimum dimension H2 of the second lead-out area 1222 in the first direction is 0.91, and its capacity retention rate is 91.30%; in Example 7, the ratio of the minimum dimension H1 of the first lead-out area 1221 in the first direction to the length L of the packaging bag 120 is 2.5%, the ratio of the minimum dimension H2 of the second lead-out area 1222 in the first direction to the length L of the packaging bag 120 is 2.3%, and the ratio of the minimum dimension H1 of the first lead-out area 1221 in the first direction to the length L of the packaging bag 120 is 0.91. The ratio of the minimum dimension H1 to the minimum dimension H2 of the second lead-out area 1222 in the first direction is 1.01, and its capacity retention rate is 91.30%. In comparative example 1, the ratio of the minimum dimension H1 of the first lead-out area in the first direction to the length L of the packaging bag is 2.0%, the ratio of the minimum dimension H2 of the second lead-out area in the first direction to the length L of the packaging bag is 2.8%, and the ratio of the minimum dimension H1 of the first lead-out area in the first direction to the minimum dimension H2 of the second lead-out area in the first direction is 0.71, and its capacity retention rate is 80.20%. In other words, under the other conditions (for example, the capacity of the battery cell, the length of the packaging bag, the packaging bag), the capacity retention rate is 80.20%. When the width of the first lead-out area, the thickness of the packaging bag, and the area of the lead-out area 122 per unit capacity (etc.) are the same, the capacity retention rate of the battery cell is affected by the ratio of the minimum dimension H1 of the first lead-out area in the first direction to the minimum dimension H2 of the second lead-out area in the first direction, the ratio of the minimum dimension H2 of the second lead-out area in the first direction to the length L of the packaging bag, and the ratio of the minimum dimension H1 of the first lead-out area in the first direction to the minimum dimension H2 of the second lead-out area in the first direction, and when H1 / L, H2 / L or H1 / H2 is not within the range designed in this application (refer to Comparative Example 1), the capacity retention rate of the battery cell is greatly reduced.

[0169] Comparing Example 8 with Comparative Example 1, the electrolyte filling coefficient of Example 8 is the same as that of Comparative Example 1. The capacity and the size of the packaging bag 120 of Example 8 are smaller than those of Comparative Example 1. However, the values of H1 / L, H2 / L, or H1 / H2 of Example 8 are all within the ranges of H1 / L, H2 / L, and H1 / H2 designed in this application, while the value of H1 / H2 of Comparative Example 1 is not within the range designed in this application. In addition, the area of the lead-out region 122 per unit capacity of Example 8 is larger than that of the lead-out region per unit capacity of Comparative Example 1. It can be seen that even if the capacity of the battery cell 100 and the size of the packaging bag 120 are small, the capacity retention rate of the battery cell 100 can be effectively improved by ensuring that the value of H1 / H2 meets the range of H1 / H2 designed in this application and increasing the area of the lead-out region 122.

[0170] Comparing Example 9 with Comparative Example 1, the electrolyte filling coefficient of Example 9 is the same as that of Comparative Example 1. The capacity and the size of the packaging bag 120 of Example 9 are larger than those of Comparative Example 1. However, the values of H1 / L, H2 / L, or H1 / H2 of Example 9 are all within the ranges of H1 / L, H2 / L, and H1 / H2 designed in this application, while the value of H1 / H2 of Comparative Example 1 is not within the range designed in this application. In addition, the area of the lead-out region 122 per unit capacity of Example 9 is smaller than that of the lead-out region per unit capacity of Comparative Example 1. It can be seen that even if the capacity of the battery cell 100, the size of the packaging bag 120, and the area of the lead-out region 122 per unit capacity are large, by ensuring that the value of H1 / H2 meets the range of H1 / H2 designed in this application, the capacity retention rate of the battery cell 100 can be effectively improved.

[0171] To sum up, and with reference to the above table, it can be seen that the capacity retention rate of the battery cell 100 of the embodiment of the present application is higher than the capacity retention rate of the battery cell of the comparative example, and the energy density of the battery cell 100 of the embodiment of the present application is similar to the energy density of the battery cell of the comparative example, that is, the battery cell 100 of the embodiment of the present application has a higher energy density, and at the same time, the capacity retention rate of the battery cell 100 of the embodiment of the present application is higher, so as to effectively improve the service life of the battery cell 100.

[0172] According to some embodiments of the present application, the present application further provides a battery device 200 , which includes the above-mentioned battery cell 100 .

[0173] In the above technical solution, since the battery device 200 is provided with the above-mentioned battery cell 100 and the battery cell 100 has a long service life and a high energy density, it is beneficial to improve the service life and energy density of the battery device 200.

[0174] According to some embodiments of the present application, the present application further provides an energy storage device 1000 , which includes the battery cell 100 of the above embodiment or the battery device 200 of the above embodiment, and the battery cell 100 or the battery device 200 is used to store or provide electrical energy.

[0175] In the above technical solution, since the energy storage device 1000 is provided with the above battery device 200 and the battery device 200 has a high service life and energy density, it is beneficial to improve the service life of the energy storage device 1000 and to meet the power demand of the energy storage device 1000.

[0176] It should be noted that, unless there is any conflict, the embodiments and features in the embodiments of this application can be combined with each other.

[0177] The above are merely preferred embodiments of the present application and are not intended to limit the present application. Those skilled in the art will readily appreciate that various modifications and variations are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present application shall be included within the scope of protection of the present application.

Claims

1. A battery cell, characterized in that: include: An electrode assembly, wherein the electrode assembly is provided with a positive electrode tab and a negative electrode tab; A positive electrode lead-out sheet and a negative electrode lead-out sheet, wherein the positive electrode lead-out sheet is electrically connected to the positive electrode tab, and the negative electrode lead-out sheet is electrically connected to the negative electrode tab; a packaging bag, wherein the packaging bag wraps the electrode assembly, wherein at least one end of the packaging bag is provided with a sealed edge, the positive electrode lead tab and the negative electrode lead tab respectively extend out of the packaging bag from the sealed edge, and the space between a side of the electrode assembly from which the electrode tab extends and the sealed edge serves as a lead-out area; an electrolyte, part of which is filled between the electrode assembly and the packaging bag; The area of the lead-out area of the battery unit capacity meets the interval of 18mm 2 / Ah-28mm 2 / Ah.

2. The battery cell according to claim 1, wherein: The electrolyte injection coefficient meets the following requirements: 2.7g / Ah-3.5g / Ah.

3. The battery cell according to claim 1, wherein: In the first direction, the minimum dimension of the lead-out area is H, the length of the packaging bag is L, and the ratio of the minimum dimension H of the lead-out area to the length L of the packaging bag ranges from 3.6 percent to 5.6 percent. The first direction is the direction in which the electrode assembly extends out of the electrode tab.

4. The battery cell according to claim 3, characterized in that The ratio of the minimum dimension H of the lead-out area to the length L of the packaging bag ranges from 4.4 percent to 5.2 percent.

5. The battery cell according to claim 1, characterized in that In a first direction, the positive electrode tab is provided at one end of the electrode assembly and the negative electrode tab is provided at the other end. The lead-out region includes a first lead-out region and a second lead-out region located at both ends of the electrode assembly. The minimum dimension of the first lead-out region in the first direction is H1, the minimum dimension of the second lead-out region in the first direction is H2, and the minimum dimension of the lead-out region in the first direction is H. The minimum dimension H of the lead-out region is the sum of the minimum dimension H1 of the first lead-out region in the first direction and the minimum dimension H2 of the second lead-out region in the first direction. The first direction is the direction in which the electrode assembly extends out of the tab.

6. The battery cell according to claim 5, characterized in that In the first direction, the length of the packaging bag is L, and the ratio of the minimum dimension H1 of the first lead-out area in the first direction to the length L of the packaging bag is in a range of 1.8% to 2.8%; and / or In the first direction, the length of the packaging bag is L, and the ratio of the minimum dimension H2 of the second lead-out area in the first direction to the length L of the packaging bag is in a range of 1.8% to 2.8%.

7. The battery cell according to claim 6, characterized in that The minimum dimension H1 of the first lead-out area in the first direction ranges from 10.8 mm to 16.8 mm; and / or, A minimum dimension H2 of the second lead-out area in the first direction ranges from 10.6 mm to 16.8 mm.

8. The battery cell according to claim 6, characterized in that In the first direction, the length of the packaging bag is L, and the ratio of the minimum dimension H1 of the first lead-out area in the first direction to the length L of the packaging bag is in a range of 2.2% to 2.6%; and / or In the first direction, the length of the packaging bag is L, and the ratio of the minimum dimension H2 of the second lead-out area in the first direction to the length L of the packaging bag ranges from 2.2 percent to 2.6 percent.

9. The battery cell according to claim 5, characterized in that: A ratio of a minimum dimension H1 of the first lead-out area in the first direction to a minimum dimension H2 of the second lead-out area in the first direction ranges from 0.9 to 1.

1.

10. The battery cell according to claim 9, characterized in that: A ratio of a minimum dimension H1 of the first lead-out area in the first direction to a minimum dimension H2 of the second lead-out area in the first direction ranges from 0.95 to 1.

05.

11. The battery cell according to any one of claims 1 to 10, characterized in that: The electrode assembly is a laminated electrode assembly and includes a positive electrode sheet and a negative electrode sheet. The positive electrode sheet is provided with the positive electrode ear, and the negative electrode sheet is provided with the negative electrode ear. The active material of the positive electrode sheet is lithium iron phosphate, and the porosity of the active material layer of the negative electrode sheet ranges from 20% to 35%.

12. The battery cell according to claim 11, characterized in that The porosity of the active material layer of the negative electrode sheet ranges from 20 percent to 35 percent.

13. The battery cell according to claim 1, characterized in that The electrolyte comprises dimethyl carbonate or ethyl carbonate.

14. The battery cell according to claim 1, characterized in that The length of the packaging bag in the first direction is L, the width in the second direction is W, and the thickness in the third direction is T. The packaging bag meets the range of: 550mm≤L≤650mm, 100mm≤W≤140mm, 12mm≤T≤40mm; wherein the third direction is arranged perpendicular to the first direction and the second direction respectively.

15. A battery device, characterized in that: The invention comprises a plurality of battery cells according to any one of claims 1 to 14.

16. An energy storage device, characterized in that: The battery cell according to any one of claims 1 to 14 or the battery device according to claim 15 is used to store or provide electrical energy.

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