Battery cell, battery device and power-consuming device

Abstract

Battery cell comprising an electrode arrangement, wherein the electrode arrangement comprises a first electrode sheet and a second electrode sheet stacked along the thickness direction of the battery cell, one of the first electrode sheet and the second electrode sheet being a positive electrode sheet and the other being a negative electrode sheet, wherein the first electrode sheet and the second electrode sheet each comprise an electrode sheet main body and at least one electrode tab section, wherein an active material layer is arranged in at least one sub-region of the electrode sheet main body, and wherein the at least one electrode tab section is connected to the electrode sheet main body and projects out of the electrode sheet main body along a first direction, wherein the active material layer of the positive electrode sheet comprises a lithium-containing phosphate with an olivine structure and the dimension of the electrode sheet main body along the longitudinal direction of the battery cell is 320 mm to 650 mm, where the first electrode sheet fulfills the following condition: the maximum value of a 2 + b 2 is between 6000 and 110000, where a in the first electrode sheet along the first direction represents the distance between any point A of the electrode sheet main body and the electrode tab section that is closest to point A in at least one electrode tab section, in units of mm; where b in the first electrode sheet represents the distance between point A and the electrode tab section that is closest to point A in at least one electrode tab section along a second direction, in units of mm, one of the first direction and the second direction being parallel to the longitudinal direction and the other being parallel to the lateral direction of the battery cell.

Description

Technical field

[0001] The present application relates to a battery cell, a battery device and a power-consuming device. State of the art

[0002] Battery cells are characterized by high capacity, long lifespan, and other properties, and are therefore widely used in electronic devices such as mobile phones, laptops, e-bikes, electric vehicles, electric aircraft, electric boats, electric toy cars, electric toy ships, electric toy airplanes, and power tools. As battery technology has advanced significantly, the demands on battery performance have also increased. However, the fast-charging capability of battery cells still needs to be improved. Disclosure of the invention

[0003] The present application provides a battery cell, a battery device and a power-consuming device, wherein the fast-charging capability of the battery cell of the present application can be further increased.

[0004] In a first aspect, the embodiments of the present application propose a battery cell, wherein the battery cell comprises an electrode arrangement, the electrode arrangement comprising a first electrode sheet and a second electrode sheet stacked along the thickness direction of the battery cell, one of the first electrode sheet and the second electrode sheet being a positive electrode sheet and the other a negative electrode sheet, the first electrode sheet and the second electrode sheet each comprising an electrode sheet main body and at least one electrode tab section, wherein an active material layer is arranged in at least one sub-region of the electrode sheet main body, and wherein the at least one electrode tab section is connected to the electrode sheet main body and projects out of the electrode sheet main body along a first direction; wherein the active material layer of the positive electrode sheet comprises a lithium-containing phosphate with an olivine structure and the dimension of the electrode sheet main body of the positive electrode sheet along the longitudinal direction of the battery cell is 320 mm to 650 mm; where the first electrode sheet fulfills the following condition: the maximum value of a 2 + b 2 is between 6000 and 110000, where a in the first electrode sheet along the first direction represents the distance between any point A of the electrode sheet main body and the electrode tab section that is closest to point A in at least one electrode tab section, in units of mm; where b in the first electrode sheet represents the distance between point A and the electrode tab section that is closest to point A in at least one electrode tab section along a second direction, in units of mm, one of the first direction and the second direction being parallel to the longitudinal direction and the other being parallel to the lateral direction of the battery cell.

[0005] Therefore, the electrode arrangement in the embodiments of the present application has a stacked structure. The dimensions of the main body of the positive electrode sheet along the longitudinal direction of the battery cell lie within the aforementioned range, resulting in a relatively high energy density of the battery cell. However, this high energy density necessitates a high internal resistance of the electrode sheet. Furthermore, in the present application, the positive electrode active material comprises a lithium-containing phosphate with an olivine structure and low conductivity, which further increases the internal resistance.In order to reduce the internal resistance, the electron transport path in the embodiments of the present application is designed such that the electron transport path within the electrode sheet is relatively short, which reduces the internal resistance of the electrode sheet and thus the internal resistance of the battery cell, which is advantageous for fast charging of the battery cell at high energy density.

[0006] In some embodiments, the first direction runs parallel to the longitudinal direction of the battery cell.

[0007] In some embodiments, the first electrode sheet has several electrode tab sections, with several of the electrode tab sections being arranged on both sides of the electrode sheet main body along the first direction. The electron transport path is shorter, which is advantageous for fast charging of the battery cell.

[0008] In some embodiments, the maximum value of a2 + b 2 25600 to 110000, optionally 25600 to 90000. The electron transport path is shorter, which is advantageous for fast charging of the battery cell.

[0009] In some embodiments, the first direction runs parallel to the width direction of the battery cell. The electron transport path is shorter, which is advantageous for fast charging of the battery cell.

[0010] In some embodiments, at least one electrode tab section of the first electrode sheet is arranged on the same side of the electrode sheet main body along the first direction.

[0011] In some embodiments, the maximum value of a 2 + b 2 6400 to 45000, optionally 6400 to 25000. The electron transport path is shorter, which is advantageous for fast charging of the battery cell.

[0012] In some embodiments, the electrode arrangement has a stacked structure, with the dimensions of the main body of the positive electrode sheet ranging from 80 mm to 150 mm in width. The electron transport path is relatively short, which is advantageous for fast charging of the battery cell.

[0013] In some embodiments, several electrode tab sections are arranged on the same side of the electrode sheet main body in the first electrode sheet. The distance between two adjacent electrode tab sections along the second direction is greater than 0 mm and less than or equal to 300 mm. Each electrode tab accepts a smaller current, and thus the current distribution is more uniform, which is advantageous for fast charging of the battery cell.

[0014] In some embodiments, the second electrode sheet fulfills the following condition: the maximum value of c 2 + d 2is between 6000 and 110000, where c in the second electrode sheet along the first direction represents the distance between any point B of the electrode sheet main body and the electrode tab section that is closest to point B in at least one electrode tab section, in units of mm, where d along the second direction represents the distance between point B and the electrode tab section that is closest to point B in at least one electrode tab section, in units of mm.

[0015] If the second electrode sheet in the embodiments of the present application meets the above-mentioned conditions, the electron transport path is therefore relatively short, which can effectively reduce the internal resistance of the battery cell, and each electrode tab absorbs a smaller current and the current distribution is more uniform, which is advantageous for fast charging of the battery cell.

[0016] In some embodiments, the electrode tab section of the first electrode sheet is arranged on at least one side of the electrode sheet main body along the first direction, and the first electrode sheet satisfies the following condition: n*W1 / W2 is 0.5 to 1.0, where n represents the number of all electrode tab sections on the same side of the electrode sheet main body, W1 represents the average dimension of the electrode tab sections along the second direction, one of the first and second directions being parallel to the longitudinal direction of the battery cell and the other being parallel to the transverse direction of the battery cell, and W2 represents the dimension of the electrode sheet main body along the second direction.The electrode tab section has a higher current-carrying capacity, which has a positive effect on increasing the current-carrying capacity of the battery device and improves the fast-charging performance of the battery device.

[0017] In some embodiments, the battery cell further comprises an electrolyte solution, wherein the electrolyte solution includes a chain-like carboxylic acid ester solvent, the mass fraction of the chain-like carboxylic acid ester solvent in the electrolyte solution being 5% to 30%. The solvent system described above exhibits high conductivity, which can further reduce the internal resistance of the battery cell, thereby reducing heat generation and thus improving the fast-charging performance of the battery cell.

[0018] In some embodiments, the battery cell further comprises an electrolyte solution, wherein the electrolyte solution comprises lithium hexafluorophosphate and lithium bis(fluorosulfonyl)imide, wherein the ratio of the mass fraction of lithium hexafluorophosphate to the mass fraction of lithium bis(fluorosulfonyl)imide, based on the mass of the electrolyte solution, is 0.5 to 4. If the lithium salt meets the above-mentioned conditions, it contributes to improving the lithium-ion conductivity of the electrolyte solution and can improve the fast-charging performance of the battery cell.

[0019] In some embodiments, the conductivity of the electrolyte solution at room temperature is 10 mS / cm to 13 mS / cm. If the conductivity of the electrolyte solution at room temperature, for example 25 °C, is within the aforementioned range, the migration rate of lithium ions in the electrolyte solution is relatively high, which can further reduce the internal resistance of the battery cell, thereby reducing heat generation and improving the fast-charging performance of the battery cell.

[0020] In some embodiments, the lithium-containing phosphate with an olivine structure comprises lithium iron phosphate. The lithium-containing phosphate exhibits excellent cycle stability, which positively impacts cycle performance.

[0021] In some embodiments, the active material layer of the positive electrode sheet is a positive electrode active material layer, and the one-sided coating weight of the positive electrode active material layer is 250 mg / 1540.25 mm². 2 up to 330 mg / 1540.25 mm 2 If the one-sided coating weight of the positive electrode active material layer is within the range mentioned above, the amount of heat generated per unit area of ​​the positive electrode sheet is not too large and the energy density and charging rate performance of the battery cell can also be improved.

[0022] In some embodiments, the compaction density of the positive electrode active material layer is 2.30 g / cm³. 3 up to 2.70 g / cm³ 3, when the battery cell is at a state of charge of 0%. If the compaction density of the positive electrode active material layer is within the aforementioned range, this is advantageous for improving the energy density of the battery cell. Because the positive electrode active material of the positive electrode active material layer is relatively densely packed and the contact resistance between the particles is low, the resistance of the electrode sheet can be further reduced, which can improve the fast-charging performance of the battery cell at high energy density.

[0023] In some embodiments, the main body of the negative electrode sheet comprises a negative electrode current collection section and a negative electrode active material layer arranged on at least one side of the negative electrode current collection section, wherein the negative electrode active material layer comprises a carbon-based material, wherein the negative electrode active material layer comprises a first negative electrode film layer and a second negative electrode film layer, wherein the first negative electrode film layer is arranged on the surface of the negative electrode current collection section and the second negative electrode film layer is connected to a side of the first negative electrode film layer facing away from the negative electrode current collection section.wherein the volume-averaged particle size Dv50 of the carbon-based material of the first negative electrode film layer is greater than or equal to the volume-averaged particle size Dv50 of the carbon-based material of the second negative electrode film layer. In the embodiments of the present application, the particle size of the second negative electrode film layer is relatively small, which shortens the solid-phase transport path of the lithium ions, improves the fast-charging performance, and reduces the problem of lithium plating on the surface of the negative electrode sheet.

[0024] In some embodiments, the carbon-based material of the first negative electrode film layer is in granular form, with a volume-averaged particle size Dv50 of 9.5 µm to 18.5 µm. If the volume-averaged particle size Dv50 of the carbon-based material of the first negative electrode film layer is within the aforementioned range, the solid-phase transport path of the lithium ions can be shortened and the fast-charging performance improved. Furthermore, the material does not agglomerate as readily during the manufacturing process, which can improve the material's stability.

[0025] In some embodiments, the carbon-based material of the second negative electrode film layer is in granular form, with the volume-averaged particle size Dv50 being 7.8 µm to 14.3 µm.If the volume-averaged particle size Dv50 of the carbon-based material of the second negative electrode film layer lies within the aforementioned range, the solid-phase transport path of the lithium ions can be shortened and the fast-charging performance improved. Furthermore, the material does not agglomerate as easily during the manufacturing process, which can improve the material's stability. Additionally, combining the negative electrode active material in the second negative electrode film layer and the negative electrode active material in the first negative electrode film layer within the aforementioned range of volume-averaged particle size is advantageous for creating a gradient pore difference between the second and first negative electrode film layers, reducing the toriosity of lithium ion transport and improving the fast-charging performance of the battery cell.

[0026] In some embodiments, the carbon-based material of the first negative electrode film layer comprises at least one of artificial graphite and natural graphite, and the carbon-based material of the second negative electrode film layer comprises artificial graphite.

[0027] In some embodiments, the active material layer of the negative electrode sheet is a negative electrode active material layer, and the one-sided coating weight of the negative electrode active material layer is 120 mg / 1540.25 mm². 2 up to 180 mg / 1540.25 mm 2If the one-sided coating weight of the negative electrode active material layer is within the range mentioned above, the amount of heat generated per unit area of ​​the negative electrode sheet is not too high and the energy density of the battery cell can also be improved, which has a positive effect on improving the fast charging performance of the battery cell at high energy density.

[0028] In some embodiments, the compaction density of the negative electrode active material layer is 1.30 g / cm³. 3 up to 1.65 g / cm³ 3, when the battery cell is at a state of charge of 0%. If the density of the negative electrode active material layer is within the range mentioned above, this is advantageous for improving the energy density of the battery cell. Because the negative electrode active material of the negative electrode active material layer is relatively densely packed and the contact resistance between the particles is low, the resistance of the electrode sheet can be further reduced, which has a positive effect on improving the fast-charging performance of the battery cell at high energy density.

[0029] In a second aspect, the embodiments of the present application propose a battery device comprising a battery cell according to one of the embodiments of the first aspect of the present application.

[0030] In a third aspect, the embodiments of the present application propose a power-consuming device comprising a battery device according to one of the embodiments of the second or third aspect of the present application. Brief description of the drawings

[0031] To better illustrate the technical solutions in the embodiments of the present application, a brief description of the drawings required in these embodiments is given below. Of course, the drawings described below represent only some embodiments of the present application, and other drawings can be created by a person skilled in the art based on these drawings without any creative effort. Fig. Figure 1 is a schematic representation of the structure of a power-consuming device according to some embodiments of the present application; Fig. Figure 2 is a schematic representation of the structure of a battery pack according to some embodiments of the present application; Fig. Figure 3 is a schematic representation of the structure of a battery module according to some embodiments of the present application; Fig. Figure 4 is a schematic representation of the structure of a battery cell according to some embodiments of the present application; Fig. Figure 5 is a schematic representation of the structure of an electrode arrangement of the battery cell according to some embodiments of the present application; Fig. Figure 6 is a schematic representation of the structure of a first electrode sheet of the battery cell according to some embodiments of the present application; Fig.Figure 7 is a schematic representation of the structure of a first electrode sheet of the battery cell according to some other embodiments of the present application; Fig. Figure 8 is a schematic representation of the structure of a first electrode sheet of the battery cell according to some further embodiments of the present application; Fig. Figure 9 is a schematic representation of the structure of a second electrode sheet of the battery cell according to some embodiments of the present application; Fig. 10 is a schematic representation of the structure of a first electrode sheet of the battery cell according to some further embodiments of the present application; Fig. 11 is a schematic representation of the structure of a first electrode sheet of the battery cell according to some further embodiments of the present application; Fig.Figure 12 is a schematic representation of the structure of a battery cell according to some other embodiments of the present application; Fig. 13 is a schematic representation of the structure of a battery cell according to some further embodiments of the present application; Fig. Figure 14 is a schematic representation of the structure of a battery cell according to some further embodiments of the present application; Fig. Figure 15 is a schematic representation of the structure of a battery cell according to some further embodiments of the present application; Fig. 16 is a schematic representation of the structure of a first electrode sheet of the battery cell according to some further embodiments of the present application; Fig.Figure 17 is a schematic representation of the structure of a first electrode sheet of the battery cell according to some further embodiments of the present application.

[0032] The drawings are not necessarily to scale. Reference symbol list:

[0033] X, thickness direction; Y, width direction; Z, length direction; 1, power-consuming device; 2, battery pack; 3, controller; 4, motor; 5, housing body; 5a, first housing body section; 5b, second housing body section; 5c, receiving compartment; 6, battery module; 7, battery cell; 10, electrode assembly; 11, first electrode sheet; 111, first electrode tab; 1111, first end; 112, first electrode sheet main body; 12, second electrode sheet; 121, second electrode tab; 122, second electrode sheet main body; 13, separator; 20, housing assembly; 21, housing body; 211, first housing section; 212, second housing section; 2121, first wall; 2122, second wall; 213, third housing section; 22, end cap; 31, first electrode terminal; 32, second electrode terminal; 51, first adapter; 61, first conductive element; 611, first conductive section; 612, second conductive section. Detailed descriptions

[0034] The following section describes in detail embodiments of a battery cell, a battery device, and a power-consuming device specifically disclosed in the present application, possibly with reference to the drawings. However, an unnecessarily detailed description can be omitted. For example, a detailed description of known facts and a repeated description of essentially the same structure can be avoided. This is to prevent the following description from becoming unnecessarily lengthy, thus facilitating understanding by those skilled in the art. Furthermore, the drawings and the following description serve to enable those skilled in the art to fully understand the present application and are not intended to limit the subject matter described in the claims.

[0035] The “range” disclosed in the present application is defined in terms of a lower bound and an upper bound. A given range is defined by selecting a lower bound and an upper bound. The selected lower bound and upper bound define the limits of the specific range. The ranges thus defined may or may not include the end values ​​and may be specified in any combination; that is, any lower bound can be combined with any upper bound to form a range. For example, if ranges of 60 to 120 and 80 to 110 are listed for a particular parameter, then ranges of 60 to 110 and 80 to 120 are also conceivable. Furthermore, if minimum range values ​​of 1 and 2 and maximum range values ​​of 3, 4, and 5 are listed, then all of the following ranges are conceivable: 1 to 3, 1 to 4, 1 to 5, 2 to 3, 2 to 4, and 2 to 5.In the present application, unless otherwise specified, a range of numbers "a to b" represents an abbreviation for any combination of real numbers between a and b, where a and b are both real numbers. For example, the range "0 to 5" means that all real numbers between "0 to 5" are listed therein, and "0 to 5" is simply an abbreviation for these number combinations. Furthermore, if a particular parameter is specified as an integer ≥ 2, this is equivalent to disclosing that the parameter is, for example, an integer of 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0036] Unless otherwise stated, all embodiments and optional embodiments of the present application may be combined to form a new technical solution.

[0037] Unless otherwise stated, all technical features and optional technical features of the present application may be combined to form a new technical solution.

[0038] Unless otherwise stated, all steps of the present application may be carried out sequentially or in any order, but preferably sequentially. For example, a method comprising steps (a) and (b) means that the method may include steps (a) and (b) carried out sequentially, or steps (b) and (a) carried out sequentially. Similarly, if it is mentioned that the method may further include step (c), this means that step (c) may be added in any order. For example, the method may include steps (a), (b), and (c), or steps (a), (c), and (b), or steps (c), (a), and (b), etc.

[0039] The term ‘several’ used in the present application refers to two or more (including two).

[0040] In embodiments of the present application, the battery cell may be a secondary battery, wherein the secondary battery is a battery cell that can continue to be used by activating the active material through charging after the discharge of the battery cell.

[0041] The battery cell comprises an electrode array, which includes electrode sheets. During charging, electrons are transported within the electrode sheets. If the electron transport path is too long, this leads to low electronic conductivity and high internal resistance, which negatively impacts fast charging of the battery cell. Particularly at high energy densities, the internal resistance of the battery cell increases further, which also hinders fast charging at high energy densities.

[0042] In view of the aforementioned problems, the embodiments of the present application address, on the one hand, the selection of the dimensions of the positive electrode active material layer within a suitable range to achieve a relatively high energy density of the battery cell. On the other hand, a relatively short electron transport path is realized through a targeted design of the electron transport path, which can effectively reduce the internal resistance of the battery cell and is therefore advantageous for fast charging of the battery cell at high energy density.

[0043] The battery cell of the present application is applicable to various battery devices and power-consuming devices that use the battery cell.

[0044] The power-consuming device could be, for example, a mobile phone, a portable device, a laptop, an electric vehicle, an electric toy, a power tool, a vehicle, a ship, or a spacecraft. Alternatively, the power-consuming device could be, for example, a spacecraft, where the spacecraft includes an airplane, a rocket, a space shuttle, and a spaceship.

[0045] Fig. Figure 1 is a schematic representation of a power-consuming device 1 as an example. The power-consuming device 1 is a pure electric vehicle, a hybrid electric vehicle, or a plug-in hybrid electric vehicle, etc. To meet the power-consuming device 1's requirements for high power and high energy density, a battery pack or battery module can be used.

[0046] Inside the power-consuming device 1, a battery device is arranged, the battery device being located at the bottom, top, or rear of the power-consuming device 1. The battery device can be used to supply power to the power-consuming device 1. For example, the battery device can be used both as an operating power source for the power-consuming device 1 and as a drive power source for the power-consuming device 1, replacing fuel or natural gas wholly or partially to provide the drive for the power-consuming device 1. In the case described in Fig. The battery device shown in Figure 1 is a battery pack.

[0047] The power-consuming device 1 can further comprise a controller 3 and a motor 4, wherein the controller 3 is used to control the battery device in order to supply power to the motor 4, for example to meet the work power requirements of the power-consuming device 1 when starting, navigating and driving.

[0048] The battery apparatus can comprise one or more battery cell assemblies to provide voltage and capacity. The battery cell assembly can comprise multiple battery cells connected in series, parallel, or a mixed configuration via a current collector.

[0049] In some embodiments, a battery cell assembly is generally formed by arranging the multiple battery cells.

[0050] For example, the battery cell arrangement could be a battery module, where the battery module consists of several battery cells arranged and secured to form a self-contained module. For instance, a battery module can be formed by bundling several battery cells together with cable ties.

[0051] As in Fig. As shown in Figure 2, in some embodiments the battery device can be a battery pack 2, wherein the battery pack 2 comprises a box body 5 and one or more battery cell arrangements, the battery cell arrangements being accommodated in the box body 5.

[0052] As an example, the battery cell arrangement can also be incorporated into the box body 5 by attaching several battery cells directly to the box body 5.

[0053] As an example, the box body 5 comprises a first box body section 5a and a second box body section 5b. The box body 5 has a receiving space 5c. The first box body section 5a and the second box body section 5b interlock, creating a closed space within the box body 5 for receiving the battery cell assembly. "Closed" here refers to covering or sealing, which can be either airtight or not. The first box body section 5a can be a top cover or a bottom plate.

[0054] For example, the box body 5 can comprise a top cover, a frame, and a base plate. The top cover and the base plate are each connected to the frame, creating an enclosed space inside the box body 5 to accommodate the battery cell arrangement.

[0055] In some embodiments, the box body 5 can be designed as part of a vehicle chassis. For example, part of the box body 5 can become at least part of a floor of the vehicle, or part of the box body 5 can become at least part of a cross member and a longitudinal member of the vehicle.

[0056] For example, the battery cell arrangement can be a battery module 6, and the battery cell arrangement can be accommodated in the box body 5 by attaching the battery module 6 to the box body 5.

[0057] As in Fig. As shown in Figure 3, the battery module 6 comprises several battery cells 7.

[0058] In some embodiments, the temperature of the external environment in which the battery device is located during the charging process of the battery device from state of charge (SOC) of 0% to 100% room temperature, for example 25°C.

[0059] In some embodiments, the temperature of the external environment in which the battery device is located during the charging process of the battery device or any battery cell 7 of which the battery device consists, changes from the state of charge (SOC) of 10% to 80% room temperature, for example 25°C.

[0060] For example, the charging process of the battery device or of any battery cell 7 of which the battery device consists, from 10% SOC to 80% SOC can be carried out as follows: With a constant current of 7.0 C, charging from 10% SOC to 25% SOC is achieved; With a constant current of 7.0 C, charging from 25% SOC to 30% SOC is achieved; With a constant current of 7.0 C, charging from 30% SOC to 35% SOC is achieved; With a constant current of 7.0 C, it charges from 35% SOC to 40% SOC; With a constant current of 6.7 C, it charges from 40% SOC to 45% SOC; With a constant current of 6.5 C, charging from 45% SOC to 50% SOC is achieved; With a constant current of 6.0 C, charging from 50% SOC to 55% SOC is achieved; With a constant current of 5.8 C, it charges from 55% SOC to 60% SOC; With a constant current of 5.5 C, charging from 60% SOC to 65% SOC is achieved; With a constant current of 5.2 C, it charges from 65% SOC to 70% SOC; With a constant current of 5.0 C, charging from 70% SOC to 75% SOC is achieved; With a constant current of 4.8 C, the battery is charged from 75% SOC to 80% SOC.

[0061] In some embodiments, the charging time of the battery device or of any battery cell 7 comprising the battery device, from a state of charge of 10% to 80%, is 5 to 20 minutes, optionally less than or equal to 12 minutes, and further 5 to 8 minutes. The temperature of the external environment of the battery device at a state of charge of 10% is room temperature, for example 25 °C. For example, the charging time of the battery device from a charge level of 10% to 80% is 20 minutes, 19 minutes, 18 minutes, 17 minutes, 16 minutes, 15 minutes, 14.5 minutes, 14 minutes, 13.5 minutes, 13 minutes, 12.5 minutes, 12 minutes, 11.5 minutes, 11 minutes, 10.5 minutes, 10 minutes, 9.5 minutes, 9 minutes, 8.5 minutes, 8 minutes, 7.5 minutes, 7 minutes, 6.5 minutes, 6 minutes, 5 minutes, or lies in a range consisting of any two of the above values.

[0062] As in the Fig.As shown in Figures 4 to 6, the battery cell 7 comprises an electrode arrangement 10, wherein the electrode arrangement 10 comprises a first electrode sheet 11 and a second electrode sheet 12, one of the first electrode sheet 11 and the second electrode sheet 12 being a positive electrode sheet and the other a negative electrode sheet, wherein the first electrode sheet 11 and the second electrode sheet 12 each comprise an electrode sheet body and at least one electrode tab section, wherein an active material layer is arranged in at least one sub-region of the electrode sheet body, and wherein at least one electrode tab section is connected to the electrode sheet body and projects out of the electrode sheet body along the first direction, wherein at least one part of the electrode tab section is not provided with an active material layer. wherein the active material layer of the positive electrode sheet comprises a positive electrode active material, wherein the positive electrode active material comprises a lithium-containing phosphate with an olivine structure, and the dimension of the electrode sheet main body of the positive electrode sheet along the longitudinal direction Z of the battery cell is 7 320 mm to 650 mm, where the first electrode sheet 11 fulfills the following condition: the maximum value of a 2 + b 2 is between 6000 and 110000, where a in the first electrode sheet 11 along the first direction represents the distance between any point A of the electrode sheet main body and the electrode tab section which is closest to point A in the at least one electrode tab section, in units of mm; wherein b in the first electrode sheet 11 represents along a second direction the distance between point A and the electrode tab section which is closest to point A in at least one electrode tab section, in units of mm, wherein one of the first direction and the second direction is parallel to the longitudinal direction of the first electrode sheet and the other is parallel to the transverse direction of the first electrode sheet.

[0063] For example, the maximum value of a is 2 + b 2 6000, 10000, 15000, 20000, 25000, 30000, 35000, 40000, 45000, 50000, 55000, 60000, 65000, 70000, 75000, 80000, 85000, 90000, 95000, 100000, 105000, 110000 or lies within a range consisting of any two of the above values.

[0064] In the same first electrode sheet 11, there are several points A, and accordingly several values ​​for a result. 2 + b 2 The maximum value of a 2 + b2 This can fundamentally characterize the longest electron transport path in this electrode sheet. Through the targeted design of this maximum value of a 2 + b 2 The electron transport pathway is shortened.

[0065] In the embodiments of the present application, the electrode arrangement 10 can be a stacked electrode arrangement which, compared to a wound electrode arrangement, can accommodate more active material, which contributes to increasing the energy density of the battery cell 7.

[0066] If the dimensions of the electrode sheet main body of the positive electrode sheet along the longitudinal direction Z of battery cell 7 are too small, this results in a low energy density of battery cell 7 that does not meet the requirements. If the dimensions of the electrode sheet main body of the positive electrode sheet along the longitudinal direction Z of battery cell 7 are too large, this results in an excessively high energy density of battery cell 7, but simultaneously in a longer electron transport path and an excessively high internal resistance, which adversely affects fast charging.

[0067] In the embodiments of the present application, the dimensions of the main body of the positive electrode sheet along the longitudinal direction Z of the battery cell 7 lie within the aforementioned range, resulting in a relatively high energy density of the battery cell. However, this high energy density necessitates a high internal resistance of the electrode sheet. Furthermore, the positive electrode active material in the present application comprises a lithium-containing phosphate with an olivine structure and low conductivity, which further increases the internal resistance. To reduce the internal resistance, the electron transport path in the embodiments of the present application is designed such that the electron transport path within the electrode sheet is relatively short, which reduces the internal resistance of the electrode sheet and thus the internal resistance of the battery cell. This is advantageous for fast charging of the battery cell at high energy density.

[0068] For the clarity of this application, the electrode tab section of the first electrode sheet 11 is defined as the first electrode tab 111, and the electrode sheet body of the first electrode sheet 11 is defined as the first electrode sheet body 112. The electrode tab section of the second electrode sheet 12 is defined as the second electrode tab 121, and the electrode sheet body of the second electrode sheet 12 is defined as the second electrode sheet body 122. The electrode terminal that has the same electrical charge as the first electrode tab 111 and is electrically connected to it is the first electrode terminal 31, and the electrode terminal that has the same electrical charge as the second electrode tab 121 and is electrically connected to it is the second electrode terminal 32.

[0069] An active material layer is arranged in at least one sub-region of the electrode sheet body. This can be understood as follows: either the active material layer extends across all sub-regions of the electrode sheet body, or the active material layer is arranged only in certain sub-regions of the electrode sheet body, while an insulating layer may be arranged in other sub-regions. For example, an active material layer is arranged in certain sub-regions of the positive electrode sheet body, while an insulating layer is arranged in the edge regions of the electrode sheet body.

[0070] In at least one sub-region of the electrode tab section, no active material layer is arranged. This can be interpreted as follows: either no active material layer is arranged in any sub-region of the electrode tab section, or no active material layer is arranged in the main regions of the electrode tab section, whereas an active material layer is arranged in the sub-regions of the electrode tab section located towards the main electrode sheet body. For example, an active material layer can be arranged in the sub-regions of the electrode tab section of the negative electrode sheet located towards the main electrode sheet body in order to absorb the active ions from the positive electrode sheet and reduce the risk of lithium plating.

[0071] The first electrode sheet 11 and the second electrode sheet 12 have opposite polarities. If the first electrode sheet 11 is a positive electrode sheet, the second electrode sheet 12 is a negative electrode sheet, the first electrode terminal 31 is a positive electrode terminal and the second electrode terminal 32 is a negative electrode terminal; or if the first electrode sheet 11 is a negative electrode sheet, the second electrode sheet 12 is a positive electrode sheet, the first electrode terminal 31 is a negative electrode terminal and the second electrode terminal 32 is a positive electrode terminal.

[0072] The electrode assembly comprises a positive electrode sheet, a negative electrode sheet, and a separator located between the positive and negative electrode sheets. The following description assumes that the first electrode sheet 11 is configured as a positive electrode sheet and the second electrode sheet 12 as a negative electrode sheet. Of course, the first electrode sheet 11 could be a negative electrode sheet and the second electrode sheet 12 a positive electrode sheet. The main body of the positive electrode sheet comprises a positive electrode current collector section and a positive electrode active material layer arranged on at least one side of the positive electrode current collector section. That is, an active material layer containing a positive electrode active material is the positive electrode active material layer.

[0073] The dimension of the positive electrode active material layer of the positive electrode sheet along the longitudinal direction is 320 mm to 650 mm, for example, 320 mm, 350 mm, 400 mm, 450 mm, 500 mm, 550 mm, 600 mm, 650 mm, or lies within a range consisting of any two of the above values. Optionally, the dimension of the positive electrode active material layer of the positive electrode sheet along the longitudinal direction is 320 mm to 600 mm. If the dimension of the positive electrode active material layer of the positive electrode sheet along the longitudinal direction lies within the above range, both the energy density and the fast-charging performance of the battery cell can be improved simultaneously.

[0074] The dimension of the positive electrode active material layer of the positive electrode sheet along the width direction is 80 mm to 150 mm, for example, 80 mm, 90 mm, 100 mm, 110 mm, 120 mm, 130 mm, 140 mm, 150 mm, or lies within a range consisting of any two of the above values. If the dimension of the positive electrode active material layer of the positive electrode sheet along the width direction is within the above range, both the energy density and the fast-charging performance of the battery cell can be improved simultaneously.

[0075] In the electrode arrangement 10 with a stacked structure, the first electrode sheet 11, the second electrode sheet 12 and the separator 13 are formed into the electrode arrangement 10 by a stacking process and the first electrode sheet 11, the second electrode sheet 12 and the separator 13 are stacked.

[0076] In Fig.Figure 4 represents X as the thickness direction of the battery cell 7. In the stacked structure, the thickness direction of the battery cell 7 is parallel to the thickness direction of the first electrode sheet 11, to the thickness direction of the second electrode sheet 12, and to the thickness direction of the electrode arrangement.

[0077] Y represents the lateral direction of battery cell 7. In the stacked structure, the lateral direction of battery cell 7 is parallel to the lateral direction of the first electrode sheet 11 and to the lateral direction of the electrode arrangement.

[0078] Z represents the longitudinal direction of battery cell 7. In the stacked structure, the longitudinal direction of battery cell 7 is parallel to the longitudinal direction of the first electrode sheet 11 and to the longitudinal direction of the electrode arrangement.

[0079] In the embodiments of the present application, the first direction can be parallel to the width direction Y or length direction Z of the battery cell 7.

[0080] The following describes embodiments in which the first direction runs parallel to the width direction Y of the battery cell 11.

[0081] In some embodiments, the first electrode sheet 11 comprises one or more first electrode tabs 111, wherein the one or more first electrode tabs 111 are arranged on at least one side of the electrode sheet main body along the width direction Y.

[0082] Any point within the first electrode sheet body 112 is defined as point A, where point A is chosen at any location within the first electrode sheet body 112. The arbitrary point can be a point with an area; for example, the area of ​​the point is 0.01 µm². 2 , the area of ​​the spot is much smaller than the area of ​​the electrode tab, and the size of the spot does not fundamentally affect the distance measurement.

[0083] The first electrode tab 111 comprises a first side and a second side that are opposite each other along the first direction. The first side is located near the first electrode sheet main body 112, and the second side is located away from the first electrode sheet main body 112. The distance between point A and the first electrode tab 111 along the first direction is the distance between point A and the first side along the first direction. Fig. 6 the first direction runs parallel to the latitude direction Y of the battery cell 11, and a represents the distance between point A and the first electrode tab 111 along the latitude direction Y.

[0084] One or more first electrode tabs 111 may be present. If there are multiple electrode tabs 111, the first electrode tab 111 that is closest to point A along the second direction is the first electrode tab 111 with the minimum distance to point A along the second direction.

[0085] The first electrode tab 111 nearest to point A is defined as the nearest electrode tab, wherein the nearest electrode tab comprises a first edge and a second edge opposite each other along the second direction, the first edge being located near point A and the second edge being located away from point A. Along the second direction, the distance between point A and the first electrode tab 111 nearest to point A is the distance between point A and the first edge along the second direction.

[0086] The projection of the next electrode tab along the first direction partially overlaps with the projection of the first electrode sheet body 112 along the first direction. In other words, the projection of the next electrode tab along the first direction lies within the projection of the first electrode sheet body 112 along the first direction, where the first direction is parallel to the normal of the projection surface. Point A is any point on the first electrode sheet body 112. If the projection of point A along the first direction lies within the projection of the next electrode tab along the first direction, the distance between point A and the next electrode tab along the second direction can be considered to be 0.If the projection of point A along the first direction lies outside the projection of the next electrode tab along the first direction, it can be assumed that the distance between point A and the next electrode tab along the second direction is greater than 0, where the distance is the distance between point A and the first edge along the second direction.

[0087] For example, one or more first electrode tabs 111 are arranged on one side of the first electrode sheet body 112 along the lateral direction Y. In this case, it is understood that all first electrode tabs 111 are arranged on the same side of the first electrode sheet body 112 along the lateral direction Y. This arrangement helps to increase the space occupied by the electrode arrangement 10 and thereby improve the energy density of the battery cell 7.

[0088] In the case that all first electrode tabs 111 are arranged on the same side of the first electrode sheet main body 112 along the lateral direction Y, the maximum value of a 2 + b 2 6400 to 45000, optionally 6400 to 25000.

[0089] The in Fig. 6 Y1 shown represents the dimension of the first electrode sheet main body 112 along the width direction Y, which can also be understood as the width of the first electrode sheet main body 112.

[0090] For electrons at the same location, multiple transport pathways between them and the electrode contacts can exist. The distance the electron travels along the shortest path is considered the electron transport pathway at that point.

[0091] For electrons at different positions (i.e., electrons at different points A) in the same electrode array, the electron transport distance is recorded for each position. The longest electron transport distance is selected as the maximum value of the electron transport distance. This maximum value is determined by the maximum value of a 2 + b 2 characterized by the targeted interpretation of this maximum value of a 2 + b 2 The electron transport path is shortened, which reduces the internal resistance and improves the fast charging performance of the battery cell.

[0092] In Fig.6. For electrons at the same point A2, multiple transport pathways such as C1 and C2 can exist (only C1 and C2 are shown in the figure; other transport modes are not excluded). If pathway C1 is longer than pathway C2, the transport pathway for electrons at point A2 is defined as pathway C2. If C1 and C2 are the same length, the transport pathway for electrons at point A2 can be defined as either pathway C1 or pathway C2.

[0093] Since the first electrode tabs 111 are arranged on the same side of the first electrode sheet body 112, a corresponds specifically to the dimension of the first electrode sheet body 112 along the first direction. Since the first direction is parallel to the lateral direction Y, a represents the dimension of the first electrode sheet body 112 along the lateral direction Y. That is, a is equal to the width Y1 of the first electrode sheet body 112. Consequently, Y1 corresponds to the distance between point A2 and the electrode tab section along the first direction that is closest to point A2 in at least one electrode tab section.

[0094] The second direction runs parallel to the longitudinal direction Z of the first electrode plate 11. b1 represents the distance between point A2 and an adjacent first electrode plate 111 along the longitudinal direction Z, and b2 represents the distance between point A2 and another adjacent first electrode plate 111 along the longitudinal direction Z. If b1 is greater than b2, then b2 represents the distance between point A2 and the electrode plate segment along the second direction that is closest to point A2 in at least one electrode plate segment. In this case, the electron transport path at point A2 is defined as distance C2. If b1 equals b2, then b1 or b2 can represent the distance between point A2 and the electrode tab section along the second direction that is closest to point A2 in at least one electrode tab section. In this case, the electron transport path at point A2 is defined as path C1 or path C2.

[0095] For one and the same first electrode sheet 11, there are several positions, for example A1 and A2, where for electrons at point A1, i.e. electrons at the edge of the first electrode sheet main body 112, the following applies: a is equal to the width Y1 of the first electrode sheet main body 112, b3 represents the distance between point A1 and the adjacent first electrode tab 111 along the longitudinal direction Z, and C3 represents the electron transport pathway at point A1.

[0096] Using the electron transport path C2 of the electron at point A2 as an example: if C2 is greater than or equal to C3, then C2 represents the longest electron transport path in the first electrode sheet 11, and the maximum value of a 2 + b 2 corresponds to the square of C2; if C2 is smaller than C3, then C3 represents the longest electron transport path in the first electrode sheet 11, and the maximum value of a 2 + b 2 corresponds to the square of C3.

[0097] As in Fig. As shown in Figure 7, for example, in the case where the first electrode sheet 11 comprises several first electrode tabs 111, several first electrode tabs 111 are arranged on both sides of the first electrode sheet main body 112 along the lateral direction Y.

[0098] In the case where several first electrode tabs 111 are arranged on both sides of the first electrode sheet main body 112 along the lateral direction Y, the maximum value of a 2 + b 2 6400 to 45000, optionally 6400 to 25000.

[0099] The in Fig. Figure 7 Y1 represents the dimension of the first electrode sheet main body 112 along the width direction Y, which can also be understood as the width of the first electrode sheet main body 112.

[0100] In Fig. 7. For electrons at the same point A2, multiple transport pathways such as C1, C2, C3, and C4 can exist. If pathway C2 is the shortest, the transport pathway for electrons at point A2 is defined as pathway C2.

[0101] Since the first electrode tabs 111 are arranged on both sides of the first electrode sheet body 112, a corresponds specifically to half the dimension of the first electrode sheet body 112 along the first direction. Since the first direction is parallel to the lateral direction Y, a represents half the dimension of the first electrode sheet body 112 along the lateral direction Y. That is, a is equal to the width Y1 / 2 of the first electrode sheet body 112. Consequently, Y1 / 2 corresponds to the distance between point A2 and the electrode tab section along the first direction that is closest to point A2 in at least one electrode tab section.

[0102] The second direction runs parallel to the longitudinal direction Z of the first electrode plate 11. b1 represents the distance between point A2 and an adjacent first electrode plate 111 along the longitudinal direction Z, and b2 represents the distance between point A2 and another adjacent first electrode plate 111 along the longitudinal direction Z. If b1 is greater than b2, then b2 represents the distance between point A2 and the electrode plate segment along the second direction that is closest to point A2 in at least one electrode plate segment. In this case, the electron transport path at point A2 is defined as distance C2. If b1 equals b2, then b1 or b2 can represent the distance between point A2 and the electrode tab section along the second direction that is closest to point A2 in at least one electrode tab section. In this case, the electron transport path at point A2 is defined as path C1 or path C2.

[0103] For one and the same first electrode sheet 11, there are several positions, for example A1 and A2, where for electrons at point A1, i.e. electrons at the edge of the first electrode sheet main body 112, the following applies: a3 is equal to the width Y1 / 2 of the first electrode sheet main body 112, b3 represents the distance between point A1 and the adjacent first electrode tab 111 along the longitudinal direction Z, and C5 represents the electron transport pathway at point A1.

[0104] Using the electron transport path C2 of the electron at point A2 as an example: if C2 is greater than or equal to C5, then C2 represents the longest electron transport path in the first electrode sheet 11, and the maximum value of a 2 + b 2 corresponds to the square of C2; if C2 is smaller than C5, then C5 represents the longest electron transport path in the first electrode sheet 11, and the maximum value of 2 + b 2 corresponds to the square of C5.

[0105] Regardless of whether all first electrode tabs 111 are arranged on the same side of the first electrode sheet body 112 along the lateral direction Y, or whether all first electrode tabs 111 are arranged on both sides of the first electrode sheet body 112 along the lateral direction Y, the first electrode tabs 111 arranged on the same side of the first electrode sheet body 112 can be configured in a plurality of, for example, two, three, four, five, six, etc., optionally four. This arrangement is advantageous for the uniform distribution of electrons in the first electrode sheet 11 and contributes to improving the fast-charging performance.

[0106] Optionally, the distance between two adjacent electrode tab sections along the longitudinal direction Z is greater than 0 and less than or equal to 300 mm, for example 100 mm, 120 mm, 140 mm, 150 mm, 160 mm, 180 mm, 200 mm, 220 mm, 240 mm, 250 mm, 260 mm, 280 mm, 300 mm, or lies within a range consisting of any two of the above values. The in Fig. Figure 7 Z1 represents the distance between two adjacent electrode tab sections along the longitudinal direction Z.

[0107] As in Fig. As shown in Figure 8, in some embodiments the first electrode sheet 11 fulfills the following condition: n*W1 / W2 is 0.5 to 1.0, wherein n represents the number of all electrode tab sections on the same side of the electrode sheet main body, W1 represents the average dimension of the electrode tab section along the second direction, and W2 represents the dimension of the electrode sheet main body along the second direction.

[0108] For example, n*W1 / W2 is 0.5, 0.55, 0.6, 2 / 3, 0.7, 0.75, 0.8, 0.85, 0.9, 1.0 or lies in a range consisting of any two of the above values.

[0109] In Fig. 8. The first direction runs parallel to the lateral direction Y of battery cell 11, where n is 1. If the first direction runs parallel to the longitudinal direction Z of battery cell 11, the condition that n*W1 / W2 is between 0.5 and 1.0 is also satisfied and is not repeated here. If the electrode arrangement 10 has a wound structure, the condition that n*W1 / W2 is between 0.5 and 1.0 is also satisfied and is not repeated here.

[0110] In the embodiments of the present application, the first electrode sheet 11 further satisfies the condition that n*W1 / W2 is 0.5 to 1.0. This results in a relatively large contact area between the electrode tab section and the main body of the electrode sheet, as well as a relatively large current passage area of ​​the electrode tab section, which is advantageous for reducing the DC resistance, reducing heat generation, and improving the fast-charging performance of the battery cell.

[0111] W1 represents the average dimension of the first electrode tab 111 along the second direction.

[0112] If the first electrode tab 111 has an irregular structure, for example along the first direction, its dimensions gradually increase along the second direction. In this case, the dimensions of several points on the first electrode tab 111 along the second direction can be measured to calculate an average dimension value for the first electrode tab 111 along the second direction. Of course, the dimensions of all points on the first electrode tab 111 along the second direction may be the same. In this case, the value can be used as the average dimension value for the first electrode tab 111.

[0113] One or more first electrode tabs 111 can be provided, n being, for example, 1 to 4. If several first electrode tabs 111 are provided, the average dimensions of each first electrode tab 111 can be measured separately, the average dimensions of each can be added together and divided by the number of first electrode tabs 111 to calculate the average dimension of the first electrode tab 111.

[0114] The first electrode tab 111 is connected to the first electrode sheet main body 112, and the first electrode tab 111 includes a first end 1111 that is connected to the first electrode sheet main body 112. If n*W1 / W2 is within the range above, this means that the cross-section of the first end 1111 is relatively large along the thickness direction of the first electrode tab 111 itself, the contact area between the first electrode tab 111 and the first electrode sheet main body 112 is relatively large, and the first electrode tab 111 has a high current-carrying capacity, which can improve the performance and cycle life of the battery cell 7.

[0115] Optionally, the first electrode tab 111 and the current collection section of the first electrode sheet main body 112 are designed as a single-piece structure, so that the internal resistance of the first electrode sheet 11 is low, which can further improve the performance and cycle performance of the battery cell 7.

[0116] As in Fig.As shown in Figure 9, in some embodiments, the distance c, in units of mm, between any point B of the main body of the electrode sheet and the electrode tab section closest to point B in at least one electrode tab section is defined in the second electrode sheet 12 along the first direction. Along the second direction, the distance d, in units of mm, between point B and the electrode tab section closest to point B in at least one electrode tab section is defined in the second electrode sheet 12. One of the first or the second direction runs parallel to the longitudinal direction of the first electrode sheet, and the other runs parallel to the lateral direction of the first electrode sheet. The maximum value of c 2 + d 2 The number ranges from 6000 to 110000.

[0117] If the second electrode sheet 12 in the embodiments of the present application meets the above-mentioned conditions, the electron transport path is relatively short, which can effectively reduce the internal resistance of the battery cell, and each electrode tab accepts a smaller current and the current distribution is more uniform, which is advantageous for fast charging of the battery cell.

[0118] In the embodiments of the present application, the number and arrangement of the second electrode tabs 121 correspond to those of the first electrode tabs 111, which will not be discussed again here. The structure of the second electrode sheet 12 is identical to that of the first electrode sheet 11, which will not be discussed again here.

[0119] The following describes embodiments in which the first direction runs parallel to the longitudinal direction of the battery cell 11.

[0120] As in Fig.As shown in Figure 10, the first electrode sheet 11 in some embodiments comprises one or more first electrode tabs 111, wherein the one or more first electrode tabs 111 are arranged on at least one side of the first electrode sheet main body 112 along the longitudinal direction Z.

[0121] For example, one or more first electrode tabs 111 are arranged on one side of the first electrode sheet main body 112 along the longitudinal direction Z. In this case, it is understood that all first electrode tabs 111 are arranged on the same side of the first electrode sheet main body 112 along the longitudinal direction Z.

[0122] In the case that all first electrode tabs 111 are arranged on the same side of the first electrode sheet main body 112 along the longitudinal direction Z, the maximum value of a 2 + b 2 25600 to 110000, optionally 25600 to 90000.

[0123] The in Fig. Figure 10 Z2 represents the dimension of the first electrode sheet main body 112 along the longitudinal direction Z, which can also be understood as the length of the first electrode sheet main body 112.

[0124] In Fig. 10. For electrons at the same point A2, several transport pathways such as C1 and C2 can exist (only C1 and C2 are shown in the figure; other transport modes are not excluded). If pathway C1 is longer than pathway C2, the transport distance of the electrons at point A2 is defined as the length of C2. If C1 and C2 are the same length, the transport distance of the electrons at point A2 can be defined as either the length of C1 or C2.

[0125] Since the first electrode tabs 111 are arranged on the same side of the first electrode sheet body 112, a corresponds specifically to the dimension of the first electrode sheet body 112 along the first direction. Since the first direction is parallel to the longitudinal direction Z, a represents the dimension of the first electrode sheet body 112 along the longitudinal direction Z. That is, a is equal to the length Z2 of the first electrode sheet body 112. Consequently, Z2 corresponds to the distance between point A2 and the electrode tab section along the first direction that is closest to point A2 in at least one electrode tab section.

[0126] The second direction runs parallel to the latitude direction Y of the first electrode plate 11. b1 represents the distance between point A2 and an adjacent first electrode plate 111 along the latitude direction Y, and b2 represents the distance between point A2 and another adjacent first electrode plate 111 along the latitude direction Y. If b1 is greater than b2, then b2 represents the distance between point A2 and the electrode plate segment along the second direction that is closest to point A2 in at least one electrode plate segment. In this case, the electron transport path at point A2 is defined as distance C2. If b1 equals b2, then b1 or b2 can represent the distance between point A2 and the electrode tab section along the second direction that is closest to point A2 in at least one electrode tab section. In this case, the electron transport path at point A2 is defined as path C1 or path C2.

[0127] For one and the same first electrode sheet 11, there are several positions, for example A1 and A2, where for electrons at point A1, i.e. electrons at the edge of the first electrode sheet main body 112, the following applies: a is equal to the length Z2 of the first electrode sheet main body 112, b3 represents the distance between point A1 and the adjacent first electrode tab 111 along the latitude direction Y, and C3 represents the electron transport pathway at point A1.

[0128] Using the electron transport path C2 of the electron at point A2 as an example: if C2 is greater than or equal to C3, then C2 represents the longest electron transport path in the first electrode sheet 11, and the maximum value of a 2 + b 2 corresponds to the square of C2; if C2 is smaller than C3, then C3 represents the longest electron transport path in the first electrode sheet 11, and the maximum value of a 2 + b 2 corresponds to the square of C3.

[0129] As in Fig. As shown in Figure 11, for example, in the case that the first electrode sheet 11 comprises several first electrode tabs 111, the several first electrode tabs 111 are arranged on both sides of the first electrode sheet main body 112 along the longitudinal direction Z.

[0130] Optionally, the multiple first electrode tabs 111 are arranged on both sides of the first electrode sheet main body 112 along the longitudinal direction Z. This arrangement can shorten the transport path of the electrons in the first electrode sheet 11, which contributes to improving the fast charging performance.

[0131] In the case where several first electrode tabs 111 are arranged on both sides of the first electrode sheet main body 112 along the longitudinal direction Z, the maximum value of a 2 + b 2 25600 to 110000, optionally 25600 to 90000.

[0132] The in Fig. Figure 11 Z3 represents the dimension of the first electrode sheet main body 112 along the longitudinal direction Z, which can also be understood as the length of the first electrode sheet main body 112.

[0133] In Fig.11. For electrons at the same point A, multiple transport pathways such as C1 and C2 can exist. If pathway C2 is the shortest, the transport pathway for electrons at point A is defined as pathway C2.

[0134] Since the first electrode tabs 111 are arranged on both sides of the first electrode sheet main body 112, a corresponds specifically to half the dimension of the first electrode sheet main body 112 along the first direction. Since the first direction is parallel to the longitudinal direction Z, a represents half the dimension of the first electrode sheet main body 112 along the longitudinal direction Z. That is, a is equal to the length Z3 / 2 of the first electrode sheet main body 112. Consequently, Z3 / 2 corresponds to the distance between point A and the electrode tab segment along the first direction that is closest to point A in at least one electrode tab segment.

[0135] If only one first electrode tab 111 is present on the same side and the second direction runs parallel to the lateral direction Y of the first electrode sheet 11, then b represents the distance between point A and the first electrode tab 111 along the lateral direction Y, and b represents the distance between point A and the electrode tab segment along the second direction that is closest to point A in at least one electrode tab segment. In this case, the distances C1 and C2 are identical, and both can be considered the longest electron transport path in the first electrode sheet 11. The maximum value of a 2 + b 2 corresponds to the square of C1.

[0136] Regardless of whether all first electrode tabs 111 are arranged on the same side of the first electrode sheet body 112 along the lateral direction Y, or whether all first electrode tabs 111 are arranged on both sides of the first electrode sheet body 112 along the lateral direction Y, the first electrode tabs 111 arranged on the same side of the first electrode sheet body 112 can be configured in a plurality of, for example, two, three, four, five, six, etc. This arrangement is advantageous for the uniform distribution of electrons in the first electrode sheet 11 and contributes to improved fast-charging performance. This arrangement can further shorten the electron transport path and effectively reduce the internal resistance of the battery cell. In addition, each electrode tab accepts a lower current, and the current distribution is more uniform.

[0137] Optionally, the distance between two adjacent electrode tab sections along the lateral direction Y is greater than 0 and less than or equal to 300 mm, for example, 100 mm, 120 mm, 140 mm, 150 mm, 160 mm, 180 mm, 200 mm, 220 mm, 240 mm, 250 mm, 260 mm, 280 mm, 300 mm, or lies within a range consisting of any two of the above values. This arrangement can further shorten the electron transport path and effectively reduce the internal resistance of the battery cell. In addition, each electrode tab accepts a lower current, and the current distribution is more uniform. Fig. Figure 10 Y2 represents the distance between two adjacent electrode tab sections along the lateral direction Y. [Electrolyte solution]

[0138] During the charging and discharging process of the battery cell, active ions, such as lithium ions, are intercalated and deintercalated between the positive and negative electrode sheets, and the electrolyte solution takes on the task of conducting the active ions between the positive and negative electrode sheets.

[0139] The electrolyte salt comprises a lithium salt, specifically lithium bis(fluorosulfonyl)imide, and may further include lithium hexafluorophosphate (LiPF6). The aforementioned lithium salt contributes to increasing the lithium-ion conductivity of the electrolyte solution and improving the fast-charging capability of the battery cell.

[0140] Optionally, the ratio of the mass fraction of lithium hexafluorophosphate to the mass fraction of lithium bis(fluorosulfonyl)imide, based on the mass of the electrolyte solution, is 0.5 to 4, optionally 1.2 to 2.0. The lithium salt contributes to increasing the lithium ion conductivity of the electrolyte solution and improving the fast-charging capability of the battery cell.

[0141] For example, the ratio of the mass fraction of lithium hexafluorophosphate to the mass fraction of lithium bis(fluorosulfonyl)imide is 0.5, 0.7, 0.9, 1.1, 1.3, 1.5, 1.7, 1.9, 2.1, 2.3, 2.5, 2.7, 2.9, 3.1, 3.3, 3.5, 3.7, 3.9, 4.0 or lies in a range consisting of any two of the above values.

[0142] In the embodiments of the present application, the mass fraction of lithium bis(fluorosulfonyl)imide, based on the mass of the electrolyte solution, is 1% to 15%, optionally 3% to 12%.

[0143] For example, the mass fraction of lithium bis(fluorosulfonyl)imide, based on the mass of the electrolyte solution, is 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, or lies in a range consisting of any two of the above values.

[0144] In some embodiments, the mass fraction of the lithium salt, based on the mass of the electrolyte solution, is 13% to 20%, for example 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, or lies in a range consisting of any two of the above values.

[0145] In some embodiments, the conductivity of the electrolyte solution at room temperature is 10 mS / cm to 13 mS / cm. For example, the conductivity of the electrolyte solution at room temperature is 10 mS / cm, 10.5 mS / cm, 11 mS / cm, 11.5 mS / cm, 12 mS / cm, 12.5 mS / cm, 13 mS / cm, or lies within a range consisting of any two of the above values.

[0146] If the conductivity of the electrolyte solution at room temperature, for example 25 °C, is within the range mentioned above, the migration rate of lithium ions in the electrolyte solution is relatively high, which can further reduce the internal resistance of the battery cell, thereby reducing heat generation and improving the fast charging performance of the battery cell.

[0147] In the embodiments of the present application, the conductivity of the electrolyte solution at room temperature, for example 25 °C, is the ionic conductivity, which can be determined using devices and methods known in the art, for example with reference to the industry standard HG-T 4067-2015.

[0148] In some embodiments, the organic solvent comprises a carbonate solvent.

[0149] Optionally, the mass fraction of the carbonate solvent in the electrolyte solution is 10% to 80%. For example, the mass fraction of the carbonate solvent in the organic solvent is 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 60%, 70%, 80%, or lies within any two of the values ​​mentioned above. The carbonate solvent with the mass fraction mentioned above can further improve the conductivity of the electrolyte solution at room temperature, which has a positive effect on the migration of lithium ions and thus improves the fast-charging performance of the battery cell.

[0150] Optionally, the carbonate solvent comprises one or more of ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate, and ethyl methyl carbonate. Optionally, the carbonate solvent also comprises one or more of dimethyl carbonate and ethylene carbonate. Optionally, the carbonate solvent may also comprise dimethyl carbonate. The aforementioned carbonate solvent and the chain-like carboxylic acid ester solvent are used together to improve the conductivity of the electrolyte solution at room temperature, which has a positive effect on lithium ion migration and thus improves the fast-charging performance of the battery cell.

[0151] In some embodiments, the organic solvent also comprises a chain-like carboxylic acid ester solvent.

[0152] Optionally, the mass fraction of the chain-like carboxylic acid ester solvent in the electrolyte solution is 5% to 30%. For example, the mass fraction of the chain-like carboxylic acid ester solvent is 5%, 10%, 15%, 20%, 25%, 30%, or lies within a range consisting of any two of the values ​​mentioned above.

[0153] If the mass fraction of the chain-like carboxylic acid ester solvent is within the range mentioned above, the viscosity of the electrolyte system is relatively low, which has a positive effect on the migration of lithium ions and thus improves the fast charging performance of the battery cell.

[0154] In some embodiments, the chain-like carboxylic acid ester solvent comprises a compound represented by formula I, where in Formula I, R1 comprises a hydrogen atom, a C1 to C5 alkyl group or a halogenated C1 to C5 alkyl group, R2 comprises a C1 to C5 alkyl group or a halogenated C1 to C5 alkyl group.

[0155] The aforementioned chain-like carboxylic acid ester solvent exhibits high electrical conductivity, which has a positive effect on improving the fast-charging capability of the battery cell.

[0156] Optionally, R1 comprises a hydrogen atom, a C1 to C3 alkyl group, or a halogenated C1 to C3 alkyl group. Furthermore, optionally, R1 comprises a hydrogen atom, a halogen atom, a C1 to C2 alkyl group, or a halogenated C1 to C2 alkyl group.

[0157] Optionally, R2 comprises a C1 to C3 alkyl group or a halogenated C1 to C3 alkyl group. Furthermore, optionally, R2 comprises a C1 to C2 alkyl group or a halogenated C1 to C2 alkyl group.

[0158] In the above embodiments, the halogenated alkyl group comprises one or more fluoroalkyl groups, chloroalkyl groups, bromoalkyl groups, and iodoalkyl groups. Optionally, the halogenated alkyl group comprises a fluoroalkyl group.

[0159] For example, the chain-like carboxylic acid ester solvent comprises one or more of the compounds represented by formulas I-1 to I-8,

[0160] In some embodiments, the electrolyte solution also contains an additive, which may include a film-forming additive for the negative electrode, a film-forming additive for the positive electrode, and an additive that can improve certain battery performance characteristics, such as an additive that improves the battery's overcharge behavior, an additive that improves the battery's high-temperature performance, and an additive that improves the battery's low-temperature performance.

[0161] In some embodiments, the additive contains one or more carbonate additives, sulfur-containing additives, and optionally at least two of these. The aforementioned additive can improve the performance of the interfacial films on the positive electrode side and / or the negative electrode side, which has a positive effect on improving the fast-charging performance of the battery cell and its cycle life.

[0162] In some embodiments, the mass fraction of the additive in the electrolyte solution is 0.5% to 6%. For example, the mass fraction of the additive in the electrolyte solution is 0.5%, 1.0%, 1.5%, 2.0%, 2.5%, 3.0%, 3.5%, 4.0%, 4.5%, 5.0%, 5.5%, 6%, or lies in a range consisting of any two of the above values.

[0163] The aforementioned organic solvent, such as the chain-like carboxylic acid ester solvent, can form acids at high temperatures that attack the solid electrolyte interface film (SEI film) on the negative electrode surface. In contrast, the additive can form a dense and uniform SEI film on the negative electrode side, effectively repairing the SEI film and providing excellent protection for the negative electrode active material. This positively impacts the fast-charging performance of the battery cell and improves its cycle life.

[0164] For example, the carbonate additive comprises one or more of vinylene carbonate (VC) and fluoroethylene carbonate (FEC). Optionally, the carbonate additive comprises vinylene carbonate (VC) and fluoroethylene carbonate (FEC).

[0165] Vinylene carbonate VC can form a dense and uniform SEI film on the negative electrode side, effectively repairing the SEI film and providing excellent protection for the negative electrode active material, which positively impacts the improvement of the battery cell's fast charging performance and cycle performance.

[0166] Fluoroethylene carbonate (FEC) can form a relatively low impedance SEI film on the negative electrode side, effectively repairing the SEI film and providing excellent protection for the negative electrode active material, which positively impacts the improvement of the battery cell's fast charging performance and cycle performance.

[0167] For example, the sulfur-containing additive includes one or more of ethylene sulfate DTD, bis(ethylene sulfate) 2-DTD, butylene sulfite BS, 1,3-propanesultone PS, ethylene sulfite ES and methylenemethanedisulfonate MMDS, optionally 1,3-propanesultone PS.

[0168] The sulfur-containing additive can effectively repair the SEI film and provides excellent protection for the negative electrode active material, which has a positive effect on improving the fast charging performance of the battery cell and the cycle performance.

[0169] For example, the additive includes one or more of vinylene carbonate, fluoroethylene carbonate and 1,3-propanesulfonate.

[0170] Optionally, the mass fraction of vinylene carbonate (VC) in the electrolyte solution is 0.5% to 3.0%, for example, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1.0%, 1.1%, 1.2%, 1.3%, 1.4%, 1.5%, 1.6%, 1.7%, 1.8%, 1.9%, 2.0%, 2.5%, 3.0%, or lies within any two of the above values. If the mass fraction of vinylene carbonate (VC) in the electrolyte solution is within the above range, the SEI film can be effectively repaired and the negative electrode active material is excellently protected, which positively impacts the fast-charging performance of the battery cell and its cycle life.

[0171] Optionally, the mass fraction of fluoroethylene carbonate (FEC) in the electrolyte solution is 0.2% to 2.5%, for example, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1.0%, 1.5%, 2.0%, 2.5%, or lies within any two of the above values. If the mass fraction of FEC in the electrolyte solution is within the above range, the SEI film can be effectively repaired and the negative electrode active material is excellently protected, which has a positive effect on improving the fast-charging performance of the battery cell and its cycle life.

[0172] Optionally, the mass fraction of 1,3-propanesulfonate (PS) in the electrolyte solution is 0.5% to 2.5%, for example, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1.0%, 1.1%, 1.2%, 1.3%, 1.4%, 1.5%, 1.6%, 1.7%, 1.8%, 1.9%, 2.0%, 2.5%, or lies within any two of the above values. If the mass fraction of 1,3-propanesulfonate (PS) in the electrolyte solution is within the above range, the SEI film can be effectively repaired and the negative electrode active material is excellently protected, which has a positive effect on improving the fast-charging performance of the battery cell and its cycle life.

[0173] In the embodiments of the present application, the types and concentrations of the inorganic components / lithium salts in the electrolyte solution have meanings known in the art and can be determined using devices and methods known in the art. For example, the inorganic components / lithium salts in the electrolyte solution can be analyzed qualitatively or quantitatively by ion chromatography in accordance with the standard JY / T020-1996 "General rules for ion chromatography analysis methods".In the embodiments of the present application, a newly prepared electrolyte solution can be taken as a sample, a free electrolyte solution from a fresh battery can be taken as a sample, or a completely discharged battery (it has been discharged to the discharge cut-off voltage, so that the state of charge of the battery is approximately 0% SOC) can be reverse disassembled and the free electrolyte solution obtained from the battery taken as a sample. The sample is analyzed using the ion chromatography analytical method.

[0174] In the embodiments of the present application, the types and concentrations of the organic components in the electrolyte solution have meanings known in the art and can be determined using devices and methods known in the art. For example, reference can be made to GB / T9722-2006 "General rules for the gas chromatography of chemical reagents" to carry out a qualitative and quantitative analysis of organic components in the electrolyte solution by means of gas chromatography.

[0175] In the embodiments of the present application, the components are classified after quantitative and qualitative analysis of all components in the electrolyte solution. The chain-like carboxylic acid ester solvents and carbonate solvents (such as ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate, and ethyl methyl carbonate) are classified as constituents of the organic solvent. The mass fraction of the individual components is calculated based on the mass of the electrolyte solution at 100%.

[0176] The carbonate additive (such as vinylene carbonate, fluoroethylene carbonate) and the sulfur-containing additive are used as additives in the electrolyte solution. The mass fraction of each component is calculated based on the mass of the electrolyte solution at 100%. [Housing arrangement]

[0177] In some embodiments, the battery cell 7 further comprises a housing arrangement 20, and the housing arrangement 20 has a receiving space for receiving the electrode arrangement 10 and the electrolyte solution.

[0178] In some embodiments, the housing arrangement 20 comprises a housing, a first electrode connection 31 and a second electrode connection 32, wherein the first electrode connection 31 and the second electrode connection 32 are arranged on the housing.

[0179] The housing can be a steel housing, an aluminum housing, a plastic housing (e.g., made of polypropylene), a composite metal housing (e.g., a copper-aluminum composite housing), or an aluminum-plastic foil. In some embodiments, the housing can have a sealed or an unsealed structure. If, for example, the housing has an unsealed structure, it serves to protect the electrode assembly 10, with a sealing pouch positioned between the housing and the electrode assembly 10 to enclose the electrode assembly 10 and the electrolyte. In particular, the sealing pouch can be a pouch-shaped insulating element or an aluminum-plastic foil. If the housing has a sealed structure, it is used to encapsulate the electrode assembly 10 and other components such as the electrolyte.

[0180] For example, battery cell 7 can be a cylindrical battery cell, a prismatic battery cell, a pouch battery cell, or a battery cell of other shapes, wherein the prismatic battery cell includes a square battery cell, a leaf-shaped battery cell, and a polygonal battery, such as a hexagonal battery. The present application does not impose any specific restrictions in this regard. Housing

[0181] In some embodiments, the housing comprises an end cap 22 and a housing body 21, wherein the housing body 21 is provided with an opening and the end cap 22 covers the opening. The housing body 21 may be provided with one or more openings. One or more end caps 22 may be provided.

[0182] The first electrode connection 31 and the second electrode connection 32 can be arranged on the housing body 21, or the first electrode connection 31 and the second electrode connection 32 can be arranged on the end cover 22. Optionally, the first electrode connection 31 and the second electrode connection 32 are arranged on the end cover 22.

[0183] The first electrode connection 31 and the second electrode connection 32 can be arranged simultaneously on the same end cap 22. For example, a single end cap 22 is provided, wherein the first electrode connection 31 and the second electrode connection 32 are arranged at a distance from each other on this end cap 22. In another example, two end caps 22 are provided, wherein the two end caps 22 are arranged opposite each other, each end cap 22 being provided with a first electrode connection 31 and a second electrode connection 32.

[0184] The first electrode connection 31 and the second electrode connection 32 are arranged on different end caps 22. For example, two end caps 22 are provided, wherein the two end caps 22 are arranged opposite each other, with the first electrode connection 31 on one of the end caps 22 and the second electrode connection 32 on the other end cap 22.

[0185] The shape of the housing body 21 can be determined according to the specific shape of the electrode assembly 10. For example, if the electrode assembly 10 has a cylindrical structure, a housing body 21 with a cylindrical structure can be selected; if the electrode assembly 10 has a cuboid structure, a housing body 21 with a cuboid structure can be selected. Optionally, both the electrode assembly 10 and the housing body 21 can have the cuboid structure.

[0186] In some embodiments, the housing body 21 comprises two first housing sections 211, a second housing section 212, and a third housing section 213, wherein the two first housing sections 211 are opposite each other along the thickness direction X of the battery cell 7, the second housing section 212 and the third housing section 213 are opposite each other and the second housing section 212 and the third housing section 213 are connected by the first housing section 211, and the second housing section 212 comprises a first wall 2121 and a second wall 2122, which are arranged continuously along the thickness direction X, wherein the first wall 2121 and the second wall 2122 are welded together. The welding of the first wall 2121 and the second wall 2122 can be carried out specifically by butt welding or laser welding, optionally by butt welding.Since the second housing section 212 has a relatively small area and therefore a small extent, the risk of a leak of the battery cell 7 can be reduced by arranging the weld seam on the second housing section 212.

[0187] When installing the battery cell 7 in the housing of the battery device, the battery cell 7 is arranged inside the housing, the housing comprising a first housing section and a second housing section, the first housing section covering the second housing section; the second housing section 212 being arranged opposite the first housing section, and the second housing section 212 being located near the first housing section, while the third housing section 213 being located near the second housing section. When installing the battery device in the power-consuming device, the first housing section can be arranged vertically above the second housing section, and the second housing section 212 should be arranged with its weld seam facing upwards, thereby reducing the risk of leakage of the battery cell 7.

[0188] In some embodiments, the dimension of the battery cell 7 along the thickness direction X is 10 mm to 30 mm, for example 10 mm, 12 mm, 14 mm, 15 mm, 16 mm, 18 mm, 20 mm, 22 mm, 24 mm, 25 mm, 26 mm, 28 mm, 30 mm or lies in a range consisting of any two of the above values.

[0189] The dimension of battery cell 7 along the thickness direction X can characterize the thickness of battery cell 7; in other words, the thickness of battery cell 7 is between 10 mm and 30 mm. If the thickness of battery cell 7 is within the above range, the thickness of battery cell 7 is relatively small, which contributes to rapid heat dissipation within the battery cell 7 and reduces the risk of thermal runaway.

[0190] In some embodiments, the thickness of the housing body 21 is 0.1 mm to 0.5 mm, for example 0.1 mm, 0.12 mm, 0.14 mm, 0.15 mm, 0.16 mm, 0.17 mm, 0.18 mm, 0.19 mm, 0.2 mm, 0.21 mm, 0.22 mm, 0.23 mm, 0.24 mm, 0.25 mm, 0.26 mm, 0.27 mm, 0.28 mm, 0.29 mm, 0.3 mm, 0.31 mm, 0.32 mm, 0.33 mm, 0.34 mm, 0.35 mm, 0.36 mm, 0.37 mm, 0.38 mm, 0.39 mm, 0.4 mm, 0.41 mm, 0.42 mm, 0.43 mm, 0.44 mm, 0.45 mm, 0.46 mm, 0.47 mm, 0.48 mm, 0.49 mm, 0.5 mm, or lies within a range consisting of any two of the above values. Optionally, the thickness of the housing body is 0.3 mm to 0.4 mm.

[0191] If the thickness of the housing body 21 is within the above range, the housing body 21 is relatively thin, which promotes rapid heat dissipation from the housing body 21.

[0192] For example, the thickness of the first housing section 211 is 0.1 mm to 0.5 mm, for example 0.1 mm, 0.12 mm, 0.14 mm, 0.15 mm, 0.16 mm, 0.17 mm, 0.18 mm, 0.19 mm, 0.2 mm, 0.21 mm, 0.22 mm, 0.23 mm, 0.24 mm, 0.25 mm, 0.26 mm, 0.27 mm, 0.28 mm, 0.29 mm, 0.3 mm, 0.31 mm, 0.32 mm, 0.33 mm, 0.34 mm, 0.35 mm, 0.36 mm, 0.37 mm, 0.38 mm, 0.39 mm, 0.4 mm, 0.41 mm, 0.42 mm, 0.43 mm, 0.44 mm, 0.45 mm, 0.46 mm, 0.47 mm, 0.48 mm, 0.49 mm, 0.5 mm, or lies within a range consisting of any two of the above values. Optionally, the thickness of the housing body is 0.3 mm to 0.4 mm.

[0193] For example, the thickness of the second housing section 212 is 0.1 mm to 0.5 mm, for example 0.1 mm, 0.12 mm, 0.14 mm, 0.15 mm, 0.16 mm, 0.17 mm, 0.18 mm, 0.19 mm, 0.2 mm, 0.21 mm, 0.22 mm, 0.23 mm, 0.24 mm, 0.25 mm, 0.26 mm, 0.27 mm, 0.28 mm, 0.29 mm, 0.3 mm, 0.31 mm, 0.32 mm, 0.33 mm, 0.34 mm, 0.35 mm, 0.36 mm, 0.37 mm, 0.38 mm, 0.39 mm, 0.4 mm, 0.41 mm, 0.42 mm, 0.43 mm, 0.44 mm, 0.45 mm, 0.46 mm, 0.47 mm, 0.48 mm, 0.49 mm, 0.5 mm, or lies within a range consisting of any two of the above values. Optionally, the thickness of the housing body is 0.3 mm to 0.4 mm.

[0194] For example, the thickness of the third housing section 213 is 0.1 mm to 0.5 mm, for example 0.1 mm, 0.12 mm, 0.14 mm, 0.15 mm, 0.16 mm, 0.17 mm, 0.18 mm, 0.19 mm, 0.2 mm, 0.21 mm, 0.22 mm, 0.23 mm, 0.24 mm, 0.25 mm, 0.26 mm, 0.27 mm, 0.28 mm, 0.29 mm, 0.3 mm, 0.31 mm, 0.32 mm, 0.33 mm, 0.34 mm, 0.35 mm, 0.36 mm, 0.37 mm, 0.38 mm, 0.39 mm, 0.4 mm, 0.41 mm, 0.42 mm, 0.43 mm, 0.44 mm, 0.45 mm, 0.46 mm, 0.47 mm, 0.48 mm, 0.49 mm, 0.5 mm, or lies within a range consisting of any two of the above values. Optionally, the thickness of the housing body is 0.3 mm to 0.4 mm. First electrode connection

[0195] In some embodiments, the battery cell 7 further comprises a first electrode terminal 31, and the first electrode terminal 31 is connected to the first electrode tab 111.

[0196] In some embodiments, at least one first electrode connection 31 is provided, optionally several, for example two, three or four.

[0197] As in Fig. As shown in Figure 12, in some embodiments at least one first electrode terminal 31 is arranged on at least one side of the electrode arrangement 10 along the lateral direction Y. This arrangement can shorten the migration path of the electrons and contributes to improving fast charging performance.

[0198] For example, all first electrode connections 31 are arranged on one side of the electrode arrangement 10 along the lateral direction Y.

[0199] In another example, several first electrode terminals 31 are arranged on both sides of the electrode arrangement 10 along the lateral direction Y.

[0200] As in Fig.As shown in Figure 13, in some embodiments at least one first electrode connection 31 is arranged on at least one side of the electrode arrangement 10 along the longitudinal direction Z.

[0201] For example, all first electrode connections 31 are arranged on one side of the electrode arrangement 10 along the longitudinal direction Z.

[0202] In another example, several first electrode terminals 31 are arranged on both sides of the electrode array 10 along the longitudinal direction Z. This arrangement can shorten the migration path of the electrons and contributes to improving fast charging performance.

[0203] By way of example, two first electrode connections 31 are provided, wherein one of the first electrode connections 31 is arranged on one side of the electrode arrangement 10 and the other first electrode connection 31 is arranged on the other side of the electrode arrangement 10. Alternatively, by way of example, four first electrode connections 31 are provided, wherein two of the first electrode connections 31 are arranged on one side of the electrode arrangement 10 and the other two first electrode connections 31 are arranged on both sides of the electrode arrangement 10.

[0204] The first electrode tab 111 and the first electrode terminal 31 are electrically connected, either directly or indirectly; if the first electrode tab 111 and the first electrode terminal 31 are indirectly connected, the battery cell 7 may comprise a first adapter 51, wherein the first adapter 51 is located between the first electrode terminal 31 and the first electrode tab 111 and connects the first electrode terminal 31 and the first electrode tab 111.

[0205] For example, if the first electrode connection 31 is arranged on at least one side of the electrode arrangement 10 along the longitudinal direction Z and the first electrode tab 111 is arranged on at least one side of the first electrode sheet main body 112 along the lateral direction Y, the first adapter 51 is advantageous for connecting the first electrode tab 111 and the first electrode connection 31.

[0206] If the first electrode tab 111 and the first electrode terminal 31 are arranged on different sides of the battery cell 7, the first adapter 51 can comprise a first adapter section 511 and a second adapter section 512, wherein the first adapter section 511 extends along the longitudinal direction Z, the first adapter section 511 is connected to the first electrode tab 111, the second adapter section 512 is connected to the first adapter section 511 and projects along the lateral direction Y from the first adapter section 511 and is connected to the first electrode terminal 31.

[0207] In the case that the first electrode tab 111 and the first electrode terminal 31 are located on the same side of the battery cell 7, the first adapter 51 can only comprise the first adapter section 511.

[0208] In the above embodiments, the first adapter 51 can have a plate-shaped structure and can also have another structure.

[0209] In the above embodiments, the first adapter 51 may comprise a conductive polymer or a conductive metal material, wherein the conductive metal material may comprise copper, aluminum or an alloy containing the above-mentioned metal elements.

[0210] In some embodiments, the battery cell 7 also includes a first conductive element 61, wherein the first conductive element 61 is located between the first adapter 51 and the first electrode tab 111. The arrangement of the first conductive element 61 increases the current-carrying capacity between the first electrode tab 111 and the first adapter 51, which has a positive effect on improving fast-charging performance and reducing heat generation.

[0211] For example, the electrode tab section of the first electrode sheet 11 is arranged on one side of the electrode sheet main body along the width direction Y; the first conductive element 61 is located between the first adapter 51 and the first electrode tab 111 and connects the first adapter 51 and the first electrode tab 111.

[0212] Optionally, several first conductive elements 61 are provided, wherein the first conductive elements 61 and the first electrode tabs 111 are connected one-to-one, and the several first conductive elements 61 are connected to the first adapter 51. This connection method contributes to improving the weight energy density of the battery cell 7.

[0213] As in Fig.As shown in Figure 14, several first electrode tabs 111 are optionally provided on the same side of the first electrode sheet main body 112, and the first conductive element 61 can have a continuous plate-shaped structure and connects the several first electrode tabs 111.

[0214] The first conductive element 61, when the first electrode tab 111 and the first electrode terminal 31 are arranged on opposite sides of the battery cell 7, optionally comprises a first conductive section 611 and a second conductive section 612, wherein the first conductive section 611 extends along the longitudinal direction Z, connects the first electrode tab 111 and the first adapter 51, the second conductive section 612 is connected to the first conductive section 611, and the second conductive section 612 projects from the first conductive section 611 along the lateral direction Y and is connected to the first adapter 51. This structural arrangement is advantageous for increasing the grouping space in the longitudinal direction Z and improving the energy density of the battery device.

[0215] It should be noted that if the battery cell 7 does not include a first adapter 51, the first electrode tab 111 can be connected to the first electrode terminal 31 via the first conductive element 61.

[0216] For example, the first conductive element 61 exhibits electrical conductivity and may comprise a conductive polymer or a conductive metal material, wherein the conductive metal material may include copper, aluminum, or an alloy containing the aforementioned metal elements.

[0217] In some embodiments, the thickness of the first conductive element 61 is 0.5 mm to 2.0 mm, for example 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, 1.0 mm, 1.1 mm, 1.2 mm, 1.3 mm, 1.4 mm, 1.5 mm, 1.6 mm, 1.7 mm, 1.8 mm, 1.9 mm, 2.0 mm, or lies within a range consisting of any two of the above values. If the thickness of the first conductive element 61 is within the above range, the current-carrying capability can be effectively increased and the fast-charging capability improved.

[0218] In the embodiments of the present application, the first electrode connection 31 can be designed as a one-piece structure, which can either be formed in one piece or joined to form a one-piece structure by welding or similar processes, the one-piece structure contributing to reducing resistance and heat generation. Second electrode connection

[0219] In some embodiments, the battery cell further comprises a second electrode terminal 32, and the second electrode terminal 32 is connected to the second electrode tab 121.

[0220] In some embodiments, at least one second electrode connection 32 is provided, optionally several, for example two, three or four.

[0221] In some embodiments, at least one second electrode connection 32 is arranged on at least one side of the electrode arrangement 10 along the lateral direction Y. This arrangement can shorten the migration path of the electrons and contributes to improving fast charging performance.

[0222] For example, all second electrode terminals 32 are arranged on one side of the electrode arrangement 10 along the lateral direction Y. In this case, the first electrode terminal 31 and the second electrode terminal 32 can each be arranged on both sides of the electrode arrangement 10 along the lateral direction Y and do not interfere with each other if they are each independently electrically connected to the electrode tab sections.

[0223] By way of example, two first electrode connections 31 and two second electrode connections 32 are provided, wherein the two first electrode connections 31 are arranged on one side of the electrode arrangement 10 along the width direction Y and the two second electrode connections 32 are arranged on the other side of the electrode arrangement 10 along the width direction Y. Fig.Figure 14 shows a schematic representation in which the first electrode connection 31 and the second electrode connection 32 are arranged on both sides of the electrode arrangement 10 along the width direction Y.

[0224] In another example, several second electrode terminals 32 are arranged on both sides of the electrode assembly 10 along the lateral direction Y. This arrangement can further shorten the electron migration path, which has a positive effect on improving fast charging performance. In this case, the first electrode terminals 31 and the second electrode terminals 32 are arranged on one side of the electrode assembly 10 along the lateral direction Y, and the first electrode terminals 31 and the second electrode terminals 32 are arranged on the other side of the electrode assembly 10 along the lateral direction Y.

[0225] In some embodiments, at least one second electrode connection 32 is arranged on at least one side of the electrode arrangement 10 along the longitudinal direction Z.

[0226] For example, several second electrode terminals 32 are arranged on both sides of the electrode assembly 10 along the longitudinal direction Z. This arrangement can shorten the electron migration path and contributes to improved fast charging performance. In this case, the first electrode terminals 31 and the second electrode terminals 32 are arranged on one side of the electrode assembly 10 along the longitudinal direction Z, and the first electrode terminals 31 and the second electrode terminals 32 are arranged on the other side of the electrode assembly 10 along the longitudinal direction Z.

[0227] For example, two second electrode connections 32 are provided, one of which is located on one side of the electrode arrangement 10 along the longitudinal direction Z, and the other is located on the opposite side of the electrode arrangement 10 along the longitudinal direction Z. Two first electrode connections 31 are also provided, one of which is located on one side of the electrode arrangement 10 and the other on the opposite side. Fig. Figure 14 shows a schematic representation with four electrode connections.

[0228] In another example, all second electrode terminals 32 are arranged on one side of the electrode arrangement 10 along the longitudinal direction Z. In this case, the first electrode terminal 31 and the second electrode terminal 32 can each be arranged on both sides of the electrode arrangement 10 along the longitudinal direction Z and do not interfere with each other if they are each independently electrically connected to the electrode tab sections.

[0229] As in Fig.As shown in Figure 15, a first electrode connection 31 and a second electrode connection 32 are provided by way of example, wherein the first electrode connection 31 and the second electrode connection 32 are located on both sides of the electrode arrangement along the longitudinal direction Z and the first electrode connection 31 and the second electrode connection 32 are arranged offset along the lateral direction Y.In particular, if all second electrode tabs 121 are arranged on the same side of the second electrode sheet main body 122 along the lateral direction Y, and all first electrode tabs 111 are arranged on the same side of the first electrode sheet main body 112 along the lateral direction Y, then the first electrode tabs 111 and the second electrode tabs 121 are each arranged on both sides of the electrode sheet main body along the lateral direction Y, the first electrode terminal 31 is arranged near the first electrode tab 111, and the second electrode terminal 32 is arranged near the second electrode tab 121. This arrangement ensures that the electron transport distance is shorter, which contributes to increasing the fast-charging capability of the battery cell 7.

[0230] The second electrode tab 121 and the second electrode terminal 32 are electrically connected, either directly or indirectly; if the second electrode tab 121 and the second electrode terminal 32 are indirectly connected, the battery cell 7 may include a second adapter, the second adapter being located between the second electrode terminal 32 and the second electrode tab 121 and connecting the second electrode terminal 32 and the second electrode tab 121.

[0231] For example, if the second electrode connection 32 is arranged on at least one side of the electrode arrangement 10 along the longitudinal direction Z and the second electrode tab 121 is arranged on at least one side of the second electrode sheet main body 122 along the lateral direction Y, the second adapter for the connection between the second electrode tab 121 and the second electrode connection 32 is more advantageous.

[0232] If the second electrode tab 121 and the second electrode terminal 32 are arranged on different sides of the battery cell 7, the second adapter can comprise a first connection section and a second connection section, wherein the first connection section extends along the longitudinal direction Z, the first connection section is connected to the second electrode tab 121, the second connection section is connected to the first connection section and projects along the lateral direction Y from the first connection section and is connected to the second electrode terminal 32.

[0233] In the case that the second electrode tab 121 and the second electrode terminal 32 are located on the same side of the battery cell 7, the second adapter can only include the first connection section.

[0234] In the above embodiments, the second adapter can have a plate-shaped structure or another structure.

[0235] In the above embodiments, the second adapter may comprise a conductive polymer or a conductive metal material, wherein the conductive metal material may comprise copper, aluminum or an alloy containing the aforementioned metal elements.

[0236] In some embodiments, the battery cell 7 also includes a second conductive element, the second conductive element being located between the second adapter and the second electrode tab 121. The arrangement of the second conductive element increases the current-carrying capacity between the second electrode tab 121 and the second adapter, which has a positive effect on improving fast-charging performance and reducing heat generation.

[0237] For example, the electrode tab section of the second electrode sheet 12 is arranged on one side of the electrode sheet main body along the width direction Y; the second conductive element is located between the second adapter and the second electrode tab 121 and connects the second adapter and the second electrode tab 121.

[0238] Optionally, several second electrode tabs 121 are provided on the same side of the second electrode sheet main body 122, and the second conductive element can have a continuous plate-shaped structure and connect the several second electrode tabs 121; or several second conductive elements are provided, wherein the second conductive elements and the second electrode tabs 121 are connected one-to-one, and the several second conductive elements are connected to the second adapter. This connection method contributes to improving the weight energy density of the battery cell 7.

[0239] If the second electrode tab 121 and the second electrode terminal 32 are arranged on opposite sides of the battery cell 7, the second conductive section optionally comprises a third conductive section and a fourth conductive section. The third conductive section extends along the longitudinal direction Z, connects the electrode tab section of the second electrode sheet 12 and the second adapter, and the fourth conductive section is connected to the third conductive section and projects from the third conductive section along the lateral direction Y, connecting to the second adapter. This structural arrangement is advantageous for increasing the grouping space in the longitudinal direction Z and improving the energy density of the battery device.

[0240] For example, the second conductive element exhibits electrical conductivity and may comprise a conductive polymer or a conductive metal material, the conductive metal material being copper, aluminum, or an alloy containing the aforementioned metal elements.

[0241] It should be noted that if the battery cell 7 does not include a second adapter, the second electrode tab 121 can be connected to the second electrode terminal 32 via the second conductive element. Positive electrode sheet

[0242] For the sake of clarity in the present application, the electrode sheet main body of the positive electrode sheet corresponds to the positive electrode sheet main body, the electrode tab section corresponds to the positive electrode tab, the active material layer corresponds to the positive electrode active material layer containing the positive electrode active material, wherein the positive electrode sheet main body comprises a positive electrode current collection section and a positive electrode active material layer arranged on at least one side of the positive electrode current collection section.

[0243] The positive electrode sheet comprises a positive electrode current collector section and a positive electrode active material layer, which is arranged on at least one surface of the positive electrode current collector section and comprises a positive electrode active material. For example, the positive electrode current collector section has two surfaces that are opposite each other along its thickness direction, and the positive electrode active material layer is arranged on one or both of the two opposite surfaces of the positive electrode current collector section.

[0244] The upper charging voltage and the discharge cut-off voltage of the battery cell differ depending on the positive electrode active material. For example, if the phosphate material comprises lithium iron phosphate, the upper charging voltage can be 3.65 V and the discharge cut-off voltage 2.0 V, or the upper charging voltage can be 3.8 V and the discharge cut-off voltage 2.0 V. If the phosphate material also comprises, for example, lithium manganese iron phosphate, the upper charging voltage can be 4.3 V and the discharge cut-off voltage 2.0 V. The state of the battery cell is explained below using the example of an upper charging voltage of 3.65 V and a discharge cut-off voltage of 2.0 V: In the embodiments of the present application, the state of charge (SOC) of 100% and the state of charge (SOC) of the battery cell are defined as follows:

[0245] The battery cell is charged at a constant rate of 0.33C up to the upper charging limit voltage and then further charged at a constant voltage down to 0.05C, which corresponds to a state of 100% SOC (State of Charge) of the battery cell. The battery cell is then discharged at a constant rate of 0.33C down to the final voltage, which corresponds to a state of 0% SOC of the battery cell.

[0246] In some embodiments, the compaction density of the positive electrode active material layer is 2.30 g / cm³. 3 up to 2.70 g / cm³ 3 , optional 2.40 g / cm² 3 up to 2.55 g / cm³ 3 When the battery cell is at a state of charge (SOC) of 0%, the density of the positive electrode active material layer is, for example, 2.30 g / cm³. 3 , 2.32 g / cm³ 3 , 2.35 g / cm³ 3 , 2.38 g / cm³ 3 , 2.40 g / cm³ 3 , 2.42 g / cm³3 , 2.45 g / cm³ 3 , 2.48 g / cm³ 3 , 2.50 g / cm³ 3 , 2.52 g / cm³ 3 , 2.55 g / cm³ 3 , 2.56 g / cm³ 3 , 2.57 g / cm³ 3 , 2.58 g / cm³ 3 , 2.60 g / cm³ 3 , 2.62 g / cm³ 3 , 2.65 g / cm³ 3 , 2.68 g / cm³ 3 , 2.70 g / cm³ 3 or lies within a range consisting of any two of the values ​​mentioned above.

[0247] If the density of the positive electrode active material layer is within the range mentioned above, this is advantageous for increasing the energy density of the battery cell. Because the positive electrode active material is packed relatively densely in the positive electrode active material layer, and the contact resistance between the particles is low, the resistance of the electrode sheet can be further reduced, thereby reducing heat generation during fast charging, mitigating the problem of increased side reactions on the negative electrode side due to heat build-up, and improving the cycle performance of the battery cell.

[0248] In some embodiments, the one-sided coating weight of the positive electrode active material layer is 250 mg / 1540.25 mm². 2 up to 330 mg / 1540.25 mm 2 , optional 275 mg / 1540.25 mm 2 up to 300 mg / 1540.25 mm 2For example, the one-sided coating weight of the positive electrode active material layer is 250 mg / 1540.25 mm². 2 , 260 mg / 1540.25 mm 2 , 270 mg / 1540.25 mm 2 , 280 mg / 1540.25 mm 2 , 290 mg / 1540.25 mm 2 , 300 mg / 1540.25 mm 2 , 310 mg / 1540.25 mm 2 , 320 mg / 1540.25 mm 2 , 330 mg / 1540.25 mm 2 or lies within a range consisting of any two of the values ​​mentioned above.

[0249] If the one-sided coating weight of the positive electrode active material layer is within the above range, the amount of heat generated per unit area of ​​the positive electrode sheet is not too large, thus mitigating the problem of increased side reactions on the negative electrode side due to heat build-up, improving the cycle performance of the battery cell and increasing the energy density of the battery cell.

[0250] In the embodiments of the present application, the density of the positive electrode active material layer in the battery cell at a state of charge (SOC) of 0% has the meaning known in the art. The positive electrode sheet is thus removed from the battery cell at a state of charge (SOC) of 0%, and the density of the positive electrode active material layer is measured. For example, the positive electrode sheet coated on one side (in the case of a double-sided electrode sheet, the positive electrode active material layer can first be wiped off on one side) is taken, then punched into small discs with an area of ​​S1 and weighed, and its weight is recorded as M1. Subsequently, its thickness H1 is measured.The positive electrode active material layer of the above-mentioned weighed positive electrode sheet is then wiped clean. The positive electrode current collector section is weighed and its weight is recorded as M0, and its thickness H0 is measured. The one-sided coating weight of the positive electrode active material layer = (the weight M1 of the positive electrode sheet - the weight M0 of the positive electrode current collector section) / S1, the thickness of the positive electrode active material layer = the thickness H1 of the positive electrode sheet - the thickness H0 of the positive electrode current collector section, the compaction density of the positive electrode active material layer = the one-sided coating weight of the positive electrode active material layer / the thickness of the positive electrode active material layer.

[0251] In some embodiments, the positive electrode active material comprises a lithium-containing phosphate with an olivine structure. In other embodiments, the positive electrode active material may also comprise a lithium-containing transition metal oxide. Examples of the lithium-containing transition metal oxide may include, but are not limited to, at least one of the following: lithium cobalt oxide, lithium nickel oxide, lithium manganese oxide, lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, lithium nickel cobalt manganese oxide, lithium nickel cobalt aluminum oxide, and their respective modified compounds.

[0252] In the embodiments of the present application, the lithium-containing phosphate with an olivine structure can consist of phosphate particles or of a material obtained by coating and modifying the phosphate particles. For example, the lithium-containing phosphate with an olivine structure comprises phosphate particles and a coating layer, wherein the surface of the phosphate particles is coated with the coating layer and the coating layer includes, for example, elements such as carbon, which improves the conductivity of the phosphate particles, reduces the powder resistance of the material, promotes the migration rate of lithium ions, improves the fast-charging capability of the battery, and reduces the amount of heat generated by the battery cell.

[0253] In some embodiments, the phosphate particles comprise a compound with the general formula of Li x1 A y1 Me a M b P 1-c X c Y z, where 0.5 ≤ x1 ≤ 1.3, 0 ≤ y1 ≤ 1.3 and 0.9 ≤ x1 + y1 ≤ 1.3, 0.9 ≤ a ≤ 1.5, 0 ≤ b ≤ 0.5 and 0.9 ≤ a + b ≤ 1.5, 0 ≤ c ≤ 0.5, 3 ≤ z ≤ 5, A comprises one or more of Na, K and Mg, Me comprises one or more of Mn, Fe, Co and Ni, M comprises one or more of B, Mg, Al, Si, P, S, Ca, Sc, Ti, V, Cr, Cu, Zn, Sr, Y, Zr, Nb, Mo, Cd, Sn, Sb, Te, Ba, Ta, W, Yb, La and Ce, X The phosphate particles comprise one or more of Cl, C, and N, and the phosphate group comprises one or more of O and F. These particles exhibit excellent cycle stability, which positively impacts the cycle performance of the battery cell.

[0254] Examples of phosphate particles include one or more LiFePO4, LiMnPO4, LiNiPO4, and LiCoPO4. During the charging and discharging process of the battery cell, deintercalation and intercalation, as well as the consumption of active ions such as Li, occur, and the molar content of Li varies depending on the state of discharge of the battery cell. When listing positive electrode active materials such as LiFePO4, LiMnPO4, LiNiPO4, LiCoPO4, etc., the molar content of Li refers to the initial state of the material, i.e., the state before it is added. The positive electrode active material is used in the battery system. After the charge-discharge cycle, the molar content of Li may change. When listing positive electrode active materials such as LiFePO4, LiMnPO4, LiNiPO4, LiCoPO4, etc., in the embodiments of the present application, the molar content of oxygen (O) is only a theoretical value.The release of oxygen from the lattice leads to a change in the molar content of oxygen (O), which is why the molar content of oxygen (O) varies in practice. The situations described above all fall within the scope of protection of this application.

[0255] In the embodiments of the present application, the element content in the positive electrode active material has a meaning known in the art and can be determined using devices and methods known in the art. For example, it is measured by inductively coupled plasma atomic emission spectroscopy (ICP-OES, instrument model: Thermo ICAP7400) with reference to EPA 6010D-2014. After the battery cell is discharged to a state of charge (SOC) of 0%, the positive electrode sheet is removed, cleaned with dimethyl carbonate (DMC), and dried. It is then calcined at a high temperature to remove impurities. Next, 0.4 g of positive electrode active material is weighed out and mixed with 10 mL (50% concentration) of aqua regia. It is then placed on a plate at 180 °C for 30 minutes.After digestion on the plate, the volume is made up to 100 mL and the quantitative test is carried out using the standard curve method.

[0256] In some embodiments, the positive electrode active material layer also includes a positive electrode additive, which may further comprise a lithium element. During the charging process of the battery cell, lithium ions can be released to compensate for lithium loss and thereby improve the capacity characteristics and cycle life of the battery cell.

[0257] In some embodiments, the average longest diameter of the positive electrode additive is 2 µm to 5 µm, for example, 2 µm, 3 µm, 3.5 µm, 4 µm, 4.5 µm, 5 µm, or lies within a range consisting of any two values. Using a positive electrode additive with the particle size mentioned above can effectively improve the stability of the positive electrode additive while simultaneously compensating for lithium loss.

[0258] In the embodiments of the present application, the positive electrode sheet is cut along its thickness direction to expose the longitudinal section of the positive electrode active material layer; the longitudinal section of the positive electrode active material layer is examined by scanning electron microscopy (SEM) to determine the longest diameter of the particles of the positive electrode additive and the longest diameter of the lithium-containing phosphate. For example, the “longest diameter” of a particle refers to the longest straight line passing through the center of the particle and extending to the outer circumference of the particle.

[0259] In the cross-section of the positive electrode active material layer along its own thickness direction, the longest diameters of several, for example 10, lithium-containing iron oxides are counted and their average value is calculated as the average longest diameter.

[0260] In some embodiments, the mass fraction of the positive electrode additive, based on the total mass of the positive electrode active material layer, is 0.2% to 2%, for example, 0.2%, 0.4%, 0.6%, 0.8%, 1.0%, 1.2%, 1.4%, 1.6%, 1.8%, 2.0%, or lies within a range consisting of any two values. Using a positive electrode additive with the above mass range effectively compensates for lithium loss.

[0261] In some embodiments, the positive electrode active material layer optionally further comprises a conductive element of the positive electrode. The embodiments of the present application are not subject to any particular restrictions regarding the type of conductive element of the positive electrode. By way of example, the conductive element of the positive electrode comprises at least one of superconducting carbon, conductive graphite, carbon black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers. In some embodiments, the mass fraction of the conductive element of the positive electrode is ≤ 5%, based on the mass of the positive electrode active material layer.

[0262] In some embodiments, the positive electrode active material layer optionally further comprises a positive electrode binder. The embodiments of the present application are not subject to any particular restrictions regarding the type of positive electrode binder. By way of example, the positive electrode binder may comprise at least one of the following: polyvinylidene fluoride, polytetrafluoroethylene, a vinylidene fluoride-tetrafluoroethylene-propylene terpolymer, a vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene terpolymer, a tetrafluoroethylene-hexafluoropropylene copolymer, polyacrylic acid, and a fluorine-containing acrylate resin. In some embodiments, the mass fraction of the positive electrode binder is ≤ 5%, based on the mass of the positive electrode active material layer.

[0263] In some embodiments, the positive electrode current collector section can be a metal foil or a composite current collector section. For example, the metal foil can be made of at least one material: aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver, or silver alloy. The composite current collector section can comprise a polymer base layer and a metal layer formed on at least one surface of the polymer base layer. For example, the metal material of the metal layer can be aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver, or silver alloy. For example, the polymer base layer can be polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), or polyethylene (PE).

[0264] In some embodiments, the ratio of the thickness of the one-sided positive electrode active material layer to the thickness of the positive electrode current collection section is 3 to 10, for example 3, 4, 5, 6, 7, 8, 9, 10, or lies in a range consisting of any two of the above values. Optionally, the ratio of the thickness of the one-sided positive electrode active material layer to the thickness of the positive electrode current collection section is 4 to 8.

[0265] If the ratio of the thickness of the one-sided positive electrode active material layer to the thickness of the positive electrode current collection section is within the above range, the fast charging capability and the energy density of the battery cell can be increased.

[0266] In some embodiments, the thickness of the positive electrode current collector section is 12 µm to 16 µm, optionally 13 µm to 15 µm. For example, the thickness of the positive electrode current collector section is 12 µm, 12.5 µm, 13 µm, 13.5 µm, 14 µm, 14.5 µm, 15 µm, 15.5 µm, 16 µm, or lies in a range consisting of any two of the above values.

[0267] If the thickness of the positive electrode current collection section is within the range mentioned above, the positive electrode current collection section exhibits relatively excellent current conductivity and allows for a higher energy density of the battery cell.

[0268] In the embodiments of the present application, the thicknesses of the positive electrode active material layer and the positive electrode current collection section have meanings known in the art and can be measured using devices and methods known in the art, for example by measuring the thickness of the positive electrode sheet with a high-precision micrometer, removing the film layer from the surface of the positive electrode current collection section and measuring the thickness of the positive electrode current collection section with the high-precision micrometer, wherein, in the case of single-sided coating of the positive electrode active material layer, its thickness corresponds to the difference between the thickness of the positive electrode sheet and that of the positive electrode current collection section, while in the case of double-sided coating, the thickness of the positive electrode active material layer corresponds to half of this difference.

[0269] The positive electrode active material layer is typically formed by applying a positive electrode paste to the positive electrode current collector section, followed by drying and cold pressing. The positive electrode paste is generally formed by dispersing and uniformly stirring the positive electrode active material, an optional conductive agent, an optional binder, and any other components in a solvent. The solvent may be, but is not limited to, N-methyl-2-pyrrolidone (NMP).

[0270] The positive electrode sheet does not exclude further additional functional layers besides the positive electrode active material layer. For example, in some embodiments, the positive electrode sheet according to the embodiments of the present application also comprises a conductive layer of the positive electrode, which is enclosed between the positive electrode current collection section and the positive electrode active material layer and is arranged on the surface of the positive electrode current collection section. In some other embodiments, the positive electrode sheet according to the embodiments of the present application further comprises a protective layer that covers the surface of the positive electrode active material layer. Negative electrode sheet

[0271] For the sake of clarity of the present application, the electrode sheet main body of the negative electrode sheet corresponds to the electrode sheet main body of the negative electrode, the electrode tab section corresponds to the negative electrode tab, and the active material layer corresponds to a negative electrode active material layer containing the negative electrode active material, wherein the negative electrode sheet main body comprises a negative electrode current collection section and a negative electrode active material layer arranged on at least one side of the negative electrode current collection section.

[0272] The negative electrode sheet comprises a negative electrode current collector section and a negative electrode active material layer, which is arranged on at least one surface of the negative electrode current collector section and comprises a negative electrode active material. For example, the negative electrode current collector section has two surfaces that are opposite each other along its thickness direction, and the negative electrode active material layer is arranged on one or both of the two opposite surfaces of the negative electrode current collector section.

[0273] In some embodiments, the compaction density of the negative electrode active material layer is 1.30 g / cm³. 3 up to 1.65 g / cm³ 3 , optional 1.35 g / cm² 3 up to 1.50 g / cm³ 3When the battery cell is at a state of charge (SOC) of 0%, the density of the negative electrode active material layer is, for example, 1.3 g / cm³. 3 , 1.32 g / cm³ 3 , 1.35 g / cm³ 3 , 1.40 g / cm³ 3 , 1.45 g / cm³ 3 , 1.50 g / cm² 3 , 1.55 g / cm³ 3 , 1.60 g / cm³ 3 , 1.65 g / cm³ 3 or lies within a range consisting of any two of the values ​​mentioned above.

[0274] If the density of the negative electrode active material layer is within the range mentioned above, this is advantageous for increasing the energy density of the battery cell. Because the negative electrode active material is packed relatively densely in the negative electrode active material layer, and the contact resistance between the particles is low, the resistance of the electrode sheet can be further reduced, thereby decreasing heat generation, mitigating the problem of increased side reactions on the negative electrode side due to heat build-up, and improving the cycle performance of the battery cell.

[0275] In the embodiments of the present application, the density of the negative electrode active material layer when the battery cell is at a state of charge (SOC) of 0% has a meaning known in the art and can be determined using devices and methods known in the art. The detection method, for example, is the same as the test method for the density of the positive electrode active material layer.

[0276] In some embodiments, the one-sided coating weight of the negative electrode active material layer is 120 mg / 1540.25 mm². 2 up to 180 mg / 1540.25 mm 2 , optional 125 mg / 1540.25 mm 2 up to 150 mg / 1540.25 mm 2 For example, the one-sided coating weight of the negative electrode active material layer is 120 mg / 1540.25 mm². 2 , 122 mg / 1540.25 mm 2 , 125 mg / 1540.25 mm 2 , 128 mg / 1540.25 mm 2, 130 mg / 1540.25 mm 2 , 132 mg / 1540.25 mm 2 , 135 mg / 1540.25 mm 2 , 137 mg / 1540.25 mm 2 , 140 mg / 1540.25 mm 2 , 145 mg / 1540.25 mm 2 , 150 mg / 1540.25 mm 2 , 155 mg / 1540.25 mm 2 , 160 mg / 1540.25 mm 2 , 165 mg / 1540.25 mm 2 , 170 mg / 1540.25 mm 2 , 175 mg / 1540.25 mm 2 , 180 mg / 1540.25 mm 2 or lies within a range consisting of any two of the values ​​mentioned above.

[0277] If the one-sided coating weight of the negative electrode active material layer is within the above range, the amount of heat generated per unit area of ​​the negative electrode sheet is not too large, thus mitigating the problem of increased side reactions on the negative electrode side due to heat build-up, improving the cycle performance of the battery cell and simultaneously increasing the energy density of the battery cell.

[0278] In the embodiments of the present application, the one-sided coating weight of the negative electrode active material layer has the meaning known in the art and can be determined using devices and methods known in the art, and the detection method is the same as the above test method for the one-sided coating weight of the film layer.

[0279] In some embodiments, the negative electrode active material comprises a carbon-based material. This carbon-based material exhibits high cycle stability, thereby improving the cycle performance of the battery cell. The positive electrode active material of the present application consists mainly of a lithium-containing phosphate system with an olivine structure, while the negative electrode active material consists mainly of a carbon-based material system. The two are used in combination, resulting in a relatively excellent cycle performance of the battery cell.

[0280] Optionally, the carbon-based material includes synthetic graphite. This synthetic graphite exhibits excellent conductivity, which reduces heat generation from the negative electrode sheet and the battery cell, thereby improving the battery cell's fast-charging performance.

[0281] In some embodiments, the carbon-based material may further comprise natural graphite. In particular, the carbon-based material may comprise synthetic graphite, or the carbon-based material may comprise synthetic graphite and natural graphite. Natural graphite exhibits relatively good conductivity, which helps to further reduce heat generation and improve the performance and cycle life of battery cells.

[0282] In some embodiments, the negative electrode active material can, in addition to the carbon-based material mentioned above and optionally the silicon-based material, comprise at least one tin-based material and one lithium titanate. The tin-based material can comprise at least one elemental tin, tin oxide, and tin alloy material. Optionally, the silicon-based material can comprise at least one elemental silicon, silicon oxide, silicon-carbon composite, silicon-nitrogen composite, and silicon alloy material.

[0283] The qualitative and quantitative determination of the individual substances or elements in the present application can be carried out using suitable equipment and methods known to those skilled in the art. The relevant methods of determination may refer to national and international testing standards as well as national and international company standards. Those skilled in the art may also adjust certain test steps / equipment parameters with regard to test accuracy in order to obtain more precise test results. A single method may be used for the qualitative or quantitative determination, or a combination of several methods may be used.

[0284] For example, the present application, in combination with the general rule for X-ray diffraction analysis JIS / K0131-1996, can perform an X-ray powder diffraction test and a qualitative analysis of the negative electrode sheet or the negative electrode active material.

[0285] Artificial and natural graphite can be distinguished using SEM cross-sectional images obtained with a scanning electron microscope (SEM). The SEM cross-sectional image of natural graphite shows gaps between the scaly structures, while the SEM cross-sectional image of artificial graphite is dense and shows no obvious gaps. They can also be distinguished using their XRD spectra obtained by X-ray diffraction. The XRD spectrum of natural graphite shows a distinct 2H phase and a 3R phase, while the XRD spectrum of artificial graphite shows only the 2H phase.

[0286] In the embodiments of the present application, the negative electrode active material layer comprises at least one film layer, wherein either a single film layer or at least two film layers may be present. Optionally, the negative electrode active material layer comprises at least two film layers.

[0287] In the case where the negative electrode active material layer comprises a single-layer film, the negative electrode active material in the negative electrode active material layer comprises a carbon-based material. In the case where a single-layer film is present, the volume-averaged particle size Dv50 of the carbon-based material is 8 µm to 13 µm, optionally 9.5 µm to 11.5 µm. For example, the volume-averaged particle size Dv50 of the carbon-based material is 8 µm, 8.5 µm, 8.8 µm, 9 µm, 9.2 µm, 9.5 µm, 9.8 µm, 10 µm, 10.2 µm, 10.5 µm, 10.8 µm, 11 µm, 11.2 µm, 11.5 µm, 11.8 µm, 12 µm, 12.2 µm, 12.5 µm, 12.8 µm, 13 µm or lies in a range consisting of any two of the above values.

[0288] In cases where the negative electrode active material layer comprises at least two film layers, the negative electrode active material in the negative electrode active material layer comprises a carbon-based material. The negative electrode active material layer can comprise two film layers, three film layers, four film layers, or even more film layers.

[0289] In some embodiments, the negative electrode active material layer comprises a first negative electrode film layer and a second negative electrode film layer, wherein the first negative electrode film layer is arranged on the surface of the negative electrode current collection section, the carbon-based material of the first negative electrode film layer comprises artificial graphite, the second negative electrode film layer is connected to a side of the first negative electrode film layer facing away from the negative electrode current collection section, and the carbon-based material of the second negative electrode film layer comprises artificial graphite, wherein the artificial graphite of the first electrode film layer and the artificial graphite of the second negative electrode film layer may be the same or different.If the artificial graphite of the first negative electrode film layer and the artificial graphite of the second negative electrode film layer are different, they may have different particle sizes or different degrees of graphitization.

[0290] The interface between the first negative electrode film layer and the second negative electrode film layer is regular or irregular, optionally irregular.

[0291] The negative electrode active material layer comprises at least two film layers. This multilayer coating contributes to improving the fast-charging performance of the battery cell. In particular, if there is a difference between the first and second negative electrode film layers, the pore size difference of the negative electrode active material layer can be increased, the toriosity of lithium-ion transport can be reduced, and the fast-charging performance of the battery cell can be improved.

[0292] In some embodiments, the volume-averaged particle size Dv50 of the carbon-based material of the first negative electrode film layer is greater than or equal to the volume-averaged particle size Dv50 of the carbon-based material of the second negative electrode film layer. Optionally, the volume-averaged particle size Dv50 of the carbon-based material of the first negative electrode film layer is larger than the volume-averaged particle size Dv50 of the carbon-based material of the second negative electrode film layer, which contributes to increasing the kinetic performance of the negative electrode active material layer.

[0293] The particle size of the first and second negative electrode film layers differs, which can improve the fast-charging performance of the battery cell. In particular, during fast charging, the overpotential of the second negative electrode film layer is typically higher, and the bottleneck during fast charging lies mainly in the second negative electrode film layer. In the embodiments of the present application, the particle size of the second negative electrode film layer is relatively small, which shortens the solid-phase transport path of the lithium ions, improves the fast-charging performance, and reduces the problem of lithium plating on the surface of the negative electrode sheet.

[0294] Optionally, the carbon-based material of the first negative electrode film layer is available in granular form and its volume-averaged particle size Dv50 is 9.0 µm to 18.5 µm and optionally 9.0 µm to 14.6 µm. For example, the volume-averaged particle size of the carbon-based material of the second negative electrode film layer is 9.0 µm, 10 µm, 10.5 µm, 11 µm, 11.5 µm, 12 µm, 12.5 µm, 13 µm, 13.5 µm, 14 µm, 14.5 µm, 14.6 µm, 15 µm, 15.5 µm, 16 µm, 16.5 µm, 17 µm, 17.5 µm, 18 µm, 18.5 µm, or lies within a range consisting of any two of the above values. If the first negative electrode film layer comprises a carbon-based material, the volume-averaged particle size Dv50 of the carbon-based material of the first negative electrode film layer is 9.0 µm to 18.5 µm and optionally 9.0 µm to 14.6 µm.

[0295] If the volume-averaged particle size Dv50 of the carbon-based material of the first negative electrode film layer is within the range mentioned above, the solid-phase transport path of the lithium ions can be shortened and the fast charging performance improved, while the material does not agglomerate as easily during the manufacturing process, which can improve the stability of the material.

[0296] Optionally, the carbon-based material of the second negative electrode film layer is in granular form and its volume-averaged particle size Dv50 is 7.8 µm to 14.3 µm and optionally 7.8 µm to 11.3 µm. For example, the volume-averaged particle size Dv50 of the carbon-based material is 7.8 µm, 8.0 µm, 8.2 µm, 8.5 µm, 8.8 µm, 9 µm, 9.2 µm, 9.5 µm, 9.8 µm, 10 µm, 10.2 µm, 10.5 µm, 10.8 µm, 11 µm, 11.3 µm, 11.2 µm, 11.5 µm, 11.8 µm, 12 µm, 12.2 µm, 12.5 µm, 12.8 µm, 13 µm, 13.2 µm. 13.5 µm, 13.8 µm, 14 µm, 14.1 µm, 14.3 µm, or lies within a range consisting of any two of the above values. If the second negative electrode film layer comprises a carbon-based material, the volume-averaged particle size Dv50 of the carbon-based material of the second negative electrode film layer is 7.8 µm to 14.3 µm, and optionally 7.8 µm to 11.3 µm.

[0297] If the volume-averaged particle size Dv50 of the carbon-based material of the second negative electrode film layer is within the range mentioned above, the solid-phase transport path of the lithium ions can be shortened and the fast charging performance improved.

[0298] If the volume-averaged particle size Dv50 of the carbon-based material of the second negative electrode film layer is within the aforementioned range, the solid-phase transport path of the lithium ions can be shortened and the fast-charging performance improved. Furthermore, the material does not agglomerate as easily during the manufacturing process, which can improve the material's stability. Additionally, combining the negative electrode active material in the second negative electrode film layer and the negative electrode active material in the first negative electrode film layer within the aforementioned volume-averaged particle size range is advantageous for creating a gradient pore difference between the second and first negative electrode film layers, reducing the tortuosity of lithium ion transport and improving the fast-charging performance of the battery cell.

[0299] In the embodiments of the present application, the volume-averaged particle size Dv50 of the negative electrode active material has a meaning known in the art and can be determined using devices and methods known in the art. For example, the negative electrode active material is used as a sample and the Dv50 of the particles, etc., are measured with a Mastersizer 2000E laser particle size analyzer in accordance with test standard GB / T 19077-2016.

[0300] Optionally, the carbon-based material of the first negative electrode film layer also includes natural graphite.

[0301] For example, the carbon-based material of the first negative electrode film layer comprises at least one of artificial graphite and natural graphite, and the carbon-based material of the second negative electrode film layer comprises artificial graphite.

[0302] In some other embodiments, the volume-averaged particle size Dv50 of the carbon-based material of the second negative electrode film layer is larger than the volume-averaged particle size Dv50 of the carbon-based material of the first negative electrode film layer. Furthermore, optionally, the volume-averaged particle size Dv50 of the carbon-based material of the second negative electrode film layer is larger than the volume-averaged particle size Dv50 of the carbon-based material of the first negative electrode film layer, which contributes to improving the compaction density of the negative electrode active material layer.

[0303] The difference in particle size between the first negative electrode film layer and the second negative electrode film layer can improve the fast charging performance of the battery cell.

[0304] For example, the carbon-based material of the second negative electrode film layer comprises at least one of artificial graphite and natural graphite, and the carbon-based material of the first negative electrode film layer comprises artificial graphite.

[0305] In some embodiments, the negative electrode active material layer optionally further comprises a conductive element of the negative electrode. The embodiments of the present application do not specifically restrict the type of conductive element of the negative electrode. By way of example, the conductive element of the negative electrode may comprise at least one of superconducting carbon, conductive graphite, carbon black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers. In some embodiments, the mass fraction of the conductive element of the negative electrode is ≤ 5%, based on the total weight of the negative electrode active material layer.

[0306] In some embodiments, the negative electrode active material layer optionally further comprises a negative electrode binder. In some embodiments, the mass fraction of the negative electrode binder is ≤ 5%, based on the total weight of the negative electrode active material layer.

[0307] In some embodiments, the negative electrode active material layer optionally comprises further excipients. For example, these excipients may include a thickening agent, a dispersing agent, and the like, such as sodium carboxymethylcellulose (CMC-Na), PTC thermistor material, and the like. In some embodiments, the mass fraction of the excipients is less than 2%, based on the total weight of the negative electrode active material layer.

[0308] In some embodiments, the negative electrode current collector section can be a metal foil or a composite current collector section. For example, the metal foil can be made of at least one material: copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver, or silver alloy. The composite current collector section can comprise a polymer base layer and a metal layer formed on at least one surface of the polymer base layer. For example, the metal material in the metal layer can be copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver, or silver alloy. For example, the polymer base layer can be polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), or polyethylene (PE).

[0309] In some embodiments, the ratio of the thickness of the one-sided negative electrode active material layer to the thickness of the negative electrode current collection section is 8 to 14, for example 8, 9, 10, 11, 12, 13, 14, or lies in a range consisting of any two of the above values. Optionally, the ratio of the thickness of the one-sided negative electrode active material layer to the thickness of the negative electrode current collection section is 10 to 12.

[0310] If the ratio of the thickness of the one-sided negative electrode active material layer to the thickness of the negative electrode current collection section is within the above range, the fast charging capability and the energy density of the battery cell can be increased.

[0311] In some embodiments, the thickness of the negative electrode current collector section is 5 µm to 10 µm, optionally 6 µm to 8 µm. For example, the thickness of the negative electrode current collector section is 5 µm, 5.5 µm, 6 µm, 6.5 µm, 7 µm, 7.5 µm, 8 µm, 8.5 µm, 9 µm, 9.5 µm, 10 µm, or lies in a range consisting of any two of the above values.

[0312] If the thickness of the negative electrode current collection section is within the range mentioned above, the negative electrode current collection section exhibits relatively excellent current conductivity and allows for a higher energy density of the battery cell.

[0313] In the embodiments of the present application, the thickness of the negative electrode current collection section has a meaning known in the art and can be determined using devices and methods known in the art, for example by using a solvent to wash off the film layer on the surface of the negative electrode current collection section and by using a high-precision micrometer to measure the thickness of the negative electrode current collection section.

[0314] The negative electrode active material layer is typically formed by applying a negative electrode paste to the negative electrode current collector section, followed by drying and cold pressing. The negative electrode paste is usually formed by dispersing and uniformly stirring the negative electrode active material, an optional conductive agent, an optional binder, and other optional excipients in a solvent. The solvent may be, but is not limited to, N-methyl-2-pyrrolidone (NMP) or deionized water.

[0315] The negative electrode sheet does not exclude further additional functional layers besides the negative electrode active material layer. For example, in some embodiments, the negative electrode sheet according to the embodiments of the present application also comprises a conductive layer of the negative electrode, which is enclosed between the negative electrode current collection section and the negative electrode active material layer and is arranged on the surface of the negative electrode current collection section. In some other embodiments, the negative electrode sheet according to the embodiments of the present application also comprises a protective layer that covers the surface of the negative electrode active material layer. separator

[0316] In some embodiments, the electrode arrangement also includes a separator, wherein the separator is arranged between the positive electrode sheet and the negative electrode sheet.

[0317] In some embodiments, the separator is formed as a film. The present application does not impose any specific restrictions on the type of separator, and any known separator with good chemical and mechanical stability and a porous structure can be used.

[0318] For example, the main material of the separator can be selected from at least one of the following: glass fiber, nonwoven fabric, polyethylene, polypropylene, polyvinylidene fluoride, and ceramic. The separator can be a single-layer film or a multi-layer composite film, without any particular restriction. If the separator is a multi-layer composite film, the materials of each layer can be the same or different, without any particular restriction. The separator can be a separate component located between the positive and negative electrodes, or it can be attached to the surface of the positive and negative electrodes. The surface of the separator can also be coated with an inorganic particle coating, an organic particle coating, or an organic / inorganic composite coating.

[0319] In some embodiments, the separator is designed as a solid electrolyte. The solid electrolyte is arranged between the positive and negative electrodes and performs the functions of ion transport and insulation of the positive and negative electrodes.

[0320] In some embodiments, the volume energy density of the battery cell is between 350 Wh / L and 450 Wh / L. For example, the volume energy density of the battery cell is 350 Wh / L, 375 Wh / L, 380 Wh / L, 390 Wh / L, 400 Wh / L, 410 Wh / L, 420 Wh / L, 430 Wh / L, 450 Wh / L, or lies within a range consisting of any two of the above values. The volume energy density of the battery cell is higher.

[0321] In the embodiments of the present application, the volume energy density of the battery cell has a meaning known in the art and can be determined using devices and methods known in the art. For example, with an upper charging limit voltage of the battery of 3.65 V and a discharge cut-off voltage of the battery of 2.0 V, the following is explained:

[0322] The battery cell is charged at 25 °C with a constant current of 0.33 C to 3.65 V, then charged with a constant voltage to 0.05 C, and finally discharged with a constant current of 0.33 C to 2.0 V. The discharge capacity A0 is recorded at this point in Ah. The length, width, and height of the battery cell are measured using calipers (usually based on the battery casing size, excluding the height of the electrode terminals and the insulating film outside the casing). The volume V0 of each battery is calculated in L. The volumetric energy density of the battery cell VED = (A0 × discharge platform voltage) / V0 in Wh / L. Example of implementation

[0323] The following exemplary embodiments describe in more detail the content disclosed in the embodiments of the present application. These exemplary embodiments serve only as an illustration, since various modifications and changes within the scope of the content disclosed in the embodiments of the present application are obvious to the person skilled in the art. Unless otherwise stated, all proportions, percentages, and ratios given in the following exemplary embodiments refer to mass. All reagents used in the exemplary embodiments are commercially available or are synthesized by conventional methods and can be used directly without further treatment. The instruments used in the exemplary embodiments are commercially available. Example 11. Production of the positive electrode sheet

[0324] The positive electrode sheet comprised a positive electrode tab, a positive electrode current collection section, and positive electrode active material layers arranged on both sides of the positive electrode current collection section, the positive electrode current collection section being a 13 µm thick aluminum foil.

[0325] The positive electrode active material layer comprised a lithium-containing phosphate, a lithium ferrite positive electrode additive, a polyvinylidene fluoride (PVDF) binder, and a carbon black conductive agent in a mass ratio of 96:1:2:1. The positive electrode active material layer was a film formed by uniformly applying the positive electrode paste (solvent: N-methyl-2-pyrrolidone, NMP) to both sides of the positive electrode current collector section, followed by drying and cold pressing. The lithium-containing phosphate comprised lithium iron phosphate.

[0326] The one-sided coating weight of the positive electrode active material layer was 300 mg / 1540.25 mm². 2 . 2. Production of the negative electrode sheet

[0327] The negative electrode sheet comprised a negative electrode tab, a negative electrode current collection section, and negative electrode active material layers arranged on both sides of the negative electrode current collection section, the negative electrode current collection section being a 6 µm thick copper foil.

[0328] The negative electrode active material layer was a film layer formed by uniformly applying the negative electrode paste (solvent: deionized water) to the surface of the negative electrode current collection section and subsequently drying and cold pressing.

[0329] The one-sided coating weight of the negative electrode active material layer was 130 mg / 1540.25 mm². 2 .

[0330] The negative electrode active material layer comprised a first negative electrode film layer and a second negative electrode film layer, wherein the first negative electrode film layer was located on the surface of the negative electrode current collecting section and the second negative electrode film layer was located on the surface of the first negative electrode film layer.

[0331] The first negative electrode film layer comprised a carbon-based material, a conductive agent made of acetylene carbon black, a negative electrode binder made of styrene-butadiene rubber, and a thickening agent made of sodium carboxymethylcellulose in a mass ratio of 96.5:1:1.5:1. The carbon-based material of the first negative electrode film layer comprised synthetic graphite and natural graphite in a mass ratio of 1:1, with the volume-averaged particle size of the carbon-based material being 9.0 µm.

[0332] The second negative electrode film layer comprised a carbon-based material, a conductive agent made of acetylene carbon black, a negative electrode binder made of styrene-butadiene rubber, and a thickening agent made of sodium carboxymethylcellulose in a mass ratio of 96.5:1:1.5:1. The carbon-based material of the second negative electrode film layer comprised synthetic graphite, with a volume-averaged particle size of 8.0 µm. 3. Separator

[0333] The separator comprised a base film, the base film being a 7 µm thick polyethylene film layer with a porosity of 42%. 4. Preparation of the electrolyte solution

[0334] The electrolyte solution comprised an organic solvent, a lithium salt, and an additive.

[0335] The organic solvent comprised 10% chain-like carboxylic acid ester solvent (ethyl acetate) and 75% carbonate solvent (diethyl carbonate, dimethyl carbonate and ethylene carbonate with a mass ratio of 1:1:1), whereby the mass fractions of the individual components in the organic solvent were calculated based on the mass of the electrolyte solution.

[0336] Based on the mass of the electrolyte solution, the mass fraction of the additive was 1.5%, comprising vinylene carbonate VC.

[0337] The lithium salt comprised 8.5% lithium hexafluorophosphate LiPF6 and 5% lithium bis(fluorosulfonyl)imide.

[0338] The conductivity of the electrolyte solution at room temperature was 12 mS / cm. 5. Manufacturing the battery cell

[0339] The positive electrode sheet, the separator, and the negative electrode sheet were stacked sequentially. The separator was positioned between the positive and negative electrode sheets to provide insulation, thus creating a stacked electrode assembly. The electrode assembly was placed in an outer packaging sleeve. After drying, the electrolyte solution was injected, and a battery cell was obtained by vacuum sealing, setting, formation, and shaping, etc. The compaction density of the positive electrode active material layer at 0% state of charge (SOC) of the battery cell was 2.5 g / cm³. 3 was, and the compaction density of the negative electrode active material layer at 0% SOC was 1.45 g / cm³ 3 fraud. Comparative example 1, embodiment 2 to embodiment 9

[0340] The battery cell was manufactured using a similar process to that described in embodiment 1. The difference from embodiment 1 was that the parameters of the positive electrode tab and the positive electrode active material layer in the positive electrode sheet were adapted, as detailed in Table 1. Performance tests: 1. Test of the DC internal resistance (DCR) of the battery cell

[0341] Reference can be made to the methods in GB / T 31467 “Test specification for high-performance lithium-ion traction batteries for HEV”.

[0342] For example, the battery cell was charged at 25°C with a constant current of 0.33C to 3.65V and left at rest for 1 minute; then it was charged with a constant current of 0.05C to 3.65V and left at rest for 30 minutes. The battery cell was then discharged with a constant current of 0.33C to 2.5V. The discharge capacity A0 was recorded in Ah at this point, then it was charged with a constant current of 0.33C to 0.5 A0Ah and set to 50% state of charge (SOC).

[0343] The battery cell was placed at 25 °C for 2 hours and then discharged with a constant current of 4 C for 10 seconds, where ΔU Entladung and ΔI Entladung The DCR data for the discharge of the lithium-ion battery were recorded. The DCR data were calculated using the following formula: RE Entladung = ΔU Entladung / ΔI Entladung , where ΔU Entladungrepresents the voltage change within 10 seconds after the start of the discharge and ΔI Entladung represents the current value within 10 seconds after the start of the discharge.

[0344] The test results are shown in Table 1. Table 1 Positive electrode sheet a (in mm) b (in mm) Maximum value of a 2 + b 2 (in mm 2 ) Battery cell Positive electrode tab Positive electrode active material layer DCR (inmΩ) Volume energy density (in Wh / L) Crowd position Distance between two adjacent electrode tabs on the same side of the positive electrode current collector section (in mm) Length (in mm) Width (in mm) Comparative example 1 1 (complete electrode tab) Executed on a short side / 650 100 650 0 422500 1,50 410 Comparative example 2 1 (complete electrode tab) / 300 80 300 0 90000 1,20 360 Comparative example 3 1 (complete electrode tab) / 680 100 680 0 462400 1,55 415 Example 1 2 Led out along a long side 200 500 100 100 100 20000 0,65 370 Example 2 4 25 500 100 100 12.5 10156 0,62 370 Example 3 1 (complete electrode tab) / 500 100 100 0 10000 0,62 370 Example 4 2 200 650 100 100 100 20000 0,65 380 Example 5 2 90 320 80 80 45 8425 0,62 350 Example 6 2 (complete electrode tabs) Leads out on both short sides, 1 electrode tab on one side / 400 100 200 0 40000 0,75 380 Example 7 / 500 100 250 0 62500 0,80 385 Example 8 / 600 100 300 0 90000 0,85 390 Example 9 / 650 100 325 0 105625 1,00 395

[0345] In Table 1, the positive electrode tab is arranged on at least one side of the positive electrode current collection section along the first direction. The negative electrode tab has a similar arrangement.

[0346] a represents the distance between the electron and the nearest electrode tab along the first direction; b represents the distance between the electron and the nearest electrode tab along the second direction; c represents the distance between the electron and the nearest electrode tab, where c 2 = a 2 + b 2 The maximum value of c 2corresponds to the maximum value of a 2 + b 2 That is, the maximum value of a 2 + b 2 can characterize the square of the longest electron transport path in the positive electrode sheet.

[0347] In each embodiment and comparative example, the electrode arrangement is a stacked electrode arrangement, and the electrode tabs of the positive and negative electrode sheets have an identical arrangement. The width of the positive electrode active material layer in the positive electrode sheet is 100 mm.

[0348] The positive electrode tabs extending from the short side mean that a positive electrode tab is located on at least one side of the positive electrode current collector section along its length. The positive electrode tabs extending from one short side mean that all positive electrode tabs are located on the same side of the positive electrode current collector section along its length. The positive electrode tabs extending from both short sides mean that multiple positive electrode tabs are located on both sides of the positive electrode current collector section along its length. With two positive electrode tabs, there is one positive electrode tab on each side of the positive electrode current collector section.

[0349] Extending the positive electrode tabs along the long side means that the positive electrode tab is located on at least one side of the positive electrode current collector section along the width direction. Extending the positive electrode tabs along one long side means that all positive electrode tabs are located on the same side of the positive electrode current collector section along the width direction.

[0350] Complete electrode tab refers to a ratio of the dimension W1 of the positive electrode tab to the dimension W2 of the positive electrode current collection section of 1, that is, n*W1 / W2 is 1, where n is 1.

[0351] In comparative example 1, the positive electrode active material layer has a large length and a high energy density. However, the positive electrode tab is located on one side of the positive electrode current collector section along the longitudinal direction, such that a is equal to the length of the positive electrode current collector section, i.e., a is again equal to the length of the positive electrode active material layer. Since the positive electrode tab is a full electrode tab whose width is equal to the width of the positive electrode active material layer, b is 0. This arrangement results in a long electron transport path along the longitudinal direction, causing a high internal resistance of the battery cell and thus impairing fast charging at high energy density.

[0352] In comparative example 2, the positive electrode active material layer has an excessive length and high energy density. However, the positive electrode tab is located on one side of the positive electrode current collector section along the longitudinal direction, such that a is equal to the length of the positive electrode current collector section, i.e., a in turn corresponds to the length of the positive electrode active material layer. Since the positive electrode tab is a full electrode tab whose width is equal to the width of the positive electrode active material layer, b is 0. This arrangement results in a long electron transport path along the longitudinal direction, causing a high internal resistance of the battery cell and thus impairing fast charging at high energy density.

[0353] In comparative example 3, the positive electrode tab is located on one side of the positive electrode current collector section along its length. Consequently, a is equal to the length of the positive electrode current collector section, i.e., a in turn corresponds to the length of the positive electrode active material layer. Since the positive electrode tab is a full electrode tab whose width corresponds to the width of the positive electrode active material layer, b is 0. While this arrangement results in a short electron transport path, the positive electrode active material layer has a short length, which negatively impacts the increase in the energy density of the battery cell.

[0354] In embodiments 6 to 9, the positive electrode tab is located on both sides of the positive electrode current collection section along its length. Consequently, a is equal to half the length of the positive electrode current collection section. Since the positive electrode tab is a full electrode tab whose width corresponds to the width of the positive electrode active material layer, b is zero. This arrangement ensures that the electron transport path along the length is not excessively long. The short electron transport path allows for a reduction in the internal resistance of the battery cell and thus facilitates fast charging at high energy density.

[0355] In embodiments 1 to 5, the positive electrode tab is located on one side of the positive electrode current collection section along the lateral direction. Due to the relatively small width of the positive electrode active material layer, the electron transport path along the lateral direction is kept short, which effectively reduces the internal resistance of the battery cell and consequently can promote fast charging at high energy density. With decreasing maximum value of a 2 + b 2 The electron transport path shortens further, which can reduce the internal resistance of the battery cell more effectively. However, a smaller maximum value of a 2 + b 2 This can also lead to a reduced energy density of the battery cell, which may prevent the requirements for high energy density from being met. Therefore, the maximum value of a 2 + b 2in the embodiments of the present application 6000 to 110000. This enables an effective increase in the energy density of the battery cell and its fast-charging performance, which facilitates the realization of fast charging at high energy density.

[0356] As in Fig. As shown in Figure 16, embodiment 1 has two positive electrode tabs, located on the same side of the positive electrode current collector section along the width direction. Here, a is 100 mm. The dimension of each positive electrode tab along the length direction is 125 mm, which defines W1 as 125 mm and n as 2. With W2 = 500 mm, n*W1 / W2 is 0.5. The distance Z1 between two adjacent positive electrode tabs is 200 mm, so b is half this distance and therefore b is 100 mm.

[0357] As in Fig.As shown in Figure 17, embodiment 2 has four positive electrode tabs, located on the same side of the positive electrode current collector section along the width direction. Here, a is 100 mm. The dimension of each positive electrode tab along the length direction is 100 mm, which defines W1 as 100 mm and n as 4. With W2 = 500 mm, n*W1 / W2 yields a value of 0.8. The distance Z1 between two adjacent positive electrode tabs is 25 mm. Consequently, b corresponds to half of this distance (for point A2) or half of the remaining dimension resulting from the positive electrode current collector section minus the dimension occupied by the positive electrode tabs and minus the dimension occupied by the gaps (for point A1). In both cases, b is 12.5 mm.

[0358] As in Fig.As shown in Figure 8, a positive electrode tab is present in embodiment 3. W1 is 500 mm and n is 1. With W2 = 500 mm, n*W1 / W2 yields a value of 1. And a is 100 mm, b is 0.

[0359] In embodiment 4, two positive electrode tabs are present, located on the same side of the positive electrode current collector section along the width direction. Here, a is 100 mm. The dimension of each positive electrode tab along the length direction is 162.5 mm, thus defining W1 as 162.5 mm and n as 2. With W2 = 650 mm, n*W1 / W2 yields a value of 0.5. The distance Z1 between two adjacent positive electrode tabs is 200 mm, so b corresponds to half this distance and is therefore 100 mm.

[0360] In embodiment 5, two positive electrode tabs are present, located on the same side of the positive electrode current collector section along the width direction. The length of a is 80 mm. The dimension of each positive electrode tab along the length direction is 80 mm, thus defining W1 as 80 mm and n as 2. With W2 = 320 mm, n*W1 / W2 yields a value of 0.5. The distance Z1 between two adjacent positive electrode tabs is 90 mm, so b is half this distance and therefore b is 45 mm.

[0361] Although illustrative embodiments have been demonstrated and described, the person skilled in the art should understand that the above embodiments should not be construed as limiting the embodiments of the present application and that changes, substitutions and modifications to the embodiments may be made without departing from the spirit, principles and scope of the embodiments of the present application. QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited non-patent literature

[0000] GB / T9722-2006

[0174] JIS / K0131-1996

[0284] Test standard GB / T 19077-2016

[0299]

Claims

[1] Battery cell comprising an electrode arrangement, wherein the electrode arrangement comprises a first electrode sheet and a second electrode sheet stacked along the thickness direction of the battery cell, one of the first electrode sheet and the second electrode sheet being a positive electrode sheet and the other being a negative electrode sheet, wherein the first electrode sheet and the second electrode sheet each comprise an electrode sheet main body and at least one electrode tab section, wherein an active material layer is arranged in at least one sub-region of the electrode sheet main body, and wherein the at least one electrode tab section is connected to the electrode sheet main body and projects out of the electrode sheet main body along a first direction, wherein the active material layer of the positive electrode sheet comprises a lithium-containing phosphate with an olivine structure and the dimension of the electrode sheet main body along the longitudinal direction of the battery cell is 320 mm to 650 mm, where the first electrode sheet fulfills the following condition: the maximum value of a 2 + b 2 is between 6000 and 110000, where a in the first electrode sheet along the first direction represents the distance between any point A of the electrode sheet main body and the electrode tab section that is closest to point A in at least one electrode tab section, in units of mm; where b in the first electrode sheet represents the distance between point A and the electrode tab section that is closest to point A in at least one electrode tab section along a second direction, in units of mm, one of the first direction and the second direction being parallel to the longitudinal direction and the other being parallel to the lateral direction of the battery cell. [2] Battery cell according to claim 1, wherein the first direction is parallel to the longitudinal direction of the battery cell. [3] Battery cell according to claim 2, wherein the first electrode sheet has several of the electrode tab sections, wherein several of the electrode tab sections are arranged on both sides of the electrode sheet main body along the first direction. [4] Battery cell according to claim 2 or 3, wherein the maximum value of a 2 + b 2 The number ranges from 25600 to 110000. [5] Battery cell according to claim 4, wherein the maximum value of a 2 + b 2 25600 to 90000. [6] Battery cell according to claim 1, wherein the first direction is parallel to the width direction of the battery cell. [7] Battery cell according to claim 6, wherein the at least one electrode tab section of the first electrode sheet is arranged on the same side of the electrode sheet main body along the first direction. [8] Battery cell according to claim 6 or 7, wherein the maximum value of a 2 + b 2 6400 to 45000. [9] Battery cell according to claim 8, wherein the maximum value of a 2 + b 2 6400 to 25000. [10] Battery cell according to any one of claims 1 to 9, wherein the dimension of the electrode sheet main body of the positive electrode sheet along the width direction is 80 mm to 150 mm. [11] Battery cell according to any one of claims 1 to 10, wherein several electrode tab sections are arranged on the same side of the electrode sheet main body in the first electrode sheet, wherein the distance between two adjacent electrode tab sections along the second direction is greater than 0 and less than or equal to 300 mm. [12] Battery cell according to any one of claims 1 to 11, wherein the second electrode sheet satisfies the following condition: the maximum value of c 2 + d 2 is between 6000 and 110000, where c in the second electrode sheet along the first direction represents the distance between any point B of the electrode sheet main body and the electrode tab section that is closest to point B in the at least one electrode tab section, in units of mm, wherein d along the second direction represents the distance between point B and the electrode tab section that is closest to point B in the at least one electrode tab section, in units of mm. [13] Battery cell according to any one of claims 1 to 12, wherein the first electrode sheet satisfies the following condition: n*W1 / W2 is 0.5 to 1.0, wherein n represents the number of all electrode tab sections on the same side of the electrode sheet main body, W1 represents the average dimension of the electrode tab section along the second direction, and W2 represents the dimension of the electrode sheet main body along the second direction. [14] Battery cell according to any one of claims 1 to 13, further comprising an electrolyte solution, wherein the electrolyte solution comprises a chain-like carboxylic acid ester solvent, wherein the mass fraction of the chain-like carboxylic acid ester solvent in the electrolyte solution is 5% to 30%. [15] Battery cell according to any one of claims 1 to 14, further comprising an electrolyte solution, wherein the electrolyte solution further comprises lithium hexafluorophosphate and lithium bis(fluorosulfonyl)imide, wherein the ratio of the mass fraction of lithium hexafluorophosphate to the mass fraction of lithium bis(fluorosulfonyl)imide is 0.5 to 4, based on the mass of the electrolyte solution. [16] Battery cell according to claim 14 or 15, wherein the conductivity of the electrolyte solution at room temperature is 10 mS / cm to 13 mS / cm. [17] Battery cell according to any one of claims 1 to 16, wherein the lithium-containing phosphate with olivine structure comprises lithium iron phosphate. [18] Battery cell according to claim 17, wherein the one-sided coating weight of the active material layer of the positive electrode sheet is 250 mg / 1540.25 mm² 2 up to 330 mg / 1540.25 mm 2 is, and / or the density of the active material layer of the positive electrode sheet is 2.30 g / cm³ 3 up to 2.70 g / cm³ 3 is the value when the battery cell is at a charge level of 0%. [19] Battery cell according to any one of claims 1 to 18, wherein the electrode sheet main body of the negative electrode sheet comprises a negative electrode current collection section and a negative electrode active material layer arranged on at least one side of the negative electrode current collection section, wherein the negative electrode active material layer comprises a carbon-based material, wherein the negative electrode active material layer comprises: a first negative electrode film layer arranged on the surface of the negative electrode current collecting section; and a second negative electrode film layer connected to a side of the first negative electrode film layer facing away from the negative electrode current collecting section, wherein the volume-averaged particle size Dv50 of the carbon-based material of the first negative electrode film layer is greater than or equal to the volume-averaged particle size Dv50 of the carbon-based material of the second negative electrode film layer. [20] Battery cell according to claim 19, wherein the carbon-based material of the first negative electrode film layer is in granular form, wherein the volume-averaged particle size Dv50 is 9.5 µm to 18.5 µm; and / or the carbon-based material of the second negative electrode film layer is in granular form, wherein the volume-averaged particle size Dv50 is 7.8 µm to 14.3 µm. [21] Battery cell according to claim 19 or 20, wherein the carbon-based material of the first negative electrode film layer comprises at least one of artificial graphite and natural graphite, and the carbon-based material of the second negative electrode film layer comprises artificial graphite. [22] Battery cell according to one of claims 1 to 21, wherein the one-sided coating weight of the active material layer of the negative electrode sheet is 120 mg / 1540.25 mm² 2 up to 180 mg / 1540.25 mm 2 is, and / or the compaction density of the active material layer of the negative electrode sheet is 1.30 g / cm³ 3 up to 1.65 g / cm³ 3 is the value when the battery cell is at a charge level of 0%. [23] Battery device comprising a battery cell according to any one of claims 1 to 22. [24] Power consumption device comprising a battery device according to claim 23.

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