Battery and power-consuming device

Abstract

Battery, including: several battery cells arranged along the thickness direction of the battery cells, the battery cell comprising a housing and an electrode arrangement received in the housing, wherein the expansion pressure of the battery cell in the thickness direction is 0.5 MPa to 2.4 MPa; and a first bus component that electrically connects at least two of the battery cells arranged along the thickness direction, wherein the first bus component has a multilayer structure, wherein the electrode arrangement comprises a positive electrode sheet, a negative electrode sheet and a separator arranged between the positive and negative electrode sheets, wherein the positive electrode sheet comprises a positive electrode current collector and a positive electrode film layer arranged on at least one side of the positive electrode current collector, wherein the positive electrode film layer comprises a positive electrode active material, wherein the positive electrode active material comprises a lithium-containing phosphate with an olivine structure, wherein the negative electrode sheet comprises a negative electrode current collector and a negative electrode film layer arranged on at least one side of the negative electrode current collector, wherein the negative electrode film layer comprises a negative electrode active material, wherein the negative electrode active material comprises a carbon-based material.

Description

Technical field

[0001] The present application relates to the technical field of batteries, in particular a battery and a power-consuming device. State of the art

[0002] Batteries are widely used in electronic devices such as mobile phones, laptops, electric bicycles, electric vehicles, electric airplanes, electric ships, electric toy cars, electric toy ships, electric toy airplanes and power tools, etc.

[0003] In the development of battery technology, improving the reliability of batteries represents a research direction in battery technology. Disclosure of the invention

[0004] The present application provides a battery and a power-consuming device, which can increase the reliability of the battery.

[0005] In a first aspect, the embodiments of the present application provide a battery comprising several battery cells and a first bus component. The several battery cells are arranged along the thickness direction of the battery cells, each battery cell comprising a housing and an electrode arrangement contained in the housing. The expansion pressure of the battery cell in the thickness direction is 0.5 MPa to 2.4 MPa. The first bus component electrically connects at least two of the battery cells arranged along the thickness direction, the first bus component having a multilayer structure.The electrode arrangement comprises a positive electrode sheet, a negative electrode sheet, and a separator arranged between the positive and negative electrode sheets, wherein the positive electrode sheet comprises a positive electrode current collector and a positive electrode film layer arranged on at least one side of the positive electrode current collector, wherein the positive electrode film layer comprises a positive electrode active material, the positive electrode active material comprising a lithium-containing phosphate with an olivine structure, wherein the negative electrode sheet comprises a negative electrode current collector and a negative electrode film layer arranged on at least one side of the negative electrode current collector, the negative electrode film layer comprising a negative electrode active material, the negative electrode active material comprising a carbon-based material.

[0006] The expansion pressure of the battery cell is related to the density of the electrode array. In the embodiments of the present application, the battery cell may be permitted to have an expansion pressure greater than or equal to 0.5 MPa in the thickness direction, thereby increasing the density of the electrode array and improving the energy density of the battery cell. If the expansion pressure of the battery cell in the thickness direction is less than or equal to 2.4 MPa, the deformation of the electrode array during the cycling process can be limited, the risk of wrinkling of the electrode array separator and the risk of an increase in the local distance between the positive and negative electrode sheets can be reduced, polarization can be reduced, and the cycle performance of the battery cell can be improved. The first bus component has a multilayer structure, with each layer of the first bus component capable of conducting current.This results in the first bus component having a large current-passing area, which reduces the heat generation of the first bus component and increases the fast-charging capability and reliability of the battery.

[0007] Provided the current-carrying area meets the requirements, the thickness of each layer of the first bus component can be reduced by designing it as a multilayer structure. During the cycling process, the battery cell expands, stretching the layered structure of the first bus component connected to the battery cell. This thin layered structure is easily deformable to accommodate the expansion and deformation of the battery cell. Consequently, at an expansion pressure of 0.5 MPa to 2.4 MPa, this reduces the risk of the connection between the battery cell and the first bus component failing and increases battery reliability.

[0008] By using the first bus component with a multi-layered structure, it can adapt to the expansion of the battery cell, ensuring both the current-carrying capacity and the deformation capacity of the first bus component simultaneously, thereby improving the reliability and fast-charging capability of the battery.

[0009] In some embodiments, the first bus component comprises a first bus layer and a second bus layer stacked on top of each other and connected to each other, the first bus layer connecting at least two of the battery cells arranged in the thickness direction.

[0010] Both the first and second bus layers can conduct current. This results in the first bus component having a large current-carrying area, which reduces heat generation and improves the battery's fast-charging capability and reliability. Provided the current-carrying area meets the required specifications, the first bus component can be designed as a double-layer structure, reducing the required thickness of the first bus layer. The battery cell expands during the cycling process, stretching the first bus layer. The first bus layer is thin and easily deformable to accommodate the battery cell's expansion, thus reducing the risk of the connection between the battery cell and the first bus layer tearing and increasing battery reliability.

[0011] In some embodiments, the battery cell includes an electrode terminal arranged on the housing, the electrode terminal being electrically connected to the electrode assembly. The portion of the first bus layer that does not overlap with the second bus layer is connected to the electrode terminal. The second bus layer can bypass the connection point between the first bus layer and the electrode terminal, thereby reducing the impact of the second bus layer on this connection point as the battery cell expands. This reduces the risk of the connection point between the electrode terminal and the first bus layer breaking and increases the reliability of the battery.

[0012] In some embodiments, the first bus layer is welded to the electrode connection, with a weld area between the first bus layer and the electrode connection being greater than or equal to 60 mm. 2This results in a larger current-passing area between the first bus layer and the electrode connection, which reduces heat generation at the weld point, decreases the temperature rise of the first bus layer during fast charging, and improves the fast-charging capability of the battery.

[0013] In some embodiments, the first bus component comprises at least one bent section, wherein the bent section connects the first bus layer and the second bus layer. The bent section can connect the first bus layer and the second bus layer and transmit current between the first bus layer and the second bus layer, thereby improving the current-carrying capability of the first bus component.

[0014] In some embodiments, the first bus layer comprises a first bus section, a second bus section, and a first buffer section, wherein the first bus section and the second bus section are arranged along the thickness direction and connected to different battery cells, and the first buffer section connects the first bus section and the second bus section. At least one of the first bus section and one of the second bus section is connected to the bending section.During the battery cell's cycle process, the battery cell expands and exerts a tensile force on the first bus layer; the first buffer section can reduce stresses by deformation, thus reducing the stress at the connection point between the first bus section and the battery cell, as well as the stress at the connection point between the second bus section and the battery cell, thereby reducing the risk of a connection failure between the first bus layer and the battery cell.

[0015] In some embodiments, the bending section is arranged so that it bypasses the first buffer section. The bending section is not directly connected to the first buffer section, thereby reducing the influence of the bending section on the deformation of the first buffer section and facilitating its deformation.

[0016] In some embodiments, the second bus layer comprises a first stacking section, a second stacking section, and a second buffer section, wherein the first stacking section is stacked with the first bus layer and connected by at least one of the bending sections, and the second stacking section is stacked with the second bus layer and connected by at least one of the bending sections. The second buffer section connects the first stacking section and the second stacking section. In the stacking direction of the first bus layer and the second bus layer, the second buffer section overlaps at least partially with the first buffer section.

[0017] During the battery cell's cycle process, the cell expands and exerts a tensile force on the first bus layer. Both the first and second buffer sections can relieve stresses through deformation, thereby reducing the risk of a connection failure between the first bus layer and the battery cell. The at least partial overlap of the second buffer section with the first buffer section brings their deformation zones closer together. This reduces the risk of the first and second buffer sections being damaged by other components during deformation.

[0018] In some embodiments, the second buffer section and the first buffer section are arranged next to each other to save space and improve current flow capability.

[0019] In some embodiments, the battery further comprises at least one second bus component, wherein the second bus component has a single-layer structure and connects at least two of the battery cells, and the thickness of the second bus component is greater than the thickness of the first bus layer and greater than the thickness of the second bus layer. Within the battery, the expansion rates of the battery cells can vary at different locations. For the battery cell with the lower expansion rate, a second bus component with a single-layer structure can be used; compared to the first bus component, the second bus component has a simpler structure, is easier to manufacture, and can reduce costs. The thickness of the second bus component is greater than the thickness of the first bus layer and greater than the thickness of the second bus layer, and its current-carrying capacity can meet the requirements.

[0020] In some embodiments, the sum of the thickness of the first bus layer and the thickness of the second bus layer equals the thickness of the second bus component. This reduces the difference in current-carrying capacity between the first and second bus components and improves current consistency.

[0021] In some embodiments, the battery cell located furthest out along the thickness direction is connected to the first bus component among the multiple battery cells. During charging, the expansion of several battery cells along the thickness direction can overlap, leading to a significant displacement of the battery cell located furthest out along the thickness direction. By using the first bus component with a multilayer structure to connect the outermost battery cell, the risk of a connection failure between the first bus component and the battery cell can be reduced.

[0022] In some embodiments, the thickness of the first bus layer is 1 mm to 2.5 mm, optionally 1.2 mm to 1.8 mm. In the embodiments of the present application, the thickness of the first bus layer is selected according to the expansion pressure of the battery cell, thereby ensuring, to a certain extent, both the current-carrying capacity and the deformation capacity of the first bus layer simultaneously, in order to improve the fast-charging capability and reliability of the battery.

[0023] In some embodiments, the thickness of the second bus layer is 1 mm to 2.5 mm, optionally 1.2 mm to 1.8 mm.

[0024] In some embodiments, the volume energy density of the battery cell is 390 Wh / L to 450 Wh / L and the thickness of the first bus layer is less than or equal to 2.5 mm; or the volume energy density of the battery cell is 450 Wh / L to 480 Wh / L and the thickness of the first bus layer is less than or equal to 2.2 mm.

[0025] The dimensions of the battery cell are related to its volume energy density. The present application specifies the thickness of the first bus layer according to the volume energy density of the battery cell, thereby ensuring, to a certain extent, both the current-carrying capacity and the deformation capacity of the first bus layer simultaneously, in order to improve the fast-charging capability and reliability of the battery.

[0026] In some embodiments, the negative electrode active material also comprises a silicon-based material. The mass fraction of the element silicon in the silicon-based material in the negative electrode active material is 1% to 6%; the thickness of the first bus layer is 1.2 mm to 2.2 mm and the thickness of the second bus layer is 1.2 mm to 2.2 mm.

[0027] The introduction of silicon-based material increases the capacity of the negative electrode layer and thus the energy density of the battery cell. This material also increases the expansion of the negative electrode layer during the cycling process. By precisely defining the thickness of the first bus layer and the second bus layer in combination with the silicon content, the risk of connection failure between the first bus layer and the battery cell can be reduced. Furthermore, the current-carrying capacity requirements of the first bus layer can be met.

[0028] In some embodiments, the first bus layer comprises a first bus section, a second bus section, and a first buffer section for connecting the first and second bus sections. The first and second bus sections are arranged along the thickness direction and connected to different parts of the battery cells. In the stacking direction of the first and second bus layers, the first buffer section projects beyond the first and second bus sections. A recess is provided at the position of the first buffer section in the first bus layer corresponding to this position. Providing this recess reduces the rigidity of the first buffer section, thus facilitating its deformation during battery cell expansion.

[0029] In some embodiments, the volume energy density of the battery cell is 390 Wh / L to 450 Wh / L and the depth of the depression is 1.2 mm to 2.5 mm; or the volume energy density of the battery cell is 450 Wh / L to 480 Wh / L and the depth of the depression is 1 mm to 2.2 mm.

[0030] The dimensions of the battery cell are related to its volume energy density. The present application specifies the depth of the recess according to the volume energy density of the battery cell, thereby ensuring, to a certain extent, both the current-carrying capacity and the deformation capacity of the first buffer section simultaneously, in order to improve the fast-charging capability and reliability of the battery.

[0031] In some embodiments, the electrode arrangement comprises two first surfaces and two second surfaces, wherein the two first surfaces are arranged opposite each other along the thickness direction and the two second surfaces are arranged opposite each other along a direction perpendicular to the thickness direction, and the second surface connects the two first surfaces. The area of ​​the first surface is larger than the area of ​​the second surface.

[0032] In some embodiments, the expansion pressure of the battery cell in the thickness direction is 1.5 MPa to 2.0 MPa. By limiting the expansion pressure of the battery cell in the thickness direction to the above range, the tensile force exerted by the battery cell on the first bus component during the battery cell's cycle process can be reduced, thereby reducing the risk of a connection failure between the battery cell and the first bus component and increasing the battery's reliability.

[0033] In some embodiments, the one-sided coating weight of the negative electrode film layer is 90 mg / 1540.25 mm². 2 up to 170 mg / 1540.25 mm 2 , optional 110 mg / 1540.25 mm 2 up to 150 mg / 1540.25 mm 2The one-sided coating weight of the negative electrode film layer is related to the expansion of the negative electrode film layer. By limiting the one-sided coating weight of the negative electrode film layer to the area mentioned above, both the energy density and the expansion pressure of the battery cell can be ensured to a certain extent simultaneously, thereby reducing the deformation of the battery cell and the risk of a connection failure between the battery cell and the first bus component.

[0034] In some embodiments, the compaction density of the negative electrode film layer at 100% SOC of the battery cell is 1.15 g / cm³. 3 up to 1.36 g / cm³ 3 , optional 1.25 g / cm² 3 up to 1.36 g / cm³ 3The density of the negative electrode film layer is related to the expansion of the battery cell at 100% charge. This is achieved by limiting the density of the negative electrode film layer to 1.15 g / cm³. 3 up to 1.36 g / cm³ 3 To a certain extent, both the energy density and the expansion pressure of the battery cell can be ensured simultaneously, thereby reducing the deformation of the battery cell and the risk of a connection failure between the battery cell and the first bus component.

[0035] If the density of the negative electrode film layer is within the above range, this is advantageous for increasing the energy density of the battery cell; and because the negative electrode active material is packed relatively densely in the negative electrode film layer, and the contact resistance between the particles is low, the resistance of the negative electrode sheet can be reduced, thereby decreasing heat generation.

[0036] If the density of the negative electrode film layer is within the range mentioned above, the fast-charging capability of the battery cell can be improved. A low density of the negative electrode film layer can increase the porosity of the negative electrode sheet, slow down its expansion, and reduce the expansion pressure of the battery cell.

[0037] In some embodiments, the porosity of the negative electrode sheet is between 27% and 40%. A negative electrode sheet porosity greater than or equal to 27% can provide space for impurities generated by side reactions of the negative electrode sheet, slow the expansion of the negative electrode sheet, reduce the expansion pressure of the battery cell, reduce the deformation of the battery cell, improve the cycle performance of the battery cell, and lower the risk of a connection failure between the battery cell and the first bus component. A negative electrode sheet porosity of less than or equal to 40% can simultaneously ensure the energy density of the battery cell.

[0038] In some embodiments, the carbon-based material comprises at least one synthetic graphite and one natural graphite. Both the synthetic and natural graphite exhibit excellent conductivity, which reduces heat generation in the negative electrode sheet and improves the fast-charging performance of the battery cell.

[0039] In some embodiments, the negative electrode active material also comprises a silicon-based material, wherein the mass fraction of the element silicon in the silicon-based material in the negative electrode active material is 0.3% to 10%, optionally 1% to 6%.

[0040] By introducing silicon-based material into the negative electrode sheet, both the capacity and the size of the negative electrode sheet can be increased. Therefore, by limiting the mass fraction of elemental silicon in the negative electrode active material to the above range, both the energy density and the size of the battery cell can be ensured to a certain extent simultaneously, thereby reducing battery cell deformation, improving the cycle life of the battery cell, and lowering the risk of connection failure between the battery cell and the first bus component.

[0041] In some embodiments, the silicon-based material comprises at least one silicon oxide compound and a silicon-carbon composite.

[0042] In some embodiments, the negative electrode film layer comprises a first negative electrode film layer and a second negative electrode film layer, the second negative electrode film layer being arranged between the first negative electrode film layer and the negative electrode current collector. The negative electrode active material comprises a first negative electrode active material arranged in the first negative electrode film layer and a second negative electrode active material arranged in the second negative electrode film layer, wherein the first negative electrode active material comprises synthetic graphite and the second negative electrode active material comprises one or more synthetic graphite, natural graphite, and silicon-based materials.The first negative electrode film layer and the second negative electrode film layer can be designed differently, thereby ensuring both the extent and the capacity of the negative electrode film layer to a certain extent simultaneously; the double-layer coating makes it possible to build up the pore difference of the negative electrode film layer, reduce the tortuosity of ion transport, reduce side reactions and improve the fast charging performance of the battery cell.

[0043] In some embodiments, the ratio of the thickness of the first negative electrode film layer to the thickness of the second negative electrode film layer is 3:7 to 7:3, optionally 4:6 to 6:4. By adjusting the ratio of the thickness of the first negative electrode film layer to the thickness of the second negative electrode film layer, the gradient pore difference between the upper and lower layers can be further increased, the tortuosity of lithium ion transport reduced, and the fast-charging capability of the battery cell improved.

[0044] In some embodiments, the thickness of the first negative electrode film layer is less than or equal to the thickness of the second negative electrode film layer, which can further improve the fast charging capability of the battery cell.

[0045] In some embodiments, the volume-averaged particle size Dv50 of the first negative electrode active material is less than or equal to the volume-averaged particle size Dv50 of the second negative electrode active material.

[0046] The particle size of the first and second negative electrode active materials differs, which can improve the fast-charging performance of the battery cell. During fast charging, the overpotential of the first negative electrode film layer is typically higher, and the bottleneck during fast charging is mainly in the first negative electrode film layer. In the embodiments of the present application, the particle size of the first negative electrode active material is relatively small, which can shorten the solid-phase transport path of the ions, improve fast-charging performance, and reduce the problem of ion deposition on the surface of the negative electrode sheet. The particle size of the second negative electrode active material is relatively large, which allows for the formation of larger pores in the second negative electrode film layer.During charging, the pores can absorb the expansion, thereby reducing the amount of expansion of the negative electrode film layer, reducing the force exerted by the battery cell on the first bus component, and lowering the risk of a connection failure between the battery cell and the first bus component.

[0047] In some embodiments, the volume-averaged particle size Dv50 of the first negative electrode active material is 7.8 µm to 14.3 µm, optionally 7.8 µm to 11.3 µm.

[0048] If the volume-averaged particle size Dv50 of the first negative electrode active material is set within the above range, the solid-phase transport path of 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; in addition, the first negative electrode active material within the above volume-averaged particle size range can interact with the second negative electrode active material, which is advantageous for establishing a gradient pore difference between the first negative electrode film layer and the second negative electrode film layer, reducing the tortuosity of lithium ion transport and improving the fast-charging performance of the battery cell.

[0049] In some embodiments, the volume-averaged particle size Dv50 of the second negative electrode active material is 9.5 µm to 18.5 µm, optionally 9.5 µm to 14.6 µm. If the volume-averaged particle size Dv50 of the second negative electrode active material is set within the above range, the pores of the second negative electrode film layer can be increased, which is advantageous for improving the fast-charging capability of the battery cell and reducing the expansion of the negative electrode film layer during charging.

[0050] In some embodiments, the specific surface area of ​​the negative electrode active material is 0.5 m². 2 / g up to 3 m 2 / g, optional 0.6 m 2 / g up to 1.2 m 2 / g. By limiting the specific surface area of ​​the negative electrode active material to greater than or equal to 0.5 m² 2The fast-charging capability of the battery cell can be increased by limiting the specific surface area of ​​the negative electrode active material to less than or equal to 3 m². 2 / g can reduce side reactions of the battery cell during storage and decrease the expansion pressure.

[0051] In some embodiments, the one-sided coating weight of the positive electrode film layer is 200 mg / 1540.25 mm². 2 up to 370 mg / 1540.25 mm 2 , optional 240 mg / 1540.25 mm 2 up to 330 mg / 1540.25 mm 2 If the one-sided coating weight of the positive electrode film layer is set within the above range, the amount of heat generated per unit area of ​​the positive electrode sheet can be limited, thus ensuring the simultaneous increase in energy density and charging rate performance of the battery cell.

[0052] In some embodiments, the compaction density of the positive electrode film layer at 100% SOC of the battery cell is 2.50 g / cm³. 3 up to 2.80 g / cm³ 3 , optional 2.55 g / cm² 3 up to 2.70 g / cm³ 3 If the density of the positive electrode film layer is within the above range, this is advantageous for increasing the energy density of the battery cell; and because the positive electrode active material in the positive electrode film layer is relatively densely packed, and the contact resistance between the particles is low, the resistance of the positive electrode sheet can be further reduced, thereby decreasing heat generation during fast charging.

[0053] In some embodiments, the porosity of the positive electrode sheet is between 25% and 32%. A positive electrode sheet porosity greater than or equal to 25% can provide space for impurities generated by side reactions of the positive electrode sheet, reduce the expansion pressure of the battery cell, reduce deformation of the battery cell, improve the cycle life of the battery cell, and lower the risk of a connection failure between the battery cell and the bus component. A positive electrode sheet porosity of less than or equal to 32% can, to some extent, simultaneously ensure the energy density of the battery cell.

[0054] In some embodiments, the thickness of the positive electrode sheet is 0.13 mm to 0.2 mm. By using a thinner positive electrode sheet, the migration path of ions can be shortened, the migration rate of ions increased, the heat generation of the battery cell reduced, and the fast-charging performance of the battery cell improved.

[0055] In some embodiments, the ratio of the thickness of the positive electrode current collector to the thickness of the positive electrode film layer is 0.05 to 0.3. By limiting the ratio of the thickness of the positive electrode current collector to the thickness of the positive electrode film layer to greater than or equal to 0.05, the current-carrying capacity of the positive electrode current collector can be increased, the temperature rise of the positive electrode sheet reduced, and the fast-charging performance of the battery cell improved; by limiting the ratio of the thickness of the positive electrode current collector to the thickness of the positive electrode film layer to less than or equal to 0.3, the capacity loss of the positive electrode sheet can be reduced.In the embodiments of the present application, the ratio of the thickness of the positive electrode current collector to the thickness of the positive electrode film layer is limited to the above range, thereby ensuring to some extent both the fast charging capability and the energy density of the battery cell simultaneously.

[0056] In some embodiments, the volume-averaged particle size of the positive electrode active material meets the conditions 1 µm ≤ Dv50 ≤ 2 µm and 0.4 µm ≤ Dv10 ≤ 0.7 µm. The particle size of the positive electrode active material is relatively small, resulting in a short deintercalation and intercalation path of lithium ions within the positive electrode active material and a low amount of heat generation. Furthermore, the particle size of the above positive electrode active material is not too small, thus reducing agglomeration during the processing and manufacturing process, and ensuring stable performance of the positive electrode active material.

[0057] In some embodiments, the battery cell comprises an electrolyte solution contained within the housing.

[0058] In some embodiments, the conductivity of the electrolyte solution at room temperature is 15 mS / cm to 20 mS / cm. If the conductivity of the electrolyte solution is within the above range, the migration rate of ions in the electrolyte solution is relatively high, 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.

[0059] In some embodiments, the electrolyte solution comprises an organic solvent consisting of one or more carbonate solvents and carboxylic acid ester solvents. The combination of organic solvents can improve the conductivity of the electrolyte solution and reduce its viscosity, thereby increasing the fast-charging performance of the battery.

[0060] In some embodiments, the carbonate solvent comprises one or more of ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate and ethyl methyl carbonate.

[0061] In some embodiments, the carboxylic acid ester comprises R1-COO-R2, wherein R1 and R2 each independently comprise an alkyl group with 1 to 5 carbon atoms or a halogenated alkyl group with 1 to 5 carbon atoms. 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.

[0062] In some embodiments, the electrolyte solution comprises a lithium salt, wherein the lithium salt comprises lithium bis(fluorosulfonyl)imide LiFSI and lithium hexafluorophosphate LiPF6, wherein the molar concentration of the lithium bis(fluorosulfonyl)imide LiFSI is 0.2 mol / L to 0.5 mol / L and the molar concentration of the lithium hexafluorophosphate LiPF6 is 0.5 mol / L to 1.0 mol / L.

[0063] In some embodiments, the density ρ of the electrolyte solution at room temperature satisfies the condition 1.05 g / mL ≤ ρ ≤ 1.35 g / mL. If the density ρ of the electrolyte solution is within the above 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 thus improving the fast-charging performance of the battery cell.

[0064] In some embodiments, the dimension of the electrode arrangement along the thickness direction is denoted by T, the thickness of the negative single-layer electrode sheet by T1, and the number of layers of the negative electrode sheet stacked in the thickness direction by N.

[0065] T, T1 and N satisfy the condition 0.3 ≤ (N × T1) / T ≤ 0.5.

[0066] During the battery cell's cycle process, the thickness of the negative electrode sheet increases due to irreversible side reactions, leading to cell expansion. Limiting (N × T1) / T to the above range can reduce this expansion and lower the risk of the battery cell becoming disconnected from the bus component.

[0067] In some embodiments, the charging time of the battery cell from 10% SOC to 80% SOC is 5 minutes to 10.5 minutes.

[0068] In a second aspect, the embodiments of the present application provide a power-consuming device comprising a battery according to one of the embodiments of the first aspect, wherein the battery serves to provide power. Brief description of the drawings

[0069] 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 vehicle according to some embodiments of the present application; Fig. Figure 2 is a schematic representation of a battery according to some embodiments of the present application; Fig. Figure 3 is a schematic exploded view of the battery cell according to some embodiments of the present application; Fig. Figure 4 is a schematic representation of a battery according to some embodiments of the present application; Fig. Figure 5 is an enlarged schematic view of the in Fig. 4 circled areas; Fig. Figure 6 is a schematic representation of the structure of a first bus component of Fig. 5; Fig. Figure 7 is a schematic representation of the connection of a battery cell with a first bus component according to some embodiments of the present application; Fig. Figure 8 is a schematic representation of an electrode arrangement of Fig. 3; Fig.Figure 9 is a schematic sectional view of the electrode arrangement of Fig. 8; Fig. Figure 10 is a schematic sectional view of a negative electrode sheet of a battery cell according to some embodiments of the present application; Fig. Figure 11 is a schematic sectional view of a positive electrode sheet of a battery cell according to some embodiments of the present application; Fig. Figure 12 is a schematic sectional view of a negative electrode sheet of a battery cell according to further embodiments of the present application; Fig. 13 is a schematic top view of a battery according to further embodiments of the present application; Fig. Figure 14 is an enlarged schematic view of the in Fig. 13 framed areas; and Fig. Figure 15 is a schematic representation of the structure of a second bus component of Fig. 14. Reference symbol list

[0070] 1. Vehicle; 2. Battery; 3. Control unit; 4. Motor; 10, battery cell; 100, battery cell array; 10a, large surface area; 10b, narrow surface area; 11, Electrode array; 111, Positive electrode sheet; 1111, Positive electrode current collector; 1112, Positive electrode film layer; 112, Negative electrode sheet; 1121, Negative electrode current collector; 1122, Negative electrode film layer; 11221, First negative electrode film layer; 11222, Second negative electrode film layer; 112a, Straight layer; 113, Separator; 11a, Main body section; 11b, Positive electrode tab; 11c, Negative electrode tab; 11d, First surface; 11e, Second surface; 11f, Third surface; 12, Housing; 121, Housing body; 122, End cover; 13, Electrode connection; 20, Box body; 21, Boundary beam; 22, Frame body; 23, Support beam; 24, Support plate; 30, bus component; 30a, first bus component; 30b, second bus component; 30c, third bus component; 31, first bus layer; 311, first bus section; 312, second bus section; 313, first buffer section; 314, recess; 32, second bus layer; 321, first stacking section; 322, second stacking section; 323, second buffer section; 33, bending section; X, thickness direction; Y, width direction; Z, height direction. Detailed descriptions

[0071] To clarify the objectives, technical solutions, and advantages of the embodiments of this application, the technical solutions in these embodiments are clearly described below in conjunction with the drawings. Obviously, the described embodiments represent only a subset of the embodiments of this application, but not all of them. All other embodiments that a person skilled in the art could have derived without creative effort based on the embodiments of this application fall within the scope of protection of this application.

[0072] Unless otherwise defined, all technical and scientific terms used herein have the same meanings as they are generally understood by engineers in the technical field to which this application relates. The terms used in the description of this application serve solely to describe specific embodiments and are not intended to limit the scope of this application. The terms "comprise" and "include," and all variations thereof, as used in the description and claims of this application and in the brief description of the drawings, are intended to convey non-exclusive inclusion. The terms "first," "second," etc., in the description, claims, or the above drawings of this application serve to distinguish between different objects and not to describe any particular order or priority relationship.

[0073] A reference to "embodiment" in the present application means that certain features, structures, or properties described in connection with an embodiment may be included in at least one embodiment of the present application. The appearance of the preceding phrase at different points in the description does not necessarily mean that it refers to the same embodiment, nor does it constitute an independent or alternative embodiment that is mutually exclusive with other embodiments.

[0074] In the description of this application, it should be noted that the terms "assemble," "connect," "couple," and "attach" should be interpreted broadly unless expressly stated and defined otherwise. They may, for example, refer to permanent connections, detachable connections, or integral connections; they may mean direct connections or indirect connections via an intermediate medium; and they may encompass internal communication between two components. A person skilled in the art will be able to understand the specific meaning of the above terms in this application within the relevant context.

[0075] The term “and / or” in the present application serves only to describe an associative relationship between the associated objects, indicating that three types of relationships can exist, such as A and / or B, which can represent the following three scenarios: A alone, both A and B, and B alone. Furthermore, the symbol “ / ” in the present application generally represents an “or” relationship between the front and back associated objects.

[0076] In the embodiments of the present application, the same reference numerals denote the same parts, and for the sake of brevity, detailed descriptions of the same parts in the various embodiments are omitted. It should be understood that the thickness, length, width, and other dimensions of various parts in the embodiments of the present application shown in the drawings, as well as the overall thickness, length, width, and other dimensions of the integrated device, are only examples and are not intended to limit the present application.

[0077] 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.

[0078] The term ‘several’ used in the present application refers to two or more (including two).

[0079] The term "parallel" encompasses not only the case of absolute parallelism, but also the case of approximate parallelism, which is commonly understood in engineering. The term "perpendicular" encompasses not only the case of absolute perpendicularity, but also the case of approximate perpendicularity, which is commonly understood in engineering.

[0080] Current market trends clearly show that the use of batteries is becoming increasingly widespread. Batteries are not only used in energy storage systems such as hydroelectric, thermal, wind, and solar power plants, but also extensively in electric vehicles such as e-bikes, e-motorcycles, and electric cars, as well as in many sectors such as aerospace. With the continuous expansion of battery applications, market demand is also rising steadily.

[0081] The battery refers to a single physical module comprising multiple battery cells to provide higher voltage and capacity. The battery cell is the smallest unit that makes up the battery. Multiple battery cells are typically electrically connected by bus components. During the battery cell's cycle process, electrochemical reactions occur internally, causing the battery cell to expand. This expansion exerts a tensile force on the bus component, increasing the risk of the battery cell becoming disconnected from the bus component and compromising reliability.To reduce the risk of a connection failure between the battery cell and the bus component, the thickness of the bus component can be reduced. This allows the bus component to dissipate stress through deformation as the battery cell expands, thus reducing the risk of a connection failure. However, reducing the thickness of the bus component reduces its current-carrying area, leading to increased temperature rise and resistance, and impairing the battery's fast-charging capability.

[0082] Against this background, the embodiments of the present application provide a battery which, through the rational design of the battery cell and the bus component, reduces the risk of a connection failure between the battery cell and the bus component, increases the current-carrying area of ​​the bus component and improves the fast-charging capability of the battery.

[0083] The battery described in the embodiments of the present application is suitable for a power-consuming device that uses a battery. The power-consuming device can be a device that uses a battery as a power source or various energy storage systems in which the battery serves as an energy storage element. The power-consuming device can be, for example, a mobile phone, a tablet, a laptop, an electric toy, a power tool, an electric bicycle, an electric vehicle, a ship, a spacecraft, etc., but is not limited to these. The electric toy can include stationary or mobile electric toys such as a game console, an electric toy car, an electric toy ship, and an electric toy airplane, etc., and the spacecraft can include an airplane, a rocket, a space transporter, and a spacecraft, etc.

[0084] For the sake of clarity, the following examples of implementation are illustrated using a vehicle as an example of a power-consuming device.

[0085] Fig. Figure 1 is a schematic representation of the structure of a vehicle according to some embodiments of the present application.

[0086] As in Fig. As shown in Figure 1, a battery 2 is located in vehicle 1. The battery 2 can be positioned at the bottom, front, or rear of vehicle 1. The battery 2 can be used to supply power to vehicle 1. For example, the battery 2 can be used as the operating power source for vehicle 1.

[0087] The vehicle 1 may further comprise a control unit 3 and a motor 4, wherein the control unit 3 is used to control the battery 2 to supply power to the motor 4, for example to meet the work power requirements of the vehicle 1 when starting, navigating and driving.

[0088] In some embodiments of the present application, the battery 2 can serve not only as an operating current source for the vehicle 1, but also as a drive current source for the vehicle 1, replacing fuel or natural gas wholly or partially, to provide the drive of the vehicle 1.

[0089] Fig. Figure 2 is a schematic representation of a battery according to some embodiments of the present application.

[0090] With reference to Fig. 2 In some embodiments, the battery 2 comprises a box body 20 and several battery cells 10 which are contained in the box body 20.

[0091] Battery cell 10 can be a secondary battery, where the secondary battery is a battery cell that can continue to be used by activating the active material through charging after the battery cell has been discharged.

[0092] For example, battery cell 10 can be a lithium-ion battery cell, a sodium-ion battery cell, a sodium-lithium-ion battery cell, a lithium-metal battery cell, a sodium-metal battery cell, a lithium-sulfur battery cell, a magnesium-ion battery cell, a nickel-metal hydride battery cell, a nickel-cadmium battery cell, or a lead-acid battery cell, etc.

[0093] For example, battery cell 10 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, wherein the polygonal battery is, for example, a hexagonal battery.

[0094] The multiple battery cells 10 can be connected in series, parallel, or in a mixed circuit, where a mixed circuit means that both series and parallel connections exist between the multiple battery cells 10. The multiple battery cells 10 can be connected directly in series, parallel, or in a mixed circuit, and the assembly formed from the multiple battery cells 10 can be housed in the box 20; of course, the multiple battery cells 10 can also first be connected in series, parallel, or in a mixed circuit to form a battery module, and several battery modules can then be further connected in series, parallel, or in a mixed circuit to form a whole and housed in the box 20.

[0095] In some embodiments, the battery 2 comprises several bus components, wherein the several bus components electrically connect the several battery cells 10 to each other.

[0096] In some embodiments, the box body 20 can be designed as part of a vehicle chassis. For example, part of the box body 20 can become at least part of the vehicle floor, or part of the box body 20 can become at least part of a cross member and a longitudinal member of the vehicle.

[0097] Fig. Figure 3 is a schematic exploded view of the battery cell according to some embodiments of the present application.

[0098] With reference to Fig. 3 In some embodiments, the battery cell 10 comprises a housing 12 and the electrode arrangement 11, which is received in the housing 12.

[0099] The housing 12 has a hollow structure, inside which a receiving chamber is formed for receiving the electrode assembly 11 and the electrolyte. The shape of the housing 12 can be determined according to the specific shape of the electrode assembly 11. If the electrode assembly 11 has a cuboid structure, a cuboid housing can be selected.

[0100] As an example, the housing 12 comprises a housing body 121 and an end cover 122, wherein the housing body 121 has an opening and the end cover 122 serves to cover the opening.

[0101] The housing body 121 is a component that serves to cooperate with the end cover 122 to form the inner cavity of the battery cell 10, the inner cavity formed being able to accommodate the electrode arrangement 11, the electrolyte and other components.

[0102] The housing body 121 and the end cap 122 can be separate components. For example, the housing body 121 can be provided with an opening, and the end cap 122 can cover the opening to form the inner cavity of the battery cell 10.

[0103] The housing body 121 can have various shapes and dimensions, for example, cuboid, cylindrical, hexagonal prismatic, and others. In particular, the shape of the housing body 121 can be determined according to the specific shape and size of the electrode arrangement 11. The housing body 121 can be made of various materials, for example, copper, iron, aluminum, stainless steel, aluminum alloy, etc., and the embodiments of the present application are not specifically limited in this respect.

[0104] The shape of the end cap 122 can be adapted to the shape of the housing body 121 to fit onto it. The material of the end cap 122 and the material of the housing body 121 can be the same or different. Optionally, the end cap 122 can be made of a material with a specific hardness and strength (e.g., copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc.). This prevents the end cap 122 from deforming easily under crushing or impact, allowing the battery cell 10 to have higher structural strength and improving reliability.

[0105] The end cover 122 is connected to the housing body 121 by welding, gluing, snapping or in some other way.

[0106] The housing body 121 can be open at one end or at both ends. In some examples, the housing body 121 can have a structure open at one end, with an end cap 122 provided and placed on the housing body 121. In other examples, the housing body 121 can have a structure open at both ends, with two end caps 122 provided, each of which is placed on one of the two openings of the housing body 121.

[0107] The electrode assembly 11 is a component in which electrochemical reactions take place in the battery cell 10. One or more electrode assemblies 11 can be contained in the housing body 121.

[0108] In some embodiments, the electrode arrangement 11 comprises a positive electrode sheet and a negative electrode sheet. During the charging and discharging process of the battery cell 10, the active ions (e.g., lithium ions) intercalate and deintercalate between the positive electrode sheet and the negative electrode sheet.

[0109] For example, the sections of the positive electrode sheet and the negative electrode sheet containing active substance form a main body section 11a of the electrode assembly 11, and the section of the positive electrode sheet without active substance forms a positive electrode tab 11b, and the section of the negative electrode sheet without active substance forms a negative electrode tab 11c. The positive electrode tab 11b and the negative electrode tab 11c can be located together at one end of the main body section 11a or each at one of the two ends of the main body section 11a.

[0110] In some embodiments, the electrode arrangement 11 also includes a separator that is arranged between the positive electrode sheet and the negative electrode sheet and serves mainly to prevent a short circuit between the positive and the negative electrode while simultaneously allowing the passage of active ions.

[0111] In some embodiments, the electrode arrangement 11 has a wound structure. The positive electrode sheet and the negative electrode sheet are wound into a coiled structure.

[0112] In some embodiments, the electrode arrangement 11 has a stacked structure.

[0113] For example, several positive electrode sheets and several negative electrode sheets can be provided, with the several positive electrode sheets and the several negative electrode sheets being stacked alternately.

[0114] For example, several positive electrode sheets can be provided while a negative electrode sheet is folded to form several stacked folded sections, with a positive electrode sheet sandwiched between adjacent folded sections.

[0115] As an example, both the positive electrode sheet and the negative electrode sheet are folded to form several stacked folded sections.

[0116] For example, several separators can be provided, each arranged between any adjacent positive or negative electrode sheets.

[0117] For example, a separator can be arranged continuously by folding or winding it between any adjacent positive or negative electrode sheets.

[0118] In some embodiments, the battery cell 10 also includes an electrode terminal 13 arranged on the housing 12; the electrode terminal 13 can be electrically connected to the electrode arrangement 11 to supply or dissipate electrical energy.

[0119] In some embodiments, the electrode connection 13 is electrically connected to the electrode tab. For example, two electrode connections 13 are provided, wherein the two electrode connections 13 are electrically connected to the positive electrode tab 11b and the negative electrode tab 11c, respectively.

[0120] Fig. Figure 4 is a schematic representation of a battery according to some embodiments of the present application; Fig.Figure 5 is an enlarged schematic view of the in Fig. 4 circled areas; Fig. Figure 6 is a schematic representation of the structure of a first bus component of Fig. 5; Fig. 7 is a schematic connection view of a battery cell and a first bus component according to some embodiments of the present application; Fig. Figure 8 is a schematic representation of an electrode arrangement of Fig. 3; Fig. Figure 9 is a schematic sectional view of an electrode arrangement of Fig. 8; Fig. Figure 10 is a schematic sectional view of a negative electrode sheet of a battery cell according to some embodiments of the present application; Fig. Figure 11 is a schematic sectional view of a positive electrode sheet of a battery cell according to some embodiments of the present application; Fig.Figure 12 is a schematic sectional view of a negative electrode sheet of a battery cell according to further embodiments of the present application.

[0121] With reference to Fig. 4 to Fig. 12. The embodiments of the present application provide a battery comprising several battery cells 10 and several bus components 30, wherein the several bus components 30 electrically connect the several battery cells 10 to each other.

[0122] The multiple bus components 30 can connect the multiple battery cells 10 in series, parallel or mixed configurations.

[0123] The several bus components 30 can have the same structure or different structures.

[0124] In some embodiments, the multiple battery cells 10 are arranged along the thickness direction X of the battery cell 10. The battery cell 10 comprises a housing 12 and an electrode arrangement 11 received in the housing 12. The expansion pressure of the battery cell 10 in the thickness direction X is 0.5 MPa to 2.4 MPa.

[0125] In some embodiments, the battery comprises a first bus component 30a, wherein the first bus component 30a electrically connects at least two of the battery cells 10, which are arranged along the thickness direction X. The first bus component 30a has a multilayer structure.

[0126] The electrode arrangement 11 comprises a positive electrode sheet 111, a negative electrode sheet 112, and a separator 113 arranged between the positive electrode sheet 111 and the negative electrode sheet 112. The positive electrode sheet 111 comprises a positive electrode current collector 1111 and a positive electrode film layer 1112 arranged on at least one side of the positive electrode current collector 1111, wherein the positive electrode film layer 1112 comprises a positive electrode active material, the positive electrode active material comprising a lithium-containing phosphate with an olivine structure.The negative electrode sheet 112 comprises a negative electrode current collector 1121 and a negative electrode film layer 1122 arranged on at least one side of the negative electrode current collector 1121, wherein the negative electrode film layer 1122 comprises a negative electrode active material, wherein the negative electrode active material comprises a carbon-based material.

[0127] The battery cells 10 can be arranged in a single row or in multiple rows. For example, a row of battery cells 10 can form a battery cell row 100, wherein the battery cell row 100 comprises at least two battery cells 10 arranged along the thickness direction X.

[0128] The battery cell 10 can comprise one or more electrode assemblies 11. Optionally, the electrode assemblies 11 are arranged along the thickness direction X.

[0129] Optionally, the expansion pressure of the battery cell 10 in the thickness direction X is 0.5 MPa, 0.6 MPa, 0.7 MPa, 0.8 MPa, 0.9 MPa, 1.0 MPa, 1.1 MPa, 1.2 MPa, 1.3 MPa, 1.4 MPa, 1.5 MPa, 1.6 MPa, 1.7 MPa, 1.8 MPa, 1.9 MPa, 2.0 MPa, 2.1 MPa, 2.2 MPa, 2.3 MPa or 2.4 MPa.

[0130] For example, the expansion pressure of battery cell 10 can be measured as follows:

[0131] At an ambient temperature of 45 °C, battery cell 10 is discharged to 2.0 V at a constant discharge rate of 1 C;

[0132] The battery cell 10 is clamped between two clamping plates, the two clamping plates being located on one side of the battery cell 10 along the thickness direction X and covering the large surface 10a (the large surface 10a is the surface of the battery cell 10 on one side in the thickness direction X);

[0133] At an ambient temperature of 45 °C, the battery cell is charged to 3.8 V at a constant charging rate of 0.8 C, and the pressure exerted by the battery cell on the terminal plates is detected and recorded;

[0134] According to the above charging and discharging strategy, the battery cell is cyclically charged and discharged until the battery cell reaches 70% SOH (i.e., the capacity retention rate of the battery cell = discharge capacity of the battery cell / nominal capacity of the battery cell = 70%), and the maximum pressure exerted by the battery cell on the terminal plates is recorded;

[0135] The expansion pressure Q of the battery cell in the thickness direction is calculated as: maximum pressure / area of ​​the large surface.

[0136] In the embodiments of the present application, the negative electrode film layer 1122 can be arranged only on one side of the negative electrode current collector 1121, or negative electrode film layers 1122 can be arranged on both sides of the negative electrode current collector 1121.

[0137] Optionally, the two surfaces of the negative electrode current collector 1121, which are arranged opposite each other along its thickness direction, are each provided with a negative electrode film layer 1122. The negative electrode film layers 1122 on the two surfaces of the negative electrode current collector 1121 can consist of the same negative electrode active material or of different negative electrode active materials; the thickness of the negative electrode film layers 1122 on the two surfaces of the negative electrode current collector 1121 can be the same or different.

[0138] For example, the negative electrode current collector 1121 can be a metal foil or a composite current collector. As an example of the metal foil, at least one foil made of copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver, and silver alloy can be used. The composite current collector can comprise a polymer material base layer and a metal material layer formed on at least one surface of the polymer material base layer. For example, the metal material in the metal material layer can comprise at least one of copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver, and silver alloy. For example, the polymer material base layer can comprise at least one of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), and polyethylene (PE).

[0139] The negative electrode active material comprises a carbon-based material. This carbon-based material exhibits high cycle stability, which improves the cycle performance of the battery cell.

[0140] The positive electrode current collector 1111 has two surfaces that are opposite each other in its own thickness direction, and the positive electrode film layer 1112 is arranged on one or both of the two opposite surfaces of the positive electrode current collector 1111.

[0141] For example, the positive electrode current collector 1111 can be a metal foil or a composite current collector. As an example of a metal foil, at least one foil made of aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver, and silver alloy can be used. The composite current collector can comprise a polymer material base layer and a metal material layer formed on at least one surface of the polymer material base layer. For example, the metal material of the metal material layer can include at least one of aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver, and silver alloy. For example, the polymer material base layer can include at least one of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), and polyethylene (PE).

[0142] The lithium-containing phosphate exhibits high cycle stability. Using lithium-containing phosphate as a positive electrode active material can reduce the cycle degradation of battery cell 10 caused by excessive temperature rise during fast charging.

[0143] The multiple bus components 30 can all be first bus components 30a or some can be first bus components 30a.

[0144] The expansion pressure of the battery cell 10 is related to the density of the electrode arrangement 11. In the embodiments of the present application, the battery cell 10 may be permitted to have an expansion pressure greater than or equal to 0.5 MPa in the thickness direction, thereby increasing the density of the electrode arrangement 11 and improving the energy density of the battery cell 10. If the expansion pressure of the battery cell 10 in the thickness direction X is less than or equal to 2.4 MPa, the deformation of the electrode arrangement 11 during the cycling process can be limited, the risk of wrinkling of the separator of the electrode arrangement 11 and the risk of an increase in the local distance between the positive and negative electrode sheets can be reduced, polarization can be reduced, and the cycle performance of the battery cell 10 can be improved.

[0145] The first bus component 30a has a multi-layered structure, with each layer capable of conducting current. This results in the first bus component 30a having a large current-conducting surface area, thereby reducing heat generation and increasing the fast-charging capability of battery 2.

[0146] Provided that the current-carrying area meets the requirements, the thickness of each layer of the first bus component 30a can be reduced by designing it as a multilayer structure. During the cycle process, the battery cell 10 expands, thereby stretching the layered structure of the first bus component 30a connected to the battery cell 10. The layered structure of the first bus component 30a is thin and easily deformable to accommodate the expansion and deformation of the battery cell 10. This reduces the risk of the connection between the battery cell 10 and the first bus component 30a tearing at an expansion pressure of 0.5 MPa to 2.4 MPa, thus increasing the reliability of the battery 2.

[0147] By using the first bus component with a multilayer structure according to the embodiments of the present application, it can adapt to the expansion of the battery cells, ensuring both the current-carrying capacity and the deformation capacity of the first bus component simultaneously, thereby improving the reliability and fast-charging capability of the battery.

[0148] In some embodiments, the first bus component 30a comprises a first bus layer 31 and a second bus layer 32, which are stacked on top of each other and connected to each other, wherein the first bus layer 31 connects at least two of the battery cells 10 which are arranged in the thickness direction X.

[0149] The first bus layer 31 and the second bus layer 32 can be formed as a single-piece structure. Alternatively, the first bus layer 31 and the second bus layer 32 can also be formed separately and joined by welding or other means.

[0150] Both the first bus layer 31 and the second bus layer 32 can transmit current. This results in the first bus component 30a having a large current-carrying area, which reduces heat generation in the first bus component 30a and increases the fast-charging capability and reliability of the battery. Provided that the current-carrying area meets the requirements, the required thickness of the first bus layer 31 can be reduced by designing the first bus component 30a as a double-layer structure. The battery cell 10 expands during the cycling process, which in turn stretches the first bus layer 31. The first bus layer 31 has a relatively small thickness. It is easily deformable to adapt to the deformation of the battery cell 10, thereby reducing the risk of the connection between the battery cell 10 and the first bus layer 31 tearing and increasing the reliability of the battery 2.

[0151] In some embodiments, the battery cell 10 comprises an electrode terminal 13 arranged on the housing 12, wherein the electrode terminal 13 is electrically connected to the electrode arrangement 11. The first bus layer 31 is connected to the electrode terminal 13 of the battery cell 10.

[0152] Optionally, the first bus layer 31 is welded to the electrode connection 13.

[0153] In some embodiments, the part of the first bus layer 31 that does not overlap with the second bus layer 32 is connected to the electrode terminal 13.

[0154] The second bus layer 32 can bypass the connection point between the first bus layer 31 and the electrode terminal 13, thereby reducing the impact of the second bus layer 32 on the connection point between the first bus layer 31 and the electrode terminal 13 during battery cell expansion. This reduces the risk of the connection point between the electrode terminal 13 and the first bus layer 31 breaking and increases the reliability of the battery 2. Furthermore, when assembling the battery cell 10 and the first bus component 30a, the area of ​​the first bus layer 31 used for connection to the electrode terminal 13 is not covered by the second bus layer 32, thus reducing assembly difficulty.

[0155] In some embodiments, the first bus layer 31 is welded to the electrode connection 13, wherein a weld area between the first bus layer 31 and the electrode connection 13 is greater than or equal to 60 mm. 2 is.

[0156] As an example, the first bus layer 31 is welded to the electrode connection 13, forming a weld track; the weld area can be the area of ​​the projection of the weld track along the thickness direction of the first bus layer. Optionally, the weld track is annular, with the inner and outer radii of the weld track being R1 and R2 respectively, and the weld area being π × (R2 2 - R1 2 ) amounts.

[0157] For example, the welding area between the first bus layer 31 and the electrode connection 13 is 60 mm. 2 , 70 mm 2 , 80 mm 2 , 90 mm 2 , 100 mm 2 , 110 mm 2 or 120 mm 2 .

[0158] According to the embodiments of the present application, it can be provided that a larger current passage area is available between the first bus layer 31 and the electrode connection 13, thereby reducing the heat generation at the weld point, decreasing the temperature rise of the first bus layer 31 during fast charging and improving the fast charging capability of the battery.

[0159] In some embodiments, the second bus layer 32 does not cover the weld track.

[0160] In some embodiments, the second bus layer 32 partially overlaps with the electrode terminal 13 in the stacking direction of the first bus layer 31 and the second bus layer 32, which shortens the conduction path between the second bus layer 32 and the electrode terminal 13, thereby reducing resistance and heat generation.

[0161] In some embodiments, the first bus layer 31 and the second bus layer 32 are stacked along the height direction Z of the battery cell 10. In other words, the stacking direction of the first bus layer 31 and the second bus layer 32 runs parallel to the height direction Z. For example, the height direction Z runs perpendicular to the thickness direction X.

[0162] In some embodiments, the second bus layer 32 can be arranged on the side of the first bus layer 31 facing the battery cell 10 or on the side of the first bus layer 31 facing away from the battery cell 10.

[0163] In some embodiments, the first bus component 30a comprises at least one bending section 33, wherein the bending section 33 connects the first bus layer 31 and the second bus layer 32.

[0164] One or more bending sections 33 may be provided.

[0165] The bending section 33 can connect the first bus layer 31 and the second bus layer 32 and transfer current between the first bus layer 31 and the second bus layer 32, thereby improving the current-carrying capability of the first bus component 30a.

[0166] In some embodiments, the first bus layer 31 comprises a first bus section 311, a second bus section 312, and a first buffer section 313, wherein the first bus section 311 and the second bus section 312 are arranged along the thickness direction X and connected to different battery cells 10, and the first buffer section 313 connects the first bus section 311 and the second bus section 312 to each other. At least one of the first bus section 311 and the second bus section 312 is connected to the bending section 33.

[0167] The first bus section 311 can be connected to the electrode terminal 13 of one battery cell 10 or simultaneously to the electrode terminals 13 of at least two battery cells 10. The second bus section 312 can be connected to the electrode terminal 13 of one battery cell 10 or simultaneously to the electrode terminals 13 of at least two battery cells 10.

[0168] During the cycle process of battery cell 10, the battery cell 10 expands and exerts a tensile force on the first bus layer 31; the first buffer section 313 can reduce stresses by deformation, thereby reducing the load at the connection point between the first bus section 311 and the battery cell 10 as well as the load at the connection point between the second bus section 312 and the battery cell 10 and reducing the risk of a connection failure of the first bus layer 31 with the battery cell 10.

[0169] In some embodiments, the bending section 33 is arranged such that it bypasses the first buffer section 313. The bending section 33 is not directly connected to the first buffer section 313, thereby reducing the influence of the bending section 33 on the deformation of the first buffer section 313 and facilitating the deformation of the first buffer section 313.

[0170] In some embodiments, the first bus layer 31 and the second bus layer 32 are arranged adjacent to each other. Optionally, apart from the bending section 33, there is no further fixed connection between the first bus layer 31 and the second bus layer 32. Alternatively, a conductive adhesive can be arranged between the first bus layer 31 and the second bus layer 32.

[0171] In some embodiments, the first bus section 311 is arranged above the electrode terminal 13 of the battery cell 10, and the second bus section 312 is arranged above the electrode terminal 13 of the battery cell 10.

[0172] In some embodiments, the first buffer section 313 comprises an arc-shaped structure.

[0173] In some embodiments, the first bus section 311 is connected to the second bus layer 32 by at least one of the bending sections 33, and the second bus section 312 is connected to the second bus layer 32 by at least one of the bending sections 33.

[0174] In some embodiments, the second bus layer 32 comprises a first stacking section 321, a second stacking section 322, and a second buffer section 323, wherein the first stacking section 321 is stacked with the first bus section 311 and connected by at least one of the bending sections 33, and the second stacking section 322 is stacked with the second bus section 312 and connected by at least one of the bending sections 33. The second buffer section 323 connects the first stacking section 321 and the second stacking section 322. In the stacking direction of the first bus layer 31 and the second bus layer 32, the second buffer section 323 overlaps at least partially with the first buffer section 313.

[0175] During the cycle process of battery cell 10, the battery cell 10 expands and exerts a tensile force on the first bus layer 31; both the first buffer section 313 and the second buffer section 323 can relieve stresses through deformation, thereby reducing the risk of a connection failure between the first bus layer 31 and the battery cell 10. The at least partial overlap of the second buffer section 323 with the first buffer section 313 results in the deformation areas of the first buffer section 313 and the second buffer section 323 being closer together. This reduces the risk of the first buffer section 313 and the second buffer section 323 being damaged by other parts during deformation.

[0176] In some embodiments, the second buffer section 323 and the first buffer section 313 are arranged adjacent to each other. The embodiments of the present application can save space and improve current flow capacity.

[0177] In some embodiments, the outer surface of the battery cell 10 comprises two large surfaces 10a and two narrow surfaces 10b. The two large surfaces 10a are arranged opposite each other along the thickness direction X, and the two narrow surfaces 10b are arranged opposite each other along the width direction Y of the battery cell. The two ends of the large surface 10a along the width direction Y are connected to the two narrow surfaces 10b. The area of ​​the large surface 10a is larger than the area of ​​the narrow surface 10b.

[0178] In some embodiments, the thickness direction X, the width direction Y and the height direction Z are pairwise perpendicular to each other.

[0179] In some embodiments, the multiple battery cell rows 100 are arranged along the lateral direction Y.

[0180] In some embodiments, the expansion pressure of the battery cell 10 in the thickness direction X is 1.5 MPa to 2.0 MPa.

[0181] In the embodiments of the present application, the expansion pressure of the battery cell 10 in the thickness direction X is limited to 1.5 MPa to 2.0 MPa in order to reduce the tensile force exerted by the battery cell on the first bus component during the cycle process of the battery cell, to reduce the risk of a connection failure of the battery cell with the first bus component and to increase the reliability of the battery.

[0182] In some embodiments, the thickness of the first bus layer is 31 1 mm to 2.5 mm, optionally 1.2 mm to 1.8 mm.

[0183] For example, the thickness of the first bus layer is 31 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 mm, 2.1 mm, 2.2 mm, 2.3 mm, 2.4 mm or 2.5 mm.

[0184] In the embodiments of the present application, the thickness of the first bus layer 31 is selected according to the expansion pressure of the battery cell 10, whereby the current-carrying capacity of the first bus layer 31 and the deformation capacity of the first bus layer 31 can be ensured to a certain extent simultaneously in order to improve the fast-charging capability and reliability of the battery 2.

[0185] In some embodiments, the thickness of the second bus layer 32 is 1 mm to 2.5 mm, optionally 1.2 mm to 1.8 mm. For example, the thickness of the second bus layer 32 is 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 mm, 2.1 mm, 2.2 mm, 2.3 mm, 2.4 mm or 2.5 mm.

[0186] The thickness of the second bus layer 32 can be selected based on the thickness of the first bus layer 31 and the current-carrying capacity of the first bus component required for the battery. For example, the second bus layer 32 can have a greater thickness than the first bus layer 31 if the thickness of the first bus layer 31 is small, in order to increase the current-carrying capacity of the first bus component.

[0187] In some embodiments, the volume energy density of the battery cell is 10 390 Wh / L to 450 Wh / L and the thickness of the first bus layer 31 is less than or equal to 2.5 mm.

[0188] The volume energy density of the battery cell 10 has a meaning known in engineering and can be determined using devices and methods known in engineering.

[0189] The dimensions of the battery cell 10 are related to its volume energy density. The present application specifies the thickness of the first bus layer 31 according to the volume energy density of the battery cell 10, thereby ensuring, to a certain extent, both the current-carrying capacity and the deformation capacity of the first bus layer 31 simultaneously, in order to improve the fast-charging capability and reliability of the battery 2.

[0190] In some embodiments, the volume energy density of the battery cell is 10 450 Wh / L to 480 Wh / L and the thickness of the first bus layer 31 is less than or equal to 2.2 mm.

[0191] The dimensions of the battery cell 10 are related to its volume energy density. In a battery 2 that uses battery cells 10 with high volume energy density, the thickness of the first bus layer 31 must be reduced. In the embodiments of the present application, the thickness of the first bus layer 31 is selected according to the volume energy density of the battery cell 10, thereby ensuring, to a certain extent, both the current-carrying capacity and the deformation capacity of the first bus layer 31 simultaneously, in order to improve the fast-charging capability and reliability of the battery 2.

[0192] In some embodiments, the negative electrode active material also comprises a silicon-based material. The mass fraction of the element silicon in the silicon-based material in the negative electrode active material is 1% to 6%; the thickness of the first bus layer 31 is 1.2 mm to 2.2 mm and the thickness of the second bus layer 32 is 1.2 mm to 2.2 mm.

[0193] For example, the mass fraction of the element silicon in the silicon-based material in the negative electrode active material is 1%, 2%, 3%, 4%, 5%, or 6%. For example, the thickness of the first bus layer 31 is 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 mm, 2.1 mm, or 2.2 mm. For example, the thickness of the second bus layer 32 is 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 mm, 2.1 mm, or 2.2 mm.

[0194] The introduction of the silicon-based material increases the capacity of the negative electrode sheet 112 and the energy density of the battery cell 10. The introduction of the silicon-based material also increases the expansion of the negative electrode sheet 112 during the cycling process. By specifying the thickness of the first bus layer 31 and the thickness of the second bus layer 32 in combination with the silicon content, the risk of a connection failure between the first bus layer 31 and the battery cell 10 due to the introduction of the silicon-based material can be reduced. Furthermore, the current-carrying capacity requirements of the first bus component 30a can be met.

[0195] In some embodiments, the first bus layer 31 comprises a first bus section 311, a second bus section 312, and a first buffer section 313 for connecting the first bus section 311 and the second bus section 312, wherein the first bus section 311 and the second bus section 312 are arranged along the thickness direction X and connected to different battery cells 10. In the stacking direction of the first bus layer 31 and the second bus layer 32, the first buffer section 313 projects beyond the first bus section 311 and the second bus section 312. A recess 314 is provided at the position of the first bus layer 31 corresponding to the first buffer section 313.

[0196] By providing the recess 314, the strength of the first buffer section 313 can be reduced, which facilitates the deformation of the first buffer section 313 when the battery cell 10 expands.

[0197] In some embodiments, the volume energy density of the battery cell is 10 390 Wh / L to 450 Wh / L and the depth H2 of the recess 314 is 1.2 mm to 2.5 mm.

[0198] The dimensions of the battery cell 10 are related to its volume energy density. The present application specifies the depth of the recess 314 according to the volume energy density of the battery cell 10, thereby ensuring, to a certain extent, both the current-carrying capacity and the deformation capacity of the first buffer section 313 simultaneously, in order to improve the fast-charging capability and reliability of the battery 2.

[0199] In some embodiments, the volume energy density of the battery cell is 10 450 Wh / L to 480 Wh / L and the depth of the recess 314 is 1 mm to 2.2 mm.

[0200] The dimensions of the battery cell 10 are related to its volume energy density. In a battery 2 that uses battery cells 10 with high volume energy density, the difficulty of deformation of the first buffer section 313 must be reduced. In the embodiments of the present application, the depth of the recess 314 is determined according to the volume energy density of the battery cell 10, thereby ensuring, to a certain extent, both the current-carrying capacity and the deformation capacity of the first buffer section 313 simultaneously, in order to improve the fast-charging capability and reliability of the battery 2.

[0201] In some embodiments, the battery 2 further comprises a box body 20. The box body 20 serves to accommodate the multiple battery cells 10. The box body 20 comprises at least two limiting beams 21, wherein two adjacent limiting beams 21 are arranged along the thickness direction X and multiple battery cells 10 are arranged between the adjacent limiting beams 21.

[0202] For example, at least one row of battery cells 100 is arranged between any two adjacent boundary bars 21.

[0203] The limiting beam 21 can be used to limit the expansion deformation of the battery cell 10 in the thickness direction X. The limiting beam 21 can be in direct contact with the battery cell 10 in the thickness direction X; alternatively, other components can be arranged between the limiting beam 21 and the battery cell 10, i.e., the limiting beam 21 limits the expansion of the battery cell 10 via this component.

[0204] The limiting bar 21 can limit the expansion of the battery cell 10 during the battery cycle process in order to reduce the tensile force exerted by the battery cell 10 on the first bus component 30a, to reduce the risk of a connection failure of the battery cell 10 with the first bus component 30a and to increase the reliability of the battery.

[0205] In some embodiments, the electrode arrangement 11 comprises two first surfaces 11d and two second surfaces 11e, wherein the two first surfaces 11d are arranged opposite each other along the thickness direction X, and the two second surfaces 11e are arranged opposite each other along a direction perpendicular to the thickness direction X, and the second surface 11e connects the two first surfaces 11d. The area of ​​the first surface 11d is larger than the area of ​​the second surface 11e.

[0206] By arranging the first surface 11d with a larger area compared to the boundary beam 21 along the thickness direction X, the load-bearing area of ​​the boundary beam 21 can be increased and the deformation of the boundary beam 21 reduced when the electrode arrangement 11 is extended.

[0207] In some embodiments, the boundary bar 21 extends along the width direction Y.

[0208] In some embodiments, the two second surfaces 11e are arranged opposite each other along the width direction Y.

[0209] In some embodiments, the main body section 11a comprises two first surfaces 11d, two second surfaces 11e and two third surfaces 11f; the two third surfaces 11f are arranged at both ends of the battery cell 10 along the vertical direction Z, and the third surfaces 11f are connected to the two first surfaces 11d and the two second surfaces 11e.

[0210] The positive electrode tab 11b and the negative electrode tab 11c extend from the same third surface 11f, or the positive electrode tab 11b and the negative electrode tab 11c each extend from one of the two third surfaces 11f.

[0211] In some embodiments, at least part of the second surface 11e is arc-shaped. Optionally, the electrode arrangement 11 has a wound structure, and the second surface 11e is an arc-shaped surface.

[0212] In some embodiments, the large surface 10a runs parallel to the first surface 11d.

[0213] In some embodiments, the battery cell 10 is a square battery cell. Optionally, the narrow surface 10b runs perpendicular to the large surface 10a.

[0214] In some embodiments, part of the negative electrode current collector 1121 is not covered by the negative electrode film layer 1122; the part of the negative electrode current collector 1121 not covered by the negative electrode film layer 1122 can be used to form a negative electrode tab 11c.

[0215] In some embodiments, the thickness of the negative electrode current collector 1121 is 4 µm to 6 µm. For example, the thickness of the negative electrode current collector 1121 is 4 µm, 4.5 µm, 5 µm, 5.5 µm or 6 µm, or lies in a range consisting of any two of the above values.

[0216] In some embodiments, the compaction density of the negative electrode film layer 1122 at 100% SOC of the battery cell is 1.15 g / cm³. 3 up to 1.36 g / cm³ 3 For example, the compaction density of the negative electrode film layer 1122 in battery cell 10 at a 100% charge level is 1.15 g / cm³. 3 , 1.18 g / cm³ 3 , 1.20 g / cm³ 3 , 1.22 g / cm³ 3 , 1.25 g / cm³ 3 , 1.28 g / cm³ 3 , 1.3 g / cm³ 3 , 1.32 g / cm³ 3 , 1.35 g / cm³ 3 or 1.36 g / cm³ 3 , or lies within a range consisting of any two of the above values.

[0217] For example, 100% SOC (state of charge) and 0% SOC are defined as follows:

[0218] 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, corresponding to a 100% state of charge (SOC). The battery cell is then discharged at a constant rate of 0.33C down to the final discharge voltage, corresponding to a 0% SOC. For example, the upper charging limit voltage of the battery could be 3.8V; the discharge cut-off voltage could be 2.0V.

[0219] For example, the density of the negative electrode film layer in a battery cell at 100% state of charge (SOC) has a well-known significance in engineering. The negative electrode sheet is removed from the battery cell at 100% state of charge (SOC), and the density of the negative electrode film layer is measured. For instance, a single-sided coated negative electrode sheet (in the case of a double-sided coated electrode sheet, the negative electrode film layer can be wiped off one side first) is taken, then punched into small discs with an area S1, weighed, and its weight recorded as M1. Its thickness H1 is then measured. Next, the negative electrode film layer of the previously weighed negative electrode sheet is wiped off, the resulting negative electrode current collector is weighed, its weight recorded as M0, and its thickness H0 is measured.The one-sided coating weight of the negative electrode film layer = (the weight of the negative electrode sheet M1 - the weight of the negative electrode current collector M0) / S1, the thickness of the negative electrode film layer = the thickness of the negative electrode sheet H1 - the thickness of the negative electrode current collector H0, the compaction density of the negative electrode film layer = the one-sided coating weight of the negative electrode film layer / the thickness of the negative electrode film layer.

[0220] The density of the negative electrode film layer 1122 is related to the expansion of the battery cell 10 at 100% charge. This is achieved by limiting the density of the negative electrode film layer 1122 to 1.15 g / cm³. 3 up to 1.36 g / cm³ 3To a certain extent, both the energy density and the expansion pressure of the battery cell 10 can be ensured simultaneously, thereby reducing the deformation of the battery cell 10 and the risk of a connection failure of the battery cell 10 with the bus component.

[0221] If the compaction density of the negative electrode film layer 1122 is within the above range, this is advantageous for increasing the energy density of the battery cell 10; and because the negative electrode active material in the negative electrode film layer 1122 is relatively densely packed and the contact resistance between the particles is low, the resistance of the negative electrode sheet 112 can be further reduced and the heat generation thereby decreased.

[0222] If the density of the negative electrode film layer 1122 is within the range above, the fast-charging capability of the battery cell 10 can be improved. A low density of the negative electrode film layer 1122 can increase the porosity of the negative electrode sheet 112, slow down the expansion of the negative electrode sheet, and reduce the expansion pressure of the battery cell 10.

[0223] In some embodiments, the compaction density of the negative electrode film layer 1122 at 100% SOC of the battery cell is 1.25 g / cm³. 3 up to 1.36 g / cm³ 3 , which can improve the energy density of battery cell 10.

[0224] In some embodiments, the one-sided coating weight of the negative electrode film layer is 1122 90 mg / 1540.25 mm². 2 up to 170 mg / 1540.25 mm 2For example, the one-sided coating weight of the negative electrode film layer is 1122 90 mg / 1540.25 mm². 2 , 92 mg / 1540.25 mm 2 , 95 mg / 1540.25 mm 2 , 96 mg / 1540.25 mm 2 , 100 mg / 1540.25 mm 2 , 102 mg / 1540.25 mm 2 , 104 mg / 1540.25 mm 2 , 105 mg / 1540.25 mm 2 , 108 mg / 1540.25 mm 2 , 110 mg / 1540.25 mm 2 , 112 mg / 1540.25 mm 2 , 114 mg / 1540.25 mm 2 , 115 mg / 1540.25 mm 2 , 116 mg / 1540.25 mm 2 , 118 mg / 1540.25 mm 2 , 120 mg / 1540.25 mm 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 , 142 mg / 1540.25 mm 2 , 145 mg / 1540.25 mm 2 , 148 mg / 1540.25 mm 2 , 150 mg / 1540.25 mm 2, 152 mg / 1540.25 mm 2 , 155 mg / 1540.25 mm 2 , 160 mg / 1540.25 mm 2 , 165 mg / 1540.25 mm 2 , 167 mg / 1540.25 mm 2 or 170 mg / 1540.25 mm 2 , or lies within a range consisting of any two of the above values.

[0225] The one-sided coating weight of the negative electrode film layer 1122 is related to the extent of the negative electrode film layer. This is achieved by limiting the one-sided coating weight of the negative electrode film layer 1122 to 90 mg / 1540.25 mm². 2 up to 170 mg / 1540.25 mm 2 To a certain extent, both the energy density and the expansion pressure of the battery cell 10 can be ensured simultaneously, thereby reducing the deformation of the battery cell 10 and reducing the risk of a connection failure of the battery cell 10 with the bus component.

[0226] Furthermore, by limiting the one-sided coating weight of the negative electrode film layer 1122 to 90 mg / 1540.25 mm 2 up to 170 mg / 1540.25 mm 2 the amount of heat generated by the negative electrode sheet 112 per unit area is limited and the temperature rise of the battery cell 10 is reduced, especially during fast charging.

[0227] In some embodiments, the one-sided coating weight of the negative electrode film layer is 1122,110 mg / 1540.25 mm². 2 up to 150 mg / 1540.25 mm 2 , in order to continue to simultaneously ensure the energy density and expansion pressure of battery cell 10.

[0228] In some embodiments, the porosity of the negative electrode sheet 112 is 27% to 40%. For example, the porosity of the negative electrode sheet 112 can be 27%, 28%, 29%, 30%, 31%, 32%, 33%, 34%, 35%, 36%, 37%, 38%, 39%, or 40%.

[0229] The porosity of the negative electrode sheet can be defined as the percentage of the pore volume within the negative electrode sheet relative to the total volume of the negative electrode sheet. As an example, a double-sided coated negative electrode sheet is used for a battery cell at 0% charge; the porosity of the negative electrode sheet is measured with an AccuPyc II 1340 density analyzer according to the national standard GB / T 24586-2009.

[0230] In the embodiments of the present application, a porosity of the negative electrode sheet 112 greater than or equal to 27% can provide space for impurities formed by side reactions of the negative electrode sheet 112, slow down the expansion of the negative electrode sheet 112, reduce the expansion pressure of the battery cell 10, reduce the deformation of the battery cell 10, improve the cycle performance of the battery cell 10, and lower the risk of a connection failure between the battery cell and the bus component. A porosity of the negative electrode sheet 112 less than or equal to 40% can simultaneously ensure the energy density of the battery cell 10.

[0231] In some embodiments, the carbon-based material comprises graphite particles, wherein the degree of graphitization of the graphite particles is between 92.0% and 94.5%. For example, the degree of graphitization of the graphite particles is 92.0%, 92.5%, 93%, 93.5%, 94%, or 94.5%, or lies within a range consisting of any two of the above values.

[0232] If the graphitization degree of the graphite particles is within the above range, the graphite particles exhibit excellent conductivity, which reduces the heat generation of the negative electrode sheet 112 and the battery cell 10; in addition, the fast charging performance of the battery cell 10 can be improved.

[0233] In some embodiments, the carbon-based material comprises at least one synthetic graphite and one natural graphite. Both the synthetic and natural graphite exhibit excellent conductivity, which reduces the heat generation of the negative electrode sheet 112 and improves the fast-charging performance of the battery cell 10.

[0234] In some embodiments, the negative electrode active material also comprises a silicon-based material. The introduction of the silicon-based material can increase the capacity of the negative electrode active material and the energy density of the battery cell 10.

[0235] In some embodiments, the mass fraction of the element silicon in the silicon-based material in the negative electrode active material is 0.3% to 10%, optionally 1% to 6%. For example, the mass fraction of the element silicon in the negative electrode active material is 0.3%, 0.5%, 0.8%, 1%, 1.2%, 1.5%, 1.8%, 2%, 2.2%, 2.5%, 2.8%, 3%, 3.2%, 3.5%, 3.8%, 4%, 4.2%, 4.5%, 4.8%, 5%, 5.2%, 5.5%, 5.8%, 6%, 6.2%, 6.5%, 6.8%, 7%, 7.2%, 7.5%, 7.8%, 8%, 8.2%, 8.5%, 8.8%, 9%, 9.2%, 9.5%, 9.8%, or 10%, or lies in a range consisting of any two of the above values.

[0236] By introducing the silicon-based material into the negative electrode sheet 112, both the capacity and the size of the negative electrode sheet 112 can be increased. Therefore, by limiting the mass fraction of the element silicon in the negative electrode active material to 0.3% to 10%, both the energy density and the size of the battery cell 10 can be ensured to a certain extent simultaneously, thereby reducing the deformation of the battery cell 10, lowering the risk of a connection failure between the battery cell and the bus component, and improving the cycle performance of the battery cell 10.

[0237] 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.

[0238] For example, the silicon-based material can be subjected to X-ray powder diffraction testing and qualitative analysis according to the general rule JIS / K0131-1996 for X-ray diffraction analysis on the negative electrode sheet or the negative electrode active material.

[0239] In some embodiments, the silicon-based material may comprise at least one of elemental silicon, silicon oxide, silicon-carbon composite, silicon-nitrogen composite, and silicon alloy material.

[0240] In some embodiments, the silicon-based material comprises at least one silicon oxide compound and a silicon-carbon composite.

[0241] In some embodiments, the negative electrode active material can comprise, in addition to the carbon-based material and optionally the silicon-based material, at least one tin-based material and lithium titanate. The tin-based material can comprise at least one elemental tin, tin oxide, and tin alloy.

[0242] In some embodiments of the present application, the negative electrode film layer 1122 comprises at least one film layer. In other words, the negative electrode film layer 1122 can use a single film layer or at least two film layers. Optionally, the negative electrode film layer 1122 comprises at least two film layers.

[0243] In the case where the negative electrode film layer 1122 comprises a single film layer, the negative electrode active material in the negative electrode film layer 1122 comprises a carbon-based material and optionally also a silicon-based material. In the case where a single film layer is present, the volume-averaged particle size Dv50 of the negative electrode active material is 8.2 µm to 13.5 µm. For example, the volume-averaged particle size Dv50 of the negative electrode active material is 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, 11.2 µm, 11.5 µm, 11.8 µm, 12 µm, 12.2 µm, 12.5 µm, 12.8 µm, 13 µm, 13.2 µm or 13.5 µm, or lies in a range consisting of any two of the above values.

[0244] In the case where the negative electrode film layer 1122 comprises at least two film layers, the negative electrode active material in the negative electrode film layer 1122 comprises a carbon-based material and optionally also a silicon-based material. The silicon-based material can be located in one or at least two of the at least two film layers. The negative electrode film layer 1122 can comprise two film layers, three film layers, four film layers, or even more film layers.

[0245] In some embodiments, the negative electrode film layer 1122 comprises a first negative electrode film layer 11221 and a second negative electrode film layer 11222, wherein the second negative electrode film layer 11222 is arranged between the first negative electrode film layer 11221 and the negative electrode current collector 1121. The negative electrode active material comprises a first negative electrode active material arranged in the first negative electrode film layer 11221 and a second negative electrode active material arranged in the second negative electrode film layer 11222, wherein the first negative electrode active material comprises synthetic graphite and the second negative electrode active material comprises one or more synthetic graphite, natural graphite, and silicon-based materials.

[0246] The interface between the first negative electrode film layer 11221 and the second negative electrode film layer 11222 is regular or irregular, optionally irregular.

[0247] The first negative electrode film layer 11221 and the second negative electrode film layer 11222 can be configured differently, thereby ensuring to some extent that both the extent and the capacity of the negative electrode film layer 1122 are simultaneously achieved; the double-layer coating makes it possible to build up the pore difference of the negative electrode film layer 1122, reduce the tortuosity of the ion transport, reduce the side reactions and improve the fast charging performance of the battery cell 10.

[0248] The artificial graphite can have a smaller volume-averaged particle size Dv50, which on the one hand shortens the solid-phase transport path of lithium ions and improves the fast charging performance; on the other hand, the material does not agglomerate as easily during the manufacturing process, which can improve the stability of the material.

[0249] In some embodiments, the ratio of the thickness of the first negative electrode film layer 11221 to the thickness of the second negative electrode film layer 11222 is 3:7 to 7:3. For example, the ratio of the thickness of the first negative electrode film layer 11221 to the thickness of the second negative electrode film layer 11222 is 3:7, 4:6, 5:5, 6:4 or 7:3.

[0250] Optionally, the ratio of the thickness of the first negative electrode film layer 11221 to the thickness of the second negative electrode film layer 11222 is 4:6 to 6:4.

[0251] By adjusting the ratio of the thickness of the first negative electrode film layer 11221 to the thickness of the second negative electrode film layer 11222, the gradient pore difference between the upper and lower layers can be further increased, the tortuosity of lithium ion transport reduced, and the fast-charging capability of the battery cell 10 improved.

[0252] In some embodiments, the thickness of the first negative electrode film layer 11221 is less than or equal to the thickness of the second negative electrode film layer 11222, which can further improve the fast charging capability of the battery cell 10.

[0253] In some embodiments, the first negative electrode active material is in granular form, and the second negative electrode active material is in granular form.

[0254] In some embodiments, the volume-averaged particle size Dv50 of the first negative electrode active material is less than or equal to the volume-averaged particle size Dv50 of the second negative electrode active material. Optionally, the volume-averaged particle size Dv50 of the first negative electrode active material is also smaller than the volume-averaged particle size Dv50 of the second negative electrode active material.

[0255] The particle size of the first and second negative electrode active materials differs, which can improve the fast-charging performance of the battery cell 10; during fast charging, the overpotential of the first negative electrode film layer 11221 is typically higher, and the bottleneck during fast charging is mainly in the first negative electrode film layer 11221. In the embodiments of the present application, the particle size of the first negative electrode active material is relatively small, which can shorten the solid-phase transport path of the ions, improve the fast-charging performance, and reduce the problem of ion deposition on the surface of the negative electrode sheet 112. The particle size of the second negative electrode active material is relatively large, which allows for the formation of larger pores in the second negative electrode film layer 11222.During charging, the pores can absorb the expansion, thereby reducing the amount of expansion of the negative electrode film layer 1122, reducing the force exerted by the battery cell 10 on the first bus component 30a and lowering the risk of a connection failure between the battery cell 10 and the first bus component 30a.

[0256] In some embodiments, the volume-averaged particle size Dv50 of the first negative electrode active material is 7.8 µm to 14.3 µm, optionally 7.8 µm to 11.3 µm. For example, the volume-averaged particle size Dv50 of the first negative electrode active 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 or 14.3 µm, or lies within a range consisting of any two of the above values.

[0257] If the volume-averaged particle size Dv50 of the first negative electrode active material is set to 7.8 µm to 14.3 µm, the solid-phase transport path of lithium ions can be shortened and the fast-charging performance improved; on the other hand, the material does not agglomerate as easily during the manufacturing process, which can improve the stability of the material; furthermore, the first negative electrode active material in the above volume-averaged particle size range can interact with the second negative electrode active material, which is advantageous for establishing a gradient pore difference between the first negative electrode film layer 11221 and the second negative electrode film layer 11222, reducing the tortuosity of lithium ion transport and improving the fast-charging performance of the battery cell 10.

[0258] The volume-averaged particle size Dv50 of the material refers to the particle size corresponding to 50% of the volume distribution, and the volume-averaged particle size Dv10 to the particle size corresponding to 10% of the volume distribution. The particle sizes 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 and Dv10 of the particles are measured using a Mastersizer 2000E laser particle size analyzer in accordance with test standard GB / T 19077-2016.

[0259] In some embodiments, the volume-averaged particle size Dv50 of the second negative electrode active material is 9.5 µm to 18.5 µm, optionally 9.5 µm to 14.6 µm.

[0260] For example, the volume-averaged particle size Dv50 of the negative electrode active material is 9.5 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 or 18.5 µm, or lies within a range consisting of any two of the above values.

[0261] If the volume-averaged particle size Dv50 of the second negative electrode active material is 9.5 µm to 18.5 µm, the pores of the second negative electrode film layer 11222 can become richer, which is advantageous for improving the fast-charging capability of the battery cell 10 and reduces the expansion of the negative electrode film layer 1122 during the charging process.

[0262] In some embodiments, the first negative electrode active material comprises graphite particles, and the volume-averaged particle size Dv50 of the graphite particles in the first negative electrode film layer 11221 is 7.8 µm to 14.3 µm, optionally 7.8 µm to 11.3 µm. Optionally, the first negative electrode active material comprises synthetic graphite.

[0263] The second negative electrode active material comprises graphite particles, and the volume-averaged particle size Dv50 of the graphite particles is 9.5 µm to 18.5 µm, optionally 9.5 µm to 14.6 µm. Optionally, the second negative electrode active material comprises natural graphite.

[0264] In some embodiments, the specific surface area of ​​the negative electrode active material is 0.5 m². 2 / g up to 3 m 2 / g, optional 0.6 m 2 / g up to 1.2 m 2 / g. For example, the specific surface area of ​​the negative electrode active material is 0.5 m².2 / g, 0.6 m 2 / g, 0.7 m 2 / g, 0.8 m 2 / g, 0.9 m 2 / g, 1.0 m 2 / g, 1.1 m 2 / g, 1.2 m 2 / g, 1.3 m 2 / g, 1.4 m 2 / g, 1.5 m 2 / g, 1.6 m 2 / g, 1.7 m 2 / g, 1.8 m 2 / g, 1.9 m 2 / g, 2.0 m 2 / g, 2.1 m 2 / g, 2.2 m 2 / g, 2.3 m 2 / g, 2.4 m 2 / g, 2.5 m 2 / g, 2.6 m 2 / g, 2.7 m 2 / g, 2.8 m 2 / g, 2.9 m 2 / g or 3.0 m 2 / g, or lies within a range consisting of any two of the above values.

[0265] The specific surface area of ​​the material has a well-known meaning in engineering and can be determined using devices and methods known in engineering, for example according to the test standard GB / T 19587-2017. In this process, the negative electrode active material is used as the sample and the specific surface area is measured using a specific surface and pore size analyzer (model: Tri-Star 3020) from the American manufacturer Micromeritics.

[0266] In the embodiments of the present application, the specific surface area of ​​the negative electrode active material can be limited to greater than or equal to 0.5 m². 2 / g the fast charging capability of the battery cell 10 is increased; by limiting the specific surface area of ​​the negative electrode active material to less than or equal to 3 m² 2 / g can reduce side reactions of the battery cell 10 during storage, slow down the expansion of the negative electrode sheet and reduce the expansion pressure.

[0267] In some embodiments, the compaction density of the positive electrode film layer 1112 at 100% SOC of the battery cell is 2.50 g / cm³. 3 up to 2.80 g / cm³ 3 , optional 2.55 g / cm² 3 up to 2.70 g / cm³ 3 . When battery cell 10 is at a state of charge (SOC) of 100%, the density of the positive electrode film layer 1112 is, for example, 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 , 2.72 g / cm³ 3 , 2.75 g / cm³ 3 , 2.78 g / cm³ 3 or 2.80 g / cm² 3, or lies within a range consisting of any two of the above values.

[0268] If the compaction density of the positive electrode film layer 1112 is within the above range, this is advantageous to increase the energy density of the battery cell 10; and because the positive electrode active material in the positive electrode film layer 1112 is relatively densely packed, and the contact resistance between the particles is low, the resistance of the positive electrode sheet 111 can be further reduced, thereby reducing heat generation during fast charging.

[0269] In the embodiments of the present application, the density of the positive electrode film layer 1112 at a state of charge (SOC) of 100% of the battery cell has the meaning known in the art. Here, the positive electrode sheet 111 is removed from the battery cell 10 at a state of charge (SOC) of 100%, and the density of the positive electrode film layer 1112 is measured. By way of example, the test method for the density of the positive electrode film layer 1112 can be the same as the test method for the density of the negative electrode film layer 1122.

[0270] In some embodiments, the one-sided coating weight of the positive electrode film layer is 1112,200 mg / 1540.25 mm². 2 up to 370 mg / 1540.25 mm 2 , optional 240 mg / 1540.25 mm 2 up to 330 mg / 1540.25 mm 2For example, the one-sided coating weight of the positive electrode film layer is 1112,200 mg / 1540.25 mm². 2 , 210 mg / 1540.25 mm 2 , 220 mg / 1540.25 mm 2 , 230 mg / l 540.25 mm 2 , 240 mg / 1540.25 mm 2 , 250 mg / 1540.25 mm 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 , 340 mg / 1540.25 mm 2 , 350 mg / 1540.25 mm 2 , 360 mg / 1540.25 mm 2 or 370 mg / 1540.25 mm 2 , or lies within a range consisting of any two of the above values.

[0271] In the embodiments of the present application, the one-sided coating weight of the positive electrode film layer 1112 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 negative electrode film layer 1122.

[0272] If the one-sided coating weight of the positive electrode film layer is 1112 to 200 mg / 1540.25 mm 2 up to 370 mg / 1540.25 mm 2 By determining the amount of heat generated per unit area of ​​the positive electrode sheet 111, it can be limited so that the increase in energy density and charging rate performance of the battery cell 10 can be ensured simultaneously.

[0273] In some embodiments, the porosity of the positive electrode sheet 111 is 25% to 32%. For example, the porosity of the positive electrode sheet 111 is 25%, 26%, 27%, 28%, 29%, 30%, 31%, or 32%, or lies in a range consisting of any two of the above values.

[0274] In the embodiments of the present application, the porosity of the positive electrode sheet 111 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 porosity of the negative electrode sheet 112.

[0275] A porosity of 25% or greater than or equal to the positive electrode sheet 111 can accommodate impurities resulting from side reactions of the positive electrode sheet 111, reduce the expansion pressure of the battery cell, decrease the deformation of the battery cell 10, improve the cycle performance of the battery cell 10, and lower the risk of a connection failure between the battery cell and the bus component. A porosity of 32% or less than or equal to the positive electrode sheet 111 can simultaneously ensure a certain degree of energy density of the battery cell 10.

[0276] In some embodiments, the thickness of the positive electrode sheet 111 is 0.13 mm to 0.2 mm. For example, the thickness of the positive electrode sheet 111 is 0.13 mm, 0.14 mm, 0.15 mm, 0.16 mm, 0.17 mm, 0.18 mm, 0.19 mm or 0.2 mm, or lies in a range consisting of any two of the above values.

[0277] In the embodiments of the present application, the thickness of the positive electrode sheet 111 has a known meaning in the art and can be determined using devices and methods known in the art. For example, the thickness of the positive electrode sheet 111 is measured with a high-precision micrometer.

[0278] By using the positive electrode sheet 111 with a lower thickness, the migration path of ions can be shortened, the migration rate of ions increased, the heat generation of the battery cell 10 reduced and the fast charging performance of the battery cell 10 improved.

[0279] In some embodiments, the ratio of the thickness of the positive electrode current collector 1111 to the thickness of the positive electrode film layer 1112 is 0.05 to 0.3. By way of example, in the embodiments of the present application, the thickness of the positive electrode film layer 1112 corresponds to the thickness of the positive electrode film layer 1112 located on one side of the positive electrode current collector 1111.

[0280] For example, the ratio of the thickness of the positive electrode current collector 1111 to the thickness of the positive electrode film layer 1112 is 0.05, 0.06, 0.07, 0.08, 0.09, 0.1, 0.12, 0.15, 0.18, 0.2, 0.22, 0.25, 0.28 or 0.3, or lies in a range consisting of any two of the above values.

[0281] By limiting the ratio of the thickness of the positive electrode current collector 1111 to the thickness of the positive electrode film layer 1112 to greater than or equal to 0.05, the current-carrying capacity of the positive electrode current collector 1111 can be increased, the temperature rise of the positive electrode sheet 111 reduced, and the fast-charging performance of the battery cell 10 improved; by limiting the ratio of the thickness of the positive electrode current collector 1111 to the thickness of the positive electrode film layer 1112 to less than or equal to 0.3, the capacity loss of the positive electrode sheet 111 can be reduced. In the embodiments of the present application, the ratio of the thickness of the positive electrode current collector 1111 to the thickness of the positive electrode film layer 1112 is limited to 0.05 to 0.3, thereby ensuring, to a certain extent, both the fast-charging capability and the energy density of the battery cell 10 simultaneously.

[0282] The thicknesses of the positive electrode film layer and the positive electrode current collector have meanings known in the art and can be determined using devices and methods known in the art. For example, the thickness of the positive electrode sheet is measured with a high-precision micrometer, the film layer is removed from the surface of the positive electrode current collector, and the thickness of the positive electrode current collector is measured with a high-precision micrometer. If the positive electrode film layer is coated on one side, its thickness is equal to the thickness of the positive electrode sheet minus the thickness of the positive electrode current collector. If the positive electrode film layer is coated on both sides, its thickness is equal to (thickness of the positive electrode sheet minus thickness of the positive electrode current collector) divided by 2.

[0283] In some embodiments, the thickness of the positive electrode current collector 1111 is 10 µm to 15 µm, optionally 12 µm to 15 µm. For example, the thickness of the positive electrode current collector 1111 is 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, or 15 µm, or lies within a range consisting of any two of the above values. When the thickness of the positive electrode current collector 1111 is within the above range, the positive electrode current collector 1111 exhibits excellent current conductivity and enables a higher energy density of the battery cell 10.

[0284] In some embodiments, part of the positive electrode current collector 1111 is not covered by the positive electrode film layer 1112; the part of the positive electrode current collector 1111 not covered by the positive electrode film layer 1112 can be used to form a positive electrode tab 11b.

[0285] In some embodiments, the positive electrode active material comprises a lithium-containing phosphate with an olivine structure or its modified material.

[0286] The lithium-containing phosphate with an olivine structure, or its modified material, can be a lithium-containing phosphate with an olivine structure or a material obtained by coating modification. For example, the lithium-containing phosphate with an olivine structure comprises phosphate particles and a coating layer, and the surface of the phosphate particle is coated with the ion-conducting layer, the ion-conducting layer comprising one or more of C, Fe, Ti, Zr, Hf, Ge, and Sn.

[0287] In some embodiments, the mass fraction of the lithium-containing phosphate with an olivine structure or its modified material in the positive electrode active material can be greater than or equal to 80% and less than or equal to 100%. The positive electrode active material in the present application can be considered a system of the lithium-containing phosphate with an olivine structure or its modified material system. If the mass fraction of the lithium-containing phosphate with an olivine structure or its modified material is less than 100%, the positive electrode active material can also comprise, but is not limited to, a commonly used positive electrode active material, for example, at least one of lithium-containing transition metal oxides.Examples of lithium-containing transition metal oxides 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.

[0288] Optionally, the mass fraction of the lithium-containing phosphate with olivine structure or its modified material in the positive electrode active material is 100%.

[0289] In some embodiments, the volume-averaged particle size of the positive electrode active material meets the conditions 1 µm ≤ Dv50 ≤ 2 µm and 0.4 µm ≤ Dv10 ≤ 0.7 µm.

[0290] For example, the Dv50 value of the positive electrode active material can be 1 µm, 1.1 µm, 1.15 µm, 1.2 µm, 1.25 µm, 1.3 µm, 1.35 µm, 1.4 µm, 1.45 µm, 1.5 µm, 1.55 µm, 1.6 µm, 1.65 µm, 1.7 µm, 1.75 µm, 1.8 µm, 1.85 µm, 1.9 µm, 1.95 µm or 2 µm, or be in a range consisting of any two of the above values.

[0291] For example, the Dv10 value of the positive electrode active material can be 0.4 µm, 0.45 µm, 0.5 µm, 0.55 µm, 0.6 µm, 0.65 µm or 0.7 µm, or in a range consisting of any two of the above values.

[0292] The particle size of the positive electrode active material is relatively small, which means that the deintercalation and intercalation path of lithium ions in the positive electrode active material is short and the amount of heat generated is low; furthermore, the particle size of the above positive electrode active material is not too small, which reduces agglomeration during the processing and manufacturing process, so that the performance of the positive electrode active material remains stable.

[0293] The volume-averaged particle size Dv50 of the material refers to the particle size corresponding to 50% of the volume distribution, and the volume-averaged particle size Dv10 to the particle size corresponding to 10% of the volume distribution. The particle sizes can be determined using devices and methods known in the art. For example, the positive electrode active material is used as a sample, and the Dv50 and Dv10 of the particles are measured using a Mastersizer 2000E laser particle size analyzer in accordance with test standard GB / T 19077-2016.

[0294] In some embodiments, the battery cell 10 comprises an electrolyte solution contained in the housing 12. During the charging and discharging process of the battery cell 10, the active ions migrate between the positive electrode sheet 111 and the negative electrode sheet 112 for intercalation and deintercalation, the electrolyte solution having the function of conducting the active ions between the positive electrode sheet 111 and the negative electrode sheet 112.

[0295] In some embodiments, the conductivity of the electrolyte solution at room temperature is 13 mS / cm to 20 mS / cm, optionally 15 mS / cm to 20 mS / cm. For example, the conductivity of the electrolyte solution at room temperature is 13 mS / cm, 13.5 mS / cm, 14 mS / cm, 14.5 mS / cm, 15 mS / cm, 15.5 mS / cm, 16 mS / cm, 16.5 mS / cm, 17 mS / cm, 17.5 mS / cm, 18 mS / cm, 18.5 mS / cm, 19 mS / cm, 19.5 mS / cm, or 20 mS / cm, or lies within a range consisting of any two of the above values.

[0296] For example, the room temperature could be 25 °C.

[0297] If the conductivity of the electrolyte solution is within the above range, the migration rate of ions in the electrolyte solution is relatively high, which can further reduce the internal resistance of battery cell 10, thereby reducing heat generation and thus improving the fast charging performance of battery cell 10.

[0298] The conductivity of the electrolyte solution refers to the ionic conductivity and can be determined using devices and methods known in the art, e.g. the test is carried out according to the industry standard HG-T 4067-2015.

[0299] In some embodiments, the density ρ of the electrolyte solution at room temperature fulfills the condition 1.05 g / mL≤ρ≤1.35 g / mL.

[0300] For example, the density ρ of the electrolyte solution is 1.05 g / mL, 1.10 g / mL, 1.15 g / mL, 1.2 g / mL, 1.25 g / mL, 1.3 g / mL or 1.35 g / mL, or lies in a range consisting of any two of the above values.

[0301] If the density ρ of the electrolyte solution is within the above range, the migration rate of lithium ions in the electrolyte solution is relatively high, which can further reduce the internal resistance of battery cell 10, thereby reducing heat generation and thus improving the fast charging performance of battery cell 10.

[0302] In the embodiments of the present application, the density of the electrolyte solution has a meaning known in the art and can be determined using devices and methods known in the art, for example by reference to GB / T 2013-2010 for testing.

[0303] In some embodiments, the electrolyte solution comprises an organic solvent, wherein the organic solvent comprises one or more carbonate solvents and carboxylic acid ester solvents.

[0304] In some embodiments, the carboxylic ester solvent comprises a chain-like carboxylic ester solvent, wherein the mass fraction of the chain-like carboxylic ester solvent in the organic solvent is 5% to 75%. For example, the mass fraction of the chain-like carboxylic ester solvent is 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, or 75%, or lies within any two of the above values. When the mass fraction of the chain-like carboxylic ester solvent is within the above-mentioned range, the viscosity of the electrolyte solution system is relatively low, which has a positive effect on the migration of lithium ions.

[0305] In some embodiments, the mass fraction of the chain-like carboxylic acid ester solvent in the organic solvent is 30% to 70%.

[0306] In some embodiments, the carboxylic acid ester comprises Ri-COO-R2, wherein R1 and R2 each independently comprise an alkyl group with 1 to 5 carbon atoms or a halogenated alkyl group with 1 to 5 carbon atoms. The above-mentioned 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 10.

[0307] In some embodiments, the carbonate solvent comprises one or more of ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate and ethyl methyl carbonate.

[0308] Optionally, the carbonate solvent may also include one or more of ethylene carbonate, dimethyl carbonate, and ethyl methyl carbonate.

[0309] The aforementioned carbonate solvent and chain-like carboxylic acid ester solvents are used together to improve the conductivity of the electrolyte solution, which has a positive effect on the migration of lithium ions.

[0310] Optionally, the mass fraction of the carbonate solvent in the organic solvent can be 5% to 95%, 25% to 60%, or 30% to 45%. For example, the mass fraction of the carbonate solvent in the organic solvent could be 25%, 26%, 27%, 28%, 29%, 30%, 31%, 32%, 33%, 34%, 35%, 36%, 37%, 38%, 40%, 45%, 48%, 50%, 55%, or 60%, or any combination of these values. The carbonate solvent with the mass fraction specified above can further improve the conductivity of the electrolyte solution, which has a positive effect on the migration of lithium ions.

[0311] For example, the carbonate solvent comprises one or more of ethylene carbonate, dimethyl carbonate and ethyl methyl carbonate, wherein the mass fraction of the carbonate solvent is 25% to 60%.

[0312] By combining the organic solvents, the conductivity of the electrolyte solution can be improved and the viscosity reduced, thereby increasing the fast charging performance of battery 2.

[0313] In some embodiments, the electrolyte solution comprises a lithium salt. The lithium salt comprises one or more fluorinated sulfonylimide salts and lithium hexafluorophosphate (LiPF6). The aforementioned lithium salt is readily dissociated, which promotes the rapid migration of lithium ions; furthermore, the electrolyte solution system is relatively stable and does not decompose easily, which can improve the cycle life of the battery cell 10.

[0314] Optionally, the fluorine-containing sulfonylimide salt comprises one or more of lithium bis(fluorosulfonyl)imide LiFSI and lithium bis(trifluoromethanesulfonyl)imide LiTFSI.

[0315] In some embodiments, the lithium salt comprises lithium bis(fluorosulfonyl)imide (LiFSI) and lithium hexafluorophosphate (LiPF6), wherein the molar concentration of lithium bis(fluorosulfonyl)imide (LiFSI) is 0.2 mol / L to 0.5 mol / L and the molar concentration of lithium hexafluorophosphate (LiPF6) is 0.5 mol / L to 1.0 mol / L. For example, the molar concentration of lithium bis(fluorosulfonyl)imide (LiFSI) is 0.4 mol / L to 0.5 mol / L and the molar concentration of lithium hexafluorophosphate (LiPF6) is 0.7 mol / L. For example, the molar concentration of lithium bis(fluorosulfonyl)imide (LiFSI) is 0.5 mol / L and the molar concentration of lithium hexafluorophosphate (LiPF6) is 0.5 mol / L. For example, the molar concentration of lithium bis(fluorosulfonyl)imide LiFSI is 0.2 mol / L and the molar concentration of lithium hexafluorophosphate LiPF6 is 0.8 mol / L.

[0316] Optionally, the ratio of the molar concentration of lithium bis(fluorosulfonyl)imide to the molar concentration of lithium hexafluorophosphate LiPF6 is (2 to 5):10. For example, the ratio of the molar concentration of lithium bis(fluorosulfonyl)imide to the molar concentration of lithium hexafluorophosphate LiPF6 is 2:10, 2.5:10, 3:10, 3.5:10, 4:10, 4.5:10 or 5:10, or lies in a range consisting of any two of the above values.

[0317] In some embodiments, the dimension of the electrode arrangement 11 along the thickness direction X is denoted by T, the thickness of the negative single-layer electrode sheet 112 by T1, and the number of layers of the negative electrode sheet 112 stacked in the thickness direction X by N. T, T1, and N satisfy the condition 0.3 ≤ (N × T1) / T ≤ 0.5.

[0318] The negative electrode sheet 112 comprises at least one straight layer 112a extending perpendicular to the thickness direction X, wherein straight layers 112a are provided in the electrode arrangement 11 N.

[0319] As an example, battery cell 10 is disassembled at a charge level of 0% and the electrode arrangement 11 is removed; T and T1 are measured using a high-precision micrometer.

[0320] For example, the electrode arrangement 11 has a wound structure, and the negative electrode sheet 112 comprises N straight layers 112a; alternatively, the electrode arrangement 11 has a stacked structure, and the electrode arrangement 11 comprises N negative electrode sheets 112, wherein the negative electrode sheets 112 each comprise a straight layer 112a.

[0321] During the cycle process of battery cell 10, the thickness of the negative electrode sheet 112 increases due to irreversible side reactions, leading to an expansion of battery cell 10. By limiting (N × T1) / T to 0.3 to 0.5, the expansion of battery cell 10 can be reduced, thus minimizing the risk of a connection failure between battery cell 10 and bus component 30.

[0322] In some embodiments, the limiting beam 21 is designed as a single-piece structure. This reduces weak connection points of the limiting beam 21, which contributes to increasing its structural strength and stiffness. Alternatively, the limiting beam 21 can also be assembled from several components; for example, it can be welded together from several sheet metal parts.

[0323] In some embodiments, the limiting beam 21 is a profile beam.

[0324] The boundary beam 21 can have a hollow beam structure, formed in one piece from a plate or rod by processes such as stamping / extrusion or metal casting. The wall thickness of the boundary beam 21 can range from 1 mm to 8 mm, depending on the actual requirements, with 3 mm to 5 mm being typical. At this wall thickness, the boundary beam 21 offers good value for money, as it can exhibit both low weight and good structural strength, thereby effectively suppressing the expansion deformation that occurs during the battery cell 10 cycle process.

[0325] The limiting beam 21 can be made of materials such as steel, iron, aluminum and aluminum alloys, but is not limited to these.

[0326] In some embodiments, the box body 20 comprises a frame body 22 and a support beam 23, wherein the frame body 22 defines a receiving space in which the boundary beams 21 and the multiple battery cells 10 are arranged. The support beam 23 is arranged on the side of the boundary beam 21 facing away from the multiple battery cells 10 and connects the frame body 22 and the boundary beam 21 to each other.

[0327] Optionally, the frame body 22 can be a rectangular frame body.

[0328] One or more support beams 23 may be provided.

[0329] Of two adjacent boundary beams 21, one boundary beam 21 can be connected to the support beam 23, or the two boundary beams 21 can each be connected to a support beam 23.

[0330] During the battery 2 cycle process, the limiting bar 21 serves to counteract the expansion force of the battery cells 10 during the cycle. The frame body 22 can support the limiting bar 21 by means of the support beams 23, thereby providing effective support for the limiting bar 21 and reducing its deformation. This, in turn, restricts the expansion of the battery cell 10 and increases its cycle life.

[0331] By providing the support force between the frame body 22 and the limiting beam 21, the overall structural strength and stiffness of the box body 20 can be improved and the risk of cracking of the box body 20 can be reduced.

[0332] In some embodiments, the frame body 22 comprises several side beams which are arranged and connected one after the other to form an annular frame body 22.

[0333] In some embodiments, the support beam 23 extends along the thickness direction X. Optionally, the cross-section of the support beam 23 can be rectangular, trapezoidal, elliptical, circular, L-shaped, or another form perpendicular to the thickness direction X.

[0334] In some embodiments, the support beam 23 is designed as a plate or as a hollow beam structure. The support beam 23 can be made of steel, aluminum, or aluminum alloys.

[0335] In some embodiments, the support beam 23 and the frame body 22 can be firmly connected to each other by welding, bolting or snapping.

[0336] In some embodiments, the limiting beam 21 extends along a direction perpendicular to the thickness direction X. The box body 20 comprises several support beams 23, which are spaced apart along the width direction Y of the limiting beam 21. The multiple support beams 23 can increase the confining force acting on the limiting beam 21, improve the uniformity of the load distribution in different areas of the limiting beam 21, reduce the deformation of the limiting beam 21 during the cycle process of the battery cell 10, and improve the cycle performance of the battery 2.

[0337] In some embodiments, the box body 20 also includes a support plate 24, wherein the multiple battery cells 10 and the limiting bars 21 are arranged on the same side of the support plate 24 and attached to the support plate 24. By way of example, the support plate 24 and the multiple battery cells 10 are arranged along the vertical direction Z of the battery cell 10.

[0338] In some embodiments, the box body 20 also includes a cover plate (not shown), wherein the cover plate and the support plate 24 are arranged opposite each other along the vertical direction Z and are attached to the frame body 22. The battery cell and the limiting bar are arranged between the cover plate and the support plate.

[0339] In some examples, the carrier plate 24 is located above the battery cell, with the battery cell arranged in reverse; alternatively, in other examples, the carrier plate 24 is located below the battery cell, with the battery cell arranged upright.

[0340] Fig. 13 is a schematic top view of a battery according to further embodiments of the present application; Fig. Figure 14 is an enlarged schematic view of the in Fig. 13 framed areas; Fig. Figure 15 is a schematic representation of the structure of a second bus component of Fig. 14.

[0341] With reference to Fig. 6, Fig. 13 to Fig.15 In some embodiments, the battery 2 further comprises at least one second bus component 30b, wherein the second bus component 30b has a single-layer structure and electrically connects at least two of the battery cells 10 together, and the thickness of the second bus component 30b is greater than the thickness of the first bus layer 31 and the thickness of the second bus component 30b is greater than the thickness of the second bus layer 32.

[0342] For example, among the several bus components 30, one part of the bus components 30 is the first bus component 30a and another part of the bus components 30 is the second bus component 30b.

[0343] In battery 2, the expansion of the battery cells 10 can vary at different locations. For battery cells 10 with lower expansion, a second bus component 30b with a single-layer structure can be used; compared to the first bus component 30a, the second bus component 30b has a simpler structure, is easier to manufacture, and can save costs. The thickness of the second bus component 30b is greater than the thickness of the first bus layer 31 and the thickness of the second bus layer 32, and its current-carrying capacity can meet the requirements.

[0344] In some embodiments, the sum of the thickness of the first bus layer 31 and the thickness of the second bus layer 32 is equal to the thickness of the second bus component 30b. In some embodiments of the present application, the difference in current-carrying capacity between the first bus component 30a and the second bus component 30b can be reduced and the current consistency improved.

[0345] In some embodiments, the second bus component 30b connects at least two of the battery cells 10, which are arranged along the thickness direction X.

[0346] In some embodiments, among the several battery cells 10, the battery cell 10 arranged at the outermost point along the thickness direction X is connected to the first bus component 30a.

[0347] During the charging process, the expansion of several battery cells 10 in the thickness direction X can overlap, leading to a significant displacement of the battery cell 10 located furthest along the thickness direction X. By using the first bus component 30a with a double-layer structure to connect the furthest battery cell 10, the risk of a connection failure between the first bus component 30a and the battery cell 10 can be reduced.

[0348] For example, the battery cell 10, arranged at the outermost point along the thickness direction X, is connected to the first bus layer 31.

[0349] In some embodiments, the battery cell 10 adjacent to the limiting bar 21 can be connected to the first bus component 30a.

[0350] In some embodiments, the multiple bus components 30 also include a third bus component 30c, wherein the third bus component 30c can connect two of the battery cells 10 that are adjacent along the width direction Y.

[0351] In some embodiments, in an external environment with a temperature of 25 °C to 35 °C, the charging time of battery cell 10 from 10% SOC to 80% SOC is 5 to 10.5 minutes. Optionally, in an external environment with a temperature of 25 °C to 35 °C, the charging time of battery cell 10 from 10% SOC to 80% SOC can be 5 to 10.5 minutes. For example, the charging time of battery cell 10 from 10% state of charge to 80% state of charge is 10.5 min, 10 min, 9.5 min, 9 min, 8.5 min, 8 min, 7.5 min, 7 min, 6.5 min, 6 min, 5.5 min, or 5 min, or lies within a range consisting of any two of the above values.

[0352] In the embodiments of the present application, the battery cell 10 has a fast-charging capability, which saves charging time.

[0353] In some embodiments, the charging steps of battery 2 or of any battery cell 10 of which battery 2 consists, from 10% to 80% can be carried out as follows: With a constant current of 5.0 C, charging from 10% SOC to 15% SOC is achieved; With a constant current of 5.0 C, charging from 15% SOC to 20% SOC is achieved; With a constant current of 5.0 C, charging from 20% SOC to 25% SOC is achieved; With a constant current of 5.0 C, charging from 25% SOC to 30% SOC is achieved; With a constant current of 5.0 C, charging from 30% SOC to 35% SOC is achieved; With a constant current of 5.0 C, charging from 35% SOC to 40% SOC is achieved; With a constant current of 4.6 C, it charges from 40% SOC to 45% SOC; With a constant current of 4.3 C, it charges from 45% SOC to 50% SOC; Charging with a constant current of 4.0 C from 50% SOC to 55% SOC; With a constant current of 3.7 C, it charges from 55% SOC to 60% SOC; With a constant current of 3.4 C, it charges from 60% SOC to 65% SOC; With a constant current of 3.1 C, it charges from 65% SOC to 70% SOC; With a constant current of 2.9 C, it charges from 70% SOC to 75% SOC; With a constant current of 2.7 C, the battery is charged from 75% SOC to 80% SOC.

[0354] As an example, the above charging strategy is carried out in an environment of 30 °C.

[0355] In some embodiments, the charging step of battery cell 10 from 0% SOC to 10% SOC can be carried out as follows: Charging from 0% SOC to 10% SOC is performed with a constant current of 5.0 C.

[0356] In some embodiments, the charging steps of battery cell 10 from 80% SOC to 98% SOC can be performed as follows: With a constant current of 1.8 C, charging from 80% SOC to 85% SOC is achieved; With a constant current of 1.3 C, it charges from 85% SOC to 90% SOC; With a constant current of 0.7 C, it charges from 90% SOC to 95% SOC; With a constant current of 0.33 C, charging from 95% SOC to 98% SOC is achieved.

[0357] In some embodiments, the charging step of battery cell 10 from 98% SOC to 100% SOC can be performed as follows: Charging from 98% SOC to 100% SOC is carried out with a constant current of 0.01 C, 0.05 C, 0.1 C, or 0.3 C. Alternatively, the charging step of battery cell 10 from 98% SOC to 100% SOC can be performed as follows: Charging from 98% SOC to 100% SOC is carried out with a constant current of 0.01 C, 0.05 C, or 0.1 C.

[0358] In some embodiments, the charging current during the charging process of battery cell 10 from 10% SOC to 80% SOC can be 2C to 6C, optionally 2.7C to 5C. During the charging process of battery cell 10, the charging current can change according to the SOC of battery cell 10.

[0359] In some embodiments, the battery cell 10 can be a lithium-ion battery cell. After the battery cell 10 has undergone 20 cycles according to the charging and discharging strategies, the negative electrode sheet of the battery cell 10 is disassembled, and the lithium plating area of ​​the negative electrode sheet is observed and measured. The ratio of the area of ​​the lithium plating area to the total area of ​​the negative electrode sheet is less than 2%.

[0360] As an example, the discharge strategy is carried out by discharging with a constant current from 0.33 C to 2.0 V.

[0361] For example, the charging strategy could be as follows: A constant current of 5.0 C charges the battery from 0% SOC to 5% SOC; With a constant current of 5.0 C, charging from 5% SOC to 10% SOC is achieved; With a constant current of 5.0 C, charging from 10% SOC to 15% SOC is achieved; With a constant current of 5.0 C, charging from 15% SOC to 20% SOC is achieved; With a constant current of 5.0 C, charging from 20% SOC to 25% SOC is achieved; With a constant current of 5.0 C, charging from 25% SOC to 30% SOC is achieved; With a constant current of 5.0 C, charging from 30% SOC to 35% SOC is achieved; With a constant current of 5.0 C, charging from 35% SOC to 40% SOC is achieved; With a constant current of 4.6 C, it charges from 40% SOC to 45% SOC; With a constant current of 4.3 C, it charges from 45% SOC to 50% SOC; Charging with a constant current of 4.0 C from 50% SOC to 55% SOC; With a constant current of 3.7 C, it charges from 55% SOC to 60% SOC; With a constant current of 3.4 C, it charges from 60% SOC to 65% SOC; With a constant current of 3.1 C, it charges from 65% SOC to 70% SOC; With a constant current of 2.9 C, it charges from 70% SOC to 75% SOC; With a constant current of 2.7 C, it charges from 75% SOC to 80% SOC; With a constant current of 1.8 C, it charges from 80% SOC to 85% SOC; With a constant current of 1.3 C, it charges from 85% SOC to 90% SOC; With a constant current of 0.7 C, it charges from 90% SOC to 95% SOC; With a constant current of 0.33 C, it charges from 95% SOC to 98% SOC; With a constant current of 0.1 C, it charges from 98% SOC to 100% SOC.

[0362] The battery cell 10 according to the embodiments of the present application can be charged from 10% SOC to 80% SOC in 10.5 minutes without lithium plating or with only minor lithium plating, and exhibits good fast-charging capability. For example, a ratio of the area of ​​the lithium plating area to the total area of ​​the negative electrode sheet of less than 0.05% can be considered no lithium plating, and a ratio of the area of ​​the lithium plating area to the total area of ​​the negative electrode sheet of less than 2% and greater than or equal to 0.05% can be considered minor lithium plating.

[0363] According to some embodiments of the present application, the present application further provides a power-consuming device comprising a battery 2 according to one of the above embodiments, wherein the battery 2 serves to supply power to the power-consuming device. The power-consuming device may be one of the aforementioned devices or systems that uses the battery 2.

[0364] With reference to Fig. Figures 2 to 12 describe embodiments of the present application providing a battery 2 comprising several battery cells 10, a housing 20, and several bus components 30. Several battery cells 10 are accommodated in the housing 20.

[0365] The battery cell 10 comprises a housing 12 and an electrode arrangement 11 contained within the housing 12. The expansion pressure of the battery cell in the thickness direction X is 0.5 MPa to 2.4 MPa.

[0366] The electrode arrangement 11 comprises a positive electrode sheet 111, a negative electrode sheet 112, and a separator 113, wherein the separator 113 separates the positive electrode sheet 111 and the negative electrode sheet 112. Optionally, the positive electrode sheet 111, the negative electrode sheet 112, and the separator 113 are arranged in a coiled configuration.

[0367] The negative electrode sheet 112 comprises a negative electrode current collector 1121 and a negative electrode film layer 1122 arranged on at least one side of the negative electrode current collector 1121, wherein the negative electrode film layer 1122 comprises a negative electrode active material. The porosity of the negative electrode sheet 112 is 27% to 40%. The compaction density of the negative electrode film layer 1122 at 100% state of charge (SOC) of the battery cell is 1.15 g / cm³. 3 up to 1.36 g / cm³ 3 .

[0368] The negative electrode film layer 1122 comprises a first negative electrode film layer 11221 and a second negative electrode film layer 11222, wherein the second negative electrode film layer 11222 is arranged between the first negative electrode film layer 11221 and the negative electrode current collector 1121. The negative electrode active material comprises a first negative electrode active material arranged in the first negative electrode film layer 11221 and a second negative electrode active material arranged in the second negative electrode film layer 11222, wherein the first negative electrode active material comprises synthetic graphite and the second negative electrode active material comprises one or more synthetic graphite, natural graphite and silicon-based material.The volume-averaged particle size Dv50 of the first negative electrode active material is less than or equal to the volume-averaged particle size Dv50 of the second negative electrode active material.

[0369] The positive electrode sheet 111 comprises a positive electrode current collector 1111 and a positive electrode film layer 1112 arranged on at least one side of the positive electrode current collector 1111. The density of the positive electrode film layer 1112 at 100% state of charge (SOC) of the battery cell is 2.50 g / cm³. 3 up to 2.80 g / cm³ 3The porosity of the positive electrode sheet 111 is 25% to 32%. The ratio of the thickness of the positive electrode current collector 1111 to the thickness of the positive electrode film layer 1112 is 0.05 to 0.3. The positive electrode active material comprises a lithium-containing phosphate with an olivine structure or a modified version thereof. The volume-averaged particle size of the positive electrode active material meets the conditions 1 µm ≤ Dv50 ≤ 2 µm and 0.4 µm ≤ Dv10 ≤ 0.7 µm.

[0370] The box body 20 comprises two boundary beams 21, the two boundary beams 21 being spaced apart along the thickness direction X of the battery cell 10. The multiple battery cells 10 are arranged in an array and form multiple battery cell rows 100. The multiple battery cell rows 100 are arranged along the width direction Y of the boundary beam 21. Each battery cell row 100 comprises at least two of the battery cells 10, which are arranged along the thickness direction X of the battery cell 10. Multiple battery cells 10 are arranged between the two boundary beams 21.

[0371] The box body 20 comprises a frame body 22 and a support beam 23, wherein the frame body 22 defines a receiving space in which the boundary beams 21 and the multiple battery cells 10 are arranged. The support beam 23 is arranged on the side of the boundary beam 21 facing away from the multiple battery cells 10 and connects the frame body 22 and the boundary beam 21 to each other. The confining element 40 connects adjacent boundary beams 21 to each other and is bonded to the battery cell 10.

[0372] The multiple bus components 30 electrically connect the multiple battery cells 10 to one another. The multiple bus components 30 comprise at least one first bus component 30a, wherein the first bus component 30a comprises a first bus layer 31 and a second bus layer 32, which are stacked on top of each other and connected to one another, wherein the first bus layer 31 connects at least two of the battery cells 10, which are arranged in the thickness direction X. Example of implementation

[0373] 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

[0374] The positive electrode sheet comprised a positive electrode current collector and positive electrode film layers arranged on both sides of the positive electrode current collector, the positive electrode current collector being an aluminum foil with a thickness of 15 µm.

[0375] The positive electrode film layer comprised a film layer formed by uniformly applying the positive electrode paste (solvent: N-methyl-2-pyrrolidone, NMP) to the surface of the conductive layer of the positive electrode, drying, and cold pressing. The positive electrode film layer comprised a positive electrode active material, a binder (polyvinylidene fluoride, PVDF), and a conductive agent (acetylene carbon black) in a weight ratio of 97:2:1.

[0376] The positive electrode active material comprised lithium iron phosphate and an ion-conducting layer, wherein the surface of the lithium iron phosphate was coated with the ion-conducting layer, which comprised lithium iron titanium phosphate (Li₂FeTi(PO₄)₃) and amorphous carbon. The Dv₅₀ value of the positive electrode active material was 1.6 µm and the Dv₁₀ value was 0.64 µm.

[0377] The one-sided coating weight of the positive electrode film layer was 0.21 g / 1540.25 mm². 2 The compaction density of the positive electrode film layer after cold pressing was 2.6 g / cm³. 3 . 2. Production of the negative electrode sheet

[0378] The negative electrode sheet comprised a negative electrode current collector and negative electrode film layers arranged on both sides of the negative electrode current collector, the negative electrode current collector being a copper foil with a thickness of 6 µm.

[0379] The negative electrode film layer comprised a film layer formed by uniformly applying the negative electrode paste (solvent: deionized water) to the surface of the conductive layer of the negative electrode, followed by drying and cold pressing.

[0380] The one-sided coating weight of the negative electrode film layer is 0.096 g / 1540.25 mm². 2 The compaction density of the negative electrode film layer after cold pressing is 1.6 g / cm³. 3 .

[0381] The negative electrode film layer comprised a first negative electrode film layer and a second negative electrode film layer, with the second negative electrode film layer being located between the first negative electrode film layer and the negative electrode current collector.

[0382] The second negative electrode film layer comprised graphite particles, a conductive agent acetylene carbon black, a second lithium-containing binder (a copolymer of lithium acrylate-acrylonitrile-acrylamide-hydroxyethyl acrylate, wherein the molar ratio of lithium acrylate monomer, acrylonitrile monomer, acrylamide monomer and hydroxyethyl acrylate monomer was 35%:30%:15%:20%), a negative electrode binder styrene-butadiene rubber and a thickening agent sodium carboxymethylcellulose with a mass ratio of 96.5:0.5:0.5:1.5:1. The mass fraction of the element lithium in the second lithium-containing binder was 4.8%, the Dv50 value of the graphite particles was 11.3 µm, the graphite particles each comprised an artificial graphite and a carbon coating layer, the surface of the artificial graphite was coated with the carbon coating layer, and the mass fraction of the carbon coating layer was 3.5%.

[0383] The first negative electrode film layer comprised graphite particles, a conductive agent acetylene carbon black, a first lithium-containing binder (a copolymer of lithium acrylate-acrylonitrile-acrylamide-hydroxyethyl acrylate, wherein the molar ratio of lithium acrylate monomer, acrylonitrile monomer, acrylamide monomer and hydroxyethyl acrylate monomer was 35%:30%:15%:20%), a negative electrode binder styrene-butadiene rubber and a thickening agent sodium carboxymethylcellulose with a mass ratio of 97.5:0.5:0.5:0.5:1. The mass fraction of the element lithium in the first lithium-containing binder was 4.8%, the Dv50 value of the graphite particles was 11.3 µm, the graphite particles each comprised an artificial graphite and a carbon coating layer, the surface of the artificial graphite was coated with the carbon coating layer, and the mass fraction of the carbon coating layer was 3.5%. 3. Separator

[0384] 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

[0385] The electrolyte solution comprised an organic solvent, a lithium salt, and an additive.

[0386] The organic solvent comprised a chain-like carboxylic acid ester solvent (ethyl acetate) with a mass fraction of 60% and a carbonate solvent with a mass fraction of 40% (30% ethylene carbonate EC, the remainder dimethyl carbonate), whereby the mass fractions of the individual components in the organic solvent were calculated based on the mass of the organic solvent.

[0387] Based on the mass of the electrolyte solution, the mass fraction of the additive was 6.5%, comprising vinylene carbonate VC, fluoroethylene carbonate FEC, ethylene sulfite ES and lithium difluoro(oxalato)borate LiDFOB in a mass ratio of 5:0.5:0.5:0.5.

[0388] The lithium salt comprised 1 mol / L lithium hexafluorophosphate LiPF6.

[0389] The conductivity of the electrolyte solution at room temperature was 16.4 mS / cm. 5. Manufacturing the battery cell

[0390] The above positive electrode sheet, the above separator and the above negative electrode sheet were stacked in sequence, the separator was placed between the positive electrode sheet and the negative electrode sheet to fulfill an insulating function in order to obtain an electrode assembly; the electrode assembly was placed in the housing, after drying the electrolyte solution was injected and a battery cell was obtained by vacuum sealing, standing, formation and shaping, etc. (6) Battery production

[0391] The manufactured battery cells were installed in a box-like housing. Subsequently, several bus components were welded to the electrode connections of the battery cells, and the high- and low-voltage wiring harnesses were installed to complete the battery.

[0392] The bus components in question could be those in Fig.Figure 6 shows the first bus component. The first bus component had a double-layer structure. The thickness Th of the single-layer structure of the first bus component was 1.5 mm, i.e., the thickness of the first bus layer was 1.5 mm and the thickness of the second bus layer was 1.5 mm. Example 2

[0393] The battery cell and the battery were manufactured using a similar process to that described in embodiment 1. The difference from embodiment 1 was that the one-sided coating weight of the positive electrode film layer, the compaction density of the positive electrode film layer after cold pressing, the one-sided coating weight of the negative electrode film layer, and the compaction density of the negative electrode film layer after cold pressing were adjusted. Example 3

[0394] The battery cell and the battery were manufactured using a similar process to that described in embodiment 1. The difference from embodiment 1 was that the one-sided coating weight of the positive electrode film layer, the compaction density of the positive electrode film layer after cold pressing, the one-sided coating weight of the negative electrode film layer, and the compaction density of the negative electrode film layer after cold pressing were adjusted. Example 4

[0395] The battery cell and the battery were manufactured using a similar process to that described in embodiment 1. The difference from embodiment 1 was that the one-sided coating weight of the positive electrode film layer, the compaction density of the positive electrode film layer after cold pressing, the one-sided coating weight of the negative electrode film layer, the compaction density of the negative electrode film layer after cold pressing, and the thickness Th of the single-layer structure of the first bus component were adapted. Example 5

[0396] The battery cell and the battery were manufactured using a similar process to that described in embodiment 1. The difference from embodiment 1 was that the one-sided coating weight of the positive electrode film layer, the compaction density of the positive electrode film layer after cold pressing, the one-sided coating weight of the negative electrode film layer, the compaction density of the negative electrode film layer after cold pressing, and the thickness Th of the single-layer structure of the first bus component were adapted. Example 6

[0397] The battery cell and the battery were manufactured using a similar process to that described in embodiment 1. The difference from embodiment 1 was that the one-sided coating weight of the positive electrode film layer, the compaction density of the positive electrode film layer after cold pressing, the one-sided coating weight of the negative electrode film layer, the compaction density of the negative electrode film layer after cold pressing, and the thickness Th of the single-layer structure of the first bus component were adapted. Example 7

[0398] The battery cell and the battery were manufactured using a similar process to that described in embodiment 1. The difference from embodiment 1 was that the one-sided coating weight of the positive electrode film layer, the compaction density of the positive electrode film layer after cold pressing, the one-sided coating weight of the negative electrode film layer, the compaction density of the negative electrode film layer after cold pressing, and the thickness Th of the single-layer structure of the first bus component were adapted. Comparative example 1

[0399] The battery cell and the battery were prepared using a similar process to that described in embodiment 1. The difference from embodiment 1 was that the one-sided coating weight of the positive electrode film layer, the one-sided coating weight of the negative electrode film layer, and the compaction density of the negative electrode film layer were adjusted after cold pressing. Comparative example 2

[0400] The battery cell and the battery were manufactured using a similar process to that described in embodiment 1. The difference from embodiment 1 was that the one-sided coating weight of the positive electrode film layer, the compaction density of the positive electrode film layer after cold pressing, the one-sided coating weight of the negative electrode film layer, the compaction density of the negative electrode film layer after cold pressing, and the thickness Th of the single-layer structure of the first bus component were adapted. Comparative example 3

[0401] The battery cell and the battery were manufactured using a similar process to that described in embodiment 1. The difference from embodiment 1 was that the one-sided coating weight of the positive electrode film layer, the compaction density of the positive electrode film layer after cold pressing, the one-sided coating weight of the negative electrode film layer, the compaction density of the negative electrode film layer after cold pressing, and the thickness Th of the single-layer structure of the first bus component were adapted. Comparative example 4

[0402] The battery cell and the battery were manufactured using a similar process to that described in embodiment 1. The difference from embodiment 1 was that the one-sided coating weight of the positive electrode film layer, the compaction density of the positive electrode film layer after cold pressing, the one-sided coating weight of the negative electrode film layer, the compaction density of the negative electrode film layer after cold pressing, and the thickness Th of the single-layer structure of the first bus component were adapted. Performance tests: 1. Test of the expansion pressure of the battery cell:

[0403] At an ambient temperature of 45 °C, a battery cell manufactured above was discharged to 2.0 V at a constant discharge rate of 1 C;

[0404] The battery cell was clamped between two clamping plates, with each clamping plate located on one of the two sides of the battery cell along the thickness direction and covering the main surface; At an ambient temperature of 45 °C, the battery cell was charged to 3.8 V at a constant charging rate of 0.8 C, and the pressure exerted by the battery cell on the terminal plates was detected and recorded; According to the above charging and discharging strategy, the battery cell was cyclically charged and discharged until the battery cell was degraded to 70% SOH (i.e., the discharge capacity of the battery cell was degraded to 70% of the nominal capacity of the battery cell), and the maximum pressure exerted by the battery cell on the terminal plates was recorded; The expansion pressure Q of the battery cell in the thickness direction was calculated as: maximum pressure / area of ​​the large surface. 2. Test of volume energy density:

[0405] The discharge energy of the first cycle was tested according to the following steps: At 25 °C, the battery cell manufactured above was charged to 3.8 V with a constant current of 0.33 C and then discharged to 2.0 V with a constant current of 0.33 C. The discharge energy A0 at this time was recorded in Wh.

[0406] Battery cell volume: The length, width, and height of the battery cell were measured using calipers (generally based on the battery cell casing size, excluding the height of the electrode terminals and the insulating film outside the casing). The battery cell volume V0 was calculated in units of L.

[0407] The volume energy density of the battery cell VED = A0 / V0 in the unit Wh / L. 3. Cycle performance test I:

[0408] At an ambient temperature of 45 °C, the above-constructed battery was discharged, with the battery cell being discharged to 2.0 V at a constant discharge rate of 1 C; The above-mentioned battery was charged at an ambient temperature of 45 °C, with the battery cell being charged to 3.8V at a constant charging rate of 0.8 C; According to the above charging and discharging strategy, the battery was cyclically charged and discharged until the battery was degraded to 70% SOH (discharge capacity of the battery cell / nominal capacity of the battery cell = 70%). During the cycle process, the maximum temperature of the end cap of the battery cell housing was measured, and it was observed whether the weld between the first bus component and the electrode connection showed any cracks. 4. Cycle performance test II:

[0409] At an ambient temperature of 30 °C, the above-constructed battery was discharged, with the battery cell being discharged to 2.0 V at a constant discharge rate of 0.33 C; The following charging strategy was used at an ambient temperature of 30 °C: A constant current of 5.0 C charges the battery from 0% SOC to 5% SOC; With a constant current of 5.0 C, charging from 5% SOC to 10% SOC is achieved; With a constant current of 5.0 C, charging from 10% SOC to 15% SOC is achieved; With a constant current of 5.0 C, charging from 15% SOC to 20% SOC is achieved; With a constant current of 5.0 C, charging from 20% SOC to 25% SOC is achieved; With a constant current of 5.0 C, charging from 25% SOC to 30% SOC is achieved; With a constant current of 5.0 C, charging from 30% SOC to 35% SOC is achieved; With a constant current of 5.0 C, charging from 35% SOC to 40% SOC is achieved; With a constant current of 4.6 C, it charges from 40% SOC to 45% SOC; With a constant current of 4.3 C, it charges from 45% SOC to 50% SOC; Charging with a constant current of 4.0 C from 50% SOC to 55% SOC; With a constant current of 3.7 C, it charges from 55% SOC to 60% SOC; With a constant current of 3.4 C, it charges from 60% SOC to 65% SOC; With a constant current of 3.1 C, it charges from 65% SOC to 70% SOC; With a constant current of 2.9 C, it charges from 70% SOC to 75% SOC; With a constant current of 2.7 C, it charges from 75% SOC to 80% SOC; With a constant current of 1.8 C, it charges from 80% SOC to 85% SOC; With a constant current of 1.3 C, it charges from 85% SOC to 90% SOC; With a constant current of 0.7 C, it charges from 90% SOC to 95% SOC; With a constant current of 0.33 C, it charges from 95% SOC to 98% SOC; With a constant current of 0.1 C, it charges from 98% SOC to 100% SOC.

[0410] According to the above charging and discharging strategy, the battery was cyclically charged and discharged until the battery was degraded to 70% SOH; During the cycle process, the maximum temperature of the end cap of the battery cell housing was measured, and it was observed whether the weld between the first bus component and the electrode connection showed any cracks.

[0411] It should be explained here that cycle performance test I and cycle performance test II were each carried out with one of two batteries manufactured using the same reconditioning method.

[0412] The test results for embodiments 1 to 7 and comparison examples 1 to 4 are listed in Table 1. Table 1 Cycle performance test I Cycle performance test II One-sided coating weight of the positive electrode film layer (g / 1540.25 mm²) 2 ) One-sided coating weight of the negative electrode film layer (g / 1540.25 mm²) 2 ) Compaction density of the positive electrode film layer after cold pressing (g / cm²) 3 ) Compaction density of the negative electrode film layer after cold pressing (g / cm³) 3 ) Expansion pressure Q(MPa) Thickness of single-layer structure (mm) Volume energy densityVED (Wb / L) Maximum temperature of the end cap (°C) Cracking at the weld bead between electrode connection and understem bus component Maximum temperature of the end cap (°C) Cracking at the weld bead between electrode connection and understem bus component Example 1 0,21 0,096 2,6 1,6 0,5 1,5 390 <80 No <80 No Example of implementation 9 0.29 0,131 2,63 1,63 1,5 1,5 405 <80 No <80 No Example 2, Example 3 0,34 0.155 2,65 1,63 2,4 1,5 415 <80 No <80 No Example 4 0,34 0,155 2,65 1,63 2,4 1 415 <80 No <80 No Example 5 0,29 0,131 2,63 1,63 1,5 1,2 405 <80 No <80 No Example 6 0,29 0,131 2,63 1,63 1,5 1,8 405 <80 No <80 No Example 7 0.29 0,131 2.63 1,63 1,5 2,5 405 <80 No <80 No Comparative example 1 0,18 0,080 2,6 1,58 0,3 1,5 380 <80 No <80 No DS comparison example 2 0.34 0.155 2.65 1.63 2.4 3 415 <80 Yes <80 Yes Comparative example 3 0.31 0.140 2.70 1.65 2.7 2.5 430 <80 Yes <80 Yes Comparative example 4 0.29 0.131 2.63 1.63 1.5 0.5 405 >80 No >80 No

[0413] As can be seen from comparative example 1 in Table 1, the one-sided coating weight of the positive electrode film layer, the compaction density of the positive electrode film layer after cold pressing, the one-sided coating weight of the negative electrode film layer, and the compaction density of the negative electrode film layer after cold pressing are relatively low. Although the battery cell exhibits low expansion pressure and the weld bead between the electrode terminal and the first bus component does not easily tear during the cycle process, the volume energy density of the battery cell is relatively low.

[0414] Referring to embodiments 1 to 7 and comparative example 1, the volume energy density of the battery cell in the embodiments of the present application could be increased to or greater than 390 Wh / L by increasing the one-sided coating weight of the positive electrode film layer, the compaction density of the positive electrode film layer after cold pressing, the one-sided coating weight of the negative electrode film layer, and the compaction density of the negative electrode film layer after cold pressing. Although the expansion pressure of the battery cell is not less than 0.5 MPa, the risk of weld cracking due to the increased expansion pressure can be reduced and the reliability of the battery increased by combining it with the first bus component with a double-layer structure.The first bus component has a double-layered structure and high current conductivity, which reduces the heat development of the first bus component during the cycle process, which in turn reduces the heat conducted to the end cover and electrode assembly, reduces the temperature rise of the battery cell and improves the cycle performance of the battery.

[0415] With reference to embodiments 1 to 7 and comparative examples 2 to 3, in the embodiments of the present application, by adjusting parameters such as the one-sided coating weight of the positive electrode film layer, the compaction density of the positive electrode film layer after cold pressing, the one-sided coating weight of the negative electrode film layer and the compaction density of the negative electrode film layer after cold pressing, the expansion pressure of the battery cell can be limited to no more than 2.4 MPa and the volume energy density of the battery cell can be achieved at 415 Wh / L.

[0416] By adjusting the thickness of the single-layer structure of the first bus component, the current-carrying capacity and deformation capacity of the first bus component can be balanced. If the expansion pressure of the battery cell is between 0.5 MPa and 2.4 MPa and the thickness of the single-layer structure of the first bus component is limited to a maximum of 2.5 mm, the risk of weld failure between the electrode terminal and the first bus component can be reduced, and the heat generation of the first bus component during the cycling process can be reduced. This, in turn, reduces the heat conducted to the end cap and electrode assembly, lowers the temperature rise of the battery cell, and improves the battery's cycle performance.

[0417] Referring to embodiments 1 to 7 and comparative example 4, the current-carrying capacity and deformation capacity of the first bus component can be balanced by adjusting the thickness of the single-layer structure of the first bus component. In the embodiments of the present application, the thickness of the single-layer structure of the first bus component is limited to at least 1 mm, which improves the current-carrying capacity and reduces the heat generation of the first bus component during the cycling process at a battery cell expansion pressure between 0.5 MPa and 2.4 MPa. This, in turn, reduces the heat conducted to the end cap and the electrode assembly, lowers the temperature rise of the battery cell, and improves the cycle performance of the battery.

[0418] Referring to embodiments 1 to 7 in Table 1, the embodiments of the present application enable the heat generation of the first bus component to be reduced and the expansion of the battery cell to be reduced during the fast charging process of the battery in order to decrease the risk of battery failure. The battery cell of the present application has a fast-charging capability, and the charging time of the battery cell from 10% SOC to 80% SOC is 5 to 10.5 minutes.

[0419] It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other, provided there is no conflict.

[0420] Finally, it should be noted that the foregoing embodiments serve only to illustrate the technical solutions of the present application and not to limit them; although the present application has been described in detail with reference to the foregoing embodiments, it should be obvious to a person skilled in the art that he may further modify the technical solutions described in the aforementioned embodiments or replace some of their technical features with equivalent features; and such modifications or replacements, however, do not result in the essence of the corresponding technical solutions deviating from the spirit and scope of the technical solutions 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] JIS / K0131-1996

[0238] GB / T 19077-2016 [0258, 0293] GB / T 19587-2017

[0265] GB / T 2013-2010

[0302]

Claims

[1] Battery, comprising: several battery cells arranged along the thickness direction of the battery cells, the battery cell comprising a housing and an electrode arrangement received in the housing, wherein the expansion pressure of the battery cell in the thickness direction is 0.5 MPa to 2.4 MPa; and a first bus component that electrically connects at least two of the battery cells arranged along the thickness direction, wherein the first bus component has a multilayer structure, wherein the electrode arrangement comprises a positive electrode sheet, a negative electrode sheet and a separator arranged between the positive and negative electrode sheets, wherein the positive electrode sheet comprises a positive electrode current collector and a positive electrode film layer arranged on at least one side of the positive electrode current collector, wherein the positive electrode film layer comprises a positive electrode active material, wherein the positive electrode active material comprises a lithium-containing phosphate with an olivine structure, wherein the negative electrode sheet comprises a negative electrode current collector and a negative electrode film layer arranged on at least one side of the negative electrode current collector, wherein the negative electrode film layer comprises a negative electrode active material, wherein the negative electrode active material comprises a carbon-based material. [2] Battery according to claim 1, wherein the first bus component comprises a first bus layer and a second bus layer stacked on top of each other and connected to each other, wherein the first bus layer connects at least two of the battery cells arranged along the thickness direction. [3] Battery according to claim 2, wherein the battery cell comprises an electrode terminal arranged on the housing, wherein the electrode terminal is electrically connected to the electrode arrangement; wherein the part of the first bus layer that does not overlap with the second bus layer is connected to the electrode terminal. [4] Battery according to claim 3, wherein the first bus layer is welded to the electrode terminal, and a weld area between the first bus layer and the electrode terminal is greater than or equal to 60 mm. 2 is. [5] Battery according to one of claims 2 to 4, wherein the first bus component comprises at least one bending section, the bending section connecting the first bus layer and the second bus layer. [6] Battery according to claim 5, wherein the first bus layer comprises a first bus section, a second bus section and a first buffer section, wherein the first bus section and the second bus section are arranged along the thickness direction and are connected to different battery cells, and the first buffer section connects the first bus section and the second bus section to each other; wherein at least one of the first bus section and the second bus section is connected to the bending section. [7] Battery according to claim 6, wherein the bending section is arranged such that it bypasses the first buffer section. [8] Battery according to claim 6 or 7, wherein the second bus layer comprises a first stacking section, a second stacking section and a second buffer section, wherein the first stacking section is stacked with the first bus section and connected by at least one bending section, and the second stacking section is stacked with the second bus section and connected by at least one bending section, wherein the second buffer section connects the first stacking section and the second stacking section to each other; wherein the second buffer section overlaps at least partially with the first buffer section in the stacking direction of the first bus layer and the second bus layer. [9] Battery according to claim 8, wherein the second buffer section is arranged adjacent to the first buffer section. [10] Battery according to one of claims 2 to 9, wherein the battery further comprises at least one second bus component, wherein the second bus component has a single-layer structure and electrically connects at least two of the battery cells together, and the thickness of the second bus component is greater than the thickness of the first bus layer and the thickness of the second bus component is greater than the thickness of the second bus layer. [11] Battery according to claim 10, wherein the sum of the thickness of the first bus layer and the thickness of the second bus layer is equal to the thickness of the second bus component. [12] Battery according to any one of claims 2 to 11, wherein the thickness of the first bus layer is 1 mm to 2.5 mm; and / or wherein the thickness of the second bus layer is 1 mm to 2.5 mm. [13] Battery according to any one of claims 2 to 12, wherein the volume energy density of the battery cell is 390 Wh / L to 450 Wh / L and the thickness of the first bus layer is less than or equal to 2.5 mm; or wherein the volume energy density of the battery cell is 450 Wh / L to 480 Wh / L and the thickness of the first bus layer is less than or equal to 2.2 mm. [14] Battery according to any one of claims 2 to 13, wherein the negative electrode active material also comprises a silicon-based material; wherein the mass fraction of the element silicon in the silicon-based material in the negative electrode active material is 1% to 6%; wherein the thickness of the first bus layer is 1.2 mm to 2.2 mm and the thickness of the second bus layer is 1.2 mm to 2.2 mm. [15] Battery according to any one of claims 2 to 14, wherein the first bus layer comprises a first bus section, a second bus section and a first buffer section for connecting the first and second bus sections together, wherein the first bus section and the second bus section are arranged along the thickness direction and are connected to different battery cells; wherein the first buffer section projects beyond the first bus section and the second bus section in the stacking direction of the first bus layer and the second bus layer; wherein a recess is provided at the position of the first bus layer corresponding to the first buffer section. [16] Battery according to claim 15, wherein the volume energy density of the battery cell is 390 Wh / L to 450 Wh / L and the depth of the recess is 1.2 mm to 2.5 mm; or where the volume energy density of the battery cell is 450 Wh / L to 480 Wh / L and the depth of the depression is 1 mm to 2.2 mm. [17] Battery according to one of claims 1 to 16, wherein among the multiple battery cells the battery cell arranged at the outermost point along the thickness direction is connected to the first bus component. [18] Battery according to any one of claims 1 to 17, wherein the electrode arrangement comprises two first surfaces and two second surfaces, wherein the two first surfaces are arranged opposite each other along the thickness direction and the two second surfaces are arranged opposite each other along a direction perpendicular to the thickness direction, and the second surface connects the two first surfaces; wherein the area of ​​the first surface is larger than the area of ​​the second surface. [19] Battery according to any one of claims 1 to 18, wherein the expansion pressure of the battery cell in the thickness direction is 1.5 MPa to 2.0 MPa. [20] Battery according to any one of claims 1 to 19, wherein the one-sided coating weight of the negative electrode film layer is 90 mg / 1540.25 mm² 2 up to 170 mg / 1540.25 mm 2 is, optionally 110 mg / 1540.25 mm 2 up to 150 mg / 1540.25 mm 2 . [21] Battery according to any one of claims 1 to 20, wherein the density of the negative electrode film layer at 100% SOC of the battery cell is 1.15 g / cm³ 3 up to 1.36 g / cm³ 3 is, optionally 1.25 g / cm² 3 up to 1.36 g / cm³ 3 . [22] Battery according to any one of claims 1 to 21, wherein the porosity of the negative electrode sheet is 27% to 40%. [23] Battery according to any one of claims 1 to 22, wherein the carbon-based material comprises at least one of artificial graphite and natural graphite. [24] Battery according to any one of claims 1 to 23, wherein the negative electrode active material also comprises a silicon-based material, wherein the mass fraction of the element silicon in the silicon-based material in the negative electrode active material is 0.3% to 10%, optionally 1% to 6%. [25] Battery according to claim 24, wherein the silicon-based material comprises at least one silicon oxide compound and silicon-carbon composite. [26] Battery according to any one of claims 1 to 25, wherein the negative electrode film layer comprises a first negative electrode film layer and a second negative electrode film layer, wherein the second negative electrode film layer is arranged between the first negative electrode film layer and the negative electrode current collector; wherein the negative electrode active material comprises a first negative electrode active material arranged in the first negative electrode film layer and a second negative electrode active material arranged in the second negative electrode film layer, wherein the first negative electrode active material comprises an artificial graphite and the second negative electrode active material comprises one or more of artificial graphite, natural graphite and silicon-based material. [27] Battery according to claim 26, wherein the ratio of the thickness of the first negative electrode film layer to the thickness of the second negative electrode film layer is 3:7 to 7:3, optionally 4:6 to 6:

4. [28] Battery according to claim 26 or 27, wherein the thickness of the first negative electrode film layer is less than or equal to the thickness of the second negative electrode film layer. [29] Battery according to one of claims 26 to 28, wherein the volume-averaged particle size Dv50 of the first negative electrode active material is less than or equal to the volume-averaged particle size Dv50 of the second negative electrode active material. [30] Battery according to any one of claims 26 to 29, wherein the volume-averaged particle size Dv50 of the first negative electrode active material is 7.8 µm to 14.3 µm, optionally 7.8 µm to 11.3 µm; wherein the volume-averaged particle size Dv50 of the second negative electrode active material is 9.5 µm to 18.5 µm, optionally 9.5 µm to 14.6 µm. [31] Battery according to any one of claims 1 to 30, wherein the specific surface area of ​​the negative electrode active material is 0.5 m² 2 / g up to 3 m 2 / g is, optionally 0.6 m 2 / g up to 1.2 m 2 / G. [32] Battery according to any one of claims 1 to 31, wherein the one-sided coating weight of the positive electrode film layer is 200 mg / 1540.25 mm² 2 up to 370 mg / 1540.25 mm 2 is, optionally 240 mg / 1540.25 mm 2 up to 330 mg / 1540.25 mm 2 . [33] Battery according to any one of claims 1 to 32, wherein the density of the positive electrode film layer at 100% SOC of the battery cell is 2.50 g / cm³ 3 up to 2.80 g / cm³ 3 is, optionally 2.55 g / cm² 3 up to 2.70 g / cm³ 3 . [34] Battery according to any one of claims 1 to 33, wherein the porosity of the positive electrode sheet is 25% to 32%. [35] Battery according to any one of claims 1 to 34, wherein the thickness of the positive electrode sheet is 0.13 mm to 0.2 mm. [36] Battery according to any one of claims 1 to 35, wherein the ratio of the thickness of the positive electrode current collector to the thickness of the positive electrode film layer is 0.05 to 0.

3. [37] Battery according to any one of claims 1 to 36, wherein the volume-averaged particle size of the positive electrode active material satisfies the conditions 1 µm ≤ Dv50 ≤ 2 µm and 0.4 µm ≤ Dv10 ≤ 0.7 µm. [38] Battery according to any one of claims 1 to 37, wherein the battery cell comprises an electrolyte solution contained in the housing. [39] Battery according to claim 38, wherein the conductivity of the electrolyte solution at room temperature is 15 mS / cm to 20 mS / cm. [40] Battery according to claim 38 or 39, wherein the electrolyte solution comprises an organic solvent, the organic solvent comprising one or more carbonate solvents and carboxylic acid ester solvents. [41] Battery according to claim 40, wherein the carbonate solvent comprises one or more of ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate and ethyl methyl carbonate. [42] Battery according to claim 40 or 41, wherein the carboxylic acid ester comprises R1-COO-R2, wherein R1 and R2 each independently comprise an alkyl group with 1 to 5 carbon atoms or a halogenated alkyl group with 1 to 5 carbon atoms. [43] Battery according to any one of claims 38 to 42, wherein the electrolyte solution comprises a lithium salt, wherein the lithium salt comprises lithium bis(fluorosulfonyl)imide LiFSI and lithium hexafluorophosphate LiPF6, wherein the molar concentration of the lithium bis(fluorosulfonyl)imide LiFSI is 0.2 mol / L to 0.5 mol / L and the molar concentration of the lithium hexafluorophosphate LiPF6 is 0.5 mol / L to 1.0 mol / L. [44] Battery according to any one of claims 38 to 43, wherein the density ρ of the electrolyte solution at room temperature satisfies the condition 1.05 g / mL ≤ ρ ≤ 1.35 g / mL. [45] Battery according to any one of claims 1 to 44, wherein the dimension of the electrode arrangement along the thickness direction is designated by T, the thickness of the negative single-layer electrode sheet is designated by T1 and the number of layers of the negative electrode sheet stacked in the thickness direction is designated by N; T, T1 and N satisfy the condition 0.3 ≤ (N × T1) / T ≤ 0.

5. [46] Battery according to any one of claims 1 to 45, wherein the charging time of the battery cell from 10% SOC to 80% SOC is 5 minutes to 10.5 minutes. [47] Power-consuming device, characterized by that it comprises a battery according to one of claims 1 to 46 for providing electrical energy.

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