Battery cells, battery packs, energy storage devices and electrical appliances

Abstract

This application discloses a battery cell, a battery device, an energy storage device, and an electrical device. The battery cell includes a casing and at least one electrode assembly. The casing includes a housing with an opening on one side along a first direction and an end cap that closes the opening, forming a receiving cavity between the end cap and the housing. At least one electrode assembly is disposed within the receiving cavity. The electrode assembly includes a positive electrode, a negative electrode, and a spacer sandwiched between the positive and negative electrode. The end of the positive electrode near the end cap extends beyond the spacer, and the portion of the positive electrode near the end cap extending beyond the spacer is bent to the same side to form a positive electrode tab. The end of the negative electrode near the end cap extends beyond the spacer, and the portion of the negative electrode near the end cap extending beyond the spacer is bent to the same side to form a negative electrode tab. The battery cell, battery device, energy storage device, and electrical device provided in this application have high volumetric energy density.

Description

Technical Field

[0001] This application relates to the field of battery technology, and in particular to battery cells, battery devices, energy storage devices, and power consumption devices. Background Technology

[0002] The application of new energy batteries in daily life and industry is becoming increasingly widespread. For example, new energy vehicles equipped with batteries are already widely used, and batteries are also increasingly being applied in energy storage. In new energy vehicles equipped with batteries, the batteries can provide all or part of the power. In the field of energy storage, batteries can be installed in energy storage boxes or directly on the user side.

[0003] With the continuous development of battery technology, the industry is constantly raising the requirements for the volumetric energy density of batteries. Utility Model Content

[0004] To address the aforementioned technical problems, this application provides a battery cell, battery device, energy storage device, and power consumption device with high volumetric energy density.

[0005] This application is achieved through the following technical solution.

[0006] The first aspect of this application provides a battery cell, comprising: a housing, including a housing having an opening on one side along a first direction and an end cap that closes the opening, with a receiving cavity formed between the end cap and the housing; at least one electrode assembly disposed within the receiving cavity, the electrode assembly including a positive electrode, a negative electrode, and a separator sandwiched between the positive electrode and the negative electrode, the end of the positive electrode near the end cap extending beyond the separator, the portion of the positive electrode near the end cap extending beyond the separator bending to the same side to form a positive electrode tab, the end of the negative electrode near the end cap extending beyond the separator, the portion of the negative electrode near the end cap extending beyond the separator bending to the same side to form a negative electrode tab.

[0007] In the technical solution provided in this application, the portion of the positive electrode sheet extending beyond the separator along the first direction near the end cap is bent towards the same side to form a positive electrode tab, and the portion of the negative electrode sheet extending beyond the separator along the first direction near the end cap is bent towards the same side to form a negative electrode tab. This eliminates the need for a folded portion of the tabs, reducing the dimensions of the positive and negative electrode tabs in the first direction, which is beneficial for reducing the size of the battery cell in the first direction, thereby increasing the volumetric energy density. Furthermore, both the positive and negative electrode tabs face the end cap; that is, they extend from the same side, further reducing the space occupied by the electrode assembly in the first direction and further improving the volumetric energy density.

[0008] In some embodiments, the electrode assembly is formed by winding a laminate including a positive electrode, a negative electrode, and an isolator. The portion of the positive electrode near the end cap that extends beyond the isolator includes a plurality of positive conductive portions arranged sequentially at intervals along the winding direction. The plurality of positive conductive portions are bent independently to the same side and stacked to form a positive electrode tab. The portion of the negative electrode near the end cap that extends beyond the isolator includes a plurality of negative conductive portions arranged sequentially at intervals along the winding direction. The plurality of negative conductive portions are bent independently to the same side and stacked to form a negative electrode tab.

[0009] Thus, the electrode assembly has a wound structure. The positive electrode tab is formed by bending and stacking multiple positive conductive parts, which reduces the size of the positive electrode tab in the first direction. The negative electrode tab is formed by bending and stacking multiple negative conductive parts, which reduces the size of the negative electrode tab in the first direction. This reduces the space occupied by the positive and negative electrode tabs in the first direction, thereby increasing the volumetric energy density of the battery cell.

[0010] In some embodiments, the portion of the positive electrode sheet that does not extend beyond the separator along the first direction, the portion of the negative electrode sheet that does not extend beyond the separator along the first direction, and the separator are stacked to form a main body. A protective layer is provided between the end face of the main body facing the end cap and the positive electrode tab and between the main body and the negative electrode tab. The melting point of the protective layer is in the range of 300°C to 500°C.

[0011] By blocking the protective layer between the tabs and the main body, the risk of the separator in the main body being burned by high temperature is reduced when the tabs need to be welded at high temperature. This reduces the probability of short circuit between the positive and negative electrode plates in the electrode assembly and improves the reliability of the battery cell.

[0012] In some embodiments, the material of the protective layer includes an insulating material.

[0013] This design also provides electrical insulation, reducing the likelihood of the positive electrode tab contacting the negative electrode in the main body, and vice versa. This lowers the risk of short circuits in the electrode assembly and further improves the reliability of the battery cell. Furthermore, the protective layer allows the surface of the positive electrode tab facing the main body to be as close as possible to the end face of the main body, and vice versa. This further reduces the space occupied by the electrode assembly in the first direction, thereby increasing the volumetric energy density of the battery cell.

[0014] In some embodiments, the protective layer is adhered to the end face of the body portion facing the end cap.

[0015] The protective layer is attached to the main body by adhesive bonding, which is convenient and helps to improve production efficiency. In addition, the adhesive bonding method can meet the connection strength requirements.

[0016] In some embodiments, the protective layer includes at least one of polyethylene terephthalate adhesive paper, polyimide adhesive paper, polyethylene naphthalate adhesive paper, aramid paper, mica paper, ceramic fiber paper, and polytetrafluoroethylene adhesive paper.

[0017] In some embodiments, the battery cell further includes a positive terminal and a negative terminal respectively disposed on the end cap. The positive terminal is connected to the positive terminal tab through a first adapter piece. The first adapter piece is welded to the positive terminal to form a first solder mark. The first adapter piece is welded to the positive terminal tab to form a second solder mark. There is no overlap between the first solder mark and the second solder mark. The negative terminal is connected to the negative terminal tab through a second adapter piece. The second adapter piece is welded to the negative terminal to form a third solder mark. The second adapter piece is welded to the negative terminal tab to form a fourth solder mark. There is no overlap between the third solder mark and the fourth solder mark.

[0018] The first and second solder marks formed on the first adapter piece have no overlapping portion, allowing the welding of the first adapter piece to the positive electrode tab and the welding of the first adapter piece to the positive electrode post to be performed in stages. This reduces the probability of the two welding processes interfering with each other, lowers the welding difficulty, and improves the welding quality. Similarly, the third and fourth solder marks formed on the second adapter piece have no overlapping portion, allowing the welding of the second adapter piece to the negative electrode tab and the welding of the second adapter piece to the negative electrode post to be performed in stages. This also reduces the probability of the two welding processes interfering with each other, lowers the welding difficulty, and improves the welding quality. In addition, the lower welding difficulty also reduces the probability of burning the insulating component and reduces the risk of short circuits in the electrode assembly.

[0019] In some embodiments, when projected along the first direction, the orthographic projections of the first and second solder marks all fall within the orthographic projection range of the protective layer corresponding to the positive electrode tab, and the orthographic projections of the third and fourth solder marks all fall within the orthographic projection range of the protective layer corresponding to the negative electrode tab.

[0020] This design ensures that during the formation of the first and second solder marks, the protective layer blocks heat transfer from the solder marks, preventing the insulating components from being burned due to the high temperature of the solder marks. Furthermore, during the formation of the third and fourth solder marks, the protective layer also blocks heat transfer from the solder marks, preventing the insulating components from being burned due to the high temperature of the solder marks, thereby reducing the risk of short circuits in the electrode assembly and improving the reliability of the individual battery cells.

[0021] In some embodiments, the battery cell further includes a positive electrode post and a negative electrode post respectively disposed on the end cap. The positive electrode post is directly welded to the positive electrode tab to form a fifth weld mark, and the negative electrode post is directly welded to the negative electrode tab to form a sixth weld mark. When projected along the first direction, the orthogonal projection of the fifth weld mark falls entirely within the orthogonal projection range of the protective layer corresponding to the positive electrode tab, and the orthogonal projection of the sixth weld mark falls entirely within the orthogonal projection range of the protective layer corresponding to the negative electrode tab.

[0022] In this way, the positive electrode post and positive electrode tab are directly welded, and the negative electrode post and negative electrode tab are directly welded, eliminating the need for an adapter plate, further reducing the space occupied by the cavity, and further improving the volumetric energy density. Furthermore, the protective layer can prevent heat transfer from the fifth and sixth solder marks to the main body, making it less likely for the insulating components to be burned due to the high temperature of the solder marks.

[0023] In some embodiments, both the positive electrode tab and the negative electrode tab have a fixing member pressed against the side facing the end cap, and the fixing member is connected to the main body.

[0024] In this way, the fastener can press the positive conductive parts of the positive electrode tab together, reducing the probability of the positive conductive parts opening up, and fixing the position of the positive electrode tab. This is beneficial to improving the welding quality between the positive electrode tab and the positive electrode post or the first adapter piece, and reducing the probability of cold solder joints. Similarly, the fastener can press the negative conductive parts of the negative electrode tab together, reducing the probability of the negative conductive parts opening up, and fixing the position of the negative electrode tab. This is beneficial to improving the welding quality between the negative electrode tab and the negative electrode post or the second adapter piece, and reducing the probability of cold solder joints.

[0025] In some embodiments, the melting point of the fastener is in the range of 300°C to 500°C.

[0026] Because the fastener is close to the electrode tab, welding the electrode tab can easily cause the temperature near the fastener to rise. By making the fastener heat-resistant, the chance of it melting can be reduced, thus maintaining its structure and allowing it to effectively secure the electrode tab, which is beneficial for welding quality. Additionally, the fastener partially obscures the end face of the main body, which also reduces the chance of the insulating components in the main body being burned, lowering the risk of short circuits in the electrode assembly.

[0027] In some embodiments, the material of the fastener includes an insulating material.

[0028] By using insulating materials for the fasteners, the likelihood of short circuits in the electrode assembly due to the fastener design is reduced.

[0029] In some embodiments, the fasteners are bonded to two surfaces of the main body that are opposite each other along a second direction perpendicular to the first direction; the positive electrode tab and the negative electrode tab are respectively bonded to their respective fasteners.

[0030] In this way, the two ends of the fastener are bonded to two opposing surfaces of the main body along the second direction, and the middle part of the fastener is bonded to the positive electrode tab, improving the reliability of the fastener's fixation to the positive electrode tab. Similarly, the two ends of the fastener are bonded to two opposing surfaces of the main body along the second direction, and the middle part of the fastener is bonded to the negative electrode tab, improving the reliability of the fastener's fixation to the negative electrode tab. Furthermore, the bonding method facilitates operation and improves the manufacturing efficiency of the battery cell.

[0031] In some embodiments, the fastener includes at least one of polyethylene terephthalate adhesive paper, polyimide adhesive paper, polyethylene naphthalate adhesive paper, aramid paper, mica paper, ceramic fiber paper, and polytetrafluoroethylene adhesive paper.

[0032] In some embodiments, the portion of the positive electrode sheet that does not extend beyond the separator along the first direction, the portion of the negative electrode sheet that does not extend beyond the separator along the first direction, and the separator are stacked to form a main body. The main body includes a straight portion stacked along the second direction and two corner portions respectively connected to the two ends of the straight portion along a third direction. The first direction, the second direction, and the third direction are mutually perpendicular. The positive electrode tab and the negative electrode tab are spaced apart along the third direction and both extend from the straight portion. Along the second direction, the ratio of the size of the end of the positive electrode tab connected to the main body to the size of the main body is in the range of 1 / 4 to 3 / 4; along the second direction, the ratio of the size of the end of the negative electrode tab connected to the main body to the size of the main body is in the range of 1 / 4 to 3 / 4.

[0033] This configuration ensures an appropriate number of layers in the positive conductive section and a suitable current-carrying area for the positive electrode plate. It satisfies the current-carrying requirements without compromising the dimensional reduction of the positive electrode plate in the first direction or causing material waste due to an excessive number of layers in the positive conductive section. Similarly, it ensures an appropriate number of layers in the negative conductive section and a suitable current-carrying area for the negative electrode tab. This configuration also satisfies the current-carrying requirements without compromising the dimensional reduction of the negative electrode tab in the first direction or causing material waste due to an excessive number of layers in the negative conductive section.

[0034] In some embodiments, the edge of the region of the main body with the positive electrode tab extending along the second direction coincides with a portion of the end face of the main body along the second direction, and the positive electrode tab is bent toward the opposite edge of the end face; and / or, the edge of the region of the main body with the negative electrode tab extending along the second direction coincides with a portion of the end face of the main body along the second direction, and the negative electrode tab is bent toward the opposite edge of the end face.

[0035] The root of the positive electrode tab is positioned close to one edge of the end face of the main body along the second direction and bends towards the other end. This allows a larger positive electrode tab to be positioned in the space on the side of the main body facing the end cap along the first direction, thus ensuring that the positive electrode tab meets the welding area requirements with the positive electrode post or the first adapter piece. Similarly, the root of the negative electrode tab is positioned close to one edge of the end face of the main body along the second direction and bends towards the other end. This allows a larger negative electrode tab to be positioned in the space on the side of the main body facing the end cap along the first direction, thus ensuring that the negative electrode tab meets the welding area requirements with the negative electrode post or the second adapter piece.

[0036] In some embodiments, in the same electrode assembly, the end of the positive electrode tab connected to the main body and the end of the negative electrode tab connected to the main body are disposed near the same end edge of the main body along the second direction.

[0037] Thus, in the same electrode assembly, the positive and negative electrode tabs are positioned on the same side of the main body end face along the second direction, and their bending directions are consistent. Bending in the same direction reduces the risk of positional displacement of the tabs during welding, minimizing problems such as incomplete welds or breakage caused by tab misalignment. By unifying the bending direction, the design and adjustment steps of the welding fixture are simplified, improving production efficiency. Bending the positive and negative tabs in the same direction reduces the risk of uneven stress on the electrode sheets caused by directional differences, reducing wrinkles or damage to the electrode sheets or separators due to tension differences during winding, and facilitating precise control of the tab center distance, meeting the stringent requirements for tab alignment in the winding process.

[0038] In some embodiments, two electrode assemblies are provided and arranged along a second direction, with the positive electrode tabs of the two electrode assemblies bent towards each other along the second direction, and the negative electrode tabs of the two electrode assemblies bent towards each other along the second direction.

[0039] This arrangement allows the two positive electrode tabs to be close to each other, facilitating connection to the same first adapter piece or the same positive electrode post, and also allows the two negative electrode tabs to be close to each other, facilitating connection to the same second adapter piece or the same negative electrode post. The layout is reasonable and simplifies the process.

[0040] In some embodiments, the positive electrode tabs of the two electrode assemblies are arranged opposite each other in a second direction, and the negative electrode tabs of the two electrode assemblies are arranged opposite each other in a second direction.

[0041] This design simplifies the structure of the first adapter or positive terminal connected to the two positive terminals, thereby simplifying the manufacturing process. Furthermore, it simplifies the structure of the second adapter or negative terminal connected to the two negative terminals, further simplifying the manufacturing process.

[0042] In some embodiments, two opposing positive electrode tabs are connected to the positive electrode post disposed on the end cap via the same first adapter piece; two opposing negative electrode tabs are connected to the negative electrode post disposed on the end cap via the same second adapter piece.

[0043] In this way, the two electrode assemblies are connected in parallel and connected to the pole by the first and second adapter pieces, which reduces the number of parts, saves costs, and reduces the number of processes, thus improving production efficiency.

[0044] In some embodiments, two opposing positive electrode tabs are stacked and welded together; two opposing negative electrode tabs are stacked and welded together.

[0045] In this way, the two opposite positive electrode tabs are welded together, and the two opposite negative electrode tabs are welded together, which improves the reliability of the parallel connection of the two electrode components.

[0046] In some embodiments, there is a gap between two opposing positive electrode tabs; there is a gap between two opposing negative electrode tabs.

[0047] This arrangement, with the two positive electrode tabs spaced apart and the two negative electrode tabs spaced apart, reduces the overlap of current paths between the tabs, lowering the risk of excessively high local current density and thus mitigating polarization. Furthermore, by controlling the tab arrangement, the effective current transmission path is shortened, indirectly reducing the battery's internal resistance.

[0048] In some embodiments, the number of layers of the positive conductive portion is in the range of 10 to 50, and the maximum size of the positive electrode tab along the first direction is in the range of 0.2 mm to 1 mm; and / or, the number of layers of the negative conductive portion is in the range of 10 to 50, and the maximum size of the negative electrode tab along the first direction is in the range of 0.2 mm to 1 mm.

[0049] In this embodiment of the application, by eliminating the converging portion of the positive electrode tab and the negative electrode tab, the size of the positive electrode tab and the negative electrode tab along the first direction can be reduced to 0.2mm to 1mm, thereby reducing the space occupied by the tabs in the first direction and improving the volumetric energy density of the battery cell.

[0050] A second aspect of this application provides a battery device comprising a plurality of battery cells provided in the first aspect.

[0051] Because the battery cells provided in the first aspect have high volumetric energy density, the battery device comprising multiple battery cells provided in the first aspect has high volumetric energy density.

[0052] A third aspect of this application provides an energy storage device, which includes a plurality of battery cells provided in the first aspect of this application or a plurality of battery devices provided in the second aspect of this application, wherein the battery cells or battery devices are used to store or provide electrical energy.

[0053] Since the battery cells provided in the first aspect have high volumetric energy density and the battery devices provided in the second aspect have high volumetric energy density, the energy storage device comprising a plurality of battery cells provided in the first aspect or a plurality of battery devices provided in the second aspect has high volumetric energy density.

[0054] The fourth aspect of this application provides an electrical device that includes a plurality of battery cells provided in the first aspect or a plurality of battery devices provided in the second aspect, wherein the battery cells or battery devices are used to store or provide electrical energy.

[0055] Since the battery cells provided in the first aspect have high volumetric energy density and the battery devices provided in the second aspect have high volumetric energy density, the power-consuming device including multiple battery cells provided in the first aspect or multiple battery devices provided in the second aspect has high volumetric energy density.

[0056] The beneficial effects of the embodiments disclosed herein include: providing a battery cell, battery device, energy storage device, and power consumption device with high volumetric energy density. Attached Figure Description

[0057] Various other advantages and benefits will become apparent to those skilled in the art upon reading the detailed description of the preferred embodiments below. The accompanying drawings are for illustrative purposes only and are not intended to limit the scope of this application. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings:

[0058] Figure 1 This is a schematic diagram of the structure of a vehicle according to one or more embodiments;

[0059] Figure 2 This is an exploded perspective view of a battery device according to one or more embodiments;

[0060] Figure 3 This is an exploded perspective view of a battery cell according to one or more embodiments;

[0061] Figure 4 A cross-sectional view of an electrode assembly according to one or more embodiments, formed by cutting with a plane perpendicular to a first direction;

[0062] Figure 5 A cross-sectional view of an electrode assembly according to one or more embodiments, formed by cutting a plane perpendicular to a third direction at the positive electrode tab;

[0063] Figure 6 A cross-sectional view of an electrode assembly according to one or more embodiments, formed by cutting along a plane perpendicular to a third direction at the negative electrode tab;

[0064] Figure 7 A top view of a battery cell according to one or more embodiments;

[0065] Figure 8 for Figure 7 Sectional view at point AA;

[0066] Figure 9 for Figure 8 An enlarged view of a structure at point B in the middle;

[0067] Figure 10This is a schematic diagram of the internal structure of a battery cell having two electrode assemblies according to one or more embodiments;

[0068] Figure 11 for Figure 8 An enlarged view of another structure at point B;

[0069] Figure 12 A top view of two electrode assemblies according to one or more embodiments;

[0070] Figure 13 A side view of a structure of two electrode assemblies according to one or more embodiments;

[0071] Figure 14 This is a side view of another structure of two electrode assemblies according to one or more embodiments.

[0072] Explanation of reference numerals in the attached figures

[0073] 1000 Vehicle; 100 Battery Unit; 200 Controller; 300 Motor; 10 Housing; 101 First Housing; 102 Second Housing; 20 Battery Cell; 1 Electrode Assembly; 11 Positive Electrode; 111 Positive Conductive Part; 12 Negative Electrode; 121 Negative Conductive Part; 13 Separator; 14 Positive Electrode Tab; 15 Negative Electrode Tab; 16 Main Body; 161 Straight Part; 162 Corner Part; 2 Outer Shell; 21 End Cap; 22 Shell; 3 Protective Layer; 41 Positive Electrode Post; 42 Negative Electrode Post; 421 Groove; 51 First Weld Mark; 52 Second Weld Mark; 53 Third Weld Mark; 54 Fourth Weld Mark; 61 First Adapter Piece; 62 Second Adapter Piece; 7 Fixing Component; 8 Pressure Relief Mechanism. Detailed Implementation

[0074] The embodiments of the technical solution of this application will now be described in detail with reference to the accompanying drawings. These embodiments are only used to more clearly illustrate the technical solution of this application and are therefore merely examples, and should not be used to limit the scope of protection of this application.

[0075] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms “comprising” and “having”, and any variations thereof, in the specification and the foregoing description of the drawings are intended to cover non-exclusive inclusion.

[0076] In the description of the embodiments of this application, technical terms such as "first," "second," and "third" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly defined.

[0077] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0078] In the description of the embodiments in this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects are in an "or" relationship.

[0079] In the description of the embodiments of this application, the technical terms "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "circumferential", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed, operated or used in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of this application.

[0080] In the description of the embodiments of this application, unless otherwise expressly specified and limited, technical terms such as "installation," "connection," "joining," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of this application according to the specific circumstances.

[0081] In the description of the embodiments of this application, unless otherwise expressly specified and limited, the technical term "contact" should be interpreted broadly, and can be direct contact, contact through an intermediate medium layer, contact between two contacting parties with substantially no interaction force, or contact between two contacting parties with interaction force.

[0082] The following is a detailed description of this application.

[0083] Currently, new energy batteries are being used more and more widely in daily life and industry. They are not only used in energy storage systems for hydropower, thermal power, wind power, and solar power plants, but also extensively in electric vehicles such as electric bicycles, electric motorcycles, and electric cars, as well as in aerospace and other fields. With the continuous expansion of the application areas of power batteries, the market demand is also constantly increasing.

[0084] A larger battery capacity stores more electrical energy, enabling devices to operate for longer periods and significantly extending battery life. Furthermore, a larger capacity battery means fewer charging cycles, reducing the inconvenience of frequent charging for users and contributing to longer battery lifespan. Additionally, a larger capacity battery reduces the risk of device interruption due to low power, improving user experience and satisfaction. The volumetric energy density of a battery directly relates to its capacity for a given volume; therefore, improving volumetric energy density is one of the key research topics in the industry.

[0085] The inventors of this application have discovered that currently, most battery cells have tabs that include a folded portion and a bent portion. Both the folded portion and the bent portion occupy a large amount of internal space. In particular, the folded portion is quite tall and occupies a large amount of space in the direction in which the tab extends. The inventors have found that the folding of the tab is a major bottleneck in improving energy density. Therefore, finding a way to eliminate the folding of the tab has become a way to improve energy density.

[0086] The inventors of this application discovered through research that by bending and smoothing the positive conductive parts of each layer that make up the tab, that is, by pressing the current collector protrusions of each layer toward the end face of the electrode assembly, the current collector protrusions are stacked together in the direction of tab extension, eliminating the folded part, thereby reducing the overall height of the tab, which is beneficial to reducing the size of the battery cell in the direction of tab extension, thereby increasing the volumetric energy density.

[0087] Based on this design concept, the inventors of this application have designed a battery cell, which includes a housing and at least one electrode assembly disposed in a receiving cavity of the housing. The housing includes a shell with an opening on one side along a first direction and an end cap that closes the opening, with a receiving cavity formed between the end cap and the shell. At least one electrode assembly is disposed in the receiving cavity. The electrode assembly includes a positive electrode, a negative electrode, and a separator sandwiched between the positive electrode and the negative electrode. The end of the positive electrode that approaches the end cap along the first direction extends beyond the separator. The portion of the positive electrode that approaches the end cap along the first direction and extends beyond the separator is bent to the same side to form a positive electrode tab. The end of the negative electrode that approaches the end cap along the first direction extends beyond the separator. The portion of the negative electrode that approaches the end cap along the first direction and extends beyond the separator is bent to the same side to form a negative electrode tab.

[0088] In this design, the portion of the positive electrode sheet extending beyond the separator along the first direction near the end cap is bent towards the same side to form a positive electrode tab. Similarly, the portion of the negative electrode sheet extending beyond the separator along the first direction near the end cap is bent towards the same side to form a negative electrode tab. This eliminates the need for a folded portion of the tabs, reducing the dimensions of the positive and negative electrode tabs in the first direction. This helps to reduce the size of the battery cell in the first direction, thereby increasing the volumetric energy density. Furthermore, both the positive and negative electrode tabs face the end cap, meaning they extend from the same side, further reducing the space occupied by the electrode assembly in the first direction and further improving the volumetric energy density.

[0089] The battery cells provided in this application embodiment can be used, but are not limited to, in battery devices. A battery device may include one or more battery cell assemblies for providing voltage and capacity. A battery cell assembly may include multiple battery cells, which are connected in series, parallel, or mixed connections via busbars.

[0090] In some embodiments, a battery cell assembly is typically formed by arranging multiple battery cells.

[0091] As an example, a battery cell assembly can be a battery module, which is formed by arranging and fixing multiple battery cells together to form an independent module. As another example, a battery module can be formed by bundling multiple battery cells together with cable ties.

[0092] In some embodiments, the battery device may be a battery pack, which includes a housing and one or more individual battery cells housed within the housing.

[0093] As an example, the battery cell assembly can be a battery module, which can be housed in a housing by fixing the battery module in the housing.

[0094] As an example, battery cell assemblies can also be housed in a housing by directly fixing multiple battery cells to the housing.

[0095] In some embodiments, the housing may be part of the vehicle's chassis structure. For example, a portion of the housing may be at least a part of the vehicle's floor, or a portion of the housing may be at least a part of the vehicle's crossbeams and longitudinal beams.

[0096] In this embodiment of the application, the battery cell can be a secondary battery, which refers to a battery cell that can be recharged to activate the active materials and continue to be used after the battery cell has been discharged.

[0097] The battery cell can be a lithium-ion battery, sodium-ion battery, sodium-lithium-ion battery, lithium metal battery, sodium metal battery, lithium-sulfur battery, magnesium-ion battery, nickel-metal hydride battery, nickel-cadmium battery, lead-acid battery, etc., and the embodiments of this application are not limited to this.

[0098] As an example, the battery cell can be a cylindrical battery, a prismatic battery, a pouch battery, or a battery of other shapes. Prismatic batteries include square-shell batteries, blade-shaped batteries, and multi-prismatic batteries, such as hexagonal prismatic batteries. This application does not have any particular limitations.

[0099] A single battery cell includes an electrode assembly. The electrode assembly includes a positive electrode, a negative electrode, and a separator, with the separator positioned between the negative and positive electrodes. During the charging and discharging process of the battery cell, active ions (such as lithium ions) repeatedly insert and extract between the positive and negative electrodes. The separator, positioned between the positive and negative electrodes, prevents short circuits while allowing active ions to pass through.

[0100] In some embodiments, the positive electrode can be a positive electrode sheet, which may include a positive current collector and a layer of positive active material disposed on at least one surface of the positive current collector.

[0101] As an example, the positive current collector has two surfaces opposite each other in its own thickness direction, and the positive active material layer is disposed on either or both of the two opposite surfaces of the positive current collector.

[0102] As an example, the positive current collector can be a metal foil, a conductive polymer material, a carbon material, or a composite current collector. For example, as a metal foil, pure metals, alloys, or surface-treated metals can be used, including but not limited to stainless steel, copper, aluminum, nickel, titanium, or silver. The composite current collector may include a polymer material base layer and a metal layer. The composite current collector can be formed by forming a metal material (aluminum, aluminum alloys, nickel, nickel alloys, titanium, titanium alloys, silver, and silver alloys, etc.) on a polymer material substrate (such as a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0103] As an example, the positive electrode active material layer may include at least one of the following materials: lithium phosphate, lithium transition metal oxide, and their respective modified compounds. However, this application is not limited to these materials, and other conventional materials that can be used as positive electrode active material layers in batteries may also be used. These positive electrode active material layers may be used alone or in combination of two or more. Examples of lithium phosphate include, but are not limited to, at least one of lithium iron phosphate (such as LiFePO4 (also referred to as LFP)), lithium iron phosphate and carbon composites, lithium manganese phosphate (such as LiMnPO4), lithium manganese phosphate and carbon composites, lithium manganese iron phosphate, and lithium manganese iron phosphate and carbon composites. Examples of lithium transition metal oxides may include, but are not limited to, lithium cobalt oxides (such as LiCoO2), lithium nickel oxides (such as LiNiO2), lithium manganese oxides (such as LiMnO2, LiMn2O4), lithium nickel cobalt oxides, lithium manganese cobalt oxides, lithium nickel manganese oxides, lithium nickel cobalt manganese oxides (such as LiNi1 / 3Co1 / 3Mn1 / 3O2 (also abbreviated as NCM333), LiNi0.5Co0.2Mn0.3O2 (also abbreviated as NCM523), LiNi0.5Co The following are included: 0.25Mn0.25O2 (also known as NCM211), LiNi0.6Co0.2Mn0.2O2 (also known as NCM622), LiNi0.8Co0.1Mn0.1O2 (also known as NCM811), lithium nickel cobalt aluminum oxides (such as LiNi0.8Co0.15Al0.05O2), and their modified compounds. Modified compounds refer to substances obtained by doping or coating, etc., based on the above-mentioned materials.

[0104] In some embodiments, the negative electrode can be a negative electrode sheet, and the negative electrode sheet can include a negative current collector.

[0105] As an example, the negative electrode current collector can be a metal foil, a conductive polymer material, a carbon material, or a composite current collector. For example, as a metal foil, pure metals, alloys, or surface-treated metals can be used, including but not limited to stainless steel, copper, aluminum, nickel, titanium, or silver. The composite current collector may include a polymer material substrate and a metal layer. The composite current collector can be formed by forming a metal material (copper, copper alloys, nickel, nickel alloys, titanium, titanium alloys, silver, and silver alloys, etc.) on a polymer material substrate (such as a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0106] As an example, the negative electrode sheet may include a negative current collector and a layer of negative active material disposed on at least one surface of the negative current collector.

[0107] As an example, the negative electrode current collector has two surfaces opposite each other in its own thickness direction, and the negative electrode active material layer is disposed on either or both of the two opposite surfaces of the negative electrode current collector.

[0108] As an example, the negative electrode active material layer may employ a type of negative electrode active material layer known in the art for use in battery cells. As an example, the negative electrode active material layer may include at least one of the following materials: artificial graphite, natural graphite, soft carbon, hard carbon, silicon-based materials, tin-based materials, and lithium titanate, etc. Silicon-based materials may be selected from at least one of elemental silicon, silicon oxide compounds, silicon-carbon composites, silicon-nitrogen composites, and silicon alloys. Tin-based materials may be selected from at least one of elemental tin, tin oxide compounds, and tin alloys. However, this application is not limited to these materials, and other conventional materials that can be used as negative electrode active material layers in battery cells may also be used. These negative electrode active material layers may be used alone or in combination of two or more.

[0109] In some embodiments, the positive current collector can be made of aluminum, and the negative current collector can be made of copper.

[0110] In some embodiments, the electrode assembly further includes an isolator disposed between the positive and negative electrodes.

[0111] In some embodiments, the separator is a separator membrane. This application does not impose any particular limitation on the type of separator membrane; any known porous separator membrane with good chemical and mechanical stability can be selected.

[0112] As an example, the main material of the separator can be selected from at least one of glass fiber, non-woven fabric, polyethylene, polypropylene, polyvinylidene fluoride, and ceramic. The separator can be a single-layer film or a multi-layer composite film, without particular limitation. When the separator is a multi-layer composite film, the materials of each layer can be the same or different, without particular limitation. The separator can be a single component located between the positive and negative electrodes, or it can be attached to the surfaces of the positive and negative electrodes. An inorganic particle coating, an organic particle coating, or an organic / inorganic composite coating can also be applied to the surface of the separator.

[0113] In some embodiments, the separator is a solid electrolyte. The solid electrolyte is disposed between the positive and negative electrodes, serving both to transport ions and to isolate the positive and negative electrodes.

[0114] The electrode assembly can be a wound structure, a stacked structure, or a hybrid structure of wound and stacked.

[0115] In some embodiments, the electrode assembly is a wound structure. The positive electrode and the negative electrode are wound into a wound structure.

[0116] In some implementations, the electrode assembly is a stacked structure.

[0117] As an example, multiple positive and negative electrode plates can be set, and multiple positive and multiple negative electrode plates can be stacked alternately.

[0118] As an example, multiple positive electrode sheets can be set, and negative electrode sheets are folded to form multiple stacked folded segments, with a positive electrode sheet sandwiched between adjacent folded segments.

[0119] As an example, both the positive and negative electrode sheets are folded to form multiple stacked folded segments.

[0120] As an example, multiple separators can be provided, each positioned between any adjacent positive or negative electrode plates.

[0121] As an example, the separator can be continuously arranged between any adjacent positive or negative electrode plates by folding or rolling.

[0122] In some embodiments, the electrode assembly can be cylindrical, flat, or polygonal, etc.

[0123] In some embodiments, the electrode assembly is provided with tabs that allow current to be drawn from the electrode assembly. The tabs include a positive tab and a negative tab.

[0124] The technical solutions described in the embodiments of this application are applicable to various electrical devices that use battery cells or battery devices, such as mobile phones, portable devices, laptops, electric vehicles, electric toys, power tools, vehicles, ships and spacecraft, etc. For example, spacecraft include airplanes, rockets, space shuttles and spacecraft.

[0125] The technical solutions described in the embodiments of this application are applicable to various energy storage devices that use battery cells or battery devices, such as energy storage containers or energy storage cabinets.

[0126] In the following embodiments, for ease of explanation, a vehicle 1000 is used as an example of an electrical device according to an embodiment of this application. The description is as follows with reference to the accompanying drawings.

[0127] Figure 1 This is a structural schematic diagram of a vehicle 1000 according to one or more embodiments.

[0128] Vehicle 1000 can be a gasoline-powered vehicle, a natural gas-powered vehicle, or a new energy vehicle. New energy vehicles can be pure electric vehicles, hybrid electric vehicles, or range-extended vehicles, etc. For example... Figure 1 As shown, a battery device 100 is installed inside the vehicle 1000. The battery device 100 can be located at the bottom, front, or rear of the vehicle 1000. The battery device 100 can be used to power the vehicle 1000; for example, the battery device 100 can serve as the operating power source for the vehicle 1000. The vehicle 1000 may also include a controller 200 and a motor 300. The controller 200 is used to control the battery device 100 to supply power to the motor 300, for example, to meet the power needs of the vehicle 1000 during starting, navigation, and driving.

[0129] In some embodiments of this application, the battery device 100 can not only serve as the operating power source for the vehicle 1000, but also as the driving power source for the vehicle 1000, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1000.

[0130] Figure 2 This is an exploded perspective view of a battery device 100 according to one or more embodiments.

[0131] like Figure 2 As shown, the battery device 100 includes a housing 10 and at least one battery cell 20. The housing 10 has a receiving space, in which at least one battery cell 20 is received.

[0132] In some embodiments of this application, the housing 10 may include a first housing 101 and a second housing 102. The first housing 101 and the second housing 102 are fastened together, forming an accommodating space inside the housing 10 to accommodate the battery cell 20. This accommodating space may be sealed or unsealed.

[0133] The second box 102 can be a hollow structure with one end open, and the first box 101 can be a plate-like structure. The first box 101 covers the open side of the second box 102 so that the first box 101 and the second box 102 together define the accommodating space. Alternatively, the first box 101 and the second box 102 can both be hollow structures with one side open, and the open side of the first box 101 covers the open side of the second box 102. Of course, the box 10 formed by the first box 101 and the second box 102 can be of various shapes, such as a cylinder, a cuboid, etc.

[0134] In the battery device 100, there can be multiple battery cells 20, which can be connected in series, parallel, or in a mixed manner. A mixed connection means that multiple battery cells 20 are connected in both series and parallel configurations. Multiple battery cells 20 can be directly connected in series, parallel, or in a mixed manner, and then the entire assembly of the multiple battery cells 20 is placed in the receiving space formed by the second housing 102 and the first housing 101. Alternatively, the battery device 100 can also consist of multiple battery cells 20 first connected in series, parallel, or in a mixed manner to form battery modules 30, and then these battery modules are connected in series, parallel, or in a mixed manner to form a whole, which is then housed in the receiving space formed by the second housing 102 and the first housing 101. The battery device 100 may also include other structures; for example, it may include a busbar component for electrical connection between the multiple battery cells 20.

[0135] Below, refer to Figures 3 to 14 Some embodiments of this application will be described in detail.

[0136] Figure 3 This is an exploded perspective view of a battery cell according to one or more embodiments; Figure 4 A cross-sectional view of an electrode assembly according to one or more embodiments, formed by cutting with a plane perpendicular to a first direction; Figure 5 A cross-sectional view of an electrode assembly according to one or more embodiments, formed by cutting a plane perpendicular to a third direction at the positive electrode tab; Figure 6 A cross-sectional view of an electrode assembly according to one or more embodiments, formed by cutting along a plane perpendicular to a third direction at the negative electrode tab; Figure 7 A top view of a battery cell according to one or more embodiments; Figure 8 for Figure 7 Sectional view at point AA; Figure 9 for Figure 8 An enlarged view of a structure at point B in the middle; Figure 10 This is a schematic diagram of the internal structure of a battery cell having two electrode assemblies according to one or more embodiments; Figure 11 for Figure 8 An enlarged view of another structure at point B; Figure 12 A top view of two electrode assemblies according to one or more embodiments; Figure 13 A side view of a structure of two electrode assemblies according to one or more embodiments; Figure 14 This is a side view of another structure of two electrode assemblies according to one or more embodiments.

[0137] In some embodiments of this application, for ease of explanation, a first direction, a second direction, and a third direction are defined, and the first direction, the second direction, and the third direction are directions perpendicular to each other. For ease of explanation, as shown below... Figures 3 to 14 As shown by the arrows in the diagram, the direction of arrow X is the first direction, the direction of arrow Y is the second direction, and the direction of arrow Z is the third direction.

[0138] The first aspect of this application provides a battery cell 20, such as Figures 3 to 6 As shown, the battery cell 20 includes a housing 2 and at least one electrode assembly 1 disposed in the receiving cavity of the housing 2. The housing 2 includes a shell 22 with an opening on one side along the first direction X and an end cap 21 that closes the opening. The receiving cavity is formed between the end cap 21 and the shell 22. At least one electrode assembly 1 is disposed in the receiving cavity. The electrode assembly 1 includes a positive electrode 11, a negative electrode 12 and a separator 13 sandwiched between the positive electrode 11 and the negative electrode 12. The end of the positive electrode 11 that is close to the end cap 21 along the first direction X extends beyond the separator 13. The portion of the positive electrode 11 that is close to the end cap 21 along the first direction X and extends beyond the separator 13 is bent to the same side to form a positive electrode tab 14. The end of the negative electrode 12 that is close to the end cap 21 along the first direction X extends beyond the separator 13. The portion of the negative electrode 12 that is close to the end cap 21 along the first direction X and extends beyond the separator 13 is bent to the same side to form a negative electrode tab 15.

[0139] The outer casing 2 can be made of steel, aluminum, plastic (such as polypropylene), composite metal (such as copper-aluminum composite), or aluminum-plastic film. In some embodiments, the outer casing 2 can be a sealed structure or a non-sealed structure. As an example, when the outer casing 2 is a non-sealed structure, it serves to protect the electrode assembly 1, and a sealing bag is also included between the outer casing 2 and the electrode assembly 1. The sealing bag is used to encapsulate the electrode assembly 1 and the electrolyte. Specifically, the sealing bag can be a bag-shaped insulating component or an aluminum-plastic film. When the outer casing 2 is a sealed structure, it is used to encapsulate the electrode assembly 1 and electrolyte components. Exemplarily, the outer casing 2 can be cylindrical or prismatic. Prismatic shapes include square shells, blade shapes, and polygonal prisms, such as hexagonal prisms, etc., and this application does not have any particular limitations.

[0140] End cap 21 refers to a component that covers the opening of housing 22 to isolate the internal environment of battery cell 20 from the external environment. The shape of end cap 21 can be adapted to the shape of housing 22 to fit it. Optionally, end cap 21 can be made of a material with certain hardness and strength, so that end cap 21 is not easily deformed under pressure or impact, allowing battery cell 20 to have higher structural strength and improved safety performance. End cap 21 can also be provided with a pressure relief mechanism 8 for releasing internal pressure when the internal pressure or temperature of battery cell 20 reaches a threshold. Pressure relief mechanism 8 can be, but is not limited to, an explosion-proof valve. The material of end cap 21 can also be various, such as copper, iron, aluminum, aluminum alloy, steel, titanium alloy, and copper alloy, etc., and this application embodiment does not impose special limitations on this. In some embodiments of this application, an insulating structure can also be provided on the inner side of end cap 21. The insulating structure can be used to isolate the electrical connection components inside housing 22 from end cap 21 to reduce the risk of short circuit. For example, the insulating structure can be made of plastic, rubber, etc.

[0141] The housing 22 is a component used to cooperate with the end cap 21 to form the internal environment of the battery cell 20. This internal environment can accommodate the electrode assembly 1, electrolyte, and other components. The housing 22 and the end cap 21 are independent components. An opening is provided on the housing 22, and the end cap 21 closes the opening to form the internal environment of the battery cell 20. The housing 22 can be of various shapes and sizes, such as cuboid, cylindrical, or hexagonal prism. Specifically, the shape of the housing 22 can be determined according to the specific shape and size of the electrode assembly 1. The housing 22 can be made of various materials, such as copper, iron, aluminum, aluminum alloy, plastic, steel, titanium alloy, and copper alloy, etc. This application embodiment does not impose any special limitations on these materials.

[0142] Electrode assembly 1 is the component in the battery cell 20 where the electrochemical reaction occurs. The casing 2 may contain one or more electrode assemblies 1. Electrode assembly 1 includes a positive electrode 11, a negative electrode 12, and a separator 13, with the separator 13 disposed between the negative electrode 12 and the positive electrode 11. During the charging and discharging process of the battery cell 20, active ions (e.g., lithium ions) repeatedly insert and extract between the positive electrode 11 and the negative electrode 12. The separator 13, disposed between the positive and negative electrode 11, prevents short circuits between the positive and negative electrodes while allowing active ions to pass through. The positive electrode 11 includes a positive current collector and a layer of positive active material disposed on at least one surface of the positive current collector. A positive electrode active material layer is coated on the surface of the positive electrode current collector; the positive electrode current collector includes a positive electrode current collector portion and a positive electrode protrusion portion protruding from the positive electrode current collector portion. The positive electrode current collector portion is coated with a positive electrode active material layer, and at least a portion of the positive electrode protrusion portion is not coated with a positive electrode active material layer. At least a portion of the positive electrode protrusion portion is the portion of the positive electrode sheet 11 extending beyond the separator 13 at one end of the end cap 21 along the first direction X. This portion is bent to the same side to form a positive electrode tab 14. The negative electrode 12 includes a negative current collector and a negative active material layer disposed on at least one surface of the negative current collector. The negative active material layer is coated on the surface of the negative current collector. The negative current collector includes a negative current collector portion and a negative current convex portion protruding from the negative current collector portion. The negative current collector portion is coated with the negative active material layer. At least a portion of the negative current convex portion is not coated with the negative active material layer. At least a portion of the negative current convex portion is the portion of the positive electrode 11 that extends beyond the separator 13 at one end of the end cap 21 along the first direction X. This portion is bent to the same side to form a negative electrode tab 15. The positive current collector portion, the portion of the positive current convex portion that does not extend beyond the separator 13, the negative current collector portion, the portion of the negative current convex portion that does not extend beyond the separator 13, and the separator 13 are stacked to form the main body portion 16 of the electrode assembly 1.

[0143] Understandably, since the positive electrode 11 has a sheet-like structure, the portion of the positive electrode 11 extending beyond the separator 13 is also a sheet-like structure. When bent, this portion can be bent to the same vertical side as its shape before bending. Similarly, since the negative electrode 12 has a sheet-like structure, the portion of the negative electrode 12 extending beyond the separator 13 is also a sheet-like structure. When bent, this portion can be bent to the same vertical side as its shape before bending.

[0144] It is understandable that electrode assembly 1 can be a stacked structure or a hybrid structure of winding and stacking.

[0145] For example, electrode assembly 1 is a wound structure. A positive electrode 11 and a negative electrode 12 are wound into a wound structure, with a spacer 13 sandwiched between the positive electrode 11 and the negative electrode 12. The positive electrode 11 includes a plurality of positive electrode protrusions spaced apart sequentially along the winding direction C. The portion of each positive electrode protrusion extending beyond the spacer is independently bent to the same side and stacked to form a positive electrode tab 14. The negative electrode 12 includes a plurality of negative electrode protrusions spaced apart sequentially along the winding direction C. The portion of each negative electrode protrusion extending beyond the spacer 13 is independently bent to the same side and stacked to form a negative electrode tab 15.

[0146] For example, the electrode assembly 1 has a stacked structure. Multiple positive electrode plates 11 and multiple negative electrode plates 12 can be provided, with the multiple positive electrode plates 11 and multiple negative electrode plates 12 stacked alternately. A spacer 13 is sandwiched between adjacent positive electrode plates 11 and negative electrode plates 12. The positive electrode protrusions of the multiple positive electrode plates 11 that extend beyond the spacer 13 are independently bent to the same side and stacked to form a positive electrode tab 14. The negative electrode protrusions of the multiple negative electrode plates 12 that extend beyond the spacer 13 are independently bent to the same side and stacked to form a negative electrode tab 15.

[0147] It should be noted that the bending angle of the portion of the positive electrode 11 extending beyond the separator 13 at the end of the end cap 21 along the first direction X can be any angle not greater than 90° and as close to 90° as possible. This bending angle refers to the angle turned from the direction pointing from the first direction X toward the end cap 21 toward the position after bending. In this way, the portion of the positive electrode 11 extending beyond the separator 13 is as flat as possible on the end face of the main body 16, thereby making the size of the formed positive electrode tab 14 smaller in the first direction X, thereby reducing the space occupied in the first direction X.

[0148] In the embodiments of this application, the portion of the positive electrode 11 extending beyond the separator 13 at one end near the end cap 21 along the first direction X is bent toward the same side to form a positive electrode tab 14, and the portion of the negative electrode 12 extending beyond the separator 13 at one end near the end cap 21 along the first direction X is bent toward the same side to form a negative electrode tab 15. This eliminates the need for a folded portion of the tabs, reducing the dimensions of the positive electrode tab 14 and the negative electrode tab 15 in the first direction X, which helps to reduce the size of the battery cell 20 in the first direction X, thereby increasing the volumetric energy density. Furthermore, both the positive electrode tab 14 and the negative electrode tab 15 face the end cap 21, meaning they extend from the same side, further reducing the space occupied by the electrode assembly 1 in the first direction X and further increasing the volumetric energy density.

[0149] In the embodiments of this application, "multiple" means two or more.

[0150] In some embodiments of this application, such as Figures 3 to 6As shown, the electrode assembly 1 is formed by winding a laminate including a positive electrode 11, a negative electrode 12 and an insulating member 13. The portion of the positive electrode 11 extending beyond the insulating member 13 at one end near the end cap 21 along the first direction X includes a plurality of positive conductive portions 111 arranged sequentially at intervals along the winding direction C. The plurality of positive conductive portions 111 are bent independently to the same side and stacked to form a positive electrode tab 14. The portion of the negative electrode 12 extending beyond the insulating member 13 at one end near the end cap 21 along the first direction X includes a plurality of negative conductive portions 121 arranged sequentially at intervals along the winding direction C. The plurality of negative conductive portions 121 are bent independently to the same side and stacked to form a negative electrode tab 15.

[0151] It is understood that the positive conductive portion 111 refers to the portion of the positive electrode protrusion that extends beyond the insulating member 13, therefore, the positive conductive portion 111 is included in the positive electrode protrusion of the positive electrode plate 11. The negative conductive portion 121 refers to the portion of the negative electrode protrusion that extends beyond the insulating member 13, therefore, the negative conductive portion 121 is included in the negative electrode protrusion of the negative electrode plate 12.

[0152] It is understood that bending multiple positive conductive portions 111 to the same side means that the multiple positive conductive portions 111 bend in the same straight line direction, and after bending, at least a portion of each positive conductive portion 111 is stacked in the first direction X. For example, the stacked portions of the multiple positive conductive portions 111 in the first direction X can be connected as a single unit by welding. Similarly, bending multiple negative conductive portions 121 to the same side means that the multiple negative conductive portions 121 bend in the same straight line direction, and after bending, at least a portion of each negative conductive portion 121 is stacked in the first direction X. For example, the stacked portions of the multiple negative conductive portions 121 in the first direction X can be connected as a single unit by welding.

[0153] Thus, the electrode assembly 1 has a wound structure. The positive electrode tab 14 is formed by bending and stacking multiple positive conductive parts 111, which reduces the size of the positive electrode tab 14 in the first direction X. The negative electrode tab 15 is formed by bending and stacking multiple negative conductive parts 121, which reduces the size of the negative electrode tab 15 in the first direction X. This reduces the space occupied by the positive electrode tab 14 and the negative electrode tab 15 in the first direction X, thereby increasing the volumetric energy density of the battery cell 20.

[0154] In some embodiments of this application, such as Figure 5 and Figure 6 As shown, the portion of the positive electrode 11 that does not extend beyond the separator 13 along the first direction X, the portion of the negative electrode 12 that does not extend beyond the separator 13 along the first direction X, and the separator 13 are stacked to form a main body 16. A protective layer 3 is provided between the end face of the main body 16 facing the end cap 21 and the positive electrode tab 14 and the negative electrode tab 15. The melting point of the protective layer 3 is in the range of 300℃ to 500℃.

[0155] For example, the melting point of the protective layer 3 can be, but is not limited to, 300℃, 310℃, 320℃, 330℃, 340℃, 350℃, 360℃, 370℃, 380℃, 390℃, 400℃, 410℃, 420℃, 430℃, 440℃, 450℃, 460℃, 470℃, 480℃, 490℃, and 500℃.

[0156] by Figure 5 The directions shown are used as an example for explanation. Figure 5 The dashed line represents the plane where the edge of the isolator 13 is located near the end cap 21 along the first direction X. The portion of the electrode assembly 1 below the dashed line is the main body 16. The portion of the positive electrode 11 above the dashed line forms the positive electrode tab 14. Figure 6 The portion of the negative electrode plate 12 located above the dotted line forms the negative electrode tab 15.

[0157] For example, the protective layer 3 is bonded to the end face of the main body 16 facing the end cap 21.

[0158] For example, the protective layer 3 is bonded to the surface of the positive electrode tab 14 facing the main body portion 16, and the protective layer 3 is bonded to the surface of the negative electrode tab 15 facing the main body portion 16.

[0159] By blocking the protective layer 3 between the tabs (including the positive tab 14 and the negative tab 15) in the main body 16, the risk of the separator 13 in the main body 16 being burned by high temperature is reduced when the tabs need to be welded at high temperature. This reduces the probability of short circuit between the positive electrode 11 and the negative electrode in the electrode assembly 1 and improves the reliability of the battery cell 20.

[0160] In some embodiments of this application, such as Figure 5 and Figure 6 As shown, the material of protective layer 3 includes insulating material.

[0161] Thus, the protective layer 3 also provides electrical insulation, reducing the probability of the positive electrode tab 14 contacting the negative electrode plate 12 in the main body 16, and reducing the probability of the negative electrode tab 15 contacting the positive electrode plate 11 in the main body 16. This reduces the risk of short circuits in the electrode assembly 1 and further improves the reliability of the battery cell 20. Furthermore, due to the protective layer 3, the surface of the positive electrode tab 14 facing the main body 16 can be brought as close as possible to the end face of the main body 16, and the surface of the negative electrode tab 15 facing the main body 16 can be brought as close as possible to the end face of the main body 16. This further reduces the space occupied by the electrode assembly 1 in the first direction X and further increases the volumetric energy density of the battery cell 20.

[0162] In some embodiments of this application, such as Figure 5 and Figure 6 As shown, the protective layer 3 is bonded to the end face of the main body 16 facing the end cap 21.

[0163] The protective layer 3 is attached to the main body 16 by adhesive bonding, which is convenient and helps to improve production efficiency. In addition, the adhesive bonding method can meet the connection strength requirements.

[0164] In some embodiments of this application, such as Figure 5 and Figure 6 As shown, the protective layer 3 includes at least one of polyethylene terephthalate adhesive paper, polyimide adhesive paper, polyethylene naphthalate adhesive paper, aramid paper, mica paper, ceramic fiber paper, and polytetrafluoroethylene adhesive paper.

[0165] In some embodiments of this application, such as Figures 7 to 10 As shown, the battery cell 20 also includes a positive terminal 41 and a negative terminal 42 respectively disposed on the end cover 21. The positive terminal 41 is connected to the positive electrode tab 14 through a first adapter piece 61. The first adapter piece 61 and the positive terminal 41 are welded together to form a first solder mark 51. The first adapter piece 61 and the positive electrode tab 14 are welded together to form a second solder mark 52. There is no overlap between the first solder mark 51 and the second solder mark 52. The negative terminal 42 is connected to the negative electrode tab 15 through the second adapter piece 62. The second adapter piece 62 and the negative terminal 42 are welded together to form a third solder mark 53. The second adapter piece 62 and the negative electrode tab 15 are welded together to form a fourth solder mark 54. There is no overlap between the third solder mark 53 and the fourth solder mark 54.

[0166] It is understandable that, such as Figure 9 As shown in the figure, the dashed line indicates the boundary between the negative electrode tab 15 and the main body 16.

[0167] The first solder mark 51 and the second solder mark 52 formed on the first adapter piece 61 have no overlapping portion, which allows the welding of the first adapter piece 61 to the positive electrode tab 14 and the welding of the first adapter piece 61 to the positive electrode post 41 to be performed in stages, reducing the probability of mutual interference between the two welding operations, reducing the welding difficulty, and improving the welding quality. Similarly, the third solder mark 53 and the fourth solder mark 54 formed on the second adapter piece 62 have no overlapping portion, which allows the welding of the second adapter piece 62 to the negative electrode tab 15 and the welding of the second adapter piece 62 to the negative electrode post 42 to be performed in stages, reducing the probability of mutual interference between the two welding operations, reducing the welding difficulty, and improving the welding quality. In addition, the lower welding difficulty also reduces the probability of burning the insulating component 13 and reduces the risk of short circuit in the electrode assembly 1.

[0168] In some embodiments of this application, such as Figures 7 to 10As shown, when projected along the first direction X, the orthographic projections of the first solder mark 51 and the second solder mark 52 all fall within the orthographic projection range of the protective layer 3 corresponding to the positive electrode tab 14, and the orthographic projections of the third solder mark 53 and the fourth solder mark 54 all fall within the orthographic projection range of the protective layer 3 corresponding to the negative electrode tab 15.

[0169] Projecting along the first direction X, the orthographic projections of the first solder mark 51 and the second solder mark 52 all fall within the orthographic projection range of the protective layer 3 corresponding to the positive electrode tab 14. This ensures that during the welding process of forming the first solder mark 51 and the second solder mark 52, the protective layer 3 blocks the heat transfer of the solder mark, preventing the insulating component 13 from being burned due to the high temperature of the solder mark. Projecting along the first direction X, the orthographic projections of the third solder mark 53 and the fourth solder mark 54 all fall within the orthographic projection range of the protective layer 3 corresponding to the negative electrode tab 15. This ensures that during the welding process of forming the third solder mark 53 and the fourth solder mark 54, the protective layer 3 blocks the heat transfer of the solder mark, preventing the insulating component 13 from being burned due to the high temperature of the solder mark, thereby reducing the risk of short circuit in the electrode assembly 1 and improving the reliability of the battery cell 20.

[0170] In some embodiments of this application, such as Figure 7 and Figure 11 As shown, the battery cell 20 also includes a positive electrode post 41 and a negative electrode post 42 respectively disposed on the end cover 21. The positive electrode post 41 is directly welded to the positive electrode tab 14 to form a fifth weld mark (not shown in the figure), and the negative electrode post 42 is directly welded to the negative electrode tab 15 to form a sixth weld mark (not shown in the figure). Projected along the first direction X, the orthographic projection of the fifth weld mark falls entirely within the orthographic projection range of the protective layer 3 corresponding to the positive electrode tab 14, and the orthographic projection of the sixth weld mark falls entirely within the orthographic projection range of the protective layer 3 corresponding to the negative electrode tab 15.

[0171] It is understandable that, such as Figure 11 As shown in the figure, the dashed line indicates the boundary between the negative electrode tab 15 and the main body 16.

[0172] In this way, the positive electrode post 41 and the positive electrode tab 14 are directly welded, and the negative electrode post 42 and the negative electrode tab 15 are directly welded, eliminating the need for an adapter piece, further reducing the space occupied by the cavity, and further improving the volumetric energy density. In addition, the protective layer 3 can block the heat transfer from the fifth and sixth solder marks to the main body 16, making it less likely for the insulating component 13 to be burned due to the high temperature of the solder marks.

[0173] In some embodiments of this application, such as Figure 10 As shown, both the positive electrode tab 14 and the negative electrode tab 15 have a fixing member 7 pressed against the side facing the end cover 21, and the fixing member 7 is connected to the main body 16.

[0174] It is understandable that the positive electrode tab 14 is pressed against the side of each layer of positive electrode conductive part 111 facing the end cover 21 by the fixing member 7, and the negative electrode tab 15 is pressed against the side of each layer of negative electrode conductive part 121 facing the end cover 21 by the fixing member 7.

[0175] Thus, the fixing member 7 can press the positive conductive parts 111 of the positive electrode tab 14 together, reducing the probability of the positive conductive parts 111 opening, fixing the position of the positive electrode tab 14, which is beneficial to improving the welding quality between the positive electrode tab 14 and the positive electrode post 41 or the first adapter piece 61, and reducing the probability of cold solder joints. The fixing member 7 can also press the negative conductive parts 121 of the negative electrode tab 15 together, reducing the probability of the negative conductive parts 121 opening, fixing the position of the negative electrode tab 15, which is beneficial to improving the welding quality between the negative electrode tab 15 and the negative electrode post 42 or the second adapter piece 62, and reducing the probability of cold solder joints.

[0176] In some embodiments of this application, such as Figure 10 As shown, the melting point of fastener 7 is in the range of 300℃~500℃.

[0177] For example, the melting point of the fastener 7 can be, but is not limited to, 300°C, 310°C, 320°C, 330°C, 340°C, 350°C, 360°C, 370°C, 380°C, 390°C, 400°C, 410°C, 420°C, 430°C, 440°C, 450°C, 460°C, 470°C, 480°C, 490°C, and 500°C.

[0178] Since the fixing member 7 is close to the electrode tab, the temperature near the fixing member 7 is prone to rise during electrode tab welding. By making the fixing member 7 heat-resistant, the probability of the fixing member 7 melting can be reduced, thereby maintaining the structure of the fixing member 7 and enabling it to effectively fix the electrode tab, which is beneficial to the welding quality. In addition, the fixing member 7 will cover part of the end face of the main body 16, which can also reduce the probability of the isolator 13 of the main body 16 being burned and reduce the risk of short circuit of the electrode assembly 1.

[0179] In some embodiments of this application, such as Figure 10 As shown, the material of the fastener 7 includes insulating material.

[0180] For example, the fastener 7 includes at least one of polyethylene terephthalate adhesive paper, polyimide adhesive paper, polyethylene naphthalate adhesive paper, aramid paper, mica paper, ceramic fiber paper, and polytetrafluoroethylene adhesive paper.

[0181] By using insulating material for the fastener 7, the probability of short circuit in the electrode assembly 1 due to the fastener 7 is reduced.

[0182] In some embodiments of this application, such as Figure 10 As shown, the fastener 7 is bonded to two surfaces of the main body 16 opposite to each other along the second direction Y, which is perpendicular to the first direction X; the positive electrode tab 14 and the negative electrode tab 15 are respectively bonded to their respective fasteners 7.

[0183] Thus, the two ends of the fixing member 7 are bonded to two opposing surfaces of the main body 16 along the second direction Y, and the middle part of the fixing member 7 is bonded to the positive electrode tab 14, improving the reliability of the fixing member 7 in fixing the positive electrode tab 14. Furthermore, the two ends of the fixing member 7 are bonded to two opposing surfaces of the main body 16 along the second direction Y, and the middle part of the fixing member 7 is bonded to the negative electrode tab 15, improving the reliability of the fixing member 7 in fixing the negative electrode tab 15. In addition, the bonding method facilitates operation and improves the manufacturing efficiency of the battery cell 20.

[0184] In some embodiments of this application, such as Figure 4 , Figures 12 to 14 As shown, the electrode assembly 1 includes a main body 16 formed by winding a portion of a positive electrode 11, a portion of a negative electrode 12, and a separator 13. The main body 16 includes a straight portion 161 stacked along the second direction Y and two corner portions 162 respectively connected to the two ends of the straight portion 161 along the third direction Z. The first direction X, the second direction Y, and the third direction Z are mutually perpendicular. The positive electrode tab 14 and the negative electrode tab 15 are spaced apart along the third direction Z and both extend from the straight portion 161. Along the second direction Y, the ratio of the size of the end of the positive electrode tab 14 connected to the main body 16 to the size of the main body 16 is in the range of 1 / 4 to 3 / 4. Along the second direction Y, the ratio of the size L1 of the end of the negative electrode tab 15 connected to the main body 16 to the size L2 of the main body 16 is in the range of 1 / 4 to 3 / 4.

[0185] It is understandable that the end where the negative electrode tab 15 connects to the main body 16 is the root of the negative electrode tab 15, and the dimension of the end where the negative electrode tab 15 connects to the main body 16 along the second direction Y is the dimension of the area of ​​the main body 16 extending out of the negative electrode tab 15 along the second direction Y. See Figure 12 The shaded area in the diagram represents the region where the main body 16 extends from the negative electrode tab 15 or the positive electrode tab 14. See also... Figure 13 In the figure, the electrode assembly 1 located on the left side, counting from left to right, the distance between the position where the first negative conductive part 121 extends from the main body 16 and the position where the last negative conductive part 121 extends is the dimension L1. The dimension of the straight part 161 of the main body 16 along the second direction Y is the dimension L2. The structure of the positive electrode tab 14 is similar and will not be described in detail here.

[0186] For example, see Figure 13In the figure, the electrode assembly 1 located on the left, counting from left to right, from the position where the first negative conductive part 121 extends from the main body 16 to the position where the last negative conductive part 121 extends, the size of the negative electrode tab 15 in the first direction X gradually increases. Between the position where the last negative conductive part 121 extends and the right edge of the main body 16, the size of the negative electrode tab 15 in the first direction X remains essentially constant. The structure of the positive electrode tab 14 is similar and will not be described further here. See [link to documentation] Figure 12 In the figure, the shaded area represents the part whose size gradually increases in the first direction X, while the unshaded part of the tab represents the part whose size is basically the same.

[0187] For example, such as Figure 12 As shown, two electrode assemblies 1 are arranged along the second direction Y. The part of the same electrode assembly 1 located between two dashed lines distributed along the third direction Z is the main body 16 of the electrode assembly 1, and the other two semi-circular parts are the two corner parts 162 of the electrode assembly 1.

[0188] For example, along the second direction Y, the ratio of the size of the end of the positive electrode tab 14 connected to the main body 16 to the size of the main body 16 can be, but is not limited to, 1 / 4, 1 / 3, 5 / 12, 1 / 2, 7 / 12, 2 / 3, or 3 / 4.

[0189] For example, along the second direction Y, the ratio of the dimension L1 of the end of the negative electrode tab 15 connected to the main body 16 to the dimension L2 of the main body 16 can be, but is not limited to, 1 / 4, 1 / 3, 5 / 12, 1 / 2, 7 / 12, 2 / 3, or 3 / 4.

[0190] The positive electrode tab 14 extends from the straight portion 161, allowing each layer of positive conductive portion 111 to be relatively flat after bending and enabling a larger area of ​​stacking of each layer of positive conductive portion 111. This increases the area projected onto the positive electrode tab 14 in the first direction X, thus meeting the area requirements for welding the positive electrode tab 14 to the positive electrode post 41 or the first adapter piece 61. Similarly, the negative electrode tab 15 extends from the straight portion 161, allowing the negative conductive portion 121 to be relatively flat after bending and enabling a larger area of ​​stacking of each layer of negative conductive portion 121. This increases the area projected onto the negative electrode tab 15 in the first direction X, thus meeting the area requirements for welding the negative electrode tab 15 to the negative electrode post 42 or the second adapter piece 62.

[0191] Furthermore, the ratio of the size of the end connecting the positive electrode tab 14 to the main body 16 along the second direction Y to the size of the main body 16 is set in the range of 1 / 4 to 3 / 4. This ensures that the number of layers of the positive conductive portion 111 is appropriate, and the current-carrying area of ​​the positive electrode plate 11 is appropriate. This satisfies the current-carrying requirements without affecting the degree of size reduction of the positive electrode plate 11 in the first direction X due to too many layers of the positive conductive portion 111, and without causing material waste. Similarly, the ratio of the size of the end connecting the negative electrode tab 15 to the main body 16 along the second direction Y to the size of the main body 16 is set in the range of 1 / 4 to 3 / 4. This ensures that the number of layers of the negative conductive portion 121 is appropriate, and the current-carrying area of ​​the negative electrode tab 15 is appropriate. This satisfies the current-carrying requirements without affecting the degree of size reduction of the negative electrode tab 15 in the first direction X due to too many layers of the negative conductive portion 121, and without causing material waste.

[0192] In some embodiments of this application, such as Figures 12 to 14 As shown, the edge of the region of the main body 16 with the positive electrode tab 14 extending along the second direction Y coincides with the edge of the end face of the main body 16 along the second direction Y, and the positive electrode tab 14 is bent toward the opposite edge of the end face; and / or, the edge of the region of the main body 16 with the negative electrode tab 15 extending along the second direction Y coincides with the edge of the end face of the main body 16 along the second direction Y, and the negative electrode tab 15 is bent toward the opposite edge of the end face.

[0193] The root of the positive electrode tab 14 is positioned close to one end edge of the end face of the main body 16 along the second direction Y, and bends towards the other end. This allows a larger positive electrode tab 14 to be positioned in the space on the side of the main body 16 facing the end cap 21 along the first direction X, thus ensuring that the positive electrode tab 14 meets the welding area requirements with the positive electrode post 41 or the first adapter piece 61. The root of the negative electrode tab 15 is positioned close to one end edge of the end face of the main body 16 along the second direction Y, and bends towards the other end. This allows a larger negative electrode tab 15 to be positioned in the space on the side of the main body 16 facing the end cap 21 along the first direction X, thus ensuring that the negative electrode tab 15 meets the welding area requirements with the negative electrode post 42 or the second adapter piece 62.

[0194] In some embodiments of this application, such as Figure 12 As shown, in the same electrode assembly 1, the end of the positive electrode tab 14 connected to the main body 16 and the end of the negative electrode tab 15 connected to the main body 16 are provided near the same end edge of the main body 16 along the second direction Y.

[0195] Thus, in the same electrode assembly 1, the positive electrode tab 14 and the negative electrode tab 15 are offset towards the same side of the end face of the main body 16 along the second direction Y, and their bending directions are consistent. Bending in the same direction reduces the risk of positional displacement of the tabs during the welding process, and reduces problems such as incomplete welding or breakage caused by tab misalignment. By unifying the bending direction, the design and adjustment steps of the welding fixture are simplified, and production efficiency is improved. Bending the positive and negative electrodes in the same direction reduces the risk of uneven stress on the electrode sheets caused by directional differences, reduces wrinkles or damage to the electrode sheets or separators caused by tension differences during the winding process, and helps to accurately control the center distance of the tabs, meeting the stringent requirements of the winding process for tab alignment.

[0196] In some embodiments of this application, such as Figure 12 As shown, there are two electrode assemblies 1 arranged along the second direction Y. The positive electrode tabs 14 of the two electrode assemblies 1 are bent towards each other along the second direction Y. The negative electrode tabs 15 of the two electrode assemblies 1 are bent towards each other along the second direction Y.

[0197] This arrangement brings the two positive electrode tabs 14 close together, facilitating connection to the same first adapter piece 61 or the same positive electrode post 41, and also brings the two negative electrode tabs 15 close together, facilitating connection to the same second adapter piece 62 or the same negative electrode post 42. The layout is reasonable and simplifies the process.

[0198] In some embodiments of this application, such as Figure 12 As shown, the positive electrode tabs 14 of the two electrode assemblies 1 are arranged opposite each other in the second direction Y, and the negative electrode tabs 15 of the two electrode assemblies 1 are arranged opposite each other in the second direction Y.

[0199] It should be noted that "the positive electrode tabs 14 of the two electrode assemblies 1 are arranged opposite each other in the second direction Y" means that the projections of the positive electrode tabs 14 of the two electrode assemblies 1 in the second direction Y have overlapping portions; "the negative electrode tabs 15 of the two electrode assemblies 1 are arranged opposite each other in the second direction Y" means that the projections of the negative electrode tabs 15 of the two electrode assemblies 1 in the second direction Y have overlapping portions. For example, as... Figure 12 As shown, the projections of the positive electrode tabs 14 of the two electrode assemblies 1 in the second direction Y completely overlap, and the projections of the negative electrode tabs 15 of the two electrode assemblies 1 in the second direction Y completely overlap.

[0200] This configuration simplifies the structure of the first adapter piece 61 or the positive terminal 41 connected to the two positive terminals 14, for example, as... Figure 10 As shown, the first adapter plate 61 can be a regular square plate with a small size, which simplifies the manufacturing process. Similarly, this arrangement simplifies the structure of the second adapter plate 62 or the negative terminal 42 connected to the two negative terminal tabs 15, for example, as... Figure 10As shown, the second adapter plate 62 can be a regular square plate with a small size, which helps to simplify the manufacturing process.

[0201] In some embodiments of this application, such as Figure 3 and Figure 10 As shown, two opposing positive electrode tabs 14 are connected to the positive electrode post 41 provided on the end cover 21 through the same first adapter piece 61; two opposing negative electrode tabs 15 are connected to the negative electrode post 42 provided on the end cover 21 through the same second adapter piece 62.

[0202] In this way, the two electrode assemblies 1 are connected in parallel and connected to the pole by the first adapter piece 61 and the second adapter piece 62, which reduces the number of parts, saves costs, reduces processes, and helps to improve production efficiency.

[0203] In some embodiments of this application, such as Figure 12 and Figure 13 As shown, two opposite positive electrode tabs 14 are stacked and welded together; two opposite negative electrode tabs 15 are stacked and welded together.

[0204] In this way, the two opposing positive electrode tabs 14 are welded together, and the two opposing negative electrode tabs 15 are welded together, improving the reliability of the parallel connection of the two electrode assemblies 1.

[0205] In some embodiments of this application, such as Figure 14 As shown, there is a gap between the two opposing positive electrode tabs 14; there is a gap between the two opposing negative electrode tabs 15.

[0206] This arrangement, with the two positive electrode tabs 14 spaced apart and the two negative electrode tabs 15 spaced apart, reduces the overlap of current paths between the tabs, lowers the risk of excessively high local current density, and thus alleviates polarization. Furthermore, by controlling the tab arrangement, the effective current transmission path is shortened, indirectly reducing the battery's internal resistance.

[0207] In some embodiments of this application, such as Figure 13 As shown, the number of layers of the positive electrode conductive portion 111 is in the range of 10 to 50, and the maximum size of the positive electrode tab 14 along the first direction X is in the range of 0.2 mm to 1 mm; and / or, the number of layers of the negative electrode conductive portion 121 is in the range of 10 to 50, and the maximum size H of the negative electrode tab 15 along the first direction X is in the range of 0.2 mm to 1 mm.

[0208] For example, the positive conductive portion 111 is made of aluminum or copper. The number of layers of the positive conductive portion 111 and / or the negative conductive portion 121 can be, but is not limited to, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, and 50. The maximum dimensions of the positive electrode tab 14 and / or the negative electrode tab 15 along the first direction X can be, but are not limited to, 0.2mm, 0.25mm, 0.3mm, 0.35mm, 0.4mm, 0.45mm, 0.5mm, 0.55mm, 0.6mm, 0.65mm, 0.7mm, 0.75mm, 0.8mm, 0.85mm, 0.9mm, 0.95mm, and 1mm.

[0209] In this embodiment of the application, by eliminating the converging portion of the positive electrode tab 14 and the negative electrode tab 15, the dimensions of the positive electrode tab 14 and the negative electrode tab 15 along the first direction X can be reduced to 0.2mm to 1mm, thereby reducing the space occupied by the tabs in the first direction X and improving the volumetric energy density of the battery cell 20.

[0210] In some embodiments of this application, laser welding is used as the welding method.

[0211] For example, the first adapter piece 61 is laser-welded to the positive electrode tab 14. The second adapter piece 62 is laser-welded to the negative electrode tab 15.

[0212] For example, the first adapter piece 61 and the positive electrode post 41 are laser-welded, which can be done by a through-welding method from the outside of the end cover 21 inwards. The second adapter piece 62 and the negative electrode post 42 are laser-welded, which can be done by a through-welding method from the outside of the end cover 21 inwards. In this way, solder marks are formed on the end faces of the positive electrode post 41 and the negative electrode post 42 facing away from the receiving cavity.

[0213] For example, the positive electrode tab 14 and the positive electrode post 41 are laser-welded, and the positive electrode tab 14 and the positive electrode post 41 can be welded by a through-welding method from the outside of the end cover 21 inward. The negative electrode tab 15 and the negative electrode post 42 are laser-welded, and the negative electrode tab 15 and the negative electrode post 42 can be welded by a through-welding method from the outside of the end cover 21 inward. In this way, solder marks are formed on the end faces of the positive electrode post 41 and the negative electrode post 42 facing away from the receiving cavity.

[0214] Of course, in some embodiments of this application, ultrasonic welding may be used. The specific welding position is similar to that of the laser welding position described above, and will not be repeated here.

[0215] In some embodiments of this application, such as Figure 10 As shown, each solder mark can be circular, square, or other shapes. The solder marks here include the aforementioned first solder mark 51, second solder mark 52, third solder mark 53, fourth solder mark 54, fifth solder mark, and sixth solder mark.

[0216] In some embodiments of this application, such as Figure 11 As shown, the end face of the positive electrode post 41 and / or the negative electrode post 42 facing away from the receiving cavity is formed with a groove 421 that is recessed toward the receiving cavity, and the bottom wall of the groove 421 is a position for laser welding.

[0217] By setting the groove 421, the thickness of the bottom wall of the groove 421 of the positive electrode post 41 and / or the negative electrode post 42 along the first direction X is smaller, that is, the positive electrode post 41 and / or the negative electrode post 42 is locally thinned, which makes it easier for the laser to pass through the bottom wall of the groove 421 from the outside and emit laser into the cavity for laser welding, thereby improving welding efficiency and welding effect.

[0218] The second aspect of this application provides a battery device 100, which includes a plurality of battery cells 20 provided in the first aspect.

[0219] Because the battery cell 20 provided in the first aspect has a high volumetric energy density, the battery device 100 including a plurality of battery cells 20 provided in the first aspect has a high volumetric energy density.

[0220] A third aspect of this application provides an energy storage device, which includes a plurality of battery cells 20 provided in the first aspect or a plurality of battery devices 100 provided in the second aspect, wherein the battery cells 20 or battery devices 100 are used to store or provide electrical energy.

[0221] Since the battery cell 20 provided in the first aspect has a high volumetric energy density and the battery device 100 provided in the second aspect has a high volumetric energy density, the energy storage device including a plurality of battery cells 20 provided in the first aspect or a plurality of battery devices 100 provided in the second aspect has a high volumetric energy density.

[0222] The fourth aspect of this application provides an electrical device that includes a plurality of battery cells 20 provided in the first aspect or a plurality of battery devices 100 provided in the second aspect, wherein the battery cells 20 or battery devices 100 are used to store or provide electrical energy.

[0223] Since the battery cell 20 provided in the first aspect has a high volumetric energy density and the battery device 100 provided in the second aspect has a high volumetric energy density, the power-consuming device including a plurality of battery cells 20 provided in the first aspect or a plurality of battery devices 100 provided in the second aspect has a high volumetric energy density.

[0224] The following describes specific examples of some embodiments of this application with reference to the accompanying drawings.

[0225] As a specific example, a cell structure (cell 20) is provided, including a casing (casing 2) and a bare cell (electrode assembly 1) disposed within the casing. After the electrodes (positive electrode 11 and negative electrode 12) of the bare cell are wound, the tabs (positive electrode tab 14 and negative electrode tab 15) are in an upright state. The tabs are bent and flattened to the same side. High-temperature resistant adhesive tape (protective layer 3) is attached to the bottom of the tabs. Before the tabs are flattened, high-temperature resistant adhesive tape needs to be attached to the end face that does not protrude from the tabs. The high-temperature resistant adhesive tape can be made of materials such as polyimide adhesive tape, which can reduce the probability of burning the separator (isolation element 13) when the tabs are laser welded. After the tabs are smoothed out, they need to be fixed with adhesive tape (fixing piece 7). Fixing with adhesive tape can reduce the risk of the tabs opening up and causing poor soldering. The fixing position of the adhesive tape should avoid the current collector (first adapter piece 61 and second adapter piece 62) and the solder marks of the tabs. The adhesive tape needs to be fixedly adhered to the outer side of the main body of the bare cell (main body 16). U-shaped adhesive tape can be used for fixing, which can play a good fixing role. After the tabs are secured with adhesive tape, the current collector is placed on top of the tabs. Laser welding is used to connect the current collector to the tabs. The weld marks on the current collector and tabs must cover every conductive layer of the tabs (positive conductive part 111 or negative conductive part 121). After welding the current collector, the top cover (end cover 21) is placed on top of the bare cell. External laser welding is used to connect the terminals (positive terminal 41 and negative terminal 42) to the current collector. Finally, the top cover (end cover 21) and the part connected to the bare cell are placed together in the aluminum shell (shell 22), and the top cover and aluminum shell are welded together. The terminals of the top cover are divided into a sealing area, an adapter plate connection area, an external connection area, and a hollowed-out center (groove 421). The hollowed-out center facilitates laser penetration and connection with the current collector. The laser welding direction is from the outside to the inside. Metal impurities generated by laser welding are on the outside and will not enter the inside, reducing the probability of failure.

[0226] The casing has two bare cells. The ratio of the width of the tab (dimension along the first direction X) to the overall thickness (dimension along the first direction X) of each bare cell is less than 3 / 4. The two bare cells are paired and bound together, with the side without tabs in the middle. Then, the tabs of both bare cells are smoothed towards the middle tabless position. The tabs of the two bare cells of the same polarity are soldered together. The solder marks can be circular or square. At the same time, the solder marks of the current collector and the tabs must not coincide with the solder marks of the terminal post.

[0227] The casing has a bare battery cell. The ratio of the width of the bare battery cell's tab (the dimension along the first direction X) to the thickness of the bare battery cell as a whole (the dimension along the first direction X) is less than 3 / 4. The tabs are all smoothed towards the side without tabs.

[0228] The above embodiments are merely illustrative of the technical solutions of this application and are not intended to limit it. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. These modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application, and all should be covered within the scope of the specification of this application. In particular, as long as there is no structural conflict, the various technical features mentioned in the embodiments can be combined in any way.

Claims

1. A battery cell, characterized in that, include: The housing includes a housing having an opening on one side along a first direction and an end cap that closes the opening, with a receiving cavity formed between the end cap and the housing; At least one electrode assembly is disposed within the receiving cavity. The electrode assembly includes a positive electrode, a negative electrode, and a spacer sandwiched between the positive electrode and the negative electrode. The end of the positive electrode near the end cap extends beyond the spacer, and the portion of the positive electrode near the end cap extending beyond the spacer is bent to the same side to form a positive electrode tab. The end of the negative electrode near the end cap extends beyond the spacer, and the portion of the negative electrode near the end cap extending beyond the spacer is bent to the same side to form a negative electrode tab.

2. The battery cell according to claim 1, characterized in that, The electrode assembly is formed by winding a laminate including the positive electrode, the negative electrode, and the separator. The portion of the positive electrode sheet extending beyond the insulating member at the end near the end cap includes multiple positive conductive portions arranged sequentially and at intervals along the winding direction. These multiple positive conductive portions are independently bent towards the same side and stacked to form the positive electrode tab. The portion of the negative electrode sheet extending beyond the insulating member at the end near the end cap includes multiple negative conductive portions arranged sequentially at intervals along the winding direction. These multiple negative conductive portions are independently bent toward the same side and stacked to form the negative electrode tab.

3. The battery cell according to claim 1 or 2, characterized in that, The portion of the positive electrode sheet that does not extend beyond the separator along the first direction, the portion of the negative electrode sheet that does not extend beyond the separator along the first direction, and the separator are stacked to form a main body. A protective layer is provided between the end face of the main body facing the end cap and the positive electrode tab and between the main body and the negative electrode tab. The melting point of the protective layer is in the range of 300°C to 500°C.

4. The battery cell according to claim 3, characterized in that, The protective layer has an electrical insulating function.

5. The battery cell according to claim 3, characterized in that, The protective layer is bonded to the end face of the main body facing the end cap.

6. The battery cell according to claim 5, characterized in that, The protective layer includes at least one of polyethylene terephthalate adhesive paper, polyimide adhesive paper, polyethylene naphthalate adhesive paper, aramid paper, mica paper, ceramic fiber paper, and polytetrafluoroethylene adhesive paper.

7. The battery cell according to claim 3, characterized in that, The battery cell also includes a positive electrode post and a negative electrode post respectively disposed on the end cap. The positive electrode post is connected to the positive electrode tab via a first adapter piece. The first adapter piece is welded to the positive electrode post to form a first solder mark, and the first adapter piece is welded to the positive electrode tab to form a second solder mark. There is no overlap between the first solder mark and the second solder mark. The negative electrode post is connected to the negative electrode tab via a second adapter piece. The second adapter piece is welded to the negative electrode post to form a third solder mark. The second adapter piece is welded to the negative electrode tab to form a fourth solder mark. There is no overlap between the third solder mark and the fourth solder mark.

8. The battery cell according to any one of claims 4 to 6, characterized in that, The battery cell also includes a positive electrode post and a negative electrode post respectively disposed on the end cap. The positive electrode post is connected to the positive electrode tab via a first adapter piece. The first adapter piece is welded to the positive electrode post to form a first solder mark, and the first adapter piece is welded to the positive electrode tab to form a second solder mark. There is no overlap between the first solder mark and the second solder mark. The negative electrode post is connected to the negative electrode tab via a second adapter piece. The second adapter piece is welded to the negative electrode post to form a third solder mark. The second adapter piece is welded to the negative electrode tab to form a fourth solder mark. There is no overlap between the third solder mark and the fourth solder mark.

9. The battery cell according to claim 7, characterized in that, Projecting along the first direction, the orthographic projections of the first solder mark and the second solder mark all fall within the orthographic projection range of the protective layer corresponding to the positive electrode tab, and the orthographic projections of the third solder mark and the fourth solder mark all fall within the orthographic projection range of the protective layer corresponding to the negative electrode tab.

10. The battery cell according to claim 3, characterized in that, The battery cell also includes a positive electrode post and a negative electrode post respectively disposed on the end cap. The positive electrode post is directly welded to the positive electrode tab to form a fifth weld mark, and the negative electrode post is directly welded to the negative electrode tab to form a sixth weld mark. Projecting along the first direction, the orthographic projection of the fifth solder mark falls entirely within the orthographic projection range of the protective layer corresponding to the positive electrode tab, and the orthographic projection of the sixth solder mark falls entirely within the orthographic projection range of the protective layer corresponding to the negative electrode tab.

11. The battery cell according to any one of claims 4 to 6, characterized in that, The battery cell also includes a positive electrode post and a negative electrode post respectively disposed on the end cap. The positive electrode post is directly welded to the positive electrode tab to form a fifth weld mark, and the negative electrode post is directly welded to the negative electrode tab to form a sixth weld mark. Projecting along the first direction, the orthographic projection of the fifth solder mark falls entirely within the orthographic projection range of the protective layer corresponding to the positive electrode tab, and the orthographic projection of the sixth solder mark falls entirely within the orthographic projection range of the protective layer corresponding to the negative electrode tab.

12. The battery cell according to any one of claims 4 to 7, 9 and 10, characterized in that, Both the positive electrode tab and the negative electrode tab have a fixing member pressed against the side facing the end cap, and the fixing member is connected to the main body.

13. The battery cell according to claim 12, characterized in that, The melting point of the fastener is in the range of 300℃ to 500℃.

14. The battery cell according to claim 12, characterized in that, The fastener is made of insulating material.

15. The battery cell according to claim 12, characterized in that, The fastener is bonded to two surfaces of the main body that are opposite each other along a second direction perpendicular to the first direction; The positive electrode tab and the negative electrode tab are respectively bonded to their respective fixing components.

16. The battery cell according to any one of claims 13 to 15, characterized in that, The fastener includes at least one of polyethylene terephthalate adhesive paper, polyimide adhesive paper, polyethylene naphthalate adhesive paper, aramid paper, mica paper, ceramic fiber paper, and polytetrafluoroethylene adhesive paper.

17. The battery cell according to claim 2, characterized in that, The positive electrode sheet (within the first direction) and the negative electrode sheet (within the first direction) and the insulating member are stacked together to form a main body. The main body includes a straight portion stacked along a second direction and two corner portions respectively connected to the two ends of the straight portion along a third direction. The first direction, the second direction, and the third direction are mutually perpendicular. The positive electrode tab and the negative electrode tab are spaced apart along the third direction and both extend from the straight portion. Along the second direction, the ratio of the size of the end of the positive electrode tab that connects to the main body to the size of the main body is in the range of 1 / 4 to 3 / 4; Along the second direction, the ratio of the size of the end of the negative electrode tab that connects to the main body to the size of the main body is in the range of 1 / 4 to 3 / 4.

18. The battery cell according to claim 17, characterized in that, The portion of the main body from which the positive electrode tab extends, along one end edge in the second direction, coincides with one end edge of the end face of the main body along the second direction; the positive electrode tab bends toward the opposite end edge of that end face; and / or, The area of ​​the main body from which the negative electrode tab extends coincides with one end edge of the end face of the main body along the second direction, and the negative electrode tab bends toward the opposite end edge of the end face.

19. The battery cell according to claim 18, characterized in that, In the same electrode assembly, the end of the positive electrode tab that connects to the main body and the end of the negative electrode tab that connects to the main body are disposed near the same end edge of the main body along the second direction.

20. The battery cell according to any one of claims 17 to 19, characterized in that, The electrode assembly has two electrodes arranged along the second direction. The positive electrode tabs of the two electrode assemblies are bent towards each other along the second direction. The negative electrode tabs of the two electrode assemblies are also bent towards each other along the second direction.

21. The battery cell according to claim 19, characterized in that, The positive electrode tabs of the two electrode assemblies are arranged opposite each other in the second direction, and the negative electrode tabs of the two electrode assemblies are arranged opposite each other in the second direction.

22. The battery cell according to claim 21, characterized in that, The two opposing positive electrode tabs are connected to the positive electrode post located on the end cap via the same first adapter piece; The two opposing negative electrode tabs are connected to the negative electrode post located on the end cap via the same second adapter piece.

23. The battery cell according to claim 22, characterized in that, The two opposing positive electrode tabs are stacked and welded together; The two opposing negative electrode tabs are stacked and welded together.

24. The battery cell according to claim 22, characterized in that, There is a gap between the two opposing positive electrode tabs; There is a gap between the two opposing negative electrode tabs.

25. The battery cell according to claim 2, characterized in that, The number of layers of the positive conductive portion is in the range of 10 to 50, and the maximum dimension of the positive electrode tab along the first direction is in the range of 0.2 mm to 1 mm; and / or The number of layers of the negative electrode conductive part is in the range of 10 to 50, and the maximum size of the negative electrode tab along the first direction is in the range of 0.2 mm to 1 mm.

26. A battery device, characterized in that, It includes the battery cells according to any one of claims 1 to 25.

27. An energy storage device, characterized in that, The energy storage device includes a plurality of battery cells as described in any one of claims 1 to 25 or a plurality of battery devices as described in claim 26, wherein the battery cells or the battery devices are used to store or provide electrical energy.

28. An electrical appliance, characterized in that, The electrical device includes a plurality of battery cells as described in any one of claims 1 to 25 or a plurality of battery devices as described in claim 26, wherein the battery cells or the battery devices are used to store or provide electrical energy.

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