Battery cells, batteries and power consuming devices

Abstract

The present application provides a battery cell, a battery, and a power consumption device, and relates to the field of battery technology. The battery cell includes an electrode assembly, a first plate of the electrode assembly has a plurality of welds on one side in the width direction, the plurality of welds are spaced apart in the length direction of the first plate, the first plate has a winding start end and a winding end end, the plurality of welds is closest to the winding start end, the plurality of welds is closest to the winding end end, the first plate has a main body segment from the first weld to the second weld, the main body segment is evenly divided into a plurality of sub-segments with a length L, the total length of the welds of each sub-segment is equal to or greater than 5%*L, and 200mm≦L≦1200mm, thereby making the distribution of the welds formed by welding the first plate and the current collecting member more reasonable, reducing the internal resistance of the battery cell, meeting actual overcurrent needs, and improving the power performance of the battery cell.

Description

[Technical Field]

[0001] This application relates to the field of battery technology, and more particularly to battery cells, batteries, and power consuming devices. [Background technology]

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

[0003] In the development of battery technology, in addition to the safety performance of the battery, the power performance of the battery is also an issue that cannot be ignored, and conventional batteries have low power performance due to their high internal resistance, so how to improve the power performance of the battery has become an issue that needs to be solved urgently in the field of battery technology. Summary of the Invention

[0004] Embodiments of the present application provide a battery cell, a battery, and a power consuming device to improve the power performance of the battery.

[0005] In a first aspect, an embodiment of the present application provides a battery cell, the battery cell including an electrode assembly including a first electrode plate, wherein a plurality of welds are provided on one side in a width direction of the first electrode plate, and the plurality of welds are provided at intervals in a length direction of the first electrode plate; The electrode assembly has a winding structure, the first electrode plate includes a winding start end and a winding end end, the welded portion of the plurality of welds closest to the winding start end is a first welded portion, and the welded portion of the plurality of welds closest to the winding end end is a second welded portion, the first electrode plate includes a main body segment extending from an edge of the first welded portion close to the winding start end to an edge of the second welded portion close to the winding end end, the main body segment being equally divided into a plurality of sub-segments each having a length L, and the total length of the welded portions of each sub-segment is 5%*L or more, and 200 mm≦L≦1200 mm.

[0006] In the above technical solutions, the current collecting member and the electrode assembly are conventionally welded by laser continuous linear welding or pulse spot welding, with the welds having shapes such as X-shapes or rings. After the electrode plate is unfolded, it can be seen that the welds are dense in some sections along the length of the electrode plate, while the welds are sparse in other sections, meaning that the distribution of the welds on the electrode plate is not uniform. In sections with sparse welds, the effective weld length of the electrode plate (i.e., the total length of the welds in that section) is not sufficient to match the length of the electrode plate, resulting in low overcurrent capacity between the electrode plate and the current collecting member, high internal resistance of the battery cell, and reduced power performance of the battery cell. After welding one widthwise side of the current collecting member to the first plate, multiple welds are formed at intervals along the length of the first plate. The main body of the first plate, defined by the first weld near the winding start end and the second weld near the winding end, is divided into multiple equal-length subsegments, with the total length of the welds in each subsegment being at least 5% of the subsegment length. This allows for a more rational distribution of the welds formed by welding the first plate to the current collecting member, reduces the internal resistance of the battery cell, meets actual overcurrent needs, and improves the power performance of the battery cell. By setting the subsegment length between 200 mm and 1200 mm, the winding length of the first plate meets actual product needs and the battery cell has a high energy density.

[0007] In some embodiments of the first aspect of the present application, the absolute value of the difference in total length of the welds of any two of the sub-segments is 10 mm or less.

[0008] In the above technical solution, the absolute value of the difference in the total length of the welds between any two subsegments is controlled to within 10 mm, and the difference in the total length of the welds between each subsegment is minimized as much as possible, making the distribution of the welds more reasonable, helping to reduce the internal resistance of the battery cell, and reducing the difference in the overcurrent capacity of each subsegment, meeting actual overcurrent needs and improving the power performance of the battery cell. Controlling the absolute value of the difference in the total length of the welds between any two subsegments to within 10 mm is equivalent to keeping the error in the weld width of each subsegment to within 10 mm, and since it is acceptable for there to be an error in the total weld length between each subsegment, the difficulty of welding can be reduced.

[0009] In some embodiments of the first aspect of the present application, the total length of the welds of any two of the sub-segments is the same.

[0010] In the above technical solution, if the total length of the welds of any two sub-segments is the same, there is no difference in the total length of the welds of each sub-segment, making the distribution of the welds more reasonable, reducing the internal resistance of the battery cell as much as possible, and making the overcurrent capacity of each sub-segment the same, meeting the actual overcurrent needs and improving the power performance of the battery cell.

[0011] In some embodiments of the first aspect of the present application, the absolute value of the difference in the number of welds between any two of the sub-segments is 10 or less.

[0012] In the above technical solution, the absolute value of the difference in the number of welds between any two subsegments is controlled to within 10, and the difference in the total length of the welds between each subsegment is minimized, thereby making the distribution of welds more reasonable, helping to reduce the internal resistance of the battery cell, reducing the difference in the overcurrent capacity of each subsegment, meeting actual overcurrent needs, and improving the power performance of the battery cell. Controlling the absolute value of the difference in the number of welds between any two subsegments to within 10 is equivalent to allowing the number of welds in each subsegment to differ, and allowing for some error in the total weld length between each subsegment, thereby reducing the difficulty of welding.

[0013] In some embodiments of the first aspect of the present application, the number of welds in any two of the sub-segments is the same.

[0014] In the above technical solution, if the number of welds in any two sub-segments is the same, the difference in the total length of the welds in each sub-segment should be reduced as much as possible, making the distribution of the welds more reasonable, which is helpful in reducing the internal resistance of the battery cell, making the overcurrent capacity of each sub-segment the same, meeting the actual overcurrent needs, and improving the power performance of the battery cell.

[0015] In some embodiments of the first aspect of the present application, the first plate further includes a winding start segment that is continuous with the main body segment, and the winding start segment extends from the winding start end to an edge of the first weld that is close to the winding start end.

[0016] In the above technical solution, the winding start segment extends from the winding start end to the edge of the first welded portion that is closest to the winding start end; that is, the winding start segment is defined by the winding start end and the edge of the first welded portion that is closest to the winding start end; no welds are formed on the winding start segment, and there is no welding relationship between the winding start segment and the current collecting member. This facilitates welding the current collecting member to the electrode terminal to output electrical energy from the battery cell.

[0017] In some embodiments of the first aspect of the present application, the length of the winding start segment is A, and A≦L is satisfied.

[0018] In the above technical solution, in the length direction of the first plate, the distance between the winding start end and the first weld is shorter than the length of the characteristic segment, i.e., the length of the winding start segment where no weld is provided is shorter than the sub-segment where a weld is provided, so that the length of the section of the first plate where no weld is provided is not too long and stable output of electrical energy from the battery cell is ensured.

[0019] In some embodiments of the first aspect of the present application, the first plate further includes a winding end segment that is continuous with the main body segment, and the winding end segment extends from the winding end to an edge of the second weld that is close to the winding end.

[0020] In the above technical solution, the winding end segment extends from the winding end end to the edge of the second welded portion that is close to the winding end end; that is, the winding end segment is defined by the winding end end and the edge of the second welded portion that is close to the winding end end; no welds are provided on the winding end segment, and there is no welding relationship between the winding end segment and the corresponding current collecting member. This facilitates welding the current collecting member to the electrode terminal to output electrical energy from the battery cell.

[0021] In some embodiments of the first aspect of the present application, the length of the winding end segment is B, and B≦L is satisfied.

[0022] In the above technical solution, in the length direction of the first plate, the length of the winding end segment is shorter than the length of the sub-segments, i.e., the length of the winding start segment where no weld is provided is shorter than the sub-segments where welds are provided, so that the length of the section of the first plate where no weld is provided is not too long and stable output of electrical energy from the battery cell is ensured.

[0023] In some embodiments of the first aspect of the present application, in two adjacent turns of the first electrode plate, the number of welds in one turn closer to the winding center of the electrode assembly is smaller than the number of welds in one turn away from the winding center.

[0024] In the above technical solution, for a wound-type electrode assembly, the length of one turn close to the winding center of two adjacent first plates is smaller than the length of one turn away from the winding center, and during welding, the number of welds formed in one turn close to the winding center of the wound-type electrode assembly is smaller than the number of welds in one turn away from the winding center, so that the length of the first plate in each turn and the number of welds corresponding to the first plate in each turn match the total length of the welds, making the distribution of the welds more reasonable, reducing the internal resistance of the battery cell, meeting actual overcurrent needs, and improving the power performance of the battery cell.

[0025] In some embodiments of the first aspect of the present application, the battery cell further includes a housing, an end cover assembly, and a current collecting member, the housing is used to accommodate the electrode assembly and has an opening, the end cover assembly includes an end cover for covering the opening and an electrode terminal attached to the end cover, the current collecting member is located between the end cover and the electrode assembly and is used to connect a tab portion of the electrode assembly to the electrode terminal, the tab portion is formed by winding an uncoated region of the first electrode plate, and at least a portion of the current collecting member is welded to the tab portion to form the plurality of welds.

[0026] In the above technical solution, at least a portion of the current collecting member is welded to the tab portion to form a plurality of welds, and in the longitudinal direction of the first plate, a body portion defined by a first weld portion near the winding start end and a second weld portion near the winding end end of the first plate is divided into a plurality of sub-segments of equal length, and the total length of the welds in each sub-segment is 5% or more of the length of the sub-segment, thereby making the distribution of the welds formed by welding the first plate and the current collecting member more reasonable, reducing the internal resistance of the battery cell, meeting actual overcurrent needs, and improving the power performance of the battery cell.

[0027] In some embodiments of the first aspect of the present application, the first electrode plate further includes a winding start segment extending from the winding start end to an edge of the first weld that is close to the winding start end, an uncoated region of the main body segment being wound to form a first portion, and an uncoated region of the winding start segment being wound to form a second portion, the second portion being located radially inward of the first portion, the current collecting member including a first current collecting portion and a second current collecting portion that are arranged successively in the radial direction, the first current collecting portion being opposed to the first portion in the width direction of the first electrode plate and welded to the first portion to form the plurality of welds, and the second current collecting portion being opposed to the second portion in the width direction of the first electrode plate and welded to the electrode terminal.

[0028] In the above technical solution, a first portion formed by winding the uncoated region of the main body segment is welded to a first current collecting portion of the current collecting member, thereby achieving electrical connection between the electrode assembly and the current collecting member. The winding start segment extends from the winding start end to the edge of the first welded portion closest to the winding start end, i.e., the winding start segment is defined by the winding start end and the edge of the first welded portion closest to the winding start end. No weld is formed in the winding start segment, i.e., there is no welded relationship between the second portion formed by winding the uncoated region of the winding start segment and the current collecting member, and no weld mark is formed on the second current collecting portion facing the second portion, facilitating welding between the current collecting member and the electrode terminal via the second current collecting portion, thereby outputting electrical energy from the battery cell.

[0029] In some embodiments of the first aspect of the present application, the first electrode plate further includes a winding end segment extending from the winding end end to an edge of the second welded portion that is closer to the winding end end, wherein an uncoated region of the main body segment is wound to form a first portion, and an uncoated region of the winding end segment is wound to form a third portion, the third portion being located radially outward from the first portion, the current collecting member including a first current collecting portion and a third current collecting portion that are arranged successively in the radial direction, the first current collecting portion being opposed to the first portion in the width direction of the first electrode plate and welded to the first portion to form the plurality of welds, and the third current collecting portion being opposed to the third portion in the width direction of the first electrode plate and welded to the electrode terminal.

[0030] In the above technical solution, a first portion formed by winding the uncoated region of the main body segment is welded to a first current collecting portion of the current collecting member, thereby achieving an electrical connection between the electrode assembly and the current collecting member. The winding end segment extends from the winding end to the edge of the second welded portion closest to the winding end, i.e., the winding end segment is defined by the winding end and the edge of the second welded portion closest to the winding end, and no weld is formed in the winding end segment, i.e., there is no welding relationship between the current collecting member and a third portion formed by winding the uncoated region of the winding end segment, and no welding mark is formed on the third current collecting portion opposite the third portion, facilitating welding between the current collecting member and the electrode terminal via the third current collecting portion to output electrical energy from the battery cell.

[0031] In a second aspect, an embodiment of the present application provides a battery including a battery cell provided by an embodiment of the first aspect.

[0032] In the above technical solution, in a battery including a battery cell provided according to an embodiment of the first aspect, a main body portion of a first electrode plate of the battery cell, which is defined by a first welded portion near the winding start end and a second welded portion near the winding end end, is divided into a plurality of sub-segments of equal length, and the total length of the welds in each sub-segment is 5% or more of the length of the sub-segment, thereby making the distribution of the welds formed by welding the first electrode plate and the current collecting member more reasonable, reducing the internal resistance of the battery cell, meeting actual overcurrent needs, and improving the power performance of the battery.

[0033] In a third aspect, embodiments of the present application provide a power consuming device including a battery provided by an embodiment of the second aspect.

[0034] In the above technical solution, the power consumption device adopts a battery provided by an embodiment of the second aspect, and the main body of the first electrode plate of the battery cell, defined by a first welded portion near the winding start end and a second welded portion near the winding end end, is divided into a plurality of sub-segments of equal length, and the total length of the welds in each sub-segment is 5% or more of the length of the sub-segment, thereby making the distribution of the welds formed by welding the first electrode plate and the current collecting member more reasonable, reducing the internal resistance of the battery, meeting actual overcurrent needs, and improving the power performance of the battery. [Brief explanation of the drawings]

[0035] In order to more clearly explain the technical solutions of the embodiments of the present application, the drawings that need to be used in the embodiments will be briefly described below. However, the following drawings only illustrate some embodiments of the present application and should not be considered as limiting the scope. It should be understood that those skilled in the art can further derive other related drawings based on these drawings without any creative efforts. [Figure 1] 1 is a structural schematic diagram of a vehicle provided in accordance with some embodiments of the present application. [Figure 2] 1 is a structural schematic diagram of a battery provided in some embodiments of the present application. [Figure 3] FIG. 1 is an exploded view of a battery cell provided in accordance with some embodiments of the present application. [Figure 4] 1 is a structural schematic diagram of an electrode assembly provided in some embodiments of the present application. [Figure 5] FIG. 2 is an exploded view of a first electrode plate provided in accordance with some embodiments of the present application. [Figure 6] FIG. 2 is a dimensional schematic diagram of a first electrode plate in an expanded state provided in some embodiments of the present application. [Figure 7] 1 is a structural schematic diagram of an electrode assembly provided in accordance with some other embodiments of the present application. [Figure 8] FIG. 2 is an exploded view of a first electrode plate provided in accordance with some other embodiments of the present application. [Figure 9]FIG. 2 is a dimensional schematic diagram of a first electrode plate in an expanded state provided in some other embodiments of the present application. [Figure 10] FIG. 10 is an exploded view of a first electrode plate provided in accordance with still further embodiments of the present application. [Figure 11] FIG. 10 is a dimensional schematic diagram of a first electrode plate in an expanded state provided according to still other embodiments of the present application. [Figure 12] 1 is an electrical schematic diagram of an electrode assembly provided in accordance with yet another embodiment of the present application. [Figure 13] 1 is a structural schematic diagram of an electrode assembly provided in accordance with still further embodiments of the present application. [Figure 14] 2 is a schematic diagram of a current collecting member after welding provided by some embodiments of the present application. FIG. [Figure 15] 3 is a schematic diagram of a current collecting member after welding provided by some other embodiments of the present application. FIG. [Figure 16] 10 is a schematic diagram of a current collecting member after welding provided by still further some embodiments of the present application. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0036] In order to make the objectives, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions of the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, but not all of the embodiments. In general, the assemblies of the embodiments of the present application described and illustrated in the drawings herein can be arranged and designed in a variety of different configurations.

[0037] Therefore, the detailed description of the embodiments of the present application provided below with reference to the drawings is not intended to limit the scope of the claims of the present application, but merely illustrates specific embodiments of the present application. All other embodiments obtained by those skilled in the art based on the embodiments of the present application without making creative efforts fall within the scope of protection of the present application.

[0038] As needs to be explained, the embodiments and features of the embodiments of the present application can be combined with each other unless they conflict.

[0039] It should be noted that like reference numbers and letters indicate like items in the following drawings, so that once an item is defined in one drawing, it need not be further defined or interpreted in subsequent drawings.

[0040] In describing the embodiments of the present application, it is necessary to explain that the orientations and positional relationships indicated are based on the orientations and positional relationships shown in the drawings, or are the orientations and positional relationships that are normally placed when the products of the present application are used, or are the orientations and positional relationships that are normally understood by those skilled in the art, and are merely for the purpose of making the present application easier to explain and simplifying the description, and do not indicate or suggest that the devices or elements have a specific orientation, or are configured and operated in a specific orientation, and therefore should not be understood as limiting the present application. Furthermore, terms such as "first," "second," and "third" are merely used for the purpose of distinction and description, and should not be understood as indicating or suggesting relative importance.

[0041] Currently, in view of the trend of market development, the application of power batteries is becoming more and more widespread. Power batteries are not only applied to energy storage power supply systems such as hydroelectric power, thermal power, wind power and solar thermal power plants, but also widely used in electric vehicles such as electric bicycles, electric motorcycles and electric cars, as well as in many fields such as military equipment and aerospace. With the expansion of the application fields of power batteries, the market demand for them is becoming increasingly large.

[0042] As noted by the inventors, a battery cell includes a housing, an end cover assembly, and an electrode assembly, the end cover assembly being covered on the housing and providing a sealed space for the electrode assembly and electrolyte, electrical energy of the electrode assembly can be extracted from the housing through electrode terminals of the end cover assembly, the electrode assembly being welded to a current collecting member through a tab, and the electrode terminals being electrically connected to the current collecting member so as to extract electrical energy from the battery, the electrode assembly including a plate, the plate having a coated area where an active material layer is coated and an uncoated area where the active material layer is not coated, the uncoated area of ​​the plate being wound to form a tab portion, and the current collecting member being welded to the tab portion to form multiple welds.

[0043] For a winding-type full-tab electrode assembly, the tab needs to be flattened before being welded to the current collecting member. Conventional current collecting members and electrode assemblies are welded by laser continuous linear welding or pulse spot welding, resulting in welds with shapes such as X-shaped or circular. After unfolding the electrode plate, it can be seen that along the length of the electrode plate, some sections have dense welds, while others have sparse welds, resulting in an uneven distribution of welds on the electrode plate. In sections with sparse welds, the effective weld length of the electrode plate (i.e., the total length of the welds in that section) is insufficient to match the length of the electrode plate, resulting in low overcurrent capability between the electrode plate and the current collecting member, high internal resistance of the battery cell, and reduced power performance of the battery cell.

[0044] In light of this, and to solve the problem of high internal resistance and low overcurrent capability of battery cells due to the irrational distribution of weld positions between the electrode plates and the current collecting members, the inventors conducted extensive research and designed a battery cell in which the main body defined by the first weld near the winding start end and the second weld near the winding end end of the first electrode plate is divided into a number of sub-segments of equal length, and the total length of the welds in each sub-segment is set to 5% or more of the length of the sub-segment. This makes the distribution of the welds formed by welding the first electrode plate and the current collecting members more rational, reduces the internal resistance of the battery cell, meets actual overcurrent needs, and improves the power performance of the battery cell.

[0045] The technical solutions described in the embodiments of the present application are applied to batteries and battery-powered power-consuming devices.

[0046] The power consuming devices may be vehicles, mobile phones, portable devices, laptops, boats, spacecraft, electric toys, power tools, etc. The vehicles may be gasoline-powered automobiles, gas-powered automobiles, or new energy automobiles. The new energy automobiles may be pure electric vehicles, hybrid automobiles, extended-range electric vehicles, etc. The spacecraft may include airplanes, rockets, space shuttles, spaceships, etc. The electric toys include game consoles, electric car toys, electric car toys, electric car toys, electric car toys, and other stationary or mobile electric toys. The power tools include electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, metal cutting power tools such as concrete vibrators and electric planers, polishing power tools, mounting power tools, and railway power tools. In the embodiments of the present application, the power consuming devices are not particularly limited.

[0047] In the following embodiments, for ease of explanation, a case will be described in which the power consuming device is a vehicle.

[0048] Referring to Fig. 1, Fig. 1 is a structural schematic diagram of a vehicle 1000 provided according to some embodiments of the present application. A battery 100 is provided inside the vehicle 1000, and the battery 100 may be provided at the bottom, front, or rear of the vehicle 1000. The battery 100 can be used to power the vehicle 1000, for example, the battery 100 can be an operating power source for the vehicle 1000.

[0049] The vehicle 1000 may further include a controller 200 and a motor 300, where the controller 200 is used to control the battery 100 to power the motor 300, for example, to meet the needs of the vehicle 1000 for starting, navigation, and operating power while driving.

[0050] In some embodiments of the present application, the battery 100 can be used not only as an operating power source for the vehicle 1000, but also as a driving power source for the vehicle 1000, providing driving power to the vehicle 1000 in place of, or in place of, gasoline or natural gas.

[0051] 2, which is a structural schematic diagram of a battery 100 provided according to some embodiments of the present application. The battery 100 includes a housing 10 and a battery cell 20 housed within the housing 10.

[0052] The housing 10 is used to provide a storage space 11 for the battery cells 20. In some embodiments, the housing 10 may include a first portion 12 and a second portion 13, which are covered with each other to define the storage space 11 for storing the battery cells 20. Of course, the connection between the first portion 12 and the second portion 13 may be sealed with a sealing member (not shown), which may be a sealing ring, a sealant, or the like.

[0053] The first section 12 and the second section 13 may have various shapes, such as a rectangular parallelepiped or a cylindrical shape. The first section 12 may have a hollow structure with one open end and a storage section for storing the battery cells 20, and the second section 13 may also have a hollow structure with one open end and a storage section for storing the battery cells 20, with the open side of the second section 13 being covered by the open side of the first section 12, thereby forming the housing 10 having an enclosed space. Of course, the first section 12 may have a hollow structure with one open end and a storage section for storing the battery cells 20, and the second section 13 may have a plate-like structure, and the second section 13 may be covered by the open side of the first section 12, thereby forming the housing 10 having an enclosed space.

[0054] The battery 100 may include one or more battery cells 20. If there are multiple battery cells 20, the multiple battery cells 20 may be connected in series, parallel, or series-parallel, and a series-parallel connection includes both series and parallel connections of the multiple battery cells 20. The multiple battery cells 20 may be directly connected in series, parallel, or series-parallel, and then the entire configuration of the multiple battery cells 20 may be housed in the housing 10. Of course, the multiple battery cells 20 may first be connected in series, parallel, or series-parallel to form a battery module, and the multiple battery modules may be further connected in series, parallel, or series-parallel to form a whole and housed in the housing 10. The battery cells 20 may be cylindrical, flat, rectangular, or have other shapes. FIG. 2 exemplarily shows a case where the battery cells 20 are cylindrical.

[0055] In some embodiments, the battery 100 may further include bus bar members (not shown), and electrical connection between the multiple battery cells 20 can be achieved via the bus bar members, thereby realizing a series connection, a parallel connection, or a series-parallel connection of the multiple battery cells 20.

[0056] 3, which is an exploded view of a battery cell 20 provided according to some embodiments of the present application. The battery cell 20 may include a housing 21, an electrode assembly 22, and an end cover assembly 23. The housing 21 has an opening 211, the electrode assembly 22 is housed within the housing 21, and the end cover assembly 23 is used to cover the opening 211.

[0057] The housing 21 may have various shapes, such as a cylinder or a rectangular parallelepiped. The shape of the housing 21 can be determined depending on the specific shape of the electrode assembly 22. For example, if the electrode assembly 22 has a cylindrical structure, the housing 21 may have a cylindrical structure, and if the electrode assembly 22 has a rectangular parallelepiped structure, the housing 21 may have a rectangular parallelepiped structure. Figure 3 exemplarily shows a case where the housing 21 and the electrode assembly 22 are cylindrical.

[0058] The housing 21 may be made of various materials such as copper, iron, aluminum, stainless steel, and aluminum alloy, and the embodiment of the present application is not particularly limited thereto.

[0059] The electrode assembly 22 may include a positive electrode plate (not shown), a negative electrode plate (not shown), and a separator (not shown).

[0060] The positive electrode plate includes a positive electrode current collector and a positive electrode active material layer. The positive electrode active material layer is coated on the surface of the positive electrode current collector. The positive electrode current collector without the positive electrode active material layer protrudes from the positive electrode current collector coated with the positive electrode active material layer, and the positive electrode current collector without the positive electrode active material layer is used as a positive electrode tab. In the case of a lithium-ion battery, the positive electrode current collector may be made of aluminum, and the positive electrode active material may be lithium cobalt oxide, lithium iron phosphate, ternary lithium, or lithium manganese oxide. The negative electrode plate includes a negative electrode current collector and a negative electrode active material layer. The negative electrode active material layer is coated on the surface of the negative electrode current collector. The negative electrode current collector without the negative electrode active material layer protrudes from the negative electrode current collector coated with the negative electrode active material layer, and the negative electrode current collector without the negative electrode active material layer is used as a negative electrode tab. The negative electrode current collector may be made of copper, and the negative electrode active material may be carbon or silicon.

[0061] The electrode assembly 22 may have a wound structure formed by winding a positive electrode plate, a separator, and a negative electrode plate. The electrode assembly 22 may further include a positive electrode tab (not shown) and a negative electrode tab (not shown). The positive electrode tab may be a positive electrode current collector in the positive electrode plate that is not coated with a positive electrode active material layer, and the negative electrode tab may be a negative electrode current collector in the negative electrode plate that is not coated with a negative electrode active material layer.

[0062] The end cover assembly 23 is used to cover the opening 211 of the housing 21 to form a sealed storage cavity (not shown), which is used to store the electrode assembly 22. The storage cavity is also used to store an electrolyte such as an electrolytic solution. The end cover assembly 23 is used as a member that outputs electrical energy for the electrode assembly 22, and electrode terminals 232 on the end cover assembly 23 are used to electrically connect to the electrode assembly 22, i.e., the electrode terminals 232 are electrically connected to tabs of the electrode assembly 22.

[0063] It should be noted that the number of openings 211 in the housing 21 may be one or two. When the housing 21 has one opening 211, the end cover assembly 23 may also be one, and two electrode terminals 232 may be provided on the end cover assembly 23. The two electrode terminals 232 are used to electrically connect to the positive and negative tabs of the electrode assembly 22, respectively, and the two electrode terminals 232 on the end cover assembly 23 are the positive electrode terminal 232 and the negative electrode terminal 232, respectively. As shown in FIG. 3 , when the housing 21 has two openings 211, for example, the two openings 211 are provided on opposite sides of the housing 21, and the number of end cover assemblies 23 may also be two, and the two end cover assemblies 23 are each covered by the two openings 211 of the housing 21. In this case, the electrode terminal 232 in one end cover assembly 23 may be a positive electrode terminal for electrically connecting to the positive electrode tab of the electrode assembly 22, and the electrode terminal 232 in the other end cover assembly 23 may be a negative electrode terminal for electrically connecting to the negative electrode plate of the electrode assembly 22.

[0064] 4, 5, and 6, Fig. 4 is a structural schematic diagram of an electrode assembly 22 provided according to some embodiments of the present application, Fig. 5 is an exploded view of a first electrode plate 221 provided according to some embodiments of the present application, and Fig. 6 is a dimensional schematic diagram of the first electrode plate provided according to some embodiments of the present application in an exploded state. A battery cell 20 includes an electrode assembly 22. The electrode assembly 22 includes a first electrode plate 221, and a plurality of welds 222 are provided on one side of the first electrode plate in a width direction X, and the plurality of welds 222 are provided at intervals in a length direction Y of the first electrode plate. The electrode assembly 22 has a winding structure, and the first electrode plate 221 includes a winding start end 223 and a winding end 224. Of the multiple welds 222, the one closest to the winding start end 223 is the first weld 222a, and the one closest to the winding end 224 is the second weld 222b. The first electrode plate 221 includes a main body segment 225 extending from the edge of the first weld 222a closest to the winding start end 223 to the edge of the second weld 222b closest to the winding end 224. The main body segment 225 is equally divided into multiple sub-segments 2251 each having a length L. The total length of the welds 222 of each sub-segment 2251 is equal to or greater than 5%*L, and 200 mm≦L≦1200 mm.

[0065] In the width direction X of the first electrode plate, the first electrode plate 221 includes a coated region 2211 coated with an active material layer and an uncoated region 2212 not coated with an active material layer. The first electrode plate 221 may be a positive electrode plate or a negative electrode plate. The electrode assembly 22 further includes a second electrode plate. If the first electrode plate 221 is a positive electrode plate and the coating region 2211 is coated with a positive electrode active material, the second electrode plate is a negative electrode plate. If the first electrode plate 221 is a negative electrode plate and the coating region 2211 is coated with a negative electrode active material, the second electrode plate is a positive electrode plate. In an embodiment of a wound electrode assembly in which the tabs of the electrode assembly 22 are full tabs, the tabs of the first electrode plate 221 and the second electrode plate are located at both axial ends of the electrode assembly 22, respectively.

[0066] Regarding the winding start end 223, when the electrode assembly 22 is formed by winding the first electrode plate 221, the winding start end 223 is used as the winding start point of the first electrode plate 221, and after the winding is completed, the winding start end 223 is located at the innermost position of the electrode assembly 22 relative to other parts of the first electrode plate 221.

[0067] Regarding the winding end 224, when the electrode assembly 22 is formed by winding the first electrode plate 221, the winding end 224 is used as the winding end point of the first electrode plate 221, and after the winding is completed, the winding end 224 is located at the outermost position of the electrode assembly 22 relative to other parts of the first electrode plate 221.

[0068] When the first electrode plate 221 is in the deployed state, the length of the weld 222 refers to the distance between the edge of the weld 222 closest to the winding start end 223 and the edge of the weld 222 closest to the winding end end 224, i.e., the dimension of the weld 222 in the length direction Y of the first electrode plate. The total length of the welds 222 of the subsegment 2251 refers to the sum of the lengths of all the welds 222 located in the subsegment 2251.

[0069] Each sub-segment 2251 may include one or more welds 222, and in embodiments in which each sub-segment 2251 includes multiple welds 222, the multiple welds 222 may be evenly spaced apart or may be non-uniformly spaced apart.

[0070] The length of the body segment 225 should be equal to or greater than the sum of the lengths of the two sub-segments 2251 , that is, the body segment 225 is evenly divided into at least two sub-segments 2251 .

[0071] During actual welding, the flattened tab of the first electrode plate 221 of the electrode assembly 22 is divided radially into multiple regions surrounding the winding center of the electrode assembly 22, each region including at least one turn of the first electrode plate 221, each region may include one or more sub-segments 2251, and each sub-segment 2251 may be wound at least one turn.

[0072] 4, the tab portion of the first electrode plate 221 is divided into six concentric regions surrounding the winding center hole 226 of the electrode assembly 22, and defined from the inside to the outside as a first region 226a, a second region 226b, a third region 226c, a fourth region 226d, a fifth region 226e, and a sixth region 226f. In FIG. 4, the six regions are separated by a first ring 227a, a second ring 227b, a third ring 227c, a fourth ring 227d, and a fifth ring 227e, respectively, which are indicated by dotted lines, and each region includes one subsegment 2251.

[0073] The "inside to outside" described herein refers to the center of winding of the electrode assembly 22, and the one closer to the center of winding is located inside the one further from the center of winding.

[0074] In the verification of the battery cell, the discharge internal resistance of the battery within 0.1 seconds is defined as the ohmic resistance. The magnitude of the ohmic resistance affects the internal resistance during charge and discharge of the battery cell 20 and the overcurrent capability during charge and discharge. In order to test the effect of the ratio of the total length of the welded portion 222 of the subsegment 2251 to the length of the subsegment 2251 on the internal resistance during charge and discharge of the battery cell 20 and the overcurrent capability during charge and discharge, the following test was performed.

[0075] Test conditions: The length of the subsegment was 800 mm. The test ambient temperature was 25°C. SOC (state of charge) refers to the ratio of the remaining capacity of a battery after a certain period of use or after a long period of unused storage to its fully charged capacity. It is often expressed as a percentage. Its value ranges from 0 to 1, with SOC = 0 indicating a fully discharged battery and SOC = 1 indicating a fully charged battery. In this application, the ohmic internal resistance and total internal resistance of the battery cell 20 were tested using an SOC of 0.5 as an example. To obtain the total internal resistance of the battery cell 20, a direct current internal resistance (DCIR) test was employed. The total internal resistance of the battery cell 20 includes two components: ohmic internal resistance and polarization internal resistance. The DCIR test is a measurement method that takes into account both resistance components, also known as dynamic internal resistance.

[0076] [Table 1]

[0077] As can be seen from the above test results, when the ratio of the total length of the welds 222 of the sub-segment 2251 to the length of the sub-segment 2251 is 3% to 5%, the ohmic internal resistance of the battery cell 20 and the total internal resistance of the battery both gradually decrease as the ratio of the total length of the welds 222 of the sub-segment 2251 to the length of the sub-segment 2251 increases; when the ratio of the total length of the welds 222 of the sub-segment 2251 to the length of the sub-segment 2251 is 5% or more, the ohmic internal resistance of the battery cell 20 and the total internal resistance of the battery both tend to be stable. Therefore, in the present application, the total length of the welds 222 of the sub-segment 2251 is 5% or more of the length of the sub-segment 2251, so that the battery cell 20 has small charge / discharge internal resistance and strong charge / discharge overcurrent capability.

[0078] In the prior art, the current collecting member 24 (shown in FIG. 3) and the electrode assembly 22 are welded by laser continuous linear welding or pulse spot welding, resulting in welds with shapes such as X-shaped or circular. After the electrode plate is unfolded, it can be seen that the welds are dense in some sections along the length of the electrode plate, while the welds are sparse in other sections, resulting in an uneven distribution of the welds on the electrode plate. In sections with sparse welds, the effective weld length of the electrode plate (i.e., the total length of the welds in that section) is insufficient to match the length of the electrode plate, resulting in a low overcurrent capacity between the electrode plate and the current collecting member 24, a high internal resistance of the battery cell, and reduced power performance of the battery cell 20. After the current collecting member 24 is welded to one side of the first electrode plate in the width direction X, a plurality of welds 222 are formed at intervals in the length direction Y of the first electrode plate. In the length direction Y of the first electrode plate, a body portion defined by the first weld 222a near the winding starting end 223 and the second weld 222b near the winding ending end 224 of the first electrode plate 221 is divided into a plurality of sub-segments 2251 of equal length, and the total length of the welds 222 in each sub-segment 2251 is 5% or more of the length of the sub-segment 2251. This makes the distribution of the welds 222 formed by welding the first electrode plate 221 to the current collecting member 24 more rational, reduces the internal resistance of the battery cell 20, meets actual overcurrent needs, and improves the power performance of the battery cell 20. The length of each sub-segment 2251 ranges from 200 mm to 1200 mm, so that the winding length of the first electrode plate 221 meets the needs of the actual product, and the battery cell 20 has a high energy density.

[0079] 5 and 6, in some embodiments, the absolute value of the difference in total length of the weld 222 of any two sub-segments 2251 is 10 mm or less.

[0080] 5 and 6, the length of each weld 222 in one of any two subsegments 2251 is defined as L1, ..., Ln, respectively, and the length of each weld 222 in the other of any two subsegments 2251 is defined as H1, ..., Hm, respectively, where n and m are both natural numbers greater than or equal to 1. The relationship satisfies -10 mm ≦ (L1 + ... + Ln) - (H1 + ... + Hm) ≦ 10 mm.

[0081] Controlling the absolute value of the difference in the total lengths of the welds 222 of any two subsegments 2251 to within 10 mm and minimizing the difference in the total lengths of the welds 222 of each subsegment 2251 as much as possible makes the distribution of the welds 222 more reasonable, helps reduce the internal resistance of the battery cell 20, and reduces the difference in the overcurrent capacity of each subsegment 2251, meeting actual overcurrent needs and improving the power performance of the battery cell 20. Controlling the absolute value of the difference in the total lengths of the welds 222 of any two subsegments 2251 to within 10 mm is equivalent to keeping the error in the weld width of each subsegment 2251 to within 10 mm, and since an error in the total weld length between each subsegment 2251 is allowed, the difficulty of welding can be reduced.

[0082] In some embodiments, the total length of the weld 222 of any two sub-segments 2251 is the same.

[0083] The total length of the welds 222 of any two sub-segments 2251 being the same may be understood to mean that the difference in total length of the welds 222 of any two sub-segments 2251 is zero.

[0084] If the total lengths of the welds 222 of any two sub-segments 2251 are the same, there will be no difference in the total lengths of the welds 222 of each sub-segment 2251, making the distribution of the welds 222 more reasonable, reducing the internal resistance of the battery cell 20 as much as possible, and making the overcurrent capacity of each sub-segment 2251 the same, meeting the actual overcurrent needs and improving the power performance of the battery cell 20.

[0085] In some embodiments, the absolute value of the difference between the number of welds 222 in any two sub-segments 2251 is 10 or less.

[0086] In FIG. 5, −10≦nm≦10, that is, the absolute value of the difference between the numbers of welds 222 of any two sub-segments 2251 is 10 or less.

[0087] Controlling the absolute value of the difference in the number of welds 222 between any two subsegments 2251 to within 10 reduces the number of welds in each subsegment 2251 as much as possible, reducing the internal resistance of the battery cell 20, minimizing the difference in the overcurrent capacity of each subsegment 2251, meeting actual overcurrent needs, and improving the power performance of the battery cell 20. Controlling the absolute value of the difference in the number of welds 222 between any two subsegments 2251 to within 10 is equivalent to allowing the number of welds 222 in each subsegment 2251 to differ, and allowing for some error in the total weld length between each subsegment 2251, thereby reducing the difficulty of welding.

[0088] In some embodiments, the number of welds 222 for any two sub-segments 2251 is the same.

[0089] The fact that the number of welds 222 in any two subsegments 2251 is the same may be understood as the difference in the number of welds 222 in any two subsegments 2251 being zero, and in Fig. 6, nm = 0. As shown in Fig. 4, the second region 226b, the third region 226c, the fourth region 226d, the fifth region 226e, and the sixth region 226f each have one subsegment 2251, and the number of welds 222 in the second region 226b, the third region 226c, the fourth region 226d, the fifth region 226e, and the sixth region 226f are the same.

[0090] If the number of welds 222 of any two sub-segments 2251 is the same, the difference in the total length of the welds 222 of each sub-segment 2251 should be reduced as much as possible, making the distribution of the welds 222 more reasonable, which is helpful in reducing the internal resistance of the battery cell 20, making the overcurrent capacity of each sub-segment 2251 the same, meeting the actual overcurrent needs, and improving the power performance of the battery cell 20.

[0091] Continuing with reference to Figures 4, 5 and 6, in some embodiments, the first plate 221 further includes a winding start segment 228 that is continuous with the main body segment 225, and the winding start segment 228 extends from the winding start end 223 to an edge of the first weld 222a that is close to the winding start end 223.

[0092] The fact that the main body segment 225 is provided contiguous with the winding start segment 228 means that the winding start segment 228 is directly connected to the main body segment 225. After winding is completed, the annular layer formed by winding the winding start segment 228 is located inside the annular layer formed by winding the main body segment 225. As shown in FIGS. 4, 5, and 6, the winding start segment 228 is located in the first region 226a, and no weld 222 is provided.

[0093] In some embodiments, the first plate 221 may include only the winding start segment 228 and the body segment 225. In other embodiments, the first plate 221 may include only the body segment 225.

[0094] The winding start segment 228 extends from the winding start end 223 to the edge of the first weld 222a that is closest to the winding start end 223; that is, the winding start segment 228 is defined by the winding start end 223 and the edge of the first weld 222a that is closest to the winding start end 223; in other words, the winding start end 223 extends beyond the first weld 222a; no weld 222 is formed in the winding start segment 228; there is no welded relationship between the winding start segment 228 and the current collecting member 24 (shown in FIG. 3 ); the portion of the current collecting member 24 (shown in FIG. 3 ) that corresponds to the tab of the winding start segment 228 is not welded and can be used for welding to the electrode terminal 232 to output electrical energy from the battery cell 20.

[0095] The length of the winding start segment 228 may be different for different battery cells 20. In some embodiments, the length of the winding start segment 228 is A, where A≦L.

[0096] The length of the winding start segment 228 refers to the distance between the winding start end 223 and the edge of the first welded portion 222a that is closest to the winding start end 223 when the first electrode plate 221 is in the unfolded state.

[0097] In the longitudinal direction Y of the first plate, the distance between the winding start end 223 and the first weld 222a is shorter than the length of the sub-segment, i.e., the length of the winding start segment 228 where the weld 222 is not provided is shorter than the length of the sub-segment 2251 where the weld 222 is provided, thereby preventing the length of the section of the first plate 221 where the weld 222 is not provided from being too long and ensuring stable output of electrical energy from the battery cell 20.

[0098] 7, 8, and 9, Fig. 7 is a structural schematic diagram of an electrode assembly 22 provided according to some other embodiments of the present application, Fig. 8 is an expanded view of a first electrode plate 221 provided according to some other embodiments of the present application, and Fig. 9 is a dimensional schematic diagram of the expanded state of the first electrode plate 221 provided according to some other embodiments of the present application. In some embodiments, the first electrode plate 221 further includes a winding end segment 229 provided continuously with the main body segment 225, and the winding end segment 229 extends from the winding end end 224 to an edge of the second welded portion 222b close to the winding end end 224.

[0099] The main body segment 225 being provided continuously with the winding end segment 229 means that the winding end segment 229 is directly connected to the main body segment 225. After winding is completed, the annular layer formed by winding the winding end segment 229 is located outside the annular layer formed by winding the main body segment 225. As shown in FIGS. 6 and 7 , the winding end segment 229 is located in the sixth region 226f, and no weld 222 is provided.

[0100] In some embodiments, the first electrode plate 221 may include only the winding end segment 229 and the main body segment 225. In other embodiments, as shown in Figures 10 and 11, the first electrode plate 221 may include the winding start segment 228, the main body segment 225, and the winding end segment 229, which are connected in sequence.

[0101] The winding end segment 229 extends from the winding end end 224 to the edge of the second welded portion 222b that is closest to the winding end end 224; that is, the winding end segment 229 is defined by the winding end end 224 and the edge of the second welded portion 222b that is closest to the winding end end 224; in other words, the winding end end 224 extends beyond the second welded portion 222b, no welded portion 222 is formed in the winding end segment 229, there is no welded relationship between the winding end segment 229 and the current collecting member 24 (shown in FIG. 3 ), and the portion of the current collecting member 24 (shown in FIG. 3 ) that corresponds to the tab portion of the winding end segment 229 is not welded and can be used for welding to the electrode terminal 232 to output electrical energy from the battery cell 20.

[0102] The length of the winding end segment 229 may be different for different battery cells 20, and the length of the winding end segment 229 needs to meet the actual needs of the electrode assembly 22. In some embodiments, the length of the winding end segment 229 is B, where B≦L.

[0103] When the first electrode plate 221 is in the deployed state, the length of the winding end segment 229 refers to the distance between the winding end 224 and the edge of the second welded portion 222b that is closest to the winding end 224.

[0104] In the longitudinal direction Y of the first plate, the length of the winding end segment 229 is shorter than the length of the sub-segment 2251, i.e., the length of the winding start segment 228 where the weld 222 is not provided is shorter than the sub-segment 2251 where the weld 222 is provided, thereby preventing the length of the section of the first plate 221 where the weld 222 is not provided from being too long and ensuring stable output of electrical energy from the battery cell 20.

[0105] 12 and 13, Fig. 12 is a schematic diagram of an electrode assembly 22 provided according to further some embodiments of the present application, and Fig. 13 is a structural schematic diagram of an electrode assembly 22 provided according to still further some embodiments of the present application. In some embodiments, of two adjacent turns of first electrode plates 221, the number of welds 222 in one turn closer to the winding center of the electrode assembly 22 is smaller than the number of welds 222 in one turn away from the winding center.

[0106] The phrase "among two adjacent sets of first electrode plates 221" described here may refer to any two adjacent sets of first electrode plates 221, or may refer to some of two adjacent sets of first electrode plates 221.

[0107] 12, each region has one turn of the first electrode plate 221, where in the first region 226a, two welds 222 are provided on each turn of the first electrode plate 221, in the second region 226b, four welds 222 are provided on each turn of the first electrode plate 221, in the third region 226c, six welds 222 are provided on each turn of the first electrode plate 221, in the fourth region 226d, six welds 222 are provided on each turn of the first electrode plate 221, and in the fifth region 226e, six welds 222 are provided on each turn of the first electrode plate 221. The welds 222 are distributed radially.

[0108] As shown in FIG. 13, each region has one turn of the first electrode plate 221, and in the second region 226b, four welds 222 are provided on the first electrode plate 221 of some of the annular layers, five welds 222 are provided on the first electrode plate 221 of some of the annular layers, and six welds 222 are provided on the first electrode plate 221 of other annular layers; in the third region 226c, six welds 222 are provided on the first electrode plate 221 of each turn; in the fourth region 226d, six welds 222 are provided on the first electrode plate 221 of each turn; in the fifth region 226e, six welds 222 are provided on the first electrode plate 221 of each turn; and in the sixth region 226f, six welds 222 are provided on the first electrode plate 221 of some of the annular layers, and five welds 222 are provided on the first electrode plate 221 of other annular layers. Some of the welds 222 are distributed radially, and some of the welds 222 are connected to form arc segments surrounding the winding center of the electrode assembly 22, and the arc segments are located in a sixth region 226f, and the arc segments connect two adjacent radial lines made up of the welds 222.

[0109] In other embodiments, the number of welds 222 on any two adjacent first plates 221 may be the same.

[0110] For the wound electrode assembly 22, the length of one turn of two adjacent first plates 221 closer to the winding center is shorter than the length of one turn away from the winding center. During welding, the number of welds 222 formed in one turn of the wound electrode assembly 22 closer to the winding center is smaller than the number of welds 222 in one turn away from the winding center. The length of each turn of the first plates 221 and the number of welds 222 corresponding to each turn of the first plates 221 are adapted to the total length of the welds 222. This makes the distribution of the welds 222 more reasonable, reduces the internal resistance of the battery cell 20, meets the actual overcurrent needs, and improves the power performance of the battery cell 20.

[0111] 3, 4, 5, and 6, in some embodiments, the battery cell 20 further includes a housing 21, an end cover assembly 23, and a current collecting member 24, wherein the housing 21 is used to house the electrode assembly 22 and has an opening 211, the end cover assembly 23 includes an end cover 231 for covering the opening 211 and an electrode terminal 232 attached to the end cover 231, the current collecting member 24 is located between the end cover 231 and the electrode assembly 22 and is used to connect a tab portion of the electrode assembly 22 to the electrode terminal 232, the tab portion being formed by winding an uncoated region of the first electrode plate 221, and at least a portion of the current collecting member 24 is welded to the tab portion to form a plurality of welds 222.

[0112] At least a portion of the current collecting member 24 is welded to the tab portion to form a plurality of welds 222. In the longitudinal direction Y of the first plate, a main body defined by a first weld 222a near the winding starting end 223 and a second weld 222b near the winding ending end 224 of the first plate 221 is divided into a plurality of sub-segments 2251 of equal length, and the total length of the welds 222 of each sub-segment 2251 is 5% or more of the length of the sub-segment 2251. This makes the distribution of the welds 222 formed by welding the first plate 221 and the current collecting member 24 more rational, reduces the internal resistance of the battery cell 20, meets actual overcurrent needs, and improves the power performance of the battery cell 20.

[0113] Please refer to FIG. 14, which is a schematic diagram of a current collecting member 24 after welding provided in accordance with some embodiments of the present application. In some embodiments, the first electrode plate 221 further includes a winding start segment 228 extending from the winding start end 223 to an edge of the first weld 222 a that is close to the winding start end 223; the uncoated region of the main body segment 225 is wound to form a first portion 12 (not shown); the uncoated region of the winding start segment 228 is wound to form a second portion 13 (not shown); the second portion 13 is located radially inside the first portion 12; the current collecting member 24 includes a first current collecting portion 241 and a second current collecting portion 242 that are arranged continuously in the radial direction; the first current collecting portion 241 faces the first portion 12 in the width direction X of the first electrode plate and is welded to the first portion 12 to form a plurality of welds 222; and the second current collecting portion 242 faces the second portion 13 in the width direction X of the first electrode plate and is welded to an electrode terminal 232.

[0114] When the first electrode plate 221 is in a wound state, the width direction X of the first electrode plate coincides with the winding axis direction of the electrode assembly 22. Because the uncoated area of ​​the first electrode plate 221 is used to form the tab of the first electrode plate 221, both the first portion 12 and the second portion 13 belong to the tab of the first electrode plate 221. The second portion 13 being located radially inward of the first portion 12 may mean that a part of the second portion 13 is located inside the first portion 12 and another part of the second portion 13 is located on the same circumference as a part of the first portion 12, or may mean that the entire second portion 13 is located inside the first portion 12 and the first portion 12 is provided to surround the outer periphery of the second portion 13.

[0115] The fact that the first current collecting portion 241 is arranged opposite the first portion 12 in the width direction X of the first electrode plate may be understood to mean that the projection of the first portion 12 onto the current collecting member 24 at least partially overlaps with the first current collecting portion 241 in the width direction X of the first electrode plate, and the overlapping portions are welded to each other to form a plurality of welds 222, thereby realizing electrical connection between the electrode assembly 22 and the current collecting member 24. The first current collecting portion 241 and the second current collecting portion 242 are arranged continuously in the radial direction, and the winding start segment 228 extends from the winding start end 223 to the edge of the first welded portion 222a that is closest to the winding start end 223. That is, the winding start segment 228 is defined by the winding start end 223 and the edge of the first welded portion 222a that is closest to the winding start end 223. No welded portion 222 is formed in the winding start segment 228. That is, there is no welding relationship between the second portion 13 formed by winding the uncoated area of ​​the winding start segment 228 and the current collecting member 24. No welding marks are formed on the second current collecting portion 242 that faces the second portion 13. This facilitates welding between the current collecting member 24 and the electrode terminal 232 via the second current collecting portion 242, thereby enabling the output of electrical energy from the battery cell 20.

[0116] Referring to FIG. 15, FIG. 15 is a schematic diagram of a current collecting member 24 after welding provided according to some other embodiments of the present application. In some embodiments, the first electrode plate 221 further includes a winding end segment 229 extending from the winding end end 224 to an edge of the second weld 222 b that is close to the winding end segment 229; the uncoated region of the main body segment 225 is wound to form the first portion 12; the uncoated region of the winding end segment 229 is wound to form a third portion (not shown); the third portion is located radially outward from the first portion 12; the current collecting member 24 includes a first current collecting portion 241 and a third current collecting portion 243 that are arranged continuously in the radial direction; the first current collecting portion 241 faces the first portion 12 and the first electrode plate in the width direction X and is welded to the first portion 12 to form a plurality of welds 222; and the third current collecting portion 243 faces the third portion and the first electrode plate in the width direction X and is welded to the electrode terminal 232.

[0117] Because the uncoated area of ​​the first electrode plate 221 is used to form the tab of the first electrode plate 221, both the first portion 12 and the third portion belong to the tab of the first electrode plate 221. The third portion being located radially outside the first portion 12 may mean that a part of the third portion is located outside the first portion 12 and another part of the third portion is located on the same circumference as a part of the first portion 12, or may mean that the entire third portion is located inside the first portion 12 and the third portion is provided around the outer periphery of the first portion 12.

[0118] 16 is a schematic diagram of a current collecting member 24 after welding according to yet another embodiment of the present application. In an embodiment in which a first electrode plate 221 includes a winding start segment 228, a main body segment 225, and a winding end segment 229, the current collecting member 24 may include a second current collecting portion 242, a first current collecting portion 241, and a third current collecting portion 243 arranged radially from the inside to the outside. The first current collecting portion 241 is welded to the first portion 12, the second current collecting portion 242 is disposed opposite the second portion 13 in the width direction X of the first electrode plate, and the third current collecting portion is disposed opposite the third portion in the width direction X of the first electrode plate. The second current collecting portion 242 and the third current collecting portion 243 are welded to electrode terminals 232 to output electrical energy from the battery cell 20.

[0119] The first current collecting portion 241 is welded to the first portion 12 to achieve electrical connection between the electrode assembly 22 and the current collecting member 24. The third current collecting portion 243 and the first current collecting portion 241 are arranged continuously in the radial direction. The winding end segment 229 is from the winding end end 224 to the edge of the second welded portion 222b that is close to the winding end end 224. That is, the winding end segment 229 is formed by the winding end end 224 and the edge of the second welded portion 222b that is close to the winding end end 224. The winding end segment 229 is defined such that no welded portion 222 is formed in the winding end segment 229, i.e., there is no welding relationship between the third portion formed by winding the non-coated area of ​​the winding end segment 229 and the current collecting member 24, and no welding marks are formed on the third current collecting portion 243 facing the third portion, which makes it easy to weld the current collecting member 24 and the electrode terminal 232 via the third current collecting portion 243, thereby enabling the output of electrical energy from the battery cell 20.

[0120] An embodiment of the present application provides a cylindrical battery including a cylindrical housing 21, a cylindrical electrode assembly 22, a current collecting member 24, and an end cover assembly 23, wherein the electrode assembly 22 is housed in a case, an end cover 231 of the end cover assembly 23 covers an opening 211 of the housing 21, the electrode assembly 22 includes a first electrode plate 221, the first electrode plate 221 includes a winding start end 223 and a winding end end 224, and the welded portion 222 closest to the winding start end 223 is a first welded portion 222a. The first electrode plate 221 includes a main body segment 225 extending from the edge of the first weld 222a closest to the winding start end 223 to the edge of the second weld 222b closest to the winding end 224, the main body segment 225 being equally divided into a plurality of subsegments 2251 each having a length L, the total length of the welds 222 in each subsegment 2251 being equal to or greater than 5%*L, and 200 mm≦L≦1200 mm. The absolute value of the difference in the total lengths of the welds 222 between any two subsegments 2251 is equal to or less than 10 mm, and the absolute value of the difference in the number of welds 222 between any two subsegments 2251 is equal to or less than 10. The first electrode plate 221 further includes a winding start segment 228 and a winding end segment 229 that are provided continuously with the main body segment 225, the winding start segment 228 extending from the winding start end 223 to the edge of the first welded portion 222a that is closest to the winding start end 223. The winding end segment 229 extends from the winding end end 224 to the edge of the second welded portion 222b that is closest to the winding end 224, the length of the winding start segment 228 being A and the length of the winding end segment 229 being B, where A≦L and B≦L are satisfied. The current collecting member 24 includes a second current collecting portion 242, a first current collecting portion 241, and a third current collecting portion 243 that are arranged continuously from the inside to the outside along the radial direction.The uncoated area of ​​the main body segment 225 is wound up to form the first portion 12, the uncoated area of ​​the winding start segment 228 is wound up to form the second portion 13, and the uncoated area of ​​the winding end segment 229 is wound up to form the third portion, and in the width direction X of the first plate, the first current collecting portion 241 is provided opposite to the first portion 12 and is welded to the first portion 12 to form a plurality of welds 222, the second current collecting portion 242 is provided opposite to the second portion 13 and is welded to the electrode terminal 232, and the third current collecting portion 243 is provided opposite to the third portion and is welded to the electrode terminal 232, thereby outputting electrical energy from the cylindrical battery.

[0121] The present embodiment further provides a battery 100 including a battery cell 20 provided by any of the above embodiments.

[0122] An embodiment of the present application further provides a power consuming device including the battery 100 provided by the above embodiment.

[0123] The above is only a preferred embodiment of the present application, and is not intended to limit the present application. Those skilled in the art can make various modifications and variations to the present application. All modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application. [Explanation of symbols]

[0124] 1000 vehicles 100 batteries 10. Cabinet 11 Storage space 12 First Part 13 Second Part 20 battery cells 21 Housing 211 Aperture 22 Electrode assembly 221 First Plate 2211 Coating Area 2212 Uncoated area 222 Welded parts 222a First Weld 222b Second weld 223 Winding start end 224 Winding end 225 body segments 2251 subsegments 226 Winding center hole 226a First Region 226b Second Realm 226c Third Realm 226d The Fourth Realm 226e The Fifth Realm 226f The Sixth Realm 227a First Ring 227b Second Ring 227c Third Ring 227d Fourth Ring 227e The Fifth Ring 228 Winding start segment 229 Winding end segment 23 End cover assembly 231 End cover 232 Electrode terminal 24 Current collecting member 241 First current collector 242 Second current collector 243 Third current collector 200 Controller 300 motor X: Width direction of the first electrode plate Y Lengthwise direction of the first electrode plate

Claims

1. an electrode assembly including a first electrode plate; a plurality of welds are provided on one side of the first electrode plate in a width direction, and the plurality of welds are provided at intervals in a length direction of the first electrode plate; the electrode assembly has a winding structure; the first electrode plate includes a winding start end and a winding end end, Among the plurality of welded portions, the one closest to the winding start end is a first welded portion, and among the plurality of welded portions, the one closest to the winding end end is a second welded portion, the first electrode plate includes a main body segment extending from an edge of the first welded portion close to the winding start end to an edge of the second welded portion close to the winding end end, the main body segment being equally divided into a plurality of sub-segments each having a length L; the total length of the welds in each of the sub-segments is equal to or greater than 5%*L, and 200 mm≦L≦1200 mm; a housing used to house the electrode assembly and having an opening; an end cover assembly including an end cover for covering the opening and an electrode terminal attached to the end cover; a current collecting member positioned between the end cover and the electrode assembly for connecting a tab portion of the electrode assembly to the electrode terminal; Further comprising: the tab portion is formed by winding an uncoated region of the first electrode plate, and at least a portion of the current collecting member is welded to the tab portion to form the plurality of welds; the first electrode plate further includes a winding start segment extending from the winding start end to an edge of the first welded portion that is close to the winding start end; an uncoated region of the body segment being wound to form a first portion; an uncoated region of the winding start segment is wound to form a second portion, the second portion being radially inward of the first portion; the current collecting member includes a first current collecting portion and a second current collecting portion that are arranged continuously in a radial direction, the first current collecting portion is provided opposite to the first portion in the width direction of the first electrode plate and is welded to the first portion to form the plurality of welds; the second current collecting portion is disposed opposite the second portion in the width direction of the first electrode plate and is welded to the electrode terminal, and the second portion is not welded to the second current collecting portion.

2. The battery cell according to claim 1 , wherein the absolute value of the difference in total length of the welded portions of any two of the sub-segments is 10 mm or less.

3. The battery cell according to claim 1 or 2, wherein the total length of the welded portions of any two of the sub-segments is the same.

4. The battery cell according to any one of claims 1 to 3, wherein the absolute value of the difference between the number of welds of any two of the sub-segments is 10 or less.

5. The battery cell according to any one of claims 1 to 4, wherein the number of welds in any two of the sub-segments is the same.

6. The first electrode plate further includes a winding start segment provided continuously with the main body segment, The battery cell according to any one of claims 1 to 5, wherein the winding start segment extends from the winding start end to an edge of the first welded portion that is close to the winding start end.

7. The battery cell according to claim 6 , wherein the length of the winding start segment is A, and A≦L is satisfied.

8. The first electrode plate further includes a winding end segment provided continuously with the main body segment, The battery cell according to any one of claims 1 to 7, wherein the winding end segment extends from the winding end to an edge of the second welded portion that is close to the winding end.

9. The battery cell according to claim 8 , wherein the length of the winding end segment is B, and B≦L is satisfied.

10. 10. The battery cell according to claim 1, wherein, in two adjacent turns of the first electrode plate, the number of welds in one turn closer to the winding center of the electrode assembly is smaller than the number of welds in one turn farther from the winding center.

11. the first electrode plate further includes a winding end segment extending from the winding end to an edge of the second welded portion that is close to the winding end, an uncoated region of the body segment being wound to form a first portion; an uncoated region of the winding end segment is wound to form a third portion, the third portion being radially outward of the first portion; the current collecting member includes a first current collecting portion and a third current collecting portion that are arranged continuously in a radial direction, the first current collecting portion is provided opposite to the first portion in the width direction of the first electrode plate and is welded to the first portion to form the plurality of welds; The battery cell according to claim 1 , wherein the third current collecting portion is provided opposite the third portion in the width direction of the first electrode plate and is welded to the electrode terminal.

12. A battery comprising the battery cell according to any one of claims 1 to 11.

13. 13. A power consuming device comprising the battery of claim 12.

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