Battery monomer, battery and electric device

Abstract

The utility model provides a battery monomer, a battery and a power utilization device. The battery monomer comprises an electrode assembly, a first electrode terminal, a second electrode terminal and a current collector; the electrode assembly comprises a main body part, and a first tab and a second tab are led out from the same side of the main body part; the current collecting piece comprises a first current collecting part made of a first material, a second current collecting part made of a second material and an insulating part connected with the first current collecting part and the second current collecting part, the first current collecting part is connected with the first electrode terminal and the first tab, and the second current collecting part is connected with the second electrode terminal and the second tab; the conductivity of the first material is larger than that of the second material, the size of the first current collecting part is smaller than that of the second current collecting part, and the range of the ratio of the internal resistance of the first current collecting part to the internal resistance of the second current collecting part is 95%-105%. The size of the first current collecting part is set to be smaller, so that the usage amount of the first material is reduced, the utilization rate of the first material is improved, the weight of the current collecting piece is reduced, and the energy density of the battery monomer is improved.

Description

Technical Field

[0001] This application belongs to the technical field of batteries, and more specifically, relates to a battery cell, a battery, and an electrical device. Background Art

[0002] Energy conservation and emission reduction are the keys to the sustainable development of the automotive industry. Electric vehicles have become an important part of the sustainable development of the automotive industry due to their advantages of energy conservation and environmental protection. For electric vehicles, battery technology is an important factor related to their development.

[0003] A battery cell generally includes an electrode assembly, a current collector, and electrode terminals. The current collector connects the tab of the electrode assembly to the electrode terminals so that current is conducted between the electrode terminals and the electrode assembly through the current collector. For a current collector that integrally connects the positive current collector and the negative current collector, the positive current collector and the negative current collector are usually symmetrically arranged. However, such an integrated current collector has a relatively large weight and a low material utilization rate. Summary of the Utility Model

[0004] The purpose of the embodiments of this application is to provide a battery cell, a battery, and an electrical device to improve the problems of relatively large weight and low material utilization rate of the integrated current collector in the related art.

[0005] In a first aspect, the embodiments of this application provide a battery cell, including:

[0006] An electrode assembly, including a main body portion, a first tab and a second tab are led out from the same side of the main body portion, and the polarities of the first tab and the second tab are opposite;

[0007] A first electrode terminal for electrically connecting the first tab;

[0008] A second electrode terminal for electrically connecting the second tab; and,

[0009] A current collector, including a first current collecting portion made of a first material, a second current collecting portion made of a second material, and an insulating portion connecting the first current collecting portion and the second current collecting portion. The first current collecting portion connects the first electrode terminal and the first tab, and the second current collecting portion connects the second electrode terminal and the second tab;

[0010] The conductivity of the first material is greater than that of the second material, the size of the first current collecting portion is smaller than that of the second current collecting portion, and the ratio of the internal resistance of the first current collecting portion to the internal resistance of the second current collecting portion ranges from 95% to 105%.

[0011] In the technical solution of the embodiment of the present application, by setting the size of the first current collector part to be small and making the ratio of the internal resistance of the first current collector part to the internal resistance of the second current collector part range from 95% to 105%, the overcurrent capabilities of the first current collector part and the second current collector part tend to be consistent. This can not only meet the overcurrent requirements for charging and discharging of the battery cell, but also reduce the usage amount of the first material, make better use of the first material, improve the utilization rate of the first material, and reduce the weight of the current collector, thereby improving the energy density of the battery cell.

[0012] In some embodiments, the first current collector part has a first area for connecting the first tab and a first connection area for connecting the first electrode terminal, and the second current collector part has a second area for connecting the second tab and a second connection area for connecting the second electrode terminal;

[0013] The overall size from the first area to the first connection area is smaller than the overall size from the second area to the second connection area, and the ratio of the internal resistance from the first area to the first connection area to the internal resistance from the second area to the second connection area ranges from 95% to 105%.

[0014] The first area is provided to facilitate the connection between the first current collector part and the first tab, and the first connection area is provided to facilitate the connection between the first current collector part and the first electrode terminal; the second area is provided to facilitate the connection between the second current collector part and the second tab, and the second connection area is provided to facilitate the connection between the second current collector part and the second electrode terminal; in addition, by making the overall size from the first area to the first connection area smaller than the overall size from the second area to the second connection area, such as reducing the area of the first area, and / or reducing the area of the first connection area, and / or reducing the thickness of the first current collector part, etc., the overall size from the first area to the first connection area is set to be small, so as to make the internal resistance from the first area to the first connection area tend to be consistent with the internal resistance from the second area to the second connection area, and further make the overcurrent capabilities from the first area to the first connection area and from the second area to the second connection area tend to be consistent, to meet the overcurrent requirements for charging and discharging of the battery cell, and the size of the part of the first current collector part outside the first area to the first connection area can be set to be small, so as to reduce the size of the first current collector part, and further reduce the overall size and weight of the current collector, and improve the energy density of the battery cell.

[0015] In some embodiments, along the thickness direction of the current collector, the overall projected area from the first area to the first connection area is smaller than the overall projected area from the second area to the second connection area.

[0016] Set the overall projected area from the first region to the first connection region to be smaller, so as to increase the internal resistance from the first region to the first connection region, and further make the internal resistance from the first region to the first connection region tend to be consistent with the internal resistance from the second region to the second connection region, thereby achieving the effect of making the overcurrent capacity from the first region to the first connection region tend to be consistent with the overcurrent capacity from the second region to the second connection region, so as to meet the overcurrent requirements for charging and discharging of the battery cell. Moreover, the size of the part of the first current collector outside the first region to the first connection region can be set to be smaller, so as to reduce the size of the first current collector, and further reduce the overall size and weight of the current collector part, and improve the energy density of the battery cell.

[0017] In some embodiments, the area of the first region is smaller than the area of the second region.

[0018] Set the area of the first region to be smaller than the area of the second region, which can increase the internal resistance from the first region to the first connection region, and further make the internal resistance from the first region to the first connection region tend to be consistent with the internal resistance from the second region to the second connection region.

[0019] In some embodiments, along the thickness direction of the current collector part, the projection of the first connection region coincides with at least part of the first region, and / or the projection of the second connection region coincides with at least part of the second region.

[0020] Making the projection of the first connection region coincide with at least part of the first region can make the path of the current from the first region to the first connection region shorter, can reduce the internal resistance from the first region to the first connection region, so as to improve the overcurrent capacity. Furthermore, when the overcurrent capacity from the first region to the first connection region meets the requirements, the overall size of the first region to the first connection region can be made smaller, and then the size of the first current collector can be made smaller, so as to reduce the material usage of the first current collector, improve the material utilization rate, and reduce the weight.

[0021] Making the projection of the second connection region coincide with at least part of the second region can make the path of the current from the second region to the second connection region shorter, can reduce the internal resistance from the second region to the second connection region, so as to improve the overcurrent capacity. Furthermore, when the overcurrent capacity from the second region to the second connection region meets the requirements, the overall size of the second region to the second connection region can be made smaller, and then the size of the second current collector can be made smaller, so as to reduce the material usage of the second current collector, improve the material utilization rate, and reduce the weight.

[0022] In some embodiments, along the thickness direction of the current collector part, the projection of the first connection region is spaced from the first region, the projection of the second connection region is spaced from the second region, and the distance between the projection of the first connection region and the first region is greater than or equal to the distance between the projection of the second connection region and the second region.

[0023] The projection of the first connection area is spaced apart from the first area to facilitate the positional distribution of the first connection area and the first area; the projection of the second connection area is spaced apart from the second area to facilitate the positional distribution of the second connection area and the second area; the distance between the projection of the first connection area and the first area is set to be relatively large, which can increase the overall internal resistance from the first area to the first connection area, so as to make the internal resistance from the first area to the first connection area tend to be consistent with the internal resistance from the second area to the second connection area.

[0024] In some embodiments, the thickness of the first current collector portion is less than the thickness of the second current collector portion.

[0025] The thickness of the first current collector portion is set to be relatively small so as to make the current-carrying capacity of the first current collector portion tend to be consistent with that of the second current collector portion, reduce the usage amount of the first material, make better use of the first material, improve the utilization rate of the first material, and reduce the weight of the current collector, thereby improving the energy density of the battery cell.

[0026] In some embodiments, in the direction from the first current collector portion to the second current collector portion, the thickness of the current collector gradually increases.

[0027] The thickness of the current collector is set to be gradually variable, which is convenient for design and also convenient to make the current-carrying capacity of the first current collector portion tend to be consistent with that of the second current collector portion, and to reduce the usage amount of the first material, make better use of the first material, improve the utilization rate of the first material, and reduce the weight of the current collector, thereby improving the energy density of the battery cell.

[0028] In some embodiments, the surface of the current collector facing away from the electrode assembly is planar, and the surface of the current collector facing the electrode assembly is stepped.

[0029] The surface of the current collector facing away from the electrode assembly is set to be planar to facilitate connection with the electrode terminal, and the surface of the current collector facing the electrode assembly is set to be stepped, which can facilitate the thickness of the first current collector portion to be set to be relatively small, so that the current-carrying capacity of the first current collector portion tends to be consistent with that of the second current collector portion, and to reduce the usage amount of the first material, make better use of the first material, improve the utilization rate of the first material, and reduce the weight of the current collector, thereby improving the energy density of the battery cell.

[0030] In some embodiments, the thickness of the insulating portion is greater than or equal to the thickness of the first current collector portion and less than or equal to the thickness of the second current collector portion.

[0031] The setting of the thickness of the insulating portion can better insulate and separate the first current collector portion and the second current collector portion, and is also convenient for the design and manufacture of the insulating portion.

[0032] In some embodiments, along the thickness direction of the current collector, the projected area of the first current collecting portion is smaller than the projected area of the second current collecting portion.

[0033] Setting the projected area of the first current collecting portion smaller along the thickness direction can make the size of the first current collecting portion smaller, so that the current-carrying capacity of the first current collecting portion is made to tend to be consistent with the current-carrying capacity of the second current collecting portion, and, reduce the usage amount of the first material, make better use of the first material, improve the utilization rate of the first material, and reduce the weight of the current collector, thereby improving the energy density of the battery cell.

[0034] In some embodiments, the first material is copper and the second material is aluminum.

[0035] Using copper for the first material, that is, the first current collecting portion is made of copper, and using aluminum for the second material, that is, the second current collecting portion is made of aluminum, is convenient for design and processing.

[0036] In some embodiments, the shape of the current collector is adapted to the shape of the end of the main body portion where the first tab is led out.

[0037] The above structural setting facilitates the connection and use of the current collector with the tab of the electrode assembly and is convenient for assembly.

[0038] In some embodiments, the battery cell is square and the current collector is rectangular sheet-shaped, or, the battery cell is cylindrical and the current collector is disc-shaped.

[0039] When the battery cell is square, setting the current collector as a rectangular sheet can better be applied to the battery cell, so as to increase the contact area between the current collector and the tab of the electrode assembly, facilitate connection, and can also reduce the internal resistance of the battery cell and improve the charge and discharge performance of the battery cell.

[0040] When the battery cell is cylindrical, setting the current collector as a disc can better be applied to the battery cell, so as to increase the contact area between the current collector and the tab of the electrode assembly, facilitate connection, and can also reduce the internal resistance of the battery cell and improve the charge and discharge performance of the battery cell.

[0041] In a second aspect, an embodiment of the present application provides a battery, including the battery cell as described in the above embodiment.

[0042] In a third aspect, an embodiment of the present application provides an electrical device, including the battery as described in the above embodiment.

[0043] The above description is only an overview of the technical solution of the present application. In order to be able to understand the technical means of the present application more clearly, it can be implemented according to the content of the description. And in order to make the above and other objects, features and advantages of the present application more obvious and understandable, the specific embodiments of the present application are specifically given below. Description of the Drawings

[0044] To more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings required for use in the embodiments or exemplary technical descriptions. Obviously, the drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0045] Figure 1 Structural schematic diagram of a vehicle according to some embodiments of the present application;

[0046] Figure 2 Exploded structural schematic diagram of a battery according to some embodiments of the present application;

[0047] Figure 3 Exploded structural schematic diagram of a battery cell according to some embodiments of the present application;

[0048] Figure 4 Front view structural schematic diagram of a current collector according to some embodiments of the present application;

[0049] Figure 5 Front view structural schematic diagram of a current collector according to some other embodiments of the present application;

[0050] Figure 6 Front view structural schematic diagram of a current collector according to some other embodiments of the present application;

[0051] Figure 7 Top view structural schematic diagram of a current collector according to some embodiments of the present application;

[0052] Figure 8 Top view structural schematic diagram of a current collector according to some other embodiments of the present application;

[0053] Figure 9 Top view structural schematic diagram of a current collector according to some other embodiments of the present application;

[0054] Figure 10 Top view structural schematic diagram of a current collector according to some other embodiments of the present application;

[0055] Figure 11 Exploded structural schematic diagram of an electrode assembly and a current collector according to some embodiments of the present application;

[0056] Figure 12 Top view structural schematic diagram of a current collector according to some embodiments of the present application.

[0057] Among them, the main reference signs in the drawings are as follows:

[0058] 1000 - vehicle; 1001 - battery; 1002 - controller; 1003 - motor;

[0059] 100 - Box body; 101 - First part; 102 - Second part;

[0060] 200 - Battery cell; 21 - Outer shell; 211 - Housing; 212 - End cap; 22 - Electrode assembly; 221 - Main body part; 222 - Tab; 2221 - First tab; 2222 - Second tab; 23 - Electrode terminal; 231 - First electrode terminal; 232 - Second electrode terminal; 24 - Current collector; 241 - First current collecting part; 2411 - First area; 2412 - First connection area; 242 - Second current collecting part; 2421 - Second area; 2422 - Second connection area; 243 - Insulating part. Detailed implementation mode

[0061] In order to make the technical problems, technical solutions and beneficial effects to be solved by this application clearer and more understandable, the following further details this application in combination with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain this application and are not used to limit this application.

[0062] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" and any variations thereof in the specification and claims of this application and the above accompanying drawings are intended to cover non - exclusive inclusion.

[0063] In the description of the embodiments of this application, technical terms such as "first" and "second" are only used to distinguish different objects and cannot be understood as indicating or implying relative importance or implicitly indicating the quantity, specific order or primary - secondary relationship of the indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more of such features.

[0064] Referring to "embodiment" herein means that a specific feature, structure or characteristic described in connection with the embodiment may be included in at least one embodiment of this application. The phrase appears in various places in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment mutually exclusive with other embodiments. Those skilled in the art explicitly and implicitly understand that the embodiments described herein can be combined with other embodiments in any suitable manner.

[0065] In the description of the embodiments of the present application, the term "and / or" is merely a description of the associated relationship of the associated objects, indicating that there can be three relationships. For example, A and / or B can represent three situations: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship.

[0066] In the description of the embodiments of the present application, the term "plurality" refers to two or more (including two). Similarly, "multiple groups" refers to two or more groups (including two groups), and "multiple pieces" refers to two or more pieces (including two pieces). The meaning of "several" is one or more, unless otherwise specifically defined.

[0067] In the description of the embodiments of the present application, for technical terms such as "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., the orientation or positional relationship indicated is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the embodiments of the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation on the embodiments of the present application.

[0068] In the description of the embodiments of the present application, unless otherwise clearly specified and limited, technical terms such as "installation", "connection", "connection", "fixation", etc. should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or integrated; it can also be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments of the present application can be understood according to specific situations.

[0069] In the description of the embodiments of the present application, unless otherwise clearly specified and limited, when an element is referred to as "fixed to" or "disposed on" another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element.

[0070] In the description of the embodiments of the present application, unless otherwise clearly specified and limited, the technical term "proximity" refers to being close in position. For example, for three components A1, A2, and B, if the distance between A1 and B is greater than the distance between A2 and B, then A2 is closer to B than A1, that is, A2 is in proximity to B, or it can also be said that B is in proximity to A2. Another example is when there are multiple C components, which are C1, C2... C N , when one of the C components, such as C2, is closer to the B component than other C components, then B is in proximity to C2, or it can also be said that C2 is in proximity to B.

[0071] The battery cells in the embodiments of the present application include, but are not limited to, lithium-ion secondary battery cells, lithium-ion primary battery cells, lithium-sulfur battery cells, sodium-lithium-ion battery cells, sodium-ion battery cells, magnesium-ion battery cells, etc. The shape of the battery cell includes, but is not limited to, being cylindrical, flat, cuboid, or other shapes. The battery cells are generally classified by the encapsulation method, including, but not limited to: cylindrical battery cells, square battery cells, and soft-pack battery cells.

[0072] The battery mentioned in the embodiments of the present application refers to a single physical module including one or more battery cells to provide higher voltage and capacity. For example, the battery mentioned in the present application may include a battery module, a battery pack, or a battery case, etc. The battery generally includes a box for encapsulating one or more battery cells. The box can, to a certain extent, prevent liquids or other foreign objects from affecting the charging or discharging of the battery cells. In some cases, the battery cells can also be used directly, that is, the battery may not include a box, which is not limited herein.

[0073] In a battery, when there are multiple battery cells, the multiple battery cells can be connected in series, in parallel, or in a series-parallel combination. A series-parallel combination means that there are both series and parallel connections among the multiple battery cells. The multiple battery cells can be directly connected in series, in parallel, or in a series-parallel combination together, and then the whole formed by the multiple battery cells is accommodated in the box; of course, the battery can also be that multiple battery cells are first connected in series, in parallel, or in a series-parallel combination to form a battery module, and then multiple battery modules are connected in series, in parallel, or in a series-parallel combination to form a whole and are accommodated in the box. The battery can also include other structures. For example, the battery can also include a busbar component for realizing the electrical connection among the multiple battery cells.

[0074] The battery cell in the embodiments of the present application includes an electrode assembly and a housing, and the electrode assembly is installed in the housing to protect the electrode assembly through the housing.

[0075] The electrode assembly, also known as the bare battery cell, is a component that stores and releases electrical energy. The electrode assembly consists of a positive electrode sheet, a negative electrode sheet, and a separator. The electrode assembly mainly operates by the movement of metal ions between the positive electrode sheet and the negative electrode sheet. The positive electrode sheet 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 part of the positive electrode current collector that is not coated with the positive electrode active material layer protrudes from the part that is coated with the positive electrode active material layer. The part that is not coated with the positive electrode active material layer serves as the positive electrode tab, or a metal conductor is welded and led out on the positive electrode current collector to serve as the positive electrode tab. Taking a lithium-ion battery as an example, the material of the positive electrode current collector can be aluminum, and the positive electrode active material can be lithium cobaltate, lithium iron phosphate, ternary lithium, lithium manganate, etc. The negative electrode sheet 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 part of the negative electrode current collector that is not coated with the negative electrode active material layer protrudes from the part that is coated with the negative electrode active material layer. The part that is not coated with the negative electrode active material layer serves as the negative electrode tab, or a metal conductor is welded and led out on the negative electrode current collector to serve as the negative electrode tab. The material of the negative electrode current collector can be copper, and the negative electrode active material can be carbon or silicon, etc. In order to ensure to a certain extent that a large current can pass through without fusing, the number of positive electrode tabs is multiple and stacked together, and the number of negative electrode tabs is multiple and stacked together. It can be understood that in the electrode assembly, the number of positive electrode tabs can be one, and the number of negative electrode tabs can also be one. That is to say, there are two sets of tabs provided on the electrode assembly, each set includes at least one tab, and one set of tabs is the positive electrode tab, and the other set of tabs is the negative electrode tab. The positive electrode tab and the negative electrode tab are collectively referred to as tabs.

[0076] Electrode terminals will be provided on the outer shell of the battery cell. The electrode terminal refers to the conductive part provided on the outer shell. The electrode terminal is connected to the tab of the electrode assembly to output the electrical energy of the battery cell or to charge the battery cell. Generally, there are two electrode terminals for the battery cell. The two electrode terminals are respectively connected to the positive and negative electrode tabs of the electrode assembly. The electrode terminal connected to the positive electrode tab is the positive electrode terminal, and the electrode terminal connected to the negative electrode tab is the negative electrode terminal. The electrode assembly is connected to the electrode terminals to form a battery cell.

[0077] A current collector will also be provided in the battery cell. The current collector is a conductive part that can conduct current. The current collector connects the tab to the corresponding electrode terminal, so that the tab is connected to the corresponding electrode terminal through the current collector, which facilitates the connection between the tab and the electrode terminal and makes the connection more stable. When the battery cell is charged and discharged, the current flows between the tab and the corresponding electrode terminal through the current collector.

[0078] The current collectors are usually provided in two, corresponding to two electrode terminals respectively. However, this structure requires the two current collectors to be assembled separately, which results in a low assembly efficiency for the structure with the tab leads on the same side of the electrode assembly. Based on this, the two current collectors are often connected into one body and separated by an insulating part to form an integrated structure, so as to facilitate assembly and improve the assembly efficiency. Currently, the two conductive parts of this integrated current collector, that is, the two current collecting parts, are designed with the same size and are correspondingly arranged on opposite sides of the insulating part. However, since the two current collecting parts need to be welded to the corresponding tabs, the materials used are different, and accordingly, the conductivity is also different. In order to meet the over-current demand during the charge and discharge of the battery cell, the over-current capacity of the current collecting part made of the material with lower conductivity becomes the limitation of the overall current conduction capacity of the current collector, and also makes the size design of the current collecting part made of the material with higher conductivity need to accommodate the size of the current collecting part made of the material with lower conductivity, resulting in a relatively large overall weight of the current collector, low utilization rate of materials, and low weight energy density of the battery cell.

[0079] Based on the above considerations, in order to improve the problems of relatively large weight and low material utilization rate of the integrated current collector formed by integrating two current collecting parts in the battery cell, the embodiment of the present application provides a battery cell. By setting the size of the first current collecting part made of the first material with higher conductivity to be smaller than the size of the second current collecting part made of the second material with lower conductivity, and making the ratio of the internal resistance of the first current collecting part to the internal resistance of the second current collecting part range from 95% to 105%, the over-current capacities of the first current collecting part and the second current collecting part tend to be the same. In this way, not only can the over-current demand during the charge and discharge of the battery cell be met, but also the usage amount of the first material can be reduced, the first material can be better utilized, the utilization rate of the first material can be improved, and the weight of the current collector can be reduced, thereby improving the energy density of the battery cell.

[0080] The battery cell disclosed in the embodiment of the present application can be used in an electrical device using the battery as a power source or various energy storage systems using the battery as an energy storage element, such as energy storage power systems applied to hydroelectric, thermal, wind, and solar power stations, etc. The electrical device can be, but is not limited to, mobile phones, tablets, laptop computers, electric toys, power tools, electric bicycles, electric motorcycles, electric vehicles, ships, spacecraft, and the like. Among them, the electric toy can include fixed or mobile electric toys, for example, game consoles, electric vehicle toys, electric ship toys, and electric aircraft toys, etc., and the spacecraft can include airplanes, rockets, space shuttles, and spaceships, etc.

[0081] For the convenience of description, an embodiment of the present application provides an electrical device, and this electrical device is described by taking a vehicle as an example.

[0082] Please refer to Figure 1 , Figure 1Schematic structural diagram of vehicle 1000 provided by some embodiments of the present application. Vehicle 1000 can be a fuel vehicle, a gas vehicle, or a new energy vehicle. The new energy vehicle can be a pure electric vehicle, a hybrid vehicle, an extended-range vehicle, etc. A battery 1001 is disposed inside vehicle 1000, and the battery 1001 can be disposed at the bottom, head, or tail of vehicle 1000. The battery 1001 can be used to supply power to vehicle 1000. For example, the battery 1001 can be used as the operating power source of vehicle 1000. Vehicle 1000 can also include a controller 1002 and a motor 1003. The controller 1002 is used to control the battery 1001 to supply power to the motor 1003. For example, it is used for the working power requirements during the start, navigation, and driving of vehicle 1000.

[0083] In some embodiments of the present application, the battery 1001 can not only be used as the operating power source of vehicle 1000, but also as the driving power source of vehicle 1000, replacing or partially replacing fuel or natural gas to provide driving power for vehicle 1000.

[0084] In some embodiments of the present application, the battery 1001 involved in the embodiments of the present application can be used in an energy storage system that uses the battery as an energy storage element. Among them, the energy storage system can include an energy storage container, an energy storage cabinet, etc.

[0085] Please refer to Figure 2 , Figure 2 Schematic exploded view of the battery 1001 provided by some embodiments of the present application. The battery 1001 includes a box body 100 and battery cells 200, and the battery cells 200 are accommodated in the box body 100. Among them, the box body 100 is used to provide an accommodation space for the battery cells 200, and the box body 100 can adopt various structures. In some embodiments, the box body 100 can include a first part 101 and a second part 102. The first part 101 and the second part 102 cover each other, and the first part 101 and the second part 102 jointly define an accommodation space for accommodating the battery cells 200. The second part 102 can be a hollow structure with one end open, and the first part 101 can be a plate-like structure. The first part 101 covers the open side of the second part 102 so that the first part 101 and the second part 102 jointly define the accommodation space; the first part 101 and the second part 102 can also both be hollow structures with one side open, and the open side of the first part 101 covers the open side of the second part 102. Of course, the box body 100 formed by the first part 101 and the second part 102 can be of various shapes, such as a cylinder, a cuboid, etc. After a plurality of battery cells are connected in parallel, in series, or in a mixed connection combination, they are placed in the box body 100 formed by buckling the first part 101 and the second part 102.

[0086] Please refer to Figures 3 to 10, in some embodiments of the present application, the present application provides a battery cell 200 including an electrode assembly 22, a first electrode terminal 231, a second electrode terminal 232, and a current collector 24. The electrode assembly 22 includes a main body portion 221. A first tab 2221 and a second tab 2222 are led out from the same side of the main body portion 221, and the polarities of the first tab 2221 and the second tab 2222 are opposite; the first electrode terminal 231 is used to electrically connect to the first tab 2221; the second electrode terminal 232 is used to electrically connect to the second tab 2222; the current collector 24 includes a first current collecting portion 241 made of a first material, a second current collecting portion 242 made of a second material, and an insulating portion 243 connecting the first current collecting portion 241 and the second current collecting portion 242. The first current collecting portion 241 connects the first electrode terminal 231 and the first tab 2221, and the second current collecting portion 242 connects the second electrode terminal 232 and the second tab 2222; the conductivity of the first material is greater than that of the second material, the size of the first current collecting portion 241 is smaller than that of the second current collecting portion 242, and the ratio of the internal resistance of the first current collecting portion 241 to the internal resistance of the second current collecting portion 242 ranges from 95% to 105%.

[0087] The electrode assembly 22 is a component in the battery cell 200 that stores and releases electrical energy. The main body portion 221 is the main part of the electrode assembly 22. The tab 222 is a conductive component led out from the main body portion 221. The first tab 2221 and the second tab 2222 refer to the tabs 222 with opposite polarities led out from the main body portion 221. For example, if the first tab 2221 is a positive tab 222, then the second tab 2222 is a negative tab 222; if the first tab 2221 is a negative tab 222, then the second tab 2222 is a positive tab 222.

[0088] The fact that the first tab 2221 and the second tab 2222 are led out from the same side of the main body portion 221 means that the first tab 2221 and the second tab 2222 are located on the same side surface of the main body portion 221.

[0089] The first electrode terminal 231 refers to the electrode terminal 23 in the battery cell 200 used to electrically connect to the first tab 2221.

[0090] The second electrode terminal 232 refers to the electrode terminal 23 in the battery cell 200 used to electrically connect to the second tab 2222.

[0091] The current collector 24 refers to the conductive structure in the battery cell 200 for connecting the tab 222 and the electrode terminal 23. The current collector 24 is of a flat structure as a whole, such as a sheet structure, so as to connect the tab 222 and the electrode terminal 23. The shape of the current collector 24 can be circular, strip-shaped, polygonal, etc., which can be specifically set according to needs. The first current collection part 241 refers to the conductive part in the current collector 24 for connecting the first tab 2221 and the first electrode terminal 231 to achieve the electrical connection between the first tab 2221 and the first electrode terminal 231. The first current collection part 241 can be set in shapes such as a block, a plate, a strip, etc. The second current collection part 242 refers to the conductive part in the current collector 24 for connecting the second tab 2222 and the second electrode terminal 232 to achieve the electrical connection between the second tab 2222 and the second electrode terminal 232. The second current collection part 242 can be set in shapes such as a block, a plate, a strip, etc. The insulating part 243 refers to the structural member provided between the first current collection part 241 and the second current collection part 242 and connecting the first current collection part 241 and the second current collection part 242 to fixedly connect and insulatively separate the first current collection part 241 and the second current collection part 242. The insulating part 243 can be made of insulating materials such as plastic, bakelite, ceramic, etc. Connecting the first current collection part 241 and the second current collection part 242 into an integral body through the insulating part 243, during application and assembly, only by supplying the current collector 24, the supply of the first current collection part 241 and the second current collection part 242 can be realized, reducing the number of components and the number of times of taking and placing components, so as to reduce the processes and improve the assembly efficiency.

[0092] The connection of the first current collection part 241 to the first electrode terminal 231 and the first tab 2221 means two positions on the first current collection part 241, such as the two ends or two surfaces of the first current collection part 241 are respectively connected to the first electrode terminal 231 and the first tab 2221. The first current collection part 241 can be connected to the first tab 2221 in various ways. For example, the first current collection part 241 can be connected to the first tab 2221 by welding. Of course, the first current collection part 241 can also be connected to the first tab 2221 by bonding with a conductive adhesive. The first current collection part 241 can be connected to the first electrode terminal 231 in various ways. For example, the first current collection part 241 can be connected to the first electrode terminal 231 by welding; another example is that the first current collection part 241 can also be connected to the first electrode terminal 231 by bonding with a conductive adhesive; still another example is that the first current collection part 241 can also be riveted to the first electrode terminal 231.

[0093] The first material refers to the conductive material used to make the first current collector 241. Since the first current collector 241 needs to be connected to the first tab 2221, materials that are convenient for welding with the first tab 2221 are mostly used for the first material. For example, the first material can use the same material as the first tab 2221. If the first tab 2221 is made of copper, the first material can also be copper. Of course, if the first tab 2221 is made of aluminum, the first material can also use aluminum. Of course, the first material can also be made of other conductive materials, such as the first material can be nickel, gold, silver and other materials.

[0094] The second current collector 242 connecting the second electrode terminal 232 and the second tab 2222 refers to two positions on the second current collector 242, such as both ends or both sides of the second current collector 242 are respectively connected to the second electrode terminal 232 and the second tab 2222. The second current collector 242 can be connected to the second tab 2222 in a variety of ways. For example, the second current collector 242 can be welded to the second tab 2222. Of course, the second current collector 242 can also be adhesively connected to the second tab 2222 through conductive adhesive. The second current collector 242 can be connected to the second electrode terminal 232 in a variety of ways. For example, the second current collector 242 can be welded to the second electrode terminal 232; another example is that the second current collector 242 can also be adhesively connected to the second electrode terminal 232 through conductive adhesive; another example is that the second current collector 242 can also be riveted to the second electrode terminal 232.

[0095] The second material refers to the conductive material used to make the second current collector 242. Since the second current collector 242 needs to be connected to the second tab 2222, materials that are convenient for welding with the second tab 2222 are mostly used for the second material. For example, the second material can use the same material as the second tab 2222. If the second tab 2222 is made of copper, the second material can also be copper. Of course, if the second tab 2222 is made of aluminum, the second material can also use aluminum. Of course, the second material can also be made of other conductive materials, such as the second material can be nickel, gold, silver and other materials.

[0096] The overcurrent capacity refers to the ability of a conductive component to withstand without damage when the current exceeds the normal operating current. When the current exceeds the maximum value that the conductive component can withstand, it may cause faults such as overload, short circuit or burnout, thus affecting the function and life of the conductive component. The overcurrent capacity of a conductive component is related to its cross-sectional area, material, length and heat dissipation conditions.

[0097] Conductivity, also known as electrical conductivity, is a physical quantity that measures the conductivity of a material and is the reciprocal of resistivity. The unit of conductivity is Siemens per meter (S / m). The higher the conductivity, the better the electrical conductivity of the material.

[0098] If the conductivity of the first material is greater than that of the second material, then when the first current collector 241 and the second current collector 242 have the same size, the resistance of the first current collector 241 is less than that of the second current collector 242. Correspondingly, the current-carrying capacity of the first current collector 241 is also greater than that of the second current collector 242.

[0099] The size of the first current collector 241 refers to the external dimensions of the first current collector 241. The size of the second current collector 242 refers to the external dimensions of the second current collector 242. The current-carrying capacity of the first current collector 241 and that of the second current collector 242 tend to be the same, which can also be said that the current-carrying capacity of the first current collector 241 and that of the second current collector 242 are approximately equal. It means that the difference between the current-carrying capacity of the first current collector 241 and that of the second current collector 242 is within 5%. That is, the difference between the maximum current I1 that the first current collector 241 can withstand and the maximum current I2 that the second current collector 242 can withstand is within 5%. For example, the maximum current I1 that the first current collector 241 can withstand is 5% or less greater than the maximum current I2 that the second current collector 242 can withstand, that is: (I1 - I2) / I2 ≤ 5%; or, the maximum current I1 that the first current collector 241 can withstand is 5% or less less than the maximum current I2 that the second current collector 242 can withstand, that is: (I2 - I1) / I1 ≤ 5%; or, the maximum current I1 that the first current collector 241 can withstand is equal to the maximum current I2 that the second current collector 242 can withstand. Therefore, the range of the ratio of the internal resistance of the first current collector 241 to the internal resistance of the second current collector 242 is 95% - 105%, that is, the ratio of the internal resistance of the first current collector 241 to the internal resistance of the second current collector 242 is 95%, 96%, 97%, 98%, 99%, 100%, 101%, 102%, 103%, 104%, 105%, etc. That is, it can be considered that the internal resistance of the first current collector 241 and the internal resistance of the second current collector 242 tend to be the same, or it is considered that the internal resistance of the first current collector 241 and the internal resistance of the second current collector 242 are approximately equal. Correspondingly, it can also be considered that the current-carrying capacity of the first current collector 241 and the current-carrying capacity of the second current collector 242 tend to be the same or approximately equal.

[0100] Since the current-carrying capacity of the current collector 24 as a whole is determined by the one with the smaller current-carrying capacity among the first current collector 241 and the second current collector 242, therefore, if the current-carrying capacity of the one with the smaller current-carrying capacity among the first current collector 241 and the second current collector 242 can meet the current-carrying capacity requirement of the battery cell 200, then the current-carrying capacity of the current collector 24 as a whole can meet the current-carrying capacity requirement of the battery cell 200. Making the current-carrying capacity of the first current collector 241 and the current-carrying capacity of the second current collector 242 tend to be the same can meet the current-carrying requirement of the battery cell 200.

[0101] Since the conductivity of the first material is relatively high, the current-carrying capacity of the first current collector 241 can be reduced by setting the size of the first current collector 241 smaller than that of the second current collector 242, such as reducing the thickness of the first current collector 241 or reducing the area of the first current collector 241, so that the current-carrying capacity of the first current collector 241 is made to approach that of the second current collector 242. In this way, when meeting the over-current requirement of the battery cell 200, the size of the first current collector 241 can be designed to be smaller, and correspondingly, the amount of the first material used is also less, improving the utilization rate of the first material, reducing the weight of the first current collector 241, and further reducing the weight of the current collector 24, thereby improving the energy density of the battery cell 200, such as the weight density. In addition, due to the reduction in the size of the first current collector 241, there will be more space in the battery cell 200 to install other structural components of the battery cell 200, such as a pressure relief mechanism, a plastic structure, etc. The area of the first current collector 241 refers to the projected area of the first current collector 241 in the thickness direction.

[0102] In the technical solution of the embodiment of the present application, by setting the size of the first current collector 241 to be smaller and making the ratio of the internal resistance of the first current collector 241 to the internal resistance of the second current collector 242 range from 95% to 105%, the current-carrying capacity of the first current collector 241 is made to approach that of the second current collector 242. This can not only meet the over-current requirement for charging and discharging of the battery cell 200, but also reduce the amount of the first material used, make better use of the first material, improve the utilization rate of the first material, and reduce the weight of the current collector 24, thereby improving the energy density of the battery cell 200.

[0103] As Figure 3 shown, the battery cell 200 has a height direction, a length direction, and a width direction. In the figure, the Z direction is the height direction of the battery cell 200, the X direction is the length direction of the battery cell 200, and the Y direction is the width direction of the battery cell 200. The height direction of the electrode assembly 22 is the same as the height direction Z of the battery cell 200, the length direction of the electrode assembly 22 is the same as the length direction X of the battery cell 200, and the width direction of the electrode assembly 22 is the same as the width direction Y of the battery cell 200. Please refer to Figure 3 and Figure 4, the current collector 24 has a thickness direction H. When an end of the electrode assembly 22 in the height direction, such as the top end or the bottom end of the electrode assembly 22, leads out the tab 222, the thickness direction H of the current collector 24 is consistent with the height direction Z of the battery cell 200. For another example, when an end of the electrode assembly 22 in the length direction leads out the tab 222, the thickness direction H of the current collector 24 is consistent with the length direction X of the battery cell 200. The thickness direction of the first current collecting portion 241 is consistent with the thickness direction H of the current collector 24, the thickness direction of the second current collecting portion 242 is consistent with the thickness direction H of the current collector 24, and the thickness direction of the insulating portion 243 is consistent with the thickness direction H of the current collector 24.

[0104] In some embodiments, please refer to Figure 3 , the battery cell 200 includes a housing 21, the housing 21 includes a casing 211 and an end cap 212, the electrode assembly 22 is installed in the casing 211, and the end cap 212 covers the casing 211. The housing 21 is provided to protect the electrode assembly 22.

[0105] The end cap 212 refers to a component that covers the opening of the casing 211 to isolate the internal environment of the battery cell 200 from the external environment. The shape of the end cap 212 can be adapted to the shape of the casing 211 to cooperate with covering the casing 211. Optionally, the end cap 212 can be made of a material with a certain hardness and strength (such as aluminum alloy). In this way, the end cap 212 is not easily deformed when being squeezed or collided, so that the battery cell 200 can have a higher structural strength and the reliability performance can also be improved. The material of the end cap 212 can also be various, for example, copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc.

[0106] The casing 211 is a component used to cooperate with the end cap 212 to form the internal environment of the battery cell 200. Among them, the formed internal environment can be used to accommodate the electrode assembly 22, the electrolyte, and other components. The casing 211 and the end cap 212 can be independent components. An opening can be provided on the casing 211, and the end cap 212 is covered at the opening to form the internal environment of the battery cell 200. The casing 211 can be of various shapes and various sizes, such as a cuboid shape, a cylindrical shape, a hexagonal prism shape, etc. Specifically, the shape of the casing 211 can be determined according to the specific shape and size of the battery cell 200. The material of the casing 211 can be various, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc., and the embodiments of the present application do not make special restrictions on this.

[0107] In the embodiments of the present application, being approximately equal can be considered as tending to be consistent, which means that two-phase parameters or factors are equal or the difference is within 5%. That is, if two parameters or factors are equal or the difference is within 5%, then these two parameters or factors can be called approximately equal or tending to be consistent.

[0108] In some embodiments, referring to Figure 3 , the electrode terminal 23 may be disposed on the end cap 212 to support the electrode terminal 23 through the end cap 212. Of course, the electrode terminal 23 may also be disposed on the housing 211 to support the electrode terminal 23 through the housing 211.

[0109] In some embodiments, referring to Figure 3 , the battery cell 200 may include one or more electrode assemblies 22. When the battery cell 200 includes a plurality of electrode assemblies 22, the first tab 2221 of each electrode assembly 22 is connected to the first current collector 241, and the second tab 2222 of each electrode assembly 22 is connected to the second current collector 242. The term "plurality" means two or more.

[0110] In some embodiments, referring to Figure 3 、 Figures 7 to 10 , the first current collector 241 has a first region 2411 for connecting the first tab 2221 and a first connection region 2412 for connecting the first electrode terminal 231, and the second current collector 242 has a second region 2421 for connecting the second tab 2222 and a second connection region 2422 for connecting the second electrode terminal 232; the overall dimension from the first region 2411 to the first connection region 2412 is smaller than the overall dimension from the second region 2421 to the second connection region 2422, and the ratio of the internal resistance of the first region 2411 to the first connection region 2412 to the internal resistance of the second region 2421 to the second connection region 2422 ranges from 95% to 105%.

[0111] Since the tabs 222 of the electrode assembly 22 are often formed by overlapping a plurality of sheet-like structures, the connection between the tabs 222 and the current collector 24, such as welding, is often a region. The cross-section of the electrode terminal 23 often has a certain area. Therefore, the connection position between the current collector 24 and the electrode terminal 23 is also a region. That is to say, the position on the first current collector 241 connected to the first tab 2221 is a region, and this region is the first region 2411, that is, the first region 2411 is the region on the first current collector 241 connected to the first tab 2221. The position on the first current collector 241 connected to the first electrode terminal 231 is a region, and this region is the first connection region 2412, that is, the first connection region 2412 is the region on the first current collector 241 connected to the first connection region 2412. The position on the second current collector 242 connected to the second tab 2222 is a region, and this region is the second region 2421, that is, the second region 2421 is the region on the second current collector 242 connected to the second tab 2222. The position on the second current collector 242 connected to the second electrode terminal 232 is a region, and this region is the second connection region 2422, that is, the second connection region 2422 is the region on the second current collector 242 connected to the second connection region 2422.

[0112] Under the condition that the conductive component has the same material and working environment, its current-carrying capacity is mainly related to its thickness and length. Also under the condition that the conductive component has the same material and working environment, its internal resistance is mainly related to its thickness and length. Therefore, there is a direct relationship between the current-carrying capacity and the internal resistance of the conductive component. The current-carrying capacity refers to the maximum current capacity of the conductive component to safely transmit without damage when it bears a current exceeding the normal working current. The internal resistance refers to the resistance inside the conductive component, which affects the energy loss and temperature rise when current passes through. In an ideal situation, the conductive component should have as low an internal resistance as possible, so that it can transmit current more effectively while reducing the energy dissipated in the form of heat. A low internal resistance means that under the same current, the voltage drop across the conductive component is smaller and the temperature rise is relatively lower, which enables the conductive component to withstand a higher current without overheating or being damaged. On the contrary, if the internal resistance of the conductive component is high, when current passes through, according to Joule's law, the higher internal resistance will cause more energy to be released in the form of heat, which may lead to a sharp increase in the temperature of the conductive component, or even cause it to melt or be damaged. Therefore, a high internal resistance limits the current-carrying capacity of the conductive component. That is to say, the lower the internal resistance of the conductive component, the stronger its current-carrying capacity; on the contrary, the higher the internal resistance of the conductive component, the weaker its current-carrying capacity. Thus, the current-carrying capacity of the conductive component can be improved by reducing its internal resistance. According to Ohm's law, the resistance R of the conductive component is directly proportional to its length L and resistivity ρ, and inversely proportional to its cross-sectional area S. In this way, the internal resistance of the conductive component can be adjusted by changing its dimensions, and thus its current-carrying capacity can be adjusted.

[0113] It should be noted that in the original text, it is "According to the resistance law", but in the translation, it should be "According to Ohm's law" for the correct physical law expression.During the charge and discharge process of the battery cell 200, the current path between the first electrode terminal 231 and the first tab 2221 is as follows: the first electrode terminal 231, the first tab 2221, the first connection area 2412, the first region 2411, and the path formed by the part between the first connection area 2412 and the first region 2411. Therefore, without considering the current-carrying capacity of the first electrode terminal 231 and the first tab 2221, the overall current-carrying capacity of the part between the first connection area 2412 and the first region 2411, the first connection area 2412, and the first region 2411 on the first current collector 241 determines the current-carrying capacity between the first electrode terminal 231 and the first tab 2221. And the overall internal resistance of the part between the first connection area 2412 and the first region 2411, the first connection area 2412, and the first region 2411 determines the overall current-carrying capacity of the part between the first connection area 2412 and the first region 2411, the first connection area 2412, and the first region 2411. Thus, reducing the overall size of the part between the first connection area 2412 and the first region 2411, the first connection area 2412, and the first region 2411 can increase the overall internal resistance of the part between the first connection area 2412 and the first region 2411, the first connection area 2412, and the first region 2411, while reducing the current-carrying capacity between the first electrode terminal 231 and the first tab 2221.

[0114] Similarly, during the overcurrent charge and discharge of the battery cell 200, the current path between the second electrode terminal 232 and the second tab 2222 is as follows: the second electrode terminal 232, the second tab 2222, the second connection area 2422, the second region 2421, and the path formed by the part between the second connection area 2422 and the second region 2421. Therefore, without considering the current-carrying capacity of the second electrode terminal 232 and the second tab 2222, the overall current-carrying capacity of the part between the second connection area 2422 and the second region 2421, the second connection area 2422, and the second region 2421 on the second current collector 242 determines the current-carrying capacity between the second electrode terminal 232 and the second tab 2222. And the overall internal resistance of the part between the second connection area 2422 and the second region 2421, the second connection area 2422, and the second region 2421 determines the overall current-carrying capacity of the part between the second connection area 2422 and the second region 2421, the second connection area 2422, and the second region 2421.

[0115] The whole from the first region 2411 to the first connection area 2412 refers to the whole formed by the part between the first connection area 2412 and the first region 2411, the first connection area 2412, and the first region 2411 on the first current collector 241.

[0116] The entirety from the second region 2421 to the second connection region 2422 refers to the part between the second connection region 2422 and the second region 2421 on the second current collector 242, the second connection region 2422, and the entirety formed by the second region 2421.

[0117] The internal resistance from the first region 2411 to the first connection region 2412 refers to the internal resistance of the part between the first connection region 2412 and the first region 2411 on the first current collector 241, the first connection region 2412, and the entirety formed by the first region 2411, and is also the resistance between the first electrode terminal 231 and the first tab 2221.

[0118] The internal resistance from the second region 2421 to the second connection region 2422 refers to the internal resistance of the part between the second connection region 2422 and the second region 2421 on the second current collector 242, the second connection region 2422, and the entirety formed by the second region 2421, and is also the resistance between the second electrode terminal 232 and the second tab 2222.

[0119] The internal resistance from the first region 2411 to the first connection region 2412 tends to be consistent with the internal resistance from the second region 2421 to the second connection region 2422, which can also be called that the internal resistance from the first region 2411 to the first connection region 2412 is approximately equal to the internal resistance from the second region 2421 to the second connection region 2422. It means that the difference between the internal resistance from the first region 2411 to the first connection region 2412 and the internal resistance from the second region 2421 to the second connection region 2422 is within 5%. For example, the internal resistance R1 from the first region 2411 to the first connection region 2412 is 5% or less greater than the internal resistance R2 from the second region 2421 to the second connection region 2422, that is: (R1 - R2) / R2 ≤ 5%; or, the internal resistance R1 from the first region 2411 to the first connection region 2412 is 5% or less smaller than the internal resistance R2 from the second region 2421 to the second connection region 2422, that is: (R2 - R1) / R1 ≤ 5%; or, the internal resistance R1 from the first region 2411 to the first connection region 2412 is equal to the internal resistance R2 from the second region 2421 to the second connection region 2422. The range of the ratio of the internal resistance from the first region 2411 to the first connection region 2412 to the internal resistance from the second region 2421 to the second connection region 2422 is 95% - 105%. For example, the ratio of the internal resistance from the first region 2411 to the first connection region 2412 to the internal resistance from the second region 2421 to the second connection region 2422 is 95%, 96%, 97%, 98%, 99%, 100%, 101%, 102%, 103%, 104%, 105%, etc. That is, it can be considered that the internal resistance from the first region 2411 to the first connection region 2412 tends to be consistent with the internal resistance from the second region 2421 to the second connection region 2422, or it can be considered that the internal resistance from the first region 2411 to the first connection region 2412 is approximately equal to the internal resistance from the second region 2421 to the second connection region 2422.

[0120] A first region 2411 is provided to facilitate the connection between the first current collector 241 and the first tab 2221, and a first connection region 2412 is provided to facilitate the connection between the first current collector 241 and the first electrode terminal 231; a second region 2421 is provided to facilitate the connection between the second current collector 242 and the second tab 2222, and a second connection region 2422 is provided to facilitate the connection between the second current collector 242 and the second electrode terminal 232; in addition, by making the overall dimension from the first region 2411 to the first connection region 2412 smaller than the overall dimension from the second region 2421 to the second connection region 2422, such as reducing the area of the first region 2411, and / or reducing the area of the first connection region 2412, and / or reducing the thickness h1 of the first current collector 241, etc., the cross-section of the current flow path in the first current collector 241 can be reduced, so as to set the overall dimension from the first region 2411 to the first connection region 2412 to be smaller, so as to make the internal resistance of the first region 2411 to the first connection region 2412 tend to be the same as that of the second region 2421 to the second connection region 2422, and further make the overcurrent capacity of the first region 2411 to the first connection region 2412 approximately equal to that of the second region 2421 to the second connection region 2422, so as to meet the overcurrent requirements of charging and discharging of the battery cell 200, and the dimensions of the part of the first current collector 241 outside the first region 2411 to the first connection region 2412 can be set to be smaller, so as to reduce the size of the first current collector 241, and further reduce the overall size and weight of the current collector 24, and improve the energy density of the battery cell 200. In addition, according to this design structure, the second current collector 242 can be better utilized, and the dimensions of the part of the second current collector 242 outside the second region 2421 to the second connection region 2422 can be set to be smaller, so as to reduce the size of the second current collector 242, and further reduce the overall size and weight of the current collector 24.

[0121] In some embodiments, please refer to Figure 3 、 Figures 7 to 10 , along the thickness direction H of the current collector 24, the overall projected area from the first region 2411 to the first connection region 2412 is smaller than the overall projected area from the second region 2421 to the second connection region 2422, so that the internal resistance of the first region 2411 to the first connection region 2412 tends to be the same as that of the second region 2421 to the second connection region 2422.

[0122] The overall projected area from the first region 2411 to the first connection region 2412 refers to the area of the projection of the whole formed by the part between the first connection region 2412 and the first region 2411, the first connection region 2412, and the first region 2411 along the thickness direction H of the current collector 24. Since the current flows from the first region 2411 to the first connection region 2412, if there is an overlap in the projections of the first connection region 2412 and the first region 2411 along the thickness direction of the current collector 24, the length of the conductive part formed by the whole from the first region 2411 to the first connection region 2412 is generally the thickness h1 of the first current collector part 241; the overall projected area from the first region 2411 to the first connection region 2412 can form the largest cross-section of the whole formed by the part between the first connection region 2412 and the first region 2411, the first connection region 2412, and the first region 2411. In this case, the smaller the overall projected area from the first region 2411 to the first connection region 2412, the greater the internal resistance of the whole formed by the part between the first connection region 2412 and the first region 2411, the first connection region 2412, and the first region 2411, and the weaker the current-carrying capacity between the first tab 2221 and the first electrode terminal 231. If the projections of the first connection region 2412 and the first region 2411 are spaced apart along the thickness direction of the current collector 24, the length of the conductive part formed by the whole from the first region 2411 to the first connection region 2412 is generally the length from the first region 2411 along an inclination to the first connection region 2412 in the thickness direction H of the first current collector part 241, and this length is much greater than the thickness h1 of the first current collector part 241. Then, at this time, the internal resistance of the whole from the first region 2411 to the first connection region 2412 can be increased by reducing the area of the first region 2411, and / or reducing the area of the first connection region 2412, and / or reducing the thickness h1 of the first current collector part 241, etc., so as to weaken the current-carrying capacity between the first tab 2221 and the first electrode terminal 231.

[0123] The overall projected area of the second region 2421 to the second connection region 2422 refers to the area of the projection of the whole formed by the part between the second connection region 2422 and the second region 2421, the second connection region 2422, and the second region 2421 along the thickness direction H of the current collector 24. Since the current flows from the second region 2421 to the second connection region 2422, if there is an overlap in the projections of the second connection region 2422 and the second region 2421 along the thickness direction H of the current collector 24, the length of the conductive part formed by the whole of the second region 2421 to the second connection region 2422 is generally the thickness of the second current collector part 242; the overall projected area of the second region 2421 to the second connection region 2422 can form the maximum cross-section of the whole formed by the part between the second connection region 2422 and the second region 2421, the second connection region 2422, and the second region 2421. In this case, the smaller the overall projected area of the second region 2421 to the second connection region 2422, the greater the internal resistance of the whole formed by the part between the second connection region 2422 and the second region 2421, the second connection region 2422, and the second region 2421, and the weaker the current-carrying capacity between the second tab 2222 and the second electrode terminal 232. If the projections of the second connection region 2422 and the second region 2421 are spaced apart along the thickness direction H of the current collector 24, the length of the conductive part formed by the whole of the second region 2421 to the second connection region 2422 is generally the length from the second region 2421 along an inclination to the second connection region 2422 in the thickness direction of the second current collector part 242, and this length is much greater than the thickness of the second current collector part 242. Then, in this case, the internal resistance of the whole of the second region 2421 to the second connection region 2422 can be reduced by increasing the area of the second region 2421, and / or increasing the area of the second connection region 2422, and / or increasing the thickness h2 of the second current collector part 242, etc., so as to enhance the current-carrying capacity between the second tab 2222 and the second electrode terminal 232.

[0124] In this way, by adjusting the overall projected area of the first region 2411 to the first connection region 2412 and / or the overall projected area of the second region 2421 to the second connection region 2422, the internal resistance of the first region 2411 to the first connection region 2412 is made to tend to be the same as the internal resistance of the second region 2421 to the second connection region 2422.

[0125] The overall projected area from the first region 2411 to the first connection region 2412 is set to be smaller, so as to increase the internal resistance from the first region 2411 to the first connection region 2412. Furthermore, it can make the internal resistance from the first region 2411 to the first connection region 2412 tend to be consistent with the internal resistance from the second region 2421 to the second connection region 2422, thereby achieving that the overcurrent capacity from the first region 2411 to the first connection region 2412 is approximately equal to the overcurrent capacity from the second region 2421 to the second connection region 2422, to meet the overcurrent requirements for charging and discharging of the battery cell 200. And the dimensions of the part of the first current collector 241 outside the first region 2411 to the first connection region 2412 can be set to be smaller, so as to reduce the size of the first current collector 241, and further reduce the overall size and weight of the current collector 24, and improve the energy density of the battery cell 200.

[0126] In some embodiments, please refer to Figure 3 、 Figures 7 to 10 , the area of the first region 2411 is smaller than the area of the second region 2421.

[0127] Since the first region 2411 is located on one side of the first current collector 241, the area of the first region 2411 is approximately equal to the projected area of the first region 2411 along the thickness direction H of the current collector 24. Since the second region 2421 is located on one side of the second current collector 242, the area of the second region 2421 is approximately equal to the projected area of the second region 2421 along the thickness direction H of the current collector 24.

[0128] The area of the first region 2411 is at least a part of the overall projected area from the first region 2411 to the first connection region 2412; the area of the second region 2421 is at least a part of the overall projected area from the second region 2421 to the second connection region 2422; then setting the area of the first region 2411 to be smaller than the area of the second region 2421 can increase the overall internal resistance from the first region 2411 to the first connection region 2412, so that the overall internal resistance from the first region 2411 to the first connection region 2412 is approximately equal to the overall internal resistance from the second region 2421 to the second connection region 2422, and make the overcurrent capacity from the first region 2411 to the first connection region 2412 approximately equal to the overcurrent capacity from the second region 2421 to the second connection region 2422, to meet the overcurrent requirements for charging and discharging of the battery cell 200. And the overall size from the first region 2411 to the first connection region 2412 can also be set to be smaller, and then the size of the first current collector 241 can be made smaller, and further reduce the overall size and weight of the current collector 24, and improve the energy density of the battery cell 200.

[0129] In some embodiments, when the first region 2411 is rectangular, please refer to Figure 8, the length L1 of the first region 2411 can be set to be less than the length L2 of the second region 2421, and the width W1 of the first region 2411 is less than or equal to the width W2 of the second region 2421, so that the area of the first region 2411 is set to be less than the area of the second region 2421. Please refer to Figure 9 , the width W1 of the first region 2411 can be set to be less than the width W2 of the second region 2421, and the length L1 of the first region 2411 is less than or equal to the length L2 of the second region 2421, so that the area of the first region 2411 is set to be less than the area of the second region 2421.

[0130] In some embodiments, the overall thickness of the first region 2411 to the first connection region 2412 can also be set to be less than the overall thickness of the second region 2421 to the second connection region 2422, so that the overall size of the first region 2411 to the first connection region 2412 is less than the overall size of the second region 2421 to the second connection region 2422, and further the internal resistance of the first region 2411 to the first connection region 2412 tends to be consistent with the internal resistance of the second region 2421 to the second connection region 2422.

[0131] In some embodiments, please refer to Figure 3 、 Figures 6 to 9 , along the thickness direction H of the current collector 24, the projection of the first connection region 2412 coincides with at least a part of the first region 2411, and / or the projection of the second connection region 2422 coincides with at least a part of the second region 2421.

[0132] Making the projection of the first connection region 2412 coincide with at least a part of the first region 2411 can make the path of the current from the first region 2411 to the first connection region 2412 shorter. The length of this path is approximately the thickness h1 of the first current collector part 241, which can reduce the internal resistance of the first region 2411 to the first connection region 2412, improve the overcurrent capacity. Furthermore, when the overcurrent capacity of the first region 2411 to the first connection region 2412 meets the requirements, the overall size of the first region 2411 to the first connection region 2412 can be made smaller, and then the size of the first current collector part 241 can be made smaller, so as to reduce the material usage of the first current collector part 241, improve the material utilization rate, and reduce the weight, thereby improving the energy density of the battery cell 200. In addition, this structure also facilitates adjusting the internal resistance of the first region 2411 to the first connection region 2412 by adjusting the area of the first connection region 2412 and / or the area of the first region 2411, so as to make the internal resistance of the first region 2411 to the first connection region 2412 tend to be consistent with the internal resistance of the second region 2421 to the second connection region 2422.

[0133] Overlapping at least partially the projection of the second connection region 2422 with the second region 2421 can make the path for current to flow from the second region 2421 to the second connection region 2422 shorter. The length of this path is approximately the thickness h1 of the first current collector portion 241, which can reduce the internal resistance from the second region 2421 to the second connection region 2422, improve the overcurrent capacity. Then, when the overcurrent capacity from the second region 2421 to the second connection region 2422 meets the requirements, the overall size of the second region 2421 to the second connection region 2422 can be made smaller. Consequently, the size of the second current collector portion 242 can be made smaller, reducing the material usage of the second current collector portion 242, improving the material utilization rate, and reducing the weight, thereby enhancing the energy density of the battery cell 200. Additionally, this structure also facilitates adjusting the internal resistance from the second region 2421 to the second connection region 2422 by adjusting the area of the second connection region 2422 and / or the area of the second region 2421, so as to make the internal resistance from the first region 2411 to the first connection region 2412 tend to be consistent with the internal resistance from the second region 2421 to the second connection region 2422.

[0134] In some embodiments, referring to Figure 3 and Figure 10 , along the thickness direction H of the current collector member 24, the projection of the first connection region 2412 is spaced apart from the first region 2411, and the projection of the second connection region 2422 is spaced apart from the second region 2421. The distance J1 between the projection of the first connection region 2412 and the first region 2411 is greater than or equal to the distance J2 between the projection of the second connection region 2422 and the second region 2421.

[0135] Spacing apart the projection of the first connection region 2412 from the first region 2411 facilitates the positional distribution of the first connection region 2412 and the first region 2411; spacing apart the projection of the second connection region 2422 from the second region 2421 facilitates the positional distribution of the second connection region 2422 and the second region 2421; setting the distance J1 between the projection of the first connection region 2412 and the first region 2411 to be larger can increase the overall internal resistance from the first region 2411 to the first connection region 2412, so as to make the internal resistance from the first region 2411 to the first connection region 2412 tend to be consistent with the internal resistance from the second region 2421 to the second connection region 2422.

[0136] Due to the limited internal space of the battery cell 200, the sizes of the first current collector portion 241 and the second current collector portion 242 are also limited. Correspondingly, the distance J1 between the projection of the first connection region 2412 and the first region 2411 is limited, and the distance J2 between the projection of the second connection region 2422 and the second region 2421 is also limited. Therefore, by adjusting the distance J1 between the projection of the first connection region 2412 and the first region 2411 to adjust the overall internal resistance from the first region 2411 to the first connection region 2412, it is often only a fine adjustment, and other methods are often required to be combined, such as adjusting the thickness h1 of the first current collector portion 241, adjusting the area of the first connection region 2412, adjusting the area of the first region 2411, etc., to adjust the overall internal resistance from the first region 2411 to the first connection region 2412, so as to make the internal resistance setting from the first region 2411 to the first connection region 2412 tend to be consistent with the internal resistance from the second region 2421 to the second connection region 2422. Similarly, by adjusting the distance J2 between the projection of the second connection region 2422 and the second region 2421 to adjust the overall internal resistance from the second region 2421 to the second connection region 2422, it is often only a fine adjustment, and other methods are often required to be combined, such as adjusting the thickness h2 of the second current collector portion 242, adjusting the area of the second connection region 2422, adjusting the area of the second region 2421, etc., to adjust the overall internal resistance from the second region 2421 to the second connection region 2422.

[0137] By arranging the projection of the first connection region 2412 at an interval from the first region 2411 and arranging the projection of the second connection region 2422 at an interval from the second region 2421 to finely adjust the overall internal resistance from the first region 2411 to the first connection region 2412 and the overall internal resistance from the second region 2421 to the second connection region 2422, the internal resistance setting from the first region 2411 to the first connection region 2412 can be made to better tend to be equal to the internal resistance from the second region 2421 to the second connection region 2422.

[0138] In some embodiments, please refer to Figures 3 to 10 , the thickness h1 of the first current collector portion 241 is less than the thickness h2 of the second current collector portion 242.

[0139] Since the current collector member 24 is located between the electrode assembly 22 and the electrode terminal 23, and the current generally flows in the thickness direction H of the current collector member 24 between the tab 222 and the electrode terminal 23 in the current collector member 24, the thickness of the current collector member 24 determines the cross-section of the current collector member 24.

[0140] The first current collector 241 connects the first tab 2221 and the first electrode terminal 231. By adjusting the thickness h1 of the first current collector 241, the internal resistance of the first current collector 241 can be adjusted, and further the current-carrying capacity of the first current collector 241 can be adjusted. For example, the smaller the thickness h1 of the first current collector 241 is set, the greater the internal resistance of the first current collector 241 is, and the weaker the current-carrying capacity of the first current collector 241 is. When the first current collector 241 is provided with a first region 2411 and a first connection region 2412, adjusting the thickness h1 of the first current collector 241 is also to adjust the thickness of the part between the first connection region 2412 and the first region 2411, and the overall thickness formed by the first connection region 2412 and the first region 2411. And the smaller the thickness h1 of the first current collector 241 is set, the greater the overall internal resistance from the first region 2411 to the first connection region 2412 is, and the weaker the current-carrying capacity from the first region 2411 to the first connection region 2412 is. Correspondingly, the current-carrying capacity between the first electrode terminal 231 and the first tab 2221 is weaker.

[0141] The second current collector 242 connects the second tab 2222 and the second electrode terminal 232. By adjusting the thickness h2 of the second current collector 242, the internal resistance of the second current collector 242 can be adjusted, and further the current-carrying capacity of the second current collector 242 can be adjusted. For example, the larger the thickness h2 of the second current collector 242 is set, the smaller the internal resistance of the second current collector 242 is, and the weaker the current-carrying capacity of the second current collector 242 is. When the second current collector 242 is provided with a second region 2421 and a second connection region 2422, adjusting the thickness h2 of the second current collector 242 is also to adjust the thickness of the part between the second connection region 2422 and the second region 2421, and the overall thickness formed by the second connection region 2422 and the second region 2421. And the larger the thickness h2 of the second current collector 242 is set, the smaller the overall internal resistance from the second region 2421 to the second connection region 2422 is, and the stronger the current-carrying capacity from the second region 2421 to the second connection region 2422 is. Correspondingly, the current-carrying capacity between the second electrode terminal 232 and the second tab 2222 is stronger.

[0142] The thickness h1 of the first current collector 241 is set to be smaller so as to make the current-carrying capacity of the first current collector 241 tend to be consistent with that of the second current collector 242, reduce the usage amount of the first material, make better use of the first material, improve the utilization rate of the first material, and reduce the weight of the current collector 24, thereby improving the energy density of the battery cell 200.

[0143] In some embodiments, please refer to Figure 3 and Figure 6, in the direction from the first current collector part 241 to the second current collector part 242, the thickness of the current collector member 24 is gradually increased, so that the overall thickness of the first current collector part 241 can be set to be less than the overall thickness of the second current collector part 242, thereby facilitating the setting of the current-carrying capacity of the first current collector part 241 to be consistent with that of the second current collector part 242.

[0144] In addition, setting the thickness of the current collector member 24 to be gradually variable is convenient for design, and also convenient for setting the current-carrying capacity of the first current collector part 241 to be consistent with that of the second current collector part 242. Moreover, it can reduce the usage amount of the first material, make better use of the first material, improve the utilization rate of the first material, and reduce the weight of the current collector member 24, thereby improving the energy density of the battery cell 200.

[0145] In some embodiments, please refer to Figures 3 to 5 , one side of the current collector member 24 facing away from the electrode assembly 22 is flat, and one side of the current collector member 24 facing the electrode assembly 22 is stepped.

[0146] The stepped shape refers to a shape or structure similar to a staircase.

[0147] Setting one side of the current collector member 24 facing away from the electrode assembly 22 to be flat is convenient for connecting with the electrode terminal 23. And setting one side of the current collector member 24 facing the electrode assembly 22 to be stepped can facilitate setting the thickness h1 of the first current collector part 241 to be smaller, thereby making the current-carrying capacity of the first current collector part 241 consistent with that of the second current collector part 242. Moreover, it can reduce the usage amount of the first material, make better use of the first material, improve the utilization rate of the first material, and reduce the weight of the current collector member 24, thereby improving the energy density of the battery cell 200.

[0148] In some embodiments, please refer to Figures 3 to 5 , the thickness h3 of the insulating part 243 is greater than or equal to the thickness h1 of the first current collector part 241, and the thickness h3 of the insulating part 243 is less than or equal to the thickness h2 of the second current collector part 242.

[0149] Setting the thickness h3 of the insulating part 243 to be greater than or equal to the thickness h1 of the first current collector part 241 can enable the insulating part 243 to be well-connected and fixed with the first current collector part 241, and well-insulate the side of the first current collector part 241 close to the second current collector part 242. Setting the thickness h3 of the insulating part 243 to be less than or equal to the thickness h2 of the second current collector part 242 can make the overall thickness of the current collector member 24 smaller, so as to reduce the space occupied in the battery cell 200.

[0150] In addition, setting the thickness h3 of the insulating part 243 can better insulate and separate the first current collector part 241 from the second current collector part 242, and is also convenient for the design and manufacture of the insulating part 243.

[0151] In some embodiments, referring to Figure 3 、 Figure 8 、 Figure 9 and Figure 12 , along the thickness direction H of the current collector 24, the projected area of the first current collecting portion 241 is smaller than the projected area of the second current collecting portion 242.

[0152] The projected area of the first current collecting portion 241 along the thickness direction H of the current collector 24 is directly related to the cross-section through which the current flows in the current path in the first current collecting portion 241. Therefore, the smaller the projected area of the first current collecting portion 241 along the thickness direction, the greater the internal resistance of the first current collecting portion 241.

[0153] The projected area of the second current collecting portion 242 along the thickness direction H of the current collector 24 is directly related to the cross-section through which the current flows in the current path in the second current collecting portion 242. Therefore, the smaller the projected area of the second current collecting portion 242 along the thickness direction, the greater the internal resistance of the second current collecting portion 242.

[0154] Setting the projected area of the first current collecting portion 241 along the thickness direction to be smaller can make the size of the first current collecting portion 241 smaller, so as to make the current-carrying capacity of the first current collecting portion 241 tend to be consistent with that of the second current collecting portion 242, and reduce the usage amount of the first material, make better use of the first material, improve the utilization rate of the first material, and reduce the weight of the current collector 24, thereby improving the energy density of the battery cell 200.

[0155] In some embodiments, the first material is copper and the second material is aluminum.

[0156] Copper refers to metallic copper material. Aluminum refers to metallic aluminum material.

[0157] Using copper as the first material, that is, the first current collecting portion 241 is made of copper, and using aluminum as the second material, that is, the second current collecting portion 242 is made of aluminum, is convenient for design and processing.

[0158] In some embodiments, referring to Figure 3 and Figure 11 , the shape of the current collector 24 is adapted to the shape of the end of the main body portion 221 where the first tab 2221 is led out.

[0159] The shape of the current collector 24 is the shape of the projection along the thickness direction H of the current collector 24.

[0160] The end of the main body portion 221 where the first tab 2221 is led out refers to the end of the main body portion 221 where the tab 222 is located.

[0161] The shape of the current collector 24 is set to match the shape of the end of the main body 221 of the electrode assembly 22 where the tab 222 is located, facilitating the mating connection between the current collector 24 and the tab 222, increasing the connection area between the tab 222 and the current collector 24. For example, it can increase the connection area between the first tab 2221 and the first current collecting portion 241, improve the connection strength between the first current collecting portion 241 and the first tab 2221, and reduce the internal resistance of the connection between the first tab 2221 and the first current collecting portion 241. Similarly, it can also increase the connection area between the second tab 2222 and the second current collecting portion 242, improve the connection strength between the second current collecting portion 242 and the second tab 2222, and reduce the internal resistance of the connection between the second tab 2222 and the second current collecting portion 242, thereby reducing the internal resistance of the battery cell 200 and improving the charge and discharge performance of the battery cell 200.

[0162] In some embodiments, referring to Figure 3 , the battery cell 200 is square, and the current collector 24 is in the shape of a rectangular sheet.

[0163] The battery cell 200 being square means that each side of the battery cell 200 is rectangular, and the battery cell 200 as a whole is in the shape of a cuboid.

[0164] The current collector 24 being in the shape of a rectangular sheet means that the current collector 24 is a flat sheet structure and its shape is rectangular.

[0165] When the battery cell 200 is square, the current collector 24 is set to be in the shape of a rectangular sheet to better apply to the battery cell 200, so as to increase the contact area between the current collector 24 and the tab 222 of the electrode assembly 22, facilitate connection, and also reduce the internal resistance of the battery cell 200 and improve the charge and discharge performance of the battery cell 200.

[0166] In some embodiments, referring to Figure 11 , the battery cell 200 is cylindrical, and the current collector 24 is in the shape of a disc.

[0167] Cylindrical means that the overall shape of the battery cell 200 is cylindrical.

[0168] Disc-shaped means that the overall is a flat structure and its projection along the thickness direction is circular.

[0169] When the battery cell 200 is cylindrical, the current collector 24 is set to be in the shape of a disc to better apply to the battery cell 200, so as to increase the contact area between the current collector 24 and the tab 222 of the electrode assembly 22, facilitate connection, and also reduce the internal resistance of the battery cell 200 and improve the charge and discharge performance of the battery cell 200.

[0170] According to some embodiments of the present application, the present application provides a battery cell 200, which includes an electrode assembly 22, a first electrode terminal 231, a second electrode terminal 232, and a current collector 24. The electrode assembly 22 includes a main body portion 221. A first tab 2221 and a second tab 2222 are led out from the same side of the main body portion 221, and the polarities of the first tab 2221 and the second tab 2222 are opposite; the first electrode terminal 231 is used to electrically connect the first tab 2221; the second electrode terminal 232 is used to electrically connect the second tab 2222; the current collector 24 includes a first current collecting portion 241 made of a first material, a second current collecting portion 242 made of a second material, and an insulating portion 243 connecting the first current collecting portion 241 and the second current collecting portion 242. The conductivity of the first material is greater than that of the second material. The first current collecting portion 241 connects the first electrode terminal 231 and the first tab 2221, and the second current collecting portion 242 connects the second electrode terminal 232 and the second tab 2222; the thickness h1 of the first current collecting portion 241 is less than the thickness h2 of the second current collecting portion 242, so that the current-carrying capacity of the first current collecting portion 241 is consistent with that of the second current collecting portion 242.

[0171] The thickness h1 of the first current collecting portion 241 made of a material with a higher conductivity is set to be smaller, so as to make the current-carrying capacity of the first current collecting portion 241 consistent with that of the second current collecting portion 242, reduce the usage amount of the first material, make better use of the first material, improve the utilization rate of the first material, and reduce the weight of the current collector 24, thereby improving the energy density of the battery cell 200.

[0172] According to some embodiments of the present application, the present application further provides a battery, which includes the battery cell 200 described in any of the above solutions.

[0173] According to some embodiments of the present application, the present application further provides an electrical device, which includes the battery described in any of the above solutions.

[0174] The electrical device can be any of the aforementioned devices or systems using the battery.

[0175] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some or all of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the various embodiments of the present application, and they should all be covered by the scope of the claims and the description of the present application. In particular, as long as there is no structural conflict, the various technical features mentioned in each embodiment can be combined in any way. The present application is not limited to the specific embodiments disclosed in the text, but includes all technical solutions that fall within the scope of the claims.

Claims

1. A battery cell, characterized in that, Comprising: An electrode assembly including a main body portion, a first tab and a second tab being led out from the same side of the main body portion, the first tab and the second tab having opposite polarities; A first electrode terminal for electrically connecting the first tab; A second electrode terminal for electrically connecting the second tab; And, A current collector including a first current collecting portion made of a first material, a second current collecting portion made of a second material, and an insulating portion connecting the first current collecting portion and the second current collecting portion, the first current collecting portion connecting the first electrode terminal and the first tab, and the second current collecting portion connecting the second electrode terminal and the second tab; The conductivity of the first material is greater than that of the second material, the size of the first current collecting portion is smaller than that of the second current collecting portion, and the ratio of the internal resistance of the first current collecting portion to the internal resistance of the second current collecting portion ranges from 95% to 105%.

2. The battery cell according to claim 1, wherein The first current collecting portion has a first area for connecting the first tab and a first connection area for connecting the first electrode terminal, and the second current collecting portion has a second area for connecting the second tab and a second connection area for connecting the second electrode terminal; The overall size from the first area to the first connection area is smaller than the overall size from the second area to the second connection area, and the ratio of the internal resistance from the first area to the first connection area to the internal resistance from the second area to the second connection area ranges from 95% to 105%.

3. The battery cell according to claim 2, characterized in that, In the thickness direction of the current collector, the overall projected area from the first area to the first connection area is smaller than the overall projected area from the second area to the second connection area.

4. The battery cell according to claim 3, wherein, The area of the first area is smaller than the area of the second area.

5. The battery cell according to any one of claims 2-4, characterized in that, In the thickness direction of the current collector, the projection of the first connection area at least partially coincides with the first area, and / or the projection of the second connection area at least partially coincides with the second area.

6. The battery cell according to any one of claims 2-4, characterized in that, In the thickness direction of the current collector, the projection of the first connection area is spaced from the first area, the projection of the second connection area is spaced from the second area, and the distance between the projection of the first connection area and the first area is greater than or equal to the distance between the projection of the second connection area and the second area.

7. The battery cell according to any one of claims 1-6, characterized in that, The thickness of the first current collecting portion is smaller than the thickness of the second current collecting portion.

8. The battery cell according to claim 7, wherein In the direction from the first current collecting portion to the second current collecting portion, the thickness of the current collector is gradually increasing.

9. The battery cell according to claim 7, wherein, The surface of the current collector facing away from the electrode assembly is planar, and the surface of the current collector facing the electrode assembly is stepped.

10. The battery cell according to claim 9, characterized in that, The thickness of the insulating portion is greater than or equal to the thickness of the first current collecting portion and less than or equal to the thickness of the second current collecting portion.

11. The battery cell according to any one of claims 1-10, characterized in that, In the thickness direction of the current collector, the projected area of the first current collecting portion is smaller than the projected area of the second current collecting portion.

12. The battery cell according to any one of claims 1-11, characterized in that, The first material is copper and the second material is aluminum.

13. The battery cell according to any one of claims 1-12, characterized in that, The shape of the current collector is adapted to the shape of the end of the main body portion where the first tab is led out.

14. The battery cell according to claim 13, characterized in that, The battery cell is square, and the current collector is rectangular sheet-shaped; or the battery cell is cylindrical, and the current collector is disc-shaped.

15. A battery, characterized in that, It includes the battery cell according to any one of claims 1-14.

16. An electrical device, characterized in that, It includes the battery according to claim 15.

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