Battery monomer, battery device, power utilization device and energy storage device

Abstract

The utility model discloses a battery monomer, a battery device, a power utilization device and an energy storage device. The battery cell includes a housing and an electrode assembly. The shell comprises a shell body with an opening and an end cover covering the opening. The electrode assembly is located within the housing. The electrode assembly comprises an electrode main body and a tab connected with the electrode main body. The electrode main body comprises a positive plate, a negative plate and a separator which are stacked in a first direction; wherein the length of the end cover in the second direction is within the range of 320 mm to 480 mm, and the ratio of the minimum width of the tab in the second direction to the length of the end cover in the second direction is within the range of 0.23 to 0.35. The tab of the battery monomer is wide enough, so that the overcurrent capability of the battery monomer is improved, the energy conversion efficiency of the battery monomer is improved, and the heat dissipation performance is good. In addition, the width of the tab is in a proper range, so that other structures of the end cover are not easily influenced, and the reliability of the single battery is favorably improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of batteries, in particular to a battery monomer, a battery device, a power utilization device and an energy storage device. BACKGROUND

[0002] New energy batteries are increasingly widely used in life and industry. For example, new energy vehicles equipped with batteries have been widely used. In addition, batteries are also increasingly used in the field of energy storage and the like.

[0003] With the continuous development of battery technology, how to improve the energy conversion efficiency of the battery monomer is one of the research topics in the industry. CONTENT OF THE UTILITY MODEL

[0004] To solve the above technical problems, the present application provides a battery monomer, a battery device, a power utilization device and an energy storage device with strong overcurrent capacity and high energy conversion efficiency.

[0005] The present application is implemented by the following technical solutions.

[0006] The first aspect of the present application provides a battery monomer, which comprises: a shell comprising a shell body with an opening and an end cover arranged at the opening; and an electrode assembly located in the shell, the electrode assembly comprising an electrode main body and a tab connected to the electrode main body, the electrode main body comprising a positive electrode sheet, a negative electrode sheet and a separator arranged in a stack along a first direction; wherein the length of the end cover along a second direction is in the range of 320mm to 480mm, and the ratio of the minimum width of the tab along the second direction to the length of the end cover along the second direction is in the range of 0.23 to 0.35, and the second direction intersects the first direction.

[0007] Therefore, the width of the tab along the second direction is in a suitable range, which can increase the flow area of the current, thereby reducing the electron transmission impedance, and further helping to reduce the energy loss of the battery monomer during charging and discharging, and improving the energy conversion efficiency of the battery monomer. Moreover, the width of the tab is in a suitable range, so that the tab can carry a larger current, and the distribution of the current is more uniform, reducing local heat accumulation caused by current concentration, and also enabling the battery monomer to better meet the output demand of high power during high-rate discharge, thereby helping the battery monomer to stably discharge, reducing the polarization phenomenon caused by excessive current density, and prolonging the service life of the battery monomer.

[0008] In addition, the width of the tab is in a suitable range, so that the tab is less likely to interfere with other structural members of the end cover (such as a pressure relief mechanism, a liquid injection hole, etc.), thereby helping to improve the assembly reliability of the battery monomer.

[0009] In some embodiments, the tab includes a positive tab and a negative tab; a minimum width of the positive tab along the second direction is in a range from 90 mm to 110 mm; and / or a minimum width of the negative tab along the second direction is in a range from 90 mm to 110 mm.

[0010] In this way, the widths of the positive tab and the negative tab are in a proper range, which is beneficial to increase the flow area of the positive tab and the negative tab, thereby improving the energy conversion efficiency of the battery cell. Moreover, the current distribution flowing through the positive tab and the negative tab can be made more uniform, thereby reducing the risk of local overheating caused by current concentration, and thus reducing the possibility of thermal runaway of the battery cell and improving the reliability of the battery cell. In addition, while the energy conversion efficiency of the battery cell is improved, the positive tab and the negative tab are also less likely to interfere with other structural components on the end cover, which is beneficial to further improve the reliability of the battery cell.

[0011] In some embodiments, the end cover is formed with a mounting hole, and the battery cell further includes: an electrode terminal, the electrode terminal being arranged through the mounting hole; and an electrical connecting piece, the electrical connecting piece connecting the electrode terminal and the tab, the electrical connecting piece including a tab connecting portion and an electrode terminal connecting portion, the tab connecting portion connecting the tab, and the electrode terminal connecting portion connecting the electrode terminal; wherein the number of the tab connecting portions is two, and the two tab connecting portions are located on opposite sides of the electrode terminal connecting portion along the first direction.

[0012] In this way, the two tab connecting portions can be electrically connected with the tabs of the two electrode assemblies respectively, thereby realizing the electrical connection of the two electrode assemblies, and further being beneficial to improve the energy density of the battery cell.

[0013] In some embodiments, along the first direction, the two tab connecting portions are spaced apart from each other to form a clearance space.

[0014] In this way, the clearance space can avoid interference with structures such as the liquid injection hole on the end cover, which is beneficial to improve the compactness of the structure of the battery cell.

[0015] In some embodiments, the tab and the tab connecting portion are welded to form a weld mark, and the total cross-sectional area of the weld mark at the tab connecting portion of one electrical connecting piece is in a range from 300 mm 2 to 650 mm 2 .

[0016] The welding mark cross-sectional area of the tab and the tab connecting portion is large, thereby making the connection between the tab and the electrical connecting piece more stable and reliable, and the welding quality better. Moreover, the larger welding mark cross-sectional area makes the contact area between the tab and the electrical connecting piece larger, thereby being able to reduce the contact resistance, improve the energy conversion efficiency of the battery monomer, and further make the voltage and current output by the battery monomer more stable, prolong the endurance time of the battery monomer, and improve the overall performance of the battery monomer. In addition, the larger welding mark cross-sectional area is beneficial to dispersing the stress of the welding part of the tab and the electrical connecting piece, reducing the risk of cracks or breakage of the welding part caused by excessive local stress, and further improving the connection reliability between the tab and the electrical connecting piece.

[0017] In some embodiments, the tab includes a positive electrode tab, the electrode terminal includes a positive electrode terminal, the electrical connecting piece includes a first electrical connecting piece, the first electrical connecting piece connects the positive electrode tab and the positive electrode terminal, the welding mark includes a first welding mark, the positive electrode tab is welded with the tab connecting portion of the first electrical connecting piece to form the first welding mark, and the total cross-sectional area of the first welding mark is in the range of 500 mm 2 to 650 mm 2 .

[0018] Thereby, the positive electrode tab and the first electrical connecting piece can have sufficient contact area, thereby realizing stable electrical connection with low resistance, reducing loss in the process of electrical energy transmission, and improving the charging and discharging efficiency and performance of the battery monomer. In addition, a suitable welding mark cross-sectional area is helpful to form a firm welding point, so that the positive electrode tab and the first electrical connecting piece can withstand certain mechanical stress (such as vibration, impact, etc.) during use of the battery monomer, and are not prone to false welding, welding failure or loose connection, thereby improving the overall reliability and service life of the battery monomer.

[0019] In some embodiments, the number of first welding marks at one tab connecting portion of the first electrical connecting piece is a plurality, and the plurality of first welding marks are arranged spaced apart from each other along the second direction.

[0020] Thereby, the plurality of first welding marks provides a plurality of parallel conduction paths for the current, making the distribution of the current more uniform throughout the connection area, reducing the risk of local overheating, accelerated aging of materials, and local damage of the first electrical connecting piece caused by current concentration, and improving the stability and reliability of the battery monomer during long-term use. Moreover, the plurality of first welding marks disperses the effect of external force on the connecting part, reducing the possibility of stress concentration. When the battery monomer is subjected to mechanical stress such as vibration and impact, the tab connecting portion of the first electrical connecting piece can better withstand these stresses, reducing the possibility of a single welding mark cracking, welding failure, and other failure conditions caused by bearing excessive mechanical load, thereby enhancing the mechanical strength and fatigue resistance of the entire electrical connection structure and prolonging the service life of the battery monomer.

[0021] In some embodiments, the tab includes a negative tab, the electrode terminal includes a negative terminal, the electrical connector includes a second electrical connector, the second electrical connector connects the negative tab and the negative terminal, the weld includes a second weld, the negative tab is welded with a tab connecting portion of the second electrical connector to form the second weld, and a total cross-sectional area of the second weld is in a range from 300 mm 2 to 500 mm 2 .

[0022] Thus, sufficient contact area can be provided between the negative tab and the second electrical connector, so as to realize stable electrical connection with low resistance, reduce loss in the process of electrical energy transmission, and improve the charging and discharging efficiency and performance of the battery monomer. In addition, a suitable cross-sectional area of the weld helps to form a firm welding point, so that the negative tab and the second electrical connector can withstand certain mechanical stress (such as vibration, impact, etc.) during use of the battery monomer, and are less likely to appear in the case of loose welding, welding or loose connection, thereby improving the overall reliability and service life of the battery monomer. In addition, since the material of the negative tab is generally better in electrical conductivity, the requirement for the connection area is relatively low, so a smaller cross-sectional area of the weld can also meet the electrical connection requirements of the negative tab. The cross-sectional area of the second weld is in a suitable range, which can reduce the manufacturing and assembly cost of the battery monomer on the premise of ensuring the connection quality and electrical connection requirements.

[0023] In some embodiments, the number of the second welds at one tab connecting portion of the second electrical connector is a plurality, and the plurality of second welds are arranged spaced apart from each other along the second direction.

[0024] Thus, the plurality of second welds provides a plurality of parallel conduction paths for the current, so that the distribution of the current in the entire connection area is more uniform, reducing the risk of local overheating, accelerated aging of materials and local damage of the second electrical connector caused by current concentration, and improving the stability and reliability of the battery monomer during long-term use. Moreover, the plurality of second welds disperses the effect of external force on the connecting portion, reducing the possibility of stress concentration. When the battery monomer is subjected to mechanical stress such as vibration and impact, the tab connecting portion of the second electrical connector can better withstand these stresses, reducing the possibility of cracking, welding and other failure conditions of a single weld due to bearing excessive mechanical load, thereby enhancing the mechanical strength and fatigue resistance of the entire electrical connection structure and prolonging the service life of the battery monomer.

[0025] In some embodiments, the minimum cross-sectional area of the electrode terminal is in a range from 800 mm 2 to 1100 mm 2 .

[0026] The cross-sectional area of the electrode terminal is in a proper range, so that the resistance is reduced when current passes, and the electron flows more smoothly, thereby improving the transmission efficiency of the current, reducing the loss of electric energy, and further improving the energy conversion efficiency of the battery cell. In addition, the proper cross-sectional area of the electrode terminal can reduce the current density and reduce the generation of Joule heat, thereby reducing the possibility of electrode terminal heating, improving the thermal stability of the battery cell, and improving the reliability of the battery cell.

[0027] The second aspect of the present application provides a battery device, comprising: a box body; and at least one battery cell of the first aspect of the present application, which is contained in the box body.

[0028] The battery device of the present application has high energy conversion efficiency as a whole due to the battery cell with high overcurrent capacity and high energy conversion efficiency provided by the first aspect, thereby improving the endurance of the battery device. In addition, the high energy conversion efficiency of the battery device can provide more effective electric energy output, thereby improving the cost-effectiveness.

[0029] The third aspect of the present application provides a power consumption device, which comprises the battery cell of the first aspect of the present application or the battery device of the second aspect of the present application for providing electric energy.

[0030] The power consumption device of the present application comprises the battery cell with high overcurrent capacity and high energy conversion efficiency provided by the first aspect or the battery device with high overcurrent capacity and high energy conversion efficiency provided by the second aspect. Therefore, it is beneficial to prolong the power supply time of the battery cell or the battery device to the power consumption device, and to provide good power supply to the power consumption device.

[0031] The fourth aspect of the present application provides an energy storage device, which comprises the battery cell of the first aspect of the present application or the battery device of the second aspect of the present application for providing electric energy.

[0032] The energy storage device of the present application comprises the battery cell with high overcurrent capacity and high energy conversion efficiency provided by the first aspect or the battery device with high overcurrent capacity and high energy conversion efficiency provided by the second aspect. Therefore, it is beneficial to prolong the power supply time of the battery cell or the battery device to the energy storage device, and to provide good power supply to the energy storage device.

[0033] Effect of the utility model

[0034] Through the present application, a battery cell with high overcurrent capacity and high energy conversion efficiency, a battery device, a power consumption device, and an energy storage device are provided. BRIEF DESCRIPTION OF DRAWINGS

[0035] Various other advantages and benefits will become apparent to those of ordinary skill in the art upon reading the following detailed description of the preferred embodiments with reference made to the accompanying drawings. The drawings are for purposes of illustration only and are not intended to be limiting in accordance with the present application. Like reference numerals have been used wherever possible throughout the drawings and the following detailed description to refer to similar objects, components, and functions. In the drawings:

[0036] Figure 1 A structural schematic diagram of a vehicle provided for some embodiments of the present application;

[0037] Figure 2 A perspective exploded schematic diagram of a battery device provided for some embodiments of the present application;

[0038] Figure 3 A perspective exploded schematic diagram of a battery cell provided for some embodiments of the present application;

[0039] Figure 4 A partial planar structural schematic diagram of a positive electrode tab, a negative electrode tab, and a separator provided for some embodiments of the present application;

[0040] Figure 5 A bottom planar structural schematic diagram of a tab, an end cap, and an electrical connector provided for some embodiments of the present application Figure 1 ;

[0041] Figure 6 A bottom planar structural schematic diagram of a tab, an end cap, and an electrical connector provided for some embodiments of the present application Figure 2 .

[0042] BRIEF DESCRIPTION OF DRAWINGS

[0043] 1. housing; 11, housing; 11a, opening; 12, end cap; 2, electrode assembly; 21, electrode body; 21a, positive electrode tab; 21b, negative electrode tab; 21c, separator; 22, tab; 221, positive electrode tab; 222, negative electrode tab; 3, pressure relief mechanism; 4, liquid injection hole; 5, electrode terminal; 51, positive electrode terminal; 52, negative electrode terminal; 6, electrical connector; 6a, first electrical connector; 6b, second electrical connector; 61, tab connecting portion; 611, avoidance space; 62, electrode terminal connecting portion; 7, solder print; 71, first solder print; 72, second solder print; 100, battery cell; 200, controller; 300, motor; 400, battery device; 401, box body; 401a, cover body; 401b, bottom plate; 1000, vehicle; L1, length of end cap in second direction; L2, minimum width of tab in second direction. DETAILED DESCRIPTION

[0044] The embodiments of the present application will be described in detail below with reference to the drawings. The following examples are only used to more clearly illustrate the technical scheme of the present application, and therefore only serve as examples, but cannot be used to limit the protection scope of the present application.

[0045] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the present application; the use of the terms "include," "have" and "comprise" and variations thereof herein are meant to encompass the items listed thereafter, but do not exclude additional items.

[0046] In the description of the embodiments of the present application, the technical terms "first", "second", "third" and the like are only used to distinguish different objects, and cannot be understood as indicating or implying relative importance or implicitly indicating the number, specific order or primary and secondary relationship of the technical features indicated. In the description of the embodiments of the present application, the meaning of "a plurality of" is two or more, unless otherwise explicitly and specifically limited.

[0047] Reference herein to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the application. The appearance of the phrase in various places in the specification does not necessarily all refer to the same embodiment, nor is it necessarily independent or alternative embodiments to each other. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0048] In the description of the embodiments of the present application, the term "and / or" is only a description of the association relationship of the associated objects, which means that there can be three relationships, for example, A and / or B, which can represent the three cases of A alone, A and B together, and B alone. In addition, the character " / " in this paper generally represents that the front and rear associated objects are "or" relationship.

[0049] In the description of the embodiments of the present application, the technical terms "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "circumferential" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, which is only for the convenience of describing the embodiments of the present application and simplifying the description, and is not intended to indicate or imply that the indicated device or element must have a particular orientation, be constructed, operated or used in a particular orientation, and therefore cannot be understood as limiting the embodiments of the present application.

[0050] In the description of the embodiments of the present application, unless explicitly defined and limited otherwise, the technical terms "mounting", "connecting", "connecting", "fixing" and the like should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or it can be integrated; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the internal communication of two elements or the interaction relationship between two elements. For those skilled in the art, the specific meaning of the above terms in the embodiments of the present application can be understood according to the specific circumstances.

[0051] In the description of the embodiments of the present application, unless explicitly defined and limited otherwise, the technical term "contact" should be understood broadly, which can be direct contact or contact through an intermediate medium layer, and can be contact between two objects in contact without interaction force, or contact between two objects in contact with interaction force.

[0052] Next, the present application will be described in detail.

[0053] At present, new energy batteries are more and more widely used in life and industry. New energy batteries are not only used in energy storage power supply systems such as hydroelectric, thermal, wind and solar power stations, but also widely used in electric bicycles, electric motorcycles, electric vehicles and other electric vehicles, and aerospace and other fields. With the continuous expansion of the application field of power batteries, the market demand is also increasing.

[0054] The electrode assembly of the battery monomer includes an electrode body and a tab connected to the electrode body. The tab is a metal conductor that leads the positive and negative electrodes out of the electrode body. The tab can conduct current out of the electrode body. As a contact point when the battery monomer is charged and discharged.

[0055] With the continuous progress of science and technology, battery monomers are developing towards larger capacity and larger size, which also poses greater challenges to the overcurrent capacity and energy conversion efficiency of battery monomers. Since the current of the electrode body ultimately flows to the tab, the current density is the largest near the tab. According to Joule's law, heat is generated when current passes through a conductor, and the heat is proportional to the square of the current. Therefore, near the tab, the Joule heat generated is also larger due to the large current density. With the increase of the battery monomer, the problem of uneven distribution of current field and heat of the electrode assembly near the tab of the electrode assembly is more likely to occur, thereby causing the performance of the battery monomer to decline or even directly jump.

[0056] Therefore, the width of the tab in the second direction is in a suitable range, which can increase the current flow area, thereby reducing the electron transmission impedance, and thus is conducive to reducing the energy loss of the battery monomer during charging and discharging, and improving the energy conversion efficiency of the battery monomer.

[0057] Therefore, the width of the tab in the second direction is in a suitable range, which can increase the current flow area, thereby reducing the electron transmission impedance, and thus is conducive to reducing the energy loss of the battery monomer during charging and discharging, and improving the energy conversion efficiency of the battery monomer.

[0058] Furthermore, the width of the tab is in a suitable range, so that the tab can carry a larger current, and the distribution of the current is more uniform, reducing local heat accumulation caused by current concentration, and also enabling the battery monomer to better meet the output demand of high power during high-rate discharge, thereby facilitating stable discharge of the battery monomer, reducing polarization phenomenon caused by excessive current density, and prolonging the service life of the battery monomer.

[0059] In addition, the width of the tab is in a suitable range, so that the tab is less likely to interfere with other structural members of the end cover (such as a pressure relief mechanism, a liquid injection hole, etc.), thereby facilitating improvement of the assembly reliability of the battery monomer.

[0060] The battery provided by the embodiments of the present application can be used in, but is not limited to, an electric device such as an energy storage power supply system, a vehicle, a ship or an aircraft, and an energy storage device such as an energy storage container or an energy storage cabinet.

[0061] The embodiments of the present application provide an electric device including the above-mentioned battery for providing electric energy. The electric device includes, but is not limited to, a mobile phone, a tablet, a notebook computer, an electric toy, an electric tool, an electric vehicle, an electric car, a ship, a spacecraft, etc. The electric toy can include a fixed or mobile electric toy, such as a game console, an electric car toy, an electric ship toy, and an electric plane toy, etc. The spacecraft can include an airplane, a rocket, a space shuttle, a spacecraft, etc.

[0062] In the following embodiments, for the convenience of description, the electric device of an embodiment of the present application is taken as a vehicle 1000 for example.

[0063] Figure 1A structural schematic diagram of a vehicle 1000 is provided for some embodiments of the present application. The vehicle 1000 can be a fuel automobile, a gas automobile, or a new energy automobile, which can be a pure electric automobile, a hybrid automobile, or a range extended automobile, etc. As shown in Figure 1 The vehicle 1000 is internally provided with a battery monomer 100, which can be arranged at the bottom, head, or tail of the vehicle 1000. The battery monomer 100 can be used for power supply of the vehicle 1000, for example, the battery monomer 100 can be used as an operating power source of the vehicle 1000. The vehicle 1000 can further include a controller 200 and a motor 300, the controller 200 is used to control the battery monomer 100 to supply power to the motor 300, for example, for the power demand of starting, navigation, and driving of the vehicle 1000.

[0064] In some embodiments of the present application, the battery monomer 100 can not only be used as an operating power source of the vehicle 1000, but also be used as a driving power source of the vehicle 1000, instead of or partially instead of fuel or natural gas to provide driving power for the vehicle 1000.

[0065] Figure 2 A three-dimensional exploded schematic diagram of a battery device 400 is provided for embodiments of the present application. As shown in Figure 2 The battery device 400 includes a box body 401 and at least one battery monomer 100, and the battery monomer 100 is contained in the box body 401. The box body 401 includes a cover body 401a and a bottom plate 401b, and the cover body 401a is covered above the bottom plate 401b, so as to form a containing area of the battery monomer 100 between the bottom plate 401b and the cover body 401a.

[0066] In the battery device 400, the battery monomer 100 can be multiple, and the multiple battery monomers 100 can be connected in series, in parallel, or in a mixed connection, which means that the multiple battery monomers 100 are connected in series and in parallel. The multiple battery monomers 100 can be directly connected in series, in parallel, or in a mixed connection, and then the whole of the multiple battery monomers 100 is placed in the containing space formed by the bottom plate 401b and the cover body 401a. Of course, the battery monomer 100 can also be that multiple battery monomers 100 are first connected in series, in parallel, or in a mixed connection to form a battery module, and multiple battery modules are connected in series, in parallel, or in a mixed connection to form a whole, and are contained in the containing space formed by the bottom plate 401b and the cover body 401a. The battery device 400 can further include other structures, for example, the battery device 400 can further include a current combing component for realizing the electrical connection between the multiple battery monomers 100.

[0067] Next, some embodiments of the present application are described in detail. Figures 3 to 6

[0068] Figure 3 ​A perspective exploded schematic view of a battery cell is provided for some embodiments of the present application. Figure 4 A partial planar structure schematic view of a positive electrode sheet, a negative electrode sheet and a separator of an electrode body is provided for some embodiments of the present application. Figure 5 A bottom planar structure schematic view of a tab, an end cover and an electrical connector is provided for some embodiments of the present application. Figure 1 Figure 6 A bottom planar structure schematic view of a tab, an end cover and an electrical connector is provided for some embodiments of the present application. Figure 2

[0069] In some embodiments of the present application, a first direction and a second direction are set for the purpose of illustration, and the first direction and the second direction are perpendicular to each other. However, those skilled in the art should understand that the embodiments of the present application are not limited to the case where the three directions are perpendicular to each other. For the purpose of illustration, as shown by the arrows in Figures 3 to 6 , the direction in which the arrow X is located is the first direction, and the direction in which the arrow Y is located is the second direction. In some embodiments, the first direction can also be referred to as the thickness direction of the battery cell, and the second direction can also be referred to as the length direction of the battery cell.

[0070] A first aspect of the present application provides a battery cell 100. As shown in Figure 3 and Figure 4 , the battery cell 100 includes a housing 1 and an electrode assembly 2. The housing 1 includes a shell 11 formed with an opening 11a and an end cover 12 covering the opening 11a. The electrode assembly 2 is located in the housing 1. The electrode assembly 2 includes an electrode body 21 and a tab 22 connected to the electrode body 21, and the electrode body 21 includes a positive electrode sheet 21a, a negative electrode sheet 21b and a separator 21c stacked in a first direction. Wherein, the length L1 of the end cover 12 in the second direction is in the range of 320mm to 480mm. The ratio of the minimum width L2 of the tab 22 in the second direction to the length L1 of the end cover 12 in the second direction is in the range of 0.23 to 0.35. The second direction intersects the first direction.

[0071] The battery cell 100 refers to a basic unit capable of converting chemical energy and electrical energy to each other, which can be used to make a battery device 400, thereby used to power a power consumption device or an energy storage device.

[0072] In the embodiments of the present application, the battery cell 100 can be a secondary battery cell, which refers to a battery cell that can be activated by charging after discharging.

[0073] ​​The battery cell 100 can be a lithium-ion battery cell, a sodium-ion battery cell, a sodium-lithium-ion battery cell, a lithium metal battery cell, a sodium metal battery cell, a lithium-sulfur battery cell, a magnesium-ion battery cell, a nickel-hydrogen battery cell, a nickel-cadmium battery cell, a lead-acid battery cell, etc., and the embodiments of the present application are not limited to this.

[0074] In the embodiment of the present application, the battery cell 100 is a square-shell battery cell. In some other embodiments, the battery cell 100 may also be a battery cell of other shapes, which is not particularly limited in the present application.

[0075] The electrode assembly 2 is a component where electrochemical reactions occur in the battery cell 100, and the electrode assembly 2 includes an electrode body 21. Figure 4 As shown, the electrode body 21 includes a positive electrode sheet 21a, a negative electrode sheet 21b, and a separator 21c. The positive electrode sheet 21a, the negative electrode sheet 21b, and the separator 21c are generally stacked along the thickness direction (first direction) of the battery cell 100. During the charge and discharge process of the battery cell 100, active ions (such as lithium ions) are inserted and removed between the positive electrode sheet 21a and the negative electrode sheet 21b. The separator 21c is provided between the positive electrode sheet 21a and the negative electrode sheet 21b to prevent short circuits between the positive and negative electrode sheets while allowing the active ions to pass through.

[0076] In some embodiments, the positive electrode sheet 21 a may include a positive electrode current collector and a positive electrode active material disposed on at least one surface of the positive electrode current collector.

[0077] As an example, the positive electrode current collector has two surfaces facing each other in its thickness direction, and the positive electrode active material is provided on either or both of the two facing surfaces of the positive electrode current collector.

[0078] As examples, the positive electrode current collector can be made of metal foil, conductive polymer material, carbon material, or composite current collector. For example, the metal foil can be made of pure metals, alloys, or surface-treated metals, including but not limited to stainless steel, copper, aluminum, nickel, titanium, or silver. A composite current collector can include a polymer base layer and a metal layer. The composite current collector can be formed by forming a metal material (such as aluminum, aluminum alloys, nickel, nickel alloys, titanium, titanium alloys, silver, and silver alloys) onto a polymer substrate (such as polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0079] As an example, the positive electrode active material may include at least one of the following materials: lithium-containing phosphates, lithium transition metal oxides, and their respective modified compounds. However, the present application is not limited to these materials, and other traditional materials that can be used as battery positive electrode active materials may also be used. These positive electrode active materials may be used alone or in combination of two or more. Examples of lithium-containing phosphates may include, but are not limited to, at least one of lithium iron phosphate (such as LiFePO4 (also referred to as LFP)), a composite material of lithium iron phosphate and carbon, lithium manganese phosphate (such as LiMnPO4), a composite material of lithium manganese phosphate and carbon, lithium iron manganese phosphate, and a composite material of lithium iron manganese phosphate and carbon. Examples of lithium transition metal oxides may include, but are not limited to, lithium cobalt oxide (such as LiCoO2), lithium nickel oxide (such as LiNiO2), lithium manganese oxide (such as LiMnO2, LiMn2O4), lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, lithium nickel cobalt manganese oxide (such as LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2 (also referred to as NCM 333 )、LiNi 0.5 Co 0.2 Mn 0.3 O2 (also referred to as NCM 523 )、LiNi 0.5 Co 0.25 Mn 0.25 O2 (also referred to as NCM 211 )、LiNi 0.6 Co 0.2 Mn 0.2 O2 (also referred to as NCM 622 )、LiNi 0.8 Co 0.1 Mn 0.1 O2 (also referred to as NCM 811 ), lithium nickel cobalt aluminum oxide (such as LiNi 0.8 Co 0.15 Al 0.05 O2) and at least one of its modified compounds. Modified compounds refer to substances obtained by modifying the above substances through methods such as doping or coating.

[0080] In some embodiments, the positive electrode sheet 21a may be made of metal foam. The metal foam may be nickel foam, copper foam, aluminum foam, or alloy foam, among others. When the metal foam is used as the positive electrode, the surface of the metal foam may or may not be provided with a positive electrode active material. As an example, a lithium source material, potassium metal, or sodium metal may be filled and / or deposited within the metal foam, where the lithium source material is lithium metal and / or a lithium-rich material.

[0081] In some embodiments, the negative electrode sheet 21b can include a negative electrode current collector.

[0082] As an example, the negative electrode current collector can employ a metal foil, a conductive polymer material, a carbon material, or a composite current collector. For example, as the metal foil, a pure metal, an alloy, a surface-treated metal, including but not limited to stainless steel, copper, aluminum, nickel, titanium, or silver, and the like can be employed. The composite current collector can include a polymer material base layer and a metal layer. The composite current collector can be formed by forming a metal material (copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver, and silver alloy, and the like) on a polymer material base material (such as a base material of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, and the like).

[0083] As an example, the negative electrode sheet can include a negative electrode current collector and a negative electrode active material disposed on at least one surface of the negative electrode current collector.

[0084] As an example, the negative electrode current collector has two surfaces opposite in the thickness direction thereof, and the negative electrode active material is disposed on either one or both of the two opposite surfaces of the negative electrode current collector.

[0085] As an example, the negative electrode active material can employ a negative electrode active material for a battery cell known in the art. As an example, the negative electrode active material can include at least one of artificial graphite, natural graphite, soft carbon, hard carbon, a silicon-based material, a tin-based material, lithium titanate, and the like. The silicon-based material can be selected from at least one of elemental silicon, a silicon oxide compound, a silicon-carbon composite, a silicon-nitrogen composite, and a silicon alloy. The tin-based material can be selected from at least one of elemental tin, a tin oxide compound, and a tin alloy. However, the present application is not limited to these materials, and other conventional materials that can be used as a negative electrode active material for a battery cell can also be used. These negative electrode active materials can be used alone or in combination of two or more.

[0086] In some embodiments, the negative electrode can employ a foamed metal. The foamed metal can be foamed nickel, foamed copper, foamed aluminum, foamed alloy, and the like. When the foamed metal is used as the negative electrode sheet, the surface of the foamed metal can not be provided with a negative electrode active material, or can be provided with a negative electrode active material.

[0087] As an example, the negative electrode active material can be filled and / or deposited in the negative electrode current collector.

[0088] In some embodiments, the material of the positive electrode current collector can be aluminum, and the material of the negative electrode current collector can be copper.

[0089] In some embodiments, the separator 21c is a separator film. The present application does not have a particular limitation on the type of the separator film, and any known porous structure separator film having good chemical stability and mechanical stability can be used.

[0090] As an example, the primary material of the separator can be selected from at least one of glass fiber, non-woven fabric, polyethylene, polypropylene, polyvinylidene fluoride, and ceramic. The separator can be a single-layer film or a multi-layer composite film, without particular limitation. When the separator is a multi-layer composite film, the materials of each layer can be the same or different, without particular limitation. The separator can be a separate component located between the positive and negative electrodes, or it can be attached to the surfaces of the positive and negative electrodes. The surface of the separator can also be coated with an inorganic particle coating, an organic particle coating, or an organic / inorganic composite coating.

[0091] In some embodiments, the separator 21c is a solid electrolyte. The solid electrolyte is disposed between the positive electrode and the negative electrode, and serves to transport ions and isolate the positive and negative electrodes.

[0092] In some embodiments, the battery cell 100 further includes an electrolyte, which acts as a conductor of ions between the positive and negative electrodes. This application does not specifically limit the type of electrolyte, and the electrolyte may be selected based on needs. The electrolyte may be liquid, gel, or solid.

[0093] The liquid electrolyte includes an electrolyte salt and a solvent.

[0094] In some embodiments, the electrolyte salt may be selected from at least one of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, lithium bis(fluorosulfonyl)imide, lithium bis(trifluoromethanesulfonyl)imide, lithium trifluoromethanesulfonate, lithium difluorophosphate, lithium difluorooxalatoborate, lithium dioxalatoborate, lithium difluorodioxalatophosphate, and lithium tetrafluorooxalatophosphate.

[0095] In some embodiments, the solvent can be selected from at least one of ethylene carbonate, propylene carbonate, ethyl methyl carbonate, diethyl carbonate, dimethyl carbonate, dipropyl carbonate, methylpropyl carbonate, ethylpropyl carbonate, butylene carbonate, fluoroethylene carbonate, methyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate, ethyl butyrate, 1,4-butyrolactone, cyclopentane, dimethyl sulfone, methyl ethyl sulfone and diethyl sulfone. The solvent can also be an ether solvent. Ether solvents can include one or more of ethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, 1,3-dioxolane, tetrahydrofuran, methyltetrahydrofuran, diphenyl ether and crown ether.

[0096] The electrode body 21 of the electrode assembly 2 may be a wound structure, a laminated structure, or a mixed structure of a wound structure and a laminated structure.

[0097] In some embodiments, the electrode body 21 is a wound structure in which the positive electrode sheet 21a and the negative electrode sheet 21b are wound.

[0098] In some embodiments, the electrode body 21 is a laminated structure.

[0099] As an example, a plurality of positive electrode sheets 21a and a plurality of negative electrode sheets 21b are alternately laminated.

[0100] As an example, a plurality of positive electrode sheets 21a are provided, and the negative electrode sheet 21b is folded to form a plurality of folded sections laminated.

[0101] As an example, a plurality of positive electrode sheets 21a and a plurality of negative electrode sheets 21b are alternately laminated.

[0102] As an example, a plurality of positive electrode sheets 21a and a plurality of negative electrode sheets 21b are alternately laminated.

[0103] As an example, a plurality of positive electrode sheets 21a and a plurality of negative electrode sheets 21b are alternately laminated.

[0104] As shown in FIG. 1, the battery cell 100 includes an outer shell 1, which is an external protective housing of the battery cell 100, and has an accommodation cavity formed therein for accommodating an electrode assembly 2 and an electrolyte, etc. Figure 3

[0105] In some embodiments, the outer shell 1 can be a sealed structure or a non-sealed structure. As an example, when the outer shell 1 is a sealed structure, the outer shell 1 serves to protect the electrode assembly 2 accommodated therein. The outer shell 1 and the electrode assembly 2 can further include a sealing bag for packaging the electrode assembly 2 and the electrolyte. Specifically, the sealing bag can be a bag-shaped insulating member or an aluminum-plastic film.

[0106] In some embodiments, the outer shell 1 includes an end cap 12 and a shell body 11. The shell body 11 is provided with an opening 11a. The end cap 12 closes the opening 11a to form a closed space for accommodating the electrode assembly 2 and the electrolyte, etc. The shell body 11 can be provided with one or more openings 11a. The number of end caps 12 can also be one or more.

[0107] In some embodiments, as shown in FIG. 2, the length L1 of the end cap 12 in the second direction is in the range of 320 mm to 480 mm. Figure 5

[0108] ​​Exemplarily, the length L1 of the end cover 12 along the second direction can be 320 mm, 330 mm, 340 mm, 350 mm, 360 mm, 370 mm, 380 mm, 390 mm, 400 mm, 410 mm, 420 mm, 430 mm, 440 mm, 450 mm, 460 mm, 470 mm, or 480 mm, etc.

[0109] The length L1 of the end cover 12 along the second direction is large, thereby the length dimension of the opening 11a covered by the end cover 12 is also large, which corresponds to a larger internal space of the casing 11 of the battery monomer 100, so that the size of the electrode body 21 accommodated in the casing 1 can be made larger, and further more active material can be accommodated in the casing 1, or a larger electrode body 21 can be used, which significantly improves the energy density of the battery monomer 100.

[0110] The electrode assembly 2 further comprises a tab 22 connected with the electrode body 21. The tab 22 can conduct current from the electrode body 21. The tab 22 serves as a core current passage connecting the electrode body 21 inside the battery monomer 100 with the outside end cover 12 or electrode terminal, and the width of the tab 22 directly determines the cross-sectional area of the current passage.

[0111] In some embodiments, as shown in Figs. 1 and 2, the minimum width L2 of the tab 22 along the second direction is less than the length L1 of the end cover 12 along the second direction. Figure 5 and Figure 6 As shown in Figs. 1 and 2, the ratio of the minimum width L2 of the tab 22 along the second direction to the length L1 of the end cover 12 along the second direction is in the range of 0.23 to 0.35. That is, L2 / L1 = 0.23~0.35.

[0112] Exemplarily, the ratio of the minimum width L2 of the tab 22 along the second direction to the length of the end cover 12 along the second direction can be 0.23, 0.24, 0.25, 0.26, 0.27, 0.28, 0.29, 0.30, 0.31, 0.32, 0.33, 0.34, or 0.35, etc.

[0113] Thus, the width of the tab 22 along the second direction can be in a suitable range, so as to increase the current flow area, reduce the electron transmission impedance, and further facilitate reducing the energy loss of the battery monomer 100 during charging and discharging, and improving the energy conversion efficiency of the battery monomer 100.

[0114] Moreover, the width of the tab 22 is in a suitable range, so that the tab 22 can carry larger current, and the distribution of the current is more uniform, which reduces the local heat accumulation caused by current concentration, and also enables the battery monomer 100 to better meet the output demand of large power during high-rate discharging, thereby facilitating the battery monomer 100 to stably discharge, reducing the polarization phenomenon caused by excessive current density, and prolonging the service life of the battery monomer 100.

[0115] In addition, the tab 22 is also a key thermal bridge for transferring heat generated inside the battery monomer 100 to the end cover 12. The width of the tab 22 is increased, which can provide a larger heat conduction cross-sectional area, so that the heat inside the battery monomer 100 can be transferred to the end cover 12 more quickly and uniformly, and then to the outside, thereby improving the heat management capability of the battery monomer 100 and delaying the aging of the battery monomer 100.

[0116] Furthermore, the width of the tab 22 is within a suitable range, so that the tab 22 is not prone to interference with other structural members of the end cover 12 (such as the pressure relief mechanism 3, the liquid injection hole 4, etc.), thereby facilitating improvement of the assembly reliability of the battery monomer 100. Exemplarily, the pressure relief mechanism 3 can be a pressure relief valve.

[0117] Generally, along the extension direction of the tab 22, the width of the root of the tab 22 along the second direction is greater than the width of the top of the tab 22 along the second direction. That is, the tab 22 is generally trapezoidal. The root of the tab 22 is the side connected with the electrode body 21, and the top of the tab 22 is the side for connecting with the electrical connecting member.

[0118] In the embodiments of the present application, the minimum width of the tab 22 along the second direction can be understood as the width of the top of the tab 22. That is, along the extension direction of the tab 22, the width of the side farthest from the electrode body 21 of the tab 22.

[0119] In some embodiments of the present application, the tab 22 includes a positive tab 221 and a negative tab 222. The minimum width of the positive tab 221 along the second direction is within the range of 90 mm to 110 mm, and / or the minimum width of the negative tab 222 along the second direction is within the range of 90 mm to 110 mm.

[0120] The minimum width of the positive tab 221 and the negative tab 222 along the second direction can be the same or different.

[0121] Exemplarily, the minimum width of the positive tab 221 along the second direction can be 90 mm, 92 mm, 94 mm, 96 mm, 98 mm, 100 mm, 102 mm, 104 mm, 106 mm, 108 mm, or 110 mm, etc. The minimum width of the negative tab 222 along the second direction can be 90 mm, 92 mm, 94 mm, 96 mm, 98 mm, 100 mm, 102 mm, 104 mm, 106 mm, 108 mm, or 110 mm, etc.

[0122] Therefore, the width of the positive tab 221 and the negative tab 222 can be within a suitable range, thereby facilitating improvement of the overcurrent area of the positive tab 221 and the negative tab 222 and improvement of the energy conversion efficiency of the battery monomer 100.

[0123] Moreover, the width of the positive and negative tabs 221 and 222 is within a suitable range, which can also make the current distribution on the positive and negative tabs 221 and 222 more uniform, reduce the risk of local overheating due to current concentration, and thus reduce the possibility of thermal runaway of the battery cell 100 and improve the reliability of the battery cell 100.

[0124] In addition, while the energy conversion efficiency of the battery cell 100 is improved, the width of the positive and negative tabs 221 and 222 is not too large, so it is not easy to interfere with other structural parts on the end cover 12, which is conducive to further improving the reliability of the battery cell 100.

[0125] In some embodiments of the present application, as shown in Figure 5 and Figure 6 The end cover 12 is formed with a mounting hole. The battery cell 100 further includes an electrode terminal 5 and an electrical connecting piece 6. The electrode terminal 5 is threaded through the mounting hole. The electrical connecting piece 6 connects the electrode terminal 5 and the tab 22. The electrical connecting piece 6 includes a tab connecting portion 61 and an electrode terminal connecting portion 62. The tab connecting portion 61 connects the tab 22. The electrode terminal connecting portion 62 connects the electrode terminal 5. Among them, the number of tab connecting portions 61 is two, and the two tab connecting portions 61 are located on the opposite sides of the electrode terminal connecting portion 62 along the first direction.

[0126] The electrode terminal 5 is threaded through the mounting hole of the end cover 12, and part of it is exposed outside the housing 1 through the mounting hole, and part of it is located inside the housing 1. The electrode terminal 5 is used to directly or indirectly electrically connect with the tab 22 of the electrode assembly 2 to output the electrical energy of the electrode body 21 of the electrode assembly 2.

[0127] Exemplarily, the number of electrode terminals 5 can be only one, which is connected with one of the positive and negative tabs 221 and 222, and the other of the positive and negative tabs 221 and 222 is connected with the housing 1. The number of electrode terminals 5 can also be two, and the two electrode terminals 5 are respectively connected with the positive and negative tabs 221 and 222.

[0128] In the embodiments of the present application, the electrode terminal 5 includes a positive electrode terminal 51 and a negative electrode terminal 52, the positive electrode terminal 51 is connected with the positive electrode tab 221, and the negative electrode terminal 52 is connected with the negative electrode tab 222. Therefore, the end cover 12 of the shell 1 is correspondingly formed with two mounting holes for mounting the positive electrode terminal 51 and the negative electrode terminal 52, respectively. It should be understood by those skilled in the art that in some other embodiments, the number of the electrode terminals 5 can also be more (more than two). When the number of the electrode terminals 5 is more, the plurality of electrode terminals 5 can be mounted on the same wall surface of the shell 1, or can be mounted on different wall surfaces of the shell 1. When the plurality of electrode terminals 5 are mounted on different wall surfaces of the shell 1, respectively, each wall surface on which an electrode terminal 5 is mounted can be configured as the end cover 12.

[0129] Exemplarily, the electrode terminal 5 can be a pole, for example, and the electrode terminal 5 can be made of a conductive material to realize the conductive function of the electrode terminal 5.

[0130] In the embodiments of the present application, the electrode terminal 5 is electrically connected with the electrode tab 22 through the electrical connector 6. The electrical connector 6 can also be referred to as a adapter.

[0131] The electrical connector 6 includes a tab connecting portion 61 and an electrode terminal connecting portion 62. The electrode tab 22 is connected with the tab connecting portion 61. The electrode terminal 5 is connected with the electrode terminal connecting portion 62, so that the electrical connection between the electrode tab 22 and the electrode terminal 5 can be realized through the electrical connector 6.

[0132] Exemplarily, the electrode tab 22 and the electrode terminal 5 can be welded with the tab connecting portion 61 and the electrode terminal connecting portion 62 of the electrical connector 6, respectively, by laser welding.

[0133] Exemplarily, the electrode tab 22 and the electrode terminal 5 can be welded with the tab connecting portion 61 and the electrode terminal connecting portion 62 of the electrical connector 6, respectively, by ultrasonic welding.

[0134] The embodiments of the present application do not specifically limit the connection manner of the electrode tab 22, the electrode terminal 5 and the electrical connector 6.

[0135] Exemplarily, the electrical connector 6 can be a one-piece structure.

[0136] Exemplarily, the electrical connector 6 can be a split structure and then assembled together, that is, the tab connecting portion 61 and the electrode terminal connecting portion 62 can be a split structure and then spliced and assembled together.

[0137] In some embodiments, a fuse portion can be arranged between the tab connecting portion 61 and the electrode terminal connecting portion 62. That is, a thinned region and / or a fuse hole, etc. is arranged at the connection between the tab connecting portion 61 and the electrode terminal connecting portion 62. In this way, when the current exceeds the rated value, that is, when the current is too large, the fuse portion can be fused, thereby disconnecting the connection between the tab connecting portion 61 and the electrode terminal connecting portion 62, thereby cutting off the electrical connection between the tab 22 and the electrode terminal 5, reducing the possibility of short circuit of the battery monomer 100, and improving the reliability of the battery monomer 100.

[0138] As shown in Figure 3 , Figure 5 and Figure 6 , the electrical connecting piece 6 includes two tab connecting portions 61. The two tab connecting portions 61 can be electrically connected with the tabs 22 of the two electrode assemblies 2 respectively, thereby realizing the electrical connection of the two electrode assemblies 2, and further facilitating the improvement of the energy density of the battery monomer 100.

[0139] Moreover, since the tab connecting portion 61 is located on the opposite sides of the electrode terminal connecting portion 62 along the first direction, the length of the tab connecting portion 61 along the second direction can not be limited by the electrode terminal connecting portion 62, that is, the length of the tab connecting portion 61 along the second direction can be as long as possible without affecting other structural members of the end cover 12, thereby ensuring that the tab connecting portion 61 has sufficient length to electrically connect with the tab 22 which has a large width, and facilitating the improvement of the connection stability of the tab 22 and the electrical connecting piece 6.

[0140] Of course, those skilled in the art should understand that in some embodiments, the tab connecting portion 61 can also be arranged only on one side of the electrode terminal connecting portion 62 along the first direction.

[0141] In some embodiments of the present application, as shown in Figure 5 and Figure 6 , along the first direction, the two tab connecting portions 61 are spaced apart to form an avoiding space 611.

[0142] The two tab connecting portions 61 are arranged spaced apart from each other along the first direction, and the space between the two tab connecting portions 61 is not completely occupied by the electrode terminal connecting portion 62, thereby enabling a certain avoiding space 611 to be formed between the two tab connecting portions 61. The avoiding space 611 can play an avoiding role for other structural members (such as the liquid injection hole 4, the pressure relief mechanism 3, etc.) on the end cover 12, thereby enabling the length of the tab connecting portion 61 to be as long as possible while improving the structural compactness of the battery monomer 100.

[0143] In some embodiments of the present application, the tab 22 and the tab connecting portion 61 are welded to form a weld 7. The total cross-sectional area of the weld 7 at the tab connecting portion 61 of one electrical connecting piece 6 is 300 mm2 from 300mm 2 to 650mm

[0144] Exemplarily, the total cross-sectional area of the welding marks 7 at the tab connecting portion 61 of one electrical connecting piece 6 can be 300mm 2 , 350mm 2 , 400mm 2 , 450mm 2 , 500mm 2 , 550mm 2 , 600mm 2 or 650mm 2 , etc.

[0145] The welding mark cross-sectional area of the tab 22 and the tab connecting portion 61 is large, thereby making the connection between the tab 22 and the electrical connecting piece 6 more stable and reliable, and the welding quality better.

[0146] Moreover, the larger welding mark 7 cross-sectional area makes the contact area between the tab 22 and the electrical connecting piece 6 larger, thereby being able to reduce the contact resistance, improve the energy conversion efficiency of the battery monomer 100, and further make the voltage and current output by the battery monomer 100 more stable, prolong the endurance time of the battery monomer 100, and improve the overall performance of the battery monomer 100.

[0147] In addition, the larger welding mark 7 cross-sectional area is beneficial to dispersing the stress of the welding part of the tab 22 and the electrical connecting piece 6, reducing the risk of cracks or fractures at the welding position caused by excessive local stress, and further improving the connection reliability between the tab 22 and the electrical connecting piece 6.

[0148] Those skilled in the art should understand that the total cross-sectional area of the welding mark 7 refers to the total cross-sectional area of the welding marks 7 at all tab connecting portions 61 of one electrical connecting piece 6. That is, when the electrical connecting piece 6 only includes one tab connecting portion 61, the cross-sectional area of the welding mark 7 is the sum of the cross-sectional areas of all welding marks 7 at the one tab connecting portion 61. When the electrical connecting piece 6 includes two tab connecting portions 61, the cross-sectional area of the welding mark 7 is the sum of the cross-sectional areas of all welding marks 7 at the two tab connecting portions 61. If the number of welding marks 7 at the tab connecting portion 61 of the electrical connecting piece 6 is multiple, the cross-sectional area of the welding mark 7 is the sum of the cross-sectional areas of the multiple welding marks 7 of each tab connecting portion 61 of one electrical connecting piece 6.

[0149] In some embodiments, as shown in Figure 5 and Figure 6 , in the projection plane perpendicular to the height direction of the battery monomer 100, the cross section of the welding mark 7 is rectangular, and thus the cross-sectional area of the welding mark 7 is the length of the welding mark 7 along the first direction multiplied by the width of the welding mark 7 along the first direction.

[0150] In some other embodiments, the cross section of the weld 7 can also be in any other suitable shape.

[0151] The embodiments of the present application do not specifically limit the number and shape of the weld 7, as long as the cross-sectional area of the weld 7 is within the above suitable range.

[0152] In some embodiments of the present application, the tab 22 includes a positive tab 221. The electrode terminal 5 includes a positive terminal 51. The electrical connection 6 includes a first electrical connection 6a connecting the positive tab 221 and the positive terminal 51. The weld 7 includes a first weld 71, the positive tab 221 is welded with the tab connecting portion 61 of the first electrical connection 6a to form the first weld 71, and the total cross-sectional area of the first weld 71 is within the range of 500 mm 2 to 650 mm 2 .

[0153] For example, the total cross-sectional area of the first weld 71 can be 500 mm 2 , 520 mm 2 , 540 mm 2 , 550 mm 2 , 560 mm 2 , 580 mm 2 , 600 mm 2 , 620 mm 2 , 640 mm 2 or 650 mm 2 , etc.

[0154] In this way, the positive tab 221 and the first electrical connection 6a can have sufficient contact area, so as to realize stable electrical connection with low resistance, reduce loss in the process of electrical energy transmission, and improve the energy conversion efficiency, charging and discharging efficiency and performance of the battery monomer 100.

[0155] In addition, the suitable weld cross-sectional area helps to form a firm weld, so that the positive tab 221 and the first electrical connection 6a can withstand certain mechanical stress (such as vibration, impact, etc.) during use of the battery monomer 100, and are not prone to false welding, welding off or loose connection, thereby improving the overall reliability and service life of the battery monomer 100.

[0156] In some embodiments of the present application, the number of the first weld 71 at one tab connecting portion 61 of the first electrical connection 6a is multiple, and the multiple first welds 71 are arranged apart from each other along the second direction.

[0157] Thus, the plurality of first welds 71 provides a plurality of parallel conduction paths for the current, so that the distribution of the current is more uniform throughout the connection area, reducing the risk of local overheating, accelerated aging of the material and local damage of the first electrical connection 6a caused by current concentration, and improving the stability and reliability of the battery cell 100 during long-term use.

[0158] Furthermore, the plurality of first welds 71 disperses the effect of external forces on the connection site of the positive tab 221 and the first electrical connection 6a, reducing the possibility of stress concentration. When the battery cell 100 is subjected to mechanical stress such as vibration and impact, the tab connection part 61 of the first electrical connection 6a can better withstand these stresses, reducing the possibility of a single weld appearing cracks, delamination and other failure conditions due to bearing excessive mechanical load, thereby enhancing the mechanical strength and fatigue resistance of the entire electrical connection structure, and prolonging the service life of the battery cell 100.

[0159] Exemplarily, as shown in Figure 6 , the first electrical connection 6a includes two tab connection parts 61, and the number of first welds 71 at the two tab connection parts 61 is two. The total cross-sectional area of the first welds 71 is the sum of the cross-sectional areas of the four first welds 71.

[0160] In some other embodiments, the first electrical connection 6a can also include only one tab connection part 61 or more (more than two) first welds 71 at one tab connection part 61. The number of first welds 71 at the two tab connection parts 61 can be the same or different. The number of first welds 71 is not specifically limited in the embodiments of the application, as long as the total cross-sectional area of the plurality of first welds 71 at each tab connection part 61 of one first electrical connection 6a is within the above-mentioned appropriate range.

[0161] In addition, the positions of the plurality of first welds 71 at one tab connection part 61 can also be reasonably set so that when the positive tab 221 is welded with the tab connection part 61, the positive tab 221 is not easy to interfere with the electrode terminal connection part 62 while ensuring the connection reliability of the positive tab 221, thereby improving the connection reliability and stability of the positive terminal 51 and the first electrical connection 6a.

[0162] In some embodiments of the application, the tab 22 includes a negative tab 222. The electrode terminal 5 includes a negative terminal 52. The electrical connection 6 includes a second electrical connection 6b connecting the negative tab 222 and the negative terminal 52. The weld 7 includes a second weld 72, and the negative tab 222 is welded with the tab connection part 61 of the second electrical connection 6b to form the second weld 72. The total cross-sectional area of the second weld 72 is in the range of 300 mm 2 to 500 mm 2 .

[0163] Exemplarily, the total cross-sectional area of the second welding bead 72 can be 300mm 2 , 320mm 2 , 340mm 2 , 350mm 2 , 360mm 2 , 380mm 2 , 400mm 2 , 420mm 2 , 440mm 2 , 450mm 2 , 460mm 2 , 480mm 2 or 500mm 2 .

[0164] Thus, sufficient contact area can be provided between the negative tab 222 and the second electrical connecting member 6b, so as to realize stable electrical connection with low resistance, reduce loss in the process of electrical energy transmission, and improve the energy conversion efficiency, charging and discharging efficiency and performance of the battery monomer 100.

[0165] In addition, the appropriate cross-sectional area of the welding bead helps to form a firm welding point, so that the negative tab 222 and the second electrical connecting member 6b can withstand certain mechanical stress (such as vibration, impact, etc.) during use of the battery monomer 100, and are not prone to false welding, welding off or loose connection, thereby improving the overall reliability and service life of the battery monomer 100.

[0166] In the embodiments of the present application, the total cross-sectional area of the second welding bead 72 is smaller than that of the first welding bead 71. This is because the material of the negative tab 222 is usually better in electrical conductivity, so the requirement for the connection area is relatively low, and therefore a smaller cross-sectional area of the welding bead can also meet the electrical connection requirements of the negative tab 222. The total cross-sectional area of the second welding bead 72 is within an appropriate range, which can reduce the manufacturing and assembly cost of the battery monomer 100 while ensuring the connection quality and electrical connection requirements.

[0167] Of course, those skilled in the art should understand that in some embodiments, the total cross-sectional area of the second welding bead 72 can also be equal to that of the first welding bead 71.

[0168] In some embodiments of the present application, the number of the second welding bead 72 at one tab connecting portion of the second electrical connecting member 6b is multiple, and the multiple second welding beads 72 are arranged spaced apart from each other along the second direction.

[0169] As a result, multiple second weld marks 72 provide multiple parallel conduction paths for current, making the current more evenly distributed in the entire connection area, reducing the risks of local overheating, accelerated material aging, and local damage to the second electrical connector 6b caused by current concentration, and improving the stability and reliability of the battery cell 100 during long-term use.

[0170] Furthermore, the multiple second weld marks 72 disperse the effects of external forces on the connection between the negative electrode tab 222 and the second electrical connector 6b, reducing the likelihood of stress concentration. When the battery cell 100 is subjected to mechanical stresses such as vibration and impact, the tab connection portion 61 of the second electrical connector 6b is better able to withstand these stresses, reducing the likelihood of individual weld marks failing due to excessive mechanical loads, such as cracking or desoldering. This enhances the mechanical strength and fatigue resistance of the entire electrical connection structure, extending the service life of the battery cell 100.

[0171] For example, Figure 6 As shown, the second electrical connector 6b includes two tab connection portions 61 , and there are two second weld marks 72 at each of the tab connection portions 61 . The total cross-sectional area of ​​the second weld marks 72 is the sum of the cross-sectional areas of the four second weld marks 72 .

[0172] In some other embodiments, the second electrical connector 6b may include only one tab connection portion 61, or one tab connection portion 61 may include multiple (two or more) second weld marks 72. The number of second weld marks 72 on the two tab connection portions 61 may be the same or different. This embodiment of the present application does not specifically limit the number of second weld marks 72, as long as the total cross-sectional area of ​​the multiple second weld marks 72 on each tab connection portion 61 of a second electrical connector 6b is within the above-mentioned appropriate range.

[0173] In addition, by reasonably arranging the positions of multiple second weld marks 72 at a tab connection portion 61, when the negative tab 222 is welded to the tab connection portion 61, while ensuring the connection reliability of the negative tab 222, it is not easy to interfere with the electrode terminal connection portion 62, thereby improving the connection reliability and stability between the negative terminal 52 and the second electrical connector 6b.

[0174] In some embodiments of the present application, the minimum cross-sectional area of ​​the electrode terminal 5 is 800 mm 2 Up to 1100mm 2 range.

[0175] For example, the minimum cross-sectional area of ​​the electrode terminal 5 may be 800 mm 2 , 850mm 2 , 900mm 2 , 950mm2 1000mm 2 1050mm 2 1100mm 2 etc.

[0176] The cross-sectional area of the electrode terminal 5 is in a suitable range, so that the resistance is reduced when current passes, and the flow of electrons is smoother, thereby improving the transmission efficiency of the current, reducing the loss of electric energy, and further improving the energy conversion efficiency of the battery monomer 100.

[0177] In addition, the suitable cross-sectional area of the electrode terminal 5 can reduce the current density and reduce the generation of Joule heat, thereby reducing the possibility of heating of the electrode terminal 5, improving the thermal stability of the battery monomer 100, and improving the reliability of the battery monomer 100.

[0178] In the embodiments of the present application, the minimum cross-sectional area of the positive electrode terminal 51 and the minimum cross-sectional area of the negative electrode terminal 52 can be in the range of 800mm 2 to 1100mm 2 The minimum cross-sectional area of the positive electrode terminal 51 and the minimum cross-sectional area of the negative electrode terminal 52 can be the same or different.

[0179] The second aspect of the present application provides a battery device, which comprises a box body 401 and at least one battery monomer 100 of the first aspect of the present application. The battery monomer 100 is contained in the box body 401.

[0180] The battery device of the present application has high energy conversion efficiency due to the inclusion of the battery monomer 100 with high overcurrent capacity and high energy conversion efficiency provided by the first aspect, so that the overall energy conversion efficiency of the battery device is high, thereby improving the endurance of the battery device.

[0181] In addition, the battery device has high energy conversion efficiency, which can provide more effective electric energy output, thereby improving the cost-effectiveness.

[0182] The third aspect of the present application provides a power consumption device, which comprises the battery monomer 100 of the first aspect of the present application or the battery device of the second aspect of the present application for providing electric energy.

[0183] The power consumption device of the present application includes the battery monomer 100 with high overcurrent capacity and high energy conversion efficiency provided by the first aspect or the battery device with high overcurrent capacity and high energy conversion efficiency provided by the second aspect. Therefore, it is beneficial to prolong the power supply time of the battery monomer 100 or the battery device to the power consumption device, and to provide good power supply to the power consumption device.

[0184] The fourth aspect of the present application provides an energy storage device, the energy storage device comprising the battery cell 100 of the first aspect of the present application or the battery device of the second aspect of the present application.

[0185] The energy storage device of the present application comprises the battery cell 100 of the first aspect or the battery device of the second aspect, which has high overcurrent capacity and high energy conversion efficiency. Therefore, the power supply time of the battery cell 100 or the battery device to the energy storage device is prolonged, and the energy storage device is well powered.

[0186] Hereinafter, specific examples of some embodiments of the present application will be described with reference to the accompanying drawings.

[0187] As a specific example, the cell (battery cell 100) comprises a top cover (end cover 12), a pole (electrode terminal 5), a tab 22 and a jumper (electrical connector 6). The width of the top cover (the length L1 of the end cover in the second direction) is 320-480mm. The tab 22 comprises a positive tab 221 and a negative tab 222. The top width of the positive tab (the minimum width of the positive tab in the second direction) is 90-110mm. The ratio of the top width of the positive tab to the width of the top cover is in the range of 0.23-0.35. The top width of the negative tab (the minimum width of the negative tab in the second direction) is 90-110mm. The ratio of the top width of the negative tab to the width of the top cover is in the range of 0.23-0.35. The total area of the welding marks of the positive tab and the jumper (the total cross-sectional area of the first welding mark 71) is 500-650mm 2 . The total area of the welding marks of the negative tab and the jumper (the total cross-sectional area of the second welding mark 72) is 300-500mm 2 .

[0188] The wide tab design can increase the overcurrent area and reduce the electron transmission impedance. On the other hand, the widening of the tab can improve the current density distribution, make the current distribution more uniform, reduce the local heat accumulation caused by current concentration, and avoid the risk of thermal runaway. The width of the tab is in a suitable range, which is not easy to interfere with other structures (explosion-proof valve, liquid injection hole, etc.) on the top cover, so as not to affect the production and function of the cell.

[0189] In addition, the larger the welding area of the tab and the jumper, the larger the overcurrent area and the lower the electron transmission impedance, which is beneficial to the improvement of energy efficiency. However, the size of the welding mark is limited by the size of the tab and the jumper, so it is necessary to consider both performance and manufacturability in a suitable range.

[0190] One of the tabs and the welding mark of the adapter plate can be a large welding mark, or two small welding marks. In the case of equal welding mark area, two small welding marks are used instead of one large welding mark. On the one hand, it can alleviate the stress concentration problem of one large welding mark and reduce the risk of tab cracking at the welding mark site. On the other hand, the size of the large welding mark is relatively large, and the central arrangement may interfere with the welding area of the pole (electrode terminal 5) and the adapter plate.

[0191] The pole includes a positive pole (positive electrode terminal 51) and a negative pole (negative electrode terminal 52). The cross-sectional area of the pole is increased, which helps to reduce the electronic transmission impedance and improve the energy conversion efficiency of the battery cell.

[0192] The above embodiments are only used to illustrate the technical solutions of the present application, but not to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement for part or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application, and they should be covered in the scope of the present application. Especially, as long as there is no structural conflict, each technical feature mentioned in each embodiment can be combined in any way.

Claims

1. A battery cell, characterized by The battery cell comprises: a housing including a housing body formed with an opening and an end cover arranged at the opening; and an electrode assembly located in the housing, the electrode assembly including an electrode body and a tab connected to the electrode body, the electrode body including a positive electrode sheet, a negative electrode sheet, and a separator arranged in a stack along a first direction; wherein a length of the end cover along a second direction is in a range of 320 mm to 480 mm, a ratio of a minimum width of the tab along the second direction to the length of the end cover along the second direction is in a range of 0.23 to 0.35, and the second direction intersects the first direction.

2. The battery cell according to claim 1, wherein the tab includes a positive tab and a negative tab; a minimum width of the positive tab along the second direction is in a range of 90 mm to 110 mm; and / or a minimum width of the negative tab along the second direction is in a range of 90 mm to 110 mm.

3. The battery cell of claim 1, wherein, the end cover is formed with a mounting hole, and the battery cell further comprises: an electrode terminal passing through the mounting hole; and an electrical connection connecting the electrode terminal and the tab, the electrical connection including a tab connection portion connected to the tab and an electrode terminal connection portion connected to the electrode terminal; wherein the number of the tab connection portions is two, and the two tab connection portions are located on opposite sides of the electrode terminal connection portion along the first direction.

4. The battery cell according to claim 3, wherein along the first direction, the two tab connection portions are spaced apart from each other to form a clearance.

5. The battery cell according to claim 3, wherein The total cross-sectional area of the welds at the tab connecting portion of one of the electrical connectors is in the range of 300 mm 2 to 650 mm 2 .

6. The battery cell according to claim 5, wherein the tab includes a positive tab, the electrode terminal includes a positive terminal, and the electrical connection includes a first electrical connection connecting the positive tab and the positive terminal; The welding marks include a first welding mark, the positive electrode tab is welded with the tab connecting part of the first electrical connecting piece to form the first welding mark, and the total cross-sectional area of the first welding mark is in the range of 500mm 2 to 650mm 2 .

7. The battery cell according to claim 6, wherein the number of the first welds at one of the tab connection portions of the first electrical connection is a plurality, and the plurality of the first welds are arranged apart from each other along the second direction.

8. The battery cell according to claim 5, wherein the tab includes a negative tab, the electrode terminal includes a negative terminal, and the electrical connection includes a second electrical connection connecting the negative tab and the negative terminal; The welding mark includes a second welding mark, the negative electrode tab is welded with the tab connecting part of the second electric connecting piece to form the second welding mark, and the total cross-sectional area of the second welding mark is in the range of 300mm 2 to 500mm 2 .

9. The battery cell according to claim 8, wherein the number of the second welds at one of the tab connection portions of the second electrical connection is a plurality, and the plurality of the second welds are arranged apart from each other along the second direction.

10. The battery cell according to any one of claims 3 to 9, wherein The minimum cross-sectional area of the electrode terminal is in the range of 800 mm 2 to 1100 mm 2 .

11. A battery device characterized by comprising: the battery device includes: a case; and at least one battery cell according to any one of claims 1 to 10, the battery cell being accommodated in the case.

12. An electrical device, characterized by The electric device comprises the battery cell of any one of claims 1 to 10 or the battery device of claim 11 for providing electric energy.

13. An energy storage device, characterized by, The energy storage device comprises the battery cell of any one of claims 1 to 10 or the battery device of claim 11 for providing electric energy.

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