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

Abstract

The utility model discloses a battery monomer, a battery, a power utilization device and an energy storage device. The battery cell includes: a housing having an accommodation space; an electrode terminal provided in the case; and the at least one electrode assembly is arranged in the accommodating space, the electrode assembly comprises a main body part and a tab arranged on the main body part, the tab comprises a plurality of tab pieces, and the tab is directly connected with the electrode terminal. Impedance of the single battery in the charging and discharging process can be reduced, so that temperature rise is reduced.

Description

Technical Field

[0001] The present application relates to the field of battery technology, and in particular to battery cells, batteries, electrical devices and energy storage devices. Background Art

[0002] New energy batteries are being used more and more widely in life and industry. For example, new energy vehicles equipped with batteries have been widely used. In addition, batteries are also being increasingly used in areas such as energy storage.

[0003] In new energy vehicles equipped with batteries, the batteries can be used to provide power in whole or in part. In the field of energy storage, the batteries can be installed in the energy storage box or directly on the user side. With the continuous expansion of the application field of power batteries, not only higher requirements are placed on the performance of batteries, but also higher requirements are placed on the reliability and lightweight of batteries. Utility Model Content

[0004] In order to solve the above technical problems, the present application provides a highly reliable and lightweight battery cell, a battery, an electrical device and an energy storage device.

[0005] This application is implemented through the following technical solutions.

[0006] The first aspect of the present application provides a battery cell, comprising: a shell having a storage space; an electrode terminal arranged in the shell; at least one electrode assembly arranged in the storage space, the electrode assembly comprising a main body and a pole ear arranged in the main body, the pole ear comprising a plurality of pole ear sheets, and the pole ear is directly connected to the electrode terminal.

[0007] The pole ear includes multiple pole ear sheets, and the pole ear is directly connected to the electrode terminal, which can improve the current capacity to adapt to the high-rate charging and discharging requirements, and can also shorten the current path, reduce the impedance of the battery cell during the charging and discharging process, thereby reducing the temperature rise. Therefore, even if the battery cell is used in the high-rate charging and discharging scenario, it can alleviate the adverse effects of high temperature on battery performance and reduce the risk of thermal runaway of the battery cell, thereby improving the reliability of the battery cell; in addition, since the previous adapter is omitted, the battery cell and even the battery are lighter.

[0008] In some embodiments, the electrode tab has a connecting portion and a gathering portion, the connecting portion is connected between the main body portion and the gathering portion, the gathering portion is formed by stacking a plurality of the electrode tab sheets together, and the gathering portion is directly connected to the electrode terminal.

[0009] The gathered portion is formed by stacking a plurality of tab sheets together, so that when the gathered portion is directly connected to the electrode terminal, the same connection effect as that between the adapter sheet and the electrode terminal can be achieved, that is, the impedance caused by the previous use of the adapter sheet is reduced without reducing the connection effect between the tab and the electrode terminal.

[0010] In some embodiments, a first welding connection is formed in the gathering portion, and the plurality of electrode tabs are connected as a whole via the first welding connection. The gathering portion and the electrode terminal are interconnected via a second welding connection. In the same projection plane perpendicular to the thickness direction of the gathering portion, the projections of the second welding connection and the first welding connection have an overlapping portion.

[0011] Multiple pole tabs are connected as a whole through the first welding connection portion, so that the connection between the multiple pole tabs located in the gathered portion is tighter, and the second welding connection portion and the projection of the first welding connection portion have an overlapping portion, so that the connection between the gathered portion and the electrode terminal connected by the second welding connection portion is more reliable, reducing the risk of cold welding, thereby improving the overcurrent capacity during high-rate charging and discharging, and also reducing the temperature rise.

[0012] In some embodiments, in the same projection plane perpendicular to the thickness direction of the gathered portion, the projection of the second welding connection portion does not exceed the projection of the first welding connection portion.

[0013] Thus, all the second welding connection portions are located within the first welding connection portion region, further improving the connection reliability between the gathered portion and the electrode terminal.

[0014] In some embodiments, the projection of the second weld connection has an area that is 30% to 100% of the projection of the first weld connection.

[0015] The appropriate welding area between the gathered portion and the electrode terminal can not only meet the overcurrent requirement, but also play the role of overcurrent protection.

[0016] In some embodiments, the gathering portion is configured as a plate-like structure.

[0017] The internal structure of the gathered portion of the plate-like structure is more compact, so that when the gathered portion is directly connected to the electrode terminal, it can be closer to the effect of the previous connection between the adapter and the electrode terminal, thereby further improving the overcurrent performance and connection reliability.

[0018] In some embodiments, the gathered portion is formed by ultrasonic welding of a plurality of the tab sheets.

[0019] The ultrasonic welding head vibrates at high frequencies to tightly fit and compact the multiple tabs together, so that the gathered portion has a compact structure like a plate. Therefore, even if the gathered portion and the electrode terminal are welded by laser, a reliable connection can be achieved.

[0020] In some embodiments, the gathered portion is laser welded to the electrode terminal.

[0021] Since the gathered portion is connected together by stacking a plurality of tab sheets to form a compact structure, reliable connection can be achieved through laser welding as in the past through adapter sheets, thereby reducing the risk of cold welding, improving connection reliability, and also improving processing efficiency.

[0022] In some embodiments, one end of the connecting portion connected to the gathering portion is located at the center of the main body in the thickness direction.

[0023] Therefore, the central tab structure makes the current paths of each tab roughly the same, the current is more uniform, and the temperature rise of the battery cell under high-rate charge and discharge can be reduced, thus significantly improving the cycle life of the battery cell. In addition, the central tab structure is convenient for welding with the electrode terminal.

[0024] In some embodiments, the electrode terminal includes a positive terminal and a negative terminal; the tab includes a positive tab and a negative tab, the positive tab and the negative tab are respectively arranged at the same end of the main body, the positive tab is directly connected to the positive terminal, and the negative tab is directly connected to the negative terminal.

[0025] The positive electrode tab and the negative electrode tab are directly connected to the positive terminal and the negative terminal respectively, which can reduce the internal impedance of the battery, reduce the temperature rise of the battery during charging and discharging, and improve the reliability of the battery.

[0026] In some embodiments, two electrode assemblies are provided, and the electrode tabs of the two electrode assemblies have the same polarity and are connected, and the electrode tabs of each electrode assembly are directly connected to the electrode terminal through the respective retracted portions.

[0027] The two electrode assemblies are directly connected to the electrode terminals through their respective retracted parts, which can increase the battery capacity while reducing the internal impedance of the battery, lowering the temperature rise during battery charging and discharging, and improving battery reliability.

[0028] In some embodiments, the two electrode assemblies are disposed opposite to each other along the thickness direction of the main body.

[0029] The two electrode assemblies arranged opposite to each other reduce the space occupied by the shell, which is beneficial to improving the volume energy density of the battery.

[0030] The second aspect of the present application provides a battery, comprising: a box body; at least one battery cell provided by the first aspect, and the battery cell is disposed in the box body.

[0031] The third aspect of the present application provides an electrical device, and the electrical device comprises the battery cell provided by the first aspect or the battery provided by the second aspect, and the battery can supply electrical energy to the electrical device.

[0032] The fourth aspect of the present application provides an energy storage device, comprising the battery cell provided by the first aspect or the battery provided by the second aspect, and the battery can store electrical energy and can supply electrical energy.

[0033] Utility model effect:

[0034] Through the embodiments of the present application, the reliability and light weight of the battery cell and even the battery can be improved. Description of the drawings

[0035] By reading the following detailed description of the preferred embodiments, various other advantages and benefits will become clear to those of ordinary skill in the art. The drawings are only for the purpose of showing the preferred embodiments and are not considered as a limitation of the present application. Moreover, in all the drawings, the same reference numerals are used to represent the same components. In the drawings:

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

[0037] Figure 2 is a three-dimensional exploded view of a battery provided by some embodiments of the present application;

[0038] Figure 3 is a three-dimensional exploded view of a battery cell provided by some embodiments of the present application;

[0039] Figure 4 is a schematic structural diagram of an electrode assembly and an end cover connected together provided by some embodiments of the present application;

[0040] Figure 5 is an exploded view of an electrode assembly and an end cover provided by some embodiments of the present application;

[0041] Figure 6 is Figure 5 a partially enlarged schematic view of the electrode assembly in

[0042] Figure 7 is a partially enlarged schematic view of the electrode assembly provided by some other embodiments of the present application;

[0043] Figure 8 is a schematic structural diagram of an end cover provided by some embodiments of the present application;

[0044] Figure 9 A top view of an end cap provided for some embodiments of the present application;

[0045] Figure 10 A partially enlarged schematic cross-sectional view of an end cap provided in some embodiments of the present application;

[0046] Figure 11 A cross-sectional schematic diagram of a pressing member provided in some embodiments of the present application pressing a tab onto an electrode terminal.

[0047] Description of reference numerals:

[0048] 1000-Vehicles;

[0049] 100-battery; 200-controller; 300-motor;

[0050] 1-Battery;

[0051] 2-box; 3-lower box; 4-upper box;

[0052] 10-housing; 11-shell; 12-first housing wall;

[0053] 22-electrode terminal; 22a-positive terminal; 22b-negative terminal; 221-first connection portion; 221a-connection surface; 222-second connection portion; 231-positioning portion; 231a-first surface; 231b-second surface; 2211-terminal plate; 2221-terminal plate; 23-insulating member; 233-protruding portion; 234-explosion-proof valve avoidance hole; 235-liquid injection avoidance hole;

[0054] 30-electrode assembly; 31-main body; 32-ear; 32a-ear sheet; 32c-positive electrode ear; 32d-negative electrode ear; 321-connecting part; 322-folding part; 322b-second welding connection part; 322c-first welding connection part;

[0055] O-center; X-layer thickness direction; Y-thickness direction; Z-length direction; S-pressing piece. DETAILED DESCRIPTION

[0056] The following embodiments of the technical solution of the present application are described in detail in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present application, and are therefore only used as examples, and cannot be used to limit the scope of protection of the present application.

[0057] 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 terms used herein are for the purpose of describing specific embodiments only and are not intended to limit this application; the terms "including" and "having" and any variations thereof in the specification and the above drawings of this application are intended to cover non-exclusive inclusion.

[0058] In the description of the embodiments of this application, the technical terms "first", "second", "third", etc. 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. In the description of the embodiments of this application, the meaning of "a plurality of" is more than two, unless otherwise specifically defined.

[0059] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in connection with the embodiments can be included in at least one embodiment of this application. The phrase does not necessarily refer to the same embodiment at every occurrence in the specification, nor is it an independent or alternative embodiment mutually exclusive with other embodiments. Those skilled in the art will explicitly and implicitly understand that the embodiments described herein can be combined with other embodiments.

[0060] In the description of the embodiments of this application, the term "and / or" is merely a description of the associated relationship of the associated objects, indicating that three relationships can exist. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " herein generally represents an "or" relationship between the associated objects before and after.

[0061] In the description of the embodiments of this application, the orientation or positional relationship indicated by technical terms such as "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "circumferential", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the embodiments of this application and simplifying the description, rather than indicating or implying that the indicated device or element must have a specific orientation, be constructed, operated or used in a specific orientation, and thus cannot be understood as a limitation on the embodiments of this application.

[0062] In the description of the embodiments of the present application, unless otherwise clearly specified or limited, technical terms such as "installation", "connection", "attachment", and "fixation" shall be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral one; it may also be a mechanical connection or an electrical connection; it may be a direct connection or an indirect connection through an intermediate medium, and it may be the internal communication of two components or the interaction relationship between two components. 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 circumstances.

[0063] In the description of the embodiments of the present application, unless otherwise clearly specified or limited, the technical term "contact" shall be understood in a broad sense. It may be direct contact or contact through an intermediate medium layer. It may be contact where there is basically no mutual force between the two contacting objects, or contact where there is a mutual force between the two contacting objects.

[0064] In the embodiments of the present application, the battery cell may be a secondary battery, which refers to a battery that can be reused by activating the active material through charging after the battery cell discharges.

[0065] The battery cell may be a lithium-ion battery, a sodium-ion battery, a sodium-lithium-ion battery, a lithium-metal battery, a sodium-metal battery, a lithium-sulfur battery, a magnesium-ion battery, a nickel-metal hydride battery, a nickel-cadmium battery, a lead-acid battery, etc., and the embodiments of the present application do not limit this.

[0066] The battery cell generally includes an electrode assembly. The electrode assembly includes a positive electrode, a negative electrode, and a separator. During the charge and discharge process of the battery, active ions (such as lithium ions) intercalate and deintercalate back and forth between the positive electrode and the negative electrode. The separator is disposed between the positive electrode and the negative electrode, which can prevent short circuit between the positive and negative electrodes and at the same time allow active ions to pass through.

[0067] In some embodiments, the positive electrode may be a positive electrode sheet, and the positive electrode sheet 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.

[0068] As an example, the positive electrode current collector has two surfaces opposite to each other in its own thickness direction, and the positive electrode active material is disposed on any one or both of the two opposite surfaces of the positive electrode current collector.

[0069] As an example, the positive electrode current collector can be a metal foil or a composite current collector. For example, as the metal foil, aluminum or stainless steel with a silver surface treatment, stainless steel, copper, aluminum, nickel, carbon electrodes, carbon, nickel, or titanium, etc. can be used. The composite current collector can include a polymer material substrate layer and a metal layer. The composite current collector can be formed by forming a metal material (such as aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver, and silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0070] As an example, the positive electrode active material can include at least one of the following materials: lithium-containing phosphates, lithium transition metal oxides, and their respective modified compounds. However, this application is not limited to these materials, and other conventional materials that can be used as battery positive electrode active materials can also be used. These positive electrode active materials can be used alone or in combination of two or more. Among them, examples of lithium-containing phosphates can include but are not limited to lithium iron phosphate (such as LiFePO 4 (which can also be abbreviated as LFP)), a composite material of lithium iron phosphate and carbon, lithium manganese phosphate (such as LiMnPO 4 ), a composite material of lithium manganese phosphate and carbon, lithium manganese iron phosphate, and at least one of a composite material of lithium manganese iron phosphate and carbon.

[0071] In some embodiments, the positive electrode can be a foam metal. The foam metal can be foam nickel, foam copper, foam aluminum, foam alloy, or foam carbon, etc. When the foam metal is used as the positive electrode, the positive electrode active material may not be provided on the surface of the foam metal, and of course, the positive electrode active material can also be provided. As an example, a lithium source material, potassium metal, or sodium metal can also be filled and / or deposited in the foam metal, and the lithium source material is lithium metal and / or lithium-rich material.

[0072] In some embodiments, the negative electrode can be a negative electrode sheet, and the negative electrode sheet can include a negative electrode current collector.

[0073] As an example, the negative electrode current collector can be a metal foil, a foam metal, or a composite current collector. For example, as the metal foil, aluminum or stainless steel with a silver surface treatment, stainless steel, copper, aluminum, nickel, carbon electrodes, carbon, nickel, or titanium, etc. can be used. The composite current collector can include a polymer material substrate layer and a metal layer. The foam metal can be foam nickel, foam copper, foam aluminum, foam alloy, or foam carbon, etc. The composite current collector can be formed by forming a metal material (such as copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver, and silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.). 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.

[0074] In some embodiments, the electrode assembly further includes a separator disposed between the positive electrode and the negative electrode.

[0075] In some embodiments, the separator is a separator membrane. The present application does not particularly limit the type of the separator membrane, and any well-known porous structure separator membrane with good chemical stability and mechanical stability can be selected.

[0076] As an example, the main material of the separator membrane can be selected from at least one of fiberglass, non-woven fabric, polyethylene, polypropylene, polyvinylidene fluoride, and ceramics.

[0077] In some embodiments, the separator is a solid electrolyte. The solid electrolyte is disposed between the positive electrode and the negative electrode, and simultaneously functions to transport ions and isolate the positive and negative electrodes.

[0078] In some embodiments, the battery cell further includes an electrolyte that functions to conduct ions between the positive and negative electrodes. The present application does not specifically limit the type of the electrolyte, and it can be selected according to requirements. The electrolyte can be liquid, gel-like, or solid.

[0079] In some embodiments, the electrode assembly is of a wound structure. The positive electrode sheet and the negative electrode sheet are wound into a wound structure.

[0080] In some embodiments, the electrode assembly is of a stacked structure.

[0081] As an example, multiple positive electrode sheets and multiple negative electrode sheets can be respectively provided, and the multiple positive electrode sheets and the multiple negative electrode sheets are alternately stacked.

[0082] As an example, multiple positive electrode sheets can be provided, and the negative electrode sheet is folded to form multiple stacked folding segments, and a positive electrode sheet is clamped between adjacent folding segments.

[0083] As an example, both the positive electrode sheet and the negative electrode sheet are folded to form multiple stacked folding segments.

[0084] As an example, multiple separators can be provided and are respectively disposed between any adjacent positive electrode sheets or negative electrode sheets.

[0085] As an example, the separator can be continuously provided and is disposed between any adjacent positive electrode sheets or negative electrode sheets by folding or winding.

[0086] In some embodiments, the shape of the electrode assembly can be cylindrical, flat, or multi-prismatic, etc.

[0087] In some embodiments, the electrode assembly is provided with tabs, and the tabs can lead the current out of the electrode assembly. The tabs include a positive tab and a negative tab.

[0088] In some embodiments, a battery cell may include a housing. The housing is used to encapsulate components such as an electrode assembly and an electrolyte. The housing can be a steel shell, an aluminum shell, a plastic shell (such as polypropylene), a composite metal shell (such as a copper-aluminum composite housing), or an aluminum-plastic film, etc.

[0089] As an example, the battery cell can be a cylindrical battery, a prismatic battery, a pouch battery, or a battery of other shapes. The prismatic battery includes a square shell battery, a blade-shaped battery, a multi-prismatic battery, and the multi-prismatic battery is, for example, a hexagonal prism battery, etc. There is no particular limitation in this application.

[0090] In some embodiments, the housing includes an end cap and a housing body. The housing body is provided with an opening, and the end cap closes the opening to form a sealed space for accommodating substances such as an electrode assembly and an electrolyte. The housing body can be provided with one or more openings. One or more end caps can also be provided.

[0091] In some embodiments, a pressure relief mechanism is provided on the housing. The pressure relief mechanism is used to release the internal pressure of the battery.

[0092] In some embodiments, the battery mentioned in this application can be a battery module. The battery module includes one or more battery cells to provide a single physical module with a higher voltage and capacity. When there are multiple battery cells, the multiple battery cells are connected in series, parallel, or in a hybrid connection through a busbar component. The multiple battery cells are arranged and fixed to form a battery module.

[0093] In some embodiments, the battery mentioned in this application can also be a battery pack. The battery pack includes a box body and at least one battery cell or battery module, and the battery cell or battery module is accommodated in the box body.

[0094] In some embodiments, the box body can be a part of the chassis structure of a vehicle. For example, a part of the box body can become at least a part of the floor of the vehicle, or a part of the box body can become at least a part of the crossbeam and longitudinal beam of the vehicle.

[0095] Next, a detailed description of this application will be given.

[0096] Currently, new energy batteries are being applied more and more widely in life and industry. New energy batteries are not only applied to energy storage power systems such as hydropower, thermal power, wind power, and solar power stations, but also widely applied to electric transportation tools such as electric bicycles, electric motorcycles, and electric vehicles, as well as multiple fields such as aerospace. With the continuous expansion of the application fields of power batteries, higher requirements are not only put forward for the performance of the batteries, but also for the reliability and lightweight of the batteries.

[0097] During the charging and discharging process of a battery cell, heat is generated. The greater the internal impedance of the battery cell, the more obvious the heat generation. Usually, the tab of the battery cell is connected to the electrode terminal through a transition piece. During the charging and discharging process of the battery cell, a large impedance will be generated in the transition piece, resulting in serious heat generation of the battery cell. In addition, for a battery cell with high-rate charging and discharging performance, since the current flowing through the transition piece is greater, the heat generation is more obvious. This will have an adverse impact on the cycle life of the battery cell and may even pose a risk of thermal runaway, resulting in poor reliability of the battery cell and even the battery.

[0098] In view of this, the present application provides a battery, including: a housing having an accommodation space; an electrode terminal disposed on the housing; at least one electrode assembly disposed in the accommodation space, the electrode assembly including a main body portion and a tab disposed on the main body portion, the tab including a plurality of tab pieces, and the tab being directly connected to the electrode terminal.

[0099] By having the tab include a plurality of tab pieces and the tab being directly connected to the electrode terminal, while being able to improve the overcurrent capacity to meet the high-rate charging and discharging requirements, it is also possible to shorten the overcurrent path, reduce the impedance during the charging and discharging process of the battery cell, thereby reducing the temperature rise. Thus, even in the usage scenario of high-rate charging and discharging of the battery cell, it is possible to alleviate the adverse impact of high temperature on the performance of the battery cell and reduce the risk of thermal runaway of the battery cell, thereby improving the reliability of the battery cell and even the battery; in addition, since the conventional transition piece is omitted, the battery cell and even the battery are made lighter.

[0100] An embodiment of the present application further provides a battery including at least one battery cell. The battery can be but is not limited to being used in power storage power systems, vehicles, ships, aircraft, and other electrical devices.

[0101] The battery provided by the embodiment of the present application can be a battery pack. The battery pack can also be but is not limited to being used in power storage power systems, vehicles, ships, aircraft, and other electrical devices. Using the battery pack can provide higher total energy.

[0102] An embodiment of the present application provides an electrical device including the above battery cell or battery for providing electrical energy. The electrical device can be but is not limited to mobile phones, tablets, laptop computers, electric toys, power tools, battery cars, electric vehicles, ships, spacecraft, etc. Among them, the electric toy can include fixed or mobile electric toys, such as game consoles, electric vehicle toys, electric ship toys, and electric aircraft toys, etc. The spacecraft can include airplanes, rockets, space shuttles, and spaceships, etc.

[0103] In the following embodiments, for the convenience of description, the electrical device in an embodiment of the present application is taken as the vehicle 1000 as an example for description. The following is described with reference to the drawings.

[0104] Figure 1 A structural schematic diagram of vehicle 1000 provided for 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, a range-extended vehicle, etc. As Figure 1 shown, a battery 100 is disposed inside vehicle 1000. The battery 100 can be disposed at the bottom, head, or tail of vehicle 1000. The battery 100 can be used to supply power to vehicle 1000. For example, the battery 100 can serve as the operating power source of vehicle 1000. Vehicle 1000 can also include a controller 200 and a motor 300. The controller 200 is used to control the battery 100 to supply power to the motor 300. For example, it is used for the working power requirements during the start-up, navigation, and driving of vehicle 1000.

[0105] In some embodiments of the present application, the battery 100 can not only serve as the operating power source of vehicle 1000, but also serve as the driving power source of vehicle 1000, replacing or partially replacing fuel or natural gas to provide driving power for vehicle 1000.

[0106] Figure 2 A three-dimensional exploded view of the battery provided for some embodiments of the present application. As Figure 2 shown, the battery 100 includes a box body 2. The box body 2 includes a lower box body 3 and an upper box body 4. The lower box body 3 and the upper box body 4 are covered together to form an accommodation space for accommodating battery cells 1.

[0107] In the battery 100, there can be multiple battery cells 1. The multiple battery cells 1 can be connected in series, parallel, or in a mixed connection. A mixed connection means that there are both series and parallel connections among the multiple battery cells 1. The multiple battery cells 1 can be directly connected in series, parallel, or in a mixed connection together, and then the whole formed by the multiple battery cells 1 is placed in the accommodation space formed by covering the lower box body 3 and the upper box body 4. Of course, the battery 100 can also be in the form that multiple battery cells 1 are first connected in series, parallel, or in a mixed connection to form battery modules, and then the multiple battery modules are connected in series, parallel, or in a mixed connection to form a whole and are accommodated in the accommodation space formed by covering the lower box body 3 and the upper box body 4. The battery 100 can also include other structures. For example, the battery 100 can also include a busbar component for realizing the electrical connection among the multiple battery cells 1.

[0108] Next, with reference to Figures 3 to 11 Some embodiments of the present application will be described in detail.

[0109] Figure 3 A three-dimensional exploded view of the battery cell provided for some embodiments of the present application; Figure 4 A structural schematic diagram of the electrode assembly connected to the end cover provided for some embodiments of the present application; Figure 5Exploded view of the electrode assembly and the end cap provided for some embodiments of the present application; wherein, Figure 4 The positional relationship between the electrode assembly 30 and the end cap shown in Figure 3 can be regarded as the perspective of flattening the electrode assembly 30 with two sides facing each other in Figure 3 to an end-to-end state in a direction away from each other. At this time, the tabs of the electrode assembly 30 are flattened from the

[0110] Figure 6 bent form in Figure 5 to a straight form; it can also be regarded as the perspective presented during the connection process between the tab 32 and the electrode terminal 22 during battery manufacturing. Figure 7 Partial enlarged view of the structure of the electrode assembly provided for other embodiments of the present application; wherein, Figure 6 and Figure 7 show the perspective of the tabs 32 of the electrode assembly 30 in an unbent state. As for the perspective of the tabs 32 in a bent state, reference can be made to the electrode assembly 30 shown in Figure 3 .

[0111] Figure 8 Structure diagram of the end cap provided for some embodiments of the present application, wherein, a pressing member S is respectively placed on two electrode terminals 22 as shown in the figure; Figure 9 Top view of the end cap provided for some embodiments of the present application, wherein, a pressing member S is placed on one of the two electrode terminals 22, and the other is not provided with a pressing member; Figure 10 Partial cross-sectional enlarged view of the end cap provided for some embodiments of the present application, wherein, the pressing member S is not placed on the electrode terminal 22; Figure 11 Cross-sectional view of the pressing member pressing and fixing the tab on the electrode terminal provided for some embodiments of the present application.

[0112] In the embodiments of the present application, it is defined that the arrow Z in the figure represents the first direction Z, the arrow Y represents the second direction Y, and the arrow X represents the third direction X. The first direction Z, the second direction Y, and the third direction X are perpendicular to each other in pairs.

[0113] In some embodiments, the arrow X can also represent the stacking direction X of a plurality of tab pieces 32a, the thickness direction X of the end cap, the arrow Y can also represent the width direction Y of the end cap, and the arrow Z can also represent the length direction Z of the main body portion 31, the length direction Z of the end cap. In addition, those skilled in the art can understand that, Figures 4 to 7 the main body portion 31 in Figure 3 is the flattened perspective of the main body portion 31 in Figures 4 to 7 , therefore, Figure 3The thickness direction of the main body portion 31 is perpendicular to the thickness direction of the folding portion 322.

[0114] An embodiment of the present application provides a battery cell 1. Referring to Figures 3 to 7 , the battery cell 1 includes: a housing 10, an electrode terminal 22, and at least one electrode assembly 30. The housing 10 has an accommodation space A; the electrode terminal 22 is disposed on the housing 10; at least one electrode assembly 30 is disposed in the accommodation space A. The electrode assembly 30 includes a main body portion 31 and a tab 32 disposed on the main body portion 31. The tab 32 includes a plurality of tab pieces 32a, and the tab 32 is directly connected to the electrode terminal 22.

[0115] The housing 10 has an accommodation space A for accommodating the electrode assembly 30. In addition, the accommodation space A can also accommodate electrolyte and other components.

[0116] Exemplarily, referring to Figure 3 , the housing 10 has a plurality of housing walls surrounding the accommodation space A. Among the plurality of housing walls, there is a first housing wall 12. The first housing wall 12 can be an end cover of the battery cell 1. The remaining housing walls among the plurality of housing walls enclose a housing 11 with an opening. The electrode assembly 30 is received in the accommodation space A through the opening, and the opening is closed by the first housing wall 12 to form the accommodation space A for accommodating the electrode assembly 30. The electrode terminal 22 can be disposed on the first housing wall 12.

[0117] The shape of the first housing wall 12 can be adapted to the shape of the opening of the housing 11. The material of the first housing wall 12 can be various, for example, copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc. The embodiments of the present application do not make special restrictions on this. Exemplarily, the first housing wall 12 can be made of a material (such as aluminum alloy) with a certain hardness and strength. In this way, the first housing wall 12 is not easily deformed when being squeezed and collided, so that the battery cell 1 can have higher structural strength.

[0118] In some embodiments, an insulating member can be further disposed between the first housing wall 12 and the opening of the housing 11 to reduce the risk of short circuit and achieve a sealing effect. In some embodiments, the first housing wall 12 can further include a pressure relief mechanism for releasing the internal pressure when the internal pressure of the battery cell 1 reaches a threshold value.

[0119] The housing 10 can have various shapes, such as a cuboid shape, a cylindrical shape, a hexagonal prism shape, etc. The appropriate housing 10 can be determined according to the specific shape of the electrode assembly 30. The material of the housing 10 can be a metal material or a non-metal material, for example, copper, iron, aluminum, stainless steel, aluminum alloy, plastic, aluminum-plastic, etc. The embodiments of the present application do not make special restrictions on this.

[0120] The electrode terminal 22 is electrically connected to the electrode assembly 30 and is used for outputting or inputting electric energy. When there are multiple battery cells 1, the electrode terminals 22 of each battery cell 1 can also be connected through a busbar component, so that multiple battery cells are connected in series and / or in parallel.

[0121] The number of electrode assemblies 30 can be one, two or more. Each electrode assembly 30 includes a main body 31 and a tab 32 disposed on the main body 31. Exemplarily, the main body 31 includes a positive electrode plate, a negative electrode plate, and a separator sandwiched between the positive electrode plate and the negative electrode plate. In one example, the positive electrode plate, the separator, and the negative electrode plate can be wound at least two turns to form a wound structure; in another example, the positive electrode plate, the separator, and the negative electrode plate can also be stacked to form a stacked structure.

[0122] The tab 32 includes a plurality of tab pieces 32a( Figure 6 、 Figure 7 as shown), each tab piece 32a is connected to the main body 31, and each tab piece 32a can be integrally formed with the main body 31.

[0123] The tab 32 can conduct the current out of the main body 31. The plurality of tab pieces 32a can improve the overcurrent capacity and better meet the requirements of high-rate charge and discharge.

[0124] The tab 32 includes a plurality of tab pieces 32a, and the tab 32 is directly connected to the electrode terminal 22. While improving the overcurrent capacity to meet the requirements of high-rate charge and discharge, it can also shorten the overcurrent path, reduce the impedance of the battery cell 1 during charge and discharge, thereby reducing the temperature rise. Thus, even in the scenario of high-rate charge and discharge of the battery cell 1, it can alleviate the adverse effects of high temperature on the battery performance and reduce the risk of thermal runaway of the battery cell 1, thereby improving the reliability of the battery cell 1 and even the battery 100; in addition, since the conventional adapter plate is omitted, the battery cell 1 and even the battery 100 are made lighter.

[0125] In some embodiments, the tab 32 has a connecting portion 321 and a converging portion 322. The connecting portion 321 is connected between the main body 31 and the converging portion 322. The converging portion 322 is formed by laminating and connecting a plurality of tab pieces 32a together, and the converging portion 322 is directly connected to the electrode terminal 22.

[0126] The converging portion 322 is formed by laminating and connecting a plurality of tab pieces 32a together means that the plurality of tab pieces 32a are laminated in their own thickness direction and each tab piece 32a is close to and concentrated with each other, so that the converging portion 322 is formed into a relatively compact integral structure.

[0127] After the electrode assembly 30 is wound to form a wound structure, the plurality of tab pieces 32a may be relatively loose, and between each tab piece 32a in the lamination direction( Figure 6The gap in the middle third direction (X) is relatively large, and the loose connection between the pole tab 32a and the electrode terminal 22 is prone to unreliable connection problems. For example, there is a risk of cold welding during the welding process, resulting in poor current capacity and failure to meet high-rate charge and discharge requirements.

[0128] In this regard, a plurality of loose tabs 32a are gathered together toward the same position and stacked together to form a compact gathering portion 322, and the compact gathering portion 322 is directly connected to the electrode terminal 22 (for example, by laser welding), so that a reliable connection can be achieved. As an example, the compact gathering portion 322 can be a plate-like structure similar to the conventional adapter sheet, so that when the gathering portion 322 is directly connected to the electrode terminal 22 (for example, by laser welding), the same connection effect as that of the adapter sheet and the electrode terminal 22 can be basically achieved.

[0129] The gathered portion is connected together by stacking a plurality of tab sheets 32a to form a compact integrated structure, so that the gathered portion 322 is more reliably directly connected to the electrode terminal 22, reducing the risk of false connection, thereby improving the current carrying capacity of the tab 32. In other words, even if the conventional adapter is omitted, the current carrying capacity of the tab 32 can be improved to meet the high-rate charge and discharge requirements without reducing the connection effect between the tab 32 and the electrode terminal 22, and the impedance of the battery cell 1 during the charge and discharge process can be reduced, thereby reducing the temperature rise, alleviating the adverse effects of the high temperature of the battery cell 1 on the performance and cycle life, and also reducing the risk of thermal runaway of the battery cell 1, thereby improving the reliability of the battery cell 1 and even the battery 100.

[0130] In some embodiments, a first welding connection portion 322c is formed in the gathering portion 322, and a plurality of electrode tabs 32a are connected as a whole through the first welding connection portion 322c. The gathering portion 322 and the electrode terminal 22 are interconnected through the second welding connection portion 322b. In the same projection plane perpendicular to the thickness direction X of the gathering portion 322, the projections of the second welding connection portion 322b and the first welding connection portion 322c have an overlapping portion.

[0131] In the same projection plane perpendicular to the thickness direction X of the gathered portion 322, the projections of the second welding connection portion 322b and the first welding connection portion 322c have an overlapping portion. It can be understood that in the gathered portion 322, a plurality of pole tabs 32a are connected together by welding to form a first welding connection portion 322c having a certain area, and within the area of ​​the first welding connection portion 322c, the gathered portion 322 and the electrode terminal 22 are connected together by welding to form a second welding connection portion 322b.

[0132] For example, first, ultrasonic pre-welding can be performed on the multiple pole tabs 32a located in the gathering portion 322, so as to form a first welding connection portion 322c (ultrasonic welding mark) in the gathering portion 322. The first welding connection portion 322c enables the multiple pole tabs 32a located in the gathering portion 322 to be tightly connected together to form an integrated structure. Then, the gathering portion 322 is connected to the electrode terminal 22 by laser welding in the area of ​​the first welding connection portion 322c, so as to form a second welding connection portion 322b (laser welding mark) between the gathering portion 322 and the electrode terminal 22, so that the second welding connection portion 322b at least partially overlaps with the first welding connection portion 322c.

[0133] Thus, the plurality of pole tabs 32a are connected as a whole through the first welding connection portion 322c, so that the connection between the plurality of pole tabs 32a located in the gathered portion is tighter, and the projection of the second welding connection portion 322b and the first welding connection portion 322c has an overlapping portion, so that the connection between the gathered portion 322 and the electrode terminal 22 connected by the second welding connection portion 322b is more reliable, reducing the risk of cold welding, thereby improving the overcurrent capacity during high-rate charging and discharging, and also reducing the temperature rise.

[0134] In some embodiments, in the same projection plane perpendicular to the thickness direction X of the gathered portion 322 , the projection of the second welding connection portion 322 b does not exceed the projection of the first welding connection portion 322 c .

[0135] Therefore, all the second welding connection portions 322 b are located within the first welding connection portion 322 c , further improving the connection reliability between the gathered portion 322 and the electrode terminal 22 .

[0136] In some embodiments, the projection area of ​​the second welding connection 322b accounts for 30% to 100% of the projection area of ​​the first welding connection 322c. For example, the projection area of ​​the second welding connection 322b accounts for 30%, 35%, 40%, 45%, 50%, 55%, 60%, 70%, 80%, 90%, 100% of the projection area of ​​the first welding connection 322c.

[0137] The welding area between the gathered portion 322 and the electrode terminal 22 is within a suitable range, which can not only meet the overcurrent requirement but also play a role in overcurrent protection.

[0138] In some embodiments, the gathered portion 322 is configured as a plate-like structure.

[0139] The plate-like structure may be rectangular, square, oval or other shapes.

[0140] The internal structure of the folding part 322 of the plate-like structure is more compact. When the folding part 322 is directly connected to the electrode terminal 22, it can be closer to the connection effect between the conventional adapter plate and the electrode terminal 22, thereby further improving the overcurrent capacity and connection reliability.

[0141] In some embodiments, along the layer thickness direction X of the folding part 322, the folding part 322 and the electrode terminal 22 have an overlapping part.

[0142] The folding part 322 and the electrode terminal 22 are stacked with each other along the layer thickness direction X of the folding part 322. The folding part 322 can completely overlap with the electrode terminal 22 or partially overlap with the electrode terminal 22.

[0143] Thus, the overcurrent path of the tab 32 can be further shortened, the impedance can be reduced, the battery temperature can be further lowered, and the battery performance and reliability can be improved.

[0144] In some embodiments, one end of the connecting part 321 connected to the folding part 322 is located on one side of the center O in the thickness direction of the main body part 31 ( Figure 7 as shown) or at the center O in the thickness direction of the main body part 31 ( Figure 6 as shown).

[0145] Referring to Figure 7 , the plurality of tab pieces 32a all converge towards one side of the center O in the thickness direction of the main body part 31 and thus the folding part 322 deviates from the center O.

[0146] The plurality of tab pieces 32a form a centered folding part 322, which helps to reduce the internal resistance of the battery cell 1, reduce the temperature rise of the battery cell 1 during high-rate discharge, and improve the battery performance and reliability.

[0147] Referring to Figure 6 , one end of the connecting part 321 connected to the folding part 322 is generally located at the center O in the thickness direction of the main body part 31.

[0148] The plurality of tab pieces 32a all converge towards the center O in the thickness direction ( Figure 6 the X direction in Figure 3 the Y direction in) of the main body part 31 and thus form a centered folding part 322. One end of the connecting part 321 connected to the folding part 322 being generally located at the center O in the thickness direction of the main body part 31 should be understood in a broad sense, and can be understood as within the allowable manufacturing error or measurement error range.

[0149] Thus, the converging part 322 of the tab 32 is centered, making the current-carrying paths of the tab pieces 32a substantially the same, and the current-carrying is more uniform, which can reduce the temperature rise of the battery cell 1 under high-rate charge and discharge. Therefore, the cycle life of the battery cell 1 can be significantly improved. In addition, the centered structure of the tab 32 facilitates welding with the electrode terminal 22.

[0150] In some embodiments, referring to Figure 4 and Figure 5 , the electrode terminal 22 includes a positive electrode terminal 22a and a negative electrode terminal 22b; the tab 32 includes a positive tab 32c and a negative tab 32d. The positive tab 32c and the negative tab 32d are respectively disposed at the same end of the main body portion 31. The positive tab 32c is directly connected to the positive electrode terminal 22a, and the negative tab 32d is directly connected to the negative electrode terminal 22b.

[0151] Along the length direction Z of the end cap, the positive electrode terminal 22a and the negative electrode terminal 22b are spaced apart. The positive tab 32c and the negative tab 32d are respectively led out from the same end of the main body portion 31 and are spaced apart along the length direction Z of the electrode assembly 30. The positive tab 32c includes a plurality of positive tab pieces, and the plurality of positive tab pieces are stacked and connected together to form a positive converging portion, and the positive converging portion is directly connected to the positive electrode terminal 22a; the negative tab 32d includes a plurality of negative tab pieces, and the plurality of negative tab pieces are stacked and connected together to form a negative converging portion, and the negative converging portion is directly connected to the negative electrode terminal 22b.

[0152] The positive tab 32c and the negative tab 32d are directly connected to the positive electrode terminal 22a and the negative electrode terminal 22b respectively, which can reduce the internal impedance of the battery, lower the temperature rise during battery charge and discharge, and improve the battery reliability. In addition, the positive tab 32c and the negative tab 32d are disposed at the same end of the main body portion 31, which helps to improve the utilization rate of the housing space, thereby increasing the volume energy density of the battery cell 1.

[0153] In some embodiments, at least two electrode assemblies 30 are provided, and the tabs of at least two electrode assemblies 30 with the same polarity are connected. The tabs 32 of each electrode assembly 30 are directly connected to the electrode terminal 22 through their respective converging parts 322.

[0154] At least two electrode assemblies 30 are directly connected to the electrode terminal 22 through their respective converging parts 322, which can reduce the internal impedance of the battery cell 1, lower the temperature rise during battery charge and discharge, improve the battery reliability, and also increase the battery capacity, and better meet the high-rate discharge requirements.

[0155] In some embodiments, referring to Figures 8 to 11 , the electrode terminal 22 penetrates through the first housing wall 12 and has a first connection portion 221 located in the accommodation space A ( Figure 3 shown), and the first connection portion 221 has a direction along the thickness direction X of the first housing wall 12 (Figure 8 in the third direction X) close to the connection surface 221a of the electrode assembly 30, the connection surface 221a is connected to the tab 32; the insulating member 23 includes a positioning portion 231, the positioning portion 231 is disposed around the outer periphery of the first connection portion 221, and the positioning portion 231 has a first surface 231a on the side close to the electrode assembly 30 along the thickness direction X of the first outer shell wall, and the first surface 231a is flush with at least a part of the connection surface 221a close to the positioning portion 231.

[0156] The electrode terminal 22 is disposed on the first outer shell wall 12 and is used to connect to the tab 32 to output and input electric energy. When there are multiple battery cells 1, the electrode terminals 22 of each battery cell 1 can also be connected through a bus bar component, so that multiple battery cells 1 are connected in series and / or in parallel. The material of the electrode terminal 22 can be various, for example, conductive metals such as copper, iron, aluminum, stainless steel, aluminum alloy, etc. Exemplarily, the electrode terminal 22 sometimes exists in the form of a terminal post.

[0157] The electrode terminal 22 penetrates the first outer shell wall 12 and has a first connection portion 221 located in the accommodation space A. It can be that the electrode terminal 22 has at least a part of the first connection portion 221 protruding from one side along the thickness direction X (the third direction X) of the first outer shell wall, that is, along the thickness direction X of the first outer shell wall, the first connection portion 221 has a height H exceeding the first outer shell wall 12 1 . Refer to Figure 11 , the height H 1 is the distance between the surface of the first connection portion 221 on the side far from the first outer shell wall 12 (the connection surface 221a) and the surface of the first outer shell wall 12 on the side far from the electrode assembly 30 along the thickness direction X of the first outer shell wall. Exemplarily, see Figure 3 and Figure 11 , along the thickness direction X of the first outer shell wall, a part of the first connection portion 221 protrudes into the accommodation space A within the first outer shell wall 12, and another part passes through the first outer shell wall 12 and extends to the outside of the outer shell 10 and is connected to the second connection portion 222, and the second connection portion 222 can be used to connect an external bus bar component.

[0158] The first connection portion 221 has a connection surface 221a on the side close to the electrode assembly 30 along the thickness direction X of the first outer shell wall, and the first connection portion 221 is connected to the tab 32 through the connection surface 221a. The connection surface 221a can be directly connected to the tab 32. The connection method can be welding, bonding, etc. The shape of the connection surface 221a can be square, circular, oval or other shapes.

[0159] The insulating member 23 is used to isolate the electrode terminal 22 from the first outer shell wall 12 to reduce the risk of short circuit. The material of the insulating member 23 can be a material with insulating properties such as plastic, rubber, etc.

[0160] The insulating member 23 includes a positioning portion 231, which is disposed around the outer periphery of the first connecting portion 221, and may be along the first shell wall thickness direction X. The positioning portion 231 protrudes from the first shell wall 12 located on the same side of the first connecting portion 221. The positioning portion 231 may completely or partially surround the first connecting portion 221, and play a role in positioning and insulating the first connecting portion 221. For example, the positioning portion 231 is in a closed ring shape, surrounding the outer periphery of the first connecting portion 221.

[0161] The positioning portion 231 has a first surface 231a close to one side of the electrode assembly 30 along the first shell wall thickness direction X, and the first surface 231a is flush with the connection surface 221a at least close to the positioning portion 231. The flushness of the first surface 231a with the connection surface 221a at least close to the positioning portion 231 can be understood as that along the first shell wall thickness direction X, the first surface 231a is slightly lower or slightly higher or flush with the connection surface 221a, and the height difference between the two can be within the range allowed by the processing error. The first surface 231a can be flush with the portion of the connection surface 221a close to the positioning portion 231, or the first surface 231a is flush with the connection surface 221a as a whole. For example, the connection surface 221a as a whole can be a plane, and the first surface 231a is flush with the plane.

[0162] The first surface 231a can be understood as having a specified extension dimension along the first direction Z (the length direction of the first shell wall) and / or the second direction Y (the width direction of the first shell wall), so that when the pressing member S presses the pole tab 32 to the electrode terminal 22, the first surface 231a can provide the pressing member S with sufficient support space to support the pressing member S. As for the range of the extension dimension, it can be determined based on the size of the pressing member so that the support space formed by the first surface 231a can reach the extent of supporting the pressing member S. The first surface 231a supporting the pressing member S can be understood as, when the pressing member S presses the pole tab 32, the pressing member S can be fully supported by the first surface 231a, that is, the pressing member S is entirely located on the first surface 231a; or, a portion of the pressing member S is supported by the first surface 231a, that is, a portion of the pressing member S is located on the first surface 231a, for example, see Figure 11 , a part of the pressing member S is supported by the first surface 231a, and another part is supported by the connecting surface 221a of the first connecting portion 221, that is, the first surface 231a of the positioning portion 231 and the connecting surface 221a of the first connecting portion 221 jointly support the pressing member S. Of course, the pressing member S can also be fully supported by the first surface 231a.

[0163] As an example, see Figure 9 , Figure 10 and Figure 11, in the process of directly welding the tab 32 to the electrode terminal 22, the pressing member S first presses the tab 32 against the connection surface 221a through the pressing member S, so that the tab 32 is located between the connection surface 221a and the pressing member S, and the pressing member S surrounds the welding area between the tab 32 and the connection surface 221a. For example, the center of the pressing member S can be approximately coincident with the center of the first connection portion 221. The pressing member S is jointly supported by the first surface 231a of the positioning portion 231 and the connection surface 221a of the first connection portion 221. Thus, the tab 32 is pressed more closely against the connection surface 221a. Then, the welding head extends into the annular space of the pressing member S to perform a welding operation on the tab 32 and the connection surface 221a, and the connection surface 221a and the tab 32 are firmly welded together. The pressing member S can also reduce the spattering of particulate matter during the welding process and reduce the short-circuit risk of the battery cell 1.

[0164] Since the positioning portion has the first surface 231a and the first surface 231a is flush with the connection surface 221a of the first connection portion 221, in the process of connecting the tab 32 to the electrode terminal 22, the first surface 231a can provide a support space for the pressing member S, thereby reducing the gap between the tab 32 and the electrode terminal 22, and further making the connection between the tab and the electrode terminal more reliable, improving the connection reliability. At the same time, it will not excessively increase the weight of the battery cell 1 and will not excessively increase the cost, which is beneficial to the lightweight of the battery and the control of the cost. If a support space is provided for the pressing member by increasing the volume of the electrode terminal 22, the weight of the battery cell 1 will increase significantly, which is not conducive to the lightweight of the battery cell 1 and the cost is high.

[0165] In some embodiments, referring to Figure 9 , Figure 10 and Figure 11 , the pressing member S has a pressing surface S1, and the pressing surface S1 is used to press the tab 32 against the connection surface 221a. The dimension of the connection surface 221a along the length direction Z of the first outer shell wall is D 1 , the dimension of the first surface 231a along the length direction Z of the first outer shell wall is D 2 , the dimension of the pressing surface S1 along the length direction Z of the first outer shell wall is D 3 , the dimension of the connection surface 221a along the width direction Y of the first outer shell wall is W 1 , the dimension of the first surface 231a along the width direction Y of the first outer shell wall is W 2 , the dimension of the pressing surface S1 along the width direction Y of the first outer shell wall is W 3 , where D 1 +2D 2 ≥D 3 , W 1 +2W 2 ≥W 3 .

[0166] D 3 may be the distance between two opposite outer edges of the pressing member S along the length direction Z of the first housing wall, W 3 may be the distance between two opposite outer edges of the pressing member S along the width direction Y of the first housing wall. The dimension D of the positioning portion 231 along the length direction Z of the first housing wall 2 and the dimension W along the width direction Y of the first housing wall 2 can be adaptively adjusted according to the size of the pressing member S.

[0167] In the process of connecting the tab 32 to the electrode terminal 22, the tab 32 is pressed against the connection surface 221a of the first connection portion 221 by the pressing member S. Due to D 1 +2D 2 ≥D 3 , W 1 +2W 2 ≥W 3 , at least part of the pressing member S is supported by the first surface 231a of the positioning portion 231. Thus, the tab 32 is pressed more closely against the connection surface 221a of the first connection portion 221, improving the connection reliability.

[0168] In some embodiments, the absolute value of the height difference between the first surface 231a and the connection surface 221a along the thickness direction X of the first housing wall is in the range of 0 mm to 0.3 mm.

[0169] The first surface 231a may be slightly lower than or slightly higher than or flush with the connection surface 221a, and the height difference between the two may be within the allowable machining error range.

[0170] Controlling the height difference between the first surface 231a and the connection surface 221a within an appropriate error range can enable the pressing member S to press the tab 32 more flatly against the connection surface 221a, improving the connection reliability.

[0171] In some embodiments, the thickness of the first surface 231a along the length direction Z of the first housing wall and / or the width direction Y of the first housing wall is greater than or equal to 1 mm and less than or equal to 3 mm.

[0172] In the prior art, the thickness of the positioning portion 231 is generally less than 1 mm, only serving to position the first connection portion 221. The positioning portion 231 in the embodiments of the present application not only serves to position the first connection portion 221, but also has the function of supporting the pressing member S. Thus, the pressing member S can press the tab 32 more closely against the first connection portion 221, facilitating subsequent welding, reducing the risk of false soldering, and improving the connection reliability.

[0173] In some embodiments, the electrode terminal 22 further includes a second connection portion 222 located outside the housing 10 along the thickness direction X of the first housing wall, and the second connection portion 222 is connected to the first connection portion 221. The second connection portion 222 can be riveted to the first connection portion 221 or the two are configured as an integral structure.

[0174] The second connection portion 222 can be used to connect an external busbar component. Through the busbar component, a plurality of battery cells 1 can be connected together to form a battery module, improving the capacity of the battery and meeting the high-power power consumption requirements.

[0175] In some embodiments, the electrode terminal 22 includes a terminal plate 2221 and a terminal disc 2211 connected to each other. The first connection portion 221 includes the terminal disc 2211, and the terminal disc 2211 includes a connection surface 221a. The terminal plate 2221 and the terminal disc 2211 can be connected by riveting or are of an integral structure.

[0176] The terminal disc 2211 is in a disc shape, such as a circular disc shape or an oval shape, etc., and its material can be a conductive metal such as copper, iron, aluminum, stainless steel, aluminum alloy, etc.

[0177] The terminal disc 2211 includes a connection surface 221a, and the connection surface 221a is substantially a plane, so that the connection surface 221a fits more closely with the tab 32, facilitating subsequent connection and improving connection reliability.

[0178] In some embodiments, the second connection portion 222 includes a terminal plate 2221.

[0179] The terminal plate 2221 is in a plate shape and has a plane that can be used to connect to the busbar component. The shape of the terminal plate 2221 can be circular, square or other shapes. The material of the terminal plate 2221 can be the same as or different from the material of the terminal disc 2211.

[0180] The second connection portion 222 includes the terminal plate 2221, so that the connection surface 221a fits more closely with the busbar component, facilitating subsequent connection and improving connection reliability.

[0181] In some embodiments, the positioning portion 231 has a second surface 231b, and the second surface 231b is disposed around the outer periphery of the first connection portion 221 and contacts the outer peripheral surface of the first connection portion 221.

[0182] The shape of the positioning portion 231 can be adapted to the shape of the first connection portion 221. Since the positioning portion 231 is flush with the first connection portion 221 along the thickness direction of the first housing wall 12, the positioning portion 231 more firmly encloses the first connection portion 221 therein, improving the positioning stability and reducing the risk of shaking during the connection (such as welding) between the tab 32 and the first connection portion 221, which is beneficial to connection reliability.

[0183] In some embodiments, the insulating member 23 further includes a portion 232 located between the first connecting portion 221 and the first outer shell wall 12 along the thickness direction X of the first outer shell wall. Figure 10 as shown.

[0184] The portion 232 located between the first connecting portion 221 and the first outer shell wall 12 is used to isolate the first connecting portion 221 from the first outer shell wall 12, reducing the risk of short circuit. It can be understood that the portion 232 located between the first connecting portion 221 and the first outer shell wall 12 has a through hole for the first connecting portion 221 to pass through.

[0185] In some embodiments, the insulating member 23 further includes a protruding portion 233 protruding toward the electrode assembly 30 along the thickness direction X of the first outer shell wall.

[0186] The protruding portion 233 can be used to abut against the main body portion 31 of the electrode assembly 30, reducing the risk of shaking of the electrode assembly 30.

[0187] Exemplarily, an explosion-proof valve and a liquid injection hole are further provided on the first outer shell wall 12 (such as an end cap). The insulating member 23 includes an insulating body, and an explosion-proof valve avoidance hole 234 corresponding to the explosion-proof valve and a liquid injection avoidance hole 235 corresponding to the liquid injection hole are provided on the insulating body.

[0188] Next, refer to Figures 3 to 11 to illustrate specific examples of embodiments of the present application.

[0189] The battery cell 1 of the embodiment of the present application includes a housing 10, an electrode terminal 22, and an electrode assembly 30.

[0190] The housing 10 includes a plurality of outer shell walls, among which the first outer shell wall 12 is included. The remaining outer shell walls enclose a housing 11 with an opening. The first outer shell wall 12 can be an end cap of the battery cell 1, and the first outer shell wall 12 closes the opening so that the housing 11 and the first outer shell wall 12 form an accommodation space A for accommodating the electrode assembly 30.

[0191] Refer to Figures 8 to 11 , the electrode terminal 22 is disposed on the first outer shell wall 12. An insulating member 23 is disposed between the first outer shell wall 12 and the housing 11. The electrode terminal 22 includes a first connecting portion 221 that passes through the first outer shell wall 12 and protrudes from the first outer shell wall 12 along its thickness direction X close to the electrode assembly 30 Figure 3 as shown, and a second connecting portion 222 that protrudes from the first outer shell wall 12 along its thickness direction X away from the electrode assembly 30. The second connecting portion 222 is riveted to the first connecting portion 221.

[0192] The insulating member 23 includes a portion protruding from the first outer shell wall 12 along its thickness direction X close to the electrode assembly 30Figure 1 The positioning portion 231 on one side (as shown) is disposed around the outer periphery of the first connecting portion 221 and functions to position the first connecting portion 221. The positioning portion 231 has a first surface 231a approaching the electrode assembly 30 along the thickness direction X of the first housing wall. The first connecting portion 221 has a connecting surface 221a approaching the electrode assembly 30 along the thickness direction X of the first housing wall, and the first surface 231a is flush with the connecting surface 221a. Specifically, the height by which the first connecting portion 221 protrudes from the first housing wall 12 is H 1 and the height by which the positioning portion 231 protrudes from the first housing wall 12 is H 2 , H 1 and the difference between H 2 is in the range of 0 mm to 0.3 mm. The first connecting portion 221 is directly welded to the tab 32 of the electrode assembly 30 through the connecting surface 221a. During the connection process between the tab 32 and the first connecting portion 221, the first surface 231a is used to support the pressing member S so that the pressing member S presses the tab 32 against the connecting surface 221a of the first connecting portion 221.

[0193] See Figures 3 to 5 , each electrode assembly 30 includes a main body portion 31 and two tabs 32 disposed on the main body portion 31 and respectively extending from the same end of the main body portion 31. Each tab 32 includes a plurality of tab pieces 32a. The tab 32 has a connecting portion 321 and a converging portion 322. The connecting portion 321 is connected between the main body portion 31 and the converging portion 322. The converging portion 322 is ultrasonically welded together via a plurality of tab pieces 32a to form a compact and integral plate-like structure, and an ultrasonic weld mark is formed on the converging portion 322. Along the layer thickness direction X of the converging portion 322, there is an overlapping portion between the converging portion 322 and the electrode terminal 22. The connecting surface 221a of the converging portion 322 and the electrode terminal 22 is directly connected by laser welding, and a laser weld mark is formed on the converging portion 322 ( Figure 4 the second welded connecting portion 322b shown), wherein the laser weld mark coincides with the ultrasonic weld mark, the converging portion 322 is bent relative to the connecting portion 321, and the main body portions 31 of the two electrode assemblies 30 are arranged face to face along the thickness direction Y ( Figure 3 shown).

[0194] First, multiple tab pieces 32a of each electrode assembly 30 are brought closer to the same position and stacked together by an ultrasonic welding device to form a tab 32 having a converging portion 322 and a connecting portion 321, such that the converging portion 322 is configured as a compact integral plate-like structure, and ultrasonic welding imprints are formed on the converging portion 322; then, the compact converging portion 322 in the electrode assembly 30 is stacked on the connecting surface 221a of the first connecting portion 221 of each electrode terminal 22 along the layer thickness direction X; next, the converging portion 322 is pressed onto the connecting surface 221a by an annular pressing member S, and the pressing member S is supported jointly by the connecting surface 221a and the first surface 231a, so that the converging portion 322 is in fit with the connecting surface 221a; thereafter, the welding head extends into the pressing member S and performs laser welding at the ultrasonic welding imprint position of the converging portion 322 to weld the converging portion 322 and the connecting surface 221a together, completing the welding operation of the tab 32 of the electrode assembly 30 and the electrode terminal 22. After that, the pressing member S is removed, and the two main body portions 31 are respectively rotated 90 degrees in the direction approaching each other, so that they are arranged face to face along the thickness direction ( Figure 3 as shown), so that the converging portion 322 is bent relative to the connecting portion 321, and then, the two electrode assemblies 30 are placed into the housing 10 and the first housing wall 12 closes the opening of the housing 10.

[0195] This application also provides a battery 100, which includes a box body 2 and at least one battery cell 1 mentioned above.

[0196] Referring to Figure 2 , the box body 2 includes a lower box body 3 and an upper box body 4, and the lower box body 3 and the upper box body 4 are covered with each other to form a receiving space for the battery cell 1.

[0197] This application also provides an electrical device, and the electrical device includes the battery cell 1 or the battery 100 mentioned above for providing electric energy.

[0198] This application also provides an energy storage device, which includes the battery cell 1 or the battery 100 mentioned above for providing electric energy, and the battery cell 1 can store electric energy and can provide electric energy.

[0199] The energy storage device can be an energy storage box or an energy storage cabinet. The energy storage cabinet includes a plurality of battery compartments for accommodating the battery cell 1. In addition, the energy storage cabinet can also include a thermal management component, a power control component, etc.

[0200] The above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit it; 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 on some 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 all be covered within the scope of the present application. In particular, as long as there is no structural conflict, the 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 falling within the scope of the present application.

Claims

1. A battery cell, characterized in that: include: A housing having a receiving space; An electrode terminal, disposed on the housing; At least one electrode assembly is disposed in the accommodating space, wherein the electrode assembly comprises a main body and a pole ear disposed on the main body, wherein the pole ear comprises a plurality of pole ear sheets, and the pole ear is directly connected to the electrode terminal.

2. The battery cell according to claim 1, characterized in that: The electrode tab has a connecting portion and a gathering portion, wherein the connecting portion is connected between the main body portion and the gathering portion, the gathering portion is formed by stacking and connecting a plurality of the electrode tab sheets, and the gathering portion is directly connected to the electrode terminal.

3. The battery cell according to claim 2, characterized in that: A first welding connection portion is formed on the gathered portion, and a plurality of the pole tabs are connected as one body through the first welding connection portion. The gathered portion and the electrode terminal are connected to each other via a second welding connection portion, and in the same projection plane perpendicular to the thickness direction of the gathered portion, projections of the second welding connection portion and the first welding connection portion have an overlapping portion.

4. The battery cell according to claim 3, characterized in that: In the same projection plane perpendicular to the thickness direction of the gathered portion, the projection of the second welding connection portion does not exceed the projection of the first welding connection portion.

5. The battery cell according to claim 4, characterized in that: The projection of the second weld connection has an area of ​​30% to 100% of the projection of the first weld connection.

6. The battery cell according to any one of claims 2 to 5, characterized in that: The gathered portion is configured as a plate-shaped structure.

7. The battery cell according to any one of claims 2 to 5, characterized in that: One end of the connecting portion connected to the gathering portion is located at the center of the main body in the thickness direction.

8. The battery cell according to any one of claims 2 to 5, characterized in that: The electrode terminal includes a positive terminal and a negative terminal; The tabs include a positive tab and a negative tab, the positive tab and the negative tab are respectively arranged at the same end of the main body, the positive tab is directly connected to the positive terminal, and the negative tab is directly connected to the negative terminal.

9. The battery cell according to claim 8, characterized in that: Two electrode assemblies are provided, and the electrode tabs of the two electrode assemblies with the same polarity are electrically connected, and the electrode tabs of each electrode assembly are directly connected to the same electrode terminal through their respective retracted parts.

10. The battery cell according to claim 9, characterized in that: The two electrode assemblies are arranged opposite to each other along the thickness direction of the main body.

11. A battery, characterized in that: include: Box; At least one battery cell according to any one of claims 1 to 10, wherein the battery cell is disposed in the casing.

12. An electrical device, characterized in that: The electrical device comprises the battery cell according to any one of claims 1 to 10 or the battery according to claim 11, and the battery can provide electrical energy for the electrical device.

13. An energy storage device, characterized in that: The invention comprises the battery cell according to any one of claims 1 to 10 or the battery according to claim 11, wherein the battery is capable of storing electric energy and providing electric energy.

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