Battery monomer, battery device and electric device

Abstract

The utility model provides a battery monomer, a battery device and a power utilization device, the battery monomer comprises a shell, an electrode assembly, an electrode terminal and a sealing piece, and the shell is provided with an accommodating cavity; the electrode assembly is arranged in the accommodating cavity, the electrode assembly comprises an electrode main body and a tab, and the tab extends out of the electrode main body; the electrode terminal and the tab are arranged in an overlapping manner to form an overlapping part, and the overlapping part is provided with a welding printing area; and the sealing element is at least connected between the overlapping part and the shell in a sealing manner and covers the welding printing area. The sealing piece and the shell can provide binding force for the tabs, so that the connection strength of the tabs is improved; the sealing piece can provide sealing for the overlapping part on the outer surface of the joint of the sealing piece and the overlapping part, lithium precipitation of the tab is reduced, and the service life of the tab is prolonged; the sealing piece covers the welding mark area, and a welding mark protection adhesive tape does not need to be introduced to cause weight burden; the sealing piece is connected between the shell and the overlapping part and can assist in sealing the shell, and the sealing performance of the shell is improved.

Description

Technical Field

[0001] This application relates to the field of battery technology, and in particular to a battery cell, a battery device, and an electrical device. Background Technology

[0002] With the development of new energy technologies, batteries are being used more and more widely, such as in mobile phones, laptops, electric vehicles, electric cars, electric airplanes, electric ships, electric toy cars, electric toy ships, electric toy airplanes, and power tools.

[0003] The thickness of the battery changes repeatedly during charging and discharging, causing repeated stress on the tabs, which can easily damage them. Utility Model Content

[0004] In view of the above problems, this application provides a battery cell, a battery device and an electrical device, wherein the battery cell is beneficial to improving the connection strength of the tabs.

[0005] In a first aspect, this application provides a battery cell, the battery cell including a housing, an electrode assembly, electrode terminals, and a seal; the housing has a receiving cavity; the electrode assembly is disposed in the receiving cavity, the electrode assembly including an electrode body and a tab, the tab extending from the electrode body; the electrode terminal and the tab are overlapped to form an overlap portion, the overlap portion having a solder area; the seal is at least sealingly connected between the overlap portion and the housing, and covers the solder area.

[0006] In the technical solution of this application embodiment, the sealing element is at least sealed between the overlapping portion and the outer shell. The sealing element is connected to the outside of the overlapping portion, and the outer shell is connected to the outside of the sealing element. Both the sealing element and the outer shell can provide binding force, making the stacked tabs fit together, thereby improving the connection strength of the tabs and reducing the cracking and detachment of the solder. The sealing element is connected to the outer surface of the overlapping portion, which can provide a seal for the outer surface of the overlapping portion at the connection, reducing the infiltration of electrolyte between the tabs, reducing lithium plating on the tabs, and improving the service life of the tabs, thereby improving the reliability and service life of the battery cell. The sealing element covers the solder area, which can reduce the damage caused by burrs, particles, etc. that may exist in the solder area. There is no need to introduce additional solder protection tape, which will not burden the weight of the battery cell and can improve the energy density of the battery cell. As a connection medium between the overlapping portion and the outer shell, the sealing element connects between the outer shell and the overlapping portion, which can assist the outer shell in sealing and improve the sealing performance of the outer shell.

[0007] In some embodiments, the seal includes a large face portion and side face portions, with two opposing large face portions connected by two side face portions. The large face portion at least covers the large face portion of the overlapping portion, and the side face portions at least cover the side face portion of the overlapping portion. When the side face portions cover the side face portion of the overlapping portion, they can provide a binding force in the tab thickness direction, improving the connection strength of the tab. The connection between the two large face portions and the two side face portions of the seal can improve the structural strength of the seal and increase the binding force of the seal on the tab.

[0008] In some embodiments, the thickness of the large portion ranges from 0.15 mm to 0.25 mm, which can reduce the weight burden on the battery cell when providing protection for the solder area, thereby reducing the impact on the energy density of the battery cell; the thickness of the side portion ranges from 3 mm to 5 mm, which can improve the connection strength between the side portion and the tabs and electrode terminals, thereby improving the binding force on the tabs, and can also improve the connection strength between the side portion and the housing, thereby improving the sealing performance.

[0009] In some embodiments, the thickness of the side portion gradually decreases at the end facing the electrode body in the extending direction of the tab, which can eliminate or partially eliminate the risk of the sealing material sticking to the electrode body and improve the controllability of the production process.

[0010] In some embodiments, in the extension direction of the tab, the distance between the two sides of the solder area is smaller than the distance between the two sides of the overlapping portion, which can reduce the requirements for welding accuracy, reduce the stress at the two edges of the overlapping portion in the extension direction of the tab, and improve the connection strength of the tab.

[0011] In some embodiments, in the extending direction of the tab, the seal includes a first end and a second end opposite to each other. The first end is located between the solder area and the electrode body, and the second end is located between the free end of the electrode terminal and the solder area. The seal can seal the solder area on the overlapping portion, improving the connection strength and service life of the tab. The distance between the first end and the solder area is smaller than the distance between the second end and the solder area, which can seal the solder area within the opening of the housing, reducing the risk of exposure of the solder area.

[0012] In some embodiments, the first end is located between the overlapping portion and the electrode body, and the second end is located between the free end of the electrode terminal and the overlapping portion. The seal can seal the entire overlapping portion, further improving the binding force and sealing performance, thereby improving the connection strength and service life of the electrode tab.

[0013] In some embodiments, the distance between the first end and the electrode body is L1, and the distance between the first end and the overlapping portion is L2. The ratio of L1 to L2 is in the range of 1:2 to 1:1, which can increase the proportion of the electrode tab covered by the seal between the overlapping portion and the electrode body, thereby improving the connection strength and service life of the electrode tab.

[0014] In some embodiments, the distance between the first end and the electrode body is not less than 0.5 mm, which allows for allowance for systematic errors such as assembly errors and processing errors, and reduces the potential risk of the electrode body being damaged due to interference; the distance between the first end and the overlapping portion is not less than 1 mm, which allows for allowance for systematic errors such as assembly errors and processing errors, and ensures that the seal completely covers the overlapping portion.

[0015] In some embodiments, the distance between the second end and the overlapping portion is L3, and the distance between the second end and the free end of the electrode terminal is L4. The ratio of L3 to L4 is in the range of 1:3 to 3:4, which can increase the length of the electrode terminal outside the housing, making it easier for the electrode terminal to be connected to the battery device and the power device.

[0016] In some embodiments, the distance between the second end and the soldering area is not less than 20mm, which can increase the distance between the soldering area and the casing seal, and reduce the impact of external forces on the battery cell on the tab.

[0017] In some embodiments, the distance between the second end and the free end of the electrode terminal is in the range of 25mm to 35mm, which can take into account both the structural strength of the electrode terminal and the connection strength of the tab, thereby improving the reliability of the battery cell.

[0018] Secondly, this application provides a battery device that includes the battery cell described in the above embodiments.

[0019] Thirdly, this application provides an electrical device that includes the battery device described in the above embodiments, the battery device being used to provide electrical energy.

[0020] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, the following are specific embodiments of this application. Attached Figure Description

[0021] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the scope of this application. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings:

[0022] Figure 1 This is a simplified schematic diagram of a vehicle according to some embodiments of this application;

[0023] Figure 2 This is a split schematic diagram of a battery device according to some embodiments of this application;

[0024] Figure 3 This is a schematic diagram of the structure of a battery cell in some embodiments of this application. Figure 1 ;

[0025] Figure 4 This is a schematic diagram of the structure of a battery cell in some embodiments of this application. Figure 2 ;

[0026] Figure 5 For the purposes of this application Figure 3 A schematic diagram of the structure of a single battery cell after removing its outer casing;

[0027] Figure 6 For the purposes of this application Figure 5 Cross-sectional schematic diagram of the overlapping section and the seal;

[0028] Figure 7 For the purposes of this application Figure 5 A magnified view of a portion at point I;

[0029] Figure 8 This is a schematic diagram of the welding of electrode assemblies and electrode terminals in some embodiments of this application;

[0030] Figure 9 For the purposes of this application Figure 8 Schematic diagram of the overlapping section;

[0031] Figure 10 This is a schematic diagram of the structure of an electrode assembly according to some embodiments of this application.

[0032] The reference numerals in the detailed embodiments are as follows:

[0033] 1000 - Vehicle; 100 - Battery unit; 200 - Controller; 300 - Motor;

[0034] 10-Battery module; 11-Box; 111-First box; 112-Second box; 1-Battery cell;

[0035] 2-Electrode terminal; 3-Housing shell; 4-Seal; 41-Side part; 42-Large part; 43-First end; 44-Second end; 5-Electrode assembly; 51-Electrode body; 52-Electrode tab; 6-Overlapping part; 61-Soldering area. Detailed Implementation

[0036] The embodiments of the technical solution of this application will now be described in detail with reference to the accompanying drawings. These embodiments are only used to more clearly illustrate the technical solution of this application and are therefore merely examples, and should not be used to limit the scope of protection of this application.

[0037] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms “comprising” and “having”, and any variations thereof, in the specification, claims, and foregoing description of the drawings are intended to cover non-exclusive inclusion.

[0038] In the description of the embodiments of this application, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly defined.

[0039] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0040] In the description of the embodiments in this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.

[0041] In the description of the embodiments of this application, the term "multiple" refers to two or more (including two), similarly, "multiple groups" refers to two or more (including two groups), and "multiple pieces" refers to two or more (including two pieces).

[0042] In the description of the embodiments of this application, the technical terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of this application and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of this application.

[0043] In the description of the embodiments of this application, unless otherwise expressly specified and limited, technical terms such as "installation," "connection," "joining," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. For those skilled in the art, the specific meaning of the above terms in the embodiments of this application can be understood according to the specific circumstances.

[0044] Currently, judging from market trends, the application of power batteries is becoming increasingly widespread. Power batteries are not only used in energy storage systems such as hydropower, thermal power, wind power, and solar power plants, but also extensively used in electric vehicles such as electric bicycles, electric motorcycles, and electric cars, as well as in military equipment and aerospace. With the continuous expansion of power battery applications, market demand is also constantly increasing.

[0045] A pouch battery is a type of battery with a flexible casing. In the event of thermal runaway, it typically bulges or cracks at the seal to release heat. Compared to hard-shell batteries, it carries less risk and has a variety of applications.

[0046] In the manufacturing process of pouch batteries, the tabs (positive tabs extending from the positive electrode and negative tabs extending from the negative electrode) of the electrode assembly (e.g., formed by stacking positive electrode sheets, separators, and negative electrode sheets) need to be soldered to the electrode terminals (forming a solder area at the solder joint, which includes one or more solder marks). Then, the battery is encapsulated and undergoes processes such as electrolyte injection and formation to become the finished battery. In rechargeable pouch batteries, lithium deposits on the negative electrode during charging, increasing the battery thickness. During discharging, lithium is stripped from the negative electrode, reducing the battery thickness. As the rechargeable pouch battery cycles through charging and discharging, the tabs are repeatedly subjected to stress due to changes in battery thickness, making them prone to fatigue failure, leading to cracking and detachment at the solder joints. Furthermore, the free electrolyte on the tabs can cause lithium deposition, which can easily damage the tabs.

[0047] In related technologies, sealant is applied to the electrode terminals of pouch batteries. The soldering area is located between the sealant area and the electrode body. During pouch battery encapsulation, the sealant is connected to the outer casing (e.g., an aluminum-plastic bag) via heat fusion, thereby achieving a seal at the electrode terminals. Protection of the soldering area is typically achieved by applying soldering protective tape to the surface of the soldering area.

[0048] However, while solder protective tape can protect the surface of the solder area, it doesn't provide any force between the stacked tabs. This means it cannot mitigate the repeated stretching of the tabs during battery cycling, potentially leading to cracking and detachment. Furthermore, the lack of effective sealing between adjacent tabs in the solder area allows electrolyte infiltration and lithium deposition. Under stress-free conditions, lithium deposition at the tabs can easily lead to pulverization and short-circuit risks. Additionally, solder protective tape typically consists of a substrate and an adhesive layer, significantly impacting the weight of the pouch battery. Introducing solder protective tape reduces the battery's energy density, and it can also be incompatible with the electrolyte.

[0049] To improve the connection strength of the tabs, extend their service life, and reduce the impact on the energy density of the pouch battery, the overlapping portion formed by the overlap between the electrode terminals and the tabs can be sealed and its connection strength strengthened.

[0050] Based on the above considerations, this application provides a battery cell, which includes a casing, an electrode assembly, electrode terminals, and a seal. The electrode assembly includes an electrode body and a tab. The tab and the electrode terminal are overlapped to form an overlap portion. The overlap portion is welded to form a solder area. The solder area includes multiple solder marks to realize the connection between adjacent tabs and the connection between the tab and the electrode terminal. The seal is at least sealed between the overlap portion and the casing and covers the solder area.

[0051] In this type of battery cell, the overlapping portion has a surface with solder markings, and the other surface opposite to this surface (the two large surfaces of the overlapping portion), as well as the two surfaces connected to this surface (the two side surfaces of the overlapping portion), are all connected to sealants and sealed at the connection points. The sealants can apply force in the overlapping direction of the tabs and electrode terminals, binding the multiple stacked tabs together, making the multi-layered tabs fit together, thereby distributing some of the tensile force, reducing the tensile force on the solder markings, and improving the connection strength of the tabs. Furthermore, when the sealants are connected to the two side surfaces of the overlapping portion, they also provide a sealing effect at the connection points, reducing lithium deposition of electrolyte between the tabs and improving the lifespan of the tabs. In addition, the sealants are also connected to the outer casing, not only assisting in sealing the casing but also providing support to the outer periphery of the overlapping portion, further improving the connection strength of the tabs and extending their lifespan, thereby improving the reliability and lifespan of the battery cell.

[0052] The battery cells disclosed in this application can be used, but are not limited to, in electrical devices such as vehicles, ships, or aircraft. A power system for such an electrical device can be constructed using battery cells and battery devices disclosed in this application, which helps to improve the reliability and service life of the electrical device.

[0053] This application provides an electrical device that uses a battery as a power source. The electrical device can be, but is not limited to, mobile phones, tablets, laptops, electric toys, power tools, electric vehicles, electric cars, ships, spacecraft, etc. Electric toys can include stationary or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, etc. Spacecraft can include airplanes, rockets, space shuttles, and spacecraft, etc.

[0054] For ease of explanation, the following embodiments will use a vehicle as an example of an electrical device according to an embodiment of this application.

[0055] Please refer to Figure 1 , Figure 1 This is a simplified schematic diagram of a vehicle according to some embodiments of this application.

[0056] Vehicle 1000 can be a gasoline-powered vehicle, a natural gas-powered vehicle, or a new energy vehicle. New energy vehicles can be pure electric vehicles, hybrid electric vehicles, or range-extended electric vehicles, etc. A battery device 100 is installed inside vehicle 1000, which can be located at the bottom, front, or rear of vehicle 1000. The battery device 100 can be used to power vehicle 1000; for example, it can serve as the operating power source for vehicle 1000. Vehicle 1000 may also include a controller 200 and a motor 300. The controller 200 controls the battery device 100 to supply power to the motor 300, for example, to meet the power needs of vehicle 1000 during starting, navigation, and driving.

[0057] In some embodiments of this application, the battery device 100 can not only serve as the operating power source for the vehicle 1000, but also as the driving power source for the vehicle 1000, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1000.

[0058] Please refer to Figure 2 , Figure 2 This is a split schematic diagram of a battery device according to some embodiments of this application.

[0059] The battery device 100 includes a housing 11 and individual battery cells, with the individual battery cells housed within the housing 11. The housing 11 provides a space for the individual battery cells and can have various structures. In some embodiments, the housing 11 may include a first housing 111 and a second housing 112, which overlap each other, collectively defining a space for accommodating the individual battery cells. The second housing 112 may be a hollow structure with one open end, while the first housing 111 may be a plate-like structure, covering the open side of the second housing 112 so that the first housing 111 and the second housing 112 together define the space. Alternatively, both the first housing 111 and the second housing 112 may be hollow structures with one open end, with the open side of the first housing 111 covering the open side of the second housing 112. Of course, the box formed by the first box 111 and the second box 112 can be of various shapes, such as a cylinder, a cuboid, etc.

[0060] In the battery device 100, there can be multiple battery cells, which can be connected in series, parallel, or in a mixed configuration. A mixed configuration means that multiple battery cells are connected in both series and parallel connections. Multiple battery cells can be directly connected in series, parallel, or in a mixed configuration, and then the entire assembly of the multiple battery cells is housed within a casing. Alternatively, the battery device 100 can also consist of multiple battery cells first connected in series, parallel, or in a mixed configuration to form a battery module 10, and then multiple battery modules 10 connected in series, parallel, or in a mixed configuration to form a whole, which is then housed within a casing. The battery device 100 may also include other structures; for example, it may include a busbar component for electrical connection between multiple battery cells.

[0061] Each battery cell can be a rechargeable battery; the battery cell can be a pouch battery, such as a lithium metal rechargeable pouch battery or a silicon-carbon rechargeable pouch battery.

[0062] Please refer to Figure 3 and Figure 4 , Figure 3 This is a schematic diagram of the structure of a battery cell in some embodiments of this application. Figure 1 ; Figure 4 This is a schematic diagram of the structure of a battery cell in some embodiments of this application. Figure 2 .

[0063] A battery cell 1 refers to the smallest unit that makes up the battery device 100. A battery cell 1 includes a casing 3, electrode terminals 2, electrode assemblies, and other functional components.

[0064] The outer casing 3 is used to seal the battery cell 1 and forms the internal environment of the battery cell 1. The formed internal environment can accommodate electrode components, electrolyte, and other components. The outer casing 3 can be made of aluminum-plastic film, plastic, etc.

[0065] The electrode assembly is the component in the battery cell 1 where electrochemical reactions occur. The electrode assembly is mainly formed by stacking electrode plates (positive and negative electrodes), and typically a separator is provided between the positive and negative electrodes. The active material portions of the positive and negative electrodes constitute the electrode body of the electrode assembly, while the non-active material portions extending from the positive and negative electrodes constitute the positive and negative electrode tabs, respectively. During the charging and discharging process of the battery device 100, the positive and negative active materials react with the electrolyte, and the positive and negative electrode tabs are respectively connected to the electrode terminals 2 to form a current loop, outputting or inputting electrical energy from the battery cell 1.

[0066] The positive electrode sheet may include a positive current collector and a positive active material disposed on at least one surface of the positive current collector. The positive current collector may be an aluminum foil current collector or a modified aluminum foil current collector. The positive active material may include at least one of the following materials: lithium transition metal oxides and / or lithium phosphates with an olivine structure. The lithium transition metal oxide may be lithium cobalt oxide, lithium nickel oxide, lithium manganese oxide, lithium nickel manganese oxide, lithium nickel cobalt manganese oxide, lithium nickel cobalt aluminum oxide, or a combination thereof.

[0067] For example, lithium transition metal oxides may include, but are not limited to, lithium cobalt oxides (such as LiCoO2), lithium nickel oxides (such as LiNiO2), lithium manganese oxides (such as LiMnO2, LiMn2O4), lithium nickel cobalt oxides, lithium manganese cobalt oxides, lithium nickel manganese oxides, and lithium nickel cobalt manganese oxides (such as LiNi). 1 / 3 Co 1 / 3 Mn 1 / 3 O2 (also known as NCM) 333 LiNi 0.5 Co 0.2 Mn 0.3 O2 (also known as NCM) 523 LiNi 0.5 Co 0.25 Mn 0.25 O2 (also known as NCM) 211 LiNi 0.6 Co 0.2 Mn 0.2 O2 (also known as NCM) 622 LiNi 0.8 Co 0.1 Mn 0.1 O2 (also known as NCM) 811 LiNi 0.96 Co 0.02 Mn 0.02 O2 (also known as Ni) 96), lithium nickel cobalt aluminum oxide (such as LiNi) 0.85 Co 0.15 Al 0.05 At least one of O2 and its modified compounds.

[0068] For example, the lithium phosphate with olivine structure may include, but is not limited to, at least one of lithium iron phosphate (such as LiFePO4 (also referred to as LFP)), lithium iron phosphate and carbon composites, lithium manganese phosphate (such as LiMnPO4), lithium manganese phosphate and carbon composites, lithium manganese iron phosphate, and lithium manganese iron phosphate and carbon composites.

[0069] The negative electrode sheet may include a negative electrode current collector and a negative electrode active material disposed on at least one surface of the negative electrode current collector. The negative electrode current collector may be a copper foil current collector or a modified copper foil current collector. The negative electrode active material may be metallic lithium or elemental silicon, or a silicon carbide compound, or an alloy formed by metallic lithium and other various metallic or non-metallic elements.

[0070] For example, metallic elements may include, but are not limited to, tin (Sn), zinc (Zn), aluminum (Al), magnesium (Mg), silver (Ag), gold (Au), gallium (Ga), indium (In), and tin foil (Pt). Non-metallic elements may include, but are not limited to, boron (B), carbon (C), and silicon (Si).

[0071] The base membrane of the separator (separation membrane) can be, but is not limited to, polyethylene porous membrane, polypropylene porous membrane, polyimide porous membrane, and porous membranes formed by a combination of various polymers.

[0072] Electrolytes can be, but are not limited to, lithium-ion electrolytes, ester electrolytes, ether electrolytes, etc.

[0073] Please refer to Figures 5 to 10 , Figure 5 For the purposes of this application Figure 3 A schematic diagram of the structure of a single battery cell after removing its outer casing; Figure 6 For the purposes of this application Figure 5 Cross-sectional schematic diagram of the overlapping section and the seal; Figure 7 For the purposes of this application Figure 5 A magnified view of a portion at point I; Figure 8 This is a schematic diagram of the welding of electrode assemblies and electrode terminals in some embodiments of this application; Figure 9 For the purposes of this application Figure 8 Schematic diagram of the overlapping section; Figure 10 This is a schematic diagram of the structure of an electrode assembly according to some embodiments of this application.

[0074] like Figure 3 , Figure 5 , Figures 8 to 10As shown, according to some embodiments of this application, this application provides a battery cell 1, which includes a housing 3, an electrode assembly 5, an electrode terminal 2, and a sealing member 4; the housing 3 has a receiving cavity; the electrode assembly 5 is disposed in the receiving cavity, and the electrode assembly 5 includes an electrode body 51 and a tab 52, with the tab 52 extending from the electrode body 51; the electrode terminal 2 and the tab 52 are overlapped to form an overlap portion 6, and the overlap portion 6 has a solder area 61; the sealing member 4 is at least sealed between the overlap portion 6 and the housing 3, and covers the solder area 61.

[0075] In electrode assembly 5, electrode body 51 includes multiple stacked positive electrode plates, negative electrode plates, and separators. Each positive electrode plate has a positive electrode tab extending from it, and each negative electrode plate has a negative electrode tab extending from it. All positive electrode tabs are stacked and connected to one electrode terminal 2, and all negative electrode tabs are stacked and connected to one electrode terminal 2, thereby achieving the connection between the tab 52 and the electrode terminal 2. Figure 3 and Figure 4 As shown, the positive electrode tab and the negative electrode tab can extend from the same side of the electrode body 51 or from different sides of the electrode body 51 (for example, the positive electrode tab and the negative electrode tab are located on opposite sides or adjacent sides of the electrode body 51, respectively).

[0076] The following is defined as follows: the direction in which the tab 52 extends from the electrode body 51 is the extension direction of the tab 52 (the length direction of the tab 52); the direction perpendicular to the extension direction of the tab 52 on the large surface of the tab 52 (the two surfaces with the largest surface area of ​​the positive or negative tab, parallel to the large surface of the overlapping part 6) is the width direction of the tab 52; and the direction perpendicular to the large surface of the tab 52 is the thickness direction of the tab 52.

[0077] The electrode terminal 2 is in the form of a sheet. In the extending direction of the electrode tab 52, the electrode terminal 2 overlaps with the electrode tab 52 to form an overlapping portion 6. The overlapping portion 6 forms a solder area 61 by welding (e.g., ultrasonic welding). The solder area 61 includes one or more solder marks and is located on the large surface of the electrode tab 52 (the large surface of the overlapping portion 6).

[0078] like Figure 5 and Figure 7 As shown, in the extending direction of the tab 52, the distance between the two sides of the solder area 61 can be equal to the distance between the two sides of the overlapping portion 6 (that is, welding is performed on the entire large surface of the overlapping portion 6), and the distance between the two sides of the solder area 61 can also be less than the distance between the two sides of the overlapping portion 6 (that is, welding is performed on a part of the large surface of the overlapping portion 6).

[0079] When forming the overlapping portion 6, all the tabs 52 (positive or negative) can be stacked and pressed together, and then connected to the electrode terminal 2 on one side of the thickness direction of the tabs 52; or the electrode terminal 2 can be inserted between the stacked tabs 52.

[0080] like Figure 6 As shown, when the seal 4 is sealed to the overlapping portion 6, the seal 4 covers the outer surface of the overlapping portion 6. During connection, the seal 4 covers at least two large surfaces and a portion of each of the two side surfaces of the overlapping portion 6, and completely covers the solder area 61, providing a seal to the overlapping portion 6 at the covered areas. The portions of the seal 4 connecting to the two large surfaces of the overlapping portion 6 and the portions connecting to the two side surfaces of the overlapping portion 6 can be connected together or not.

[0081] like Figure 7 As shown, in the extending direction of the tab 52, the seal 4 can cover a portion of the outer surface of the overlapping portion 6, or cover the entire outer surface of the overlapping portion 6, or extend beyond the overlapping portion 6 to cover a portion of the outer surface of the electrode terminal 2 and / or the tab 52, providing binding force and sealing to the covered portion of the electrode terminal 2 and / or the tab 52.

[0082] The sealing element 4 is sealed to the housing 3. When the housing 3 is sealed, the sealing element 4 is located outside the overlapping portion 6, and the housing 3 is located outside the sealing element 4. Exemplarily, the sealing element 4 can be heat-fused when it is connected to the overlapping portion 6 (which may also include a portion of the tab 52 and / or electrode terminal 2 adjacent to the overlapping portion 6), and the sealing element 4 can be heat-fused when it is connected to the housing 3, thereby achieving the sealing of the housing 3 at the electrode terminal 2.

[0083] For example, the material of the seal 4 can be hot melt adhesive, such as PP adhesive, and the housing 3 can be made of aluminum-plastic film. Since the seal 4 is made of hot melt adhesive, after the electrode terminal 2 is welded to the tab 52, the seal 4 can be cured at least on the outer surface of the overlapping portion 6, providing a seal and improving the connection strength of the tab 52. When sealing the housing 3, the seal 4 can be hot-melted with the aluminum-plastic film after reaching its phase change melting point, thus sealing the aluminum-plastic film at the electrode terminal 2.

[0084] In the technical solution of this application embodiment, the sealing member 4 is at least sealed between the overlapping portion 6 and the outer shell 3. The sealing member 4 is connected to the outside of the overlapping portion 6, and the outer shell 3 is connected to the outside of the sealing member 4. Both the sealing member 4 and the outer shell 3 can provide binding force to make the stacked tabs 52 fit together, thereby improving the connection strength of the tabs 52. The sealing member 4 is connected to the outer surface of the overlapping portion 6, which can provide a seal for the outer surface of the overlapping portion 6 at the connection point, reduce the infiltration of electrolyte between the tabs 52, reduce lithium plating in the tabs 52, and improve the service life of the tabs 52, thereby improving the reliability and service life of the battery cell 1.

[0085] Furthermore, the seal 4 covers the solder area 61, forming a protective layer on its surface and reducing damage from burrs, particles, etc., that may exist in the solder area 61. This eliminates the need for additional solder protection tape, reducing the weight burden on the battery cell 1 and thus minimizing its impact on energy density. The seal 4 also serves as a connecting medium between the outer casing 3 and the overlapping portion 6, assisting in sealing the outer casing 3 and improving its airtightness.

[0086] like Figure 5 and Figure 6 As shown, according to some embodiments of this application, optionally, the seal 4 includes a large face portion 42 and a side face portion 41, with two opposite large face portions 42 connected by two side face portions 41, the large face portion 42 at least covering the large face of the overlapping portion 6, and the side face portion 41 at least covering the side face of the overlapping portion 6.

[0087] The seal 4 has two large portions 42 and two side portions 41, with the two large portions 42 spaced apart and the two side portions 41 spaced apart. In the width direction of the tab 52, each side of the large portion 42 is connected to a side portion 41, and the seal 4 is integrally formed. Figure 6 As shown, on a plane perpendicular to the extension direction of the tab 52, the outer ring of the seal 4 is a closed polygon.

[0088] In the technical solution of this application embodiment, when the side portion 41 covers the side of the overlapping portion 6, it can provide a binding force in the thickness direction of the tab 52, so that the covered portion of the tab 52 fits together, reducing the tensile force on the solder joint, thereby improving the connection strength of the tab 52. The two large portions 42 of the sealing member 4 are connected to the two side portions 41, and the sealing member 4 surrounds the outside of the overlapping portion 6, which can improve the structural strength of the sealing member 4, thereby increasing the binding force and sealing performance of the sealing member 4 on the tab 52.

[0089] like Figure 6 As shown, according to some embodiments of this application, optionally, the thickness of the large face portion 42 ranges from 0.15 mm to 0.25 mm, and the thickness of the side face portion 41 ranges from 3 mm to 5 mm.

[0090] On the seal 4, the thickness of the side portion 41 is much greater than the thickness of the large portion 42. The thickness of a single large portion 42 can be equal in all areas, resulting in a uniform thickness; or the thickness of a single large portion 42 can be unequal in all areas, resulting in a non-uniform thickness. Two large portions 42 can both be of equal thickness, both be of non-uniform thickness, or one can be of equal thickness while the other is of non-uniform thickness. Similarly, two side portions 41 can both be of equal thickness, both be of non-uniform thickness, or one can be of equal thickness while the other is of non-uniform thickness.

[0091] For example, both large face portions 42 are provided with equal thickness, and both side portions 41 are provided with equal thickness, which can form four planes, making it convenient for the housing 3 to be sealed at the electrode terminal 2.

[0092] For example, the thickness of the side portion 41 can be any value among 3mm, 3.2mm, 3.4mm, 3.6mm, 3.8mm, 4mm, 4.2mm, 4.4mm, 4.6mm, 4.8mm, and 5mm, or any intermediate value between any two adjacent values ​​mentioned above.

[0093] For example, the thickness of the large surface area 42 can be any value among 0.15mm, 0.16mm, 0.17mm, 0.18mm, 0.19mm, 0.2mm, 0.21mm, 0.22mm, 0.23mm, 0.24mm, and 0.25mm, or any intermediate value between any two adjacent values ​​mentioned above.

[0094] In the technical solution of this application embodiment, the thickness of the side portion 41 ranges from 3mm to 5mm, which can improve the connection strength between the side portion 41 and the tab 52 and the electrode terminal 2, thereby increasing the binding force on the tab 52. Furthermore, it can also improve the connection strength between the side portion 41 and the outer casing 3, thereby improving the sealing performance. The thickness of the large portion 42 ranges from 0.15mm to 0.25mm, which can reduce the weight burden on the battery cell 1 when providing protection for the solder area 61, thereby reducing the impact on the energy density of the battery cell 1.

[0095] like Figure 6 and Figure 7 As shown, according to some embodiments of this application, optionally, the thickness of the side portion 41 gradually decreases towards the electrode body 51 in the extending direction of the tab 52.

[0096] In the extending direction of the tab 52, the wall thickness of the side portion 41 gradually increases from the electrode body 51 toward the free end of the electrode terminal 2, and then the thickness remains constant. Visually, the side portion 41 has a chamfer at the end near the electrode body 51.

[0097] In the technical solution of this application embodiment, the thickness of the side portion 41 gradually decreases at the end facing the electrode body 51, which can reduce the amount of material of the side portion 41 at that end. When the seal 4 is connected to the outer shell 3, it is convenient to control the material at that end, eliminate or partially eliminate the hidden danger of the material of the seal 4 sticking to the electrode body 51, and improve the controllability of the production process.

[0098] like Figure 7As shown, according to some embodiments of this application, optionally, in the extending direction of the tab 52, the distance between the two sides of the solder area 61 is less than the distance between the two sides of the overlapping portion 6.

[0099] The solder area 61 occupies a portion of the large surface of the overlapping portion 6, rather than the entire large surface of the overlapping portion 6. In the extending direction of the tab 52, there are gaps between the two sides of the solder area 61 and the two sides of the overlapping portion 6.

[0100] In the technical solution of this application embodiment, the distance between the two sides of the soldering area 61 is smaller than the distance between the two sides of the overlapping portion 6. A gap can be left between the two sides of the soldering area 61 and the two sides of the overlapping portion 6, reducing the requirements for welding accuracy, reducing the stress on both sides of the overlapping portion 6 at the edges in the extension direction of the tab 52, and improving the connection strength of the tab 52.

[0101] like Figure 5 and Figure 7 As shown, according to some embodiments of this application, optionally, in the extending direction of the tab 52, the seal 4 includes a first end 43 and a second end 44 opposite to each other. The first end 43 is located between the solder area 61 and the electrode body 51, and the second end 44 is located between the free end of the electrode terminal 2 and the solder area 61. The distance between the first end 43 and the solder area 61 is less than the distance between the second end 44 and the solder area 61.

[0102] In the extending direction of the tab 52, the seal 4 can completely cover the entire outer surface of the overlapping portion 6 to seal the entire overlapping portion 6; the seal 4 can also cover a portion of the outer surface of the overlapping portion 6 to seal the covered portion of the overlapping portion 6; the seal 4 can also extend toward the free end of the electrode terminal 2 and / or the electrode body 51, covering a portion of the tab 52 and / or a portion of the electrode terminal 2 after extending beyond the overlapping portion 6.

[0103] In the extension direction of the tab 52, taking the two sides of the solder area 61 as references, the distance between the first end 43 and the solder area 61 is smaller, and the distance between the second end 44 and the solder area 61 is larger.

[0104] In the technical solution of this application embodiment, the first end 43 of the sealing member 4 is located between the solder area 61 and the electrode body 51, and the second end 44 is located between the free end of the electrode terminal 2 and the solder area 61. Therefore, the sealing member 4 can seal all solder marks, improving the connection strength and service life of the electrode tab 52. The distance between the first end 43 of the sealing member 4 and the solder area 61 is smaller than the distance between the second end 44 and the solder area 61, which can seal the solder area 61 within the opening of the outer casing 3, reducing the risk of exposure of the solder area 61.

[0105] like Figure 5 and Figure 7As shown, according to some embodiments of this application, optionally, the first end 43 is located between the overlapping portion 6 and the electrode body 51, and the second end 44 is located between the free end of the electrode terminal 2 and the overlapping portion 6.

[0106] In the extending direction of the tab 52, the first end 43 of the seal 4 extends beyond the overlapping portion 6 and toward the electrode body 51, covering a portion of the outer surface of the electrode terminal 2; and the second end 44 of the seal 4 extends beyond the overlapping portion 6 and toward the free end of the electrode terminal 2, covering a portion of the outer surface of the tab 52, providing a seal. In the extending direction of the tab 52, the entire outer surface of the overlapping portion 6 is sealed by the seal 4.

[0107] In the technical solution of this application embodiment, the first end 43 is located between the overlapping portion 6 and the electrode body 51, and the second end 44 is located between the free end of the electrode terminal 2 and the overlapping portion 6. Thus, the sealing member 4 can provide sealing and binding force for the entire overlapping portion 6, and can also provide sealing and binding force for a part of the electrode tab 52 outside the overlapping portion 6 and a part of the electrode terminal 2, thereby further improving the connection strength and service life of the electrode tab 52.

[0108] like Figure 7 As shown, according to some embodiments of this application, optionally, the distance between the first end 43 and the electrode body 51 is L1, the distance between the first end 43 and the overlapping portion 6 is L2, and the ratio of L1 to L2 ranges from 1:2 to 1:1.

[0109] In the extending direction of the tab 52, a portion of the tab 52 located between the overlapping portion 6 and the electrode body 51 is covered by the seal 4, and the length of the tab 52 covered by the seal 4 is not less than the length not covered by the seal 4.

[0110] For example, the ratio of L1 to L2 can be any ratio among 1:2, 3:5, 7:10, 4:5, and 1:1, or any intermediate value between any two adjacent ratios mentioned above.

[0111] In the technical solution of this application embodiment, the ratio of L1 to L2 is in the range of 1:2 to 1:1, which can increase the proportion of the electrode tab 52 covered by the sealant 4 between the overlapping part 6 and the electrode body 51, thereby improving the connection strength and service life of the electrode tab 52.

[0112] like Figure 7 As shown, according to some embodiments of this application, optionally, the distance between the first end 43 and the electrode body 51 is not less than 0.5 mm, and the distance between the first end 43 and the overlapping portion 6 is not less than 1 mm.

[0113] The distance between the first end 43 and the electrode body 51 can be from 0.5 mm to 1 mm, so as to leave a slit between the first end 43 and the electrode body 51. The distance between the first end 43 and the electrode body 51 can also exceed 1 mm.

[0114] For example, the distance between the first end 43 and the electrode body 51 can be any value among 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm, and 1mm, or any intermediate value between any two adjacent values ​​mentioned above.

[0115] For example, the distance between the first end 43 and the overlapping portion 6 can be 1mm, 1.1mm, 1.2mm, 1.3mm, 1.4mm, 1.5mm, 1.6mm, 1.7mm, 1.8mm, 1.9mm, 2mm, etc., while leaving a slit of not less than 0.5mm between the first end 43 and the electrode body 51.

[0116] In the technical solution of this application embodiment, the distance between the first end 43 and the electrode body 51 is not less than 0.5mm, which allows for allowance for systematic errors such as assembly errors and processing errors, reducing the potential risk of damage to the electrode body 51 due to interference. The distance between the first end 43 and the overlapping portion 6 is not less than 1mm, which allows for allowance for systematic errors such as assembly errors and processing errors, improving the reliability of the seal 4 covering the overlapping portion 6.

[0117] like Figure 7 As shown, according to some embodiments of this application, optionally, the distance between the second end 44 and the overlapping portion 6 is L3, the distance between the second end 44 and the free end of the electrode terminal 2 is L4, and the ratio of L3 to L4 ranges from 1:3 to 3:4.

[0118] The distance between the second end 44 and the free end of the electrode terminal 2 is greater than the distance between the second end 44 and the overlapping portion 6. In the extending direction of the tab 52, the length of the electrode terminal 2 remaining outside the housing 3 is greater than the length between the overlapping portion 6 and the seal of the housing 3.

[0119] For example, the ratio of L3 to L4 can be any ratio among 1:3, 5:12, 1:2, 7:12, 2:3, and 3:4, or any intermediate value between any two adjacent ratios mentioned above.

[0120] In the technical solution of this application embodiment, the ratio of L3 to L4 is in the range of 1:3 to 3:4, which can increase the length of the electrode terminal 2 outside the housing 3, making it easier for the electrode terminal 2 to be connected to the battery device and the power device.

[0121] like Figure 7As shown, according to some embodiments of this application, optionally, the distance between the second end 44 and the solder area 61 is not less than 20 mm.

[0122] The weak points in the connection between tabs 52 and between tabs 52 and electrode terminal 2 are the solder joints. Therefore, sealing and securing the solder joint area 61 is of paramount importance. Using the solder joint area 61 as a reference, key protection of the solder joint can be achieved.

[0123] In the technical solution of this application embodiment, the distance between the second end 44 and the soldering area 61 is not less than 20mm, which can increase the distance between the soldering area 61 and the sealing point of the outer casing 3, and reduce the influence of the external force of the battery cell 1 on the tab 52.

[0124] like Figure 5 and Figure 7 As shown, according to some embodiments of this application, optionally, the distance between the second end 44 and the free end of the electrode terminal 2 ranges from 25mm to 35mm.

[0125] When the seal 4 is connected to the housing 3, the second end 44 corresponds to the sealing point of the housing 3 on the electrode terminal 2. The length between the free end of the electrode terminal 2 and the second end 44 is the length of the electrode terminal 2 exposed outside the housing 3. When in use, this part can be connected to the battery device 100 and the power device.

[0126] For example, the distance between the second end 44 and the free end of the electrode terminal 2 can be any value among 25mm, 26mm, 27mm, 28mm, 29mm, 30mm, 31mm, 32mm, 33mm, 34mm, and 35mm, or any intermediate value between any two adjacent values ​​mentioned above.

[0127] When the distance between the second end 44 and the free end of the electrode terminal 2 is less than 25mm, the length of the electrode terminal 2 connected to the circuit is too small, and the pulling of the external components on the electrode terminal 2 affects the connection strength of the tab 52. When the distance between the second end 44 and the free end of the electrode terminal 2 is greater than 35mm, the length of the electrode terminal 2 exposed outside the housing 3 is too large, which not only wastes materials, but also easily affects the structural strength of the electrode terminal 2 (the electrode terminal 2 is easily bent and damaged).

[0128] In the technical solution of this application embodiment, the distance between the second end 44 and the free end of the electrode terminal 2 is in the range of 25mm to 35mm, which can take into account both the structural strength of the electrode terminal 2 and the connection strength of the tab 52, thereby improving the reliability of the battery cell 1.

[0129] According to some embodiments of this application, this application also provides a battery device 100, including a battery cell 1 of any of the above schemes.

[0130] According to some embodiments of this application, this application also provides an electrical device, including a battery device 100 of any of the above schemes, the battery device 100 being used to provide electrical energy to the electrical device.

[0131] The power supply device can be any of the aforementioned devices or systems that utilize battery device 100.

[0132] like Figure 3 , Figures 5 to 10 As shown, according to some embodiments of this application, this application provides a battery cell 1, which includes a casing 3, an electrode assembly 5, electrode terminals 2, and a sealing member 4. The electrode assembly 5 includes an electrode body 51 and tabs 52. The tabs 52 overlap with the electrode assembly 5 to form an overlap portion 6, which is ultrasonically welded to form a solder area 61. In the extending direction of the tabs 52, the sealing member 4 fits against the outer side of the electrode terminals 2 and the tabs 52, sealing the entire outer surface of the overlap portion 6. The first end 43 of the sealing member 4 extends beyond the overlap portion 6, leaving a gap of at least 0.5 mm with the electrode body 51, and also seals a portion of the tabs 52 located between the overlap portion 6 and the electrode body 51. The second end 44 extends beyond the solder area 61 by at least 20 mm, and also seals a portion of the electrode terminals 2 located between the overlap portion 6 and the free end of the electrode terminals 2. The sealing member 4 is thermally fused to the casing 3, achieving a seal of the casing 3 at the electrode terminals 2.

[0133] When the seal 4 is formed on the electrode terminal 2 and the tab 52, the welded electrode assembly 5 and the electrode terminal 2 are placed into the seal mold, hot-melt injection molding of sealant is performed, and then cold-pressed to form the seal 4, thereby achieving the connection between the seal 4 and the electrode terminal 2 and the tab 52. The seal 4 can completely cover the welded part on the overlapping part 6, effectively restraining the tab 52 and reducing cracking and detachment of the tab 52 at the weld mark; the seal 4 can seal the weld mark on the overlapping part 6, thereby reducing lithium plating at the tab 52; the seal 4 uses hot-melt adhesive, eliminating the need for additional weld mark protection tape, which can reduce the impact on the energy density of the battery cell 1, and the seal 4 can assist the outer casing 3 in achieving hot-melt sealing, with good compatibility with the electrolyte, which can improve the sealing performance of the outer casing 3.

[0134] The following tests were conducted on the battery cells of the related technologies and the battery cells of this application:

[0135] like Figure 3 As shown, taking the fabrication of a battery cell with a length of 235mm and a width of 150mm as an example, the electrode assembly is stacked, and the positive electrode sheet has a size of 138*200mm. 2 The negative electrode size is 141*203mm. 2 The size of the isolation component is 147*210mm. 2The electrode assembly is stacked with 34 layers of positive electrode and 35 layers of negative electrode. After stacking, the electrode assembly is hot-pressed. After hot pressing, the electrode terminals are ultrasonically welded to the tabs of the electrode assembly.

[0136] After welding, the electrode assembly and electrode terminals of the first group of battery cells are placed into the sealing mold. The sealant (hot melt adhesive) is injected into the mold after hot melting and cold pressing to obtain the sealing component. The positive electrode tab and the negative electrode tab are both connected to the sealing component.

[0137] The electrode assembly and electrode terminals of the second group of battery cells are welded and then placed into the sealing mold. The sealant is hot-melted and injected into the mold, and then cold-pressed to form the sealing component. Only the positive electrode tab is connected to the sealing component.

[0138] The electrode assembly and electrode terminals of the third group of battery cells are welded and then placed into the sealing mold. The sealant is hot-melted and injected into the mold, and then cold-pressed to form the sealing component. Only the negative electrode tab is connected to the sealing component.

[0139] After welding, protective tape is applied to the solder areas on the positive and negative electrode tabs of the fourth group of battery cells.

[0140] After the electrode assembly and electrode terminals of the fifth group of battery cells are welded, the solder areas on the positive and negative electrode tabs are coated with adhesive, such as high-temperature silicone, polyacrylic acid, or organosilicon pressure-sensitive adhesive.

[0141] The tests were conducted using lithium metal secondary pouch cells and silicon carbide secondary pouch cells, respectively.

[0142] When the battery cell is a lithium metal rechargeable pouch cell, the formation process is as follows:

[0143] 1. Rest for 10 minutes;

[0144] 2. 0.2C CCCV 4.3V (constant current and constant voltage charging, using 0.2 times the rated capacity as the constant current charging current until the voltage reaches 4.3V);

[0145] 3. Rest for 10 minutes;

[0146] 4. 1C DC 2.8V (constant current discharge, performing constant current discharge at the rated capacity until the voltage drops to 2.8V);

[0147] 5. 0.2CCCV 3.9V (Resumption charging: use 0.2 times the rated capacity as the constant current charging current until the battery voltage reaches 3.9V. Then charge in a constant voltage manner until the charging current decreases to 0.05C, indicating that 3.9V has been reached).

[0148] The loop test process is as follows:

[0149] 1. Rest for 5 minutes;

[0150] 2. 0.2C CCCV 4.3V (constant current and constant voltage charging, using 0.2 times the rated capacity as the constant current charging current until the voltage reaches 4.3V, then switching to constant voltage charging, maintaining the voltage stable until the charging current decreases to 0.05C);

[0151] 3. Rest for 5 minutes;

[0152] 4. 1C DC 2.8V (constant current discharge, performing constant current discharge at the rated capacity until the voltage drops to 2.8V);

[0153] 5. Repeat steps 1 to 4 until the capacity decays to ≤ 80% (Capacity decay test: repeat steps 1 to 4 to form a loop test process. The test ends when the capacity decays to 80% or less of the initial capacity).

[0154] When the battery cell is a silicon-carbon rechargeable pouch cell, the formation process is as follows:

[0155] 1. Rest for 10 minutes;

[0156] 2. 0.05C CC 3V (Pre-charge, using 0.05 times the battery's rated capacity as the constant current charging current to charge the battery voltage to 3V);

[0157] 3. Rest for 10 minutes;

[0158] 4. 0.1C CC 3.4V (Stage charging, using 0.1 times the rated capacity as the constant current charging current to charge the battery voltage to 3.4V);

[0159] 5. Rest for 10 minutes;

[0160] 6. 0.2C CCCV 3.75V (Constant current and constant voltage charging to full charge, using 0.2 times the rated capacity as the constant current charging current to charge the battery voltage to 3.75V, then switching to constant voltage charging until the charging current decreases to 0.05C, indicating that 3.75V has been reached).

[0161] The loop test process is as follows:

[0162] 1. Rest for 5 minutes;

[0163] 2. 1 / 3C CCCV 4.25V (constant current and constant voltage charging, using 1 / 3 of the rated capacity as the constant current charging current until the voltage reaches 4.25V, then switching to constant voltage charging, maintaining the voltage stable until the charging current decreases to 0.05C);

[0164] 3. Rest for 5 minutes;

[0165] 4. 1 / 3C DC 2.5V (constant current discharge, using 1 / 3 of the rated capacity as the constant current discharge current until the voltage drops to 2.5V);

[0166] 5. Repeat steps 1 to 4 until the capacity decays to ≤ 80% (Capacity decay test: repeat steps 1 to 4 to form a loop test process. The test ends when the capacity decays to 80% or less of the initial capacity).

[0167] The following are the conditions after disassembly of each group of battery cells after formation and cycling: Group 1 battery cells had normal solder marks after formation and normal solder marks after cycling; Group 2 battery cells had solder marks detached from the negative electrode tab after formation and cracked, detached, and had lithium plating on the negative electrode tab after cycling; Group 3 battery cells had normal solder marks after formation and cracked solder marks on the positive electrode tab after cycling; Group 4 battery cells had discolored adhesive tape and detached solder marks on the negative electrode tab after formation and cracked solder marks on the negative electrode tab after cycling; Group 5 battery cells had discolored colloid and detached solder marks on the negative electrode and cracked solder marks on the negative electrode tab after formation.

[0168] like Figure 4 As shown, taking the fabrication of a battery cell with a length of 260mm and a width of 110mm as an example, the electrode assembly is stacked, and the positive electrode sheet has a size of 98*200mm. 2 The negative electrode size is 101*203mm. 2 The size of the isolation component is 107*210mm. 2 The electrode assembly is stacked with 34 layers of positive electrode and 35 layers of negative electrode. After stacking, the electrode assembly is hot-pressed. After hot pressing, the electrode terminals are ultrasonically welded to the tabs of the electrode assembly.

[0169] After welding, the electrode assembly and electrode terminals of the sixth group of battery cells are placed into the sealing mold. The sealant is then injected into the mold after hot melting and cold pressing to obtain the sealing component. The positive electrode tab and the negative electrode tab are both connected to the sealing component.

[0170] The electrode assembly and electrode terminals of the seventh group of battery cells are placed into the sealing mold after welding. The sealant is injected into the mold after hot melting and cold pressing to obtain the sealing component. Only the positive electrode tab is connected to the sealing component.

[0171] After welding, the electrode assembly and electrode terminals of the eighth group of battery cells are placed into the sealing mold. The sealant is then injected into the mold after hot melting and cold pressing to obtain the sealing component. Only the negative electrode tab is connected to the sealing component.

[0172] After welding, protective tape is applied to the solder areas on the positive and negative electrode tabs of the ninth group of battery cells.

[0173] After welding, the electrode assembly and electrode terminals of the tenth group of battery cells are coated with adhesive, such as high-temperature silicone, polyacrylic acid, or organosilicon pressure-sensitive adhesive.

[0174] The tests were conducted using lithium metal secondary pouch cells and silicon carbide secondary pouch cells, respectively.

[0175] When the battery cell is a lithium metal rechargeable pouch cell, the formation process is as follows:

[0176] 1. Rest for 10 minutes;

[0177] 2. 0.2C CCCV 4.3V;

[0178] 3. Rest for 10 minutes;

[0179] 4. 1C DC 2.8V;

[0180] 5. 0.2CCCV 3.9V.

[0181] The loop test process is as follows:

[0182] 1. Rest for 5 minutes;

[0183] 2. 0.2C CCV 4.3V;

[0184] 3. Rest for 5 minutes;

[0185] 4. 1C DC 2.8V;

[0186] 5. Repeat steps 1 to 4 until the capacity fading is ≤ 80%.

[0187] When the battery cell is a silicon-carbon rechargeable pouch cell, the formation process is as follows:

[0188] 1. Rest for 10 minutes;

[0189] 2. 0.05C CC 3V;

[0190] 3. Rest for 10 minutes;

[0191] 4. 0.1C CC 3.4V;

[0192] 5. Rest for 10 minutes;

[0193] 6. 0.2C CCCV 3.75V;

[0194] The loop test process is as follows:

[0195] 1. Rest for 5 minutes;

[0196] 2. 1 / 3C CCCV 4.25V;

[0197] 3. Rest for 5 minutes;

[0198] 4. 1 / 3C DC 2.5V;

[0199] 5. Repeat steps 1 to 4 until the capacity fading is ≤ 80%.

[0200] The disassembly results after formation and cycling were as follows: For the sixth group of battery cells, the solder marks were normal after formation and normal after cycling; for the seventh group of battery cells, the solder marks on the negative electrode tabs fell off after formation and fell off after cycling; for the eighth group of battery cells, the solder marks were normal after formation, but the solder marks on the positive electrode tabs partially cracked after cycling; for the ninth group of battery cells, the tape changed color after formation, the solder marks on the negative electrode tabs fell off, and the solder marks on the negative electrode tabs cracked after cycling; for the tenth group of battery cells, the colloid changed color after formation, the solder marks on the negative electrode tabs fell off, and the solder marks on the negative electrode tabs cracked after cycling.

[0201] Through testing and verification, it has been found that the battery cell disclosed in this application can effectively protect the solder joints of the electrode tabs by setting a seal, thereby improving the reliability and service life of the battery cell.

[0202] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and not to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. These modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application, and they should all be covered within the scope of the claims and specification of this application. In particular, as long as there is no structural conflict, the various technical features mentioned in the embodiments can be combined in any way. This application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A battery cell, characterized by, include: The outer casing has a receiving cavity; An electrode assembly is disposed within the receiving cavity. The electrode assembly includes an electrode body and a tab, with the tab extending from the electrode body. The electrode terminal is overlapped with the electrode tab to form an overlap portion, and the overlap portion is provided with a solder area; A seal is provided at least between the overlapping portion and the housing, and covers the solder area; the seal includes a large face portion and a side face portion, two opposite large face portions are connected by two side face portions, the large face portion covers at least the large face portion of the overlapping portion, and the side face portion covers at least the side face portion of the overlapping portion.

2. The battery cell of claim 1, wherein, The thickness of the large face portion ranges from 0.15 mm to 0.25 mm, and the thickness of the side portion ranges from 3 mm to 5 mm.

3. The battery cell of claim 1, wherein, In the extending direction of the tab, the thickness of the side portion gradually decreases at the end facing the electrode body.

4. The battery cell according to any one of claims 1 to 3, characterized in that, In the extending direction of the tab, the distance between the two sides of the solder area is less than the distance between the two sides of the overlapping portion.

5. The battery cell according to any one of claims 1 to 3, characterized in that, In the extending direction of the tab, the seal includes a first end and a second end opposite to each other, the first end being located between the solder area and the electrode body, and the second end being located between the free end of the electrode terminal and the solder area, wherein the distance between the first end and the solder area is less than the distance between the second end and the solder area.

6. The battery cell of claim 5, wherein, The first end is located between the overlapping portion and the electrode body, and the second end is located between the free end of the electrode terminal and the overlapping portion.

7. The battery cell of claim 6, wherein, The distance between the first end and the electrode body is L1, and the distance between the first end and the overlapping portion is L2. The ratio of L1 to L2 is in the range of 1:2 to 1:

1.

8. The battery cell of claim 6, wherein, The distance between the first end and the electrode body is not less than 0.5 mm, and the distance between the first end and the overlapping portion is not less than 1 mm.

9. The battery cell of claim 5, wherein, The distance between the second end and the overlapping portion is L3, and the distance between the second end and the free end of the electrode terminal is L4. The ratio of L3 to L4 ranges from 1:3 to 3:

4.

10. The battery cell according to claim 5, characterized in that, The distance between the second end and the solder area is not less than 20mm.

11. The battery cell of claim 5, wherein, The distance between the second end and the free end of the electrode terminal ranges from 25mm to 35mm.

12. A battery device characterized by comprising: Includes the battery cell as described in any one of claims 1 to 11.

13. An electrical device, comprising: Includes the battery device as described in claim 12, the battery device being used to provide electrical energy.

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