Battery cell, battery device, and electric device

Abstract

Provided in the embodiments of the present application are a battery cell, a battery device, and an electric device. The battery cell comprises a housing, an electrode assembly, an electrolyte, and a positive terminal, wherein the housing comprises a first wall, a second wall, and a side wall; the first wall and the second wall are oppositely arranged on two sides of the side wall and enclose an accommodating cavity with the side wall; the material of the first wall comprises iron, chromium, or nickel; the electrode assembly is arranged in the accommodating cavity; the electrolyte is accommodated in the accommodating cavity and infiltrates at least part of the electrode assembly; the positive terminal is arranged on the first wall, and the positive terminal is electrically connected to the electrode assembly; and the housing is provided with a liquid injection hole extending through the housing. The liquid injection hole is arranged on the first wall, and the minimum distance between the liquid injection hole and the positive terminal is not less than 20 mm; and / or the liquid injection hole is arranged on the second wall or the side wall.

Description

Battery cells, battery packs and electrical devices Technical Field

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

[0002] Energy conservation and emission reduction are key to the sustainable development of the automotive industry, and electric vehicles, due to their energy-saving and environmentally friendly advantages, have become an important component of this sustainable development. For electric vehicles, battery technology is a crucial factor in their development.

[0003] Battery production involves processes such as electrolyte injection. During this process, electrolyte spillage can occur, causing electrolyte to flow between the terminals and the casing. Once the terminals are conductive, potential differences can lead to casing corrosion, affecting battery lifespan. Therefore, reducing the risk of internal corrosion in individual battery cells is a pressing issue that needs to be addressed. Summary of the Invention

[0004] This application provides a battery cell, a battery device, and an electrical device that can reduce the risk of internal corrosion in the battery cell due to potential issues, thereby improving the reliability and service life of the battery cell.

[0005] In a first aspect, this application provides a battery cell, including a casing, an electrode assembly, an electrolyte, and a positive electrode post. The casing includes a first wall, a second wall, and a side wall. The first wall and the second wall are disposed opposite each other on both sides of the side wall and enclose the side wall to form a receiving cavity. The material of the first wall includes iron, chromium, or nickel. The electrode assembly is disposed in the receiving cavity, and the electrolyte is contained in the receiving cavity. The electrolyte wets at least a portion of the electrode assembly. The positive electrode post is disposed on the first wall and is electrically connected to the electrode assembly. The casing is provided with an injection hole that penetrates the casing. The injection hole is disposed on the first wall, and the minimum distance between the injection hole and the positive electrode post is not less than 20 mm. And / or, the injection hole is disposed on the second wall or the side wall.

[0006] In this embodiment, by setting the injection hole away from the positive electrode post, the positive electrode post can be located outside the injection range of the injection hole. This reduces the risk of electrolyte flowing between the positive electrode post and the first wall when electrolyte is sprayed during the injection process. This also prevents chemical corrosion of the casing due to potential issues when the positive electrode post is conducting, thereby improving the reliability and service life of the battery cell.

[0007] In some embodiments, the first wall is made of steel, which has high strength, can meet the strength requirements of the outer shell, and is easy to process and has low cost.

[0008] In this embodiment, since the main components of steel are iron, chromium, and nickel, when the material of the first wall is steel and the liquid injection hole is located on the first wall, by ensuring that the minimum distance between the liquid injection hole and the positive electrode post is not less than 20mm, it is possible to meet the strength requirements of the casing while preventing the problem of chemical corrosion of the casing due to potential issues, thereby improving the reliability and service life of the battery cell.

[0009] In some embodiments, the material of the first wall is stainless steel or carbon steel.

[0010] In some embodiments, at least one of the second wall and the sidewall is made of iron, chromium, or nickel, which allows the material of at least one of the second wall and the sidewall to be the same as that of the first wall, thereby simplifying the structure of the housing and reducing the manufacturing cost of the housing.

[0011] In some embodiments, at least one of the second wall and the side wall is made of steel.

[0012] In some embodiments, the electrolyte includes a fluorinated lithium salt, which can improve the electrochemical stability of the electrolyte system, increase the conductivity of the electrolyte, and improve the performance of the battery cells.

[0013] In some embodiments, the fluorinated lithium salt includes at least one of lithium tetrafluoroborate, lithium hexafluoroarsenate, lithium hexafluorophosphate, lithium difluorooxalate borate, lithium bis(fluorosulfonyl)imide, and lithium bis(trifluoromethylsulfonyl)imide.

[0014] In some embodiments, the battery cell further includes a negative electrode post disposed on a first wall, a positive electrode post and a negative electrode post disposed at intervals along a first direction, and an injection hole disposed on the first wall, disposed between the negative electrode post and the positive electrode post along the first direction, or the injection hole is disposed on the side of the negative electrode post away from the positive electrode post along the first direction.

[0015] In this embodiment, when both the positive and negative electrode posts are disposed on the first wall, the injection hole can be disposed on the first wall and located on the side away from the positive electrode post. This makes it easier to increase the distance between the injection hole and the positive electrode post, given the limited size of the battery cell, thereby further reducing the risk of electrolyte flowing into the space between the positive electrode post and the first wall when the injection hole sprays liquid, and improving the reliability of the battery cell.

[0016] In some embodiments, the minimum distance between the injection hole and the positive electrode post is greater than or equal to the minimum distance between the injection hole and the negative electrode post, which can increase the distance between the injection hole and the positive electrode post and further reduce the risk of electrolyte flowing into the space between the positive electrode post and the first wall when the injection hole is sprayed.

[0017] In some embodiments, the battery cell further includes a negative electrode post disposed on the first wall, and an injection hole disposed on one of the side wall and the second wall.

[0018] In this embodiment, when both the positive and negative terminals are located on the first wall, the injection hole can be located on one of the side wall and the second wall. The electrolyte ejected from the injection hole will not flow to the first wall, thereby significantly reducing the risk of internal corrosion of the casing due to potential issues.

[0019] In some embodiments, the sidewall includes a first sidewall and a second sidewall that are intersected, the area of ​​the first sidewall being smaller than the area of ​​the second sidewall, and an injection hole being disposed on one of the first sidewall and the second sidewall.

[0020] In some embodiments, the battery cell further includes a negative electrode post, and both the negative electrode post and the electrolyte injection hole are disposed on the second wall. That is, when the positive electrode post and the negative electrode post are disposed on different wall portions, the electrolyte injection hole can be disposed on the negative electrode post side. This reduces the risk of internal corrosion of the battery cell, shortens the electrolyte injection path, and allows the electrolyte to enter the battery cell more quickly, thereby improving the electrolyte wetting efficiency and production efficiency, and improving the overall performance of the battery cell.

[0021] In some embodiments, the battery cell further includes a first insulating plastic, which is assembled between the housing and the negative terminal. The injection hole and the negative terminal are located on different walls of the housing, or the injection hole and the negative terminal are located on the same wall of the housing. The minimum distance between the injection hole and the outer edge of the first insulating plastic is greater than or equal to 8 mm, thereby effectively reducing the risk of burning the first insulating plastic when welding the sealing pin to the injection hole, and improving the reliability of the battery cell.

[0022] In some embodiments, the battery cell further includes a pressure relief mechanism. The injection hole and the pressure relief mechanism are located on different walls of the housing, or the injection hole and the pressure relief mechanism are located on the same wall of the housing. The minimum distance between the outer edges of the injection hole and the pressure relief mechanism is greater than or equal to 8 mm, thereby effectively reducing the risk of burning the pressure relief mechanism when welding the sealing nail to the injection hole, and improving the reliability of the battery cell.

[0023] In some embodiments, the battery cell further includes a second insulating plastic, which is assembled between the housing and the positive terminal, and the second insulating plastic has an insulation resistance greater than 200MΩ at a voltage of 500V.

[0024] In some embodiments, the second insulating plastic includes one of polypropylene, polyphenylene sulfide, and tetrafluoroethylene.

[0025] Secondly, embodiments of this application provide a battery device including a plurality of battery cells according to the first aspect.

[0026] Thirdly, embodiments of this application provide an electrical device, including the battery device of the second aspect.

[0027] 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

[0028] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the embodiments of this application will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on the drawings without creative effort.

[0029] Figure 1 is a schematic diagram of the vehicle structure provided in some embodiments of this application;

[0030] Figure 2 is an exploded schematic diagram of a battery device provided in some embodiments of this application;

[0031] Figure 3 is a schematic diagram of the structure of a battery cell provided in some embodiments of this application;

[0032] Figure 4 is an exploded schematic diagram of a battery cell provided in some embodiments of this application;

[0033] Figure 5 is a schematic diagram of the structure of a battery cell provided in some other embodiments of this application;

[0034] Figure 6 is a schematic diagram of the structure of a battery cell provided in some embodiments of this application;

[0035] Figure 7 is a schematic diagram of the structure of a battery cell provided in some embodiments of this application;

[0036] Figure 8 is a top view of a battery cell provided in some embodiments of this application.

[0037] The reference numerals in the detailed embodiments are as follows:

[0038] 100 battery packs, 200 controllers, 300 motors;

[0039] 10 individual battery cells, 20 casing cells;

[0040] 1. Outer shell, 11. First wall, 12. Second wall, 13. Side wall, 131. First side wall, 132. Second side wall, 2. Electrode assembly, 21. Positive electrode tab, 22. Negative electrode tab, 3. Positive electrode post, 4. Liquid injection hole, 5. Negative electrode post, 6. Sealing nail, 7. First insulating plastic, 8. Second insulating plastic, 9. Pressure relief mechanism.

[0041] X is the first direction, Y is the third direction, and Z is the second direction. Detailed Implementation

[0042] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0043] Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used in the description of this application 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 description, claims, and accompanying drawings of this application are intended to cover non-exclusive inclusion. The terms "first," "second," etc., in the description, claims, or accompanying drawings of this application are used to distinguish different objects, not to describe a specific order or hierarchy.

[0044] In this application, the reference to "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 in the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment that is mutually exclusive with other embodiments.

[0045] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "attachment" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0046] 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, or B existing alone. Additionally, in this application, the character " / " generally indicates that the preceding and following related objects have an "or" relationship.

[0047] In the embodiments of this application, the same reference numerals denote the same components, and for the sake of brevity, detailed descriptions of the same components are omitted in different embodiments. It should be understood that the thickness, length, width, and other dimensions of various components in the embodiments of this application shown in the accompanying drawings, as well as the overall thickness, length, width, and other dimensions of the integrated device, are merely illustrative and should not constitute any limitation on this application.

[0048] The "range" disclosed in this application is defined by a lower limit and an upper limit. A given range is defined by selecting a lower limit and an upper limit, which define the boundaries of the particular range. Ranges defined in this way can include or exclude endpoints and can be arbitrarily combined; that is, any lower limit can be combined with any upper limit to form a range. For example, if ranges of 60 to 120 and 80 to 110 are listed for a specific parameter, it is also expected that ranges of 60 to 110 and 80 to 120 are also included. Furthermore, if minimum range values ​​of 1 and 2 are listed, and if maximum range values ​​of 3, 4, and 5 are listed, then the following ranges are all expected: 1 to 3, 1 to 4, 1 to 5, 2 to 3, 2 to 4, and 2 to 5. In this application, unless otherwise stated, the numerical range "a to b" represents a shortened representation of any combination of real numbers between a and b, where a and b are real numbers. For example, the numerical range "0 to 5" means that all real numbers between "0 and 5" have been listed in this article; "0 to 5" is just a shortened representation of these numerical combinations. In addition, when a parameter is stated as an integer ≥ 2, it is equivalent to disclosing that the parameter is, for example, an integer 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0049] In this application, "multiple" means two or more (including two).

[0050] 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.

[0051] The battery cell includes a housing and an electrolyte filling port on the housing. The battery cell also includes an outer casing and an electrode assembly, which is disposed within the outer casing to isolate the internal and external environments. The battery cell further includes terminals mounted on the outer casing, which are electrically connected to the electrode assembly via adapter plates. To improve energy density, the electrode assembly of the battery cell is relatively large and fits tightly against the end cap assembly. Therefore, the end of the battery cell opposite the inner side of the electrolyte filling port is blocked by various components, such as adapter plates and electrode plates. This results in obstructed electrolyte flow and low filling efficiency during electrolyte filling, and also easily leads to electrolyte spraying during filling, causing electrolyte to flow between the terminals and the outer casing.

[0052] In lithium batteries, the positive electrode is at a relatively high potential. Since steel is primarily composed of iron (Fe), chromium (Cr), and nickel (Ni), at high potentials, iron, chromium, and nickel atoms tend to lose electrons and be oxidized. When the insulation between the positive electrode and the casing of a lithium battery is compromised, an electron pathway forms between the positive electrode and the casing, and an ion pathway forms inside the battery. The potential of the casing is increased by the positive electrode, making the oxidation of iron, chromium, and nickel in the casing more likely to occur. Fe, Cr, and Ni in the casing lose electrons, which then participate in the lithium intercalation reaction at the positive electrode through the external circuit. In electrolyte solutions containing fluoride ions and other anionic groups, the resulting ferrous ions can combine with fluoride ions and other anions, causing varying degrees of corrosion to the casing and affecting battery life.

[0053] Based on the above considerations, in order to reduce the risk of corrosion of the battery casing, this application provides a battery cell. By adjusting the position of the injection hole, the positive electrode post is located outside the injection range of the injection hole, so as to reduce the risk of electrolyte flowing into the positive electrode post and the casing during injection. The battery cell, battery device and power-consuming device in this application embodiment will be described in detail below with reference to Figures 1 to 8.

[0054] The technical solutions described in the embodiments of this application are applicable to the battery device 100 and electrical devices using the battery device 100.

[0055] Electrical devices can include vehicles, mobile phones, portable devices, laptops, ships, spacecraft, electric toys, and power tools. Vehicles can be gasoline-powered cars, natural gas-powered cars, or new energy vehicles; new energy vehicles can be pure electric vehicles, hybrid electric vehicles, or range-extended electric vehicles. Spacecraft include airplanes, rockets, space shuttles, and spacecraft. Electric toys include stationary or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys. Power tools include metal cutting power tools, grinding power tools, assembly power tools, and railway power tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete vibrators, and electric planers. This application does not impose any special limitations on the above-mentioned electrical devices.

[0056] It should be understood that the technical solutions described in the embodiments of this application are applicable to all electrical devices including battery device 100 and those using battery device 100, but for the sake of brevity, the following embodiments are all described using electric vehicles as examples.

[0057] Please refer to Figure 1, which is a schematic diagram of the structure of a vehicle provided in some embodiments of this application.

[0058] The vehicle has a battery device 100 installed inside, which can be located at the bottom, front, or rear of the vehicle. The battery device 100 can be used to power the vehicle; for example, it can serve as the vehicle's operating power source. The vehicle 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 vehicle's power needs during starting, navigation, and driving.

[0059] Please refer to Figure 2, which is an exploded view of a battery device 100 provided in some embodiments of this application.

[0060] The battery device 100 mentioned in the embodiments of this application may include one or more battery cell assemblies for providing voltage and capacity. A battery cell assembly may include multiple battery cells 10, which are connected in series, parallel, or mixed connections via a busbar. A battery cell assembly may be a battery module, which is formed by arranging and fixing multiple battery cells 10 into an independent module.

[0061] In some embodiments, the battery device 100 may be a battery pack, which includes a housing 20 and one or more battery cell assemblies. The battery cell assemblies are housed in the housing 20 to encapsulate one or more battery cells 10 and prevent liquids or other foreign matter from affecting the charging or discharging of the battery cells 10.

[0062] In this embodiment of the application, the battery cell 10 can be a secondary battery, which refers to the battery cell 10 that can be used again after being discharged by recharging to activate the active material.

[0063] Please refer to Figures 3 and 4. Figure 3 is a structural schematic diagram of the battery cell 10 provided in some embodiments of this application, and Figure 4 is an exploded schematic diagram of the battery cell 10 provided in some embodiments of this application.

[0064] This application provides a battery cell 10, including a casing 1, an electrode assembly 2, an electrolyte, a positive electrode post 3, and an injection hole 4.

[0065] The outer casing 1 includes a first wall 11, a second wall 12, and a side wall 13. One of the first wall 11 and the second wall 12 is the top wall and the other is the bottom wall. The first wall 11 and the second wall 12 are disposed opposite each other on both sides of the side wall 13 along the second direction Z and enclose the side wall 13 to form a receiving cavity. The second direction Z can be the height direction of the battery cell 10.

[0066] The receiving cavity can be used to house the electrode assembly 2, electrolyte, and other components, and to isolate the receiving cavity of the housing 1 from the external environment. The housing 1 can be of various shapes and sizes, such as cuboid, cylindrical, hexagonal prism, etc. Specifically, the shape of the housing 1 can be determined according to the specific shape and size of the electrode assembly 2.

[0067] Electrode assembly 2 is disposed within the receiving cavity. Electrode assembly 2 includes a positive electrode, a negative electrode, and a separator, with the separator positioned between the negative and positive electrodes. During the charging and discharging process of the battery cell 10, active ions repeatedly insert and extract between the positive and negative electrodes. The separator, positioned between the positive and negative electrodes, prevents short circuits between the positive and negative electrodes while allowing active ions to pass through. The positive electrode includes a positive current collector and a positive active material layer. The positive active material layer is coated on the surface of the positive current collector and serves as the main body of the positive electrode. The current collector without the positive active material layer serves as the positive electrode tab 21.

[0068] The positive electrode post 3 is disposed on the first wall 11. The material of the first wall 11 includes iron, chromium or nickel. The positive electrode post 3 is used to electrically connect with the positive electrode tab 21 of the electrode assembly 2. The positive electrode post 3 can be directly connected to the positive electrode tab 21, or the positive electrode post 3 can be provided with a corresponding connecting member, or it can also be called a current collector. The connecting member is located between the outer shell 1 and the electrode assembly 2, and is used to electrically connect the positive electrode post 3 and the positive electrode tab 21.

[0069] The injection hole 4 is provided through the outer shell 1. The injection hole 4 is used to inject electrolyte into the receiving cavity. The electrolyte is contained in the receiving cavity and is immersed in at least part of the electrode assembly 2. The electrolyte plays the role of conducting ions between the positive and negative electrodes.

[0070] To reduce the risk of corrosion of the first wall 11, the injection hole 4 in this embodiment is provided on the first wall 11, and the minimum distance between the injection hole 4 and the positive electrode post 3 is not less than 20 mm, and / or, the injection hole 4 is provided on the second wall 12 or the side wall 13.

[0071] In this embodiment of the battery cell 10, when the injection hole 4 is located on the first wall 11, by ensuring that the minimum distance between the injection hole 4 and the positive electrode post 3 is not less than 20mm, the positive electrode post 3 can be located outside the spray range of the injection hole 4. This reduces the risk of electrolyte flowing between the positive electrode post 3 and the first wall 11 when electrolyte spraying occurs during the injection process. In turn, it prevents the problem of chemical corrosion of the outer casing 1 due to potential issues when the positive electrode post 3 is conducting, thereby improving the reliability and service life of the battery cell 10.

[0072] It should be noted that, considering that in the current electrolyte injection process, the maximum spray radius of the injection hole 4 can reach an area of ​​20mm from the center of the injection hole 4, the present embodiment ensures that the minimum distance between the injection hole 4 and the positive electrode post 3 is not less than 20mm, so that the positive electrode post 3 is located outside the spray radius of the injection hole 4. However, according to the electrolyte injection process of other batteries, for example, when the spray radius of the injection hole 4 is greater than 20mm, the minimum distance between the injection hole 4 and the positive electrode post 3 can be appropriately increased to reduce the risk of electrolyte flowing into the space between the positive electrode post 3 and the first wall 11 during injection. That is, the minimum distance between the injection hole 4 and the positive electrode post 3 can be adjusted according to the actual manufacturing requirements of the battery cell 10, as long as it can ensure that the positive electrode post 3 is located outside the spray range of the injection hole 4.

[0073] Furthermore, since the liquid injection hole 4 is located on a wall of the casing, its spray range is limited to that wall. Therefore, when the liquid injection hole 4 and the positive electrode post 3 are located on the same wall (i.e., the liquid injection hole 4 is on the first wall 11), the minimum distance between the liquid injection hole 4 and the positive electrode post 3 must be greater than 20 mm. However, when the liquid injection hole 4 and the positive electrode post 3 are located on different walls, such as the liquid injection hole 4 on the side wall 13 or the second wall 12, the location of the liquid injection hole 4 is not limited by the spray range. It can be located at any position on the side wall 13 or the second wall 12 while meeting the liquid injection requirements of the battery cell 10.

[0074] In some alternative embodiments, the first wall 11 is made of steel. Steel has high strength, which can meet the strength requirements of the shell, and it is easy to process and has a low cost.

[0075] Since the main components of steel are iron, chromium, and nickel, when the material of the first wall 11 is steel and the liquid injection hole 4 is located on the first wall 11, by ensuring that the minimum distance between the liquid injection hole 4 and the positive electrode post 3 is not less than 20mm, it is possible to meet the strength requirements of the outer casing while preventing the problem of chemical corrosion of the outer casing 1 due to potential issues, thereby improving the reliability and service life of the battery cell 10.

[0076] Furthermore, the material of the first wall 11 is stainless steel or carbon steel. If the first wall 11 is made of stainless steel, its structural strength is relatively high, which can usually meet the tensile strength requirements under the aforementioned high-temperature conditions. Moreover, stainless steel is not prone to rust, which can improve the service life of the first wall 11 compared to other materials. If the first wall 11 is made of carbon steel, its structural strength is high, making it easier to meet the tensile strength requirements under the aforementioned high-temperature conditions.

[0077] Similar to the first wall 11, in some alternative embodiments, at least one of the second wall 12 and the side wall 13 is made of iron, chromium or nickel.

[0078] By making at least one of the second wall 12 and the side wall 13 the same as the material of the first wall 11, the structure of the outer casing 1 can be simplified and the manufacturing cost of the outer casing 1 can be reduced.

[0079] In some alternative embodiments, at least one of the second wall 12 and the side wall 13 is made of steel, that is, the outer shell can be set as a steel shell. Steel has high strength, which can meet the strength requirements of the outer shell, and it is easy to process and has low cost.

[0080] Optionally, at least one of the second wall 12 and the side wall 13 may be made of stainless steel or carbon steel, and the specific material may be stainless steel or carbon steel, depending on the requirements of the first wall 11 and the battery cell.

[0081] In some alternative embodiments, the electrolyte includes a fluorinated lithium salt. By including a fluorinated lithium salt in the electrolyte, the electrochemical stability of the electrolyte system can be improved, the conductivity of the electrolyte can be increased, and the performance of the battery cell can be improved.

[0082] Since fluorine-containing lithium salts contain fluoride ions, by setting the injection hole 4 away from the positive electrode post 3, the inflow of electrolyte between the positive electrode post 3 and the first wall 11 can be reduced. This reduces the risk of electrochemical corrosion of the casing 1 due to potential issues in the scenario where the insulation between the positive electrode post 3 and the first wall 11 of the lithium battery is damaged, thereby improving the reliability and service life of the battery cell 10.

[0083] Optionally, the fluorinated lithium salt includes at least one of lithium tetrafluoroborate, lithium hexafluoroarsenate, lithium hexafluorophosphate, lithium difluorooxalate borate, lithium bis(fluorosulfonyl)imide, and lithium bis(trifluoromethanesulfonyl)imide. These types of lithium salts have good solubility and can form a locally high-concentration electrolyte in the negative electrode active layer, thereby improving the stability and ion conductivity of the SEI film.

[0084] It is understandable that, for the injection hole 4, since the effect of its electrolyte spray on the negative electrode post 5 is smaller than its effect on the positive electrode post 3, the opening position of the injection hole 4 on the outer shell 1 can be designed according to the setting position of the positive electrode post 3 and the negative electrode post 5.

[0085] Referring to Figures 3 and 4, in some alternative embodiments, the battery cell 10 further includes a negative terminal post 5 disposed on one of the first wall 11 and the second wall 12.

[0086] The negative electrode includes a negative current collector and a negative active material layer. The negative active material layer is coated on the surface of the negative current collector and serves as the main body of the negative electrode. The current collector without the negative active material layer serves as the negative electrode tab 22. The negative electrode post 5 is disposed on the outer shell 1. The negative electrode post 5 is used for electrical connection with the negative electrode of the electrode assembly 2. The negative electrode post 5 can be directly connected to the electrode assembly 2, or a connecting member can be provided for the negative electrode post 5, or it can also be called a current collector. The connecting member is located between the outer shell 1 and the electrode assembly 2 and is used to electrically connect the negative electrode post 5 and the negative electrode tab 22.

[0087] The negative terminal 5 is located on one of the first wall 11 and the second wall 12. That is, the positive terminal 3 and the negative terminal 5 can be located on the same wall or on different walls. The specific arrangement can be adjusted according to the battery model and the usage environment.

[0088] Referring to Figures 3 and 4, in some optional embodiments, the negative electrode post 5 is disposed on the first wall 11, and the positive electrode post 3 and the negative electrode post 5 are spaced apart along the first direction X. The injection hole 4 is disposed on the first wall 11, and the injection hole 4 is disposed between the negative electrode post 5 and the positive electrode post 3 along the first direction X; alternatively, the injection hole 4 is disposed along the first direction X on the side of the negative electrode post 5 away from the positive electrode post 3.

[0089] When the injection hole 4 is located on the first wall 11, compared to setting the injection hole 4 on the side of the positive electrode post 3 away from the negative electrode post 5, the battery cell 10 in this embodiment, by setting the injection hole 4 along the first direction X between the negative electrode post 5 and the positive electrode post 3, or by setting the injection hole 4 along the first direction X on the side of the negative electrode post 5 away from the positive electrode post 3, can more easily increase the distance between the injection hole 4 and the positive electrode post 3 within the limited size of the battery cell 10, thereby further reducing the risk of electrolyte flowing into the space between the positive electrode post 3 and the first wall 11 when the injection hole 4 is sprayed, and improving the reliability of the battery cell 10.

[0090] Optionally, the first direction X is the length direction of the battery cell 10, so as to make more reasonable use of space and realize the arrangement of the positive electrode post 3, the negative electrode post 5 and the liquid injection hole 4.

[0091] In some alternative embodiments, the minimum distance between the injection port 4 and the positive terminal 3 is greater than or equal to the minimum distance between the injection port 4 and the negative terminal 5.

[0092] When the injection hole 4 is positioned between the negative electrode post 5 and the positive electrode post 3 along the first direction X, the minimum distance between the injection hole 4 and the positive electrode post 3 can be greater than or equal to the minimum distance between the injection hole 4 and the negative electrode post 5. That is, the injection hole 4 is positioned away from the positive electrode post 3, which further reduces the risk of electrolyte flowing into the space between the positive electrode post 3 and the first wall 11 when the injection hole 4 is sprayed, and improves the reliability of the battery cell 10.

[0093] Please refer to Figures 5 to 7. Figure 5 shows a schematic diagram of the structure of a battery cell 10 provided in some other embodiments of this application. Figure 6 shows a schematic diagram of the structure of a battery cell 10 provided in yet another embodiment of this application. Figure 7 shows a schematic diagram of the structure of a battery cell 10 provided in yet another embodiment of this application.

[0094] As another alternative implementation, the negative electrode post 5 is disposed on the first wall 11, and the injection hole 4 is disposed on one of the side wall 13 and the second wall 12.

[0095] When both the positive electrode post 3 and the negative electrode post 5 are located on the first wall 11, the electrolyte injection hole 4 can also be located on one of the side wall 13 and the second wall 12. This allows for a reasonable arrangement of the position of the electrolyte injection hole 4 under the condition that the size of the battery cell 10 is limited, reducing the risk of the electrolyte ejected from the electrolyte injection hole 4 flowing between the positive electrode post 3 and the first wall 11, and improving the reliability of the battery production process.

[0096] When the injection hole 4 is disposed on the side wall 13, in some optional embodiments, the side wall 13 includes a first side wall 131 and a second side wall 132 that are intersected and disposed therebetween. The area of ​​the first side wall 131 is smaller than the area of ​​the second side wall 132, and the injection hole 4 is disposed on one of the first side wall 131 and the second side wall 132.

[0097] Taking a rectangular battery cell 10 as an example, the first sidewall 131 is arranged opposite to each other along the first direction X, and the second sidewall 132 is arranged opposite to each other along the third direction Y, where the third direction Y is the width direction of the battery cell 10. When the liquid injection hole 4 is provided on the sidewall 13, the liquid injection hole 4 can be provided on the first sidewall 131 or the second sidewall 132, and its specific position can be adjusted according to the actual structure of the battery cell 10.

[0098] Optionally, when the injection hole 4 is located on the side wall 13, the vertical distance between the injection hole 4 and the first wall 11 along the second direction Z is less than the vertical distance between the injection hole 4 and the second wall 12 along the second direction Z. By placing the injection hole 4 close to the positive electrode post 3 and the negative electrode post 5, the distance between the injection hole 4 and the positive electrode post 3 and the negative electrode post 5 can be shortened, thereby shortening the electrolyte injection path and allowing the electrolyte to enter the battery cell 10 more quickly. Furthermore, this design also makes the overall structure of the battery cell 10 more compact and rational, helping to reduce the ineffective space inside the battery cell 10 and improve the energy density and overall performance of the battery cell 10.

[0099] As another alternative implementation, both the negative electrode post 5 and the injection hole 4 are disposed on the second wall 12.

[0100] When the positive electrode post 3 is disposed on the first wall 11 and the negative electrode post 5 is disposed on the second wall 12, the electrolyte injection hole 4 can also be disposed on the second wall 12 (not shown in the figure). By disposing the electrolyte injection hole 4 on the second wall 12, since the electrolyte injection hole 4 and the positive electrode post 3 are disposed on the second wall 12 and the first wall 11 respectively, the risk of electrolyte flowing into the positive electrode post 3 when the electrolyte injection hole 4 is sprayed can be largely eliminated. Furthermore, by disposing both the electrolyte injection hole 4 and the negative electrode post 5 on the second wall 12, the electrolyte injection hole 4 can be positioned close to the negative electrode post 5, shortening the electrolyte injection path and allowing the electrolyte to enter the battery cell 10 more quickly, improving the electrolyte wetting efficiency and production efficiency, and enhancing the overall performance of the battery cell 10.

[0101] It is understandable that the injection port 4 may be located on the same wall as the negative electrode post 5, or it may be located on a different wall. When the injection port 4 and the negative electrode post 5 are located on the same wall, although the distance between the center of the injection port 4 and the center of the negative electrode post 5 is not limited by the spray range of the injection port 4, the distance between the center of the injection port 4 and the center of the negative electrode post 5 still cannot be too small.

[0102] Please refer to Figures 3, 4 and 8. Figure 8 shows a top view of a battery cell 10 provided in some embodiments of this application.

[0103] In some alternative embodiments, the battery cell 10 further includes a first insulating plastic 7, which is assembled between the housing 1 and the negative electrode post 5. The liquid injection hole 4 and the negative electrode post 5 are disposed on the same wall. The minimum distance D1 between the liquid injection hole 4 and the outer edge of the first insulating plastic 7 is greater than or equal to 8 mm.

[0104] The first insulating plastic 7 refers to the plastic structure disposed between the negative electrode post 5 and the outer casing 1. Its function is to reduce the risk of electrolyte leakage inside the battery cell 10, and to fix the negative electrode post 5 in a suitable position, effectively isolating the current inside the battery from the external environment, and improving the reliability of the battery cell 10.

[0105] Optionally, the area of ​​the first insulating plastic 7 is larger than the area of ​​the negative electrode post 5 so as to completely cover and protect the electrode post. The first insulating plastic 7 has various shapes, and the outer edge of the first insulating plastic 7 can be circular, square, elliptical or other irregular structures.

[0106] The liquid injection hole 4 and the negative electrode post 5 being located on the same wall means that both the liquid injection hole 4 and the negative electrode post 5 are located on the first wall 11, or both are located on the second wall 12. By ensuring that the minimum distance D1 between the outer edges of the first insulating plastic 7 of the liquid injection hole 4 and the negative electrode post 5 is greater than or equal to 8 mm, the risk of burning the first insulating plastic 7 during subsequent welding of the sealing nail 6 to the liquid injection hole 4 can be effectively reduced, thereby improving the reliability of the battery cell 10.

[0107] In some alternative embodiments, the battery cell 10 further includes a pressure relief mechanism 9, with the injection hole 4 and the pressure relief mechanism 9 disposed on different walls, or the injection hole 4 and the pressure relief mechanism 9 disposed on the same wall, and the minimum distance D2 between the outer edges of the injection hole 4 and the pressure relief mechanism 9 is greater than or equal to 8 mm.

[0108] The pressure relief mechanism 9 is actuated to release internal pressure or temperature when the internal pressure or temperature of the battery cell 10 reaches a predetermined threshold. As an example, when the internal pressure or temperature of the battery cell 10 reaches the predetermined threshold, the pressure relief mechanism 9 actuates or a weak structure within the pressure relief mechanism 9 is broken, thereby creating an opening or channel for the release of internal pressure or temperature. This threshold design varies depending on design requirements. The threshold may depend on the materials of one or more of the positive electrode, negative electrode, electrolyte, and separator in the battery cell 10.

[0109] The term "actuation" as used in this application refers to the pressure relief mechanism 9 being activated or undergoing a certain state, thereby releasing the internal pressure and temperature of the battery cell 10. The actions of the pressure relief mechanism 9 may include, but are not limited to: movement of components within the pressure relief mechanism 9 to form an exhaust channel, rupture, breakage, tearing, or opening of at least a portion of the pressure relief mechanism 9, etc. When the pressure relief mechanism 9 is actuated, the high-temperature, high-pressure substances inside the battery cell 10 are discharged outwards from the actuated portion as exhaust materials. This method enables the battery cell 10 to release pressure and temperature under controllable pressure or temperature conditions, thereby preventing potentially more serious accidents.

[0110] As an example, the pressure relief mechanism 9 can be integrally formed with the housing, or the pressure relief mechanism 9 can be separately set and connected to the housing.

[0111] When the injection hole 4 and the pressure relief mechanism 9 are located on the same wall, the minimum distance D2 between the outer edges of the injection hole 4 and the pressure relief mechanism 9 is greater than or equal to 8mm. This can effectively reduce the risk of burning the pressure relief mechanism 9 when welding the sealing nail 6 to the injection hole 4, and improve the reliability of the battery cell 10.

[0112] In some alternative embodiments, the battery cell 10 further includes a second insulating plastic 8, which is assembled between the housing 1 and the positive terminal 3, and the second insulating plastic 8 has an insulation resistance greater than 200MΩ at a voltage of 500V.

[0113] By making the insulation resistance of the second insulating plastic 8 greater than 200MΩ at 500V, that is, the second insulating plastic 8 can insulate under high voltage, the risk of electrolyte flowing into the positive electrode post 3 and the first wall 11 is further reduced, thereby improving the reliability and service life of the battery cell 10.

[0114] In some alternative embodiments, the second insulating plastic 8 includes one of polypropylene (PP), polyphenylene sulfide (PPS), and tetrafluoroethylene (PFA) to improve the high-voltage insulation performance of the second insulating plastic 8 and improve the thermal conductivity of the second insulating plastic 8, thereby releasing the heat of the battery cell 10 in a timely manner.

[0115] Please refer to Figures 1 to 8. Taking the battery cell 10 in one embodiment of this application as an example, the specific structure of the battery cell 10 in this embodiment of the application will be described.

[0116] The battery cell 10 in this embodiment includes a housing 1, an electrode assembly 2, a positive terminal 3, a negative terminal 5, and a pressure relief mechanism 9. The housing 1 includes a first wall 11, a second wall 12, and a side wall 13. The first wall 11 and the second wall 12 are arranged opposite each other along the second direction Z and enclose the side wall 13 to form a receiving cavity. The housing 1 is made of steel. The electrode assembly 2 is disposed in the receiving cavity. The positive terminal 3 and the negative terminal 5 are spaced apart on the first wall 11 along the first direction X. The positive terminal 3 and the negative terminal 5 are insulated on the housing 1 by the second insulating plastic 8 and the first insulating plastic 7, respectively, and are electrically connected to the electrode assembly 2.

[0117] The outer casing 1 is provided with an injection hole 4, which penetrates the outer casing 1. The injection hole 4 is located on the first wall 11 and is positioned between the positive electrode post 3 and the negative electrode post 5 along the first direction X. The minimum distance between the injection hole 4 and the positive electrode post 3 is not less than 20 mm, and the minimum distance between the injection hole 4 and the first insulating plastic 7 on the negative electrode post 5 is not less than 8 mm. This can prevent electrolyte from flowing into the space between the positive electrode post 3 and the first wall 11 when liquid is sprayed from the injection hole 4, while reducing the risk of burning the first insulating plastic 7 when welding the sealing nail 6 to the injection hole 4, thereby improving the reliability and service life of the battery cell 10.

[0118] The battery device and power-consuming device in the embodiments of this application, since they include the battery cells in the above embodiments, also have the beneficial effects of the battery cell 10 in the above embodiments, which will not be elaborated here.

[0119] 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, all implementation methods and optional implementation methods of this application can be combined to form new technical solutions, and all technical features and optional technical features of this application can be combined to form new technical solutions. 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 single battery cell, comprising: The outer shell includes a first wall, a second wall, and a side wall. The first wall and the second wall are disposed opposite to each other on both sides of the side wall and enclose the side wall to form a receiving cavity. The material of the first wall includes iron, chromium, or nickel. The electrode assembly is disposed within the receiving cavity; An electrolyte is contained in the receiving cavity, and the electrolyte wets at least a portion of the electrode assembly; A positive electrode post is disposed on the first wall, and the positive electrode post is electrically connected to the electrode assembly; The outer casing is provided with a liquid injection hole, which penetrates the outer casing; The injection hole is located on the first wall, and the minimum distance between the injection hole and the positive electrode post is not less than 20 mm; and / or, the injection hole is located on the second wall or the side wall.

2. The battery cell according to claim 1, wherein, The material of the first wall is steel.

3. The battery cell according to claim 2, wherein, The material of the first wall is stainless steel or carbon steel.

4. The battery cell according to any one of claims 1 to 3, wherein, The material of at least one of the second wall and the sidewall includes iron, chromium, or nickel.

5. The battery cell according to claim 4, wherein, The material of at least one of the second wall and the side wall is steel.

6. The battery cell according to any one of claims 1 to 5, wherein, The electrolyte includes fluorinated lithium salts.

7. The battery cell according to claim 6, wherein, The fluorinated lithium salt includes at least one of lithium tetrafluoroborate, lithium hexafluoroarsenate, lithium hexafluorophosphate, lithium difluorooxalate borate, lithium bis(fluorosulfonyl)imide, and lithium bis(trifluoromethylsulfonyl)imide.

8. The battery cell according to any one of claims 1 to 7, wherein, The battery cell further includes a negative electrode post, which is disposed on the first wall, and the positive electrode post and the negative electrode post are spaced apart along a first direction; The injection hole is disposed on the first wall, and the injection hole is disposed between the negative electrode post and the positive electrode post along the first direction, or the injection hole is disposed on the side of the negative electrode post away from the positive electrode post along the first direction.

9. The battery cell according to claim 8, wherein, The minimum distance between the injection port and the positive terminal is greater than or equal to the minimum distance between the injection port and the negative terminal.

10. The battery cell according to any one of claims 1 to 7, wherein, The battery cell also includes a negative electrode post, which is disposed on the first wall, and the liquid injection hole is disposed on one of the side wall and the second wall.

11. The battery cell according to claim 10, wherein, The sidewall includes a first sidewall and a second sidewall that intersect each other, the area of ​​the first sidewall is smaller than the area of ​​the second sidewall, and the injection hole is disposed on one of the first sidewall and the second sidewall.

12. The battery cell according to any one of claims 1 to 7, wherein, The battery cell also includes a negative electrode post, and both the negative electrode post and the liquid injection hole are disposed on the second wall.

13. The battery cell according to any one of claims 8 to 12, wherein, The battery cell also includes a first insulating plastic, which is assembled between the outer casing and the negative electrode post; The injection hole and the negative electrode are located on different parts of the outer casing, or the injection hole and the negative electrode are located on the same part of the outer casing, and the minimum distance between the injection hole and the outer edge of the first insulating plastic is not less than 8 mm.

14. The battery cell according to any one of claims 1 to 13, wherein, The battery cell also includes a pressure relief mechanism; The injection hole and the pressure relief mechanism are located on different parts of the outer shell, or the injection hole and the pressure relief mechanism are located on the same part of the outer shell, and the minimum distance between the injection hole and the outer edge of the pressure relief mechanism is not less than 8 mm.

15. The battery cell according to any one of claims 1 to 14, wherein, The battery cell also includes a second insulating plastic, which is assembled between the outer casing and the positive terminal, and the insulation resistance of the second insulating plastic at 500V is greater than 200MΩ.

16. The battery cell according to claim 15, wherein, The second insulating plastic includes one of polypropylene, polyphenylene sulfide, and tetrafluoroethylene.

17. A battery device comprising a plurality of battery cells according to any one of claims 1 to 16.

18. An electrical device comprising the battery device as claimed in claim 17.

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