Battery cell, battery device and electric device

Abstract

The utility model discloses a battery monomer, a battery device and a power utilization device. Each battery monomer comprises a shell, an electrode assembly and a hydrogen absorption layer, the electrode assembly is arranged in the shell and comprises a positive plate and a negative plate, the positive plate comprises a positive current collector and a positive active material layer arranged on the positive current collector, the negative plate comprises a negative current collector, and the negative current collector protrudes out of the positive active material layer in the first direction; the first direction is perpendicular to the thickness direction of the negative electrode current collector; the hydrogen absorption layer is arranged on the part, protruding out of the positive active material layer in the first direction, of the negative current collector. The energy density of the battery monomer can be 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] In recent years, with the rapid development of new energy technologies, new energy vehicles have been increasingly widely used and are gradually replacing traditional fuel vehicles, becoming one of the mainstream modes of transportation. As the power source of new energy vehicles, the power battery is one of their core components; therefore, the safety performance of the power battery has become a key focus of attention.

[0003] In the development of battery technology, improving the energy density of individual battery cells is a key research direction. Utility Model Content

[0004] This application provides a battery cell, a battery device, and an electrical device that can improve the energy density of the battery cell.

[0005] In a first aspect, embodiments of this application provide a battery cell, which includes a casing, an electrode assembly, and a hydrogen absorption layer. The electrode assembly is disposed inside the casing and includes a positive electrode and a negative electrode. The positive electrode includes a positive current collector and a positive active material layer disposed on the positive current collector. The negative electrode includes a negative current collector that protrudes from the positive active material layer along a first direction, which is perpendicular to the thickness direction of the negative current collector. The hydrogen absorption layer is disposed on the portion of the negative current collector that protrudes from the positive active material layer along the first direction.

[0006] In the above scheme, by protruding the negative electrode current collector out of the positive electrode active material layer in the first direction, the risk of short circuit is reduced. The hydrogen absorption layer can absorb the gas generated during the operation of the battery cell. By placing the hydrogen absorption layer on the extended negative electrode current collector, the utilization of the internal space of the battery cell can be improved, thereby increasing the energy density of the battery cell.

[0007] In some embodiments, the negative electrode current collector has hydrogen absorption layers on both opposite sides along the thickness direction.

[0008] In the above scheme, hydrogen absorption efficiency can be improved by setting hydrogen absorption layers on both sides of the negative electrode current collector.

[0009] In some embodiments, the negative electrode sheet further includes a negative electrode active material layer disposed on the negative electrode current collector, wherein the thickness of the hydrogen absorption layer is less than or equal to the thickness of the negative electrode active material layer along the thickness direction.

[0010] In the above scheme, by setting the thickness of the hydrogen absorption layer to not exceed the thickness of the negative electrode active material layer, the energy density of the battery cell can be maintained.

[0011] In some embodiments, the battery cell is a lithium metal battery cell or a sodium metal battery cell, which has a high theoretical energy density.

[0012] In some embodiments, the negative electrode sheet further includes a conductive film layer disposed in the negative electrode current collector.

[0013] In the above scheme, the conductivity of the battery cell can be improved by setting a conductive film layer on the negative electrode current collector.

[0014] In some embodiments, the battery cell is a sodium-ion battery cell or a sodium metal battery cell, which has higher energy density and better conductivity.

[0015] In some embodiments, the housing includes a top wall and a bottom wall, the bottom wall supporting the electrode assembly, and the hydrogen absorption layer located on the side of the negative electrode current collector near the top wall.

[0016] In the above scheme, by placing the hydrogen absorption layer on the side of the negative electrode current collector close to the top wall of the outer shell, the contact between the hydrogen absorption layer and the electrolyte can be avoided to a certain extent, thereby giving full play to the role of the hydrogen absorption layer.

[0017] In some embodiments, the housing further includes a sidewall, the top wall and the bottom wall are connected through the sidewall, and the battery cell further includes an electrode terminal disposed on the sidewall, the electrode terminal being electrically connected to an electrode assembly.

[0018] In the above scheme, by placing the electrode terminals on the side wall, the safety of the battery cell and the space utilization rate can be increased.

[0019] In some embodiments, the negative current collector includes a first current collector, a second current collector, and a negative electrode tab. The second current collector is provided on opposite sides of the first current collector along a first direction, and a hydrogen absorption layer is provided on at least one of the second current collectors. The negative electrode tab is provided on one side of one of the second current collectors away from the first current collector.

[0020] In the above scheme, by placing the hydrogen absorption layer on one side of the negative electrode tab or on the opposite side of the negative electrode tab, the continuous coating of the hydrogen absorption layer can be achieved, which facilitates the process preparation.

[0021] In some embodiments, a hydrogen absorption layer is provided only in the second current collector section near the negative electrode tab.

[0022] In the above scheme, by limiting the hydrogen absorption layer to a position close to the negative electrode tab, the negative electrode tab can be set upwards, and the hydrogen absorption layer will not be wetted by the electrode liquid, thereby ensuring the effectiveness of the hydrogen absorption layer to a certain extent.

[0023] In some embodiments, along the first direction, the width of the hydrogen absorption layer is L1, and the width of the negative electrode current collector is L2, where L1 and L2 satisfy: 0.007≤L1 / L2≤0.145.

[0024] In the above scheme, by limiting the width ratio of the hydrogen absorption layer to the negative electrode current collector within a suitable range, the hydrogen absorption effect can be guaranteed to a certain extent without occupying too much space in the battery cell, thereby improving the battery energy density.

[0025] In some embodiments, L1 and L2 satisfy: 0.03≤L1 / L2≤0.1.

[0026] In the above scheme, by further limiting the width ratio of the hydrogen absorption layer to the negative electrode current collector, a balance between hydrogen absorption effect and energy density can be further achieved.

[0027] In some embodiments, the areal density of the hydrogen-absorbing layer is d, where d satisfies: 0.3 mg / cm³ 2 ≤d≤13mg / cm 2 .

[0028] In the above scheme, by controlling the range of the areal density of the hydrogen absorption layer, it is easier to control the thickness of the hydrogen absorption layer, so that the coating of the hydrogen absorption layer is uniform and will not affect the energy density of the battery.

[0029] In some embodiments, d satisfies: 1.3 mg / cm³ 2 ≤d≤6.5mg / cm 2 .

[0030] In the above scheme, by further limiting the range of areal density, the coating of the hydrogen absorption layer can be made more uniform, as well as the energy density of the battery cell.

[0031] In some embodiments, the material of the hydrogen absorption layer includes any one of a magnesium alloy, a titanium alloy, or a lanthanum alloy.

[0032] In the above scheme, by selecting the aforementioned materials as the hydrogen absorption layer, the hydrogen absorption effect can be improved.

[0033] Secondly, embodiments of this application also provide a battery device, including a battery cell of any of the above embodiments.

[0034] Thirdly, embodiments of this application also provide an electrical device, including the aforementioned battery device, which is used to provide electrical energy.

[0035] 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

[0036] 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 these drawings without creative effort.

[0037] Figure 1 This is a schematic diagram of the vehicle structure according to some embodiments of this application;

[0038] Figure 2 Exploded views of battery devices according to some embodiments of this application;

[0039] Figure 3 This is a schematic diagram of the structure of a battery module according to some embodiments of this application;

[0040] Figure 4 This is an exploded structural diagram of a battery cell according to some embodiments of this application;

[0041] Figure 5 This is a partial cross-sectional schematic diagram of an electrode assembly according to some embodiments of this application;

[0042] Figure 6 This is a partial cross-sectional schematic diagram of an electrode assembly according to other embodiments of this application;

[0043] Figure 7 This is a partial cross-sectional schematic diagram of an electrode assembly according to some embodiments of this application;

[0044] Figure 8 This is a partial cross-sectional schematic diagram of an electrode assembly in some embodiments of this application;

[0045] Figure 9 This is a cross-sectional schematic diagram of a battery cell according to some embodiments of this application;

[0046] Figure 10 This is a partial cross-sectional schematic diagram of an electrode assembly in some embodiments of this application;

[0047] Figure 11 This is a partial cross-sectional schematic diagram of an electrode assembly in some embodiments of this application.

[0048] Explanation of reference numerals in the attached figures:

[0049] 1000, Vehicle; 100, Battery unit; 200, Controller; 300, Motor; 10, Top cover; 30, Housing; 400, Battery module; 20, Battery cell; 22, Housing; 21, End cap; 23, Electrode assembly; 24, Outer shell; 241, Top wall; 242, Bottom wall; 243, Side wall; 26, Electrode terminal; 40, Hydrogen absorption layer; 50, Positive electrode sheet; 51, Positive current collector; 52, Positive active material layer; 60, Negative electrode sheet; 61, Negative current collector; 611, First current collector; 612, Second current collector; 613, Negative electrode tab; 62, Negative active material layer; 63, Conductive film layer; X, First direction; Y, Thickness direction; 70, Separator. Detailed Implementation

[0050] The embodiments of this application will be described in further detail below with reference to the accompanying drawings and examples. The detailed description of the following embodiments and the accompanying drawings are used to illustrate the principles of this application by way of example, but should not be used to limit the scope of this application, that is, this application is not limited to the described embodiments.

[0051] In the description of this application, it should be noted that, unless otherwise stated, "a plurality of" means two or more; the terms "upper," "lower," "left," "right," "inner," and "outer," etc., indicating orientation or positional relationships, are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on this application. Furthermore, the terms "first," "second," and "third," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance. "Vertical" is not vertical in the strict sense, but within the allowable tolerance range. "Parallel" is not parallel in the strict sense, but within the allowable tolerance range.

[0052] In this application, the reference to "embodiment" means that a specific 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 mutually exclusive, independent, or alternative embodiment. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described in this application can be combined with other embodiments.

[0053] The directional terms used in the following description refer to the directions shown in the figures and are not intended to limit the specific structure of this application. It should also be noted in the description of this application that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" 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. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0054] In this application, the battery cell may include a lithium-ion secondary battery cell, a lithium-ion primary battery cell, a lithium-sulfur battery cell, a sodium-lithium-ion battery cell, a sodium-ion battery cell, or a magnesium-ion battery cell, etc., and the embodiments of this application are not limited thereto. The battery cell may be cylindrical, flat, cuboid, or other shapes, etc., and the embodiments of this application are not limited thereto. Battery cells are generally classified into three types according to their packaging method: cylindrical battery cells, cuboid / square battery cells, and pouch battery cells, and the embodiments of this application are not limited thereto.

[0055] The battery device 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, which are connected in series, parallel, or mixed connections via a busbar.

[0056] In some embodiments, a battery cell assembly is typically formed by arranging multiple battery cells; as an example, a battery cell assembly can be a battery module, which is formed by arranging and fixing multiple battery cells into a single module. As an example, a battery module can be formed by bundling multiple battery cells together with cable ties.

[0057] In some embodiments, the battery device may be a battery pack, which includes a housing and one or more individual battery cell assemblies housed within the housing.

[0058] As an example, the battery cell assembly can be a battery module, which can be housed in a housing by fixing the battery module in the housing.

[0059] As an example, battery cell assemblies can also be housed in a housing by directly fixing multiple battery cells to the housing.

[0060] 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.

[0061] For ease of explanation, the following embodiments will be described using a vehicle 1000 as an example of an electrical device according to an embodiment of this application.

[0062] Please refer to Figure 1 , Figure 1 This is a schematic diagram of the structure of a vehicle provided in some embodiments of this application. The 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 the vehicle 1000, and the battery device 100 can be located at the bottom, front, or rear of the vehicle 1000. The battery device 100 can be used to power the vehicle 1000; for example, the battery device 100 can serve as the operating power source for the vehicle 1000. The vehicle 1000 may also include a controller 200 and a motor 300. The controller 200 is used to control the battery device 100 to supply power to the motor 300, for example, to meet the power needs of the vehicle 1000 during starting, navigation, and driving.

[0063] 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.

[0064] Please refer to Figure 2 , Figure 2 This is an exploded view of the apparatus provided in some embodiments of this application. The battery device 100 includes a battery housing and battery cells 20. In some embodiments, the battery housing may include a top cover 10 and a housing 30, with the top cover 10 and housing 30 covering each other, and the top cover 10 and housing 30 together defining a receiving cavity for receiving the battery cells 20. The housing 30 may be a hollow structure with one end open, and the top cover 10 may be a plate-like structure, with the top cover 10 covering the open side of the housing 30 so that the top cover 10 and housing 30 together define the receiving cavity; the top cover 10 and housing 30 may also be hollow structures with one side open, with the open side of the top cover 10 covering the open side of the housing 30. Of course, the battery housing formed by the top cover 10 and housing 30 can be of various shapes, such as a cylinder, a cuboid, etc.

[0065] Figure 3This is a schematic diagram of the structure of a battery module according to some embodiments of this application. In the battery device 100, there can be multiple battery cells 20, which can be connected in series, parallel, or in a mixed manner. A mixed connection means that multiple battery cells 20 are connected in both series and parallel. Multiple battery cells 20 can be directly connected in series, parallel, or in a mixed manner, and then the whole assembly of multiple battery cells 20 is housed in a housing. Of course, the battery device 100 can also be in the form of multiple battery cells 20 first connected in series, parallel, or in a mixed manner to form a battery module 400, and then multiple battery modules 400 are connected in series, parallel, or in a mixed manner to form a whole and housed in a housing. The battery device 100 may also include other structures. For example, the battery device 100 may also include a busbar component for realizing the electrical connection between multiple battery cells 20.

[0066] Each battery cell 20 can be a secondary battery cell or a primary battery cell; it can also be a lithium-sulfur battery cell, a sodium-ion battery cell, or a magnesium-ion battery cell, but is not limited to these. The battery cell 20 can be cylindrical, flat, cuboid, or other shapes.

[0067] Figure 4 This is an exploded structural diagram of a battery cell according to some embodiments of this application. The end cap 21 is a component that covers the opening of the housing 22 to isolate the internal environment of the battery cell 20 from the external environment. The shape of the end cap 21 can be adapted to the shape of the housing 22 to fit it. Optionally, the end cap 21 can be made of a material with a certain hardness and strength (such as aluminum alloy), so that the end cap 21 is less prone to deformation under pressure and impact, enabling the battery cell 20 to have higher structural strength and improved safety performance. Functional components such as electrode terminals 26 can be provided on the end cap 21. The electrode terminals 26 can be used to electrically connect with the electrode assembly 23 for outputting or inputting electrical energy into the battery cell 20. In some embodiments, the end cap 21 can also be provided with a pressure relief mechanism for releasing internal pressure when the internal pressure or temperature of the battery cell 20 reaches a threshold. The material of the end cap 21 can also be various, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc., and this application does not impose special limitations on this. In some embodiments, an insulating element may be provided on the inner side of the end cap 21. The insulating element can be used to isolate the electrical connection components within the housing 22 from the end cap 21 to reduce the risk of short circuits. For example, the insulating element may be made of plastic, rubber, etc.

[0068] Battery cells produce hydrogen gas during operation. If this hydrogen gas accumulates inside the cell, it increases the internal pressure. When the pressure exceeds the cell's casing's tolerance limit, it can cause the casing to rupture or even explode. Incorporating hydrogen-absorbing materials inside the battery cell can reduce the hydrogen content and lower safety risks. However, this material also reduces the cell's energy density.

[0069] To address the aforementioned technical problems, this application provides a battery cell in which the negative electrode current collector protrudes along a first direction from the positive electrode active material layer to reduce the risk of short circuits. The hydrogen absorption layer can absorb the gas generated during the operation of the battery cell. By placing the hydrogen absorption layer on the elongated negative electrode current collector, the utilization of the internal space of the battery cell can be improved, thereby increasing the energy density of the battery cell.

[0070] Figure 5 This is a partial cross-sectional schematic diagram of an electrode assembly according to some embodiments of this application.

[0071] like Figure 5 As shown, in a first aspect, embodiments of this application provide a battery cell 20, which includes a housing 24, an electrode assembly 23, and a hydrogen absorption layer 40. The electrode assembly 23 is disposed inside the housing 24 and includes a positive electrode 50 and a negative electrode 60. The positive electrode 50 includes a positive current collector 51 and a positive active material layer 52 disposed on the positive current collector 51. The negative electrode 60 includes a negative current collector 61, which protrudes from the positive active material layer 52 along a first direction X, perpendicular to the thickness direction Y of the negative current collector 61. The hydrogen absorption layer 40 is disposed on the portion of the negative current collector 61 that protrudes from the positive active material layer 52 along the first direction X.

[0072] The battery cell 20 can be a lithium metal battery cell 20, a sodium metal battery cell 20, a lithium-ion battery cell 20, or a sodium-ion battery cell 20.

[0073] A separator 70 is disposed between the positive electrode 50 and the negative electrode 60. The positive electrode current collector 51 can be made of aluminum foil, which has good conductivity and can meet the electron conduction requirements of the positive electrode active material during charging and discharging. The material of the positive electrode active material layer 52 can be lithium cobalt oxide, lithium iron phosphate, lithium manganese oxide, etc. The negative electrode current collector 61 can be made of copper foil, which has good conductivity and high conductivity, and can effectively collect and conduct electrons.

[0074] For example, the lithium metal in the lithium metal battery cell 20 is chemically very reactive. During the charging and discharging process of the battery cell 20, lithium dendrites are easily formed during the deposition and dissolution process on the surface of the negative electrode 60. If the negative electrode 60 does not have enough space, lithium dendrites are more likely to grow and pierce the separator, leading to a short circuit inside the battery cell 20. The first direction X can be the width direction of the negative electrode current collector 61. Therefore, by making the negative electrode current collector 61 protrude from the positive electrode active material layer 52 along the first direction X, that is, the width of the negative electrode current collector 61 is longer than the width of the positive electrode active material layer 52, more space can be provided for lithium deposition, which reduces the short circuit risk caused by lithium dendrite growth to a certain extent. Similarly, for other sodium metal battery cells 20, lithium-ion battery cells 20, or sodium-ion battery cells 20, making the negative electrode current collector 61 protrude from the positive electrode active material layer 52 along the first direction X can reduce the short circuit risk.

[0075] The material of the hydrogen absorption layer 40 can include magnesium alloy, titanium alloy, or lanthanum alloy, etc. By utilizing the portion of the negative electrode current collector 61 that extends beyond the positive electrode active material layer 52, and coating this extended portion with the hydrogen absorption layer 40, the risk of lithium absorption and short circuits can be reduced. Furthermore, the hydrogen absorption layer 40 can utilize the existing space within the battery cell 20 to absorb generated hydrogen gas promptly, preventing hydrogen accumulation within the battery cell 20 and maintaining the internal pressure within a suitable range. Since a portion of the negative electrode current collector 61 protrudes beyond the positive electrode active material layer 52, utilizing this space for the hydrogen absorption layer 40 does not occupy excessive additional space within the limited internal space of the battery cell 20, thus achieving the hydrogen absorption function without affecting the battery's energy density.

[0076] In the above scheme, by protruding the negative electrode current collector 61 along the first direction X out of the positive electrode active material layer 52, the risk of short circuit is reduced. The hydrogen absorption layer 40 can absorb the gas generated during the operation of the battery cell 20. By placing the hydrogen absorption layer 40 on the extended negative electrode current collector 61, the utilization of the internal space of the battery cell 20 can be improved, and the energy density of the battery cell 20 can be increased.

[0077] Figure 6 This is a partial cross-sectional schematic diagram of an electrode assembly according to other embodiments of this application.

[0078] like Figure 6 As shown, in some embodiments, the negative electrode current collector 61 has hydrogen absorption layers 40 on both opposite sides along the thickness direction Y.

[0079] Along the first direction X, where the negative electrode current collector 61 extends beyond the positive electrode active material layer 52, both surfaces of the negative electrode current collector 61 are coated with hydrogen-absorbing layers 40, achieving double-sided coating. This double-sided hydrogen-absorbing design increases the effective hydrogen absorption area, ensuring timely absorption regardless of the direction from which hydrogen is generated or diffuses. For example, inside the battery cell 20, if hydrogen generated by a chemical reaction is evenly distributed around the negative electrode current collector 61, the hydrogen-absorbing layers 40 on both sides can function simultaneously, more efficiently reducing the hydrogen content inside the battery cell 20 compared to single-sided hydrogen absorption.

[0080] From the perspective of hydrogen absorption kinetics, the double-sided hydrogen absorption layer 40 provides more hydrogen absorption sites. Just as increasing the contact area of ​​reactants in a chemical reaction can accelerate the reaction rate, more hydrogen absorption sites allow the hydrogen absorption process to proceed more quickly. This is especially important for situations where large amounts of hydrogen may be generated rapidly (such as when an abnormal reaction occurs in the battery), as it can quickly reduce the hydrogen concentration inside the battery cell 20 and reduce safety hazards.

[0081] In the above scheme, hydrogen absorption efficiency can be improved by setting hydrogen absorption layers 40 on both sides of the negative electrode current collector 61.

[0082] Figure 7 This is a partial cross-sectional schematic diagram of an electrode assembly according to some embodiments of this application.

[0083] like Figure 7 As shown, in some embodiments, the negative electrode sheet 60 further includes a negative electrode active material layer 62 disposed on the negative electrode current collector 61, and the thickness of the hydrogen absorption layer 40 along the thickness direction Y is less than or equal to the thickness of the negative electrode active material layer 62.

[0084] The battery cell 20 with the negative electrode active material layer 62 is either a lithium-ion battery cell 20 or a sodium-ion battery cell 20. The material of the negative electrode active material layer 62 can be natural graphite, artificial graphite, elemental silicon, silicon-carbon composite material, lithium titanate, etc. The negative electrode active material layer 62 is a key part participating in the battery charging and discharging reaction, and its main function is to store and release lithium ions (taking a lithium-ion battery as an example).

[0085] To ensure sufficient capacity and good performance of the battery cell 20, a negative electrode active material layer 62 of a certain thickness is required. The main function of the hydrogen absorption layer 40 is to absorb any hydrogen that may be generated, preventing it from harming the battery cell 20. Designing the thickness of the hydrogen absorption layer 40 to be less than or equal to the thickness of the negative electrode active material layer 62 can, to a certain extent, ensure that the hydrogen absorption requirements are met without excessively occupying the internal space of the battery cell 20 used for energy storage.

[0086] In the above scheme, by setting the thickness of the hydrogen absorption layer 40 to not exceed the thickness of the negative electrode active material layer 62, the energy density of the electrode assembly 23 can be maintained.

[0087] If the electrode assembly 23 is a wound structure, setting the thickness of the hydrogen absorption layer 40 to be less than or equal to the thickness of the negative electrode active material layer 62 will not affect the winding of the electrode assembly 23.

[0088] In some embodiments, the battery cell 20 is a lithium metal battery cell 20 or a sodium metal battery cell 20.

[0089] The negative electrode current collector 61 of either the lithium metal battery cell 20 or the sodium metal battery cell 20 can be directly used as the negative electrode sheet 60. This type of battery cell 20 can also be called a "negative electrode-free battery cell 20". During charging, lithium metal is formed by the deposition of lithium ions extracted from the positive electrode active material onto the negative electrode current collector 61 (i.e., the negative electrode active material is lithium metal), or sodium metal is formed by the deposition of sodium ions extracted from the positive electrode active material onto the negative electrode current collector 61 (i.e., the negative electrode active material is sodium metal).

[0090] The negative electrode-less metal battery system produces nearly 90% hydrogen, which, compared to other battery systems that primarily produce carbon dioxide, makes the battery cell 20 more vulnerable to damage from air and sparks upon failure, potentially leading to open flames. Furthermore, during operation, the large amount of gas present in the battery cell 20 can cause expansion at the internal interfaces, hindering ion transport and other performance-impairing consequences. Therefore, it is crucial to incorporate a hydrogen-absorbing layer 40 within the lithium metal or sodium metal battery cell 20.

[0091] In the above scheme, the lithium metal battery cell 20 or the sodium metal battery cell 20 has a high theoretical energy density and high safety.

[0092] Figure 8 This is a partial cross-sectional schematic diagram of an electrode assembly in some embodiments of this application.

[0093] like Figure 8 As shown, in some embodiments, the negative electrode 60 further includes a conductive film layer 63 disposed on the negative electrode current collector 61.

[0094] The conductive film layer 63 can be deposited on at least one surface of the negative electrode current collector 61 by methods such as physical vapor deposition, spin coating, electroplating, and chemical vapor deposition.

[0095] During the charging process of the electrodeless battery cell 20, lithium ions are released from the positive electrode active material and deposited on the negative electrode current collector 61 to form lithium metal. The conductive film layer 63 can guide the more uniform deposition of lithium ions. This is because the conductive film layer 63 typically has good conductivity and ion conductivity, which can provide more deposition sites for lithium ions, preventing excessive accumulation and deposition of lithium ions in local areas. For example, similar to how a uniform conductive substrate allows for uniform deposition of metal ions during electroplating, the conductive film layer 63 plays a similar role on the negative electrode current collector 61, thereby reducing the formation of lithium dendrites.

[0096] During the operation of the battery cell 20, electrons need to be effectively conducted between the negative electrode current collector 61 and the deposited lithium metal. The conductive film layer 63, as a good electronic conductor, ensures rapid electron transport. It connects the negative electrode current collector 61 and the lithium metal, acting like an "electronic bridge" to facilitate smoother electron conduction during charging and discharging. For example, when the battery cell 20 discharges, the lithium metal loses electrons to become lithium ions. These electrons need to be conducted to the external circuit through the conductive film layer 63 and the negative electrode current collector 61. The conductive film layer 63 can reduce the resistance of electron transport, thereby improving battery performance.

[0097] In the above scheme, by setting a conductive film layer 63 on the negative electrode current collector 61, the conductivity efficiency of the battery cell 20 can be improved.

[0098] Optionally, the length of the conductive film layer 63 along the first direction X may also exceed the length of the positive electrode active material layer 52 along the first direction X, in order to reduce the lithium plating effect and reduce short circuit phenomenon.

[0099] In some embodiments, the battery cell 20 is a sodium-ion battery cell 20 or a sodium metal battery cell 20, which has higher energy density and better conductivity. Moreover, sodium is cheaper than lithium, which can reduce costs.

[0100] Figure 9 This is a cross-sectional schematic diagram of a battery cell according to some embodiments of this application.

[0101] like Figure 9 As shown, in some embodiments, the housing 24 includes a top wall 241 and a bottom wall 242, the bottom wall 242 being used to support the electrode assembly 23, and the hydrogen absorption layer 40 being located on the side of the negative electrode current collector 61 near the top wall 241.

[0102] The outer casing 24 may include a housing 22 and an end cap 21. The housing 22 has an opening, and the end cap 21 covers the opening. A top wall 241 is located at the end cap 21, and a bottom wall 242 is located at the bottom of the housing 22. After the battery cell 20 is placed, the top wall 241 faces upward and the bottom wall 242 faces downward. There is a certain gap between the electrolyte and the top wall 241.

[0103] In the above scheme, by placing the hydrogen absorption layer 40 on the side of the negative electrode current collector 61 close to the top wall 241 of the outer shell 24, the hydrogen absorption layer 40 can be prevented from contacting the electrolyte to a certain extent, thereby giving full play to the role of the hydrogen absorption layer 40.

[0104] In some embodiments, the housing 24 further includes a side wall 243, the top wall 241 and the bottom wall 242 are connected through the side wall 243, and the battery cell 20 further includes an electrode terminal 26 disposed on the side wall 243, the electrode terminal 26 being electrically connected to the electrode assembly 23.

[0105] The electrode terminal 26 is connected to the tab of the electrode assembly 23, or connected to the tab via an adapter. The positive electrode terminal 26 and the negative electrode terminal 26 can be respectively disposed on different side walls 243, for example, one is disposed on the left side wall 243 and the other is disposed on the right side wall 243.

[0106] When the electrode terminals 26 are located on the top wall 241 of the housing 24, if the end cap 21 is subjected to external forces such as squeezing or collision during use or transportation of the battery cell 20, the terminals of the electrodes located on the end cap 21 are very likely to deform or shift, thereby reducing the spacing between the electrodes and increasing the risk of short circuit. However, placing the electrode terminals 26 on the side wall 243 of the housing 24 can, to some extent, avoid the short circuit problem caused by the deformation of the end cap 21 under force.

[0107] If the electrode terminal 26 is located on the top wall 241, a larger space needs to be reserved when arranging the batteries to avoid interference between the positive electrode terminal 26 and the negative electrode terminal 26. However, by setting the positive electrode terminal 26 and the negative electrode terminal 26 on different side walls 243, the design of the battery cell 20 can be made more compact.

[0108] In the above scheme, by setting the electrode terminal 26 on the side wall 243, the safety and space utilization of the battery cell 20 can be increased.

[0109] Figure 10 This is a partial cross-sectional schematic diagram of an electrode assembly in some embodiments of this application.

[0110] like Figure 10 As shown, in some embodiments, the negative electrode current collector 61 includes a first current collector 611, a second current collector 612, and a negative electrode tab 613. The second current collector 612 is respectively provided on opposite sides of the first current collector 611 along the first direction X, and a hydrogen absorption layer 40 is provided on at least one of the second current collectors 612. The negative electrode tab 613 is provided on one side of one of the second current collectors 612 away from the first current collector 611.

[0111] If the battery cell 20 is a lithium-ion battery cell 20 or a sodium-ion battery cell 20, a negative electrode active material layer 62 can be provided on the first current collector 611. If the battery cell 20 is a lithium metal battery cell 20 or a sodium metal battery cell 20, a conductive film layer 63 can be provided on the first current collector 611.

[0112] When preparing the negative electrode 60, multiple negative electrode tabs 613 are cut along the length of the electrode, and then the electrode is cut into multiple negative electrode sheets 60 along the width. Therefore, the hydrogen absorption layer 40 is disposed on one side or the opposite side of the negative electrode tab 613, so that the hydrogen absorption layer 40 of multiple negative electrode sheets 60 can be continuously coated first, and then when the negative electrode sheets 60 are cut, multiple negative electrode sheets 60 coated with the hydrogen absorption layer 40 can be obtained.

[0113] In the above scheme, by placing the hydrogen absorption layer 40 on one side of the negative electrode tab 613 or on the opposite side of the negative electrode tab 613, the continuous coating of the hydrogen absorption layer 40 can be achieved, which facilitates the process preparation.

[0114] In some embodiments, the hydrogen absorption layer 40 is provided only in the second current collector 612 near the negative electrode tab 613.

[0115] The negative electrode tab 613 is positioned toward the top wall 241 of the outer casing 24, and the electrode terminal 26 is also positioned on the top wall 241. The negative electrode tab 613 is connected to the electrode terminal 26 on the top wall 241, or connected via an adapter.

[0116] In the above scheme, by limiting the hydrogen absorption layer 40 to a position close to the negative electrode tab 613, the negative electrode tab 613 can be set facing upwards, and the hydrogen absorption layer 40 will not be wetted by the electrode liquid, thereby ensuring the effectiveness of the hydrogen absorption layer 40 to a certain extent.

[0117] Figure 11 This is a partial cross-sectional schematic diagram of an electrode assembly in some embodiments of this application.

[0118] like Figure 11 As shown, in some embodiments, along the first direction X, the width of the hydrogen absorption layer 40 is L1, and the width of the negative electrode current collector 61 is L2, where L1 and L2 satisfy: 0.007≤L1 / L2≤0.145.

[0119] L1 / L2 can be any value between 0.007 and 0.145. For example, L1 / L2 can be 0.007, 0.009, 0.01, 0.05, 0.1, 0.135, or 0.145, etc.

[0120] In the above scheme, by limiting the width ratio of the hydrogen absorption layer 40 to the negative electrode current collector 61 within a suitable range, the hydrogen absorption effect can be guaranteed to a certain extent without occupying too much space in the battery cell 20, thereby improving the battery energy density.

[0121] In some embodiments, L1 and L2 satisfy: 0.03≤L1 / L2≤0.1.

[0122] L1 / L2 can be any value between 0.03 and 0.1. For example, L1 / L2 can be 0.03, 0.05, 0.06, 0.07, 0.08, 0.09, or 0.1, etc.

[0123] In the above scheme, by further limiting the width ratio of the hydrogen absorption layer 40 to the negative electrode current collector 61, a balance between hydrogen absorption effect and energy density can be further achieved.

[0124] In some embodiments, the areal density of the hydrogen absorption layer 40 is d, where d satisfies: 0.3 mg / cm³ 2 ≤d≤13mg / cm 2 .

[0125] The areal density d of the hydrogen-absorbing layer 40 can be 0.3 mg / cm³. 2 -13 mg / cm 2 Any value in the range. For example, the areal density d of the hydrogen-absorbing layer 40 can be 0.3 mg / cm³. 2 0.5 mg / cm 2 1mg / cm 2 3mg / cm 2 6mg / cm 2 8mg / cm 2 10mg / cm 2 Or 13mg / cm 2 wait.

[0126] Areal density refers to the mass per unit area. For hydrogen-absorbing layer 40, areal density (d) represents the mass (milligrams) present on the surface of hydrogen-absorbing layer 40 per square centimeter. For example, if the areal density of hydrogen-absorbing layer 40 is 1 mg / cm³... 2 That means that the mass of the hydrogen-absorbing layer of 40 per square centimeter is milligrams.

[0127] The areal density is related to the hydrogen absorption capacity of the hydrogen-absorbing layer 40. Generally speaking, within a reasonable range, the higher the areal density, the more hydrogen-absorbing material may be present in the hydrogen-absorbing layer 40, and the stronger its potential hydrogen absorption capacity.

[0128] In the above scheme, by controlling the range of the areal density of the hydrogen absorption layer 40, it is easier to control the thickness of the hydrogen absorption layer 40, so that the coating of the hydrogen absorption layer 40 is uniform and will not affect the energy density of the battery cell 20.

[0129] In some embodiments, d satisfies: 1.3 mg / cm³ 2 ≤d≤6.5mg / cm 2 .

[0130] The areal density d of the hydrogen-absorbing layer 40 can be 1.3 mg / cm³. 2 -6.5mg / cm 2 Any value in the range. For example, the areal density d of the hydrogen-absorbing layer 40 can be 1.3 mg / cm³. 2 2mg / cm 2 2.5 mg / cm 2 3.1 mg / cm 2 4mg / cm 2 4.5 mg / cm 2 5mg / cm 2 Or 6.5 mg / cm 2 wait

[0131] In the above scheme, by further limiting the range of areal density, the coating of the hydrogen absorption layer 40 can be made more uniform, and the winding of the electrode assembly 23 can be made more efficient.

[0132] In some embodiments, the material of the hydrogen absorption layer 40 includes any one of a magnesium alloy, a titanium alloy, or a lanthanum alloy.

[0133] Magnesium alloys have a high hydrogen adsorption capacity. For example, under certain temperature and pressure conditions, magnesium alloys can quickly combine with hydrogen gas and store it, thereby reducing the hydrogen content inside the battery. Moreover, magnesium alloys have a relatively low density, so using this material as a hydrogen-absorbing layer 40 in a battery will not significantly increase the weight of the battery cell 20.

[0134] Titanium alloys have excellent chemical stability and can resist corrosion and chemical reactions within the electrolyte environment and operating temperature range of batteries.

[0135] Lanthanum alloys typically have a high hydrogen absorption capacity, capable of absorbing large amounts of hydrogen gas. Lanthanum has a strong affinity for hydrogen, and lanthanum alloys can form various hydrides under certain conditions.

[0136] In the above scheme, by selecting the above material as the material of the hydrogen absorption layer 40, the hydrogen absorption effect can be improved.

[0137] Secondly, embodiments of this application also provide a battery device 100, including a battery cell 20 of any of the above embodiments.

[0138] Thirdly, embodiments of this application also provide an electrical device, including the aforementioned battery device 100, which is used to provide electrical energy.

[0139] According to some embodiments of this application, this application provides a battery cell 20, including a casing 24, an electrode assembly 23, and a hydrogen absorption layer 40. The electrode assembly 23 is disposed inside the casing 24 and includes a positive electrode 50 and a negative electrode 60. The positive electrode 50 includes a positive current collector 51 and a positive active material layer 52 disposed on the positive current collector 51. The negative electrode 60 includes a negative current collector 61, which protrudes from the positive active material layer 52 along a first direction X, perpendicular to the thickness direction Y of the negative current collector 61. The hydrogen absorption layer 40 is disposed on the portion of the negative current collector 61 that protrudes from the positive active material layer 52 along the first direction X. The battery cell 20 is a lithium metal battery cell 20 or a sodium metal battery cell 20.

[0140] 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 in that, include: shell; An electrode assembly is disposed inside the housing. The electrode assembly includes a positive electrode sheet and a negative electrode sheet. The positive electrode sheet includes a positive current collector and a positive active material layer disposed on the positive current collector. The negative electrode sheet includes a negative current collector. The negative current collector protrudes from the positive active material layer along a first direction, which is perpendicular to the thickness direction of the negative current collector. A hydrogen absorption layer is disposed on the portion of the negative electrode current collector that protrudes from the positive electrode active material layer along the first direction.

2. The battery cell according to claim 1, characterized in that, The negative electrode current collector has hydrogen absorption layers on both sides along the thickness direction.

3. The battery cell according to claim 1, characterized in that, The negative electrode sheet also includes a negative electrode active material layer disposed on the negative electrode current collector, wherein the thickness of the hydrogen absorption layer is less than or equal to the thickness of the negative electrode active material layer along the thickness direction.

4. The battery cell according to claim 1, characterized in that, The battery cell is a lithium metal battery cell or a sodium metal battery cell.

5. The battery cell according to claim 4, characterized in that, The negative electrode sheet also includes a conductive film layer disposed in the negative electrode current collector.

6. The battery cell according to claim 1, characterized in that, The battery cell is a sodium-ion battery cell or a sodium metal battery cell.

7. The battery cell according to claim 1, characterized in that, The housing includes a top wall and a bottom wall, the bottom wall being used to support the electrode assembly, and the hydrogen absorption layer being located on the side of the negative electrode current collector near the top wall.

8. The battery cell according to claim 7, characterized in that, The housing also includes a side wall, the top wall and the bottom wall are connected through the side wall, and the battery cell also includes an electrode terminal disposed on the side wall, the electrode terminal being electrically connected to the electrode assembly.

9. The battery cell according to claim 1, characterized in that, The negative electrode current collector includes: First collection section; The second current collection section is provided on opposite sides of the first current collection section along the first direction, and the hydrogen absorption layer is provided on at least one of the second current collection sections; The negative electrode tab is disposed on one side of one of the second current collectors, away from the first current collector.

10. The battery cell according to claim 9, characterized in that, The hydrogen absorption layer is provided only in the second current collector section near the negative electrode tab.

11. The battery cell according to any one of claims 1-10, characterized in that, Along the first direction, the width of the hydrogen absorption layer is L1, and the width of the negative electrode current collector is L2, wherein L1 and L2 satisfy: 0.007≤L1 / L2≤0.

145.

12. The battery cell according to claim 11, characterized in that, The L1 and L2 satisfy the condition: 0.03≤L1 / L2≤0.

1.

13. The battery cell according to any one of claims 1-10, characterized in that, The areal density of the hydrogen-absorbing layer is d, and d satisfies: 0.3 mg / cm³ 2 ≤d≤13mg / cm 2 .

14. The battery cell according to claim 13, characterized in that, The d satisfies: 1.3 mg / cm³ 2 ≤d≤6.5mg / cm 2 .

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

16. An electrical appliance, characterized in that, Includes the battery device according to claim 15, the battery device being used to provide electrical energy.

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