Battery cell, battery, and electric device

Abstract

The application provides a battery monomer, a battery and a power utilization device. The battery monomer comprises a shell, an electrode assembly, a first electrolyte and a liquid supplementing assembly. The shell has a containing cavity. The electrode assembly is arranged in the containing cavity. The first electrolyte is contained in the containing cavity and is used for infiltrating the electrode assembly. The liquid supplementing assembly is used for storing a second electrolyte and releasing the second electrolyte into the first electrolyte in response to a predetermined condition. In the battery monomer provided by the embodiment of the application, the first electrolyte is gradually consumed with the increase of the cycle number, and when the predetermined condition is triggered, the liquid supplementing assembly can release the stored second electrolyte into the first electrolyte to supplement the electrolyte required by the normal charging and discharging of the battery monomer in response to the predetermined condition, effectively alleviating the lithium precipitation phenomenon caused by the reduction of the electrolyte amount, so that the safety performance of the battery monomer can be improved, and the cycle performance of the battery monomer can also be improved.

Description

Technical Field

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

[0002] As one of the most watched new energy sources, batteries have excellent properties such as high energy density, high power, and rechargeability, and have been widely used in various fields such as consumer electronics and power equipment.

[0003] However, in related technologies, the safety and cycle performance of batteries decline rapidly with increasing cycle count, affecting their development prospects. Summary of the Invention

[0004] This application provides a battery cell, a battery, and an electrical device that can improve the safety performance of the battery cell while also improving its cycle performance.

[0005] In a first aspect, embodiments of this application provide a battery cell, including a housing, an electrode assembly, a first electrolyte, and a replenishment assembly. The housing has a receiving cavity. The electrode assembly is disposed within the receiving cavity. The first electrolyte is contained within the receiving cavity and is used to wet the electrode assembly. The replenishment assembly is used to store a second electrolyte, and to release the second electrolyte into the first electrolyte in response to predetermined conditions.

[0006] In the battery cell provided in this application embodiment, as the number of cycles increases, the first electrolyte is gradually consumed. When a predetermined condition is triggered, the electrolyte replenishment component can respond to the predetermined condition and release the stored second electrolyte into the first electrolyte to replenish the electrolyte required for normal charging and discharging of the battery cell. This effectively alleviates the lithium plating phenomenon caused by the reduction of electrolyte volume. In this way, the safety performance of the battery cell can be improved, and the cycle performance of the battery cell can also be improved.

[0007] In any of the foregoing embodiments of the first aspect of this application, the electrolyte replenishment assembly includes a first replenishment element having a sealed first reservoir for storing the second electrolyte. The wall of the first reservoir is capable of rupturing under predetermined conditions to release the second electrolyte into the first electrolyte. The predetermined conditions include an aging time T of the wall of the first reservoir. The first replenishment element has a sealed first reservoir for storing the second electrolyte, and the wall of the first reservoir automatically ruptures at a suitable aging time T to release the second electrolyte into the first electrolyte. This allows for timely replenishment of the electrolyte, which can improve the safety performance of the battery cell and also help improve its cycle performance.

[0008] In any of the foregoing embodiments of the first aspect of this application, the shape of the first fluid replenishment member is selected from any one of the shapes of circle, gourd, ellipse, and square. Selecting any one of these shapes for the first fluid replenishment member facilitates its installation into the housing.

[0009] In any of the foregoing embodiments of the first aspect of this application, the volume V1 of the first electrolyte storage chamber and the capacity A of the battery cell satisfy the following relationship: 0.05 mL / Ah ≤ V1 / A ≤ 0.2 mL / Ah. Since the volume V1 of the first electrolyte storage chamber and the capacity A of the battery cell satisfy the above relationship, the amount of second electrolyte to be added can be reasonably matched, which can further improve the cycle performance of the battery cell.

[0010] In any of the foregoing embodiments of the first aspect of this application, the volume V1 of the first electrolyte storage chamber is in the range of 2.5 mL to 60 mL. Setting the volume V1 of the first electrolyte storage chamber within this suitable range allows it to store an appropriate amount of the second electrolyte and, at a suitable aging time T, release an appropriate amount of the second electrolyte into the first electrolyte, thereby further improving the cycle performance of the battery cell.

[0011] In any of the foregoing embodiments of the first aspect of this application, the wall material of the first electrolyte storage chamber includes at least one selected from polyethylene terephthalate, polycarbonate, polyvinyl chloride, polyvinylidene fluoride, polyethylene, and polyvinylidene chloride. The aforementioned materials comprising the wall material of the first electrolyte storage chamber enable the first electrolyte storage chamber to automatically rupture at a suitable aging time T, releasing the second electrolyte. Furthermore, the aforementioned materials also give the first electrolyte replenishment component a certain degree of elasticity, reducing the risk of damage to the battery cells during movement.

[0012] In any of the foregoing embodiments of the first aspect of this application, the aging time T of the cavity wall of the first liquid storage cavity and the thickness D1 of the cavity wall of the first liquid storage cavity satisfy the following relationship: T = -0.0005D1 2 +0.1648D1-2.0971, where the aging time T of the cavity wall of the first liquid storage chamber is in years, and the thickness D1 of the cavity wall of the first liquid storage chamber is in μm. The aging time T of the cavity wall of the first liquid storage chamber and the thickness D1 of the cavity wall of the first liquid storage chamber satisfy the above relationship. In this way, the aging time T of the cavity wall of the first liquid storage chamber can be controlled by the thickness D1 of the cavity wall of the first liquid storage chamber, so that it can adapt to different types of battery cells, automatically rupture at an appropriate time, and release the second electrolyte into the first electrolyte, thereby improving the safety performance and cycle performance of the battery cell.

[0013] In any of the foregoing embodiments of the first aspect of this application, the aging time T of the cavity wall of the first liquid storage chamber is in the range of 1 to 10 years. Setting the aging time T of the cavity wall of the first liquid storage chamber within the above range can help the first replenishment element to replenish electrolyte to the battery cell in a timely manner, thereby improving the cycle performance of the battery cell.

[0014] In any of the foregoing embodiments of the first aspect of this application, the aging time T of the cavity wall of the first liquid storage chamber is in the range of 5 to 8 years. Setting the aging time T of the cavity wall of the first liquid storage chamber within the above range can help the first replenishment element to replenish electrolyte to the battery cell in a timely manner, thereby improving the cycle performance of the battery cell.

[0015] In any of the foregoing embodiments of the first aspect of this application, the thickness D1 of the cavity wall of the first liquid storage chamber is in the range of 20 μm to 100 μm. Setting the thickness D1 of the cavity wall of the first liquid storage chamber within the above-mentioned suitable range can help the first liquid replenishment element to automatically break at the corresponding aging time T and release the second electrolyte into the first electrolyte in a timely manner.

[0016] In any of the foregoing embodiments of the first aspect of this application, the thickness D1 of the cavity wall of the first liquid storage chamber is in the range of 50 μm to 100 μm. Setting the thickness D1 of the cavity wall of the first liquid storage chamber within the above-mentioned suitable range can further help the first liquid replenishment element to automatically rupture at the corresponding aging time T and quickly release the second electrolyte into the first electrolyte.

[0017] In any of the foregoing embodiments of the first aspect of this application, the second electrolyte stored in the first storage chamber includes at least one additive selected from vinylene carbonate, fluoroethylene carbonate, carboxylic acid ester, sulfate ester, and sulcolone. The additives included in the second electrolyte can reduce the occurrence of side reactions and thus reduce gas generation, thereby reducing the expansion of the battery cells.

[0018] In any of the foregoing embodiments of the first aspect of this application, the electrolyte replenishment assembly includes a second replenishment element. The second replenishment element has a sealed second reservoir for storing the second electrolyte. The wall of the second reservoir is capable of rupturing under predetermined conditions to release the second electrolyte into the first electrolyte. The predetermined conditions include a maximum stress P borne by the wall of the second reservoir. The second replenishment element has a sealed second reservoir for storing the second electrolyte. The wall of the second reservoir automatically ruptures under the maximum stress P to release the second electrolyte into the first electrolyte. This allows for timely replenishment of the electrolyte, which can improve the safety performance of the battery cell and also help improve the cycle performance of the battery cell.

[0019] In any of the foregoing embodiments of the first aspect of this application, the shape of the second fluid replenishment member is selected from any one of the shapes of circle, gourd, ellipse, and square. Selecting any one of these shapes for the second fluid replenishment member facilitates its installation within the housing.

[0020] In any of the foregoing embodiments of the first aspect of this application, the volume V2 of the second electrolyte storage chamber and the capacity A of the battery cell satisfy the following relationship: 0.05 mL / Ah ≤ V2 / A ≤ 0.2 mL / Ah. This relationship between the volume V2 of the second electrolyte storage chamber and the capacity A of the battery cell allows for reasonable matching of the amount of second electrolyte to be added, further improving the cycle performance of the battery cell.

[0021] In any of the foregoing embodiments of the first aspect of this application, the volume V2 of the second electrolyte storage chamber is in the range of 2.5 mL to 60 mL. The volume V2 of the second electrolyte storage chamber is set within the aforementioned suitable range, enabling it to store an appropriate amount of the second electrolyte, and to automatically rupture under maximum stress P, thereby releasing an appropriate amount of the second electrolyte into the first electrolyte, further improving the cycle performance of the battery cell.

[0022] In any of the foregoing embodiments of the first aspect of this application, the maximum stress P borne by the wall of the second liquid storage chamber and the thickness D2 of the wall of the second liquid storage chamber satisfy the following relationship: P = 0.0945D2 2 +3.7533D2+184.51, where the maximum stress P borne by the wall of the second liquid storage chamber is in kgf, and the thickness D2 of the wall of the second liquid storage chamber is in μm. The maximum stress P borne by the wall of the second liquid storage chamber and the thickness D2 of the wall of the second liquid storage chamber satisfy the above relationship. In this way, the maximum stress P borne by the wall of the second liquid storage chamber can be controlled by the thickness D2 of the wall of the second liquid storage chamber, so that it can adapt to different types of battery cells, automatically rupture under a suitable maximum stress P, and release the second electrolyte into the first electrolyte, thereby improving the safety performance and cycle performance of the battery cell.

[0023] In any of the foregoing embodiments of the first aspect of this application, the maximum stress P borne by the cavity wall of the second electrolyte storage chamber is in the range of 200 kgf to 1500 kgf. Setting the maximum stress P borne by the cavity wall of the second electrolyte storage chamber within this suitable range enables the second electrolyte replenishment component to rupture at different stages of the battery cell, releasing the second electrolyte into the first electrolyte, thereby meeting the electrolyte requirements of the battery cell at different stages and improving the safety and cycle performance of the battery cell.

[0024] In any of the foregoing embodiments of the first aspect of this application, the maximum stress P borne by the wall of the second liquid storage chamber is in the range of 500 kgf-1100 kgf.

[0025] In any of the foregoing embodiments of the first aspect of this application, the thickness D2 of the cavity wall of the second liquid storage chamber is in the range of 20μm-100μm. Setting the thickness D2 of the cavity wall of the second liquid storage chamber within this suitable range allows the second liquid storage chamber to withstand different maximum stresses P and causes the second replenishing element to rupture at different stages, thereby releasing the second electrolyte into the first electrolyte.

[0026] In any of the foregoing embodiments of the first aspect of this application, the thickness D2 of the cavity wall of the second liquid storage cavity is in the range of 50μm-100μm.

[0027] In any of the foregoing embodiments of the first aspect of this application, the second electrolyte stored in the second reservoir includes at least one additive selected from vinylene carbonate, fluoroethylene carbonate, carboxylic acid ester, sulfate ester, and sulcolone. The additives included in the second electrolyte can reduce the occurrence of side reactions and thus reduce gas generation, thereby reducing the expansion of the battery cells.

[0028] In any of the foregoing embodiments of the first aspect of this application, the replenishment component is located between the inner wall of the housing and the electrode assembly. The replenishment component is positioned between the housing, the inner wall, and the electrode assembly, which allows the replenishment component to rapidly release the second electrolyte into the first electrolyte upon responding to predetermined conditions, and also reduces external damage to the replenishment component.

[0029] In any of the foregoing embodiments of the first aspect of this application, the housing includes a bottom wall, two first side walls, and two second side walls. The two first side walls are disposed opposite each other on the bottom wall along a first direction, and the electrolyte replenishment assembly is located between the first side walls and the electrode assembly. The two second side walls are disposed opposite each other on the bottom wall along a second direction, and the second side walls are connected between the two first side walls to form the receiving cavity, and the area of ​​the second side walls is smaller than the area of ​​the first side walls. The first direction is perpendicular to the second direction. The electrolyte replenishment assembly is located between the first side walls and the electrode assembly, and the area of ​​the first side walls is larger than the area of ​​the second side walls. This allows the electrolyte replenishment assembly to be designed with a larger volume to accommodate the second electrolyte, and also increases the stress-bearing area of ​​the electrolyte replenishment assembly, causing it to break slowly, thereby reducing the impact on the battery cells when the electrolyte replenishment assembly breaks.

[0030] Secondly, embodiments of this application provide a battery comprising the battery cell described in any of the above embodiments. Since the battery provided in this application includes the battery cell described in the above embodiments, it possesses the technical effects of the battery cell described in the above embodiments, which will not be repeated here.

[0031] Thirdly, embodiments of this application provide an electrical device including the battery described in the above embodiments. Because the electrical device provided in this application includes the battery described in the above embodiments, it has higher safety performance and a longer service life.

[0032] 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, specific embodiments of this application are given below. Attached Figure Description

[0033] Various other advantages and benefits will become apparent to those skilled in the art upon reading the detailed description of the preferred embodiments below. The accompanying drawings are for illustrative purposes only and are not intended to limit the scope of this application. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings:

[0034] Figure 1 This application provides structural schematic diagrams of vehicles for some embodiments;

[0035] Figure 2 Exploded views of batteries provided in some embodiments of this application are shown;

[0036] Figure 3 The present application provides schematic diagrams of the structure of a single battery cell according to some embodiments.

[0037] Figure 4 Exploded views of a battery cell provided in some embodiments of this application are shown;

[0038] Figure 5 A cross-sectional structural schematic diagram of a battery cell provided in some embodiments of this application is shown;

[0039] Figure 6 A cross-sectional structural schematic diagram of a battery cell provided in some embodiments of this application is shown;

[0040] Figure 7 A cross-sectional structural schematic diagram of a battery cell provided in some other embodiments of this application is shown;

[0041] Figure 8The diagram shows the aging time T and the thickness D1 of the cavity wall of the first liquid storage cavity in a battery cell provided in some embodiments of this application.

[0042] Figure 9 The diagram shows the variation of the maximum stress P and the wall thickness D2 of the second liquid storage chamber in the battery cell provided in other embodiments of this application.

[0043] Figure 10 Cyclic performance diagrams of the battery cells provided in Embodiment 1 and Comparative Example 1 of this application are shown;

[0044] Figure 11 Cyclic performance diagrams of the battery cells provided in Embodiment 2 and Comparative Example 2 of this application are shown;

[0045] Figure 12 The graphs showing the stress generated inside the battery cell provided in Example 3 and Comparative Example 3 versus the number of cycles are shown.

[0046] Figure 13 The graphs showing the stress generated inside the battery cell provided in Example 4 and Comparative Example 4 versus the number of cycles are shown.

[0047] The reference numerals in the detailed embodiments are as follows:

[0048] 1000 - Vehicles;

[0049] 100 - Battery, 200 - Controller, 300 - Motor;

[0050] 10-Box body, 11-First part, 12-Second part;

[0051] 20-cell battery;

[0052] 21-Shell;

[0053] 22-Electrode assembly, 221-Positive electrode tab, 222-Negative electrode tab;

[0054] 23-End cap, 231-Positive electrode terminal, 232-Negative electrode terminal;

[0055] 24-Replenishment Components. Detailed Implementation

[0056] The embodiments of the technical solution of this application will now be described in detail with reference to the accompanying drawings. These embodiments are only used to more clearly illustrate the technical solution of this application and are therefore merely examples, and should not be used to limit the scope of protection of this application.

[0057] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms “comprising” and “having”, and any variations thereof, in the specification, claims, and foregoing description of the drawings are intended to cover non-exclusive inclusion.

[0058] In the description of the embodiments of this application, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly defined.

[0059] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0060] In the description of the embodiments in this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.

[0061] In the description of the embodiments of this application, the term "multiple" refers to two or more (including two), similarly, "multiple sets" refers to two or more (including two sets), and "multiple pieces" refers to two or more (including two pieces).

[0062] In the description of the embodiments of this application, the technical terms "center", "longitudinal", "lateral", "length", "width", "wall thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of this application and simplifying the description, and 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. Therefore, they should not be construed as limitations on the embodiments of this application.

[0063] In the description of the embodiments of this application, unless otherwise expressly specified and limited, the technical terms such as "installation," "connection," "joining," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. For those skilled in the art, the specific meaning of the above terms in the embodiments of this application can be understood according to the specific circumstances.

[0064] In this application, a battery refers to a single physical module comprising one or more battery cells to provide higher voltage and capacity. For example, the battery mentioned in this application may include a battery module or a battery pack. A battery generally includes a housing for encapsulating one or more battery cells. The housing prevents liquids or other foreign matter from affecting the charging or discharging of the battery cells.

[0065] Battery cells may include lithium-ion rechargeable battery cells, lithium-ion primary battery cells, lithium-sulfur battery cells, sodium-ion battery cells, or magnesium-ion battery cells, etc., and this application embodiment is not limited to these. Battery cells may be cylindrical, flat, cuboid, or other shapes, etc., and this application embodiment is not limited to these. Battery cells are generally classified into three types according to their packaging method: cylindrical battery cells, square battery cells, and pouch battery cells, and this application embodiment is not limited to these.

[0066] A battery cell includes an electrode assembly and an electrolyte. The electrode assembly consists of a positive electrode, a negative electrode, and a separator. The battery cell primarily functions by the movement of metal ions between the positive and negative electrodes. 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 the uncoated positive current collector protrudes beyond the coated positive current collector, serving as the positive electrode tab.

[0067] In addition, the battery cell also includes a housing for housing the electrode assembly and electrolyte, wherein the electrolyte can play a role in transferring electrons between the positive and negative electrode plates.

[0068] During battery cell use, the electrolyte is gradually consumed as the number of cycles increases. When the electrolyte is consumed to a certain extent, the amount of electrolyte remaining in the casing is insufficient to completely wet the negative electrode. This leads to lithium plating on the unwetted negative electrode. The deposited lithium ions pose a significant safety hazard and can also undergo side reactions with the electrolyte, affecting the battery's cycle performance.

[0069] Therefore, embodiments of this application provide a battery cell, a battery, and an electrical device that can improve the safety and cycle performance of the battery cell.

[0070] The battery cells and batteries disclosed in this application can be assembled into a power system for an electrical device, which can help improve the safety performance and service life of the electrical device.

[0071] In this application, 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.

[0072] For ease of explanation, the following embodiments will use a vehicle as an example of an electrical device according to an embodiment of this application.

[0073] Electrical appliances

[0074] Figure 1 The diagram shows a structural schematic of a vehicle provided in some embodiments of this application.

[0075] Please refer to Figure 1 The vehicle 1000 has a battery 100 installed inside, which can be located at the bottom, front, or rear of the vehicle 1000. The battery 100 can be used to power the vehicle 1000; for example, it can serve as the vehicle 1000's operating power source. The vehicle 1000 may also include a controller 200 and a motor 300. The controller 200 controls the battery 100 to supply power to the motor 300, for example, to meet the power needs of the vehicle 1000 during startup, navigation, and driving.

[0076] In some embodiments of this application, the battery 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.

[0077] Battery

[0078] Figure 2 A schematic diagram of the structure of a battery provided in some embodiments of this application is shown.

[0079] Please refer to Figure 2 The battery 100 includes a housing 10 and a battery cell 20, with the housing 10 used to house the battery cell 20.

[0080] The housing 10 is a component that houses the battery cell 20, providing a space for the battery cell 20. The housing 10 can adopt various structures. In some embodiments, the housing 10 may include a first part 11 and a second part 12, which overlap each other to define a space for accommodating the battery cell 20. The first part 11 and the second part 12 can have various shapes, such as a cuboid or a cylinder. The first part 11 can be a hollow structure open on one side, and the second part 12 can also be a hollow structure open on one side, with the open side of the second part 12 overlapping the open side of the first part 11, thus forming a housing 10 with a accommodating space. Alternatively, the first part 11 can be a hollow structure open on one side, and the second part 12 can be a plate-like structure, with the second part 12 overlapping the open side of the first part 11, thus forming a housing 10 with a accommodating space. The first part 11 and the second part 12 can be sealed using a sealing element, such as a sealing ring or sealant.

[0081] In battery 100, there can be one or more battery cells 20. If there are multiple battery cells 20, they 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. Alternatively, multiple battery cells 20 can be first connected in series, parallel, or in a mixed manner to form a battery module, and then multiple battery modules can be connected in series, parallel, or in a mixed manner to form a whole, which is then housed within the housing 10. Another option is that all battery cells 20 can be directly connected in series, parallel, or in a mixed manner, and then the whole consisting of all battery cells 20 is housed within the housing 10.

[0082] battery cell

[0083] Figure 3 A schematic diagram of the structure of a battery cell provided in some embodiments of this application is shown. Figure 4 Exploded views of battery cells provided in some embodiments of this application are shown.

[0084] Please refer to Figure 3 and 4 The battery cell 20 includes a housing 21, an electrode assembly 22, a first electrolyte, and a replenishment assembly 24. The housing 21 has a receiving cavity. The electrode assembly 22 is disposed within the receiving cavity. The first electrolyte is contained within the receiving cavity and is used to wet the electrode assembly 22. The replenishment assembly 24 is used to store a second electrolyte to release the second electrolyte into the first electrolyte in response to predetermined conditions.

[0085] In the battery cell 20 provided in this application embodiment, as the number of cycles increases, the first electrolyte is gradually consumed. When a predetermined condition is triggered, the electrolyte replenishment component 24 can respond to the predetermined condition and release the stored second electrolyte into the first electrolyte to replenish the electrolyte required for normal charging and discharging of the battery cell 20. This effectively alleviates the lithium plating phenomenon caused by the reduction of electrolyte volume. In this way, the safety performance of the battery cell 20 can be improved, and the cycle performance of the battery cell 20 can also be improved.

[0086] case

[0087] The housing 21 is a component used to house the electrode assembly 22 and the electrolyte. The housing 21 has a hollow structure with an opening at one end, i.e., a receiving cavity. The housing 21 can be of various shapes, such as a cylinder, a cuboid, etc., and this embodiment does not impose any particular limitation on it. The housing 21 can be made of various materials, such as copper, iron, aluminum, steel, aluminum alloy, etc., and this embodiment does not impose any particular limitation on it.

[0088] In some embodiments of this application, the housing 21 includes a bottom wall, two first side walls, and two second side walls. The two first side walls are disposed opposite to each other on the bottom wall along a first direction, and the liquid replenishment assembly 24 is located between the first side walls and the electrode assembly 22. The two second side walls are disposed opposite to each other on the bottom wall along a second direction, and the second side walls connect between the two first side walls to form a receiving cavity, and the area of ​​the second side walls is smaller than the area of ​​the first side walls. The first direction is perpendicular to the second direction.

[0089] In the above embodiments, the electrolyte replenishment component 24 is located between the first sidewall and the electrode component 22, and the area of ​​the first sidewall is larger than the area of ​​the second sidewall. This allows the electrolyte replenishment component 24 to be designed with a larger volume to accommodate the second electrolyte, and also increases the stress-bearing area of ​​the electrolyte replenishment component 24 so that it breaks slowly, thereby reducing the impact on the battery cell 21 when the electrolyte replenishment component 24 breaks.

[0090] You can continue to refer to Figure 4In some embodiments of this application, the battery cell 20 may further include an end cap 23, which is a component that closes onto the opening of the housing 21 to isolate the internal environment of the battery cell 20 from the external environment. The end cap 23 closes onto the opening of the housing 21, and the end cap 23 and the housing 21 together define a sealed space for accommodating the electrode assembly 22, electrolyte, and other components. The shape of the end cap 23 may be adapted to the shape of the housing 21. For example, if the housing 21 is a cuboid structure, the end cap 23 may be a rectangular plate structure adapted to the housing 21; or, if the housing 21 is a cylindrical structure, the end cap 23 may be a circular plate structure adapted to the housing 21. The material of the end cap 23 may also be various, such as copper, iron, aluminum, steel, aluminum alloy, etc. The material of the end cap 23 may be the same as or different from the material of the housing 21.

[0091] Electrode terminals can be provided on the end cap 23. These terminals are used for electrical connection with the electrode assembly 22 to output electrical energy from the battery cell 20. The electrode terminals may include a positive electrode terminal 231 and a negative electrode terminal 232. The electrode assembly 22 has a positive electrode tab 221 and a negative electrode tab 222. The positive electrode terminal 231 is used for electrical connection with the positive electrode tab 221, and the negative electrode terminal 232 is used for electrical connection with the negative electrode tab 222. The positive electrode terminal 231 and the positive electrode tab 221 can be directly connected or indirectly connected, as can the negative electrode terminal 232 and the negative electrode tab 222.

[0092] Electrode assembly

[0093] Continue to refer to Figure 4 The electrode assembly 22 inside the housing 21 can be one or more. For example, such as Figure 4 As shown, there are multiple electrode assemblies 22, which are stacked in layers.

[0094] Electrode assembly 22 is a component in battery cell 20 where electrochemical reactions occur. It can be formed by a wound structure or by a stacked structure. This application does not make any particular limitation on this.

[0095] In some embodiments of this application, the electrode assembly 22 includes a positive electrode, a negative electrode, and a separator. The positive electrode includes a positive current collector and a positive active material layer disposed on at least one surface of the positive current collector, the positive active material layer comprising a positive active material. The negative electrode includes a negative current collector and a negative active material layer disposed on at least one surface of the negative current collector, the negative active material layer comprising a negative active material. The separator is disposed between the positive and negative electrode. The positive active material is selected from at least one of lithium cobalt oxide, lithium iron phosphate, lithium manganese oxide, lithium-rich, and ternary positive active materials. The negative active material is selected from at least one of carbon-containing, silicon-containing, alloy, lithium-containing, and tin-containing negative active materials.

[0096] The positive electrode current collector can be made of materials such as metal foil or porous metal plate. For example, the material of the positive electrode current collector can be, but is not limited to, foil or porous plate of metals such as copper, nickel, titanium, or silver, or their alloys. Furthermore, in some specific embodiments of this application, the positive electrode current collector is made of aluminum foil.

[0097] The negative electrode current collector can be made of materials such as metal foil or porous metal plate. For example, the material of the negative electrode current collector can be, but is not limited to, foil or porous plate of metals or alloys thereof, such as copper, nickel, titanium, or iron. Furthermore, in some specific embodiments of this application, the negative electrode current collector is made of copper foil.

[0098] In some embodiments of this application, the positive electrode active material layer may further include a conductive agent and a binder. This application does not impose any particular limitation on the types of conductive agents and binders in the positive electrode active material layer; they can be selected according to actual needs.

[0099] For example, the conductive agent may be, but is not limited to, one or more of graphite, superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers; the binder may be, but is not limited to, styrene-butadiene rubber (SBR), waterborne acrylic resin, carboxymethyl cellulose (CMC), polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), polyvinyl butyral (PVB), ethylene-vinyl acetate copolymer (EVA), vinylidene fluoride-tetrafluoroethylene-propylene terpolymer, vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene terpolymer, tetrafluoroethylene-hexafluoropropylene copolymer, fluorinated acrylic resin, and polyvinyl alcohol (PVA).

[0100] In the embodiments of this application, the positive electrode active material, conductive agent, and binder are thoroughly mixed in an appropriate amount of N-methylpyrrolidone (NMP) at a certain mass ratio to form a uniform positive electrode slurry; the positive electrode slurry is coated on the surface of the positive electrode current collector aluminum foil, and after drying and cold pressing, a positive electrode sheet is obtained.

[0101] In some embodiments of this application, the negative electrode active material layer may further include a conductive agent and a binder. This application does not impose any particular limitation on the types of conductive agents and binders in the negative electrode active material layer; they can be selected according to actual needs.

[0102] For example, the conductive agent may be, but is not limited to, one or more of graphite, superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers; the binder may be, but is not limited to, one or more of styrene-butadiene rubber (SBR), polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), polyvinyl butyral (PVB), waterborne acrylic resin, and carboxymethyl cellulose (CMC).

[0103] In the embodiments of this application, the negative electrode active material, conductive agent, and binder are mixed in a certain mass ratio and stirred thoroughly in an appropriate amount of deionized water to form a uniform negative electrode slurry; the negative electrode slurry is coated on the surface of the negative electrode current collector copper foil, and after drying and cold pressing, a negative electrode sheet is obtained.

[0104] This application does not impose any particular limitation on the type of separator membrane; any known porous separator membrane with good chemical and mechanical stability can be selected. In some embodiments, the material of the separator membrane can be selected from one or more of glass fiber, nonwoven fabric, polyethylene, polypropylene, and polyvinylidene fluoride. The separator membrane can be a single-layer film or a multi-layer composite film. When the separator membrane is a multi-layer composite film, the materials of each layer can be the same or different.

[0105] First electrolyte

[0106] In embodiments of this application, the first electrolyte may include an organic solvent and an electrolyte salt. In some embodiments of this application, the organic solvent may include at least one selected from dimethyl carbonate, diethyl carbonate, propylene carbonate, methyl ethyl carbonate, ethyl formate, ethyl acetate, ethylene carbonate, tetrahydrofuran, 2-methylfuran, 3-methylfuran, 2-ethylfuran, 2-propylfuran, 2-butylfuran, 2,3-dimethylfuran, 2,4-dimethylfuran, 2,5-dimethylfuran, pyran, 2-methylpyran, 3-methylpyran, 4-methylpyran, benzofuran, and 2-(2-nitrovinyl)furan.

[0107] In some embodiments of this application, the electrolyte salt can be a lithium salt, for example, LiCl, LiBr, LiI, LiClO4, LiBF4, or LiB. 10 Cl 10 , LiPF6, LiFSI, LiCF3SO3, LiCF3CO2, LiC4BO8, LiAsF6, LiSbF6, LiAlCl4, CH3SO3Li, CF3SO3Li, (CF3SO2)2NLi, (C2F5SO2)2NLi, (SO2F)2NLi, (CF3SO2)3CLi.

[0108] fluid replenishment kit

[0109] In embodiments of this application, the replenishment component 24 is used to store the second electrolyte and can release the second electrolyte into the first electrolyte in response to predetermined conditions.

[0110] Figure 5 A cross-sectional structural schematic diagram of a battery cell provided in some embodiments of this application is shown. Figure 6 A cross-sectional structural schematic diagram of a battery cell provided in some embodiments of this application is shown.

[0111] In some embodiments of this application, the replenishment component 24 includes a first replenishment element 241, which has a sealed first reservoir for storing a second electrolyte. The wall of the first reservoir is capable of rupturing under predetermined conditions to release the second electrolyte into the first electrolyte. The predetermined conditions include an aging time T of the wall of the first reservoir.

[0112] In this application, aging time refers to the time it takes for the wall of the first liquid storage chamber to age and crack due to a series of changes in its structure and / or composition under the influence of external or environmental factors, resulting in the opening of the sealed first liquid storage chamber and its connection with the outside world.

[0113] Please refer to Figure 6 The first liquid storage chamber may include multiple chambers for storing the second electrolyte. These chambers may be interconnected, partially interconnected, or independent of each other. The design of the chambers within the first liquid storage chamber can be tailored to specific circumstances, and this application does not impose any particular limitations on this design.

[0114] In addition, the number of first fluid replenishment components 241 can be one or more, and the specific number can be adjusted according to actual application requirements.

[0115] In the above embodiments, the first electrolyte replenishment member 241 has a sealed first electrolyte storage chamber for storing the second electrolyte. The wall of the first electrolyte storage chamber automatically ruptures at a suitable aging time T to release the second electrolyte into the first electrolyte. This allows for the timely replenishment of electrolyte, which can improve the safety performance of the battery cell 20 and also help improve the cycle performance of the battery cell 20.

[0116] In embodiments of this application, the shape of the first liquid replenishing component 241 can be any shape that can be installed into the receiving cavity of the housing 21. In some embodiments, the shape of the first liquid replenishing component 241 is selected from any one of the following shapes: circular, gourd-shaped, elliptical, and square. Selecting the shape of the first liquid replenishing component 241 from any of the above shapes can facilitate the installation of the first liquid replenishing component 241 into the receiving cavity of the housing 21, thereby facilitating the assembly of the battery cell 20.

[0117] Furthermore, the volume of the first liquid storage chamber within the first liquid replenishment component 241 can be designed according to the capacity of the battery cell 20. In some embodiments of this application, the volume V1 of the first liquid storage chamber and the capacity A of the battery cell 20 satisfy the following relationship: 0.05 mL / Ah ≤ V1 / A ≤ 0.2 mL / Ah.

[0118] In the above embodiments, the volume V1 of the first electrolyte storage chamber and the capacity A of the battery cell 20 satisfy the above relationship. This allows the amount of second electrolyte stored in the first electrolyte storage chamber to reasonably fill the amount of first electrolyte consumed in the battery cell 20, thereby further improving the cycle performance of the battery cell 20.

[0119] In some embodiments of this application, the volume V1 of the first electrolyte storage chamber is in the range of 2.5 mL to 60 mL. With the volume V1 set within this suitable range, the first electrolyte storage chamber can store an appropriate amount of the second electrolyte. Under a suitable aging time T, the first replenishing element 241 can release an appropriate amount of the second electrolyte into the first electrolyte, thereby further improving the safety and cycle performance of the battery cell 20.

[0120] For example, the volume V1 of the first liquid storage chamber can be, but is not limited to, 2.5 mL, 3 mL, 3.5 mL, 4 mL, 4.5 mL, 5 mL, 5.5 mL, 6 mL, 6.5 mL, 7 mL, 8 mL, 9 mL, 10 mL, 11 mL, 12 mL, 13 mL, 14 mL, 15 mL, 16 mL, 17 mL, 18 mL, 19 mL, 20 mL, 21 mL, 22 mL, 23 mL, 24 mL, 25 mL, 26 mL, 27 mL, etc. mL, 28mL, 29mL, 30mL, 31mL, 32mL, 33mL, 34mL, 35mL, 36mL, 37mL, 38mL, 39mL, 40mL, 41mL, 42mL, 43mL, 4 4mL, 45mL, 46mL, 47mL, 48mL, 49mL, 50mL, 51mL, 52mL, 53mL, 54mL, 55mL, 56mL, 57mL, 58mL, 59mL, 60mL.

[0121] The volume V1 of the first liquid storage chamber and the capacity A of the battery cell 20 satisfy the following relationship: 0.05mL / Ah≤V1 / A≤0.2mL / Ah. In some embodiments of this application, the capacity A of the battery cell 20 can be 50Ah-300Ah, which enables the battery cell 20 to meet the basic requirements of practical applications.

[0122] For example, the capacity A of the battery cell 20 can be, but is not limited to, 50Ah, 55Ah, 60Ah, 65Ah, 70Ah, 75Ah, 80Ah, 85Ah, 90Ah, 95Ah, 100Ah, 105Ah, 110Ah, 115Ah, 120Ah, 125Ah, 130Ah, 135Ah, 140Ah, 145Ah, 150Ah, 155Ah, 160Ah, 165Ah, 170Ah, etc. Ah, 175Ah, 180Ah, 185Ah, 190Ah, 195Ah, 200Ah, 205Ah, 210Ah, 215Ah, 220Ah, 225Ah, 230Ah, 235A h, 240Ah, 245Ah, 250Ah, 255Ah, 260Ah, 265Ah, 270Ah, 275Ah, 280Ah, 285Ah, 290Ah, 295Ah, 300Ah.

[0123] In the embodiments of this application, the structure and / or composition of the cavity wall material of the first liquid storage chamber can age under external or environmental factors, so as to open the sealed first liquid storage chamber and release the stored second electrolyte into the first electrolyte.

[0124] In some embodiments of this application, the wall material of the first electrolyte reservoir may include at least one of polyethylene terephthalate, polycarbonate, polyvinyl chloride, polyvinylidene fluoride, polyethylene, and polyvinylidene chloride. The aforementioned materials comprising the wall material of the first electrolyte reservoir enable the first electrolyte reservoir to automatically rupture at a suitable aging time T, releasing the second electrolyte. Furthermore, the aforementioned materials also enable the first electrolyte replenishment member 241 to possess a certain degree of elasticity, thereby reducing the risk of damage to the battery cell 20 during movement.

[0125] Figure 7 The diagram shows the aging time T and the thickness D1 of the cavity wall of the first liquid storage cavity in the battery cell 20 provided in some embodiments of this application.

[0126] Please refer to Figure 7 In some embodiments of this application, the aging time T of the cavity wall of the first liquid storage chamber and the thickness D1 of the cavity wall of the first liquid storage chamber satisfy the following relationship: T = -0.0005D1 2 +0.1648D1-2.0971, where the aging time T of the first liquid storage chamber wall is in years, and the thickness D1 of the first liquid storage chamber wall is in μm.

[0127] In this embodiment, the cavity wall of the first liquid storage chamber includes an inner cavity wall and an outer cavity wall. The inner cavity wall can be understood as the cavity wall in contact with the second electrolyte, i.e., the inner surface of the first liquid storage chamber, and the outer cavity wall can be understood as the cavity wall in contact with the outside world, i.e., the outer surface of the first liquid storage chamber. The thickness D1 of the cavity wall of the first liquid storage chamber refers to the distance between the inner surface and the outer surface of the first liquid storage chamber.

[0128] In the above embodiments, the aging time T of the first liquid storage chamber wall and the thickness D1 of the first liquid storage chamber wall satisfy the above relationship. Thus, the aging time T of the first liquid storage chamber wall can be controlled by the thickness D1 of the first liquid storage chamber wall, making it adaptable to different types of battery cells 20. The wall of the first liquid storage chamber automatically ruptures at a suitable aging time T, releasing the second electrolyte into the first electrolyte, thereby improving the safety and cycle performance of the battery cell 20.

[0129] In some embodiments of this application, the aging time T of the cavity wall of the first liquid storage chamber is in the range of 1 to 10 years. Setting the aging time T of the cavity wall of the first liquid storage chamber within the above range can help the first liquid replenishment component 241 to replenish electrolyte to the battery cell 20 in a timely manner, thereby improving the cycle performance of the battery cell 20.

[0130] In some embodiments of this application, the aging time T of the wall of the first liquid storage chamber is in the range of 5 to 8 years.

[0131] For example, the aging time T of the cavity wall of the first liquid storage cavity can be 1 year, 2 years, 3 years, 4 years, 5 years, 6 years, 7 years, 8 years, 9 years, or 10 years.

[0132] In some embodiments of this application, the thickness D1 of the wall of the first liquid storage chamber is in the range of 20μm-100μm. Setting the thickness D1 of the wall of the first liquid storage chamber within the above-mentioned suitable range can help the first liquid replenishment element 241 to automatically break at the corresponding aging time T and release the second electrolyte into the first electrolyte in a timely manner.

[0133] In some embodiments of this application, the thickness D1 of the wall of the first liquid storage chamber is in the range of 50 μm to 100 μm. Setting the thickness D1 of the wall of the first liquid storage chamber within the above-mentioned suitable range can further help the first liquid replenishment element 241 to automatically break at the corresponding aging time T and quickly release the second electrolyte into the first electrolyte.

[0134] For example, the thickness D1 of the cavity wall of the first liquid storage chamber may be, but is not limited to, 20μm, 21μm, 22μm, 23μm, 24μm, 25μm, 26μm, 27μm, 28μm, 29μm, 30μm, 31μm, 32μm, 33μm, 34μm, 35μm, 36μm, 37μm, 38μm, 39μm, 40μm, 41μm, 42μm, 43μm, 44μm, 45μm, 46μm, 47μm, 48μm, 49μm, 50μm, 51μm, 52μm, 53μm, 54μm, 55μm, 56μm, 57μm. 58μm, 59μm, 60μm, 61μm, 62μm, 63μm, 64μm, 65μm, 66μm, 67μm, 68μm, 69μm, 70μm, 71μm, 72μm, 73μm, 74μm, 75μm, 76μm, 77μm, 78μm, 79μm m, 80μm, 81μm, 82μm, 83μm, 84μm, 85μm, 86μm, 87μm, 88μm, 89μm, 90μm, 91μm, 92μm, 93μm, 94μm, 95μm, 96μm, 97μm, 98μm, 99μm, 100μm.

[0135] During the use of the battery cell 20, as the number of cycles increases, the first electrolyte is gradually consumed and may also undergo side reactions with other components to generate gas, causing the battery cell 20 to expand. Therefore, in some embodiments of this application, the second electrolyte stored in the first reservoir includes at least one of vinylene carbonate, fluoroethylene carbonate, carboxylic acid ester, sulfate ester, and sulcolone. The additives contained in the second electrolyte can reduce the occurrence of side reactions and reduce gas generation, thereby reducing the expansion of the battery cell 20.

[0136] It should be noted that the additives included in the second electrolyte can also be selected according to the model of the battery cell 20 and the cycle status of the battery cell 20.

[0137] Figure 8 A cross-sectional structural schematic diagram of a battery cell provided in some embodiments of this application is shown.

[0138] Please refer to Figure 8 In some embodiments of this application, the replenishment component 24 includes a second replenishment element 242, which has a sealed second reservoir for storing a second electrolyte. The wall of the second reservoir is capable of rupturing under predetermined conditions to release the second electrolyte into the first electrolyte. The predetermined conditions include the maximum stress P borne by the wall of the second reservoir.

[0139] The second liquid storage chamber may include multiple chambers for storing the second electrolyte. These chambers may be interconnected, partially interconnected, or independent of each other. The design of the chambers within the second liquid storage chamber can be tailored to specific circumstances, and this application does not impose any particular limitations on this design.

[0140] The maximum stress P refers to the stress limit value at a specific location on the cavity wall after a load is applied to the cavity wall and the load is removed.

[0141] In addition, the number of second fluid replenishment components 242 can be one or more, and the specific number can be adjusted according to actual application requirements.

[0142] In the above embodiments, the second electrolyte replenishment member 242 has a sealed second electrolyte storage chamber for storing the second electrolyte. The wall of the second electrolyte storage chamber automatically ruptures under a suitable maximum stress P to release the second electrolyte into the first electrolyte. This allows for the timely replenishment of electrolyte, which can improve the safety performance of the battery cell 20 and also help improve the cycle performance of the battery cell 20.

[0143] In some embodiments of this application, the shape of the second liquid replenishing component 242 is selected from any one of the following shapes: circular, gourd-shaped, elliptical, and square. The selection of any of these shapes for the second liquid replenishing component 242 facilitates the installation of the first liquid replenishing component 241 into the receiving cavity of the housing 21, thereby simplifying the assembly of the battery cell 20.

[0144] In some embodiments of this application, the volume V2 of the second liquid storage chamber and the capacity A of the battery cell 20 satisfy the following relationship: 0.05mL / Ah≤V2 / A≤0.2mL / Ah.

[0145] In the above embodiments, the volume V2 of the second electrolyte storage chamber and the capacity A of the battery cell 20 satisfy the above relationship. This allows the amount of second electrolyte stored in the second electrolyte storage chamber to reasonably fill the amount of first electrolyte consumed in the battery cell 20, thereby further improving the cycle performance of the battery cell 20.

[0146] In some embodiments of this application, the volume V2 of the second electrolyte storage chamber is in the range of 2.5 mL to 60 mL. Setting the volume V2 of the second electrolyte storage chamber within this suitable range allows it to store an appropriate amount of the second electrolyte and automatically rupture under maximum stress P to release an appropriate amount of the second electrolyte into the first electrolyte, thereby further improving the safety and cycle performance of the battery cell 20.

[0147] For example, the volume V2 of the second reservoir can be, but is not limited to, 2.5 mL, 3 mL, 3.5 mL, 4 mL, 4.5 mL, 5 mL, 5.5 mL, 6 mL, 6.5 mL, 7 mL, 8 mL, 9 mL, 10 mL, 11 mL, 12 mL, 13 mL, 14 mL, 15 mL, 16 mL, 17 mL, 18 mL, 19 mL, 20 mL, 21 mL, 22 mL, 23 mL, 24 mL, 25 mL, 26 mL, 27 mL, etc. mL, 28mL, 29mL, 30mL, 31mL, 32mL, 33mL, 34mL, 35mL, 36mL, 37mL, 38mL, 39mL, 40mL, 41mL, 42mL, 43mL, 4 4mL, 45mL, 46mL, 47mL, 48mL, 49mL, 50mL, 51mL, 52mL, 53mL, 54mL, 55mL, 56mL, 57mL, 58mL, 59mL, 60mL.

[0148] The volume V2 of the second liquid storage chamber and the capacity A of the battery cell 20 satisfy the following relationship: 0.05mL / Ah≤V2 / A≤0.2mL / Ah. In some embodiments of this application, the capacity A of the battery cell 20 can be 50Ah-300Ah, which enables the battery cell 20 to meet the basic requirements of practical applications.

[0149] For example, the capacity A of the battery cell 20 can be, but is not limited to, 50Ah, 55Ah, 60Ah, 65Ah, 70Ah, 75Ah, 80Ah, 85Ah, 90Ah, 95Ah, 100Ah, 105Ah, 110Ah, 115Ah, 120Ah, 125Ah, 130Ah, 135Ah, 140Ah, 145Ah, 150Ah, 155Ah, 160Ah, 165Ah, 170Ah, etc. Ah, 175Ah, 180Ah, 185Ah, 190Ah, 195Ah, 200Ah, 205Ah, 210Ah, 215Ah, 220Ah, 225Ah, 230Ah, 235A h, 240Ah, 245Ah, 250Ah, 255Ah, 260Ah, 265Ah, 270Ah, 275Ah, 280Ah, 285Ah, 290Ah, 295Ah, 300Ah.

[0150] Figure 9 The diagram shows the variation of the maximum stress P and the wall thickness D2 of the second liquid storage chamber in the battery cell 20 provided in other embodiments of this application.

[0151] In some embodiments of this application, the maximum stress P borne by the wall of the second liquid storage chamber and the thickness D2 of the wall of the second liquid storage chamber satisfy the following relationship: P = 0.0945D2 2 +3.7533D2+184.51, where the maximum stress P borne by the wall of the second liquid storage chamber is in kgf, and the thickness D2 of the wall of the second liquid storage chamber is in μm.

[0152] In the above embodiments, the maximum stress P borne by the wall of the second liquid storage chamber and the thickness D2 of the wall of the second liquid storage chamber satisfy the above relationship. In this way, the maximum stress P borne by the wall of the second liquid storage chamber can be controlled by the thickness D2 of the wall of the second liquid storage chamber, so that it can adapt to different models of battery cells 20, automatically break under the appropriate maximum stress P, and release the second electrolyte into the first electrolyte, thereby improving the safety performance and cycle performance of the battery cell 20.

[0153] In some embodiments of this application, the maximum stress P borne by the wall of the second electrolyte reservoir is in the range of 200 kgf to 1500 kgf. Setting the maximum stress P within this suitable range allows the second electrolyte replenishment element 242 to rupture at different stages of the battery cell 20, releasing the second electrolyte into the first electrolyte, thereby meeting the electrolyte requirements of the battery cell 20 at different stages and improving the safety and cycle performance of the battery cell 20.

[0154] In some embodiments of this application, the maximum stress P borne by the wall of the second liquid storage chamber is in the range of 500 kgf to 1100 kgf. Setting the maximum stress P borne by the wall of the second liquid storage chamber within the above-mentioned suitable range can further improve the safety performance and cycle performance of the battery cell 20.

[0155] For example, the maximum stress P borne by the wall of the second liquid storage chamber may be, but is not limited to, 200 kgf, 250 kgf, 300 kgf, 350 kgf, 400 kgf, 450 kgf, 500 kgf, 550 kgf, 600 kgf, 650 kgf, 700 kgf, 750 kgf, 800 kgf, 850 kgf, 900 kgf, 950 kgf, 1000 kgf, 1050 kgf, 1100 kgf, 1150 kgf, 1200 kgf, 1250 kgf, 1300 kgf, 1350 kgf, 1400 kgf, 1450 kgf, or 1500 kgf.

[0156] In some embodiments of this application, the thickness D2 of the wall of the second liquid storage chamber is in the range of 20 μm to 100 μm. Setting the thickness D2 of the wall of the second liquid storage chamber within the above-mentioned suitable range allows the second liquid storage chamber to withstand different maximum stresses P and causes the second liquid replenishment member 242 to rupture at different stages, thereby releasing the second electrolyte into the first electrolyte.

[0157] In some embodiments of this application, the thickness D2 of the wall of the second liquid storage chamber is in the range of 50μm-100μm.

[0158] For example, the thickness D2 of the cavity wall of the second liquid storage chamber may, but is not limited to, 20μm, 21μm, 22μm, 23μm, 24μm, 25μm, 26μm, 27μm, 28μm, 29μm, 30μm, 31μm, 32μm, 33μm, 34μm, 35μm, 36μm, 37μm, 38μm, 39μm, 40μm, 41μm, 42μm, 43μm, 44μm, 45μm, 46μm, 47μm, 48μm, 49μm, 50μm, 51μm, 52μm, 53μm, 54μm, 55μm, 56μm, 57μm. 58μm, 59μm, 60μm, 61μm, 62μm, 63μm, 64μm, 65μm, 66μm, 67μm, 68μm, 69μm, 70μm, 71μm, 72μm, 73μm, 74μm, 75μm, 76μm, 77μm, 78μm, 79μm m, 80μm, 81μm, 82μm, 83μm, 84μm, 85μm, 86μm, 87μm, 88μm, 89μm, 90μm, 91μm, 92μm, 93μm, 94μm, 95μm, 96μm, 97μm, 98μm, 99μm, 100μm.

[0159] In some embodiments of this application, the second electrolyte stored in the second reservoir includes at least one selected from vinylene carbonate, fluoroethylene carbonate, carboxylic acid ester, sulfate ester, and sulcolone. The aforementioned materials comprising the wall material of the second reservoir enable it to automatically rupture under varying maximum stresses P, releasing the second electrolyte. Furthermore, these materials also impart a degree of elasticity to the second electrolyte, reducing the risk of damage to the battery cell 20 during operation.

[0160] In some embodiments of this application, the replenishment component 24 is located between the inner wall of the housing 21 and the electrode assembly 22. The replenishment component 24 is positioned between the housing 21, the inner wall, and the electrode assembly 22, which allows the replenishment component 24 to quickly release the second electrolyte into the first electrolyte upon responding to predetermined conditions, and also reduces external damage to the replenishment component 24.

[0161] In addition, the liquid replenishment assembly 24 can be fixedly connected to the inner wall of the housing 21 and / or the outer surface of the electrode assembly 22, which can reduce the damage to the liquid replenishment assembly 24 caused by shaking of the battery cell 20 during transportation or use.

[0162] Example

[0163] The following embodiments describe the disclosure of this application in more detail. These embodiments are merely illustrative, as various modifications and variations will be apparent to those skilled in the art within the scope of the disclosure of this application. Unless otherwise stated, all parts, percentages, and ratios reported in the following embodiments are based on weight, and all reagents used in the embodiments are commercially available or synthesized by conventional methods and can be used directly without further processing, and the instruments used in the embodiments are commercially available.

[0164] Example 1

[0165] Preparation of positive electrode sheet

[0166] LiNi, the positive electrode active material 0.5 Co 0.2 Mn 0.3 O2, conductive agent Super P, and binder polyvinylidene fluoride (PVDF) are mixed thoroughly in NMP at a mass ratio of 96.6:2.3:1.1 to form a uniform positive electrode slurry. The positive electrode slurry is coated on the surface of the current collector aluminum foil and dried at 85°C. Then, it is cold-pressed, trimmed, cut into sheets, and slit. Finally, it is dried under vacuum at 85°C for 4 hours to obtain the positive electrode sheet.

[0167] Preparation of negative electrode sheet

[0168] The negative electrode active material graphite, conductive agent Super P, thickener CMC, and binder styrene-butadiene rubber (SBR) were thoroughly stirred in deionized water at a mass ratio of 97:0.7:1.0:1.3 to form a uniform negative electrode slurry, wherein the solid content of the negative electrode slurry was 30wt%. The negative electrode slurry was coated on the surface of the current collector copper foil and dried at 85℃. Then, it was cold-pressed, trimmed, cut into sheets, and slit. Finally, it was dried under vacuum at 120℃ for 12 hours to obtain the negative electrode sheet.

[0169] Separating membrane

[0170] A polyethylene film (PE) with a wall thickness of 16 μm is used.

[0171] Preparation of the first electrolyte

[0172] In an argon-filled glove box (water content <10ppm, oxygen content <1ppm), organic solvents are mixed in a mass ratio of EC:DEC:DMC = 30:50:20, and then 2% (equivalent to 2% of the organic solvent mass) of vinylene carbonate is added. After mixing evenly, 1 mol / L LiFP6 is slowly added to the above solution. After the LiFP6 is completely dissolved, the first electrolyte is obtained.

[0173] Preparation of the second electrolyte

[0174] In an argon-filled glove box (water content <10ppm, oxygen content <1ppm), organic solvents are mixed in a mass ratio of EC:DEC:DMC = 30:50:20, and then 2% fluoroethylene carbonate (equivalent to 2% of the organic solvent mass) is added. After mixing evenly, 1 mol / L LiFP6 is slowly added to the above solution. After the LiFP6 is completely dissolved, the second electrolyte is obtained.

[0175] Preparation of battery cells

[0176] The positive electrode, separator, and negative electrode are stacked and wound in sequence to obtain an electrode assembly. The electrode assembly is placed in an outer packaging, and the electrolyte prepared above is added. After processes such as encapsulation, standing, formation, and aging, a battery cell is obtained.

[0177] Examples 2-4

[0178] The preparation method is similar to that in Example 1, except that the parameters of the replenishment component are detailed in Table 1.

[0179] Comparative Examples 1-4

[0180] The preparation method is similar to that in Example 1, except that there is no liquid replenishment component.

[0181] Test section

[0182] 1) Testing of the cycle performance of individual battery cells

[0183] At 25℃, a single battery cell was charged at a constant current of 1C to 4.25V, then charged at a constant voltage of 4.25V to a current of 1C, and then discharged at a constant current of 1C to 2.8V. The discharge capacity was recorded as C1. The discharge capacity of the single battery cell after n cycles was recorded as C1. n Then the capacity retention rate (%) of a single battery cell after n cycles = C n / C1×100%, the test results are as follows Figure 10-13 As shown.

[0184] 2) Testing of maximum stress P

[0185] At 25℃, a single battery cell is placed in a three-piece steel clamp. The cell is placed between steel plates 1 and 2, and a pressure sensor is placed between steel plates 2 and 3. Before the initial cycle, a preload of 2000N is applied to the clamp. The sensor is connected to a pressure display. The pressure P (kgf) of the single battery cell after n cycles is equal to the value displayed on the sensor.

[0186] Table 1

[0187]

[0188]

[0189] From Table 1 and Figure 10-13 As can be seen, in the battery cell provided in this application embodiment, as the number of cycles increases, the first electrolyte is gradually consumed. When a predetermined condition is triggered, the electrolyte replenishment component can respond to the predetermined condition and release the stored second electrolyte into the first electrolyte to replenish the electrolyte required for normal charging and discharging of the battery cell. This effectively alleviates the lithium plating phenomenon caused by the reduction of electrolyte volume. In this way, the safety performance of the battery cell can be improved, and the cycle performance of the battery cell can also be improved.

[0190] 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: The shell has a receiving cavity; The electrode assembly is disposed within the receiving cavity; A first electrolyte is contained within the containment cavity and used to wet the electrode assembly; A replenishment assembly for storing a second electrolyte to release the second electrolyte into the first electrolyte in response to predetermined conditions; The replenishment assembly includes a first replenishment element having a sealed first reservoir for storing the second electrolyte. The wall of the first reservoir is capable of rupturing under predetermined conditions to release the second electrolyte into the first electrolyte. The predetermined conditions include an aging time T of the wall of the first reservoir and a wall thickness D1 in the range of 20 μm to 100 μm.

2. The battery cell according to claim 1, characterized in that, The shape of the first fluid replenishment component is selected from any one of the following: circular, gourd-shaped, elliptical, and square.

3. The battery cell according to claim 1, characterized in that, The volume V1 of the first liquid storage chamber and the capacity A of the battery cell satisfy the following relationship: 0.05mL / Ah≤V1 / A≤0.2mL / Ah.

4. The battery cell according to claim 3, characterized in that, The volume V1 of the first liquid storage chamber is in the range of 2.5mL-60mL.

5. The battery cell according to claim 1, characterized in that, The wall material of the first liquid storage chamber includes at least one of polyethylene terephthalate, polycarbonate, polyvinyl chloride, polyvinylidene fluoride, polyethylene, and polyvinylidene chloride.

6. The battery cell according to claim 1, characterized in that, The aging time T of the cavity wall of the first liquid storage cavity and the thickness D1 of the cavity wall of the first liquid storage cavity satisfy the following relationship: T = -0.0005D1 2 + 0.1648D1 - 2.0971 Wherein, the aging time T of the cavity wall of the first liquid storage cavity is in years, and the thickness D1 of the cavity wall of the first liquid storage cavity is in μm.

7. The battery cell according to claim 6, characterized in that, The aging time T of the cavity wall of the first liquid storage cavity is in the range of 1 to 10 years.

8. The battery cell according to claim 6, characterized in that, The aging time T of the cavity wall of the first liquid storage cavity is in the range of 5 to 8 years.

9. The battery cell according to claim 6, characterized in that, The thickness D1 of the cavity wall of the first liquid storage cavity is in the range of 50μm-100μm.

10. The battery cell according to claim 7, characterized in that, The second electrolyte stored in the first storage chamber includes at least one of vinylene carbonate, fluoroethylene carbonate, carboxylic acid ester, sulfate ester, and sulcolone.

11. The battery cell according to claim 1, characterized in that, The replenishment assembly includes a second replenishment element having a sealed second reservoir for storing the second electrolyte. The wall of the second reservoir is capable of rupturing under the predetermined conditions to release the second electrolyte into the first electrolyte. The predetermined conditions include the maximum stress P borne by the wall of the second reservoir.

12. The battery cell according to claim 11, characterized in that, The shape of the second fluid replenishment component is selected from any one of the following: circular, gourd-shaped, oval, and square.

13. The battery cell according to claim 11, characterized in that, The volume V2 of the second liquid storage chamber and the capacity A of the battery cell satisfy the following relationship: 0.05mL / Ah≤V2 / A≤0.2mL / Ah.

14. The battery cell according to claim 13, characterized in that, The volume V2 of the second liquid storage chamber is in the range of 2.5 mL to 60 mL.

15. The battery cell according to claim 11, characterized in that, The maximum stress P borne by the wall of the second liquid storage chamber and the thickness D2 of the wall of the second liquid storage chamber satisfy the following relationship: P=0.0945D2 2 +3.7533D2+184.51 The maximum stress P borne by the wall of the second liquid storage chamber is in kgf, and the thickness D2 of the wall of the second liquid storage chamber is in μm.

16. The battery cell according to claim 15, characterized in that, The maximum stress P borne by the wall of the second liquid storage chamber is in the range of 200 kgf-1500 kgf.

17. The battery cell according to claim 15, characterized in that, The maximum stress P borne by the wall of the second liquid storage chamber is in the range of 500 kgf-1100 kgf.

18. The battery cell according to claim 15, characterized in that, The thickness D2 of the cavity wall of the second liquid storage cavity is in the range of 20μm-100μm.

19. The battery cell according to claim 15, characterized in that, The thickness D2 of the cavity wall of the second liquid storage cavity is in the range of 50μm-100μm.

20. The battery cell according to claim 16, characterized in that, The second electrolyte stored in the second reservoir includes at least one of vinylene carbonate, fluoroethylene carbonate, carboxylic acid ester, sulfate ester, and sulcolone.

21. The battery cell according to claim 1, characterized in that, The fluid replenishment assembly is located between the inner wall of the housing and the electrode assembly.

22. The battery cell according to claim 21, characterized in that, The housing includes: bottom wall; Two first sidewalls are disposed opposite to each other along a first direction on the bottom wall, and the liquid replenishment assembly is located between the first sidewalls and the electrode assembly; Two second sidewalls are disposed opposite to each other along a second direction on the bottom wall. The second sidewalls are connected between the two first sidewalls to form the receiving cavity, and the area of ​​the second sidewall is smaller than the area of ​​the first sidewall. Wherein, the first direction is perpendicular to the second direction.

23. A battery, characterized in that, Includes the battery cell according to any one of claims 1-22.

24. An electrical appliance, characterized in that, Includes the battery described in claim 23.

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