Battery cell, battery device, and electric device

Abstract

The embodiment of the application provides a battery monomer, a battery device and a power utilization equipment, and relates to the technical field of batteries. The battery monomer comprises a shell, an electrode assembly, a protective film, a pressure relief mechanism and an electrolyte detection piece. The shell is provided with a first wall, and the first wall is provided with a pressure relief hole. The electrode assembly is installed in the interior of the shell. The protective film is located on the surface of the first wall away from the electrode assembly and covers the pressure relief hole. The protective film is configured to be at least partially transparent. The pressure relief mechanism is installed in the pressure relief hole. The electrolyte detection piece is installed in the pressure relief hole and located between the protective film and the pressure relief mechanism. The electrolyte detection piece is at least partially arranged to face the transparent part of the protective film and is configured to change color after contacting the electrolyte. The application can accurately find the state of electrolyte leakage caused by damage and failure of the pressure relief mechanism, and improve the accuracy of damage detection of the pressure relief mechanism.

Description

Technical Field

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

[0002] Battery devices are widely used in electronic devices such as mobile phones, laptops, electric vehicles, electric cars, electric airplanes, electric ships, electric toy cars, electric toy ships, electric toy airplanes, and power tools, etc.

[0003] Battery cells are an important component of battery devices. The pressure relief mechanism of a battery cell is prone to failure, leading to electrolyte leakage. Therefore, how to accurately detect electrolyte leakage caused by the failure of the pressure relief mechanism is a research direction in battery technology. Utility Model Content

[0004] This application provides a battery cell, a battery device, and an electrical device that can accurately detect electrolyte leakage caused by damage to the pressure relief mechanism.

[0005] In a first aspect, embodiments of this application provide a battery cell, including a casing, an electrode assembly, a protective film, a pressure relief mechanism, and an electrolyte detection device. The casing has a first wall with a pressure relief hole. The electrode assembly is installed inside the casing. The protective film is located on the surface of the first wall opposite to the electrode assembly and covers the pressure relief hole. The protective film is configured to be at least partially transparent. The pressure relief mechanism is installed inside the pressure relief hole. The electrolyte detection device is installed in the pressure relief hole and located between the protective film and the pressure relief mechanism. The electrolyte detection device is at least partially facing the transparent portion and is configured to change color upon contact with the electrolyte.

[0006] By adopting the above technical solution, an electrolyte detection element is installed in the pressure relief hole. The electrolyte detection element is located between the protective film and the pressure relief mechanism. When the pressure relief mechanism is damaged, the electrolyte detection element absorbs electrolyte and changes color. Since the electrolyte detection element is at least partially transparent and faces the protective film, the color change phenomenon of the electrolyte detection element can be clearly observed, thereby accurately detecting the state of electrolyte leakage caused by the failure of the pressure relief mechanism and improving the accuracy of detection.

[0007] In some embodiments of this application, the electrolyte detection element is mounted on the surface of the pressure relief mechanism facing the protective film.

[0008] By adopting the above technical solution, the electrolyte detection element is installed on the surface of the pressure relief mechanism facing the protective film. This not only facilitates the installation of the electrolyte detection element, but also allows the electrolyte leaking between the pressure relief mechanism and the protective film to easily reach the electrode liquid detection element, thereby improving detection efficiency.

[0009] In some embodiments of this application, the pressure relief mechanism has a receiving groove on the surface facing the protective film, and the electrolyte detection element is installed in the receiving groove.

[0010] By adopting the above technical solution, the electrolyte detection device is installed in the receiving groove of the pressure relief mechanism. This not only allows for the positioning and installation of the electrolyte detection device, but also reduces the space occupied by the electrolyte detection device between the pressure relief mechanism and the protective membrane to a certain extent.

[0011] In some embodiments of this application, the receiving groove is formed at the outer edge of the surface of the pressure relief mechanism facing the protective membrane.

[0012] By adopting the above technical solution, the receiving groove is opened on the outer periphery of the surface of the pressure relief mechanism, thereby reducing the impact on the performance of the pressure relief mechanism.

[0013] In some embodiments of this application, the battery cell further includes a transparent limiting member, which is connected to the pressure relief mechanism or the wall of the pressure relief hole and is used to limit the electrolyte detection element from the side opposite to the pressure relief mechanism.

[0014] By adopting the above technical solution, the electrolyte detection component is limited by a transparent limiting component, which improves the installation stability of the electrolyte detection component.

[0015] In some embodiments of this application, the depth of the receiving groove ranges from 50um to 100um.

[0016] By adopting the above technical solution, the depth of the receiving groove is designed to be 50um-100um, which facilitates processing and reduces the impact on the performance of the pressure relief mechanism.

[0017] In some embodiments of this application, the electrolyte detection element is coated and attached to the surface of the pressure relief mechanism facing the protective film.

[0018] By adopting the above technical solution, the electrolyte detection element is coated on the surface of the pressure relief mechanism, which facilitates processing and improves the connection stability between the electrolyte detection element and the pressure relief mechanism.

[0019] In some embodiments of this application, the electrolyte detection element includes a central hole, a first inner periphery surrounding the central hole, and a first outer periphery surrounding the central hole.

[0020] By adopting the above technical solution, the electrolyte detection element is designed as a closed structure with a hole in the middle. The central hole can reduce the obstruction of the pressure relief mechanism, thereby reducing the impact on the performance of the pressure relief mechanism.

[0021] In some embodiments of this application, the first outer periphery is in contact with the wall of the pressure relief hole.

[0022] By adopting the above technical solution, the first outer periphery is fitted with the hole wall of the pressure relief hole. When the edge area of ​​the pressure relief mechanism is damaged and electrolyte leakage occurs, the electrolyte can directly contact the electrolyte detection element, which improves the detection efficiency and accuracy.

[0023] In some embodiments of this application, the protective film includes a transparent film and an adhesive member. The transparent film covers the pressure relief hole, and the adhesive member is located between the transparent film and the first wall and is disposed around the pressure relief hole. The transparent film and the first wall are connected by the adhesive member, which is an annular member and has a second inner periphery.

[0024] Using the above technical solution, the protective film is designed to include a transparent film and an adhesive. The adhesive facilitates the connection between the protective film and the first wall. The second inner periphery of the adhesive is set facing the pressure relief mechanism, which makes the adhesive have a larger width and can improve the sealing performance of the connection between the adhesive and the first wall.

[0025] In some embodiments of this application, along a first direction, the distance between the first inner periphery and the wall of the pressure relief hole is L, and the distance between the second inner periphery and the wall of the pressure relief hole is N, wherein LN≥0.2mm.

[0026] By adopting the above technical solution, the LN is designed to be greater than or equal to 0.2mm, so that the first inner periphery is located within the projection range of the second inner periphery, which facilitates the observation of the electrolyte detection device.

[0027] In some embodiments of this application, the color of the surface of the adhesive member facing the transparent membrane is different from the color of the surface of the electrolyte detection member facing the transparent membrane.

[0028] By adopting the above technical solution, the surface color of the adhesive component is designed to be different from the surface color of the electrolyte detection component, which facilitates the identification of the color of the electrolyte detection component and improves the detection effect.

[0029] In some embodiments of this application, the electrolyte detection element includes a first annular portion and a second annular portion, the first annular portion being sleeved on the second annular portion, the first annular portion having a first outer periphery, and the second annular portion having a first inner periphery.

[0030] By adopting the above technical solution, the electrolyte detection element is designed as a structure consisting of multiple ring-shaped parts, and the diameter of the electrolyte detection element can be changed by adding or removing the ring-shaped parts.

[0031] In some embodiments of this application, the protective film has a through hole or slit that communicates with the pressure relief hole.

[0032] By employing the above technical solution, the protective film is provided with through holes or gaps, which can be used for auxiliary pressure relief.

[0033] In some embodiments of this application, the electrolyte detection element is configured to expand in volume upon contact with the electrolyte.

[0034] By adopting the above technical solution, the electrolyte detection element not only changes color but also undergoes volume change after contacting the electrolyte, which more intuitively reflects the damaged state of the explosion-proof valve, thereby improving the accuracy of the detection.

[0035] In some embodiments of this application, the protective film is a waterproof component.

[0036] By adopting the above technical solution, the protective membrane is designed to be waterproof, reducing the possibility of water entering the pressure relief hole through the protective membrane, thereby reducing the possibility of the electrolyte detection device changing color due to contact with external water and causing detection errors.

[0037] Secondly, embodiments of this application provide a battery device, including a battery housing and a battery cell as described in any of the above technical solutions, wherein the battery cell is installed in the battery housing.

[0038] Thirdly, embodiments of this application provide an electrical device including the battery device described in the above technical solution, wherein the battery device is used to provide electrical energy or store electrical energy. Attached Figure Description

[0039] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the embodiments of this application will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on the drawings without creative effort.

[0040] Figure 1 This is a schematic diagram of the structure of the electrical equipment provided in the embodiments of this application;

[0041] Figure 2 This is a schematic diagram of the structure of the battery device provided in the embodiments of this application;

[0042] Figure 3 This is a schematic diagram of the structure of a single battery cell provided in an embodiment of this application;

[0043] Figure 4 This is a schematic diagram of the structure of the first wall of a battery cell provided in an embodiment of this application;

[0044] Figure 5 for Figure 4 Exploded view;

[0045] Figure 6 for Figure 4 AA section diagram;

[0046] Figure 7 for Figure 6 Enlarged view of part b.

[0047] The reference numerals in the accompanying drawings for the specific embodiments are as follows:

[0048] 1000, vehicles;

[0049] 100. Battery device;

[0050] 10. Battery housing;

[0051] 11. First box;

[0052] 12. Second box;

[0053] 20. Battery cell; 21. Casing; 211. First wall; 212. Housing; 2111. Pressure relief hole; 22. Electrode assembly; 23. Protective film; 231. Transparent film; 232. Adhesive component; 2321. Second inner periphery; 24. Pressure relief mechanism; 241. Receiving tank; 25. Electrolyte detection component; 251. First inner periphery; 252. First outer periphery; 26. First terminal post; 27. Second terminal post; 28. Transparent limiting component;

[0054] 200. Controller;

[0055] 300. Motor;

[0056] X, first direction; Y, second direction; Z, third direction. Detailed Implementation

[0057] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0058] Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used in the description of this application is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms "comprising" and "having," and any variations thereof, in the description, claims, and accompanying drawings of this application are intended to cover non-exclusive inclusion. The terms "first," "second," etc., in the description, claims, or accompanying drawings of this application are used to distinguish different objects, not to describe a specific order or hierarchy.

[0059] In this application, the reference to "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment that is mutually exclusive with other embodiments.

[0060] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "attachment" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0061] 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, H and / or B can represent: H existing alone, H and B existing simultaneously, and B existing alone. Additionally, in this application, the character " / " generally indicates that the preceding and following related objects have an "or" relationship.

[0062] In the embodiments of this application, the same reference numerals denote the same components, and for the sake of brevity, detailed descriptions of the same components are omitted in different embodiments. It should be understood that the thickness, length, width, and other dimensions of various components in the embodiments of this application shown in the accompanying drawings, as well as the overall thickness, length, width, and other dimensions of the integrated device, are merely illustrative and should not constitute any limitation on this application.

[0063] In this application, "multiple" means two or more (including two).

[0064] To reduce the possibility of excessive internal pressure in battery cells during charging and discharging, the outer casing of each battery cell is equipped with a pressure relief mechanism. When the internal pressure of the battery cell is too high, the pressure relief mechanism is ruptured first to release the internal pressure of the battery cell, thereby reducing the possibility of battery safety problems.

[0065] However, damage to the pressure relief mechanism can cause electrolyte leakage and contamination, and may also lead to poor insulation and corrosion of the casing due to poor conduction between the negative terminal and the outer casing. During battery production, the pressure relief mechanism is primarily inspected visually for damage. However, when the pressure relief mechanism has edge damage or has separated from the pressure relief hole, it is difficult to detect because it is obscured by the adhesive tape around the protective film, affecting the accuracy of visual inspection.

[0066] Therefore, improving the detection accuracy of pressure relief mechanism damage or separation from pressure relief hole is an important issue in the research and development of battery devices and related components.

[0067] In view of this, this application provides a technical solution in which a visible electrolyte detection element is provided between the protective film and the pressure relief mechanism. When the pressure relief mechanism is damaged or separated from the pressure relief hole, the electrolyte detection element changes color upon contact with the electrolyte, making it easier for manual identification and thus improving the accuracy of detection.

[0068] Below, in conjunction with the appendix Figure 1-6 The battery cell, battery device, and electrical equipment provided in the embodiments of this application will be described.

[0069] The electrical equipment can include vehicles, mobile phones, portable devices, laptops, ships, spacecraft, electric toys, and power tools, etc. Vehicles can be gasoline-powered cars, natural gas-powered cars, or new energy vehicles; new energy vehicles can be pure electric vehicles, hybrid electric vehicles, or range-extended electric vehicles, etc. Spacecraft include airplanes, rockets, space shuttles, and spacecraft, etc. Electric toys include stationary or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, etc. Power tools include metal cutting power tools, grinding power tools, assembly power tools, and railway power tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete vibrators, and electric planers, etc. This application does not impose special limitations on the above-mentioned electrical equipment.

[0070] This embodiment uses a vehicle as an example of electrical equipment for illustration.

[0071] Combined with appendix Figure 1As shown, vehicle 1000 can be a gasoline-powered vehicle, a natural gas-powered vehicle, or a new energy vehicle. New energy vehicles can be pure electric vehicles, hybrid electric vehicles, or range-extended electric vehicles, etc. A battery device 100 is installed inside vehicle 1000, and the battery device 100 can be located at the bottom, front, or rear of vehicle 1000. The battery device 100 can be used to power vehicle 1000; for example, the battery device 100 can serve as the operating power source for vehicle 1000. Vehicle 1000 may also include a controller 200 and a motor 300. The controller 200 is used to control the battery device 100 to supply power to the motor 300, for example, to meet the power needs of vehicle 1000 during starting, navigation, and driving.

[0072] 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.

[0073] Combined with appendix Figure 2 As shown, this application provides a battery device 100, including a battery housing 10 and battery cells 20 installed inside the battery housing 10.

[0074] The battery device 100 mentioned in the embodiments of this application may include one or more battery cell assemblies for providing voltage and capacity. The battery cell assembly may include multiple battery cells 20, which are connected in series, parallel, or mixed connections via a busbar. The battery cells 20 are suitable for batteries and electrical devices that use batteries.

[0075] In some embodiments, a battery cell assembly is typically formed by arranging multiple battery cells 20; as an example, a battery cell assembly can be a battery module, which is formed by arranging and fixing multiple battery cells 20 into a single module. As an example, a battery module can be formed by bundling multiple battery cells 20 together with cable ties.

[0076] In some embodiments, the battery device 100 may be a battery pack, which includes a battery housing 10 and one or more battery cell assemblies, the battery cell assemblies being housed in the battery housing 10.

[0077] As an example, the battery cell assembly can be a battery module, which can be housed in the battery housing 10 by fixing the battery module in the battery housing 10.

[0078] As an example, the battery cell assembly can also be housed in the battery housing 10 by directly fixing multiple battery cells 20 to the battery housing 10.

[0079] The battery housing 10 provides a space for housing the battery cells 20, and the battery housing 10 can adopt various structures. In some embodiments, the battery housing 10 may include a first housing 11 and a second housing 12, which overlap each other, and together define a space for housing the battery cells 20. Both the first housing 11 and the second housing 12 can be hollow structures with one open end, with the second housing 12 covering the open side of the first housing 11, so that the first housing 11 and the second housing 12 together define the space; alternatively, the second housing 12 can be a plate-like structure, and the first housing 11 can be a hollow structure with one open side, with the open side of the second housing 12 covering the open side of the first housing 11. Of course, the battery housing 10 formed by the first housing 11 and the second housing 12 can be of various shapes, such as a cylinder, a cuboid, etc.

[0080] As an example, the battery box 10 can be part of the chassis structure of the vehicle 1000. For example, the top cover of the battery box 10 can be at least part of the floor of the vehicle 1000, or the frame of the battery box 10 can be at least part of the crossbeams and longitudinal beams of the vehicle 1000.

[0081] In some embodiments, battery device 100 refers to an energy storage device, which includes a battery housing 10, and at least one side of the battery housing 10 has a door. Energy storage devices include energy storage containers, energy storage cabinets, etc.

[0082] Combined with appendix Figure 3-5 As shown, this application embodiment provides a battery cell 20, including a housing 21, an electrode assembly 22, a protective film 23, a pressure relief mechanism 24, and an electrolyte detection element 25. The housing 21 has a first wall 211 with a pressure relief hole 2111. The electrode assembly 22 is installed inside the housing 21. The protective film 23 is located on the surface of the first wall 211 away from the electrode assembly 22 and covers the pressure relief hole 2111. The protective film 23 is configured to be at least partially transparent. The pressure relief mechanism 24 is installed inside the pressure relief hole 2111. The electrolyte detection element 25 is installed in the pressure relief hole 2111 and located between the protective film 23 and the pressure relief mechanism 24. The electrolyte detection element 25 is at least partially facing the transparent portion and is configured to change color after contact with the electrolyte.

[0083] The electrode assembly 22 and electrolyte (not shown) are located inside the housing 21. The electrode assembly 22 includes a positive electrode, a negative electrode, and a separator. The battery cell 20 mainly operates by the movement of metal ions between the positive and negative electrode. The positive electrode includes a positive current collector and a positive active material layer, the positive active material layer being coated on the surface of the positive current collector; the positive current collector includes a positive electrode coating area and a positive electrode tab connected to the positive electrode coating area, the positive electrode coating area being coated with the positive active material layer, and the positive electrode tab not being coated with the positive active material layer.

[0084] Taking a lithium-ion battery cell 20 as an example, the positive electrode current collector can be made of aluminum, and the positive electrode active material layer includes positive electrode active material, which can be lithium cobalt oxide, lithium iron phosphate, ternary lithium, or lithium manganese oxide, etc. The negative electrode includes a negative electrode current collector and a negative electrode active material layer, with the negative electrode active material layer coated on the surface of the negative electrode current collector. The negative electrode current collector includes a negative electrode coating area and a negative electrode tab connected to the negative electrode coating area. The negative electrode coating area is coated with the negative electrode active material layer, while the negative electrode tab is not coated with the negative electrode active material layer. The negative electrode current collector can be made of copper, and the negative electrode active material layer includes negative electrode active material, which can be carbon or silicon, etc. The separator can be made of PP (polypropylene) or PE (polyethylene), etc.

[0085] The housing 21 includes a housing 212 and an end cap. The housing 212 has an opening, through which the electrode assembly 22 is mounted. The end cap is mounted at the opening to close it.

[0086] In some embodiments, the first wall 211 may be an end cap, or it may be a side wall or bottom wall of the housing 212. This embodiment is described using the first wall 211 as an end cap as an example.

[0087] The first wall 211 is provided with a first electrode post 26 and a second electrode post 27 connected to the electrode assembly 22. One of the first electrode post 26 and the second electrode post 27 is a positive electrode post, and the other is a negative electrode post.

[0088] The first wall 211 has a pressure relief hole 2111. The pressure relief hole 2111 is a through hole structure, and its shape can be circular, elliptical, rectangular, etc. This embodiment will not list them one by one.

[0089] The protective film 23 is located on the surface of the first wall 211 away from the electrode assembly 22 and covers the pressure relief hole 2111. The protective film 23 is used to prevent foreign objects from entering the pressure relief hole 2111 and contaminating the electrolyte detection element 25 or the pressure relief mechanism 24.

[0090] The protective film 23 is configured to be at least partially transparent, meaning that the protective film 23 can be wholly or partially transparent, allowing the pressure relief mechanism 24 and the electrolyte detection element 25 located below it to be observed.

[0091] The pressure relief mechanism 24 is installed inside the pressure relief hole 2111. The pressure relief mechanism 24 is a safety device, mainly used to quickly release gas when the internal pressure of the battery cell 20 rises abnormally, so as to prevent the battery cell 20 from exploding or rupturing due to overpressure.

[0092] The pressure relief mechanism 24 typically includes a pre-marked weak area or a spring mechanism that, when the internal pressure exceeds a set threshold, breaks at the weak point or the spring is pushed open to form an exhaust channel to release the pressure.

[0093] Unlike related technologies that only observe the surface of the pressure relief mechanism 24 facing the protective film 23 to determine whether the pressure relief mechanism 24 is damaged, this embodiment installs an electrolyte detection element 25 in the pressure relief hole 2111 and between the protective film 23 and the pressure relief mechanism 24. The electrolyte detection element 25 is at least partially facing the transparent part and is configured to change color after contact with the electrolyte.

[0094] The electrolyte detection element 25 may include the following materials: polymeric materials, such as polyaniline (PANI), whose main chain conjugated structure undergoes energy level changes during redox reactions, resulting in reversible color changes (e.g., from yellow to purple); polypyrrole (PPy) and polythiophene (PTh), where changes in the electronic structure of the conjugated chains lead to significant color changes (e.g., from yellow to bluish-black); nitrile rubber (NBR), which shows a noticeable color change and swelling upon contact with the electrolyte; cellulose paper, which darkens in color and swells after absorbing the electrolyte; inorganic materials, such as Prussian blue (PB), whose crystal structure changes color with oxidation state (e.g., from blue to transparent) and expands in volume when reacting with the electrolyte; nickel oxide (NiO), which changes from transparent to dark in the electrolyte; and tungsten oxide (WO3), whose color changes through the insertion and extraction of lithium ions.

[0095] This embodiment will not list too many examples. Any material that changes color upon contact with liquid (including electrolyte) can be used as an optional material for the electrolyte detection element 25 in this embodiment.

[0096] In this way, when the pressure relief mechanism 24 is damaged, the electrolyte detection element 25 absorbs the electrolyte and changes color. Since the electrolyte detection element 25 is at least partially exposed to the transparent structure of the protective film 23, the color change of the electrolyte detection element 25 can be clearly observed, thereby accurately detecting the state of electrolyte leakage caused by the failure of the pressure relief mechanism 24 and improving the accuracy of detection.

[0097] Combined with appendix Figure 5-7 As shown, in some other examples, the electrolyte detection element 25 may optionally be mounted on the surface of the pressure relief mechanism 24 facing the protective film 23.

[0098] The pressure relief mechanism 24 has a surface facing the electrode assembly 22 and a surface away from the electrode assembly 22. The surface of the pressure relief mechanism 24 away from the electrode assembly 22 is also the surface of the pressure relief mechanism 24 facing the protective film 23.

[0099] If the electrolyte detection element 25 is installed on the surface of the pressure relief mechanism 24 facing the electrode assembly 22 (the surface away from the protective film 23), the discoloration of the electrolyte detection element 25 cannot be observed, and the electrolyte detection element 25 will directly contact the electrode liquid around the electrode assembly 22, thus failing to achieve the detection function.

[0100] Therefore, in this embodiment, the electrolyte detection element 25 is installed on the surface of the pressure relief mechanism 24 facing the protective film 23. In this way, not only is it convenient to install the electrolyte detection element 25, but when the pressure relief mechanism 24 is damaged, the electrolyte will leak through the pressure relief mechanism 24 to the space between the pressure relief mechanism 24 and the protective film 23, thereby reaching the electrolyte detection element 25. The electrolyte detection element 25 will change color directly after contacting the electrolyte to indicate that the pressure relief mechanism 24 is damaged.

[0101] Furthermore, compared to a method that leaves a gap between the electrolyte detection element 25 and the pressure relief mechanism 24, this embodiment connects the electrolyte detection element 25 and the pressure relief mechanism 24. The electrolyte leaking through the pressure relief mechanism 24 can come into contact with the electrolyte detection element 25 more quickly, thereby improving detection efficiency.

[0102] Combined with appendix Figure 6 and 7 As shown, in some examples, optionally, the pressure relief mechanism 24 has a receiving groove 241 on the surface facing the protective film 23, and the electrolyte detection element 25 is installed in the receiving groove 241.

[0103] The receiving groove 241 of this embodiment can be formed by means of laser engraving, mechanical stamping, chemical etching, precision milling or in-mold forming, etc. This embodiment will not list the forming methods of the receiving groove 241 in detail.

[0104] The electrolyte detection element 25 is installed in the receiving tank 241. The electrolyte detection element 25 can be completely installed in the receiving tank 241. In this case, the surface of the electrolyte detection element 25 facing the protective film 23 does not protrude from the surface of the pressure relief mechanism 24 facing the protective film 23.

[0105] Alternatively, part of the electrolyte detection element 25 can be installed in the receiving tank 241, in which case the surface of the electrolyte detection element 25 facing the protective film 23 protrudes from the surface of the pressure relief mechanism 24 facing the protective film 23.

[0106] Both of the above methods can achieve the installation of the electrolyte detection element 25 in the receiving tank 241, and the receiving tank 241 can be used to limit and fix the electrolyte detection element 25 along the first direction X and the second direction Y in the figure.

[0107] By adopting the above structure, the electrolyte detection element 25 is installed in the receiving groove 241 of the pressure relief mechanism 24. This not only allows for the positioning and installation of the electrolyte detection element 25, but also reduces the space occupied by the electrolyte detection element 25 between the pressure relief mechanism 24 and the protective membrane 23 to a certain extent.

[0108] In some examples, the receiving groove 241 is optionally formed at the outer edge of the surface of the pressure relief mechanism 24 facing the protective membrane 23.

[0109] Taking the pressure relief mechanism 24 as a circular or elliptical shape as an example, a receiving groove 241 can be opened on the outer circumferential edge of the pressure relief mechanism 24 facing the protective film 23. The receiving groove 241 only has a side wall on the inner ring side, and the outer ring of the receiving groove 241 may not have a side wall. This allows the electrolyte that enters the surface of the pressure relief mechanism 24 facing the protective film 23 through the edge damage to reach the electrolyte detection element 25 in the receiving groove 241 directly, thereby further improving the detection efficiency and accuracy.

[0110] Furthermore, since the core area (such as the scoring line or weak area) of the pressure relief mechanism 24 is generally inside its edge, the gas needs to be released quickly along the designed path after the pressure relief mechanism 24 is opened. If the receiving tank 241 is located in the core area, it may form an unintended leakage channel, affecting the pressure relief efficiency. The tanks on the outer periphery are usually offset from the pressure relief direction to reduce interference with the airflow organization.

[0111] The material integrity of the core area is crucial to the fatigue life of the pressure relief mechanism 24, while the slotting on the outer periphery can reduce the risk of crack propagation caused by cyclic charging and discharging or temperature changes.

[0112] Therefore, by opening the receiving groove 241 on the outer periphery of the surface of the pressure relief mechanism 24, the impact on the performance of the pressure relief mechanism 24 can be reduced or even eliminated.

[0113] In some examples, the battery cell 20 may optionally include a transparent limiting member 28, which is connected to the wall of the pressure relief mechanism 24 or the pressure relief hole 2111 and is used to limit the electrolyte detection member 25 from the side opposite to the pressure relief mechanism 24.

[0114] The transparent limiting element can be made of polymer materials, such as PTFE (polytetrafluoroethylene), PET (polyester), PMMA (polymethyl methacrylate / acrylic) or PC (polycarbonate), etc., which will not be listed one by one in this embodiment.

[0115] By adopting the above technical solution, the electrolyte detection component 25 is limited by the transparent limiting component 28, which improves the installation stability of the electrolyte detection component 25.

[0116] In some examples, the depth of the receiving groove 241 is optionally in the range of 50um-100um.

[0117] The depth of the receiving groove 241 can be 50um, 60um, 70um, 80um, 90um and 100um, which will not be listed one by one in this embodiment.

[0118] The depth of the receiving groove 241 is designed to be 50um-100um. This depth range ensures that the electrolyte detection element 25 is firmly embedded, avoiding both shallow depth that would result in insecure fixation and excessive depth that would affect the structural strength of the pressure relief mechanism 24 or the gas release path.

[0119] Moreover, the receiving groove 241 of the above depth only acts on the edge and non-core areas, and hardly interferes with the mechanical properties of the core area (such as the scoring line) of the pressure relief mechanism 24, which can meet the pressure relief threshold and burst consistency.

[0120] In addition, a groove depth of 50μm-100μm is suitable for precision processing such as laser engraving and chemical etching, which is easy to mass-produce and cost-controllable, while maintaining the flatness of the groove wall and reducing stress concentration.

[0121] In some examples, the electrolyte detection element 25 is optionally coated on the surface of the pressure relief mechanism 24 facing the protective film 23.

[0122] For example, the electrolyte detection element 25 can be coated and connected to the bottom wall of the above-mentioned receiving tank 241. Alternatively, the receiving tank 241 can be omitted, and the electrolyte detection element 25 can be directly coated and connected to the surface of the pressure relief mechanism 24 facing the protective film 23.

[0123] Coating the electrolyte detection element 25 onto the pressure relief mechanism 24 facilitates processing and improves the connection stability between the electrolyte detection element 25 and the pressure relief mechanism 24.

[0124] Moreover, compared to coating and attaching the electrolyte detection element 25 to the aforementioned receiving tank 241, directly coating and attaching the electrolyte detection element 25 to the surface of the pressure relief mechanism 24 has at least the following advantages: it eliminates the need for grooving processing, reduces the requirement for precision machinery or laser processes, lowers production complexity and manufacturing costs, and is especially suitable for large-scale mass production. It eliminates the need for cutting the pressure relief mechanism 24, maintaining the overall structural integrity of the pressure relief mechanism 24 and not interfering with its performance.

[0125] Combined again with the appendix Figure 5-7As shown, in some examples, the electrolyte detection element 25 optionally includes a central hole, a first inner periphery 251 surrounding the central hole, and a first outer periphery 252 surrounding the central hole.

[0126] When the pressure relief mechanism 24 has a receiving groove 241, the surface of the pressure relief mechanism 24 facing the protective film 23 protrudes from the receiving groove 241 and is located in the central hole. Therefore, the central hole is not marked in the attached drawings in this embodiment.

[0127] The above structure makes the electrolyte detection element 25 a closed structure. It should be noted that the closed structure can be a ring, an elliptical ring, a rectangle, a triangle, etc.

[0128] The annular or other closed structure can cover the entire perimeter of the pressure relief mechanism. No matter which direction the electrolyte leaks from (such as local wetting caused by uneven internal battery pressure), it can be captured by the detection element, further improving the detection accuracy.

[0129] The closed structure, such as the ring, can avoid the core position of the weak area (such as the scoring line) of the pressure relief mechanism 24, and is only arranged on the non-pressure-bearing edge or periphery, so as to ensure that the pressure relief action is not interfered with by the detection component.

[0130] In addition, when the battery cell 20 is depressurized, the detection element of the closed structure can break synchronously with the deformation of the depressurization mechanism 24, reducing the possibility of residual structure blocking the depressurization channel.

[0131] In some examples, the first outer periphery 252 may optionally be fitted against the wall of the pressure relief hole 2111.

[0132] The reason for adopting this design is that most of the damage to the pressure relief mechanism 24 occurs at its edges. Therefore, the preferred escape path for electrolyte vapor or thermal runaway gas is between the edge of the pressure relief mechanism 24 and the wall of the pressure relief hole 2111. When the first outer periphery 252 of the electrolyte detection element 25 is in contact with the wall of the pressure relief hole 2111, it can contact the leaking substance immediately, shortening the response time. Moreover, the gas / liquid flow velocity is high near the pressure relief hole 2111, and the contact design allows the electrolyte detection element 25 to fully contact the electrolyte.

[0133] Therefore, in this embodiment, the first outer periphery 252 is fitted with the hole wall of the pressure relief hole 2111. When the edge area of ​​the pressure relief mechanism 24 is damaged and electrolyte leakage occurs, the electrolyte can directly contact the electrolyte detection element 25, which improves the detection efficiency and accuracy.

[0134] Combined again with the appendix Figure 6 and 7As shown, in some examples, optionally, the protective film 23 includes a transparent film 231 and an adhesive 232, the transparent film 231 covering the pressure relief hole 2111, the adhesive 232 being located between the transparent film 231 and the first wall 211 and surrounding the pressure relief hole 2111, the transparent film 231 and the first wall 211 being connected by the adhesive 232, the adhesive 232 having a second inner periphery 2321 facing the pressure relief mechanism 24.

[0135] The material of the transparent film 231 may include polyimide (PI), polyethylene terephthalate (PET), polypropylene (PP), polyethylene (PE), polyvinyl chloride (PVC), polyvinylidene fluoride (PVDF), or polytetrafluoroethylene (PTFE), etc., which will not be listed one by one in this embodiment.

[0136] The adhesive 232 can be colored adhesive paper, such as polyimide (PI) tape, polyethylene terephthalate (PET) tape, or fluorinated tape (such as PTFE tape). Of course, in addition to colored adhesive paper, double-sided tape, hot melt adhesive, or epoxy resin adhesive can also be used to bond the diaphragm and the first wall 211.

[0137] The transparent diaphragm 231 is slightly larger than the pressure relief hole 2111, so that the transparent diaphragm 231 can cover the pressure relief hole 2111. The adhesive 232 can be a closed-loop structure surrounding the pressure relief hole 2111, for example, the adhesive 232 can be annular.

[0138] The adhesive 232 has a second inner periphery 2321 facing the pressure relief mechanism 24. This means that the second inner periphery 2321 of the adhesive 232 extends into the pressure relief hole 2111 along the third direction Z in the figure within the projection range of the transparent diaphragm 231. The third direction Z is perpendicular to the first direction X and the second direction Y, respectively. The third direction Z can be understood as the arrangement direction of the protective film 23 to the adhesive 232.

[0139] The second inner periphery 2321 of the adhesive 232 is positioned facing the pressure relief mechanism 24, which makes the adhesive 232 have a larger width, increases the bonding area, improves adhesion, and reduces the possibility of the transparent film 231 loosening due to vibration or temperature changes.

[0140] Moreover, wider colored adhesive tape can distribute sealing pressure more evenly, reducing the risk of localized air leakage and preventing moisture and dust from entering the battery.

[0141] In addition, wider colored adhesive tape ensures that the diaphragm edges are firmly secured, allowing it to rupture precisely under the set pressure, reducing the possibility of pressure relief failure due to premature or uneven stress.

[0142] In addition, it can reduce interference from adhesive tape fragments, and the 23 protective films will break first, ensuring unobstructed pressure relief channels and improving explosion-proof consistency.

[0143] Combined with appendix Figure 7 As shown, in some examples, optionally, along the first direction X, the distance between the first inner periphery 251 and the wall of the pressure relief hole 2111 is L, and the distance between the second inner periphery 2321 and the wall of the pressure relief hole 2111 is N, where LN≥0.2mm.

[0144] LN can be 0.2mm, 0.5mm, 1mm, 1.5mm and 2mm, etc., which will not be listed one by one in this embodiment.

[0145] When LN is greater than or equal to 0.2 mm, the first inner periphery 251 can be located within the projection range of the second inner periphery 2321, which facilitates the observation of the electrolyte detection element 25.

[0146] In some examples, optionally, the color of the surface of the adhesive member facing the transparent membrane is different from the color of the surface of the electrolyte detection member facing the transparent membrane.

[0147] The surface color of the adhesive component is designed to be different from that of the electrolyte detection component, which facilitates the identification of the electrolyte detection component's color and improves the detection effect.

[0148] In some examples, the electrolyte detection element may optionally include a first annular portion and a second annular portion (not shown in the figure), the first annular portion being sleeved on the second annular portion, the first annular portion having a first outer periphery, and the second annular portion having a first inner periphery.

[0149] The first annular portion is fitted onto the second annular portion, either directly or indirectly through other annular portions in the middle (such as the third annular portion).

[0150] Therefore, in addition to the first annular portion and the second annular portion, the electrolyte detection element may also include other annular portions.

[0151] The electrolyte detection element is designed as a structure consisting of multiple ring-shaped sections, and the diameter of the electrolyte detection element can be varied by adding or removing ring-shaped sections.

[0152] In some examples, the protective membrane 23 may optionally have a through hole or slit communicating with the pressure relief hole 2111.

[0153] The protective film 23 can have through holes with small pores, such as through holes with a diameter of less than 0.1 mm, or gaps with a width of less than 0.1 mm.

[0154] Through holes / gap can serve as auxiliary pressure relief channels. When the internal pressure of the battery cell 20 increases sharply (such as in the early stage of thermal runaway), the gas can be quickly released through the preset holes / gap, avoiding pressure accumulation that could cause the casing 212 to burst and reducing the risk of explosion.

[0155] Moreover, by adjusting the size, number, or slot layout of the through holes (such as star-shaped or annular pre-cracked slots), the pressure relief threshold can be precisely controlled, enabling the explosion-proof valve to be triggered within the set pressure range, thus reducing the possibility of premature or late pressure relief.

[0156] In addition, when a traditional non-porous transparent diaphragm 231 breaks, fragments may be generated that block the pressure relief channel, while pre-drilled holes / slits can guide the transparent diaphragm 231 to break regularly along the designed path, improving the unobstructed flow of the pressure relief channel.

[0157] In addition, some of the pressure can be released in advance through the through holes / gap, which can reduce the overall stress on the membrane and reduce the risk of adhesive layer delamination, making it especially suitable for the extreme operating conditions of high energy density batteries.

[0158] In some examples, the electrolyte detection element 25 is optionally configured to expand in volume upon contact with the electrolyte.

[0159] In this way, the electrolyte detection element 25 not only changes color but also changes volume after coming into contact with the electrolyte, which more intuitively reflects the damaged state of the explosion-proof valve, thereby improving the accuracy of the detection.

[0160] There are several ways to design the electrolyte detection element 25 so that it changes color and expands upon contact with the electrolyte. For example, the electrolyte detection element 25 can be made of a material that changes color and expands upon contact with the electrolyte, such as nitrile rubber (NBR), natural rubber (NR), polyurethane (PU), certain thermoplastic elastomers (TPE), unmodified epoxy resin, silicone rubber (SR), polyvinyl chloride (PVC), polyvinyl butyral (PVB), polyamide (PA), styrene-butadiene rubber (SBR), etc.

[0161] Alternatively, the electrolyte detection element 25 can be designed to include an integrally connected color-changing part and a deformation part (not shown in the figure), wherein the color-changing part is configured to change color after contact with the electrolyte, and the deformation part is configured to expand in volume after contact with the electrolyte.

[0162] The color-changing part and the deformation part can be combined in various ways. For example, the materials of the two parts can be mixed together by heating, or they can be set together by interlocking with each other, or the color-changing part can be wrapped around the deformation part, as long as it does not affect the function of the two parts.

[0163] The materials for the color-changing part can include polycarbonate (PC), polyphenylene sulfide (PPS), polyether ether ketone (PEEK), and other materials that only change color and do not expand when exposed to electrolyte.

[0164] The material of the deformable part can include polypropylene (PP), polyethylene (PE), polyisobutylene (PIB), and other materials that only expand and do not change color when exposed to electrolyte.

[0165] In some examples, the protective film is optionally waterproof.

[0166] The protective membrane is designed to be waterproof, reducing the possibility of water entering the pressure relief hole through the protective membrane, thereby reducing the possibility of the electrolyte detection component changing color due to contact with external water and causing detection errors.

[0167] There are various structural forms for waterproof protective films. For example, the protective film itself can be made of waterproof and transparent materials (such as polyethylene and other plastics), or a waterproof layer can be coated on the surface of the protective film.

[0168] 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.

[0169] Please see the appendix Figure 1-7As shown, this application embodiment provides a battery cell 20, including a housing 21, an electrode assembly 22, a protective film 23, a pressure relief mechanism 24, and an electrolyte detection element 25. The housing 21 has a first wall 211 with a pressure relief hole 2111. The electrode assembly 22 is installed inside the housing 21. The protective film 23 is located on the surface of the first wall 211 facing away from the electrode assembly 22 and covers the pressure relief hole 2111. The protective film 23 is configured to be at least partially transparent. The pressure relief mechanism 24 is installed inside the pressure relief hole 2111. The electrolyte detection element 25 is installed in the pressure relief hole 2111 and located between the protective film 23 and the pressure relief mechanism 24. The electrolyte detection element 25 is at least partially facing the transparent portion and is configured to change color after contact with electrolyte. The electrolyte detection element 25 is installed on the surface of the pressure relief mechanism 24 facing the protective film 23. The pressure relief mechanism 24 has a receiving groove 241 on its surface facing the protective film 23, and the electrolyte detection element 25 is installed in the receiving groove 241. The receiving groove 241 is located at the outer edge of the surface of the pressure relief mechanism 24 facing the protective film 23. The battery cell 20 also includes a transparent limiting member 28, which is connected to the wall of the pressure relief mechanism 24 or the pressure relief hole 2111 and is used to limit the side of the electrolyte detection element 25 facing away from the pressure relief mechanism 24. The depth of the receiving groove 241 is 50um-100um. The electrolyte detection element 25 is coated and connected to the surface of the pressure relief mechanism 24 facing the protective film 23. The electrolyte detection element 25 includes a central hole, a first inner periphery 251 surrounding the central hole, and a first outer periphery 252 surrounding the central hole. The first outer periphery 252 is in contact with the wall of the pressure relief hole 2111. The protective film 23 includes a transparent film 231 and an adhesive member 232. The transparent film 231 covers the pressure relief hole 2111. The adhesive member 232 is located between the transparent film 231 and the first wall 211 and is disposed around the pressure relief hole 2111. The transparent film 231 and the first wall 211 are connected by the adhesive member 232. The adhesive member 232 is annular and has a second inner periphery 2321. Along the first direction X, the distance between the first inner periphery 2321 and the hole wall of the pressure relief hole 2111 is L, and the distance between the second inner periphery 2321 and the hole wall of the pressure relief hole 2111 is N, where LN ≥ 0.2 mm. The color of the surface of the adhesive member 232 facing the transparent film 231 is different from the color of the surface of the electrolyte detection element 25 facing the transparent film 231. The electrolyte detection element 25 includes a first annular portion and a second annular portion, with the first annular portion sleeved on the second annular portion. The first annular portion has a first outer periphery 252, and the second annular portion has a first inner periphery 251. The protective membrane 23 has a through hole or slit communicating with the pressure relief hole 2111. The electrolyte detection element 25 is configured to expand in volume upon contact with the electrolyte. The protective membrane 23 is waterproof.

[0170] Combined again with the appendix Figure 2As shown, based on the aforementioned battery cell 20, this application embodiment provides a battery device 100, including a battery housing 10 and the aforementioned battery cell 20, wherein the battery cell 20 is installed inside the battery housing 10.

[0171] Combined again with the appendix Figure 1 As shown, based on the battery device 100 described above, this application embodiment provides an electrical device including the battery device 100 of the above technical solution, the battery device 100 being used to provide electrical energy or store electrical energy.

[0172] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended 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 they can still modify the technical solutions described in the foregoing embodiments, or make equivalent substitutions for the intermediate technical features. However, these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application.

Claims

1. A battery cell, characterized in that, include: The outer casing has a first wall, and the first wall has a pressure relief hole; Electrode assemblies are installed inside the housing; A protective film is located on the surface of the first wall opposite to the electrode assembly and covers the pressure relief hole, the protective film being configured to be at least partially transparent; The pressure relief mechanism is installed inside the pressure relief hole; as well as An electrolyte detection element is installed in the pressure relief hole and located between the protective film and the pressure relief mechanism. The electrolyte detection element is at least partially facing the transparent portion and is configured to change color upon contact with the electrolyte.

2. The battery cell according to claim 1, characterized in that, The electrolyte detection element is mounted on the surface of the pressure relief mechanism facing the protective membrane.

3. The battery cell according to claim 2, characterized in that, The pressure relief mechanism has a receiving groove on the surface facing the protective film, and the electrolyte detection element is installed in the receiving groove.

4. The battery cell according to claim 3, characterized in that, The receiving groove is located at the outer edge of the surface of the pressure relief mechanism facing the protective membrane.

5. The battery cell according to claim 4, characterized in that, The battery cell also includes a transparent limiting member, which is connected to the pressure relief mechanism or the wall of the pressure relief hole and is used to limit the electrolyte detection element from the side opposite to the pressure relief mechanism.

6. The battery cell according to claim 3, characterized in that, The depth of the receiving groove ranges from 50um to 100um.

7. The battery cell according to claim 2, characterized in that, The electrolyte detection element is coated and attached to the surface of the pressure relief mechanism facing the protective film.

8. The battery cell according to any one of claims 1-7, characterized in that, The electrolyte detection element includes a central hole, a first inner periphery surrounding the central hole, and a first outer periphery surrounding the central hole.

9. The battery cell according to claim 8, characterized in that, The first outer periphery is in contact with the wall of the pressure relief hole.

10. The battery cell according to claim 9, characterized in that, The protective film includes a transparent film and an adhesive. The transparent film covers the pressure relief hole, and the adhesive is located between the transparent film and the first wall and is disposed around the pressure relief hole. The transparent film and the first wall are connected by the adhesive. The adhesive is annular and has a second inner periphery.

11. The battery cell according to claim 10, characterized in that, Along the first direction, the distance between the first inner periphery and the wall of the pressure relief hole is L, and the distance between the second inner periphery and the wall of the pressure relief hole is N, where LN≥0.2mm.

12. The battery cell according to claim 10, characterized in that, The color of the surface of the adhesive member facing the transparent membrane is different from the color of the surface of the electrolyte detection member facing the transparent membrane.

13. The battery cell according to claim 8, characterized in that, The electrolyte detection element includes a first annular portion and a second annular portion, the first annular portion being sleeved on the second annular portion, the first annular portion having a first outer periphery, and the second annular portion having a first inner periphery.

14. The battery cell according to any one of claims 1-7, characterized in that, The protective film has through holes or gaps that communicate with the pressure relief hole.

15. The battery cell according to any one of claims 1-7, characterized in that, The electrolyte detection element is configured to expand in volume upon contact with the electrolyte.

16. The battery cell according to any one of claims 1-7, characterized in that, The protective film is a waterproof component.

17. A battery device, characterized in that, It includes a battery housing and a battery cell as described in any one of claims 1-16, wherein the battery cell is installed in the battery housing.

18. An electrical appliance, characterized in that, Includes the battery device as described in claim 17, wherein the battery device is used to provide electrical energy or store electrical energy.

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