Battery explosion-proof structure and power battery

Abstract

The present application discloses a battery explosion-proof structure and a power battery. The explosion-proof structure includes a first protective layer, a metal layer, and a second protective layer stacked in sequence; wherein the first protective layer and the second protective layer are polyester material pieces; the metal layer is a lithium-containing metal material, and the metal layer is used to be attached to the aluminum cover plate, and forms a diffusion effect with the aluminum cover plate to reduce the structural strength of the position where the aluminum cover plate and the metal layer are attached, and form a blasting area; when the gas pressure in the power battery reaches the opening pressure of the explosion-proof structure, the gas in the power battery breaks through the explosion-proof structure to discharge the gas in the power battery. The explosion-proof structure of the present application reduces the structural strength of the position where the aluminum cover plate and the metal layer are attached by attaching the metal layer to the aluminum cover plate to form a diffusion effect, so that a weak blasting area is formed at the position of the patch. There is no need to modify other structures of the power battery, the manufacturing process is simple, the cost is low, and the failure rate is low.

Description

Technical Field

[0001] The present application relates to the technical field of vehicle batteries, and more specifically, to a battery explosion-proof structure and a power battery having the battery explosion-proof structure. Background Art

[0002] The explosion-proof structure of a battery cell is typically installed as a separate component, along with other components, as a protective device for the battery cell. When the internal pressure of the battery cell reaches a certain level, the gases generated within must be released to prevent the entire cell from exploding. This is done by rupturing the explosion-proof structure, acting as a weak point in the cell, when internal pressure reaches a certain level. This releases the gases within the cell, protects other battery components, and enhances the safety of the cell and the entire battery pack.

[0003] In the prior art, the main ways to arrange explosion-proof structures on battery cells are to laminate a thin film on the cover plate or to use an explosion-proof needle structure. Both of the above methods require substantial modification of the original structure in order to reduce the gas tolerance strength at the packaging position of the explosion-proof structure. For example, hollowing out or etching the battery cell shell, making indentations or notches on the battery cell shell, adding various complex components, etc. This not only reduces the structural strength of the shell at that position itself, but also increases the assembly cost due to the complex structure. The complicated process will also increase the failure rate. Even in the case of external factors (such as collision or extrusion), the explosion-proof structure may be easily damaged by mistake, which will have an adverse effect on the performance and safety of the battery cell. Summary of the Invention

[0004] One purpose of the present application is to provide a new technical solution for a battery explosion-proof structure and a power battery, which can at least solve the problem in the prior art that the original structure needs to be significantly modified in order to reduce the gas tolerance strength at the structural packaging position of the explosion-proof structure.

[0005] According to a first aspect of the present application, a battery explosion-proof structure is provided, which is used to be attached to a power battery, and the explosion-proof structure includes a first protective layer, a metal layer, and a second protective layer stacked in sequence; wherein, the first protective layer and the second protective layer are polyester material pieces, and the first protective layer can be torn off on the metal layer; the metal layer is a lithium-containing metal material, and the metal layer is used to contact and be attached to the aluminum cover plate of the power battery, and form a diffusion effect with the aluminum cover plate to reduce the structural strength of the aluminum cover plate at the attachment position of the metal layer and form a blasting area; when the gas pressure in the power battery reaches the opening pressure of the explosion-proof structure, the gas in the power battery breaks through the explosion-proof structure to discharge the gas in the power battery.

[0006] Optionally, the metal layer is a lithium-containing alloy, a mixture of at least two lithium-containing alloys, a passivated lithium metal material, or a mixture including a passivated lithium metal material.

[0007] Optionally, the metal layer includes one or more of lithium aluminum alloy, lithium carbon alloy, lithium silicon alloy, lithium germanium alloy, lithium tin alloy, lithium gallium alloy, lithium indium alloy, lithium bismuth alloy, lithium calcium alloy, lithium magnesium alloy and lithium antimony alloy.

[0008] Optionally, the metal layer includes a ternary alloy or a ternary alloy of more than one element consisting of a first main group element, a second main group element, a third main group element, a transition metal element, a rare earth metal element and lithium.

[0009] Optionally, the explosion-proof structure has a thickness of 50 μm-500 μm, wherein the metal layer has a thickness of 15 μm-450 μm.

[0010] Optionally, the opening pressure of the explosion-proof structure is 0.2MPa-1.2MPa.

[0011] Optionally, the patch area of ​​the explosion-proof structure is 10mm 2 -3000mm 2 .

[0012] Optionally, the first protective layer and the second protective layer are respectively adhesively connected to the metal layer, and the first protective layer and the second protective layer are polymer substrates and adhesive layers adhered to the explosion-proof structure.

[0013] According to a second aspect of the present application, a power battery is provided, comprising: a shell, wherein a accommodating cavity is defined therein, and the shell has an aluminum cover plate to cover the accommodating cavity; a battery cell, wherein the battery cell is located in the accommodating cavity; the battery explosion-proof structure described in the above embodiment, wherein after the first protective layer of the explosion-proof structure is torn off, the metal layer faces the aluminum cover plate and is attached to the aluminum cover plate, and the metal layer and the aluminum cover plate form a diffusion effect to reduce the structural strength of the position where the aluminum cover plate and the metal layer are attached, and form a blasting area; when the gas pressure in the power battery reaches the pressure threshold of the blasting area, the gas in the power battery breaks through the blasting area to discharge the gas in the power battery.

[0014] Optionally, the ratio of the thickness of the aluminum cover plate to the thickness of the metal layer is 0.1-100.

[0015] Optionally, the pressure threshold of the blasting area is 0.22 MPa-1.2 MPa, and the time for the metal layer and the aluminum cover plate to form a diffusion effect is 30 minutes to 72 hours.

[0016] According to one embodiment of the present disclosure, the explosion-proof structure is a patch structure which is stacked by a first protective layer, a metal layer and a second protective layer. The first protective layer can be torn off, and the metal layer is made of a lithium-containing metal material. By attaching the metal layer to the aluminum cover to form a diffusion effect, the structural strength of the position where the aluminum cover and the metal layer are attached is reduced, so that a weak blasting area is formed at the patch position. When the gas pressure in the power battery reaches the opening pressure of the explosion-proof structure, the explosion-proof structure can be broken through to discharge the pressure in the power battery, thereby improving the safety performance of the power battery. The explosion-proof structure of the present application does not require any modification to other structures of the power battery. The first protective layer in the explosion-proof structure can be torn off and attached to the aluminum cover. There is no need to design and install redundant parts. The entire manufacturing process is simple, low in cost, and low in failure rate. Moreover, the explosion-proof structure does not occupy the internal space of the power battery, which is beneficial to improving the volume utilization of the battery cell and the energy density of the battery pack.

[0017] Other features and advantages of the present application will become apparent from the following detailed description of exemplary embodiments of the present application with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the application and, together with the description, serve to explain the principles of the application.

[0019] Figure 1 1 is a schematic structural diagram of a battery explosion-proof structure according to the present invention;

[0020] Figure 2 is a cross-sectional view of the battery explosion-proof structure of the present invention;

[0021] Figure 3 This is a schematic diagram of attaching the explosion-proof structure of the present invention to the aluminum cover;

[0022] Figure 4 It is a cross-sectional view of the explosion-proof structure of the present invention after being attached to the aluminum cover plate.

[0023] Reference numerals:

[0024] Explosion-proof structure 10; first protective layer 11; metal layer 12; second protective layer 13;

[0025] Aluminum cover plate 20; Insulation spacer 21;

[0026] Pole 30. DETAILED DESCRIPTION

[0027] Various exemplary embodiments of the present application will now be described in detail with reference to the accompanying drawings. It should be noted that unless otherwise specifically stated, the relative arrangements of components and steps, numerical expressions and numerical values ​​set forth in these embodiments do not limit the scope of the present application.

[0028] The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the present disclosure, its application, or uses.

[0029] Technologies, methods, and equipment known to ordinary technicians in the relevant art may not be discussed in detail, but where appropriate, the technologies, methods, and equipment should be considered part of the specification.

[0030] In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not limiting. Therefore, other examples of the exemplary embodiments may have different values.

[0031] It should be noted that like reference numerals and letters refer to like items in the following figures, and therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0032] The following describes in detail the battery explosion-proof structure 10 according to an embodiment of the present invention with reference to the accompanying drawings.

[0033] like Figures 1 to 4 As shown, a battery explosion-proof structure 10 according to an embodiment of the present invention is used to be attached to a power battery. The explosion-proof structure 10 includes a first protective layer 11, a metal layer 12, and a second protective layer 13 stacked in sequence.

[0034] Specifically, the first protective layer 11 and the second protective layer 13 are made of polyester material, and the first protective layer 11 is removable on the metal layer 12. The metal layer 12 is a lithium-containing metal material and is used to contact and adhere to the aluminum cover plate 20 of the power battery. The metal layer 12 and the aluminum cover plate 20 form a diffusion effect, thereby reducing the structural strength at the point where the aluminum cover plate 20 and the metal layer 12 are attached, and forming a blast zone. When the gas pressure in the power battery reaches the opening pressure of the explosion-proof structure 10, the gas in the power battery breaks through the explosion-proof structure 10 to discharge the gas within the power battery.

[0035] In other words, the battery explosion-proof structure 10 according to the embodiment of the present invention is mainly used to be attached to a power battery as an explosion-proof structure 10 on the power battery. Figure 1 and Figure 2 The explosion-proof structure 10 is mainly composed of a first protective layer 11, a metal layer 12 and a second protective layer 13. The first protective layer 11, the metal layer 12 and the second protective layer 13 are stacked in sequence to form an explosion-proof patch. The first protective layer 11 and the second protective layer 13 can be made of polyester material. The first protective layer 11 and the second protective layer 13 can protect the metal layer 12 and appropriately improve the strength of the battery explosion-proof structure 10. Figure 3 and Figure 4As shown, the first protective layer 11 on the metal layer 12 can be torn off. During the installation of the explosion-proof structure 10 with the power battery, the first protective layer 11 is torn off, and the metal layer 12 of the explosion-proof structure 10 is facing the aluminum cover 20 of the power battery. The metal layer 12 is attached to the aluminum cover 20 to achieve the installation and fixation of the explosion-proof structure 10 on the power battery.

[0036] In the present application, before the explosion-proof structure 10 is installed, there is no need to make any improvements to the structure in the power battery (for example, hollowing out or etching the cover structure), which reduces the difficulty of designing the battery cell. The prior design of the explosion-proof structure 10 can be cancelled. After the battery cell is produced, the explosion-proof structure 10 can be bonded to the aluminum cover 20.

[0037] The metal layer 12 can be made of a lithium-containing metal material. The metal layer 12 is used to contact the aluminum cover plate 20 of the power battery. The metal layer 12 is attached to the aluminum cover plate 20 and can form a diffusion effect with the aluminum cover plate 20. The lithium ions in the metal layer 12 will diffuse into the aluminum cover plate 20. Through the diffusion cold welding process between the metal layer 12 and the aluminum cover plate 20, the structural strength of the location where the aluminum cover plate 20 and the metal layer 12 are attached can be reduced, making it a weak area of ​​the entire power battery structure, that is, the explosion area. When the gas pressure in the power battery reaches the opening pressure of the explosion-proof structure 10, the gas in the power battery breaks through the explosion-proof structure 10, and the power battery tears and deflates in the explosion area, thereby achieving the discharge of gas in the power battery and improving the safety of the battery cell and the entire power battery.

[0038] In the present application, the metal layer 12 and the aluminum cover plate 20 are alloy diffusions, which can ensure that the structural strength of the aluminum cover plate 20 does not decrease too much. At the same time, it can also ensure that the interface between the metal layer 12 and the aluminum cover plate 20 is uniform, thereby improving the overall consistency of the blasting area and reducing the deviation of the opening pressure of the explosion-proof structure 10.

[0039] The explosion-proof structure 10 of this application features a simple overall design, low cost, and a low failure rate. Once installed during battery cell production, the explosion-proof structure 10 effectively reduces the risk of electrolyte corrosion in the blast zone. Furthermore, by being attached to the outer wall of the aluminum cover plate 20, the explosion-proof structure 10 does not occupy internal battery space, thereby improving the volume utilization of the battery cells and the energy density of the battery pack.

[0040] Of course, the principle of the diffusion effect (alloy diffusion) is understandable to those skilled in the art and will not be described in detail in this application.

[0041] Thus, the explosion-proof structure 10 according to the embodiment of the present invention is a patch structure composed of a first protective layer 11, a metal layer 12, and a second protective layer 13 stacked together. The first protective layer 11 can be torn off, and the metal layer 12 is made of a lithium-containing metal material. By attaching the metal layer 12 to the aluminum cover plate 20 and forming a diffusion effect, the structural strength at the location where the aluminum cover plate 20 and the metal layer 12 are attached is reduced, so that a weak explosion area is formed at the patch location. When the gas pressure in the power battery reaches the opening pressure of the explosion-proof structure 10, it can break through the explosion-proof structure 10, discharge the pressure in the power battery, and improve the safety performance of the power battery. The explosion-proof structure 10 of the present application does not require any modification to other structures of the power battery. The first protective layer 11 in the explosion-proof structure 10 can be torn off and attached to the aluminum cover plate 20. There is no need to design and install unnecessary parts. The entire manufacturing process is simple, low cost, and low failure rate. In addition, the explosion-proof structure 10 does not occupy the internal space of the power battery, which is conducive to improving the volume utilization rate of the battery cell and the energy density of the battery pack.

[0042] According to one embodiment of the present invention, the metal layer 12 is a lithium-containing alloy, a mixture of at least two lithium-containing alloys, a passivated lithium metal material, or a mixture including a passivated lithium metal material.

[0043] That is, the metal layer 12 in the explosion-proof structure 10 (or explosion-proof patch) can be a lithium-containing alloy material or a mixture alloy of at least two lithium-containing alloys. The explosion-proof structure 10 can also be a passivated lithium metal material or a mixture including a passivated lithium metal material, such as a mixture formed by passivated lithium metal and aluminum oxide. The metal layer 12 formed by the lithium-containing metal material can achieve the diffusion of lithium ions in the metal layer 12 into the aluminum cover plate 20, thereby reducing the structural strength in the diffusion area of ​​the aluminum cover plate 20, forming an explosion-proof structure 10 with reduced pressure tolerance, which facilitates the blasting function of the explosion-proof structure 10.

[0044] In some specific embodiments of the present invention, the metal layer 12 can be formed by one or more of lithium aluminum alloy, lithium carbon alloy, lithium silicon alloy, lithium germanium alloy, lithium tin alloy, lithium gallium alloy, lithium indium alloy, lithium bismuth alloy, lithium calcium alloy, lithium magnesium alloy and lithium antimony alloy. The metal layer 12 formed by the lithium-containing metal material can realize the diffusion of lithium ions in the metal layer 12 into the aluminum cover plate 20, thereby reducing the structural strength in the diffusion area of ​​the aluminum cover plate 20 in turn, forming an explosion-proof structure 10 with reduced pressure tolerance, which is convenient for realizing the blasting function of the explosion-proof structure 10.

[0045] Of course, the metal layer 12 can also include a ternary alloy or a ternary alloy of the first main group elements, the second main group elements, the third main group elements, the transition metal elements and the rare earth metal elements with lithium elements respectively. The metal layer 12 formed by the lithium-containing metal material can realize the diffusion of lithium ions in the metal layer 12 into the aluminum cover plate 20, thereby reducing the structural strength in the diffusion area of ​​the aluminum cover plate 20 in turn, forming an explosion-proof structure 10 with reduced pressure tolerance, which is convenient for realizing the blasting function of the explosion-proof structure 10.

[0046] In the present application, any lithium-containing metal, alloy or mixed metal material that can diffuse lithium ions into the aluminum cover plate 20 should fall within the protection scope of the present application and will not be described in detail in the present application.

[0047] In some specific embodiments of the present invention, the thickness of the explosion-proof structure 10 is 50 μm-500 μm, wherein the thickness of the metal layer 12 is 15 μm-450 μm. The opening pressure of the explosion-proof structure 10 is 0.42 MPa-1.2 MPa. The patch area of ​​the explosion-proof structure 10 is 10 mm 2 -3000mm 2 .

[0048] In other words, in the present application, the explosion-proof valve structure is a three-layer laminate structure, and the thickness of the explosion-proof structure 10 is approximately 50μm-500μm. Optionally, the thickness of the explosion-proof structure 10 can be approximately 100μm-200μm. Among them, the thickness of the metal layer 12 can be 15μm-450μm, which can meet the blasting requirements of the explosion-proof structure 10. The opening pressure of the explosion-proof structure 10 can be 0.42MPa-1.2MPa. The patch area of ​​the explosion-proof structure 10 can be 10mm 2 -3000mm 2 .

[0049] It should be noted that in this application, the thickness and patch area of ​​the explosion-proof structure 10 should correspond to the thickness of the power battery's aluminum cover 20. The opening pressure of the explosion-proof structure 10 should correspond to the capacity of the power battery cells and the structural strength of the aluminum cover 20.

[0050] The explosion-proof structure 10 can be of any shape, for example, a regular or irregular shape such as a circle or a Chinese character. This application does not impose any specific restrictions on the thickness, patch area, or shape of the explosion-proof structure 10. As long as the explosion-proof structure 10 is attached to the corresponding aluminum cover 20 of the power battery and can meet the explosion-proof requirements, the design should fall within the scope of protection of this application.

[0051] At the same time, in this application, there is no limitation on the specific shape of the explosion-proof structure 10 (explosion-proof patch). The explosion-proof structure 10 can be a regular or irregular shape such as an ellipse, a circle, or a square. At the same time, the explosion-proof structure 10 can also adopt a solid, hollow or discontinuous shape. Moreover, this application does not specifically limit the patch position of the explosion-proof structure 10 on the shell of the power battery. It can be on the aluminum cover plate 20 or on other positions of the shell that are convenient for exhausting gas when the explosion-proof device explodes. In this regard, as long as the shape, patch position and other designs that can meet the explosion-proof requirements of the explosion-proof structure 10 on the power battery, they should fall within the scope of protection of this application.

[0052] In a specific embodiment of the present application, the thickness of the aluminum cover plate 20 of the power battery can be 300 μm as an example. For a battery cell with a capacity of 100 Ah, the patch area of ​​the explosion-proof structure 10 can be 500 mm. 2 The metal layer 12 of the explosion-proof structure 10 can be made of lithium aluminum alloy (for example: Li 0.1 A1), the thickness of the metal layer 12 is 75 μm, and the opening pressure of the explosion-proof structure 10 is 0.6 MPa. When the gas pressure inside the power battery reaches 0.6 MPa, the gas can break through the explosion-proof structure 10, tearing it open and leaking gas, reducing the internal pressure of the power battery and improving the safety performance of the power battery.

[0053] In the present application, taking lithium aluminum alloy as an example, most alloys containing Li will experience phenomena such as decreased toughness and pulverization when the Li content is too high, making it difficult to form a plate. The present application can add about 0.02 molar ratio of Li to the aluminum shell to achieve the effect of reducing strength. Therefore, the Li content in the metal layer 12 used in the present application is preferably less than 0.2 and greater than 0.01. When the Li content in the metal layer 12 is greater than 0.01, the metal layer 12 can no longer be called a layer, and in this case the alloy will be oxidized by air. When the Li content in the metal layer 12 is less than 0.2, the Li content is insufficient and a good diffusion effect cannot be formed. Of course, if it is other materials, such as graphite, its content ratio to aluminum is basically equivalent to the molar ratio of lithium aluminum, and will not be described in detail in this application.

[0054] According to one embodiment of the present application, the first protective layer 11 and the second protective layer 13 are respectively adhesively connected to the metal layer 12, and the first protective layer 11 and the second protective layer 13 respectively include a polymer substrate and an adhesive layer adhered to the explosion-proof structure 10. That is, the first protective layer 11 can be connected to the metal layer 12 through an adhesive layer, and the second protective layer 13 can be connected to the metal layer 12 through an adhesive layer. When the explosion-proof structure 10 is in use, the first protective layer 11 can be torn off. The first protective layer 11 and the second protective layer 13 can respectively adopt polymer materials, and the polymer materials of the first protective layer 11 and the second protective layer 13 can be the same or different. The first protective layer 11 and the second protective layer 13 are respectively protective tapes. Among them, the first protective layer 11 includes a polymer substrate and an adhesive layer adhered to the explosion-proof structure 10. The second protective layer 13 also includes a polymer substrate and an adhesive layer adhered to the explosion-proof structure 10. In this application, the polymer substrate layer includes: polyethylene, polypropylene, polyvinyl chloride, polyamide, Teflon, polyethylene terephthalate, ethylene vinyl acetate copolymer, cloth base, paper base, various fibers, etc., and the adhesive layer includes: hot melt adhesive, acrylate, acrylic adhesive, natural rubber and synthetic rubber, etc.

[0055] In summary, the explosion-proof structure 10 according to an embodiment of the present invention is a patch structure composed of a first protective layer 11, a metal layer 12, and a second protective layer 13 stacked together. The first protective layer 11 can be torn off, and the metal layer 12 is made of a lithium-containing metal material. By attaching the metal layer 12 to the aluminum cover plate 20 and forming a diffusion effect, the structural strength of the aluminum cover plate 20 and the metal layer 12 at the attachment position is reduced, so that a weak blasting area is formed at the patch position. When the gas pressure in the power battery reaches the opening pressure of the explosion-proof structure 10, it can break through the explosion-proof structure 10, discharge the pressure in the power battery, and improve the safety performance of the power battery. The explosion-proof structure 10 of the present application does not require any modification to other structures of the power battery. The first protective layer 11 in the explosion-proof structure 10 can be torn off and attached to the aluminum cover plate 20. There is no need to design and install unnecessary parts. The entire manufacturing process is simple, low cost, and low failure rate. In addition, the explosion-proof structure 10 does not occupy the internal space of the power battery, which is conducive to improving the volume utilization rate of the battery cell and the energy density of the battery pack.

[0056] According to a second aspect of the present invention, a power battery is provided. The power battery includes a housing, a battery cell, and a battery explosion-proof structure 10 .

[0057] Specifically, a housing is defined within the shell, and the shell has an aluminum cover 20 to cover the housing. The battery cell is located within the housing. In the battery explosion-proof structure 10 in the above embodiment, after the first protective layer 11 is removed from the explosion-proof structure 10, the metal layer 12 faces the aluminum cover 20 and is attached to the aluminum cover 20. The metal layer 12 and the aluminum cover 20 form a diffusion effect to reduce the structural strength at the location where the aluminum cover 20 and the metal layer 12 are attached, and form a blasting area. When the gas pressure in the power battery reaches the pressure threshold of the blasting area, the gas in the power battery breaks through the blasting area to discharge the gas in the power battery.

[0058] That is to say, if Figures 1 to 4 As shown, the power battery according to the embodiment of the present invention mainly consists of a shell, a battery cell and a battery explosion-proof structure 10. Among them, a receiving cavity is set in the shell, and the shell has an aluminum cover 20. The aluminum cover 20 can be used to cover the receiving cavity. The aluminum cover 20 can be provided with a pole 30, an insulating spacer 21 and other structures. The battery cell is installed in the receiving cavity. Figure 3 and Figure 4 When the battery explosion-proof structure 10 is attached to the aluminum cover plate 20, the first protective layer 11 can be torn off first, and then the metal layer 12 is facing the aluminum cover plate 20 and attached to the aluminum cover plate 20 to achieve the installation and fixation of the explosion-proof structure 10 on the power battery. The metal layer 12 is attached to the aluminum cover plate 20 and can form a diffusion effect with the aluminum cover plate 20. The lithium ions in the metal layer 12 will diffuse into the aluminum cover plate 20. Through the diffusion cold welding process of the metal layer 12 and the aluminum cover plate 20, the structural strength of the position where the aluminum cover plate 20 and the metal layer 12 are attached can be reduced, making it a weak area of ​​the entire power battery structure, that is, the explosion area. When the gas pressure in the power battery reaches the opening pressure of the explosion area, the gas in the power battery breaks through the explosion-proof structure 10, and the power battery is torn and deflated at the explosion area, thereby achieving the discharge of gas in the power battery and improving the safety of the battery cell and the entire power battery.

[0059] In the present application, before the explosion-proof structure 10 is installed, there is no need to make any improvements to the structure in the power battery (for example, hollowing out or etching the cover structure), which reduces the difficulty of designing the battery cell. The prior design of the explosion-proof structure 10 can be cancelled. After the battery cell is produced, the explosion-proof structure 10 can be bonded to the aluminum cover 20.

[0060] The metal layer 12 can be made of a lithium-containing metal material. The metal layer 12 is used to contact the aluminum cover plate 20 of the power battery. The metal layer 12 is attached to the aluminum cover plate 20 and can form a diffusion effect with the aluminum cover plate 20. The lithium ions in the metal layer 12 will diffuse into the aluminum cover plate 20. Through the diffusion cold welding process between the metal layer 12 and the aluminum cover plate 20, the structural strength of the location where the aluminum cover plate 20 and the metal layer 12 are attached can be reduced, making it a weak area of ​​the entire power battery structure, that is, the explosion area. When the gas pressure in the power battery reaches the opening pressure of the explosion-proof structure 10, the gas in the power battery breaks through the explosion-proof structure 10, and the power battery tears and deflates in the explosion area, thereby achieving the discharge of gas in the power battery and improving the safety of the battery cell and the entire power battery.

[0061] In the present application, the metal layer 12 and the aluminum cover plate 20 are alloy diffusions, which can ensure that the structural strength of the aluminum cover plate 20 does not decrease too much. At the same time, it can also ensure that the interface between the metal layer 12 and the aluminum cover plate 20 is uniform, thereby improving the overall consistency of the blasting area and reducing the deviation of the opening pressure of the explosion-proof structure 10.

[0062] The explosion-proof structure 10 of this application features a simple overall design, low cost, and a low failure rate. Once installed during battery cell production, the explosion-proof structure 10 effectively reduces the risk of electrolyte corrosion in the blast zone. Furthermore, by being attached to the outer wall of the aluminum cover plate 20, the explosion-proof structure 10 does not occupy internal battery space, thereby improving the volume utilization of the battery cells and the energy density of the battery pack.

[0063] In some specific embodiments of the present invention, the ratio of the thickness of the aluminum cover plate 20 to the thickness of the metal layer 12 is 0.1-100. The pressure threshold of the blasting area is 0.42 MPa-1.2 MPa, and the time for the metal layer 12 and the aluminum cover plate 20 to form a diffusion effect is 30 minutes to 72 hours. Optionally, the time for the metal layer 12 and the aluminum cover plate 20 to form a diffusion effect is 12 hours.

[0064] Taking the aluminum cover 20 of the power battery as an example, which has a thickness of 300 μm, for a battery cell with a capacity of 100 Ah, the patch area of ​​the explosion-proof structure 10 can be 500 mm 2 The metal layer 12 of the explosion-proof structure 10 can be made of lithium aluminum alloy (for example: Li 0.1 A1), the thickness of the metal layer 12 is 75 μm, and the opening pressure of the explosion-proof structure 10 is 0.6 MPa. When the gas pressure inside the power battery reaches 0.6 MPa, the gas can break through the explosion-proof structure 10, tearing it open and leaking gas, reducing the internal pressure of the power battery and improving the safety performance of the power battery.

[0065] In the present application, during the manufacturing process of the explosion-proof structure 10, it is only necessary to tear off the lower protective layer (first protective layer 11) of the explosion-proof patch and attach the middle alloy material (metal layer 12) to the aluminum cover plate 20 of the battery cell with the battery cell facing the battery cell. After a certain period of element diffusion and cold welding, the explosion-proof structure 10 with reduced pressure tolerance can be formed. The opening pressure of the explosion-proof structure 10 can be designed and controlled. Because the explosion-proof structure 10 is obtained by element diffusion and cold welding, the structure is uniform and the opening pressure deviation of the explosion-proof valve is small.

[0066] In this application, there is no limitation on the specific shape, thickness, etc. of the explosion-proof structure 10 (explosion-proof patch). The explosion-proof structure 10 can be a regular or irregular shape such as an ellipse, a circle, or a square. At the same time, the explosion-proof structure 10 can also adopt a solid, hollow, or discontinuous shape. Moreover, this application does not specifically limit the patch position and patch method of the explosion-proof structure 10 on the shell of the power battery. It can be on the aluminum cover plate 20 or on other locations of the shell that are convenient for exhausting gas when the explosion-proof device explodes. In this regard, as long as the shape, patch position, and other designs that can meet the explosion-proof requirements of the explosion-proof structure 10 on the power battery are designed, they should fall within the scope of protection of this application.

[0067] In the present application, during the attachment process of the explosion-proof structure 10 to the aluminum cover plate 20, the location of the aluminum cover plate 20 to be attached can be cleaned and polished first, so as to facilitate the rapid attachment of the explosion-proof structure 10 to the aluminum cover plate 20, thereby improving the tightness of the attachment of the explosion-proof structure 10 to the aluminum cover plate 20. At the same time, after the explosion-proof structure 10 is attached to the aluminum cover plate 20, a certain pressure can be applied to the explosion-proof structure 10 and maintained for a certain period of time, or a certain temperature (for example, 45°C) can be maintained to quickly form the explosion-proof structure 10.

[0068] In summary, according to the power battery of the embodiment of the present invention, the explosion-proof structure 10 can be attached to the aluminum cover after the first protective layer 11 is torn off, and the metal layer 12 composed of lithium-containing metal material is attached to the aluminum cover plate 20 to form a diffusion effect, thereby reducing the structural strength of the aluminum cover plate 20 and the metal layer 12 at the attachment position, so that a weak blasting area is formed at the patch position. When the gas pressure in the power battery reaches the opening pressure of the explosion-proof structure 10, the explosion-proof structure 10 can be broken through, the pressure in the power battery can be discharged, and the safety performance of the power battery can be improved. The explosion-proof structure 10 of the present application does not require any modification to other structures of the power battery. The first protective layer 11 in the explosion-proof structure 10 can be torn off and attached to the aluminum cover plate 20. There is no need to design and install unnecessary parts. The entire manufacturing process is simple, low cost, and low failure rate. In addition, the explosion-proof structure 10 does not occupy the internal space of the power battery, which is conducive to improving the volume utilization rate of the battery cell and the energy density of the battery pack.

[0069] Of course, other structures of the power battery and the working principles of the power battery are understandable and achievable, and will not be described in detail in this application.

[0070] Although some specific embodiments of the present application have been described in detail by way of examples, it should be understood by those skilled in the art that the above examples are for illustration only and are not intended to limit the scope of the present application. It should be understood by those skilled in the art that the above embodiments may be modified without departing from the scope and spirit of the present application. The scope of the present application is defined by the appended claims.

Claims

1. A battery explosion-proof structure, characterized in that: The explosion-proof structure is used to be attached to the power battery, and the explosion-proof structure includes a first protective layer, a metal layer, and a second protective layer stacked in sequence; wherein, The first protective layer and the second protective layer are made of polyester material, and the first protective layer can be torn off on the metal layer; The metal layer is a lithium-containing metal material. The metal layer is used to contact and adhere to the aluminum cover of the power battery, and form a diffusion effect with the aluminum cover to reduce the structural strength of the aluminum cover and the metal layer at the attachment position, and form an explosion area; when the gas pressure in the power battery reaches the opening pressure of the explosion-proof structure, the gas in the power battery breaks through the explosion-proof structure to discharge the gas in the power battery.

2. The battery explosion-proof structure according to claim 1, characterized in that: The metal layer is a lithium-containing alloy, a mixture of at least two lithium-containing alloys, a passivated lithium metal material, or a mixture including a passivated lithium metal material.

3. The battery explosion-proof structure according to claim 2, characterized in that: The metal layer includes one or more of lithium aluminum alloy, lithium carbon alloy, lithium silicon alloy, lithium germanium alloy, lithium tin alloy, lithium gallium alloy, lithium indium alloy, lithium bismuth alloy, lithium calcium alloy, lithium magnesium alloy and lithium antimony alloy.

4. The battery explosion-proof structure according to claim 2, characterized in that: The metal layer includes a ternary alloy or a ternary alloy of more than one element consisting of a first main group element, a second main group element, a third main group element, a transition metal element, a rare earth metal element and lithium element.

5. The battery explosion-proof structure according to claim 1, characterized in that: The explosion-proof structure has a thickness of 50 μm-500 μm, wherein the metal layer has a thickness of 15 μm-450 μm.

6. The battery explosion-proof structure according to claim 1, characterized in that: The opening pressure of the explosion-proof structure is 0.2MPa-1.2MPa.

7. The battery explosion-proof structure according to claim 1, characterized in that: The patch area of ​​the explosion-proof structure is 10mm 2 -3000mm 2 .

8. The battery explosion-proof structure according to claim 1, characterized in that: The first protective layer and the second protective layer are respectively adhesively connected to the metal layer, and the first protective layer and the second protective layer respectively include a polymer substrate adhered to the explosion-proof structure and an adhesive layer.

9. A power battery, characterized in that: include: A housing defines a receiving cavity therein, and the housing has an aluminum cover plate for covering the receiving cavity; A battery cell, the battery cell being located in the accommodating cavity; The battery explosion-proof structure according to any one of claims 1 to 8, wherein after the first protective layer is removed from the explosion-proof structure, the metal layer faces the aluminum cover plate and is attached to the aluminum cover plate, and the metal layer and the aluminum cover plate form a diffusion effect to reduce the structural strength at the location where the aluminum cover plate and the metal layer are attached, thereby forming an explosion area; When the gas pressure in the power battery reaches the pressure threshold of the explosion area, the gas in the power battery breaks through the explosion area to discharge the gas in the power battery.

10. The power battery according to claim 9, characterized in that: The ratio of the thickness of the aluminum cover plate to the thickness of the metal layer is 0.1-100.

11. The power battery according to claim 9, characterized in that: The pressure threshold of the blasting area is 0.42MPa-1.2MPa, and the time for the metal layer and the aluminum cover plate to form a diffusion effect is 30min-72h.

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