A battery pack and electrical device

Abstract

This invention provides a battery pack and electrical device, relating to the field of battery technology. Specifically, it includes a battery pack, a casing, and a safety protection component; the safety protection component is disposed on the outside of the battery pack or between the battery cells within the battery pack; the safety protection component includes a nano-protective shell and a molding compound, wherein the nano-protective shell has a hollow structure and a vacuum interior, and its surface is provided with an air inlet and an air outlet. By adopting the above structural design, this invention further reduces the thermal conductivity of the nano-protective shell, which originally has a low thermal conductivity, meeting the requirements for thermal insulation materials, thus integrating thermal insulation materials and safety protection materials, achieving the integration of two distinct functions; while improving the integration of the overall pack design, it reduces the overall pack weight, thereby reducing the overall pack development costs and material costs.

Description

Technical Field

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

[0002] With the rapid popularization of electric vehicles, consumers and automakers are paying increasing attention to battery safety. Power batteries are not only the main power source and core component of electric vehicles, but also a major technological barrier to their rapid development. Lithium-ion batteries, with their advantages of high energy density, long cycle life, and environmental friendliness, are widely used in mobile phones, electric vehicles, power banks, and many other fields.

[0003] Lithium-ion batteries present a range of safety challenges due to factors such as structural design, material selection, manufacturing processes, performance, and external environment. For example, the inherent thermal risks of lithium-ion batteries stem from their materials and structural characteristics. During long-term charge-discharge cycles, factors like lithium dendrite formation and mechanical abuse can trigger thermal runaway, producing large amounts of toxic or highly flammable gases, leading to subsequent violent fires or explosions. Furthermore, batteries generate heat during charging and discharging, influenced by factors such as charge / discharge rate and operating temperature, causing the battery temperature to rise. If this heat cannot dissipate promptly, thermal runaway can occur, potentially leading to combustion and explosions. Additionally, collisions or crushing of batteries or battery packs in traffic accidents can damage the internal structure, causing thermal runaway. The activation of internal side reactions can also trigger thermal runaway. These are the root causes of fires in new energy vehicles. To prevent thermal runaway of the battery pack from causing thermal diffusion and potentially leading to a fire or explosion that poses a significant threat to passenger safety, current manufacturing processes incorporate battery safety structures within the battery pack to suppress or prevent thermal diffusion. These safety structures must possess safety characteristics such as heat insulation, electrical insulation, and fire retardancy.

[0004] It is also worth noting that, in addition to the aforementioned performance requirements of heat insulation and flame retardancy, in order to reduce the impact of temperature on battery pack performance in low-temperature environments, it is also necessary to set up some thermal insulation structures inside the battery pack. Currently, a common measure is to arrange thermal insulation layers in the battery pack. This is mainly because when lithium-ion batteries are in a low-temperature state, their usable capacity decreases and their charging and discharging power is limited; the lower the ambient temperature, the lower the activity of the active materials in the battery, the higher the internal resistance and viscosity of the electrolyte, the more difficult ion diffusion becomes, and the slower the diffusion rate of lithium ions in the electrodes at low temperatures, making it difficult for them to insert and easy for them to extract, thus causing a rapid drop in capacity; therefore, it can be seen that low-temperature use will have a significant impact on battery life, and thermal insulation structures are needed to ensure low-temperature electrical performance.

[0005] In summary, besides having low thermal conductivity, the insulation materials used in battery packs, due to their placement within the pack, also need to possess characteristics such as flame retardancy, insulation, flexibility, high-temperature resistance, and lightweight to meet requirements for electrochemical and safety performance. However, a typical battery pack requires the simultaneous placement of safety protection and insulation materials, which makes the internal structure overly complex. This overly complex structural design also affects the internal space arrangement, reducing the space ratio of the battery cells and thus lowering battery performance, while also increasing the overall design cost of the pack.

[0006] In view of this, the present invention is hereby proposed. Summary of the Invention

[0007] The primary objective of this invention is to provide a battery pack that addresses the technical shortcomings of existing battery structures, such as the complexity of the internal structure of the battery pack due to safety structural components for preventing thermal runaway and thermal insulation components for ensuring low-temperature performance, which affect the proportion of cell space and increase the design cost of the battery pack.

[0008] The second objective of this invention is to provide an electrical device that effectively simplifies the battery pack structure while effectively ensuring the device's high and low temperature performance and safety performance.

[0009] In order to achieve the above-mentioned objectives of the present invention, the following technical solution is adopted:

[0010] A battery pack includes a battery pack, a housing, and safety protection components;

[0011] The safety protection component is disposed on the outside of the battery pack, or the safety protection component is disposed between the cells in the battery pack;

[0012] The safety protection component includes a nano-protective shell and a plastic seal layer; the plastic seal layer is encapsulated on the outside of the nano-protective shell; the nano-protective shell has a hollow structure and the inside of the nano-protective shell is in a vacuum state; the nano-protective shell is provided with an air inlet and an air outlet.

[0013] An electrical device includes the aforementioned battery pack.

[0014] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0015] This invention provides a thermal insulation material with excellent heat insulation and flame retardant properties by vacuuming a nano-protective shell and then encapsulating it with a plastic sealing layer. It also exhibits good safety protection and low-temperature resistance. The safety protection component based on this invention integrates the thermal insulation and heat protection designs within the battery pack, improving the overall pack design's integration and avoiding spatial interference problems caused by complex structural designs. Simultaneously, the reduced structural design lowers the overall pack weight and reduces development costs and material expenses. Furthermore, its combined thermal insulation and heat protection functions indirectly increase the cell space ratio, significantly improving the overall electrochemical performance of the pack. Attached Figure Description

[0016] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0017] Figure 1 A schematic diagram of the battery pack structure of the present invention is provided. Detailed Implementation

[0018] The technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings and specific embodiments. However, those skilled in the art will understand that the embodiments described below are some embodiments of the present invention, but not all embodiments, and are only used to illustrate the present invention, and should not be regarded as limiting the scope of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall be followed. Where the manufacturers of reagents or instruments are not specified, they are all conventional products that can be purchased commercially.

[0019] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0020] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" 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 mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0021] A first aspect of the present invention is to provide a battery pack.

[0022] The battery pack includes at least a battery assembly, a casing, and safety protection components. It is understood that the battery assembly is a battery power system composed of multiple cells connected in series, parallel, or a hybrid configuration. In some optional embodiments, the battery assembly consists of a single cell, such as a test battery or a button cell; in this case, the battery assembly can be equivalent to the cell involved in this invention. This invention does not impose any limitations on the composition or structural relationship of the battery assembly. It is also understood that the casing is the outermost structural element of the battery pack, serving to support the overall mechanical structure and protect against external damage; this invention does not impose any limitations on the shape, material, or structure of the casing.

[0023] The location of the safety protection component described in this invention should be determined in conjunction with the battery pack; optionally, the safety protection component is located on the outside of the battery pack, or the safety protection component is located between the cells in the battery pack.

[0024] In a preferred embodiment, the safety protection component is disposed on the outside of the battery pack, meaning that the safety protection component is designed to partially or completely cover the outside of the battery pack. Since this invention does not limit the structural appearance of the safety protection component and the battery pack, taking a cuboid battery pack as an example: the safety protection component can be disposed on the top or bottom surface of the battery pack (here, the top and bottom surfaces are defined as the planes adjacent to the outer casing of the battery pack), or the safety protection component can be disposed on any plane of the battery pack with a relatively large surface area, or the safety protection component can cover several adjacent planes of the battery pack.

[0025] The safety protection component of this invention comprises at least a nano-protective shell and a plastic sealing layer. The nano-protective shell is made of a material that combines safety protection and thermal insulation properties, serving to achieve corresponding thermal protection and insulation effects. The plastic sealing layer encapsulates the exterior of the nano-protective shell. The nano-protective shell has a hollow structure, and its interior is a vacuum. The nano-protective shell is provided with an air inlet and an air outlet.

[0026] As a preferred embodiment, the assembly process of the safety protection component includes the following steps: first, the interior of the nano-protective shell is evacuated to a vacuum state, then the nano-protective shell is placed into a plastic sealing bag, and the air inside the plastic sealing bag is further extracted to obtain the plastic sealing layer attached to the surface of the nano-protective shell.

[0027] In a preferred embodiment, the material of the molding layer includes polyethylene terephthalate (PET), and the molecular weight of the PET is 200 to 30,000, including but not limited to any one or any two of the following: 200, 250, 1,000, 5,000, 10,000, 15,000, 20,000, 25,000, and 30,000.

[0028] As a preferred embodiment, the nano-protective shell can be understood as a closed shell made of nanomaterials, with a vacuum inside; the nano-protective shell can be obtained by building a nanosheet and then sealing it, or it can be directly prepared by an integrated nanosheet process.

[0029] In a more preferred embodiment, the nanomaterial includes nanoscale silica, a light-shielding functional component, and a reinforcing fiber component.

[0030] In some optional embodiments, the particle size of the nanoscale silica is 0.1 nm to 100 nm, including but not limited to any one or any two values ​​of 0.1, 0.5, 1, 5, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100 (nm).

[0031] In some alternative embodiments, the light-shielding functional component includes at least one of metal oxides, such as ferric oxide, manganese dioxide, cobalt oxide, copper oxide, and other reflective spinel dopants.

[0032] In some optional embodiments, the reinforcing fiber component includes inorganic fibers or organic fibers. Inorganic fibers include, but are not limited to, carbon fibers, boron fibers, glass fibers, etc., while organic fibers include, but are not limited to, polyester fibers, nylon fibers, polypropylene fibers, polyimide fibers, or certain natural fibers.

[0033] As a further preferred embodiment, the nanomaterial comprises the following components by weight: 30-100 parts of nano-sized silica, 0.1-30 parts of a light-shielding functional component, and 0.01-10 parts of a reinforcing fiber component. Optionally, the nanomaterial may also include other functional components, such as components for improving the hardness, toughness, and melting point of the sheet material, which can be formulated according to actual needs by those skilled in the art.

[0034] As a further preferred embodiment, the preparation method of the nanomaterial includes: fully mixing raw material components including nano-sized silica, light-shielding functional components and reinforcing fiber components, and then die-casting to obtain nano-plates or integrated shell materials.

[0035] In a preferred embodiment, the thermal conductivity of the safety protection component is ≤0.04W / (m·K).

[0036] In a more preferred embodiment, the thermal conductivity of the nano-protective shell is ≤0.04W / (m·K); the thermal conductivity of the plastic seal layer is ≤0.004W / (m·K).

[0037] Understandably, thermal conductivity refers to the coefficient of performance of a material with a thickness of 1m and a temperature difference of 1K between its two surfaces under steady-state heat transfer conditions, which allows for the efficient transfer of heat through the material over 1 hour. 2 Heat transfer over area. Because the nanomaterials used in the aforementioned nano-protective shell already have a very low thermal conductivity, vacuuming effectively prevents heat transfer caused by air convection, thus further reducing the thermal conductivity significantly. It serves as both a safety protection material and a high-performance insulation material. Simultaneously, due to the material's barrier effect, heat is contained on one side, preventing significant heat loss and providing excellent thermal insulation.

[0038] Furthermore, after being vacuumed, the nano-protective shell, being a safety material itself, can also meet some characteristics of battery safety protection, such as insulation, heat insulation, high temperature resistance, and fire resistance. It effectively ensures that in the event of thermal runaway of the battery cell, when the battery cell generates a large amount of heat and smoke due to violent reaction, it can effectively block heat and play an insulating role.

[0039] Regarding the air inlet and outlet of the nano-protective shell described in this invention, although an "air port" structure exists, the internal vacuum of the nano-protective shell under normal conditions can be maintained by the plastic sealing layer disposed on the outside of the nano-protective shell. The "normal conditions" referred to here mean the state under which no safety hazards occur or thermal runaway of the battery cell during battery operation, standby, or charging / discharging scenarios. In this state, both the air inlet and outlet are sealed by the plastic sealing layer to maintain the internal vacuum state of the nano-protective shell.

[0040] Correspondingly, when thermal runaway occurs in the battery cell, the cell valve will generate a large amount of high-temperature gas. A dedicated exhaust channel must be set up to discharge these gases from the casing in a timely manner. That is, the high-temperature gas breaks through the plastic seal layer corresponding to the air inlet based on the air pressure effect, enters the vacuum cavity of the nano-protective shell, and when the internal pressure value accumulates to a certain level, it breaks through the plastic seal layer corresponding to the air outlet and is discharged through the air outlet.

[0041] In a preferred embodiment, the air inlet is located near the explosion-proof valve of the battery cell, and the air outlet is located near the explosion-proof valve of the housing.

[0042] In a preferred embodiment, when the number of battery cells in the battery pack is greater than 1, the safety protection component includes several air inlets corresponding to the explosion-proof valves of the battery cells; in some other embodiments, the number of the safety protection component is also greater than 1 to meet the venting requirements of several battery cells; in some other embodiments, not every battery cell's venting valve has a corresponding air inlet.

[0043] like Figure 1 The diagram shows a schematic of a battery pack structure.

[0044] exist Figure 1 The battery pack consists of two cells. A nano-protective shell in the safety protection component covers three sides of the two cells. The nano-protective shell itself forms a hollow structure with a vacuum exhaust channel inside. When a cell experiences thermal runaway, two independent air inlets can supply the gas generated by the thermal runaway into the exhaust channel and discharge it from the air outlet adjacent to the explosion-proof valve on the outer shell of the battery pack. This achieves electrothermal separation after thermal runaway of the entire pack and improves the safety performance of the battery pack design.

[0045] In a preferred embodiment, a protective film is provided inside the nano-protective shell at a position corresponding to the air inlet.

[0046] It is understood that, regarding the molding compound layer described in this invention, when thermal runaway occurs, at the air inlet corresponding to the thermal runaway, the molding compound layer and the protective film will be immediately broken due to the impact of instantaneous high-temperature and high-pressure gas. Simultaneously, because the temperature and pressure of the gas during recirculation are significantly lower than when it first enters the nano-protective shell, it will not blow open the molding compound layer and the protective film above other cells, thus avoiding impact on other cells. In the safety protection component with more than one air inlet, to ensure that the gas entering the nano-protective shell is discharged through the air outlet (rather than through other air inlets where thermal runaway has not occurred), the protective film is added at the air inlet to ensure that the accumulated airflow is discharged through the air outlet, which is most affected by the pressure difference and has the weakest protection.

[0047] In a more preferred embodiment, the material of the protective film includes, but is not limited to, polyimide (PI), polyamide (PA), etc.

[0048] In summary, the working state of the safety protection components in the battery pack of the present invention is analyzed as follows:

[0049] First, when the ambient temperature of the package is normal, no thermal runaway occurs in the battery cells, and the entire package works normally; the overall package design can meet the power performance requirements of the entire package.

[0050] Second, when the ambient temperature of the package is normal, but the battery cell experiences thermal runaway, the entire package is partially or completely de-energized. At the same time, the safety protection components are used to promptly vent the gas, expelling the high-temperature and high-pressure gas outside the package, thus meeting the design requirements and national standards that prevent the entire package from catching fire or exploding.

[0051] Third, when the battery pack is in a low-temperature environment, the vacuum insulation structure of the safety protection component can store the heat inside the battery pack, keeping the temperature of the battery cell within a suitable temperature range. This can improve the charging speed of the battery cell and fully utilize its discharge capacity, thereby enhancing the battery life of the device.

[0052] A second aspect of the present invention is to provide an electrical appliance.

[0053] The electrical equipment includes the battery pack. It is understood that the electrical equipment can be any device or apparatus that relies on electrical energy to work or operate, including but not limited to new energy vehicles, building electrical equipment, industrial electrical appliances, household and agricultural electrical appliances, etc.; when the battery pack is included, any electrical equipment equipped with the battery pack can be considered an embodiment of the present invention. In some optional embodiments, the electrical equipment may further include power source components other than the battery pack.

[0054] Although the present invention has been illustrated and described with specific embodiments, it should be understood that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; those skilled in the art should understand that modifications can be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein, without departing from the spirit and scope of the present invention; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention; therefore, this means that all such substitutions and modifications that fall within the scope of the present invention are included in the appended claims.

Claims

1. A battery pack, characterized in that, The battery pack includes a battery pack, a housing, and safety protection components; The safety protection component is disposed on the outside of the battery pack, or the safety protection component is disposed between the cells in the battery pack; The safety protection component includes a nano-protective shell and a plastic seal layer; the plastic seal layer is encapsulated on the outside of the nano-protective shell; the nano-protective shell has a hollow structure and the inside of the nano-protective shell is in a vacuum state; the nano-protective shell is provided with an air inlet and an air outlet.

2. The battery pack according to claim 1, characterized in that, The material of the nano-protective shell includes nanomaterials; wherein, the nanomaterials include nano-sized silica, light-shielding functional components, and reinforcing fiber components.

3. The battery pack according to claim 2, characterized in that, The nanomaterial comprises the following components by weight: 30-100 parts of nano-sized silica, 0.1-30 parts of light-shielding functional component, and 0.01-10 parts of reinforcing fiber component.

4. The battery pack according to claim 2, characterized in that, The light-shielding functional component includes at least one of ferric oxide, manganese dioxide, cobalt oxide, or copper oxide.

5. The battery pack according to claim 1, characterized in that, The molding compound is made of polyethylene terephthalate; The molecular weight of the polyethylene terephthalate is 200-30000.

6. The battery pack according to claim 1, characterized in that, The assembly of the safety protection component includes the following steps: First, the interior of the nano-protective shell is evacuated to a vacuum state. Then, the nano-protective shell is placed into a plastic seal bag, and the air inside the plastic seal bag is removed to obtain the plastic seal layer attached to the surface of the nano-protective shell.

7. The battery pack according to claim 1, characterized in that, The thermal conductivity of the safety protection component is ≤0.04W / (m·K).

8. The battery pack according to claim 1, characterized in that, The air inlet is located near the explosion-proof valve of the battery cell, and the air outlet is located near the explosion-proof valve of the outer casing.

9. The battery pack according to claim 8, characterized in that, When the number of cells in the battery pack is greater than 1, the safety protection component includes a plurality of air inlets corresponding to the explosion-proof valves of the cells.

10. The battery pack according to claim 1, characterized in that, A protective film is provided inside the nano-protective shell at a position corresponding to the air inlet.

11. An electrical appliance, characterized in that, The electrical equipment includes a battery pack as described in any one of claims 1 to 10.

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