Battery pack and electric equipment

Abstract

The invention provides a battery pack and electric equipment, and relates to the technical field of batteries. Specifically, the battery pack comprises a battery pack, a shell and a safety protection assembly, the safety protection assembly is arranged on the outer side of the battery pack or between battery cells in the battery pack; the safety protection assembly comprises a nano protection shell and a plastic package layer, the nano protection shell is of a hollow structure and is internally vacuum, and an air inlet and an air outlet are further formed in the surface of the nano protection shell. By adopting the structural design, the heat conductivity coefficient of the nano protective shell which is originally low in heat conductivity coefficient is further reduced, the index requirement of a thermal insulation material is met, integration of the thermal insulation material and a safety protection material is achieved, and integration of two different functions is achieved; the weight of the whole bag is reduced while the integration of the design of the whole bag is improved, and the development cost and the material cost of the whole bag are reduced.

Description

Technical Field

[0001] The present invention relates to the field of battery technology, and in particular to a battery pack and an electrical device. Background Art

[0002] With the rapid popularization of electric vehicles, consumers and automakers are paying more and more attention to battery safety issues. Power batteries are not only the main power source and core components of electric vehicles, but also the main technical barrier to their rapid development. Lithium-ion batteries are widely used in mobile phones, electric vehicles, mobile power supplies and other fields due to their high energy density, high cycle life and high environmental protection.

[0003] Lithium-ion batteries will have a series of safety issues based on many factors such as structural design, material selection, manufacturing process, working performance and external environment. For example: Lithium-ion batteries have inherent thermal risks due to their material and structural characteristics. During long-term charge and discharge cycles, due to objective factors such as lithium dendrites and mechanical abuse, thermal runaway may be triggered to produce a large amount of toxic or highly flammable gases, leading to subsequent violent fires or explosions. In addition, batteries generate heat during the charging and discharging process, and are affected by factors such as charge and discharge rates and operating temperatures, which increase the battery temperature; once the heat cannot be dissipated in time, the battery will experience thermal runaway, and even cause serious safety accidents such as combustion and explosion. For another example, when a battery or battery pack is collided or squeezed due to a traffic accident, the battery will be damaged internally, resulting in thermal runaway, and the internal side reactions will be stimulated, which will also trigger thermal runaway of the battery. All of the above are the root causes of fires in new energy vehicles. In order to prevent the battery from thermally spreading throughout the battery pack due to thermal runaway, which may cause the battery pack to catch fire and explode, posing a huge threat to the safety of passengers, the current process will set up some battery safety structural parts inside the battery pack to suppress or avoid thermal diffusion of the entire pack. These safety structural parts need to have safety features such as heat insulation, insulation, and fire retardancy.

[0004] It is also worth noting that, in addition to the above-mentioned requirements for thermal insulation and flame retardancy, in order to reduce the impact of temperature on the performance of the battery pack in a low-temperature environment, some insulation structures need to be set up in the battery pack; currently, the more commonly adopted measures include arranging an insulation layer in the battery pack. This is mainly because when the lithium-ion battery is in a low-temperature state, its available capacity is reduced and the charging and discharging power is limited; and the lower the ambient temperature, the lower the activity of the active substances in the battery, the higher the internal resistance and viscosity of the electrolyte, the more difficult the ion diffusion, and the slow diffusion rate of lithium ions in the electrode at low temperatures, making it difficult to embed and easy to escape, resulting in a rapid decrease in capacity; it can be seen that using it at low temperatures will have a great impact on the battery life, and an insulation structure is needed to ensure low-temperature electrical performance.

[0005] In summary, in addition to having low thermal conductivity, the insulation material used in the battery pack also needs to be flame retardant, insulating, soft, high temperature resistant, and lightweight because it is placed inside the battery pack to meet the requirements of electrochemical performance and safety performance. However, general battery packs need to be equipped with safety protection materials and insulation materials at the same time, which makes the structure inside the battery pack too complicated; and too complicated structural design will also affect the space layout inside the pack, affect the space occupancy of the battery cell and reduce battery performance, and at the same time increase the design cost of the entire pack.

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

[0007] The first purpose of the present invention is to provide a battery pack, which is mainly used to solve the technical defects of the existing battery structure, such as the safety structural parts for preventing thermal runaway and the thermal insulation functional parts for ensuring low-temperature performance, which will lead to the complex structure in the battery pack, affect the space occupancy of the battery cells, and increase the design cost of the battery pack.

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

[0009] In order to achieve the above-mentioned purpose of the present invention, the following technical solutions are particularly adopted:

[0010] A battery pack comprises a battery pack, a housing and a safety protection component;

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

[0012] The safety protection component comprises a nano protective shell and a plastic sealing layer; the plastic sealing layer is encapsulated on the outside of the nano protective shell; the nano protective shell is 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 comprises the battery pack.

[0014] Compared with the prior art, the present invention has the following beneficial effects:

[0015] The present invention obtains a thermal insulation material with excellent heat-insulating and flame-retardant properties by evacuating the nano protective shell and then coating the outer layer with a plastic sealing layer, which has good safety protection performance and low-temperature resistance. The safety protection component based on the present invention can integrate the thermal insulation design and heat insulation design in the battery pack, improve the integration of the whole package design, and avoid the space interference problem caused by complex structural design; at the same time, due to the reduction of structural design, it not only reduces the weight of the whole package, but also reduces the cost and material cost in the whole package development process; in addition, because it has both thermal insulation and heat insulation design functions, it increases the space share of the battery cell, which can greatly improve the electrochemical performance of the whole package. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

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

[0018] The technical scheme of the present invention will be clearly and completely described below in conjunction with the accompanying drawings and specific embodiments, but it will be understood by those skilled in the art that the following described embodiments are part of embodiments of the present invention, rather than all embodiments, and are only used to illustrate the present invention, and should not be considered as limiting the scope of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative work are within the scope of protection of the present invention. If specific conditions are not specified in the embodiments, they are carried out according to normal conditions or conditions recommended by the manufacturer. If the manufacturer is not specified in the reagents or instruments used, they are all conventional products that can be purchased commercially.

[0019] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0020] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

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

[0022] The battery pack at least includes a battery pack, a shell and a safety protection component. It can be understood that the battery pack is a battery power system composed of multiple battery cells connected in series, parallel or mixed. In some optional embodiments, the battery pack is composed of a single battery cell such as a test battery, a button battery, etc. In this case, the battery pack can be equivalent to the battery cell involved in the present invention; the present invention does not impose any restrictions on the component composition and structural relationship of the battery pack. It can also be understood that the shell is the outermost structural element arranged on the battery pack, which plays a role in supporting the overall mechanical structure and protecting against external damage; the present invention does not impose any restrictions on the shape, material or structure of the shell.

[0023] The position of the safety protection component described in the present invention should be set in combination with the situation of the battery pack; optionally, the safety protection component is set on the outside of the battery pack, or the safety protection component is set between the battery cells in the battery pack.

[0024] As a preferred embodiment, the safety protection component is arranged on the outside of the battery pack, including: the safety protection component is designed to partially cover or fully cover the outside of the battery pack. Since the present invention does not impose any restrictions on the structural appearance of the safety protection component and the battery pack, the battery pack is a rectangular parallelepiped as an example for explanation: the safety protection component can be arranged on the top surface or bottom surface of the battery pack (the top surface and bottom surface are defined here as: the plane where the battery pack is adjacent to the outer shell), or the safety protection component can be arranged on any plane of the battery pack with a relatively large surface area, or the safety protection component covers several adjacent planes of the battery pack.

[0025] Regarding the composition of the safety protection component described in the present invention, the safety protection component at least includes a nano protective shell and a plastic sealing layer. The nano protective shell adopts a material with both safety protection performance and thermal insulation performance, and its function is to achieve the corresponding thermal protection and thermal insulation effects; the plastic sealing layer is encapsulated on the outside of the nano protective shell; the nano protective shell is 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.

[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 in a plastic bag, and the air in the plastic bag is further extracted to obtain the plastic layer attached to the surface of the nano protective shell.

[0027] As a preferred embodiment, the material of the plastic sealing layer includes polyethylene terephthalate (PET), and the molecular weight of the PET is 200 to 30,000, including but not limited to any one of 200, 250, 1,000, 5,000, 10,000, 15,000, 20,000, 25,000, 30,000, etc., or a numerical range consisting of any two of the above.

[0028] As a preferred embodiment, the nano protective shell can be understood as a closed shell prepared based on nanomaterials, the interior of which is a vacuum; the nano protective shell can be obtained by building a nano sheet and then sealing it, or it can be directly prepared based on a nano sheet integration process.

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

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

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

[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., and organic fibers include but are not limited to polyester fibers, nylon fibers, polypropylene fibers, polyimide fibers or certain natural fibers, etc.

[0033] As a further preferred embodiment, the nano material includes the following components by weight: 30-100 parts of nano-scale silicon dioxide, 0.1-30 parts of light-shielding functional components and 0.01-10 parts of reinforcing fiber components. The nano material may also include other functional components, such as components for improving the hardness, toughness and melting point of the plate, and those skilled in the art can prepare them according to actual needs.

[0034] As a further preferred embodiment, the method for preparing the nanomaterial comprises: fully mixing raw material components including nano-scale silica, light-shielding functional components and reinforcing fiber components, and then die-casting to obtain a nano-plate material or an integrated shell material.

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

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

[0037] It can be understood that thermal conductivity refers to the temperature difference of 1K on both sides of a 1m thick material under stable heat transfer conditions. 2 Since the nanomaterial used in the nano protective shell has a very low thermal conductivity, it can effectively avoid heat transfer caused by air convection after vacuuming, so the thermal conductivity will be further greatly reduced. It is a very excellent thermal insulation material while serving as a safety protection material. At the same time, due to the barrier effect of the material itself, the heat can be kept on one side of the material and not easily dissipated, thereby playing a good role in heat preservation and insulation.

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

[0039] For the air inlet and the air outlet of the nano protective shell of the present invention, although there is an "air port" structure, the plastic sealing layer arranged on the outside of the nano protective shell can meet the internal vacuum of the nano protective shell under normal conditions. The normal state involved here refers to the state in which there are no safety hazards or thermal runaway of the battery cell in the operation, standby or charging and discharging scenarios of the battery. At this time, the air inlet and the air outlet are both closed by the plastic sealing layer to meet the internal vacuum state of the nano protective shell.

[0040] Correspondingly, when thermal runaway occurs in the battery cell, the battery cell sprays valves and generates a large amount of high-temperature gas, and a special exhaust channel must be set up to discharge the gas from the package in time; that is, the high-temperature gas breaks through the plastic sealing layer corresponding to the air inlet based on the air pressure effect, enters the vacuum inner cavity of the nano protective shell, and when the air pressure value in the inner cavity accumulates to a certain level, it breaks through the plastic sealing layer corresponding to the air outlet and is discharged through the air outlet.

[0041] As a preferred implementation manner, the air inlet is close to the explosion-proof valve of the battery cell, and the air outlet is close to the explosion-proof valve of the housing.

[0042] As a preferred embodiment, when the number of the battery 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 close to the battery cells; in some other embodiments, the number of the safety protection components is also greater than 1 to meet the exhaust requirements of several battery cells; in some other embodiments, not every exhaust valve of the battery cell has a corresponding air inlet.

[0043] like Figure 1 A schematic diagram of a battery pack structure is shown.

[0044] exist Figure 1 The battery pack includes two battery cells. The nano protective shell in the safety protection component covers the three outer sides of the two battery cells. The nano protective shell itself forms a hollow structure with a vacuum exhaust channel inside. When a battery cell experiences thermal runaway, two independent air inlets can respectively supply the gas produced by the thermal runaway to enter the exhaust channel, and discharge it from the outlet adjacent to the explosion-proof valve of the battery pack's outer shell, thereby realizing the electrical and thermal separation of the entire pack after thermal runaway and improving the safety performance of the battery pack design.

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

[0046] It is understandable that, for the plastic sealing layer described in the present invention, when thermal runaway occurs, at the air inlet corresponding to the thermal runaway, the plastic sealing layer and the protective film will be immediately broken due to the impact of the instantaneous high-temperature and high-pressure gas; at the same time, because the temperature and pressure of the gas are significantly lower when it refluxes than when it just enters the interior of the nano protective shell, the plastic sealing layer and the protective film above other battery cells will not be opened, thus avoiding the impact on other battery cells. In the safety protection component with an air inlet>1, in order to ensure that the gas entering the interior of the nano protective shell is discharged at the air outlet (rather than at other air inlets corresponding to no thermal runaway), the protective film is added at the air inlet to achieve the cumulative airflow to be discharged at the air outlet that is most affected by the pressure difference and has the weakest protection.

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

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

[0049] First, when the ambient temperature of the package is normal, there is no thermal runaway of the battery cells and the entire package works normally; the design of the entire package 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 has thermal runaway, the entire package is partially or completely powered off. At the same time, timely exhaust is performed based on the safety protection component to discharge the high-temperature and high-pressure gas out of the package in time, meeting the design requirements and national standards for the entire package to prevent fire and explosion.

[0051] Third, when the battery pack is in an external low-temperature environment, the vacuum insulation structure of the safety protection component can store the heat in the battery pack, so that the temperature of the battery cell is maintained in a suitable temperature range. On the one hand, the charging speed of the battery cell can be improved, and on the other hand, the discharge capacity of the battery cell can be fully utilized to improve the endurance of the electrical equipment.

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

[0053] The electric equipment includes the battery pack. It is understandable that the electric equipment can be any equipment or device that relies on electric 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 electric equipment equipped with the battery pack can belong to an embodiment of the present invention. In some optional embodiments, the electric equipment can also include a power source component other than the battery pack.

[0054] Although the present invention has been illustrated and described with specific embodiments, it should be appreciated that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Those skilled in the art should understand that the technical solutions described in the above embodiments may be modified, or some or all of the technical features thereof may be replaced by equivalents without departing from the spirit and scope of the present invention. However, these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention. Therefore, this means that all such replacements and modifications 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 a safety protection component; The safety protection component is arranged outside the battery pack, or the safety protection component is arranged between the battery cells in the battery pack; The safety protection component comprises a nano protective shell and a plastic sealing layer; the plastic sealing layer is encapsulated on the outside of the nano protective shell; the nano protective shell is 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 nano materials; wherein the nano materials include nano-scale silicon dioxide, light-shielding functional components and reinforcing fiber components; Preferably, the nano material comprises the following components by weight: 30 to 100 parts of nano-scale silicon dioxide, 0.1 to 30 parts of light-shielding functional components and 0.01 to 10 parts of reinforcing fiber components.

3. 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.

4. The battery pack according to claim 1, characterized in that: The material of the plastic sealing layer includes polyethylene terephthalate; Preferably, the molecular weight of the polyethylene terephthalate is 200-30,000.

5. The battery pack according to claim 1, characterized in that: The assembly of the safety protection assembly comprises the following steps: First, the interior of the nano protective shell is evacuated to a vacuum state, and then the nano protective shell is placed in a plastic bag, and the air in the plastic bag is extracted to obtain the plastic layer attached to the surface of the nano protective shell.

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

7. The battery pack according to claim 1, characterized in that: The air inlet is close to the explosion-proof valve of the battery core, and the air outlet is close to the explosion-proof valve of the shell.

8. The battery pack according to claim 7, characterized in that: When the number of the battery 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 close to the battery cells.

9. The battery pack according to claim 1, characterized in that: A protective film is arranged inside the nano protective shell and at a position corresponding to the air inlet.

10. An electrical device, characterized in that: The electrical equipment comprises the battery pack according to any one of claims 1 to 9.

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