Batteries and electrical devices

Abstract

The embodiments of the present application relate to a battery and an electrical device. The battery includes a housing, a battery cell, and a heating device. The battery cell is located within the housing. The heating device is located within the housing and is disposed outside the battery cell. The heating device includes an exothermic material and a phase change material that wraps the exothermic material. The phase change material is configured to undergo a phase change to expose the exothermic material when the temperature inside the battery cell reaches a threshold, and the exothermic material is configured to undergo an exothermic reaction after exposure to heat the battery cell. The heating device of the embodiments of the present application can ensure that the battery can be charged and discharged normally when the ambient temperature is low.

Description

Technical Field

[0001] The present application relates to the technical field of battery production, and in particular to a battery and an electrical device. Background Art

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

[0003] When the ambient temperature is low, the battery may not be able to charge or discharge normally, resulting in the battery not being able to function properly. Summary of the Invention

[0004] The present application provides a battery and an electrical device, aiming to ensure that the battery can be charged and discharged normally when the ambient temperature is low.

[0005] In a first aspect, the present application provides a battery comprising a housing, battery cells, and a heating device. The battery cells are located within the housing. The heating device is located within the housing and disposed outside the battery cells. The heating device comprises an exothermic material and a phase change material encapsulating the exothermic material. The phase change material is configured to undergo a phase change when the temperature inside the battery cells reaches a threshold, thereby exposing the exothermic material. Upon exposure, the exothermic material is configured to undergo an exothermic reaction to heat the battery cells.

[0006] In an embodiment of the present application, when the temperature inside the battery cell reaches a threshold, the phase change material in the heating device undergoes a phase change and generates latent heat. The phase change material after the phase change will not completely wrap the exothermic material. In other words, the outer surface of the exothermic material is exposed, and the exothermic material can undergo an exothermic reaction. The latent heat generated by the phase change material and the heat generated by the exothermic material synergistically heat the battery cell, preventing the electrolyte in the battery cell from crystallizing and protecting the battery cell; and can enable the battery cell to reach normal charging and discharging temperature. Since a large amount of heat is released during the exothermic reaction, the content requirements of the phase change material and the exothermic material are relatively low, thereby improving the weight energy density of the battery.

[0007] According to one embodiment of the present application, the heating device further includes a first fluid device for providing fluid to the exothermic material to cause an exothermic reaction between the fluid and the exothermic material. Placing the first fluid device within the heating device facilitates providing fluid to the exothermic material when heating the battery cell is required.

[0008] According to one embodiment of the present application, a heating device includes multiple heating sections spaced apart along a first direction. The heating sections define a receiving cavity with an opening, within which an exothermic material and a phase change material are disposed. The opening is configured to communicate with an external second fluid device. This embodiment of the present application can actively control the heat release time of an exothermic reaction based on the fluid delivery conditions, thereby controlling the amount of heat released.

[0009] According to one embodiment of the present application, the heating device includes two heating pipes arranged side by side along a second direction. The two heating pipes are respectively arranged on opposite sides of the heating portion along the second direction. The heating pipes include an inlet and multiple outlets, wherein the second direction is perpendicular to the first direction. The accommodating chamber has two openings opposite each other along the second direction, and the openings are arranged opposite the outlets. In this embodiment of the present application, the provision of two openings facilitates increasing the rate and flow rate of fluid flowing into the accommodating chamber, thereby increasing the heat release rate of the exothermic reaction, thereby enabling rapid heating of the battery cells and shortening the battery startup time.

[0010] According to one embodiment of the present application, the heating portion is a plate-shaped structure, which is advantageous for fitting with the outer surface of the battery cell and increasing the heat exchange area.

[0011] According to one embodiment of the present application, the heating device further includes a packaging material for wrapping the exothermic material, wherein the phase change material is wrapped around the packaging material, wherein the packaging material comprises a breathable polymer material. Wrapping the exothermic material substantially prevents exposure to the exothermic material until the temperature inside the battery cell reaches a threshold. Furthermore, wrapping the exothermic material with the packaging material facilitates replacement of the exothermic material.

[0012] According to one embodiment of the present application, the heating device includes a gelling agent, which is used to form a gel after mixing the phase change material and the exothermic material. Optionally, the gelling agent includes at least one of white carbon black, guar gum, and silica sol. Adding the gelling agent to the heating device can gel the materials inside the heating device, which helps the phase change material fully encapsulate the exothermic material and prevent the exothermic material from reacting prematurely before the temperature inside the battery cell reaches a threshold.

[0013] According to one embodiment of the present application, a phase change material includes a primary energy storage agent and a nucleating agent. The primary energy storage agent comprises a mixture of ammonium chloride, sodium acetate, and ethylene glycol; the nucleating agent comprises sodium tetraborate, diatomaceous earth, or barium chloride. This phase change material can release a relatively large amount of heat at a relatively low temperature.

[0014] According to one embodiment of the present application, the exothermic material includes at least one of calcium oxide particles and iron powder; optionally, the heating device also includes a thermal insulation material. The exothermic material can undergo an exothermic reaction at relatively low temperatures. The thermal insulation material can absorb heat and maintain a constant temperature, relatively increasing the heating time of the battery cell and buffering the heat generated by the exothermic material.

[0015] In a second aspect, the present application provides an electrical device, comprising a battery as provided in any embodiment of the first aspect of the present application, wherein the battery is used to provide electrical energy. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments of the present application. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on the drawings without creative work.

[0017] Figure 1 is a structural schematic diagram of a vehicle provided in one embodiment of the present application;

[0018] Figure 2 is an exploded schematic diagram of a battery provided in some embodiments of the present application;

[0019] Figure 3 is a schematic structural diagram of a battery module provided in some embodiments of the present application;

[0020] Figure 4 is a schematic structural diagram of a battery heating device provided in some embodiments of the present application;

[0021] In the accompanying drawings, the drawings are not necessarily drawn to scale.

[0022] Among them, the reference numerals in the figures are:

[0023] X, first direction; Y, second direction;

[0024] 1. Vehicle; 2. Battery; 3. Controller; 4. Motor; 5. Housing; 51. First housing portion; 52. Second housing portion; 53. Accommodation space; 6. Battery module; 7. Battery cell;

[0025] 8. Heating device; 81. Heating portion; 811. Opening; 82. Heating pipeline; 821. Inlet; 822. Outlet. DETAILED DESCRIPTION

[0026] To make the purpose, technical solutions, and advantages of the embodiments of the present application more clear, the technical solutions in the embodiments of the present application will be clearly described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0027] Unless otherwise defined, all technical and scientific terms used in this application have the same meanings as commonly understood by those skilled in the art to which this application belongs. The terms used in the specification of this application are for the purpose of describing specific embodiments only and are not intended to limit this application. The terms "including" and "having" and any variations thereof in the specification and claims of this application and the above-mentioned drawings are intended to cover non-exclusive inclusions. The terms "first" and "second" in the specification and claims of this application or the above-mentioned drawings are used to distinguish different objects, rather than to describe a specific order or a primary-secondary relationship.

[0028] References to "embodiments" in this application mean that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment of the application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute an independent or alternative embodiment that is mutually exclusive of other embodiments.

[0029] In the description of this application, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," "connected," and "attached" should be understood in a broad sense. For example, they may refer to fixed connections, detachable connections, or integral connections; they may refer to direct connections, indirect connections through an intermediate medium, or internal connections between two components. Those skilled in the art will understand the specific meanings of the above terms in this application based on specific circumstances.

[0030] The term "and / or" in this application simply describes an association between related objects, indicating that three possible relationships exist. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " in this application generally indicates that the related objects are in an "or" relationship.

[0031] In the embodiments of this application, the same reference numerals represent the same components, and for the sake of brevity, detailed descriptions of the same components in different embodiments are omitted. It should be understood that the thickness, length, width, and other dimensions of the various components in the embodiments of this application, as well as the overall thickness, length, width, and other dimensions of the integrated device shown in the drawings are merely illustrative and should not constitute any limitation on this application.

[0032] The term "plurality" used in this application refers to two or more (including two).

[0033] In this application, battery cells may include lithium-ion secondary battery cells, lithium-ion primary battery cells, lithium-sulfur battery cells, lithium-sodium-ion battery cells, sodium-ion battery cells, or magnesium-ion battery cells, etc., and the embodiments of this application do not limit this. Battery cells may be cylindrical, flat, rectangular, or other shapes, etc., and the embodiments of this application do not limit this. Battery cells are generally divided into three types according to the packaging method: cylindrical battery cells, square battery cells, and soft-pack battery cells, and the embodiments of this application do not limit this.

[0034] A battery cell includes an electrode assembly and an electrolyte. The electrode assembly includes a positive electrode sheet, a negative electrode sheet, and a separator. A battery cell primarily operates by the movement of metal ions between the positive and negative electrode sheets. The positive electrode sheet includes a positive current collector and a positive active material layer, with the positive active material layer coated on the surface of the positive current collector. The positive current collector includes a positive current collector portion and a positive electrode tab protruding from the positive current collector portion. The positive current collector portion is coated with the positive active material layer, while at least a portion of the positive electrode tab is not coated with the positive active material layer. Taking a lithium-ion battery cell as an example, the material of the positive current collector can be aluminum, and the positive active material layer includes a positive active material. The positive active material can be lithium cobalt oxide, lithium iron phosphate, ternary lithium, or lithium manganese oxide, among others. The negative electrode plate includes a negative electrode current collector and a negative electrode active material layer, and the negative electrode active material layer is coated on the surface of the negative electrode current collector; the negative electrode current collector includes a negative electrode current collecting portion and a negative electrode tab protruding from the negative electrode current collecting portion, the negative electrode current collecting portion is coated with the negative electrode active material layer, and at least part of the negative electrode tab is not coated with the negative electrode active material layer. The material of the negative electrode current collector can be copper, and the negative electrode active material layer includes a negative electrode active material, and the negative electrode active material can be carbon or silicon, etc. In order to ensure that a large current passes without melting, the number of positive electrode tabs is multiple and stacked together, and the number of negative electrode tabs is multiple and stacked together. The material of the separator can be PP (polypropylene, polypropylene) or PE (polyethylene, polyethylene), etc. In addition, the electrode assembly can be a wound structure or a laminated structure, and the embodiments of the present application are not limited to this.

[0035] The battery referred to in the embodiments of this application refers to a single physical module that includes one or more battery cells to provide higher voltage and capacity. For example, the battery referred to in this application may include a battery module or a battery pack. A battery generally includes a casing that encloses one or more battery cells. The casing prevents liquids or other foreign matter from affecting the charging or discharging of the battery cells.

[0036] During battery use, if the ambient temperature is low, for example, ≤-40°C, the electrolyte in the battery cells may crystallize. The crystallized electrolyte cannot properly transfer metal ions, such as lithium ions, and the metal ions cannot properly migrate between the positive and negative electrodes, causing the battery cells to not charge and discharge normally. Adding phase change material to the battery allows for phase change in low ambient temperatures. This phase change process releases heat, heating the battery cells to normal charge and discharge temperatures.

[0037] The inventors found that when using phase change materials, more phase change materials are needed to release heat to reach the normal charging and discharging temperature of the battery cells. This will cause the phase change materials in the battery to occupy a larger space and reduce the weight energy density of the battery.

[0038] In view of this, an embodiment of the present application provides a technical solution, in which the battery includes a casing, a battery cell and a heating device. The battery cell is located in the casing. The heating device is located in the casing and is arranged outside the battery cell. The heating device includes an exothermic material and a phase change material that wraps the exothermic material. The phase change material is used to undergo a phase change to expose the exothermic material when the temperature inside the battery cell reaches a threshold, and the exothermic material is used to undergo an exothermic reaction after exposure to heat the battery cell. In the embodiment of the present application, an exothermic material is added on the basis of the phase change material. When the temperature inside the battery cell reaches a threshold, a large amount of heat can be released, thereby heating the battery cell so that the battery cell reaches a normal operating temperature. The volume occupied by the exothermic material and the phase change material as a whole is relatively small, thereby ensuring the weight energy density of the battery.

[0039] The technical solutions described in the embodiments of the present application are applicable to electrical devices using batteries.

[0040] Electrical devices may include vehicles, mobile phones, portable devices, laptop computers, ships, spacecraft, electric toys, and electric tools, etc. Vehicles may include fuel vehicles, gas vehicles, or new energy vehicles. New energy vehicles may include pure electric vehicles, hybrid vehicles, or extended-range vehicles, etc. Spacecraft include airplanes, rockets, space shuttles, and spacecraft, etc. Electric toys include fixed or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, etc. Electric tools include metal cutting electric tools, grinding electric tools, assembly electric tools, and railway electric tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete vibrators, and electric planers, etc. The embodiments of the present application do not impose any special restrictions on the above-mentioned electrical devices.

[0041] For the convenience of description, the following embodiments are described by taking a vehicle as an example of an electrical device.

[0042] Figure 1This is a schematic diagram of the structure of a vehicle provided by some embodiments of the present application. Figure 1 As shown, a battery 2 is provided inside the vehicle 1, and the battery 2 can be provided at the bottom, head, or tail of the vehicle 1. The battery 2 can be used to power the vehicle 1, for example, the battery 2 can be used as an operating power source for the vehicle 1.

[0043] The vehicle 1 may further include a controller 3 and a motor 4 . The controller 3 is used to control the battery 2 to supply power to the motor 4 , for example, to meet the power requirements of the vehicle 1 during startup, navigation, and driving.

[0044] In some embodiments of the present application, the battery 2 can not only serve as the operating power source of the vehicle 1, but also serve as the driving power source of the vehicle 1, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1.

[0045] Figure 2 Schematic diagram of the explosion of the battery provided in some embodiments of the present application. Figure 2 As shown, the battery 2 includes a box 5 and a battery cell ( Figure 2 The battery cells are housed in the box body 5 .

[0046] The housing 5 is used to accommodate battery cells and can have various structures. In some embodiments, the housing 5 can include a first housing portion 51 and a second housing portion 52. The first housing portion 51 and the second housing portion 52 overlap each other and together define a storage space 53 for accommodating the battery cells. The second housing portion 52 can be a hollow structure with one end open. The first housing portion 51 is a plate-like structure, and the first housing portion 51 overlaps the open side of the second housing portion 52 to form the housing 5 with the storage space 53. The first housing portion 51 and the second housing portion 52 can also each be a hollow structure with one end open. The open side of the first housing portion 51 overlaps the open side of the second housing portion 52 to form the housing 5 with the storage space 53. Of course, the first housing portion 51 and the second housing portion 52 can have various shapes, such as a cylinder, a rectangular parallelepiped, etc.

[0047] In order to improve the sealing performance after the first box body 51 and the second box body 52 are connected, a sealing member, such as a sealant, a sealing ring, etc., may also be provided between the first box body 51 and the second box body 52 .

[0048] Assuming that the first box portion 51 covers the top of the second box portion 52 , the first box portion 51 can also be referred to as an upper box cover, and the second box portion 52 can also be referred to as a lower box.

[0049] In battery 2, there can be one or more battery cells. If there are multiple battery cells, they can be connected in series, in parallel, or in a hybrid configuration. A hybrid configuration refers to a combination of series and parallel connections. Multiple battery cells can be directly connected in series, in parallel, or in a hybrid configuration, and then the entire battery module can be housed within housing 5. Alternatively, multiple battery cells can be first connected in series, in parallel, or in a hybrid configuration to form a battery module 6, and then multiple battery modules 6 can be connected in series, in parallel, or in a hybrid configuration to form a single unit housed within housing 5.

[0050] Figure 3 This is a schematic diagram of the structure of the battery module provided in some embodiments of the present application.

[0051] like Figure 3 As shown, in some embodiments, there are multiple battery cells 7, which are first connected in series, in parallel, or in series to form a battery module 6. The multiple battery modules 6 are then connected in series, in parallel, or in series to form a whole and accommodated in a box.

[0052] The multiple battery cells 7 in the battery module 6 can be electrically connected via a busbar component to achieve parallel connection, series connection, or mixed connection of the multiple battery cells 7 in the battery module 6 .

[0053] Figure 4 Schematic diagram of the structure of a battery heating device provided in some embodiments of the present application.

[0054] like Figures 2 to 4 As shown, the battery 2 provided in the embodiment of the present application includes a housing 5, a battery cell 7, and a heating device 8. The battery cell 7 is located within the housing 5. The heating device 8 is located within the housing 5 and is disposed outside the battery cell 7. The heating device 8 includes an exothermic material and a phase change material encapsulating the exothermic material. The phase change material is configured to undergo a phase change when the temperature inside the battery cell 7 reaches a threshold, thereby exposing the exothermic material. The exothermic material is configured to undergo an exothermic reaction after exposure to heat the battery cell 7.

[0055] The battery cell 7 includes a top surface, side surfaces, and a bottom surface. The side surfaces connect the top surface and the bottom surface. The side surfaces include two first surfaces and two second surfaces that are oppositely disposed. The first surface connects the two second surfaces.

[0056] Battery 2 includes at least one battery cell 7. When there is only one battery cell 7, the heating device 8 can be disposed around the battery cell 7, for example, around the side of the battery cell 7; it can also be disposed on one side of the battery cell 7, for example, outside the first or second side. When there are multiple battery cells 7, the multiple battery cells 7 are arranged side by side, with the second sides of two adjacent battery cells 7 facing each other; the heating device 8 can be disposed on the top or bottom surfaces of the multiple battery cells 7. To improve temperature regulation of the multiple battery cells 7, the heating device 8 can cover the outer surface of the battery cells 7 to the greatest extent possible. The specific location of the heating device 8 can be set according to actual production conditions.

[0057] The heating device 8 may include a chamber containing a phase change material and an exothermic material. When the temperature inside the battery cell 7 reaches a threshold, the phase change material can change state, for example, from a solid to a liquid state, or from a solid to an ultrafine solid state, where the particles are smaller than those in the solid state, to provide latent heat.

[0058] In the embodiment of the present application, when the temperature inside the battery cell 7 reaches a threshold value, the phase change material in the heating device 8 undergoes a phase change and generates latent heat. The phase change material after the phase change will not completely wrap the exothermic material. In other words, the outer surface of the exothermic material is exposed, and the exothermic material can undergo an exothermic reaction. The latent heat generated by the phase change material and the heat generated by the exothermic material synergistically heat the battery cell, preventing the electrolyte in the battery cell 7 from crystallizing, and can protect the battery cell 7; and can enable the battery cell 7 to reach a normal charging and discharging temperature. Since a large amount of heat is released during the exothermic reaction, the content requirements of the phase change material and the exothermic material are relatively low, thereby improving the weight energy density of the battery 2.

[0059] In order to heat the battery cell 7 in time, the threshold value can be set to about -30°C. When the temperature inside the battery cell 7 reaches -30°C, the phase change material undergoes phase change to release heat and exposes the exothermic material, which reacts with the fluid.

[0060] Please continue reading Figure 4 In some embodiments, the heating device 8 may include multiple heating units 81, which are arranged side by side on the outer surface of the battery cell. The multiple heating units 81 operate independently, and when some of the multiple heating units 81 are replaced, the operation of other heating units 81 will not be affected. Optionally, the multiple heating units 81 are arranged at intervals along the first direction X. The multiple heating units 81 are independent of each other and are substantially unaffected by adjacent heating units 81.

[0061] Figure 4 The X direction shown in FIG. 1 represents a first direction, and the Y direction represents a second direction. The first direction X and the second direction Y are perpendicular to each other.

[0062] As some examples, the heating part 81 can be a plate-shaped structure, which is conducive to fitting with the outer surface of the battery cell and increasing the heat exchange area; and the plate-shaped structure can reduce the space occupied by the heating part 81, thereby facilitating improving the energy density of the battery.

[0063] As an alternative example, the heating portion 81 may be a columnar structure. When the temperature inside the battery cell reaches a threshold, the columnar structure can gather heat to heat the battery cell.

[0064] Each heating portion 81 defines a receiving cavity with an opening 811, in which an exothermic material and a phase change material are provided. The opening 811 is used to connect to an external second fluid device. When the temperature inside the battery cell reaches a threshold value, the second fluid device provides fluid to the receiving cavity in a controlled manner, and the fluid and the exposed exothermic material react exothermically to heat the battery cell. By controlling the delivery speed and flow rate of the fluid, the reaction rate and reaction time of the exothermic reaction can be controlled. In other words, the embodiment of the present application can actively control the exothermic time of the exothermic reaction according to the delivery conditions of the fluid, thereby controlling the amount of heat released. In this article, the fluid can be a gas or a liquid. For example, the gas is air or oxygen, etc. The liquid is water or a solution containing water, etc. The exothermic material can react exothermically with the fluid. In this article, a controlled manner means that the second fluid device provides fluid to the receiving cavity under the control of a control device.

[0065] Optionally, the heating device 8 includes two heating pipes 82 arranged side by side along the second direction Y. The two heating pipes 82 are respectively arranged on opposite sides of the heating portion 81 along the second direction Y. The heating pipes 82 include an inlet 821 and multiple outlets 822. The accommodating cavity has two openings 811 opposite each other along the second direction Y, and the openings 811 are arranged opposite the outlets 822. In the embodiment of the present application, the provision of two openings 811 helps to increase the rate and flow rate of fluid flowing into the accommodating cavity, thereby increasing the heat release rate of the exothermic reaction, thereby enabling the battery cells to be heated quickly and shortening the battery startup time.

[0066] In other embodiments, the heating device 8 further includes a first fluid device, which is used to supply fluid to the exothermic material to induce an exothermic reaction between the fluid and the exothermic material. Positioning the first fluid device within the heating device 8 facilitates rapid fluid supply to the exothermic material when heating of the battery cells is required. Optionally, the heating device 8 may further include a control device to control the on / off switching of the first fluid device.

[0067] The phase change material of the embodiments of the present application has the properties of thermal energy storage and temperature regulation. When the temperature inside the battery cell reaches a threshold, it undergoes a phase change, releasing latent heat. The phase change state of the phase change material can change from solid to liquid or even gas, or from solid to ultrafine solid. The change from solid to ultrafine solid can be achieved by utilizing the change from an ordered to a disordered crystal structure to achieve heat release. For example, the phase change material can include wax and a graphite matrix. Alternatively, the phase change material can include a mixture of ammonium chloride, sodium acetate, ethylene glycol, and sodium tetraborate. The mixture of ammonium chloride, sodium acetate, and ethylene glycol serves as the primary energy storage agent. Sodium tetraborate serves as a nucleating agent. The nucleating agent can also be selected from diatomaceous earth or barium chloride, among others. The mass ratio of the aforementioned substances can be based on commonly used ratios in the art, and can be selected as follows: ammonium chloride, sodium acetate, ethylene glycol, and ammonium tetraborate in a mass fraction ratio of 12-18:2-8:1-6:0.2-5. This phase change material can release a relatively large amount of heat at relatively low temperatures.

[0068] Optionally, the heating device 8 further includes a gelling agent, which is used to form a gel after mixing the phase change material and the exothermic material. Furthermore, the gelling agent may include white carbon black, guar gum, or silica sol. Adding the gelling agent to the heating device 8 can form the materials within the heating device 8 into a gel state, which helps the phase change material fully encapsulate the exothermic material and prevent the exothermic material from reacting prematurely before the temperature within the battery cell reaches a threshold.

[0069] The exothermic material can undergo an exothermic reaction to release heat. When coated with the phase change material, the exothermic material does not come into contact with the fluid at all. When the temperature inside the battery cell reaches a threshold, the phase change material exposes the surface of the exothermic material, and the exothermic material and the fluid undergo an exothermic reaction. Optionally, the exothermic material includes at least one of calcium oxide particles and iron powder. Calcium oxide particles and iron powder can undergo an exothermic reaction with the fluid at a relatively low temperature, and the reaction is fast. For example, calcium oxide particles react with water to produce calcium hydroxide. Iron powder reacts with water and oxygen to produce ferrous hydroxide. A large amount of heat is released during the above reaction process.

[0070] Optionally, the heating device 8 may further include a packaging material for wrapping the exothermic material, with the phase change material wrapped around the packaging material. The packaging material comprises a breathable polymer material. Exemplarily, the breathable polymer material comprises polypropylene, etc. Wrapping the exothermic material substantially prevents exposure to the exothermic material until the temperature inside the battery cell reaches a threshold. Furthermore, wrapping the exothermic material with the packaging material facilitates replacement of the exothermic material. Furthermore, since the packaging material comprises a breathable polymer material, fluid can pass through the packaging material, contact the exothermic material, and induce an exothermic reaction.

[0071] Optionally, heating device 8 may also include an insulating material. Exemplarily, the insulating material includes vermiculite or other materials. After the exothermic reaction occurs, the insulating material absorbs heat and maintains a constant temperature, thereby relatively increasing the heating time of the battery cells and buffering the heat generated by the exothermic material.

[0072] Further optionally, the heating device 8 may further include auxiliary materials. For example, the auxiliary materials include activated carbon and the like. The activated carbon can provide a reaction attachment interface for the exothermic material, thereby increasing the contact area between the exothermic material and the fluid.

[0073] The present application is further described below through specific examples.

[0074] Example 1

[0075] Battery

[0076] The battery preparation process is as follows:

[0077] Providing a box body, and arranging a battery cell in the box body;

[0078] A heating device is provided inside the box, and the heating device is provided outside the battery cell, wherein the heating device includes an exothermic material, a phase change material, a gelling agent, and a packaging material. The phase change material includes a main energy storage agent and a nucleating agent that are evenly mixed. The main energy storage agent includes the following components in parts by mass: 12 to 18 parts of ammonium chloride, 2 to 8 parts of sodium acetate, and 1 to 6 parts of ethylene glycol. The nucleating agent includes 0.2 to 5 parts of sodium tetraborate. The exothermic material calcium oxide particles are filled into the packaging material polypropylene, which is then placed into the phase change material to form a mixed solution. The mass ratio of the exothermic material to the phase change material is 0.5 to 5:1. 0.1 to 2 parts of the gelling agent white carbon black are added to the mixed solution, and a gel mixture is formed after mixing.

[0079] Example 2

[0080] The difference from Example 1 is that the exothermic material is iron powder.

[0081] Example 3

[0082] The difference from Example 1 is that the exothermic material is iron powder, and the heating device further comprises insulation materials of vermiculite and activated carbon, wherein the mass ratio of iron powder, vermiculite and activated carbon is 1-50:1-10:1-5.

[0083] Example 4

[0084] Different from Example 1, no packaging material is added to the heating device.

[0085] Example 5

[0086] The difference from Example 1 is that the nucleating agent includes 0.2 to 5 parts of diatomaceous earth.

[0087] Comparative Example 1

[0088] The heating portion contains phase change material, but does not contain exothermic material, gelling agent and packaging material.

[0089] Comparative Example 2

[0090] The battery does not include a heating unit.

[0091] Performance testing:

[0092] 1.Battery weight energy density test standard:

[0093] Use an electronic scale to weigh the battery weight W (unit: kg);

[0094] At 25°C, charge the battery to the maximum rated voltage with a 1 / 3C constant current, then charge it at a constant voltage until the current drops to 0.05C, let it rest for 15 minutes, and then discharge it to the minimum rated voltage with a 1 / 3C constant current, let it rest for 5 minutes. Obtain the battery's discharge energy. Repeat the test three times and take the average value, which is the battery's average discharge energy E (unit: Wh).

[0095] The weight energy density of a battery = E / W.

[0096] 2. Measurement of internal temperature of battery cells

[0097] Under the condition of an ambient temperature of -30°C, water was supplied to the interior of the heating device. After a reaction time of about 10 minutes, the temperature (°C) of the battery cell was measured by a temperature sensor provided on the outer surface of the battery cell.

[0098] The performance test results of Examples 1 to 5 and Comparative Examples 1 and 2 are shown in Table 1.

[0099] Table 1

[0100]

[0101] As shown in Table 1, in order to ensure normal use of the battery, the weight energy density of Examples 1 to 5 is improved compared with Comparative Example 1. Compared with Comparative Example 2, Examples 1 to 5 can heat the battery cells at a relatively low temperature to ensure normal charge and discharge of the battery cells.

[0102] Although the present application has been described with reference to preferred embodiments, various modifications may be made thereto and components may be replaced with equivalents without departing from the scope of the present application. In particular, the various technical features described in the various embodiments may be combined in any manner as long as there are no structural conflicts. The present application is not limited to the specific embodiments disclosed herein, but includes all technical solutions within the scope of the claims.

Claims

1. A battery, characterized in that: include: Box (5); A battery cell (7) located in the box (5); A heating device (8) is located in the box (5) and is arranged outside the battery cell (7). The heating device (8) includes an exothermic material and a phase change material that wraps the exothermic material. The phase change material is used to undergo a phase change to expose the exothermic material when the temperature inside the battery cell (7) reaches a threshold value, and the exothermic material is used to undergo an exothermic reaction after exposure to heat the battery cell (7).

2. The battery according to claim 1, characterized in that The heating device (8) further comprises a first fluid device, which is used to provide fluid to the exothermic material so that the fluid and the exothermic material undergo an exothermic reaction.

3. The battery according to claim 1, characterized in that The heating device (8) comprises a plurality of heating portions (81) arranged at intervals along a first direction (X), the heating portions (81) defining a housing cavity having an opening (811), the exothermic material and the phase change material being arranged in the housing cavity, and the opening (811) being used for communicating with an external second fluid device.

4. The battery according to claim 3, characterized in that The heating device (8) comprises two heating pipes (82) arranged side by side along a second direction (Y), the two heating pipes (82) being respectively arranged on two sides of the heating portion (81) opposite to each other along the second direction (Y), the heating pipes (82) comprising an inlet (821) and a plurality of outlets (822), wherein the second direction (Y) is perpendicular to the first direction (X); The accommodating cavity has two openings (811) that are opposite to each other along the second direction (Y), and the openings (811) are arranged opposite to the outflow port (822).

5. The battery according to claim 3, characterized in that The heating portion (81) is a plate-shaped structure.

6. The battery according to any one of claims 1 to 5, characterized in that The heating device (8) further comprises a packaging material for wrapping the exothermic material, the phase change material being wrapped outside the packaging material, wherein the packaging material comprises a breathable polymer material.

7. The battery according to any one of claims 1 to 5, characterized in that The heating device (8) comprises a gelling agent, and the gelling agent is used to form a gel state after mixing the phase change material and the exothermic material.

8. The battery according to claim 7, characterized in that The gelling agent includes at least one of white carbon black, guar gum and silica sol.

9. The battery according to any one of claims 1 to 5, characterized in that The phase change material comprises a main energy storage agent and a nucleating agent. The main energy storage agent comprises a mixture of ammonium chloride, sodium acetate and ethylene glycol; and the nucleating agent comprises sodium tetraborate, diatomaceous earth or barium chloride.

10. The battery according to any one of claims 1 to 5, characterized in that The exothermic material includes at least one of calcium oxide particles and iron powder.

11. The battery according to claim 10, characterized in that The heating device (8) also includes heat-insulating material.

12. An electrical device, characterized in that: The invention comprises a battery (2) according to any one of claims 1 to 11, wherein the battery (2) is used to provide electrical energy.

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