Battery cell heat insulation structure, battery pack and vehicle

Abstract

The utility model belongs to the technical field of battery heat management, and discloses a battery cell heat insulation structure, a battery pack and a vehicle. And the packaging body of the battery cell heat insulation structure is attached to the outer wall of the single battery cell. A closed containing cavity is formed in the packaging body. The package body is made of a polymer material. And the melting point or thermal decomposition temperature of the polymer material is greater than or equal to 100 DEG C and is less than the minimum thermal runaway temperature of the single cell. The cooling liquid is arranged in the containing cavity and can absorb heat. When thermal runaway is generated due to internal defects and / or external structure damage of the single battery cells, one side, close to the single battery cells, of the packaging body is firstly heated to generate phase change, and the single battery cells can be initially and actively cooled on the basis of preventing thermal runaway from spreading; the cooling liquid is boiled and gasified by absorbing heat generated by the single battery cells, so that the single battery cells can be further actively cooled. Therefore, the effect of actively cooling the single battery cells is improved on the basis of not increasing the volume and weight of the battery cell heat insulation structure.

Description

TECHNICAL FIELD

[0001] The utility model relates to battery thermal management technical field especially relates to electric core heat insulation structure, battery package and vehicle. BACKGROUND

[0002] The battery used in electric vehicles is usually lithium ion battery, which is divided into ternary lithium battery and iron lithium phosphate battery. Among them, ternary lithium battery is widely used in high-end electric vehicles due to its high energy density, high charging efficiency and high discharge rate. However, if the single cell is damaged by internal defects and / or external structure, it will cause thermal runaway, which will cause the single cell to rapidly heat up to 800 DEG C or above, and the single cell will rapidly discharge high-temperature flammable gas and / or liquid and / or solid eruption material to ignite the adjacent other single cells. In view of this phenomenon, the prior art usually uses electric core heat insulation structure to separate two adjacent single cells, so as to reduce the risk of igniting other single cells when the single cell is damaged by internal defects and / or external structure, thereby improving the safety of the battery.

[0003] At present, the electric core heat insulation structure in the prior art mainly includes two types: one is to use aerogel pad as heat insulation pad, which has flame retardancy, but when the single cell produces thermal runaway, the aerogel pad cannot actively cool the single cell; the other is to use phase change material to make heat insulation pad, and the phase change material is usually paraffin, which can actively cool the single cell, but when more heat energy needs to be absorbed, the volume of the heat insulation pad needs to be increased accordingly. UTILITY MODEL CONTENTS

[0004] The utility model aims at providing electric core heat insulation structure, battery package and vehicle to solve the above problems of the prior art.

[0005] To achieve this purpose, the utility model adopts the following technical scheme:

[0006] The electric core heat insulation structure comprises:

[0007] The packaging body is attached to the outer wall of the single cell, and the inside of the packaging body forms a closed accommodating cavity. The packaging body is made of polymer material, and the melting point or thermal decomposition temperature of the polymer material is greater than or equal to 100 DEG C and less than the minimum thermal runaway temperature of the single cell.

[0008] The cooling liquid is arranged in the accommodating cavity, and the cooling liquid can absorb heat.

[0009] As a preferred scheme of the above electric core heat insulation structure, the electric core heat insulation structure further comprises:

[0010] A liquid-absorbing element is housed within the receiving cavity; the liquid-absorbing element can absorb at least a portion of the coolant.

[0011] As a preferred embodiment of the above-mentioned cell heat insulation structure, the liquid-absorbing element includes a liquid-absorbing sheet, which is housed within the receiving cavity.

[0012] As a preferred embodiment of the above-mentioned cell heat insulation structure, the mass of coolant absorbed by a single absorbent sheet is m2 = a*b*h*w, (n*m2)≥15g; where m2 is the mass of coolant absorbed by a single absorbent sheet, in g; n is the number of absorbent sheets in the receiving cavity, n is a positive integer greater than or equal to 1; a is the length of the absorbent sheet, in cm; b is the width of the absorbent sheet, in cm; h is the thickness of the absorbent sheet, in cm; and w is the amount of coolant contained in a unit volume of the absorbent sheet, in g / cm³. 3 .

[0013] As a preferred embodiment of the aforementioned cell thermal insulation structure, w≥0.5g / cm 3 ; and / or, the thickness of a single absorbent sheet is in the range of 0.2 mm to 1 mm.

[0014] As a preferred embodiment of the above-mentioned cell insulation structure, the liquid-absorbing element is made of fluff pulp or water-absorbing resin.

[0015] As a preferred embodiment of the above-mentioned cell heat insulation structure, the liquid-absorbing component includes a plurality of liquid-absorbing sheets, which are stacked sequentially along the thickness direction of the liquid-absorbing sheets.

[0016] As a preferred embodiment of the above-mentioned cell thermal insulation structure, the encapsulation body is made of polyethylene, polypropylene, polyimide, polyvinyl chloride, or latex.

[0017] As a preferred embodiment of the above-mentioned cell heat insulation structure, the encapsulation body includes two encapsulation sheets, which are stacked along their own thickness direction, sealed together, and forming the receiving cavity between the two encapsulation sheets.

[0018] As a preferred embodiment of the above-mentioned cell heat insulation structure, the thickness of the encapsulation sheet ranges from 0.08 mm to 1 mm.

[0019] The battery pack includes individual battery cells and the aforementioned cell insulation structure.

[0020] The vehicle, including the aforementioned battery pack.

[0021] The beneficial effects of this utility model are:

[0022] The utility model provides a battery cell heat insulation structure, this battery cell heat insulation structure includes the encapsulation body, the encapsulation body is attached to the outer wall of single cell. The inside of encapsulation body forms the closed accommodating cavity. The encapsulation body is made of polymer material. The melting point or thermal decomposition temperature of polymer material is greater than or equal to 100 DEG C, and less than the minimum thermal runaway temperature of single cell. The cooling liquid is arranged in the accommodating cavity, and the cooling liquid can absorb heat.

[0023] The polymer material has the characteristics of light weight, good thermoplasticity and good thermal stability, so the encapsulation body is made of polymer material, which can reduce the weight of the encapsulation body and make the encapsulation body change phase after being heated to become molten or soft. Specifically, for the encapsulation body made of polymer material with a melting point, the encapsulation body changes from solid to molten state after being heated; for the encapsulation body made of polymer material capable of thermal decomposition, the encapsulation body deforms and even burns to form ash with coke after being heated.

[0024] Since the single cell generates heat during normal operation, the melting point or thermal decomposition temperature of the polymer material is set to be greater than or equal to 100 DEG C, so that the encapsulation body can be effectively prevented from changing from solid to molten state or from softening due to normal heat dissipation of the single cell, resulting in failure of the battery cell heat insulation structure. Secondly, in order to ensure that the encapsulation body can effectively change phase and actively cool when the single cell is in thermal runaway, the melting point or thermal decomposition temperature of the polymer material is set to be less than the minimum thermal runaway temperature of the single cell.

[0025] When the single cell generates thermal runaway due to internal defects and / or damage by external structure, the encapsulation body absorbs heat and changes phase after being heated. For the encapsulation body made of polymer material with a melting point, the encapsulation body changes from solid to molten state after being heated; for the encapsulation body made of polymer material capable of thermal decomposition, the encapsulation body deforms and even burns to form ash with coke after being heated. Therefore, a closed accommodating cavity is formed in the inside of the encapsulation body, and the cooling liquid is stored in the accommodating cavity. When the side of the encapsulation body close to the single cell absorbs heat generated by the single cell and changes phase, the cooling liquid can preliminarily actively cool the single cell while blocking the spread of thermal runaway. When the encapsulation body changes phase and exposes the cooling liquid in the accommodating cavity, the cooling liquid absorbs heat generated by the single cell and boils and vaporizes, so that the single cell can be further actively cooled.

[0026] Therefore, compared with the prior art, the effect of actively cooling the single cell can be further improved without increasing the volume and weight of the battery cell heat insulation structure, so that the risk of affecting the thermal runaway of adjacent single cells can be effectively reduced.

[0027] The utility model also provides a battery pack, including single body electric core, still include the electric core heat insulation structure of above.

[0028] The utility model also provides a vehicle, including above -mentioned battery pack. BRIEF DESCRIPTION OF DRAWINGS

[0029] Figure 1 It is the structure schematic diagram of electric core heat insulation structure provided by the embodiment of the utility model,

[0030] Figure 2 It is the sectional view of electric core heat insulation structure provided by the embodiment of the utility model, Figure 1 ;

[0031] Figure 3 It is the exploded view of electric core heat insulation structure provided by the embodiment of the utility model,

[0032] Figure 4 It is the sectional view of electric core heat insulation structure provided by the embodiment of the utility model, Figure 2 ;

[0033] Figure 5 It is the structure schematic diagram of liquid suction piece provided by the embodiment of the utility model.

[0034] IN THE DRAWINGS

[0035] 1, package body;11, package sheet;111, recess;12, containing cavity;

[0036] 2, liquid suction piece;21, liquid suction sheet. DETAILED DESCRIPTION

[0037] The utility model makes further detailed description in combination with the drawings and embodiment. It can be understood that the specific embodiment described here is only used to explain the utility model, and is not limited to the utility model. In addition, it should be noted that, in order to facilitate the description, only the part related to the utility model is shown in the drawings, not all structures.

[0038] In the description of the utility model, unless another explicit provision and limitation, the term " is connected, " " is connected, " " fixed " should be broad sense understanding, for example, can be fixed connection, can also be detachable connection, or integral;Can be mechanical connection, can also be electrical connection;Can be directly connected, also can be indirectly connected through intermediate medium, can be the communication of two elements or the interaction of two elements. For ordinary skilled in the art, the specific meaning of the above-mentioned terms in the utility model can be understood according to the specific circumstances.

[0039] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0040] In the description of this embodiment, the terms "upper," "lower," "right," etc., refer to the orientation or positional relationship shown in the accompanying drawings. They are used only for ease of description and simplification of operation, 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 this utility model. In addition, the terms "first" and "second" are only used for distinction in description and have no special meaning.

[0041] Currently, the existing battery cell thermal insulation structures are mainly divided into two categories: one is to use aerogel pads as thermal insulation pads. Aerogel pads are flame retardant, but when a single battery cell experiences thermal runaway, the aerogel pads cannot actively cool the single battery cell; the other is to use phase change materials to make thermal insulation pads. Phase change materials are mostly paraffin wax. Although it can actively cool the single battery cell, if more heat energy is to be absorbed, the volume of the thermal insulation pad needs to be increased accordingly.

[0042] This utility model provides a cell heat insulation structure, such as Figure 1 and Figure 2 As shown, the cell thermal insulation structure includes a package body 1, which is attached to the outer wall of the individual cell. A closed receiving cavity 12 is formed inside the package body 1. The package body 1 is made of a polymer material. The melting point or thermal decomposition temperature of the polymer material is greater than or equal to 100°C and less than the minimum thermal runaway temperature of the individual cell. Coolant is disposed within the receiving cavity 12, and the coolant can absorb heat.

[0043] Polymer materials are lightweight, thermoplastic, and thermosetting. Therefore, using polymer materials to make the encapsulation body can reduce the weight of the encapsulation body and cause the encapsulation body 1 to undergo a phase change upon heating, becoming molten or softening. Specifically, for encapsulation body 1 made of a polymer material with a melting point, the encapsulation body 1 will change from a solid to a molten state upon heating; for encapsulation body 1 made of a polymer material that can undergo thermal decomposition, the encapsulation body 1 will soften, deform, or even burn upon heating, forming ash accompanied by coke.

[0044] Since individual battery cells dissipate heat during normal operation, the melting point or thermal decomposition temperature of the polymer material is set to be greater than or equal to 100℃. This effectively prevents the encapsulation body 1 from changing from a solid state to a molten state or softening from a solid state due to normal heat dissipation of the individual battery cell, which could lead to the failure of the cell's thermal insulation structure. Secondly, to ensure that the encapsulation body 1 can effectively undergo a phase change and actively cool down in the event of thermal runaway of the individual battery cell, the melting point or thermal decomposition temperature of the polymer material is set to be lower than the minimum thermal runaway temperature of the individual battery cell.

[0045] When a single battery cell experiences thermal runaway due to internal defects and / or damage from external structures, the encapsulation body 1 absorbs heat and undergoes a phase change upon heating. For encapsulation body 1 made of a polymer material with a melting point, it changes from a solid state to a molten state and flows upon heating. For encapsulation body 1 made of a polymer material capable of thermal decomposition, it softens, deforms, or even burns, forming ash accompanied by coke. Therefore, a closed containment cavity 12 is formed inside the encapsulation body 1, containing coolant. When the side of the encapsulation body 1 closest to the single battery cell absorbs heat generated by the single battery cell and undergoes a phase change, it can initially actively cool the single battery cell while preventing the spread of thermal runaway. When the phase change of the encapsulation body 1 exposes the coolant in the containment cavity 12, the coolant absorbs heat generated by the single battery cell and boils and vaporizes, further actively cooling the single battery cell.

[0046] Therefore, compared with existing technologies, it is possible to further improve the effect of active cooling of individual cells without increasing the volume and weight of the cell insulation structure, thereby effectively reducing the risk of thermal runaway caused by adjacent individual cells.

[0047] It is understandable that for polymer materials with a melting point, the melting point is greater than or equal to 100℃ and less than the minimum thermal runaway temperature of a single battery cell. For polymer materials with a thermal decomposition temperature, the thermal decomposition temperature is greater than or equal to 100℃ and less than the minimum thermal runaway temperature of a single battery cell.

[0048] Specifically, in this invention, melting point refers to the temperature at which an object changes from a solid state to a molten state.

[0049] Specifically, in this invention, thermal decomposition temperature refers to the temperature at which an object changes from a solid state to a soft state or even burns to form ash accompanied by coke.

[0050] Specifically, the phase transition refers to: a substance suddenly changes from one phase to another phase under the continuous change of external parameters (such as temperature, etc.). In the utility model, the phase transition specifically refers to: the packaging body 1 changes from a solid state to a molten state; or, the packaging body 1 changes from a solid state to soft or even burns to form ash with coke.

[0051] Optionally, the packaging body 1 is made of a thermoplastic material. When the single battery cell generates thermal runaway due to internal defects and / or is damaged by external structures, the thermoplastic material absorbs heat and changes phase from a solid state to a molten state, so that the cooling liquid in the accommodating cavity 12 can be exposed. As an alternative, the packaging body 1 is made of latex. For the packaging body 1 made of latex, when the single battery cell generates thermal runaway due to internal defects and / or is damaged by external structures, the latex absorbs heat and changes phase from a solid state to soft deformation or even burns to form ash with coke, so that the cooling liquid in the accommodating cavity 12 can be exposed.

[0052] Specifically, for the packaging body 1 made of a thermoplastic material, the packaging body 1 can be made of the following thermoplastic materials: the packaging body 1 is made of polyethylene. As an alternative, the packaging body 1 is made of polypropylene. As an alternative, the packaging body 1 is made of polyimide. As an alternative, the packaging body 1 is made of polyvinyl chloride. The packaging body 1 is made of polyethylene or polypropylene or polyimide or polyvinyl chloride, so that the packaging body 1 can absorb heat and change from a solid state to a molten state to actively cool the single battery cell after being heated, and the cooling liquid in the accommodating cavity 12 can be exposed to further actively cool the single battery cell.

[0053] In some embodiments, the packaging body 1 is made of latex. In other embodiments, the packaging body 1 is made of polyethylene. In other embodiments, the packaging body 1 is made of polypropylene. In other embodiments, the packaging body 1 is made of polyimide. In other embodiments, the packaging body 1 is made of polyvinyl chloride.

[0054] Specifically, the melting point of polyethylene changing from a solid state to a molten state is usually between 100℃ and 130℃, and the specific melting point depends on the type and density of polyethylene. For example: the melting point of high-density polyethylene (HDPE, High Density Polyethylene) is relatively high, about 130℃ to 135℃; while the melting point of low-density polyethylene (LDPE, Low Density Polyethylene) is relatively low, about 105℃ to 115℃.

[0055] Specifically, the melting point of polypropylene changing from a solid state to a molten state is usually between 160℃ and 175℃, and the specific melting point depends on its molecular weight and crystallinity.

[0056] Specifically, the melting point of the polyimide is generally between 400℃ to 500℃ when it is transformed from solid state to molten state, and the specific melting point depends on its chemical structure and processing method.

[0057] Specifically, the melting point of the polyvinyl chloride is not a fixed value, and it will undergo different physical state changes during heating, specifically: the polyvinyl chloride starts to soften at 80℃ to 85℃, starts to become viscoelastic when the temperature rises to 130℃, starts to transform into viscous flow state when the temperature reaches 160℃ to 180℃, and finally transforms into molten state.

[0058] It can be understood that the minimum thermal runaway temperature of the single battery cell is different for different types and specifications of single battery cells. Therefore, the material for manufacturing the packaging body 1 is selected according to the minimum thermal runaway temperature of the single battery cell.

[0059] As shown in Figure 1 and Figure 2 , the packaging body 1 includes two packaging sheets 11, the two packaging sheets 11 are overlapped along the thickness direction of the two packaging sheets 11, the two packaging sheets 11 are sealingly connected, and the accommodating cavity 12 is formed between the two packaging sheets 11. To achieve the formation of a closed accommodating cavity 12.

[0060] Specifically, in this embodiment, the two packaging sheets 11 are hot melt connected. So that there is no need to additionally set a connecting structure, and the sealing effect of the formed accommodating cavity 12 is good.

[0061] In this embodiment, the two packaging sheets 11 are independent of each other, the two packaging sheets 11 are overlapped along the thickness direction of the two packaging sheets 11, the four sides of the two packaging sheets 11 are hot melt connected and form the accommodating cavity 12. In other embodiments, the two packaging sheets 11 are single-sidedly connected, the two packaging sheets 11 are overlapped along the thickness direction of the two packaging sheets 11, the remaining three sides of the two packaging sheets 11 are hot melt connected and form the accommodating cavity 12. In other embodiments, the two packaging sheets 11 are single-sidedly connected, the two packaging sheets 11 are overlapped along the thickness direction of the two packaging sheets 11, the four sides of the two packaging sheets 11 are hot melt connected and form the accommodating cavity 12. All can form an accommodating cavity 12 with good sealing effect. It can be understood that for the two packaging sheets 11 which are single-sidedly connected, the two packaging sheets 11 are obtained by folding a packaging sheet 11 with a relatively long length. In other embodiments, a sealing ring can also be provided between the two packaging sheets 11, and the four sides of the two packaging sheets 11 are connected by a buckle connection or other connection methods.

[0062] Further, as shown in Figures 1 to 3As shown, the end face of each of the two packaging sheets 11 close to each other is concavely provided with a groove 111; the accommodation cavity 12 is formed between the two grooves 111. As an alternative, the end face of one packaging sheet 11 close to the end face of the other packaging sheet 11 is concavely provided with a groove 111; the accommodation cavity 12 is formed between the groove 111 and the other packaging sheet 11.

[0063] Preferably, the thickness of the packaging sheet 11 ranges from 0.08 mm to 1 mm. Specifically, the thickness of the packaging sheet 11 can be adaptively set to 0.08 mm, 0.1 mm, 0.3 mm or 1 mm, etc. according to actual working conditions. It can be understood that when the thickness of the packaging sheet 11 is thinner, the time for the heat generated by the thermal runaway monomer battery cell to heat the packaging sheet 11 from solid to molten state is shorter, the efficiency is higher, and the protection effect of thermal runaway is better, but the packaging process of the packaging sheet 11 is more demanding, and the packaging sheet 11 is prone to penetration and other phenomena during hot melt connection. When the thickness of the packaging sheet 11 is thicker, the packaging process of the packaging sheet 11 is easier, but the time for the heat generated by the thermal runaway monomer battery cell to heat the packaging sheet 11 from solid to molten state is longer, the efficiency is lower, and the protection of thermal runaway is less favorable. Among them, 0.08 mm is the minimum thickness corresponding to the process that the packaging sheet 11 can form a closed accommodation cavity 12 through hot melt connection. 0.1 mm to 0.3 mm is the optimal thickness range of the packaging sheet 11 considering the hot melt connection, the time and efficiency of heating from solid to molten state. 1 mm is the maximum thickness corresponding to the time and efficiency of heating from solid to molten state that can guarantee the protection effect of thermal runaway. Therefore, the thickness of the packaging sheet 11 ranges from 0.08 mm to 1 mm. Preferably, the thickness of the packaging sheet 11 ranges from 0.1 mm to 0.3 mm.

[0064] Preferably, the cooling liquid is water. Water can absorb heat when heated to boiling point, and can also absorb heat of vaporization after boiling point, which can effectively improve the effect and efficiency of active cooling of the monomer battery cell. As an alternative, the cooling liquid includes water, and at least one of ethanol, ethylene glycol, propylene glycol, etc. The cooling liquid can absorb heat and prevent freezing. It can be understood that in some embodiments, the cooling liquid is water. In other embodiments, the cooling liquid is a mixture of water and ethanol. In other embodiments, the cooling liquid is a mixture of water and ethylene glycol. In other embodiments, the cooling liquid is a mixture of water and propylene glycol. In other embodiments, the cooling liquid is a mixture of water, ethylene glycol and propylene glycol. And so on.

[0065] Further preferably, the mass of the cooling liquid in the accommodating cavity 12 is m1, and m1≥15g. Specifically, the mass of the cooling liquid in the accommodating cavity 12 is related to the weight and capacity of the single battery cell. The mass of the cooling liquid in the accommodating cavity 12 can be adaptively set to 15g, 20g or 25g, etc. according to the weight and capacity of the actual single battery cell. It can be understood that the greater the weight of the single battery cell, the greater the capacity of the single battery cell, and the greater the mass of the cooling liquid that needs to be set in the accommodating cavity 12; the smaller the weight of the single battery cell, the smaller the capacity of the single battery cell, and the smaller the mass of the cooling liquid that needs to be set in the accommodating cavity 12. Among them, 15g is the mass of the cooling liquid in the accommodating cavity 12 corresponding to the minimum weight and minimum capacity of the single battery cell commonly used by the vehicle, so m1≥15g is set. Among them, the capacity of the single battery cell refers to the size of the charge stored by the single battery cell, which is usually expressed in ampere-hours (Ah) or milliampere-hours (mAh), which reflects the ability of the single battery cell to store electric energy. It can be understood that if the minimum weight and minimum capacity of the single battery cell can be made smaller, the lower limit value of m1 can also be adaptively adjusted to be less than 15g.

[0066] Specifically, taking water as an example, the calculation process of the total heat Q that can be absorbed by the water in the single battery cell heat insulation structure is as follows:

[0067] The heat that can be absorbed by the water when the water absorbs heat to reach the boiling point: Q1=m1*c*(T2-T1); c is the specific heat capacity of water, c=4.18 J / (g·℃); T2 is the boiling point temperature of water, ℃; T1 is the initial temperature of water, ℃.

[0068] The heat that can be absorbed by the water after the water reaches the boiling point: Q2=m1*L; L is the heat of vaporization. Taking the boiling point temperature of water T2=100℃ as an example, L=2260 J / g.

[0069] Then the total heat that can be absorbed by the water in the single battery cell heat insulation structure:

[0070] Q=Q1+Q2=4.18*m1*(T2-T1)+2260*m1=m1*[4.18*(T2-T1)+2260]J.

[0071] Taking the initial temperature of water T1=25℃, 25℃ water as normal temperature water, the boiling point temperature of water T2=100℃, and m1=15g as an example, the total heat that can be absorbed by the water in the single battery cell heat insulation structure:

[0072] Q=Q1+Q2=m1*[4.18*(T2-T1)+2260]=38.6025 KJ.

[0073] Typically, two relatively large, spaced-apart surfaces of a single battery cell are fitted with cell insulation structures. Therefore, for a single battery cell, the total heat absorbed by the water in the two cell insulation structures is:

[0074] 2*Q=2*(Q1+Q2)=m1*[4.18*(T2-T1)+2260]=77.205KJ.

[0075] Preferably, such as Figures 1 to 5 As shown, the cell insulation structure also includes a liquid absorber 2, which is housed within the receiving cavity 12. The liquid absorber 2 can absorb at least a portion of the coolant. It is understood that the liquid absorber 2 acts as a carrier for the coolant, supporting it. When a single cell experiences thermal runaway due to internal defects and / or damage from external structures, a packaging sheet 11 on the encapsulation body 1 closest to the single cell first absorbs the heat generated by the single cell, undergoing a phase change that exposes the liquid absorber 2. At this point, the liquid absorber 2 is stably distributed on the outside of the single cell, and the coolant is also stably distributed on the outside of the single cell. The liquid absorber 2 and the packaging sheet 11 furthest from the single cell relative to the liquid absorber 2 can stably block thermal runaway. Firstly, the coolant in the absorbent component 2 can reliably absorb heat and actively cool the individual battery cells that have experienced thermal runaway. Secondly, the coolant is at least partially absorbed in the absorbent component 2. When a packaging sheet 11 on the packaging body 1 that is close to the individual battery cell first absorbs the heat generated by the individual battery cell and undergoes a phase change, exposing the absorbent component 2, the coverage area of ​​the coolant can be effectively increased. This can effectively improve the efficiency of heat exchange between the coolant and the thermally runaway individual battery cells, thereby effectively improving the efficiency of active cooling of the individual battery cells.

[0076] More preferably, such as Figures 3 to 5 As shown, the liquid-absorbing component 2 includes a liquid-absorbing sheet 21, which is housed within the receiving cavity 12. The liquid-absorbing sheet 21 has a large surface area, which can further increase the coverage area of ​​the coolant, thereby further increasing the efficiency of heat exchange between the coolant and the thermally runaway individual battery cells, so as to further improve the efficiency of active cooling of the individual battery cells.

[0077] In this embodiment, as Figure 5 As shown, the absorbent sheet 21 is a rectangular sheet, which is adapted to the shape of the outer wall of the rectangular single-cell battery. In other embodiments, the absorbent sheet 21 is a cylindrical sheet, etc. When the absorbent sheet 21 is a cylindrical sheet, the cylindrical sheet is adapted to the shape of the cylindrical single-cell battery.

[0078] Specifically, in this embodiment, the mass of coolant absorbed by a single absorbent sheet 21 is m2 = a*b*h*w. For example... Figure 5 As shown, 'a' represents the length of the absorbent sheet 21, in cm; Figure 5As shown, b is the width of the liquid-absorbing sheet 21, cm; h is the thickness of the liquid-absorbing sheet 21, cm; w is the amount of coolant contained in the liquid-absorbing sheet 21 per unit volume, g / cm 3 .

[0079] Further preferably, n*m2≥ 15 g. Wherein m2 is the mass of the coolant absorbed by a single liquid-absorbing sheet 21, g; n is the number of the liquid-absorbing sheets 21 in the accommodating cavity 12, n is a positive integer greater than or equal to 1. In this way, the liquid-absorbing sheets 21 in the accommodating cavity 12 can basically absorb all the coolant in the accommodating cavity 12, so as to further improve the efficiency of heat exchange between the coolant and the thermal runaway single battery cell.

[0080] Further preferably, w≥ 0.5 g / cm 3 It can be understood that the mass of the coolant absorbed by the liquid-absorbing sheet 21 is greater than or equal to half of the volume of the liquid-absorbing sheet 21. In this way, the amount of coolant that can be absorbed by the liquid-absorbing sheet 21 is increased on the basis of minimizing the volume of the liquid-absorbing sheet 21, so as to further reduce the volume of the battery cell heat insulation structure. If w<0.5, the amount of coolant that can be absorbed by the liquid-absorbing sheet 21 is small, and the volume of the liquid-absorbing sheet 21 needs to be set to be large, which is not conducive to preventing the thermal runaway of the single battery cell and is not conducive to the volume of the battery cell heat insulation structure.

[0081] It can be understood that in the present embodiment, the accommodating cavity 12 contains the liquid-absorbing sheet 21 and the coolant. In other embodiments, the accommodating cavity 12 contains only the coolant.

[0082] Preferably, the liquid-absorbing member 2 is made of fluff pulp. The fluff pulp has good liquid-absorbing property; secondly, the fibers of the fluff pulp are long, and the liquid-absorbing member 2 made of the fluff pulp has good strength; thirdly, the cost of the fluff pulp is low. Specifically, in a free absorption state, the fluff pulp can absorb about 8 grams of water per unit volume. As an alternative, the liquid-absorbing member 2 is made of water-absorbing resin. The water-absorbing resin also has good liquid-absorbing property, can absorb several hundred or even several thousand times of liquid than its own weight, and has low cost. It can be understood that other materials with strong liquid-absorbing property can also be used to make the liquid-absorbing member 2.

[0083] Specifically, the thickness and number of absorbent sheets 21 depend on the material of the absorbent sheets 21 and the amount of coolant required to protect against thermal runaway of a single battery cell. In this embodiment, the thickness of a single absorbent sheet 21 is set to a range of 0.2mm to 1mm. The thickness of the absorbent sheet 21 can be adaptively set to 0.2mm, 0.3mm, 0.4mm, or 1mm, etc., according to actual operating conditions. It is understood that for absorbent sheets 21 of the same material, the greater the thickness of the absorbent sheet 21, the greater the mass of coolant it can absorb; the smaller the thickness of the absorbent sheet 21, the smaller the mass of coolant it can absorb, and the lower the cost. However, the greater the thickness of the absorbent sheet 21, the higher the cost and the easier it is to waste raw materials; the smaller the thickness of the absorbent sheet 21, the easier it is to adjust the total thickness of the absorbent sheets 21 to match the required amount of coolant. By increasing or decreasing the number of absorbent sheets 21, the total thickness of the absorbent sheets 21 can be matched with the required amount of coolant, thus avoiding waste of raw materials. Therefore, taking all factors into consideration, the thickness range of the absorbent sheet 21 is set to 0.2mm to 1mm. It is understandable that the thickness range of the absorbent sheet 21 can be adjusted adaptively according to actual working conditions.

[0084] Optionally, such as Figure 5 As shown, there are multiple absorbent sheets 21, which are stacked sequentially along their thickness direction. This allows the total thickness of the absorbent sheets 21 to be matched with the required coolant volume by increasing or decreasing the number of absorbent sheets 21, thus avoiding material waste. Specifically, in this embodiment, as... Figure 5 As shown, multiple absorbent sheets 21 are independent of each other and stacked. This allows for easy adjustment of the total thickness of the absorbent sheets 21 by increasing or decreasing their number. In other embodiments, multiple absorbent sheets 21 are sequentially connected and stacked. That is, multiple absorbent sheets 21 are obtained by folding a single, longer absorbent sheet 21. The total thickness of the absorbent sheets 21 can be adjusted by cutting.

[0085] In other embodiments, the thickness of the absorbent sheet 21 is directly made to the desired thickness. It is understood that the absorbent sheet 21 is formed into a relatively thick absorbent block.

[0086] Specifically, taking two independent encapsulation sheets 11 as an example, when manufacturing the cell heat insulation structure:

[0087] The liquid absorbing sheet 21 is first caused to absorb a predetermined amount of coolant, and then the liquid absorbing sheet 21 absorbing the coolant is laminated on one of the packaging sheets 11 in the thickness direction of the packaging sheet 11, and then another packaging sheet 11 is laminated on the liquid absorbing sheet 21 in the thickness direction of the packaging sheet 11, and then the periphery of the two packaging sheets 11 is sealingly connected so that a containing cavity 12 is formed between the two packaging sheets 11 and the liquid absorbing sheet 21 absorbing the coolant is sealed in the containing cavity 12.

[0088] Exemplarily, taking water as the coolant, when the total thickness of the battery cell thermal insulation structure is 3mm, the mass of the water in the containing cavity 12 is 35.6g, a heat source with a temperature of 796.3℃ is applied to one side of the battery cell thermal insulation structure in the thickness direction, and the heating time is 30 minutes, the temperature of the other side of the battery cell thermal insulation structure in the thickness direction is 101℃ after 30 minutes. The temperature of the other side of the battery cell thermal insulation structure in the thickness direction after 30 minutes is much lower than the temperature 220℃ at which the battery cell is in thermal runaway, so that the thermal runaway of the single battery cell can be effectively blocked. It can be understood that the thickness direction of the battery cell thermal insulation structure, the thickness direction of the packaging sheet 11 and the thickness direction of the liquid absorbing sheet 21 are all parallel.

[0089] The utility model also provides a battery pack, including single battery cell, still include above-mentioned battery cell thermal insulation structure. Through adopting above-mentioned battery cell thermal insulation structure, can effectively promote the use safety of battery pack. Specifically, in this embodiment, the packaging body 1 of battery cell thermal insulation structure is attached to the outer wall of single battery cell by the mode of adhesion. In other embodiments, the battery cell thermal insulation structure can also be clamped between two single battery cells, so that one side wall of the packaging body 1 is attached to one single battery cell and the other side wall of the packaging body 1 is attached to another single battery cell along the thickness direction of the battery cell thermal insulation structure.

[0090] Specifically, the single battery cell includes two opposite and spaced first side walls and two opposite and spaced second side walls. The two first side walls and the two second side walls enclose the outer peripheral wall of the single battery cell. Along the height direction of the single battery cell, the top wall of the single battery cell and the bottom wall of the single battery cell are correspondingly located at the two ends of the outer peripheral wall of the single battery cell. The area of the first side wall is greater than the area of the second side wall.

[0091] Preferably, in this embodiment, the outer side of at least one first side wall is attached with the packaging body 1. In other embodiments, the outer side of at least one second side wall is attached with the packaging body 1. In other embodiments, the outer side of at least one first side wall is attached with the packaging body 1, and the outer side of at least one second side wall is attached with the packaging body 1.

[0092] The utility model also provides a vehicle including the battery pack. By adopting the battery pack, the use safety of the vehicle can be effectively improved.

[0093] Obviously, the above embodiments of the present application are merely examples for clearly illustrating the present application, and are not intended to limit the embodiments of the present application. For those skilled in the art, various obvious changes, re-adjustments and substitutions can be made without departing from the protection scope of the present application. Here, it is not necessary and impossible to enumerate all the embodiments. Any modification, equivalent substitution and improvement made within the spirit and principle of the present application shall be included in the protection scope of the present application claims.

Claims

1. A cell thermal insulation structure, characterized in that, include: The encapsulation body (1) is attached to the outer wall of the single cell; the encapsulation body (1) has a closed receiving cavity (12) inside; the encapsulation body (1) is made of polymer material; the melting point or thermal decomposition temperature of the polymer material is greater than or equal to 100°C and less than the minimum thermal runaway temperature of the single cell; Coolant is disposed in the receiving cavity (12), and the coolant can absorb heat.

2. The cell thermal insulation structure according to claim 1, characterized in that, The cell thermal insulation structure also includes: The liquid suction element (2) is housed in the receiving cavity (12); the liquid suction element (2) can absorb at least a portion of the coolant.

3. The cell thermal insulation structure according to claim 2, characterized in that, The liquid-absorbing element (2) includes a liquid-absorbing sheet (21) which is housed within the receiving cavity (12).

4. The cell heat insulation structure according to claim 3, characterized in that, The mass of coolant absorbed by a single absorbent sheet (21) is m2 = a × b × h × w, (n × m2) ≥ 15g; where m2 is the mass of coolant absorbed by a single absorbent sheet (21), in g; n is the number of absorbent sheets (21) of the absorbent member (2) in the receiving cavity (12), n is a positive integer greater than or equal to 1; a is the length of the absorbent sheet (21), in cm; b is the width of the absorbent sheet (21), in cm; h is the thickness of the absorbent sheet (21), in cm; and w is the amount of coolant contained in a unit volume of the absorbent sheet (21), in g / cm³. 3 .

5. The cell heat insulation structure according to claim 4, characterized in that, w≥0.5g / cm 3 ; and / or, the thickness of a single absorbent sheet (21) ranges from 0.2 mm to 1 mm.

6. The cell heat insulation structure according to any one of claims 2-5, characterized in that: The absorbent element (2) is made of fluff pulp or absorbent resin.

7. The cell heat insulation structure according to any one of claims 2-5, characterized in that, The liquid-absorbing component (2) includes a plurality of liquid-absorbing sheets (21), which are stacked sequentially along the thickness direction of the liquid-absorbing sheets (21).

8. The cell heat insulation structure according to any one of claims 1-5, characterized in that, The encapsulation body (1) is made of polyethylene, polypropylene, polyimide, polyvinyl chloride, or latex.

9. The cell heat insulation structure according to any one of claims 1-5, characterized in that, The encapsulation body (1) includes two encapsulation sheets (11), which are stacked along their own thickness direction, sealed together, and forming the receiving cavity (12) between the two encapsulation sheets (11).

10. The cell thermal insulation structure according to claim 7, characterized in that, The encapsulation body (1) includes two encapsulation sheets (11), which are stacked along their own thickness direction, sealed together, and forming the receiving cavity (12) between the two encapsulation sheets (11).

11. The cell thermal insulation structure according to claim 9, characterized in that, The thickness range of the encapsulation sheet (11) is 0.08 mm to 1 mm.

12. The cell thermal insulation structure according to claim 10, characterized in that, The thickness range of the encapsulation sheet (11) is 0.08 mm to 1 mm.

13. A battery pack, comprising individual battery cells, characterized in that, It also includes the cell heat insulation structure as described in any one of claims 1-12.

14. A vehicle, characterized in that, Includes the battery pack as described in claim 13.

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