Heat insulation pad, battery and electric device

Abstract

The utility model relates to a heat insulation pad, a battery and an electric device. The heat insulation pad comprises a heat insulation pad body and a strain detection piece, wherein the strain detection piece is arranged on the heat insulation pad body. The thermal insulation pad is applied to the battery and has the effect of retarding thermal runaway of the battery, and the state of the battery in the using process can be accurately obtained through the strain detection piece arranged in the thermal insulation pad.

Description

Technical Field

[0001] The present application relates to the field of battery technology, and in particular to a thermal insulation pad, a battery and an electrical device. Background Art

[0002] With the development of new energy technologies, batteries are being used more and more widely in the market, and people are demanding higher and higher requirements for battery performance, such as higher and higher requirements for energy density. However, battery cells with higher energy density have large residual energy after thermal runaway. When one of the battery cells thermally runs away, its heat will continue to transfer from one battery cell to the adjacent battery cell, thereby causing heat diffusion of the entire battery and causing damage to the entire battery. Therefore, how to know the battery status and slow down the battery thermal runaway is an urgent problem to be solved. Utility Model Content

[0003] Based on this, it is necessary to provide a thermal insulation pad, a battery and an electrical device in order to know the state of the battery and prevent the battery from thermal runaway.

[0004] In a first aspect, the present application provides a thermal insulation pad, comprising:

[0005] The insulation pad body; and

[0006] The strain detection component is arranged on the thermal insulation pad body.

[0007] The above-mentioned thermal insulation pad of the present application can be applied to batteries and has the function of slowing down thermal runaway of batteries. In addition, a strain detection part is set on the thermal insulation pad body, and the pressure parameters of the thermal insulation pad can be obtained according to the electrical signal output by the strain detection part. In this way, when the thermal insulation pad is applied to the battery, the expansion state of the battery during use can be known through the strain detection part, and whether the packaging layer is crushed and failed during the use of the battery can also be known. In this way, the state of the battery during use can be accurately obtained through the strain detection part set in the thermal insulation pad.

[0008] In some embodiments, the thermal insulation pad body includes an outer thermal insulation layer, and the strain detection component is located inside the outer thermal insulation layer, or is disposed on the outer surface of the outer thermal insulation layer. In some embodiments, the strain detection component is disposed on the outer surface of the outer thermal insulation layer, and the thermal insulation pad further includes a waterproof protective film, and the waterproof protective film is disposed on the outer surface of the strain detection component.

[0009] In some embodiments, the strain detection member has an external wire, and the external wire is led out from one side of the outer insulation layer.

[0010] In some embodiments, the thermal insulation pad satisfies at least one of the following conditions:

[0011] (1) The ratio of the thickness of the strain detection member to the thickness of the outer insulation layer is 1:(500~10);

[0012] (2) The thickness of the strain detection element is 10 μm to 50 μm;

[0013] (3) The thickness of the outer insulation layer is 0.5 mm to 8 mm;

[0014] (4) The outer thermal insulation layer meets the following conditions: thermal conductivity at 25°C ≤ 0.020 W / m·K, thermal conductivity at 200°C ≤ 0.027 W / m·K, thermal conductivity at 300°C ≤ 0.035 W / m·K, and thermal conductivity at 500°C ≤ 0.080 W / m·K;

[0015] (5) The density of the outer insulation layer is 0.2~0.22g / cm 3 ;

[0016] (6) The outer thermal insulation layer includes at least one of thermal insulation felt and thermal insulation coating;

[0017] (7) The outer insulation layer is a ceramic material layer;

[0018] (8) The strain of the outer insulation layer when subjected to a stress of 0.5-5 MPa is 25%-70%;

[0019] (9) The thermal insulation pad further includes a release adhesive layer, and the release adhesive layer includes an adhesive layer and a release film. The adhesive layer is arranged on the outer surface of the outer thermal insulation layer, and the release film is arranged on the outer surface of the adhesive layer.

[0020] In some embodiments, the thermal insulation pad body also includes a composite phase change layer, which includes a phase change material layer and an encapsulation layer, and the encapsulation layer is arranged on the outer peripheral side of the phase change material layer; the outer thermal insulation layer is arranged on at least one side of the composite phase change layer.

[0021] The outer thermal insulation layer is arranged on at least one side of the composite phase change layer. The phase change material layer in the encapsulation layer can absorb the heat transferred from the outer thermal insulation layer to play a thermal insulation role. On the other hand, the encapsulation layer is arranged on the outer peripheral side of the phase change material layer to form a composite phase change layer, so that the phase change material layer in the composite phase change layer is physically isolated from the outer thermal insulation layer. Therefore, before the encapsulation layer fails, the phase change material will not diffuse into the inner part of the outer thermal insulation layer to form a heat conduction path, and will not change the structure of the outer thermal insulation layer and its thermal insulation performance, thereby improving the thermal insulation performance of the thermal insulation pad.

[0022] In some embodiments, the strain detection member has a first surface away from the composite phase change layer, the outer heat insulation layer has a second surface away from the composite phase change layer, and the distance between the first surface and the second surface is ≥0.3 mm.

[0023] In some embodiments, the distance between the first surface and the second surface is 0.3 mm to 0.5 mm.

[0024] In some embodiments, the thermal insulation pad satisfies at least one of the following conditions:

[0025] (1) The thickness of the encapsulation layer is 0.1 mm to 0.3 mm;

[0026] (2) The thickness of the composite phase change layer is 1 mm to 6 mm;

[0027] (3) The thickness of the phase change material layer accounts for 70% to 96% of the total thickness of the composite phase change layer;

[0028] (4) The thickness ratio of the composite phase change layer to the outer heat insulation layer is (0.15-12):1;

[0029] (5) The encapsulation layer is an aluminum-plastic film or a polymer encapsulation film;

[0030] (6) The thermal insulation pad further includes an adhesive layer, and the outer thermal insulation layer and the packaging layer are connected via the adhesive layer;

[0031] (7) The outer heat insulation layer is disposed on at least one of the two sides in the thickness direction of the composite phase change layer;

[0032] (8) The length and width of the outer thermal insulation layer are respectively adapted to the length and width of the composite phase change layer; or, at least one of the length and width of the outer thermal insulation layer is greater than the corresponding length or width of the composite phase change layer. In some embodiments, the outer thermal insulation layer includes a first thermal insulation layer and a second thermal insulation layer;

[0033] (9) The strain of the composite phase change layer when subjected to a stress of 0.5-5 MPa is 8%-20%.

[0034] In some embodiments, the outer thermal insulation layer includes a first thermal insulation layer and a second thermal insulation layer;

[0035] The first heat insulation layer and the second heat insulation layer are respectively arranged on both sides of the composite phase change layer in a thickness direction, so that the composite phase change layer is sandwiched between the first heat insulation layer and the second heat insulation layer.

[0036] In some embodiments, edges of the first thermal insulation layer and the second thermal insulation layer are connected to each other to form an assembly cavity, and the composite phase change layer is located in the assembly cavity.

[0037] In some embodiments, an edge of at least one side surface of at least one of the first thermal insulation layer and the second thermal insulation layer forms a convex portion, and the convex portion encloses at least a portion of the assembly cavity.

[0038] In some embodiments, the packaging layer has a packaging margin portion, and the packaging margin portion is folded and located in the assembly cavity.

[0039] In some embodiments, the thermal insulation pad also includes a first sealing frame and a second sealing frame, the first sealing frame is arranged on one side of the first thermal insulation layer, and the second sealing frame is arranged on one side of the second thermal insulation layer, and the first sealing frame and the second sealing frame cooperate to fix the first thermal insulation layer, the composite phase change layer and the second thermal insulation layer.

[0040] In some embodiments, the packaging layer has a packaging margin portion, and the packaging margin portion is located between the first sealing frame and the second sealing frame.

[0041] In some embodiments, the first sealing frame has a first limiting groove, the second sealing frame has a second limiting groove, and the first thermal insulation layer, the composite phase change layer and the second thermal insulation layer are limited in a limiting space formed by the first limiting groove and the second limiting groove.

[0042] In some embodiments, the outer surface of the first heat insulation layer is flush with the outer surface of the first sealing frame, and / or the outer surface of the second heat insulation layer is flush with the outer surface of the second sealing frame.

[0043] In some embodiments, the thermal insulation pad satisfies at least one of the following conditions:

[0044] (1) The strain of the thermal insulation pad when subjected to a stress of 0.5-4 MPa is 15%-35%;

[0045] (2) The thermal insulation pad also includes a third thermal insulation layer, and the composite phase change layer is also provided between the second thermal insulation layer and the third thermal insulation layer.

[0046] In some embodiments, the phase change material layer includes a heat-insulating substrate and a phase change material;

[0047] Wherein, the phase change material is filled in the thermal insulation substrate.

[0048] In some embodiments, the phase change material is filled in the pores of the thermal insulation substrate in the form of phase change microcapsules; the phase change microcapsules include a core material and a wall material, the wall material is wrapped around the outer surface of the core material, and the core material includes the phase change material.

[0049] In a second aspect, the present application provides a battery comprising the above-mentioned thermal insulation pad.

[0050] In some of the embodiments, a plurality of battery cells are further included, and the thermal insulation pad is disposed between at least two adjacent battery cells.

[0051] In some embodiments, the thermal insulation pad is disposed between the large surfaces of two adjacent battery cells.

[0052] In a third aspect, the present application provides an electrical device, comprising the battery as described above. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] FIG1 is a schematic diagram of a cross-sectional structure of a thermal insulation pad according to an embodiment of the present application;

[0054] FIG2 is a schematic diagram of the cross-sectional structure of a thermal insulation pad according to another embodiment of the present application;

[0055] FIG3 is a schematic diagram of the cross-sectional structure of a thermal insulation pad according to another embodiment of the present application;

[0056] FIG4 is a schematic diagram of the cross-sectional structure of a thermal insulation pad according to another embodiment of the present application;

[0057] FIG5 is a schematic diagram of the three-dimensional structure of a thermal insulation pad according to another embodiment of the present application;

[0058] FIG6 is a schematic cross-sectional view of the thermal insulation pad shown in FIG5 taken along the AA direction;

[0059] Figure 7 is a cross-sectional exploded view of the thermal insulation pad shown in FIG6 ;

[0060] FIG8 is a schematic cross-sectional view of a thermal insulation pad according to another embodiment of the present application;

[0061] FIG9 is a schematic structural diagram of a battery according to an embodiment of the present application;

[0062] FIG10 is a schematic diagram of an exploded structure of a battery according to an embodiment of the present application;

[0063] FIG11 is a schematic diagram of the structure of a battery cell in a battery according to an embodiment;

[0064] FIG12 is a schematic diagram of an electrical device using a battery as a power source according to an embodiment of the present application;

[0065] Fig.13 The thermal insulation performance curve of the thermal insulation pad prepared in Example 1;

[0066] Fig.14 The thermal insulation performance curve diagram of the thermal insulation pad prepared in Example 2;

[0067] Fig.15 is a compressive stress-strain curve diagram of a single composite phase change layer in Example 1;

[0068] Fig.16 is a compressive stress-strain curve diagram of the first thermal insulation layer alone in Example 1;

[0069] Fig.17 This is a compressive stress-strain curve diagram of the entire thermal insulation pad in Example 1.

[0070] Description of reference numerals:

[0071] 10. Insulation pad; 11. First insulation layer; 12. Second insulation layer; 13. Composite phase change layer; 131. Phase change material layer; 132. Packaging layer; 1321. Packaging margin; 141. First sealing frame; 142. Second sealing frame; 151. First adhesive layer; 152. Second adhesive layer; 16. Third insulation layer; 17. Strain detection element; 172. External wire;

[0072] 20. Battery cell; 21. Housing; 22. Electrode assembly; 23. Cover plate;

[0073] 30. Battery;

[0074] 40. Electrical equipment. DETAILED DESCRIPTION

[0075] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the present application. However, the present application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present application, so the present application is not limited by the specific embodiments disclosed below.

[0076] In the description of the present application, it should be understood that if the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. appear, the orientation or position relationship indicated by these terms is based on the orientation or position relationship shown in the accompanying drawings, which is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply 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 a limitation on the present application.

[0077] In addition, if the terms "first" or "second" appear, these terms are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of this application, if the term "plurality" appears, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0078] In this application, unless otherwise clearly specified and limited, if the terms "installed", "connected", "connected", "fixed" and the like appear, these terms should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integrated connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to the specific circumstances.

[0079] In the present application, unless otherwise clearly specified and limited, if there is a description that a first feature is "above" or "below" a second feature, etc., or similar descriptions appear, it may mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediate medium. Moreover, the first feature being "above", "above" and "above" the second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. The first feature being "below", "below" and "below" the second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0080] It should be noted that if an element is referred to as being "fixed to" or "disposed on" another element, it may be directly on the other element or there may be a central element. If an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. If any, the terms "vertical", "horizontal", "upper", "lower", "left", "right" and similar expressions used in this application are for illustrative purposes only and do not represent the only implementation method.

[0081] At present, judging from the development of the market situation, the application of batteries is becoming more and more extensive. Batteries, especially power batteries, are not only used in energy storage power systems such as hydropower, thermal power, wind power and solar power stations, but are also widely used in electric vehicles such as electric bicycles, electric motorcycles, electric cars and other fields. With the continuous expansion of the application field of power batteries, the market demand is also constantly expanding.

[0082] A battery cell is the smallest unit that makes up a battery. A battery may include one or more battery cells, and multiple battery cells may be connected in series, in parallel, or in a hybrid connection. Among them, a hybrid connection means that multiple battery cells are connected in both series and in parallel.

[0083] After multiple battery cells are connected to each other and arranged in a certain order, they can be directly placed in a box to assemble into a battery. Alternatively, multiple battery cells can be first assembled into a battery module, and then multiple battery modules are connected to each other to form a whole, and finally the whole battery module is placed in a box to form a battery.

[0084] In order to solve the above-mentioned battery thermal runaway and reduce the damage and risk to the entire battery.

[0085] Please refer to Fig. 1, an embodiment of the present application provides a thermal insulation pad 10, including a thermal insulation pad body and a strain detection member 17. The strain detection member 17 is disposed on the thermal insulation pad body. Further, the strain detection member 17 is disposed inside the thermal insulation pad body, or on the outer surface of the thermal insulation pad body.

[0086] The strain detection member 17 is a component for detecting stress parameters. Generally, it includes a flexible layer and a strain detection element layer arranged on the flexible layer. The flexible layer can deform synchronously with the thermal insulation layer where it is located, and the strain detection element layer can convert the deformation of the flexible layer into an electrical signal output, such as a voltage signal.

[0087] The above-mentioned thermal insulation pad 10 can be applied to batteries and has the function of slowing down thermal runaway of the battery. In addition, a strain detection component 17 is provided on the thermal insulation pad body, and the pressure parameters of the thermal insulation pad 10 can be obtained according to the electrical signal output by the strain detection component 17, that is, the stress of the thermal insulation pad 10 can be monitored. For example, the volume of the battery cell of the battery expands during use, which causes the pressure between adjacent battery cells to change. In this way, when the thermal insulation pad 10 is applied to the battery, the expansion state of the battery during use can be known through the strain detection component 17. In addition, the packaging layer 132 of the thermal insulation pad 10 will also cause the pressure between adjacent battery cells to change before and after failure. Therefore, the strain detection component 17 can also be used to know whether the packaging layer 132 is crushed and failed during the use of the battery. In this way, the state of the battery during use can be accurately obtained through the strain detection component 17 provided in the thermal insulation pad 10.

[0088] In some embodiments, the thermal insulation pad body includes an outer thermal insulation layer. The strain detection element 17 is disposed on the outer thermal insulation layer. Further, the strain detection element 17 can be disposed inside the outer thermal insulation layer or on the outer surface of the outer thermal insulation layer.

[0089] It can be understood that the strain detection member 17 can be arranged inside the outer insulation layer, including but not limited to a part or all of the strain detection member 17 being located inside the outer insulation layer. The strain detection member 17 being located entirely inside the outer insulation layer includes but is not limited to a part of the surface of the strain detection member 17 being flush with the outer insulation layer, that is, the part of the surface is not covered by the insulation layer and is exposed, and also includes the situation where the entire surface of the strain detection member 17 is covered by the outer insulation layer, that is, the strain detection member 17 is located entirely inside the outer insulation layer.

[0090] In some embodiments, the thermal insulation pad body further includes a composite phase change layer 13, the composite phase change layer 13 includes a phase change material layer 131 and an encapsulation layer 132, and the encapsulation layer 132 is arranged on the outer peripheral side of the phase change material layer 131. The outer thermal insulation layer is arranged on at least one side of the outer peripheral side of the encapsulation layer 132.

[0091] In the above-mentioned thermal insulation pad 10, on the one hand, the outer thermal insulation layer is arranged on at least one side of the outer peripheral side of the encapsulation layer 132, and the phase change material layer 131 in the encapsulation layer 132 can absorb the heat transferred from the outer thermal insulation layer to play a role in thermal insulation. On the other hand, the encapsulation layer 132 is arranged on the outer peripheral side of the phase change material layer 131 to form a composite phase change layer 13, so that the phase change material layer 131 in the composite phase change layer 13 is physically isolated from the outer thermal insulation layer, and then before the encapsulation layer 132 fails, the phase change material will not diffuse into the inner part of the outer thermal insulation layer to form a heat conduction path, and then will not change the structure of the outer thermal insulation layer and its thermal insulation performance, so the thermal insulation performance of the thermal insulation pad can be improved. The above-mentioned thermal insulation pad is applied to batteries and has a good effect of slowing down battery thermal runaway.

[0092] Traditional technology is limited by structure, and phase change materials can only use solid phase change materials, but the heat absorption capacity of solid phase change materials is limited. The above-mentioned thermal insulation pad 10, because its phase change material layer 131 is arranged in the packaging cavity of the packaging layer 132, so that the phase change material layer 131 is physically isolated from the first thermal insulation layer 11 and the second thermal insulation layer 12 on both sides, so the phase change material of its phase change material layer 131 can be a solid phase change material, a liquid phase change material or a solid-liquid mixed phase change material. Optionally, the phase change material includes but is not limited to crystal water and salt, phase change molten salt, silicone oil, silica sol, aluminum sol, silica aluminum sol, paraffin, fatty acids, alcohols and other substances that can undergo phase change and absorb heat, and its application range is wider, so it can provide better thermal insulation performance.

[0093] In addition, because the phase change material of the phase change material layer 131 will undergo phase change, for example, the solid phase change material at room temperature will turn into liquid after absorbing heat, the encapsulation layer 132 can also play a role in isolating the phase change material that is liquid after the phase change from the first insulation layer 11 and the second insulation layer 12 on both sides.

[0094] In addition, some preparation processes inevitably cause the phase change material to contain moisture. The structure in which the phase change material layer 131 is arranged in the packaging cavity of the packaging layer 132 can prevent moisture overflow from causing adverse effects on the battery.

[0095] Furthermore, the outer heat insulation layer may be provided on at least one of the two sides in the thickness direction of the composite phase change layer 13 .

[0096] For example, the outer heat insulation layer may be disposed on one side or two opposite sides of the encapsulation layer 132 in the thickness direction of the composite phase change layer 13 .

[0097] In some embodiments, the outer insulation layer includes a first insulation layer 11 and a second insulation layer 12, and the first insulation layer 11 and the second insulation layer 12 are arranged on both sides of the composite phase change layer 13 in the thickness direction, so that the composite phase change layer 13 is sandwiched between the first insulation layer 11 and the second insulation layer 12. In other words, the first insulation layer 11, the composite phase change layer 13, and the second insulation layer 12 are stacked in sequence. The encapsulation layer 132 is arranged on the outer peripheral side of the phase change material layer 131 and constitutes an encapsulation cavity, and the phase change material layer 131 is arranged in the encapsulation cavity.

[0098] The above-mentioned thermal insulation pad 10, on the one hand, is provided with a first thermal insulation layer 11 and a second thermal insulation layer 12 at the same time, which can play a good thermal insulation role; on the other hand, the composite phase change layer 13 is provided between the first thermal insulation layer 11 and the second thermal insulation layer 12, and the composite phase change layer 13 can absorb the heat transferred from the thermal insulation layers on both sides, thereby further improving the thermal insulation performance of the above-mentioned thermal insulation pad 10.

[0099] It is understandable that in other examples, the outer thermal insulation layer may include only the first thermal insulation layer 11 , or only the second thermal insulation layer 12 , and its material and thickness may be the same or similar to those of the first thermal insulation layer 11 or the second thermal insulation layer 12 .

[0100] In some specific examples, the thermal insulation pad 10 is strained by applying pressure. For example, in the process of strain from 0 to point A, the greater the strain, the greater the stress detected by the strain detection member 17. This is the deformation state of the packaging layer 132 in the thermal insulation pad 10 before failure. When reaching point A, the pressure is continued to be applied, the strain continues to increase, and the stress detected by the strain detection member 17 is reduced. This is because the external pressure is too large, causing the packaging layer 132 to collapse and fail, which in turn causes a sudden change in stress and rapid stress relief. After that, as the strain increases, the stress will continue to increase. In this way, the state of the thermal insulation pad 10 can be known by the stage of the stress curve detected by the strain detection member 17. When applied to batteries, the state of the battery cells adjacent to the thermal insulation pad 10 can also be known.

[0101] In the specific example shown in FIG1 , the strain detection element 17 is disposed in the second thermal insulation layer 12, and the strain detection element 17 is entirely located within the second thermal insulation layer 12. It is understood that the strain detection element 17 may also be disposed in the first thermal insulation layer 11, or in both the first thermal insulation layer 11 and the second thermal insulation layer 12.

[0102] Furthermore, the strain detection member 17 has a first surface away from the composite phase change layer 13, and the outer heat insulation layer provided with the strain detection member 17 has a second surface away from the composite phase change layer 13, and the distance between the first surface and the second surface is ≥ 0.3mm, which can be selected as 0.3mm~0.5mmmm, and can be selected as 0.3mm~0.45mm. Among them, the first surface and the second surface are both outer surfaces farther away from the composite phase change layer 13. In this way, the heat insulation pad can not only protect the strain detection member 17, but also does not affect the sensitivity of the strain detection member 17.

[0103] It can be understood that the strain detection element 17 is disposed on the surface of the outer heat insulation layer, which surface may be the surface opposite to the composite phase change layer 13 or the surface opposite to the composite phase change layer 13 .

[0104] Optionally, the strain detection member 17 is disposed on the outer surface of the outer insulation layer, so that the stress change can be responded to more quickly. Furthermore, the insulation pad 10 may also include a waterproof protective film (not shown), which is disposed on the outer surface of the strain detection member 17 to protect the strain detection member 17 from damage by water vapor and extend its service life.

[0105] Furthermore, the strain detection member 17 also has an external wire 172, which is led out from one side of the corresponding insulation layer to connect with the low-voltage connection wire in the battery. Optionally, the external wire 172 is led out from the shorter side of the corresponding insulation layer to facilitate lead-in.

[0106] It can be understood that, generally, the strain detection element 17 also has two external wires 172, through which the strain electrical signal converted from the deformation can be outputted to the outside.

[0107] In some of the embodiments, the ratio of the thickness of the strain detection member 17 to the outer heat insulation layer is 1:(500-10).

[0108] Further, the thickness of the strain detection element 17 is 10 μm to 50 μm. As an example, the thickness of the strain detection element 17 may be 13 μm. It can be understood that the thickness here refers to the sum of the thickness of the flexible layer and the strain detection element layer.

[0109] In some embodiments, the first heat insulating layer 11 is a ceramic material layer. Further, the thickness of the first heat insulating layer 11 is 0.5 mm to 8 mm, and as an example, it can be 0.5 mm, 1 mm, 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm; it can be 1 mm to 8 mm.

[0110] In some embodiments, the second heat insulating layer 12 is a ceramic material layer. Further, the thickness of the second heat insulating layer 12 is 0.5 mm to 8 mm, and as an example, it can be 0.5 mm, 1 mm, 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm; it can be 1 mm to 8 mm.

[0111] Please refer to FIG. 2 . In some embodiments, the thermal insulation pad 10 further includes an adhesive layer, and the outer thermal insulation layer is connected to the encapsulation layer 132 through the adhesive layer. Furthermore, the adhesive layer includes a first adhesive layer 151 and a second adhesive layer 152. The first thermal insulation layer 11 is connected to the encapsulation layer 132 through the first adhesive layer 151; the second thermal insulation layer 12 is connected to the encapsulation layer 132 through the second adhesive layer 152. In this way, the first thermal insulation layer 11, the composite phase change layer 13 and the second thermal insulation layer 12 of the thermal insulation pad 10 are connected and fixed in the thickness direction through the adhesive layer.

[0112] Furthermore, the material of the first adhesive layer 151 and the second adhesive layer 152 are independently silicone adhesive layers, and the thickness is independently 0.04-0.06 mm. The silicone adhesive layer is resistant to high temperatures and has high structural strength. The peeling force of the prepared thermal insulation pad is greater than 10N / cm. The peeling force can be measured by pulling the two sides of the thermal insulation pad with a tensile gauge, and applying a force perpendicular to the thermal insulation pad at 90° to the two sides of the thermal insulation pad. The tensile gauge will display the magnitude of the pulling force when the thermal insulation pad is peeled off, and the peeling force is obtained based on the magnitude of the pulling force.

[0113] In some embodiments, the thermal insulation pad 10 further includes a release adhesive layer (not shown). The release adhesive layer includes a third adhesive layer and a release film, wherein the third adhesive layer is disposed on the outer surface of the outer thermal insulation layer (i.e., the first thermal insulation layer 11 and / or the second thermal insulation layer 12), and the release film is disposed on the outer surface of the third adhesive layer. Thus, when the thermal insulation pad 10 needs to be fixed at a target position, such as a target battery cell, the release film on the surface of the release adhesive layer on the thermal insulation pad 10 is removed, and the thermal insulation pad 10 is simply and conveniently fixed to the target position by bonding with the third adhesive layer, thereby fixing the thermal insulation pad 10.

[0114] As an example, the above-mentioned release adhesive layer is provided on the outer surfaces of the first insulation layer 11 and the second insulation layer 12 of the insulation pad 10. When in use, the insulation pad 10 can be bonded and fixed to two objects respectively through the release adhesive layers on both sides, for example, bonded and fixed to two adjacent battery cells respectively, so that the insulation pad 10 is arranged between the two adjacent battery cells.

[0115] As shown in FIG. 2 , the first thermal insulation layer 11 and the second thermal insulation layer 12 are physically separated by the composite phase change layer 13 . In other words, the edges between the first thermal insulation layer 11 and the second thermal insulation layer 12 are not connected to each other.

[0116] In some embodiments, the length and width of the outer heat insulation layer are respectively adapted to the length and width of the composite phase change layer 13. In other embodiments, at least one of the length and width of the outer heat insulation layer is greater than the corresponding length or width of the composite phase change layer 13.

[0117] Please refer to Fig. 3. In some embodiments, the edges of the first thermal insulation layer 11 and the second thermal insulation layer 12 are connected to each other to form an assembly cavity, and the composite phase change layer 13 is located in the assembly cavity. With this structural setting, the composite phase change layer 13 is arranged inside the first thermal insulation layer 11 and the second thermal insulation layer 12, reducing the risk of the composite phase change layer 13 falling off.

[0118] Further, the edge of at least one side surface of at least one of the first thermal insulation layer 11 and the second thermal insulation layer 12 forms a convex portion, and the convex portion encloses at least part of the assembly cavity. As an example, the edge of at least one side surface of the first thermal insulation layer 11 and the second thermal insulation layer 12 forms a convex portion, and the convex portions of the two are arranged relative to each other and enclose to form an assembly cavity. In the specific example shown in Figure 3, the edges of the four sides of the surface of one side of the first thermal insulation layer 11 and the second thermal insulation layer 12 form a convex portion, and the convex portions of the first thermal insulation layer 11 and the second thermal insulation layer 12 are arranged relative to each other and enclose to form an assembly cavity.

[0119] Generally, the two sides of the phase change material layer 131 are encapsulated by an encapsulation film, and there are encapsulation margins on the sides, such as the following Figure 7That is, the encapsulation layer 132 has an encapsulation margin. When the composite phase change layer 13 is disposed inside the first heat insulation layer 11 and the second heat insulation layer 12, the encapsulation margin is folded and located in the assembly cavity.

[0120] As an example, the encapsulation layer 132 has an encapsulation margin on all four sides.

[0121] Please refer to Fig. 4, in some embodiments, the thermal insulation pad 10 further includes a third thermal insulation layer 16, and a composite phase change layer 13 is also provided between the second thermal insulation layer 12 and the third thermal insulation layer 16. Furthermore, the thermal insulation pad 10 may also include more thermal insulation layers, and the composite phase change layer 13 may also be provided between the second thermal insulation layer 12 and the third thermal insulation layer 16.

[0122] Furthermore, the selection range of the material and thickness of the third thermal insulation layer 16 and other thermal insulation layers can be the same as that of the first thermal insulation layer 11 and the second thermal insulation layer 12; the specific material and specific thickness can be the same or different.

[0123] Please refer to Figures 5 and 6. In some embodiments, the thermal insulation pad 10 also includes a first sealing frame 141 and a second sealing frame 142. The first sealing frame 141 is arranged on one side of the first thermal insulation layer 11, and the second sealing frame 142 is arranged on one side of the second thermal insulation layer 12. The first sealing frame 141 and the second sealing frame 142 cooperate to fix the first thermal insulation layer 11, the composite phase change layer 13 and the second thermal insulation layer 12.

[0124] Further, the first sealing frame 141 and the second sealing frame 142 are independently a rubber frame or a silicone frame. In other words, the materials of the first sealing frame 141 and the second sealing frame 142 are independently rubber or silicone. Further, the first sealing frame 141 and the second sealing frame 142 are both mouth-shaped frames, such as silicone mouth-shaped frames.

[0125] As shown in Figure 6 and Figure 7 In the example shown, the first sealing frame 141 has a first limiting groove (not shown), the second sealing frame 142 has a second limiting groove (not shown), and the first thermal insulation layer 11, the composite phase change layer 13 and the second thermal insulation layer 12 are limited in the limiting space formed by the first limiting groove and the second limiting groove. The first limiting groove and the second limiting groove can limit the first thermal insulation layer 11, the composite phase change layer 13 and the second thermal insulation layer 12 in the thickness direction and radial direction of the thermal insulation pad 10, thereby improving the structural stability of the thermal insulation pad 10. Among them, the radial direction of the thermal insulation pad 10 refers to the direction from the center of the thermal insulation pad 10 to the edge of the thermal insulation pad 10. Furthermore, at this time, the encapsulation margin portion 1321 of the encapsulation layer 132 can be located between the first sealing frame 141 and the second sealing frame 142, such as Figure 7 As shown, the package margin portion 1321 is pressed in the middle by the first sealing frame 141 and the second sealing frame 142 .

[0126] It can be understood that when the above-mentioned first sealing frame 141 and second sealing frame 142 and the above-mentioned first thermal insulation layer 11 and second thermal insulation layer 12 capable of forming an assembly cavity are provided at the same time, the encapsulation margin portion 1321 of the encapsulation layer 132 can pass through between the convex portions of the first thermal insulation layer 11 and the second thermal insulation layer 12 and be located between the first sealing frame 141 and the second sealing frame 142, or the encapsulation margin portion 1321 of the encapsulation layer 132 can also be folded and located in the assembly cavity.

[0127] Please refer to Fig. 8, in other embodiments, the outer surface of the first heat insulating layer 11 is flush with the outer surface of the first sealing frame 141, and / or the outer surface of the second heat insulating layer 12 is flush with the outer surface of the second sealing frame 142. In this way, the thickness of the heat insulating pad 10 can be minimized, the space it occupies can be reduced, and better heat insulating performance can be provided.

[0128] As an example, on the basis of the first adhesive layer 151 and the second adhesive layer 152, the first sealing frame 141 and the second sealing frame 142 can be further used to fix the first thermal insulation layer 11, the composite phase change layer 13 and the second thermal insulation layer 12 around, thereby improving the structural stability of the thermal insulation pad 10. Furthermore, at this time, there is no need for the sealing frame to fix the thickness direction, so the outer surface of the first thermal insulation layer 11 can be flush with the outer surface of the first sealing frame 141, and the outer surface of the second thermal insulation layer 12 can be flush with the outer surface of the second sealing frame 142.

[0129] It can be understood that in some embodiments, the first thermal insulation layer 11, the composite phase change layer 13, the second thermal insulation layer 12, and the third thermal insulation layer 16 can be connected by the above-mentioned adhesive layer, or by the above-mentioned sealing frame, or by both the above-mentioned adhesive layer and the sealing frame, or by none of them, for example, the first thermal insulation layer 11 is directly formed on the encapsulation layer 132 of the composite phase change layer 13.

[0130] Furthermore, the first thermal insulation layer 11, the second thermal insulation layer 12 and the third thermal insulation layer 16 each independently include at least one of thermal insulation felt and thermal insulation coating.

[0131] Furthermore, when any of the above-mentioned thermal insulation layers includes both of the thermal insulation felt and the thermal insulation coating, the thermal insulation coating may be optionally disposed on a side closer to the composite phase change layer 13, specifically, the thermal insulation coating is disposed on the surface of the encapsulation layer 132 of the composite phase change layer 13, and the thermal insulation felt is disposed on a side further away from the composite phase change layer 13. In other words, the thermal insulation coating is directly formed on the surface of the encapsulation layer 132, and the thermal insulation coating is located between the encapsulation layer 132 and the thermal insulation felt.

[0132] For example, in the examples of Figures 1, 3 and 6, the first thermal insulation layer 11 and the second thermal insulation layer 12 are thermal insulation felts, and the third thermal insulation layer 16 is also thermal insulation felt. In other examples, the first thermal insulation layer 11 and the second thermal insulation layer 12 may also be thermal insulation coatings. In comparison, the thickness of the thermal insulation coating is thinner, the overall thickness of the prepared thermal insulation pad is thinner, and the required space is relatively smaller. The thermal insulation layer of the thermal insulation pad 10 can optionally adopt a thermal insulation coating, or a composite of a thermal insulation coating and ceramic felt, which can take into account both a smaller occupied space and better thermal insulation performance.

[0133] Taking FIG1 as an example, when the strain detection member 17 is provided in the second thermal insulation layer 12, a groove for accommodating the strain detection member 17 may be firstly provided in the second thermal insulation layer 12, and after the strain detection member 17 is placed in the groove, thermal insulation felt is filled to cover the strain detection member 17. Specifically, the strain detection member 17 may be fixed to the thermal insulation felt by an adhesive layer.

[0134] For example, in the example shown in FIG. 5 , the first insulation layer 11 and the second insulation layer 12 are insulation felts, and the assembly cavity thereon can be integrally formed when the insulation felts are formed, or can be formed by grooving after the insulation felts are formed.

[0135] It is understood that the thermal insulation felt can be connected to the composite phase change layer 13 through the above-mentioned adhesive layer or sealing frame. The thermal insulation coating can be directly formed on the encapsulation layer 132 in the composite phase change layer 13. As an example, the thermal insulation coating can be prepared by coating the encapsulation layer 132 of the composite phase change layer 13 with a slurry and then drying it to form a coating.

[0136] Furthermore, the thermal insulation felt may be a ceramic thermal insulation felt; further, the thermal insulation coating may be a ceramic thermal insulation coating. It is understood that the ceramic thermal insulation felt and the ceramic thermal insulation coating are both ceramic material layers. In some embodiments, the outer thermal insulation layer is a ceramic material layer. In other words, the first thermal insulation layer 11, the second thermal insulation layer 12, and the third thermal insulation layer 13 are each independently a ceramic material layer.

[0137] The material in the "ceramic material layer" in the present application includes but is not limited to at least one of ceramic oxides, ceramic nitrides, and ceramic carbides. Among them, ceramic oxides include but are not limited to silicon oxide and aluminum oxide, ceramic nitrides include but are not limited to silicon nitride, and ceramic carbides include but are not limited to silicon carbide.

[0138] In some examples, the ceramic material layer may be a stack of one or more of a silicon oxide layer, an aluminum oxide layer, a silicon nitride layer, and a silicon carbide layer.

[0139] Furthermore, the ceramic insulation felt may be a silica aerogel ceramic felt. As an example, the silica aerogel ceramic felt may be prepared by inorganic fiber reinforcement technology to prepare aerogel materials, through impregnation sol, gel, solvent replacement and supercritical drying processes.

[0140] In some of the embodiments, the first thermal insulation layer 11, the second thermal insulation layer 12 and the third thermal insulation layer 16 each independently meet the following conditions: the thermal conductivity at 25°C is ≤0.020W / m·K, the thermal conductivity at 200°C is ≤0.027W / m·K, the thermal conductivity at 300°C is ≤0.035W / m·K, and the thermal conductivity at 500°C is ≤0.080W / m·K.

[0141] In some embodiments, the density of the first thermal insulation layer 11, the second thermal insulation layer 12, and the third thermal insulation layer 16 are independently 0.2-0.22 g / cm 3 .

[0142] In some embodiments, the outer insulation layer is a ceramic material layer.

[0143] In some embodiments, the thickness ratio of the composite phase change layer 13 to the outer heat insulation layer is 0.15-12:1, further 0.5-8:1. For example, it can be 0.15:1, 0.5:1, 1:1, 2:1, 4:1, 6:1, 8:1, 10:1, 12:1.

[0144] Furthermore, the thickness of the outer heat insulation layer is 0.5 mm to 8 mm. As an example, it can be 0.5 mm, 1 mm, 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm; it can be optionally 1 mm to 8 mm.

[0145] Furthermore, the thickness of the first heat insulation layer 11 is 0.5 mm to 8 mm. As an example, it can be 0.5 mm, 1 mm, 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm; it can be 1 mm to 8 mm.

[0146] Furthermore, the thickness of the second heat insulation layer 12 is 0.5 mm to 8 mm. As an example, it can be 0.5 mm, 1 mm, 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm; it can be 1 mm to 8 mm.

[0147] In some of the embodiments, in the total thickness of the composite phase change layer 13, the thickness of the phase change material layer 131 accounts for 70%~96%, and can be optionally 86%~96%. As an example, the thickness may be 70%, 75%, 80%, 82%, 85%, 86%, 90%, 92%, 95%, or 96%.

[0148] In some of the embodiments, the thickness of the composite phase change layer 13 is 1 mm to 6 mm, and can be 1 mm to 4 mm. As an example, it can be 1 mm, 1.5 mm, 2 mm, 2.5 mm, 3 mm, 3.5 mm, 4 mm, 5 mm, 6 mm. It can also be 1.5 mm to 3.5 mm.

[0149] In some of the embodiments, the thickness of the packaging layer 132 is 0.1 mm to 0.3 mm, for example, 0.1 mm, 0.15 mm, 0.2 mm, 0.3 mm, and can be optionally 0.1 mm to 0.15 mm, or 0.2 mm to 0.3 mm.

[0150] In some embodiments, the packaging layer 132 is an aluminum-plastic film or a polymer packaging film.

[0151] Further, the packaging layer 132 includes a polypropylene layer, an aluminum layer, and a nylon layer stacked from inside to outside.

[0152] Furthermore, the polymer packaging film may be a PET film (polyethylene terephthalate film) or a PI film (polyimide film).

[0153] In some embodiments, the phase change material layer 131 includes a heat insulation substrate in addition to the phase change material, and at least part of the phase change material is filled in the pores of the heat insulation substrate. In other words, the pores of the heat insulation substrate are filled with the phase change material.

[0154] The thermal insulation substrate may be a ceramic material substrate, such as ceramic fiber felt.

[0155] Furthermore, in some examples, at least part of the phase change material is directly filled in the pores of the thermal insulation substrate. In other examples, at least part of the phase change material can also be filled in the pores of the thermal insulation substrate in the form of phase change microcapsules. It is understood that in the same thermal insulation substrate, two states of phase change materials can also be included at the same time, one is that the phase change material is directly filled in the pores of the thermal insulation substrate, and the other is that the phase change material is filled in the pores of the thermal insulation substrate in the form of phase change microcapsules.

[0156] It can be understood that the phase change material layer 131 can be obtained by soaking the porous thermal insulation substrate such as ceramic fiber felt in the liquid phase change material, for example, soaking in the molten phase change material and then cooling it or soaking in the phase change material solution and then drying or heat preservation. In addition to absorbing heat, the phase change material layer 131 can also play a role in heat insulation. When the phase change material vaporizes and breaks the packaging layer 132, that is, the thermal insulation pad 10 fails, the thermal insulation substrate in the phase change material layer 131 can continue to play a role in heat insulation. In other words, the phase change material is directly filled in the pores of the thermal insulation substrate.

[0157] In other embodiments, at least part of the phase change material is filled in the pores of the thermal insulation substrate in the form of phase change microcapsules. In other words, the pores of the thermal insulation substrate of the phase change material layer 131 can be filled with phase change microcapsules. The phase change microcapsules include a core material and a wall material, the wall material is wrapped around the outer surface of the core material, and the core material includes a phase change material. It can be understood that in some examples, the pores of the thermal insulation substrate can also be directly filled with phase change materials and the above-mentioned phase change microcapsules at the same time.

[0158] The above-mentioned phase change material layer 131 can be obtained by dispersing phase change microcapsules in a solvent to obtain a phase change microcapsule dispersion, then immersing a thermal insulation substrate in the phase change microcapsule dispersion to fill the phase change microcapsules in the pores of the thermal insulation substrate, and removing the solvent in the phase change microcapsule dispersion.

[0159] In this way, the phase change microcapsules in the phase change material layer 131 absorb heat. When the battery cell thermally runs away, the phase change material in the adjacent insulation pad 10 vaporizes and breaks the packaging layer 132, that is, the insulation pad 10 fails. At this time, the insulation substrate in the phase change material layer 131 can continue to play an insulation role.

[0160] Further, the wall material includes a polymer matrix and ceramic particles filled in the polymer matrix. Further, the mass ratio of the polymer matrix to the ceramic particles is 3:(7-11), and as an example, the mass ratio of the polymer matrix to the ceramic particles can be 3:7, 3:8, 3:9, 3:10, 3:11. By controlling the mass content of the ceramic particles in the wall material to be larger, the pressure resistance and heat insulation capacity of the wall material can be improved.

[0161] Further, the mass ratio of the polymer matrix to the core material is 1:(1.3~1.6). As an example, the mass ratio of the polymer matrix to the core material can be 1:1.3, 1:1.4, 1:1.5, 1:1.6. This can further improve the pressure resistance of the phase change microcapsule. As an example, the polymer matrix can be a phenolic resin matrix. It is understood that the polymer matrix is ​​not limited to this, and can also be any one of polyacrylonitrile resin, melamine formaldehyde resin, and phenolic resin polymer.

[0162] Furthermore, the Dv50 particle size of the phase change microcapsule is 5 to 8 μm. The Dv50 particle size is the volume average particle size Dv50, which indicates the particle size corresponding to when the cumulative volume distribution percentage of the particles reaches 50%, and can be tested by methods known in the art. For example, it can be measured using a laser particle size analyzer (such as Malvern Master Size 3000).

[0163] Furthermore, the thermal conductivity of the wall material at 25° C. is ≥ 0.32 W / mK. Such a wall material has a good thermal conductivity and can better conduct heat to the phase change material inside it.

[0164] Furthermore, the melting point of the wall material is greater than 98° C. The wall material has a relatively high melting point, and can maintain the structural stability of the microcapsule within the phase change temperature range of the phase change material.

[0165] The material selection of the above-mentioned thermal insulation substrate and ceramic particles in this application is the same as the selection range of the above-mentioned ceramic material layer. In some examples, the above-mentioned thermal insulation substrate is a ceramic fiber mat. The ceramic fiber mat has ceramic fibers as the core skeleton, which can not only well infiltrate the liquid phase change material, but also has low thermal conductivity, good high temperature resistance (1280°C), resistance to instantaneous thermal shock, flame retardant properties and mechanical properties, no powdering, and is flexible and resilient, and is compatible with the battery pack manufacturing process.

[0166] In some examples, the thermal insulation substrate includes nano ceramic fibers, which include at least one of silica fibers, alumina fibers, zirconium oxide fibers, silicon aluminum ceramic fibers, boron silicon ceramic fibers, boron aluminum ceramic fibers, and zirconium aluminum silicon ceramic fibers.

[0167] Furthermore, the average diameter of the nano-ceramic fibers is 200-800 nm, and the thickness of the thermal insulation substrate is 1 mm-2 mm.

[0168] In some examples, the ceramic particles include but are not limited to at least one of boron nitride particles, silicon nitride particles, silicon carbide particles, silicon dioxide particles, etc. Further, the Dv50 of the ceramic particles is 60-90 nm. As an example, the Dv50 of the ceramic particles can be any value of 60 nm, 65 nm, 70 nm, 75 nm, 80 nm, 83 nm, 85 nm, 90 nm or between any two values. The silicon dioxide particles of the above specific particle size are conducive to doping and uniform dispersion in the substrate.

[0169] Phase-change microcapsules can be obtained by in-situ polymerization, where the wall material covers the core material. In some examples, the preparation method of phase-change microcapsules includes the following steps: dispersing ceramic particles in water to form an aqueous phase; heating the phase-change material to a molten state to form an oil phase; mixing the aqueous phase and the oil phase, stirring to form a Pickering emulsion, adding the raw materials required for preparing the polymer matrix of the wall material (such as water-soluble polymer monomers or prepolymer aqueous solutions) to the Pickering emulsion, and stirring and polymerizing at room temperature to generate a non-water-soluble polycondensate (i.e., a polymer matrix) with a cross-linked three-dimensional network structure at the interface of the emulsion.

[0170] The polymer matrix of the above material has better compatibility with phase change materials such as paraffin, and also facilitates the uniform dispersion of ceramic particles, thereby ensuring the stability of phase change microcapsules.

[0171] In some embodiments, the phase change material layer 131 in the composite phase change layer 13 includes a heat-insulating substrate and a phase change material, and at least part of the phase change material is filled in the heat-insulating substrate, so that the composite phase change layer 13 has good compression performance. Further, the strain of the composite phase change layer 13 when subjected to a stress of 0.5~5MPa is 8%~20%, and further the strain when subjected to a stress of 0.5~4MPa is 8%~20%. Further, the strain under the above stress is 10%~20%, and further 10%~16%.

[0172] In some embodiments, the strain of the outer insulation layer when subjected to a stress of 0.5-5MPa is 25%-70%, further, the strain of the sample when subjected to a stress of 0.5-3MPa is 25%-70%, and further, the strain of the sample when subjected to a stress of 0.5-2.8MPa is 29%-57%. The outer insulation layer has a certain compression performance and can absorb the battery expansion when the battery expands, thereby further improving the service life and insulation performance of the insulation pad.

[0173] In some embodiments, the thermal insulation pad 10 includes a composite phase change layer 13, a first thermal insulation layer 11 and a second thermal insulation layer 12, and the composite phase change layer 13 is sandwiched between the first thermal insulation layer 11 and the second thermal insulation layer 12. Furthermore, the strain of the thermal insulation pad 10 when subjected to a stress of 0.5~4MPa is 15%~35%, further, the strain when subjected to a stress of 0.5~3MPa is 15%~35%, and further, 15%~30%. In this way, the thermal insulation pad 10 has both good compression performance and thermal insulation performance, so that it has good thermal insulation performance when used in the thermal insulation structure of the battery, prevents the spread of thermal runaway, and can also absorb battery expansion and reduce the risks caused by battery expansion.

[0174] The stress-strain test in this article is obtained by the following test method: the sample to be tested is compressed to a certain pressure at a compression rate of 2mm / min using a press machine under an inlet stress of 0.008MPa, and the compression stress-strain curve is recorded. The test is carried out in an environment with a temperature of 23℃±5℃, a relative humidity of 45% to 75%, and an atmospheric pressure of 86kPa to 106kPa.

[0175] The stress test equipment is the Xiamen Yinghaoda pressure tester, with a measuring pressure range of 1-8KN and a measuring area of ​​300*300mm. Stress = load force / sample area.

[0176] Strain is the percentage value of the thickness change of the sample under stress relative to the initial thickness of the sample. The thickness change of the sample under stress is recorded by a micrometer or pressure tester as the displacement relative to the initial position; the equipment used for the initial thickness of the sample is as follows: Mitutoyo 547-301 thickness gauge, equipment accuracy: ≤0.01mm; during the test, the insulation pad and the Mitutoyo 547-301 thickness gauge are required to be parallel to the ground. The test positions are 5 points in the four corners and the center area, and the average value of the 5 points is taken as the test value. That is, strain = displacement recorded by the micrometer or pressure tester / initial thickness of the sample.

[0177] According to the output load-displacement test raw data of the stress testing equipment, it is converted into stress-strain data and the compressive stress-strain curve is output.

[0178] Please refer to FIG. 9 and FIG. 10 , another embodiment of the present application further provides a battery 30 , which includes any of the above-mentioned thermal insulation pads 10 .

[0179] Furthermore, the battery 30 further includes a plurality of battery cells 20, and the heat insulation pad 10 is disposed between at least two adjacent battery cells 20. Optionally, a heat insulation pad 10 is disposed between any two adjacent battery cells 20.

[0180] It is understandable that the above-mentioned heat insulation pad 10 may also be disposed between the battery cell 20 and the inner wall of the battery 30 shell.

[0181] In some of the embodiments, the battery 30 further includes a third adhesive layer, one side of which is disposed on the outer surface of the outer insulation layer (the first insulation layer 11 and / or the second insulation layer 12) of the insulation pad 10, and the other side is used to bond the insulation pad 10 to a designated position of the battery 30, for example, the other side is bonded to a surface (for example, a larger surface) of the battery cell 20.

[0182] The above-mentioned thermal insulation pad 10 is provided in the battery 30, and its working principle is as follows: In the first stage, after a battery cell 20 in the battery 30 has thermal runaway, the heat is transferred to the adjacent (for example, adjacent) thermal insulation pad 10, and the phase change material layer 131 in the thermal insulation pad 10 absorbs the heat to achieve the effect of slowing down the thermal runaway of the battery. In the second stage, the phase change material layer 131 absorbs heat until a phase change occurs, absorbing a large amount of heat. In the third stage, the encapsulation layer 132 and the phase change material layer 131 fail: the phase change material in the phase change material layer 131 is converted into a gaseous state and breaks the encapsulation layer 132, discharging the high-temperature gas. In the fourth stage, the first thermal insulation layer 11 and the second thermal insulation layer 12 and the optional thermal insulation substrate in the composite phase change layer 13 continue to play a role in thermal insulation.

[0183] The first and second stages are the states before the failure of the thermal insulation pad 10, and the third and fourth stages are the states after the failure of the thermal insulation pad 10. The third and fourth stages are not necessary stages.

[0184] It is understood that the shape of the battery cell 20 includes but is not limited to a square or a cylinder. The thermal insulation pad 10 can be arranged in a manner consistent with the shape of the battery cell 20 .

[0185] In some of the embodiments, the battery cell 20 is square, and the thermal insulation pad 10 is disposed on a side surface of the battery cell 20 with a larger area to increase its contact area and improve the thermal insulation performance.

[0186] Furthermore, the thermal insulation pad 10 is disposed between the large surfaces of two adjacent battery cells 20 .

[0187] In this application, unless otherwise specified, "battery cell 20" refers to a basic unit that can realize the mutual conversion of chemical energy and electrical energy, and further, generally speaking, at least includes a positive electrode sheet, a negative electrode sheet and an electrolyte. During the battery charging and discharging process, active ions are embedded and released back and forth between the positive electrode sheet and the negative electrode sheet. The electrolyte plays the role of conducting active ions between the positive electrode sheet and the negative electrode sheet.

[0188] It is understandable that after a plurality of battery cells 20 are connected to each other and arranged in a certain order, they can be directly placed in a box to assemble into a battery. Alternatively, a plurality of battery cells 20 can be first formed into a battery module, and then a plurality of battery modules are connected to each other to form a whole, and finally the whole battery module is placed in a box to form a battery.

[0189] For example, FIG11 is a battery cell 20 of a square structure as an example. The battery cell 20 includes a shell 21, a cover plate 23 and an electrode assembly 22. The electrode assembly 22 is accommodated in the shell 21. The shell 21 is provided with an opening, and the cover plate 23 is sealed in the opening. The electrode assembly 22 includes a positive electrode sheet, a negative electrode sheet and a separator. The positive electrode sheet, the negative electrode sheet and the separator can be formed by a winding process or a lamination process. Furthermore, the electrode assembly 22 also includes an electrolyte, such as an electrolyte. The electrolyte is infiltrated in the electrode assembly 22. The number of electrode assemblies 22 contained in the battery cell 20 can be one or more, and those skilled in the art can select according to specific actual needs.

[0190] Furthermore, one or both ends of the housing 21 are provided with an opening.

[0191] Further, the housing 21 is a rectangular housing, and the opening direction of the housing 21 is the height direction of the housing 21. Further, both ends of the housing 21 are provided with openings, and the two openings are arranged oppositely along the height direction of the housing 21. Further as a non-limiting example, the height of the housing 21 is 80 mm to 210 mm; further as a non-limiting example, the length of the housing 21 is 90 mm to 240 mm; further as a non-limiting example, the width of the housing 21 is 20 mm to 80 mm.

[0192] Furthermore, the battery cell 20 and the shell 21 are rectangular shells, and the thermal insulation pad 10 is arranged on the side of the battery cell 20 with a larger area, which is perpendicular to the above-mentioned width direction, that is, the side formed by the two sides of the above-mentioned length direction and height direction.

[0193] As a further non-limiting example, the wall thickness of the shell is 0.5 mm to 0.8 mm.

[0194] Furthermore, the housing 21 is an aluminum alloy housing; for example, a three-series aluminum alloy housing or a five-series aluminum alloy housing.

[0195] Furthermore, the aluminum alloy of the three-series aluminum alloy shell includes the following components in mass percentage: aluminum ≥ 99.6%, copper ≤ 0.05%, iron ≤ 0.35%, magnesium ≤ 0.03%, manganese ≤ 0.03%, silicon ≤ 0.25%, titanium ≤ 0.03%, vanadium ≤ 0.05%, zinc ≤ 0.05%, and other single elements ≤ 0.03%.

[0196] Furthermore, the aluminum alloy of the fifth series aluminum alloy shell includes the following components in mass percentage: aluminum ≥ 96.7%, 0.05% ≤ copper ≤ 0.2%, iron ≤ 0.7%, manganese ≤ 1.5%, silicon ≤ 0.6%, zinc ≤ 0.1%, other single element components ≤ 0.05%, and the total composition of other elements ≤ 0.15%.

[0197] Another embodiment of the present application further provides an electrical device, including the above-mentioned battery provided in the present application. The above-mentioned battery can be used as a power source for the electrical device, and can also be used as an energy storage unit for the electrical device. The electrical device may include mobile devices, electric vehicles, electric trains, ships and satellites, energy storage systems, etc., but are not limited thereto. Among them, the mobile device may be, for example, a mobile phone, a laptop computer, etc.; the electric vehicle may be, for example, a pure electric vehicle, a hybrid electric vehicle, a plug-in hybrid electric vehicle, an electric bicycle, an electric scooter, an electric golf cart, an electric truck, etc., but are not limited thereto.

[0198] Fig. 12 is an example of an electric device 40. The electric device 40 is a pure electric vehicle, a hybrid electric vehicle, or a plug-in hybrid electric vehicle, etc. In order to meet the electric device's requirements for high power and high energy density of secondary batteries, a battery pack or a battery module may be used.

[0199] Another example of a device may be a mobile phone, a tablet computer, a notebook computer, etc. Such a device is usually required to be thin and light, and a secondary battery may be used as a power source.

[0200] The following are specific embodiments.

[0201] Hereinafter, the embodiments of the present application will be described. The embodiments described below are exemplary and are only used to explain the present application, and should not be construed as limiting the present application. If no specific techniques or conditions are indicated in the embodiments, the techniques or conditions described in the literature in this area or the product specifications are used. If the manufacturer is not indicated in the reagents or instruments used, they are all conventional products that can be obtained commercially.

[0202] Example 1

[0203] The thermal insulation pad 10 of Example 1, as shown in FIG2, includes a first thermal insulation layer 11, a first adhesive layer 151, a composite phase change layer 13, a second adhesive layer 152 and a second thermal insulation layer 12 which are stacked in sequence. The first thermal insulation layer 11 is connected to the encapsulation layer 132 through the first adhesive layer 151; the second thermal insulation layer 12 is connected to the encapsulation layer 132 through the second adhesive layer 152. The composite phase change layer 13 includes a phase change material layer 131 and an encapsulation layer 132, the encapsulation layer 132 is arranged on the outer surface of the phase change material layer 131 and forms an encapsulation cavity, and the phase change material layer 131 is arranged in the encapsulation cavity.

[0204] Wherein, the first heat insulation layer 11 is a silica aerogel ceramic felt with a thickness of 1 mm;

[0205] The thickness of the first adhesive layer 151 is 0.05 mm; the material is a silicone adhesive layer;

[0206] In the composite phase change layer 13, the phase change material layer 131 includes a heat-insulating substrate and a phase change material filled in the pores of the heat-insulating substrate. The specific composition of the phase change material is shown in Table 1 below; in the phase change material layer 131, the mass content of the total phase change material is 60%. The heat-insulating substrate is a silicon dioxide nano-ceramic fiber felt, and the encapsulation layer 132 is an aluminum-plastic film with a thickness of 0.1 mm; the total thickness of the composite phase change layer 13 is 1 mm.

[0207] The thickness of the second adhesive layer 152 is 0.05 mm; the material is a silicone adhesive layer;

[0208] The second heat insulation layer 12 is a silica aerogel ceramic felt with a thickness of 1 mm.

[0209] Example 2

[0210] The structure and materials of Example 2 are basically the same as those of Example 1, except that the total thickness of the composite phase change layer 13 is 2 mm. Specifically, the thickness of the encapsulation layer 132 remains unchanged, and the thickness of the heat insulation substrate is increased, so that the total thickness of the composite phase change layer 13 is 2 mm, and other parameters remain unchanged.

[0211] Embodiments 3 to 8

[0212] It is basically the same as Example 1, the only difference is the composition and / or ratio of the phase change material, as shown in Table 1.

[0213] Table 1

[0214]

[0215] (I) The thermal insulation performance of the thermal insulation pads prepared in each embodiment was tested.

[0216] The test method is as follows: Heat the heating table to 600°C and maintain this temperature. Install temperature sensing wires on two opposite sides of the insulation pad (a rectangle with a size of 100mm×100mm), place the insulation pad on the heating table, and press the insulation pad with an aluminum plate at a pressure of 3000N. By measuring the temperature of the two sides of the insulation pad within 1200s, the insulation effect of the insulation pad can be determined. Among them, the side of the insulation pad that is in direct contact with the heating table is the hot side, and the other side opposite to the hot side is the cold side. There are 3 temperature sampling points on each side, one is the center point, and the other two are distributed symmetrically with the center point, and the spacing between them is 15mm.

[0217] The test results of Example 1 and Example 2 are as follows: Fig.13 and Fig.14 Among them, there are three curves corresponding to the three sampling points of the hot surface and the cold surface, as shown in the figure, curves 1 to 3 are the hot surface, and curves 4 to 6 are the cold surface.

[0218] from Fig.13 It can be seen that within the test time of 1200s, when the hot surface temperature reaches nearly 600℃, the cold surface temperature does not exceed 150℃ due to the insulation effect of the insulation pad. Especially within the first 300s, although the hot surface temperature rises, the cold surface has a lower temperature platform (about 50℃). As the test time increases and the heat diffuses further, the cold surface temperature rises and basically maintains a temperature platform near 100℃. The platform temperature is shown in Table 1.

[0219] from Fig.14 It can be seen that within the test time of 1200s, when the hot surface temperature reaches nearly 600℃, due to the heat insulation effect of the insulation pad, the cold surface temperature is preferably not more than 140℃. Especially within the first 600s, although the hot surface temperature rises, the cold surface has a lower temperature platform (about 50℃). As the test time increases and the heat diffuses further, the temperature of the cold surface rises and basically maintains a temperature platform near 100℃, which is the phase change temperature.

[0220] As can be seen from Table 1, by adjusting the composition and proportion of the phase change material, the phase change temperature of the phase change material layer can be adjusted to meet the needs of different battery cells.

[0221] (ii) 0.05 kg of the thermal insulation pad prepared in Example 2 was taken for phase change heat absorption calculation, and the same weight of water was used for heat absorption comparison. The results showed that the heat absorption capacity of the thermal insulation pad was approximately equal to 83% of the same mass of water, which means that 30% of the heat transferred to the adjacent battery cells can be absorbed by the thermal insulation pad. The heat absorption capacity of the thermal insulation pad of the present application is roughly equivalent to that of water with a larger specific heat capacity, but it is more friendly to the battery than using water as a phase change material.

[0222] Embodiments 9 to 16

[0223] It is basically the same as Example 1, except that the composite phase change layer 13 is different, specifically, the phase change material therein is filled in the pores of the thermal insulation substrate in the form of phase change microcapsules. The composition of the phase change material is the same as that of Example 1, and the main difference is that the wall material of the phase change microcapsule includes a polymer matrix and ceramic particles filled in the polymer matrix, the mass ratio of the polymer matrix to the ceramic particles, the mass ratio of the polymer matrix to the core material, and the Dv50 particle size parameters of the phase change microcapsules are shown in Table 2 below. Among them, the polymer matrix is ​​a phenolic resin matrix, the ceramic particles are silica particles with a Dv50 of 0.5μm, and the mass content of the phase change microcapsules in the phase change material layer is 60%.

[0224] The thermal insulation pads prepared in Examples 9 to 16 were subjected to a pressure resistance test, and the test method is as follows: a press is used to compress the thermal insulation pad at a compression rate of 2 mm / min. As the press is compressed, the greater the compression rate of the thermal insulation pad, the greater the stress on the thermal insulation pad. When the compression rate reaches a certain value, the packaging layer in the thermal insulation pad breaks, and the stress on the thermal insulation pad decreases rapidly. The inflection point where the stress decreases rapidly corresponds to the external pressure applied, which can reflect the pressure resistance of the thermal insulation pad. The test results are shown in Table 2.

[0225] Table 2

[0226]

[0227] Embodiment 17

[0228] It is basically the same as Example 1, and the only difference is that the composition of the phase change material layer in the composite phase change layer is different; specifically, the phase change material layer 131 includes a thermal insulation substrate and a phase change material filled in the pores of the thermal insulation substrate, and the thermal insulation substrate is also silica nano-ceramic fiber felt. The main difference is that the phase change material is replaced by an equal mass of silica sol.

[0229] The following is a compression performance test.

[0230] The single composite phase change layer in Example 1 was used as a sample (sample area was 100 mm*100 mm), and a stress-strain test was performed to obtain a compressive stress-strain curve, as shown in FIG. Fig.15As shown, it can be seen that the average strain of the sample when subjected to a stress of 0.5~5MPa, further 0.5~4MPa is in the range of 8%~20%, further about 10%~16%. The package failure rupture pressure of the package thermal conductive layer is slightly greater than 4MPa.

[0231] The first thermal insulation layer (silicon dioxide aerogel ceramic felt) in Example 1 was used as a sample (sample area was 100 mm*100 mm) to perform stress-strain test and obtain a compressive stress-strain curve, as shown in FIG. Fig.16 As shown. It can be seen that the strain of the sample is 25% to 70% when the stress is 0.5 to 5 MPa, further that the strain of the sample is 25% to 70% when the stress is 0.5 to 3 MPa, and further that the strain of the sample is 29% to 57% when the stress is 0.5 to 2.8 MPa.

[0232] The thermal insulation pad in Example 1 is used as a sample (the sample area is 100 mm*100 mm), and multiple groups of parallel stress-strain tests are performed to obtain a compressive stress-strain curve, as shown in FIG. Fig.17 As shown. It can be seen that the strain of the thermal insulation pad as a whole is 15% to 35% when the stress is 0.5 to 4 MPa, and further the strain is 15% to 35% when the stress is 0.5 to 3 MPa, and further 15% to 30%.

[0233] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0234] The above-described embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be construed as limiting the scope of the patent application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent application shall be subject to the attached claims.

Claims

1. A thermal insulation pad, characterized in that: include: A thermal insulation pad body, the thermal insulation pad body comprising an outer thermal insulation layer; and A strain detection component, arranged on the thermal insulation pad body; The strain detection component is located inside the outer thermal insulation layer or on the outer surface of the outer thermal insulation layer; the strain detection component is arranged on the outer surface of the outer thermal insulation layer, and the thermal insulation pad also includes a waterproof protective film, which is arranged on the outer surface of the strain detection component.

2. The thermal insulation pad according to claim 1, characterized in that: The strain detection component has an external wire, and the external wire is led out from one side of the outer heat insulation layer.

3. The thermal insulation pad according to claim 1, characterized in that: The thermal insulation pad meets at least one of the following conditions: (1) The ratio of the thickness of the strain detection member to the thickness of the outer heat insulation layer is 1:(500-10); (2) The thickness of the strain detection member is 10 μm to 50 μm; (3) The thickness of the outer insulation layer is 0.5 mm to 8 mm; (4) The outer thermal insulation layer meets the following conditions: thermal conductivity at 25°C ≤ 0.020 W / m·K, thermal conductivity at 200°C ≤ 0.027 W / m·K, thermal conductivity at 300°C ≤ 0.035 W / m·K, and thermal conductivity at 500°C ≤ 0.080 W / m·K; (5) The density of the outer insulation layer is 0.2 to 0.22 g / cm 3 ; (6) The outer thermal insulation layer includes at least one of thermal insulation felt and thermal insulation coating; (7) The outer heat insulation layer is a ceramic material layer; (8) The strain of the outer heat insulation layer when subjected to a stress of 0.5 to 5 MPa is 25% to 70%; (9) The thermal insulation pad also includes a release adhesive layer, and the release adhesive layer includes an adhesive layer and a release film. The adhesive layer is arranged on the outer surface of the outer thermal insulation layer, and the release film is arranged on the outer surface of the adhesive layer.

4. The thermal insulation pad according to claim 1, characterized in that: The thermal insulation pad body also includes a composite phase change layer, which includes a phase change material layer and a packaging layer. The packaging layer is arranged on the outer peripheral side of the phase change material layer; the outer thermal insulation layer is arranged on at least one side of the composite phase change layer.

5. The thermal insulation pad according to claim 4, characterized in that: The strain detection member has a first surface away from the composite phase change layer, the outer heat insulation layer has a second surface away from the composite phase change layer, and the distance between the first surface and the second surface is ≥0.3 mm.

6. The thermal insulation pad according to claim 5, characterized in that: The distance between the first surface and the second surface is 0.3 mm to 0.5 mm.

7. The thermal insulation pad according to claim 4, characterized in that: The thermal insulation pad meets at least one of the following conditions: (1) The thickness of the encapsulation layer is 0.1 mm to 0.3 mm; (2) The thickness of the composite phase change layer is 1 mm to 6 mm; (3) The thickness of the phase change material layer accounts for 70% to 96% of the total thickness of the composite phase change layer; (4) The thickness ratio of the composite phase change layer to the outer heat insulation layer is (0.15-12):1; (5) The encapsulation layer is an aluminum-plastic film or a polymer encapsulation film; (6) The thermal insulation pad further includes an adhesive layer, and the outer thermal insulation layer and the packaging layer are connected via the adhesive layer; (7) The outer heat insulation layer is disposed on at least one of the two sides in the thickness direction of the composite phase change layer; (8) The length and width of the outer heat insulation layer are respectively adapted to the length and width of the composite phase change layer; or at least one of the length and width of the outer heat insulation layer is greater than the corresponding length or width of the composite phase change layer; (9) The strain of the composite phase change layer is 8% to 20% when subjected to a stress of 0.5 to 5 MPa.

8. The thermal insulation pad according to any one of claims 4 to 7, characterized in that: The outer heat insulation layer includes a first heat insulation layer and a second heat insulation layer; The first heat insulation layer and the second heat insulation layer are respectively arranged on both sides of the composite phase change layer in a thickness direction, so that the composite phase change layer is sandwiched between the first heat insulation layer and the second heat insulation layer.

9. The thermal insulation pad according to claim 8, characterized in that: The edges of the first heat-insulating layer and the second heat-insulating layer are connected to each other to form an assembly cavity, and the composite phase-change layer is located in the assembly cavity.

10. The thermal insulation pad according to claim 9, characterized in that: An edge of at least one side surface of at least one of the first heat-insulating layer and the second heat-insulating layer forms a convex portion, and the convex portion encloses and forms at least a portion of the assembly cavity.

11. The thermal insulation pad according to claim 8, characterized in that: The packaging layer has a packaging margin portion, and the packaging margin portion is folded and located in the assembly cavity.

12. The thermal insulation pad according to claim 8, characterized in that: The thermal insulation pad also includes a first sealing frame and a second sealing frame. The first sealing frame is arranged on one side of the first thermal insulation layer, and the second sealing frame is arranged on one side of the second thermal insulation layer. The first sealing frame and the second sealing frame cooperate to fix the first thermal insulation layer, the composite phase change layer and the second thermal insulation layer.

13. The thermal insulation pad according to claim 12, characterized in that: The packaging layer has a packaging margin portion, and the packaging margin portion is located between the first sealing frame and the second sealing frame.

14. The thermal insulation pad according to claim 13, characterized in that: The first sealing frame has a first limiting groove, the second sealing frame has a second limiting groove, and the first thermal insulation layer, the composite phase change layer and the second thermal insulation layer are limited in a limiting space formed by the first limiting groove and the second limiting groove.

15. The thermal insulation pad according to claim 12, characterized in that: The outer surface of the first heat insulation layer is flush with the outer surface of the first sealing frame, and / or the outer surface of the second heat insulation layer is flush with the outer surface of the second sealing frame.

16. The thermal insulation pad according to claim 8, characterized in that: The thermal insulation pad meets at least one of the following conditions: (1) The strain of the thermal insulation pad when subjected to a stress of 0.5 to 4 MPa is 15% to 35%; (2) The thermal insulation pad also includes a third thermal insulation layer, and the composite phase change layer is also provided between the second thermal insulation layer and the third thermal insulation layer.

17. The thermal insulation pad according to any one of claims 4 to 7, characterized in that: The phase change material layer includes a heat insulation substrate and a phase change material; Wherein, the phase change material is filled in the thermal insulation substrate.

18. The thermal insulation pad according to claim 17, characterized in that: The phase change material is filled in the pores of the thermal insulation substrate in the form of phase change microcapsules; the phase change microcapsules include a core material and a wall material, the wall material is wrapped around the outer surface of the core material, and the core material includes the phase change material.

19. A battery, characterized in that: Comprising the thermal insulation pad as described in any one of claims 1 to 18.

20. The battery according to claim 19, characterized in that It also includes a plurality of battery cells, and the thermal insulation pad is arranged between at least two adjacent battery cells.

21. The battery according to claim 20, characterized in that The heat insulation pad is arranged between the large surfaces of two adjacent battery cells.

22. An electrical device, characterized in that: Comprising a battery as claimed in any one of claims 19 to 21.

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