Battery cell heat insulation pad and battery pack

Abstract

The invention relates to the technical field of energy storage, and discloses a battery cell heat insulation pad and a battery pack. The battery cell heat insulation pad comprises a first attaching film layer, a second attaching film layer and a first core material layer, the first attaching film layer comprises a first packaging part and a first peripheral part surrounding the first packaging part. The second attaching film layer comprises a second packaging part and a second peripheral part surrounding the second packaging part, a containing cavity is formed between the second packaging part and the first packaging part, and the second peripheral part is connected with the first peripheral part. The first core material layer is arranged in the containing cavity. The first core material layer comprises a first heat insulation part and a second heat insulation part surrounding the first heat insulation part, the minimum thickness of the first heat insulation part is t1, and the maximum heat conductivity coefficient of the first heat insulation part in the thickness direction is lambda1. The thickness of the second heat insulation part is t2, and the heat conductivity coefficient of the second heat insulation part in the thickness direction is lambda2. According to the battery cell heat insulation pad and the battery pack provided by the invention, the heat insulation performance of the battery cell heat insulation pad can be improved.

Description

Technical Field

[0001] The present application relates to the field of energy storage technology, and in particular to a battery cell thermal insulation pad and a battery pack. Background Art

[0002] With the continuous development of energy storage technology, energy storage equipment is being used more and more widely. Energy storage equipment can store the electrical energy output by the power generation device, and at the same time, it can output the stored electrical energy to the electrical equipment. Energy storage equipment uses battery cells as the basic unit for storing electrical energy, and the battery cells can be connected in series or in parallel to form a battery module. Since the battery module generates heat during operation, in order to avoid the concentrated heat affecting the performance of the battery cell, a battery cell insulation pad will be set in the battery module.

[0003] The battery cell thermal insulation pad has the function of preventing heat transfer, which can prevent different battery cells from affecting each other, thereby avoiding heat concentration and cascading thermal runaway. The thermal insulation performance of the battery cell thermal insulation pad affects the performance of the battery cell. How to design the structure of the battery cell thermal insulation pad to improve its thermal insulation performance is an important issue. Summary of the invention

[0004] The purpose of the embodiments of the present application is to provide a battery cell thermal insulation pad and a battery pack, which can be beneficial to improving the thermal insulation performance of the battery cell thermal insulation pad.

[0005] In order to solve the above technical problems, the embodiments of the present application provide a battery cell thermal insulation pad. The battery cell thermal insulation pad is used to be attached to the surface of the battery cell for thermal insulation. The battery cell thermal insulation pad includes a first attached film layer, a second attached film layer and a first core material layer. The first attached film layer includes a first packaging portion and a first peripheral portion surrounding the first packaging portion. The second attached film layer includes a second packaging portion and a second peripheral portion surrounding the second packaging portion, and a receiving cavity is formed between the second packaging portion and the first packaging portion, and the second peripheral portion is connected to the first peripheral portion. The first core material layer is arranged in the receiving cavity. The first core material layer includes a first thermal insulation portion and a second thermal insulation portion surrounding the first thermal insulation portion, the minimum thickness of the first thermal insulation portion is t1, and the maximum thermal conductivity of the first thermal insulation portion in the thickness direction is λ1. The thickness of the second thermal insulation portion is t2, and the thermal conductivity of the second thermal insulation portion in the thickness direction is λ2, t1 is greater than t2 and / or λ1 is less than λ2.

[0006] The embodiment of the present application also provides a battery pack. The battery pack includes a box, a battery module and the above-mentioned battery cell thermal insulation pad. The box has a receiving cavity. The battery module is arranged in the receiving cavity, and the battery module includes a plurality of battery cells arranged in the same direction, and two end plates clamping the plurality of battery cells in the middle. The battery cell thermal insulation pad is arranged between two adjacent battery cells or between the battery cell and the end plate.

[0007] The battery cell thermal insulation pad and battery pack provided by the embodiment of the present application form a containing area between the first packaging film and the second packaging film of the battery cell thermal insulation pad, and the first core material layer that plays a role of thermal insulation is placed in the containing area. The second thermal insulation part of the first core material layer is arranged around the first thermal insulation part located in the middle area, and by making the minimum thickness t1 of the first thermal insulation part greater than the thickness t2 of the second thermal insulation part, or making the maximum thermal conductivity λ1 of the first thermal insulation part in the thickness direction less than the thermal conductivity λ2 of the second thermal insulation part in the thickness direction, or making the minimum thickness t1 of the first thermal insulation part greater than the thickness t2 of the second thermal insulation part, and the maximum thermal conductivity λ1 of the first thermal insulation part in the thickness direction less than the thermal conductivity λ2 of the second thermal insulation part in the thickness direction, the battery cell thermal insulation pad can form a thermal insulation property in which the thermal insulation performance increases from the edge area to the middle area. This adapts to the temperature distribution characteristics of the battery cell surface, so as to improve the thermal insulation performance of the battery cell thermal insulation pad and reduce costs.

[0008] In some embodiments, the first thermal insulation portion includes a first portion and a second portion surrounding the first portion, the second portion is connected to the second thermal insulation portion away from the edge of the first portion, the thickness of the first portion is ta, the thermal conductivity of the first portion in the thickness direction is λa, the thickness of the second portion is tb, the thermal conductivity of the second portion in the thickness direction is λb, ta is greater than tb and / or λa is less than λb. In this way, by forming the first portion and the second portion with different thermal insulation properties, a gradient distribution of thermal insulation properties of more than two levels can be formed in the thermal insulation core material of the battery cell thermal insulation pad, which is conducive to giving full play to the thermal insulation effect in different areas.

[0009] In some embodiments, the ratio between ta and tb is 1.1 to 1.5, and the ratio between tb and t2 is 1.3 to 1.7. In this way, the thermal insulation effect of different parts can be precisely controlled by controlling the ratio of the thickness between different parts to meet the thermal insulation requirements of different areas on the surface of the battery cell.

[0010] In some embodiments, the area of ​​the first portion is S1, the area of ​​the second portion is S2, the area of ​​the second heat insulating portion is S3, the ratio between S1 and S2 is 0.11 to 0.20, and the ratio between S2 and S3 is 1.1 to 2.0. In this way, by controlling the area of ​​different parts of the heat insulating core material, it is possible to correspond to areas with different temperature distribution gradients on the surface of the battery cell and adapt to the temperature of different areas on the surface of the battery cell.

[0011] In some embodiments, the battery cell thermal insulation pad also includes a second core material layer, the second core material layer is attached to the side of the first core material layer close to the first attached film layer, the second core material layer includes a third thermal insulation part and a fourth thermal insulation part surrounding the third thermal insulation part, the thickness of the third thermal insulation part is t3, the thermal conductivity of the third thermal insulation part in the thickness direction is λ3, the thickness of the fourth thermal insulation part is t4, the thermal conductivity of the fourth thermal insulation part in the thickness direction is λ4, t3 is greater than t4 and / or λ3 is less than λ4. In this way, the composite thermal insulation core material can be formed by combining the second core material layer with the first core material layer, and the thermal insulation performance of the thermal insulation core material as a whole can be effectively improved.

[0012] In some embodiments, the battery cell thermal insulation pad further includes a third core material layer, the third core material layer is attached to the side of the second core material layer away from the first core material layer, the third core material layer includes a fifth thermal insulation portion and a sixth thermal insulation portion surrounding the fifth thermal insulation portion, the thickness of the fifth thermal insulation portion is t5, the thermal conductivity of the fifth thermal insulation portion in the thickness direction is λ5, the thickness of the sixth thermal insulation portion is t6, the thermal conductivity of the sixth thermal insulation portion in the thickness direction is λ6, t5 is greater than t6 and / or λ5 is less than λ6. In this way, a thermal insulation core material with a three-layer sandwich structure can be formed by setting a third core material layer, which is conducive to forming a thermal insulation structure with a relatively uniform change in thermal insulation performance from the edge area to the middle area, and adapting to the thermal insulation requirements of the gradual temperature change on the surface of the battery cell.

[0013] In some embodiments, the projection of the third insulation portion toward the first core material layer is located within the edge of the first insulation portion, and the projection of the fifth insulation portion toward the second core material layer is located within the edge of the third insulation portion. In this way, by controlling the distribution area of ​​the insulation portions of different core material layers, the change in the insulation performance of the insulation core material of the sandwich structure can be relatively gentle, effectively improving the overall insulation performance while meeting the insulation requirements of different areas on the surface of the battery cell.

[0014] In some embodiments, the battery cell thermal insulation pad further includes a first adhesive layer and a second adhesive layer, the first adhesive layer is attached to a side of the first attached film layer away from the second attached film layer, the second adhesive layer is attached to a side of the second attached film layer away from the first attached film layer, a first release paper is provided on a side of the first adhesive layer away from the first attached film layer, and a second release paper is provided on a side of the second adhesive layer away from the second attached film layer. In this way, the battery cell thermal insulation pad can be conveniently bonded to the surface of the battery cell by providing the adhesive layer.

[0015] In some embodiments, the battery cell thermal insulation pad further includes a buffer, which is disposed between the first attachment film layer and the first adhesive layer, and the projection of the buffer on the first attachment film layer is disposed around the first packaging portion. In this way, the buffer can play a buffering role and protect the thermal insulation core material.

[0016] In some embodiments, the buffer is provided with a plurality of through holes, and the plurality of through holes are arranged around the center of the buffer. In this way, by providing through holes on the buffer, space can be provided for deformation and contraction, which is beneficial to protecting the heat insulation core material.

[0017] In some embodiments, the buffer is provided with ribs, which are protruded from the edge of the buffer toward the direction away from the center. In this way, the surface of the battery cell can be effectively isolated by the ribs to protect the blue film on the surface of the battery cell.

[0018] In some embodiments, the first core material layer, the second core material layer and the third core material layer are sewn together by weaving threads, so that the structural stability of the different core material layers when they are combined can be ensured by sewing.

[0019] In some embodiments, t1 is greater than or equal to 1.5 mm and less than or equal to 5 mm, and λ1 is greater than or equal to 0.01 W / m·K and less than or equal to 0.08 W / m·K. In this way, by controlling the thickness of the first thermal insulation part and the maximum thermal conductivity of the first thermal insulation part in the thickness direction, it is possible to ensure that the first thermal insulation part fully exerts the thermal insulation performance of the material itself while saving materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] One or more embodiments are exemplarily described by pictures in the corresponding drawings, and these exemplified descriptions do not constitute limitations on the embodiments. Elements with the same reference numerals in the drawings represent similar elements, and unless otherwise stated, the figures in the drawings do not constitute proportional limitations.

[0021] Figure 1 It is a schematic diagram of the three-dimensional structure of a battery cell thermal insulation pad provided in some embodiments of the present application; Figure 2 It is a schematic diagram of the exploded structure of the battery cell thermal insulation pad provided in some embodiments of the present application; Figure 3 It is a schematic diagram of the main structure of the first core material layer in the battery core thermal insulation pad provided in some embodiments of the present application; Figure 4 It is a schematic diagram of a top view of the structure of the first core material layer in the battery core thermal insulation pad provided in some embodiments of the present application; Figure 5 It is a schematic diagram of a top view of the structure of the first core material layer in the battery core thermal insulation pad provided in other embodiments of the present application; Figure 6 It is a schematic diagram of the exploded structure of the battery cell thermal insulation pad provided in other embodiments of the present application; Figure 7 It is a schematic diagram of the main structure of the second core material layer in the battery core thermal insulation pad provided in other embodiments of the present application; Figure 8It is a schematic diagram of a top view of the structure of the second core material layer in the battery core thermal insulation pad provided in other embodiments of the present application; Fig. 9 It is a schematic diagram of the exploded structure of the battery cell thermal insulation pad provided in some other embodiments of the present application; Fig.10 It is a schematic diagram of the main structure of the third core material layer in the battery core thermal insulation pad provided in some other embodiments of the present application; Fig.11 is a schematic diagram of a top view of the structure of a third core material layer in a battery core thermal insulation pad provided in some other embodiments of the present application; Fig.12 It is a schematic diagram of the separation structure of the thermal insulation core material in the battery core thermal insulation pad provided in some other embodiments of the present application; Fig.13 It is a schematic diagram of the three-dimensional structure of a buffer member in a battery cell thermal insulation pad provided in some embodiments of the present application; Fig.14 It is a schematic diagram of the force deformation of a local position of a buffer member in a battery cell thermal insulation pad provided in some embodiments of the present application; Fig.15 It is a schematic diagram of the main structure of a battery cell in the prior art. DETAILED DESCRIPTION

[0022] To make the purpose, technical scheme and advantages of the embodiments of the present application clearer, each embodiment of the present application will be described in detail below in conjunction with the accompanying drawings. However, it will be appreciated by those skilled in the art that in each embodiment of the present application, many technical details are proposed in order to enable the reader to better understand the present application. However, even without these technical details and various changes and modifications based on the following embodiments, the technical scheme claimed in the present application can also be implemented. The division of the following embodiments is for the convenience of description, and the specific implementation of the present application should not constitute any limitation, and the various embodiments can be combined with each other and referenced to each other without contradiction.

[0023] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by technicians in the technical field to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" in the specification and claims of this application and the above-mentioned figure descriptions and any variations thereof are intended to cover non-exclusive inclusions.

[0024] In the description of the embodiments of the present application, unless otherwise clearly specified and limited, technical terms such as "installed", "connected", "connected" and the like should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, and it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the embodiments of the present application can be understood according to the specific circumstances.

[0025] With the continuous development of new energy technology, the proportion of new energy in social life and production is also increasing. The application of energy storage equipment is also increasing. In actual situations, energy storage equipment can adopt cabin-level energy storage, cluster-level energy storage and pack-level energy storage according to different application scenarios. Battery cells, that is, single batteries, are widely used in different types of energy storage equipment as efficient energy storage components. Multiple battery cells can form a battery module by connecting in series or in parallel, and the battery module adopts a certain packaging form to form a whole. One or more battery modules can be used in energy storage equipment, and a certain number of battery modules can form a battery cluster for unified management and control. Multiple battery modules can be packaged in a box of a certain volume to form a battery pack, or they can be packaged in a larger container to form a container energy storage system. Multiple battery modules can be jointly managed and controlled through a battery management system and a thermal management system.

[0026] During the charging and discharging process, chemical reactions will occur inside the battery cell, generating a large amount of heat energy, causing the temperature of the battery module to rise. In particular, as the capacity of the battery cell becomes larger and the energy density becomes higher, the heat generated by the battery cell during operation is also increasing. In order to ensure that heat is not concentrated between the battery cells due to heat transfer, a battery cell insulation pad is usually set on the surface of the battery cell in the battery module to prevent the thermal diffusion process of the battery cell. The battery cell insulation pad contains an insulation core material made of a material with a low thermal conductivity, which has a good thermal insulation effect and flame retardant properties. The battery cell insulation pad can be set between two adjacent battery cells in the middle position, or on the surface of the battery cell in the outermost position facing the box body to cut off the heat transfer path from the battery cell to the surrounding area. In addition, when thermal runaway occurs in some battery cells, the battery cell insulation pad can play a flame retardant role to prevent the thermal runaway of the battery cell from spreading and causing a chain of thermal runaway of other battery cells.

[0027] However, currently, the thermal insulation pads for battery cells usually have thermal insulation core materials with the same thickness and material on the entire surface, and the thickness of the thermal insulation core materials needs to be designed according to the maximum temperature, which easily leads to high material costs. In addition, the thermal insulation core materials are not designed according to the heating characteristics of the battery cells themselves, resulting in poor thermal insulation efficiency and low material utilization of the thermal insulation pads for battery cells.

[0028] In order to improve the thermal insulation performance of the battery cell thermal insulation pad, some embodiments of the present application provide a battery cell thermal insulation pad. The battery cell thermal insulation pad optimizes the thermal insulation core material based on the temperature gradient distribution of the battery cell's own heat, that is, the temperature gradually changes from the middle area to the edge area, so that the thermal insulation performance of the battery cell thermal insulation pad is gradient distributed. Thereby, the battery cell thermal insulation pad forms a gradient thermal insulation performance, enhances thermal safety, and improves thermal insulation efficiency. It can make the battery cell thermal insulation pad more adaptable to complex working conditions and increase product service life. The gradient arrangement of the thermal insulation performance of the battery cell thermal insulation pad can give full play to the characteristics and advantages of the material and reduce costs.

[0029] It should be noted that when the battery module is working, the temperature in the middle area of ​​the cell surface is the highest, and gradually diffuses outward, presenting a temperature gradient that gradually decreases from the middle area to the edge area. In addition, there is a certain gap in the temperature distribution between different areas, forming a middle area with a higher temperature and an edge area with a lower temperature. Some areas also have a temperature gradient phenomenon. By providing an insulating core material with variable thickness or material, or an insulating core material with varying thickness and material in the cell thermal insulation pad, the cell thermal insulation pad can form an insulation characteristic that corresponds to the temperature characteristic of the gradient distribution on the cell surface and presents a gradient distribution. The thermal insulation performance of the thermal insulation core material increases from the edge area to the middle area, which can fully exert the thermal insulation performance of the thermal insulation core material in different areas while meeting the thermal insulation requirements.

[0030] Combine the following Figures 1 to 14 The structure of the battery cell thermal insulation pad provided in some embodiments of the present application is described. The battery cell thermal insulation pad is used to be attached to the surface of the battery cell for thermal insulation.

[0031] like Figures 1 to 14 As shown, the battery cell thermal insulation pad provided in some embodiments of the present application includes a first attached film layer 11, a second attached film layer 12 and a first core material layer 13. The first attached film layer 11 includes a first packaging portion 111 and a first peripheral portion 112 surrounding the first packaging portion 111. The second attached film layer 12 includes a second packaging portion 121 and a second peripheral portion 122 surrounding the second packaging portion 121. A receiving cavity is formed between the second packaging portion 121 and the first packaging portion 111, and the second peripheral portion 122 is connected to the first peripheral portion 112. The first core material layer 13 is arranged in the receiving cavity. The first core material layer 13 includes a first thermal insulation portion 131 and a second thermal insulation portion 132 surrounding the first thermal insulation portion 131. The minimum thickness of the first thermal insulation portion 131 is t1, and the maximum thermal conductivity of the first thermal insulation portion 131 in the thickness direction is λ1. The thickness of the second heat insulating portion 132 is t2, the thermal conductivity of the second heat insulating portion 132 in the thickness direction is λ2, t1 is greater than t2 and / or λ1 is less than λ2.

[0032] The attachment film layer is the outer packaging part of the battery cell thermal insulation pad. The attachment film layer can be fixedly connected to the surface of the battery cell. For example, it can be fixed on the surface of the battery cell by whole-surface pasting or partial pasting, or it can be fixed on the surface of the battery cell by magnetic attraction or binding. The attachment film layer includes a first attachment film layer 11 and a second attachment film layer 12 arranged opposite to each other, and a receiving cavity for accommodating the thermal insulation core material is formed between the two attachment film layers, which can be used to encapsulate the thermal insulation core material. The encapsulation portion of each attachment film layer corresponds to the encapsulation area of ​​the thermal insulation core material, and the peripheral portion corresponds to the connection area of ​​the two attachment film layers. The peripheral portions of the two attachment film layers can be formed into one by hot pressing, or by bonding, or by suturing. For example, the attachment film layer can be made of hot melt film so as to be formed into one by hot pressing. The hot melt film can be provided with a recessed cavity, and different hot melt films can be pressed and combined by hot pressing to leave burrs around. After pressing, the thermal insulation core material is wrapped inside, and the thermal insulation core material is tightly and completely attached to the surface of the hot melt film.

[0033] The first core material layer 13 forms the thermal insulation core material of the battery core thermal insulation pad, and is made of a material with a low thermal conductivity, which can better isolate the transfer of heat and block the heat transfer path. The first core material layer 13 includes different thermal insulation parts, and different thermal insulation parts can be made of materials of the same thermal insulation material with different thicknesses, or made of materials of different thermal insulation materials with the same thickness, or made of thermal insulation materials with different thicknesses and different materials. Different thermal insulation properties are formed in different areas of the battery core thermal insulation pad. Since the thermal resistance is proportional to the thickness and inversely proportional to the thermal conductivity, by making the minimum thickness t1 of the first thermal insulation part 131 greater than the thickness t2 of the second thermal insulation part 132, and / or the maximum thermal conductivity λ1 of the first thermal insulation part 131 in the thickness direction is less than the thermal conductivity λ2 of the second thermal insulation part 132 in the thickness direction, the thermal insulation performance of the first thermal insulation part 131 located in the middle area can be higher than the thermal insulation performance of the second thermal insulation part 132 located in the edge area, which can meet the thermal insulation requirements of areas with different temperature gradients on the surface of the battery core. Thermal conductivity refers to the amount of heat transferred through an area of ​​1 square meter in 1 second under stable heat transfer conditions when the temperature difference between the two surfaces of a 1 meter thick material is 1 degree. Thermal conductivity can be used to characterize thermal conductivity and reflect thermal insulation properties. The unit of thermal conductivity is W / m·K, that is, watt / meter·degree.

[0034] The first insulation part 131 is located in the middle area of ​​the first core material layer 13 and contacts the middle area of ​​the battery cell surface. The second insulation part 132 is located in the edge area of ​​the first core material layer 13 and contacts the edge area of ​​the battery cell surface. The middle area is the area formed by spreading outward from the center point to a certain range, and the edge area is the other area outside the center area and surrounding the center area. Different insulation parts of the first core material layer 13 can have insulation effects corresponding to different areas of the battery cell surface. In actual situations, the first core material layer 13 and the battery cell insulation pad can have outer contours of different shapes. If the first core material layer 13 and the battery cell insulation pad have a rectangular outer contour, the center point of the first core material layer 13 is located at the intersection of two diagonals. If the first core material layer 13 and the battery cell insulation pad are circular structures, the center point of the first core material layer 13 is located at the center of the circle. If the first core material layer 13 and the battery cell insulation pad are irregular shapes, the center point position can be determined according to the shape center of the first core material layer 13. In addition, the outer contour shape of the first core material layer 13 and the outer contour shape of the battery core thermal insulation pad can be consistent or set in different forms.

[0035] In the battery cell thermal insulation pad provided in some embodiments of the present application, a containing area is formed between the first packaging film and the second packaging film, and the first core material layer 13 having a heat insulation effect is placed in the containing area. The second heat insulation part 132 of the first core material layer 13 is arranged around the first heat insulation part 131 located in the middle area, and by making the minimum thickness t1 of the first heat insulation part 131 greater than the thickness t2 of the second heat insulation part 132, or making the maximum thermal conductivity λ1 of the first heat insulation part 131 in the thickness direction less than the thermal conductivity λ2 of the second heat insulation part 132 in the thickness direction, or making the minimum thickness t1 of the first heat insulation part 131 greater than the thickness t2 of the second heat insulation part 132, and the maximum thermal conductivity λ1 of the first heat insulation part 131 in the thickness direction less than the thermal conductivity λ2 of the second heat insulation part 132 in the thickness direction, the battery cell thermal insulation pad can form a heat insulation characteristic in which the heat insulation performance increases from the edge area to the middle area. This adapts to the temperature distribution characteristics of the battery cell surface, improves the heat insulation performance of the battery cell thermal insulation pad, and reduces costs.

[0036] In some embodiments, the first thermal insulation portion 131 may include a first portion 1311 and a second portion 1312 surrounding the first portion 1311, the second portion 1312 is connected to the second thermal insulation portion 132 away from the edge of the first portion 1311, the thickness of the first portion 1311 is ta, the thermal conductivity of the first portion 1311 in the thickness direction is λa, the thickness of the second portion 1312 is tb, the thermal conductivity of the second portion 1312 in the thickness direction is λb, ta is greater than tb and / or λa is less than λb.

[0037] The first part 1311 is located in the middle area of ​​the first thermal insulation part 131, the second part 1312 is located in the edge area of ​​the first thermal insulation part 131, and the second part 1312 is connected to the second thermal insulation part 132. In other words, the first core material layer 13 can be set to form a three-level gradient distribution characteristic of thermal insulation performance from the middle area to the edge area. The first part 1311 and the second part 1312 are located in different areas of the first thermal insulation part 131 of the first core material layer 13, and the first part 1311, the second part 1312 and the second thermal insulation part 132 form a three-level gradient distribution of thermal insulation characteristics. The thickness ta of the first part 1311 is greater than the thickness tb of the second part 1312, or the thermal conductivity λa of the first part 1311 in the thickness direction is less than the thermal conductivity λb of the second part 1312 in the thickness direction, or the thickness ta of the first part 1311 is greater than the thickness tb of the second part 1312 and the thermal conductivity λa of the first part 1311 in the thickness direction is less than the thermal conductivity λb of the second part 1312 in the thickness direction, so that the thermal insulation performance of the first part 1311 is higher than the thermal insulation performance of the second part 1312. As a result, the first core material layer 13 forms a gradient distribution characteristic of thermal insulation performance of more than two levels from the middle area to the edge area, making the thermal insulation performance of the first core material layer 13 more refined and more corresponding to the distribution characteristics of the temperature reduction from the middle area to the edge area of ​​the battery cell surface. In addition, it can also better adapt to the gradual temperature distribution characteristics of the battery cell surface, so that the thermal insulation performance of different areas of the battery cell thermal insulation pad corresponds more closely to the temperature characteristics of different areas of the battery cell surface. When the surface area of ​​the battery cell is large, the thermal insulation requirements of different areas on the surface of the battery cell can be met by forming a gradient distribution of thermal insulation performance with more than two levels.

[0038] In some embodiments, the thermal insulation core material is designed with different thicknesses. The thermal insulation core material is made of aerogel, which is coated inside the accommodation cavity formed by the hot melt film packaging. The upper hot melt film and the lower hot melt film are made of PET (PolyethyleneTerephthalate). The two are pressed together by hot pressing to leave burrs on all sides. After pressing, the thermal insulation core material is wrapped inside, and the thermal insulation core material is tightly and completely attached to the surface of the hot melt film. The thermal insulation core material can be composed of three types of aerogels with different thicknesses, and the thickness of the three types of aerogels decreases from the middle area to the edge area of ​​the thermal insulation core material. The thermal insulation core material is set to a rectangle as a whole, and different insulation parts are divided according to rectangles. According to the gradient characteristics of the heating temperature of the battery cell, the dimensional relationship between the thickness, length and width of the three types of aerogels is designed. L1, L2, L3 are the boundary length dimensions of the first part 1311, the second part 1312, and the second heat insulation part 132, respectively, in mm (millimeter); W1, W2, W3 are the boundary width dimensions of the first part 1311, the second part 1312, and the second heat insulation part 132, respectively, in mm. The dimensional relationship between the thickness, length, and width of the three aerogels can be: ta:tb:t2=4:3:2; L1:L2:L3=3:8:10; W1:W2:W3=2:6:7. Fig.15 The surface structure of the battery cell is shown schematically. The surface dimensions of the battery cell are as follows: Fig.15 As shown, Lc is the length dimension of the cell surface, and Wc is the width dimension of the cell surface. According to the gradient characteristics of the heating temperature of the cell, the thickness ta of the first part 1311 of the thermal insulation core material ranges from 1.5 mm to 5 mm; the boundary length dimension L3 of the second thermal insulation part 132 ranges from 0.92Lc to 0.95Lc; the boundary width dimension W3 of the second thermal insulation part 132 ranges from 0.9Wc to 0.97Wc.

[0039] In addition, when the thermal insulation core material has parts with different thicknesses, in order to ensure the consistency of the degree of adhesion in different areas when bonding with the battery cell, the attached film layer can be set to a concave arc structure. That is, the attached film layer can have a thickness distribution characteristic different from that of the thermal insulation core material to ensure the consistency of the thickness of the battery cell thermal insulation pad at all locations. In addition, the outer side of the attached film layer can also have a certain curvature to adapt to the expansion and deformation of the battery cell, reduce the extrusion force on the thermal insulation core material, and increase the service life of the thermal insulation core material.

[0040] In other embodiments, the thermal insulation core material is formed of three different materials, and the thermal insulation materials in different areas are respectively selected from nano-insulation pads, aerogels, and ceramic silicone foams. The three thermal insulation materials are set in the form of decreasing thermal conductivity from the edge area to the middle area in the thickness direction. According to the gradient distribution characteristics of the heating temperature of the battery core, the thickness dimensions of the three thermal insulation materials can be obtained by experiment according to the thermal conductivity of different materials. The thickness of the three thermal insulation materials can be reduced from the middle area to the edge area of ​​the thermal insulation core material, or remain consistent. The minimum thermal conductivity value range is 0.01W / m·K to 0.08W / m·K.

[0041] In actual situations, it is also possible to form a gradient distribution characteristic of thermal insulation performance of more than three levels from the middle area to the edge area of ​​the first core material layer 13 to adapt to the heat distribution characteristics of the battery cell surface. The gradient distribution characteristics of the thermal insulation performance of the first core material layer 13 from the middle area to the edge area can also be controlled within three levels to save the cost of the battery cell insulation pad. A lug portion can also be formed around the battery cell insulation pad, and the lug portion is provided in multiples, and multiple lug portions are provided around the center of the insulation core material. Thus, a convex structure arranged at intervals is formed on the periphery of the battery cell insulation pad. Each lug portion can be provided with a different tooth-shaped structure, such as a triangular or rectangular convex shape, or a trapezoidal convex shape. While contacting with the edge area of ​​the battery cell surface, the use of thermal insulation material in the edge area can be saved. And it can form a distribution characteristic in which the area of ​​the thermal insulation material in the edge area is smaller than the area of ​​the thermal insulation material in the middle area, which adapts to the insulation requirements of different areas on the battery cell surface. At the same time, the intervals between the lugs can also reserve space for the expansion of the battery cell surface, adapt to the expansion and deformation of the battery cell, and reduce the extrusion force on the battery cell insulation pad.

[0042] like Figure 5 As shown, the joints of different parts of the thermal insulation core material can be rounded to eliminate thermal stress mutations, and the thermal performance gradient change is closer to the heating characteristics of the battery core. The fillet radius at the junction of the first part 1311 and the second part 1312 can be controlled within the range of 2mm to 8mm, for example, 2mm, 4mm, 6mm or 8mm. The fillet radius at the junction of the second part 1312 and the second thermal insulation part 132 can be controlled within the range of 10mm to 30mm, for example, 10mm, 13mm, 16mm, 19mm, 20mm, 23mm, 26mm, 29mm or 30mm.

[0043] In addition, the ratio of the thickness ta of the first portion 1311 to the thickness tb of the second portion 1312 may be 1.1 to 1.5, and the ratio of the thickness tb of the second portion 1312 to the thickness t2 of the second heat insulating portion 132 may be 1.3 to 1.7.

[0044] By controlling the thickness of different parts, the thermal insulation performance of different parts can be optimized. The thermal resistance of the thermal insulation core material is proportional to the thickness, and the thickness of different parts of the thermal insulation core material increases step by step from the edge area to the middle area. The thickness ta of the first part 1311 located in the middle area is greater than the thickness tb of the second part 1312 located in the middle transition area, and the thickness of the second part 1312 located in the middle transition area is greater than the thickness t2 of the second thermal insulation part 132 located in the edge area.

[0045] The ratio between the thickness ta of the first part 1311 and the thickness tb of the second part 1312 can be controlled within the range of 1.1 to 1.5, such as 1.1, 1.2, 1.3, 1.4 or 1.5. The ratio between the thickness tb of the second part 1312 and the thickness t2 of the second insulation part 132 can be controlled within the range of 1.3 to 1.7, such as 1.3, 1.4, 1.5, 1.6 or 1.7. By controlling the thickness ratio between different parts of the first core material layer 13, it is possible to avoid the failure to fully utilize the material insulation properties of different areas of the first core material layer 13 due to a large difference in thickness, and it is also possible to avoid the failure to better adapt to the insulation requirements of different areas on the surface of the battery cell due to a small difference in thickness.

[0046] In some embodiments, the area of ​​the first part 1311 is S1, the area of ​​the second part 1312 is S2, the area of ​​the second thermal insulation part 132 is S3, the ratio of the area S1 of the first part 1311 to the area S2 of the second part 1312 is 0.11 to 0.20, and the ratio of the area S2 of the second part 1312 to the area S3 of the second thermal insulation part 132 is 1.1 to 2.0.

[0047] Different areas of the first core material layer 13 correspond to different areas on the surface of the battery cell. By controlling the area at different areas of the first core material layer 13, the coverage area of ​​the corresponding areas on the surface of the battery cell by different areas can be controlled. The areas with different thermal insulation properties of the battery cell thermal insulation pad fit the areas with different temperatures on the surface of the battery cell. By controlling the area of ​​the first part 1311 to be smaller than the area of ​​the second part 1312, the thermal insulation properties of the thermal insulation material of the first part 1311 can be fully utilized, so that the first part 1311 faces the middle area with higher temperature on the surface of the battery cell. By controlling the area of ​​the second part 1312 to be larger than the area of ​​the second thermal insulation part 132, the middle transition area of ​​the thermal insulation core material can form a sufficient area, which can effectively block the heat transfer path on the surface of the battery cell. By controlling the size of the area of ​​the second thermal insulation part 132, the edge area of ​​the thermal insulation core material can be formed into a smaller area, which can reduce the use of thermal insulation materials in the edge area while achieving a certain thermal insulation effect.

[0048] In practice, the ratio of the area S1 of the first portion 1311 to the area S2 of the second portion 1312 is in the range of 0.11 to 0.20, such as 0.11, 0.13, 0.15, 0.17, 0.19 or 0.20. The ratio of the area S2 of the second portion 1312 to the area S3 of the second insulation portion 132 is in the range of 1.1 to 2.0, such as 1.1, 1.3, 1.5, 1.7, 1.9 or 2.0.

[0049] like Figure 6 As shown, the battery cell thermal insulation pad may further include a second core material layer 14, which is attached to the side of the first core material layer 13 close to the first attachment film layer 11. The second core material layer 14 includes a third thermal insulation portion 141 and a fourth thermal insulation portion 142 surrounding the third thermal insulation portion 141, the thickness of the third thermal insulation portion 141 is t3, the thermal conductivity of the third thermal insulation portion 141 in the thickness direction is λ3, the thickness of the fourth thermal insulation portion 142 is t4, the thermal conductivity of the fourth thermal insulation portion 142 in the thickness direction is λ4, t3 is greater than t4 and / or λ3 is less than λ4.

[0050] The second core material layer 14 is made of the same material with low thermal conductivity as the first core material layer 13. The second core material layer 14 can be bonded with the first core material layer 13 to form a composite thermal insulation structure to enhance the thermal insulation performance of the core material layer. The second core material layer 14 includes multiple parts with different thicknesses and / or different thermal conductivities in the thickness direction, thereby forming differentiated thermal insulation performance in different areas of the second core material layer 14. The third thermal insulation portion 141 is located in the middle area of ​​the second core material layer 14, and the fourth thermal insulation portion 142 is located in the edge area of ​​the second core material layer 14. By making the thickness t3 of the third heat insulating part 141 greater than the thickness t4 of the fourth heat insulating part 142, or making the thermal conductivity λ3 of the third heat insulating part 141 in the thickness direction less than the thermal conductivity λ4 of the fourth heat insulating part 142 in the thickness direction, or making the thickness t3 of the third heat insulating part 141 greater than the thickness t4 of the fourth heat insulating part 142 and the thermal conductivity λ3 of the third heat insulating part 141 in the thickness direction less than the thermal conductivity λ4 of the fourth heat insulating part 142 in the thickness direction, the thermal insulation performance in the middle area of ​​the second core material layer 14 can be improved. Thus, the thermal insulation effect in the middle area of ​​the battery cell thermal insulation pad is enhanced, and the transfer of heat between different battery cells is effectively blocked.

[0051] like Fig. 9As shown, the battery cell thermal insulation pad may further include a third core material layer 15, and the third core material layer 15 is attached to the side of the second core material layer 14 away from the first core material layer 13. The third core material layer 15 includes a fifth thermal insulation portion 151 and a sixth thermal insulation portion 152 surrounding the fifth thermal insulation portion 151, the thickness of the fifth thermal insulation portion 151 is t5, and the thermal conductivity of the fifth thermal insulation portion 151 in the thickness direction is λ5, the thickness of the sixth thermal insulation portion 152 is t6, and the thermal conductivity of the sixth thermal insulation portion 152 in the thickness direction is λ6, t5 is greater than t6 and / or λ5 is less than λ6.

[0052] The third core material layer 15 and the first core material layer 13 are attached to both sides of the second core material layer 14, sandwiching the second core material layer 14 in the middle to form a three-layer sandwich structure. The thermal insulation effect of the battery cell thermal insulation pad can be effectively improved. The third core material layer 15 includes multiple parts with different thicknesses and / or different thermal conductivity coefficients in the thickness direction, thereby forming differentiated thermal insulation performance in different areas of the third core material layer 15. The fifth thermal insulation part 151 is located in the middle area of ​​the third core material layer 15, and the sixth thermal insulation part 152 is located in the edge area of ​​the third core material layer 15. By making the thickness t5 of the fifth heat insulating part 151 greater than the thickness t6 of the sixth heat insulating part 152, or making the thermal conductivity λ5 of the fifth heat insulating part 151 in the thickness direction less than the thermal conductivity λ6 of the sixth heat insulating part 152 in the thickness direction, or making the thickness t5 of the fifth heat insulating part 151 greater than the thickness t6 of the sixth heat insulating part 152 and the thermal conductivity λ5 of the fifth heat insulating part 151 in the thickness direction less than the thermal conductivity λ6 of the sixth heat insulating part 152 in the thickness direction, the thermal insulation performance in the middle area of ​​the third core material layer 15 can be improved. Thus, the thermal insulation effect in the middle area of ​​the battery cell thermal insulation pad is enhanced, and the transfer of heat between different battery cells is effectively blocked.

[0053] In actual situations, the combined thermal insulation core material can be composed of at least three or more core material layers, and the combined thermal insulation core material is staggered and stacked in at least three layers. The dimensions of the thickness, length, and width of the combined thermal insulation core material can be obtained through experimental design. In order to enable the multi-layer combined thermal insulation core material to achieve gradient-distributed thermal insulation performance, the thermal conductivity of each core material layer can be designed to form a multi-level gradient distribution from the middle area to the edge area. The multi-layer thermal insulation core material presents a multi-layer sandwich structure and is arranged inside the accommodating cavity formed by the attached film layer. The attached film layer can be hot-pressed and combined to leave burrs around it. After pressing, the combined thermal insulation core material is wrapped inside, and the thermal insulation core material is tightly and completely attached to the surface of the attached film layer.

[0054] In some embodiments, the projection of the third insulation part 141 toward the first core material layer 13 may be located within the edge of the first insulation part 131 , and the projection of the fifth insulation part 151 toward the second core material layer 14 may be located within the edge of the third insulation part 141 .

[0055] Different core material layers can be provided with different insulation parts in a gradient form, that is, the boundary lines of different insulation parts of multiple core material layers gradually move away from the center position or gradually approach the center position. This makes the overall insulation performance of the battery cell insulation pad change more evenly from the edge area to the middle area to meet the insulation requirements of the gradual change in the surface temperature of the battery cell. The core material layer with a larger area in the middle area can face the battery cell surface with a higher maximum temperature, and the core material layer with a smaller area in the middle area can face the battery cell surface with a lower maximum temperature.

[0056] In actual situations, the third core material layer 15 and the first core material layer 13 may also have the same gradient distribution characteristics of thermal insulation performance, that is, the distribution of different thermal insulation parts of the third core material layer 15 and the first core material layer 13 has a mirror relationship on both sides of the second core material layer 14, and is symmetrically attached to both sides of the second core material layer 14, so as to ensure the thermal insulation requirements between two battery cells with similar temperatures.

[0057] like Fig. 9 As shown, the battery cell thermal insulation pad may also include a first adhesive layer 16 and a second adhesive layer 17. The first adhesive layer 16 is attached to the side of the first attached film layer 11 away from the second attached film layer 12, and the second adhesive layer 17 is attached to the side of the second attached film layer 12 away from the first attached film layer 11. A first release paper 161 is provided on the side of the first adhesive layer 16 away from the first attached film layer 11, and a second release paper 171 is provided on the side of the second adhesive layer 17 away from the second attached film layer 12.

[0058] That is to say, the battery cell thermal insulation pad is provided with an adhesive layer for pasting and a release paper for protecting the adhesive layer on the outside of the attached film layer. The battery cell thermal insulation pad can be pasted to the surface of the battery through the adhesive layer. In actual situations, it is only necessary to tear off the release paper on the outermost side of the battery cell thermal insulation pad to achieve the bonding between the battery cell thermal insulation pad and the surface of the battery cell through the adhesive layer. The release paper is provided with an easy-to-tear portion protruding from the adhesive layer, i.e., a tearing ear, through which the release paper on both sides of the battery cell thermal insulation pad can be easily torn off to expose the adhesive layer. Then, it can be bonded to the surface of the battery cell through the adhesive layer.

[0059] like Fig. 9 As shown, the battery cell thermal insulation pad may further include a buffer 18 , which is disposed between the first attachment film layer 11 and the first adhesive layer 16 , and the projection of the buffer 18 on the first attachment film layer 11 is disposed around the first packaging portion 111 .

[0060] The buffer 18 has a deformation property and can play a buffering role in the battery core thermal insulation pad. The buffer 18 can be made of natural rubber, synthetic rubber or foam material, for example, the buffer 18 can be foam.

[0061] The buffer 18 can be a buffer frame or a buffer strip. The buffer strip can be placed around the thermal insulation core material. The buffer strip can rebound under a certain pressure and has good flame retardant properties. It can be used to absorb and release the expansion force generated during the charging and discharging of the battery cell. It plays a role in protecting the battery cell. At the same time, the buffer 18 can also protect the thermal insulation core material to prevent the thermal insulation core material from being damaged by the battery cell. The use of the buffer 18 is conducive to reducing the thickness of the thermal insulation core material and avoiding the need to use thicker thermal insulation core material to achieve the buffering effect. It is conducive to reducing costs.

[0062] In actual situations, the buffer 18 can be set only on both sides of the thermal insulation core material, which can reduce the impact on the thermal insulation area of ​​the thermal insulation core material while ensuring the buffering effect, and increase the effective area of ​​the thermal insulation core material, so that the thermal insulation and flame retardant area of ​​the battery cell thermal insulation pad is larger, effectively delaying the time of thermal runaway of the battery cell.

[0063] When the buffer member 18 is set as a circular frame, the position of the thermal insulation core material can also be restricted, so that the thermal insulation core material is firmly and reliably maintained in the accommodating cavity, and will not be squeezed out of the circular frame due to the expansion of the battery cell. Ensure the normal use of the thermal insulation core material. The circular frame can be made of silicone material, and the corner position can be set in a chamfered form. The buffer foam of the circular frame structure can be attached to the pressed edge of the hot melt film. The adhesive layer on the outside of the hot melt film uses double-sided tape, which is attached to the upper and lower hot melt films respectively. The release paper on the outside of the adhesive layer has tear ears, and the tear ears are arranged symmetrically to facilitate the operation of automated equipment.

[0064] In some embodiments, the buffer member 18 may be provided with a plurality of through holes 181 , and the plurality of through holes 181 are arranged around the center of the buffer member 18 .

[0065] The through holes 181 can be sequentially arranged along the extension direction of the buffer 18, and the through holes 181 are distributed at different positions of the buffer 18. The arrangement of the through holes 181 can provide space for the deformation and contraction of the buffer 18, which is beneficial to the deformation and contraction of the local position of the buffer 18, and ensures the overall buffering effect of the buffer 18.

[0066] like Fig.13 As shown, the buffer member 18 is configured as a circular frame structure, and holes are formed at different positions on the circular frame. Fig.14 As shown, following the principle of minimum resistance, the buffer member 18 shrinks and deforms toward the center of the hole during the compression process, thereby avoiding squeezing of the thermal insulation core material.

[0067] In addition, the buffer member 18 may be provided with ribs 182 , and the ribs 182 are provided to protrude from the edge of the buffer member 18 in a direction away from the center.

[0068] The ribs 182 can be arranged at one side edge or both sides edge of the buffer 18, or at the edges around the buffer 18. The ribs 182 extend the isolation area of ​​the buffer 18 and can effectively isolate the surface of the battery cell. By adding convex rib features to the edge of the buffer 18, the surface of the battery cell can be effectively isolated, and the blue film on the surface of the battery cell can be protected to prevent damage to the blue film.

[0069] In some embodiments, the first core material layer 13 , the second core material layer 14 and the third core material layer 15 may be sewn together by weaving threads.

[0070] That is to say, the heat insulating core material composed of different core material layers can be knitted in a mesh structure after being combined. The combined heat insulating core material is not easy to break along the joint due to the restraint of the knitted structure, which improves the overall rigidity and strength of the battery core heat insulating pad, ensures the stability of the heat insulating effect of the battery core heat insulating pad, and the woven threads can be sewn to form a mesh knitted structure.

[0071] In some embodiments, the minimum thickness t1 of the first insulation portion 131 is greater than or equal to 1.5 mm and less than or equal to 5 mm, and the maximum thermal conductivity λ1 of the first insulation portion 131 in the thickness direction is greater than or equal to 0.01 W / m·K and less than or equal to 0.08 W / m·K.

[0072] The thickness of the first heat insulating portion 131 affects the heat insulating performance of the middle area of ​​the first core material layer 13. By controlling the thickness of the first heat insulating portion 131, it is possible to avoid the middle area of ​​the first core material layer 13 not being able to provide a high heat insulating effect due to too small a thickness. At the same time, it is also possible to avoid the waste of material due to too large a thickness in the middle area of ​​the first core material layer 13, which is not conducive to giving full play to the heat insulating performance of the material. The minimum thickness t1 of the first heat insulating portion 131 can be controlled within the range of 1.5 mm to 5 mm, for example, 1.5 mm, 2 mm, 2.5 mm, 3 mm, 3.5 mm, 4 mm, 4.5 mm or 5 mm.

[0073] The maximum thermal conductivity λ1 of the first thermal insulation part 131 in the thickness direction also affects the thermal insulation performance of the middle area of ​​the first core material layer 13. By controlling the maximum thermal conductivity λ1 of the first thermal insulation part 131 in the thickness direction, it is possible to avoid increasing the material cost of the middle area of ​​the first core material layer 13 due to too low thermal conductivity. At the same time, it is also possible to avoid the middle area of ​​the first core material layer 13 not being able to provide a good thermal insulation effect due to too high thermal conductivity. The maximum thermal conductivity λ1 of the first thermal insulation part 131 in the thickness direction can be controlled within the range of 0.01W / m·K to 0.08W / m·K, for example 0.01W / m·K, 0.02W / m·K, 0.04W / m·K, 0.06W / m·K or 0.08W / m·K.

[0074] In actual situations, the insulation core material can be aerogel, nano insulation pad, ceramic silicone foam, mica, MPP (Microcellular Polypropylene), silicone and other insulation materials. The hot melt film material can be PET, PC (Polycarbonate) and other film materials. The buffer foam can be silicone, ceramic silicone foam, MPP, rubber and the like. The adhesive layer is generally 3M glue, pressure-sensitive adhesive and other glue. The combination of the materials is by gluing, hot pressing and the like.

[0075] Aerogel insulation core material has a low thermal conductivity and good flame retardant properties, which can effectively block the chain reaction caused by thermal runaway of battery cells. When a battery cell experiences thermal runaway, the temperature on the surface of the battery cell rises, and the insulation core material can delay the transfer of heat to other battery cells, thereby effectively preventing the spread of heat. That is, the battery cell insulation pad can effectively prevent heat from being transferred from the battery cell experiencing thermal runaway to the battery cell that has not experienced thermal runaway. When a battery cell experiencing thermal runaway catches fire, the battery cell insulation pad can also isolate the catching fire from the battery cell that has not experienced thermal runaway, thereby preventing the spread of thermal runaway between stacked battery cells.

[0076] In addition, aerogel has extremely high porosity, specific surface area, excellent chemical stability and flame retardancy, and is lightweight, which can play a good flame retardant role and is conducive to achieving lightweight.

[0077] Different attached film layers can be pre-made into packaging bag structures, which can be loaded with thermal insulation core materials and then hot-pressed and sealed, which can improve the packaging efficiency of the thermal insulation core material and make the battery cell thermal insulation pad more stable, and can meet the customization needs in different situations. Different attached film layers can also be pre-clamped on both sides of the thermal insulation core material, and a recessed accommodating area can be formed on at least one packaging film to locate the position of the thermal insulation core material. The attached film layer is then fixed by hot pressing. Different attached film layers can also be formed by bending the same film layer, folding the same film layer in half to form two oppositely arranged attached film layers, and sandwiching the thermal insulation core material in the middle. The other edges outside the folded edges are then hot-pressed and fixed to complete the fixation of the thermal insulation core material.

[0078] The material of the attached film layer can be a polymer, including but not limited to PET film, PI (Polyimide) film, PVC (Polyvinylchlorid, polyvinyl chloride) film, PP (Polypropylene, polypropylene) film. It has a low thermal conductivity and can improve the thermal insulation effect of the entire battery cell thermal insulation pad. At the same time, the self-adhesiveness of the attached film layer can ensure the coating effect of the thermal insulation core material, so that the structure of the battery cell thermal insulation pad is stable, low cost, and light weight, which is conducive to achieving lightweight battery modules.

[0079] Some embodiments of the present application also provide a battery pack, comprising a box, a battery module and the above-mentioned battery cell thermal insulation pad. The box has a receiving cavity. The battery module is arranged in the receiving cavity, and the battery module includes a plurality of battery cells arranged in the same direction, and two end plates clamping the plurality of battery cells in the middle. The battery cell thermal insulation pad is arranged between two adjacent battery cells or between the battery cell and the end plate.

[0080] When the battery cell thermal insulation pad is set between two adjacent battery cells, it can play a role of thermal insulation between the two adjacent battery cells, and prevent the heat from quickly spreading from the runaway battery cell to other battery cells when a battery cell has thermal runaway, thereby improving the safety of the battery pack. At the same time, it can also prevent electrical contact between two adjacent battery cells and cause short circuits, thereby ensuring the reliability of the battery pack. When the battery cell thermal insulation pad is located between the battery cell at the edge and the end plate, it can play a role of thermal insulation between the battery cell and the inner wall of the box, and prevent the heat generated by the battery cell from being directly transferred to the box, causing the temperature inside the battery pack to rise too quickly. The difference in thermal insulation performance in different areas of the battery cell thermal insulation pad ensures the thermal insulation effect on different areas of the battery cell surface, which is more conducive to improving the safety of the battery pack.

[0081] In addition, the projection of the battery cell insulation pad toward the surface of the battery cell is located within the edge of the battery cell surface, the length of the surface of the battery cell toward the battery cell insulation pad is Lc, the width of the surface of the battery cell toward the battery cell insulation pad is Wc, the length of the first core material layer 13 of the battery cell insulation pad is L1, the width of the first core material layer 13 of the battery cell insulation pad is W1, L1 is greater than or equal to 0.92Lc and less than or equal to 0.95Lc, and W1 is greater than or equal to 0.9Wc and less than or equal to 0.97Wc.

[0082] By making the size of the thermal insulation core material of the battery cell thermal insulation pad close to the size of the battery cell surface, it can be ensured that the battery cell thermal insulation pad can play a good thermal insulation role on the entire battery cell surface. At the same time, the thermal insulation performance of the thermal insulation material can be better utilized to avoid material waste.

[0083] Those skilled in the art will appreciate that the above-mentioned embodiments are specific examples for implementing the present application, and in actual applications, various changes may be made thereto in form and detail without departing from the spirit and scope of the present application.

Claims

1. A battery cell thermal insulation pad, used for attaching to the surface of a battery cell for thermal insulation, characterized in that: The battery core thermal insulation pad comprises: A first attachment film layer includes a first packaging portion and a first peripheral portion surrounding the first packaging portion; A second attachment film layer includes a second packaging portion and a second peripheral portion surrounding the second packaging portion, wherein a containing cavity is formed between the second packaging portion and the first packaging portion, and the second peripheral portion is connected to the first peripheral portion; A first core material layer is arranged in the accommodating cavity, and the first core material layer includes a first thermal insulation part and a second thermal insulation part surrounding the first thermal insulation part, the minimum thickness of the first thermal insulation part is t1, and the maximum thermal conductivity of the first thermal insulation part in the thickness direction is λ1, the thickness of the second thermal insulation part is t2, and the thermal conductivity of the second thermal insulation part in the thickness direction is λ2, and t1 is greater than t2 and / or λ1 is smaller than λ2.

2. The battery core thermal insulation pad according to claim 1, characterized in that: The first thermal insulation part includes a first part and a second part surrounding the first part, the second part is connected to the second thermal insulation part at an edge away from the first part, the thickness of the first part is ta, the thermal conductivity of the first part in the thickness direction is λa, the thickness of the second part is tb, the thermal conductivity of the second part in the thickness direction is λb, the ta is greater than the tb and / or the λa is less than the λb.

3. The battery core thermal insulation pad according to claim 2, characterized in that: The ratio of the ta to the tb is 1.1 to 1.5, and the ratio of the tb to the t2 is 1.3 to 1.

7.

4. The battery core thermal insulation pad according to claim 3, characterized in that: The area of ​​the first part is S1, the area of ​​the second part is S2, the area of ​​the second heat insulation part is S3, the ratio of S1 to S2 is 0.11 to 0.20, and the ratio of S2 to S3 is 1.1 to 2.

0.

5. The battery core thermal insulation pad according to claim 1, characterized in that: It also includes a second core material layer, which is adhered to the side of the first core material layer close to the first attached film layer. The second core material layer includes a third thermal insulation part and a fourth thermal insulation part surrounding the third thermal insulation part. The thickness of the third thermal insulation part is t3, and the thermal conductivity of the third thermal insulation part in the thickness direction is λ3. The thickness of the fourth thermal insulation part is t4, and the thermal conductivity of the fourth thermal insulation part in the thickness direction is λ4. The t3 is greater than the t4 and / or the λ3 is smaller than the λ4.

6. The battery core thermal insulation pad according to claim 5, characterized in that: It also includes a third core material layer, which is adhered to the side of the second core material layer away from the first core material layer. The third core material layer includes a fifth insulation part and a sixth insulation part surrounding the fifth insulation part. The thickness of the fifth insulation part is t5, and the thermal conductivity of the fifth insulation part in the thickness direction is λ5. The thickness of the sixth insulation part is t6, and the thermal conductivity of the sixth insulation part in the thickness direction is λ6. The t5 is greater than the t6 and / or the λ5 is smaller than the λ6.

7. The battery cell thermal insulation pad according to claim 6, characterized in that: The projection of the third thermal insulation part toward the first core material layer is located within the edge of the first thermal insulation part, and the projection of the fifth thermal insulation part toward the second core material layer is located within the edge of the third thermal insulation part.

8. The battery core thermal insulation pad according to any one of claims 1 to 7, characterized in that: It also includes a first adhesive layer and a second adhesive layer, the first adhesive layer is attached to a side of the first attached film layer away from the second attached film layer, the second adhesive layer is attached to a side of the second attached film layer away from the first attached film layer, a first release paper is provided on the side of the first adhesive layer away from the first attached film layer, and a second release paper is provided on the side of the second adhesive layer away from the second attached film layer.

9. The battery core thermal insulation pad according to claim 8, characterized in that: It also includes a buffer component, which is arranged between the first attachment film layer and the first adhesive layer, and the projection of the buffer component on the first attachment film layer is arranged around the first packaging part.

10. The battery core thermal insulation pad according to claim 9, characterized in that: The buffer member is provided with a plurality of through holes, and the plurality of through holes are arranged around the center of the buffer member.

11. The battery core thermal insulation pad according to claim 9, characterized in that: The buffer is provided with ribs, and the ribs are protruded from the edge of the buffer toward a direction away from the center.

12. The battery core thermal insulation pad according to claim 6 or 7, characterized in that: The first core material layer, the second core material layer and the third core material layer are sewn together by weaving thread.

13. The battery core thermal insulation pad according to claim 1, characterized in that: The t1 is greater than or equal to 1.5 mm and less than or equal to 5 mm, and the λ1 is greater than or equal to 0.01 W / m·K and less than or equal to 0.08 W / m·K.

14. A battery pack, characterized in that: include: A box body having a containing cavity; A battery module is arranged in the accommodating cavity, wherein the battery module comprises a plurality of battery cells arranged in the same direction and two end plates sandwiching the plurality of battery cells; The battery cell thermal insulation pad according to any one of claims 1 to 13 is arranged between two adjacent battery cells or between the battery cell and the end plate.

15. The battery pack according to claim 14, characterized in that: include: The projection of the battery cell thermal insulation pad toward the surface of the battery cell is located within the edge of the battery cell surface, the length of the surface of the battery cell facing the battery cell thermal insulation pad is Lc, the width of the surface of the battery cell facing the battery cell thermal insulation pad is Wc, the length of the first core material layer of the battery cell thermal insulation pad is L1, the width of the first core material layer of the battery cell thermal insulation pad is W1, L1 is greater than or equal to 0.92Lc and less than or equal to 0.95Lc, and W1 is greater than or equal to 0.9Wc and less than or equal to 0.97Wc.

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