Battery pack composite aerogel structure and battery pack

Abstract

The utility model relates to battery technical field discloses battery pack composite aerogel structure and battery pack, wherein the battery pack composite aerogel structure includes: aerogel layer and a pair of reinforcing layer, aerogel layer has the first big face and the second big face of opposite setting along the thickness direction, and the thickness of aerogel layer decreases from center to both ends, a pair of reinforcing layer has a pair of opposite setting vertical surface and a pair of opposite setting cladding, and a pair of cladding are connected with the first big face and the second big face of aerogel layer respectively, and the thickness of reinforcing layer increases from center to both ends, the battery pack composite aerogel structure of the utility model, and the thicker aerogel layer is set in the center, can promote the heat insulation effect, reduce the thermal expansion degree of electric core, and the thicker reinforcing layer is set in both ends, can promote the tear resistance of both ends, effectively reduce the tear risk of electric core shell, and still can reduce the dosage of aerogel layer, and give consideration to light weight and low cost demand.

Description

Technical Field

[0001] This utility model relates to the field of battery technology, specifically to a composite aerogel structure for a battery pack and a battery pack. Background Technology

[0002] With the continuous development and advancement of electric vehicle and new energy battery technologies, the safety of battery cells has attracted increasing attention. During thermal runaway, new energy battery cells experience extremely rapid expansion and generate a large amount of heat, which can even lead to casing tearing, heat propagation, or even fire and explosion. Therefore, suppressing the intensity of thermal runaway and addressing the issue of thermal propagation are paramount to ensuring battery cell safety.

[0003] Currently, the industry commonly uses aerogel filling between battery cells to suppress heat spread. However, directly filling the cells with traditional aerogel has drawbacks such as poor thermal insulation and easy tearing of the casing. In addition, simply thickening the aerogel layer is insufficient to meet the increasingly high energy density requirements of current products. Utility Model Content

[0004] In view of this, the present invention provides a composite aerogel structure for a battery pack and a battery pack, to solve the problems of poor heat insulation and easy tearing of the casing in existing battery packs that fill the cells with aerogel to suppress heat spread.

[0005] In a first aspect, this utility model provides a battery pack composite aerogel structure, comprising:

[0006] The aerogel layer has a first large surface and a second large surface arranged opposite each other along the thickness direction, and the thickness of the aerogel layer decreases from the center to both ends in the W direction of the thickness section.

[0007] A pair of reinforcing layers have a pair of oppositely arranged vertical surfaces and a pair of oppositely arranged covering surfaces. The pair of covering surfaces are respectively connected to the first large surface and the second large surface of the aerogel layer. In the W direction of the thickness section, the thickness of the reinforcing layer increases from the center to both ends.

[0008] Beneficial Effects: The composite aerogel structure of this battery pack incorporates reinforcing layers connected to the first and second large surfaces of the aerogel layer. The aerogel layer provides thermal insulation between the battery cells, while the reinforcing layers suppress the expansion force of the cells, preventing excessive expansion and tearing of the cell casing. The aerogel layer is relatively thicker at the center and thinner at both ends, adapting to the thermal expansion of the cells and improving thermal insulation, reducing the degree of thermal expansion, and suppressing heat spread. Furthermore, the thicker reinforcing layers at both ends and thinner at the center enhance the tear resistance at the ends of the cells, effectively reducing the risk of tearing of the cell casing and improving the safety performance of the cells. Moreover, it reduces the amount of aerogel layer used, thereby lowering operating costs and achieving lightweight design.

[0009] In one alternative embodiment, both the first large surface and the second large surface are arc-shaped surfaces that convex outward toward the reinforcing layer on their respective sides.

[0010] Beneficial effects: Setting the first and second large surfaces of the aerogel layer as convex arc surfaces facilitates uniform force distribution. When the battery cell expands and squeezes the aerogel layer, it can provide a buffering effect and avoid stress concentration at both ends of the battery cell, which could cause the battery cell casing to tear.

[0011] In one alternative embodiment, the first large surface and the second large surface are symmetrically arranged with respect to the center line of the vertical direction of the aerogel layer.

[0012] Beneficial effects: By symmetrically setting the first and second large surfaces relative to the vertical centerline of the aerogel layer, it is possible to further ensure that the aerogel layer is evenly stressed on both sides, thereby improving the overall stability.

[0013] In one optional embodiment, the thickness of the aerogel layer is Y, the thickness of the aerogel layer at its center in the W direction of the thickness section is Y0, and the distance from the center to both ends of the aerogel layer in the W direction of the thickness section is X, satisfying Y = Y0 - 0.0004 × X. 2 .

[0014] Beneficial effects: By controlling the thickness of the aerogel layer and the distance from the center to both ends of the aerogel layer in the W direction of the thickness section to satisfy the above relationship, it is possible to form an aerogel layer and a reinforcing layer with a gradient of thickness, which significantly improves the thermal insulation effect of the aerogel layer and enhances the tear resistance at both ends of the battery cell.

[0015] In one optional embodiment, the aerogel layer includes an aerogel substrate and a flame retardant mixed in the aerogel substrate. The aerogel substrate includes silica aerogel or ceramic aerogel, and the flame retardant includes magnesium hydroxide composite flame retardant or aluminum hydroxide composite flame retardant.

[0016] Beneficial effects: Aerogel substrate has high heat resistance and can withstand the high temperature state under thermal runaway of battery cell for a long time. In addition, silica aerogel or ceramic aerogel has a porous structure and can be doped with flame retardants. The decomposition of flame retardants absorbs heat, reduces the expansion rate of battery cell, slows down heat transfer, and thus inhibits the thermal spread of battery cell to a certain extent.

[0017] In one optional embodiment, the reinforcing layer includes a polymer matrix, the outer surface of which is provided with a high-temperature resistant coating, the polymer matrix including carbon fiber or ceramic fiber, and the high-temperature resistant coating including a silicone rubber coating.

[0018] Beneficial effects: The polymer matrix, made of carbon fiber or ceramic fiber, has high tensile strength, effectively suppressing cell expansion force and preventing excessive expansion and tearing of the cell casing edges. It also exhibits strong corrosion resistance, electrolyte resistance, and a long service life. A high-temperature resistant coating is applied to the outer surface of the polymer matrix to ensure a certain degree of heat stability.

[0019] In one alternative embodiment, in the W direction of the thickness section of the battery pack composite aerogel structure, the mass percentage of the aerogel substrate decreases from the center to both ends, while the mass percentage of the polymer matrix increases from the center to both ends.

[0020] Beneficial effects: By controlling the mass ratio of the aerogel substrate to decrease from the center to both ends, and the mass ratio of the polymer matrix to increase from the center to both ends, a dynamic match between the heat resistance requirements and expansion resistance of the cells can be formed, which can suppress the heat spread of the cells to the greatest extent and reduce the probability of tearing of the cell casing.

[0021] In one optional embodiment, the decomposition temperature of the aerogel layer is T1, which satisfies 400℃≤T1≤1000℃;

[0022] And / or, the tensile strength of the reinforcing layer is σ, which satisfies σ≥50MPa.

[0023] Beneficial effects: By selecting the material of the aerogel layer, the decomposition temperature of the aerogel layer can be adjusted. Controlling the decomposition temperature within a suitable range ensures the high heat resistance of the aerogel layer, thereby inhibiting heat spread. By selecting the material of the reinforcing layer, the tensile strength of the reinforcing layer can be adjusted. Controlling the tensile strength within a suitable range ensures that the reinforcing layer has sufficient resistance to expansion, reducing the probability of tearing of the battery cell casing.

[0024] Secondly, this utility model also provides a battery pack, comprising:

[0025] Box;

[0026] Multiple battery cells are arranged side by side inside the housing;

[0027] At least one of the above-mentioned battery pack composite aerogel structures is disposed between adjacent battery cells. The vertical surfaces of a pair of reinforcing layers of the battery pack composite aerogel structure are respectively covered with fixing adhesive, and are bonded to the large surfaces of adjacent battery cells through the fixing adhesive.

[0028] Beneficial effects: Since the battery pack includes a battery pack composite aerogel structure, it has the same effects as the battery pack composite aerogel structure, which will not be repeated here.

[0029] In one optional embodiment, the battery pack composite aerogel structure is further disposed between the inner wall of the housing and the large surface of the battery cell.

[0030] Beneficial effects: Placing the composite aerogel structure of the battery pack between the inner wall of the casing and the large surface of the battery cell can further suppress the heat spread of the battery cell near the casing and reduce the probability of its casing tearing. Attached Figure Description

[0031] To more clearly illustrate the specific embodiments of this utility model or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0032] Figure 1 This is a schematic diagram of a composite aerogel structure for a battery pack according to an embodiment of the present invention;

[0033] Figure 2 The thermal runaway temperature comparison curves of Comparative Example 1 and Example 1 are for a battery pack composite aerogel structure according to an embodiment of this utility model.

[0034] Explanation of reference numerals in the attached figures:

[0035] 1. Aerogel layer; 101. First large surface; 102. Second large surface; 2. Reinforcing layer; 201. Vertical surface; 202. Covering surface. Detailed Implementation

[0036] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0037] In embodiments of this utility model, a "battery pack" is formed by electrically connecting a certain number of battery cells together and placing them in a housing to protect the battery cells from external impacts, heat, vibration, etc. The battery pack contains two or more battery cells, the specific number depending on the application of the battery pack and the parameters of individual battery groups.

[0038] In the embodiments of this utility model, a "cell" refers to a single battery cell capable of independent charging and discharging. The components of a cell may include a positive electrode, a negative electrode, a separator, an electrolyte, and a casing for encapsulating the positive electrode, negative electrode, separator, and electrolyte. This utility model does not impose any particular limitations on the type or shape of the cell; it can be a blade cell, a square cell, or any other type of cell. The cell in this utility model can be a lithium-ion cell, a potassium-ion cell, a sodium-ion cell, a lithium-sulfur cell, etc., with lithium-ion cells being particularly preferred. During the charging and discharging process, active ions repeatedly insert and extract between the positive and negative electrode plates. The electrolyte acts as a conductor of ions between the positive and negative electrode plates.

[0039] The following is combined Figures 1 to 2 The following describes embodiments of the present invention.

[0040] According to embodiments of the present invention, on the one hand, such as Figure 1 As shown, a battery pack composite aerogel structure is provided, mainly comprising: an aerogel layer 1 and a pair of reinforcing layers 2. The aerogel layer 1 has a first large surface 101 and a second large surface 102 arranged opposite each other along the thickness direction. In the W direction of the thickness section, the thickness of the aerogel layer 1 decreases from the center to both ends. The pair of reinforcing layers 2 have a pair of oppositely arranged vertical surfaces 201 and a pair of oppositely arranged covering surfaces 202. The pair of covering surfaces 202 are respectively connected to the first large surface 101 and the second large surface 102 of the aerogel layer 1. In the W direction of the thickness section, the thickness of the reinforcing layers 2 increases from the center to both ends.

[0041] Therefore, the battery pack composite aerogel structure provided in this embodiment of the present invention has reinforcing layers 2 connected to the first large surface 101 and the second large surface 102 of the aerogel layer 1, respectively. The aerogel layer 1 is used to provide thermal insulation between the battery cells, and the reinforcing layer 2 is used to suppress the expansion force of the battery cells and prevent the battery cell shell from tearing due to excessive expansion. The aerogel layer 1 is relatively thick at the center and relatively thin at both ends, which is adapted to the thermal expansion of the battery cells, thereby improving the thermal insulation effect, reducing the degree of thermal expansion of the battery cells, and suppressing heat spread. In addition, the reinforcing layer 2 is relatively thick at both ends and relatively thin at the center, which can improve the tear resistance at both ends of the battery cells, effectively reduce the risk of tearing of the battery cell shell, and improve the safety performance of the battery cells.

[0042] Specifically, the thickness direction of aerogel layer 1, that is, the thickness direction of reinforcing layer 2, is as follows: Figure 1 As indicated by arrow T in the diagram. The W direction, which is the vertical direction of aerogel layer 1, is as follows. Figure 1 As indicated by the arrow W in the diagram.

[0043] It should be noted that the composite aerogel structure of the battery pack in this embodiment is mainly installed between the large surfaces of adjacent battery cells. The composite aerogel structure of the battery pack is sheet-like and corresponds to the battery cells. The vertical surface 201 of the reinforcing layer 2 is adhered with adhesive and is fixed to the large surface of the battery cell through the adhesive. During thermal runaway of the battery cell, the heat generation at the center of its large surface is greater, and the expansion force is mainly concentrated at both ends of the battery cell. In this embodiment, a thicker aerogel layer 1 is provided at the center, with the thickness of the aerogel layer 1 decreasing from the center to both ends. A thicker reinforcing layer 2 is provided at both ends, with the thickness of the reinforcing layer 2 increasing from the center to both ends. Throughout the entire process of thermal runaway of the battery cell, this significantly improves the heat insulation effect, effectively suppresses heat spread, reduces the expansion degree of the battery cell casing, and effectively reduces the risk of tearing of the battery cell casing.

[0044] Compared to traditional solutions that use a thicker aerogel layer to improve thermal insulation, this embodiment of the invention occupies less space in the battery pack, which helps to increase the energy density of the battery pack. At the same time, it can also save the amount of aerogel layer 1 (saving about 20% to 30%), thereby reducing the cost of use and achieving the requirement of lightweight design.

[0045] In one embodiment, such as Figure 1 As shown, both the first large surface 101 and the second large surface 102 are convex arc surfaces facing the reinforcing layer 2 on their respective sides. Setting the first large surface 101 and the second large surface 102 of the aerogel layer 1 as convex arc surfaces facilitates uniform stress distribution, that is, uniformly dispersing thermal expansion force. When the battery cell expands and squeezes the aerogel layer 1, it can provide a gentler buffering effect and avoid stress concentration at both ends of the battery cell, which could cause the battery cell casing to tear.

[0046] Furthermore, such as Figure 1 As shown, in one embodiment, the first large surface 101 and the second large surface 102 are symmetrically arranged with respect to the vertical centerline of the aerogel layer 1. This symmetrical arrangement of the first large surface 101 and the second large surface 102 with respect to the vertical centerline of the aerogel layer 1 further ensures uniform stress distribution on both sides of the aerogel layer 1, improving overall stability.

[0047] Specifically, the vertical centerline of aerogel layer 1 is as follows: Figure 1 The line OO in the diagram is shown.

[0048] Furthermore, in one embodiment, such as Figure 1As shown, the thickness of aerogel layer 1 is Y, in mm; the thickness of aerogel layer 1 at its center along the W direction of the thickness section is Y0, in mm; the distance from the center to both ends of aerogel layer 1 along the W direction of the thickness section is X, in mm; satisfying Y = Y0 - 0.0004 × X 2 By controlling the thickness of aerogel layer 1 and the distance from the center to both ends of aerogel layer 1 in the W direction of the thickness section to satisfy the above relationship, it is possible to form aerogel layer 1 and reinforcing layer 2 with gradient thickness, which significantly improves the heat insulation effect of aerogel layer 1 and enhances the tear resistance at both ends of the battery cell.

[0049] It should be noted that, in the W direction of the thickness cross-section, the thickness at the center and both ends of aerogel layer 1 can be selected and set as needed. For example, the thickness Y0 of aerogel layer 1 at the center is 14 mm. The distance X from the center to both ends of aerogel layer 1 ranges from 0 mm to 100 mm.

[0050] In other embodiments, the first large surface 101 and the second large surface 102 may also be selected as inclined surfaces as needed.

[0051] It should be noted that the embodiments of this utility model do not limit the materials and structures of the aerogel layer 1 and the reinforcing layer 2, and any existing materials and structures can be selected as needed.

[0052] In one embodiment, the aerogel layer 1 includes an aerogel substrate and a flame retardant mixed within the aerogel substrate. The aerogel substrate includes silica aerogel or ceramic aerogel, and the flame retardant includes a magnesium hydroxide composite flame retardant or an aluminum hydroxide composite flame retardant. The aerogel substrate has high heat resistance and can withstand high temperatures under thermal runaway conditions of the battery cell for extended periods, for example, it can withstand temperatures exceeding 300°C for more than 30 minutes. Silica aerogel or ceramic aerogel has a porous structure and can be doped with flame retardants. The decomposition of the flame retardant absorbs heat, reducing the battery cell expansion rate and delaying heat transfer, thereby inhibiting the thermal propagation of the battery cell to a certain extent.

[0053] In one embodiment, the reinforcing layer 2 includes a polymer matrix with a high-temperature resistant coating on its outer surface. The polymer matrix includes carbon fiber or ceramic fiber, and the high-temperature resistant coating includes a silicone rubber coating. The polymer matrix, made of carbon fiber or ceramic fiber, has high tensile strength, effectively suppressing cell expansion forces and preventing excessive expansion and tearing of the cell casing edges. It also exhibits strong corrosion resistance, electrolyte resistance, and a long service life. The high-temperature resistant coating on the outer surface of the polymer matrix ensures a certain degree of thermal stability.

[0054] In one embodiment, in the W direction of the thickness section of the battery pack composite aerogel structure, the mass percentage of the aerogel substrate decreases from the center to both ends, while the mass percentage of the polymer matrix increases from the center to both ends.

[0055] For example, in the W direction of the thickness section of the battery pack composite aerogel structure, the mass percentage of the aerogel substrate decreases from 70% at the center to 30% at both ends, while the mass percentage of the polymer matrix increases from 20% at the center to 50% at both ends.

[0056] By controlling the mass percentage of the aerogel substrate to decrease from 70% at the center to 30% at both ends, and the mass percentage of the polymer matrix to increase from 20% at the center to 50% at both ends, a dynamic match between the heat resistance requirements and expansion resistance of the cells can be achieved, which can suppress the heat spread of the cells to the greatest extent and reduce the probability of tearing of the cell casing.

[0057] It should be noted that the mass percentage of the aerogel substrate is the ratio of the mass of the aerogel substrate to the total mass of the battery pack composite aerogel structure. Similarly, the mass percentage of the polymer matrix is ​​the ratio of the mass of the polymer matrix to the total mass of the battery pack composite aerogel structure.

[0058] In one embodiment, the decomposition temperature of aerogel layer 1 is T1, satisfying 400℃≤T1≤1000℃. By selecting the material of aerogel layer 1, the decomposition temperature of aerogel layer 1 can be adjusted. Controlling the decomposition temperature of aerogel layer 1 within a suitable range can ensure the high heat resistance of aerogel layer 1, thereby inhibiting heat spread.

[0059] In one embodiment, the tensile strength of the reinforcing layer 2 is σ, which satisfies σ≥50MPa. By selecting the material of the reinforcing layer 2, the tensile strength of the reinforcing layer 2 can be adjusted. Controlling the tensile strength of the reinforcing layer 2 within a suitable range ensures that the reinforcing layer 2 has sufficient resistance to expansion and reduces the probability of tearing of the cell casing.

[0060] The process parameters of the battery pack composite aerogel structure of this utility model are described in further detail below with reference to specific embodiments. This example should not be construed as limiting the scope of protection claimed by this utility model.

[0061] Example 1:

[0062] Aerogel layer 1 comprises silica aerogel (80% by mass) doped with magnesium hydroxide composite flame retardant (20% by mass). The polymer matrix is ​​a carbon fiber and polyimide resin composite material (carbon fiber 50% by mass). The battery pack composite aerogel structure has a width of 200 mm and a thickness of 20 mm. The thickness Y0 of aerogel layer 1 at its center in the W direction of the thickness section is 14 mm, therefore Y = 14 mm - 0.0004 × X2 The maximum distance from the center to both ends of the aerogel layer 1 in the W direction of the thickness section is 100 mm, at which point Y is 10 mm.

[0063] Example 2:

[0064] Aerogel layer 1 comprises silica aerogel (80% by mass) doped with magnesium hydroxide composite flame retardant (20% by mass). The polymer matrix is ​​a carbon fiber and polyimide resin composite material (carbon fiber 50% by mass). The battery pack composite aerogel structure has a width of 300 mm and a thickness of 18 mm. The thickness Y0 of aerogel layer 1 at the center position in the W direction of the thickness section is 14 mm, therefore Y = 14 mm - 0.0004 × X 2 The maximum distance from the center to both ends of the aerogel layer 1 in the W direction of the thickness section is 150 mm, at which point Y is 5 mm.

[0065] Comparative Example 1:

[0066] It adopts a traditional monoaerogel structure with a width of 200 mm and a thickness of 20 mm, and the thickness is uniformly distributed.

[0067] Comparative Example 2:

[0068] It adopts a traditional monoaerogel structure with a width of 300 mm and a thickness of 18 mm, and the thickness is uniformly distributed.

[0069] Triggered single-cell thermal runaway tests were performed on Examples 1, 2, Comparative Example 1, and Comparative Example 2, respectively. The thermal runaway test method involved overcharging a single cell within the battery pack using a constant current method. Overcharging was stopped when the cell voltage dropped by 25% and the temperature rise at the judgment point reached 3°C / s for 3 consecutive seconds. The cell's runaway state was then observed. Test results and characteristic parameters are shown in Table 1 and [Table data missing]. Figure 2 .

[0070] Table 1: Test Results and Feature Parameters

[0071]

[0072] From Table 1 and Figure 2 It can be seen that in the thermal runaway test, the battery pack with the composite aerogel structure of this utility model significantly reduces the intensity of cell thermal runaway compared to the battery pack with the traditional single aerogel structure.

[0073] In Example 1, compared to Comparative Example 1, the expansion rate of the cell casing decreased from 22% to 11%. After thermal runaway, the highest temperature of the large surface area of ​​the cell decreased from about 661°C to about 537°C, and the phenomenon after thermal runaway deteriorated from cell casing tearing and fire to only valve opening and smoke.

[0074] In Example 2, compared to Comparative Example 2, the expansion rate of the cell casing decreased from 16% to 5%. After thermal runaway, the highest temperature of the large surface area of ​​the cell decreased from approximately 499°C to approximately 418°C, and the phenomenon after thermal runaway deteriorated from cell casing tearing and fire to only valve opening and smoke.

[0075] Therefore, the composite aerogel structure of the battery pack provided in this embodiment of the present invention can significantly improve the thermal insulation effect between battery cells, suppress the spread of thermal runaway, and effectively reduce the risk of tearing of the battery cell casing when the battery cells are thermally runaway.

[0076] According to an embodiment of this utility model, another aspect provides a battery pack, mainly comprising: a housing, multiple battery cells, and at least one battery pack composite aerogel structure. Multiple battery cells are arranged side-by-side within the housing. The battery pack composite aerogel structure is disposed between adjacent battery cells, and a pair of reinforcing layers 2 of the battery pack composite aerogel structure have adhesive applied to their vertical surfaces 201, which are then bonded to the large surfaces of adjacent battery cells via the adhesive.

[0077] Since the battery pack includes a battery pack composite aerogel structure, which has the same effect as the battery pack composite aerogel structure, it will not be elaborated again here.

[0078] The battery pack of this utility model embodiment can be applied to applications that require high temperature resistance and expansion resistance, such as electric vehicle battery modules and energy storage system cell modules.

[0079] In one embodiment, the battery pack composite aerogel structure is further disposed between the inner wall of the casing and the large surface of the battery cell. Disposing of the battery pack composite aerogel structure between the inner wall of the casing and the large surface of the battery cell can further suppress heat propagation from the battery cell near the casing and reduce the probability of its casing tearing.

[0080] According to an embodiment of the present invention, in another aspect, a method for preparing a battery pack composite aerogel structure is also provided, comprising:

[0081] S100, mixed silica sol and magnesium hydroxide nanoparticles are dried to form an aerogel layer 1 of a porous aerogel matrix. In the W direction of the thickness section, the thickness of the aerogel layer 1 decreases from the center to both ends.

[0082] S200. Carbon fiber is pre-impregnated in polyimide resin and molded to form a polymer matrix. A silicone rubber coating is sprayed onto the outer surface of the polymer matrix to form a reinforcing layer 2. In the W direction of the thickness section, the thickness of the reinforcing layer 2 increases from the center to both ends.

[0083] S300. Using a layer-by-layer deposition method or hot pressing sintering, the first large surface 101 and the second large surface 102 in the thickness direction of the aerogel layer 1 are seamlessly connected to the covering surface 202 of the reinforcing layer 2 to obtain the battery pack composite aerogel structure.

[0084] The method for preparing the composite aerogel structure of the battery pack provided in this embodiment of the invention involves connecting reinforcing layers 2 to the first large surface 101 and the second large surface 102 of the aerogel layer 1, respectively. The aerogel layer 1 provides thermal insulation between the battery cells, while the reinforcing layers 2 suppress the expansion force of the battery cells, preventing excessive expansion and tearing of the battery cell casing. The aerogel layer 1 is relatively thicker at the center and relatively thinner at both ends, which is adapted to the thermal expansion of the battery cells, thereby improving the thermal insulation effect, reducing the degree of thermal expansion of the battery cells, and suppressing heat spread. In addition, the relatively thicker reinforcing layers 2 at both ends and relatively thinner at the center can improve the tear resistance at both ends of the battery cells, effectively reducing the risk of tearing of the battery cell casing and improving the safety performance of the battery cells. Moreover, it can also reduce the amount of aerogel layer 1 used, thereby reducing the cost of use and achieving the requirement of lightweight design.

[0085] Although embodiments of the present invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the present invention, and such modifications and variations all fall within the scope defined by the appended claims.

Claims

1. A composite aerogel structure for a battery pack, characterized in that, include: The aerogel layer has a first large surface and a second large surface arranged opposite each other along the thickness direction, and the thickness of the aerogel layer decreases from the center to both ends in the W direction of the thickness section. A pair of reinforcing layers have a pair of oppositely arranged vertical surfaces and a pair of oppositely arranged covering surfaces. The pair of covering surfaces are respectively connected to the first large surface and the second large surface of the aerogel layer. In the W direction of the thickness section, the thickness of the reinforcing layer increases from the center to both ends.

2. The battery pack composite aerogel structure according to claim 1, characterized in that, Both the first large surface and the second large surface are arc surfaces that convex outwards toward the reinforcing layer on their respective sides.

3. The battery pack composite aerogel structure according to claim 2, characterized in that, The first large surface and the second large surface are symmetrically arranged with respect to the center line of the vertical direction of the aerogel layer.

4. The battery pack composite aerogel structure according to claim 3, characterized in that, The thickness of the aerogel layer is Y, the thickness of the aerogel layer at the center position in the W direction of the thickness section is Y0, and the distance from the center to both ends of the aerogel layer in the W direction of the thickness section is X, satisfying Y = Y0 - 0.0004 × X 2 .

5. The battery pack composite aerogel structure according to any one of claims 1 to 4, characterized in that, The aerogel layer includes an aerogel substrate and a flame retardant mixed in the aerogel substrate. The aerogel substrate includes silica aerogel or ceramic aerogel, and the flame retardant includes magnesium hydroxide composite flame retardant or aluminum hydroxide composite flame retardant.

6. The battery pack composite aerogel structure according to claim 5, characterized in that, The reinforcing layer includes a polymer matrix, and the outer surface of the polymer matrix is ​​provided with a high-temperature resistant coating. The polymer matrix includes carbon fiber or ceramic fiber, and the high-temperature resistant coating includes a silicone rubber coating.

7. The battery pack composite aerogel structure according to claim 6, characterized in that, In the W direction of the thickness section of the battery pack composite aerogel structure, the mass percentage of the aerogel substrate decreases from the center to both ends, while the mass percentage of the polymer matrix increases from the center to both ends.

8. The battery pack composite aerogel structure according to claim 7, characterized in that, The decomposition temperature of the aerogel layer is T1, which satisfies 400℃≤T1≤1000℃; And / or, the tensile strength of the reinforcing layer is σ, which satisfies σ≥50MPa.

9. A battery pack, characterized in that, include: Box; Multiple battery cells are arranged side by side inside the housing; At least one battery pack composite aerogel structure according to any one of claims 1 to 8, wherein the battery pack composite aerogel structure is disposed between adjacent battery cells, and a pair of reinforcing layers of the battery pack composite aerogel structure are respectively provided with fixing adhesive on their vertical surfaces, and are bonded to the large surfaces of adjacent battery cells through the fixing adhesive.

10. The battery pack according to claim 9, characterized in that, The composite aerogel structure of the battery pack is also disposed between the inner wall of the box and the large surface of the battery cell.

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