Battery-protecting flame retardant sheet and battery assembly comprising same

Abstract

According to the present disclosure, provided is a battery-protecting flame retardant sheet disposed inside or outside a battery assembly, the battery-protecting flame retardant sheet comprising: a flame retardant laminate including a plurality of base sheets, which include a flame retardant material and are stacked in a first direction, and adhesive members interposed between the plurality of base sheets; and a heat insulating member which includes a heat insulating material so as to suppress heat transfer, and which is disposed on at least one of two outermost surfaces of the flame retardant laminate in the first direction.

Description

Flame retardant sheet for battery protection and battery assembly including the same

[0001] This application claims the benefit of priority based on Korean Patent Application No. 10-2024-0144071 filed on October 21, 2024, and all contents disclosed in the document of said Korean Patent Application are incorporated herein as part of this specification.

[0002] The present disclosure relates to a flame-retardant sheet for battery protection and a battery assembly including the same.

[0003] Secondary batteries are rechargeable and dischargeable, so they are widely used in mobile devices such as digital cameras, mobile phones, and laptops. In particular, they are recently attracting attention as an energy source for electric vehicles and Energy Storage Systems (ESS).

[0004] As high capacity and high output power are required in electric vehicles and power storage devices, battery assemblies, which are high-capacity battery devices such as battery modules housing multiple secondary batteries (battery cells) inside a housing, battery packs containing multiple battery modules, or CTPs (Cell To Packs) directly housing multiple secondary batteries in a pack, are being widely utilized.

[0005] Meanwhile, in a battery pack where multiple battery modules are densely arranged, if a thermal runaway occurs in any one battery module, there is a risk that the fire will spread to adjacent battery modules and intensify into the entire battery pack; similarly, in a CTP structure, there is a risk that the fire will spread from one battery cell to an adjacent battery cell and intensify into the entire CTP.

[0006] In addition, if the internal pressure of the battery assembly increases above a certain level due to gas generated inside the battery assembly from a fire, there is a risk that the battery assembly may explode.

[0007] To solve these problems, a battery protection means is required that can prevent the spread of flames to adjacent battery assemblies even if a fire occurs inside the battery assembly, while at the same time appropriately controlling the internal pressure of the battery assembly so that it does not increase above a dangerous level.

[0008] The present disclosure is designed to solve at least some of the problems of the prior art described above, and provides a flame-retardant sheet for battery protection that has a thin thickness while possessing a high level of thermal insulation and flame resistance.

[0009] In addition, the present disclosure provides a flame-retardant sheet for battery protection having an appropriate level of burst strength to prevent the explosion of a battery assembly.

[0010] A flame-retardant sheet for battery protection disposed inside or outside a battery assembly according to one embodiment of the present disclosure may include a flame-retardant laminate comprising a plurality of base sheets laminated along a first direction and an adhesive member interposed between the plurality of base sheets, and a thermal insulation member disposed on at least one of the outermost two sides in the first direction of the flame-retardant laminate, which is provided to suppress heat transfer by including a thermal insulation material.

[0011] According to one embodiment, the flame-retardant material of the plurality of base sheets may be formed of synthetic mica.

[0012] According to one embodiment, the total thickness in the first direction including the flame-retardant laminate and the thermal insulation member may be 0.05 mm or more and 0.3 mm or less.

[0013] According to one embodiment, the minimum value of the thickness of the base sheet may be 0.006 mm.

[0014] According to one embodiment, the insulating material of the insulating member may include a ceramic material.

[0015] According to one embodiment, the insulating member may be coated on both sides of the flame-retardant laminate.

[0016] According to one embodiment, the thickness of the insulating member may be 0.02 mm or more and 0.1 mm or less.

[0017] According to one embodiment, the flame-retardant laminate and the thermal insulation member stacked in the first direction may be arranged so that the maximum value of the burst strength against an external force acting in the first direction is 500 kPa.

[0018] According to another embodiment, the adhesive member may be partially interposed with respect to one surface of the base sheet.

[0019] According to another embodiment, the flame-retardant laminate may include an air gap formed between the adhesive members that are partially interposed.

[0020] According to one embodiment, a battery assembly may be provided comprising a flame-retardant sheet for protecting the battery, a plurality of battery cells, and a main frame that accommodates the plurality of battery cells.

[0021] According to one embodiment of the present disclosure, a flame-retardant sheet for battery protection can be provided having a thin thickness while simultaneously possessing thermal insulation, flame resistance, and burst strength within a desired range.

[0022] FIG. 1 is an exploded perspective view illustrating a battery assembly to which a flame-retardant sheet for battery protection according to one embodiment of the present disclosure is applied.

[0023] FIG. 2 is a cross-sectional view showing a cross-section of a battery assembly with a flame-retardant sheet for battery protection according to one embodiment of the present disclosure, cut along line I-I' of FIG. 1.

[0024] Figure 3 is a cross-sectional view illustrating the thermal runaway situation of the battery assembly of Figure 2.

[0025] FIG. 4 is a cross-sectional view showing a cross-section of a flame-retardant sheet for battery protection according to one embodiment of the present disclosure, cut along line I-I' of FIG. 1.

[0026] FIG. 5 is a cross-sectional view showing a cross-section of a flame-retardant sheet for battery protection according to another embodiment of the present disclosure, cut along line I-I' of FIG. 1.

[0027] FIG. 6 is a graph showing the results of a pyro test for a flame-retardant sheet for battery protection according to one embodiment of the present disclosure.

[0028] In describing the embodiments of the present disclosure, the terms used have been selected to be as widely used as possible, taking into account their functions within the present disclosure; however, these terms may vary depending on the intent of those skilled in the art, case law, the emergence of new technologies, etc. Additionally, in specific cases, terms may be selected at the applicant's discretion, and in such cases, their meanings may be described in detail in the relevant explanatory section. Therefore, the terms used in the present disclosure are not merely names, but may be defined based on their meanings and the overall content of the present disclosure.

[0029] The suffix "part" for components used in this specification is assigned or used interchangeably solely for the sake of ease of drafting the specification and may not have a distinct meaning or role in itself. Furthermore, in describing the embodiments included in this disclosure, if it is determined that a detailed description of related prior art could obscure the essence of the embodiments included in this disclosure, such detailed description may be omitted. Additionally, the attached drawings are intended only to facilitate understanding of the embodiments included in this disclosure, and the technical concept of this disclosure is not limited by the attached drawings; it should be understood that the technical concept and scope of this disclosure include all modifications, equivalents, and substitutions.

[0030] Terms including ordinal numbers, such as first, second, etc., may be used to describe various components, but said components are not limited by said terms, and said terms may be used only for the purpose of distinguishing one component from another.

[0031] When it is stated that a component is "connected" or "connected" to another component, it can be understood that it may be directly connected or connected to that other component, or that there may be other components in between. On the other hand, when it is stated that a component is "directly connected" or "directly connected" to another component, it can be understood that there are no other components in between.

[0032] In this specification, singular expressions may include plural expressions unless the context clearly indicates otherwise.

[0033] Terms such as "comprising" or "having" as used in this specification are intended to indicate the existence of the features, numbers, steps, actions, components, parts, or combinations thereof described in the specification, and should not be understood as not precluding the existence or addition of one or more other features, numbers, steps, actions, components, parts, or combinations thereof.

[0034] The expression "at least one of a, b, and c" as described in this specification may include 'a alone', 'b alone', 'c alone', 'a and b', 'a and c', 'b and c', or 'a, b, and c all'.

[0035] Embodiments of the present disclosure are described below with reference to the attached drawings so that those skilled in the art can easily implement them. However, the present disclosure may be embodied in various different forms and is not limited to the embodiments described herein.

[0036] The battery assembly referred to in this specification may mean a high-capacity battery device containing multiple battery cells, such as a battery module, a battery pack, or a CTP (Cell To Pack).

[0037] Embodiments of the present disclosure will be described in detail below with reference to the drawings.

[0038] FIG. 1 is an exploded perspective view showing a battery assembly (10) with a flame-retardant sheet (300) for battery protection applied according to one embodiment of the present disclosure, FIG. 2 is a cross-sectional view showing a cross-section of a battery assembly (10) with a flame-retardant sheet (300) for battery protection applied according to one embodiment of the present disclosure, cut along line I-I' of FIG. 1, and FIG. 3 is a cross-sectional view showing a thermal runaway situation of the battery assembly (10) of FIG. 2.

[0039] Referring to FIGS. 1 to 3, a battery assembly (10) to which a flame-retardant sheet (300) for battery protection according to one embodiment of the present disclosure is applied may include a plurality of battery cells (100).

[0040] A plurality of battery cells (100) according to one embodiment of the present disclosure may be rechargeable secondary batteries. The battery cells (100) may be secondary batteries of various types, such as pouch type, prismatic type, or cylindrical type. However, for convenience, the present specification illustrates a case where a pouch-type battery cell (100) is applied, and does not exclude cases where other types of secondary batteries, such as prismatic and cylindrical types, are applied.

[0041] A battery assembly (10) to which a flame-retardant sheet (300) for battery protection according to one embodiment of the present disclosure is applied may include a main frame (200). The main frame (200) may accommodate a plurality of battery cells (100). For example, referring to FIGS. 2 and 3, the main frame (200) may be composed of a lower frame (210) and a side frame (220). The lower frame (210) may be a plate located at the bottom of the plurality of battery cells (100). The side frame (220) may be a wall formed along the perimeter of the lower frame (210). The main frame (200) forms a predetermined space by the lower frame (210) and the side frame (220), and may accommodate a plurality of battery cells (100) in the space.

[0042] A battery assembly (10) to which a flame-retardant sheet (300) for battery protection according to one embodiment of the present disclosure is applied may include an upper cover (400). The upper cover (400) may be provided to cover the upper part of the main frame (200). At this time, the upper cover (400) may include at least one venting hole (410). The venting hole (410) is formed by penetrating one surface of the upper cover (400) in a vertical direction and may be a hole for discharging high-pressure gas or foreign substances to the outside of the battery assembly (10) in the event that thermal runaway occurs inside the battery assembly (10).

[0043] A flame-retardant sheet (300) for battery protection according to one embodiment of the present disclosure may be placed inside or outside a battery assembly (10). For example, the flame-retardant sheet (300) for battery protection may be placed between an upper cover (400) and a plurality of battery cells (100). If thermal runaway occurs in any one of the plurality of battery cells (100), the flame-retardant sheet located above it can withstand high temperatures and prevent the propagation of flames.

[0044] However, in the event of a thermal runaway of the battery cell (100), if the internal pressure of the battery assembly (10) rises excessively high, the risk of explosion may increase. Therefore, the battery protection flame retardant sheet (300) may be provided to rupture due to the internal pressure of the battery assembly (10) when the internal pressure of the battery assembly (10) reaches a predetermined pressure level. High-pressure gas or foreign substances inside the battery assembly (10) may be discharged through the ruptured gap of the battery protection flame retardant sheet (300), and accordingly, the internal pressure of the battery assembly (10) may not increase beyond a certain level. In the event of a thermal runaway, a part of the battery protection flame retardant sheet (300) corresponding to the location of the venting hole (410) (e.g., 301 in FIGS. 2 and 3) may be deformed outward due to the internal pressure of the battery assembly (10). The battery protection flame retardant sheet (300) is deformed by the internal pressure of the battery assembly (10), i.e., external force, and can be arranged to rupture at a pressure above a certain level.

[0045] A conventional flame retardant sheet may include a notch formed in a portion facing the venting hole of the upper cover. The notch may be a portion of the conventional flame retardant sheet designed to break under pressure exceeding a certain level. The notch may be a portion of the conventional flame retardant sheet made relatively weaker than other parts by forming it thinner or creating a groove. Since an additional process of processing the notch into the flame retardant sheet is required to form such a notch, there is a problem in that the manufacturing process becomes complex.

[0046] Referring to FIGS. 1 to 3, unlike a conventional battery assembly, the flame retardant sheet (300) included in the battery assembly (10) according to one embodiment of the present disclosure may be provided such that no notching is formed in the portion (301) facing the venting hole (410). The flame retardant sheet (300) according to one embodiment of the present disclosure is provided to satisfy the burst strength test described later, so that it may break at a pressure above a certain level even without notching. Therefore, a separate process for processing notching may not be required.

[0047] A flame-retardant sheet (300) for battery protection according to one embodiment of the present disclosure may be provided to pass two tests. The two tests are a pyro test and a burst strength test.

[0048] The pyro test described in the present disclosure can be performed by applying a flame to one side of a flame-retardant sheet (300) for battery protection. For example, the pyro test can be performed as follows. First, the flame-retardant sheet (300) for battery protection to be tested is cut to prepare a rectangular specimen with a width of 100 mm and a height of 100 mm. Then, a flame is applied to the prepared specimen, maintaining a distance of approximately 140 mm between the specimen and the outlet through which the flame is discharged. The temperature of the flame reaching the specimen is set to be between ± 10% of 1100°C. The flame is applied for about 10 minutes, and then the condition of the specimen is checked to determine whether the test is passed.

[0049] The passing criteria for the pyro test described in this disclosure is that when a flame under the conditions described above is applied, the flame must not pass through the back surface of the specimen, and the temperature of the back surface must be 300°C or lower.

[0050] The burst strength test referred to in this disclosure may be a test according to ISO (International Organization for Standardization) 2758:2014. For example, the burst strength test may be a test in which pressure is applied in a direction perpendicular to one surface of a specimen to measure the pressure at which the specimen bursts.

[0051] The passing criterion for the burst strength test referred to in the present disclosure is that the burst strength must be 500 kPa or less.

[0052] The thickness of the battery protection flame retardant sheet (300) applied to the battery assembly (10) may be as thin as possible, taking into account the packaging size and energy density of the battery assembly (10). To this end, the battery protection flame retardant sheet (300) according to the present disclosure may be provided such that the total thickness is 0.3 mm or less. However, in order to prevent or delay the propagation of flame to adjacent battery assemblies (10) in the event of thermal runaway, the battery protection flame retardant sheet (300) needs to have thermal insulation and heat resistance of a certain level or higher, and may need to rupture at a pressure above a certain level to reduce the risk of explosion. The passing criteria for the above-described pyro test and burst strength test are conditions for satisfying the above-described specifications, and the battery protection flame retardant sheet (300) according to one embodiment of the present disclosure may be provided to satisfy the passing criteria for the pyro test and burst strength test.

[0053] FIG. 4 is a cross-sectional view showing a cross-section along line I-I' of FIG. 1 of a flame-retardant sheet (300) for battery protection according to one embodiment of the present disclosure, and FIG. 5 is a cross-sectional view showing a cross-section of a flame-retardant sheet for battery protection according to another embodiment of the present disclosure cut along line I-I' of FIG. 1.

[0054] Referring to FIG. 4, a flame-retardant sheet (300) for battery protection according to one embodiment of the present disclosure may include a base sheet (311).

[0055] A base sheet (311) according to one embodiment of the present disclosure may include a flame-retardant material. For example, the flame-retardant material may include synthetic mica. Synthetic mica may have excellent flame resistance, insulation, and chemical resistance. Synthetic mica can be artificially synthesized through a chemical process and thus may have uniform purity. In contrast, natural mica is processed from natural minerals mined, but it has the disadvantage of being difficult to achieve uniform purity compared to synthetic mica. A base sheet (311) according to one embodiment of the present disclosure is formed from synthetic mica, and thus can have a thinner thickness than when formed from natural mica, while ensuring uniform flame resistance over the entire sheet.

[0056] Referring to FIG. 4, a flame-retardant sheet (300) for battery protection according to one embodiment of the present disclosure may include a plurality of base sheets (311) stacked in a first direction (e.g., a direction parallel to the Z-axis direction). The plurality of base sheets (311) may be composed of thin layers and stacked in layers, and the direction of stacking may be defined as the first direction (Z-axis direction).

[0057] When the flame-retardant layer of the battery protection flame-retardant sheet (300) is composed of a flame-retardant laminate (310) in which a plurality of thin base sheets (311) are laminated, greater flame resistance can be secured compared to composing the flame-retardant layer with a single layer of thick base sheets (311). For example, a plurality of base sheets (311) laminated along a first direction (Z-axis direction) may have the effect of delaying heat transfer due to a predetermined gap formed between them.

[0058] In addition, when the total thickness (d) of the flame retardant sheet is formed equally, compared to when the flame retardant layer is composed of a single layer of base sheet (311), when the flame retardant layer is composed of a flame retardant laminate (310) in which a plurality of thin base sheets (311) are laminated, the burst strength of the flame retardant layer is relatively low, so a burst strength of 500 kPa or less can be easily secured.

[0059] At this time, the minimum thickness of the base sheet (311) according to one embodiment of the present disclosure may be 0.006 mm. If formed to be smaller than 0.006 mm, sufficient rigidity may not be secured, and it may be easily damaged even by a small external force. The maximum thickness of the base sheet (311) may be limited to a range that satisfies the total thickness (d) of the flame-retardant sheet (300) for battery protection according to the present disclosure. For example, if the total thickness (d) is 0.3 mm, and an insulating member of 0.02 mm is placed on each side of the flame-retardant laminate (310), and two base sheets (311) are applied, and the thickness of the adhesive member (312) is ignored, the maximum thickness of each base sheet (311) may be 0.13 mm.

[0060] A flame-retardant sheet (300) for battery protection according to one embodiment of the present disclosure may include an adhesive member (312). The adhesive member (312) may be interposed between a plurality of base sheets (311). The adhesive member (312) may bond and fix adjacent base sheets (311). The type of adhesive member (312) may vary, and the adhesive member (312) may be appropriately selected within a range that is chemically stable, has strong heat resistance, and does not interfere with the purpose of the present disclosure.

[0061] Referring to FIG. 5, an adhesive member (312) according to one embodiment of the present disclosure may be partially interposed with respect to one surface of a base sheet (311). For example, the adhesive member (312) may not be applied or placed entirely on one surface of the base sheet (311), but may be applied or placed partially spaced apart.

[0062] The flame-retardant laminate (310) of the present disclosure may include an air gap (315). The air gap (315) may be formed between partially interposed adhesive members (312). At this time, the adhesive members (312) of the present disclosure may have a predetermined thickness so that adjacent base sheets (311) are sufficiently spaced apart. The air gap (315) may be formed between adjacent base sheets (311) to enhance the thermal insulation effect. That is, heat transferred from any one of the base sheets (311) may pass through the air gap (315), thereby delaying heat transfer.

[0063] A flame-retardant sheet (300) for battery protection according to one embodiment of the present disclosure may include an insulating member (320).

[0064] An insulating member (320) according to one embodiment of the present disclosure may be provided to suppress heat transfer by including an insulating material. For example, the insulating material may include a ceramic material. Specifically, the insulating material may be composed of a ceramic-based coating agent. For example, the ceramic-based coating agent may include one or more of an aluminum oxide (Al2O3) coating, a zirconium oxide (ZrO2) coating, a titania (TiO2) coating, silica-based coatings, and glass ceramic coatings.

[0065] An insulating member (320) according to one embodiment of the present disclosure may be disposed on at least one of the two outermost surfaces in the first direction (Z-axis direction) of the flame-retardant laminate (310). For example, the insulating member (320) may be disposed on both surfaces of the flame-retardant laminate (310). The flame-retardant laminate (310) may include a first surface (313) and a second surface (314). The first surface (313) may be a surface facing the upper cover (400) when applied to the battery assembly (10), and the second surface (314) may be a surface opposite to the first surface (313) and facing the plurality of battery cells (100). The insulating member (320) may be disposed laminated on the first surface (313) and the second surface (314). In other words, the insulating member (320) can be coated on the first surface (313) and the second surface (314), respectively.

[0066] According to one embodiment of the present disclosure, the thickness of the insulating member (320) may be 0.02 mm or more and 0.1 mm or less. The insulating member (320) is coated on at least one surface of the flame-retardant laminate (310) so that an excellent insulating effect can be secured with only a thin thickness. The insulating member (320) may be a ceramic-based coating layer. To ensure sufficient insulating properties, the insulating member (320) may be coated with a thickness of 0.02 mm or more. However, considering that the total thickness (d) of the flame-retardant sheet (300) for battery protection increases, the insulating member (320) may be formed with a thickness of 0.1 mm or less.

[0067] The total thickness (d) of the flame-retardant sheet (300) for battery protection according to one embodiment of the present disclosure may be 0.05 mm or more and 0.3 mm or less. The total thickness (d) may refer to the thickness in the first direction (Z-axis direction) including the flame-retardant laminate (310) and the insulating member (320). When considering the packaging size of the battery assembly (10), the maximum value of the total thickness (d) may be 0.3 mm, and the minimum value of the total thickness (d) may be 0.05 mm to satisfy the passing criteria for the Pyro test and the burst strength test. If the total thickness (d) of the flame-retardant sheet (300) for battery protection exceeds 0.3 mm, it may cause a change in the packaging size of the battery assembly (10), making it difficult to apply to the battery assembly (10). In addition, if the total thickness (d) of the battery protection flame retardant sheet (300) exceeds 0.3 mm, it may be difficult to pass the burst strength test. Furthermore, if the total thickness (d) of the battery protection flame retardant sheet (300) is 0.005 mm or less, it may not pass the pyro test because sufficient flame resistance is not secured.

[0068] FIG. 6 is a graph showing the temperature (T1) on the front side and the temperature (T2) on the back side of the flame retardant sheet over time, with the total thickness (d) of the flame retardant sheet (300) for battery protection formed to 0.12 mm according to one embodiment of the present disclosure and a pyro test being performed.

[0069] The time at which the flame was applied was set to 0.0 (sec), and the temperature of the front side (T1) and the back side (T2) of the flame retardant sheet were measured over time. Additionally, the point in time 300 (sec) after the start of the test was set to A, and the point in time 900 (sec) after the start of the test was set to B. The result of calculating the temperature of the back side (T2) in the interval between A and B is as shown in [Table 1] below.

[0070] Temperature of A Temperature of B Minimum temperature within AB section Maximum temperature within AB section Average temperature within AB section Front +979.7 ℃ +975.2 ℃ +972.1 ℃ +999.9 ℃ +984.9 ℃ Back +263.2 ℃ +274.2 ℃ +256.9 ℃ +282.3 ℃ +271.7 ℃

[0071] As shown in Table 1, it can be confirmed that the temperature of the back surface (T2) is less than 300°C at the point where 600 seconds (sec), which is 10 minutes after the start of the Pyro test, has elapsed. Even when checking the average and maximum values ​​of the temperature of the back surface (T2) in the AB section before and after the 600-second (sec) point, it can be confirmed that the temperature of the back surface (T2) does not exceed 300°C.

[0072] In addition, the total thickness (d) of the flame-retardant sheet (300) for battery protection according to one embodiment of the present disclosure was formed to be 0.12 mm, and a burst strength test was conducted twice. As a result, the burst strength was measured to be 324.64 kPa and 328.02 kPa, respectively, and it was confirmed that it was 500 kPa or less.

[0073] Although the present disclosure has been illustrated and described in connection with preferred embodiments to illustrate the principles of the present disclosure, the present disclosure is not limited to the configuration and operation as illustrated and described. Rather, those skilled in the art will understand that numerous changes and modifications to the present disclosure are possible without departing from the spirit and scope of the appended claims.

Claims

1. A flame-retardant sheet for battery protection disposed inside or outside a battery assembly, A flame-retardant laminate comprising a plurality of base sheets laminated along a first direction and an adhesive member interposed between the plurality of base sheets, the base sheets comprising a flame-retardant material; and A flame-retardant sheet for battery protection comprising: a thermal insulation member arranged to suppress heat transfer by including a thermal insulation material and disposed on at least one of the outermost two sides in the first direction of the flame-retardant laminate.

2. In Paragraph 1, The flame-retardant material of the plurality of base sheets above is a flame-retardant sheet for battery protection comprising synthetic mica.

3. In Paragraph 2, A flame-retardant sheet for battery protection, comprising the flame-retardant laminate and the thermal insulation member, wherein the total thickness in the first direction is 0.05 mm or more and 0.3 mm or less.

4. In Paragraph 3, A flame-retardant sheet for battery protection having a minimum thickness of 0.006 mm of the base sheet.

5. In Paragraph 4, The insulating material of the above-mentioned insulating member is a flame-retardant sheet for battery protection comprising a ceramic material.

6. In Paragraph 5, The above-mentioned insulating member is a flame-retardant sheet for battery protection coated on both sides of the above-mentioned flame-retardant laminate.

7. In Paragraph 6, A flame-retardant sheet for battery protection having a thickness of 0.02 mm or more and 0.1 mm or less of the above-mentioned insulating member.

8. In Paragraph 7, A flame-retardant sheet for battery protection, wherein the flame-retardant laminate and the insulating member laminated in the first direction are arranged such that the maximum value of the burst strength against an external force acting in the first direction is 500 kPa.

9. In Paragraph 1, The adhesive member is a flame-retardant sheet for battery protection partially interposed on one side of the base sheet.

10. In Paragraph 9, The above flame-retardant laminate is a flame-retardant sheet for battery protection comprising an air gap formed between the adhesive members partially interposed therein.

11. Flame retardant sheet for battery protection according to claim 1; Multiple battery cells; and A battery assembly comprising a main frame that accommodates the plurality of battery cells.

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