Pad for delaying thermal runaway of battery and preventing flames, and battery pack having same

Abstract

Provided is a pad for delaying thermal runaway of a battery and preventing flames. The pad for delaying thermal runaway of a battery and preventing flames, according to an embodiment of the present invention, is implemented by comprising: a ceramic textile fabric layer; and an inorganic coating layer coated on both surfaces of the ceramic textile fabric layer. Accordingly, electrical insulation is excellent, occurrence of thermal runaway transition to other adjacent battery cells can be prevented and delayed even when thermal runaway occurs, and deformation of shape and generation of perforation due to thermal runaway and fire can be prevented owing to excellent flame prevention and heat resistance, thereby continuously maintaining thermal runaway transition delay performance and mechanical strength.

Description

Battery thermal runaway delay and flame retardant pad and battery pack equipped therewith

[0001] The present invention relates to a pad for delaying battery thermal runaway and flame retardancy and a battery pack having the same.

[0002] Recently, devices such as electric vehicles, mobile phones, laptops, and digital cameras are demanding thinner and higher-capacity energy storage devices.

[0003] The energy storage device widely used in the above devices and equipment is a secondary battery, and among them, lithium secondary batteries have the advantage of achieving thinness and high energy density and high output operation.

[0004] Meanwhile, if thinning is possible, it is suitable for implementing a higher capacity battery pack since a large number of lithium secondary batteries can be placed within a limited area.

[0005] However, when connecting multiple lithium secondary batteries, the capacity increases, but there is a problem in that the heat generated when each battery is charged and discharged accumulates between the batteries, which reduces battery performance.

[0006] In addition, if a malfunction or defect in one of the multiple batteries causes high temperature heat to be transmitted to other adjacent batteries, the performance of the entire battery pack may be reduced, and furthermore, if thermal runaway occurs, the thermal runaway may be transmitted to other adjacent batteries, which may cause a fire or explosion in the device equipped with the batteries.

[0007] Accordingly, when multiple batteries are placed in contact with each other, even if thermal runaway occurs in one battery, the transfer of thermal runaway to other adjacent batteries is delayed, and research on thermal runaway delay and flame retardancy that can continuously delay the transfer of thermal runaway by having flame retardant performance and prevent larger explosions and / or fires is urgently needed.

[0008] The present invention has been devised in consideration of the above points, and the purpose of the present invention is to provide a battery thermal runaway delay and flame retardant pad that can prevent and delay heat exchange or heat transfer between adjacent batteries, thereby blocking and delaying the transfer of thermal runaway to another adjacent battery cell even when thermal runaway occurs in one battery cell, and has excellent flame retardancy and heat resistance, so as to continuously maintain the performance of blocking and delaying thermal runaway transfer.

[0009] In addition, another object of the present invention is to provide a battery thermal runaway delay and flame retardant pad that has excellent heat dissipation and heat resistance and can prevent dust from flying due to damage that may occur due to impact.

[0010] In addition, the present invention has another purpose of providing a battery thermal runaway delay and flame retardant pad that can be fixedly placed between adjacent battery cells without a separate adhesive material due to its compressibility and adhesiveness, and can minimize physical collision between battery cells even when subjected to external vibration or shaking.

[0011] Furthermore, another object of the present invention is to provide a battery pack that can prevent an explosion or fire from spreading to the entire battery pack and a device or apparatus including the same even when a thermal runaway or fire occurs in any one battery cell by including a sheet having a thermal runaway delay and flame retardant function.

[0012] In order to solve the above-described problem, the present invention provides a battery thermal runaway delay and flame retardant pad comprising a ceramic fiber fabric monolayer and an inorganic coating layer coated on both sides of the ceramic fiber fabric monolayer.

[0013] According to one embodiment of the present invention, the ceramic fiber fabric layer may be a fabric, knitted fabric or non-woven fabric formed of ceramic fibers containing at least one of alumina, silica and zirconium oxide.

[0014] Additionally, the ceramic fiber fabric layer may be formed of ceramic fibers having a diameter of 1 to 6 μm.

[0015] In addition, the ceramic fiber fabric layer has a porous structure, may have a thickness of 1 to 6 mm, and a basis weight of 200 to 1200 g / ㎡.

[0016] Additionally, the inorganic coating layer may include 28.5 to 35.8 wt% of alumina, 7 to 14 wt% of silica, 42 to 50 wt% of phosphoric acid, and 7 to 14 wt% of monoammonium phosphate.

[0017] Additionally, the average thickness of the above-mentioned inorganic coating layer may be 0.1 to 0.5 mm.

[0018] Additionally, a portion of the thickness of the inorganic coating layer may be located within the ceramic fiber fabric monolayer.

[0019] Additionally, the above-mentioned inorganic coating layer can be formed using an inorganic coating composition having a viscosity of 400 to 520 cP.

[0020]

[0021] In addition, the present invention provides a battery pack including a plurality of battery cells arranged so that one side of the battery cells faces each other, and a thermal runaway delay and flame retardant pad according to the present invention arranged between the facing sides of adjacent battery cells.

[0022] According to one embodiment of the present invention, the device may further include a cooling member disposed on one side so as to be in contact with a plurality of battery cells, and a thermal runaway delay pad integrally covering an externally exposed surface of the plurality of battery cells.

[0023] Additionally, a thermal interface material may be further included between the plurality of battery cells and the cooling member.

[0024]

[0025] In addition, the present invention provides an electric vehicle including a battery pack according to the present invention.

[0026] The battery thermal runaway delay and flame retardant pad according to the present invention has excellent electrical insulation properties and can prevent and delay the spread of thermal runaway to adjacent battery cells even when thermal runaway occurs. In addition, since it has excellent flame retardancy and heat resistance, it prevents deformation and perforation due to thermal runaway and fire, thereby continuously maintaining thermal runaway delay performance and mechanical strength. Furthermore, since it has compressibility and adhesiveness, it can be tightly fixedly arranged between adjacent battery cells without a separate adhesive member. In addition, it can prevent dust from flying that may be generated due to damage or destruction from external impact, thereby preventing new or additional dangerous situations such as fires and explosions caused by dust, and thus it can be widely applied from general electronic devices that use battery packs to electric vehicles.

[0027] FIG. 1 is a cross-sectional view of a battery thermal runaway delay and flame retardant sheet according to one embodiment of the present invention;

[0028] Figure 2 is a cross-sectional schematic diagram and a partially enlarged view of a battery pack according to one embodiment of the present invention.

[0029] Figure 3 is a photograph of a sheet for delaying battery thermal runaway and flame retardancy according to one embodiment of the present invention, and

[0030] Figure 4 shows a photograph of one side of the battery thermal runaway delay and flame retardant sheet of Figure 3 directly exposed to flame after an experiment in which flame was applied to one side of the sheet for 15 minutes.

[0031] Hereinafter, with reference to the attached drawings, embodiments of the present invention will be described in detail so that those skilled in the art can easily implement the present invention. The present invention may be implemented in various different forms and is not limited to the embodiments described herein. In the drawings, parts irrelevant to the description have been omitted for clarity of description, and the same reference numerals are assigned to identical or similar components throughout the specification.

[0032]

[0033] Referring to FIG. 1, a battery thermal runaway delay and flame retardant pad (100) according to one embodiment of the present invention includes a ceramic fiber fabric single layer (110) and an inorganic coating layer (120) coated on both sides of the ceramic fiber fabric single layer (110).

[0034]

[0035] The above ceramic fiber fabric layer (110) has a porous structure formed through ceramic fibers, and through this, exhibits heat resistance, flame retardancy, flame retardancy, heat insulation, insulation, and compressibility, and has excellent flexibility, so that it can contact with excellent adhesion even on a curved battery cell surface.

[0036] The above ceramic fiber fabric layer (110) may be a known fabric implemented through ceramic fibers, and may be, for example, a woven fabric, knitted fabric, or non-woven fabric. In addition, the ceramic fibers constituting the ceramic fiber fabric layer (110) may be long fibers, short fibers, or raw cotton.

[0037] The above ceramic fiber may contain one or more of alumina, silica, and zirconium oxide.

[0038] In addition, in order to enhance the thermodynamic properties of the ceramic fiber or the ceramic fiber fabric layer (110) formed therefrom, such as high temperature resistance, slag resistance, thermal shock resistance, and stability at high temperatures and in a vacuum, the ceramic fiber or the ceramic fiber fabric layer (110) may further include a thermal property improving material including an oxide of an alkali metal or alkaline earth metal. The thermal property improving material may include, for example, one or more of calcium oxide, magnesium oxide, and strontium oxide.

[0039] For example, the ceramic fiber fabric layer (110) may be a fabric that includes 62 to 80 wt% of silica, 18 to 39 wt% of a thermal property improving material composed of magnesium oxide and calcium oxide, a binder, and other additives, and has a maximum use temperature of 1100 to 1300°C. Or, as another example, the ceramic fiber fabric layer (110) may be a fabric that includes 40 to 50 wt% of alumina, 59 to 49 wt% of silica, a binder, and other additives, and has a maximum use temperature of 1260 to 1350°C.

[0040] In addition, the ceramic fiber may have an average diameter of 1 to 6 μm, more preferably 1.5 to 6 μm, which may be advantageous in achieving the purpose of the present invention.

[0041]

[0042] In addition, the ceramic fiber fabric layer (110) may have a porous structure, a thickness of 1 to 6 mm, and a basis weight of 200 to 1200 g / ㎡, thereby providing sufficient compressibility and flexibility, and the air within the pores may be advantageous in enhancing the insulating effect while providing sufficient mechanical strength and thermal shock and heat resistance.

[0043]

[0044] An inorganic coating layer (120) is disposed on both sides of the above-described ceramic fiber fabric layer (110), and provides non-combustibility to the thermal runaway delay and flame retardant pad (100). In addition, the inorganic coating layer (120) can function as a layer to prevent dust from flying away that may be generated from the ceramic fiber fabric layer (110). Specifically, the ceramic fiber fabric layer (110) may be damaged, such as broken, by external force due to the material properties of the main ceramic component and the fine diameter of the ceramic fibers, and there is a concern that dust may fly away as a result. Dust flying away from within the battery pack may contaminate the device and cause malfunction of electronic components, thereby causing problems such as lowering the performance of the battery pack. However, the inorganic coating layer (120) can prevent dust from flying away to the outside even if it is generated by the ceramic fiber fabric layer (110) by covering both sides of the ceramic fiber fabric layer (110) with a predetermined thickness.

[0045]

[0046] In addition, the inorganic coating layer (120) may include components having incombustibility, fire resistance, and flame retardancy properties in order to exhibit incombustibility. For example, the inorganic coating layer (120) may include 28.5 to 35.8 wt% of alumina, 7 to 14 wt% of silica, 42 to 50 wt% of phosphoric acid, and 7 to 14 wt% of ammonium phosphate monobasic, and thereby may be advantageous in achieving the purpose of the present invention. In this case, as an example, the contained phosphoric acid component may absorb moisture present in the air when exposed to the air at room temperature, thereby exhibiting a certain level or more of tackiness on the surface of the inorganic coating layer (120) without an adhesive agent, and thus, the surface tackiness of the inorganic coating layer may be used to closely fix the battery cell surface without a separate adhesive layer or adhesive member.

[0047]

[0048] In addition, the average thickness of the inorganic coating layer (120) may be 0.1 to 0.5 mm, which may be advantageous in terms of durability while sufficiently expressing the intended function. If the average thickness exceeds 0.5 mm, there is a concern that cracks may occur or detachment may occur in the inorganic coating layer (120), and the improvement in non-flammability performance may be minimal. In addition, if the average thickness is less than 0.1 mm, the improvement in non-flammability performance may be minimal and it may be difficult to express tackiness. Meanwhile, as illustrated in FIG. 1, the inorganic coating layer (120) may have a region corresponding to a portion of the thickness (d) located within the ceramic fiber fabric layer (110). This can occur when the solution forming the inorganic coating layer penetrates through the pores on the surface of the ceramic fiber monolayer (110) during the formation process of the inorganic coating layer (120). Since a region corresponding to a certain thickness (d) is located within the ceramic fiber monolayer (110), the detachment of the inorganic coating layer (120) is minimized, which is advantageous. However, if the region thickness of the inorganic coating layer (120) located within the ceramic fiber monolayer (110) increases, the flexibility and compressive properties may deteriorate due to pore blockage of the ceramic fiber monolayer (110), and the damage to the inorganic coating layer (120) may increase due to the compression of the ceramic fiber monolayer (110), which may be undesirable. Therefore, it may be advantageous for the region thickness (d) of the inorganic coating layer (120) located within the ceramic fiber monolayer (110) to have a thickness of 1 / 10 to 1 / 20 of the thickness of the ceramic fiber monolayer (110).

[0049]

[0050] In addition, the inorganic coating layer (120) can be implemented by treating an inorganic coating layer forming solution on the ceramic fiber fabric monolayer (110). The inorganic coating layer forming solution can include, for example, 20 to 25 wt% of alumina, 5 to 10 wt% of silica, 30 to 35 wt% of phosphoric acid, 5 to 10 wt% of ammonium phosphate monobasic, and a dispersion medium such as the balance of water. In addition, the inorganic coating layer forming solution can have a viscosity of 400 to 520 cP, which is advantageous in forming a coating layer with a predetermined thickness on the surface of the ceramic fiber fabric monolayer (110) while minimizing or controlling the inflow into the pores of the surface of the ceramic fiber fabric monolayer (110) to an appropriate level.

[0051]

[0052] Meanwhile, the battery thermal runaway delay and flame retardant pad (100) according to one embodiment of the present invention may not further include a separate adhesive layer or adhesive member. Conventional polymer-based adhesive layers or adhesive members are easily deteriorated in the event of thermal runaway and fire generated in a battery cell, thereby weakening the adhesive properties between the battery cell and the battery thermal runaway delay and flame retardant pad (100). In this case, it may be difficult for the battery thermal runaway delay and flame retardant pad (100) to be properly fixed to one surface of the battery cell, and thus it may be difficult to delay the transfer of the generated thermal runaway.

[0053]

[0054] Referring to FIG. 2, the present invention can be implemented as a battery pack (1000) equipped with the above-described battery thermal runaway delay and flame retardant pad (100). Specifically, the battery pack (1000) includes a plurality of battery cells (10) arranged so that one side faces each other, and thermal runaway delay and flame retardant pads (100) arranged between the facing sides of adjacent battery cells (10).

[0055] The battery cell (10) above can be used without limitation as a known battery cell having an electrode assembly in which at least one positive electrode and a negative electrode are laminated with a separator in between, an electrolyte, and a case for accommodating them. The battery cell (10) can be, for example, a lithium-ion cell. In addition, the battery cell (10) can have an exterior material that is a hardened metal, a plastic case, or a composite of a metal layer and a polymer resin film layer. In addition, the positive electrode and the negative electrode of the battery cell (10) can use known electrode materials without limitation, and a known positive electrode active material and a negative electrode active material can be coated on the positive electrode and the negative electrode. In addition, the electrolyte of the battery cell (10) can use a known electrolyte such as a lithium-ion electrolyte or a polymer electrolyte, and therefore the present invention is not particularly limited thereto. In addition, the shape of the battery cell (10) may be a cylindrical shape, or may have a known pouch-type battery shape in which the electrode assembly is accommodated inside a pouch-type outer material and the outer material rim surrounding the electrode assembly is compressed.

[0056] The above battery cells (10) can be arranged with their surfaces facing each other so that the maximum number of cells can be arranged in a limited space.

[0057]

[0058] The above-described battery thermal runaway delay and flame retardant pad (100) is placed between battery cells (10) whose surfaces are arranged to face each other. At this time, the battery thermal runaway delay and flame retardant pad (100) may be placed to contact the entire surface or a portion of one surface of the battery cell (10), but may preferably be placed to cover the entire surface. In addition, the battery thermal runaway delay and flame retardant pad (100) may be placed between all battery cells (10) provided in the battery pack (1000), or may be provided only between some adjacent battery cells (10).

[0059]

[0060] Additionally, the battery pack (1000) may further include a cooling member (200, 300) arranged on one side so as to come into contact with a plurality of battery cells (10) being arranged.

[0061] The above cooling member (200, 300) may include, for example, a cooling plate (200) for supporting a plurality of battery cells (10) and transferring heat generated therefrom to the outside, and a cooling pipeline (300) for transferring heat transferred to the cooling plate (200) to the outside through a refrigerant flowing inside.

[0062]

[0063] In addition, the battery pack (1000) may further include a thermal runaway delay pad (400) that integrally covers the externally exposed surfaces of a plurality of battery cells (10). The thermal runaway delay pad (400) serves to delay the transfer of thermal runaway generated in one or more battery cells (10) to the outside of the battery pack (1000), and any thermal runaway delay pad known in the battery field may be used without limitation. In addition, it is to be noted that the thermal runaway delay and flame retardant sheet according to the present invention described above may be used as the thermal runaway delay pad (400).

[0064]

[0065] In addition, the battery pack (1000) may further include a thermal interface material (500) disposed between the plurality of battery cells (10) and the cooling member (200, 300). Even when the cooling member (200, 300) is disposed on one side of the plurality of battery cells (10), an empty space may exist at the interface between the battery cells (10) and the cooling member (200, 300), and this empty space may function as an insulating layer, making it difficult for the heat generated from the battery cells (10) to be smoothly transferred to the cooling member (200, 300). Accordingly, a thermal interface material (500) disposed between the battery cells (10) and the cooling member (200, 300) is disposed, and the thermal interface material (500) may be used without limitation as long as it is a known material used to prevent a deterioration in the thermal conductivity characteristics of the interface. For example, the heat transfer material (500) may include a plurality of heat conductive fillers (501) dispersed within a matrix component (502) capable of filling an interface.

[0066] The present invention will be described in more detail through the following examples, but the following examples do not limit the scope of the present invention, and should be interpreted as helping to understand the present invention.

[0067]

[0068] <Example 1>

[0069] A ceramic fabric layer, which is a ceramic paper having a thickness of 3 mm and a basis weight of 600 g / ㎡ and is formed of ceramic fibers having a diameter of 1.5 to 5 ㎛ containing 46 wt% alumina and 53 wt% silica, was prepared. An inorganic coating layer containing 33 wt% alumina, 10 wt% silica, 50% phosphoric acid, and 7 wt% ammonium phosphate monobasic was formed on both sides of the prepared ceramic fabric layer to a thickness of 0.25 mm to manufacture a pad for delaying thermal runaway and retarding flames in a battery. The inorganic coating layer was implemented by treating an inorganic coating layer forming solution having a viscosity of 480 cP, in which 23 wt% alumina, 7 wt% silica, 35% phosphoric acid, and 5 wt% ammonium phosphate monobasic were mixed with the remainder of water, and then drying the solution.

[0070]

[0071] <Experimental Example>

[0072] After applying a torch flame to the battery thermal runaway delay and flame retardant pad according to Example 1 for 15 minutes, the entire surface of the battery thermal runaway delay and flame retardant pad was observed with the naked eye and an optical microscope to observe whether ceramic powder was scattered, whether the inorganic coating layer was cracked or peeled, and whether the sheet surface was perforated. Photos taken before and after the evaluation are shown in Figures 3 and 4.

[0073]

[0074] Specifically, as can be confirmed through Figures 3 and 4, the evaluation results showed that there was no scattering of ceramic powder, no damage such as cracks or peeling of the inorganic coating layer, and no perforation occurred on the sheet surface.

[0075]

[0076] Although one embodiment of the present invention has been described above, the spirit of the present invention is not limited to the embodiment presented in this specification, and a person skilled in the art who understands the spirit of the present invention will be able to easily propose other embodiments by adding, changing, deleting, or adding components within the scope of the same spirit, but this will also be considered to fall within the spirit of the present invention.

Claims

1. Ceramic fiber single layer; and A pad for delaying and retardant-fighting battery thermal runaway, comprising an inorganic coating layer coated on both sides of the ceramic fiber fabric layer.

2. In paragraph 1, The above ceramic fiber fabric layer is a woven, knitted or non-woven pad for battery thermal runaway delay and flame retardancy formed of ceramic fibers containing at least one of alumina, silica and zirconium oxide.

3. In paragraph 1, The above ceramic fiber fabric layer is a battery thermal runaway delay and flame retardant pad formed of ceramic fibers having a diameter of 1 to 6㎛.

4. In paragraph 1, The above ceramic fiber fabric layer has a porous structure, a thickness of 1 to 6 mm, and a basis weight of 200 to 1200 g / ㎡, and is a pad for delaying thermal runaway and retardant of a battery.

5. In paragraph 1, A battery thermal runaway delay and flame retardant pad comprising the above inorganic coating layer comprising 28.5 to 35.8 wt% of alumina, 7 to 14 wt% of silica, 42 to 50 wt% of phosphoric acid, and 7 to 14 wt% of monoammonium phosphate.

6. In paragraph 1, A pad for delaying battery thermal runaway and flame retardancy, wherein the average thickness of the above-mentioned inorganic coating layer is 0.1 to 0.5 mm.

7. In paragraph 1, A battery thermal runaway delay and flame retardant pad, wherein a portion of the thickness of the inorganic coating layer is located within the ceramic fiber fabric monolayer.

8. In paragraph 1, A battery thermal runaway delay and flame retardant pad, wherein the above-mentioned inorganic coating layer is formed using an inorganic coating composition having a viscosity of 400 to 520 cP.

9. A plurality of battery cells arranged so that one side faces the other; and A battery pack comprising a thermal runaway delay and flame retardant pad according to claim 1, which is disposed between facing surfaces of adjacent battery cells.

10. In paragraph 9, A cooling member arranged on one side so as to come into contact with a plurality of battery cells being arranged; and A battery pack further comprising a thermal runaway delay pad that integrally covers the externally exposed surfaces of a plurality of battery cells.

11. In paragraph 10, A battery pack further comprising a thermal interface material disposed between a plurality of battery cells and a cooling member.

12. An electric vehicle comprising a battery pack according to Article 9.

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