Battery pack

Abstract

A battery pack includes: a case; a battery cell accommodated in the case at an upper position in a gravity direction; a gas outlet located between the battery cell and the case at a lower position in the case and facing an exhaust portion of the battery cell; and a fire prevention and extinguishment layer between the battery cell and the gas outlet.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to and the benefit of Korean Patent Application No. 10-2023-0039399 filed on March 26, 2023, and Korean Patent Application No. 10-2023-0107857 filed on August 17, 2023, in the Korean Intellectual Property Office, the entire contents of which are incorporated herein by reference. Technical Field

[0003] Aspects of embodiments of the present disclosure relate to a battery pack. Background Art

[0004] Lithium batteries generally refer to batteries that use various types of lithium compounds. Lithium batteries are used in various ways because they have higher energy density than lead-acid batteries. A battery pack includes multiple battery cells. Battery packs have been widely used in home appliances, electric vehicles, hybrid vehicles, etc.

[0005] The battery pack may overheat due to electrical shock or physical shock in the charge / discharge of the battery cells, and a fire or explosion may occur due to overheating. If an event caused by overheating occurs in any one cell of a battery pack including a plurality of battery cells, the heat needs to be effectively blocked before it is transferred to nearby cells. To this end, the cells in the battery pack may include an exhaust portion for discharging heat and gas generated due to the event to the outside of the cell. If the fire or flame discharged through the exhaust portion is transferred to the adjacent cell, a large fire or explosion may occur.

[0006] For example, compared to the currently widely used 21700 battery cells, if a thermal runaway event occurs, the newly designed 4680 battery cells may generate six times the heat generated by the 21700 battery cells. The polyurethane foam potting structure used as a heat dissipation structure in the related art has a heat resistance of 150°C, but needs to be improved because if a fire occurs inside the battery pack, high heat of about 500°C or higher is generated. Utility Model Content

[0007] Embodiments of the present disclosure include a battery pack having an improved internal structure to effectively prevent heat from being propagated to nearby cells when a fire occurs in one cell.

[0008] Additional aspects and features will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the embodiments described in the present disclosure.

[0009] According to one embodiment of the present disclosure, a battery pack includes: a shell; a battery cell accommodated in the shell at an upper position in the gravity direction; a gas outlet located at a lower position in the shell between the battery cell and the shell and facing an exhaust portion of the battery cell; and a fire-proof and fire-extinguishing layer between the battery cell and the gas outlet.

[0010] The fire-proofing and fire-extinguishing layer may include a fire-retardant coating.

[0011] The fire blocking layer may be configured to expand when exposed to a certain temperature to block the introduction of air into the ignition site.

[0012] The vent portion may be at a lower end portion of the battery cell.

[0013] The battery pack may further include a heat insulating member between the battery cell and the gas outlet.

[0014] The fire protection and extinguishing layer may be on the thermal insulation member.

[0015] The fire-preventing and extinguishing layer may be on an inner surface of the thermal insulation member, and the inner surface may face the battery cells.

[0016] The fire-preventing and extinguishing layer may be on an outer surface of the thermal insulation member, and the outer surface may be opposite to the battery cell.

[0017] The battery cell may be a cylindrical battery cell having a circular cross-section.

[0018] The battery cell may be a prismatic battery cell, the battery pack may further include a cooling plate disposed below the battery cell, the gas outlet may be between the battery cell and the cooling plate, and the fire extinguishing layer may be below the battery cell to cover the exhaust portion. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The above and other aspects and features of the embodiments of the present disclosure will become more apparent from the following description taken in conjunction with the accompanying drawings, in which:

[0020] Figure 1 shows a cross-sectional structure of a battery pack according to an embodiment of the present disclosure;

[0021] Figure 2 shows a cross-sectional structure of a battery pack according to another embodiment of the present disclosure;

[0022] Figure 3 shows a cross-sectional structure of a battery pack according to another embodiment of the present disclosure;

[0023] Figure 4Schematically showing when Figure 1 When an event occurs inside the battery pack shown in FIG, the fire-proof and fire-extinguishing layer blocks the flame from spreading to nearby cells;

[0024] Figure 5 Schematically showing when Figure 1 When an incident occurs inside the battery pack shown in FIG, the fire-proof and fire-extinguishing layer is foamed to prevent the flame from spreading to nearby cells;

[0025] Figure 6 Schematically showing when Figure 1 When an event occurs inside the battery pack shown in , the battery cells are supported and heat is conducted to the housing due to the foaming of the fire-proof and fire-extinguishing layer; and

[0026] Figure 7 The structure of a battery pack including a prismatic battery cell according to other embodiments of the present disclosure is shown. DETAILED DESCRIPTION

[0027] Reference will now be made in detail to embodiments, examples of which are illustrated in the accompanying drawings. In this regard, the described embodiments may have different forms and should not be construed as being limited to the descriptions set forth herein. Accordingly, embodiments are only described below with reference to the accompanying drawings to explain aspects and features of the present description.

[0028] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings to allow those of ordinary skill in the art to easily perform embodiments of the present disclosure. However, the present disclosure may be implemented in various different forms and is not limited to the embodiments described herein. In addition, when describing embodiments of the present disclosure in detail, when it is determined that a detailed description of related known functions or configurations may unnecessarily obscure the main points of the present disclosure, such detailed description may be omitted.

[0029] It will be understood that when an element or layer is referred to as being "on," "connected to," or "coupled to" another element or layer, it may be directly on, connected to, or coupled to the other element or layer, or there may also be one or more intervening elements or layers. When an element or layer is referred to as being "directly on," "directly connected to," or "directly coupled to" another element or layer, there may be no intervening elements or layers. For example, when a first element is described as being "coupled to" or "connected to" a second element, the first element may be directly coupled to or connected to the second element, or the first element may be indirectly coupled to or connected to the second element via one or more intervening elements.

[0030] In the accompanying drawings, for the sake of illustration, the sizes of various elements, layers, etc. may be exaggerated. The same reference numerals represent the same elements. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items. In addition, when describing the embodiments of the present disclosure, the use of "may" relates to "one or more embodiments of the present disclosure". When the expressions such as "at least one of ..." and "any one of ..." are after the element list, the entire element list is modified without modifying the single element of the list. For example, the expression "at least one of a, b and c" means only a, only b, only c, both a and b, both a and c, both b and c, all of a, b and c or its variant. As used herein, the terms "use" and "used" may be considered to be synonymous with the terms "utilize" and "utilized", respectively. As used herein, the terms "substantially", "about" and similar terms are used as approximate terms rather than as degree terms, and are intended to take into account the inherent deviations in the measured or calculated values ​​that will be recognized by those of ordinary skill in the art.

[0031] It will be understood that although the terms first, second, third, etc. can be used in this article to describe various elements, components, regions, layers and / or sections, these elements, components, regions, layers and / or sections should not be limited by these terms. These terms are used to distinguish one element, component, region, layer or section from another element, component, region, layer or section. Therefore, without departing from the teachings of the exemplary embodiments, the first element, component, region, layer or section discussed below can be referred to as a second element, component, region, layer or section.

[0032] For ease of description, spatial relative terms such as "below", "below", "down", "above", "on", etc. can be used in this article to describe the relationship between an element or feature and another element or feature as illustrated in the figure. It will be understood that, in addition to the orientation depicted in the figure, the spatial relative terms are intended to cover different orientations of the device in use or operation. For example, if the device in the figure is turned over, the element described as "below" or "below" other elements or features will then be oriented "above" or "on" other elements or features. Therefore, the term "below" can cover both upper and lower orientations. The device can be oriented in other ways (rotated 90 degrees or in other orientations), and the spatial relative descriptors used in this article should be interpreted accordingly.

[0033] The terms used herein are for the purpose of describing the embodiments of the present disclosure and are not intended to limit the present disclosure. As used herein, the singular "a" is intended to also include the plural form, unless the context clearly states otherwise. It will be further understood that the terms "comprising" and / or "including" when used in this specification clearly indicate the presence of stated features, integers, steps, operations, elements and / or parts, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, parts and / or their groups.

[0034] Figure 1 A cross-sectional structure of a battery pack according to an embodiment of the present disclosure is shown. Figure 2 A cross-sectional structure of a battery pack according to another embodiment of the present disclosure is shown. Figure 3 A cross-sectional structure of a battery pack according to another embodiment of the present disclosure is shown. Figure 4 Schematically showing when Figure 1 When an incident occurs inside the battery pack shown in the figure, the fire-resistant layer prevents the flame from spreading to nearby cells. Figure 5 Schematically showing when Figure 1 When an incident occurs inside the battery pack shown in the figure, the fire-proof and fire-extinguishing layer is foamed to prevent the flame from spreading to nearby cells. Figure 6 Schematically showing when Figure 1 When an event occurs inside the battery pack shown in FIG, the fire-resistant and fire-extinguishing layer foams to support the battery cells and induce heat conduction to the casing. Figure 7 The structure of a battery pack including a prismatic battery cell according to other embodiments of the present disclosure is shown.

[0035] refer to Figure 1 to Figure 6 According to an embodiment of the present disclosure, the battery pack 10 may include a housing 20, a battery cell 30, a cell fixing mold 40, a gas outlet 50, and a fire extinguishing layer 60. In some embodiments, as Figure 2 and Figure 3 As shown, the battery pack 10 may further include a heat insulating member 70 .

[0036] The case 20 may be a structure having a space therein. The case 20 may be manufactured by using a metal material such as aluminum, iron, etc. The case 20 may be a structure that accommodates a battery cell 30 described later.

[0037] The housing 20 may have, for example, a rectangular parallelepiped box shape.

[0038] The battery cell 30 may be mounted inside the housing 20. The battery cell 30 may be a cylindrical battery cell having a circular cross section. A plurality of battery cells 30 may be provided inside the housing 20. The battery cell 30 may be arranged upward in the housing 20 in the direction of gravity. For example, the battery cell 30 may be accommodated in the housing 20 at an upper position in the direction of gravity. The battery cell 30 may be arranged so that its upper portion is fixed to the housing 20. The battery cell 30 may be fixed to the upper portion of the housing 20 by a cell fixing mold 40, which may be made of a synthetic resin. A bus bar electrically connecting a plurality of battery cells 30 together may be coupled to the cell fixing mold 40. An insulator 45 may be arranged between the cell fixing mold 40 and the housing 20 to maintain an electrically insulating state.

[0039] The battery cell 30 may include a vent portion. The vent portion may be a structure that discharges gas to the outside of the battery cell 30 if gas or heat is generated inside the battery cell 30. The vent portion may be configured to discharge gas downward from the battery cell 30. For example, the vent portion may be formed at a lower end portion of the battery cell 30.

[0040] The gas outlet 50 may be formed between the battery cell 30 and the case 20 at a lower position in the case 20. The gas outlet 50 may be disposed below the battery cell 30 to face a venting portion of the battery cell 30. The gas outlet 50 may be a space formed between a lower end portion of the battery cell 30 and the case 20.

[0041] A fire-proofing and fire-extinguishing layer 60 may be formed between the battery cell 30 and the gas outlet 50. The fire-proofing and fire-extinguishing layer 60 may include a fire-proofing paint.

[0042] The fire-proof and fire-extinguishing layer 60 may have a high-temperature foaming property to block the introduction of air into the ignition site. For example, the fire-proof and fire-extinguishing layer 60 may expand in a range of about 80 to about 100 times while producing carbonized substances and non-combustible gases at a temperature of about 250°C or higher. The fire-proof and fire-extinguishing layer 60 may begin to foam after burning for about 10 minutes or more, and may be completely foamed after about 30 minutes or more. The thermal conductivity of the fire-proof and fire-extinguishing layer 60 before foaming is in the range of about 0.1Kcal / mh°C to about 0.3Kcal / mh°C, and the thermal conductivity after foaming is in the range of about 0.01Kcal / mh°C to about 0.03Kcal / mh°C. Even if the fire-proof and fire-extinguishing layer 60 is not foamed, the fire-proof and fire-extinguishing layer 60 has a thermal conductivity at a level similar to that of the mica sheet currently used in the battery pack of the related art, so that the thermal insulation performance of the mica level can be expected when the combustion starts. If the battery pack 10 catches fire, the effect of the fire extinguishing layer 60 may exceed the effect of the aerogel (e.g., be greater than the effect of the aerogel). Even if the fire extinguishing layer 60 is applied at a thickness of about 0.5 mm, the fire extinguishing layer 60 may be thickened to a level of about 10 times its initial thickness after foaming, thereby ensuring sufficiently high thermal insulation performance from the exhaust portion of the cell to the shell. The fire extinguishing layer 60 may be applied to prismatic battery cells as well as cylindrical battery cells. The fire extinguishing layer 60 may have a form that covers (e.g., may cover) the exhaust portion of the battery cell 30.

[0043] The heat insulating member 70 may be arranged between the battery cell 30 and the gas outlet 50. The heat insulating member 70 may include a fire extinguishing layer 60. The fire extinguishing layer 60 may be formed on the heat insulating member 70. For example, the fire extinguishing layer 60 may be formed on the inner surface of the heat insulating member 70, wherein the inner surface of the heat insulating member 70 faces the battery cell 30. The fire extinguishing layer 60 may be formed on the outer surface of the heat insulating member 70, wherein the outer surface of the heat insulating member 70 is opposite to the battery cell 30 (e.g., facing away from the battery cell 30).

[0044] Hereinafter, the working effects of the battery pack 10 including at least some of the components described above will be described using an example of a combustion event occurring in the battery cell 30 of the battery pack 10 .

[0045] refer to Figure 4 If a combustion event occurs in any battery cell 30 in the battery pack 10, and even if a flame breaks out at the gas outlet 50 formed below the exhaust portion, due to the thermal insulation effect of the fire-proof and fire-extinguishing layer 60, the flame can disappear through the gas outlet 50 without spreading to the nearby battery cells 30.

[0046] refer to Figure 5If a combustion event occurs in any one of the battery cells 30 in the battery pack 10, the fire extinguishing layer 60 may expand at (e.g., when exposed to) a high temperature of about 300° C. or higher, so that a heat absorption effect may be performed and the internal heat energy of the battery pack 10 may be reduced. The fire extinguishing layer 60 having an expanded volume may form a carbonized layer and may prevent air introduction by forming an annular structure.

[0047] refer to Figure 6 If a combustion event occurs in any one of the battery cells 30 in the battery pack 10, the fire-proofing and fire-extinguishing layer 60 may expand at a high temperature to transfer (or guide) heat to or toward the housing 20, thereby forming a heat dissipation path. Even if the cell fixing mold 40 arranged on the battery cell 30 collapses due to the high temperature of the combustion, the fire-proofing and fire-extinguishing layer 60 may expand to support the lower end portion of the battery cell 30, thereby preventing the collapse of the arrangement structure of the battery cell 30.

[0048] Figure 7 is a cross-sectional view of a battery pack showing a structure according to another embodiment of the present disclosure. Figure 7 , a plurality of prismatic battery cells 30 may be arranged to be electrically connected to each other inside the housing 20. A cooling plate 80 may be arranged below the battery cell 30. An insulator 45 may be arranged between the cooling plate 80 and the lower end portion (or lower surface) of the battery cell 30. A gas outlet 50 may be provided between the lower end portion of the battery cell 30 and the cooling plate 80. A fire extinguishing layer 60 may be formed to cover the exhaust portion below the battery cell 30. If a fire event occurs in any one of the battery cells 30, the flame may be effectively blocked from propagating to nearby cells by the fire extinguishing layer 60. The fire extinguishing layer 60 may expand at high temperatures to provide heat absorption and block air introduction.

[0049] As described above, in the battery pack according to the embodiment of the present disclosure, the fire-resistant and fire-extinguishing layer can withstand high heat of about 1000° C. or higher, thereby blocking the heat from propagating to nearby cells even if combustion occurs in one cell.

[0050] If a fire occurs, the fire extinguishing layer can provide heat absorption by expanding at high temperatures, thereby reducing the internal temperature of the battery pack during the event.

[0051] Even if the mold for supporting the battery cell collapses, the fire extinguishing layer can support the battery cell by expanding at high temperature.

[0052] Although the present disclosure has been described in detail with respect to the embodiments of the present disclosure, the present disclosure is not limited to the above embodiments. It is obvious that within the technical spirit of the present disclosure, a person skilled in the art can make many modifications.

[0053] It should be understood that the embodiments described herein should be considered in a descriptive sense and not for limiting purposes. The description of features or aspects within each embodiment should generally be considered to be applicable to other similar features or aspects in other embodiments. Although one or more embodiments have been described with reference to the accompanying drawings, it will be understood by those of ordinary skill in the art that various changes in form and detail may be made therein without departing from the spirit and scope of the present disclosure as defined by the appended claims and their equivalents.

Claims

1. A battery pack, characterized in that: The battery pack comprises: case; a battery cell accommodated in the housing at an upper position in the direction of gravity; a gas outlet located between the battery cell and the case at a lower position in the case and facing a gas exhaust portion of the battery cell; and A fire-proof and fire-extinguishing layer is provided between the battery cells and the gas outlet.

2. The battery pack according to claim 1, characterized in that: The fire-proof and fire-extinguishing layer comprises a fire-proof coating.

3. The battery pack according to claim 1, characterized in that: The fire blocking layer is configured to expand when exposed to a certain temperature to block the introduction of air into the ignition site.

4. The battery pack according to claim 1, characterized in that: The vent portion is at a lower end portion of the battery cell.

5. The battery pack according to claim 1, characterized in that: The battery pack further includes a heat insulating member between the battery cell and the gas outlet.

6. The battery pack according to claim 5, characterized in that: The fire-proofing and fire-extinguishing layer is on the thermal insulation component.

7. The battery pack according to claim 6, characterized in that: The fire-proofing and extinguishing layer is on an inner surface of the thermal insulation member, the inner surface facing the battery cells.

8. The battery pack according to claim 6, characterized in that: The fire-proofing and fire-extinguishing layer is on an outer surface of the thermal insulation member, the outer surface being opposite to the battery cell.

9. The battery pack according to claim 1, characterized in that: The battery cell is a cylindrical battery cell having a circular cross-section.

10. The battery pack according to claim 1, characterized in that: The battery cell is a prismatic battery cell, the battery pack further includes a cooling plate disposed below the battery cell, the gas outlet is between the battery cell and the cooling plate, and the fire extinguishing layer is below the battery cell to cover the exhaust portion.

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