Battery pack and fire-extinguishing method for battery pack

Abstract

To provide a battery pack and a fire-extinguishing method for a battery pack.SOLUTION: A battery pack according to an example of the present invention includes a battery housing that accommodates a plurality of battery cells, a battery cell accommodation space part in which the battery cells are accommodated in the battery housing, a lower space part disposed on a lower side of the battery cell accommodation space part in the battery housing, and a battery cell base part formed between the lower space part and the battery cell accommodation space part and supporting the battery cells. The battery cell base part includes a base melting part that melts when a heat of more than or equal to a preset temperature is generated in the battery cell, and a base non-melting part that does not melt when the heat of more than or equal to the preset temperature is generated in the battery cell.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] SUMMARY OF THE DISCLOSURE Embodiments of the present invention relate to a battery pack including a fire suppression system and a method for suppressing a fire in a battery pack. [Background technology]

[0002] Generally, a secondary battery is a battery that can be charged and discharged, unlike a primary battery that cannot be charged. Secondary batteries are used as energy sources for mobile devices, electric vehicles, hybrid vehicles, electric bicycles, uninterruptible power supplies, etc., and are used in the form of a single cell or a pack in which multiple batteries are connected together to form a single unit, depending on the type of external device to which they are applied.

[0003] Small mobile devices such as mobile phones can operate for a certain period of time with the output and capacity of a single cell, but when long-term operation or high-power operation is required, such as in electric vehicles and hybrid vehicles that consume a lot of power, a pack configuration containing multiple batteries is preferred due to output and capacity issues, and the output voltage and output current can be increased depending on the number of built-in batteries.

[0004] In general, an immersion method is used as a fire extinguishing system for preventing a thermal runway phenomenon occurring in a battery cell. The immersion method is a system for extinguishing thermal runaway by immersing a battery cell in which thermal runaway occurs in a fire extinguishing liquid.

[0005] A battery pack including a typical fire extinguishing system is shown in Fig. 1. Referring to Fig. 1, the battery pack including a typical fire extinguishing system has a pipe 4a into which cooling water 4 flows for water cooling of the water cooling system of the battery pack, and a separate pipe 3a into which extinguishing liquid 3 flows for the fire extinguishing system of the battery pack.

[0006] In this case, in order to configure the water cooling system and the fire extinguishing system separately, not only a pipe 4a into which cooling water flows for water cooling and a pipe 3a into which fire extinguishing liquid flows, but also a separate cooling water 4 for water cooling and a separate fire extinguishing liquid 3 for fire extinguishing are required, which may complicate the internal structure of the battery pack.

[0007] If the water cooling system and the fire extinguishing system are configured separately in this manner, the volume occupied by the fire extinguishing system will be large and the weight of the battery pack will be heavy, which may reduce the energy density of the battery pack. Summary of the Invention [Problem to be solved by the invention]

[0008] An object of the present invention is to provide a battery pack including a plurality of battery cells, which can efficiently extinguish a fire through a compact structure when a thermal runway occurs in a battery cell.

[0009] However, such problems are merely examples, and the problems that the present invention is intended to solve are not limited to these. [Means for solving the problem]

[0010] A battery pack according to one embodiment of the present invention includes a battery housing that accommodates a plurality of battery cells; a battery cell accommodating space within the battery housing in which the plurality of battery cells are accommodated; a lower space portion disposed below the battery cell accommodating space within the battery housing; and a battery cell base portion formed between the lower space portion and the battery cell accommodating space portion and supporting the plurality of battery cells; the battery cell base portion includes a base melting portion that melts when heat equal to or greater than a predetermined temperature is generated in the battery cell; and a base non-melting portion that does not melt when heat equal to or greater than a predetermined temperature is generated in the battery cell.

[0011] The base non-meltable portion may include a first base non-meltable portion in contact with a lower end of the battery cell; and a second base non-meltable portion spaced apart from the battery cell, and the base non-meltable portion may be disposed between the first base non-meltable portion and the second base non-meltable portion.

[0012] The height of the base molten portion adjacent to the first base unmelted portion is lower than the height of the base molten portion adjacent to the second base unmelted portion.

[0013] An end of the first base unmeltable portion may be formed at a termination point of a rounded corner of a lower end of the battery cell.

[0014] The base molten portion includes a molten portion first width, which is a width at a portion corresponding to a narrow width portion of the battery cell placed on the base non-molten portion, and a molten portion second width, which is a width at a portion corresponding to a wide width portion of the battery cell placed on the base non-molten portion, and the molten portion first width and the molten portion second width are variable.

[0015] A method for extinguishing a fire in a battery pack according to one embodiment of the present invention includes a step of: a thermal runaway occurring in a battery cell; a step of melting a base melting portion adjacent to the battery cell; and a step of immersing the battery cell in the cooling water while the cooling water flows into the battery cell accommodating space through a portion where the base melting portion is located.

[0016] Other aspects, features, and advantages in addition to those described above will become apparent from the following detailed description, claims, and drawings. Effect of the Invention

[0017] A battery pack and a fire extinguishing method for a battery pack according to an embodiment of the present invention include a configuration in which a water cooling system and a fire extinguishing system are combined into one system. That is, a base melting part at a lower end of a battery cell is formed to melt when a thermal runaway occurs in the battery cell, and while the base melting part melts when a thermal runaway occurs in the battery cell, the cooling water in the lower space is filled up to a battery cell receiving space in which the battery cell is arranged, and the battery cell is immersed in the battery pack, thereby performing a battery fire extinguishing function.

[0018] As a result, by using the water cooling system of the battery pack to perform the fire extinguishing function of the battery pack in an emergency, the internal structure of the battery pack can be made compact, the number of parts placed inside the battery pack can be reduced, the volume and weight occupied by the parts can be reduced, and the energy density of the battery pack can be generally improved.

[0019] The effects of the present invention are not limited to the effects described above, and other effects not mentioned will be clearly understood by those skilled in the art from the description of the claims. [Brief description of the drawings]

[0020] [Figure 1] 1 is a cross-sectional view of a battery pack that typically includes a fire suppression system. [Diagram 2] 1 is a perspective view showing a battery pack according to an embodiment of the present invention; [Diagram 3] 3 is a cross-sectional view taken along line AA' of FIG. 2, illustrating a state of a battery pack before thermal runaway according to an embodiment of the present invention. [Figure 4] 4 is an enlarged view of part C in FIG. 3. [Diagram 5] 3 is a cross-sectional view taken along line AA' of FIG. 2, illustrating a situation in which thermal runaway occurs in the battery pack according to the present embodiment. [Figure 6]This is a cross-sectional view along the line A-A' of Figure 2, showing how the base melting portion melts in a battery pack according to this embodiment, and how the coolant fills up to the battery cell accommodating space through the melted portion of the base melting portion, thereby immersing the battery cell in the coolant. [Figure 7] 3 is a view seen from the direction B in FIG. 2 with the battery cell removed. [Figure 8] This is a view seen from direction B in FIG. 2. [Figure 9] 5 is an enlarged view of a portion D in FIG. 4 showing a battery pack according to another embodiment of the present invention. [Figure 10] 4 is a flowchart of a method for extinguishing a fire in a battery pack according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] The present invention can be modified in various ways and can have various embodiments, and a specific embodiment will be illustrated in the drawings and described in detail in the description of the invention. However, this is not intended to limit the present invention to the specific embodiment, and it should be understood that the present invention includes all modifications, equivalents, and alternatives that fall within the spirit and technical scope of the present invention. In describing the present invention, the same identification symbols are used for the same components even if other embodiments are shown.

[0022] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. The same or corresponding elements are designated by the same reference numerals, and redundant description thereof will be omitted.

[0023] In the following examples, the terms "first", "second" and the like are not used in a limiting sense but are used for the purpose of distinguishing one component from another component.

[0024] In the following examples, singular expressions include plural expressions unless the context clearly indicates otherwise.

[0025] In the following examples, terms such as "comprise" or "have" mean the presence of a feature or component described in the specification, and do not preclude the possibility of adding one or more other features or components.

[0026] In the drawings, the size of components may be exaggerated or reduced for convenience of explanation. For example, the size and thickness of each component shown in the drawings are arbitrarily shown for convenience of explanation, and the present invention is not necessarily limited to what is shown in the drawings.

[0027] If an embodiment can be implemented differently, the order of certain steps may be performed differently than that described. For example, two steps described as successive may be performed substantially simultaneously or may be performed in the reverse order from that described.

[0028] The terms used in this application are merely used to describe certain embodiments and are not intended to limit the present invention. In this application, the terms "comprise" or "have" are intended to specify the presence of a feature, number, step, operation, component, part, or combination thereof described in the specification, and should be understood not to preclude the presence or additional possibility of one or more other features, numbers, steps, operations, components, parts, or combinations thereof.

[0029] Hereinafter, a battery pack according to an embodiment of the present invention will be described with reference to FIGS.

[0030] Fig. 2 is a perspective view showing a battery pack according to an embodiment of the present invention. Fig. 3 is a cross-sectional view taken along line A-A' in Fig. 2, showing a state of a battery pack before thermal runaway according to an embodiment of the present invention. Fig. 4 is an enlarged view of part C in Fig. 3.

[0031] 2 to 4, a battery pack according to one embodiment of the present invention includes a battery housing 120 accommodating a plurality of battery cells, a battery cell accommodating space S2 in which the plurality of battery cells are accommodated within the battery housing, a lower space S1 disposed below the battery cell accommodating space S2 in the battery housing, and a battery cell base 130 formed between the lower space S1 and the battery cell accommodating space S2 and supporting the plurality of battery cells, and the battery cell base includes a base melting portion 132 that melts when heat of a predetermined temperature or more is generated in the battery cell, and a base non-melting portion 131 that does not melt when heat of a predetermined temperature or more is generated in the battery cell.

[0032] A plurality of battery cells 110 may be housed inside the battery housing 120. According to this embodiment, the battery cells are rectangular battery cells, but the type of the battery cells is not limited thereto, and may be cylindrical battery cells or pouch-type battery cells.

[0033] According to this embodiment, the battery housing 120 may include a battery cell accommodating space S2 in which the battery cells are accommodated and a lower space S1 in which the coolant is accommodated. The lower space S1 is disposed below the battery cell accommodating space S2 and accommodates the coolant w. The coolant accommodated in the lower space S1 may function to adjust the temperature of the battery pack by cooling heat generated during charging and discharging of the battery pack.

[0034] The cooling water w can be circulated in such a manner that it is supplied to the lower space S1 through the inlet 121 and discharged to the outside through the outlet 122.

[0035] The battery cell base portion 130 may be disposed in a plate shape between the lower space portion S1 and the battery cell accommodating space portion S2 to define the lower space portion S1 and the battery cell accommodating space portion S2. The battery cell base portion 130 may support a plurality of battery cells disposed in the battery cell accommodating space portion S2. In this case, a portion of the battery cell base portion 130 may be disposed to contact lower ends of the plurality of battery cells.

[0036] According to the present embodiment, the battery cell base part 130 may include a base non-meltable part 131 and a base meltable part 132. The base non-meltable part 131 does not melt when heat of a preset temperature or more is generated in the battery cell, while the base meltable part 132 melts when heat of a preset temperature or more is generated in the battery cell. That is, the base meltable part 132 and the base non-meltable part 131 may be made of different materials.

[0037] In this case, the base non-melting portion 131 can be made of a material having higher heat resistance than the base melting portion 132. The base non-melting portion 131 is also made of a material having such high heat resistance that it can withstand high temperatures and retains its shape without being deformed even when thermal runaway occurs in the battery cell.

[0038] The material of the base melting portion 132 is also a material having a lower melting point than the preset temperature, and the material of the base non-melting portion 131 is also a material having a higher melting point than the preset temperature.

[0039] If the internal temperature of a battery cell rises under certain conditions, an abnormal reaction may occur in the battery cell. In this case, as an example of an abnormal operating condition, a battery cell may be severely heated or an overcharged cell may cause thermal runway in the battery cell. If a fire occurs due to thermal runaway inside the battery pack, a fire extinguishing system that can extinguish the fire is required.

[0040] According to this embodiment, when thermal runaway of the battery cell occurs as shown in FIG. 5, the temperature around the battery cell increases due to the thermal runaway of the battery cell, and the base melting part 132 may melt due to the influence of the temperature as shown in FIG. 6. When the base melting part 132 melts, the cooling water w in the lower space part S1 is supplied, and the supplied cooling water w may flow into the battery cell accommodating space part S2 through a part of the base melting part 132 located before melting. The cooling water w' flowing into the battery cell accommodating space part S2 may be gradually filled by the supply of cooling water, and the battery cell 110 where thermal runaway has occurred may be immersed in the cooling water w'. By immersing the battery cell in the cooling water, the thermal runaway occurring in the battery cell 110 can be controlled and the fire inside the battery pack can be extinguished.

[0041] As described above, the battery pack according to the embodiment of the present invention may include a configuration in which the water cooling system and the fire extinguishing system are integrated into one system. That is, the base melting part 132 at the lower end of the battery cell is formed to melt by high temperature heat when the battery cell thermal runaway occurs, and the lower space part S1 and the battery cell receiving space part S2 may be connected to each other as the base melting part 132 melts. At this time, the cooling water w in the lower space part S1 is filled up to the battery cell receiving space part S2 where the battery cell 110 is located, and the battery cell is immersed, thereby performing the fire extinguishing function of the battery pack.

[0042] As a result, in a normal state, the temperature of the entire battery pack is controlled using a water-cooling system via the lower space S1 of the battery pack and the cooling water w filled in the lower space, and in an emergency state such as when a thermal runaway occurs in a battery cell, the cooling water of the water-cooling system is naturally introduced into the battery cell due to high heat without a separate power source, immersing the battery cell, and the water-cooling system can be used to perform a fire extinguishing function in an emergency.

[0043] This allows the internal structure of the battery pack to be made compact, and the number of parts placed inside the battery pack can be reduced, thereby reducing the volume and weight occupied by the parts, thereby providing the effect of generally improving the energy density of the battery pack.

[0044] Hereinafter, a method for extinguishing a fire in a battery pack according to an embodiment of the present invention will be described with reference to FIGS.

[0045] Fig. 3 is a cross-sectional view taken along line A-A' in Fig. 2, showing a state of a battery pack before thermal runaway according to an embodiment of the present invention. Fig. 5 is a cross-sectional view taken along line A-A' in Fig. 2, showing a state in which thermal runaway occurs in a battery pack according to the present embodiment. Fig. 6 is a cross-sectional view taken along line A-A' in Fig. 2, showing a state in which a base melting portion melts in a battery pack according to the present embodiment, and coolant fills up to a battery cell receiving space through the melted portion of the base melting portion, so that the battery cells are immersed in the coolant. Fig. 10 is a flowchart of a method for extinguishing a fire in a battery pack according to an embodiment of the present invention.

[0046] A method for extinguishing a fire in a battery pack according to one embodiment of the present invention includes a step (S100) of generating thermal runaway F in a battery cell 110 as shown in FIG. 5, a step (S200) of melting a base melting portion 132 adjacent to the battery cell 110 as shown in FIG. 6, and a step (S300) of immersing the battery cell 110 in the cooling water w while the cooling water w in the lower space portion S1 flows into the battery cell accommodating space portion S2 through the portion where the base melting portion 132 is located.

[0047] Hereinafter, a structure of a battery cell base part of a battery pack according to an embodiment of the present invention will be described in more detail with reference to FIGS.

[0048] Fig. 4 is an enlarged view of part C in Fig. 3. Fig. 7 is a view from the direction B in Fig. 2 with the battery cell removed. Fig. 8 is a view of the battery pack from the direction B in Fig. 2.

[0049] 4, 7 and 8, the battery cell base part 130 according to an embodiment of the present invention may include a base non-meltable part 131 and a base meltable part 132. In this case, the base non-meltable part 131 may include a first base non-meltable part 131a in contact with a lower end part of the battery cell 110 and a second base non-meltable part 131b spaced apart from the battery cell 110. In this case, the base meltable part 132 may be disposed between the first base non-meltable part 131a and the second base non-meltable part 131b.

[0050] The first base non-meltable portion 131a may be formed in a shape corresponding to a lower end of the battery cell 110 to support the battery cell 110, and may be disposed at a position in contact with the lower end of the battery cell 110. For example, the first base non-meltable portion 131a may be connected to a support pillar E to enable the battery cell 110 to be safely supported on the battery cell accommodating space portion S2.

[0051] In this case, the end of the first base unmeltable portion 131a may be formed at the end point of the rounded corner portion R at the lower end of the battery cell. As a result, when thermal runaway occurs in the battery cell, the cooling water w in the lower space S1 may rapidly flow into the battery cell accommodating space S2 along the rounded corner portion R at the lower end of the battery cell.

[0052] The second base unmeltable portion 131b may be disposed in a portion that does not contact the lower end portion of the battery cell 110. In a normal state in which thermal runaway does not occur, the second base unmeltable portion 131b, together with the base melting portion 132, defines the lower space portion S1 and the battery cell accommodating space portion S2, and may prevent the cooling water w in the lower space portion S1 from penetrating into the battery cell accommodating space portion S2.

[0053] 7, the base fusion part 132 may be disposed between the first base unmeltable part 131a and the second base unmeltable part 131b. The base fusion part 132 may be formed along the periphery of the first base unmeltable part 131a formed in a shape corresponding to the lower end of the battery cell 110. That is, the base fusion part 132 may be formed along the periphery of the adjacent battery cell 110, which may be the starting point of thermal runaway detection and may allow the coolant to first enter the outer surface part of the battery cell 110, which is relatively hotter than other spaces.

[0054] 7 and 8, the base melting portion 132 may include a melting portion first width w1, which is a width at a portion corresponding to a narrow width portion t1 of the battery cell placed on the base non-melting portion 131, and a melting portion second width w2, which is a width at a portion corresponding to a wide width portion t2 of the battery cell placed on the base non-melting portion 131. In this case, the first melting portion width w1 and the second melting portion width w2 may be variable.

[0055] That is, there may be a side where thermal runaway occurs more strongly between the short width part t1 and the long width part t2 depending on the specifications of the battery cell 110. Therefore, it is possible to analyze in advance which side is more likely to cause thermal runaway depending on the internal structure of the battery cell 110, and to make the melting part width on the side where thermal runaway is more likely to occur relatively larger. As a result, when thermal runaway occurs in the battery cell, the cooling water can be filled more quickly in the part of the short width part or the long width part where thermal runaway occurs more strongly, thereby making it possible to carry out fire suppression more quickly.

[0056] Hereinafter, a battery pack according to another embodiment of the present invention will be described with reference to FIG.

[0057] FIG. 9 is an enlarged view of a portion D in FIG. 4, illustrating a battery pack according to another embodiment of the present invention.

[0058] 9, in the base fusion portion 132 according to the present embodiment, the height h1 of the portion adjacent to the first base non-melted portion 131a is lower than the height h2 of the portion adjacent to the second base non-melted portion 131b.

[0059] In other words, the height of the base melting portion 132 becomes lower as it approaches the portion of the base melting portion 132 that is relatively closer to the battery cell 110. This allows the portion of the base melting portion 132 adjacent to the battery cell 110 to melt first when thermal runaway occurs in the battery cell 110, and allows the cooling water w to flow into the portion close to the battery cell 110 first.

[0060] The present invention has been described based on the embodiment shown in the drawings, but this is merely an example. Those skilled in the art will fully understand that various modifications and equivalent embodiments are possible from the embodiment. Therefore, the true technical scope of the present invention should be determined based on the claims.

[0061] The specific technical contents described in the embodiments are merely examples and do not limit the technical scope of the embodiments. In order to provide a concise and clear description of the invention, descriptions of conventional general techniques and configurations may be omitted.

[0062] In addition, the line connections or connecting members between components shown in the drawings are illustrative of functional connections and / or physical or circuit connections, and may be replaced or expressed by various other functional connections, physical connections, or circuit connections in an actual device. Furthermore, unless specifically stated as "essential" or "important," a component may not necessarily be required to apply the present invention.

[0063] In the description of the invention and claims, "the" or similar indicators refer to both the singular and the plural unless otherwise specified. Furthermore, when a range is described in the examples, it includes inventions to which individual values ​​within the range are applied (unless otherwise specified), as if each individual value constituting the range was described in the description of the invention.

[0064] Additionally, unless steps constituting a method according to an embodiment are expressly described in an order or described to the contrary, the steps may be performed in any suitable order.

[0065] The examples are not necessarily limited by the order of description of the steps. The use of any examples or exemplary terms (e.g., "etc.", etc.) in the examples is merely to describe the examples in detail, and the scope of the examples is not limited by the examples or exemplary terms, unless otherwise limited by the claims.

[0066] Moreover, those of ordinary skill in the art will recognize that various modifications, combinations, and variations can be made within the scope of the appended claims or equivalents thereof depending on design conditions and factors. [Explanation of symbols]

[0067] 100 Battery Pack 110 Battery Cell 120 Battery Housing 121 Inlet 122 Outlet 130 Battery cell base S1 Lower space S2 Battery cell housing space 131 Base non-melted part 131a First base non-melted part 131b Second base non-melted part 132 Base fusion zone w1 First width of fusion zone w2 Second width of fusion zone h1 First height of fusion zone h2 Second fusion height t1 Short width of battery cell t2 Long width of battery cell E Support column F Thermal runaway W Lower space cooling water W' Cooling water filled in the battery cell storage space

Claims

1. a battery housing that houses a plurality of battery cells; a battery cell accommodating space portion in which the plurality of battery cells are accommodated within the battery housing; a lower space portion disposed below the battery cell accommodating space portion within the battery housing; a battery cell base portion formed between the lower space portion and the battery cell accommodating space portion and supporting the plurality of battery cells; The battery cell base portion includes: a base melting portion that melts when heat equal to or exceeds a preset temperature is generated in the battery cell; a base non-meltable portion that does not melt when heat equal to or exceeds a preset temperature is generated in the battery cell.

2. The base non-melted portion is a first base unmelted portion in contact with a lower end portion of the battery cell; a second base unfused portion spaced apart from the battery cell; The battery pack according to claim 1 , wherein the base molten portion is disposed between the first base unmelted portion and the second base unmelted portion.

3. The base fusion zone is The battery pack according to claim 2 , wherein a height of the portion adjacent to the first base unmelted portion is lower than a height of the portion adjacent to the second base unmelted portion.

4. The battery pack according to claim 2 , wherein an end of the first base unmeltable portion is formed at a termination point of a rounded corner portion of a lower end portion of the battery cell.

5. The base fusion zone is a first fusion portion width, which is a width at a portion corresponding to a short width portion of the battery cell placed on the base non-fusion portion; a second fused portion width, which is a width at a portion corresponding to a long width portion of the battery cell placed on the base non-fused portion; The battery pack of claim 1 , wherein the first fusion zone width and the second fusion zone width are variable.

6. a stage where thermal runaway of the battery cell occurs; Melting a base melting portion adjacent to the battery cell; and flowing the cooling water in the lower space into the battery cell accommodating space through a portion where the base fusion portion is located, and immersing the battery cells in the cooling water.

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