KR20240042714A - Battery pack having a structure capable of venting gas while preventing flame emission - Google Patents

Abstract

A battery module including one or more battery cell stacks including a plurality of secondary battery cells and a module frame for housing the battery cell stacks; A case storing one or more battery modules; and a flame retardant member, wherein the flame retardant member includes: a first mesh-type sheet; and a flame retardant sheet or a second mesh-type sheet including one or more holes. A battery pack including a is disclosed.

Description

Battery pack having a structure that prevents flame emission and discharges gas {BATTERY PACK HAVING A STRUCTURE CAPABLE OF VENTING GAS WHILE PREVENTING FLAME EMISSION}

This relates to a battery pack including a plurality of battery modules, and in particular, relates to a battery pack having a structure capable of discharging gas while preventing flame emission.

Secondary batteries can be charged and discharged multiple times, so they are applied to various fields such as digital cameras, mobile phones, and laptops. Nickel-cadmium batteries, nickel-metal hydride batteries, nickel-hydrogen batteries, and lithium secondary batteries are commonly used secondary batteries. With the development of portable electronic devices, much research has been conducted on lithium secondary batteries with high energy density and discharge voltage and little memory effect.

In particular, in addition to small devices, secondary batteries have begun to be widely used in medium to large-sized devices such as electric vehicles (EV) and energy storage systems (ESS). Unlike small devices that use a small amount of secondary battery cells, mid- to large-sized devices use battery modules or battery packs that electrically connect a large number of secondary battery cells to increase capacity and output. Pouched type secondary battery cells have the advantage of being easy to stack and are actively used in medium to large-sized devices.

Secondary battery cells generally include a positive electrode containing lithium-based oxide, a negative electrode containing carbon material, a separator to prevent direct contact between them, and an electrolyte solution through which lithium ions can move. The separator may be damaged, resulting in a short circuit between the positive and negative electrodes, or the thermal runaway phenomenon of the secondary battery cell may occur in overcharge or overdischarge situations or under high temperature conditions. When thermal runaway occurs, the solid electrolyte interface (SEI) at the interface between the anode and cathode reacts to generate heat and gas, the anode material decomposes to generate heat and oxygen, and the electrolyte reacts to generate heat and combustible gas. . These reactions occur in a chain reaction, making it impossible to control the temperature rise of the secondary battery, and as a result, the secondary battery cell ignites or explodes.

If a thermal runaway phenomenon occurs in a battery module in which multiple secondary battery cells are connected in series/parallel, high-temperature gas or flame may spread to the surrounding area, resulting in serial ignition and explosion. In particular, in battery modules where secondary battery cells are housed inside the housing, there is a problem that increased pressure due to flame and gas generation can easily lead to explosion. This problem also applies to battery packs that include multiple battery modules.

Previous attempts have been made to improve this problem by changing the structure of the battery module and applying a gas outlet through which gas can pass. However, in a battery module with this structure, there is a problem in that gas and flame are discharged together through the gas outlet.

To solve this problem, methods have been attempted to extend the flow path of flame and gas by installing a type of blocking film to delay the spread of the flame or guide it in a certain direction. However, this structure has a problem in that gas is not discharged smoothly.

The description in this specification was created in consideration of the problems of the prior art described above, and is capable of smoothly discharging gas generated from internal secondary battery cells and at the same time suppressing the spread of flames caused by ignition of secondary battery cells. The purpose is to provide a battery pack equipped with a flame-blocking structure that can be used.

According to one aspect of the present specification for solving the above-mentioned problem, a battery module including one or more battery cell stacks including a plurality of secondary battery cells and a module frame for storing the battery cell stacks; A case storing one or more battery modules; and a flame retardant member, wherein the flame retardant member includes: a first mesh-type sheet; and a flame retardant sheet or a second mesh-type sheet including one or more holes. A battery pack including a is provided.

In one embodiment, the flame retardant member may include two or more flame retardant sheets, and the mesh-type sheet may be interposed between two or more flame retardant sheets.

In one embodiment, the flame retardant member includes the first and second mesh sheets, and the first and second mesh sheets may have different sieve opening sizes.

In one embodiment, the flame retardant member may include the flame retardant sheet and first and second mesh sheets, and the flame retardant sheet may be interposed between the first and second mesh sheets.

In one embodiment, the flame retardant sheet includes mica, and the mesh-type sheet may include one or more selected from the group consisting of aluminum, copper, iron, stainless steel, brass, and bronze.

According to one aspect of the present specification, gas generated from a secondary battery cell can be smoothly discharged to the outside.

According to another aspect, it is possible to prevent flames generated from secondary battery cells from spreading outside the battery pack.

The effect of one aspect of the present specification is not limited to the effects described above, and should be understood to include all effects that can be inferred from the configuration described in the detailed description or claims of the present specification.

1 is a perspective view schematically showing a battery pack according to an embodiment of the present specification.
Figure 2 is a perspective view schematically showing a battery module according to an embodiment of the present specification.
Figure 3 is a perspective view schematically showing a module frame that is part of a battery module according to an embodiment of the present specification.
Figure 4 is a plan view and a side cross-sectional view schematically showing a flame retardant member that is part of a battery module according to an embodiment of the present specification.
Figure 5 is a plan view and a side cross-sectional view schematically showing a flame retardant member that is part of a battery module according to another embodiment of the present specification.
Figure 6 is a plan view and a side cross-sectional view schematically showing a flame retardant member that is part of a battery module according to another embodiment of the present specification.
7 to 10 are side cross-sectional views schematically showing a battery module according to an embodiment of the present specification.

Hereinafter, one aspect of the present specification will be described with reference to the attached drawings. However, the description in this specification may be implemented in various different forms, and therefore is not limited to the embodiments described herein. In order to clearly explain one aspect of the specification in the drawings, parts that are not related to the description are omitted, and similar parts are given similar reference numerals throughout the specification.

Throughout the specification, when a part is said to be “connected” to another part, this includes not only cases where it is “directly connected,” but also cases where it is “indirectly connected” with another member in between. . Additionally, when a part is said to “include” a certain component, this does not mean that other components are excluded, but that other components can be added, unless specifically stated to the contrary.

When a range of numerical values is described herein, unless the specific range is stated otherwise, the value has the precision of significant figures given in accordance with the standard rules in chemistry for significant figures. For example, the number 10 includes the range 5.0 to 14.9, and the number 10.0 includes the range 9.50 to 10.49.

In this specification, “thermal runaway” refers to a phenomenon in which a chain reaction of exothermic reactions occurs due to electrochemical side reactions of materials inside the battery. It is known that a battery in which thermal runaway occurs reaches a high temperature of over 400°C within a few seconds, spews out gas, and is virtually impossible to extinguish before it burns out.

Hereinafter, the battery pack 1 according to one aspect of the present specification will be described in detail with reference to the attached drawings.

Battery pack (1)

The battery pack 1 according to one aspect of the present specification includes one or more battery cell stacks 100 including a plurality of secondary battery cells and a module frame 200 for housing the battery cell stacks 100. a battery module (10); A case (20) storing one or more battery modules (10); and a flame retardant member 300, wherein the flame retardant member 300 includes a first mesh-type sheet 321; and a flame retardant sheet 310 or a second mesh-type sheet 322 including one or more holes.

Figure 1 schematically shows a battery pack 1 according to an embodiment of the present specification. In Figure 1, the battery pack 1 is shown with the top portion of the case 20 omitted to confirm the internal structure. The description of the battery pack 1 in this specification is not limited by these drawings.

Referring to FIG. 1, a battery pack 1 according to an aspect of the present specification may include one or more battery modules 10. Here, the battery pack 1 may include one or more battery modules 10 accommodated in the case 20 . Figure 1 illustrates the shape of the case 20 as a simplified rectangular parallelepiped structure, but it is not limited thereto.

Each battery module 10 may be electrically interconnected in series and/or parallel. This electrical connection can be made through a conductive material (not shown). The conductive material may be, for example, an electric wire, a conductive bar, etc. As an example, the conductive material may be a bus bar electrically connected to the electrode terminal of one or more secondary battery cells, but is not limited thereto.

According to one aspect, one or more battery modules 10 may be stored in the case 20. Case 20 may be formed as one piece, or may be formed by combining two or more components. For example, the case 20 may be a combination of a lower case and an upper case, or a lower case and an upper case may be combined through a side case that supports the battery module 10, but the case is not limited thereto.

If the case 20 is a combination of two or more, they may be joined by methods such as welding or physical fastening. The case 20 is made of metal such as steel or aluminum or polymer resin with sufficient strength to prevent external shock from being applied directly to the battery module 10 or the secondary battery cell. Depending on the usage environment of the battery pack 1, the material on each side of the case 20 may be the same or different.

The case 20 may have a coupling structure (not shown) to which each battery module 10 can be fixedly installed. Case 20, for example, has at least one of a coupling structure coupled to the lower surface of the battery module 10, coupled to the side surface of the battery module 10, or coupled to the upper surface of the battery module 10. It may include, but is not limited to this.

In one embodiment, the case 20 may include a gas outlet (not shown) capable of discharging internal gas to the outside. If the case 20 of the battery pack 1 includes a gas discharge portion, the flame retardant member 300 may be positioned to correspond to at least a portion of the gas discharge portion, but is not limited to this.

In an example of the case 20 including one or more battery modules 10, one battery module 10 may be isolated from at least one other battery module 10 by a partition, but the present invention is not limited thereto. When the case 20 includes a partition wall, at least a portion of the partition wall may be the flame retardant member 300, but is not limited thereto.

The battery pack 1 may further include a control module 30 capable of controlling one or more battery modules 10 as needed. The control module 30 may include a Battery Control Unit (BCU), a Battery Management System (BMS), a Battery Disconnect Unit (BDU), etc. The control module 30 controls power, etc. according to the state of the secondary battery cell or battery module 10 inside the battery pack 1 to prevent safety accidents, or controls the charging and discharging state of the battery pack 1 to control the battery. Lifespan can be extended effectively. The control module 30 may include a sensor to check the current, voltage, temperature, etc. of the battery pack 1 in real time.

If the secondary battery cells inside the battery module 10 are exposed to external shock, safety accidents such as ignition or explosion may occur. Therefore, the case 20 may further include a buffer member to protect the battery module 10 from external shock.

The battery pack 1 according to one aspect may include a flame retardant member 300. Here, the flame retardant member 300 may be provided in the battery module 10 or in the case 20. The flame retardant member 300 includes a mesh-type sheet 320 and can allow gas to pass while suppressing the spread of flame.

Battery module(10)

A battery module 10 according to one aspect includes one or more battery cell stacks 100 including a plurality of secondary battery cells; A module frame 200 that accommodates the battery cell stack 100; and a flame retardant member 300, wherein the flame retardant member 300 may include at least one selected from the group consisting of a flame retardant sheet 310 and a mesh-type sheet 320 including one or more holes.

Figure 2 schematically shows a battery module 10 according to an embodiment of the present specification. Referring to FIG. 2, the battery module 10 according to one embodiment may have one or more battery cell stacks 100 accommodated inside the module frame 200. In addition, Figure 2 shows the end plate 230 coupled to the front and rear openings of the module frame 200, but the openings are not closed, but the present invention is not limited thereto.

The battery module 10 houses cells, which are the basic units of secondary batteries, connected in series or parallel. In electric vehicles and power storage systems that require larger capacity and higher voltage, multiple battery modules 10 can be connected to form a battery pack 1.

The battery module 10 is not simply a combination of a plurality of secondary battery cells, but is stored inside a rigid module frame 200 to protect the secondary battery cells from external shocks such as heat and vibration. In addition, it may further include electronic devices and a cooling device for a battery management system (BMS) to safely and efficiently manage a large number of secondary battery cells.

That is, the battery module 10 is used as a unit structure in fields that require medium to large batteries.

Battery cell stack (100)

The battery cell stack 100 is formed by stacking a plurality of secondary battery cells. In Figure 2, the secondary battery cells are arranged perpendicular to the floor and are shown as stacked in the left and right directions, but if necessary, they may be stacked in a front-to-back direction perpendicular to the floor or in a vertical direction horizontal to the floor.

Each secondary battery cell may be a pouch-type secondary battery in which electrode leads protrude outside the pouch. A pouch-type secondary battery may have an electrode assembly including an electrode plate, an electrode tab, and a separator stored in a pouch. After this electrode assembly is stored in the pouch, electrolyte can be injected and the secondary battery cell can be activated. In an activated secondary battery cell, a solid electrolyte layer can be created on the anode and cathode. In another example, the secondary battery cell may be a prismatic secondary battery or a cylindrical secondary battery in which the electrode assembly is stored in a can. In another example, the secondary battery cell may be a solid battery cell including an electrode plate, an electrode tab, and a solid electrolyte, but is not limited thereto.

The pouch is an exterior material that forms the outer shape of a secondary battery cell, and may have a receiving portion formed inside to store an electrode assembly. The pouch can contain an external insulating layer, a metal layer, an internal adhesive layer, etc., and can be sealed after storing the electrode assembly. The electrode assembly inside the sealed pouch can be electrically connected to the outside only with electrode leads. The electrode assembly stored in the pouch may be in the form of a pressurized jelly roll wound so that the anode and cathode are separated by a separator, or may be in a stacking form in which the anode and cathode are alternately stacked around the separator.

A can is an exterior material that forms the outer shape of a secondary battery cell. Depending on its shape, it is classified into a flat rectangular rectangular secondary battery and a cylindrical secondary battery. The electrode assembly stored in the can of the square secondary battery may be the same as that of the pouch described above. The electrode assembly stored in a cylindrical secondary battery can may be in the form of a jelly roll wound so that a separator separates the positive and negative electrodes.

The electrode plate includes a positive electrode plate and a negative electrode plate, and one or more positive electrode plates and one or more negative electrode plates may be disposed with a separator interposed therebetween. Each electrode plate is provided with an electrode tab, and one or more electrode tabs may be connected to an electrode lead. For example, one or more positive plates may each be connected to a positive electrode tab, and one or more positive electrode tabs may be connected to a positive lead. Similarly, one or more negative electrode plates may each be connected to a negative electrode tab, and one or more negative electrode tabs may be connected to a positive electrode lead. Here, the anode lead and the cathode lead may be arranged at different heights or in different directions so as not to contact each other.

The electrode plate may be formed by applying an active material slurry to a current collector. The current collector generally uses copper foil at the negative electrode and aluminum foil at the positive electrode, but is not limited to this. The active material slurry may be applied by mixing active materials such as positive electrode materials or negative electrode materials, conductive materials, binders, additives, etc. in a solvent.

The positive electrode active material can decompose at high temperatures and generate oxygen. The generated oxygen can oxidize the electrolyte or react with the positive electrode active material to generate heat.

The separator is a porous film made from polymer materials that allows ions to pass through while blocking direct contact between the positive and negative plates. If the separator is damaged by external impact or dendrites grown inside, a short circuit may occur where the anode and cathode come into contact, which may cause thermal runaway of the secondary battery cell. At abnormally high temperatures caused by thermal runaway, secondary battery cells may ignite or explode.

The battery module 10 may include one or more battery cell stacks 100. If one secondary battery cell ignites, the flame can transfer to adjacent cells, causing a chain thermal runaway phenomenon. Therefore, when two or more battery cell stacks 100 are included, each battery cell stack 100 may be distributed and isolated from each other. Additionally, in each battery cell stack 100, secondary battery cells are isolated from each other, thereby suppressing or slowing down chain thermal runaway.

The number of secondary battery cells included in one battery cell stack 100 may be set in consideration of capacity per unit volume of the battery module 10, stability, use environment, etc. For example, two, three, four, five, six, seven, eight, nine, or ten secondary battery cells may be stacked to form one battery cell stack 100, but the present invention is not limited thereto.

The electrode lead of each secondary battery cell may be electrically connected by aligning the electrode lead with the electrode lead of the adjacent secondary battery cell. If two or more battery cell stacks 100 are included, each battery cell stack 100 may be electrically connected.

Module frame (200)

One or more battery cell stacks 100 may be accommodated in the module frame 200 that forms the skeleton of the battery module 10. At this time, the bus bar for electrical connection between each battery cell stack 100, the fixing member for fixing the battery cell stack 100, the buffer member for alleviating external shock, and the management of the battery module 10. Additional printed circuit boards and various sensors can be accommodated.

FIG. 2 schematically shows a module frame 200 that is part of the battery module 10 according to an embodiment of the present specification. Referring to FIGS. 2 and 3 , the module frame 200 according to one embodiment may be provided with a space therein for storing the battery cell stack 100 and the like.

The module frame 200 may be in the form of a square pillar having an upper and lower surface and side parts connecting it, but is not limited thereto. The module frame 200 may have one or more openings to accommodate the battery cell stack 100.

Figure 2 shows a module frame 200 provided with openings on both the front and back sides. This type of module frame 200 having four sides has the entire surface formed integrally, each side is joined through welding, physical fastening, etc., the upper or lower surface is coupled to a U-shaped frame, or the upper and lower surfaces are formed as one body. It can be formed in various ways, such as by combining a frame in which the lower part is connected to one side part.

The end plate 230 may be coupled to the opening of the module frame 200 by welding, physical fastening, etc. The end plate 230 may close the opening of the module frame 200 after the components of the battery module 10 are accommodated. The battery cell stack 100 may be electrically connected to the outside through the end plate 230, but is not limited to this.

The module frame 200 to the end plate 230 is made of metal such as steel or aluminum or polymer resin with sufficient strength to prevent external shock from being directly applied to the secondary battery cell. Depending on the usage environment of the battery module 10, the materials of each side of the module frame 200 and the end plate 230 may be the same or different.

When a secondary battery cell is exposed to high temperatures, the internal solid electrolyte layer, positive electrode material, negative electrode material, and electrolyte solution may react and generate oxygen, combustible gas, etc. They burn at high temperatures, causing fire and explosion. Therefore, there is a need to discharge gas in order to suppress chain thermal runaway or prevent explosion in the battery module 10. The module frame 200 may be provided with one or more gas outlets 210 to discharge internal gas, if necessary.

Figure 3 shows a module frame 200 having a rectangular gas outlet 210 on the upper surface, but the battery module 10 of the present specification is not limited thereto. For example, a gas outlet 210 may be provided on the side of the module frame 200, or a separate gas outlet 210 may not be provided on the module frame 200. Alternatively, the shape, size, and number of the gas outlet 210 may be different from those in the drawing.

The location and shape of the gas outlet 210 may vary depending on the characteristics of the battery cell stack 100, the operating purpose and environment of the battery pack 1, and the storage type of the battery module 10. If the module frame 200 does not have a gas outlet 210, the end plate 230 may be provided with a gas outlet. In this case, a separate function can be given by adjusting the material or shape of the end plate 230. In one example, the gas outlet 210 may have a long shape in the longitudinal direction of the internal secondary battery cell.

One or more coupling holes 220 are formed on the lower surface of the module frame 200 of FIG. 3. These coupling holes 220 can be used to couple and secure the module frame 200 to the outside or to couple a specific member inside the module frame 200. For example, it can be coupled and fixed to the case 20 of the battery pack 1 through the coupling hole 220.

Flame retardant member (300)

When a secondary battery cell ignites, the flame can spread to the surrounding area, causing a chain thermal runaway. Additionally, flame may spread outside the battery module 10, causing a secondary fire. High-temperature gas generated during thermal runaway of a secondary battery cell contains combustible substances and causes flames to spread. Additionally, when gas accumulates inside the case 20 or the module frame 200, the pressure increases, resulting in an explosion. Therefore, there is a need to discharge the gas generated by thermal runaway but prevent the spread of flame. The flame retardant member 300 can prevent the spread of flame while discharging high-temperature gas inside the case 20 or module frame 200.

The flame retardant member 300 according to one aspect may include at least one selected from the group consisting of a flame retardant sheet 310 and a mesh-type sheet 320 including one or more holes.

The flame retardant sheet 310 is a plate-shaped structure and may include one or more holes to allow gas to pass through. At this time, the shape and size of the hole are not limited, but if it is smaller than the diameter of the gas outlet 210 described above, it can be easily manufactured and the possibility of external foreign substances entering may be low. Each hole in the flame retardant sheet 310 may be the same or different in size. For example, the hole size near the center of the flame retardant sheet 310 may be larger, the same, or smaller than the hole size near the outside. Additionally, if the flame retardant member 300 includes two or more flame retardant sheets 310, the hole sizes of the different flame retardant sheets 310 may be the same or different. For example, depending on the purpose, the hole size of the flame retardant sheet 310 located on the outside may be larger, the same, or smaller than that of the flame retardant sheet 310 located on the inside.

As another example, at least one of the flame retardant sheets has a diameter of each hole of 3 to 20 mm, that is, 3 mm, 3.5 mm, 4 mm, 4.5 mm, 5 mm, 5.5 mm, 6 mm, 6.5 mm, 7 mm, 7.5 mm, 8 mm, 8.5 mm, 9 mm, 9.5 mm, 10 mm, 10.5 mm, 11 mm, 11.5 mm, 12 mm, 12.5 mm, 13 mm, 13.5 mm, 14 mm, 14.5 mm, 15 mm, 15.5 mm , 16 mm, 16.5 mm, 17 mm, 17.5 mm, 18 mm, 18.5 mm, 19 mm, 19.5 mm, 20 mm, or a range between any two of these values. If the hole sizes of the flame retardant sheet 310 are all outside the above range, gas discharge may not be smooth or it may be difficult to block the flame.

The flame retardant sheet 310 may be made of a material having flame retardant or non-combustible performance. Flame retardant performance refers to the characteristics of a material that is difficult to burn, and can be measured using the UL94 test method. In general, V-0, V-1, and V-2 grade materials according to the UL94 test method are recognized as flame retardant materials. For example, the flame retardant sheet 310 may be a mica sheet, but it is not limited to this and can be used as long as it has equivalent or superior performance.

As long as the flame retardant or non-flammable performance described above is satisfied, the flame retardant sheet 310 may be one having excellent mechanical strength such as tensile strength, impact strength, and flexural strength. If the flame retardant sheet 310 has excellent mechanical strength, it maintains its shape and blocks flames in situations where external shock is applied or pressure is applied from the inside due to swelling of secondary battery cells, etc., and at the same time discharges internal gas. can do.

Additionally, heat transfer to the outside can be minimized by using a flame retardant sheet 310 with low thermal conductivity. If the flame retardant sheet 310 has low thermal conductivity, it can perform a role similar to a kind of heat-resistant layer.

The flame retardant sheet 310 may have insulating properties. If the flame retardant sheet 310 has insulation properties expressed in terms of insulation breakdown voltage, insulation resistance, etc., abnormal current in the secondary battery cell generated due to a short circuit, etc. can be prevented from being transmitted to the outside.

The thickness of the flame retardant sheet 310 is 0.1 to 1.5 mm, for example, 0.1 mm, 0.15 mm, 0.2 mm, 0.25 mm, 0.3 mm, 0.35 mm, 0.4 mm, 0.45 mm, 0.5 mm, 0.55 mm, 0.6 mm, 0.65 mm, 0.7 mm, 0.75 mm, 0.8 mm, 0.85 mm, 0.9 mm, 0.95 mm, 1.0 mm, 1.05 mm, 1.1 mm, 1.15 mm, 1.2 mm, 1.25 mm, 1.3 mm, 1.35 mm, 1.4 mm, 1.45 mm , 1.5 mm or a thickness in the range between these two values, but is not limited thereto. The thickness of the flame retardant sheet 310 can be selected as thin as is appropriate for the usage environment. For example, in the flame retardant member 300 including two or more flame retardant sheets 310, the flame retardant sheet 310 close to the outside has a high possibility of being subjected to a direct impact, so a thicker sheet may be used.

The mesh-type sheet 320 can block the spread of flame while discharging gas. The mesh-type sheet 320 may be manufactured from a material with excellent thermal conductivity. In one example, the mesh sheet 320 may include one or more selected from the group consisting of aluminum, copper, iron, stainless steel, brass, and bronze. When the flame passes through the mesh sheet 320, the heat energy required for the combustion reaction is transferred to the mesh sheet 320, thereby suppressing the spread of the flame.

The thickness of the mesh sheet 320 is 0.1 to 5 mm, for example, 0.1 mm, 0.12 mm, 0.14 mm, 0.16 mm, 0.18 mm, 0.2 mm, 0.22 mm, 0.24 mm, 0.26 mm, 0.28 mm, 0.3 mm. , 0.32 mm, 0.34 mm, 0.36 mm, 0.38 mm, 0.4 mm, 0.42 mm, 0.44 mm, 0.46 mm, 0.48 mm, 0.5 mm, 0.52 mm, 0.54 mm, 0.56 mm, 0.58 mm, 0.6 mm, 0.62 mm, 0.64 mm, 0.66 mm, 0.68 mm, 0.7 mm, 0.72 mm, 0.74 mm, 0.76 mm, 0.78 mm, 0.8 mm, 0.82 mm, 0.84 mm, 0.86 mm, 0.88 mm, 0.9 mm, 0.92 mm, 0.94 mm, 0.96 mm, 0.98 mm, 1 mm, 1.05 mm, 1.1 mm, 1.15 mm, 1.2 mm, 1.25 mm, 1.3 mm, 1.35 mm, 1.4 mm, 1.45 mm, 1.5 mm, 2 mm, 2.5 mm, 3 mm, 3.5 mm, 4 mm , 4.5 mm, 5 mm, or a range between these two values. If the thickness of the mesh sheet 320 is outside the above-mentioned range, the flame blocking effect may be insufficient or the space for providing other components may be insufficient.

The mesh sheet 320 has a mesh size of 40 to 1,000 mesh, for example, 40 mesh, 45 mesh, 50 mesh, 60 mesh, 70 mesh, 80 mesh, 100 mesh, 120 mesh, 140 mesh, 170 mesh, 200 mesh. The net may have a mesh size of 230 mesh, 270 mesh, 325 mesh, 400 mesh, 500 mesh, 600 mesh, 800 mesh, 1000 mesh, or a range between these two values, but is not limited thereto. If the mesh size of the mesh sheet 320 is too small, the discharge of gas may be slowed or blocked by contaminants. Conversely, if the mesh size of the mesh sheet 320 is too large, the flame may not be blocked.

The thickness of the mesh constituting the mesh sheet 320 is 0.05 to 1 mm, for example, 0.05 mm, 0.075 mm, 0.1 mm, 0.125 mm, 0.15 mm, 0.175 mm, 0.2 mm, 0.225 mm, 0.25 mm, 0.275 mm. mm, 0.3 mm, 0.325 mm, 0.35 mm, 0.375 mm, 0.4 mm, 0.425 mm, 0.45 mm, 0.475 mm, 0.5 mm, 0.525 mm, 0.55 mm, 0.575 mm, 0.6 mm, 0.625 mm, 0.65 mm, 0.675 mm, 0.7 mm, 0.725 mm, 0.75 mm, 0.775 mm, 0.8 mm, 0.825 mm, 0.85 mm, 0.875 mm, 0.9 mm, 0.925 mm, 0.95 mm, 0.975 mm, 1 mm or a range between two of these values can be satisfied. . A mesh-type sheet that satisfies the above-mentioned range can have sufficient mechanical strength and excellent flame blocking effect.

By removing the flame using the mesh sheet 320, the decrease in the gas discharge rate can be minimized. In addition, when two or more metal mesh sheets 320 are combined or used in combination with the flame retardant sheet 310, the mechanical strength of the flame retardant member 300 is excellent, making it possible to more easily protect the secondary battery cell from impacts applied from the inside and outside. . The flame retardant member 300, which has excellent mechanical strength, can function to block flames and discharge gas even in extreme environments. Additionally, if the mesh-type sheet 320 is used in combination with the flame retardant sheet 310, heat transfer can be minimized while blocking flames, or the transfer of abnormal current can be blocked if necessary.

In one example, the flame retardant member 300 includes two or more flame retardant sheets 310 each including one or more holes; and a mesh-type sheet 320 interposed between two or more flame retardant sheets 310; but is not limited thereto. Figure 4 schematically shows a flame retardant member 300, which is part of the battery pack 1 according to an embodiment of the present specification. Specifically, Figure 4 shows a flame retardant member 300 with a mesh-type sheet 320 interposed between the first flame retardant sheet 311 and the second flame retardant sheet 312 in a plan view at the top and a side cross-sectional view at the bottom. .

If the metal mesh sheet 320 is interposed between two or more flame retardant sheets 310, the secondary battery cell can be more easily protected from impacts applied from the inside and outside of the flame retardant member 300.

In one embodiment, the flame retardant member 300 including two or more flame retardant sheets 310 may be arranged so that a hole of one of the flame retardant sheets 310 does not overlap with a hole of one of the other flame retardant sheets 310. For example, referring to FIG. 4, all holes of the first flame retardant sheet 311 are arranged so as not to overlap with the holes of the second flame retardant sheet 312. If the holes of different flame retardant sheets 310 do not overlap each other, gas can be discharged to the outside while preventing foreign substances from passing through the flame retardant member 300. At this time, a predetermined space may exist between each flame retardant sheet 310 to allow gas to pass between the flame retardant sheets 310, or the flame retardant sheet 310 may have elasticity.

The plan view of FIG. 4 shows the flame retardant member 300 according to an example from the top. Referring to the plan view and side cross-sectional view of FIG. 4, the holes of the first flame retardant sheet 311 are arranged so as not to overlap the holes of the second flame retardant sheet 312. Therefore, in the top plan view, the mesh-type sheet 320 can be seen through the hole of the first flame retardant sheet 311, and the hole of the second flame retardant sheet 312 is not visible to the naked eye.

In another example, the flame retardant member 300 may include two or more mesh-type sheets 320, for example, a first mesh-type sheet 321 and a second mesh-type sheet 322, but is limited thereto. That is not the case. Figure 5 schematically shows a flame retardant member 300 that is part of the battery pack 1 according to another embodiment of the present specification. Specifically, Figure 5 shows the first mesh sheet 321 and the second mesh sheet 322 in a top plan view and a bottom side cross-sectional view.

In one embodiment, the first mesh sheet 321 and the second mesh sheet 322 may have different screen opening sizes. If two or more mesh sheets 320 with different sieve sizes are used, flame blocking performance can be excellent. Additionally, if two or more metal mesh sheets 320 are used, the secondary battery cell can be more easily protected from impacts applied from the inside and outside of the flame retardant member 300. For example, referring to FIG. 5 , an example in which the first mesh-type sheet 321 and the second mesh-type sheet 322 have different sieve sizes is shown. If the mesh-type sheets 320 have different sieve sizes, the amount of foreign substances passing through the flame retardant member 300 can be reduced, gas can be easily discharged to the outside, and the flame blocking effect can be excellent.

The plan view of FIG. 5 shows the flame retardant member 300 according to an example from the top. Referring to the top view and side cross-sectional view of FIG. 5, the screen size of the first mesh sheet 321 may be different from that of the second mesh sheet 322. Therefore, in the top plan view, the second mesh sheet 320 can be seen through the eyes of the first mesh sheet 321.

In another embodiment, a flame retardant sheet 310 may be interposed between two or more mesh-type sheets 320. For example, referring to FIG. 6, a flame retardant sheet 310 is interposed between the first mesh sheet 321 and the second mesh sheet 322. Here, the first mesh sheet 321 and the second mesh sheet 322 may be the same or different. The flame retardant member 300 in which the flame retardant sheet 310 is interposed between two or more mesh sheets 320 can have balanced improvements in heat resistance, mechanical strength, and flame blocking effect.

The plan view of FIG. 6 shows the flame retardant member 300 according to an example from the top. Referring to the plan view and side cross-sectional view of FIG. 6, the second mesh-type sheet 322 can be seen through the hole of the flame retardant sheet 310.

In one example of the battery module 10, a module frame 200 including one or more gas outlets 210 is used, and at least one of the holes in the flame retardant sheet 310 constituting the flame retardant member 300 is a gas outlet ( 210) and can be positioned to overlap. In particular, among several flame retardant sheets 310, it may be advantageous for gas discharge if one or more of the holes of the flame retardant sheet 310 located closest to the gas outlet 210 overlap.

For example, referring to FIG. 2, a gas outlet 210 is provided on the upper surface of the module frame 200. In the flame retardant member 300 located at the bottom of the module frame 200, at least one of the holes of the first flame retardant sheet 311 at the top overlaps the gas outlet 210. In this form, when gas and flame are generated in the internal battery cell stack 100, the gas may be discharged to the gas outlet 210 of the module frame 200 through the flame retardant member 300 at the top.

The flame retardant member 300 is located on top of the battery cell stack 100 and can be stored in the module frame 200 provided with the gas outlet 210. In this form, when one of the secondary battery cells ignites, gas and flame flow in the direction of the gas outlet 210. When gas and flame come into contact with the flame retardant member 300, the gas passes through, but the flame is removed. As a result, high temperature gas can be discharged to the top of the battery module 10 without passing the flame.

The flame retardant member 300 may be located inside or outside the module frame 200, or may be located such that a portion of the module frame 200 is interposed between two or more flame retardant sheets 310. 7 to 10 schematically show an example of a side cross-sectional view of the module frame 200 and the flame retardant member 300 according to an embodiment. Here, FIGS. 7 to 10 exemplarily show only the mesh-type sheet 320 interposed between two or more flame retardant sheets 310, but the various types of flame retardant members 300 described above may also be provided in the same manner. You can.

Referring to FIG. 7 according to one embodiment, the flame retardant member 300 may be located inside the module frame 200. That is, in one example, the battery module 10 of the battery pack 1 includes one or more battery cell stacks 100 including a plurality of secondary battery cells, one or more gas outlets 210, and a battery cell stack ( 100) and a flame retardant member 300 located inside the frame module 200 so as to contact the module frame 200 and the gas outlet 210, and each of the flame retardant members 300 includes one or more holes. It may be in a form including two or more flame retardant sheets 310 and a mesh-type sheet 320 interposed between two or more flame retardant sheets 310.

Referring to FIGS. 8 and 9 according to another embodiment, the flame retardant member 300 may be positioned so that a portion of the module frame 200 is interposed between two or more flame retardant sheets 310. In this example, the battery module 10 of the battery pack 10 includes one or more battery cell stacks 100 including a plurality of secondary battery cells, one or more gas outlets 210, and a battery cell stack 100. ) and a module frame 200 and a flame retardant member 300 for accommodating the flame retardant member 300, between two or more flame retardant sheets 310 and two or more flame retardant sheets 310, each including one or more holes. It includes a mesh-type sheet 320 interposed therein, and the side of the module frame 200 including the gas outlet 210 may be sandwiched between two or more flame retardant sheets 310.

Referring to FIG. 10 according to another embodiment, the flame retardant member 300 may be located outside the module frame 200. That is, in one example, the battery module 10 of the battery pack 1 includes one or more battery cell stacks 100 including a plurality of secondary battery cells, one or more gas outlets 210, and a battery cell stack ( 100) and a flame retardant member 300 located outside the frame module 200 so as to contact the module frame 200 and the gas outlet 210, and each of the flame retardant members 300 includes one or more holes. It may be in a form including two or more flame retardant sheets 310 and a mesh-type sheet 320 interposed between two or more flame retardant sheets 310.

The description of the present specification described above is for illustrative purposes, and a person skilled in the art to which an aspect of the present specification pertains can easily transform it into another specific form without changing the technical idea or essential features described in the present specification. You will be able to understand it. Therefore, the embodiments described above should be understood in all respects as illustrative and not restrictive. For example, each component described as unitary may be implemented in a distributed manner, and similarly, components described as distributed may also be implemented in a combined form.

The scope of the present specification is indicated by the claims, and all changes or modified forms derived from the meaning and scope of the claims and their equivalent concepts should be construed as being included in the scope of the present specification.

1: Battery pack
10: Battery module
20: case
30: control module
100: Battery cell laminate
200: module frame
210: gas outlet
220: coupling hole
230: end plate
300: Flame retardant member
310: Flame retardant sheet
311: First flame retardant sheet
312: Second flame retardant sheet
320: mesh sheet
321: first mesh sheet
322: Second mesh sheet

Claims (5)

A battery module including one or more battery cell stacks including a plurality of secondary battery cells and a module frame for housing the battery cell stacks;
A case storing one or more battery modules; and
Flame retardant member;
Including,
The flame retardant member,
a first mesh-like sheet; and
a flame retardant sheet or a second mesh-type sheet including one or more holes;
A battery pack containing. According to paragraph 1,
The flame retardant member includes two or more of the flame retardant sheets,
A battery pack, wherein the mesh-type sheet is sandwiched between two or more flame retardant sheets. According to paragraph 1,
The flame retardant member includes the first and second mesh sheets,
A battery pack wherein the first and second mesh sheets have different sieve sizes. According to paragraph 3,
The flame retardant member includes the flame retardant sheet, first and second mesh sheets,
The battery pack, wherein the flame retardant sheet is interposed between the first and second mesh-type sheets. According to paragraph 1,
The flame retardant sheet contains mica,
A battery pack, wherein the mesh sheet includes one or more selected from the group consisting of aluminum, copper, iron, stainless steel, brass, and bronze.