Battery module and battery pack including the battery module

Abstract

A battery module and a battery pack including the battery module are disclosed. The battery module according to an exemplary embodiment of the present invention includes: a battery cell stack including one or more battery cells each having an electrode lead; a module frame accommodating the battery cell stack; and a flame retardant cover sheet, which is disposed between the battery cell stack and the module frame and covers a portion of the battery cell stack, wherein the flame retardant cover sheet is disposed so as not to cover a portion of any one of the front and rear portions of the battery cell stack in the length direction of the battery cell stack. Therefore, when a fire occurs in the battery module, the battery module can guide the discharge direction of heat and flames in a specific direction.

Description

Technical Field

[0001] The present invention relates to a battery module and a battery pack including the same, and more particularly, to a battery module capable of controlling the emission direction of flame even when thermal runaway occurs, and a battery pack including the same. Background Art

[0002] In modern society, as the use of portable devices such as mobile phones, laptop computers, camcorders, and digital cameras has become the norm, the development of technologies related to these mobile devices has become active. In addition, rechargeable secondary batteries are a measure to solve the air pollution caused by existing gasoline vehicles using fossil fuels, and are used as power sources for electric vehicles (EVs), hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (P-HEVs), etc., making the development of secondary batteries increasingly necessary.

[0003] Secondary batteries currently available on the market include nickel-cadmium batteries, nickel-metal hydride batteries, nickel-zinc batteries, lithium secondary batteries, etc. Among them, compared with nickel-based secondary batteries, lithium secondary batteries have attracted attention because they have the advantages of free charge and discharge due to almost no memory effect, very low self-discharge rate and very high energy density.

[0004] Lithium secondary batteries primarily use lithium-based oxides and carbonaceous materials as positive and negative electrode active materials, respectively. They consist of an electrode assembly, in which a positive electrode plate and a negative electrode plate, each coated with a positive and negative electrode active material, are arranged with a separator interposed therebetween; and a housing material, i.e., a battery case, that seals and houses the electrode assembly and the electrolyte.

[0005] Generally, lithium secondary batteries can be divided into can-type secondary batteries in which an electrode assembly is built in a metal can, and pouch-type secondary batteries in which an electrode assembly is built in a pouch of an aluminum laminate sheet, according to the shape of a casing material.

[0006] In the case of secondary batteries for small devices, two or three battery cells are provided, but in the case of secondary batteries for medium and large devices such as automobiles, battery modules with multiple battery cells electrically connected are used. Multiple battery cells are connected in series or in parallel to form a battery cell aggregate, so that the battery module has improved capacity and output. In addition, one or more battery modules can be installed together with various control and protection systems such as a battery management system (BMS) and a cooling system to form a battery pack.

[0007] When a battery pack is constructed by connecting multiple battery cells in series or parallel, a battery module consisting of at least one battery cell is first constructed. As a general method, the battery pack is constructed by adding other components using at least one battery module. The number of battery modules included in the battery pack or the number of battery cells included in the battery module can be set differently depending on the required output voltage or charge / discharge capacity.

[0008] In addition, in the case of a battery pack formed by using a plurality of battery modules, when thermal runaway occurs due to abnormal operation such as overcharging, high-temperature gas and flames are emitted to the outside of the battery modules in some modules among the plurality of battery modules. When the generated flames are discharged to the outside at will, it is difficult to control the flames and it is impossible to predict in which direction the flames are discharged, thereby posing a problem that all adjacent mechanical devices may be damaged together.

[0009] The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art. Summary of the Invention

[0010] The present invention is directed to providing a battery module capable of guiding the discharge direction of heat and flame in a specific direction when a fire occurs in the battery module, and a battery pack including the battery module.

[0011] However, the objects to be achieved in the exemplary embodiments of the present invention are not limited to the aforementioned objects, and various extensions can be made within the scope of the technical concept included in the present invention.

[0012] An exemplary embodiment of the present invention provides a battery module, comprising: a battery cell stack including one or more battery cells each having an electrode lead; a module frame accommodating the battery cell stack; and a flame-retardant cover sheet, the flame-retardant cover sheet being arranged between the battery cell stack and the module frame and covering a portion of the battery cell stack, wherein the flame-retardant cover sheet is arranged so as not to cover a portion of either the front or rear portion of the battery cell stack in a longitudinal direction of the battery cell stack.

[0013] In a portion of the front portion and the rear portion that is completely covered by the flame-retardant cover sheet, the flame-retardant cover sheet may include one or more openings that are opened to lead the electrode lead to the outside.

[0014] The flame retardant cover sheet may include a flame retardant material including at least one selected from silicon and mica.

[0015] The battery module may further include: a pair of end plates arranged in the end portions of the battery cell stack in the length direction, wherein the flame retardant cover sheet may be located between the end plates and the battery cell stack in the portions of the front and the rear that are completely covered by the flame retardant cover sheet.

[0016] In portions of the front and rear portions that are not covered by the flame-retardant cover sheet, the flame-retardant cover sheet may not be provided between the end plates and the battery cell stack.

[0017] The flame retardant cover sheet may include a plurality of vent holes in at least a portion of the flame retardant cover sheet.

[0018] The plurality of vent holes may be provided to correspond to an upper surface of the battery cell stack.

[0019] When a fire occurs in the battery cell stack, the flame may be directed to the front portion or the rear portion that is not covered by the flame-retardant cover sheet.

[0020] The battery module may further include a bus bar frame disposed between the flame-retardant cover sheet and an upper surface of the module frame and including bus bars electrically connected to the electrode leads.

[0021] Another exemplary embodiment of the present invention provides a battery pack including: at least one battery module; and a battery pack case configured to enclose the at least one battery module.

[0022] According to exemplary embodiments of the present invention, a battery module capable of guiding the discharge direction of heat and flame in a specific direction when a fire occurs in the battery module and a battery pack including the battery module may be provided. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 is a perspective view of a battery module according to an exemplary embodiment of the present invention.

[0024] Figure 2 yes Figure 1 An exploded perspective view of the battery module.

[0025] Figure 3 It is illustrated in Figure 2 Illustration of the direction of flames in a battery module with a battery cell stack and a flame-retardant cover sheet combined.

[0026] Figure 4 It is a diagram Figure 1 Illustration of the direction of the flame in the battery module.

[0027] Figure 5is a diagram illustrating a state in which a battery cell stack is combined with a flame-retardant cover sheet in a battery module according to another exemplary embodiment of the present invention. DETAILED DESCRIPTION

[0028] The present invention will be described more fully hereinafter with reference to the accompanying drawings, in which exemplary embodiments of the invention are shown.

[0029] However, the present invention can be implemented in various forms and is not limited to the following embodiments.

[0030] Accordingly, the drawings and description are to be regarded as illustrative in nature and not restrictive. Like reference numerals refer to like elements throughout the application.

[0031] In addition, for the sake of understanding and ease of description, the size and thickness of each structure shown in the drawings are arbitrarily shown, but the present invention is not limited thereto. In the drawings, the thickness of layers, films, plates, regions, etc. are exaggerated for the sake of clarity. In the drawings, the thickness of some layers and regions are exaggerated for the sake of understanding and ease of description.

[0032] Furthermore, it will be understood that when an element, such as a layer, film, region, or plate, is referred to as being "on" another element, the element may be directly on the other element or intervening elements may be present. Conversely, when an element is referred to as being "directly on" another element, this means that no other intervening elements are present. Furthermore, in this application, the term "on..." refers to being above or below a target portion, and does not necessarily mean being on the upper side of the target portion relative to the direction of gravity.

[0033] In addition, unless explicitly described to the contrary, the word “comprise” or “comprising” will be understood to imply the inclusion of stated elements but not the exclusion of any other elements.

[0034] Figure 1 is a perspective view of a battery module according to an exemplary embodiment of the present invention, Figure 2 yes Figure 1 An exploded perspective view of the battery module. Figure 3 It is illustrated in Figure 2 A diagram showing the direction of flames in a battery module in which a battery cell stack is combined with a flame retardant cap sheet. Figure 4 It is a diagram Figure 1 Illustration of the direction of the flame in the battery module.

[0035] Reference Figures 1 to 4According to an exemplary embodiment of the present invention, a battery module 100 includes: a battery cell stack 110 including one or more battery cells, a module frame 200 accommodating the battery cell stack 110, and a pair of end plates 300 located at both ends of the battery cell stack 110 in a length direction and coupled to an opening of the module frame 200.

[0036] The battery cell stack 110 is a collection of secondary batteries including a plurality of battery cells 112. The battery cell stack 110 may include a plurality of battery cells 112, and each battery cell 112 includes an electrode lead 114. The battery cell 112 may be a pouch-type battery cell having a plate shape, but is not limited thereto. The electrode lead 114 is a positive electrode lead or a negative electrode lead, and the end of the electrode lead 114 of each battery cell 112 may be bent in one direction so as to contact the end of the electrode lead of another adjacent battery cell 112. The two electrode leads 114 in contact with each other may be fixed by welding or the like, so that the battery cells 112 within the battery cell stack 110 can be electrically connected.

[0037] Furthermore, the busbar frame 500 housed in the module frame 200 may be provided together with the battery cell stack 110. The busbar frame 500 may include an upper frame 510 located above the battery cell stack 110, a front frame 520 located on the front surface of the battery cell stack 110, and a rear frame 530 located on the rear surface of the battery cell stack 110. Busbars 540 connected to the electrode leads 114 of the battery cells constituting the battery cell stack 110 may be mounted on the front frame 520 and the rear frame 530. In this case, the flame-retardant cover sheet 400, to be described below, may be coupled to the busbar frame 500 while being formed to cover a portion of the battery cell stack 110. Therefore, the upper frame 510 of the busbar frame 500 is provided on the flame-retardant cover sheet 400, and the front frame 520 is provided to cover one end portion of the battery cell stack 110 covered by the flame-retardant cover sheet 400. Particularly, in this case, the bus bar 540 provided in the front frame 520 may be combined with the electrode lead 114 led out to the outside through the opening 410 of the flame-retardant cover sheet 400 .

[0038] A plurality of battery cells 112 are stacked vertically so that the electrode leads 114 are aligned in one direction, thereby forming a battery cell stack 110. The battery cell stack 110 is housed in a module frame 200, which includes at least one opening that is open in the length direction of the battery cell stack 110. In this case, the electrode leads 114 are led out to the outside of the module frame 200 through the opening, and the led-out electrode leads 114 are respectively coupled to the front frame 520 and the rear frame 530 of the bus bar frame 500, thereby being electrically connected to the installed bus bars 540. Here, the bus bar frame 500 may be made of an insulating material, such as a non-conductive synthetic resin, and the bus bars 540 may be made of a conductive metal material.

[0039] The battery module 100 may include a flexible printed circuit board (FPCB) (not shown) that extends and is mounted on the upper portion of the battery cell stack 110 along the length of the module frame 200 to sense the battery cells 112. Furthermore, the battery module 100 may include various electronic components, such as an internal circuit board (ICB) and a battery management system (BMS). Electronic components such as the ICB and BMS may be electrically connected to the plurality of battery cells 112.

[0040] In the battery module 100 according to the present exemplary embodiment, the module frame 200 may be formed to cover four surfaces of the battery cell stack 110 except for two side end portions. Figure 2 In the embodiment, the battery cell stack 110 may have an upper surface and a bottom surface at the upper and lower parts respectively along the z-axis direction, the upper surface of the module frame 200 may be located at a position corresponding to the upper surface of the battery cell stack 110, the lower surface of the module frame 200 may be located at a position corresponding to the bottom surface of the battery cell stack 110, and a pair of side surfaces corresponding to the side surfaces of the battery cell stack 110 may be located between the upper surface and the lower surface. In this case, the module frame 200 may be as shown in FIG. Figure 2 The module frame is shown as having a rectangular tube shape, but is not limited thereto. It may also have a structure in which a U-shaped frame formed by a lower surface and a pair of side surfaces perpendicularly connected to both sides of the lower surface is combined with an upper plate forming the upper surface. Furthermore, the module frame may have a structure in which an inverted U-shaped frame formed by an upper surface and two side surfaces is combined with a lower plate forming the lower surface, but is not particularly limited thereto.

[0041] The module frame 200 may be made of a metal material. The metal material may be one or more selected from steel and aluminum. End plates 300 are respectively bonded to the two open ends of the module frame 200. The end plates 300 may be made of a metal material to provide the strength to protect internal components such as the battery cell stack 110 and the busbar frame 500. The metal end plates 300 may be bonded to the metal module frame 200 by welding or other methods.

[0042] In addition, a flame retardant cover sheet 400 is included between the battery cell stack 110 and the module frame 200. The flame retardant cover sheet 400 may be formed to cover one side of the battery cell stack 110 in the length direction without covering the other side. Figure 2 The front and rear portions are parallel to the x-axis direction in the direction indicated by F and R. In this exemplary embodiment, Figure 2 The diagram illustrates a configuration in which the flame-retardant cover sheet 400 covers the front portion F, but the present invention is not limited thereto, and the flame-retardant cover sheet 400 may cover the rear portion R. The battery cell stack 110 may be configured so that the direction in which the generated flame is to be discharged is exposed, that is, not covered by the flame-retardant cover sheet 400 to be described below.

[0043] In the portion covered by the flame retardant cover sheet 400, that is, Figure 2 In the front portion F of the battery cell stack 110, the flame-retardant cover sheet 400 is formed to cover the portion facing the end plate 300 in addition to the upper surface, lower surface, and side surface of the battery cell stack 110. Therefore, the front portion F may be in a state in which the flame-retardant cover sheet 400 is disposed between the end plate 300 and the battery cell stack 110. In this case, one or more openings 410 may be formed in the flame-retardant cover sheet 400 to correspond to the positions of the electrode leads 114, thereby leading the electrode leads 114 included in the battery cells 112 to the outside.

[0044] In the portion not covered by the flame retardant cover sheet 400, that is, Figure 2 In the rear portion R of the battery cell stack 110, a portion of the upper surface, a portion of the lower surface, and a portion of the side surface are formed so as not to be covered by the flame-retardant cover sheet 400, and thus the portion facing the end plate 300 is naturally formed so as not to be covered. That is, the length (FR direction) of the flame-retardant cover sheet 400 is formed to be shorter than the length of the battery cell stack 110, thereby forming a structure with one end open, so that when the battery cell stack 110 is accommodated in the flame-retardant cover sheet 400, a portion of the battery cell stack 110 is exposed along the periphery of the flame-retardant cover sheet 400 in the rear portion R, as shown in FIG. Figure 2When manufacturing the battery module 100 , after covering the flame-retardant cover sheet 400 on the battery cell stack 110 , the flame-retardant cover sheet 400 is combined with the above-mentioned bus bar frame 500 and the electrode lead 114 and the bus bar 540 are welded.

[0045] The flame-retardant cover sheet 400 may be formed of a sheet made of a flame-retardant material. In this case, the flame-retardant material may include at least one selected from silicon and mica. However, the flame-retardant material is not limited thereto, and any commercially available material that has flame retardancy and can be processed into a sheet shape may be appropriately selected and used.

[0046] When a flame is generated inside the battery cell stack 110, the portion covered by the flame retardant cover sheet 400 made of a flame retardant material can prevent the flame from spreading to the corresponding portion. Figure 3 and Figure 4 As shown in , the flame and exhaust gas generated in the battery cell stack 110 are discharged to the portion not covered by the flame retardant cover sheet 400, that is, the rear portion R, thereby preventing the flame and exhaust gas from being discharged to the outside at will, but guiding and discharging them in one direction. Through the aforementioned construction, the direction of the flame and exhaust gas can be guided in a predetermined direction. In the battery pack and device in which the battery module 100 is provided, the discharge direction is directed to a position in which there are relatively few adjacent modules or components, so that even if a fire starts in any one module, the flame can be prevented from spreading to other adjacent modules or components as much as possible. In addition, even if there is another module or component in the discharge direction, the discharge of the flame and exhaust gas is guided only in one direction, so that damage to the module provided in the other direction can be prevented and delayed as much as possible. Therefore, the safety of the battery module 100 and the battery pack including the battery module can be improved by controlling the direction of the flame in the battery module 100.

[0047] Next, we will refer to Figure 5 Another exemplary embodiment of the present invention is described.

[0048] Figure 5 is a diagram illustrating a state in which a battery cell stack is combined with a flame-retardant cover sheet in a battery module according to another exemplary embodiment of the present invention.

[0049] Compared with the aforementioned exemplary embodiment, Figure 5 The exemplary embodiment of FIG. 5 is different only in the shape of the flame retardant cover sheet 400 , and the rest are the same, so the description of the same parts will be omitted.

[0050] like Figure 5As shown in FIG, in another exemplary embodiment of the present invention, a plurality of vent holes 420 are included in at least a portion of the flame retardant cover sheet 400. More specifically, the plurality of vent holes 420 may be provided to correspond to the upper surface of the battery cell stack 110. In addition, the plurality of vent holes 420 are shown as circular in shape, but the shape is not particularly limited. Figure 5 As shown in FIG, the plurality of vent holes 420 may be formed to correspond to the entire upper surface of the battery cell stack 110, but is not limited thereto and may also be formed to correspond to a portion of the upper surface of the battery cell stack 110. Figure 5 As shown in FIG, the plurality of vent holes 420 may be regularly arranged in rows, but is not limited thereto, and the plurality of vent holes 420 may also be randomly arranged and formed.

[0051] By providing the vent holes 420, flames and gases that may otherwise accumulate in the flame-retardant cover sheet 400 can be discharged separately from flames and gases discharged to the rear portion R where the flame-retardant cover sheet 400 is not formed. In other words, the vent holes 420 prevent flames from accumulating within the flame-retardant cover sheet 400, thereby preventing explosive heat conduction. Consequently, the safety of the battery module 100 can be further improved.

[0052] As described above, according to exemplary embodiments of the present invention, the flame and exhaust gas can be directed in a predetermined direction by the flame-retardant cover sheet 400, which only covers a portion of the battery cell stack 110. This allows the exhaust gas to be directed toward a location with relatively few adjacent modules or components in a battery pack or device in which the battery module 100 is installed. This allows, even if a fire starts in any one module, to minimize the spread of the flame to other adjacent modules or components. Furthermore, even if another module or component is located in the exhaust direction, the exhaust gas and flame are directed in only one direction, minimizing the risk of damage to modules located in the opposite direction. Therefore, controlling the direction of the flame in the battery module 100 can improve the safety of the battery module 100 and the battery pack in which it is installed. Furthermore, the multiple vents 420 provided in the flame-retardant cover sheet 400 prevent flames from accumulating within the flame-retardant cover sheet 400, thereby preventing explosive heat conduction.

[0053] In addition, the battery module according to the exemplary embodiment of the present invention may be packaged in one or more pack cases to form a battery pack.

[0054] The battery module and the battery pack including the battery module can be applied to various devices. As the device, vehicles such as electric bicycles, electric vehicles, and hybrid vehicles can be applied, but the present invention is not limited thereto. The present invention can be applied to various devices that can use the battery module and the battery pack including the battery module, which also falls within the scope of the present invention.

[0055] Although the exemplary embodiments of the present invention have been described in detail, the scope of the present invention is not limited to these embodiments. Various changes and modifications made by those skilled in the art using the basic concept of the present invention defined in the appended claims should be interpreted as belonging to the scope of the present invention.

[0056] [Explanation of Reference Numerals]

[0057] 100: Battery module

[0058] 110: Battery cell stack

[0059] 114: Electrode lead

[0060] 200: Module Framework

[0061] 300: End plate

[0062] 400: Flame retardant cover sheet

[0063] 410: Opening

[0064] 420: Ventilation hole.

Claims

1. A battery module, comprising: a battery cell stack including one or more battery cells each having an electrode lead; a module frame accommodating the battery cell stack; and a flame retardant cover sheet disposed between the battery cell stack and the module frame and covering a portion of the battery cell stack, wherein the flame-retardant cover sheet is arranged so as not to cover a portion of any one of the front and rear portions of the battery cell stack in the length direction of the battery cell stack, wherein in the portion of the front and rear portions that is completely covered by the flame-retardant cover sheet, the flame-retardant cover sheet is formed to cover the upper surface, the lower surface, the side surface and the side end portions in the length direction of the battery cell stack, wherein in the portion of the front portion and the rear portion not covered by the flame-retardant cover sheet, the flame-retardant cover sheet is formed not to cover the upper surface, the lower surface, the side surface and the side end portions in the length direction of the battery cell stack, so that a portion of the battery cell stack is exposed along the periphery of the flame-retardant cover sheet, and When a fire occurs in the battery cell stack, the flame is directed to the front or rear portion not covered by the flame-retardant cover sheet, so that the discharge of the flame and exhaust gas is directed only in one direction, which is directed to a position with relatively few adjacent modules or components.

2. The battery module according to claim 1, wherein: In a portion of the front portion and the rear portion that is completely covered by the flame-retardant cover sheet, the flame-retardant cover sheet includes one or more openings that are opened to lead out the electrode lead to the outside.

3. The battery module according to claim 1, wherein: The flame retardant cover sheet includes a flame retardant material, and the flame retardant material includes at least one selected from silicon and mica.

4. The battery module according to claim 1, further comprising: A pair of end plates provided at the ends of the battery cell stack in the length direction, In the portion of the front portion and the rear portion that is completely covered by the flame-retardant cover sheet, the flame-retardant cover sheet is located between the end plate and the battery cell stack.

5. The battery module according to claim 4, wherein: In portions of the front portion and the rear portion that are not covered by the flame-retardant cover sheet, the flame-retardant cover sheet is not provided between the end plate and the battery cell stack.

6. The battery module according to claim 1, wherein: The flame retardant cover sheet includes a plurality of vent holes in at least a portion of the flame retardant cover sheet.

7. The battery module according to claim 6, wherein: The plurality of vent holes are disposed to correspond to an upper surface of the battery cell stack.

8. The battery module according to claim 1, further comprising: A bus bar frame is disposed between the flame retardant cover sheet and an upper surface of the module frame and includes bus bars electrically connected to the electrode leads.

9. A battery pack comprising: at least one battery module according to any one of claims 1 to 8; and A battery pack housing is configured to enclose the at least one battery module.

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