Battery module and battery pack including the same

Abstract

A battery module according to an embodiment of the present invention includes: a battery cell stack including a plurality of battery cells stacked in a first direction; and an external member that makes a central portion on a lower surface of the battery cell stack open and surrounds an outer surface of the battery cell stack, wherein one end of the external member is attached to one side portion of the lower surface of the battery cell stack, and the other end of the external member is attached to the other side portion of the lower surface of the battery cell stack.

Description

Technical Field

[0001] The present disclosure relates to a battery module and a battery pack including the battery module, and more particularly, to a battery module having improved cooling performance while improving the swelling phenomenon of battery cells and a battery pack including the battery module. Background Art

[0002] With the development of technology and the increasing demand for mobile devices, the demand for batteries as an energy source is rapidly increasing. In particular, secondary batteries, as an energy source for power-driven devices such as electric bicycles, electric vehicles, and hybrid electric vehicles, and as an energy source for mobile devices such as mobile phones, digital cameras, laptop computers, and wearable devices, have attracted considerable attention.

[0003] Small mobile devices use one or several battery cells for each device, while medium or large-sized devices such as vehicles require high power and large capacity. Therefore, medium or large-sized battery modules using a plurality of battery cells electrically connected to each other are used.

[0004] Since medium or large-sized battery modules are preferably manufactured to have as small a size and weight as possible, prismatic batteries, pouch batteries, etc., which can be stacked in a highly integrated manner and have a small weight relative to the capacity, are mainly used as the battery cells of medium or large-sized battery modules. At the same time, in order to protect the battery cell stack from external impacts, heat, or vibrations, the battery module may include a module frame that is open on its front and rear sides and houses the battery cell stack in an internal space.

[0005] Figure 1 is a perspective view of a conventional battery module. Figure 2 is Figure 1 an exploded perspective view of the battery module. Figure 3 is a view showing a part of a cross-section taken along the cutting line A-A of Figure 1 the battery module.

[0006] Referring to Figure 1 and Figure 2 , the conventional battery module 10 includes: a battery cell stack 12 in which a plurality of battery cells 11 are stacked in one direction; and an external member 30 for housing the battery cell stack 12. Here, the external member 30 is open in its front and rear surfaces, so that the front and rear surfaces of the battery cell stack 12 housed in the external member 30 are open.

[0007] Here, the battery module 10 is mounted on a thermally conductive resin layer 14 formed on a battery pack frame member (not shown). Therefore, the conventional battery module 10 is configured such that the external member 30 is located between the battery cell stack 12 and the thermally conductive resin layer 14.

[0008] Reference Figure 3 , the compression gasket is located between the battery cell stack 12 and the external member 30. Generally speaking, however, the problem with the compression gasket is that it is limited in absorbing deformation in the width direction of the battery module 10.

[0009] Reference Figure 3 , the conventional battery module 10 has a structure in which the lower part of the battery cell stack 12 is indirectly cooled via the heat-conductive resin layer 14, and the heat generated in the battery cells 11 flows to the heat-conductive resin layer 14 via the external member 30. Here, the problem with the conventional battery module 10 is that heat transfer is inhibited because an air layer is formed between the external member 30 and the battery cell stack 12 or between the external member 30 and the heat-conductive resin layer 14. Considering that the temperature of the battery cells 11 is one of the factors limiting the battery output, the local temperature rise occurring in the battery cells 11 is very likely to limit the battery output at an early stage, so improvements are needed. In addition, with the recent expansion of the battery module 10, the number of battery cells 11 stacked in the module increases, and the cooling deviation between the battery cells 11 further deepens.

[0010] Therefore, it is necessary to develop a battery module and a battery pack including the battery module that can prevent the bulging phenomenon in the battery cell stack 12 while improving the cooling performance of the heat generated in the battery cell stack 12. Summary of the Invention

[0011] Technical Problem

[0012] An object of the present disclosure is to provide a battery module having improved bulging phenomenon of battery cells and improved cooling performance, and to provide a battery pack including the battery module.

[0013] The object of the present disclosure is not limited to the above object, and those skilled in the art should clearly understand other objects not described herein according to the following detailed description and the drawings.

[0014] Technical Solution

[0015] According to an embodiment of the present disclosure, there is provided a battery module including: a battery cell stack including a plurality of battery cells stacked along a first direction; and an external member surrounding an outer surface of the battery cell stack, wherein a central portion of a lower surface of the battery cell stack is open, wherein one end of the external member is attached to one side portion of the lower surface of the battery cell stack, and wherein the other end of the external member is attached to the other side portion of the lower surface of the battery cell stack.

[0016] The outer surface of the external member of the battery module is exposed to the outside, and a central portion of the lower surface of the battery cell stack located between one end and the other end of the external member may be exposed to the outside.

[0017] The external member may be made of an elastic material.

[0018] The external member may be formed such that a film made of an elastic material wraps around the outer surface of the battery cell stack from one side of the lower surface of the battery cell stack and wraps upward to the other side of the lower surface of the battery cell stack.

[0019] The battery module further includes compression pads located on two side surfaces of the battery cell stack, wherein the compression pads are located between the external member and the outer surface of the battery cell stack, and the external member can press the battery cell stack in a first direction.

[0020] The external member presses the upper surface of the battery cell stack in a second direction, and the second direction may be perpendicular to the first direction.

[0021] The second direction may be the width direction of the plurality of battery cells.

[0022] The compression pads may extend along the side surfaces of the battery cell stack.

[0023] According to another embodiment of the present disclosure, there is provided a battery pack including the above-described battery module.

[0024] The battery pack includes: a lower battery pack frame on which at least two of the battery modules are mounted; an upper battery pack frame that covers an upper portion of the at least two battery modules; and a thermally conductive resin layer formed on the lower battery pack frame, wherein the central portion of the lower surface of the battery cell stack may be in contact with the thermally conductive resin layer.

[0025] The lower battery pack frame includes a plurality of module areas, and the battery modules may be mounted in the module areas.

[0026] The thermally conductive resin layer may be formed on the module areas respectively.

[0027] The size of the thermally conductive resin layer may be equal to the size of the central portion of the lower surface of the battery cell stack.

[0028] A side surface of one end of the external member may be in contact with one side surface of the thermally conductive resin layer, and a side surface of the other end of the external member may be in contact with the other side surface of the thermally conductive resin layer.

[0029] Advantageous Effects

[0030] According to an embodiment of the present disclosure, a battery module and a battery pack including the battery module can be provided. The battery module includes an external member that wraps an outer surface of a battery cell stack, wherein a central portion of a lower surface of the battery cell stack is open, thereby having improved cooling performance while improving the bulging phenomenon of the battery cells.

[0031] The effects of the present disclosure are not limited to the above effects, and those skilled in the art can clearly understand other additional effects not described above according to the description of the appended claims. Description of the Drawings

[0032] Figure 1 is a perspective view of a conventional battery module;

[0033] Figure 2 is Figure 1 an exploded perspective view of the battery module;

[0034] Figure 3 is a view showing a part of a cross-section taken along the Figure 1 cutting line A-A of;

[0035] Figure 4 is a perspective view of a battery module according to an embodiment of the present disclosure;

[0036] Figure 5 is Figure 4 an exploded perspective view of the battery module;

[0037] Figure 6 is a cross-sectional view taken along the Figure 4 cutting line B-B of;

[0038] Figure 7 is Figure 4 an exploded perspective view of a battery cell stack included in the battery module;

[0039] Figure 8 is a perspective view of a battery pack according to an embodiment of the present disclosure;

[0040] Figure 9 is Figure 8 an exploded perspective view of the battery pack;

[0041] Figure 10 is a cross-sectional view taken along the Figure 8 cutting line C-C of; and

[0042] Figure 11 is an enlarged view of a part of a cross-sectional view showing Figure 10 . DETAILED DESCRIPTION

[0043] Hereinafter, various embodiments of the present disclosure will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily implement these embodiments. The present disclosure can be modified in various different ways and is not limited to the embodiments set forth herein.

[0044] Portions not relevant to the description will be omitted to clearly describe the present disclosure, and throughout the specification, like reference numerals denote like elements.

[0045] In addition, in the drawings, for ease of description, the dimensions and thicknesses of each element are arbitrarily shown, and the present disclosure is not necessarily limited to those shown in the drawings. In the drawings, for clarity, the thicknesses of layers, regions, etc. are exaggerated. In the drawings, for ease of description, the thicknesses of certain layers and regions are shown exaggeratedly.

[0046] In addition, throughout the specification, when a part is referred to as "including" a certain component, it means that the part may further include other components without excluding other components, unless otherwise specified.

[0047] In addition, throughout the specification, when referred to as "plane", it means the case of observing the target part from the upper side, and when referred to as "cross-section", it means the case of observing the target part from the cross-section side cut vertically.

[0048] Hereinafter, a battery module according to an embodiment of the present disclosure will be described. However, the description herein is based on the front surface among the front and rear surfaces of the battery module, and is not necessarily limited thereto. Even in the case of the rear surface, a description with the same or similar content can be given.

[0049] Figure 4 is a perspective view of a battery module according to an embodiment of the present disclosure. Figure 5 is Figure 4 an exploded perspective view of the battery module.

[0050] Referring to Figure 4 and Figure 5 , the battery module 100 includes: a battery cell stack 120 in which a plurality of battery cells 110 are stacked in a first direction; an external member 300 that surrounds the battery cell stack 120; and a sensing member (not shown) that covers the front and rear surfaces of the battery cell stack.

[0051] The battery cell stack 120 enclosed by the outer member 300 is formed by stacking a plurality of battery cells 110, and the battery cells 110 are preferably pouch-type battery cells. The battery cells 110 can be produced by accommodating an electrode assembly in a bag-shaped housing of a laminate sheet including a resin layer and a metal layer and then heat-sealing a sealed portion of the bag-shaped housing. A plurality of battery cells 110 can be configured, and the plurality of battery cells 110 are stacked and electrically connected to each other to form the battery cell stack 120.

[0052] Next, the outer member 300 will be described in more detail.

[0053] Figure 6 is a cross-sectional view taken along the Figure 4 cutting line B-B.

[0054] Referring to Figures 4 to 6 , the outer member 300 can enclose the outer surface of the battery cell stack 120. The outer member 300 can enclose the outer surface of the battery cell stack 120, and a central portion of the lower surface of the battery cell stack 120 is open. That is, the outer member 300 encloses two side surfaces and an upper surface of the battery cell stack 120, and the front surface and the rear surface of the battery cell stack 120 are open, and the central portion of the lower surface can be open.

[0055] More specifically, in the battery module 100 of the present embodiment, one end 300a of the outer member 300 is attached to one side portion of the lower surface of the battery cell stack 120, and the other end 300b of the outer member 300 is attached to the other side portion of the lower surface of the battery cell stack 120. That is, the outer member extends from one end 300a of the outer member 300 to the other end 300b of the outer member 300 and can enclose two side portions, two side surfaces, and an upper surface of the lower surface of the battery cell stack 120.

[0056] In addition, the outer member 300 can be configured such that the outer surface of the outer member 300 is exposed in a state of enclosing the battery cell stack 120. That is, when the battery module 100 is mounted on the lower battery pack frame 1200 of the battery pack in the process described later, the outer member 300 can contact the lower battery pack frame 1200. Further, in the outer member 300, a central portion of the lower surface of the battery cell stack 120 located between one end 300a and the other end 300b of the outer member 300 can be exposed to the outside. That is, when the battery module 100 is mounted on the lower battery pack frame 1200 of the battery pack in the process described later, the outer member 300 can be in direct contact with the heat-conductive resin layer 1400 formed on the lower battery pack frame 1200.

[0057] Thus, in the external member 300 of the present embodiment, the central portion of the lower surface of the battery cell stack 120 is open to the outside, and the heat conductive resin layer 1400 described later can be in direct contact with the central portion of the lower surface of the battery cell stack 120 to directly cool the heat generated in the battery cell stack 120. That is, the external member 300 according to the present embodiment can further improve the cooling performance.

[0058] In addition, each of the two side surfaces and the upper and lower surfaces of the external member 300 may have a size corresponding to the size of the outer surface of the battery cell stack. In one embodiment, the sizes of the two side surfaces of the external member 300 may be equal to or smaller than the sizes of the side surfaces of the battery cell stack 120. In addition, the upper surface of the external member 300 may have a size equal to or smaller than the upper surface of the battery cell stack 120. In addition, one end 300a and the other end 300b of the external member 300 extend in the longitudinal direction of the lower surface of the battery cell stack 120 and may have a size equal to or smaller than the length of the lower surface of the battery cell stack 120.

[0059] Therefore, in the present embodiment, the external member 300 can press the battery cell stack 120 in a certain direction to wrap the battery cell stack 120. That is, the external member 300 presses the battery cells 110 included in the battery cell stack 120 in a certain direction, thereby preventing the bulging phenomenon of the battery cells and improving the dimensional stability of the battery module. In addition, through the process of the battery cell stack 120 being wrapped in the external member 300, the battery cell stack 120 is simultaneously pressed, so there is no need for a separate process of pressing the battery cell stack 120, which can simplify the process and the production line.

[0060] In one embodiment, the external member 300 may be made of an elastic material. The elastic material may be made of at least one of materials such as polyethylene (PE) and polytetrafluoroethylene (PTFE). Here, the external member 300 is formed such that a film made of an elastic material or a heat shrink tube wraps the outer surface of the battery cell stack 120 from one side of the lower surface of the battery cell stack and wraps upward to the other side of the lower surface of the battery cell stack 120. As one embodiment, the upper and lower surfaces and the two side surfaces (i.e., the outer surface of the battery cell stack 120) may be wrapped with a film or a heat shrink tube made of an elastic material, and then the portion of the film or the heat shrink tube covering the lower surface of the battery cell stack 120 may be removed to form the external member 300. However, this is not limited thereto, and any material having elasticity that can sufficiently press the battery cells 110 included in the battery cell stack 120 while effectively absorbing external shocks can be applied without limitation.

[0061] Therefore, in the present embodiment, the external member 300 can prevent the swelling phenomenon of the battery cells and improve the dimensional stability of the battery module. In addition, the external member 300 has the advantage that it is elastic itself, so it can minimize deformation in response to the volume change of the battery cells 110.

[0062] In addition, the outer surfaces of the battery cell stack 120 can be respectively attached to the inner surface of the external member 300. Here, the elastic material included in the external member 300 itself can have adhesiveness. In addition, the external member 300 and the battery cell stack 120 can be fixed by the frictional force between the inner surface of the external member 300 and the outer surface of the battery cell stack 120. In addition, a separate adhesive layer can be formed between the external member 300 and the battery cell stack 120.

[0063] In one embodiment, each adhesive layer can be formed of a tape, or can be coated with an adhesive and formed. More preferably, the adhesive layer is coated with an adhesive or made of a double-sided tape, so that the battery cell stack 120 and the external member 300 can be easily fixed. However, it is not limited thereto, and any material having adhesive properties capable of fixing the battery cells 110 to each other or the battery cells 110 and the external member 300 can be applied without limitation.

[0064] Therefore, the battery cell stack 120 can be stably accommodated in the external member 300.

[0065] In addition, referring to Figure 6 , the external member 300 presses the battery cell stack 120 in the first direction. More specifically, the first direction can be the width direction of the battery module 100, and this width direction can correspond to the stacking direction of the plurality of battery cells 110 in the battery cell stack 120.

[0066] Thus, the external member 300 presses the battery cell stack 120 in the same direction as the width direction of the battery module 100 or the stacking direction of the battery cells 110 to effectively prevent the swelling phenomenon of the battery module. In addition, the first compression pad 500 is located between the external member 300 and the battery cell stack 120 to effectively absorb the deformation occurring in the width direction of the battery module 100. In addition, the service life of the battery module 100 can also be improved.

[0067] In addition, the external member 300 presses the upper and lower surfaces of the battery cell stack in the second direction, and the second direction can be perpendicular to the first direction. More specifically, the second direction can be the width direction of the plurality of battery cells 110.

[0068] Therefore, even in the width direction of the battery cell 110 perpendicular to the width direction of the battery module 100, the external member 300 can be pressed with a predetermined pressure, so that the bulging phenomenon can be effectively prevented even in the width direction of the battery cell 110. In addition, the service life of the battery module 100 can be further improved.

[0069] Figure 7 is included in Figure 4 The exploded perspective view of the battery cell stack in the battery module.

[0070] Referring to Figure 6 and Figure 7 , according to the battery module 100 of the first embodiment, the compression pad 500 can be arranged such that it is located between the external member 300 and the outer surface of the battery cell stack 120. Here, the compression pad 500 can extend along the outer surface of the battery cell stack 120. In addition, the compression pad 500 can have a size equal to or smaller than the outer surface of the battery cell stack 120. In addition, both ends of the compression pad 500 can be in contact with the external member 300, or can be surrounded by the external member 300.

[0071] In addition, referring to Figure 6 and Figure 7 , according to another embodiment of the present disclosure, the battery cell stack 120 includes a first battery cell stack and a second battery cell stack, and the compression pad 500 can be located between the first battery cell stack and the second battery cell stack. In addition, the compression pad 500 can extend along the side surfaces of the first battery cell stack and the second battery cell stack.

[0072] In one embodiment, the compression pad 500 can be a pad made of polyurethane material. However, it is not limited thereto, and any material that can absorb the volume change during the expansion of the battery cell 110 can be applied.

[0073] Thus, the compression pad 500 can easily absorb the expansion generated in the battery cell 110 included in the battery cell stack 120, so that the external member 300 can assist in pressing the outer surface of the battery cell stack 120.

[0074] Figure 8 is the perspective view of a battery pack according to an embodiment of the present disclosure. Figure 9 is Figure 8 The exploded perspective view of the battery pack.

[0075] Referring to Figure 8 and Figure 9 , according to another embodiment of the present disclosure, the battery pack 1000 includes the above-mentioned battery module 100. At the same time, one or more battery modules 100 can be packaged in the battery pack frames 1200 and 1300 to form the battery pack 1000.

[0076] More specifically, the battery pack 1000 of the present embodiment includes: a lower battery pack frame 1200 on which at least two battery modules 100 are mounted; an upper battery pack frame 1300 that covers the upper portions of the at least two battery modules 100; and a thermally conductive resin layer 1400 formed on the lower surface of the lower battery pack frame 1200. Here, the at least two battery modules 100 are arranged in one direction to form a battery module arrangement body 1100. In addition, the lower battery pack frame 1200 includes a plurality of module areas, and the battery modules 100 can be mounted in the module areas. Here, since the battery modules 100 are mounted in the module areas, the central portion of the lower surface of the battery cell stack 120 and the thermally conductive resin layer 1400 can be in contact with each other.

[0077] Therefore, the heat generated in the battery cells 110 is transferred to the thermally conductive resin layer 1400 that is in direct contact with the central portion of the lower surface of the battery cell stack 120, so that the cooling performance of the battery modules 100 can be improved, and the cooling deviation between the battery cells 110 can also be reduced. In addition, the service life of the battery modules 100 can be further extended.

[0078] As an example, the thermally conductive resin layer 1400 can have a thermally conductive resin, which is applied to each module area of the lower battery pack frame 1200 before the battery modules 100 are mounted on the module areas of the lower battery pack frame 1200. Thereafter, as the thermally conductive resin cures, the thermally conductive resin layer 1400 can be formed.

[0079] Thus, as the thermally conductive resin cures, the lower surface of the battery module 100 can be stably fixed to the thermally conductive resin layer 1400.

[0080] Figure 10 is a sectional view taken along the cutting line C-C of Figure 8 Figure 11 is an enlarged view of a part of the sectional view showing Figure 10

[0081] More specifically, referring to Figure 10 and Figure 11 , the thermally conductive resin layer 1400 can be formed in each module area formed in the lower battery pack frame 1200. In addition, the thermally conductive resin layer 1400 can have the same size as the central portion of the lower surface of the battery cell stack 120.

[0082] ​​Accordingly, in each battery module 100 mounted on the lower battery pack frame 1200, the heat generated in the battery cells 110 can be respectively transferred to the heat-conductive resin layer 1400 that is in direct contact with the central portion of the lower surface of the battery cell stack 120. That is, the cooling performance of each battery module 100 is improved without heat transfer occurring between the battery modules 100, and the cooling deviation between the battery cells 110 in each battery module 100 can also be reduced. In addition, the service life of the battery module 100 can be further increased.

[0083] In addition, a side surface of one end 300a of the external member 300 is in contact with a side surface of the heat-conductive resin layer 1400, and a side surface of the other end 300b of the external member 300 can be in contact with the other side surface of the heat-conductive resin layer 1400.

[0084] Thus, as the heat-conductive resin cures, one end 300a and the other end 300b of the external member 300 located on the lower surface of the battery module 100 can be stably fixed to the heat-conductive resin layer 1400.

[0085] The above-described battery module and the battery pack including the same can be applied to various devices. Such devices can be applied to vehicle devices such as electric bicycles, electric vehicles, or hybrid vehicles, but the present disclosure is not limited thereto and is applicable to various devices that can use the battery module, which also falls within the scope of the present disclosure.

[0086] Although the present invention has been shown and described with reference to the preferred embodiments, the scope of the present disclosure is not limited thereto, and those skilled in the art can design many other variations and improvements without departing from the spirit and scope of the principles of the present invention defined in the appended claims.

[0087] Description of Reference Numerals

[0088] 100: Battery module

[0089] 110: Battery cell

[0090] 120: Battery cell stack

[0091] 300: External member

[0092] 500: Compression gasket

[0093] Cross-Reference to Related Applications

[0094] This application claims the benefit of Korean Patent Application No. 10-2020-0170442, filed with the Korean Intellectual Property Office on Dec. 8, 2020, the entire disclosure of which is incorporated herein by reference in its entirety.

Claims

1. A battery pack including a battery module, the battery module comprising: a battery cell stack including a plurality of battery cells stacked in a first direction, which is the width direction of the battery module; and an external member surrounding the outer surface of the battery cell stack, wherein a central portion of the lower surface of the battery cell stack is open, wherein one end of the external member in the first direction extends parallel to the lower surface of the battery cell stack toward the central portion of the lower surface of the battery cell stack and is attached to one side portion of the lower surface of the battery cell stack, and the other end of the external member in the first direction extends parallel to the lower surface of the battery cell stack toward the central portion of the lower surface of the battery cell stack and is attached to the other side portion of the lower surface of the battery cell stack, such that the central portion of the lower surface of the battery cell stack located between the one end and the other end of the external member is exposed to the outside, wherein the external member is made of an elastic material, dimensions of two side surfaces of the external member are equal to or smaller than dimensions of side surfaces of the battery cell stack, and a dimension of an upper surface of the external member is equal to or smaller than a dimension of an upper surface of the battery cell stack, wherein the battery pack further includes: a lower battery pack frame on which at least two battery modules are mounted; an upper battery pack frame covering an upper portion of the at least two battery modules; and a thermally conductive resin layer formed on the lower battery pack frame, wherein the central portion of the lower surface of the battery cell stack contacts the thermally conductive resin layer, and wherein the external member presses the battery cell stack in the first direction and presses an upper surface of the battery cell stack in a second direction perpendicular to the first direction.

2. The battery pack according to claim 1, wherein an outer surface of the external member of the battery module is exposed to the outside.

3. The battery pack according to claim 1, wherein the external member is formed such that a film made of an elastic material wraps around the outer surface of the battery cell stack from one side portion of the lower surface of the battery cell stack and wraps upward to the other side portion of the lower surface of the battery cell stack.

4. The battery pack according to claim 1, the battery module further includes compression pads located on two side surfaces of the battery cell stack, wherein the compression pads are located between the external member and the outer surface of the battery cell stack.

5. The battery pack according to claim 1, wherein the second direction is the width direction of the plurality of battery cells.

6. The battery pack according to claim 4, wherein the compression pads extend along the side surfaces of the battery cell stack.

7. The battery pack according to claim 1, wherein the lower battery pack frame includes a plurality of module regions, and the battery modules are mounted in the module regions.

8. The battery pack according to claim 7, wherein, the thermally conductive resin layer is formed on the module area respectively.

9. The battery pack according to claim 8, wherein, the size of the thermally conductive resin layer is equal to the size of the central portion of the lower surface of the battery cell stack.

10. The battery pack according to claim 9, wherein, a side surface of one end of the external member is in contact with a side surface of the thermally conductive resin layer, and a side surface of the other end of the external member is in contact with the other side surface of the thermally conductive resin layer.

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