Battery module and battery pack including the same

Abstract

A battery module according to one embodiment of the disclosure includes a battery cell stack formed by stacking a plurality of battery cells, a module frame to accommodate the battery cell stack, and a thermally conductive pad between an upper surface of the module frame and the battery cell stack, wherein the thermally conductive pad has a recess pattern corresponding to first end portions of the battery cells on a surface facing the battery cell stack.

Description

Technical Field

[0001] Cross-references to related applications

[0002] This application claims the benefit of Korean Patent Application No. 10-2020-0106089, filed with the Korean Intellectual Property Office on August 24, 2020, the disclosure of which is incorporated herein by reference in its entirety.

[0003] This disclosure relates to a battery module and a battery pack including the battery module, and more specifically, to a battery module having improved cooling performance and a battery pack including the battery module. Background Technology

[0004] With technological advancements and increasing demands for mobile devices, the need for rechargeable batteries as an energy source is rapidly growing. Consequently, research into batteries capable of meeting diverse requirements is emerging.

[0005] Secondary batteries have received widespread attention as a power source for devices such as electric bicycles, electric cars, and hybrid vehicles, as well as for mobile devices such as mobile phones, digital cameras, and laptops.

[0006] Generally, lithium secondary batteries can be classified based on the shape of their external materials into can-type secondary batteries with electrode components built into a metal can and bag-type secondary batteries with electrode components built into an aluminum laminate.

[0007] For small mobile devices, each device uses one or three battery cells, while medium or large devices such as vehicles require high power and large capacity. Therefore, medium or large battery modules with multiple battery cells electrically connected to each other are used. In such battery modules, a large number of battery cells are connected in series or parallel to form a battery cell stack, thereby increasing capacity and output. Furthermore, one or more battery modules can be integrated with various control and protection systems such as a battery management system (BMS) and a cooling system to form a battery pack.

[0008] Because the battery cells that make up these medium or large battery modules include rechargeable / dischargeable secondary batteries, these high-output and high-capacity secondary batteries generate a significant amount of heat during charging and discharging. In particular, because the laminates of pouch cells, which are widely used in battery packs, are coated with polymer materials with low thermal conductivity, it is difficult to effectively reduce the temperature of the entire battery cell.

[0009] When the heat generated during charging and discharging is not effectively dissipated, heat buildup occurs, which accelerates the degradation of individual battery cells. Depending on the circumstances, the battery module may catch fire or explode. Therefore, a cooling system is crucial for cooling the individual battery cells in high-output, high-capacity battery modules and / or battery packs. Summary of the Invention

[0010] Technical issues

[0011] The purpose of this disclosure is to provide a battery module with improved cooling performance and a battery pack including the battery module.

[0012] However, the technical problems to be solved by the embodiments of this disclosure are not limited to the above-described problems, and various extensions can be made within the scope of the technical ideas included in this disclosure.

[0013] Technical solution

[0014] According to one embodiment of the present disclosure, a battery module is provided, including: a battery cell stack formed by stacking a plurality of battery cells; a module frame for accommodating the battery cell stack; and a thermal pad located between the upper surface of the module frame and the battery cell stack, wherein the thermal pad has a recessed pattern on its surface facing the battery cell stack that corresponds to a first end of a battery cell.

[0015] The first end of a battery cell can have a double-folded shape.

[0016] The battery cell includes a cell housing and an electrode assembly housed in the cell housing, and the double-folded shape can be the shape of a double-folded seal formed by folding the sealing portion of the cell housing at least twice.

[0017] The battery also includes electrode leads that protrude from at least one of the two ends of the battery cell in a direction perpendicular to a first end of the battery cell, wherein the battery cell may have a rectangular structure that is longer in the direction in which the electrode leads protrude.

[0018] The recessed pattern of the thermal pad may include multiple recesses corresponding to the double-folded seal of each of the multiple battery cells.

[0019] The first end of the battery cell may have two different inclined surfaces, the recess may be formed to correspond to one of the two inclined surfaces, and the double-folded sealing part may be in close contact with the recess.

[0020] The inclined surface of the first end and the inclined surface of the heat-conducting pad on which a recess can be formed are in contact with each other.

[0021] The thermal pad has a first surface facing the upper surface of the module frame and a second surface facing the battery cell stack, and the first and second surfaces may have asymmetrical structures.

[0022] The first surface of the thermal pad may have a surface parallel to the upper surface of the module frame.

[0023] The recessed pattern can have a serrated shape.

[0024] The battery module may also include a thermally conductive resin layer located between the lower surface of the module frame and the battery cell stack.

[0025] The module frame includes: a frame member having a bottom and two side portions facing each other; and a top plate covering the open upper portion of the frame member, and a thermally conductive resin layer may be located between the bottom of the frame member and the battery cell stack.

[0026] The bottom and side sections included in the frame components can be integrally formed.

[0027] The battery may also include a thermally conductive resin component located between the recessed pattern of the thermal pad and the first end of the battery cell.

[0028] According to another embodiment of this disclosure, a battery pack including the above-described battery module is provided.

[0029] Beneficial effects

[0030] According to embodiments of this disclosure, an additional heat transfer component is formed between the upper surface of the module frame and the battery cell stack, thereby improving the thermal conductivity for dissipating heat generated by the battery cells and improving the cooling performance of the battery module and battery pack. Attached Figure Description

[0031] Figure 1 This is an exploded perspective view showing a battery module according to an embodiment of the present disclosure.

[0032] Figure 2 It is shown Figure 1 A perspective view of the battery module components in a coupled state.

[0033] Figure 3 It is shown Figure 1 A perspective view of a single battery cell included in a battery cell stack.

[0034] Figure 4 It is along Figure 2 A cross-sectional view taken from the yz plane.

[0035] Figure 5 It is shown Figure 4 A magnified perspective view of part A.

[0036] Figure 6 This is a diagram illustrating the structure of the thermal pad according to this embodiment.

[0037] Figure 7 It shows that it is equipped with Figure 6 A diagram of a battery module with a thermal pad.

[0038] Figure 8 This is a graph showing the temperature change over time in the case of a central battery cell.

[0039] Figure 9 It is a graph showing the temperature change over time in the case of edge monomers.

[0040] Figure 10 and Figure 11 This is a diagram illustrating a battery module according to another embodiment of the present disclosure.

[0041] Figure 12 It is shown Figure 10 A diagram showing a variation of the filling method for thermally conductive resin. Detailed Implementation

[0042] In the following, various embodiments of the present disclosure will be described in detail with reference to the accompanying drawings to enable those skilled in the art to readily implement these embodiments. The present disclosure can be modified in various different ways and is not limited to the embodiments set forth herein.

[0043] Parts irrelevant to the description will be omitted in order to clearly describe this disclosure, and the same reference numerals denote the same elements throughout the specification.

[0044] Furthermore, the dimensions and thicknesses of each element in the accompanying drawings are arbitrarily shown for ease of description, and this disclosure is not necessarily limited to the dimensions and thicknesses shown in the drawings. The thicknesses of layers, regions, etc., are exaggerated in the drawings for clarity. The thicknesses of some layers and regions are exaggerated in the drawings for ease of description.

[0045] Furthermore, it should be understood that when an element such as a layer, membrane, region, or plate is referred to as being "on" or "above" another element, it can be directly on the other element, or there may be intermediate elements present. Conversely, when an element is referred to as being "directly on" another element, it means that there are no other intermediate elements present. Additionally, the terms "on" or "above" refer to being positioned above or below a reference point, and do not necessarily refer to being positioned at the upper end of the reference point in the direction opposite to gravity.

[0046] Furthermore, throughout the specification, when a section is referred to as "including" a component, it means that the section may also include other components, without excluding other components, unless otherwise stated.

[0047] Furthermore, throughout the instruction manual, when referred to as a "plane," it means when the target portion is viewed from above; when referred to as a "section," it means when the target portion is viewed from the side of a vertically cut section.

[0048] Figure 1 This is an exploded perspective view showing a battery module according to an embodiment of the present disclosure. Figure 2 It is shown Figure 1 A perspective view of the battery module components in a coupled state. Figure 3 It is shown Figure 1 A perspective view of a single battery cell included in a battery cell stack.

[0049] Reference Figure 1 and Figure 2 A battery module 100 according to one embodiment of the present disclosure includes: a battery cell stack 120 comprising a plurality of battery cells 110; a module frame 500 for housing the battery cell stack 120; and an end plate 150 for covering the front and rear surfaces of the module frame 500. The module frame 500 may include: a frame member 300, the upper surface, front surface, and rear surface of which are open; and an upper plate 400 covering the upper portion of the battery cell stack 120. The frame member 300 may be U-shaped. The battery module 100 also includes a busbar frame 130 located between the battery cell stack 120 and the end plate 150. The end plate 150 may be formed of a metallic material such as aluminum. The end plate 150 may include a front panel for covering one side of the module frame 500 and a rear panel for covering the other side of the module frame 500.

[0050] When the open sides of the frame member 300 are referred to as the first side and the second side, respectively, the frame member 300 has a plate-like structure that is bent to continuously surround the front, lower, and rear surfaces of the remaining outer surfaces of the battery cell stack 120, excluding the surfaces corresponding to the first and second sides. The upper surface corresponding to the lower surface of the frame member 300 is open. Specifically, the frame member 300 may include a bottom and two side faces facing each other. In this case, the bottom and the two side faces may be integrally formed.

[0051] The upper plate 400 has a single plate-like structure that surrounds the remaining upper surface except for the front, lower, and rear surfaces surrounded by the frame member 300. The frame member 300 and the upper plate 400 can be coupled together by welding or the like, with their respective corner regions in contact with each other, thereby forming a structure surrounding the battery cell stack 120. That is, the frame member 300 and the upper plate 400 can have coupling portions CP formed at their respective corner regions by coupling methods such as welding, thereby forming a module frame 500.

[0052] The battery module 100 according to this disclosure includes a thermally conductive resin layer 310 located between a module frame 300 and a battery cell stack 120, and a thermally conductive pad 330 located between an upper surface 400 and the battery cell stack 120. The conductive pad 330 may be formed of a silicon-based material similar to the thermally conductive resin layer 310 and may be used as a compression pad.

[0053] The battery cell stack 120 includes multiple battery cells 110 stacked along one direction, and the multiple battery cells 110 can be stacked along the Y-axis direction, such as... Figure 1 As shown. The battery cell 110 is preferably a pouch cell. For example, see reference... Figure 3 According to this embodiment, the battery cell 110 may have a structure in which two electrode leads 111 and 112 protrude from one end 114a and the other end 114b of the battery body 113 in opposite directions. The battery cell 110 can be manufactured by joining the two ends 114a and 114b of the cell housing 114 and the two sides 114c connecting them while the electrode assembly (not shown) is housed within the cell housing 114. In other words, the battery cell 110 according to this embodiment has a total of three sealing portions 114sa, 114sb, and 114sc, and the sealing portions 114sa, 114sb, and 114sc have a structure that is sealed by a method such as thermal fusion, and the remaining sides may be formed by connecting portions 115. The space between the two ends 114a and 114b of the single-cell housing 114 is defined as the longitudinal direction of the battery cell 110, and the space between a side 114c and the connecting portion 115 that connects the two ends 114a and 114b of the single-cell housing 114 is defined as the width direction of the battery cell 110.

[0054] The connecting portion 115 is a long region extending along one edge of the battery cell 110, and a protrusion 110p of the battery cell 110 may be formed at the end of the connecting portion 115. The protrusion 110p may be formed on at least one of the two ends of the connecting portion 115 and may protrude in a direction perpendicular to the direction in which the connecting portion 115 extends. The protrusion 110p may be located between one of the sealing portions 114sa and 114sb of the two ends 114a and 114b of the cell housing 114 and the connecting portion 115.

[0055] The cell housing 114 is typically formed of a laminated structure of resin layer / metal film layer / resin layer. For example, when multiple cell housings are stacked to form a medium or large battery module, the surface of the cell housing formed by the O (oriented)-nylon layer is prone to slippage due to external impact. Therefore, to prevent such slippage and maintain a stable stacked structure of the cell housings, the cell stack 120 can be formed by attaching an adhesive member (e.g., an adhesive such as double-sided tape or a chemical adhesive that is chemically coupled during adhesion) to the surface of the cell housing. In this embodiment, the cell stack 120 is stacked in the Y-axis direction and housed in the frame member 300 in the Z-axis direction, and can then be cooled by the thermally conductive resin layer described later. As a comparative example, there are cases where the cell housings are formed as box-shaped components to fix the cell housings together by assembling a battery module frame. In this comparative example, due to the presence of the box-shaped components, the cooling effect may be minimal or occur in the surface direction of the cell housings, thus cooling cannot proceed well in the height direction of the battery module.

[0056] According to this embodiment, the widths of the side portion 300b of the U-shaped frame 300 and the upper plate 400 can be the same. In other words, the corners of the upper plate 400 along the X-axis and the corners of the side portion 300b of the frame member 300 along the X-axis can meet each other to be coupled by a method such as welding.

[0057] Figure 4 It is along Figure 2 A cross-sectional view taken from the yz plane.

[0058] Reference Figure 2 and Figure 4 According to this embodiment, the battery module 100 may include a heat transfer medium layer 820 located below the bottom 300a of the module frame 500. The heat transfer medium layer 820 may be formed of a heat transfer material that allows heat to be transferred to the module frame 500 and then to the heat sink 830 described later.

[0059] The battery module 100 according to this embodiment may further include a heat sink 830 located below the heat transfer medium layer 820. The heat sink 830 includes a refrigerant flow path formed therein and can perform the function of dissipating heat generated in the battery cell stack 120 to the outside. However, improving the thermal efficiency of the heat sink 830 solely by using the heat transfer medium layer 820 and / or the thermally conductive resin layer 310 has limitations in meeting the cooling performance level required by the user.

[0060] It is necessary to reduce the maximum temperature caused by the heat generated by individual battery cells in the battery module and to reduce temperature deviations caused by the position of the battery cells, thereby improving cooling performance. However, adding a cooling device results in an increase in the size of the battery module. To improve this problem, according to this embodiment, a thermally conductive pad 330 is formed in the air space between the upper plate 400 and the battery cell stack 120 without a heat sink 830, thereby improving cooling performance while maintaining a compact module structure.

[0061] Figure 5 It is shown Figure 4 A magnified perspective view of part A.

[0062] Based on the comparison examples, such as Figure 5 As shown, an air gap exists between the upper plate 400 and the battery cell stack 120. This air gap degrades heat conduction characteristics and hinders the transfer of heat from the upper part of the battery cell 110 (particularly the portion of the battery cell 110 adjacent to the double-sided folded seal DSF) to... Figure 4 The 830 radiator, when cooled, must pass through multiple layers, thus reducing its cooling efficiency.

[0063] Figure 6 This is a diagram illustrating the structure of the thermal pad according to this embodiment. Figure 7 It shows that it is equipped with Figure 6 A diagram of a battery module with a thermal pad.

[0064] Reference Figure 6 and Figure 7 According to this embodiment, the thermal pad 330 is located between the upper plate 400 corresponding to the upper surface of the module frame and the battery cell stack 120. The thermal pad 330 has a first surface facing the upper surface of the module frame and a second surface facing the battery cell stack, and the first and second surfaces have asymmetrical structures. The first surface may have a surface parallel to the upper plate 400 corresponding to the upper surface of the module frame.

[0065] The thermal pad 330 has a recessed pattern 330DP formed on the surface facing the battery cell stack 120. The recessed pattern 330DP may have a serrated shape. The recessed pattern 330DP has a structure corresponding to the first end of the battery cell 110, and the first end of the battery cell 110 may have a double-folded shape. The double-folded shape is the shape of a double-folded seal (DSF) formed by folding the sealing portion of the cell housing at least twice. Specifically, as... Figure 3 As shown, the first end of the battery cell 110 may be a portion 114sc to which the two sides 114c of the cell housing 114, which connect the two ends 114a and 114b, are adhered, is attached. Figure 3In this configuration, electrode leads 111 and 112 may be located at both ends of the battery cell 110 arranged in a direction perpendicular to the first end of the battery cell 110, and the battery cell 110 may have a rectangular structure, wherein the electrode leads 111 and 112 are formed to be longer in the protruding direction.

[0066] Reference Figure 6 and Figure 7 According to this embodiment, the recessed pattern 330DP of the thermal pad 330 includes a plurality of recesses 331DP corresponding to the double-sided folded seal portion DSF of each of the plurality of battery cells 110.

[0067] The first end of the battery cell 110 has two different inclined surfaces, and the thermal pad 330 also has a corresponding first inclined surface SP1 and a second inclined surface SP2. The first inclined surface SP1 of the thermal pad 330 can contact the first end of the battery cell 110, and the second inclined surface SP2 of the thermal pad 330 can contact the inclined surface of the double-sided folded seal portion DSF. To form such a structure, the double-sided folded seal portion DSF can be in close contact with the recessed portion 331DP of the thermal pad 330. By realizing such a structure, the contact area between the battery cell stack 120 and the thermal pad 330 can be maximized, and the cooling performance can be improved.

[0068] Due to the double-sided folded sealing element (DSF) structure, an air gap is formed between the battery cell 110 and the DSF. Therefore, compared to the portion where the first inclined surface SP1 of the thermal pad 330 contacts the first end of the battery cell 110, the portion where the second inclined surface SP2 of the thermal pad 330 contacts the inclined surface of the DSF has a weaker adhesive force. Therefore, as... Figure 7 As shown, the heat moving in the direction of the arrow passing through the second inclined surface SP2 is relatively smaller compared to the heat moving in the direction of the arrow passing through the first inclined surface SP1. Specifically, since the double-sided folded seal (DSF) is folded twice to complete the seal, the thermal efficiency of the mold sealing gap present therein can be supplemented by the thermally conductive pad 330.

[0069] Figure 8 This is a graph showing the temperature change over time in the case of a central battery cell. Figure 9 It is a graph showing the temperature change over time in the case of edge monomers.

[0070] Table 1 below summarizes Figure 8 and 9 The results of the maximum, minimum, and temperature difference values ​​are shown.

[0071] [Table 1]

[0072]

[0073] Reference Figure 8 ,like Figure 5 As shown, in the comparative example, there is an air gap between the upper plate 400 and the battery cell stack 120. At this time, when the battery cells are charged and discharged (under conditions where charging rate is higher than 1C and discharging rate is lower than 1C), the temperature rises rapidly in the initial stage due to the generated heat, and then converges to a constant temperature after approximately 1000 seconds or more. (Refer to...) Figure 9 In the embodiments disclosed herein, a thermal pad 330 exists between the upper plate 400 and the battery cell stack 120, as shown in the figure. At this time, when the battery cell is charging and discharging, the temperature rises rapidly in the initial stage due to the heat generated, and after about 1100 seconds or longer, it converges to a constant temperature or the temperature drops slightly.

[0074] Referring to Table 1 above, in the comparative example, the temperature difference between the highest temperature of the central battery cell and the lowest temperature of the edge battery cells was 10.2 degrees Celsius, while in this embodiment, the temperature difference between the highest temperature of the central battery cell and the lowest temperature of the edge battery cells was 8.5 degrees Celsius. In summary, it can be confirmed that the temperature difference in this embodiment is reduced by approximately 16% compared to the comparative example.

[0075] Figure 10 and Figure 11 This is a diagram illustrating a battery module according to another embodiment of the present disclosure.

[0076] The battery module according to this embodiment also includes a thermally conductive resin component 320, which is located between the thermally conductive pad 330 and one end of the battery cell 110 that has a double-sided folded sealing portion DSF. Figure 11 As shown. Figure 10 As shown, the thermally conductive resin component 320 can be formed by filling the recessed pattern 330DP of the thermally conductive pad 330 with thermally conductive resin 320p, and then pressing the thermally conductive pad 330 and the battery cell stack 120 together. Preferably, the thermally conductive pad 330 and the battery cell stack 120 are pressed before the thermally conductive resin 320p cures. To fill the recessed pattern 330DP of the thermally conductive resin 320p into the thermally conductive pad 330, the thermally conductive resin 320p can be filled along the direction of gravity while the thermally conductive pad 330 is flipped over. Figure 10 The results are different.

[0077] Figure 12 It is shown Figure 10 A diagram showing a variation of the filling method for thermally conductive resin.

[0078] Reference Figure 12 ,and Figure 10As described in the text, thermally conductive resin 420p can be coated onto the ends of the battery cell stack 120. Subsequently, a thermally conductive pad 330 can be pressed onto the battery cell stack 120 coated with thermally conductive resin 420p to form a thermally conductive resin component 320, as shown. Figure 11 As shown. According to Figures 10 to 12 The embodiments described herein further minimize the air gap through the thermally conductive resin component 320, thus being more advantageous in terms of thermal efficiency compared to the case where thermal efficiency is supplemented only by the thermally conductive pad 330.

[0079] On the other hand, one or more of the battery modules according to this embodiment can be encapsulated in a battery pack housing to form a battery pack.

[0080] The aforementioned battery module and battery pack including the battery module can be applied to various devices. Such devices can be applied to vehicle devices, such as electric bicycles, electric vehicles, or hybrid vehicles, but this disclosure is not limited thereto, and can also be applied to various devices within the scope of this disclosure that can use the battery module.

[0081] Although the invention has been illustrated and described above with reference to preferred embodiments, the scope of this disclosure is not limited thereto, and those skilled in the art can devise many other modifications and embodiments that fall within the spirit and scope of the principles of the invention described in the appended claims.

[0082] [Explanation of Labels in the Attached Image]

[0083] 100: Battery module; 120: Battery cell stack

[0084] 310: Thermally conductive resin layer; 320: Thermally conductive resin component

[0085] 330: Thermal pad; 330DP: Recessed pattern

[0086] 331DP: Recessed portion 400: Upper plate

[0087] 500: Module frame; 830: Heat sink

[0088] DSF: Double-sided folded seal

Claims

1. A battery module, comprising: A battery cell stack is formed by stacking multiple battery cells. A modular framework for accommodating the battery cell stack; as well as A thermal pad is located between the upper surface of the module frame and the battery cell stack. The thermal pad has a recessed pattern on its surface facing the battery cell stack, the shape of which corresponds to the shape of the first end of the battery cell. The thermally conductive pad is used as a compression pad, and The first end of the battery cell extends along the longitudinal direction of the battery cell and forms a double-folded sealing portion. A thermally conductive resin member is disposed between the recessed pattern and the first end of the battery cell to minimize the air gap between the recessed pattern and the double-folded sealing portion. The first end of the battery cell has two different inclined surfaces, and the recessed pattern has a first inclined surface and a second inclined surface that correspond to and contact the two inclined surfaces. Among them, the inclined surface that contacts the second inclined surface of the two inclined surfaces at the first end is the inclined surface of the double-folded sealing part.

2. The battery module according to claim 1, wherein, The battery cell includes a cell casing and an electrode assembly housed within the cell casing, and The double-fold seal is formed by folding the seal of the monolithic housing at least twice.

3. The battery module according to claim 2, The battery module further includes electrode leads that protrude from at least one of two ends of the battery cell, which are disposed in a direction perpendicular to the first end of the battery cell. in, The battery cell has a relatively long rectangular structure formed along the direction in which the electrode leads protrude.

4. The battery module according to claim 2, wherein, The recessed pattern of the thermal pad includes a plurality of recesses corresponding to the double-folded seal of each of the plurality of battery cells.

5. The battery module according to claim 4, wherein, The recess is formed to correspond to one of the two inclined surfaces, and the double-folded sealing portion is in close contact with the recess.

6. The battery module according to claim 1, wherein, The thermal pad has a first surface facing the upper surface of the module frame and a second surface facing the battery cell stack, and the first surface and the second surface have asymmetrical structures.

7. The battery module according to claim 6, wherein, The first surface of the thermal pad has a surface parallel to the upper surface of the module frame.

8. The battery module according to claim 1, wherein, The recessed pattern has a serrated shape.

9. The battery module according to claim 1, The battery module also includes a thermally conductive resin layer located between the lower surface of the module frame and the battery cell stack.

10. The battery module according to claim 9, wherein, The module frame includes a frame member and a top plate. The frame member includes a bottom and two side portions facing each other. The top plate covers the open upper portion of the frame member. The thermally conductive resin layer is located between the bottom of the frame member and the battery cell stack.

11. The battery module according to claim 10, wherein, The bottom and side portions of the frame member are integrally formed.

12. A battery pack comprising the battery module according to claim 1.

Images