Battery module and battery pack including same

Abstract

A battery module according to one embodiment of the present invention includes a battery cell stack including a plurality of battery cells, and a module frame accommodating the battery cell stack. The battery cells include an electrode assembly and a battery case having open front and rear surfaces accommodating the electrode assembly, and sealing portions are formed on the front and rear surfaces of the battery case, respectively.

Description

[Technical Field]

[0001] Cross-citation with related applications (etc.) This application claims the benefit of priority based on Korean Patent Application No. 10-2022-0007953, dated January 19, 2022, and all contents disclosed in the documents of that Korean patent application are incorporated herein by reference.

[0002] The present invention relates to a battery module and a battery pack including the same, and more particularly to a battery module and a battery pack with improved cooling performance. [Background technology]

[0003] Due to technological developments and increasing demand for mobile devices, the demand for secondary batteries as an energy source is rapidly increasing. In particular, secondary batteries are attracting attention as an energy source not only for mobile devices such as mobile phones, digital cameras, laptops, and wearable devices, but also for power devices such as electric bicycles, electric vehicles, and hybrid electric vehicles.

[0004] While small mobile devices use one or two to four battery cells per device, medium to large devices such as automobiles require high output and large capacity. Therefore, medium to large battery modules, which electrically connect many battery cells, are used.

[0005] Since it is preferable to manufacture medium- to large-sized battery modules with as small a size and weight as possible, prismatic and pouch-shaped batteries, which can be stacked with a high degree of integration and have a low weight relative to their capacity, are commonly used as battery cells for medium- to large-sized battery modules. To achieve high output, these battery modules have a structure in which multiple cell assemblies, each including a plurality of unit battery cells, are connected in series. The battery cells are capable of repeated charging and discharging through electrochemical reactions between components, such as positive and negative electrode current collectors, separators, active materials, and electrolytes.

[0006] Meanwhile, in recent years, as the need for large capacity structures, including use as an energy storage source, has increased, there has been an increasing demand for a number of battery modules in which a number of secondary batteries are connected in series and / or parallel, and for multi-module battery packs in which the battery modules are assembled.

[0007] In addition, when a battery pack is constructed by connecting a plurality of battery cells in series / parallel, a common method is to first construct a battery module consisting of at least one battery cell, and then use this at least one battery module to add other components to construct the battery pack.

[0008] Generally, if a secondary battery is heated above its optimum temperature, its performance may deteriorate, and in severe cases, it may explode or catch fire. In particular, in a battery module or battery pack including multiple secondary batteries, i.e., battery cells, the heat generated by the multiple battery cells may be added together in a small space, causing the temperature to rise more rapidly and excessively. In other words, a battery module with multiple stacked battery cells and a battery pack equipped with such a battery module can produce high output, but it is difficult to remove the heat generated by the battery cells during charging and discharging. If the battery cells do not properly dissipate heat, the battery cells will deteriorate more quickly, their lifespan will be shortened, and the risk of explosion or fire will increase.

[0009] Furthermore, battery modules included in vehicle battery packs are often exposed to direct sunlight and may be placed in high temperature conditions such as in summer or desert regions.

[0010] Fig. 1 is a perspective view of a conventional battery module. Fig. 2 is a cross-sectional view taken along the line A-A' in Fig. 1. Fig. 3 is an enlarged view of part B in Fig. 2.

[0011] 1 to 3, a conventional battery module 10 includes a battery cell stack 12 in which a plurality of battery cells 11 are stacked in one direction, a module frame 25 that houses the battery cell stack 12, and end plates 15 that cover the front and rear surfaces of the battery cell stack 12. The module frame 25 includes a lower frame 30 that covers the bottom and both side surfaces of the battery cell stack 12, and an upper plate 40 that covers the top surface of the battery cell stack 12. Furthermore, a thermally conductive resin layer 31 may be formed between the bottom of the battery cell stack 12 and the bottom of the module frame 25.

[0012] 3, the battery cells 11 of the conventional battery module 10 are configured with the sealing portion 11a either folded or left as is. When the sealing portion 11a is arranged as shown in FIG. 3, it is difficult to utilize the space between the upper plate 40 and the battery cell stack 12 due to the sealing portion 11a. Therefore, due to the arrangement of the sealing portion 11a, not only is it difficult to achieve an effective cooling effect through the top of the battery module 10, but there is also the problem that cooling performance is reduced due to an air layer formed adjacent to the sealing portion 11a, such as in the space between the sealing portion 11a and the body of the battery cell 11.

[0013] Therefore, a new structure is needed to solve the heat generation problem of battery cells that arises when high capacity, high energy, and rapid charging are required. Summary of the Invention [Problem to be solved by the invention]

[0014] An object of the present invention is to provide a battery module with improved cooling performance and a battery pack including the same.

[0015] However, the problems that the present invention aims to solve are not limited to the problems mentioned above, and problems not mentioned will be clearly understood by those having ordinary skill in the art to which the present invention pertains from this specification and the accompanying drawings. [Means for solving the problem]

[0016] A battery module according to one embodiment of the present invention includes a battery cell stack including a plurality of battery cells, and a module frame that houses the battery cell stack. The battery cells include an electrode assembly and a battery case that houses the electrode assembly and has open front and rear surfaces, and sealing portions are formed on the front and rear surfaces of the battery case.

[0017] The battery case may be a tubular case with an open front and rear.

[0018] The battery cell stack may further include a thermally conductive resin layer positioned between an upper portion of the battery cell stack and the module frame, and the upper portion of the battery cell stack in contact with the thermally conductive resin layer may have a flat shape.

[0019] The battery cell may be sealed by the two sealing portions.

[0020] The battery cell may further include an electrode lead protruding from the battery cell, and the sealing portion may be formed adjacent to the electrode lead.

[0021] A battery module according to another embodiment of the present invention may further include a sealing portion formed on one side of the battery cell, and the sealing portion formed on the one side may be formed to protrude from the battery case.

[0022] The sealing portion formed on the one side may be formed to protrude from the closed surface of the battery case.

[0023] The one side of the battery cell may be one side of an upper portion of the battery case.

[0024] The sealing portion formed on the one side may be formed on an edge of the one side.

[0025] The protruding sealing portion may be curved and bonded from an edge of the one side toward a center of the one side.

[0026] The sealing portion formed on the one side may be formed at the center of the one side.

[0027] The protruding sealing portion may be curved from the center of the one side toward the edge of the one side and adhered.

[0028] A battery pack according to yet another embodiment of the present invention includes the battery module. [Effects of the Invention]

[0029] The battery module according to an embodiment of the present invention includes battery cells with minimized sealing portions, thereby effectively cooling the battery cells that may become hot in high current and fast charging environments, and also minimizing the internal temperature deviation of the battery module, thereby improving the stability of the battery module.

[0030] The effects of the present invention are not limited to the effects described above, and effects not mentioned will be clearly understood by those having ordinary skill in the art to which the present invention pertains from this specification and the accompanying drawings. [Brief explanation of the drawings]

[0031] [Figure 1] FIG. 1 is a perspective view of a conventional battery module. [Figure 2] FIG. 2 is a cross-sectional view taken along the line AA' in FIG. [Figure 3] FIG. 3 is an enlarged view of part B in FIG. [Figure 4] FIG. 4 is an exploded perspective view of a battery module according to an embodiment of the present invention. [Figure 5]FIG. 5 is a cross-sectional view of a battery module according to an embodiment of the present invention taken along the line AA' in FIG. [Figure 6] FIG. 6 is an enlarged view of part C in FIG. [Figure 7] FIG. 7 is a perspective view showing a battery cell included in a battery module according to an embodiment of the present invention. [Figure 8] FIG. 8 is a perspective view showing a battery case included in the battery cell of FIG. [Figure 9] FIG. 9 is a cross-sectional view taken along the line DD' in FIG. [Figure 10] FIG. 10 is a diagram showing a battery cell included in a battery module according to another embodiment of the present invention. [Figure 11] FIG. 11 is a diagram showing both the battery cell of FIG. 10 and a sealing portion formed on the battery cell of FIG. [Figure 12] FIG. 12 is a view showing another type of sealing portion formed on the battery cell of FIG. DETAILED DESCRIPTION OF THE INVENTION

[0032] While the present invention may be embodied in many different forms, it is to be understood that the invention is not limited to the embodiments set forth herein.

[0033] In order to clearly describe the present invention, parts that are not relevant to the description will be omitted, and the same reference numerals will be used throughout the specification to refer to the same or similar components.

[0034] Furthermore, the size and thickness of each component shown in the drawings are arbitrarily shown for the convenience of explanation, and the present invention is not necessarily limited to those shown in the drawings. Thicknesses are exaggerated in the drawings to clearly show various layers and regions. In the drawings, the thicknesses of some layers and regions are exaggerated for the convenience of explanation.

[0035] Furthermore, when a layer, film, region, plate, or other part is said to be "on" or "above" another part, this includes not only the case where it is "directly above" that other part, but also the case where there is another part in between. Conversely, when a part is said to be "directly above" another part, it means that there is no other part in between. Furthermore, being "on" or "above" a reference part means being located above or below the reference part, and does not necessarily mean being located "on" or "above" in the opposite direction of gravity.

[0036] Furthermore, throughout the specification, when a part "comprises" a certain element, this does not mean that other elements are excluded, and that other elements may also be included, unless otherwise specified to the contrary.

[0037] Furthermore, throughout the specification, "on a plane" means when the subject part is viewed from above, and "on a cross section" means when the subject part is cut vertically and viewed from the side.

[0038] The terms "first" and "second" used in this application can be used to describe various components, but the components should not be limited by the terms. The terms are used only to distinguish one component from another.

[0039] The battery module of the present invention will be described below with reference to FIG.

[0040] FIG. 4 is an exploded perspective view of a battery module according to an embodiment of the present invention.

[0041] Referring to FIG. 4, a battery module 100 according to this embodiment includes a battery cell stack 120 in which a plurality of battery cells 110 are stacked, and a module frame 200 that houses the battery cell stack 120.

[0042] The module frame 200 includes a U-shaped frame 300 that is open at the top, front, and rear and covers the bottom and both sides of the battery cell stack 120, and an upper plate 400 that covers the top of the battery cell stack 120. In this case, the U-shaped frame 300 may include a bottom portion 300a that supports the bottom of the battery cell stack 120 and side portions 300b that extend upward from both ends of the bottom portion 300a. However, the module frame 200 is not limited to this and may be replaced with a frame of another shape, such as an L-shaped frame or a monoframe that surrounds the battery cell stack 120 except for the front and rear sides. The module frame 200 can physically protect the battery cell stack 120 housed therein.

[0043] The top plate 400 can cover the open upper side of the module frame 200. The end plates 150 can cover the front and rear sides of the battery cell stack 120 that are open on the module frame 200. The end plates 150 can be joined to the front and rear corners of the top plate 400 and the front and rear corners of the module frame 200 by welding them to each other.

[0044] A bus bar frame 130 may be formed between the end plate 150 and the front and rear surfaces of the battery cell stack 120. The bus bar frame 130 may cover the portion of the battery cell stack 120 exposed from the module frame 200. In addition, a plurality of bus bars 160 attached to the bus bar frame 130 may be formed to protrude from the battery cells 110 and connected to the electrode leads 111, 112, etc. attached to the bus bar frame 130. In this case, slots through which the electrode leads 111, 112 pass may be formed in the bus bar 160. Therefore, the electrode leads 111, 112 passing through the slots of the bus bar 160 may come into contact with the bus bar 160.

[0045] In addition, the battery module 100 according to this embodiment further includes a first thermally conductive resin layer 310 located between the underside of the battery cell stack 120 and the bottom of the module frame 200, i.e., the bottom 300a of the U-shaped frame 300. The first thermally conductive resin layer 310 can transfer heat generated in the battery cells 110 to the bottom of the battery module 100 and serve to fix the battery cell stack 120.

[0046] Furthermore, the battery module 100 according to this embodiment may further include a second thermally conductive resin layer 320 formed between the upper portion of the battery cell stack 120 and the upper portion of the module frame 200, i.e., the upper plate 400. Therefore, heat generated in the battery cells 110 can also be transferred through the upper portion of the module frame 200 via the second thermally conductive resin layer 320.

[0047] In particular, the battery module 100 according to this embodiment can improve cooling performance by providing a heat transfer path to the top of the module frame 200 through the second thermally conductive resin layer 320, rather than a unidirectional path through the bottom of the module frame 200. In this case, the first thermally conductive resin layer 310 and the second thermally conductive resin layer 320 may be formed by applying and curing a thermally conductive resin. Therefore, although the first thermally conductive resin layer 310 and the second thermally conductive resin layer 320 are illustrated as plate-shaped, they can be freely deformed according to the shapes of the other components during the process of applying and curing the thermally conductive resin.

[0048] In conventional battery modules, heat generated in the battery cells is dissipated through a thermally conductive resin layer formed under the battery cells. However, this cooling structure, which only provides a one-way path through the thermally conductive resin layer formed under the battery cell stack and the bottom of the module frame, has the problem of being unable to efficiently dissipate the heat generated in the battery cells.

[0049] 1 to 3, however, the battery cells 11 of the conventional battery module have a sealing portion 11a, and there is a problem in that cooling performance is reduced due to an air layer formed adjacent to the sealing portion 11a, such as the space between the sealing portion 11a and the body of the battery cell 11. In addition, there is a problem in that the space occupied by the sealing portion 11a is relatively large, which reduces space efficiency.

[0050] Therefore, in situations where the battery cells generate a large amount of heat in a short time due to a high current flow, such as during rapid charging, a structure capable of effectively cooling the heat is required.

[0051] The battery cells 110 included in the battery module 100 according to this embodiment will be described in more detail below with reference to FIGS.

[0052] Fig. 5 is a cross-sectional view of a battery module according to an embodiment of the present invention taken along section line A-A' in Fig. 2. Fig. 6 is an enlarged view of part C in Fig. 5. Fig. 7 is a perspective view of a battery cell included in a battery module according to an embodiment of the present invention. Fig. 8 is a perspective view of a battery case included in the battery cell of Fig. 7. Fig. 9 is a cross-sectional view of a battery module taken along section line D-D' in Fig. 7.

[0053] 4 to 9, a battery cell 110 included in a battery module 100 according to this embodiment includes an electrode assembly 119 and a battery case 114 with an open front and rear that accommodates the electrode assembly 119, with sealing portions 114sa and 114sb formed on the front and rear surfaces, respectively, of the battery case 114. In this case, the electrode assembly 119 may include a positive electrode, a negative electrode, and a separator disposed between the positive and negative electrodes.

[0054] The battery cell 110 is preferably a pouch-type battery cell, and may be formed in a rectangular sheet-type structure. For example, referring to Fig. 7, the battery cell 110 according to this embodiment has a structure in which two electrode leads 111, 112 face each other and protrude from one end and the other end of a cell body 113, respectively. That is, the battery cell 110 includes the electrode leads 111, 112 protruding from the battery cell 110 in directions facing each other. More specifically, the electrode leads 111, 112 are connected to an electrode assembly 119 and protrude from the electrode assembly 119 to the outside of the battery cell 110.

[0055] The battery cell 110 may also include a battery case 114, which may have an open front and rear. Referring to Fig. 8, the battery case 114 may be a tubular case whose front and rear are open. Therefore, the electrode assembly 119 may be housed inside the battery case 114 through the front or rear of the battery case 114. The battery case 114 may also be made of a laminate sheet including a resin layer and a metal layer.

[0056] In this case, the battery case 114 may include both ends 114a, 114b and one side 114c connecting the both ends 114a, 114b. In this case, the one side 114c may be formed on either the upper or lower part of the battery case 114 in FIG. 8, but here, the one side 114c may refer to one side 114c of the upper part formed on the upper part. More specifically, the one side 114c may refer to the upper surface of the battery case 114. In addition, both ends 114a, 114b of the battery case 114 may be formed in an open shape, and therefore the battery case 114 may be a tubular case with open front and rear surfaces.

[0057] The battery cell 110 may be manufactured by bonding both ends 114a, 114b of the battery case 114 in a state where the electrode assembly 119 is housed in the battery case 114.

[0058] In other words, the battery cell 110 according to this embodiment has two sealing portions 114sa and 114sb formed by bonding both ends 114a and 114b of the battery case 114, and the sealing portions 114sa and 114sb may be sealed by a method such as heat fusion. Therefore, the battery cell 110 may be sealed by the two sealing portions 114sa and 114sb.

[0059] In addition, the front sealing portion 114sa and the rear sealing portion 114sb may be formed adjacent to the electrode leads 111 and 112, respectively. After the electrode leads 111 and 112 are formed to protrude from the battery cell 110, the sealing portions 114sa and 114sb may be formed to complete the sealing structure of the battery cell 110.

[0060] A plurality of such battery cells 110 may be configured, and the plurality of battery cells 110 may be stacked so as to be electrically connected to each other to form a battery cell stack 120. In particular, as shown in Fig. 4, the plurality of battery cells 110 may be stacked along a direction parallel to the y-axis. As a result, the electrode leads 111 and 112 may protrude in the x-axis direction and the -x-axis direction, respectively.

[0061] On the other hand, when the battery cells 110 are repeatedly charged and discharged, a large amount of heat may be generated, and a new structure for cooling the battery cells 110 may be required.

[0062] In this case, conventional battery modules have problems in that the cooling efficiency is reduced due to the space occupied by the sealing portion of the battery cell, and it is difficult to utilize the space when applying a thermally conductive resin layer on the upper surface.

[0063] Therefore, referring to Figures 5 and 6, the battery cell 110 according to this embodiment further includes a second thermally conductive resin layer 320 located between the top of the module frame 200 and the battery cell stack 120, and the top of the battery cell stack 120 in contact with the second thermally conductive resin layer 320 may have a flat shape.

[0064] 6, the top of the battery cell stack 120 may have a flat shape, and the flat shape may correspond to one side 114c of the battery cell 110. That is, the one side 114c of the battery cell 110 may be formed in a flat shape because it is an integral part of the tubular case and does not have a sealing portion.

[0065] As described above, the battery cells 110 of the battery module 100 according to this embodiment have sealing portions 114sa and 114sb formed only on the front and rear surfaces of the battery case 114, excluding one side portion 114c, thereby minimizing the space occupied by the sealing portions. In particular, minimizing the space occupied by the sealing portions minimizes heat transfer resistance and improves the cooling performance of the battery module.

[0066] Hereinafter, a battery cell included in a battery module according to another embodiment of the present invention will be described with reference to Figures 10 to 12. Since some of the content overlaps with the battery module and battery cell described above, only the content that is different will be described.

[0067] Fig. 10 is a view showing a battery cell included in a battery module according to another embodiment of the present invention. Fig. 11 is a view showing a sealing portion formed on the battery cell of Fig. 10. Fig. 12 is a view showing another type of sealing portion formed on the battery cell of Fig. 10.

[0068] 9 and 10 , the battery cell 110 may have spaces G1 and G2 formed between the battery case 114 and the electrode assembly 119. Referring to both FIGS. 9 and 10 , the battery cell 110 described above may also have the space G1 formed between the battery case 114 and the electrode assembly 119. However, in the battery cell 110 according to this embodiment, the space G2 between the battery case 114 and the electrode assembly 119 may be wider by a margin, taking into consideration the insertion of the electrode assembly 119. Therefore, in the battery cell 110 according to this embodiment, the space G2 between the battery case 114 and the electrode assembly 119, including the margin, is formed taking into consideration the insertion of the electrode assembly 119, thereby improving process efficiency and allowing the electrode assembly 119 to be easily inserted into the battery case 114.

[0069] In this case, after the electrode assembly 119 is inserted, the space G2 between the battery case 114 and the electrode assembly 119 is minimized to prevent the electrode assembly 119 from moving inside the battery cell 110, and sealing portions 114sc1 and 114sc2 may be formed on one side 114c of the battery case 114 to maximize the cooling surface.

[0070] In this case, the sealing portions 114sc1 and 114sc2 may be formed by crimping one side portion 114c of the battery case 114, or may be formed by heat sealing like the front sealing portion 114sa and the rear sealing portion 114sb.

[0071] Furthermore, the sealing portions 114sc1 and 114sc2 formed on one side 114c may be formed by protruding a portion of the tubular case. That is, instead of sealing an open area by gluing it like the front sealing portion 114sa and the rear sealing portion 114sb, the sealing portions may be formed by further protruding and crimping an already closed area so as to protrude from an unopened side of the battery case 114. Therefore, by forming a portion of the already closed battery case 114 into the sealing portions 114sc1 and 114sc2, the sealing portions 114sc1 and 114sc2 formed on one side 114c may also be used as gas storage spaces for the battery cell 110.

[0072] 11, the sealing portion 114sc1 formed on the one side 114c may be formed on the edge of the one side 114c. In this case, the sealing portion 114sc1 formed on the edge of the one side 114c may be formed to protrude from the one side 114c, and the protruding sealing portion 114sc1 may be formed to be curved and attached from the edge of the one side 114c toward the center of the one side 114c. Therefore, even if a space G2 is formed between the battery case 114 and the electrode assembly 119 to include a margin dimension, the electrode assembly 119 can be fixed after insertion, and the sealing portion 114sc1 is formed, minimizing the space it occupies, thereby maintaining and improving cooling performance.

[0073] 12, the sealing portion 114sc2 formed on one side 114c may be formed at the center of the one side 114c. In this case, the sealing portion 114sc2 formed at the center of the one side 114c may be formed to protrude from the one side 114c, or the protruding sealing portion 114sc2 may be formed to bend from the center of the one side 114c toward the edge of the one side 114c and be bonded. Therefore, the space occupied by the sealing portion 114sc1 is minimized, thereby maintaining and improving cooling performance.

[0074] As such, the battery cell 110 included in the battery module 100 of the present invention has a battery case 114 formed as a tubular case, and sealing portions are formed only on the front and rear surfaces, or even if a sealing portion is formed on one side 114c, the space occupied by the sealing portion can be minimized, thereby maximizing the cooling effect of the battery cell.

[0075] A battery pack according to still another embodiment of the present invention will now be described.

[0076] The battery pack according to the present embodiment includes the battery module described above. The battery pack according to the present invention may also be configured by assembling one or more battery modules according to the present embodiment and adding a battery management system (BMS) for managing the temperature and voltage of the battery, a cooling device, and the like.

[0077] The battery pack can be applied to various devices, including transportation means such as electric bicycles, electric cars, and hybrid cars, but the present invention is not limited thereto and can be applied to various devices using battery modules, which also fall within the scope of the present invention.

[0078] While preferred embodiments of the present invention have been illustrated and described above, the present invention is not limited to the specific embodiments described above, and it goes without saying that various modifications can be made by a person having ordinary knowledge in the technical field to which the invention pertains without departing from the gist of the present invention as claimed in the claims, and such modifications should not be understood separately from the technical ideas and perspectives of the present invention. [Explanation of symbols]

[0079] 100: Battery module 110: Battery cell 114sa, 114sb: Front and rear sealing parts 114sc1, 114sc2: Sealing part formed on one side 120: Battery cell stack 130: Bus bar frame 150: End plate 160: Busbar 200:Module frame 300: U-shaped frame 400: Upper plate

Claims

1. a battery cell stack including a plurality of battery cells; a module frame that houses the battery cell stack, The battery cell is an electrode assembly; a battery case having an open front and rear faces that accommodates the electrode assembly, a sealing portion is formed on each of the front and rear surfaces of the battery case; a thermally conductive resin layer positioned between an upper portion of the battery cell stack and the module frame, wherein the upper portions of all the battery cell stacks are in direct contact with the thermally conductive resin layer, and the upper portions of the battery cell stacks that are in contact with the thermally conductive resin layer have a flat shape.

2. The battery module according to claim 1 , wherein the battery case is a tubular case having an open front and rear faces.

3. The battery module according to claim 1 , wherein the battery cells are sealed by two of the sealing portions.

4. The battery cell further includes an electrode lead formed to protrude from the battery cell, etc. The battery module of claim 1 , wherein the sealing portion is formed adjacent to the electrode lead.

5. The battery cell further includes a sealing portion formed on one side thereof, The battery module of claim 1 , wherein the sealing portion formed on the one side protrudes from the battery case.

6. The battery module according to claim 5 , wherein the sealing portion formed on the one side protrudes from the unopened surface of the battery case.

7. The battery module according to claim 5 , wherein one side of the battery cell is one side of an upper portion of the battery case.

8. The battery module of claim 5 , wherein the sealing portion formed on the one side is formed on an edge of the one side.

9. The battery module of claim 8 , wherein the protruding sealing portion is bent from an edge of the one side toward a center of the one side and adhered.

10. The battery module of claim 5 , wherein the sealing portion formed on the one side is formed at a center of the one side.

11. The battery module of claim 10 , wherein the protruding sealing portion is bent from the center of the one side toward an edge of the one side and adhered.

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

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