Battery module and battery pack including same

Abstract

A battery module according to one embodiment of the present invention includes a battery cell stack in which a plurality of battery cells are stacked, a module frame surrounding the battery cell stack, a bus bar frame covering a portion of the battery cell stack exposed from the module frame, and a bus bar attached to the bus bar frame and connected to an electrode lead protruding from the battery cell stack, wherein a cooling flow path is formed in the bus bar.

Description

[Technical Field]

[0001] [Cross-reference to related applications] This application claims the benefit of priority based on Korean Patent Application No. 10-2021-0163388 dated November 24, 2021, 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 having a novel cooling structure. [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 much attention as an energy source for mobile devices such as mobile phones, digital cameras, laptops, and wearable devices, as well as 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, in which many battery cells are electrically connected, 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. Such battery modules have a structure in which a number of cell assemblies, each including a plurality of unit battery cells, are connected in series to achieve high output. The battery cells include positive and negative electrode current collectors, separators, active materials, and electrolytes, and can be repeatedly charged and discharged through electrochemical reactions between the components.

[0006] Meanwhile, as the need for large capacity structures increases, including the recent use of batteries as energy storage sources, there is 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 battery packs with a multi-module structure 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 a battery pack.

[0008] Generally, if a secondary battery's temperature rises above its normal range, its performance may deteriorate, and in severe cases, it may explode or burst. In particular, in battery modules or battery packs equipped with 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, battery modules with multiple stacked battery cells and battery packs equipped with such battery modules 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 bursting 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] In conventional battery modules, heat generated in the battery cells is dissipated only one way through a thermally conductive resin layer formed at the bottom of the battery cell stack and the bottom of the module frame. However, with the recent continuous increase in demand for high capacity, high energy, and fast charging, the amount of current flowing through the bus bars is increasing, and the heat generated in the bus bars, battery cells, and electrode leads is also increasing. This heat generation is difficult to effectively cool using conventional cooling structures alone.

[0011] Therefore, a new structure is needed to solve the busbar heating problem that occurs when high capacity, high energy, and rapid charging are required. Summary of the Invention [Problem to be solved by the invention]

[0012] An object of the present invention is to provide a battery module and a battery pack including the same that can reduce the temperature of battery cells and bus bars to improve cooling performance.

[0013] However, the problems that the present invention aims to solve are not limited to those mentioned above, and problems not mentioned will be clearly understood by a person having ordinary skill in the art to which the present invention pertains from this specification and the accompanying drawings. [Means for solving the problem]

[0014] A battery module according to one embodiment of the present invention includes a battery cell stack in which a plurality of battery cells are stacked, a module frame surrounding the battery cell stack, a bus bar frame covering a portion of the battery cell stack exposed from the module frame, and a bus bar attached to the bus bar frame and connected to an electrode lead protruding from the battery cell stack, wherein a cooling flow path is formed in the bus bar.

[0015] The cooling flow path may be formed inside the bus bar and serve as a passage through which a coolant flows.

[0016] The bus bar may have slots through which the electrode leads pass, and the cooling flow passage may include a first flow passage and a third flow passage formed perpendicular to the direction in which the slots are formed, and a second flow passage formed parallel to the direction in which the slots are formed.

[0017] The bus bar may be divided into two regions by the slot, and the first flow path and the third flow path may connect the two regions of the bus bar.

[0018] The first and third flow paths may be formed at an upper end and a lower end of the bus bar, respectively, and the second flow path may connect the first and third flow paths formed at the upper and lower ends of the bus bar, respectively.

[0019] The battery module according to this embodiment may further include a refrigerant inlet formed at one end of the bus bar and a refrigerant outlet formed at the other end of the bus bar.

[0020] The coolant inlet and the coolant outlet may be formed from a non-conductive material.

[0021] The refrigerant inlet may be formed at an upper end of the bus bar, and the refrigerant outlet may be formed at a lower end of the bus bar.

[0022] The coolant may include cooling water, and the cooling water may include insulating cooling water.

[0023] A battery pack according to another embodiment of the present invention may include the battery module. [Effects of the Invention]

[0024] A battery module according to an embodiment of the present invention includes a cooling channel formed inside a bus bar, thereby cooling the battery cells and bus bar, which may become hot in a high current and fast charging environment, and minimizing the internal temperature deviation of the battery module, thereby improving the stability of the battery module.

[0025] 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]

[0026] [Figure 1] FIG. 2 is an exploded perspective view of the battery module of the present invention. [Figure 2] FIG. 2 is a perspective view showing a battery module assembled from the components of FIG. 1. [Figure 3] 1 is a perspective view showing a bus bar included in a battery module according to an embodiment of the present invention; [Figure 4] 4 is a perspective view showing a cooling flow path formed in the bus bar of FIG. 3. [Figure 5] 4 is an enlarged view of a portion cut out along the P2 plane of FIG. 3. FIG. [Figure 6] FIG. 3 is a cross-sectional view taken along the P1 plane of FIG. 2. [Figure 7] FIG. 2 is a perspective view showing a battery cell included in the battery module of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0027] 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.

[0028] 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.

[0029] 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.

[0030] 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 direction opposite to gravity.

[0031] 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.

[0032] 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.

[0033] The terms "first" and "second" used in this application are 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.

[0034] The battery module of the present invention will be described below with reference to FIGS. 1, 2 and 7. FIG.

[0035] Fig. 1 is an exploded perspective view of a battery module of the present invention. Fig. 2 is a perspective view showing a battery module assembled from the components of Fig. 1. Fig. 7 is a perspective view showing a battery cell included in the battery module of the present invention.

[0036] 1 and 2, 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 surrounds the battery cell stack 120.

[0037] First, 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 and 112 face each other and protrude from one end 114a and the other end 114b of a cell body 113, respectively. That is, the battery cell 110 includes the electrode leads 111 and 112 protruding in opposite directions. More specifically, the electrode leads 111 and 112 are connected to an electrode assembly (not shown) and protrude from the electrode assembly (not shown) to the outside of the battery cell 110.

[0038] Meanwhile, the battery cell 110 may be manufactured by bonding both ends 114a, 114b of the cell case 114 and one side 114c connecting them together while the electrode assembly (not shown) is received in the cell case 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 may be sealed by a method such as heat fusion, and the other side may be the connecting portion 115. The cell case 114 may be made of a laminate sheet including a resin layer and a metal layer.

[0039] Furthermore, the connecting portion 115 may extend long along one edge of the battery cell 110, and a butt ear 110p may be formed at the end of the connecting portion 115. Furthermore, the cell casing 114 may be sealed with the protruding electrode leads 111, 112 sandwiched therebetween, and a terrace portion 116 may be formed between the electrode leads 111, 112 and the cell body 113. In other words, the battery cell 110 may include a terrace portion 116 formed by extending from the cell casing 114 in the direction in which the electrode leads 111, 112 protrude.

[0040] 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. 1, the plurality of battery cells 110 may be stacked along a direction parallel to the y-axis. As a result, the electrode leads 111, 112, etc. may protrude in the x-axis direction and the -x-axis direction, respectively.

[0041] Meanwhile, repeated charging and discharging of the battery cell 110 generates heat, and a large amount of heat is generated in the areas adjacent to the electrode leads 111 and 112. In other words, more heat is generated by charging and discharging closer to the electrode leads 111 and 112 than in the center of the cell body 113, so a structure for cooling these areas is required.

[0042] Meanwhile, 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 300a that supports the bottom of the battery cell stack 120 and side portions that extend upward from both ends of the bottom 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 may cover the open upper side of the module frame 200. The end plates 150 may cover the front and rear sides of the battery cell stack 120 that are open on the module frame 200. The end plates 150 may 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.

[0044] A busbar frame 130 may be formed between the end plate 150 and the front and rear surfaces of the battery cell stack 120. The busbar frame 130 may cover the portion of the battery cell stack 120 exposed from the module frame 200. In addition, a plurality of busbars 160 attached to the busbar frame 130 may be formed to protrude from the battery cells 110, etc., and connected to the electrode leads 111, 112, etc. attached to the busbar frame 130. In this case, slots 164 through which the electrode leads 111, 112 pass may be formed in the busbar 160. Therefore, the busbar 160 may be divided into two regions by the slots 164.

[0045] In addition, the battery module 100 according to this embodiment further includes a 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 thermally conductive resin layer 310 transfers heat generated in the battery cells 110 to the bottom of the battery module 100 and serves to fix the battery cell stack 120 in place.

[0046] In conventional battery modules, heat generated in the battery cells is dissipated through a thermally conductive resin layer formed under the battery cells. However, the thermally conductive resin layer cannot efficiently cool the heat generated in the electrode leads and bus bar frame on the front and rear of the battery cells, and the bus bars attached to the bus bar frame.

[0047] Therefore, in situations such as rapid charging where a high current flow causes a large amount of heat to be generated in the electrode leads and bus bars of the battery cells in a short period of time, a structure that can effectively cool the generated heat is required.

[0048] Therefore, according to this embodiment, a cooling channel 165 is provided inside the bus bar 160, and a refrigerant is taken in through the cooling channel 165, thereby making it possible to cool the bus bar 160 and the electrode leads 111, 112 connected to the bus bar 160, thereby cooling the bus bar 160 and the electrode leads 111, 112. This prevents temperature rise, temperature deviation, and performance degradation of the battery module, and ensures the safety of the battery module.

[0049] Hereinafter, a bus bar included in a battery module according to an embodiment of the present invention will be described in detail with reference to FIGS.

[0050] Fig. 3 is a perspective view showing a busbar according to an embodiment of the present invention. Fig. 4 is a perspective view showing cooling channels formed in the busbar of Fig. 3. Fig. 5 is an enlarged view of a portion cut along the P2 plane of Fig. 3. Fig. 6 is a cross-sectional view cut along the P1 plane of Fig. 2.

[0051] 4 and 5, the bus bar 160 according to this embodiment is formed with a cooling channel 165. In this case, the cooling channel 165 is not particularly limited, but may be a tubular shape formed in the bus bar 160 as a structure for cooling the bus bar 160 and the electrode leads 111 and 112 connected to the bus bar 160.

[0052] The cooling channels 165 may be formed inside the bus bar 160. Therefore, the cooling channels 165 may be formed inside the bus bar 160 and serve as paths through which the coolant flows. The cooling channels 165 are formed inside the bus bar 160 so as not to be exposed to the outside, and thus may form a stable flow of the coolant.

[0053] The cooling flow passages 165 may be formed perpendicular to the direction in which the slots 164 of the bus bar 160 are formed, or may be formed parallel to the direction in which the slots 164 of the bus bar 160 are formed. Specifically, the cooling flow passages 165 may include a first flow passage 165a and a third flow passage 165c formed perpendicular to the direction in which the slots 164 are formed, and a second flow passage 165b formed parallel to the direction in which the slots 164 are formed.

[0054] A plurality of flow paths 165 may be formed. In particular, a plurality of second flow paths 165b may be formed in bus bar 160, thereby cooling bus bar 160 that is in contact with electrode leads 111, 112, thereby improving the cooling performance of the battery module. Also, although FIG. 4 shows a single first flow path 165a and a single third flow path 165c, a plurality of first flow paths 165a and a single third flow path 165c may be formed so as to be connected to second flow path 165b.

[0055] In this case, first flow path 165a may connect the two regions of bus bar 160. Accordingly, third flow path 165c may also connect the two regions of bus bar 160. In other words, first flow path 165a and third flow path 165c may be formed to connect the two regions of bus bar 160 separated by slots 164 of bus bar 160, so that the refrigerant flow may be transferred from one region to the other.

[0056] In addition, the first flow path 165a and the third flow path 165c are formed at the upper and lower ends of the bus bar 160, respectively, and the second flow path 165b can connect the first flow path 165a and the third flow path 165c formed at the upper and lower ends of the bus bar 160. Therefore, a continuous refrigerant flow is formed through the first flow path 165a, the second flow path 165b, and the third flow path 165c, thereby cooling the bus bar 160 and improving the cooling performance of the battery module 100.

[0057] Meanwhile, the battery module according to this embodiment may further include a refrigerant inlet 161 formed at one end of the bus bar 160 and a refrigerant outlet 162 formed at the other end of the bus bar 160 .

[0058] 3 and 4, refrigerant inlet 161 may be connected to first passage 165a. Also, refrigerant outlet 162 may be connected to third passage 165c. Therefore, the refrigerant transferred through refrigerant inlet 161 flows into cooling passage 165 through first passage 165a, and the transferred refrigerant is transferred to refrigerant outlet 162 through third passage 165c and can then flow out to the outside.

[0059] In this case, the refrigerant inlet 161 and the refrigerant outlet 162 may be made of a non-conductive material. The material may be selected without limitation as long as it satisfies the performance of the refrigerant inlet 161 and the refrigerant outlet 162. Therefore, even if the refrigerant inlet 161 and the refrigerant outlet 162 are formed, insulation within the battery module 100 can be ensured. In this case, the non-conductive material is not limited to a specific material, but may include a synthetic resin material.

[0060] Meanwhile, the refrigerant inlet 161 may be formed at the upper end of the bus bar 160. Also, the refrigerant outlet 162 may be formed at the lower end of the bus bar 160. This allows for the flow of the refrigerant due to gravity. However, the refrigerant inlet 161 may be formed at the lower end of the bus bar 160, and the refrigerant outlet 162 may be formed at the upper end of the bus bar 160. In this case, the refrigerant flow can be formed by including an additional component such as a pump to form the refrigerant flow.

[0061] As described above, the battery module 100 according to this embodiment may further include a coolant flowing along the cooling flow path 165. The coolant may also include cooling water. In this case, to maintain and ensure insulation within the battery module 100, the cooling water may include insulating cooling water.

[0062] As a result, the battery module according to this embodiment may include a plurality of bus bars 160, and each bus bar 160 may be formed with a cooling channel 165. Therefore, referring to Fig. 6, in addition to the existing heat transfer path for discharging heat generated in the battery cells 110 via the thermally conductive resin layer 310 located below the battery cell stack 120, additional paths for discharging heat to the outside via the cooling channel 165 and the refrigerant are provided, thereby diversifying the heat transfer paths and further improving the cooling performance of the battery module.

[0063] A battery pack according to another embodiment of the present invention will now be described.

[0064] The battery pack according to this embodiment includes the battery module described above. The battery pack of the present invention may be configured by assembling one or more battery modules according to this embodiment and adding a battery management system (BMS) for managing the temperature and voltage of the battery, a cooling device, etc.

[0065] The battery pack may 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 may be applied to various devices using battery modules, which also fall within the scope of the present invention.

[0066] 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 skill in the art 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]

[0067] 100: Battery module 110: Battery cell 120: Battery cell stack 130: Bus bar frame 150: End plate 160: Busbar 165: Cooling channel 200:Module frame 300: U-shaped frame 400: Upper plate

Claims

1. a battery cell stack in which a plurality of battery cells are stacked; a module frame that surrounds the battery cell stack; a bus bar frame that covers a portion of the battery cell stack that is exposed from the module frame; and a bus bar attached to the bus bar frame and connected to an electrode lead protruding from the battery cell stack; The bus bar has a cooling passage formed therein. The bus bar is formed with a slot through which the electrode lead passes, the slot extends along at least half of the longitudinal dimension of the busbar; The cooling flow path includes a first flow path and a third flow path formed perpendicular to a direction in which the slots are formed, and a second flow path formed parallel to the direction in which the slots are formed.

2. The battery module according to claim 1 , wherein the cooling flow path is formed inside the bus bar and serves as a passage through which a coolant flows.

3. the bus bar is divided into two regions by the slot; The battery module according to claim 1 , wherein the first flow path and the third flow path connect two regions of the bus bar.

4. 4. The battery module of claim 3, wherein the first flow path and the third flow path are formed at upper and lower ends of the bus bar, respectively, and the second flow path connects the first flow path and the third flow path formed at the upper and lower ends of the bus bar, respectively.

5. The battery module of claim 1 , further comprising: a refrigerant inlet formed at one end of the bus bar; and a refrigerant outlet formed at the other end of the bus bar.

6. The battery module according to claim 5 , wherein the coolant inlet and the coolant outlet are made of a non-conductive material.

7. the refrigerant inlet is formed at an upper end of the bus bar; The battery module according to claim 5 , wherein the refrigerant outlet is formed at a lower end of the bus bar.

8. the refrigerant includes cooling water; The battery module according to claim 2 , wherein the cooling water includes insulating cooling water.

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

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