Specification
Title of Invention: Battery module and battery pack including same
technical field
[One]
Cross-Citation with Related Application(s)
[2]
This application claims the benefit of priority based on Korean Patent Application No. 10-2020-0032725 dated March 17, 2020, and all contents disclosed in the literature of the Korean patent application are incorporated as a part of this specification.
[3]
The present invention relates to a battery module and a battery pack including the same, and more particularly, to a battery module that prevents deformation of a module structure due to swelling, and a battery pack including the same.
background
[4]
In modern society, as the use of portable devices such as mobile phones, laptops, camcorders, and digital cameras has become commonplace, the development of technologies related to mobile devices as described above has been active. In addition, a rechargeable battery capable of charging and discharging is a measure to solve air pollution such as conventional gasoline vehicles using fossil fuels, and electric vehicles (EVs), hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles ( P-HEV) is being used as a power source, and the need for the development of secondary batteries is increasing.
[5]
Currently commercialized secondary batteries include nickel-cadmium batteries, nickel-hydrogen batteries, nickel-zinc batteries, and lithium secondary batteries. Among them, lithium secondary batteries have little memory effect compared to nickel-based secondary batteries, so they can be charged and discharged freely. , the self-discharge rate is very low and the energy density is high.
[6]
Such a lithium secondary battery mainly uses a lithium-based oxide and a carbon material as a positive electrode active material and a negative electrode active material, respectively. A lithium secondary battery includes an electrode assembly in which a positive electrode plate and a negative electrode plate to which the positive electrode active material and the negative electrode active material are respectively applied with a separator interposed therebetween, and a battery case for sealingly accommodating the electrode assembly together with an electrolyte.
[7]
In general, a lithium secondary battery may be classified into a can-type secondary battery in which an electrode assembly is embedded in a metal can and a pouch-type secondary battery in which an electrode assembly is embedded in a pouch of an aluminum laminate sheet according to the shape of the exterior material.
[8]
In the case of secondary batteries used in small devices, 2-3 battery cells are disposed, but in the case of secondary batteries used in mid- to large-sized devices such as automobiles, a battery module in which a plurality of battery cells are electrically connected this is used In such a battery module, a plurality of battery cells are connected in series or parallel to each other to form a battery cell stack, thereby improving capacity and output. In addition, one or more battery modules may be mounted together with various control and protection systems, such as a battery management system (BMS) and a cooling system, to form a battery pack.
[9]
1 is a view showing a conventional battery module.
[10]
Referring to FIG. 1 , the battery module includes a battery cell stack 12 formed by stacking a plurality of battery cells 11 , a mono frame 20 with front and rear open sides to accommodate the battery cell stack 12 , and An end plate 60 covering the front and rear surfaces of the mono frame 20 may be included. In order to form such a battery module, horizontal assembly in which the battery cell stack 12 is inserted into the open front or rear surface of the mono frame 20 along the X-axis direction is required as shown in the arrow shown in FIG. 1 . However, sufficient tolerance must be secured between the battery cell stack 12 and the mono frame 20 so that the horizontal assembly can be stably performed. Here, the tolerance refers to a gap generated by fitting or the like.
[11]
At this time, the height of the monoframe 20 should be designed to be large in consideration of the maximum height of the battery cell stack 12 and the assembly tolerance in the insertion process, and thus an unnecessary wasted space may occur.
[12]
On the other hand, in the process of repeatedly charging and discharging the plurality of battery cells 11, the internal electrolyte is decomposed and gas is generated, so that the battery cell 11 swells, that is, a swelling phenomenon may occur. . When the plurality of battery cells 11 stacked at a high degree of integration swell, there is a problem in that only both sides of the mono frame 20 have to withstand pressure due to swelling.
[13]
However, when the thickness of the mono frame 20 is increased, the thickness of the upper and lower surfaces, which are independent of the rigidity against the swelling phenomenon, also increases, so that the weight of the battery module increases more than necessary, and the height is also increased to increase the energy capacity. There are disadvantages in terms of
[14]
On the other hand, since the battery cell stack 12 is formed by compactly stacking a plurality of battery cells 11 , a temperature deviation between the battery cells 11 of the battery cell stack 12 may intensify. The temperature non-uniformity between the battery cells 11 may deteriorate the performance of the battery module and ultimately reduce the lifespan.
DETAILED DESCRIPTION OF THE INVENTION
technical challenge
[15]
An object of the present invention is to provide a battery module capable of controlling swelling and temperature deviation of battery cells while minimizing an increase in weight or height, and a battery pack including the same.
[16]
However, the problems to be solved by the embodiments of the present invention are not limited to the above problems and may be variously expanded within the scope of the technical idea included in the present invention.
means of solving the problem
[17]
A battery module according to an embodiment of the present invention includes a battery cell stack in which a plurality of battery cells are stacked; a first frame covering a lower portion of the battery cell stack; and a second frame covering an upper portion of the battery cell stack, wherein the first frame includes first side portions covering both sides of the battery cell stack, and the second frame includes the first side portions It includes second side parts for covering, and a side member is positioned between the first side part and the second side part.
[18]
The second frame may include a front portion and a rear portion respectively covering the front and rear surfaces of the battery cell stack.
[19]
The side member may include polyurethane.
[20]
The battery body of the battery cell may be disposed parallel to the first side parts, the second side parts, and the side member.
[21]
The side member may be in the form of a pad.
[22]
The battery module may include an end plate that covers the front and rear surfaces of the battery cell stack.
[23]
The end plate may be welded to at least one of the first frame and the second frame.
[24]
The battery module may further include a polymer resin layer formed on at least one of between the first side part and the side member and between the second side part and the side member.
[25]
The polymer resin layer may be formed by coating the side member with a polymer resin.
Effects of the Invention
[26]
The battery module and the battery pack including the same according to an embodiment of the present invention, by adopting a double frame structure at a position adjacent to one surface of the battery cell stack to which the force due to the swelling of the battery cells acts, the weight of the battery module or It is possible to prevent the deformation of the module structure due to swelling while minimizing the increase in height.
[27]
In addition, by providing a side member to block heat transfer to the outside of the battery module, it is possible to reduce the temperature deviation between the battery cells. Accordingly, it is possible to increase the performance and lifespan of the battery module.
[28]
Effects of the present invention are not limited to the effects mentioned above, and other effects not mentioned will be clearly understood by those skilled in the art from the description of the claims.
Brief description of the drawing
[29]
1 is an exploded perspective view of a conventional battery module.
[30]
2 is an exploded perspective view showing a battery module according to an embodiment of the present invention.
[31]
3 is a view showing a state in which the battery module of FIG. 2 is assembled.
[32]
4 is a cross-sectional view of a battery module according to an embodiment of the present invention, taken along line A-A of FIG. 3 .
[33]
5 is a perspective view illustrating a battery cell included in the battery module of FIG. 2 .
[34]
6 is an exploded perspective view showing a battery module according to another embodiment of the present invention.
[35]
7 is a cross-sectional view of a battery module according to another embodiment of the present invention.
Modes for carrying out the invention
[36]
Hereinafter, with reference to the accompanying drawings, various embodiments of the present invention will be described in detail so that those of ordinary skill in the art can easily carry out the present invention. The present invention may be embodied in many different forms and is not limited to the embodiments described herein.
[37]
In order to clearly explain the present invention, parts irrelevant to the description are omitted, and the same reference numerals are assigned to the same or similar elements throughout the specification.
[38]
In addition, since the size and thickness of each component shown in the drawings are arbitrarily indicated for convenience of description, the present invention is not necessarily limited to the illustrated bar. In order to clearly express various layers and regions in the drawings, the thicknesses are enlarged. And in the drawings, for convenience of description, the thickness of some layers and regions are exaggerated.
[39]
Also, when a part of a layer, film, region, plate, etc. is said to be “on” or “on” another part, it includes not only cases where it is “directly on” another part, but also cases where there is another part in between. . Conversely, when we say that a part is "just above" another part, we mean that there is no other part in the middle. In addition, to be "on" or "on" the reference part means to be located above or below the reference part, and it means to be located "on" or "on" the direction opposite to gravity. not.
[40]
In addition, throughout the specification, when a part "includes" a certain component, this means that other components may be further included, rather than excluding other components, unless otherwise stated.
[41]
In addition, throughout the specification, when referring to "planar view", it means when the target part is viewed from above, and "cross-sectional view" means when viewed from the side when a cross-section of the target part is vertically cut.
[42]
2 is an exploded perspective view showing a battery module according to an embodiment of the present invention. 3 isIt is a view showing a state in which the battery module of FIG. 2 is assembled. 4 is a cross-sectional view of a battery module according to an embodiment of the present invention, taken along line A-A of FIG. 3 .
[43]
2 to 4 , the battery module according to an embodiment of the present invention covers the lower portion of the battery cell stack 100 in which a plurality of battery cells 110 are stacked, and the battery cell stack 100 . It includes a second frame 300 covering an upper portion of the first frame 200 and the battery cell stack 100 . The first frame 200 includes first side portions 210 covering both sides of the battery cell stack 100 , and the second frame 300 includes a second side portion ( 310 , and the side member 400 is positioned between the first side part 210 and the second side part 310 .
[44]
The first frame 200 may further include a bottom portion 220 covering the lower surface of the battery cell stack 100 . That is, the first frame 200 may be formed to cover both sides and a lower surface of the battery cell stack 100 . In this case, the first side portions 210 and the bottom portion 220 of the first frame 200 may be integrally formed.
[45]
The second frame 300 includes a ceiling portion 320 that covers the upper surface of the battery cell stack 100 , a front portion 330 that covers the front surface of the battery cell stack 100 , and the battery cell stack 100 ). It may further include a rear portion 340 to cover the rear surface of the. That is, the second frame 300 may be formed to cover both sides, the top surface, the front surface, and the rear surface of the battery cell stack 100 . In this case, the second side parts 310 , the ceiling part 320 , the front part 330 , and the rear part 340 may be integrally formed.
[46]
According to the present embodiment, the ceiling portion 320 of the second frame is the first so that the second side portion 310 of the second frame 300 can cover the first side portion 210 of the first frame 200 . It may be formed wider than the bottom 220 of the frame 200 .
[47]
5 is a perspective view illustrating a battery cell included in the battery module of FIG. 2 .
[48]
Referring to FIG. 5 , the battery cell 110 according to an embodiment of the present invention is preferably a pouch-type battery cell. For example, in the battery cell 110 according to the present embodiment, the two electrode leads 111 and 112 are opposite to each other and protrude from one end 114a and the other end 114b of the battery body 113, respectively. has a structure in In more detail, the electrode leads 111 and 112 are connected to the electrode assembly (not shown) and protrude from the electrode assembly (not shown) to the outside of the battery cell 110 .
[49]
Meanwhile, in the battery cell 110 , both ends 114a and 114b of the battery case 114 and one side 114c connecting them are adhered in a state in which an electrode assembly (not shown) is accommodated in the battery case 114 . It can be manufactured by In other words, the battery cell 110 according to the present embodiment has a total of three sealing portions 114sa, 114sb, 114sc, and the sealing portions 114sa, 114sb, 114sc are sealed by a method such as thermal fusion. , the other one side may be formed of a connection part 115 . In addition, the connection part 115 may extend along one edge of the battery cell 110 , and a protrusion 110p of the battery cell 110 called a bat-ear is formed at an end of the connection part 115 . can be
[50]
As shown in FIG. 2 , the battery cells 110 may be stacked in a direction perpendicular to the first side part 210 or the second side part 310 to form the battery cell stack 100 . That is, the battery body 113 of the battery cell 110 may be disposed in parallel with the first side parts 210 , the second side parts 310 , and the side member 400 to be described later. Accordingly, the electrode leads 111 and 112 of the plurality of battery cells 110 may protrude toward the front portion 330 and the rear portion 340 of the second frame 300 , respectively.
[51]
At this time, in the battery cell 110, the electrode may expand during repeated charging and discharging, or the internal electrolyte may be decomposed due to a side reaction to generate gas. At this time, a phenomenon in which the battery cell 110 swells due to electrode expansion or generated gas is referred to as a swelling phenomenon. When the swelling phenomenon of the battery cell 110 intensifies, the external shape of the battery module may be changed, thereby adversely affecting the structural stability of the battery module or a battery pack including the same.
[52]
In particular, it is easily inflated in a vertical direction rather than a direction parallel to the battery body 113 . Therefore, the pressure due to the swelling of the battery cells 110 included in the battery cell stack 100 may act greatly in the direction of the first side part 210 and the second side part 310 .
[53]
Conventionally, the frame structure formed at a position adjacent to the battery cell stack along the stacking direction of the battery cells is formed as a single frame structure, so that it is difficult to prevent structural deformation of the battery module when swelling occurs. However, if the thickness of the frame is increased, the thickness of the upper surface or the lower surface, which is irrelevant to the rigidity against swelling, also increases, so the weight of the battery module increases more than necessary, and the height is also increased, so there is a disadvantage in terms of energy capacity. have.
[54]
Accordingly, according to an embodiment of the present invention, with respect to the battery cell stack 100 , the first side portion 210 of the first frame 200 and the second side portion 310 of the second frame 300 are double frames. By forming the structure, it is possible to effectively prevent a structural change of the battery module due to swelling of the battery cells 110 .
[55]
In particular, both side portions of the frame may be implemented to be thicker so that the swelling phenomenon of the battery cell 110 can be directly controlled, and at the same time, the bottom and ceiling portions, which are less related to swelling, are implemented to be relatively thin, so the battery module It is possible to prevent unnecessary increase in volume or weight. That is, when the bottom 220 and the ceiling 320 have a first thickness t, as shown in FIG. 4 , the first side part 210 and the second side part 310 are positioned together to form the second side in the lateral direction. 2 The thickness (2t) effect can be implemented. In other words, the side thickness of the frame may be increased through the first side part 210 and the second side part 310 in consideration of the swelling direction of the battery cell 110 .
[56]
In addition, according to the present embodiment, the side member 400 is positioned between the first side part 210 and the second side part 310 . The side member 400 may be in the form of a pad, and preferably has a predetermined elastic force. In particular, the side member 400 may be in the form of a pad including foam. Since the side member 400 can effectively absorb the swelling of the battery cells 110 , the structural stability of the battery module with respect to the swelling of the battery cells 110 can be further improved.
[57]
That is, through the first side part 210 and the second side part 310 , the rigidity of the frame in the lateral direction in which the swelling of the battery cell 110 is mainly a problem can be increased, and at the same time, the side member 400 is positioned Thus, swelling of the battery cell 110 can be effectively absorbed.
[58]
In addition, in the space formed by the first side part 210 and the second side part 310 , the pad-shaped side member 400 as in the present embodiment is easily disposed.
[59]
The battery cell stack 100 is formed by compactly stacking a plurality of battery cells 110 . Among them, since the outermost battery cell 110 is more affected by the external environment, the outermost battery cell 110 may have a relatively lower temperature, and thus the battery of the battery cell stack 100 . A temperature difference between the cells 110 may intensify. The temperature non-uniformity between the battery cells 110 may cause lowering of the performance and lifespan of the battery module.

Claims

[Claim 1]
a battery cell stack in which a plurality of battery cells are stacked; a first frame covering a lower portion of the battery cell stack; and a second frame covering an upper portion of the battery cell stack, wherein the first frame includes first side portions covering both sides of the battery cell stack, and the second frame includes the first side portions A battery module comprising second side parts for covering, and a side member positioned between the first side part and the second side part.
[Claim 2]
The battery module of claim 1, wherein the second frame includes a front portion and a rear portion respectively covering the front and rear surfaces of the battery cell stack.
[Claim 3]
The battery module of claim 1 , wherein the side member comprises polyurethane.
[Claim 4]
The battery module of claim 1, wherein the battery body of the battery cell is disposed parallel to the first side parts, the second side parts, and the side member.
[Claim 5]
The battery module of claim 1, wherein the side member has a pad shape.
[Claim 6]
The battery module of claim 1, comprising an end plate covering the front and rear surfaces of the battery cell stack.
[Claim 7]
The battery module of claim 6, wherein the end plate is welded to at least one of the first frame and the second frame.
[Claim 8]
The battery module of claim 1, further comprising a polymer resin layer formed on at least one of between the first side part and the side member and between the second side part and the side member.
[Claim 9]
The battery module of claim 8, wherein the polymer resin layer is formed by coating a polymer resin on the side member.
[Claim 10]
A battery pack comprising the battery module according to claim 1 .