The present invention relates to a battery module and a battery pack including the same, and more particularly, to a battery module having a swelling gauge capable of intuitively observing the swelling amount of battery cells, and a battery pack including the same .
[2]
This application is a priority claim application for Korean Patent Application No. 10-2019-0002470 filed on January 08, 2019, and all contents disclosed in the specification and drawings of the application are incorporated herein by reference.
background
[3]
Secondary batteries are highly applicable to various product groups and have electrical characteristics with high energy density. Such secondary batteries are being applied to electric vehicles or hybrid vehicles driven by an electric driving source as well as portable electronic devices, power storage devices, and the like.
[4]
A battery pack applied to an electric vehicle has a structure in which a plurality of battery modules including a plurality of battery cells are connected to obtain high output. Each battery cell is an electrode assembly, and can be repeatedly charged and discharged through an electrochemical reaction between components, including positive and negative current collectors, separators, active materials, electrolytes, and the like.
[5]
On the other hand, in the case of the battery cells of the battery module, a swelling phenomenon in which the battery cells swell during repeated charging and discharging occurs. In consideration of the swelling phenomenon, in the conventional battery module, when the battery cells are stacked, the battery cells are spaced apart from each other at regular intervals, or a compression pad for supporting the battery cells is disposed between the battery cells during swelling.
[6]
However, if the above-described compression pad is used for the battery module or if the battery cells are spaced apart, there is a problem in that the energy density per unit volume is reduced accordingly. In addition, when the compression pad is used between the battery cells, there is a problem in that the manufacturing process of the battery module is complicated and the manufacturing cost of the battery module is increased. Therefore, it needs improvement.
[7]
In addition, since the swelling of the battery cells is related to the safety of the battery module, it is very important to determine whether the swelling has occurred and how much deformation has occurred if the swelling has occurred.
[8]
However, in the related art, the amount of swelling of the battery cells is indirectly inferred by estimating the swelling of the internal battery cells based on the external appearance of the battery module, or indirectly through structural analysis techniques and measurement of the dimensions of the experimental module. For this reason, it is more difficult for the general user to know exactly how much the battery cells inside the battery module have swelled. Accordingly, there is a need for a method in which anyone, including those skilled in the art, as well as general users, can easily check whether the battery cells have swollen and the amount of swelling.
DETAILED DESCRIPTION OF THE INVENTION
technical challenge
[9]
In order to solve the above-described problem, the present invention provides a method for alleviating the swelling of the battery cells without reducing the energy density of the battery module, and a method for intuitively and easily grasping the amount of swelling of the battery cells from the outside of the battery module. Its purpose is to provide a solution.
means of solving the problem
[10]
According to one aspect of the present invention, there is provided a battery module that can intuitively check the swelling amount of battery cells accommodated in a module housing, in the longitudinal direction of a cell stack accommodated in the module housing and formed by stacking the battery cells. a cell pressure plate disposed to face at least one of both sides; and a swelling gauge provided to protrude from the surface of the cell pressure plate, wherein when the battery cells expand, the swelling gauge is pushed out of the module housing through a gauge hole formed in the module housing. A battery module that comes out may be provided.
[11]
A buffer member may be further interposed in a space between the cell pressure plate and the module housing.
[12]
The buffer member may be a leaf spring.
[13]
The leaf spring may have at least one curvature, and one surface thereof may be in contact with the surface of the cell pressure plate and the other surface may be disposed in contact with the surface of the module housing.
[14]
The leaf spring may have a plate hole through which the swelling gauge passes, and may be disposed in contact with the cell pressure plate while being suspended from the swelling gauge.
[15]
The swelling gauge may be located in the center of the cell pressure plate.
[16]
The swelling gauge may include: a first swelling gauge located in the center of the cell pressure plate; and a second swelling gauge and a third swelling gauge provided on both edge regions along the longitudinal direction of the cell pressure plate.
[17]
The module housing may include a top plate disposed on the cell stack, a bottom plate disposed under the cell stack, and the gauge hole, and a pair of sides disposed on both side portions of the cell stack, respectively. It can be formed by assembling the plates together.
[18]
The top plate and the bottom plate include bent portions provided by bending both edge regions in the longitudinal direction, and the pair of side plates include step portions provided with both edge regions in the longitudinal direction to be stepped, the step portion It may be shape-fitted to the inside of the bent portion.
[19]
According to another aspect of the present invention, a battery pack including the above-described battery module may be provided.
Effects of the Invention
[20]
According to one aspect of the present invention, there is provided a battery module capable of reducing swelling of battery cells without degrading the energy density of the battery module and capable of intuitively grasping the amount of swelling of the battery cells from the outside of the battery module. can
[21]
Effects of the present invention are not limited to the above-described effects, and effects not mentioned will be clearly understood by those of ordinary skill in the art to which the present invention belongs from the present specification and accompanying drawings.
Brief description of the drawing
[22]
1 is a schematic perspective view of a battery module according to an embodiment of the present invention.
[23]
FIG. 2 is a partially exploded perspective view of the battery module of FIG. 1 .
[24]
3 is an exploded perspective view of a cell pressure plate, a buffer member, and a side plate according to an embodiment of the present invention.
[25]
4 is a cross-sectional view taken along line I-I' of FIG. 1 .
[26]
FIG. 5 is an enlarged cross-sectional view of a main part when swelling of the battery cells of FIG. 4 is performed.
[27]
6 is an exploded perspective view of a cell pressure plate, a buffer member, and a side plate according to another embodiment of the present invention.
Modes for carrying out the invention
[28]
Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. Prior to this, the terms or words used in the present specification and claims should not be construed as being limited to their ordinary or dictionary meanings, and the inventor should properly understand the concept of the term in order to best describe his invention. Based on the principle that it can be defined, it should be interpreted as meaning and concept consistent with the technical idea of ​​the present invention. Accordingly, the embodiments described in the present specification and the configurations shown in the drawings are only some of the most preferred embodiments of the present invention and do not represent all the technical spirit of the present invention. It should be understood that there may be equivalents and variations.
[29]
1 is a schematic perspective view of a battery module according to an embodiment of the present invention, and FIG. 2 is a partially exploded perspective view of the battery module of FIG. 1 . 3 is an exploded perspective view of a cell pressure plate, a buffer member, and a side plate according to an embodiment of the present invention.
[30]
Referring to these drawings, the battery module 1 according to an embodiment of the present invention includes a cell stack 10 , a module housing 20 , a cell pressure plate 30 , a buffer member 40 , and a swelling gauge 50 . ) is included.
[31]
The cell stack 10 may be an assembly of battery cells 11 including pouch-type battery cells 11 stacked with wide sides facing each other. In other words, in the present embodiment, the cell stack 10 is configured to be as densely arranged as possible in the module housing 20 in a form in which the pouch-type battery cells 11 are placed side by side and stacked in the horizontal direction.
[32]
The pouch-type battery cells 11 refer to a secondary battery composed of a pouch case, an electrode assembly provided to be accommodated in the pouch case, and an electrolyte. For example, the pouch-type exterior material may be composed of two pouches, and a concave inner space may be formed in at least one of them. And the electrode assembly may be accommodated in the inner space of the pouch. The periphery of the two pouches is fused to each other, so that the inner space in which the electrode assembly is accommodated may be sealed. An electrode lead 12 may be attached to the electrode assembly, and the electrode lead 12 is interposed between the fusion portions of the pouch casing and exposed to the outside of the pouch casing to function as an electrode terminal of the battery cell 11 . have.
[33]
Although not shown in detail for convenience of drawing, the battery cells 11 may be connected in series and/or in parallel by welding electrode leads 12 to bus bars (not shown) provided on an ICB board (not shown). The ICB board and bus bars may be shielded by module covers 61 and 62 .
[34]
The module housing 20 has an internal space capable of accommodating the cell stack 10 , and serves to provide mechanical support for the housed battery cells 11 and to protect from external impact. Therefore, it may be preferable that the module housing 20 be made of a metal material to ensure rigidity. Of course, the scope of the present invention is not limited to the module housing 20 made of metal.
[35]
As shown in FIG. 2 , the module housing 20 according to an embodiment of the present invention includes a top plate 21 , a bottom plate 22 , left side plates 23 and 24 , and right side plates 23 and 24 . ), including 4 plates composed of
[36]
The top plate 21 is disposed on the top of the cell stack 10 , and the bottom plate 22 is disposed on the bottom of the cell stack 10 . In addition, the pair of side plates 23 and 24 are respectively disposed on the left side and the right side of the cell stack 10 in the longitudinal direction. These four plates are mutually assembled to form each tubular module housing 20 . For example, the four plates may be assembled to each other in a snap-fit ​​or welding manner.
[37]
In particular, the module housing 20 of the present embodiment has an assembly structure that can well withstand the force acting from the inside of the module housing 20 to the outside in consideration of the swelling of the battery cells 11 .
[38]
To this end, (refer to FIG. 4 ) the top plate 21 and the bottom plate 22 include bent portions 21a and 22a provided by bending both edge regions in the longitudinal direction, and a pair of side plates 23 , 24) includes a step portion 23a in which both edge regions along the longitudinal direction are provided with a step difference.
[39]
The stepped portions 23a of the side plates 23 and 24 are shape-fitted inside the bent portions 21a and 22a of the top plate 21 and the bottom plate 22 . In this case, when a force is applied from the inside of the module housing 20 to the outside, the top plate 21 and the bottom plate 22 hold the side plates 23 and 24 to prevent deformation of the side plates 23 and 24 . can be reduced
[40]
As a measure for alleviating the swelling of the battery cells 11 in the module housing 20 , as shown in FIG. 4 , a cell pressure plate 30 is disposed between the side plates 23 and 24 and the outermost battery cell 11 . ) and the buffer member 40 are further disposed.
[41]
In other words, the cell pressure plate 30 is disposed to face the entire area of ​​both side surfaces in the longitudinal direction of the cell stack 10 , and a buffer member 40 is disposed between the cell pressure plate 30 and the side plates 23 and 24 . ) is interposed.
[42]
The cell pressure plate 30 may be adhered to the outermost battery cell 11 as a method of securing adhesion with the cell stack 10 . And a leaf spring 40 is employed as the buffer member 40 . The leaf spring 40 has at least one curved shape repeatedly formed in the vertical direction, and one surface thereof is in contact with the cell pressure plate 30 and the other surface thereof is disposed in contact with the side plates 23 and 24 . As an alternative to the leaf spring 40, a compression form or a rubber pad may be employed.
[43]
In this embodiment, the cell pressure plate 30 and the buffer member 40 are paired as a pair, and a total of two pairs of the cell pressure plate 30 and the buffer member 40 are disposed on both sides of the cell stack 10 to form a battery cell. (11) strengthened the buffering power during the swelling. However, by arranging the cell pressure plate 30 and the buffer member 40 only on one side of the cell stack 10 , and securing more space for adding the battery cell 11 in the module housing 20 , the energy density is further increased. The height design is also possible.
[44]
According to this configuration, the cell stack 10 in the module housing 20 may be constrained in an elastically pressed state by the leaf spring 40 and the cell pressure plate 30 . In this case, the pressing force of the cell pressure plate 30 and the expansion force of the battery cells 11 may be offset, so that the degree of swelling of the battery cells 11 during charging and discharging may be alleviated.
[45]
When the expansion force of the battery cells 11 is stronger than the pressing force of the cell pressure plate 30 , the leaf spring 40 of FIG. 4 is deformed like the leaf spring 40 of FIG. 5 . That is, the leaf spring 40 is extended in the vertical direction while the curved or wrinkled pattern is unfolded. As described above, since the leaf spring 40 is deformed to absorb some of the expansion force of the battery cells 11 , the outer shape of the module housing 20 may be less deformed. For reference, when the module housing 20 is expanded, pressure is applied not only to the battery module 1 but also to other battery modules 1 or electronic devices adjacent to the battery module 1, which is not good for safety.
[46]
On the other hand, the battery module 1 of the present invention further includes a swelling gauge 50 so that when the battery cells 11 swell, the degree of swelling can be easily known. As will be described later in detail, the swelling gauge 50 is provided so that it can be checked from the outside of the battery module 1 , so that anyone can intuitively grasp the amount of swelling of the battery cells 11 . Accordingly, the user may stop using the battery module 1 by looking at the swelling gauge 50 or may replace the battery module 1 in advance by estimating the lifespan of the battery module 1 .
[47]
Hereinafter, the structure and utilization of the swelling gauge 50 will be described in detail with reference to FIGS. 3 to 5 again.
[48]
The swelling gauge 50 may protrude from the surface of the cell pressure plate 30 and may be integrally formed with the cell pressure plate 30 . For example, the swelling gauge 50 may be any shape capable of measuring a length, such as a circular column, a polygonal column, or a steel shape. In addition, it is also possible to separately manufacture the swelling gauge 50 and the cell pressure plate 30 , and then couple the swelling gauge 50 to the cell pressure plate 30 by a screw fastening method or the like.
[49]
The side plates 23 and 24 are further provided with a gauge hole H1 allowing the swelling gauge 50 to pass therethrough. Therefore, the swelling gauge 50 is pushed out of the module housing 20 through the gauge holes H1 formed in the side plates 23 and 24 when the battery cells 11 are swollen as shown in FIG. 5 . can come out
[50]
At this time, the swelling amount of the battery cells 11 may be determined by measuring the length of the tip of the gauge hole H1 protruding out of the module housing 20 based on the gauge hole H1 . A scale 51 may be displayed on the swelling gauge 50 so that information on the swelling amount can be more easily understood.
[51]
The swelling gauge 50 of this embodiment is located at the exact center of the cell pressure plate 30 . This is in consideration of the expansion of the central portion of the battery cell 11 most convexly. That is, the center of the cell pressure plate 30 is the place most affected by the expansion of the battery cells 11 , and by arranging the swelling gauge 50 there, the amount of swelling of the battery cells 11 is most accurately measured. can do.
[52]
On the other hand, the leaf spring 40 is also provided with a plate hole (H2) that allows the passage of the swelling gauge 50 in the center. As a result, not only can the collision of the swelling gauge 50 and the leaf spring 40 be avoided when the battery cells 11 are swollen, but the leaf spring 40 can be hung on the swelling gauge 50, so that the cell pressure plate ( 30) and the center of the leaf spring 40 are conveniently placed in contact with each other.
[53]
To elaborate on this, as a way to avoid the collision between the swelling gauge 50 and the leaf spring 40, for example, two or more leaf springs 40 are used to the left relative to the swelling gauge 50, It is also possible to divide the arrangement on the right side. However, it may be most effective to use one leaf spring 40 and provide the plate hole H2 for the following reasons.
[54]
The leaf spring 40 is provided to have a width smaller than the width (Z-axis direction) of the cell pressure plate 30 and the side plates 23 and 24 in consideration of deformation during swelling of the battery cell 11 . For this reason, there is a problem in that the leaf spring 40 must be spaced apart from the bottom plate 22 by a predetermined height in order to match the centers of the leaf spring 40 and the cell pressure plate 30 . However, this problem is simply solved by drilling a plate hole in the plate spring 40 and suspending the plate spring 40 in the swelling gauge 50 as in the present embodiment. In addition, the use of one large leaf spring 40 may be more effective than the case of using several small leaf springs 40 to uniformly absorb the expansion force of the battery cells 11 and easier to install.
[55]
Next, a method of using the swelling gauge 50 will be briefly described as follows.
[56]
First, whether the battery cells 11 inside the battery module 1 are in a swelling state can be easily determined by looking at whether the tip of the swelling gauge 50 protrudes from the side plates 23 and 24 of the module housing 20 . is understood
[57]
Furthermore, if you want to know more precisely the amount of swelling of the battery cells 11 , you may check the scale of the swelling gauge 50 . That is, the length of the tip of the swelling gauge 50 protruding out of the gauge hole H1 of the side plates 23 and 24 means the swelling amount of the battery cells 11 . For example, a specific point of the scale of the swelling gauge 50 is marked in red, and if this specific point is outside the gauge hole H1, it is determined as a dangerous state and the user can take necessary measures in advance.
[58]
6 is an exploded perspective view of the cell pressure plate 30 , the buffer member 40 , and the side plate 23 according to another embodiment of the present invention.
[59]
Next, an installation structure of the swelling gauges 50a to 50c of the battery module 1 according to another embodiment of the present invention will be described with reference to FIG. 6 . The same reference numerals as in the above-described embodiment denote the same members, and duplicate descriptions of the same members will be omitted, and differences from the above-described embodiments will be mainly described.
[60]
In the above embodiment, the swelling gauge 50 is one at the center of the cell pressure plate 30, but the swelling gauges 50a to 50c according to this embodiment are plural, that is, as shown in FIG. 6 , A first swelling gauge 50a positioned at the exact center of the cell pressure plate 30, a second swelling gauge 50b and a third swelling gauge provided in both edge regions along the longitudinal direction of the cell pressure plate 30 (50c).
[61]
In addition, the gauge holes H1a to H1c of the side plate 23 and the plate holes H2a to H2c of the leaf spring 40 are also provided three each corresponding to the three swelling gauges 50a to 50c.
[62]
In the case of the above-described embodiment, if it is possible to measure only the amount of swelling in the central portion where the expansion of the battery cells 11 is most severe, the present embodiment additionally increases the amount of swelling in both edge regions of the battery cells 11 . can figure out In addition, it may be possible to determine how the expansion of the battery cells 11 is for each region.
[63]
In addition, the fixability of the leaf spring 40 to the cell pressure plate 30 may be improved. Since the leaf spring 40 can be hung by inserting it into the three swelling gauges 50a to 50c, it is possible to prevent the leaf spring 40 from rotating or twisting left and right based on the first swelling gauge 50a in the center. have.
[64]
As described above, in the battery module 1 according to an embodiment of the present invention, the swelling gauge 50 is configured so that anyone can simply check the swelling state of the battery cells 11 and take necessary measures. . This can be of great help in the safe use of the battery module 1 .
[65]
Meanwhile, a battery pack (not shown) according to an embodiment of the present invention includes one or more of the above-described battery modules 1 . In the battery pack, in addition to the battery module 1, a case for accommodating the battery module 1 (not shown), various devices (not shown) for controlling the charging and discharging of the battery module 1, for example, BMS (Battery Management) System), a current sensor, a fuse, and the like may be further included.
[66]
Of course, the battery module 1 or the battery pack may be applied to a vehicle such as an electric vehicle or a hybrid vehicle, an electric power storage device (ESS), and other electric devices using a secondary battery as an energy source.
[67]
As described above, although the present invention has been described with reference to limited embodiments and drawings, the present invention is not limited thereto, and the technical idea of ​​the present invention and the following by those of ordinary skill in the art to which the present invention pertains. Of course, various modifications and variations are possible within the scope of equivalents of the claims to be described.
[68]
Meanwhile, although terms indicating directions such as up, down, left, and right are used in the present specification, these terms are only for convenience of description, and may vary depending on the location of the target object or the location of the observer. It is apparent to those skilled in the art of
Claims
[Claim 1]
A battery module capable of intuitively checking the amount of swelling of battery cells accommodated in the module housing, at least one of both sides along the longitudinal direction of a cell stack accommodated in the module housing and formed by stacking the battery cells on at least one side a cell platen disposed to face; and a swelling gauge provided to protrude from the surface of the cell pressure plate, wherein the swelling gauge is discharged to the outside of the module housing through a gauge hole formed in the module housing when the battery cells are swollen. A battery module, characterized in that it is pushed out.
[Claim 2]
The battery module according to claim 1, wherein a buffer member is further interposed between the cell pressure plate and the module housing.
[Claim 3]
The battery module according to claim 2, wherein the buffer member is a leaf spring.
[Claim 4]
The battery module according to claim 3, wherein the leaf spring has at least one curved surface, one surface of which is in contact with the surface of the cell pressure plate, and the other surface of which is in contact with the surface of the module housing.
[Claim 5]
The battery module according to claim 3, wherein the leaf spring has a plate hole through which the swelling gauge passes, and is disposed in contact with the cell pressure plate while being suspended from the swelling gauge.
[Claim 6]
The battery module according to claim 1, wherein the swelling gauge is located in the center of the cell pressure plate.
[Claim 7]
According to claim 6, wherein the swelling gauge, A first swelling gauge located in the center of the cell pressure plate; and a second swelling gauge and a third swelling gauge provided on both edge regions along the longitudinal direction of the cell pressure plate.
[Claim 8]
According to claim 1, wherein the module housing, a top plate disposed on the top of the cell stack, a bottom plate disposed under the cell stack, the gauge hole, and each of the side surfaces of the cell stack A battery module, characterized in that the pair of side plates to be arranged are formed by assembling each other.
[Claim 9]
9. The method of claim 8, wherein the top plate and the bottom plate include bent portions provided by bending both edge regions in a longitudinal direction, and the pair of side plates includes a step portion provided with both edge regions in a longitudinal direction to be stepped. The battery module, characterized in that the step portion is shape-fitted to the inside of the bent portion.
[Claim 10]
10. A battery pack comprising the battery module according to any one of claims 1 to 9.