KR102488450B1 - Pouch type secondary battery to which a swelling prevention structure is applied and battery module including the same - Google Patents

Abstract

The present invention discloses a pouch type secondary battery having a hole in the center. A pouch-type secondary battery according to the present invention is a pouch-type secondary battery having an electrode assembly having a through hole formed vertically through the center and a pouch case in the form of a sheet for packaging the electrode assembly, in which an inlet and an outlet are opened. It may include a pipe part inserted into the through hole in the shape of an empty pipe and a bushing extending horizontally from an inlet and an outlet of the pipe part and having upper and lower ends contacting upper and lower surfaces of the electrode assembly. The bushing may have an adhesive layer on top and bottom to be heat-sealed to the inner surface of the pouch case.

Description

Pouch type secondary battery to which a swelling prevention structure is applied and battery module including the same}

The present invention relates to a pouch-type secondary battery and a battery module including the same, and more particularly, to a pouch-type secondary battery capable of suppressing a swelling phenomenon in a charging and discharging process, improving assembly convenience, and improving position fixation, and comprising the same It's about the battery module.

Currently commercially available secondary batteries include nickel cadmium batteries, nickel hydrogen batteries, nickel zinc batteries, and lithium secondary batteries. It is in the limelight because of its very low self-discharge rate and high energy density.

A lithium secondary battery includes an electrode assembly in which a positive electrode plate and a negative electrode plate coated with a positive electrode active material and a negative electrode active material are disposed with a separator interposed therebetween, and an exterior material that seals and houses the electrode assembly together with an electrolyte, that is, a battery case.

In general, lithium secondary batteries can 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, depending on the shape of an exterior material. Pouch-type secondary batteries are preferred because they are lightweight, have little possibility of electrolyte leakage, and can have flexibility in shape, so that they can implement secondary batteries of the same capacity with a smaller volume and mass than can-type secondary batteries.

However, since the pouch-type secondary battery has lower mechanical strength than the can-type secondary battery, securing safety is one of the most important issues that have recently emerged with respect to the pouch-type secondary battery. If the safety of the secondary battery is not secured, it may lead to accidents such as electric shock, fire, or explosion, as well as damage to the secondary battery, resulting in human life and property damage. Accordingly, various protection devices are being applied or attempted to secure the safety of the pouch-type secondary battery.

Nevertheless, it is still difficult to say that the safety of such a pouch type secondary battery has been completely secured. In particular, while the secondary battery is in use, internal pressure of the secondary battery increases and swelling may occur.

This swelling phenomenon may occur due to various causes such as overcharging, overdischarging, short circuit, leaving at high temperature, etc., which cause damage and performance reduction of the secondary battery, and may even cause explosion or ignition in severe cases.

In particular, as the application of secondary batteries has recently been expanded to medium-large devices such as automobiles and power storage devices, the size of secondary batteries is increasing day by day to improve capacity and output. However, as the size of the secondary battery increases, the volume change due to the swelling phenomenon may increase, and thus the damage may become more serious.

For example, as the size of the secondary battery increases, when a swelling phenomenon occurs, the reaction area of the electrode assembly decreases, and thus cell performance may deteriorate more severely. Moreover, in the case of a battery module used in a medium or large-sized device, it includes a plurality of secondary batteries in a packaged state. If a swelling phenomenon occurs in one secondary battery, the arrangement of other secondary batteries may be disturbed. Interconnection between them may be blocked, resulting in failure of the battery module. In addition, in the case of a battery module including a plurality of secondary cells, if the volume change of the secondary cells is severe, since the secondary cells must be placed in consideration of this, designing and manufacturing the battery module can be very difficult.

Korea Patent Registration No. 10-1419557 (2014.07.14) LG Chem Co., Ltd.

The present invention was devised to solve the above problems, and a pouch-type secondary battery configured to suppress the swelling phenomenon, and a surface pressure stronger than before in the central region of a cell laminate composed of the pouch-type secondary batteries It is an object of the present invention to provide a battery module capable of suppressing swelling of a cell stack by providing a.

Other objects and advantages of the present invention can be understood by the following description, and will be more clearly understood by the examples of the present invention. It will also be readily apparent that the objects and advantages of the present invention may be realized by means of the instrumentalities and combinations indicated in the claims.

A pouch-type secondary battery according to the present invention is a pouch-type secondary battery having an electrode assembly having a through-hole formed vertically through the center and a pouch case in the form of a sheet for packaging the electrode assembly,

A bushing having an upper end and a lower end disposed in contact with the upper and lower surfaces of the electrode assembly by being inserted into the through hole in the shape of a hollow pipe with open inlets and outlets and extending horizontally from the inlets and outlets. .

The bushing may further include adhesive layers that can be heat-sealed to the inner surface of the pouch case at the upper and lower ends.

The bushing includes: a first bushing assembly, a portion of which is inserted into the through hole at the bottom of the electrode assembly; and a second bushing assembly, a portion of which is inserted into the through hole and connected to the first bushing assembly at the top of the electrode assembly. can include

The bushing first assembly includes a first pipe portion inserted into the through hole and a first flange portion radially extending from a lower end of the first pipe portion and disposed in contact with a lower surface of the electrode assembly, The bushing second assembly is inserted into the through hole and is formed to radially extend from the upper end of the second pipe part and is fastened to the first pipe part by screwing, and is disposed in contact with the upper surface of the electrode assembly It may include a second flange portion to be.

The first and second flange parts may be formed in a plate-like shape having areas corresponding to the upper and lower surfaces of the electrode assembly and may be heat-sealed to the pouch case.

The first and second flange parts are formed in the form of an annular plate-shaped body having a diameter equal to or shorter than the short side length of the electrode assembly, and may be heat-sealed to the pouch case.

The pouch case may have an opening vertically communicating with the through hole.

The pouch case may include a notch line in an area vertically corresponding to the through hole, and an inner area of the notch line may be thicker toward an inner direction of the pouch case than other areas.

According to another aspect of the present invention, a battery module including the pouch-type secondary batteries described above, comprising: a cell stack formed by arranging the pouch-type secondary batteries in layers; an upper plate and a lower plate disposed in contact with upper and lower portions of the cell stack, respectively, with the cell stack interposed therebetween; and a plurality of fastening members integrally assembling the upper plate, the cell stack, and the lower plate, wherein one of the plurality of fastening members is connected to the cell stack through the bushings of the pouch-type secondary batteries. A battery module may be provided that penetrates the center and is fastened to the upper plate and the lower plate.

The upper plate and the lower plate may include an elastic pressing portion that elastically presses the cell stack.

The elastic pressing unit interconnects a pair of inclined sections and a point at which the inclined sections end, and includes a protruding section formed to protrude from the plate surface of the upper plate or the lower plate, and at least some of the protruding sections are stacked with the cells. The upper or lower surface of the sieve can be pressurized by contact support.

The elastic pressing unit may be provided one by one on left and right sides of the center of the cell stack.

According to another aspect of the present invention, a battery pack including at least one battery module may be provided.

According to one aspect of the present invention, a pouch-type secondary battery capable of suppressing swelling and having a hole in the center to pass a fastening member such as a shoulder bolt can be provided.

In addition, in the pouch-type secondary battery of the present invention, since the inside of the pouch case and the bushing hole through which the shoulder bolt passes are spatially separated, there is no fear of leakage of electrolyte and damage to the electrode assembly even when the shoulder bolt passes through the center.

According to another aspect of the present invention, a shoulder bolt can be vertically mounted in the central region of the upper plate, the cell stack composed of the pouch-type secondary batteries, and the lower plate, so that a stronger surface pressure than before is applied to the cell stack A battery module may be provided. Therefore, in the battery module of the present invention, swelling of the cell stack is suppressed, and thus performance degradation or appearance deformation may be prevented.

The following drawings attached to this specification illustrate preferred embodiments of the present invention, and together with the detailed description of the present invention serve to further understand the technical idea of the present invention, the present invention is the details described in such drawings should not be construed as limited to
1 is a perspective view of a pouch-type secondary battery according to an embodiment of the present invention.
FIG. 2 is a cross-sectional view taken along line II′ of FIG. 1 .
3 and 4 are cross-sectional views illustrating disassembled and coupled states of an electrode assembly and a bushing according to an embodiment of the present invention.
5 is an exploded perspective view of a bushing according to an embodiment of the present invention.
6 is an exploded and coupled perspective view of a bushing according to a modification of the bushing of FIG. 5;
7 is a perspective view of the electrode assembly to which the bushing of FIG. 6 is mounted.
8 is a plan view illustrating a modified example of the pouch case of FIG. 1 .
9 is a cross-sectional view along line II-II' of FIG. 8 .
10 is a perspective view showing a schematic configuration of a battery module according to an embodiment of the present invention.
11 is a partially exploded perspective view of the battery module of FIG. 10 .
FIG. 12 is a cross-sectional view taken along line III-III' of FIG. 10 .
13 is a view corresponding to FIG. 12 and is a cross-sectional view of a battery module according to another embodiment of the present invention.
14 is a perspective view schematically illustrating the configuration of the lower plate of FIG. 13;

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 this specification and claims should not be construed as being limited to the usual or dictionary meaning, and the inventor appropriately uses the concept of the term in order to explain his/her invention in the best way. It should be interpreted as a meaning and concept consistent with the technical idea of the present invention based on the principle that it can be defined.

Therefore, the embodiments described in this specification and the configurations shown in the drawings are only one of the most preferred embodiments of the present invention and do not represent all of the technical spirit of the present invention. It should be understood that there may be equivalents and variations.

1 is a perspective view of a pouch-type secondary battery according to an embodiment of the present invention, FIG. 2 is a cross-sectional view taken along II' of FIG. 1, and FIGS. 3 and 4 are an electrode assembly and a bushing according to an embodiment of the present invention. Cross-sectional views showing an exploded and coupled state of, and FIG. 5 is an exploded perspective view of a bushing according to an embodiment of the present invention.

Referring to FIGS. 1 and 2 , a pouch type secondary battery 10 according to the present invention includes an electrode assembly 20 , a pouch case 30 and a bushing 40 .

The electrode assembly 20 is configured such that one or more positive electrode plates and one or more negative electrode plates are disposed to face each other. That is, the positive electrode plate and the negative electrode plate are configured in a plate shape, and are arranged so that their wide surfaces face each other. In addition, the positive electrode plate and the negative electrode plate are configured to be separated from each other by a predetermined distance so as not to directly contact each other, and a separator may be interposed therebetween.

The positive electrode plate and the negative electrode plate are formed as a structure in which an active material slurry is applied to a current collector, and the slurry may be formed by stirring a granular active material, an auxiliary conductor, a binder, and a plasticizer in a state in which a solvent is added.

The positive electrode plate and the negative electrode plate may each have a positive electrode tab and a negative electrode tab on a non-coated portion on which an active material is not applied. In addition, the positive and negative tabs are connected to the positive lead 22a and the negative lead 22b, respectively, and the positive lead 22a and the negative lead 22b extend to the outside of the pouch case 30 to function as electrode terminals. do.

The pouch case 30 has a concave inner space, and an electrode assembly and electrolyte may be accommodated in this inner space. The pouch case 30 may be composed of an upper sheet 31 and a lower sheet 32 . The inner space of the upper sheet 31 and the lower sheet 32 may be sealed by sealing the edge lines of the electrode assembly 20 and the electrolyte solution in a state in which they are stored by thermal fusion.

On the other hand, the pouch type secondary battery 10 according to the present invention has a hole in the center. The hole may be provided in a vertically perforated form with respect to the wide surface of the pouch type secondary battery 10 .

Although described in detail later, the pouch-type secondary battery 10 according to the present invention is provided with the bushing 40 therein, so that the phenomenon of parts of the electrode assembly 20 can be suppressed. In addition, when manufacturing the cell stack 100 using the pouch-type secondary batteries 10, the shoulder bolt 410 can be safely inserted into the center of the pouch-type secondary battery 10 through the bushing 40, , Swelling of the cell stack 100 can be effectively suppressed by fastening to the upper and lower plates 200 and 300 to provide strong surface pressure to the cell stack 100 .

The structure of the pouch-type secondary battery 10 will be described in more detail.

The electrode assembly 20 according to the present invention has a through hole 21 formed vertically through the center.

To this end, the electrode assembly 20 is formed by alternately stacking a positive electrode plate, a separator film, and a negative electrode plate having a perforated center, or the electrode assembly 20 is made by stacking and folding the positive electrode plate, the separator film, and the negative electrode plate, and then , The through hole 21 may be formed by vertically drilling the central portion of the electrode assembly 20 . Here, the center of the electrode assembly 20, when viewed from above, may mean a point at which two imaginary straight lines that bisected the electrode assembly 20 horizontally and vertically cross each other.

However, the scope of the present invention should not be interpreted as being limited to the need for the through hole 21 to be formed in the center of the electrode assembly 20. One or more through holes 21 may be formed within a certain range based on the center of the electrode assembly 20 as needed.

The bushing 40 is inserted vertically into the through hole 21 to be mounted on the electrode assembly 20, and supports and presses the electrode assembly 20, and a shoulder bolt 410, which will be described later, safely secures the electrode assembly 20. It plays a role in allowing passage.

That is, as shown in FIG. 2, the upper and lower ends of the bushing 40 are in close contact with the upper and lower surfaces of the electrode assembly 20, and the portion connecting the upper and lower ends of the bushing 40 has an inlet and an outlet. It may be provided in the shape of an open hollow pipe and vertically inserted into the through hole 21 . And the upper and lower ends of the bushing 40 extend horizontally from the circumferences of the inlet and outlet, and an adhesive layer 47 may be provided on the surface thereof.

The adhesive layer 47 may be thermally fused to the inner surface of the pouch case 30 . Since the upper and lower ends of the bushing 40 are bonded to the pouch case 30 as described above, even if the pouch-type secondary battery 10 according to the present invention has a hole in its center, the electrolyte inside the pouch case 30 can escape to the outside. does not leak

More specifically, referring to FIGS. 3 to 5 , the bushing 40 according to the present embodiment is a bushing first assembly 41 in which a portion of the lower part of the electrode assembly 20 is fitted into the through hole 21 and a second bushing assembly 44, a portion of which is fitted into the through hole 21 at the top of the electrode assembly 20 and connected to the first bushing assembly 41.

And, the bushing first assembly 41 includes a first pipe part 42 and a first flange part 43, and the bushing second assembly 44 is vertically symmetrical with the bushing first assembly 41. It includes a second pipe portion 45 and a second flange portion 46.

The first pipe part 42 and the second pipe part 45 are configured to be inserted into the through hole 21 of the electrode assembly 20 to form a bushing hole P, and both ends are open and provided in a hollow pipe shape. can

In this embodiment, the first pipe portion 42 may be inserted into the through hole 21 vertically upward from the lower portion of the electrode assembly 20, and the second pipe portion 45 may be inserted from the upper portion of the electrode assembly 20. It may be inserted into the through hole 21 in a vertically downward direction and connected to the first pipe part 42 . As a connection method between the first pipe part 42 and the second pipe part 45, a screw coupling method may be employed.

For example, a female thread may be provided at one end of the first pipe portion 42 and a male thread may be provided at one end of the second pipe portion 45 . First, after inserting the first pipe part 42 into the electrode assembly 20 , the second pipe part 45 may be turned clockwise and inserted into the first pipe part 42 . According to such a screw coupling method, the first flange portion 43 and the second flange portion 46 corresponding to the upper and lower ends of the bushing 40 strongly rotate the electrode assembly 20 vertically by the tightening force of the male and female threads. put pressure on Accordingly, expansion of the positive electrode plate and the negative electrode plate constituting the electrode assembly 20 may be suppressed during the charging and discharging process.

Although not shown, as an alternative embodiment, the second pipe portion 45 may be omitted from the bushing second assembly 44, and a hole having a female thread may be provided at the center of the second flange portion 46. In addition, a male thread may be provided in the first pipe portion 42 of the first bushing assembly 41 so that one end of the first pipe portion 42 is fastened into the hole of the second flange portion 46. In this case, there is an advantage in that a step according to a difference in diameter between the first pipe part 42 and the second pipe part 45 in the through hole 21 shown in the enlarged view of FIG. 2 can be eliminated.

On the other hand, in this embodiment, although the screw coupling method is exemplified as a connection method between the first pipe portion 42 and the second pipe portion 45, for example, the second pipe portion 45 is connected in the first pipe portion 42 by an interference fit method. Any connection method may be employed as long as it does not form a gap between the first pipe portion 42 and the second pipe portion 45, such as by doing so.

The first flange portion 43 is a portion forming the lower end of the bushing 40 and is integrally formed with the first pipe portion 42 . As shown in FIG. 5, the first flange portion 43 extends radially (horizontally) around the lower end of the first pipe portion 42 and has an area corresponding to the lower surface of the electrode assembly 20. It may be provided in the form of a plate body. Therefore, when the first pipe portion 42 is completely inserted into the through hole 21 of the electrode assembly 20, the first flange portion 43 can be closely adhered to the lower surface of the electrode assembly 20.

The second flange portion 46 is a portion forming the upper end of the bushing 40 and is integrally formed with the second pipe portion 45 . The second flange extends radially (horizontally) around the upper end of the second pipe portion 45 and may be provided in a plate shape having an area corresponding to the upper surface of the electrode assembly 20 . Similarly to the first flange portion 43, when the second pipe portion 45 is fastened to the first pipe portion 42 and completely inserted into the through hole 21 of the electrode assembly 20, the second flange portion 46 also becomes an electrode. It can be in close contact with the upper surface of the assembly 20 correspondingly. The second flange portion 46 may be vertically opposed to the first flange portion 43 with the electrode assembly 20 interposed therebetween.

By forming the first flange portion 43 and the second flange portion 46 to correspond to the upper and lower surfaces of the electrode assembly 20, respectively, their surface pressure can act on the electrode assembly 20 in a wide range. Therefore, swelling of the pouch-type secondary battery 10 can be suppressed simply by mounting the bushing 40 according to the present embodiment to the electrode assembly 20 .

As the material of the bushing 40, for example, a material having excellent strength, insulation, and heat resistance, such as ceramic or carbon fiber reinforced plastic, may be employed.

On the other hand, the upper sheet 31 and the lower sheet 32 constituting the pouch case 30 are each provided with an opening 33 in the center. The opening 33 is formed at a position vertically communicating with the through hole 21 of the electrode assembly 20 .

That is, referring to FIG. 2 again, looking at the structure in which the electrode assembly 20 to which the bushing 40 is mounted is packaged in the pouch case 30, the edge lines of the upper sheet 31 and the lower sheet 32 are sealed. And, it can be seen that the lower surface of the upper sheet 31 and the upper surface of the second flange portion 46 are bonded and the upper surface of the lower sheet 32 is bonded to the lower surface of the first flange portion 43. And it can be seen that the opening 33 of the pouch case 30 communicates with the bushing hole P located in the through hole 21 .

Although not shown, a ring-shaped cap may be additionally installed around the opening 33 of the pouch case 30 so that the adhesive layer 47 of the bushing 40 is not exposed to the outside.

As described above, the pouch type secondary battery 10 of the present invention has a hole in the center so that the shoulder bolt 410 can pass through the center. In particular, since the bushing hole (P) is spatially separated from the inside of the pouch case 30, even if the shoulder bolt 410 is inserted into the center of the pouch-type secondary battery 10, damage or short circuit of the electrode assembly 20 is prevented. there is no fear that will happen

Next, a modified example of the bushing 40 according to the present embodiment will be briefly described with reference to FIGS. 6 and 7 .

6 is an exploded and coupled perspective view of a bushing 40a according to a modified example of the bushing 40 of FIG. 5, and FIG. 7 is a perspective view of the electrode assembly 20 to which the bushing 40a of FIG. 6 is mounted.

As shown in these figures, compared to the bushing 40 of the above-described embodiment, the bushing 40a according to the present modified example has a first flange portion 43a and a second flange portion 46a having an annular shape. It is provided in the form of a plate body. And, the diameter of the first flange part 43a and the second flange part 46a (centered on the first pipe part 42a and the second pipe part 45a) is the same as the length of the short side of the electrode assembly 20. or shorter.

For example, as shown in FIG. 7 , the electrode assembly 20 of this embodiment may be provided in a rectangular shape having a long side and a short side, and the first flange portion 43a and the second flange portion 46a have a diameter of Each of the short sides of the electrode assembly 20 is formed equal to or shorter than that.

For reference, unlike the present embodiment, when the electrode assembly 20 is provided in the form of a square having sides of the same length, the diameters of the first flange portion 43a and the second flange portion 46a are either side of the electrode assembly 20. It can be understood as being equal to or shorter than the length of.

Therefore, when the bushing 40a according to the present modified example is mounted on the electrode assembly 20, the first flange portion 43a and the second flange portion 46a have an area range of the upper and lower surfaces of the electrode assembly 20, respectively. will be located within For example, in the case of the bushing 40 according to the above-described embodiment, after inserting the first pipe part 42 into the through hole 21 of the electrode assembly 20, turning the second pipe part 45 clockwise to the first It is screwed to the pipe part 42, and the second flange part 46 has an angle with respect to the upper surface of the electrode assembly 20 according to the degree of rotation or tightening of the second pipe part 45 with respect to the first pipe part 42. If is misaligned, it may not be exactly matched to the upper surface of the electrode assembly 20, so that a part thereof may deviate from the range of the upper surface of the electrode assembly 20.

However, in the case of the bushing 40a according to the present modified example, the second flange portion 46a is always attached to the electrode assembly 20 regardless of the degree of rotation or tightening of the second pipe portion 45a with respect to the first pipe portion 42a. is located within the range of the upper surface of Therefore, according to this modified example, it is not necessary to check the alignment state of the electrode assembly 20 and the first and second flange parts 43a and 46a, and the second pipe part 45a is tightened more strongly into the first pipe part 42a. can be contracted.

For reference, the diameters of the first and second flange portions 43a and 46a are matched to the length of the short side of the electrode assembly 20 so that the surface pressure acting on the center of the electrode assembly 20 and its surroundings can be maximized. It may be desirable to form the first and second flange portions 43a and 46a.

In general, during swelling of the pouch-type secondary battery 10, the center portion of the electrode assembly 20 swells relatively more than the edge portion. From this point of view, the first and second flange portions 43a and 46a according to the modified example can be said to have a size sufficient to press the center of the electrode assembly 20 and its surroundings, so that the central portion of the electrode assembly 20 It can be effective in inhibiting swelling.

FIG. 8 is a plan view showing a modified example of the pouch case 30 of FIG. 1, and FIG. 9 is a cross-sectional view along line II-II' of FIG.

Next, a modified example of the pouch case 30 according to the above-described embodiment will be briefly described with reference to FIGS. 8 and 9 .

In the pouch case 30 of the above-described embodiment, an opening 33 communicating with the bushing hole P is formed in advance at the central portion. Therefore, after receiving the electrode assembly 20 to which the bushing 40 is mounted, and before heat-sealing the first and second flange portions 46 of the bushing 40 and the pouch case 30, the opening 33 and There is a difficulty in accurately matching the bushing hole (P). On the other hand, according to the modified example of the present invention, the above problem can be solved.

To this end, the pouch case 30 according to the present modified example is provided with a notch line 34 in an area corresponding vertically to the bushing hole P instead of the opening 33 in the central portion.

The notch line 34 may be understood as a line partially cut out in advance to easily remove a specific portion from the upper sheet 31 and the lower sheet 32 in a desired shape. According to the configuration of the notch line 34, if necessary, the inner region 35 of the notch line 34 is removed from the pouch case 30 by pressing the center of the pouch case 30 to open the opening 33 as in the above-described embodiment. ) can be formed.

In particular, referring to FIG. 9 , in the pouch case 30 according to the modified example, an inner region 35 of the notch line 34 is thicker toward the inside of the pouch case 30 than other regions.

When the electrode assembly 20 equipped with the bushing 40 is accommodated in the pouch case 30, the inner region 35 of the notch line 34 is formed between the first pipe part 42 and the second pipe part 45. can be embedded in Therefore, the opening 33 formed after removing the inner region 35 of the notch line 34 can communicate accurately with the bushing hole P inside the pouch case 30 vertically.

Hereinafter, a battery module constructed using the aforementioned pouch-type secondary batteries 10 will be described.

10 is a perspective view showing a schematic configuration of a battery module according to an embodiment of the present invention, FIG. 11 is a partially exploded perspective view of the battery module of FIG. 10, and FIG. 12 is a cross-sectional view along line III-III' of FIG.

Referring to these drawings, a battery module according to an embodiment of the present invention includes a cell stack 100, an upper plate 200, a lower plate 300, and a plurality of fastening members 410.

The cell stack 100 is an assembly of the pouch-type secondary batteries 10 described above, and may be implemented in a vertically stacked form. Although not shown, the cell stack 100 may further include a stacking frame (not shown) for stacking the pouch-type secondary batteries 10 .

The upper plate 200 is a plate-like structure that is placed in contact with the uppermost pouch-type secondary battery 10 and supports the cell stack 100 from the top. The lower plate 300 is a plate-like structure that is placed in contact with the lower portion of the pouch-type secondary battery 10 and supports the cell stack 100 from the lower portion.

The upper and lower plates 300 may be configured in the form of plates having a substantially large area, and may be positioned on the lower and upper portions of the cell stack 100 to cover the lower and upper portions of the cell stack 100, respectively. there is.

These upper and lower plates 300 provide mechanical support for the cell stack 100 and serve to protect the cell stack 100 from external shocks at the upper and lower portions of the cell stack 100. can do. In addition, when the cell stack 100 is swelling, it can absorb the expansion pressure of the cell stack 100 to prevent the appearance of the battery module from being deformed. Accordingly, the upper and lower plates 300 may be made of a metal material such as steel to secure rigidity.

In particular, according to the present invention, the cell stack 100 and the upper and lower plates 300 may be integrally assembled by a plurality of fastening members.

The fastening member 410 serves to integrally assemble the upper plate 200, the cell stack 100, and the lower plate 300 so that they are modularized in the form shown in FIG. 10. Here, as the fastening member 410, a shoulder bolt 410 having a screw at one end may be employed. One end of the shoulder bolt 410 may be fastened with a nut 420 or a cap nut.

In this embodiment, a total of five shoulder bolts 410 may be used. Among them, the four shoulder bolts 410 sequentially pass through the bolt passage holes 210 and 310 provided in the four corner regions of the lower plate 300 and the upper plate 200 while passing through the upper plate 200 and the lower plate 300. serves to connect

And the other shoulder bolt 410 is through the bolt passage holes 210 and 310 of the lower plate 300, the bushing holes P of the pouch type secondary batteries 10, and the bolt passage holes 210 and 310 of the upper plate 200. It serves to integrally connect the lower plate 300, the cell stack 100, and the upper plate 200 while passing in turn.

For example, when the cell stack 100 is manufactured using the large-area pouch-type secondary batteries 10 and only the corner regions of the upper plate 200 and the lower plate 300 are connected with shoulder bolts 410, the cell stack The surface pressure acting on the central region of 100 is relatively weak compared to the corner region, so that when the pouch-type secondary batteries 10 swell, the central regions of the upper and lower plates 300 do not withstand the expansion pressure and are bent outward. easy to lose

However, in the battery module according to the present invention, the shoulder bolts 410 pass through the center of the cell stack 100 and may also be fastened to the center regions of the upper plate 200 and the lower plate 300 . Therefore, the surface pressure acting on the central region of the cell stack 100 due to the tightening force between the shoulder bolts 410 and the nuts 420 located in the central regions of the upper plate 200 and the lower plate 300 is higher than before. By being reinforced, the swelling phenomenon of the cell stack 100 can be more effectively suppressed.

In addition, as shown in FIG. 11, when the pouch-type secondary batteries 10 are stacked, the pouch-type secondary batteries 10 are sequentially inserted into the shoulder bolts 410 and arranged so that the upper and lower sides of each pouch-type secondary battery 10 are stacked. Since left and right positions can be easily matched, stacking of the pouch-type secondary batteries 10 can be facilitated.

Next, a battery module according to another embodiment of the present invention will be described with reference to FIGS. 13 and 14 . Redundant descriptions with the foregoing embodiments will be omitted, and the differences will be mainly described.

FIG. 13 is a view corresponding to FIG. 12 and is a cross-sectional view of a battery module according to another embodiment of the present invention, and FIG. 14 is a perspective view schematically illustrating the configuration of the lower plate 300 of FIG. 13 .

In the battery module according to another embodiment of the present invention, elastic pressing parts 220 and 320 may be further provided on the lower surface of the upper plate 200 and the upper surface of the lower plate 300 .

The elastic pressing parts 220 and 320 contact the upper and lower surfaces of the cell stack 100, but press and support the cell stack 100 upward and downward to fix it.

13 and 14, the elastic pressing parts 220 and 320 interconnect a pair of inclined sections 222 and 322 and the point where the inclined sections 222 and 322 end, but the upper plate 200 or the lower plate 300 Protruding sections 221 and 321 formed to protrude from the plate surface are provided. At least some of the protruding sections 221 and 321 may contact and support the upper or lower surface of the cell stack 100 to press downward or upward. The elastic pressing parts 220 and 320 may be integrally manufactured with the upper plate 200 or the lower plate 300 by press working.

In addition, one elastic pressing unit according to the present embodiment may be provided on the left and right sides of the center of the cell stack 100 . By forming the elastic pressing portion in this way, it is possible to secure a space for fastening the shoulder bolts 410 to the central regions of the upper and lower plates 300, and to have elasticity in the left and right regions based on the central region of the cell stack 100, respectively. By providing the pressing parts 220 and 320, the surface pressure acting between the center area and the corner area can be further strengthened compared to the above-described embodiment.

Meanwhile, a battery pack (not shown) according to an embodiment of the present invention may include one or more battery modules described above.

In this case, the battery pack may further include, in addition to the battery module, a case for accommodating the battery module and various devices for controlling charging and discharging of the battery module, such as a battery management system (BMS), a current sensor, and a fuse. The battery pack according to the present invention may be applied to vehicles such as electric vehicles or hybrid vehicles.

As described above, although the present invention has been described by the limited embodiments and drawings, the present invention is not limited thereto, and the technical spirit of the present invention and the following by those skilled in the art to which the present invention belongs Of course, various modifications and variations are possible within the scope of equivalents of the claims to be described.

On the other hand, although terms indicating directions such as up, down, left, and right are used in this 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 of the present invention. is obvious to those skilled in the art.

10: pouch type secondary battery 20: electrode assembly
21: through hole 22a, 22b: electrode lead
30: pouch case 31: top sheet
32 lower seat 33 opening
34: notch line 40: bushing
41: bushing first assembly 42: first pipe part
43: first flange portion 44: bushing second assembly
45: second pipe part 46: second flange part
47: adhesive layer 100: cell laminate
200: upper plate 300: lower plate
220,320: elastic pressing part 400: fastening member

Claims (13)

A pouch-type secondary battery having an electrode assembly having a through-hole formed vertically through the center and a sheet-type pouch case for packaging the electrode assembly,
It is made of an insulating and heat-resistant material, is inserted into the through hole in the shape of a hollow pipe with open inlets and outlets, and extends horizontally from the inlets and outlets to make face-to-face contact with the upper and lower surfaces of the electrode assembly, respectively. It has a top and a bottom and includes a bushing disposed inside the pouch case,
A pouch-type secondary battery, characterized in that the upper and lower ends of the bushing have an adhesive layer on the surface and are adhered to the inner surface of the pouch case. According to claim 1,
The bushing,
A first bushing assembly having a portion at the bottom of the electrode assembly fitted into the through hole; and
A pouch-type secondary battery comprising a second assembly of bushings at an upper portion of the electrode assembly inserted into the through hole and connected to the first assembly of bushings. According to claim 2,
The bushing first assembly includes a first pipe portion inserted into the through hole and a first flange portion radially extending from the lower end of the first pipe portion and disposed in contact with the lower surface of the electrode assembly,
The bushing second assembly includes a second pipe portion inserted into the through hole and fastened to the first pipe portion by screwing, and extending radially around the upper end of the second pipe portion and contacting the upper surface of the electrode assembly. A pouch-type secondary battery comprising a second flange portion disposed thereon. According to claim 3,
The first and second flange parts are formed in a plate shape having areas corresponding to the upper and lower surfaces of the electrode assembly and are heat-sealed to the pouch case. According to claim 3,
The first and second flange parts are formed in the form of an annular plate-shaped body having a diameter equal to or shorter than the short side length of the electrode assembly and thermally fused to the pouch case. According to claim 1,
The pouch case is a pouch-type secondary battery, characterized in that it has an opening that communicates vertically with the through hole. According to claim 1,
The pouch case is provided with a notch line in an area vertically corresponding to the through hole, and an inner area of the notch line is thicker toward the inner direction of the pouch case than other areas. delete A battery module comprising the pouch-type secondary batteries according to any one of claims 1 to 7,
a cell stack formed by arranging the pouch-type secondary batteries in layers;
an upper plate and a lower plate disposed in contact with upper and lower portions of the cell stack, respectively, with the cell stack interposed therebetween; and
It includes a plurality of fastening members integrally assembling the upper plate, the cell stack, and the lower plate,
One of the plurality of fastening members passes through the center of the cell stack through the bushings of the pouch-type secondary batteries and is fastened to the upper plate and the lower plate. According to claim 9,
The upper plate and the lower plate,
The battery module, characterized in that it comprises an elastic pressing portion for elastically pressing the cell stack. According to claim 10,
The elastic pressing portion interconnects a pair of inclined sections and an end point of the inclined section, and has a protruding section formed to protrude from the plate surface of the upper plate or the lower plate,
Battery module, characterized in that at least some of the protruding sections contact and support the upper or lower surface of the cell stack and pressurize it. According to claim 11,
The battery module, characterized in that the elastic pressing portion is provided one by one on the left and right with respect to the center of the cell stack. A battery pack comprising at least one battery module according to claim 9 .

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