KR100649239B1 - Secondary battery module - Google Patents

Abstract

Provided is a secondary battery module using connection rods for fixing the whole battery module, which prevents the connection rods from pivoting to set a uniform coupling pressure in each connection rod and to support unit cells stably. The secondary battery module comprises: a plurality of unit cells(11) stacked successively; end plates(20) which are disposed outside of each unit cell and having a through-hole at the edges; and connection rods(30) inserted to the through holes to connect the end plates with each other, wherein the connection rod has a sectional structure with a non-uniform distance between the center and the outer circumferential surface.

Description

Secondary Battery Module {SECONDARY BATTERY MODULE}

1 is a perspective view illustrating a rechargeable battery module according to a first exemplary embodiment of the present invention.

2 is a partial perspective view showing an end plate in a first embodiment of the present invention.

3 is a perspective view showing a connecting rod according to a second embodiment of the present invention.

4 (a) to 4 (e) are cross-sectional views showing connection rods according to a first embodiment of the present invention and modifications thereof.

The present invention relates to a secondary battery module. More particularly, the present invention relates to a secondary battery module having an improved structure for supporting unit cells.

A secondary battery is a battery that can be charged and discharged unlike a primary battery that is not rechargeable. Such secondary batteries are used in portable electronic devices such as mobile phones, laptop computers, and camcorders in the case of low-capacity batteries in which one battery cell is packed in a pack form, and in the case of large-capacity batteries in units of battery packs in which dozens of battery cells are connected. It is widely used as a power source for driving motors of hybrid electric vehicles.

The secondary battery is manufactured in various shapes, and typical shapes include cylindrical shapes and square shapes.

Recently, a high output secondary battery using a high energy density nonaqueous electrolyte has been developed, and the high output secondary battery connects a plurality of batteries in series so as to be used for driving a motor such as an electric vehicle requiring a large power. It consists of a large capacity secondary battery.

In addition, one large-capacity secondary battery (hereinafter referred to as a battery module for convenience of description throughout) is composed of a plurality of secondary batteries (hereinafter referred to as unit cells for convenience of explanation throughout) in series.

Each of the unit cells includes a case having an electrode group having a positive electrode and a negative electrode interposed between the separator and a space in which the electrode group is embedded, a cap plate coupled to the case to seal the cap plate, and penetrating the cap plate And a positive electrode terminal and a negative electrode terminal which protrude and are electrically connected to the current collectors of the positive and negative electrodes provided in the electrode group.

In addition, each unit cell is typically arranged in such a way that the positive terminal and the negative terminal protruding to the top of the cap assembly alternately with the positive terminal and the negative terminal of the neighboring unit cell in the case of a rectangular battery, and between the threaded positive terminal and the negative terminal. The conductor is connected to and installed through a nut to form a battery module.

In this case, the battery module electrically connects a plurality of unit cells, and has a structure in which a plurality of unit cells are fastened to one battery module in order to secure stability of the battery module.

That is, end plates are respectively disposed at the outermost sides of the unit cells arranged in a row, and four connecting bars are installed at the end plates so that the end plates closely contact the inside of the unit cells. A nut is fastened to the rod so that the battery module is integrally fixed.

At this time, the connection rod rotates together with the nut in the process of fastening the nut to the connection rod, there is a problem that the fastening failure occurs.

In particular, when a plurality of connecting rods are installed in the end plate, the fastening pressure transmitted through the connecting rods needs to be set constant so that a uniform force can be applied to each connecting rod. However, if the connecting rod rotates together with the nut in the process of fastening the nut to the connecting rod, the connecting pressure of the connecting rod cannot be set uniformly.

In this way, if the fastening pressure of each connection rod is not set uniformly, excessive force is applied to one side of the connection rod, causing a problem that the connection rod is broken or the end plate is deformed.

Therefore, the present invention has been made to solve the above problems, an object of the present invention to provide a secondary battery module that can easily set the fastening pressure by preventing the rotation of the connecting rod.

In order to achieve the above object, the battery module according to the present invention includes a connecting rod including a cross section whose distance from the center to the outer circumference is not uniform.

To this end, the battery module of the present invention includes a plurality of unit cells that are stacked and arranged outside the unit cells, and end plates having through holes formed at edges thereof, and connecting rods inserted into the through holes to connect end plates. The connecting rod may include a cross section having a non-uniform distance from the center to an outer circumference, and the through hole may include a cross-sectional shape corresponding to the cross section of the connecting rod.

And the connecting rod has a long elongated rod portion that can be inserted from the through hole of one end plate to the through hole of the other end plate, and a head having a large cross section so that the rod can be supported by the end plate when inserted into the through hole. And a fastening threaded to allow the nut to be coupled to the opposite side of the head.

The head may be formed to have a circular cross section.

The through hole may be formed with a step, and the head may be inserted into the stepped step, and the rod may be inserted into the through hole.

The connecting rod may have a structure having at least one corner on an outer circumferential surface thereof. In the present invention, the edge refers to the edge of light, and is defined as a concept including not only the edge where the plane meets the plane but also the edge where the plane meets the curved surface.

In addition, the connection rod may be formed with at least one planar portion on the outer peripheral surface.

And the fastening portion may be a thread formed on the entire outer circumferential surface, or the thread may be formed only in the corner portion.

The connecting rod may be made of a rod having a polygonal cross section such as triangle, square, pentagon, or hexagon. The connecting rod may also consist of a rod having an elliptical cross section.

In addition, the secondary battery module is an energy source for driving a motor of the device in a device that operates by using a motor such as a hybrid electric vehicle (HEV), an electric vehicle (EV), a wireless cleaner, an electric bicycle, an electric scooter, and the like. Can be used as

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a perspective view illustrating a battery module according to a first embodiment of the present invention.

Referring to the drawings described above, the battery module according to the present embodiment includes a plurality of unit cells 11 stacked and arranged between the unit cells 11, and battery partition walls 12 that form a flow path for a heat transfer medium. ), An end plate 20 installed at both ends of the unit cells 11 so as to press the unit cells 11 inward, and a connection rod 30 connecting the end plates 20. It includes.

The end plate 20 includes a protrusion 21 protruding to the outside of the unit cell 11, and through holes 24 and 25 are formed to allow the connection rod 30 to be inserted into the protrusion 21. do.

And the connecting rod 30 is formed to have a large cross-sectional area at one end of the rod portion 31 and the one end of the rod portion 31 connecting the other protrusion 21 in one protrusion 21, the head portion fixed to the end plate (32), and a fastening portion (33) screwed on the outer circumferential surface so that the nut (34) can be engaged at the other end of the rod portion (31).

Here, the head 32 has a circular cross section. When the cross section of the head 32 is formed in a square shape, when the unit cell 11 expands and presses the end plate 20, stress concentration occurs at the corners of the square, causing the connection rod 30 to be broken. Can be.

In addition, the fastening part 33 is formed to protrude from an opposite end of the rod part 31 in which the head part 32 is installed, and has a structure in which the entire outer peripheral surface is screwed.

The rod 31 has a cross-sectional shape including portions having different distances from the center to the outer periphery. In FIG. 1, the bar part 31 is illustrated as a rectangular bar, but the shape of the bar part 31 is not limited thereto. Accordingly, the rod part 31 may have a polygonal cross-sectional structure having at least one flat part on an outer circumferential surface such as a triangle, a square, a pentagon, a hexagon, and the like as shown in FIG. 4.

In addition, the rod part 31 may be formed in a cross-sectional structure including a curved surface such as an oval in addition to the polygon.

As shown in FIG. 2, the through hole 24 formed in one end plate 20 in contact with the head 32 includes a stepped portion 24a and a hole 24b formed of a through hole. do. And the through-hole 25 formed in the other end plate 20 in contact with the nut 34 is made of a cross-section of a single structure without being stepped.

 The stepped portion 24a is formed in a circular cross section so that the head portion 32 of the connecting rod 30 can be inserted, and the hole portion 24b is formed of the rod portion 31 so that the rod portion 31 can be inserted therein. It has a structure corresponding to the cross-sectional shape.

Therefore, when the connecting rod 30 according to the present embodiment is inserted into the through hole 24, the head 32 is fitted into the stepped portion 24a, and the rod portion 31 is attached to the one side hole 24b. It is inserted into the through hole 25 formed in the other end plate.

In addition, the rod part 31 includes a cross section whose length is not uniform from the center to the outer circumference, and the hole part 24b and the through hole 25 are formed in a shape corresponding to the cross-sectional shape of the rod part 31 and thus the rod part. Support 31. Therefore, the rod part 31 can be prevented from rotating in the process of fastening the nut 34 to the fastening part 33 formed at the end of the bar part 31.

3 is a perspective view showing a connecting rod according to a second embodiment of the present invention.

The connecting rod 40 according to the present embodiment has a rod portion 41 fitted into the through hole of the end plate and a head portion 42 formed by a large cross-sectional area at one end of the rod portion and supported by the end plate, and a head portion. It is formed at the opposite end of 42, and includes a fastening portion 43 threaded so that the nut can be fastened.

The rod portion 41 according to the present embodiment is made of a hexagonal rod. However, this is exemplary and the present invention is not limited thereto. Therefore, the rod portion may be made of a rod having a polygonal cross-sectional shape, such as a triangle, a square.

And the fastening portion 43 may be made of a partially screwed structure. That is, the edge formed in the rod portion 41 and the portion adjacent to the edge may be screwed, and the edge and the edge may be formed without being threaded. Therefore, in this case, when the nut is coupled to the fastening portion 43, only the screwed portion comes into contact with the nut.

The secondary battery of the present invention is a device that operates by using a motor such as a hybrid electric vehicle (HEV), an electric vehicle (EV), a wireless cleaner, an electric bicycle, an electric scooter, and the like, and is used as an energy source for driving a motor of the device. Can be used.

Although the preferred embodiments of the present invention have been described above, the present invention is not limited thereto, and various modifications and changes can be made within the scope of the claims and the detailed description of the invention and the accompanying drawings. Naturally, it belongs to

As described above, according to the embodiment of the present invention, since the connecting rod can be prevented from rotating about the end plate, including a cross section whose distance from the center to the outer circumference is uneven, the nut can be easily fastened to the connecting rod. .

In addition, since the connecting rod is not rotated with respect to the end plate, an appropriate fastening pressure can be easily set for each connecting rod.

In addition, since the head of the connecting rod has a circular shape, stress concentration can be prevented even when the unit cell is expanded and the end plate is bent.

Claims (13)

A plurality of unit cells stacked; End plates disposed on the outside of the unit cells and having a through hole formed at an edge thereof; And A connecting rod inserted into the through hole to connect end plates; Including; The connecting rod is a secondary battery module having a cross-sectional structure of a uniform distance from the center to the outer peripheral surface. According to claim 1, The through hole has a cross-sectional shape corresponding to the cross section of the connecting rod. According to claim 1, The connection rod is a secondary battery module having at least one flat portion formed on the outer peripheral surface. According to claim 1, The connecting rod is a secondary battery module having at least one corner is formed on the outer peripheral surface. According to claim 1, The connection rod has a secondary battery module is formed at one end of the head portion consisting of an area larger than the cross section of the connection rod. The method of claim 5, The secondary battery module has a circular cross section. The method of claim 5, The through-hole is stepped to form a stepped portion is a secondary battery module that the head portion is fitted to the stepped portion. The method of claim 5, The connecting rod is a secondary battery module is formed with a screwed fastening portion is formed so that the nut can be fastened to the opposite end of the end formed with the head. The method of claim 8, The fastening part of the secondary battery module is the entire outer peripheral surface is threaded. The method of claim 8, Edges are formed on an outer circumferential surface of the connecting rod, and the fastening part is a secondary battery module in which a portion adjacent to the edge and the edge is screwed. According to claim 1, The connecting rod is a secondary battery module made of any one cross-sectional shape selected from the group consisting of triangular, square, pentagonal or hexagonal. According to claim 1, The connection rod is a secondary battery module having an elliptical cross section. According to claim 1, The secondary battery module is a secondary battery module for driving a motor.

Images