KR100709263B1 - Secondary battery module - Google Patents

Abstract

The present invention provides a plurality of unit cells, an end plate provided on the outermost side of the unit cells, a connecting member for connecting the end plates to support the unit cells so as to prevent deformation of the end plate, and the Provided is a secondary battery module including a buffer member installed on the connection member at a predetermined distance from an end of the connection member to support the end plate.

Secondary Battery Module, End Plate, Connecting Member, Shock Absorbing Member

Description

Secondary Battery Module {SECONDARY BATTERY MODULE}

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

2 is an exploded perspective view illustrating a connection member of a rechargeable battery module according to a first exemplary embodiment of the present invention.

3 is an exploded perspective view illustrating a connection member of a rechargeable battery module according to a second exemplary embodiment of the present invention.

The present invention relates to a secondary battery module configured by connecting a plurality of unit cells. More specifically, the present invention relates to a secondary battery module having an improved structure for supporting the secondary battery module.

In general, a secondary battery is a battery that can be charged and discharged unlike a primary battery that is not rechargeable. Low-capacity secondary batteries are used in portable electronic devices such as mobile phones, notebook computers, and camcorders, and large-capacity secondary batteries are widely used as power sources for driving motors in hybrid vehicles.

The secondary battery is manufactured in various shapes, and typical shapes of the secondary battery include cylindrical and rectangular shapes. A large capacity secondary battery in which a plurality of high output secondary batteries are connected in series is used for an apparatus requiring a large power, such as an electric vehicle.

As described above, 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 unit cell includes an electrode group in which a positive electrode and a negative electrode are positioned with a separator interposed therebetween, a case having a space in which the electrode group is embedded, and a case coupled to the case to be sealed and electrically connected to the electrode group. A cap assembly with terminals.

Each unit cell is usually arranged at regular intervals in the housing and connects the terminals of each unit cell to form a battery module.

Herein, the battery module has a structure in which a plurality of unit cells are fastened to one battery module for stability.

That is, a plurality of unit cells are stacked and arranged, two end plates are disposed on the outermost sides of the unit cells, and the end plates are supported by a plurality of rod-shaped connecting rods, and the unit cells are fastened to the battery module. In general, the connecting rod has a flange portion formed on one side and a threaded portion formed on the other side. The end plate is formed with a through hole into which the connecting rod is inserted. Therefore, the nut is fastened to the threaded portion of the connecting rod while the connecting rod is inserted into the through hole of the end plate so that the flange portion and the nut support the end plate, respectively.

When the battery module is used for a long time, a swelling phenomenon in which the inside of the unit battery is swollen may occur. In this case, the unit battery is expanded to press the end plate. In addition, the pressing force increases as the unit cell repeats charging and discharging, and a problem arises in that the end plate is deformed by the increased pressing force.

When bending deformation occurs in the end plate, the nut that fixes the connecting rod or the connecting rod to the end plate contacts the end plate non-uniformly, the stress is concentrated unevenly at the contact portion, and the part is concentrated at the portion where the stress concentrates. Deformed or serious cases have a problem of breaking.

In addition, when a stress above the yield point acts on the end plate and the end plate is bent due to plastic deformation, there is a permanently concentrated portion of stress and a greater risk of deformation or breakage of such portion.

In order to solve such a problem, if the connection rod or the end plate is made thick, the overall weight of the secondary battery module increases, causing the performance of the device in which the battery module is mounted.

In particular, in the case of a secondary battery for driving a motor used in a hybrid electric vehicle (HEV), an electric bicycle, an electric scooter, and the like, it is important to reduce the self-load of the battery in order to improve the performance of the devices. Increasing the thickness is an increase in the weight of the battery module, there is a problem that is difficult to apply for driving the motor is reduced the output to weight.

Accordingly, the present invention has been made to solve the above problems, it is an object of the present invention to provide a secondary battery module that can prevent the deformation of the end plate by improving the structure for supporting the end plate.

In order to achieve the above object, a battery module according to the present invention includes a plurality of unit cells, an end plate installed at an outermost side of the unit cells, a connection member connecting the end plates to support the unit cells, and And a buffer member installed on the connection member at a predetermined distance from an end of the connection member to support the end plate.

The buffer member may be formed of a rod member installed through the connection member.

In addition, a through hole is formed in the connection member, and the buffer member may be formed of a pin fitted into the through hole, and the pin may have a flange having a large cross-sectional area at one end thereof so as not to be separated from the through hole. have.

A flange portion is formed at one end of the connection member, and a screw processing portion may be formed at the other end to allow the nut to be fastened.

The shock absorbing member may be spaced apart from the flange by a predetermined distance. The nut may be fastened to the screw processing part, and the shock absorbing member may be spaced apart from the nut by a predetermined distance.

A plurality of shock absorbing members may be installed in the connecting member, and the plurality of shock absorbing members installed in the connecting member may be formed of shock absorbing members having different cross-sectional areas.

P1 the pressing force acting on the end plate when the connecting member is fastened to the end plate, P2 the pressing force acting on the end plate when the shock absorbing member is broken, and the pressing force acting on the end plate when the end plate is plastically deformed. In this case, P1 <P2 <P3 can be made.

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, an embodiment of the present invention will be described with reference to the accompanying drawings.

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

Referring to the drawings described above, the battery module according to the present exemplary embodiment is disposed between the plurality of unit cells 11 and the unit cells 11 to provide a plurality of battery partition walls 12 for providing a flow path of the heat transfer medium. It includes.

In the following embodiment, a case in which the unit battery 11 is formed in a square shape will be described. However, the present invention is not limited thereto, and the present invention may be applied to unit cells having various shapes such as a cylindrical shape.

Each unit cell 11 is formed of a secondary battery having a conventional structure in which a group of electrodes laminated in a case is disposed between a positive electrode and a negative electrode in a case to charge and discharge a predetermined amount of electricity.

Battery partition walls 12 are provided between the unit cells 11 to maintain a gap between the unit cells 11 and to distribute heat transfer medium between the unit cells 11.

A pair of end plates 28 for pressing the unit cells 11 inwardly are installed outside the stacked unit cells 11, and the end plates 28 are fixed to the end plates 30. The connecting member 20 is installed.

A plurality of through holes (not shown) are formed in the end plate 28, and a connecting member 20 supporting the end plates 30 is inserted in the through holes. The connecting member 20 is formed on the rod portion 21 and the flange portion 22 formed at one end of the rod portion 21, and the screw processing portion 23 formed at the other end of the rod portion 21 to which the nut is fastened. ). In this embodiment, four connecting members 20 are installed on the end plate 28 to fix the end plate 28. However, this is exemplary and the present invention is not limited thereto.

A through groove 26 is formed in the connecting member 20 spaced apart from the flange portion 22 by a predetermined distance, and the buffer member 25 having a rod shape is fitted into the through groove 26. The shock absorbing member 25 is preferably made of a pin, and the shock absorbing member 25 is spaced apart from the flange part 22 by a length in which the unit cells 11 arranged are pressed by the end plate 28 to be reduced. Can be installed.

In the present embodiment, the shock absorbing member 25 is illustrated as being spaced apart from the flange part 22 by a predetermined distance, but the present invention is not limited thereto, and the shock absorbing member 25 is opposite to the flange part 22. It may be installed spaced a predetermined distance from the nut 24 is installed in.

As shown in FIG. 2, the buffer member 25 is installed in a structure in which the buffer member 25 protrudes on both sides of the through groove 26 by passing through the through groove 26, and the buffer member 25 is It may be forced fit or interfit into the through groove 26.

The connecting member 20 is coupled to the end plate 28 in a state where the shock absorbing member 25 is fitted, and the connecting member 20 is inserted into the through holes formed in both end plates 28. The nut 24 is coupled to the screw machining portion 23 of the.

When the nut 24 is tightened, the end plate 28 comes into close contact with the unit cell 11 to press the unit cells 11 inward. At this time, one end plate 28 is fixed by the buffer member 25, the other end plate 28 is fixed by a nut 24.

On the other hand, when installing the end plate 28, a fastening pressure is applied to press the unit cells 11 inward, the strength of the buffer member 25 is made of a strength that can withstand this initial fastening pressure, the unit The swelling phenomenon occurs inside the battery 11 and the strength is set so that the unit cell 11 swells and breaks when the force for pressing the end plate 28 reaches a predetermined level.

Preferably, when the swelling phenomenon occurs inside the unit cell and the unit cells 11 expand, the force for pressurizing the end plate 28 increases and the end plate 30 is plastically deformed. When plastic deformation is applied, the strength of the shock absorbing member 25 can be set so that the shock absorbing member 25 breaks when an urging force smaller than the pushing force acting on the end plate acts on the end plate.

When the shock absorbing member 25 is installed at a predetermined distance from the flange portion 22, the shock absorbing portion A is formed between the shock absorbing member 25 and the flange portion 22. The buffer portion A refers to a space between the end plate and the flange portion. When the buffer portion is formed, the unit cell 11 swells due to a swelling phenomenon and the pressure applied to the end plate 28 increases. Before the plate 28 is deformed, the shock absorbing member 25 is first broken so that the end plate 28 is pushed into the flange portion 22 to reduce the pressing force acting on the end plate.

If four buffer members 25 are installed on the end plate 28 and one of the shock absorbing members 25 is broken first, even if the shock absorbing members 25 are not broken at the same time, stress is concentrated on the remaining shock absorbing members 25. Almost simultaneously, the remaining cushioning member 25 can also be broken. Therefore, when one of the shock absorbing members 25 is broken, the other shock absorbing members 25 are also broken at about the same time so that the end plate 28 is pushed to the flange portion 22.

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

Referring to the drawings described above, the connection member 30 according to the present embodiment includes a flange portion 32 formed at one end and a screw processing portion 37 formed at the opposite end of the flange portion 32. do.

Shock absorbing members 35 and 36 are installed at portions spaced apart from the flange portion 32 by a predetermined distance, and a plurality of shock absorbing members 35 and 36 are installed in the longitudinal direction of the connecting member 30. The shock absorbing members 35 and 36 are installed to fit into the through grooves 33 formed in the connecting member, and a plurality of shock absorbing members 35 and 36 having a cross-sectional area are installed. That is, the shock absorbing member 35 provided inside is made thinner and weaker than the shock absorbing member 36 provided outside, thereby forming a plurality of shock absorbing parts.

Therefore, even if the shock absorbing member 35 located inside breaks, the shock absorbing member 36 located outside supports the end plate 28 (shown in FIG. 1), and when the shock absorbing member 36 located outside breaks, the flange portion again. 32 may support end plate 28. In this way, the buffer portion is formed in multiple stages so that the pressing force acting on the end plate 28 can be reduced step by step.

That is, when a swelling phenomenon occurs inside the unit cell 11 and the volume of the unit cell 11 expands, the force acting on the shock absorbing member 35 increases to a certain level. As the end is broken, the end plate 28 is pushed outward. And when the end plate 28 is pushed outward, the force acting on the end plate 28 is reduced, the swelling phenomenon continues to occur and the force acting on the end plate 28 again increases the second cushioning member As the 36 is broken, the end plate 28 is pushed to the flange portion 32.

With this structure, the pressing force acting on the end plate 28 and the unit cell 11 can be reduced step by step, thereby increasing the stability of the battery module.

The battery module of the present invention is a device for operating by using a motor such as a HEV (hybrid electric vehicle), an EV (electric vehicle), a cordless cleaner, an electric bicycle, an electric scooter, and the like for driving energy of the motor of the device. Can be used as a circle.

In the above description of the preferred embodiment of the present invention, 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 the range of.

As described above, according to the present invention, when the buffer member is installed in the connecting member and the buffer member is formed between the buffer member and the flange portion, the swelling phenomenon causes the volume of the unit cell to expand, thereby increasing the force on the end plate. As it breaks, the end plate is pushed outward to reduce the stress on the end plate, thereby preventing the end plate from deforming.

In addition, since the shock absorbing member is formed in plural and broken in steps, it is possible to prevent excessive stress from acting on the unit cell and the end plate.

Claims (10)

A plurality of unit cells; An end plate installed at the outermost sides of the unit cells; A rod-shaped connecting member fitted to the end plates to support the unit cells; And A rod-shaped buffer member installed spaced apart from an end of the connecting member and fitted into the connecting member and protruding to an outer circumference of the connecting member to support the end plate; Secondary battery module comprising a. delete According to claim 1, The buffer member is a secondary battery module consisting of a pin that is fitted into the through hole formed in the connection member. According to claim 1, A secondary battery module having a flange portion formed at one end of the connection member, a screw processing portion is formed at the other end so that the nut can be fastened. The method of claim 4, wherein The buffer member is a secondary battery module is installed spaced apart from the flange at a predetermined distance. The method of claim 4, wherein A nut is fastened to the screw processing part and the shock absorbing member is installed at a predetermined distance from the nut. According to claim 1, A secondary battery module having a plurality of shock absorbing members are installed in the connection member. The method of claim 7, wherein The buffer members have different sizes of cross-sectional areas. According to claim 1, P1, the pressing force acting on the end plate when the connection member is fastened to the end plate; P2, the pressing force acting on the end plate when the buffer member is broken; If the pressing force acting on the end plate when the end plate is plastically deformed is P3, P1 <P2 <P3 Secondary battery module. According to claim 1, The secondary battery module is a secondary battery module for driving a motor.

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