KR20230063248A - Battery module - Google Patents

Abstract

The present invention relates to a battery module blocks a welding laser beam from penetrating inside and can effectively maintain a pre-assembled state for performing laser welding by forming a coupling groove unit on the bottom of an upper frame into which the upper end of a side frame is at least partially inserted, and can effectively prevent a joint unit between the upper frame and the side frame from opening or breaking due to external pressure and external pressure without a separate coupling means.

Description

Battery module {BATTERY MODULE}

The present invention relates to a battery module, and more particularly, to form a coupling groove into which an upper end of a side frame is at least partially inserted into a bottom surface of an upper frame to prevent a welding laser from penetrating into the inside and to perform laser welding at the same time. The present invention relates to a battery module capable of effectively maintaining a pre-assembled state for the purpose and effectively preventing a junction between an upper frame and a side frame from being cracked or damaged due to external pressure and external pressure without adding a separate coupling means.

With heightened interest in the environment, efforts to reduce carbon emissions are spreading worldwide. In order to reduce carbon emissions, production of conventional vehicles equipped with combustion engines powered by burning fossil fuels is continuously decreasing, while production of electric vehicles powered by electricity is continuously increasing.

Demand for a secondary battery, which is a means of storing electricity mounted on such an electric vehicle, is continuously increasing. On the other hand, in a situation where the use of personal mobile devices such as smart phones and tablet PCs has become commonplace, the demand for secondary batteries that supply electricity to mobile devices is also continuously increasing.

Due to such an increase in demand for secondary batteries, research and development on secondary batteries are being actively conducted.

At this time, in order to improve the capacity and efficiency of the secondary battery, there is an increasing demand for a battery pack having a multi-module structure in which battery modules in which a plurality of secondary batteries are connected in series/parallel are assembled.

When a battery pack is configured by connecting a plurality of battery cells in series/parallel, a battery module composed of at least one battery cell is configured, and other components are added using the at least one battery module to configure the battery pack. method is generally applied.

In constructing a frame that protects the inside of one battery module, a battery module formed of a U-frame structure capable of improving the quality of parts and increasing space utilization has been developed.

A battery module having such a U-frame structure is formed of a battery cell stack in which a plurality of battery cells are stacked, a bottom surface and both sides of the battery cell stack, and a lower frame of a U-shaped structure covering the lower surface and both sides of the battery cell stack, It may be configured to include an upper frame covering the upper surface of the battery cell stack.

In this regard, Korea Patent Publication No. 10-2021-0064715 (Prior Document 001) discloses a battery module having a structure of upper and lower frame contacts in a conventional battery module as shown in FIGS. 1 and 2 .

Referring to FIG. 1, the battery module of Prior Document 001 is formed of a battery cell 10 stack, a bottom surface and both sides, and a lower frame 20 covering the lower surface and both side surfaces of the battery cell stack, battery cell stack It was formed of an upper frame 30 covering the upper surface of the body and a pad 11 formed between the outermost battery cell and the lower frame 20 .

At this time, the lower frame 20 and the upper frame 30 are bonded through laser welding. As shown in the enlarged view of FIG. 2 , laser welding is performed between the lower frame 30 and the upper frame 20 during laser welding. In order to prevent passing through, a laser blocking structure may be provided.

The laser blocking structure may be achieved through a rib or a bent surface provided in a form that blocks the welding surface formed between the lower frame 30 and the upper frame 20 from the inside.

The junction structure and laser blocking structure of the battery module disclosed in Prior Document 001 effectively prevents the laser used during welding from passing through the lower frame 30 and the upper frame 20 to reach the battery cell 10 disposed therein. can block In addition, through this bonding structure, even when a certain level of external pressure acts, the lower frame 30 does not deform toward the battery cell 10 and can effectively protect the battery cell 10 .

However, when the internal pressure of the battery module increases due to overheating of the battery cell 10, the upper end of the lower frame 30 receives a force that spreads from the inside to the inside. It has a problem that the upper end of can not effectively cope with the force that spreads to the outside. That is, the battery module disclosed in Prior Document 001 has a structure in which a welded portion is easily damaged or deformed due to internal pressure.

Korean Patent Publication No. 10-2021-0064715

The present invention has been made to solve the problems of the prior art described above, by forming a coupling groove into which the upper end of the side frame is at least partially inserted on the lower surface of the upper frame, thereby blocking the penetration of the welding laser into the inside and at the same time A first object is to provide a battery module capable of effectively maintaining a pre-assembled state for performing laser welding.

In addition, a second object of the present invention is to provide a battery module that can effectively prevent cracking or cracking of the joint between the upper frame and the side frame due to external pressure and external pressure without adding a separate coupling means. to be

The objects of the present invention are not limited to the above-mentioned objects, and other objects and advantages of the present invention not mentioned above 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 battery module according to the present invention includes a battery cell laminate formed by stacking a plurality of battery cells; A bottom frame covering a lower portion of the battery cell stack; a pair of side frames integrally formed with the bottom frame and covering both side surfaces of the battery cell stack; and an upper frame covering an upper surface of the battery cell stack, wherein the bottom frame includes coupling grooves into which upper ends of the pair of side frames are at least partially inserted.

In addition, the coupling groove may be formed on a lower surface of the bottom frame facing the battery cell stack.

In addition, the coupling groove may extend linearly along the longitudinal direction of the upper ends of the pair of side frames.

In addition, an insertion portion inserted into the coupling groove may be provided at an upper end of the pair of side frames.

Also, a thickness of the insertion portion may be smaller than a thickness of the pair of side frames.

In addition, a stepped surface formed at an upper end of the pair of side frames may be provided at a lower position than the insertion part in the vertical direction.

In addition, a height of the insertion part from the stepped surface based on the vertical direction may be smaller than or equal to a depth of the coupling groove from the stepped surface.

Also, a width of the insertion portion may be smaller than or equal to a width of the coupling groove portion.

In addition, the stepped surface may come into surface contact with the lower surface of the upper frame.

In addition, the stepped surface and the lower surface of the upper frame may be coupled through laser welding.

The battery module according to the present invention forms a coupling groove into which the upper end of the side frame is at least partially inserted on the bottom surface of the upper frame to block penetration of the welding laser into the inside and at the same time to perform laser welding. It has an effect that can be effectively maintained.

In addition, the battery module according to the present invention has an effect of effectively preventing the junction between the upper frame and the side frame from being opened or damaged due to external pressure and external pressure without adding a separate coupling means.

In addition to the effects described above, specific effects of the present invention will be described together while explaining specific details for carrying out the present invention.

1 and 2 are cross-sectional views showing a structure of coupling between an upper frame and a lower frame in a conventional battery module.
3 is an exploded perspective view showing a battery module according to an embodiment of the present invention.
Figure 4 is a perspective view of the upper frame shown in Figure 3;
Figure 5 is a perspective view of the lower frame shown in Figure 3;
6 is a partially enlarged view of a side frame constituting the lower frame shown in FIG. 5.
7 is a cross-sectional view for explaining a coupling structure between a side frame and an upper frame.

The above objects, features and advantages will be described later in detail with reference to the accompanying drawings, and accordingly, those skilled in the art to which the present invention belongs will be able to easily implement the technical spirit of the present invention. In describing the present invention, if it is determined that the detailed description of the known technology related to the present invention may unnecessarily obscure the subject matter of the present invention, the detailed description will be omitted. Hereinafter, preferred embodiments according to the present invention will be described in detail with reference to the accompanying drawings. In the drawings, the same reference numerals are used to indicate the same or similar components.

Although first, second, etc. are used to describe various components, these components are not limited by these terms, of course. These terms are only used to distinguish one component from another component, and unless otherwise stated, the first component may be the second component, of course.

Throughout the specification, unless otherwise stated, each element may be singular or plural.

Hereinafter, the arrangement of an arbitrary element on the "upper (or lower)" or "upper (or lower)" of a component means that an arbitrary element is placed in contact with the upper (or lower) surface of the component. In addition, it may mean that other components may be interposed between the component and any component disposed on (or under) the component.

In addition, when a component is described as "connected", "coupled" or "connected" to another component, the components may be directly connected or connected to each other, but other components may be "interposed" between each component. ", or each component may be "connected", "coupled" or "connected" through other components.

Singular expressions used herein include plural expressions unless the context clearly dictates otherwise. In this application, terms such as "consisting of" or "comprising" should not be construed as necessarily including all of the various components or steps described in the specification, and some of the components or some of the steps It should be construed that it may not be included, or may further include additional components or steps.

Also, singular expressions used in this specification include plural expressions unless the context clearly indicates otherwise. In this application, terms such as "consisting of" or "comprising" should not be construed as necessarily including all of the various components or steps described in the specification, and some of the components or some of the steps It should be construed that it may not be included, or may further include additional components or steps.

Throughout the specification, when "A and/or B" is used, this means A, B or A and B unless otherwise specified, and when used as "C to D", this means unless otherwise specified As long as there is no, it means C or more and D or less.

Hereinafter, the present invention will be described with reference to drawings showing the configuration of a battery module 1 according to an embodiment of the present invention.

[Overall structure of battery module]

Hereinafter, the overall structure of the battery module 1 according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

3 is an exploded perspective view of a battery module 1 according to an embodiment of the present invention.

Referring to FIG. 3, the battery module 1 according to an embodiment of the present invention is configured in a state in which a plurality of battery cells are accommodated inside a case or housing composed of a lower frame 200 and an upper frame 300. can

More specifically, a plurality of battery cells may be closely arranged in a stacked state to form the battery cell stack 100 .

A lower frame 200 having a structure surrounding the lower surface and both side surfaces of the battery cell stack 100 to accommodate the battery cell stack 100 therein so as to configure the case or housing of the battery module 1, An upper frame 300 disposed on the upper surface side of the battery cell stack 100, and a pair of end frames 400 disposed to face the electrode leads of the battery cell stack 100 may be included.

As shown, the lower frame 200 may include a bottom frame 220 constituting a bottom surface and a pair of side frames 210 constituting two side walls. Illustratively, the bottom frame 220 and the pair of side frames 210 may be integrally formed by press-working a metal plate having a predetermined strength.

Pouch-type battery cells may be used as the plurality of battery cells, and bidirectional battery cells in which positive and negative leads protrude in opposite directions may be used.

A plurality of battery cells may be electrically connected to electrode leads using a bus bar or the like so that they are connected in series or parallel according to the desired output and capacity of the battery module 1 . Depending on the specifications of the applied product, the battery cell stack 100 may further include a cartridge for accommodating the battery cells, a buffer member, or a cooling means.

The end frame 400 may be mounted on the main frame together with the battery cell stack in a state connected to the battery cell stack, or the battery cell stack is mounted on the main frame and the end frame is coupled to the main frame. Frame 400 may be coupled.

The upper frame 300 serves to cover the upper surface of the battery cell stack 100 and, like the lower frame 200, may be formed of a metal plate having a predetermined strength.

The upper frame 300 may be assembled to the lower frame 200 by being coupled to the upper ends 211 of the pair of side frames 210 .

The bottom surface 301 of the upper frame 300 and the upper part 211 of the side frame 210 may be coupled through laser welding (L).

As shown in FIG. 4 , the lower surface 301 of the upper frame 300 may be provided with a coupling groove 310 into which the upper end 211 of the side frame 210 may be at least partially inserted.

The coupling groove 310 may be formed to have a shape corresponding to the shape of the upper end 211 of the side frame 210 into which it is inserted. If is extended linearly along the front-rear direction, corresponding to this, the coupling groove 310 may be extended linearly along the front-rear direction.

As shown in FIG. 6 , an insertion portion 213 inserted into the coupling groove 310 may be provided at the upper end 211 of the side frame 210 .

As in the illustrated embodiment, the insertion portion 213 may be illustratively formed by at least partially cutting the upper end 211 of the side frame 210 . Preferably, the insertion portion 213 may be formed by linearly cutting a portion of the upper end portion 211 close to the outer surface of the side frame 210 along the front-back direction to form the stepped surface 212 .

Accordingly, the thickness of the insertion portion 213 may be smaller than that of the side frame 210 .

As will be described later, the stepped surface 212 formed lower in the vertical direction than the height of the upper end of the insertion portion 213 through cutting directly contacts the bottom surface 301 of the upper frame 300.

Preferably, in order to maximize the contact area, the stepped surface 212 is configured to make surface contact with the bottom surface 301 of the upper frame 300, and the stepped surface 212 and the bottom surface 301 of the upper frame 300 may be configured to have shapes corresponding to each other.

Illustratively, in order to maximize the surface contact area, as shown in FIG. 7, the width W3 of the stepped surface 212 based on the left and right directions is formed to be larger than the width W2 of the insertion portion 213. can

On the other hand, as will be described later, laser welding (L) is performed between the stepped surface 212 and the bottom surface 301 of the upper frame 300 that are in surface contact, and the side frame 210 and the upper part are formed through the laser welding (L). Coupling between the frames 300 may proceed.

[Coupling structure and laser penetration blocking structure]

Hereinafter, a coupling structure between the side frame 210 and the upper frame 300 of the battery module 1 according to an embodiment of the present invention will be described in detail with reference to FIG. 7 .

FIG. 7 illustratively shows a coupling structure between a left side frame and an upper frame 300 among a pair of side frames 210 . Although not shown, the same coupling structure may be applied between the right side frame and the upper frame 300 . A description of overlapping contents of the coupling structure of the right side frame and the upper frame 300 will be omitted.

As shown in FIG. 7 , the insertion part 213 provided inside the upper end of the side frame 210 may be inserted into the coupling groove 310 formed on the lower surface 301 of the upper frame 300. .

As shown, a height H2 at which the insertion portion 213 protrudes from the stepped surface 212 in the vertical direction may be smaller than or equal to the depth H1 of the coupling groove 310 .

Therefore, even when the insertion part 213 is fully inserted into the coupling groove 310, surface contact between the stepped surface 212 and the bottom surface 301 of the upper frame 300 can be maintained.

In addition, the width W2 of the insertion part 213 is formed smaller than the width W1 of the coupling groove 310 based on the left and right directions so that the insertion part 213 can be easily inserted into the coupling groove 310. It can be.

In this way, when the insertion part 213 is inserted into the coupling groove 310 and the bottom surface 301 of the upper frame 300 and the stepped surface 212 come into surface contact, the upper frame 300 and the side Temporary assembly between the frames 210 may be completed.

This state is referred to as a temporary assembly state because the upper frame 300 and the side frame 210 are not fastened or fixed to each other.

In this way, when the temporary assembly between the upper frame 300 and the side frame 210 is completed, the next step is between the lower surface 301 of the upper frame 300 and the stepped surface 212 of the side frame 210 in a surface contact state. Laser welding (L) may proceed.

As shown, the laser welding (L) is performed in a manner in which a laser beam is irradiated from the outside of the battery module 1 to the lower surface 301 of the upper frame 300 and the stepped surface 212 of the side frame 210. can

Therefore, there is a possibility that the laser beam for welding penetrates between the lower surface 301 of the upper frame 300 and the stepped surface 212 of the side frame 210, but as shown, the laser beam penetrates the insertion part 213. Since the laser beam extends in a direction substantially perpendicular to the direction in which the laser beam penetrates or transmits into the battery module 1 by the insertion portion 213 and the coupling groove portion 310, it can be effectively prevented.

That is, a phenomenon in which the laser beam is transmitted into the battery cell stack 100 is damaged can be effectively prevented.

In addition, as shown, the insertion part 213 formed on the upper end 211 of the side frame 210, which becomes the free end, is inserted into the coupling groove 310 of the upper frame 300 and maintained.

Therefore, since the upper end 211 of the side frame 210, which can be relatively easily deformed by external force compared to the lower end, can be constrained in both directions including the inward and outward directions, without adding a separate coupling means. The rigidity of the upper end 211 of the side frame 210 may be reinforced.

That is, as shown, the coupling groove 310 may function as a stopper for restraining the inward and outward movement of the insertion portion 213 . Accordingly, the joint surface or contact surface between the upper frame 300 and the side frame 210 is effectively prevented from being spread or damaged unless external pressure Fout and internal pressure Fin are applied at a predetermined level or higher.

As described above, the present invention has been described with reference to the drawings illustrated, but the present invention is not limited by the embodiments and drawings disclosed herein, and various modifications are made by those skilled in the art within the scope of the technical idea of the present invention. It is obvious that variations can be made. In addition, although the operation and effect according to the configuration of the present invention have not been explicitly described and described while describing the embodiments of the present invention above, it is natural that the effects predictable by the corresponding configuration should also be recognized.

1: battery module 100: battery cell
200: lower frame 210: side frame
211: upper part 213: insertion part
W2: upper part thickness 212: stepped surface
W3: step surface thickness 220: bottom frame
300: upper frame 301: lower surface
310: coupling groove W1: width of coupling groove
L: Laser welding H1: Depth of mating groove
H2: Insertion height Fin: Internal pressure
Fout: external pressure

Claims (10)

A battery cell laminate formed by stacking a plurality of battery cells;
A bottom frame covering a lower portion of the battery cell stack;
a pair of side frames integrally formed with the bottom frame and covering both side surfaces of the battery cell stack; and
An upper frame covering an upper surface of the battery cell stack;
including,
The bottom frame is a battery module having a coupling groove into which the upper ends of the pair of side frames are at least partially inserted.
In paragraph 1,
The coupling groove is a battery module formed on the bottom surface of the bottom frame facing the battery cell stack.
In paragraph 2,
The coupling groove portion is a battery module that extends linearly along the longitudinal direction of the upper ends of the pair of side frames.
In paragraph 3,
A battery module having an insertion portion inserted into the coupling groove at an upper end of the pair of side frames.
In paragraph 4,
A battery module having a thickness of the insertion portion smaller than a thickness of the pair of side frames.
In paragraph 4,
A battery module having a stepped surface formed at an upper end of the pair of side frames at a lower position than the insertion part in a vertical direction.
In paragraph 6,
A battery module in which the height of the insertion part from the stepped surface in the vertical direction is smaller than or equal to the depth of the coupling groove from the stepped surface.
In paragraph 6,
The width of the insertion portion is smaller than or equal to the width of the coupling groove portion of the battery module.
In paragraph 6,
The stepped surface is in surface contact with the bottom surface of the upper frame.
In paragraph 9,
The battery module wherein the stepped surface and the lower surface of the upper frame are coupled through laser welding.

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