Battery module assembly for vehicle's battery pack

Disclosed is a battery module assembly, which includes four battery modules, each having a plurality of cylindrical secondary battery cells (hereinafter, also referred to as ‘cells’) interposed between an upper frame and a lower frame, wherein among the four battery modules, two battery modules are arranged in parallel, and two battery modules are stacked on the two battery modules arranged in parallel. Therefore, it is possible to provide a stable and economic battery module assembly including a plurality of secondary battery cells.

TECHNICAL FIELD

The present disclosure relates to a battery module assembly, and more particularly, to a mechanical connection between battery modules in a battery module assembly for a vehicle's battery pack.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is the National Phase of PCT International Application No. PCT/KR2014/003565, filed on Apr. 23, 2014, which claims priority under 35 U.S.C. 119(a) to Patent Application No. 10-2013-0047475, filed in the Republic of Korea on Apr. 29, 2013, and to Patent Application No. 10-2013-0063089, filed in the Republic of Korea on May 31, 2013, all of which are hereby expressly incorporated by reference into the present application.

DESCRIPTION OF THE RELATED ART

A secondary battery having good application to various product groups and good electric characteristics such as high energy density is widely applied to not only portable devices but also an electric vehicle (EV) or a hybrid electric vehicle (HEV) driven by an electric driving source. The secondary battery has a primary advantage of greatly reducing the use of fossil fuels and a secondary advantage of generating no byproduct in use of energy, and thus attracts attention as a new energy source for enhancing environment-friendly and energy-efficient properties.

Lithium ion batteries, lithium polymer batteries, nickel cadmium batteries, nickel hydrogen batteries, nickel zinc batteries or the like are widely used as secondary batteries at the present. Such a unit secondary battery cell has an operating voltage of about 2.5V to 4.2V. Therefore, if a higher output voltage is demanded, a plurality of secondary battery cells may be connected in series to configure a battery pack. In addition, according to a charge/discharge capacity demanded to the battery pack, a plurality of secondary battery cells may also be connected in parallel to configure a battery pack. Therefore, the number of secondary battery cells included in the battery pack may be various set depending on a demanded output voltage or charge/discharge capacity.

Meanwhile, if a plurality of secondary battery cells is connected in series or in parallel to configure a battery pack, the secondary battery cells included in the battery pack should be firmly connected electrically and mechanically. Therefore, a stable and economic design is required for a battery module assembly and a battery pack in order to ensure firm connection of secondary battery cells.

SUMMARY OF THE DISCLOSURE

The present disclosure is designed to solve the problems of the related art, and therefore the present disclosure is directed to providing a battery module assembly for a vehicle's battery pack.

In one aspect of the present disclosure, there is provided a battery module assembly, which includes four battery modules, each having a plurality of cylindrical secondary battery cells (hereinafter, also referred to as ‘cells’) interposed between an upper frame and a lower frame, wherein among the four battery modules, two battery modules are arranged in parallel, and two battery modules are stacked on the two battery modules arranged in parallel.

According to an embodiment of the present disclosure, a protrusion may be formed on a top of an upper frame of the battery module, an indent portion having a shape and location corresponding to the protrusion may be formed in a bottom portion of the lower frame, and the protrusion of any one of the stacked battery modules may be coupled to the indent portion of the other of the stacked battery modules.

According to an embodiment of the present disclosure, a connection unit may be formed at one side of the upper frame or the lower frame for a connection with another battery module, and among the four battery modules, the battery modules arranged in parallel may be connected by means of the connection unit. At this time, the connection unit may have a ‘’ or ‘’ shape.

According to an embodiment of the present disclosure, the two battery modules arranged in parallel and located at a lower portion may be connected by means of a plate provided below the battery modules. In this case, the plate provided below the battery modules may have an area greater than the sum of areas of the two battery modules arranged in parallel and located at a lower portion, and a region of the plate provided below the battery modules, which is beyond the two battery modules arranged in parallel and located at a lower portion, may be folded vertically and connected to sides of the two battery modules arranged in parallel and located at a lower portion by means of a screw.

According to an embodiment of the present disclosure, a plate whose partial region is vertically folded may be connected to tops of the two battery modules arranged in parallel and located at a lower portion, and the vertically folded region of the plate may be respectively connected to two battery modules stacked on the two battery modules arranged in parallel. At this time, threads may be formed at sides of the upper frame and the lower frame, and the vertically folded region of the plate may be connected to the upper frame or the lower frame using a screw by means of the threads.

In an aspect of the present disclosure, it is possible to provide a stable and economic battery module assembly including a plurality of secondary battery cells.

DESCRIPTION OF THE PREFERRED EMBODIMENT

FIG. 1is a perspective view showing a battery pack1including a battery module assembly50according to an embodiment of the present disclosure.

The battery pack1depicted inFIG. 1is a vehicle's battery pack1which may be mounted to a vehicle, a hybrid electric vehicle (HEV), an electric vehicle (EV) or the like.

Preferably, the battery pack1may have a size according to the standards for vehicle's batteries. Therefore, the battery pack1may have a hexagonal shape as a whole.

Also preferably, the battery module assembly50may also have a size according to the standards for vehicle's batteries. However, the battery pack1and the battery module assembly50are not limited to the above sizes, and their lengths, widths and heights may be set in various ways.

FIG. 2is an exploded perspective view showing a battery pack1including a battery module assembly50according to an embodiment of the present disclosure.

The battery module assembly50according to an embodiment of the present disclosure is connected to an inner case30and included between an upper pack case10and a lower pack case70to configure the battery pack1.

FIG. 3is a perspective view showing battery modules60of the battery module assembly50according to an embodiment of the present disclosure.

Referring toFIG. 3, the battery module60is configured so that a plurality of cylindrical secondary battery cells62(hereinafter, also referred to as ‘cells’) is interposed between an upper frame61and a lower frame63. For convenience, it will be assumed that an electrode of a cell62exposed toward the upper frame61is a high potential electrode (+), and an electrode of a cell62exposed toward the lower frame63is a low potential electrode (−). In addition, for better identification of the upper frame61and the lower frame63with naked eyes, the upper frame61is depicted in a dark color and the lower frame63is depicted in a light color.

The battery pack1according to an embodiment of the present disclosure may have an operating voltage of 12V when being used for a vehicle. In addition, a secondary battery cell62according to an embodiment of the present disclosure may have an operating voltage of 3V. Therefore, four battery modules60may be connected in series to configure a battery module assembly50.

Hereinafter, the battery module assembly50composed of battery modules60shown inFIG. 3will be described. For reference, the terms “upper”, “lower”, “top” and “bottom” used in the specification indicates locations based on the drawings.

The battery module assembly50according to an embodiment of the present disclosure is composed of four battery modules60. Hereinafter, the four battery modules60will be classified with numbers.

FIG. 4is a perspective view showing a 1stbattery module60-1among four battery modules included in the battery module assembly50according to an embodiment of the present disclosure.

Referring toFIG. 4, it may be found that a plate51is added to an upper frame61-1of the battery module60depicted inFIG. 3. The plate51is made of metal and electrically connected to a high potential terminal of the battery module60-1. Therefore, high potential terminals of the cells62-1included in the battery module60-1may be electrically connected in parallel by the plate51.

According to an embodiment of the present disclosure, the plate51may be made of any one selected from the group consisting of nickel, copper, brass and nickel-plated copper. These materials are just examples, and the plate51may be made of any kind of metal which may be easily replaced by those having ordinary skill in the art.

According to an embodiment of the present disclosure, the plate51has a thickness of 0.1 mm to 0.4 mm. The thickness may be set in various ways in consideration of rigidity, electric conductivity or the like according to properties of the metal.

According to an embodiment of the present disclosure, the plate51and the cells62-1are connected by means of resistance welding, ultrasonic welding, laser welding or conductive adhesive.

The entire area of the plate51is greater than an area of the upper frame61-1of the 1stbattery module60-1. In addition, a part of the plate51, namely a region51-abeyond the area of the upper frame61-1of the 1stbattery module60-1, is folded vertically. When configuring the battery module assembly50later, the folded region51-ais used for mechanical and electric connection with a battery module60-3(seeFIG. 7) stacked thereon.

FIG. 5is a perspective view showing a 2ndbattery module60-2among four battery modules included in the battery module assembly50according to an embodiment of the present disclosure.

Referring toFIG. 5, it may be found that the 2ndbattery module60-2has a turn-over shape of the battery module60depicted inFIG. 3. In addition, it may also be found that a plate52is added to a lower frame63-2of the 2ndbattery module60-2. The plate52is made of metal and electrically connected to a low potential terminal of the battery module60-2. Therefore, low potential terminals of the cells62-2included in the 2ndbattery module60-2may be electrically connected in parallel by means of the plate52.

Material, thickness and welding method of the plate52are substantially identical to those of the plate51ofFIG. 4.

The entire area of the plate52is greater than an area of the lower frame63-2of the 2ndbattery module60-2. In addition, a part of the plate52, namely a region52-abeyond the area of the lower frame63-2of the 2ndbattery module60-2, is folded vertically. When configuring the battery module assembly50later, the folded region52-ais used for mechanical and electric connection with a battery module60-4(seeFIG. 7) stacked thereon.

FIG. 6is an exploded perspective view showing that the 1stand 2ndbattery modules60-1,60-2among four battery modules included in the battery module assembly50according to an embodiment of the present disclosure are connected.

Referring toFIG. 6, it may be found that a plate53is disposed at bottoms of the 1stand 2ndbattery modules60-1,60-2.

The plate53is made of metal and electrically connected to the low potential terminal of the 1stbattery module60-1. Therefore, low potential terminals of the cells62-1included in the 1stbattery module60-1may be electrically connected in parallel by means of the plate53. Meanwhile, the plate53is made of metal and electrically connected to a high potential terminal of the 2ndbattery module60-2. Therefore, high potential terminals of the cells62-2included in the 2ndbattery module60-2may be electrically connected in parallel by means of the plate53. Simultaneously, the plate53has an area including both the 1stbattery module60-1and the 2ndbattery module60-2. Therefore, the low potential terminal of the 1stbattery module60-1and the high potential terminal of the 2ndbattery module60-2may be electrically connected in series.

Material, thickness and welding method of the plate53are substantially identical to those of the plate51ofFIG. 4.

According to an embodiment of the present disclosure, the entire area of the plate53is greater than the sum of areas of the 1stbattery module60-1and the 2ndbattery module60-2. In addition, a part of the plate53, namely a region53-abeyond the sum area of the 1stbattery module60-1and the 2ndbattery module60-2, is folded vertically. Moreover, threads68are formed at a side of the 1stbattery module60-1and a side of the 2ndbattery module60-2. Therefore, a screw hole may be formed in the vertically folded region53-a, and the plate53may be mechanically connected to the 1stbattery module60-1and the 2ndbattery module60-2by means of the threads68and screws.

According to an embodiment of the present disclosure, in the battery module60, connection units67,67-1are formed at one side of the upper frame61or the lower frame63for a connection to another battery module.

Referring toFIG. 3again, the connection units67,67-1formed at the sides of the upper frame61and the lower frame63of the battery module60are depicted. As described above, in the battery pack1according to an embodiment of the present disclosure, four battery modules60configure the battery module assembly50(seeFIG. 2). At this time, the battery module60may be mechanically coupled to another battery module60adjacent to a side thereof by means of the connection units67,67-1.

According to an embodiment of the present disclosure, the connection units67,67-1have ‘’ or ‘’ shape. The connection unit67having a ‘’ shape and the connection unit67-1having a ‘’ shape may be connected to each other to prevent the battery module60from being deviated in a horizontal direction. For this, when configuring the battery module assembly50battery modules60adjacent to each other may be arranged so that the connection unit67having a ‘’ shape and the connection unit67-1having a ‘’ shape are connected to each other.

If the connection units67,67-1are formed at the sides of the 1stbattery module60-1and the 2ndbattery module60-2, the 1stbattery module60-1and the 2ndbattery module60-2may be mechanically connected by means of the connection units67,67-1. The connection units67,67-1enhance a mechanical coupling power among the battery modules60of the battery module assembly50.

FIG. 7is an exploded perspective view showing that the 3rdand 4thbattery modules60-3,60-4among four battery modules included in the battery module assembly50according to an embodiment of the present disclosure are stacked.

Referring toFIG. 7, a plate54is coupled to a high potential terminal of the 3rdbattery module60-3. In addition, a plate55is coupled to a low potential terminal of the 3rdbattery module60-3. The cells62-3included in the 3rdbattery module60-3may be electrically connected in parallel by means of the plates54,55.

A plate56is coupled to a high potential terminal of the 4thbattery module60-4. In addition, a plate57is coupled to a low potential terminal of the 4thbattery module60-3. The cells62-4included in the 4thbattery module60-4may be electrically connected in parallel by means of the plates56,57.

Referring toFIG. 7, it may be found that the 3rdbattery module60-3and the 4thbattery module60-4are respectively stacked on the 1stbattery module60-1and the 2ndbattery module60-2arranged in parallel.

The 3rdbattery module60-3is electrically connected to the 1stbattery module60-1in series. Therefore, the low potential terminal of the 3rdbattery module60-3is stacked to be adjacent to the high potential terminal of the 1stbattery module60-1.

In addition, the 4thbattery module60-4is electrically connected to the 2ndbattery module60-2in series. Therefore, the high potential terminal of the 4thbattery module60-4is stacked to be adjacent to the low potential terminal of the 2ndbattery module60-2.

According to an embodiment of the present disclosure, a protrusion66is formed on a top of the upper frame61of the battery module60, and an indent portion66-1having a shape and location corresponding to the protrusion66is formed in a bottom of the lower frame63.

Referring toFIGS. 3 to 5again, it may be found that the protrusion66is formed at the top of the upper frame61according to an embodiment of the present disclosure, and the indent portion66-1having a shape and location corresponding to the protrusion66is formed at the bottom of the lower frame63.

As described above, in the battery pack1according to an embodiment of the present disclosure, four battery modules60configure the battery module assembly50(seeFIG. 2). At this time, when the battery modules60-1to60-4are stacked vertically, the protrusion66and the indent portion66-1may fix locations of the battery module located at the above and the battery module located at the below. In addition, when the battery modules60-1to60-4are stacked by means of the protrusion66and the indent portion66-1, the battery modules60may be easily stacked, and it is also possible to prevent the upper battery module60and the lower battery module60from deviating from proper locations.

When the protrusion66and the indent portion66-1are formed at the 1stand 3rdbattery modules60-1,60-3, the 1stbattery module60-1and the 3rdbattery module60-3may be mechanically connected by means of the protrusion66and the indent portion66-1. In addition, when the protrusion66and the indent portion66-1are formed at the 2ndand 4thbattery modules60-2,60-4, the 2ndbattery module60-2and the 4thbattery module60-4may be mechanically connected by means of the protrusion66and the indent portion66-1.

Meanwhile, the 1stbattery module60-1and the 3rdbattery module60-3may be mechanically and electrically connected by means of the vertically folded region51-aof the plate51. In addition, the 2ndbattery module60-2and the 4thbattery module60-4may be mechanically and electrically connected by means of the vertically folded region52-aof the plate52. At this time, the mechanical connection may be made using the thread68formed at the lower frame of the 3rdbattery module60-3, the vertically folded region51-aof the plate51and screws. Similarly, the mechanical connection may also be made using the thread68formed at the upper frame of the 4thbattery module60-4, the vertically folded region51-aof the plate51and screws.

FIG. 8is a perspective view showing a battery module assembly50according to an embodiment of the present disclosure.

Referring toFIG. 8, it may be found that the battery modules60-1to60-4depicted inFIGS. 4 to 7are mechanically and electrically connected.

According to an embodiment of the present disclosure, the battery modules60stacked vertically, namely the 1stbattery module60-1and the 3rdbattery module60-3, and also the 2ndbattery module60-2and the 4thbattery module60-4are electrically connected in series by means of a bus bar58. The bus bar58may also be connected between the 1stbattery module60-1and the 3rdbattery module60-3and between the 2ndbattery module60-2and the 4thbattery module60-4by means of screws.

According to the present disclosure, it is possible to provide a stable and economic battery module assembly including a plurality of secondary battery cells.