Battery pack

A battery pack including a plurality of bare cells electrically connected to one another; and a housing including a bottom portion accommodating the bare cells therein, a middle portion mounted on the bottom portion, and a top portion on the middle portion, the top portion including a first fastening portion, and the middle portion including a second fastening portion facing the first fastening portion, and at least a portion of the first fastening portion or the second fastening portion is spaced apart from the other of the first fastening portion or the second fastening portion.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to and the benefit of Korean Patent Application No. 10-2013-0103761, filed on Aug. 30, 2013 in the Korean Intellectual Property Office, the entire content of which is incorporated herein by reference.

BACKGROUND

Aspects of embodiments of the present invention relate to a battery pack.

2. Description of the Related Art

A high-power battery module using a non-aqueous electrolyte with high energy density has recently been developed. The high-power battery module is configured as a large-capacity battery module manufactured by connecting a plurality of battery cells in series, and is used, for example, in driving motors of devices requiring high power, e.g., electric vehicles, hybrid vehicles, and the like.

A battery pack may be formed by accommodating one or more battery modules in a housing. The battery pack may be used as a power source for an external device. In this case, bare cells constituting the battery module may be secondary batteries including a lithium compound, which can be reversibly charged/discharged. In order to stably use a lithium compound having excellent reactivity with moisture, various studies have been conducted to implement the light weight of a housing of a battery pack and to improve the safety of the battery pack.

SUMMARY

According to an aspect of embodiments of the present invention, a battery pack includes a novel housing.

According to another aspect of embodiments of the present invention, a battery pack has an improved waterproof structure.

According to one or more embodiments of the present invention, a battery pack includes: a plurality of bare cells electrically connected to one another; and a housing including a bottom portion accommodating the bare cells therein, a middle portion mounted on the bottom portion, and a top portion on the middle portion, the top portion including a first fastening portion, and the middle portion including a second fastening portion facing the first fastening portion, and at least a portion of the first fastening portion or the second fastening portion is spaced apart from the other of the first fastening portion or the second fastening portion.

The second fastening portion may include a base portion parallel to the first fastening portion, and a partition wall protruded toward the first fastening portion from the base portion.

The partition wall may include a first partition wall adjacent to an outer perimeter of the base portion; a second partition wall spaced apart from the first partition wall toward an inner perimeter of the base portion; and a third partition wall spaced apart from the second partition wall and adjacent to the inner perimeter of the base portion.

The first, second, and third partition walls may divide a space between the first and second fastening portions into a first space portion and a second space portion, and the first space portion may be between the first and second partition walls, and the second space portion may be between the second and third partition walls.

The battery pack may further include a buffer member between the first and second fastening portions, and the buffer member may be in the second space portion.

A thickness of the buffer member may be greater than a protruded thickness of the second partition wall from the base portion.

The first fastening portion may contact an end portion of the partition wall, and the buffer member may be compressed in the second space portion.

The buffer member may be forcibly inserted into the second space portion.

The bottom portion may include a box-shaped accommodating portion including an open side to accommodate the bare cells; and a third fastening portion at a perimeter of the accommodating portion, and the third fastening portion may face the second fastening portion.

A first height from the base portion of a first surface of the second partition wall that faces the first space portion may be greater than a second height from the base portion of a second surface of the second partition wall that faces the second space portion.

A depth of the first space portion may be greater than that of the second space portion.

A portion of the middle portion may be accommodated inside the accommodating portion of the bottom portion, and the second fastening portion of the middle portion may be mounted on the third fastening portion.

The top portion may be spaced apart from the portion of the middle portion, and the first fastening portion may be parallel to the second fastening portion.

The first, second, and third fastening portions may be parallel to each other and facing one another, and one or more fastening holes may be formed in each of the first and second fastening portions.

The one or more fastening holes formed in the first fastening portion and the one or more fastening holes formed in the second fastening portion may be formed at positions corresponding to each other.

The third fastening portion may include one or more fastening projections corresponding to the one or more fastening holes of the first and second fastening portions.

The one or more fastening projections may be fastened to a fastening member at an outside of the first fastening portion.

As described above, according to an aspect of embodiments of the present invention, a battery pack includes a novel housing.

Further, according to another aspect of embodiments of the present invention, a battery pack has an improved waterproof structure.

DETAILED DESCRIPTION

In the following detailed description, certain exemplary embodiments of the present invention are shown and described, simply by way of illustration. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention. Accordingly, the drawings and description are to be regarded as illustrative in nature and not restrictive. It will be understood that when an element is referred to as being “between” two elements, it can be the only element between the two elements, or one or more intervening elements may also be present. In addition, when an element is referred to as being “on” another element, it can be directly on the another element or indirectly on the another element with one or more intervening elements interposed therebetween. Similarly, when an element is referred to as being “connected to” another element, it can be directly connected to the another element or indirectly connected to the another element with one or more intervening elements interposed therebetween.

FIG. 1is a perspective view of a battery pack according to an embodiment of the present invention.FIG. 2is an exploded perspective view of the battery pack ofFIG. 1.

A battery pack100according to an embodiment of the present invention includes a plurality of bare cells10electrically connected to one another; and a housing including a bottom portion130accommodating the bare cells10therein, a middle portion120mounted on a top of the bottom portion130, and a top portion110provided at a top of the middle portion120. The top portion110is provided with a first fastening portion112, and the middle portion120is provided with a second fastening portion122facing the first fastening portion112. At least a portion between the first and second fastening portions112and122may be spaced. In one embodiment, a buffer member150is interposed between the first and second fastening portions112and122.

A plurality of battery modules20may be provided in the housing. The battery module20may be provided by aligning a plurality of the bare cells10and bundling the plurality of battery cells10, such as using a pair of end plates18and a connecting member19for connecting the end plates18. In one embodiment, barriers50may be respectively provided between the aligned bare cells10. The barrier50allows adjacent bare cells10to be spaced apart from each other, thereby providing a flow path of a fluid, such as a heat exchange medium. The heat exchange medium may be heat-exchanged with the bare cells10to control the temperature of the bare cells10.

The bare cell10may be a secondary battery which can be reversibly charged/discharged. The bare cell10may include a battery case, and an electrode assembly and an electrolyte, which are accommodated in the battery case. The battery case, in one embodiment, is hermetically sealed with a cap assembly14having a positive electrode terminal11, a negative electrode terminal12, and a vent13. The electrode assembly and the electrolyte generate electrochemical energy by a reaction therebetween, and the generated energy is transferred to the outside of the bare cell10through the positive and negative electrode terminals11and12. In one embodiment, the positive and negative electrode terminals11and12of adjacent bare cells10are electrically connected through a bus bar15, and the bus bar15may be fixed to the positive and negative electrode terminals11and12of the adjacent bare cells10using a member such as a nut16. The vent13is a safety member of the bare cell10, which acts as a passage through which gas generated inside the bare cell10may be exhausted to the outside of the bare cell10.

The bare cells10electrically and physically connected in the form of the battery module20may be accommodated in the housing. The housing, in one embodiment, includes the top portion110, the middle portion120, and the bottom portion130. The battery modules20may be accommodated in the bottom portion130.

The bottom portion130, in one embodiment, includes a box-shaped accommodating portion131of which one side is open to accommodate the bare cells10(or the battery modules20), and a third fastening portion132is provided at a perimeter of the accommodating portion131. The third fastening portion132may face the second fastening portion122. In one embodiment, the third fastening portion132is provided to surround the open side of the accommodating portion131. The third fastening portion132may be extended to the outside of the accommodating portion131. The bare cells10(or the battery modules20) may be accommodated in an inside131aof the accommodating portion131. Although not shown in the drawings, an inlet, an outlet, etc., through which a heat exchange medium for performing a heat exchange with the bare cell10is flowed in the battery pack or flowed out from the battery pack, may be provided at a part of the bottom portion130, such as at a side surface of the bottom portion130.

In one embodiment, a middle body portion121of the middle portion120is inserted into the inside131aof the accommodating portion131of the bottom portion130. The second fastening portion122of the middle portion120may be mounted on the third fastening portion132. In one embodiment, when the bare cells10are accommodated in the accommodating portion131of the bottom portion130, an extra space exists above the bare cells10. The middle body portion121may be inserted into the extra space above the bare cells10. The middle body portion121may be spaced apart from the bare cells10. The second fastening portion122is provided at a perimeter of the middle body portion121, to be mounted on the third fastening portion132.

The top portion110is provided to be spaced apart at a portion from the middle portion120. In one embodiment, the first fastening portion112of the top portion110may be provided in parallel with the second fastening portion122. In one embodiment, the top portion110may include a top body portion111configured to face the middle body portion121, and the first fastening portion112provided at a perimeter of the top body portion111.

The top body portion111of the top portion110may be protruded in a direction opposite from that of the middle body portion121of the middle portion120such that a space is provided therebetween. The space between the top body portion111and the middle body portion121may be made of together of an inside of the top body portion111and an inside121aof the middle body portion121. The first fastening portion112connected to the top body portion111and the second fastening portion122connected to the middle body portion121are overlapped with each other, to support the top body portion111and the middle body portion121such that the top body portion111and the middle body portion121are spaced apart from each other. In one embodiment, an electronic component such as a battery management system (BMS), which is electrically connected to the battery module20, may be mounted in the inside121aof the middle body portion121.

The top portion110, the middle portion120, and the bottom portion130are stacked (e.g., sequentially stacked). The first to third fastening portions112,122, and132respectively provided to the top portion110, the middle portion120, and the bottom portion130may be provided in parallel to face each other. In one embodiment, one or more fastening holes113may be formed in the first fastening portion112, and one or more fastening holes123may be formed in the second fastening portion122. The fastening holes113formed in the first fastening portion112, and the fastening holes123formed in the second fastening portion122may be provided at positions corresponding to each other. The third fastening portion132may include one or more fastening projections133(e.g., threaded fastening projections) protruded to correspond to the fastening holes113and123.

In one embodiment, the fastening projections133may be inserted into the fastening holes113and123of the first and second fastening portions112and122and then fixed by being fastened with a fastening member30(e.g., a threaded nut) on an outer surface of the first fastening portion112. The fastening projections133inserted into the fastening holes113and123may guide the positions of the middle portion120and the top portion110at the top of the bottom portion130. Thus, the bottom portion130, the middle portion120, and the top portion110can be easily aligned at a correct position. The fastening holes113and123, in one embodiment, may be provided not to overlap with the buffer member150.

A portion at which the first and second fastening portions112and122are overlapped with each other and a portion at which the first and second fastening portions112and122are spaced apart from each other may be provided between the first and second fastening portions112and122. The buffer member150may be provided at the spaced apart portion. In one embodiment, one or more partition walls may be provided to at least one of the first and second fastening portions112and122, to allow portions of the first and second fastening portions112and122to be spaced apart from each other. It is described further below that, in one embodiment, one or more partition walls are provided to the second fastening portion122. However, the present invention is not limited thereto, and, in another embodiment, partition walls may be provided to the first fastening portion112.

FIG. 3is a perspective view of the middle portion120and the buffer member150, according to an embodiment of the present invention.FIG. 4Ais an enlarged view showing the region “A” ofFIG. 3.FIG. 4Bis a sectional view taken along the line I-I ofFIG. 4A.FIG. 5is a sectional view taken along the line II-II ofFIG. 1.

Referring toFIG. 3, the second fastening portion122, in one embodiment, may include a base portion122aprovided in parallel to the first fastening portion112, and a partition wall124protruded toward the first fastening portion112from the base portion122ato allow portions of the first and second fastening portions112and122to be spaced apart from each other. The partition wall124, in one embodiment, may include a first partition wall124aprovided adjacent to an outer perimeter of the base portion122a, a second partition wall124bspaced apart from the first partition wall124ato be provided inside the base portion122a, and a third partition wall124cspaced apart from the second partition wall124bto be provided adjacent to an inner perimeter of the base portion122a. The first to third partition walls124a,124b, and124cmay be spaced apart from each other at an interval (e.g., a predetermined interval) and extended in parallel to each other on the base portion122a.

Referring toFIGS. 4A and 4B, in one embodiment, the first to third partition walls124a,124b, and124cdivide the base portion122ainto a first space portion125aand a second space portion125b. The first space portion125ais provided between the first and second partition walls124aand124b, and the second space portion125bis provided between the second and third partition walls124band124c, such that the first and second space portions125aand125bare at a perimeter of the bare cells10. The buffer member150may be interposed between the first and second fastening portions112and122. In one embodiment, the buffer member150is inserted into the second space portion125b, and the first space portion125ais provided as an empty space, and the second space portion125bis filled by the buffer member150.

In one embodiment, a thickness T1of the buffer member150is greater than a protruded thickness T2of the second partition wall124b, and the buffer member150may be forcibly inserted into the second space portion125b. In one embodiment, for example, the buffer member150may be made of a material having elasticity, such as sponge. The buffer member150inserted into the second space portion125bmay protrude above the second partition wall124b.

Referring toFIG. 5, the second fastening portion122is fastened to the first fastening portion112. In one embodiment, the buffer member150protruding above the second partition wall124bmay be compressed by the first fastening portion112. That is, the first to third fastening portions112,122, and132are fixed by the protruding projection133, the fastening holes113and123, and the fastening member30. In one embodiment, the first to third fastening portions112,122, and132may be fastened while compressing the buffer member150. The first fastening portion112may contact an end portion of the partition wall124by compressing the buffer member150. In one embodiment, the fastening holes123are provided in the first space portion125a, such that the fastening projections133do not pass through the buffer member150.

The bare cell10, in one embodiment, may include a compound such as a lithium compound having excellent reactivity with water. In addition, the bare cell10, the electronic component, and the like are provided inside the housing, and, therefore, it is necessary that the inflow of moisture be prevented or substantially prevented. While in a housing of a battery pack, a parting portion at which a top portion, a middle portion, and a bottom portion are fastened to one another may be susceptible to the inflow of moisture or the like, in the battery pack according to embodiments of the present invention, the first and second space portions125aand125band the buffer member150absorbing the moisture are further provided at the parting portion where the top portion110, the middle portion120, and the bottom portion130are fastened to one another. Thus, moisture that may enter in the housing is blocked or mostly blocked, such that the lifespan of the battery pack is improved.

In one embodiment, the first and second space portions125aand125bare provided between the first and second fastening portions112and122. In this case, a space is provided in the first space portion125aprovided at an outside of the battery pack100, and the buffer member150may be provided in the second space portion125b. Thus, the moisture entering between the first and second fastening portions112and122may be primarily received in the first space portion125a, and, accordingly, it is possible to block the moisture flowed into an inside of the housing. In addition, a portion of the moisture flowed out from the first space portion125a, that is, entering into the second space portion125b, may be absorbed in the buffer member150. The flow of the moisture in the battery pack100can be effectively blocked by the first space portion125a, and it is possible to decrease the amount of the moisture to be absorbed by the buffer member150. The buffer member150is forcibly inserted into the second space portion125, such that the fastening between the first to third fastening portions112,122, and132can be firmly performed. Further, due to the buffer member150, it is possible to further ensure that a flow of the moisture into the battery pack100is blocked.

Another embodiment of the present invention is described below with reference toFIGS. 6A and 6B. Components and features of this embodiment, except as described below, may be the same or similar to those of the battery pack100described above with reference toFIGS. 1 to 5, and, therefore, further detailed description thereof will not be repeated.

FIG. 6Ais a schematic partial perspective view of a middle portion and a buffer member of a battery pack, according to another embodiment of the present invention.FIG. 6Bis a sectional view taken along the line III-III ofFIG. 6A.

Referring toFIGS. 6A and 6B, the battery pack according to another embodiment of the present invention may include a housing, and one or more battery modules provided inside the housing. The housing may include a bottom portion configured to accommodate the battery modules, and a middle portion220and a top portion, which are provided at a top of the bottom portion. A buffer member250may be provided between the middle portion220and the top portion, and the middle portion220may be provided with a second fastening portion222through which the middle portion220is fastened to the top portion and the bottom portion.

The second fastening portion222, in one embodiment, includes a base portion222a, and a partition wall224vertically protruded on the base portion222a. The partition wall224, in one embodiment, includes first, second, and third partition walls224a,224b, and224cprovided adjacent one another from an outside toward an inside of the partition wall224. A first space portion225amay be provided between the first and second partition walls224aand224b, and a second space portion225bmay be provided between the second and third partition walls224band224c.

The buffer member250is inserted into the second space portion225b, and the first space portion225amay have a space in which moisture entering into the first space portion225ais confined. The second partition wall224bprovided between the first and second space portions225aand225bmay be provided such that an outer surface and an inner surface of the second partition wall224bhave different heights from each other. In one embodiment, a first height S1of the second partition wall224bprotruded from a surface of the base portion222a, which faces the first space portion225a, is greater than a second height S2of the second partition wall224bprotruded from a surface of the base portion222a, which faces the second space portion225b. Thus, in one embodiment, a depth of the first space portion225ais formed deeper than that of the second space portion225b. The buffer member250may be provided while being compressed in the second space portion225b. The space of the first space portion225ais formed deeper than that of the second space portion225b, such that a greater amount of moisture can be confined in the first space portion225a. Thus, it is possible to further decrease the amount of moisture to be absorbed by the buffer member250. Therefore, moisture is effectively blocked from entering in the battery pack.

While the present invention has been described in connection with certain exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments. Although specific terms are employed, they are used and are to be interpreted in a generic and descriptive sense only and not for purpose of limitation. In some instances, as would be apparent to one of ordinary skill in the art, features, characteristics, and/or elements described in connection with a particular embodiment may be used singly or in combination with features, characteristics, and/or elements described in connection with other embodiments unless otherwise indicated. Accordingly, it will be understood by those of skill in the art that various changes in form and details may be made without departing from the spirit and scope of the present invention as set forth in the following claims and equivalents thereof.