Battery module

A battery module includes a plurality of battery cells stacked together; first and second end plates located at a first end and a second end, respectively, of the stacked battery cells; and side plates and a bottom plate coupled to the first and second end plates, wherein at least one of the first end plate and the second end plate has a bent support portion that overlaps with at least a portion of the bottom plate.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to and the benefit of Korean Patent Application No. 10-2011-0013340, filed on Feb. 15, 2011, in the Korean Intellectual Property Office, the entire content of which is incorporated herein by reference.

BACKGROUND

Embodiments of the present invention relate to a battery module.

2. Description of 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 so as to be used in driving motors of devices requiring high power, e.g., electric vehicles and the like.

A battery cell typically includes an electrolyte and an electrode assembly composed of a positive plate and a negative electrode plate, and generates energy through an electrochemical reaction of these electrode plates and the electrolyte. Gas may be generated as a side reaction of the electrochemical reaction in the interior of the battery cell, and the generated gas may change the external shape of the battery cell. Further, the change in the external shape of the battery cell has influence on the shape of a battery module formed by aligning a plurality of battery cells, and therefore, the battery cells may not be firmly fixed in the battery module. Accordingly, various types of battery modules have been developed to minimize a change in the external shape of battery cells and to enhance productivity of the battery modules.

SUMMARY

Embodiments provide a battery module capable of improving reliability by strengthening a housing of the battery module. Embodiments also provide a battery module capable of minimizing the size and weight of the battery module by distributing the load of a plurality of battery cells.

A battery module including a plurality of battery cells stacked together; first and second end plates located at a first end and a second end, respectively, of the stacked battery cells; and side plates and a bottom plate coupled to the first and second end plates, wherein at least one of the first end plate and the second end plate has a bent support portion that overlaps with at least a portion of the bottom plate.

In one embodiment, the bent support portion extends from a bottom portion of the first or second end plate generally towards the battery cells and the bottom plate connects the first and second end plates to each other and is located between the first and second plates. Additionally, the first or second end plate may have a first fastening hole on a portion that contacts an end of the bottom plate, and wherein the bottom plate has a second fastening hole that is generally aligned with the first fastening hole. In one embodiment, the first and second fastening holes accommodate a fixing member.

In one embodiment, the first or second end plate includes a base plate contacting a peripheral one of the battery cells and at least one flange portion bent away from the battery cells from at least one of a side portion or a bottom portion of the base plate. Further, in one embodiment, the bottom plate contacts the base plates of the first and second end plates and is mounted on the bent support portions of at least one of the first end plate or the second end plate. The bent support portion may further include a third fastening hole through which a fastener extends to fix the bottom plate to the bent support portion.

In one embodiment, the flange portions comprise at least two lower flange portions spaced from each other on the base plate, and wherein the bent support portion is located between the flange portions. A width of the bent support portion may be substantially identical to the base plate and at least a portion of the flange portion may be coupled to an end of the side plate.

As described above, according to embodiments of the present invention, it is possible to provide a battery module including a housing capable of firmly fixing a plurality of battery cells.

Also, it is possible to provide a battery module capable of reducing the size and weight of the battery module by effectively distributing the load of a plurality of battery cells.

DETAILED DESCRIPTION

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

The battery module100according to this embodiment includes a plurality of battery cells10stacked together and aligned in one direction, first and second end plates110and120located at either end of the stacked battery cells10, and side and bottom plates130and140that connect the first and second end plates110and120and support both side surfaces of the battery cells10. The first or second end plate110or120include bent support portions114and124that overlap at least a portion of the bottom plate140.

The battery cell10may be manufactured by accommodating an electrode assembly and an electrolyte in a battery case and then sealing the battery case with a cap plate14. The cap plate14may include positive and negative electrode terminals11and12, and a vent13located between the terminals11and12. The electrode assembly is composed of a positive electrode plate, a negative electrode plate and a separator between electrode plates. The positive electrode plate is connected to the positive electrode terminal11, and the negative electrode plate is connected to the negative electrode terminal12so that energy generated by an electrochemical reaction between the electrode assembly and the electrolyte is transferred to the exterior of the battery cell10. The vent13serves as a path along which gas generated in the interior of the battery cell10can be exhausted to the exterior of the battery cell10.

The pair of the first and second end plates110and120and the side and bottom plates130and140that connect the first and second end plates110and120accommodate the plurality of battery cells10. The battery cells10may be aligned and fixed in one direction within the provided space. In one embodiment, the battery cells10are aligned in parallel so that wide planar surfaces of neighboring battery cells10are opposite to each other. The positive and negative electrode terminals11and12may be electrically connected through bus-bars15. The bus-bar15has openings through which the positive and negative electrode terminals11and12can pass. The bus-bar15connected to the terminals respectively passing through the holes may be fixed by a member including a nut16or the like.

The first and second end plates110and120are oriented to contact one of the outermost battery cells so that they can together apply a compressive force to the battery cells10. In one embodiment, the positive and negative electrode terminals11and12of the plurality of battery cells10supported by the first and second end plates110and120, the side plates130and the bottom plate140may be alternately aligned to be connected in series.

The first and second end plates110and120, the side plates130and the bottom plate140constitute a housing for stably fixing the plurality of battery cells10. The housing may be implemented by being variously modified according to the design target of the battery module100.

In one embodiment, the first and second end plates110and120include respective base plates113and123and flange portions111,112, and121,122. The base plates113and123are oriented parallel to the battery cells10, and the flange portions111,112,121and122may be provided to be bent to extend away from the battery cells10from at least one edge of the base plates113and123.

The base plates113and123have a size similar to the wide front surface of the battery cell10so as to at least partially cover the external shape of the battery cell10. In this embodiment, the base plates113and123may have an approximately rectangular shape generally corresponding to the battery cell10. However, the present invention is not limited thereto.

The flange portions111,112, and121,122may include side flange portions111and121extending from the side portions of the base plates113and123, respectively, and bottom flange portions112and122extending from the bottom portions of the base plates113and123, respectively. The side flange portions111and121are portions respectively coupled to ends131,132of the side plate130. The coupling force between the side plate130and the side flange portions111and121can be enhanced using bolts20or the like

FIG. 3Ais a perspective view showing a state that the end plates are connected to the bottom plate.FIG. 3Bis a bottom perspective view of a bottom portion of the battery module according to the embodiment of the present invention.

Referring toFIGS. 3A and 3B, the first or second end plate110or120may include the bent support portions114and124that overlap with at least portions of the bottom plate140. The bottom plate140connects the first and second end plates110and120to each other and is provided between the first and second end plates110and120. Each end141and142of the bottom plate140contacts the base plates113and123of the first and second end plates110and120, respectively.

In the first and second end plates110and120, the flange portions111,112,121and122may include at least two lower flange portions112and122, respectively, spaced from each other at the bottom portions of the base plates113and123. The bent support portions114and124may be provided between the lower flange portions112and122. The bent support portions114and124may be provided so that each of the bent support portions extends from the bottom portion of the first or second end plate110or120toward the battery cells10.

One or more holes112aand122amay be provided to the respective lower flange portions112and122for mounting the battery module10on a flat part or to fix between neighboring battery modules.

Since the bottom plate140supports the load of the plurality battery cells10, it typically has a higher rigidity than the side plates130or the first and second end plates110and120. The fastening force between the bottom plate140and the first and second end plates110and120is sufficient to support the load of the plurality of the battery cells10.

In this embodiment, the bent support portions114and124are provided on the respective first and second end plates110and120so that the bottom plate140can distribute the load of the battery cells10concentrated on the bottom plate140to the first and second end plates110and120. Since stress applied to portions at which the first and second end plates110and120are fastened to the bottom plate140can be distributed, it is possible to improve the stability of the battery module100against an external impact such as a vibration or impact.

Generally, the bottom plate140is made of a material such as SUS with high rigidity to support the load concentrated on the bottom plate140. However, the battery module100according to this embodiment is not limited thereto. For example, in the battery module100according to this embodiment, the bottom plate140may be made of plastic or the like, which has relatively low rigidity. The bottom plate140made of a plastic resin material has a lower rigidity than the SUS or the like, but minimizes the weight and size of the battery module and has plasticity, and thus the design of the battery module can be more easily modified. Further, the plastic resin bottom plate140has excellent insulation properties, and thus the stability of the battery module can be improved.

The bottom plate140may be provided to contact the base plates113and123of the first and second end plates110and120and to be mounted on the bent support portions114and124of the first and second plates110and120. The first or second end plate110or120is provided with a first fastening hole113aor123aat a portion that contacts the one or the other end141or142of the bottom plate140. The bottom plate140may have a second fastening hole141aor142agenerally corresponding to the first fastening hole113aor123.

The first and second fastening holes113a,123a,141aand142aare provided so that corresponding first and second fastening holes are aligned with each other. The first and second fastening holes113a,123a,141aand142a30receive fixing members30to improve the fastening force between the bottom plate140and the first and second end plates110and120. For example, the fixing member30may include a bolt or stud.

Since the first and second fastening holes113a,123a,141aand142aare fastened to be generally perpendicular to the load of the battery cells10which is concentrated on the bottom plate140, the load of the battery cells10can be distributed.

Hereinafter, another embodiment of the present invention will be described with reference toFIGS. 4A to 6B. In this embodiment, details except the following description are similar to those described inFIGS. 1 to 3B, and therefore, their detailed descriptions will be omitted.

FIG. 4Ais a perspective view of a first end plate and a bottom plate according to another embodiment of the present invention.FIG. 4Bis a perspective view of a bottom portion ofFIG. 4A.

Referring toFIGS. 4A and 4B, in a battery module according to this embodiment, the bottom plate240may be provided to contact a base plate213of the first end plate210and to be mounted on a bent support portion214of the first end plate210.

The first end plate210includes at least one lower flange portion212bent away from the battery cells from a bottom portion of the base plate213. The bent support portion214may include one or more bent support portions214aand214bspaced from each other. In one embodiment, the lower flange portion212may be provided at a central portion of the base plate213between the bent support portions214aand214b.

In this embodiment, the first end plate210includes the one or more bent support portions214aand214b, and therefore, the area overlapping with the bottom plate240is maximized. Thus, the load of the battery cells which is concentrated on the bottom plate240can be more effectively distributed, thereby stably supporting the battery cells.

FIG. 5Ais a perspective view of a first end plate and a bottom plate according to still another embodiment of the present invention.FIG. 5Bis a perspective view of a bottom portion ofFIG. 5A.

Referring toFIGS. 5A and 5B, in a battery module according to this embodiment, the bottom plate340may be provided to contact a base plate313of the first end plate310and to be mounted on a bent support portion314of the first end plate310. In this instance, the width of the bent support portion314may be substantially identical to the base plate313.

In the battery module that requires no lower flange portion of the first end plate310, the width of the bent support portion314is substantially identical to the base plate313so that it is possible to effectively distribute a load applied to the bottom plate340without a change in the size of the battery module. The bent support portion314is provided only by bending a bottom portion of the base plate313without an additional cutting process so that it is possible to improve process efficiency.

FIG. 6Ais a perspective view of a first end plate and a bottom plate according to still another embodiment of the present invention.FIG. 6Bis a perspective view of a bottom portion ofFIG. 6A.

Referring toFIGS. 6A and 6B, in a battery module according to this embodiment, the bottom plate440may be provided to contact a base plate413of the first end plate410and to be mounted on a bent support portion414of the first end plate410. In this embodiment, the bent support portion414may further include third fastening holes414athrough which the bottom plate440is fixed to the bent support portion414of the first end plate410.

In the battery module according to this embodiment, the bottom plate440is fastened to the base plate413of the first end plate410, and a fastening portion of the bottom plate440is increased by the third fastening holes414aprovided to the bent support portion414so that it is possible to improve the fastening force between the first bottom plate440and the first end plate410.