Case for battery pack

A case for a battery pack includes a case member configured to accommodate a plurality of battery cells therein and a heat exchange member on any one surface of the case member, the heat exchange member being integrally formed with the case member.

CROSS-REFERENCE TO RELATED APPLICATION

Korean Patent Application No. 10-2014-0017717 filed on Feb. 17, 2014, in the Korean Intellectual Property Office, and entitled: “CASE FOR BATTERY PACK,” is incorporated by reference herein in its entirety.

BACKGROUND

Embodiments relate to a case for a battery pack.

2. Description of the Related Art

In general, battery cells are used as energy sources for mobile devices, electric vehicles, hybrid vehicles, and the like. The shape of the battery cell may be variously changed depending on the kind of external device to which the battery cell is applied.

In an electric vehicle or hybrid vehicle that consumes a large amount of power in long-time driving and high-power driving, a large-capacity battery module may be configured by electrically connecting a plurality of battery cells in order to increase power and capacity. The output voltage or output current of the battery module may be increased according to the number of battery cells built in the battery module. In addition, a battery pack may be configured by electrically connecting such battery modules.

SUMMARY

Embodiments are directed to a case for a battery pack including a case member configured to accommodate a plurality of battery cells therein, and a heat exchange member on any one surface of the case member, the heat exchange member being integrally formed with the case member.

An upper surface of the heat exchange member may include a flow path through which a cooling medium moves. The upper surface of the heat exchange member may be attached to an outer bottom surface of the case member.

An inner bottom surface of the case member may include a flow path through which a cooling medium moves. The heat exchange member may be attached to the inner bottom surface of the case member.

The heat exchange member may be in a shape of a plate.

A heat shield material may be at a lower portion of the heat exchange member.

The heat exchange member may be welded to the case member through brazing.

The case member and the heat exchange member may be manufactured through die-casting.

DETAILED DESCRIPTION

FIG. 1illustrates a perspective view showing a case for a battery pack, which includes a heat exchange member according to an embodiment.FIG. 2illustrates an exploded perspective view showing the case according to the embodiment illustrated inFIG. 1.

Referring toFIGS. 1 and 2, the case according to this embodiment may include a case member that includes upper and lower cases10and20that accommodate a plurality of battery cells10therein and a heat exchange member30provided on an outer bottom surface of the lower case20. A flow path31through which a cooling medium moves may be formed in an upper surface the heat exchange member30. The upper surface of the heat exchange member30may be attached to the outer bottom surface of the lower case20. The lower case20and the heat exchange member30may be integrally formed.

A heat exchange medium may move through the flow path31of the heat exchange member30. The heat exchange medium may be a refrigerant. The heat exchange medium may include at least one of ethylene glycol and propylene glycol.

Generally, a lower case of a battery pack and a heat exchange member are separately manufactured and then connected to each other, using a bolt, a rivet, or the like. A component such as a bolt, however, is used, and a bolt fastening process is included, thereby increasing manufacturing time and cost.

According to embodiments, a separate cover is not provided to the heat exchange member30having the flow path31formed therein. Instead, the heat exchange member30may be attached directly to the outer bottom surface of the lower case20, such that it may be possible to omit a component such as a cover, thereby reducing unit cost. The heat exchange member30may be welded to the lower case20through brazing, and each of the lower case20and the heat exchange member30may be manufactured through die-casting.

Accordingly, it may be possible to reduce an accumulated assembly tolerance generated in the manufacturing of the case, thereby improving product accuracy. Further, as the contact area between the outer bottom surface of the lower case20and the heat exchange member30increases, it may be possible to improve the reliability and the stability of the case.

Hereinafter, a battery module will be briefly described.

A battery module may include a plurality of battery cells arranged in one direction. Each battery cell may be provided with a cap plate having a terminal portion formed on an upper surface thereof. In addition, the battery cell may include with a bottom surface provided opposite to the cap plate. A heat exchange member may be provided on the bottom surface of the battery cell.

The battery cell may include a battery cell case of which one surface is opened, and an electrode assembly and an electrolyte, which are accommodated in the battery cell case. The electrode assembly and the electrolyte may generate energy through an electrochemical reaction therebetween, and the battery cell case may be sealed with the cap plate. The cap plate may be provided with the terminal portion and a vent portion. The terminal portion may include positive and negative electrode terminals having different polarities from each other. The vent portion may be a safety device of the battery cell, and may act as a passage through which gas generated inside the battery cell is exhausted to an outside of the battery cell. Positive and negative electrode terminals of battery cells adjacent to each other may be electrically connected through a bus-bar. The bus-bar may be fixed to the positive and negative electrode terminals using a member such as a nut.

The plurality of battery cells may be aligned in one direction. One or more plates may be used to maintain the alignment state of the battery cells. The plates may be used to fix the plurality of the battery cells and may be variously modified according to the design of the battery module.

Referring toFIG. 3, the heat exchange member30may be provided on the outer bottom surface of the lower case20. The flow path31through which the cooling medium moves may be formed in the upper surface40of the heat exchange member30. The upper surface40of the heat exchange member30may be attached to the outer bottom surface of the lower case20. The bottom surface of the lower case20may seal the flow path31formed in the heat exchange member30, such that it may be possible to prevent the occurrence of leakage of the heat exchange medium moving through the flow path31. Particularly, when the case configured described above is installed in a vehicle, the height of the case may be reduced by omitting a cover of the heat exchange member30. Thus, the case may be installed even in a narrow space.

The heat exchange member30according to this embodiment may be formed in the shape of a plate having a predetermined thickness. The heat exchange member30may be used to control heat generated in the battery cell. The flow path31through which the heat exchange medium flows to exchange heat with the battery module, i.e., the battery cell, may be provided in the heat exchange member30.

The heat exchange member30may be welded to the bottom surface of the lower case20through brazing. Each of the heat exchange member30and the lower case20may be manufactured through die-casting, thereby reducing an accumulated assembly tolerance that may be generated in the manufacturing of the case.

Brazing is a kind of soldering, and is a method of coupling base materials to each other without melting the base materials by penetrating a melted adhesive between the base materials. An adhesive having a melting point lower than that of the base material may be used as an adhesive for brazing. In addition, the die-casting is one of casting methods, and is a precision casting method of injecting a melted metal into a mold made of steel exactly machined to completely correspond to a required casting shape, thereby obtaining a casting equal to the mold. Accordingly, the bottom surface of the lower case20and the contact surface of the heat exchange member30may be adhered more closely to each other, and the contact surface between the bottom surface of the lower case20and the heat exchange member30may be increased, thereby improving the reliability and stability of the battery pack.

FIG. 4Aillustrates a sectional view showing a case for a battery pack according to another embodiment.FIG. 4Billustrates a sectional view showing the case including a heat exchange member according to the embodiment.

Referring toFIGS. 4A and 4B, in the case20′ according to this embodiment, a flow path31′ through which a cooling medium moves may be formed in an inner bottom surface of the case20′. In addition, the inner bottom surface of the case20′ may include a recess21′ such that the a heat exchange member30′ may be received the inner bottom surface of the case20′. The heat exchange member30′ may be formed in the shape of a plate to seal the flow path31′ formed in the inner bottom surface of the case20′. It may be possible to prevent a heat exchange medium flowing through the flow path31′ from being leaked and then condensed inside the battery pack.

The flow path31′ may be formed in the inner bottom surface of the case20′, and the case20′ and the heat exchange member30′ may be welded through brazing such that the plate-shaped heat exchange member30′ seals the flow path31′. As such, the case20′ and the heat exchange member30′ may be integrally formed.

In addition, a heat shield material such as air layer, paper, or rubber may be provided at a lower portion of the heat exchange member30′.

According to some implementations, the case20′ may be a lower case that is used with the upper case10illustrated inFIGS. 1 and 2to accommodate a battery pack.

By way of summation and review, a high-power and large-capacity battery pack generates a large amount of heat in a charging/discharging process thereof. To dissipate heat generated in the battery cells, a heat exchange member may be mounted in the high-power and high-capacity battery pack. Mounting a heat exchange member to a battery pack may increase manufacturing time and cost, and a mounted heat exchange member may take up space.

According to embodiments, one surface of a case may be substituted for a cover of the heat exchange member, so that the case and the heat exchange member may be integrally manufactured. Thus, it may be possible to omit a component, thereby reducing unit cost.

Further, the case and the heat exchange member may be welded to each other through brazing, so that a bolt fastening process may be omitted, thereby reducing manufacturing time and cost. In addition, it may be possible to reduce an accumulated assembly tolerance generated in the manufacturing of the case, thereby improving product accuracy.

Further, the contact area between the case and the heat exchange member may be increased, thereby improving the reliability and stability of the battery pack.