Battery module

A battery module including a plurality of battery cells arranged in one direction; heat insulating members interposed between the plurality of battery cells so as to control heat generated in the battery cells; and a housing fixing the battery cells and the heat insulating members.

The present application claims priority under 35 U.S.C. §119 to Korean Patent Application No. 10-2013-0001167, filed on Jan. 4, 2013, in the Korean Intellectual Property Office, and entitled: “Battery Module,” which is incorporated by reference herein in its entirety.

BACKGROUND

Embodiments relate to a battery module.

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 so as to be used for driving devices, e.g., motors of electric vehicles and the like, which require high power.

SUMMARY

Embodiments are directed to a battery module.

The embodiments may be realized by providing a battery module including a plurality of battery cells arranged in one direction; heat insulating members interposed between the plurality of battery cells so as to control heat generated in the battery cells; and a housing fixing the battery cells and the heat insulating members.

Each of the heat insulating members may have a thickness of about 0.5 mm to about 2 mm.

Each of the heat insulating members may have a thermal conductivity of about 0.01 W/mK to about 0.5 W/mK.

Each of the heat insulating members may include a fiber sheet.

Each of the heat insulating members may include a vulcanized fiber sheet, the vulcanized fiber sheet being formed of cotton fiber or pulp fiber and cellulose.

Each of the heat insulating members has a size corresponding to a size of a wide surface of an adjoining battery cell of the plurality of battery cells.

Each of the heat insulating members may include a base portion on a wide surface of an adjoining battery cell of the plurality of battery cells, and first and second side portions respectively bent at end portions of the base portion.

The first and second side portions may have a size corresponding to a size of a side surface of the adjoining battery cell.

The heat insulating members may include first and second heat insulating members adjacent to each other, and ends of the first and second side portions of the first heat insulating member may respectively contact end portions of the base portion of the second heat insulating member.

Each of the heat insulating members may have a size corresponding to a size of a wide surface of an adjoining battery cell of the plurality of battery cells, and may include an inwardly recessed central portion and an edge surrounding the central portion.

The central portion of each heat insulating member may have a rounded section, and the edge of the heat insulating member may have a flat section.

The housing may include a pair of end plates disposed opposite to each other at an outside of the plurality of battery cells arranged in the one direction, and a pair of connection plates connecting the pair of end plates.

The heat insulating members may be further provided between each end plate and battery cells at ends of the plurality of battery cell arranged in the one direction.

DETAILED DESCRIPTION

In the drawing figures, the dimensions of layers and regions may be exaggerated for clarity of illustration. It will also be understood that when a layer or element is referred to as being “on” another element, it can be directly on the other element, or intervening elements may also be present. In addition, it will also 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. Like reference numerals refer to like elements throughout.

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

The battery module100according to this embodiment may include a plurality of battery cells10arranged in one direction; thermal insulating members150interposed between the plurality of battery cells10so as to control heat generated from the battery cells10; and a housing18and19fixing the battery cells10and the thermal insulating members150.

The battery cell10may include a battery case, and an electrode assembly and an electrolyte (not illustrated), which are accommodated in the battery case. The electrode assembly may include a positive electrode plate, a negative electrode plate, and a separator interposed between the electrode plates. The electrode assembly and the electrolyte may react with each other to generate electrochemical energy. The battery case may be sealed with a cap assembly14, and the cap assembly14may be provided with positive and negative electrode terminals11and12having different polarities, and a vent13. The vent13is a safety means and may act as a passage along or through which gas generated inside the battery cell10is exhausted to the outside of the battery cell10. The positive and negative electrode terminals11and12of adjacent battery cells10may be electrically connected to each other through a bus-bar15, and the bus-bar15may be fixed by a nut16or the like.

The battery module100may be used as one power source, using the housing18and19accommodating the plurality of battery cells10therein. The housing18and19may include a pair of end plates18disposed opposite to each other at an outside of, e.g., outer ends of, the battery cells10, and a pair of connection plates19connecting the pair of end plates18to each other. The plurality of battery cells10may be arranged in the one direction so that wide surfaces of the battery cells10are opposite to or facing each other, and the pair of end plates18may be provided on outermost surfaces of the arranged battery cells10, respectively. In this case, the heat insulating member150may be further provided between the end plate18and the battery cells10at ends of the arranged group of battery cells10.

Generally, a battery module includes a plurality of battery cells, and the battery cells may generate a large amount of heat while being charged/discharged. The heat may cause thermal runaway in the battery cell, and therefore, the separator of the electrode assembly in the battery cell may be melted. The melted separator may cause direct contact between positive and negative electrode plates, thereby resulting in a short circuit in the battery cell. Accordingly, the heat generated in the battery cell may be transferred to an adjacent battery cell, and thus, the arranged battery cells may consecutively malfunction and/or explode. In the process of assembling the battery module, metallic foreign matter (which may be difficult to see with the naked eye) may be frequently inserted between the battery cells. Therefore, scratches may be produced on the surface of the battery cell due to vibration or impact in the use of the battery module. The scratches may cause insulation breakdown on a surface of the battery cell, and therefore, a short circuit in the battery cells may occur.

In the battery module according to this embodiment, a heat insulating member150may be interposed between adjacent battery cells10. The heat insulating member150may help reduce and/or prevent high-temperature or heat generated in the battery cell from being transferred to an adjacent battery cell10. The heat insulating member150may be strong or resistant against vibration or impact. Thus, the heat insulating member150may effectively maintain the insulation between surfaces of the battery cells10, which may otherwise be broken by metallic foreign matter that finds its way between the battery cells10.

FIG. 3illustrates a perspective view showing the battery cells and the heat insulating members according to an embodiment.

Referring toFIG. 3, the heat insulating member150may be interposed between adjacent battery cells10, so as to help prevent the battery cells10from coming in direct contact with each other. In this case, the heat insulating member150may have a size corresponding to a size of a wide side surface of the battery cell10. For example, the heat insulating member150may have a size, i.e., length and width, that is the same as the size of the wide side surface of the battery cell10. Hereinafter, for convenience of illustration, the battery cells10arranged adjacent to each other are referred to as a first battery cell10aand a second battery cell10b.

A thickness t of the heat insulating member150may be about 0.5 mm to about 2 mm. Maintaining the thickness t of the heat insulating member150at about 0.5 mm or greater may help ensure that the heat insulating member150is able to sufficiently reduce and/or prevent thermal conduction between the first and second battery cells10aand10b. Thus, transfer of high-temperature heat from the first battery cell10ato the second battery cell10bmay be reduced and/or prevented. Therefore, the safety of the battery module may be ensured. In the process of manufacturing the battery module, the insulation on the surface of the battery cell may be easily broken by foreign matter that may find its way between the first and second battery cells10aand10b. Maintaining the thickness t of the heat insulating member150at about 2 mm or less may help ensure that the spacing distance between the first and second battery cells10aand10bis not undesirably increased. Thus, the volume of the battery module per unit capacity may not be undesirably increased.

A thermal conductivity of the heat insulating member150may be about 0.01 W/mK to about 0.5 W/mK. Maintaining the thermal conductivity of the heat insulating member150at about 0.01 W/mK or higher may help ensure that high-temperature heat generated in the first battery cell10ais not transferred to the second battery cell10bwithout the use of a high-priced material in the manufacturing of the heat insulating member150. Therefore, an unnecessary increase in the manufacturing cost of the heat insulating member150may be avoided. Maintaining the thermal conductivity of the heat insulating member150at about 0.5 W/mK or less may help reduce and/or prevent transfer of the heat generated in the first battery cell10ato the second battery cell10b.

In an implementation, the heat insulating member150may include a fiber sheet. The fiber sheet may be manufactured by providing a plurality of fiber-shaped materials to be entangled and compressing the materials. The fiber sheet may be provided with a large quantity of pores capable of capturing air therein. For example, the heat insulating member may include a vulcanized fiber sheet, and the vulcanized fiber sheet may be made of cotton fiber or pulp fiber and cellulose. The vulcanized fiber sheet may be manufactured by stacking and compressing the cotton fiber or pulp fiber and cellulose.

In an implementation, a cooling plate may be provided at a lower portion of the battery module, and a heat exchange medium, e.g., a coolant, may pass through an inside of the cooling plate. In this case, the coolant may perform a heat exchange with the bottom surface of the battery cell. Thus, the heat generated from each battery cell may be removed by the coolant.

Hereinafter, other embodiments will be described with reference toFIGS. 4 to 6B. Contents of these embodiments, except the following contents, may be similar to those of the embodiment described with reference toFIGS. 1 to 3, and therefore, repeated detailed descriptions may be omitted.

FIG. 4illustrates a partial exploded perspective view of a battery module according to another embodiment.FIG. 5illustrates a perspective view showing battery cells and heat insulating members according to the embodiment.

Referring toFIGS. 4 and 5, in the battery module200according to this embodiment, a plurality of battery cells10arranged in one direction may be fixed by a pair of end plates18and a pair of connection plates19. In this case, heat insulating members250may be interposed between the battery cells10. The heat insulating member250may include a base portion251(corresponding to a wide side surface of the battery cell10), and first and second side portions252and253respectively bent from end portions251aof the base portion251. The first and second side portions252and253may be provided to respectively cover narrow side surfaces of the battery cell10.

The heat insulating member250may help reduce and/or prevent the transfer of heat between adjacent first and second battery cells10aand10b, thereby improving the safety of the battery module200. Similarly, when the adjacent heat insulating members250are a first heat insulating member250aand a second heat insulating member250b, the battery cell10may be provided between the first and second heat insulating members250aand250b. In this embodiment, for convenience of illustration, the adjacent heat insulating members250are referred to as the first and second heat insulating members250aand250b, and the adjacent battery cells10are referred to as the first and second battery cells10aand10b.

The first heat insulating member250amay be provided on a front surface of the first battery cell10a, and the second heat insulating member250bmay be provided between the first and second battery cells10aand10b. In this case, the base portions251of the first and second heat insulating members250aand250bmay contact the wide side surfaces of the first and second battery cells10aand10b, and the first and second side portions252and253of the first and second heat insulating members250aand250bmay be provided to have a size corresponding to the narrow side surface of the battery cell10. Thus, ends of the first and second side portions252and253of the first heat insulating member250amay extend toward the second heat insulating member250a, so as to respectively contact both end portions251aof the base portion251of the second heat insulating member250b.

In the battery module200according to this embodiment, each of the heat insulating members250(interposed between the battery cells10arranged in the one direction) may cover the wide side surface of the battery cell10and both the narrow side surfaces of the battery cell10. Thus, the heat insulating member250may insulate heat generated from the battery cell10, so that it is possible to effectively prevent the heat from being transferred to the adjacent battery cells10.

FIG. 6Aillustrates a perspective view of a heat insulating member according to still another embodiment.FIG. 6Billustrates a sectional view taken along line A-A ofFIG. 6A.

Referring toFIGS. 6A and 6B, the heat insulating member350according to this embodiment may be interposed between adjacent battery cells so as to prevent high-temperature heat generated in any one battery cell from being transferred to other battery cells. The heat insulating member350may have a size corresponding to the wide side surface of the battery cell, i.e., the heat insulating member350may have a length and width about equal to the length and width of the wide surface of the battery cell. The heat insulating member350may include an inwardly recessed central portion351, and an edge252surrounding the central portion351. The central portion351of the heat insulating member350may have a round section, and the edge352of the heat insulating member350may have a flat section. For example, when viewed in cross section, as inFIG. 6B, the central portion351may have a rounded shape, and the edge portion352may have a flat or rectangular shape. In an implementation, the inwardly recessed central portion351may have a rounded, concave recess that is recessed from the flat outer surface of the edge portion352.

The battery cells may generate gas as a side reaction while being charged/discharged a plurality of times. The gas may swell the battery cells. In this case, the battery cell may be swelled so that a central region of the battery cell may protrude outwardly due to the structural characteristics of the battery cell. In the heat insulating member350according to this embodiment, the central portion351(that is a portion corresponding to the swelled portion of the battery cell) may have the round section or rounded cross section. Thus, in a case where the battery cell is swelled, the central portion351may provide a space corresponding to the swelled central region of the battery cell, so that it is possible to reduce the likelihood and/or prevent an entire shape of the battery module from being changed. Further, an external shape of corner sides of the battery cell may hardly be changed. Thus, the corner sides of the battery cell may be stably fixed by the edge352of the heat insulating member350. In an implementation, the central portion351may have a rounded, e.g., circular, shape. In an implementation, the edge352of the heat insulating member350may surround the central portion351and may form a rectangular outer shape of the heat insulating member350. For example, outer dimensions of the edge portion352forming rectangular outer shape of the heat insulating member350may correspond with, i.e., may be about equal to, a size and shape or dimensions of a corresponding one of the battery cells.

By way of summation and review, an electrochemical reaction occurs in a battery cell, and heat may be generated as the electrochemical reaction proceeds. The heat generated as described above may cause the battery cell to be deteriorated, thereby lowering the reliability of the battery cell. For example, in a high-capacity battery cell, the amount of heat generated in the battery cell may be further increased. Such an occurrence may be likely in a battery module including a set of battery cells, which may result in fire, explosion, or the like.

The embodiments provide a battery module having improved safety.

The embodiments provide a battery module having improved safety using a new member.

The embodiments also provide a battery module for effectively controlling heat generated in a plurality of battery cells.