Battery Module Having Insulation Pad With Extended Length, and Battery Pack and Vehicle Comprising Same

A battery module includes a cell stack in which a plurality of battery cells are stacked; a pair of bus bar frames configured to cover one side and another side, respectively, of the cell stack in a longitudinal direction; a housing configured to accommodate a combined body of the cell stack and the pair of bus bar frames so that the pair of bus bar frames is exposed to an outside of the housing; and an insulation pad interposed between a side surface of the cell stack and an inner surface of the housing and between a side surface of one of the pair of bus bar frames and the inner surface of the housing.

TECHNICAL FIELD

The present disclosure relates to a battery module having an insulation pad with an extended length, and a battery pack and a vehicle including the battery module, and more specifically, to a battery module having an insulation pad interposed between an outer surface of a cell stack and a side plate in which a length of the insulation pad is extended to be also interposed between a bus bar frame and the side plate, and a battery pack and a vehicle including the battery module.

BACKGROUND ART

Referring toFIGS. 1 and 2, in a battery module to which a 4-plate structure where a main housing2of the battery module is made of four plates is applied, a plurality of battery cells1accommodated in the main housing2are typically pouch-type battery cells.

The pouch-type battery cell1has a soft characteristic, and due to this characteristic, an electrolyte is collected downward due to gravity while the battery cell1is stored, and thus a lower portion of the battery cell1may be relatively thicker.

If the battery cell1is formed to have a greater thickness at the portion thereof as described above, the side plate3may be inclined when the cell stack is pressed through the side plate3. If the side plate3is pressed in an inclined state, the position of each battery cell1of the cell stack may be changed from its initial design, and, in this case, the positional relationship with bus bar frames respectively coupled to front and rear surfaces of the cell stack may also be changed from the original design.

This may result in a failure of a welding portion by accumulating fatigue at the welding portion between a bus bar provided to the bus bar frame and an electrode lead of the battery cell, thereby causing a product failure of the battery module.

When the cell stack is inserted into the main housing2, the bus bar frame is also inserted, and thus the bus bar frame made of resin may prevent the side plate3from being inclined to some extent. In addition, since an insulation pad4made of a material with elasticity is inserted between the cell stack and the side plate3, the inclination of the side plate3may be prevented to some extent.

However, since a gap may also be created between the bus bar frame and the side plate3according to a design tolerance, when the side portion of the cell stack is pressed using the side plate3, it is not possible to perfectly prevent the side plate3from being tilted.

Accordingly, there is a need to develop a battery module having a structure for preventing the side plate3from being tilted without significantly changing the structure of the existing battery module.

DISCLOSURE

Technical Problem

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, which may prevent a side plate from being inclined when a cell stack is pressed using a side plate and thus allow the cell stack to be pressed horizontally at both side portions thereof.

However, the technical problem to be solved by the present disclosure is not limited to the above, and other objects not mentioned herein will be understood from the following description by those skilled in the art.

Technical Solution

In one aspect of the present disclosure, there is provided a battery module, comprising: a cell stack in which a plurality of battery cells are stacked; a pair of bus bar frames configured to cover one side and another side, respectively, of the cell stack in a longitudinal direction; a housing configured to accommodate a combined body of the cell stack and the pair of bus bar frames so that the pair of bus bar frames is exposed to an outside of the housing; and an insulation pad interposed between a side surface of the cell stack and an inner surface of the housing and between a side surface of one of the pair of bus bar frames and the inner surface of the housing.

The housing may include an upper housing configured to cover an upper portion of the cell stack; a lower housing configured to cover a lower portion of the cell stack; and a pair of side plates configured to cover respective side portions of the cell stack.

The upper housing may include an upper cover portion configured to face an upper surface of the cell stack and a pair of upper fixing portions bent vertically from opposing side ends of the upper cover portion to face respective side surfaces of the cell stack, and the lower housing may include a lower cover portion configured to face a lower surface of the cell stack and a pair of lower fixing portions bent vertically from opposing side ends of the lower cover portion to face the respective side surfaces of the cell stack.

One of the pair of side plates may be interposed between the insulation pad and one of the pair of upper fixing portions and between the insulation pad and one of the pair of lower fixing portions.

The insulation pad may press the one of the pair of side plates outward by an elastic restoring force thereof so that the one of the pair of side plates comes into contact with the one of the pair of upper fixing portions and the one of the pair of lower fixing portions.

The insulation pad may include a cell support interposed between the cell stack and one of the pair of side plates; and a frame support configured to extend from the cell support and interposed between the one of the pair of bus bar frames and the one of the pair of side plates.

The one of the pair of bus bar frames may have an insert portion that is inserted into the housing.

A surface of the insert portion of the one of the pair of bus bar frames and a surface of the frame support of the insulation pad, which face each other, may have respective tapered shapes to each form a predetermined angle with respect to an extending direction of the cell support of the insulation pad.

In another aspect of the present disclosure, there are also provided a battery pack and a vehicle, which comprises the battery module according to an embodiment the present disclosure.

Advantageous Effects

According to an embodiment of the present disclosure, it is possible to prevent a side plate from being inclined when a cell stack is pressed using a side plate, and thus the cell stack may be pressed horizontally at both side portions thereof.

BEST MODE

Referring toFIGS. 3 and 4, a battery module according to an embodiment of the present disclosure is implemented to include a cell stack100, an insulation pad200, a bus bar frame300and a housing400.

Referring toFIG. 4, the cell stack100includes a plurality of battery cells110stacked on each other such that their wide surfaces face each other. The insulation pad200is provided to outermost sides at both sides of the cell stack100. That is, the cell stack100is accommodated in the housing400, and, at this time, in order to minimize the volume of the cell stack100and allow the cell stack100to be easily inserted, the insulation pad200made of an elastic and insulating material such as a sponge is disposed at the outermost sides of both sides of the cell stack100.

In addition, the insulation pad200may be additionally interposed between the battery cells110adjacent to each other.

As the battery cell110, a pouch-type battery cell may be applied. Referring toFIG. 5, the pouch-type battery cell110includes an electrode assembly (not shown), a pair of electrode leads111, and a cell case112.

Although not shown in the drawings, the electrode assembly has a form in which separators are interposed between positive electrode plates and negative electrode plates that are repeatedly stacked alternately, and separators are preferably positioned at both outermost sides for insulation, respectively.

The positive electrode plate includes a positive electrode current collector and a positive electrode active material layer coated on one side of the positive electrode current collector, and a positive electrode uncoated region not coated with a positive electrode active material is formed at one side end of the positive electrode plate. The positive electrode uncoated region functions as a positive electrode tab.

The negative electrode plate may include a negative electrode current collector and a negative electrode active material layer coated on one surface or both sides of the negative electrode current collector, and a negative electrode uncoated region not coated with a negative electrode active material is formed at one side end of the negative electrode plate. The negative electrode uncoated region functions as a negative electrode tab.

In addition, the separator is interposed between the positive electrode plate and the negative electrode plate to prevent electrode plates having different polarities from directly contacting each other. The separator may made of a porous material so that ions may be moved using the electrolyte as a medium between the positive electrode plate and the negative electrode plate.

The pair of electrode leads111are connected to a positive electrode tab (not shown) and a negative electrode tab (not shown), respectively, and are drawn out of the cell case112. The pair of electrode leads111are drawn out at one longitudinal side and the other longitudinal side of the battery cell110, respectively. That is, the battery cell110applied to the present disclosure corresponds to a bidirectional drawing-type battery cell in which the positive electrode lead and the negative electrode lead are drawn in opposite directions.

The cell case112includes two regions, namely an accommodation portion112aaccommodating the electrode assembly and a sealing portion112bextending in a circumferential direction of the accommodation portion112aand thermally fused in a state where the electrode lead111is drawn out to seal the cell case112.

Although not shown in the figures, the cell case112is sealed by affixing and thermally fusing edge portions of an upper case and a lower case made of a multi-layered pouch film in which a resin layer, a metal layer and a resin layer are stacked in order.

Referring toFIGS. 3 and 4again, the bus bar frame300is a component for covering one side and the other side of the cell stack100in a longitudinal direction (a direction parallel to the Y axis, based onFIGS. 3 and 4), and has a plurality of lead slits S so that the electrode leads111extending at both longitudinal sides of the cell stack100may be drawn out of the battery module.

The bus bar frame300includes a plurality of bus bars310and a pair of module terminals320. The bus bar310is placed on an outer surface of the bus bar frame300and is coupled to the electrode lead drawn out through the lead slit S by welding. The pair of electrode leads111drawn out from different battery cells110may be coupled to one bus bar310, and thus the battery cells110may be electrically connected.

The pair of module terminals320are located at both side ends of the battery module in a width direction (a direction parallel to the X axis, based onFIG. 3). The module terminal320is coupled to the electrode lead111drawn out from the battery cell110disposed at an outermost side of the cell stack100by welding. One of the pair of module terminals320is connected to the positive electrode lead, and the other is connected to the negative electrode lead.

Referring toFIGS. 6 and 7along withFIG. 3, the housing400is a component for accommodating the cell stack100and the insulation pad200therein, and includes an upper housing410, a lower housing420and a pair of side plates430.

The upper housing410includes an upper cover portion411configured to face the upper surface of the cell stack100and a pair of upper fixing portions412bent approximately vertically from both side ends of the upper cover portion411in a longitudinal direction (a direction parallel to the X axis, based onFIGS. 6 and 7) to face the side surface of the cell stack100.

The lower housing420includes a lower cover portion421configured to face the lower surface of the cell stack100and a pair of lower fixing portions422bent approximately vertically from both side ends of the lower cover portion421in a longitudinal direction (a direction parallel to the X axis, based onFIGS. 6 and 7) to face the side surface of the cell stack100.

The side plate430covers the outer surface of the insulation pad200. One side of the side plate430in the longitudinal direction (a direction parallel to the Z axis, based onFIGS. 6 and 7) is interposed between the insulation pad200and the upper fixing portion412, and the other side of the side plate430in the longitudinal direction is interposed between the insulation pad200and the lower fixing portion422.

Due to the structure of the housing400as above, the cell stack100is inserted into the housing400in a state where both side portions thereof in a width direction (a direction parallel to the X axis, based onFIGS. 6 and 7) are pressed. At this time, the insulation pad200presses the side plate430outward by its elastic restoring force caused by pressing the cell stack100. Therefore, the side plate430comes into close contact with the upper fixing portion412and the lower fixing portion422.

The upper housing410and the side plate430may be coupled to each other by performing a welding operation through the outer surface of the upper fixing portion412in a state where the side plate430is in close contact with the upper fixing portion412.

Similarly, the lower housing420and the side plate430may be coupled to each other by performing a welding operation through the outer surface of the lower fixing portion422in a state where the side plate430is in close contact with the lower fixing portion422.

Next, referring toFIGS. 8 and 9, the insulation pad200is interposed not only between the side surface of the cell stack100and the inner surface of the housing400but also between the side surface of the bus bar frame300and the inner surface of the housing400.

That is, the insulation pad200includes a cell support210interposed between the cell stack100and the side plate330and a frame support220extending from the cell support210and interposed between the bus bar frame300and the side plate330.

The names of the cell support210and the frame support220are defined differently according to their positions, and the cell support210and the frame support220are connected to each other to form an integral insulation pad200.

The frame support220is interposed in an elastically pressurized state between the insert portion330of the bus bar frame300, which corresponding to a portion inserted into the housing400, and the side plate430, and thus, even if the shape of the cell stack100is deformed, it is possible to prevent the side plate430from being inclined.

Meanwhile, the bus bar frame300may be inserted into the housing400after a process of accommodating the cell stack100and the insulation pad200in the housing in a state where both side portions of the cell stack100in the width direction are pressed by the insulation pad200and a process of coupling the upper housing410and the lower housing420to the side plate430by welding. When following this process sequence, it may not be easy to push the insert portion330of the bus bar frame300into the housing400due to the frame support220of the insulation pad200.

Referring toFIG. 10, the frame support220may have a form different from that shown inFIG. 9to facilitate the insertion of the insert portion330. In the battery module shown inFIG. 9, a surface of the insert portion330of the bus bar frame300and a surface of the frame support220of the insulation pad200, which face each other, have a shape parallel to the extending direction of the cell support210of the insulation pad200. However, in the battery module shown inFIG. 10, the surface of the insert portion330of the bus bar frame300and the surface of the frame support220of the insulation pad200, which face each other, have a tapered shape to form a predetermined angle with respect to the extending direction of the cell support210of the insulation pad200.

If the battery module according to an embodiment of the present disclosure has a structure as shown inFIG. 10, the width of the entrance is widened when the bus bar frame300is inserted, thereby allowing more convenient insertion.