Patent Description:
Referring to <FIG>, in a battery module to which a <NUM>-plate structure where a main housing <NUM> of the battery module is made of four plates is applied, a plurality of battery cells <NUM> accommodated in the main housing <NUM> are typically pouch -type battery cells.

The pouch-type battery cell <NUM> has a soft characteristic, and due to this characteristic, an electrolyte is collected downward due to gravity while the battery cell <NUM> is stored, and thus a lower portion of the battery cell <NUM> may be relatively thicker.

If the battery cell <NUM> is formed to have a greater thickness at the portion thereof as described above, the side plate <NUM> may be inclined when the cell stack is pressed through the side plate <NUM>. If the side plate <NUM> is pressed in an inclined state, the position of each battery cell <NUM> of 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 housing <NUM>, the bus bar frame is also inserted, and thus the bus bar frame made of resin may prevent the side plate <NUM> from being inclined to some extent. In addition, since an insulation pad <NUM> made of a material with elasticity is inserted between the cell stack and the side plate <NUM>, the inclination of the side plate <NUM> may be prevented to some extent.

However, since a gap may also be created between the bus bar frame and the side plate <NUM> according to a design tolerance, when the side portion of the cell stack is pressed using the side plate <NUM>, it is not possible to perfectly prevent the side plate <NUM> from being tilted.

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

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.

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 the other side of the cell stack in a longitudinal direction; a housing configured to accommodate a combined body of the cell stack and the bus bar frame so that the bus bar frame is exposed out; 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 the bus bar frame and the inner surface of the housing.

The housing includes 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 both 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 both side ends of the upper cover portion to face the side surface 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 both side ends of the lower cover portion to face the side surface of the cell stack.

The side plate may be interposed between the insulation pad and the upper fixing portion and between the insulation pad and the lower fixing portion.

The cell stack may be inserted into the housing in a state where both side portions thereof are pressed, and the insulation pad may press the side plate outward by an elastic restoring force thereof caused by pressing the cell stack so that the side plate comes into close contact with the upper fixing portion and the lower fixing portion.

The insulation pad includes a cell support interposed between the cell stack and the side plate; and a frame support configured to extend from the cell support and interposed between the bus bar frame and the side plate.

The bus bar frame has an insert portion that is inserted into the housing. The frame support of the insulation pad is interposed in an elastically pressurized state between the insert portion of the bus bar frame and the side plate.

A surface of the insert portion of the bus bar frame and a surface of the frame support of the insulation pad, which face each other, may have a tapered shape to 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.

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.

Therefore, the description proposed herein is just a preferable example for the purpose of illustrations only, not intended to limit the scope of the disclosure, so it should be understood that other modifications could be made thereto without departing from the scope of the disclosure.

Referring to <FIG>, a battery module according to an embodiment of the present disclosure is implemented to include a cell stack <NUM>, an insulation pad <NUM>, a bus bar frame <NUM> and a housing <NUM>.

Referring to <FIG>, the cell stack <NUM> includes a plurality of battery cells <NUM> stacked on each other such that their wide surfaces face each other. The insulation pad <NUM> is provided to outermost sides at both sides of the cell stack <NUM>. That is, the cell stack <NUM> is accommodated in the housing <NUM>, and, at this time, in order to minimize the volume of the cell stack <NUM> and allow the cell stack <NUM> to be easily inserted, the insulation pad <NUM> made of an elastic and insulating material such as a sponge is disposed at the outermost sides of both sides of the cell stack <NUM>.

In addition, the insulation pad <NUM> may be additionally interposed between the battery cells <NUM> adjacent to each other.

As the battery cell <NUM>, a pouch-type battery cell may be applied. Referring to <FIG>, the pouch-type battery cell <NUM> includes an electrode assembly (not shown), a pair of electrode leads <NUM>, and a cell case <NUM>.

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 leads <NUM> are connected to a positive electrode tab (not shown) and a negative electrode tab (not shown), respectively, and are drawn out of the cell case <NUM>. The pair of electrode leads <NUM> are drawn out at one longitudinal side and the other longitudinal side of the battery cell <NUM>, respectively. That is, the battery cell <NUM> applied 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 case <NUM> includes two regions, namely an accommodation portion 112a accommodating the electrode assembly and a sealing portion 112b extending in a circumferential direction of the accommodation portion 112a and thermally fused in a state where the electrode lead <NUM> is drawn out to seal the cell case <NUM>.

Although not shown in the figures, the cell case <NUM> is 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 to <FIG> again, the bus bar frame <NUM> is a component for covering one side and the other side of the cell stack <NUM> in a longitudinal direction (a direction parallel to the Y axis, based on <FIG>), and has a plurality of lead slits S so that the electrode leads <NUM> extending at both longitudinal sides of the cell stack <NUM> may be drawn out of the battery module.

The bus bar frame <NUM> includes a plurality of bus bars <NUM> and a pair of module terminals <NUM>. The bus bar <NUM> is placed on an outer surface of the bus bar frame <NUM> and is coupled to the electrode lead drawn out through the lead slit S by welding. The pair of electrode leads <NUM> drawn out from different battery cells <NUM> may be coupled to one bus bar <NUM>, and thus the battery cells <NUM> may be electrically connected.

The pair of module terminals <NUM> are located at both side ends of the battery module in a width direction (a direction parallel to the X axis, based on <FIG>). The module terminal <NUM> is coupled to the electrode lead <NUM> drawn out from the battery cell <NUM> disposed at an outermost side of the cell stack <NUM> by welding. One of the pair of module terminals <NUM> is connected to the positive electrode lead, and the other is connected to the negative electrode lead.

Referring to <FIG> along with <FIG>, the housing <NUM> is a component for accommodating the cell stack <NUM> and the insulation pad <NUM> therein, and includes an upper housing <NUM>, a lower housing <NUM> and a pair of side plates <NUM>.

The upper housing <NUM> includes an upper cover portion <NUM> configured to face the upper surface of the cell stack <NUM> and a pair of upper fixing portions <NUM> bent approximately vertically from both side ends of the upper cover portion <NUM> in a longitudinal direction (a direction parallel to the X axis, based on <FIG>) to face the side surface of the cell stack <NUM>.

The lower housing <NUM> includes a lower cover portion <NUM> configured to face the lower surface of the cell stack <NUM> and a pair of lower fixing portions <NUM> bent approximately vertically from both side ends of the lower cover portion <NUM> in a longitudinal direction (a direction parallel to the X axis, based on <FIG>) to face the side surface of the cell stack <NUM>.

The side plate <NUM> covers the outer surface of the insulation pad <NUM>. One side of the side plate <NUM> in the longitudinal direction (a direction parallel to the Z axis, based on <FIG>) is interposed between the insulation pad <NUM> and the upper fixing portion <NUM>, and the other side of the side plate <NUM> in the longitudinal direction (a direction parallel to the X-axis, based on <FIG>) is interposed between the insulation pad <NUM> and the lower fixing portion <NUM>.

Due to the structure of the housing <NUM> as above, the cell stack <NUM> is inserted into the housing <NUM> in a state where both side portions thereof in a width direction (a direction parallel to the X axis, based on <FIG>) are pressed. At this time, the insulation pad <NUM> presses the side plate <NUM> outward by its elastic restoring force caused by pressing the cell stack <NUM>. Therefore, the side plate <NUM> comes into close contact with the upper fixing portion <NUM> and the lower fixing portion <NUM>.

The upper housing <NUM> and the side plate <NUM> may be coupled to each other by performing a welding operation through the outer surface of the upper fixing portion <NUM> in a state where the side plate <NUM> is in close contact with the upper fixing portion <NUM>.

Similarly, the lower housing <NUM> and the side plate <NUM> may be coupled to each other by performing a welding operation through the outer surface of the lower fixing portion <NUM> in a state where the side plate <NUM> is in close contact with the lower fixing portion <NUM>.

Next, referring to <FIG> and <FIG>, the insulation pad <NUM> is interposed not only between the side surface of the cell stack <NUM> and the inner surface of the housing <NUM> but also between the side surface of the bus bar frame <NUM> and the inner surface of the housing <NUM>.

That is, the insulation pad <NUM> includes a cell support <NUM> interposed between the cell stack <NUM> and the side plate <NUM> and a frame support <NUM> extending from the cell support <NUM> and interposed between the bus bar frame <NUM> and the side plate <NUM>.

The names of the cell support <NUM> and the frame support <NUM> are defined differently according to their positions, and the cell support <NUM> and the frame support <NUM> are connected to each other to form an integral insulation pad <NUM>.

The frame support <NUM> is interposed in an elastically pressurized state between the insert portion <NUM> of the bus bar frame <NUM>, which corresponding to a portion inserted into the housing <NUM>, and the side plate <NUM>, and thus, even if the shape of the cell stack <NUM> is deformed, it is possible to prevent the side plate <NUM> from being inclined.

Meanwhile, the bus bar frame <NUM> may be inserted into the housing <NUM> after a process of accommodating the cell stack <NUM> and the insulation pad <NUM> in the housing in a state where both side portions of the cell stack <NUM> in the width direction are pressed by the insulation pad <NUM> and a process of coupling the upper housing <NUM> and the lower housing <NUM> to the side plate <NUM> by welding. When following this process sequence, it may not be easy to push the insert portion <NUM> of the bus bar frame <NUM> into the housing <NUM> due to the frame support <NUM> of the insulation pad <NUM>.

Referring to <FIG>, the frame support <NUM> may have a form different from that shown in <FIG> to facilitate the insertion of the insert portion <NUM>. In the battery module shown in <FIG>, a surface of the insert portion <NUM> of the bus bar frame <NUM> and a surface of the frame support <NUM> of the insulation pad <NUM>, which face each other, have a shape parallel to the extending direction of the cell support <NUM> of the insulation pad <NUM>. However, in the battery module shown in <FIG>, the surface of the insert portion <NUM> of the bus bar frame <NUM> and the surface of the frame support <NUM> of the insulation pad <NUM>, which face each other, have a tapered shape to form a predetermined angle with respect to the extending direction of the cell support <NUM> of the insulation pad <NUM>.

Claim 1:
A battery module, comprising:
a cell stack (<NUM>) in which a plurality of battery cells (<NUM>) are stacked;
a pair of bus bar frames (<NUM>) configured to cover one side and the other side of the cell stack (<NUM>) in a longitudinal direction;
a housing (<NUM>) configured to accommodate a combined body of the cell stack (<NUM>) and the bus bar frame (<NUM>) so that the bus bar frame (<NUM>) is exposed out; and
an insulation pad (<NUM>) interposed between a side surface of the cell stack (<NUM>) and an inner surface of the housing (<NUM>) and between a side surface of the bus bar frame (<NUM>) and the inner surface of the housing (<NUM>),
wherein the bus bar frame (<NUM>) has an insert portion (<NUM>) that is inserted into the housing (<NUM>),
wherein the housing (<NUM>) includes:
an upper housing (<NUM>) configured to cover an upper portion of the cell stack (<NUM>);
a lower housing (<NUM>) configured to cover a lower portion of the cell stack (<NUM>); and
a pair of side plates (<NUM>) configured to cover both side portions of the cell stack (<NUM>)
wherein the insulation pad (<NUM>) includes:
a cell support (<NUM>) interposed between the cell stack (<NUM>) and the side plate (<NUM>); and
a frame support (<NUM>) configured to extend from the cell support (<NUM>) and interposed between the bus bar frame (<NUM>) and the side plate (<NUM>) and interposed in an elastically pressurized state between the insert portion (<NUM>) of the bus bar frame (<NUM>) and the side plate (<NUM>).