Patent Description:
Secondary batteries that can be charged and discharged so as to be repeatedly used, include one battery cell so as to be used in portable small electronic devices, such as mobile phones, laptop computers, computers, cameras, and camcorders, or include a battery pack including a plurality of battery cells so as to be used as a power source for driving a motor of a high-output hybrid electric vehicle (HEV) or electric vehicle (EV).

A battery used in the HEV or EV is required to realize high output and high capacity. For this reason, a plurality of batteries are configured as a battery pack in one unit, and a plurality of such battery packs are electrically connected in series or in parallel to operate as a large capacity and high output power source.

Meanwhile, due to the characteristics of the HEV or EV, the battery pack provided therein has to be fixed so as not to be arbitrarily removed due to vibration or the like. Such a battery pack is provided as a sub-assembly of a battery cell called a module, and such an assembly is formed by combining various component parts, thereby acting as a main factor that increases the cost and weight of the battery pack. Also, in such a battery pack, the lifespan and safety of the battery cells are important, and proper temperature maintenance is essential for this. In particular, in the case of an air cooling type battery pack, the key is whether the path of the air cooling type battery pack can cool the front side of the battery cell.

<CIT> discloses a car power source apparatus having a battery block having a plurality of connected batteries, a battery state detection section connected to the battery block, a base-plate having the battery state detection section and battery block mounted on top, a cover-plate that closes-off the top of the base-plate, and side-plates that close-off the open regions between the cover-plate and base-plate at both ends. The cover-plate is provided with a top cover that establishes the battery holding region inside, and an electronic component cover that establishes the electronic component compartment inside. The edges at both ends of the cover-plate have end edge-covers that extend downward from the side-plate top surfaces down the outer surfaces. The end edge-covers make the connection between the cover-plate and the side-plates a water-tight structure.

<CIT> a discloses a battery pack including a case in which a plurality of batteries are received; an electrode tab to connect the batteries to form one unit; and a data wire having a first end connected to the electrode tab, to act as a signal transmitting line of the plurality of batteries.

Provided is a structure of a battery pack, which has a reduced number of embedded components so as to have reduced cost and weight and has an efficiently adjusted internal temperature so as to have improved performance and stability.

According to an aspect, there is provided a battery pack as set out in claim <NUM>.

According to an embodiment of the present disclosure having the above-described structure, a battery pack, which has a reduced number of embedded components so as to have reduced cost and weight and has an efficiently adjusted internal temperature so as to have improved performance and stability, may be implemented. The scope of the present disclosure is not limited by these effects.

Furthermore, the effects of the present disclosure may be derived from the contents described below with reference to the drawings, in addition to the above-described contents.

As the present disclosure allows for various changes and numerous embodiments, particular embodiments will be illustrated in the drawings and described in detail in the written description. The effects and features of the present disclosure, and ways to achieve them will become apparent by referring to embodiments that will be described later in detail with reference to the drawings. However, the present disclosure is not limited to the following embodiments but may be embodied in various forms.

Hereinafter, embodiments of the present disclosure will be described below in more detail with reference to the accompanying drawings. Those components that are the same or are in correspondence are rendered the same reference numeral regardless of the figure number, and a redundant description therewith is omitted.

It will be understood that although the terms "first," "second," etc. may be used herein to describe various components, these components should not be limited by these terms.

It will be further understood that the terms "comprises" and/or "comprising" used herein specify the presence of stated features or components, but do not preclude the presence or addition of one or more other features or components.

It will be understood that when a layer, region, or component is referred to as being "formed on," another layer, region, or component, it may be directly or indirectly formed on the other layer, region, or component. That is, for example, intervening layers, regions, or components may be present.

In the following embodiments, the x-axis, the y-axis and the z-axis are not limited to three axes of the rectangular coordinate system, and may be interpreted in a broader sense. For example, the x-axis, the y-axis, and the z-axis may be perpendicular to one another, or may represent different directions that are not perpendicular to one another.

Sizes of elements in the drawings may be exaggerated for convenience of explanation. In other words, since sizes and thicknesses of components in the drawings are arbitrarily illustrated for convenience of explanation, the following embodiments are not limited thereto.

<FIG> is a perspective view schematically illustrating a battery pack according to an embodiment, and <FIG> is an enlarged perspective view schematically illustrating the battery pack of <FIG>.

Referring to <FIG> and <FIG>, the battery pack according to an embodiment of the present disclosure includes a lower case <NUM> including a first lower side wall <NUM> extending from a bottom surface <NUM>, a second lower side wall <NUM> and a third lower side wall <NUM>, an upper case <NUM> arranged to face the lower case <NUM>, and a battery unit <NUM> accommodated in the lower case <NUM>, sealed by the upper case <NUM> and including a plurality of battery cells <NUM>.

The lower case <NUM> and the upper case <NUM> may have an approximately hexahedral shape so as to accommodate the battery unit <NUM> and may be arranged to face each other. The lower case <NUM> and the upper case <NUM> may be coupled to each other via a fastening member <NUM>.

A sealing member <NUM> may be further between the upper case <NUM> and the lower case <NUM>. The sealing member <NUM> having a closed loop shape may be inserted into a groove 180a formed at a top end of the lower case <NUM>. The sealing member <NUM> may seal between the lower case <NUM> and the upper case <NUM>.

The lower case <NUM> includes the bottom surface <NUM>, the first lower side wall <NUM> connected to the bottom surface <NUM>, the second lower side wall <NUM>, and the third lower side wall <NUM>. The bottom surface <NUM> having a rectangular shape may include long sides and short sides. The first lower side wall <NUM> may extend from one long side of the bottom surface <NUM> in a +z-direction, and the second lower side wall <NUM> and the third lower side wall <NUM> respectively may extend in the +z-direction from one short side and the other short side of the bottom surface <NUM>. The second lower side wall <NUM> and the third lower side wall <NUM> are arranged to face each other. Referring to <FIG>, the bottom surface <NUM> may be arranged in parallel with an x-y plane. The lower side wall <NUM> may be arranged in parallel with an x-z plane, and the second and third lower side walls <NUM> and <NUM> may be arranged in parallel with a z-y plane.

Meanwhile, in the present embodiment, one side of the lower case <NUM> has an open shape. The lower case <NUM> has a structure in which three surfaces of the lower case <NUM> are surrounded by the first lower side wall <NUM>, the second lower side wall <NUM> and the third lower side wall <NUM>, and at least part of a side of the lower case <NUM> facing the first lower side wall <NUM> has an open shape. The battery unit <NUM> may be easily mounted on the lower case <NUM> through one open side of the lower case <NUM>. The side of the lower case <NUM> of <FIG> facing the first lower side wall <NUM> is entirely open.

The upper case <NUM> may be arranged to face the lower case <NUM> with the battery unit <NUM> therebetween. As shown in <FIG>, a shape in which the lower case <NUM> and the upper case <NUM> are coupled to each other, may have an overall hexahedral shape.

The upper case <NUM> includes a top surface <NUM>, a first upper side wall <NUM>, a second upper side wall <NUM>, a third upper side wall <NUM>, and a fourth upper side wall <NUM>, which extend from the top surface <NUM> in a -z-direction. The top surface <NUM> may be in parallel with the bottom surface <NUM> of the lower case <NUM> and may have an overall the same shape as the bottom surface <NUM> of the lower case <NUM>. Like in the bottom surface <NUM>, the top surface <NUM> having a rectangular shape may include long sides and short sides. The second upper side wall <NUM> may extend from one short side of the top surface <NUM> in the -z-direction, and the third upper side wall <NUM> may extend from the other short side of the top surface <NUM> in the -z-direction. The second upper side wall <NUM> and the third upper side wall <NUM> may be arranged to face each other.

Meanwhile, the first upper side wall <NUM> may extend from one long side of the top surface <NUM>, and the fourth upper side wall <NUM> may extend from the other long side of the top surface <NUM>. In the present embodiment, at least part of the first upper side wall <NUM> and the fourth upper side wall <NUM> are arranged to face each other. In this case, the first upper side wall <NUM> and the fourth upper side wall <NUM> face each other but may not entirely correspond to each other. That is, the length corresponding to a z-axis of the fourth upper side wall <NUM> may be greater than the length corresponding to the z-axis of the first upper side wall <NUM>.

First and second external terminals <NUM> and <NUM> may be located on the upper case <NUM>. The first and second external terminals <NUM> and <NUM> may be electrically connected to the battery unit <NUM> embedded in the cases <NUM> and <NUM>. A plurality of bus bars <NUM> may be electrically connected to the first and second external terminals <NUM> and <NUM>. The first and second external terminals <NUM> and <NUM> may be connected to electrodes of the plurality of battery cells <NUM> connected to a lead plate (not shown) through the plurality of bus bars <NUM>. For example, in the present embodiment, the first external terminal <NUM> may have a positive polarity, and the second external terminal <NUM> may have a negative polarity. In this case, the first external terminal <NUM> may be electrically connected to a first lead plate (not shown), and the second external terminal 202b may be electrically connected to a second lead plate (not shown). In this way, the first and second external terminals <NUM> and <NUM> may be electrically connected to the first and second lead plates (not shown) connected to the electrodes of one end and the other end of the plurality of battery cells <NUM>. The battery unit <NUM> is between the lower case <NUM> and the upper case <NUM> and accommodated in the lower case <NUM> and the upper case <NUM>. The battery unit <NUM> includes the plurality of battery cells <NUM> that may extend in a first direction (x-axis direction) and be aligned. Each of the plurality of battery cells <NUM> may include a first electrode terminal <NUM> and a second electrode terminal <NUM> and may include a vent hole <NUM> through which an internal gas may be discharged in a specific situation. A barrier <NUM> may be between the plurality of battery cells <NUM>. A spacer 320a may be provided at the barrier <NUM>, may be configured to separate the plurality of adjacent battery cells <NUM> and to form a space between the battery cells <NUM>, thereby providing a movement passage of a refrigerant for cooling each of the plurality of battery cells <NUM>.

Meanwhile, each of the battery cells <NUM> may connect between terminals of the other adjacent battery cell <NUM>. The plurality of battery cells <NUM> may be arranged in a line along the first direction (x-direction). Thus, the battery unit <NUM> may be arranged in a hexahedral shape. In the present embodiment, terminals of the plurality of battery cells <NUM> may be aligned in parallel with the x-z plane. The present disclosure is not limited thereto, and the terminals of the plurality of battery cells <NUM> may also be in parallel with other planes according to positions or a connecting method of the terminals.

The holder unit <NUM> may be between the battery unit <NUM> and the upper case <NUM>. The holder unit <NUM> will now be described in detail with reference to <FIG> and <FIG>.

<FIG> is a perspective view schematically illustrating the lower case <NUM> of the battery pack of <FIG>, and <FIG> is a perspective view schematically illustrating the case where the battery unit <NUM> is mounted on the lower case <NUM> of the battery pack of <FIG>.

Referring to <FIG>, the lower case <NUM> includes the bottom surface <NUM>, the first lower side wall <NUM> extending from the bottom surface <NUM>, the second lower side wall <NUM>, and the third lower side wall <NUM>. In the present embodiment, the bottom surface <NUM> of the lower case <NUM> has a rectangular shape.

In the present embodiment, the first lower side wall <NUM> may have a rectangular shape extending from a long side of the bottom surface <NUM>. The second lower side wall <NUM> and the third lower side wall <NUM> are arranged to face each other and may have the same shape. In the present embodiment, the second lower side wall <NUM> may extend from one short side of the bottom surface <NUM> and may be connected to one end of the first lower side wall <NUM>. Likewise, the third lower side wall <NUM> may extend from the other short side of the bottom surface <NUM> and may be connected to the other end of the first lower side wall <NUM>.

Each of the second lower side wall <NUM> and the third lower side wall <NUM> are connected to the first lower side wall <NUM> and are arranged to face each other. In the present embodiment, the bottom surface <NUM> has a rectangular shape and may include long sides and short sides. The first through third lower side walls <NUM> through <NUM> may have the same shape as the side wall and are connected to the bottom surface <NUM>. The first lower side wall <NUM> that is a main side wall may extend from long sides of the bottom surface <NUM>, and the second lower side wall <NUM> and the third lower side wall <NUM> that are sub-side walls may extend from short sides of the bottom surface <NUM>.

Meanwhile, as described above, the second lower side wall <NUM> and the third lower side wall <NUM> are provided to face each other. In the present embodiment, a side facing the first lower side wall <NUM> is open. Thus, the plurality of battery cells <NUM> may be easily embedded in the lower case <NUM>. A side of the lower case <NUM> of <FIG> facing the first lower side wall <NUM> is entirely open.

Meanwhile, inner walls <NUM> and <NUM> may be arranged at the second lower side wall <NUM> and the third lower side wall <NUM> of the lower case <NUM>, respectively. The inner wall <NUM> may be located inside the second lower side wall <NUM> and may be integrally formed with the second lower side wall <NUM>. Also, the inner wall <NUM> may be located inside the third lower side wall <NUM> and may be integrally formed with the third lower side wall <NUM>. The inner walls <NUM> and <NUM> may be arranged to face each other.

The inner walls <NUM> and <NUM> may have a first height <NUM> based on the first bottom surface <NUM>, and the second and third lower side walls <NUM> and <NUM> may have a second height <NUM> based on the first bottom surface <NUM>. In the present embodiment, the first height <NUM> of the inner walls <NUM> and <NUM> may be greater than the second height <NUM> of the second and third lower side walls <NUM> and <NUM>. Thus, the inner walls <NUM> and <NUM> may function to support the upper case <NUM> from the inside when the upper case <NUM> is coupled to the lower case <NUM>.

The inner walls <NUM> and <NUM> each may include protrusions 121a and 131a and insertion parts 121b and 131b. Referring to <FIG>, the protrusion 121a of the inner wall <NUM> may protrude in an +x-direction, and the protrusion 131a of the inner wall <NUM> may protrude in an -x-direction. Although not shown, in the upper case <NUM>, inner sides of the second upper side wall <NUM> and the third upper side wall <NUM> each corresponding to the second lower side wall <NUM> and the third lower side wall <NUM> of the lower case <NUM> may be formed to engage with the protrusions 121a and 131b and the insertion parts 121b and 131b of the inner walls <NUM> and <NUM> described above, so that the upper case <NUM> may be coupled to the lower case <NUM> as if it is fitted in the lower case <NUM>, and stronger support may be provided.

A plurality of first ribs <NUM> may be arranged on the bottom surface <NUM> inside the lower case <NUM>. As shown in <FIG>, each of the plurality of first ribs <NUM> may extend in a +y-direction. That is, each of the plurality of first ribs <NUM> may be in parallel with the short sides of the bottom surface <NUM>. In other words, each of the plurality of first ribs <NUM> may extend in a direction in parallel with the second lower side wall <NUM> or the third lower side wall <NUM>. The plurality of first ribs <NUM> may be arranged in a line along the first direction (x-axis direction).

Meanwhile, a plurality of second ribs <NUM> may be arranged between the plurality of first ribs <NUM>. Each of the plurality of second ribs <NUM> may be arranged at one side and the other side of the plurality of first ribs <NUM> and may be not arranged in the center of the plurality of first ribs <NUM>. Referring to <FIG>, the plurality of second ribs <NUM> may include a plurality of (<NUM>-<NUM>)-th ribs 162a located at one side of the plurality of first ribs <NUM> and a plurality of (<NUM>-<NUM>)-th ribs 162b located at the other side of the plurality of first ribs <NUM>. Each of the plurality of (<NUM>-<NUM>)-th ribs 162a and the plurality of (<NUM>-<NUM>)-th ribs 162b may form the second ribs <NUM> by pairing each other.

<FIG> illustrates a structure in which the battery unit <NUM> is mounted on the lower case <NUM>. Referring to <FIG> and <FIG>, the plurality of first ribs <NUM> and the plurality of second ribs <NUM> may be of a slot type on which each of the plurality of battery cells <NUM> may be seated. That is, as shown in <FIG>, each of the plurality of battery cells <NUM> may be seated on the bottom surface <NUM> of the lower case <NUM>.

Meanwhile, referring to <FIG>, the plurality of first ribs <NUM> may be formed with the first height <NUM>, and the plurality of second ribs <NUM> may be formed with the second height <NUM>. This will be described in detail with reference to <FIG>.

In the present embodiment, as shown in <FIG>, the height of the plurality of second ribs <NUM> may be greater than the height of the plurality of first ribs <NUM>. Each of the plurality of battery cells <NUM> may be located on the plurality of first ribs <NUM>, as shown in <FIG>. That is, the plurality of first ribs <NUM> may form a step from the bottom surface <NUM> of the lower case <NUM>, such that the plurality of battery cells <NUM> seated on the plurality of first ribs <NUM> may be apart from the bottom surface <NUM> of the lower case <NUM>. Because the plurality of second ribs <NUM> are arranged between the plurality of first ribs <NUM> and are formed with a greater height than the plurality of first ribs <NUM>, the plurality of second ribs <NUM> may be located between the plurality of battery cells <NUM>, may function to support the plurality of battery cells <NUM> and to maintain a distance between the battery cells <NUM>.

Meanwhile, as described above, one side of the lower case <NUM> may have an open shape. That is, an opposite side of the first lower side wall <NUM> of the lower case <NUM> may have an open shape. A terrace part <NUM> may be provided on the bottom surface <NUM> of the open side of the lower case <NUM>. A variety of members including a circuit board for electrical connection of the battery unit <NUM> may be located on the terrace part <NUM>.

Thus, the plurality of first ribs <NUM> may not extend to the terrace part <NUM>. That is, the plurality of first ribs <NUM> may extend from a side of the first lower side wall <NUM> up to the terrace part <NUM>. The length of the plurality of first ribs <NUM> may be changed according to the sizes of the battery cells <NUM>. However, in the present embodiment of <FIG>, the length of the plurality of first ribs <NUM> may be about <NUM>/<NUM> of the width of the bottom surface <NUM> in the y-axis direction. Thus, the terrace part <NUM> may be formed with about <NUM>/<NUM> of the width of the bottom surface <NUM> in the y-axis direction.

Meanwhile, as shown in <FIG>, the width of the inner walls <NUM> and <NUM> in the y-axis direction inside the second lower side wall <NUM> and the third lower side wall <NUM> may be the same as the length of the plurality of first ribs <NUM> in the y-axis direction. That is, the length of the plurality of first ribs <NUM> may be formed to correspond to the sizes of the plurality of battery cells <NUM>. Thus, the sizes of the inner walls <NUM> and <NUM> may also be formed to correspond to the sizes of the plurality of battery cells <NUM>. That is, as shown in <FIG>, the width of the inner walls <NUM> and <NUM> in the y-axis direction may be the same as the width of the plurality of battery cells <NUM>, and the height of the inner walls <NUM> and <NUM> in the z-axis direction may be the same as the height of the plurality of battery cells <NUM>. The inner walls <NUM> and <NUM> may protect the plurality of battery cells <NUM> arranged on the outermost side so as to protect the battery unit <NUM>.

<FIG> is a cross-sectional view schematically illustrating the case where the battery unit <NUM> is mounted on the lower case <NUM> of the battery pack of <FIG>, and <FIG> is a front view schematically illustrating the case where the battery unit <NUM> is mounted on the lower case <NUM> of the battery pack of <FIG>.

<FIG> and <FIG> illustrate the plurality of battery cells <NUM> mounted on the lower case <NUM>.

Referring to <FIG>, the battery cell <NUM> is mounted on the first rib <NUM>. The battery cell <NUM> may be seated on the first rib <NUM>. The first ribs <NUM> may be provided to have the first height <NUM> based on a top side 150a of the bottom surface <NUM> of the lower case <NUM>. The battery cells <NUM> may be seated on the first rib <NUM> and may be apart from the bottom surface <NUM> of the lower case <NUM> by the first height <NUM>.

The first rib <NUM> may include a jaw portion 161a located on one side of the first rib <NUM>. The jaw portion 161a may be connected to the first lower side wall <NUM> of the lower case <NUM>, and a lower end of one side of the battery cell <NUM> may be adjacent to the jaw portion 161a. Thus, the battery cells <NUM> may be apart from an inner side surface 110c of the first lower side wall <NUM> of the lower case <NUM> by a certain distance 161w corresponding to a degree of protrusion of the jaw portion 161a.

Meanwhile, the first rib <NUM> excluding the jaw portion 161a may be formed with a first length 161d. In the present embodiment, because the battery cells <NUM> may be arranged in such a way that the first electrode terminal <NUM> and the second electrode terminal <NUM> may face an open side of the lower case <NUM>, the length of the battery cells <NUM> in the y-axis direction may be greater than the first length 161d of the first ribs <NUM>. That is, one side of the battery cell <NUM> may be arranged to be in contact with the jaw portion 161a, and the other side at which the first electrode terminal <NUM> and the second electrode terminal <NUM> of the battery cell <NUM> are located, may protrude more than the first rib <NUM>. Thus, the other sides of the battery cells <NUM> may be apart from the bottom surface <NUM> by a certain distance corresponding to the first height <NUM>.

Meanwhile, the first ribs <NUM> may be located on the inner side surface of the bottom surface <NUM> of the lower case <NUM>, as described above. Referring to <FIG>, each of the plurality of battery cells <NUM> may be located between the plurality of first ribs <NUM> and the plurality of second ribs <NUM>. Each of the plurality of battery cells <NUM> may be seated on the plurality of first ribs <NUM> and may be supported by the plurality of second ribs <NUM> arranged at both sides of the plurality of first ribs <NUM>. The plurality of battery cells <NUM> may be of a slot type in which they are directly assembled on the bottom surface <NUM> of the lower case <NUM>. The plurality of battery cells <NUM> may be inserted between the plurality of second ribs <NUM> through forced fit, for example.

The plurality of second ribs <NUM> may be provided to have the second height <NUM>, and the plurality of first ribs <NUM> may be provided to have the first height <NUM>. In the present embodiment, the second height <NUM> of the plurality of second ribs <NUM> may be greater than the first height <NUM> of the plurality of first ribs <NUM>. The plurality of first ribs <NUM> are portions where the plurality of battery cells <NUM> are directly seated on the plurality of first ribs <NUM>, and each of the plurality of battery cells <NUM> mounted on the plurality of first ribs <NUM> may be apart from the bottom surface <NUM> of the lower case <NUM> by the first height <NUM>. Also, each of the plurality of second ribs <NUM> may be arranged between the plurality of first ribs <NUM>, such that the plurality of battery cells <NUM> may be inserted between the plurality of second ribs <NUM>.

Each of the plurality of battery cells <NUM> may be apart from each other by a certain distance 310w. The certain distance 310w between the plurality of battery cells <NUM> may be the same as a width 162w of the plurality of second ribs <NUM> in the x-direction. In this way, as the plurality of battery cells <NUM> are apart from each other by the certain distance 310w, swelling of the plurality of battery cells <NUM> may be prevented, and thermal propagation between the plurality of battery cells <NUM> may be prevented.

<FIG> is a side view schematically illustrating side walls of the battery pack of <FIG>, and <FIG> is an enlarged view of region A of <FIG>. The battery pack of <FIG> illustrates a shape in which the lower case <NUM> and the upper case <NUM> are coupled to each other.

Referring to <FIG>, the lower case <NUM> and the upper case <NUM> in the battery pack according to the present embodiment may be coupled to each other so as to be engaged with each other. Ends of the lower case <NUM> and the upper case <NUM> may be formed in a stepped shape (not a straight line shape), and the stepped shape of the upper case <NUM> may be formed so as to be engaged with the stepped shape of the lower case <NUM>.

In detail, ends of the second lower side wall <NUM> and the third lower side wall <NUM> of the lower case <NUM> may be formed in a stepped shape so as to be engaged with ends of the second upper side wall <NUM> and the third upper side wall <NUM> of the upper case <NUM>. <FIG> illustrates the second lower side wall <NUM> of the lower case <NUM> and the second upper side wall <NUM> of the upper case <NUM>. The third lower side wall <NUM> of the lower case <NUM> and the third upper side wall <NUM> of the upper case <NUM> are not separately illustrated but may have the same shape based on the shape of <FIG>.

The height of the second lower side wall <NUM> of the lower case <NUM> may decrease from one side 120a of the second lower side wall <NUM> to the other side 120b of the second lower side wall <NUM>. In this case, one side 120a of the second lower side wall <NUM> may be understood as a portion connected to the first lower side wall <NUM>. The height of the second lower side wall <NUM> may gradually decrease from one side 120a connected to the first lower side wall <NUM> to the other side 120b.

The second lower side wall <NUM> of the lower case <NUM> may include first through fourth areas A1 through A4 divided according to areas. In this case, the first through fourth areas A1 through A4 may be defined as areas by dividing the second lower side wall <NUM> according to heights.

The lower case <NUM> may be divided into the first area A1, the second area A2, the third area A3, and the fourth area A4 in order from one side 120a. That is, the first area A1 that is adjacent to the first lower side wall <NUM> may be formed to have a first height h1. The second area A2 that is adjacent to the first area A1 may be formed to have a second height h2. The third area A3 that is adjacent to the second area A2 may be formed to have a third height h3. The fourth area A4 that is adjacent to the third area A3 may be formed to have a fourth height h4.

In the present embodiment, the first area A1 and the third area A3 may be formed with a certain height. The first area A1 that extends from the first lower side wall <NUM>, as described above, may be formed with the same height as the first lower side wall <NUM>. The first height h1 of the first area A1 may be greater than the third height h3 of the third area A3. That is, as shown in <FIG>, the third height h3 of the third area A3 may be smaller than the first height h1 of the first area A1.

The second area A2 may have the second height h2 that gradually decrease from one side to the other side. An end of the second area A2 between the first area A1 and the third area A3 may be inclined. That is, the height of one side of the second area A2 may start at the same height as the first height h1 of the first area A1 but may gradually decrease toward the other side, and the other side of the second area A2 may be formed with the same height as the third height h3 of the third area A3.

The third area A3 may have a certain height, like in the first area A1, as described above, and the third height h3 of the third area A3 may be smaller than the first height h1 of the first area A1. The third area A3 may be in contact with the fourth area A4. The fourth area A4 may have a height gradually decreasing, like in the second area A2. That is, the fourth height h4 of the fourth area A4 may gradually decrease from one side to the other side of the fourth area A4 contacting the third area A3.

In an embodiment, the fourth height h4 of the fourth area A4 may decrease up to the bottom surface <NUM> at an end of the other side of the fourth area A4. It will be understood that this is because one side of the lower case <NUM> according to the present embodiment has an open shape, as described above. As described above, a top end of the second area A2 and the fourth area A4 on which the second area A2 and the fourth area A4 meet with the upper case <NUM>, may have certain angles Q2 and Q4 from the ground. These angles Q2 and Q4 may be provided as about <NUM>° to <NUM>°, for example, and preferably, the angles Q2 and Q4 of <NUM>°. The angles Q2 and Q4 of the top end of the second area A2 and the fourth area A4 of <FIG> are the same. However, the angles Q2 and Q4 of the top end of the second area A2 and the fourth area A4 may be different from each other.

Meanwhile, <FIG> illustrates one side surface of a configuration in which the lower case <NUM> and the upper case <NUM> are coupled to each other, in the battery pack of <FIG>. The second external terminal 202b may be located on one side of the upper case <NUM>.

Referring to <FIG> and <FIG>, the lower case <NUM> and the upper case <NUM> may be coupled to each other via the fastening member <NUM>. <FIG> illustrates the battery pack having the lower case <NUM> and the upper case <NUM> coupled thereto by the fastening member <NUM>, and <FIG> illustrates the battery pack having the lower case <NUM> and the upper case <NUM> separated therefrom by the fastening member <NUM>.

That is, the battery pack according to the present embodiment may be coupled by the fastening member <NUM> located at an end on which the lower case <NUM> and the upper case <NUM> are in contact with each other. In the present embodiment, the fastening member <NUM> may be of a hook type. However, the present disclosure is not limited thereto. The fastening member <NUM> may function to provide a coupling force to the lower case <NUM> and the upper case <NUM>, and the lower case <NUM> and the upper case <NUM> may be coupled to each other by other fastening structures according to the related art than the hook-type fastening member.

For example, the fastening member <NUM> may be formed of a combination of the first fastening member 190a and the second fastening member 190b. In the present embodiment, the first fastening member 190a may be located on the lower case <NUM>, and the second fastening member 190b may be located on the upper case <NUM>. The first fastening member 190a may have a protruding structure, and the second fastening member 190b may have a loop-shaped structure in which the first fastening member 190a may be inserted. The fastening member <NUM> may be inserted and coupled as the first protruding fastening member 190a is inserted into the second loop-shaped fastening member 190b.

In the present embodiment, a plurality of fastening members <NUM> may be provided, and at least one fastening member may be provided on a surface on which the lower case <NUM> and the upper case <NUM> are in contact with each other. <FIG> illustrates a side surface on which the second lower side wall <NUM> of the lower case <NUM> and the second upper side wall <NUM> of the upper case <NUM> meet with each other. Four fastening members <NUM> are provided on one side surface, however, the present disclosure is not limited thereto.

Meanwhile, referring to <FIG>, the first lower side wall <NUM> and the first upper side wall <NUM> in the state where the lower case <NUM> and the upper case <NUM> are coupled to each other, form one surface S1 of the battery pack that constitutes a rectangular parallelepiped. A sum HSI of the height of the first lower side wall <NUM> of the lower case <NUM> and the height of the first upper side wall <NUM> of the upper case <NUM> that constitute one surface S1 of the battery pack may be uniform. That is, the first lower side wall <NUM> and the first upper side wall <NUM> may be formed to be engaged with each other, as shown in <FIG>. Thus, the sum HSI of the height of the first lower side wall <NUM> and the height of the first upper side wall <NUM> may be the same.

<FIG> is a perspective view schematically illustrating the battery unit <NUM> to which the holder unit <NUM> is coupled, in the battery pack of <FIG>, and <FIG> is a perspective view schematically illustrating the holder unit <NUM> of the battery pack of <FIG>.

<FIG> illustrates the battery unit <NUM> and the holder unit <NUM> excluding the lower case <NUM> and the upper case <NUM> described above, and <FIG> illustrates only the holder unit <NUM>.

Referring to <FIG>, the battery unit <NUM> including a plurality of battery cells <NUM> is provided, and the battery unit <NUM> may have a hexahedral shape extending in an approximately x-axis direction. A plurality of bus bars <NUM> connecting the plurality of battery cells <NUM> may be provided on one surface of the battery unit <NUM>. Each of the plurality of bus bars <NUM> may be arranged to be in contact with terminals of the plurality of battery cells <NUM>. In the present embodiment, the terminals of the plurality of battery cells <NUM> may be located on the x-z plane, i.e., a surface perpendicular to the bottom surface <NUM>.

The holder unit <NUM> may be located on the battery unit <NUM> so as to cover at least two surfaces of the battery unit <NUM>. That is, the holder unit <NUM> may include a first holder member <NUM> and a second holder member <NUM>, which are bent at a preset angle, and each of the first holder member <NUM> and the second holder member <NUM> may be located on the battery unit <NUM>. In the present embodiment, the first holder member <NUM> may be located on the plurality of bus bars <NUM>, and the second holder member <NUM> may support the plurality of battery cells <NUM> from above. That is, as shown in <FIG>, the first holder member <NUM> may be located on the x-z plane, and the second holder member <NUM> may be located on the x-y plane. In the present embodiment, the holder unit <NUM> may further include the second holder member <NUM> extending perpendicular to the first holder member <NUM> in addition to the first holder member <NUM> covering the plurality of bus bars <NUM>, so that the holder unit <NUM> may function to entirely support the battery unit <NUM> without providing an additional fixing member.

The holder unit <NUM> may be bent at a preset angle, as described above. The holder unit <NUM> according to the present embodiment may be bent at an angle of approximately <NUM>°, i.e., the holder unit <NUM> may be formed in a '¬' shape.

The first holder member <NUM> of the holder unit <NUM> may be located on the plurality of bus bars <NUM>. The plurality of bus bars <NUM> may be coupled to the terminals of the plurality of battery cells <NUM>. Thus, the plurality of bus bars <NUM> may be arranged on both sides along the terminals of the plurality of battery cells <NUM>. A vent hole <NUM> may be provided in the center of the terminals of the plurality of battery cells <NUM>. Thus, based on the plurality of bus bars <NUM>, it will be understood that the vent hole <NUM> is located in the center of the plurality of bus bars <NUM>.

Meanwhile, referring to <FIG> together, an insulating gasket member <NUM> may be provided between the battery unit <NUM> and the first holder member <NUM> of the holder unit <NUM>. The insulating gasket member <NUM> may be formed of a heat-resistant material and may be a gasket that may prevent gas leakage. As the battery unit <NUM> according to the present embodiment is charged and discharged, heat is generated therein. In this case, the plurality of battery cells <NUM> may dissipate high heat to the surroundings, and the insulating gasket member <NUM> mounted on the battery unit <NUM> may be melted by the heat. In this way, when the insulating gasket member <NUM> is melted, a sealing ability between the insulating gasket member <NUM> and the holder unit <NUM> may be reduced so that gas may leak.

In an embodiment, when the battery unit <NUM> and the holder unit <NUM> are formed of different materials, the battery unit <NUM> and the holder unit <NUM> may be not easily in contact with each other, and gas may leak at a portion where the contact is weak. In order to prevent this, the insulating gasket member <NUM> that is a gasket may be provided between the battery unit <NUM> and the holder unit <NUM>, and airtightness between the battery unit <NUM> and the holder unit <NUM> may be easily maintained by the insulating gasket member <NUM>.

The insulating gasket member <NUM> may be provided as a single body, because a plurality of vent holes <NUM> of the plurality of battery cells <NUM> may be sealed at once. In this case, a plurality of openings <NUM> corresponding to the plurality of vent holes <NUM> may be provided on the insulating gasket member <NUM>. The size of each of the plurality of openings <NUM> may be equal to or greater than the size of each of the plurality of vent holes <NUM>. When the size of each of the plurality of openings <NUM> is greater than the size of each of the plurality of vent holes <NUM>, the insulating gasket member <NUM> is less likely to be melted because the insulating gasket member <NUM> does not come into direct contact with high-temperature gas discharged from the plurality of vent holes <NUM>.

The holder unit <NUM> may include a gas outlet <NUM> at one side thereof and may be in close contact with the insulating gasket member <NUM>, thereby forming a flow path of gas connected to the gas outlet <NUM>. As the plurality of battery cells <NUM> are charged and discharged, gas may be generated as a by-product of electrode plates and an electrolyte, and the gas may be discharged through the vent holes <NUM>. The gas may be discharged to the outside through the gas outlet <NUM> provided at the holder unit <NUM>. In this case, the gas outlet <NUM> may have a cylindrical shape, because it does not affect an adjacent battery pack. However, the shape of the gas outlet <NUM> is not limited thereto.

Meanwhile, the holder unit <NUM> may further include a projection member <NUM> including a plurality of projections in the second holder member <NUM> so as to press and fix the battery unit <NUM>. Referring to <FIG>, the projection member <NUM> may be located at a bottom surface of the second holder member <NUM> so as to press and support the battery unit <NUM> in a -z-direction from above, and a plurality of projections may be arranged to form a matrix. The projection member <NUM> may improve a fixing force of the battery unit <NUM> directly mounted on the lower case <NUM> without being separately modulated by pressing and supporting the battery unit <NUM> in the -z-direction from above.

The holder unit <NUM> may further include a ventilation member <NUM> including a plurality of ventilation holes in the second holder member <NUM> so as to discharge heat dissipated from the battery unit <NUM> to the outside. Referring to <FIG>, the ventilation member <NUM> may be formed to pass through the second holder member <NUM>, and a plurality of ventilation holes may be arranged to form a matrix. Referring to <FIG>, the ventilation member <NUM> may be formed between projection members <NUM>. The flow of air in the battery pack may be smoothly performed through the ventilation member <NUM> so that a cooling effect of the battery unit <NUM> may be enhanced.

<FIG> is a cross-sectional view schematically illustrating the lower case <NUM> and the upper case <NUM> of the battery pack of <FIG>, and <FIG> is a cross-sectional view schematically illustrating the battery pack of <FIG>.

As described above, when the battery pack is configured, proper temperature maintenance inside the battery pack is essentially required for the lifespan and stability of the plurality of battery cells <NUM>. In particular, in the case of an air cooling type battery pack, the key is whether the path of the air cooling type battery pack can cool the front sides of the plurality of battery cells <NUM>. Hereinafter, a battery pack according to the present embodiment that may easily solve the above-described problems is provided.

Referring to <FIG> and <FIG>, a first ventilation part 110a may be provided on the first lower side wall <NUM> of the lower case <NUM>, and a second ventilation part 110b may be provided on the fourth upper side wall <NUM> of the upper case <NUM>. The first ventilation part 110a may be formed through the first lower side wall <NUM> of the lower case <NUM>, and the second ventilation part 110b may be formed through the fourth upper side wall <NUM> of the upper case <NUM>.

In the present embodiment, the first ventilation part 110a may be located at a first height 110h1 based on the top surface 150a of the bottom surface <NUM>, the second ventilation part 110b may be located at a second height 110h2 based on the top surface 150a of the bottom surface <NUM>. In this case, the second height 110h2 at which the second ventilation part 110b is located, may be greater than the first height 110h1 at which the first ventilation part 110a is located.

In general, cold air is located at the bottom, and warm air is located at the top, causing convection. Thus, cold air is introduced into the battery pack through the first ventilation part 110a located in a relatively low position, and the cold air cools the battery unit <NUM> located inside the battery pack, and air passing through the battery unit <NUM> absorbs heat of the battery unit <NUM>, and the absorbed heat is discharged to the outside through the second ventilation part 110b located in a relatively high position. The positions of the first ventilation part 110a and the second ventilation part 110b use a convection phenomenon of air, so that convention of air within the battery pack may be easily performed and thus the battery pack may be efficiently cooled.

A cooling path CP that is the flow of air described above is illustrated as an arrow of <FIG>. As shown in <FIG>, air introduced into the battery pack through the first ventilation part 110a may cool the side surface of the battery unit <NUM>, may pass through the battery unit <NUM> and may pass through the ventilation member <NUM> of the holder unit <NUM> located on the battery unit <NUM>. The cooling path CP passing through the ventilation member <NUM> of the holder unit <NUM> may pass through a separated space d1 between the holder unit <NUM> and the upper case <NUM> and may move in a direction in which a fan <NUM> is provided. The cooling path CP moving to the side at which the fan <NUM> is located, may pass through the separated space d2 between a first circuit board <NUM> and a second circuit board <NUM>. For example, the first circuit board <NUM> may be a battery disconnect unit (BDU), and the second circuit board <NUM> may be a battery management system (BMS). The fan <NUM> may induce the cooling path CP toward the second ventilation part 110b due to a rotational force and may function to adjust the speed of the cooling path CP within the battery unit <NUM>.

<FIG> is a cross-sectional view schematically illustrating the lower case <NUM> and the upper case <NUM> on which the battery unit <NUM> is mounted, in the battery pack of <FIG>.

As described above, a battery pack according to the related art forms a module in which the plurality of battery cells <NUM> are stacked, and the module is mounted in the battery pack. In such a module structure, an external case in which the battery unit <NUM> is embedded, is not affected by internal components but has only the function of protecting the internal components and the function of packaging the battery pack. However, in such a battery pack, the size of the battery pack is increased due to the module structure inside the battery pack, and too many components compared to the number of the plurality of battery cells <NUM> are required, causing an increase in the weight, process and cost of the entire battery pack and thus there was a problem that this method is not proper for a method of constructing an optimum battery pack.

Thus, in the battery pack according to the present embodiment, the module structure inside the battery pack causing an increase in the weight, process and cost caused by the number of components when the battery pack is implemented, is not applied, but a structure for pressing the battery unit <NUM> toward the upper case <NUM> and increasing a constraint force is applied so that a structure in which the plurality of battery cells <NUM> may be directly seated inside the battery pack without using a module structure, may be provided.

Referring to <FIG>, the battery pack according to the present embodiment may include a support member <NUM> provided on the top surface <NUM> of the upper case <NUM> so as to press the battery unit <NUM> in the z-axis direction. The support member <NUM> may be located at a lower part of the top surface <NUM> of the upper case <NUM> and may be formed to protrude toward the battery unit <NUM>. In <FIG>, the support member <NUM> is located in two rows. However, the position and the number of support members <NUM> may be modified in various embodiments.

Referring to <FIG>, the holder unit <NUM> may be between the battery unit <NUM> and the support member <NUM>. That is, the second holder member <NUM> of the holder unit <NUM> extending along a lengthwise direction (y-axis direction) of the plurality of battery cells <NUM> may be arranged to surround at least part of one side surface of the battery unit <NUM>, and the support member <NUM> may be in direct contact with the holder unit <NUM> so as to entirely press the holder unit <NUM> and the battery unit <NUM>.

Meanwhile, a fixing member <NUM> may be located at a portion connecting the first upper side wall <NUM> to the top surface <NUM> of the upper case <NUM>. The fixing member <NUM> may be inserted into the battery unit <NUM> so as to press the battery unit <NUM> in the portion connecting the top surface <NUM> to the first upper side wall <NUM>.

The support member <NUM> may press the battery unit <NUM> in the -z-direction from above, and the fixing member <NUM> may press the battery unit <NUM> in the -y-direction from the side. In this way, the battery unit <NUM> pressed simultaneously in the first direction and the second direction may be more stably seated within the lower case <NUM> through the fixing member <NUM> and the support member <NUM>.

Claim 1:
A battery pack comprising:
a lower case (<NUM>) comprising a first lower side wall (<NUM>) extending from a bottom surface (<NUM>), and a second lower side wall (<NUM>) and a third lower side wall (<NUM>) respectively connected with the first lower side wall (<NUM>) and arranged so as to face each other, wherein the side facing the first lower side wall (<NUM>) is entirely open;
a battery unit (<NUM>) accommodated in the lower case (<NUM>) and comprising a plurality of battery cells (<NUM>); and
an upper case (<NUM>) arranged to face the lower case (<NUM>) so as to seal the battery unit (<NUM>),
wherein the upper case (<NUM>) comprises a first upper side wall (<NUM>) extending from a top surface (<NUM>), a second upper side wall (<NUM>) and a third upper side wall (<NUM>) respectively connected with the first upper side wall (<NUM>) and arranged to face each other, a fourth upper side wall (<NUM>) arranged to face the first upper side wall (<NUM>), and the first upper side wall (<NUM>) and the lower side wall, the second upper side wall (<NUM>) and the second lower side wall (<NUM>), and the third upper side wall (<NUM>) and the third lower side wall (<NUM>) are arranged to be engaged with one another, and at least part of the fourth upper side wall (<NUM>) is arranged to face the first lower side wall (<NUM>),
wherein a sum of a height of the first lower side wall (<NUM>) of the lower case (<NUM>) and a height of the first upper side wall (<NUM>) of the upper case (<NUM>) is the same as a height of the fourth upper side wall (<NUM>) of the upper case (<NUM>),
wherein the upper and lower cases are rectangular.