Patent Description:
In general, electric vehicles are vehicles that obtain power by driving an AC or DC motor using power supplied from a battery. Electric vehicles may be largely classified into battery-exclusive electric vehicles and hybrid electric vehicles.

Battery-exclusive electric vehicles drive a motor using power from a battery and recharge the battery when the power is exhausted. In the case of the battery-exclusive electric vehicle, a plurality of battery packs may be mounted on a lower portion thereof. The electric vehicle has a high risk of battery damage due to an impact to the lower portion of the vehicle caused by various events while driving, such as striking debris or obstacles in the roadway. Therefore, it is desirable to have a system and method capable of preventing the damage of the battery due to the impact to the lower portion of the electric vehicle.

The above-described information disclosed in the technology that serves as the background of the present disclosure is only for improving understanding of the background of the present disclosure and thus may include information that does not constitute the related art.

<CIT> discloses a battery housing for a vehicle battery with at least one module holder for holding a battery module, which is delimited at least by a side wall and an intermediate floor, and with an underride guard arranged below the intermediate floor for protection against undesired penetration of objects from below, wherein the underride guard is reinforced in such a way that a force acting on the underride guard from below can be introduced into the side wall and deformation of the intermediate floor is essentially avoided.

<CIT> discloses a battery pack protection system for use with an electric vehicle in which the battery pack is mounted under the car. The system utilizes a plurality of deformable cooling conduits located between the lower surface of each of the batteries and the lower battery pack enclosure panel, with a thermal insulator interposed between the conduits and the lower enclosure panel. The cooling conduits are configured to deform and absorb impact energy when an object, such as road debris, strikes the lower surface of the lower battery pack enclosure panel. Further protection may be achieved by positioning a ballistic shield, alone or with a layer of compressible material, under the bottom surface of the battery pack.

According to the invention a battery pack according to independent claim <NUM> is provided.

The lower panel may have a plate shape. The buffer parts may be provided on a surface of the lower panel facing the battery module.

Some or all of the buffer parts may extend in a longitudinal direction of the lower panel and/or may each have a hollow pipe shape.

The number of concave portions may be the same as the number of concave portions for the left side surface and/or for the right side surface. The left side surface may have the same type of shape as the right side surface. In some embodiments, there may be two or more types of buffer parts having different structures.

The battery pack may also include a number of cooling passages in a lower portion of the battery module, and the cooling passages may be between adjacent buffer parts.

Each of the cooling passages may be sized such that they are not in contact with the lower panel.

Hereinafter, a lower protective cover and a battery pack having the same according to embodiments will be described in detail with reference to the accompanying drawings.

<FIG> illustrates a perspective view of a lower portion of a battery pack according to embodiments. <FIG> illustrates an exploded perspective view of the battery pack of <FIG>.

Referring to <FIG> and <FIG>, a battery pack <NUM> according to embodiments may include a lower protective cover <NUM> seated on an installation surface of a vehicle, etc., and a battery module <NUM> that accommodates and covers a plurality of battery cells <NUM> (see <FIG>). The lower protective cover <NUM> may be detachably coupled to a lower portion of the battery module <NUM>. Thus, when the lower protective cover <NUM> is damaged, only the lower protective cover <NUM> may be separated to be replaced.

The lower protective cover <NUM> may include a lower panel <NUM> having a substantially rectangular plate shape and a plurality of buffer parts <NUM> provided on the lower panel <NUM> (e.g., on an upper surface of the lower panel <NUM>).

The shape of the lower panel <NUM> may correspond to a lower shape of the battery module <NUM>. Since the lower panel <NUM> supports the battery module <NUM> from a lower side, the lower panel <NUM> may have a size capable of completely covering (or substantially completely covering) the lower portion of the battery module <NUM>. Since the lower panel <NUM> has to be able to prevent the battery module <NUM> from being damaged, the lower panel <NUM> may be made of various materials such as steel, aluminum, and a material mixed with various materials (e.g., an alloy). In some embodiments, when the lower panel <NUM> is made of aluminum, the lower panel <NUM> may be manufactured through a stamping method. Referring to <FIG>, the plurality of buffer parts <NUM> may be coupled to a top surface of the lower panel <NUM> and extend in a longitudinal direction along the length of the lower panel <NUM>. There may be, for example, between <NUM> and <NUM> buffer parts <NUM> or between <NUM> and <NUM> buffer parts <NUM> arranged on the lower panel. In the embodiment depicted in <FIG>, there is a total number of <NUM> buffer parts <NUM> arranged on the lower panel. The buffer parts <NUM> may be arranged in two groups, each consisting of half of the total number of buffer parts <NUM>.

<FIG> illustrates a cross-sectional view taken along line A-A' of <FIG>. <FIG> illustrates an enlarged cross-sectional view of the buffer part of the lower protective cover of <FIG>.

Referring to <FIG>, the plurality of buffer parts <NUM> may be disposed in the longitudinal direction on the top surface of the lower panel <NUM>. The buffer part <NUM> may be manufactured through an extrusion method and may be made of the same material as the lower panel <NUM>. In some embodiments, the buffer parts <NUM> may be coupled to the lower panel <NUM> by welding. In the illustrated embodiment, each of the buffer parts <NUM> has a length less than that of the lower panel <NUM>. Each buffer part <NUM> may have a hollow pipe shape or a hollow prismatic shape. In some embodiments, the buffer parts <NUM> may have various cross-sectional shapes, but may have a cross-sectional shape capable of absorbing an impact. When the buffer parts <NUM> are seated on the lower panel <NUM> (in some embodiments, the buffer part is provided to have a separate bottom surface, but since the bottom surface is welded and connected to the lower panel <NUM>, reference numerals of the bottom surface are omitted for convenience), the buffer parts <NUM> may include a top surface <NUM> spaced apart from the bottom surface. The top surface <NUM> may be facing and parallel to the bottom surface and left and right surfaces <NUM> connecting the bottom surface to opposite sides or ends of the top surface <NUM>. The buffer part <NUM> may have a hollow interior 120a having various shapes depending on the shapes of the bottom surface, the top surface <NUM>, and the left and right surfaces <NUM>. Each of the left and right surfaces <NUM> may be concave inward from an end of the top surface <NUM> or the bottom surface (e.g., the left and right surfaces <NUM> may extend concavely inward into the hollow interior 120a). In some embodiments, each of the left and right surfaces <NUM> may have a shape of which an approximately center in a vertical direction in <FIG> is concave. In some embodiments, the hollow interior 120a may have a substantially hourglass-like shape. The shape of the buffer parts <NUM> having the hollow interiors 120a may have a structure for absorbing an impact applied from the lower side of the lower protective cover <NUM>. That is, the left and right surfaces <NUM> may absorb the impact while being compressed or deformed in the vertical direction (direction B in <FIG>) by an impact in a downward direction. In some embodiments, the impact applied to the battery cell <NUM> may be absorbed by the deformation of the buffer parts <NUM>.

A degree of inward concaveness of each of the left and right surfaces <NUM> may be indicated by a central angle (theta (θ)) in <FIG>. The angle theta (θ) is formed by two adjacent sections of the left or right surface <NUM>, respectively. In some embodiments, a thickness of each of the left and right surfaces <NUM> may be indicated by reference symbol T in <FIG>. In other words, the left side wall and the right side wall of the buffer part <NUM> each may have a thickness T. In some embodiments, an angle θ of each of the left and right sides <NUM> of the buffer part <NUM> may be in the range of about <NUM> degrees to about <NUM> degrees or in the range of about <NUM> degrees to <NUM> degrees. In some embodiments, the thickness of each of the left and right surfaces <NUM> may be in the range of about <NUM> to about <NUM>, in the range of about <NUM> to <NUM>, or in the range of about <NUM> to <NUM>. An impact absorption amount may be adjusted by adjusting the angle and thickness of the side surface <NUM>. Exemplary impact absorption amounts for each thickness and angle of the side surface <NUM> are shown in the table below.

Referring to <FIG> and <FIG>, the battery module <NUM> may have a substantially rectangular parallelepiped shape, and the plurality of battery cells <NUM> may be mounted in the battery module <NUM>. Referring to <FIG>, a plurality of cooling passages <NUM> may be provided in the bottom surface of the battery module <NUM> in the longitudinal direction. The cooling passage <NUM> may be disposed so as not to overlap the buffer part <NUM> described above (e.g., one, two or more cooling passages <NUM> may be between adjacent buffer parts <NUM>). In some embodiments, a protruding width of each of the cooling passages <NUM> (width in the vertical direction in <FIG>) may be less than that of the buffer part <NUM> (width in the vertical direction in <FIG>). The width may be an extension in the direction from the top surface to the bottom surface of the buffer part <NUM>. That is, in one or more embodiments the cooling passages <NUM> may be shorter than the buffer parts <NUM> in the vertical direction B (shown in <FIG>). In some embodiments, an empty space may be generated between the cooling passage <NUM> and the buffer <NUM> (e.g., gaps may be provided between the cooling passages <NUM> and the buffer parts <NUM> and/or between the cooling passages <NUM> and the lower panel <NUM>). The empty space may serve to buffer an impact generated from the lower side of the lower protective cover <NUM>. In some embodiments, the above-described empty space may be defined as an impact absorbing space 100a. The impact absorbing space 100a may be an entire empty space inside the lower protective cover <NUM> except for the buffer <NUM> and the cooling passage <NUM>. The above-described arrangement and shape of the cooling passage <NUM> and the buffer part <NUM> and the structure of the impact absorbing space 100a may be configured to prevent the cooling passage <NUM> and the battery cell <NUM> from being damaged even though the buffer part <NUM> is deformed by the impact applied from the lower side of the lower protective cover <NUM>.

The buffer part <NUM> described above may be implemented in various forms.

<FIG> illustrate enlarged cross-sectional views of a buffer part of a lower protective cover according to other embodiments of the present disclosure.

Referring to <FIG>, a buffer part <NUM>' may include a bottom surface (not separately marked with reference number) parallel to a lower panel <NUM>', a top surface <NUM>' spaced apart from and facing and parallel to the bottom surface, and left and right surfaces <NUM>' connecting the bottom surface to opposite sides or ends of the top surface <NUM>'. In some embodiments, each of the left and right surfaces <NUM>' may have a shape of which an approximately central portion in a vertical direction protrudes outward (e.g., the left and right surfaces <NUM>' may extend convexly outward away from the hollow interior 120a'). In some embodiments, the hollow interior 120a' defined by the top and bottom surfaces <NUM>' and the left and right surfaces <NUM>' may have a substantially hexagonal shape. When an impact occurs from a lower side, the buffer part <NUM>' may also be deformed in the vertical direction in <FIG> to absorb the impact.

In some embodiments, referring to <FIG>, a buffer part <NUM>" may include a bottom surface (not separately marked with reference number) parallel to a lower panel <NUM>", a top surface <NUM>" spaced apart from and facing and parallel to the bottom surface, and left and right surfaces <NUM>" connecting the bottom surface to opposite sides or ends of the top surface <NUM>". In some embodiments, each of the left and right surfaces <NUM>" may have a shape having both an inward concave portion and an outward protruding (convex) portion. Such a shape may be referred to as a concave-convex or wrinkled shape, a zigzag shape, or the like. In some embodiments, each of the concave portion and the convex portion may be repeated (provided in plurality). Each of the concave portion and the convex portion may be, for example, repeated two or three times. In some embodiments, a hollow interior 120a" defined by the top and bottom surfaces <NUM>" and the left and right surfaces <NUM>" may be provided in an irregular (atypical) shape.

By varying the angle theta, the thickness of the side walls and the shape of the buffer parts, e.g. the cross section of the buffer parts, the deformation characteristics of the buffer parts can be designed to achieve efficient protection of the battery module. The parameters mentioned can be adapted with respect to potential forces to be absorbed so that an advantageous ratio between weight, cost and protective effect can be achieved.

In the battery pack according to some embodiments having the above-described configuration, an event in which an impact occurs from a lower side will be described (for convenience, reference numbers in <FIG> are indicated based on the embodiment of <FIG>).

<FIG> illustrates a cross-sectional view of the battery pack and a lower impact generation direction in <FIG>. <FIG> and <FIG> illustrate a view of a state of battery pack when the lower impact occurs in the battery pack of <FIG>.

Since the battery pack <NUM> is mainly mounted on the lower portion of the electric vehicle, the impact may often be transmitted from the lower portion of the battery pack <NUM> according to conditions of a road surface (e.g., debris or obstacles on the road) referring to <FIG>. In some embodiments, an impact transmission portion may be a position of the buffer part <NUM> referring to <FIG> or may be a cooling passage <NUM> between the buffer parts <NUM> referring to <FIG>.

Referring to <FIG>, when the impact is transmitted to the position of the buffer part <NUM>, the buffer part <NUM> may be deformed to absorb the impact, thereby minimizing the transmission of the impact to the cooling passage <NUM> or the battery cell <NUM> or preventing the impact from being transmitted to the cooling passage <NUM> or the battery cell <NUM>.

Referring to <FIG>, when the impact is transmitted to the position of the cooling passage <NUM> between the buffer parts <NUM>, the impact absorbing space 100a may serve as the buffer part <NUM>. In some embodiments, since there are buffer parts <NUM> at both sides of the impact absorbing space 100a to absorb some impacts, the transmission of impacts to the cooling passage <NUM> or the battery cell <NUM> can be minimized or prevented.

According to some embodiments, the structure of the lower protective cover of the battery pack may be improved to absorb the impact from the lower side of the vehicle.

In addition, the cross-sectional shape of the buffer part of the lower protective cover may be changed to adjust and design the impact absorption value.

The battery pack may further comprise a plurality of cooling passages in a lower portion of the battery module, and the cooling passages may be arranged between adjacent buffer parts of the plurality of buffer parts.

Each cooling passage of the plurality of cooling passages in the battery pack may have a size such that is not in contact with the lower panel.

Claim 1:
A battery pack (<NUM>) comprising:
a battery module (<NUM>) accommodating a plurality of battery cells (<NUM>); and
a lower protective cover (<NUM>) comprising a lower panel (<NUM>, <NUM>') detachably coupled to a lower portion of the battery module (<NUM>) and a plurality of buffer parts (<NUM>) on one surface of the lower panel (<NUM>, <NUM>'), characterized in that
each buffer part (<NUM>) of the plurality of buffer parts (<NUM>) comprises a top surface and a bottom surface each being parallel to the lower panel (<NUM>, <NUM>'), and left and right side surfaces (<NUM>) connecting the top surface to the bottom surface, and wherein
each of the left and right side surfaces (<NUM>) has an inward concave shape and/or an outward convex shape.