Patent Description:
The present invention relates to a battery pack having a refrigerant circulation channel provided in a pack case, and more particularly to a battery pack having a refrigerant circulation channel provided in a pack case, wherein the refrigerant circulation channel, which is configured to discharge heat generated from a battery module, is provided in a frame, whereby it is possible to prevent leakage of a refrigerant and to reduce the volume of the battery pack while maintaining existing cooling performance.

With recent development of alternative energies due to air pollution and energy depletion caused as the result of use of fossil fuels, demand for secondary batteries capable of storing electrical energy that is produced has increased. The secondary batteries, which are being capable of being charged and discharged, are intimately used in daily life. For example, the secondary batteries are used in mobile devices, electric vehicles, and hybrid electric vehicles.

Required capacities of secondary batteries used as energy sources of various kinds of electronic devices inevitably used in modern society have been increased due to an increase in usage of mobile devices, increasing complexity of the mobile devices, and development of electric vehicles. In order to satisfy demand of users, a plurality of battery cells is disposed in a small-sized device, whereas a battery module including a plurality of battery cells electrically connected to each other or a battery pack including a plurality of battery modules is used in a vehicle.

In the battery module or the battery pack, a plurality of battery cells is connected to each other in series or in parallel in order to increase capacity and output of the battery module or the battery pack. In the case in which a plurality of battery cells is used in a state of being connected to each other, a problem, such as overload, may occur. In particular, for the battery pack, a battery module including a plurality of battery cells is located in a case. As a result, there is a problem in that temperature in the battery pack increases due to overload, whereby abnormality of the battery is amplified. In order to solve this problem, it is necessary for a general battery pack to have a cooling unit capable of lowering the temperature of the battery, whereby safety of the battery is improved, space efficiency of the battery is improved, and energy density of the battery is improved.

<FIG> is a sectional view of a conventional battery module. As shown in <FIG>, the conventional battery module includes a module case <NUM> configured to receive battery cells <NUM> therein, a heat sink <NUM> located at the lower surface of the battery module, and a protection member <NUM> configured to wrap the lower surface of the battery module. In the disclosed battery module, the heat sink <NUM>, which is in contact with the lower surface of the battery module, is provided with an opening formed by cutting a predetermined area thereof, whereby it is possible to improve efficiency of cooling the battery module and to prevent a refrigerant in the heat sink from leaking out of a contact interface thereof through the protection module <NUM>.

In the conventional art, as described above, a heat exchange process between the battery module and the refrigerant in the heat sink <NUM> is improved, whereby cooling performance is improved. Since a refrigerant supply line (not shown) configured to supply and collect the refrigerant to and from the heat sink <NUM> is exposed, however, there is a problem in that the volume of the battery pack is large.

In addition, since the refrigerant supply line (not shown), in which the refrigerant flows, is exposed, the refrigerant may leak due to damage to the refrigerant supply line when external impact is applied thereto, which may lead to a serious accident.

(Patent Document <NUM>) <CIT>
Document <CIT> discloses an apparatus for supporting a battery in a vehicle. Document <CIT> discloses a power supply device which has a cooling device that is as simple and compact as possible and can be easily connected to a cooling or refrigerant circuit. Document <CIT> discloses an electric vehicle power battery lower case.

The present invention has been made in view of the above problems, and it is an object of the present invention to provide a battery pack configured such that leakage of a refrigerant from the battery pack is minimized.

It is another object of the present invention to provide a battery pack configured such that an increase in volume of the battery pack due to various parts configured to perform cooling is inhibited.

It is a further object of the present invention to provide a battery pack configured such that leakage of a refrigerant is restricted even in the case in which a frame is damaged due to external impact.

In order to accomplish the above objects, a battery pack according to the present invention includes at least one battery module (<NUM>); a pack case (<NUM>) configured to receive the battery module (<NUM>) therein; and a cooling unit (<NUM>) located between an inside upper surface of the pack case (<NUM>) and the battery module (<NUM>), the cooling unit being configured to discharge heat generated from the battery module (<NUM>).

The pack case (<NUM>) is provided with a refrigerant circulation channel (<NUM>) therein configured to supply and collect a refrigerant to and from the cooling unit (<NUM>).

Also, in the battery pack according to the present invention, the pack case (<NUM>) includes a front frame (<NUM>), a rear frame (<NUM>), and a pair of side frames (<NUM>) connecting the front frame (<NUM>) and the rear frame (<NUM>) to each other.

The refrigerant circulation channel (<NUM>) is provided in each of the pair of side frames (<NUM>).

Also, in the battery pack according to the present invention, the front frame (<NUM>) may have a pair of a refrigerant introduction port (<NUM>) and a refrigerant discharge port (<NUM>) spaced apart from each other by a predetermined distance, and a refrigerant transfer pipe (<NUM>) in communication with the refrigerant circulation channel (<NUM>) may be connected to each of the refrigerant introduction port (<NUM>) and the refrigerant discharge port (<NUM>).

Also, in the battery pack according to the present invention, an air circulation channel (<NUM>) is located adjacent to the refrigerant circulation channel (<NUM>) of the side frame (<NUM>) so as to be parallel to the refrigerant circulation channel (<NUM>).

Also, in the battery pack according to the present invention, the air circulation channel (<NUM>) has at least one incision portion (<NUM>) configured to allow external air to pass therethrough.

Also, in the battery pack according to the present invention, the cooling unit (<NUM>) may include a heat sink (<NUM>), a first heat dissipation plate (<NUM>) located between the heat sink (<NUM>) and the pack case (<NUM>), and a second heat dissipation plate (<NUM>) located between the heat sink (<NUM>) and the bottom surface of the pack case (<NUM>).

Also, in the battery pack according to the present invention, the heat sink (<NUM>) may include a pair of a lower plate (<NUM>') and an upper plate (<NUM>") configured to provide a space in which a refrigerant is circulated and a refrigerant inlet (<NUM>) and a refrigerant outlet (<NUM>) detachably coupled to the refrigerant circulation channel (<NUM>).

Also, in the battery pack according to the present invention, the bottom surface of the side frame (<NUM>) may have fastening holes (<NUM>) connected to the refrigerant inlet (<NUM>) and the refrigerant outlet (<NUM>).

Also, in the battery pack according to the present invention, the refrigerant circulation channel (<NUM>) of the pack case (<NUM>) may have a refrigerant circulation pipe (<NUM>) received therein and configured to supply and collect the refrigerant to and from the cooling unit (<NUM>).

In addition, the present invention may provide a device having mounted therein the battery pack having one or more of the features mentioned above.

As is apparent from the above description, a battery pack having a refrigerant circulation channel provided in a pack case according to the present invention has a merit in that the refrigerant circulation channel (<NUM>) is provided in a side frame (<NUM>), whereby it is possible to minimize leakage of a refrigerant even in the case in which external impact is applied thereto.

Also, in the battery pack having the refrigerant circulation channel provided in the pack case according to the present invention, it is possible to reduce the overall volume of the battery pack, which may contribute to improvement in energy density thereof, since the refrigerant circulation channel (<NUM>) is provided in the side frame (<NUM>).

Furthermore, the battery pack having the refrigerant circulation channel provided in the pack case according to the present invention has an advantage in that an air circulation channel (<NUM>) is further provided in the side frame (<NUM>) along the refrigerant circulation channel (<NUM>), whereby it is possible to improve cooling efficiency and to reduce the overall weight of the battery pack.

In the case in which one part is said to be connected to another part in the entire specification, not only may the one part be directly connected to the other part, but also, the one part may be indirectly connected to the other part via a further part.

<FIG> is a perspective view of a battery pack according to a preferred embodiment of the present invention, and <FIG> is an exploded perspective view of the battery pack according to the preferred embodiment of the present invention.

Referring to <FIG> and <FIG>, the battery pack according to the present invention includes a battery module <NUM>, a pack case <NUM> configured to receive the battery module <NUM> therein, and a cooling unit <NUM> configured to remove heat generated from the battery module <NUM>.

When describing the battery module <NUM> first, the battery module may include at least one unit cell. Here, the unit cell may include an electrode assembly and a cell case configured to receive the electrode assembly therein. The electrode assembly may be a jelly-roll type electrode assembly, which is configured to have a structure in which a long sheet type positive electrode and a long sheet type negative electrode are wound in the state in which a separator is interposed therebetween, a stacked type electrode assembly including unit cells, each of which is configured to have a structure in which a rectangular positive electrode and a rectangular negative electrode are stacked in the state in which a separator is interposed therebetween, a stacked and folded type electrode assembly, which is configured to have a structure in which unit cells are wound using a long separation film, or a laminated and stacked type electrode assembly, which is configured to have a structure in which unit cells are stacked in the state in which a separator is interposed therebetween and are then attached to each other. However, the present invention is not limited thereto. It is preferable for the electrode assembly according to the present invention to be a stacked and folded type electrode assembly or a laminated and stacked type electrode assembly, which has lowest physical stress when a curved module is formed.

The electrode assembly is received in the cell case. The cell case is generally configured to have a laminate sheet structure including an inner layer, a metal layer, and an outer layer. The inner layer is disposed in direct contact with the electrode assembly, and therefore the inner layer must exhibit high insulation properties and high resistance to an electrolytic solution. In addition, the inner layer must exhibit high sealability in order to hermetically seal the cell case from the outside, i.e. a thermally-bonded sealed portion between inner layers must exhibit excellent thermal bonding strength. The inner layer may be made of a material selected from among a polyolefin-based resin, such as polypropylene, polyethylene, polyethylene acrylate, or polybutylene, a polyurethane resin, and a polyimide resin, which exhibit excellent chemical resistance and high sealability. However, the present invention is not limited thereto, and polypropylene, which exhibits excellent mechanical-physical properties, such as tensile strength, rigidity, surface hardness, and resistance to impact strength, and excellent chemical resistance, is the most preferably used.

The metal layer, which is disposed so as to abut the inner layer, corresponds to a barrier layer configured to prevent moisture or various kinds of gas from permeating into the battery from the outside. An aluminum thin film, which is light and easily shapeable, may be used as a preferred material for the metal layer.

The outer layer is provided on the other surface of the metal layer. The outer layer may be made of a heat-resistant polymer that exhibits excellent tensile strength, resistance to moisture permeation, and resistance to air transmission such that the outer layer exhibits high heat resistance and chemical resistance while protecting the electrode assembly. As an example, the outer layer may be made of nylon or polyethylene terephthalate. However, the present invention is not limited thereto.

Although a total of nine battery modules <NUM> is shown as being received in the figures, which is merely an illustration, the number of battery modules may be changed.

The pack case <NUM>, which is configured to receive the battery modules <NUM> therein and to protect the battery modules <NUM> from external impact, includes a front frame <NUM>, a rear frame <NUM>, and a pair of side frames <NUM>.

Specifically, a pair of a refrigerant introduction port <NUM> and a refrigerant discharge port <NUM> is fixed to the front frame <NUM> in a state of being spaced apart from each other by a predetermined distance, and a pair of refrigerant transfer pipes <NUM> is connected to these ports so as to extend toward the side frames <NUM>.

Consequently, a refrigerant, cooled to a predetermined temperature, from the outside is injected into the refrigerant introduction port <NUM> and then flows along the refrigerant transfer pipe <NUM> connected to the refrigerant introduction port <NUM>. The refrigerant, heated to a predetermined temperature as a result of absorbing heat of the battery modules <NUM>, is discharged through the other refrigerant transfer pipe <NUM> and the refrigerant discharge port <NUM>. After being cooled to a predetermined temperature, the refrigerant is resupplied.

Here, the pair of the refrigerant transfer pipes <NUM> supplies and collects the refrigerant to and from the side frames <NUM>. A detailed description related thereto will be given below.

Meanwhile, a plurality of partition walls may be provided on the bottom surface of the pack case <NUM> such that the battery modules <NUM> are spaced apart from each other by a predetermined distance.

The cooling unit <NUM>, which is configured to remove heat generated from the battery modules <NUM>, is located between the battery modules <NUM> and an inside upper surface of the pack case <NUM>, and includes a heat sink <NUM> and a first heat dissipation plate <NUM> between the heat sink <NUM> and the pack case <NUM>. A detailed description related thereto will be given below.

<FIG> is a sectional view taken along line A-A' of <FIG>, <FIG> is a perspective view showing a side frame according to a preferred embodiment of the present invention, and <FIG> is a perspective view illustrating coupling of the side frame according to the preferred embodiment of the present invention.

Referring to <FIG>, the pair of side frames <NUM> according to the present invention is spaced apart from each other by a predetermined distance in order to connect the front frame <NUM> and the rear frame <NUM> to each other, and each side frame <NUM> is provided with a refrigerant circulation channel <NUM> connected to a corresponding one of the refrigerant transfer pipes <NUM>, an air circulation channel <NUM>, an incision portion <NUM>, and a fastening hole <NUM>.

First, the refrigerant circulation channel <NUM> connected to one side of the refrigerant transfer pipe <NUM> is configured to have a shape extending through the side frame <NUM> in a longitudinal direction thereof. Consequently, a cool refrigerant to be supplied to the heat sink <NUM> flows in the refrigerant circulation channel <NUM> connected to the refrigerant transfer pipe <NUM> communicating with the refrigerant introduction port <NUM>, and a refrigerant heated to a predetermined temperature as a result of heat absorption moves in the refrigerant circulation channel <NUM> connected to the refrigerant transfer pipe <NUM> communicating with the refrigerant discharge port <NUM>.

Conventionally, the refrigerant circulation channel is separately manufactured and is then connected to the side surface or the bottom surface of the pack case, and therefore the refrigerant circulation channel may be easily damaged due to external impact. Furthermore, there is a problem in that a refrigerant that leaks from the refrigerant circulation channel as a result of damage to the refrigerant circulation channel may cause a new event.

In contrast, the refrigerant circulation channel <NUM> according to the present invention is provided in the side frame <NUM>, and therefore there are advantages in that a danger of damage to the refrigerant circulation channel due to external impact may be minimized and the overall volume of the battery pack may be reduced.

The air circulation channel <NUM> is located in the state in which a separation wall is disposed between the air circulation channel and the refrigerant circulation channel <NUM> such that no refrigerant leaks into the air circulation channel. At this time, the air circulation channel extends long parallel to the refrigerant circulation channel <NUM> such that the refrigerant moving in the refrigerant circulation channel <NUM> is cooled as naturally as possible.

Furthermore, the air circulation channel <NUM> is provided with at least one incision portion <NUM>, through which external air may pass, whereby more efficient cooling is possible. That is, since the air circulation channel <NUM> is further provided in the side frame <NUM> along the refrigerant circulation channel <NUM>, it is possible to rapidly cool the battery pack and to reduce the overall weight of the battery pack.

Meanwhile, each of the pair of side frames <NUM> is provided in the bottom surface thereof with at least one fastening hole <NUM> configured to communicate with the refrigerant circulation channel <NUM>, more specifically fastening holes <NUM> equal in number to refrigerant inlets <NUM> or refrigerant outlets <NUM> of the heat sink <NUM> located under the battery modules <NUM>.

For example, for the side frame <NUM> sequentially connected to the refrigerant introduction port <NUM> and the refrigerant transfer pipe <NUM>, the fastening holes <NUM> formed in the bottom surface of the side frame <NUM> are respectively fixed to the refrigerant inlets <NUM> of the heat sink <NUM> by fastening. Consequently, a refrigerant introduced into the refrigerant introduction port <NUM> sequentially moves along the refrigerant transfer pipe <NUM> and the refrigerant circulation channel <NUM> and is then supplied to the refrigerant inlets <NUM> of the heat sink <NUM>.

In the same manner, the other side frame <NUM> connected to the refrigerant discharge port <NUM> and the refrigerant transfer pipe <NUM> has the same coupling structure as described above, and a heated refrigerant is circulated in the order of the refrigerant outlets <NUM> of the heat sink <NUM>, the refrigerant transfer pipe <NUM>, and the refrigerant discharge port <NUM>.

<FIG> is an exploded perspective view of a cooling unit according to a preferred embodiment of the present invention. When describing the cooling unit with reference to <FIG>, the cooling unit <NUM> includes a heat sink <NUM>, a first heat dissipation plate <NUM>, and a second heat dissipation plate <NUM>.

The heat sink <NUM> is constituted by a pair of a lower plate <NUM>' and an upper plate <NUM>" in order to provide a space in which a refrigerant is circulated. Here, the lower plate <NUM>' is provided with a pair of a refrigerant inlet <NUM> and a refrigerant outlet <NUM> facing each other, to which the fastening holes <NUM> formed in the bottom surfaces of the side frames <NUM> are coupled, as previously described.

Meanwhile, the first heat dissipation plate <NUM> is located between the heat sink <NUM> and the battery modules <NUM>, and the second heat dissipation plate <NUM> is located under the heat sink <NUM>, whereby heat generated from the battery modules <NUM> is transmitted to the heat sink <NUM>.

Particularly, since the first heat dissipation plate <NUM> and the second heat dissipation plate <NUM> are located at the upper surface and the lower surface of the heat sink <NUM>, respectively, so as to wrap the heat sink <NUM> once more, there is an advantage in that, even in the case in which refrigerant leakage occurs, it is possible to prevent the refrigerant from permeating into the battery pack.

It is preferable for each of the heat sink <NUM>, the first heat dissipation plate <NUM>, and the second heat dissipation plate <NUM> to be made of a material that exhibits high thermal conductivity, such as aluminum.

<FIG> is a partial perspective view illustrating a battery pack according to a second preferred embodiment of the present invention.

Referring to <FIG>, the battery pack according to the second preferred embodiment of the present invention may further include a refrigerant circulation pipe <NUM>.

In the embodiment described with reference to <FIG>, a refrigerant is circulated along the refrigerant circulation channel <NUM> of the side frame <NUM>, whereas the refrigerant circulation pipe <NUM> is further provided in the second embodiment.

That is, the refrigerant transfer pipe <NUM> and the refrigerant circulation pipe <NUM> are connected to each other such that a refrigerant introduced into or discharged from the refrigerant transfer pipe <NUM> passes though the refrigerant circulation pipe <NUM>, and the refrigerant circulation pipe <NUM> is disposed in the refrigerant circulation channel <NUM> of the side frame <NUM>.

Since the refrigerant circulation pipe <NUM> is located in the refrigerant circulation channel <NUM>, as described above, it is possible to securely prevent leakage of the refrigerant, thus inhibiting occurrence of an event, even in the case in which the side case <NUM> is damaged due to external impact.

Claim 1:
A battery pack having a refrigerant circulation channel (<NUM>) provided in a pack case (<NUM>), the battery pack comprising:
at least one battery module (<NUM>);
a pack case configured (<NUM>) to receive the battery module (<NUM>) therein; and
a cooling unit (<NUM>) located between an inside upper surface of the pack case (<NUM>) and the battery module (<NUM>), the cooling unit (<NUM>) being configured to discharge heat generated from the battery module (<NUM>), wherein
the pack case (<NUM>) is provided with a refrigerant circulation channel (<NUM>) therein configured to supply and collect a refrigerant to and from the cooling unit (<NUM>),
wherein the pack case (<NUM>) comprises a front frame (<NUM>), a rear frame (<NUM>), and a pair of side frames (<NUM>) connecting the front frame (<NUM>) and the rear frame (<NUM>) to each other, and the refrigerant circulation channel (<NUM>) is provided in each of the pair of side frames (<NUM>),
characterized in that an air circulation channel (<NUM>) is located adjacent to the refrigerant circulation channel (<NUM>) of the side frame (<NUM>) so as to be parallel to the refrigerant circulation channel (<NUM>), and
wherein the air circulation channel (<NUM>) has at least one incision portion (<NUM>) configured to allow external air to pass therethrough.