Patent Description:
The present invention relates to a battery module and a battery pack including the same, and more particularly to a battery module configured such that the area of heat exchange between a battery cell, which generates heat, and a heat sink is increased and heat exchange between a busbar and the heat sink is also performed, whereby cooling performance of the battery module is improved, and a battery pack including the same.

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 this case, a problem, such as overload, may occur, since the plurality of battery cells is connected to each other. In particular, for the battery module, in which the plurality of battery cell is received, there is a problem in that temperature in the battery module increases due to overload, whereby abnormality of the battery is amplified. In order to solve this problem, a general battery module is provided with a heat sink configured to remove heat generated in a battery in order to maintain battery temperature.

<FIG> is a sectional view showing a cooling structure of a conventional battery module. As shown in <FIG>, the conventional battery module includes a plurality of battery cells <NUM> disposed perpendicular to a heat sink <NUM> and a pair of cooling plates <NUM> connected perpendicularly to the heat sink <NUM>, the cooling plates being in direct contact with a busbar assembly <NUM>.

The conventional battery module is configured to have a structure in which heat generated from the battery cells <NUM> and the busbar assembly <NUM> is removed by the heat sink <NUM> and the cooling plates <NUM>. However, a heat dissipation effect is low, and the size of the battery module is large.

That is, since the heat sink <NUM> and the battery cells <NUM> are in contact with each other in a state of being disposed perpendicular to each other, the area of contact therebetween is small, whereby it is difficult to rapidly remove heat generated from the battery cells <NUM> and a heat dissipation effect is low. Furthermore, separate cooling plates <NUM> and heat transfer members <NUM> are needed in order to cool the busbar assembly <NUM>, whereby the overall volume of the battery module is increased, and therefore energy density of the battery module is reduced.

Document <CIT> relates to a battery module configured by combining laminate type cells and a battery assembly including a stacked body in which a plurality of battery modules are stacked. Document <CIT> relates to a battery system that can be accommodated in a narrow space. Document <CIT> relates to a battery pack having an easily cooled structure.

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 module with improved cooling performance capable of inhibiting occurrence of a secondary problem due to heat generation by efficiently removing heat generated from a battery cell and a battery pack including the same.

It is another object of the present invention to provide a battery module with improved cooling performance capable of cooling a busbar using a battery cell cooling member, whereby an increase in volume of the battery module is minimized, and a battery pack including the same.

It is a further object of the present invention to provide a battery module with improved cooling performance capable of reducing a battery cell cooling deviation by increasing adhesion force and a battery pack including the same.

In order to accomplish the above objects, a battery module according to the present invention includes a heat sink (<NUM>) having a predetermined area, the heat sink being horizontally located; a support plate (<NUM>) including an upper support plate (<NUM>) and a lower support plate (<NUM>) located respectively at the upper surface and the lower surface of the heat sink (<NUM>); a battery cell (<NUM>) including a first battery cell (<NUM>) disposed in tight contact with the upper support plate (<NUM>) and a second battery cell (<NUM>) disposed in tight contact with the lower support plate (<NUM>); and a cover plate (<NUM>) including an upper cover plate (<NUM>) located above the first battery cell (<NUM>) and a lower cover plate (<NUM>) located under the second battery cell (<NUM>).

Also, in the battery module according to the present invention, the heat sink (<NUM>) is provided on the upper surface thereof with a protuberance (<NUM>) protruding by a predetermined height, and the upper support plate (<NUM>) is provided with a first opening (<NUM>) configured to receive the protuberance (<NUM>).

Also, in the battery module according to the present invention, the first battery cell (<NUM>) is located at the upper surface of the protuberance (<NUM>).

Also, in the battery module according to the present invention, the heat sink (<NUM>) may be provided on the lower surface thereof with a protuberance (<NUM>) protruding by a predetermined height, and the lower support plate (<NUM>) may be provided with a second opening (<NUM>) configured to receive the protuberance (<NUM>).

Also, in the battery module according to the present invention, the second battery cell (<NUM>) may be located at the lower surface of the protuberance (<NUM>).

Also, in the battery module according to the present invention, a thermally conductive resin layer may be interposed between the first battery cell (<NUM>) and the protuberance (<NUM>) and between the second battery cell (<NUM>) and the protuberance (<NUM>).

Also, in the battery module according to the present invention, first support frames (<NUM>) may be located between the upper support plate (<NUM>) and the upper cover plate (<NUM>) so as to extend along opposite edges of each thereof while having a predetermined height and width.

Also, in the battery module according to the present invention, a first support frame (<NUM>) may be located between the upper support plate (<NUM>) and the upper cover plate (<NUM>) so as to extend along the middle of each thereof while having a predetermined height and width.

Also, in the battery module according to the present invention, second support frames (<NUM>) may be located between the lower support plate (<NUM>) and the lower cover plate (<NUM>) so as to extend along opposite edges of each thereof while having a predetermined height and width.

Also, in the battery module according to the present invention, a second support frame (<NUM>) may be located between the lower support plate (<NUM>) and the lower cover plate (<NUM>) so as to extend along the middle of each thereof while having a predetermined height and width.

Also, in the battery module according to the present invention, a first busbar assembly (<NUM>) may be located between the upper support plate (<NUM>) and the upper cover plate (<NUM>).

Also, in the battery module according to the present invention, the first busbar assembly (<NUM>) may include a first busbar frame (<NUM>) having a first receiving recess (<NUM>(a)) formed therein and a busbar (<NUM>) seated in the first receiving recess (<NUM>(a)), the busbar (<NUM>) being configured to have a concave-convex structure that is bent at a predetermined angle a plurality of times.

Also, in the battery module according to the present invention, a second busbar assembly (<NUM>) may be located between the lower support plate (<NUM>) and the lower cover plate (<NUM>).

In addition, the present invention provides a battery pack including a battery module having at least one of the above-mentioned features.

In addition, the present invention provides a device including the battery pack.

As is apparent from the above description, a battery module with improved cooling performance according to the present invention and a battery pack including the same have an advantage in that relatively wide side surfaces of battery cells and a heat sink are in tight contact with each other in a state of being located in a horizontal direction, whereby cooling performance of the battery cells is improved due to an increase in heat transfer area.

In addition, the battery module with improved cooling performance according to the present invention and the battery pack including the same have a merit in that the heat sink, which is configured to cool the battery cells, and a busbar are in contact with each other, whereby no separate heat sink is necessary.

Furthermore, the battery module with improved cooling performance according to the present invention and the battery pack including the same have an advantage in that the battery cells, the heat sink, a support plate, etc. are fastened to each other via a plurality of support frames and fastening members, whereby it is possible to maintain uniform adhesion force between the battery cells and the heat sink while maximizing space utilization.

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.

Hereinafter, a battery module with improved cooling performance according to the present invention and a battery pack including the same will be described with reference to the accompanying drawings.

<FIG> is a perspective view of a battery pack according to a preferred embodiment of the present invention, <FIG> is an exploded perspective view of the battery pack shown in <FIG>, and <FIG> is a sectional view taken along line A-A' of <FIG>.

As shown in <FIG>, the battery pack according to the present invention is configured such that a plurality of battery modules <NUM> is horizontally stacked. The battery modules <NUM> are fixed using a plurality of fastening members B.

Here, each of the fastening members B may be, for example, a bolt provided with a screw thread, and a nut, which is fastened to the portion of the fastening member that protrudes from the lower surface of a lower cover plate <NUM> after being inserted through the battery pack, may be further provided.

Although not shown in the figures, the battery modules <NUM> may be received in a separate case (not shown) in the state in which the battery modules are fixed using the fastening members B. Depending on circumstances, after being received in the case (not shown), the battery modules <NUM> may be fixed together with the case (not shown) using the fastening members B.

<FIG> is an exploded perspective view of a battery module according to a preferred embodiment of the present invention. As shown in <FIG>, the battery module <NUM> includes a heat sink <NUM>, a support plate <NUM>, a busbar assembly <NUM>, a support frame <NUM>, battery cells <NUM>, and a cover plate <NUM>.

First, the heat sink <NUM> is a flat plate that is provided with a flow channel defined therein and has a predetermined area. A plurality of protuberances <NUM> is formed on the upper surface and the lower surface of the heat sink <NUM> so as to protrude therefrom in a state of being spaced apart from each other by a predetermined distance. The protuberances <NUM> will be described below in detail.

The support plate <NUM> includes an upper support plate <NUM> and a lower support plate <NUM> located at opposite surfaces of the heat sink <NUM>, more specifically the upper surface of the heat sink <NUM> and the lower surface of the heat sink <NUM>, respectively.

The busbar assembly <NUM> configured to electrically connect the battery cells <NUM> to each other includes a first busbar assembly <NUM> and a second busbar assembly <NUM>. The first busbar assembly <NUM> is located at the upper surface of the upper support plate <NUM>, and the second busbar assembly <NUM> is disposed at the lower surface of the lower support plate <NUM>.

A total of six first busbar assemblies <NUM>, one of which is located in the vicinity of each of opposite edges of the upper support plate <NUM> and four of which are located between the two first busbar assemblies located in the vicinity of the opposite edges of the upper support plate in a state of being spaced apart from each other by a predetermined distance in a longitudinal direction (an X-axis direction), are shown in the figure, which, however, is merely an example. The number or position of first busbar assemblies may be changed as long as the first busbar assemblies can be brought into tight contact with the upper support plate <NUM>.

The second busbar assemblies <NUM> are symmetrical with the first busbar assemblies <NUM>, and therefore an additional description thereof will be omitted.

Next, the support frame <NUM> includes first support frames <NUM> and second support frames <NUM>. The first support frames <NUM> are located between the upper support plate <NUM> and an upper cover plate <NUM>, and the second support frames <NUM> are located between the lower support plate <NUM> and the lower cover plate <NUM>. The first support frames and the second support frames will be described below in more detail.

The battery cells <NUM> include a plurality of first battery cells <NUM> and a plurality of second battery cells <NUM> located parallel to the heat sink <NUM>. Specifically, the first battery cells <NUM> are located between the upper support plate <NUM> and the upper cover plate <NUM>, and the second battery cells <NUM> are located between the lower support plate <NUM> and the lower cover plate <NUM>.

The first battery cells <NUM> and the second battery cells <NUM> may be battery cells having the same construction. For example, each battery cell may include a cell case, in which an electrode assembly (not shown) is received, and a pair of electrode leads.

Here, the electrode assembly may be a jelly-roll type 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 assembly 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 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 assembly, which is configured to have a structure in which battery 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 assembly or a laminated and stacked type 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 impact strength resistance, 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.

Meanwhile, the pair of electrode leads is constituted by a positive electrode lead and a negative electrode lead, which may be exposed from the cell case in a state of being electrically connected respectively to positive electrode tabs and negative electrode tabs of the electrode assembly or may be directly connected to the electrode assembly in the state in which tabs are omitted.

Next, the cover plate <NUM> serves to protect the battery cells <NUM> from the outside, and includes an upper cover plate <NUM> and a lower cover plate <NUM>.

Specifically, the upper cover plate <NUM> is located above the first battery cells <NUM> to protect the upper surfaces of the first battery cells <NUM>, and the lower cover plate <NUM> is located above the second battery cells <NUM> to protect the lower surfaces of the second battery cells <NUM>.

Each of the upper cover plate <NUM> and the lower cover plate <NUM> is provided with a plurality of through-holes formed so as to be spaced apart from each other by a predetermined distance such that the fastening members B are inserted therethrough.

<FIG> is a perspective view illustrating a coupling structure between the heat sink and the support plate in the battery module according to the preferred embodiment of the present invention.

Referring to <FIG>, the upper support plate <NUM> is located at the upper surface of the heat sink <NUM> according to the present invention, and the lower support plate <NUM> is located at the lower surface of the heat sink <NUM>.

Meanwhile, it is preferable for the protuberances <NUM> to be formed on the opposite surfaces of the heat sink <NUM>, i.e. the upper surface and the lower surface of the heat sink, so as to protrude therefrom by a predetermined height while having a predetermined shape. It is more preferable for the upper support plate <NUM> to have first openings <NUM> configured to receive the protuberances <NUM> formed on the upper surface of the heat sink <NUM> and for the lower support plate <NUM> to have second openings <NUM> configured to receive the protuberances <NUM> formed on the lower surface of the heat sink <NUM>.

When the upper support plate <NUM> and the lower support plate <NUM> are brought respectively into tight contact with the upper surface and the lower surface of the heat sink <NUM> having the protuberances <NUM> formed on the opposite surfaces thereof, the protuberances <NUM> formed on the upper surface of the heat sink <NUM> are inserted into the first openings <NUM>, and the protuberances <NUM> formed on the lower surface of the heat sink <NUM> are inserted into the second openings <NUM>, whereby rolling of the heat sink from side to side may be prevented.

Here, each of the upper support plate <NUM> and the lower support plate <NUM> may be made of a thermally conductive resin.

Meanwhile, a coolant inlet port <NUM> configured to supply a coolant is provided at one side of the heat sink <NUM>, and a coolant outlet port <NUM> configured to discharge the coolant that has performed heat exchange is provided in the vicinity of the coolant inlet port. It is obvious that the coolant inlet port <NUM> and the coolant outlet port <NUM> are not necessarily located so as to be adjacent to each other as long as it is possible to supply and discharge the coolant. In addition, the heat sink <NUM> and the support plate <NUM> are provided with through-holes, through which the fastening members B are inserted.

<FIG> is a perspective view illustrating a battery cell mounting structure in the battery module according to the preferred embodiment of the present invention, and <FIG> is a perspective view illustrating a support frame disposition structure in the battery module according to the preferred embodiment of the present invention.

The plurality of first battery cells <NUM> according to the present invention is horizontally seated on the protuberances <NUM> of the heat sink <NUM>, exposed to the outside in a state of being inserted through the first openings <NUM> of the upper support plate <NUM>, and the upper support plate <NUM>.

A conventional battery module is configured to have a structure in which battery cells are located perpendicular to a heat sink, whereby contact area between the battery cells and the heat sink is small, and therefore cooling performance of the battery module is limited.

In contrast, the battery module <NUM> according to the present invention is configured to have a structure in which the first battery cells <NUM> are located parallel to the heat sink <NUM> and in which the horizontal side surfaces of the first battery cells <NUM> contact the protuberances <NUM> of the heat sink <NUM>, whereby rapid heat transfer is achieved, and therefore heat transfer efficiency is improved.

Of course, it is obvious that the remaining portions of the first battery cells <NUM>, which are not in tight contact with the protuberances <NUM> of the heat sink <NUM>, are in tight contact with the upper support plate <NUM>.

Meanwhile, a known thermally conductive resin layer may be interposed between each of the protuberances <NUM> and a corresponding one of the first battery cells <NUM> in order to fix the protuberance and the first battery cell to each other.

The structure in which the second battery cells <NUM> and the lower support plate <NUM> are mounted is identical to the structure in which the first battery cells <NUM> and the upper support plate <NUM> are coupled to each other except for only difference in direction, and therefore a detailed description thereof will be omitted.

As previously described, the support frame <NUM> includes the first support frames <NUM> and the second support frames <NUM>.

The first support frames <NUM> are located between the upper support plate <NUM> and the upper cover plate <NUM>, more specifically at opposite edges and the middle of the upper support plate <NUM> in the longitudinal direction of the battery module (the X-axis direction). Each of the first support frames is a bar that has a predetermined width, height, and length and that has an approximately quadrangular section. Each of the first support frames <NUM> is provided with a plurality of first through-holes <NUM> formed so as to be spaced apart from each other by a predetermined distance such that the fastening members B can be inserted therethrough.

The second support frames <NUM> are identical in construction to the first support frames <NUM> except that the second support frames are located between the lower support plate <NUM> and the lower cover plate <NUM>. That is, each of the second support frames <NUM> is provided with a plurality of second through-holes <NUM> formed so as to be spaced apart from each other by a predetermined distance such that the fastening members B can be inserted therethrough.

Even though the plurality of battery modules <NUM> is fastened to each other in a state of being stacked, the support plate <NUM> and the cover plate <NUM> may be maintained spaced apart from each other by a predetermined distance by the first support frames <NUM> and the second support frames <NUM>, whereby it is possible to prevent the battery cells <NUM> from being pressed more than necessary and to inhibit local expansion at the time of swelling.

<FIG> is a perspective view illustrating a coupling structure between the battery cells and busbars in the battery module according to the preferred embodiment of the present invention.

When describing with further reference to <FIG>, the busbar assembly <NUM> includes a first busbar assembly <NUM> and a second busbar assembly <NUM>, which are identical in construction to each other except for only difference in disposition. Hereinafter, therefore, a description will be given based on the first busbar assembly <NUM>.

The first busbar assembly <NUM> includes a first busbar frame <NUM> and busbars <NUM>. The first busbar frame <NUM> is configured to electrically connect adjacent ones of the busbars <NUM> to each other while supporting the busbars <NUM>. The first busbar frame <NUM> is provided with first receiving recesses <NUM>(a) configured to receive the busbars <NUM> in a seated state and second receiving recesses <NUM>(b) depressed deeper than the first receiving recesses <NUM>(a).

Each of the busbars <NUM>, which is configured to have a concave-convex structure that is bent at a predetermined angle a plurality of times, includes a first horizontal portion <NUM>(a), a second horizontal portion <NUM>(b) located lower than the first horizontal portion <NUM>(a), and a connection portion <NUM>(c) configured to connect the first horizontal portion <NUM>(a) and the second horizontal portion <NUM>(b) to each other, the connection portion being bent at a predetermined angle.

When the busbar <NUM> having the above construction is seated in the receiving recesses of the first busbar frame <NUM>, the first horizontal portion <NUM>(a) is inserted into the first receiving recess <NUM>(a), and the second horizontal portion <NUM>(b) is inserted into the second receiving recess <NUM>(b), whereby the busbar <NUM> is securely fastened to the first busbar frame <NUM>.

Meanwhile, an electrode lead <NUM> of each of the first battery cells <NUM> is seated on the first horizontal portion <NUM>(a).

The conventional battery module has no function of cooling the busbar assembly <NUM> or further needs to have such a cooling function. In the present invention, however, the busbar assembly <NUM> is located in surface contact on the upper support plate <NUM> and the lower support plate <NUM> located respectively at the upper surface and the lower surface of the heat sink <NUM>, whereby it is possible to cool the busbar assembly <NUM> using only the heat sink <NUM>, which is configured to cool the battery cells, and therefore it is possible to minimize an increase in volume of the battery module.

The present invention may provide a battery pack including a battery module <NUM> having at least one of the above-mentioned features, and the battery pack may be mounted in a device, such as an electric vehicle, a hybrid electric vehicle, or a plug-in hybrid electric vehicle.

Claim 1:
A battery module comprising:
a heat sink (<NUM>) having a predetermined area, the heat sink being horizontally located;
a support plate (<NUM>) comprising an upper support plate (<NUM>) and a lower support plate (<NUM>) located respectively at an upper surface and a lower surface of the heat sink (<NUM>);
a battery cell (<NUM>) comprising a first battery cell (<NUM>) disposed in tight contact with the upper support plate (<NUM>) and a second battery cell (<NUM>) disposed in tight contact with the lower support plate (<NUM>); and
a cover plate (<NUM>) comprising an upper cover plate (<NUM>) located above the first battery cell (<NUM>) and a lower cover plate (<NUM>) located under the second battery cell (<NUM>),
characterized by
wherein the heat sink (<NUM>) is provided on the upper surface thereof with a protuberance (<NUM>) protruding by a predetermined height, and
wherein the upper support plate (<NUM>) is provided with a first opening (<NUM>) configured to receive the protuberance (<NUM>); and
wherein the first battery cell (<NUM>) is located at an upper surface of the protuberance (<NUM>).