Patent Description:
A secondary battery which has ease with applicability for various product groups and good electric characteristics such as high energy density is universally applied not only to portable devices but also electric vehicles (EV), hybrid electric vehicles (HEV), energy storage systems or the like, which are driven by an electric source. The secondary battery has a primary advantage of greatly reducing the use of fossil fuels and a secondary advantage of generating no byproduct after the use of energy, and thus the secondary battery receives attention as a new energy source which is environment-friendly and promotes energy efficiency.

A battery pack applied to an electric vehicle or the like includes a plurality of cell assembly connected in series, each cell assembly having a plurality of unit cells, in order to obtain high output. In addition, the unit cell includes positive and negative electrode current collectors, a separator, active materials, an electrolyte or the like and is capable of being repeatedly charged and discharged by means of electrochemical reactions among the components.

Meanwhile, recently, as the necessity for a large-capacity structure to be utilized as an energy storage is increasing, the demand for a battery pack having a multi-module structure in which a plurality of modules are aggregated is also increasing.

In the battery pack of a multi-module structure, a plurality of secondary batteries is densely arranged in a narrow space, and thus it is important to easily emit heat generated from each battery module.

In order to cool the battery pack, an indirect water-cooling method is used.

The indirect water-cooling method is used for preventing a battery module from generating heat by using a heat sink with a cooling channel, and in general case, a single heat sink is coupled to a lower end of the battery module to absorb heat of the battery module.

<FIG> and <FIG> are diagrams showing an existing heat sink applied for the indirect water-cooling method.

Referring to <FIG> and <FIG>, the existing heat sink <NUM> is coupled to a lower surface of a cell assembly <NUM> to cool the cell assembly <NUM>. A cooling channel is formed in the heat sink <NUM>, and a coolant inflow tube <NUM> and a coolant outlet tube <NUM> are also formed thereat. If a coolant flows into the coolant inflow tube <NUM>, the coolant circulates along the cooling channel formed in the heat sink <NUM> to cool the cell assembly <NUM> and flows out through the coolant outlet tube <NUM>.

However, the existing heat sink using the indirect water-cooling method has a problem in that its structure increases the entire height of a battery pack. In other words, since the upper surface of the existing heat sink <NUM> is closely coupled to a lower surface of the cell assembly <NUM>, the entire height of the battery pack increases.

In addition, if the upper surface of the heat sink <NUM> is coupled to the lower surface of the cell assembly <NUM>, a differential pressure increases at the coolant inflow tube <NUM> and the coolant outlet tube <NUM>. In detail, since the heat sink <NUM> is closely coupled to the lower surface of the cell assembly <NUM>, the coolant inflow tube <NUM> and the coolant outlet tube <NUM> are respectively bent twice, and due to such a bending structure, a differential pressure increases at the bent portions. In other words, the coolant inflow tube <NUM> and the coolant outlet tube <NUM> are firstly bent from a vertical direction to a horizontal direction and then secondly bent from the horizontal direction to the vertical direction, and due to such several bent portions, a differential pressure increases at the coolant inflow tube <NUM> and the coolant outlet tube <NUM>.

<CIT> discloses a battery module comprising a cell assembly including at least one unit cell and a heat sink comprising a coolant inflow tube and a coolant outlet tube.

The present disclosure is designed to solve the problems of the related art, and therefore the present disclosure is directed to providing a battery module comprising a cell assembly including at least one unit cell and a heat sink which may have improved space utilization.

In addition, the present disclosure is also directed to providing a battery module comprising a cell assembly including at least one unit cell and a heat sink which may have a reduced differential pressure by minimizing bending of a coolant inflow tube and a coolant outlet tube, and a battery module including the same.

Also, it will be easily understood that the objects and advantages of the present disclosure may be realized by the means shown in the appended claims.

In one aspect of the present disclosure, there is provided a battery module comprising a cell assembly including at least one unit cell and a heat sink for cooling a cell as defined in claim <NUM>.

A second connection port may be formed at the other end of the second cooling channel so that the other end of the second cooling channel is connected to the coolant connection tube through the second connection port.

Also, a first connection port may be formed at the other end of the first cooling channel so that the other end of the first cooling channel is connected to the coolant connection tube through the first connection port.

The coolant flowing in through the coolant inflow tube may pass through the second cooling channel, the coolant connection tube and the first cooling channel, and then flow out through the coolant outlet tube.

In the present disclosure, since heat sinks are coupled to both sides of a cell assembly, a Z-axial space of a battery pack may be ensured without increasing the height of the battery pack.

In particular, in the present disclosure, since a plurality of heat sinks is designed to commonly use a single coolant inflow tube and a single coolant outlet tube, it is possible to further enhance space utilization of the battery module and reduce manufacture costs of the battery module.

In addition, in the present disclosure, since the cell assembly is cooled by means of a plurality of heat sinks installed at both sides thereof, it is possible to improve the cooling efficiency of the battery module in comparison to an existing indirect water-cooling method.

Further, in the present disclosure, since bending of the coolant inflow tube and the coolant outlet tube is minimized, it is possible to reduce a differential pressure occurring in the coolant inflow tube and the coolant outlet tube.

The accompanying drawings illustrate a preferred embodiment of the present disclosure and together with the foregoing disclosure, serve to provide further understanding of the technical scope of the present disclosure, and thus, the present disclosure is not construed as being limited to the drawing.

The above objects, features and advantages of the present disclosure will become apparent from the following descriptions of the embodiments with reference to the accompanying drawings, from which it will be deemed that a person having ordinary skill can easily practice the technical features of the present disclosure. Also, any explanation of the prior art known to relate to the present disclosure may be omitted if it is regarded to render the subject matter of the present disclosure vague. Hereinafter, an embodiment of the present disclosure will be described in detail with reference to the accompanying drawings.

<FIG> is an exploded view showing a cell assembly and a heat sink according to an embodiment of the present disclosure.

<FIG> is a diagram showing a battery module to which the cell assembly and the heat sink are coupled according to an embodiment of the present disclosure.

Referring to <FIG> and <FIG>, a battery module <NUM> according to the present disclosure includes a cell assembly <NUM> and a plurality of heat sinks <NUM>, <NUM>.

The cell assembly <NUM> is a module in which a plurality of unit cells <NUM> are stacked laterally and connected in series or in parallel, and electrode leads may be exposed at its sides.

The unit cell <NUM> is configured so that cells, each having a negative electrode plate, a separator and a positive electrode plate, are repeatedly stacked.

The cell assembly <NUM> includes at least one unit cell <NUM>, and the kind of the unit cell is not specially limited. Each unit cell <NUM> may be configured with a lithium ion battery cell, a lithium polymer battery cell, a nickel cadmium battery cell, a nickel hydrogen battery cell, a nickel zinc battery cell or the like, which is rechargeable and also needs to consider a charge or discharge voltage. In addition, the number of unit cells <NUM> included in the cell assembly <NUM> may be set variously depending on a demanded output voltage or charge/discharge capacity. However, the present disclosure is not limited by the kind, output voltage, charge/discharge capacity or the lie of the unit cell <NUM>. In addition, the present disclosure is not limited by an electric connection method of the unit cell <NUM>.

Each of the heat sinks <NUM>, <NUM> is used for cooling the cell assembly <NUM> in an indirect water-cooling method and is made of a material with excellent thermal conductivity (for example, aluminum or the like). Also, cooling channels <NUM>, <NUM> serving as passages of the coolant are formed in the heat sinks <NUM>, <NUM>.

The cooling channels <NUM>, <NUM> formed in each of the heat sinks <NUM>, <NUM> may be shaped as shown in <FIG> and <FIG> in the heat sinks <NUM>, <NUM>, or cooling channels <NUM>, <NUM> of various shapes may also be formed in each of the heat sinks <NUM>, <NUM>. In addition, cooling channels of different shapes may be formed in the first heat sink <NUM> and the second heat sink <NUM>.

A plurality of through holes <NUM> is formed in the first heat sink <NUM> so that a coupling member such as a bolt may be inserted therein, and if the coupling member is inserted into and coupled to the through hole <NUM>, the first heat sink <NUM> is closely coupled to one side of the cell assembly <NUM>. The first heat sink <NUM> is coupled to one side of the cell assembly <NUM> to absorb and dissipate heat energy generated at the unit cell <NUM> of the cell assembly <NUM> by means of the coolant flowing through the cooling channel <NUM>.

A coolant outlet tube <NUM> is formed at one end of the cooling channel <NUM> of the first heat sink <NUM>, and a connection port <NUM> is formed at the other end of the cooling channel <NUM>.

The coolant outlet tube <NUM> may be designed with a pipe shape of a predetermined length, and has a space therein so that the coolant may flow. One end of the coolant outlet tube <NUM> is connected to one end of the cooling channel <NUM>, and a coolant outlet b is formed at the other end of the coolant outlet tube <NUM>.

In addition, one end of the coolant outlet tube <NUM> may also be connected to one end of the cooling channel <NUM> by means of welding, coupling or the like. In addition, the coolant outlet tube <NUM> and the cooling channel <NUM> may also be integrally fabricated.

The connection port <NUM> formed at the other end of the cooling channel <NUM> of the first heat sink <NUM> is coupled to the coolant connection tube <NUM> by means of welding, coupling or the like, thereby forming a passage for the coolant between the cooling channel <NUM> and the coolant connection tube <NUM>. The coolant transferred through the coolant connection tube <NUM> flows into the cooling channel <NUM> of the first heat sink <NUM>.

The coolant outlet tube <NUM> extends horizontally toward the second heat sink <NUM>, and is bent in a vertical direction at a point adjacent to the second heat sink <NUM> and then extends again, so that the coolant outlet b is adjacent to a coolant inlet a. Since the coolant outlet b and the coolant inlet a are located adjacent to each other, it is easier to control flowing-in and flowing-out of the coolant. In addition, since the coolant outlet tube <NUM> is bent once in a downward direction, the number of bending is reduced in comparison to an existing heat sink, and thus a differential pressure in the coolant outlet tube <NUM> is also reduced.

By means of the connection structure of the coolant outlet tube <NUM> and the cooling channel <NUM> of the first heat sink <NUM>, the coolant circulating through the cooling channel <NUM> of the first heat sink <NUM> flows out through the coolant outlet tube <NUM>.

Similarly, a plurality of through holes <NUM> is formed in the second heat sink <NUM> so that a coupling member such as a bolt may be inserted therein, and if the coupling member is inserted into and coupled to the through hole <NUM>, the second heat sink <NUM> is closely coupled to the other side of the cell assembly <NUM>. The first heat sink <NUM> is coupled to one side of the cell assembly <NUM>, and the second heat sink <NUM> is coupled to the other side of the cell assembly <NUM>, which is opposite to one side thereof, to absorb and dissipate heat energy generated at the unit cell <NUM> of the cell assembly <NUM> by means of the coolant flowing through the cooling channels <NUM>, <NUM>.

A coolant inflow tube <NUM> is formed at one end of the cooling channel <NUM> of the second heat sink <NUM>, and a connection port <NUM> is formed at the other end of the cooling channel <NUM>.

The coolant inflow tube <NUM> may be designed with a pipe shape of a predetermined length, and has a space therein so that the coolant may flow. One end of the coolant inflow tube <NUM> is coupled to one end of the cooling channel <NUM>, and a coolant inlet a is formed at the other end of the coolant inflow tube <NUM>. One end of the coolant inflow tube <NUM> may be connected to one end of the cooling channel <NUM> by means of welding, coupling or the like. In addition, the coolant inflow tube <NUM> and the cooling channel <NUM> may also be integrally fabricated.

The connection port <NUM> formed at the other end of the cooling channel <NUM> of the second heat sink <NUM> is coupled to the coolant connection tube <NUM> by means of welding, coupling or the like, thereby forming a passage for the coolant between the cooling channel <NUM> and the coolant connection tube <NUM> and also providing the coolant circulating through the cooling channel <NUM> to the coolant connection tube <NUM>.

The coolant inflow tube <NUM> is bent into a vertical downward direction and extends so that the coolant inlet a is formed downwards. In particular, since the coolant inflow tube <NUM> is bent just once, the number of bending is reduced in comparison to an existing heat sink, and thus a differential pressure in the coolant outlet tube <NUM> is also reduced.

By means of the connection structure of the coolant inflow tube <NUM>, the cooling channel <NUM> of the second heat sink <NUM> and the coolant connection tube <NUM>, the coolant flowing in through the coolant inlet a passes through the cooling channel <NUM> of the second heat sink <NUM> and the coolant connection tube <NUM>.

In addition, by means of the connection structure of the first heat sink <NUM>, the second heat sink <NUM> and the coolant connection tube <NUM>, the battery module <NUM> including a plurality of heat sinks <NUM>, <NUM> has just a single coolant inlet a, a single coolant inflow tube <NUM>, a single coolant outlet b and a single coolant outlet tube <NUM>. In other words, a single coolant inlet a, a single coolant inflow tube <NUM>, a single coolant outlet b and a single coolant outlet tube <NUM> are commonly used for the first heat sink <NUM> and the second heat sink <NUM>.

The coolant flowing into the coolant inflow tube <NUM> absorbs heat of the unit cells <NUM> while passing through the cooling channel <NUM> of the second heat sink <NUM>, the coolant connection tube <NUM>, and the cooling channel <NUM> of the first heat sink <NUM>, and then flows out through the coolant outlet tube <NUM>.

Meanwhile, in the above embodiment, it has been described that the coolant outlet tube <NUM> extends horizontally toward the second heat sink <NUM> and is bent into a vertical downward direction at a point adjacent to the second heat sink <NUM> so that the coolant outlet b and the coolant inlet a are adjacent to each other. However, it is also possible that the coolant inflow tube <NUM> extends horizontally toward the first heat sink <NUM>, and is bent into a vertical downward direction at a point adjacent to the first heat sink <NUM> and vertically extends downwards.

In other words, as another embodiment, the coolant outlet tube <NUM> may be directly bent into a vertical downward direction without extending horizontally, and also the coolant inflow tube <NUM> may extends horizontally toward first heat sink <NUM> and is bent into a vertical downward direction at a point adjacent to the first heat sink <NUM>. In another embodiment, the coolant inlet and the coolant outlet may be located adjacent to the first heat sink <NUM>. In still another embodiment, both the coolant outlet tube <NUM> and the coolant inflow tube <NUM> may extend horizontally and are then bent into a vertical downward direction at a specific point (for example, an intermediate point between the first heat sink and the second heat sink) and extends, so that the coolant inlet and the coolant outlet are located adjacent to each other.

The battery module <NUM> according to an embodiment of the present disclosure may be used as a component of a battery pack including a plurality of battery modules and a battery management system for controlling charge/discharge of the battery modules. The battery pack according to an embodiment of the present disclosure may be used as a component of a battery-driven system including the battery pack and a load which is supplied with power from the battery pack.

The battery-driven system may be an electric vehicle (EV), a hybrid electric vehicle (HEV), an electric bike (E-Bike), a power tool, an energy storage system, an uninterrupted power supply, a portable computer, a portable phone, a portable audio device, a portable video device or the like. The load may be a motor for giving a rotational force by the power supplied from the battery pack or a power conversion circuit for converting the power supplied from the battery pack into a power necessary to various circuit components.

As described above, in the battery module <NUM> according to an embodiment of the present disclosure, since the heat sinks <NUM>, <NUM> are coupled to both sides of the cell assembly <NUM>, a Z-axial space of a battery pack may be ensured without increasing the height of the battery pack. In addition, in the battery module <NUM> according to an embodiment of the present disclosure, since a plurality of heat sinks <NUM>, <NUM> is designed to commonly use a single coolant inflow tube <NUM> and a single coolant outlet tube <NUM>, it is possible to further enhance space utilization and reduce manufacture costs of the battery module. Moreover, since the cell assembly <NUM> of the battery module <NUM> is cooled by means of the plurality of heat sinks <NUM>, <NUM> installed at both sides thereof, it is possible to improve the cooling efficiency in comparison to an existing indirect water-cooling method. Further, in the battery module <NUM>, since bending of the coolant inflow tube <NUM> and the coolant outlet tube <NUM> is minimized, it is possible to reduce a differential pressure occurring in the coolant inflow tube <NUM> and the coolant outlet tube <NUM>.

Claim 1:
A battery module comprising a cell assembly (<NUM>) including at least one unit cell (<NUM>) and a heat sink (<NUM>, <NUM>) for cooling the cell assembly (<NUM>), the heat sink comprising:
a first heat sink (<NUM>) coupled to one side of the cell assembly (<NUM>) and having a first cooling channel (<NUM>) through which a coolant passes; and
a second heat sink (<NUM>) coupled to the other side of the cell assembly (<NUM>) and having a second cooling channel (<NUM>) through which the coolant passes,
wherein the second heat sink (<NUM>) includes a coolant inflow tube (<NUM>) connected to one end of the second cooling channel (<NUM>),
wherein the first heat sink (<NUM>) includes a coolant outlet tube (<NUM>) connected to one end of the first cooling channel (<NUM>), and
wherein the other end of the second cooling channel (<NUM>) is connected to a coolant connection tube (<NUM>), and the other end of the first cooling channel (<NUM>) is connected to the coolant connection tube (<NUM>),
characterized in that
the coolant outlet tube (<NUM>) is directly bent into a vertical downward direction without extending horizontally, and the coolant inflow tube (<NUM>) extends horizontally from the second heat sink (<NUM>) toward first heat sink (<NUM>) and is bent into a vertical downward direction at a point adjacent to the first heat sink (<NUM>) so that a coolant inlet (a) and a coolant outlet (b) are formed at adjacent locations, or
the coolant outlet tube (<NUM>) and the coolant inflow tube (<NUM>) extend horizontally from, respectively, the first heat sink (<NUM>) and the second heat sink (<NUM>) towards, respectively, the second heat sink (<NUM>) and the first heat sink (<NUM>), and are then bent into a vertical downward direction and extends, so that a coolant inlet (a) and a coolant outlet (b) are formed at adjacent locations.