Patent Description:
The present disclosure relates to a battery module and a battery pack including the same, and more particularly, to a battery module having novel cooling structure and a battery pack including the same.

Along with the technology development and increased demand for mobile devices, demand for secondary batteries as energy sources has been increasing rapidly. In particular, a secondary battery has attracted considerable attention as an energy source for power-driven devices, such as an electric bicycle, an electric vehicle, and a hybrid electric vehicle, as well as an energy source for mobile devices, such as a mobile phone, a digital camera, a laptop computer and a wearable device.

Small-sized mobile devices use one or several battery cells for each device, whereas middle or large-sized devices such as vehicles require high power and large capacity. Therefore, a middle or large-sized battery module having a plurality of battery cells electrically connected to one another is used.

Since the middle or large-sized battery module is preferably manufactured so as to have as small a size and weight as possible, a prismatic battery, a pouch-shaped battery or the like, which can be stacked with high integration and has a small weight relative to capacity, is mainly used as a battery cell of the middle or large-sized battery module. Such a battery module has a structure in which a plurality of cell assemblies including a plurality of unit battery cells are connected in series in order to obtain high output. And, the battery cell includes positive electrode and negative electrode current collectors, a separator, an active material, an electrolyte solution, and the like, and thus can be repeatedly charged and discharged by an electrochemical reaction between components.

Meanwhile, recently, along with a continuous rise of the necessity for a large-capacity secondary battery structure, including the utilization of the secondary battery as an energy storage source, there is a growing demand for a battery pack of a multi-module structure which is an assembly of battery modules in which a plurality of secondary batteries are connected in series or in parallel.

Meanwhile, when a plurality of battery cells are connected in series or in parallel to configure a battery pack, a method of first configuring a battery module composed of at least one battery cell and then adding other components to at least one battery module to configure a battery pack is common.

<FIG> shows a part of a perspective view according to a conventional battery module. <FIG> is an enlarged view showing a part of a cross-sectional view taken along the xy plane with reference to the cutting line A-A' of <FIG>.

Referring to <FIG> and <FIG>, the conventional battery module includes a battery cell assembly consisting of a plurality of battery cells <NUM> stacked on each other, and a busbar assembly that electrically connects the electrode leads <NUM> of the plurality of battery cells <NUM> to each other, a module frame <NUM> that wraps the battery cell assembly, and an external frame <NUM> that covers a busbar assembly. Here, the busbar assembly includes a busbar frame <NUM> having lead slots that allow the discrete passage of the electrode leads <NUM> of each battery cell <NUM>, and busbar slots mounted on the busbar frame <NUM> and provided so as to correspond to the number of lead slots, and further includes a busbar <NUM> that is connected to the electrode leads passing through the busbar slots by welding, etc. Further, a cooling fin <NUM> may be arranged between the battery cells <NUM> of the battery cell assembly.

At this time, the busbar <NUM> is separated from the cooling fin <NUM> by the busbar frame <NUM>, so that heat generated in the busbar <NUM> cannot be directly transferred to the cooling fin <NUM>. Instead, the heat generated in the busbar <NUM> is transferred via the electrode leads <NUM>, transferred to the cooling fin <NUM>, and then transferred via a thermal conductive resin layer formed on the bottom part of the battery cell <NUM> and the module frame <NUM>.

Recently, there is a tendency to continuously increase the necessity for high capacity, high energy, fast charging, etc. and also increase the amount of current flowing through the busbar. The high current flowing through the busbar causes heat generation in the busbar, and such heat generation is difficult to effectively cool through the conventional cooling structure alone. Therefore, in order to cool the heat generation, there is a need for a structure that can make a direct contact with the busbar to cool the busbar.

It is an object of the present disclosure to provide a battery module that can solve the heat generation problem of the busbar and a battery pack including the same.

However, the objects of the present disclosure are not limited to the aforementioned objects, and other objects which are not described herein should be clearly understood by those skilled in the art from the following detailed description and the accompanying drawings.

According to the present disclosure, there is provided a battery module comprising: a battery cell stack in which a plurality of battery cells are stacked, a module frame that wraps the battery cell stack, a busbar frame that covers a portion of the battery cell stack exposed from the module frame, a busbar that is connected to an electrode lead protruding from the battery cell stack via a first slot formed in the busbar frame, and a cooling fin that is located between battery cells adj acent to each other among the plurality of battery cells, wherein the busbar is connected to the cooling fin.

The battery module may further include a heat transfer member located between the busbar and the cooling fin.

The busbar frame may further include a second slot, and the heat transfer member may be formed adjacent to the second slot to come into contact with the busbar.

The cooling fin may be inserted into the second slot to come into contact with the heat transfer member.

The heat transfer member may be formed of a material having electrical insulating properties and thermal conductivity.

The heat transfer member may be surface-joined with the busbar.

The cooling fin may be surface-joined with the heat transfer member.

The battery module may further include a thermal conductive resin layer located on the bottom part of the module frame, wherein the cooling fin may be contact with the thermal conductive resin layer, and the heat generated from the busbar may be sequentially transferred to the heat transfer member, the cooling fin, and the thermal conductive resin layer.

The module frame of the battery module according to another embodiment of the present disclosure may include a structure that is opened in the upper and lower surfaces and wraps all side surface parts of the battery cell stack.

The battery module may further include a cooling plate located at the lower end of the thermal conductive resin layer, wherein the thermal conductive resin layer may come into contact with the cooling plate, and the heat transferred to the thermal conductive resin layer may be transferred to the cooling plate.

According to another embodiment of the present disclosure, there is provided a battery pack comprising the above-mentioned battery module.

According to the present disclosure, the problem of heat generation of the busbar in a high current and fast charging environment can be solved by a novel type of busbar cooling structure. Additionally, the stability of the battery module can be improved by solving the heat generation problem.

Hereinafter, various embodiments of the present disclosure will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily carry out them. The present disclosure can be modified in various different ways, and is not limited to the embodiments set forth herein.

A description of parts not related to the description will be omitted herein for clarity, and like reference numerals designate like elements throughout the description.

In addition, it will be understood that when an element such as a layer, film, region, or plate is referred to as being "on" or "above" another element, it can be directly on the other element or intervening elements may also be present. In contrast, when an element is referred to as being "directly on" another element, it means that other intervening elements are not present. Further, the word "on" or "above" means disposed on or below a reference portion, and does not necessarily mean being disposed "on" or "above" the reference portion toward the opposite direction of gravity.

Further, throughout the specification, when a portion is referred to as "including" or "comprising" a certain component, it means that the portion can further include other components, without excluding the other components, unless otherwise stated.

Further, throughout the specification, when referred to as "planar", it means when a target portion is viewed from the upper side, and when referred to as "cross-sectional", it means when a target portion is viewed from the side of a cross section cut vertically.

The terms "first," "second," etc. are used to explain various components, but the components should not be limited by the terms. These terms are only used to distinguish one component from the other component.

Now, a battery module according to an embodiment of the present disclosure will be described with reference to <FIG>.

<FIG> is an exploded perspective view of a battery module according to an embodiment of the present disclosure. <FIG> is a perspective view showing a state in which the components of the battery module of <FIG> are combined. <FIG> is a perspective view showing one battery cell included in the battery cell stack of <FIG>.

Referring to <FIG> and <FIG>, the battery module <NUM> according to an embodiment of the present disclosure may include a battery cell stack <NUM> in which a plurality of battery cells <NUM> are stacked, a module frame that wraps the battery cell stack <NUM>, an upper plate <NUM> that covers the upper part of the battery cell stack <NUM>, end plates <NUM> that are respectively located on the front and rear surfaces of the battery cell stack <NUM>, and a busbar frame <NUM> that is located between the battery cell stack <NUM> and the end plate <NUM>. At this time, the module frame may include a U-shaped frame <NUM> of which an upper surface, a front surface and a rear surface are opened. Further, the battery module <NUM> includes a thermal conductive resin layer <NUM> located between the U-shaped frame <NUM> and the battery cell stack <NUM>. The thermal conductive resin layer <NUM> is a kind of heat dissipation layer, and may be formed by applying a material having a heat dissipation function. The end plate <NUM> may be formed of a metal material.

When opened both sides of the U-shaped frame <NUM> are referred to as a first side and a second side, respectively, the U-shaped frame <NUM> has a plate-shaped structure that is bent so as to continuously warp the front, lower and rear surfaces adjacent to each other among the remaining outer surfaces excluding surfaces of the battery cell stack <NUM> corresponding to the first side and the second side. The upper surface corresponding to the lower surface of the U-shaped frame <NUM> is opened.

The upper plate <NUM> has a single plate-shaped structure that covers the remaining upper surface excluding the front, lower and rear surfaces which are wrapped by the U-shaped frame <NUM>. The U-shaped frame <NUM> and the upper plate <NUM> can be coupled by welding or the like in a state in which the corresponding edge areas are in contact with each other, thereby forming a structure wrapping the battery cell stack <NUM>. That is, the U-shaped frame <NUM> and the upper plate <NUM> can have a coupling part CP formed by a coupling method such as welding at an edge area corresponding to each other.

The battery cell stack <NUM> includes a plurality of battery cells <NUM> stacked in one direction, and the plurality of battery cells <NUM> may be stacked in the y-axis direction as shown in <FIG>. In other words, a direction in which the plurality of battery cells <NUM> are stacked may be the same as a direction in which two side surface parts of the U-shaped frame <NUM> face each other.

The battery cell <NUM> is preferably a pouch type battery cell. For example, referring to <FIG>, the battery cell <NUM> according to the present embodiment may have a structure in which the two electrode leads <NUM> and <NUM> protrude from one end part 114a and the other end part 114b of the battery main body <NUM> toward mutually opposite directions, respectively. The battery cell <NUM> can be manufactured by joining both end parts 114a and 114b of the cell case <NUM> and both side surfaces 114c connecting them in a state in which an electrode assembly (not shown) is housed in the cell case <NUM>. In other words, the battery cell <NUM> according to the present embodiment has a total of three sealing parts 114sa, 114sb and 114sc, wherein the sealing parts 114sa, 114sb and 114sc have a structure that is sealed by a method such as heat fusion, and the remaining other side part may be formed of a connection part <NUM>. Between both end parts 114a and 114b of the battery case <NUM> is defined as a longitudinal direction of the battery cell <NUM>, and between the one side surface 114c and the connection part <NUM> that connect both end parts 114a and 114b of the battery case <NUM> is defined as a width direction of the battery cell <NUM>.

The connection part <NUM> is a region that extends long along one edge of the battery cell <NUM>, and a protrusion part 110p of the battery cell <NUM> may be formed at an end part of the connection part <NUM>. The protrusion part 110p may be formed on at least one of both end parts of the connection part <NUM> and may protrude in a direction perpendicular to the direction in which the connection part <NUM> extends. The protrusion part 110p may be located between one of the sealing parts 114sa and 114sb of both end parts 114a and 114b of the battery case <NUM>, and the connection part <NUM>.

The cell case <NUM> is generally formed of a laminated structure of a resin layer/metallic thin film layer/resin layer. For example, a surface of the battery case formed of an O(oriented)-nylon layer tends to slide easily by an external impact when a plurality of battery cells are stacked in order to form a medium- or large-sized battery module. Therefore, in order to prevent this sliding and maintain a stable stacked structure of the battery cells, an adhesive member, for example, a sticky adhesive such as a double-sided tape or a chemical adhesive coupled by a chemical reaction upon adhesion, can be attached to the surface of the battery case to form the battery cell stack <NUM>. In the present embodiment, the battery cell stack <NUM> may be stacked in a y-axis direction and housed into the U-shaped frame <NUM> in a z-axis direction. As a comparative example thereto, there is a case in which the battery cells are formed as cartridge-shaped components so that fixing between the battery cells leads to assembling by the battery module frame. In this comparative example, due to the presence of the cartridge-shaped components, there is almost no cooling action or the cooling may be proceeded in a surface direction of the battery cells, whereby the cooling does not well perform toward a height direction of the battery module.

Referring to <FIG>, the U-shaped frame <NUM> according to the present embodiment includes a bottom part and two side surface parts facing each other connected by the bottom part. Before the battery cell stack <NUM> is mounted on the bottom part of the U-shaped frame <NUM>, a thermal conductive resin is applied to the bottom part of the U-shaped frame <NUM>, and the thermal conductive resin can be cured to form a thermal conductive resin layer <NUM>. The thermal conductive resin layer <NUM> is located between the bottom part of the U-shaped frame <NUM> and the battery cell stack, and can serve to transfer heat generated in the battery cell <NUM> to the bottom of the battery module <NUM> and fix the battery cell stack <NUM>.

<FIG> is an enlarged view showing a part of a cross-sectional view taken along the xy plane with reference to the cutting line B-B' of <FIG>. <FIG> shows the upper cross-section in <FIG> as viewed from above. <FIG> is an enlarged view showing a part of a cross-sectional view taken along the xz plane with reference to the cutting line C-C' of <FIG>.

The conventional battery module does not have a direct cooling path for the busbar, and thus, heat generated by the busbar was emitted only by a path connecting to the busbar, electrode leads, battery cells, cooling fins, and thermal conductive resin layer. However, in a situation where a high heat generation of the busbar is made for a short time by the flow of high current, similarly to rapid charging, a cooling structure capable of minimizing the temperature rise of the busbar was needed.

Therefore, referring to <FIG>, the battery module <NUM> according to the present embodiment includes a busbar frame <NUM> that covers a portion of the battery cell stack <NUM> exposed from the module frame <NUM>, a busbar <NUM> that is connected to the electrode lead <NUM> protruding from the battery cell stack via a first slot <NUM> formed in the busbar frame <NUM>, and a cooling fin <NUM> that is located between battery cells <NUM> adjacent to each other among the plurality of battery cells <NUM>. At this time, the busbar <NUM> is connected to the cooling fin <NUM>. Further, the battery module <NUM> according to the present embodiment may further include a heat transfer member <NUM> located between the busbar <NUM> and the cooling fin <NUM>. In a modified embodiment, the heat transfer member <NUM> may be omitted, and the cooling fin <NUM> may be in direct contact with the busbar <NUM>.

The busbar frame <NUM> according to the present embodiment may further include a second slot <NUM>. The heat transfer member <NUM> may be formed so as to be adjacent to the second slot <NUM> of the busbar frame <NUM> to come into contact with the busbar <NUM>. Also, the cooling fin <NUM> may be inserted into the second slot <NUM> to come into contact with the heat transfer member <NUM>. Further, the cooling fin <NUM> may further come into contact with the second slot <NUM> and the busbar frame <NUM>. Successive heat transfer of the busbar <NUM>, heat transfer member <NUM> and cooling fin <NUM>, or successive heat transfer of the busbar <NUM>, heat transfer member <NUM>, cooling fin <NUM> and busbar frame <NUM> can be made through the contacts.

The heat transfer member <NUM> according to the present embodiment may be formed of a material having electrical insulation properties and thermal conductivity. Specifically, the heat transfer member <NUM> may include one of a heat transfer pad and a thermal conductive resin layer. Therefore, the heat transfer member <NUM> may enable heat conduction while maintaining insulation properties between the busbar <NUM> and the cooling fin <NUM>.

The heat transfer member <NUM> may be surface-joined with the busbar <NUM>. Also, the cooling fin <NUM> may be surface-joined with the heat transfer member <NUM>. Therefore, heat in the busbar <NUM> may be transferred to the cooling fin <NUM> by the busbar <NUM>, the heat transfer member <NUM>, and the cooling fins <NUM> that are surface-joined as described above.

At this time, the battery module according to the present embodiment may further include a thermal conductive resin layer <NUM> that is located on the bottom part of the module frame, particularly the U-shaped frame <NUM> of the module frame. The cooling fins <NUM> may come into contact with the thermal conductive resin layer <NUM>. A cooling plate <NUM> as a pack component or a cooling plate <NUM> integrally formed with the battery module may be formed under the bottom part of the U-shaped frame <NUM> included in the battery module according to the present embodiment. The heat transferred to the cooling fin <NUM> is transferred to the thermal conductive resin layer <NUM>, transferred from the thermal conductive resin layer <NUM> to the cooling plate <NUM> to be discharged. Therefore, the heat generated from the busbar <NUM> may be sequentially transferred to the heat transfer member <NUM>, the cooling fins <NUM>, the thermal conductive resin layer <NUM>, and the cooling plate <NUM> to be discharged. Through the sequential delivery and release structure as described above, heat from the busbar generated in a high current situation such as rapid charging can be effectively dissipated, and the stability of the battery module can be secured.

The cooling fin <NUM> according to the present embodiment can not only directly cool the busbar <NUM>, but also transfer and cool the heat generated in the battery cell <NUM> to the thermal conductive resin layer <NUM> and the cooling plate <NUM>, and thus, dual cooling can be made. Further, the busbar <NUM> is thermally connected to the battery cell <NUM> having high specific heat and thermal capacity via the cooling fin <NUM>, so that not only it slows down the temperature rise rate of the busbar <NUM>, but also the resistance can be lowered by keeping the temperature of the busbar <NUM> rather high when the outside air temperature is low. Thereby, the energy efficiency can be increased.

Next, a battery module according to another embodiment of the present disclosure will be described with reference to <FIG>.

<FIG> is an exploded perspective view showing a part of a battery module according to another embodiment of the present disclosure. Since contents overlapping with the contents of the above-mentioned battery module exist herein, only the contents different from those concerning the above-mentioned will be described.

Referring to <FIG>, the module frame of the present disclosure may be a wrapping frame <NUM> that is opened in the upper and lower surfaces, and wraps all side surface parts of the battery cell stack <NUM>. Since the wrapping frame <NUM> is opened in both the upper and lower surfaces, the thermal conductive resin layer <NUM> may be formed at a position corresponding to the lower surface of the wrapping frame <NUM>. The battery module <NUM> of the present disclosure includes a wrapping frame <NUM>, whereby it can maximize the contact between the battery cell stack <NUM> and the thermal conductive resin layer <NUM> and between the cooling fins <NUM> and the thermal conductive resin layer <NUM> to maximize heat transfer and heat dissipation.

At this time, the battery module <NUM> of the present disclosure may further include a cooling plate <NUM> that is located at the lower end of the thermal conductive resin layer <NUM>. The thermal conductive resin layer <NUM> may further come into contact with the cooling plate to conduct heat transfer. Accordingly, the effect that heat transfer is maximized can be achieved.

The above-mentioned battery module can be included in the battery pack. The battery pack may have a structure in which one or more of the battery modules according to the embodiment of the present disclosure are gathered, and packed together with a battery management system (BMS) and a cooling device that control and manage battery's temperature, voltage, etc..

Claim 1:
A battery module comprising:
a battery cell stack in which a plurality of battery cells are stacked,
a module frame that wraps the battery cell stack,
a busbar frame that covers a portion of the battery cell stack exposed from the module frame,
a busbar that is connected to an electrode lead protruding from the battery cell stack via a first slot formed in the busbar frame, and
a cooling fin that is located between battery cells adjacent to each other among the plurality of battery cells,
wherein the busbar is connected to the cooling fin.