Patent Description:
The present disclosure relates to a battery pack including at least one battery module, and more particularly to a battery pack with at least one battery module having improved space utilization.

In modern society, as portable devices such as a mobile phone, a notebook computer, a camcorder and a digital camera has been daily used, the development of technologies in the fields related to mobile devices as described above has been activated. In addition, chargeable/dischargeable secondary batteries are used as a power source for an electric vehicle (EV), a hybrid electric vehicle (HEV), a plug-in hybrid electric vehicle (P-HEV) and the like, in an attempt to solve air pollution and the like caused by existing gasoline vehicles using fossil fuel. Therefore, there is a growing need for development of the secondary battery.

Currently commercialized secondary batteries include a nickel cadmium battery, a nickel hydrogen battery, a nickel zinc battery, a lithium secondary battery, and the like. Among them, the lithium secondary battery has come into the spotlight because they have advantages, for example, hardly exhibiting memory effects compared to nickel-based secondary batteries and thus being freely charged and discharged, and having very low self-discharge rate and high energy density.

Such lithium secondary battery mainly uses a lithium-based oxide and a carbonaceous material as a cathode active material and an anode active material, respectively. The lithium secondary battery includes an electrode assembly in which a cathode plate and an anode plate each coated with the cathode active material and the anode active material are disposed with a separator being interposed between them, and a battery case that seals and houses the electrode assembly together with an electrolyte solution.

Generally, the lithium secondary battery may be classified based on the shape of the exterior material into a can type secondary battery in which the electrode assembly is built in a metal can, and a pouch type secondary battery in which the electrode assembly is built in a pouch made of an aluminum laminate sheet.

In the case of a secondary battery used for small-sized devices, two to three battery cells are disposed, but in the case of a secondary battery used for a middle or large-sized device such as an automobile, a battery module in which a large number of battery cells are electrically connected is used. In such a battery module, a large number of battery cells are connected to each other in series or in parallel to form a cell stack, thereby improving capacity and output. In addition, one or more battery modules may be mounted together with various control and protection systems such as BMS (battery management system) and a cooling system to form a battery pack.

<FIG> is a perspective view showing a conventional battery module, <FIG> is a cross-sectional view taken along the cutting line A-A' of <FIG>, and <FIG> is a perspective view showing an end plate included in the battery module of <FIG>. Particularly, <FIG> shows the surface of the end plate facing the battery cell.

Referring to <FIG>, a conventional battery module <NUM> can be manufactured by housing a plurality of battery cells <NUM> in a module frame <NUM>, and then joining an end plate <NUM> to the module frame <NUM>. When the battery modules <NUM> are gathered by a plurality of numbers to form a battery pack, or when the battery modules are mounted on a vehicle or the like, each battery module <NUM> can be fixed to a structure such as a pack frame (not shown). At this time, the conventional battery module <NUM> may be fixed by forming a mounting structure at four corners. Specifically, mounting holes <NUM> into which bolts 40B can be inserted can be formed at both ends of the end plate <NUM> of the battery module <NUM>. The bolt 40B is inserted in the downward direction into the mounting hole <NUM>, and the nut 40N is coupled to the end of the bolt 40B, so that the battery module <NUM> can be fixed to the pack frame or the like.

However, in the case of the conventional battery module <NUM>, since the bolt 40B has a form of being inserted downward, the mounting hole <NUM> has a form that extends along a height direction (a direction parallel to the z-axis) as shown in the figure. Therefore, referring to <FIG> and <FIG>, waste of the space occurs as much as the space in which the mounting hole <NUM> is formed between the end plate <NUM> and the battery cells <NUM>. That is, in order to fix the battery module <NUM>, mounting holes <NUM> that extend along the height direction were formed at both ends of the end plate <NUM>, but this caused the deterioration of the space utilization of the battery module <NUM>.

Increasing the space utilization of the battery module is directly linked to the performance of the battery pack, such as increasing the energy density of the battery module and the battery pack including the same, or enabling downsizing of the battery pack, there is a need to improve the space utilization of the battery module.

Further prior art is described in <CIT>, <CIT>, and <CIT>.

It is an object of the present disclosure to provide a battery pack with at least one battery module capable of providing additional space inside while forming a mounting structure.

However, the problem to be solved by embodiments of the present disclosure is not limited to the above-described problems, and can be variously expanded within the scope of the technical idea included in the present disclosure.

This object is accomplished with a battery pack comprising the features of patent claim <NUM>.

Dependent claims are directed on features of preferred embodiments of the present disclosure.

According to embodiments of the present disclosure, a mounting hole is provided at the lower side of the battery module, and the height of the mounting part is adjusted, thereby capable of forming a mounting structure and at the same time, providing an additional space therein and increasing space utilization.

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 may 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 the upper end of the reference portion toward the opposite direction of gravity.

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

Further, throughout the description, 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.

<FIG> is a perspective view showing a battery module used in a battery pack according to an embodiment of the present disclosure. <FIG> is an exploded perspective view of the battery module of <FIG>. <FIG> is a perspective view of a battery cell included in the battery module of <FIG>.

Referring to <FIG>, a battery module <NUM> according to one embodiment of the present disclosure includes a battery cell stack <NUM> in which a plurality of battery cells <NUM> are stacked, a module frame <NUM> that houses the battery cell stack <NUM> is open on two opposing surfaces, and end plates <NUM> cover the open surfaces of the module frame <NUM>.

First, the battery cell <NUM> is preferably a pouch-type battery cell, and may be formed in a rectangular sheet-like structure. For example, the battery cell <NUM> according to the present embodiment has a structure in which the two electrode leads <NUM> and <NUM> face each other and protrude from one end and the other end, respectively.

Particularly, referring to <FIG>, the battery cell <NUM> according to the present embodiment has a structure in which the two electrode leads <NUM> and <NUM> face each other and protrude from one end 114a and the other end 114b, respectively. More specifically, the electrode leads <NUM> and <NUM> are connected to an electrode assembly (not shown) and are protruded from the electrode assembly (not shown) to the outside of the battery cell <NUM>.

Meanwhile, the battery cell <NUM> can be manufactured by joining both ends 114a and 114b of a cell case <NUM> and one side portion 114c connecting them in a state in which an electrode assembly (not shown) is housed in a cell case <NUM>. In other words, the battery cells <NUM> according to the present embodiment have a total of three sealing portions 114sa, 114sb and 114sc, the sealing portions 114sa, 114sb and 114sc have a structure that is sealed by a method such as heat-sealing, and the remaining other one side portion can be composed of a connection part <NUM>. The cell case <NUM> can be composed of a laminated sheet including a resin layer and a metal layer.

Further, the connection portion <NUM> may extend long along one edge of the battery cell <NUM>, and a protrusion portion 110p of the battery cell <NUM> called a bat-ear may be formed at an end portion of the connection part <NUM>. However, the protrusion portion 110p is an exemplary structure, and the battery cell <NUM> according to another embodiment of the present disclosure may have a form in which a protrusion portion is not formed and the connection portion <NUM> extends in a straight line.

A plurality of battery cells <NUM> are stacked so as to be electrically connected to each other, thereby forming a battery cell stack <NUM>. Particularly, as shown in <FIG>, the plurality of battery cells <NUM> can be stacked along the y-axis direction. Thereby, one electrode lead <NUM> of the battery cells <NUM> may be protruded toward the x-axis direction, and the other electrode lead <NUM> may protrude toward the -x-axis direction.

The module frame <NUM> is open at one surface and at another surface facing the one surface. More specifically, the module frame <NUM> is opened in both directions in which the electrode leads <NUM> and <NUM> protrude with respect to the battery cell stack <NUM>. The end plates <NUM> cover the open surfaces of the module frame <NUM>, respectively. The battery cell stack <NUM> is housed in the module frame <NUM> and the end plates <NUM> being thereby capable of physically protecting the battery cell stack <NUM>. For this purpose, the module frame <NUM> and the end plates <NUM> may include a metal material having a predetermined strength. Meanwhile, the module frame <NUM> and the end plates <NUM> may be joined by a method such as welding in a state in which corresponding corner portions are in contact with each other.

Meanwhile, the battery module <NUM> according to the present embodiment further includes a busbar frame <NUM> on which a busbar <NUM> and a terminal busbar <NUM> are mounted.

The busbar <NUM> and the terminal busbar <NUM> can be joined to the electrode leads <NUM> and <NUM> of the battery cells <NUM> in order to electrically connect the plurality of battery cells <NUM>. Specifically, the busbar frame <NUM> on which the busbar <NUM> and the terminal busbar <NUM> are mounted can be disposed on the one surface (x-axis direction) and the other surface (-x-axis direction) of the battery cell stack <NUM>. The one surface (x-axis direction) and the other surface (-x-axis direction) of the battery cell stack <NUM> correspond to the surfaces in the direction in which the electrode leads <NUM> and <NUM> of the battery cells <NUM> protrude. In other words, the busbar frame <NUM> are located between the battery cell stack <NUM> and the end plates <NUM>.

A lead slit may be formed at the busbar frame <NUM>, and the electrode leads <NUM> and <NUM> can be bent after passing through the lead slit, and joined to the busbar <NUM> or the terminal busbar <NUM>. As long as physical and electrical connection is possible, the joining method is not particularly limited, and weld-joining can be performed as an example.

Meanwhile, a slit may be formed in the busbar <NUM> or the terminal busbar <NUM>, and the slit may be located so as to correspond to the lead slit of the busbar frame <NUM>. The electrode leads <NUM> and <NUM> that have passed through the lead slit may be bent by passing through the slit of the busbar <NUM> or the slit of the terminal bus bar <NUM>.

Meanwhile, a part of the terminal busbar <NUM> may be exposed to the outside of the battery module <NUM>. Specifically, an opening is formed in the end plate <NUM> or an insulating cover (not shown), and a part of the terminal busbar <NUM> may be exposed as shown in <FIG>. A part of the exposed terminal busbar <NUM> can be connected to another battery module or a BDU (battery disconnect unit) or the like to realize a high voltage (HV) connection. Here, the HV connection is a connection that plays a role of a power source for supplying electric power, and refers to a connection between battery cells or a connection between battery modules.

Next, an end plate, a mounting portion, and a mounting hole according to an embodiment of the present disclosure will be described in detail with reference to <FIG> and <FIG>.

<FIG> is a partial perspective view showing a state in which the lower surface of the battery module of <FIG> is inverted so as to face upward. <FIG> is a perspective view of an end plate included in the battery module of <FIG>. Particularly, <FIG> shows a surface of the end plate facing the battery cell stack.

Referring to <FIG>, <FIG> and <FIG>, the end plate <NUM> according to the present embodiment includes a mounting portion <NUM> in which a mounting hole <NUM> is formed. The mounting hole <NUM> is opened at the lower surface of the end plate <NUM>, and a thread is formed on the inner surface of the mounting hole <NUM>.

More specifically, the end plate <NUM> according to the present embodiment includes a body portion <NUM>, first and second side portions <NUM> and <NUM>, an upper side portion <NUM>, and a lower side portion <NUM>. The body portion <NUM> is a portion facing the battery cell stack <NUM>, and the first and second side portions <NUM> and <NUM>, the upper side portion <NUM>, and the lower side portion <NUM> are portions that are extended in a direction perpendicular to one surface of the body portion <NUM> from both sides, an upper side, and a lower side of the body portion <NUM>. That is, the end plate <NUM> according to the present embodiment has a cover shape that is opened in one surface facing the battery cell stack <NUM>.

At this time, the mounting hole <NUM> according to the present embodiment is opened on the lower surface of the lower portion <NUM> of the end plate <NUM>, and the mounting portion <NUM> may extend along a direction parallel to one surface of the body portion <NUM>. Thereby, in the mounting structure for fixing the battery module <NUM> to the pack frame, etc., the bolt inserted into the mounting hole <NUM> is coupled upwardly to the mounting hole <NUM>.

Meanwhile, referring to <FIG>, the height h2 of the mounting portion <NUM> in which the mounting hole is formed may be <NUM> times or less the height h1 of the end plate <NUM>. In another example, the height h2 of the mounting portion <NUM> may be <NUM> times or less, more preferably <NUM> times or less the height h1 of the end plate <NUM>. That is, since the mounting hole <NUM> according to the present embodiment is opened on the lower surface of the lower portion <NUM> of the end plate <NUM>, the height of the mounting part <NUM> does not need to be formed in the same manner as the height of the end plate <NUM>, unlike the conventional end plate <NUM> shown in <FIG>. Even if the height h2 of the mounting portion <NUM> is formed to be low by <NUM> times or less the height h1 of the end plate <NUM>, the battery module <NUM> can be sufficiently fixed. Therefore, an empty space can be provided in the upper portion of the mounting portion <NUM> between the end plate <NUM> and the battery cell stack <NUM>. The lower limit of the height is not particularly limited, but the height h2 of the mounting portion <NUM> may be <NUM> times or more the height h1 of the end plate <NUM> in order to have the minimum degree of fastening. The conventional battery module <NUM> has a mounting hole <NUM> structure that is long in the height direction, and needs to secure a space for mounting and fastening, whereas the battery module <NUM> according to the present embodiment can implement a mounting hole <NUM> structure that is short in the height direction, and thus can secure an additional space within the battery module <NUM>. It is possible to utilize the space, such as configuring the conventional wasted space to increase the battery capacity. Because of this advantage in terms of space utilization, the battery module and the battery pack including the same according to the present embodiment can have advantages in terms of energy density or downsizing.

Next, a battery pack according to an embodiment of the present disclosure will be described in detail with reference to <FIG> and <FIG>.

<FIG> is a partial perspective view of a battery module and a pack frame according to an embodiment of the present disclosure. <FIG> is a schematic diagram showing a state in which a battery module according to an embodiment of the present disclosure is mounted on a pack frame.

Referring to <FIG>, <FIG> and <FIG>, the battery pack <NUM> according to an embodiment of the present disclosure includes a battery module <NUM>, a pack frame <NUM> that houses the battery module <NUM>, and a bolt <NUM> that passes through the through hole <NUM> formed in the bottom portion <NUM> of the pack frame <NUM> to be coupled to the mounting hole <NUM>.

The battery modules <NUM> may be gathered by a plurality of numbers to form a battery pack <NUM>, wherein each battery module <NUM> may be fixed to a structure such as the pack frame <NUM>. At this time, a through hole <NUM> is formed in the bottom portion <NUM> of the pack frame <NUM>, and the bolt <NUM> passes upwardly through the through hole <NUM>, and then can be fastened to the mounting hole <NUM> of the battery module <NUM>.

More specifically, the bottom portion <NUM> of the pack frame <NUM> according to the present embodiment may include a mounting plate <NUM> for supporting the battery module <NUM>, and a lower plate <NUM> located under mounting plate <NUM>.

By forming the above-mentioned through hole <NUM> in the mounting plate <NUM>, it is possible to support the battery module <NUM> and at the same time, fix the battery module <NUM> to the mounting plate <NUM>, thereby forming a mounting structure. That is, the mounting hole <NUM> of the battery module <NUM> and the bolt <NUM> may be coupled with the mounting plate <NUM> being interposed therebetween.

Meanwhile, the lower plate <NUM> is located under the mounting plate <NUM>, and although not specifically shown in the figure, an equipment such as a cooling water supply pipe for supplying cooling the battery module <NUM> may be provided between the mounting plate <NUM> and the lower plate <NUM>.

Meanwhile, referring to <FIG>, in the lower plate <NUM> according to the present embodiment, an opening 1112P may be formed in a portion corresponding to the through hole <NUM> formed in the mounting plate <NUM>. That is, an opening 1112P may be formed in each of the portions corresponding to the through hole <NUM> with reference to the Z-axis direction. As described above, the bolt <NUM> according to the present embodiment is coupled upwardly to the mounting hole <NUM> of the battery module <NUM>, but a space is needed for mounting the equipment for assembling the bolt <NUM>. Therefore, by forming the opening 1112P in the lower plate <NUM>, a space for assembling the bolt <NUM> is provided.

Meanwhile, the pack frame <NUM> further includes a side surface portion <NUM> located on side surface of the battery module <NUM> and bottom portion <NUM>. The side surface portion <NUM> can form a stepped structure and come into contact with each of the mounting plate <NUM> and the lower plate <NUM>. At this time, a sealing member <NUM> having adhesive properties may be located between the side surface portion <NUM> and the mounting plate <NUM>. That is, the side surface portion <NUM> and the mounting plate <NUM> are adhered and fixed, and at the same time, a gap therebetween can be sealed by the sealing member <NUM>. As the sealing member <NUM> according to the present embodiment is located between the side surface portion <NUM> and the mounting plate <NUM>, the space between the side surface portion <NUM> and the mounting plate <NUM> is sealed even if the opening 1112P is formed, whereby it is possible to prevent water or the like from flowing into the pack frame <NUM>.

Meanwhile, if the side surface portion <NUM> and the mounting plate <NUM> have adhesive properties so that they can be adhered, fixed, and sealed, the material of the sealing member <NUM> is not particularly limited. As described above, a space for assembling the bolt <NUM> must be secured, such as an opening 1112P being formed in the lower plate <NUM>, and it is necessary to seal between the mounting plate <NUM> and the side surface portion <NUM> to prevent the inflow of water. Thus, it is preferable that the sealing member <NUM> is located between the side surface portion <NUM> and the mounting plate <NUM> to be adhered and sealed.

<FIG> is a schematic diagram showing a state in which a battery module according to a modified embodiment of the present disclosure is mounted on a pack frame. Parts overlapping with the above-mentioned contents are omitted in order to avoid repetition of the description.

Referring to <FIG>, the bottom portion <NUM> of the pack frame <NUM> according to the modified embodiment of the present disclosure may include a mounting plate <NUM> for supporting the battery module <NUM> and a lower plate <NUM>' located under mounting plate <NUM>. The pack frame <NUM> may further include a side surface portion <NUM> located on the side surface of the battery module <NUM>.

At this time, the lower plate <NUM>' according to the present embodiment can be formed with a lower through hole <NUM> rather than an opening, and the lower through hole <NUM> of the lower plate <NUM>' may be located so as to correspond to the through hole <NUM> of the mounting plate <NUM> with reference to the Z-axis direction. Further, the bolt <NUM>' according to the present embodiment is formed longer than the bolt <NUM> described in <FIG>, and after sequentially passing through the lower through hole <NUM> of the lower plate <NUM>' and the through hole <NUM> of the mounting plate <NUM>, it can be coupled to the mounting hole <NUM> of the battery module <NUM>.

At this time, the adhesive sealing member <NUM>' according to the present embodiment may be located between the side surface portion <NUM> and the lower plate <NUM>'. Since the lower through hole <NUM> of the lower plate <NUM>' is naturally sealed by the insertion of the bolt <NUM>' according to the present embodiment, a sealing member <NUM>' for preventing water from entering the pack frame <NUM> can be located between the side surface portion <NUM> and the lower plate <NUM>'. That is, the sealing member <NUM>' according to the present embodiment can play a function of preventing water inflow while being located between the side surface portion <NUM> and the lower plate <NUM>'. Meanwhile, if necessary, a ring-shaped stopper for sealing may be disposed between the head of the bolt <NUM>' and the lower plate <NUM>' according to the present embodiment.

The terms representing directions such as the front side, the rear side, the left side, the right side, the upper side, and the lower side have been used in embodiments of the present disclosure, but the terms used are provided simply for convenience of description and may become different according to the position of an object, the position of an observer, or the like.

The one or more battery modules according to embodiments of the present disclosure described above can be mounted together with various control and protection systems such as a battery management system (BMS) and a cooling system to form a battery pack.

Claim 1:
A battery pack (<NUM>) with a battery module (<NUM>) comprising:
a battery cell stack (<NUM>) in which a plurality of battery cells (<NUM>) are stacked;
a module frame (<NUM>) that houses the battery cell stack (<NUM>) and is opened in its one surface; and
end plates (<NUM>) that cover the open surfaces of the module frame (<NUM>),
wherein the end plates (<NUM>) comprise a mounting portion (<NUM>) having a mounting hole (<NUM>) formed therein, and
wherein the mounting hole (<NUM>) is opened at a lower surface of the end plate (<NUM>), and a thread is formed on an inside surface of the mounting hole (<NUM>),
a pack frame (<NUM>) that houses the battery module (<NUM>); and
a bolt (<NUM>) that passes through a through hole (<NUM>) formed at the bottom portion of the pack frame (<NUM>) and is coupled to the mounting hole (<NUM>),
characterized in that
the bottom portion of the pack frame (<NUM>) comprises a mounting plate (<NUM>) for supporting the battery module (<NUM>) and a lower plate (<NUM>) located under the mounting plate (<NUM>), and
the through hole (<NUM>) is formed in the mounting plate (<NUM>), and the bolt (<NUM>) passes through the through hole (<NUM>) of the mounting plate (<NUM>) to be coupled to the mounting hole (<NUM>).