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 an enhanced safety, and a battery pack including the same.

With the increase of the technological development and demand for a mobile device, demand for a secondary battery as an energy source is rapidly increasing, and accordingly, many researches of the battery capable of meeting a variety of needs are emerging.

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, and a laptop computer.

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/parallel.

Meanwhile, when a plurality of battery cells are connected in series/parallel to configure a battery pack, a method of 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. Since the battery cells constituting these middle or large-sized battery modules are composed of chargeable/dischargeable secondary batteries, such a high-output and large-capacity secondary battery generates a large amount of heat in a charging and discharging process.

The battery module may include a battery cell stack in which a plurality of battery cells are stacked, a frame for housing the battery cell stack, and end plates for covering the front and rear surfaces of the battery cell stack.

<FIG> is a view showing the appearance of a battery module mounted on a conventional battery pack at the time of ignition. <FIG> is a section taken the line A-A of <FIG>, which is a cross-sectional view showing the appearance of a flame that affects adjacent battery modules during ignition of a battery module mounted on a conventional battery pack.

Referring to <FIG>, the conventional battery module includes a battery cell stack in which a plurality of battery cells <NUM> are stacked, a frame <NUM> for housing the battery cell stack, end plates <NUM> formed on the front and rear surfaces of the battery cell stack, terminal busbars <NUM> formed so as to protrude to the outside of the end plates <NUM>, and the like.

The frame <NUM> and the end plate <NUM> can be combined so as to be sealed by welding. When the frame <NUM> for housing the battery cell stack and the end plate <NUM> are combined in this way, the internal pressure of the battery cells <NUM> increases during overcharge of the battery module to exceed a limit value of the fusion strength of the battery cell. In this case, high-temperature heat, gas, and flame generated in the battery cells <NUM> can be discharged to the outside of the battery cell <NUM>.

At this time, the high-temperature heat, gas and flame may be discharged through the openings formed in the end plates <NUM>. However, in a battery pack structure in which a plurality of battery modules are arranged so that the end plates <NUM> face each other, the high-temperature heat, gas and flame ejected from the battery module may affect a battery module. Thereby, the terminal busbar <NUM> formed on the adjacent end plates <NUM> of the battery module may be damaged, and high-temperature heat, gas, and flame may enter the inside of the battery module via the openings formed in the adjacent end plates <NUM> of the battery module to damage the plurality of battery cells <NUM>.

Document <CIT> discloses a battery module having a case frame including a channel to prevent a generated flame from being exposed to the outside.

It is an object of the present disclosure to provide a battery module capable of dispersing high-temperature heat and flame discharged when an ignition phenomenon occurs inside the battery module, and a battery pack including the same.

However, the technical 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.

According to one embodiment of the present disclosure, there is provided a battery module as defined in the appended claims.

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

According to embodiments of the present disclosure, in order to control high temperature heat, gas and flame when thermal runaway phenomenon occurs in the battery module, a venting part can be formed at the upper end of the battery module so that it is adjacent to the module connector disposed on the other side of the battery module rather than the terminal busbar disposed on one side of the battery module, thereby delaying the propagation of flames to the adjacent battery module.

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 implement them. The present disclosure can be modified in various different ways, and is not limited to the embodiments set forth herein.

Portions that are irrelevant to the description will be omitted to clearly describe the present disclosure, and like reference numerals designate like elements throughout the specification.

Further, in the figures, the size and thickness of each element are arbitrarily illustrated for convenience of description, and the present disclosure is not necessarily limited to those illustrated in the figures. In the figures, the thickness of layers, regions, etc. are exaggerated for clarity. In the figures, for convenience of description, the thicknesses of some layers and regions are shown to be exaggerated.

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 specification, 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 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.

<FIG> is a perspective view showing a battery module according to one 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 100a according to one embodiment of the present invention includes a battery cell stack <NUM> in which a plurality of battery cells <NUM> including electrode leads <NUM> and <NUM> protruding in the mutually opposing directions are stacked, a module frame <NUM> for housing the battery cell stack <NUM>, a first busbar frame <NUM> disposed on one surface of the battery cell stack <NUM> in one direction (x-axis direction) in which the electrode leads <NUM> protrude, and a second busbar frame <NUM> disposed on the other surface of the battery cell stack <NUM> in the other direction (-x-axis direction) in which the electrode lead <NUM> protrudes.

First, referring to <FIG>, the battery cell <NUM> is preferably a pouch-type battery cell. For example, the battery cell <NUM> according to the present embodiment has a structure in which two electrode leads <NUM> and <NUM> face each other and protrude from one end 114a and the other end 114b of the cell main body <NUM>, respectively. More specifically, the electrode leads <NUM> and <NUM> are connected to an electrode assembly (not shown), and protrude from the electrode assembly (not shown) to the outside of the battery cell <NUM>.

On the other hand, the battery cell <NUM> can be manufactured by joining both end parts 114a and 114b of the cell case <NUM> and one side part 114c connecting them, in a state in which the electrode assembly (not shown) is housed in a 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, the sealing parts 114sa, 114sb and 114sc have a structure sealed by a method such as heat fusion, and the remaining other side part may be formed of a connection part <NUM>. The cell case <NUM> may be formed of a laminated sheet containing a resin layer and a metal layer.

In addition, the connection part <NUM> may extend long along one edge of the battery cell <NUM>, and a protrusion part 110p of the battery cell <NUM> called a bat-ear may be formed at an end part of the connection part <NUM>. Further, while the cell case <NUM> is sealed with the protruding electrode leads <NUM> and <NUM> being interposed therebetween, a terrace part <NUM> may be formed between the electrode leads <NUM> and <NUM> and the cell main body <NUM>. That is, the battery cell <NUM> includes a terrace part <NUM> formed to extend from the cell case <NUM> in a protruding direction of the electrode leads <NUM> and <NUM>.

The battery cell <NUM> may be configured by a plurality of numbers, and the plurality of battery cells <NUM> may be stacked so as to be electrically connected to each other, thereby forming a battery cell stack <NUM>. Referring to <FIG>, the battery cells <NUM> can be stacked along the y-axis direction to form a battery cell stack <NUM>. A first busbar frame <NUM> may be located on one surface of the battery cell stack <NUM> in the protruding direction of the electrode leads <NUM> (x-axis direction). A second busbar frame <NUM> may be located on the other surface of the battery cell stack <NUM> in the protruding direction of the electrode leads <NUM> (-x-axis direction). The battery cell stack <NUM>, the first busbar frame <NUM>, or the second busbar frame <NUM> may be housed in the module frame <NUM>. The module frame <NUM> can protect the battery cell stack <NUM> housed inside the module frame <NUM> and the electrical components connected thereto from external physical impacts.

The module frame <NUM> according to the present disclosure is a structure in which a U-shaped frame and an upper plate are combined. In the case of a structure in which a U-shaped frame and an upper plate are combined, it can be formed by combining the upper plate to the upper side of a U-shaped frame, which is a metal plate material having a lower surface and both sides combined or integrated, and it may be manufactured by press molding.

A thermal conductive resin can be injected between the battery cell stack <NUM> and the lower surface of the module frame <NUM>, and a thermal conductive resin layer (not shown) may be formed between the battery cell stack <NUM> and the lower surface of the module frame <NUM> through the injected thermal conductive resin.

On the other hand, the module frame <NUM> can be opened in the protruding direction of the electrode leads <NUM> and <NUM> (x-axis direction, -x-axis direction), and a first end plate <NUM> and a second end plate <NUM> may be located on both open sides of the module frame <NUM>, respectively. The first end plate <NUM> can be joined to the module frame <NUM> while covering the first busbar frame <NUM>, and the second end plate <NUM> can be joined to the module frame <NUM> while covering the second busbar frame <NUM>. That is, a first busbar frame <NUM> may be located between the first end plate <NUM> and the battery cell stack <NUM>, and a second busbar frame <NUM> may be located between the second end plate <NUM> and the battery cell stack <NUM>. Further, an insulating cover <NUM> (see <FIG> ) for electrical insulation may be located between the first end plate <NUM> and the first busbar frame <NUM>.

The first end plate <NUM> and the second end plate <NUM> are located so as to cover the one surface and the other surface of the battery cell stack <NUM>, respectively. The first end plate <NUM> and the second end plate <NUM> can protect the first busbar frame <NUM>, the second busbar frame <NUM> and various electrical components connected thereto from external impacts. For this purpose, it must have a predetermined strength and may include a metal such as aluminum. Further, the first end plate <NUM> and the second end plate <NUM> may be joined to a corresponding edge of the module frame <NUM> by a method such as welding, respectively.

The first busbar frame <NUM> is located on one surface of the battery cell stack <NUM> to cover the battery cell stack <NUM> and at the same time, guide the connection between the battery cell stack <NUM> and an external device. Specifically, at least one of the busbar, the terminal busbar and the module connector may be mounted on the first busbar frame <NUM>. In particular, at least one of the busbar, the terminal busbar and the module connector may be mounted on a surface opposite to the surface where the first busbar frame <NUM> faces the battery cell stack <NUM>. In one example, <FIG> shows a state in which the busbar <NUM> and the terminal busbar <NUM> are mounted on the first busbar frame <NUM>.

The battery cells <NUM> constituting the battery cell stack <NUM> may be connected in series or in parallel by the busbar <NUM> or the terminal busbar <NUM>, and the battery cells <NUM> can be electrically connected to an external device or circuit through the terminal busbar <NUM> exposed to the outside of the battery module 100a. In one example, the terminal busbar <NUM> may be connected to an external busbar that provides a connection with other battery modules adjacent to the battery module including the terminal busbar <NUM>.

The first busbar frame <NUM> may include an electrically insulating material. The first busbar frame <NUM> restricts the busbar <NUM> or the terminal busbar <NUM> from making contact with the battery cells <NUM>, except for the portion where the busbar <NUM> or the terminal busbar <NUM> is joined to the electrode leads <NUM>, thereby preventing the occurrence of a short circuit.

On the other hand, as described above, the second busbar frame <NUM> may be located on the other surface of the battery cell stack <NUM>. A busbar and a module connector may be mounted on the second busbar frame <NUM>. The electrode lead <NUM> may be joined to the busbar mounted on the second busbar frame <NUM>. The second busbar frame <NUM> may include an electrically insulating material to prevent a short circuit.

An opening in which the terminal busbar <NUM> is exposed can be formed in the first end plate <NUM> according to the present embodiment. The opening may be a terminal busbar opening. In one example, as shown in <FIG> and <FIG>, a terminal busbar opening <NUM> to which the terminal busbar <NUM> is exposed can be formed in the first end plate <NUM>. The terminal busbar <NUM> further includes an upwardly protruding portion as compared with the busbar <NUM>. Such upwardly protruding portion is exposed to the outside of the battery module 100a through the terminal busbar opening <NUM>. The terminal busbar <NUM> exposed via the terminal busbar opening <NUM> may be connected to another battery module or a battery disconnect unit (BDU) to form a high voltage (HV) connection.

<FIG> is a perspective view showing the second end plate of the battery module of <FIG> by changing a viewing angle so that it can be seen from the front. <FIG> is a cross-sectional view taken along the cutting line B-B of <FIG>.

Referring to <FIG>, an opening through which at least one of the module connectors is exposed may be formed in the second end plate <NUM> according to the present embodiment. The opening may be a module connector opening. In one example, as shown in <FIG>, a module connector opening <NUM> through which the module connector <NUM> is exposed may be formed in the second end plate <NUM>. This means that the module connector <NUM> is mounted on the above-mentioned second busbar frame <NUM>.

Meanwhile, although not specifically illustrated in the figure, the module connector <NUM> may be connected to a temperature sensor, a voltage measuring member, or the like provided inside the battery module 100a. This module connector <NUM> is connected to an external BMS (Battery Management System) to form an LV (Low voltage) connection. The temperature sensor or the voltage measuring member perform the function of transmitting temperature information, voltage level and the like measured by the temperature sensor or the voltage measuring member to the external BMS.

Referring to <FIG>, <FIG> and <FIG>, a venting part <NUM> is formed on the upper plate of the module frame <NUM>, wherein the venting part <NUM> may be formed adjacent to the module connector <NUM> rather than the terminal busbar <NUM>. The venting part <NUM> has a hole structure formed in the upper plate of the module frame <NUM>. The hole structure may penetrate the upper plate of the module frame <NUM> obliquely in a direction close to the second busbar frame <NUM>. The venting part <NUM> may be formed so as to vent gas in a direction in which the second busbar frame <NUM> or the second end plate <NUM> is located. When heat, gas, flame or spark is generated inside the battery module 100a, this is for discharging the heat, gas, flames or spark in a direction toward the second busbar frame <NUM> or the second end plate <NUM> in which a member (hereinafter referred to as an LV member) forming an LV connection such as the module connector <NUM> is located, rather than in the direction toward the first busbar frame <NUM> or the first end plate <NUM> in which a member (hereinafter referred to as an HV member) forming an HV connection such as the terminal busbar <NUM> is located.

According to the present embodiment, as shown in <FIG>, a discharge passage <NUM> may be formed between the upper part of the module frame <NUM> and the battery cell stack <NUM>. Gas or heat generated between the first end plate <NUM> and the battery cell stack <NUM> is disposed on the second busbar frame <NUM> or the second end plate <NUM> located on the opposite side of the first end plate <NUM> through the discharge passage <NUM>. Gas or heat moved toward the second busbar frame <NUM> or the second end plate <NUM> may be discharged from the battery module 100a through the venting part <NUM>. The HV member is more prone to overheating than the LV member and is more susceptible to self-ignition or internal ignition. Thus, if the gas or heat generated around the first end plate <NUM> through the discharge passage <NUM> is induced in the direction in which the second end plate <NUM> is located, an internal heat propagation phenomenon may be alleviated.

Referring to <FIG>, in the case of a conventional battery module, high-temperature heat, gas, flame and the like ejected through an opening of the battery module may affect adjacent battery modules. In particular, adjacent battery modules facing each other for HV connection may cause damage to other electrical components including the terminal busbar <NUM> or the battery cell <NUM>.

Unlike the conventional case, in the battery module 100a according to the present embodiment, the venting part <NUM> is formed on the upper plate of the module frame <NUM>, and the venting part <NUM> is formed adjacent to the module connector <NUM> rather than the terminal busbar <NUM>, thereby capable of restricting the discharge of high-temperature heat, gas, flame and the like resulting from the battery cell <NUM> through the opening of the first end plate <NUM>, for example, the terminal busbar opening <NUM>. When the flame is transferred to the terminal busbar <NUM>, the external busbars connecting the adjacent battery modules may be melted and further ignited due to an internal short circuit, which is highly likely to be transferred to the adjacent battery modules. However, according to the present embodiment, damage to adjacent battery modules and HV connection structures can be greatly reduced.

<FIG> is a perspective view showing a battery module according to another embodiment of the present disclosure.

Referring to <FIG>, the venting part <NUM> according to the present embodiment may be formed so as to be vented in the upward direction with respect to the battery cell stack <NUM>. The venting part <NUM> may include an inflow port <NUM> that is connected to the battery cell stack <NUM> and is formed in an upward direction on the upper surface of the module frame <NUM>, a discharge port <NUM> that is formed in the upward direction and discharges gas flown in through the inflow port <NUM>, and a connection part <NUM> that connects the inflow port <NUM> and the discharge port <NUM>. The connection part <NUM> may be formed in a direction perpendicular to the inflow and discharge directions of the inflow port <NUM> and the discharge port <NUM>.

The venting unit <NUM> can discharge high-temperature heat, gas, and flame inside the battery module toward the upward direction of the battery module, thereby minimizing damage to other battery modules arranged by abutting the end plate. However, since the discharge port <NUM> is formed toward the upward direction, foreign materials in the air can enter the discharge port <NUM> due to gravity. Thus, the connection part <NUM> can be formed in a direction perpendicular to the discharge port <NUM>, thereby minimizing a phenomenon in which foreign materials flown into the discharge port <NUM> are flown into the battery module through the inflow port <NUM>.

Further, a foreign material blocking part (not shown) for blocking foreign substances entering through the discharge port <NUM> is formed on the connection part <NUM>, thereby preventing foreign materials from entering into the portion of the inflow port <NUM> via the connection part <NUM> from the portion of the discharge port <NUM>.

Referring to <FIG>, the venting unit <NUM> according to the present embodiment includes an inflow port <NUM> that is formed on the upper surface of the module frame <NUM> to connect to the battery cell stack, and a discharge port <NUM> that discharges gas flown through the inflow port <NUM>, wherein the discharge port <NUM> may be formed in a direction perpendicular to the inflow port <NUM>. In addition, the venting part <NUM> includes a connection part <NUM> that is formed between the inflow port <NUM> and the discharge port <NUM> and guides gas flowing into the inflow port <NUM> in a direction in which the discharge port <NUM> is located, and the upper surface of the connection part <NUM> may be formed obliquely.

The discharge port <NUM> is formed in a direction perpendicular to the upper surface of the inflow port <NUM> and the module frame <NUM>, thereby capable of preventing the phenomenon that foreign materials floating in the air from enter the discharge port <NUM> due to gravity. In addition, the upper surface of the connection part <NUM> is formed obliquely toward the discharge port <NUM>, and high-temperature heat, gas, and flame flown into the inflow port <NUM> switch directions through the connection part <NUM> and are naturally discharged through the discharge port <NUM>.

Next, the experimental results for confirming the effects of the venting part <NUM> of the present embodiment will be described.

Table <NUM> compares the time required for voltage drop depending on the presence/absence and position of the venting unit <NUM> at the time of ignition inside the battery module.

Referring to Table <NUM>, REFERENCE is a case in which the venting part <NUM> is not formed in the battery module, CASE <NUM> is a case where the venting part <NUM> is formed so as to be adjacent to the LV member as in the embodiment of the present disclosure, CASE <NUM> is a case where the venting part <NUM> is formed entirely on the upper plate of the module frame <NUM>.

In the case of REFERENCE, the initial venting and flame generation time was <NUM> sec, and venting and flame were found slightly later than CASE <NUM> and CASE <NUM>. However, on and after <NUM> sec, the voltage drop progressed rapidly, and the total time required for voltage drop was found to be <NUM> sec. This may be because the battery module of REFERENCE has a sealed structure in which the venting part <NUM> is not formed and thus, the oxygen supply is blocked during internal ignition, and the initial venting and flame generation times are delayed. In addition, after venting and flames are generated, ignition is promoted in accordance with the inflow of external oxygen, and the voltage drop can progress rapidly.

In case of CASE <NUM>, the initial venting and flame generation times was <NUM> sec, and venting and flame were found earlier than the time point in other cases. The voltage drop started from <NUM> sec, and the total time required for voltage drop was found to be <NUM> sec until <NUM> sec when the voltage became <NUM>. In case of CASE <NUM>, it was found that the initial voltage drop proceeded very quickly than in other cases. This may be because sufficient oxygen is supplied through the plurality of venting units <NUM>, so that heat propagation is rapidly spread.

In case of CASE <NUM>, the initial venting and flame generation time was <NUM> sec, and the voltage drop progressed from <NUM> sec to <NUM> sec, and the total time for required for voltage drop was found to be <NUM> sec. CASE <NUM> showed a longer total voltage drop time compared to other cases, and the time required for step-by-step voltage drop was also found to be even and long as compared with other cases. This may be because heat propagation can be delayed by properly discharging heat and gas inside the battery module while excess oxygen is not flown in through the venting part <NUM> as compared with CASE <NUM>. In addition, the venting part <NUM> of CASE <NUM> is located adjacent to the LV member and the flow of the gas lamp is induced in the direction in which the LV member is located, it relieves the temperature around the HV member, which may be in a relatively high temperature state.

On the other hand, in the description of Table <NUM>, the reference numerals shown in <FIG> were added to the venting part, and this is only for convenience of description, and the same effect as the above-described description may be exhibited even in <FIG>, <FIG> or other venting parts.

The battery pack according to another embodiment of the present disclosure may include the above-mentioned battery module, an adjacent battery module adjacent to the battery module, and a pack case for housing the battery module and the adjacent battery module. A first terminal busbar and a second terminal busbar included in each of the battery module and the adjacent battery module may be disposed in a direction facing each other. At this time, a first venting part formed in the battery module and a second venting part formed in the adjacent battery module may each have a hole structure in which they are vented away from each other.

The above-mentioned battery module and the battery pack including the same according to the present disclosure can be applied to various devices. Such a device can be applied to a vehicle means such as an electric bicycle, an electric vehicle, or a hybrid vehicle, but the present disclosure is not limited thereto, and is applicable to various devices that can use a secondary battery.

Claim 1:
A battery module (100a) comprising:
a battery cell stack (<NUM>) in which a plurality of battery cells (<NUM>) are stacked,
a module frame (<NUM>) having a structure in which a U-shaped frame and an upper plate are combined, the module frame (<NUM>) housing the battery cell stack (<NUM>),
a first busbar frame (<NUM>) that is housed in the module frame (<NUM>) and covers the front surface of the battery cell stack (<NUM>), and
a second busbar frame (<NUM>) that is housed in the module frame (<NUM>) and covers the rear surface of the battery cell stack (<NUM>),
wherein a terminal busbar (<NUM>) is mounted to the first busbar frame (<NUM>), and a module connector is mounted to the second busbar frame (<NUM>), and
wherein the module frame (<NUM>) is formed with a venting part (<NUM>; <NUM>; <NUM>) penetrating the upper plate, and the venting part (<NUM>; <NUM>; <NUM>) is located closer to the module connector than the terminal busbar (<NUM>).