Patent Description:
The present application claims priority to <CIT> and <CIT> in the Republic of Korea.

A lithium ion battery cell experiences a swelling phenomenon since gas is generated therein depending on the use condition and environment. It is known that gas is mainly generated due to a side reaction of an electrolyte injected into the battery cell.

The battery cell where the swelling phenomenon occurs has a deteriorated charge/discharge performance. In addition, if the pressure inside the battery cell exceeds a threshold value, a case of the battery cell is ruptured so that toxic gas is vented to the outside.

The case of the lithium ion battery cell is made of a flexible pouch film, for example. Since the pouch film has weak rigidity, when the pressure inside the battery cell increases above the limit due to the swelling phenomenon, the sealing part with weak bonding force is ruptured so that gas is leaked to the outside.

The application field of the lithium ion battery cell is rapidly increasing not only to mobile devices such as cellular phones, laptop computers, smart phones and smart pads, but also electric-driven vehicles (EVs, HEVs, PHEVs), large-capacity energy storage systems (ESS), or the like.

In particular, a battery module mounted on the electric-driven vehicle includes a plurality of battery cells connected in series and/or in parallel to secure a high energy capacity.

If some battery cells in the battery module cause a swelling phenomenon, the performance of the entire battery module is degraded. In addition, if the swelled battery cells cause venting while the electric-driven vehicle is running, toxic gas is ejected to the outside, and in the worst case, the charging and discharging of the battery cells that cause venting is stopped, which may result in sudden stop of the electric-driven vehicle. In addition, when a plurality of battery cells cause venting, toxic gas may ignite, which may lead to an accident in which the battery module explodes.

Therefore, in a device equipped with a battery module, there is a need for developing a technology capable of easily detecting that the battery cells included in the battery module are swelling.

Document <CIT> provides an example of a battery cell assembly and a battery module for detecting a swelling phenomenon thereof using a movable guide pin.

The present disclosure is designed to solve the problems of the related art, and therefore the present disclosure is directed to providing an apparatus and method capable of easily detecting that battery cells included in a battery module are swelling over the limit.

In one aspect of the present disclosure, there is provided an apparatus for detecting swelling of a battery module defined in the appended claims. A battery management system, an electric driving mechanism, and a method for detecting swelling of a battery module are also defined in the appended claims.

According to the present disclosure, it is possible to easily detect that a swelling phenomenon occurs in the battery cells included in the battery module. In particular, since an excessive swelling phenomenon of the battery cells may be detected without changing the internal structure of the battery module, the stability of the battery module may be improved. In particular, the present disclosure may be usefully utilized when the battery module is mounted to an electric-driven vehicle.

In the embodiments described below, a battery cell refers to a lithium ion battery cell. Here, the lithium ion battery cell refers to a battery in which lithium ions act as working ions during charging and discharging to induce electrochemical reactions at the positive and negative electrodes.

Meanwhile, even if the name of the battery is changed depending on the type of electrolyte or separator used in the lithium ion battery cell, the type of a packaging material used to package the battery, the internal or external structure of the lithium ion battery cell, or the like, any battery using lithium ions as working ions should be interpreted as being included in the category of lithium ion battery cells.

The present disclosure may also be applied to secondary batteries other than lithium ion battery cells. Therefore, even if the working ions are not lithium ions, any secondary battery to which the technical idea of the present disclosure may be applied should be interpreted as being included in the category of the present disclosure regardless of its type.

In addition, it should be noted in advance that the battery cell may refer to one unit cell or a plurality of unit cells connected in parallel.

<FIG> is a block diagram showing an apparatus for detecting swelling of a battery module according to an embodiment of the present disclosure.

Referring to <FIG>, a swelling detection apparatus <NUM> according to an embodiment of the present disclosure includes a battery module housing <NUM> defining a space in which the battery module <NUM> is placed.

The battery module <NUM> includes a plurality of battery cells <NUM> therein. The plurality of battery cells <NUM> may be stacked in a certain direction. Although not shown in the drawing, a cartridge frame, a cooling fin and the like may be interposed between the battery cells <NUM>.

The plurality of battery cells <NUM> may be connected to each other in series and/or in parallel. A connection relationship of a connector component, for example a bus bar, used to electrically connect the plurality of battery cells <NUM> is not related to the technical idea of the present disclosure and thus will not be described in detail here.

Each battery cell <NUM> has a structure in which an electrode assembly and an electrolyte are packaged by a pouch packaging material, but the present disclosure is not limited thereto. Each battery cell <NUM> includes a pair of electrodes exposed to the outside, and the electrodes of neighboring battery cells <NUM> may be connected in series and/or in parallel.

The battery module housing <NUM> has an approximate box shape and defines a square space therein. The battery module <NUM> may be accommodated in the square space. The cross-sectional area of the battery module housing <NUM> is equal to or larger than the cross-sectional area of the battery module <NUM>.

The battery module housing <NUM> may include front, rear, left and right walls and upper and lower walls. The front, rear, left and right walls and the lower wall may be integrated to constitute a lower case 12a, and the upper wall may constitute an upper case 12b. In this case, the upper case 12b may serve as a cover.

The lower case 12a and the upper case 12b may be made of metal or plastic and may be bonded to each other by known methods such as bolt, adhesive, and welding.

Since the lower case 12a has an open upper portion, the battery module <NUM> is placed on a bottom surface of the lower case 12a through the opening of the lower case 12a. In addition, if the upper case 12b is coupled to the lower case 12a, the battery module <NUM> is accommodated in the battery module housing <NUM>.

The swelling detection apparatus <NUM> according to the present disclosure includes a swelling detection panel <NUM> attached to one surface of the battery module <NUM> and having an edge in contact with an inner surface of the battery module housing <NUM>.

Preferably, the swelling detection panel <NUM> may be made of an elastic plastic. It is preferable that the swelling detection panel <NUM> has a thickness of <NUM> to <NUM>.

Preferably, the area of the swelling detection panel <NUM> is substantially the same as the cross section of the inner space in the battery module housing <NUM>. Here, the cross section refers to a section in a direction perpendicular to the ground.

<FIG> is a partially sectioned view, taken along the line I-I' of <FIG>, to illustrate the structures of points A and B of <FIG>.

Referring to <FIG>, the swelling detection apparatus <NUM> according to the present disclosure includes a slant portion <NUM> having a slant surface S, which protrudes from the inner surface of the battery module housing <NUM> and extends from a first location C1 adjacent to the edge of the swelling detection panel <NUM> to a second location C2 while forming a predetermined angle with the inner surface.

Preferably, the slant portion <NUM> may protrude at a plurality of points (see A and B of <FIG>) along the edge of the swelling detection panel <NUM>.

Even though the drawings show that the slant portion <NUM> protrudes at two points A (<FIG>) on a lower inner surface of the upper case 12b of the battery module housing <NUM> and protrudes at two points B (<FIG>) of a lower inner surface of the lower case 12a, the present disclosure is not limited thereto.

Preferably, the section of the slant portion <NUM> has a right-angled triangular shape, and the slant surface S of the slant portion <NUM> faces a right-angled corner of the right-angled triangle.

Preferably, the length of the slant portion <NUM> may be adjusted in advance according to the degree of swelling to be detected. The length of the slant portion <NUM> and the sensitivity of swelling detection are inversely proportional to each other. That is, as the sensitivity of swelling detection is higher, the length of the slant portion <NUM> becomes shorter.

The swelling detection apparatus <NUM> according to an embodiment of the present disclosure includes a contact sensor unit <NUM> installed at the inner surface of the battery module housing <NUM> immediately adjacent to an end of the slant surface S corresponding to the second location C2 of the slant portion <NUM>.

Preferably, the contact sensor unit <NUM> may be a piezoelectric sensor. The piezoelectric sensor refers to a sensor that outputs a voltage signal corresponding to the magnitude of a pressure when a specific object comes into contact to apply the pressure. Since the piezoelectric sensor is widely known in the art, it will not be described in detail here.

Alternatively, the contact sensor unit <NUM> may be a button switch. The button switch refers to a switch that mechanically contacts a contact point of a switch or release the contact by the push/pull operation of the button.

The button switch includes a spring for elastically biasing the button and two contact points whose electrical connection is selectively controlled by the push/pull operation of the elastically biased button.

The button switch is a well-known electrical component widely known in the art and thus will not be described in detail here.

Preferably, one contact point of the button switch is connected to a DC power supply and the other contact point is connected to the control unit <NUM> via a conductive wire. Therefore, if the button switch is pushed, the two contacts may be connected to each other so that the voltage of the DC power supply is applied to the control unit <NUM>.

Referring to <FIG>, the swelling detection apparatus <NUM> according to the present disclosure may include an alarm unit <NUM> that visually or audibly outputs an alarm message.

The alarm unit <NUM> may be a display or a speaker. The display outputs an alarm message in the form of text or graphic, and the speaker outputs an alarm message in the form of voice or alarm sound. The display may be a liquid crystal display, an organic light emitting diode display, or the like, but the present disclosure is not limited thereto.

The swelling detection apparatus <NUM> according to the present disclosure includes a control unit <NUM> operably coupled to the contact sensor unit <NUM> and the alarm unit <NUM>.

The contact sensor unit <NUM> may output a swelling detection signal when the swelling detection panel <NUM> moves along the slant surface S of the slant portion <NUM> and then is deviated from the second location C2 so that the edge of the swelling detection panel <NUM> contacts the contact sensor unit <NUM>.

If a swelling phenomenon occurs in some or all of the plurality of battery cells <NUM> included in the battery module <NUM> so that the outer wall (especially, the left or right wall) of the battery module <NUM> is inflated, the swelling detection panel <NUM> may move along the slant surface S of the slant portion <NUM> due to the pressure applied by the battery module <NUM>.

<FIG> is a sectional view showing a battery module having no battery cell in which the swelling phenomenon occurs, and <FIG> is a sectional view showing a battery module including a battery cell in which the swelling phenomenon occurs.

As shown in <FIG> and <FIG>, if a swelling phenomenon occurs in some battery cells included in the battery module <NUM>, the inflated battery cell presses the remaining cells to the left and right. In addition, the pressing force reaches an outermost end plate EP that is a component of the case of battery module <NUM>. Since the end plate EP is made of a thin metal or plastic plate, the end plate EP is deformed into a curved surface when a pressure is applied thereto. As a result, the battery module <NUM> presses the swelling detection panel <NUM> toward the slant portion <NUM>, and the pressed swelling detection panel <NUM> moves along the slant surface S.

<FIG> is a diagram showing that the swelling detection panel <NUM> moves along the slant surface S of the slant portion <NUM>, and <FIG> is a diagram showing that the swelling detection panel <NUM> is entirely deviated from the slant surface S of the slant portion <NUM>.

Since the swelling detection panel <NUM> has an elastic force in itself as shown in the drawing, its shape is deformed to form a smooth curved surface when being moved along the slant surface S of the slant portion <NUM>.

In addition, if the pressure applied by the battery module <NUM> exceeds a threshold value, the swelling detection panel <NUM> moves to the second point C2 of the slant surface S, and then suddenly is deviated from the slant surface of the slant portion <NUM> to make strong contact with the contact sensor unit <NUM>. In addition, if the swelling detection panel <NUM> is deviated from the slant surface S, the elastic biased state is released, so the edge portion of the swelling detection panel <NUM> applies a strong pressure to the contact sensor unit <NUM> for a short period of time.

Therefore, if the contact sensor unit <NUM> is a piezoelectric sensor, when the edge of the swelling detection panel <NUM> is deviated from the slant surface S of the slant portion <NUM> and applies a pressure to the piezoelectric sensor, the piezoelectric sensor outputs a voltage signal corresponding to the pressure to the control unit <NUM>.

In addition, if the contact sensor unit <NUM> is a button switch, when the edge of the swelling detection panel <NUM> is deviated from the slant surface S of the slant portion <NUM> and applies a pressure to the button switch to press the button, the contact points of the button switch are connected to each other so that the voltage of the DC power supply connected to the button switch is applied to the control unit <NUM>.

As a result, it is possible to detect that the swelling detection panel <NUM> is deviated from the slant surface S while moving along the slant surface S of the slant portion <NUM> as the swelling phenomenon exceeds the threshold value since the shape of the battery module <NUM> is deformed due to swelling of the battery cell(s) included in the battery module <NUM>.

Preferably, the control unit <NUM> may determine that the swelling detection panel <NUM> is deviated from the slant surface S of the slant portion <NUM> when at least one swelling detection signal is received from the plurality of contact sensor units <NUM>.

Preferably, the control unit <NUM> may control the alarm unit <NUM> to output an alarm message if the swelling detection signal is received from the contact sensor unit <NUM>.

For example, control unit <NUM> visually outputs an alarm message through a display. As another example, the control unit <NUM> audibly outputs an alarm message or an alarm sound through a speaker.

The alarm message informs a user or driver of the device equipped with the battery module <NUM> that the battery cell(s) in the battery module <NUM> is in an excessively swelled state.

If the alarm message is output visually or audibly through alarm unit <NUM>, it preferable that the user or driver stops the operation of battery module <NUM>, then checks the state of battery module <NUM> and replaces the battery module <NUM> if necessary.

According to another embodiment, the alarm unit <NUM> may be provided in a load device to which the battery module <NUM> is mounted. For example, if the battery module <NUM> is mounted to an electric-driven vehicle, the alarm unit <NUM> may be an integrated vehicle information indicator provided to a dashboard of the electric-driven vehicle.

In this case, the control unit <NUM> may transmit the alarm message to a control system of the electric-driven vehicle through a communication interface. In addition, the control system may request a driver to check the battery module <NUM> by visually or audibly outputting an alarm message through the integrated vehicle information indicator.

Any known communication interface that supports communication between two different communication media may be used as the communication interface. The communication interface may support wired or wireless communication. Preferably, the communication interface may support CAN communication or daisy chain communication.

Since the alarm unit <NUM> may be provided to a load device as described, it should be understood that the present disclosure also includes an embodiment in which the control unit <NUM> outputs an alarm message to the alarm unit <NUM> through a control system provided in the load device.

Meanwhile, in the present disclosure, the swelling detection panel <NUM> may be used as a component of the battery module <NUM> by replacing the end plate of the battery module <NUM>.

<FIG> is a sectional view showing a battery module <NUM>' in case the swelling detection panel <NUM>' configures a part of the battery module <NUM>'.

Referring to <FIG>, the battery module <NUM>' may include a plurality of cartridge <NUM>. Each cartridge <NUM> surrounds at least one battery cell <NUM> included therein. The cartridge <NUM> may be made of a plastic or metal material with thermal conductivity. Electrodes (not shown) of the battery cell <NUM> are exposed at one side of the cartridge <NUM>, and the exposed electrodes may be electrically connected by means of welding.

The swelling detection panel <NUM>' may be coupled to an outermost cartridge <NUM> that surrounds the outermost battery cell. In one example, the outermost cartridge <NUM> is located at a rightmost side on the drawing.

Preferably, the swelling detection panel <NUM>' may have a snap-fit protrusion <NUM> on a surface opposite to the outermost cartridge <NUM>, and a snap-fit groove <NUM> may be provided at the surface of the outermost cartridge <NUM>. In this case, the swelling detection panel <NUM>' may be snap-fitted to the outermost cartridge <NUM> to serve as the end plate of the battery module <NUM>'. The snap-fit coupling allows the swelling detection panel <NUM>' connected to the battery module <NUM>' as an end plate to be easily separated from the outermost cartridge <NUM> when the swelling detection panel <NUM>' is deviated from the second point C2 of the slant surface S while moving along the slant surface S of the slant portion <NUM>.

If the battery module <NUM>' has the structure shown in <FIG>, it is preferable that the height of the battery module <NUM>' corresponds to the height of the internal space of the battery module housing <NUM>. That is, the height between the top and the bottom of the swelling detection panel <NUM>' may be substantially the same as the distance between the inner surface of the upper wall and the inner surface of the lower wall of the battery module housing <NUM>.

Unlike <FIG>, the snap-fit groove <NUM> may also be provided at an end wall of the battery module <NUM>'. In this case, the swelling detection panel <NUM>' may be snap-fitted to the end wall of the battery module <NUM>'. To this end, the location of the snap-fit protrusion <NUM> may be adjusted to correspond to the location of the snap-fit groove <NUM> formed at the end wall of the battery module <NUM>'.

In the present disclosure, the control unit <NUM> may optionally include a processor, an application-specific integrated circuit (ASIC), another chipset, a logic circuit, a register, a communication modem, a data processing device, or the like, known in the art to execute control logics. In addition, when the control logic is implemented in software, the control unit <NUM> may be implemented as a set of program modules. At this time, the program module may be stored in a memory and executed by a processor. The memory may be provided inside or outside the processor and be connected to the processor through various well-known computer components.

In addition, one or more of the various control logics of the control unit <NUM> may be combined, and the combined control logics may be written in a computer-readable code system and recorded in a computer-readable recording medium. The recording medium is not particularly limited as long as it is accessible by a processor included in a computer. As an example, the recording medium includes at least one selected from the group consisting of a ROM, a RAM, a register, a CD-ROM, a magnetic tape, a hard disk, a floppy disk and an optical data recording device. The code system may be distributed to a networked computer to be stored and executed therein. In addition, functional programs, codes and code segments for implementing the combined control logics may be easily inferred by programmers in the art to which the present disclosure belongs.

The swelling detection apparatus <NUM> according to the present disclosure may be included in a battery management system <NUM> as shown in <FIG>. The battery management system <NUM> controls the overall operation related to charging and discharging of a battery and is a computing system called a battery management system (BMS) in the art.

In addition, the swelling detection apparatus <NUM> according to the present disclosure may be mounted to an electric driving mechanism <NUM> as shown in <FIG>.

The electric driving mechanism <NUM> may be an electric power device movable by electricity, such as an electric-driven vehicle, an electric bicycle, an electric motorcycle, an electric train, an electric ship and an electric plane, or a power tool having a motor, such as an electric drill and an electric grinder.

<FIG> is a flowchart for illustrating a method for detecting swelling of a battery module according to an embodiment of the present disclosure.

Referring to <FIG>, first in Step S10, there are provided a battery module housing <NUM> defining a space in which the battery module <NUM> is mounted; a swelling detection panel <NUM> attached to one side surface of the battery module <NUM> and having an edge in contact with the inner surface of the battery module housing <NUM>; a slant portion <NUM> configured to protrude from the inner surface of the battery module housing <NUM> and having a slant surface S extending from a first location C1 adjacent to the edge of the swelling detection panel <NUM> to a second location C2 while forming a predetermined angle with the inner surface; a contact sensor unit <NUM> installed to the inner surface of the battery module housing <NUM> immediately adjacent to the end of the slant surface S corresponding to the second location C2; an alarm unit <NUM> configured to output an alarm message visually or audibly; and a control unit <NUM> operably coupled to the contact sensor unit <NUM> and the alarm unit <NUM>.

In Step S20, the contact sensor unit <NUM> outputs a swelling detection signal when the swelling detection panel <NUM> moves along the slant surface of the slant portion <NUM> to deviate from the second location C2 of the slant surface S and contact the contact sensor unit <NUM>.

In Step S20, each of the plurality of contact sensor units <NUM> may output a swelling detection signal.

In Step S30, if the control unit <NUM> receives at least one swelling detection signal from the plurality of contact sensor units <NUM>, the control unit <NUM> outputs an alarm message through the alarm unit <NUM>.

Preferably, the alarm unit <NUM> is a display or speaker. Accordingly, in Step S30, the control unit <NUM> may output the alarm message visually through the display or output the alarm message audibly through the speaker.

In the description of the various exemplary embodiments of the present disclosure, it should be understood that the element referred to as 'unit' is distinguished functionally rather than physically. Therefore, each element may be selectively integrated with other elements or each element may be divided into sub-elements for effective implementation control logic(s). However, it is obvious to those skilled in the art that, if functional identity can be acknowledged for the integrated or divided elements, the integrated or divided elements fall within the scope of the present disclosure.

detection panel <NUM> to a second location C2 while forming a predetermined angle with the inner surface; a contact sensor unit <NUM> installed to the inner surface of the battery module housing <NUM> immediately adjacent to the end of the slant surface S corresponding to the second location C2; an alarm unit <NUM> configured to output an alarm message visually or audibly; and a control unit <NUM> operably coupled to the contact sensor unit <NUM> and the alarm unit <NUM>.

Claim 1:
An apparatus (<NUM>) for detecting swelling of a battery module, comprising:
a battery module housing (<NUM>) configured to define a space in which the battery module (<NUM>) is placed;
a swelling detection panel (<NUM>) adapted to be attached to one side surface of the battery module and having an edge in contact with an inner surface of the battery module housing;
a slant portion (<NUM>) configured to protrude from the inner surface of the battery module housing and having a slant surface (S) extending from a first location (C1) adjacent to the edge of the swelling detection panel to a second location (C2) while forming a predetermined angle with the inner surface of the battery module housing;
a contact sensor unit (<NUM>) installed to the inner surface of the battery module housing immediately adjacent to an end of the slant surface corresponding to the second location;
an alarm unit (<NUM>) configured to output an alarm message visually or audibly; and
a control unit (<NUM>) operably coupled to the contact sensor unit and the alarm unit,
wherein the contact sensor unit is configured to output a swelling detection signal when the swelling detection panel moves along the slant surface to deviate from the second location so that the edge of the swelling detection panel contacts the contact sensor unit, and
the control unit is configured to control the alarm unit to output the alarm message when receiving the swelling detection signal.