Patent Description:
Generally, a battery module mounted on a high-output product such as an electric vehicle includes a plurality of cells connected in series or in parallel, since a high voltage is to be supplied to a load.

If the battery module including the plurality of cells is discharged, the state of charges (SOCs) of the cells become different from each other due to the difference in the self-discharge rate of the cells.

If the battery module is continuously discharged in a state where the SOC is unbalanced, certain cells having low SOC are overdischarged, which makes it difficult to stably operate the battery module.

Conventionally, in order to solve the SOC imbalance between the cells, a buck method for eliminating the SOC imbalance between the cells by discharging cells having relatively high SOC and a boost method for eliminating the SOC imbalance between the cells by charging cells having relatively low SOC have been widely used.

The buck method has a problem that energy is wasted during the cell balancing process, and the boost method has a disadvantage that the circuit design becomes complicated because a charge circuit must be connected to every cell.

Among known cell balancing methods, there is a method of using an auxiliary battery as disclosed in <CIT>.

In the method of utilizing the auxiliary battery, the auxiliary battery is connected to cells having relatively high SOC, and the electric energy stored in the cells are discharged to charge the auxiliary battery. If so, the buck-type cell balancing is achieved, and energy is not wasted in this process.

Also, if the auxiliary battery is charged to some extent, the auxiliary battery is connected to cells having relatively low SOC to discharge the electric energy stored in the auxiliary battery so that the cells having relatively low SOC are charged. Then, unlike the existing boost method, it is possible to realize cell balancing by recycling the energy stored in the auxiliary battery even though there is no separate current source for generating the charging current.

However, the cell balancing method using the auxiliary battery has a problem that the auxiliary battery is rapidly degraded because the auxiliary battery is frequently charged and discharged. If the battery is degraded, internal resistance is increased to generate heat, and negative reaction occurs inside the battery to generate gas. Thus, if the auxiliary battery is degraded, safety of the cell balancing is deteriorated.

To solve this problem, the auxiliary battery should be exchanged periodically.

However, in the conventional technology, since the auxiliary battery is installed in the exterior of the battery along with a plurality of cells, it is troublesome to disassemble the exterior of the battery in order to exchange the auxiliary battery. In particular, in the case of an electric vehicle, since the battery is mounted below a body frame, lifting equipment and maintenance experts are needed to lift the electric vehicle and exchange the auxiliary battery.

As a solution thereto, as disclosed in <CIT>, the auxiliary battery is moved to a bonnet or a rear trunk of the vehicle, and the auxiliary battery and the main battery module are electrically connected to each other using a power cable.

However, even though the auxiliary battery is installed in a space directly accessible to a driver, such as a car bonnet or a rear trunk, it is still not easy for an unskilled person to exchange the auxiliary battery due to space constraints, resultant complicated wiring and safety reasons.

Further, <CIT> relates to a vehicle battery exchange system.

The present disclosure is designed to solve the problems of the related art, and therefore the present disclosure is directed to providing an auxiliary battery storage device, which allows an auxiliary battery to be electrically connected to a main battery while the auxiliary battery is being stored so that the auxiliary battery may be easily exchanged even by an unskilled person.

In one aspect of the present disclosure, there is provided an auxiliary battery storage device for storing an auxiliary battery that is used for performing cell balancing to a main battery adopted in an electric vehicle or supplying power to the main battery having low state of charge (SOC), the auxiliary battery storage device comprising: a case body formed in a box shape with an open top portion to have an inner space in which the auxiliary battery is stored; a case body cover coupled to the case body to open or close the open top portion of the case body; a terminal connection member fixed to an inner surface of the case body cover to contact a power terminal of the auxiliary battery when the top portion of the case body is closed by the case body cover; and a power cable configured to extend from the terminal connection member to the main battery.

The terminal connection member may include a protruding pin provided to be connected to or disconnected from the power terminal of the auxiliary battery in a receptacle manner.

The auxiliary battery storage device may further comprise a fastening member configured to fix the case body cover to the auxiliary battery, wherein the fastening member may be at least one bolt that has a gripping ring at a head portion thereof and is integrally connected to the case body cover and the auxiliary battery.

The case body includes a cable passage formed in at least one side plate thereof so that the power cable passes therethrough.

The case body cover may be hinged to one side plate of the case body, the cable passage may have two openings forming an entrance and an exit thereof so that the two openings are located at a top end and an outer side of the side plate, and the top end of the side plate at which the opening is located may be depressed down compared to other regions.

The case body has hooking grooves formed in side plates thereof facing each other, and the case body cover has hooking protrusions engaged with the hooking grooves so that the case body and the case body cover are coupled to each other, and the hooking protrusions are respectively moved by an electromagnetic force to be engaged with or disengaged from the hooking grooves.

The case body cover includes an electromagnet disposed at a position spaced apart from the hooking protrusion by a predetermined distance to pull the hooking protrusion by an electromagnetic force to be disengaged from the hooking groove; and a spring configured to elastically bias the hooking protrusion toward the hooking groove so that the hooking protrusion is engaged with the hooking groove.

The hooking protrusion may include a jaw engaged with the hooking groove; and a stopper configured to extend opposite to the jaw to support an upper surface of the auxiliary battery downward.

The auxiliary battery storage device may further comprise a lifting unit configured to move the auxiliary battery up and down to a preset height in the case body.

The lifting unit may include a support plate formed with a table shape to support the auxiliary battery inside the case body; a lifting rod configured to vertically pass through a lower plate of the case body and be connected to the support plate; and a driving motor configured to move the lifting rod up and down.

In another aspect of the present disclosure, there is also provided an electric vehicle, comprising the auxiliary battery storage device described above.

According to one embodiment of the present disclosure, since the auxiliary battery and the main battery may be electrically connected only by inserting the auxiliary battery into the case body and covering the case body by the case body cover, the auxiliary battery may be safely and easily exchanged even by an unskilled person.

According to another embodiment of the present disclosure, since the case body cover and the auxiliary battery are coupled to keep the gap therebetween constant, the electrical connection between the connector on the case body cover and the power terminal of the auxiliary battery may be stably maintained even when external shocks or vibrations are applied thereto.

According to still another embodiment of the present disclosure, it may become very easy to mount or separate the case body cover and to load or unload the auxiliary battery.

An auxiliary battery <NUM> mentioned in this specification may mean a battery used for performing cell balancing to a main battery <NUM> adopted in an electric vehicle <NUM> or supplying power to the main battery <NUM> with a low state of charge (SOC). For example, in the main battery <NUM>, the auxiliary battery <NUM> discharges the electric energy stored in cells having relatively high SOC to equalize the SOC with the other cells, and the discharged electric energy is used to charge the auxiliary battery <NUM>. In addition, the auxiliary battery <NUM> is connected to cells having relatively low SOC to discharge the electric energy stored in the auxiliary battery <NUM> so that the cells having relatively low SOC are charged to equalize the SOC with the other cells.

The auxiliary battery <NUM> may be installed at a location at which the auxiliary battery <NUM> may be easily maintained and easily exchanged at emergency separately from the main battery <NUM>. An auxiliary battery storage device <NUM> may be understood as an article used to accommodate and store the auxiliary battery <NUM>. The auxiliary battery storage device <NUM> according to the present disclosure may also be used to accommodate a fuel cell (serving for starting a general vehicle or supplying power to various devices) having a similar function and structure to the auxiliary battery <NUM>.

As shown in <FIG>, the main battery <NUM> may be coupled to a lower frame of the vehicle, and the auxiliary battery <NUM> may be mounted to a bonnet or a rear trunk of the vehicle. The main battery <NUM> and the auxiliary battery <NUM> may be electrically connected through a power cable <NUM>.

If the auxiliary battery <NUM> breaks down or has a trouble, a driver may open the bonnet or the rear trunk to exchange the auxiliary battery <NUM>. The auxiliary battery storage device <NUM> according to the present disclosure is a device for casing the auxiliary battery <NUM>, and when the auxiliary battery <NUM> is exchanged, a new auxiliary battery <NUM> may be accommodated in the auxiliary battery storage device <NUM> and simultaneously connected to the auxiliary battery storage device <NUM>.

As will be described later in detail, if the auxiliary battery storage device <NUM> according to the present disclosure is used, a new auxiliary battery <NUM> is electrically connected to the main battery <NUM> only by mounting the new auxiliary battery <NUM> to the storage device. Thus, the auxiliary battery <NUM> may be exchanged safety and easily even by an unskilled person. Hereinafter, the auxiliary battery storage device <NUM> will be described in detail with reference to <FIG>.

<FIG> is a perspective view schematically showing the auxiliary battery storage device according to an embodiment of the present disclosure, <FIG> is a cross-sectioned view schematically showing the auxiliary battery storage device according to an embodiment of the present disclosure, and <FIG> is an enlarged view showing a power cable and an inlet of a cable passage of <FIG>.

Referring to <FIG>, the auxiliary battery storage device <NUM> according to an embodiment of the present disclosure includes a case body <NUM>, a case body cover <NUM>, a terminal connection member <NUM>, and a power cable <NUM>. The auxiliary battery storage device <NUM> may be disposed at, for example, a bonnet or a rear trunk.

The case body <NUM> may include a lower plate <NUM> and four side plates <NUM>, <NUM> forming walls, and may be formed in a box shape with an open top portion.

The auxiliary battery <NUM> may be placed in the inner space formed inside the case body <NUM>. At this time, a power terminal 3a of the auxiliary battery is provided to face the open top portion of the case body <NUM>.

Though not shown in the figures for convenience, the lower plate <NUM> of the case body <NUM> may be fixed horizontally to a bottom surface of the bonnet or the trunk by a component such as a bracket.

The side plates <NUM>, <NUM> of the case body <NUM> define the inner space of the case body <NUM>. In particular, the side plates <NUM>, <NUM> may be formed at least higher than the height of the auxiliary battery <NUM> so that the auxiliary battery <NUM> is fully inserted into the inner space of the case body <NUM>. The auxiliary battery <NUM> accommodated in the case body <NUM> may be protected from external impact by the side plates <NUM>, <NUM>. Also, the side plates <NUM>, <NUM> may be used as a wiring path of the power cable <NUM>, explained later.

Meanwhile, in this embodiment, the case body <NUM> is designed to have a rectangular parallelepiped box shape, but the shape of the case body <NUM> may be changed depending on the volume or the installation place of the auxiliary battery <NUM>.

The case body cover <NUM> is a component that closes the open top portion of the case body <NUM>. The case body cover <NUM> according to this embodiment has a plate shape sized corresponding to the area of the open top portion of the case body <NUM> and is provided to be hinged to the case body <NUM>.

For example, the case body cover <NUM> is rotatably coupled to any one side plate <NUM> of the side plates <NUM>, <NUM> of the case body <NUM> by a hinge to open and close the top portion of the case body <NUM>. That is, the top portion of the case body <NUM> may be opened or closed by rotating the case body cover <NUM>.

A terminal connection member <NUM> serving as is a component electrically connected to the power terminal 3a of the auxiliary battery is fixedly coupled to an inner surface of the case body cover <NUM>.

The terminal connection member <NUM> according to this embodiment may be configured as a male connector having protruding pins <NUM>, and the power terminal 3a of the auxiliary battery may be configured as a female connector having a socket that may be coupled with the protruding pins <NUM> in a receptacle manner.

As shown in <FIG>, the terminal connection member <NUM> may be disposed at a center of the inner surface of the case body cover <NUM> so that the terminal connection member <NUM> is connected to the power terminal 3a of the auxiliary battery when the top portion of the case body <NUM> is completely closed by the case body cover <NUM>.

Thus, if the top portion of the case body <NUM> is closed by the case body cover <NUM>, the protruding pins <NUM> of the terminal connection member <NUM> are connected to the power terminal 3a of the auxiliary battery, and if the case body cover <NUM> is opened, the protruding pins <NUM> of the terminal connection member <NUM> are disconnected from the power terminal 3a of the auxiliary battery.

The position of the terminal connection member <NUM> may be changed corresponding to the position of the power terminal 3a of the auxiliary device. Namely, the terminal connection member <NUM> may be located at any position on the inner surface of the case body cover <NUM> as long as the terminal connection member <NUM> contacts the power terminal 3a of the auxiliary battery when the top portion of the case body <NUM> is closed by the case body cover <NUM>. In addition, the main and the female connectors may be connected in any way such as a point contact method other than the receptacle method, as long as the main and the female connectors can be contacted with each other.

Meanwhile, the auxiliary battery storage device according to the present disclosure may further include a fastening member 20a that fixes the case body cover <NUM> and the auxiliary battery <NUM> in a state where the top portion of the case body <NUM> is closed by the case body cover <NUM>.

As the fastening member 20a, a bolt may be employed having a gripping ring formed in a head portion thereof. As shown in <FIG>, a bolt may be inserted into bolt fastening holes H, which are provided in corner regions of the case body cover <NUM> and the auxiliary battery <NUM> in one-to-one relationship, to integrally fix the case body cover <NUM> and the auxiliary battery <NUM>. At this time, a worker may grip the gripping ring and turn the bolt, so that the bolt may be tightened without using a tool such as a spanner.

In this way, as the case body cover <NUM> and the auxiliary battery <NUM> are fastened by the bolt, a gap may not be generated between the case body cover <NUM> and the auxiliary battery <NUM> even when shock or vibration is applied thereto while the vehicle is running. Thus, the contact state between the main and the female connectors <NUM>, 5a may be stably maintained.

The power cable <NUM> is a component for electrically connecting the auxiliary battery <NUM> and the main battery <NUM> and allows the auxiliary battery <NUM> to be separated from the main battery <NUM> and placed in a trunk space that is easily accessible to the driver.

The power cable <NUM> is connected to the main battery <NUM> having one side connected to the terminal connection member <NUM> and the other side installed to the body frame. Thus, if the top portion of the case body <NUM> is closed by the case body cover <NUM>, the power of the auxiliary battery <NUM> may be supplied to the main battery <NUM>.

As shown in <FIG> and <FIG>, the power cable <NUM> according to this embodiment may extend from the terminal connection member <NUM> through the side plate <NUM> of the case body <NUM> to the outside of the case body <NUM> toward the main battery <NUM>. To this end, the side plate <NUM> of the case body has a hollow structure in which a cable passage is provided.

Two openings forming an entrance and an exit of the cable passage are respectively located at a top end and an outer side of the side plate <NUM> to which the case body cover <NUM> are hinged, and the cable passage may be formed to extend straightly downward from an inlet <NUM> located at the top end of the side plate <NUM> approximately to an outlet adjacent to a bottom end of the side plate <NUM>.

The top portion of the side plate <NUM> where the inlet <NUM> of the cable passage is located may be depressed compared to regions other than the top portion. In other words, as shown in <FIG>, the top portion of the side plate <NUM> corresponding to the inlet <NUM> of the cable passage may be concavely recessed relative to other portions.

Since the cable passage is provided in the side plate <NUM> of the case body <NUM> as described above, the interference between the power cable <NUM> and the auxiliary battery <NUM> in the case body <NUM> may be minimized. Also, when the top portion of the case body <NUM> is closed by the case body cover <NUM>, the power cable <NUM> may not interfere with the case body cover <NUM> at all.

If the auxiliary battery storage device <NUM> according to the present disclosure having the above structure and operation is used, it is possible to protect the auxiliary battery <NUM> from external impact. Moreover, since the power terminal 3a of the auxiliary battery is connected to or disconnected from the power cable <NUM> by putting the auxiliary battery <NUM> into the case body <NUM> and opening or closing the case body <NUM> by the case body cover <NUM>, it is not necessary to carry out the wiring work in a state of wearing safety equipment, different from the conventional art. Thus, the auxiliary battery <NUM> may be safely and easily exchanged even by an unskilled person.

Subsequently, an auxiliary battery storage device <NUM> according to another embodiment of the present disclosure will be described. The same reference numerals as those in the former embodiment denote the same components and will not be described in detail again, and features different from the former embodiment will be described in detail.

<FIG> and <FIG> are cross-sectioned views showing an auxiliary battery storage device <NUM> according to another embodiment of the present disclosure to illustrate the process of mounting or separating the case body cover <NUM> and loading or unloading the auxiliary battery <NUM>, and <FIG> are diagrams for illustrating the states before and after a hooking protrusion <NUM> of the case body cover <NUM> is operated according to another embodiment of the present disclosure.

The auxiliary battery storage device <NUM> according to another embodiment of the present disclosure is configured to allow the worker to exchange the auxiliary battery <NUM> more conveniently than the former embodiment. In the former embodiment, when fixing the case body cover <NUM> and the auxiliary battery <NUM>, the worker must directly fasten the bolt, and if there is no tool such as a spanner, the fastening force for the bolt may not be sufficient. Meanwhile, in this embodiment, the case body cover <NUM> and the auxiliary battery <NUM> may be fixed and separated by turning on/off an opening/closing button, thereby eliminating the inconvenience of the former embodiment.

As shown in <FIG> and <FIG>, hooking grooves <NUM> are provided at the two side plates <NUM>, <NUM> of the case body <NUM>, and hooking protrusions <NUM> engaging with the hooking grooves <NUM> are provided on the case body cover <NUM>. The case body cover <NUM> may close or open the case body <NUM> as the hooking protrusions <NUM> and the hooking grooves <NUM> are engaged or disengaged. At this time, the hooking protrusion <NUM> may be configured to be horizontally movable by an electromagnetic force so as to be inserted into or released from the hooking groove <NUM>.

As shown in <FIG>, the case body cover <NUM> of this embodiment includes an electromagnet <NUM> and a pair of springs <NUM> therein. The hooking protrusion <NUM> may be mounted vertically to the case body cover <NUM> in a state where the top end of the hooking protrusion <NUM> is connected to the pair of springs <NUM>.

The pair of springs <NUM> may be spaced apart from each other by a predetermined distance in the width direction of the hooking protrusion, and the electromagnet may be disposed in the middle between the springs <NUM> while keeping a constant gap from the hooking protrusion <NUM>. Four assemblies in which the electromagnet <NUM>, the pair of springs <NUM> and the hooking protrusion <NUM> are combined may be assembled at four corners of the case body cover <NUM>, respectively.

The operating mechanism of the hooking protrusion <NUM> will be briefly described. The electromagnet <NUM> is a metal rod around which a coil is wound. If an electric current flows through the coil, an electromagnetic force is generated. Thus, as shown in <FIG>, if a switch is turned on so that a current flows through the electromagnet <NUM>, the hooking protrusion <NUM> is pulled toward the electromagnet <NUM> and released from the hooking groove <NUM>. Here, at least the top end of the hooking protrusion <NUM> is made of metal.

Conversely, as shown in <FIG>, if the switch is turned off to cut off the current to the electromagnet <NUM>, the hooking protrusion <NUM> may be elastically biased toward the hooking groove <NUM> by the elastic force of the spring <NUM> to engage with the hooking groove <NUM>.

Even though an operation button for turning on/off the switch is conceptually depicted in the figures, the operation button may be disposed at an outer surface of the case cover <NUM>, or the operation button may also be configured to turn the switch on/off wirelessly.

In particular, as shown in the enlarged view of <FIG>, the hooking protrusion <NUM> may further include a top end mounted to the case body cover <NUM> in a state of being connected to the spring <NUM>, and a jaw 21a and a stopper 21b disposed below the top end.

The jaw 21a is a portion that is substantially engaged with the hooking groove <NUM> in the hooking protrusion <NUM>. That is, depending on the location of the jaw 21a with respect to the hooking groove <NUM> by the electromagnet <NUM> and the spring <NUM>, it is determined whether the case body cover <NUM> and the case body <NUM> are coupled or separated.

The stopper 21b is a portion that extends horizontally opposite to the jaw 21a. The stopper 21b may extend at least to a position at which the stopper may contact the upper surface of the auxiliary battery <NUM>. As shown in <FIG>, when the top portion of the case body <NUM> is closed by the case body cover <NUM>, the stopper 21b supports the upper surface of the auxiliary battery <NUM> downward.

Since the case body cover <NUM> is engaged with the case body <NUM> and the auxiliary battery <NUM> is supported downward by the stopper 21b of the case body cover <NUM>, the gap between the case body cover <NUM> and the auxiliary battery <NUM> may be kept constant. Thus, it is possible to prevent a clearance from being formed between the male connector of the case body cover <NUM> and the female connector of the power terminal 3a of the auxiliary battery.

Meanwhile, the auxiliary battery storage device <NUM> according to another embodiment of the present disclosure may further include a lifting unit <NUM> for supporting a lower portion of the auxiliary battery <NUM> and moving the auxiliary battery <NUM> up and down to a preset height in the inner space of the case body <NUM>. The lifting unit <NUM> relieves the effort of the worker when inserting or removing the auxiliary battery <NUM> into/from the case body <NUM>. In particular, if the inner space of the case body <NUM> has a great depth and the auxiliary battery <NUM> is heavy due to a very large capacity, the lifting unit <NUM> is very useful.

Referring to <FIG> and <FIG>, the lifting unit <NUM> may include a support plate <NUM> having a table shape and disposed to contact the lower surface of the auxiliary battery <NUM>, a lifting rod <NUM> vertically connected to the support plate <NUM>, and a driving motor <NUM> for moving the lifting rod <NUM> up and down.

The support plate <NUM> is formed in a plate shape sized corresponding to the lower surface of the auxiliary battery 3a and is provided to have a substantially table shape to stably support the auxiliary battery <NUM>. A rubber pad may be further provided on the upper surface of the support plate <NUM> to secure adhesion with the auxiliary battery <NUM>.

One side of the lifting rod <NUM> is connected to a lower portion of the support plate <NUM>, and the other side thereof is connected to the driving motor <NUM> through the lower plate <NUM> of the case body <NUM>. At least two lifting rods <NUM> may be provided to be vertically moved by the driving motor <NUM>. For example, the lifting rod <NUM> may be moved up and down in a rack and pinion manner.

The driving motor <NUM> is a component for moving the lifting rod <NUM> up and down. Although not shown in detail, for example, if the driving motor <NUM> rotates a pinion, the pinion may move a rack corresponding to the lifting rod <NUM> up and down. As an alternative of the lifting unit <NUM> by the driving motor <NUM>, a hydro-pneumatic actuator that generates an impellent force in the vertical direction may be used.

The driving motor <NUM> may be embedded under the support surface where the case body <NUM> may be placed. For example, a switch for operating the driving motor <NUM> may be placed on the side surface of the case body cover <NUM> or the case body <NUM> along with the switch for manipulating the hooking protrusion <NUM>.

The auxiliary battery storage device <NUM> according to another embodiment of the present disclosure is used, it will be very easy to attach or detach the case body cover <NUM> to/from the case body <NUM>, fix the case body cover <NUM> and the auxiliary battery <NUM> to each other, and load or unload the auxiliary battery <NUM>.

The auxiliary battery storage device <NUM> may be applied to a vehicle such as an electric vehicle and a hybrid electric vehicle, which uses the auxiliary battery <NUM> or a similar fuel cell.

Claim 1:
An auxiliary battery storage device (<NUM>) for storing an auxiliary battery (<NUM>) that is used for performing cell balancing to a main battery (<NUM>) adopted in an electric vehicle or supplying power to the main battery (<NUM>) having low state of charge, SOC, the auxiliary battery storage device (<NUM>) comprising:
a case body (<NUM>) formed in a box shape with an open top portion to have an inner space in which the auxiliary battery (<NUM>) is stored;
a case body cover (<NUM>) coupled to the case body (<NUM>) to open or close the open top portion of the case body (<NUM>);
characterized in that
said auxiliary battery storage device (<NUM>) further comprises:
a terminal connection member (<NUM>) fixed to an inner surface of the case body cover (<NUM>) to contact a power terminal (3a) of the auxiliary battery (<NUM>) when the top portion of the case body (<NUM>) is closed by the case body cover (<NUM>); and
a power cable (<NUM>) configured to extend from the terminal connection member (<NUM>) to the main battery (<NUM>),
the case body (<NUM>) has hooking grooves (<NUM>) formed in side plates (<NUM>, <NUM>) thereof facing each other, and the case body cover (<NUM>) has hooking protrusions (<NUM>) engaged with the hooking grooves (<NUM>) so that the case body (<NUM>) and the case body cover (<NUM>) are coupled to each other,
the hooking protrusions (<NUM>) are respectively moved by an electromagnetic force to be engaged with or disengaged from the hooking grooves (<NUM>), and
the case body cover (<NUM>) includes:
an electromagnet (<NUM>) disposed at a position spaced apart from the hooking protrusion (<NUM>) by a predetermined distance to pull the hooking protrusion (<NUM>) by an electromagnetic force to be disengaged from the hooking groove (<NUM>); and
a spring (<NUM>) configured to elastically bias the hooking protrusion (<NUM>) toward the hooking groove (<NUM>) so that the hooking protrusion (<NUM>) is engaged with the hooking groove (<NUM>).