Patent Description:
As opposed to non-rechargeable primary batteries, secondary batteries are rechargeable and they are used as a source of power for not only high-tech small electronic devices such as mobile phones, PDAs, and laptop computers, but also energy storage systems (ESSs), electric vehicles (EVs) or hybrid vehicles (HEVs).

Currently widely used secondary batteries include lithium ion batteries, lithium polymer batteries, nickel cadmium batteries, nickel hydride batteries, nickel zinc batteries, etc. The operating voltage of a unit secondary battery cell or a unit battery cell is about <NUM>. 5V to <NUM>. Accordingly, when higher output voltage and energy capacity are required, a plurality of battery cells may be connected in series to build a battery module, or two or more battery modules may be connected in series or in parallel and other components may be added to construct a battery pack. For example, the battery module may include a plurality of secondary batteries connected in series or in parallel, and the battery pack may include battery modules connected in series or in parallel to increase the capacity and output.

The secondary batteries are charged and discharged by electrochemical reactions, and during charging and discharging, heat is generated. In this instance, when heat is not released well, degradation may be accelerated, and in some cases, fires or explosion may occur. However, since the battery pack is an assembly of battery modules, when a secondary battery fire or explosion occurs in a specific battery module, there is a high risk that the chain ignition or chain explosion may occurs in adjacent battery modules. In particular, automobile battery packs need a safety device since fires or explosions may lead to personal injury.

Accordingly, most of battery packs include a cooler to monitor the temperature of each battery module and maintain the temperature at an appropriate level, but there is no device for preventing chain ignition or chain explosion in case of emergency.

Further prior art is described in <CIT>, forming the basis for the preamble of claim <NUM>, <CIT> and <CIT>.

The present disclosure is designed to solve the above-described problem, and therefore the present disclosure is directed to providing a battery pack with a safety device for preventing chain ignition or chain explosion to an adjacent battery module when an event occurs in a specific battery module in the battery pack.

These and other objects and advantages of the present disclosure can be understood by the following description, and will be apparent from the embodiments of the present disclosure. In addition, it will be readily appreciated that the objects and advantages of the present disclosure can be realized by means in claims.

According to an aspect of the present disclosure, there is provided a battery pack including a plurality of battery modules arranged along at least one direction, a single resistor being connected to a battery module in case of its abnormal operation among the plurality of battery modules to absorb energy, an event detection unit provided to detect the abnormal battery module, a switching module comprising a plurality of switches to connect or disconnect each of the plurality of battery modules to/from the resistor to selectively form a closed circuit, wherein the switches are kept in OFF state in normal conditions and selectively work in ON state only when an abnormal event occurs, and a control unit to receive information from the event detection unit and control the switching module to form a current path between the abnormal battery module and the resistor, when an abnormal event occurs.

The battery pack further includes partitions arranged in an alternating manner with the plurality of battery modules.

The partitions are provided as a cooling plate having a channel along which cooling water flows, and disposed in contact with at least one side of each battery module.

The resistor is in contact with the cooling plate that contacts an outermost battery module positioned at the outermost side in an arrangement order, and one surface of the cooling plate that contacts the outermost battery module is in contact with the outermost battery module, and the other surface of the cooling plate that contacts the outermost battery module is in contact with the resistor.

The resistor may include a block having a surface that contacts the cooling plate and a heating wire provided in the block.

The switching module may include switches each provided on a current path between a positive terminal of each battery module and one side of the resistor and a current path between a negative electrode of each battery module and the other side of the resistor.

The control unit may be configured to electrically connect the one abnormal battery module to the resistor by selectively turning on some of the switches.

The control unit may be configured to electrically connect the two or more abnormal battery modules to the resistor by selectively turning on some of the switches.

According to another aspect of the present disclosure, there is provided a vehicle including the battery pack. The vehicle may include an electric vehicle (EV) or a hybrid electric vehicle (HEV).

According to an aspect of the present disclosure, when it is expected that an event will occur at a specific battery module within a battery pack, it is possible to prevent fire or explosion propagation to an adjacent battery module by releasing energy of the corresponding battery module through a resistor.

According to another aspect of the present disclosure, it is possible to cool the battery module in normal condition as a partition with a cooling function, and when an event occurs, block heat generated from an abnormal battery module, thereby preventing fire or explosion propagation to battery modules, and at the same time, to cool the resistor while draining energy.

Other effects of the present disclosure can be understood by the following description, and will be more clearly understood by the embodiments of the present disclosure.

Therefore, the embodiments described herein and illustrations shown in the drawings are just some preferred embodiment of the present disclosure, but not intended to fully describe the technical aspects of the present disclosure, so it should be understood that a variety of other equivalents and modifications could have been made thereto at the time that the application was filed.

<FIG> is a block diagram of a battery pack according to an embodiment of the present disclosure, and <FIG> is a schematic diagram showing the main components of the battery pack according to an embodiment of the present disclosure.

Referring to <FIG> and <FIG>, the battery pack according to an embodiment of the present disclosure includes a plurality of battery modules <NUM>, a resistor <NUM>, an event detection unit <NUM>, a switching module <NUM>, a control unit <NUM> and a partition <NUM>.

Although not shown, the battery pack further includes a pack case to receive the battery modules <NUM> and various types of devices to control the charge and discharge of the battery modules <NUM>, such as a battery management system (BMS), a current sensor, a fuse, etc..

The battery modules <NUM> may be mounted in the pack case and arranged adjacent to each other along at least one direction. In this embodiment, although <FIG> shows three battery modules <NUM> arranged in one direction, the battery modules <NUM> may be arranged in various arrangements, for example, a 1X1 or 2X2 matrix arrangement, and there is no particular limitation on the number of battery modules <NUM>.

Each of the battery modules <NUM> includes battery cells <NUM>, and a module case <NUM> to receive the battery cells <NUM>. The battery cells <NUM> may include pouch-type secondary battery cells.

As shown in <FIG>, the pouch-type secondary battery cells may be stacked on top of each other and received in the internal space of the module case <NUM>. In addition, a space between the inner walls of the module case <NUM> and two edges of the pouch-type secondary battery cells may be filled with a thermal interface material (TIM) <NUM>. In this case, the TIM <NUM> may include a thermal pad having high thermal conductivity or resin. Heat generated from the pouch-type secondary battery cells may be transferred to the partition <NUM> in contact with the module case <NUM> through the TIM <NUM> and the two sides of the module case <NUM>.

The partition <NUM> and the battery module <NUM> may be arranged in an alternating manner such that the partition <NUM> is interposed between the battery modules <NUM>. For example, the internal space of the pack case may be divided into a plurality of spaces by the partitions <NUM>, and each battery module <NUM> may be installed in each space.

In this way, when each battery module <NUM> is placed in each space divided by the partition <NUM>, even if an event occurs in a specific battery module <NUM>, the partition <NUM> may prevent the event from affecting the other battery modules <NUM>, thereby minimizing damage (Here, the event refers collectively to an abnormal environment in which the battery module <NUM> is placed due to overheat, smoke, fire or explosion).

In the present disclosure, the partition <NUM> may be provided to divide the space in which each battery module <NUM> is installed and absorb heat from each battery module <NUM>. For example, the partition <NUM> may be provided in the form of a cooling plate <NUM> having a channel <NUM> therein and serve as a heat sink to absorb the heat of the battery module <NUM>.

Describing in more detail, the cooling plate <NUM> may be provided in the form of a plate having the channel <NUM> along which cooling water circulates and of size equal to or larger than the side of the battery module <NUM>, and may come into contact with one side of the battery module <NUM> to cool the battery module <NUM>.

Although not shown, the cooling plate <NUM> may further include cooling water inlet and outlet ports in communication with the channel <NUM> to allow cooling water to circulate along the channel <NUM> and extending to the inside/outside of the cooling plate <NUM>. The two ports may be connected to cooling pipes installed at the inside/outside of the battery pack to receive cooling water.

As described above, in the present disclosure, the cooling plates <NUM> may be interposed between the battery modules <NUM> to play a role of cooling each battery module <NUM> in normal condition, and when an event occurs, serve as a protective wall to block the flame or impact of the specific battery module <NUM> in which the event occurred, in order to protect the other battery modules <NUM>.

On the other hand, as described above, the battery pack according to the present invention includes the resistor <NUM>, the event detection unit <NUM>, the switching module <NUM> and the control unit <NUM> to minimize energy of the abnormal battery module <NUM> when the event occurs. This is to eliminate the risk of spreading the event to the surrounding battery module <NUM> by rapidly draining energy of the specific battery module <NUM> in which the event has occurred.

Hereinafter, an energy drain system of the specific battery module <NUM> according to an embodiment of the present disclosure will be described in detail with reference to <FIG> and <FIG> together with <FIG> and <FIG>.

As shown in <FIG> and <FIG>, each battery module <NUM> may be connected in parallel to one resistor <NUM> through the switching module <NUM>.

For reference, a plurality of resistors <NUM> corresponding to the number of battery modules <NUM> may be prepared and each battery module <NUM> and each resistor <NUM> may be matched on a one-to-one basis, but as the number of resistors <NUM> increases, the energy density per unit volume of the battery pack may decrease, the cost may increase and the burden of the assembly process may increase. Moreover, since the resistor <NUM> is configured to drain energy of the specific battery module <NUM> in abnormal operation, it is not good to put the plurality of resistors <NUM> in the battery pack. Accordingly, the present disclosure connects or disconnects one resistor <NUM> to/from each of the battery modules <NUM> through the switching module <NUM> to selectively form a closed circuit with the specific battery module <NUM>.

The event detection unit <NUM> is configured to detect the specific battery module <NUM>, i.e., the abnormal battery module <NUM> in which the event occurred among the battery modules <NUM>, and may include a gas detection unit <NUM> and a temperature measurement unit <NUM>.

The gas detection unit <NUM> may include at least one gas sensor provided in each battery module <NUM>. The gas sensor may include a combustible gas sensor, for example, a contact combustion sensor, a semiconductor sensor (Pd gate MOSFET), a ceramic gas sensor (ZnO, F<NUM>O<NUM>, SnO<NUM>, NiO, CoO), etc..

The temperature measuring unit <NUM> may include at least one temperature sensor provided in each battery module <NUM>. The temperature sensor may include a contact type temperature sensor that measures heat through contact with the battery cells <NUM> or a noncontact type temperature sensor that measures heat radiated from the battery cells <NUM>.

As shown in <FIG>, the switching module <NUM> includes switches, each provided on a current path between the positive terminal of each battery module <NUM> and one side of the resistor <NUM>, and a current path between the negative terminal of each battery module <NUM> and the other side of the resistor <NUM>.

The switches are kept in OFF state in normal condition, and selectively work in ON state only when an event occurs. The switches may include, for example, a mechanical or electronic relay switch.

The control unit <NUM> plays a role in receiving information from the event detection unit <NUM> and controlling the switching module <NUM> to form a current path between the abnormal battery module <NUM> and the resistor <NUM>.

The control unit <NUM> may be implemented in hardware using at least one of application specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processing devices (DSPDs), programmable logic devices (PLDs), field programmable gate arrays (FPGAs), microprocessors or electrical units for performing other functions. The control unit <NUM> may include memory.

The memory stores data, commands and software required for the overall operation of the device, and may include at least one type of storage medium of a flash memory type, a hard disk type, a solid state disk (SSD) type, a silicon disk drive (SDD) type, a multimedia card micro type, random access memory (RAM), static random access memory (SRAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM) or programmable read-only memory (PROM).

Specifically, an example of operation of the drain system when an event occurs in a specific battery module <NUM> is as follows.

For example, when the event occurs in the battery module M2, the gas sensor or the temperature sensor operates and a signal is transmitted to the control unit <NUM>. As shown in <FIG>, the control unit <NUM> controls the switches S<NUM> and S<NUM> into ON state and the switches S<NUM> and S<NUM> into OFF state based on the signal to allow the current to flow between the specific battery module M2 and the resistor <NUM>. Thus, the energy of the battery module M2 may be rapidly drained by the resistor <NUM>.

In contrast, when it is assumed that an event occurred in the battery module M3, the controller <NUM> may control the switches S<NUM> and S<NUM> into ON state and the switches S<NUM> and S<NUM> into OFF state to connect the battery module M3 to the resistor <NUM> in order to drain the energy.

In addition, when it is assumed that an event occurred in the battery module M1, the control unit <NUM> may control the switches S<NUM> and S<NUM> into ON state and the switches S<NUM> and S<NUM> into OFF state to connect the battery module M1 to the resistor <NUM> in order to drain the energy.

Meanwhile, heat energy generated by the resistor <NUM> during the energy drain process may be released through the above-described cooling plate <NUM>.

To this end, the resistor <NUM> may include a block <NUM> having a surface that contacts the cooling plate <NUM> and a heating wire <NUM> provided in the block <NUM>. One side and the other side of the heating wire <NUM> may be connected to each battery module <NUM>.

Referring back to <FIG>, the resistor <NUM> may be disposed in contact with the cooling plate <NUM> that contacts the battery module <NUM> positioned at the outermost side in an arrangement order. Here, one surface of the cooling plate <NUM> may be used for contact with the right surface of the battery module <NUM>, and the other surface of the cooling plate <NUM> may be used for contact with the resistor <NUM>.

As such, the present disclosure solves the problems with heat energy release of the resistor <NUM> and space efficient installation of the resistor <NUM> at the same time by installing the resistor <NUM> on the cooling plate <NUM> disposed on the outer surface of the outermost battery module <NUM>.

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

The battery pack according to another embodiment of the present disclosure has substantially the same configuration as the battery pack according to the above-described embodiment, only different in the configuration of the battery pack and the switching module <NUM>. A description of the same element will be omitted.

The switching module <NUM> of the above-described embodiment is configured to connect one specific battery module <NUM> in which an event occurred to the resistor <NUM>, while the switching module <NUM> of another embodiment of the present disclosure is configured to deal with events occurring in two or more battery modules <NUM> at the same time. In addition, the control unit <NUM> of this embodiment is configured to control the switching module <NUM> to electrically connect the at least one abnormal battery module <NUM> to the resistor <NUM> by selectively turning on some of the switches.

For example, the energy drain circuit according to this embodiment may be implemented as shown in <FIG>. It may be formed by adding, to the circuit of <FIG>, one more branch and switch each between node a and node c and between node b and node d, and one more switch between node a and node b. Additionally, in this embodiment, the switches S<NUM> to S<NUM> are placed in OFF state and the switch S<NUM> is placed in ON state in normal condition.

According to this energy drain circuit configuration, for example, when an event occurs in the battery module M2, the gas sensor or the temperature sensor operates and a signal is transmitted to the control unit <NUM>, the control unit <NUM> controls the switches S<NUM> and S<NUM>, S<NUM> into ON state and all the remaining switches S<NUM>, S<NUM>, S<NUM>, S<NUM> into OFF state based on the signal. In this case, the energy of the battery module M2 may be rapidly drained by the resistor <NUM>.

When it is assumed that an event occurs at the same time in the battery modules M1 and M3, as shown in <FIG>, the control unit <NUM> controls the switches S<NUM>, S<NUM>, S<NUM>, S<NUM> into ON state and the switches S<NUM>, S<NUM>, and S<NUM> into OFF state to connect the battery modules M1 and M2 to the resistor <NUM> in order to drain their energy.

Additionally, when it is assumed that an event occurred in the battery modules M2 and M3 at the same time, the control unit <NUM> may control the switches S<NUM>, S<NUM>, S<NUM> into ON state and all the remaining switches S<NUM>, S<NUM>, S<NUM>, S<NUM> into OFF state to connect the battery modules M2 and M3 to the resistor <NUM> in order to drain their energy.

Therefore, the battery pack according to another embodiment of the present disclosure may cope with a situation in which an event occurs in a plurality of battery modules <NUM> at the same time, and thus is safer than the battery pack of the above-described embodiment.

The battery pack according to the present disclosure as described above may be applied to vehicles such as electric vehicles or hybrid electric vehicles. Of course, the battery pack may be applied to energy storage systems or other IT products.

While the preferred embodiments of the present disclosure have been hereinabove illustrated and described, the present disclosure is not limited to the above-described particular preferred embodiments and it is obvious to those skilled in the art that various modifications may be made thereto without departing from the subject matter of the present disclosure as defined by the appended claims.

Claim 1:
A battery pack comprising:
a plurality of battery modules (<NUM>) arranged along at least one direction;
a single resistor (<NUM>) being connected to a battery module (<NUM>) in case of its abnormal operation among the plurality of battery modules (<NUM>) to absorb energy;
an event detection unit (<NUM>) provided to detect the abnormal battery module (<NUM>);
a switching module (<NUM>) comprising a plurality of switches (S1 to S4) to connect or disconnect each of the plurality of battery modules (<NUM>) to/from the resistor (<NUM>) to selectively form a closed circuit, wherein the switches are kept in OFF state in normal conditions and selectively work in ON state only when an abnormal event occurs; and
a control unit (<NUM>) to receive information from the event detection unit (<NUM>) and control the switching module (<NUM>) to form a current path between the abnormal battery module (<NUM>) and the resistor when an abnormal event occurs,
characterized by further comprising:
partitions (<NUM>) arranged in an alternating manner with the plurality of battery modules (<NUM>),
wherein the partitions (<NUM>) are provided as a cooling plate having a channel along which cooling water flows, and disposed in contact with at least one side of each battery module (<NUM>),
wherein the resistor (<NUM>) is in contact with the cooling plate that contacts an outermost battery module (<NUM>) positioned at the outermost side in an arrangement order, and
one surface of the cooling plate that contacts the outermost battery module (<NUM>) is in contact with the outermost battery module (<NUM>), and the other surface of the cooling plate is in contact with the resistor (<NUM>).