Battery module and energy storage device

Abstract

Embodiments of the present application relate to a battery module and an energy storage device, and provide an energy storage device including: a battery rack including a plurality of battery modules; and a rack fuse configured to cut off a circuit when overcurrent occurs in the battery rack, wherein each of the plurality of battery modules includes a battery cell and a module fuse that cuts off a circuit when overcurrent occurs in the battery module, wherein the module fuse has a voltage specification capable of corresponding to an output voltage of the battery rack, and has a short circuit specification lower than that of the rack fuse.

Description

TECHNICAL FIELD

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit of Korean Patent Application No. 10-2020-0044257, filed April 10, 2020, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein in its entirety by reference. TECHNICAL FIELD

[0004] Embodiments of the present application relate to a battery module and an energy storage device, and more particularly, to a battery module and an energy storage device provided with a fuse for blocking overcurrent. BACKGROUND

[0005] Recently, as electronic devices such as smartphones, electric vehicles are popularized, and infrastructure for an energy storage system (ESS) is popularized, research on secondary batteries as a power supply source is also actively conducted.

[0006] In the case of an ESS, a large amount of electric energy needs to be stored, and a high power is also required. Therefore, in the ESS, a secondary battery is provided in the form of a battery rack including a plurality of battery modules and a rack controller managing the plurality of battery modules. Each of the plurality of battery modules further includes a battery pack in which a plurality of battery cells are connected in series and / or in parallel, and a module controller managing the operation of the battery pack.

[0007] Since a short circuit in the ESS can cause a serious accident such as a fire, for safety, various configurations are provided to block such a short circuit. Currently, a fuse is connected as a passive element in a battery system such as an ESS. When a short circuit occurs, overcurrent is cut off by the fuse for a short time, and preparation for a short circuit accident is made.

[0008] The fuse in the battery rack has a structure that cannot cope with a module-level short circuit. Therefore, a module fuse is also provided in the battery system to satisfy the United Nations Transportation Testing (UN / DOT 38.3) standard. The UN / DOT 38.3 is a test procedure that ensures the safety of lithium ion batteries when transported. The UN / DOT 38.3 contains the following: when a battery is transported in a module state, the module needs to be protected from a short circuit, and a module fuse is provided to satisfy this requirement. Regarding the module fuse, a fuse having a voltage specification satisfying the module voltage is selected so that there is no problem in a short circuit test of the installed battery module.

[0009] However, in the case where a short circuit occurs in the battery rack after the battery module is finally installed to the battery rack, if the module fuse operates and melts before the rack fuse, there is a possibility that the system voltage, i.e., the output voltage of the battery rack, is captured by the module fuse. In this case, the module fuse cannot withstand the system voltage, can be damaged, and other components can also be damaged. SUMMARY

[0010] [PROBLEMS TO BE SOLVED BY THE INVENTION]

[0011] An embodiment of the present invention is made to solve the above problems, and an object of the present invention is to provide a battery module and an energy storage device that prevent deterioration in price competitiveness and energy density while being safe.

[0012] [TECHNICAL SOLUTION]

[0013] To solve the above technical problems, according to an aspect of an embodiment of the present invention, an energy storage device includes a battery rack including a plurality of battery modules, and a rack fuse configured to cut off a circuit when overcurrent occurs in the battery rack, wherein each of the plurality of battery modules includes a battery cell and a module fuse that cuts off a circuit when overcurrent occurs in the battery module, wherein the module fuse has a voltage specification capable of corresponding to an output voltage of the battery rack, and has a short circuit specification lower than a short circuit specification of the rack fuse.

[0014] According to another feature of the present embodiment, the module fuse can be cut off later than the rack fuse when a short circuit occurs in the battery rack.

[0015] According to another feature of the present embodiment, the module fuse can cut off only the rack fuse when a short circuit occurs in the battery rack.

[0016] According to another feature of the present embodiment, the module fuse can start to melt later than when the rack fuse is completely melted when a short circuit occurs in the battery rack.

[0017] According to another feature of the present embodiment, the module fuse can not operate when a short circuit occurs in the battery rack and the rack fuse is cut off.

[0018] According to another feature of the present embodiment, the module fuse can be cut off when a short circuit occurs in the battery module.

[0019] To solve the above-described technical problem, according to another aspect of an embodiment of the present application, a battery module in an energy storage device that is used by a plurality of battery modules in a battery rack, and that includes a rack fuse that cuts off a circuit when overcurrent occurs, includes a plurality of battery cells, and a module fuse configured to cut off a circuit when overcurrent occurs, wherein the module fuse has a voltage specification that can correspond to an output voltage of the battery rack, and has a short-circuit specification that is lower than a short-circuit specification of the rack fuse.

[0020] According to another feature of the present embodiment, the module fuse can start to melt later than when the rack fuse completely melts when a short circuit occurs in the battery rack.

[0021] According to another feature of the present embodiment, the module fuse can be cut off when a short circuit occurs in the battery module.

[0022] [Effects of the Invention]

[0023] Due to the above-described configuration, it is possible to provide a battery module and an energy storage device that are safe while preventing deterioration in price competitiveness and energy density. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 is a diagram illustrating a configuration of an energy storage device according to an embodiment of the present application;

[0025] Figure 2 is a diagram illustrating a configuration of a battery module according to an embodiment of the present application;

[0026] Figure 3 is a schematic circuit diagram of an energy storage device according to an embodiment of the present application.

[0027] Figure 4 is a diagram illustrating an example in which a short circuit occurs in an energy storage device according to Figure 3 the present application.

[0028] Figure 5 is a diagram illustrating another example in which a short circuit occurs in an energy storage device according to Figure 3 the present application. DETAILED DESCRIPTION

[0029] Hereinafter, various embodiments of the present application will be described in detail with reference to the accompanying drawings. In this document, the same components in the drawings are designated by the same reference numerals and repeated description is omitted.

[0030] For the various embodiments of the present application disclosed herein, specific structural or functional descriptions have been set forth only for the purpose of describing the embodiments of the present application, and the various embodiments of the present application can be implemented in various forms, and should not be interpreted as being limited to the embodiments described herein.

[0031] Expressions such as "1st", "2nd", "first", or "second" used in various embodiments can modify various elements regardless of their order and / or importance, and do not limit the corresponding elements. For example, the first component can be referred to as the second component, and similarly, the second component can be renamed and referred to as the first component without departing from the scope of the present application.

[0032] The terms used herein are only used to describe specific embodiments, and are not intended to limit the scope of other embodiments. The singular form of the term can include the plural form unless otherwise specified.

[0033] Figure 1 is a diagram showing a configuration of an energy storage device according to an embodiment of the present application.

[0034] Referring to Figure 1 , the energy storage device 1 is a unit that stores energy in an energy storage system. The energy storage system can be configured to include a plurality of energy storage devices 1. The energy storage device 1 is provided in the form of a battery rack. The battery rack is equipped with a plurality of battery modules 10 and a rack controller that controls the entire battery rack at the chassis. Hereinafter, the energy storage device and the battery rack can be used in combination.

[0035] The energy storage device 1 can include a battery module composed of a secondary battery that can be recharged and re-discharged. The energy storage device 1 can supply stored power to a load or a system. In addition, the energy storage device 1 can be charged by receiving power from the system.

[0036] As Figure 1 shown, the energy storage device 1 can include a plurality of battery modules 10-1 to 10-N, a rack controller (Rack Battery Management System (RBMS)), a rack battery protection unit (RBPU), and the like.

[0037] A plurality of battery modules 10-1 to 10-N are unit assemblies that can be installed on the energy storage apparatus 1, and each of the plurality of battery modules 10-1 to 10-N is configured to charge and discharge electric power. (Hereinafter, when it is not necessary to separate and describe the plurality of battery modules, the reference numeral is described as 'battery module 10'.) The battery module 10 is an assembly that can be individually transported before being assembled into a battery rack as the energy storage apparatus 1. According to the required specifications of the energy storage apparatus 1, the plurality of battery modules 10 can be connected in series and / or in parallel with each other within the energy storage apparatus 1. That is, the plurality of battery modules 10 can provide a required output according to the series and / or parallel connection configuration.

[0038] Each of the battery modules 10 can include a battery pack 11, a module controller 12, a switching unit 13, and a module BPU 14. Figure 2 FIG. 1 is a diagram illustrating a configuration of a battery module according to an embodiment of the present application.

[0039] Referring to Figure 2 The battery pack 11 can include one or more battery cells C, which are unit assemblies for storing electric power. According to the required specifications of the battery pack 11, a plurality of battery cells can be connected in series and / or in parallel with each other. That is, the number and connection type of the battery cells C can be determined according to the required output (voltage, current, etc.) of the battery module 10. The battery cells C can be lithium-ion (Li-ion) batteries, lithium-ion polymer (Li-ion polymer) batteries, nickel-cadmium (Ni-Cd) batteries, nickel-hydrogen (Ni-MH) batteries, etc. If they are rechargeable batteries, they are not limited thereto.

[0040] The module controller 12 (or'module BMS') controls and manages the overall operation of the battery module 10. The module controller 12 can detect the temperature of the battery module 10 and the voltage and current output from the battery module 10. The battery module 10 can calculate parameters such as SOC, i.e., state of charge, or SOH indicating the degree of deterioration, according to values such as temperature, voltage, and current detected by direct measurement or received from the outside. In order to detect voltage, current, temperature, etc., the module controller 12 can provide a measurement device such as a sensor at an appropriate location in the battery module 10 or the energy storage apparatus 1.

[0041] The module controller 12 can transmit values such as temperature, voltage, and current or calculated values such as SOC and SOH to an external device. The external device can be an upper controller, and in the present embodiment, values such as the detected temperature, voltage, and current or values such as the calculated SOC and SOH can be transmitted to the rack controller 20 that manages the energy storage apparatus 1.

[0042] The module controller 12 can execute a computer program to control and manage the overall operation of the battery module 10, and can include various components such as a microcomputer as a controller for controlling the overall operation of the module controller 12, a memory for storing a computer program required for the operation of the module controller 12, input / output devices such as sensors and measuring devices, a communication device for communication with external devices, and other peripheral circuits.

[0043] The switching unit 13 can be a device that supplies power to a system or a load or receives power from a system when the battery module 10 is charged or discharged. The switching unit 13 can be a relay or a contactor. The operation of the switching unit 13 can be controlled by the module controller 12.

[0044] The module BPU 14 can include components for stable operation of the battery module 10. The module BPU 14 can include a cooling device such as a cooling fan for controlling the temperature in the battery module 10. In addition, the module BPU 14 can include a module fuse MF for cutting off a current path when overcurrent occurs due to a short circuit or the like. That is, the battery module 10 can include a module fuse MF that cuts off a circuit when overcurrent occurs.

[0045] When overcurrent flows through the battery module 10, the module fuse MF is melted by heat generated by electric energy. When the module fuse MF is melted to block the flow of current, a predetermined voltage is applied therebetween. In addition, the module fuse MF must be able to withstand the predetermined voltage applied across the two terminals after melting. The specific specifications and characteristics of the module fuse MF will be described later.

[0046] The rack controller 20 can control a relay for charging a battery rack or discharging a battery rack to a system or a load. The rack controller 20 can monitor various parameters (e.g., voltage, current, temperature, etc.) in the battery rack and control each protection device in the rack BPU 30 based on the results.

[0047] The rack controller 20 can communicate with the module controller 12 included in each of the plurality of battery modules 10 included in the battery rack. The rack controller 20 can receive data on the state of the battery pack 11 from the module controller 12 and control the protection devices in the rack BPU 30 based on the data. In addition, the rack controller 20 can transmit a control signal for controlling the operation of the battery module 10 to the module controller 12 based on the data from the module controller 12. The rack controller 20 can communicate with the plurality of module controllers 12 through wired and / or wireless.

[0048] Like the module BPU 14, the rack BPU 30 can include components for stable operation of the battery rack. The rack BPU 30 can include a cooling device, such as a cooling fan, for controlling the temperature in the battery rack. Further, the rack BPU 30 can include a rack fuse RF for cutting off the current path when overcurrent occurs due to a short circuit or the like. That is, the energy storage device 1 can include a rack fuse RF that cuts off the circuit when overcurrent occurs in the battery rack. The specific specifications and characteristics of the rack fuse (RF) will be described later.

[0049] In the energy storage device 1 configured as described above, at least some of the plurality of battery modules 10 are connected in series with the rack fuse RF. Figure 3 is a schematic circuit diagram of an energy storage device according to an embodiment of the present application.

[0050] Reference Figure 3 , at least some of the battery modules 10-1 to 10-N among the plurality of battery modules 10 are connected in series with each other, and the rack fuse RF is connected in series with the series-connected battery modules 10-1 to 10-N. RACK(+) and RACK(-) represent output terminals of the battery rack. In Figure 3 , for ease of explanation, only one battery cell is shown as the battery pack 11, and only the battery pack 11 and the module fuse MF are shown.

[0051] In the energy storage device 1 configured as shown in Figure 3 , it can be assumed that a short circuit occurs in the battery rack or a short circuit occurs in the battery module 10.

[0052] Conventionally, a fuse having a specification capable of withstanding the output voltage of the battery module is used as the module fuse to satisfy the UN / DOT 3.83 regulation. For example, in the case of a battery module that outputs a voltage of about 50 VDC to about 100 VDC, a fuse capable of withstanding a voltage of about 120 VDC to about 150 VDC is used. However, such a module fuse uses a commercial product, and the fuse used has a short circuit specification capable of passing a current of about 20 kA.

[0053] However, in the case of the module fuse conventionally used, the battery module can be protected from a module short circuit that occurs when the battery module is used or transported alone, but there is a problem that the battery module cannot be protected from a module short circuit that occurs when a plurality of battery modules are mounted on a battery rack.

[0054] Therefore, there is a need for a method of protecting the battery module not only when the battery module is used alone, but also when the battery module is mounted in the battery rack. Also, as the fuse specification increases, the volume and price also increase. Therefore, it should be considered that the energy density is not reduced due to the volume without deteriorating the price competitiveness of the battery module.

[0055] In the module fuse MF according to the present embodiment, a fuse having a voltage specification capable of corresponding to the voltage (battery rack output voltage) output from the energy storage device 1 is used. The module fuse MF can have the same specification as the voltage specification of the rack fuse RF.

[0056] When a short circuit occurs while a plurality of battery modules 10 are installed in the battery rack, the voltage applied to the module fuse MF can vary. At this time, when a short circuit occurs in the battery rack, if the uppermost module fuse MF is melted first, a voltage close to the system voltage can be applied across the module fuse MF (see Figure 5 ). For example, a voltage of about 1,000 VDC to about 1500 VDC can be applied across the module fuse MF. Therefore, the module fuse MF selects a fuse having a voltage specification capable of withstanding the system voltage, rather than a fuse having a voltage specification capable of withstanding 50 VDC to 100 VDC as the output voltage of the battery module as in the related art.

[0057] On the other hand, the module fuse MF according to the present embodiment has a lower short circuit specification than the rack fuse RF. As described above, as the fuse specification increases, the volume and price also increase. Therefore, the module fuse MF has a lower short circuit specification than the short circuit specification applied to the rack fuse RF installed in the energy storage device 1.

[0058] In a fuse, the voltage specification and the short circuit specification have a trade-off relationship with each other. That is, in the module fuse MF, a voltage specification higher than the conventional voltage specification is not selected, but the increase in price and volume is suppressed by reducing the short circuit specification.

[0059] As an additional embodiment, the module fuse MF can be configured to be cut off later than the rack fuse RF when a short circuit occurs in the battery rack. The cut-off speed of the module fuse MF and the rack fuse RF can be adjusted by appropriately selecting the composition, thickness, and length of the melting portion of the fuse. That is, when a short circuit occurs in the battery rack, the rack fuse RF is cut off before the module fuse MF, so that even if the short circuit specification of the module fuse MF is reduced, the battery module 10 can be safely protected.

[0060] Preferably, the module fuse MF can be configured to cut off only the rack fuse RF when a short circuit occurs in the battery rack. More preferably, the module fuse MF can be configured to start melting later than when the rack fuse RF is completely melted when a short circuit occurs in the battery rack. More preferably, the module fuse MF can be configured to not operate at all when a short circuit occurs in the battery rack and the rack fuse RF is cut off.

[0061] In other words, when a short circuit occurs in the battery rack, the module fuse MF does not operate at all, and only the rack fuse RF operates, thus preventing the unnecessary replacement of the module fuse MF.

[0062] Figure 4 It is shown in accordance with Figure 3 A diagram illustrating an example of a short circuit occurring in energy storage device 1. In this example, as described above, a short circuit is shown occurring in the battery rack.

[0063] like Figure 4 As shown, when the node between the frame fuse RF and the output terminal RACK(+) is short-circuited to ground, the frame fuse RF melts to interrupt the current path. Additionally, a voltage V1 corresponding to the system voltage is applied across the frame fuse RF. Because the frame fuse RF has a voltage rating capable of withstanding the system voltage, no further damage occurs even after the circuit is interrupted.

[0064] Furthermore, when a short circuit occurs in the battery rack, the module fuse MF does not operate. Since the rack fuse RF is cut off and no current flows, no load is applied to the module fuse MF, and therefore the battery module 10 remains in a safe state.

[0065] Next, we will describe the situation where the short circuit occurs on the battery module 10 side rather than the battery rack side.

[0066] When a short circuit occurs in battery module 10, module fuse MF melts to disconnect the circuit. In this case, rack fuse RF will not operate. The voltage applied to module fuse MF can vary when it melts due to a short circuit in battery module 10. Figure 3 In the example, when a short circuit occurs near the bottommost battery module 10-N, the output voltage of battery module 10 is applied across the two ends of the module fuse MF. On the other hand, in Figure 3 In the example, when a short circuit occurs near the topmost battery module 10-1, the system voltage is applied to both ends of the module fuse MF.

[0067] Figure 5 It is shown in accordance with Figure 3 A diagram illustrating another example of a short circuit occurring in the energy storage device 1. In this example, as described above, a short circuit is shown in the uppermost battery module 10-1 of the battery module 10.

[0068] like Figure 5As illustrated, when the node between the battery module 10-1 and the rack fuse RF is shorted to the ground, the module fuse MF is melted to cut off the current path. In addition, a voltage V2 close to the system voltage is applied across both ends of the module fuse MF. However, since the module fuse MF according to the embodiment of the present application has a voltage specification capable of withstanding the system voltage, no further damage occurs even after the circuit is cut off. Thus, the battery module 10 is maintained in a safe state.

[0069] As described above, the module fuse MF provided in the battery module 10 has a voltage specification equal to that of the rack fuse RF, and has a short circuit specification lower than that of the rack fuse RF. With such a configuration, not only can the case where the battery module 10 is operated alone be safely dealt with, but also a module short circuit occurring in the battery module 10 in the battery rack state can be safely dealt with.

[0070] The terms "comprise", "consist of" or "consist essentially of" as used in the above description, means that the corresponding constituent components can be present, unless otherwise specified, and should be interpreted as possibly further including other components, rather than excluding other components. Unless otherwise defined, all terms including technical or scientific terms can be interpreted as having the same meaning as commonly understood by one of ordinary skill in the art. Terms commonly used, such as those defined in a dictionary, should be interpreted in accordance with the meaning in the context of the relevant art, and unless clearly defined in the present application, they should not be interpreted as ideal or overly formal meanings.

[0071] The above description is merely an illustration of the technical idea of the present application, and those of ordinary skill in the art to which the present application pertains will be able to make various modifications and changes without departing from the essential characteristics of the present application. Therefore, the disclosed embodiments of the present application are not intended to limit the technical idea of the present application, but to explain, and the scope of the technical idea of the present application is not limited by these embodiments. The scope of protection of the present application should be interpreted by the claims, and all technical ideas within the scope equivalent thereto should be interpreted as included in the scope of the present application.

Claims

1. An energy storage device comprising: a battery rack comprising a plurality of battery modules connected in series; and a rack fuse configured to be connected in series with the plurality of battery modules and to be fused to interrupt a current path when an overcurrent occurs in the battery rack, wherein each of the plurality of battery modules comprises a plurality of battery cells connected in series and a module fuse that is fused to interrupt a current path when an overcurrent occurs in the battery module, wherein the module fuse has an allowable voltage specification higher than an output voltage of the battery rack and has an allowable current specification higher than an allowable current specification of the rack fuse, and wherein the allowable voltage specification of the module fuse is equal to the allowable voltage specification of the rack fuse.

2. The energy storage device of claim 1, wherein, When a short circuit occurs in the battery rack, the rack fuse is fused to interrupt a current path.

3. The energy storage device of claim 2, wherein, When a short circuit occurs in the battery rack, the module fuse is further fused to interrupt a current path.

4. The energy storage device of claim 3, wherein, When a short circuit occurs in the battery rack, the module fuse starts to be fused after the rack fuse is completely fused.

5. The energy storage device of claim 2, wherein, When a short circuit occurs in the battery rack and the rack fuse is fused to interrupt a current path, the module fuse is not fused and is not damaged.

6. The energy storage device of claim 1, wherein, When a short circuit occurs in a first battery module of the plurality of battery modules and a first module fuse is fused to interrupt a current path, remaining module fuses of the plurality of module fuses other than the first module fuse are not fused and are not damaged.

7. A battery module comprising: a plurality of battery cells connected in series; and a module fuse configured to be fused and to interrupt a current path when an overcurrent occurs, wherein the module fuse has an allowable voltage specification higher than an output voltage of a battery rack comprising the battery module and has an allowable current specification higher than an allowable current specification of a rack fuse configured to be fused to interrupt a current path when an overcurrent occurs in the battery rack, and wherein the allowable voltage specification of the module fuse is equal to the allowable voltage specification of the rack fuse.

8. The battery module of claim 7, wherein, When a short circuit occurs in the battery rack, the rack fuse is fused to interrupt a current path.

9. The battery module of claim 8, wherein, When a short circuit occurs in the battery rack and the rack fuse is fused to interrupt a current path, the module fuse is not fused and is not damaged.

Images