Battery disconnect unit including semiconductor relay

Abstract

The present invention relates to a battery disconnect unit for delivering or disconnecting power of a battery to a load. The battery disconnect unit according to the present invention comprises: a first main relay connected between a positive terminal of a battery and a positive terminal of an inverter; a second main relay connected between a negative terminal of the battery and a negative terminal of the inverter; a pre-charge relay connected in parallel with the first main relay and configured to pre-charge a DC link capacitor connected in parallel with the inverter; and a control unit comprising one or more processors and a memory, and configured to control connection or disconnection of the first main relay, the second main relay, and the pre-charge relay, wherein the first main relay and the pre-charge relay are configured as different types of relays, thereby increasing reliability of the battery disconnect unit.

Description

Battery disconnect unit including semiconductor relay

[0001] The present invention relates to a battery disconnect unit (BDU) that connects or disconnects the power of a battery to a load, and more particularly, to a battery disconnect unit using a semiconductor relay.

[0002] In the fields of eco-friendly (electric, hydrogen, hybrid) vehicles and e-mobility, the technology to safely supply or cut off power from the battery to the motor is very important in terms of providing safety and stability.

[0003] The battery pack system for this can be composed of a BMA (Battery Module Assembly), BMU (Battery Management Unit), CMU (Cell Monitoring Unit), and BDU (Battery Disconnect Unit).

[0004] Among these, the Battery Disconnect Unit is placed between the battery and the motor inverter and serves to supply or cut off power from the battery to the motor.

[0005] Battery disconnect units have used mechanical relays to supply or cut off power, but mechanical relays have the disadvantages of having a short lifespan, generating operating noise, and being relatively large and heavy.

[0006] Additionally, if the mechanical relay is fused due to overcurrent, etc., it cannot block the overcurrent of the battery, so there is a risk of damage to the load connected to the battery, such as an inverter or motor, or even a fire.

[0007] To prevent this, a mechanical relay of the electronic fuse type was designed, which installs a sensor on the line to which the mechanical relay is connected and disconnects the mechanical relay when an overcurrent flows.

[0008] However, even if a separate sensor is added, there is still a problem that damage may occur due to overcurrent flowing during the delay time between sensing the current value to determine overcurrent and shutting off the relay.

[0009] The inventors of the present invention have dedicated research efforts to addressing the problems of battery disconnect units using mechanical relays according to the prior art. Through extensive research and development, they have developed a battery disconnect unit that utilizes both an e-fuse-type mechanical relay and a semiconductor relay, enhancing fault response and safety. This effort has led to the completion of the present invention.

[0010] An object of the present invention is to provide a battery disconnect unit having improved reliability by using an electronic relay using a semiconductor together with a mechanical relay in the battery disconnect unit.

[0011] Another object of the present invention is to provide a battery disconnect unit that is more flexible in responding to failures by using different types of relays in the battery disconnect unit.

[0012] Meanwhile, other unspecified purposes of the present invention will be additionally considered within a range that can be easily inferred from the detailed description and effects thereof below.

[0013] The battery disconnect unit according to the present invention is:

[0014] A first main relay connected between a positive electrode of a battery and a positive electrode of an inverter; a second main relay connected between a negative electrode of the battery and a negative electrode of the inverter; a precharge relay connected in parallel with the first main relay and for initially charging a DC link capacitor connected in parallel with the inverter; and a control unit including one or more processors and memories and controlling connection or opening of the first main relay, the second main relay, and the precharge relay, wherein the first main relay and the precharge relay are configured as different types of relays.

[0015] The first main relay is characterized in that it is an e-fuse relay that includes a mechanical relay and a sensor for sensing voltage or current between the battery and the inverter, and that connects or opens the mechanical relay by the control unit based on the voltage or current measured by the sensor.

[0016] The above second main relay is characterized in that it is composed of a different type of relay from the above first main relay.

[0017] If the above first main relay is a semiconductor relay,

[0018] The second main relay is characterized in that it is an e-fuse relay that includes a mechanical relay and a sensor for sensing voltage or current between the battery and the inverter, and that connects or opens the mechanical relay by the control unit based on the voltage or current measured by the sensor.

[0019] The above precharge relay is characterized by being a semiconductor relay.

[0020] The above precharge relay is characterized in that it operates as a main relay that connects the positive pole of the battery and the positive pole of the inverter when the first main relay is faulty.

[0021] It is characterized by further including a precharge resistor connected between the precharge relay and the positive pole of the inverter.

[0022] The above second main relay is characterized by a structure in which a mechanical relay and a semiconductor relay are connected in parallel.

[0023] The above semiconductor relay is characterized by a back-to-back structure in which a pair of semiconductor switches are connected in opposite current directions.

[0024] According to the present invention, by using an e-fuse mechanical relay and a semiconductor relay together in a battery disconnect unit, the stability of the battery disconnect unit can be improved.

[0025] Additionally, by using different types of relays, there is an advantage in that relay failures can be prevented from occurring simultaneously.

[0026] Meanwhile, even if the effect is not explicitly mentioned herein, it is added that the effect and its provisional effect described in the following specification expected by the technical features of the present invention are treated as described in the specification of the present invention.

[0027] FIG. 1 is a schematic structural diagram of a battery blocking unit according to a preferred embodiment of the present invention.

[0028] FIG. 2 is a schematic structural diagram of a control unit of a battery disconnect unit according to a preferred embodiment of the present invention.

[0029] FIG. 3 is a schematic structural diagram of a battery system including a battery blocking unit according to a preferred embodiment of the present invention.

[0030] FIG. 4 is a schematic structural diagram of a semiconductor relay included in a battery disconnect unit according to a preferred embodiment of the present invention.

[0031] FIG. 5 is a schematic structural diagram of a battery system including a battery blocking unit according to another preferred embodiment of the present invention.

[0032] FIG. 6 is a schematic structural diagram of a relay included in a battery disconnect unit according to another preferred embodiment of the present invention.

[0033] ※ It is to be noted that the attached drawings are provided for reference only to help understand the technical concept of the present invention, and the scope of the rights of the present invention is not limited thereby.

[0034] Hereinafter, with reference to the drawings, the configuration of the present invention, guided by various embodiments thereof, and the effects resulting from such configurations will be examined. In describing the present invention, detailed descriptions of related, well-known functions that are obvious to those skilled in the art and that may unnecessarily obscure the gist of the present invention will be omitted.

[0035] Terms such as "first" and "second" may be used to describe various components, but the components should not be limited by these terms. These terms may only be used to distinguish one component from another. For example, without departing from the scope of the present invention, a "first component" may be referred to as a "second component," and similarly, a "second component" may also be referred to as a "first component." Furthermore, singular expressions include plural expressions unless the context clearly dictates otherwise. Terms used in the embodiments of the present invention may be interpreted as having meanings commonly known to those of ordinary skill in the art, unless otherwise defined.

[0036] Hereinafter, with reference to the drawings, the configuration of the present invention guided by various embodiments of the present invention and the effects resulting from the configuration will be examined.

[0037] FIG. 1 is a schematic structural diagram of a battery blocking unit according to a preferred embodiment of the present invention.

[0038] The battery disconnect unit (10) may be configured to include a first main relay (11), a second main relay (12), a precharge relay (13), and a control unit (14).

[0039] The first main relay (11) is connected between the positive pole of the battery (5) and the positive pole of the DC-link capacitor (3) to supply or cut off power to the inverter (2).

[0040] The second main relay (12) is connected between the negative pole of the battery (5) and the negative pole of the DC-link capacitor (3) and supplies or cuts off power to the inverter (2) together with the first main relay (11).

[0041] The precharge relay (13) and the precharge resistor (16) are connected in parallel with the first main relay (11) and are used to initially charge the DC-link capacitor (3).

[0042] The precharge relay (13) supplies a voltage limited by the precharge resistor (16) to the DC-link capacitor (3) and the inverter (2) to prevent damage due to inrush current during the initial start-up of the motor (1), and after the voltage of the DC-link capacitor (3) reaches a certain voltage, it switches to an open state so that power from the battery (5) is supplied to the inverter (2) by the first main relay (11).

[0043] The control unit (14) receives instructions from the battery management unit (BMU) or controls the relays using current or voltage information measured by the sensor (15).

[0044] For this purpose, the control unit (14) may include one or more processors and memories.

[0045] FIG. 2 is a schematic structural diagram of a control unit included in a battery disconnect unit according to a preferred embodiment of the present invention.

[0046] The control unit (14) may include one or more processors (141) and memory (142).

[0047] The memory (142) may store instructions, data structures, and program codes that can be read by the processor (141). In embodiments, at least the operations performed by the processor (141) may be implemented by executing instructions or codes of the program stored in the memory.

[0048] The memory may include a flash memory type, a hard disk type, a multimedia card micro type, a card type memory (e.g., SD or XD memory, etc.), and may include a non-volatile memory including at least one of a ROM (Read-Only Memory), an EEPROM (Electrically Erasable Programmable Read-Only Memory), a PROM (Programmable Read-Only Memory), a magnetic memory, a magnetic disk, and an optical disk, and a volatile memory such as a RAM (Random Access Memory) or a SRAM (Static Random Access Memory).

[0049] The memory (142) can store one or more instructions or programs that can be used when the processor (141) controls the relays (11, 12, 13) or transmits and receives data through a communication unit (not shown).

[0050] The processor (141) controls the overall operations of the battery disconnect unit (10). For example, the processor (141) can control the overall operations of the battery disconnect unit (10), such as supplying or disconnecting power to the battery, by executing one or more commands stored in the memory (142).

[0051] The processor (141) may be configured as at least one of, for example, a central processing unit, a microprocessor, a graphic specific integrated circuits (GRAPHIC), a processing unit (PROCESSING UNIT), an ASICS (Application DSPs (Digital Signal Processors), DSPDs (Digital Signal Processing Devices), PLDs (Programmable Logic Devices), FPGAs (Field Programmable Gate Arrays), an application processor, a neural processing unit, or an artificial intelligence processor designed with a hardware structure specialized for processing an artificial intelligence model, but is not limited thereto.

[0052] FIG. 3 illustrates an example of a battery system including a battery disconnect unit according to a preferred embodiment of the present invention.

[0053] The battery system may include an inverter (2) for driving a motor (1), a battery (5) for supplying power to the motor (1), a cell monitoring unit (CMU) (6) for monitoring cells of the battery (5), a battery management unit (BMU) (4) for managing the battery system, and a battery disconnect unit (10) for managing the connection between the battery (5) and the motor (1).

[0054] The first main relay (11) and precharge relay (13) of the battery disconnect unit (10) may be composed of different types of relays.

[0055] For example, if the first main relay (11) is a mechanical relay, the precharge relay (13) may be configured as a semiconductor relay, and conversely, if the first main relay (11) is a semiconductor relay, the precharge relay (13) may be configured as a mechanical relay.

[0056] The reliability of the battery disconnect unit (10) can be improved by configuring the first main relay (11) and the precharge relay (13) with different types of relays. This is because if they are configured with the same type of relay, the probability of simultaneous failures in similar environments may also increase.

[0057] If the first main relay (11) is a mechanical relay, the first main relay (11) may be an e-fuse relay that controls connection or opening by the sensor (15) measurement value.

[0058] A typical thermal cutoff fuse is designed to break the connection when the temperature rises due to overcurrent. However, since it does not immediately cut off even when overcurrent flows, there are limitations in protecting the circuit or components.

[0059] To compensate for the shortcomings of such thermal fuses, the e-fuse senses current or voltage by a sensor (15), and when a higher voltage or current than the design flows, the control unit (14) determines this and blocks the first main relay (11) or the second main relay (12).

[0060] In the case where the first main relay (11) is a mechanical relay, the precharge relay (13) can be configured as an electronic semiconductor relay of a different type from the mechanical relay.

[0061] When the precharge relay (13) is configured as a semiconductor relay, the precharge relay (13) may be a MOSFET (Si, SiC, IGBT, etc.) for implementing a bidirectional electronic relay.

[0062] FIG. 4 is a schematic structural diagram of a semiconductor relay according to a preferred embodiment of the present invention.

[0063] Since MOSFETs have a structure that includes a diode to block current flow when switched off, in the case of semiconductor switches using MOSFETs, reverse current can flow through this diode.

[0064] To prevent this, the precharge relay (13) may be configured in a back-to-back structure in which the diodes included in the first semiconductor switch (131) and the relay (13) are arranged in a direction facing each other. Due to the diodes being in the opposite direction, when the semiconductor switches are in the off state, current cannot flow in any direction through the diodes.

[0065] According to another embodiment of the present invention, the first main relay (11) and the second main relay (12) may have a structure using different types of relays.

[0066] For example, if the first main relay (11) is a mechanical relay, the second main relay (12) may be configured as a semiconductor relay, and conversely, if the first main relay (11) is a semiconductor relay, the second main relay (12) may be configured as a mechanical relay.

[0067] At this time, as previously examined, among the first main relay (11) and the second main relay (12), the relay composed of a mechanical relay may be an e-fuse relay.

[0068] FIG. 5 is a schematic structural diagram of a battery system including a battery blocking unit according to another preferred embodiment of the present invention.

[0069] A battery disconnect unit (20) according to another embodiment of the present invention may include a first main relay (21), a second main relay (22), a precharge relay (23), and a control unit (24).

[0070] When a mechanical relay of the e-fuse type including a sensor (25) is used as the first main relay (21), the precharge relay (23) may be a semiconductor relay.

[0071] If the precharge relay (23) is a semiconductor relay, the initial inrush current can be limited by adjusting the switching cycle of the semiconductor relay without using a precharge resistor during initial charging.

[0072] Therefore, the battery blocking unit (20) according to another embodiment of the present invention may not include a precharge resistor.

[0073] If a precharge resistor is not included, the precharge relay (23), which is a semiconductor relay, can also be used as a main relay.

[0074] That is, in the case where the first main relay (21) is opened due to a failure of the first main relay (21), the precharge relay (23), which is a semiconductor relay, is used to connect the battery (5) and the inverter (2), thereby performing the role of the main relay.

[0075] In this case, the types of the precharge relay (23) connected to the positive pole of the main relay and the second main relay (22) connected to the negative pole can be different.

[0076] Figure 6 is a schematic structural diagram of a second main relay according to another preferred embodiment of the present invention.

[0077] A second main relay (22) according to another embodiment of the present invention may have a structure in which a mechanical relay (221) and a semiconductor relay (222) are connected in parallel.

[0078] The second main relay (22) can be connected to a mechanical relay (221) and a semiconductor relay (222) selectively or simultaneously under the control of the control unit (24).

[0079] In the case where the first main relay (21) is a mechanical relay or an e-fuse relay and operates as a main relay, the control unit (24) can connect the semiconductor relay (222) of the second main relay (22) to make the types of the two relays different from each other.

[0080] If the first main relay (21) is broken and the precharge relay (23), which is a semiconductor relay, operates as the main relay, the control unit (24) can operate a relay of a different type from the precharge relay (23) by connecting the mechanical relay (221) of the second main relay (22).

[0081] In this way, by changing the type of the second main relay (22) depending on the situation, the stability of the entire battery cut-off unit (20) can be further improved.

[0082] According to the battery disconnect unit according to the present invention as described above, there is an effect of increasing the reliability of the semiconductor disconnect unit by making the types of relays included in the battery disconnect unit different by using an e-fuse relay and a semiconductor relay.

[0083] The scope of protection of the present invention is not limited to the description and expression of the embodiments explicitly described above. Furthermore, it should be noted that the scope of protection of the present invention may not be limited by obvious modifications or substitutions within the technical field to which the present invention pertains.

Claims

1. A first main relay connected between the positive terminal of the battery and the positive terminal of the inverter; A second main relay connected between the negative pole of the battery and the negative pole of the inverter; A precharge relay for initially charging a DC link capacitor connected in parallel with the first main relay and connected in parallel with the inverter; and A control unit including one or more processors and memories, and controlling connection or opening of the first main relay, the second main relay, and the precharge relay; Including, but not limited to, A battery disconnect unit, characterized in that the first main relay and the precharge relay are composed of different types of relays.

2. In paragraph 1, A battery disconnect unit characterized in that the first main relay is an e-fuse relay that includes a mechanical relay and a sensor for sensing voltage or current between the battery and the inverter, and connects or opens the mechanical relay by the control unit based on the voltage or current measured by the sensor.

3. In paragraph 1, A battery disconnect unit, characterized in that the second main relay is composed of a different type of relay from the first main relay.

4. In paragraph 3, A battery disconnect unit characterized in that when the first main relay is a semiconductor relay, the second main relay is an e-fuse relay including a mechanical relay and a sensor for sensing voltage or current between the battery and the inverter, and the control unit connects or opens the mechanical relay based on the voltage or current measured by the sensor.

5. In paragraph 1, A battery disconnect unit, characterized in that the above precharge relay is a semiconductor relay.

6. In paragraph 5, A battery disconnect unit characterized in that the above precharge relay operates as a main relay connecting the positive pole of the battery and the positive pole of the inverter when the first main relay is faulty.

7. In paragraph 5, A battery disconnect unit, characterized in that it further includes a precharge resistor connected between the precharge relay and the positive electrode of the inverter.

8. In paragraph 1, A battery disconnect unit characterized in that the second main relay has a structure in which a mechanical relay and a semiconductor relay are connected in parallel.

9. In paragraph 5, The above semiconductor relay is a battery cut-off unit characterized by a back-to-back structure in which a pair of semiconductor switches are connected in opposite current directions.

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