Relay control device, and battery pack and electric vehicle comprising the device

Abstract

The relay control device according to the invention is used for a relay including contacts connected between the positive terminal of a battery and a load, and a coil connected between a relay power supply terminal and ground, the relay moving the contacts to a closed position during the application of current. The relay control device includes: a coil control switch responsive to a relay opening command and a first switching signal having a voltage level equal to or higher than a first threshold voltage; and a relay holding circuit configured to store emergency power using power supplied from the battery.

Description

Technical Field

[0001] This application claims the benefit of Korean Patent Application No. 10-2021-0035516, filed with the Korean Intellectual Property Office on March 18, 2021, the disclosure of which is incorporated herein by reference in its entirety.

[0002] This disclosure relates to a technique for delaying the transition of a relay from a closed state to an open state in an emergency. Background Technology

[0003] Recently, the demand for portable electronic products such as laptops, cameras and mobile phones has increased rapidly, and with the widespread development of electric vehicles, batteries for energy storage, robots and satellites, there is a lot of research being done on rechargeable high-performance batteries.

[0004] Currently, batteries available on the market include nickel-cadmium batteries, nickel-metal hydride batteries, nickel-zinc batteries, and lithium batteries. Among them, lithium batteries have almost no memory effect or no memory effect at all, so they are more popular than nickel-based batteries because their advantages are that they can be recharged at any time when convenient, have a very low self-discharge rate, and have high energy density.

[0005] For safe use of the battery, a relay is connected between the battery and the load. A relay consists of contacts and a coil; the contacts move between a closed position and an open position via a magnetic force generated by the coil's excitation.

[0006] There are various types of relays, among which normally open (NO) relays are widely used in electric vehicles. The contacts of a NO relay only move to the closed position when the coil is energized; otherwise, the contacts remain in the open position. When the contacts are in the closed position, power is supplied from the battery to the load (e.g., the motor of an electric vehicle), and when the contacts are in the open position, the electrical connection between the battery and the load is broken.

[0007] A coil control switch used to control the energization of a coil may include a high-side switch, a low-side switch, or a combination thereof. The coil control switch toggles between an on and off state via a signal from a control circuit (e.g., a microcontroller unit (MCU)).

[0008] However, when the contacts are held in the closed position, if a fault in the control circuit (such as a power outage) causes the signal from the control circuit to the coil control switch to be lost and the coil is unintentionally stopped from being energized, the power supply from the battery to the load is cut off, resulting in a huge safety hazard. Summary of the Invention

[0009] Technical issues

[0010] This disclosure is designed to solve the above-mentioned problems, and therefore aims to provide a relay control device for delaying the transition of a relay from a closed state to an open state in the event of a fault (e.g., loss of signal from the control circuit to the coil control switch), as well as a battery pack and an electric vehicle.

[0011] These and other objects and advantages of this disclosure will be understood from the following description and will be apparent from embodiments of this disclosure. Furthermore, it will be readily understood that the objects and advantages of this disclosure can be achieved by the means set forth in the appended claims and combinations thereof.

[0012] Technical solution

[0013] According to one aspect of this disclosure, a relay control device for a relay includes a contact connected between the positive terminal of a battery and a load; and a coil connected between a relay power supply terminal and ground, wherein when the coil is energized, the contact moves to a closed position. The relay control device includes: a control circuit configured to output a first switching signal having a voltage level equal to or higher than a first threshold voltage in response to a relay energizing command; a coil control switch connected between a terminal of the coil and the relay power supply terminal or between the opposite terminal of the coil and ground, wherein the coil control switch is energized in response to the first switching signal; and a relay holding circuit configured to store emergency power using power supplied from the battery. The relay holding circuit is configured to output the first switching signal using the emergency power instead of the control circuit when the control circuit stops outputting the first switching signal.

[0014] The coil control switch may be an NPN transistor having a collector connected to the power supply of the relay, an emitter connected to the terminal of the coil, and a base connected to the control circuit.

[0015] The relay holding circuit may include: a voltage divider connected between the positive terminal of the battery and ground, configured to generate an output voltage that is a portion of the voltage across the battery divided by a predetermined ratio; a capacitor having a terminal connected to ground, wherein the emergency power is stored in the capacitor; and a first auxiliary switch connected between the voltage divider and the opposite terminal of the capacitor. When the first auxiliary switch is turned on, the capacitor is charged by the output voltage.

[0016] The first auxiliary switch may be an NPN transistor comprising a collector connected to the output node of the voltage divider, an emitter connected to the opposite terminal of the capacitor, and a base connected to the control circuit.

[0017] The control circuit can be configured to output a second switching signal having a voltage level equal to or higher than a second threshold voltage to the base of the first auxiliary switch in response to the relay activating command. When the second switching signal is output to the base of the first auxiliary switch, the first auxiliary switch is activated.

[0018] The relay holding circuit may also include a discharge resistor connected between the base and the emitter of the coil-controlled switch.

[0019] The relay holding circuit may further include a first diode, the first diode having a positive terminal connected to the control circuit and a negative terminal connected to the base of the coil control switch.

[0020] The first diode may be a light-emitting diode (LED), which outputs a light signal when the control circuit outputs the first switching signal. The first auxiliary switch may be a phototransistor, which includes a collector connected to the output node of the voltage divider, and an emitter and a base connected to the opposite terminals of the capacitor. When the light signal is received at the base of the first auxiliary switch, the first auxiliary switch is turned on.

[0021] The relay holding circuit may further include a second diode, which includes a positive terminal connected to the opposite terminal of the capacitor and a negative terminal connected to the base of the coil control switch.

[0022] The relay holding circuit may further include: a second auxiliary switch, which is a PNP transistor including an emitter connected to the opposite terminal of the capacitor, a collector connected to the base of the coil control switch, and a base connected to the control circuit; and a pull-down resistor connected between the base of the second auxiliary switch and the ground.

[0023] The control circuit can be configured to output a third switching signal to the base of the second auxiliary switch, having a voltage level equal to or higher than the third threshold voltage. When the control circuit outputs the third switching signal, the second auxiliary switch can be turned off; when the control circuit stops outputting the third switching signal, the second auxiliary switch can be turned on.

[0024] According to another aspect of this disclosure, the battery pack includes the relay control device.

[0025] An electric vehicle according to another aspect of this disclosure includes the battery pack.

[0026] Beneficial effects

[0027] According to at least one embodiment of this disclosure, the transition of a relay from a closed state to an open state can be delayed in the event of a fault (e.g., loss of signal from the control circuit to the coil control switch).

[0028] The effects of this disclosure are not limited to those described above, and those skilled in the art will clearly understand these and other effects based on the appended claims. Attached Figure Description

[0029] The accompanying drawings illustrate exemplary embodiments of the present disclosure and are used together with the detailed description of the present disclosure below to provide a further understanding of the technical aspects of the present disclosure; therefore, the present disclosure should not be construed as limited to the drawings.

[0030] Figure 1 This is a reference diagram showing a relay control device according to a first embodiment of the present disclosure.

[0031] Figure 2 This is a reference diagram showing a relay control device 100 according to a second embodiment of the present disclosure.

[0032] Figure 3 This is a reference diagram showing a relay control device according to a third embodiment of the present disclosure.

[0033] Figure 4 This is a reference diagram showing a relay control device according to a fourth embodiment of the present disclosure. Detailed Implementation

[0034] In the following, exemplary embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. Before the description, it should be understood that the terms or words used in the specification and appended claims should not be construed as limited to their general or dictionary meanings, but rather are interpreted based on the principle that the inventors are allowed to appropriately define the terms for the best interpretation, and based on the meanings and concepts corresponding to the technical aspects of the present disclosure.

[0035] Therefore, the embodiments described herein and the illustrations shown in the accompanying drawings are merely exemplary embodiments of this disclosure and are not intended to fully describe the technical aspects of this disclosure. It should be understood that various other equivalents and modifications may be made thereto when this application is filed.

[0036] Ordinal terms such as “first” and “second” are used to distinguish one element from another among various elements, but are not intended to limit these elements.

[0037] Unless the context clearly indicates otherwise, it should be understood that, when used in this specification, the term "comprising" specifies the presence of the stated element but does not exclude the presence or addition of one or more other elements. Additionally, as used herein, the term "control unit" refers to a processing unit having at least one function or operation and may be implemented individually or in combination in hardware and software.

[0038] Furthermore, as will be further understood throughout the specification, when an element is referred to as being “connected to” another element, it may be directly connected to the other element or there may be an intermediate element.

[0039] Figure 1 This is a reference diagram showing a relay control device according to a first embodiment of the present disclosure, and Figure 2 This is a reference diagram showing a relay control device 100 according to a second embodiment of the present disclosure.

[0040] See Figure 1 and Figure 2 The electric vehicle 1 includes a battery pack 10 and a load 15. The electric vehicle 1 may also include an auxiliary power supply 18.

[0041] The battery pack 10 may include a battery 20, a relay 30, and a relay control device 100.

[0042] Battery 20 is used to supply power to load 15. Battery 20 includes at least one battery cell 21. Battery cell 21 may be, for example, a lithium-ion battery cell. Battery cell 21 is not limited to a particular type and may include any battery cell capable of being repeatedly recharged.

[0043] Relay 30 is used to disconnect and close the power path between battery 20 and load 15. Relay 30 can be a normally open (NO) relay. Relay 30 includes contacts 31 and a coil 32. When coil 32 is de-energized, contact 31 moves to the open position. When coil 32 is energized, contact 31 moves to the closed position.

[0044] Coil 32 is connected between the relay power supply terminal and ground. The relay power supply terminal can be the output terminal P+ of the auxiliary power supply 18 or the positive terminal of the battery 20. For the auxiliary power supply 18, a DC voltage source such as a lead-acid battery can be used, for example. Figure 1 The auxiliary power supply 18, which is used for the output terminal P+ of the relay power supply terminal, is illustrated in the diagram. When the coil control switch 120 is turned on, the coil 32 is energized by the DC voltage supplied through the relay power supply terminal.

[0045] The relay control device 100 includes a control circuit 110, a coil control switch 120, and a relay holding circuit 131.

[0046] The coil control switch 120 is connected between one end of the coil 32 and the relay power supply terminal, or between the other end of the coil 32 and ground. An NPN transistor with a collector, emitter, and base can be used for the coil control switch 120.

[0047] Figure 1 A coil control switch 120 is shown connected between one terminal of coil 32 and a relay power supply terminal, and the coil control switch 120 may be referred to as a "high-side switch". When the coil control switch 120 is provided as a high-side switch, the collector, emitter and base of the coil control switch 120 may be connected to the relay power supply terminal, one terminal of coil 32 and control circuit 110, respectively.

[0048] Figure 2 A coil control switch 120 is shown connected between the other terminal of coil 32 and ground, and in this case, the coil control switch 120 can be referred to as a "low-side switch". When the coil control switch 120 is provided as a low-side switch, the collector, emitter and base of the coil control switch 120 can be connected to the other terminal of coil 32, ground and control circuit 110, respectively.

[0049] The control circuit 110 can be implemented in hardware and includes at least one of an application-specific integrated circuit (ASIC), a digital signal processor (DSP), a digital signal processing device (DSPD), a programmable logic device (PLD), a field-programmable gate array (FPGA), a microprocessor, or an electrical unit for performing other functions.

[0050] Control circuit 110 is configured to output a switching signal S1 to coil control switch 120 in response to a relay on command. Control circuit 110 may continue outputting switching signal S1 until a relay off command is received. Control circuit 110 stops outputting switching signal S1 in response to a relay off command. The relay on command and relay off command may be signals sent from a user input device (not shown) disposed in the electric vehicle 1. The user input device may be, for example, the ignition button of the electric vehicle 1.

[0051] The switching signal S1 can be a signal with a voltage level equal to or higher than a first threshold voltage. The first threshold voltage can be the minimum voltage required to form the base current that turns on the coil control switch 120. When the switching signal S1 is applied to the base of the coil control switch 120, the coil control switch 120 is turned on. When the coil control switch 120 is turned on, the coil 32 is energized, and the contact 31 moves to the closed position.

[0052] The relay holding circuit 131 is configured to store emergency power using power supplied from battery 20. The emergency power stored in the relay holding circuit 131 is used to delay the transition of relay 30 from a closed state to an open state. The relay holding circuit 131 includes a voltage divider 140, a capacitor 150, and an auxiliary switch 160. The relay holding circuit 131 may also include at least one of diode 180, diode 190, or discharge resistor 170.

[0053] Voltage divider 140 is connected between the positive terminal of battery 20 and ground. The negative terminal of battery 20 can be grounded. Voltage divider 140 can be a series circuit of resistor 141 having a first resistance value and resistor 142 having a second resistance value. Voltage divider 140 is configured to generate an output voltage that is a portion of the voltage across battery 20 divided by a predetermined ratio. For example, when the first resistance value is 9 times the second resistance value, 9 / 10 of the battery voltage is applied across resistor 141, and 1 / 10 of the battery voltage is applied across resistor 142. The output voltage of voltage divider 140 refers to the voltage across resistor 142.

[0054] Capacitor 150 is charged by battery 20 to store emergency power. One end of capacitor 150 is grounded, and the other end is connected to the output node 143 of voltage divider 140 via auxiliary switch 160. The output node 143 of voltage divider 140 can be the connection node of resistors 141 and 142. When the voltage of the emergency power stored in capacitor 150 is higher than a first threshold voltage, capacitor 150 outputs a switching signal S1 together with control circuit 110, or uses the emergency power stored in capacitor 150 instead of control circuit 110, until the voltage across capacitor 150 drops below the first threshold voltage.

[0055] Auxiliary switch 160 is connected between the voltage divider 140 and the other terminal of capacitor 150, and opens and closes the power path between the output node 143 of voltage divider 140 and capacitor 150. An NPN transistor with a collector, emitter, and base can be used for auxiliary switch 160. The collector, emitter, and base of auxiliary switch 160 can be connected to the output node 143 of voltage divider 140, the other terminal of capacitor 150, and control circuit 110, respectively.

[0056] Control circuit 110 is configured to output switching signal S2 to the base of auxiliary switch 160 independently of switching signal S1. Control circuit 110 can output switching signal S2 with a predetermined duty cycle (e.g., 39%) for a predetermined time in response to a relay turn-on command. Switching signal S2 is a signal having a voltage level equal to or higher than a second threshold voltage. The second threshold voltage can be the minimum voltage required to form the base current that turns on auxiliary switch 160. When switching signal S2 is applied to the base of auxiliary switch 160, auxiliary switch 160 is turned on.

[0057] Diode 180 is connected between control circuit 110 and coil control switch 120. The anode of diode 180 can be connected to control circuit 110, while the cathode of diode 180 can be connected to the base of coil control switch 120. Diode 180 serves as the transmission path for the switching signal S1 from control circuit 110 to coil control switch 120.

[0058] Diode 190 is connected between capacitor 150 and coil control switch 120. The anode of diode 190 can be connected to the other terminal of capacitor 150, while the cathode of diode 190 can be connected to the base of coil control switch 120. Diode 190 serves as the transmission path for the switching signal S1 from capacitor 150 to coil control switch 120.

[0059] Discharge resistor 170 is connected between the emitter and base of coil control switch 120. Discharge resistor 170 is provided to discharge capacitor 150. The duration of the output switching signal S1 of capacitor 150 depends on a time constant equal to the product of the voltage of capacitor 150, the resistance of discharge resistor 170, and the capacitance of capacitor 150.

[0060] Figure 3 This is a reference diagram illustrating a relay control device according to a third embodiment of the present disclosure. Although for ease of description, Figure 3 This is shown as a high-side switch (see Figure 1 The coil control switch 120 is used for the low-side switch, but the coil control switch 120 can also be used as a low-side switch (see [link]). Figure 2 ).

[0061] Except that the control circuit 110 does not output the switch signal S2, but instead outputs the switch signal S1 to store emergency power in the capacitor 150, the light-emitting diode 181 is used as diode 180, and the phototransistor 161 is used as auxiliary switch 160. The signal transmission path between the control circuit 110 and the phototransistor 161 is removed. The relay holding circuit 133 of the relay control device 100 according to the third embodiment of this disclosure is the same as that of the first embodiment. The following description is based on the differences between this embodiment and the first embodiment.

[0062] Reference Figure 3 When the control circuit 110 outputs the switch signal S1 in the same manner as in the first embodiment, the coil control switch 120 is turned on due to the switch signal S1. Simultaneously, a positive voltage of the switch signal S1 is applied across the diode 181, and a light signal 182 is output from the diode 181. When the light signal 182 is received at the base of the phototransistor 161, the phototransistor 161 is turned on. When the phototransistor 161 is turned on, a charging path is provided from the voltage divider 140 to the capacitor 150.

[0063] According to the third embodiment, the control circuit 110 outputs a switching signal S1, simultaneously energizing the coil 32 and charging the capacitor 150. As a result, the power consumption required to output the switching signal S2 can be reduced, and the circuit complexity can be decreased.

[0064] Figure 4 This is a reference diagram illustrating a relay control device according to a fourth embodiment of the present disclosure. Although for ease of description, Figure 4 This is shown as a high-side switch (see Figure 1 The coil control switch 120 is used for the low-side switch, but the coil control switch 120 can also be used as a low-side switch (see [link]). Figure 2 ).

[0065] Except that the relay holding circuit 134 is configured to output the switching signal S1 only when the switching signal S1 from the control circuit 110 experiences abnormal loss, the relay holding circuit 134, instead of the control circuit 110, is the same as that in the first embodiment. The following description will explain the differences between this embodiment and the first embodiment.

[0066] Reference Figure 4 The relay holding circuit 134 of the relay control device 100 according to the fourth embodiment further includes an auxiliary switch 201 and a pull-down resistor 202.

[0067] For the auxiliary switch 201, a PNP transistor with a collector, emitter, and base can be used. The collector, emitter, and base of the auxiliary switch 201 can be connected to the other terminal of the capacitor 150, the base of the coil control switch 120, and the control circuit 110, respectively.

[0068] The pull-down resistor 202 is connected between the base of the auxiliary switch 201 and ground.

[0069] During normal operation, control circuit 110 outputs a switching signal S3 with a voltage level equal to or higher than a third threshold voltage to the base of auxiliary switch 201. The third threshold voltage can be the minimum voltage required to interrupt the base current that turns on auxiliary switch 201. When switching signal S3 is applied to the base of auxiliary switch 201, auxiliary switch 201 is turned off.

[0070] Therefore, when the control circuit 110 normally stops outputting the switch signal S1, the capacitor 150 is electrically disconnected from the coil control switch 120 through the switch signal S3, so the relay 30 can immediately move from the closed state to the open state.

[0071] In contrast, in the event of a malfunction in the control circuit 110 (e.g., a power outage), no switching signals S1, S2, and S3 are output from the control circuit 110. In this case, a 0V voltage is applied to the base of the auxiliary switch 201, which is connected to ground via the pull-down resistor 202, and the auxiliary switch 201 is turned on. As a result, when the relay 30 is controlled to the closed state, if the output of the switching signal S1 of the control circuit 110 suddenly stops due to the malfunction of the control circuit 110, the coil 32 is temporarily kept energized by the switching signal S1 immediately output from the relay holding circuit 134, and the transition of the relay 30 from the closed state to the open state is delayed.

[0072] When the control circuit 110 normally stops outputting the switch signal S1 in response to the relay disconnect command, the relay control device 100 according to the fourth embodiment blocks the signal path from the relay holding circuit 131 to the coil control switch 120 to avoid unnecessary delay when the relay 30 changes from the closed state to the open state.

[0073] While this disclosure has been described above with respect to a limited number of embodiments and accompanying drawings, this disclosure is not limited thereto, and it will be apparent to those skilled in the art that various modifications and alterations may be made to it within the scope of the technical aspects of this disclosure and the appended claims and their equivalents.

[0074] Furthermore, without departing from the technical aspects of this disclosure, those skilled in the art can make many substitutions, modifications and changes to the disclosure described above. This disclosure is not limited to the above embodiments and drawings, and all or some embodiments can be selectively combined to allow for various modifications.

[0075] (Explanation of reference numerals in the attached image)

[0076] 1: Electric vehicles

[0077] 10: Battery Pack

[0078] 15: Load

[0079] 20: Battery

[0080] 30: Relay

[0081] 100: Relay control device

[0082] 110: Control Circuit

[0083] 120: Coil control switch

[0084] 131, 132, 133, 134: Relay holding circuit

Claims

1. A relay control device for a relay, the relay comprising contacts connected between the positive terminal of a battery and a load, and a coil connected between a power supply terminal of the relay and ground, wherein, When the coil is energized, the contact moves to the closed position, and the relay control device includes: A control circuit configured to output a first switching signal having a voltage level equal to or higher than a first threshold voltage in response to a relay on command; A coil control switch, connected between a terminal of the coil and a relay power supply terminal or between the opposite terminal of the coil and ground, wherein the coil control switch is activated in response to a first switch signal; and A relay holding circuit, configured to store emergency power using power supplied from the battery. The relay holding circuit is configured to use the emergency power instead of the control circuit to output the first switching signal when the control circuit stops outputting the first switching signal. The relay holding circuit includes: A voltage divider is connected between the positive terminal of the battery and the ground, and the voltage divider is configured to generate an output voltage that is a portion of the voltage across the two terminals of the battery divided by a predetermined ratio. A capacitor having a terminal connected to the ground, wherein the emergency power is stored in the capacitor; and A first auxiliary switch is connected between the voltage divider and the opposite terminals of the capacitor. When the first auxiliary switch is turned on, the capacitor is charged by the output voltage.

2. The relay control device according to claim 1, wherein, The coil control switch is an NPN transistor having a collector connected to a relay power supply, an emitter connected to a terminal of the coil, and a base connected to the control circuit.

3. The relay control device according to claim 2, wherein, The first threshold voltage is the minimum voltage required to generate the base current that turns on the coil control switch.

4. The relay control device according to claim 1, wherein, The first auxiliary switch is an NPN transistor comprising a collector connected to the output node of the voltage divider, an emitter connected to the opposite terminal of the capacitor, and a base connected to the control circuit.

5. The relay control device according to claim 4, wherein, The control circuit is configured to, in response to the relay activation command, output a second switching signal having a voltage level equal to or higher than the second threshold voltage to the base of the first auxiliary switch, and Specifically, when the second switch signal is output to the base of the first auxiliary switch, the first auxiliary switch is turned on.

6. The relay control device according to claim 5, wherein, The second threshold voltage is the minimum voltage required to generate the base current that turns on the first auxiliary switch.

7. The relay control device according to claim 1, wherein, The relay holding circuit also includes a discharge resistor connected between the emitter and base of the coil control switch.

8. The relay control device according to claim 1, wherein, The relay holding circuit further includes a first diode, which has a positive terminal connected to the control circuit and a negative terminal connected to the base of the coil control switch.

9. The relay control device according to claim 8, wherein, The first diode is a light-emitting diode (LED). When the control circuit outputs the first switching signal, the LED outputs a light signal. The first auxiliary switch is a phototransistor, which includes a collector connected to the output node of the voltage divider, and an emitter and a base connected to opposite terminals of the capacitor. Specifically, when the optical signal is received at the base of the first auxiliary switch, the first auxiliary switch is turned on.

10. The relay control device according to claim 1, wherein, The relay holding circuit further includes a second diode, which has a positive terminal connected to the opposite terminal of the capacitor and a negative terminal connected to the base of the coil control switch.

11. The relay control device according to claim 1, wherein, The relay holding circuit also includes: A second auxiliary switch, comprising a PNP transistor including an emitter connected to the opposite terminal of the capacitor, a collector connected to the base of the coil control switch, and a base connected to the control circuit; and A pull-down resistor is connected between the base of the second auxiliary switch and the ground. The control circuit is configured to output a third switching signal with a voltage level equal to or higher than the third threshold voltage to the base of the second auxiliary switch, and Specifically, when the control circuit outputs the third switch signal, the second auxiliary switch is turned off, and when the control circuit stops outputting the third switch signal, the second auxiliary switch is turned on.

12. The relay control device according to claim 11, wherein, The third threshold voltage is the minimum voltage required to cut off the base current that turns on the second auxiliary switch.

13. A battery pack comprising a relay control device according to any one of claims 1 to 12.

14. An electric vehicle comprising a battery pack according to claim 13.

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