Voltage switching prompting device and electric vehicle

Abstract

The utility model provides a voltage switching prompting device and an electric vehicle, and the device comprises a battery connection interface which is connected with a sodium ion battery pack and is used for obtaining an output voltage value of the sodium ion battery pack; the input end of the comparison module is connected with the battery connection interface, and the comparison module is used for determining a target voltage platform corresponding to the output voltage value and outputting a control signal corresponding to the target voltage platform through the output end of the comparison module; the control end of the control switch is connected with the output end of the comparison module, and the control switch is used for executing the on-off action corresponding to the control signal; the switch connection interfaces are led out from the two ends of the control switch and used for being arranged on a voltage switching signal transmission line so as to correspondingly control the on-off state of the voltage switching signal transmission line through the on-off state of the control switch, and the on-off state of the voltage switching signal transmission line is used for indicating different target voltage platforms.

Description

Technical Field

[0001] The present application relates to the field of voltage control technology, and in particular to a voltage switching prompt device and an electric vehicle. Background Art

[0002] In order to be compatible with different battery voltages, the controllers of current electric vehicles (including electric two-wheelers and electric three-wheelers) generally have two voltage levels, each of which corresponds to a corresponding battery voltage range. For example, the controller of an electric two-wheeler with a motor power of 1200W can match voltage platforms of 72V and 60V. That is, the 72V voltage platform is suitable for 6 lead-acid batteries with a nominal voltage of 12V, and the 60V voltage platform is suitable for 5 lead-acid batteries with a nominal voltage of 12V. Due to the low energy density and short cycle life of lead-acid batteries, the battery replacement frequency of electric vehicles is high, resulting in high costs and affecting the user experience.

[0003] Compared with ternary lithium-ion batteries and lithium iron phosphate batteries, sodium-ion batteries have the advantages of low cost, high safety, good low-temperature performance, and good fast charging performance. Compared with lead-acid batteries, they have the advantages of high energy density and long cycle life. Therefore, they are chosen as electric vehicle batteries for electric vehicles. The open circuit voltage (OCV) of sodium-ion batteries decreases as the state of charge (SOC) decreases, which in turn leads to a lower output voltage of the sodium-ion battery as the battery power is consumed. As a result, when the battery's state of charge can still support the use of the electric vehicle, the electric vehicle controller may choose to perform undervoltage protection due to the low open circuit voltage, affecting the normal use of the electric vehicle. Utility Model Content

[0004] In view of this, the purpose of the present application is to provide at least a voltage switching prompt device and an electric vehicle, which collects the output voltage value of the sodium ion battery pack installed on the electrical equipment, and uses a comparison module to compare the target voltage platform corresponding to the output voltage value, and outputs a corresponding control signal for the target voltage platform. The control end of the control switch performs an on-off action according to the received control signal. Since the control switch is set at both ends of the voltage switching signal transmission line, the on-off state of the voltage switching signal transmission line is synchronously changed to reflect the target voltage platform corresponding to the current output voltage value of the sodium ion battery pack through the on-off state of the voltage switching signal transmission line. This solves the technical problem of the high battery replacement frequency caused by the use of lead-acid batteries in the prior art, and achieves the technical effect of reducing the battery replacement frequency by using sodium ion batteries and making full use of sodium ion batteries through the voltage switching prompt device.

[0005] This application mainly includes the following aspects:

[0006] In a first aspect, an embodiment of the present application provides a voltage switching prompt device, the device comprising: a battery connection interface, connected to a sodium-ion battery pack, for obtaining the output voltage value of the sodium-ion battery pack; a comparison module, the input end of the comparison module being connected to the battery connection interface, for determining a target voltage platform corresponding to the output voltage value, and outputting a control signal corresponding to the target voltage platform through the output end of the comparison module; a control switch, the control end of the control switch being connected to the output end of the comparison module, for executing an on-off action corresponding to the control signal; a switch connection interface, led out from both ends of the control switch, for being set on a voltage switching signal transmission line, so as to control the on-off state of the voltage switching signal transmission line according to the on-off state of the control switch, and the on-off state of the voltage switching signal transmission line being used to indicate different target voltage platforms.

[0007] Optionally, the comparison module includes: a first voltage divider circuit, one end of the first voltage divider circuit serves as the input end of the comparison module, and the other end of the first voltage divider circuit is grounded; a comparator, the power supply end of the comparator is connected to the preset voltage, the ground end of the comparator is grounded, the first input end of the comparator is connected to the voltage divider end of the first voltage divider circuit, the second input end of the comparator is connected to a reference constant voltage, and the output end of the comparator serves as the output end of the comparison module, wherein the comparator determines the target voltage platform corresponding to the output voltage value based on the comparison result of the reference voltage and the voltage divider voltage of the voltage divider end of the first voltage divider circuit, and outputs a control signal corresponding to the target voltage platform accordingly.

[0008] Optionally, the target voltage platform includes a first voltage platform and a second voltage platform, the first voltage platform is greater than the second voltage platform, wherein the divided voltage corresponds to the first voltage platform when it is greater than the reference voltage, and corresponds to the second voltage platform when the divided voltage is less than or equal to the reference voltage, the control signal corresponding to the first voltage platform is one of a high-level signal and a low-level signal, and the control signal corresponding to the second voltage platform is the other of a high-level signal and a low-level signal.

[0009] Optionally, the first voltage divider circuit includes a first resistor and a second resistor, wherein one end of the first resistor serves as one end of the first voltage divider circuit, the other end of the first resistor is connected to one end of the second resistor, and the other end of the second resistor serves as the other end of the first voltage divider circuit, wherein the connection between the first resistor and the second resistor serves as the voltage divider end of the first voltage divider circuit.

[0010] Optionally, the device further includes a reference voltage module, wherein the reference voltage module includes: a step-down unit, wherein the input end of the step-down unit is connected to the battery connection interface, the output end of the step-down unit is connected to the voltage end of the comparator, the ground end of the step-down unit is grounded, and the step-down unit is used to step down the output voltage of the sodium ion battery pack to a preset voltage; a second voltage divider circuit, wherein one end of the second voltage divider circuit is connected to the output end of the step-down unit, the other end of the second voltage divider circuit is grounded, and the voltage divider end of the second voltage divider circuit is connected to the second input end of the comparator, and is used to provide the reference constant voltage to the second input end of the comparator.

[0011] Optionally, the second voltage divider circuit includes a third resistor and a fourth resistor, wherein one end of the third resistor serves as one end of the second voltage divider circuit, the other end of the fourth resistor is connected to one end of the third resistor, and the other end of the fourth resistor serves as the other end of the second voltage divider circuit, wherein the connection between the third resistor and the fourth resistor serves as the voltage divider end of the second voltage divider circuit.

[0012] Optionally, the reference voltage module also includes a first capacitor, a first diode and a second diode, wherein the first capacitor is arranged between the output end of the step-down unit and the ground end of the step-down unit, and the first diode and the second diode are connected in series and arranged between the voltage divider end of the second voltage divider circuit and the second input end of the comparator.

[0013] In a second aspect, an embodiment of the present application further provides an electric vehicle, comprising: a sodium ion battery pack, wherein the output end of the sodium ion battery pack is used to connect to the battery connection interface; a controller, wherein the voltage switching contact of the controller is connected to the voltage switching signal transmission line, and the on-off state of the voltage switching signal transmission line is determined by the voltage switching contact, and the voltage gear of the electric vehicle is controlled accordingly according to the on-off state of the voltage switching signal transmission line; a voltage switching prompt device as described in the first aspect or any possible embodiment of the first aspect.

[0014] Optionally, the on-off state includes a connected state and a disconnected state, and the voltage gear includes a first voltage gear and a second voltage gear, the first voltage gear and the second voltage gear respectively corresponding to different voltage platforms output by the sodium ion battery pack, wherein the controller is configured to: if the on-off state of the voltage switching signal transmission line is the connected state, control the voltage gear to be one of the first voltage gear and the second voltage gear; if the on-off state of the voltage switching signal transmission line is the disconnected state, control the voltage gear to be the other of the first voltage gear and the second voltage gear.

[0015] Optionally, the first voltage level and the second voltage level correspond to different undervoltage thresholds, wherein the controller is configured to: obtain the current output voltage value of the sodium-ion battery pack; and determine whether to execute the undervoltage protection strategy of the electric vehicle based on a comparison result of the undervoltage threshold corresponding to the current voltage level and the current output voltage value.

[0016] An embodiment of the present application provides a voltage switching prompt device and an electric vehicle, the device comprising: a battery connection interface connected to a sodium-ion battery pack for obtaining an output voltage value of the sodium-ion battery pack; a comparison module, wherein an input end of the comparison module is connected to the battery connection interface, for determining a target voltage platform corresponding to the output voltage value, and outputting a control signal corresponding to the target voltage platform through an output end of the comparison module; a control switch, wherein a control end of the control switch is connected to the output end of the comparison module, for executing an on-off action corresponding to the control signal; a switch connection interface, led out from both ends of the control switch, for being set on a voltage switching signal transmission line, so as to control the on-off state of the voltage switching signal transmission line correspondingly through the on-off state of the control switch, and the on-off state of the voltage switching signal transmission line is used to indicate different target voltage platforms. By collecting the output voltage value of the sodium-ion battery pack installed on the electrical equipment, and comparing the target voltage platform corresponding to the output voltage value through a comparison module, and outputting a corresponding control signal for the target voltage platform, the control end of the control switch performs an on-off action according to the received control signal. Since the control switch is arranged at both ends of the voltage switching signal transmission line, the on-off state of the voltage switching signal transmission line is synchronously changed, so that the target voltage platform corresponding to the current output voltage value of the sodium-ion battery pack is reflected by the on-off state of the voltage switching signal transmission line. This solves the technical problem of the high battery replacement frequency caused by the use of lead-acid batteries in the prior art, and achieves the technical effect of reducing the battery replacement frequency by using sodium-ion batteries and fully utilizing the sodium-ion batteries through the voltage switching prompt device.

[0017] In order to make the above-mentioned objects, features and advantages of the present application more obvious and easy to understand, preferred embodiments are given below and described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without creative work.

[0019] Figure 1A schematic structural diagram of a voltage switching prompt device provided in an embodiment of the present application is shown.

[0020] Figure 2 A circuit diagram of a voltage switching prompt device provided in an embodiment of the present application is shown. DETAILED DESCRIPTION

[0021] In order to make the purpose, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. It should be understood that the drawings in the present application only serve the purpose of illustration and description and are not used to limit the scope of protection of the present application. In addition, it should be understood that the schematic drawings are not drawn to scale. The flowcharts used in this application illustrate the operations implemented according to some embodiments of the present application. It should be understood that the operations of the flowcharts can be implemented out of sequence, and steps without logical context can be reversed or implemented simultaneously. In addition, those skilled in the art, under the guidance of the contents of this application, can add one or more other operations to the flowchart, or remove one or more operations from the flowchart.

[0022] In addition, the described embodiments are only a part of the embodiments of the present application, rather than all of the embodiments. The components of the embodiments of the present application generally described and shown in the drawings here can be arranged and designed in various configurations. Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the claimed application, but merely represents selected embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without making creative work are within the scope of protection of the present application.

[0023] In the existing technology, electric vehicles generally use ternary lithium batteries, lithium iron phosphate batteries, or lead-acid batteries. In general, ternary lithium-ion batteries have disadvantages such as poor thermal stability, high sensitivity to high temperatures, high cost, and uneven processing technology and product quality; lithium iron phosphate batteries have the disadvantage of poor low-temperature performance and are not suitable for low-temperature environments; lead-acid batteries have disadvantages such as low energy density and short cycle life, resulting in a high frequency of battery replacement in electric vehicles and high costs. Sodium-ion batteries are a type of secondary battery that uses sodium ions as charge carriers and are generally divided into three categories, namely layered transition metal oxides, polyanionic compounds, and Prussian blue compounds. They have the advantages of low cost, high safety, and suitability for low-temperature scenarios.

[0024] Furthermore, sodium-ion batteries are currently an attractive option for electric vehicles. The operating voltage of a single sodium-ion battery ranges from 2.7V to 4.2V. Multiple sodium-ion batteries can be connected in series to create different voltage platforms. Furthermore, sodium-ion batteries have a relatively flat discharge curve, combining the advantages of ternary lithium batteries, lithium iron phosphate batteries, and lead-acid batteries. Currently, electric vehicle controllers on the market generally have two voltage levels: one for 72V and the other for 60V. Electric vehicle controllers are the core control components used to control the starting, running, forward and backward movements, speed, stopping, and other electronic components of the electric vehicle's motor.

[0025] In addition, the controller generally sets an undervoltage threshold. When the output voltage of the battery reaches the undervoltage threshold, the controller will cut off the power output of the electric vehicle, instruments, lights, etc. to play the role of undervoltage protection. When the voltage gear of the controller is 72V and 60V (it can be installed on an electric vehicle that uses 6 lead-acid batteries with a nominal voltage of 12V, or it can be installed on an electric vehicle that uses 5 lead-acid batteries with a nominal voltage of 12V), if the electric vehicle is installed with 6 lead-acid batteries with a nominal voltage of 12V, the voltage gear is 72V, and the corresponding matching undervoltage threshold is set to 62V. If the electric vehicle is installed with 5 lead-acid batteries with a nominal voltage of 12V, the voltage gear is 60V, and the corresponding matching undervoltage threshold is set to 52V. Among them, since the controller is applicable to the above two voltage gears, the voltage gear of the controller can be changed accordingly for electric vehicles with different voltage platforms.

[0026] Based on this, the sodium ion battery pack provided in the embodiment of the present application is constructed by 17 sodium ion batteries connected in series to achieve a wide voltage range that meets the aforementioned two voltage levels. When the SOC of the sodium-ion battery pack is 100%, the voltage of the 17 sodium-ion batteries connected in series is about 70.38V (4.14×17), and the corresponding controller gear is 72V; when the SOC of the sodium-ion battery pack is 50%, the voltage of the sodium-ion battery pack is about 62.22V (3.66×17), at this time, it is close to the undervoltage threshold corresponding to the 72V voltage gear of the controller; when the SOC of the sodium-ion battery pack is 40%, the voltage of the sodium-ion battery pack is about 61.54V (3.62×17), at this time, it is less than the undervoltage threshold corresponding to the 72V voltage gear set by the controller. Then, according to the undervoltage protection strategy, the controller will cut off the power output of the electric vehicle, and the power supply of the instrument and lights will be cut off. For the controller, the battery pack is already in a discharged state at this time, but for the sodium-ion battery pack, more than 40% of the power is still not released, which leads to the battery pack power not being fully utilized, affecting the endurance of the electric vehicle.

[0027] Based on this, the embodiment of the present application provides a voltage switching prompt device and an electric vehicle. By collecting the output voltage value of the sodium ion battery pack installed on the electrical equipment, and comparing the target voltage platform corresponding to the output voltage value through a comparison module, and outputting a corresponding control signal for the target voltage platform, the control end of the control switch performs an on-off action corresponding to the received control signal. Since the control switch is set at both ends of the voltage switching signal transmission line, the on-off state of the voltage switching signal transmission line is synchronously changed, so that the on-off state of the voltage switching signal transmission line reflects the target voltage platform corresponding to the current output voltage value of the sodium ion battery pack. This solves the technical problem of the high battery replacement frequency caused by the use of lead-acid batteries in the prior art, and achieves the technical effect of reducing the battery replacement frequency by using sodium ion batteries and fully utilizing the sodium ion batteries through the voltage switching prompt device. The details are as follows:

[0028] See also Figure 1 , Figure 1 This is a schematic diagram of the structure of a voltage switching prompt device provided in an embodiment of the present application. Figure 1 As shown, the voltage switching prompt device provided in the embodiment of the present application includes: a battery connection interface 101, connected to a sodium ion battery pack, for obtaining the output voltage value of the sodium ion battery pack; a comparison module 102, the input end of the comparison module is connected to the battery connection interface, for determining the target voltage platform corresponding to the output voltage value, and outputting a control signal corresponding to the target voltage platform through the output end of the comparison module; a control switch S1, the control end of the control switch is connected to the output end of the comparison module, for executing the on-off action corresponding to the control signal; a switch connection interface, led out from both ends of the control switch, for being set on a voltage switching signal transmission line, so as to control the on-off state of the voltage switching signal transmission line according to the on-off state of the control switch, and the on-off state of the voltage switching signal transmission line is used to indicate different target voltage platforms.

[0029] Among them, the battery connection interface obtains the output voltage value of the sodium ion battery pack by connecting to the sodium ion battery pack, and determines the target voltage platform to which the output voltage value of the sodium ion battery pack belongs through the comparison module, and outputs a control signal corresponding to the target voltage platform.

[0030] Specifically, the control switch can perform different actions based on the control signals corresponding to different target voltage platforms, thereby changing the on / off state of the control switch. The switch connection interfaces at both ends of the control switch are used to connect to the electric vehicle controller, instructing the electric vehicle controller to switch voltage levels, thereby enabling the controller to execute the control strategy corresponding to different voltage levels.

[0031] Among them, the target voltage platform is used to indicate the voltage range of the output voltage value. The target voltage platform reflects the output voltage value of the sodium-ion battery pack and the different voltage gears of the electric vehicle.

[0032] See also Figure 2 , Figure 2 This is a circuit diagram of a voltage switching prompt device provided in an embodiment of the present application. Figure 2 As shown, the comparison module 102 in the voltage switching prompt device provided in the embodiment of the present application includes: a first voltage divider circuit, one end of the first voltage divider circuit serves as the input end of the comparison module, and the other end of the first voltage divider circuit is grounded; a comparator COMP, the power supply end of the comparator is connected to the preset voltage, the ground end of the comparator is grounded, the first input end of the comparator is connected to the voltage divider end of the first voltage divider circuit, the second input end of the comparator is connected to the reference constant voltage, and the output end of the comparator serves as the output end of the comparison module, wherein the comparator determines the target voltage platform corresponding to the output voltage value based on the comparison result of the reference voltage and the voltage divider end of the first voltage divider circuit, and outputs a control signal corresponding to the target voltage platform accordingly.

[0033] That is, the first voltage divider circuit divides the output voltage value of the collected sodium ion battery pack and then outputs it to the first input terminal of the comparator. The second input terminal of the comparator is used to receive a stable reference voltage. Then, the comparator determines the target voltage platform of the output voltage value of the sodium ion battery pack by comparing the reference voltage with the divided voltage output by the voltage divider terminal of the first voltage divider circuit. Furthermore, the reference voltage is used to distinguish different target voltage platforms. That is, the reference voltage should be set between the different divided voltage values ​​obtained by the sodium ion battery pack after voltage division by the first voltage divider circuit under different target voltage platforms.

[0034] Specifically, the target voltage platform includes a first voltage platform and a second voltage platform, the first voltage platform is greater than the second voltage platform, wherein the divided voltage corresponds to the first voltage platform when it is greater than the reference voltage, and corresponds to the second voltage platform when the divided voltage is less than or equal to the reference voltage, the control signal corresponding to the first voltage platform is one of a high-level signal and a low-level signal, and the control signal corresponding to the second voltage platform is the other of a high-level signal and a low-level signal.

[0035] That is to say, when the output voltage value of the sodium ion battery pack belongs to the first voltage platform, the output voltage value is divided by the first voltage divider circuit to obtain a divided voltage greater than the reference voltage, and then the comparator outputs a control signal; when the output voltage value of the sodium ion battery pack belongs to the second voltage platform, the output voltage value is divided by the first voltage divider circuit to obtain a divided voltage less than or equal to the reference voltage, and then the comparator outputs another control signal.

[0036] Among them, the two different control signals are distinguished by different level signals. Exemplarily, the first voltage platform is a voltage platform corresponding to 72V, and the second voltage platform is a voltage platform corresponding to 60V. Then, when the output voltage value of the sodium ion battery pack is at the voltage platform corresponding to 72V, the divided voltage is greater than the reference voltage, and the comparator outputs a high-level signal. When the output voltage value of the sodium ion battery pack is at the voltage platform corresponding to 60V, the divided voltage is less than or equal to the reference voltage, and the comparator outputs a low-level signal. Then, the high and low level signals output by the comparator indicate the target voltage platform where the current output voltage value of the sodium ion battery pack is located.

[0037] Since the controller has an undervoltage protection strategy, but the corresponding undervoltage threshold (62V) when the target voltage platform is the first voltage platform (72V) is similar to the second voltage platform (60V), in order to avoid triggering the undervoltage protection strategy corresponding to the first voltage platform when the target voltage platform is the first voltage platform, the output voltage value of the sodium ion battery pack does not reach the undervoltage threshold corresponding to the first voltage platform. Then, it is necessary to inform the controller that the current voltage platform is the second voltage platform, so as to prevent the undervoltage protection strategy from being executed before switching to the second voltage platform. Therefore, further, the reference voltage should be set to be greater than the undervoltage threshold corresponding to the first voltage platform after being divided by the first voltage divider circuit.

[0038] The on / off state of the control switch includes an on state and an off state, and the on state and the off state of the control switch correspond to different control signals. For example, when the control end of the control switch receives a high-level signal, the control switch is in the on state, and when the control end of the control switch receives a low-level signal, the control switch may be in the off state; alternatively, when the control end of the control switch receives a high-level signal, the control switch is in the off state, and when the control end of the control switch receives a low-level signal, the control switch may be in the on state.

[0039] Specifically, such as Figure 2As shown, the first voltage divider circuit includes a first resistor R1 and a second resistor R2, wherein one end of the first resistor serves as one end of the first voltage divider circuit, the other end of the first resistor is connected to one end of the second resistor, and the other end of the second resistor serves as the other end of the first voltage divider circuit, wherein the connection between the first resistor and the second resistor serves as the voltage divider end of the first voltage divider circuit.

[0040] Exemplarily, the reference voltage is set to 4V, and when the output voltage value of the sodium ion battery pack is 64V, the comparator distinguishes the target voltage platform from the first voltage platform to the second voltage platform. Furthermore, the resistance of the first resistor is 675 kilo-ohms (kΩ), and the resistance of the second resistor is 45 kilo-ohms (kΩ). When the output voltage value of the sodium ion battery pack is 72V, the voltage divider end of the first voltage divider circuit between the first resistor and the second resistor is 4.5V. When the output voltage value of the sodium ion battery pack is 64V, the voltage divider end of the first voltage divider circuit between the first resistor and the second resistor is 4V. That is to say, when the comparator determines that the divided voltage is greater than the reference voltage 4V, it is considered that the target voltage platform of the current sodium ion battery pack is the first voltage platform. When the comparator determines that the divided voltage is less than or equal to the reference voltage 4V, it is considered that the target voltage platform of the current sodium ion battery pack is the second voltage platform.

[0041] Specifically, such as Figure 2 As shown, the voltage switching prompt device also includes a reference voltage module 104, wherein the reference voltage module includes: a step-down unit U1, the input end VIN of the step-down unit is connected to the battery connection interface, the output end VOUT of the step-down unit is connected to the voltage end of the comparator, the ground end VGND of the step-down unit is grounded, and the step-down unit is used to step down the output voltage of the sodium ion battery pack to a preset voltage; a second voltage divider circuit, one end of the second voltage divider circuit is connected to the output end of the step-down unit, the other end of the second voltage divider circuit is grounded, and the voltage divider end of the second voltage divider circuit is connected to the second input end of the comparator, for providing the reference constant voltage to the second input end of the comparator.

[0042] That is, the step-down unit stably controls the output voltage value of the sodium ion battery pack at a preset voltage so as to provide electrical energy to the comparator, and the stable preset voltage provides a reference voltage to the comparator through the second voltage divider circuit so that the comparator compares the voltage values ​​corresponding to the first input terminal and the second input terminal respectively.

[0043] Specifically, the second voltage divider circuit includes a third resistor R3 and a fourth resistor R4, wherein one end of the third resistor serves as one end of the second voltage divider circuit, the other end of the fourth resistor is connected to one end of the third resistor, and the other end of the fourth resistor serves as the other end of the second voltage divider circuit, wherein the connection between the third resistor and the fourth resistor serves as the voltage divider end of the second voltage divider circuit.

[0044] For example, the step-down unit model can be SE8650X2HF, the third resistor has a resistance of 20 ohms, and the fourth resistor has a resistance of 80 ohms. The step-down unit steps down the output voltage of the sodium-ion battery pack to a preset voltage of 5V. The power supply terminal of the comparator is connected to 5V, and after voltage division by the third and fourth resistors, a 4V reference voltage is provided to the second input terminal of the comparator.

[0045] Specifically, the reference voltage module also includes a first capacitor C1, a first diode D1 and a second diode D2, wherein the first capacitor is arranged between the output end of the step-down unit and the ground end of the step-down unit, and the first diode and the second diode are connected in series and arranged between the voltage dividing end of the second voltage dividing circuit and the second input end of the comparator.

[0046] The specification of the first capacitor is set to 100 nanofarads (nF) to achieve filtering to provide a stable preset voltage to the power supply terminal of the comparator, and the first diode D1 and the second diode D2 can prevent current from flowing in the reverse direction.

[0047] Based on the same application concept, an electric vehicle corresponding to the voltage switching prompt device provided in the above embodiment is also provided in the embodiment of the present application. Since the principle of solving the problem by the electric vehicle in the embodiment of the present application is similar to that of the voltage switching prompt device in the above embodiment of the present application, the implementation of the electric vehicle can refer to the implementation of the voltage switching prompt device, and the repeated parts will not be repeated.

[0048] Specifically, an embodiment of the present application also provides an electric vehicle, which includes: a sodium ion battery pack, the output end of the sodium ion battery pack is used to connect to the battery connection interface; a controller, the voltage switching contact of the controller is connected to the voltage switching signal transmission line, the on-off state of the voltage switching signal transmission line is determined by the voltage switching contact, and the voltage gear of the electric vehicle is controlled accordingly according to the on-off state of the voltage switching signal transmission line; a voltage switching prompt device as described in any of the above embodiments.

[0049] That is, a sodium-ion battery pack is provided on the electric vehicle, and the output terminal of the sodium-ion battery pack for outputting voltage is connected to the battery connection interface of the voltage switching prompt device, so that the voltage switching prompt device can collect the output voltage value of the sodium-ion battery pack. The voltage switching contact of the controller of the electric vehicle is connected to the voltage switching signal transmission line, and the voltage switching contact of the controller determines the target voltage platform of the current sodium-ion battery pack by identifying the on-off state of the voltage switching signal transmission line. Then, the controller determines the voltage gear of the electric vehicle according to the target voltage platform, so that the controller can execute the corresponding control strategy.

[0050] The on-off state includes a connected state and a disconnected state, and the voltage gear includes a first voltage gear and a second voltage gear, and the first voltage gear and the second voltage gear respectively correspond to different voltage platforms output by the sodium ion battery pack, wherein the controller is configured to: if the on-off state of the voltage switching signal transmission line is the connected state, control the voltage gear to be one of the first voltage gear and the second voltage gear; if the on-off state of the voltage switching signal transmission line is the disconnected state, control the voltage gear to be the other of the first voltage gear and the second voltage gear.

[0051] That is to say, the voltage gear is used to measure the voltage gear of the electric vehicle, and different voltage gears correspond to the sodium ion battery pack of the electric vehicle being at different voltage platforms.

[0052] Exemplarily, the first voltage gear corresponds to the first voltage platform, and the second voltage gear corresponds to the second voltage platform. If the on-off state of the voltage switching signal transmission line is in the connected state, it is determined that the target voltage platform of the current sodium ion battery pack is one of the first voltage platform and the second voltage platform, and then, it is determined that the current voltage gear of the electric vehicle is the voltage gear corresponding to the target voltage platform in the first voltage gear and the second voltage gear; if the on-off state of the voltage switching signal transmission line is the disconnected state, it is determined that the target voltage platform of the current sodium ion battery pack is the other of the first voltage platform and the second voltage platform, and it is determined that the current voltage gear of the electric vehicle is the voltage gear corresponding to the target voltage platform in the first voltage gear and the second voltage gear.

[0053] Exemplarily, the on-off state of the voltage switching signal transmission line is the connected state, the controller identifies the voltage gear as the first voltage gear, the on-off state of the voltage switching signal transmission line is the disconnected state, and the controller identifies the voltage gear as the second voltage gear; or, the on-off state of the voltage switching signal transmission line is the disconnected state, the controller identifies the voltage gear as the first voltage gear, the on-off state of the voltage switching signal transmission line is the connected state, and the controller identifies the voltage gear as the second voltage gear.

[0054] Exemplarily, the control switch can be set as a relay. When the comparator outputs a high-level signal, the relay is in a connected state, and the voltage switching contact of the controller recognizes that the voltage switching signal transmission line is in a connected state, thereby determining that the current voltage gear of the electric vehicle is the first voltage gear; when the comparator outputs a low-level signal, the relay is in a disconnected state, and the voltage switching contact of the controller recognizes that the voltage switching signal transmission line is in a disconnected state, thereby determining that the current voltage gear of the electric vehicle is the second voltage gear.

[0055] That is, the influence of the on-off state of the control switch on the on-off state of the voltage switching signal transmission line is correspondingly set according to the recognition rule of the voltage gear pre-configured by the voltage switching contact of the controller.

[0056] Exemplarily, the controller can be set as a brushless vector controller, which indicates the voltage gear corresponding to 60V when the conversion line of the brushless vector controller is connected, and indicates the voltage gear corresponding to 72V when the conversion line is connected. Furthermore, the switch connection interface led by the control switch is used to connect the conversion line, that is, one end of the switch connection interface is connected to one end of the conversion line, and the other end of the switch connection interface is connected to the other end of the conversion line. When the control switch is closed, the current on the conversion line passes through one end of the conversion line, one end of the switch connection interface, the control switch, and the other end of the switch connection interface to the other end of the conversion line to achieve conversion line connection. When the control switch is disconnected, the current on the conversion line passes through one end of the conversion line and one end of the switch connection interface to the control switch, and does not flow through the other end of the switch connection interface and the other end of the conversion line, thereby disconnecting the conversion line. Furthermore, when the comparison module determines that the sodium ion battery pack corresponds to a target voltage platform of 72V, a control signal is sent to the control switch to disconnect the control switch, thereby disconnecting the conversion line. When the comparison module determines that the sodium ion battery pack corresponds to a target voltage platform of 60V, a control signal is sent to the control switch to close the control switch, thereby achieving conversion line connection. In this way, the brushless vector controller is informed of the voltage level corresponding to the current target voltage platform.

[0057] Exemplarily, the controller is pre-configured to determine the on / off state of the voltage switching signal transmission line according to the high level signal or low level signal received by the voltage switching contact, thereby determining the voltage gear of the electric vehicle.

[0058] That is to say, when the controller determines that the voltage gear is the first voltage gear, it executes the control strategy corresponding to the first voltage gear, and when the controller determines that the voltage gear is the second voltage gear, it executes the control strategy corresponding to the second voltage gear. The specific control strategies include under-power protection strategies, power strategies, etc., which are set according to the actual needs of the electric vehicle. The specific control strategies are not restricted in this application.

[0059] The first voltage gear and the second voltage gear correspond to different undervoltage thresholds, wherein the controller is configured to: obtain the current output voltage value of the sodium ion battery pack; and determine whether to execute the undervoltage protection strategy of the electric vehicle based on a comparison result of the undervoltage threshold corresponding to the current voltage gear and the current output voltage value.

[0060] Exemplarily, the controller collects the current output voltage value of the sodium-ion battery pack in real time, so that the controller can compare the current output voltage value with the undervoltage threshold corresponding to the current voltage level. When it is determined that the current output voltage value is less than the undervoltage threshold corresponding to the current voltage level, the under-power protection strategy of the electric vehicle is executed, such as cutting off the power output of the sodium-ion battery pack.

[0061] For example, in order to prevent the output voltage of the sodium-ion battery pack from dropping to the undervoltage threshold corresponding to the first voltage platform (72V), the undervoltage protection strategy of the first voltage gear corresponding to the first voltage platform is executed. In this way, when the output voltage of the sodium-ion battery pack is greater than the undervoltage threshold corresponding to the first voltage platform, the electric vehicle is switched to the second voltage gear corresponding to the second voltage platform (60V). Furthermore, in this application, the undervoltage protection strategy of the first voltage gear corresponding to the first voltage platform (72V) will not be executed, and the undervoltage protection strategy of the second voltage gear will only be executed after switching to the second voltage gear.

[0062] For example, the battery management system (BMS) of the sodium-ion battery pack can continuously identify the output voltage value and the cell voltage of a single sodium-ion battery. In addition, the BMS can also execute an undervoltage protection strategy based on the comparison result of the output voltage value and the undervoltage threshold of the entire battery pack, or can also execute an undervoltage protection strategy based on the comparison result of the cell voltage and the undervoltage threshold of the cell voltage. Moreover, after the battery pack is fully charged, the controller can again identify the voltage platform of the battery pack as the first voltage platform and correspondingly determine the voltage gear of the electric vehicle to be the first voltage gear.

[0063] Furthermore, this application eliminates the need to manually operate the controller to prompt the controlled voltage level switching, solving the problem of short driving range caused by the undervoltage threshold corresponding to the controller's under-power protection strategy when using sodium-ion batteries. It also enables the sodium-ion battery pack to be adapted to a wider range of electric vehicle models, increasing compatibility. Furthermore, this application does not require high-cost electronic components such as single-chip microcomputers. It can also inform the controller of the various different voltage platforms corresponding to the current resistor group by changing the resistance values ​​of each resistor in the voltage divider circuit. Switching can be achieved simply by identifying the voltage values ​​output at both ends of the battery pack, without the need to write software or programs.

[0064] Those skilled in the art can clearly understand that, for the convenience and simplicity of description, the specific working process of the system and device described above can refer to the corresponding process in the aforementioned method embodiment, and will not be repeated here. In the several embodiments provided in this application, it should be understood that the disclosed system, device and method can be implemented in other ways. The device embodiments described above are merely schematic. For example, the division of the units is only a logical function division. There may be other division methods in actual implementation. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some communication interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0065] The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed across multiple network units. Some or all of these units may be selected to achieve the purpose of this embodiment according to actual needs.

[0066] In addition, each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit.

[0067] If the functions are implemented in the form of software functional units and sold or used as independent products, they can be stored in a non-volatile computer-readable storage medium that is executable by a processor. Based on this understanding, the technical solution of the present application, or the part that contributes to the prior art, or the part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes several instructions for enabling a computer device (which can be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the method described in each embodiment of the present application. The aforementioned storage medium includes various media that can store program codes, such as a USB flash drive, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk, or an optical disk.

[0068] The above are only specific embodiments of the present application, but the scope of protection of this application is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in this application should be included in the scope of protection of this application. Therefore, the scope of protection of this application should be based on the scope of protection of the claims.

Claims

1. A voltage switching prompt device, characterized in that: The device comprises: A battery connection interface, connected to a sodium-ion battery pack, for obtaining an output voltage value of the sodium-ion battery pack; a comparison module, wherein an input terminal of the comparison module is connected to the battery connection interface, and is configured to determine a target voltage platform corresponding to the output voltage value, and output a control signal corresponding to the target voltage platform through an output terminal of the comparison module; a control switch, wherein a control end of the control switch is connected to an output end of the comparison module and is used to perform an on-off action corresponding to the control signal; A switch connection interface is led out from both ends of the control switch and is used to be set on the voltage switching signal transmission line to control the on-off state of the voltage switching signal transmission line according to the on-off state of the control switch. The on-off state of the voltage switching signal transmission line is used to indicate different target voltage platforms.

2. The device according to claim 1, characterized in that The comparison module includes: a first voltage divider circuit, one end of the first voltage divider circuit serving as an input end of the comparison module, and the other end of the first voltage divider circuit being grounded; A comparator, wherein the power supply terminal of the comparator is connected to a preset voltage, the ground terminal of the comparator is grounded, the first input terminal of the comparator is connected to the voltage divider terminal of the first voltage divider circuit, the second input terminal of the comparator is connected to a reference constant voltage, and the output terminal of the comparator serves as the output terminal of the comparison module. The comparator determines the target voltage platform corresponding to the output voltage value based on a comparison result between the reference voltage and the divided voltage at the divided voltage end of the first voltage divider circuit, and outputs a control signal corresponding to the target voltage platform.

3. The device according to claim 2, characterized in that The target voltage platform includes a first voltage platform and a second voltage platform, the first voltage platform is greater than the second voltage platform, Wherein, when the divided voltage is greater than the reference voltage, it corresponds to the first voltage platform; when the divided voltage is less than or equal to the reference voltage, it corresponds to the second voltage platform. The control signal corresponding to the first voltage platform is one of a high level signal and a low level signal, and the control signal corresponding to the second voltage platform is the other of the high level signal and the low level signal.

4. The device according to claim 2, characterized in that The first voltage divider circuit includes a first resistor and a second resistor. One end of the first resistor serves as one end of the first voltage divider circuit, the other end of the first resistor is connected to one end of the second resistor, and the other end of the second resistor serves as the other end of the first voltage divider circuit. The connection point between the first resistor and the second resistor serves as a voltage dividing end of the first voltage dividing circuit.

5. The device according to claim 2, characterized in that The device further includes a reference voltage module, wherein the reference voltage module includes: A step-down unit, wherein the input end of the step-down unit is connected to the battery connection interface, the output end of the step-down unit is connected to the voltage end of the comparator, the ground end of the step-down unit is grounded, and the step-down unit is used to step down the output voltage of the sodium ion battery pack to a preset voltage; A second voltage divider circuit, one end of the second voltage divider circuit is connected to the output end of the step-down unit, the other end of the second voltage divider circuit is grounded, and the voltage divider end of the second voltage divider circuit is connected to the second input end of the comparator, for providing the reference constant voltage to the second input end of the comparator.

6. The device according to claim 5, characterized in that The second voltage divider circuit includes a third resistor and a fourth resistor, One end of the third resistor serves as one end of the second voltage divider circuit, the other end of the fourth resistor is connected to one end of the third resistor, and the other end of the fourth resistor serves as the other end of the second voltage divider circuit. Wherein, the connection point between the third resistor and the fourth resistor serves as the voltage dividing end of the second voltage dividing circuit.

7. The device according to claim 5, characterized in that The reference voltage module further includes a first capacitor, a first diode and a second diode. The first capacitor is arranged between the output end of the step-down unit and the ground end of the step-down unit, and the first diode and the second diode are connected in series and arranged between the voltage dividing end of the second voltage dividing circuit and the second input end of the comparator.

8. An electric vehicle, characterized in that: The electric vehicle comprises: A sodium ion battery pack, wherein the output end of the sodium ion battery pack is used to connect to the battery connection interface; A controller, wherein a voltage switching contact of the controller is connected to the voltage switching signal transmission line, the on-off state of the voltage switching signal transmission line is determined by the voltage switching contact, and the voltage gear of the electric vehicle is controlled accordingly according to the on-off state of the voltage switching signal transmission line; The voltage switching prompt device according to any one of claims 1 to 7.

9. The electric vehicle according to claim 8, characterized in that: The on-off state includes a connected state and a disconnected state, and the voltage gear includes a first voltage gear and a second voltage gear, wherein the first voltage gear and the second voltage gear correspond to different voltage platforms output by the sodium ion battery pack, respectively. Wherein, the controller is configured as follows: If the on / off state of the voltage switching signal transmission line is the connected state, controlling the voltage level to be one of the first voltage level and the second voltage level; If the on-off state of the voltage switching signal transmission line is the disconnected state, the voltage level is controlled to be the other of the first voltage level and the second voltage level.

10. The electric vehicle according to claim 9, characterized in that: The first voltage level and the second voltage level correspond to different undervoltage thresholds. Wherein, the controller is configured as follows: Obtaining a current output voltage value of the sodium ion battery pack; Whether to execute the under-voltage protection strategy of the electric vehicle is determined based on a comparison result between the under-voltage threshold corresponding to the current voltage gear and the current output voltage value.

Images