Sodium ion battery temperature acquisition circuit and battery management system

Abstract

The utility model provides a sodium ion battery temperature acquisition circuit. The sodium ion battery temperature acquisition circuit comprises a microcontroller, a high temperature detection circuit and a low temperature detection circuit. The low-temperature detection circuit comprises a first current-limiting resistor, a first negative temperature coefficient resistor, a low-temperature circuit sampling resistor and a first electronic switching tube, and the high-temperature detection circuit comprises a second current-limiting resistor, a second negative temperature coefficient resistor, a high-temperature circuit sampling resistor and a second electronic switching tube. The microcontroller controls the low-temperature detection enable signal end and the high-temperature detection enable signal end to output level signals and obtains the voltage value of the sampling resistor through the corresponding voltage signal acquisition end. According to the actual environment temperature, the microcontroller can control on and off of the two electronic switch tubes respectively, so that it is ensured that only the low-temperature detection circuit or the high-temperature detection circuit works independently within the same time, collected voltage values are converted into corresponding temperature parameters through the microcontroller, and then data deviation and confusion are avoided.

Description

Technical Field

[0001] The present disclosure relates to the technical field of battery temperature acquisition, and in particular to a sodium ion battery temperature acquisition circuit and a battery management system. Background Art

[0002] As an emerging energy storage technology, sodium-ion batteries (Na-ion batteries) have become a research hotspot due to their abundant raw material resources, low cost, superior safety, wide operating temperature range, and high charge and discharge rates. Compared to lithium-ion batteries, Na-ion batteries show greater potential for handling extreme temperature environments and large-scale energy storage applications. However, due to the large size and large number of cells in Na-ion batteries, precise temperature management is crucial to ensure their safe and efficient operation.

[0003] Existing temperature acquisition solutions for sodium-ion batteries with energy storage often use the temperature detection pins built into the analog front end, or combine a voltage reference source with a negative temperature coefficient (NTC) thermistor (NTC) to acquire voltage. While simple and feasible, these methods have numerous limitations in practical applications. For example, the limited number of temperature detection pins built into the analog front end makes it difficult to meet the multiple temperature detection points required by large battery modules. Furthermore, solutions based on NTC thermistors (NTCs) experience significant variations in their resistance value under extreme high and low temperature environments, leading to a decrease in temperature detection accuracy and the potential for significant errors. Utility Model Content

[0004] The purpose of the present disclosure is to overcome the deficiencies in the prior art and provide a sodium ion battery temperature acquisition circuit and a battery management system that can operate in high or low temperature environments.

[0005] The purpose of this disclosure is achieved through the following technical solutions:

[0006] A sodium ion battery temperature acquisition circuit comprises a microcontroller, a high temperature detection circuit and a low temperature detection circuit.

[0007] The low-temperature detection circuit includes a first current limiting resistor, a first negative temperature coefficient resistor, a low-temperature circuit sampling resistor and a first electronic switching tube. The first end of the first electronic switching tube is used to be connected to the power supply end, the second end of the first electronic switching tube is connected to the first end of the first negative temperature coefficient resistor, the control end of the first electronic switching tube is connected to the first end of the first current limiting resistor, the second end of the first negative temperature coefficient resistor is grounded, the second end of the first current limiting resistor is connected to the low-temperature detection enable signal end of the microcontroller, the first end of the low-temperature circuit sampling resistor is connected to the first end of the first negative temperature coefficient resistor, and the second end of the low-temperature circuit sampling resistor is connected to the low-temperature voltage signal acquisition end of the microcontroller.

[0008] The high-temperature detection circuit includes a second current-limiting resistor, a second negative temperature coefficient resistor, a high-temperature circuit sampling resistor, and a second electronic switch tube. The first end of the second electronic switch tube is used to connect to the power supply terminal. The second end of the second electronic switch tube is connected to the first end of the second negative temperature coefficient resistor. The control end of the second electronic switch tube is connected to the first end of the second current-limiting resistor. The second end of the second negative temperature coefficient resistor is grounded. The second end of the second current-limiting resistor is connected to the high-temperature detection enable signal terminal of the microcontroller. The first end of the high-temperature circuit sampling resistor is connected to the first end of the second negative temperature coefficient resistor. The second end of the high-temperature circuit sampling resistor is connected to the high-temperature voltage signal acquisition terminal of the microcontroller.

[0009] The microcontroller is used to control the output of level signals at the low-temperature detection enable signal terminal and the high-temperature detection enable signal terminal, and obtain the voltage values of the low-temperature circuit sampling resistor and the high-temperature circuit sampling resistor through the low-temperature voltage signal acquisition terminal and the high-temperature voltage signal acquisition terminal.

[0010] In one embodiment, the low-temperature detection circuit further includes a first voltage-dividing resistor. The first end of the first voltage-dividing resistor is used to connect to the power supply terminal. The second end of the first voltage-dividing resistor is connected to the first end of the first electronic switch tube.

[0011] In one embodiment, the low-temperature detection circuit further includes a first biasing resistor. The first end of the first biasing resistor is connected to the control end of the first electronic switch tube. The second end of the first biasing resistor is grounded.

[0012] In one embodiment, the high-temperature detection circuit further includes a second voltage-dividing resistor. The first end of the second voltage-dividing resistor is used to connect to the power supply terminal. The second end of the second voltage-dividing resistor is connected to the first end of the second electronic switch tube.

[0013] In one embodiment, the low-temperature detection circuit further includes a second biasing resistor. The first end of the second biasing resistor is connected to the control end of the second electronic switch tube. The second end of the second biasing resistor is grounded.

[0014] In one embodiment, the resistance value of the low-temperature circuit sampling resistor is 100 K ohms, and the resistance value of the high-temperature circuit sampling resistor is 10 K ohms.

[0015] In one embodiment, the first electronic switch tube is an N-channel MOS tube.

[0016] In one embodiment, the second electronic switch tube is an N-channel MOS tube.

[0017] In one embodiment, at least one of the first current-limiting resistor and the second current-limiting resistor is a variable resistor.

[0018] A battery management system includes the sodium-ion battery temperature acquisition circuit as described in any one of the above.

[0019] Compared with the prior art, the present disclosure has at least the following advantages:

[0020] 1. For the above-mentioned sodium-ion battery temperature acquisition circuit, the microcontroller can respectively control the high-temperature detection enable signal terminal and the low-temperature detection enable signal terminal to output level signals to the first electronic switch tube and the second electronic switch tube according to the actual ambient temperature of the battery, so that one of the first electronic switch tube and the second electronic switch tube is in the conduction state, and the other electronic switch tube is in the cut-off state, enabling the sodium-ion battery temperature acquisition circuit to only enable the low-temperature or high-temperature detection circuit to work alone at the same time, thereby avoiding the problem that the microcontroller collects data with deviation due to enabling the low-temperature and high-temperature detection circuits simultaneously, and further ensuring the normal operation of the sodium-ion battery temperature acquisition circuit and preventing the collected data from being confused.

[0021] 2. Further, since the resistance value of the negative temperature coefficient resistor changes significantly with temperature in a low-temperature environment and changes relatively little with temperature in a high-temperature environment, the resistance value of the low-temperature circuit sampling resistor is higher than that of the high-temperature circuit sampling resistor, so that the voltage change range that the microcontroller can collect is more significant, and thus the actual temperature change can be accurately detected and reflected.

[0022] 3. Even further, the sodium-ion battery temperature acquisition circuit can be designed with multiple temperature detection circuits to meet the requirements of multiple temperature detection points in a large battery module, thereby improving the accuracy and applicability of the sodium-ion battery temperature acquisition circuit. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] To more clearly illustrate the technical solutions of the embodiments of the present disclosure, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present disclosure, and thus should not be regarded as limiting the scope. For those of ordinary skill in the art, other related drawings can be obtained based on these drawings without creative efforts.

[0024] Figure 1 It is a circuit diagram of the sodium-ion battery temperature acquisition circuit for an embodiment. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0025] To facilitate the understanding of the present disclosure, the present disclosure will be described more comprehensively below with reference to the relevant accompanying drawings. Preferred embodiments of the present disclosure are shown in the drawings. However, the present disclosure can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, these embodiments are provided so that the disclosure of the present disclosure can be understood more thoroughly and comprehensively.

[0026] It should be noted that when an element is referred to as being "fixed to" another element, it can be directly on the other element or there can also be an intermediate element. When an element is considered to be "connected" to another element, it can be directly connected to the other element or there may be an intermediate element at the same time. The terms "vertical", "horizontal", "left", "right" and similar expressions used herein are for illustrative purposes only and do not represent the only embodiments.

[0027] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present disclosure belongs. The terms used in the specification of the present disclosure herein are only for the purpose of describing specific embodiments and are not intended to limit the present disclosure. The term "and / or" used herein includes any and all combinations of one or more of the related listed items.

[0028] To better understand the technical solutions and beneficial effects of the present disclosure, the present disclosure will be further described in detail below with specific embodiments:

[0029] As Figure 1 shown, the temperature acquisition circuit 10 of a sodium-ion battery according to an embodiment of the present disclosure includes a microcontroller, a high-temperature detection circuit and a low-temperature detection circuit.

[0030] The low-temperature detection circuit includes a first current-limiting resistor R2, a first negative temperature coefficient resistor RT1, a low-temperature circuit sampling resistor R4 and a first electronic switch tube M1. The first end of the first electronic switch tube M1 is used to connect to the power supply terminal. The second end of the first electronic switch tube M1 is connected to the first end of the first negative temperature coefficient resistor RT1. The control end of the first electronic switch tube M1 is connected to the first end of the first current-limiting resistor R2. The second end of the first negative temperature coefficient resistor RT1 is grounded. The second end of the first current-limiting resistor R2 is connected to the low-temperature detection enable signal terminal EN_Temp_L of the microcontroller. The first end of the low-temperature circuit sampling resistor R4 is connected to the first end of the first negative temperature coefficient resistor RT1. The second end of the low-temperature circuit sampling resistor R4 is connected to the low-temperature voltage signal acquisition terminal Temp_L of the microcontroller.

[0031] The high-temperature detection circuit includes a second current-limiting resistor R6, a second negative temperature coefficient resistor RT2, a high-temperature circuit sampling resistor R8, and a second electronic switch tube M2. The first end of the second electronic switch tube M2 is used to connect to the power supply terminal. The second end of the second electronic switch tube M2 is connected to the first end of the second negative temperature coefficient resistor RT2. The control end of the second electronic switch tube M2 is connected to the first end of the second current-limiting resistor R6. The second end of the second negative temperature coefficient resistor RT2 is grounded. The second end of the second current-limiting resistor R6 is connected to the high-temperature detection enable signal terminal EN_Temp_H of the microcontroller. The first end of the high-temperature circuit sampling resistor R8 is connected to the first end of the second negative temperature coefficient resistor RT2. The second end of the high-temperature circuit sampling resistor R8 is connected to the high-temperature voltage signal acquisition terminal Temp_H of the microcontroller.

[0032] The microcontroller is used to control the output level signals of the low-temperature detection enable signal terminal EN_Temp_L and the high-temperature detection enable signal terminal EN_Temp_H, and obtain the voltage values of the low-temperature circuit sampling resistor R4 and the high-temperature circuit sampling resistor R8 through the low-temperature voltage signal acquisition terminal Temp_L and the high-temperature voltage signal acquisition terminal Temp_H.

[0033] In this embodiment, when the sodium-ion battery starts to work, the microcontroller needs to obtain the temperature information of the battery and judge the current temperature range of the battery through a preset temperature threshold. If the microcontroller judges that the battery temperature is in the low-temperature region, the microcontroller controls the low-temperature detection enable signal terminal EN_Temp_L to output a high-level signal. The high-level signal flows through the first current-limiting resistor R2 to the control end of the first electronic switch tube M1, making the voltage at the control end of the first electronic switch tube M1 greater than its threshold voltage, so that the first electronic switch tube M1 is turned on. At the same time, the high-temperature detection enable signal terminal EN_Temp_H outputs a low-level signal. The low-level signal flows through the second current-limiting resistor R6 to the control end of the second electronic switch tube M2, making the voltage at the control end of the second electronic switch tube M2 less than its threshold voltage, so that the second electronic switch tube M2 is turned off, thereby allowing the reference voltage to form a loop through the first current-limiting resistor R2, the first electronic switch tube M1, and the first negative temperature coefficient resistor RT1.

[0034] Since the low-temperature circuit sampling resistor R4 is in parallel with the first negative temperature coefficient resistor RT1, and the characteristic of the first negative temperature coefficient resistor RT1 is that its resistance value will change with temperature, the voltage of the low-temperature circuit sampling resistor R4 will change with the resistance value of the first negative temperature coefficient resistor RT1, so that the voltage of the low-temperature circuit sampling resistor R4 is obtained by the microcontroller through the low-temperature voltage signal acquisition terminal Temp_L, and further the microcontroller calculates the actual low-temperature value through a preset algorithm based on the acquired voltage value.

[0035] Further, if the microcontroller determines that the battery temperature is in the high-temperature region, the microcontroller controls the high-temperature detection enable signal terminal EN_Temp_H to output a high-level signal. The high-level signal flows through the second current-limiting resistor R6 to the control terminal of the second electronic switch M2, making the voltage at the control terminal of the second electronic switch M2 greater than its threshold voltage, so that the second electronic switch M2 is turned on. At the same time, the low-temperature detection enable signal terminal EN_Temp_L outputs a low-level signal. The low-level signal flows through the first current-limiting resistor R2 to the control terminal of the first electronic switch M1, making the voltage at the control terminal of the first electronic switch M1 less than its threshold voltage, so that the first electronic switch M1 is turned off, thereby allowing the reference voltage to form a loop through the second current-limiting resistor R6, the second electronic switch M2, and the second negative temperature coefficient resistor RT2.

[0036] Since the high-temperature circuit sampling resistor R8 is in parallel with the second negative temperature coefficient resistor RT2, and the characteristic of the second negative temperature coefficient resistor RT2 is that its resistance value will change with temperature, the voltage of the high-temperature circuit sampling resistor R8 will change with the resistance value of the second negative temperature coefficient resistor RT2. Thus, the voltage of the high-temperature circuit sampling resistor R8 is acquired by the microcontroller through the high-temperature voltage signal acquisition terminal Temp_H, and further, the microcontroller calculates the actual high-temperature value through a preset algorithm based on the acquired voltage value. Furthermore, the sodium-ion battery temperature acquisition circuit 10 can also design multiple different temperature detection circuits according to the actual needs of users to meet the requirements of large battery modules for multiple temperature detection points, thereby realizing more comprehensive monitoring of the battery temperature.

[0037] Specifically, since the negative temperature coefficient resistor is composed of metal oxide materials, the carrier concentration of its materials is low in a low-temperature environment, so that its resistance value is high. A small increase in the environmental temperature can cause a significant change in the carrier concentration, which in turn leads to a large fluctuation in the resistance value of the negative temperature coefficient resistor. On the contrary, the carrier concentration of its materials is high in a high-temperature environment, so that its resistance value is low. A small decrease in the environmental temperature is difficult to cause a significant change in the carrier concentration, which in turn leads to a small fluctuation in the resistance value of the negative temperature coefficient resistor. Therefore, the low-temperature circuit sampling resistor R4 connected in series with the first negative temperature coefficient resistor RT1 in the low-temperature detection circuit needs to be selected as a resistor with a relatively larger resistance value than the high-temperature circuit sampling resistor R8, so as to obtain a larger voltage change at low temperature; the high-temperature circuit sampling resistor R8 connected in series with the second negative temperature coefficient resistor RT2 in the high-temperature detection circuit needs to be selected as a resistor with a relatively smaller resistance value than the low-temperature circuit sampling resistor R4, so as to maintain an appropriate voltage change range at high temperature, thereby accurately detecting the actual temperature.

[0038] For the above-mentioned sodium-ion battery temperature acquisition circuit 10, the microcontroller can respectively control the high-temperature detection enable signal terminal EN_Temp_H and the low-temperature detection enable signal terminal EN_Temp_L to output level signals to the first electronic switch tube M1 and the second electronic switch tube M2 according to the actual ambient temperature of the battery, so that one of the first electronic switch tube M1 and the second electronic switch tube M2 is in the conducting state, and the other electronic switch tube is in the cut-off state, enabling the sodium-ion battery temperature acquisition circuit 10 to only enable the low-temperature or high-temperature detection circuit to work independently at the same time, thus avoiding the problem of data acquisition deviation of the microcontroller caused by enabling the low-temperature and high-temperature detection circuits simultaneously, and further ensuring the normal operation of the sodium-ion battery temperature acquisition circuit 10 and preventing the acquisition data from being confused. Further, since the resistance value of the negative temperature coefficient resistor changes significantly with temperature in a low-temperature environment and changes relatively little with temperature in a high-temperature environment, the resistance value of the low-temperature circuit sampling resistor R4 is higher than that of the high-temperature circuit sampling resistor R8, so that the voltage change range that the microcontroller can collect is more significant, and thus the actual temperature change can be accurately detected and reflected. In addition, the sodium-ion battery temperature acquisition circuit 10 can be designed with multiple temperature detection circuits to meet the requirements of multiple temperature detection points in a large battery module, thereby improving the accuracy and applicability of the sodium-ion battery temperature acquisition circuit 10.

[0039] As Figure 1 shown, in one of the embodiments, the low-temperature detection circuit further includes a first voltage-dividing resistor R1. The first end of the first voltage-dividing resistor R1 is used to connect to the power supply terminal, and the second end of the first voltage-dividing resistor R1 is connected to the first end of the first electronic switch tube M1. In this embodiment, when the voltage of the power supply terminal fluctuates, since the first voltage-dividing resistor R1 is connected in series with the first electronic switch tube M1 and divides the voltage of the power supply terminal, the first voltage-dividing resistor R1 can effectively protect the first electronic switch tube M1 from damage caused by voltage mutation, thus ensuring that the first electronic switch tube M1 maintains a stable working state. In addition, the first voltage-dividing resistor R1 also plays a role in current limiting. During the start-up or transient process of the circuit, a large current impact may occur at the power supply terminal. The first voltage-dividing resistor R1 can limit the impact current to prevent the first electronic switch tube M1 from being damaged by excessive current, thereby improving the stability of the low-temperature detection circuit.

[0040] As Figure 1As shown, in one embodiment, the low-temperature detection circuit further includes a first bias resistor R3. The first end of the first bias resistor R3 is connected to the control end of the first electronic switch tube M1, and the second end of the first bias resistor R3 is grounded. In this embodiment, the first bias resistor R3 can provide a stable bias voltage for the control end of the first electronic switch tube M1, which is beneficial to reducing the influence of external interference on the state of the switch tube, so as to ensure that the first electronic switch tube M1 can work stably under the action of the high-level signal output by the microcontroller. Secondly, when the enable signal output by the microcontroller is at a high level, the current passes through the first current-limiting resistor R2 and then through the first bias resistor R3, so that the first bias resistor R3 plays a role in voltage division and protection, thereby reducing the voltage at the control end of the first electronic switch tube M1, and further avoiding damage to the control end of the first electronic switch tube M1 due to excessive voltage.

[0041] As Figure 1 shown, in one embodiment, the high-temperature detection circuit further includes a second voltage-dividing resistor R5. The first end of the second voltage-dividing resistor R5 is used to be connected to the power supply terminal, and the second end of the second voltage-dividing resistor R5 is connected to the first end of the second electronic switch tube M2. In this embodiment, when the voltage of the power supply terminal is unstable, since the second voltage-dividing resistor R5 is connected in series with the second electronic switch tube M2 and divides the voltage of the power supply terminal, the second voltage-dividing resistor R5 can effectively protect the second electronic switch tube M2 from the damage caused by voltage mutation, so as to ensure that the second electronic switch tube M2 maintains a stable working state. In addition, the second voltage-dividing resistor R5 also plays a role in current limiting. During the startup or transient process of the circuit, a large current impact may occur at the power supply terminal. The second voltage-dividing resistor R5 can limit the impact current to prevent damage to the second electronic switch tube M2 due to excessive current, thereby improving the stability of the high-temperature detection circuit.

[0042] As Figure 1 shown, in one embodiment, the low-temperature detection circuit further includes a second bias resistor R7. The first end of the second bias resistor R7 is connected to the control end of the second electronic switch tube M2, and the second end of the second bias resistor R7 is grounded. In this embodiment, the second bias resistor R7 can provide a stable bias voltage for the control end of the second electronic switch tube M2, which is beneficial to reducing the influence of external interference on the state of the switch tube, so as to ensure that the second electronic switch tube M2 can work stably under the action of the high-level signal output by the microcontroller. Secondly, when the enable signal output by the microcontroller is at a high level, the current passes through the second current-limiting resistor R6 and then through the second bias resistor R7, so that the second bias resistor R7 plays a role in voltage division and protection, thereby reducing the voltage at the control end of the second electronic switch tube M2, and further avoiding damage to the control end of the second electronic switch tube M2 due to excessive voltage.

[0043] AsFigure 1 As shown, in one embodiment, the resistance value of the low-temperature circuit sampling resistor R4 is 100 K ohms, and the resistance value of the high-temperature circuit sampling resistor R8 is 10 K ohms. In this embodiment, since the resistance value of the negative temperature coefficient resistor fluctuates greatly with temperature in a low-temperature environment, in the low-temperature detection circuit, the low-temperature circuit sampling resistor R4 selects a 100 K ohm resistor in series with the first negative temperature coefficient resistor RT1. So that in a low-temperature environment, when the resistance value of the first negative temperature coefficient resistor RT1 changes significantly due to a small increase in the ambient temperature, the low-temperature circuit sampling resistor R4 can provide sufficient voltage division, so that the voltage change range that the microcontroller can collect is more significant, and then it can accurately detect and reflect the actual temperature change. Similarly, in the high-temperature detection circuit, the high-temperature circuit sampling resistor R8 selects 10 K ohms in series with the second negative temperature coefficient resistor RT2. Since in a high-temperature environment, the resistance value of the second negative temperature coefficient resistor RT2 changes relatively little with temperature, only changing by a few hundred ohms per 1 °C change, so a high-temperature circuit sampling resistor R8 with a smaller resistance value is selected, which is beneficial to maintaining an appropriate voltage change range at high temperature, and then enables the microcontroller to more accurately detect and reflect the actual temperature.

[0044] As Figure 1 As shown, in one embodiment, the first electronic switch tube M1 is an N-channel MOS tube. In this embodiment, the first end of the first electronic switch tube M1 is the drain of the N-channel MOS tube, the second end of the first electronic switch tube M1 is the source of the N-channel MOS tube, and the control end of the first electronic switch tube M1 is the gate of the N-channel MOS tube. Its main function in the low-temperature detection circuit is to control the on and off of the current loop. When the microcontroller needs to obtain the resistance value of the low-temperature circuit sampling resistor R4, a high-level signal is output to the gate of the first electronic switch tube M1 through the low-temperature detection enable signal terminal EN_Temp_L, so that the gate voltage is greater than its threshold voltage, thereby making the first electronic switch tube M1 conduct. The current output by the power supply terminal can pass through the first voltage dividing resistor R1, the first electronic switch tube M1 and the first negative temperature coefficient resistor RT1, and form a complete current loop with the ground terminal. At this time, since the low-temperature circuit sampling resistor R4 is connected to the first negative temperature coefficient resistor RT1, the current can pass through the low-temperature circuit sampling resistor R4, and then the low-temperature voltage signal acquisition terminal Temp_L can obtain the measured voltage value through the low-temperature circuit sampling resistor R4.

[0045] As Figure 1As shown, in one embodiment, the second electronic switch tube M2 is an N-channel MOS tube. In this embodiment, the first end of the second electronic switch tube M2 is the drain of the N-channel MOS tube, the second end of the second electronic switch tube M2 is the source of the N-channel MOS tube, and the control end of the second electronic switch tube M2 is the gate of the N-channel MOS tube. Its main function in the high-temperature detection circuit is to control the on / off of the current loop. When the microcontroller needs to obtain the resistance value of the high-temperature circuit sampling resistor R8, a high-level signal is output to the gate of the second electronic switch tube M2 through the high-temperature detection enable signal terminal EN_Temp_H, so that the gate voltage is greater than its threshold voltage, thereby causing the second electronic switch tube M2 to conduct. The current output by the power supply terminal can pass through the second voltage-dividing resistor R5, the second electronic switch tube M2, and the second negative temperature coefficient resistor RT2, and form a complete current loop with the ground terminal. At this time, since the high-temperature circuit sampling resistor R8 is connected to the second negative temperature coefficient resistor RT2, the current can pass through the high-temperature circuit sampling resistor R8, and further enable the high-temperature voltage signal acquisition terminal Temp_H to obtain the measured voltage value through the high-temperature circuit sampling resistor R8.

[0046] As Figure 1 shown, in one embodiment, at least one of the first current-limiting resistor R2 and the second current-limiting resistor R6 is a variable resistor. In this embodiment, the first current-limiting resistor R2 and the second current-limiting resistor R6 are used as variable resistors, and their main function is to adjust the magnitudes of the currents flowing into the control ends of the first electronic switch tube M1 and the second electronic switch tube M2, respectively. Therefore, by using the first current-limiting resistor R2 and the second current-limiting resistor R6 as variable resistors, the magnitudes of the control-end currents of the first electronic switch tube M1 and the second electronic switch tube M2 can be accurately adjusted according to the actual circuit requirements. Specifically, when the microcontroller outputs a high-level signal to control the first electronic switch tube M1 and the second electronic switch tube M2 to conduct, the adjustable resistor can limit the current intensity of the high-level signal, thereby ensuring the stable and normal operation of the first electronic switch tube M1 and the second electronic switch tube M2, and further improving the stability of the sodium-ion battery temperature acquisition circuit 10.

[0047] A battery management system includes a sodium-ion battery temperature acquisition circuit 10 as described in any one of the above. In this embodiment, when the sodium-ion battery starts to work, the microcontroller needs to obtain the temperature information of the battery and determine the current temperature range of the battery through a preset temperature threshold. If the microcontroller determines that the battery temperature is in the low-temperature region, the microcontroller controls the low-temperature detection enable signal terminal EN_Temp_L to output a high-level signal. The high-level signal flows through the first current-limiting resistor R2 to the control terminal of the first electronic switch tube M1, so that the voltage at the control terminal of the first electronic switch tube M1 is greater than its threshold voltage, enabling the first electronic switch tube M1 to conduct. At the same time, the high-temperature detection enable signal terminal EN_Temp_H outputs a low-level signal. The low-level signal flows through the second current-limiting resistor R6 to the control terminal of the second electronic switch tube M2, so that the voltage at the control terminal of the second electronic switch tube M2 is less than its threshold voltage, enabling the second electronic switch tube M2 to cut off. Thus, it allows the reference voltage to form a loop through the first current-limiting resistor R2, the first electronic switch tube M1, and the first negative temperature coefficient resistor RT1. Since the low-temperature circuit sampling resistor R4 is in parallel with the first negative temperature coefficient resistor RT1, and the characteristic of the first negative temperature coefficient resistor RT1 is that its resistance value will change with temperature, the voltage of the low-temperature circuit sampling resistor R4 will change with the resistance value of the first negative temperature coefficient resistor RT1. As a result, the voltage of the low-temperature circuit sampling resistor R4 is obtained by the microcontroller through the low-temperature voltage signal acquisition terminal Temp_L, and further enables the microcontroller to calculate the actual low-temperature value through a preset algorithm based on the acquired voltage value. Further, if the microcontroller determines that the battery temperature is in the high-temperature region, the microcontroller controls the high-temperature detection enable signal terminal EN_Temp_H to output a high-level signal. The high-level signal flows through the second current-limiting resistor R6 to the control terminal of the second electronic switch tube M2, so that the voltage at the control terminal of the second electronic switch tube M2 is greater than its threshold voltage, enabling the second electronic switch tube M2 to conduct. At the same time, the low-temperature detection enable signal terminal EN_Temp_L outputs a low-level signal. The low-level signal flows through the first current-limiting resistor R2 to the control terminal of the first electronic switch tube M1, so that the voltage at the control terminal of the first electronic switch tube M1 is less than its threshold voltage, enabling the first electronic switch tube M1 to cut off. Thus, it allows the reference voltage to form a loop through the second current-limiting resistor R6, the second electronic switch tube M2, and the second negative temperature coefficient resistor RT2. Since the high-temperature circuit sampling resistor R8 is in parallel with the second negative temperature coefficient resistor RT2, and the characteristic of the second negative temperature coefficient resistor RT2 is that its resistance value will change with temperature, the voltage of the high-temperature circuit sampling resistor R8 will change with the resistance value of the second negative temperature coefficient resistor RT2. As a result, the voltage of the high-temperature circuit sampling resistor R8 is obtained by the microcontroller through the high-temperature voltage signal acquisition terminal Temp_H, and further enables the microcontroller to calculate the actual high-temperature value through a preset algorithm based on the acquired voltage value.Furthermore, the temperature acquisition circuit 10 of the sodium-ion battery can also design multiple different temperature detection circuits according to the actual needs of users to meet the requirements of large battery modules for multiple temperature detection points, thereby achieving a more comprehensive monitoring of the battery temperature. Specifically, since the negative temperature coefficient resistor is composed of metal oxide materials, the carrier concentration of its materials is relatively low in a low-temperature environment, making its resistance value relatively high. A small increase in the ambient temperature can cause a significant change in the carrier concentration, which in turn leads to a large fluctuation in the resistance value of the negative temperature coefficient resistor. On the contrary, the carrier concentration of its materials is relatively high in a high-temperature environment, making its resistance value relatively low. A small decrease in the ambient temperature is difficult to cause a significant change in the carrier concentration, which in turn leads to a small fluctuation in the resistance value of the negative temperature coefficient resistor. Therefore, the low-temperature circuit sampling resistor R4 connected in series with the first negative temperature coefficient resistor RT1 in the low-temperature detection circuit needs to be a resistor with a relatively larger resistance value than the high-temperature circuit sampling resistor R8, so as to obtain a larger voltage change at low temperatures. The high-temperature circuit sampling resistor R8 connected in series with the second negative temperature coefficient resistor RT2 in the high-temperature detection circuit needs to be a resistor with a relatively smaller resistance value than the low-temperature circuit sampling resistor R4, so as to maintain an appropriate voltage change range at high temperatures, thereby accurately detecting the actual temperature.

[0048] Compared with the prior art, the present disclosure has at least the following advantages:

[0049] 1. For the above-mentioned temperature acquisition circuit 10 of the sodium-ion battery, the microcontroller can respectively control the high-temperature detection enable signal terminal EN_Temp_H and the low-temperature detection enable signal terminal EN_Temp_L to output level signals to the first electronic switch tube M1 and the second electronic switch tube M2 according to the actual ambient temperature of the battery, so that one of the first electronic switch tube M1 and the second electronic switch tube M2 is in the conducting state, and the other electronic switch tube is in the cut-off state, enabling the temperature acquisition circuit 10 of the sodium-ion battery to only enable the low-temperature or high-temperature detection circuit to work alone at the same time, thereby avoiding the problem of data acquisition deviation of the microcontroller caused by enabling the low-temperature and high-temperature detection circuits simultaneously, and further ensuring the normal operation of the temperature acquisition circuit 10 of the sodium-ion battery and preventing the acquisition data from being confused.

[0050] 2. Further, since the resistance value of the negative temperature coefficient resistor changes significantly with temperature in a low-temperature environment and changes relatively little with temperature in a high-temperature environment, the resistance value of the low-temperature circuit sampling resistor R4 is relatively higher than that of the high-temperature circuit sampling resistor R8, so that the microcontroller can collect a more significant voltage change range, and thus can accurately detect and reflect the actual temperature change.

[0051] 3. Further, the sodium-ion battery temperature acquisition circuit 10 can be designed with multiple temperature detection circuits to meet the requirements of multiple temperature detection points in a large battery module, thereby improving the accuracy and applicability of the sodium-ion battery temperature acquisition circuit 10.

[0052] The above-described embodiments merely represent several implementation manners of the present disclosure. The description thereof is relatively specific and detailed, but it should not be construed as a limitation to the scope of the disclosed patent. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present disclosure, several variations and improvements can still be made, and these all fall within the protection scope of the present disclosure. Therefore, the protection scope of the present disclosure patent shall be subject to the appended claims.

Claims

1. A sodium-ion battery temperature acquisition circuit, characterized in that It includes a microcontroller, a high-temperature detection circuit and a low-temperature detection circuit. The low-temperature detection circuit includes a first current-limiting resistor, a first negative temperature coefficient resistor, a low-temperature circuit sampling resistor and a first electronic switch tube. The first end of the first electronic switch tube is used to connect to the power supply terminal. The second end of the first electronic switch tube is connected to the first end of the first negative temperature coefficient resistor. The control end of the first electronic switch tube is connected to the first end of the first current-limiting resistor. The second end of the first negative temperature coefficient resistor is grounded. The second end of the first current-limiting resistor is connected to the low-temperature detection enable signal terminal of the microcontroller. The first end of the low-temperature circuit sampling resistor is connected to the first end of the first negative temperature coefficient resistor. The second end of the low-temperature circuit sampling resistor is connected to the low-temperature voltage signal acquisition terminal of the microcontroller. The high-temperature detection circuit includes a second current-limiting resistor, a second negative temperature coefficient resistor, a high-temperature circuit sampling resistor and a second electronic switch tube. The first end of the second electronic switch tube is used to connect to the power supply terminal. The second end of the second electronic switch tube is connected to the first end of the second negative temperature coefficient resistor. The control end of the second electronic switch tube is connected to the first end of the second current-limiting resistor. The second end of the second negative temperature coefficient resistor is grounded. The second end of the second current-limiting resistor is connected to the high-temperature detection enable signal terminal of the microcontroller. The first end of the high-temperature circuit sampling resistor is connected to the first end of the second negative temperature coefficient resistor. The second end of the high-temperature circuit sampling resistor is connected to the high-temperature voltage signal acquisition terminal of the microcontroller. The microcontroller is used to control the output of level signals at the low-temperature detection enable signal terminal and the high-temperature detection enable signal terminal, and obtain the voltage values of the low-temperature circuit sampling resistor and the high-temperature circuit sampling resistor through the low-temperature voltage signal acquisition terminal and the high-temperature voltage signal acquisition terminal.

2. The temperature acquisition circuit of the sodium-ion battery according to claim 1, wherein The low-temperature detection circuit further includes a first voltage-dividing resistor. The first end of the first voltage-dividing resistor is used to connect to the power supply terminal. The second end of the first voltage-dividing resistor is connected to the first end of the first electronic switch tube.

3. The temperature acquisition circuit of the sodium-ion battery according to claim 2, characterized in that The low-temperature detection circuit further includes a first bias resistor. The first end of the first bias resistor is connected to the control end of the first electronic switch tube. The second end of the first bias resistor is grounded.

4. The sodium-ion battery temperature acquisition circuit according to claim 1, characterized in that, The high-temperature detection circuit further includes a second voltage-dividing resistor. The first end of the second voltage-dividing resistor is used to connect to the power supply terminal. The second end of the second voltage-dividing resistor is connected to the first end of the second electronic switch tube.

5. The temperature acquisition circuit of the sodium-ion battery according to claim 4, wherein The low-temperature detection circuit further includes a second bias resistor. The first end of the second bias resistor is connected to the control end of the second electronic switch tube. The second end of the second bias resistor is grounded.

6. The temperature acquisition circuit of the sodium-ion battery according to claim 1, wherein The resistance value of the low-temperature circuit sampling resistor is 100K ohms, and the resistance value of the high-temperature circuit sampling resistor is 10K ohms.

7. The temperature acquisition circuit of the sodium-ion battery according to claim 1, wherein The first electronic switch tube is an N-channel MOS tube.

8. The sodium-ion battery temperature acquisition circuit according to claim 1, wherein The second electronic switch tube is an N-channel MOS tube.

9. The temperature acquisition circuit of the sodium-ion battery according to claim 1, characterized in that At least one of the first current-limiting resistor and the second current-limiting resistor is a variable resistor.

10. A battery management system, characterized in that, It includes a sodium-ion battery temperature acquisition circuit as described in any one of claims 1 to 9 above.

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