Power battery system with wide temperature applicability and control method thereof

Abstract

The invention relates to a power battery system with wide temperature applicability and a control method thereof. The power battery system comprises a main working battery pack and a wide-temperature-range battery; the main working battery pack is used for outputting power of the power battery system; the wide-temperature-range battery is used for providing power output for heat dissipation of the main working battery pack; the refrigerating device is arranged on the surface of the main working battery pack; when the refrigeration device works, heat dissipation is carried out on the main working battery pack; the temperature monitoring module comprises a temperature sensor, a temperature analysis unit, a micro-control unit MCU and a module control unit, the current temperature of the main working battery pack is monitored and compared with a set temperature range, and power supply of the wide-temperature-range battery to the refrigeration device is controlled to be switched on or switched off based on a set mechanism; therefore, the refrigeration device is controlled to be started or stopped to dissipate heat of the main working battery pack, and the temperature of the main working battery pack is controlled within a proper range.

Description

Technical Field

[0001] The present invention relates to the technical field of power batteries, and in particular, to a power battery system with wide temperature applicability and a control method thereof. Background Art

[0002] With the wide application of new energy vehicles and energy storage devices, the working stability and safety of power battery systems in various complex environments have received extensive attention. Based on the influence of temperature on battery performance, many studies and patents have adopted different methods in order to improve the wide temperature applicability of batteries. Regarding the low-temperature environment preheating method, external preheating methods mainly using electric heating films and phase change materials (PCMs), and internal preheating methods mainly using pulse and DC discharges have been widely applied in the industry. Regarding the high-temperature environment refrigeration method, air cooling and liquid cooling are the current mainstream forms, and the relevant applications of direct cooling and thermoelectric material refrigeration are also gradually increasing. These methods have their own advantages and disadvantages and have gradually formed a systematic application.

[0003] In a high-temperature environment, the electrochemical performance of lithium-ion batteries significantly decreases, specifically manifested as an increase in internal resistance, a decrease in voltage platform, a weakening of power output ability, and even possible inability to work properly due to electrolyte decomposition or collapse of the electrode material structure. Therefore, in order to ensure the operating safety of the power battery system in a high-temperature environment, improving its temperature control ability at high temperatures has become one of the key directions of technology research and development.

[0004] In addition, most research, patents, and applications focus on the single scenario of battery preheating in a low-temperature environment or refrigeration in a high-temperature environment. The systems designed from this single scenario may accelerate battery damage or even failure in the opposite temperature scenario. This means that the thermal management systems using such single preheating or cooling can largely not simultaneously meet the robustness of the system and the applicability of the battery under different temperature conditions. In addition, the internal or external preheating methods adopted by many existing preheating systems often use the working battery as the power source. While these working batteries are performing work output, they must also consume a part of the power for their own heating; at the refrigeration (heat dissipation) system level, using the working battery as the power source to cool itself is also the choice of most active cooling systems. Summary of the Invention

[0005] The purpose of the present invention is to address the defects existing in the prior art, and provide a power battery system with wide temperature applicability and a control method thereof. Through the power output of a wide temperature range battery to a refrigeration device combined with temperature monitoring and control, the temperature control adjustment of the power battery system in a high-temperature environment is realized, ensuring the stable and safe operation of the system.

[0006] To achieve the above object, in a first aspect, the present invention provides a power battery system with wide temperature applicability, comprising:

[0007] A battery pack module, comprising: a main working battery pack and a wide temperature range battery; the main working battery pack is used for power output of the power battery system; the wide temperature range battery is used to provide power output for heat dissipation of the main working battery pack;

[0008] A refrigeration device, disposed on the surface of the main working battery pack; when the refrigeration device works, it dissipates heat from the main working battery pack;

[0009] A temperature monitoring and control module, comprising: a temperature sensor, a temperature analysis unit, a micro control unit MCU and a module control unit;

[0010] The temperature sensor is used to collect the temperature signal of the main working battery pack in real time; the temperature analysis unit is used to determine whether the current temperature of the main working battery pack is higher than a first preset threshold or lower than a second preset threshold according to the temperature signal; the temperature analysis unit issues a first control signal when it confirms that the current temperature is higher than the first preset threshold; the micro control unit MCU is used to generate a refrigeration start control instruction according to the first control signal; the module control unit controls the conduction of the circuit connection between the wide temperature range battery and the refrigeration device according to the refrigeration start control instruction, so that the refrigeration device works through the power output of the wide temperature range battery to reduce the temperature of the main working battery pack; when it is first confirmed that the current temperature is lower than the second preset threshold after the temperature analysis unit issues the first control signal, a second control signal is issued, the micro control unit MCU is used to generate a refrigeration shutdown control instruction according to the second control signal, and the module control unit controls the disconnection of the circuit connection between the wide temperature range battery and the refrigeration device according to the refrigeration shutdown control instruction; wherein, the temperature corresponding to the first preset threshold is not lower than the temperature corresponding to the second preset threshold.

[0011] Preferably, the power battery system further comprises: a solar cell and a state of charge monitoring module;

[0012] The state of charge monitoring module comprises: a state of charge sampling circuit and a solar charging access control unit;

[0013] The state of charge sampling circuit is used to collect the voltage data of the wide temperature range battery in real time, and generate a normalized state of charge detection signal according to the voltage data and send it to the control unit;

[0014] The solar charging access control unit is used to judge whether the state of charge SOC of the current wide temperature range battery is lower than the lower limit of the preset state of charge threshold according to the normalized state of charge detection signal;

[0015] When the state of charge is lower than the lower limit of the preset state of charge threshold, the solar charging access control unit controls the conduction of the circuit connection between the solar cell and the wide-temperature-range battery, and charges the wide-temperature-range battery through the solar cell.

[0016] Further preferably, after the solar charging access control unit controls the conduction of the circuit connection between the solar cell and the wide-temperature-range battery, the state of charge sampling circuit continues to collect the voltage data of the wide-temperature-range battery in real time, and generates a normalized state of charge detection signal according to the voltage data and sends it to the control unit;

[0017] The solar charging access control unit also judges whether the current state of charge SOC of the wide-temperature-range battery is higher than the upper limit of the preset state of charge threshold according to the normalized state of charge detection signal;

[0018] When it is higher than the upper limit of the preset state of charge threshold, the solar charging access control unit controls the disconnection of the circuit connection between the solar cell and the wide-temperature-range battery.

[0019] Preferably, the power battery system further includes: a charging interface for the battery pack module to access the external power grid through the charging interface for charging;

[0020] The power battery system further includes: a mode recognition unit;

[0021] The mode recognition unit is used to detect the input voltage of the charging interface;

[0022] When the input voltage reaches or is higher than the preset voltage threshold, the battery pack module accesses the external power grid through the charging interface for charging.

[0023] Preferably, the power battery system further includes: a heating device disposed on the surface of the main working battery pack;

[0024] The temperature analysis unit is further used to determine whether the current temperature of the main working battery pack is lower than the third preset threshold according to the temperature signal; the temperature analysis unit issues a third control signal when it confirms that the current temperature is lower than the third preset threshold; the micro control unit MCU is further used to generate a heating start control instruction according to the third control signal; the module control unit controls the conduction of the circuit connection between the wide-temperature-range battery and the heating device according to the heating start control instruction, so that the heating device works through the power output of the wide-temperature-range battery to increase the temperature of the main working battery pack;

[0025] After the temperature analysis unit issues the third control signal, when it is first confirmed that the current temperature is higher than the fourth threshold, a fourth control signal is issued. The microcontroller unit MCU is used to generate a heating-off control instruction according to the fourth control signal, and the module control unit controls to disconnect the circuit connection between the wide-temperature battery and the heating device according to the heating-off control instruction. Among them, the temperature corresponding to the fourth preset threshold is not lower than the temperature corresponding to the third preset threshold and is lower than the first preset threshold.

[0026] Preferably, the power battery system further includes: a battery power monitoring module for monitoring the power of the main working battery pack.

[0027] The main working battery pack includes a lithium-ion battery pack; the wide-temperature battery is one of a sodium-ion battery, a sodium-ion battery pack, or a solid-state battery.

[0028] In a second aspect, an embodiment of the present invention provides a control method for the power battery system described in the first aspect above, including:

[0029] Real-time collect the temperature signal of the main working battery pack through a temperature sensor.

[0030] Determine whether the current temperature of the main working battery pack is higher than a first preset threshold or lower than a second preset threshold according to the temperature signal.

[0031] When it is confirmed that the current temperature is higher than the first preset threshold, a first control signal is issued, and a refrigeration start control instruction is generated according to the first control signal. Control to conduct the circuit connection between the wide-temperature battery and the refrigeration device, and make the refrigeration device work through the power output of the wide-temperature battery to reduce the temperature of the main working battery pack.

[0032] After the first control signal is issued, when it is first confirmed that the current temperature is lower than the second preset threshold, a second control signal is issued, and a refrigeration-off control instruction is generated according to the second control signal. Control to disconnect the circuit connection between the wide-temperature battery and the refrigeration device. Among them, the temperature corresponding to the first preset threshold is not lower than the temperature corresponding to the second preset threshold.

[0033] Preferably, the control method further includes:

[0034] Real-time collect the voltage data of the wide-temperature battery, and judge whether the state of charge SOC of the current wide-temperature battery is lower than the lower limit of the preset state of charge threshold according to the normalized state of charge detection signal generated by the voltage data.

[0035] When it is lower than the lower limit of the preset state of charge threshold, conduct the circuit connection between the solar battery and the wide-temperature battery, and charge the wide-temperature battery through the solar battery.

[0036] After connecting the circuit between the solar cell and the wide-temperature-range battery, continue to collect the voltage data of the wide-temperature-range battery in real time, and determine whether the current state of charge (SOC) of the wide-temperature-range battery is higher than the upper limit of the preset state of charge threshold according to the normalized state of charge detection signal generated from the voltage data.

[0037] When it is higher than the upper limit of the preset state of charge threshold, control to disconnect the circuit connection between the solar cell and the wide-temperature-range battery.

[0038] Preferably, the control method further includes: detecting the input voltage of the charging interface.

[0039] When the input voltage reaches or is higher than the preset voltage threshold, the battery pack module accesses the external power grid through the charging interface for charging; the battery pack module includes: the main working battery pack and the wide-temperature-range battery.

[0040] Preferably, the control method further includes:

[0041] Determine whether the current temperature of the main working battery pack is lower than the third preset threshold according to the temperature signal;

[0042] When it is confirmed that the current temperature is lower than the third preset threshold, issue a third control signal;

[0043] Generate a heating start control instruction according to the third control signal, control to connect the circuit between the wide-temperature-range battery and the heating device, so that the heating device works through the power output of the wide-temperature-range battery to increase the temperature of the main working battery pack;

[0044] After the temperature analysis unit issues the third control signal, when it is first confirmed that the current temperature is higher than the fourth threshold, issue a fourth control signal, generate a heating-off control instruction to disconnect the circuit connection between the wide-temperature-range battery and the heating device;

[0045] Wherein, the temperature corresponding to the fourth preset threshold is not lower than the temperature corresponding to the third preset threshold and is lower than the first preset threshold.

[0046] The power battery system with wide temperature applicability provided by the embodiments of the present invention enables the system to have the active heat dissipation ability in high-temperature environments through intelligent temperature monitoring and control and an independent power supply system for regulating the temperature of the main working battery. It can automatically start the heat dissipation mechanism when the temperature of the main working battery pack exceeds the set threshold, preventing battery performance degradation or safety hazards caused by overheating. The system integrates solar cells and a state of charge monitoring module, effectively and automatically monitoring the state of charge of the wide-temperature-range battery to ensure that the wide-temperature-range battery maintains sufficient power in various environments, thereby continuously providing stable power support for the refrigeration device. This design not only improves the energy self-sufficiency ability of the system but also enhances the reliability of thermal management under the condition of no external power supply, especially suitable for application scenarios with long-term operation or remote work.

[0047] The power battery system with wide temperature applicability proposed by the present invention improves the stability and safety of power batteries in high- and low-temperature environments, meets the requirements of complex working conditions, extends the battery life, and improves the overall reliability and energy utilization efficiency of the system. Brief Description of the Drawings

[0048] Figure 1 It is a schematic structural diagram of a power battery system with wide temperature applicability provided by the embodiments of the present invention;

[0049] Figure 2 It is one of the structural diagrams of the thermoelectric cooler provided by the embodiments of the present invention;

[0050] Figure 3 It is another structural diagram of the thermoelectric cooler provided by the embodiments of the present invention;

[0051] Figure 4 It is a schematic structural diagram of the thermoelectric cooler powered on provided by the embodiments of the present invention;

[0052] Figure 5 It is a schematic structural diagram of another power battery system with wide temperature applicability provided by the embodiments of the present invention;

[0053] Figure 6a It is a schematic diagram of an experimental device under the condition that a TEC cooler powered by a sodium-ion battery is added to the lithium-ion battery pack provided by the embodiments of the present invention;

[0054] Figure 6b It is a schematic diagram of an experimental device under the condition that no TEC cooler is added to the lithium-ion battery pack provided by the embodiments of the present invention;

[0055] Figure 7 It is a curve showing the relationship between relative capacity and number of cycles during the high-temperature cycle provided by the embodiments of the present invention;

[0056] Figure 8This is a simulation result curve showing the temperature rise of each battery cell during the 1C discharge of the lithium battery pack for 30 minutes under heat dissipation and non - heat dissipation conditions in the embodiments of the present invention. Detailed implementation manners

[0057] The technical solutions of the present invention will be further described in detail below with reference to the drawings and embodiments.

[0058] The embodiments of the present invention provide a power battery system with wide temperature applicability, and its main component structure is as Figure 1 shown in the structural schematic diagram of the power battery system with wide temperature applicability. First, the technical solutions of the present invention will be described in combination with Figure 1 to illustrate the technical solutions of the present invention.

[0059] The power battery system of the present invention includes:

[0060] The battery pack module 1, including: the main working battery pack 11 and the wide - temperature - range battery 12; the main working battery pack 11 is used for the power output of the power battery system; the wide - temperature - range battery 12 is used to provide power output for the heat dissipation of the main working battery pack 11.

[0061] The refrigeration device 2 is arranged on the surface of the main working battery pack 11; when the refrigeration device 2 works, it dissipates heat from the main working battery pack.

[0062] Preferably, the refrigeration device 2 in the present invention can be implemented by a thermoelectric cooler (TEC). A thermoelectric cooler is a solid - state refrigeration device based on the Peltier effect. Utilizing the Peltier effect of semiconductor materials, after passing direct current, when the direct current passes through a thermocouple pair composed of different semiconductor materials, heat is absorbed from one end (the cold end, in this example, the cold end is attached to the battery surface) and released at the other end (the hot end, and a heat sink can be externally connected to accelerate heat dissipation). The structure of this device usually consists of a thermopile composed of multiple thermocouple pairs to improve the refrigeration efficiency and temperature difference ability, and has the advantages of no mechanical moving parts, small volume, no noise, fast response, etc., and is suitable for efficient and precise temperature control management of the power battery system. Of course, using a thermoelectric cooler is only an optional implementation method for the refrigeration device 2. In specific implementations, the heat dissipation methods that can be used are not limited to using TEC, and other existing liquid - cooling, heat pipe and other methods, as well as the coupling between these methods, can also be used.

[0063] A typical structure of the thermoelectric cooler is as Figure 2 shown, with upper and lower ceramic substrates clamping semiconductor elements and metal conductor connecting pieces. The internal structure of the semiconductor elements and metal conductor connecting pieces is as Figure 3As shown. The semiconductor element includes P-type and N-type semiconductor elements, usually made of bismuth telluride (Bi2Te3) material. By arranging these P-type and N-type elements alternately, multiple thermocouple pairs are formed. Metal conductor connectors, most commonly copper connectors, are used to electrically connect the P-type and N-type semiconductor elements into a series circuit and at the same time provide a good heat conduction path. The ceramic substrate is composed of two upper and lower ceramic plates, and the material can be alumina, etc., which is used to clamp the semiconductor elements and copper connectors to provide structural support and electrical insulation. The structure of this thermoelectric cooler when powered on is as Figure 4 shown.

[0064] The temperature monitoring and control module 3 includes: a temperature sensor 31, a temperature analysis unit 32, a micro control unit (MCU) 33, and a module control unit 34;

[0065] The temperature sensor 31 is used to collect the temperature signal of the main working battery pack 11 in real time; the temperature sensor 31 can be a thermocouple, a thermistor or a digital temperature sensor, which is arranged on the surface or inside the housing of the main working battery pack 11, preferably on the surface, and outputs the temperature signal in real time through communication methods such as SPI or I 2 C. The sampling frequency can be from 1 Hz to 10 Hz to ensure timely feedback of temperature changes. Preferably, the temperature sensor 31 can also set a second temperature sampling point to collect the ambient temperature. By collecting the ambient temperature signal, it can be fused and analyzed with the temperature signal of the main working battery pack 11 to improve the accuracy and safety of the preheating strategy.

[0066] The temperature analysis unit 32 is used to determine whether the current temperature of the main working battery pack 11 is higher than a first preset threshold or lower than a second preset threshold according to the temperature signal. When the temperature analysis unit 32 confirms that the current temperature is higher than the first preset threshold, it issues a first control signal, and if it is not higher than the first preset threshold, it does not issue a signal; the micro control unit (MCU) 33 is used to generate a refrigeration start control instruction according to the first control signal; the module control unit 34 controls the circuit connection between the wide-temperature battery 12 and the refrigeration device 2 according to the refrigeration start control instruction, specifically through controlling the switch 35, so that the refrigeration device 2 works through the power output of the wide-temperature battery 12 to reduce the temperature of the main working battery pack 11; after the temperature analysis unit 32 issues the first control signal, when it is first confirmed that the current temperature is lower than the second preset threshold, it issues a second control signal, and the micro control unit (MCU) 33 is used to generate a refrigeration shutdown control instruction according to the second control signal, and the module control unit 34 controls the disconnection of the circuit connection between the wide-temperature battery 12 and the refrigeration device 2 according to the refrigeration shutdown control instruction. Among them, the temperature corresponding to the first preset threshold is higher than the temperature corresponding to the second preset threshold. The first preset threshold is the temperature threshold for starting the heat dissipation control, such as 45 °C, and the second preset threshold is the temperature threshold for exiting the heat dissipation control, such as 25 °C.

[0067] Furthermore, the power battery system further includes: a solar cell 4 and a state of charge monitoring module 5; the state of charge monitoring module 5 includes: a state of charge sampling circuit 51 and a solar charging access control unit 52.

[0068] The state of charge sampling circuit 51 is configured to collect voltage data of the wide-temperature-range battery 12 in real time, and generate a normalized state of charge detection signal according to the voltage data and send it to the control unit. The normalization process in the present invention can use any existing normalization method in the prior art to process the data. For example, preferably, the method of open circuit voltage-state of charge (OCV-SOC) correspondence can be used to obtain the normalized state of charge detection signal. By previously measuring the open circuit voltage-state of charge (OCV-SOC) correspondence of the used wide-temperature-range battery and performing cubic spline fitting processing to convert the interpolation data into a curve form, that is, the OCV-SOC curve. By comparing the detected battery voltage with the OCV-SOC curve, the current state of charge can be intuitively and simply evaluated. Among them, the OCV-SOC correspondence can be measured in the following manner: Step 1, at room temperature, fully charge the battery under standard working conditions (reference can be made to the specification or manual provided by the battery manufacturer); Step 2, leave it for 1 h to depolarize; Step 3, discharge at 0.05C for 1 h to release 5% of the power; Step 4, leave it for 1 h to depolarize, and record the voltage state after leaving; Step 5, repeat Steps 3 and 4 until the battery releases 95% of the power or reaches the cut-off voltage; Step 6, according to the recorded data, obtain the OCV-SOC correspondence. Another example is that a common linear transformation method can be used, that is, according to the minimum voltage and the maximum voltage of the wide-temperature-range battery 12, the voltage value corresponding to the current voltage data is scaled proportionally between 0 and 1. For example, if the working voltage range of the wide-temperature-range battery 12 is 2.5V to 4.2V, the current voltage value V corresponding to the voltage data collected in real time can be normalized by the following formula: Normalized state of charge detection signal = (V - 2.5) / (4.2 - 2.5). The methods provided above are only realizable ways, and in actual implementation, any existing normalization processing method in the prior art can be used to process the data.

[0069] The solar charging access control unit 52 is configured to determine whether the state of charge SOC of the current wide-temperature-range battery 12 is lower than the lower limit of the preset state of charge threshold, such as 50%, according to the normalized state of charge detection signal; when it is lower than the lower limit of the preset state of charge threshold, the solar charging access control unit 52 controls to conduct (for example, by controlling the closing of the switch 41) the circuit connection between the solar cell 4 and the wide-temperature-range battery 12, and charges the wide-temperature-range battery 12 through the solar cell 4.

[0070] After the solar charging access control unit 52 controls the conduction of the circuit connection between the solar cell 4 and the wide-temperature-range battery 12, the state-of-charge sampling circuit 51 continues to collect the voltage data of the wide-temperature-range battery 12 in real time, and generates a normalized state-of-charge detection signal according to the voltage data and sends it to the control unit; the solar charging access control unit 52 further determines whether the state of charge SOC of the current wide-temperature-range battery 12 is higher than the upper limit of the preset state-of-charge threshold, such as 80%; when it is higher than the upper limit of the preset state-of-charge threshold, the solar charging access control unit 52 controls to disconnect (for example, by controlling the disconnection of the switch 41) the circuit connection between the solar cell 4 and the wide-temperature-range battery 12.

[0071] In order to improve the self-sufficiency ability of the system and maintain the continuous output capacity of the wide-temperature-range battery during long-term operation, the solar cell 4 is also integrated. The state-of-charge monitoring module 5 monitors the voltage data of the wide-temperature-range battery 12 in real time, generates a normalized state-of-charge detection signal according to the voltage data, and judges the state of charge (SOC) of the battery. When the SOC is lower than the lower limit of the preset threshold, the system automatically conducts the circuit connection between the solar cell 4 and the wide-temperature-range battery 12 for charging, so that the wide-temperature-range battery 12 can maintain sufficient power even without an external power supply, providing continuous power support for the TEC cooler; when the SOC is higher than the upper limit of the preset threshold, the connection is automatically disconnected to prevent overcharging, thereby ensuring the stability and safety of the system.

[0072] The power battery system of the present invention further includes: a charging interface 6, through which the battery pack module 1 accesses the external power grid for charging.

[0073] The power battery system of the present invention further includes: a mode recognition unit 7.

[0074] The mode recognition unit 7 is used to detect the input voltage of the charging interface 6. Specifically, the mode recognition unit 7 may include a voltage detection circuit and a voltage comparator, and continuously monitors the voltage input situation on the charging interface 6. By comparing with a preset voltage threshold (such as 200V DC), the real-time recognition of the external power grid connection state is realized. When it is detected that the input voltage reaches or is higher than the preset voltage threshold, it is determined that the external power grid has been connected and enters the charging mode, and the battery pack module 1 accesses the external power grid for charging through the charging interface 6. In this state, the circuit connection between the solar cell 4 and the wide-temperature-range battery 12 is in a disconnected state. When the input voltage is lower than the preset voltage threshold, it indicates that the external power grid is not connected.

[0075] The power battery system of the present invention further includes: a battery power monitoring module 8, which is used to monitor the power of the main working battery pack 11; of course, it can also be used to monitor the power of the wide-temperature-range battery 12.

[0076] In a specific embodiment, the main working battery group 11 is a lithium-ion battery group; the wide-temperature battery 12 is one of a sodium-ion battery, a sodium-ion battery group, or a solid-state battery.

[0077] In an alternative solution, the power battery system of the present invention may further include a heating device 8, such as Figure 5 shown.

[0078] The heating device 8 is disposed on the surface of the main working battery group 11.

[0079] The temperature analysis unit 32 is further configured to determine whether the current temperature of the main working battery group 11 is lower than a third preset threshold, such as 10°C, according to the temperature signal; the temperature analysis unit 32 issues a third control signal when it is confirmed that the current temperature is lower than the third preset threshold; the micro control unit (MCU) 33 is further configured to generate a heating start control instruction according to the third control signal; the module control unit 34 controls the circuit connection between the wide-temperature battery 12 and the heating device 8 to be turned on according to the heating start control instruction, so that the heating device 8 operates through the power output of the wide-temperature battery 12 to increase the temperature of the main working battery group 11. The heating device 8 may specifically be a heating sheet or a heating tape, etc.

[0080] After the temperature analysis unit 32 issues the third control signal, when it is first confirmed that the current temperature is higher than a fourth threshold (such as 25°C), a fourth control signal is issued. The micro control unit (MCU) 33 is configured to generate a heating-off control instruction according to the fourth control signal, and the module control unit 34 controls the circuit connection between the wide-temperature battery 12 and the heating device 8 to be disconnected according to the heating-off control instruction; wherein, the temperature corresponding to the fourth preset threshold is not lower than the temperature corresponding to the third preset threshold and is lower than the temperature corresponding to the first preset threshold.

[0081] In this application, the switch 41 may specifically adopt a three-position switch to select or not select the connection between the wide-temperature battery 12 and the refrigeration device 2 or the heating device 8.

[0082] This solution can effectively avoid the degradation of battery performance or insufficient power output caused by low temperature, and provides a convenient and reliable technical support for the application of vehicles or equipment equipped with lithium-ion batteries in low-temperature environments.

[0083] Furthermore, for the system design solution and control method of installing a heating device in the power battery system to enable the power battery system to have a self-preheating function in a low-temperature environment, reference can be made to the patent application "Power Battery System with Self-Preheating Function in Low-Temperature Environment and Its Control Method" submitted by the applicant on the same day. This solution can be used as a specific implementation solution for the low-temperature environment heating function in the power battery system with wide-temperature applicability of the present invention and applied to the power battery system with wide-temperature applicability of the present invention.

[0084] For the over-temperature detection and control of the main working battery pack in the above system of the present invention, the control is carried out according to the following method.

[0085] Step 11: Collect the temperature signal of the main working battery pack in real time through a temperature sensor;

[0086] Step 12: Determine whether the current temperature of the main working battery pack is higher than a first preset threshold or lower than a second preset threshold according to the temperature signal;

[0087] Step 13: When it is confirmed that the current temperature is higher than the first preset threshold, issue a first control signal, and generate a refrigeration start control instruction according to the first control signal, control the conduction of the circuit connection between the wide-temperature battery and the refrigeration device, and make the refrigeration device work through the power output of the wide-temperature battery to reduce the temperature of the main working battery pack;

[0088] If the current temperature is not higher than the first preset threshold, continue to collect the temperature signal of the main working battery pack.

[0089] Step 14: After issuing the first control signal, continue to collect the temperature signal of the main working battery pack; when it is first confirmed that the current temperature is lower than the second preset threshold, issue a second control signal, and generate a refrigeration shutdown control instruction according to the second control signal, control the disconnection of the circuit connection between the wide-temperature battery and the refrigeration device;

[0090] Wherein, the temperature corresponding to the first preset threshold is not lower than the temperature corresponding to the second preset threshold.

[0091] During the whole working process of the system, the temperature signal of the main working battery pack is continuously collected to achieve the detection and regulation of the temperature of the main working battery pack during the whole working process of the system, and to avoid the situation of too high temperature of the main working battery pack. The execution subject and process in each step have been described when introducing the above system, and will not be elaborated here.

[0092] It should be noted that the real-time collection mentioned in the present invention can be real-time temperature collection in continuous time, or temperature collection at set equal or unequal time intervals. That is, the "real-time collection" in the text means that the system can collect the current temperature or the corresponding voltage data in a timely enough manner according to a predetermined control strategy, and is used for subsequent judgment and control decision-making, rather than being understood in a narrow sense as completely continuous and uninterrupted in time.

[0093] Preferably, the control method further includes the low-temperature state detection and temperature control of the main working battery pack, including:

[0094] Step 21: Real-time collect the temperature signal of the main working battery pack through a temperature sensor, and determine whether the current temperature of the main working battery pack is lower than a third preset threshold according to the temperature signal;

[0095] Step 22: Send a third control signal when it is confirmed that the current temperature is lower than the third preset threshold; otherwise, continue to perform real-time collection of the temperature signal of the main working battery pack;

[0096] Step 23: Generate a heating start control instruction according to the third control signal, control the conduction of the circuit connection between the wide-temperature battery and the heating device, so that the heating device works through the power output of the wide-temperature battery to increase the temperature of the main working battery pack;

[0097] Step 24: After the temperature analysis unit sends the third control signal, when it is first confirmed that the current temperature is higher than the fourth threshold, send a fourth control signal, generate a heating-off control instruction, and disconnect the circuit connection between the wide-temperature battery and the heating device;

[0098] Among them, the temperature corresponding to the fourth preset threshold is not lower than the temperature corresponding to the third preset threshold and is lower than the first preset threshold. The third preset threshold is the temperature threshold for judging whether to start heating, that is, the judgment threshold for entering the heating mode; the fourth preset threshold is the temperature threshold for judging whether to end heating, that is, the judgment threshold for exiting the heating mode. Preferably, designing the third preset threshold to be lower than the fourth preset threshold can avoid frequent start and stop of the heating device and improve the stability and response rationality of the system.

[0099] The control method of the present invention further includes detecting the state of charge of the wide-temperature battery. The specific method includes:

[0100] Step 31: Real-time collect the voltage data of the wide-temperature battery, and judge whether the current state of charge (SOC) of the wide-temperature battery is lower than the lower limit of the preset state of charge threshold according to the normalized state of charge detection signal generated from the voltage data;

[0101] Step 32: When it is lower than the lower limit of the preset state of charge threshold, conduct the circuit connection between the solar cell and the wide-temperature battery, and charge the wide-temperature battery through the solar cell; otherwise, continue to collect voltage data and make judgments;

[0102] Step 33: After conducting the circuit connection between the solar cell and the wide-temperature battery, continue to real-time collect the voltage data of the wide-temperature battery, and judge whether the current state of charge (SOC) of the wide-temperature battery is higher than the upper limit of the preset state of charge threshold according to the normalized state of charge detection signal generated from the voltage data;

[0103] Step 34: When it is higher than the upper limit of the preset state of charge threshold, control to disconnect the circuit connection between the solar cell and the wide-temperature battery.

[0104] Through the above method, it is possible to ensure that the wide-temperature-range battery maintains sufficient power in various environments, thereby continuously providing stable power support for the refrigeration device.

[0105] The control method of the present invention further includes detecting whether an external charging power source is connected, and the specific method includes:

[0106] Step 41, detecting the input voltage of the charging interface;

[0107] Step 42, when the input voltage of the charging interface reaches or is higher than the preset voltage threshold, the battery pack module accesses the external power grid through the charging interface for charging.

[0108] The battery pack module mentioned here includes the main working battery pack and the wide-temperature-range battery.

[0109] In the state where the battery pack module accesses the external power grid through the charging interface for charging, the solar charging access control unit is turned off. Specifically, this control can be achieved by the mode recognition unit sending an enable signal to the solar charging access control unit.

[0110] Accessing the external power grid through the charging interface for charging is a commonly used technical means in the art, and will not be elaborated in detail here.

[0111] The power battery system with wide-temperature adaptability provided by the embodiments of the present invention, through intelligent temperature monitoring and control and an independent power supply system for regulating the temperature of the main working battery, enables the system to have the ability of active heat dissipation in high-temperature environments, and can automatically start the heat dissipation mechanism when the temperature of the main working battery pack exceeds the set threshold, preventing battery performance degradation or safety hazards caused by overheating. The system integrates a solar battery and a state-of-charge monitoring module, effectively and automatically monitors the state of charge of the wide-temperature-range battery, ensures that the wide-temperature-range battery maintains sufficient power in various environments, and thus continuously provides stable power support for the refrigeration device. This design not only improves the energy self-sufficiency ability of the system, but also enhances the reliability of thermal management under the condition of no external power supply. It is especially suitable for application scenarios with long-term operation or remote work, improves the operation reliability and safety of the power battery system in a wide-temperature environment, and has high practical value and application prospects.

[0112] In order to verify the performance of the power battery system proposed by the present invention, the present invention conducted a comparative experiment with a group of power battery systems having a main working battery pack and a wide-temperature-range battery as described above, and a group of power battery systems having only a main working battery pack.

[0113] The experimental system is schematically shown as Figure 6a 、 6b shown. Figure 6aThe TEC cooler in Figure 6b is powered by a sodium-ion battery. These two figures mainly illustrate the corresponding relationship between the positions and numbers of the battery cells in the lithium-ion battery pack (such as Figure 6a ), as well as the position of the TEC cooler (such as

[0114] ). Therefore, the power connection part with the sodium-ion battery is not drawn in Figure a.

[0115] Therefore, based on the pseudo-two-dimensional (P2D) model of the porous electrode theory, a mechanism describing the dynamics of the SEI film was introduced into the model to reflect the influence of high temperature on the capacity loss of the lithium-ion battery cells used in the present invention during the cycling process under different temperature conditions (25 °C, 35 °C, 45 °C, 55 °C, 65 °C). The relationship curve between the relative capacity (relative capacity = current available capacity / initial capacity × 100%) and the number of cycles was obtained, as shown in Figure 7 .

[0116] It can be seen from Figure 7 that at the same number of cycles, the attenuation degree of the relative capacity of the battery at each temperature can be observed. The higher the temperature, the faster the relative capacity decays, indicating that high temperature accelerates the degradation of battery performance. Under the extremely high temperature condition of 65 °C, the curve drops more rapidly, indicating that high temperature will cause serious side reactions, resulting in structural damage or lithium dendrite growth. Therefore, in practical applications, long-term operation at high temperature should be avoided or thermal management should be strengthened.

[0117] In this embodiment, the COMSOL Multiphysics multi-physics simulation software was used to simulate the temperature changes of the battery cells in the lithium-ion battery pack under two working conditions: with the TEC cooler for refrigeration (heat dissipation) and without heat dissipation.

[0118] The specific process is as follows:

[0119] 1) Model construction:

[0120] According to Figure 6a 、 6b shown, a battery pack model containing 3 lithium-ion batteries and with or without 2 TEC coolers is constructed. In the figure, the large cylinders are lithium-ion batteries, numbered as cell 1, cell 2, and cell 3 in sequence along the positive x-axis; the outermost cube is the air domain, and the small cylinders and cuboids above the batteries are metal connection pieces (here the small cylinders are made of aluminum; the cuboids are made of nickel); in the heat dissipation condition model ( Figure 6a ), the cubic structure closely attached to the surface of the air domain is the TEC cooler. Only the structure of one side is shown here, and TEC coolers are also attached at the corresponding positions on the other side. Its materials include ceramic chips, metal copper sheets, and bismuth telluride alloys. The specific structure is as Figure 2 、 Figure 3 shown.

[0121] 2) Select domain materials and set their properties.

[0122] The thermophysical parameters of air, aluminum, nickel, copper, ceramic, and bismuth telluride alloy are directly taken from the material library built into COMSOL. The battery body is equivalently processed to simplify the calculation. Its radial thermal conductivity is 1 W / (m·K), the circumferential and axial thermal conductivities are 30 W / (m·K), the density is 2000 kg / m 3 , and the specific heat capacity is 750 J / (kg·K).

[0123] 3) Physical field settings.

[0124] In the non-heat dissipation model, only the battery pack interface (electrochemical field) and the solid heat transfer interface (temperature field) are selected, and the coupling effect between them, that is, the electrochemical heat effect, is added to realize the interaction between the heat generated by the battery pack during discharge and the ambient temperature. The heat dissipation model adds a current interface on the basis of the battery pack interface and the solid heat transfer interface, and expands the interaction relationship between multiple physical fields from electrochemical heat to electrochemical heat, electromagnetic heat, and thermoelectric effect to comprehensively consider the mutual influence among the heat generated by the battery pack during discharge, the ambient temperature, the thermoelectric effect caused by the current flowing through the TEC, and the electromagnetic heat caused by the current flowing through the metal copper sheet.

[0125] 4) Mesh generation.

[0126] Mesh generation is carried out through the adaptive mesh generation function of COMSOL.

[0127] 5) Calculation.

[0128] The calculation was carried out in transient mode with a time step of 10 s. The discharge process of the lithium battery within 1800 s was calculated, and the average temperature change of the battery cells was traced and recorded by setting domain probes (3 domain probes corresponding to battery cells No. 1 to No. 3).

[0129] 6) Post-processing.

[0130] The recorded temperature data points were exported to Excel and processed and plotted using Origin software to show the temperature rise of each battery cell under heat dissipation and non-heat dissipation conditions in one graph.

[0131] The relevant formulas, parameters, and boundary conditions of the model are set as follows:

[0132] 1. Battery pack interface - Calculate the battery voltage corresponding to the state of charge and temperature from parameters such as the equilibrium potential, the temperature derivative of the equilibrium potential, and the overpotential.

[0133] The scope of action of the battery pack interface is only the 3 battery cells and the metal connection part in the geometric model. In this interface, the capacity of the lithium battery cell is set to 15 Ah, and the initial state of charge of the battery pack is set to 1 (to simulate the discharge process). The current conductor is selected as the metal connection piece, and the negative and positive connectors are both selected as the corresponding boundaries. In the battery settings, the voltage losses caused by the ohmic overpotential, activation overpotential, and concentration overpotential are considered, and the Arrhenius relation factor is added to introduce the influence of temperature change on the overpotential. The reference temperature is taken as 25 °C, and the corresponding expressions are shown in Equations 1 - 3. The equilibrium potential and the temperature derivative of the equilibrium potential are fitted using interpolation functions.

[0134] 1C ohmic overpotential η IR，1C = eta_1C * Arrh(Ea_eta1C, bp.T_cell) (Equation 1)

[0135] In the formula, eta_1C is the 1C ohmic overpotential at the reference temperature, with the unit V; Arrh() is the Arrhenius relation factor with the activation energy and temperature as independent variables; Ea_eta1C is the activation energy related to the ohmic overpotential, with the unit J / mol; bp.T_cell is the battery temperature, with the unit K;

[0136] Dimensionless charge transfer current J0 = J 0_0 * Arrh(Ea_J0, bp.T_cell) (Equation 2)

[0137] In the formula, J0 is the dimensionless exchange current; J 0_0 is the dimensionless exchange current at the reference temperature; Arrh() is the Arrhenius relation factor with the activation energy and temperature as independent variables; Ea_J0 is the activation energy related to the activation overpotential, with the unit J / mol; bp.T_cell is the battery temperature, with the unit K;

[0138] The diffusion time constant τ = τ0 * Arrh(Ea_Tau, bp.T_cell) (Equation 3)

[0139] τ is the diffusion time constant, in s; τ0 is the diffusion time constant at the reference temperature, in s; Arrh() is the Arrhenius relationship factor, with the activation energy and temperature as independent variables; Ea_Tau is the activation energy related to the concentration overpotential, in J / mol; bp.T_cell is the battery temperature, in K.

[0140] In this interface, the open-circuit voltage of the battery consists of the equilibrium potential and the overpotential, that is

[0141] E_cell = E OCV (SOC,T) + η IR + η act + η conc (Equation 4)

[0142] Among them, E OCV (SOC,T) represents the equilibrium potential, which is related to the state of charge (SOC, State of Charge) and temperature, and is given by an interpolation function in the model. η IR represents the ohmic overpotential, η act represents the activation overpotential, η conc represents the concentration overpotential, which is related to the diffusion time constant τ. Correspondingly, I cell represents the actually applied battery current; I 1C represents the 1C current; R and F are the ideal gas constant (8.314 J / (mol·K)) and the Faraday constant (96485 C / mol); asinh() is the inverse hyperbolic sine function.

[0143] 2. The solid heat transfer interface - describes the temperature transfer and distribution of the entire model.

[0144] The scope of the solid heat transfer interface is the entire geometric part, and specifically divides the battery layer, the fluid domain, and other solid domains to represent the battery pack, air, and the remaining solid components (metal connectors and TEC) respectively. In this interface, the reference temperature is defined as 25 °C (the role of the reference temperature is to serve as a reference point for material properties), and parameters such as the specific heat capacity, thermal conductivity, and density of each component have been set in the material part during the modeling process. The initial temperature value is set to 45 °C (the role of the initial temperature value is to serve as the temperature calculation point at the start of the simulation). The heat flux boundary selects all boundaries, and the heat transfer coefficient is set to 30 W / (m 2 ·K).

[0145] The core method of this interface is the heat balance equation (heat accumulation + heat conduction + heat convection = heat source and sink), that is

[0146]

[0147] where ρ represents the material density; C P represents the specific heat capacity of the material; T represents the temperature; t represents the time, reflecting the transient process; U represents the flow velocity (related to fluid flow, which is ignored in this model); q represents the heat flux; Q represents the heat source; Q ted represents the thermal expansion loss (related to stress, which is ignored in this model).

[0148] 3. Current interface - Calculate the potential distribution by solving the current conservation equation.

[0149] The scope of the current interface is the copper sheet and PN junction in the TEC cooler. Specifically, only the copper sheet boundaries of the ground and the terminal need to be selected. The default potential of the ground boundary is 0, and the current type is selected for the terminal boundary, and the value is set to 8A. The underlying mechanism is the current conservation equation, that is

[0150]

[0151] where J represents the current density vector; Q j,V represents the current source term. In particular, when Q j,V = 0, it represents current conservation.

[0152] 4. Coupling between physical field interfaces.

[0153] The biggest feature of the COMSOL simulation software is to achieve the mutual coupling between different physical field interfaces. Each interface represents a specific physical field. In this model, there is an electrochemical-thermal coupling effect between the battery pack interface and the solid heat transfer interface; there are thermoelectric effects and electromagnetic-thermal coupling effects between the current interface and the solid heat transfer interface. It is precisely through their mutual coupling that the temperature changes in the battery caused by electrochemical reactions are related to the ambient temperature, and the electrothermal generation caused by electromagnetic-thermal and thermoelectric effects when current flows through metal devices and PN junctions are related to each other, so as to simulate a more realistic physical scenario.

[0154] For Figure 6a 、 6b two models are simulated, and data are extracted and plotted for the simulation results of the temperature rise of each battery cell during the 1C discharge of the lithium battery pack for 30 minutes under the heat dissipation and non-heat dissipation conditions. The results are as Figure 8 shown.

[0155] Through Figure 8It can be seen that under the condition of no heat dissipation, the temperatures of all the battery cells in the model increase with time, and the final temperatures all exceed 52°C, and the temperature increases relatively rapidly during the whole process. This indicates that without heat dissipation control, the heat accumulation inside the battery cells is serious. Under the condition of heat dissipation, the temperature rise rates of all the battery cells in the model are significantly reduced, indicating that more effective heat dissipation control is achieved. Among them, the heat dissipation effect of the No. 2 battery cell is the most significant, which is directly related to the position of the TEC cooler in the model. Since the No. 2 battery cell is cooled by the TEC coolers on both the front and back sides, the heat dissipation effect is the most significant. Thus, it can be seen that for the power battery system proposed by the present invention, its heat dissipation function can significantly reduce the temperature rise of the battery cells and effectively delay the accumulation of the battery cell temperature.

[0156] Those skilled in the art should also be able to further realize that the units and algorithm steps of each example described in combination with the embodiments disclosed herein can be implemented by electronic hardware, computer software, or a combination of the two. To clearly illustrate the interchangeability of hardware and software, the composition and steps of each example have been generally described according to functions in the above description. Whether these functions are executed in a hardware or software manner depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered to exceed the scope of the present invention.

[0157] The steps of the method or algorithm described in combination with the embodiments disclosed herein can be implemented by hardware, software modules executed by a processor, or a combination of the two. The software modules can be placed in a random access memory (RAM), internal memory, read-only memory (ROM), electrically programmable ROM, electrically erasable programmable ROM, registers, hard disk, removable disk, CD-ROM, or any other form of storage medium well-known in the technical field.

[0158] The specific embodiments described above further elaborate on the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above description is only the specific embodiments of the present invention and is not used to limit the protection scope of the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A power battery system with wide temperature applicability, characterized in that, The power battery system includes: A battery pack module, including: a main working battery pack and a wide-temperature-range battery; the main working battery pack is used for the power output of the power battery system; the wide-temperature-range battery is used to provide power output for the heat dissipation of the main working battery pack; A refrigeration device, disposed on the surface of the main working battery pack; when the refrigeration device works, it dissipates heat from the main working battery pack; A temperature monitoring and control module, including: a temperature sensor, a temperature analysis unit, a micro control unit MCU, and a module control unit; The temperature sensor is used to collect the temperature signal of the main working battery pack in real time; the temperature analysis unit is used to determine whether the current temperature of the main working battery pack is higher than a first preset threshold or lower than a second preset threshold according to the temperature signal; the temperature analysis unit issues a first control signal when it confirms that the current temperature is higher than the first preset threshold; the micro control unit MCU is used to generate a refrigeration start control instruction according to the first control signal; the module control unit controls the conduction of the circuit connection between the wide-temperature-range battery and the refrigeration device according to the refrigeration start control instruction, so that the refrigeration device works through the power output of the wide-temperature-range battery to reduce the temperature of the main working battery pack; when it is first confirmed that the current temperature is lower than the second preset threshold after the temperature analysis unit issues the first control signal, a second control signal is issued, the micro control unit MCU is used to generate a refrigeration shutdown control instruction according to the second control signal, and the module control unit controls the disconnection of the circuit connection between the wide-temperature-range battery and the refrigeration device according to the refrigeration shutdown control instruction; wherein, the temperature corresponding to the first preset threshold is not lower than the temperature corresponding to the second preset threshold.

2. The power battery system according to claim 1, wherein The power battery system further includes: a solar cell and a state of charge monitoring module; The state of charge monitoring module includes: a state of charge sampling circuit and a solar charging access control unit; The state of charge sampling circuit is used to collect the voltage data of the wide-temperature-range battery in real time, and generate a normalized state of charge detection signal according to the voltage data and send it to the control unit; The solar charging access control unit is used to judge whether the state of charge SOC of the current wide-temperature-range battery is lower than a preset state of charge threshold lower limit according to the normalized state of charge detection signal; When it is lower than the preset state of charge threshold lower limit, the solar charging access control unit controls the conduction of the circuit connection between the solar cell and the wide-temperature-range battery, and charges the wide-temperature-range battery through the solar cell.

3. The power battery system according to claim 2, wherein After the solar charging access control unit controls the conduction of the circuit connection between the solar cell and the wide-temperature-range battery, the state of charge sampling circuit continues to collect the voltage data of the wide-temperature-range battery in real time, and generates a normalized state of charge detection signal according to the voltage data and sends it to the control unit; The solar charging access control unit also judges whether the state of charge SOC of the current wide-temperature-range battery is higher than a preset state of charge threshold upper limit according to the normalized state of charge detection signal; When the state of charge is higher than the upper limit of the preset state of charge threshold, the solar charging access control unit controls to disconnect the circuit connection between the solar cell and the wide-temperature battery.

4. The power battery system according to claim 1, characterized in that, The power battery system further includes: a charging interface for the battery pack module to access the external power grid through the charging interface for charging; The power battery system further includes: a mode recognition unit; The mode recognition unit is used to detect the input voltage of the charging interface; When the input voltage reaches or is higher than the preset voltage threshold, the battery pack module accesses the external power grid through the charging interface for charging.

5. The power battery system according to claim 1, characterized in that The power battery system further includes: a heating device disposed on the surface of the main working battery pack; The temperature analysis unit is further configured to determine whether the current temperature of the main working battery pack is lower than a third preset threshold according to the temperature signal; the temperature analysis unit issues a third control signal when it confirms that the current temperature is lower than the third preset threshold; the micro control unit MCU is further configured to generate a heating start control instruction according to the third control signal; the module control unit controls to conduct the circuit connection between the wide-temperature battery and the heating device according to the heating start control instruction, so that the heating device works through the power output of the wide-temperature battery to increase the temperature of the main working battery pack; After the temperature analysis unit issues the third control signal, when it is first confirmed that the current temperature is higher than a fourth threshold, a fourth control signal is issued. The micro control unit MCU is used to generate a heating-off control instruction according to the fourth control signal, and the module control unit controls to disconnect the circuit connection between the wide-temperature battery and the heating device according to the heating-off control instruction; wherein, the temperature corresponding to the fourth preset threshold is not lower than the temperature corresponding to the third preset threshold and is lower than the first preset threshold.

6. The power battery system according to claim 1, wherein The power battery system further includes: a battery power monitoring module for monitoring the power of the main working battery pack; The main working battery pack includes a lithium-ion battery pack; the wide-temperature battery is one of a sodium-ion battery, a sodium-ion battery pack or a solid-state battery.

7. A control method for the power battery system according to any one of the above claims 1-6, characterized in that, The control method includes: Real-time collecting the temperature signal of the main working battery pack through a temperature sensor; Determining whether the current temperature of the main working battery pack is higher than a first preset threshold or lower than a second preset threshold according to the temperature signal; When it is confirmed that the current temperature is higher than the first preset threshold, a first control signal is issued, and a refrigeration start control instruction is generated according to the first control signal, and the circuit connection between the wide-temperature battery and the refrigeration device is controlled to be conducted, so that the refrigeration device works through the power output of the wide-temperature battery to reduce the temperature of the main working battery pack; After the first control signal is issued, when it is first confirmed that the current temperature is lower than the second preset threshold, a second control signal is issued, and a refrigeration-off control instruction is generated according to the second control signal, and the circuit connection between the wide-temperature battery and the refrigeration device is controlled to be disconnected; wherein, the temperature corresponding to the first preset threshold is not lower than the temperature corresponding to the second preset threshold.

8. The control method according to claim 7, wherein The control method further includes: Collect the voltage data of the wide-temperature-range battery in real time, and judge whether the state of charge (SOC) of the current wide-temperature-range battery is lower than the lower limit of the preset state of charge threshold according to the normalized state of charge detection signal generated from the voltage data; When it is lower than the lower limit of the preset state of charge threshold, turn on the circuit connection between the solar cell and the wide-temperature-range battery, and charge the wide-temperature-range battery through the solar cell; After turning on the circuit connection between the solar cell and the wide-temperature-range battery, continue to collect the voltage data of the wide-temperature-range battery in real time, and judge whether the state of charge (SOC) of the current wide-temperature-range battery is higher than the upper limit of the preset state of charge threshold according to the normalized state of charge detection signal generated from the voltage data; When it is higher than the upper limit of the preset state of charge threshold, control to disconnect the circuit connection between the solar cell and the wide-temperature-range battery.

9. The control method according to claim 7, wherein The control method further includes: Detect the input voltage of the charging interface; When the input voltage reaches or is higher than the preset voltage threshold, the battery pack module accesses the external power grid through the charging interface for charging; the battery pack module includes: the main working battery pack and the wide-temperature-range battery.

10. The control method according to claim 7, wherein The control method further includes: Determine whether the current temperature of the main working battery pack is lower than the third preset threshold according to the temperature signal; Send a third control signal when it is confirmed that the current temperature is lower than the third preset threshold; Generate a heating start control instruction according to the third control signal, control to turn on the circuit connection between the wide-temperature-range battery and the heating device, so that the heating device works through the power output of the wide-temperature-range battery to increase the temperature of the main working battery pack; After the temperature analysis unit sends the third control signal, when it is first confirmed that the current temperature is higher than the fourth threshold, send a fourth control signal, generate a heating-off control instruction to disconnect the circuit connection between the wide-temperature-range battery and the heating device; Wherein, the temperature corresponding to the fourth preset threshold is not lower than the temperature corresponding to the third preset threshold and is lower than the first preset threshold.

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