Sodium-ion battery charging control method and device, electronic equipment and storage medium

Abstract

The application relates to a sodium-ion battery charging control method and device, electronic equipment and a storage medium. The method comprises the following steps: obtaining the working temperature of a target battery, and determining a target temperature interval to which the working temperature belongs; determining a target charging parameter corresponding to the target temperature interval according to a first mapping relationship and a second mapping relationship; wherein the first mapping relationship represents the relationship between the temperature interval and the charging cut-off voltage, the second mapping relationship represents the relationship between the temperature interval and the charging rate, and the target charging parameter comprises a target charging cut-off voltage and a target charging rate; determining a target charging mode corresponding to the target battery based on the target temperature interval, wherein the target charging mode is at least one of a constant-current charging mode, a constant-voltage charging mode and a pulse charging mode; and controlling the target battery to charge according to the target charging parameter in the target charging mode. The method can effectively reduce the growth of sodium dendrites, reduce the risk of sodium precipitation and improve the service life of the battery.

Description

Technical Field

[0001] This application relates to the field of battery technology, and in particular to a sodium-ion battery charging control method, apparatus, electronic device, and storage medium. Background Technology

[0002] Sodium-ion batteries have gained widespread attention in recent years for their abundant sodium resources, low cost, and similar electrochemical principles to lithium-ion batteries, particularly in energy storage, low-speed electric vehicles, and applications in low-temperature environments. Compared to lithium-ion batteries, sodium-ion batteries exhibit superior low-temperature discharge performance, but their low-temperature charging performance still faces significant challenges.

[0003] Existing sodium-ion battery charging methods still have some problems. For example, at low temperatures, the electrolyte viscosity increases, the sodium ion diffusion coefficient in the negative electrode solid phase decreases sharply, and concentration polarization increases significantly, causing the negative electrode potential to drop below 0V prematurely, triggering irreversible sodium dendrite growth, and in severe cases, puncturing the separator and causing an internal short circuit. Another example is that if the charging rate of sodium-ion batteries is limited to a minimum in the low-temperature range, although this charging method can suppress sodium deposition, the charging time is extremely long, and the difference in the safe voltage window at different temperatures is not considered. Mechanically setting the charging cutoff voltage to a fixed value when charging sodium-ion batteries at different temperatures can easily cause the negative electrode potential of the sodium-ion battery to continue charging even after it has entered the sodium deposition region. Summary of the Invention

[0004] Therefore, it is necessary to provide a sodium-ion battery charging control method, device, electronic device, and storage medium to address the above-mentioned technical problems, which can effectively reduce the risk of sodium precipitation and improve battery life during the sodium-ion charging process.

[0005] In a first aspect, this application provides a sodium-ion battery charging control method, the method comprising:

[0006] Obtain the operating temperature of the target battery and determine the target temperature range to which the operating temperature belongs;

[0007] Based on the first and second mapping relationships, the target charging parameters corresponding to the target temperature range are determined; wherein, the temperature range includes the extremely low temperature region, the sub-low temperature region, the transition temperature region and the normal temperature region with the temperature values ​​arranged in ascending order; and the target charging parameters include the target charging cutoff voltage and the target charging rate.

[0008] Based on the target temperature range, the target charging mode corresponding to the target battery is determined. The target charging mode is at least one of constant current charging mode, constant voltage charging mode and pulse charging mode.

[0009] In target charging mode, the target battery is controlled to charge according to the target charging parameters;

[0010] The first mapping relationship represents the relationship between temperature range and charging cutoff voltage, and the second mapping relationship represents the relationship between temperature range and charging rate. The second mapping relationship includes a first rate-temperature relationship corresponding to the extremely low temperature region, a second rate-temperature relationship corresponding to the sub-low temperature region, a third rate-temperature relationship corresponding to the transition temperature region, and a fourth rate-temperature relationship corresponding to the normal temperature region. The first rate-temperature relationship is: the charging rate is a first preset rate. The second rate-temperature relationship is: the charging rate and operating temperature exhibit a third linear relationship with a third slope value and a third intercept. Both the third slope value and the third intercept are determined based on the temperature range value of the sub-low temperature region, the first preset rate, and the second preset rate. The second preset rate is greater than the first preset rate. The third rate-temperature relationship is: the charging rate and operating temperature exhibit a fourth linear relationship with a fourth slope value and a fourth intercept. Both the fourth slope value and the fourth intercept are determined based on the temperature range value of the transition temperature region, the second preset rate, and the third preset rate. The third preset rate is greater than the second preset rate. The fourth rate-temperature relationship is: the charging rate is any rate between the third preset rate and the maximum rate.

[0011] In one embodiment, the first mapping relationship includes a first voltage-temperature relationship corresponding to the extremely low temperature region, a second voltage-temperature relationship corresponding to the sub-low temperature region, a third voltage-temperature relationship corresponding to the transition temperature region, and a fourth voltage-temperature relationship corresponding to the normal temperature region.

[0012] The first voltage-temperature relationship is: the charging cutoff voltage is the first preset voltage;

[0013] The second voltage-temperature relationship is as follows: the charging cut-off voltage and the operating temperature exhibit a first linear relationship with a first slope value and a first intercept. The first slope value and the first intercept are both determined based on the temperature range value of the sub-low temperature region, the first preset voltage, and the second preset voltage. The second preset voltage is greater than the first preset voltage.

[0014] The third voltage-temperature relationship is as follows: the charging cut-off voltage and the operating temperature exhibit a second linear relationship with the second slope value and the second intercept. The second slope value and the second intercept are both determined based on the temperature range value of the transition temperature zone, the second preset voltage, and the third preset voltage. The third preset voltage is greater than the second preset voltage.

[0015] The fourth voltage-temperature relationship is: the charging cut-off voltage is the third preset voltage.

[0016] In one embodiment, the voltage parameter is set to any one of a first preset voltage, a second preset voltage, and a third preset voltage. Determining the voltage parameter includes:

[0017] The temperature sampling range used to determine the first preset voltage is set to the extremely low temperature region;

[0018] The temperature sampling range used to determine the second preset voltage is set to the sub-low temperature region and the transition temperature region;

[0019] The temperature sampling range used to determine the third preset voltage is set to the normal temperature range;

[0020] Multiple sample batteries are charged at any temperature within the temperature sampling range and at different charging rates. The battery voltage of the sample battery is recorded when the negative electrode potential first drops to zero at each charging rate, and the voltage set is obtained.

[0021] The median of the voltage set is used to determine the median as the voltage parameter.

[0022] In one embodiment, the magnification parameter is set to any one of a first preset magnification, a second preset magnification, and a third preset magnification. Determining the magnification parameter includes:

[0023] The temperature sampling range used to determine the first preset magnification is set to the extremely low temperature region;

[0024] The temperature sampling range used to determine the second preset magnification is set as the sub-low temperature region and the transition temperature region;

[0025] The temperature sampling range used to determine the third preset magnification is set to the normal temperature range;

[0026] Multiple sample batteries were charged at any temperature within the temperature sampling range and at different charging rates. The critical rate of the sample battery when the negative electrode potential first dropped to zero was recorded at each charging rate to obtain the rate set.

[0027] The median of the statistical multiplier set is used to determine the multiplier parameter.

[0028] In one embodiment, determining the target charging mode corresponding to the target battery based on the target temperature range includes:

[0029] When the target temperature range is in the extremely low temperature range, the target charging mode is determined to be the first charging mode, which is the constant current charging mode.

[0030] When the target temperature range is in the sub-low temperature range, the target charging mode is determined to be the second charging mode, which is a combination of pulse charging mode and constant voltage charging mode. The pulse charging mode is to charge the battery with pulse signals.

[0031] If the target temperature range falls within the transitional or normal temperature range, the target charging mode is determined to be the third charging mode, which is a combination of constant current charging mode and constant voltage charging mode.

[0032] In one embodiment, the target charging mode is a first charging mode, and the target battery is controlled to charge according to the target charging parameters, including:

[0033] Control the target battery to charge at the target charging rate and in constant current charging mode, and control the target battery to stop charging when it reaches the target charging cutoff voltage.

[0034] In one embodiment, when the target charging mode is a second charging mode, controlling the target battery to charge according to the target charging parameters includes:

[0035] The average current of the pulse signal is determined based on the target charging rate and the rated capacity of the target battery.

[0036] The peak current is determined based on the average current and the target duty cycle of the pulse signal.

[0037] The target battery is charged and its voltage is monitored using a pulse signal with peak current and target duty cycle.

[0038] When the battery voltage reaches the target charging cutoff voltage, the target battery is controlled to enter the constant voltage charging mode at the target charging cutoff voltage.

[0039] In one embodiment, monitoring the battery voltage of the target battery includes:

[0040] Real-time monitoring of voltage valleys within the pulse cycle;

[0041] When the voltage trough reaches the warning voltage, it is determined that the next positive pulse will touch the charging cutoff voltage.

[0042] In one embodiment, the process of determining the target duty cycle includes:

[0043] Select an operating temperature belonging to the sub-low temperature range, and determine the target charging rate and target charging cut-off voltage at the operating temperature;

[0044] The sample battery is charged using multiple preset duty cycle values ​​and target charging rates until the battery voltage reaches the target charging cutoff voltage, and the charging capacity after each charge is recorded.

[0045] Determine the maximum value among all charging capacities, and use the preset duty cycle value corresponding to the maximum value as the target duty cycle;

[0046] Each preset duty cycle value is determined by a preset on-time and a fixed rest time. The preset on-time is the total duration of the pulse signal in the high-level state within one cycle, and the fixed rest time is the total duration of the pulse signal in the low-level state within one cycle.

[0047] In one embodiment, the target charging mode is a third charging mode, and the target battery is controlled to charge according to the target charging parameters, including:

[0048] The constant current charging value in constant current charging mode is determined based on the product of the target charging rate and the rated capacity of the target battery.

[0049] The target battery is controlled to enter a constant current charging mode where the charging current is constant current charging value, and when the target battery is charged to the target charging cutoff voltage, the target battery is controlled to enter a constant voltage charging mode.

[0050] Secondly, this application also provides a sodium-ion battery charging control device, the device comprising:

[0051] The range determination module is used to obtain the operating temperature of the target battery and determine the target temperature range to which the operating temperature belongs.

[0052] The parameter determination module is used to determine the target charging parameters corresponding to the target temperature range based on the first mapping relationship and the second mapping relationship; wherein, the temperature range includes the extremely low temperature range, the sub-low temperature range, the transition temperature range and the normal temperature range with the temperature values ​​arranged in ascending order, and the target charging parameters include the target charging cut-off voltage and the target charging rate;

[0053] The mode determination module is used to determine the target charging mode corresponding to the target battery based on the target temperature range. The target charging mode is at least one of constant current charging mode, constant voltage charging mode and pulse charging mode.

[0054] The charging control module is used to control the target battery to charge according to the target charging parameters in the target charging mode.

[0055] The first mapping relationship represents the relationship between temperature range and charging cutoff voltage, and the second mapping relationship represents the relationship between temperature range and charging rate. The second mapping relationship includes a first rate-temperature relationship corresponding to the extremely low temperature region, a second rate-temperature relationship corresponding to the sub-low temperature region, a third rate-temperature relationship corresponding to the transition temperature region, and a fourth rate-temperature relationship corresponding to the normal temperature region. The first rate-temperature relationship is: the charging rate is a first preset rate. The second rate-temperature relationship is: the charging rate and operating temperature exhibit a third linear relationship with a third slope value and a third intercept. Both the third slope value and the third intercept are determined based on the temperature range value of the sub-low temperature region, the first preset rate, and the second preset rate. The second preset rate is greater than the first preset rate. The third rate-temperature relationship is: the charging rate and operating temperature exhibit a fourth linear relationship with a fourth slope value and a fourth intercept. Both the fourth slope value and the fourth intercept are determined based on the temperature range value of the transition temperature region, the second preset rate, and the third preset rate. The third preset rate is greater than the second preset rate. The fourth rate-temperature relationship is: the charging rate is any rate between the third preset rate and the maximum rate.

[0056] Thirdly, this application also provides an electronic device, including a memory and a processor, wherein the memory stores a computer program, and the processor executes the computer program to implement the method as described in any one of the first aspects.

[0057] Fourthly, this application also provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the method as described in any one of the first aspects.

[0058] Fifthly, this application also provides a computer program product, including a computer program that, when executed by a processor, implements the method as described in any one of the first aspects.

[0059] The aforementioned sodium-ion battery charging control method, apparatus, electronic device, and storage medium acquire the operating temperature of the target battery and determine the target temperature range to which the operating temperature belongs; determine the target charging parameters corresponding to the target temperature range according to a first mapping relationship and a second mapping relationship; determine the target charging mode corresponding to the target battery based on the target temperature range; and control the target battery to charge according to the target charging parameters in the target charging mode. After determining the target temperature range of the target battery, this sodium-ion battery charging control method dynamically determines the target charging cut-off voltage and target charging rate corresponding to the target temperature range according to the first and second mapping relationships; and dynamically determines the charging mode of the sodium-ion battery according to different temperature ranges. This charging control method dynamically coordinates the cut-off voltage, charging rate, charging mode, and temperature during the charging process to reasonably adjust the charging mode and all charging parameters of the sodium-ion battery at different operating temperatures, thereby reducing the risk of sodium deposition in the sodium-ion battery and improving the battery's service life. Attached Figure Description

[0060] To more clearly illustrate the technical solutions in the embodiments of this application or related technologies, the drawings used in the description of the embodiments of this application or related technologies will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0061] Figure 1 A diagram illustrating the application environment of a sodium-ion battery charging control method in one embodiment;

[0062] Figure 2 This is a flowchart illustrating a sodium-ion battery charging control method in one embodiment;

[0063] Figure 3 This is a flowchart illustrating the steps for determining voltage parameters in one embodiment;

[0064] Figure 4 This is a flowchart illustrating the steps for determining the magnification parameter in one embodiment;

[0065] Figure 5 This is a flowchart illustrating the charging steps of a target battery in one embodiment.

[0066] Figure 6 This is a flowchart illustrating the step of determining the duty cycle in one embodiment;

[0067] Figure 7 This is a flowchart illustrating the charging step of controlling the target battery in another embodiment;

[0068] Figure 8This is a structural block diagram of a sodium-ion battery charging control device in one embodiment;

[0069] Figure 9 This is a diagram of the internal structure of an electronic device in one embodiment. Detailed Implementation

[0070] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0071] It should be noted that the terms "first," "second," etc., used in this application can be used to describe various elements, but these elements are not limited by these terms. These terms are only used to distinguish the first element from the second element. The terms "comprising" and "having," and any variations thereof, used in this application, are intended to cover non-exclusive inclusion. The term "multiple" used in this application refers to two or more. The term "and / or" used in this application refers to one of the embodiments, or any combination of multiple embodiments.

[0072] Sodium-ion batteries have received widespread attention in recent years for their abundant sodium resources, low cost, and electrochemical principles similar to lithium-ion batteries, particularly in energy storage, low-speed electric vehicles, and low-temperature environments. However, during low-temperature charging, the electrolyte viscosity of sodium-ion batteries increases, the sodium ion diffusion coefficient in the negative electrode solid phase decreases sharply, and concentration polarization increases significantly. This can easily lead to irreversible sodium dendrite growth, which in severe cases can puncture the separator and cause an internal short circuit.

[0073] Existing low-temperature charging control technologies are mainly divided into two categories. One is the rate reduction method, which limits the charging rate to below 0.1C at low temperatures. While this method can suppress sodium deposition, the charging time is extremely long, and it does not consider the differences in the safe voltage window at different temperatures, mechanically using the charging cutoff voltage (e.g., 3.95V), resulting in continued charging even when the negative electrode potential has entered the sodium deposition region. The other is the pulse charging method, which uses positive and negative pulse charging at low temperatures, utilizing the reverse pulse to strip away the initial sodium nuclei. This method improves the low-temperature charging acceptance capability to some extent. However, this approach also does not adaptively adjust the charging cutoff voltage according to temperature, still using 3.95V as the target voltage below -10℃. Although the reverse pulse can strip away some dendrites, continuous high-voltage charging will cause the dendrite regeneration rate to exceed the stripping rate, and long-term cycling still poses a safety risk.

[0074] Therefore, how to control the charging of sodium-ion batteries and reduce the growth of sodium dendrites has become an urgent technical problem to be solved.

[0075] To address the aforementioned problems, this application provides a sodium-ion battery charging control method. This method obtains the operating temperature of the target battery and determines the target temperature range to which the operating temperature belongs; it determines the target charging parameters corresponding to the target temperature range based on a first mapping relationship and a second mapping relationship; it determines the target charging mode corresponding to the target battery based on the target temperature range; and it controls the target battery to charge according to the target charging parameters under the target charging mode. This application, based on a pre-constructed first and second mapping relationship, limits the charging cutoff voltage in the extremely low temperature region, sub-low temperature region, transition temperature region, and normal temperature region, ensuring that the negative electrode potential is always not lower than 0V, preventing sodium dendrite formation and thus reducing sodium dendrite growth and the risk of sodium deposition. Furthermore, using different charging modes in different temperature ranges also reduces the risk of sodium deposition.

[0076] The sodium-ion battery charging control method provided in this application embodiment can be applied to, for example... Figure 1 The application environment shown includes a battery 101, a battery management system (BMS) 102, and various sensors 103. The BMS 102 is communicatively connected to both the battery 101 and each of the sensors 103. The sensors 103 include, but are not limited to, temperature sensors, voltage sensors, and current sensors. The temperature sensor acquires the operating temperature of the battery 101, the voltage sensor acquires the battery voltage, and the current sensor acquires the charging current. The BMS 102 obtains the battery's operating temperature from the temperature sensor, determines the target temperature range to which the operating temperature belongs, and controls the charging of the battery 101 based on the target temperature range, a first mapping relationship, and a second mapping relationship.

[0077] In one exemplary embodiment, such as Figure 2 As shown, a sodium-ion battery charging control method is provided, which is applied to... Figure 1 The following steps are used as an example of the battery management system in the example, including steps S201 to S204.

[0078] Step 201: Obtain the operating temperature of the target battery and determine the target temperature range to which the operating temperature belongs.

[0079] The temperature sensor collects the operating temperature of the target battery at a preset sampling frequency and transmits the operating temperature to the battery management system. The battery management system has multiple temperature ranges preset, and after acquiring the operating temperature, it determines the target temperature range to which the operating temperature belongs.

[0080] For example, the battery management system pre-sets four temperature ranges, including: a temperature range below -15°C, a temperature range from -15°C to -5°C, a temperature range from -5°C to 10°C, and a temperature range above 10°C. If the operating temperature of the target battery is -10°C, then the target temperature range is determined to be the temperature range from -15°C to -5°C; if the operating temperature of the target battery is 20°C, then the target temperature range is determined to be the temperature range above 10°C.

[0081] Step 202: Determine the target charging parameters corresponding to the target temperature range based on the first mapping relationship and the second mapping relationship.

[0082] The first mapping relationship represents the relationship between temperature ranges and charging cut-off voltages, while the second mapping relationship represents the relationship between temperature ranges and charging rates. Temperature ranges include an extremely low temperature zone, a sub-low temperature zone, a transitional temperature zone, and a normal temperature zone, with temperatures increasing sequentially. Target charging parameters include the target charging cut-off voltage and the target charging rate. In practical applications, the temperature range below -15°C is considered the extremely low temperature zone, the temperature range from -15°C to -5°C is the sub-low temperature zone, the temperature range from -5°C to 10°C is the transitional temperature zone, and the temperature range above 10°C is the normal temperature zone. In the first mapping relationship, different temperature ranges correspond to different charging cut-off voltages; in the second mapping relationship, different temperature ranges correspond to different charging rates.

[0083] For example, when the target battery's operating temperature is in the sub-low temperature range, the target charging cutoff voltage can be determined based on the charging cutoff voltage corresponding to the sub-low temperature range in the first mapping relationship; the target charging rate can be determined based on the charging rate corresponding to the sub-low temperature range in the second mapping relationship. Similarly, when the target battery's operating temperature is in the room temperature range, the target charging cutoff voltage can be determined based on the charging cutoff voltage corresponding to the room temperature range in the first mapping relationship; the target charging rate can be determined based on the charging rate corresponding to the room temperature range in the second mapping relationship.

[0084] Step 203: Based on the target temperature range, determine the target charging mode corresponding to the target battery.

[0085] The target charging mode is at least one of constant current charging mode, constant voltage charging mode, and pulse charging mode. Constant current charging mode refers to a charging mode in which the charging current remains constant during the charging process, and the voltage gradually increases as the battery capacity increases; constant voltage charging mode refers to a charging mode in which the charging voltage remains constant during the charging process, and the charging current gradually decreases; pulse charging mode refers to a charging mode in which the battery is charged with intermittent pulse current or pulse voltage, and charging and pausing alternately.

[0086] The correspondence between different temperature ranges and different charging modes is pre-defined. After determining the target temperature range to which the target battery's operating temperature belongs, the target charging mode corresponding to the target temperature range is determined based on the above correspondence.

[0087] For example, the extremely low temperature region corresponds to a constant current charging mode, the sub-low temperature region corresponds to a charging mode combining pulse charging and constant voltage charging, and the transition temperature region and the normal temperature region correspond to a charging mode combining constant current charging and constant voltage charging. When the sub-low temperature region is the target temperature range, the target charging mode can be determined to be a charging mode combining pulse charging and constant voltage charging based on the above correspondence. When the normal temperature region is the target temperature range, the target charging mode can be determined to be a charging mode combining constant current charging and constant voltage charging based on the above correspondence.

[0088] Step 204: In the target charging mode, control the target battery to charge according to the target charging parameters.

[0089] In constant current charging mode, the target battery is controlled to undergo constant current charging according to the target charging rate. In a charging mode combining pulse charging and constant voltage charging, the peak current of the pulse signal is determined according to the target charging rate, and the target battery is charged according to the peak current. When the battery voltage reaches the target charging cutoff voltage, the target battery is controlled to undergo constant voltage charging according to the target charging cutoff voltage. Similarly, different target charging parameters are used to control the charging of the target battery in different target charging modes.

[0090] In the above embodiments, the operating temperature of the target battery is obtained, and the target temperature range to which the operating temperature belongs is determined; according to the first mapping relationship and the second mapping relationship, the target charging parameters corresponding to the target temperature range are determined; based on the target temperature range, the target charging mode corresponding to the target battery is determined; in the target charging mode, the target battery is controlled to charge according to the target charging parameters. This sodium-ion battery charging control method, after determining the target temperature range of the target battery, dynamically determines the target charging cut-off voltage and target charging rate corresponding to the target temperature range according to the first mapping relationship and the second mapping relationship; and dynamically determines the charging mode of the sodium-ion battery according to different temperature ranges. This charging control method dynamically coordinates the cut-off voltage, charging rate, charging mode, and temperature during the charging process to reasonably adjust the charging mode and all charging parameters of the sodium-ion battery at different operating temperatures, thereby reducing the risk of sodium deposition in the sodium-ion battery and improving the battery's service life.

[0091] In an exemplary embodiment, the first mapping relationship includes a first voltage-temperature relationship corresponding to the extremely low temperature region, a second voltage-temperature relationship corresponding to the sub-low temperature region, a third voltage-temperature relationship corresponding to the transition temperature region, and a fourth voltage-temperature relationship corresponding to the normal temperature region. The first voltage-temperature relationship is that the charging cut-off voltage is a first preset voltage. The second voltage-temperature relationship is that the charging cut-off voltage and the operating temperature exhibit a first linear relationship with a first slope value and a first intercept, wherein both the first slope value and the first intercept are determined based on the temperature range value of the sub-low temperature region, the first preset voltage, and the second preset voltage, and the second preset voltage is greater than the first preset voltage. The third voltage-temperature relationship is that the charging cut-off voltage and the operating temperature exhibit a second linear relationship with a second slope value and a second intercept, wherein both the second slope value and the second intercept are determined based on the temperature range value of the transition temperature region, the second preset voltage, and the third preset voltage, and the third preset voltage is greater than the second preset voltage. The fourth voltage-temperature relationship is that the charging cut-off voltage is the third preset voltage.

[0092] In this embodiment of the application, the first mapping relationship is as follows:

[0093]

[0094] Where V_max is the charging cutoff voltage, a1 is the first preset voltage, a2 is the second preset voltage, a3 is the third preset voltage, T is the operating temperature, b1 is the upper temperature limit of the extremely low temperature region, b2 is the upper temperature limit of the sub-low temperature region, and b3 is the upper temperature limit of the transition temperature region. The first slope is... The first intercept is The second slope is The second intercept is .

[0095] When the operating temperature T is not greater than b1, the target temperature range is determined to be the extremely low temperature region, and the first preset voltage a1 is determined as the charging cutoff voltage V_max. When the operating temperature T is greater than b1 but not greater than b2, the target temperature range is determined to be the sub-low temperature region. A first slope and a first intercept are calculated based on the first preset voltage a1, the second preset voltage a2, the upper temperature limit b1, and the upper temperature limit b2. The charging cutoff voltage V_max is calculated based on the first slope, the operating temperature, and the first intercept. When the operating temperature T is greater than b2 but not greater than b3, the target temperature range is determined to be the transition temperature region. A second slope and a second intercept are calculated based on the second preset voltage a2, the third preset voltage a3, the upper temperature limit b2, and the upper temperature limit b3. The charging cutoff voltage V_max is calculated based on the second slope, the operating temperature, and the second intercept. When the operating temperature is greater than b3, the third preset voltage a3 is determined as the charging cutoff voltage V_max.

[0096] In one specific embodiment, a1 = 3.50V, a2 = 3.65V, a3 = 3.95V, b1 = -15℃, b2 = 5℃, b3 = 10℃. The first mapping relationship is as follows:

[0097]

[0098] In the above embodiments, the first mapping relationship includes a first voltage-temperature relationship corresponding to the extremely low temperature region, a second voltage-temperature relationship corresponding to the sub-low temperature region, a third voltage-temperature relationship corresponding to the transition temperature region, and a fourth voltage-temperature relationship corresponding to the normal temperature region. This application's embodiments pre-establish the first mapping relationship and limit the charging cutoff voltage in the extremely low temperature region, sub-low temperature region, transition temperature region, and normal temperature region. This ensures that the negative electrode potential of the target battery remains above 0V during charging, preventing sodium dendrite formation and thus reducing sodium dendrite growth and the risk of sodium deposition.

[0099] In an exemplary embodiment, the voltage parameter is set to any one of a first preset voltage, a second preset voltage, and a third preset voltage, such as... Figure 3 As shown, the process of determining voltage parameters may include the following steps 301 to 303:

[0100] Step 301: Set the temperature sampling range for determining the first preset voltage to the extremely low temperature region; set the temperature sampling range for determining the second preset voltage to the sub-low temperature region and the transition temperature region; set the temperature sampling range for determining the third preset voltage to the normal temperature region.

[0101] Step 302: Control multiple sample batteries to be charged at any temperature within the temperature sampling range and at different charging rates, and record the battery voltage of the sample battery when the negative electrode potential first drops to zero at each charging rate to obtain a voltage set.

[0102] Step 303: Calculate the median in the voltage set and determine the median as the voltage parameter.

[0103] In this embodiment, when the temperature sampling range is in the extremely low temperature region, multiple sample batteries are controlled to be charged at any temperature using different charging rates. At each charging rate, the battery voltage (the difference between the positive and negative electrode voltages) of the sample battery is recorded when the negative electrode potential first drops to zero, resulting in a voltage set. Since the median can represent the typical behavior of the battery and provide a symmetrical safety margin for the upper and lower limits of the safety range, statistical analysis is performed on the battery voltages in the voltage set to determine the median battery voltage, and the median is used to determine the first preset voltage.

[0104] Taking a temperature sampling range of T≤-15°C as an example, the sample battery is placed at -20°C and charged at different charging rates (0.05C~1.0C) at -20°C. The terminal voltage Vc corresponding to each charging rate (0.05C~1.0C) is recorded, thus obtaining a voltage set related to the terminal voltage Vc. The median of the statistical voltage set is 3.50V, so 3.50V is determined as the value of the first preset voltage a1.

[0105] When the temperature sampling range is in the sub-low temperature zone, transition temperature zone, or normal temperature zone, the second preset voltage a2 and the third preset voltage a3 are determined in accordance with the above method.

[0106] It's important to note that the battery should be allowed to reach thermal equilibrium at different temperatures before being charged at different rates. Thermal equilibrium refers to the state where the temperature of all parts of the battery matches the external ambient temperature. A battery is a complex multi-layered structure (positive electrode, separator, negative electrode, electrolyte). When placed from room temperature into a low-temperature (e.g., -20°C) constant-temperature chamber, the surface temperature drops rapidly, causing the battery casing to cool first. The internal temperature drops more slowly, meaning the central region of the battery needs a longer time to reach the set temperature. If testing is conducted before thermal equilibrium is reached, the actual battery temperature may be higher than the set temperature (e.g., set at -20°C, but the center temperature may only be -10°C), resulting in artificially inflated performance measurements that do not represent true low-temperature characteristics.

[0107] In some embodiments, different temperatures may include: -30℃, -20℃, -15℃, -10℃, -5℃, 0℃, 5℃, 10℃, 25℃, and different charging rates may include 0.05C to 1.0C.

[0108] In some embodiments, data as shown in Table 1 can be obtained based on records and statistical analysis:

[0109] Table 1

[0110]

[0111] Based on the data in Table 1, the first preset voltage can be determined to be 3.50V, the second preset voltage to be 3.65V, and the third preset voltage to be 3.95V.

[0112] In some embodiments, the battery voltage can be determined by linear interpolation for the temperature between every two temperatures in the experiment, thereby forming a dynamic charging cutoff voltage function that changes continuously with temperature.

[0113] In the above embodiments, experiments were conducted at different temperatures and charging rates within different temperature sampling ranges. This allowed for the acquisition of the battery voltage of the sample battery at each charging rate when the negative electrode potential first dropped to zero. This provided data support for setting the charging cutoff voltage, ensuring that charging in different temperature zones would prevent the negative electrode voltage from entering the sodium deposition zone, thereby reducing the risk of sodium deposition.

[0114] In an exemplary embodiment, the second mapping relationship includes a first rate-temperature relationship corresponding to the extremely low temperature region, a second rate-temperature relationship corresponding to the sub-low temperature region, a third rate-temperature relationship corresponding to the transition temperature region, and a fourth rate-temperature relationship corresponding to the normal temperature region. The first rate-temperature relationship is: the charging rate is a first preset rate. The second rate-temperature relationship is: the charging rate and operating temperature exhibit a third linear relationship with a third slope value and a third intercept, wherein both the third slope value and the third intercept are determined based on the temperature range value of the sub-low temperature region, the first preset rate, and the second preset rate, and the second preset rate is greater than the first preset rate. The third rate-temperature relationship is: the charging rate and operating temperature exhibit a fourth linear relationship with a fourth slope value and a fourth intercept, wherein both the fourth slope value and the fourth intercept are determined based on the temperature range value of the transition temperature region, the second preset rate, and the third preset rate, and the third preset rate is greater than the second preset rate. The fourth rate-temperature relationship is: the charging rate is any rate between the third preset rate and the maximum rate.

[0115] In this embodiment of the application, the second mapping relationship is as follows:

[0116]

[0117] Where Cr is the charging rate, c1 is the first preset rate, c2 is the second preset rate, c3 is the third preset rate, T is the operating temperature, b1 is the upper limit of the extremely low temperature region, b2 is the upper limit of the sub-low temperature region, and b3 is the upper limit of the transition temperature region. The third slope is The third intercept is The fourth slope is The fourth intercept is .

[0118] When the operating temperature T is not greater than b1, the target temperature range is determined to be the extremely low temperature region, and the first preset rate c1 is determined as the charging rate Cr. When the operating temperature T is greater than b1 but not greater than b2, the target temperature range is determined to be the sub-low temperature region. A third slope and a third intercept are calculated based on the first preset rate c1, the second preset rate c2, the upper temperature limit b1, and the upper temperature limit b2. The charging rate Cr is calculated based on the third slope, the operating temperature, and the third intercept. When the operating temperature T is greater than b2 but not greater than b3, the target temperature range is determined to be the transition temperature region. A fourth slope and a fourth intercept are calculated based on the second preset rate c2, the third preset rate c3, the upper temperature limit b2, and the upper temperature limit b3. The charging rate Cr is calculated based on the fourth slope, the operating temperature, and the fourth intercept. When the operating temperature is greater than b3, the third preset rate c3 and the maximum rate 1.0C are selected as the charging rate Cr.

[0119] In some embodiments, c1=0.1C, c2=0.2C, c3=0.5C, b1=-15℃, b2=5℃, and b3=10℃.

[0120] In the above embodiments, by pre-establishing a second mapping relationship, the charging rate in the extremely low temperature region, sub-low temperature region, transition temperature region, and normal temperature region can be limited. By reducing the charging rate, sodium deposition can be suppressed, thereby reducing the risk of sodium deposition.

[0121] In an exemplary embodiment, the magnification parameter is set to any one of a first preset magnification, a second preset magnification, and a third preset magnification, such as... Figure 4 As shown, the process of determining the magnification parameter may include the following steps:

[0122] Step 401: Set the temperature sampling range used to determine the first preset magnification to the extremely low temperature zone; set the temperature sampling range used to determine the second preset magnification to the sub-low temperature zone and the transition temperature zone; set the temperature sampling range used to determine the third preset magnification to the normal temperature zone.

[0123] Step 402: Control multiple sample batteries to be charged at any temperature within the temperature sampling range and at different charging rates, and record the critical rate of the sample battery when the negative electrode potential first drops to zero at each charging rate to obtain the rate set.

[0124] Step 403: Calculate the median in the set of multiples and determine the median as the multiple parameter.

[0125] In this embodiment, when the temperature sampling range is in the extremely low temperature region, multiple sample batteries are controlled to be charged at different charging rates at any temperature. The critical charging rate at which the negative electrode potential of the sample battery first drops to zero is recorded for each charging rate, resulting in a set of charging rates. Since the median can represent the typical behavior of the battery and provide a symmetrical safety margin for the upper and lower limits of the safety range, statistical analysis is performed on the critical rates in the set of charging rates to determine the median of the critical rates, and the value of the first preset charging rate c1 is determined based on the median.

[0126] Taking a temperature sampling range of T <= -15°C as an example, the sample battery was placed at -20°C and charged at different charging rates (0.05C to 1.0C) at -20°C. The critical charging rate Ic of the sample battery when the negative electrode voltage was 0 was recorded, thus obtaining a set of charging rates. The median of the set of charging rates was 0.11C, and 0.1C was determined as the value of the first preset charging rate c1. It should be noted that using 0.1C as the first preset charging rate is not only convenient for calculation, but also safer as it is slightly smaller than the median.

[0127] When the temperature sampling range is in the sub-low temperature zone, transition temperature zone, or normal temperature zone, the second preset magnification c2 and the third preset magnification c3 are determined in accordance with the above method.

[0128] In some embodiments, different temperatures may include: -30℃, -20℃, -15℃, -10℃, -5℃, 0℃, 5℃, 10℃, 25℃, and different charging rates may include 0.05C to 1.0C.

[0129] In some embodiments, data as shown in Table 2 can be obtained based on records and statistical analysis:

[0130] Table 2

[0131]

[0132] Based on the data in Table 2, the first preset multiplier can be determined to be 0.1C, the second preset multiplier to be 0.2C, and the third preset multiplier to be 0.5C.

[0133] In some embodiments, voltage parameters and rate parameters are jointly verified to determine whether the preset voltage and preset rate determined in the above embodiments are reasonable. The data obtained after verification are shown in Table 3.

[0134] Table 3

[0135]

[0136] The data in the table shows that in the extremely low temperature region, the first charging rate is 0.1C, the first preset voltage is 3.50V, and the lowest negative electrode potential is between 0.02V and 0.08V, meaning the negative electrode potential is never lower than 0V. Dendrite formation is impossible, thus reducing the risk of sodium precipitation. Similarly, in the sub-low temperature region, the transition temperature region, and the normal temperature region, the negative electrode potential is never lower than 0V. Therefore, the first preset voltage, second preset voltage, third preset voltage, first preset rate, second preset rate, and third preset rate determined in the above embodiments are all reasonable, and the risk of sodium precipitation is low.

[0137] In the above embodiments, experiments were conducted at different temperatures and charging rates within different temperature sampling ranges. This allowed for the determination of the critical charging rate of the sample battery at which the negative electrode potential first dropped to zero at each charging rate. This provided data support for setting the charging rate, and thus, charging in different temperature zones effectively suppressed sodium deposition.

[0138] In an exemplary embodiment, step S203, determining the target charging mode corresponding to the target battery based on the target temperature range, may include the following steps S2031 to S2033:

[0139] Step S2031: When the target temperature range is in the extremely low temperature range, the target charging mode is determined to be the first charging mode, which is the constant current charging mode.

[0140] After obtaining the operating temperature, if the target temperature range falls within the extremely low temperature zone, the target charging mode is determined to be constant current charging mode, meaning the charging current remains constant throughout the charging process. Understandably, the charging rate does not decrease as the temperature further drops, ensuring normal charging of the target battery at extremely low temperatures while avoiding excessively long charging times due to insufficient current.

[0141] Step S2032: When the target temperature range is in the sub-low temperature range, the target charging mode is determined to be the second charging mode. The second charging mode is a charging mode that combines pulse charging mode and constant voltage charging mode. The pulse charging mode is to charge the target battery with pulse signals.

[0142] After obtaining the operating temperature, if the target temperature range to which the operating temperature belongs is the sub-low temperature range, then the target charging mode is determined to be a combination of pulse charging mode and constant voltage charging mode. That is, during the charging process, the target battery is first charged with a pulse signal, and after the battery voltage of the target battery reaches the charging cutoff voltage, the charging voltage is kept constant.

[0143] Understandably, polarization accumulates more rapidly at low temperatures. By exciting the embedding capability with a positive pulse and extending the fixed settling time, concentration polarization can be fully dissipated. Furthermore, the negative electrode voltage is dynamically monitored to ensure that it does not enter the sodium deposition region. In this way, a strict voltage threshold and sufficient settling time can effectively suppress dendrite growth.

[0144] Positive pulse: A brief application of a high current stimulates the surface reaction of the negative electrode, promoting sodium ion insertion. Resting: The current is zero, concentration polarization is partially eliminated, the sodium ion concentration at the interface recovers, and the terminal voltage decreases. Repeated cycles allow the battery to operate consistently in a lower average polarization state.

[0145] Step S2033: If the target temperature range is in the transition temperature range or the normal temperature range, determine the target charging mode as the third charging mode. The third charging mode is a charging mode that combines constant current charging mode and constant voltage charging mode.

[0146] After obtaining the operating temperature, if the target temperature range to which the operating temperature belongs is the transition temperature range or the normal temperature range, then the target charging mode is determined to be a combination of constant current charging mode and constant voltage charging mode. That is, during the charging process, the charging current is kept constant first, and after the target battery voltage reaches the preset voltage, the charging voltage is kept constant.

[0147] Understandably, as the temperature rises and polarization weakens, the charging cutoff voltage can be gradually increased, allowing the battery to enter a constant voltage charging mode.

[0148] In the above embodiments, different target temperature ranges correspond to different target charging modes, which can make the charging mode more suitable for the operating temperature of the target battery, reduce the risk of sodium precipitation, and reduce the problems caused by sodium dendrite growth.

[0149] In an exemplary embodiment, the target charging mode is a first charging mode. The above embodiment of "controlling the target battery to charge according to the target charging parameters" may include: controlling the target battery to charge at a target charging rate and in a constant current charging mode, and controlling the target battery to stop charging when it reaches the target charging cutoff voltage.

[0150] When the target temperature range is the extremely low temperature region and the target charging mode is constant current charging mode, the target charging cutoff voltage corresponding to the extremely low temperature region is determined according to the first mapping relationship, and the target charging rate corresponding to the extremely low temperature region is determined according to the second mapping relationship. Then, the target charging rate is used to charge the battery, and this target charging rate is maintained constant throughout the charging process. The battery voltage of the target battery gradually increases with capacity growth, and charging stops when the target battery reaches the target charging cutoff voltage.

[0151] For example, the target charging rate corresponding to the extremely low temperature region is determined to be 0.1C, and the target charging cutoff voltage is 3.50V; then, the target battery is charged at 0.1C. During the charging process, the charging rate is kept constant at 0.1C until the target battery is charged to 3.50V and charging is stopped; constant voltage charging mode is not allowed.

[0152] In the above embodiments, even with extremely low current constant voltage charging at extremely low temperatures, the battery will remain at a high potential for a long time, and the negative electrode potential will remain below 0V, leading to dendrite accumulation. Directly prohibiting constant voltage charging can maximize the safety margin and reduce the risk of sodium dendrite growth.

[0153] In an exemplary embodiment, when the target charging mode is a second charging mode, such as... Figure 5 As shown, in the above embodiment, "controlling the target battery to charge according to the target charging parameters" may include the following steps 501 to 504:

[0154] Step 501: Determine the average current of the pulse signal based on the target charging rate and the rated capacity of the target battery.

[0155] When the target temperature range is the sub-low temperature region and the target charging mode is a combination of pulse charging mode and constant voltage charging, the target charging cutoff voltage corresponding to the sub-low temperature region is determined according to the first mapping relationship, and the target charging rate corresponding to the sub-low temperature region is determined according to the second mapping relationship.

[0156] The average current of the pulse signal can be determined according to I. avg =Cr(T) * Battery rated capacity is determined, where I avg The average current is Cr(T), and the target charging rate is determined based on the operating temperature T and the second mapping relationship.

[0157] Step 502: Determine the peak current based on the average current and the target duty cycle of the pulse signal.

[0158] The peak current and average current of the pulse signal satisfy the following relationship: I avg =I peak ×D, where I avg For the average current, I peak Let be the peak current and D be the target duty cycle. After determining the average current and the target duty cycle, the peak current can be calculated using this formula.

[0159] Step 503: Charge the target battery with a pulse signal of peak current and target duty cycle and monitor the battery voltage of the target battery.

[0160] The target battery is charged using the pulse signal with the above peak current and duty cycle. During the charging process, the battery voltage is monitored in the following way: the voltage valley value V_min (the voltage at the end of the interval) within the pulse cycle is monitored in real time; when the voltage valley value reaches the warning voltage, it is determined that the next positive pulse will touch the charging cutoff voltage, and the main pulse stage is exited in advance, and the charging is switched to 0.05C trickle constant voltage charging.

[0161] The warning voltage is V_max-ΔV (ΔV is 0.02V to 0.05V), where V_max is the predetermined target charging cutoff voltage.

[0162] Step 504: When the battery voltage reaches the target charging cutoff voltage, control the target battery to enter the constant voltage charging mode at the target charging cutoff voltage.

[0163] After switching to trickle charging, monitor whether the battery voltage reaches the target charging cutoff voltage. When the battery voltage reaches the target charging cutoff voltage, control the target battery to enter constant voltage charging mode at the target charging cutoff voltage.

[0164] In the above embodiments, charging is performed in the sub-low temperature region using a unidirectional pulse + long rest + dynamic voltage reduction method. By allowing sufficient rest to restore polarization, combined with a stricter charging cutoff voltage, the dendrite growth rate can be kept extremely low, thereby improving the cycle life of the battery.

[0165] In one exemplary embodiment, such as Figure 6 As shown, this application may also include a process for determining the target duty cycle of the pulse signal, such as steps 601 to 603:

[0166] Step 601: Select an operating temperature belonging to the sub-low temperature region, and determine the target charging rate and target charging cut-off voltage at that operating temperature.

[0167] Step 602: Using multiple preset duty cycle values ​​and target charging rates, control the sample battery to charge until the battery voltage reaches the target charging cutoff voltage, and record the charging amount after each charge.

[0168] Step 603: Determine the maximum value among all charging capacities, and use the preset duty cycle value corresponding to the maximum value as the target duty cycle.

[0169] Each preset duty cycle value is determined by a preset on-time and a fixed rest time. The on-time is the total duration of the pulse signal in the high-level state within one cycle, and the preset rest time is the total duration of the pulse signal in the low-level state within one cycle.

[0170] In one specific embodiment, an operating temperature in the sub-low temperature range is selected, and the corresponding target charge rate C at that operating temperature is determined.目标 and target charging cutoff voltage V 目标 Furthermore, multiple preset duty cycles are set, wherein each preset duty cycle D i Both are determined by a fixed settling time T1 and a preset conduction time T2, i.e., D i =T1 / (T1+T2), controlling the sample battery at the charging rate C i and different preset duty cycles D i Charge the battery until it reaches the target charging cutoff voltage V. 目标 Record all different preset duty cycles D i The amount of charge Q at the end of the charging process i Determine the maximum value Q among all charging capacities. max With the maximum value Q max The corresponding preset duty cycle value is the target duty cycle.

[0171] In this embodiment of the application, the process of determining the fixed static time is as follows.

[0172] At low temperatures, the diffusion coefficient of sodium ions in the negative electrode solid phase decreases sharply, leading to a rapid accumulation of concentration polarization. When the current is interrupted, the ion concentration gradient on the electrode surface requires a certain amount of time to recover; this timescale is characterized by the diffusion relaxation time τ. .

[0173] Where τ is the diffusion relaxation time, i.e. the time required for the ion concentration to recover to the equilibrium state; L is the characteristic diffusion length of the negative electrode active material particles. denoted as the diffusion coefficient of sodium ions. Under equilibrium conditions, the concentrations of anions and cations within the solution and near the electrode surface do not change with time; there is no net migration or diffusion of ions, and their random thermal motion macroscopically cancels each other out.

[0174] Can be set , where k=[2,3].

[0175] The diffusion relaxation time τ is typically defined as the time required for the concentration gradient to dissipate to 1 / e (approximately 37%) of its initial value. This means that after 1 τ, 37% of the concentration gradient remains; after 2 τ, 13.5% remains; and after 3 τ, 5% remains.

[0176] In practical applications, it is usually not necessary for the concentration gradient to dissipate to 0% (which would take a long time and be inefficient); it is sufficient to dissipate it to a level that will not significantly affect the next pulse. Based on the above dissipation conditions, k can be taken as 2 to 3.

[0177] For example, the measured diffusion coefficient of the hard carbon anode in a sodium-ion battery at low temperatures is typically in the range of... m² / s, but with smaller particle size (2~5μm). Taking L=3μm, =2×10⁻¹³m² / s, which can be calculated as follows:

[0178]

[0179] The fixed settling time T2 should satisfy the following relationship:

[0180]

[0181] For ease of use in engineering, the fixed settling time T2 is set to 10s.

[0182] In one exemplary embodiment, the target charging mode is a third charging mode, such as... Figure 7 As shown, in the above embodiment, "controlling the target battery to charge according to the target charging parameters" may include the following steps:

[0183] Step 701: Determine the constant current charging value in constant current charging mode based on the product of the target charging rate and the rated capacity of the target battery.

[0184] The constant current charging value can be determined according to the following relationship I avg =Cr(T) * Battery rated capacity. Where, I avg For constant current charging value, Cr(T) is the target charging rate determined based on operating temperature and the second mapping relationship.

[0185] Step 702: Control the target battery to enter the constant current charging mode where the charging current is constant current charging value, and control the target battery to enter the constant voltage charging mode when the target battery is charged to the target charging cutoff voltage.

[0186] For example, the operating temperature is 0°C, and the target temperature range to which the operating temperature falls is the transition temperature zone. Based on the operating temperature and the first mapping relationship, the target charging cutoff voltage is determined to be 3.75V, and the target charging rate is 0.5C. The target battery is charged using a constant current charging value corresponding to the target charging rate. As the battery voltage gradually increases during charging, when the target battery is charged to 3.75V, the charging mode is switched from constant current charging mode to constant voltage charging mode, that is, the target battery is charged using a constant voltage of 3.75V until the charging current is less than a preset current threshold (such as 0.05C), at which point charging stops.

[0187] For example, if the operating temperature is 25°C and the target temperature range is the room temperature range, and the target charging cutoff voltage is determined to be 3.95V based on the operating temperature and the first mapping relationship, and the target charging rate is 1.0C, then the target battery is charged using a constant current charging value corresponding to the target charging rate. When the target battery is charged to 3.95V, it is charged using a constant voltage of 3.95V until the charging current is less than a preset current threshold (e.g., 0.05C), at which point charging stops.

[0188] Based on the above embodiments, the following conclusions can be drawn: In the extremely low temperature region, the battery state is characterized by extremely slow ion diffusion and extremely high battery polarization. Based on this battery state, a pure constant current charging method is adopted, a low-voltage cutoff condition is set, and constant voltage charging is prohibited. In this way, the negative electrode potential is always greater than or equal to 0V, which allows full utilization of the maximum safe charging rate allowed under this temperature condition.

[0189] In the sub-low temperature range, the battery's ion diffusion rate remains slow, but polarization and concentration imbalance issues can be resolved. Based on this battery state, pulse charging combined with a fixed resting time is employed, while voltage is monitored in real time throughout the process. In this way, the interfacial concentration polarization can be dissipated during the resting process, and the charging conditions can be controlled by dynamic parameter intervention. This allows the electrode activity to be stimulated by the pulse peak current, while maintaining the average operating current within a safe range, thus achieving a higher usable capacity.

[0190] In the transition temperature range, the battery's ion diffusion capacity increases, and charging polarization gradually weakens. Based on this battery state, a combination of constant current and constant voltage charging is employed, with the charging voltage dynamically adjusted according to the ambient temperature rise. This dynamic adaptation of the voltage parameters to the safety boundary corresponding to the temperature allows for the gradual release of battery capacity, avoiding capacity waste.

[0191] At room temperature, the battery exhibits normal electrochemical characteristics. Based on this battery state, a combination of constant current and constant voltage charging is employed. This allows for safety control through current limiting during the constant voltage phase, achieving full charging and also supporting fast charging.

[0192] Table 4

[0193]

[0194] In the above embodiments, using a higher charging cutoff voltage in the transition temperature zone and the normal temperature zone can shorten the charging time and improve the charging efficiency.

[0195] In one exemplary embodiment, a sodium-ion battery charging control method is provided, which is applied to... Figure 1 Taking the battery management system in the example, the following steps are included:

[0196] Step 1: Obtain the operating temperature of the target battery and determine the target temperature range to which the operating temperature belongs.

[0197] Step 2: Determine the target charging parameters corresponding to the target temperature range based on the first mapping relationship and the second mapping relationship.

[0198] The target charging parameters include the target charging cutoff voltage and the target charging rate.

[0199] The first mapping relationship includes the first voltage-temperature relationship corresponding to the extremely low temperature region, the second voltage-temperature relationship corresponding to the sub-low temperature region, the third voltage-temperature relationship corresponding to the transition temperature region, and the fourth voltage-temperature relationship corresponding to the normal temperature region.

[0200] The second mapping relationship includes the first multiplier temperature relationship corresponding to the extremely low temperature region, the second multiplier temperature relationship corresponding to the sub-low temperature region, the third multiplier temperature relationship corresponding to the transition temperature region, and the fourth multiplier temperature relationship corresponding to the normal temperature region.

[0201] Step 3: If the target temperature range is in the extremely low temperature range, determine the target charging mode as the first charging mode.

[0202] The first charging mode is the constant current charging mode.

[0203] Step 4: In the first charging mode, control the target battery to charge at the target charging rate and in constant current charging mode, and control the target battery to stop charging when it reaches the target charging cutoff voltage.

[0204] Step 5: If the target temperature range is in the sub-low temperature range, determine the target charging mode as the second charging mode.

[0205] The second charging mode is a combination of pulse charging mode and constant voltage charging mode.

[0206] Step 6: In the second charging mode, determine the average current of the pulse signal based on the target charging rate and the rated capacity of the target battery; determine the peak current based on the average current and the target duty cycle of the pulse signal; charge the target battery with a pulse signal of peak current amplitude and target duty cycle and monitor the battery voltage of the target battery; when the battery voltage reaches the target charging cutoff voltage, control the target battery to enter the constant voltage charging mode at the target charging cutoff voltage.

[0207] Step 7: If the target temperature range falls within the transitional temperature range or the normal temperature range, determine the target charging mode as the third charging mode.

[0208] The third charging mode is a combination of constant current charging mode and constant voltage charging mode.

[0209] Step 8: Determine the constant current charging value in constant current charging mode based on the product of the target charging rate and the rated capacity of the target battery; control the target battery to enter constant current charging mode with constant current charging current, and control the target battery to enter constant voltage charging mode when the target battery is charged to the target charging cutoff voltage.

[0210] Based on the pre-constructed first and second mapping relationships, the embodiments of this application limit the charging cutoff voltage in the extremely low temperature region, sub-low temperature region, transition temperature region and normal temperature region, so that the negative electrode potential is always not lower than 0V, and sodium dendrites have no conditions for formation. Therefore, sodium dendrite growth can be reduced and the risk of sodium precipitation can be reduced. Furthermore, different charging modes are used in different temperature ranges, which can also reduce the risk of sodium precipitation.

[0211] It should be understood that although the steps in the flowcharts of the embodiments described above are shown sequentially according to the arrows, these steps are not necessarily executed in the order indicated by the arrows. Unless explicitly stated herein, there is no strict order restriction on the execution of these steps, and they can be executed in other orders. Moreover, at least some steps in the flowcharts of the embodiments described above may include multiple steps or multiple stages. These steps or stages are not necessarily completed at the same time, but can be executed at different times. The execution order of these steps or stages is not necessarily sequential, but can be performed alternately or in turn with other steps or at least some of the steps or stages in other steps. It is understood that the steps in different embodiments can be freely combined as needed, and all non-contradictory solutions formed by such combinations are within the scope of protection of this application.

[0212] Based on the same inventive concept, this application also provides a sodium-ion battery charging control device for implementing the sodium-ion battery charging control method described above. The solution provided by this device is similar to the solution described in the above method; therefore, the specific limitations in one or more embodiments of the sodium-ion battery charging control device provided below can be found in the limitations of the sodium-ion battery charging control method described above, and will not be repeated here.

[0213] In one exemplary embodiment, such as Figure 8 A sodium-ion battery charging control device is provided, the device comprising:

[0214] The range determination module 801 is used to obtain the operating temperature of the target battery and determine the target temperature range to which the operating temperature belongs.

[0215] The parameter determination module 802 is used to determine the target charging parameters corresponding to the target temperature range according to the first mapping relationship and the second mapping relationship; wherein, the temperature range includes the extremely low temperature zone, the sub-low temperature zone, the transition temperature zone and the normal temperature zone with the temperature values ​​arranged in ascending order, and the target charging parameters include the target charging cut-off voltage and the target charging rate;

[0216] The mode determination module 803 is used to determine the target charging mode corresponding to the target battery based on the target temperature range. The target charging mode is at least one of constant current charging mode, constant voltage charging mode and pulse charging mode.

[0217] The charging control module 804 is used to control the target battery to charge according to the target charging parameters in the target charging mode.

[0218] The first mapping relationship represents the relationship between temperature range and charging cutoff voltage, and the second mapping relationship represents the relationship between temperature range and charging rate. The second mapping relationship includes the first rate-temperature relationship corresponding to the extremely low temperature region, the second rate-temperature relationship corresponding to the sub-low temperature region, the third rate-temperature relationship corresponding to the transition temperature region, and the fourth rate-temperature relationship corresponding to the normal temperature region.

[0219] The first rate-temperature relationship is: the charging rate is the first preset rate;

[0220] The second rate-temperature relationship is as follows: the charging rate and operating temperature exhibit a third linear relationship with a third slope value and a third intercept. The third slope value and the third intercept are both determined based on the temperature range value of the sub-low temperature region, the first preset rate and the second preset rate, and the second preset rate is greater than the first preset rate.

[0221] The third rate-temperature relationship is as follows: the charging rate and operating temperature exhibit a fourth linear relationship with the fourth slope value and the fourth intercept. The fourth slope value and the fourth intercept are both determined based on the temperature range value of the transition temperature zone, the second preset rate, and the third preset rate. The third preset rate is greater than the second preset rate.

[0222] The fourth rate-temperature relationship is: the charging rate is any rate between the third preset rate and the maximum rate.

[0223] It should be noted that each module in the above-mentioned sodium-ion battery charging control device can execute the above-described method embodiments, and their implementation principles and technical effects are similar, so they will not be described again here.

[0224] Each module in the aforementioned sodium-ion battery charging control device can be implemented entirely or partially through software, hardware, or a combination thereof. These modules can be embedded in the processor of the electronic device in hardware form or independent of it, or stored in the memory of the electronic device in software form, so that the processor can call and execute the corresponding operations of each module.

[0225] In one exemplary embodiment, an electronic device is provided, which may be a battery management system, and its internal structure diagram may be as follows: Figure 9 As shown, this electronic device includes a processor, memory, input / output (I / O) interfaces, and a communication interface. The processor, memory, and I / O interfaces are connected via a system bus, and the communication interface is also connected to the system bus via the I / O interfaces. The processor provides computational and control capabilities. The memory includes non-volatile storage media and internal memory. The non-volatile storage media stores the operating system, computer programs, and a database. The internal memory provides an environment for the operation of the operating system and computer programs stored in the non-volatile storage media. The database stores sodium-ion battery charging control data. The I / O interfaces are used for information exchange between the processor and external devices. The communication interface is used for communication with external terminals via a network connection. When the computer program is executed by the processor, it implements a sodium-ion battery charging control method.

[0226] Those skilled in the art will understand that Figure 9 The structure shown is merely a block diagram of a portion of the structure related to the present application and does not constitute a limitation on the electronic device to which the present application is applied. The specific electronic device may include more or fewer components than shown in the figure, or combine certain components, or have different component arrangements.

[0227] In one exemplary embodiment, a non-transitory computer-readable storage medium including instructions is also provided, such as a memory including instructions that can be executed by a processor of an electronic device to perform the above-described method. For example, the non-transitory computer-readable storage medium may be a ROM, random access memory (RAM), CD-ROM, magnetic tape, floppy disk, and optical data storage device, etc.

[0228] In one exemplary embodiment, a computer program product is also provided, which, when executed by a processor, can implement the above-described methods. The computer program product includes one or more computer instructions. When these computer instructions are loaded and executed on a computer, some or all of the above-described methods can be implemented, wholly or partially, according to the processes or functions described in the embodiments of this application.

[0229] It should be noted that the user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data used for analysis, data stored, data displayed, etc.) involved in this application are all information and data authorized by the user or fully authorized by all parties, and the collection, use and processing of the relevant data must comply with relevant regulations.

[0230] Those skilled in the art will understand that all or part of the processes in the methods of the above embodiments can be implemented by a computer program instructing related hardware. The computer program can be stored in a non-volatile computer-readable storage medium, and when executed, it can include the processes of the embodiments of the above methods. Any references to memory, databases, or other media used in the embodiments provided in this application can include at least one of non-volatile memory and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetic random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. By way of illustration and not limitation, RAM can take many forms, such as Static Random Access Memory (SRAM) or Dynamic Random Access Memory (DRAM). The databases involved in the embodiments provided in this application may include at least one type of relational database and non-relational database. Non-relational databases may include, but are not limited to, blockchain-based distributed databases. The processors involved in the embodiments provided in this application may be general-purpose processors, central processing units, graphics processing units, digital signal processors, programmable logic devices, quantum computing-based data processing logic devices, artificial intelligence (AI) processors, etc., and are not limited to these.

[0231] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this application.

[0232] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of this patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this application should be determined by the appended claims.

Claims

1. A method for controlling the charging of a sodium-ion battery, characterized in that, The method includes: Obtain the operating temperature of the target battery and determine the target temperature range to which the operating temperature belongs; Based on the first mapping relationship and the second mapping relationship, the target charging parameters corresponding to the target temperature range are determined; wherein, the temperature range includes an extremely low temperature zone, a sub-low temperature zone, a transition temperature zone and a normal temperature zone with the temperature values ​​arranged in ascending order, and the target charging parameters include the target charging cut-off voltage and the target charging rate; Based on the target temperature range, the target charging mode corresponding to the target battery is determined, wherein the target charging mode is at least one of constant current charging mode, constant voltage charging mode and pulse charging mode; In the target charging mode, the target battery is controlled to charge according to the target charging parameters; Wherein, the first mapping relationship characterizes the relationship between temperature range and charging cutoff voltage, and the second mapping relationship characterizes the relationship between temperature range and charging rate. The second mapping relationship includes a first rate-temperature relationship corresponding to the extremely low temperature range, a second rate-temperature relationship corresponding to the sub-low temperature range, a third rate-temperature relationship corresponding to the transition temperature range, and a fourth rate-temperature relationship corresponding to the normal temperature range. The first rate-temperature relationship is: the charging rate is a first preset rate. The second rate-temperature relationship is: the charging rate and the operating temperature exhibit a third linear relationship with a third slope value and a third intercept, wherein the third slope... The value and the third intercept are both determined based on the temperature range value of the sub-low temperature zone, the first preset multiplier, and the second preset multiplier, wherein the second preset multiplier is greater than the first preset multiplier; the third multiplier temperature relationship is as follows: the charging multiplier and the operating temperature exhibit a fourth linear relationship with a fourth slope value and a fourth intercept, wherein the fourth slope value and the fourth intercept are both determined based on the temperature range value of the transition temperature zone, the second preset multiplier, and the third preset multiplier, wherein the third preset multiplier is greater than the second preset multiplier; the fourth multiplier temperature relationship is as follows: the charging multiplier is any multiplier between the third preset multiplier and the maximum multiplier.

2. The method according to claim 1, characterized in that, The first mapping relationship includes a first voltage-temperature relationship corresponding to the extremely low temperature region, a second voltage-temperature relationship corresponding to the sub-low temperature region, a third voltage-temperature relationship corresponding to the transition temperature region, and a fourth voltage-temperature relationship corresponding to the normal temperature region. The first voltage-temperature relationship is as follows: the charging cutoff voltage is a first preset voltage; The second voltage-temperature relationship is as follows: the charging cut-off voltage and the operating temperature exhibit a first linear relationship with a first slope value and a first intercept. The first slope value and the first intercept are both determined based on the temperature range value of the sub-low temperature region, the first preset voltage, and the second preset voltage. The second preset voltage is greater than the first preset voltage. The third voltage-temperature relationship is as follows: the charging cut-off voltage and the operating temperature exhibit a second linear relationship with a second slope value and a second intercept. The second slope value and the second intercept are both determined based on the temperature range value of the transition temperature zone, the second preset voltage, and the third preset voltage. The third preset voltage is greater than the second preset voltage. The fourth voltage-temperature relationship is as follows: the charging cut-off voltage is the third preset voltage.

3. The method according to claim 2, characterized in that, The voltage parameter is set to any one of the first preset voltage, the second preset voltage, and the third preset voltage. Determining the voltage parameter includes: The temperature sampling range used to determine the first preset voltage is set as the extremely low temperature region; The temperature sampling range used to determine the second preset voltage is set as the sub-low temperature region and the transition temperature region; The temperature sampling range used to determine the third preset voltage is set to the normal temperature range; Multiple sample batteries are charged at any temperature within the temperature sampling range and at different charging rates. The battery voltage of the sample battery is recorded at each charging rate when the negative electrode potential first drops to zero, and a voltage set is obtained. The median of the voltage set is calculated, and the median is determined as the voltage parameter.

4. The method according to claim 1, characterized in that, The magnification parameter is set to any one of the first preset magnification, the second preset magnification, and the third preset magnification. Determining the magnification parameter includes: The temperature sampling range used to determine the first preset magnification is set as the extremely low temperature region; The temperature sampling range used to determine the second preset magnification is set as the sub-low temperature region and the transition temperature region; The temperature sampling range used to determine the third preset magnification is set as the normal temperature zone; Multiple sample batteries are charged at any temperature within the temperature sampling range and at different charging rates. The critical rate of the sample battery when the negative electrode potential first drops to zero is recorded at each charging rate to obtain a set of charging rates. The median of the set of multiples is calculated, and the median is determined as the multiple parameter.

5. The method according to claim 1, characterized in that, The step of determining the target charging mode corresponding to the target battery based on the target temperature range includes: If the target temperature range belongs to the extremely low temperature region, the target charging mode is determined to be the first charging mode, and the first charging mode is the constant current charging mode. If the target temperature range falls within the sub-low temperature range, the target charging mode is determined to be the second charging mode. The second charging mode is a charging mode that combines pulse charging mode and constant voltage charging mode. The pulse charging mode is to charge the battery with a pulse signal. If the target temperature range falls within the transition temperature range or the normal temperature range, the target charging mode is determined to be the third charging mode, which is a charging mode combining constant current charging mode and constant voltage charging mode.

6. The method according to claim 5, characterized in that, The target charging mode is a first charging mode, and the step of controlling the target battery to charge according to the target charging parameters includes: The target battery is controlled to be charged at the target charging rate and in the constant current charging mode, and the charging of the target battery is stopped when it reaches the target charging cutoff voltage.

7. The method according to claim 5, characterized in that, When the target charging mode is the second charging mode, controlling the target battery to charge according to the target charging parameters includes: The average current of the pulse signal is determined based on the target charging rate and the rated capacity of the target battery. The peak current is determined based on the average current and the target duty cycle of the pulse signal; The target battery is charged and its voltage is monitored using a pulse signal with the amplitude of the peak current and the target duty cycle. When the battery voltage reaches the target charging cutoff voltage, the target battery is controlled to enter the constant voltage charging mode at the target charging cutoff voltage.

8. The method according to claim 7, characterized in that, The monitoring of the battery voltage of the target battery includes: Real-time monitoring of voltage valley values ​​within the pulse cycle; When the voltage valley reaches the warning voltage, it is determined that the next positive pulse will touch the charging cutoff voltage.

9. The method according to claim 7, characterized in that, The process of determining the target duty cycle includes: Select an operating temperature belonging to the sub-low temperature region, and determine the target charging rate and target charging cut-off voltage at the operating temperature; The sample battery is charged using multiple preset duty cycle values ​​and the target charging rate until the battery voltage reaches the target charging cutoff voltage, and the charging amount after each charge is recorded. Determine the maximum value among all charging capacities, and use the preset duty cycle value corresponding to the maximum value as the target duty cycle; Each of the preset duty cycle values ​​is determined by a preset on-time and a fixed rest time. The preset on-time is the total duration of the pulse signal in the high-level on state within one cycle, and the fixed rest time is the total duration of the pulse signal in the low-level off state within one cycle.

10. The method according to claim 5, characterized in that, The target charging mode is the third charging mode, and the step of controlling the target battery to charge according to the target charging parameters includes: The constant current charging value in the constant current charging mode is determined based on the product of the target charging rate and the rated capacity of the target battery. The target battery is controlled to enter the constant current charging mode where the charging current is the constant current charging value, and when the target battery is charged to the target charging cutoff voltage, the target battery is controlled to enter the constant voltage charging mode.

11. A sodium-ion battery charging control device, characterized in that, The device includes: The range determination module is used to obtain the operating temperature of the target battery and determine the target temperature range to which the operating temperature belongs; The parameter determination module is used to determine the target charging parameters corresponding to the target temperature range according to the first mapping relationship and the second mapping relationship; wherein, the temperature range includes an extremely low temperature range, a sub-low temperature range, a transition temperature range and a normal temperature range with the temperature values ​​arranged in ascending order, and the target charging parameters include the target charging cut-off voltage and the target charging rate; The mode determination module is used to determine the target charging mode corresponding to the target battery based on the target temperature range, wherein the target charging mode is at least one of constant current charging mode, constant voltage charging mode and pulse charging mode; A charging control module is used to control the target battery to charge according to the target charging parameters in the target charging mode. Wherein, the first mapping relationship characterizes the relationship between temperature range and charging cutoff voltage, and the second mapping relationship characterizes the relationship between temperature range and charging rate. The second mapping relationship includes a first rate-temperature relationship corresponding to the extremely low temperature range, a second rate-temperature relationship corresponding to the sub-low temperature range, a third rate-temperature relationship corresponding to the transition temperature range, and a fourth rate-temperature relationship corresponding to the normal temperature range. The first rate-temperature relationship is: the charging rate is a first preset rate. The second rate-temperature relationship is: the charging rate and the operating temperature exhibit a third linear relationship with a third slope value and a third intercept, wherein the third slope... The value and the third intercept are both determined based on the temperature range value of the sub-low temperature zone, the first preset multiplier, and the second preset multiplier, wherein the second preset multiplier is greater than the first preset multiplier; the third multiplier temperature relationship is as follows: the charging multiplier and the operating temperature exhibit a fourth linear relationship with a fourth slope value and a fourth intercept, wherein the fourth slope value and the fourth intercept are both determined based on the temperature range value of the transition temperature zone, the second preset multiplier, and the third preset multiplier, wherein the third preset multiplier is greater than the second preset multiplier; the fourth multiplier temperature relationship is as follows: the charging multiplier is any multiplier between the third preset multiplier and the maximum multiplier.

12. An electronic device comprising a memory and a processor, wherein the memory stores a computer program, characterized in that, When the processor executes the computer program, it implements the steps of the method according to any one of claims 1 to 10.

13. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by a processor, it implements the steps of the method according to any one of claims 1 to 10.

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