Method for exploring low-temperature charging strategy of sodium-ion battery and application thereof

Abstract

The present application relates to the technical field of sodium ion batteries, in particular to a method for exploring a low-temperature charging strategy of a sodium ion battery and application thereof. The method comprises: obtaining a low-temperature capacity retention rate CR, a room-temperature capacity recovery rate CRR and a negative electrode sodium precipitation condition of the sodium ion battery; when CR is greater than or equal to 99%, CRR is greater than or equal to 99% and the negative electrode does not precipitate sodium, gradually increasing the preset cut-off voltage, repeating the operation until at least one of CR being greater than or equal to 99%, CRR being greater than or equal to 99% and the negative electrode not precipitating sodium is not met; when at least one of CR being greater than or equal to 99%, CRR being greater than or equal to 99% and the negative electrode not precipitating sodium is not met, gradually decreasing the preset cut-off voltage, repeating the operation until CR is greater than or equal to 99%, CRR is greater than or equal to 99% and the negative electrode does not precipitate sodium are simultaneously met. The method can explore a suitable charging rate and a charging upper limit voltage of the sodium ion battery at low temperature, thereby providing a safe, fast and reliable charging strategy of the sodium ion battery at low temperature.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of sodium ion batteries, in particular to a method for exploring a low-temperature charging strategy of a sodium ion battery and application thereof. BACKGROUND

[0002] Sodium ion batteries are one of the most promising secondary batteries after lithium ion batteries, and have low raw material cost, excellent rate performance and low-temperature performance. Unlike lithium ion batteries, sodium ion batteries can also be charged to a certain extent in a low-temperature environment. As one of the advantages of sodium ion batteries, low-temperature charging and discharging enables sodium ion batteries to be applied in low-speed electric vehicles, electric vehicles and energy storage systems without complex thermal management systems, thereby reducing costs.

[0003] However, in a low-temperature environment, if there is no suitable charging rate and upper limit of charging voltage, sodium may be precipitated from the sodium ion battery, thereby reducing the cycle life of the sodium ion battery.

[0004] Therefore, the present application is proposed. SUMMARY

[0005] A first object of the present application is to provide a method for exploring a low-temperature charging strategy of a sodium ion battery, which can explore a suitable charging rate and upper limit of charging voltage of the sodium ion battery in a low-temperature environment, thereby providing a safe, fast and reliable charging strategy for the sodium ion battery in a low-temperature environment.

[0006] A second object of the present application is to provide application of the method for exploring a low-temperature charging strategy of a sodium ion battery in a sodium ion battery and an electric device containing the sodium ion battery.

[0007] In order to achieve the above objects of the present application, the following technical solutions are adopted:

[0008] The present application provides a method for exploring a low-temperature charging strategy of a sodium ion battery, comprising the following steps:

[0009] S1: obtaining a low-temperature capacity retention rate CR and a room-temperature capacity recovery rate CRR of the sodium ion battery:

[0010] at room temperature, discharging the sodium ion battery at 0.5C to its discharge cut-off voltage, then charging it at 0.5C / 0.05C constant current and constant voltage to its charge cut-off voltage, discharging it at 0.5C to its discharge cut-off voltage, and repeating the constant current and constant voltage charging-discharging x times to obtain an average discharge capacity C0;

[0011] After the sodium ion battery is placed at a preset temperature for a first preset time, the sodium ion battery is first charged at a preset rate to a preset cut-off voltage, then discharged at a 0.5C discharge current to a discharge cut-off voltage, and cycled for n times, to obtain a low-temperature charge capacity and a low-temperature discharge capacity each time, wherein the first low-temperature discharge capacity is LT-C1, and the n-th low-temperature discharge capacity is LT-C n ;

[0012] After the sodium ion battery is placed at room temperature for a second preset time, the sodium ion battery is first charged at a 0.5C / 0.05C constant current and constant voltage to a charge cut-off voltage, then discharged at a 0.5C to a discharge cut-off voltage, and cycled for y times, to obtain a room-temperature charge capacity and a room-temperature discharge capacity each time, wherein the first room-temperature discharge capacity is AMB-C1.

[0013] After the sodium ion battery is charged at a 0.5C to a charge cut-off voltage at room temperature, the sodium ion battery is disassembled, and the negative electrode is observed for sodium precipitation.

[0014] CR and CRR are calculated, CR = LT-C n / LT-C1x 100%, and CRR = AMB-C1 / C0x 100%;

[0015] S2: When CR is greater than or equal to 99%, CRR is greater than or equal to 99%, and the negative electrode does not precipitate sodium, gradually increase the preset cut-off voltage, and repeat step S1 until at least one of CR is greater than or equal to 99%, CRR is greater than or equal to 99%, and the negative electrode does not precipitate sodium is not met; when at least one of CR is greater than or equal to 99%, CRR is greater than or equal to 99%, and the negative electrode does not precipitate sodium is not met, gradually decrease the preset cut-off voltage, and repeat step S1 until CR is greater than or equal to 99%, CRR is greater than or equal to 99%, and the negative electrode does not precipitate sodium are all met.

[0016] In step S1, the preset temperature is less than the room temperature.

[0017] Further, the room temperature is 25℃; and / or, the preset temperature is less than 25℃.

[0018] Further, the gradient interval for gradually increasing the preset cut-off voltage or gradually decreasing the preset cut-off voltage is 0.1V.

[0019] Further, in step S2, when CR≥99%, CRR≥99% and the negative electrode does not deposit sodium, gradually increase the preset cut-off voltage, and repeat step S1 until at least one of CR≥99%, CRR≥99% and the negative electrode does not deposit sodium is not met, determine the highest preset cut-off voltage that meets CR≥99%, CRR≥99% and the negative electrode does not deposit sodium as the highest safe charging voltage under the corresponding preset temperature and the corresponding preset rate; when at least one of CR≥99%, CRR≥99% and the negative electrode does not deposit sodium is not met, gradually decrease the preset cut-off voltage, and repeat step S1 until CR≥99%, CRR≥99% and the negative electrode does not deposit sodium are simultaneously met, determine the preset cut-off voltage that meets CR≥99%, CRR≥99% and the negative electrode does not deposit sodium as the highest safe charging voltage under the corresponding preset temperature and the corresponding preset rate.

[0020] Further, adjust the preset rate, and repeat step S1 and step S2 to obtain the highest safe charging voltage under different preset rates.

[0021] Further, the gradient interval of the preset rate is adjusted to 0.1C.

[0022] Further, adjust the preset temperature, and repeat step S1 and step S2 to obtain the highest safe charging voltage under different preset temperatures.

[0023] Further, the gradient interval of the preset temperature is adjusted to 10℃.

[0024] Further, in step S1, the x≥3.

[0025] Further, in step S1, the first preset time≥5h.

[0026] Further, in step S1, the preset rate is 0.1C-5C.

[0027] Further, in step S1, the preset cut-off voltage is the discharge cut-off voltage of the sodium ion battery-the charge cut-off voltage of the sodium ion battery.

[0028] Further, in step S1, the n≥10.

[0029] Further, in step S1, the second preset time≥3h.

[0030] Further, in step S1, the y≥10.

[0031] The application further provides an application of the exploration method of the low-temperature charging strategy of the sodium ion battery in a sodium ion battery and a power consumption equipment containing the sodium ion battery.

[0032] Compared with the prior art, the application has the following beneficial effects:

[0033] (1) The method for exploring the low-temperature charging strategy of the sodium ion battery provided by the application can explore the appropriate charging rate and charging upper limit voltage of the sodium ion battery at low temperature, thereby providing a safe, fast and reliable charging strategy for the sodium ion battery at low temperature.

[0034] (2) The method for exploring the low-temperature charging strategy of the sodium ion battery provided by the application can accurately analyze the low-temperature charging performance of the sodium ion battery by comprehensively determining the low-temperature capacity retention rate CR, the room-temperature capacity recovery rate CRR and the sodium precipitation of the sodium ion battery.

[0035] (3) The method for exploring the low-temperature charging strategy of the sodium ion battery provided by the application can quickly analyze the highest charging voltage at different rates at different temperatures through low-temperature cycling, then room-temperature cycling and disassembly. BRIEF DESCRIPTION OF DRAWINGS

[0036] In order to more clearly illustrate the technical solutions in the specific embodiments or the prior art, the drawings needed in the description of the specific embodiments or the prior art will be briefly introduced. Obviously, the drawings in the following description are some embodiments of the application, and for those skilled in the art, other drawings can be obtained without creative labor on the basis of these drawings.

[0037] Figure 1 The flowchart of the method for exploring the low-temperature charging strategy of the sodium ion battery provided by the application is shown in the figure. DETAILED DESCRIPTION

[0038] The technical solutions of the application will be described clearly and completely in the following with reference to the drawings and specific embodiments, but those skilled in the art will understand that the following described embodiments are part of the embodiments of the application, not all the embodiments, and are only used to illustrate the application, and should not be regarded as limiting the scope of the application. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the application. The specific conditions not mentioned in the embodiments are carried out according to the conventional conditions or the conditions recommended by the manufacturer. The reagents or instruments not mentioned by the manufacturer are all conventional products that can be purchased on the market.

[0039] If there is no special indication, in the present application, "first aspect", "second aspect", "third aspect" and the like are only for the purpose of description, and cannot be understood as indicating or implying relative importance or quantity, nor can it be understood as implying the importance or quantity of the indicated technical features. Moreover, "first", "second", "third" and the like only serve the purpose of non-exhaustive enumeration description, and should be understood as not constituting a closed limitation on the quantity.

[0040] If there is no special indication, the "includes" and "contains" mentioned in the present application mean open type, and can also be closed type. For example, the "includes" and "contains" can mean that other components not listed can also be included or contained, or only the listed components can be included or contained.

[0041] If there is no special indication, in the present application, "one or more" or "at least one" means any one, any two or any two or more of the listed items. Among them, "several" means any two or more.

[0042] In a first aspect, the present application provides a method for exploring the low-temperature charging strategy of a sodium-ion battery, as shown in Figure 1 The flowchart of the method for exploring the low-temperature charging strategy of a sodium-ion battery is shown in the figure, which specifically includes the following steps:

[0043] Step S1: Obtain the low-temperature capacity retention rate CR and room temperature capacity recovery rate CRR values of the sodium-ion battery, and the obtaining method is as follows:

[0044] At room temperature, the sodium-ion battery is discharged to its discharge cut-off voltage at 0.5C, then charged to its charge cut-off voltage at 0.5C / 0.05C constant current and constant voltage, and discharged to its discharge cut-off voltage at 0.5C, and the above constant current and constant voltage charging-discharging is cycled x times to obtain the average discharge capacity C0 of x times. Wherein, the 0.5C / 0.05C constant current and constant voltage charging means charging to the cut-off voltage at 0.5C constant current, and then charging to the cut-off voltage at constant voltage until the current is less than 0.05C. It can be understood that after cycling x times, a plurality of discharge capacities are obtained, and the average value of the plurality of discharge capacities is the average discharge capacity C0.

[0045] Further, the sodium-ion battery is placed at a preset temperature for a first preset time, so that the difference between the battery temperature and the preset temperature is within an error range, wherein the error range is ±2℃. Then, the sodium-ion battery is first charged to a preset cut-off voltage at a preset rate constant current, and then discharged to its discharge cut-off voltage at 0.5C discharge current, and the charging and discharging process is cycled n times to obtain the low-temperature charging capacity and the low-temperature discharging capacity each time, wherein the low-temperature discharging capacity of the first time is LT-C1, and the low-temperature discharging capacity of the n-th time is LT-Cn. n . Wherein, the first preset time can be dynamically adjusted according to the temperature difference between the environment and the battery.

[0046] Further, the sodium ion battery is left at room temperature for a second preset time, so that the difference between the battery temperature and the room temperature is within an error range, wherein the error range is ±2℃. Then, the sodium ion battery is first charged at 0.5C / 0.05C constant current and constant voltage to the charge cut-off voltage, and then discharged at 0.5C to the discharge cut-off voltage, and the charging and discharging process is cycled y times, to obtain the room temperature charging capacity and the room temperature discharging capacity each time, wherein the room temperature discharging capacity of the first time is AMB-C1. Wherein, the second preset time can be dynamically adjusted according to the temperature difference between the ambient temperature and the battery. Wherein, the 0.5C / 0.05C constant current and constant voltage charging refers to charging at 0.5C constant current to the cut-off voltage, and then charging at constant voltage until the current is less than 0.05C.

[0047] It can be understood that, between each charging and each discharging, a rest, or in other words, a standing, is performed. Wherein, the rest time can be 30min.

[0048] Further, after the sodium ion battery is charged at 0.5C to the charge cut-off voltage at room temperature, the sodium ion battery is disassembled, the sodium precipitation of the negative electrode is observed, and whether the sodium precipitation occurs is determined.

[0049] CR and CRR are calculated, wherein the calculation method is as follows: CR=LT-C n / LT-C1×100%,CRR=AMB-C1 / C0×100%.

[0050] Step S2: judgment: when CR≥99%, CRR≥99% and the negative electrode does not precipitate sodium are simultaneously satisfied, gradually increase the preset cut-off voltage, and repeat step S1 until at least one of CR≥99%, CRR≥99% and the negative electrode does not precipitate sodium is not satisfied; when at least one of CR≥99%, CRR≥99% and the negative electrode does not precipitate sodium is not satisfied, gradually decrease the preset cut-off voltage, and repeat step S1 until CR≥99%, CRR≥99% and the negative electrode does not precipitate sodium are simultaneously satisfied.

[0051] In step S1, the preset temperature is < the room temperature.

[0052] The sodium ion battery low-temperature charging strategy exploration method provided by the application can explore the appropriate charging rate and charging upper limit voltage of the sodium ion battery at low temperature, thereby providing a safe, fast and reliable charging strategy for the sodium ion battery at low temperature.

[0053] The application can accurately analyze the low-temperature charging performance of the sodium ion battery by comprehensively determining the low-temperature capacity retention rate CR, the room temperature capacity recovery rate CRR and the sodium precipitation of the sodium ion battery.

[0054] And, the present application can quickly analyze the highest charging voltage of different rates at different temperatures by low-temperature circulation and then room-temperature circulation and disassembly.

[0055] In some specific embodiments, the room temperature is 25℃.

[0056] In some specific embodiments, the preset temperature is less than 25℃ and greater than or equal to -40℃. This temperature range can cover the minimum temperature of most regions.

[0057] In some specific embodiments, the preset temperature is less than 25℃ and greater than or equal to -40℃. This temperature range can cover the minimum temperature of most regions.

[0058] In some specific embodiments, the gradient interval of gradually increasing or gradually decreasing the preset cutoff voltage is 0.1V.

[0059] In some specific embodiments, in step S2, when CR≥99%, CRR≥99% and the negative electrode does not precipitate sodium, the preset cutoff voltage is gradually increased, and step S1 is repeated until at least one of CR≥99%, CRR≥99% and the negative electrode does not precipitate sodium is not met, and the highest preset cutoff voltage that meets CR≥99%, CRR≥99% and the negative electrode does not precipitate sodium is determined as the highest safe charging voltage under the corresponding preset temperature and the corresponding preset rate.

[0060] Further, when at least one of CR≥99%, CRR≥99% and the negative electrode does not precipitate sodium is not met, the preset cutoff voltage is gradually decreased, and step S1 is repeated until CR≥99%, CRR≥99% and the negative electrode does not precipitate sodium are all met, and the preset cutoff voltage that meets CR≥99%, CRR≥99% and the negative electrode does not precipitate sodium is determined as the highest safe charging voltage under the corresponding preset temperature and the corresponding preset rate.

[0061] In some specific embodiments, the preset rate is adjusted, and steps S1 and S2 are repeated to obtain the highest safe charging voltage under different preset rates.

[0062] In some specific embodiments, the gradient interval of adjusting the preset rate is 0.1C.

[0063] In some specific embodiments, the preset temperature is adjusted, and steps S1 and S2 are repeated to obtain the highest safe charging voltage under different preset temperatures.

[0064] In some specific embodiments, the gradient interval of the preset temperature is 10℃.

[0065] The application provides a test method for exploring the safe charging boundary of a sodium ion battery in a low-temperature environment. Through charging tests at different temperatures, different rates, and different upper limit voltages, the best charging strategy of the sodium ion battery at low temperature is found out, which is fast, safe, and reliable.

[0066] According to the highest voltage meeting the above-mentioned determination standard at each temperature and each rate, a required charging strategy can be formulated.

[0067] In some specific embodiments, in step S1, x≥3, including but not limited to any one of the point values of 3, 4, 5, 6, 7, 8, 10 or a range value between any two of them.

[0068] In some specific embodiments, in step S1, the first preset time is≥5h; including but not limited to any one of the point values of 5h, 6h, 7h, 8h or a range value between any two of them. Only when the battery is rested for enough time at the corresponding temperature, the temperature from the outside to the inside is consistent with the ambient temperature.

[0069] In some specific embodiments, in step S1, the preset rate is 0.1C-5C; including but not limited to any one of the point values of 0.1C, 0.3C, 0.5C, 0.8C, 1C, 1.3C, 1.5C, 2C, 2.5C, 3C, 3.5C, 4C, 4.5C, 5C or a range value between any two of them.

[0070] In some specific embodiments, in step S1, the preset cutoff voltage is the discharge cutoff voltage of the sodium ion battery-the charging cutoff voltage of the sodium ion battery.

[0071] The range of the preset rate and the preset cutoff voltage is the normal use range at room temperature, which is to explore a charging strategy with more charging capacity and faster charging speed at low temperature without sacrificing the battery life and performance.

[0072] In some specific embodiments, in step S1, n≥10, including but not limited to any one of the point values of 10, 11, 12, 13, 14, 15, 16, 18, 20, 23, 25, 28, 30, 33, 35, 38, 40, 42, 45, 48, 50 or a range value between any two of them. Preferably, n=10-50.

[0073] In some specific embodiments, in step S1, the second preset time is≥3h; including but not limited to any one of the point values of 3h, 4h, 5h, 6h, 7h, 8h or a range value between any two of them.

[0074] In some specific embodiments, in step S1, y≥10, including but not limited to any one of 10, 11, 12, 13, 15, 18, 20, 25, 30, 35, 40, 45, 50 or a range value between any two of them. Preferably, y = 10-50.

[0075] In a second aspect, the application provides an application of the method for exploring the optimal charging strategy of the sodium-ion battery at low temperature to the sodium-ion battery and the electric device containing the sodium-ion battery.

[0076] Embodiments of the application will be described in detail below with reference to examples, but those skilled in the art will understand that the following examples are only for illustration of the application and should not be regarded as limiting the scope of the application. If the specific conditions are not specified in the examples, the conventional conditions or the conditions recommended by the manufacturer are used. If the reagents or instruments used are not specified by the manufacturer, they are all conventional products that can be obtained by purchase.

[0077] Example 1

[0078] Taking 32140-MP10 sodium-ion battery as an example, the method for exploring the optimal charging strategy of the sodium-ion battery at low temperature provided in this embodiment includes the following steps:

[0079] (1) At room temperature (25℃), a) the battery is discharged at 0.5C constant current to 2V, and stands for 30min, b) then charged to 4V at 0.5C / 0.05C constant current and constant voltage, and stands for 30min, c) discharged to 2V at 0.5C constant current, and stands for 30min, steps b)-c) are cycled three times, to obtain the average discharge capacity C0;

[0080] (2) The battery is placed at a preset temperature -10℃ for a first preset time 5h, so that the difference between the temperature of the battery and the preset temperature -10℃ is within an error range ±2℃;

[0081] (3) The battery is charged to a preset cut-off voltage 3.6V at a preset rate 0.1C constant current, and stands for 30min, then discharged to the cut-off voltage 2V at a standard discharge current 0.5C, and stands for 30min;

[0082] (4) Step (3) is cycled for a fixed number of times 10 times, to obtain the charge capacity LT-CHG-C1, LT-CHG-C2, LT-CHG-C3, …, LT-CHG-C 10 , and the discharge capacity LT-C1, LT-DIS-C2, LT-DIS-C3, …, LT-DIS-C 10 of the battery at low temperature; wherein the first low-temperature discharge capacity is LT-C1, the nth low-temperature discharge capacity is LT-C n ;

[0083] (5) The battery is restored to room temperature, and is left to stand at room temperature for a second preset time 3h, so that the difference between the temperature of the battery and the room temperature is within an error range;

[0084] (6) 0.5C / 0.05C constant current and constant voltage charging is performed to 4V, left to stand for 30min, 0.5C constant current discharging is performed to 2V, left to stand for 30min, and the cycle is repeated for 10 times, to obtain the charging capacity AMB-CHG-C1, AMB-CHG-C2, AMB-CHG-C3, …, AMB-CHG-C 10 , and the discharging capacity AMB-C1, AMB-C2, AMB-C3, …, AMB-C 10 ; wherein the first room temperature discharging capacity is AMB-C1;

[0085] (7) The above battery is subjected to standard charging (charging to the product specified charging cut-off voltage at 0.5C) at room temperature, and the fully charged battery is disassembled, and no sodium precipitation is observed in the negative electrode;

[0086] (8) The low-temperature capacity retention rate CR and the room temperature capacity recovery rate CRR of the battery are calculated, wherein CR = LT-C n / LT-C1x 100%, and CRR = AMB-C1 / C0x 100%, and the results are shown in Table 1, which satisfy CR≥99%, CRR≥99% and no sodium precipitation in the negative electrode (to improve accuracy, two groups of batteries are tested in this scheme, and Table 1 shows the test results of the two groups of batteries).

[0087] The preset cut-off voltage is raised to 3.7V, and the above test is repeated, and the obtained CR, CRR and negative electrode sodium precipitation are shown in Table 1 (to improve accuracy, two groups of batteries are tested in this scheme, and Table 1 shows the test results of the two groups of batteries).

[0088] Table 1 CR, CRR and negative electrode sodium precipitation

[0089]

[0090]

[0091] It can be found from Table 1 that the highest safe charging voltage of this type of battery at-10℃ and 0.1C is 3.6V.

[0092] The preset rate is changed in sequence, and the above test method is repeated, to finally obtain a suitable charging strategy at this temperature.

[0093] The preset temperature is changed in sequence, and the above test is repeated, to finally obtain a full-temperature charging strategy for the sodium ion battery.

[0094] Although the present application has been described and illustrated with a certain degree of particularity, it is understood that the present application has been made by way of examples only and that numerous changes in the details of execution can be made by those skilled in the art without departing from the spirit and scope of the application. It is therefore intended to cover in the appended claims all such changes and modifications that come within the scope of the application.

Claims

1. A method for exploring low-temperature charging strategies for sodium-ion batteries, characterized in that, Comprising the following steps: S1: obtaining the low-temperature capacity retention rate CR and the room-temperature capacity recovery rate CRR of the sodium-ion battery: at room temperature, discharging the sodium-ion battery to its discharge cut-off voltage at 0.5C, then charging it to its charge cut-off voltage at 0.5C / 0.05C constant current-constant voltage, discharging it to its discharge cut-off voltage at 0.5C, and repeating the constant current-constant voltage charging-discharging x times to obtain an average discharge capacity C0; After the sodium ion battery is placed at a preset temperature for a first preset time, the sodium ion battery is first charged at a preset rate to a preset cut-off voltage, then discharged at a 0.5C discharge current to a discharge cut-off voltage, and cycled for n times to obtain a low-temperature charge capacity and a low-temperature discharge capacity each time, wherein the first low-temperature discharge capacity is LT-C1, and the n th low-temperature discharge capacity is LT-Cn. n ; after the sodium-ion battery is left to stand at room temperature for a second preset time, first charging the sodium-ion battery to its charge cut-off voltage at 0.5C / 0.05C constant current-constant voltage, then discharging it to its discharge cut-off voltage at 0.5C, and repeating the charging and discharging y times to obtain the room-temperature charging capacity and the room-temperature discharging capacity each time, wherein the first room-temperature discharging capacity is AMB-C1; at room temperature, charging the sodium-ion battery to the charge cut-off voltage at 0.5C, then disassembling the sodium-ion battery, and observing the sodium precipitation of the negative electrode; Compute CR and CRR, CR = LT - C n / LT - C1 x 100%, CRR = AMB - C1 / C0 x 100%; S2: when CR≥99%, CRR≥99%, and the negative electrode does not precipitate sodium, gradually increasing the preset cut-off voltage, and repeating step S1 until at least one of CR≥99%, CRR≥99%, and the negative electrode not precipitating sodium is not met; when at least one of CR≥99%, CRR≥99%, and the negative electrode not precipitating sodium is not met, gradually decreasing the preset cut-off voltage, and repeating step S1 until CR≥99%, CRR≥99%, and the negative electrode not precipitating sodium are all met. In step S1, the preset temperature < the room temperature.

2. The method of claim 1, wherein the sodium-ion battery low-temperature charging strategy is explored. The room temperature is 25℃; and / or, the preset temperature < 25℃.

3. The method of claim 1, wherein the sodium-ion battery low-temperature charging strategy is explored. The gradient interval of gradually increasing the preset cut-off voltage or gradually decreasing the preset cut-off voltage is 0.1V.

4. The method of claim 1, wherein the sodium-ion battery low-temperature charging strategy is explored. In step S2, when CR≥99%, CRR≥99%, and the negative electrode does not precipitate sodium, gradually increasing the preset cut-off voltage, and repeating step S1 until at least one of CR≥99%, CRR≥99%, and the negative electrode not precipitating sodium is not met, determining that the highest preset cut-off voltage meeting CR≥99%, CRR≥99%, and the negative electrode not precipitating sodium is the highest safe charging voltage under the corresponding preset temperature and the corresponding preset rate; when at least one of CR≥99%, CRR≥99%, and the negative electrode not precipitating sodium is not met, gradually decreasing the preset cut-off voltage, and repeating step S1 until CR≥99%, CRR≥99%, and the negative electrode not precipitating sodium are all met, determining that the preset cut-off voltage meeting CR≥99%, CRR≥99%, and the negative electrode not precipitating sodium is the highest safe charging voltage under the corresponding preset temperature and the corresponding preset rate.

5. The method of claim 4, wherein the sodium-ion battery low-temperature charging strategy is explored, characterized by, adjusting the preset rate, and repeating step S1 and step S2 to obtain the highest safe charging voltage under different preset rates; adjusting the gradient interval of the preset rate to 0.1C.

6. The method of claim 4, wherein the sodium-ion battery low-temperature charging strategy is explored, characterized by, adjusting the preset temperature, and repeating step S1 and step S2 to obtain the highest safe charging voltage under different preset temperatures; adjusting the gradient interval of the preset temperature to 10℃.

7. The method of claim 1, wherein the sodium-ion battery low-temperature charging strategy is explored. In step S1, x≥3.

8. The method of claim 1, wherein the sodium-ion battery low-temperature charging strategy is explored, and In step S1, at least one of the following conditions is met: (1) the first preset time ≥ 5h; (2) the preset rate is 0.1C~5C; (3) the preset cut-off voltage is the discharge cut-off voltage of the sodium ion battery~the charge cut-off voltage of the sodium ion battery; (4) the n≥10.

9. The method of claim 1, wherein the sodium-ion battery low-temperature charging strategy is explored, characterized by, In step S1, at least one of the following conditions is met: (1) the second preset time≥3h; (2) the y≥10.

10. The application of the method for exploring the low-temperature charging strategy of the sodium ion battery according to any one of claims 1~9 in the sodium ion battery and the power consumption equipment containing the sodium ion battery.

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