Battery heating strategy determination method and device and storage medium

Abstract

The embodiment of the invention provides a battery heating strategy determination method and device and a storage medium, and the method comprises the steps: extracting the target ohmic impedance corresponding to each target temperature parameter through testing the electrochemical impedance spectrum of a battery under a plurality of target temperature parameters, calculating the ohmic impedance coefficient reflecting the sensitivity of the ohmic impedance of the battery to the temperature, and determining the heating strategy of the battery according to the ohmic impedance coefficient. Therefore, a differentiated heating strategy is matched according to the value of the ohmic impedance coefficient. According to the method, accurate adaptation between the heating strategy and the inherent impedance-temperature characteristic of the battery is achieved, the pulse self-heating efficiency is effectively improved, the heating time is remarkably shortened, and meanwhile the situation that the heating efficiency is low due to the fact that the battery types are different in a fixed heating strategy in the related technology is avoided.

Description

Technical Field

[0001] This invention relates to the field of battery technology, and more specifically to a method, apparatus and storage medium for determining a battery heating strategy. Background Technology

[0002] In low-temperature environments, lithium-ion batteries face risks such as a sharp drop in electrolyte conductivity, sluggish reaction kinetics, and hindered solid-phase diffusion, which can easily lead to a surge in internal resistance and a sharp reduction in usable capacity. This results in a significant reduction in the driving range of electric vehicles, a decrease in charging rate, and limited power output, and can even induce lithium plating on the negative electrode during low-temperature charging. Therefore, preheating the battery before driving or charging can suppress lithium plating, increase usable capacity, and restore power output. External heating solutions in related technologies have low energy utilization and uneven temperature distribution. Pulse self-heating utilizes the battery's internal resistance to generate heat, resulting in a fast temperature rise rate and high temperature uniformity, without the need for an external heat source, directly improving low-temperature charge and discharge performance and safety. However, pulse heating in related technologies uses a fixed current / frequency, which cannot be adapted to battery types with significantly different ohmic impedance temperature characteristics, and the single strategy leads to low heating efficiency. Summary of the Invention

[0003] The embodiments of the present invention provide a method, device and storage medium for determining a battery heating strategy, which can improve the technical problem that using a fixed current / frequency cannot adapt to battery types with significant differences in ohmic impedance temperature characteristics, and that a single strategy leads to low heating efficiency.

[0004] In a first aspect, embodiments of the present invention provide a method for determining a battery heating strategy, comprising:

[0005] The battery was tested at multiple target temperature parameters to obtain its electrochemical impedance spectroscopy.

[0006] The target ohmic impedance of the battery at each target temperature parameter is determined based on the electrochemical impedance spectroscopy.

[0007] The ohmic impedance coefficient of the battery at each of the target temperature parameters is determined based on the target ohmic impedance.

[0008] The heating strategy for the battery is determined based on the ohmic impedance coefficient.

[0009] In one embodiment, determining the target ohmic impedance of the battery at each target temperature parameter based on the electrochemical impedance spectroscopy includes:

[0010] The target frequency corresponding to each target temperature parameter is determined based on the electrochemical impedance spectroscopy.

[0011] The target ohmic impedance of the battery at each target temperature parameter is determined based on the target frequency.

[0012] Here, the imaginary zero-crossing frequency is dynamically determined through electrochemical impedance spectroscopy, and the real impedance value corresponding to this frequency is extracted as the target ohmic impedance, eliminating the interference of the reactance component on the impedance measurement. This provides high-precision input data for the calculation of the ohmic impedance coefficient, solves the impedance estimation distortion problem caused by differences in battery kinetic characteristics in the fixed-frequency measurement method in related technologies, and significantly improves the temperature control uniformity and safety of low-temperature pulse self-heating.

[0013] In one embodiment, the target temperature parameter includes a first temperature parameter and a second temperature parameter; the first temperature parameter is the temperature parameter for charging the battery when the charging temperature is lower than a preset temperature; the second temperature parameter is the temperature parameter for standard charging of the battery; determining the ohmic impedance coefficient of the battery at each target temperature parameter based on the target ohmic impedance includes:

[0014] Determine the first ohmic impedance corresponding to the first temperature parameter and the second ohmic impedance corresponding to the second temperature parameter;

[0015] The ohmic impedance coefficient is determined based on the first ohmic impedance, the second ohmic impedance, the first temperature parameter, and the second temperature parameter.

[0016] Here, by constructing a standardized calculation process, the ohmic impedance coefficient, which measures the sensitivity of battery ohmic impedance to temperature changes, is accurately measured. This coefficient serves as a core quantitative indicator characterizing the temperature sensitivity of individual battery internal resistance, constituting a precise classification criterion for differentiated pulse heating strategies. This overcomes the problem of insufficient adaptability to battery internal resistance temperature characteristics caused by using uniform parameters in related technologies, significantly improving heating efficiency and reducing energy loss, thus achieving precise control of individual differences in battery thermal management.

[0017] In one embodiment, the target temperature parameter includes a third temperature parameter and a fourth temperature parameter; both the third temperature parameter and the fourth temperature parameter are temperature parameters for charging the battery when the charging temperature is lower than a preset temperature; wherein, the value of the third temperature parameter is less than the value of the fourth temperature parameter; the step of determining the heating strategy of the battery based on the ohmic impedance coefficient includes:

[0018] Determine the first temperature range corresponding to the third temperature parameter and the second temperature range corresponding to the fourth temperature parameter;

[0019] A first heating strategy is used to determine the charging temperature of the battery within the first temperature range based on the ohmic impedance coefficient; or, a second heating strategy is used to determine the charging temperature of the battery within the second temperature range based on the ohmic impedance coefficient.

[0020] Here, by defining a third and a fourth temperature parameter (where the value of the third parameter is less than that of the fourth parameter), and matching specific heating strategies based on the ohmic impedance coefficient for the first temperature range corresponding to the third parameter and the second temperature range corresponding to the fourth parameter, precise heating adaptation is achieved. Compared to a single heating strategy, this improves heating efficiency and solves the safety risks and energy loss problems caused by temperature-heating strategy mismatch during low-temperature charging.

[0021] In one embodiment, determining the heating strategy of the battery based on the ohmic impedance coefficient includes:

[0022] If the ohmic impedance coefficient is less than the preset ohmic impedance threshold, then the first temperature range and the second temperature range are determined to correspond to the same target current parameter.

[0023] The heating strategy for the battery is determined to be heating the battery based on the target current parameter.

[0024] Here, for low-sensitivity batteries with an ohmic impedance coefficient less than the ohmic impedance threshold, the same target current parameter is set in the first and second temperature ranges, thereby achieving power stability and temperature rise rate control during the heating process.

[0025] In one embodiment, determining the heating strategy of the battery based on the ohmic impedance coefficient includes:

[0026] If the ohmic impedance coefficient is greater than or equal to a preset ohmic impedance threshold, then a first current parameter and a second current parameter for heating the battery are determined; the value of the first current parameter is less than the value of the second current parameter.

[0027] If the battery's charging temperature is within the first temperature range, the first heating strategy for the battery is determined to be heating the battery based on the first current parameter; or, if the battery's charging temperature is within the second temperature range, the second heating strategy for the battery is determined to be heating the battery based on the second current parameter.

[0028] Here, for highly sensitive batteries with an ohmic impedance coefficient greater than the ohmic impedance threshold, a lower first current parameter is set in the first temperature range, and a higher second current parameter is set in the second temperature range. This achieves a balance between safety and efficiency optimization, effectively shortening the heating time and improving heating efficiency compared to a single current strategy.

[0029] In one embodiment, determining the heating strategy of the battery based on the ohmic impedance coefficient includes:

[0030] Determine a first frequency parameter and a second frequency parameter for heating the battery;

[0031] When the charging temperature of the battery is within the first temperature range, the first heating strategy for the battery is determined to be heating the battery based on the first frequency parameter; or, when the charging temperature of the battery is within the second temperature range, the second heating strategy for the battery is determined to be heating the battery based on the second frequency parameter.

[0032] Here, for batteries with high or low ohmic impedance coefficients, a first power parameter is set in the first temperature range, and a second power parameter is set in the second temperature range, thereby achieving dynamic matching between power output and battery dynamic characteristics.

[0033] In one embodiment, the first temperature range includes a first temperature endpoint and a second temperature endpoint; the second temperature range includes a second temperature endpoint and a third temperature endpoint; the value of the second temperature endpoint is greater than the value of the first temperature endpoint, and the value of the second temperature endpoint is less than or equal to the value of the third temperature endpoint; the method further includes:

[0034] If the charging temperature of the battery is greater than or equal to the first temperature endpoint, the charging temperature of the battery is determined to be within the first temperature range.

[0035] The frequency at which the battery is heated is controlled is the first frequency parameter;

[0036] If the charging temperature of the battery is greater than or equal to the second temperature endpoint, the charging temperature of the battery is determined to be within the second temperature range.

[0037] The frequency at which the battery is heated is controlled is the second frequency parameter.

[0038] Here, the frequency can be dynamically adjusted based on the progressive relationship of the temperature range, using the frequency parameter when the imaginary part of the electrochemical impedance spectrum corresponding to the temperature at the left end of the temperature range is 0. This enables refined thermal management of the battery in different temperature ranges, thereby improving the technical problems of excessive energy consumption and uneven temperature rise caused by a single heating strategy, and effectively improving battery charging efficiency and safety.

[0039] In a second aspect, embodiments of the present invention provide an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the method according to any one of the preceding claims.

[0040] Thirdly, embodiments of the present invention provide a computer-readable storage medium storing a computer program configured to be executed by a processor to implement the method described in any of the preceding claims.

[0041] In embodiments of the present invention, by testing the electrochemical impedance spectroscopy of the battery at multiple target temperature parameters, the target ohmic impedance corresponding to each target temperature parameter is extracted, and the ohmic impedance coefficient reflecting the temperature sensitivity of the battery's ohmic impedance is calculated. This allows for the matching of differentiated heating strategies based on the value of the ohmic impedance coefficient. This method not only achieves precise matching between the heating strategy and the battery's inherent impedance-temperature characteristics but also effectively improves the efficiency of pulse self-heating, significantly shortens the heating time, and avoids the low heating efficiency caused by fixed heating strategies in related technologies due to differences in battery type. Attached Figure Description

[0042] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0043] Figure 1 A schematic flowchart of a battery heating strategy determination method provided in an embodiment of the present invention;

[0044] Figure 2 A schematic diagram illustrating the relationship between pulse currents at different temperatures is provided for embodiments of the present invention;

[0045] Figure 3 This is a schematic diagram of the battery temperature rise curve according to an embodiment of the present invention;

[0046] Figure 4 A schematic diagram of the device for determining the battery heating strategy provided in an embodiment of the present invention;

[0047] Figure 5 This is a schematic diagram of the hardware structure of an electronic device provided in an embodiment of the present invention. Detailed Implementation

[0048] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Furthermore, it should be understood that the specific embodiments described herein are only for illustration and explanation of the present invention and are not intended to limit the present invention. In the present invention, unless otherwise stated, directional terms such as "upper" and "lower" generally refer to the upper and lower positions of the device in actual use or operation, specifically the drawing directions in the accompanying drawings; while "inner" and "outer" refer to the outline of the device.

[0049] In low-temperature environments, the usable capacity of lithium-ion batteries decreases significantly, and the charging and discharging power drops sharply, resulting in reduced electric vehicle range, doubled charging time, and a drastic deterioration in user experience. Pulse self-heating utilizes the battery's internal resistance to generate heat, resulting in a rapid temperature rise rate and high temperature uniformity. Embodiments of this invention provide a method, device, and storage medium for determining a battery heating strategy. By quantifying the impedance-temperature relationship, it provides a basis for designing differentiated heating strategies for different battery types, making the temperature rise rate controllable. This addresses the technical problem of low heating efficiency caused by a single strategy, where a fixed current / frequency approach cannot adapt to battery types with significantly different ohmic impedance temperature characteristics.

[0050] Figure 1 A schematic flowchart of a battery heating strategy determination method provided in an embodiment of the present invention is shown below. Figure 1 As shown, an embodiment of the present invention provides a method for determining a battery heating strategy, including:

[0051] Step 101: Test the battery at multiple target temperature parameters to obtain the battery's electrochemical impedance spectrum.

[0052] In this embodiment, the target temperature parameter can be the operating temperature parameter for charging the battery. The target temperature parameter can be determined according to the actual situation and is not limited here. As an example, the value of the target temperature parameter can be any temperature value in the range of -30 to 25°C. For example, the value of the target temperature parameter can be 25°C, 10°C, 0°C, -10°C, -20°C, or -30°C.

[0053] In this embodiment, electrochemical impedance spectroscopy (EIS) can be a complex impedance spectrum formed by measuring the impedance response of a battery at different frequencies by applying a small-amplitude sinusoidal alternating current signal to the battery. Electrochemical impedance spectroscopy can be used to analyze the internal kinetic characteristics of the battery.

[0054] In this embodiment, the battery can be pre-treated before testing it under multiple target temperature parameters. Specifically, the state of charge (SOC) of the battery can be adjusted to the target SOC, which can be 50%. The battery is then left to stand for a first preset time to stabilize its voltage, which can be 2 hours. Finally, the battery is left to stand at a constant temperature under the target temperature parameters for a second preset time to ensure uniform internal temperature, which can be 4 to 6 hours.

[0055] In this embodiment, an AC signal with a frequency range of 0.1 Hz–100 kHz can be applied using an electrochemical workstation at the target temperature parameter, and the real part Z' and imaginary part Z” of the impedance at each frequency point can be recorded to obtain the electrochemical impedance spectrum at the current target temperature parameter. The value of the target temperature parameter can be gradually reduced. Specifically, the test can be performed point by point from high temperature (e.g., 25 °C) to low temperature (e.g., -30 °C) to reduce the influence of condensation.

[0056] Step 102: Determine the target ohmic impedance of the battery at each target temperature parameter based on electrochemical impedance spectroscopy.

[0057] In this embodiment, the target ohmic impedance can be the real part of the impedance when the battery exhibits purely resistive characteristics in the high-frequency region, characterizing the sum of ohmic losses from ion migration and electron conduction. As an example, the target ohmic impedance can be R... Ω The zero-crossing frequency f of the imaginary part can be located based on the recorded real part Z' and imaginary part Z' of the impedance at each frequency point. T And extract the corresponding real part impedance value. f T

[0058] In one embodiment, determining the target ohmic impedance of the battery at each target temperature parameter based on electrochemical impedance spectroscopy includes:

[0059] The target frequency corresponding to each target temperature parameter is determined based on electrochemical impedance spectroscopy.

[0060] The target ohmic impedance of the battery at each target temperature parameter is determined based on the target frequency.

[0061] In this embodiment, the target frequency can be the frequency of the characteristic frequency point corresponding to the zero imaginary part of the impedance in the electrochemical impedance spectrum. The target frequency can be determined according to the actual situation and is not limited here. As an example, the target frequency can be the frequency f at the zero-crossing point of the imaginary part. T Where T is the value of the target temperature parameter, for example, T = -30℃, f T f -30℃ .

[0062] In this embodiment, the process of determining the target frequency corresponding to each target temperature parameter based on electrochemical impedance spectroscopy can be determined according to actual conditions and is not limited here. As an example, the electrochemical impedance spectroscopy measured for each target temperature parameter can be plotted as an analytical graph (e.g., a Nyquist plot), where the horizontal axis of the Nyquist plot can be the real part Z' and the vertical axis can be the imaginary part -Z”; the target frequency f corresponding to the frequency point where -Z” = 0 in the Nyquist plot can be identified. T .

[0063] In this embodiment, the process of determining the target ohmic impedance of the battery at each target temperature parameter based on the target frequency can be determined according to the actual situation and is not limited here. As an example, when -Z” = 0, the precise intersection point coordinates (f) can be calculated by an interpolation algorithm. T ,R Ω Record the real part impedance value Z' corresponding to the intersection point as the target ohmic impedance R under each target temperature parameter. Ω .

[0064] Here, the imaginary zero-crossing frequency is dynamically determined through electrochemical impedance spectroscopy, and the real impedance value corresponding to this frequency is extracted as the target ohmic impedance, eliminating the interference of the reactance component on the impedance measurement. This provides high-precision input data for the calculation of the ohmic impedance coefficient, solves the impedance estimation distortion problem caused by differences in battery kinetic characteristics in the fixed-frequency measurement method in related technologies, and significantly improves the temperature control uniformity and safety of low-temperature pulse self-heating.

[0065] Step 103: Determine the ohmic impedance coefficient of the battery at each target temperature parameter based on the target ohmic impedance.

[0066] In this embodiment, the ohmic impedance coefficient can be used to quantify the battery ohmic impedance R. Ω The ohmic impedance coefficient is a sensitivity parameter that varies with temperature. It can be seen as the relative growth rate of ohmic impedance caused by a unit temperature drop within the range from the reference temperature to the low temperature. As an example, the ohmic impedance coefficient can be α, and the ohmic impedance coefficient of the battery under each target temperature parameter can be determined based on the ohmic impedance at the reference temperature, the ohmic impedance at the low temperature point within the low temperature range, and the temperature difference between the reference temperature and the low temperature point.

[0067] In one embodiment, the target temperature parameter includes a first temperature parameter and a second temperature parameter; the first temperature parameter is the temperature parameter for charging the battery when the charging temperature is lower than a preset temperature; the second temperature parameter is the temperature parameter for standard charging of the battery; determining the ohmic impedance coefficient of the battery at each target temperature parameter based on the target ohmic impedance includes:

[0068] Determine the first ohmic impedance corresponding to the first temperature parameter and the second ohmic impedance corresponding to the second temperature parameter;

[0069] The ohmic impedance coefficient is determined based on the first ohmic impedance, the second ohmic impedance, the first temperature parameter, and the second temperature parameter.

[0070] In this embodiment, the preset temperature can be the temperature characterizing the battery during low-temperature charging. The preset temperature can be determined according to actual conditions and is not limited here. As an example, the value of the preset temperature can be 10°C. The first temperature parameter can be determined according to actual conditions and is not limited here. As an example, the value of the first temperature parameter can be the low-temperature point T. low For example, T low The second temperature parameter can be -30℃. The specific temperature parameter can be determined based on the actual situation and is not limited here. As an example, the second temperature parameter can be the reference point temperature Tref, for example, Tref could be 25℃.

[0071] In this embodiment, the first ohmic impedance can be determined according to actual conditions and is not limited here. As an example, the first ohmic impedance can be the ohmic impedance R at a low temperature point. Ω (T low The second ohmic impedance can be determined based on the actual situation and is not limited here. As an example, the second ohmic impedance can be the ohmic impedance R of the reference point. Ω (Tref). The process of determining the first ohmic impedance corresponding to the first temperature parameter and the second ohmic impedance corresponding to the second temperature parameter can refer to the description above of determining the target ohmic impedance of the battery at each target temperature parameter based on electrochemical impedance spectroscopy, and will not be repeated here.

[0072] In this embodiment, the process of determining the ohmic impedance coefficient based on the first ohmic impedance, the second ohmic impedance, the first temperature parameter, and the second temperature parameter can be determined according to the actual situation and is not limited here. As an example, the first ohmic impedance and the second ohmic impedance can be subtracted to obtain a first difference; the second temperature parameter and the first temperature parameter can be subtracted to obtain a second difference; the second difference and the second ohmic impedance can be multiplied to obtain a first product; and the first difference and the first product can be divided to obtain the ohmic impedance coefficient.

[0073] Here, by constructing a standardized calculation process, the ohmic impedance coefficient, which measures the sensitivity of battery ohmic impedance to temperature changes, is accurately measured. This coefficient serves as a core quantitative indicator characterizing the temperature sensitivity of individual battery internal resistance, constituting a precise classification criterion for differentiated pulse heating strategies. This overcomes the problem of insufficient adaptability to battery internal resistance temperature characteristics caused by using uniform parameters in related technologies, significantly improving heating efficiency and reducing energy loss, thus achieving precise control of individual differences in battery thermal management.

[0074] Step 104: Determine the heating strategy for the battery based on the ohmic impedance coefficient.

[0075] In this embodiment, the sensitivity of the battery's ohmic impedance to temperature changes can be determined based on the ohmic impedance coefficient; then, the battery heating strategy can be determined based on the sensitivity of the battery's ohmic impedance to temperature changes. For example, if the sensitivity of the battery's ohmic impedance to temperature changes is high, the heating strategy can be determined to set different current parameters according to different temperature parameters; or, if the sensitivity of the battery's ohmic impedance to temperature changes is low, the heating strategy can be determined to set the same current parameter according to different temperature parameters.

[0076] In one embodiment, the target temperature parameters include a third temperature parameter and a fourth temperature parameter; both the third and fourth temperature parameters are temperature parameters for charging the battery when the charging temperature is lower than a preset temperature; wherein, the value of the third temperature parameter is less than the value of the fourth temperature parameter; determining the battery heating strategy based on the ohmic impedance coefficient includes:

[0077] Determine the first temperature range corresponding to the third temperature parameter, and the second temperature range corresponding to the fourth temperature parameter;

[0078] A first heating strategy that determines the battery's charging temperature to be in a first temperature range based on the ohmic impedance coefficient; or a second heating strategy that determines the battery's charging temperature to be in a second temperature range based on the ohmic impedance coefficient.

[0079] In this embodiment, the third temperature parameter can be determined according to actual conditions and is not limited here. As an example, the value of the third temperature parameter can be -30℃. The fourth temperature parameter can be determined according to actual conditions and is not limited here. As an example, the fourth temperature parameter can be -20℃.

[0080] In this embodiment, the process of determining the first temperature range corresponding to the third temperature parameter can be determined according to the actual situation and is not limited here. As an example, the first temperature range can be determined based on using the value of the third temperature parameter as the value of the first temperature endpoint and the value of the fourth temperature parameter as the value of the second temperature endpoint. The process of determining the second temperature range corresponding to the fourth temperature parameter can refer to the description of determining the first temperature range corresponding to the third temperature parameter, and will not be repeated here.

[0081] In this embodiment, the sensitivity of the battery's ohmic impedance to temperature changes can be determined based on the ohmic impedance coefficient. Then, based on this sensitivity, a heating strategy corresponding to different temperature ranges at which the battery's charging temperature is located can be determined. For example, if the battery's ohmic impedance is highly sensitive to temperature changes, the heating strategy can be determined to set different current parameters when the battery's charging temperature is in a first temperature range or a second temperature range. Alternatively, if the battery's ohmic impedance is low sensitive to temperature changes, the heating strategy can be determined to set the same current parameter when the battery's charging temperature is in a first temperature range or a second temperature range.

[0082] Here, by defining a third and a fourth temperature parameter (where the value of the third parameter is less than that of the fourth parameter), and matching specific heating strategies based on the ohmic impedance coefficient for the first temperature range corresponding to the third parameter and the second temperature range corresponding to the fourth parameter, precise heating adaptation is achieved. Compared to a single heating strategy, this improves heating efficiency and solves the safety risks and energy loss problems caused by temperature-heating strategy mismatch during low-temperature charging.

[0083] In one embodiment, determining the battery heating strategy based on the ohmic impedance coefficient includes:

[0084] If the ohmic impedance coefficient is less than the preset ohmic impedance threshold, then the first temperature range and the second temperature range are determined to correspond to the same target current parameter.

[0085] The battery heating strategy is determined to be heating the battery based on the target current parameter.

[0086] In this embodiment, the ohmic impedance threshold can be a critical value characterizing the sensitivity of the battery's ohmic impedance to temperature changes. Since the battery temperature rise during low-temperature pulse heating is mainly related to the battery's internal resistance at different temperatures, and the battery's internal resistance typically decreases with increasing temperature, the relationship between temperature and internal resistance is not linear. The battery's ohmic impedance coefficient α represents the sensitivity of the battery's ohmic impedance to temperature changes. By calculating the ohmic impedance coefficient α, the sensitivity of the ohmic impedance to temperature changes can be quantified. The ohmic impedance threshold can be determined according to actual conditions and is not limited here. As an example, the ohmic impedance threshold can be 1.0% / ℃.

[0087] In this embodiment, the target current parameter can be determined through actual heating tests based on the required heating rate, and is not limited here. As an example, the target current parameter can be a 4C current, that is, a current four times the battery capacity. If the ohmic impedance coefficient is less than a preset ohmic impedance threshold, the battery is a low-alpha battery. Since the target ohmic impedance of a low-alpha battery changes gradually with temperature, the first temperature range and the second temperature range correspond to the same target current parameter. When the battery's charging temperature crosses from the first temperature range to the second temperature range, the heating strategy maintains heating the battery based on the same target current parameter.

[0088] Here, for low-sensitivity batteries with an ohmic impedance coefficient less than the ohmic impedance threshold, the same target current parameter is set in the first and second temperature ranges, thereby achieving power stability and temperature rise rate control during the heating process.

[0089] In one embodiment, determining the battery heating strategy based on the ohmic impedance coefficient includes:

[0090] If the ohmic impedance coefficient is greater than or equal to the preset ohmic impedance threshold, then the first current parameter and the second current parameter for heating the battery are determined; the value of the first current parameter is less than the value of the second current parameter.

[0091] When the battery's charging temperature is within a first temperature range, the first heating strategy for the battery is determined to be heating the battery based on a first current parameter; or, when the battery's charging temperature is within a second temperature range, the second heating strategy for the battery is determined to be heating the battery based on a second current parameter.

[0092] In this embodiment, the first current parameter can be determined through actual heating tests based on the required heating rate, and is not limited here. As an example, the first current parameter can be a 1C current, i.e., a current equal to 1 times the battery capacity. The second current parameter can be determined through actual heating tests based on the required heating rate, and is not limited here. As an example, the second current parameter can be a 2C current, i.e., a current equal to 2 times the battery capacity. Because the battery's internal resistance decreases with increasing temperature, the value of the first current parameter is less than the value of the second current parameter.

[0093] In this embodiment, if the ohmic impedance coefficient is greater than the preset ohmic impedance threshold, the battery is a high α battery. Since the target ohmic impedance of the high α battery decreases sharply with temperature, a first current parameter for heating the battery is determined based on a third temperature parameter or a first temperature range, and a second current parameter for heating the battery is determined based on a fourth temperature parameter or a second temperature range.

[0094] In this embodiment, when the battery's charging temperature is within a first temperature range, the battery heating strategy is determined to be heating the battery based on a first current parameter; when the battery's charging temperature crosses from the first temperature range to a second temperature range, the battery heating strategy is determined to switch to heating the battery based on a second current parameter. It should be noted that the current parameter used to heat the battery is the same within the same temperature range.

[0095] Here, for highly sensitive batteries with an ohmic impedance coefficient greater than the ohmic impedance threshold, a lower first current parameter is set in the first temperature range, and a higher second current parameter is set in the second temperature range. This achieves a balance between safety and efficiency optimization, effectively shortening the heating time and improving heating efficiency compared to a single current strategy.

[0096] In one embodiment, determining the battery heating strategy based on the ohmic impedance coefficient includes:

[0097] Determine the first frequency parameter and the second frequency parameter for heating the battery;

[0098] When the battery's charging temperature is within a first temperature range, the first heating strategy for the battery is determined to be heating the battery based on a first frequency parameter; or, when the battery's charging temperature is within a second temperature range, the second heating strategy for the battery is determined to be heating the battery based on a second frequency parameter.

[0099] In this embodiment, the frequency f corresponding to the imaginary part of the impedance being 0 can be obtained based on the electrochemical impedance spectra at different temperatures. T Different batteries have different frequency values ​​at different temperatures. For example, when T is -30℃, f is determined by actual testing. -30℃ The first and second frequency parameters for heating the battery can be determined based on a third temperature parameter or a first temperature range, and the second frequency parameter can be determined based on a fourth temperature parameter or a second temperature range.

[0100] In this embodiment, when the battery's charging temperature is within a first temperature range, the battery heating strategy is determined to be heating the battery based on a first frequency parameter; when the battery's charging temperature crosses from the first temperature range to a second temperature range, the battery heating strategy is determined to switch to heating the battery based on a second frequency parameter. It should be noted that the frequency parameter used to heat the battery is the same within the same temperature range.

[0101] Here, for batteries with high or low ohmic impedance coefficients, a first power parameter is set in the first temperature range, and a second power parameter is set when the battery is in the second temperature range, thereby achieving dynamic matching between power output and battery dynamic characteristics.

[0102] In one embodiment, the first temperature range includes a first temperature endpoint and a second temperature endpoint; the second temperature range includes a second temperature endpoint and a third temperature endpoint; the value of the second temperature endpoint is greater than the value of the first temperature endpoint, and the value of the second temperature endpoint is less than or equal to the value of the third temperature endpoint; the method further includes:

[0103] If the battery's charging temperature is greater than or equal to the first temperature endpoint, the battery's charging temperature is determined to be within the first temperature range.

[0104] The frequency at which the battery is heated is set as the first frequency parameter;

[0105] If the battery's charging temperature is greater than or equal to the second temperature endpoint, the battery's charging temperature is determined to be within the second temperature range.

[0106] The frequency at which the battery is heated is the second frequency parameter.

[0107] In this embodiment, the first temperature endpoint can be the left endpoint of the first temperature range, and the second temperature endpoint can be the right endpoint of the first temperature range; the second temperature endpoint can also be the left endpoint of the second temperature range, and the third temperature range can be the right endpoint of the second temperature range.

[0108] In this embodiment, when the battery's charging temperature is greater than or equal to a first temperature endpoint, the battery's charging temperature is determined to be within a first temperature range. A first frequency parameter corresponding to the first temperature endpoint can be determined, and the frequency for heating the battery can be controlled to be the first frequency parameter. When the battery's charging temperature is greater than or equal to a second temperature endpoint, the battery's charging temperature is determined to be within a second temperature range. A second frequency parameter corresponding to the second temperature endpoint can be determined, and the frequency for heating the battery can be controlled to be the second frequency parameter.

[0109] Here, the frequency can be dynamically adjusted based on the progressive relationship of the temperature range, using the frequency parameter when the imaginary part of the electrochemical impedance spectrum corresponding to the temperature at the left end of the temperature range is 0. This enables refined thermal management of the battery in different temperature ranges, thereby improving the technical problems of excessive energy consumption and uneven temperature rise caused by a single heating strategy, and effectively improving battery charging efficiency and safety.

[0110] The following describes the battery heating strategy determination method provided by the embodiments of the present invention.

[0111] Pre-treatment of the battery: Adjust the battery to the target SOC (e.g., 50%) and allow it to stand for at least 2 hours to stabilize the voltage. Temperature adaptation of the battery: Place the battery in a temperature chamber and maintain it at the target test temperature for at least 4–6 hours to ensure uniform internal temperature. EIS testing of the battery: Test the electrochemical impedance spectroscopy of the battery at different temperatures (-30–25°C), testing point by point from high temperature (e.g., 25°C) to low temperature (e.g., -30°C) to reduce the influence of condensation. Temperature points may include: 25°C, 10°C, 0°C, -10°C, -20°C, -30°C, and the number of temperature points can be increased or decreased as needed.

[0112] Process the test data, for example, extract f T Plot a Nyquist diagram with the real part (Z') on the horizontal axis and the imaginary part (-Z”) on the vertical axis. Find the frequency point corresponding to -Z” = 0 in the Nyquist diagram to obtain the frequency f corresponding to the imaginary part of the impedance being 0. T , such as f -30℃ And the real impedance when the imaginary part of the impedance is 0, i.e., the ohmic impedance R. Ω The method for calculating the ohmic impedance coefficient (α) is shown in formula (1):

[0113]

[0114] Where α is the temperature coefficient of impedance; R Ω (T low R is the ohmic impedance at a low temperature (e.g., -30°C); Ω (Tref) is the ohmic impedance at a reference point (e.g., 25°C).

[0115] Based on the temperature coefficient of ohmic impedance (α), batteries are classified and differentiated pulse strategies are designed. Figure 2 A schematic diagram illustrating the relationship between pulse currents at different temperatures is provided for embodiments of the present invention, such as... Figure 2 As shown, high-α batteries (α≥1.0% / ℃): stepped temperature rise with variable current and frequency conversion. Triggering condition for current or frequency switching: the temperature value monitored by the temperature sensor reaches the endpoint of the temperature range, for example, a high-α battery operating at I1 current and f in the temperature range of -30℃ to -20℃. -30℃ Frequency heating; when the temperature rises to -20℃, the current becomes I2, and the frequency becomes f. -20℃ Continue heating, and so on. The current values ​​I1-I4 are determined based on the required heating rate and actual heating tests. Since the battery's internal resistance decreases with increasing temperature, I4>I3>I2>I1. Low-α battery (α<1.0% / ℃): constant current high-current frequency conversion. The current and characteristic frequency are the same within a temperature range. The frequency f is defined as the frequency corresponding to the imaginary part of the EIS impedance at the left endpoint of the temperature range being 0. T The characteristic frequency is denoted as .

[0116] Table 1 shows the frequency and current at different temperature ranges. As shown in Table 1, the current values ​​I1-I4 and the constant current are determined based on the required heating rate and actual heating tests. Since the battery internal resistance decreases with increasing temperature, I4>I3>I2>I1, and the current values ​​I1-I4 are, for example, 1C, 2C, 3C, and 4C; the constant current is, for example, 4C. Based on the electrochemical impedance spectra at different temperatures, the frequency f corresponding to the imaginary part of the impedance being 0 is obtained. T , such as f -30℃ The frequency is determined by actual testing, and different batteries have different frequency values ​​at different temperatures.

[0117] Table 1

[0118]

[0119] Taking the following two battery models as examples, αA≥1.0% / ℃, battery A is a high α battery, heated by a stepped temperature rise variable current frequency conversion method; αB≤1.0% / ℃, battery B is a low α battery, heated by a constant current high current frequency conversion method. Figure 3 This is a schematic diagram of the battery temperature rise curve according to an embodiment of the present invention, as shown below. Figure 3 As shown, the temperature rise rates of the two battery models are similar (taking the temperature rise curve at a constant frequency of 50Hz as an example).

[0120] During low-temperature pulse heating, the battery temperature rise is mainly related to the battery's internal resistance at different temperatures. The battery's internal resistance typically decreases with increasing temperature, but the relationship between temperature and internal resistance is not linear. The ohmic impedance coefficient α represents the battery's sensitivity to temperature changes in ohmic impedance. Calculating the ohmic impedance coefficient α is solely for quantifying this sensitivity. α is calculated based on different battery types, such as αA = 14% and αB = 0.6% as mentioned above. Therefore, a threshold of 1.0% / ℃ is set as a reference value. If more EIS results for various battery types are available, a more representative threshold can be determined.

[0121] This application embodiment achieves precise matching of thermoelectric parameters by segmenting the current / frequency; through differentiated design: high-alpha batteries perform "current boosting and frequency boosting" vs. low-alpha batteries perform "constant current boosting and frequency boosting", the temperature rise rate is controllable.

[0122] Figure 4 A schematic diagram of the structure of the device for determining the battery heating strategy provided in an embodiment of the present invention is shown below. Figure 4 As shown, the battery heating strategy determination device 400 includes:

[0123] Test module 401 is used to test the battery under multiple target temperature parameters to obtain the battery's electrochemical impedance spectrum;

[0124] The first determining module 402 is used to determine the target ohmic impedance of the battery at each target temperature parameter based on the electrochemical impedance spectroscopy.

[0125] The second determining module 403 is used to determine the ohmic impedance coefficient of the battery under each target temperature parameter based on the target ohmic impedance.

[0126] The third determining module 404 is used to determine the heating strategy of the battery based on the ohmic impedance coefficient.

[0127] In one embodiment, the first determining module 402 is further configured to determine the target frequency corresponding to each target temperature parameter based on the electrochemical impedance spectroscopy; and to determine the target ohmic impedance of the battery at each target temperature parameter based on the target frequency.

[0128] In one embodiment, the target temperature parameter includes a first temperature parameter and a second temperature parameter; the first temperature parameter is the temperature parameter for charging the battery when the charging temperature is lower than a preset temperature; the second temperature parameter is the temperature parameter for standard charging of the battery; the second determining module 403 is further used to determine the first ohmic impedance corresponding to the first temperature parameter and the second ohmic impedance corresponding to the second temperature parameter; and to determine the ohmic impedance coefficient based on the first ohmic impedance, the second ohmic impedance, the first temperature parameter and the second temperature parameter.

[0129] In one embodiment, the target temperature parameters include a third temperature parameter and a fourth temperature parameter; both the third and fourth temperature parameters are temperature parameters for charging the battery when the charging temperature is lower than a preset temperature; wherein, the value of the third temperature parameter is less than the value of the fourth temperature parameter; the third determining module 404 is further configured to determine a first temperature range corresponding to the third temperature parameter and a second temperature range corresponding to the fourth temperature parameter; determine a first heating strategy for the battery charging temperature to be in the first temperature range based on the ohmic impedance coefficient; or, determine a second heating strategy for the battery charging temperature to be in the second temperature range based on the ohmic impedance coefficient.

[0130] In one embodiment, the third determining module 404 is further configured to determine that if the ohmic impedance coefficient is less than a preset ohmic impedance threshold, the first temperature range and the second temperature range correspond to the same target current parameter; and determine that the battery heating strategy is to heat the battery based on the target current parameter.

[0131] In one embodiment, the third determining module 404 is further configured to determine a first current parameter and a second current parameter for heating the battery if the ohmic impedance coefficient is greater than or equal to a preset ohmic impedance threshold; the value of the first current parameter is less than the value of the second current parameter; when the battery charging temperature is in a first temperature range, the first heating strategy for the battery is determined to be heating the battery based on the first current parameter; or, when the battery charging temperature is in a second temperature range, the second heating strategy for the battery is determined to be heating the battery based on the second current parameter.

[0132] In one embodiment, the third determining module 404 is further configured to determine a first frequency parameter and a second frequency parameter for heating the battery; when the charging temperature of the battery is in a first temperature range, determine that the first heating strategy of the battery is to heat the battery based on the first frequency parameter; or, when the charging temperature of the battery is in a second temperature range, determine that the second heating strategy of the battery is to heat the battery based on the second frequency parameter.

[0133] In one embodiment, the first temperature range includes a first temperature endpoint and a second temperature endpoint; the second temperature range includes a second temperature endpoint and a third temperature endpoint; the value of the second temperature endpoint is greater than the value of the first temperature endpoint, and the value of the second temperature endpoint is less than or equal to the value of the third temperature endpoint; the third determining module 404 is further configured to determine that the charging temperature of the battery is in the first temperature range when the charging temperature of the battery is greater than or equal to the first temperature endpoint; control the frequency of heating the battery to a first frequency parameter; determine that the charging temperature of the battery is in the second temperature range when the charging temperature of the battery is greater than or equal to the second temperature endpoint; and control the frequency of heating the battery to a second frequency parameter.

[0134] To implement the method of the embodiments of the present invention, Figure 5 This is a schematic diagram of the hardware structure of an electronic device provided in an embodiment of the present invention, such as... Figure 5 As shown, this embodiment of the invention also provides an electronic device 50 that may include: a memory 501 for storing a computer program; and a processor 502 for implementing the method described above when executing the computer program. For example, the processor 502 may be used to implement the steps in any of the methods described above, which will not be elaborated further here.

[0135] It should be noted that the electronic devices provided in the above embodiments and the above method embodiments belong to the same concept, and their specific implementation process can be found in the method embodiments, which will not be repeated here.

[0136] Of course, in practical applications, such as Figure 5As shown, the electronic device 50 may further include at least one network interface 503. Various components in the electronic device are coupled together via a bus system 505. It is understood that the bus system 505 is used to implement communication between these components. In addition to a data bus, the bus system 505 also includes a power bus, a control bus, and a status signal bus. However, for clarity, in... Figure 5 Various buses are labeled as bus systems 505. There can be at least one processor 502. A network interface 503 is used for wired or wireless communication between the electronic device and other devices. The memory 501 in this embodiment is used to store various types of data to support the operation of the electronic device. The methods disclosed in the above embodiments of this invention can be applied to or implemented by the processor 502. The processor 502 may be an integrated circuit chip with signal processing capabilities. In implementation, each step of the above method can be completed by the integrated logic circuit of the hardware in the processor 502 or by instructions in software form. The processor 502 can be a general-purpose processor, a digital signal processor (DSP), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The processor 502 can implement or execute the methods, steps, and logic block diagrams disclosed in the embodiments of this invention. A general-purpose processor can be a microprocessor or any conventional processor, etc. The steps of the methods disclosed in the embodiments of this invention can be directly reflected in the combined execution of hardware and software modules in a microcontroller. The software module can reside in a storage medium located in memory 501. The processor 502 reads information from memory 501 and, in conjunction with its hardware, completes the steps of the aforementioned method. In an exemplary embodiment, the electronic device 50 can be implemented using one or more application-specific integrated circuits (ASICs), DSPs, programmable logic devices (PLDs), complex programmable logic devices (CPLDs), field-programmable gate arrays (FPGAs), general-purpose processors, controllers, microcontrollers (MCUs), microprocessors, or other electronic components to execute the aforementioned method.

[0137] Specifically, embodiments of the present invention provide a computer-readable storage medium storing a computer program thereon, such as a memory 501 storing the computer program, which can be executed by a processor 502 to complete the aforementioned method steps. The computer-readable storage medium may be a memory such as FRAM, ROM, PROM, EPROM, EEPROM, Flash Memory, magnetic surface memory, optical disc, or CD-ROM.

[0138] In addition, in the various embodiments of the present invention, each functional unit can be integrated into one processing unit, or each unit can be a separate unit, or two or more units can be integrated into one unit; the integrated unit can be implemented in hardware or in the form of hardware plus software functional units.

[0139] Those skilled in the art will understand that all or part of the steps of the above method embodiments can be implemented by hardware related to program instructions. The aforementioned program can be stored in a computer-readable storage medium. When the program is executed, it performs the steps of the above method embodiments. The aforementioned storage medium includes various media capable of storing program code, such as mobile storage devices, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0140] Alternatively, if the integrated units of this invention are implemented as software functional modules and sold or used as independent products, they can also be stored in a computer-readable storage medium. Based on this understanding, the technical solutions of the embodiments of this invention, or the parts that contribute to the prior art, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the methods of the various embodiments of this invention. The aforementioned storage medium includes various media capable of storing program code, such as mobile storage devices, ROM, RAM, magnetic disks, or optical disks.

[0141] The embodiments of the present invention have been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only for the purpose of helping to understand the method and core ideas of the present invention. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of the present invention. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A battery heating strategy determination method, characterized in that, The method comprises: testing the battery under a plurality of target temperature parameters to obtain an electrochemical impedance spectrum of the battery; determining a target ohmic impedance of the battery under each of the target temperature parameters based on the electrochemical impedance spectrum; determining an ohmic impedance coefficient of the battery under each of the target temperature parameters according to the target ohmic impedance; determining a heating strategy of the battery according to the ohmic impedance coefficient.

2. The method of claim 1, wherein, The determining of the target ohmic impedance of the battery under each of the target temperature parameters based on the electrochemical impedance spectrum comprises: determining a target frequency corresponding to each of the target temperature parameters based on the electrochemical impedance spectrum; determining the target ohmic impedance of the battery under each of the target temperature parameters according to the target frequency.

3. The method of claim 1, wherein, The target temperature parameters comprise a first temperature parameter and a second temperature parameter; the first temperature parameter is a temperature parameter for charging the battery when the charging temperature is less than a preset temperature; the second temperature parameter is a temperature parameter for standard charging of the battery; the determining of the ohmic impedance coefficient of the battery under each of the target temperature parameters according to the target ohmic impedance comprises: determining a first ohmic impedance corresponding to the first temperature parameter and a second ohmic impedance corresponding to the second temperature parameter; determining the ohmic impedance coefficient based on the first ohmic impedance, the second ohmic impedance, the first temperature parameter and the second temperature parameter.

4. The method of claim 1, wherein, The target temperature parameters comprise a third temperature parameter and a fourth temperature parameter; the third temperature parameter and the fourth temperature parameter are both temperature parameters for charging the battery when the charging temperature is less than a preset temperature; the value of the third temperature parameter is less than the value of the fourth temperature parameter; the determining of the heating strategy of the battery according to the ohmic impedance coefficient comprises: determining a first temperature interval corresponding to the third temperature parameter and a second temperature interval corresponding to the fourth temperature parameter; determining a first heating strategy of the battery according to the ohmic impedance coefficient, in which the charging temperature of the battery is in the first temperature interval; or determining a second heating strategy of the battery according to the ohmic impedance coefficient, in which the charging temperature of the battery is in the second temperature interval.

5. The method of claim 4, wherein, The determining of the heating strategy of the battery according to the ohmic impedance coefficient comprises: if the ohmic impedance coefficient is less than a preset ohmic impedance threshold, determining that the first temperature interval and the second temperature interval correspond to a same target current parameter; determining that the heating strategy of the battery is to heat the battery based on the target current parameter.

6. The method according to any of claims 4 or 5, characterized in that, The determining of the heating strategy of the battery according to the ohmic impedance coefficient comprises: if the ohmic impedance coefficient is greater than or equal to a preset ohmic impedance threshold, determining a first current parameter and a second current parameter for heating the battery; the value of the first current parameter is less than the value of the second current parameter. In a case where the charging temperature of the battery is in the first temperature interval, a first heating strategy of the battery is determined to heat the battery based on the first current parameter; or in a case where the charging temperature of the battery is in the second temperature interval, a second heating strategy of the battery is determined to heat the battery based on the second current parameter.

7. The method according to any of claims 5 or 6, characterized in that, The determining the heating strategy of the battery according to the ohmic impedance coefficient comprises: determining a first frequency parameter and a second frequency parameter for heating the battery; In a case where the charging temperature of the battery is in the first temperature interval, a first heating strategy of the battery is determined to heat the battery based on the first frequency parameter; or in a case where the charging temperature of the battery is in the second temperature interval, a second heating strategy of the battery is determined to heat the battery based on the second frequency parameter.

8. The method of claim 7, wherein, The first temperature interval comprises a first temperature endpoint and a second temperature endpoint; the second temperature interval comprises the second temperature endpoint and a third temperature endpoint; the value of the second temperature endpoint is greater than the value of the first temperature endpoint, and the value of the second temperature endpoint is less than or equal to the value of the third temperature endpoint; The method further comprises: In a case where the charging temperature of the battery is greater than or equal to the first temperature endpoint, it is determined that the charging temperature of the battery is in the first temperature interval; the frequency for heating the battery is controlled to be the first frequency parameter; In a case where the charging temperature of the battery is greater than or equal to the second temperature endpoint, it is determined that the charging temperature of the battery is in the second temperature interval; the frequency for heating the battery is controlled to be the second frequency parameter.

9. An electronic device comprising a memory, a processor, and a computer program stored on the memory and executable on the processor, characterized in that, The processor implements the method according to any one of claims 1-8 when executing the computer program.

10. A computer-readable storage medium, characterized in that, The computer readable storage medium stores a computer program configured to be executed by a processor to implement the method according to any one of claims 1-8.

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