Lithium-ion battery high-temperature fast-charging cooling method, device, equipment and storage medium

Abstract

The present application relates to a method, device, equipment and storage medium for high-temperature fast charging and cooling of lithium-ion batteries. The method includes: obtaining a capacity decay value of a battery system, comparing the capacity decay value with a preset capacity decay threshold, adjusting the first allowable temperature of the battery system according to the comparison result, and obtaining a second allowable temperature of the battery system; obtaining a charging curve from the first state of charge to the second state of charge according to the first temperature and the first state of charge of the battery system at the first moment; obtaining the second temperature of the battery system at the second moment according to the charging curve and the first temperature; comparing the second temperature with the second allowable temperature, and obtaining a cooling strategy according to the comparison result; obtaining the cooling time according to the cooling strategy and the heat value between the battery system and the charging environment, and cooling the battery system according to the cooling time, which can solve the problem of poor cooling performance during the charging process of lithium-ion batteries.

Description

Technical Field

[0001] The present invention relates to the field of thermal management technology for power batteries for new energy vehicles, and in particular to a method, device, equipment and storage medium for high-temperature fast charging and cooling of lithium-ion batteries. Background Art

[0002] With the continuous development of battery technology and the increasing attention paid to energy and environmental protection issues around the world, the new energy vehicle industry has developed rapidly. As a power source for new energy vehicles, lithium-ion batteries are an important part of new energy vehicles, and their performance directly affects the use of electric vehicles. Among all environmental factors, temperature has the greatest impact on the charging and discharging performance of lithium batteries. Although the operating temperature range of lithium-ion batteries is between -20°C and 45°C, when the operating temperature is higher than 40°C, the performance, capacity and life of lithium-ion batteries will be affected, and greater safety risks will be increased, and the charging and discharging capacity will be weakened. At present, a cooling system can be set on the power battery. The liquid cooling circulation system is used to cool the battery during the high-temperature charging stage and prohibit charging, and then charging is turned on after the battery system temperature drops. However, this method does not take into account the life cycle of the battery system. As the battery system ages, the increase in battery internal resistance may increase the impact of high temperature on the battery, resulting in the inability to cool the high-temperature battery system in time. Summary of the invention

[0003] Based on this, it is necessary to provide a lithium-ion battery high-temperature fast charging cooling method, device, equipment and storage medium to address the above technical problems, so as to improve the problem of poor cooling performance during the charging process of lithium-ion batteries.

[0004] On the one hand, a high-temperature fast-charge cooling method for a lithium-ion battery is provided, the high-temperature fast-charge cooling method for a lithium-ion battery comprising:

[0005] Acquire a capacity decay value of a battery system, compare the capacity decay value with a preset capacity decay threshold, adjust a first allowable temperature of the battery system according to the comparison result, and acquire a second allowable temperature of the battery system;

[0006] acquiring a charging curve from a first state of charge to a second state of charge according to a first temperature and a first state of charge (SOC) of the battery system at a first moment; acquiring a second temperature of the battery system at a second moment according to the charging curve and the first temperature; comparing the second temperature with the second allowable temperature, and acquiring a cooling strategy according to the comparison result;

[0007] A cooling time is obtained according to the cooling strategy and a heat value between the battery system and a charging environment, and the battery system is cooled according to the cooling time.

[0008] In one embodiment, the step of obtaining a second temperature of the battery system at a second moment according to the charging curve and the first temperature includes:

[0009] Acquire a charging current of the battery system at the second moment according to the charging curve;

[0010] The second temperature of the battery system at the second moment is obtained according to the charging current and basic properties of the battery system, wherein the basic properties of the battery system include: an internal resistance value of the battery system, a specific heat value of the battery system, and a mass quantity of the battery system.

[0011] In one embodiment, the step of comparing the second temperature with the second allowable temperature and obtaining a cooling strategy according to the comparison result includes:

[0012] determining whether the second temperature is greater than the second allowable temperature;

[0013] If yes, obtain a first cooling strategy;

[0014] If not, a second cooling strategy is obtained, and a second temperature of the battery system at a third moment is obtained.

[0015] In one embodiment, the step of obtaining the cooling strategy further includes:

[0016] determining whether the second temperature is greater than the second allowable temperature;

[0017] If yes, obtain a first cooling strategy;

[0018] If not, a second cooling strategy is obtained.

[0019] In one embodiment, the step of obtaining the cooling time according to the cooling strategy and the heat value between the battery system and the charging environment includes:

[0020] Determining whether the cooling strategy is the first cooling strategy;

[0021] If yes, then obtain the heat value generated from the first state of charge to the second state of charge, and obtain the heat value generated from the first temperature to the second temperature, wherein the heat value includes: the heat value of the battery system, and the heat exchange value between the battery system and the charging environment; according to the heat value and the cooling power, obtain the cooling time t_cool, which is mathematically expressed as:

[0022] t_cool=[(Q1-Q2)-(Q3-Q4)] / P

[0023] Among them, Q1 and Q3 represent the calorific value, Q2 and Q4 represent the heat exchange value, and P represents the cooling power.

[0024] In one embodiment, the capacity decay value is compared with a preset capacity decay threshold, and the first allowable temperature of the battery system is adjusted according to the comparison result. The step of obtaining the second allowable temperature of the battery system includes:

[0025] Determining whether the capacity decay value is greater than or equal to the capacity decay threshold;

[0026] If yes, subtract the preset temperature difference from the first allowable temperature to obtain the second allowable temperature;

[0027] If not, the first allowable temperature is set to the second allowable temperature.

[0028] In one embodiment, the step of cooling the battery system according to the cooling time includes:

[0029] The cooling time is subtracted from the time value corresponding to the second state of charge to obtain a cooling start time, and the battery system is cooled when the charging time reaches the cooling start time.

[0030] On the other hand, a lithium-ion battery high-temperature fast-charging cooling device is provided, and the lithium-ion battery high-temperature fast-charging cooling device comprises:

[0031] a maximum temperature adjustment module, configured to obtain a capacity decay value of a battery system, compare the capacity decay value with a preset capacity decay threshold, and adjust a first allowable temperature of the battery system according to the comparison result to obtain a second allowable temperature of the battery system;

[0032] a cooling strategy acquisition module, configured to acquire a charging curve from a first state of charge to a second state of charge according to a first temperature and a first state of charge of the battery system at a first moment; acquire a second temperature of the battery system at a second moment according to the charging curve and the first temperature; compare the second temperature with the second allowable temperature, and acquire a cooling strategy according to the comparison result;

[0033] A cooling module is used to obtain a cooling time according to the cooling strategy and a heat value between the battery system and a charging environment, and cool the battery system according to the cooling time.

[0034] In another aspect, a computer device is provided, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the computer program, the following steps are implemented:

[0035] Acquire a capacity decay value of a battery system, compare the capacity decay value with a preset capacity decay threshold, adjust a first allowable temperature of the battery system according to the comparison result, and acquire a second allowable temperature of the battery system;

[0036] acquiring a charging curve from the first state of charge to a second state of charge according to a first temperature and a first state of charge of the battery system at a first moment; acquiring a second temperature of the battery system at a second moment according to the charging curve and the first temperature; comparing the second temperature with the second allowable temperature, and acquiring a cooling strategy according to the comparison result;

[0037] A cooling time is obtained according to the cooling strategy and a heat value between the battery system and a charging environment, and the battery system is cooled according to the cooling time.

[0038] In another aspect, a computer-readable storage medium is provided, on which a computer program is stored, and when the computer program is executed by a processor, the following steps are implemented:

[0039] Acquire a capacity decay value of a battery system, compare the capacity decay value with a preset capacity decay threshold, adjust a first allowable temperature of the battery system according to the comparison result, and acquire a second allowable temperature of the battery system;

[0040] acquiring a charging curve from the first state of charge to a second state of charge according to a first temperature and a first state of charge of the battery system at a first moment; acquiring a second temperature of the battery system at a second moment according to the charging curve and the first temperature; comparing the second temperature with the second allowable temperature, and acquiring a cooling strategy according to the comparison result;

[0041] A cooling time is obtained according to the cooling strategy and a heat value between the battery system and a charging environment, and the battery system is cooled according to the cooling time.

[0042] The above-mentioned lithium-ion battery high-temperature fast charging cooling method, device, computer equipment and storage medium take into account the entire life cycle of the battery system, compare the capacity decay value of the battery system with a preset capacity decay threshold, thereby adjusting the first allowable temperature of the battery system and obtaining the second allowable temperature of the battery system; then, according to the first temperature and the first state of charge of the battery system at the first moment, obtain a charging curve from the first state of charge to the second state of charge; obtain the second temperature of the battery system at the second moment according to the charging curve and the first temperature; compare the second temperature with the second allowable temperature, and obtain a cooling strategy according to the comparison result; obtain the cooling time by using the cooling strategy and the heat value between the battery system and the charging environment, and cool the battery system according to the cooling time, so as to solve the problem of poor cooling performance of lithium-ion batteries during high-temperature fast charging. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 This is an application environment diagram of a lithium-ion battery high-temperature fast charging and cooling method in one embodiment;

[0044] Figure 2 A schematic diagram of a process for high-temperature fast charging and cooling a lithium-ion battery in one embodiment;

[0045] Figure 3 A schematic diagram of a process for obtaining a second temperature in one embodiment;

[0046] Figure 4 A schematic diagram of a process for obtaining a cooling strategy in an embodiment;

[0047] Figure 5 A schematic diagram of a flow chart for obtaining a cooling strategy in another embodiment;

[0048] Figure 6 A schematic diagram of a process for obtaining cooling time in one embodiment;

[0049] Figure 7 is a schematic diagram of a process for cooling a battery system in one embodiment;

[0050] Figure 8 is a schematic diagram of a flow chart of updating the second allowable temperature in one embodiment;

[0051] Fig. 9 It is a structural block diagram of a lithium-ion battery high-temperature fast-charging cooling device in another embodiment;

[0052] Fig.10 FIG. 4 is a diagram showing the internal structure of a computer device in one embodiment. DETAILED DESCRIPTION

[0053] In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0054] The present application provides a lithium-ion battery high-temperature fast-charge cooling method, which can be applied to Figure 1In the application environment shown. Among them, the terminal 102 communicates with the server 104 through the network. For example, a high-temperature fast charging cooling method for lithium-ion batteries provided in the present application can be applied to the scene of charging new energy vehicles, wherein new energy vehicles include PHEV (Plug in Hybrid Electric Vehicle) and EV (Electric Vehicle); lithium-ion batteries, as the power source of new energy vehicles, are an important part of new energy vehicles, and their performance directly affects the use of electric vehicles. Among all environmental factors, temperature has the greatest impact on the charging and discharging performance of lithium batteries. Although the operating temperature range of lithium-ion batteries is -20°C to 45°C, when the operating temperature is higher than 40°C, the performance, capacity and life of lithium-ion batteries will be affected, and a greater safety risk will be increased, and the charging and discharging capacity will be weakened. At present, a cooling system can be set on the power battery, and the battery is first cooled and charging is prohibited during the high-temperature charging stage through a liquid cooling circulation system, and charging is turned on after the battery system temperature drops. However, this method does not take into account the life cycle of the battery system. As the battery system ages, the increase in the internal resistance of the battery may increase the impact of high temperature on the battery, resulting in the inability to cool the high-temperature battery system in time. Therefore, this method takes into account the entire life cycle of the lithium-ion battery, and compares the capacity decay value of the battery system with a preset capacity decay threshold value, so as to adjust the first allowable temperature of the battery system and obtain the second allowable temperature of the battery system; then, based on the first temperature and the first state of charge of the battery system at the first moment, a charging curve from the first state of charge to the second state of charge is obtained; based on the charging curve and the first temperature, the second temperature of the battery system at the second moment is obtained; the second temperature of the battery system at the second moment is compared with the second allowable temperature, and a cooling strategy is obtained based on the comparison result; the cooling time is obtained by using the cooling strategy and the heat value between the battery system and the charging environment, and the battery system is cooled based on the cooling time, so as to solve the problem of poor cooling performance of lithium-ion batteries during high-temperature fast charging. In the specific implementation process, the terminal 102 can receive the specific time for executing the method from the server 104, and can also send the state of the battery system of the new energy vehicle and multiple parameter values ​​during the charging process from the terminal 102 to the server 104, so that the server 104 sends the specific time for executing the method after receiving the parameter information. Among them, the terminal 102 can be but not limited to various personal computers, laptops, smart phones, tablet computers, portable wearable devices or sub-servers, and the server 104 can be implemented as an independent server or a server cluster composed of multiple servers or a cloud computing platform.

[0055] In one embodiment, Figure 2 As shown, a lithium-ion battery high-temperature fast-charge cooling method is provided, comprising the following steps:

[0056] S1: obtaining a capacity decay value of a battery system, comparing the capacity decay value with a preset capacity decay threshold, adjusting a first allowable temperature of the battery system according to the comparison result, and obtaining a second allowable temperature of the battery system;

[0057] S2: acquiring a charging curve from the first state of charge to a second state of charge according to a first temperature and a first state of charge of the battery system at a first moment; acquiring a second temperature of the battery system at a second moment according to the charging curve and the first temperature; comparing the second temperature with the second allowable temperature, and acquiring a cooling strategy according to the comparison result;

[0058] S3: Acquire cooling time according to the cooling strategy and the heat value between the battery system and the charging environment, and cool the battery system according to the cooling time.

[0059] Through the above steps, the problem of poor cooling performance of lithium-ion batteries during high-temperature fast charging can be improved.

[0060] As the battery system is used and ages, its internal resistance will increase. Accordingly, if the same maximum allowable temperature is still used to determine whether to start the cooling process, the high temperature may not be controlled in a timely and effective manner, thereby worsening the safety environment of the battery system during high-temperature fast charging, and further accelerating the decay of the battery system. Therefore, in step S1, it is exemplified that the capacity decay value of the battery system is obtained, the capacity decay value is compared with a preset capacity decay threshold, and the first allowable temperature of the battery system is adjusted according to the comparison result to obtain the second allowable temperature of the battery system. For example, the maximum allowable temperature of the battery system can be adjusted according to the annual decay rate of the battery system capacity or the decay of 10,000 kilometers. In some embodiments, the maximum allowable temperature of the battery system can be adjusted according to the battery system. The first allowable temperature is set at the maximum allowable temperature at the time of leaving the factory, and the first allowable temperature is less than or equal to the maximum allowable temperature at the time of leaving the factory. For example, the first allowable temperature can be set to 45 degrees Celsius, and then it is determined whether the capacity decay value of the battery system is greater than or equal to the preset capacity decay threshold. If so, the value of the first allowable temperature is reduced to obtain the second allowable temperature. For example, the second allowable temperature can be set to 40 degrees Celsius. In this way, the maximum allowable temperature is reasonably adjusted according to the full life cycle of the battery system to avoid the situation where, under certain high temperature values, it is considered that cooling is not required when judging according to the original maximum allowable temperature or the first allowable temperature, so that the battery system is in a high-temperature fast charging working state for a long time, thereby reducing safety risks and increasing the service life of the battery system.

[0061] After obtaining the second allowable temperature, in order to determine under what conditions the battery system is cooled, in step S2, it is exemplarily described that, according to the first temperature and the first state of charge of the battery system at the first moment, a charging curve from the first state of charge to the second state of charge is obtained; the second temperature of the battery system at the second moment is obtained according to the charging curve and the first temperature; the second temperature is compared with the second allowable temperature, and a cooling strategy is obtained according to the comparison result. For example, the current moment when the battery system is charged can be taken as the first moment, the first temperature and the first state of charge values ​​at the first moment are obtained, and then the target SOC of charging is set as the second state of charge. After the first state of charge and the second state of charge are known, according to the battery management system (Battery Management The battery management system (BMS) calculates the remaining charging time and obtains the charging current curve, and then obtains the second temperature of the battery system at the second moment according to the charging current curve, and obtains the cooling strategy according to the numerical comparison between the second temperature and the second allowable temperature. In some implementation processes, the second moment can be selected by: selecting a time point between the first moment and the time corresponding to the second state of charge as the second moment. Preferably, 1 second can be added to the first moment as the second moment, so as to estimate the increase in the temperature of the battery system as the charging time increases from the first state of charge to the second state of charge. Furthermore, the method does not simply determine whether to start cooling based on the current temperature of the battery system, but predicts the temperature rise for a certain period of charging time during the charging process, and estimates the moment when the battery temperature will rise to the point where cooling is required before the actual temperature rises, so as to obtain a more effective cooling strategy.

[0062] After obtaining the cooling strategy, it is necessary to execute the cooling strategy at the appropriate time. In step S3, it is exemplified that the cooling time is obtained according to the cooling strategy and the heat value between the battery system and the charging environment, and the battery system is cooled according to the cooling time. For example, the heat generated by the battery system, the heat exchange between the battery system and the charging environment, and the cooling power of the cooling equipment are obtained, and the time required to cool the battery within a period of time is calculated, so as to control the temperature of the battery system within a reasonable range.

[0063] In some embodiments, Figure 3 As shown, the step of obtaining the second temperature of the battery system at the second moment according to the charging curve and the first temperature includes:

[0064] S11: acquiring a charging current of the battery system at the second moment according to the charging curve;

[0065] S12: Obtaining the second temperature of the battery system at the second moment according to the charging current and basic properties of the battery system, wherein the basic properties of the battery system include: an internal resistance value of the battery system, a specific heat value of the battery system, and a mass quantity of the battery system.

[0066] like Figure 3 As shown, in step S11, it is exemplarily explained that the charging current at the second moment is obtained according to the charging current curve. For example, according to the set first state of charge and second state of charge, the charging current curve is obtained from the BMS. The horizontal axis of the charging current curve can be time, and the vertical axis can be the current value. Therefore, the charging current corresponding to a certain moment can be obtained through the charging current curve.

[0067] like Figure 3 As shown, in step S12, it is exemplarily explained that the second temperature at the second moment is calculated according to the charging current and the basic properties of the battery system. For example, the mass value of the battery system, the internal resistance value of the battery system, and the specific heat value of the battery system are obtained, and the second temperature at the second moment can be calculated. The mathematical expression is:

[0068] T2=T1+Σ(I_t*I_t*R*Δt) / (C*m)

[0069] Wherein, T1 is the first temperature at the first moment, T2 is the second temperature at the second moment, I_t is the charging current at moment t, R is the internal resistance value of the battery system, C is the specific heat value of the battery system, m is the mass value of the battery system, Δt is the minimum time value between the first moment and the second moment, and Σ(·) is the summation function.

[0070] In some implementations, Δt can be set to 1 second.

[0071] In order to obtain the cooling strategy, the second temperature needs to be compared with the second allowed temperature, such as Figure 4 As shown, in some embodiments, the step of comparing the second temperature with the second allowable temperature and acquiring the cooling strategy according to the comparison result includes:

[0072] S21: Determine whether the second temperature is greater than the second allowable temperature;

[0073] S22: If yes, obtain a first cooling strategy;

[0074] S23: If not, obtain a second cooling strategy, and obtain a second temperature of the battery system at a third moment.

[0075] like Figure 4As shown, in step S21 to step S23, it is exemplified that different cooling strategies are obtained according to the results of the second temperature and the second allowable temperature. For example, when the second temperature is greater than the second allowable temperature, it can be considered that the charging process at this moment needs to be cooled, and the first cooling strategy is obtained. If the second temperature is less than the second allowable temperature, it is considered that the charging process at this moment does not need to be cooled. However, in addition to comparing the temperature at a certain moment with the second allowable temperature to obtain a cooling strategy, this method also predicts the battery system temperature within a period of time during the charging process. Therefore, when the second temperature at the second moment is less than the second allowable temperature, in order to further predict whether the second temperature at a subsequent time is greater than the second allowable temperature, a third moment can be selected between the first state of charge and the second state of charge, and the second temperature value corresponding to the third moment is calculated according to the charging current corresponding to the third moment.

[0076] After obtaining the second temperature at the third moment, the second temperature can be further compared with the second allowable temperature, such as Figure 5 As shown, the step of obtaining the cooling strategy also includes:

[0077] S31: Determine whether the second temperature is greater than the second allowable temperature;

[0078] S32: If yes, obtain a first cooling strategy;

[0079] S33: If not, obtain a second cooling strategy.

[0080] Through the above steps, the temperature of more charging time periods can be further judged, thereby improving the rationality and timeliness of cooling the battery system.

[0081] like Figure 5 As shown, in step S31 to step S33, it is exemplarily explained that the cooling strategy is updated according to the comparison result of the second temperature at the third moment and the second allowable temperature. For example, when the second temperature corresponding to the third moment is greater than the second allowable temperature, it is considered that the battery system needs to be cooled at this moment, and the first cooling strategy is obtained. Otherwise, the second cooling strategy is obtained. In some implementation processes, the temperature can be increased by 0.5 degrees Celsius or 1 degree Celsius according to the temperature accuracy and the change of the charging current. In this way, the temperature of different charging time ranges can be predicted. And the cooling strategy is obtained in advance.

[0082] After obtaining the cooling strategy, you need to set the cooling time, such as Figure 6 As shown, according to the cooling strategy and the heat value between the battery system and the charging environment, the step of obtaining the cooling time includes:

[0083] S41: Determine whether the cooling strategy is the first cooling strategy;

[0084] S42: If yes, then obtain the heat value generated from the first state of charge to the second state of charge, and obtain the heat value generated from the first temperature to the second temperature, wherein the heat value includes: the heat value of the battery system, and the heat exchange value between the battery system and the charging environment; according to the heat value and the cooling power, obtain the cooling time t_cool, which is mathematically expressed as:

[0085] t_cool=[(Q1-Q2)-(Q3-Q4)] / P

[0086] Among them, Q1 and Q3 represent the calorific value, Q2 and Q4 represent the heat exchange value, and P represents the cooling power.

[0087] like Figure 6 As shown, in step S41 to step S42, it is exemplarily explained that the duration of starting cooling is calculated according to the heat value and the cooling power. For example, when the cooling strategy is the first cooling strategy, the battery system needs to be cooled, and the heat value Q1 of the battery system from the first state of charge to the second state of charge and the heat exchange value Q2 between the battery system and the charging environment are obtained, and then the heat value Q3 of the battery system and the heat exchange value Q4 between the battery system and the charging environment are obtained during the period from the first temperature rising to the second temperature greater than the second allowable temperature, and then the cooling time t_cool required to start the cooling process is obtained according to the cooling power P of the cooling device corresponding to the battery system. The mathematical expression is:

[0088] t_cool=[(Q1-Q2)-(Q3-Q4)] / P

[0089] Among them, the mathematical expression of the heat generated by the battery system is:

[0090] Q1=Σ(I_t*I_t*R*Δt)

[0091] Wherein, I_t is the charging current at time t, R is the internal resistance value of the battery system, Δt is the minimum time value between the first time and the second time, and Σ(·) is the summation function.

[0092] The mathematical expression of the heat exchange Q2 between the battery system and the charging environment is:

[0093] Q2=Σ(ΔQ0)

[0094] Wherein, ΔQ0 represents the difference between the temperature of the battery system and the ambient temperature within Δt time (eg, 1 second), and the specific value can be obtained according to the model of the battery system during the actual implementation process.

[0095] For Q3 and Q4, the above formula can also be used for calculation, but it is necessary to select different time lengths and sum the current values ​​within the time lengths. In this way, the time length for starting the cooling process can be calculated.

[0096] After obtaining the cooling time, you need to calculate when to start the cooling, such as Figure 7 As shown, the step of cooling the battery system according to the cooling time includes:

[0097] S51: Subtract the cooling time from the time value corresponding to the second state of charge to obtain a cooling start time, and cool the battery system when the charging time reaches the cooling start time.

[0098] Through the above steps, it is possible to calculate when to start cooling according to the cooling time required to start the cooling process during the charging time.

[0099] like Figure 7 As shown, in step S51, it is exemplarily explained that the cooling time is subtracted from the time value corresponding to the second state of charge to obtain the cooling start time, and the battery system is cooled when the charging time reaches the cooling start time. For example, the cooling time is t_cool, the time value corresponding to the second state of charge is t_soc2, and the cooling start time is t_start, then t_start = t_soc2-t_cool, if t_start is greater than or equal to 0, the cooling process is started when charging reaches t_start, if t_start is less than 0, the cooling is started immediately, and in some implementation processes, the battery cooling operation is stopped when the new energy vehicle stops charging or the SOC is charged to 100%.

[0100] In some embodiments, the second allowable temperature needs to be updated according to the capacity decay value of the battery system, such as Figure 8 As shown, the capacity decay value is compared with a preset capacity decay threshold, and the first allowable temperature of the battery system is adjusted according to the comparison result. The step of obtaining the second allowable temperature of the battery system includes:

[0101] S61: Determine whether the capacity decay value is greater than or equal to the capacity decay threshold;

[0102] S62: If yes, subtract the preset temperature difference from the first allowable temperature to obtain the second allowable temperature;

[0103] S63: If not, setting the first allowable temperature to the second allowable temperature.

[0104] Through the above steps, the life cycle of the battery system can be considered, and the second allowable temperature of the battery system can be updated according to its attenuated capacity, so as to reasonably adjust the maximum allowable temperature, so as to avoid the situation where, under a certain high temperature value, it is judged according to the original maximum allowable temperature or the first allowable temperature that no cooling treatment is required at this time, thereby the battery system is in a high-temperature fast-charging working state for a long time, thereby reducing safety risks and increasing the service life of the battery system.

[0105] like Figure 8 As shown, in step S61 to step S63, it is exemplarily explained that the capacity decay value is compared with the capacity decay threshold to obtain the second allowable temperature. For example, the annual decay rate of the battery system capacity or the decay rate per 10,000 kilometers can be used as the capacity decay value E1. When the capacity decay value E1 is greater than or equal to the preset capacity decay threshold E2, the first allowable temperature is subtracted from the preset temperature difference to obtain the second allowable temperature. In some implementations, the temperature difference can be set to a value between 2 and 5 degrees Celsius. If the capacity decay value E1 is less than the capacity decay threshold E2, the value of the first allowable temperature is directly used as the value of the second allowable temperature.

[0106] In one embodiment, Fig. 9 As shown, a lithium-ion battery high-temperature fast-charging cooling device is provided, characterized in that it includes:

[0107] a maximum temperature adjustment module, configured to obtain a capacity decay value of a battery system, compare the capacity decay value with a preset capacity decay threshold, and adjust a first allowable temperature of the battery system according to the comparison result to obtain a second allowable temperature of the battery system;

[0108] a cooling strategy acquisition module, configured to acquire a charging curve from a first state of charge to a second state of charge according to a first temperature and a first state of charge of the battery system at a first moment; acquire a second temperature of the battery system at a second moment according to the charging curve and the first temperature; compare the second temperature with the second allowable temperature, and acquire a cooling strategy according to the comparison result;

[0109] A cooling module is used to obtain a cooling time according to the cooling strategy and a heat value between the battery system and a charging environment, and cool the battery system according to the cooling time.

[0110] In the maximum temperature adjustment module, it is exemplified that the capacity attenuation value of the battery system is obtained, the capacity attenuation value is compared with the preset capacity attenuation threshold, the first allowable temperature of the battery system is adjusted according to the comparison result, and the second allowable temperature of the battery system is obtained. For example, the annual attenuation rate of the battery system capacity or the attenuation after 10,000 kilometers can be combined to adjust the maximum allowable temperature of the battery system according to the situation. In some embodiments, the first allowable temperature can be set according to the maximum allowable temperature of the battery system at the time of leaving the factory, and the first allowable temperature is less than or equal to the maximum allowable temperature at the time of leaving the factory. For example, the first allowable temperature can be set to 45 degrees Celsius or 50 degrees Celsius, and then it is determined whether the capacity attenuation value of the battery system is greater than or equal to the preset capacity attenuation threshold. If so, the value of the first allowable temperature is reduced to obtain the second allowable temperature. For example, the second allowable temperature can be set to 40 degrees Celsius or 45 degrees Celsius. In this way, according to the full life cycle of the battery system, the maximum allowable temperature is reasonably adjusted to avoid the situation where, under a certain high temperature value, it is considered that cooling is not required at this time when judging according to the original maximum allowable temperature or the first allowable temperature, so that the battery system is in a high-temperature fast charging working state for a long time, thereby reducing safety risks and increasing the service life of the battery system.

[0111] In the cooling strategy acquisition module, it is exemplified that, according to the first temperature and the first state of charge of the battery system at the first moment, a charging curve from the first state of charge to the second state of charge is obtained; according to the charging curve and the first temperature, the second temperature of the battery system at the second moment is obtained; the second temperature is compared with the second allowable temperature, and the cooling strategy is obtained according to the comparison result. For example, the current moment when the battery system is charged can be taken as the first moment, the first temperature and the first state of charge values ​​at the first moment are obtained, and then the charging target SOC is set as the second state of charge. After the first state of charge and the second state of charge are known, the remaining charging time is calculated according to the battery management system and the charging current curve is obtained, and then the second temperature of the battery system at the second moment is obtained according to the charging current curve, and according to the second temperature and the second state of charge, the cooling strategy is obtained. 2. Comparing the numerical values ​​of the allowed temperatures to obtain a cooling strategy. In some implementation processes, the method for selecting the second moment may be: selecting a time point between the first moment and the time corresponding to the second state of charge as the second moment. Preferably, 1 second or 0.5 second may be added to the first moment as the second moment, so as to estimate the increase in battery system temperature as the charging time increases from the first state of charge to the second state of charge. Furthermore, the method does not simply determine whether to start cooling based on the current temperature of the battery system, but predicts the temperature rise for a certain period of charging time during the charging process, and estimates the moment when the battery temperature will rise to a state requiring cooling before the actual temperature rises, so as to obtain a more effective cooling strategy.

[0112] In the cooling module, it is exemplified that the cooling time is obtained according to the cooling strategy and the heat value between the battery system and the charging environment, and the battery system is cooled according to the cooling time. For example, the heat generated by the battery system, the heat exchange between the battery system and the charging environment, and the cooling power of the cooling equipment are obtained, and the time required to cool the battery within a period of time is calculated. Then, the time to start cooling is determined according to the time required for cooling, so as to control the temperature of the battery system within a reasonable range.

[0113] The above-mentioned device can be applied to the scenario of high-temperature fast charging of new energy vehicles, and compares the capacity attenuation value of the battery system with the preset capacity attenuation threshold value to adjust the first allowable temperature of the battery system and obtain the second allowable temperature of the battery system; then, according to the first temperature and the first state of charge of the battery system at the first moment, obtain the charging curve from the first state of charge to the second state of charge; according to the charging curve and the first temperature, obtain the second temperature of the battery system at the second moment; compare the second temperature with the second allowable temperature, and obtain a cooling strategy according to the comparison result; obtain the cooling time by using the cooling strategy and the heat value between the battery system and the charging environment, and cool the battery system according to the cooling time, so as to solve the problem of poor cooling performance of lithium-ion batteries during high-temperature fast charging.

[0114] For the specific definition of the lithium-ion battery high-temperature fast charging and cooling device, please refer to the definition of the lithium-ion battery high-temperature fast charging and cooling method above, which will not be repeated here. Each module in the above-mentioned lithium-ion battery high-temperature fast charging and cooling device can be implemented in whole or in part through software, hardware and a combination thereof. The above-mentioned modules can be embedded in or independent of the processor in the computer device in the form of hardware, or can be stored in the memory of the computer device in the form of software, so that the processor can call and execute the operations corresponding to the above modules.

[0115] In one embodiment, a computer device is provided. The computer device may be a server, and its internal structure diagram may be as follows: Fig.10 As shown. The computer device includes a processor, a memory, a network interface and a database connected through a system bus. Among them, the processor of the computer device is used to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system, a computer program and a database. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The database of the computer device is used to store data of various parameters during the high-temperature fast charging and cooling process. The network interface of the computer device is used to communicate with an external terminal through a network connection. When the computer program is executed by the processor, a high-temperature fast charging and cooling method for a lithium-ion battery is implemented.

[0116] Those skilled in the art will understand that Fig.10 The structure shown in the figure is only a block diagram of a part of the structure related to the solution of the present application, and does not constitute a limitation on the computer device to which the solution of the present application is applied. The specific computer device may include more or fewer components than those shown in the figure, or combine certain components, or have a different arrangement of components.

[0117] In one embodiment, a computer device is provided, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the following steps when executing the computer program:

[0118] Acquire a capacity decay value of a battery system, compare the capacity decay value with a preset capacity decay threshold, adjust a first allowable temperature of the battery system according to the comparison result, and acquire a second allowable temperature of the battery system;

[0119] acquiring a charging curve from the first state of charge to a second state of charge according to a first temperature and a first state of charge of the battery system at a first moment; acquiring a second temperature of the battery system at a second moment according to the charging curve and the first temperature; comparing the second temperature with the second allowable temperature, and acquiring a cooling strategy according to the comparison result;

[0120] A cooling time is obtained according to the cooling strategy and a heat value between the battery system and a charging environment, and the battery system is cooled according to the cooling time.

[0121] In one embodiment, a computer readable storage medium is provided, on which a computer program is stored, and when the computer program is executed by a processor, the following steps are implemented:

[0122] Acquire a capacity decay value of a battery system, compare the capacity decay value with a preset capacity decay threshold, adjust a first allowable temperature of the battery system according to the comparison result, and acquire a second allowable temperature of the battery system;

[0123] acquiring a charging curve from the first state of charge to a second state of charge according to a first temperature and a first state of charge of the battery system at a first moment; acquiring a second temperature of the battery system at a second moment according to the charging curve and the first temperature; comparing the second temperature with the second allowable temperature, and acquiring a cooling strategy according to the comparison result;

[0124] A cooling time is obtained according to the cooling strategy and a heat value between the battery system and a charging environment, and the battery system is cooled according to the cooling time.

[0125] Those skilled in the art can understand that all or part of the processes in the above-mentioned embodiment methods can be completed by instructing the relevant hardware through a computer program, and the computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to memory, storage, database or other media used in the embodiments provided in this application can include non-volatile and / or volatile memory. Non-volatile memory can include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM) or flash memory. Volatile memory can include random access memory (RAM) or external cache memory. As an illustration and not limitation, RAM is available in many forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDRSDRAM), enhanced SDRAM (ESDRAM), synchronous link (Synchlink) DRAM (SLDRAM), memory bus (Rambus) direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and memory bus dynamic RAM (RDRAM).

[0126] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0127] The above-mentioned embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application shall be subject to the attached claims.

Claims

1. A high temperature fast charging cooling method for lithium ion batteries, characterized in that: include: Acquire a capacity decay value of a battery system, compare the capacity decay value with a preset capacity decay threshold, adjust a first allowable temperature of the battery system according to the comparison result, and acquire a second allowable temperature of the battery system, wherein the first allowable temperature is less than or equal to a maximum allowable temperature of the battery system at the time of leaving the factory; The current moment when the battery system is charged is taken as the first moment, and according to the first temperature and the first state of charge of the battery system at the first moment, the target SOC of charging is set as the second state of charge, and a charging curve from the first state of charge to the second state of charge is obtained; a time point is selected during the period of charging from the first state of charge to the second state of charge as the second moment, and according to the charging curve, the first temperature, the mass value of the battery system, the internal resistance value of the battery system and the specific heat value of the battery system, the second temperature of the battery system at the second moment is calculated; comparing the second temperature with the second allowable temperature, and determining whether cooling is required according to the comparison result; If it is determined that cooling is required, the cooling time is calculated based on the heat values ​​generated from the first state of charge to the second state of charge and from the first temperature rising to the second temperature and the cooling power of the cooling equipment, and the heat values ​​include: the heat value of the battery system, the heat exchange value between the battery system and the charging environment, and the battery system is cooled according to the cooling time.

2. The high temperature fast charging cooling method for lithium ion batteries according to claim 1, characterized in that: The step of calculating the second temperature of the battery system at the second moment according to the charging curve, the first temperature, the mass value of the battery system, the internal resistance value of the battery system and the specific heat value of the battery system comprises: Acquire a charging current of the battery system at the second moment according to the charging curve; The second temperature of the battery system at the second moment is calculated according to the charging current, the first temperature, the internal resistance value of the battery system, the specific heat value of the battery system and the mass quantity of the battery system.

3. The lithium-ion battery high-temperature fast-charge cooling method according to claim 1, characterized in that: The step of comparing the second temperature with the second allowable temperature and determining whether cooling is required according to the comparison result comprises: determining whether the second temperature is greater than the second allowable temperature; If so, it is determined that cooling is required; If not, it is determined that cooling is not required, and a third time is selected between the first state of charge and the second state of charge and after the second time, and a second temperature of the battery system at the third time is obtained.

4. The high temperature fast charging cooling method for lithium ion batteries according to claim 3, characterized in that: After obtaining the second temperature of the battery system at the third moment, the method further includes: determining whether the second temperature is greater than the second allowable temperature; If so, it is determined that cooling is required; If not, it is determined that cooling is not required.

5. The lithium-ion battery high-temperature fast-charge cooling method according to claim 1, characterized in that: The step of calculating the cooling time according to the heat value generated during the period from the first state of charge to the second state of charge and during the period from the first temperature rising to the second temperature and the cooling power of the cooling device comprises: The heat value generated from the first state of charge to the second state of charge is obtained, and the heat value generated from the first temperature to the second temperature is obtained, wherein the heat value includes: the heat value of the battery system, and the heat exchange value between the battery system and the charging environment; according to the heat value and the cooling power, the cooling time t_cool is obtained, which is mathematically expressed as: t_cool=[(Q1-Q2)-(Q3-Q4)] / P Among them, Q1 and Q3 represent the calorific value, Q2 and Q4 represent the heat exchange value, and P represents the cooling power.

6. The lithium-ion battery high-temperature fast-charge cooling method according to claim 1, characterized in that: The step of comparing the capacity decay value with a preset capacity decay threshold, adjusting the first allowable temperature of the battery system according to the comparison result, and obtaining the second allowable temperature of the battery system includes: Determining whether the capacity decay value is greater than or equal to the capacity decay threshold; If yes, subtract the preset temperature difference from the first allowable temperature to obtain the second allowable temperature; If not, the first allowable temperature is set to the second allowable temperature.

7. The lithium-ion battery high-temperature fast-charge cooling method according to claim 1, characterized in that: The step of cooling the battery system according to the cooling time comprises: The cooling time is subtracted from the time value corresponding to the second state of charge to obtain a cooling start time, and the battery system is cooled when the charging time reaches the cooling start time.

8. A lithium-ion battery high-temperature fast-charging cooling device, characterized in that: include: a maximum temperature adjustment module, used to obtain a capacity decay value of a battery system, compare the capacity decay value with a preset capacity decay threshold, and adjust a first allowable temperature of the battery system according to the comparison result to obtain a second allowable temperature of the battery system, wherein the first allowable temperature is less than or equal to a maximum allowable temperature of the battery system at the time of leaving the factory; a cooling strategy acquisition module, configured to take the current moment when the battery system is being charged as a first moment, set a target SOC for charging as a second state of charge according to a first temperature and a first state of charge of the battery system at the first moment, and acquire a charging curve from the first state of charge to the second state of charge; select a time point during charging from the first state of charge to the second state of charge as a second moment, and calculate a second temperature of the battery system at the second moment according to the charging curve, the first temperature, a mass value of the battery system, an internal resistance value of the battery system, and a specific heat value of the battery system; comparing the second temperature with the second allowable temperature, and determining whether cooling is required according to the comparison result; The cooling module is used to calculate the cooling time according to the heat values ​​generated from the first state of charge to the second state of charge and from the first temperature to the second temperature and the cooling power of the cooling equipment if it is determined that cooling is required. The heat values ​​include: the heat value of the battery system, the heat exchange value between the battery system and the charging environment, and the battery system is cooled according to the cooling time.

9. A computer device comprising a memory, a processor and a computer program stored in the memory and executable on the processor, characterized in that: When the processor executes the computer program, the steps of the lithium-ion battery high-temperature fast charging and cooling method according to any one of claims 1 to 7 are implemented.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the lithium-ion battery high-temperature fast charging and cooling method according to any one of claims 1 to 7 are implemented.

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