A lithium battery temperature control method, system, device and readable storage medium

Abstract

The present application discloses a temperature control method, system, device and readable storage medium for a lithium battery. The method includes: when the lithium battery meets the preset heating condition, heating the lithium battery according to a preset heating period; after the heating process is completed in the current heating period, monitoring whether the heated lithium battery meets the heating condition. If it meets the heating condition, determine the second duty ratio corresponding to the next heating period according to the first duty ratio corresponding to the current heating period and a preset adjustment strategy, and judge whether the second duty ratio meets the preset operating condition; if the second duty ratio meets the operating condition, enter the next heating period, and continue to heat the lithium battery according to the second duty ratio until the lithium battery does not meet the heating condition or the duty ratio corresponding to the heating period to be entered does not meet the operating condition, then stop heating. The present application can always control the self-heating process within a favorable range, and maximize the utilization of the battery capacity at low temperatures.

Description

Technical Field

[0001] The present application relates to the technical field of battery charging, and more specifically, to a temperature control method, system, device and readable storage medium for lithium batteries. Background Art

[0002] The operating temperature of lithium-ion batteries affects the low-temperature performance of lithium batteries. The lithium ions in lithium batteries have poor activity at low temperatures, resulting in a reduction in the capacity released by lithium batteries at low temperatures. Therefore, the performance of lithium batteries under low-temperature conditions will decline, manifested as an extended charging time, a reduced charge and discharge capacity, a smaller battery capacity, and a fast power loss rate, thereby affecting energy supply. The normal operating temperature of conventional lithium-ion batteries is between -20°C and 60°C. However, generally, the performance of lithium batteries will decline when the temperature is below 0°C, and the discharge capacity will decrease accordingly. Therefore, the normal operating temperature range for the full performance of lithium-ion batteries is usually 0 to 40°C.

[0003] At present, the common solution adopted by electric vehicle manufacturers in the market for the poor activity of lithium ions at low temperatures and the resulting reduction in released capacity is to discharge the lithium battery, and heat the lithium battery to room temperature by a heating film so that the capacity of the lithium battery can be released normally. However, for small devices such as PDAs or mobile phones, the overall capacity of the lithium batteries equipped on them is relatively small. If the lithium battery's own power is used to heat the lithium battery to room temperature, it will cause the lithium battery to consume a large amount of power for heating. Even when the set temperature is reached, the actual available power is very small, and the power consumed by heating the lithium battery is greater than the power that cannot be fully released due to the temperature drop.

[0004] The present invention maximizes the utilization of the battery capacity by the device at low temperatures by optimizing the heating strategy. Summary of the Invention

[0005] In view of this, the present application provides a temperature control method, system, device and readable storage medium for lithium batteries to maximize the utilization of the battery capacity by the device at low temperatures.

[0006] To achieve the above object, the following solutions are proposed:

[0007] A temperature control method for a lithium battery, comprising:

[0008] During the operation of the lithium battery, when the lithium battery meets a preset heating condition, the lithium battery is heated according to a preset heating period;

[0009] After the heating process of the lithium battery is completed in the current heating period, it is monitored whether the heated lithium battery meets the heating condition. If the heated lithium battery meets the heating condition, then according to the first duty cycle corresponding to the current heating period and a preset adjustment strategy, a second duty cycle corresponding to the next heating period is determined, and it is judged whether the second duty cycle meets a preset operating condition;

[0010] If the second duty cycle meets the operating conditions, enter the next heating cycle, and continue to heat the lithium battery according to the second duty cycle until the lithium battery does not meet the heating conditions or the duty cycle corresponding to the heating cycle to be entered does not meet the operating conditions, then stop heating the lithium battery.

[0011] Optionally, the preset heating conditions are that the current battery temperature of the lithium battery is in the range of -30°C to 0°C, and the current battery capacity of the lithium battery is in the range of 30% to 60%.

[0012] Optionally, determining the second duty cycle corresponding to the next heating cycle according to the first duty cycle corresponding to the current heating cycle and a preset adjustment strategy includes:

[0013] Determine the difference between the available battery capacity increased by heating the lithium battery in the current heating cycle and the battery capacity consumed by heating.

[0014] If the difference is positive, determine the sum of the first duty cycle corresponding to the current heating cycle and the preset unit duty cycle increase value as the second duty cycle corresponding to the next heating cycle;

[0015] If the difference is negative, determine the difference between the first duty cycle corresponding to the current heating cycle and the preset unit duty cycle decrease value as the second duty cycle corresponding to the next heating cycle.

[0016] Optionally, it further includes:

[0017] In the case where the difference is positive, if the sum of the first duty cycle corresponding to the current heating cycle and the preset unit duty cycle increase value is greater than 100%, then determine the second duty cycle corresponding to the next heating cycle as 100%;

[0018] In the case where the difference is negative, if the difference between the first duty cycle corresponding to the current heating cycle and the preset unit duty cycle decrease value is less than 0%, then determine the second duty cycle corresponding to the next heating cycle as 0%.

[0019] Optionally, the heating process of the lithium battery in the current heating cycle includes:

[0020] If the current heating cycle is the first heating cycle, heat the lithium battery in the current heating cycle with a 50% duty cycle;

[0021] If the current heating cycle is not the first heating cycle, heat the lithium battery in the current heating cycle with the second duty cycle determined based on the previous heating cycle of the current heating cycle.

[0022] Optionally, the preset operating condition is that the second duty cycle is greater than 0%.

[0023] Optionally, it further includes:

[0024] During the process of heating the lithium battery, the current battery temperature and current battery capacity of the lithium battery are detected every preset time. If it is detected that the lithium battery does not meet the preset heating conditions, the heating is immediately stopped.

[0025] A lithium battery temperature control system can implement each step of a lithium battery temperature control method as described above, including a single-chip microcomputer, a Mos transistor, a DC-DC chip, a heating film, and a lithium battery with a fuel gauge;

[0026] The fuel gauge is used to obtain the battery capacity information and battery temperature information of the lithium battery and upload them to the single-chip microcomputer;

[0027] The single-chip microcomputer is connected to the fuel gauge and controls the operation of the fuel gauge through I2C;

[0028] The lithium battery is connected to the heating film, with the Mos transistor acting as a heating switch in the middle, and the DC-DC chip is used to control the heating film to heat the lithium battery;

[0029] The switching information of the Mos transistor is controlled by the duty cycle of the PWM waveform output by the single-chip microcomputer;

[0030] The heating film is used to increase the battery temperature of the lithium battery.

[0031] A lithium battery temperature control device includes a memory and a processor;

[0032] The memory is used to store programs;

[0033] The processor is used to execute the program to implement each step of a lithium battery temperature control method as described above.

[0034] A readable storage medium stores a computer program, and when the computer program is executed by a processor, each step of a lithium battery temperature control method as described above is implemented.

[0035] As can be seen from the above technical solution, in a lithium battery temperature control method, system, device, and readable storage medium provided by an embodiment of the present application, during the operation of the lithium battery, when it is monitored that the lithium battery meets a preset heating condition, the lithium battery is heated according to a preset heating period. After the heating process of the lithium battery is completed in the current heating period, it is monitored and determined whether the heated lithium battery still meets the heating condition. If it meets, the second duty cycle corresponding to the next heating period is determined according to a preset adjustment strategy. When the second duty cycle meets the preset operating condition, the lithium battery is heated in the next heating period with the second duty cycle. The heating of the lithium battery is stopped until the lithium battery does not meet the heating condition or the duty cycle corresponding to the heating period to be entered does not meet the operating condition. Therefore, the present application can determine the heating power of the next heating period that matches the current situation of the lithium battery according to the preset adjustment strategy, based on the monitored current situation of the lithium battery and the heating situation of the lithium battery in the previous round, making the heating process adjustment more accurate and maximizing the utilization of the battery capacity at low temperatures to the greatest extent.

[0036] For example, the preset adjustment strategy in the present application can be to determine the second duty cycle corresponding to the next heating period based on the difference between the available battery capacity increased by heating the lithium battery in the current heating period and the battery capacity consumed by heating. For a lithium battery with a small battery capacity, the present application can determine the duty cycle of the heating power corresponding to the next heating period by monitoring the battery temperature and battery capacity of the lithium battery after the completion of the current heating period, based on the difference between the available battery capacity increased by heating the lithium battery in the current heating period and the battery capacity consumed by heating, and the duty cycle of this heating period, that is, determine the optimal heating power corresponding to the battery temperature and battery capacity of the lithium battery after the completion of the current heating period, ensuring that the battery capacity consumed by self-heating is always less than the available battery capacity increased by the lithium battery heating, so that the self-heating process is always controlled within a beneficial range and the utilization of the battery capacity at low temperatures is maximized. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only the embodiments of the present application. For those of ordinary skill in the art, other drawings can be obtained according to the provided drawings without creative efforts.

[0038] Figure 1 It is a flowchart of a lithium battery temperature control method disclosed in the present application;

[0039] Figure 2Schematic diagram of the first example provided by the embodiments of the present application;

[0040] Figure 3 Schematic diagram of the second example provided by the embodiments of the present application;

[0041] Figure 4 Schematic structural diagram of a lithium battery temperature control system disclosed in the present application;

[0042] Figure 5 Hardware structure block diagram of a lithium battery temperature control device disclosed in the present application. Detailed implementation manners

[0043] Next, the technical solutions in the embodiments of the present application will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present application without creative efforts shall fall within the protection scope of the present application.

[0044] The embodiments of the present application provide a lithium battery temperature control method, which can be applied to various lithium battery temperature control systems to always control the self-heating process within a favorable range and maximize the utilization of the battery capacity at low temperatures.

[0045] Next, the solution of the present application will be introduced. The present application proposes the following technical solutions. For details, please refer to the following text.

[0046] Figure 1 Flowchart of a lithium battery temperature control method disclosed in the embodiments of the present application. As Figure 1 shown, the method may include:

[0047] Step S1: During the operation of the lithium battery, when the lithium battery meets the preset heating conditions, heat the lithium battery according to the preset heating period.

[0048] Specifically, during the operation of the lithium battery, if it is detected that the lithium battery meets the preset heating conditions, that is, when the current lithium battery is in a state that meets the conditions for self-heating, the lithium battery can be heated according to the preset heating period. Among them, the time of the preset heating period is generally 1 minute, but it can also be other time set in advance by humans. There is a MOS tube switch between the battery and the heating film, and the switch is controlled by the single-chip microcomputer outputting a PWM waveform, that is, the heating power of the heating film is controlled based on the duty cycle of the PWM waveform output by the single-chip microcomputer.

[0049] During the process of heating the lithium battery according to a preset heating period when the lithium battery meets the preset heating conditions, the heating frequency is determined based on the heating situation of the previous heating period of the current heating period. The preset heating period is a duration set in advance by humans, such as 1 minute, etc.

[0050] Optionally, the preset heating condition is that the current battery temperature of the lithium battery is within a preset temperature range, and the current battery capacity of the lithium battery is within a preset capacity range.

[0051] Generally, if the initial battery temperature is above 0°C, it does not belong to the low-temperature situation recognized by the lithium battery. And according to experimental tests, if the initial battery capacity is less than 30%, if self-heating is turned on and the device load is added, it will cause the battery voltage to drop too fast, thus affecting the normal use of the device. While if the initial battery capacity is greater than 60%, the remaining battery capacity is sufficient for the system to operate normally, and there is no need to turn on the self-heating function. Therefore, when the initial battery capacity is less than 30% or greater than 60%, the heating function is not turned on by default. Thus, the preset heating condition can be set as the current battery temperature of the lithium battery being within the range of -30°C to 0°C, and the current battery capacity of the lithium battery being within the range of 30% to 60%. Of course, both the preset temperature range and the preset capacity range can be adjusted manually. This application only provides an optional method obtained through tests that conforms to the actual application situation.

[0052] Further, the preset heating condition is that the current battery temperature of the lithium battery is within the range of -30°C to 0°C, and the current battery capacity of the lithium battery is within the range of 30% to 60%.

[0053] When both the current battery temperature and the current battery capacity of the lithium battery meet the above conditions, the self-heating and temperature-rising process of the lithium battery is started.

[0054] Step S2: After the heating process of the lithium battery is completed in the current heating period, monitor whether the heated lithium battery meets the heating conditions. If the heated lithium battery meets the heating conditions, determine the second duty cycle corresponding to the next heating period according to the first duty cycle corresponding to the current heating period and a preset adjustment strategy, and determine whether the second duty cycle meets the preset operating conditions.

[0055] Specifically, after the heating process of the lithium battery is completed in the current heating period, monitor whether the heated lithium battery still meets the heating conditions. If the lithium battery after heating is still in line with the heating conditions, that is, continue to heat the lithium battery in the next heating period.

[0056] In this application, the heating power of the next heating cycle will be adjusted based on the heating power of the current heating cycle according to a predetermined adjustment strategy, that is, based on the first duty cycle corresponding to the current heating cycle and the preset adjustment strategy, the second duty cycle corresponding to the next heating cycle is determined. Therefore, the heating power of each cycle is determined based on the duty cycle corresponding to its previous heating cycle according to the preset adjustment strategy.

[0057] When determining the second duty cycle corresponding to the next heating cycle, it is also necessary to determine whether the second duty cycle meets the preset operating conditions. When the second duty cycle meets the operating conditions, the second duty cycle is applied to the heating process of the next heating cycle; otherwise, the second duty cycle needs to be adjusted again.

[0058] Optionally, the preset operating condition is that the second duty cycle is greater than 0%.

[0059] It can be understood that in practical applications, when the second duty cycle, that is, the PWM duty cycle, is 0%, the corresponding heating power is 0, which means that the self-heating of the lithium battery is not turned on. Therefore, the preset operating condition should be that the second duty cycle is greater than 0%. When the second duty cycle is 0%, it is in the unheated state. The preset operating condition can be adjusted manually. This application only provides an optional method that conforms to the actual application situation.

[0060] Step S3: If the second duty cycle meets the operating conditions, enter the next heating cycle, and continue to heat the lithium battery according to the second duty cycle until the lithium battery does not meet the heating conditions or the duty cycle corresponding to the heating cycle to be entered does not meet the operating conditions, then stop heating the lithium battery.

[0061] Specifically, when the second duty cycle meets the operating conditions, the second duty cycle is applied to the next heating cycle, enter the next heating cycle, and continue to heat the lithium battery according to the second duty cycle.

[0062] After entering the next heating cycle, this next heating cycle becomes the current heating cycle. After the current heating cycle is completed, return to the process of monitoring whether the heated lithium battery meets the heating conditions. In this way, the process of "heating → monitoring whether it meets the heating conditions after heating → determining the second duty cycle according to the adjustment strategy" in steps 1 to 3 is cycled, continuously heating the lithium battery until the lithium battery does not meet the heating conditions or the duty cycle corresponding to the heating cycle to be entered does not meet the operating conditions, then stop heating the lithium battery.

[0063] In this application, the situation of stopping heating includes that the lithium battery does not meet the heating conditions, or the duty cycle corresponding to the upcoming heating cycle does not meet the operating conditions. When either of them is satisfied, the heating stops. Among them, the lithium battery not meeting the heating conditions can further include that the current battery temperature of the lithium battery is not within the range of -30°C to 0°C, or the current battery capacity of the lithium battery is not within the range of 30% to 60%. When either of them is satisfied, the lithium battery stops heating.

[0064] As can be seen from the above technical solutions, a lithium battery temperature control method, system, device, and readable storage medium provided by an embodiment of this application heat the lithium battery according to a preset heating cycle when it is monitored that the lithium battery meets the preset heating conditions during the operation of the lithium battery. After the heating process of the lithium battery is completed in the current heating cycle, it is monitored and determined whether the heated lithium battery still meets the heating conditions. If it is satisfied, the second duty cycle corresponding to the next heating cycle is determined according to the preset adjustment strategy. When the second duty cycle meets the preset operating conditions, the lithium battery is heated in the next heating cycle with the second duty cycle. The heating of the lithium battery stops until the lithium battery does not meet the heating conditions or the duty cycle corresponding to the upcoming heating cycle does not meet the operating conditions. Therefore, this application can determine the heating power of the next heating cycle that matches the current situation of the lithium battery according to the preset adjustment strategy, based on the monitored current situation of the lithium battery and the heating situation of the lithium battery in the previous cycle, making the heating process adjustment more accurate and maximizing the utilization of the battery capacity at low temperatures to the greatest extent.

[0065] For example, the preset adjustment strategy in this application can be to determine the second duty cycle corresponding to the next heating cycle according to the difference between the available battery capacity increased by heating the lithium battery in the current heating cycle and the battery capacity consumed by heating. For a lithium battery with a small battery capacity, this application can determine the duty cycle of the heating power corresponding to the next heating cycle by monitoring the battery temperature and battery capacity of the lithium battery after the current heating cycle is completed, based on the difference between the available battery capacity increased by heating the lithium battery in the current heating cycle and the battery capacity consumed by heating, and the duty cycle of this heating cycle, that is, determine the optimal heating power corresponding to the battery temperature and battery capacity of the lithium battery after the current heating cycle is completed, ensuring that the battery capacity consumed by self-heating is always less than the available battery capacity increased by the lithium battery heating up, so that the self-heating process is always controlled within a beneficial range and the utilization of the battery capacity at low temperatures is maximized.

[0066] In some embodiments of the present application, the process of determining the second duty cycle corresponding to the next heating cycle according to the first duty cycle corresponding to the current heating cycle and the preset adjustment strategy in step S2 is introduced, which may specifically include:

[0067] Step S21: Determine the difference between the available battery capacity increased by heating the lithium battery during the current heating cycle and the battery capacity consumed by heating.

[0068] Specifically, since self-heating is achieved by consuming the power of the lithium battery, a part of the battery capacity will be consumed during the self-heating process for the heating process, and heating up will liberate part of the battery capacity that cannot be used due to too low temperature. For large-capacity batteries, due to their large battery capacity, the battery capacity liberated by heating up will far exceed the part of the battery capacity consumed during the heating process. Therefore, the problem of the part of the battery capacity consumed during the heating process can be ignored for large-capacity batteries. For small-capacity batteries, their capacity is small. If the battery capacity consumed during a single heating process is greater than the available battery capacity liberated by heating up, then this heating process is not worth the loss and does not achieve a positive effect.

[0069] Considering the above situation, in the process of determining the second duty cycle corresponding to the next heating cycle according to the first duty cycle corresponding to the current heating cycle and the preset adjustment strategy, it is first necessary to determine the magnitude relationship between the available battery capacity increased by heating the lithium battery during the current heating cycle and the battery capacity consumed by heating, specifically, to determine the difference between the available battery capacity increased by heating the lithium battery during the current heating cycle and the battery capacity consumed by heating.

[0070] The method for determining the difference between the available battery capacity increased by heating the lithium battery during the current heating cycle and the battery capacity consumed by heating can be to measure the battery temperature of the current lithium battery, the heating power during the current heating cycle, that is, the magnitude of the duty cycle, and the pre-stored temperature rise table (Table 1) of the heating film corresponding to the battery temperature per unit time at different switching frequencies and the battery capacity table (Table 2) corresponding to the battery temperature obtained by pre-testing the same type of lithium battery. By looking up the table, the available battery capacity increased by heating the lithium battery during the current heating cycle and the battery capacity consumed by heating can be obtained, and the difference between the available battery capacity increased by heating the lithium battery during the current heating cycle and the battery capacity consumed by heating can be calculated.

[0071] When the difference is positive, it indicates that the battery capacity consumed during the heating process in the current heating cycle is less than the available battery capacity liberated by heating and temperature rise. The heating brings a positive effect that the user needs. In the next heating cycle, heating can continue by appropriately increasing the heating frequency. When the difference is negative, it indicates that the battery capacity consumed during the heating process in the current heating cycle is greater than the available battery capacity liberated by heating and temperature rise. The heating brings a negative effect that the user does not need. In subsequent heating cycles, the heating frequency can be continuously reduced until heating stops.

[0072]

[0073] Table 1

[0074]

[0075] Table 2

[0076] Step S22: If the difference is positive, then determine the second duty ratio corresponding to the next heating cycle as the sum of the first duty ratio corresponding to the current heating cycle and the preset unit duty ratio increment value.

[0077] Specifically, if the difference between the available battery capacity increased by heating the lithium battery in the current heating cycle and the battery capacity consumed by heating is positive, it indicates that the battery capacity consumed during the heating process in the current heating cycle is less than the available battery capacity liberated by heating and temperature rise. After heating, the lithium battery can provide more energy for the device operation than before heating. The heating brings a positive effect that the user needs. Therefore, in the next heating cycle, heating can continue by appropriately increasing the heating frequency. Specifically, the preset unit duty ratio increment value is added to the first duty ratio corresponding to the current heating cycle as the second duty ratio corresponding to the next heating cycle, that is, determine the second duty ratio corresponding to the next heating cycle as the sum of the first duty ratio corresponding to the current heating cycle and the preset unit duty ratio increment value.

[0078] For example, if the first duty ratio for heating the lithium battery in the current heating cycle is 50%, and the unit duty ratio increment value is N%, then when the difference between the available battery capacity increased by heating the lithium battery in the current heating cycle and the battery capacity consumed by heating is positive, the second duty ratio corresponding to the next heating cycle is adjusted to 50 + N%. If the difference between the available battery capacity increased by heating the lithium battery in the next heating cycle and the battery capacity consumed by heating is still positive, the duty ratio corresponding to the heating cycle after the next heating cycle is adjusted to 50 + 2N%. Here, the value of N is set manually.

[0079] Optionally, when the difference is positive, if the sum of the first duty cycle corresponding to the current heating cycle and the preset unit duty cycle increase value is greater than 100%, then determine that the second duty cycle corresponding to the next heating cycle is 100%.

[0080] In practical applications, the maximum duty cycle is 100%. After reaching 100%, it cannot be increased any further. Therefore, when the sum of the first duty cycle corresponding to the current heating cycle and the preset unit duty cycle increase value is greater than 100%, determine that the second duty cycle corresponding to the next heating cycle is the maximum duty cycle of 100%.

[0081] Step S23: If the difference is negative, then determine the difference between the first duty cycle corresponding to the current heating cycle and the preset unit duty cycle decrease value as the second duty cycle corresponding to the next heating cycle.

[0082] Specifically, if the difference between the available battery capacity increased by heating the lithium battery in the current heating cycle and the battery capacity consumed by heating is negative, it means that the battery capacity consumed during the heating process in the current heating cycle is greater than the available battery capacity liberated by heating and increasing the temperature. After heating, the lithium battery can provide less energy for the device to operate than before heating, and the heating brings a negative effect that the user does not need. Therefore, in subsequent heating cycles, the heating frequency can be continuously reduced until heating stops. Specifically, the preset unit duty cycle decrease value is subtracted from the first duty cycle corresponding to the current heating cycle as the second duty cycle corresponding to the next heating cycle, that is, determine the difference between the first duty cycle corresponding to the current heating cycle and the preset unit duty cycle decrease value as the second duty cycle corresponding to the next heating cycle.

[0083] For example, if the first duty cycle for heating the lithium battery in the current heating cycle is 50% and the unit duty cycle decrease value is N%, then when the difference between the available battery capacity increased by heating the lithium battery in the current heating cycle and the battery capacity consumed by heating is negative, the second duty cycle corresponding to the next heating cycle is adjusted to 50 - N%. If the difference between the available battery capacity increased by heating the lithium battery in the next heating cycle and the battery capacity consumed by heating is still negative, then the duty cycle corresponding to the heating cycle after the next heating cycle is adjusted to 50 - 2N%. If it is negative every time next, the duty cycle during the heating process will continue to decrease until it reaches 0%, and at this time, the self - heating of the lithium battery stops.

[0084] In this application, both the unit duty cycle increase value and the unit duty cycle decrease value are set manually, and the magnitudes of the unit duty cycle increase value and the unit duty cycle decrease value can be the same or different.

[0085] Optionally, when the difference is negative, if the difference between the first duty cycle corresponding to the current heating cycle and the preset unit duty cycle reduction value is less than 0%, it is determined that the second duty cycle corresponding to the next heating cycle is 0%.

[0086] In practical applications, the minimum duty cycle is 0%. After reaching 0%, it cannot be further reduced. At this time, the corresponding state is that the lithium battery stops heating. Therefore, when the difference between the first duty cycle corresponding to the current heating cycle and the preset unit duty cycle increase value is less than 0%, it is determined that the second duty cycle corresponding to the next heating cycle is the minimum duty cycle of 0%.

[0087] In some embodiments of the present application, the heating process of the lithium battery in the current heating cycle in step S1 is introduced, which may specifically include the following two situations:

[0088] First,

[0089] If the current heating cycle is the heating cycle of the first heating, the lithium battery is heated in the current heating cycle with a 50% duty cycle.

[0090] Specifically, in the present application, the first heating includes two situations. One is that during the normal operation of the lithium battery, for the first time, the heating condition is met, and the lithium battery needs to perform self-heating. Before this, the lithium battery has never been heated. The other is that the lithium battery has been heated before, and then stops heating due to not meeting the heating condition or the duty cycle drops to 0%. At the current moment, the heating condition is met again, and the lithium battery needs to perform self-heating.

[0091] When the current heating cycle is the heating cycle of the first heating, the lithium battery is heated in the current heating cycle with a 50% duty cycle. It can be understood that the 50% duty cycle is a preset duty cycle set by humans. In practical applications, it is not limited to 50% and can be adjusted manually.

[0092] Second,

[0093] If the current heating cycle is not the heating cycle of the first heating, the lithium battery is heated in the current heating cycle with the second duty cycle determined based on the previous heating cycle of the current heating cycle.

[0094] Specifically, if the current heating cycle is not the heating cycle of the first heating, that is, the lithium battery in the previous cycle of the current heating cycle has been in the self-heating state, then the lithium battery is heated in the current heating cycle with the second duty cycle determined based on the previous heating cycle of the current heating cycle.

[0095] For example, if the second duty cycle determined in the previous heating cycle is 50 - N%, the lithium battery is self-heated at the heating power corresponding to the duty cycle of 50 - N% in the current heating cycle.

[0096] In some embodiments of the present application, on the basis of the above embodiments, it may further include:

[0097] Step S4: During the process of heating the lithium battery, the current battery temperature and the current battery capacity of the lithium battery are detected every preset time. If it is detected that the lithium battery does not meet the preset heating conditions, the heating is immediately stopped.

[0098] Specifically, in order to save power to the greatest extent in the present application, during the process of heating the lithium battery, the current battery temperature and the current battery capacity of the lithium battery are detected every preset time. If it is detected that the lithium battery does not meet the preset heating conditions, the heating is immediately stopped. If the preset heating conditions are always met, the heating work of the current heating cycle is continuously completed.

[0099] For example, the artificially set heating cycle is 1 minute. During the self-heating process of the lithium battery at the heating power corresponding to a duty cycle of 50 - N% in the current heating cycle, if it is detected whether the lithium battery meets the preset heating conditions every 10 seconds, at the 10th second, it is detected for the first time whether the current lithium battery meets the preset heating conditions. If it is met, the heating continues, and it is detected again at the 20th second. If it is found at the 20th second that the current lithium battery no longer meets the preset heating conditions, the self-heating of the lithium battery is immediately stopped at the 20th second. It can be understood that if the lithium battery meets the preset heating conditions every time it is detected within this one minute, the heating work of the current heating cycle will be successfully completed and the next heating cycle will be entered.

[0100] The following combines Figure 2 and Figure 3 to illustrate the present application with two specific examples respectively. In this example, the set heating cycle is 1 minute. During the process of heating the lithium battery, the detection interval preset time is 10 seconds, the unit duty cycle increase value is 30, the unit duty cycle decrease value is also 30, and the lithium battery has never been self-heated before.

[0101] First,

[0102] As Figure 2 shown, when it is detected that the lithium battery meets the heating conditions, it enters the first heating cycle. In the first heating cycle, the lithium battery is heated at a 50% duty cycle in the first heating cycle, and it is detected every 10 seconds in the first heating cycle whether the lithium battery still meets the preset heating conditions.

[0103] If the lithium battery always meets the heating conditions during the first heating cycle, after completing the heating work of the first heating cycle for 1 minute, according to the duty cycle corresponding to the first heating cycle and the preset adjustment strategy, determine the duty cycle corresponding to the second heating cycle, and enter the second heating cycle. In this example, since the difference is positive, the duty cycle corresponding to the second heating cycle is 80%. The duty cycle of 80% meets the preset operating conditions, and enters the second heating cycle.

[0104] After entering the second heating cycle, since the duty cycle of 80% does not exceed the maximum duty cycle of 100%, the lithium battery self-heats at the heating power corresponding to the duty cycle of 80% during the second heating cycle. And during the second heating cycle, the lithium battery is detected every 10 seconds to see if it still meets the preset heating conditions.

[0105] If the lithium battery always meets the heating conditions during the second heating cycle, after completing the heating work of the second heating cycle for 1 minute, according to the duty cycle corresponding to the second heating cycle and the preset adjustment strategy, determine the duty cycle corresponding to the third heating cycle, and enter the third heating cycle. In this example, since the difference is still positive during the second heating cycle, the duty cycle corresponding to the third heating cycle is 110%. The duty cycle of 110% meets the preset operating conditions, and enters the third heating cycle.

[0106] After entering the third heating cycle, since the duty cycle of 110% exceeds the maximum duty cycle of 100%, the lithium battery self-heats at the heating power corresponding to the maximum duty cycle of 100% during the third heating cycle. And during the third heating cycle, the lithium battery is detected every 10 seconds to see if it still meets the preset heating conditions.

[0107] If it is detected that the lithium battery does not meet the preset heating conditions at the 30th second of the third heating cycle, stop heating at the 30th second of the third heating cycle.

[0108] Second,

[0109] As Figure 3 shown, when it is detected that the lithium battery meets the heating conditions, enter the first heating cycle. During the first heating cycle, the lithium battery heats the lithium battery at a duty cycle of 50% during the first heating cycle, and during the first heating cycle, the lithium battery is detected every 10 seconds to see if it still meets the preset heating conditions.

[0110] If the lithium battery always meets the heating conditions during the first heating cycle, after completing the heating work of the first heating cycle for 1 minute, according to the duty cycle corresponding to the first heating cycle and the preset adjustment strategy, determine the duty cycle corresponding to the second heating cycle, and enter the second heating cycle. Specifically, determine the next heating cycle based on the difference between the available battery capacity increased by heating the lithium battery and the battery capacity consumed by heating during the first heating cycle. In this example, since the difference is negative, the duty cycle corresponding to the second heating cycle is 20%. The duty cycle of 20% meets the preset operating conditions, and enter the second heating cycle.

[0111] After entering the second heating cycle, the lithium battery self-heats at the heating power corresponding to a duty cycle of 20%. And in the second heating cycle, detect whether the lithium battery still meets the preset heating conditions every 10 seconds.

[0112] If the lithium battery always meets the heating conditions during the second heating cycle, after completing the heating work of the second heating cycle for 1 minute, according to the duty cycle corresponding to the second heating cycle and the preset adjustment strategy, determine the duty cycle corresponding to the third heating cycle. In this example, since the difference is still negative during the second heating cycle, the duty cycle corresponding to the second heating cycle is -10%. The duty cycle of -10% does not meet the preset operating conditions, and at this time, stop heating.

[0113] Next, a lithium battery temperature control system provided by an embodiment of the present application will be described. The lithium battery temperature control system described below can be correspondingly referred to the lithium battery temperature control method described above, and can implement each step of a lithium battery temperature control method as described in any one of the above.

[0114] See Figure 4 , Figure 4 which is a schematic structural diagram of a lithium battery temperature control system disclosed in an embodiment of the present application.

[0115] As Figure 4 shown, the system may include a single-chip microcomputer, a Mos tube, a DC-DC chip, a heating film, and a lithium battery with a fuel gauge.

[0116] The fuel gauge is used to obtain the battery capacity information and battery temperature information of the lithium battery, and upload them to the single-chip microcomputer;

[0117] The single-chip microcomputer is connected to the fuel gauge and controls the operation of the fuel gauge through I2C;

[0118] The lithium battery is connected to the heating film, with the Mos tube as the heating switch in the middle, and the DC-DC chip is used to control the heating film to heat the lithium battery;

[0119] The switching information of the MOS transistor is controlled by the duty cycle of the PWM waveform output by the single-chip microcomputer;

[0120] The heating film is used to increase the battery temperature of the lithium battery.

[0121] As can be seen from the above technical solutions, a lithium battery temperature control system provided by an embodiment of the present application, during the operation of the lithium battery, when it is monitored that the lithium battery meets the preset heating conditions, the lithium battery will be heated according to a preset heating cycle. And after the heating process of the lithium battery is completed in the current heating cycle, it is monitored and determined whether the heated lithium battery still meets the heating conditions. If it meets, the second duty cycle corresponding to the next heating cycle is determined according to a preset adjustment strategy. When the second duty cycle meets the preset operating conditions, the lithium battery is heated in the next heating cycle with the second duty cycle. Until the lithium battery does not meet the heating conditions or the duty cycle corresponding to the heating cycle to be entered does not meet the operating conditions, the heating of the lithium battery is stopped. Therefore, the present application can determine the heating power of the next heating cycle that matches the current situation of the lithium battery according to the preset adjustment strategy, based on the monitored current situation of the lithium battery and the heating situation of the lithium battery in the previous cycle, making the heating process adjustment more accurate and maximizing the utilization of the battery capacity at low temperatures to the greatest extent.

[0122] For example, the preset adjustment strategy in the present application can be to determine the second duty cycle corresponding to the next heating cycle according to the difference between the available battery capacity increased by heating the lithium battery in the current heating cycle and the battery capacity consumed by heating. For a lithium battery with a small battery capacity, the present application can determine the duty cycle of the heating power corresponding to the next heating cycle by monitoring the battery temperature and battery capacity of the lithium battery after the completion of the current heating cycle, based on the difference between the available battery capacity increased by heating the lithium battery in the current heating cycle and the battery capacity consumed by heating, and the duty cycle of this heating cycle, that is, determine the optimal heating power corresponding to the battery temperature and battery capacity of the lithium battery after the completion of the current heating cycle, ensuring that the battery capacity consumed by self-heating is always less than the available battery capacity increased by heating the lithium battery, so that the self-heating process is always controlled within a beneficial range and the utilization of the battery capacity at low temperatures is maximized.

[0123] A lithium battery temperature control system provided by an embodiment of the present application can be applied to a lithium battery temperature control device. Optionally, Figure 5 shows a hardware structure block diagram of a lithium battery temperature control device. Refer to Figure 5 A hardware structure of a lithium battery temperature control device may include: at least one processor 1, at least one communication interface 2, at least one memory 3, and at least one communication bus 4;

[0124] In the embodiments of the present application, the number of the processor 1, the communication interface 2, the memory 3, and the communication bus 4 is at least one, and the processor 1, the communication interface 2, and the memory 3 complete mutual communication through the communication bus 4;

[0125] The processor 1 may be a central processing unit (CPU), or a specific integrated circuit (ASIC) (Application Specific Integrated Circuit), or one or more integrated circuits configured to implement the embodiments of the present invention, etc.;

[0126] The memory 3 may include a high-speed RAM memory, and may also include a non-volatile memory, such as at least one disk memory;

[0127] Wherein, the memory stores a program, and the processor can call the program stored in the memory, and the program is used for:

[0128] During the operation of the lithium battery, when the lithium battery meets the preset heating condition, heat the lithium battery according to the preset heating period;

[0129] After the heating process of the lithium battery is completed in the current heating period, monitor whether the heated lithium battery meets the heating condition. If the heated lithium battery meets the heating condition, determine the second duty cycle corresponding to the next heating period according to the first duty cycle corresponding to the current heating period and the preset adjustment strategy, and judge whether the second duty cycle meets the preset operating condition;

[0130] If the second duty cycle meets the operating condition, enter the next heating period, and continue to heat the lithium battery according to the second duty cycle until the lithium battery does not meet the heating condition or the duty cycle corresponding to the heating period to be entered does not meet the operating condition, then stop heating the lithium battery.

[0131] Optionally, the refined functions and extended functions of the program can be referred to the above description.

[0132] The embodiments of the present application also provide a readable storage medium, which can store a program suitable for the processor to execute, and the program is used for:

[0133] During the operation of the lithium battery, when the lithium battery meets the preset heating condition, heat the lithium battery according to the preset heating period;

[0134] After completing the heating process of the lithium battery in the current heating cycle, monitor whether the heated lithium battery meets the heating condition. If the heated lithium battery meets the heating condition, determine the second duty cycle corresponding to the next heating cycle according to the first duty cycle corresponding to the current heating cycle and a preset adjustment strategy, and determine whether the second duty cycle meets the preset operating condition;

[0135] If the second duty cycle meets the operating condition, enter the next heating cycle, and continue to heat the lithium battery according to the second duty cycle until the lithium battery does not meet the heating condition or the duty cycle corresponding to the heating cycle to be entered does not meet the operating condition, then stop heating the lithium battery.

[0136] Optionally, the refinement functions and expansion functions of the program can be referred to the above description.

[0137] Finally, it should be noted that in this article, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variant thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements not only includes those elements, but also includes other elements not expressly listed, or also includes elements inherent to such process, method, article or device. Without further limitation, an element defined by the statement "including a..." does not exclude the existence of additional identical elements in the process, method, article or device including the element.

[0138] The various embodiments in this specification are described in a progressive manner. Each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0139] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present application. Various modifications to these embodiments will be apparent to those skilled in the art. The general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A temperature control method for a lithium battery, characterized in that, Including: During the operation of the lithium battery, when the lithium battery meets the preset heating conditions, heat the lithium battery according to a preset heating period. After the heating process of the lithium battery is completed in the current heating period, monitor whether the heated lithium battery meets the heating conditions. If the heated lithium battery meets the heating conditions, determine the second duty cycle corresponding to the next heating period according to the first duty cycle corresponding to the current heating period and a preset adjustment strategy, and judge whether the second duty cycle meets the preset operating conditions. If the second duty cycle meets the operating conditions, enter the next heating period, and continue to heat the lithium battery according to the second duty cycle until the lithium battery does not meet the heating conditions or the duty cycle corresponding to the heating period to be entered does not meet the operating conditions, then stop heating the lithium battery. Determining the second duty cycle corresponding to the next heating period according to the first duty cycle corresponding to the current heating period and a preset adjustment strategy includes: Determine the difference between the available battery capacity increased by heating the lithium battery in the current heating period and the battery capacity consumed by heating. If the difference is positive, determine the sum of the first duty cycle corresponding to the current heating period and the preset unit duty cycle increase value as the second duty cycle corresponding to the next heating period. If the difference is negative, determine the difference between the first duty cycle corresponding to the current heating period and the preset unit duty cycle decrease value as the second duty cycle corresponding to the next heating period.

2. The method according to claim 1, characterized in that, The preset heating conditions are that the current battery temperature of the lithium battery is in the range of -30°C to 0°C, and the current battery capacity of the lithium battery is in the range of 30% to 60%.

3. The method according to claim 1, characterized in that Also including: In the case where the difference is positive, if the sum of the first duty cycle corresponding to the current heating period and the preset unit duty cycle increase value is greater than 100%, determine the second duty cycle corresponding to the next heating period as 100%. In the case where the difference is negative, if the difference between the first duty cycle corresponding to the current heating period and the preset unit duty cycle decrease value is less than 0%, determine the second duty cycle corresponding to the next heating period as 0%.

4. The method according to claim 1, characterized in that, The heating process of the lithium battery in the current heating period includes: If the current heating period is the first heating period, heat the lithium battery in the current heating period with a 50% duty cycle. If the current heating period is not the first heating period, heat the lithium battery in the current heating period with the second duty cycle determined based on the previous heating period of the current heating period.

5. The method according to claim 1, wherein The preset operating condition is that the second duty cycle is greater than 0%.

6. The method according to any one of claims 1-5, characterized in that, Also including: During the heating process of the lithium battery, detect the current battery temperature and current battery capacity of the lithium battery every preset time. If it is detected that the lithium battery does not meet the preset heating conditions, stop heating immediately.

7. A lithium battery temperature control system, characterized in that, It can implement each step of a lithium battery temperature control method described in any one of the above claims 1-6, including a single-chip microcomputer, a Mos transistor, a DC-DC chip, a heating film, and a lithium battery with a fuel gauge; The fuel gauge is used to obtain the battery capacity information and battery temperature information of the lithium battery and upload them to the single-chip microcomputer; The single-chip microcomputer is connected to the fuel gauge and controls the operation of the fuel gauge through I2C; The lithium battery is connected to the heating film, with the Mos transistor acting as a heating switch in the middle, and the DC-DC chip is used to control the heating film to heat the lithium battery; The switching information of the Mos transistor is controlled by the duty cycle of the PWM waveform output by the single-chip microcomputer; The heating film is used to increase the battery temperature of the lithium battery.

8. A lithium battery temperature control device, characterized in that, It includes a memory and a processor; The memory is used to store programs; The processor is used to execute the program to implement each step of a lithium battery temperature control method described in any one of claims 1-6.

9. A readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it implements each step of a lithium battery temperature control method described in any one of claims 1-6.

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