A heating control method and system for battery coolant

Abstract

The present invention provides a battery coolant heating control method and system, comprising: detecting the current battery temperature T; determining whether heating is required using a heating device and whether heat transfer by coolant is required based on the temperature range of the current battery temperature T; if heating is required using a heating device, controlling the heating device to be in an operative state; and if heat transfer by coolant is required, controlling the coolant drive device to be in an operative state. The present invention considers the impact of battery self-heating on the battery temperature rise rate and incorporates changes in battery self-heating into the battery coolant temperature control strategy. This balances charging efficiency and power consumption, enabling battery charging to be completed with the highest cost-effectiveness, thereby extending the battery's service life.

Description

Technical Field

[0001] The present invention relates to the field of power batteries, and in particular to a heating control method and system for battery coolant. Background Art

[0002] When charging a battery, improper temperatures can affect charging efficiency. More specifically, due to inherent limitations, batteries can only achieve the required charge rate range within the appropriate temperature range. The charge rate directly determines the battery's charging speed. When batteries leave the factory, engineers predetermine the charge rate ranges achievable by the battery at different temperature ranges and then configure a charge rate change strategy for different scenarios. Generally speaking, this charge rate change strategy is related to the battery voltage, remaining charge, and current battery temperature.

[0003] In the related art, when a battery is at a low temperature, the battery coolant is typically heated at a fixed power and allowed to flow around the battery. This heat conduction raises the battery temperature, keeping it within an appropriate temperature range. The charge rate is then adjusted in real time according to a pre-set battery charge rate change strategy to complete charging. However, the inventors of this case discovered that the temperature rise of the power battery during low-temperature charging is not only due to heat conduction from the coolant, but also from self-heating generated by chemical changes within the battery during charging. Furthermore, the amount of self-heating generated by the battery varies with the battery's temperature range and its charge rate. Therefore, the aforementioned control strategy of heating the coolant at a fixed power actually wastes resources. Summary of the Invention

[0004] In view of this, an object of the present invention is to provide a heating control method and system for battery coolant.

[0005] The present invention provides a method for controlling heating of a battery coolant, comprising the following steps:

[0006] Detect the current battery temperature T;

[0007] Determine whether heating by a heating device is required and whether heat transfer by coolant is required based on the temperature range of the current battery temperature T;

[0008] If heating is required using a heating device, the heating device is controlled to be in working state;

[0009] If it is necessary to use the coolant to transfer heat, the coolant drive device is controlled to be in a working state.

[0010] Optionally, the step of determining whether heating by a heating device is required and whether heat transfer by a coolant is required according to the temperature range in which the current battery temperature T is located includes:

[0011] If the current battery temperature T is lower than the first set temperature T1, it is determined that heating is required by the heating device, the coolant driving device is controlled to operate, the coolant driving device is used to drive the coolant circulation, and the heating device is controlled to operate, the coolant is heated by the heating device;

[0012] If the current battery temperature T is greater than or equal to the first set temperature T1 and less than or equal to the second set temperature T2, it is determined that heating by the heating device is not required, but heat equalization by the coolant is required, and the heating device is controlled to be in a non-operating state, while the coolant drive device is controlled to be in an operating state;

[0013] If the current battery temperature T is greater than the second set temperature T2, it is determined that heating by the heating device is not necessary, and the heating device is controlled to be in a non-operating state.

[0014] Optionally, the step of heating the coolant by using a heating device includes:

[0015] When the heating device starts working, the timing starts, the current battery temperature T is detected at a set time interval t, and the battery temperature rise rate is determined based on the battery temperature difference between the two detections. The target temperature of the coolant is updated based on the battery temperature rise rate. The target temperature of the coolant is affected by the change in the target temperature of the coolant until the battery temperature rise rate is maintained within the required range.

[0016] If the battery temperature rise rate is less than the first rate, the preset coolant target temperature is used as the updated coolant target temperature at the end of the first measurement. At the end of each subsequent measurement, Treq n =Treq n-1 +d, where Treq is the updated coolant target temperature, d is the set incremental value, and n is the number of measurements;

[0017] If the battery temperature rise rate is greater than the second rate, the target coolant temperature set when the heating device starts working is used as the updated target coolant temperature at the end of the first measurement. At the end of each subsequent measurement, Treq n =Treq n-1 -d;

[0018] If the battery temperature rise rate is between the first rate and the second rate, the coolant target temperature updated a set time interval ago is maintained unchanged.

[0019] Optionally, the step of determining whether heating by a heating device is required and whether heat transfer by a coolant is required according to the temperature range in which the current battery temperature T is located includes:

[0020] If the current battery temperature T is lower than the first set temperature T1, it is determined that the coolant needs to be used for heat transfer, and the coolant drive device is controlled to be in the working state;

[0021] If the current battery temperature T is greater than or equal to the first set temperature T1 and less than or equal to the second set temperature T2, it is determined that heating by the heating device is not required, but heat equalization by the coolant is required, and the heating device is controlled to be in a non-operating state, while the coolant drive device is controlled to be in an operating state;

[0022] If the current battery temperature T is greater than the second set temperature T2, it is determined that heating by the heating device is not necessary, and the heating device is controlled to be in a non-operating state.

[0023] Optionally, if the current battery temperature T is lower than the first set temperature T1, after determining that the coolant needs to be used for heat transfer and controlling the coolant drive device to be in a working state, the method further includes:

[0024] Further determine whether heating is required using a heating device.

[0025] Optionally, the step of further determining whether heating by a heating device is required includes:

[0026] Determining whether the battery temperature is lower than a third set temperature T3;

[0027] If the battery temperature is lower than the third set temperature T3, it is determined that the heating device needs to be controlled to heat the coolant;

[0028] If the battery temperature is greater than the third set temperature T3, the current battery charging rate a is further detected, and according to the relationship between the current battery charging rate a and the set charging rate A, it is determined whether the heating device needs to be operated.

[0029] Optionally, the step of determining whether the heating device needs to be operated based on the relationship between the current battery charging rate a and the set charging rate A includes:

[0030] If the battery charging rate a is greater than the set charging rate A, it is determined that the heating device does not need to be operated;

[0031] If the charging rate a of the battery is less than or equal to the set charging rate A, the heating device is put into operation and controlled to heat the coolant.

[0032] Optionally, the step of heating the coolant by using a heating device includes:

[0033] The timing starts when the heating device starts working, and the current battery temperature T is detected at a set time interval t. The battery temperature rise rate is determined based on the battery temperature difference between the two previous and subsequent detections. An appropriate rule is selected based on the battery temperature rise rate to update the coolant target temperature. The battery temperature rise rate is affected by the change in the coolant target temperature until the battery temperature rise rate is maintained within the required range.

[0034] Optionally, the step of selecting an appropriate rule to update the target temperature of the coolant according to the battery temperature rise rate, and affecting the battery temperature rise rate by changing the target coolant temperature until the battery temperature rise rate is maintained within a desired range includes:

[0035] If the battery temperature rise rate is less than the first rate, then at the end of the first measurement, the preset coolant target temperature is used as the updated coolant target temperature. At the end of each subsequent measurement, Treq n =Treq n-1 +d, where Treq is the updated coolant target temperature, d is the set progressive value, and n is the number of measurements. When the battery temperature is less than the third set temperature T3 and the coolant is heated by the heating device, the preset coolant target temperature is the first target temperature t1. When the battery charge rate a is less than or equal to the set charge rate A and the coolant is heated by the heating device, the preset coolant target temperature is the second target temperature t2. The calculation formula for the second target temperature t2 is: t2 = t1 - a × b + c, where b is the charge rate compensation value and c is the battery temperature compensation value.

[0036] If the battery temperature rise rate is greater than the second rate, at the end of the first measurement, the preset coolant target temperature is used as the updated coolant target temperature. At the end of each subsequent measurement, Treq n =Treq n-1 -d;

[0037] If the battery temperature rise rate is between the first rate and the second rate, the coolant target temperature updated a set time interval ago is maintained unchanged.

[0038] The present invention also provides a battery coolant heating control system, comprising:

[0039] Detection module, used to detect the current battery temperature T;

[0040] A control module is used to execute the heating control method described in any one of the above schemes.

[0041] In summary, the present invention takes into account the impact of battery self-heating on the battery temperature rise rate, incorporates the changes in battery self-heating into the battery coolant temperature rise control strategy, takes into account both charging efficiency and power consumption, and enables the battery to be charged with the highest cost-effectiveness, thereby extending the battery life.

[0042] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present invention more obvious and easy to understand, the following preferred embodiments are specifically cited and described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 This is a flowchart of embodiment 1 of the present invention.

[0044] Figure 2 This is a flowchart of the second embodiment of the present invention. DETAILED DESCRIPTION

[0045] The following embodiments of the present invention are described in further detail with reference to the accompanying drawings and examples. The following examples are used to illustrate the present invention but are not intended to limit the scope of the present invention.

[0046] The terms "first", "second" and the like in the description and claims of the present invention are used to distinguish similar objects and are not necessarily used to describe a particular sequence or order.

[0047] The present invention provides a heating control method for battery coolant, which is particularly suitable for scenarios where the battery is fast charged at low temperatures. The method considers the impact of self-heating generated by batteries in different temperature ranges at different charging rates during the charging process on the battery temperature rise, and accordingly controls the coolant driving device to drive the coolant to flow around the battery and / or controls the heating device to heat the coolant, so as to achieve both reduced energy consumption and shortened fast charging time, and ensure that the temperature rise rate of the battery can be controlled within a certain range when fast charging is performed regardless of the residual charge state, thereby maintaining battery safety.

[0048] Example 1

[0049] like Figure 1 As shown, the battery coolant heating control method provided in this embodiment includes the following steps:

[0050] S10: Detect the current battery temperature T; it should be noted that the current battery temperature T mentioned here can be either the average temperature of the battery pack in the power battery system or the lowest temperature of each battery module in the power battery system. The current battery temperature T mentioned in this embodiment is the lowest temperature of each battery module in the power battery system.

[0051] S20: Determine whether heating by a heating device is required and whether heat transfer by coolant is required based on the temperature range of the current battery temperature T. If heating by a heating device is required, control the heating device to be in an operating state. If heat transfer by coolant is required, control the coolant drive device to be in an operating state.

[0052] Specifically, in step S20:

[0053] If the relationship between the current battery temperature T and the first set temperature T1 (preferably 10-15°C) is T<T1, it is determined that heating is required by the heating device and heat transfer is required by the coolant. The coolant driving device and the heating device are controlled to be in the working state at the same time to heat the battery with the coolant. At this time, the target temperature of the coolant can be flexibly set as needed;

[0054] If the relationship between the current battery temperature T and the first set temperature T1 (preferably 10-15°C) and the second set temperature T2 (preferably 15-20°C) is T1≤T≤T2, it is determined that heating by the heating device is not necessary, but heat transfer by the coolant is required; since the battery temperature can be gradually increased by relying solely on the self-heating of the battery during charging, the battery can be charged with the highest cost-effectiveness (charging efficiency and power consumption). Therefore, in this case, the heating device is in a non-operating state. In addition, in order to ensure uniform temperature between the various battery modules and create a charging environment that is conducive to the life of the power battery, the coolant drive device should be in an operating state so that the coolant flows around the battery to balance the temperature between the various battery modules;

[0055] If the relationship between the current battery temperature T and the second set temperature T2 is T>T2, then it is determined that heating by the heating device is not necessary, and the heating device is placed in a non-operating state. In addition, since the battery temperature itself is relatively high in this environment, the self-heating generated during the charging process can already complete the entire charging process with high efficiency. Therefore, regardless of whether the coolant drive device is in an operating state, the battery can complete charging with the highest cost-effectiveness. From the perspective of completing charging with the highest cost-effectiveness, the coolant drive device can be placed in an operating state or in a non-operating state. In the entire power battery management strategy, whether it is necessary to use the coolant to transfer heat to put the coolant drive device in an operating state at this time requires separate judgment, such as whether temperature equalization or cooling is required. The specific judgment strategy is a prior art unrelated to the present invention and will not be described in detail here.

[0056] Furthermore, in step S20, when heating by the heating device, in order to control the temperature rise rate of the battery within a certain range during the entire charging process, the following control steps may also be performed simultaneously:

[0057] Step S60: Start timing when the heating device is turned on, detect the current battery temperature T at a set time interval t (for example, 0.5 minutes), and combine the difference in battery temperature obtained from the two previous and subsequent detections to determine the battery temperature rise rate v (the calculation formula for the battery temperature rise rate is Where T t Indicates the battery temperature at time t, T t0 represents the battery temperature before the set time interval), and then selects an appropriate rule to update the coolant target temperature according to the battery temperature rise rate v. The battery temperature rise rate is affected by the change of the coolant target temperature until the battery temperature rise rate is maintained within the required range.

[0058] It should be noted that the heating device can change its power according to the target temperature of the coolant. In this way, when the battery temperature rise rate is large, the battery temperature rise rate can be reduced by reducing the coolant temperature change within the set time interval. When the battery temperature rise rate is small, the battery temperature rise rate can be increased by increasing the coolant temperature change within the set time interval. In this way, by controlling the range of change of the output power of the heating device, the battery temperature rise rate can be controlled within the required range after the coolant target temperature is updated 2 to 5 times.

[0059] Based on this, a more specific description of step S60 includes the following:

[0060] If the battery temperature rise rate v is less than the first rate V1 (preferably 0.5-0.6°C / min for ternary batteries and 0.7-0.8°C / min for iron-lithium batteries), the process proceeds to step S601 to update the target temperature of the coolant using the following rules:

[0061] At the end of the first measurement, take Treq1 = Treq0; for the second measurement and thereafter, take Treq n =Treq n-1 +d.

[0062] Where Treq is the updated coolant target temperature, T req0 The target coolant temperature is set to the target temperature at the start of the heating device operation. d is the set increment value (preferably 5°C), and n is the number of measurements. It should be noted that Treq1 = Treq0 at the end of the first measurement because the heating device requires a certain time interval after being turned on to achieve a certain operating efficiency. Setting the target coolant temperature after the first measurement as the target coolant temperature set at the start of the heating device operation can compensate for the time it takes for the heating device to reach a certain operating efficiency after being turned on.

[0063] If the battery temperature rise rate is greater than the second rate (preferably 0.6-0.7°C / min for ternary batteries and 0.8-0.9°C / min for iron-lithium batteries), the process proceeds to step S602 to update the target temperature of the coolant heated by the heating device using the following rules:

[0064] At the end of the first measurement, take Treq1 = Treq0, and for the second measurement and thereafter, take Treq n =Treq n-1 -d.

[0065] If the battery temperature rise rate is between the first rate and the second rate, the process proceeds to step S603 to maintain the target coolant temperature updated a set time interval ago.

[0066] Example 2

[0067] like Figure 2 As shown, the battery coolant heating control method of this embodiment includes:

[0068] S10: Detect the current battery temperature T;

[0069] S20: Determine whether heating by a heating device is required and whether heat transfer by coolant is required based on the temperature range of the current battery temperature T. If heating by a heating device is required, control the heating device to be in an operating state. If heat transfer by coolant is required, control the coolant drive device to be in an operating state.

[0070] Specifically, in step S20, the control method when the current battery temperature is greater than the second set temperature T2, and when the current battery temperature is greater than or equal to the first set temperature T1 (preferably 10-15°C) and less than or equal to the second set temperature T2, is the same as in the first embodiment and will not be repeated here. The difference between step S20 of this embodiment and the first embodiment lies in the control method when the current battery temperature is less than the first set temperature T1.

[0071] In this embodiment, if the current battery temperature T is lower than the first set temperature T1, it is determined that the coolant needs to be used for heat transfer to put the coolant drive device into working state, and it is further determined whether the battery temperature is lower than the third set temperature T3 (preferably -5 to 10°C). If the battery temperature is lower than the third set temperature T3, it is determined that the heating device needs to be controlled to work and the process goes to step S41; otherwise, the process goes to step S42.

[0072] Step S41: Controlling the operation of the heating device and setting the target temperature of the coolant heated by the heating device to a first target temperature t1 (preferably 30°C). Then, the heating device is controlled to operate at a higher output power according to the control method of step S60 to heat the battery more quickly.

[0073] Step S42: further detect the current battery charging rate a, and determine whether the heating device needs to be operated based on the relationship between the current battery charging rate a and the set charging rate A. If the battery charging rate is above the set charging rate A (the preferred value for the ternary battery is between 0.7 and 1.0C, and the preferred value for the iron-lithium battery is between 0.9 and 1.2C), it means that the battery charging rate in this scenario is relatively large, and the battery's own heat temperature rise can meet the battery's temperature rise rate requirement. At this time, the heating device is controlled to be in a non-working state.

[0074] On the contrary, if the charging rate of the battery is less than or equal to the set charging rate A, it is determined that the heating device needs to be activated, and the process proceeds to step S421 to further determine the target temperature of the coolant.

[0075] Step S421: The heating device is put into operation, and the target temperature of the coolant is set to a second target temperature t2. The calculation formula of the second target temperature t2 is:

[0076] t2=t1-a×b+c.

[0077] Wherein, b is the charge rate compensation value, which increases with the current battery charge rate, and c is the battery temperature compensation value, which increases with the current battery temperature T. The values ​​of the charge rate compensation value b and the battery temperature compensation value c can be adjusted as needed. Preferably, the charge rate compensation value is within 3 to 8. For example, when the current battery charge rate is within 0.1 to 0.3C, the charge rate compensation value is 3. When the current battery charge rate is within 0.3 to 0.5C, the charge rate compensation value is 5. When the current battery charge rate is within 0.5 to 0.7C, the charge rate compensation value takes the maximum value of 8.

[0078] Preferably, the battery temperature compensation value is within the range of 0 to 20. For example, if the current battery temperature T is -5°C ≤ T < 0°C, the battery temperature compensation value is 5; if the current battery temperature T is 0°C ≤ T < 5°C, the battery temperature compensation value is 10; if the current battery temperature T is 5°C ≤ T < 10°C, the battery temperature compensation value is 15; if the current battery temperature T is 10°C ≤ T < 15°C, the battery temperature compensation value is 20.

[0079] Correspondingly, after the target temperature of the coolant is set in step S421, the heating device can be controlled to perform heating according to the control method of step S60.

[0080] In summary of the above two embodiments, the battery coolant heating control method provided by the present invention introduces the temperature increase factor caused by battery self-heating into the battery heating strategy, so that the battery can be charged with a high cost-effectiveness (charging efficiency and power consumption).

[0081] Based on these two embodiments, the present invention further provides a battery coolant heating control system, comprising:

[0082] Detection module, used to detect the current battery temperature T;

[0083] The control module is used to determine whether heating by a heating device is required and whether coolant is required to transfer heat based on the current battery temperature T. When heating by a heating device is required, the control module controls the heating device to be in an operating state; when heat transfer by coolant is required, the control module controls the coolant drive device to be in an operating state.

[0084] Specifically, when the current battery temperature T is lower than the first set temperature T1, the control module determines that the coolant needs to be used for heat transfer, and controls the coolant drive device to be in a working state; when the current battery temperature T is greater than or equal to the first set temperature T1 and less than or equal to the second set temperature T2, the control module determines that the heating device is not needed for heating, but the coolant needs to be used for heat transfer, controls the heating device to be in a non-working state, and controls the coolant drive device to be in a working state at the same time; when the current battery temperature T is higher than the second set temperature T2, determines that the heating device is not needed for heating, and controls the heating device to be in a non-working state.

[0085] In summary, the present invention takes into account the impact of battery self-heating on the battery temperature rise rate, incorporates the changes in battery self-heating into the battery coolant temperature rise control strategy, takes into account both charging efficiency and power consumption, and can control the charging rate to always fall within a certain range during the charging process, so that the battery can be charged with the highest cost-effectiveness and extend the battery life.

[0086] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any modifications or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in the present invention should be included in the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be based on the scope of protection of the claims.

Claims

1. A method for controlling heating of a battery coolant, characterized in that: The steps include: Detect the current battery temperature T; Determine whether heating by a heating device is required and whether heat transfer by coolant is required based on the temperature range of the current battery temperature T; If heating is required using a heating device, the heating device is controlled to be in working state; If it is necessary to use coolant to transfer heat, the coolant drive device is controlled to be in working state; The steps of determining whether heating by a heating device is required and whether heat transfer by a coolant is required according to the temperature range in which the current battery temperature T is located include: If the current battery temperature T is lower than the first set temperature T1, it is determined that heating is required by the heating device, the coolant driving device is controlled to operate, the coolant driving device is used to drive the coolant circulation, and the heating device is controlled to operate, the coolant is heated by the heating device; If the current battery temperature T is greater than or equal to the first set temperature T1 and less than or equal to the second set temperature T2, it is determined that heating by the heating device is not required, but heat equalization by the coolant is required, and the heating device is controlled to be in a non-operating state, while the coolant drive device is controlled to be in an operating state; If the current battery temperature T is greater than the second set temperature T2, it is determined that heating by the heating device is not necessary, and the heating device is controlled to be in a non-operating state; The steps of heating the coolant using the heating device include: The timing starts when the heating device starts working, and the current battery temperature T is detected at a set time interval t. The battery temperature rise rate is determined based on the battery temperature difference between the two detections. An appropriate rule is selected based on the battery temperature rise rate to update the coolant target temperature. The battery temperature rise rate is affected by the change in the coolant target temperature until the battery temperature rise rate is maintained within the desired range. If the battery temperature rise rate is less than the first rate, the preset coolant target temperature is used as the updated coolant target temperature at the end of the first measurement. At the end of each subsequent measurement, Treq n =Treq n-1 +d, where Treq is the updated coolant target temperature, d is the set incremental value, and n is the number of measurements; If the battery temperature rise rate is greater than the second rate, the target coolant temperature set when the heating device starts working is used as the updated target coolant temperature at the end of the first measurement. At the end of each subsequent measurement, Treq n =Treq n-1 -d; If the battery temperature rise rate is between the first rate and the second rate, the coolant target temperature updated a set time interval ago is maintained unchanged.

2. The battery coolant heating control method according to claim 1, wherein: The steps of determining whether heating by a heating device is required and whether heat transfer by a coolant is required according to the temperature range in which the current battery temperature T is located include: If the current battery temperature T is lower than the first set temperature T1, it is determined that the coolant needs to be used for heat transfer, and the coolant drive device is controlled to be in the working state; If the current battery temperature T is greater than or equal to the first set temperature T1 and less than or equal to the second set temperature T2, it is determined that heating by the heating device is not required, but heat equalization by the coolant is required, and the heating device is controlled to be in a non-operating state, while the coolant drive device is controlled to be in an operating state; If the current battery temperature T is greater than the second set temperature T2, it is determined that heating by the heating device is not necessary, and the heating device is controlled to be in a non-operating state.

3. The battery coolant heating control method according to claim 2, wherein: If the current battery temperature T is lower than the first set temperature T1, after determining that the coolant is needed to transfer heat, the coolant driving device is controlled to be in the working state, and the following steps are further included: Further determine whether heating is required using a heating device.

4. The battery coolant heating control method according to claim 3, wherein: The steps of further determining whether heating by a heating device is required include: Determining whether the battery temperature is lower than a third set temperature T3; If the battery temperature is lower than the third set temperature T3, it is determined that the heating device needs to be controlled to heat the coolant; If the battery temperature is greater than the third set temperature T3, the current battery charging rate a is further detected, and according to the relationship between the current battery charging rate a and the set charging rate A, it is determined whether the heating device needs to be operated.

5. The battery coolant heating control method according to claim 4, wherein: The step of determining whether the heating device needs to be operated based on the relationship between the current battery charging rate a and the set charging rate A includes: If the battery charging rate a is greater than the set charging rate A, it is determined that the heating device does not need to be operated; If the charging rate a of the battery is less than or equal to the set charging rate A, the heating device is put into operation and controlled to heat the coolant.

6. The battery coolant heating control method according to claim 4 or 5, characterized in that: The steps of heating the coolant using the heating device include: The timing starts when the heating device starts working, and the current battery temperature T is detected at a set time interval t. The battery temperature rise rate is determined based on the battery temperature difference between the two previous and subsequent detections. An appropriate rule is selected based on the battery temperature rise rate to update the coolant target temperature. The battery temperature rise rate is affected by the change in the coolant target temperature until the battery temperature rise rate is maintained within the required range.

7. The battery coolant heating control method according to claim 6, wherein: The steps of selecting an appropriate rule to update the target coolant temperature according to the battery temperature rise rate, and influencing the battery temperature rise rate by changing the target coolant temperature until the battery temperature rise rate is maintained within a desired range include: If the battery temperature rise rate is less than the first rate, then at the end of the first measurement, the preset coolant target temperature is used as the updated coolant target temperature. At the end of each subsequent measurement, Treq n =Treq n-1 +d, where Treq is the updated coolant target temperature, d is the set progressive value, and n is the number of measurements. When the battery temperature is less than the third set temperature T3 and the coolant is heated by the heating device, the preset coolant target temperature is the first target temperature t1. When the battery charge rate a is less than or equal to the set charge rate A and the coolant is heated by the heating device, the preset coolant target temperature is the second target temperature t2. The calculation formula for the second target temperature t2 is: t2 = t1-a×b+c, where b is the charge rate compensation value and c is the battery temperature compensation value. If the battery temperature rise rate is greater than the second rate, at the end of the first measurement, the preset coolant target temperature is used as the updated coolant target temperature. At the end of each subsequent measurement, Treq n =Treq n-1 -d; If the battery temperature rise rate is between the first rate and the second rate, the coolant target temperature updated a set time interval ago is maintained unchanged.

8. A battery coolant heating control system, characterized in that: include: Detection module, used to detect the current battery temperature T; A control module, configured to execute the heating control method according to any one of claims 1 to 7.

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