Battery thermal management method and system

Abstract

The embodiment of the application discloses a battery thermal management method and system. The method comprises the following steps: acquiring the current working state of a battery pack; if the working state is a charging state, determining whether the battery pack is in an overcharging state; if the battery pack is not in the overcharging state, using a first liquid cooling device to control the heat exchange between the top and bottom liquid cooling plates and the battery pack, so as to liquid cool the battery pack; if the battery pack is in the overcharging state, using a second liquid cooling device to control the heat exchange between the top and bottom liquid cooling plates and the battery pack, so as to liquid cool the battery pack, thereby avoiding excessively high temperature and excessively large temperature difference during battery charging, and especially ensuring that the temperature of the battery is within a safe range during the overcharging process of the battery, and the reliability of the battery is ensured.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of thermal management, in particular to a battery thermal management method and system. BACKGROUND

[0002] The battery thermal management system (BTMS) is a crucial component in new energy vehicles, and its main function is to form a closed-loop regulation system through a heat-conducting medium, a measurement and control unit, and a temperature control device, so that the power battery works within a suitable temperature range to maintain its optimal use state. The temperature of the battery has a significant impact on its performance, life, and safety. Therefore, how to avoid excessive battery temperature and excessive temperature difference is crucial to ensure the safety and efficient operation of the battery system. SUMMARY

[0003] The present application provides a battery thermal management method and system, which can avoid excessive temperature and excessive temperature difference during battery charging, especially ensuring that the temperature of the battery during overcharging is within a safe range, thereby ensuring the reliability of the battery.

[0004] To solve the above problems, in a first aspect, the present application provides a battery thermal management method applied to a battery thermal management system, which includes a top-bottom liquid cooling plate, a first liquid cooling device, and a second liquid cooling device. The method comprises:

[0005] Obtaining the current working state of the battery pack;

[0006] If the working state is a charging state, determining whether the battery pack is in an overcharging state;

[0007] If the battery pack is in a non-overcharging state, using the first liquid cooling device to control the heat exchange between the top-bottom liquid cooling plate and the battery pack to liquid cool the battery pack;

[0008] If the battery pack is in an overcharging state, using the second liquid cooling device to control the heat exchange between the top-bottom liquid cooling plate and the battery pack to liquid cool the battery pack.

[0009] In a second aspect, the present application also provides a battery thermal management system, which comprises:

[0010] A top-bottom liquid cooling plate provided with a liquid cooling flow channel, the liquid cooling flow channel comprising a first flow channel opening and a second flow channel opening, and the top-bottom liquid cooling plate exchanges heat with the battery;

[0011] A first liquid cooling device, one end of the first liquid cooling device being communicated with the first flow channel opening, and the other end of the first liquid cooling device being communicated with the second flow channel opening;

[0012] A second liquid cooling device, one end of the second liquid cooling device is communicated with the first flow channel port, and the other end of the second liquid cooling device is communicated with the second flow channel port.

[0013] The first liquid cooling device is configured to perform liquid cooling on the battery in a non-overcharge state, and the second liquid cooling device is configured to perform liquid cooling on the battery in an overcharge state.

[0014] The battery thermal management method provided in the application comprises the following steps: obtaining a current working state of a battery pack; determining whether the battery pack is in an overcharge state if the working state is a charging state; performing heat exchange control on a top-bottom liquid cooling plate and the battery pack by using a first liquid cooling device to perform liquid cooling on the battery pack if the battery pack is in a non-overcharge state; and performing heat exchange control on the top-bottom liquid cooling plate and the battery pack by using a second liquid cooling device to perform liquid cooling on the battery pack if the battery pack is in an overcharge state. Thus, the temperature of the battery during the charging process can be prevented from being too high and the temperature difference can be prevented from being too large, and in particular, the temperature of the battery during the overcharge process can be ensured to be within a safe range, thereby ensuring the reliability of the battery. BRIEF DESCRIPTION OF DRAWINGS

[0015] In order to more clearly illustrate the technical solutions of the embodiments of the application, the following will briefly introduce the drawings needed to be used in the embodiment description. Obviously, the drawings in the following description are some embodiments of the application, and other drawings can be obtained by those skilled in the art without any creative effort on the basis of these drawings.

[0016] Figure 1 A schematic block diagram of the battery thermal management system provided in the embodiments of the application;

[0017] Figure 2 A flowchart of the battery thermal management method provided in the embodiments of the application. DETAILED DESCRIPTION

[0018] The technical solutions in the embodiments of the application will be described clearly and completely in the following with reference to the drawings in the embodiments of the application. Obviously, the described embodiments are some embodiments of the application, rather than all the embodiments of the application. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without any creative effort belong to the protection scope of the application.

[0019] It should be understood that, when used in the specification and the appended claims, the terms "comprise" and "include" indicate the existence of the described features, integers, steps, operations, elements, and / or components, but do not exclude one or more other features, integers, steps, operations, elements, components, and / or sets thereof.

[0020] It should also be understood that the terms used in the specification of the present application are only for the purpose of describing specific embodiments and are not intended to limit the present application. As used in the specification and the appended claims of the present application, the singular forms "a," "an," and "the" are intended to include the plural forms unless the context clearly indicates otherwise.

[0021] It should be further understood that the term "and / or" used in the specification and the appended claims of the present application means any combination of one or more of the associated listed items and all possible combinations, and includes these combinations.

[0022] In addition, in the present application, unless otherwise explicitly specified or limited in the embodiments, the terms "mounting", "connecting", "connecting" and "fixing" and the like appearing in the embodiments should be understood broadly, for example, the connection can be a fixed connection, or a detachable connection, or integrated, which can be understood, or can be a mechanical connection, an electrical connection, etc. Of course, it can also be directly connected, or indirectly connected through an intermediate medium, or the internal communication of two elements, or the interaction relationship between two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific implementation situation.

[0023] In the related art, in order to shorten the charging time of the electric vehicle, the battery is usually equipped with a fast charging mode and a super charging mode (super fast charging mode). Among them, when the battery is in the fast charging mode, the vehicle-mounted air conditioning system can be added in the thermal management system to assist in cooling the battery; when the battery is in the super charging mode, it requires a lower water inlet temperature of the liquid cooling plate where the battery is located, and a larger flow rate is required.

[0024] However, after adding the vehicle-mounted air conditioning system in the thermal management system to assist in cooling the battery, the water inlet temperature of the liquid cooling plate cannot be reduced to the preset temperature, and the flow rate cannot meet the requirement, thereby causing the battery thermal management system to be unable to effectively reduce the temperature of the battery when the battery is in the super charging mode, resulting in a large temperature difference of the battery, thereby affecting the service life of the battery.

[0025] Therefore, the present application provides a battery thermal management method and system, which can avoid high temperature and large temperature difference during battery charging, especially can ensure that the temperature of the battery is within a safe range during the super charging process of the battery, thereby ensuring the reliability of the battery.

[0026] Please refer to Figure 1 , Figure 1 The schematic block diagram of the battery thermal management system provided by the embodiments of the present application is shown in FIG. 1. As shown in FIG. 1, the present application provides a battery thermal management system, which comprises: Figure 1 ​

[0027] The top-bottom liquid cooling plate 200 is provided with a liquid cooling flow channel, and the liquid cooling flow channel comprises a first flow channel opening and a second flow channel opening. The top-bottom liquid cooling plate 200 exchanges heat with the battery 100.

[0028] The first liquid cooling device 300 is connected to the first flow channel opening at one end and connected to the second flow channel opening at the other end.

[0029] The second liquid cooling device 400 is connected to the first flow channel opening at one end and connected to the second flow channel opening at the other end.

[0030] The first liquid cooling device 300 is configured to at least perform liquid cooling on the battery 100 in a non-supercharged state, and the second liquid cooling device 400 is configured to at least perform liquid cooling on the battery 100 in a supercharged state.

[0031] In the embodiment, the first liquid cooling device 300 can be a liquid cooling device at the vehicle end, that is, the first liquid cooling device 300 can be a liquid cooling device on an electric vehicle. The second liquid cooling device 400 can be a liquid cooling device at the non-vehicle end, that is, the second liquid cooling device 400 can be a liquid cooling device arranged at a charging station. Therefore, the liquid cooling power of the first liquid cooling device 300 is much smaller than the liquid cooling power of the second liquid cooling device 400, and the second liquid cooling device 400 can rapidly reduce the temperature of the battery 100, thereby ensuring that the temperature of the battery 100 is within a safe range during the supercharging process of the battery 100, and ensuring the reliability of the battery 100.

[0032] At the same time, the first liquid cooling device 300 can be provided with a water pump, a heat exchange device and a heater. Similarly, the second liquid cooling device 400 can also be provided with the first liquid cooling device 300, but the liquid cooling power of the second liquid cooling device 400 needs to be much greater than the liquid cooling power of the first liquid cooling device 300.

[0033] Specifically, the battery 100 mentioned in the present application can be understood as a battery pack, and the battery pack is liquid-cooled in a top-bottom liquid cooling manner. The top-bottom liquid cooling technology realizes efficient temperature control by installing a liquid cooling plate on the top and bottom of the battery 100 and using forced convection of the cooling liquid in the channel to carry away heat. When the first liquid cooling device 300 is used to liquid cool the battery 100, the temperature at the liquid inlet of the top-bottom liquid cooling plate 200 can be 15℃ under normal circumstances, and the liquid cooling flow rate can be 10L / min. When the second liquid cooling device 400 is used to liquid cool the battery 100, the temperature at the liquid inlet of the top-bottom liquid cooling plate 200 can be 10℃ under normal circumstances, and the liquid cooling flow rate can be 20L / min.

[0034] It should be noted that the reason why the second liquid cooling device 400 is added to the thermal management system is that after the battery pack adopts the top and bottom liquid cooling mode for liquid cooling, the battery 100 is configured with an overcharge mode (4C high-rate charging mode), and it is found that the top and bottom liquid cooling mode cannot control the battery pack temperature and the temperature difference within a safe range, and then the vehicle air conditioning system is added to assist in cooling the battery 100. However, in the process of adding the vehicle air conditioning system to assist in cooling the battery 100, the battery pack temperature and the temperature difference still cannot be controlled within a safe range, and then the second liquid cooling device 400 is added to the thermal management system, and the second liquid cooling device 400 is configured to at least liquid cool the battery 100 in the overcharge state.

[0035] In addition, the non-overcharge state mentioned in the present application can be that the battery 100 is in a fast charging state, or the battery 100 is in a normal charging state, or the battery 100 is in a discharging state (the vehicle in which the battery 100 is located is in a driving state).

[0036] The battery thermal management system provided by the present application comprises a top and bottom liquid cooling plate 200, a first liquid cooling device 300 and a second liquid cooling device 400. The top and bottom liquid cooling plate 200 is provided with a liquid cooling flow channel, and the liquid cooling flow channel comprises a first flow channel port and a second flow channel port. The top and bottom liquid cooling plate 200 exchanges heat with the battery 100. One end of the first liquid cooling device 300 communicates with the first flow channel port, and the other end of the first liquid cooling device 300 communicates with the second flow channel port. One end of the second liquid cooling device 400 communicates with the first flow channel port, and the other end of the second liquid cooling device 400 communicates with the second flow channel port. The first liquid cooling device 300 is configured to at least liquid cool the battery 100 in a non-overcharge state, and the second liquid cooling device 400 is configured to at least liquid cool the battery 100 in an overcharge state. Thus, the temperature of the battery 100 during charging can be prevented from being too high and the temperature difference can be prevented from being too large, and in particular, the temperature of the battery 100 during overcharge can be ensured to be within a safe range, thereby ensuring the reliability of the battery 100.

[0037] In some embodiments, as shown in Figure 1 The battery thermal management system further comprises a first three-way valve T1 and a second three-way valve T2. The first end 1 of the first three-way valve T1 communicates with the first flow channel port, the second end 2 of the first three-way valve T1 communicates with one end of the first liquid cooling device 300, and the third end 3 of the first three-way valve T1 communicates with one end of the second liquid cooling device 400. The first end 1 of the second three-way valve T2 communicates with the other end of the first liquid cooling device 300, the second end 2 of the second three-way valve T2 communicates with the second flow channel port, and the third end 3 of the second three-way valve T2 communicates with the other end of the second liquid cooling device 400.

[0038] In this embodiment, the first three-way valve T1 and the second three-way valve T2 can isolate the first liquid cooling device 300 and the second liquid cooling device 400 through water circuits, so that when the battery 100 is in a non-overcharged state, the first liquid cooling device 300 can liquid cool the battery 100 independently, and when the battery 100 is in an overcharged state, the second liquid cooling device 400 can liquid cool the battery 100 independently.

[0039] Specifically, when battery 100 is not in an overcharged state, the first terminal 1 and the third terminal 3 of the first three-way valve T1 are connected, while the first terminal 1 and the second terminal 2 of the first three-way valve T1 are not connected. The first terminal 1 and the second terminal 2 of the second three-way valve T2 are connected, while the second terminal 2 and the third terminal 3 of the second three-way valve T2 are not connected. Therefore, the first liquid cooling device 300 can be used to liquid cool battery 100 independently. When battery 100 is in an overcharged state, the first terminal 1 and the third terminal 3 of the first three-way valve T1 are not connected, while the first terminal 1 and the second terminal 2 of the first three-way valve T1 are connected. The first terminal 1 and the second terminal 2 of the second three-way valve T2 are not connected, while the second terminal 2 and the third terminal 3 of the second three-way valve T2 are connected. Therefore, the first liquid cooling device 300 can be used to liquid cool battery 100 independently. Both the first three-way valve T1 and the second three-way valve T2 can be controlled by the battery management system of the battery pack.

[0040] In some embodiments, such as Figure 1 As shown, the battery thermal management system also includes a liquid-cooled socket 500; wherein, the first end of the liquid-cooled socket 500 is connected to the third end 3 of the first three-way valve T1, the second end of the liquid-cooled socket 500 is connected to the third end 3 of the second three-way valve T2, the third end of the liquid-cooled socket 500 is connected to one end of the second liquid-cooling device 400, and the fourth end of the liquid-cooled socket 500 is connected to the other end of the second liquid-cooling device 400; the first end and the third end of the liquid-cooled socket 500 are connected, and the second end and the fourth end of the liquid-cooled socket 500 are connected.

[0041] In this embodiment, the liquid cooling socket 500 can be installed inside the vehicle body. When the battery 100 needs to be overcharged, it can be connected to the second liquid cooling device 400 through the liquid cooling socket 500, so that the second liquid cooling device 400 can liquid cool the battery 100 in the overcharged state, thereby ensuring that the temperature and temperature difference of the battery 100 in the overcharged state are within a safe range.

[0042] The Liquid-Cooled Socket 500 is a charging socket that utilizes liquid cooling technology, primarily used in electric vehicle charging systems. The Liquid-Cooled Socket 500 uses a coolant to reduce temperature during charging, thereby improving charging efficiency and safety. Its advantages include effectively lowering the charging temperature, thus reducing the required cable cross-sectional area, lightening the weight of the plug and cable, and improving ease of operation. Furthermore, the Liquid-Cooled Socket 500 can help charging stations achieve higher and more stable charging power; for example, during high-power charging, it can stably achieve a charging power of 500kW, and even reach 700kW for short periods.

[0043] In some embodiments, such as Figure 1 As shown, the top and bottom liquid cooling plates 200 include a first liquid cooling plate 201 and a second liquid cooling plate 202, and the liquid cooling channels include a first liquid cooling channel and a second liquid cooling channel; wherein, the first liquid cooling channel is disposed in the first liquid cooling plate 201, and the second liquid cooling channel is disposed in the second liquid cooling plate 202; one end of the first liquid cooling channel and one end of the second liquid cooling channel are connected to the first channel opening by a first tee connector T5, and the other end of the first liquid cooling channel and the other end of the second liquid cooling channel are connected to the second channel opening by a second tee connector T6.

[0044] In this embodiment, the first liquid cooling plate 201 and the second liquid cooling plate 202 can be located on corresponding sides of the battery 100. Specifically, the first liquid cooling plate 201 can be located on the top of the battery 100, and the second liquid cooling plate 202 can be located on the bottom of the battery 100, so that the battery 100 can be liquid cooled by a top-bottom liquid cooling method. At the same time, in order to ensure that the battery 100 can achieve top-bottom liquid cooling, one end of the first liquid cooling channel and one end of the second liquid cooling channel are connected to the first channel opening by a first tee connector T5, and the other end of the first liquid cooling channel and the other end of the second liquid cooling channel are connected to the second channel opening by a second tee connector T6.

[0045] Specifically, the first end 1 of the first tee connector T5 is connected to one end of the first liquid cooling channel, the second end 2 of the first tee connector T5 is connected to one end of the second liquid cooling channel, and the third end 3 of the first tee connector T5 is connected to the opening of the first channel; the first end 1 of the second tee connector T6 is connected to the other end of the first liquid cooling channel, the second end 2 of the second tee connector T6 is connected to the other end of the second liquid cooling channel, and the third end 3 of the second tee connector T6 is connected to the opening of the second liquid cooling channel.

[0046] In some embodiments, the liquid cooling flow rate of the first liquid cooling channel is less than the liquid cooling flow rate of the second liquid cooling channel.

[0047] In the embodiment, the first liquid cooling plate 201 is arranged at the top of the battery 100, and the second liquid cooling plate 202 is arranged at the bottom of the battery 100, so that the battery pack can achieve better liquid cooling effect. However, this mode may cause the cooling effect of the top of the battery 100 to be better, and the cooling effect of the bottom of the battery 100 to be poor, thereby causing a large temperature difference between the top and the bottom.

[0048] For example, if the first liquid cooling plate 201 is a stamping liquid cooling plate, and the second liquid cooling plate 202 is an extrusion liquid cooling plate, and the liquid cooling effect of the stamping liquid cooling plate is better than that of the extrusion liquid cooling plate, then the cooling effect of the top of the battery 100 will be better, and the cooling effect of the bottom of the battery 100 will be poor, thereby causing a large temperature difference between the top and the bottom.

[0049] Therefore, the liquid cooling flow rate of the first liquid cooling flow channel needs to be less than that of the second liquid cooling flow channel. Specifically, the liquid cooling flow rate ratio between the first liquid cooling flow channel and the second liquid cooling flow channel can be 3:7.

[0050] Further, in the process of achieving the liquid cooling flow rate of the first liquid cooling flow channel being less than that of the second liquid cooling flow channel, the inner diameter of the first end 1 of the first three-way joint T5 can be less than that of the second end 2 of the first three-way joint T5, and the inner diameter of the first end 1 of the second three-way joint T6 can be less than that of the second end 2 of the second three-way joint T6.

[0051] It should be noted that the liquid cooling flow rate of the first liquid cooling flow channel being less than that of the second liquid cooling flow channel can be selected according to actual application, and the present application does not make specific limitation. For example, the first three-way joint T5 and the second three-way joint can be replaced by a three-way valve to achieve the same effect.

[0052] In some embodiments, the first liquid cooling plate 201 includes a stamping liquid cooling plate, and the second liquid cooling plate 202 includes an extrusion liquid cooling plate.

[0053] Specifically, the liquid cooling plate configured by the battery pack is usually a stamping liquid cooling plate. Since the present application adopts a top-bottom liquid cooling mode, the stamping liquid cooling plate placed at the bottom of the battery 100 cannot bear force, and therefore the liquid cooling plate at the bottom of the battery 100 needs to be configured as an extrusion liquid cooling plate.

[0054] The stamping liquid cooling plate is a liquid cooling plate manufactured by stamping process, and is usually used to manufacture cooling plates with simple shapes. The stamping liquid cooling plate has the advantages of arbitrary design of flow channel, large contact area, good heat exchange effect, high production efficiency, good pressure resistance and strength, etc. In the manufacturing process, the stamping liquid cooling plate needs to be subjected to degreasing treatment to remove oil stains and impurities on the surface, so as to ensure that the stamping liquid cooling plate can play the best performance in use.

[0055] The extruded liquid cooling plate is a product combining extrusion technology and liquid cooling technology, mainly used in occasions requiring efficient heat dissipation and heat preservation. The extruded liquid cooling plate can combine the heat preservation performance of the extruded plate and the heat dissipation performance of the liquid cooling plate, and is used in occasions requiring efficient heat dissipation and heat preservation.

[0056] In some embodiments, the battery thermal management system further comprises an exhaust assembly; one end of the exhaust assembly is respectively communicated with the first flow channel port and one end of the first liquid cooling device 300, and the other end of the exhaust assembly is communicated with the outside.

[0057] Specifically, the application can also be provided with an exhaust assembly at the first flow channel port, so as to facilitate the exhaust of air in the pipeline, thereby further improving the liquid cooling effect of the top and bottom liquid cooling. Since the liquid cooling power of the second liquid cooling device 400 is much greater than that of the first liquid cooling device 300, the exhaust assembly can be arranged in the vehicle and used in cooperation with the first liquid cooling device 300, thereby further improving the liquid cooling effect of the first liquid cooling device 300.

[0058] Further, in some embodiments, as shown in Figure 1 The exhaust assembly comprises an exhaust pipe and a third three-way valve T3; wherein the first end 1 of the third three-way valve T3 is communicated with the first flow channel port, the second end 2 of the third three-way valve T3 is communicated with one end of the first liquid cooling device 300, the third end 3 of the third three-way valve T3 is communicated with one end of the exhaust pipe, and the other end of the exhaust pipe is communicated with the outside.

[0059] In this embodiment, by arranging the third three-way valve T3 at the first flow channel port and one end of the first liquid cooling device 300, the first end 1 and the third end 3 of the third three-way valve T3 are communicated when it is needed to exhaust the pipeline, and the first end 1 and the second end 2 of the third three-way valve T3 are communicated and the first end 1 and the third end 3 of the third three-way valve T3 are not communicated when it is not needed to exhaust the pipeline.

[0060] Further, in some embodiments, as shown in Figure 1 The exhaust assembly further comprises a liquid injection pot 600 and a fourth three-way valve T4; wherein the liquid injection pot 600 is communicated with the first end 1 of the fourth three-way valve T4, the second end 2 of the fourth three-way valve T4 is communicated with the second end 2 of the third three-way valve T3, the third end 3 of the fourth three-way valve T4 is communicated with one end of the first liquid cooling device 300, and the other end of the exhaust pipe is communicated with the outside through the liquid injection pot 600.

[0061] Specifically, the application can also be provided with a fourth three-way valve T4 between the third three-way valve T3 and the first liquid cooling device 300, and a liquid injection pot 600 between the third three-way valve T3 and the fourth three-way valve T4, which can not only avoid the reduction of cooling liquid during the exhaust process of the pipeline, but also facilitate the liquid supplement of the pipeline.

[0062] In the embodiment, when only exhaust is needed in the pipeline, the first end 1 and the third end 3 of the third three-way pipe can be connected. When the battery 100 needs to be liquid-cooled by the first liquid cooling device 300 and exhaust is needed in the pipeline, the first end 1 and the third end 3 of the third three-way pipe and the first end 1 and the second end 2 of the fourth three-way pipe can be connected. The first end 1 and the second end 2 of the third three-way pipe can be connected or not connected, and the second end 2 of the fourth connecting pipe can be connected or not connected.

[0063] It should be noted that the third three-way valve T3 and the fourth three-way valve T4 can also be provided as a three-way joint, which can also achieve the purpose of liquid-cooling the battery 100 by the first liquid cooling device 300 and exhausting in the pipeline.

[0064] In addition, when only exhaust is needed in the pipeline, the first end 1 and the third end 3 of the third three-way pipe can be connected.

[0065] It can be understood that the battery thermal management system provided in the above embodiment is only an example, and the battery thermal management system described in the embodiments of the present application is used to more clearly illustrate the technical solutions of the embodiments of the present application, and does not constitute a limitation on the technical solutions provided by the embodiments of the present application. Those skilled in the art can know that the technical solutions provided by the embodiments of the present application are also applicable to similar technical problems as the system evolves and new business scenarios appear. The following will be described in detail.

[0066] It should be noted that the description order of the following embodiments does not constitute a limitation on the preferred order of the embodiments. The thermal management method of the battery thermal management system will be described in detail below. At the same time, the thermal management method of the battery thermal management system provided by the present application can be executed by the battery management system.

[0067] Please refer to Figure 2 , Figure 2 The flowchart of the battery thermal management method provided by the embodiments of the present application is shown in FIG. 10. As shown in FIG. 10, the method comprises steps S110-S140. Figure 2

[0068] S110, obtaining the current working state of the battery pack.

[0069] Specifically, the current working state of the battery pack can be obtained by the battery management system of the battery pack, which can be identified and judged by collecting the charge and discharge of the battery pack, and then the current working state of the battery pack is obtained. The working state of the battery pack includes the charging state and the discharging state.

[0070] ​In some embodiments, after step S110, further comprising the step of: if the working state is the discharging state, determining whether the vehicle in which the battery pack is located is in the driving state; if the vehicle is in the driving state, using the first liquid cooling device to control the heat exchange between the top and bottom liquid cooling plates and the battery pack to liquid cool the battery pack.

[0071] In the embodiment, the working state of the battery pack further includes the discharging state. Since the battery pack generates heat when discharging, the temperature of the battery pack will increase. Therefore, when the current working state of the battery pack is obtained and it is determined that the working state is the discharging state, the thermal management system needs to be started to perform thermal management on the battery pack, so as to ensure that the temperature of the battery pack is within a safe range during discharging. Meanwhile, the battery pack is arranged in the vehicle. After it is determined that the battery pack is in the discharging state, it is further needed to determine whether the vehicle in which the battery pack is located is in the driving state. If the vehicle is in the driving state, the flow rate and temperature of the liquid inlet of the top and bottom liquid cooling plates can be controlled by using the first liquid cooling device, so as to ensure that the temperature and temperature difference of the battery pack are within a safe range.

[0072] S120, if the working state is the charging state, determining whether the battery pack is in the overcharging state.

[0073] In the embodiment, when the battery pack is in the charging state, it can be in the ordinary charging state, the fast charging state or the overcharging state. When the battery pack is in the fast charging state, the heat generated by the battery pack is higher than that in the ordinary charging state. The first liquid cooling device can be used to control the heat exchange between the top and bottom liquid cooling plates and the battery pack to liquid cool the battery pack. When the battery pack is in the overcharging state, the heat generated by the battery pack is higher than that in the fast charging state. If the first liquid cooling device is used to control the heat exchange between the top and bottom liquid cooling plates and the battery pack, it cannot ensure that the temperature and temperature difference of the battery pack are within a safe range. Therefore, when it is determined that the battery pack is in the charging state, it is further needed to determine whether the battery pack is in the overcharging state, so as to ensure that the temperature and temperature difference of the battery pack are within a safe range during charging.

[0074] S130, if the battery pack is in the non-overcharging state, using the first liquid cooling device to control the heat exchange between the top and bottom liquid cooling plates and the battery pack to liquid cool the battery pack.

[0075] In the embodiment, the non-overcharging state includes the fast charging state and the ordinary charging state. When the battery pack is in the non-overcharging state, the first liquid cooling device can be used to control the flow rate and temperature of the liquid inlet of the top and bottom liquid cooling plates, so that the liquid in the top and bottom liquid cooling plates can fully liquid cool the battery pack, thereby ensuring that the temperature and temperature difference of the battery pack are within a safe range.

[0076] In some embodiments, when the first liquid cooling device is used to control heat exchange between the top-and-bottom liquid cooling plate and the battery pack, a first liquid cooling temperature at an inlet of a liquid cooling flow channel of the top-and-bottom liquid cooling plate is obtained; if the first liquid cooling temperature is greater than or equal to a preset first temperature, it is determined whether a first liquid cooling flow rate at the inlet reaches a preset first flow rate; if the first liquid cooling flow rate reaches the first flow rate, the first end and the second end of the first three-way valve are controlled to be in communication, and the second end and the third end of the second three-way valve are controlled to be in communication; the second liquid cooling device is used to adjust the first liquid cooling flow rate at the inlet to a preset second flow rate; wherein the second flow rate is greater than the first flow rate.

[0077] In the present embodiment, when the first liquid cooling device is used to control heat exchange between the top-and-bottom liquid cooling plate and the battery pack, the temperature of the liquid at the inlet of the top-and-bottom liquid cooling plate, i.e., the first liquid cooling temperature, can be too high due to external environmental factors, and can be higher than the preset first temperature, which can be 15℃. At this time, the first liquid cooling device needs to be used to increase the flow rate at the inlet, but the flow rate at the inlet, i.e., the first liquid cooling flow rate, can be the maximum flow rate that the first liquid cooling device can increase, i.e., the first flow rate. At this time, if the first liquid cooling device is continued to be used to control heat exchange between the top-and-bottom liquid cooling plate and the battery pack, the temperature and temperature difference of the battery pack cannot be guaranteed to be within a safe range. The liquid cooling power of the second liquid cooling device is much greater than that of the first liquid cooling device in the present application. Therefore, after it is determined that the first liquid cooling flow rate reaches the first flow rate, the first end and the second end of the first three-way valve are controlled to be in communication, and the second end and the third end of the second three-way valve are controlled to be in communication, and the second liquid cooling device is used to adjust the first liquid cooling flow rate at the inlet to a preset second flow rate, so as to guarantee that the temperature and temperature difference of the battery pack are within a safe range.

[0078] In some embodiments, after the second liquid cooling device is used to adjust the first liquid cooling flow rate at the inlet to the preset second flow rate, the following steps are further included: after a preset first time, a second liquid cooling temperature at the inlet is obtained; if the second liquid cooling temperature is less than or equal to a preset second temperature, the first end and the third end of the first three-way valve are controlled to be in communication, and the first end and the second end of the second three-way valve are controlled to be in communication; wherein the second temperature is less than the first temperature; the first liquid cooling device is used to adjust the liquid cooling flow rate at the inlet to a preset third flow rate; wherein the third flow rate is less than or equal to the first flow rate.

[0079] In the embodiment, the second temperature can be the first temperature. Since the battery pack is in the non-fast charging state, if the second liquid cooling device is continuously used to control the heat exchange between the top and bottom liquid cooling plate and the battery pack, it will cause waste of resources, so in the process of adjusting the first liquid cooling flow at the liquid inlet to the preset second flow by using the second liquid cooling device, after the preset first time, the second liquid cooling temperature at the liquid inlet is obtained. If the second liquid cooling temperature is less than or equal to the preset second temperature, the communication between the first end and the third end of the first three-way valve and the communication between the first end and the second end of the second three-way valve are controlled, and the liquid cooling flow at the liquid inlet is adjusted to the preset third flow by using the first liquid cooling device. Wherein, the third flow can be less than or equal to the first flow.

[0080] In some embodiments, the first liquid cooling device is used to control the heat exchange between the top and bottom liquid cooling plate and the battery pack to liquid cool the battery pack, comprising: if the first liquid cooling flow does not reach the first flow, controlling the communication between the first end and the third end of the first three-way valve and the communication between the first end and the second end of the second three-way valve; using the first liquid cooling device to increase the first liquid cooling flow at the liquid inlet to the first flow to liquid cool the battery pack.

[0081] Specifically, the flow at the liquid inlet of the top and bottom liquid cooling plate can be controlled by the first liquid cooling device. When the flow at the liquid inlet is controlled by the first liquid cooling device, the maximum flow that can be reached at the liquid inlet can be the first flow. When the first liquid cooling flow does not reach the first flow, the communication between the first end and the third end of the first three-way valve and the communication between the first end and the second end of the second three-way valve can be controlled; the first liquid cooling flow at the liquid inlet is increased to the first flow by using the first liquid cooling device to liquid cool the battery pack.

[0082] In some embodiments, after obtaining the first liquid cooling temperature at the liquid inlet of the liquid cooling flow channel of the top and bottom liquid cooling plate, it further comprises: if the first liquid cooling temperature is less than or equal to the preset third temperature, controlling the communication between the first end and the third end of the first three-way valve and the communication between the first end and the second end of the second three-way valve; wherein the third temperature is less than the first temperature; using the heater in the first liquid cooling device to increase the liquid cooling temperature at the liquid inlet to the preset fourth temperature to heat the battery pack.

[0083] Specifically, during the charging process of the battery pack, the liquid in the pipeline may be too low due to the low external temperature, which may cause the temperature at the liquid inlet of the top and bottom liquid cooling plate to be too low, and the battery pack needs to be heated to normally charge. However, the battery pack provided in the application does not use a heating film or the like to heat, and the first liquid cooling device is provided with a heater, and when the first liquid cooling temperature is less than or equal to the preset third temperature, the first three-way valve is controlled to be communicated between the first end and the third end, and the second three-way valve is communicated between the first end and the second end, and the heater in the first liquid cooling device is used to raise the liquid cooling temperature at the liquid inlet to the preset fourth temperature, so as to heat the battery pack, thereby ensuring that the battery pack normally charges.

[0084] That is, the heating and cooling of the battery pack mentioned in the application are both performed by the top and bottom liquid cooling plate to control the temperature and temperature difference, thereby reducing the production cost of the battery pack and improving the safety and reliability of the battery pack.

[0085] S140, if the battery pack is in an overcharging state, the second liquid cooling device is used to control the heat exchange between the top and bottom liquid cooling plate and the battery pack to liquid cool the battery pack.

[0086] In the embodiment, the liquid cooling power of the second liquid cooling device is much larger than that of the first liquid cooling device, which can increase the temperature and flow rate at the liquid inlet of the top and bottom liquid cooling plate, thereby ensuring that the temperature and temperature difference of the battery pack during overcharging are within a safe and controllable range, and improving the safety and reliability of the battery pack.

[0087] In some embodiments, step S140 includes the steps of: if the battery pack is in an overcharging state, obtaining a third liquid cooling temperature at the liquid inlet of the liquid cooling flow channel of the top and bottom liquid cooling plate; if the third liquid cooling temperature is greater than or equal to a preset fifth temperature, controlling the first three-way valve to be communicated between the first end and the second end, and the second three-way valve to be communicated between the second end and the third end; and adjusting the liquid cooling flow rate at the liquid inlet to a preset fourth flow rate by using the second liquid cooling device to liquid cool the battery pack.

[0088] Specifically, when the battery pack in the overcharge state adopts the second liquid cooling device to realize thermal management, the temperature at the liquid inlet of the top and bottom liquid cooling plates at the battery pack is usually within a preset temperature range, which can be characterized by a fifth temperature and a sixth temperature, the fifth temperature being greater than the sixth temperature, and the average value between the fifth temperature and the sixth temperature being 10℃. When the temperature at the liquid inlet of the liquid cooling flow channel of the top and bottom liquid cooling plates, i.e., the third liquid cooling temperature, is higher than the fifth temperature, it cannot be guaranteed that the temperature and temperature difference of the battery pack in the overcharge state are within a safe range. At this time, the communication between the first end and the third end of the first three-way valve and the communication between the first end and the third end of the second three-way valve need to be controlled, and the second liquid cooling device is adopted to adjust the liquid cooling flow at the liquid inlet to a preset fourth flow rate, so as to guarantee that the temperature at the liquid inlet is within the preset temperature range, and in turn, the temperature and temperature difference of the battery pack in the overcharge state can be guaranteed to be within a safe range.

[0089] In some embodiments, after adjusting the liquid cooling flow at the liquid inlet to the preset fourth flow rate by using the second liquid cooling device to liquid cool the battery pack, the method further comprises: after a preset second time, acquiring a fourth liquid cooling temperature at the liquid inlet; if the fourth liquid cooling temperature is less than or equal to the preset sixth temperature, adjusting the liquid cooling flow at the liquid inlet to a preset fifth flow rate; wherein the fifth flow rate is less than or equal to the fourth flow rate.

[0090] In the present embodiment, since the liquid cooling flow at the liquid inlet is increased to the fourth flow rate, which is relatively large, it can quickly reduce the temperature at the liquid inlet to the sixth temperature. At this time, if the fourth flow rate is continuously used, it may cause the temperature at the liquid inlet to be too low. Therefore, after a preset second time, the fourth liquid cooling temperature at the liquid inlet is acquired; if the fourth liquid cooling temperature is less than or equal to the preset sixth temperature, the liquid cooling flow at the liquid inlet is adjusted to a preset fifth flow rate. The fifth flow rate can be 20 L / min.

[0091] In some embodiments, before using the first liquid cooling device to control the heat exchange between the top and bottom liquid cooling plates and the battery pack to liquid cool the battery pack, the method further comprises: if an exhaust instruction of the battery thermal management system is received, controlling the first end and the third end of the third three-way valve to communicate, so as to exhaust the gas in the battery thermal management system through the exhaust pipe; if the exhaust instruction is not received, controlling the first end and the second end of the third three-way valve to communicate.

[0092] Specifically, the application can also be provided with an exhaust assembly at the first flow channel opening, so as to facilitate the exhaust of air in the pipeline, and in turn, the liquid cooling effect of the top and bottom liquid cooling can be further improved. Since the liquid cooling power of the second liquid cooling device is much greater than that of the first liquid cooling device, the exhaust assembly can be arranged in the vehicle and used in cooperation with the first liquid cooling device, so as to further improve the liquid cooling effect of the first liquid cooling device.

[0093] In some embodiments, the communication between the first end and the third end of the third three-way valve is controlled to discharge the gas in the battery thermal management system through the exhaust pipe, comprising: controlling the communication between the first end and the third end of the third three-way valve, and the communication between the first end and the third end of the fourth three-way valve to discharge the gas in the battery thermal management system through the exhaust pipe and the liquid injection pot in sequence.

[0094] In the embodiment, by arranging the third three-way valve at the first flow channel port and one end of the first liquid cooling device, the first end and the third end of the third three-way valve are communicated when the pipeline needs to be exhausted, and the first end and the second end of the third three-way valve are communicated and the first end and the third end of the third three-way valve are not communicated when the pipeline does not need to be exhausted.

[0095] In some embodiments, after the communication between the first end and the second end of the third three-way valve is controlled, the communication between the second end and the third end of the fourth three-way valve is further controlled.

[0096] Specifically, the application can further arrange a fourth three-way valve between the third three-way valve and the first liquid cooling device, and arrange a liquid injection pot between the third three-way valve and the fourth three-way valve, which can not only avoid the reduction of cooling liquid during the pipeline exhaust process, but also facilitate the liquid supplement of the pipeline.

[0097] In the embodiment, when the pipeline only needs to be exhausted, the first end and the third end of the third three-way valve can be communicated. When the first liquid cooling device needs to be used to liquid cool the battery and the pipeline needs to be exhausted, the first end and the third end of the third three-way valve are communicated and the first end and the second end of the fourth three-way valve are communicated. The first end and the second end of the third three-way valve can be communicated or not communicated, and the second end of the fourth three-way valve can be communicated or not communicated.

[0098] The battery thermal management method provided by the application can obtain the current working state of the battery pack, determine whether the battery pack is in an overcharging state if the working state is a charging state, use a first liquid cooling device to control the heat exchange between the top and bottom liquid cooling plates and the battery pack to liquid cool the battery pack if the battery pack is in a non-overcharging state, and use a second liquid cooling device to control the heat exchange between the top and bottom liquid cooling plates and the battery pack to liquid cool the battery pack if the battery pack is in an overcharging state, thereby avoiding the excessively high temperature and excessively large temperature difference during battery charging, and especially ensuring that the temperature of the battery during the overcharging process is within a safe range, and ensuring the reliability of the battery.

[0099] The above merely provides the specific implementation of the present application, but the protection scope of the present application is not limited to this. Any person skilled in the art can easily think of various equivalent modifications or replacements within the technical range disclosed by the present application, and these modifications or replacements should be covered in the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A method of battery thermal management, the method comprising: The application is applied to a battery thermal management system, and the battery thermal management system comprises a top-bottom liquid cooling plate, a first liquid cooling device, a second liquid cooling device, a first three-way valve and a second three-way valve; the method comprises the following steps: acquiring a current working state of a battery pack; if the working state is a charging state, determining whether the battery pack is in an overcharging state; if the battery pack is not in the overcharging state, using the first liquid cooling device to perform heat exchange control on the top-bottom liquid cooling plate and the battery pack, so as to perform liquid cooling on the battery pack; if the battery pack is in the overcharging state, using the second liquid cooling device to perform heat exchange control on the top-bottom liquid cooling plate and the battery pack, so as to perform liquid cooling on the battery pack; during the heat exchange control on the top-bottom liquid cooling plate and the battery pack by using the first liquid cooling device, acquiring a first liquid cooling temperature at an inlet of a liquid cooling flow channel of the top-bottom liquid cooling plate; if the first liquid cooling temperature is greater than or equal to a preset first temperature, determining whether a first liquid cooling flow rate at the inlet reaches a preset first flow rate; if the first liquid cooling flow rate reaches the first flow rate, controlling the first three-way valve to be in communication between a first end and a second end thereof, and the second three-way valve to be in communication between a second end and a third end thereof; using the second liquid cooling device to adjust the first liquid cooling flow rate at the inlet to a preset second flow rate; wherein the second flow rate is greater than the first flow rate.

2. The battery thermal management method of claim 1, wherein, after the step of acquiring the current working state of the battery pack, the method further comprises the following steps: if the working state is a discharging state, determining whether a vehicle in which the battery pack is located is in a driving state; if the vehicle is in the driving state, using the first liquid cooling device to perform heat exchange control on the top-bottom liquid cooling plate and the battery pack, so as to perform liquid cooling on the battery pack.

3. The battery thermal management method of claim 1, wherein, after the step of using the second liquid cooling device to adjust the first liquid cooling flow rate at the inlet to the preset second flow rate, the method further comprises the following steps: after a preset first time, acquiring a second liquid cooling temperature at the inlet; if the second liquid cooling temperature is less than or equal to a preset second temperature, controlling the first three-way valve to be in communication between the first end and the third end thereof, and the second three-way valve to be in communication between the first end and the second end thereof; wherein the second temperature is less than the first temperature; using the first liquid cooling device to adjust the liquid cooling flow rate at the inlet to a preset third flow rate; wherein the third flow rate is less than or equal to the first flow rate.

4. The battery thermal management method of claim 1, wherein, the step of using the first liquid cooling device to perform heat exchange control on the top-bottom liquid cooling plate and the battery pack, so as to perform liquid cooling on the battery pack, comprises the following steps: if the first liquid cooling flow rate does not reach the first flow rate, controlling the first three-way valve to be in communication between the first end and the third end thereof, and the second three-way valve to be in communication between the first end and the second end thereof; using the first liquid cooling device to increase the first liquid cooling flow rate at the inlet to the first flow rate, so as to perform liquid cooling on the battery pack.

5. The battery thermal management method of claim 1, wherein, after the step of acquiring the first liquid cooling temperature at the inlet of the liquid cooling flow channel of the top-bottom liquid cooling plate, the method further comprises the following steps: If the first liquid cooling temperature is less than or equal to a preset third temperature, the first end and the third end of the first three-way valve are controlled to be communicated, and the first end and the second end of the second three-way valve are controlled to be communicated; wherein the third temperature is less than the first temperature; The heater in the first liquid cooling device is used to increase the liquid cooling temperature at the liquid inlet to a preset fourth temperature, so as to heat the battery pack.

6. The battery thermal management method of claim 1, wherein, If the battery pack is in an over-charged state, the second liquid cooling device is used to control the heat exchange between the top and bottom liquid cooling plate and the battery pack, so as to liquid cool the battery pack, including: If the battery pack is in an over-charged state, the third liquid cooling temperature at the liquid inlet of the liquid cooling flow channel of the top and bottom liquid cooling plate is obtained; If the third liquid cooling temperature is greater than or equal to a preset fifth temperature, the first end and the second end of the first three-way valve are controlled to be communicated, and the second end and the third end of the second three-way valve are controlled to be communicated; The second liquid cooling device is used to adjust the liquid cooling flow at the liquid inlet to a preset fourth flow, so as to liquid cool the battery pack.

7. The battery thermal management method of claim 6, wherein, After the second liquid cooling device is used to adjust the liquid cooling flow at the liquid inlet to a preset fourth flow, so as to liquid cool the battery pack, further including: After a preset second time, the fourth liquid cooling temperature at the liquid inlet is obtained; If the fourth liquid cooling temperature is less than or equal to a preset sixth temperature, the liquid cooling flow at the liquid inlet is adjusted to a preset fifth flow; wherein the fifth flow is less than or equal to the fourth flow.

8. The battery thermal management method of any one of claims 1-7, wherein, The battery thermal management system further includes a third three-way valve and an exhaust pipe; Before the first liquid cooling device is used to control the heat exchange between the top and bottom liquid cooling plate and the battery pack, so as to liquid cool the battery pack, further including: If the exhaust instruction of the battery thermal management system is received, the first end and the third end of the third three-way valve are controlled to be communicated, so that the gas in the battery thermal management system is exhausted from the exhaust pipe; If the exhaust instruction is not received, the first end and the second end of the third three-way valve are controlled to be communicated.

9. The battery thermal management method of claim 8, wherein, The battery thermal management system further includes a fourth three-way valve and a liquid injection pot; The first end and the third end of the third three-way valve are controlled to be communicated, and the first end and the third end of the fourth three-way valve are controlled to be communicated, so that the gas in the battery thermal management system is sequentially exhausted from the exhaust pipe and the liquid injection pot; After the first end and the second end of the third three-way valve are controlled to be communicated, further including: The second end and the third end of the fourth three-way valve are controlled to be communicated. The battery thermal management system includes:

10. A battery thermal management system, characterized by, A top and bottom liquid cooling plate is provided with a liquid cooling flow channel, the liquid cooling flow channel includes a first flow channel and a second flow channel, and the top and bottom liquid cooling plate exchanges heat with the battery; ​ A first liquid cooling device, one end of the first liquid cooling device being communicated with the first flow channel port, and the other end of the first liquid cooling device being communicated with the second flow channel port; A second liquid cooling device, one end of the second liquid cooling device being communicated with the first flow channel port, and the other end of the second liquid cooling device being communicated with the second flow channel port; The first liquid cooling device is configured to at least perform liquid cooling on the battery in a non-overcharge state, and the second liquid cooling device is configured to at least perform liquid cooling on the battery in an overcharge state.

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