Battery thermal management method and system

Abstract

The embodiment of the invention discloses a battery thermal management method and system. The method comprises the steps of obtaining a current working state of a battery pack; if the working state is a charging state, determining whether the battery pack is in an overcharge state; if the battery pack is in a non-overcharge state, performing heat exchange control on the top and bottom liquid cooling plates and the battery pack by adopting a first liquid cooling device so as to perform liquid cooling on the battery pack; if the battery pack is in an overcharge state, the second liquid cooling device is adopted to perform heat exchange control on the top and bottom liquid cooling plates and the battery pack so as to perform liquid cooling on the battery pack, so that overhigh temperature and overlarge temperature difference in a battery charging process can be avoided, and particularly, the temperature of the battery in an overcharge process can be ensured to be within a safe range; and the reliability of the battery is ensured.

Description

Technical Field

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

[0002] The Battery Thermal Management System (BTMS) is a vital component of new energy vehicles. Its main function is to form a closed-loop regulation system through heat transfer media, measurement and control units, and temperature control equipment to keep the power battery working 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 safe and efficient operation of the battery system. Summary of the invention

[0003] The present application provides a battery thermal management method and system, which can avoid excessive temperature and excessive temperature difference during battery charging, and especially can ensure that the temperature of the battery is within a safe range during supercharging, 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, which is applied to a battery thermal management system, the battery thermal management system comprising top and bottom liquid cooling plates, a first liquid cooling device and a second liquid cooling device, the first liquid cooling device; the method comprises:

[0005] Get the current working status of the battery pack;

[0006] If the working state is charging state, determine whether the battery pack is in overcharge state;

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

[0008] If the battery pack is in an overcharged state, a second liquid cooling device is used to control heat exchange between the top and bottom liquid cooling plates 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 includes:

[0010] The top and bottom liquid cooling plates are provided with liquid cooling channels, the liquid cooling channels include a first channel opening and a second channel opening, and the top and bottom liquid cooling plates perform heat exchange with the battery;

[0011] A first liquid cooling device, one end of the first liquid cooling device is connected to the first flow channel opening, and the other end of the first liquid cooling device is connected to the second flow channel opening;

[0012] A second liquid cooling device, one end of the second liquid cooling device is connected to the first flow channel opening, and the other end of the second liquid cooling device is connected to the second flow channel opening;

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

[0014] The battery thermal management method provided in the present application includes: obtaining the current working state of the battery pack; if the working state is a charging state, determining whether the battery pack is in a supercharging state; if the battery pack is in a non-supercharging state, using 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 supercharging state, using 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, thereby avoiding excessive temperature and excessive temperature difference during battery charging, and especially ensuring that the temperature of the battery is within a safe range during the supercharging process, thereby ensuring the reliability of the battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0016] Figure 1 A schematic block diagram of a battery thermal management system provided in an embodiment of the present application;

[0017] Figure 2 A schematic flow chart of a battery thermal management method provided in an embodiment of the present application. DETAILED DESCRIPTION

[0018] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

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

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

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

[0022] In addition, in this application, unless otherwise clearly specified or limited in the embodiments, the terms "installed", "connected", "connected" and "fixed" etc. appearing in the embodiments should be understood in a broad sense. For example, the connection can be a fixed connection, a detachable connection, or an integrated connection. It can be understood that it can also be a mechanical connection, an electrical connection, etc.; of course, it can also be a direct connection, or an indirect connection through an intermediate medium, or it can be the internal connection of two elements, or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to the specific implementation situation.

[0023] In related technologies, in order to shorten the charging time of electric vehicles, batteries are usually equipped with fast charging mode and super charging mode (super fast charging mode). When the battery is in fast charging mode, an onboard air conditioning system can be added to the thermal management system to assist in cooling the battery; when the battery is in 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, simply adding an onboard air conditioning system to the thermal management system to assist in cooling the battery cannot reduce the water inlet temperature of the liquid cooling plate to the preset temperature, and its flow rate cannot meet the requirements. As a result, when the battery is in supercharging mode, the battery thermal management system cannot effectively reduce the temperature of the battery, resulting in excessive temperature difference in the battery, which in turn affects the battery life.

[0025] To this end, the present application provides a battery thermal management method and system, which can avoid excessive temperature and excessive temperature difference during battery charging, and especially ensure that the temperature of the battery is within a safe range during overcharging, thereby ensuring the reliability of the battery.

[0026] See also Figure 1 , Figure 1 This is a schematic block diagram of a battery thermal management system provided in an embodiment of the present application. Figure 1 As shown, the present application provides a battery thermal management system, which includes:

[0027] The top and bottom liquid cooling plates 200 are provided with liquid cooling channels, the liquid cooling channels include a first channel opening and a second channel opening, and the top and bottom liquid cooling plates 200 perform heat exchange with the battery 100;

[0028] A first liquid cooling device 300, wherein one end of the first liquid cooling device 300 is connected to the first flow channel opening, and the other end of the first liquid cooling device 300 is connected to the second flow channel opening;

[0029] A second liquid cooling device 400, one end of the second liquid cooling device 400 is connected to the first flow channel opening, and the other end of the second liquid cooling device 400 is connected to the second flow channel opening;

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

[0031] In this embodiment, the first liquid cooling device 300 may be a liquid cooling device for the whole vehicle, that is, the first liquid cooling device 300 may be a liquid cooling device for the electric vehicle; the second liquid cooling device 400 may be a liquid cooling device for a non-whole vehicle, that is, the second liquid cooling device 400 may be a liquid cooling device provided at the 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 quickly 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, thereby ensuring the reliability of the battery 100.

[0032] Meanwhile, a water pump, a heat exchange device and a heater may be provided in the first liquid cooling device 300. Similarly, the second liquid cooling device 400 may also be provided by using 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 by top-bottom liquid cooling. The top-bottom liquid cooling technology achieves efficient temperature control by installing liquid cooling plates on the top and bottom of the battery 100, and using the forced convection of the coolant in the channel to remove heat. Among them, when the first liquid cooling device 300 is used to liquid-cool the battery 100, under normal circumstances, the temperature at the liquid inlet of the top and bottom liquid cooling plates 200 can be 15°C, 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, under normal circumstances, the temperature at the liquid inlet of the top and bottom liquid cooling plates 200 can be 10°C, and the liquid cooling flow rate can be 20L / min.

[0034] It should be noted that the main reason why the second liquid cooling device 400 is added to the thermal management system in this application is that after the battery pack is cooled by top-bottom liquid cooling, the battery 100 is configured with a supercharge mode (4C high-rate charging mode), and then it is found that the top-bottom liquid cooling method cannot control the battery pack temperature and 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 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 instead, and the second liquid cooling device 400 is configured to at least liquid cool the battery 100 in the supercharged state.

[0035] In addition, the non-supercharging state mentioned in the present application may 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 in the present application includes 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 plates 200 are provided with liquid cooling channels, and the liquid cooling channels include a first channel opening and a second channel opening. The top and bottom liquid cooling plates 200 perform heat exchange with the battery 100. One end of the first liquid cooling device 300 is connected to the first channel opening, and the other end of the first liquid cooling device 300 is connected to the second channel opening. One end of the second liquid cooling device 400 is connected to the first channel opening, and the other end of the second liquid cooling device 400 is connected to the second channel opening. The first liquid cooling device 300 is configured to perform liquid cooling on at least the battery 100 in a non-supercharged state, and the second liquid cooling device 400 is configured to perform liquid cooling on at least the battery 100 in a supercharged state, thereby avoiding excessive temperature and excessive temperature difference during charging of the battery 100, and in particular, ensuring that the temperature of the battery 100 is within a safe range during supercharging, thereby ensuring the reliability of the battery 100.

[0037] In some embodiments, Figure 1 As shown, the battery thermal management system also includes a first three-way valve T1 and a second three-way valve T2; wherein, the first end 1 of the first three-way valve T1 is connected to the first flow channel opening, the second end 2 of the first three-way valve T1 is connected to one end of the first liquid cooling device 300, and the third end 3 of the first three-way valve T1 is connected to one end of the second liquid cooling device 400; the first end 1 of the second three-way valve T2 is connected to the other end of the first liquid cooling device 300, the second end 2 of the second three-way valve T2 is connected to the second flow channel opening, and the third end 3 of the second three-way valve T2 is connected to 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 by water path, so that when the battery 100 is in a non-supercharged state, the first liquid cooling device 300 can independently perform liquid cooling on the battery 100, and when the battery 100 is in a supercharged state, the second liquid cooling device 400 can independently perform liquid cooling on the battery 100.

[0039] Specifically, when the battery 100 is in a non-supercharged state, the first end 1 and the third end 3 of the first three-way valve T1 are connected, the first end 1 and the second end 2 of the first three-way valve T1 are not connected, the first end 1 and the second end 2 of the second three-way valve T2 are connected, and the second end 2 and the third end 3 of the second three-way valve T2 are not connected, so that the first liquid cooling device 300 can be used to liquid-cool the battery 100 alone; when the battery 100 is in a supercharged state, the first end 1 and the third end 3 of the first three-way valve T1 are not connected, the first end 1 and the second end 2 of the first three-way valve T1 are connected, the first end 1 and the second end 2 of the second three-way valve T2 are not connected, and the second end 2 and the third end 3 of the second three-way valve T2 are connected, so that the first liquid cooling device 300 can be used to liquid-cool the battery 100 alone. Among them, both the first three-way valve T1 and the second three-way valve T2 can be controlled by the battery 100 management system of the battery pack.

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

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

[0042] The liquid-cooled socket 500 is a charging socket that uses liquid cooling technology and is mainly used in the charging system of electric vehicles. The liquid-cooled socket 500 uses coolant to reduce the temperature during the charging process, thereby improving charging efficiency and safety. The advantage of the liquid-cooled socket 500 is that it can effectively reduce the temperature during the charging process, thereby reducing the demand for cable cross-sectional area, reducing the weight of the plug and cable, and improving operational convenience. In addition, the liquid-cooled socket 500 can also help the charging pile to stably achieve a higher charging power. For example, in high-power charging, the liquid-cooled socket 500 can make the charging power stably reach 500kW, and even reach 700kW in a short period of time.

[0043] In some embodiments, 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 channel includes a first liquid cooling channel and a second liquid cooling channel; wherein, the first liquid cooling channel is arranged in the first liquid cooling plate 201, and the second liquid cooling channel is arranged 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 using a first three-way joint 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 using a second three-way joint T6.

[0044] In this embodiment, the first liquid cooling plate 201 and the second liquid cooling plate 202 can be respectively located on the corresponding two sides of the battery 100. Specifically, the first liquid cooling plate 201 can be arranged at the top of the battery 100, and the second liquid cooling plate 202 can be arranged at the bottom of the battery 100, so that the battery 100 can be liquid-cooled by top-bottom liquid cooling. 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 three-way joint 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 three-way joint T6.

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

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

[0047] In this 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 a better liquid cooling effect. However, this method may result in a better cooling effect on the top of the battery 100 and a poor cooling effect on the bottom of the battery 100, thereby causing a large temperature difference between the top and the bottom.

[0048] For example, if the first liquid cooling plate 201 is a stamped liquid cooling plate and the second liquid cooling plate 202 is an extruded liquid cooling plate, the liquid cooling effect of the stamped liquid cooling plate is better than that of the extruded liquid cooling plate, which will lead to better cooling effect on the top of the battery 100 and poor cooling effect on the bottom of the battery 100, resulting in a large temperature difference between the top and the bottom.

[0049] To this end, the present application needs to set the liquid cooling flow rate of the first liquid cooling channel to be smaller than the liquid cooling flow rate of the second liquid cooling channel. Specifically, the liquid cooling flow rate ratio between the first liquid cooling channel and the second liquid cooling channel can be 3:7.

[0050] Furthermore, in the process of realizing that the liquid cooling flow rate of the first liquid cooling channel is smaller than the liquid cooling flow rate of the second liquid cooling channel, the inner diameter of the first end 1 of the first three-way joint T5 can be set smaller than the inner diameter 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 set smaller than the inner diameter 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 channel can be set to be smaller than the liquid cooling flow rate of the second liquid cooling channel according to actual application, and this application does not make specific restrictions. For example, the first three-way connector T5 and the second three-way interface can be replaced with a three-way valve to achieve.

[0052] In some embodiments, the first liquid cooling plate 201 comprises a stamped liquid cooling plate, and the second liquid cooling plate 202 comprises an extruded liquid cooling plate.

[0053] Specifically, the liquid cooling plate usually configured for the battery pack is a stamped liquid cooling plate. Since the present application adopts a top-bottom liquid cooling method, and the bottom of the stamped liquid cooling plate where the battery 100 is placed cannot be subjected to force, the liquid cooling plate at the bottom of the battery 100 needs to be configured as an extruded liquid cooling plate.

[0054] Stamped liquid cooling plate is a liquid cooling plate manufactured by stamping process, usually used to manufacture cooling plates of simple shapes. Among them, stamped liquid cooling plate has the advantages of arbitrary flow channel design, large contact area, good heat exchange effect, high production efficiency, good pressure resistance and strength. At the same time, during the production process of stamped liquid cooling plate, stamped liquid cooling plate needs to be degreased to remove oil and impurities on the surface to ensure that the stamped liquid cooling plate can perform at its best during use.

[0055] Extruded liquid cooling plate is a product that combines extrusion technology and liquid cooling technology, and is mainly used in situations where efficient heat dissipation and heat preservation are required. Extruded liquid cooling plate can combine the heat preservation performance of extruded plate with the heat dissipation performance of liquid cooling plate, and is used in situations where both efficient heat dissipation and heat preservation are required.

[0056] In some embodiments, the battery thermal management system further includes an exhaust assembly; wherein one end of the exhaust assembly is respectively connected to the first flow channel opening and one end of the first liquid cooling device 300, and the other end of the exhaust assembly is connected to the outside.

[0057] Specifically, the present application may also provide an exhaust assembly at the first flow channel opening to discharge the air in the pipeline, thereby further improving the liquid cooling effect of the top and bottom liquid cooling. Among them, 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 may be provided in the vehicle and used in conjunction with the first liquid cooling device 300, thereby further improving the liquid cooling effect of the first liquid cooling device 300.

[0058] Furthermore, in some embodiments, Figure 1 As shown, the exhaust assembly includes an exhaust pipe and a third three-way valve T3; wherein, the first end 1 of the third three-way valve T3 is connected to the first flow channel outlet, the second end 2 of the third three-way valve T3 is connected to one end of the first liquid cooling device 300, the third end 3 of the third three-way valve T3 is connected to one end of the exhaust pipe, and the other end of the exhaust pipe is connected to the outside.

[0059] In this embodiment, by setting the third three-way valve T3 at the first flow channel opening and one end of the first liquid cooling device 300, when the pipeline needs to be exhausted, the first end 1 and the third end 3 of the third three-way valve T3 can be connected, and when the pipeline does not need to be exhausted, the first end 1 and the second end 2 of the third three-way valve T3 are connected and the first end 1 and the third end 3 of the third three-way valve T3 are not connected.

[0060] Furthermore, in some embodiments, Figure 1 As shown, the exhaust component also includes a liquid injection pot 600 and a fourth three-way valve T4; wherein the liquid injection pot 600 is connected to the first end 1 of the fourth three-way valve T4, the second end 2 of the fourth three-way valve T4 is connected to the second end 2 of the third three-way valve T3, the third end 3 of the fourth three-way valve T4 is connected to one end of the first liquid cooling device 300, and the other end of the exhaust pipe is connected to the outside through the liquid injection pot 600.

[0061] Specifically, the present application may also set a fourth three-way valve T4 between the third three-way valve T3 and the first liquid cooling device 300, and set a liquid filling pot 600 between the third three-way valve T3 and the fourth three-way valve T4, which can not only avoid the reduction of coolant in the pipeline during the exhaust process, but also facilitate the replenishment of liquid in the pipeline.

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

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

[0064] In addition, when the pipeline only needs to be exhausted, only 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. The battery thermal management system described in the embodiment of this application is to more clearly illustrate the technical solution of the embodiment of this application, and does not constitute a limitation on the technical solution provided in the embodiment of this application. It is known to those skilled in the art that with the evolution of the system and the emergence of new business scenarios, the technical solution provided in the embodiment of this application is also applicable to similar technical problems. The following are detailed descriptions.

[0066] It should be noted that the description order of the following embodiments is not intended to limit the preferred order of the embodiments. The thermal management method of the battery thermal management system is described in detail below. At the same time, the thermal management method of the battery thermal management system provided in this application can be executed by the battery management system.

[0067] See also Figure 2 , Figure 2 This is a flow chart of the battery thermal management method provided in the embodiment of the present application. Figure 2 As shown, the method includes steps S110 to S140.

[0068] S110. Obtain the current working status 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 charging and discharging of the battery pack to obtain the current working state of the battery pack. The working state of the battery pack includes the charging state and the discharging state.

[0070] In some embodiments, after step S110, the following steps are also included: if the working state is a discharge state, determining whether the vehicle where the battery pack is located is in a driving state; if the vehicle is in a driving state, using a first liquid cooling device to control heat exchange between the top and bottom liquid cooling plates and the battery pack to liquid-cool the battery pack.

[0071] In this embodiment, the working state of the battery pack also includes a discharge state. Since the battery pack will also generate heat when discharging, the temperature of the battery pack will increase. Therefore, when the present application obtains the current working state of the battery pack and determines that the working state is a discharge state, it is necessary to start the thermal management system to perform thermal management on the battery pack to ensure that the temperature of the battery pack is within a safe range during the discharge process. At the same time, the battery pack mentioned in this application is installed in the vehicle. After determining that the battery pack is in a discharge state, it is also necessary to determine whether the vehicle in which the battery pack is located is in a driving state. If the vehicle is in a driving state, the first liquid cooling state can be used to control the flow rate and temperature of the liquid inlet of the top and bottom liquid cooling plates 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, determine whether the battery pack is in the overcharging state.

[0073] In this embodiment, when the battery pack is in a charging state, it can be in a normal charging state, a fast charging state, or an overcharging state. When the battery pack is in a fast charging state, the heat generated by it is higher than that in a normal charging state. It can 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; when the battery pack is in an overcharging state, the heat generated by it is higher than that in a 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 be guaranteed that the battery pack temperature and temperature difference are within a safe range. Therefore, when determining that the battery pack is in a charging state, the present application also needs to further determine whether the battery pack is in an overcharging state to ensure that the temperature and temperature difference of the battery pack during the charging process are within a safe range.

[0074] S130: If the battery pack is in a non-supercharged state, a first liquid cooling device is used to control heat exchange between the top and bottom liquid cooling plates and the battery pack to liquid-cool the battery pack.

[0075] In this embodiment, the non-supercharge state includes a fast charge state and a normal charge state. When the battery pack is in the non-supercharge state, the first liquid cooling device can be used to control the flow and temperature of the liquid inlets of the top and bottom liquid cooling plates, so that the liquid in the top and bottom liquid cooling plates can fully 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, before using the first liquid cooling device to control the heat exchange between the top and bottom liquid cooling plates and the battery pack, it also includes: obtaining a first liquid cooling temperature at the liquid inlet of the liquid cooling flow channel of the top and bottom liquid cooling plates; if the first liquid cooling temperature is greater than or equal to the preset first temperature, determining whether the first liquid cooling flow at the liquid inlet reaches the preset first flow; if the first liquid cooling flow reaches the first flow, controlling the connection between the first end and the third end of the first three-way valve, and the connection between the second end and the third end of the second three-way valve; using the second liquid cooling device to adjust the first liquid cooling flow at the liquid inlet to a preset second flow; wherein the second flow is greater than the first flow.

[0077] In this embodiment, when the first liquid cooling device is used to control the heat exchange between the top and bottom liquid cooling plates and the battery pack, the temperature of the liquid at the liquid inlet of the top and bottom liquid cooling plates, that is, the first liquid cooling temperature, may be too high due to factors such as the external environment, and may be higher than the preset first temperature, which may be 15°C. At this time, the first liquid cooling device is needed to increase the flow at the liquid inlet, but the flow at the liquid inlet at this time, that is, the first liquid cooling flow, may be the maximum flow that the first liquid cooling device can increase, that is, the first flow. At this time, if the first liquid cooling device is continued to be used to control the heat exchange between the top and bottom liquid cooling plates and the battery pack, it is impossible to ensure that the temperature and temperature difference of the battery pack are within a safe range. The liquid cooling power of the second liquid cooling device is much greater than the liquid cooling power of the first liquid cooling device in this application. Therefore, when it is determined that the first liquid cooling flow reaches the first flow, the first end and the third end of the first three-way valve can be controlled to be connected, and the second end and the third end of the second three-way valve can be controlled to be connected, and the second liquid cooling device can be used to adjust the first liquid cooling flow at the liquid inlet to the preset second flow to ensure that the temperature and temperature difference of the battery pack are within a safe range.

[0078] In some embodiments, after using a second liquid cooling device to adjust the first liquid cooling flow at the liquid inlet to a preset second flow, it also includes: after a preset first time, obtaining a second liquid cooling temperature at the liquid inlet; if the second liquid cooling temperature is less than or equal to the preset second temperature, controlling the connection between the first end and the second end of the first three-way valve, and the connection between the second end and the second end of the second three-way valve; wherein the second temperature is less than the first temperature; using the first liquid cooling device to adjust the liquid cooling flow at the liquid inlet to a preset third flow; wherein the third flow is less than or equal to the first flow.

[0079] In this embodiment, the second temperature may be the first temperature. Since the battery pack is in a 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 plates and the battery pack, it will cause a waste of resources. Therefore, in the process of adjusting the first liquid cooling flow at the liquid inlet to the preset second flow using the second liquid cooling device, the second liquid cooling temperature at the liquid inlet is obtained after the preset first time. If the second liquid cooling temperature is less than or equal to the preset second temperature, the first end and the second end of the first three-way valve are controlled to be connected, as well as the second end and the second end of the second three-way valve are controlled to be connected, and the first liquid cooling device is used to adjust the liquid cooling flow at the liquid inlet to a preset third flow. Among them, the third flow may be less than or equal to the first flow.

[0080] In some embodiments, a first liquid cooling device is used to control heat exchange between the top and bottom liquid cooling plates and the battery pack to liquid-cool the battery pack, including: if the first liquid cooling flow rate does not reach the first flow rate, controlling the connection between the first end and the second end of the first three-way valve, and the connection 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 rate at the liquid inlet to the first flow rate to liquid-cool the battery pack.

[0081] Specifically, the flow at the liquid inlet of the top and bottom liquid cooling plates 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 reached at the liquid inlet can be the first flow. When the first liquid cooling flow does not reach the first flow, the connection between the first end and the second end of the first three-way valve and the connection between the first end and the second end of the second three-way valve can be controlled at this time; the first liquid cooling device is used to increase the first liquid cooling flow at the liquid inlet to the first flow 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 channel of the top and bottom liquid cooling plates, it also includes: if the first liquid cooling temperature is less than or equal to a preset third temperature, controlling the connection between the first end and the second end of the first three-way valve, and the connection between the first end and the second end of the second three-way valve; wherein the third temperature is less than the first temperature; and using a heater in the first liquid cooling device to increase the liquid cooling temperature at the liquid inlet to a preset fourth temperature to heat the battery pack.

[0083] Specifically, during the charging process of the battery pack, the liquid in the pipeline may cause the temperature at the liquid inlet of the top and bottom liquid cooling plates to be too low due to the low external temperature. At this time, the battery pack needs to be heated to charge normally. However, the battery pack provided in the present application does not use a heating film or other device for heating, and a heater is provided in the first liquid cooling device. At this time, when the first liquid cooling temperature is less than or equal to the preset third temperature, the first end and the second end of the first three-way valve can be controlled to be connected, and the first end and the second end of the second three-way valve can be controlled to be connected, and the heater in the first liquid cooling device can be used to increase the liquid cooling temperature at the liquid inlet to the preset fourth temperature to heat the battery pack, thereby ensuring that the battery pack is charged normally.

[0084] That is to say, the heating and cooling of the battery pack mentioned in this application both use top and bottom liquid cooling plates to control the temperature and temperature difference, which reduces the production cost of the battery pack and improves the safety and reliability of the battery pack.

[0085] S140: If the battery pack is in an overcharge state, a second liquid cooling device is used to control heat exchange between the top and bottom liquid cooling plates and the battery pack to liquid-cool the battery pack.

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

[0087] In some embodiments, step S140 includes the following steps: if the battery pack is in a supercharged state, obtaining a third liquid cooling temperature at the liquid inlet of the liquid cooling channel of the top and bottom liquid cooling plates; if the third liquid cooling temperature is greater than or equal to a preset fifth temperature, controlling the connection between the first end and the third end of the first three-way valve, and the connection between the first end and the third end of the second three-way valve; and using a second liquid cooling device to adjust the liquid cooling flow at the liquid inlet to a preset fourth flow 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 the fifth temperature and the sixth temperature. The fifth temperature is greater than the sixth temperature, and the average value between the fifth temperature and the sixth temperature can be 10°C. When the temperature at the liquid inlet of the liquid cooling flow channel of the top and bottom liquid cooling plates, that is, 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, it is necessary to control the connection between the first end and the third end of the first three-way valve, and the connection between the first end and the third end of the second three-way valve, and use the second liquid cooling device to adjust the liquid cooling flow rate at the liquid inlet to the preset fourth flow rate to ensure that the temperature at the liquid inlet is within the preset temperature range, thereby ensuring that the temperature and temperature difference of the battery pack in the overcharge state are within a safe range.

[0089] In some embodiments, after using a second liquid cooling device to adjust the liquid cooling flow at the liquid inlet to a preset fourth flow to liquid cool the battery pack, it also includes: after a preset second time, obtaining 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; wherein the fifth flow is less than or equal to the fourth flow.

[0090] In this embodiment, since the liquid cooling flow rate at the liquid inlet is increased to the fourth flow rate, and the fourth flow rate 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, the temperature at the liquid inlet may be too low. Therefore, after the 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 the preset sixth temperature, the liquid cooling flow rate at the liquid inlet is adjusted to the preset fifth flow rate. Among them, the fifth flow rate can be 20L / 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, it also includes: if an exhaust command from the battery thermal management system is received, controlling the first end and the third end of the third three-way valve to be connected to discharge the gas in the battery thermal management system through the exhaust pipe; if no exhaust command is received, controlling the first end and the second end of the third three-way valve to be connected.

[0092] Specifically, the present application may also provide an exhaust assembly at the first flow channel opening to discharge the air in the pipeline, thereby further improving the cooling effect of the top and bottom liquid cooling. Among them, since the cooling power of the second liquid cooling device is much greater than that of the first liquid cooling device, the exhaust assembly may be provided in the vehicle and used in conjunction with the first liquid cooling device, thereby further improving the cooling effect of the first liquid cooling device.

[0093] In some embodiments, the first end and the third end of the third three-way valve are controlled to be connected so that the gas in the battery thermal management system is discharged from the exhaust pipe, including: controlling the first end and the third end of the third three-way valve to be connected, and the first end and the third end of the fourth three-way valve to be connected, so that the gas in the battery thermal management system is discharged from the exhaust pipe and the liquid injection pot in sequence.

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

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

[0096] Specifically, the present application may also set a fourth three-way valve between the third three-way valve and the first liquid cooling device, and set a liquid filling pot between the third three-way valve and the fourth three-way valve, which can not only avoid the reduction of coolant in the pipeline during the exhaust process, but also facilitate the replenishment of liquid in the pipeline.

[0097] In this embodiment, when only exhaust is required in the pipeline, only the first end and the third end of the third three-way pipe can be connected. When the first liquid cooling device is required to liquid-cool the battery and exhaust is required in the pipeline, the first end and the third end of the third three-way pipe can be connected, and the first end and the second end of the fourth three-way pipe can be connected. The first end and the second end of the third three-way pipe can be connected or not; the second ends of the fourth connecting pipe can be connected or not.

[0098] The battery thermal management method provided in the present application obtains the current working state of the battery pack; if the working state is a charging state, determines whether the battery pack is in a supercharging state; if the battery pack is in a non-supercharging state, uses 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 supercharging state, uses 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, thereby avoiding excessive temperature and excessive temperature difference during battery charging, and especially ensuring that the temperature of the battery is within a safe range during the supercharging process, thereby ensuring the reliability of the battery.

[0099] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any technician familiar with the technical field can easily think of various equivalent modifications or replacements within the technical scope disclosed in the present application, and these modifications or replacements should be included in the protection scope of the present application. Therefore, the protection scope of the present application shall be based on the protection scope of the claims.

Claims

1. A battery thermal management method, characterized in that: Applied to a battery thermal management system, the battery thermal management system includes top and bottom liquid cooling plates, a first liquid cooling device and a second liquid cooling device, the first liquid cooling device; the method includes: Get the current working status of the battery pack; If the working state is a charging state, determining whether the battery pack is in a supercharging state; If the battery pack is in a non-supercharged state, the first liquid cooling device is used to control 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 overcharged state, the second liquid cooling device is used to control the heat exchange between the top and bottom liquid cooling plates and the battery pack to liquid-cool the battery pack.

2. The battery thermal management method according to claim 1, characterized in that: After obtaining the current working status of the battery pack, the method further includes: If the working state is a discharging state, determining whether the vehicle where the battery pack is located is in a driving state; If the vehicle is in a driving state, the first liquid cooling device is used to control the heat exchange between the top and bottom liquid cooling plates and the battery pack to liquid-cool the battery pack.

3. The battery thermal management method according to claim 1, characterized in that: The battery thermal management system further includes a first three-way valve and a second three-way valve; Wherein, before the first liquid cooling device is used to control the heat exchange between the top and bottom liquid cooling plates and the battery pack, the method further includes: Acquiring a first liquid cooling temperature at a liquid inlet of a liquid cooling channel of the top and bottom liquid cooling plates; If the first liquid cooling temperature is greater than or equal to a preset first temperature, determining whether the first liquid cooling flow rate at the liquid inlet reaches a preset first flow rate; If the first liquid cooling flow rate reaches the first flow rate, controlling the first end and the third end of the first three-way valve to be connected, and controlling the second end and the third end of the second three-way valve to be connected; The second liquid cooling device is used to adjust the first liquid cooling flow at the liquid inlet to a preset second flow; wherein the second flow is greater than the first flow.

4. The battery thermal management method according to claim 3, characterized in that: After the second liquid cooling device is used to adjust the first liquid cooling flow rate at the liquid inlet to a preset second flow rate, the method further includes: After a preset first time, obtaining a second liquid cooling temperature at the liquid inlet; If the second liquid cooling temperature is less than or equal to a preset second temperature, controlling the first end and the second end of the first three-way valve to be connected, and the second end and the second end of the second three-way valve to be connected; wherein the second temperature is less than the first temperature; The first liquid cooling device is used to adjust the liquid cooling flow at the liquid inlet to a preset third flow; wherein the third flow is less than or equal to the first flow.

5. The battery thermal management method according to claim 3, characterized in that: The 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 includes: If the first liquid cooling flow rate does not reach the first flow rate, controlling the first end and the second end of the first three-way valve to be connected, and controlling the first end and the second end of the second three-way valve to be connected; The first liquid cooling device is used to increase the first liquid cooling flow rate at the liquid inlet to the first flow rate, so as to liquid-cool the battery pack.

6. The battery thermal management method according to claim 3, characterized in that: After obtaining the first liquid cooling temperature at the liquid inlet of the liquid cooling channel of the top and bottom liquid cooling plates, the method further includes: If the first liquid cooling temperature is less than or equal to a preset third temperature, controlling the first end and the second end of the first three-way valve to be connected, and the first end and the second end of the second three-way valve to be connected; 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 to heat the battery pack.

7. The battery thermal management method according to claim 1, characterized in that: The battery thermal management system further includes a first three-way valve and a second three-way valve; Wherein, if the battery pack is in a supercharged state, the second liquid cooling device is used to control the heat exchange between the top and bottom liquid cooling plates and the battery pack to liquid-cool the battery pack, including: If the battery pack is in a supercharged state, obtaining a third liquid cooling temperature at a liquid inlet of a liquid cooling channel of the top and bottom liquid cooling plates; If the third liquid cooling temperature is greater than or equal to a preset fifth temperature, controlling the first end and the third end of the first three-way valve to be connected, and controlling the first end and the third end of the second three-way valve to be connected; The second liquid cooling device is used to adjust the liquid cooling flow rate at the liquid inlet to a preset fourth flow rate to liquid-cool the battery pack.

8. The battery thermal management method according to claim 7, characterized in that: After the second liquid cooling device is used to adjust the liquid cooling flow rate at the liquid inlet to a preset fourth flow rate to liquid-cool the battery pack, the method further includes: After a preset second time, obtaining 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, 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.

9. The battery thermal management method according to any one of claims 1 to 8, characterized in that: 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 plates and the battery pack to liquid-cool the battery pack, the method further includes: If an exhaust command from the battery thermal management system is received, controlling the first end and the third end of the third three-way valve to be connected so as to exhaust the gas in the battery thermal management system through the exhaust pipe; If the exhaust command is not received, the first end and the second end of the third three-way valve are controlled to be connected.

10. The battery thermal management method according to claim 9, characterized in that: The battery thermal management system also includes a fourth three-way valve and a liquid injection pot; Wherein, controlling the first end and the third end of the third three-way valve to be connected so as to discharge the gas in the battery thermal management system through the exhaust pipe includes: 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, so that the gas in the battery thermal management system is discharged from the exhaust pipe and the liquid injection pot in sequence; Wherein, after controlling the communication between the first end and the second end of the third three-way valve, the method further comprises: Control the communication between the second end and the third end of the fourth three-way valve.

11. A battery thermal management system, characterized in that: include: The top and bottom liquid cooling plates are provided with liquid cooling channels, the liquid cooling channels include a first channel opening and a second channel opening, and the top and bottom liquid cooling plates perform heat exchange with the battery; A first liquid cooling device, wherein one end of the first liquid cooling device is connected to the first flow channel opening, and the other end of the first liquid cooling device is connected to the second flow channel opening; a second liquid cooling device, wherein one end of the second liquid cooling device is connected to the first flow channel opening, and the other end of the second liquid cooling device is connected to the second flow channel opening; The first liquid cooling device is configured to at least perform liquid cooling on the battery in a non-supercharged state, and the second liquid cooling device is configured to at least perform liquid cooling on the battery in a supercharged state.

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