A method, management device and system for battery pack charge-discharge thermal management

Abstract

This invention provides a method, device, and system for thermal management of battery pack charging and discharging, belonging to the field of lithium-ion batteries. The method defines the allowable charging and discharging temperatures as including an ultra-low temperature operating range, a low temperature operating range, and a normal operating range. Within the ultra-low temperature operating range, the temperature is first raised to the low temperature operating range using a liquid heating device, and then a heating film is activated for further heating. Once the temperature stabilizes within the normal operating range, the battery pack is then allowed to begin discharging or charging. This method has wide applicability and strong practicality, broadening the temperature range for battery pack charging and discharging thermal management applications. It provides a solution for effective thermal management under ultra-low temperature conditions, avoiding uneven heating of the cells under ultra-low temperature conditions that affects charging and discharging performance and cell lifespan, thus contributing to extending the service life of the battery system.

Description

Technical Field

[0001] This invention belongs to the field of batteries and relates to a method, management device and system for thermal management of battery pack charging and discharging. Background Technology

[0002] Currently, with the rapid development of the new energy industry, new energy vehicles are gradually replacing traditional fuel vehicles and becoming people's means of transportation. However, due to the inherent charging and discharging characteristics of lithium batteries, the performance of the entire battery system varies under different temperature conditions. Especially in extreme seasons such as winter and summer, reasonable thermal management strategies are needed for the battery pack to adapt its charging and discharging behavior to different usage environments and improve the user experience.

[0003] CN110931896A provides a lithium-ion battery temperature management system, including a battery management system, a temperature control module, and an information acquisition module. The information acquisition module collects the temperature of the battery module and each lithium battery within it, and feeds this temperature data back to the battery management system. The battery management system determines whether each temperature exceeds 35°C based on the temperature data from the information acquisition module. If the temperature exceeds 35°C, it controls the cooling system to cool the corresponding lithium battery. The battery management system also determines whether each temperature is below 5°C based on the temperature data from the information acquisition module. If the temperature is below 5°C, it controls the heating device to heat the corresponding lithium battery. Therefore, this system can maintain the operating temperature of the lithium-ion battery within a consistent range, thereby improving the safety of the lithium battery during operation.

[0004] This solution can achieve thermal management in certain low-temperature or high-temperature environments, but it does not provide applicable strategies for extreme low-temperature environments (such as -15 to -30℃). This is because the existing technology uses a single heating film for heating during the heating process, such as the heating film and battery module using the heating film disclosed in CN113764780A. This heating solution can easily cause excessive local temperature differences in the battery pack due to the drawbacks of constant heating film power and uneven heating in extreme low-temperature environments, resulting in uneven heating of the battery cells and seriously affecting the battery cell life.

[0005] It can be seen that the battery and the auxiliary thermal management equipment support each other. Therefore, it is necessary to analyze different temperature environments, internal and external power supply conditions and other factors based on the actual situation, and to provide a new battery pack charging and discharging thermal management solution for a wider range of actual operations, including extreme temperatures. Summary of the Invention

[0006] In view of the problems existing in the prior art, the purpose of this invention is to provide a method, management device, and system for battery pack charge and discharge thermal management. The method includes an ultra-low temperature operating range, a low temperature operating range, and a normal operating range for the allowable charge and discharge temperatures. Within the ultra-low temperature operating range, the temperature is first raised to the low temperature operating range using a liquid heating device, and then a heating film is activated for further heating. Once the temperature stabilizes within the normal operating range, the battery pack is then allowed to begin discharging or charging. This method has wide applicability and strong practicality, broadening the temperature range for battery pack charge and discharge thermal management applications. It provides a solution for effective thermal management under ultra-low temperature conditions, avoiding uneven heating of the cells under ultra-low temperature conditions that affects charge and discharge performance and cell lifespan, thus helping to extend the service life of the battery system.

[0007] To achieve this objective, the present invention adopts the following technical solution:

[0008] In a first aspect, the present invention provides a method for thermal management of a battery pack during charging and discharging, the method comprising:

[0009] Set the allowable temperature range for discharge or charge [T1, T4], which includes the ultra-low temperature operating range [T1, T2], the low temperature operating range (T2, T3) and the normal operating range (T3, T4). Monitor and determine the temperature of the battery pack, and discharge or charge it in the following manner:

[0010] The initial temperature of the battery pack is t1, and the real-time temperature of the battery pack after heating or cooling is t.

[0011] When T1≤t1≤T2, the liquid heating device is turned on to heat the battery pack. When T2<t≤T3, the heating film is turned on to heat the battery pack together. When T3<t≤T4, the liquid heating device and the heating film are turned off, and the battery pack begins to discharge or charge.

[0012] This invention, when operating within the ultra-low temperature range, first activates the liquid heating device to raise the temperature until it reaches the specified low-temperature operating range. Then, it activates the heating film for further heating until the temperature reaches the normal operating range. Finally, it shuts off the liquid heating device and the heating film, allowing the battery pack to begin discharging or charging. This results in more uniform heating and heat transfer during battery heating or cooling, preventing uneven heating of the cells from affecting charge / discharge performance and cell lifespan, and ultimately extending the lifespan of the battery system. Specifically, when operating in ultra-low temperatures, directly using a heating film for heating has drawbacks such as constant power and uneven heating. Although it can quickly increase the cell temperature, it causes excessive local temperature differences within the battery pack, resulting in uneven heating of the cells and severely affecting cell lifespan. The method described in this invention first uses a liquid-thermal device for heating. Although its heating rate is lower than that of the heating film, it ensures uniform heating of the cells, which is beneficial for improving the activity of the internal chemical materials of the cells. Once the temperature rises to the low-temperature operating range, the heating film is then activated. This dual heating method rapidly increases the cell temperature, bringing it into a reasonable charge-discharge range (the conventional operating range), which helps extend the system's lifespan.

[0013] The temperature of the battery pack described in this invention is the lowest temperature of the busbar or the average temperature of multiple busbars. Alternatively, it can be selected as other types of temperature data within the battery pack, depending on the actual situation.

[0014] The following are preferred technical solutions of the present invention, but are not intended to limit the technical solutions provided by the present invention. The technical objectives and beneficial effects of the present invention can be better achieved and realized through the following technical solutions.

[0015] As a preferred technical solution of the present invention, the method further includes setting a first target temperature T6, where T2 < T6 ≤ T3, monitoring and judging the temperature of the battery pack, turning on the liquid heat device to heat the battery pack when T1 ≤ t1 ≤ T2, turning on the heating film to heat the battery pack together when T6 ≤ t ≤ T3, turning off the liquid heat device and the heating film when T3 < t ≤ T4, and the battery pack begins to discharge or charge.

[0016] Preferably, the difference between T6 and T2 is 5 to 15°C, for example, 5°C, 6°C, 7°C, 8°C, 9°C, 10°C, 11°C, 12°C, 13°C, 15°C or 15°C, but it is not limited to the listed values. Other unlisted values ​​within the above range are also applicable.

[0017] The second target temperature T6 should have a sufficient interval with the minimum temperature in the low-temperature operating range and the maximum temperature T2 in the ultra-low-temperature operating range. When the temperature is raised to the low-temperature operating range using liquid heating and then the liquid heating device is stopped, the temperature will rebound to some extent. If the gap between T6 and T2 is small, the temperature is likely to rebound directly back to the ultra-low-temperature operating range. This will lead to frequent opening and closing of the liquid heating device and affect the life of the unit. Therefore, setting T6 higher allows the liquid heating device to work at full power, thereby improving heating efficiency.

[0018] Preferably, the method further includes monitoring and determining the temperature of the battery pack; when T2 < t1 ≤ T3, turning on the heating film to heat the battery pack; until T3 < t ≤ T4, turning off the heating film, and the battery pack begins to discharge or charge.

[0019] Preferably, the method further includes setting a second target temperature T7, where T3 < T7 ≤ T4, monitoring and determining the temperature of the battery pack, and when T2 < t1 ≤ T3, turning on the heating film to heat the battery pack until T7 ≤ t ≤ T4, turning off the heating film, and the battery pack begins to discharge or charge.

[0020] Preferably, the difference between T7 and T3 is 10 to 15°C, such as 10°C, 10.5°C, 11°C, 11.5°C, 12°C, 12.5°C, 13°C, 13.5°C, 14°C, 14.5°C or 15°C, but it is not limited to the listed values. Other unlisted values ​​within the above range are also applicable.

[0021] The second target temperature T7 should have a sufficient gap from the minimum temperature in the normal operating range and the maximum temperature in the low-temperature operating range T3. When the temperature is raised to the normal operating range by using a heating film and then the heating film is stopped, the temperature will rebound to some extent. If the gap between T7 and T3 is small, the temperature is likely to rebound directly back to the low-temperature operating range. This will lead to frequent opening and closing of the heating film and affect the life of the unit. Therefore, setting T7 higher allows the heating film to work at full power, thereby improving heating efficiency.

[0022] Preferably, the method further includes monitoring and determining the temperature of the battery pack, and when T3 < t1 ≤ T4, directly starting the battery pack to discharge or charge.

[0023] Preferably, the allowable temperature range for the discharge is [-30℃, 35℃].

[0024] Preferably, the allowable temperature range for charging is [-40℃, 35℃].

[0025] Preferably, the cryogenic operating range of the discharge is [-30℃, -15℃].

[0026] Preferably, the ultra-low temperature operating range of the charging is [-40℃, -15℃].

[0027] Preferably, the low-temperature operating range for both discharging and charging is (-15℃, 0℃).

[0028] Preferably, the normal operating range for both discharging and charging is (0℃, 35℃).

[0029] As a preferred technical solution of the present invention, the allowable temperature range is [T1, T5], where T4 < T5. In this case, the allowable temperature range also includes the high-temperature operating range (T4, T5).

[0030] Preferably, the method further includes monitoring and determining the temperature of the battery pack, and when T4 < t1 ≤ T5, turning on the liquid cooling device to cool the battery pack, until T3 < t ≤ T4, turning off the liquid cooling device, and the battery pack begins to discharge or charge.

[0031] Preferably, the method further includes setting a third target temperature T8, where T3 < T8 < T4, monitoring and determining the temperature of the battery pack, and when T4 < t1 ≤ T5, turning on the liquid cooling device to cool the battery pack until T3 < t ≤ T8, turning off the liquid cooling device, and the battery pack begins to discharge or charge.

[0032] Preferably, the difference between T4 and T8 is 10 to 15°C, such as 10°C, 10.5°C, 11°C, 11.5°C, 12°C, 12.5°C, 13°C, 13.5°C, 14°C, 14.5°C, or 15°C, but it is not limited to the listed values. Other unlisted values ​​within the above range are also applicable.

[0033] The third target temperature T8 should have a sufficient interval between the maximum temperature in the normal operating range and the minimum temperature in the high-temperature operating range T4. This is because when liquid cooling is used to reduce the temperature to the normal operating range and then liquid cooling is stopped, the temperature will rebound to some extent. If the gap between T8 and T4 is small, the temperature is likely to rebound directly back to the high-temperature operating range. This will lead to frequent on and off of the liquid cooling device, which will affect the life of the unit. Therefore, setting T8 lower allows the liquid cooling device to work at full power, thereby improving cooling efficiency.

[0034] Preferably, the high-temperature operating range for both discharging and charging is (35℃, 55℃).

[0035] Preferably, the allowable temperature range for the discharge is [-30℃, 55℃].

[0036] Preferably, the allowable temperature range for charging is [-40℃, 55℃].

[0037] It should be noted that the allowable temperature range for discharge or charging described in this invention is determined based on the season and / or geographical environment of the battery. The high-temperature operating range corresponds to high-temperature environments such as summer. Although the battery system can discharge normally at this temperature, considering the heat generated after the battery discharges, liquid cooling is necessary within this temperature range. The normal operating range corresponds to the range from above zero degrees Celsius to near room temperature, at which point the battery can perform normal charging and discharging behavior. The low-temperature operating range corresponds to low-temperature environments in winter, and the ultra-low-temperature operating range corresponds to extremely cold weather or geographical environments.

[0038] Furthermore, the present invention also requires setting different allowable temperature ranges according to the charging and discharging conditions: since the auxiliary heat control devices of the battery pack, such as heating films and liquid heat devices, can be powered by the battery pack itself during the discharge condition, the minimum allowable temperature range for discharge cannot be too low; since the thermal management auxiliary unit of the battery pack can be powered not only by the battery itself but also by external power during the charging condition, the minimum allowable temperature range for charging can be even lower, thereby broadening the temperature range in which the method described in the present invention is applied.

[0039] For example, the minimum value T1 of the ultra-low temperature operating range can be selected within the range of [-40℃, -20℃], such as -40℃, -38℃, -36℃, -34℃, -32℃, -30℃, -28℃, -26℃, -24℃, -22℃, or -20℃; the maximum value of the ultra-low temperature operating range and the minimum value T2 of the low temperature operating range can be selected within the range of [-20℃, -0℃], such as -20℃, -18℃, -16℃, -14℃, -12℃, -10℃, -8℃, -6℃, -4℃, -2℃, or -0℃; the maximum value of the low temperature operating range and the minimum value T3 of the normal temperature operating range can be selected within the range of [-5℃, 15℃]. The values ​​can be selected, for example, -5℃, -3℃, -1℃, 0℃, 1℃, 3℃, 5℃, 7℃, 9℃, 11℃, 13℃, or 15℃, etc.; the maximum value of the normal temperature operating range and the minimum value of the high temperature operating range, T4, can be selected within [30℃, 45℃], for example, 30℃, 33℃, 36℃, 39℃, 42℃, or 45℃, etc.; the maximum value of the high temperature operating range, T5, can be selected within [40℃, 55℃], for example, 40℃, 43℃, 46℃, 49℃, 52℃, or 55℃, etc.; however, it is not limited to the listed values, other unlisted values ​​within the above range are also applicable, and T1 < T2 < T3 < T4 < T5 should be maintained.

[0040] As a preferred technical solution of the present invention, the method includes the following steps:

[0041] S1 When the battery pack receives a discharge or charge signal, it performs a self-test; if a fault is found, the process is stopped and fault information is fed back; if no fault is found, the allowable temperature range for discharge or charge is set [T1,T5], which includes the ultra-low temperature operating range [T1,T2], the low temperature operating range (T2,T3], the normal operating range (T3,T4] and the high temperature operating range (T4,T5]), and then proceeds to step S2.

[0042] S2 monitors and determines whether the battery pack temperature t1 is within the allowable temperature range [T1,T5]: if t1 < T1 or t1 > T5, the process stops and a failure message is returned; if T1 ≤ t1 ≤ T5, proceed to step S3.

[0043] S3 monitors and determines whether the battery pack temperature t1 is within the high-temperature operating range (T4, T5): If T4 < t1 ≤ T5, a third target temperature T8 is set, T3 < T8 < T4, and the liquid cooling device is turned on to cool the battery pack until T3 < t ≤ T8. Then the liquid cooling device is turned off, and the battery pack begins to discharge or charge. If t1 ≤ T4, then step S4 is performed directly.

[0044] S4 monitors and determines whether the battery pack temperature t1 is within the normal operating range (T3, T4): if T3 < t1 ≤ T4, then discharge or charge; if t1 ≤ T3, then proceed directly to step S5.

[0045] S5 monitors and determines whether the battery pack temperature t1 is within the low-temperature operating range (T2, T3): If T2 < t1 ≤ T3, a second target temperature T7 is set, T3 < T7 ≤ T4, and the heating film is turned on to heat the battery pack until T7 ≤ t ≤ T4. Then the heating film is turned off, and the battery pack begins to discharge or charge. If t1 ≤ T2, then proceed directly to step S6.

[0046] S6 monitors and determines whether the battery pack temperature t1 is within the ultra-low temperature operating range [T1,T2]: If T1≤t1≤T2, set the first target temperature T6; if T2<T6≤T3, set the second target temperature T7; if T3<T7≤T4, turn on the liquid heat treatment device to heat the battery pack until T6≤t≤T3, then turn on the heating film to heat the battery pack together until T7≤t≤T4, then turn off the liquid heat treatment device and the heating film, and the battery pack begins to discharge or charge.

[0047] The present invention further divides the allowable temperature range into four different temperature conditions and matches them with corresponding heat control measures, making the method applicable to thermal management in both high-temperature and ultra-low-temperature conditions. Therefore, the method has wide adaptability and strong practicality.

[0048] As a preferred technical solution of the present invention, when the discharge requirement is met in step S4, step S5 or step S6, a pre-charge test is performed first. If the pre-charge test passes, the discharge begins. If the pre-charge test fails, the process is stopped and the pre-charge test failure information is fed back.

[0049] Preferably, the pre-charge detection includes detecting the voltage of the external electrical equipment.

[0050] Preferably, the pre-charge test passing criteria include the voltage of the external electrical equipment reaching 90% or more of the battery pack's system voltage.

[0051] This invention provides pre-charge protection for the entire electrical circuit by performing pre-charge detection before discharge.

[0052] In a second aspect, the present invention provides a management device for battery pack charging and discharging thermal management. The management device is used to implement the method described in the first aspect. The management device includes a temperature acquisition unit, a judgment unit, and a control unit that are electrically connected in sequence. The control unit is electrically connected to both the liquid thermal device and the heating film.

[0053] The temperature acquisition unit is used to acquire the temperature of the battery pack and feed it back to the judgment unit. When the judgment unit determines that T1≤t1≤T2, the control unit controls the liquid heat device to turn on to heat the battery pack. When the judgment unit determines that T2<t≤T3, the control unit controls the heating film to turn on to heat the battery pack together. When the judgment unit determines that T3<t≤T4, the control unit controls the liquid heat device and the heating film to turn off, and the control unit controls the battery pack to start discharging or charging.

[0054] As a preferred technical solution of the present invention, when the judgment unit determines that T1≤t1≤T2, the control unit controls the liquid heat device to heat the battery pack. Until the judgment unit determines that T6≤t≤T3, the control unit controls the heating film to open and heat the battery pack together. Until the judgment unit determines that T3<t≤T4, the control unit controls the liquid heat device and the heating film to close, and the control unit controls the battery pack to start discharging or charging.

[0055] Preferably, when the judgment unit determines that T2 < t1 ≤ T3, the control unit controls the heating film to heat the battery pack until the judgment unit determines that T3 < t ≤ T4, the control unit controls the heating film to turn off, and the control unit controls the battery pack to start discharging or charging.

[0056] Preferably, when the judgment unit determines that T2 < t1 ≤ T3, the control unit controls the heating film to heat the battery pack until the judgment unit determines that T7 ≤ t ≤ T4, the control unit controls the heating film to turn off, and the control unit controls the battery pack to start discharging or charging.

[0057] Preferably, when the judgment unit determines that T3 < t1 ≤ T4, the control unit directly controls the battery pack to start discharging or charging.

[0058] Preferably, the management device (5) further includes a voltage acquisition unit and a current acquisition unit, both of which are electrically connected to the judgment unit.

[0059] Preferably, the determination unit includes a CAN communication module.

[0060] Preferably, the control unit includes a relay control module.

[0061] As a preferred embodiment of the present invention, the control unit is also electrically connected to a liquid cooling device.

[0062] Preferably, the temperature acquisition unit is used to acquire the temperature of the battery pack and feed it back to the judgment unit. When the judgment unit determines that T4 < t1 ≤ T5, the control unit controls the liquid cooling device to turn on to cool the battery pack. Until the judgment unit determines that T3 < t ≤ T4, the control unit controls the liquid cooling device to turn off, and the control unit controls the battery pack to start discharging or charging.

[0063] Preferably, when the judgment unit determines that T4 < t1 ≤ T5, the control unit controls the liquid cooling device to turn on to cool the battery pack, until the judgment unit determines that T3 < t ≤ T8, the control unit controls the liquid cooling device to turn off, and the control unit controls the battery pack to start discharging or charging.

[0064] Thirdly, the present invention provides a system for thermal management of battery pack charging and discharging, the system comprising a high-voltage device and the management device described in the second aspect;

[0065] The high-voltage device is equipped with positive and negative interfaces and positive and negative circuits corresponding to the battery pack, external electrical equipment, external charging equipment, liquid heat device and heating film respectively;

[0066] The control unit in the management device is electrically connected to the liquid heat device and the heating film through the high-pressure device.

[0067] The system described in this invention refers to an equipment system, device system, or production device.

[0068] As a preferred technical solution of the present invention, the high-voltage device is provided with an input total positive terminal interface and an input total negative terminal interface corresponding to the total positive output terminal and the total negative output terminal of the battery pack, a discharge output positive terminal interface and a discharge output negative terminal interface for connecting the external electrical equipment, a charging input positive terminal interface and a charging input negative terminal interface for connecting the external charging equipment, and a liquid heat output positive terminal interface and a liquid heat output negative terminal interface, a heating film output positive terminal interface and a heating film output negative terminal interface for supplying power to the heating film and the liquid heat device, respectively.

[0069] The main input positive terminal interface is electrically connected to the discharge output positive terminal interface to form the positive main circuit. The charging input positive terminal interface, the liquid thermal output positive terminal interface and the heating film output positive terminal interface are respectively connected to the positive main circuit to form the charging positive terminal branch, the liquid thermal positive terminal branch and the heating film positive terminal branch.

[0070] The input main negative terminal interface is electrically connected to the discharge output negative terminal interface to form the negative main circuit. The charging input negative terminal interface, the heating film output negative terminal interface and the liquid heat output negative terminal interface are respectively connected to the negative main circuit to form the charging negative terminal branch, the liquid heat negative terminal branch and the heating film negative terminal branch.

[0071] Preferably, a main positive relay is provided on the positive main circuit to control the opening and closing of the positive main circuit.

[0072] Preferably, a manual maintenance switch is provided between the main positive input interface and the main positive relay on the positive main circuit.

[0073] The manual maintenance switch (MSD) contains a fuse that protects the circuit when the battery pack is in operation. When the battery pack needs to be disassembled for maintenance, the fuse can be removed, putting the entire circuit in an open state and protecting the safety of maintenance personnel.

[0074] Preferably, on the positive main line, a discharge relay is provided between the main positive relay and the discharge output positive interface to control the opening and closing of the battery pack discharge behavior.

[0075] Preferably, the charging negative electrode branch, the liquid-thermal negative electrode branch, and the heating film negative electrode branch positive electrode branch are all connected between the main positive relay and the discharge relay.

[0076] Preferably, a pre-charge detection branch is connected in parallel across the two ends of the discharge relay for pre-charge detection before the battery pack is discharged.

[0077] Preferably, a precharge resistor and a precharge relay connected in series are provided on the precharge detection branch.

[0078] Preferably, the charging positive electrode branch, the liquid-thermal positive electrode branch, and the heating film positive electrode branch are provided with corresponding charging relays, liquid-thermal relays, and heating film relays to control the opening and closing of the corresponding positive electrode branches.

[0079] Preferably, a main negative relay is provided on the negative main circuit to control the opening and closing of the negative main circuit.

[0080] Preferably, each negative branch is connected between the main negative relay and the discharge output negative interface.

[0081] Preferably, a shunt is provided between the input main negative terminal interface and the main negative relay on the negative main line.

[0082] The shunt is used to detect the main circuit current.

[0083] Preferably, each of the heating film negative electrode branch and the liquid heat negative electrode branch is provided with a corresponding heating film safety device and a liquid heat safety device.

[0084] The present invention does not impose specific restrictions on the selection of the safety device; for example, a fuse can be selected.

[0085] Preferably, both the heating film negative electrode branch and the liquid thermal negative electrode branch are first connected to the Hall sensor, and then connected to the negative electrode main circuit.

[0086] This invention incorporates a Hall sensor to determine the current during heating, thereby detecting whether the heating function is functioning correctly and preventing open-circuit heating issues.

[0087] Preferably, the high-voltage device is further provided with a liquid-cooled output positive terminal interface and a liquid-cooled output negative terminal interface corresponding to the liquid-cooling device. The liquid-cooled output positive terminal interface is electrically connected to the input main positive terminal interface to form a liquid-cooled positive terminal branch, and the liquid-cooled output negative terminal interface is electrically connected to the input main negative terminal interface to form a liquid-cooled negative terminal branch.

[0088] Preferably, the liquid-cooled positive electrode branch is connected between the main positive relay and the discharge relay.

[0089] Preferably, a liquid-cooled relay is provided on the liquid-cooled positive electrode branch.

[0090] Preferably, the liquid-cooled negative electrode branch is connected between the main negative relay and the discharge output negative electrode interface.

[0091] Preferably, a liquid-cooled safety device is provided on the liquid-cooled negative electrode branch.

[0092] Compared with existing technical solutions, the present invention has at least the following beneficial effects:

[0093] (1) In the ultra-low temperature working range, the present invention first turns on the liquid heat device to raise the temperature until the temperature rises to the low temperature working range, and then turns on the heating film to raise the temperature together until the temperature rises to the normal working range. Then the liquid heat device and the heating film are turned off, and the battery pack is then allowed to start discharging or charging. This makes the battery more uniformly heated and transferred during heating or cooling, avoiding uneven heating of the cells which affects the charging and discharging performance and cell life, and helps to extend the service life of the battery system.

[0094] (2) The method of the present invention further expands the application temperature range of the method by matching the best auxiliary heat control means in four different temperature conditions, making it applicable to both high temperature and ultra-low temperature conditions for heat management. Therefore, the method has wide adaptability and strong practicality.

[0095] (3) A pre-charge detection branch is set in the high-voltage device of the system to perform pre-charge detection before discharge, so as to provide pre-charge protection for the entire electrical circuit; Hall sensors are also set in the liquid heat negative electrode branch and the heating film negative electrode branch of the high-voltage device to detect the current during heating, so as to detect whether the heating function is turned on and prevent faults such as open circuit without heating. Attached Figure Description

[0096] Figure 1 This is a schematic diagram of the battery pack charging and discharging thermal management system described in Embodiment 1 of the present invention;

[0097] Figure 2 This is a flowchart of the battery pack discharge thermal management method described in Example 1 of the present invention;

[0098] Figure 3 This is a flowchart of the battery pack charging thermal management method described in Example 2 of the present invention;

[0099] In the diagram: 1-High voltage device, 111-Input main positive interface, 112-Input main negative interface, 121-Discharge output positive interface, 122-Discharge output negative interface, 131-Charging input positive interface, 132-Charging input negative interface, 141-Liquid-cooled output positive interface, 142-Liquid-cooled output negative interface, 151-Liquid-thermal output positive interface, 152-Liquid-thermal output negative interface, 161-Heating film output positive interface, 162-Heating film output... 21-Negative terminal output, 22-Total positive relay, 23-Discharge relay, 241-Pre-charge relay, 242-Pre-charge resistor, 25-Charging relay, 26-Liquid-cooled relay, 27-Liquid-thermal relay, 28-Heating film relay, 31-Liquid-cooled fuse, 32-Liquid-thermal fuse, 33-Heating film fuse, 41-Manual maintenance switch, 42-Hall sensor, 43-Shunting device, 5-Management device, 6-Auxiliary unit. Detailed Implementation

[0100] The technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be considered as specific limitations thereof.

[0101] Example 1

[0102] This embodiment provides a battery pack charging and discharging thermal management system, such as... Figure 1 As shown, the system includes a high-voltage device 1 and a management device 5;

[0103] The management device 5 includes a temperature acquisition unit, a judgment unit, and a control unit electrically connected in sequence; the judgment unit is also electrically connected to a voltage acquisition unit and a current acquisition unit; the judgment unit includes a CAN communication (Controller Area Network) module; the control unit includes a relay control module; the control unit is electrically connected to the liquid heating device, liquid cooling device, and heating film in the auxiliary unit 6; the temperature acquisition unit is used to acquire the temperature of the battery pack and feed back the signal to the judgment unit; the judgment unit is used to determine the temperature range of the battery pack and transmit the command to the control unit; the control unit is used to turn the liquid heating device, liquid cooling device, and heating film on and off.

[0104] The high-voltage device 1 is used to control the opening and closing of the battery pack's discharge or charging, and to control the opening and closing of the liquid cooling device, the heating film, and the liquid thermal device;

[0105] Specifically, the high-voltage device 1 is provided with an input total positive terminal interface 111 and an input total negative terminal interface 112 corresponding to the total positive output terminal and the total negative output terminal of the battery pack, a discharge output positive terminal interface 121 and a discharge output negative terminal interface 122 for connecting the external electrical equipment, a charging input positive terminal interface 131 and a charging input negative terminal interface 132 for connecting the external charging equipment, and a liquid cooling output positive terminal interface 141 and a liquid cooling output negative terminal interface 142, a liquid heating output positive terminal interface 151 and a liquid heating output negative terminal interface 152, a heating film output positive terminal interface 161 and a heating film output negative terminal interface 162 respectively for supplying power to the liquid cooling device, the heating film and the liquid heat device;

[0106] The main positive input interface 111 is electrically connected to the positive output interface 121 to form the main positive circuit. The positive input interface 131, the liquid-cooled positive output interface 141, the liquid-thermal positive output interface 151, and the positive output interface 161 are respectively connected to the main positive circuit to form corresponding positive charging branch, positive liquid cooling branch, positive liquid thermal branch, and positive heating film branch.

[0107] A main positive relay 21 is provided on the positive main line to control the opening and closing of the positive main line; a manual maintenance switch 41 is provided between the input main positive interface 111 and the main positive relay 21 on the positive main line; a discharge relay 23 is provided between the main positive relay 21 and the discharge output positive interface 121 to control the opening and closing of the battery pack discharge behavior; a pre-charge detection branch is connected in parallel across the two ends of the discharge relay 23 for pre-charge detection before the battery pack discharges; a pre-charge resistor 242 and a pre-charge relay 241 are connected in series on the pre-charge detection branch; each positive branch is provided with a corresponding relay to control the opening and closing of the corresponding positive branch, that is, a charging relay 25 is provided on the charging positive branch, a liquid cooling relay 26 is provided on the liquid cooling positive branch, a liquid heating relay 27 is provided on the liquid heating positive branch, and a heating film relay 28 is provided on the heating film positive branch;

[0108] The input main negative terminal interface 112 is electrically connected to the discharge output negative terminal interface 122 to form the negative main circuit. The charging input negative terminal interface 132, the liquid-cooled output negative terminal interface 142, the liquid-heated output negative terminal interface 152 and the heating film output negative terminal interface 162 are respectively connected to the negative main circuit to form corresponding charging negative terminal branch, liquid-cooled negative terminal branch, liquid-heated negative terminal branch and heating film negative terminal branch.

[0109] A main negative relay 22 is provided on the negative main circuit to control the opening and closing of the negative main circuit. Each negative branch is connected between the main negative relay 22 and the discharge output negative interface 122. A shunt 43 is provided between the input main negative interface 112 and the main negative relay 22 on the negative main circuit. In the negative branches, the liquid-cooled negative branch, the liquid-heated negative branch, and the heating film negative branch are each provided with a corresponding liquid-cooled fuse 31, a liquid-heated fuse 32, and a heating film fuse 33, all of which are fuses. The heating film negative branch and the hot negative branch are both connected to the negative main circuit through the same Hall sensor 42.

[0110] Application Example 1

[0111] This application example provides a method for battery pack discharge thermal management. The method uses the system provided in Example 1, and the flowchart of the method is as follows: Figure 2 As shown, the method includes the following steps:

[0112] S1 sends a start signal to the management device 5. When the battery pack receives a discharge signal, it performs a self-test (including using the voltage acquisition unit and current acquisition unit in the management device 5 to detect the voltage and current of each cell in the battery pack) and feeds back a signal to the judgment unit. If the judgment unit determines that there is a fault, it stops the process, sends a start failure signal, and feeds back the fault information. If it determines that there is no fault, it sets the allowable temperature range for discharge [-30℃, 55℃]. The allowable temperature range includes the ultra-low temperature operating range [-30℃, -15℃], the low temperature operating range (-15℃, 0℃), the normal operating range (0℃, 35℃) and the high temperature operating range (35℃, 55℃). It also transmits a command to the relay control module to close the main negative relay 22 and proceeds to step S2.

[0113] The opening and closing of each relay in the following steps are achieved by transmitting instructions from the judgment unit to the relay control module. To save space, these will not be described in detail.

[0114] The temperature acquisition unit in the S2 management device 5 acquires the temperature of the battery pack. The initial temperature of the battery pack is t1, and the real-time temperature of the battery pack after heating or cooling is t. The unit then sends a signal back to the judgment unit, which determines whether the temperature t1 of the battery pack is within the allowable temperature range [-30℃, 55℃]. If t1 < -30℃ or t1 > 55℃, the process is stopped, a failure message is fed back, and the main negative relay 22 is disconnected after 3 seconds. If -30℃ ≤ t1 ≤ 55℃, the main positive relay 21 is closed, and step S3 is performed.

[0115] The temperature of the battery pack in the following steps is collected by the temperature acquisition unit in the management device 5 and fed back to the judgment unit to determine the temperature range in which t is located. To save space, it will not be described in detail.

[0116] S3 monitors and determines whether the battery pack temperature t1 is within the high-temperature operating range (35℃, 55℃): If 35℃ < t1 ≤ 55℃, the third target temperature is set to 20℃, the liquid cooling relay 26 is closed, the liquid cooling device is turned on, and the battery pack is cooled down until 0℃ < t ≤ 20℃. Then, the liquid cooling relay 26 is opened, the liquid cooling device is turned off, and the pre-charge relay 241 is closed to perform a pre-charge test. When the management device 5 detects that the voltage of the external electrical equipment reaches 90% of the battery pack's system voltage, the pre-charge test is considered to have passed by default. The discharge relay 23 is closed, and the pre-charge relay 241 is opened after 3 seconds, and the system enters the discharge state. If the pre-charge test fails, the pre-charge relay 241 is opened, the process is stopped, and the pre-charge test failure information is fed back. If t1 ≤ 35℃, then step S4 is directly performed.

[0117] S4 monitors and determines whether the battery pack temperature t1 is within the normal operating range (0℃, 35℃): If 0℃ < t1 ≤ 35℃, the pre-charge relay 241 is closed first to perform a pre-charge test. When the management device 5 detects that the voltage of the external electrical equipment reaches 90% of the battery pack's system voltage, the pre-charge test is considered passed by default. The discharge relay 23 is closed, and the pre-charge relay 241 is opened after 3 seconds, and the system enters the discharge state. If the pre-charge test fails, the pre-charge relay 241 is opened, the process is stopped, and the pre-charge test failure information is fed back. If t1 ≤ 0℃, step S5 is performed directly.

[0118] S5 monitors and determines whether the battery pack temperature t is within the low-temperature operating range (-15℃, 0℃): If -15℃ < t1 ≤ 0℃, the second target temperature is set to 10℃, the heating film relay 28 is closed, the heating film is turned on, and the battery pack is heated until 10℃ ≤ t ≤ 35℃. Then, the heating film relay 28 is disconnected, the heating film is turned off, and the pre-charge relay 241 is closed to perform a pre-charge test. When the management device 5 detects that the voltage of the external electrical equipment reaches 90% of the battery pack's system voltage, the pre-charge test is considered passed by default. The discharge relay 23 is closed, and the pre-charge relay 241 is disconnected after 3 seconds, and the system enters the discharge state. If the pre-charge test fails, the pre-charge relay 241 is disconnected, the process is stopped, and the pre-charge test failure information is fed back. If t1 ≤ -15℃, then proceed directly to step S6.

[0119] S6 monitors and determines whether the battery pack temperature t is within the ultra-low temperature operating range [-30℃, -15℃]: If -30℃≤t1≤-15℃, set the first target temperature to -5℃ and the second target temperature to 10℃. First, close the liquid thermal relay 27 to turn on the liquid thermal device and heat the battery pack until -5℃≤t≤0℃. Then, close the heating film relay 28 to turn on the heating film to heat the battery pack together until 10℃≤t≤35℃. Then, disconnect the liquid thermal relay 27 and the heating film relay 28, turn off the liquid thermal device and the heating film, and then close the pre-charge relay 241 to perform a pre-charge test. When the management device 5 detects that the voltage of the external electrical equipment reaches 90% of the battery pack's system voltage, the pre-charge test is considered passed by default. Close the discharge relay 23, and disconnect the pre-charge relay 241 after 3 seconds, and the system enters the discharge state. If the pre-charge test fails, disconnect the pre-charge relay 241, stop the process, and provide feedback that the pre-charge test failed.

[0120] Application Example 2

[0121] This application example provides a method for battery pack charging thermal management. The method applies the system provided in Example 1, and the flowchart of the method is as follows: Figure 3 As shown, the method includes the following steps:

[0122] S1 sends a start signal to the management device 5. When the battery pack receives the charging signal, it performs a self-test (including using the voltage acquisition unit and current acquisition unit in the management device 5 to detect the voltage and current of each cell in the battery pack) and feeds back a signal to the judgment unit. If the judgment unit determines that there is a fault, it stops the process, sends a start failure signal, and feeds back the fault information. If it determines that there is no fault, it sets the allowable temperature range for discharge [-40℃, 55℃]. The allowable temperature range includes the ultra-low temperature operating range [-30℃, -15℃], the low temperature operating range (-15℃, 0℃), the normal operating range (0℃, 35℃) and the high temperature operating range (35℃, 55℃). It also transmits a command to the relay control module to close the main negative relay 22 and proceeds to step S2.

[0123] The opening and closing of each relay in the following steps are achieved by transmitting instructions from the judgment unit to the relay control module. To save space, these will not be described in detail.

[0124] The temperature acquisition unit in the S2 management device 5 acquires the temperature of the battery pack. The initial temperature of the battery pack is t1, and the real-time temperature of the battery pack after heating or cooling is t. The unit then sends a signal back to the judgment unit, which determines whether the temperature t1 of the battery pack is within the allowable temperature range [-40℃, 55℃]. If t1 < -40℃ or t1 > 55℃, the process is stopped, a failure message is fed back, and the main negative relay 22 is disconnected after 3 seconds. If -40℃ ≤ t1 ≤ 55℃, the main positive relay 21 is closed, and step S3 is performed.

[0125] The temperature of the battery pack in the following steps is collected by the temperature acquisition unit in the management device 5 and fed back to the judgment unit to determine the temperature range in which t is located. To save space, it will not be described in detail.

[0126] S3 monitors and determines whether the battery pack temperature t1 is within the high-temperature operating range (35℃, 55℃): If 35℃ < t1 ≤ 55℃, the third target temperature is set to 20℃, the liquid cooling relay 26 is closed, the liquid cooling device is turned on, and the battery pack is cooled down until 0℃ < t ≤ 20℃. Then, the liquid cooling relay 26 is disconnected, the liquid cooling device is turned off, and the charging relay 25 is closed, and the system enters the charging state; if t1 ≤ 35℃, then proceed directly to step S4.

[0127] S4 monitors and determines whether the battery pack temperature t is within the normal operating range (0℃, 35℃): If 0℃ < t1 ≤ 35℃, the charging relay 25 is closed and the system enters the charging state; if t1 ≤ 0℃, then proceed directly to step S5.

[0128] S5 monitors and determines whether the battery pack temperature t1 is within the low-temperature operating range (-15℃, 0℃): If -15℃ < t1 ≤ 0℃, the second target temperature is set to 10℃, the heating film relay 28 is closed, the heating film is turned on, and the battery pack is heated until 10℃ ≤ t ≤ 35℃. Then, the heating film relay 28 is disconnected, the heating film is turned off, the charging relay 25 is closed, and the system enters the charging state; if t1 ≤ -15℃, then proceed directly to step S6.

[0129] S6 monitors and determines whether the battery pack temperature t is within the ultra-low temperature operating range [-40℃, -15℃]: If -40℃≤t1≤-15℃, set the first target temperature to -5℃ and the second target temperature to 10℃. First, close the liquid thermal relay 27 to turn on the liquid thermal device and heat the battery pack until -5℃≤t≤0℃. Then, close the heating film relay 28 to turn on the heating film to heat the battery pack together until 10℃≤t≤35℃. Then, disconnect the liquid thermal relay 27 and the heating film relay 28, turn off the liquid thermal device and the heating film, and then close the charging relay 25. The system then enters the charging state.

[0130] As can be seen from the above, the battery pack charging and discharging thermal management method of the present invention has wide applicability and strong practicality. It can broaden the temperature range of battery pack charging and discharging thermal management applications and match the best thermal control auxiliary equipment in four different temperature conditions. In particular, in the ultra-low temperature condition, the liquid heat device is used to raise the temperature first and then the heating film is used to raise the temperature together, which avoids uneven heating of the battery cells, which affects the charging and discharging performance and battery cell life, and helps to extend the service life of the battery system.

[0131] The present invention has been illustrated with the above embodiments to illustrate its detailed structural features. However, the present invention is not limited to the above detailed structural features, that is, it does not mean that the present invention must rely on the above detailed structural features to be implemented. Those skilled in the art should understand that any improvements to the present invention, equivalent substitutions for the components used in the present invention, additions of auxiliary components, and selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

[0132] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the protection scope of the present invention.

[0133] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not describe the various possible combinations separately.

[0134] Furthermore, various different embodiments of the present invention can be combined in any way, as long as they do not violate the spirit of the present invention, they should also be regarded as the content disclosed by the present invention.

Claims

1. A method for thermal management of a battery pack during charging and discharging, characterized in that, The method includes: S1 When the battery pack receives a discharge or charge signal, it performs a self-test; if a fault is found, the process is stopped and fault information is fed back; if no fault is found, the allowable temperature range for discharge or charge is set [T1, T5], which includes the ultra-low temperature operating range [T1, T2], the low temperature operating range (T2, T3], the normal operating range (T3, T4], and the high temperature operating range (T4, T5); the initial temperature of the battery pack is t1, and the real-time temperature of the battery pack after heating or cooling is t; proceed to step S2; S2 Monitor and determine whether the battery pack temperature t1 is within the allowable temperature range [T1,T5]: If t1 < T1 or t1 > T5, stop the process and report a failure message; if T1 ≤ t1 ≤ T5, proceed to step S3; S3 Monitor and determine whether the battery pack temperature t1 is within the high-temperature operating range (T4, T5): If T4 < t1 ≤ T5, set the third target temperature T8, T3 < T8 < T4, turn on the liquid cooling device to cool the battery pack until T3 < t ≤ T8, then turn off the liquid cooling device and the battery pack starts to discharge or charge; if t1 ≤ T4, then proceed directly to step S4. S4 Monitor and determine whether the battery pack temperature t1 is within the normal operating range (T3, T4): If T3 < t1 ≤ T4, then discharge or charge; if t1 ≤ T3, then proceed directly to step S5. S5 Monitor and determine whether the battery pack temperature t1 is within the low-temperature operating range (T2, T3): If T2 < t1 ≤ T3, set a second target temperature T7, T3 < T7 ≤ T4, turn on the heating film to heat the battery pack until T7 ≤ t ≤ T4, then turn off the heating film and the battery pack starts to discharge or charge; if t1 ≤ T2, proceed directly to step S6. S6 monitors and determines whether the battery pack temperature t1 is within the ultra-low temperature operating range [T1,T2]: If T1≤t1≤T2, set the first target temperature T6; if T2<T6≤T3, set the second target temperature T7; if T3<T7≤T4, turn on the liquid heat treatment device to heat the battery pack until T6≤t≤T3, then turn on the heating film to heat the battery pack together until T7≤t≤T4, then turn off the liquid heat treatment device and the heating film, and the battery pack begins to discharge or charge.

2. The method of battery pack charge-discharge thermal management of claim 1, wherein, The difference between T6 and T2 is 5~15℃.

3. The method of battery pack charge-discharge thermal management of claim 1, wherein, The difference between T7 and T3 is 10~15℃.

4. The method of battery pack charge-discharge thermal management of claim 1, wherein, The allowable temperature range for the discharge is [-30℃, 35℃].

5. The method for thermal management of battery pack charging and discharging according to claim 1, characterized in that, The allowable temperature range for charging is [-40℃, 35℃].

6. The method for battery pack charging and discharging thermal management according to claim 1, characterized in that, The cryogenic operating range of the discharge is [-30℃, -15℃].

7. The method for battery pack charging and discharging thermal management according to claim 1, characterized in that, The ultra-low temperature operating range of the charging is [-40℃, -15℃].

8. The method for thermal management of a battery pack during charging and discharging according to claim 1, characterized in that, The low-temperature operating range for both discharge and charge is (-15℃, 0℃).

9. The method for thermal management of a battery pack during charging and discharging according to claim 1, characterized in that, The normal operating range for both discharge and charge is (0℃, 35℃).

10. The method for thermal management of a battery pack during charging and discharging according to claim 1, characterized in that, The difference between T4 and T8 is 10~15℃.

11. The method for thermal management of a battery pack during charging and discharging according to claim 1, characterized in that, The high-temperature operating range for both discharge and charge is (35℃, 55℃).

12. The method for battery pack charging and discharging thermal management according to claim 11, characterized in that, The allowable temperature range for the discharge is [-30℃, 55℃].

13. The method for battery pack charging and discharging thermal management according to claim 11, characterized in that, The allowable temperature range for charging is [-40℃, 55℃].

14. The method for thermal management of a battery pack during charging and discharging according to claim 1, characterized in that, When the discharge requirement is met in step S4, step S5 or step S6, a pre-charge test is performed first. If the pre-charge test passes, the discharge process begins. If the pre-charge test fails, the process is stopped and a pre-charge test failure message is sent.

15. The method for battery pack charging and discharging thermal management according to claim 14, characterized in that, The pre-charge detection includes detecting the voltage of external electrical equipment.

16. The method for battery pack charging and discharging thermal management according to claim 14, characterized in that, The pre-charge test pass criteria include the voltage of the external electrical equipment reaching 90% or more of the battery pack's system voltage.

17. A management device for thermal management of a battery pack during charging and discharging, characterized in that, The management device (5) is used to implement the method described in any one of claims 1-16. The management device (5) includes a temperature acquisition unit, a judgment unit, and a control unit that are electrically connected in sequence. The control unit is electrically connected to the liquid heat device, the heating film, and the liquid cooling device. The temperature acquisition unit is used to acquire the temperature of the battery pack and feed it back to the judgment unit. The initial temperature of the battery pack is t1, and the real-time temperature of the battery pack after heating or cooling is t. When the judgment unit determines that T1≤t1≤T2, the control unit controls the liquid heating device to heat the battery pack. When the judgment unit determines that T6≤t≤T3, the control unit controls the heating film to open and heat the battery pack together. When the judgment unit determines that T3<t≤T4, the control unit controls the liquid heating device and the heating film to close, and the control unit controls the battery pack to start discharging or charging. Wherein, T2<T6≤T3; until the judgment unit determines that T2<t1≤T3. When T7 ≤ t ≤ T4, the control unit controls the heating film to heat the battery pack until the judgment unit determines that T7 ≤ t ≤ T4. At this time, the control unit controls the heating film to turn off and the control unit controls the battery pack to start discharging or charging; where T3 < T7 ≤ T4. When the judgment unit determines that T3 < t1 ≤ T4, the control unit directly controls the battery pack to start discharging or charging. When the judgment unit determines that T4 < t1 ≤ T5, the control unit controls the liquid cooling device to turn on to cool the battery pack until the judgment unit determines that T3 < t ≤ T8. At this time, the control unit controls the liquid cooling device to turn off and the control unit controls the battery pack to start discharging or charging; where T3 < T8 < T4.

18. The management device according to claim 17, characterized in that, The management device (5) also includes a voltage acquisition unit and a current acquisition unit, both of which are electrically connected to the judgment unit.

19. The management device according to claim 17, characterized in that, The judgment unit includes a CAN communication module.

20. The management device according to claim 17, characterized in that, The control unit includes a relay control module.

21. A system for thermal management of a battery pack during charging and discharging, characterized in that, The system includes a high-voltage device (1) and a management device (5) as described in any one of claims 17-20; The high-voltage device (1) is provided with positive and negative interfaces and positive and negative circuits corresponding to the battery pack, external electrical equipment, external charging equipment, liquid heat device and heating film respectively; The control unit in the management device (5) is electrically connected to the liquid heat device and the heating film through the high-pressure device (1).

22. The battery pack charging and discharging thermal management system according to claim 21, characterized in that, The high-voltage device (1) is provided with an input total positive terminal interface (111) and an input total negative terminal interface (112) corresponding to the total positive output terminal and the total negative output terminal of the battery pack, a discharge output positive terminal interface (121) and a discharge output negative terminal interface (122) for connecting the external electrical equipment, a charging input positive terminal interface (131) and a charging input negative terminal interface (132) for connecting the external charging equipment, and a liquid heat output positive terminal interface (151) and a liquid heat output negative terminal interface (152), a heating film output positive terminal interface (161) and a heating film output negative terminal interface (162) for supplying power to the heating film and the liquid heat device, respectively. The main input positive terminal (111) is electrically connected to the discharge output positive terminal (121) to form the positive main circuit. The charging input positive terminal (131), the liquid thermal output positive terminal (151) and the heating film output positive terminal (161) are respectively connected to the positive main circuit to form the charging positive terminal branch, the liquid thermal positive terminal branch and the heating film positive terminal branch. The input main negative terminal interface (112) is electrically connected to the discharge output negative terminal interface (122) to form the negative main circuit. The charging input negative terminal interface (132), the heating film output negative terminal interface (162) and the liquid heat output negative terminal interface (152) are respectively connected to the negative main circuit to form the charging negative terminal branch, the liquid heat negative terminal branch and the heating film negative terminal branch.

23. The battery pack charging and discharging thermal management system according to claim 22, characterized in that, A main positive relay (21) is provided on the positive main line to control the opening and closing of the positive main line.

24. The battery pack charging and discharging thermal management system according to claim 23, characterized in that, On the positive main line, a manual maintenance switch (41) is provided between the input main positive interface (111) and the main positive relay (21).

25. The battery pack charging and discharging thermal management system according to claim 23, characterized in that, On the positive main line, a discharge relay (23) is provided between the main positive relay (21) and the discharge output positive interface (121) to control the opening and closing of the battery pack discharge behavior.

26. The battery pack charging and discharging thermal management system according to claim 25, characterized in that, The charging negative electrode branch, the liquid heat negative electrode branch, and the heating film negative electrode branch positive electrode branch are all connected between the main positive relay (21) and the discharge relay (23).

27. The battery pack charging and discharging thermal management system according to claim 25 or 26, characterized in that, A pre-charge detection branch is connected in parallel across the two ends of the discharge relay (23) for pre-charge detection before the battery pack is discharged.

28. The battery pack charging and discharging thermal management system according to claim 27, characterized in that, The precharge detection branch is equipped with a precharge resistor (242) and a precharge relay (241) connected in series.

29. The battery pack charging and discharging thermal management system according to claim 22, characterized in that, The charging positive electrode branch, the liquid thermal positive electrode branch, and the heating film positive electrode branch are equipped with corresponding charging relays (25), liquid thermal relays (27), and heating film relays (28) to control the opening and closing of the corresponding positive electrode branch.

30. The battery pack charging and discharging thermal management system according to claim 22, characterized in that, A main negative relay (22) is installed on the negative main circuit to control the opening and closing of the negative main circuit.

31. The battery pack charging and discharging thermal management system according to claim 30, characterized in that, Each negative branch is connected between the main negative relay (22) and the discharge output negative interface (122).

32. The battery pack charging and discharging thermal management system according to claim 30, characterized in that, On the negative main line, a shunt (43) is provided between the input main negative interface (112) and the main negative relay (22).

33. The battery pack charging and discharging thermal management system according to claim 22, characterized in that, Each heating film negative electrode branch and liquid heat negative electrode branch is respectively provided with a corresponding heating film safety device (33) and a liquid heat safety device (32).

34. The battery pack charging and discharging thermal management system according to claim 22, characterized in that, Both the heating film negative electrode branch and the liquid thermal negative electrode branch are first connected to the Hall sensor (42) and then connected to the negative electrode main circuit.

35. The battery pack charging and discharging thermal management system according to claim 22, characterized in that, The high-voltage device (1) is also provided with a liquid-cooled output positive interface (141) and a liquid-cooled output negative interface (142) corresponding to the liquid-cooling device. The liquid-cooled output positive interface (141) is electrically connected to the input total positive interface (111) to form a liquid-cooled positive branch, and the liquid-cooled output negative interface (142) is electrically connected to the input total negative interface (112) to form a liquid-cooled negative branch.

36. The battery pack charging and discharging thermal management system according to claim 35, characterized in that, The liquid-cooled positive branch is connected between the main positive relay (21) and the discharge relay (23).

37. The battery pack charging and discharging thermal management system according to claim 36, characterized in that, A liquid-cooled relay (26) is installed on the liquid-cooled positive electrode branch.

38. The battery pack charging and discharging thermal management system according to claim 36, characterized in that, The liquid-cooled negative branch is connected between the main negative relay (22) and the discharge output negative interface (122).

39. The battery pack charging and discharging thermal management system according to claim 36, characterized in that, A liquid-cooled safety device (31) is installed on the liquid-cooled negative electrode branch.

Images