Battery Pack Charging and Discharging Control Method and System

Abstract

The present invention discloses a method and system for controlling charge and discharge of a battery pack. The control method includes a first method, and the first method comprises: real-time detecting state parameters of battery packs in the battery pack and environmental parameters of the environment inside the battery pack, where the environmental parameters include environmental humidity and environmental temperature; generating current fault parameters related to water immersion by combining the values of environmental humidity and environmental temperature; generating a first control parameter by combining the fault parameters and the state parameters; when the working current of the battery pack is lower than a preset current threshold, controlling the states of the charging switch and the discharging switch of the battery pack based on the first control parameter. The above control method generates control parameters through the detection of multi-factor parameters, making the waterproof detection more comprehensive and accurate, and the risk of water immersion can be identified and processed in the early stage, reducing the probability of battery short circuit and fire accidents; in addition, there is no need to adopt a detection model with a complex structure, effectively reducing the cost of the battery pack.

Description

Technical Field

[0001] The present invention relates to the technical field of rechargeable battery control, and particularly to a method and system for controlling charging and discharging of a battery pack. Background Art

[0002] In the use of electric vehicles and energy storage devices, the safety and reliability of the battery pack are of crucial importance. However, during the daily use of the battery pack, changes in the external environment, such as rain and vehicle wading, may lead to a decline in the waterproof performance of the battery pack and even the risk of water immersion. In this case, a short circuit may occur inside the battery pack, thus triggering safety accidents such as fires. Therefore, how to effectively detect and control the water immersion of the battery pack has become an urgent problem to be solved.

[0003] Currently, the waterproof level of battery packs on the market is generally IPX7. Although it has good waterproof performance, its waterproof ability may gradually degrade in the face of complex usage environments. Traditional water immersion detection schemes have many deficiencies. Some battery packs lack a perfect water immersion detection mechanism, and the existing detection technologies often rely on a detection circuit of a single element or a complex detection model. This method not only lacks flexibility and comprehensiveness, but also has problems such as slow response speed and high detection cost, and it is difficult to make an accurate diagnosis in the initial stage of the battery pack being water immersed. Summary of the Invention

[0004] The purpose of the present invention is to provide a method and system for controlling charging and discharging of a battery pack that can simply, effectively, and based on multiple elements improve the waterproof performance of the battery pack.

[0005] To achieve the above purpose, the present invention provides a method for controlling charging and discharging of a battery pack, which includes a first method. The first method includes:

[0006] Real-time detecting the state parameters of the battery group in the battery pack and the environmental parameters of the environment inside the battery pack, where the environmental parameters include environmental humidity and environmental temperature;

[0007] Combining the values of the environmental humidity and the environmental temperature to generate a current fault parameter related to water immersion;

[0008] Combining the fault parameter and the state parameters to generate a first control parameter;

[0009] When the working current of the battery pack is lower than a preset current threshold, controlling the states of the charging switch and the discharging switch of the battery pack based on the first control parameter.

[0010] Preferably, when the following first condition and second condition are simultaneously satisfied, the content of the first control parameter includes: allowing the charging switch and the discharging switch to be turned on;

[0011] The first condition: the state parameter is within the normal range;

[0012] The second condition: the environmental humidity is within the first humidity value range.

[0013] Preferably, when the first condition and the following third condition are satisfied simultaneously, the content of the first control parameter includes: allowing the discharge switch to conduct and prohibiting the charge switch from conducting;

[0014] The third condition: the environmental humidity is within the second humidity value range, and the environmental temperature is greater than or equal to a preset temperature threshold, and the second humidity value range is greater than the first humidity value range.

[0015] Preferably, when the first condition and the following fourth condition are satisfied simultaneously, the content of the first control parameter includes: prohibiting the discharge switch from conducting and prohibiting the charge switch from conducting;

[0016] The fourth condition: the environmental humidity is within the third humidity value range, and the environmental temperature is greater than or equal to a preset temperature threshold, and the third humidity value range is greater than the second humidity value range.

[0017] Preferably, the state parameter includes the temperature and voltage of the battery cells in the battery pack.

[0018] Preferably, it further includes a second method, and the second method includes:

[0019] Provide a water immersion detection circuit, the water immersion detection circuit includes a reference resistor and a reference voltage, the reference resistor is arranged at the bottom of the battery pack, and the reference resistor is electrically connected to the reference voltage through a voltage dividing resistor;

[0020] Detect the voltage between the reference resistor and the voltage dividing resistor in real time to obtain a detection voltage;

[0021] Generate a second control parameter according to the relationship between the detection voltage and the reference voltage;

[0022] When the working current of the battery pack is lower than a preset current threshold, control the states of the charge switch and the discharge switch of the battery pack based on the first control parameter and / or the second control parameter.

[0023] Preferably, when the ratio of the detected voltage to the reference voltage is within the first ratio value range, the content of the second control parameter includes: allowing the charging switch and the discharging switch to be turned on; when the ratio of the detected voltage to the reference voltage is within the second ratio value range, the content of the second control parameter includes: allowing the discharging switch to be turned on and prohibiting the charging switch from being turned on; when the ratio of the detected voltage to the reference voltage is within the third ratio value range, the content of the second control parameter includes: prohibiting the charging switch from being turned on and prohibiting the discharging switch from being turned on; the first ratio value range is greater than the second ratio value range, and the second ratio value range is greater than the third ratio value range.

[0024] The present invention also provides a battery pack charge and discharge control system, which includes a controller and a charging switch and a discharging switch electrically connected to the controller, and the controller controls the states of the charging switch and the discharging switch based on the battery pack charge and discharge control method described above.

[0025] The present invention also provides a battery pack charge and discharge control system, which includes:

[0026] one or more processors;

[0027] a memory;

[0028] and one or more programs, wherein the one or more programs are stored in the memory and are configured to be executed by the one or more processors, and the programs include instructions for executing the battery pack charge and discharge control method described above.

[0029] The present invention also provides a computer-readable storage medium, which includes a computer program, and the computer program can be executed by a processor to complete the battery pack charge and discharge control method described above.

[0030] Compared with the prior art, the battery pack charge and discharge control method provided by the above technical solution of the present invention generates a fault parameter related to water immersion based on the ambient humidity and ambient temperature of the environment inside the battery pack, and generates a control parameter by combining the fault parameter and the state parameter of the battery pack. Then, when the battery pack is in a silent state, the charging switch and the discharging switch are controlled based on the control parameter, thereby avoiding potential safety hazards caused by water immersion. It can be seen that the above control method generates a control parameter by detecting multi-factor parameters, making the waterproof detection more comprehensive and accurate, and the risk of water immersion can be identified and processed at an early stage, reducing the probability of battery short circuit and fire accidents; in addition, there is no need to adopt a detection model with a complex structure, effectively reducing the cost of the battery pack. Description of the Drawings

[0031] Figure 1This is the flowchart of the battery pack charge and discharge control method in the embodiment of the present invention.

[0032] Figure 2 This is the principle structure diagram of the battery pack charge and discharge control method in the embodiment of the present invention.

[0033] Figure 3 This is the principle structure diagram of the battery pack charge and discharge control system in the embodiment of the invention.

[0034] Figure 4 This is the schematic diagram of the water immersion detection circuit in the embodiment of the present invention. Detailed implementation manners

[0035] To describe in detail the technical content, structural features, achieved objectives and effects of the present invention, the following will be described in detail in conjunction with the embodiments and with reference to the drawings.

[0036] This embodiment discloses a battery pack charge and discharge control method for preventing safety hazards caused by starting the battery pack in the case of water immersion of the battery pack. As Figure 1 and Figure 2 , the control method includes a first method:

[0037] S10: Real-time detect the state parameters of the battery pack BT in the battery pack and the environmental parameters of the environment inside the battery pack. The environmental parameters include environmental humidity and environmental temperature. Detecting the state parameters of the battery pack is to confirm that the battery pack BT is in a normal state, that is, it can safely enter the charging or discharging state.

[0038] S11: Generate a current fault parameter related to water immersion in combination with the values of environmental humidity and environmental temperature. When the battery pack is water immersed or water seeps, the humidity of the internal environment of the battery pack will increase, and the environmental humidity is related to the environmental temperature. Generally, the lower the environmental temperature, the relatively higher the environmental humidity. Therefore, when the environmental humidity increases, if the environmental temperature is also relatively high, it indicates a water immersion fault. This improves the accuracy. Adding the detection of current (battery state) is because when the battery is static, the environment inside the battery pack is more stable and the detection is more accurate

[0039] S12: Generate a first control parameter in combination with the fault parameter and the state parameter.

[0040] S13: When the working current of the battery pack is lower than a preset current threshold, control the states of the charging switch K1 and the discharging switch K2 of the battery pack based on the first control parameter. It should be noted that the monitoring of the above state parameters and environmental parameters and the generation of the first control parameter are carried out in real time, and this process covers the static state process and the working process of the battery pack. However, the control actions on the charging switch K1 and the discharging switch K2 based on the first control parameter can only be carried out when the working current of the battery pack is lower than the preset current threshold, so as to avoid potential safety hazards due to the forced control of the first control parameter during the normal operation of the battery pack. The theoretical value of this current threshold can be zero. In this embodiment, this current threshold is set to 5A.

[0041] On the other hand, when the following first condition and second condition are satisfied simultaneously, the content of the first control parameter includes: allowing the charging switch K1 and the discharging switch K2 to conduct.

[0042] First condition: The state parameter is within the normal range, that is, the battery pack is in a healthy state;

[0043] Second condition: The environmental humidity is within the first humidity value range.

[0044] Specifically, the state parameter includes the temperature and voltage of the battery cells in the battery pack BT. Therefore, the health state of the battery pack BT is judged by the temperature and voltage of the battery cells in the battery pack BT.

[0045] In addition, when the first condition and the following third condition are satisfied simultaneously, the content of the first control parameter includes: allowing the discharging switch K2 to conduct and prohibiting the charging switch K1 from conducting.

[0046] Third condition: The environmental humidity is within the second humidity value range, and the environmental temperature is greater than or equal to the preset temperature threshold, and the second humidity value range is greater than the first humidity value range.

[0047] Furthermore, when the first condition and the following fourth condition are satisfied simultaneously, the content of the first control parameter includes: prohibiting the discharging switch K2 from conducting and prohibiting the charging switch K1 from conducting;

[0048] Fourth condition: The environmental humidity is within the third humidity value range, and the environmental temperature is greater than or equal to the preset temperature threshold, and the third humidity value range is greater than the second humidity value range.

[0049] Specifically:

[0050] The first humidity value range is: [0%, 50%];

[0051] The second humidity value range is: (50%, 75%];

[0052] The third humidity value range is: (75%, 100%].

[0053] Taking the temperature threshold TH of 25 °C as an example:

[0054] When RH (ambient humidity) ∈ [0%, 50%], there is no need to refer to the ambient temperature, and the battery pack is allowed to charge and discharge.

[0055] When RH ∈ (50%, 75%], if TH ≥ 25 °C, it indicates a first-level water immersion fault, an alarm signal is issued, discharging is allowed, but charging is prohibited.

[0056] When RH ∈ (75%, 100%], if TH ≥ 25 °C, it indicates a second-level water immersion fault, an alarm signal is issued, charging is prohibited, and discharging is also prohibited.

[0057] For the above control method, fault parameters related to water immersion are generated based on the ambient humidity and ambient temperature inside the battery pack, and control parameters are generated by combining the fault parameters and the state parameters of the battery pack BT. Then, when the battery pack is in a silent state, the charging switch K1 and the discharging switch K2 are controlled based on the control parameters, thereby avoiding potential safety hazards caused by water immersion. It can be seen that the above control method generates control parameters through the detection of multi-element parameters, making the waterproof detection more comprehensive and accurate, and the water immersion risk can be identified and processed at an early stage, reducing the probability of battery short-circuit and fire accidents; in addition, there is no need to adopt a detection model with a complex structure, effectively reducing the cost of the battery pack.

[0058] On the other hand, the battery pack charge and discharge control method of the present invention further includes a second method, which detects whether there is water immersion inside the battery pack through a water immersion detection circuit, such as Figure 2 and Figure 4 , and this second method includes:

[0059] The water immersion detection circuit includes a reference resistor R0 and a reference voltage VC. The reference resistor R0 is arranged at the bottom of the battery pack, and the reference resistor R0 is electrically connected to the reference voltage VC through a voltage-dividing resistor R1;

[0060] The voltage between the reference resistor R0 and the voltage-dividing resistor R1 is detected in real time to obtain a detection voltage VX;

[0061] A second control parameter is generated according to the relationship between the detection voltage VX and the reference voltage VC;

[0062] When the working current of the battery pack is lower than a preset current threshold, the states of the charging switch K1 and the discharging switch K2 of the battery pack are controlled based on the first control parameter and / or the second control parameter.

[0063] It should be noted that when either the first control parameter or the second control parameter represents that there is a current water immersion fault and a control action needs to be issued, the corresponding control action can be issued.

[0064] On the other hand, when the ratio of the detected voltage VX to the reference voltage VC is within the first ratio value range, the content of the second control parameter includes: allowing the charging switch K1 and the discharging switch K2 to conduct.

[0065] When the ratio of the detected voltage VX to the reference voltage VC is within the second ratio value range, the content of the second control parameter includes: allowing the discharging switch K2 to conduct and prohibiting the charging switch K1 from conducting.

[0066] When the ratio of the detected voltage VX to the reference voltage VC is within the third ratio value range, the content of the second control parameter includes: prohibiting the charging switch K1 from conducting and prohibiting the discharging switch K2 from conducting.

[0067] The first ratio value range is greater than the second ratio value range, and the second ratio value range is greater than the third ratio value range.

[0068] Specifically:

[0069] The first ratio value range is: (1 / 3, 1 / 2];

[0070] The second ratio value range is: (1 / 4, 1 / 3];

[0071] The third ratio value range is: [0, 1 / 4].

[0072] The working principle of the above water immersion detection circuit is as follows:

[0073] For example Figure 4 , the reference voltage VC is 3.3V, the reference resistor R0 is 10KΩ, the voltage dividing resistor R1 is 10KΩ, there is a sampling node J0 between the reference resistor R0 and the voltage dividing resistor R1, and the signal acquisition end is connected to the sampling node J0 through a current limiting resistor R2, and the current limiting resistor R2 is 2KΩ.

[0074] When the battery pack is not water immersed, the detected voltage VX collected by the signal acquisition end is the voltage (1.65V) across the reference resistor R0, that is, 1 / 2 of the reference voltage VC.

[0075] When the battery pack is water immersed, water will form a conductive path at the bottom of the battery pack, thereby forming a water immersion equivalent resistor RX in parallel with the reference resistor R0 across the two ends of the reference resistor R0. Under the influence of this water immersion equivalent resistor RX, the voltage level across the reference resistor R0 will decrease.

[0076] For example, when the battery pack is slightly flooded, a parallel equivalent flooded resistance RX of 10 KΩ is generated across the reference resistor R0. After the equivalent flooded resistance RX is connected in parallel with the reference resistor R0, the detection voltage collected by the signal acquisition terminal becomes smaller, becoming 1.1 V, which is also 1 / 3 of the reference voltage VC. Then, when the detection voltage VX drops to 1.1 V, an alarm signal is issued, and at the same time, the discharge switch K2 is allowed to conduct, and the charging switch K1 is prohibited from conducting.

[0077] When the battery pack is severely flooded, a parallel equivalent flooded resistance RX of 5 KΩ is generated across the reference resistor R0. After the equivalent flooded resistance RX is connected in parallel with the reference resistor R0, the detection voltage collected by the signal acquisition terminal becomes smaller, becoming 0.82 V, which is also 1 / 4 of the reference voltage VC. Then, when the detection voltage VX drops to 0.82 V, an alarm signal is issued, and at the same time, the charging switch K1 is prohibited from conducting, and the discharge switch K2 is prohibited from conducting.

[0078] In this embodiment, whether flooding occurs and the severity of flooding are judged by the change in the detected voltage VX collected. The more flooded, the smaller the detected voltage VX.

[0079] In another preferred embodiment of the present invention, a battery pack charge and discharge control system is also disclosed, as Figure 3 and Figure 4 , which includes a controller and a charging switch K1 and a discharge switch K2 electrically connected to the controller. The controller controls the states of the charging switch K1 and the discharge switch K2 based on the battery pack charge and discharge control method in the above embodiment.

[0080] Specifically, the control system further includes a temperature and humidity sensor, a battery state information collector, a flooding detection circuit, and a fault alarm connected to the controller. Among them, the temperature and humidity sensor is used to detect the environmental humidity and environmental temperature inside the battery pack. The battery state information collector is used to collect the temperature, voltage, and charge and discharge current of the battery cells of the battery pack inside the battery pack. In this embodiment, the battery state information collector includes an AFE (analog front-end acquisition chip).

[0081] The present invention also discloses another battery pack charge and discharge control system, which includes one or more processors, a memory, and one or more programs. Among them, the one or more programs are stored in the memory and configured to be executed by the one or more processors. The programs include instructions for executing the battery pack charge and discharge control method as described above. The processor can be a general-purpose central processing unit (CPU), a microprocessor, an application specific integrated circuit (ASIC), or one or more integrated circuits, which are used to execute relevant programs to implement the functions required by the modules in the battery pack charge and discharge control system of the embodiments of the present application, or to execute the battery pack charge and discharge control method of the method embodiments of the present application.

[0082] The present invention also discloses a computer-readable storage medium, which includes a computer program that can be executed by a processor to complete the battery pack charge and discharge control method as described above. The computer-readable storage medium can be any available medium that can be accessed by a computer or a data storage device such as a server or a data center that integrates one or more available media. The available medium can be a read-only memory (ROM), a random access memory (RAM), a magnetic medium, such as a floppy disk, a hard disk, a magnetic tape, a magnetic disk, or an optical medium, such as a digital versatile disc (DVD), or a semiconductor medium, such as a solid-state disk (SSD), etc.

[0083] The embodiments of the present application also disclose a computer program product or a computer program. The computer program product or the computer program includes computer instructions, and the computer instructions are stored in a computer-readable storage medium. The processor of the electronic device reads the computer instructions from the computer-readable storage medium, and the processor executes the computer instructions, so that the electronic device executes the above-mentioned battery pack charge and discharge control method.

[0084] The above-disclosed are only the preferred embodiments of the present invention. Of course, the scope of the rights of the present invention cannot be limited thereby. Therefore, equivalent changes made according to the scope of the patent application of the present invention still fall within the scope covered by the present invention.

Claims

1. A method for controlling charging and discharging of a battery pack, characterized in that, Comprising a first method, the first method comprising: Real-time detecting state parameters of battery packs within the battery pack and environmental parameters of the environment within the battery pack, the environmental parameters including environmental humidity and environmental temperature; the state parameters including the temperature and voltage of battery cells within the battery pack; Generating a current fault parameter related to water immersion in combination with the values of the environmental humidity and the environmental temperature; Generating a first control parameter in combination with the fault parameter and the state parameters; When the operating current of the battery pack is lower than a preset current threshold, controlling the states of the charging switch and the discharging switch of the battery pack based on the first control parameter, the operating current of the battery pack being lower than the preset current threshold indicating that the battery pack is in a silent state; when the following first condition and second condition are satisfied simultaneously, the content of the first control parameter includes: allowing the charging switch and the discharging switch to conduct; First condition: The state parameters are within a normal range; Second condition: The environmental humidity is within a first humidity numerical range; When the first condition and the following third condition are satisfied simultaneously, the content of the first control parameter includes: allowing the discharging switch to conduct and prohibiting the charging switch from conducting; Third condition: The environmental humidity is within a second humidity numerical range and the environmental temperature is greater than or equal to a preset temperature threshold, the second humidity numerical range being greater than the first humidity numerical range; When the first condition and the following fourth condition are satisfied simultaneously, the content of the first control parameter includes: prohibiting the discharging switch from conducting and prohibiting the charging switch from conducting; Fourth condition: The environmental humidity is within a third humidity numerical range and the environmental temperature is greater than or equal to a preset temperature threshold, the third humidity numerical range being greater than the second humidity numerical range.

2. The battery pack charge and discharge control method according to claim 1, characterized in that, Further comprising a second method, the second method comprising: Providing a water immersion detection circuit, the water immersion detection circuit including a reference resistor and a reference voltage, the reference resistor being disposed at the bottom of the battery pack, the reference resistor being electrically connected to the reference voltage through a voltage dividing resistor; Real-time detecting the voltage between the reference resistor and the voltage dividing resistor to obtain a detection voltage; Generating a second control parameter according to the relationship between the detection voltage and the reference voltage; When the operating current of the battery pack is lower than a preset current threshold, controlling the states of the charging switch and the discharging switch of the battery pack based on the first control parameter and / or the second control parameter.

3. The battery pack charge and discharge control method according to claim 2, wherein When the ratio of the detected voltage to the reference voltage is within the first ratio value range, the content of the second control parameter includes: allowing the charging switch and the discharging switch to be turned on; when the ratio of the detected voltage to the reference voltage is within the second ratio value range, the content of the second control parameter includes: allowing the discharging switch to be turned on and prohibiting the charging switch from being turned on; when the ratio of the detected voltage to the reference voltage is within the third ratio value range, the content of the second control parameter includes: prohibiting the charging switch from being turned on and prohibiting the discharging switch from being turned on; the first ratio value range is greater than the second ratio value range, and the second ratio value range is greater than the third ratio value range.

4. A battery pack charge and discharge control system, characterized in that, It includes a controller and a charging switch and a discharging switch electrically connected to the controller, and the controller controls the states of the charging switch and the discharging switch based on the battery pack charge and discharge control method according to any one of claims 1 to 3.

5. A battery pack charge and discharge control system, characterized in that, Comprising: One or more processors; A memory; And one or more programs, wherein the one or more programs are stored in the memory and are configured to be executed by the one or more processors, and the programs include instructions for executing the battery pack charge and discharge control method according to any one of claims 1 to 3.

6. A computer-readable storage medium, characterized in that, It includes a computer program, and the computer program can be executed by a processor to complete the battery pack charge and discharge control method according to any one of claims 1 to 3.

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