Battery pack SOH value detection method

Abstract

The invention provides a battery pack SOH value detection method, which is suitable for a 12V battery pack and comprises the following steps: discharging the battery pack until the voltage of the battery pack is reduced to an under-voltage threshold value; charging the battery pack with a first preset charge value until the electric quantity of the battery pack is 100%; and acquiring the current environment temperature of the battery pack and the actual capacity of the battery pack at the current environment temperature, and converting the actual capacity of the battery pack at the current environment temperature and the rated capacity of the battery pack at the current environment temperature to obtain the actual SOH value of the battery pack. The problem that a battery management system in the prior art cannot accurately estimate the SOH value of the small battery pack is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of battery pack SOH value detection, and more specifically, to a method for detecting the SOH value of a battery pack. Background Art

[0002] With the continuous development of new energy vehicle technology, the battery packs carried by vehicles are also constantly optimized. Generally, a power battery pack and a 12V small battery pack need to be carried on a new energy vehicle. The power battery pack provides power for the whole vehicle, and the small battery pack provides power for the electrical appliances on the vehicle.

[0003] However, limited by the current charging strategy of the battery pack, that is, the power battery pack continuously supplies power to the small battery pack, making the small battery pack basically in a fully charged state, so that the battery management system (BMS) cannot accurately estimate the health state of the small battery pack, that is, the SOH (State Of Health) value. Summary of the Invention

[0004] The main object of the present invention is to provide a method for detecting the SOH value of a battery pack to solve the problem that the battery management system in the prior art cannot accurately estimate the SOH value of the small battery pack.

[0005] To achieve the above object, according to one aspect of the present invention, a method for detecting the SOH value of a battery pack applicable to a 12V battery pack is provided. The detection method includes: discharging the battery pack until the voltage of the battery pack drops to an undervoltage threshold; charging the battery pack with a first predetermined charge value until the battery pack's power is 100%; obtaining the current ambient temperature of the battery pack and the actual capacity of the battery pack at the current ambient temperature, and converting the actual capacity of the battery pack at the current ambient temperature into the rated capacity of the battery pack at the current ambient temperature to obtain the actual SOH value of the battery pack.

[0006] Further, during the process of discharging the battery pack, the detection method further includes: the battery pack releases current at a second predetermined charge.

[0007] Further, the second predetermined charge is: 0.8C - 1.2C.

[0008] Further, before discharging the battery pack, the detection method further includes: obtaining the static time of the vehicle and the remaining power of the power battery; judging whether to discharge the battery pack according to the duration of the static time and the remaining power of the power battery.

[0009] Further, the method for judging whether to discharge the battery pack according to the duration of the static time and the remaining power of the power battery includes: when the static time is greater than 6 hours and at the same time, the remaining power of the power battery is greater than 50%, automatically discharging the battery pack.

[0010] Further, the method for discharging the battery pack includes: turning on an electrical appliance electrically connected to the battery pack in the vehicle, and the voltage of the electrical appliance is less than or equal to 12V.

[0011] Further, the detection method further includes: when the voltage of the battery pack drops to the undervoltage threshold, an undervoltage warning is issued; thereafter, charging of the battery pack is started.

[0012] Further, the method for charging the battery pack with a first predetermined charge includes: the first predetermined charge is less than 1C; the detection method further includes: controlling the power battery of the vehicle to charge the battery pack with a charge less than 1C.

[0013] Further, the battery pack SOH value detection method further includes: constructing a database of the actual ambient temperature and rated capacity of the battery pack; after obtaining the current ambient temperature of the battery pack, matching it with the database to obtain the rated capacity corresponding to the current ambient temperature.

[0014] Further, during the process of discharging the battery pack, the voltage, current and temperature of the battery pack are obtained at every predetermined time interval; when the voltage, current or temperature is abnormal, the discharging is stopped.

[0015] Applying the technical solution of the present invention, according to the battery pack SOH value detection method provided by the present application, by completely discharging the battery pack to the undervoltage threshold and then charging it to the full charge state, the actual capacity of the battery pack at the current ambient temperature can be obtained, so as to more accurately calculate the SOH value and provide accurate information on the battery health status for users and maintenance personnel. Users can actively start the SOH detection function through the central control screen according to the usage situation of the vehicle and the status of the battery pack, or the whole vehicle automatically starts according to preset conditions, which increases the flexibility and convenience of detection. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The accompanying drawings forming a part of this application are used to provide a further understanding of the present invention. The schematic embodiments and descriptions thereof of the present invention are used to explain the present invention and do not constitute an improper limitation to the present invention. In the drawings:

[0017] Figure 1 A flowchart showing an embodiment of the battery pack SOH value detection method according to the present invention is shown. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0018] It should be noted that, without conflict, the embodiments in this application and the features in the embodiments can be combined with each other. The present invention will be described in detail below with reference to the drawings and in conjunction with the embodiments.

[0019] As mentioned in the background art, with the increasing penetration rate of new energy vehicles, the ownership of various new energy vehicles in the market has been continuously rising rapidly. It has become an industry trend to replace the 12V lead-acid battery with a lithium battery in pure electric models. However, the current charging strategy of small lithium battery packs causes the small battery packs to be basically fully charged, and the BMS cannot accurately estimate the true state of the battery packs. Automobile manufacturers or vehicle owners do not have a suitable method to master the true SOH of the current battery pack and cannot evaluate its health status. The current SOH detection accuracy of the BMS can only reach 8% accuracy, and for small batteries that are often fully charged, it is even more impossible to accurately evaluate the SOH. Vehicle owners cannot make decisions on whether the battery pack should be maintained or replaced. Even vehicle annual inspection institutions cannot conduct capacity detection and calibration on it. Therefore, in view of the above technical problems, the battery pack SOH value detection method provided in this application is applicable to 12V battery packs and specifically includes: discharging the battery pack until the voltage of the battery pack drops to the undervoltage threshold; charging the battery pack with a first predetermined charge until the battery pack's power reaches 100%; obtaining the current ambient temperature of the battery pack and the actual capacity of the battery pack at the current ambient temperature, and converting the actual capacity of the battery pack at the current ambient temperature into the rated capacity of the battery pack at the current ambient temperature to obtain the actual SOH value of the battery pack. In this way, the true capacity of the battery pack can be obtained, and the true SOH value of the battery pack can be obtained. Users can accurately evaluate the status of the battery pack according to the detected SOH value.

[0020] The battery pack SOH value detection method provided in this application specifically includes that when the user confirms that the vehicle has a static time of more than 6 hours and the SOC of the power battery pack is greater than 50%, turn on the in-vehicle electrical appliances, such as the refrigerator for refrigeration or heating, and adjust the output current value of the vehicle's DCDC to make the battery pack discharge at a current less than 1C, and finally deplete the power of the small battery pack, that is, the voltage of the battery pack drops to the undervoltage threshold, and the battery pack reports a serious undervoltage alarm; then, control the output current of the vehicle's DCDC to charge the battery pack, limit the charging current to less than 1C, accumulate the remaining power of the battery pack from 0% to 100% of the actual capacity, and obtain the current ambient temperature of the battery pack, and convert the rated capacity of the battery pack at the current ambient temperature into the actual capacity. Specifically, divide the actual capacity by the rated capacity to obtain the true SOH of the battery pack.

[0021] Among them, by controlling the discharge current and charging current of the battery pack, the temperature rise of the battery during the detection process is effectively controlled, avoiding damage to the battery caused by overheating and ensuring the safety of the entire detection process. At the same time, using the in-vehicle electrical appliances (such as the refrigerator) for discharging avoids potential safety hazards that may be brought by external devices. By fully discharging the battery pack to the undervoltage threshold and then fully charging it to 100% SOC, the actual capacity of the battery pack at the current ambient temperature can be accurately measured. This method eliminates the interference of partial discharge or charging on capacity evaluation and improves the accuracy and reliability of SOH calculation. The state of health of the battery is one of the key factors affecting the performance of electric vehicles. By regularly detecting the SOH value, it can be ensured that the battery pack is always in good condition, optimizing the overall performance of the vehicle, including the driving range, power output, etc.

[0022] In the detection method of the present application, a capacity retention rate database of the battery pack at different temperatures is established in advance. This database is generated based on the battery capacity test results under laboratory conditions and covers the performance of the battery pack in a wide temperature range (for example, from -20°C to +50°C). In the database, each temperature point has a corresponding capacity retention rate or correction factor. During the detection process, after the current ambient temperature of the battery pack is recorded, the BMS will query the above temperature-capacity relationship table to find the corresponding temperature correction factor. This correction factor reflects the proportional relationship between the true capacity of the battery at this temperature and the capacity at the reference temperature (such as room temperature 25°C). In addition to the temperature compensation for single detection, the BMS will also integrate historical temperature data to establish a long-term temperature effect model for predicting and compensating the temperature influence that may occur in future detections, further improving the stability of SOH evaluation.

[0023] Please refer to Figure 1 , a method for detecting the SOH value of a battery pack provided by the present application is applicable to a 12V battery pack. The detection method includes: discharging the battery pack until the voltage of the battery pack drops to the undervoltage threshold; charging the battery pack with a first predetermined charge until the battery pack's power is 100%; obtaining the current ambient temperature of the battery pack and the actual capacity of the battery pack at the current ambient temperature, and converting the actual capacity of the battery pack at the current ambient temperature into the rated capacity of the battery pack at the current ambient temperature to obtain the actual SOH value of the battery pack.

[0024] According to the method for detecting the SOH value of the battery pack provided by the present application, by fully discharging the battery pack to the undervoltage threshold and then charging it to the full charge state, the actual capacity of the battery pack at the current ambient temperature can be obtained, so as to calculate the SOH value more accurately and provide accurate information on the state of health of the battery for users and maintenance personnel. Users can actively start the SOH detection function through the central control screen according to the usage situation of the vehicle and the state of the battery pack, or the whole vehicle can automatically start according to preset conditions, increasing the flexibility and convenience of detection.

[0025] During the process of discharging the battery pack, the detection method further includes: the battery pack discharges at a second predetermined charge release current. The second predetermined charge is: 0.8C to 1.2C.

[0026] Adopting a discharge current of 0.8C to 1.2C can ensure that during the deep discharge process of the battery pack, its discharge characteristics can be more fully manifested, avoid the change of the battery pack's own temperature caused by too high discharge charge, help to more accurately evaluate the actual capacity of the battery pack, and thus improve the accuracy of SOH value detection. It avoids over-discharge of the battery or battery damage caused by too high discharge current, and ensures the safety and service life of the battery pack during the detection process.

[0027] In the first embodiment provided by the present application, before discharging the battery pack, the detection method further includes: obtaining the static time of the vehicle and the remaining power of the power battery; judging whether to discharge the battery pack according to the duration of the static time and the remaining power of the power battery.

[0028] Furthermore, before discharging the battery pack, the state of the vehicle's DC-DC converter (DCDC) is synchronously detected to ensure that the converter can operate normally during the subsequent charging process.

[0029] By judging the static time of the vehicle and the remaining power of the power battery, it can be ensured that the battery pack is in a stable and safe state when discharging. Avoiding discharging when the vehicle has just finished driving or the remaining power of the power battery is low can prevent battery thermal runaway or affect the normal start and operation of the vehicle due to insufficient power.

[0030] The confirmation of the static time helps to stabilize the chemical substances inside the battery pack, so as to obtain more accurate and consistent SOH values in the discharge test. The remaining power of the power battery as a reference before discharging can avoid discharging the battery pack at a low SOC (State of Charge), and reduce the calculation error of the SOH value caused by incomplete discharge of the battery. Avoiding discharging under non-ideal conditions reduces unnecessary damage to the battery pack and helps to extend the service life of the battery. Especially when discharging at a relatively high remaining power of the power battery, it can avoid accelerating the aging of the battery pack due to frequent deep discharges.

[0031] The method for judging whether to discharge the battery pack according to the duration of the static time and the remaining power of the power battery includes: automatically discharging the battery pack when the static time is greater than 6 hours and at the same time the remaining power of the power battery is greater than 50%.

[0032] Avoiding deep discharge when the battery SOC is too low can reduce damage to the battery and extend the battery's cycle life. At the same time, the static process also helps the internal chemical reaction of the battery to tend to equilibrium, reduce the internal stress of the battery, and is beneficial to the health of the battery. The 6-hour static time combined with the standard of more than 50% remaining power effectively screens out the most suitable time for SOH testing, avoids unnecessary testing, reduces unnecessary charge and discharge cycles of the battery, and also ensures that the testing process has minimal impact on the user's daily use.

[0033] Automatically determining the discharge timing and starting the test reduces the number of manual steps for the user, making the test process more automated and intelligent, and improving the user experience. In addition, by performing a discharge test when the battery SOC is high, it can ensure that even if the battery is exhausted during the test, there is enough power for the vehicle to use, avoiding the user's range anxiety during the test.

[0034] Setting clear discharge trigger conditions makes the entire detection process more standardized and controllable, helps to establish standardized detection procedures, facilitates replication and implementation in different scenarios and equipment, and improves the reliability and repeatability of detection.

[0035] Through integration with the battery management system (BMS), this technical feature can realize intelligent monitoring of the battery health status, timely identify and perform SOH detection, provide data support for battery health management and maintenance, help prevent potential battery failures, and improve vehicle maintenance efficiency.

[0036] In the second embodiment provided by this application, when the vehicle enters a driving state suitable for regenerative braking, the BMS automatically determines the current SOC (State of Charge) of the battery pack. If the SOC is higher than a preset threshold (such as 50%), and the vehicle is expected to maintain a driving state with available regenerative braking for a long time, the BMS will start the SOH detection program. The BMS controls the battery pack to discharge, and the discharge current is set to a first predetermined charge less than 1C to ensure that the discharge process does not cause excessive stress on the battery. During the discharge process, the voltage, current, and temperature are continuously monitored. Once the data exceeds the normal range, the discharge is immediately stopped to ensure safety. During the discharge process, when the vehicle needs to decelerate or go downhill, the BMS will automatically switch to the regenerative braking mode, convert the kinetic energy of the wheels into electrical energy, and store it in the battery pack to supplement the power of the battery pack until the discharge process to the undervoltage threshold is completed. When the battery pack voltage drops to the undervoltage threshold, the BMS controls the vehicle's charging system and uses the on-board charger or external charging device to charge the battery pack with a charging current less than 1C until the SOC reaches 100%. During the entire discharge and charging process, the BMS records the ambient temperature and actual capacity of the battery pack. After the detection is completed, according to the obtained temperature and capacity data, the true SOH value of the battery pack is obtained by conversion according to the temperature-capacity retention rate. An SOH detection program is preset in the vehicle's battery management system (BMS), and this program can automatically identify the vehicle driving state and the available conditions for regenerative braking. At the same time, the BMS needs to establish communication with the vehicle's driving control system (such as ABS, ESC, etc.) to obtain driving data such as vehicle speed and acceleration. The BMS feeds back the calculated SOH value to the user through the central control screen or mobile application, and the user can understand the health status of the battery pack in real time, providing a basis for subsequent battery maintenance or replacement.

[0037] In this embodiment, the SOH is detected by using the energy recovered by regenerative braking without additional energy consumption, which conforms to the concept of energy conservation and emission reduction. The detection program starts automatically without manual operation by the user, improving the convenience of detection and the user experience; the discharge and charging timing are intelligently judged through driving data, ensuring the safety and accuracy of the detection process.

[0038] The method of discharging the battery pack includes: turning on the electrical appliances in the vehicle that are electrically connected to the battery pack, and the voltage of the electrical appliances is less than or equal to 12V. Using the vehicle's internal 12V electrical appliances as the discharge load can provide a relatively stable discharge environment, ensuring that the battery pack discharges the current according to the preset second predetermined charge (such as 0.8C - 1.2C), avoiding the unstable factors that may be introduced by external discharge devices, and improving the accuracy and repeatability of the SOH value detection.

[0039] This method utilizes the existing electrical resources of the vehicle itself, such as in-vehicle refrigerators, air conditioners, etc., without the need to configure dedicated discharge equipment additionally. This simplifies the detection device, reduces the equipment cost and complexity, and improves the popularity and economy of the detection solution. Users can start the detection program through the vehicle's central control screen or mobile application, and even choose to stop and restore the battery pack to a fully charged state at any time during the discharge process. This design increases the flexibility and convenience of the detection process and meets the user's usage requirements in different scenarios.

[0040] Through the use of built-in electrical appliances, this detection method can adapt to various vehicle environments. Whether in the garage or when parking outside, as long as certain static conditions and SOC levels are met, the SOH value can be detected, improving the feasibility and practicality of the detection.

[0041] The detection method also includes: when the voltage of the battery pack drops to the undervoltage threshold, an undervoltage alarm is issued; then, the battery pack starts to be charged. During the discharge process, when the battery pack reaches the preset undervoltage threshold, the system will automatically stop discharging to prevent irreversible damage caused by over-discharging of the battery, ensuring the safety and health of the battery during the detection process.

[0042] The undervoltage alarm mechanism can timely remind the system and users that the battery pack is about to enter the undervoltage state, and then starting the charging can prevent potential safety risks caused by too low battery voltage, such as damage to the internal structure of the battery or failure of the control circuit. Precise control of the discharge cut-off point and timely charging avoid the battery being in the undervoltage state for a long time, reducing the possibility of the battery accelerating aging due to deep discharge, thus helping to extend the overall service life of the battery.

[0043] Automated alarm and charging start reduce the links that users need to manually intervene. Users only need to start the SOH detection function, and then the discharge, undervoltage detection, and charging processes will all be automatically carried out, improving the user-friendliness of the overall detection process. During the detection process, by precisely controlling the discharge and charging timing, the vehicle's energy management system can be utilized to the maximum extent, reducing the dependence on the main power battery and ensuring more reasonable energy distribution of the vehicle throughout the detection process.

[0044] The first predetermined charge is less than 1C; the detection method also includes: controlling the vehicle's power battery to charge the battery pack with a charge less than 1C. A charging charge less than 1C can effectively control the temperature rise during the charging process, avoid the battery temperature being too high due to rapid charging, and thus reduce the battery performance degradation and safety hazards brought by the thermal effect.

[0045] Low-current charging helps slow down the degradation rate of the internal structure of lithium-ion batteries, prevent overcharging and increased internal pressure caused by high-current charging, thereby extending the battery's service life. By charging at a current less than 1C, the voltage, current, and temperature changes of the battery during charging can be measured more accurately, which is crucial for calculating the actual capacity of the battery pack at the current ambient temperature, thereby improving the accuracy of SOH value detection. The low-current charging mode can be flexibly activated by the user or the entire vehicle according to the standing time and the remaining battery charge. Even during the detection process, the user can interrupt the detection at any time without causing irreversible damage to the battery, ensuring the vehicle's ready availability at all times and enhancing the user experience.

[0046] Furthermore, the detection method further includes: constructing a database of the actual ambient temperature and rated capacity of the battery pack; after obtaining the current ambient temperature of the battery pack, matching it with the database to obtain the rated capacity corresponding to the current ambient temperature.

[0047] After obtaining the current ambient temperature of the battery pack, the BMS can quickly match the temperature-capacity relationship in the database and immediately adjust the SOH calculation logic to ensure rapid response even in an environment with rapid temperature changes, providing immediate and accurate battery status information. This method enables the detection scheme to adapt to a wide range of ambient temperatures. Whether in cold or hot weather, compensation can be made through the corresponding data in the database to ensure that the accuracy of the SOH calculation result is not affected by the external environment, enhancing the environmental adaptability of the detection scheme.

[0048] The database contains the actual capacity data of the battery pack at different ambient temperatures, which enables the SOH detection method to accurately correct the battery capacity according to the real-time temperature, eliminate the influence of temperature changes on capacity assessment, and thus improve the measurement accuracy of the SOH value. After obtaining the current ambient temperature of the battery pack, the BMS can quickly match it with the temperature-capacity relationship in the database and immediately adjust the SOH calculation logic to ensure rapid response even in an environment with rapid temperature changes and provide immediate and accurate battery status information. This method enables the detection scheme to adapt to a wide range of ambient temperatures. Whether in cold or hot weather, compensation can be made through the corresponding data in the database to ensure that the accuracy of the SOH calculation result is not affected by the external environment, enhancing the environmental adaptability of the detection scheme. The application of the database allows the BMS system to continuously optimize battery management strategies based on historical and real-time temperature data, such as charge and discharge control and thermal management system adjustment, to ensure the best performance of the battery pack under different temperature conditions and improve the overall energy efficiency and driving experience of the vehicle. Based on the temperature compensation information in the database, more specific maintenance suggestions can be provided on the maintenance interface at the user end, such as special maintenance guidelines for the battery in extremely cold or hot environments, which helps users take correct maintenance measures to protect the battery health. Constructing a database of the battery pack temperature and rated capacity and applying it to SOH detection significantly improves the accuracy and reliability of SOH detection, enhances the intelligence of the vehicle battery management system and the user's understanding of the battery status, and also provides a strong data basis for the long-term maintenance and performance optimization of the battery.

[0049] The method for detecting the SOH value of the battery pack also includes: SOH = (actual capacity / rated capacity) * 100%. By directly comparing the actual capacity of the battery with the rated capacity, the current health status of the battery can be accurately reflected. This makes the calculation of the SOH (State of Health) value simple and clear, and at the same time ensures the comparability and consistency of the results. As the battery usage time increases, its actual capacity will gradually decrease, while the rated capacity is usually the nominal value when the battery is brand new. Using the above formula to calculate the SOH value can intuitively monitor the degree of battery capacity attenuation, help users timely understand the battery usage status, and predict the timing of replacement or maintenance. Through a single full charge and discharge cycle, the actual capacity data can be directly obtained, and then the SOH value can be calculated. Compared with multiple cycle tests or complex calculation models, this method is more efficient, reducing the detection time and cost.

[0050] The SOH value is an important indicator for evaluating whether the battery needs maintenance or replacement. When the SOH value is lower than a certain threshold, it can prompt the user that the battery performance has significantly declined and consideration should be given to replacement or in-depth maintenance to avoid vehicle stoppage or safety accidents caused by battery failures.

[0051] During the discharge process of the battery pack, the voltage, current, and temperature of the battery pack are obtained at predetermined time intervals; when the voltage, current, or temperature is abnormal, the discharge is stopped. By monitoring the voltage, current, and temperature of the battery pack in real time, abnormal states can be detected in a timely manner, such as too low voltage, too large current, or too high temperature. These abnormalities may be signs of dangerous situations such as internal short circuit or thermal runaway of the battery. Immediately stopping the discharge can prevent these abnormal states from deteriorating further and avoid possible safety accidents such as battery explosion or fire, ensuring the safety of users and vehicles.

[0052] Regularly obtaining the state data of the battery pack helps to more accurately track the discharge process and ensure the integrity and accuracy of the discharge curve. Under normal discharge conditions, the change patterns of voltage and current are predictable, and the temperature should also be maintained within a safe range. The appearance of abnormal data may affect the accuracy of the discharge test. Stopping the discharge and eliminating the abnormality in a timely manner can ensure the accuracy of the subsequent SOH value calculation. Avoiding discharging the battery pack under abnormal conditions can reduce potential damage to the battery. For example, too high temperature will cause the battery performance to decline and the service life to shorten, and too low voltage may damage the internal structure of the battery. By stopping the discharge in a timely manner, the battery pack can be protected from damage and its service life can be extended.

[0053] Abnormal voltage, current, or temperature data are often early warning signals of battery health problems. The abnormal situations found during the detection process can remind users and maintenance personnel of the health status of the battery pack, and take maintenance measures in advance to avoid more serious consequences caused by battery failures, such as sudden power off or the vehicle being unable to start.

[0054] Among them, the abnormality of voltage, current, or temperature includes: the voltage, current, or temperature of the battery pack fluctuates. Under normal conditions, the voltage and current of the battery pack decrease at a predetermined speed, and the temperature is maintained within a certain range. If the voltage and current continue to fluctuate or suddenly decrease, it indicates that the battery pack is abnormal and the discharge should be stopped.

[0055] When the SOH detection function is started, the vehicle owner can be prompted through the central control screen to conduct a battery health detection. If the vehicle needs to be used, the user can click to exit the detection state, and the small battery will return to the full charge state. The BMS adjusts the internal SOH value and reports the corresponding information to the user through the central control screen for use.

[0056] From the above description, it can be seen that the above embodiments of the present invention achieve the following technical effects:

[0057] According to the battery pack SOH value detection method provided by this application, by fully discharging the battery pack to the undervoltage threshold and then charging it to the full charge state, the actual capacity of the battery pack at the current ambient temperature can be obtained, so as to calculate the SOH value more accurately and provide accurate information on the battery health status for users and maintenance personnel. Users can actively start the SOH detection function through the central control screen according to the usage situation of the vehicle and the status of the battery pack, or the whole vehicle can automatically start it according to preset conditions, increasing the flexibility and convenience of detection.

[0058] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to this application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0059] Unless otherwise specifically stated, the relative arrangements of components and steps, numerical expressions, and numerical values set forth in these embodiments do not limit the scope of this application. At the same time, it should be understood that for the convenience of description, the dimensions of the various parts shown in the drawings are not drawn in actual proportional relationships. Technologies, methods, and devices known to those of ordinary skill in the relevant art may not be discussed in detail, but where appropriate, the technologies, methods, and devices should be regarded as part of the specification. In all the examples shown and discussed here, any specific value should be interpreted as merely exemplary and not as a limitation. Therefore, other examples of the exemplary embodiments may have different values. It should be noted that like reference numerals and letters denote like items in the following drawings, and thus, once an item is defined in one drawing, it does not need to be further discussed in subsequent drawings.

[0060] For the convenience of description, spatial relative terms such as "above", "over", "on the upper surface", "upper" can be used herein to describe the spatial positional relationship of a device or feature shown in the figure with other devices or features. It should be understood that the spatial relative terms are intended to include different orientations in use or operation in addition to the orientation described in the figure for the device. For example, if the device in the figure is inverted, the device described as "above" or "over" other devices or structures will then be positioned "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both the orientations of "above" and "below". The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and the corresponding explanations are made for the spatial relative descriptions used herein.

[0061] It should be noted that the terms used herein are for the purpose of describing particular embodiments only and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular forms are also intended to include the plural forms. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, they specify the presence of the features, steps, operations, devices, components, and / or combinations thereof.

[0062] It should be noted that the terms "first", "second", etc. in the description and claims of the present application and the above drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged under appropriate circumstances so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein.

[0063] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A method for detecting the SOH value of a battery pack, applicable to a 12V battery pack, characterized in that, The detection method includes: Discharging the battery pack until the voltage of the battery pack drops to the undervoltage threshold; Charging the battery pack with a first predetermined charge until the battery level of the battery pack reaches 100%; Obtaining the current ambient temperature of the battery pack and the actual capacity of the battery pack at the current ambient temperature, and converting the actual capacity of the battery pack at the current ambient temperature into the rated capacity of the battery pack at the current ambient temperature to obtain the actual SOH value of the battery pack.

2. The method for detecting the SOH value of the battery pack according to claim 1, wherein, During the process of discharging the battery pack, the detection method further includes: The battery pack releases current with a second predetermined charge.

3. The method for detecting the SOH value of the battery pack according to claim 2, wherein The second predetermined charge is: 0.8C to 1.2C.

4. The method for detecting the SOH value of the battery pack according to claim 1, wherein Before discharging the battery pack, the detection method further includes: Obtaining the static time of the vehicle and the remaining power of the power battery; Judging whether to discharge the battery pack according to the duration of the static time and the remaining power of the power battery.

5. The method for detecting the SOH value of the battery pack according to claim 4, wherein The method for judging whether to discharge the battery pack according to the duration of the static time and the remaining power of the power battery includes: When the static time is greater than 6 hours and at the same time the remaining power of the power battery is greater than 50%, automatically discharge the battery pack.

6. The method for detecting the SOH value of the battery pack according to claim 1, wherein The method for discharging the battery pack includes: Turning on the electrical appliance electrically connected to the battery pack in the vehicle, and the voltage of the electrical appliance is less than or equal to 12V.

7. The method for detecting the SOH value of the battery pack according to claim 1, wherein The detection method further includes: When the voltage of the battery pack drops to the undervoltage threshold, an undervoltage alarm is issued; After that, start charging the battery pack.

8. The method for detecting the SOH value of the battery pack according to claim 1, wherein The first predetermined charge is less than 1C; the detection method further includes: Controlling the power battery of the vehicle to charge the battery pack with a charge less than 1C.

9. The method for detecting the SOH value of the battery pack according to claim 1, wherein The detection method further includes: Constructing a database of the actual ambient temperature and rated capacity of the battery pack; After obtaining the current ambient temperature of the battery pack, matching it with the database to obtain the rated capacity corresponding to the current ambient temperature.

10. The method for detecting the SOH value of a battery pack according to claim 1, wherein During the process of discharging the battery pack, the voltage, current and temperature of the battery pack are obtained at intervals of a predetermined time; When the voltage, current or temperature is abnormal, stop discharging.

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