Battery health status estimation method and energy storage system health improvement method

Abstract

The present application provides a battery health status estimation method and an energy storage system health improvement method, wherein the battery health status estimation method includes: when it is determined that the battery pack and the flywheel energy storage device are both in a state to be charged and discharged, controlling the battery pack and the flywheel energy storage device to perform charging and discharging operations simultaneously; in the process of controlling the flywheel energy storage device to perform the charging and discharging operations, obtaining the flywheel charging and discharging parameters of the flywheel energy storage device; and determining the charging and discharging health status of the battery pack according to the flywheel charging and discharging parameters. The health improvement method is to adjust the speed of the flywheel in the flywheel energy storage device to improve the health status of the energy storage system to the rated health status when it is determined that the charging and discharging health status of the battery pack has deteriorated.

Description

Technical Field

[0001] The present application relates to the field of battery technology, and in particular to a method for estimating the health status of a battery and a method for improving the health of an energy storage system. Background Art

[0002] There are usually two major problems in the process of replacing traditional energy generation with new energy generation such as photovoltaic power generation and wind power generation. The first is the cost issue. Whether new energy can achieve higher economic benefits than traditional energy is the basis for the development of the industry. The other problem is the mismatch between new energy generation and power consumption in time and space, which mainly involves power allocation and energy storage. It can be seen that the development of energy storage technology is as important to the new energy industry as "grid parity".

[0003] Chemical batteries, especially lithium batteries, have become the most promising energy storage devices at present due to their high energy density, long service life and low self-discharge rate. Estimation of the state of health (SOH) of batteries is the premise and key to effective battery management. SOH is an estimate of the change in the ability of a battery in use to store and release electrical energy relative to a new battery, and essentially reflects the aging and degradation of the battery. Another parameter of the battery, SOP (state of Power), is very important in some occasions where strict requirements are placed on battery power. SOP is an estimate of the change in the ability of a battery in use to release power relative to a new battery, and also reflects the aging and degradation of the battery.

[0004] Since batteries carry many types of loads and discharge conditions are complex and changeable, it is difficult to achieve real-time monitoring of discharge capacity and discharge power, which places high demands on sensors. At present, common battery health status estimation methods can be divided into model-based methods and data-driven methods. The basic means is to collect relevant data about the battery itself and its use process, establish a mathematical model, and thus estimate the health status of the battery. However, due to the wide variety of batteries, even the same type of batteries from the same manufacturer have different health change patterns due to different production batches, use environments, use conditions, and use time. Therefore, although there are no less than dozens of health prediction methods, there is no recognized and unified method for predicting battery health. Summary of the invention

[0005] The present application provides a battery health status estimation method and an energy storage system health improvement method.

[0006] According to a first aspect of an embodiment of the present application, a battery health status estimation method is provided, which is applied to an energy storage system consisting of a battery pack, a flywheel energy storage device and a management unit; wherein the battery pack is connected in parallel with the flywheel energy storage device, and the management unit controls the battery pack or the flywheel energy storage device to charge and discharge; the method comprises:

[0007] When it is determined that the battery pack and the flywheel energy storage device are both in a state to be charged and discharged, controlling the battery pack and the flywheel energy storage device to perform charging and discharging operations simultaneously;

[0008] In the process of controlling the flywheel energy storage device to perform the charging and discharging operation, obtaining the flywheel charging and discharging parameters of the flywheel energy storage device;

[0009] The charge and discharge health status of the battery pack is determined according to the flywheel charge and discharge parameters.

[0010] According to a second aspect of an embodiment of the present application, a method for improving the health of an energy storage system is provided, wherein the energy storage system comprises a battery pack, a flywheel energy storage device, and a management unit; wherein the battery pack is connected in parallel with the flywheel energy storage device, and the management unit controls the battery pack or the flywheel energy storage device to charge and discharge; the method comprises:

[0011] According to the battery health status estimation method described in the first aspect, determining the charge and discharge health status of the battery pack in the energy storage system;

[0012] When it is determined that the charging and discharging health state of the battery pack has deteriorated, the health state of the energy storage system is improved to a rated health state by adjusting the rotation speed of the flywheel in the flywheel energy storage device.

[0013] According to a third aspect of an embodiment of the present application, there is provided an energy storage system, comprising a battery pack, a flywheel energy storage device and a management unit; wherein the battery pack is connected in parallel with the flywheel energy storage device, and the management unit controls the battery pack or the flywheel energy storage device to charge and discharge; the energy storage system is used to implement the battery health status estimation method described in the first aspect, or to implement the energy storage system health improvement method described in the second aspect.

[0014] According to a fourth aspect of an embodiment of the present application, a computer device is provided, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the program, the battery health status estimation method described in the first aspect is implemented, or the method for improving the health of the energy storage system described in the second aspect is implemented.

[0015] According to a fifth aspect of an embodiment of the present application, a computer-readable storage medium is provided, on which a computer program is stored. When the program is executed by a processor, the battery health status estimation method described in the first aspect is implemented, or it is used to implement the energy storage system health improvement method described in the second aspect.

[0016] According to a sixth aspect of an embodiment of the present application, a computer program product is provided, comprising a computer program, which, when executed by a processor, implements the battery health status estimation method described in the first aspect, or is used to implement the energy storage system health improvement method described in the second aspect.

[0017] In the embodiment of the present application, a flywheel energy storage device is used as a sensor, which is connected in parallel with a battery pack to form an energy storage system. Each charging and discharging is an opportunity to evaluate the health status of the battery pack. In this way, the evaluation is performed during the actual operation process, the evaluation is more accurate, and it also complies with the basic principle of online real-time evaluation.

[0018] It is to be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0020] Figure 1 is a flow chart of a battery health status estimation method according to an exemplary embodiment;

[0021] Figure 2 is a schematic diagram of an energy storage system according to an exemplary embodiment;

[0022] Figure 3 is a flow chart of a method for determining a discharge capacity health level according to an exemplary embodiment;

[0023] Figure 4 is a flow chart of a method for determining discharge power health according to an exemplary embodiment;

[0024] Figure 5 is a flow chart of a method for improving the health of an energy storage system according to an exemplary embodiment;

[0025] Figure 6 The diagram is a schematic structural diagram of a computer device according to an exemplary embodiment. DETAILED DESCRIPTION

[0026] Exemplary embodiments will be described in detail herein, examples of which are shown in the accompanying drawings. When the following description refers to the drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The specific methods described in the following exemplary embodiments do not represent all schemes consistent with the present application. Instead, they are only examples of devices and methods consistent with some aspects of the present application as detailed in the attached claims.

[0027] The terms used in this application are for the purpose of describing specific embodiments only and are not intended to limit this application. The singular forms of "a", "said" and "the" used in this application and the appended claims are also intended to include plural forms unless the context clearly indicates other meanings. It should also be understood that the term "and / or" used herein refers to and includes any or all possible combinations of one or more associated listed items.

[0028] It should be understood that although the terms first, second, third, etc. may be used in the present application to describe various information, these information should not be limited to these terms. These terms are only used to distinguish the same type of information from each other. For example, without departing from the scope of the present application, the first information may also be referred to as the second information, and similarly, the second information may also be referred to as the first information. Depending on the context, the word "if" as used herein may be interpreted as "at the time of" or "when" or "in response to determining".

[0029] In order to make the battery health status estimation method provided by the present application clearer, the execution process of the scheme provided by the present application is described in detail below in combination with the accompanying drawings and specific embodiments.

[0030] See also Figure 1 , Figure 1 This is a flow chart of a battery health status estimation method shown in an embodiment provided by the present application. The method is applied to an energy storage system consisting of a battery pack, a flywheel energy storage device and a management unit; wherein the battery pack is connected in parallel with the flywheel energy storage device, and the management unit controls the battery pack or the flywheel energy storage device to charge and discharge.

[0031] In one possible implementation, Figure 2An energy storage system shown includes a battery pack 201, a flywheel energy storage device 202 and a management unit 203. The management unit 203 may be a system management system (SMS) or a battery management system (BMS), and the SMS or BMS manages the charging and discharging of the battery pack 201 and the flywheel energy storage device 202. Optionally, the energy storage system may record and display different parameters on the control panel. For example, system parameters include: system power, system capacity, etc.; battery pack parameters include: battery power, battery capacity, battery health status, etc.; flywheel parameters include: flywheel speed, flywheel speed change information, flywheel speed change rate, etc.

[0032] like Figure 1 As shown, the battery health status estimation method process includes steps 101 to 103.

[0033] Step 101, when it is determined that the battery pack and the flywheel energy storage device are both in a state to be charged and discharged, control the battery pack and the flywheel energy storage device to perform charging and discharging operations simultaneously.

[0034] In the embodiment of the present application, the state to be charged and discharged is a working state of a battery pack or a flywheel energy storage device in the energy storage system. For example, when the battery pack or the flywheel energy storage device is fully charged, it can be considered that the battery pack or the flywheel energy storage device is in a state to be discharged; on the contrary, when the battery pack or the flywheel energy storage device is out of power, it can be considered that the battery pack or the flywheel energy storage device is in a state to be charged.

[0035] In this step, when it is determined that both the battery pack and the flywheel energy storage device are in a state to be charged and discharged, the battery pack and the flywheel energy storage device can be controlled to perform charging and discharging operations simultaneously. For example, the control unit can control the battery pack and the flywheel energy storage device to perform charging operations simultaneously when it is determined that both the battery pack and the flywheel energy storage device are in a state to be charged; or control the battery pack and the flywheel energy storage device to perform discharging operations simultaneously when it is determined that both the battery pack and the flywheel energy storage device are in a state to be discharged.

[0036] Step 102: acquiring the flywheel charge and discharge parameters of the flywheel energy storage device during the process of controlling the flywheel energy storage device to perform the charge and discharge operation.

[0037] For example, in the process of controlling the flywheel energy storage device to perform a charging operation, the flywheel charging parameters of the flywheel energy storage device are obtained; or, in the process of controlling the flywheel energy storage device to perform a discharging operation, the flywheel discharging parameters of the flywheel energy storage device are obtained.

[0038] Step 103: determining the charge and discharge health status of the battery pack according to the flywheel charge and discharge parameters.

[0039] After obtaining the flywheel charge and discharge parameters of the flywheel energy storage device, this step can determine the charge and discharge health status of the battery pack according to the flywheel charge and discharge parameters.

[0040] In the embodiment of the present application, the flywheel energy storage device is used as a sensor. The flywheel energy storage device is connected in parallel to the battery pack to form an overall energy storage system. The health status of the battery can be inferred from the working characteristics of the flywheel energy storage device.

[0041] As a mechanical device, the flywheel energy storage device has a very slow health degradation rate. The number of charge and discharge times is at least one order of magnitude higher than that of chemical batteries, which is only several thousand times. Compared with the health degradation rate of chemical batteries, the degradation rate of flywheel energy storage devices can be basically ignored. In the energy storage system connected in parallel with the battery pack, it can be assumed that the health status of the flywheel remains unchanged. In addition, the health status of the flywheel energy storage device can be accurately determined by very simple parameters. Its energy storage capacity and power are uniquely determined by the speed of the flywheel.

[0042] Therefore, for the energy storage system composed of a battery pack and a flywheel energy storage device in parallel, during discharge, for the same load, since the health status of the flywheel energy storage device is unchanged, the characteristic changes of the flywheel energy storage device discharge are caused by the characteristic changes of the battery pack (including the health status and external environmental influences, etc.); the health status of the battery pack can be inferred from the characteristic changes of the flywheel energy storage device; and the characteristic changes of the flywheel energy storage device can be accurately described by a very simple parameter (rotation speed).

[0043] Similarly, during each charging, the charging system and charging strategy remain unchanged. Since the health status of the flywheel energy storage device is unchanged, the characteristic changes of the flywheel energy storage device charging are caused by the characteristic changes of the battery pack (including health status and external environment, etc.). The charging health status of the battery pack can be inferred from the characteristic changes (rotation speed) of the flywheel energy storage device.

[0044] The flywheel energy storage device is used as a sensor and connected in parallel with the battery pack to form an energy storage system. Each charge and discharge is an opportunity to evaluate the health status of the battery pack. This way, the evaluation is performed during the actual operation process, which is more accurate and conforms to the basic principle of online real-time evaluation.

[0045] In addition, the flywheel energy storage device also acts as an optimizer. According to the degree of decline in the health status of the battery pack and the amount of power and capacity attenuation, the flywheel can increase the corresponding power and capacity by increasing the rotation speed, thereby ensuring that the health status (capacity and power) of the entire system remains unchanged.

[0046] In some optional embodiments, the state to be charged and discharged includes a state to be discharged; the charging and discharging operation includes a discharging operation; the flywheel charging and discharging parameters include flywheel discharge parameters; and the charging and discharging health state of the battery pack is determined based on the flywheel charging and discharging parameters, that is, step 103 includes: determining the discharge health state of the battery pack based on the flywheel discharge parameters.

[0047] In some optional embodiments, the flywheel discharge parameter includes a flywheel discharge capacity; the discharge health state of the battery pack is determined according to the flywheel discharge parameter, such as Figure 3 As shown, step 301 and step 302 may be included.

[0048] Step 301, subtracting the flywheel discharge capacity from the total discharge capacity of the energy storage system to obtain the battery discharge capacity of the battery pack;

[0049] Step 302: taking the ratio of the discharge capacity of the battery to the rated discharge capacity of the battery pack as the discharge capacity health of the battery pack.

[0050] In the above optional embodiment, in step 301, the battery discharge capacity of the battery pack can be calculated according to the following formula:

[0051] C_batt=C_total–C_fw

[0052] Among them, C_total is the total discharge capacity of the energy storage system; C_fw is the flywheel discharge capacity; C_batt is the battery discharge capacity of the battery pack. After obtaining the battery discharge capacity of the battery pack, the discharge capacity health of the battery pack can be calculated according to the following formula:

[0053] SOH=C_batt_now / C_batt_rate

[0054] Among them, C_batt_now is the current battery discharge capacity of the battery pack; C_batt_rate is the rated discharge capacity of the battery pack; SOH is the discharge capacity health of the battery pack.

[0055] In some optional embodiments, the flywheel discharge parameters include a flywheel initial speed and a flywheel cut-off speed; the method further includes: determining the flywheel discharge capacity according to the flywheel initial speed and the flywheel cut-off speed.

[0056] In the above optional embodiment, the flywheel discharge capacity can be calculated according to the following formula:

[0057] C_fw=k(V0^2–V1^2)

[0058] Among them, V0 is the initial speed of the flywheel; V1 is the cut-off speed of the flywheel; C_fw is the discharge capacity of the flywheel; k is a constant.

[0059] In some optional embodiments, the flywheel discharge parameters include the discharge voltage, discharge current and discharge time of the flywheel energy storage device during the discharge operation; the method also includes: determining the flywheel discharge capacity based on the discharge voltage, discharge current and discharge time.

[0060] In the above optional embodiment, during the discharge operation of the flywheel energy storage device, the discharge voltage, discharge current and discharge time can be directly obtained, so that the flywheel discharge capacity can be calculated according to the following formula:

[0061] C_fw=V*I*t

[0062] Wherein, C_fw is the flywheel discharge capacity; V is the discharge voltage; I is the discharge current; t is the discharge time.

[0063] In some optional embodiments, the flywheel discharge parameter includes a flywheel discharge power; the discharge health state of the battery pack is determined according to the flywheel discharge parameter, such as Figure 4 As shown, step 401 and step 402 may be included.

[0064] Step 401, subtracting the flywheel discharge power from the total discharge power of the energy storage system to obtain the battery discharge power of the battery pack;

[0065] Step 402: The ratio of the battery discharge power to the rated discharge power of the battery pack is used as the discharge power health of the battery pack.

[0066] In some occasions where power requirements are more important, it is generally necessary to estimate the health status of the battery power. In the above optional embodiment, the battery discharge power of the battery pack can be calculated according to the following formula in step 401:

[0067] P_batt=P_total–P_fw

[0068] Among them, P_batt is the battery discharge power; P_total is the total discharge power of the energy storage system; P_fw is the flywheel discharge power.

[0069] After obtaining the battery discharge power, the discharge power health of the battery pack can be calculated according to the following formula:

[0070] SOP=P_now / P_rated

[0071] Among them, SOP is the discharge power health of the battery pack; P_now is the current battery discharge power of the battery pack; P_rated is the rated discharge power of the battery pack. SOP indicates the power degradation level of the battery pack.

[0072] In some optional embodiments, the flywheel discharge parameter includes a flywheel speed change curve; the method further includes: determining the flywheel discharge power according to the flywheel speed change curve.

[0073] In some optional embodiments, the flywheel discharge parameters include a flywheel initial speed and a flywheel cut-off speed; the method further includes: determining the flywheel discharge power according to the flywheel initial speed and the flywheel cut-off speed.

[0074] In the above optional embodiment, the flywheel discharge power can be calculated according to the following formula:

[0075] P_fw=d(C_fw) / dt=d(k(V0^2–V1^2)) / dt

[0076] Among them, P_fw is the flywheel discharge power; C_fw is the flywheel discharge capacity; V0 is the initial speed of the flywheel; V1 is the speed during the flywheel discharge, V1 decreases with the discharge time, and forms a speed change curve with it. Power is the rate of change of energy. For a flywheel energy storage device, the flywheel discharge power is the rate of change of the flywheel discharge capacity. Therefore, the flywheel discharge capacity can be calculated based on the speed change curve of the flywheel energy storage device, thereby obtaining the flywheel discharge power.

[0077] In many cases, the flywheel discharge power can also be estimated by the flywheel cutoff speed; the discharge power is directly related to the discharge cutoff voltage, and the cutoff voltage is directly related to the flywheel cutoff speed, so the flywheel discharge power is directly related to the flywheel cutoff speed.

[0078] In the above optional embodiment, the flywheel discharge power can be calculated according to the following formula:

[0079] P_fw=k*V1

[0080] Among them, V1 is the flywheel cut-off speed; k is a constant.

[0081] In many cases, some parameters of the flywheel energy storage device during the discharge operation can be directly obtained, such as the discharge voltage and the discharge current. In some optional embodiments, the flywheel discharge parameters include the discharge voltage and the discharge current of the flywheel energy storage device during the discharge operation; the method further includes: taking the product of the discharge voltage and the discharge current as the flywheel discharge power.

[0082] In the above optional embodiment, the flywheel discharge power can be calculated according to the following formula:

[0083] P_fw=V*I

[0084] Among them, V is the discharge voltage; I is the discharge current.

[0085] The above scheme for estimating the discharge health state of the battery pack is introduced in detail. In the above embodiment, the same load can be discharged simultaneously when the flywheel energy storage device and the battery pack are both fully charged, and the flywheel discharge parameters are obtained during the discharge process of the flywheel energy storage device. The discharge characteristics of the battery pack are calculated based on the flywheel discharge parameters, and the health state of the battery pack during discharge is estimated.

[0086] Since the health of the flywheel energy storage device remains unchanged, under the condition of unchanged charging power, the flywheel energy storage device is fully charged, and the charging time each time remains fixed. When the flywheel energy storage device and the battery pack are charged at the same time using the same charging device, if the charging time of the flywheel energy storage device is different each time, then this difference must be caused by the different charging power of the battery pack. The fundamental reason is that the health of the battery pack has changed. Therefore, the health status of the battery pack can be estimated based on the charging status of the flywheel energy storage device.

[0087] In some optional embodiments, the state to be charged and discharged includes a state to be charged; the charging and discharging operation includes a charging operation; the flywheel charging and discharging parameters include flywheel charging parameters; wherein the flywheel charging parameters include flywheel charging power; the charge and discharge health state of the battery pack is determined based on the flywheel charging and discharging parameters, that is, step 103 includes: using the total charging power of the energy storage system minus the flywheel charging power to obtain the battery charging power of the battery pack.

[0088] In the above optional embodiment, the battery charging power can be calculated according to the following formula:

[0089] P_batt=P_total–P_fw

[0090] Wherein, P_total is the total charging power of the energy storage system; P_fw is the flywheel charging power. In a possible implementation, the total charging power of the energy storage system and the flywheel charging power can be automatically recorded by the energy storage system.

[0091] In some optional embodiments, the flywheel charging parameters include flywheel charging time and flywheel charging capacity; the method further includes: taking the ratio of the flywheel charging capacity to the flywheel charging time as the flywheel charging power.

[0092] In the above optional embodiment, the flywheel charging power can be calculated according to the following formula:

[0093] P_fw=C_fw / T_fw

[0094] Among them, C_fw is the flywheel charging capacity; T_fw is the flywheel charging time.

[0095] The above scheme for estimating the charging health state of the battery pack is introduced in detail. In the above embodiment, when the flywheel energy storage device and the battery pack are both in a state of needing to be charged, they can be charged simultaneously with the same charging device. The flywheel energy storage device obtains the flywheel charging parameters during the charging process, and then uses the above flywheel charging parameters to calculate the charging characteristics of the battery pack, thereby estimating the health state of the battery pack during charging.

[0096] In the embodiment of the present application, the energy storage system includes a battery pack, a flywheel energy storage device and a management unit; wherein the battery pack is connected in parallel with the flywheel energy storage device, and the management unit controls the battery pack or the flywheel energy storage device to charge and discharge. Figure 2 As shown, the energy storage system includes a battery pack 201, a flywheel energy storage device 202 and a management unit 203. The management unit 203 may be a system management system (SMS) or a battery management system (BMS), and the SMS or BMS manages the charging and discharging of the battery pack 201 and the flywheel energy storage device 202.

[0097] The present application also provides a method for improving the health of the energy storage system, such as Figure 5 As shown, step 501 and step 502 may be included.

[0098] Step 501, determining the charge and discharge health status of the battery pack in the energy storage system according to the battery health status estimation method described in any embodiment of the present application;

[0099] Step 502: When it is determined that the charge and discharge health state of the battery pack has deteriorated, the rotation speed of the flywheel in the flywheel energy storage device is adjusted to improve the health state of the energy storage system to a rated health state.

[0100] In the above embodiment, when it is determined that the charging health state of the battery pack has deteriorated, the speed of the flywheel in the flywheel energy storage device can be adjusted to improve the health state of the entire energy storage system to the rated health state. For example, when it is determined that the battery discharge capacity of the battery pack is lower than the rated discharge capacity, the speed of the flywheel can be increased so that the total discharge capacity of the entire energy storage system is the same as the rated discharge capacity. When the battery discharge power of the battery pack is lower than the rated discharge power, it is similar to this and will not be repeated here.

[0101] In the embodiment of the present application, the speed of the flywheel in the flywheel energy storage device can be adjusted to improve the health state of the entire energy storage system to the rated health state when the charge and discharge health state of the battery pack deteriorates. For example, by adjusting the speed of the flywheel, the capacity and power of the flywheel energy storage device can be increased to compensate for the decrease in the capacity and power of the battery, thereby ensuring that the entire energy storage system remains at its original health level.

[0102] The total discharge capacity of the energy storage system is equal to the sum of the battery discharge capacity of the battery pack and the flywheel discharge capacity of the flywheel energy storage device. The specific formula is as follows:

[0103] C_total_now=C_fw_now+C_bat_now

[0104] Among them, C_total_now is the current total discharge capacity of the energy storage system; C_fw_now is the current flywheel discharge capacity of the flywheel energy storage device; C_bat_now is the current battery discharge capacity of the battery pack.

[0105] In the entire energy storage system, the battery discharge capacity of the battery pack may decrease. For example, the battery discharge capacity of the battery pack may be lower than the rated discharge capacity of the battery pack, which indicates that the discharge health of the battery pack has deteriorated. In order to ensure that the total discharge capacity of the entire energy storage system does not decrease, the flywheel discharge capacity of the flywheel energy storage device can be increased, for example, by increasing the speed of the flywheel.

[0106] In some optional embodiments, the charge and discharge health status includes a battery discharge capacity;

[0107] The method of adjusting the rotation speed of the flywheel in the flywheel energy storage device to improve the health state of the energy storage system to a rated health state includes:

[0108] The flywheel target discharge capacity of the flywheel energy storage device is obtained by subtracting the battery discharge capacity from the rated discharge capacity of the energy storage system;

[0109] According to the flywheel target discharge capacity, the flywheel initial speed and the flywheel cutoff speed of the flywheel in the flywheel energy storage device are determined so that the actual discharge capacity of the energy storage system is consistent with the rated discharge capacity.

[0110] In the above optional embodiment, the flywheel target discharge capacity of the flywheel energy storage device can be obtained according to the following formula:

[0111] C_fw_target=C_total__rate–C_bat_now

[0112] Among them, C_total__rate is the rated discharge capacity of the energy storage system; C_bat_now is the current battery discharge capacity of the battery pack; and C_fw_target is the flywheel target discharge capacity of the energy storage device.

[0113] The flywheel cut-off speed of the flywheel in the flywheel energy storage device is obtained according to the following formula:

[0114] V1=Sqrt(V0^2-C_fw_target / k)

[0115] Among them, V1 is the flywheel cut-off speed; V0 is the flywheel initial speed; C_fw_target is the flywheel target discharge capacity; k is a constant.

[0116] In the above optional embodiment, even if the battery discharge capacity of the battery pack decreases, the flywheel discharge capacity of the flywheel energy storage device can be increased accordingly, thereby ensuring that the total discharge capacity of the entire energy storage system remains unchanged and the system health does not decrease; in addition, increasing the flywheel discharge capacity of the flywheel energy storage device can avoid damage to the battery due to excessive discharge of the battery pack.

[0117] Furthermore, if multiple energy storage systems are connected in series and parallel to form a larger energy storage system, in this larger energy storage system, when discharging, the charge and discharge capacity of the subsystems remains unchanged, and the balance between the subsystems can be guaranteed.

[0118] In some optional embodiments, the charge and discharge health status includes battery discharge power;

[0119] The method of adjusting the rotation speed of the flywheel in the flywheel energy storage device to improve the health state of the energy storage system to a rated health state includes:

[0120] The flywheel target discharge power of the flywheel energy storage device is obtained by subtracting the battery discharge power from the rated discharge power of the energy storage system;

[0121] According to the flywheel target discharge power, the flywheel initial speed and the flywheel cutoff speed of the flywheel in the flywheel energy storage device are determined so that the actual discharge power of the energy storage system is consistent with the rated discharge power.

[0122] In the above optional embodiment, the flywheel target discharge power of the flywheel energy storage device can be obtained according to the following formula:

[0123] P_fw_target=P_total__rate–P_bat_now

[0124] Among them, P_total__rate is the rated discharge power of the energy storage system; P_bat_now is the current battery discharge power of the battery pack; and P_fw_target is the flywheel target discharge power of the energy storage device.

[0125] The initial speed of the flywheel in the flywheel energy storage device is obtained according to the following formula:

[0126] V=P_fw_target / k

[0127] Wherein, V is the initial speed of the flywheel; P_fw_target is the target discharge power of the flywheel; k is a constant or a constant table (obtained based on actual tests).

[0128] In the above optional embodiment, even if the battery discharge power of the battery pack decreases, the flywheel discharge power of the flywheel energy storage device can be increased accordingly, thereby ensuring that the total discharge power of the entire energy storage system remains unchanged and the system health does not decrease.

[0129] In some optional embodiments, the method further includes: adjusting the charging speed of the battery pack by adjusting the flywheel charging speed of the flywheel energy storage device. According to the above measured charging health state of the battery pack, the charging speed of the battery pack can be adjusted by adjusting the charging speed of the flywheel energy storage device, so that the battery pack is charged at an optimized charging speed, ensuring that the entire energy storage system remains at its original health level.

[0130] The present application also provides a computer device, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the program, the battery health status estimation method or energy storage system health improvement method of any embodiment of the present application can be implemented.

[0131] Figure 6 A more specific hardware structure diagram of a computer device provided in an embodiment of the present application is shown, and the device may include: a processor 1010, a memory 1020, an input / output interface 1030, a communication interface 1040, and a bus 1050. The processor 1010, the memory 1020, the input / output interface 1030, and the communication interface 1040 are connected to each other through the bus 1050 in the device.

[0132] The processor 1010 can be implemented by a general-purpose CPU (Central Processing Unit), a microprocessor, an application-specific integrated circuit (ASIC), or one or more integrated circuits, and is used to execute relevant programs to implement the technical solutions provided in the embodiments of this specification.

[0133] The memory 1020 may be implemented in the form of ROM (Read Only Memory), RAM (Random Access Memory), static storage device, dynamic storage device, etc. The memory 1020 may store an operating system and other application programs. When the technical solutions provided in the embodiments of this specification are implemented by software or firmware, the relevant program codes are stored in the memory 1020 and are called and executed by the processor 1010.

[0134] The input / output interface 1030 is used to connect the input / output module to realize information input and output. The input / output module can be configured in the device as a component (not shown in the figure), or it can be externally connected to the device to provide corresponding functions. The input device may include a keyboard, a mouse, a touch screen, a microphone, various sensors, etc., and the output device may include a display, a speaker, a vibrator, an indicator light, etc.

[0135] The communication interface 1040 is used to connect a communication module (not shown) to realize communication interaction between the device and other devices. The communication module can realize communication through a wired mode (such as USB, network cable, etc.) or a wireless mode (such as mobile network, WIFI, Bluetooth, etc.).

[0136] The bus 1050 includes a path that transmits information between the various components of the device (eg, the processor 1010, the memory 1020, the input / output interface 1030, and the communication interface 1040).

[0137] It should be noted that, although the above device only shows the processor 1010, the memory 1020, the input / output interface 1030, the communication interface 1040 and the bus 1050, in the specific implementation process, the device may also include other components necessary for normal operation. In addition, it can be understood by those skilled in the art that the above device may also only include the components necessary for implementing the embodiments of the present specification, and does not necessarily include all the components shown in the figure.

[0138] The present application also provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, can implement the battery health status estimation method or energy storage system health improvement method of any embodiment of the present application.

[0139] The non-temporary computer-readable storage medium may be a ROM, a random access memory (RAM), a CD-ROM, a magnetic tape, a floppy disk, an optical data storage device, etc., and the present application does not limit this.

[0140] In some optional embodiments, the embodiments of the present application provide a computer program product, including computer readable code, when the computer readable code is run on a device, the processor in the device executes the method for estimating the battery health state or the method for improving the health of the energy storage system provided in any of the above embodiments. The computer program product can be implemented in hardware, software or a combination thereof.

[0141] Those skilled in the art will readily appreciate other embodiments of the present application after considering the specification and practicing the inventions claimed herein. The present application is intended to cover any variations, uses or adaptations of the present application, which follow the general principles of the present application and include common knowledge or customary techniques in the art that are not claimed in the present application. The specification and examples are intended to be exemplary only, and the true scope and spirit of the present application are indicated by the following claims.

[0142] It should be understood that the present application is not limited to the precise structures that have been described above and shown in the drawings, and that various modifications and changes may be made without departing from the scope thereof. The scope of the present application is limited only by the appended claims.

[0143] The above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present application should be included in the scope of protection of the present application.

Claims

1. A method for estimating a battery health state, characterized in that: Applicable to an energy storage system consisting of a battery pack, a flywheel energy storage device and a management unit; wherein the battery pack is connected in parallel with the flywheel energy storage device, and the management unit controls the battery pack or the flywheel energy storage device to charge and discharge; the method comprises: When it is determined that both the battery pack and the flywheel energy storage device are in a state to be charged and discharged, controlling the battery pack and the flywheel energy storage device to perform charging and discharging operations simultaneously, wherein the state to be charged and discharged includes a state to be discharged, and the charging and discharging operations include a discharging operation; In the process of controlling the flywheel energy storage device to perform the charge and discharge operation, obtaining the flywheel charge and discharge parameters of the flywheel energy storage device, wherein the flywheel charge and discharge parameters include flywheel discharge parameters, and the flywheel discharge parameters include flywheel discharge capacity; The charge and discharge health status of the battery pack is determined according to the flywheel charge and discharge parameters, including subtracting the flywheel discharge capacity from the total discharge capacity of the energy storage system to obtain the battery discharge capacity of the battery pack, and taking the ratio of the battery discharge capacity to the rated discharge capacity of the battery pack as the discharge capacity health status of the battery pack.

2. The method according to claim 1, characterized in that The flywheel discharge parameters include the flywheel initial speed and the flywheel cut-off speed; the method further includes: The flywheel discharge capacity is determined according to the flywheel initial speed and the flywheel cut-off speed.

3. The method according to claim 1, characterized in that The flywheel discharge parameters include the discharge voltage, discharge current and discharge time of the flywheel energy storage device during the discharge operation; The method further comprises: The flywheel discharge capacity is determined according to the discharge voltage, discharge current and discharge time.

4. The method according to claim 1, characterized in that: The flywheel discharge parameter includes a flywheel discharge power; and determining the discharge health state of the battery pack according to the flywheel discharge parameter includes: The battery discharge power of the battery pack is obtained by subtracting the flywheel discharge power from the total discharge power of the energy storage system; The ratio of the battery discharge power to the rated discharge power of the battery pack is used as the discharge power health of the battery pack.

5. The method according to claim 4, characterized in that The flywheel discharge parameter includes a flywheel speed change curve; the method further includes: The flywheel discharge power is determined according to the flywheel speed variation curve.

6. The method according to claim 4, characterized in that The flywheel discharge parameters include the flywheel initial speed and the flywheel cut-off speed; the method further includes: The flywheel discharge power is determined according to the flywheel initial speed and the flywheel cut-off speed.

7. The method according to claim 4, characterized in that The flywheel discharge parameters include the discharge voltage and discharge current of the flywheel energy storage device during the discharge operation; the method further includes: The product of the discharge voltage and the discharge current is used as the flywheel discharge power.

8. The method according to claim 1, characterized in that The state to be charged and discharged includes a state to be charged; the charging and discharging operation includes a charging operation; the flywheel charging and discharging parameter includes a flywheel charging parameter; wherein the flywheel charging parameter includes a flywheel charging power; Determining the charge and discharge health status of the battery pack according to the flywheel charge and discharge parameters includes: The battery charging power of the battery pack is obtained by subtracting the flywheel charging power from the total charging power of the energy storage system.

9. The method according to claim 8, characterized in that The flywheel charging parameters include flywheel charging time and flywheel charging capacity; the method further includes: The ratio of the flywheel charging capacity to the flywheel charging time is used as the flywheel charging power.

10. A method for improving the health of an energy storage system, characterized in that: The energy storage system comprises a battery pack, a flywheel energy storage device and a management unit; wherein the battery pack is connected in parallel with the flywheel energy storage device, and the management unit controls the battery pack or the flywheel energy storage device to charge and discharge; the method comprises: According to the battery health status estimation method according to any one of claims 1 to 9, determining the charge and discharge health status of the battery pack in the energy storage system; When it is determined that the charging and discharging health state of the battery pack has deteriorated, the health state of the energy storage system is improved to a rated health state by adjusting the rotation speed of the flywheel in the flywheel energy storage device.

11. The method according to claim 10, characterized in that The charge and discharge health status includes the battery discharge capacity; The method of adjusting the rotation speed of the flywheel in the flywheel energy storage device to improve the health state of the energy storage system to a rated health state includes: The flywheel target discharge capacity of the flywheel energy storage device is obtained by subtracting the battery discharge capacity from the rated discharge capacity of the energy storage system; According to the flywheel target discharge capacity, the flywheel initial speed and the flywheel cutoff speed of the flywheel in the flywheel energy storage device are determined so that the actual discharge capacity of the energy storage system is consistent with the rated discharge capacity.

12. The method according to claim 10, characterized in that The charge and discharge health status includes battery discharge power; The method of adjusting the rotation speed of the flywheel in the flywheel energy storage device to improve the health state of the energy storage system to a rated health state includes: The flywheel target discharge power of the flywheel energy storage device is obtained by subtracting the battery discharge power from the rated discharge power of the energy storage system; According to the flywheel target discharge power, the flywheel initial speed and the cut-off speed of the flywheel in the flywheel energy storage device are determined so that the actual discharge power of the energy storage system is consistent with the rated discharge power.

13. The method according to claim 10, characterized in that The method further comprises: The charging speed of the battery pack is adjusted by adjusting the flywheel charging speed of the flywheel energy storage device.

14. An energy storage system, characterized in that: The energy storage system includes a battery pack, a flywheel energy storage device and a management unit; wherein the battery pack is connected in parallel with the flywheel energy storage device, and the management unit controls the battery pack or the flywheel energy storage device to charge and discharge; the energy storage system is used to implement the battery health status estimation method as described in any one of claims 1 to 9, or to implement the energy storage system health improvement method as described in any one of claims 10 to 13.

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