Method for evaluating state of health of battery pack

Abstract

The invention discloses a method for evaluating the health state of a battery pack, and the battery pack comprises a housing; the plurality of battery cells are accommodated in the shell; the electric tool interface is arranged on the shell; the first circuit board is contained in the shell and electrically connected with the electric tool interface, and a first controller is arranged on the first circuit board; the health state evaluation method comprises the steps of estimating an interval health state of a battery pack in a preset voltage interval in a charging process of the battery pack; and determining the overall health state of the battery pack according to the interval health state and a preset mapping model. According to the technical scheme, the overall health state is evaluated through the interval health state of the battery pack, it is not required that the health state of the battery pack is evaluated in a complete charging and / or discharging period, and the evaluation condition is easier to achieve.

Description

Technical Field

[0001] The present application relates to the technical field of electric tools, and in particular to a method for evaluating the health status of a battery pack. Background Art

[0002] The battery packs in power tools have various capacities based on the battery type, number of batteries, and battery health status. The charge and discharge speeds and powers of the battery packs also vary based on the battery pack capacity, load size, charger characteristics, and usage environment. As batteries age, their capacity gradually decays and their internal resistance slowly increases. Conventional methods fully charge and / or fully discharge the battery to obtain the maximum charge / discharge capacity, or maximum chemical capacity, of the battery within a complete charge and / or discharge cycle. Conventional methods typically require a stable current within this complete charge and / or discharge cycle, and the experimental conditions are relatively harsh, which may not always be met during daily use.

[0003] This section provides background information related to the present application which is not necessarily prior art. Summary of the Invention

[0004] One object of the present application is to solve or at least alleviate part or all of the above problems. To this end, one object of the present application is to provide a method for evaluating the health status of a battery pack.

[0005] In order to achieve the above objectives, this application adopts the following technical solutions: The present application provides a method for evaluating the health status of a battery pack, wherein the battery pack includes: a shell; a plurality of battery cells accommodated in the shell; a power tool interface arranged in the shell; and a first circuit board accommodated in the shell and electrically connected to the power tool interface, wherein a first controller is arranged on the first circuit board; the evaluation method includes: estimating the interval health status of the battery pack within a preset voltage range during the charging process of the battery pack; and determining the overall health status of the battery pack based on the interval health status and a preset mapping model.

[0006] In one embodiment, the method for evaluating the health status of the battery pack further includes: obtaining the voltage of the battery pack after a preset time period of starting charging, and if the voltage is less than the minimum value within the preset voltage range, estimating the interval health status while the charging voltage is within the preset voltage range.

[0007] In one embodiment, the method for evaluating the health status of the battery pack further includes: obtaining the voltage of the battery pack after a preset time period of starting charging, and if the charging voltage is greater than or equal to the minimum value within the preset voltage range, the interval health status is not estimated during this charging process.

[0008] In one embodiment, the method for evaluating the health status of the battery pack further includes: obtaining the temperature of the battery pack after a preset time period of starting charging; if the temperature of the battery pack exceeds a preset temperature range, the health status of the range is not estimated during this charging process.

[0009] In one embodiment, the method for evaluating the health status of the battery pack further includes: obtaining a charging current of the battery pack within a preset voltage range; The battery pack's health assessment benchmark value within the preset voltage range is searched based on the charging current; if the health assessment benchmark value corresponding to the charging current cannot be found, the interval health status will not be estimated during this charging process.

[0010] In one embodiment, the method for evaluating the health status of a battery pack further includes: if a health assessment reference value corresponding to the charging current is found: calculating the actual charging capacity of the battery pack within a preset voltage range; and estimating the interval health status based on the actual charging capacity and the health assessment reference value.

[0011] The present application provides a method for evaluating the health status of a battery pack, wherein the battery pack includes: a shell; a plurality of battery cells accommodated in the shell; an electric tool interface arranged in the shell; and a first circuit board accommodated in the shell and electrically connected to the electric tool interface, wherein a first controller is arranged on the first circuit board; the evaluation method includes a method for calculating a health assessment reference value, the calculation method includes: calculating the actual charging capacity of the battery pack within a preset voltage range during the charging process of the battery pack; and calculating the health assessment reference value of the battery pack within the preset voltage range based on the actual charging capacity and the interval health status stored in the battery pack.

[0012] In one embodiment, the method for evaluating the health status of a battery pack further includes: obtaining the charging current of the battery pack within a preset voltage range; searching for a health assessment reference value of the battery pack within the preset voltage range based on the charging current; if the health assessment reference value corresponding to the charging current cannot be found, calling a calculation method to calculate the health assessment reference value corresponding to the charging current.

[0013] The present application also provides a charger and a battery pack for executing the above-mentioned health status assessment method.

[0014] The benefits of this application are that: the overall health status is evaluated by the interval health status of the battery pack, and it is not required to evaluate the health status of the battery pack during a complete charging and / or discharging cycle, so the evaluation conditions are easier to achieve; in addition, when the battery pack is connected to a new charging device, it can self-learn and store the corresponding health assessment benchmark value. The next time this charging device is used again, the health assessment benchmark value can be used to estimate the interval health status of the battery pack. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 A flowchart of a method for estimating the charge and discharge completion time of a battery pack provided in an embodiment of the present application; Figure 2 A schematic diagram of a voltage variation curve of a battery pack provided in an embodiment of the present application; Figure 3 A flowchart of another method for estimating the charge and discharge completion time of a battery pack provided in an embodiment of the present application; Figure 4 A structural block diagram of a device for calculating the charge and discharge completion time of a battery pack provided in an embodiment of the present application; Figure 5 A flowchart of another method for calculating the charge and discharge completion time of a battery pack provided in an embodiment of the present application; Figure 6 A schematic diagram of an impedance curve provided in an embodiment of the present application; Figure 7 A structural block diagram of another device for calculating the charge and discharge completion time of a battery pack provided in an embodiment of the present application; Figure 8A A structural block diagram of a power tool system provided in an embodiment of the present application; Figure 8B A structural block diagram of another electric tool system provided in an embodiment of the present application; Figure 8C A structural block diagram of another power tool system provided in an embodiment of the present application; Figure 9 A curve showing the relationship between the cut-off voltage and the temperature of a battery pack provided in an embodiment of the present application; Figure 10 A curve showing the relationship between the limiting current and the temperature of a battery pack provided in an embodiment of the present application; Figure 11 A flow chart of a method for determining discharge capacity parameters of a battery pack provided in an embodiment of the present application; Figure 12 A flowchart of another method for determining discharge capacity parameters of a battery pack provided in an embodiment of the present application; Figure 13 A flowchart of another method for determining discharge capacity parameters of a battery pack provided in an embodiment of the present application; Figure 14 A structural diagram of an electrical equipment system provided in an embodiment of the present application; Figure 15 for Figure 14 A schematic diagram of a partial structure of the electric tool; Figure 16 for Figure 14 The structural diagram of the battery pack in the figure; Figure 17 for Figure 14Exploded view of the battery pack in Figure 1; Figure 18 A structural diagram of another electrical equipment system provided in an embodiment of the present application; Figure 19 for Figure 18 The structural diagram of the charger in ; Figure 20 A flowchart of a method for evaluating the health status of a battery pack provided in an embodiment of the present application; Figure 21 A statistical graph showing the predicted and actual battery pack charging completion time provided in an embodiment of the present application; Figure 22 A statistical chart of the predicted and actual discharge completion time of a battery pack provided in an embodiment of the present application. DETAILED DESCRIPTION

[0016] Before any embodiments of the present application are explained in detail, it is to be understood that the application is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the foregoing drawings.

[0017] In this application, the terms "comprises," "includes," "has," or any other variations thereof are intended to encompass non-exclusive inclusion, such that a process, method, article, or apparatus that includes a list of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not preclude the presence of additional identical elements in the process, method, article, or apparatus that includes the element.

[0018] In this application, the term "and / or" describes a relationship between related objects, indicating that three possible relationships exist. For example, "A and / or B" can represent: A exists alone, A and B exist simultaneously, or B exists alone. Additionally, the character " / " in this application generally indicates that the related objects are in an "and / or" relationship.

[0019] In this application, the terms "connect," "combine," "couple," and "install" may refer to direct connection, combination, coupling, or installation, or indirect connection, combination, coupling, or installation. For example, a direct connection refers to two parts or components being connected together without the need for an intermediary, and an indirect connection refers to two parts or components being connected to at least one intermediary, with the two parts or components being connected via the intermediary. Furthermore, "connect" and "couple" are not limited to physical or mechanical connections or couplings and may include electrical connections or couplings.

[0020] In this application, it will be understood by those skilled in the art that relative terms (e.g., "about," "approximately," "substantially," etc.) used in conjunction with quantities or conditions include the values ​​and have the meaning indicated by the context. For example, the relative terms include at least the degree of error associated with the measurement of the specific value, the tolerance caused by manufacturing, assembly, and use associated with the specific value, etc. Such terms should also be considered to disclose a range defined by the absolute values ​​of the two endpoints. Relative terms may refer to plus or minus a certain percentage (e.g., 1%, 5%, 10% or more) of the indicated value. Numerical values ​​that do not use relative terms should also be disclosed as specific values ​​with tolerances. In addition, "substantially" when expressing a relative angular position relationship (e.g., substantially parallel, substantially perpendicular) may refer to plus or minus a certain degree (e.g., 1 degree, 5 degrees, 10 degrees or more) based on the indicated angle.

[0021] In this application, it will be understood by those skilled in the art that the function performed by an assembly can be performed by one assembly, multiple assemblies, one part, or multiple parts. Similarly, the function performed by a part can also be performed by one part, one assembly, or a combination of multiple parts.

[0022] In the present application, the terms "upper", "lower", "left", "right", "front", "back" and other directional words are described based on the orientation and positional relationship shown in the accompanying drawings, and should not be understood as limiting the embodiments of the present application. In addition, in the context, it is also necessary to understand that when it is mentioned that an element is connected to another element "upper" or "lower", it can not only be directly connected to the other element "upper" or "lower", but also be indirectly connected to the other element "upper" or "lower" through an intermediate element. It should also be understood that directional words such as upper side, lower side, left side, right side, front side, back side, etc. not only represent the positive orientation, but can also be understood as the lateral orientation. For example, below can include directly below, lower left, lower right, lower front and lower back, etc.

[0023] In this application, the terms "controller control module," "processor," "central processing unit," "CPU," and "MCU" are used interchangeably. Where a unit "controller," "processor," "central processing unit," "CPU," or "MCU" is used to perform a particular function, unless otherwise specified, those functions may be performed by a single unit or multiple units.

[0024] In this application, the terms "device", "module" or "unit" can be implemented in the form of hardware or software to achieve specific functions.

[0025] In this application, the terms "calculate", "judge", "control", "determine", "identify", etc. refer to the operations and processes of a computer system or similar electronic computing device (e.g., controller, processor, etc.).

[0026] In order to clearly illustrate the technical solution of the present application, the upper side, lower side, left side, right side, front side and rear side are defined in the drawings of the specification.

[0027] Figures 14 to 19 This is a structural diagram of the electric device system provided in this application. The electric device system includes a battery pack 1 and a host 2. The battery pack 1 is coupled to the host 2 and can transmit power to the host 2. In one embodiment, the electric device system can be a power tool system, in which the host 2 is a power tool 2, such as a chainsaw. The power tool 2 is powered by the battery pack 1. The battery pack 1 includes a housing 14, a plurality of battery cells 15 housed therein, a power tool interface 13 disposed on the housing 14, and a first circuit board 16 housed therein. A first controller 12 is disposed on the first circuit board 16 for power management of the battery pack 1. The battery pack 1 is coupled to the battery pack interface 23 of the power tool 2 via the power tool interface 13, achieving electrical and communication connection. The power tool 2 also includes a housing 24, with the battery pack interface 23 disposed therein. The housing 24 houses a second circuit board 26, on which a second controller 21 is disposed for controlling the power tool 2. In another embodiment, the electric device system can also be a charging system, in which the host 2 is a charger 2'. The charger 2' includes a housing 24' and a battery pack interface 23' provided on the housing 24'. A second circuit board 26' is housed in the housing 24', and a second controller 21' is provided on the second circuit board 26' for controlling the charger 2'. The electrical equipment system or the components in the system (such as the battery pack 1, the host 2) can execute the algorithm provided in this application to estimate and evaluate the state of health SOH, state of charge SOC, discharge capacity parameter SOP and charge and discharge completion time of the battery pack 1. The charger 2' shown in the figure has two battery pack interfaces 23', which can charge two battery packs at the same time and evaluate the relevant parameters of the two battery packs. Hosts with other numbers of battery pack interfaces can also use the algorithm provided in this application.

[0028] Figure 1 This is a flow chart of a method for estimating the charge and discharge completion time of a battery pack provided in an embodiment of the present application. This embodiment provides a method for estimating the charge and discharge completion time of a battery pack, which can be executed by a device for calculating the charge and discharge completion time of a battery pack, and the device can be implemented in the form of hardware and / or software. Figure 1 As shown, the method includes: S110 , calculating the discharge depth of the battery pack in real time based on data obtained by the voltage sensor and the current sensor.

[0029] The battery pack includes a detection component, which includes a voltage sensor and a current sensor. The voltage sensor is used to obtain real-time voltage data from the battery pack. This voltage data may include, but is not limited to, the voltage information of the battery pack in the static state and the voltage information of the battery pack during charging and discharging. The static voltage information of the battery pack is the open-circuit voltage of the battery pack. The open-circuit voltage of the battery pack at different depths of discharge can be measured in advance and stored in the battery pack. The current sensor is used to obtain real-time current data of the battery pack.

[0030] The charge and discharge completion time of a battery pack can be understood as the time required for the battery pack to reach the charge cutoff condition during charging, or the time required for the battery pack to reach the discharge cutoff condition during discharging. In one optional embodiment, the charge cutoff condition is the charge cutoff voltage. In one optional embodiment, the discharge cutoff condition is the discharge cutoff voltage. In one optional embodiment, the charge cutoff condition is the charge cutoff SoC. In one optional embodiment, the discharge cutoff condition is the discharge cutoff SoC.

[0031] The depth of discharge (DoD) of a battery pack refers to the percentage of the battery pack's discharged capacity relative to its rated capacity. When the battery pack is at rest, the DoD is a fixed value. In an optional embodiment, the DoD of the battery pack in its current state is determined based on voltage information acquired by a voltage sensor, namely, the battery pack's open-circuit voltage, and a table showing the relationship between open-circuit voltage and DoD. When the battery pack is charging or discharging, the voltage of the battery pack changes dynamically. In an optional embodiment, when the battery pack is charging, the DoD of the battery pack in its current state is determined based on the DoD of the battery pack at the previous moment and the charge added to the battery pack from the previous moment to the current moment. The charge added to the battery pack from the previous moment to the current moment is determined based on the current information during that time period. In an optional embodiment, when the battery pack is discharging, the DoD of the battery pack in its current state is determined based on the DoD of the battery pack at the previous moment and the charge lost from the battery pack from the previous moment to the current moment. The charge reduction of the battery pack during the time period from the previous moment to the current moment is obtained through the current information during the time period.

[0032] S120 : Determine a voltage variation curve of the battery pack based on the impedance curve and discharge depth of the battery pack.

[0033] The impedance curve of the battery pack can be a curve of the internal resistance of the battery pack at different depths of discharge, which is pre-measured, determined, and stored in the battery pack. In one embodiment, the impedance value of this impedance curve is the value of the normalized impedance that decouples temperature effects; this impedance curve, combined with the temperature prediction curve of the battery pack, can generate an impedance curve that includes temperature effects. Further, by combining the current under the current operating conditions and the open-circuit voltage of the battery pack at different depths of discharge, the voltage corresponding to the battery pack at different depths of discharge can be predicted, that is, the voltage variation curve.

[0034] Figure 2 This is a schematic diagram of a voltage change curve of a battery pack provided in an embodiment of the present application. In an optional embodiment, based on the impedance curve of the battery pack and the real-time calculation of the discharge depth of the battery pack, as well as the open circuit voltage of the battery pack at different discharge depths, the voltage of the battery pack corresponding to the discharge depth of each battery pack after the current moment is simulated and calculated to form the following: Figure 2 The voltage change curve of the battery pack is shown.

[0035] S130 : Determine the discharge depth at the end point of charge and discharge of the battery pack according to the voltage variation curve and the charge and discharge cut-off voltage of the battery pack.

[0036] The depth of discharge at the end point of a battery pack's charge or discharge refers to the depth of discharge when the battery pack reaches a charge cutoff condition during charging, or the depth of discharge when the battery pack reaches a discharge cutoff condition during discharge. In one embodiment, the charge cutoff condition is a charge cutoff voltage. In another embodiment, the discharge cutoff condition is a discharge cutoff voltage.

[0037] Specifically, after forming the voltage change curve, by comparing it with the charge and discharge cut-off voltage of the battery pack, the discharge depth corresponding to the charge and discharge cut-off voltage of the battery pack in the voltage change curve is used as the discharge depth at the charge and discharge end point of the battery pack.

[0038] S140: Calculate the charge and discharge completion time of the battery pack based on the discharge depth at the charge and discharge endpoint and the discharge depth at the current moment.

[0039] The charge and discharge completion time of a battery pack refers to the time required for the battery pack's discharge depth to reach the discharge depth at the end of the charge and discharge process from the current depth of discharge. Specifically, when the battery pack is charging, the charge completion time refers to the time required for the battery pack's discharge depth to reach the discharge depth at the end of the charge process. When the battery pack is discharging, the discharge completion time refers to the time required for the battery pack's discharge depth to reach the discharge depth at the end of the discharge process.

[0040] Specifically, the battery pack's depth of discharge is calculated in real time based on the data captured by the voltage and current sensors, namely, voltage and current data. The battery pack's voltage profile is then determined based on the battery pack's impedance curve and depth of discharge. The battery pack's depth of discharge at the end of charge and discharge is then determined based on the voltage profile and the battery pack's charge and discharge cutoff voltage stored in the battery pack. Finally, the battery pack's charge and discharge completion time is calculated based on the battery pack's end-of-charge depth of discharge and the current depth of discharge. This allows for real-time updates of the battery pack's charge and discharge completion time, improving the accuracy of the estimated charge and discharge completion time.

[0041] In this embodiment, the battery pack's depth of discharge is calculated in real time based on data acquired by the battery pack's voltage and current sensors. The battery pack's voltage profile is then determined based on the battery pack's impedance curve and depth of discharge. The battery pack's depth of discharge at the end of charge and discharge is then determined based on the voltage profile and the battery pack's charge and discharge cutoff voltage. Finally, the battery pack's charge and discharge completion time is calculated based on the battery pack's depth of discharge at the end of charge and discharge and the current depth of discharge. This allows the battery pack's charge and discharge completion time to be calculated based on the battery pack's real-time status, ensuring that the battery pack's charge and discharge completion time is unaffected by factors such as battery capacity, load size, charger characteristics, and operating environment. This improves the accuracy of the calculation of the estimated completion time for a battery pack undergoing charge and discharge, thereby enhancing the user experience.

[0042] Optional, Figure 3 This is a flow chart of another method for estimating the charge and discharge completion time of a battery pack provided in an embodiment of the present application. Based on the above embodiment, this embodiment further adds steps on how to calculate the discharge depth of the battery pack, how to determine the voltage change curve of the battery pack, how to determine the discharge depth at the end point of the charge and discharge of the battery pack, and how to calculate the charge and discharge completion time of the battery pack. Figure 3 As shown, the method specifically includes: S210 : Determine an initial depth of discharge based on voltage information of the battery pack obtained by a voltage sensor when the battery pack is at rest.

[0043] The battery pack being at rest can be understood as the battery pack not being charged or discharged. When the battery pack is at rest, the voltage information of the battery pack obtained by the voltage sensor is the open circuit voltage of the battery pack at the current moment.

[0044] In an optional embodiment, a voltage sensor obtains the open-circuit voltage of the battery pack at different depths of discharge and stores it in the battery pack. Before charging or discharging the battery pack, the voltage sensor obtains the battery pack voltage information and determines the current depth of discharge of the battery pack, i.e., the initial depth of discharge of the battery pack, based on the open-circuit voltage at different depths of discharge stored in the battery pack.

[0045] S220 : Calculate the current depth of discharge based on the initial depth of discharge, the maximum chemical capacity of the battery pack, and data acquired by the current sensor.

[0046] The maximum chemical capacity of the battery pack can be understood as the chemical capacity of the battery pack when fully charged. The data obtained by the current sensor can be current data. In an optional embodiment, the change in charge in the battery pack per unit time can be calculated based on the current data obtained by the current sensor. For example, when the battery pack is charging, the amount of charge added to the battery pack per unit time is calculated based on the current data obtained by the current sensor. When the battery pack is discharging, the amount of charge reduced from the battery pack per unit time is calculated based on the current data obtained by the current sensor. In an optional embodiment, the change in charge in the battery pack per unit time can be calculated using the ampere-hour integration method. In this way, the change in discharge depth can be calculated by the ratio of the amount of charge increased / decreased by the battery pack to the maximum chemical capacity of the battery pack. Combined with the initial discharge depth of the battery pack, the discharge depth of the battery pack in real time can be obtained, thereby improving the accuracy of the obtained discharge depth of the battery pack, which in turn helps to improve the accuracy of the calculation of the battery pack charge and discharge completion time.

[0047] In an optional embodiment, before determining the initial depth of discharge based on the voltage information of the battery pack obtained by the voltage sensor when the battery pack is at rest, the method further includes: determining the direction of the current in the battery pack based on the current data obtained in real time by the current sensor. When the direction of the current in the battery pack is positive, the battery pack is determined to be charging. Conversely, when the direction of the current in the battery pack is negative, the battery pack is determined to be discharging.

[0048] S230 , using the current depth of discharge as a starting point, simulate and calculate the voltage of the battery pack in a variable step size manner, and form a voltage change curve.

[0049] Specifically, the current depth of discharge is used as the starting point, and simulation is performed by stepping with variable step sizes, gradually superimposing different depths of discharge. The voltage of the battery pack at different depths of discharge under future loads is simulated and calculated to form a voltage change curve.

[0050] In an optional embodiment, to simplify the simulation calculation process, the future load of the battery pack can be assumed to remain unchanged, that is, the battery pack maintains its current load during charging or discharging. In some embodiments, the load of the battery pack can be understood as the current of the battery pack. In some embodiments, the load of the battery pack can be understood as the power of the battery pack.

[0051] S240. When the battery pack is charging, the discharge depth corresponding to the charge cut-off voltage in the voltage change curve is used as the discharge depth at the end point of charging of the battery pack; and the discharge depth corresponding to the discharge cut-off voltage in the voltage change curve is used as the discharge depth at the end point of discharging of the battery pack.

[0052] Among them, the charging cut-off voltage can be understood as the maximum voltage of the battery pack that is set. When the voltage of the battery pack reaches the charging cut-off voltage, the battery pack is controlled to stop charging to protect the battery pack. In an optional embodiment, the charging cut-off voltage is the charging cut-off condition set by the battery pack at the factory. In this case, the charging cut-off voltage can be the voltage when the battery pack is fully charged. In some embodiments, the charging cut-off voltage can be a charging cut-off condition developed by the user. In this case, the charging cut-off voltage is the voltage set by the user through a button or client according to needs. For example, when the user's demand is that the battery pack has as large a capacity as possible, the charging cut-off voltage can be set to the voltage when the battery pack is fully charged. On the contrary, when the user's demand is to extend the service life of the battery pack, the charging cut-off voltage can be set to be lower than the voltage corresponding to the battery pack when it is fully charged.

[0053] The discharge cut-off voltage can be understood as the minimum voltage of the battery pack. When the battery pack voltage reaches the discharge cut-off voltage, the battery pack is controlled to stop discharging to protect the battery pack. It is understood that, similar to the charge cut-off voltage, the discharge cut-off voltage can be the factory-set discharge cut-off condition of the battery pack, and can also be the charge cut-off condition developed by the user according to their needs. The similarities are not repeated here.

[0054] Specifically, after a voltage curve is generated through simulation calculation using the current depth of discharge as the starting point, if the battery pack is charging, the depth of discharge corresponding to the charge cutoff voltage in the voltage curve is used as the depth of discharge at the battery pack's charge endpoint. If the battery pack is discharging, the depth of discharge corresponding to the discharge cutoff voltage in the voltage curve is used as the depth of discharge at the battery pack's discharge endpoint. Because the voltage curve is generated through real-time simulation calculation, the depth of discharge corresponding to the charge and discharge cutoff voltage in the discharge curve changes in real time with the current state of the battery pack, making the determined depth of discharge at the battery pack's charge and discharge endpoint more accurate, thereby improving the accuracy of the calculation of the battery pack's charge and discharge completion time.

[0055] S250: Calculate the charge and discharge completion time of the battery pack according to the first calculation formula.

[0056] The first calculation formula is as follows: T=|DOD final -DOD now |*Q max / I now Wherein, T is the time for charge and discharge to be completed. final DOD is the depth of discharge at the end of charge and discharge. now is the discharge depth at the current moment. max is the maximum chemical capacity of the battery pack. now is the current of the battery pack at the current moment.

[0057] Specifically, the charge and discharge status of the battery pack is determined based on current data acquired by the battery pack's current sensor. When it is determined that the battery pack is charging, the current depth of discharge is calculated based on the initial depth of discharge, the maximum chemical capacity of the battery pack, and the data acquired by the current sensor. The battery pack voltage is then simulated and calculated using the current depth of discharge as a starting point, with a variable step size, to form a voltage curve. The depth of discharge corresponding to the charge cutoff voltage in the voltage curve is then used as the depth of discharge at the end of charging for the battery pack. Finally, the charge completion time of the battery pack is calculated according to the first calculation formula. Accordingly, when it is determined that the battery pack is discharging, the current depth of discharge is calculated based on the initial depth of discharge, the maximum chemical capacity of the battery pack, and the data acquired by the current sensor. The battery pack voltage is then simulated and calculated using the current depth of discharge as a starting point, with a variable step size, to form a voltage curve. The depth of discharge corresponding to the discharge cutoff voltage in the voltage curve is then used as the depth of discharge at the end of discharging for the battery pack. Finally, the discharge completion time of the battery pack is calculated according to the first calculation formula. In this way, by calculating the status of the battery pack in real time and estimating the charge and discharge completion time of the battery pack, the charge and discharge completion time of the battery pack is made more accurate, which is beneficial for users to reasonably arrange the use time of power tools according to the charge and discharge completion time of the battery pack.

[0058] In this embodiment, the battery pack voltage is simulated and calculated using a variable step size, starting with the current depth of discharge (DOD) and generating a voltage curve. This curve is updated in real time based on the battery pack's status, making the DOD at the end of charge and discharge determined based on the voltage curve more accurate, thereby improving the accuracy of the battery pack's charge and discharge completion time. Furthermore, using the first calculation formula to calculate the battery pack's charge and discharge completion time simplifies the calculation process, thereby conserving computing resources.

[0059] Based on the same concept, this application also provides a device for calculating the charge and discharge completion time of a battery pack. This device can be implemented in hardware and / or software. The battery pack includes a detection component, which includes a voltage sensor and a current sensor. Figure 4 This is a structural block diagram of a device for calculating the charge and discharge completion time of a battery pack provided in an embodiment of the present application, with reference to Figure 4 As shown, the device for calculating the charge and discharge completion time of the battery pack includes: The discharge depth determination module 410 is used to calculate the discharge depth of the battery pack in real time based on data obtained by the voltage sensor and the current sensor.

[0060] A voltage change curve determination module 420 is configured to determine a voltage change curve of the battery pack based on the impedance curve and discharge depth of the battery pack; The charge and discharge endpoint determination module 430 is configured to determine the discharge depth at the charge and discharge endpoint of the battery pack based on the voltage variation curve and the charge and discharge cut-off voltage of the battery pack.

[0061] The charge and discharge completion time determination module 440 is configured to determine the charge and discharge completion time of the battery pack based on the discharge depth at the charge and discharge endpoint and the discharge depth at the current moment.

[0062] The device for calculating the charge and discharge completion time of a battery pack provided in an embodiment of the present application can execute the method for calculating the charge and discharge completion time of a battery pack provided in any embodiment of the present application, and has functional modules and beneficial effects corresponding to the execution method. The similarities can be referred to the above description.

[0063] Figure 5 This is a flow chart of another method for calculating the charge and discharge completion time of a battery pack provided in an embodiment of the present application. Based on the above embodiment, this embodiment further adds the steps of updating the impedance curve of the battery pack and updating the maximum chemical capacity of the battery pack. Figure 5 As shown, the method specifically includes: S310 , calculating the depth of discharge of the battery pack in real time based on data obtained by the voltage sensor and the current sensor.

[0064] S320: Calculate the impedance information of the battery pack in real time based on the data obtained by the voltage sensor and the current sensor.

[0065] The impedance information of the battery pack can be understood as the impedance of the battery pack at the current moment. Specifically, the impedance of the battery pack is calculated based on the voltage data obtained by the voltage sensor and the current data obtained by the current sensor.

[0066] In an optional embodiment, the impedance information of the battery pack is calculated in real time based on the data obtained by the voltage sensor and the current sensor, including: after a preset time after the start of charging / discharging, the impedance information at the current moment is calculated in real time based on the terminal voltage and open-circuit voltage of the battery pack obtained by the voltage sensor, and the current of the battery pack obtained by the current sensor.

[0067] The preset time can be determined based on the characteristics of the battery. In an optional embodiment, the preset time can be the time from the start of charging / discharging to the stabilization of the terminal voltage of the battery pack. In an exemplary embodiment, the preset time is 200 seconds.

[0068] In this embodiment, the impedance information at the current moment is calculated in real time based on the terminal voltage and open circuit voltage of the battery pack and the current of the battery pack after a preset time from the start of charging / discharging, so that the obtained impedance information is more accurate.

[0069] S330 : Determine temperature information of the battery pack based on data acquired by the temperature sensor.

[0070] The detection component also includes a temperature sensor. The temperature sensor is used to obtain real-time temperature information of the battery pack. The temperature information may include the current temperature and a predicted temperature curve. In one embodiment, based on the data obtained by the temperature sensor, the heat generation and temperature change rate of the battery pack are calculated to determine the predicted temperature curve of the battery pack.

[0071] S340: Update the impedance curve of the battery pack based on the impedance information and temperature information obtained in real time.

[0072] Figure 6 A schematic diagram of an impedance curve provided in an embodiment of the present application. Specifically, after obtaining the impedance information and temperature information of the battery pack, the normalized impedance is calculated based on the impedance information and temperature information obtained in real time, and then the impedance curve of the battery pack is updated according to the normalized impedance. In an exemplary embodiment, the updated impedance curve is as follows: Figure 6As shown. In an optional embodiment, based on the impedance information and temperature information obtained in real time, calculating the normalized impedance may include converting the real-time acquired impedance information into the impedance corresponding to 0°C according to the temperature information. The purpose of calculating the normalized impedance is to decouple the influence of temperature on the impedance. By comparing the difference between the normalized impedance obtained in this calculation and the impedance of the battery pack's impedance curve corresponding to the current discharge depth, the change ratio of the battery pack's impedance under the current working condition can be obtained, and the impedance curve of the battery pack can be updated according to the change ratio. Due to the existence of situations such as detecting abnormal points, it is understandable that certain preset conditions need to be met before updating the impedance curve of the battery pack. In an optional embodiment, if the normalized impedance does not meet the preset condition, the impedance corresponding to the discharge depth in the impedance curve of the battery pack is used as the impedance of the discharge depth in the updated impedance curve. The preset condition can be that the difference between the normalized impedance and the impedance corresponding to the discharge depth in the impedance curve of the battery pack is within a first preset range. The first preset range can be set according to actual conditions.

[0073] In an optional embodiment, updating the impedance curve of the battery pack based on the real-time acquired impedance information and temperature information includes performing linear regression on the real-time acquired impedance information to obtain a corrected impedance. Then, updating the impedance curve of the battery pack based on the corrected impedance and temperature information.

[0074] In an optional embodiment, to reduce the amount of calculation, performing linear regression on the impedance information acquired in real time can be understood as performing linear regression on the most recent finite set of impedance information acquired in real time, for example, performing linear regression on the four most recently acquired sets of impedance information to obtain the corrected impedance.

[0075] Specifically, after obtaining the impedance information and temperature information of the battery pack, linear regression is performed on the impedance information obtained in real time to obtain the corrected impedance, and then the normalized impedance is calculated based on the corrected impedance and temperature information, so as to update the impedance curve of the battery pack according to the difference between the normalized impedance and the impedance corresponding to the current discharge depth in the impedance curve.

[0076] S350: Determine a voltage variation curve of the battery pack based on the impedance curve and discharge depth of the battery pack.

[0077] S360: Determine the discharge depth at the end point of charge and discharge of the battery pack according to the voltage variation curve and the charge and discharge cut-off voltage of the battery pack.

[0078] S370: Update the maximum chemical capacity Q of the battery pack based on the current data and discharge depth. max .

[0079] Specifically, the charge change per unit time can be determined based on the current data obtained by the current sensor, thereby calculating and updating the maximum chemical capacity of the battery pack based on the charge change per unit time and the depth of discharge of the battery pack obtained in real time. In some embodiments, when the calculated maximum chemical capacity of the battery pack meets the rapid update condition, the calculated maximum chemical capacity of the battery pack is stored as the maximum chemical capacity of the battery pack. In some embodiments, when the calculated maximum chemical capacity of the battery pack does not meet the rapid update condition, the maximum chemical capacity of the battery pack is not updated. The rapid update condition includes that the difference between the calculated maximum chemical capacity of the battery pack and the maximum chemical capacity stored in the battery pack is within a second preset range. The second preset range can be set according to actual conditions.

[0080] S380: Calculate the charge and discharge completion time of the battery pack according to the first calculation formula.

[0081] The first calculation formula is as follows: T=|DOD final -DOD now |*Q max / I now Wherein, T is the time for charge and discharge to be completed. final DOD is the depth of discharge at the end of charge and discharge, that is, the end-point discharge depth. now is the current depth of discharge. max is the maximum chemical capacity of the battery pack. now is the current of the battery pack at the current moment.

[0082] In an optional embodiment, after calculating the charge and discharge completion time of the battery pack, the method further includes smoothing the charge and discharge completion time.

[0083] The smoothing of the charge and discharge completion time may include, but is not limited to, eliminating excessively large or small charge and discharge completion times and normalizing the obtained charge and discharge completion times to reduce the difference between the charge and discharge completion times calculated at each moment.

[0084] In this embodiment, the battery pack's impedance information is calculated in real time based on data acquired by the voltage and current sensors, and the battery pack's temperature information is determined based on temperature information acquired by the temperature sensor. This updates the battery pack's impedance curve based on the real-time impedance and temperature information, making the determined battery pack's voltage curve more accurate. Furthermore, the maximum chemical capacity of the battery pack is updated based on current data and depth of discharge acquired by the current sensor, further improving the accuracy of the battery pack's charge and discharge completion time.

[0085] Optional, Figure 7 This is a structural block diagram of another device for calculating the charge and discharge completion time of a battery pack provided in an embodiment of the present application, with reference to Figure 7 As shown, the device for calculating the charge and discharge completion time of the battery pack includes: The discharge depth determination module 410 is used to calculate the discharge depth of the battery pack in real time based on data obtained by the voltage sensor and the current sensor.

[0086] The impedance curve update module 411 is used to calculate the impedance information of the battery pack in real time based on the data obtained by the voltage sensor and the current sensor; determine the temperature information of the battery pack based on the temperature information obtained by the temperature sensor; and update the impedance curve of the battery pack based on the impedance information and temperature information obtained in real time.

[0087] The voltage variation curve determination module 420 is configured to determine the voltage variation curve of the battery pack based on the impedance curve and the depth of discharge of the battery pack.

[0088] The charge and discharge endpoint determination module 430 is configured to determine the discharge depth at the charge and discharge endpoint of the battery pack based on the voltage variation curve and the charge and discharge cut-off voltage of the battery pack.

[0089] The maximum chemical capacity update module 431 is used to update the maximum chemical capacity Q of the battery pack according to the current data and discharge depth obtained by the current sensor. max .

[0090] The charge and discharge completion time determination module 440 is configured to calculate the charge and discharge completion time of the battery pack according to a first calculation formula.

[0091] The device for calculating the charge and discharge completion time of a battery pack provided in an embodiment of the present application can execute the method for calculating the charge and discharge completion time of a battery pack provided in the above embodiment, and has functional modules and beneficial effects corresponding to the execution method. The similarities can be referred to the above description.

[0092] In one embodiment, Figure 4 and Figure 7 The computing device shown is arranged in the battery pack 1, for example, the first controller 12. The first controller 12 is communicated with the detection component 11 in the battery pack, for example, it is communicated with the voltage sensor and the current sensor in the battery pack to obtain voltage and current data; other information, such as the relationship table between open circuit voltage and discharge depth, and the charge and discharge cut-off voltage, can also be pre-stored in the memory of the battery pack 1.

[0093] In another embodiment, Figure 4 and Figure 7The computing device shown is located in a host computer 2 coupled to a battery pack 1, such as a second controller 21. The host computer 2 can be a device that uses the battery pack 1 to discharge electricity, such as a power tool, lamp, or energy station, or a device that charges the battery pack 1, such as a charger or adapter. The host computer 2 includes a housing 24 and a battery pack interface 23 disposed therein for coupling with the battery pack 1. Optionally, the host computer itself includes a detection component 11, which is communicatively connected to the second controller 21 of the host computer 2. The detection component 11 can include a current sensor to detect the current flowing into or out of the battery pack. Specifically, a charger includes a current sensor to detect the charging current supplied to the battery pack, while a power tool includes a current sensor to detect the discharge current discharged from the battery pack. Optionally, the second controller 21 of the host computer 2 can also communicate with the detection component 11 within the battery pack 1. The battery pack 1 transmits data detected by the detection component 11 within the battery pack to the host computer 2 via the power tool interface 13 and the battery pack interface 23. For example, voltage data detected by a voltage sensor and temperature data detected by a temperature sensor are transmitted to the second controller 21 of the host computer 2. Other information, such as a relationship table between open circuit voltage and discharge depth, and a charge and discharge cut-off voltage, may also be pre-stored in the memory of the host 21 .

[0094] In some embodiments, host 2 can store information related to different types of battery packs or cells and match them when a battery pack is inserted, thereby calculating the charge and discharge completion time of different types of battery packs. In other words, an electrical device system consisting of battery pack 1 and host 2, such as a power tool system consisting of a battery pack and a power tool, or a charging system consisting of a battery pack and a charger, can also use the battery pack charge and discharge completion time calculation method provided in the above embodiments to calculate the battery pack charge and discharge completion time.

[0095] Figure 21 A graph showing the estimated battery pack charging completion time and the actual battery pack charging completion time when a computing device implements the method for calculating the battery pack charging and discharging completion time provided by the above embodiment is shown; Figure 22 The diagram shows the result of a calculation method for the charge and discharge completion time of a battery pack provided by the above embodiment implemented by a computing device, and the estimated discharge completion time of the battery pack and the actual discharge completion time of the battery pack.

[0096] Figures 8A to 8C The present invention provides an electric equipment system, specifically a structural block diagram of an electric tool system, with reference to Figure 8A and Figure 8B As shown, the power tool system includes a battery pack 1 and a power tool 2 that are electrically connected. Figure 8C As shown, the power tool system may further include a power tool 2 and a battery module 25 built into the power tool 2 .

[0097] like Figure 8A As shown, the battery pack 1 includes a detection component 11, a power tool interface 13, and a first controller 12. The detection component 11 is used to detect the status parameters of the battery pack 1. The detection component 11 and the power tool interface 13 are both connected to the first controller 12. The first controller 12 is configured to determine the discharge capacity parameters of the battery pack based on the status parameters and transmit the discharge capacity parameters to the power tool interface 13.

[0098] The power tool 2 includes a battery pack interface 23 and a second controller 21. The battery pack interface 23 is coupled to the power tool interface 13. The battery pack interface 23 is configured to receive the discharge capacity parameter transmitted by the power tool interface 13. The second controller 21 is connected to the battery pack interface 23. The second controller 21 is configured to control the operating state of the power tool system based on the discharge capacity parameter.

[0099] Based on the same concept, the present application also provides a battery pack 1, including a shell 14, a detection component 11, a first controller 12 and a power tool interface 13. The detection component 11 is arranged in the shell 14. The detection component 11 is used to detect the status parameters of the battery pack 1. The first controller 12 is communicatively connected to the detection component 11. The first controller 12 is configured to: determine the discharge capacity parameters of the battery pack 1 according to the status parameters. The power tool interface 13 is electrically connected to the first controller 12. The power tool interface 13 is used to couple with the power tool 2 to send the discharge capacity parameters to the power tool 2.

[0100] The battery pack 1 can be electrically connected to the power tool 2 , so that the battery pack 1 supplies power to the power tool 2 .

[0101] Based on the same concept, the present application also provides an electric tool 2, comprising an energy storage device, a detection component 11, and a second controller 21. The detection component 11 is used to detect the state parameters of the energy storage device. The second controller 21 is in communication with the detection component 11. The second controller 21 is configured to determine the discharge capacity parameters of the energy storage device according to the state parameters, and control the working state of the electric tool 2 according to the discharge capacity parameters. Figure 8A As shown, in an optional embodiment, the energy storage device includes a detachable battery pack 1, and the detection component 11 is arranged in the battery pack housing 14. The status parameters obtained by the detection component 11 are sent by the first controller 12 to the second controller 21 through the battery pack interface 23 and the power tool interface 13. The second controller 21 is configured to determine the discharge capacity parameters of the energy storage device according to the status parameters, and control the working state of the power tool 2 according to the discharge capacity parameters.

[0102] like Figure 8BAs shown, in an optional embodiment, the energy storage device includes a detachable battery pack 1, and the detection component 11 is partially arranged in the shell 14 of the battery pack 1 and partially arranged in the casing 24 of the power tool 2. The state parameters obtained by the detection component 11 arranged in the shell 14 of the battery pack 1 are sent by the first controller 12 to the second controller 21 through the battery pack interface 23 and the power tool interface 13; the state parameters obtained by the detection component 11 arranged in the casing 24 of the power tool 2 are directly sent to the second controller 21. The second controller 21 is configured to determine the discharge capacity parameters of the energy storage device according to the state parameters, and control the working state of the power tool 2 according to the discharge capacity parameters.

[0103] like Figure 8C As shown, in other embodiments, the energy storage device may further include a battery module 25, which is built into the housing 24 of the power tool. The first controller 12' and the second controller 21 are also both arranged in the housing 24 of the power tool 2 and can communicate with each other. In this embodiment, the first controller 12' can be understood as the power management board of the power tool 2, and the second controller 21 can be understood as the power control board of the power tool 2. The first controller 12' and the second controller 21 can also be a single controller integrating the above functions. The detection component 11 is also arranged in the housing 24 of the power tool 2, and is used to detect the status parameters of the battery module 25 and send them to the first controller 12' or the second controller 21. The first controller 12' or the second controller 21 is configured to determine the discharge capacity parameters of the energy storage device based on the status parameters, and the second controller 21 controls the working state of the power tool 2 based on the discharge capacity parameters calculated by itself or obtained from the first controller 12'.

[0104] In summary, the detection component 11 can be entirely disposed in the battery pack 1, partially disposed in the battery pack 1 and partially disposed in the power tool 2, or entirely disposed in the power tool 2. Specifically, the state parameters include the voltage, current, and temperature of the battery (i.e., the battery pack 1 or the battery cell module 25). The detection component 11 includes a voltage sensor, a current sensor, and a temperature sensor. Optionally, the voltage sensor and the temperature sensor are disposed in the battery pack 1, and the current sensor is disposed in the power tool 2. The discharge capacity parameters of the energy storage device are determined based on the state parameters obtained by the detection component 11, which can be implemented by the first controller 12 or by the second controller 21. The first controller 12 can transmit the calculated discharge capacity parameters to the second controller 12, or it can transmit the original or filtered voltage, current, and temperature data to the second controller 21.

[0105] The discharge capability parameter includes at least one of a first discharge capability parameter and a second discharge capability parameter. The first discharge capability parameter includes the discharge capability of the battery pack 1 when the battery pack 1 is controlled to discharge instantaneously until the voltage of the battery pack 1 meets a cutoff condition. The second discharge capability parameter includes the discharge capability of the battery pack 1 when the battery pack 1 is controlled to discharge continuously until the voltage of the battery pack 1 meets the cutoff condition.

[0106] In other embodiments, when the energy storage device includes a battery cell module 25, the discharge capacity parameter includes at least one of a first discharge capacity parameter and a second discharge capacity parameter. The first discharge capacity parameter includes controlling the battery cell module 25 to discharge instantaneously until the voltage of the battery cell module 25 meets the cut-off condition, and the discharge capacity of the battery cell module 25. The second discharge capacity parameter includes controlling the battery cell module 25 to discharge continuously until the voltage of the battery cell module 25 meets the cut-off condition, and the discharge capacity of the battery cell module 25. It should be noted that since the first controller of the battery cell module 25 has the same function as the first controller of the battery pack, unless otherwise specified, the following description will take the energy storage module including the battery pack as an example.

[0107] It should be noted that the discharge capability parameter including at least one of the first discharge capability parameter and the second discharge capability parameter can be understood as the discharge capability parameter including the first discharge capability parameter, or the discharge capability parameter including the second discharge capability parameter, or the discharge capability parameter including the first discharge capability parameter and the second discharge capability parameter.

[0108] The cut-off condition can be understood as the condition for the battery pack 1 to stop discharging. In some embodiments, the discharge cut-off condition can be that the depth of discharge of the battery pack 1 is less than or equal to the minimum depth of discharge allowed by the battery pack 1. In some embodiments, the discharge cut-off condition can be that the voltage of the battery pack 1 is less than or equal to the minimum voltage allowed by the battery pack 1. Controlling the battery pack 1 to discharge instantaneously until the voltage of the battery pack 1 satisfies the cut-off condition can be understood as obtaining, through state estimation, that the battery pack 1 discharges instantaneously from the current state to the state of the battery pack 1 satisfies the cut-off condition. For example, the battery pack 1 discharges from the current state to the state of the battery pack 1 within 1s to the state of the battery pack 1 satisfies the cut-off condition. Controlling the battery pack 1 to discharge continuously until the voltage of the battery pack 1 satisfies the cut-off condition can be understood as obtaining, through state estimation, that the battery pack 1 discharges continuously from the current state to the state of the battery pack 1 to the state of the battery pack 1 satisfies the cut-off condition. For example, the battery pack 1 discharges from the current state to the state of the battery pack 1 within 10s to the state of the battery pack 1 satisfies the cut-off condition.

[0109] In an optional embodiment, the discharge capacity parameter of the battery pack 1 includes a current limit value or a power limit value, that is, the maximum current or maximum power that the battery pack 1 can output, thereby making the control basis on the power tool 2 side simpler.

[0110] At least a portion of the detection assembly 11, the first controller 12, and the power tool interface 13 are disposed within the housing 14 of the battery pack 1. The housing 14 protects the components disposed therein. The detection assembly 11 may include, but is not limited to, a current sensor, a voltage sensor, and a temperature sensor, thereby enabling detection of battery pack status parameters. In an optional embodiment, the battery pack status parameters may include, but are not limited to, at least one of current information, voltage information, and temperature information of the battery pack 1.

[0111] The power tool interface 13 is electrically connected to the first controller 12 and is also coupled to the power tool 2. Specifically, the power tool interface 13 is electrically connected to the battery pack interface 23 of the power tool 2. The power tool interface 13 is used to transmit the discharge capacity parameters of the battery pack 1 to the battery pack interface 23 of the power tool 2. The battery pack interface 23 of the power tool 2 is connected to the second controller 21, so that the second controller 21 can control the operating state of the power tool based on the discharge capacity parameters received by the battery pack interface 23.

[0112] The power tool 2 includes a motor 22, and controlling the working state of the power tool 2 may include, but is not limited to, controlling the current of the motor 22 in the power tool 2 to be less than a current limit value, or controlling the power of the motor 22 in the power tool 2 to be less than a power limit value.

[0113] In this embodiment, the first controller is configured to determine the discharge capacity parameters of the battery pack based on the state parameters of the battery pack, wherein the discharge capacity parameters include at least one of the first discharge capacity parameter and the second discharge capacity parameter. Thus, the discharge capacity of the battery pack is determined based on the state parameters of the battery pack. This prevents excessive power usage of the battery pack while fully utilizing the power of the battery pack to fully utilize the capacity of the battery pack, thereby improving the service life and safety performance of the battery pack.

[0114] In an optional embodiment, when the state parameters include current information, voltage information and temperature information, the first controller 12 is specifically configured to: calculate the state of charge of the battery pack 1 based on the current information and voltage information; determine the instantaneous DC resistance and / or continuous DC resistance of the battery pack 1 based on the state of charge and temperature information; determine the first discharge capacity parameter based on the cutoff condition and the instantaneous DC resistance of the battery pack 1, and / or determine the second discharge capacity parameter based on the cutoff condition and the continuous DC resistance.

[0115] The current information may include the current of the battery pack 1 acquired in real time by the detection component 11. The voltage information may include the open circuit voltage of the battery pack 1 acquired by the detection component 11 before discharge, thereby calculating the state of charge of the battery pack 1 through the ampere-hour integration method.

[0116] The instantaneous DC resistance of the battery pack 1 can be understood as the DC resistance of the battery pack 1 when the battery pack 1 is instantaneously discharged from its current state until the battery pack state meets the cut-off condition. The continuous DC resistance of the battery pack 1 can be understood as the DC resistance of the battery pack 1 when the battery pack 1 is continuously discharged from its current state until the battery pack state meets the cut-off condition.

[0117] In an optional embodiment, determining the instantaneous DC resistance and / or continuous DC resistance of the battery pack 1 based on the state of charge and temperature information may include obtaining the instantaneous DC resistance and / or continuous DC resistance of the battery pack 1 by a table lookup method based on the temperature information and the state of charge.

[0118] In some embodiments, the first discharge capability and the second discharge capability include a current limit value. The first discharge capability parameter is determined according to the cutoff condition and the instantaneous DC resistance of the battery pack 1, including: determining the instantaneous voltage before discharge of the battery pack 1 according to the current information, and determining the instantaneous discharge current limit value of the battery pack 1 according to the instantaneous voltage before discharge, the cutoff condition and the instantaneous DC resistance of the battery pack.

[0119] The instantaneous voltage before discharge of the battery pack 1 can be understood as the voltage of the battery pack at the moment before discharge, for example, the voltage within 1 second before discharge.

[0120] In some embodiments, the first discharge capability and the second discharge capability include a current limit value, and the second discharge capability parameter is determined based on the cutoff condition and the continuous DC resistance, including: determining the continuous voltage before discharge of the battery pack 1 based on the current information, and determining the continuous discharge current limit value of the battery pack 1 based on the continuous voltage before discharge, the cutoff condition and the continuous DC resistance.

[0121] The continuous voltage of the battery pack 1 before discharge can be understood as the voltage maintained by the battery pack 1 before discharge, for example, the average voltage of the battery pack 1 within 10 seconds before discharge.

[0122] In some embodiments, the cut-off condition includes a cut-off voltage, which is determined according to the minimum temperature of the battery pack 1 .

[0123] The cutoff voltage can be understood as the minimum voltage allowed by the battery pack 1, that is, the lowest voltage that the battery pack 1 can normally output. The minimum temperature of the battery pack 1 can be understood as the lowest temperature measured at each measurement point in the battery pack 1. It should be noted that the cutoff voltage value can be set differently depending on the temperature of the battery pack 1. The curve of the cutoff voltage of the battery pack 1 and the temperature of the battery pack 1 can include one or more segments.

[0124] In an exemplary embodiment, Figure 9As shown, when the temperature of the battery pack 1 is greater than 0°C, the cut-off voltage Vmin of the battery pack 1 can be set to 2.5V. When the temperature of the battery pack 1 is less than -20°C, the cut-off voltage Vmin of the battery pack 1 can be set to 2V. When the temperature of the battery pack 1 is greater than -20°C and less than 0°C, the cut-off voltage Vmin of the battery pack 1 smoothly transitions from 2V to 2.5V as the temperature rises. It should be noted that Figure 9 This example illustrates only that when the temperature of the battery pack 1 is greater than -20°C and less than 0°C, the cutoff voltage of the battery pack 1 transitions linearly and smoothly from 2V to 2.5V as the temperature increases. In other embodiments, the cutoff voltage of the battery pack 1 may transition nonlinearly and smoothly from 2V to 2.5V as the temperature increases. This embodiment does not specifically limit the type of smooth transition of the cutoff voltage of the battery pack 1.

[0125] In some embodiments, if the instantaneous voltage before discharge or the continuous voltage before discharge is lower than the cut-off voltage, the battery pack is controlled to stop discharging, that is, the power tool 2 is controlled to shut down to protect the power tool 2 and extend the service life of the power tool 2.

[0126] In some embodiments, controlling the power tool 2 to shut down includes controlling the power tool 2 to shut down after a preset time based on current information, which is beneficial for improving the user experience of the power tool 2 .

[0127] The preset time can be set based on current information. If the current value of battery pack 1 is greater than I1, the preset time can be set to t1. If the current value of battery pack 1 is less than I2, the preset time can be set to t3. If the current value of battery pack 1 is less than I1 and greater than I2, the preset time can be set to t2. Here, I1>I2, t1<t2<t3.

[0128] In some embodiments, if the pre-discharge instantaneous voltage or the pre-discharge sustained voltage is not lower than the cut-off voltage, current limiting protection is performed on the power tool system based on the temperature parameter. It is understood that current limiting of the power tool system can be understood as current limiting protection of the battery pack or current limiting protection of the power tool.

[0129] The current limiting protection of the power tool system according to the temperature parameters can be understood as determining the cut-off voltage of the battery pack 1 according to the temperature parameters, thereby determining the discharge capacity parameters of the battery pack 1, and then controlling the working state of the power tool 2 according to the discharge capacity parameters of the battery pack 1.

[0130] In some embodiments, the battery pack 1 also performs under-temperature or over-temperature protection based on temperature information, that is, when the temperature of the battery pack 1 is within a preset temperature range, the working state of the power tool 2 is controlled according to the current limit value, and when the temperature of the battery pack 1 is not within the preset temperature range, the current value output by the battery pack 1 to the power tool 2 is further limited, so as to maximize the capacity of the battery pack 1 while protecting the battery pack 1.

[0131] The preset temperature range is set according to the temperature range in which the battery pack 1 can operate normally. In an exemplary embodiment, the preset temperature range is [-20° C., 70° C.].

[0132] In an exemplary embodiment, Figure 10 As shown, when the temperature of the battery pack is less than zero T1 or greater than T4, the current value of the battery pack is limited to 0 mA, that is, the battery pack 1 is prohibited from discharging. When the temperature of the battery pack 1 is between [T2, T3], that is, the temperature of the battery pack 1 is within the preset temperature range, the current value of the battery pack 1 is controlled according to the determined discharge capacity parameter of the battery pack 1. When the temperature of the battery pack 1 is between [T1, T2] or [T3, T4], the current value of the battery pack 1 is limited to smoothly transition between 0 and the determined current limit value. In an exemplary embodiment, a smooth transition is adopted between -30°C and -20°C and between 70°C and 80°C, such as multiplying by a proportional coefficient that changes with temperature.

[0133] Figure 11 This is a flow chart of a method for determining the discharge capacity parameters of a battery pack provided in an embodiment of the present application. Figure 11 As shown, this embodiment also provides a method for determining the discharge capacity parameters of a battery pack, which is as follows: S510: Obtain status parameters of the battery pack.

[0134] The state parameter of the battery pack includes at least one of current information, voltage information and temperature information of the battery pack.

[0135] S520: Calculate the state of charge of the battery pack based on the current information and the voltage information.

[0136] S530 : Determine the instantaneous DC resistance and / or continuous DC resistance of the battery pack according to the state of charge and temperature information of the battery pack.

[0137] S540: Determine the instantaneous voltage before discharge and the continuous voltage before discharge of the battery pack according to the current information.

[0138] S550: Determine whether the instantaneous voltage before discharge or the continuous voltage before discharge is lower than the cut-off voltage; if so, execute S560; if not, execute S570.

[0139] S560: Control the battery pack to stop discharging after a preset time according to the current information.

[0140] S570. Determine a first discharge capability parameter based on the instantaneous voltage before discharge, the cutoff condition, and the instantaneous DC resistance of the battery pack; and / or determine a second discharge capability parameter based on the continuous voltage before discharge, the cutoff condition, and the continuous DC resistance.

[0141] The discharge capability parameter includes at least one of a first discharge capability parameter and a second discharge capability parameter. The first discharge capability parameter includes the discharge capability of the battery pack when controlling instantaneous discharge of the battery pack until the battery pack state meets a cutoff condition. The second discharge capability parameter includes the discharge capability of the battery pack when controlling continuous discharge of the battery pack until the battery pack state meets the cutoff condition. The first discharge capability parameter and the second discharge capability parameter include current limit values ​​or power limit values.

[0142] S580: Perform current limiting protection on the battery pack according to the temperature parameter and the discharge capacity parameter.

[0143] Figure 12 This is a flow chart of another method for determining the discharge capacity parameters of a battery pack provided in an embodiment of the present application. Figure 12 As shown, this embodiment also provides another method for determining the discharge capability parameters of a battery pack, which can be used to determine the first discharge capability parameter and / or the second discharge capability parameter, that is, the values ​​of the instantaneous and / or continuous discharge capability parameters. For example, the current limit value that meets the target continuous discharge time (the target continuous discharge time is set to be short and less than or equal to the first time threshold, such as 1s or 3s, which is the first discharge capability parameter; the target continuous discharge time is set to be long and greater than the first time threshold, such as 10s or 30s, which is the second discharge capability parameter). The details are as follows: S610: Obtain status parameters of the battery pack.

[0144] The battery pack status parameters include at least one of the battery pack's current information, voltage information, and temperature information. The battery pack status parameters can be obtained from a detection component. As previously described, the detection component can be partially or fully incorporated into the battery pack or the power tool, and will not be further described here.

[0145] S620: Determine a first reference value of a discharge capability parameter based on the voltage constraint.

[0146] The first reference value is determined according to the open circuit voltage and resistance of the battery pack in accordance with Ohm's law. Specifically, the current discharge depth of the battery pack is first calculated based on the current and voltage. According to the current discharge depth, the corresponding current open circuit voltage and instantaneous DC resistance are obtained by, for example, looking up a table. The instantaneous maximum discharge current can be calculated through the current open circuit voltage and instantaneous DC resistance. Similarly, the discharge depth after the target continuous discharge time under the current operating conditions is predicted, and the open circuit voltage and continuous DC resistance after the target continuous discharge time can be obtained by, for example, looking up a table. The continuous maximum discharge current can be calculated through the open circuit voltage and continuous DC resistance after the target continuous discharge time. As mentioned above, the relationship table between the open circuit voltage and the discharge depth can be stored in the battery pack; in one embodiment, the method in this application can be used to adaptively learn and update the impedance curve, so as to query more accurate instantaneous DC resistance and continuous DC resistance.

[0147] S630: Determine a second reference value of the discharge capability parameter based on the discharge depth constraint.

[0148] The second reference value follows the capacity definition of the battery pack and is determined based on the remaining capacity and target discharge duration of the battery pack. Specifically, the state of charge of the battery pack is first calculated based on the current and voltage. Then, the remaining capacity of the battery pack is obtained based on the state of charge and the maximum chemical capacity of the aged battery pack. Based on the remaining capacity of the battery pack and the set target discharge duration, the instantaneous maximum discharge current and continuous maximum discharge current of the battery pack can be calculated. In one embodiment, the method of this application can be used to learn and update the maximum chemical capacity of the battery pack when conditions permit.

[0149] S640: Determine a third reference value of the discharge capability parameter based on the first reference value and the second reference value.

[0150] The third reference value is calculated by combining the first and second reference values ​​using mathematical statistical methods. In one embodiment, the third reference value is the smaller of the first and second reference values; in one embodiment, the third reference value is the average of the first and second reference values; in one embodiment, the third reference value is the smaller of the first and second reference values ​​plus an adjustment; in one embodiment, the third reference value is the average of the first and second reference values ​​minus the adjustment. There are many specific calculation methods, which can be experimentally sampled for specific power tools and selected using appropriate statistical methods. These methods will not be detailed here.

[0151] S650: Limit the third reference value based on the temperature to determine a discharge capacity parameter.

[0152] refer to Figure 10According to the principle, when the temperature of the battery pack is between [T1, T2] or [T3, T4], the discharge capacity parameter of the battery pack is limited to smoothly transition between 0 and the third reference value, for example, proportional limiting is performed. It can be understood that the temperature of the battery pack may mainly refer to the temperature of its battery cells. The temperature of the battery cell may refer to the surface temperature of the battery cell or the internal temperature of the battery cell. The surface temperature of the battery cell can be measured by a temperature measuring element (for example, an NTC temperature sensor), and the internal temperature of the battery cell can be calculated by a recursive algorithm using a heat conduction effect formula. The temperature of the battery pack may be based on the temperature of the hottest battery cell, or other statistical methods such as the average temperature of the battery cell.

[0153] After the above steps, the discharge capacity parameters of the current battery pack can be determined. Exemplarily, the discharge capacity parameters include instantaneous maximum discharge current and / or continuous maximum discharge current. The power tool can control the discharge of the battery pack based on the discharge capacity parameters. It can be understood that the above steps are a schematic combination, based on the learned aged battery capacity and internal resistance, while taking into account the battery's discharge depth constraint, cut-off voltage constraint, sampling temperature constraint, and estimated battery internal temperature constraint to estimate the instantaneous and continuous maximum discharge capacity. In some embodiments, those skilled in the art may also delete the above steps, for example, removing S650, that is, not considering the impact of the battery pack temperature on the current battery pack's discharge capacity, and only calculating the battery pack's discharge capacity based on the battery pack's current and voltage; for example, only based on the first reference value calculated based on the voltage constraint or only based on the second reference value calculated based on the discharge depth constraint, rather than comprehensively selecting the reference values ​​calculated based on these two constraints.

[0154] In one embodiment, the discharge capacity parameters of the battery pack can also be accurately compensated based on the closed-loop control concept. Figure 13 , the present application further provides a method for determining the discharge capacity parameters of a battery pack, comprising: S710: Obtain status parameters of the battery pack through a detection component.

[0155] The battery pack status parameters include at least one of the battery pack's current information, voltage information, and temperature information. The battery pack status parameters can be obtained from a detection component. As previously described, the detection component can be partially or fully incorporated into the battery pack or the power tool, and will not be further described here.

[0156] S720: Determine the discharge capacity parameter according to the state parameter.

[0157] In this step, the discharge capability parameters of the battery pack can be determined by referring to the methods described in S610-S650 above or other methods. The discharge capability parameters include at least one of a first discharge capability parameter and a second discharge capability parameter. The first discharge capability parameter is the discharge capability of the battery pack when controlling instantaneous discharge to a cutoff voltage; the second discharge capability parameter is the discharge capability of the battery pack when controlling continuous discharge to the cutoff voltage. Exemplarily, the discharge capability parameters include instantaneous maximum discharge current and / or continuous maximum discharge current.

[0158] S730: Limit the discharge of the battery pack according to the discharge capacity parameter, and then obtain the voltage of the battery pack again.

[0159] In this step, the power tool controls the discharge of the battery pack with the discharge capacity parameter determined in step S720 as the limit value, and then obtains the voltage of the battery pack again. In actual practice, the conventional parameters such as voltage, current, and temperature of the battery pack are generally continuously detected and obtained by the detection component. The voltage obtained again here may not only be the result of a single detection, but the result of statistical analysis of the detection results of a time period. The emphasis is on the current terminal voltage of the battery pack after a certain period of control according to the discharge capacity parameter determined in step S720.

[0160] S740: Update the discharge capacity parameter according to the difference between the voltage obtained again and the cut-off voltage of the battery pack.

[0161] Specifically, the difference between the current terminal voltage and the cutoff voltage is compared, and the discharge capacity parameters are adjusted in combination with the internal resistance of the battery pack. When the current terminal voltage is greater than the cutoff voltage, it indicates that the previously determined discharge capacity parameters are conservative. In other words, the discharge capacity parameters, such as the instantaneous maximum discharge current and / or the continuous maximum discharge current, can be increased. The specific value of the compensation value is calculated based on the difference between the current terminal voltage and the cutoff voltage and the internal resistance of the battery pack. When the current terminal voltage is less than the cutoff voltage, it indicates that the previously determined discharge capacity parameters are optimistic. In other words, the discharge capacity parameters, such as the instantaneous maximum discharge current and / or the continuous maximum discharge current, need to be reduced. The specific value of the compensation value is calculated based on the difference between the current terminal voltage and the cutoff voltage and the internal resistance of the battery pack.

[0162] In the actual use of the power tool, it is not necessary to discharge the battery pack at its maximum capacity all the time. In one embodiment, the operating conditions where the discharge does not reach the discharge capacity parameter can be timed, and the weight of the compensation value can be determined based on the timing. For example, when the proportion of operating conditions where the discharge does not follow the discharge capacity parameter is relatively high, the weight of the compensation value can be reduced. Figure 13As shown, S730 and S740 can be executed multiple times in a loop to compensate and update the discharge capacity parameter in real time. The above-mentioned method for determining the discharge capacity parameter can be executed by the first controller 12 of the battery pack 1 or the second controller 21 of the power tool 2.

[0163] This application also proposes a new concept of state of charge. The conventional state of charge (SOC) is the ratio of a battery's remaining capacity after a period of use or long-term inactivity to its capacity in a fully charged state, often expressed as a percentage. Its value ranges from 0 to 1, with SOC = 0 indicating a fully discharged battery and SOC = 1 indicating a fully charged battery. The sum of the conventional state of charge (SOC) and depth of discharge (DOD) equals 1. That is, at a DOD of 60%, the SOC is 40%, and at a DOD of 40%, the SOC is 60%. The fully charged capacity refers to the battery's maximum chemical capacity, which does not include capacity lost during aging. Therefore, even if a battery has aged, for example, with a maximum chemical capacity of only 80% of its initial chemical capacity, the SOC can still reach 1 when fully charged. However, not all operating conditions allow the battery's full chemical capacity to be fully discharged. This means that when using some electrical equipment, such as power tools, users may find that even if the SOC is not 0, they cannot continue to discharge the battery. In particular, when using some high-current power tools, such as chainsaws and snow blowers, it is impossible to completely discharge the battery's SOC to 0. Therefore, the conventional definition of SOC can sometimes cause confusion or trouble for users, making it difficult for them to properly assess the power requirements of the power tools and other electrical equipment they need to use.

[0164] In order to solve this problem, the present application proposes the concept of relative state of charge (RSOC). The relative state of charge RSOC is defined as the ratio of the remaining dischargeable capacity of the battery under the current operating conditions to the maximum capacity that the battery can discharge under the current operating conditions (maximum discharge capacity); wherein, the remaining dischargeable capacity of the battery under the current operating conditions is the difference between the maximum dischargeable capacity of the battery under the current operating conditions (maximum discharge capacity) and the discharged capacity (cumulative discharge capacity). Alternatively, the relative state of charge RSOC can also be defined as the ratio of the remaining discharge depth of the battery under the current operating conditions to the discharge depth of the battery at the end of discharge under the current operating conditions; wherein, the remaining discharge depth of the battery under the current operating conditions is the difference between the discharge depth of the battery at the end of discharge under the current operating conditions and the discharge depth at the current moment.

[0165] Theoretically, the relative state of charge RSOC under the current operating conditions can be calculated not only during discharge, but also during charging at the current charging current / rate; however, charging equipment often adjusts the charging current / rate according to the charging state of the battery pack, while discharging equipment mainly discharges according to the needs of the discharge work. By estimating the relative state of charge RSOC of the battery pack during discharge, devices that use the power of the battery pack, such as power tools, can optimize the discharge process in combination with the current operating conditions and the relative state of charge RSOC. In one embodiment, the relative state of charge RSOC of the battery pack can also be provided to the user through a display device on the battery pack or electrical equipment, or through a mobile terminal such as a mobile phone, so that the user can reasonably evaluate the power demand and carry a sufficient number of battery packs.

[0166] Based on the same concept, this application also proposes a method for estimating the relative state of charge of a battery pack. The battery pack 1 includes: a housing 14; a plurality of battery cells 15 housed within the housing 14; a power tool interface 13 disposed within the housing 14; and a first circuit board 16 housed within the housing 14 and electrically connected to the power tool interface 13. The first circuit board 16 is provided with a first controller 12. The estimation method includes: obtaining the voltage and current of the battery pack 1 through a detection component 11; determining the current depth of discharge of the battery pack 1 based on the voltage and current of the battery pack 1; determining the end-point depth of discharge of the battery pack 1 under current operating conditions based on the voltage and current of the battery pack 1 and the current depth of discharge; and calculating the relative state of charge of the battery pack 1 under current operating conditions based on the current depth of discharge and the end-point depth of discharge. In one embodiment, the relative state of charge is the ratio of the difference between the end-point depth of discharge and the current depth of discharge to the end-point depth of discharge. The specific calculation process for the current depth of discharge and the endpoint depth of discharge, as well as the calculation process for their intermediate variables, can be found in other sections of this application. A brief description is provided below: In one embodiment, the current depth of discharge of the battery pack 1 is determined based on the voltage and current of the battery pack 1, including: calculating an initial depth of discharge based on the voltage of the battery pack 1 when the battery pack 1 is at rest; and calculating the current depth of discharge based on the initial depth of discharge, the maximum chemical capacity of the battery pack 1, and the current. In one embodiment, the maximum chemical capacity of the battery pack 1 is determined based on the initial chemical capacity and overall health of the battery pack 1. In one embodiment, the endpoint of discharge is defined as when the voltage of the battery pack 1 reaches the discharge cutoff voltage, and the endpoint depth of discharge is the discharge depth corresponding to the voltage at the discharge cutoff voltage. In one embodiment, the endpoint depth of discharge of the battery pack 1 under current operating conditions is determined based on the voltage and current of the battery pack 1 and the current depth of discharge, including: adaptively learning an impedance curve under current operating conditions based on the voltage and current of the battery pack 1 and the current depth of discharge; determining a voltage change curve of the battery pack 1 under current operating conditions based on the impedance curve and the current depth of discharge; and determining the endpoint depth of discharge based on the voltage change curve and the discharge cutoff voltage.

[0167] Based on the same concept, this application also proposes another method for estimating the relative state of charge of a battery pack. A battery pack 1 includes: a housing 14; a plurality of battery cells 15 housed within the housing 14; a power tool interface 13 disposed within the housing 14; and a first circuit board 16 housed within the housing 14 and electrically connected to the power tool interface 13. The first circuit board 16 is provided with a first controller 12. The estimation method includes: obtaining the voltage and current of the battery pack 1 via a detection component 11; obtaining the cumulative discharge capacity of the battery pack 1 based on the voltage and current of the battery pack 1; obtaining the maximum discharge capacity that the battery pack 1 can discharge under current operating conditions based on the voltage and current of the battery pack 1; and calculating the relative state of charge of the battery pack 1 under current operating conditions based on the cumulative discharge capacity and the maximum discharge capacity. In one embodiment, the relative state of charge is the ratio of the difference between the maximum discharge capacity and the cumulative discharge capacity to the maximum discharge capacity. The specific calculation process of the cumulative discharge capacity and the maximum discharge capacity, as well as the calculation process of their intermediate variables, can be found in other sections of this application. A brief description is provided here as follows: In one embodiment, the cumulative discharge capacity is the product of the maximum chemical capacity of the battery pack 1 and the current depth of discharge of the battery pack 1. In one embodiment, the maximum discharge capacity is the product of the maximum chemical capacity of the battery pack 1 and the end-point depth of discharge of the battery pack 1 under the current operating conditions.

[0168] Based on the same concept, this application also proposes an electrical device system capable of simultaneously providing both the normal state of charge and relative state of charge of a battery pack. This electrical device system includes a battery pack 1 and a host 2. The host 2 can be a power tool 2, a lamp, an energy station, or the like. The battery pack 1 includes a housing 14, a plurality of battery cells 15 housed therein, a power tool interface 13 disposed within the housing 14, and a first circuit board 16 housed within the housing 14. A first controller 12 is disposed on the first circuit board 16. The host 2 includes a housing 24; a battery pack interface 23 disposed within the housing 24 for electrical and communication connection with the power tool interface 13; and a second circuit board 26 housed within the housing 24 and electrically connected to the battery pack interface 13. A second controller 21 is disposed on the second circuit board 26. The electrical device system also includes a detection assembly 11 for detecting at least the voltage and current of the battery pack 1. The detection assembly 11 is disposed within the battery pack housing 14 and / or within the host housing 24. Among them, the first controller 12 or the second controller 21 is respectively communicated with the detection component 11, and is configured to: obtain the voltage and current of the battery pack 1 through the detection component 11; calculate the current discharge depth of the battery pack 1 based on the voltage and current of the battery pack; determine the terminal discharge depth of the battery pack 1 under the current operating conditions based on the voltage and current of the battery pack 1, and the current discharge depth; and determine the charge state of the battery pack and the relative charge state of the battery pack under the current operating conditions based on the current discharge depth and the terminal discharge depth.

[0169] In specific embodiments, see Figures 8A to 8C , the detection component 11 can be entirely set in the battery pack 1, and the first controller 12 can calculate at least one of the state of charge of the battery pack 1 and the relative state of charge of the battery pack 1 under the current operating conditions. The detection component 11 can be distributed in the battery pack 1 and the host 2, and the detection data can be uniformly transmitted to the first controller 12 or the second controller 21, and the first controller 12 or the second controller 21 can calculate at least one of the state of charge of the battery pack 1 and the relative state of charge of the battery pack 1 under the current operating conditions. As an expanded embodiment, the host 2 can also be provided with power not by the battery pack 1 but by the battery cell module 25 built into the host 2. The first controller 12' and the detection component 11 are set in the housing 24 of the host 2, and the first controller 12' or the second controller 21 can calculate at least one of the state of charge of the battery pack 1 and the relative state of charge of the battery pack 1 under the current operating conditions. In one embodiment, the detection component 11 includes a voltage sensor, a current sensor, and a temperature sensor. Optionally, the voltage sensor and the temperature sensor are set in the battery pack 1, and the current sensor is set in the host 2.

[0170] Furthermore, the electrical device system may further include a display device for displaying to a user at least one of the state of charge of the battery pack 1 and the relative state of charge of the battery pack 1 under current operating conditions. The display device may be provided on the battery pack 1, the host 2, or a mobile terminal such as a mobile phone.

[0171] The present application also provides a method for calculating the maximum chemical capacity of a battery pack, which can be used in the above-mentioned maximum chemical capacity update module 431. Conventional methods fully charge and / or fully discharge the battery to obtain the maximum charge / discharge capacity of the battery within a complete charge and / or discharge cycle, that is, the maximum chemical capacity. Conventional methods usually have stable requirements for the current within this complete charge and / or discharge cycle. The experimental conditions are relatively harsh and may not always be met during daily use by users.

[0172] The maximum chemical capacity of the battery pack is equal to the product of the state of health SOH and the initial chemical capacity. Since the initial chemical capacity of the battery pack is fixed, calculating the maximum chemical capacity is actually to calculate the state of health SOH of the battery pack. The present application believes that the overall state of health SOH of the battery can be mapped from a preset mapping model according to the interval health state of the battery. Therefore, the problem of obtaining the overall health state of the battery can be simplified to obtaining the interval health state of the battery. The interval health state can be obtained by comparing the actual charging capacity and the health assessment benchmark value of the preset voltage interval. In one embodiment, the health assessment benchmark value is the theoretical charging capacity of a brand new battery pack in the preset voltage interval. In one embodiment, the interval health state is equal to the ratio of the actual charging capacity to the theoretical charging capacity.

[0173] Based on the above concept, the present application proposes a method for evaluating the health status of a battery pack 1. The battery pack 1 includes: a housing 14; a plurality of battery cells 15 housed in the housing 14; a power tool interface 13 disposed in the housing 14; and a first circuit board 16 housed in the housing 14 and electrically connected to the power tool interface 13. The first circuit board 16 is provided with a first controller 12. Figure 20 , the evaluation methods include: S810: Estimate the health status of the battery pack within a preset voltage range during charging of the battery pack.

[0174] When the battery pack's charging process meets the following conditions, the health status within the preset voltage range can be estimated during this charging process: 1. After a preset period of time has passed since charging began, the battery pack voltage is less than the minimum value of the preset voltage range. The preset time period can be long enough to ensure the battery pack can enter a stable charging state, such as 100s, 200s, or 300s. Alternatively, it can be combined with the charging current, starting with a timer of 50s, 100s, or 200s from the time the rated charging current is reached. In short, it is a time period that ensures the battery pack can enter a stable charging state. If the battery pack voltage exceeds the minimum value of the preset voltage range when entering a stable charging state, the actual charging capacity of the battery pack for the entire preset voltage range cannot be calculated during this charging process, and therefore the interval health status cannot be calculated during this charging process.

[0175] 2. After the preset charging time, the battery pack temperature is within the preset temperature range. The preset temperature range refers to a suitable normal temperature range, and temperatures too high or too low are not acceptable. If the battery pack temperature exceeds the preset temperature range after the preset charging time, indicating that the battery pack temperature is too low or too high, the interval health status cannot be calculated during this charging process.

[0176] 3. A health assessment benchmark value that matches the charging current exists. A battery pack can be connected to and charged by different charging devices. Different charging devices may have different charging logic, current, and rate. Therefore, for the same battery pack, using different charging devices within the same preset voltage range may result in different actual charging capacities. This difference is not due to the health of the battery pack, but rather to different charging conditions. Therefore, different health assessment benchmark values ​​must be selected when charging the battery pack with different charging devices. In one embodiment, the battery pack pre-stores multiple health assessment benchmark values. Since charging devices are not exhaustive, and charging current is the primary difference between different charging devices, a health assessment benchmark value that matches the charging current during the current charge can be found using charging current as a search criterion. In one embodiment, the charging current refers to the average charging current within the preset voltage range. However, when the battery pack is connected to a new charging device, the charging current of the new charging device may differ from the pre-stored charging current. Therefore, no health assessment benchmark value that matches the charging current during the current charge can be found, and the interval health status cannot be calculated for the current charge.

[0177] S820: Determine the overall health status of the battery pack according to the interval health status and a preset mapping model.

[0178] During the production of the battery pack, a mapping model from the interval health status to the overall health status can be established through sampling tests, function fitting, etc., and the mapping model can be pre-stored in the battery pack or charger. The present application does not limit the specific implementation of the preset mapping model. In one embodiment, the overall health status can be a linear or nonlinear function of the interval health status. In one embodiment, a table lookup method can be used to obtain the overall health status from the interval health status. In one embodiment, the preset mapping model can also be combined with parameters such as the resistance and voltage of the battery pack to determine the overall health status of the battery pack. In one embodiment, before implementing step S820, it is necessary to verify the difference between the interval health status estimated in step S810 and the previous interval health status. If the difference is too large, it is considered that the estimated value of the current interval health status is abnormal and will not be adopted.

[0179] When a battery pack is connected to a new charging device and a health assessment baseline value that matches the charging current during the current charge cannot be found, the battery pack can self-learn and store the health assessment baseline value corresponding to the charging current. This health assessment baseline value can be used to estimate the battery pack's interval health status the next time the charging device is used again. Specifically, the health assessment baseline value calculation method includes: calculating the actual charge capacity of the battery pack within a preset voltage range during charging; and calculating the health assessment baseline value of the battery pack within the preset voltage range based on the actual charge capacity and the interval health status stored in the battery pack. The actual charge capacity can be calculated using the ampere-hour integration method. When using a new charging device, assuming that the battery pack's health status has not changed suddenly after the current charge, the health assessment baseline value corresponding to the current charging device, or the current charging current, is calculated based on the previously calculated interval health status of the battery pack. The calculated health assessment baseline value can be stored in the battery pack or charging device.

[0180] The above-described method for assessing the state of health of the battery pack 1 can be executed by the battery pack 1 or the charger 2', specifically by the first controller 12 of the battery pack 1 or the second controller 21' of the charger 2'. A detection component 11 can be provided in at least one of the battery pack 1 and the charger 2'. This detection component 11 may include a voltage sensor, a current sensor, and a temperature sensor for detecting the voltage, charging current, and temperature of the battery pack 1. Pre-stored information such as health assessment baseline values, as well as detected data such as voltage and charging current, can be transmitted from the battery pack 1 to the charger 2', or vice versa, to facilitate the execution of the above-described assessment method. Furthermore, the battery pack 1 or the charger 2' may include a display device for displaying the state of health (SOH) of the battery pack 1 to the user. The display device can be provided on the battery pack 1, the charger 2', or a mobile device such as a mobile phone, allowing the user to understand the aging status of the battery pack 1, thereby enabling better maintenance or timely replacement of the battery pack 1.

[0181] This embodiment also provides a method for reducing lithium plating in a battery pack. When a lithium-ion battery pack for a power tool is charged at low temperatures, high currents, or a high charge state, lithium metal is easily deposited on the surface of the negative electrode material of the battery pack. In severe cases, dendritic lithium dendrites may appear. The application of fast charging technology exacerbates this phenomenon, seriously affecting the lifespan and safety of the battery pack. Therefore, there is an urgent need for a technology that can promptly detect the point at which lithium plating begins in a battery pack and adjust the charging power of the battery pack. This technology can reduce or eliminate lithium plating while maintaining fast charging, thereby improving the lifespan and safety of the battery pack.

[0182] This embodiment provides a method for reducing lithium deposition in a battery pack as follows: During charging of the battery pack, at intervals of a first set time period, the charging current is reduced to a set value and maintained for a second set time period. The change in current ΔI and voltage ΔV of the battery pack during the charging current reduction process is examined, and the charge transfer impedance of the battery pack is calculated based on ΔI and ΔV each time the current is reduced to the set value. The calculated charge transfer impedance of the battery pack is compared with a charge transfer impedance table stored in the battery pack. When the calculated charge transfer impedance is less than the charge transfer impedance corresponding to the corresponding state of charge in the stored charge transfer impedance table, the maximum allowable charging current value of the battery pack is reduced according to a first set rule, and the charge transfer impedance table is updated.

[0183] The first set time period may be set according to the charging state of the battery pack, for example, at least one of the charging temperature, charging current, and state of charge of the battery pack. In some embodiments, the set time period may be 60 seconds.

[0184] The second set time period and the set value can be set according to the characteristics of the battery pack. Within the second set time period, the current of the battery pack can reach the set value. In some embodiments, the second set time period can be 1 second. In some embodiments, the set value can be close to 0.

[0185] In some embodiments, calculating the charge transfer impedance of the battery pack each time the current decreases to a set value based on ΔI and ΔV may include calculating the charge transfer impedance of the battery pack each time the current decreases to the set value based on a second formula. The second formula is: Z = ΔV / ΔI, where Z is the charge transfer impedance of the battery pack.

[0186] The first setting rule can be determined according to actual conditions. In some embodiments, the first setting rule is a fixed value, that is, the maximum charging current value allowed by the battery pack is reduced by a fixed value. In some embodiments, the first setting rule is a variable step size, that is, the maximum charging current value allowed by the battery pack is reduced by a variable step size. Exemplarily, when the calculated charge transfer impedance is less than the charge transfer impedance corresponding to the corresponding state of charge in the stored charge transfer impedance table, the maximum charging current value allowed by the battery pack is reduced by the first step size. When the calculated charge transfer impedance is less than the charge transfer impedance corresponding to the corresponding state of charge in the stored charge transfer impedance table, the maximum charging current value allowed by the battery pack is reduced by the second step size, wherein the first step size is smaller than the second step size.

[0187] Another method for reducing lithium deposition in a battery pack provided by this embodiment is as follows: During charging of the battery pack, the charging current is reduced to a set value at intervals of a first set time period and maintained for a second set time period. The change in current ΔI and voltage ΔV of the battery pack during the charging current reduction process is examined, and the charge transfer impedance of the battery pack is calculated based on ΔI and ΔV each time the current is reduced to the set value. The charge transfer impedance of the battery pack calculated at the current moment is compared with the charge transfer impedance of the battery pack calculated at the previous moment. If the charge transfer impedance of the battery pack calculated for three or more consecutive times is less than the charge transfer impedance of the battery pack calculated at the previous moment, the maximum charging current allowed for the battery pack is reduced according to the second set rule.

[0188] The second setting rule can be set according to actual conditions. In some embodiments, the second setting rule is the same as the first setting rule. In some embodiments, the second setting rule is different from the first setting rule.

[0189] Another method for reducing lithium deposition in a battery pack provided by this embodiment is as follows: during the charging process of the battery pack, the lithium deposition of the battery pack is detected in real time. When lithium deposition is detected in the battery pack, the charging current of the battery pack is reduced according to a third set rule until no lithium deposition is detected in the battery pack.

[0190] Among them, the method of detecting the lithium deposition situation of the battery pack may include, but is not limited to, pulse charging detection charge transfer impedance method, low current method, impedance-capacity method and voltage relaxation method.

[0191] The third setting rule can be set according to actual conditions. In some embodiments, the third setting rule is a fixed value, that is, the charging current of the battery pack is reduced by a fixed value.

[0192] The above shows and describes the basic principles, main features and advantages of this application. Those skilled in the art should understand that the above embodiments do not limit this application in any form, and any technical solutions obtained by equivalent replacement or equivalent transformation fall within the scope of protection of this application.

Claims

1. A method for evaluating the health status of a battery pack (1), the battery pack (1) comprising: housing (14); A plurality of battery cells (15) are housed in the housing (14); An electric tool interface (13) is provided in the housing (14); and a first circuit board (16) is accommodated in the housing (14) and electrically connected to the electric tool interface (13), wherein a first controller (12) is provided on the first circuit board (16); the evaluation method comprises: estimating the interval health state of the battery pack (1) within a preset voltage interval during the charging process of the battery pack (1); and The overall health state of the battery pack (1) is determined according to the interval health state and a preset mapping model.

2. The evaluation method according to claim 1, wherein: The evaluation method further comprises: obtaining the voltage of the battery pack (1) after a preset time period when the battery pack (1) starts charging; if the voltage is less than a minimum value within the preset voltage interval, estimating the interval health state while the charging voltage is within the preset voltage interval.

3. The evaluation method according to claim 1, wherein: The evaluation method further comprises: obtaining the voltage of the battery pack (1) after a preset time period when the battery pack (1) starts charging; if the charging voltage is greater than or equal to a minimum value within the preset voltage interval, then the interval health status is not estimated during this charging process.

4. The evaluation method according to claim 1, wherein: The evaluation method further comprises: obtaining the temperature of the battery pack (1) after a preset time period when the battery pack (1) starts charging; if the temperature of the battery pack (1) exceeds a preset temperature range, the health state of the range is not estimated during the current charging process.

5. The evaluation method according to claim 1, wherein: The evaluation method further comprises: Obtaining the charging current of the battery pack (1) within the preset voltage range; A health assessment reference value of the battery pack (1) within the preset voltage range is searched based on the charging current; if the health assessment reference value corresponding to the charging current cannot be found, the health state of the range is not estimated during this charging process.

6. The evaluation method according to claim 5, characterized in that The evaluation method further comprises: If the health assessment reference value corresponding to the charging current is found: Calculating the actual charging capacity of the battery pack (1) within the preset voltage range; The health status of the interval is estimated according to the actual charging capacity and the health assessment reference value.

7. A method for evaluating the health status of a battery pack (1), the battery pack (1) comprising: housing (14); A plurality of battery cells (15) are housed in the housing (14); An electric tool interface (13) is provided in the housing (14); and a first circuit board (16) is accommodated in the housing (14) and electrically connected to the electric tool interface (13), wherein a first controller (12) is provided on the first circuit board (16); the assessment method includes a method for calculating a health assessment baseline value, the calculation method comprising: Calculating the actual charging capacity of the battery pack (1) within a preset voltage range during the charging process of the battery pack (1); and The health assessment reference value of the battery pack (1) within the preset voltage range is calculated based on the actual charging capacity and the interval health status stored in the battery pack (1).

8. The evaluation method according to claim 7, characterized in that The evaluation method further comprises: Obtaining the charging current of the battery pack (1) within the preset voltage range; Searching for the health assessment reference value of the battery pack (1) within the preset voltage range according to the charging current; If the health assessment reference value corresponding to the charging current cannot be found, the calculation method is called to calculate the health assessment reference value corresponding to the charging current.

9. A charger (2'), configured to execute the evaluation method according to any one of claims 1 to 8.

10. A battery pack (1), the battery pack (1) being used to perform the evaluation method according to any one of claims 1-8.

Images