Battery pack, method for determining discharge capability parameter of battery pack, and electric tool system

Abstract

The invention discloses a battery pack, a method for determining discharge capacity parameters of the battery pack and an electric tool system. 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 method for determining the discharge capacity parameters of the battery pack comprises the following steps: acquiring the voltage and current of the battery pack 1 through a detection assembly; determining a discharge capability parameter according to the voltage and the current of the battery pack; limiting the discharge of the battery pack according to the discharge capability parameter, and then obtaining the voltage of the battery pack again; and according to the difference value between the voltage obtained again and the cut-off voltage of the battery pack, updating the discharge capability parameter. According to the invention, the discharge capability parameter of the battery pack is determined according to the current working condition of the battery pack, and precision compensation is carried out to make the precision more accurate, so that the electric tool can discharge according to the limitation of the discharge capability parameter.

Description

Technical Field

[0001] This application relates to the field of power tool technology, specifically to a battery pack and a method, apparatus, power tool, and system for estimating the charging and discharging completion time of the same battery pack. Background Technology

[0002] Battery packs in power tools have varying capacities based on battery type, number of batteries, and battery health status. Furthermore, the charging and discharging speeds and power of battery packs differ depending on factors such as battery pack capacity, load size, charger characteristics, and usage environment. This can lead to an inability to adjust the load size promptly according to the battery pack's discharge capacity. Insufficient battery power utilization can negatively impact the feel of the power tool, while excessive battery power utilization can adversely affect the battery pack's health and even compromise its safe use.

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

[0004] One object of this application is to solve or at least alleviate some or all of the aforementioned problems. Therefore, one object of this application is to provide a battery pack and a method for determining its discharge capacity parameters, as well as a power tool system.

[0005] To achieve the above objectives, this application adopts the following technical solution: This application provides a method for determining the discharge capacity parameters of a battery pack. The battery pack includes: a housing; multiple battery cells housed within the housing; a power tool interface disposed within the housing; and a first circuit board housed within the housing and electrically connected to the power tool interface. A first controller is disposed on the first circuit board. The method for determining the discharge capacity parameters of the battery pack includes: acquiring the voltage and current of the battery pack through a detection component; determining the discharge capacity parameters based on the voltage and current of the battery pack; limiting the discharge of the battery pack based on the discharge capacity parameters, and then acquiring the voltage of the battery pack again; and updating the discharge capacity parameters based on the difference between the reacquired voltage and the cutoff voltage of the battery pack.

[0006] In one embodiment, 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 is the discharge capability of the battery pack when the battery pack is instantaneously discharged to the cutoff voltage; the second discharge capability parameter is the discharge capability of the battery pack when the battery pack is continuously discharged to the cutoff voltage.

[0007] In one embodiment, a first discharge capability parameter is defined when the target continuous discharge time is less than or equal to a first time threshold; and a second discharge capability parameter is defined when the target continuous discharge time is greater than the first time threshold.

[0008] In one embodiment, the discharge capability parameter is a current limit value or a power limit value.

[0009] In one embodiment, determining the discharge capability parameter based on the voltage and current of the battery pack includes: determining a first reference value for the discharge capability parameter based on voltage constraints; determining a second reference value for the discharge capability parameter based on depth of discharge constraints; determining a third reference value for the discharge capability parameter based on the first and second reference values; and determining the discharge capability parameter by limiting the third reference value based on temperature.

[0010] In one embodiment, the first reference value is determined based on the open-circuit voltage and resistance of the battery pack.

[0011] In one embodiment, the second reference value is determined based on the remaining capacity of the battery pack.

[0012] In one embodiment, the third reference value is the smaller of the first and second reference values.

[0013] In one embodiment, updating the discharge capability parameter includes determining a compensation value for the discharge capability parameter based on the difference and the resistance of the battery pack.

[0014] In one embodiment, updating the discharge capability parameter further includes: timing the discharge conditions that fail to meet the discharge capability parameter, and determining the weight of the compensation value based on the timing.

[0015] This application provides a battery pack, including: a housing; multiple battery cells housed within the housing; a detection component for detecting state parameters of the battery pack; a first circuit board housed within the housing, on which a first controller is disposed; the first controller is communicatively connected to the detection component, and the first controller is configured to: acquire the state parameters of the battery pack; and determine the discharge capacity parameters of the battery pack based on the state parameters; wherein the discharge capacity parameters include at least one of a first discharge capacity parameter and a second discharge capacity parameter; the first discharge capacity parameter includes the discharge capacity of the battery pack when the battery pack is instantaneously discharged until the state of the battery pack meets a cutoff condition; the second discharge capacity parameter includes the discharge capacity of the battery pack when the battery pack is continuously discharged until the state of the battery pack meets a cutoff condition. The battery pack also includes a power tool interface electrically connected to the first controller; the power tool interface is used to couple with a power tool to send the discharge capacity parameters to the power tool.

[0016] In one embodiment, the discharge capability parameter includes a current limit value or a power limit value.

[0017] In one embodiment, the state parameters include the current, voltage, and temperature of the battery pack; the first controller is specifically configured to: calculate the state of charge of the battery pack based on the current and voltage; determine the instantaneous DC resistance and / or continuous DC resistance of the battery pack based on the state of charge and temperature; determine a first discharge capability parameter based on a cutoff condition and the instantaneous DC resistance of the battery pack; and / or determine a second discharge capability parameter based on a cutoff condition and the continuous DC resistance.

[0018] In one embodiment, the first controller is further configured to: determine the instantaneous voltage before discharge and the continuous voltage before discharge of the battery pack based on the current; determine a first discharge capability parameter based on the instantaneous voltage before discharge, a 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; wherein the first discharge capability parameter and the second discharge capability parameter include a current limit value.

[0019] In one embodiment, the state parameters include the current, voltage, and temperature of the battery pack; the first controller is specifically configured to: determine a first reference value for the discharge capability parameter based on voltage constraints; determine a second reference value for the discharge capability parameter based on depth of discharge constraints; determine a third reference value based on the first and second reference values; and determine the discharge capability parameter by limiting the third reference value based on temperature.

[0020] This application also provides an electric tool system, including: a battery pack, comprising: a housing; a plurality of battery cells housed within the housing; an electric tool interface disposed within the housing; and a first circuit board, housed within the housing and electrically connected to the electric tool interface, the first circuit board having a first controller disposed thereon; an electric tool, comprising: a housing; a battery pack interface disposed within the housing for electrical and communication connection with the electric tool interface; and a second circuit board, housed within the housing and electrically connected to the battery pack interface, the second circuit board having a second controller disposed thereon; and a detection component, at least for detecting the voltage and current of the battery pack, the detection component being disposed within the housing of the battery pack and / or the housing of the electric tool; The feature is that the first controller or the second controller is communicatively connected to the detection component and configured to: acquire the voltage and current of the battery pack; determine the discharge capacity parameters of the battery pack based on the voltage and current of the battery pack; wherein the discharge capacity parameters include at least one of a first discharge capacity parameter and a second discharge capacity parameter; the first discharge capacity parameter includes the discharge capacity of the battery pack when the battery pack is instantaneously discharged until the state of the battery pack meets the cutoff condition; the second discharge capacity parameter includes the discharge capacity of the battery pack when the battery pack is continuously discharged until the state of the battery pack meets the cutoff condition; wherein the second controller is further configured to: control the power tool to discharge based on the discharge capacity parameters.

[0021] In one embodiment, when the first controller is configured to determine the discharge capacity parameters of the battery pack, it further sends the discharge capacity parameters to the second controller via the power tool interface and the battery pack interface.

[0022] In one embodiment, after the second controller controls the power tool to discharge according to the discharge capability parameters, the first controller or the second controller is further configured to: acquire the voltage of the battery pack again; and update the discharge capability parameters according to the difference between the acquired voltage and the cutoff voltage of the battery pack.

[0023] In one embodiment, updating the discharge capability parameter includes determining a compensation value for the discharge capability parameter based on the difference and the resistance of the battery pack.

[0024] In one embodiment, updating the discharge capability parameter further includes: timing the discharge conditions that fail to meet the discharge capability parameter, and determining the weight of the compensation value based on the timing.

[0025] The advantages of this application are: it can determine the discharge capacity parameters of the battery pack based on the current operating conditions of the battery pack, and perform precision compensation on the discharge capacity parameters to make them more accurate; it also facilitates power tools to discharge according to the limitations of the battery pack's discharge capacity parameters. Attached Figure Description

[0026] Figure 1 A flowchart illustrating a method for estimating the charging and discharging completion time of a battery pack, as provided in an embodiment of this application; Figure 2 A schematic diagram of the voltage change curve of a battery pack provided in an embodiment of this application; Figure 3 A flowchart illustrating another method for estimating the charging and discharging completion time of a battery pack, provided in an embodiment of this application; Figure 4 A structural block diagram of a device for calculating the charging and discharging completion time of a battery pack, provided in an embodiment of this application; Figure 5 A flowchart illustrating another method for calculating the charging and discharging completion time of a battery pack, provided in an embodiment of this application; Figure 6 A schematic diagram of an impedance curve provided for an embodiment of this application; Figure 7 A structural block diagram of a device for calculating the charge / discharge completion time of another battery pack provided in an embodiment of this application; Figure 8A A structural block diagram of a power tool system provided in an embodiment of this application; Figure 8B A structural block diagram of another power tool system provided in an embodiment of this application; Figure 8CA structural block diagram of another power tool system provided in the embodiments of this application; Figure 9 A curve showing the relationship between the cutoff voltage and the temperature of a battery pack is provided for an embodiment of this application. Figure 10 A curve showing the relationship between the limiting current of a battery pack and the temperature of the battery pack is provided in an embodiment of this application. Figure 11 A flowchart illustrating a method for determining the discharge capacity parameters of a battery pack, as provided in an embodiment of this application; Figure 12 A flowchart illustrating another method for determining the discharge capacity parameters of a battery pack, provided in an embodiment of this application; Figure 13 A flowchart illustrating another method for determining the discharge capacity parameters of a battery pack, provided in an embodiment of this application; Figure 14 A structural diagram of an electrical equipment system provided in an embodiment of this application; Figure 15 for Figure 14 A schematic diagram of some structures of power tools in the diagram; Figure 16 for Figure 14 A structural diagram of the battery pack in the diagram; Figure 17 for Figure 14 Exploded view of the battery pack in the image; Figure 18 A structural diagram of another electrical equipment system provided in this application embodiment; Figure 19 for Figure 18 A structural diagram of the charger in the image; Figure 20 A flowchart illustrating a method for assessing the health status of a battery pack, as provided in an embodiment of this application; Figure 21 A statistical chart showing the predicted and actual charging completion time of a battery pack, provided for embodiments of this application; Figure 22 A statistical chart showing the predicted and actual discharge completion time of a battery pack, provided for embodiments of this application. Detailed Implementation

[0027] Before explaining any implementation of this application in detail, it should be understood that this application is not limited to its application to the structural details and component arrangements set forth in the following description or shown in the above drawings.

[0028] In this application, the terms "comprising," "including," "having," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0029] In this application, the term "and / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent three cases: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this application generally indicates that the preceding and following related objects have an "and / or" relationship.

[0030] In this application, the terms "connection," "combination," "coupling," and "installation" can 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, while an indirect connection refers to two parts or components each being connected to at least one intermediary, with the connection achieved through the intermediary. Furthermore, "connection" and "coupling" are not limited to physical or mechanical connections or couplings, but can also include electrical connections or couplings.

[0031] In this application, those skilled in the art will understand that relative terms (e.g., “about,” “approximately,” “basically,” etc.) used in conjunction with quantities or conditions are to include the values ​​and have the meaning indicated by the context. For example, such relative terms include at least the degree of error associated with the measurement of a particular value, tolerances associated with the particular value due to manufacturing, assembly, use, etc. Such terms should also be considered as disclosing a range defined by the absolute values ​​of the two endpoints. Relative terms may refer to 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. Furthermore, “basically” when expressing relative angular relationships (e.g., substantially parallel, substantially perpendicular) may refer to a certain degree (e.g., 1 degree, 5 degrees, 10 degrees or more) added to or subtracted from the indicated angle.

[0032] In this application, those skilled in the art will understand that the function performed by a component can be performed by one component, multiple components, one part, or multiple parts. Similarly, the function performed by a part can also be performed by one part, one component, or a combination of multiple parts.

[0033] In this application, the directional terms "upper," "lower," "left," "right," "front," and "rear" are used to describe the orientation and positional relationships shown in the accompanying drawings and should not be construed as limiting the embodiments of this application. Furthermore, in the context, it should be understood that when an element is mentioned as being connected "upper" or "lower" to another element, it can be directly connected to the other element "upper" or "lower," or indirectly connected through an intermediate element. It should also be understood that directional terms such as upper side, lower side, left side, right side, front side, and rear side not only represent positive orientation but can also be understood as lateral orientation. For example, "below" can include directly below, lower left, lower right, lower front, and lower rear.

[0034] In this application, the terms "controller control module", "processor", "central processing unit", "CPU", and "MCU" are used interchangeably. When using the unit "controller", "processor", "central processing unit", "CPU", or "MCU" to perform a specific function, unless otherwise stated, these functions may be performed by a single or multiple of the aforementioned units.

[0035] In this application, the terms "device," "module," or "unit" are used to describe devices that can be implemented in hardware or software to perform a specific function.

[0036] In this application, the terms “calculation,” “judgment,” “control,” “determine,” “identify,” etc., refer to the operation and process of a computer system or similar electronic computing device (e.g., controller, processor, etc.).

[0037] To clearly illustrate the technical solution of this application, the terms "upper side", "lower side", "left side", "right side", "front side" and "rear side" are defined in the accompanying drawings.

[0038] Figures 14 to 19The diagram illustrates the structure of an electrical equipment system provided in this application. The system includes a battery pack 1 and a host unit 2. The battery pack 1 is coupled to the host unit 2 and is capable of transmitting electrical energy to the host unit 2. In one embodiment, the electrical equipment system can be a power tool system, where the host unit 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 within the housing 14, a power tool interface 13 disposed on 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 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 connections. The power tool 2 also includes a housing 24, where the battery pack interface 23 is disposed. A second circuit board 26 is housed within the housing 24, and a second controller 21 is disposed on the second circuit board 26 for controlling the power tool 2. In another embodiment, the electrical equipment system can also be a charging system, where the host unit 2 is a charger 2'. The charger 2' includes a housing 24' and a battery pack interface 23' disposed within the housing 24'. The housing 24' houses a second circuit board 26', on which a second controller 21' is mounted for controlling the charger 2'. This electrical device system or its components (e.g., battery pack 1, host 2) can execute the algorithm provided in this application to estimate and evaluate the battery pack 1's state of health (SOH), state of charge (SOC), discharge capability parameter (SOP), and charge / discharge completion time, etc. The illustrated charger 2' has two battery pack interfaces 23', allowing simultaneous charging of two battery packs and evaluation of their relevant parameters. Hosts with other numbers of battery pack interfaces can also use the algorithm provided in this application.

[0039] Figure 1 This is a flowchart illustrating a method for estimating the charge / discharge completion time of a battery pack, provided in an embodiment of this application. This embodiment provides a method for estimating the charge / discharge completion time of a battery pack, which can be executed by a calculation device for the charge / discharge completion time of the battery pack. This device can be implemented in hardware and / or software. (Reference) Figure 1 As shown, the method includes: S110: Based on data obtained from voltage and current sensors, calculate the depth of discharge of the battery pack in real time.

[0040] The battery pack includes a detection component, which comprises a voltage sensor and a current sensor. The voltage sensor acquires real-time voltage data of the battery pack, including, but not limited to, voltage information in the battery pack's resting state and voltage information during charging and discharging. The voltage information in the battery pack's resting state is the open-circuit voltage of the battery pack, and the open-circuit voltage at different depths of discharge can be pre-determined and stored in the battery pack. The current sensor acquires real-time current data of the battery pack.

[0041] The battery pack's charge / discharge completion time can be understood as the time required for the battery pack to reach the charging cutoff condition during charging, or the time required for the battery pack to reach the discharging cutoff condition during discharging. In one optional embodiment, the charging cutoff condition is the charging cutoff voltage. In one optional embodiment, the discharging cutoff condition is the discharging cutoff voltage. In one optional embodiment, the charging cutoff condition is the charging cutoff SoC. In one optional embodiment, the discharging cutoff condition is the discharging cutoff SoC.

[0042] The depth of discharge (DoD) of a battery pack refers to the percentage of the battery pack's discharge amount to its rated capacity. When the battery pack is at rest, the DoD is a fixed value. In one optional embodiment, when the battery pack is at rest, the DoD is obtained based on voltage information acquired by a voltage sensor, i.e., the open-circuit voltage of the battery pack, and a table showing the relationship between open-circuit voltage and DoD. When the battery pack is charging or discharging, its voltage changes dynamically. In one optional embodiment, when the battery pack is charging, the DoD is obtained based on the DoD of the battery pack at the previous moment and the increase in charge during the time interval from the previous moment to the current moment. The increase in charge during the time interval is obtained from the current information during that time interval. In one optional embodiment, when the battery pack is discharging, the DoD is obtained based on the DoD of the battery pack at the previous moment and the decrease in charge during the time interval from the previous moment to the current moment. The decrease in charge of the battery pack during the time period from the previous moment to the current moment is obtained from the current information during that time period.

[0043] S120. Based on the impedance curve and depth of discharge of the battery pack, determine the voltage change curve of the battery pack.

[0044] The impedance curve of the battery pack can be a pre-measured and stored curve of the internal resistance of the battery pack at different depths of discharge. In one embodiment, the impedance value of the impedance curve is a normalized impedance value decoupled from the temperature effect; this impedance curve, combined with the temperature prediction curve of the battery pack, can generate an impedance curve that includes the temperature effect. 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 of the battery pack at different depths of discharge can be predicted, i.e., the voltage change curve.

[0045] Figure 2 This is a schematic diagram of the voltage change curve of a battery pack provided in an embodiment of this application. In an optional embodiment, based on the impedance curve of the battery pack and the real-time calculated depth of discharge of the battery pack, as well as the open-circuit voltage of the battery pack at different depths of discharge, the voltage of the battery pack corresponding to the depth of discharge of each battery pack after the current moment is simulated and calculated, forming a voltage curve as shown in the figure. Figure 2 The voltage variation curve of the battery pack is shown.

[0046] S130. Determine the depth of discharge at the end of the charge / discharge cycle of the battery pack based on the voltage change curve and the charge / discharge cutoff voltage of the battery pack.

[0047] The depth of discharge at the end of the charge / discharge cycle of the battery pack refers to the depth of discharge at which the battery pack reaches the charging cutoff condition during charging, or the depth of discharge at which the battery pack reaches the discharging cutoff condition during discharging. In one optional embodiment, the charging cutoff condition is the charging cutoff voltage. In another optional embodiment, the discharging cutoff condition is the discharging cutoff voltage.

[0048] Specifically, after the voltage change curve is generated, it is compared with the charge / discharge cutoff voltage of the battery pack. The discharge depth corresponding to the charge / discharge cutoff voltage of the battery pack in the voltage change curve is taken as the discharge depth at the end of the charge / discharge of the battery pack.

[0049] S140. Calculate the charging and discharging completion time of the battery pack based on the discharge depth at the end of the charging and discharging process and the discharge depth at the current moment.

[0050] Specifically, the battery pack charge / discharge completion time refers to the time required for the battery pack's depth of discharge to increase from the current depth of discharge to the final depth of discharge. During battery pack charging, the charge completion time refers to the time required for the battery pack's depth of discharge to reach the final depth of discharge. During battery pack discharging, the discharge completion time refers to the time required for the battery pack's depth of discharge to reach the final depth of discharge.

[0051] Specifically, based on data acquired from voltage and current sensors—namely, voltage and current data—the depth of discharge of the battery pack is calculated in real time. Then, based on the battery pack's impedance curve and depth of discharge, the voltage variation curve is determined. Next, based on the voltage variation curve and the battery pack's stored charge / discharge cutoff voltage, the depth of discharge at the end of the charge / discharge cycle is determined. Finally, based on the depth of discharge at the end of the charge / discharge cycle and the current depth of discharge, the charge / discharge completion time of the battery pack can be calculated. This allows for real-time updates to the charge / discharge completion time, improving the accuracy of the estimated completion time.

[0052] In this embodiment, the depth of discharge of the battery pack is calculated in real time based on data acquired by voltage and current sensors of the battery pack. This allows for the determination of the battery pack's voltage change curve based on the impedance curve and the depth of discharge. Then, the depth of discharge at the end of the charge / discharge cycle is determined according to the voltage change curve and the battery pack's charge / discharge cutoff voltage. Finally, the charge / discharge completion time is calculated based on the end-of-charge / discharge depth and the current depth of discharge. This allows the charge / discharge completion time to be calculated based on the real-time state of the battery pack, making it unaffected by battery capacity, load size, charger characteristics, and operating environment. This improves the accuracy of the estimated completion time calculation for a charging / discharging battery pack, thereby enhancing the user experience.

[0053] Optional, Figure 3 This is a flowchart illustrating another method for estimating the charge / discharge completion time of a battery pack, provided as an embodiment of this application. Based on the above embodiments, this embodiment further adds steps on how to calculate the depth of discharge of the battery pack, how to determine the voltage change curve of the battery pack, how to determine the depth of discharge at the end of the charge / discharge cycle, and how to calculate the charge / discharge completion time of the battery pack. (Reference) Figure 3 As shown, the method specifically includes: S210. Based on the voltage information of the battery pack obtained by the voltage sensor when the battery pack is stationary, determine the initial depth of discharge.

[0054] Here, "battery pack at rest" can be understood as the battery pack neither being charged nor 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 that moment.

[0055] In one optional embodiment, a voltage sensor acquires the open-circuit voltage of the battery pack at different depths of discharge and stores it in the battery pack. Before charging or discharging begins, the voltage sensor acquires the voltage information of the battery pack 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 voltages at different depths of discharge stored in the battery pack.

[0056] S220: Calculates the current depth of discharge based on the initial depth of discharge, the maximum chemical capacity of the battery pack, and data obtained from the current sensor.

[0057] The maximum chemical capacity of the battery pack can be understood as the chemical capacity of the battery pack when fully charged. The data acquired 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 acquired by the current sensor. For example, during the charging process, the amount of charge added to the battery pack per unit time is calculated based on the current data acquired by the current sensor. During the discharging process, the amount of charge removed from the battery pack per unit time is calculated based on the current data acquired 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. Thus, the change in depth of discharge can be calculated by the ratio of the increase / decrease in charge to the maximum chemical capacity of the battery pack. Combined with the initial depth of discharge of the battery pack, the depth of discharge of the battery pack in real time can be obtained, thereby improving the accuracy of the obtained depth of discharge of the battery pack, and thus improving the accuracy of the calculation of the battery pack charge / discharge completion time.

[0058] In one 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, it is determined that the battery pack is charging. Conversely, when the direction of the current in the battery pack is negative, it is determined that the battery pack is discharging.

[0059] S230. Starting from the current depth of discharge, the voltage of the battery pack is simulated and calculated using a variable step size, and a voltage change curve is generated.

[0060] Specifically, starting from the current depth of discharge, the simulation is performed by stepping with a variable step size, gradually adding different depths of discharge, and simulating the voltage of the battery pack at different depths of discharge under future loads to form a voltage change curve.

[0061] In one 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.

[0062] S240. During the charging process of the battery pack, the depth of discharge corresponding to the charging cutoff voltage in the voltage change curve is taken as the depth of discharge at the end of the charging of the battery pack; and the depth of discharge corresponding to the discharge cutoff voltage in the voltage change curve is taken as the depth of discharge at the end of the discharge of the battery pack.

[0063] The charging cutoff voltage can be understood as the maximum voltage of the battery pack. When the battery pack voltage reaches the charging cutoff voltage, the charging is stopped to protect the battery pack. In an optional embodiment, the charging cutoff voltage is the factory-set charging cutoff condition for the battery pack, which can be the voltage when the battery pack is fully charged. In some embodiments, the charging cutoff voltage can be a user-developed charging cutoff condition, which is the voltage set by the user according to their needs via a button or client application. For example, if the user's requirement is for the battery pack to have the largest possible capacity, the charging cutoff voltage can be set to the voltage when the battery pack is fully charged. Conversely, if the user's requirement is to extend the battery pack's lifespan, the charging cutoff voltage can be set to be lower than the voltage corresponding to a fully charged battery pack.

[0064] The discharge cutoff voltage can be understood as the minimum voltage set for the battery pack. When the battery pack voltage reaches the discharge cutoff voltage, the battery pack stops discharging to protect it. Similar to the charging cutoff voltage, the discharge cutoff voltage can be the factory-set discharge cutoff condition for the battery pack, while the charging cutoff condition can be a user-defined condition developed to meet specific needs. The similarities will not be elaborated further.

[0065] Specifically, starting from the current depth of discharge, a voltage change curve is generated through simulation calculation. If the battery pack is charging, the depth of discharge corresponding to the charging cutoff voltage in the voltage change curve is taken as the depth of discharge at the end of charging. If the battery pack is discharging, the depth of discharge corresponding to the discharging cutoff voltage in the voltage change curve is taken as the depth of discharge at the end of discharging. Since the voltage change curve is generated through real-time simulation calculation, the depth of discharge corresponding to the charging / discharging cutoff voltage in the discharge change curve changes in real time with the state of the battery pack at the current moment. This makes the determined depth of discharge at the end of charging / discharging more accurate, thereby improving the accuracy of calculating the charging / discharging completion time of the battery pack.

[0066] S250. Calculate the charging and discharging completion time of the battery pack according to the first calculation formula.

[0067] The first calculation formula is as follows: T = |DOD final -DOD now |*Q max / I now Where T is the charge / discharge completion time. DOD final Depth of discharge (DOD) is the distance between the points where the charge and discharge cycle ends. now Q represents the current depth of discharge. max This refers to the maximum chemical capacity of the battery pack. now This represents the current of the battery pack at the current moment.

[0068] Specifically, the charging and discharging state 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. Then, using the current depth of discharge as a starting point, the voltage of the battery pack is simulated and calculated using a variable step size, generating a voltage change curve. The depth of discharge corresponding to the charging cutoff voltage in the voltage change curve is then taken as the depth of discharge at the end of the charging process. Finally, the charging completion time of the battery pack can be calculated according to the first calculation formula. Similarly, 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. Then, using the current depth of discharge as a starting point, the voltage of the battery pack is simulated and calculated using a variable step size, generating a voltage change curve. The depth of discharge corresponding to the discharge cutoff voltage in the voltage change curve is then taken as the depth of discharge at the end of the charging process. Finally, the discharging completion time of the battery pack can be calculated according to the first calculation formula. In this way, by calculating the status of the battery pack in real time, the charging and discharging completion time of the battery pack can be estimated more accurately, which helps users to reasonably arrange the use time of power tools based on the charging and discharging completion time of the battery pack.

[0069] In this embodiment, by using the current depth of discharge as a starting point and employing a variable step size, the voltage of the battery pack is simulated and calculated, generating a voltage change curve. This curve is updated in real time according to the battery pack's state, making the depth of discharge at the end of the charge / discharge cycle determined by the voltage change curve more accurate, thereby improving the accuracy of the battery pack's charge / discharge completion time. Furthermore, calculating the battery pack's charge / discharge completion time using the first calculation formula simplifies the calculation process, thus saving computational resources.

[0070] Based on the same concept, this application also provides a device for calculating the charge / discharge completion time of a battery pack. This device for calculating the charge / discharge completion time of the battery pack 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 A structural block diagram of a battery pack charging and discharging completion time calculation device provided in this application embodiment, with reference to... Figure 4 As shown, the device for calculating the charging and discharging completion time of the battery pack includes: The depth of discharge determination module 410 is used to calculate the depth of discharge of the battery pack in real time based on the data obtained by the voltage sensor and the current sensor.

[0071] Voltage variation curve determination module 420 is used to determine the voltage variation curve of the battery pack based on the impedance curve and depth of discharge of the battery pack. The charge / discharge endpoint determination module 430 is used to determine the depth of discharge at the end of the charge / discharge cycle of the battery pack based on the voltage change curve and the charge / discharge cutoff voltage of the battery pack.

[0072] The charge / discharge completion time determination module 440 is used to determine the charge / discharge completion time of the battery pack based on the discharge depth at the end of the charge / discharge and the discharge depth at the current moment.

[0073] The battery pack charge / discharge completion time calculation device provided in this application embodiment can execute the battery pack charge / discharge completion time calculation method provided in any embodiment of this application, and has the corresponding functional modules and beneficial effects of the execution method. The similarities can be referred to the above description.

[0074] Figure 5 This is a flowchart illustrating another method for calculating the charge / discharge completion time of a battery pack, provided as an embodiment of this application. This embodiment, based on the above embodiments, further adds steps for updating the impedance curve of the battery pack and updating the maximum chemical capacity of the battery pack. (See reference...) Figure 5 As shown, the method specifically includes: S310 calculates the depth of discharge of the battery pack in real time based on data obtained from voltage and current sensors.

[0075] S320 calculates the battery pack impedance information in real time based on data obtained from voltage and current sensors.

[0076] The battery pack impedance information can be understood as the impedance of the battery pack at the current moment. Specifically, the battery pack impedance is calculated based on voltage data from a voltage sensor and current data from a current sensor.

[0077] In one 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 has elapsed since 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.

[0078] 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 until the terminal voltage of the battery pack stabilizes. In an exemplary embodiment, the preset time is 200 seconds.

[0079] In this embodiment, after a preset time has elapsed since the start of charging / discharging, the impedance information at the current moment is calculated in real time based on the battery pack's terminal voltage, open-circuit voltage, and current, making the obtained impedance information more accurate.

[0080] S330 determines the temperature information of the battery pack based on data obtained from the temperature sensor.

[0081] The detection component also includes a temperature sensor. The temperature sensor is used to acquire the battery pack's temperature information in real time. The temperature information may include the current temperature and a temperature prediction curve. In one embodiment, based on the data acquired by the temperature sensor, the heat generation and temperature change rate of the battery pack are calculated to determine the battery pack's temperature prediction curve.

[0082] S340 updates the impedance curve of the battery pack based on the real-time impedance and temperature information.

[0083] Figure 6 This is a schematic diagram of an impedance curve provided in an embodiment of this application. Specifically, after obtaining the impedance and temperature information of the battery pack, a normalized impedance is calculated based on the real-time acquired impedance and temperature information. 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, calculating the normalized impedance based on real-time acquired impedance and temperature information may include converting the real-time acquired impedance information to 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 impedance. By comparing the difference between the normalized impedance calculated in this instance 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 operating conditions can be obtained, and the battery pack's impedance curve can be updated according to the change ratio. Due to the existence of detection anomalies, it is understandable that certain preset conditions need to be met before updating the battery pack's impedance curve. In an optional embodiment, if the normalized impedance does not meet the preset conditions, the impedance corresponding to the discharge depth in the battery pack's impedance curve is used as the impedance of that discharge depth in the updated impedance curve. The preset conditions may be that the difference between the normalized impedance and the impedance corresponding to the discharge depth in the battery pack's impedance curve is within a first preset range. The first preset range can be set according to actual conditions.

[0084] In one optional embodiment, the impedance curve of the battery pack is updated based on the real-time acquired impedance and temperature information, including performing linear regression on the real-time acquired impedance information to obtain a corrected impedance. Then, the impedance curve of the battery pack is updated based on the corrected impedance and temperature information.

[0085] In an optional embodiment, to reduce the amount of computation, linear regression on the real-time acquired impedance information can be understood as linear regression on the most recent finite set of real-time acquired impedance information. For example, linear regression can be performed on the four most recently acquired impedance information sets to obtain the corrected impedance.

[0086] Specifically, after obtaining the impedance and temperature information of the battery pack, linear regression is performed on the real-time impedance information to obtain the corrected impedance. Then, based on the corrected impedance and temperature information, the normalized impedance is calculated. The impedance curve of the battery pack is updated according to the difference between the normalized impedance and the impedance corresponding to the current discharge depth in the impedance curve.

[0087] S350, based on the impedance curve and depth of discharge of the battery pack, determines the voltage change curve of the battery pack.

[0088] S360. Based on the voltage change curve and the charge / discharge cutoff voltage of the battery pack, determine the depth of discharge at the end of the charge / discharge cycle of the battery pack.

[0089] S370. Update the maximum chemical capacity Q of the battery pack based on current data and depth of discharge. max .

[0090] Specifically, the charge change per unit time can be determined based on the current data acquired by the current sensor. Then, based on the charge change per unit time and the real-time depth of discharge of the battery pack, the maximum chemical capacity of the battery pack is calculated and updated. 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 the difference between the calculated maximum chemical capacity of the battery pack and the maximum chemical capacity stored in the battery pack falling within a second preset range. The second preset range can be set according to actual conditions.

[0091] S380. Calculate the charging and discharging completion time of the battery pack according to the first calculation formula.

[0092] The first calculation formula is as follows: T = |DOD final -DOD now |*Q max / I now Where T is the charge / discharge completion time. DOD final The depth of discharge at the end of the charge / discharge cycle, i.e., the final discharge depth. DOD now Q represents the current depth of discharge, i.e., the current discharge depth. max This refers to the maximum chemical capacity of the battery pack. now This represents the current of the battery pack at the current moment.

[0093] In one optional embodiment, after calculating the charge / discharge completion time of the battery pack, the method further includes smoothing the charge / discharge completion time.

[0094] Smoothing the charge / discharge completion time may include, but is not limited to, removing excessively large or small charge / discharge completion times and normalizing the obtained charge / discharge completion times to reduce the differences between the charge / discharge completion times calculated at different times.

[0095] In this embodiment, the battery pack's impedance information is calculated in real time based on data acquired from voltage and current sensors, and the battery pack's temperature information is determined based on temperature information acquired from a temperature sensor. This allows for the updating of the battery pack's impedance curve based on the real-time impedance and temperature information, resulting in a more accurate voltage change curve. Simultaneously, the battery pack's maximum chemical capacity is updated based on current data and depth of discharge acquired from the current sensor, further improving the accuracy of the battery pack's charge / discharge completion time.

[0096] Optional, Figure 7 A structural block diagram of a battery pack charge / discharge completion time calculation device provided in an embodiment of this application is shown below. Figure 7 As shown, the device for calculating the charging and discharging completion time of the battery pack includes: The depth of discharge determination module 410 is used to calculate the depth of discharge of the battery pack in real time based on the data obtained by the voltage sensor and the current sensor.

[0097] 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 real-time impedance information and temperature information.

[0098] The voltage variation curve determination module 420 is used to determine the voltage variation curve of the battery pack based on the impedance curve and depth of discharge of the battery pack.

[0099] The charge / discharge endpoint determination module 430 is used to determine the depth of discharge at the end of the charge / discharge cycle of the battery pack based on the voltage change curve and the charge / discharge cutoff voltage of the battery pack.

[0100] Maximum chemical capacity update module 431 is used to update the maximum chemical capacity Q of the battery pack based on the current data and depth of discharge obtained by the current sensor. max .

[0101] The charge / discharge completion time determination module 440 is used to calculate the charge / discharge completion time of the battery pack according to the first calculation formula.

[0102] The battery pack charging and discharging completion time calculation device provided in this application embodiment can execute the battery pack charging and discharging completion time calculation method provided in the above embodiment, and has the corresponding functional modules and beneficial effects of the execution method. The similarities can be referred to the above description.

[0103] In one embodiment, Figure 4 and Figure 7 The computing device shown is located in the battery pack 1, for example, a first controller 12. The first controller 12 is communicatively connected to the detection component 11 in the battery pack, for example, to the voltage sensor and current sensor in the battery pack, to acquire voltage and current data. Other information, such as the relationship table between open circuit voltage and depth of discharge, and charge / discharge cutoff voltage, may also be pre-stored in the memory of the battery pack 1.

[0104] In another embodiment, Figure 4 and Figure 7The computing device shown is housed in a host unit 2 coupled to the battery pack 1, such as a second controller 21. The host unit 2 can be a device that discharges the battery pack 1, such as a power tool, lamp, or power station, or a device that charges the battery pack 1, such as a charger or adapter. The host unit 2 includes a housing 24 and a battery pack interface 23 disposed in the housing for coupling the battery pack 1. Optionally, the host unit itself includes a detection component 11, which is communicatively connected to the second controller 21 of the host unit 2. The detection component 11 may include a current sensor to detect the current flowing into or out of the battery pack. Specifically, a charger has a current sensor to detect the charging current supplied to the battery pack by the charger, and a power tool has a current sensor to detect the discharging current discharged from the battery pack by the tool. Optionally, the second controller 21 of the host unit 2 can also be communicatively connected to the detection component 11 within the battery pack 1. The battery pack 1 sends data detected by the detection component 11 within the battery pack to the host unit 2 through the power tool interface 13 and the battery pack interface 23, such as voltage data detected by a voltage sensor and temperature data detected by a temperature sensor. Other information, such as the relationship between open-circuit voltage and depth of discharge, and charge / discharge cutoff voltage, can also be pre-stored in the memory of host 21.

[0105] In some embodiments, the host 2 can store relevant information about different types of battery packs or cells and match them when a battery pack is inserted, thereby calculating the charge / discharge completion time of different types of battery packs. That is, the electrical equipment system composed of the battery pack 1 and the host 2, such as the power tool system composed of the battery pack and the power tool, or the charging system composed of the battery pack and the charger, can also use the battery pack charge / discharge completion time calculation method provided in the above embodiments to calculate the charge / discharge completion time of the battery pack.

[0106] Figure 21 The diagram illustrates the calculation method for the charging and discharging completion time of the battery pack provided by the computing device implementing the above embodiments, and the result graph of the estimated charging completion time of the battery pack and the actual charging completion time of the battery pack. Figure 22 The diagram illustrates a method for calculating the charge / discharge completion time of a battery pack provided by the above embodiments using a computing device, and shows the results of estimating the discharge completion time of the battery pack and comparing it with the actual discharge completion time of the battery pack.

[0107] Figures 8A to 8C A structural block diagram of an electrical equipment system, specifically a power tool system, provided in an embodiment of this application is shown below. 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. (Reference) Figure 8C As shown, the power tool system may also include a power tool 2 and a battery module 25 built into the power tool 2.

[0108] 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. Both the detection component 11 and the power tool interface 13 are 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 send the discharge capacity parameters to the power tool interface 13.

[0109] 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 used to receive discharge capability parameters 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 according to the discharge capability parameters.

[0110] Based on the same concept, this application also provides a battery pack 1, including a housing 14, a detection component 11, a first controller 12, and a power tool interface 13. The detection component 11 is disposed within the housing 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 based on 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 a power tool 2 to send the discharge capacity parameters to the power tool 2.

[0111] The battery pack 1 can be electrically connected to the power tool 2, thereby enabling the battery pack 1 to supply power to the power tool 2.

[0112] Based on the same concept, this application also provides a power tool 2, including 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 communicatively connected to the detection component 11. The second controller 21 is configured to determine the discharge capacity parameters of the energy storage device based on the state parameters, and control the operating state of the power tool 2 based on the discharge capacity parameters. Figure 8A As shown, in an optional embodiment, the energy storage device includes a detachable battery pack 1, and a detection component 11 is disposed inside the housing 14 of the battery pack. The status parameters acquired 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 based on the status parameters, and control the working state of the power tool 2 based on the discharge capacity parameters.

[0113] like Figure 8BAs shown, in an optional embodiment, the energy storage device includes a detachable battery pack 1. A detection component 11 is partially disposed within the housing 14 of the battery pack 1 and partially disposed within the housing 24 of the power tool 2. The status parameters acquired by the detection component 11 disposed within the housing 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 status parameters acquired by the detection component 11 disposed within the housing 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 based on the status parameters and control the working state of the power tool 2 based on the discharge capacity parameters.

[0114] like Figure 8C As shown, in other embodiments, the energy storage device may further include a battery cell 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 located within 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 may also be a single controller integrating the above functions. A detection component 11 is also located within the housing 24 of the power tool 2 and is used to detect the status parameters of the battery cell 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 operating state of the power tool 2 based on its own calculated discharge capacity parameters or those obtained from the first controller 12'.

[0115] In summary, the detection component 11 can be entirely housed within the battery pack 1, partially housed within the battery pack 1 and partially housed within the power tool 2, or entirely housed within 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 cell module 25). The detection component 11 includes a voltage sensor, a current sensor, and a temperature sensor. Optionally, the voltage and temperature sensors are located in the battery pack 1, and the current sensor is located in the power tool 2. Based on the state parameters acquired by the detection component 11, the discharge capacity parameters of the energy storage device are determined, which can be implemented by the first controller 12 or 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 raw or filtered voltage, current, and temperature data to the second controller 21.

[0116] 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 battery pack 1 when it is instantaneously discharged until the voltage of battery pack 1 meets the cutoff condition. The second discharge capability parameter includes the discharge capability of battery pack 1 when it is continuously discharged until the voltage of battery pack 1 meets the cutoff condition.

[0117] In other embodiments, when the energy storage device includes a cell module 25, 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 cell module 25 when it instantaneously discharges until the voltage of the cell module 25 meets the cutoff condition. The second discharge capability parameter includes the discharge capability of the cell module 25 when it continuously discharges until the voltage of the cell module 25 meets the cutoff condition. It should be noted that since the first controller of the cell module 25 has the same function as the first controller of the battery pack, unless otherwise specified, the following description will assume that the energy storage module includes a battery pack.

[0118] 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 both the first discharge capability parameter and the second discharge capability parameter.

[0119] The cutoff condition can be understood as the condition under which battery pack 1 stops discharging. In some embodiments, the discharge cutoff condition can be that the depth of discharge of battery pack 1 is less than or equal to the minimum allowable depth of discharge of battery pack 1. In some embodiments, the discharge cutoff condition can be that the voltage of battery pack 1 is less than or equal to the minimum allowable voltage of battery pack 1. Controlling battery pack 1 to discharge instantaneously until the voltage of battery pack 1 meets the cutoff condition can be understood as obtaining, through state estimation, that battery pack 1 discharges instantaneously from its current state until the state of battery pack 1 meets the cutoff condition, for example, battery pack 1 discharges from its current state within 1 second until the state of battery pack 1 meets the cutoff condition. Controlling battery pack 1 to continuously discharge until the voltage of battery pack 1 meets the cutoff condition can be understood as obtaining, through state estimation, that battery pack 1 continuously discharges from its current state until the state of battery pack 1 meets the cutoff condition, for example, battery pack 1 discharges from its current state within 10 seconds until the state of battery pack 1 meets the cutoff condition.

[0120] In an optional embodiment, the discharge capability 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 for the power tool 2 side simpler.

[0121] At least a portion of the detection component 11, the first controller 12, and the power tool interface 13 are disposed within the housing 14 of the battery pack 1, which protects the components housed therein. The detection component 11 may include, but is not limited to, current sensors, voltage sensors, and temperature sensors, thereby enabling it to detect the state parameters of the battery pack. In an optional embodiment, the state parameters of the battery pack may include, but are not limited to, at least one of the current information, voltage information, and temperature information of the battery pack 1.

[0122] 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 send 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 working state of the power tool according to the discharge capacity parameters received from the battery pack interface 23.

[0123] The power tool 2 includes a motor 22. 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 the current limit value, or controlling the power of the motor 22 in the power tool 2 to be less than the power limit value.

[0124] In this embodiment, by configuring the first controller 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 parameters and the second discharge capacity parameters, the discharge capacity of the battery pack is determined according to the state parameters of the battery pack. This ensures that the power of the battery pack is fully utilized to maximize its capacity, while preventing overuse of the battery pack's power, thereby improving the battery pack's lifespan and safety performance.

[0125] 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 a first discharge capability parameter based on the cutoff condition and the instantaneous DC resistance of the battery pack 1; and / or determine a second discharge capability parameter based on the cutoff condition and the continuous DC resistance.

[0126] 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 before discharge acquired by the detection component 11, thereby calculating the state of charge of the battery pack 1 using the ampere-hour integration method.

[0127] The instantaneous DC resistance of battery pack 1 can be understood as the DC resistance of battery pack 1 when it is instantaneously discharged from its current state until the state of battery pack 1 meets the cutoff condition. The continuous DC resistance of battery pack 1 can be understood as the DC resistance of battery pack 1 when it is continuously discharged from its current state until the state of battery pack 1 meets the cutoff condition.

[0128] 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 looking up a table based on the temperature information and state of charge.

[0129] In some embodiments, the first discharge capability and the second discharge capability include a current limit value. Determining the first discharge capability parameter based on the cutoff condition and the instantaneous DC resistance of the battery pack 1 includes: determining the instantaneous voltage of the battery pack 1 before discharge based on current information, and determining the instantaneous discharge current limit value of the battery pack 1 based on the instantaneous voltage before discharge, the cutoff condition, and the instantaneous DC resistance of the battery pack.

[0130] The instantaneous voltage of battery pack 1 before discharge can be understood as the voltage of the battery pack at the instant before discharge, for example, the voltage within 1 second before discharge.

[0131] In some embodiments, the first discharge capability and the second discharge capability include a current limit value. Determining the second discharge capability parameter based on the cutoff condition and the continuous DC resistance includes: determining the pre-discharge continuous voltage of the battery pack 1 based on current information, and determining the continuous discharge current limit value of the battery pack 1 based on the pre-discharge continuous voltage, the cutoff condition, and the continuous DC resistance.

[0132] The continuous voltage of battery pack 1 before discharge can be understood as the voltage that battery pack 1 maintains before discharge, for example, the average voltage of battery pack 1 in the 10 seconds before discharge.

[0133] In some embodiments, the cutoff condition includes a cutoff voltage. The cutoff voltage is determined based on the lowest temperature of the battery pack 1.

[0134] The cutoff voltage can be understood as the lowest allowable voltage of battery pack 1, that is, the lowest voltage that battery pack 1 can output normally. The lowest temperature of battery pack 1 can be understood as the lowest temperature measured at each measuring point in battery pack 1. It should be noted that the value of the cutoff voltage can be set differently depending on the temperature of battery pack 1. The curve of cutoff voltage versus temperature of battery pack 1 can contain one or more curve segments.

[0135] In one exemplary embodiment, such as Figure 9As shown, when the temperature of battery pack 1 is above 0℃, the cutoff voltage Vmin of battery pack 1 can be set to 2.5V. When the temperature of battery pack 1 is below -20℃, the cutoff voltage Vmin of battery pack 1 can be set to 2V. When the temperature of battery pack 1 is above -20℃ and below 0℃, the cutoff voltage Vmin of battery pack 1 smoothly transitions from 2V to 2.5V as the temperature rises. It should be noted that... Figure 9 This example only illustrates that when the temperature of battery pack 1 is above -20°C and below 0°C, the cutoff voltage of battery pack 1 transitions linearly and smoothly from 2V to 2.5V as the temperature rises. In other embodiments, the cutoff voltage of battery pack 1 may also transition non-linearly and smoothly from 2V to 2.5V as the temperature rises. This embodiment does not specifically limit the type of smooth transition of the cutoff voltage of battery pack 1.

[0136] In some embodiments, if the instantaneous voltage or the sustained voltage before discharge is lower than the cutoff voltage, the battery pack is controlled to stop discharging, that is, the power tool 2 is controlled to stop, so as to protect the power tool 2 and extend the service life of the power tool 2.

[0137] In some embodiments, controlling the power tool 2 to stop includes controlling the power tool 2 to stop after a preset time based on current information, which helps to improve the user experience of the power tool 2.

[0138] The preset time can be set based on the 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 but greater than I2, the preset time can be set to t2. Where I1 > I2, t1 < t2 < t3.

[0139] In some embodiments, if the instantaneous voltage or sustained voltage before discharge is not lower than the cutoff voltage, current limiting protection is applied to the power tool system based on temperature parameters. It is understood that current limiting of the power tool system can be understood as current limiting protection of the battery pack or the power tool itself.

[0140] The current limiting protection of the power tool system based on temperature parameters can be understood as determining the cutoff voltage of battery pack 1 based on temperature parameters, thereby determining the discharge capacity parameters of battery pack 1, and then controlling the working state of power tool 2 based on the discharge capacity parameters of battery pack 1.

[0141] 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. 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.

[0142] 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].

[0143] In one exemplary embodiment, such as Figure 10 As shown, when the temperature of the battery pack is below -1 or above T4, the current value of the battery pack is limited to 0 mA, i.e., battery pack 1 is prohibited from discharging. When the temperature of battery pack 1 is between [T2, T3], i.e., the temperature of battery pack 1 is within the preset temperature range, the current value of battery pack 1 is controlled according to the determined discharge capacity parameter of battery pack 1. When the temperature of battery pack 1 is between [T1, T2] or [T3, T4], the current value of battery pack 1 is limited to a smooth transition between 0 and the determined current limit value. In an exemplary embodiment, a smooth transition is used between -30°C and -20°C and between 70°C and 80°C, such as by multiplying by a scaling factor that varies with temperature.

[0144] Figure 11 A flowchart illustrating a method for determining the discharge capacity parameters of a battery pack, as provided in an embodiment of this application. (Reference) Figure 11 As shown in the figure, this embodiment also provides a method for determining the discharge capacity parameters of a battery pack, as detailed below: S510, Obtain the status parameters of the battery pack.

[0145] The state parameters of the battery pack include at least one of the following: current information, voltage information, and temperature information.

[0146] S520. Calculate the state of charge of the battery pack based on the current and voltage information.

[0147] S530. Determine the instantaneous DC resistance and / or continuous DC resistance of the battery pack based on the state of charge and temperature information of the battery pack.

[0148] S540. Based on the current information, determine the instantaneous voltage and continuous voltage of the battery pack before discharge.

[0149] S550. Determine whether the instantaneous voltage or continuous voltage before discharge is lower than the cutoff voltage; if yes, proceed to S560; if no, proceed to S570.

[0150] S560: Based on the current information, control the battery pack to stop discharging after a preset time.

[0151] 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.

[0152] 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 the battery pack is instantaneously discharged until the battery pack's state meets the cutoff condition; the second discharge capability parameter includes the discharge capability of the battery pack when the battery pack is continuously discharged until the battery pack's state meets the cutoff condition. The first and second discharge capability parameters include current limiting values ​​or power limiting values.

[0153] S580 provides current-limiting protection for the battery pack based on temperature and discharge capacity parameters.

[0154] Figure 12 A flowchart illustrating another method for determining the discharge capacity parameters of a battery pack, provided as an embodiment of this application. (See reference...) Figure 12 As shown, this embodiment also provides another method for determining the discharge capacity parameters of a battery pack, which can be used to determine the values ​​of a first discharge capacity parameter and / or a second discharge capacity parameter, that is, the values ​​of instantaneous and / or continuous discharge capacity parameters. For example, it is a current limit value that meets the target continuous discharge time (the set target continuous discharge time is short, less than or equal to a first time threshold, such as 1s or 3s, which is the first discharge capacity parameter; the set target continuous discharge time is long, greater than the first time threshold, such as 10s or 30s, which is the second discharge capacity parameter), as detailed below: S610, Obtain the status parameters of the battery pack.

[0155] The battery pack's status parameters include at least one of the following: current, voltage, and temperature. These parameters can be obtained from the detection components. As described earlier, the detection components can be partially or entirely integrated into the battery pack or power tool; further details will not be elaborated here.

[0156] S620. Based on voltage constraints, determine the first reference value for the discharge capability parameter.

[0157] The first reference value, following Ohm's law, is determined based on the open-circuit voltage and resistance of the battery pack. Specifically, the current depth of discharge of the battery pack is first calculated based on the current and voltage. Based on the current depth of discharge, the corresponding current open-circuit voltage and instantaneous DC resistance are obtained, for example, by looking up a table. The instantaneous maximum discharge current can be calculated using the current open-circuit voltage and instantaneous DC resistance. Similarly, to predict the depth of discharge after the target continuous discharge time under the current operating conditions, the open-circuit voltage and continuous DC resistance after the target continuous discharge time can be obtained, for example, by looking up a table. The continuous maximum discharge current can be calculated using the open-circuit voltage and continuous DC resistance after the target continuous discharge time. As mentioned above, the relationship table between open-circuit voltage and depth of discharge 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, thereby obtaining a more accurate instantaneous DC resistance and continuous DC resistance.

[0158] S630. Based on the depth of discharge constraint, determine the second reference value of the discharge capability parameter.

[0159] The second reference value follows the battery pack capacity definition and is determined based on the battery pack's remaining capacity and the target discharge duration. Specifically, the state of charge (SOC) 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 SOC 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 the sustained maximum discharge current of the battery pack can be calculated. In one embodiment, the method described in this application can be used to learn and update the maximum chemical capacity of the battery pack when conditions permit.

[0160] S640. Based on the first and second reference values ​​mentioned above, determine the third reference value for the discharge capability parameter.

[0161] A 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 another embodiment, the third reference value is the average of the first and second reference values; in yet another embodiment, the third reference value is the smaller of the first and second reference values ​​plus an adjustment amount; and in still another embodiment, the third reference value is the average of the first and second reference values ​​minus an adjustment amount. There are many specific calculation methods available, and appropriate statistical methods can be selected through experimental sampling of specific power tools; these will not be elaborated upon here.

[0162] S650: Based on temperature, the third reference value is narrowed down to determine the discharge capability parameters.

[0163] refer to Figure 10The principle is that when the battery pack temperature is between [T1, T2] or [T3, T4], the discharge capacity parameter of the battery pack is limited to smoothly transition between 0 and a third reference value, for example, by proportional limiting. It can be understood that the temperature of the battery pack can primarily refer to the temperature of its cells. The temperature of a cell can refer to its surface temperature or its internal temperature. The surface temperature of a cell can be measured using temperature sensing elements (e.g., NTC temperature sensors), while the internal temperature of a cell can be calculated using a recursive algorithm based on the thermal conductivity effect formula. The temperature of the battery pack can be based on the temperature of the hottest cell, or other statistical methods such as the average temperature of the cells.

[0164] After the above steps, the discharge capacity parameters of the current battery pack can be determined. For example, the discharge capacity parameters include the instantaneous maximum discharge current and / or the continuous maximum discharge current. The power tool can control the discharge of the battery pack based on these discharge capacity parameters. It is understood that the above steps are illustrative combinations, based on the learned aging battery capacity and internal resistance, while also considering the battery's depth of discharge constraints, cutoff voltage constraints, sampling temperature constraints, and estimated internal battery temperature constraints to estimate the instantaneous and continuous maximum discharge capacity. In some embodiments, those skilled in the art can also omit the above steps, for example, removing S650, i.e., not considering the influence of the battery pack temperature on the current battery pack's discharge capacity, and calculating the battery pack's discharge capacity only based on the battery pack's current and voltage; or, for example, only calculating a first reference value based on the voltage constraint or only calculating a second reference value based on the depth of discharge constraint, instead of comprehensively selecting reference values ​​calculated from both constraints.

[0165] In one embodiment, the discharge capacity parameters of the battery pack can also be compensated for with precision based on the concept of closed-loop control. See also Figure 13 This application further provides a method for determining the discharge capacity parameters of a battery pack, including: S710: Obtain the status parameters of the battery pack through the detection component.

[0166] The battery pack's status parameters include at least one of the following: current, voltage, and temperature. These parameters can be obtained from the detection components. As described earlier, the detection components can be partially or entirely integrated into the battery pack or power tool; further details will not be elaborated here.

[0167] S720. Determine the discharge capability parameters based on the state parameters.

[0168] In this step, the discharge capacity parameters of the battery pack can be determined by referring to the methods in S610-S650 above or other methods. The discharge capacity parameters include at least one of a first discharge capacity parameter and a second discharge capacity parameter; the first discharge capacity parameter is the discharge capacity of the battery pack when it is instantaneously discharged to the cutoff voltage; the second discharge capacity parameter is the discharge capacity of the battery pack when it is continuously discharged to the cutoff voltage. For example, the discharge capacity parameters include the instantaneous maximum discharge current and / or the continuous maximum discharge current.

[0169] S730 limits the discharge of the battery pack according to the discharge capacity parameters, and then obtains the voltage of the battery pack again.

[0170] In this step, the power tool controls the battery pack to discharge using the discharge capacity parameters determined in S720 as limit values, and then acquires the battery pack voltage again. In practice, conventional parameters such as battery pack voltage, current, and temperature are usually continuously monitored and acquired by the detection component. The voltage acquired here may not be the result of a single detection, but rather the result of statistical analysis of detection results over a period of time. The emphasis is on the current terminal voltage of the battery pack after a certain period of control based on the discharge capacity parameters determined in step S720.

[0171] S740: Update the discharge capacity parameters based on the difference between the newly acquired voltage and the battery pack's cutoff voltage.

[0172] Specifically, the discharge capacity parameters are adjusted by comparing the difference between the current terminal voltage and the cutoff voltage, taking into account 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 too conservative. In other words, discharge capacity parameters, such as the instantaneous maximum discharge current and / or the continuous maximum discharge current, can be increased. The specific 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 too optimistic. In other words, discharge capacity parameters, such as the instantaneous maximum discharge current and / or the continuous maximum discharge current, need to be decreased. The specific 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.

[0173] In actual use of power tools, it's not always necessary to discharge at the battery pack's maximum capacity. In one embodiment, timing can be used for discharge conditions where the discharge capacity parameters are not met, and the weight of the compensation value can be determined based on the timing. For example, when the proportion of discharge conditions where the discharge capacity parameters are not met 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 update the discharge capacity parameters in real time. The method for determining the discharge capacity parameters can be executed by the first controller 12 of the battery pack 1 or the second controller 21 of the power tool 2.

[0174] This application also proposes a new concept of state of charge (SOC). The conventional SOC is the ratio of a battery's remaining capacity after a period of use or long-term storage to its capacity at full charge, usually expressed as a percentage. Its value ranges from 0 to 1, where SOC=0 indicates the battery is fully discharged, and SOC=1 indicates the battery is fully charged. The conventional SOC and depth of discharge sum to 1. That is, when the depth of discharge is 60%, the SOC is 40%; when the depth of discharge is 40%, the SOC is 60%. The capacity at full charge refers to the battery's maximum chemical capacity, which does not include the capacity lost during aging. Therefore, even if the battery has aged, for example, if its maximum chemical capacity is only 80% of its initial chemical capacity, the SOC can still reach 1 when fully charged. However, not all operating conditions allow the battery to fully discharge its maximum chemical capacity. In other words, users may find that even when using some power tools or other electrical equipment, they cannot continue to discharge even if the SOC is not 0. In particular, when using some high-current power tools, such as chainsaws and snowplows, it is impossible to fully discharge the battery's conventional State of Charge (SOC) to 0. Therefore, the conventionally defined SOC can sometimes cause confusion or trouble for users, making it difficult for them to reasonably assess the power requirements of the power tools and other electrical equipment they need to use.

[0175] To address this issue, this application proposes the concept of Relative State of Charge (RSOC). RSOC is defined as the ratio of the remaining dischargeable capacity of the battery under the current operating condition to the maximum dischargeable capacity (maximum discharge capacity) under the current operating condition; where the remaining dischargeable capacity under the current operating condition is the difference between the maximum dischargeable capacity (maximum discharge capacity) and the discharged capacity (cumulative discharge capacity). Alternatively, RSOC can also be defined as the ratio of the remaining depth of discharge under the current operating condition to the depth of discharge at the end of the current operating condition; where the remaining depth of discharge under the current operating condition is the difference between the depth of discharge at the end of the current operating condition and the current depth of discharge.

[0176] 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 based on the battery pack's state of charge, while discharging equipment primarily discharges based on operational needs. By estimating the battery pack's RSOC during discharge, devices using the battery pack's power, such as power tools, can optimize the discharge process by combining the current operating conditions and RSOC. In one embodiment, the battery pack's RSOC can also be provided to the user via a display device on the battery pack or the device, or via a mobile terminal such as a smartphone, allowing the user to reasonably assess their power needs and carry a sufficient number of battery packs.

[0177] Based on the same concept, this application also proposes a method for estimating the relative state of charge (SOC) 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. A first controller 12 is disposed on the first circuit board 16. The estimation method includes: acquiring 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; determining the final depth of discharge of the battery pack 1 under the current operating condition based on the voltage and current, and the current depth of discharge; and calculating the relative SOC of the battery pack 1 under the current operating condition based on the current depth of discharge and the final depth of discharge. In one embodiment, the relative SOC is the ratio of the difference between the final depth of discharge and the current depth of discharge to the final depth of discharge. The specific calculation process for the current depth of discharge and the final depth of discharge, as well as the calculation process for intermediate variables, can be referred to in other paragraphs of this application. Here, it is only briefly described as follows: In one embodiment, determining the current depth of discharge of battery pack 1 based on its voltage and current includes: calculating the initial depth of discharge based on the voltage of battery pack 1 when it is at rest; and calculating the current depth of discharge based on the initial depth of discharge, the maximum chemical capacity of battery pack 1, and the current. In one embodiment, the maximum chemical capacity of battery pack 1 is determined based on the initial chemical capacity and overall health status of battery pack 1. In one embodiment, the point at which the voltage of battery pack 1 reaches the discharge cutoff voltage is defined as the discharge endpoint, and the final depth of discharge is the depth of discharge corresponding to the voltage at the discharge endpoint. In one embodiment, determining the final depth of discharge of battery pack 1 under the current operating conditions based on its voltage and current, and the current depth of discharge includes: adaptively learning the impedance curve under the current operating conditions based on the voltage and current of battery pack 1, and the current depth of discharge; determining the voltage change curve of battery pack 1 under the current operating conditions based on the impedance curve and the current depth of discharge; and determining the final depth of discharge based on the voltage change curve and the discharge cutoff voltage.

[0178] Based on the same concept, this application also proposes another method for estimating the relative state of charge (SPC) 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. A first controller 12 is disposed on the first circuit board 16. The estimation method includes: acquiring the voltage and current of the battery pack 1 through a detection component 11; acquiring the cumulative discharge capacity already discharged by the battery pack 1 based on the voltage and current of the battery pack 1; acquiring 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 SPC 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 SPC 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 for the cumulative discharge capacity and maximum discharge capacity, as well as the calculation process for the intermediate variables, can be found in other paragraphs of this application. Here, it is only briefly described as follows: In one embodiment, the cumulative discharge capacity is the product of the maximum chemical capacity of battery pack 1 and the current depth of discharge of battery pack 1. In one embodiment, the maximum discharge capacity is the product of the maximum chemical capacity of battery pack 1 and the final depth of discharge of battery pack 1 under the current operating conditions.

[0179] Based on the same concept, this application also proposes an electrical equipment system capable of simultaneously providing the conventional state of charge and relative state of charge of a battery pack. This electrical equipment system includes a battery pack 1 and a host unit 2. The host unit 2 can be a power tool 2, a lamp, an energy station, etc. 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. A first controller 12 is disposed on the first circuit board 16. The host unit 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 equipment system also includes a detection component 11 for at least detecting the voltage and current of the battery pack 1. The detection component 11 is disposed within the housing 14 of the battery pack and / or within the housing 24 of the host unit. The first controller 12 or the second controller 21 is communicatively connected to the detection component 11 and configured to: acquire the voltage and current of the battery pack 1 through the detection component 11; calculate the current depth of discharge of the battery pack 1 based on the voltage and current of the battery pack; determine the final depth of discharge of the battery pack 1 under the current operating conditions based on the voltage and current of the battery pack 1 and the current depth of discharge; and determine the state of charge of the battery pack and the relative state of charge of the battery pack under the current operating conditions based on the current depth of discharge and the final depth of discharge.

[0180] In a specific embodiment, see Figures 8A to 8C The detection components 11 can be entirely located within the battery pack 1, and the first controller 12 calculates at least one of the state of charge (SOC) of the battery pack 1 and its relative SOC under the current operating condition. The detection components 11 can be distributed within the battery pack 1 and the host unit 2, and transmit the detection data uniformly to the first controller 12 or the second controller 21, which calculates at least one of the SOC of the battery pack 1 and its relative SOC under the current operating condition. As an extended embodiment, the host unit 2 can be powered not by the battery pack 1, but by a cell module 25 built into the host unit 2. The first controller 12' and the detection components 11 are located within the casing 24 of the host unit 2, and the first controller 12' or the second controller 21 calculates at least one of the SOC of the battery pack 1 and its relative SOC under the current operating condition. In one embodiment, the detection components 11 include a voltage sensor, a current sensor, and a temperature sensor. Optionally, the voltage sensor and temperature sensor are located in the battery pack 1, and the current sensor is located in the host unit 2.

[0181] Furthermore, the aforementioned electrical equipment system may also include a display device for displaying 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 to the user. The display device may be located on the battery pack 1, the host 2, or a mobile terminal such as a mobile phone.

[0182] This application also provides a method for calculating the maximum chemical capacity of a battery pack, which can be used in the aforementioned maximum chemical capacity update module 431. Conventional methods obtain the maximum charge / discharge capacity, i.e., the maximum chemical capacity, of the battery within a complete charge and / or discharge cycle by performing a full charge and / or full discharge. Conventional methods typically require stable current throughout this complete charge and / or discharge cycle, and the experimental conditions are quite stringent, which may not be frequently met in daily user operations.

[0183] The maximum chemical capacity of a battery pack is equal to the product of its state of health (SOH) and initial chemical capacity. Since the initial chemical capacity of the battery pack is fixed, calculating the maximum chemical capacity is essentially calculating the battery pack's SOH. This application proposes that the overall SOH of the battery can be obtained from a preset mapping model based on the battery's interval SOH. Therefore, the problem of determining the overall SOH of the battery can be simplified to determining the interval SOH. The interval SOH can be obtained by comparing the actual charging capacity within a preset voltage range with a health assessment benchmark value. In one embodiment, the health assessment benchmark value is the theoretical charging capacity of a brand-new battery pack within the preset voltage range. In another embodiment, the interval SOH is equal to the ratio of the actual charging capacity to the theoretical charging capacity.

[0184] Based on the above concept, this 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 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. A first controller 12 is disposed on the first circuit board 16. See also Figure 20 The evaluation methods include: S810: Estimate the health status of the battery pack within a preset voltage range during the battery pack charging process.

[0185] When the battery pack charging process meets the following conditions, the health status within a preset voltage range can be estimated during this charging process: 1. After a preset charging period begins, the battery pack voltage is lower than the minimum value of the preset voltage range. The preset charging period can be a sufficiently long period to ensure the battery pack enters a stable charging state, such as 100s, 200s, or 300s; alternatively, it can be combined with the charging current, timing from the point where the rated charging current is reached for 50s, 100s, or 200s, etc. In short, it should be a period that ensures the battery pack enters a stable charging state. If the battery pack voltage has exceeded the minimum value of the preset voltage range when entering a stable charging state, the actual charging capacity of the battery pack within the entire preset voltage range cannot be calculated during this charging process, and therefore, the range health status cannot be calculated during this charging process.

[0186] 2. After the preset charging period begins, the battery pack temperature remains within the preset temperature range. This preset temperature range refers to a suitable ambient temperature range; temperatures that are too high or too low are undesirable. If the battery pack temperature exceeds the preset temperature range after the preset charging period begins (i.e., the battery pack temperature is too low or too high), the battery pack's health status cannot be calculated during this charging process.

[0187] 3. A health assessment benchmark value matching the charging current exists. The battery pack can be coupled 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 battery pack's health status, but rather to the different charging conditions. Therefore, when charging the battery pack with different charging devices, different health assessment benchmark values ​​need to be selected. In one embodiment, multiple health assessment benchmark values ​​are pre-stored within the battery pack. Since the charging devices cannot be exhaustively listed, and the charging current is the main difference between different charging devices, the charging current can be used as the search condition to obtain a health assessment benchmark value matching the charging current during the current charging process. In one embodiment, the charging current refers to the average charging current within a 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 all the pre-stored charging currents. Therefore, no health assessment benchmark value matching the charging current during the current charging process can be found, and the interval health status cannot be calculated during this charging process.

[0188] S820. Determine the overall health status of the battery pack based on the interval health status and the preset mapping model.

[0189] During battery pack manufacturing, a mapping model from interval health status to overall health status can be established through sampling experiments, function fitting, etc., and this mapping model can be pre-stored in the battery pack or charger. This 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 lookup table method can be used to obtain the overall health status from the interval health status. In another embodiment, the preset mapping model can also be combined with parameters such as the battery pack's resistance and voltage 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, the estimated value of the current interval health status is considered abnormal and is not adopted.

[0190] When a battery pack is connected to a new charging device and no health assessment benchmark value matching the charging current during the current charging process can be found, it can self-learn and store the health assessment benchmark value corresponding to the charging current. This benchmark value can then be used to estimate the battery pack's interval health status when the charging device is used again. Specifically, the calculation method for the health assessment benchmark value includes: calculating the actual charging capacity of the battery pack within a preset voltage range during the charging process; and calculating the health assessment benchmark value of the battery pack within the preset voltage range based on the actual charging capacity and the stored interval health status of the battery pack. The actual charging capacity can be calculated using the ampere-hour integration method. When using a new charging device, assuming that the battery pack's health status does not change abruptly after this charging, the previously calculated interval health status of the battery pack is used as a reference to deduce the health assessment benchmark value corresponding to the current charging device, or in other words, the current charging current. The calculated health assessment benchmark value can be stored in the battery pack or the charging device.

[0191] The aforementioned method for assessing the health status of battery pack 1 can be performed by battery pack 1 or charger 2', specifically by the first controller 12 of battery pack 1 or the second controller 21' of charger 2'. The detection component 11 can be installed in at least one of battery pack 1 and charger 2'. The detection component 11 can include a voltage sensor, a current sensor, and a temperature sensor to detect the voltage, charging current, and temperature of battery pack 1. Pre-stored information such as health assessment benchmark values, and detected data such as voltage and charging current, can be transmitted from battery pack 1 to charger 2' or vice versa, to facilitate the execution of the aforementioned assessment method. Furthermore, battery pack 1 or charger 2' can include a display device to show the health status (SOH) of battery pack 1 to the user. The display device can be installed on battery pack 1, charger 2', or a mobile terminal such as a mobile phone, allowing the user to understand the aging status of battery pack 1, thereby better maintaining battery pack 1 or replacing it in a timely manner.

[0192] This embodiment also provides a method for reducing lithium plating in battery packs. When lithium-ion battery packs for power tools are charged at low temperatures, high currents, or under high charge conditions, lithium metal easily deposits on the surface of the negative electrode material. In severe cases, dendritic lithium dendrites may form. The application of fast charging technology exacerbates this phenomenon, seriously affecting the battery pack's lifespan and safety. Therefore, there is an urgent need for a technology that can promptly detect the onset of lithium plating in the battery pack and adjust the charging power accordingly, in order to reduce or eliminate lithium plating while maintaining fast charging speeds, thereby improving the battery pack's lifespan and safety.

[0193] This embodiment provides a method for reducing lithium plating in battery packs as follows: During battery pack charging, at each first set time interval, the charging current is reduced to a set value and maintained for a second set time interval. The changes in current ΔI and voltage ΔV of the battery pack during the reduction of the charging current are checked, 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 the 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.

[0194] The first set time period can be set according to the charging state of the battery pack, such as at least one of the charging temperature, charging current, and state of charge of the battery pack. In some embodiments, the set time period can be 60 seconds.

[0195] Both 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.

[0196] 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 a set value according to a second formula. The second formula is: Z = ΔV / ΔI, where Z is the charge transfer impedance of the battery pack.

[0197] The first setting rule can be determined based on actual conditions. In some embodiments, the first setting rule is a fixed value, that is, the maximum allowable charging current value of 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 allowable charging current value of the battery pack is reduced by a variable step size. For example, 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 by a small amount, the maximum allowable charging current value of the battery pack is reduced by a first step size; when the calculated charge transfer impedance is more than the charge transfer impedance corresponding to the corresponding state of charge in the stored charge transfer impedance table by a large amount, the maximum allowable charging current value of the battery pack is reduced by a second step size, wherein the first step size is smaller than the second step size.

[0198] Another method for reducing lithium plating in battery packs provided in this embodiment is as follows: During battery pack charging, at each first set time interval, the charging current is reduced to a set value and maintained for a second set time interval. The change in current ΔI and voltage ΔV of the battery pack during the reduction of the charging current are checked, 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 consecutive times or more is less than the charge transfer impedance of the battery pack calculated at the previous moment, the maximum allowable charging current value of the battery pack is reduced according to the second set rule.

[0199] 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.

[0200] Another method for reducing lithium plating in a battery pack provided in this embodiment is as follows: During the charging process of the battery pack, the lithium plating situation of the battery pack is detected in real time. When lithium plating is detected, the charging current of the battery pack is reduced according to a third set rule until lithium plating is no longer detected.

[0201] The methods for detecting lithium plating in battery packs may include, but are not limited to, pulse charging detection charge transfer impedance method, low current method, impedance-capacity method, and voltage relaxation method.

[0202] The third setting rule can be set according to the actual situation. 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.

[0203] The foregoing has shown and described 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 way, and all technical solutions obtained by equivalent substitution or equivalent transformation fall within the protection scope of this application.

Claims

1. A method for determining the discharge capacity parameter of a battery pack (1), the battery pack (1) comprising: Shell (14); Multiple battery cells (15) are housed within the housing (14); A power tool interface (13) is disposed in the housing (14); and a first circuit board (16) is housed in the housing (14) and electrically connected to the power tool interface (13), wherein a first controller (12) is disposed on the first circuit board (16); the method for determining the discharge capacity parameters of the battery pack (1) includes: The voltage and current of the battery pack (1) are obtained by the detection component (11); The discharge capacity parameters are determined based on the voltage and current of the battery pack (1); Based on the discharge capacity parameters, the discharge of the battery pack (1) is limited, and then the voltage of the battery pack (1) is obtained again; and The discharge capability parameter is updated based on the difference between the voltage obtained again and the cutoff voltage of the battery pack (1).

2. The method for determining the discharge capacity parameters of the battery pack (1) according to claim 1, characterized in that, 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 is the discharge capability of the battery pack (1) when it is controlled to discharge instantaneously to the cutoff voltage; the second discharge capability parameter is the discharge capability of the battery pack (1) when it is controlled to discharge continuously to the cutoff voltage.

3. The method for determining the discharge capacity parameters of the battery pack (1) according to claim 2, characterized in that, The first discharge capability parameter is defined as the target continuous discharge time being less than or equal to the first time threshold; the second discharge capability parameter is defined as the target continuous discharge time being greater than the first time threshold.

4. The method for determining the discharge capacity parameters of the battery pack (1) according to claim 1, characterized in that, The discharge capability parameter is a current limit value or a power limit value.

5. The method for determining the discharge capacity parameters of the battery pack (1) according to claim 1, characterized in that, The discharge capacity parameters are determined based on the voltage and current of the battery pack (1), including: A first reference value for the discharge capability parameter is determined based on voltage constraints; A second reference value for the discharge capability parameter is determined based on the depth of discharge constraint; Based on the first reference value and the second reference value, a third reference value for the discharge capability parameter is determined; The discharge capability parameter is determined by narrowing the third reference value based on temperature.

6. The method for determining the discharge capacity parameters of the battery pack (1) according to claim 5, characterized in that, The first reference value is determined based on the open-circuit voltage and resistance of the battery pack (1).

7. The method for determining the discharge capacity parameters of the battery pack (1) according to claim 5, characterized in that, The second reference value is determined based on the remaining capacity of the battery pack (1).

8. The method for determining the discharge capacity parameters of the battery pack (1) according to claim 5, characterized in that, The third reference value is the smaller of the first reference value and the second reference value.

9. The method for determining the discharge capacity parameters of the battery pack (1) according to claim 1, characterized in that, Updating the discharge capability parameter includes: determining a compensation value for the discharge capability parameter based on the difference and the resistance of the battery pack (1).

10. The method for determining the discharge capacity parameters of the battery pack (1) according to claim 9, characterized in that, Updating the discharge capability parameter also includes timing the discharge conditions that do not reach the discharge capability parameter, and determining the weight of the compensation value based on the timing.

11. A battery pack (1), characterized in that, include: Shell (14); Multiple battery cells (15) are housed within the housing (14); A detection component (11) is used to detect the status parameters of the battery pack (1); A first circuit board (16) is housed within the housing (14), and a first controller (12) is provided on the first circuit board (16). The first controller (12) is communicatively connected to the detection component (11), and the first control configuration (11) is as follows: Obtain the status parameters of the battery pack (1); Based on the state parameters, the discharge capability parameters of the battery pack (1) are determined; wherein, 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 includes the discharge capability of the battery pack (1) when the state of the battery pack (1) is instantaneously discharged to the point where the state of the battery pack (1) meets the cutoff condition; the second discharge capability parameter includes the discharge capability of the battery pack (1) when the state of the battery pack (1) is continuously discharged to the point where the state of the battery pack (1) meets the cutoff condition; 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 capability parameters to the power tool (2).

12. The battery pack according to claim 11, characterized in that, The discharge capability parameters include current limit values ​​or power limit values.

13. The battery pack according to claim 12, characterized in that, The status parameters include the current, voltage, and temperature of the battery pack (1); the first controller (12) is specifically configured as follows: Calculate the state of charge of the battery pack based on the current and the voltage; Based on the state of charge and the temperature, determine the instantaneous DC resistance and / or continuous DC resistance of the battery pack; The first discharge capability parameter is determined based on the cutoff condition and the instantaneous DC resistance of the battery pack. And / or, the second discharge capability parameter is determined based on the cutoff condition and the continuous DC resistance.

14. The battery pack according to claim 13, characterized in that, The first controller (12) is also configured to: Based on the current, determine the instantaneous voltage and sustained voltage of the battery pack before discharge; The first discharge capability parameter is determined based on the instantaneous voltage before discharge, the cutoff condition, and the instantaneous DC resistance of the battery pack. And / or, the second discharge capability parameter is determined based on the pre-discharge continuous voltage, the cutoff condition, and the continuous DC resistance; The first discharge capability parameter and the second discharge capability parameter include the current limit value.

15. The battery pack according to claim 12, characterized in that, The status parameters include the current, voltage, and temperature of the battery pack (1); the first controller (12) is specifically configured as follows: A first reference value for the discharge capability parameter is determined based on voltage constraints; A second reference value for the discharge capability parameter is determined based on the depth of discharge constraint; Based on the first reference value and the second reference value, a third reference value is determined; The discharge capability parameter is determined by narrowing the third reference value based on temperature.

16. A power tool system, comprising: Battery pack (1), comprising: Shell (14); Multiple battery cells (15) are housed within the housing (14); Power tool interface (13) is provided in the housing (14); and The first circuit board (16) is 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). Power tools (2), including: Casing (24); The battery pack interface (23), located in the housing (24), is used for electrical and communication connection with the power tool interface (13); and The second circuit board is housed in the housing (24) and electrically connected to the battery pack interface (23). The second circuit board is provided with a second controller (21). A detection component (11) is used to detect at least the voltage and current of the battery pack (1), and the detection component (11) is disposed in the housing (14) of the battery pack (1) and / or the housing (24) of the power tool (2); The first controller (12) or the second controller (21) is communicatively connected to the detection component (11) and configured as follows: Obtain the voltage and current of the battery pack (1); Based on the voltage and current of the battery pack (1), the discharge capacity parameters of the battery pack (1) are determined; wherein, the discharge capacity parameters include at least one of a first discharge capacity parameter and a second discharge capacity parameter; the first discharge capacity parameter includes the discharge capacity of the battery pack (1) when the battery pack (1) is instantaneously discharged to the point where the state of the battery pack (1) meets the cutoff condition; the second discharge capacity parameter includes the discharge capacity of the battery pack (1) when the battery pack (1) is continuously discharged to the point where the state of the battery pack (1) meets the cutoff condition; The second controller (21) is further configured to control the power tool (2) to discharge according to the discharge capability parameters.

17. The power tool system according to claim 16, characterized in that, When the first controller (12) is configured to determine the discharge capacity parameters of the battery pack (1), it further sends the discharge capacity parameters to the second controller (21) through the power tool interface (13) and the battery pack interface (23).

18. The power tool system according to claim 16, characterized in that, After the second controller (21) controls the power tool to discharge according to the discharge capability parameter, the first controller (12) or the second controller (21) is further configured to: acquire the voltage of the battery pack (1) again; and update the discharge capability parameter according to the difference between the acquired voltage and the cutoff voltage of the battery pack (1).

19. The power tool system according to claim 18, characterized in that, Updating the discharge capability parameter includes: determining a compensation value for the discharge capability parameter based on the difference and the resistance of the battery pack (1).

20. The power tool system according to claim 19, characterized in that, Updating the discharge capability parameter also includes timing the discharge conditions that do not reach the discharge capability parameter, and determining the weight of the compensation value based on the timing.

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